Qing Zhao1, Xin Wang1, Qiaosheng Hu1, Ridong Zhang2, Yong Yin3. 1. Department of Endocrinology, Lianshui County People's Hospital, Huai'an, China. 2. Department of endocrinology, Huai'an First People's Hospital of Nanjing Media University, Huai'an, China. 3. Department of Endocrinology, Changzhou Wujin People's Hospital, Changzhou, China.
Abstract
OBJECTIVES: Lipopolysaccharide (LPS) contributed to the development and progression of type 2 diabetes mellitus (T2D), while TLR4 is reported to mediate the LPS-induced inflammation in macrophages. However, the potential molecular mechanisms for TLR4-mediated macrophages activation in T2D have not yet to be fully clarified. METHODS: Type 2 diabetes models in C57BL/6J mice were generated by a combination administration of streptozotocin (STZ) and a high-fat diet (HFD). Cell proportions of M1 and M2 macrophages were analyzed using flow cytometry. Expression profiles of miR-448 and TLR 4 were determined by qRT-PCR and Western blot. KEY FINDINGS: LPS/IFN-γ significantly induced M1 polarization in macrophages characterized by the increased levels of TNF-α, IL-6, IL-12, iNOS and decreased levels of TNF-β, CCL-22, IL-10 and Arg-1, with a higher expression of toll-like receptor 4 (TLR4) in vitro. Consistently, T2D mice-derived macrophages had a significantly elevated expression of TLR4 mRNA and decreased expression of miR-448. We further confirmed that miR-448 could inhibit TLR4 expression by targeting the 3'-UTR of TLR4, rescuing the LPS/IFN-γ-induced M1 macrophage polarization. CONCLUSIONS: Taken together, our results indicated that decreased miR-448 in diabetic macrophages may contribute to LPS-induced M1 polarization by targeting TLR4, thereby modulating T2D development.
OBJECTIVES:Lipopolysaccharide (LPS) contributed to the development and progression of type 2 diabetes mellitus (T2D), while TLR4 is reported to mediate the LPS-induced inflammation in macrophages. However, the potential molecular mechanisms for TLR4-mediated macrophages activation in T2D have not yet to be fully clarified. METHODS: Type 2 diabetes models in C57BL/6J mice were generated by a combination administration of streptozotocin (STZ) and a high-fat diet (HFD). Cell proportions of M1 and M2 macrophages were analyzed using flow cytometry. Expression profiles of miR-448 and TLR 4 were determined by qRT-PCR and Western blot. KEY FINDINGS:LPS/IFN-γ significantly induced M1 polarization in macrophages characterized by the increased levels of TNF-α, IL-6, IL-12, iNOS and decreased levels of TNF-β, CCL-22, IL-10 and Arg-1, with a higher expression of toll-like receptor 4 (TLR4) in vitro. Consistently, T2D mice-derived macrophages had a significantly elevated expression of TLR4 mRNA and decreased expression of miR-448. We further confirmed that miR-448 could inhibit TLR4 expression by targeting the 3'-UTR of TLR4, rescuing the LPS/IFN-γ-induced M1 macrophage polarization. CONCLUSIONS: Taken together, our results indicated that decreased miR-448 in diabetic macrophages may contribute to LPS-induced M1 polarization by targeting TLR4, thereby modulating T2D development.
Authors: Denis Ohlstrom; Laura Hernandez-Lagunas; Anastacia M Garcia; Ayed Allawzi; Anis Karimpour-Fard; Carmen C Sucharov; Eva Nozik-Grayck Journal: Physiol Genomics Date: 2020-05-18 Impact factor: 3.107