SAMHD1 enhances HIV-1-induced glycolysis in monocytic cells through hexokinase 2 upregulation

Abstract

SAMHD1 is a mitochondria-associated cellular protein that restricts HIV-1 replication by depleting intracellular dNTP pools in non-dividing immune cells, such as macrophages, dendritic cells, and resting CD4+ T cells; however, its role in host metabolism remains unclear. Building on our previous finding that SAMHD1 promotes mitochondrial membrane damage in HIV-1-infected monocytic cells, here we identify a new function for SAMHD1 in enhancing HIV-1-induced glycolysis through upregulation of hexokinase 2 (HK2). In monocytic THP-1 cells, but not differentiated macrophage-like cells, SAMHD1 amplifies HIV-1-triggered glucose uptake and basal glycolysis. Mechanistically, SAMHD1 increases HK2 expression and promotes its cytosolic accumulation, leading to elevated reactive oxygen species (ROS) production. This SAMHD1-dependent metabolic rewiring links antiviral restriction to glycolytic control and cellular stress responses. Our findings reveal a cell state-specific role for SAMHD1 in regulating glycolysis during HIV-1 infection, identify HK2 as a key effector, and uncover an unanticipated layer of host-virus interaction in monocytic cells. IMPORTANCESAMHD1 is best known as a restriction factor that inhibits HIV-1 replication mainly through its dNTPase activity. However, emerging evidence suggests that SAMHD1 also regulates mitochondrial homeostasis and cellular metabolism. We previously demonstrated that SAMHD1 promotes HIV-1-induced apoptosis in monocytic cells through a mitochondrial pathway, implicating SAMHD1 in the control of mitochondrial function during infection. Because mitochondria are central regulators of cellular energy metabolism, we investigated whether SAMHD1 influences glycolytic reprogramming in HIV-1-infected monocytic cells. Our results show that SAMHD1 enhances glucose uptake, glycolysis, HK2 expression, and ROS production during HIV-1 infection. These findings reveal a previously unrecognized role for SAMHD1 in coordinating metabolic and oxidative stress responses to HIV-1 infection and provide new mechanistic insight into the interplay between antiviral factors, cellular metabolism, and HIV-1 pathogenesis. Understanding how SAMHD1 regulates glucose metabolism may uncover novel links between innate immune defenses and metabolic disease.