Abstract
Human cytomegalovirus (HCMV) is a ubiquitous pathogen which periodically reactivates, causing severe clinical consequences in immunosuppressed patients, organ and stem cell transplant recipients or newborn babies with congenital infections. HCMV infection stimulates the expression of several proinflammatory cytokines, which may contribute to the pathogenesis of the infection. Rho GTPases mediate cytokine expression while increasing evidence implicates them in important aspects of HCMV life cycle. Here, we studied the role of RhoA on the interleukin 11 (IL-11) release in HCMV-infected fibroblasts. Human fibroblasts, either endogenously expressing or silenced for RhoA, were infected by HCMV or UV-inactivated virus and IL-11 transcription and secretion were evaluated. We found that HCMV lytic infection increased the IL-11 levels, both in terms of transcription and translation. Both infectious and non-infectious HCMV particles were able to induce the IL-11 production. The depletion of RhoA resulted in an even higher release of IL-11, revealing the implication of this specific Rho isoform in this biological event. Finally, infection of cells in the presence of the HCMV DNA replication inhibitor, ganciclovir, significantly reduced the secretion of IL-11, strongly associating its induction with active viral DNA replication. Collectively, these data demonstrate, for the first time, a novel role of RhoA GTPase during HCMV lytic infection, regulating the activation of an immune response through IL-11.