Mesenchymal Stem Cells-derived Exosomes Ameliorate Lupus by Inducing M2 Macrophage Polarization and Regulatory T Cell Expansion in MRL/lpr Mice

Urine-derived stem cells from patients alleviate lupus nephritis via regulating macrophage polarization in a CXCL14-dependent manner

AIM

Mesenchymal stem cells (MSC) exhibit hopeful therapeutic potential for the treatment of lupus nephritis (LN). Nevertheless, most MSC are harvested invasively and only transplantation of allogeneic MSC takes effect. Urine-derived stem cells (USC) can be obtained by noninvasive and safe access. Whether USC can be used for autologous stem cell transplantation to treat LN remains unknown.

MATERIALS AND METHODS

USC were harvested from healthy individuals, systemic lupus erythematosus (SLE) patients with no LN (NLN) and LN patients. The biological characteristics and immunomodulatory ability of three USC types were compared. Therapeutic value of USC for LN in MRL/lpr mice and influence of USC on macrophages were assessed. We further explored the mechanism of USC from LN patients (LN-USC) on macrophage polarization.

KEY FINDINGS

LN-USC exhibited faster proliferation and less apoptosis, significantly upregulated regulatory T cells (Treg) and downregulated antibody secreting cells (ASC). Importantly, LN-USC showed the best effect on LN in MRL/lpr mice among the three USC types. Additionally, LN-USC markedly downregulated M1 polarization of macrophages when injected into MRL/lpr mice or co-cultured with human acute monocytic leukemia cell (THP1)-derived M0 macrophages. Moreover, the regulative effect on macrophage polarization and therapeutic efficacy on LN were reversed after knocking down C-X-C motif chemokine ligand 14 (CXCL14) of LN-USC.

SIGNIFICANCE

These results suggested that transplantation of LN-USC alleviated LN in MRL/lpr mice via inhibiting M1 polarization of macrophages in a CXCL14-dependent manner, indicating that USC serve as a prospective candidate for autologous stem cell therapy of LN.

Biomaterial-enhanced delivery of stem cell-derived exosomes for skin inflammatory diseases: Mechanisms and therapeutic advances

Inflammatory skin diseases such as psoriasis, atopic dermatitis, vitiligo, and lupus erythematosus present persistent therapeutic challenges due to their chronic nature, immune dysregulation, and suboptimal treatment outcomes. Stem cell-derived exosomes have emerged as a promising cell-free therapeutic approach, capable of modulating immune responses, promoting tissue regeneration, and restoring skin homeostasis. This review provides a comprehensive overview of exosomes derived from various stem cell sources-including adipose tissue, bone marrow, umbilical cord, dental pulp, and induced pluripotent stem cells-and their roles in regulating immune cell function and facilitating skin repair. Particular emphasis is placed on biomaterial-assisted delivery strategies, such as hydrogels, nanoparticles, and engineered scaffolds, which enhance the stability, targeting, and retention of exosomes at inflammatory sites. Key immunomodulatory mechanisms, including Treg/Th17 balance, macrophage polarization, and dendritic cell regulation, are also discussed. Finally, we highlight emerging preclinical and clinical evidence supporting the integration of exosome therapy with bioactive materials as a next-generation strategy for treating inflammatory skin disorders with improved precision and durability.

M2-ApoBDs as a therapeutic strategy for systemic lupus erythematosus: targeted macrophage reprogramming and treg differentiation

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that affects various organs and systems, significantly impacting patients' health and quality of life. Conventional drugs, including glucocorticoids and standard immunosuppressive drugs, may not be enough to achieve a satisfactory therapeutic outcome in some refractory SLE patients. The abnormal phenotype and function of macrophages participate in the development of SLE. The targeted delivery to reprogram macrophage in SLE has been a long-standing challenge. Apoptotic bodies (ApoBDs) are essential for intercellular communications. This study aims to explore an effective and targeted treatment to SLE via macrophage reprogramming and Treg differentiation. In this work, we found that M2 macrophages-derived ApoBDs (M2-ApoBDs) could selectively target and localize to the spleen, where they were engulfed by splenic macrophages (phagocytic rate 73.4%). Single-cell RNA sequencing revealed that the efferocytosis of M2-ApoBDs triggered transcriptional changes in M2 (anti-inflammatory) macrophages within the spleen, subsequently promoting the differentiation of Treg cells in vivo. Immunological experiments revealed that M2-ApoBDs prompted the reprogramming of M2 macrophages in vitro, which subsequently influenced Treg cell differentiation via ligand-receptor interactions. In SLE mice, M2-ApoBDs alleviated the disease progression, including 24-hours urinary protein, plasma creatinine, plasma C3 levels, and glomerular sclerosis and interstitial fibrosis. These findings show that M2-ApoBDs can targeted-modulate macrophage polarization and Treg immune regulation, offering a novel therapeutic strategy for the effective treatment of SLE.

Unraveling the interplay between mesenchymal stem cells, gut microbiota, and systemic sclerosis: therapeutic implications

Systemic sclerosis (SSc) is an autoimmune disease with progressive fibrotic disorders in multiple organs. Mesenchymal stem cells (MSCs) have shown great potential in treating SSc, but the exact regulatory mechanism is not fully understood. In this study, we used human umbilical cord-derived MSCs (hUC-MSCs) to treat SSc mice induced by bleomycin. The gut microbiota composition and predicted functions were analyzed using 2bRAD sequencing of fecal samples from control, SSc, and MSCs-treated mice. Treatment with MSCs improved the bleomycin-induced SSc mice, characterized by significantly reduced collagen deposition and dermal thickness. The gut microbiota of SSc mice exhibited lower species evenness and was clearly separated from the control mice based on beta diversity. MSC treatment led to a significant reduction of conditionally pathogenic bacteria enriched in SSc, including Akkermansia muciniphila and Parasutterella excrementihominis. Conversely, the relative abundance of butyrate-producing bacteria, such as Roseburia, Butyricicoccus porcorum, and Gemmiger formicilis, was notably increased in MSCs-treated SSc mice. Additionally, the functional analysis revealed that MSCs intervention effectively enhanced sulfur metabolism, tryptophan metabolism, citrate cycle, RNA polymerase, and beta-lactam resistance. In summary, the findings in the present study have suggested the close association between gut microbiota and metabolic dysbiosis in mice with SSc. The administration of MSCs has been shown to regulate the disrupted metabolic pathways in SSc mice, thus restoring the normal function of the gut microbiota. This study provides valuable insights into the specific gut microbiota and metabolic pathways involved in the efficacy of MSC treatment, thereby proposing a novel therapeutic strategy for SSc.

IMPORTANCE

Human umbilical cord-derived mesenchymal stem cells (HUC‑MSCs) demonstrate efficacy in alleviating skin thickening and collagen deposition in systemic sclerosis (SSc) mice, which also regulate the gut microbiota composition and function. Specifically, MSC intervention leads to a notable increase in butyrate-producing bacteria, a decrease in Akkermansia muciniphila and Parasutterella excrementihominis, and a reversal of the dysregulated microbial function in SSc mice. These findings underscore the potential significance of gut microbiota in the therapeutic effects of MSCs in SSc.

Immunoregulatory iPSC-derived non-lymphoid progeny in autoimmunity and GVHD alloimmunity

Non-lymphoid immunoregulatory cells, including mesenchymal stem cells (MSCs), myeloid-derived suppressor cells (MDSCs), regulatory macrophages (Mregs), and tolerogenic dendritic cells (Tol-DCs), play critical roles in maintaining immune homeostasis. However, their therapeutic application in autoimmune diseases and graft-versus-host disease (GVHD) has received comparatively less attention. Induced pluripotent stem cells (iPSCs) offer a promising platform for cell engineering, enabling superior quality control, scalable production, and large-scale in vitro expansion of iPSC-derived non-lymphoid immunoregulatory cells. These advances pave the way for their broader application in autoimmune disease and GVHD therapy. Recent innovations in iPSC differentiation protocols have facilitated the generation of these cell types with functional characteristics akin to their primary counterparts. This review explores the unique features and generation processes of iPSC-derived non-lymphoid immunoregulatory cells, their therapeutic potential in GVHD and autoimmune disease, and their progress toward clinical translation. It emphasizes the phenotypic and functional diversity within each cell type and their distinct effects on disease modulation. Despite these advancements, challenges persist in optimizing differentiation efficiency, ensuring functional stability, and bridging the gap to clinical application. By synthesizing current methodologies, preclinical findings, and translational efforts, this review underscores the transformative potential of iPSC-derived non-lymphoid immunoregulatory cells in advancing cell-based therapies for alloimmune and autoimmune diseases.

The role of monocytes and macrophages in idiopathic inflammatory myopathies: insights into pathogenesis and potential targets

Idiopathic inflammatory myopathies (IIMs) are heterogeneous autoimmune disorders characterized by muscle inflammation, weakness, and extramuscular manifestations such as interstitial lung disease, skin rash, arthritis, dysphagia, myocarditis and other systemic organ involvement. Although T and B cells have historically been central to the understanding of IIM immunopathology, monocytes and their differentiated progenitor cells, macrophages, are increasingly being recognized as critical mediators of both tissue damage and repair. In subtypes such as dermatomyositis, immune-mediated necrotizing myopathy and antisynthetase syndrome, macrophages infiltrate skeletal muscle and other affected tissues, contributing to inflammation via production of pro-inflammatory cytokines, chemokines, and reactive oxygen species. Dysregulated interferon signaling, mitochondrial stress, and aberrant metabolic states in these cells further perpetuate tissue injury in IIMs. Conversely, certain macrophage subsets can support muscle fiber regeneration and dampen inflammation, underscoring the dual roles these cells can play. Future research into the heterogeneity of monocytes and macrophages, including single-cell transcriptomic and metabolomic approaches, will help clarify disease mechanisms, identify biomarkers of disease activity and prognosis, and guide novel therapeutic strategies targeting these innate immune cells in IIM.

Significant correlations of upregulated MPO expression with cytokine imbalance in ankylosing spondylitis patients and the inhibitory effect mediated by mesenchymal stem cells

BACKGROUND

Little is known regarding both the role of myeloperoxidase (MPO) and the impact of mesenchymal stem cells (MSCs) on inflammatory and immune responses in ankylosing spondylitis (AS). This study is aimed to explore the role of MPO and the regulatory effect of umbilical cord-derived MSCs on MPO expression in monocytes in AS.

METHODS

MPO mRNA expression in the peripheral blood mononuclear cells (PBMCs) was detected by Real-time PCR. Cytokines including IL-2, IFN-γ, IL-17 A, IL-4, IL-10, IL-6 and TNF-α were determined by flow cytometry. A co-culture system was established by culturing THP-1 cells with MSCs at a ratio of 5:1.

RESULTS

Increased mRNA expression of MPO was observed in PBMCs of AS patients compared to healthy controls (P < 0.05). The mRNA expression of MPO was positively associated with C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) (P < 0.05) in AS. Besides, the levels of IL-2, IL-10, IFN-γ, IL-17 A, IL-4, IL-6, TNF-α in plasma were notably increased in AS (P < 0.05). Positive correlations between MPO expression and IL-2, IFN -γ, IL-4, TNF-α as well as IL-6 were demonstrated in AS (P < 0.05). Furthermore, MSCs remarkably suppressed the mRNA expression of MPO along with the secretion of IL-17 A and TNF-α, but promoted IL-10 generation in monocytes.

CONCLUSION

MPO expression is significantly upregulated and correlates with cytokine imbalance in AS. It may serve as a valuable immunotherapeutic target for AS. MSCs can significantly inhibit monocyte-mediated inflammatory response potentially by downregulating MPO in monocytes.

Autophagy activation within inflammatory microenvironment improved the therapeutic effect of MSC-Derived extracellular Vesicle in SLE

INTRODUCTION

Developing strategies to improve the therapeutic efficacy of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in autoimmune diseases have garnered increased attention.

OBJECTIVES

To evaluate whether rapamycin-induced autophagy within the systemic lupus erythematosus (SLE) inflammatory microenvironment (Rapa-SLE) augments the therapeutic effects of MSC-derived EVs in SLE.

METHODS

The therapeutic potential of the resulting EVs (Rapa-SLE-EV) was assessed in MRL/lpr mice. Rapa-SLE-EVs were compared with EVs derived from MSCs from MSCs cultured with EV-depleted fetal bovine serum (FBS-EV), EVs from MSCs cultured with rapamycin-treated FBS (Rapa-FBS-EV), and EVs exposed to SLE serum without rapamycin (SLE-EV). The autoimmune response, renal function, and pathological damage were assessed among the mouse groups. Additionally, mechanistic investigations into the role of the anti-inflammatory protein IDO1 within the EVs.

RESULTS

Interaction with the SLE inflammatory microenvironment triggered autophagy in MSCs, which was further enhanced by rapamycin treatment. Rapa-SLE-EV administration significantly ameliorated the autoimmune response and renal damage in MRL/lpr mice, outperforming other MSC-EV groups. This treatment mitigated key manifestations of SLE, including reduced autoantibody levels, as well as splenomegaly, and lymphadenopathy. Furthermore, Rapa-SLE-EV demonstrated superior suppression of plasma inflammatory cytokines, preserved renal function, mitigated pathological damage, and reduced glomerular immune complex deposition. Mechanistically, Rapa-SLE-EV exhibits exceptional inhibitory effects on SLE-B cell function, benefited by the high expression of the anti-inflammatory protein IDO1, which was confirmed to enter SLE-B cells through EVs.

CONCLUSIONS

We developed a novel strategy to improve the therapeutic efficacy of MSC-EVs in SLE and confirmed that the immunomodulatory function of the MSC-EVs is enhanced through autophagic activation and interaction with the SLE serum microenvironment, a process likely benefited by the high expression of IDO1.

The Role of Exosomes in Medical Dermatology: Literature Review and Update

BACKGROUND

Exosomes are extracellular vesicles, composed of a phospholipid bilayer, that are primarily derived from stem cells. The contents of exosomes can be incorporated into the tissue in which they are introduced, which presents a unique therapeutic option.

AIMS

Exosomes have been investigated as a treatment for a number of medical ailments, but the literature supporting these indications is inconclusive. In addition, much of the study on exosomes and their uses has been recently completed. Thus, this review summarizes the efficacy and implications of exosomes in the treatment of different dermatologic conditions.

METHODS

A literature review surrounding the use of exosomes for multiple medical dermatological conditions was conducted. Additionally, we present numerous practical cases in which patients had been treated with exosomes.

RESULTS

Overall, the success of exosomes in treating medical dermatologic conditions demonstrated varying efficacy in the literature, but the preliminary evidence is generally positive. The patient cases also showed satisfactory clinical outcomes but further studies and cases will be necessary to fully characterize the efficacy of exosomes and the ideal modalities for their application, including formulation, mode of distribution, and frequency of treatment.

CONCLUSIONS

Exosomes may serve as an effective treatment option for wound healing, reconstruction of skin flaps, radiation dermatitis, acne vulgaris, psoriasis, atopic dermatitis, allergic contact dermatitis, lichen simplex chronicus, vulvar lichen sclerosis, systemic sclerosis, systemic lupus erythematosus, and vitiligo although additional studies are needed to confirm their efficacy and safety.

Mechanism and application of mesenchymal stem cells and their secreting extracellular vesicles in regulating CD4+T cells in immune diseases

Mesenchymal stem cells (MSCs) show significant promise in treating immune diseases due to their ability to differentiate into various cell types and their immunomodulatory properties. However, the mechanisms by which MSCs regulate CD4+T cells, essential for immune responses, are not yet fully understood. This study aims to provide a comprehensive overview of how MSCs and their secreted extracellular vesicles (EVs) modulate CD4+T cells in immune diseases. We begin by discussing the immunomodulatory properties of MSCs and the factors contributing to their effectiveness. Following this, we explore how MSCs interact with CD4+T cells through various pathways, including the secretion of soluble factors, direct cell-cell contact, and EV-mediated communication. A key focus is on the therapeutic potential of MSC-derived EVs, which are rich in bioactive molecules such as proteins, lipids, and nucleic acids. These molecules can regulate the phenotype and function of CD4+T cells. The challenges and future perspectives in utilizing MSCs and EVs for immune-disease therapy are also addressed. Overall, this research aims to enhance our understanding of the mechanisms behind MSC-mediated regulation of CD4+T cells and provide insights into the potential use of MSCs and EVs as therapeutic tools in immune diseases. In summary, understanding how MSCs and their EVs control CD4+T cells can offer valuable perspectives for developing innovative immunotherapeutic approaches. Leveraging the immunomodulatory capacity of MSCs and EVs holds promise for managing immune-related disorders.

Therapeutic Efficacy and Promise of Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles in Aging and Age-Related Disorders

The global issue of aging populations has become increasingly prominent, thus the research and development for anti-aging therapies to assure longevity as well as to ameliorate age-related complications is put high on the agenda. The young humoral milieu has been substantiated to impart youthful characteristics to aged cells or organs. Extracellular vesicles (EVs) are a heterogeneous group of cell-derived membrane-limited structures that serve as couriers of proteins and genetic material to regulate intercellular communication. Of note, EVs appeared to be an indispensable component of young blood in prolonging lifespans, and circulating EVs have been indicated to mediate the beneficial effect of a young milieu on aging. Human umbilical cord mesenchymal stem cell-derived EVs (HUCMSC-EVs), isolated from the youngest adult stem cell source, are speculated to reproduce the function of circulating EVs in young blood and partially revitalize numerous organs in old animals. Robust evidence has suggested HUCMSC-EVs as muti-target therapeutic agents in combating aging and alleviating age-related degenerative disorders. Here, we provide a comprehensive overview of the anti-aging effects of HUCMSC-EVs in brain, heart, vasculature, kidney, muscle, bone, and other organs. Furthermore, we critically discuss the current investigation on engineering strategies of HUCMSC-EVs, intending to unveil their full potential in the field of anti-aging research.

Macrophage involvement in idiopathic inflammatory myopathy: pathogenic mechanisms and therapeutic prospects

Idiopathic inflammatory myopathies are a group of systemic autoimmune diseases characterized by chronic muscle inflammation and diverse clinical manifestations. Macrophages, pivotal components of innate immunity, are implicated in immune responses, inflammation resolution, and tissue repair. Distinct macrophage polarization states play vital roles in disease progression and resolution. Mechanistically, activated macrophages release proinflammatory cytokines, chemokines, and reactive oxygen species, perpetuating immune responses and tissue damage. Dysregulated macrophage polarization contributes to sustained inflammation. Here, we reviewed the intricate contributions of macrophages to IIM pathogenesis and explored novel therapeutic avenues. We discussed emerging strategies targeting macrophages, including receptor-based interventions and macrophage polarization modulation, for IIM treatment. This review underscores the multifaceted involvement of macrophages in IIM pathogenesis and offers insights into potential therapeutic approaches targeting these immune cells for disease management.

Roles of macrophages in lupus nephritis

LN is a serious complication of systemic lupus erythematosus (SLE), affecting up to 60% of patients with SLE and may lead to end-stage renal disease (ESRD). Macrophages play multifaceted roles in the pathogenesis of LN, including clearance of immune complexes, antigen presentation, regulation of inflammation, and tissue repair. Macrophages are abundant in the glomeruli and tubulointerstitium of LN patients and are positively correlated with serum creatinine levels and the severity of renal pathology. It has been shown that the infiltration of macrophages is closely associated with several clinical indicators, such as serum creatinine and complement C3 levels, anti-dsDNA antibody titers, Austin score, interstitial fibrosis and renal tubular atrophy. Moreover, cytokines expressed by macrophages were upregulated at LN onset and downregulated after remission, suggesting that macrophages may serve as markers of LN pathogenesis and remission. Therapies targeting macrophages have been shown to alleviate LN. There are two main types of macrophages in the kidney: kidney-resident macrophages (KRMs) and monocyte-derived macrophages (MDMs). KRMs and MDMs play different pathological roles in LN, with KRMs promoting leukocyte recruitment at sites of inflammation by expressing monocyte chemokines, while MDMs may exacerbate autoimmune responses by presenting immune complex antigens. Macrophages exhibit high plasticity and can differentiate into various phenotypes in response to distinct environmental stimuli. M1 (proinflammatory) macrophages are linked to the progression of active SLE, whereas the M2 (anti-inflammatory) phenotype is observed during the remission phase of LN. The polarization of macrophages in LN can be manipulated through multiple pathways, such as the modulation of signaling cascades including TLR 2/1, S1P, ERS, metabolic reprogramming, and HMGB1. This paper provides a comprehensive overview of the role of macrophages in the progression of lupus nephritis (LN), and elucidates how these cells and their secretory products function as indicators and therapeutic targets for the disease in the context of diagnosis and treatment of LN.

Influence of mesenchymal stem cells from different origins on the therapeutic effectiveness of systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune inflammatory disorder characterized by alterations in the balance between inflammatory and regulatory cytokines. Mesenchymal stem cells (MSCs), which are non-hematopoietic stem cells with multipotent differentiation potential, due to their immunomodulatory, tissue repair, low immunogenicity, and chemotactic properties, have garnered increasing interest in SLE treatment. Studies increasingly reveal the heterogeneous nature of MSC populations. With sources including dental pulp, adipose tissue, bone marrow, and umbilical cord, the therapeutic effects of MSCs on SLE vary depending on their origin. This review consolidates clinical research on MSCs from different sources in treating SLE and analyzes the possible causes underlying these variable outcomes. Additionally, it elucidates five potential factors impacting the outcomes of MSC therapy in SLE: the influence of the microenvironment on MSCs, the complexity and paradoxical aspects of MSC mechanisms in SLE treatment, the heterogeneity of MSCs, the in vivo differentiation potential and post-transplant survival rates of MSCs, and disparities in MSC preparation conditions.

Emerging Role and Mechanism of Mesenchymal Stem Cells-Derived Extracellular Vesicles in Rheumatic Disease

Mesenchymal stem cells (MSCs) are pluripotent stem cells derived from mesoderm. Through cell-to-cell contact or paracrine effects, they carry out biological tasks like immunomodulatory, anti-inflammatory, regeneration, and repair. Extracellular vesicles (EVs) are the primary mechanism for the paracrine regulation of MSCs. They deliver proteins, nucleic acids, lipids, and other active compounds to various tissues and organs, thus facilitating intercellular communication. Rheumatic diseases may be treated using MSCs and MSC-derived EVs (MSC-EVs) due to their immunomodulatory capabilities, according to mounting data. Since MSC-EVs have low immunogenicity, high stability, and similar biological effects as to MSCs themselves, they are advantageous over cell therapy for potential therapeutic applications in rheumatoid arthritis, systemic erythematosus lupus, systemic sclerosis, Sjogren's syndrome, and other rheumatoid diseases. This review integrates recent advances in the characteristics, functions, and potential molecular mechanisms of MSC-EVs in rheumatic diseases and provides a new understanding of the pathogenesis of rheumatic diseases and MSC-EV-based treatment strategies.

Current cell therapies for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease in which multiple organs are damaged by the immune system. Although standard treatment options such as hydroxychloroquine (HCQ), glucocorticoids (GCs), and other immunosuppressive or immune-modulating agents can help to manage symptoms, they do not offer a cure. Hence, there is an urgent need for the development of novel drugs and therapies. In recent decades, cell therapies have been used for the treatment of SLE with encouraging results. Hematopoietic stem cell transplantation, mesenchymal stem cells, regulatory T (Treg) cell, natural killer cells, and chimeric antigen receptor T (CAR T) cells are advanced cell therapies which have been developed and evaluated in clinical trials in humans. In clinical application, each of these approaches has shown advantages and disadvantages. In addition, further studies are necessary to conclusively establish the safety and efficacy of these therapies. This review provides a summary of recent clinical trials investigating cell therapies for SLE treatment, along with a discussion on the potential of other cell-based therapies. The factors influencing the selection of common cell therapies for individual patients are also highlighted.

Therapeutic Potential and Mechanisms of Mesenchymal Stem Cell and Mesenchymal Stem Cell-Derived Extracellular Vesicles in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic and inflammatory skin disease with intense itchiness that is highly prevalent worldwide.The pathogenesis of AD is complex and closely related to genetic factors, immunopathogenic factors, environmental factors, and skin infections. Mesenchymal stem cells (MSCs) are non-hematopoietic progenitor cells derived from the mesenchymal stroma. They have anti-inflammatory, anti-apoptotic, and regenerative properties. Numerous studies demonstrate that MSCs can play a therapeutic role in AD by regulating various immune cells, maintaining immune homeostasis, and promoting the repair of damaged tissues. The key mediators for their biological functions are extracellular vesicles (MSC-Evs) and soluble cytokines derived from MSCs. The safety and efficacy of MSCs have been demonstrated in clinical Phase I / IIa trials for AD. This paper provides a comprehensive review of the pathogenesis of AD and the currently published studies on the function of MSCs and MSC-Evs in AD, primarily including the pathogenesis and the immunomodulatory impacts of MSCs and MSC-Evs, along with advancements in clinical studies. It provides insights for comprehending AD pathogenesis and investigating treatments based on MSCs.

Biopotency and surrogate assays to validate the immunomodulatory potency of extracellular vesicles derived from mesenchymal stem/stromal cells for the treatment of experimental autoimmune uveitis

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have been recognized as promising cytotherapeutics due to their demonstrated immunomodulatory effects in various preclinical models. The immunomodulatory capabilities of EVs stem from the proteins and genetic materials they carry from parent cells, but the cargo contents of EVs are significantly influenced by MSC tissues and donors, cellular age and culture conditions, resulting in functional variations. However, there are no surrogate assays available to validate the immunomodulatory potency of MSC-EVs before in vivo administration. In previous work, we discovered that microcarrier culture conditions enhance the immunomodulatory function of MSC-EVs, as well as the levels of immunosuppressive molecules such as TGF-β1 and let-7b in MSC-EVs. Building on these findings, we investigated whether TGF-β1 levels in MSC-EVs could serve as a surrogate biomarker for predicting their potency in vivo. Our studies revealed a strong correlation between TGF-β1 and let-7b levels in MSC-EVs, as well as their capacity to suppress IFN-γ secretion in stimulated splenocytes, establishing biopotency and surrogate assays for MSC-EVs. Subsequently, we validated MSC-EVs generated from monolayer cultures (ML-EVs) or microcarrier cultures (MC-EVs) using murine models of experimental autoimmune uveoretinitis (EAU) and additional in vitro assays reflecting the Mode of Action of MSC-EVs in vivo. Our findings demonstrated that MC-EVs carrying high levels of TGF-β1 exhibited greater efficacy than ML-EVs in halting disease progression in mice with EAU as well as inducing apoptosis and inhibiting the chemotaxis of retina-reactive T cells. Additionally, MSC-EVs suppressed the MAPK/ERK pathway in activated T cells, with treatment using TGF-β1 or let-7b showing similar effects on the MAPK/ERK pathway. Collectively, our data suggest that MSC-EVs directly inhibit the infiltration of retina-reactive T cells toward the eyes, thereby halting the disease progression in EAU mice, and their immunomodulatory potency in vivo can be predicted by their TGF-β1 levels.

Exosomes derived from cord blood Treg cells promote diabetic wound healing by targeting monocytes

Chronic nonhealing diabetic wounds are a critical clinical challenge. Regulatory T cells (Tregs) are immunosuppressive modulators affecting wound healing progression by controlling the inflammatory response. The current study attempted to investigate whether the exosomes derived from cord blood (CB) Tregs can accelerate the healing process. Exosomes were isolated from CB-Treg cultures using ultracentrifugation and validated with different specific markers of exosomes. The purified CB-Treg-derived exosomes were co-cultured with peripheral blood mononuclear cells (PBMCs) and CD14+ monocytes. The migration-promoting effect of CB-Treg-derived exosomes on fibroblasts and endothelial cells was investigated. We used thermosensitive Pluronic F-127 hydrogel (PF-127) loaded with CB-Treg-derived exosomes in a diabetic wound healing mouse model. CB-Treg-derived exosomes with 30-120 nm diameters revealed exosome-specific markers, such as TSG101, Alix, and CD63. CB-Treg-derived exosomes were mainly bound to the monocytes when co-cultured with PBMCs, and promoted monocyte polarization to the anti-inflammatory phenotype (M2) in vitro. CB-Treg-derived exosomes enhanced the migration of endothelial cells and fibroblasts. Furthermore, CB-Treg-derived exosomes treatment accelerated wound healing by downregulating inflammatory factor levels and upregulating the M2 macrophage ratio in vivo. Our findings indicated that CB-Treg-derived exosomes could be a promising cell-free therapeutic strategy for diabetic wound healing, partly by targeting monocytes.

Therapeutic role of extracellular vesicles from human umbilical cord mesenchymal stem cells and their wide therapeutic implications in inflammatory bowel disease and other inflammatory disorder

The chronic immune-mediated inflammatory condition known as inflammatory bowel disease (IBD) significantly affects the gastrointestinal system. While the precise etiology of IBD remains elusive, extensive research suggests that a range of pathophysiological pathways and immunopathological mechanisms may significantly contribute as potential factors. Mesenchymal stem cells (MSCs) have shown significant potential in the development of novel therapeutic approaches for various medical conditions. However, some MSCs have been found to exhibit tumorigenic characteristics, which limit their potential for medical treatments. The extracellular vesicles (EVs), paracrine factors play a crucial role in the therapeutic benefits conferred by MSCs. The EVs consist of proteins, microRNAs, and lipids, and are instrumental in facilitating intercellular communication. Due to the ease of maintenance, and decreased immunogenicity, tumorigenicity the EVs have become a new and exciting option for whole cell treatment. This review comprehensively assesses recent preclinical research on human umbilical cord mesenchymal stem cell (hUC-MSC)-derived EVs as a potential IBD therapy. It comprehensively addresses key aspects of various conditions, including diabetes, cancer, dermal injuries, neurological disorders, cardiovascular issues, liver and kidney diseases, and bone-related afflictions.

Mesenchymal stem cells-derived extracellular vesicles ameliorate lupus nephritis by regulating T and B cell responses

BACKGROUND

Human umbilical cord mesenchymal stem cells-derived extracellular vesicles (hUCMSC-EVs) have potent immunomodulatory properties similar to parent cells. This study investigated the therapeutic effects and immunomodulatory mechanisms of hUCMSC-EVs in an experimental lupus nephritis model.

METHODS

The hUCMSC-EVs were isolated by using differential ultracentrifugation. In vivo, the therapeutic effects of hUCMSC-EVs in lupus-prone MRL/lpr mice were investigated, and the mechanisms of treatment were explored according to the abnormal T and B cell responses among both the spleen and kidney.

RESULTS

MRL/lpr mice treated with hUCMSC-EVs reduced proteinuria extent, serum creatinine and renal pathological damage; decreased splenic index and serum anti-dsDNA IgG level; and improved survival rate. hUCMSC-EVs lowered the percentage of T helper (Th)1 cells, double-negative T (DNT) cells, and plasma cells among splenocytes; inhibited the infiltration of Th17 cells but promoted regulatory T (Treg) cells in the kidney, followed by a reduction in pro-inflammatory cytokine levels(IFN-γ, IL-2, IL-6, IL-21, and IL-17 A). In addition, hUCMSC-EVs inhibited the activation of STAT3 and down-regulated IL-17 A protein levels in the kidney.

CONCLUSION

The results of this study demonstrated that hUCMSC-EVs had therapeutic effects on experimental lupus nephritis (LN) by regulating Th1/Th17/Treg imbalance and inhibiting DNT and plasma cells. Additionally, hUCMSC-EVs inhibited Th17 cell differentiation in kidney by regulating the IL-6/STAT3/IL-17 signal pathway, which might be an important mechanism for alleviating renal injury. Taken together, we demonstrated that hUCMSC-EVs regulating T and B cell immune responses might represent a novel mechanism of hUCMSCs in treating LN, thus providing a new strategy for treating LN.

The science of exosomes: Understanding their formation, capture, and role in cellular communication

Extracellular vesicles (EVs) serve as a crucial method for transferring information among cells, which is vital in multicellular organisms. Among these vesicles, exosomes are notable for their small size, ranging from 20 to 150 nm, and their role in cell-to-cell communication. They carry lipids, proteins, and nucleic acids between cells. The creation of exosomes begins with the inward budding of the cell membrane, which then encapsulates various macromolecules as cargo. Once filled, exosomes are released into the extracellular space and taken up by target cells via endocytosis and similar processes. The composition of exosomal cargo varies, encompassing diverse macromolecules with specific functions. Because of their significant roles, exosomes have been isolated from various cell types, including cancer cells, endothelial cells, macrophages, and mesenchymal cells, with the aim of harnessing them for therapeutic applications. Exosomes influence cellular metabolism, and regulate lipid, glucose, and glutamine pathways. Their role in pathogenesis is determined by their cargo, which can manipulate processes such as apoptosis, proliferation, inflammation, migration, and other molecular pathways in recipient cells. Non-coding RNA transcripts, a common type of cargo, play a pivotal role in regulating disease progression. Exosomes are implicated in numerous biological and pathological processes, including inflammation, cancer, cardiovascular diseases, diabetes, wound healing, and ischemic-reperfusion injury. As a result, they hold significant potential in the treatment of both cancerous and non-cancerous conditions.

Proteomic characterization of hUC-MSC extracellular vesicles and evaluation of its therapeutic potential to treat Alzheimer's disease

In recent years, human umbilical cord mesenchymal stem cell (hUC-MSC) extracellular vesicles (EVs) have been used as a cell replacement therapy and have been shown to effectively overcome some of the disadvantages of cell therapy. However, the specific mechanism of action of EVs is still unclear, and there is no appropriate system for characterizing the differences in the molecular active substances of EVs produced by cells in different physiological states. We used a data-independent acquisition (DIA) quantitative proteomics method to identify and quantify the protein composition of two generations EVs from three different donors and analysed the function and possible mechanism of action of the proteins in EVs of hUC-MSCs via bioinformatics. By comparative proteomic analysis, we characterized the different passages EVs. Furthermore, we found that adaptor-related protein complex 2 subunit alpha 1 (AP2A1) and adaptor-related protein complex 2 subunit beta 1 (AP2B1) in hUC-MSC-derived EVs may play a significant role in the treatment of Alzheimer's disease (AD) by regulating the synaptic vesicle cycle signalling pathway. Our work provides a direction for batch-to-batch quality control of hUC-MSC-derived EVs and their application in AD treatment.

Potential Therapeutic Application and Mechanism of Action of Stem Cell-Derived Extracellular Vesicles (EVs) in Systemic Lupus Erythematosus (SLE)

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease that affects nearly 3.41 million people globally, with 90% of the cases affecting women of childbearing age. SLE is a complex disease due to the interplay of various immunological pathways and mechanisms. This scoping review aims to highlight the latest research findings on the therapeutic mechanisms of action of EVs in SLE. Relevant research articles were identified using the PRISMA framework from databases such as PubMed/MEDLINE (National Library of Medicine), Scopus (Elsevier), and Web of Science: Core Collection (Clarivate Analytics) from July 2023 to October 2023. Eleven studies met the inclusion criteria and thus were included in this scoping review. The findings showed that EVs have therapeutic effects on ameliorating the disease progression of SLE. EVs can reduce the pro-inflammatory cytokines and increase the anti-inflammatory cytokines. Moreover, EVs can increase the levels of regulatory T cells, thus reducing inflammation. EVs also have the potential to regulate B cells to alleviate SLE and reduce its adverse effects. The scoping review has successfully analysed the therapeutic potential in ameliorating the disease progression of SLE. The review also includes prospects to improve the effects of EVs further to increase the therapeutic effects on SLE.

Mesenchymal stromal cell derived extracellular vesicles as a therapeutic tool: immune regulation, MSC priming, and applications to SLE

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a dysfunction of the immune system. Mesenchymal stromal cell (MSCs) derived extracellular vesicles (EVs) are nanometer-sized particles carrying a diverse range of bioactive molecules, such as proteins, miRNAs, and lipids. Despite the methodological disparities, recent works on MSC-EVs have highlighted their broad immunosuppressive effect, thus driving forwards the potential of MSC-EVs in the treatment of chronic diseases. Nonetheless, their mechanism of action is still unclear, and better understanding is needed for clinical application. Therefore, we describe in this review the diverse range of bioactive molecules mediating their immunomodulatory effect, the techniques and possibilities for enhancing their immune activity, and finally the potential application to SLE.

Mechanisms of Stem Cells and Their Secreted Exosomes in the Treatment of Autoimmune Diseases

Stem cells play a therapeutic role in many diseases by virtue of their strong self-renewal and differentiation abilities, especially in the treatment of autoimmune diseases. At present, the mechanism of the stem cell treatment of autoimmune diseases mainly relies on their immune regulation ability, regulating the number and function of auxiliary cells, anti-inflammatory factors and proinflammatory factors in patients to reduce inflammation. On the other hand, the stem cell- derived secretory body has weak immunogenicity and low molecular weight, can target the site of injury, and can extend the length of its active time in the patient after combining it with the composite material. Therefore, the role of secretory bodies in the stem cell treatment of autoimmune diseases is increasingly important.

Advances in mesenchymal stem cell-derived extracellular vesicles therapy for Sjogren's syndrome-related dry eye disease

Sjogren's syndrome (SS) is a chronic autoimmune disorder that affects exocrine glands, particularly lacrimal glands, leading to dry eye disease (DED). DED is a common ocular surface disease that affects millions of people worldwide, causing discomfort, visual impairment, and even blindness in severe cases. However, there is no definitive cure for DED, and existing treatments primarily relieve symptoms. Consequently, there is an urgent need for innovative therapeutic strategies based on the pathophysiology of DED. Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic tool for various autoimmune disorders, including SS-related DED (SS-DED). A particularly intriguing facet of MSCs is their ability to produce extracellular vesicles (EVs), which contain various bioactive components such as proteins, lipids, and nucleic acids. These molecules play a key role in facilitating communication between cells and modulating a wide range of biological processes. Importantly, MSC-derived EVs (MSC-EVs) have therapeutic properties similar to those of their parent cells, including immunomodulatory, anti-inflammatory, and regenerative properties. In addition, MSC-EVs offer several notable advantages over intact MSCs, including lower immunogenicity, reduced risk of tumorigenicity, and greater convenience in terms of storage and transport. In this review, we elucidate the underlying mechanisms of SS-DED and discuss the relevant mechanisms and targets of MSC-EVs in treating SS-DED. In addition, we comprehensively review the broader landscape of EV application in autoimmune and corneal diseases. This review focuses on the efficacy of MSC-EVs in treating SS-DED, a field of study that holds considerable appeal due to its multifaceted regulation of immune responses and regenerative functions.

Identify the influences of systemic lupus erythematosus on acquired ADAMTS13-deficient thrombotic thrombocytopenic purpura using comprehensive bioinformatics analysis

BACKGROUND

The association between acquired ADAMTS13-deficient thrombotic thrombocytopenic purpura (aTTP) and systemic lupus erythematosus (SLE) has been studied; however, the underlying molecular causes remain poorly understood. This research aimed to employ bioinformatics approaches to elucidate potential molecular mechanisms contributing to the pathogenesis of SLE and aTTP.

MATERIAL AND METHODS

The Gene Expression Omnibus (GEO) database yielded GSE121239 and GSE36418 to get mutual different expression genes (DEGs). Subsequently, DEGs were subjected to process Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Then, the DEGs were used for protein-protein interaction (PPI) analysis and screened for hub genes and drugs by the DGIDB drug database.

RESULTS

A total of 87 DEGs between the SLE and TTP datasets were identified. In the GO and KEGG analyses, DEGs were mainly enriched in the "regulation of transcription by RNA polymerase II" and "signaling pathways regulating pluripotency of stem cells." After a PPI analysis, three hub genes (BMPR2, SMAD5, and ATF2) were identified. Finally, two drugs targeted to ATF2 were predicted by the DGIDB drug database.

CONCLUSIONS

Three core genes were linked to the molecular pathogenesis of SLE and aTTP, and two drugs may be viable treatments for both diseases.

Advances in Mesenchymal stem cells regulating macrophage polarization and treatment of sepsis-induced liver injury

Sepsis is a syndrome of dysregulated host response caused by infection, which leads to life-threatening organ dysfunction. It is a familiar reason of death in critically ill patients. Liver injury frequently occurs in septic patients, yet the development of targeted and effective treatment strategies remains a pressing challenge. Macrophages are essential parts of immunity system. M1 macrophages drive inflammation, whereas M2 macrophages possess anti-inflammatory properties and contribute to tissue repair processes. Mesenchymal stem cells (MSCs), known for their remarkable attributes including homing capabilities, immunomodulation, anti-inflammatory effects, and tissue regeneration potential, hold promise in enhancing the prognosis of sepsis-induced liver injury by harmonizing the delicate balance of M1/M2 macrophage polarization. This review discusses the mechanisms by which MSCs regulate macrophage polarization, alongside the signaling pathways involved, providing an idea for innovative directions in the treatment of sepsis-induced liver injury.

Advances in the study of macrophage polarization in inflammatory immune skin diseases

When exposed to various microenvironmental stimuli, macrophages are highly plastic and primarily polarized into the pro-inflammatory M1-type and the anti-inflammatory M2-type, both of which perform almost entirely opposing functions. Due to this characteristic, macrophages perform different functions at different stages of immunity and inflammation. Inflammatory immune skin diseases usually show an imbalance in the M1/M2 macrophage ratio, and altering the macrophage polarization phenotype can either make the symptoms worse or better. Therefore, this review presents the mechanisms of macrophage polarization, inflammation-related signaling pathways (JAK/STAT, NF-κB, and PI3K/Akt), and the role of both in inflammatory immune skin diseases (psoriasis, AD, SLE, BD, etc.) to provide new directions for basic and clinical research of related diseases.

FKN secreted by kidney epithelial cells regulates macrophage activation in lupus nephritis via the Hippo signaling pathway

BACKGROUND

Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE), and its pathogenesis is not fully understood. Previously, we showed that fractalkine (FKN) expression was positively correlated with the severity of LN. Here, we aimed to study the role of the Hippo signaling pathway (HSP) and its interaction with FKN in LN in an attempt to provide novel strategies for LN treatment.

METHODS

In this study, lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-stimulated THP-1 cells were co-cultured with FKN up-regulated or down-regulated kidney epithelial cells Hkb20. FKN-knockout (KO-FKN) mice were used to construct LN model. Flow cytometric analysis, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), pathological staining, Western blot, and immunofluorescence (IF) staining were employed to investigate the role of FKN and its interaction with the Hippo signaling pathway (HSP) in LN.

RESULTS

Up-regulation of FKN in kidney epithelial cells was associated with increased macrophage activation. FKN overexpression in kidney epithelial cells suppressed apoptosis, inflammation levels, and M1 polarization of THP-1 cells and inhibited the HSP. Oppositely, FKN knockdown in kidney epithelial cells increased apoptosis, inflammation, and M1 polarization and activated the HSP. HSP inhibitor reversed the effect of FKN knockdown on THP-1 cells. In LN mice, FKN knockout and YAP inhibitor decreased the levels of renal function markers, alleviated kidney injury induced by LN, and inhibited macrophage activation in LN mice.

CONCLUSIONS

FKN down-regulation reduced the activation of macrophages in renal tissue and alleviated kidney damage by activating HSP. The regulatory effect of FKN on HSP should be confirmed in patients with LN, and the mechanism of FKN in LN should be further explored.

Therapeutic role of exosomes and conditioned medium in keloid and hypertrophic scar and possible mechanisms

Exosomes, ranging from 40 to 160 nm in diameter, are extracellular lipid bilayer microvesicles that regulate the body's physiological and pathological processes and are secreted by cells that contain proteins, nucleic acids, amino acids and other metabolites. Previous studies suggested that mesenchymal stem cell (MSC)-derived exosomes could either suppress or support keloid and hypertrophic scar progression. Although previous research has identified the potential value of MSC-exosomes in keloid and hypertrophic scar, a comprehensive analysis of different sources of MSC-exosome in keloid and hypertrophic scar is still lacking. This review mainly discusses different insights regarding the roles of MSC-exosomes in keloid and hypertrophic scar treatment and summarizes possible underlying mechanisms.

Bone Marrow: The Central Immune System

Bone marrow is known as the site of hematopoiesis. What is not being described in textbooks of immunology is the fact that bone marrow is not only a generative, but also an antigen-responsive, immune organ. It is also a major storage site for antigen-specific memory B and T cells. That bone marrow is a priming site for T cell responses to blood borne antigens was discovered exactly 20 years ago. This review celebrates this important discovery. The review provides a number of examples of medical relevance of bone marrow as a central immune system, including cancer, microbial infections, autoimmune reactions, and bone marrow transplantation. Bone marrow mesenchymal stem cell-derived stromal cells provide distinct bone marrow niches for stem cells and immune cells. By transmitting anti-inflammatory dampening effects, facilitating wound healing and tissue regeneration mesenchymal stem cells contribute to homeostasis of bone and other tissues. Based on the evidence presented, the review proposes that bone marrow is a multifunctional and protective immune system. In an analogy to the central nervous system, it is suggested that bone marrow be designated as the central immune system.

Mesenchymal Stem/Stromal Cell-Based Therapies in Systemic Rheumatic Disease: From Challenges to New Approaches for Overcoming Restrictions

Systemic rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, are chronic autoimmune diseases affecting multiple organs and tissues. Despite recent advances in treatment, patients still experience significant morbidity and disability. Mesenchymal stem/stromal cell (MSC)-based therapy is promising for treating systemic rheumatic diseases due to the regenerative and immunomodulatory properties of MSCs. However, several challenges need to be overcome to use MSCs in clinical practice effectively. These challenges include MSC sourcing, characterization, standardization, safety, and efficacy issues. In this review, we provide an overview of the current state of MSC-based therapies in systemic rheumatic diseases, highlighting the challenges and limitations associated with their use. We also discuss emerging strategies and novel approaches that can help overcome the limitations. Finally, we provide insights into the future directions of MSC-based therapies for systemic rheumatic diseases and their potential clinical applications.

Current understanding of plant-derived exosome-like nanoparticles in regulating the inflammatory response and immune system microenvironment

Natural compounds are widely used to prevent and treat various diseases due to their antioxidant and anti-inflammatory effects. As a kind of promising natural compound, plant-derived exosome-like nanoparticles (PELNs) are extracted from multivesicular bodies of various edible plants, including vegetables, foods, and fruits, and mainly regulate the cellular immune response to pathogen attacks. Moreover, PELNs could remarkably interfere with the dynamic imbalance between pro-inflammatory and anti-inflammatory effects, facilitating to maintain the homeostasis of cellular immune microenvironment. PELNs may serve as a better alternative to animal-derived exosomes (ADEs) owing to their widespread sources, cost-effectiveness, and easy accessibility. PELNs can mediate interspecies communication by transferring various cargoes such as proteins, lipids, and nucleic acids from plant cells to mammalian cells. This review summarizes the biogenesis, composition, and classification of exosomes; the common separation, purification, and characterization methods of PELNs, the potential advantages of PELNs over ADEs; and the anti-inflammatory and immunomodulatory functions of PELNs in various diseases including colitis, cancer, and inflammation-associated metabolic diseases. Additionally, the future perspectives of PELNs and the challenges associated with their clinical application are discussed.

Exosomes as biomarkers and therapeutic delivery for autoimmune diseases: Opportunities and challenges

Exosomes are spherical lipid bilayer vesicles composed of lipids, proteins and nucleic acids that deliver signaling molecules through a vesicular transport system to regulate the function and morphology of target cells, thereby involving in a variety of biological processes, such as cell apoptosis or proliferation, and cytokine production. In the past decades, there are emerging evidence that exosomes play pivotal roles in the pathological mechanisms of several autoimmune diseases (ADs), including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), type 1 diabetes mellitus (T1DM), Sjogren's syndrome (SS), multiple sclerosis (MS), inflammatory bowel disease (IBD). systemic sclerosis (SSc), etc. Several publications have shown that exosomes are involved in the pathogenesis of ADs mainly through intercellular communication and by influencing the response of immune cells. The level of exosomes and the expression of nucleic acids can reflect the degree of disease progression and are excellent biomarkers for ADs. In addition, exosomes have the potential to be used as drug carriers thanks to their biocompatibility and stability. In this review, we briefly summarized the current researches regarding the biological functions of exosomes in ADs, and provided an insight into the potential of exosomes as biomarkers and therapeutic delivery for these diseases.

Macrophage: Key player in the pathogenesis of autoimmune diseases

The macrophage is an essential part of the innate immune system and also serves as the bridge between innate immunity and adaptive immune response. As the initiator and executor of the adaptive immune response, macrophage plays an important role in various physiological processes such as immune tolerance, fibrosis, inflammatory response, angiogenesis and phagocytosis of apoptotic cells. Consequently, macrophage dysfunction is a vital cause of the occurrence and development of autoimmune diseases. In this review, we mainly discuss the functions of macrophages in autoimmune diseases, especially in systemic lupus erythematosus (SLE), rheumatic arthritis (RA), systemic sclerosis (SSc) and type 1 diabetes (T1D), providing references for the treatment and prevention of autoimmune diseases.

Intraperitoneally Delivered Umbilical Cord Lining Mesenchymal Stromal Cells Improve Survival and Kidney Function in Murine Lupus via Myeloid Pathway Targeting

To determine the therapeutic efficacy of human umbilical cord lining mesenchymal stromal cells (CL-MSCs) (US Patent number 9,737,568) in lupus-prone MRL/lpr (Faslpr) mice and elucidate its working mechanisms. A total of 4 doses of (20-25) × 106 cells/kg of CL-MSCs was given to 16-week-old female Faslpr mice by intraperitoneal injection. Three subsequent doses were given on 17 weeks, 18 weeks, and 22 weeks, respectively. Six-week-old Faslpr mice were used as disease pre-onset controls. Mice were monitored for 10 weeks. Mouse kidney function was evaluated by examining complement component 3 (C3) deposition, urinary albumin-to-creatinine ratio (ACR), and lupus nephritis (LN) activity and chronicity. Working mechanisms were elucidated by flow cytometry, Luminex/ELISA (detection of anti-dsDNA and isotype antibodies), and RNA sequencing. CL-MSCs improved mice survival and kidney function by reducing LN activity and chronicity and lymphocyte infiltration over 10 weeks. CL-MSCs also reduced urinary ACR, renal complement C3 deposition, anti-dsDNA, and isotype antibodies that include IgA, IgG1, IgG2a, IgG2b, and IgM. Immune and cytokine profiling demonstrated that CL-MSCs dampened inflammation by suppressing splenic neutrophils and monocytes/macrophages, reducing plasma IL-6, IL-12, and CXCL1 and stabilizing plasma interferon-γ and TNF-α. RNA sequencing further showed that CL-MSCs mediated immunomodulation via concerted action of pro-proinflammatory cytokine-induced chemokines and production of nitric oxide in macrophages. CL-MSCs may provide a novel myeloid (neutrophils and monocytes/macrophages)-targeting therapy for SLE.

Extracellular Vesicles in Inner Ear Therapies-Pathophysiological, Manufacturing, and Clinical Considerations

(1) Background: Sensorineural hearing loss is a common and debilitating condition. To date, comprehensive pharmacologic interventions are not available. The complex and diverse molecular pathology that underlies hearing loss may limit our ability to intervene with small molecules. The current review foccusses on the potential for the use of extracellular vesicles in neurotology. (2) Methods: Narrative literature review. (3) Results: Extracellular vesicles provide an opportunity to modulate a wide range of pathologic and physiologic pathways and can be manufactured under GMP conditions allowing for their application in the human inner ear. The role of inflammation in hearing loss with a focus on cochlear implantation is shown. How extracellular vesicles may provide a therapeutic option for complex inflammatory disorders of the inner ear is discussed. Additionally, manufacturing and regulatory issues that need to be addressed to develop EVs as advanced therapy medicinal product for use in the inner ear are outlined. (4) Conclusion: Given the complexities of inner ear injury, novel therapeutics such as extracellular vesicles could provide a means to modulate inflammation, stress pathways and apoptosis in the inner ear.

Human umbilical cord mesenchymal stem cells derived extracellular vesicles regulate acquired immune response of lupus mouse in vitro

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple systems. Immunopathology believes that abnormal T cell function and excessive production of autoantibodies by B cells are involved in multi-organ damage. Human umbilical cord mesenchymal stem cells (hUCMSCs) therapies have endowed with promise in SLE, while the function of MSC-derived extracellular vesicles (MSC-EVs) was still unclear. Extracellular vesicles (EVs) are subcellular components secreted by a paracellular mechanism and are essentially a group of nanoparticles. EVs play a vital role in cell-to-cell communication by acting as biological transporters. New evidence has shown beneficial effects of MSC-EVs on autoimmune diseases, such as their immunomodulatory properties. In this study, we investigated whether hUCMSCs derived extracellular vesicles (hUCMSC-EVs) could regulate abnormal immune responses of T cells or B cells in SLE. We isolated splenic mononuclear cells from MRL/lpr mice, a classical animal model of SLE. PBS (Phosphate-buffered saline), 2 × 10⁵ hUCMSCs, 25 µg/ml hUCMSC-EVs, 50 µg/ml hUCMSC-EVs were co-cultured with 2 × 10⁶ activated splenic mononuclear cells for 3 days in vitro, respectively. The proportions of CD4⁺ T cell subsets, B cells and the concentrations of cytokines were detected. Both hUCMSCs and hUCMSC-EVs inhibited CD4⁺ T cells, increased the production of T helper (Th)17 cells, promoted the production of interleukin (IL)-17 and transforming growth factor beta1 (TGF-β1) (P < 0.05), although they had no significant effects on Th1, Th2, T follicular helper (Tfh), regulatory T (Treg) cells and IL-10 (P > 0.05); only hUCMSCs inhibited CD19⁺ B cells, promoted the production of interferon-gamma (IFN-γ) and IL-4 (P < 0.05). hUCMSCs exert immunoregulatory effects on SLE at least partially through hUCMSC-EVs in vitro, therefore, hUCMSC-EVs play novel and potential regulator roles in SLE.