Infection with the human papillomaviruses (HPVs) is responsible for approximately 5% of all human cancers worldwide and represents a continuing threat to global public health. Although a prophylactic vaccine against HPV infection is available, it does not protect against all HPV types and is not accessible in most developing countries due to high costs. Moreover, a therapeutic vaccine to treat established HPV infections does not exist. How HPVs enter human cells to establish infection is poorly understood. In particular, one essential aspect of viral cell entry that remains understudied is the molecular mechanism of HPV interaction with the innate immune system prior to viral gene expression. The innate immune system can sense viral nucleic acids through pattern recognition receptors such as the Toll-like receptors (TLRs). TLR activation induces the expression of numerous antiviral genes and initiates adaptive immune responses. Whether TLRs can sense the HPV genome during viral entry into cells is unknown. One reason for this gap in our knowledge is the historical use o virus-like particles (VLPs), which are devoid of DNA, to study cellular immune responses to HPV infection. Here I propose to take advantage of authentic HPV virions generated in organotypic keratinocyte raft cultures to investigate the molecular mechanism of viral DNA recognition by the innate immune system. Specifically, I will explore whether the HPV genome can be sensed by TLR9 in plasmacytoid dendritic cells (pDCs) and cytosolic DNA sensors, such as cGAS, in keratinocytes. I will focus on these two cell types because keratinocytes are the in vivo target of HPV while pDCs are immune cells that specialize in antiviral recognition and defense within epithelial tissues. Better understanding of how HPV cell entry is sensed by the innate immune system will shed new light on a poorly understood aspect of infection and suggest novel immunotherapeutic strategies for preventing and treating papillomavirus infections.
Human papillomaviruses (HPVs) are sexually transmitted cancer viruses that cause almost 300,000 deaths worldwide every year. How infected cells recognize HPV during virus entry and transport, is unknown. Elucidating the mechanism of papillomavirus detection by infected cells will facilitate the development of novel immunotherapeutic strategies to prevent HPV spread among humans, treat established infections, and therefore reduce the global incidence of cancer.
| Lipovsky, Alex; Erden, Asu; Kanaya, Eriko et al. (2017) The cellular endosomal protein stannin inhibits intracellular trafficking of human papillomavirus during virus entry. J Gen Virol 98:2821-2836 |
