P311 Influences Macrophage Polarization

Abstract

Obesity is a pandemic disease that has become a serious concern worldwide. In United States, recently self-reported obesity rates of adults were escalated to 40%. In the early phase of obesity, excessive macrophage infiltration and disequilibrium of macrophage phenotypes (M1 vs. M2 or vice versa) play a critical role in the microenvironment of adipose tissue. It often leads to chronic inflammation and is a major cause for metabolic disorders including insulin resistance, type-2 diabetes, and cardiovascular diseases. P311 is an intrinsically disordered protein, contributes to adipogenesis as transcription regulator through activation of PPARγ2, master regulator of adipogenesis. However, the P311 role on the macrophage polarization was not known. Here we studied the macrophage polarization in presence of P311 using Raw 264.7 cells. Raw cells were treated with either interleukin-4 (IL4) or lipopolysaccharide (LPS) for macrophage polarization towards M2 and M1 phenotype respectively in presence and absence of P311 overexpression. Macrophage phenotypic switch was assessed using CD206 (M2 marker) and CD86 (M1 marker) expression. The dose and time dependent effects of IL4 and LPS on the expression of P311 and macrophage markers was also studied. A significant increase in endogenous P311 expression observed with IL4 treatment whereas LPS treatment showed the opposite effect. Our findings showed that the P311 overexpression promotes anti-inflammatory macrophage phenotype (M2) as indicated by the significant increase in mRNA and protein expression of CD206 when compared to empty vector (EV, pCMV) transfected control group. Further, P311 overexpression in LPS treated RAW cells significantly increased the expression of CD206, on contrary to the classical M1 polarization of LPS, compared to EV transfected cells. In addition, P311 suppressed the expression of CD86 there by facilitating macrophage switch towards anti-inflammatory phenotype in presence of LPS treatment. IL4 treatment alone increased macrophage activation towards M2 phenotype however IL4 treated P311 overexpressed cells showed further increase in CD206 expression compared to EV transfected cells. Our studies indicate that the P311 expression plays an important role in promoting macrophage polarization toward M2 phenotype. This study was supported by research funding to KB, from NIH/NIGMS #SC1GM141937. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.