Murine Norovirus-3 (MNV-3) Infection Inhibits Atherosclerosis Development by Suppressing the CD36, CD88, and CD11b Expression in Oxidized Low-Density Lipoprotein (oxLDL)- Treated RAW264.7 Cells.

Introduction: Atherosclerosis is a chronic inflammatory condition characterized by arterial foam cell accumulation. In mice, MNV-infected macrophages develop atherosclerotic lesions. Due to MNV-3's affinity for macrophages expressing CD36, CD88, and CD11b, we examined its influence on these markers. Materials and methods: Recombinant MNV-3 was recovered using a DNA-based recovery system as described previously. The third passage of MNV-3 was used to infect RAW 264.7 cells at MOI of 0.5 followed by treatment with 80µg/ml of oxLDL and samples were collected 24 hours post-treatment for various assays. Verification of MNV-3 infection was achieved through PCR, TCID50, and Western blotting analyses. The ORO staining and TCE assays were used to assess lipid droplets and total cholesterol content. The FACS and qRT-PCR assays were carried out to measure CD36, CD88, and CD11b cell surface proteins and mRNA expression levels. ELISA analysis quantified the IL-ß, TNF-a, TGF-ß, and IL-6 secretion levels. Results: MNV-3 infection in RAW 264.7 cells was confirmed by PCR with a 342bp amplicon targeting the viral subgenomic region. OxLDL inhibited MNV-3 replication in RAW 264.7 cells. Combining MNV-3 with oxLDL significantly decreases RAW 264.7 CD36, CD88, and CD11b surface protein expression. This treatment regime also significantly reduced the CD36 and CD88 transcript levels. MNV-3 with oxLDL significantly reduced IL-1ß, IL-6, and TNF-a secretion whilst TGF-ß was significantly increased. Conclusion: Combining MNV-3 with oxLDL reduced cholesterol and lipid droplets by decreasing CD36, CD88, and CD11b, reducing L-1ß, IL-6, and TNF-a secretions, and enhancing TGF-ß secretion. The study suggests that MNV-3 infection exhibits anti-atherogenic effects, potentially offering biomedical implications. [ABSTRACT FROM AUTHOR]