Transplantation of stem cell-derived astrocytes for the treatment of amyotrophic lateral sclerosis and spinal cord injury

Neglected for years, astrocytes are now recognized to fulfill and support many, if not all, homeostatic functionsof the healthy central nervous system(CNS). During neurodegenerative diseases such as amyotrophic lateral sclerosis(ALS) and spinal cord injury(SCI), astrocytes in the vicinity of degenerating areas undergo both morphological and functional changes that might compromise their intrinsic properties. Evidence from human and animal studies show that deficient astrocyte functions or loss-of-astrocytes largely contribute to increased susceptibility to cell death for neurons, oligodendrocytes and axons during ALS and SCI disease progression. Despite exciting advances in experimental CNS repair, most of current approaches that are translated into clinical trials focus on the replacement or support of spinal neurons through stem cell transplantation, while none focus on the specific replacement of astroglial populations. Knowing the important functions carried out by astrocytes in the CNS, astrocyte replacement-based therapies might be a promising approach to alleviate overall astrocyte dysfunction, deliver neurotrophic support to degenerating spinal tissue and stimulate endogenous CNS repair abilities. Enclosed in this review, we gathered experimental evidence that argue in favor of astrocyte transplantation during ALS and SCI. Based on their intrinsic properties and according to the cell type transplanted, astrocyte precursors or stem cell-derived astrocytes promote axonal growth, support mechanisms and cells involved in myelination, are able to modulate the host immune response, deliver neurotrophic factors and provide protective molecules against oxidative or excitotoxic insults, amongst many possible benefits. Embryonic or adult stem cells can even be genetically engineered in order to deliver missing gene products and therefore maximize the chance of neuroprotection and functional recovery. However, before broad clinical translation, further preclinical data on safety, reliability and therapeutic efficiency should be collected. Although several technical challenges need to be overcome, we discuss the major hurdles that have already been met or solved by targeting the astrocyte populationin experimental ALS and SCI models and we discuss avenues for future directions based on latest molecular findings regarding astrocyte biology.

Reversing multiple age-related pathologies by controlling the senescence-associated secretory phenotype of stem cells

Regenerative medicine by cell transplantation is a novel therapy for treating end-stage organ failure and tissue damage. Cell-based therapy based on the transplantation of neural stem/progenitor cells （NSPCs） represents an attractive strategy for the treatment of neurodegenerative diseases, but obtaining large numbers of these cells is difficult and their differentiation potential is strictly restricted in a spatiotemporally-regulated manner during central nervous system （CNS） development. Therefore, embryonic stem cells and induced pluripotent stem cells represent an attractive alternative for cell-transplantation therapy in regenerative medicine.

Combination of CRISPR/Cas9 System and CAR-T Cell Therapy:A New Era for Refractory and Relapsed Hematological Malignancies

Chimeric antigen receptor T(CAR-T)cell therapy is the novel treatment strategy for hematological malignancies such as acute lymphoblastic leukemia(ALL),lymphoma and multiple myeloma.However,treatment-related toxicities such as cytokine release syndrome(CRS)and immune effector cell-associated neurotoxicity syndrome(ICANS)have become significant hurdles to CAR-T treatment.Multiple strategies were established to alter the CAR structure on the genomic level to improve efficacy and reduce toxicities.Recently,the innovative gene-editing technology-clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated nuclease9(Cas9)system,which particularly exhibits preponderance in knock-in and knockout at specific sites,is widely utilized to manufacture CAR-T products.The application of CRISPR/Cas9 to CAR-T cell therapy has shown promising clinical results with minimal toxicity.In this review,we summarized the past achievements of CRISPR/Cas9 in CAR-T therapy and focused on the potential CAR-T targets.

Differentiation of Wharton's jelly mesenchymal stem cells into neurons in alginate scaffold

Alginate scaffold has been considered as an appropriate biomaterial for promoting the differentiation of embryonic stem cells toward neuronal cell lineage. We hypothesized that alginate scaffold is suitable for culturing Wharton’s jelly mesenchymal stem cells（WJMSCs） and can promote the differentiation of WJMSCs into neuron-like cells. In this study, we cultured WJMSCs in a three-dimensional scaffold fabricated by 0.25% alginate and 50 m M Ca Cl2 in the presence of neurogenic medium containing 10 μM retinoic acid and 20 ng/m L basic fibroblast growth factor. These cells were also cultured in conventional two-dimensional culture condition in the presence of neurogenic medium as controls. After 10 days, immunofluorescence staining was performed for detecting β-tubulin（marker for WJMSCs-differentiated neuron） and CD271（motor neuron marker）. β-Tubulin and CD271 expression levels were significantly greater in the WJMSCs cultured in the three-dimensional alginate scaffold than in the conventional two-dimensional culture condition. These findings suggest that three-dimensional alginate scaffold cell culture system can induce neuronal differentiation of WJMSCs effectively.

Effect of Trastuzumab on Notch-1 Signaling Pathway in Breast Cancer SK-BR3 Cells

Objective： To investigate the effects and mechanisms of trastuzumab on Notch-1 pathway in breast cancer cells, recognizing the significance of Notch-1 signaling pathway in trastuzumab resistance. Methods： Immunocytochemistry staining and Western blotting were employed to justify the expression of Notch-1 protein in HER2-overexpressing SK-BR3 cells and HER2-non-overexpressing breast cancer MDA-MB-231 cells. Western blotting and reverse transcription PCR （RT-PCR） were used to detect the activated Notch-1 and Notch-1 target gene HES-1 mRNA expression after SK-BR3 cells were treated with trastuzumab. Double immunofluorescence staining and co-immunoprecipitation were used to analyze the relationship of Notch-1 and HER2 proteins. Results： The level of Notch-1 nuclear localization and activated Notch-1 proteins in HER2-overexpressing cells were significantly lower than in HER2-non-overexpressing cells （P0.01）, and the expressions of activated Notch-1 and HES-1 mRNA were obviously increased after trastuzumab treatment （P0.05）, but HER2 expression did not change significantly for trastuzumab treating （P0.05）. Moreover, Notch-1 was discovered to co-localize and interact with HER2 in SK-BR3 cells. Conclusion： Overexpression of HER2 decreased Notch-1 activity by the formation of a HER2-Notch1 complex, and trastuzumab can restore the activity of Notch-1 signaling pathway, which could be associated with cell resistance to trastuzumab.

R102W mutation in the RS1 gene responsible for retinoschisis and recurrent glaucoma

AIM: To identify the mutations in RS1 gene associated with typical phenotype of X-linked juvenile retinoschisis(XLRS) and a rare condition of concomitant glaucoma. ·METHODS: Complete ophthalmic examinations were performed in the proband. The coding regions of the RS1 gene that encode retinoschisin were amplified by polymerase chain reaction and directly sequenced. ·RESULTS: The proband showed a typical phenotype of XLRS with large peripheral retinal schisis in both eyes,involving the macula and combined with foveal cystic change,reducing visual acuity. A typical phenotype of recurrent glaucoma with high intraocular pressure(IOP) and reduced visual field was also demonstrated with the patient. Mutation analysis of RS1 gene revealed R102W(c.304C】T) mutations in the affected male,and his mother was proved to be a carrier with the causative mutation and another synonymous polymorphism(c.576C】CT). ·CONCLUSION: We identified the genetic variations of a Chinese family with typical phenotype of XLRS and glaucoma. The severe XLRS phenotypes associated with R102W mutations reveal that the mutation determines a notable alteration in the function of the retinoschisin protein. Identification of the disease-causing mutation is beneficial for future clinical references.

Bioengineered functional humanized livers： An emerging supportive modality to bridge the gap of organ transplantation for management of end-stage liver diseases

End stage liver diseases （ESLD） represent a major, neglected global public health crisis which requires an urgent action towards fnding a proper cure. Orthotro-pic liver transplantation has been the only definitive treatment modality for ESLD. However, shortage of donor organs, timely unavailability, post-surgery related complications and financial burden on the patients li-mits the number of patients receiving the transplants. Since last two decades cell-based therapies have revolu-tionized the feld of organ/tissue regeneration. However providing an alternative organ source to address the donor liver shortage still poses potential challenges. The developments made in this direction provide useful futuristic approaches, which could be translated into preclinical and clinical settings targeting appropriate applications in specific disease conditions. Earlier studies have demonstrated the applicability of this particular approach to generate functional organ in rodent system by connecting them with portal and hepatic circulatory networks. However, such strategy requires very high level of surgical expertise and also poses the technical and financial questions towards its future applicability. Hence, alternative sites for generating secondary organs are being tested in several types of disease conditions. Among different sites, omentum has been proved to be more appropriate site for implanting several kinds of functional tissue constructs without eliciting much immunological response. Hence, omentum may be con-sidered as better site for transplanting humanized bio-engineered ex vivo generated livers, thereby creating a secondary organ at intra-omental site. However, the expertise for generating such bioengineered organs are limited and only very few centres are involved for inve-stigating the potential use of such implants in clinical practice due to gap between the clinical transplant surgeons and basic scientists working on the concept evolution. Herein we discuss the recent advances and challenges to create functional secondary organs thr-ough intra-omental transplantation of ex vivo genera-ted bioengineered humanized livers and their further application in the management of ESLD as a supportive bridge for organ transplantation.

Cell-free mitochondrial DNA quantification in ischemic stroke patients for non-invasive and real-time monitoring of disease status

BACKGROUND Acute ischemic stroke(AIS)is one of the major causes of the continuous increasing rate of global mortality due to the lack of timely diagnosis,prognosis,and management.This study provides a primitive platform for non-invasive and cost-effective diagnosis and prognosis of patients with AIS using circulating cellfree mitochondrial DNA(cf-mtDNA)quantification and validation.AIM To evaluate the role of cf-mtDNA as s non-invasive,and affordable tool for realtime monitoring and prognosticating AIS patients at disease onset and during treatment.METHODS This study enrolled 88 participants including 44 patients with AIS and 44 healthy controls with almost similar mean age group at stroke onset,and at 24 h and 72 h of treatment.Peripheral blood samples were collected from each study participant and plasma was separated using centrifugation.The cf-mtDNA concentration was quantified using nanodrop reading and validated through real-time quantitative polymerase chain reaction(RT-qPCR)of NADH-ubiquinone oxidoreductase chain 1(ND1)relative transcript expression levels.RESULTS Comparative analysis of cf-mtDNA concentration in patients at disease onset showed significantly increased levels compared to control individuals for both nanodrop reading,as well as ND1 relative expression levels(P<0.0001).Intergroup analysis of cf-mtDNA concentration using nanodrop showed significantly reduced levels in patients at 72 h of treatment compared to onset(P<0.01).However,RT-qPCR analysis showed a significant reduction at 24 h and 72 h of treatment compared to the disease onset(P<0.001).The sensitivity and specificity were relatively higher for RT-qPCR than nanodrop-based cfmtDNA quantification.Correlation analysis of both cf-mtDNA concentration as well as ND1 relative expression with National Institute of Health Stroke Scale score at baseline showed a positive trend.CONCLUSION In summary,quantitative estimation of highly pure cf-mtDNA provides a simple,highly sensitive and specific,non-invasive,and affordable approach for real-time monitoring and prognosticating AIS patients at onset and during treatment.

Differentiation of Menstrual Blood Derived Stem Cell (MensSCs) to Hepatocyte-Liked Cell on Three Dimensional Nanofiberscaffold: Poly Caprolacton (PCL)

Menstrual blood stem cells (MensSCs) have enormous potential as a source for cell replacement therapies. Since there is a major concern in utilization of nanofibers in tissue engineering of stem cells, we examined the potential of MensSCs to differentiate into hepatocytes, using different protocols and compare cells, with two-dimensional (2D) and three-dimensional (3D) culture systems. Cell characterization experiments of MensSCs have demonstrated that they are multipotent stem cells similar to mesenchymal stem cells, which can successfully differentiate into osteogenic and adipogenic lineages. The efficiency of the cells on the scaffold was appraised by scanning electron microscopy (SEM), MTT assay, and hematoxylin and eosin (H&E) staining. Thereafter, the differentiation protocols were developed by hepatocyte growth factor (HGF) and oncostatin M (OSM) with serum-supplemented or serum-free culture media up to 30 days. Immunofluorescence analysis and ELISA assay revealed the expression of albumin (ALB) in differentiated cells. Hepatocyte-like cells expressed liver-specific gene such as albumin(ALB), α-fetoprotein (AFP), tyrosine aminotransferase (TAT) and cytochrome P450 subunit 7a1 (Cyp7a1) at mRNA levels. In conclusion, the evidences presented in this study show that the nanofiber scaffold and MensSCs may provide a source of differentiated cells for treatment of liver diseases.

Bioengineered humanized livers as better three-dimensional drug testing model system

AIM To develop appropriate humanized three-dimensional ex-vivo model system for drug testing. METHODS Bioengineered humanized livers were developed in this study using human hepatic stem cells repopulation within the acellularized liver scaffolds which mimics with the natural organ anatomy and physiology. Six cytochrome P-450 probes were used to enable efficient identification of drug metabolism in bioengineered humanized livers. The drug metabolism study in bioengineered livers was evaluated to identify the absorption, distribution, metabolism, excretion and toxicity responses.RESULTS The bioengineered humanized livers showed cellular and molecular characteristics of human livers. The bioengineered liver showed three-dimensional natural architecture with intact vasculature and extra-cellular matrix. Human hepatic cells were engrafted similar to the human liver. Drug metabolism studies provided a suitable platform alternative to available ex-vivo and in vivo models for identifying cellular and molecular dynamics of pharmacological drugs.CONCLUSION The present study paves a way towards the development of suitable humanized preclinical model systems for pharmacological testing. This approach may reduce the cost and time duration of preclinical drug testing and further overcomes on the anatomical and physiological variations in xenogeneic systems.

Role of cell-free DNA for predicting incidence and outcome of patients with ischemic stroke

Early diagnosis and prognosis of ischemic stroke remains a critical challenge in clinical settings.A blood biomarker can be a promising quantitative tool to represent the clinical manifestations in ischemic stroke.Cell-free DNA(cfDNA)has recently turned out to be a popular circulating biomarker due to its potential relevance for diagnostic applications in a variety of disorders.Despite bright outlook of cfDNA in clinical applications,very less is known about its origin,composition,or function.Several recent studies have identified cell-derived mitochondrial components including mitochondrial DNA(mtDNA)in the extracellular spaces including blood and cerebrospinal fluid.However,the time course of alterations in plasma mtDNA concentrations in patients after an ischemic stroke is poorly understood.DNA is thought to be freed into the plasma shortly after the commencement of an ischemic stroke and then gradually decreased.However,the importance of cell-free mtDNA(cf-mtDNA)in ischemic stroke is still unknown.This review summarizes about the utility of biomarkers which has been standardized in clinical settings and role of cfDNA including cfmtDNA as a non-invasive potential biomarker of ischemic stroke.

Generating hematopoietic cells from human pluripotent stem cells:approaches,progress and challenges

Human pluripotent stem cells(hPSCs)have been suggested as a potential source for the production of blood cells for clinical application.In two decades,almost all types of blood cells can be successfully generated from hPSCs through various differentiated strategies.Meanwhile,with a deeper understanding of hematopoiesis,higher efficiency of generating progenitors and precursors of blood cells from hPSCs is achieved.However,how to generate large-scale mature functional cells from hPSCs for clinical use is still difficult.In this review,we summarized recent approaches that generated both hematopoietic stem cells and mature lineage cells from hPSCs,and remarked their efficiency and mechanisms in producing mature functional cells.We also discussed the major challenges in hPSC-derived products of blood cells and provided some potential solutions.Our review summarized efficient,simple,and defined methodologies for developing good manufacturing practice standards for hPSC-derived blood cells,which will facilitate the translation of these products into the clinic.

Correction:Generating hematopoietic cells from human pluripotent stem cells:approaches,progress and challenges

Correction:Cell Regen 12,31(2023).https://doi.org/10.1186/s13619-023-00175-6 Following publication of the original article(Zheng et al.2023),the authors reported that Figs.1 and 2 were in the wrong order.The correct Figs.1 and 2 have been provided in this Correction.The original article(Zheng et al.2023)has been corrected.

Efficient expansion of rare human circulating hematopoietic stem/progenitor cells in steady-state blood using a polypeptide-forming 3D culture

Although widely applied in treating hematopoietic malignancies,transplantation of hematopoietic stem/progenitor cells(HSPCs)is impeded by HSPC shortage.Whether circulating HSPCs(cHSPCs)in steady-state blood could be used as an alternative source remains largely elusive.Here we develop a three-dimensional culture system(3DCS)including arginine,glycine,aspartate,and a series of factors.Fourteen-day culture of peripheral blood mononuclear cells(PBMNCs)in 3DCS led to 125-and 70-fold increase of the frequency and number of CD34+cells.Further,3DCS-expanded cHSPCs exhibited the similar reconstitution rate com-pared to CD34+HSPCs in bone marrow.Mechanistically,3DCS fabricated an immunomodulatory niche,secreting cytokines as TNF to support cHSPC survival and proliferation.Finally,3DCS could also promote the expansion of cHSPCs in patients who failed in HSPC mobilization.Our 3DCS successfully expands rare cHSPCs,providing an alternative source for the HSPC therapy,particularly for the patients/donors who have failed in HSPC mobilization.

MSC-mediated mitochondrial transfer restores mitochondrial DNA and function in neural progenitor cells of Leber’s hereditary optic neuropathy

Leber’s hereditary optic neuropathy(LHON)is a debilitating mitochondrial disease associated with mutations in mitochondrial DNA(mtDNA).Unfortunately,the available treatment options for LHON patients are limited due to challenges in mitochondrial replacement.In our study,we reprogramming LHON urine cells into induced pluripotent stem cells(iPSCs)and differentiating them into neural progenitor cells(NPCs)and neurons for disease modeling.Our research revealed that LHON neurons exhibited significantly higher levels of mtDNA mutations and reduced mitochondrial function,confirming the disease phenotype.However,through co-culturing LHON iPSC-derived NPCs with mesenchymal stem cells(MSCs),we observed a remarkable rescue of mutant mtDNA and a significant improvement in mitochondrial metabolic function in LHON neurons.These findings suggest that co-culturing with MSCs can enhance mitochondrial function in LHON NPCs,even after their differentiation into neurons.This discovery holds promise as a potential therapeutic strategy for LHON patients.

A versatile tool for tracking the differentiation of human embryonic stem cells

The ability of human embryonic stem cells(hESCs)to undergo indefinite self-renewal in vitro and to produce lineages derived from all three embryonic germ layers both in vitro and in vivo makes such cells extremely valuable in both clinical and research settings.However,the generation of specialized cell lineages from a mixture of differentiated hESCs remains technically difficult.Tissue specific promoter-driven reporter genes are power-ful tools for tracking cell types of interest in differentiated cell populations.Here,we describe the construction of modular lentivectors containing different tissue-specific promoters(Tα1 ofα-tubulin;aP2 of adipocyte Protein 2;and AFP of alpha fetoprotein)driving expression of humanized Renilla greenfluorescent protein(hrGFP).To this end,we used MultiSite gateway technology and employed the novel vectors to successfully monitor hESC differentiation.We present a versatile method permitting target cells to be traced.Our system will facilitate research in developmental biology,transplantation,and in vivo stem cell tracking.

Mesenchymal stem cells for treatment of steroid-resistant acute rejection after liver transplantation

A patient with steroid-resistant acute rejection 50 days after ABO-compatible orthotopic liver transplantation(LT)received regular infusion of allogeneic mesenchymal stem cells(MSCs)after three sessions of steroid pulse therapy which failed to control the pathogenetic condition as shown by biopsy.Liver function improved gradually after intravenous injection of MSCs once weekly for 10 weeks(as confirmed by biopsy)and remained stable under administration of conventional immunosuppressive agents.There was no evidence of neoplasms 5 years after treatment.MSCs infusion appears to successfully reverse resistance to immunosuppressive agents and may be a useful treatment for post-liver transplant steroid-resistant rejection.

Role of autophagy in acute myeloid leukemia therapy

Despite its dual role in determining cell fate in a wide array of solid cancer cell lines, autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis. However, autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein, though the molecular mechanism remains elusive. Nevertheless, since it can induce cooperation with apoptosis and differentiation in response to autophagic signals, autophagy can be manipulated for a better therapy on acute myeloid leukemia.

Decellularized optic nerve functional scaffold transplant facilitates directional axon regeneration and remyelination in the injured white matter of the rat spinal cord

Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury.However,achieving good outcome remains difficult.Our previous study showed that porcine decellularized optic nerve better mimics the extracellular matrix of the embryonic porcine optic nerve and promotes the directional growth of dorsal root ganglion neurites.However,it has not been reported whether this material promotes axonal regeneration in vivo.In the present study,a porcine decellularized optic nerve was seeded with neurotrophin-3-overexpressing Schwann cells.This functional scaffold promoted the directional growth and remyelination of regenerating axons.In vitro,the porcine decellularized optic nerve contained many straight,longitudinal channels with a uniform distribution,and microscopic pores were present in the channel wall.The spatial micro topological structure and extracellular matrix were conducive to the adhesion,survival and migration of neural stem cells.The scaffold promoted the directional growth of dorsal root ganglion neurites,and showed strong potential for myelin regeneration.Furthermore,we transplanted the porcine decellularized optic nerve containing neurotrophin-3-overexpressing Schwann cells in a rat model of T10 spinal cord defect in vivo.Four weeks later,the regenerating axons grew straight,the myelin sheath in the injured/transplanted area recovered its structure,and simultaneously,the number of inflammatory cells and the expression of chondroitin sulfate proteoglycans were reduced.Together,these findings suggest that porcine decellularized optic nerve loaded with Schwann cells overexpressing neurotrophin-3 promotes the directional growth of regenerating spinal cord axons as well as myelin regeneration.All procedures involving animals were conducted in accordance with the ethical standards of the Institutional Animal Care and Use Committee of Sun Yat-sen University(approval No.SYSU-IACUC-2019-B034)on February 28,2019.

An NT-3-releasing bioscaffold supports the formation of TrkC-modified neural stem cell-derived neural network tissue with efficacy in repairing spinal cord injury

The mechanism underlying neurogenesis during embryonic spinal cord development involves a specific ligand/receptor interaction,which may be help guide neuroengineering to boost stem cell-based neural regeneration for the structural and functional repair of spinal cord injury.Herein,we hypothesized that supplying spinal cord defects with an exogenous neural network in the NT-3/fibroin-coated gelatin sponge(NF-GS)scaffold might improve tissue repair efficacy.To test this,we engineered tropomyosin receptor kinase C(TrkC)-modified neural stem cell(NSC)-derived neural network tissue with robust viability within an NF-GS scaffold.When NSCs were genetically modified to overexpress TrkC,the NT-3 receptor,a functional neuronal population dominated the neural network tissue.The pro-regenerative niche allowed the long-term survival and phenotypic maintenance of the donor neural network tissue for up to 8 weeks in the injured spinal cord.Additionally,host nerve fibers regenerated into the graft,making synaptic connections with the donor neurons.Accordingly,motor function recovery was significantly improved in rats with spinal cord injury(SCI)that received TrkC-modified NSC-derived neural network tissue transplantation.Together,the results suggested that transplantation of the neural network tissue formed in the 3D bioactive scaffold may represent a valuable approach to study and develop therapies for SCI.