Epigallocatechin-3-gallate(EGCG), a major polyphenolic compound in green tea, exhibits antiviral activity against multiple viruses, including hepatitis B virus(HBV). However, its role in HBV replication and the underl...Epigallocatechin-3-gallate(EGCG), a major polyphenolic compound in green tea, exhibits antiviral activity against multiple viruses, including hepatitis B virus(HBV). However, its role in HBV replication and the underlying mechanisms remain incompletely understood. In this study, we investigated the effects of EGCG on HBV replication and its modulation of autophagy using two established HBV cell models. Our results show that EGCG significantly reduces secreted levels of hepatitis B surface antigen(HBsAg) and HBV deoxyribonucleic acid(DNA), as well as intracellular HBV DNA replicative intermediates, encapsidated pregenomic ribonucleic acid(pgRNA), and core protein(HBc), without affecting total HBV messenger RNAs(mRNAs) or pgRNA levels. EGCG enhances autophagic flux, evidenced by increased autophagosome formation and accelerated turnover of the selective autophagy receptor p62 and LC3-Ⅱ. This enhanced autophagy promotes HBc degradation. Pharmacological inhibition of autophagy with 3-methyladenine(3-MA), chloroquine(CQ), or bafilomycin A1(BafA1) abolished the suppressive effect of EGCG on HBV. Notably, treatment with CQ or BafA1 together with EGCG markedly increased HBV production by blocking autophagic degradation and inducing accumulation of autophagosomes—effects similar to those induced by the autophagy activator rapamycin, which facilitates HBV replication. Mechanistically, EGCG activates the adenosine 5'-monophosphate-activated protein kinase(AMPK)/transcription factor EB(TFEB)signaling axis, leading to enhanced lysosomal biogenesis and ATP production, thereby promoting autophagic clearance. Pharmacological or genetic inhibition of AMPK attenuated TFEB transcriptional activity, suppressed lysosomal biogenesis and ATP generation, impaired autophagic degradation, increased HBc levels, and ultimately enhanced HBV replication. Conversely, pharmacological activation of AMPK produced opposing effects. These findings reveal a novel mechanism by which EGCG inhibits HBV: EGCG promotes autophagic degradation of the viral core protein via activation of the AMPK/TFEB signaling pathway.展开更多
The effectiveness of cranial suture expansion therapy hinges on the timely and adequate regeneration of bone tissue in response to mechanical stimuli.To optimize clinical outcomes and prevent post-expansion relapse,we...The effectiveness of cranial suture expansion therapy hinges on the timely and adequate regeneration of bone tissue in response to mechanical stimuli.To optimize clinical outcomes and prevent post-expansion relapse,we delved into the underlying mechanisms governing bone remodeling during the processes of suture expansion and relapse.Our findings revealed that in vitro stretching bolstered mesenchymal stem cells'antioxidative and osteogenic capacity by orchestrating mitochondrial activities,which governed by force-induced endoplasmic reticulum(ER)stress.Nonetheless,this signal transduction occurred through the activation of protein kinase R-like ER kinase(PERK)at the ER-mitochondria interface,rather than ER-mitochondria calcium flow as previously reported.Subsequently,PERK activation triggered TFEB translocation to the nucleus,thus regulating mitochondrial dynamics transcriptionally.Assessment of the mitochondrial pool during expansion and relapse unveiled a sequential,two-phase regulation governed by the ER stress/p-PERK/TFEB signaling cascade.Initially,PERK activation facilitated TFEB nuclear localization,stimulating mitochondrial biogenesis through PGC1-α,thereby addressing energy demands during the initial phase.Subsequently,TFEB shifted focus towards ensuring adequate mitophagy for mitochondrial quality maintenance during the remodeling process.Premature withdrawal of expanding force disrupted this sequential regulation,leading to compromised mitophagy and the accumulation of dysfunctional mitochondria,culminating in suboptimal bone regeneration and relapse.Notably,pharmacological activation of mitophagy effectively mitigated relapse and attenuated bone loss,while its inhibition impeded anticipated bone growth in remodeling progress.Conclusively,we elucidated the ER stress/p-PERK/TFEB signaling orchestrated sequential mitochondria biogenesis and mitophagy under mechanical stretch,thus ensuring antioxidative capacity and osteogenic potential of cranial suture tissues.展开更多
基金江西省自然科学基金项目(编号:20202BAB206075)江西省教育厅科技项目(编号:GJJ201202)江西中医药大学中西医结合一级学科平台(Discipline of Chinese and Western Integrative Medicine,Jiangxi University of Chinese Medicine)。
基金supported by the National Natural Science Foundation of China (No. 81600470)the Natural Science Foundation of Shandong Province of China (Nos. ZR2022MC053 and ZR2023MH122)。
文摘Epigallocatechin-3-gallate(EGCG), a major polyphenolic compound in green tea, exhibits antiviral activity against multiple viruses, including hepatitis B virus(HBV). However, its role in HBV replication and the underlying mechanisms remain incompletely understood. In this study, we investigated the effects of EGCG on HBV replication and its modulation of autophagy using two established HBV cell models. Our results show that EGCG significantly reduces secreted levels of hepatitis B surface antigen(HBsAg) and HBV deoxyribonucleic acid(DNA), as well as intracellular HBV DNA replicative intermediates, encapsidated pregenomic ribonucleic acid(pgRNA), and core protein(HBc), without affecting total HBV messenger RNAs(mRNAs) or pgRNA levels. EGCG enhances autophagic flux, evidenced by increased autophagosome formation and accelerated turnover of the selective autophagy receptor p62 and LC3-Ⅱ. This enhanced autophagy promotes HBc degradation. Pharmacological inhibition of autophagy with 3-methyladenine(3-MA), chloroquine(CQ), or bafilomycin A1(BafA1) abolished the suppressive effect of EGCG on HBV. Notably, treatment with CQ or BafA1 together with EGCG markedly increased HBV production by blocking autophagic degradation and inducing accumulation of autophagosomes—effects similar to those induced by the autophagy activator rapamycin, which facilitates HBV replication. Mechanistically, EGCG activates the adenosine 5'-monophosphate-activated protein kinase(AMPK)/transcription factor EB(TFEB)signaling axis, leading to enhanced lysosomal biogenesis and ATP production, thereby promoting autophagic clearance. Pharmacological or genetic inhibition of AMPK attenuated TFEB transcriptional activity, suppressed lysosomal biogenesis and ATP generation, impaired autophagic degradation, increased HBc levels, and ultimately enhanced HBV replication. Conversely, pharmacological activation of AMPK produced opposing effects. These findings reveal a novel mechanism by which EGCG inhibits HBV: EGCG promotes autophagic degradation of the viral core protein via activation of the AMPK/TFEB signaling pathway.
基金supported by National Natural Science Foundation of China(No.82370988,32271416,81870743,82170934)Sichuan Province Science and Technology Support Program(2024YFHZ0043)。
文摘The effectiveness of cranial suture expansion therapy hinges on the timely and adequate regeneration of bone tissue in response to mechanical stimuli.To optimize clinical outcomes and prevent post-expansion relapse,we delved into the underlying mechanisms governing bone remodeling during the processes of suture expansion and relapse.Our findings revealed that in vitro stretching bolstered mesenchymal stem cells'antioxidative and osteogenic capacity by orchestrating mitochondrial activities,which governed by force-induced endoplasmic reticulum(ER)stress.Nonetheless,this signal transduction occurred through the activation of protein kinase R-like ER kinase(PERK)at the ER-mitochondria interface,rather than ER-mitochondria calcium flow as previously reported.Subsequently,PERK activation triggered TFEB translocation to the nucleus,thus regulating mitochondrial dynamics transcriptionally.Assessment of the mitochondrial pool during expansion and relapse unveiled a sequential,two-phase regulation governed by the ER stress/p-PERK/TFEB signaling cascade.Initially,PERK activation facilitated TFEB nuclear localization,stimulating mitochondrial biogenesis through PGC1-α,thereby addressing energy demands during the initial phase.Subsequently,TFEB shifted focus towards ensuring adequate mitophagy for mitochondrial quality maintenance during the remodeling process.Premature withdrawal of expanding force disrupted this sequential regulation,leading to compromised mitophagy and the accumulation of dysfunctional mitochondria,culminating in suboptimal bone regeneration and relapse.Notably,pharmacological activation of mitophagy effectively mitigated relapse and attenuated bone loss,while its inhibition impeded anticipated bone growth in remodeling progress.Conclusively,we elucidated the ER stress/p-PERK/TFEB signaling orchestrated sequential mitochondria biogenesis and mitophagy under mechanical stretch,thus ensuring antioxidative capacity and osteogenic potential of cranial suture tissues.
