Physalin F is a natural blocker of CaV2.3 (R-type) and CaV2.2 (N-type) voltage-gated calcium channels.It is a secosteroid with potent anti-inflammatory and immunomodulatory activities. Physalin F induces apoptosis of PBMC, decreasing the spontaneous proliferation and cytokine production caused by Human T-lymphotropic virus type 1 (HTLV-1) infection

Physalin F is a secosteroid with potent anti-inflammatory and immunomodulatory activities.?A concentration-dependent inhibition of spontaneous proliferation of PBMC from HAM/TSP subjects was observed in the presence of physalin F, as evaluated by (3)H-thymidine uptake.?The IC50 for physalin F was 0.97 0.11 μM.?Flow cytometry analysis using Cytometric Bead Array (CBA) showed that physalin F (10 μM) significantly reduced the levels of IL-2, IL-6, IL-10, TNF-α and IFN-γ, but not IL-17A, in supernatants of PBMC cultures.?Next, apoptosis induction was addressed by using flow cytometry to evaluate annexin V expression.?Treatment with physalin F (10 μM) increased the apoptotic population of PBMC in HAM/TSP subjects.?Transmission electron microscopy analysis of PBMC showed that physalin F induced ultrastructural changes, such as pyknotic nuclei, damaged mitochondria, enhanced autophagic vacuole formation, and the presence of myelin-like figures.?In conclusion, physalin F induces apoptosis of PBMC, decreasing the spontaneous proliferation and cytokine production caused by HTLV-1 infection.