CD109 is novel KSHV entry receptor in human endothelial cells and enhances infection during cellular senescence

The aging process is characterized by cellular functional decline and increased susceptibility to infections. Understanding the association between virus infection and aging is crucial for developing effective strategies against viral infections in older individuals. Kaposi's sarcoma-associated herpesvirus (KSHV) infection increases the risk of Kaposi's sarcoma, a vascular cancer prevalent among the elderly without HIV infection. However, the relationship between KSHV pathogenesis and cellular senescence remains unknown. Here, we demonstrate that KSHV infectivity is significantly increased in senescent human endothelial cells due to enhanced binding of virions to cell surface. Proteomic analysis identified caveolin-1 and CD109 that promote KSHV infection and were significantly upregulated in senescent cells. In particular, CD109 is expressed on cell surface and directly interacts with KSHV virions to enhance KSHV infection. Knockout of CD109 abolished while overexpression of CD109 promote KSHV binding to cell surface, and infectivity. These results identify CD109 as a novel KSHV entry receptor that enhances KSHV infection in senescent cells, which might in part explain the higher sensitivity of elder subjects to KSHV infection and Kaposi's sarcoma.