Caveolin-1–Mediated Negative Signaling Plays a Critical Role in the Induction of Regulatory Dendritic Cells by DNA and Protein Coimmunization

Abstract

Induction of Ag-specific regulatory T cells (iTregs) by vaccination is a promising strategy for treating autoimmune diseases. We previously demonstrated that DNA and protein covaccination converted naive T cells to Ag-specific iTregs by inducing CD11c+CD40lowIL-10+ regulatory dendritic cells (DCregs). However, it is unclear how coimmunization induces the DCregs. In this paper, we report that the event is initiated by coentry of sequence-matched DNA and protein immunogens into the same DC via caveolae-mediated endocytosis, which leads to inhibition of phosphorylation of caveolin-1 (Cav-1), the main component of caveolae, and upregulation of Tollip. This triggers downstream signaling that upregulates suppressor of cytokine signaling 1 and downregulates NF-κB and STAT-1α. Silencing either Cav-1 or Tollip blocks the negative signaling, leading to upregulated expression of CD40, downregulated production of IL-10, and loss of iTreg-inducing function. We further show that DCregs can be induced in culture from primary DCs and JAWS II DC lines by feeding them sequence-matched DNA and protein immunogens. The in vitro-generated DCregs are effective in ameliorating autoimmune and inflammatory diseases in several mouse models. Our study thus suggests that DNA and protein coimmunization induces DCregs through Cav-1– and Tollip-mediated negative signaling. It also describes a novel method for generating therapeutic DCregs in vitro.

Pleurotus ferulae water extract enhances the maturation and function of murine bone marrow-derived dendritic cells through TLR4 signaling pathway

“…Many studies showed that polysaccharides from TCM increased not only IL-12 but also IL-10 [34,43,44]. IL-10 modulates DC functions to suppress immune responses through induction of Tregs [45,46]. In contrast, our results showed that PFWE did not induce IL-10 production.…”

Herpes Simplex Virus 1 Suppresses the Function of Lung Dendritic Cells via Caveolin-1

“…DC2.4 is a DC cell line from C57BL/6 mice. Cav-1 knockdown DC2.4 cells and Cav-1 overexpressing DC2.4 cells were generated as previously described (23). Vero cells and DC2.4 cell lines were maintained in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% heat-inactivated fetal bovine serum (FBS) and 1% penicillin-streptomycin at 37°C with 5% CO 2 .…”

“…Although best known in lipid metabolism, roles for Cav-1 in the internalization of pathogens, signal transduction, host defenses, and suppression of inflammatory responses have also been indicated by numerous studies (20)(21)(22). Viral entry into cells occurs by clathrin, caveolae, or receptor-mediated pathways (23)(24)(25). However, recent studies revealed that simian virus 40 (SV40) enters cells via an atypical caveolae-mediated endocytic pathway, forming a new compartment called a caveosome (26,27).…”

Myocardial Tissue Caveolae

“…Immature or induced regulatory DCs (DC reg ) can promote tolerance by converting naïve T cells into the CD4+Foxp3+ regulatory T cells (157). DC differentiation into DC reg requires DNA and protein cotreatment and this is inhibited by the activation of Cav-1 and increased Tollip protein to initiate negative signaling, which leads to downregulation of STAT-1α and NF-κB, and expression of the DC reg phenotype (97). In this study, Cav-1/caveolae mediated couptake of DNA and protein immunogens via endocytosis and Cav-1 activation by phosphorylation to form a negative signaling complex to suppress IRAK-1's kinase activity (119) suggesting that Cav-1 plays a critical role in modulation of the DC phenotype and function.…”