BACKGROUND: Previous studies have shown that peptides encoded by noncoding RNAs (ncRNAs) can be used as peptide drugs to alleviate diseases. We found that microRNA-31 (miR-31) is involved in the regulation of hypertension and that the peptide miPEP31, which is encoded by the primary transcript of miR-31 (pri-miR-31), can inhibit miR-31 expression. However, the role and mechanism of miPEP31 in hypertension have not been elucidated.
METHODS: miPEP31 expression was determined by western blot analysis. miPEP31-deficient mice (miPEP31-/-) were used, and synthetic miPEP31 was injected into Ang II-induced hypertensive mice. Blood pressure was monitored through the tail-cuff method. Histological staining was used to evaluate renal damage. Regulatory T (Treg) cells were assessed by flow cytometry. Differentially expressed genes were analysed through RNA sequencing. The transcription factors were predicted by JASPAR. Luciferase reporter and electrophoretic mobility shift assays (EMSAs) were used to determine the effect of pri-miR-31 on the promoter activity of miPEP31. Images were taken to track the entry of miPEP31 into the cell.
RESULTS: miPEP31 is endogenously expressed in target organs and cells related to hypertension. miPEP31 deficiency exacerbated but exogenous miPEP31 administration mitigated the Ang II-induced systolic blood pressure (SBP) elevation, renal impairment and Treg cell decreases in the kidney. Moreover, miPEP31 deletion increased the expression of genes related to Ang II-induced renal fibrosis. miPEP31 inhibited the transcription of miR-31 and promoted Treg differentiation by occupying the Cebpα binding site. The minimal functional domain of miPEP31 was identified and shown to regulate miR-31.
CONCLUSIONS: miPEP31 was identified as a potential therapeutic peptide for treating hypertension by promoting Treg cell differentiation in vivo. Mechanistically, we found that miPEP31 acted as a transcriptional repressor to specifically inhibit miR-31 transcription by competitively occupying the Cebpα binding site in the pri-miR-31 promoter. Our study highlights the significant therapeutic effect of miPEP31 on hypertension and provides novel insight into the role and mechanism of miPEPs.

BACKGROUND: Mesenchymal stem cells (MSCs) demonstrate a wide range of therapeutic capabilities in the treatment of inflammatory bowel disease (IBD). The intraperitoneal injection of MSCs has exhibited superior therapeutic efficacy on IBD than intravenous injection. Nevertheless, the precise in vivo distribution of MSCs and their biological consequences following intraperitoneal injection remain inadequately understood. Additional studies are required to explore the correlation between MSCs distribution and their biological effects.
METHODS: First, the distribution of human umbilical cord MSCs (hUC-MSCs) and the numbers of Treg and Th17 cells in mesenteric lymph nodes (MLNs) were analyzed after intraperitoneal injection of hUC-MSCs. Subsequently, the investigation focused on the levels of transforming growth factor beta1 (TGF-β1), a key cytokine to the biology of both Treg and Th17 cells, in tissues of mice with colitis, particularly in MLNs. The study also delved into the impact of hUC-MSCs therapy on Treg cell counts in MLNs, as well as the consequence of TGFB1 knockdown hUC-MSCs on the differentiation of Treg cells and the treatment of IBD.
RESULTS: The therapeutic effectiveness of intraperitoneally administered hUC-MSCs in the treatment of colitis was found to be significant, which was closely related to their quick migration to MLNs and secretion of TGF-β1. The abundance of hUC-MSCs in MLNs of colitis mice is much higher than that in other organs even the inflamed sites of colon. Intraperitoneal injection of hUC-MSCs led to a significant increase in the number of Treg cells and a decrease in Th17 cells especially in MLNs. Furthermore, the concentration of TGF-β1, the key cytokine for Treg differentiation, were also found to be significantly elevated in MLNs after hUC-MSCs treatment. Knockdown of TGFB1 in hUC-MSCs resulted in a noticeable reduction of Treg cells in MLNs and the eventually failure of hUC-MSCs therapy in colitis.
CONCLUSIONS: MLNs may be a critical site for the regulatory effect of hUC-MSCs on Treg/Th17 cells and the therapeutic effect on colitis. TGF-β1 derived from hUC-MSCs promotes local Treg differentiation in MLNs. This study will provide new ideas for the development of MSC-based therapeutic strategies in IBD patients.

BACKGROUND: Guillain-Barré syndrome (GBS) is an auto-inflammatory peripheral nerve disease. Dendritic cell-mediated T cell polarization is of pivotal importance in demyelinating lesions of peripheral nerves and nerve roots. However, the regulatory function of VX-509 (Decernotinib)-modified tolerogenic dendritic cells (VX-509-tolDCs) during immune remodeling following GBS remains unclear. Here, we used experimental autoimmune neuritis (EAN) as a model to investigate these aspects of GBS.
METHODS: DCs were treated with varying concentrations of VX-509 (0.25, 1, and 4 μM) or served as a control using 10-8 M 1,25-(OH)2D3. Flow cytometry was employed to assess the apoptosis, phenotype, and capacity to induce T cell responses of the treated DCs. In the in vivo experiments, EAN mice received administration of VX-509-tolDCs or 1,25-(OH)2D3-tolDCs via the tail vein at a dose of 1x106 cells/mouse on days 5, 9, 13, and 17.
RESULTS: VX-509 inhibited the maturation of DCs and promoted the development of tolDCs. The function of antigen-specific CD4 + T cells ex vivo was influenced by VX-509-tolDCs. Furthermore, the adoptive transfer of VX-509-tolDCs effectively alleviated inflammatory demyelinating lesions in EAN by promoting Th17/Treg (T helper 17 and regulatory T cells) rebalance.
CONCLUSIONS: The adoptive transfer of VX-509-tolDCs alleviated inflammatory demyelinating lesions in a mouse model of GBS, known as the EAN mouse, by partially restoring the balance between Treg and Th17 cells.

Intravenous infusion has been used as the method of cell delivery in many preclinical studies as well as in some early clinical trials. Among its advantages are broad distribution, ability to handle a large-volume infusion, and ease of access. Progenitor cells used in cell-based therapy act through their secretomes, rather than their ability to differentiate into lineage-specific cell type. Since not all progenitor cells have similar secretome potency, the innate abilities of the secretome of cells used in clinical trials will obviously dictate their effectiveness. We previously found that cardiac neonatal mesenchymal stromal cells (nMSCs) are more effective in repairing the infarcted myocardium compared to adult mesenchymal stromal cells (aMSCs) due to their robust secretome (Sharma et al Circulation Research 120:816-834, 2017). In this study, we explored the efficacy of intravenous (IV) delivery of nMSCs for myocardial recovery. Six-week-old male Brown Norway rats underwent acute MI by ligation of the left anterior descending artery, followed by IV infusion of cell dose 5 × 106 nMSCs/rat body weight (kg) or saline on days 0 and 5. We found that cardiac parameters in the rodent ischemia model improved 1 month after nMSCs infusion, and the result is comparable with the intramyocardial injection of nMSCs. Tracking the infused cells in target organ revealed that their movement after IV delivery was mediated by the cell surface receptor CD44. Systemic injection of nMSCs stimulated immunomodulatory responses specifically by increasing FoxP3+ T-regulatory cell influenced anti-inflammatory macrophages (M2) in heart. These data demonstrate that nMSCs promote immunogenic tolerance via CD44-driven T-reg/M2 stimulation that helps nMSCs for longer viability in the injured myocardium for better functional recovery. Our data also demonstrate a rationale for a clinical trial of IV infusion of nMSCs to promote cardiac function improvement in the ischemic patients.

Interstitial lung disease (ILD) is a common and fatal manifestation of antisynthetase syndrome (ASS). The aim of this study was to provide new insight into investigate peripheral blood lymphocytes, CD4+ T cells, cytokine levels and their relation to the clinical profile of untreated patients with ASS-ILD. The retrospective study population included thirty patients diagnosed with ASS-ILD and 30 healthy controls (HCs). Baseline clinical and laboratory data were collected for all subjects, including peripheral blood lymphocyte, CD4+ T cell subsets measured by flow cytometry, and serum cytokine levels measured by multiple microsphere flow immunofluorescence. Their correlations with clinical and laboratory findings were analyzed by Pearson\'s or Spearman\'s correlation analysis. In addition, the Benjamini-Hochberg method was used for multiple correction to adjust the p-values. Patients with ASS-ILD had lower CD8+ T cells, higher proportion of Th17 cells and Th17/Treg ratio than HCs. Serum cytokine levels (IL-1β, IL-6, IL-12, IL-17, IL-8, IL-2, IL-4, IL-10, TNF-α and IFN-γ) were higher in patients with ASS-ILD than HCs. Moreover, Th17/Treg ratio was negatively correlated with diffusing capacity of carbon monoxide (DLCO)%. Our study demonstrated abnormalities of immune disturbances in patients with ASS-ILD, characterized by decreased CD8+ T cells and an increased Th17/Treg ratio, due to an increase in the Th17 cells. These abnormalities may be the immunological mechanism underlying the development of ILD in ASS.

Breast cancer poses a global health challenge, yet the influence of ethnicity on the tumor microenvironment (TME) remains understudied. In this investigation, we examined immune cell infiltration in 230 breast cancer samples, emphasizing diverse ethnic populations. Leveraging tissue microarrays (TMAs) and core samples, we applied multiplex immunofluorescence (mIF) to dissect immune cell subtypes across TME regions. Our analysis revealed distinct immune cell distribution patterns, particularly enriched in aggressive molecular subtypes triple-negative and HER2-positive tumors. We observed significant correlations between immune cell abundance and key clinicopathological parameters, including tumor size, lymph node involvement, and patient overall survival. Notably, immune cell location within different TME regions showed varying correlations with clinicopathologic parameters. Additionally, ethnicities exhibited diverse distributions of cells, with certain ethnicities showing higher abundance compared to others. In TMA samples, patients of Chinese and Caribbean origin displayed significantly lower numbers of B cells, TAMs, and FOXP3-positive cells. These findings highlight the intricate interplay between immune cells and breast cancer progression, with implications for personalized treatment strategies. Moving forward, integrating advanced imaging techniques, and exploring immune cell heterogeneity in diverse ethnic cohorts can uncover novel immune signatures and guide tailored immunotherapeutic interventions, ultimately improving breast cancer management.

OBJECTIVE: To study whether subcutaneously embedding xenogeneic protein threads or synthetic polymer absorbable threads can improve obesity phenotypes and metabolic conditions, and to further explore its underlying mechanism.
METHODS: Thirty-six 8-week-old ob/ob mice were randomly allocated to three groups, respectively, receiving catgut embedding, PGA thread embedding or sham treatment bilaterally to the groin. Individual parameters including weight, food intake, and core temperature are recorded and metabolism assessment, energy expenditure analysis, and PET/CT scanning are also performed at fixed timepoints. After surgical incision, the inguinal white adipose tissue was histologically examined and its expression profile was tested and compared among groups 4 weeks and 12 weeks after operation.
RESULTS: Catgut embedding reduced weight gain and improved metabolic status in ob/ob mice. Browning of bilateral inguinal WAT (white adipose tissue) was induced after catgut embedding, with massive infiltration of Treg cells and M2 macrophages in the tissue slices of fat pads. IL-10 and TGF-β released by Treg cells targeted macrophages and the induced M2 macrophages increased the expression of thermogenic and anti-inflammatory genes in fat. The secretion of catecholamines by polarized M2 macrophages led to the activation of β3-AR-related pathways in adipocytes and the browning of adipose tissue.
CONCLUSIONS: Abdominal subcutaneous catgut embedding has the potential to combat obesity through the induction of WAT browning mediated by infiltrated Treg cells and macrophages.

No effective treatments can ameliorate symptoms of long COVID patients. Our study assessed the safety and efficacy of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) in the treatment of long COVID patients. Ten long COVID patients were enrolled and received intravenous infusions of UC-MSCs on Days 0, 7, and 14. Adverse events and clinical symptoms were recorded, and chest-high-resolution CT (HRCT) images and laboratory parameters were analyzed. During UC-MSCs treatment and follow-up, we did not observe serious adverse events, the symptoms of long COVID patients were significantly relieved in a short time, especially sleep difficulty, depression or anxiety, memory issues, and so forth, and the lung lesions were also repaired. The routine laboratory parameters did not exhibit any significant abnormalities following UC-MSCs transplantation (UMSCT). The proportion of regulatory T cells gradually increased, but it was not statistically significant until 12 months. The proportion of naive B cells was elevated, while memory B cells, class-switched B-cells, and nonswitched B-cells decreased at 1 month after infusion. Additionally, we observed a transient elevation in circulating interleukin (IL)-6 after UMSCT, while tumor necrosis factor (TNF)-α, IL-17A, and IL-10 showed no significant changes. The levels of circulating immunoglobulin (Ig) M increased significantly at month 2, while IgA increased significantly at month 6. Furthermore, the SARS-CoV-2 IgG levels remained consistently high in all patients at Month 6, and there was no significant decrease during the subsequent 12-month follow-up. UMSCT was safe and tolerable in long COVID patients. It showed potential in alleviating long COVID symptoms and improving interstitial lung lesions.

TPO receptor agonists (TPO-RAs) are a class of clinical second-line regimens for the treatment of primary immune thrombocytopenia (ITP). It can promote megakaryocyte maturation and increase platelet production, but its effect on immunosuppressive cells in patients with ITP has not been explored. Sixty-two ITP patients and 34 healthy controls (HCs) were included in this study. The proportion and functions of myeloid-derived immunosuppressive cells (MDSCs) in ITP patients and HCs were investigated. We found that the proportion and function of MDSCs in ITP patients treated with TPO-RAs were significantly higher than those treated with glucocorticoids (GCs), which was correlated with the clinical efficacy. The proportion and function of cytotoxic Th1 cells and CD8+T cells decreased, while the proportion and immunosuppressive function of Treg cells increased in ITP patients treated with TPO-RAs. We further proved, through MDSC depletion tests, that the inhibitory effect of MDSCs on Th1 cells and the promotion of Treg cells in the original immune micro-environment of GCs-treated ITP patients were impaired; however, these MDSCs\' functions were improved in TPO-RAs-treated patients. Finally, we found that the KLF9 gene in MDSCs cells of ITP patients treated with TPO-RAs was down-regulated, which contribute to the higher mRNA expression of GADD34 gene and improved function of MDSCs. These results demonstrate a novel mechanism of TPO-RAs for the treatment of ITP through the assessment of MDSCs and their subsequent impact on T cells, which provides a new basis for TPO-RAs as first-line treatment approach to the treatment of ITP.

In the last decade, cell therapies have revolutionized the treatment of some diseases, earning the definition of being the \"third pillar\" of therapeutics. In particular, the infusion of regulatory T cells (Tregs) is explored for the prevention and control of autoimmune reactions and acute/chronic allograft rejection. Such an approach represents a promising new treatment for autoimmune diseases to recover an immunotolerance against autoantigens, and to prevent an immune response to alloantigens. The efficacy of the in vitro expanded polyclonal and antigen-specific Treg infusion in the treatment of a large number of autoimmune diseases has been extensively demonstrated in mouse models. Similarly, experimental work documented the efficacy of Treg infusions to prevent acute and chronic allograft rejections. The Treg therapy has shown encouraging results in the control of type 1 diabetes (T1D) as well as Crohn\'s disease, systemic lupus erythematosus, autoimmune hepatitis and delaying graft rejection in clinical trials. However, the best method for Treg expansion and the advantages and pitfalls with the different types of Tregs are not fully understood in terms of how these therapeutic treatments can be applied in the clinical setting. This review provides an up-to-date overview of Treg infusion-based treatments in autoimmune diseases and allograft transplantation, the current technical challenges, and the highlights and disadvantages of this therapeutic approaches.\"