Umbilical Cord Mesenchymal Stem Cells Ameliorate Kidney Injury in MRL/Ipr Mice Through the TGF-β1 Pathway

Unleashing the Potential: Exploring the Application and Mechanism of Mesenchymal Stem Cells in Autoimmune Diseases

Autoimmune diseases (AIDs) occur when the immune system mistakenly attacks the body's own antigens. Traditionally, these conditions are treated with nonspecific immunosuppressive therapies, including corticosteroids, immunosuppressants, biological agents, and human immunoglobulins. However, these treatments often fail to achieve optimal outcomes, especially for patients with severe cases. Mesenchymal stem cells (MSCs) present a promising alternative due to their robust self-renewal capabilities and multidirectional differentiation potential. MSCs are easily accessible, exhibit low immunogenicity, and can help reduce graft rejection. MSCs can inhibit T cell proliferation, reduce proinflammatory T cells, inhibit B cell differentiation, induce macrophage polarization towards the anti-inflammatory M2 phenotype, and suppress activity of natural killer (NK) cells and dendritic cells (DCs). Additionally, MSCs can regulate T cells, macrophages, and fibroblast-like synoviocytes (FLS) by releasing microRNA (miRNA) through exosomes or extracellular vesicles (EVs), thus providing therapeutic benefits for various diseases. Numerous clinical trials have highlighted the therapeutic benefits of MSCs in treating various AIDs, leading to increased interest in MSC transplantation. This review summarizes the current applications and mechanisms of action of MSCs in the treatment of AIDs.

Umbilical Cord Mesenchymal Stem Cells Attenuate Podocyte Injury in Diabetic Nephropathy Rats by Inhibiting Angpltl4/Integrin β3 in the Glomerulus

In this study, we investigated the therapeutic effects and mechanisms of umbilical cord mesenchymal stem cells (UCMSCs) in diabetic nephropathy (DN) ZDF (FA/FA) rats. The therapeutic effects were assessed by renal function tests, the urinary albumin-creatinine ratio, PAS staining, electron microscopy, and TGF-β1 expression in renal tissue. Subsequently, podocyte injury in renal tissue was detected by immunofluorescence staining for podocin. To further explore the underlying mechanism, serum Angptl4 levels were measured, and Angptl4, integrin β3, fibronectin, and podocin levels in renal tissue were analysed by Western blotting. In vitro, podocytes are stimulated with high glucose and then treated with UCMSCs, and podocyte activity and the expression of synaptopodin, Angptl4, and integrin β3 were observed. UCMSC significantly improve renal function, pathological injury, and podocyte injury in the ZDF (FA/FA) rats. Western blot revealed increased expression of Angptl4, integrin β3, and fibronectin in renal tissues of the DN group, and UCMSC treatment significantly downregulated those proteins. However, UCMSC showed no effects on serum Angptl4 concentration. Podocin expression in renal tissues was significantly restored by UCMSC treatment. In vitro, podocyte activity was decreased after high glucose stimulation and improved by UCMSC treatment. UCMSC restored the expression of synaptopodin, and Angptl4 and downstream integrin β3 were also inhibited. Our study suggested that UCMSC therapy could improve renal function and renal pathological changes in ZDF (FA/FA) rats. In addition, inhibition of the Angptl4/integrin β3 pathway is the potential mechanism by which UCMSC attenuates podocyte injury in the DN model.

Novel approach to alleviate lupus nephritis: targeting the NLRP3 inflammasome in CD8+CD69+CD103+ TRM cells

BACKGROUND

Renal CD8+ tissue-resident memory T (TRM) cells display prolonged survival and activity in lupus nephritis (LN), exacerbating renal pathology. NLRP3 regulates the T cell response. This study explored the impact of NLRP3 inflammasome activity on the regulatory functions of TRM cells in LN.

METHODS

NLRP3 inflammasome activity in renal CD8+ TRM cells from lupus-prone MRL/lpr mice and in vitro induced human CD8+CD103+ T cells was assessed by quantifying NLRP3, caspase-1, gasdermin D (GSDMD), and IL-1β levels using flow cytometry, ELISA, and western blotting analysis. The specific NLRP3 inhibitor MCC950, caspase-1 inhibitor Ac-YVAD-cmk, and NF-κB inhibitor JSH23 were utilized to delineate the role of NLRP3 in modulating the pathogenicity of CD8+ TRM cells in LN.

RESULTS

Activation of the NLRP3 inflammasome was confirmed in renal CD8+CD69+CD103+ TRM cells derived from mice with LN and in vitro-induced human CD8+CD103+ TRM-like cells. MCC950 curtailed the infiltration and activity of CD8+CD69+CD103+ TRM cells and enhanced renal outcomes. MCC950 also suppressed the maturation and functional capabilities of CD8+CD103+ T cells in a manner reliant on inflammasome activity in vitro. IL-1β promoted the expression of TGF-βRII in CD8+ T cells via the NF-κB pathway.

CONCLUSIONS

NLRP3 inflammasome activity in renal CD8+CD69+CD103+ TRM cells contributes to LN pathogenesis by regulating cell differentiation and effector functions. Therapeutically targeting the NLRP3 inflammasome could significantly mitigate CD8+CD69+CD103+ TRM cell-mediated renal damage in LN.

Astragaloside IV relieves passive heymann nephritis and podocyte injury by suppressing the TRAF6/NF-κb axis

The pathogenesis of membranous nephropathy (MN) involves podocyte injury that is attributed to inflammatory responses induced by local immune deposits. Astragaloside IV (AS-IV) is known for its robust anti-inflammatory properties. Here, we investigated the effects of AS-IV on passive Heymann nephritis (PHN) rats and TNF-α-induced podocytes to determine the underlying molecular mechanisms of MN. Serum biochemical parameters, 24-h urine protein excretion and renal histopathology were evaluated in PHN and control rats. The expression of tumor necrosis factor receptor associated factor 6 (TRAF6), the phosphorylation of nuclear factor kappa B (p-NF-κB), the expression of associated proinflammatory cytokines (TNF-α, IL-6 and IL-1β) and the ubiquitination of TRAF6 were measured in PHN rats and TNF-α-induced podocytes. We detected a marked increase in mRNA expression of TNF-α, IL-6 and IL-1β and in the protein abundance of p-NF-κB and TRAF6 within the renal tissues of PHN rats and TNF-α-induced podocytes. Conversely, there was a reduction in the K48-linked ubiquitination of TRAF6. Additionally, AS-IV was effective in ameliorating serum creatinine, proteinuria, and renal histopathology in PHN rats. This effect was concomitant with the suppression of NF-κB pathway activation and decreased expression of TNF-α, IL-6, IL-1β and TRAF6. AS-IV decreased TRAF6 levels by promoting K48-linked ubiquitin conjugation to TRAF6, which triggered ubiquitin-mediated degradation. In summary, AS-IV averted renal impairment in PHN rats and TNF-α-induced podocytes, likely by modulating the inflammatory response through the TRAF6/NF-κB axis. Targeting TRAF6 holds therapeutic promise for managing MN.

Adipose-derived mesenchymal stem cells secrete extracellular vesicles: A potential cell-free therapy for canine renal ischaemia-reperfusion injury

BACKGROUND

Adipose-derived mesenchymal stem cells (ADMSCs) and their extracellular vesicles (EVs) are a promising source of therapies for ischaemia-reperfusion (IR) because of their potent anti-inflammatory and immunomodulatory properties.

OBJECTIVES

The aims of this study were to explore the therapeutic efficacy and potential mechanism of ADMSC-EVs in canine renal IR injury.

METHODS

Mesenchymal stem cells (MSCs) and EVs were isolated and characterised for surface markers. A canine IR model administered with ADMSC-EVs was used to evaluate therapeutic effects on inflammation, oxidative stress, mitochondrial damage and apoptosis.

RESULTS

CD105, CD90 and beta integrin ITGB were positively expressed in MSCs, while CD63, CD9 and intramembrane marker TSG101 were positively expressed in EVs. Compared with the IR model group, there was less mitochondrial damage and reduction in quantity of mitochondria in the EV treatment group. Renal IR injury led to severe histopathological lesions and significant increases in biomarkers of renal function, inflammation and apoptosis, which were attenuated by the administration of ADMSC-EVs.

CONCLUSIONS

Secretion of EVs by ADMSCs exhibited therapeutic potential in renal IR injury and may lead to a cell-free therapy for canine renal IR injury. These findings revealed that canine ADMSC-EVs potently attenuate renal IR injury-induced renal dysfunction, inflammation and apoptosis, possibly by reducing mitochondrial damage.

GDF-15: A Potential Biomarker and Therapeutic Target in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a rheumatic disease. Growth differentiation factor 15 (GDF-15) is a member of transforming growth factor-β superfamily. To date, association of GDF-15 with SLE pathogenesis is not clarified. This study discussed GDF-15 serum levels and gene polymorphisms in SLE patients and lupus mouse model further demonstrated the role of GDF-15 in lupus development. We conducted two independent case-control studies for SLE patients. One is to evaluate serum levels of GDF-15 in 54 SLE patients and 90 healthy controls, and the other one is to analyze gene polymorphisms of GDF-15 in 289 SLE patients and 525 healthy controls. Serum levels of GDF-15 were detected by ELISA. GDF-15 gene polymorphisms (rs1055150, rs1058587, rs1059519, rs1059369, rs1227731, rs4808793, and rs16982345) were genotyped by the Kompetitive Allele-Specific PCR (KASP) method. Addition of recombinant GDF-15 into pristane-induced lupus mice evaluated histological and serological changes. Results showed that serum levels of GDF-15 were overexpressed in SLE patients and associated with disease activity. Polymorphisms rs1055150, rs1059369, rs1059519, and rs4808793 of GDF-15 gene were related to SLE risk. Lupus mice showed splenomegaly, severe histological scores, and high levels of autoantibodies [antinuclear antibodies (ANA) and total immunoglobulin G (IgG)], whereas administration of GDF-15 into lupus mice reduced the histological changes. Percentages of CD8⁺, CD11b⁺, CD19⁺, CD11C⁺ cells, T_H2 cells, and pro-inflammatory cytokines (IL-1β, IL-2, IL-4, IL-21, and IL-22) were reduced after GDF-15 treatment in lupus mice. In conclusion, GDF-15 was related to lupus pathogenesis and inhibited lupus development.