Cofilin hyperactivation in HIV infection and targeting the cofilin pathway using an anti-α₄β₇ integrin antibody

A functional HIV cure requires immune reconstitution for lasting viremia control. A major immune dysfunction persisting in HIV infection is the impairment of T helper cell migration and homing to lymphoid tissues such as GALTs (gut-associated lymphoid tissues). ART (antiretroviral therapy) does not fully restore T cell motility for tissue repopulation. The molecular mechanism dictating this persistent T cell dysfunction is not understood. Cofilin is an actin-depolymerizing factor that regulates actin dynamics for T cell migration. Here, we demonstrate that blood CD4 T cells from HIV-infected patients (n = 193), with or without ART, exhibit significantly lower levels of cofilin phosphorylation (hyperactivation) than those from healthy controls (n = 100; ratio, 1.1:2.3; P < 0.001); cofilin hyperactivation is also associated with poor CD4 T cell recovery following ART. These results suggest an HIV-mediated systemic dysregulation of T cell motility that cannot be repaired solely by ART. We further demonstrate that stimulating blood CD4 T cells with an anti-human α₄β₇ integrin antibody can trigger signal transduction and modulate the cofilin pathway, partially restoring T cell motility in vitro. However, we also observed that severe T cell motility defect caused by high degrees of cofilin hyperactivation was not repairable by the anti-integrin antibody, demonstrating a mechanistic hindrance to restore immune functions in vivo. Our study suggests that cofilin is a key molecule that may need to be therapeutically targeted early for T cell tissue repopulation, immune reconstitution, and immune control of viremia.