Protective effects of mesenchymal stem cells on ischemic brain injury: therapeutic perspectives of regenerative medicine

Mesenchymal stem cell therapy in ischemic stroke trials. A systematic review

Cerebrovascular accidents, also known as strokes, are the leading cause of permanent disability in society, presenting significant socioeconomic and healthcare costs. They can be caused by ischemic factors or hemorrhages, with ischemic strokes being the most common among the population. Therapies for patients suffering from this condition are limited and primarily focus on acute-phase treatment. In recent years, there has been an increase in cellular therapies, employing Stem Cells to mitigate or eliminate the consequences arising from this disease. Mesenchymal Stem Cells (MSCs) hold substantial therapeutic potential in Nervous System pathologies due to their low antigenicity and capacity to differentiate into various human tissues, such as adipogenic, chondrogenic, and osteogenic tissues. This study conducts a literature review using the "clinical trials" and "Pubmed" database, summarizing all ongoing clinical trials for ischemic strokes that utilize MSCs as treatment.

A review of the advances, insights, and prospects of gene therapy for Alzheimer's disease: A novel target for therapeutic medicine

Neurodegenerative diseases such as Alzheimer's disease (AD) are still an important issue for scientists because it is difficult to cure with the available molecular medications and conventional treatments. Due to the complex nature of the brain structures and heterogeneous morphological and physiological properties of neuronal cells, interventions for cerebral-related disorders using surgical approaches, and classical and ongoing treatments remain hard for physicians. Furthermore, the development of newly designed medications attempts to target AD are not successful in improving AD, because abnormalities of tau protein, aggregation of amyloid β (Aβ) peptide, inflammatory responses, etc lead to advanced neurodegeneration processes that conventional treatments cannot stop them. In recent years, novel diagnostic strategies and therapeutic approaches have been developed to identify and cure early pathological events of AD. Accordingly, many gene-based therapies have been developed and introduce the therapeutic potential to prevent and cure AD. On the other hand, genetic investigations and postmortem assessments have detected a large number of factors associated with AD pathology. Also, genetically diverse animal models of AD help us to detect and prioritize novel resilience mechanisms. Hence, gene therapy can be considered an effective and powerful tool to identify and treat human diseases. Ultimately, gene study and gene-based therapy with a critical role in the detection and cure of various human disorders will have a fundamental role in our lives forever. This scientific review paper discusses the present status of different therapeutic strategies, particularly gene-based therapy in treating AD, along with its challenges.

A New Strategy for the Regulation of Neuroinflammation: Exosomes Derived from Mesenchymal Stem Cells

Neuroinflammation is an important pathogenesis of neurological diseases and causes a series of physiopathological changes, such as abnormal activation of glial cells, neuronal degeneration and death, and disruption of the blood‒brain barrier. Therefore, modulating inflammation may be an important therapeutic tool for treating neurological diseases. Mesenchymal stem cells (MSCs), as pluripotent stem cells, have great therapeutic potential for neurological diseases due to their regenerative ability, immunity, and ability to regulate inflammation. However, recent studies have shown that MSC-derived exosomes (MSC-Exos) play a major role in this process and play a key role in neuroprotection by regulating neuroglia. This review summarizes the recent progress made in regulating neuroinflammation by focusing on the mechanisms by which MSC-Exos are involved in the regulation of glial cells through signaling pathways such as the TLR, NF-κB, MAPK, STAT, and NLRP3 pathways to provide some references for subsequent research and therapy.

Upregulation of mitochondrial PGK1 by ROS-TBC1D15 pathway promotes neuronal death after oxygen-glucose deprivation/reoxygenation injury

Phosphoglycerate kinase 1 (PGK1) is extensively located in the cytosol and mitochondria. The role of PGK1 in ischemic neuronal injury remains elusive. In the in vitro model of oxygen-glucose deprivation/reoxygenation (OGD/R), we showed that PGK1 expression was increased in cortical neurons. Knockdown of PGK1 led to a reduction of OGD/R-induced neuronal death. The expression of cytosolic PGK1 was reduced, but the levels of mitochondrial PGK1 were increased in OGD/R-insulted neurons. Inhibiting the activity of mitochondrial PGK1 alleviated the neuronal injury after OGD/R insult. We further showed that the protein levels of TBC domain family member 15 (TBC1D15) were decreased in OGD/R-insulted neurons. Knockdown of TBC1D15 led to increased levels of mitochondrial PGK1 after OGD/R insult in cortical neurons. Moreover, increased reactive oxygen species (ROS) resulted in a reduction of TBC1D15 in OGD/R-insulted neurons. These results suggest that the upregulation of mitochondrial PGK1 by ROS-TBC1D15 signaling pathway promotes neuronal death after OGD/R injury. Mitochondrial PGK1 may act as a regulator of neuronal survival and interventions in the PGK1-dependent pathway may be a potential therapeutic strategy.

FNDC5 inhibits autophagy of bone marrow mesenchymal stem cells and promotes their survival after transplantation by downregulating Sp1

Regenerative therapy based on mesenchymal stem cells (MSCs) has great promise to achieve functional recovery in cerebral infarction patients. However, the survival rate of transplanted MSCs is extremely low because of destructive autophagy caused by the harsh ischemic microenvironment in cerebral infarct tissue. The mechanism by which fibronectin type III domain protein 5 (FNDC5) regulates autophagy of transplanted bone marrow-MSCs (BMSCs) following ischemic injury needs to be elucidated. In this study, we confirmed that FNDC5 promotes the survival of transplanted BMSCs in a rat cerebral infarction model. Furthermore, bioinformatic analysis and verification experiments revealed the transcription factor, Sp1, to be a key mediator of autophagy regulation by FNDC5. FNDC5 significantly inhibited BMSC autophagy by down-regulating Sp1 and the autophagy-related Sp1-target gene, ULK2. Transplanted BMSCs overexpressing FNDC5 (BMSCs-OE-FNDC5) promoted neurovascular proliferation and alleviated ischemic brain injury in cerebral infarct model rats. However, the increased survival and enhanced neuroprotective effect of transplanted BMSCs-OE-FNDC5 were reversed by simultaneous overexpression of Sp1. Our data indicate a role for FNDC5 in BMSC survival and reveal a novel mechanism of transcription regulation through Sp1 for the autophagy-related gene ULK2. Modulation of FNDC5 may promote survival capacity and improve the therapeutic effect of BMSCs in various tissues following ischemia.

The impact of particulate matters on apoptosis in various organs: Mechanistic and therapeutic perspectives

Ecological air contamination is the non-homogenous suspension of insoluble particles into gas or/and liquid fluids known as particulate matter (PM). It has been discovered that exposure to PM can cause serious cellular defects, followed by tissue damage known as cellular stress. Apoptosis is a homeostatic and regulated phenomenon associated with distinguished physiological actions inclusive of organ and tissue generation, aging, and development. Moreover, it has been proposed that the deregulation of apoptotic performs an active role in the occurrence of many disorders, such as autoimmune disease, neurodegenerative, and malignant, in the human population. Recent studies have shown that PMs mainly modulate multiple signaling pathways involved in apoptosis, including MAPK, PI3K/Akt, JAK/STAT, NFκB, Endoplasmic Stress, and ATM/P53, leading to apoptosis dysregulation and apoptosis-related pathological conditions. Here, the recently published data concerning the effect of PM on the apoptosis of various organs, with a particular focus on the importance of apoptosis as a component in PM-induced toxicity and human disease development, is carefully discussed. Moreover, the review also highlighted the various therapeutic approaches, including small molecules, miRNA replacement therapy, vitamins, and PDRN, for treating diseases caused by PM toxicity. Notably, researchers have considered medicinal herbs a potential treatment for PM-induced toxicity due to their fewer side effects. So, in the final section, we analyzed the performance of some natural products for inhibition and intervention of apoptosis arising from PM-induced toxicity.

Dedifferentiated fat cells: current applications and future directions in regenerative medicine

Stem cell therapy is the most promising treatment option for regenerative medicine. Therapeutic effect of different stem cells has been verified in various disease model. Dedifferentiated fat (DFAT) cells, derived from mature adipocytes, are induced pluripotent stem cells. Compared with ASCs and other stem cells, the DFAT cells have unique advantageous characteristics in their abundant sources, high homogeneity, easily harvest and low immunogenicity. The DFAT cells have shown great potential in tissue engineering and regenerative medicine for the treatment of clinical problems such as cardiac and kidney diseases, autoimmune disease, soft and hard tissue defect. In this review, we summarize the current understanding of DFAT cell properties and focus on the relevant practical applications of DFAT cells in cell therapy in recent years.

C1q/Tumor Necrosis Factor-Related Protein 9: Basics and Therapeutic Potentials

C1q/tumor necrosis factor-related protein 9 (CTRP9) is a newly discovered adipokine that is the closest paralog of adiponectin. Proteolytic cleavage of CTRP9 leads to the release of the globular domain (gCTRP9), which serves as the major circulating subtype. After binding with adiponectin receptor 1 (AdipoR1) and N-cadherin, CTRP9 activates various signaling pathways to regulate glucose and lipid metabolism, vasodilation and cell differentiation. Throughout human development and adult life, CTRP9 controls many biological phenomena. simultaneously, abnormal gene or protein expression of CTRP9 is accompanied by a wide range of human pathological phenomena. In this review, we briefly introduce CTRP9 and its associated signaling pathways and physiological functions, which may be helpful in the understanding of the occurrence of diseases. Moreover, we summarize the broader research prospects of CTRP9 and advances in therapeutic intervention. In recent years, CTRP9 has attracted extensive attention due to its role in the pathogenesis of various diseases, providing further avenues for its exploitation as a potential biomarker or therapeutic target.

Dendrobium officinale polysaccharide-induced neuron-like cells from bone marrow mesenchymal stem cells improve neuronal function a rat stroke model

Various methods have been used to induce the neuronal differentiation of marrow mesenchymal stem cells (MSCs). However, the limited induction efficiency of cells in vitro has restricted their use. Therefore, identifying a simple and efficient treatment method is necessary. Dendrobium officinale is an important traditional Chinese medicine, and its main component, polysaccharides, has many pharmacological activities. However, the effects of D. officinale polysaccharide (DOP) on the neuronal differentiation of bone marrow mesenchymal stem cells (BMSCs) and treatment of ischaemic stroke remain unknown. We found that DOP promoted the neuronal differentiation of BMSCs by increasing the expression levels of neural markers, and the optimal concentration of DOP was 25 μg/mL. Additionally, the Notch signalling pathway was inhibited during the neuronal differentiation of BMSCs induced by DOP, and this effect was strengthened using an inhibitor of this pathway. The Wnt signalling pathway was activated during the differentiation of BMSCs, and inhibition of the Wnt signalling pathway downregulated the expression of neuronal genes. Furthermore, the transplantation of neuron-like cells induced by DOP improved neuronal recovery, as the brain infarct volume, neurologic severity scores and levels of inflammatory factors were all significantly reduced in vivo. In conclusion, DOP is an effective inducer of the neuronal differentiation of BMSCs and treatment option for ischaemic stroke.

Adult stem cell transplantation combined with conventional therapy for the treatment of end-stage liver disease: a systematic review and meta-analysis

End-stage liver disease (ESLD) is characterized by the deterioration of liver function and a subsequent high mortality rate. Studies have investigated the use of adult stem cells to treat ESLD. Here, a systematic review and meta-analysis was conducted to determine the efficacy of a combination therapy with adult stem cell transplantation and traditional medicine for treating ESLD. Four databases-including PubMed, Web of Science, Embase, and Cochrane Library-were investigated for studies published before January 31, 2021. The main outcome indicators were liver function index, model for end-stage liver disease (MELD) scores, and Child‒Turcotte‒Pugh (CTP) scores. Altogether, 1604 articles were retrieved, of which eight met the eligibility criteria; these studies included data for 579 patients with ESLD. Combination of adult stem cell transplantation with conventional medicine significantly improved its efficacy with respect to liver function index, CTP and MELD scores, but this effect gradually decreased over time. Moreover, a single injection of stem cells was more effective than two injections with respect to MELD and CTP scores and total bilirubin (TBIL) and albumin (ALB) levels, with no significant difference in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. With respect to the TBIL levels, patients receiving mononuclear cells (MNCs) experienced a significantly greater therapeutic effect-starting from twenty-four weeks after the treatment-whereas with respect to ALB levels, CD34⁺ autologous peripheral blood stem cells (CD34⁺ APBSCs) and MNCs had similar therapeutic effects. Severe complications associated with adult stem cell treatment were not observed. Although the benefits of combination therapy with respect to improving liver function were slightly better than those of the traditional treatment alone, they gradually decreased over time.Systematic review registration: PROSPERO registration number: CRD42021238576.

Adult Hippocampal Neurogenesis and Alzheimer's Disease: Novel Application of Mesenchymal Stem Cells and their Role in Hippocampal Neurogenesis

The neurogenesis can occur in two regions of the adult mammalian brain throughout the lifespan: the subgranular zone of the hippocampal dentate gyrus, and the subventricular zone of the lateral ventricle. The proliferation and maturation of neural progenitor cells are tightly regulated through intrinsic and extrinsic factors. The integration of maturated cells into the circuitry of the adult hippocampus emphasizes the importance of adult hippocampal neurogenesis in learning and memory. There is a large body of evidence demonstrating that alteration in the neurogenesis process in the adult hippocampus results in an early event in the course of Alzheimer's disease (AD). In AD condition, the number and maturation of neurons declines progressively in the hippocampus. Innovative therapies are required to modulate brain homeostasis. Mesenchymal stem cells (MSCs) hold an immense potential to regulate the neurogenesis process, and are currently tested in some brain-related disorders, such as AD. Therefore, the aim of this review is to discuss the use of MSCs to regulate endogenous adult neurogenesis and their significant impact on future strategies for the treatment of AD.

Adult neurogenesis and the molecular signalling pathways in brain: the role of stem cells in adult hippocampal neurogenesis

Molecular signalling pathways are an evolutionarily conserved multifaceted pathway that can control diverse cellular processes. The role of signalling pathways in regulating development and tissue homeostasis as well as hippocampal neurogenesis is needed to study in detail. In the adult brain, the Notch signalling pathway, in collaboration with the Wnt/β-catenin, bone morphogenetic proteins (BMPs), and sonic hedgehog (Shh) molecular signalling pathways, are involved in stem cell regulation in the hippocampal formation, and they also control the plasticity of the neural stem cells (NSCs) or neural progenitor cells (NPCs) which involved in neurogenesis processes. Here we discuss the distinctive roles of molecular signalling pathways involved in the generation of new neurons from a pool of NSCs in the adult brain. Our approach will facilitate the understanding of the molecular signalling mechanism of hippocampal neurogenesis during NSCs development in the adult brain using molecular aspects coupled with cell biological and physiological analysis.

Stem cell-based therapy as a promising approach in Alzheimer's disease: current perspectives on novel treatment

Alzheimer's disease (AD) is a neuronal disorder with insidious onset and slow progression, leading to growing global concern with huge implications for individuals and society. The occurrence of AD has been increased and has become an important health issue throughout the world. In recent years, the care of more than 35 million patients with AD costs over $ 600 billion per year, it is approximately 1 percent of the global Gross Domestic Product. Currently, the therapeutic approach is not effective for neurological deficits especially after the development of these major neurological disorders. The discovery of the technique called cell-based therapy has shown promising results and made important conclusions beyond AD using the stem cells approach. Here we review recent progress on stem cell-based therapy in the context of AD.