Growing evidence suggests close associations between periodontitis and atherosclerosis.To further understand the pathological relationships of these associations,we developed periodontitis with ligature placement arou...Growing evidence suggests close associations between periodontitis and atherosclerosis.To further understand the pathological relationships of these associations,we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g.LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals.The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis,systemic inflammation,and atherosclerosis.Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas,but mice receiving ligature or ligature/P.g.LPS showed severe periodontitis,systemic inflammation,and aortic plaque formation.The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers.The severity of periodontitis was slightly higher in mice receiving ligature/P.g.LPS than ligature alone,and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g.LPS.These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis.In vitro,P.g.LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells.Moreover,secretory proteins,such as TNF-α,from macrophages induced endothelial–mesenchymal transitions of the endothelial cells.Taken together,systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via,in part,causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice.展开更多
Osteoporosis is a highly prevalent public health burden associated with an increased risk of bone fracture, particularly in aging women. Estrogen, an important medicinal component for the preventative and therapeutic ...Osteoporosis is a highly prevalent public health burden associated with an increased risk of bone fracture, particularly in aging women. Estrogen, an important medicinal component for the preventative and therapeutic treatment of postmenopausal osteoporosis, induces osteogenesis by activating the estrogen receptor signaling pathway and upregulating the expression of osteogenic genes, such as bone morphogenetic proteins(BMPs). The epigenetic regulation of estrogen-mediated osteogenesis,however, is still unclear. In this report, we found that estrogen significantly induced the expression of lysine-specific demethylase 6B(KDM6B) and that KDM6B depletion by shRNAs led to a significant reduction in the osteogenic potential of DMSCs.Mechanistically, upon estrogen stimulation, estrogen receptor-α(ERα) was recruited to the KDM6B promoter, directly enhancing KDM6B expression. Subsequently, KDM6B was recruited to the BMP2 and HOXC6 promoters, resulting in the removal of H3K27me3 marks and activating the transcription of BMP2 and HOXC6, the master genes of osteogenic differentiation. Furthermore, we found that estrogen enhanced DMSC osteogenesis during calvarial bone regeneration and that estrogen’s pro-osteogenic effect was dependent on KDM6B in vivo. Taken together, our results demonstrate the vital role of the ERα/KDM6B regulatory axis in the epigenetic regulation of the estrogen-dependent osteogenic response.展开更多
基金supported, in part, by the research funds awarded from the UCLA Chancellor’s Office (N.-H.P.)NIH/NIDCR DE 023348 (R.H.K. and N.-H.P.)NIH/NHLBI HL30568 (K.I.B.)
文摘Growing evidence suggests close associations between periodontitis and atherosclerosis.To further understand the pathological relationships of these associations,we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g.LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals.The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis,systemic inflammation,and atherosclerosis.Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas,but mice receiving ligature or ligature/P.g.LPS showed severe periodontitis,systemic inflammation,and aortic plaque formation.The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers.The severity of periodontitis was slightly higher in mice receiving ligature/P.g.LPS than ligature alone,and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g.LPS.These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis.In vitro,P.g.LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells.Moreover,secretory proteins,such as TNF-α,from macrophages induced endothelial–mesenchymal transitions of the endothelial cells.Taken together,systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via,in part,causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice.
基金supported by NIH/NIDCR grants K08DE024603, R01DE16513, and R01DE024828
文摘Osteoporosis is a highly prevalent public health burden associated with an increased risk of bone fracture, particularly in aging women. Estrogen, an important medicinal component for the preventative and therapeutic treatment of postmenopausal osteoporosis, induces osteogenesis by activating the estrogen receptor signaling pathway and upregulating the expression of osteogenic genes, such as bone morphogenetic proteins(BMPs). The epigenetic regulation of estrogen-mediated osteogenesis,however, is still unclear. In this report, we found that estrogen significantly induced the expression of lysine-specific demethylase 6B(KDM6B) and that KDM6B depletion by shRNAs led to a significant reduction in the osteogenic potential of DMSCs.Mechanistically, upon estrogen stimulation, estrogen receptor-α(ERα) was recruited to the KDM6B promoter, directly enhancing KDM6B expression. Subsequently, KDM6B was recruited to the BMP2 and HOXC6 promoters, resulting in the removal of H3K27me3 marks and activating the transcription of BMP2 and HOXC6, the master genes of osteogenic differentiation. Furthermore, we found that estrogen enhanced DMSC osteogenesis during calvarial bone regeneration and that estrogen’s pro-osteogenic effect was dependent on KDM6B in vivo. Taken together, our results demonstrate the vital role of the ERα/KDM6B regulatory axis in the epigenetic regulation of the estrogen-dependent osteogenic response.
