Background Lactate is a classical byproduct of glucose metabolism,and the main lactate production pathway depends on glycolysis.Lactate stabilized HIF1αby inhibiting PHD activity,leading to hypoxic stress response an...Background Lactate is a classical byproduct of glucose metabolism,and the main lactate production pathway depends on glycolysis.Lactate stabilized HIF1αby inhibiting PHD activity,leading to hypoxic stress response and exacerbating glycolysis in multiple tissues.However,the redox induction mechanism of lactate in mammary gland has not been understood yet.Herein,we describe a lactate-responsive HIF1α/circadian control mechanism in oxidative stress in the mammary glands of dairy cows.Results The in vivo study showed that dairy cows with high lactate concentrations are associated with reduced milk yield and more ROS accumulation in mammary gland.Western blot results in MAC-T cells showed positive correlation between lactate concentrations,expression of HIF1αand oxidative stress indicators,but not circadian core components.To test how lactate-mediated HIF1αdysfunction leads to cell protection process,we investigated altered expression of circadian core related genes following HIF1αstabilization.We found that stabilized HIF1αby lactate inhibited stimulated expression of circadian core components due to the similarity of HRE and E-box transcription elements.Furthermore,we found that lactate treatment strengthened the binding of HIF1αwith BMAL1,HMOX1 and FOXO3 in MAC-T cells.Moreover,HIF1αknockdown altered expression of circadian rhythm related genes and reduced oxidative stress state.Conclusion In summary,our study highlights the central role of competitive transcriptional element occupancy in lactate-mediated oxidative stress of mammary gland,which is caused by HIF1αstabilization and circadian rhythm dysfunction.Our findings introduce a novel nutritional strategy with potential applications in dairy farming for optimizing milk production and maintaining mammary gland health.展开更多
Background Hypoxic stimuli induce follicular atresia by regulating granulosa cell(GC)apoptosis.Notably,mature follicles can still develop and ovulate under hypoxic conditions,highlighting the importance of the hypoxic...Background Hypoxic stimuli induce follicular atresia by regulating granulosa cell(GC)apoptosis.Notably,mature follicles can still develop and ovulate under hypoxic conditions,highlighting the importance of the hypoxic adaptation in ovarian follicular selection.To date,the role and mechanism of hypoxia-inducible factor 1 subunit alpha(HIF1A)-mediated hypoxic responses in follicular atresia are unclear.This study aimed to investigate whether and how HIF1A regulates follicular atresia via the modulation of O-linked N-acetylglucosamine(O-GlcNAc)protein modification(O-GlcNAcylation).Results Our findings revealed that HIF1A was highly expressed in pig ovaries.Compared with that in healthy follicles,its expression was significantly downregulated in atretic follicles.Under hypoxic conditions,pharmacological inhibition or siRNA-mediated knockdown of HIF1A increased porcine GC apoptosis.Mechanistically,HIF1A knockdown Suppressed O-GlcNAc transferase degradation,leading to increased global O-GlcNAcylation.Using 4D labelfree quantitative proteomics,we identified 53 O-GlcNAcylated proteins.Importantly,O-GlcNAcylation stabilized vascular endothelial zinc finger 1(VEZF1),and HIF1A knockdown upregulated VEZF1 protein levels by promoting O-GlcNAcylation.The HIF1A-VEZF1 axis modulates forkhead box O1(FOXO1)expression by regulating endothelin-1.As a transcription factor,FOXO1 directly binds to the Bcl-2 associated X(BAX)promoter,activating its transcription and ultimately inducing porcine GC apoptosis and follicular atresia.Conclusion Overall,our study elucidates a novel molecular mechanism by which HIF1A deficiency modulates follicular atresia through O-GlcNAcylation-mediated VEZF1 expression.These results not only clarify the molecular mechanism of ovarian follicular development under hypoxic conditions but also offer potential targets for improving follicular selection efficiency in pig breeding.展开更多
Osteocytes are the main cells in mineralized bone tissue.Elevated osteocyte apoptosis has been observed in lytic bone lesions of patients with multiple myeloma.However,their precise contribution to bone metastasis rem...Osteocytes are the main cells in mineralized bone tissue.Elevated osteocyte apoptosis has been observed in lytic bone lesions of patients with multiple myeloma.However,their precise contribution to bone metastasis remains unclear.Here,we investigated the pathogenic mechanisms driving melanoma-induced osteocyte death.Both in vivo models and in vitro assays were combined with untargeted RNA sequencing approaches to explore the pathways governing melanoma-induced osteocyte death.We could show that ferroptosis is the primary mechanism behind osteocyte death in the context of melanoma bone metastasis.HMOX1 was identified as a crucial regulatory factor in this process,directly involved in inducing ferroptosis and affecting osteocyte viability.We uncover a non-canonical pathway that involves excessive autophagy-mediated ferritin degradation,highlighting the complex relationship between autophagy and ferroptosis in melanoma-induced osteocyte death.In addition,HIF1αpathway was shown as an upstream regulator,providing a potential target for modulating HMOX1 expression and influencing autophagy-dependent ferroptosis.In conclusion,our study provides insight into the pathogenic mechanisms of osteocyte death induced by melanoma bone metastasis,with a specific focus on ferroptosis and its regulation.This would enhance our comprehension of melanoma-induced osteocyte death.展开更多
基金supported by National Nature Science Foundation of China(32102552 and 32172741).
文摘Background Lactate is a classical byproduct of glucose metabolism,and the main lactate production pathway depends on glycolysis.Lactate stabilized HIF1αby inhibiting PHD activity,leading to hypoxic stress response and exacerbating glycolysis in multiple tissues.However,the redox induction mechanism of lactate in mammary gland has not been understood yet.Herein,we describe a lactate-responsive HIF1α/circadian control mechanism in oxidative stress in the mammary glands of dairy cows.Results The in vivo study showed that dairy cows with high lactate concentrations are associated with reduced milk yield and more ROS accumulation in mammary gland.Western blot results in MAC-T cells showed positive correlation between lactate concentrations,expression of HIF1αand oxidative stress indicators,but not circadian core components.To test how lactate-mediated HIF1αdysfunction leads to cell protection process,we investigated altered expression of circadian core related genes following HIF1αstabilization.We found that stabilized HIF1αby lactate inhibited stimulated expression of circadian core components due to the similarity of HRE and E-box transcription elements.Furthermore,we found that lactate treatment strengthened the binding of HIF1αwith BMAL1,HMOX1 and FOXO3 in MAC-T cells.Moreover,HIF1αknockdown altered expression of circadian rhythm related genes and reduced oxidative stress state.Conclusion In summary,our study highlights the central role of competitive transcriptional element occupancy in lactate-mediated oxidative stress of mammary gland,which is caused by HIF1αstabilization and circadian rhythm dysfunction.Our findings introduce a novel nutritional strategy with potential applications in dairy farming for optimizing milk production and maintaining mammary gland health.
基金supported by the National Natural Science Foundation of China(32402710)National Postdoctoral Researchers Funding Program(GZC20232209)+1 种基金Higher Education Institutions Basic Science(Natural Science)Research General Program of Jiangsu Province(24KJB230005)Priority Academic Program Development of Jiangsu Higher Education Institution.
文摘Background Hypoxic stimuli induce follicular atresia by regulating granulosa cell(GC)apoptosis.Notably,mature follicles can still develop and ovulate under hypoxic conditions,highlighting the importance of the hypoxic adaptation in ovarian follicular selection.To date,the role and mechanism of hypoxia-inducible factor 1 subunit alpha(HIF1A)-mediated hypoxic responses in follicular atresia are unclear.This study aimed to investigate whether and how HIF1A regulates follicular atresia via the modulation of O-linked N-acetylglucosamine(O-GlcNAc)protein modification(O-GlcNAcylation).Results Our findings revealed that HIF1A was highly expressed in pig ovaries.Compared with that in healthy follicles,its expression was significantly downregulated in atretic follicles.Under hypoxic conditions,pharmacological inhibition or siRNA-mediated knockdown of HIF1A increased porcine GC apoptosis.Mechanistically,HIF1A knockdown Suppressed O-GlcNAc transferase degradation,leading to increased global O-GlcNAcylation.Using 4D labelfree quantitative proteomics,we identified 53 O-GlcNAcylated proteins.Importantly,O-GlcNAcylation stabilized vascular endothelial zinc finger 1(VEZF1),and HIF1A knockdown upregulated VEZF1 protein levels by promoting O-GlcNAcylation.The HIF1A-VEZF1 axis modulates forkhead box O1(FOXO1)expression by regulating endothelin-1.As a transcription factor,FOXO1 directly binds to the Bcl-2 associated X(BAX)promoter,activating its transcription and ultimately inducing porcine GC apoptosis and follicular atresia.Conclusion Overall,our study elucidates a novel molecular mechanism by which HIF1A deficiency modulates follicular atresia through O-GlcNAcylation-mediated VEZF1 expression.These results not only clarify the molecular mechanism of ovarian follicular development under hypoxic conditions but also offer potential targets for improving follicular selection efficiency in pig breeding.
基金funding from the European Research Council(ERC)under the european union Horizon 2020 research and innovation program(grant agreement ERC co-LS4 ODE(AB)and ERC Synergy Grant 4D Nanoscope(GS))Deutsche Forschungsgemeinschaft DFG-Project number 501752319-TRR369-DIONE-Project No A02 and B05,FOR 2886(TP02),CRC1181(TPA01)DFG funding(450993414)Thunder Imager and the Leibniz Award(GS)。
文摘Osteocytes are the main cells in mineralized bone tissue.Elevated osteocyte apoptosis has been observed in lytic bone lesions of patients with multiple myeloma.However,their precise contribution to bone metastasis remains unclear.Here,we investigated the pathogenic mechanisms driving melanoma-induced osteocyte death.Both in vivo models and in vitro assays were combined with untargeted RNA sequencing approaches to explore the pathways governing melanoma-induced osteocyte death.We could show that ferroptosis is the primary mechanism behind osteocyte death in the context of melanoma bone metastasis.HMOX1 was identified as a crucial regulatory factor in this process,directly involved in inducing ferroptosis and affecting osteocyte viability.We uncover a non-canonical pathway that involves excessive autophagy-mediated ferritin degradation,highlighting the complex relationship between autophagy and ferroptosis in melanoma-induced osteocyte death.In addition,HIF1αpathway was shown as an upstream regulator,providing a potential target for modulating HMOX1 expression and influencing autophagy-dependent ferroptosis.In conclusion,our study provides insight into the pathogenic mechanisms of osteocyte death induced by melanoma bone metastasis,with a specific focus on ferroptosis and its regulation.This would enhance our comprehension of melanoma-induced osteocyte death.
