The bone marrow-derived mesenchymal stem cells (BMSCs) alleviate diabetic peripheral neuropathy induced by STZ via activating GSK-3β/β-catenin signaling pathway

Evaluating the efficacy of mesenchymal stem cells for diabetic neuropathy: A systematic review and meta-analysis of preclinical studies

Diabetic neuropathy affects nearly half of all diabetics and poses a significant threat to public health. Recent preclinical studies suggest that mesenchymal stem cells (MSCs) may represent a promising solution for the treatment of diabetic neuropathy. However, an objective assessment of the preclinical effectiveness of MSCs is still pending. We conducted a comprehensive search of PubMed, Web of Science, Embase, and Cochrane library to identify preclinical studies that investigate the effects of MSCs on diabetic neuropathy up until 15 September 2023. Outcome indicators consisted of motor and sensory nerve conduction velocities, intra-epidermal nerve fiber density, sciatic nerve blood flow, capillary-to-muscle fiber ratio, neurotrophic factors, angiogenic factors and inflammatory cytokines. The literature review and meta-analysis were conducted independently by two researchers. 23 studies that met the inclusion criteria were included in this system review for qualitative and quantitative analysis. Pooled analyses indicated that MSCs exhibited an evident benefit in diabetic neuropathy in terms of motor (SMD = 2.16, 95% CI: 1.71-2.61) and sensory nerve conduction velocities (SMD = 2.93, 95% CI: 1.78-4.07), intra-epidermal nerve fiber density (SMD = 3.17, 95% CI: 2.28-4.07), sciatic nerve blood flow (SMD = 2.02, 95% CI: 1.37-2.66), and capillary-to-muscle fiber ratio (SMD = 2.28, 95% CI: 1.55 to 3.01, p < 0.00001). Furthermore, after MSC therapy, the expressions of neurotrophic and angiogenic factors increased significantly in most studies, while the levels of inflammatory cytokines were significantly reduced. The relevance of this review relies on the fact that summarizes an extensive body of work entailing substantial preclinical evidence that supports the efficacy of MSCs in mitigating diabetic neuropathy. While MSCs emerge as a promising potential treatment for diabetic neuropathy, further research is essential to elucidate the underlying mechanisms and the best administration strategy for MSCs.

Stem cells as a regenerative medicine approach in treatment of microvascular diabetic complications

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by high blood glucose and is associated with high morbidity and mortality among the diabetic population. Uncontrolled chronic hyperglycaemia causes increased formation and accumulation of different oxidative and nitrosative stress markers, resulting in microvascular and macrovascular complications, which might seriously affect the quality of a patient's life. Conventional treatment strategies are confined to controlling blood glucose by regulating the insulin level and are not involved in attenuating the life-threatening complications of diabetes mellitus. Thus, there is an unmet need to develop a viable treatment strategy that could target the multi-etiological factors involved in the pathogenesis of diabetic complications. Stem cell therapy, a regenerative medicine approach, has been investigated in diabetic complications owing to their unique characteristic features of self-renewal, multilineage differentiation and regeneration potential. The present review is focused on potential therapeutic applications of stem cells in the treatment of microvascular diabetic complications such as nephropathy, retinopathy, and polyneuropathy.

Research Progress on Mesenchymal Stem Cells for the Treatment of Diabetes and Its Complications

Diabetes mellitus (DM) is a chronic disease that threatens human health. Although many drugs are available to treat DM, various complications caused by DM are unavoidable. As an emerging treatment for DM, mesenchymal stem cells (MSCs) have shown many advantages and are gradually gaining public attention. This review summarizes the clinical studies on the use of MSCs to treat DM and the potential mechanisms of complications such as pancreatic dysfunction, cardiovascular lesions, renal lesions, neurological lesions, and trauma repair. This review focuses on the research progress on MSC-mediated secretion of cytokines, improvements in the microenvironment, repair of tissue morphology, and related signaling pathways. At present, the sample sizes in clinical studies of MSCs in treating DM are small, and there is a lack of standardized quality control systems in the preparation, transportation, and infusion methods, so we need to conduct more in-depth studies. In conclusion, MSCs have shown superior potential for use in the treatment of DM and its complications and will hopefully become a novel therapeutic approach in the future.

Human Placenta-Derived Mesenchymal Stem Cells Ameliorate Diabetic Neuropathy via Wnt Signaling Pathway

OBJECTIVES

To investigate the effect of placenta-derived mesenchymal stem cells (PMSCs) on diabetic peripheral neuropathy and explore the role of Wnt signaling pathway.

METHOD

Twenty-seven male db/db mice were randomly categorized into the control group, PMSC group, and PMSC treatment with Wnt inhibitor treatment group. Intervention was initiated in week 22. Thermal stimulation response was determined with a plantar analgesia tester. The mice were sacrificed on 7, 14, and 28 days. The morphology of sciatic nerves was observed by electron microscopy, and the expression of protein gene product (PGP) 9.5, S100β, and Ku80 was detected by immunofluorescence. Bax, β-catenin, and dishevelled1 (DVL1) were detected by western blot.

RESULTS

Thermal stimulation response was improved in the PMSC group on 14 and 28 days. Compared with the control group, PGP9.5 was increased in the PMSC group, accompanied by a significant increase in the expression of S100β. On the contrary, LGK974 inhibited the effect of PMSCs on thermal stimulation response and the expression of PGP9.5 and S100β. Both PGP9.5 and S100β were correlated with Ku80 in fluorescence colocalization. The myelin sheath of sciatic nerves in the PMSC group was uniform and dense compared with that in the control group. The effects of PMSCs promoting myelin repair were significantly inhibited in the PMSC+LGK974 group. Bax in the PMSC group expressed less than the control group. In contrast, the expressions of β-catenin and DVL1 were higher compared with that in the control group on the 14th and 28th days. The expression of DVL1 and β-catenin was lower in the PMSC+LGK974 group than in the PMSC group.

CONCLUSIONS

PMSCs improved the symptoms of diabetic peripheral neuropathy, along with the improvement of nerve myelin lesions, promotion of nerve regeneration, and activation of Schwann cells, which might be related to the regulation of Wnt signaling pathway and inhibition of apoptosis.

MicroRNA-1592 in the Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Inhibits the Glioma Development In Vivo and In Vitro

This study evaluated the role of miRNA-1592 (miR-1592) carried by exosomes that originated from bone marrow mesenchymal stem cell (BMSC) in glioma. BMSCs were cultured and identified, followed by being co-cultured with glioma cells to measure cell invasion, metastasis, and apoptosis by transwell assay and flow cytometry, cell proliferation by MTT, PI3K/AKT signal protein expression by western blot. BMSC-originated exosomes with different concentrations were used as a treatment strategy for established tumor models. The tumor volume was measured and tumor tissues were harvested for immunohistochemistry and immunoblot analysis. After co-culture with BMSC-originated exosomes, glioma cells showed an up-regulated transcription of miR-1592, along with inhibited phosphorylation and activation of PI3K/AKT signal pathway. Moreover, glioma cells exhibited reduced migration and invasiveness In Vitro, which was accompanied by diminished levels of proteins involved in cellular invasiveness. Simultaneously, co-culture with BMSC-originated exosomes can restrain glioma cell proliferation via facilitating cell apoptosis In Vivo and In Vitro. In conclusion, exosome-encapsulated microRNA-1592 from BMSCs can suppress the In Vivo and In Vitro development of glioma through interfering with PI3K/AKT signaling pathway.

Exosomal MicroRNA-328 from Bone Marrow Mesenchymal Stem Cells (BMSCs) Alleviates Acute Lung Injury Through Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase (MAPK/ERK) Pathway

To elucidate the communication between exosomes (exo) derived from BMSCs and injured lung cells. BMSC-exo was isolated and characterized. Lung epithelial cells A549 were incubated with BMSC-exo, and treated by LPS to induce cell damage. CCK-8 assay was carried out to test cell proliferation, flow cytometry was adopted to analyze cell apoptosis, and RT-qPCR as well as Western blot analysis were selected to assess expression of apoptosis- and anti-apoptosis related proteins. Functional experiment was performed to identify the role of microRNA (miRNA)-328 in lung injury. LPS treatment significantly inhibited the viability of A549 cells, induced apoptosis of A549 cells by increasing Bax and casepase-3 levels and reducing Bcl-2 expression, whilst declined expression of miR-328 and suppressed the phosphorylation activation of the MAPK/ERK pathway. Meanwhile, the amount of IL-6, IL-1β and TNF-α were elevated in injured cells, but, the presence of BMSC-exo eliminated the elevation of the contents. Importantly, treatment with BMSC-exo increased miR-328 expression, activated MAPK MAPK/ERK pathway, inhibited apoptosis, and enhanced cell proliferation. However, the effect of BMSC-exo was attenuated when the cells were silenced for miR-328 expression. Collectively, BMSC-exo enriched miR-328 could relieve acute lung injury through MAPK/ERK pathway.

Mechanistic investigations of diabetic ocular surface diseases

With the global prevalence of diabetes mellitus over recent decades, more patients suffered from various diabetic complications, including diabetic ocular surface diseases that may seriously affect the quality of life and even vision sight. The major diabetic ocular surface diseases include diabetic keratopathy and dry eye. Diabetic keratopathy is characterized with the delayed corneal epithelial wound healing, reduced corneal nerve density, decreased corneal sensation and feeling of burning or dryness. Diabetic dry eye is manifested as the reduction of tear secretion accompanied with the ocular discomfort. The early clinical symptoms include dry eye and corneal nerve degeneration, suggesting the early diagnosis should be focused on the examination of confocal microscopy and dry eye symptoms. The pathogenesis of diabetic keratopathy involves the accumulation of advanced glycation end-products, impaired neurotrophic innervations and limbal stem cell function, and dysregulated growth factor signaling, and inflammation alterations. Diabetic dry eye may be associated with the abnormal mitochondrial metabolism of lacrimal gland caused by the overactivation of sympathetic nervous system. Considering the important roles of the dense innervations in the homeostatic maintenance of cornea and lacrimal gland, further studies on the neuroepithelial and neuroimmune interactions will reveal the predominant pathogenic mechanisms and develop the targeting intervention strategies of diabetic ocular surface complications.

MicroRNA-3100 from Bone Marrow Mesenchymal Stem Cells (BMSCs) Exosomes Alleviates Autoimmune Arthritis in Mice via Regulating Forkhead Box P3 Acetylase

To study the effect and mechanism of microRNA-3100 from exosome of BMSCs on autoimmune arthritis in mice. CIA mice model was established and treated with BMSCs exosomes or DMSO. The expression of Foxp3 was detected by PCR and Western blot. The Treg/Th17 population of T cells and the expression of related inflammatory factors were analyzed by flow cytometry. BMSCs trans-fected with MicroRNA-3100 inhibitor or MicroRNA-3100 was used to treat CIA mice through intravenous injection. The levels of Foxp3 and its acetylation, Treg/Th17 differentiation and inflammatory factors were detected, and the synovial tissues of mice were collected for analysis of its inflammatory infiltration. RA rats exhibited down-regulated Treg population and increased Th17 population in PBMC and SF, accompanied by reduced Foxp3 and acetylated Foxp3 expression, suppressed Tip60 expression in SF, in relative to normal control. However, exosomes of BMSCs administration recovered the changes. Further result showed that exosomes from BMSCs was enriched for miR-3100. miR-3100 inhibitor exposed CD4+ T cell exhibited reduced Tip60 and acetylated-Foxp3 expression, decreased Tregs population and increased Th17 cell population, vice versa as the miR-3100 mimics does. In addition, Tip60 inhibitors NU905 exerted the same effect as miR-3100 inhibitor transfection dose. Finally, miR-3100 overexpression could significantly reduce inflammation and immune cell infiltration, correct the dysfunction between Th17 and Tregs, recovered Tip60 and acetylation Foxp3 expression. MiRNA-3100 is enriched in exosomes of BMSCs, and can up-regulatethe expression of Foxp3, acetylated Foxp3 and Tip60 level, improving the imbalance of Treg/Th17 ratio, and improve autoimmune arthritis in mice.

Mesenchymal stem cells-derived extracellular vesicles ameliorate Alzheimer's disease in rat models via the microRNA-29c-3p/BACE1 axis and the Wnt/β-catenin pathway

Currently, Alzheimer's disease (AD) cannot be treated effectively. Mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) (MSC-EVs) exhibit therapeutic effects on many diseases. This study investigated the mechanism of bone marrow MSC-EVs (BM-MSC-EVs) in a rat model of AD. The cognitive function, amyloid-β (Aβ) plaques, Aβ deposition areas and levels of Aβ1-42, Aβ decomposition-related factors (NEP and IDE), and inflammatory cytokines in BM-MSC-EVs-treated AD rats were measured. The effect of BM-MSC-EVs was studied in AD neuron model. microRNA (miR)-29c-3p and BACE1 expression, as well as levels of Wnt/β-catenin pathway-related factors in AD and EVs-treated AD models were detected. miR-29c-3p relationship with BACE1 was predicted and confirmed. miR-29c-3p and BACE1 were interfered to verify the mechanism of EVs in AD. The Wnt/β-catenin pathway inhibitor DKK1 was further added to EVs-treated AD neurons. BM-MSC-EVs showed therapeutic effects on AD rats and neurons. BM-MSC-EVs carried miR-29c-3p into AD neurons. miR-29c-3p targeted BACE1. Silencing miR-29c-3p in BM-MSCs reduced BM-MSC-EV therapeutic effect on AD, which was reversed after BACE1 knockdown. miR-29c-3p targeted BACE1 and activated the Wnt/β-catenin pathway, and the Wnt/β-catenin pathway inhibition impaired EV therapeutic effects on AD. We highlighted that BM-MSC-EVs delivered miR-29c-3p to neurons to inhibit BACE1 expression and activate the Wnt/β-catenin pathway, thereby playing a therapeutic role in AD. This study may provide a novel perspective for elucidating the mechanism of MSCs in the treatment of AD.