Mice harboring a human Mediterranean G6PD gene variant causing G6PD deficiency have decreased B1b cells and atheroprotective IgM, and increased atherosclerosis.

Abstract

Epidemiological studies suggest a role of glucose 6-phosphate dehydrogenase deficiency (G6PDd) in exacerbated atherosclerosis. To date, no studies have established a causal relationship between the two. We herein report the first direct evidence of G6PDd causing atherosclerosis and deficits in B cells. Mice harboring the human Mediterranean G6PDd variant (hG6PDMed-) or the nondeficient human G6PD allele (hG6PDND) were rendered hyperlipemic via PCSK9 AAV and 12 weeks of high fat diet (HFD). Sudan-IV en face staining revealed increased atherosclerosis in the G6PDd mice when normalized to non-HDL cholesterol (hG6PDND n=9, hG6PDMed- n=8, P=0.0339). Next, flow cytometry was used to identify alterations in immune cells involved in atherosclerosis and revealed reduced atheroprotective B1b cells (CD19+B220-IgM+CD5-) in the peritoneal cavity and spleen (hG6PDND n=9, hG6PDMed- n=8, P=0.0111 & P=0.0207). B1b cells secrete atheroprotective IgM to oxidation-specific epitopes (IgMOSE), and thus ELISA was used to measure IgMOSE levels. Despite normal total IgM levels compared to non-G6PDd mice, G6PDd mice had reduced IgMOSE to CuOx-LDL and PC-BSA when normalized to total IgM at baseline (hG6PDND n=8, hG6PDMed- n=7, P=0.0289 & P=0.0022) and at 2 weeks of HFD (hG6PDND n=9, hG6PDMed- n=6, P=0.0016 & P=0.0028). Together, these data demonstrate that G6PDd worsens atherosclerosis and suggest that this effect may be partly mediated by associated deficits in B1b cells and IgMOSE.