Rapamycin treated tol-dendritic cells derived from BM-MSCs reversed graft rejection in a rat liver transplantation model by inducing CD8+CD45RC-Treg

Rapamycin-modified CD169low/-tolDC promotes skin graft survival in mice via IL-10+Breg

Skin allografts are prone to rejection because of their high immunogenicity. By achieving immune tolerance, the long-term survival of skin allografts can be extended without the need for immunosuppressants or with only short-term low-dose dependency. Tolerogenic dendritic cells (tolDCs) show a strong potential for graft tolerance. We explored the mechanism whereby rapamycin-modified CD169low/-tolDCs regulate interleukin-10 (IL-10) B regulatory (IL-10+ Breg) cell production and mediate the long-term survival of skin allografts in mice. CD169low/-tolDCs were obtained through flow cytometry sorting after treating the mesenchymal stem cell (MSC)-derived dendritic cells with a low dose of GM-CSF. A treatment regimen combining preoperative stimulation and postoperative adoptive infusion of CD169low/-tolDCs was used to treat an acute rejection (AR) mouse skin transplantation model-the adoptive infusion group. An equivalent dose of saline was administered to the control group. Survival and graft rejection rates were assessed. Mixed lymphocyte culture, flow cytometry, immunohistochemistry (IHC), and western blotting (WB) were used to elucidate the expression of different IL-10+ Breg subsets in mice treated with adoptive infusion therapy and the molecular mechanisms whereby CD169low/-tolDCs induce IL-10+ Breg production to mediate tolerance. Adoptive infusion of CD169low/-tol DCs markedly prolonged the rejection time after skin transplantation in mice and promoted graft survival. A significant increase was observed in local blood flow signals in the transplanted skin, along with mild local inflammation. Flow cytometric analysis revealed a positive correlation between high expression of IL-10+ Breg and the changes in Foxp3+ Tregs in vivo, primarily enriched in the CD19 + CD24 + CD27+ mBreg and CD19 + CD23 + CD27-CD24+ Breg subsets, with higher levels of IgM expression. Significant differences were observed compared with control mice. CD79b/NF-κB pathway was found to be involved in Breg production. CD24, CD23, CD79, BTK, NF-κB p50/p65, CD40, and IKKα levels in the adoptive infusion group were significantly increased compared with those in the control group. Adoptive infusion of CD169low/-MSCs/tolDCs may activate the NF-κB pathway through CD79/BTK-dependent and CD40/IKKα-independent pathways, inducing high expression of IL-10 + Breg and promoting graft survival of mouse skin transplantation.

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.

Retinoic acid-inducible gene-1 knockdown induces immature properties in dendritic cells and prolongs the survival time of allograft mice

BACKGROUND

The mature state of dendritic cells (DCs) determines their ability to regulate immune responses. Retinoic acid-inducible gene-1 (RIG-1) plays a critical role in DC activation and maturation. RIG-1 activation triggers mitogen-activated protein kinase and nuclear factor-kappa B signal transduction. In this study, we aimed to investigate the effects of inhibiting RIG-1 expression in DCs and its potential in inducing immune tolerance.

METHODS

DCs were transduced with the recombinant lentiviral vector (Lv) to inhibit RIG-1 expression. A murine islet and skin transplantation model were constructed to find out whether DC-DDX58-RNAi could prolong allograft survival. The phenotypes of DCs and T-cells were analyzed using flow cytometry. Cytokines in serum were detected by the enzyme-linked immunosorbent assay. Protein levels were determined by Western blot.

RESULTS

RIG-1-deficient DCs had low expression of costimulatory molecules and major histocompatibility complex and a strong phagocytic ability. DC-DDX58-RNAi induced regulatory T cell differentiation in the transplant recipient spleens. The DC-DDX58-RNAi-treated recipients showed satisfactory islet allograft function and longer survival time.

CONCLUSION

Inhibition of RIG-1 with DDX58-RNAi prevented the activation and maturation of the DCs, affected T cell differentiation, protected the biological function of the allograft, and prolonged graft survival. These findings may have important therapeutic implications for new immunomodulatory regimens.

Comparative effects of hepatocyte growth factor and tacrolimus on acute liver allograft early tolerance

Allostimulated CD8+ T cells (aCD8+ T cells), as the main mediators of acute liver rejection (ARJ), are hyposensitive to apoptosis due to the inactivation of death receptor FAS-mediated pathways and fail to allow tolerance induction, eventually leading to acute graft rejection. Although tacrolimus (FK506), the most commonly used immunosuppressant (IS) in the clinic, allows tolerance induction, its use is limited because its target immune cells are unknown and it is associated with increased incidences of malignancy, infection, and nephrotoxicity, which substantially impact long-term liver transplantation (LTx) outcomes. The dark agouti (DA)-to-Lewis rat LTx model is a well-known ARJ model and was hence chosen for the present study. We show that both hepatocyte growth factor (HGF) (cHGF, containing the main form of promoting HGF production) and recombinant HGF (h-rHGF) exert immunoregulatory effects mainly on allogeneic aCD8+ T cell suppression through FAS-mediated apoptotic pathways by inhibiting cMet to FAS antagonism and Fas trimerization, leading to acute tolerance induction. We also showed that such inhibition can be abrogated by treatment with neutralizing antibodies against cMet (HGF-only receptor). In contrast, we did not observe these effects in rats treated with FK506. However, we observed that the effect of anti-rejection by FK506 was mainly on allostimulated CD4+ T cell (aCD4+ T cell) suppression and regulatory T cell (Treg) promotion, in contrast to the mechanism of HGF. In addition, the protective mechanism of HGF in FK506-mediated nephrotoxicity was addressed. Therefore, HGF as a tolerance inducer, whether used in combination with FK506 or as monotherapy, may have good clinical value. Additional roles of these T-cell subpopulations in other biological systems and studies in these fields will also be meaningful.

Ni-doped MoS2 embedded in natural wood containing porous cellulose for piezo-catalytic degradation of tetracycline

Wood is a natural material with low cost and easy recovery, which porous, layered, excellent structure and mechanical properties make it possible to apply in wastewater treatment. We have successfully grown MoS₂ on natural wood containing porous cellulose and introduced the high conductivity circuit path provided by Ni nanoparticles to construct a new piezoelectric three-dimensional wood block for the efficient degradation of tetracycline. Ni/MoS₂/Wood exhibited excellent piezo-catalytic degradation performance, and the degradation rate of tetracycline reached 95.96 % (k = 0.0411 min^-1) under ultrasonic vibration. After 5 cycles, the degradation rate still reached 90.20 %. In addition, Ni/MoS₂/Wood was used as the reactor filler to degrade tetracycline through piezoelectric response triggered by hydrodynamic force, and the degradation rate reached 90.27 % after 60 min. Further, the mechanism and the possible degradation pathways of tetracycline degradation were proposed. This low-cost, recyclable and stable three-dimensional wood block piezoelectric material provides a new idea for the practical application of wastewater treatment.