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    15 January 2025, Volume 20 Issue 1 Previous Issue   
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    Letter from the Editor-in-Chief
    Kwok-Fai So
    2025, 20 (1):  5.  doi: 10.4103/NRR.NRR-D-24-00447
    Abstract ( 62 )   PDF (288KB) ( 7 )   Save
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    Regulation and function of endoplasmic reticulum autophagy in neurodegenerative diseases
    Xiu-Yun Zhao, De-En Xu, Ming-Lei Wu, Ji-Chuan Liu, Zi-Ling Shi, Quan-Hong Ma
    2025, 20 (1):  6-20.  doi: 10.4103/NRR.NRR-D-23-00995
    Abstract ( 146 )   PDF (3242KB) ( 61 )   Save
    The endoplasmic reticulum, a key cellular organelle, regulates a wide variety of cellular activities. Endoplasmic reticulum autophagy, one of the quality control systems of the endoplasmic reticulum, plays a pivotal role in maintaining endoplasmic reticulum homeostasis by controlling endoplasmic reticulum turnover, remodeling, and proteostasis. In this review, we briefly describe the endoplasmic reticulum quality control system, and subsequently focus on the role of endoplasmic reticulum autophagy, emphasizing the spatial and temporal mechanisms underlying the regulation of endoplasmic reticulum autophagy according to cellular requirements. We also summarize the evidence relating to how defective or abnormal endoplasmic reticulum autophagy contributes to the pathogenesis of neurodegenerative diseases. In summary, this review highlights the mechanisms associated with the regulation of endoplasmic reticulum autophagy and how they influence the pathophysiology of degenerative nerve disorders. This review would help researchers to understand the roles and regulatory mechanisms of endoplasmic reticulum-phagy in neurodegenerative disorders.
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    Exploiting fly models to investigate rare human neurological disorders
    Tomomi Tanaka, Hyung-Lok Chung
    2025, 20 (1):  21-28.  doi: 10.4103/NRR.NRR-D-23-01847
    Abstract ( 132 )   PDF (1071KB) ( 32 )   Save
    Rare neurological diseases, while individually are rare, collectively impact millions globally, leading to diverse and often severe neurological symptoms. Often attributed to genetic mutations that disrupt protein function or structure, understanding their genetic basis is crucial for accurate diagnosis and targeted therapies. To investigate the underlying pathogenesis of these conditions, researchers often use non-mammalian model organisms, such as Drosophila (fruit flies), which is valued for their genetic manipulability, cost-efficiency, and preservation of genes and biological functions across evolutionary time. Genetic tools available in Drosophila, including CRISPR-Cas9, offer a means to manipulate gene expression, allowing for a deep exploration of the genetic underpinnings of rare neurological diseases. Drosophila boasts a versatile genetic toolkit, rapid generation turnover, and ease of large-scale experimentation, making it an invaluable resource for identifying potential drug candidates. Researchers can expose flies carrying disease-associated mutations to various compounds, rapidly pinpointing promising therapeutic agents for further investigation in mammalian models and, ultimately, clinical trials. In this comprehensive review, we explore rare neurological diseases where fly research has significantly contributed to our understanding of their genetic basis, pathophysiology, and potential therapeutic implications. We discuss rare diseases associated with both neuron-expressed and glial-expressed genes. Specific cases include mutations in CDK19 resulting in epilepsy and developmental delay, mutations in TIAM1 leading to a neurodevelopmental disorder with seizures and language delay, and mutations in IRF2BPL causing seizures, a neurodevelopmental disorder with regression, loss of speech, and abnormal movements. And we explore mutations in EMC1 related to cerebellar atrophy, visual impairment, psychomotor retardation, and gain-of-function mutations in ACOX1 causing Mitchell syndrome. Loss-of-function mutations in ACOX1 result in ACOX1 deficiency, characterized by very-long-chain fatty acid accumulation and glial degeneration. Notably, this review highlights how modeling these diseases in Drosophila has provided valuable insights into their pathophysiology, offering a platform for the rapid identification of potential therapeutic interventions. Rare neurological diseases involve a wide range of expression systems, and sometimes common phenotypes can be found among different genes that cause abnormalities in neurons or glia. Furthermore, mutations within the same gene may result in varying functional outcomes, such as complete loss of function, partial loss of function, or gain-of-function mutations. The phenotypes observed in patients can differ significantly, underscoring the complexity of these conditions. In conclusion, Drosophila represents an indispensable and cost-effective tool for investigating rare neurological diseases. By facilitating the modeling of these conditions, Drosophila contributes to a deeper understanding of their genetic basis, pathophysiology, and potential therapies. This approach accelerates the discovery of promising drug candidates, ultimately benefiting patients affected by these complex and understudied diseases.
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    Microglia lactylation in relation to central nervous system diseases
    Hui Yang, Nan Mo, Le Tong, Jianhong Dong, Ziwei Fan, Mengxian Jia, Juanqing Yue, Ying Wang
    2025, 20 (1):  29-40.  doi: 10.4103/NRR.NRR-D-23-00805
    Abstract ( 491 )   PDF (1305KB) ( 188 )   Save
    The development of neurodegenerative diseases is closely related to the disruption of central nervous system homeostasis. Microglia, as innate immune cells, play important roles in the maintenance of central nervous system homeostasis, injury response, and neurodegenerative diseases. Lactate has been considered a metabolic waste product, but recent studies are revealing ever more of the physiological functions of lactate. Lactylation is an important pathway in lactate function and is involved in glycolysis-related functions, macrophage polarization, neuromodulation, and angiogenesis and has also been implicated in the development of various diseases. This review provides an overview of the lactate metabolic and homeostatic regulatory processes involved in microglia lactylation, histone versus non-histone lactylation, and therapeutic approaches targeting lactate. Finally, we summarize the current research on microglia lactylation in central nervous system diseases. A deeper understanding of the metabolic regulatory mechanisms of microglia lactylation will provide more options for the treatment of central nervous system diseases.
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    Pyrroloquinoline quinone: a potential neuroprotective compound for neurodegenerative diseases targeting metabolism
    Alessio Canovai, Pete A. Williams
    2025, 20 (1):  41-53.  doi: 10.4103/NRR.NRR-D-23-01921
    Abstract ( 110 )   PDF (765KB) ( 45 )   Save
    Pyrroloquinoline quinone is a quinone described as a cofactor for many bacterial dehydrogenases and is reported to exert an effect on metabolism in mammalian cells/tissues. Pyrroloquinoline quinone is present in the diet being available in foodstuffs, conferring the potential of this compound to be supplemented by dietary administration. Pyrroloquinoline quinone’s nutritional role in mammalian health is supported by the extensive deficits in reproduction, growth, and immunity resulting from the dietary absence of pyrroloquinoline quinone, and as such, pyrroloquinoline quinone has been considered as a “new vitamin.” Although the classification of pyrroloquinoline quinone as a vitamin needs to be properly established, the wide range of benefits for health provided has been reported in many studies. In this respect, pyrroloquinoline quinone seems to be particularly involved in regulating cell signaling pathways that promote metabolic and mitochondrial processes in many experimental contexts, thus dictating the rationale to consider pyrroloquinoline quinone as a vital compound for mammalian life. Through the regulation of different metabolic mechanisms, pyrroloquinoline quinone may improve clinical deficits where dysfunctional metabolism and mitochondrial activity contribute to induce cell damage and death. Pyrroloquinoline quinone has been demonstrated to have neuroprotective properties in different experimental models of neurodegeneration, although the link between pyrroloquinoline quinone-promoted metabolism and improved neuronal viability in some of such contexts is still to be fully elucidated. Here, we review the general properties of pyrroloquinoline quinone and its capacity to modulate metabolic and mitochondrial mechanisms in physiological contexts. In addition, we analyze the neuroprotective properties of pyrroloquinoline quinone in different neurodegenerative conditions and consider future perspectives for pyrroloquinoline quinone’s potential in health and disease.
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    Targeting epigenetic mechanisms in amyloid-β–mediated Alzheimer’s pathophysiology: unveiling therapeutic potential
    Jennie Z. Li, Nagendran Ramalingam, Shaomin Li
    2025, 20 (1):  54-66.  doi: 10.4103/NRR.NRR-D-23-01827
    Abstract ( 71 )   PDF (726KB) ( 17 )   Save
    Alzheimer’s disease is a prominent chronic neurodegenerative condition characterized by a gradual decline in memory leading to dementia. Growing evidence suggests that Alzheimer’s disease is associated with accumulating various amyloid-β oligomers in the brain, influenced by complex genetic and environmental factors. The memory and cognitive deficits observed during the prodromal and mild cognitive impairment phases of Alzheimer’s disease are believed to primarily result from synaptic dysfunction. Throughout life, environmental factors can lead to enduring changes in gene expression and the emergence of brain disorders. These changes, known as epigenetic modifications, also play a crucial role in regulating the formation of synapses and their adaptability in response to neuronal activity. In this context, we highlight recent advances in understanding the roles played by key components of the epigenetic machinery, specifically DNA methylation, histone modification, and microRNAs, in the development of Alzheimer’s disease, synaptic function, and activity-dependent synaptic plasticity. Moreover, we explore various strategies, including enriched environments, exposure to non-invasive brain stimulation, and the use of pharmacological agents, aimed at improving synaptic function and enhancing long-term potentiation, a process integral to epigenetic mechanisms. Lastly, we deliberate on the development of effective epigenetic agents and safe therapeutic approaches for managing Alzheimer’s disease. We suggest that addressing Alzheimer’s disease may require distinct tailored epigenetic drugs targeting different disease stages or pathways rather than relying on a single drug.
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    Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke: current evidence and future perspectives
    Yubo Wang, Tingli Yuan, Tianjie Lyu, Ling Zhang, Meng Wang, Zhiying He, Yongjun Wang, Zixiao Li
    2025, 20 (1):  67-81.  doi: 10.4103/1673-5374.393104
    Abstract ( 168 )   PDF (6700KB) ( 185 )   Save
    Ischemic stroke is a leading cause of death and disability worldwide, with an increasing trend and tendency for onset at a younger age. China, in particular, bears a high burden of stroke cases. In recent years, the inflammatory response after stroke has become a research hotspot: understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment. This review summarizes several major cells involved in the inflammatory response following ischemic stroke, including microglia, neutrophils, monocytes, lymphocytes, and astrocytes. Additionally, we have also highlighted the recent progress in various treatments for ischemic stroke, particularly in the field of stem cell therapy. Overall, understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes. Stem cell therapy may potentially become an important component of ischemic stroke treatment.
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    Multisensory mechanisms of gait and balance in Parkinson’s disease: an integrative review
    Stiven Roytman, Rebecca Paalanen, Giulia Carli, Uros Marusic, Prabesh Kanel, Teus van Laar, Nico I. Bohnen
    2025, 20 (1):  82-92.  doi: 10.4103/NRR.NRR-D-23-01484
    Abstract ( 99 )   PDF (1358KB) ( 84 )   Save
    Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population. Posture and gait control does not happen automatically, as previously believed, but rather requires continuous involvement of central nervous mechanisms. To effectively exert control over the body, the brain must integrate multiple streams of sensory information, including visual, vestibular, and somatosensory signals. The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work. Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults. Insufficient emphasis, however, has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance. In the present work, we review the contributions of somatosensory, visual, and vestibular modalities, along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s disease. We also review evidence of vestibular contributions to multisensory temporal binding windows, previously shown to be highly pertinent to fall risk in older adults. Lastly, we relate multisensory vestibular mechanisms to potential neural substrates, both at the level of neurobiology (concerning positron emission tomography imaging) and at the level of electrophysiology (concerning electroencephalography). We hope that this integrative review, drawing influence across multiple subdisciplines of neuroscience, paves the way for novel research directions and therapeutic neuromodulatory approaches, to improve the lives of older adults and patients with neurodegenerative diseases.
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    Recent progress in the applications of presynaptic dopaminergic positron emission tomography imaging in parkinsonism
    Yujie Yang, Xinyi Li, Jiaying Lu, Jingjie Ge, Mingjia Chen, Ruixin Yao, Mei Tian, Jian Wang, Fengtao Liu, Chuantao Zuo
    2025, 20 (1):  93-106.  doi: 10.4103/1673-5374.391180
    Abstract ( 113 )   PDF (2996KB) ( 36 )   Save
    Nowadays, presynaptic dopaminergic positron emission tomography, which assesses deficiencies in dopamine synthesis, storage, and transport, is widely utilized for early diagnosis and differential diagnosis of parkinsonism. This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism. We conducted a thorough literature search using reputable databases such as PubMed and Web of Science. Selection criteria involved identifying peer-reviewed articles published within the last 5 years, with emphasis on their relevance to clinical applications. The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis. Moreover, when employed in conjunction with other imaging modalities and advanced analytical methods, presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker. This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion. In summary, the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials, ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.
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    High mobility group box 1 in the central nervous system: regeneration hidden beneath inflammation
    Hanki Kim, Bum Jun Kim, Seungyon Koh, Hyo Jin Cho, Xuelian Jin, Byung Gon Kim, Jun Young Choi
    2025, 20 (1):  107-115.  doi: 10.4103/NRR.NRR-D-23-01964
    Abstract ( 59 )   PDF (2200KB) ( 27 )   Save
    High-mobility group box 1 was first discovered in the calf thymus as a DNA-binding nuclear protein and has been widely studied in diverse fields, including neurology and neuroscience. High-mobility group box 1 in the extracellular space functions as a pro-inflammatory damage-associated molecular pattern, which has been proven to play an important role in a wide variety of central nervous system disorders such as ischemic stroke, Alzheimer’s disease, frontotemporal dementia, Parkinson’s disease, multiple sclerosis, epilepsy, and traumatic brain injury. Several drugs that inhibit high-mobility group box 1 as a damage-associated molecular pattern, such as glycyrrhizin, ethyl pyruvate, and neutralizing anti-high-mobility group box 1 antibodies, are commonly used to target high-mobility group box 1 activity in central nervous system disorders. Although it is commonly known for its detrimental inflammatory effect, high-mobility group box 1 has also been shown to have beneficial pro-regenerative roles in central nervous system disorders. In this narrative review, we provide a brief summary of the history of high-mobility group box 1 research and its characterization as a damage-associated molecular pattern, its downstream receptors, and intracellular signaling pathways, how high-mobility group box 1 exerts the repair-favoring roles in general and in the central nervous system, and clues on how to differentiate the pro-regenerative from the pro-inflammatory role. Research targeting high-mobility group box 1 in the central nervous system may benefit from differentiating between the two functions rather than overall suppression of high-mobility group box 1.
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    Non-coding RNAs in acute ischemic stroke: from brain to periphery
    Shuo Li, Zhaohan Xu, Shiyao Zhang, Huiling Sun, Xiaodan Qin, Lin Zhu, Teng Jiang, Junshan Zhou, Fuling Yan, Qiwen Deng
    2025, 20 (1):  116-129.  doi: 10.4103/NRR.NRR-D-23-01292
    Abstract ( 101 )   PDF (2617KB) ( 65 )   Save
    Acute ischemic stroke is a clinical emergency and a condition with high morbidity, mortality, and disability. Accurate predictive, diagnostic, and prognostic biomarkers and effective therapeutic targets for acute ischemic stroke remain undetermined. With innovations in high-throughput gene sequencing analysis, many aberrantly expressed non-coding RNAs (ncRNAs) in the brain and peripheral blood after acute ischemic stroke have been found in clinical samples and experimental models. Differentially expressed ncRNAs in the post-stroke brain were demonstrated to play vital roles in pathological processes, leading to neuroprotection or deterioration, thus ncRNAs can serve as therapeutic targets in acute ischemic stroke. Moreover, distinctly expressed ncRNAs in the peripheral blood can be used as biomarkers for acute ischemic stroke prediction, diagnosis, and prognosis. In particular, ncRNAs in peripheral immune cells were recently shown to be involved in the peripheral and brain immune response after acute ischemic stroke. In this review, we consolidate the latest progress of research into the roles of ncRNAs (microRNAs, long ncRNAs, and circular RNAs) in the pathological processes of acute ischemic stroke–induced brain damage, as well as the potential of these ncRNAs to act as biomarkers for acute ischemic stroke prediction, diagnosis, and prognosis. Findings from this review will provide novel ideas for the clinical application of ncRNAs in acute ischemic stroke.
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    Multifaceted superoxide dismutase 1 expression in amyotrophic lateral sclerosis patients: a rare occurrence?
    Ilaria Martinelli, Jessica Mandrioli, Andrea Ghezzi, Elisabetta Zucchi, Giulia Gianferrari, Cecilia Simonini, Francesco Cavallieri, Franco Valzania
    2025, 20 (1):  130-138.  doi: 10.4103/NRR.NRR-D-23-01904
    Abstract ( 54 )   PDF (1122KB) ( 106 )   Save
    Amyotrophic lateral sclerosis (ALS) is a neuromuscular condition resulting from the progressive degeneration of motor neurons in the cortex, brainstem, and spinal cord. While the typical clinical phenotype of ALS involves both upper and lower motor neurons, human and animal studies over the years have highlighted the potential spread to other motor and non-motor regions, expanding the phenotype of ALS. Although superoxide dismutase 1 (SOD1) mutations represent a minority of ALS cases, the SOD1 gene remains a milestone in ALS research as it represents the first genetic target for personalized therapies. Despite numerous single case reports or case series exhibiting extramotor symptoms in patients with ALS mutations in SOD1 (SOD1-ALS), no studies have comprehensively explored the full spectrum of extramotor neurological manifestations in this subpopulation. In this narrative review, we analyze and discuss the available literature on extrapyramidal and non-motor features during SOD1-ALS. The multifaceted expression of SOD1 could deepen our understanding of the pathogenic mechanisms, pointing towards a multidisciplinary approach for affected patients in light of new therapeutic strategies for SOD1-ALS.
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    The autophagy–lysosome pathway: a potential target in the chemical and gene therapeutic strategies for Parkinson’s disease
    Fengjuan Jiao, Lingyan Meng, Kang Du, Xuezhi Li
    2025, 20 (1):  139-158.  doi: 10.4103/NRR.NRR-D-23-01195
    Abstract ( 311 )   PDF (3951KB) ( 201 )   Save
    Parkinson’s disease is a common neurodegenerative disease with movement disorders associated with the intracytoplasmic deposition of aggregate proteins such as α-synuclein in neurons. As one of the major intracellular degradation pathways, the autophagy-lysosome pathway plays an important role in eliminating these proteins. Accumulating evidence has shown that upregulation of the autophagy-lysosome pathway may contribute to the clearance of α-synuclein aggregates and protect against degeneration of dopaminergic neurons in Parkinson’s disease. Moreover, multiple genes associated with the pathogenesis of Parkinson’s disease are intimately linked to alterations in the autophagy-lysosome pathway. Thus, this pathway appears to be a promising therapeutic target for treatment of Parkinson’s disease. In this review, we briefly introduce the machinery of autophagy. Then, we provide a description of the effects of Parkinson’s disease–related genes on the autophagy-lysosome pathway. Finally, we highlight the potential chemical and genetic therapeutic strategies targeting the autophagy–lysosome pathway and their applications in Parkinson’s disease.
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    Brain region–specific roles of brain-derived neurotrophic factor in social stress–induced depressive-like behavior
    Man Han, Deyang Zeng, Wei Tan, Xingxing Chen, Shuyuan Bai, Qiong Wu, Yushan Chen, Zhen Wei, Yufei Mei, Yan Zeng
    2025, 20 (1):  159-173.  doi: 10.4103/NRR.NRR-D-23-01419
    Abstract ( 146 )   PDF (2886KB) ( 65 )   Save
    Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response. Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific, particularly involving the corticolimbic system, including the ventral tegmental area, nucleus accumbens, prefrontal cortex, amygdala, and hippocampus. Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology. In this review, we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression. We focused on associated molecular pathways and neural circuits, with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit. We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature, severity, and duration of stress, especially in the above-mentioned brain regions of the corticolimbic system. Therefore, BDNF might be a biological indicator regulating stress-related processes in various brain regions.
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    Emerging structures and dynamic mechanisms of γ-secretase for Alzheimer’s disease
    Yinglong Miao, Michael S. Wolfe
    2025, 20 (1):  174-180.  doi: 10.4103/NRR.NRR-D-23-01781
    Abstract ( 138 )   PDF (4028KB) ( 36 )   Save
    γ-Secretase, called “the proteasome of the membrane,” is a membrane-embedded protease complex that cleaves 150+ peptide substrates with central roles in biology and medicine, including amyloid precursor protein and the Notch family of cell-surface receptors. Mutations in γ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease. γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well. However, critical gaps remain in understanding the mechanisms of processive proteolysis of substrates, the effects of familial Alzheimer’s disease mutations, and allosteric modulation of substrate cleavage by γ-secretase. In this review, we focus on recent studies of structural dynamic mechanisms of γ-secretase. Different mechanisms, including the “Fit-Stay-Trim,” “Sliding-Unwinding,” and “Tilting-Unwinding,” have been proposed for substrate proteolysis of amyloid precursor protein by γ-secretase based on all-atom molecular dynamics simulations. While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-bound γ-secretase, molecular dynamics simulations on a resolved model of Notch1-bound γ-secretase that was reconstructed using the amyloid precursor protein-bound γ-secretase as a template successfully captured γ-secretase activation for proper cleavages of both wildtype and mutant Notch, being consistent with biochemical experimental findings. The approach could be potentially applied to decipher the processing mechanisms of various substrates by γ-secretase. In addition, controversy over the effects of familial Alzheimer’s disease mutations, particularly the issue of whether they stabilize or destabilize γ-secretase-substrate complexes, is discussed. Finally, an outlook is provided for future studies of γ-secretase, including pathways of substrate binding and product release, effects of modulators on familial Alzheimer’s disease mutations of the γ-secretase-substrate complexes. Comprehensive understanding of the functional mechanisms of γ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.
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    Does mesenchymal stem cell’s secretome affect spinal sensory circuits? Implication for pain therapies
    Francesco Ferrini, Esri H. Juárez, Adalberto Merighi
    2025, 20 (1):  181-183.  doi: 10.4103/NRR.NRR-D-23-01967
    Abstract ( 68 )   PDF (538KB) ( 35 )   Save
    Mesenchymal stem cells (MSCs) are multipotent adult stem cells of mesodermal origin that can be isolated from various tissues, including bone marrow, tooth pulp, adipose tissue, and umbilical cord. MSCs have gained significant attention in regenerative medicine due to their ability to modulate the immune system and favor tissue repair. MSCs enrich the medium in which they are cultivated with a broad range of bioactive molecules, including growth factors, cytokines, chemokines, enzymes, nucleic acids, and extracellular vesicles that collectively compose the MSC secretome. An increasing number of pre-clinical studies suggest that delivering in vivo an MSC-conditioned medium (i.e., the medium collected from MSC cultures after at least 3 days of exposure) exerts neuroprotective and anti-inflammatory effects in a variety of neurological conditions, including chronic pain. Importantly, since therapies based on MSC transplantation are highly impaired by the limited cell survival in the host and by the potential occurrence of immunological adverse responses, MSC secretome represents a safer and more viable alternative to these therapies.
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    Comparing role of ATP between acute pain in neuromyelitis optica spectrum disorder and peripheral neuropathic pain
    Teruyuki Ishikura, Tatsusada Okuno
    2025, 20 (1):  184-185.  doi: 10.4103/NRR.NRR-D-23-01637
    Abstract ( 65 )   PDF (424KB) ( 16 )   Save
    In this article, we present our previous research, which highlighted adenosine triphosphate (ATP) as the cause of neuropathic pain during the acute phase of neuromyelitis optica spectrum disorder (NMOSD). In NMOSD pathology, damage-associated molecular patterns (DAMPs), including ATP, are released from damaged astrocytes, triggering the activation of innate immune cells. ATP is a central mediator of acute pain in NMOSD. We delve into the mechanisms of ATP in peripheral neuropathic pain, drawing comparisons with our findings in NMOSD. Additionally, we address the intricacies of chronic pain associated with NMOSD.
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    Unveiling the brain’s symphony: exploring the necessity and sufficiency of neural networks in behavior control
    Fernando Jose Bustos
    2025, 20 (1):  186-187.  doi: 10.4103/NRR.NRR-D-23-02084
    Abstract ( 73 )   PDF (688KB) ( 25 )   Save
    Since the pioneering work by Broca and Wernicke in the 19th century, who examined individuals with brain lesions to associate them with specific behaviors, it was evident that behaviors are complex and cannot be fully attributable to specific brain areas alone. Instead, they involve connectivity among brain areas, whether close or distant. At that time, this approach was considered the optimal way to dissect brain circuitry and function. These pioneering efforts opened the field to explore the necessity or sufficiency of brain areas in controlling behavior and hence dissecting brain function. However, the connectivity of the brain and the mechanisms through which various brain regions regulate specific behaviors, either individually or collaboratively, remain largely elusive. Utilizing animal models, researchers have endeavored to unravel the necessity or sufficiency of specific brain areas in influencing behavior; however, no clear associations have been firmly established.
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    Roles of N-cadherin in cerebral cortical development: cooperation with membrane trafficking and actin cytoskeletal regulation
    Shiho Ito, Takeshi Kawauchi
    2025, 20 (1):  188-190.  doi: 10.4103/NRR.NRR-D-23-02069
    Abstract ( 113 )   PDF (1808KB) ( 27 )   Save
    Cell adhesion plays pivotal roles in the morphogenesis of multicellular organisms. Epithelial cells form several types of cell-to-cell adhesion, including zonula occludens (tight junctions), zonula adhaerens (adherens junctions), and macula adhaerens (desmosomes). Although these adhesion complexes are basically observed only in epithelial cells, cadherins, which are the major cell adhesion molecules of adherens junctions, are expressed in both epithelial and non-epithelial tissues, including neural tissues (Kawauchi, 2012). The cadherin superfamily consists of more than 100 members, but classic cadherins, such as E-cadherin (Cdh1), N-cadherin (Cdh2), and R-cadherin (Cdh4), amount to about 20 members. Classic cadherins are single transmembrane proteins, which basically exhibit homophilic adhesion in an extracellular Ca2+-dependent manner. The cell adhesion activity is also regulated intracellularly. The intracellular domain of classic cadherins binds to β-catenin, which interacts with α-catenin (Figure 1). Because α-catenin binds to an actin-binding protein, vinculin, the catenin complex mediates the interaction between classic cadherins and the actin cytoskeleton, which stabilizes cell-to-cell adhesion (Kawauchi, 2012).
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    Vascular endothelial growth factor: a double-edged sword in the development of white matter lesions
    Narek Manukjan, Daniel Fulton, Zubair Ahmed, W. Matthijs Blankesteijn, Sébastien Foulquier
    2025, 20 (1):  191-192.  doi: 10.4103/NRR.NRR-D-23-01843
    Abstract ( 85 )   PDF (879KB) ( 40 )   Save
    As the population ages, the burden of age-related diseases becomes greater. Currently, over 55 million people suffer from dementia worldwide, with Alzheimer’s disease being the most common form. However, it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease (cSVD) may be a more detrimental cause for dementia (Cuadrado-Godia et al., 2018). It is estimated that 10%–30% of the elderly population and 35%–90% of all dementia patients exhibit signs of cSVD. The term cSVD refers to pathology affecting the small vessels of the brain, which can lead to lacunar cerebral infarcts, enlarged perivascular spaces, and cortical hemorrhages (Cuadrado-Godia et al., 2018). CSVD is often associated with cognitive decline, gait problems, and dementia (Cuadrado-Godia et al., 2018). To minimize disease progression, preventive measures, and early interventions, such as risk factor management, are crucial. However, due to its asymptomatic nature, the disease is often silent and diagnosed coincidentally at later stages. Thus, the window of opportunity for prevention and treatment is often missed.
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    Regeneration mechanisms and therapeutic strategies for neuromuscular junctions in aging and diseases
    Masashi Fujitani, Abu Md Mamun Tarif, Yoshinori Otani
    2025, 20 (1):  193-194.  doi: 10.4103/NRR.NRR-D-23-02055
    Abstract ( 149 )   PDF (1113KB) ( 75 )   Save
    The neuromuscular junction (NMJ) is an essential synaptic structure composed of motor neurons, skeletal muscles, and glial cells that orchestrate the critical process of muscle contraction (Li et al., 2018). The typical NMJ structure is classically described as having a “pretzel-like” shape in mice (Figure 1), whereas human NMJs have a smaller, fragmented structure throughout adulthood. Degenerated NMJs exhibit smaller or fragmented endplates, partial denervation, reduced numbers of synaptic vesicles, abnormal presynaptic mitochondria, and dysfunctional perisynaptic Schwann cells (Alhindi et al., 2022).
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    Compartmentalized regulation of organelle integrity in neurodegenerative diseases: lessons from the Drosophila motor neuron
    Hyun Sung
    2025, 20 (1):  195-196.  doi: 10.4103/NRR.NRR-D-23-01753
    Abstract ( 77 )   PDF (560KB) ( 34 )   Save
    Neurons are highly polarized, morphologically asymmetric, and functionally compartmentalized cells that contain long axons extending from the cell body. For this reason, their maintenance relies on spatiotemporal regulation of organelle distribution between the somatodendritic and axonal domains. Although some organelles, such as mitochondria and smooth endoplasmic reticulum, are widely distributed throughout the neuron, others are segregated to either the somatodendritic or axonal compartment. For example, Golgi outposts and acidified lysosomes are predominantly present in the somatodendritic domain and rarely distributed along the axon, whereas newly formed autophagosomes and synaptic vesicles are mainly distributed in the distal axon (Britt et al., 2016). To establish these polarized features, neurons regulate the axonal transport of organelles to maintain their distribution, integrity, and dynamics. Thus, it is not surprising that neurons in neurodegenerative diseases display early and diverse defects in organelle structure, distribution, and dynamics.
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    Alpha-synuclein in mitochondrial dysfunction: opportunities or obstacles
    Shermali Gunawardena
    2025, 20 (1):  197-198.  doi: 10.4103/NRR.NRR-D-23-01966
    Abstract ( 98 )   PDF (435KB) ( 42 )   Save
    Recent work suggests a link between α-synuclein (α-syn) and mitochondrial dysfunction; however, the mechanisms of how α-syn influences mitochondrial function are still unclear. Most notably, whether α-syn plays a direct role during mitochondrial function and/or whether diseased α-syn-mediated mitochondrial dysfunction is a potential modifiable risk factor in Parkinson’s disease (PD) is unknown.
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    Tuning beneficial calcineurin phosphatase activation to counter α-synuclein toxicity in a yeast model of Parkinson’s disease
    Srishti Chawla, Mikael Molin, Thomas Nystrom
    2025, 20 (1):  199-200.  doi: 10.4103/NRR.NRR-D-23-01917
    Abstract ( 74 )   PDF (483KB) ( 40 )   Save
    Calcineurin (CN) is a calcium- and calmodulin-dependent serine/threonine that has been studied in many model organisms including yeast, filamentous fungi, plants, and mammals. Its biological functions range from ion homeostasis and virulence in lower eukaryotes to T-cell activation in humans by human nuclear factors of activated T-cells. CN is a heterodimeric protein consisting of a catalytic subunit, calcineurin A (Cna1p), which contains an active site with a dinuclear metal center, and a regulatory Ca2+ binding subunit called calcineurin B (Cnb1p) required to activate Cna1p. The calcineurin B subunit has been highly conserved through evolution: For example, the mammalian calcineurin B shows 54% identity with calcineurin B from Saccharomyces cerevisiae. Notably, CN regulates post-translational modifications of target proteins and gene expression in parallel. The substrate selection for CN includes, but is not limited to, transcription factors, ion pumps/channels, proteins associated with mitochondria, vesicle trafficking and the polarity machinery through interactions with microtubules. The docking sites such as Short linear motifs or LxVP drive CN’s dynamic interaction and selection of its targets. The CN substrate networks in yeast and animals are distinct but share a common repertoire of target kinases, such as PKA, PKC, AKT, CAMKL, and proline-directed GSK3, CDK, and MAPK kinases. Rcn1p/RCAN1p, which regulates and activates CN in a feedback loop–dependent manner during Ca2+ stress, is the only CN target known to be conserved in yeast and mammals (Creamer, 2020). Interestingly, altered RCAN1 expression is associated with Down’s syndrome whereas its elevated expression is associated with the onset of neuronal Alzheimer’s disease (AD), Huntington’s disease, and Parkinson’s disease (PD) pathology in human patients.
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    Biomarker bust: meta-analyses reveal unreliability of neuronal extracellular vesicles for diagnosing parkinsonian disorders
    Hash Brown Taha
    2025, 20 (1):  201-202.  doi: 10.4103/NRR.NRR-D-23-02102
    Abstract ( 55 )   PDF (823KB) ( 22 )   Save
    A range of neurodegenerative disorders, collectively termed parkinsonian disorders, present with a complex array of both motor and non-motor symptoms. Included in this group are Parkinson’s disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), corticobasal syndrome (CBS), and progressive supranuclear palsy (PSP). These disorders are differentiated neuropathologically by their dominant protein pathologies involving α-synuclein (α-syn) and/or tau, the types of brain cells affected, such as neurons, oligodendroglia, and astrocytes, and the specific brain regions involved (Tolosa et al., 2021). However, because definite diagnosis can only be achieved postmortem, parkinsonian disorders commonly pose diagnostic challenges for experts in movement disorders due to parkinsonism symptom overlap (Figure 1) including bradykinesia, rigidity, and tremor. This is especially problematic in the early stages of the conditions where more distinguishable symptoms may not be yet present (Rizzo et al., 2016).
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    Fibrinogen’s potential role in connecting cerebrovascular abnormalities with glymphatic dysfunction in Alzheimer’s disease
    Vishal Singh, Arnab Choudhury, Hyung Jin Ahn
    2025, 20 (1):  203-204.  doi: 10.4103/NRR.NRR-D-23-02093
    Abstract ( 74 )   PDF (2815KB) ( 27 )   Save
    Alzheimer’s disease (AD) stands out as the primary manifestation of age-related dementia, portraying a chronic neurodegenerative disorder distinguished by the accumulation of fibrillar amyloid-β (Aβ) plaques and neurofibrillary tangles of hyperphosphorylated tau. However, from a clinical standpoint, AD presents itself as a complex condition with a spectrum of dysfunctions rather than a singular pathological mechanism. An often-overlooked aspect of the disease is the presence of extensive cerebrovascular abnormalities, given that the majority of AD patients experience altered cerebral blood flow, damaged vasculature, increased microinfarcts and microhemorrhages. Animal models of AD further support this observation, showing cerebrovascular dysfunction such as impaired cerebral blood flow and altered cerebrovascular reactivity (Tataryn et al., 2021; Gareau et al., 2023).
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    Blood biomarkers of Alzheimer’s disease: important considerations for use in clinical practice
    Sarah Fullam, Sean O’Dowd, Antoinette O’Connor
    2025, 20 (1):  205-206.  doi: 10.4103/NRR.NRR-D-23-02017
    Abstract ( 72 )   PDF (1206KB) ( 66 )   Save
    Fluid and positron emission tomography (PET) biomarkers that enable the detection of the hallmark proteins of Alzheimer’s disease (AD) (amyloid and tau) have revolutionized our approach to the diagnosis of AD. The evolution of AD diagnostic criteria to include biological characterization (Alzheimer’s Association Working Group, 2023) provides an appropriate framework to reduce levels of clinico-pathologic mismatch and improve in-vivo diagnostic accuracy. As the therapeutic landscape for neurodegenerative disease evolves, it is increasingly incumbent on clinicians to provide timely, and pathologically precise diagnoses for patients. However, the expensive and invasive nature of these tests limits their scalability.
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    Glial response in the midcingulate cortex in Huntington’s disease
    Thulani H. Palpagama, Andrea Kwakowsky
    2025, 20 (1):  207-208.  doi: 10.4103/NRR.NRR-D-23-01630
    Abstract ( 74 )   PDF (827KB) ( 13 )   Save
    Huntington’s disease (HD) is a genetic disease characterized by the progressive degeneration of the striatum and cortex. Patients can present with a variety of symptoms that can broadly be classified into motor symptoms, inclusive of choreatic movements and rigidity, mood and psychiatric symptoms, such as depression and apathy, and cognitive symptoms, such as cognitive decline. The causal mutation underlying HD results from an expansion of a CAG repeat sequence on the IT15 gene, resulting in the formation and accumulation of a mutant huntingtin protein.
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    The interaction between KIF21A and KANK1 regulates dendritic morphology and synapse plasticity in neurons
    Shi-Yan Sun, Lingyun Nie, Jing Zhang, Xue Fang, Hongmei Luo, Chuanhai Fu, Zhiyi Wei, Ai-Hui Tang
    2025, 20 (1):  209-223.  doi: 10.4103/1673-5374.391301
    Abstract ( 112 )   PDF (5381KB) ( 35 )   Save
    Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory. Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1; however, whether KIF21A modulates dendritic structure and function in neurons remains unknown. In this study, we found that KIF21A was distributed in a subset of dendritic spines, and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines. Furthermore, the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity. Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching, and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1, but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1. Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’ cognitive abilities. Taken together, our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.
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    Small extracellular vesicles derived from cerebral endothelial cells with elevated microRNA 27a promote ischemic stroke recovery
    Yi Zhang, Zhongwu Liu, Michael Chopp, Michael Millman, Yanfeng Li, Pasquale Cepparulo, Amy Kemper, Chao Li, Li Zhang, Zheng Gang Zhang
    2025, 20 (1):  224-233.  doi: 10.4103/NRR.NRR-D-22-01292
    Abstract ( 96 )   PDF (3468KB) ( 71 )   Save
    Axonal remodeling is a critical aspect of ischemic brain repair processes and contributes to spontaneous functional recovery. Our previous in vitro study demonstrated that exosomes/small extracellular vesicles (sEVs) isolated from cerebral endothelial cells (CEC-sEVs) of ischemic brain promote axonal growth of embryonic cortical neurons and that microRNA 27a (miR-27a) is an elevated miRNA in ischemic CEC-sEVs. In the present study, we investigated whether normal CEC-sEVs engineered to enrich their levels of miR-27a (27a-sEVs) further enhance axonal growth and improve neurological outcomes after ischemic stroke when compared with treatment with non-engineered CEC-sEVs. 27a-sEVs were isolated from the conditioned medium of healthy mouse CECs transfected with a lentiviral miR-27a expression vector. Small EVs isolated from CECs transfected with a scramble vector (Scra-sEVs) were used as a control. Adult male mice were subjected to permanent middle cerebral artery occlusion and then were randomly treated with 27a-sEVs or Scra-sEVs. An array of behavior assays was used to measure neurological function. Compared with treatment of ischemic stroke with Scra-sEVs, treatment with 27a-sEVs significantly augmented axons and spines in the peri-infarct zone and in the corticospinal tract of the spinal grey matter of the denervated side, and significantly improved neurological outcomes. In vitro studies demonstrated that CEC-sEVs carrying reduced miR-27a abolished 27a-sEV-augmented axonal growth. Ultrastructural analysis revealed that 27a-sEVs systemically administered preferentially localized to the pre-synaptic active zone, while quantitative reverse transcription-polymerase chain reaction and Western Blot analysis showed elevated miR-27a, and reduced axonal inhibitory proteins Semaphorin 6A and Ras Homolog Family Member A in the peri-infarct zone. Blockage of the Clathrin-dependent endocytosis pathway substantially reduced neuronal internalization of 27a-sEVs. Our data provide evidence that 27a-sEVs have a therapeutic effect on stroke recovery by promoting axonal remodeling and improving neurological outcomes. Our findings also suggest that suppression of axonal inhibitory proteins such as Semaphorin 6A may contribute to the beneficial effect of 27a-sEVs on axonal remodeling.
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    Early identification of stroke through deep learning with multi-modal human speech and movement data
    ​Zijun Ou, Haitao Wang, Bin Zhang, Haobang Liang, Bei Hu, Longlong Ren, Yanjuan Liu, Yuhu Zhang, Chengbo Dai, Hejun Wu, Weifeng Li, Xin Li
    2025, 20 (1):  234-241.  doi: 10.4103/1673-5374.393103
    Abstract ( 218 )   PDF (2529KB) ( 128 )   Save
    Early identification and treatment of stroke can greatly improve patient outcomes and quality of life. Although clinical tests such as the Cincinnati Pre-hospital Stroke Scale (CPSS) and the Face Arm Speech Test (FAST) are commonly used for stroke screening, accurate administration is dependent on specialized training. In this study, we proposed a novel multimodal deep learning approach, based on the FAST, for assessing suspected stroke patients exhibiting symptoms such as limb weakness, facial paresis, and speech disorders in acute settings. We collected a dataset comprising videos and audio recordings of emergency room patients performing designated limb movements, facial expressions, and speech tests based on the FAST. We compared the constructed deep learning model, which was designed to process multi-modal datasets, with six prior models that achieved good action classification performance, including the I3D, SlowFast, X3D, TPN, TimeSformer, and MViT. We found that the findings of our deep learning model had a higher clinical value compared with the other approaches. Moreover, the multi-modal model outperformed its single-module variants, highlighting the benefit of utilizing multiple types of patient data, such as action videos and speech audio. These results indicate that a multi-modal deep learning model combined with the FAST could greatly improve the accuracy and sensitivity of early stroke identification of stroke, thus providing a practical and powerful tool for assessing stroke patients in an emergency clinical setting.
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    Establishment of human cerebral organoid systems to model early neural development and assess the central neurotoxicity of environmental toxins
    Daiyu Hu, Yuanqing Cao, Chenglin Cai, Guangming Wang, Min Zhou, Luying Peng, Yantao Fan, Qiong Lai, Zhengliang Gao
    2025, 20 (1):  242-252.  doi: 10.4103/NRR.NRR-D-23-00928
    Abstract ( 146 )   PDF (7386KB) ( 68 )   Save
    Human brain development is a complex process, and animal models often have significant limitations. To address this, researchers have developed pluripotent stem cell-derived three-dimensional structures, known as brain-like organoids, to more accurately model early human brain development and disease. To enable more consistent and intuitive reproduction of early brain development, in this study, we incorporated forebrain organoid culture technology into the traditional unguided method of brain organoid culture. This involved embedding organoids in matrigel for only 7 days during the rapid expansion phase of the neural epithelium and then removing them from the matrigel for further cultivation, resulting in a new type of human brain organoid system. This cerebral organoid system replicated the temporospatial characteristics of early human brain development, including neuroepithelium derivation, neural progenitor cell production and maintenance, neuron differentiation and migration, and cortical layer patterning and formation, providing more consistent and reproducible organoids for developmental modeling and toxicology testing. As a proof of concept, we applied the heavy metal cadmium to this newly improved organoid system to test whether it could be used to evaluate the neurotoxicity of environmental toxins. Brain organoids exposed to cadmium for 7 or 14 days manifested severe damage and abnormalities in their neurodevelopmental patterns, including bursts of cortical cell death and premature differentiation. Cadmium exposure caused progressive depletion of neural progenitor cells and loss of organoid integrity, accompanied by compensatory cell proliferation at ectopic locations. The convenience, flexibility, and controllability of this newly developed organoid platform make it a powerful and affordable alternative to animal models for use in neurodevelopmental, neurological, and neurotoxicological studies.
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    AAV mediated carboxyl terminus of Hsp70 interacting protein overexpression mitigates the cognitive and pathological phenotypes of APP/PS1 mice
    Zhengwei Hu, Jing Yang, Shuo Zhang, Mengjie Li, Chunyan Zuo, Chengyuan Mao, Zhongxian Zhang, Mibo Tang, Changhe Shi, Yuming Xu
    2025, 20 (1):  253-264.  doi: 10.4103/NRR.NRR-D-23-01277
    Abstract ( 120 )   PDF (16230KB) ( 73 )   Save
    The E3 ubiquitin ligase, carboxyl terminus of heat shock protein 70 (Hsp70) interacting protein (CHIP), also functions as a co-chaperone and plays a crucial role in the protein quality control system. In this study, we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease. We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain. CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests, reduced amyloid-β plaques, and decreased the expression of both amyloid-β and phosphorylated tau. CHIP also alleviated the concentration of microglia and astrocytes around plaques. In APP/PS1 mice of a younger age, CHIP overexpression promoted an increase in ADAM10 expression and inhibited β-site APP cleaving enzyme 1, insulin degrading enzyme, and neprilysin expression. Levels of HSP70 and HSP40, which have functional relevance to CHIP, were also increased. Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated, which may also reflect a potential mechanism for the neuroprotective effect of CHIP. Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice. Indeed, overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.
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    Drosophila models used to simulate human ATP1A1 gene mutations that cause Charcot-Marie-Tooth type 2 disease and refractory seizures
    Yao Yuan, Lingqi Yu, Xudong Zhuang, Dongjing Wen, Jin He, Jingmei Hong, Jiayu Xie, Shengan Ling, Xiaoyue Du, Wenfeng Chen, Xinrui Wang
    2025, 20 (1):  265-276.  doi: 10.4103/1673-5374.391302
    Abstract ( 112 )   PDF (3641KB) ( 59 )   Save
    Certain amino acids changes in the human Na+/K+-ATPase pump, ATPase Na+/K+ transporting subunit alpha 1 (ATP1A1), cause Charcot-Marie-Tooth disease type 2 (CMT2) disease and refractory seizures. To develop in vivo models to study the role of Na+/K+-ATPase in these diseases, we modified the Drosophila gene homolog, Atpα, to mimic the human ATP1A1 gene mutations that cause CMT2. Mutations located within the helical linker region of human ATP1A1 (I592T, A597T, P600T, and D601F) were simultaneously introduced into endogenous Drosophila Atpα by CRISPR/Cas9-mediated genome editing, generating the AtpαTTTF model. In addition, the same strategy was used to generate the corresponding single point mutations in flies (AtpαI571T, AtpαA576T, AtpαP579T, and AtpαD580F). Moreover, a deletion mutation (Atpαmut) that causes premature termination of translation was generated as a positive control. Of these alleles, we found two that could be maintained as homozygotes (AtpαI571T and AtpαP579T). Three alleles (AtpαA576T, AtpαP579 and AtpαD580F) can form heterozygotes with the Atpαmut allele. We found that the Atpα allele carrying these CMT2-associated mutations showed differential phenotypes in Drosophila. Flies heterozygous for AtpαTTTF mutations have motor performance defects, a reduced lifespan, seizures, and an abnormal neuronal morphology. These Drosophila models will provide a new platform for studying the function and regulation of the sodium-potassium pump.
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    miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow–derived neural crest cells
    Meng Cong, Jing-Jing Hu, Yan Yu, Xiao-Li Li, Xiao-Ting Sun, Li-Ting Wang, Xia Wu, Ling-Jie Zhu, Xiao-Jia Yang, Qian-Ru He, Fei Ding, Hai-Yan Shi
    2025, 20 (1):  277-290.  doi: 10.4103/1673-5374.390956
    Abstract ( 170 )   PDF (8444KB) ( 24 )   Save
    Our previous study found that rat bone marrow–derived neural crest cells (acting as Schwann cell progenitors) have the potential to promote long-distance nerve repair. Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication. Nevertheless, the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear. To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves, we collected conditioned culture medium from hypoxia-pretreated neural crest cells, and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation. The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells. We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells. Subsequently, to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons, we used a microfluidic axonal dissociation model of sensory neurons in vitro, and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons, which was greatly dependent on loaded miR-21-5p. Finally, we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb, as well as muscle tissue morphology of the hind limbs, were obviously restored. These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p. miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome. This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves, and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.
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    A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair
    Simeon C. Daeschler, Katelyn J.W. So, Konstantin Feinberg, Marina Manoraj, Jenny Cheung, Jennifer Zhang, Kaveh Mirmoeini, J. Paul Santerre, Tessa Gordon, Gregory H. Borschel
    2025, 20 (1):  291-304.  doi: 10.4103/NRR.NRR-D-22-01198
    Abstract ( 91 )   PDF (6945KB) ( 11 )   Save
    Axonal regeneration following surgical nerve repair is slow and often incomplete, resulting in poor functional recovery which sometimes contributes to lifelong disability. Currently, there are no FDA-approved therapies available to promote nerve regeneration. Tacrolimus accelerates axonal regeneration, but systemic side effects presently outweigh its potential benefits for peripheral nerve surgery. The authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site, with suitable properties for scalable production and clinical application, aiming to promote nerve regeneration and functional recovery with minimal systemic drug exposure. Tacrolimus is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 days. Size and drug loading are adjustable for applications in small and large caliber nerves, and the wrap degrades within 120 days into biocompatible byproducts. Tacrolimus released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80% compared with systemic delivery. Given its surgical suitability and preclinical efficacy and safety, this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.
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