Abstract
Polyomaviruses are associated with many diseases due to their ability to persistently infect the host. Since 2008, twelve new human polyomaviruses have been discovered.
Among the new species, Merkel cell polyomavirus (MCPyV) was identified as the etiological agent of skin Merkel cell carcinoma. Unfortunately, the cell type productively infected by MCPyV is unknown and therefore in vitro studies of the MCPyV are still a challenge.
Nevertheless, its closest related member, Murine polyomavirus (MPyV) has been used per decades as in vitro model to understand fundamental questions about the biology of polyomaviruses. We demonstrated that MPyV activates innate immunite responses via GAS-STING and TLR4.
It is known that the transcription factors, NF-Ƙβ and IRF3 are activated during launching of the above pathways. However, NF-Ƙβ is mainly activated by TLR4 for pro-inflammatory cytokines production and IRF3 by cGAS-STING for interferon (IFN) production.