Advancing cell therapy for neurodegenerative diseases

Mesenchymal stem cell-derived small extracellular vesicles enhance the therapeutic effect of retinal progenitor cells in retinal degenerative disease rats

JOURNAL/nrgr/04.03/01300535-202602000-00050/figure1/v/2025-05-05T160104Z/r/image-tiff Our previous study demonstrated that combined transplantation of bone marrow mesenchymal stem cells and retinal progenitor cells in rats has therapeutic effects on retinal degeneration that are superior to transplantation of retinal progenitor cells alone. Bone marrow mesenchymal stem cells regulate and interact with various cells in the retinal microenvironment by secreting neurotrophic factors and extracellular vesicles. Small extracellular vesicles derived from bone marrow mesenchymal stem cells, which offer low immunogenicity, minimal tumorigenic risk, and ease of transportation, have been utilized in the treatment of various neurological diseases. These vesicles exhibit various activities, including anti-inflammatory actions, promotion of tissue repair, and immune regulation. Therefore, novel strategies using human retinal progenitor cells combined with bone marrow mesenchymal stem cell-derived small extracellular vesicles may represent an innovation in stem cell therapy for retinal degeneration. In this study, we developed such an approach utilizing retinal progenitor cells combined with bone marrow mesenchymal stem cell-derived small extracellular vesicles to treat retinal degeneration in Royal College of Surgeons rats, a genetic model of retinal degeneration. Our findings revealed that the combination of bone marrow mesenchymal stem cell-derived small extracellular vesicles and retinal progenitor cells significantly improved visual function in these rats. The addition of bone marrow mesenchymal stem cell-derived small extracellular vesicles as adjuvants to stem cell transplantation with retinal progenitor cells enhanced the survival, migration, and differentiation of the exogenous retinal progenitor cells. Concurrently, these small extracellular vesicles inhibited the activation of regional microglia, promoted the migration of transplanted retinal progenitor cells to the inner nuclear layer of the retina, and facilitated their differentiation into photoreceptors and bipolar cells. These findings suggest that bone marrow mesenchymal stem cell-derived small extracellular vesicles potentiate the therapeutic efficacy of retinal progenitor cells in retinal degeneration by promoting their survival and differentiation.

Sox2-overexpressing neural stem cells alleviate ventricular enlargement and neurological dysfunction in posthemorrhagic hydrocephalus

JOURNAL/nrgr/04.03/01300535-202602000-00045/figure1/v/2025-05-05T160104Z/r/image-tiff Neural stem cells (NSCs) have the potential for self-renewal and multidirectional differentiation, and their transplantation has achieved good efficacy in a variety of diseases. However, only 1%-10% of transplanted NSCs survive in the ischemic and hypoxic microenvironment of posthemorrhagic hydrocephalus. Sox2 is an important factor for NSCs to maintain proliferation. Therefore, Sox2-overexpressing NSCs (NSCSox2) may be more successful in improving neurological dysfunction after posthemorrhagic hydrocephalus. In this study, human NSCSox2 was transplanted into a posthemorrhagic hydrocephalus mouse model, and retinoic acid was administered to further promote NSC differentiation. The results showed that NSCSox2 attenuated the ventricular enlargement caused by posthemorrhagic hydrocephalus and improved neurological function. NSCSox2 also promoted nerve regeneration, inhibited neuroinflammation and promoted M2 polarization (anti-inflammatory phenotype), thereby reducing cerebrospinal fluid secretion in choroid plexus. These findings suggest that NSCSox2 rescued ventricular enlargement and neurological dysfunction induced by posthemorrhagic hydrocephalus through neural regeneration and modulation of inflammation.

Promotion of quiescence and maintenance of function of mesenchymal stem cells on substrates with surface potential

The widespread use of human mesenchymal stem cells(hMSCs) is impeded by functional loss during prolonged expansion. Although multiple approaches have been attempted to preserve hMSCs stemness, a suitable culture system remains to be modified. The interaction between electrical signals and stem cells is expected to better maintain the function of stem cells. However, it remains unclear whether the surface potential of substrates has the potential to preserve stem cell function during in vitro expansion. In our study, hMSCs cultured on materials with different surface potentials could be induced into a reversible quiescent state, and we demonstrated that quiescent hMSCs could be reactivated and transitioned back into the proliferation cell cycle. hMSCs cultured under appropriate potential displayed superior differentiation and proliferation abilities within the same generation compared to conventional conditions. These findings underscore the importance of surface potential as a critical physical factor regulating hMSCs stemness. Manipulating the surface potential of hMSCs culture substrates holds promise for optimising preservation and culture conditions, thereby enhancing their application in tissue repair and regeneration engineering.

The impact of Alzheimer's disease on cortical complexity and its underlying biological mechanisms

BACKGROUND

Alzheimer's disease (AD) might impact the complexity of cerebral cortex, and the underlying biological mechanisms responsible for cortical changes in the AD cortex remain unclear.

METHODS

Fifty-eight participants with AD and 67 normal controls underwent high-resolution 3 T structural brain MRI. Using surface-based morphometry (SBM), we created vertex-wise maps for group comparisons in terms of five measures: cortical thickness, fractal dimension, gyrification index, Toro's gyrification index and sulcal depth respectively. Five machine learning (ML) models combining SBM parameters were established to predict AD. In addition, transcription-neuroimaging association analyses, as well as Mendelian randomization of AD and cortical thickness data, were conducted to investigate the genetic mechanisms and biological functions of AD.

RESULTS

AD patients exhibited topological changes in cortical complexity, with increased complexity in the frontal and temporal cortex and decreased complexity in the insula cortex, alongside extensive cortical atrophy. Combining different SBM measures could aid disease diagnosis. The genes involved in cell structure support and the immune response were the strongest contributors to cortical anatomical features in AD patients. The identified genes associated with AD cortical morphology were overexpressed or underexpressed in excitatory neurons, oligodendrocytes, and astrocytes.

CONCLUSION

Complexity alterations of the cerebral surface may be associated with a range of biological processes and molecular mechanisms, including immune responses. The present findings may contribute to a more comprehensive understanding of brain morphological patterns in AD patients.

Targeting mitochondria with natural polyphenols for treating Neurodegenerative Diseases: a comprehensive scoping review from oxidative stress perspective

Neurodegenerative diseases are a class of conditions with widespread detrimental impacts, currently lacking effective therapeutic drugs. Recent studies have identified mitochondrial dysfunction and the resultant oxidative stress as crucial contributors to the pathogenesis of neurodegenerative diseases. Polyphenols, naturally occurring compounds with inherent antioxidant properties, have demonstrated the potential to target mitochondria and mitigate oxidative stress. This therapeutic potential has garnered significant attention in recent years. Investigating the mitochondrial targeting capacity of polyphenols, their role in functional regulation, and their ability to modulate oxidative stress, along with exploring novel technologies and strategies for modifying polyphenol compounds and their formulations, holds promise for providing new avenues for the treatment of neurodegenerative diseases.

A targeted approach: Gene and RNA editing for neurodegenerative disease treatment

With the global aging trend, neurodegenerative diseases (NDs) have emerged as a significant public health concern in the 21st century, imposing substantial economic burdens on families and society. NDs are characterized by cognitive and motor decline, resulting from a combination of genetic and environmental factors. Currently, there is no cure for NDs. Gene and RNA editing therapies offer new possibilities for addressing NDs. Gene editing involves modifying mutant genes associated with NDs, while RNA editing can directly modify RNA molecules to regulate the protein translation process, potentially influencing the expression of genes related to NDs. In this review, we examined the historical evolution, mechanisms of action, applications in NDs, advantages and disadvantages, as well as ethical and safety considerations of gene and RNA editing. While gene and RNA editing technologies hold promise for treating NDs, further research and development are needed to address safety, efficacy, and treatment timing issues, ultimately offering improved treatment options for ND patients. Our review provides valuable insights for future gene and RNA editing applications in ND treatment.

Association of red blood cell count, hemoglobin concentration, and inflammatory indices with cognitive impairment severity in Alzheimer's disease

Some studies have found that patients with Alzheimer's disease (AD) have changes in levels of red blood cell (RBC) and hemoglobin (HB), and some inflammatory indexes are increased. However, the results of relevant studies are not uniform. The aim of this study is to investigate the changes of RBC, HB, and commonly used inflammatory indexes in patients with AD and their correlation with the severity of cognitive impairment. A total of 225 subjects with AD and 2000 healthy controls were included. Dementia severity was evaluated by Mini-Mental State Examination (MMSE). The RBC count and HB concentration of subjects were detected, and inflammatory indexes including neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR), systemic immune inflammation index (SII), systemic inflammation response index (SIRI), and pan-immune-inflammation value (PIV) were calculated. RBC count, HB concentration, NLR, PLR, MLR were independent influencing factors for AD. RBC count and HB concentration are significantly associated with the severity of cognitive impairment in AD patients. RBC count has a significant effect on the severity of cognitive impairment without considering the education level, but their effects on the severity of cognitive impairment are no longer significant when the education level is considered. The RBC count and HB concentration of AD patients are decreased, and are correlated with the severity of cognitive impairment. In addition, some inflammatory indexes are associated with the risk of AD.

Optimal Production of 3D Neuronal Lineage Population by Morphological Classification

BACKGROUND

The increasing prevalence of neurodegenerative diseases and toxic substance exposure highlights the need for neuronal cell models that closely mimic human neurons in vivo. Compared to traditional models, human pluripotent stem cell (hPSC)-derived three-dimensional models mimic human physiological characteristics and complex nervous system interactions. These models enable patient-specific treatments and improve the predictive accuracy of drug toxicity evaluations. However, differentiation efficiency varies based on organoid size, structure, and cell line characteristics, necessitating standardized protocols for consistent outcome.

METHODS

The morphological characteristics of hPSC-derived embryonic bodies (EBs) formed by concave microwells were analyzed at the early stage of neuronal differentiation. Criteria were established to identify cells with high differentiation efficiency, enabling the optimization of differentiation methods applicable across various cell lines. Neuronal organoids were generated using a microfluidic-concave chip, and their suitability for drug toxicity testing was assessed.

RESULTS

EBs, formed in 500 µm concave microwells, exhibited the highest efficiency for neuronal cell differentiation. Cavity-like EBs were more suitable for neuronal differentiation and maturation than cystic-like forms. The optimal neuronal lineage differentiation method was established, and the drug toxicity sensitivity of organoids generated from this method was validated.

CONCLUSIONS

This study identified EB structures suitable for neuronal lineage differentiation based on morphological classification. Furthermore, this study suggested an optimal method for generating neuronal organoids. This method can be applied to various cell lines, enabling its precise use in patient-specific treatments and drug toxicity tests.

High-Efficiency Ocular Delivery of Brain-Derived Neurotrophic Factor and Oligomycin for Neuroprotection in Glaucoma

Glaucoma is a retinal neurodegenerative disease characterized by progressive apoptosis of retinal ganglion cells (RGCs) and irreversible visual impairment. Current therapies rarely offer direct protection for RGCs, highlighting the need for new neuroprotective approaches. Although viral delivery of brain-derived neurotrophic factor (BDNF) has shown potential, concerns about retinal inflammation and limited applicability persist. Meanwhile, non-viral vectors remain inefficient for in vivo ocular gene delivery. Here, a highly biocompatible nanoplatform-PBAE-PLGA-Oligomycin-pBDNF nanoparticles (PPOB NPs) is reported-that co-delivers oligomycin (an ATP inhibitor) and a BDNF plasmid to Müller cells in vivo. This nanoplatform attains an unprecedented transfection efficiency of 64.26% in Müller cells, thereby overcoming the limitations of monotherapeutic neurotrophic approaches that fail to inhibit ATP overproduction and attendant inflammatory responses. In a chronic ocular hypertension rat model, oligomycin effectively mitigated RGC damage by suppressing Müller cell hyperactivation and excessive ATP production under elevated intraocular pressure. Concurrently, it synergistically enhanced BDNF expression in Müller cells, achieving robust protection of RGCs and preservation of optic nerve function. These findings underscore the promise of PPOB NPs as a dual-functional platform, featuring high biocompatibility and efficient gene delivery, for multifaceted therapies against glaucoma and other ocular diseases.

Near-infrared fluorescent nanoprobe enables noninvasive, longitudinal monitoring of graft outcome in RPE transplantation

Objectives

Retinal pigment epithelium (RPE) cell transplantation holds therapeutic promise for retinal degenerative diseases, but longitudinal monitoring of graft survival and efficacy remains clinically challenging. The aim of this study is to develop a simple and effective method for the therapeutic quantification of RPE cell transplantation and immune rejection in vivo.

Methods

A nanoprobe was developed and modified to label donor RPE cells, and used to monitor the position and intensity of the fluorescence signal in vivo. Immunofluorescence staining and single-cell RNA sequencing (scRNA-seq) were used to characterize the cell types showing the fluorescence signal of the nanoprobe and to determine the composition of the immune microenvironment associated with subretinal transplantation.

Results

The spatial distribution of the fluorescence signal of the nanoprobe corresponded with the site of transplantation, but the signal intensity decreased over time, while the signal distribution extended to the choroid. Additionally, the nanoprobe fluorescence signal was detected in the liver and spleen during long-term monitoring. Conversely, in mice administered the immunosuppressive drug cyclosporine A, the decrease in signal intensity was slower and the expansion of the signal distribution was less pronounced. Immunofluorescence analysis revealed a significant temporal increase in the proportion of macrophages with nanoprobe-labeled cells following transplantation. The stability and cell-penetrating ability of the nanoprobe enables the labeling of immune cell niches in RPE transplantation. Additionally, scRNA-seq analysis of nanoprobe-labeled cells identified MDK and ANXA1 signaling pathway in donor RPE cells as initiators of the immune rejection cascade, which were further amplified by macrophage-mediated pro-inflammatory signaling.

Conclusion

Near-infrared fluorescent nanoprobes represent a reliable method for in vivo tracing of donor RPE cells and long-term observation of nanoprobe distribution can be used to evaluate the degree of immune rejection. Molecular analysis of nanoprobe-labeled cells facilitates the characterization of the dynamic immune cell rejection niche and the landscape of donor-host interactions in RPE transplantation.

Microfluidics-Based Microcarriers for Live-Cell Delivery

Live-cell therapy has emerged as a revolutionary treatment modality, providing a novel therapeutic avenue for intractable diseases. However, a major challenge in live-cell therapy is to maintain live-cell viability and efficacy during the treatment. Microcarriers are crucial for enhancing cell retention, viability, and functions by providing a protective scaffold and creating a supportive environment for live-cell proliferation and metabolism. For microcarrier construction, the microfluidic technology demonstrates excellent characteristics in terms of controllability over microcarrier size and morphology as well as potential for high-throughput production. To date, multiple live-cell delivery microcarrier types (e.g., microspheres, microfibers, and microneedles) are prepared via microfluidic liquid templates to meet different therapeutic needs. In this review, recent developments in microfluidics-based microcarriers for live-cell delivery are presented. It is focused on categorizing the structural design of microfluidic-derived cell-laden microcarriers, and summarizing various therapeutic applications. Finally, an outlook is provided on the future challenges and opportunities in this field.

Current Applications of Human Pluripotent Stem Cells in Neuroscience Research and Cell Transplantation Therapy for Neurological Disorders

Many neurological diseases involving tissue damage cannot be treated with drug-based approaches, and the inaccessibility of human brain samples further hampers the study of these diseases. Human pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), provide an excellent model for studying neural development and function. PSCs can be differentiated into various neural cell types, providing a renewal source of functional human brain cells. Therefore, PSC-derived neural cells are increasingly used for multiple applications, including neurodevelopmental and neurotoxicological studies, neurological disease modeling, drug screening, and regenerative medicine. In addition, the neural cells generated from patient iPSCs can be used to study patient-specific disease signatures and progression. With the recent advances in genome editing technologies, it is possible to remove the disease-related mutations in the patient iPSCs to generate corrected iPSCs. The corrected iPSCs can differentiate into neural cells with normal physiological functions, which can be used for autologous transplantation. This review highlights the current progress in using PSCs to understand the fundamental principles of human neurodevelopment and dissect the molecular mechanisms of neurological diseases. This knowledge can be applied to develop better drugs and explore cell therapy options. We also discuss the basic requirements for developing cell transplantation therapies for neurological disorders and the current status of the ongoing clinical trials.

Advantages and challenges of using allogeneic vs. autologous sources for neuronal cell replacement in Parkinson's disease: Insights from non-human primate studies

Intracerebral grafting of dopamine-producing cells is proposed as a strategy to replace the typical neurons lost to Parkinson's disease (PD) and improve PD motor symptoms. Non-human primate studies have provided clues on the relationship between the host's immune response and grafting success. Herein, we discuss how the host's immune system differentially affects the graft depending on the origin of the cells and reflect on the advantages and limitations of the immune paradigms utilized to assess graft-related outcomes. We also consider new strategies to minimize or circumvent the host's immunological response and related preclinical research needed to identify the most promising new approaches to be translated into the clinic.

A Review on the Stability Challenges of Advanced Biologic Therapeutics

Advanced biotherapeutic systems such as gene therapy, mRNA lipid nanoparticles, antibody-drug conjugates, fusion proteins, and cell therapy have proven to be promising platforms for delivering targeted biologic therapeutics. Preserving the intrinsic stability of these advanced therapeutics is essential to maintain their innate structure, functionality, and shelf life. Nevertheless, various challenges and obstacles arise during formulation development and throughout the storage period due to their complex nature and sensitivity to various stress factors. Key stability concerns include physical degradation and chemical instability due to various factors such as fluctuations in pH and temperature, which results in conformational and colloidal instabilities of the biologics, adversely affecting their quality and therapeutic efficacy. This review emphasizes key stability issues associated with these advanced biotherapeutic systems and approaches to identify and overcome them. In gene therapy, the brittleness of viral vectors and gene encapsulation limits their stability, requiring the use of stabilizers, excipients, and lyophilization. Keeping cells viable throughout the whole cell therapy process, from culture to final formulation, is still a major difficulty. In mRNA therapeutics, stabilization strategies such as the optimization of mRNA nucleotides and lipid compositions are used to address the instability of both the mRNA and lipid nanoparticles. Monoclonal antibodies are colloidally and conformationally unstable. Hence, buffers and stabilizers are useful to maintain stability. Although fusion proteins and monoclonal antibodies share structural similarities, they show a similar pattern of instability. Antibody-drug conjugates possess issues with conjugation and linker stability. This review outlines the stability issues associated with advanced biotherapeutics and provides insights into the approaches to address these challenges.

Targeting neurodegenerative disease-associated protein aggregation with proximity-inducing modalities

Neurodegenerative diseases (NDDs) are characterized by progressive neuronal dysfunction and anatomical changes caused by neuron loss and gliosis, ultimately leading to severe declines in brain function. While these disorders arise from a variety of pathological mechanisms, a common molecular feature is the accumulation of misfolded proteins, which occurs both inside and outside neurons. For example, Alzheimer's disease (AD) is defined by extracellular β-amyloid plaques and intracellular tau neurofibrillary tangles. These pathological protein aggregates are often resistant to traditional small molecule drugs. Recent advances in proximity-inducing chimeras such as proteolysis-targeting chimeras (PROTACs), lysosome-targeting chimeras (LYTACs), autophagy-targeted chimeras (AUTOTACs), dephosphorylation-targeting chimeras (DEPTACs) and ribonuclease-targeting chimeras (RIBOTACs) offer promising strategies to eliminate pathological proteins or mRNAs through intracellular degradation pathways. These innovative approaches open avenues for developing new therapies for NDDs. In this review we summarize the regulatory mechanisms of protein aggregation, highlight the advancements in proximity-inducing modalities for NDDs, and discuss the current challenges and future directions in therapeutic development.

Progress and challenges in developing allogeneic cell therapies

The new era of cell therapeutics has started with autologous products to avoid immune rejection. However, therapeutics derived from allogeneic cells could be scaled and made available for a much larger patient population if immune rejection could reliably be overcome. In this review, we outline gene engineering concepts aimed at generating immune-evasive cells. First, we summarize the current state of allogeneic immune cell therapies, and second, we compile the still limited data for allogeneic cell replacement therapies. We emphasize the advances in this fast-developing field and provide an optimistic outlook for future allogeneic cell therapies.

Advances in clinical translation of stem cell-based therapy in neurological diseases

Stem cell-based therapies have raised considerable interest to develop regenerative treatment for neurological disorders with high disability. In this review, we focus on recent preclinical and clinical evidence of stem cell therapy in the treatment of degenerative neurological diseases and discuss different cell types, delivery routes and biodistribution of stem cell therapy. In addition, recent advances of mechanistic insights of stem cell therapy, including functional replacement by exogenous cells, immunomodulation and paracrine effects of stem cell therapies are also demonstrated. Finally, we also highlight the adjunction approaches that has been implemented to augment their reparative function, survival and migration to target specific tissue, including stem cell preconditioning, genetical engineering, co-transplantation and combined therapy.

Overview of Metformin and Neurodegeneration: A Comprehensive Review

This comprehensive review examines the therapeutic potential of metformin, a well-established diabetes medication, in treating neurodegenerative disorders. Originally used as a first-line treatment for type 2 diabetes, recent studies have begun investigating metformin's effects beyond metabolic disorders, particularly its neuroprotective capabilities against conditions like Parkinson's disease, Alzheimer's disease, Huntington's disease, and multiple sclerosis. Key findings demonstrate that metformin's neuroprotective effects operate through multiple pathways: AMPK activation enhancing cellular energy metabolism and autophagy; upregulation of antioxidant defenses; suppression of inflammation; inhibition of protein aggregation; and improvement of mitochondrial function. These mechanisms collectively address common pathological features in neurodegeneration and neuroinflammation, including oxidative stress, protein accumulation, and mitochondrial dysfunction. Clinical and preclinical evidence supporting metformin's association with improved cognitive performance, reduced risk of dementia, and modulation of pathological hallmarks of neurodegenerative diseases is critically evaluated. While metformin shows promise as a therapeutic agent, this review emphasizes the need for further investigation to fully understand its mechanisms and optimal therapeutic applications in neurodegenerative diseases.

Recent Advances in Aging and Immunosenescence: Mechanisms and Therapeutic Strategies

Cellular senescence is an irreversible state of cell cycle arrest. Senescent cells (SCs) accumulate in the body with age and secrete harmful substances known as the senescence-associated secretory phenotype (SASP), causing chronic inflammation; at the same time, chronic inflammation leads to a decrease in immune system function, known as immunosenescence, which further accelerates the aging process. Cellular senescence and immunosenescence are closely related to a variety of chronic diseases, including cardiovascular diseases, metabolic disorders, autoimmune diseases, and neurodegenerative diseases. Studying the mechanisms of cellular senescence and immunosenescence and developing targeted interventions are crucial for improving the immune function and quality of life of elderly people. Here, we review a series of recent studies focusing on the molecular mechanisms of cellular senescence and immunosenescence, the regulation of aging by the immune system, and the latest advances in basic and clinical research on senolytics. We summarize the cellular and animal models related to aging research, as well as the mechanisms, strategies, and future directions of aging interventions from an immunological perspective, with the hope of laying the foundation for developing novel and practical anti-aging therapies.

Hypoxia-preconditioned human dental pulp stem cells transplantation alleviates hypoxic-ischemic brain damage via STAT3/NLRP3/Caspase-1 axis in neonatal rats

This study was conducted to examine the effects and mechanisms of hypoxia-preconditioned human dental pulp stem cells (H-hDPSCs) transplantation on microglial pyroptosis in neonatal rats with hypoxic-ischemic brain damage (HIBD). The hDPSCs were extracted using the tissue block method and identified by immunofluorescence staining. The HIBD model was constructed using the classical Rice-Vannucci method. 24 h after HIBD, normoxic preconditioning hDPSCs (N-hDPSCs) and H-hDPSCs were transplanted into the lateral ventricle. The brain damage was examined by hematoxylin & eosin and Nissl stainings 72 h after transplantation. The expression of signal transducer and activator of transcription 3 (STAT3)/NOD-like receptor family pyrin domain-containing 3 (NLRP3)/Caspase-1 axis-related proteins was analyzed by immunofluorescence staining and western blots. Tissue levels of interleukin-1 beta (IL-1β) were derived from ELISA. After modeling, the neural cells in the HIBD group were disordered and sparsely scattered, with a deficiency of nitrosamines. The data revealed that the phosphorylated STAT3, NLRP3, Cleaved-Caspase 1, N-terminal fragment of gasdermin D (GSDMD-N), and IL-1β protein expression were significantly lower in the H-hDPSCs and N-hDPSCs groups compared to the HIBD group. The protein expression in the H-hDPSCs group was considerably lower than in the N-hDPSCs group. H-hDPSCs may protect microglia from pyroptosis by regulating the STAT3/NLRP3/Caspase-1/GSDMD axis to alleviate inflammatory damage, and attenuate HIBD in newborn rats at the same time. Moreover, the therapeutic effect of H-hDPSCs transplantation was superior to that of N-hDPSCs transplantation.

Indole-3-Propionic Acid Attenuates Neuroinflammation and Cognitive Deficits by Inhibiting the RAGE-JAK2-STAT3 Signaling Pathway

Cognitive disorders such as Alzheimer's disease (AD) are highly prevalent and place heavy burdens on society. Neuroinflammation is a driver of cognitive impairment, with no effective drugs. Indole 3-propionic acid (IPA) is a tryptophan metabolite mainly produced byClostridium sporogenes, which exhibits multiple functions, including antioxidant, anti-inflammatory, antiaging, and neuroprotective properties. However, the restorative effects and molecular mechanisms of IPA in cognitive impairment remain to be investigated. In this study, we found that IPA reduced LPS-induced apoptosis and oxidative damage in HT22 cells and decreased LPS-induced inflammation in BV2 cells. Besides, IPA promoted neurogenesis, inhibited glial cell activation, maintained the integrity of the BBB and intestinal barrier, and remodeled the gut microbiota, thereby alleviating memory impairment in LPS-induced cognitively impaired mice. At the mechanistic level, IPA inhibited the RAGE-JAK2-STAT3 signaling pathway and thus ameliorated neuroinflammation. Interestingly, Colivelin TFA, an activator of JAK2-STAT3 signaling, partially reversed the neurorestorative effects of IPA. In conclusion, IPA ameliorates neuroinflammation and cognitive deficits via the inhibition of the RAGE-JAK2-STAT3 signaling pathway. Thus, IPA may be a potential drug for the treatment of cognitive disorders.

Chiral Inorganic Nanomaterial-Based Diagnosis and Treatments for Neurodegenerative Diseases

Chiral nanomaterials are widely investigated over recent decades due to their biocompatibility and unique chiral effects. These key properties have significantly promoted the rapid development of chiral nanomaterials in bioengineering and medicine. In this review, the basic principles of constructing chiral nanomaterials along with the latest progress in research are comprehensively summarized. Then, the application of chiral nanomaterials for the diagnosis of neurodegenerative diseases (NDDs) is systematically described. In addition, the significant potential and broad prospects of chiral nanomaterials in the treatment of NDDs are highlighted from several aspects, including the disaggregation of neurofibrils, the scavenging of reactive oxygen species, regulation of the microbial-gut-brain axis, the elimination of senescent cells, and the promotion of directed differentiation in neural stem cells. Finally, a perspective of the challenges and future development of chiral nanomaterials for the treatment of NDDs is provided.

Postnatal development of rat retina: a continuous observation and comparison between the organotypic retinal explant model and in vivo development

JOURNAL/nrgr/04.03/01300535-202503000-00033/figure1/v/2024-06-17T092413Z/r/image-tiff The organotypic retinal explant culture has been established for more than a decade and offers a range of unique advantages compared with in vivo experiments and cell cultures. However, the lack of systematic and continuous comparison between in vivo retinal development and the organotypic retinal explant culture makes this model controversial in postnatal retinal development studies. Thus, we aimed to verify the feasibility of using this model for postnatal retinal development studies by comparing it with the in vivo retina. In this study, we showed that postnatal retinal explants undergo normal development, and exhibit a consistent structure and timeline with retinas in vivo. Initially, we used SOX2 and PAX6 immunostaining to identify retinal progenitor cells. We then examined cell proliferation and migration by immunostaining with Ki-67 and doublecortin, respectively. Ki-67- and doublecortin-positive cells decreased in both in vivo and explants during postnatal retinogenesis, and exhibited a high degree of similarity in abundance and distribution between groups. Additionally, we used Ceh-10 homeodomain-containing homolog, glutamate-ammonia ligase (glutamine synthetase), neuronal nuclei, and ionized calcium-binding adapter molecule 1 immunostaining to examine the emergence of bipolar cells, Müller glia, mature neurons, and microglia, respectively. The timing and spatial patterns of the emergence of these cell types were remarkably consistent between in vivo and explant retinas. Our study showed that the organotypic retinal explant culture model had a high degree of consistency with the progression of in vivo early postnatal retina development. The findings confirm the accuracy and credibility of this model and support its use for long-term, systematic, and continuous observation.

CircFUNDC1 interacts with CDK9 to promote mitophagy in nucleus pulposus cells under oxidative stress and ameliorates intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is a leading cause of low back pain, with limited effective treatments due to an incomplete understanding of disease mechanisms. In this study, we report that circFUNDC1, a nuclear circular RNA, is markedly downregulated in nucleus pulposus cells (NPCs) from patients with end-stage IVDD. CircFUNDC1 is derived from the gene encoding the FUN14 domain-containing 1 (FUNDC1) protein, which is essential for mitophagy and cell survival. Functional analyses reveal that circFUNDC1 plays a crucial role in maintaining extracellular matrix homeostasis by enhancing the expression of anabolic factors in NPCs. Additionally, we identified the transcriptional regulator cyclin-dependent kinase 9 (CDK9) as a novel binding partner for circFUNDC1. Binding with circFUNDC1 recruits CDK9 via complementary nucleotides to the FUNDC1 promoter to stimulate the production of full-length FUNDC1 mRNAs and proteins, forming a positive feedback loop. Overexpression of circFUNDC1 protects NPCs from oxidative stress by promoting mitophagy, reducing reactive oxygen species levels, and inhibiting cellular senescence. Moreover, circFUNDC1 overexpression delays the onset of IVDD in an ex-vivo culture model. This study is the first to demonstrate that circFUNDC1 is vital for protecting NPCs from oxidative stress, suggesting circFUNDC1 as a potential therapeutic target for IVDD.

Peripheral proteinopathy in neurodegenerative diseases

Proteinopathies in neurology typically refer to pathological changes in proteins associated with neurological diseases, such as the aggregation of amyloid β and Tau in Alzheimer's disease, α-synuclein in Parkinson's disease and multiple system atrophy, and TAR DNA-binding protein 43 in amyotrophic lateral sclerosis and frontotemporal dementia. Interestingly, these proteins are also commonly found in peripheral tissues, raising important questions about their roles in neurological disorders. Multiple studies have shown that peripherally derived pathological proteins not only travel to the brain through various routes, aggravating brain pathology, but also contribute significantly to peripheral dysfunction, highlighting their crucial impact on neurological diseases. Investigating how these peripherally derived proteins influence the progression of neurological disorders could open new horizons for achieving early diagnosis and treatment. This review summarizes the distribution, transportation pathways, and pathogenic mechanisms of several neurodegenerative disease-related pathological proteins in the periphery, proposing that targeting these peripheral pathological proteins could be a promising strategy for preventing and managing neurological diseases.

Targeting Shp2 as a therapeutic strategy for neurodegenerative diseases

The incidence of neurodegenerative diseases (NDs) has increased recently. However, most of the current governance strategies are palliative and lack effective therapeutic drugs. Therefore, elucidating the pathological mechanism of NDs is the key to the development of targeted drugs. As a member of the tyrosine phosphatase family, the role of Shp2 has been studied in tumors, but the research in the nervous system is still in a sporadic state. It can be phosphorylated by tyrosine kinases and then positively regulate tyrosine kinase-dependent signaling pathways. It could also be used as an adaptor protein to mediate downstream signaling pathways. Most of the existing studies have shown that Shp2 may be a potential molecular "checkpoint" against NDs, but its role in promoting degenerative lesions is difficult to ignore as well, and its two-way effect of both activation and inhibition is very distinctive. Shp2 is closely related to NDs-related pathogenic factors such as oxidative stress, mitochondrial dysfunction, excitatory toxicity, immune inflammation, apoptosis, and autophagy. Its bidirectional effects interfere with these pathogenic factors, making it a core component of the feedback and crosstalk network between multiple signaling pathways. Therefore, this article reviews the molecular mechanism of Shp2 regulation in NDs and its regulatory role in various pathogenic factors, providing evidence for the treatment of NDs by targeting Shp2 and the development of molecular targeted drugs.

Astrocytes in Primary Familial Brain Calcification (PFBC): Emphasis on the Importance of Induced Pluripotent Stem Cell-Derived Human Astrocyte Models

Primary familial brain calcification (PFBC) is a rare, progressive central nervous system (CNS) disorder without a cure, and the current treatment methodologies primarily aim to relieve neurological and psychiatric symptoms of the patients. The disease is characterized by abnormal bilateral calcifications in the brain, however, our mechanistic understanding of the biology of the disease is still limited. Determining the roles of the specific cell types and molecular mechanisms involved in the pathophysiological processes of the disease is of great importance for the development of novel and effective treatment methodologies. There is a growing interest in the involvement of astrocytes in PFBC, as recent studies have suggested that astrocytes play a central role in the disease and that functional defects in these cells are critical for the development and progression of the disease. This review aims to discuss recent findings on the roles of astrocytes in PFBC pathophysiology, with a focus on known expression and roles of PFBC genes in astrocytes. Additionally, we discuss the importance of human astrocytes for PFBC disease modeling, and astrocytes as a potential therapeutic target in PFBC. Utilization of species-specific and physiologically relevant PFBC model systems can open new avenues for basic research, drug development, and regenerative medicine.

Robot-Assisted Stereotactic Microinjection Method for Precision Cell Transplantation in Rat and Canine Models

Cell transplantation is a promising approach for addressing neurodegenerative conditions. In this study, we developed a robot-assisted stereotactic microinjection system for transplanting cells. We evaluated the factors that affect cellular graft viability and other properties, including the gauge of the syringe needle and the injection rate. We systematically compared the synchronous withdrawal injection (SWI) and fixed-point injection (FPI) procedures in agarose and rat brain models. In vitro assessments revealed superior dye dispersion with SWI compared to FPI, and in vivo analyses confirmed that SWI reduced the tissue injury and improved cell distribution in the striatum. We applied this robot-assisted technique to evaluate the accuracy and safety of cell transplantation in canine models. Overall, this strategy enhances the accuracy and safety of graft delivery, potentially improving outcomes and advancing therapeutic strategies for the clinical treatment of neurodegenerative disorders.

Understanding the Molecular Impact of Physical Exercise on Alzheimer's Disease

Alzheimer's disease is one of the most common neurodegenerative diseases, characterized by a wide range of neurological symptoms that begin with personality changes and psychiatric symptoms, progress to mild cognitive impairment, and eventually lead to dementia. Physical exercise is part of the non-pharmacological treatments used in Alzheimer's disease, as it has been shown to delay the neurodegenerative process by improving the redox state in brain tissue, providing anti-inflammatory effects or stimulating the release of the brain-derived neurotrophic factor that enhances the brain structure and cognitive performance. Here, we reviewed the results obtained from studies conducted in both animal models and human subjects to comprehend how physical exercise interventions can exert changes in the molecular mechanisms underlying the pathophysiological processes in Alzheimer's disease: amyloid β-peptide pathology, tau pathology, neuroglial changes, mitochondrial dysfunction, and oxidative stress. Physical exercise seems to have a protective effect against Alzheimer's disease, since it has been shown to induce positive changes in some of the biomarkers related to the pathophysiological processes of the disease. However, additional studies in humans are necessary to address the current lack of conclusive evidence.

The therapeutic potential of glycyrrhizic acid and its metabolites in neurodegenerative diseases: Evidence from animal models

Neurodegenerative diseases, mostly occurring in the elderly population, are the significant cause of disability and death worldwide. The pathogenesis of neurodegenerative diseases is still largely unknown yet, although they have been continuously explored. Thus, there is still a lack of safe, effective, and low side effect drugs in clinical practice for the treatment of neurodegenerative diseases. Pieces of accumulating evidence have demonstrated that licorice played neuroprotective roles in various neurodegenerative diseases. In the past two decades, increasing studies have indicated that glycyrrhizic acid (GL), the main active ingredient from traditional Chinese medicine licorice (widely used in the food industry) and a triterpenoid saponin with multiple pharmacological effects (such as anti-oxidant, anti-inflammatory, and immune regulation), and its metabolites (glycyrrhetinic acid and carbenoxolone) play a neuroprotective role in a range of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease and epilepsy. This review will elaborate on the multiple neuroprotective mechanisms of GL and its metabolites in this series of diseases, aiming to provide a basis for further research on these protective drugs for neurodegenerative diseases and their clinical application. In summary, GL may be a promising candidate drug for the therapy of neurodegenerative diseases.

Multi-omics in exploring the pathophysiology of diabetic retinopathy

Diabetic retinopathy (DR) is a leading global cause of vision impairment, with its prevalence increasing alongside the rising rates of diabetes mellitus (DM). Despite the retina's complex structure, the underlying pathology of DR remains incompletely understood. Single-cell RNA sequencing (scRNA-seq) and recent advancements in multi-omics analyses have revolutionized molecular profiling, enabling high-throughput analysis and comprehensive characterization of complex biological systems. This review highlights the significant contributions of scRNA-seq, in conjunction with other multi-omics technologies, to DR research. Integrated scRNA-seq and transcriptomic analyses have revealed novel insights into DR pathogenesis, including alternative transcription start site events, fluctuations in cell populations, altered gene expression profiles, and critical signaling pathways within retinal cells. Furthermore, by integrating scRNA-seq with genetic association studies and multi-omics analyses, researchers have identified novel biomarkers, susceptibility genes, and potential therapeutic targets for DR, emphasizing the importance of specific retinal cell types in disease progression. The integration of scRNA-seq with metabolomics has also been instrumental in identifying specific metabolites and dysregulated pathways associated with DR. It is highly conceivable that the continued synergy between scRNA-seq and other multi-omics approaches will accelerate the discovery of underlying mechanisms and the development of novel therapeutic interventions for DR.

Generating human neural diversity with a multiplexed morphogen screen in organoids

Morphogens choreograph the generation of remarkable cellular diversity in the developing nervous system. Differentiation of stem cells in vitro often relies upon the combinatorial modulation of these signaling pathways. However, the lack of a systematic approach to understand morphogen-directed differentiation has precluded the generation of many neural cell populations, and the general principles of regional specification and maturation remain incomplete. Here, we developed an arrayed screen of 14 morphogen modulators in human neural organoids cultured for over 70 days. Deconvolution of single-cell-multiplexed RNA sequencing data revealed design principles of brain region specification. We tuned neural subtype diversity to generate a tachykinin 3 (TAC3)-expressing striatal interneuron type within assembloids. To circumvent limitations of in vitro neuronal maturation, we used a neonatal rat transplantation strategy that enabled human Purkinje neurons to develop their hallmark complex dendritic branching. This comprehensive platform yields insights into the factors influencing stem cell-derived neural diversification and maturation.

Filbertone-Induced Nrf2 Activation Ameliorates Neuronal Damage via Increasing BDNF Expression

Neurotrophic factors are endogenous proteins that promote the survival of various neuronal cells. Increasing evidence has suggested a key role for brain-derived neurotrophic factor (BDNF) in the dopaminergic neurotoxicity associated with Parkinson's Disease (PD). This study explores the therapeutic potential of filbertone, a bioactive compound found in hazelnuts, in neurodegeneration, focusing on its effects on neurotrophic factors and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. In our study, filbertone markedly elevated the expression of neurotrophic factors, including BDNF, Glial cell line-Derived Neurotrophic Factor (GDNF), and Nerve Growth Factor (NGF), in human neuroblastoma SH-SY5Y cells, mouse astrocyte C8-D1A cells, and mouse hypothalamus mHypoE-N1 cells. Moreover, filbertone effectively countered neuroinflammation and reversed the decline in neurotrophic factors and Nrf2 activation induced by a high-fat diet (HFD) in neurodegeneration models. The neuroprotective effects of filbertone were further validated in models of neurotoxicity induced by palmitic acid (PA) and the neurotoxin MPTP/MPP+, where it was observed to counteract PA and MPTP/MPP+-induced decreases in cell viability and neuroinflammation, primarily through the activation of Nrf2 and the subsequent upregulation of BDNF and heme oxygenase-1 expression. Nrf2 deficiency negated the neuroprotective effects of filbertone in MPTP-treated mice. Consequently, our finding suggests that filbertone is a novel therapeutic agent for neurodegenerative diseases, enhancing neuronal resilience through the Nrf2 signaling pathway and upregulation of neurotrophic factors.

State-of-the-Art Nrf2 Inhibitors: Therapeutic Opportunities in Non-Cancer Diseases

Nuclear factor erythroid 2-related factor (Nrf2) is a cytoprotective transcription factor that induces the transcription of genes responsible for the cell's response to oxidative stress. While Nrf2 activation has led to the development of clinically relevant therapeutics, the oncogenic role of Nrf2 in the proliferation of cancer cells has underscored the complex nature of Nrf2 and the necessity for the development of Nrf2 inhibitors. Although the application of Nrf2 inhibitors appears limited as anticancer agents, recent studies have begun to pinpoint the impairment of autophagy in diseases as a cellular marker that shifts Nrf2 from a protective to a deleterious state. Therefore, the cytoplasmic accumulation of Nrf2 can lead to the accumulation of lipid hydroperoxides and, ultimately, to ferroptosis. However, some studies aimed at elucidating the role of Nrf2 in non-cancer diseases have yielded conflicting results, attributed to differences in approaches used to inhibit or activate Nrf2, as well as variations in in vitro and/or in vivo disease models. Overall, these results highlight the necessity for a deeper evaluation of Nrf2's role in diseases, especially chronic diseases. In this review, we discuss diseases where Nrf2 inhibition holds potential for beneficial therapeutic effects and summarize recently reported Nrf2 inhibitors exploiting medicinal chemistry approaches suitable for targeting transcription factors like Nrf2.

Potential Protective Effects of Pungent Flavor Components in Neurodegenerative Diseases

Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) have become a major global health burden, but the detailed pathogeneses of neurodegenerative diseases are still unknown, and current treatments are mainly aimed at controlling symptoms; there are no curative treatments for neurodegenerative diseases or treatments for the progressive cognitive, behavioral, and functional impairments that they cause. Studies have shown that some plant extracts with pungent flavor components have a certain neuroprotective effect in neurodegenerative diseases, and their mechanisms mainly involve inhibiting neuronal apoptosis, promoting neuronal regeneration, reducing mitochondrial degeneration, and reducing the production of oxides such as reactive oxygen species in cells, which are of great significance for exploring the treatment of neurodegenerative diseases. In this review, we searched the PubMed database for relevant literature collected in the past 15 years. Finally, we summarized the protective effects of pungent flavor components such as capsaicin, piperine, curcumin, cannabinoids, allicin, and nicotine on the nervous system, focusing on the molecular mechanisms and signaling pathways that they activate. In addition, we also compiled and summarized the laboratory experiments, preclinical experiments, and effects of various pungent flavor components in neurodegenerative diseases. The goal is to further explore their potential as effective drugs for the treatment of neurodegenerative diseases and provide new ideas for further research on the specific protective mechanisms of these substances for the treatment of neurodegenerative diseases and the targets of drug action in the future.

Microglia in retinal diseases: From pathogenesis towards therapeutic strategies

Microglia, a widely dispersed cohort of immune cells in the retina, are intricately involved in a diverse range of pivotal biological processes, including inflammation, vascular development, complement activation, antigen presentation, and phagocytosis. Within the retinal milieu, microglia are crucial for the clearance of dead cells and cellular debris, release of anti-inflammatory agents, and orchestration of vascular network remodeling to maintain homeostasis. In addition, microglia are key mediators of neuroinflammation. Triggered by oxidative stress, elevated intraocular pressure, genetic anomalies, and immune dysregulation, microglia release numerous inflammatory cytokines, contributing to the pathogenesis of various retinal disorders. Recent studies on the ontogeny and broad functions of microglia in the retina have elucidated their characteristics during retinal development, homeostasis, and disease. Furthermore, therapeutic strategies that target microglia and their effector cytokines have been developed and shown positive results for some retinal diseases. Therefore, we systematically review the microglial ontogeny in the retina, elucidate their dual roles in retinal homeostasis and disease pathogenesis, and demonstrate microglia-based targeted therapeutic strategies for retinal diseases.

Advances in human cellular mechanistic understanding and drug discovery of brain organoids for neurodegenerative diseases

The prevalence of neurodegenerative diseases (NDs) is increasing rapidly as the aging population accelerates, and there are still no treatments to halt or reverse the progression of these diseases. While traditional 2D cultures and animal models fail to translate into effective therapies benefit patients, 3D cultured human brain organoids (hBOs) facilitate the use of non-invasive methods to capture patient data. The purpose of this study was to review the research and application of hBO in disease models and drug screening in NDs. The pluripotent stem cells are induced in multiple stages to form cerebral organoids, brain region-specific organoids and their derived brain cells, which exhibit complex brain-like structures and perform electrophysiological activities. The brain region-specific organoids and their derived neurons or glial cells contribute to the understanding of the pathogenesis of NDs and the efficient development of drugs, including Alzheimer's disease, Parkinson's disease, Huntington's disease and Amyotrophic lateral sclerosis. Glial-rich brain organoids facilitate the study of glial function and neuroinflammation, including astrocytes, microglia, and oligodendrocytes. Further research on the maturation enhancement, vascularization and multi-organoid assembly of hBO will help to enhance the research and application of NDs cellular models.

Skin and Induced Pluripotent Stem Cells as Biomarkers for Neurodegenerative Diseases

As the global population ages, the rising prevalence of neurodegenerative diseases, characterized by abnormal protein aggregates, presents significant challenges for early diagnosis and disease monitoring. Identifying accessible tissue biomarkers is crucial for advancing our ability to detect and track the progression of these diseases. Among the most promising biomarkers is the skin, which shares a common embryological origin with the brain and central nervous system (CNS). This biological connection positions the skin as a potential reflection of CNS pathology. Over the past decades, gene expression studies have demonstrated that key genes involved in neurodegenerative diseases are also expressed in skin tissues. Genes such as APP, PSEN1, PPA2, PINK1, LRRK2, PLCB4, MAPT, SPAST, and SPG7 are prominent in this regard. Beyond gene expression, proteins related to neurodegenerative diseases-such as α-synuclein, TAU, PARKIN, and prion protein (PrP)-have been isolated from the skin of affected individuals, underscoring the skin's capacity to mirror neural degeneration. This non-invasive window into neurodegenerative processes is further enhanced by advances in stem cell technology, which have allowed for the generation of human-induced pluripotent stem cells (iPSCs) from patient-derived fibroblasts. These iPSCs offer a valuable model for studying disease mechanisms and developing therapeutic approaches. This review conducts a comprehensive analysis of the literature from databases such as PubMed, Google Scholar, and ResearchGate, emphasizing the unique potential of the skin as a non-invasive biomarker for neurodegenerative diseases. It explores how the skin serves as a bridge between gene expression and disease pathology in both the skin and the CNS. By leveraging this biological connection, the skin emerges as a promising model for enhancing our understanding of neurodegenerative disorders and developing innovative strategies for early detection and treatment. However, significant limitations remain, requiring further validation to establish the specificity and sensitivity of these biomarkers.

In situ chemical reprogramming of astrocytes into neurons: A new hope for the treatment of central neurodegenerative diseases?

Central neurodegenerative disorders (e.g. Alzheimer's disease (AD) and Parkinson's disease (PD)) are tightly associated with extensive neuron loss. Current therapeutic interventions merely mitigate the symptoms of these diseases, falling short of addressing the fundamental issue of neuron loss. Cell reprogramming, involving the transition of a cell from one gene expression profile to another, has made significant strides in the conversion between diverse somatic cell types. This advancement has been facilitated by gene editing techniques or the synergistic application of small molecules, enabling the conversion of glial cells into functional neurons. Despite this progress, the potential for in situ reprogramming of astrocytes in treating neurodegenerative disorders faces challenges such as immune rejection and genotoxicity. A novel avenue emerges through chemical reprogramming of astrocytes utilizing small molecules, circumventing genotoxic effects and unlocking substantial clinical utility. Recent studies have successfully demonstrated the in situ conversion of astrocytes into neurons using small molecules. Nonetheless, these findings have sparked debates, encompassing queries regarding the origin of newborn neurons, pivotal molecular targets, and alterations in metabolic pathways. This review succinctly delineates the background of astrocytes reprogramming, meticulously surveys the principal classes of small molecule combinations employed thus far, and examines the complex signaling pathways they activate. Finally, this article delves into the potential vistas awaiting exploration in the realm of astrocytes chemical reprogramming, heralding a promising future for advancing our understanding and treatment of neurodegenerative diseases.

The Abnormal Proliferation of Midbrain Dopamine Cells From Human Pluripotent Stem Cells Is Induced by Exposure to the Tumor Microenvironment

AIMS

Tumorigenicity is a significant concern in stem cell-based therapies. However, traditional tumorigenicity tests using animal models often produce inaccurate results. Consequently, a more sensitive method for assessing tumorigenicity is required. This study aimed to enhance sensitivity by exposing functional progenitors derived from human pluripotent stem cells (hPSCs) to the tumor microenvironment (TME) in vitro before transplantation, potentially making them more prone to abnormal proliferation or tumorigenicity.

METHODS

Midbrain dopamine (mDA) cells derived from hPSCs were exposed to the TME by coculturing with medulloblastoma. The cellular characteristics of these cocultured mDA cells were evaluated both in vitro and in vivo, and the mechanisms underlying the observed alterations were investigated.

RESULTS

Our findings demonstrated increased proliferation of cocultured mDA cells both in vitro and in vivo. Moreover, these proliferating cells showed a higher expression of Ki67 and SOX1, suggesting abnormal proliferation. The observed abnormal proliferation in cocultured mDA cells was attributed to the hyperactivation of proliferation-related genes, the JAK/STAT3 pathway, and cytokine stimulation.

CONCLUSION

This study indicates that exposing functional progenitors to the TME in vitro before transplantation can induce abnormal proliferation, thereby increasing the sensitivity of tumorigenicity tests.

Extracellular vesicles from human-induced pluripotent stem cell-derived neural stem cells alleviate proinflammatory cascades within disease-associated microglia in Alzheimer's disease

As current treatments for Alzheimer's disease (AD) lack disease-modifying interventions, novel therapies capable of restraining AD progression and maintaining better brain function have great significance. Anti-inflammatory extracellular vesicles (EVs) derived from human induced pluripotent stem cell (hiPSC)-derived neural stem cells (NSCs) hold promise as a disease-modifying biologic for AD. This study directly addressed this issue by examining the effects of intranasal (IN) administrations of hiPSC-NSC-EVs in 3-month-old 5xFAD mice. IN administered hiPSC-NSC-EVs incorporated into microglia, including plaque-associated microglia, and encountered astrocyte soma and processes in the brain. Single-cell RNA sequencing revealed transcriptomic changes indicative of diminished activation of microglia and astrocytes. Multiple genes linked to disease-associated microglia, NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3)-inflammasome and interferon-1 (IFN-1) signalling displayed reduced expression in microglia. Adding hiPSC-NSC-EVs to cultured human microglia challenged with amyloid-beta oligomers resulted in similar effects. Astrocytes also displayed reduced expression of genes linked to IFN-1 and interleukin-6 signalling. Furthermore, the modulatory effects of hiPSC-NSC-EVs on microglia in the hippocampus persisted 2 months post-EV treatment without impacting their phagocytosis function. Such effects were evidenced by reductions in microglial clusters and inflammasome complexes, concentrations of mediators, and end products of NLRP3 inflammasome activation, the expression of genes and/or proteins involved in the activation of p38/mitogen-activated protein kinase and IFN-1 signalling, and unaltered phagocytosis function. The extent of astrocyte hypertrophy, amyloid-beta plaques, and p-tau were also reduced in the hippocampus. Such modulatory effects of hiPSC-NSC-EVs also led to better cognitive and mood function. Thus, early hiPSC-NSC-EV intervention in AD can maintain better brain function by reducing adverse neuroinflammatory signalling cascades, amyloid-beta plaque load, and p-tau. These results reflect the first demonstration of the efficacy of hiPSC-NSC-EVs to restrain neuroinflammatory signalling cascades in an AD model by inducing transcriptomic changes in activated microglia and reactive astrocytes.

Advancements in Engineering Tetrahedral Framework Nucleic Acids for Biomedical Innovations

Tetrahedral framework nucleic acids (tFNAs) are renowned for their controllable self-assembly, exceptional programmability, and excellent biocompatibility, which have led to their widespread application in the biomedical field. Beyond these features, tFNAs demonstrate unique chemical and biological properties including high cellular uptake efficiency, structural bio-stability, and tissue permeability, which are derived from their distinctive 3D structure. To date, an extensive range of tFNA-based nanostructures are intelligently designed and developed for various biomedical applications such as drug delivery, gene therapy, biosensing, and tissue engineering, among other emerging fields. In addition to their role in drug delivery systems, tFNAs also possess intrinsic properties that render them highly effective as therapeutic agents in the treatment of complex diseases, including arthritis, neurodegenerative disorders, and cardiovascular diseases. This dual functionality significantly enhances the utility of tFNAs in biomedical research, presenting valuable opportunities for the development of next-generation medical technologies across diverse therapeutic and diagnostic platforms. Consequently, this review comprehensively introduces the latest advancements of tFNAs in the biomedical field, with a focus on their benefits and applications as drug delivery nanoplatforms, and their inherent capabilities as therapeutic agents. Furthermore, the current limitations, challenges, and future perspectives of tFNAs are explored.

A tumorigenicity evaluation platform for cell therapies based on brain organoids

BACKGROUND

Tumorigenicity represents a critical challenge in stem cell-based therapies requiring rigorous monitoring. Conventional approaches for tumorigenicity evaluation are based on animal models and have numerous limitations. Brain organoids, which recapitulate the structural and functional complexity of the human brain, have been widely used in neuroscience research. However, the capacity of brain organoids for tumorigenicity evaluation needs to be further elucidated.

METHODS

A cerebral organoid model produced from human pluripotent stem cells (hPSCs) was employed. Meanwhile, to enhance the detection sensitivity for potential tumorigenic cells, we created a glioblastoma-like organoid (GBM organoid) model from TP53-/-/PTEN-/- hPSCs to provide a tumor microenvironment for injected cells. Midbrain dopamine (mDA) cells from human embryonic stem cells were utilized as a cell therapy product. mDA cells, hPSCs, mDA cells spiked with hPSCs, and immature mDA cells were then injected into the brain organoids and NOD SCID mice. The injected cells within the brain organoids were characterized, and compared with those injected in vivo to evaluate the capability of the brain organoids for tumorigenicity evaluation. Single-cell RNA sequencing was performed to identify the differential gene expression between the cerebral organoids and the GBM organoids.

RESULTS

Both cerebral organoids and GBM organoids supported maturation of the injected mDA cells. The hPSCs and immature mDA cells injected in the GBM organoids showed a significantly higher proliferative capacity than those injected in the cerebral organoids and in NOD SCID mice. Furthermore, the spiked hPSCs were detectable in both the cerebral organoids and the GBM organoids. Notably, the GBM organoids demonstrated a superior capacity to enhance proliferation and pluripotency of spiked hPSCs compared to the cerebral organoids and the mouse model. Kyoto Encyclopedia of Genes and Genomes analysis revealed upregulation of tumor-related metabolic pathways and cytokines in the GBM organoids, suggesting that these factors underlie the high detection sensitivity for tumorigenicity evaluation.

CONCLUSIONS

Our findings suggest that brain organoids could represent a novel and effective platform for evaluating the tumorigenic risk in stem cell-based therapies. Notably, the GBM organoids offer a superior platform that could complement or potentially replace traditional animal-based models for tumorigenicity evaluation.

Exploring the potential of MFG-E8 in neurodegenerative diseases

Milk fat globule-epidermal growth factor 8 (MFG-E8) is a multifunctional glycoprotein regulating intercellular interactions in various biological and pathological processes. This review summarizes the effects and mechanisms of MFG-E8 in neurodegenerative diseases (NDDs), emphasizing its roles in inflammation, apoptosis, and oxidative stress. In this review, will also explore the potential of MFG-E8 as a diagnostic biomarker and its therapeutic applications in neurodegenerative disorders. Recent studies have revealed intriguing characteristics of using MFG-E8 as a potential drug for treating various brain disorders. While the discovery, origin, expression, and physiological functions of MFG-E8 in various organs and tissues are well defined, its role in the brain remains less understood. This is particularly true for NDDs, indicating unmet medical needs. Elucidating its role in the brain could position MFG-E8 as a potential treatment for NDDs.

Identification of nitric oxide-mediated necroptosis as the predominant death route in Parkinson's disease

Parkinson's disease (PD) involves multiple forms of neuronal cell death, but the dominant pathway involved in disease progression remains unclear. This study employed RNA sequencing (RNA-seq) of brain tissue to explore gene expression patterns across different stages of PD. Using the Scaden deep learning algorithm, we predicted neurocyte subtypes and modelled dynamic interactions for five classic cell death pathways to identify the predominant routes of neuronal death during PD progression. Our cell type-specific analysis revealed an increasing shift towards necroptosis, which was strongly correlated with nitric oxide synthase (NOS) expression across most neuronal subtypes. In vitro experiments confirmed that nitric oxide (NO) is a key mediator of necroptosis, leading to nuclear shrinkage and decreased mitochondrial membrane potential via phosphorylation of the PIP1/PIP3/MLKL signalling cascade. Importantly, specific necroptosis inhibitors significantly mitigated neuronal damage in both in vitro and in vivo PD models. Further analysis revealed that NO-mediated necroptosis is prevalent in early-onset Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS) and across multiple brain regions but not in brain tumours. Our findings suggest that NO-mediated necroptosis is a critical pathway in PD and other neurodegenerative disorders, providing potential targets for therapeutic intervention.

Tau load in select brainstem neurons predicts the severity and nature of balance deficits in the absence of cell death

Patients with tauopathies present with profoundly different clinical symptoms 1 , even within the same disorder 2 . A central hypothesis in the field, well-supported by biomarker studies 3,4 and post-mortem pathology 5-7 , is that clinical heterogeneity reflects differential degeneration of vulnerable neuronal populations responsible for specific neurological functions. Recent work has revealed mechanisms underlying susceptibility of particular cell types 8-10 , but relating tau load to disrupted behavior - es- pecially before cell death - requires a targeted circuit-level approach. Here we studied two distinct balance behaviors in larval zebrafish 11 expressing a human 0N/4R-tau allele 12 in select populations of evolutionarily-conserved and well-characterized brainstem vestibular circuits 13,14 . We observed that human tau load predicted the severity of circuit-specific deficits in posture and navigation in the ab- sence of cell death. Targeting expression to either mid- or hindbrain balance neurons recapitulated these particular deficits in posture and navigation. By parametrically linking tau load in specific neu- rons to early behavioral deficits, our work moves beyond cell type to close the gap between pathological and neurological conceptions of tauopathy.

Advances in different adult stem cell-derived exosomal non-coding RNAs for the treatment of neurological disorders: a narrative review

Neurological disorders are being increasingly recognized as major causes of death and disability around the world. Neurological disorders refer to a broad range of medical conditions that affect the brain and spinal cord. These disorders can have various causes, including genetic factors, infections, trauma, autoimmune reactions, or neurodegenerative processes. Each disorder has its own unique symptoms, progression, and treatment options. Optimal communication between interneurons and neuron-glia cells within the homeostatic microenvironment is of paramount importance. Within this microenvironment, exosomes play a significant role in promoting intercellular communication by transferring a diverse cargo of contents, including proteins, lipids, and non-coding RNAs (ncRNAs). Partially, nervous system homeostasis is preserved by various stem cell-derived exosomal ncRNAs, which include circular RNAs (circRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and PIWI-interacting RNAs (piRNAs). The diversity of these exosomal ncRNAs suggests their potential to influence multiple pathways and cellular processes within the nervous system. Stem cell-derived exosomes and their ncRNA contents have been investigated for potential therapeutic uses in neurological disorders, owing to their demonstrated capabilities in neuroprotection, neuroregeneration, and modulation of disease-related pathways. The ability of stem cell-derived exosomes to cross the blood-brain barrier makes them a promising delivery vehicle for therapeutic ncRNAs. This review aims to summarize the current understanding of different stem cell-derived exosomal ncRNAs and their therapeutic potential and clinical applications.

Cell therapy for neurological disorders

Cell therapies for neurological disorders are entering the clinic and present unique challenges and opportunities compared with conventional medicines. They have the potential to replace damaged nervous tissue and integrate into the brain or spinal cord to produce functional effects for the lifetime of the patient, which could revolutionize the way clinicians treat debilitating neurological disorders. The major challenge has been cell sourcing, which historically relied mainly on fetal brain tissue. This has largely been overcome with the advent of pluripotent stem cell technology and the ability to make almost any cell of the nervous system at scale. Furthermore, advances in gene editing now allow the generation of genetically modified cells that could perform better and evade the immune system. With all the remarkable new approaches to treat neurological disorders, we take a critical look at the state of current clinical trials and how challenges may be overcome with the evolving technology and innovation occurring in the stem cell field.

In vivo and ex vivo gene therapy for neurodegenerative diseases: a promise for disease modification

Neurodegenerative diseases (NDDs), including AD, PD, HD, and ALS, represent a growing public health concern linked to aging and lifestyle factors, characterized by progressive nervous system damage leading to motor and cognitive deficits. Current therapeutics offer only symptomatic management, highlighting the urgent need for disease-modifying treatments. Gene therapy has emerged as a promising approach, targeting the underlying pathology of diseases with diverse strategies including gene replacement, gene silencing, and gene editing. This innovative therapeutic approach involves introducing functional genetic material to combat disease mechanisms, potentially offering long-term efficacy and disease modification. With advancements in genomics, structural biology, and gene editing tools such as CRISPR/Cas9, gene therapy holds significant promise for addressing the root causes of NDDs. Significant progress in preclinical and clinical studies has demonstrated the potential of in vivo and ex vivo gene therapy to treat various NDDs, offering a versatile and precise approach in comparison to conventional treatments. The current review describes various gene therapy approaches employed in preclinical and clinical studies for the treatment of NDDs, including AD, PD, HD, and ALS, and addresses some of the key translational challenges in this therapeutic approach.