Mitochondrial calcium uniporter （MCU） is a conserved Ca2＋ transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress- induced cell death remains unclear. Here, we showed ...Mitochondrial calcium uniporter （MCU） is a conserved Ca2＋ transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress- induced cell death remains unclear. Here, we showed that ectopically expressed MCU is mitochondrial local- ized in both HeLa and primary cerebellar granule neu- rons （CGNs）. Knockdown of endogenous MCU decreases mitochondrial Ca2＋ uptake following his- tamine stimulation and attenuates cell death induced by oxidative stress in both HeLa cells and CGNs. We also found MCU interacts with VDACl and mediates VDAC1 overexpression-induced cell death in CGNs. This finding demonstrates that MCU-VDACl complex regulates mi- tochondrial Ca2＋ uptake and oxidative stress-induced apoptosis, which might represent therapeutic targets for oxidative stress related diseases.展开更多
Acetaminophen(APAP)overdose is a major cause of liver injury.Neural precursor cell expressed developmentally downregulated 4—1(NEDD4-1)is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerou...Acetaminophen(APAP)overdose is a major cause of liver injury.Neural precursor cell expressed developmentally downregulated 4—1(NEDD4-1)is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerous liver diseases;however,its role in APAP-induced liver injury(AILI)is unclear.Thus,this study aimed to investigate the role of NEDD4-1 in the pathogenesis of AILI.We found that NEDD4-1 was dramatically downregulated in response to APAP treatment in mouse livers and isolated mouse hepatocytes.Hepatocyte-specific NEDD4-1 knockout exacerbated APAP-induced mitochondrial damage and the resultant hepatocyte necrosis and liver injury,while hepatocyte-specific NEDD4-1 overexpression mitigated these pathological events both in vivo and in vitro.Additionally,hepatocyte NEDD4-1 deficiency led to marked accumulation of voltage-dependent anion channel 1(VDAC1)and increased VDAC1 oligomerization.Furthermore,VDAC1 knockdown alleviated AILI and weakened the exacerbation of AILI caused by hepatocyte NEDD4-1 deficiency.Mechanistically,NEDD4-1 was found to interact with the PPTY motif of VDAC1 through its WW domain and regulate K48-linked ubiquitination and degradation of VDAC1.Our present study indicates that NEDD4-1 is a suppressor of AILI and functions by regulating the degradation of VDAC1.展开更多
Background Alzheimer’s disease(AD)exhibits mitochondrial dysfunctions associated with dysregulated metabolism,brain inflammation,synaptic loss,and neuronal cell death.As a key protein serving as the mitochondrial gat...Background Alzheimer’s disease(AD)exhibits mitochondrial dysfunctions associated with dysregulated metabolism,brain inflammation,synaptic loss,and neuronal cell death.As a key protein serving as the mitochondrial gatekeeper,the voltage-dependent anion channel-1(VDAC1)that controls metabolism and Ca2+homeostasis is positioned at a convergence point for various cell survival and death signals.Here,we targeted VDAC1 with VBIT-4,a newly developed inhibitor of VDAC1 that prevents its pro-apoptotic activity,and mitochondria dysfunction.Methods To address the multiple pathways involved in AD,neuronal cultures and a 5×FAD mouse model of AD were treated with VBIT-4.We addressed multiple topics related to the disease and its molecular mechanisms using immunoblotting,immunofluorescence,q-RT-PCR,3-D structural analysis and several behavioral tests.Results In neuronal cultures,amyloid-beta(Aβ)-induced VDAC1 and p53 overexpression and apoptotic cell death were prevented by VBIT-4.Using an AD-like 5×FAD mouse model,we showed that VDAC1 was overexpressed in neurons surrounding Aβplaques,but not in astrocytes and microglia,and this was associated with neuronal cell death.VBIT-4 prevented the associated pathophysiological changes including neuronal cell death,neuroinflammation,and neuro-metabolic dysfunctions.VBIT-4 also switched astrocytes and microglia from being pro-inflammatory/neurotoxic to neuroprotective phenotype.Moreover,VBIT-4 prevented cognitive decline in the 5×FAD mice as evaluated using several behavioral assessments of cognitive function.Interestingly,VBIT-4 protected against AD pathology,with no significant change in phosphorylated Tau and only a slight decrease in Aβ-plaque load.Conclusions The study suggests that mitochondrial dysfunction with its gatekeeper VDAC1 is a promising target for AD therapeutic intervention,and VBIT-4 is a promising drug candidate for AD treatment.展开更多
基金This work was supported by a grant from Beijing Nature Science Foundation （Grant No. 7132147）. We sincerely thank Professor Guangju Ji for kindly providing plasmid Mito-GCaMP3 for us.
文摘Mitochondrial calcium uniporter （MCU） is a conserved Ca2＋ transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress- induced cell death remains unclear. Here, we showed that ectopically expressed MCU is mitochondrial local- ized in both HeLa and primary cerebellar granule neu- rons （CGNs）. Knockdown of endogenous MCU decreases mitochondrial Ca2＋ uptake following his- tamine stimulation and attenuates cell death induced by oxidative stress in both HeLa cells and CGNs. We also found MCU interacts with VDACl and mediates VDAC1 overexpression-induced cell death in CGNs. This finding demonstrates that MCU-VDACl complex regulates mi- tochondrial Ca2＋ uptake and oxidative stress-induced apoptosis, which might represent therapeutic targets for oxidative stress related diseases.
基金supported by the National Natural Science Foundation of China(Beijing,ChinaGrant Nos.32022084 and 32172927)。
文摘Acetaminophen(APAP)overdose is a major cause of liver injury.Neural precursor cell expressed developmentally downregulated 4—1(NEDD4-1)is an E3 ubiquitin ligase that has been implicated in the pathogenesis of numerous liver diseases;however,its role in APAP-induced liver injury(AILI)is unclear.Thus,this study aimed to investigate the role of NEDD4-1 in the pathogenesis of AILI.We found that NEDD4-1 was dramatically downregulated in response to APAP treatment in mouse livers and isolated mouse hepatocytes.Hepatocyte-specific NEDD4-1 knockout exacerbated APAP-induced mitochondrial damage and the resultant hepatocyte necrosis and liver injury,while hepatocyte-specific NEDD4-1 overexpression mitigated these pathological events both in vivo and in vitro.Additionally,hepatocyte NEDD4-1 deficiency led to marked accumulation of voltage-dependent anion channel 1(VDAC1)and increased VDAC1 oligomerization.Furthermore,VDAC1 knockdown alleviated AILI and weakened the exacerbation of AILI caused by hepatocyte NEDD4-1 deficiency.Mechanistically,NEDD4-1 was found to interact with the PPTY motif of VDAC1 through its WW domain and regulate K48-linked ubiquitination and degradation of VDAC1.Our present study indicates that NEDD4-1 is a suppressor of AILI and functions by regulating the degradation of VDAC1.
基金The Israel Science Foundation,Grant No.974/19,and by a grant from the National Institute for Biotechnology in the Negev(NIBN)to VSB.
文摘Background Alzheimer’s disease(AD)exhibits mitochondrial dysfunctions associated with dysregulated metabolism,brain inflammation,synaptic loss,and neuronal cell death.As a key protein serving as the mitochondrial gatekeeper,the voltage-dependent anion channel-1(VDAC1)that controls metabolism and Ca2+homeostasis is positioned at a convergence point for various cell survival and death signals.Here,we targeted VDAC1 with VBIT-4,a newly developed inhibitor of VDAC1 that prevents its pro-apoptotic activity,and mitochondria dysfunction.Methods To address the multiple pathways involved in AD,neuronal cultures and a 5×FAD mouse model of AD were treated with VBIT-4.We addressed multiple topics related to the disease and its molecular mechanisms using immunoblotting,immunofluorescence,q-RT-PCR,3-D structural analysis and several behavioral tests.Results In neuronal cultures,amyloid-beta(Aβ)-induced VDAC1 and p53 overexpression and apoptotic cell death were prevented by VBIT-4.Using an AD-like 5×FAD mouse model,we showed that VDAC1 was overexpressed in neurons surrounding Aβplaques,but not in astrocytes and microglia,and this was associated with neuronal cell death.VBIT-4 prevented the associated pathophysiological changes including neuronal cell death,neuroinflammation,and neuro-metabolic dysfunctions.VBIT-4 also switched astrocytes and microglia from being pro-inflammatory/neurotoxic to neuroprotective phenotype.Moreover,VBIT-4 prevented cognitive decline in the 5×FAD mice as evaluated using several behavioral assessments of cognitive function.Interestingly,VBIT-4 protected against AD pathology,with no significant change in phosphorylated Tau and only a slight decrease in Aβ-plaque load.Conclusions The study suggests that mitochondrial dysfunction with its gatekeeper VDAC1 is a promising target for AD therapeutic intervention,and VBIT-4 is a promising drug candidate for AD treatment.
