NIH Research Festival
HIV-1 assembly occurs at specific membrane microdomains of the plasma membrane (PM) called lipid rafts, regions typically high in cholesterol, sphingomyelin, and ceramide. Sphingomyelinases (SMases) are key enzymes that produce ceramide through the hydrolysis of sphingomyelin. Neutral sphingomyelinase 2 (nSMase2) is the primary sphingomyelinase in mammalian cells that generates ceramide at the PM. In our recent study, we have shown that inhibition of nSMase2 via either a highly potent and selective inhibitor, phenyl(R)‚Äê(1‚Äê(3‚Äê(3,4‚Äêdimethoxyphenyl)‚Äê2,6‚Äêdimethylimidazo[1,2‚Äêb] pyridazin‚Äê8‚Äêyl)pyrrolidin‚Äê3‚Äêyl)carbamate (PDDC), or siRNA knockdown disrupts HIV-1 Gag and GagPol polyprotein processing, thereby inhibiting maturation and infectivity of viral particles (Waheed et al., PNAS 2023). However, the precise mechanism by which nSMase2 inhibition affects viral protein processing and maturation remains unknown. To elucidate the mechanism of action of PDDC we passaged HIV-1 in immortalized T cell lines under suboptimal concentrations of PDDC. We were able to select for and identify mutations in the HIV-1 structural proteins and enzymes that confer partial resistance to the nSMase2 inhibitor. This PDDC resistance was confirmed in single-cycle HIV-1 infectivity and viral replication assays. By elucidating the mechanism of viral escape, we will shed light on the role of nSMase2 in HIV-1 maturation.
Scientific Focus Area: Virology
This page was last updated on Monday, September 25, 2023