Viperin Regulates Cellular Lipid Metabolism during Human Cytomegalovirus Infection
Figure 2
Viperin expression induces HCMV-induced lipogenesis.
HFtelo cells stably expressing no shRNA, control luciferase (Luc) shRNA or viperin shRNAs were infected with HCMV at an moi of 2 for the indicated days. (A) Lipogenic enzyme mRNA levels. Total RNA was isolated, and the mRNA levels were measured by quantitative RT-PCR and normalized to β actin mRNA. Data are presented as means ± SEM of triplicate samples and are representative of three individual experiments. ACL, ATP-citrate lyase; ACC2, acetyl-coenzyme A (CoA) carboxylase 2; FAS, fatty acid synthase; DGAT1 and DGAT2, diacylglycerol acyltransferases 1 and 2. (B) Total lipid synthesis. The infected cells were labeled with [14C]-acetate for 3 hr. Total lipids from 1×105 cells were extracted and [14C] incorporation assessed. Data are presented as mean ± SEM of triplicate samples and are representative of two individual experiments. *, P<0.0001. (C) Cells were stained with antibodies specific to adipose differentiation-related protein (ADRP), a marker for lipid droplets (LDs), and gB, an HCMV glycoprotein. The filled arrows indicate the accumulated LDs, and the open arrows indicate barely detectable LDs in HCMV-infected viperin knockdown cells. Scale bar, 20 µm. (D) Quantification of LDs. LD diameter: mean of 500 LDs ± SEM.; LD number: mean of 50 cells ± SEM *, P<0.0001.