Exendin-4 gene modification and microscaffold encapsulation promote self-persistence and antidiabetic activity of MSCs

Engineered Macrophage Membrane-Camouflaged Nanodecoys Reshape the Infectious Microenvironment for Efficient Periodontitis Treatment

A vicious cycle between microbiota dysbiosis and hyperactivated inflammation, hardly disrupted by conventional therapies, remains a significant clinical challenge for periodontitis treatment. Herein, by cloaking a cascade catalysis system in an engineered macrophage membrane, a nanodecoy-based strategy, with targeted bacteria-killing and immunomodulatory abilities, is proposed for reshaping the hostile periodontitis microenvironment. Specifically, recombinant human antimicrobial peptide, LL-37, is anchored to a Toll-like receptor-enriched macrophage membrane via genetic engineering, which facilitates the specific bacteria elimination and efficient tissue retention of the nanodecoys. Moreover, the cascade catalysis system integrates L-amino acid oxidase (LAAO) with hollowed manganese dioxide (hMnO2) by reciprocal elevation of the catalytic efficiency of hMnO2 and LAAO, leading to accelerated O2 generation under a hypoxic microenvironment and disrupted metabolism of periodontopathogenic bacteria. Notably, the nanodecoys trigger the nuclear translocation of NF-E2-related factor-2 (NRF2) to reduce oxidative stress response and rewire the polarization of macrophages, thereby boosting the osteogenic differentiation of osteoblasts. Furthermore, the alveolar bone regeneration therapeutically benefits from the nanodecoys in vivo. Altogether, these results highlight the attractive functions of engineered macrophage membrane-cloaked nanodecoys for effective periodontitis treatment.

Engineered 3D mesenchymal stem cell aggregates with multifunctional prowess for bone regeneration: Current status and future prospects

BACKGROUND

Impaired efficacy of in vitro expanded mesenchymal stem cells (MSCs) is a universal and thorny situation, which cast a shadow on further clinical translation of exogenous MSCs. Moreover, the relatively lengthy healing process, host metabolic heterogeneity and the sophisticated cell recognition and crosstalk pose rigorous challenges towards MSC-based bone regeneration strategies. Three-dimensional (3D) cell aggregates facilitate more robust intercellular communications and cell-extracellular matrix (ECM) interactions, providing a better mimicry of microarchitectures and biochemical milieus in vivo, which is conducive for stemness maintenance and downstream bone formation.

AIM OF REVIEW

This review enunciates the phenotypic features of MSCs in aggregates, which deepens the knowledge of the MSC fate determination in 3D microenvironment. By summarizing current empowerment methods and biomaterial-combined techniques for establishing functionalized MSC aggregates, this review aims to spark innovative and promising solutions for exalting the translational value of MSCs and improve their therapeutic applications in bone tissue repair.

KEY SCIENTIFIC CONCEPTS OF REVIEW

3D aggregates optimize regenerative behaviors of in vitro cultured MSCs including cell adhesion, viability, proliferation, pluripotency and immunoregulation capacity, etc. Biomaterials hybridization endows MSC aggregates with tailored mechanical and biological properties, which offers more possibilities in adapting various clinical scenarios.

Knockout of B2M in combination with PD-L1 overexpression protects MSC-derived new islet β cells from graft rejection in the treatment of canine diabetes mellitus

BACKGROUND

The immunogenicity of allogeneic mesenchymal stem cells (MSCs) is significantly enhanced after transplantation or differentiation, and these cells can be recognized and cleared by recipient immune cells. Graft rejection has become a major obstacle to improving the therapeutic effect of allogeneic MSCs or, after their differentiation, transplantation in the treatment of diabetes and other diseases. Solving this problem is helpful for prolonging the time that cells play a role in the recipient body and for significantly improving the clinical therapeutic effect.

METHODS

In this study, canine adipose-derived mesenchymal stem cells (ADSCs) were used as seed cells, and gene editing technology was used to knock out the B2M gene in these cells and cooperate with the overexpression of the PD-L1 gene. Gene-edited ADSCs (GeADSCs), whose biological characteristics and safety are not different from those of normal canine ADSCs, have been obtained.

RESULTS

The immunogenicity of GeADSCs is reduced, the immune escape ability of GeADSCs is enhanced, and GeADSCs can remain in the body for a longer time. Using the optimized induction program, the efficiency of the differentiation of GeADSCs into new islet β-cells was increased, and the maturity of the new islet β-cells was increased. The immunogenicity of new islet β-cells decreased, and their immune escape ability was enhanced after the cells were transplanted into diabetic dogs (the graft site was prevascularized by the implantation of a scaffold to form a vascularized pouch). The number of infiltrating immune cells and the content of immune factors were decreased at the graft site.

CONCLUSIONS

New islet β-cell transplantation, which has low immunogenicity, can reverse diabetes in dogs, and the therapeutic effect of cell transplantation is significantly enhanced. This study provides a new method for prolonging the survival and functional time of cells in transplant recipients and significantly improving the clinical therapeutic effect.

Mesenchymal Stem Cells Engineered by Multicomponent Coassembled DNA Nanofibers for Enhanced Wound Healing

A major challenge for stem cell therapies, such as using mesenchymal stem cells to treat skin injuries, is the stable engraftment of exogenous cells and the maintenance of their regenerative capacities in the wound areas. DNA-based self-assembly strategies can be used for artificial and multifunctional cell surface engineering to stabilize and enhance their functions for therapeutic applications. Here, we developed DNA nanofiber-decorated stem cells, in which DNA-based, multivalent fiber-like structures were self-assembled in situ on the cell surfaces. These engineered stem cells have demonstrated robust reactive oxygen species (ROS) scavenging effects, specific adhesion to damaged vascular endothelial cells, and the ability to enhance angiogenesis, which were effective and safe for acute or chronic wound healing in a mouse model with excisional skin injury. This DNA nanostructure-engineered stem cell provides a novel therapeutic platform for the treatment of tissue damage.

Exendin-4-enriched exosomes from hUCMSCs alleviate diabetic nephropathy via gut microbiota and immune modulation

Introduction

Diabetic nephropathy (DN) presents a significant therapeutic challenge, compounded by complex pathophysiological mechanisms. Recent studies suggest Exendin-4 (Ex-4) as a potential ameliorative agent for DN, albeit with unclear mechanisms. This research investigates the effects and underlying mechanisms of Ex-4-enriched exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSCs) on DN, focusing on their renoprotective properties and interactions with gut microbiota.

Method

Exosomes from hUCMSCs (hUCMSCs-Exo) were loaded with Ex-4 via electroporation. A streptozotocin (STZ) -induced DN mouse model was employed to assess the therapeutic impact of these engineered exosomes. The study further explored immune cell dynamics, mainly CD4+ regulatory T (Treg) cells, using bioinformatics, flow cytometry, and the influence of gut microbiota through antibiotic treatment and specific bacterial reintroduction.

Results

Treatment with hUCMSCs-Exo@Ex-4 significantly improved key DN markers, including blood glucose and proteinuria, alleviating kidney damage. A notable decrease in natural Treg cell infiltration in DN was observed, while Ex-4-loaded exosomes promoted CD4+ Treg cell induction. The therapeutic benefits of hUCMSCs-Exo@Ex-4 were diminished upon CD4+ Treg cell depletion, underscoring their role in this context. Notably, CD4+ Treg cell induction correlated with the presence of Prevotella species, and disruption of gut microbiota adversely affected these cells and the therapeutic efficacy of the treatment. However, the reintroduction of Prevotella strains counteracted these adverse effects.

Discussion

This study elucidates a novel therapeutic mechanism of Ex-4-loaded hUCMSCs exosomes in DN, highlighting the induction of CD4+ Treg cells mediated by specific gut microbiota components. These findings underscore the potential of leveraging gut microbiota and immune cell interplay in developing effective DN treatments.

Optimization strategies for mesenchymal stem cell-based analgesia therapy: a promising therapy for pain management

Pain is a very common and complex medical problem that has a serious impact on individuals' physical and mental health as well as society. Non-steroidal anti-inflammatory drugs and opioids are currently the main drugs used for pain management, but they are not effective in controlling all types of pain, and their long-term use can cause adverse effects that significantly impair patients' quality of life. Mesenchymal stem cells (MSCs) have shown great potential in pain treatment. However, limitations such as the low proliferation rate of MSCs in vitro and low survival rate in vivo restrict their analgesic efficacy and clinical translation. In recent years, researchers have explored various innovative approaches to improve the therapeutic effectiveness of MSCs in pain treatment. This article reviews the latest research progress of MSCs in pain treatment, with a focus on methods to enhance the analgesic efficacy of MSCs, including engineering strategies to optimize the in vitro culture environment of MSCs and to improve the in vivo delivery efficiency of MSCs. We also discuss the unresolved issues to be explored in future MSCs and pain research and the challenges faced by the clinical translation of MSC therapy, aiming to promote the optimization and clinical translation of MSC-based analgesia therapy.

Human Menstrual Blood-Derived Stem Cells Protect against Tacrolimus-Induced Islet Dysfunction via Cystathionine β-Synthase Mediated IL-6/STAT3 Inactivation

Diabetes imposes a huge burden worldwide. Islet transplantation is an alternative therapy for diabetes. However, tacrolimus, a kind of immunosuppressant after organ transplantation, is closely related to post-transplant diabetes mellitus. Mesenchymal stem cells (MSCs) have attracted interest for their potential to alleviate diabetes. In vivo experiments revealed that human menstrual blood-derived stem cells (MenSCs) treatment improved tacrolimus-induced blood glucose, body weight, and glucose tolerance disorders in mice. RNA sequencing was used to analyze the potential therapeutic targets of MenSCs. In this study, we illustrated that cystathionine β-synthase (CBS) contributed to tacrolimus -induced islet dysfunction. Using β-cell lines (MIN6, β-TC-6), we demonstrated that MenSCs ameliorated tacrolimus-induced islet dysfunction in vitro. Moreover, MenSC reduced the tacrolimus-induced elevation of CBS levels and significantly enhanced the viability, anti-apoptotic ability, glucose-stimulated insulin secretion (GSIS), and glycolytic flux of β-cells. We further revealed that MenSCs exerted their therapeutic effects by inhibiting CBS expression to activate the IL6/JAK2/STAT3 pathway. In conclusion, we showed that MenSCs may be a potential strategy to improve tacrolimus-induced islet dysfunction.

Potential molecular and cellular mechanisms of the effects of cuproptosis-related genes in the cardiomyocytes of patients with diabetic heart failure: a bioinformatics analysis

Background

Diabetes mellitus is an independent risk factor for heart failure, and diabetes-induced heart failure severely affects patients' health and quality of life. Cuproptosis is a newly defined type of programmed cell death that is thought to be involved in the pathogenesis and progression of cardiovascular disease, but the molecular mechanisms involved are not well understood. Therefore, we aimed to identify biomarkers associated with cuproptosis in diabetes mellitus-associated heart failure and the potential pathological mechanisms in cardiomyocytes.

Materials

Cuproptosis-associated genes were identified from the previous publication. The GSE26887 dataset was downloaded from the GEO database.

Methods

The consistency clustering was performed according to the cuproptosis gene expression. Differentially expressed genes were identified using the limma package, key genes were identified using the weighted gene co-expression network analysis(WGCNA) method, and these were subjected to immune infiltration analysis, enrichment analysis, and prediction of the key associated transcription factors. Consistency clustering identified three cuproptosis clusters. The differentially expressed genes for each were identified using limma and the most critical MEantiquewhite4 module was obtained using WGCNA. We then evaluated the intersection of the MEantiquewhite4 output with the three clusters, and obtained the key genes.

Results

There were four key genes: HSDL2, BCO2, CORIN, and SNORA80E. HSDL2, BCO2, and CORIN were negatively associated with multiple immune factors, while SNORA80E was positively associated, and T-cells accounted for a major proportion of this relationship with the immune system. Four enriched pathways were found to be associated: arachidonic acid metabolism, peroxisomes, fatty acid metabolism, and dorsoventral axis formation, which may be regulated by the transcription factor MECOM, through a change in protein structure.

Conclusion

HSDL2, BCO2, CORIN, and SNORA80E may regulate cardiomyocyte cuproptosis in patients with diabetes mellitus-associated heart failure through effects on the immune system. The product of the cuproptosis-associated gene LOXL2 is probably involved in myocardial fibrosis in patients with diabetes, which leads to the development of cardiac insufficiency.

Enhanced bone regeneration via endochondral ossification using Exendin-4-modified mesenchymal stem cells

Nonunions and delayed unions pose significant challenges in orthopedic treatment, with current therapies often proving inadequate. Bone tissue engineering (BTE), particularly through endochondral ossification (ECO), emerges as a promising strategy for addressing critical bone defects. This study introduces mesenchymal stem cells overexpressing Exendin-4 (MSC-E4), designed to modulate bone remodeling via their autocrine and paracrine functions. We established a type I collagen (Col-I) sponge-based in vitro model that effectively recapitulates the ECO pathway. MSC-E4 demonstrated superior chondrogenic and hypertrophic differentiation and enhanced the ECO cell fate in single-cell sequencing analysis. Furthermore, MSC-E4 encapsulated in microscaffold, effectively facilitated bone regeneration in a rat calvarial defect model, underscoring its potential as a therapeutic agent for bone regeneration. Our findings advocate for MSC-E4 within a BTE framework as a novel and potent approach for treating significant bone defects, leveraging the intrinsic ECO process.

Hybrid gelatin-ascorbyl phosphate scaffolds accelerate diabetic wound healing via ROS scavenging, angiogenesis and collagen remodeling

Skin wound healing, particularly diabetic wound healing, is challenging in clinical management. Impaired wound healing is associated with persistent oxidative stress, altered inflammatory responses, unsatisfactory angiogenesis and epithelialization. Magnesium ascorbyl phosphate (MAP), which is an ascorbic acid derivative and active ingredient in cosmetics, has been reported to scavenge reactive oxygen species (ROS), and is considered a potential therapeutic agent for diabetic wounds. Herein, we report a hybrid gelatin-MAP scaffolds that can reduces oxidative stress damage, enhances angiogenesis and collagen remodeling to accelerate diabetic wound repair. Preliminary insights based on network pharmacology indicate that MAP may accelerate wound repair through multiple biological pathways, including extracellular matrix remodeling and anti-apoptosis. In vitro studies showed that the hybrid hydrogel scaffold had suitable mechanical properties, excellent biocompatibility and bioactivity. Further animal experiments demonstrated that the hydrogel accelerated full-thickness wound repair in diabetic mice (repair rate MAP vs Control=91.791±3.306 % vs 62.962±6.758 %) through antioxidant, neuroangiogenesis, collagen remodeling, and up-regulated the expression of the related factors COL-1, CD31, VEGF, and CGRP. Overall, we developed a bioactive hybrid hydrogel encapsulating MAP that synergistically promotes diabetic wound repair through multiple biological effects. This potentially integrated therapeutic scaffold may enrich future surgical approaches for treating diabetic wounds.

Chondrocyte membrane-coated nanoparticles promote drug retention and halt cartilage damage in rat and canine osteoarthritis

Osteoarthritis (OA) is a chronic joint disease characterized by progressive degeneration of articular cartilage. A challenge in the development of disease-modifying drugs is effective delivery to chondrocytes. The unique structure of the joint promotes rapid clearance of drugs through synovial fluid, and the dense and avascular cartilage extracellular matrix (ECM) limits drug penetration. Here, we show that poly(lactide-co-glycolic acid) nanoparticles coated in chondrocyte membranes (CM-NPs) were preferentially taken up by rat chondrocytes ex vivo compared with uncoated nanoparticles. Internalization of the CM-NPs was mediated primarily by E-cadherin, clathrin-mediated endocytosis, and micropinocytosis. These CM-NPs adhered to the cartilage ECM in rat knee joints in vivo and penetrated deeply into the cartilage matrix with a residence time of more than 34 days. Simulated synovial fluid clearance studies showed that CM-NPs loaded with a Wnt pathway inhibitor, adavivint (CM-NPs-Ada), delayed the catabolic metabolism of rat and human chondrocytes and cartilage explants under inflammatory conditions. In a surgical model of rat OA, drug-loaded CM-NPs effectively restored gait, attenuated periarticular bone remodeling, and provided chondroprotection against cartilage degeneration. OA progression was also mitigated by CM-NPs-Ada in a canine model of anterior cruciate ligament transection. These results demonstrate the feasibility of using chondrocyte membrane-coated nanoparticles to improve the pharmacokinetics and efficacy of anti-OA drugs.

Enhancing the therapeutic efficacy of mesenchymal stem cell transplantation in diabetes: Amelioration of mitochondrial dysfunction-induced senescence

Mesenchymal stem cell (MSC) transplantation offers significant potential for the treatment of diabetes mellitus (DM) and its complications. However, hyperglycemic conditions can induce senescence and dysfunction in both transplanted and resident MSCs, thereby limiting their therapeutic potential. Mitochondrial dysfunction and oxidative stress are key contributors to this process in MSCs exposed to hyperglycemia. As such, strategies aimed at mitigating mitochondrial dysfunction could enhance the therapeutic efficacy of MSC transplantation in DM. In this review, we provide an updated overview of how mitochondrial dysfunction mediates MSC senescence. We present experimental evidence for the molecular mechanisms behind high glucose-induced mitochondrial dysfunction in MSCs, which include impairment of mitochondrial biogenesis, mitochondrial calcium regulation, the mitochondrial antioxidant system, mitochondrial fusion-fission dynamics, mitophagy, and intercellular mitochondrial transfer. Furthermore, we propose potential pharmacological candidates that could improve the efficacy of MSC transplantation by enhancing mitochondrial function in patients with DM and related complications.

Genetically engineered mesenchymal stem cells as a nitric oxide reservoir for acute kidney injury therapy

Nitric oxide (NO), as a gaseous therapeutic agent, shows great potential for the treatment of many kinds of diseases. Although various NO delivery systems have emerged, the immunogenicity and long-term toxicity of artificial carriers hinder the potential clinical translation of these gas therapeutics. Mesenchymal stem cells (MSCs), with the capacities of self-renewal, differentiation, and low immunogenicity, have been used as living carriers. However, MSCs as gaseous signaling molecule (GSM) carriers have not been reported. In this study, human MSCs were genetically modified to produce mutant β-galactosidase (β-GALH363A). Furthermore, a new NO prodrug, 6-methyl-galactose-benzyl-oxy NONOate (MGP), was designed. MGP can enter cells and selectively trigger NO release from genetically engineered MSCs (eMSCs) in the presence of β-GALH363A. Moreover, our results revealed that eMSCs can release NO when MGP is systemically administered in a mouse model of acute kidney injury (AKI), which can achieve NO release in a precise spatiotemporal manner and augment the therapeutic efficiency of MSCs. This eMSC and NO prodrug system provides a unique and tunable platform for GSM delivery and holds promise for regenerative therapy by enhancing the therapeutic efficiency of stem cells.

Expansion of human megakaryocyte-biased hematopoietic stem cells by biomimetic Microniche

Limited numbers of available hematopoietic stem cells (HSCs) limit the widespread use of HSC-based therapies. Expansion systems for functional heterogenous HSCs remain to be optimized. Here, we present a convenient strategy for human HSC expansion based on a biomimetic Microniche. After demonstrating the expansion of HSC from different sources, we find that our Microniche-based system expands the therapeutically attractive megakaryocyte-biased HSC. We demonstrate scalable HSC expansion by applying this strategy in a stirred bioreactor. Moreover, we identify that the functional human megakaryocyte-biased HSCs are enriched in the CD34⁺CD38^-CD45RA-CD90⁺CD49f ^lowCD62L^-CD133⁺ subpopulation. Specifically, the expansion of megakaryocyte-biased HSCs is supported by a biomimetic niche-like microenvironment, which generates a suitable cytokine milieu and supplies the appropriate physical scaffolding. Thus, beyond clarifying the existence and immuno-phenotype of human megakaryocyte-biased HSC, our study demonstrates a flexible human HSC expansion strategy that could help realize the strong clinical promise of HSC-based therapies.

Injectable bone marrow microniches by co-culture of HSPCs with MSCs in 3D microscaffolds promote hematopoietic reconstitution from acute lethal radiation

Hematopoietic syndrome of acute radiation syndrome (h-ARS) is an acute illness resulted from the damage of bone marrow (BM) microenvironment after exposure to radiation. Currently, the clinical management of h-ARS is limited to medication-assisted treatment, while there is still no specific therapy for the hematopoietic injury from high-dose radiation exposure. Our study aimed to assemble biomimetic three-dimensional (3D) BM microniches by co-culture of hematopoietic stem and progenitor cells (HSPCs) and mesenchymal stem cells (MSCs) in porous, injectable and viscoelastic microscaffolds in vitro. The biodegradable BM microniches were then transplanted in vivo into the BM cavity for the treatment of h-ARS. We demonstrated that the maintenance of HSPCs was prolonged by co-culture with MSCs in the porous 3D microscaffolds with 84 μm in pore diameter and 11.2 kPa in Young's modulus compared with 2D co-culture system. Besides, the minimal effective dose and therapeutic effects of the BM microniches were investigated on a murine model of h-ARS, which showed that the intramedullary cavity-injected BM microniches could adequately promote hematopoietic reconstitution and mitigate death from acute lethal radiation with a dose as low as 1000 HSPCs. Furthermore, the mRNA expression of Notch1 and its downstream target gene Hes1 of HSPCs were increased when co-cultured with MSCs, while the Jagged1 expression of the co-cultured MSCs was upregulated, indicating the significance of Notch signaling pathway in maintenance of HSPCs. Collectively, our findings provide evidence that biomimetic and injectable 3D BM microniches could maintain HSPCs, promote hematopoiesis regeneration and alleviate post-radiation injury, which provides a promising approach to renovate conventional HSPCs transplantation for clinical treatment of blood and immune disorders.

Global research trends in extracellular vesicles based on stem cells from 1991 to 2021: A bibliometric and visualized study

Objective: With the development of extracellular vesicles (EVs) based on stem cells research all over the world, our present study was aiming to discover the global trends in this field. Methods: All publications related to EVs based on stem cells from 1991 to 2021 were collected from the Science Citation Index-Expanded of Web of Science Subsequently, the data were evaluated using the bibliometric methodology. In terms of visualized study, the VOS viewer software was performed to investigate the bibliographic coupling, co-citation, co-authorship, and co-occurrence trends, and last for the publication's trends involved in the field of EVs based on stem cells. Results: A total of 8,208 publications were retrieved and the relative number of global publications and research interests were increasing every year especially in recent 5 years. China rank top one in terms of total publications, prolific authors, and funds, whereas the USA made the greatest contributions with the most total citations and highest H-index to the global research. Stem cell research therapy contributed the highest publications, whereas the journal of PLOS ONE showed the best total link strength. The Shanghai Jiao Tong University, University of California System, and Harvard University were the most contributive institutions. The global studies could be divided into six clusters as follows: cancer research, musculoskeletal system research, respiratory system research, urinary system and endocrine system research, nerve system research, and cardiovascular system research. All the directions were predicted to still hotspots in near future researches in this field. Conclusion: The total number of publications about EVs based stem cells would be increasing according to the current global trends. China and the USA was the largest contributors in this field. Further efforts should be put in the directions of cancer research, musculoskeletal system research, respiratory system research, urinary system and endocrine system research, nerve system research, as well was cardiovascular system research in this field of EVs based stem cells.

Mesenchymal Stem Cells (MSCs): A Novel Therapy for Type 2 Diabetes

Although plenty of drugs are currently available for type 2 diabetes mellitus (T2DM), a subset of patients still failed to restore normoglycemia. Recent studies proved that symptoms of T2DM patients who are unresponsive to conventional medications could be relieved with mesenchymal stem/stromal cell (MSC) therapy. However, the lack of systematic summary and analysis for animal and clinical studies of T2DM has limited the establishment of standard guidelines in anti-T2DM MSC therapy. Besides, the therapeutic mechanisms of MSCs to combat T2DM have not been thoroughly understood. In this review, we present an overview of the current status of MSC therapy in treating T2DM for both animal studies and clinical studies. Potential mechanisms of MSC-based intervention on multiple pathological processes of T2DM, such as β-cell exhaustion, hepatic dysfunction, insulin resistance, and systemic inflammation, are also delineated. Moreover, we highlight the importance of understanding the pharmacokinetics (PK) of transplanted cells and discuss the hurdles in MSC-based T2DM therapy toward future clinical applications.

Biomaterials to enhance stem cell transplantation

The successful transplantation of stem cells has the potential to transform regenerative medicine approaches and open promising avenues to repair, replace, and regenerate diseased, damaged, or aged tissues. However, pre-/post-transplantation issues of poor cell survival, retention, cell fate regulation, and insufficient integration with host tissues constitute significant challenges. The success of stem cell transplantation depends upon the coordinated sequence of stem cell renewal, specific lineage differentiation, assembly, and maintenance of long-term function. Advances in biomaterials can improve pre-/post-transplantation outcomes by integrating biophysiochemical cues and emulating tissue microenvironments. This review highlights leading biomaterials-based approaches for enhancing stem cell transplantation.

Biochemical Functions and Clinical Characterizations of the Sirtuins in Diabetes-Induced Retinal Pathologies

Diabetic retinopathy (DR) is undoubtedly one of the most prominent causes of blindness worldwide. This pathology is the most frequent microvascular complication arising from diabetes, and its incidence is increasing at a constant pace. To date, the insurgence of DR is thought to be the consequence of the intricate complex of relations connecting inflammation, the generation of free oxygen species, and the consequent oxidative stress determined by protracted hyperglycemia. The sirtuin (SIRT) family comprises 7 histone and non-histone protein deacetylases and mono (ADP-ribosyl) transferases regulating different processes, including metabolism, senescence, DNA maintenance, and cell cycle regulation. These enzymes are involved in the development of various diseases such as neurodegeneration, cardiovascular pathologies, metabolic disorders, and cancer. SIRT1, 3, 5, and 6 are key enzymes in DR since they modulate glucose metabolism, insulin sensitivity, and inflammation. Currently, indirect and direct activators of SIRTs (such as antagomir, glycyrrhizin, and resveratrol) are being developed to modulate the inflammation response arising during DR. In this review, we aim to illustrate the most important inflammatory and metabolic pathways connecting SIRT activity to DR, and to describe the most relevant SIRT activators that might be proposed as new therapeutics to treat DR.

Inflammation-Stimulated MSC-Derived Small Extracellular Vesicle miR-27b-3p Regulates Macrophages by Targeting CSF-1 to Promote Temporomandibular Joint Condylar Regeneration

Small extracellular vesicles (sEVs) secreted by mesenchymal stem cells (MSCs) have been extensively studied in recent years. sEV contents change with the secreting cell state. When MSCs are exposed to an inflammatory environment, they release more functional growth factors, exosomes, and chemokines. Herein, MSCs are stimulated to alter sEV cargos and functions to regulate the inflammatory microenvironment and promote tissue regeneration. Sequencing of sEV miRNAs shows that certain RNAs conducive to cell function are upregulated. In this study, in vitro cell function experiments show that both inflammation-stimulated adipose-derived MSC (ADSC)-derived sEV (IAE) and normal ADSC-derived sEV (AE) promote cell proliferation; IAE also significantly improves cell migration. Regarding macrophage polarization regulation, IAE significantly promotes M2 macrophage differentiation. RNA-sequencing analysis indicates that high miR-27b-3p expression levels in IAE may regulate macrophages by targeting macrophage colony-stimulating factor-1 (CSF-1). In vivo, a rabbit temporomandibular joint (TMJ) condylar osteochondral defect model shows that both AE and IAE promote TMJ regeneration, with IAE having the most significant therapeutic effect. Therefore, the authors confirm that exposing MSCs to an inflammatory environment can feasibly enhance sEV functions and that modified sEVs achieve better therapeutic effects.

Comparative Analysis of the Therapeutic Effects of Amniotic Membrane and Umbilical Cord Derived Mesenchymal Stem Cells for the Treatment of Type 2 Diabetes

Type 2 diabetes mellitus (T2DM), one of the most common carbohydrate metabolism disorders, is characterized by chronic hyperglycemia and insulin resistance (IR), and has become an urgent global health challenge. Mesenchymal stem cells (MSCs) originating from perinatal tissues such as umbilical cord (UC) and amniotic membrane (AM) serve as ideal candidates for the treatment of T2DM due to their great advantages in terms of abundant source, proliferation capacity, immunomodulation and plasticity for insulin-producing cell differentiation. However, the optimally perinatal MSC source to treat T2DM remains elusive. This study aims to compare the therapeutic efficacy of MSCs derived from AM and UC (AMMSCs and UCMSCs) of the same donor in the alleviation of T2DM symptoms and explore the underlying mechanisms. Our results showed that AMMSCs and UCMSCs displayed indistinguishable immunophenotype and multi-lineage differentiation potential, but UCMSCs had a much higher expansion capacity than AMMSCs. Moreover, we uncovered that single-dose intravenous injection of either AMMSCs or UCMSCs could comparably reduce hyperglycemia and improve IR in T2DM db/db mice. Mechanistic investigations revealed that either AMMSC or UCMSC infusion could greatly improve glycolipid metabolism in the liver of db/db mice, which was evidenced by decreased liver to body weight ratio, reduced lipid accumulation, upregulated glycogen synthesis, and increased Akt phosphorylation. Taken together, these data indicate that the same donor-derived AMMSCs and UCMSCs possessed comparable effects and shared a similar hepatoprotective mechanism on the alleviation of T2DM symptoms.