The CLEC-2-podoplanin axis inhibits dendritic cells migration and prolongs allograft survival in mice.

BACKGROUND

Dendritic cell (DC) migration-triggered T cell activation is a pivotal event in transplant rejection. Previous studies have established a critical role of the C-type lectin receptor 2（CLEC-2）and podoplanin (PDPN) axis in regulating DC migration. We therefore hypothesized that targeting CLEC-2-PDPN axis could prolong allograft survival in mice by impairing DC migration.

MATERIALS AND

METHODS

Bioinformatics analysis was performed to assess differential CLEC-2 expression between allograft and isograft tissues and to identify potential associated biological processes. Bone marrow-derived dendritic cells (BMDCs) were generated from donor mice and treated with anti-CLEC-2 to inhibit CLEC-2 function. After LPS stimulation, surface expression of costimulatory molecules and MHC class II, as well as phagocytic capacity, were analyzed. Migration in response to PDPN and CCL19 gradients and the ability to stimulate T cell proliferation were evaluated using a Transwell assay. A murine skin allograft model (BALB/c to C57BL/6) was established. Then anti-PDPN was injected into recipient mice during transplantation. Graft survival was monitored, and pathological examination of grafts, flow cytometric analysis of draining lymph nodes (assessing DC migration and T cell activation/proliferation), and serum cytokine detection by ELISA were performed.

RESULTS

Bioinformatics analysis revealed that CLEC-2 was significantly upregulated in the allograft group. In vitro, CLEC-2 suppression had no significant effect on the expression of costimulatory molecules or phagocytosis in dendritic cells. However, it specifically inhibited PDPN-mediated migration and suppressed T cell proliferation in the Transwell assay. Anti-PDPN treatment significantly prolonged skin allograft survival and attenuated rejection in mice. Flow cytometry revealed a reduced proportion of migratory DCs, particularly of the cDC2 subset in the draining lymph nodes of treated mice. Furthermore, both CD4 + and CD8 +T cell proliferation and activation were markedly suppressed. ELISA results showed decreased serum levels of IL-18 and IL-1β, while elevated IL-10.

CONCLUSION

Targeting the CLEC-2-PDPN axis significantly prolongs murine allograft survival via the inhibiting DC migration and subsequent T-cell proliferative responses.