Ning Wang1, Jian Gao1, Min Jia1, Xue Ma1, Zhanxiang Lei2, Fei Da1, Fei Yan3, Huinan Zhang1, Ying Zhou1, Mingkai Li1, Gonghao He4, Jingru Meng1, Xiaoxing Luo1. 1. Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China. 2. Clinical laboratory center, Hospital No. 159 of P.L.A, Zhumadian, China. 3. Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, Xi'an, China. 4. Department of Pharmacy, Kunming General Hospital of Chengdu Military Region, Kunming, China.
Abstract
BACKGROUND/AIMS: The synthesis and degradation processes involved in bone remodeling are critically regulated by osteoblasts and osteoclasts. The GLP-1 receptor agonist Exendin-4 is beneficial for osteoblast differentiation and increases the number of osteoblasts. METHODS: We constructed an ovariectomized model to evaluate the impact of Exendin-4 on bone formation in osteoporosis. A macrophage-depleted model was also created to investigate the effect of macrophages on bone formation. Thirty-two female WT C57BL/6 mice (aged 3 months) were randomly assigned to a normal control group and four ovariectomized (OVX) subgroups: OVX + vehicle group, OVX + Exendin-4 (4.2 µg/kg/day) group, OVX + chloride phosphate liposome group and OVX + chloride phosphate liposome + Exendin-4 group. RESULTS: In this study, we found that Exendin-4 not only increased the number of osteoblasts and decreased the number of osteoclasts, but also increased the number of bone marrow stromal cells (BMSCs) at the bone surface. Moreover, we found that OVX mice treated with Exendin-4 increased TGF-β1 levels at the bone surface compared with that in OVX mice. Besides, Exendin-4 promoted the polarization of bone marrow-derived macrophages into M2 subtype and increased TGF-β1 secretion by the M2 subtype. Finally, we found that Exendin-4 induced macrophage polarization via the cAMP-PKA-STAT3 signaling pathway. CONCLUSION: Exendin-4 promotes bone marrow-derived macrophage polarization to the M2 subtype and induces BMSC migration to the bone surface via PKA-STAT3 signaling.
BACKGROUND/AIMS: The synthesis and degradation processes involved in bone remodeling are critically regulated by osteoblasts and osteoclasts. The GLP-1 receptor agonist Exendin-4 is beneficial for osteoblast differentiation and increases the number of osteoblasts. METHODS: We constructed an ovariectomized model to evaluate the impact of Exendin-4 on bone formation in osteoporosis. A macrophage-depleted model was also created to investigate the effect of macrophages on bone formation. Thirty-two female WT C57BL/6 mice (aged 3 months) were randomly assigned to a normal control group and four ovariectomized (OVX) subgroups: OVX + vehicle group, OVX + Exendin-4 (4.2 µg/kg/day) group, OVX + chloride phosphate liposome group and OVX + chloride phosphate liposome + Exendin-4 group. RESULTS: In this study, we found that Exendin-4 not only increased the number of osteoblasts and decreased the number of osteoclasts, but also increased the number of bone marrow stromal cells (BMSCs) at the bone surface. Moreover, we found that OVX mice treated with Exendin-4 increased TGF-β1 levels at the bone surface compared with that in OVX mice. Besides, Exendin-4 promoted the polarization of bone marrow-derived macrophages into M2 subtype and increased TGF-β1 secretion by the M2 subtype. Finally, we found that Exendin-4 induced macrophage polarization via the cAMP-PKA-STAT3 signaling pathway. CONCLUSION: Exendin-4 promotes bone marrow-derived macrophage polarization to the M2 subtype and induces BMSC migration to the bone surface via PKA-STAT3 signaling.
Authors: Hong Lei; Mingyu He; Xiaoqi He; Guanghui Li; Yang Wang; Yuelin Gao; Gege Yan; Quan Wang; Tao Li; Guoxin Liu; Weijie Du; Ye Yuan; Lei Yang Journal: Am J Transl Res Date: 2021-05-15 Impact factor: 4.060