Mitochondrial network architecture,which is closely related to mitochondrial function,is mechanically sensitive and regulated by multiple stimuli.However,the effects of microtopographic cues on mitochondria remain poo...Mitochondrial network architecture,which is closely related to mitochondrial function,is mechanically sensitive and regulated by multiple stimuli.However,the effects of microtopographic cues on mitochondria remain poorly defined.Herein,polycaprolactone(PCL)surfaces were used as models to investigate how micropatterns regulate mitochondrial network architecture and function in rat adipose-derived stem cells(rASCs).It was found that large pit(LP)-induced rASCs to form larger and more complex mitochondrial networks.Consistently,the expression of key genes related to mitochondrial dynamics revealed that mitochondrial fusion(MFN1 and MFN2)and midzone fission(DRP1 and MFF)were increased in rASCs on LP.In contrast,the middle pit(MP)-enhanced mitochondrial biogenesis,as evidenced by the larger mitochondrial area and higher expression of PGC-1.Both LP and MP promoted ATP production in rASCs.It is likely that LP increased ATP levels through modulating mitochondrial network architecture while MP stimulated mitochondria biogenesis to do so.Our study clarified the regulation of micropatterned surfaces on mitochondria,highlighting the potential of LP and MP as a simple platform to stimulate mitochondria and the subsequent cellular function of MSCs.展开更多
Mitochondria are subcellular organelles that provide energy for the cell.They form a dynamic tubular network and play an important role in maintaining the cell function and integrity.Heart is a powerful organ that sup...Mitochondria are subcellular organelles that provide energy for the cell.They form a dynamic tubular network and play an important role in maintaining the cell function and integrity.Heart is a powerful organ that supplies the motivation for circulation,thereby requiring large amounts of energy.Thus,the healthiness of cardiomyocytes and mitochondria is necessary for the normal cardiac function.Mitochondria not only lie in the center of the cell apoptotic pathway,but also are the major source of reactive oxygen species(ROS)generation.Mitochondrial morphological change includes fission and fusion that are regulated by a large number of proteins.In this review we discuss the regulators of mitochondrial fission/fusion and their association with cell apoptosis,autophagy and ROS production in the heart.展开更多
Objective:Activation of mitophagy is a promising option to overcome the mitochondrial malfunction that accompanies many diseases.Herein,we investigate the mechanisms underlying the ability of sodium lactate and pyruva...Objective:Activation of mitophagy is a promising option to overcome the mitochondrial malfunction that accompanies many diseases.Herein,we investigate the mechanisms underlying the ability of sodium lactate and pyruvate to initiate mitophagy,from the perspective of action on mitochondrial network and expression levels.Methods:Fluorescent and confocal microscopy was used to assess key cell parameters characterizing the state of the mitochondrial network and the level of mitophagy in human fibroblasts carrying mutations in genes encoding LRRK2 and PINK1 after the combined application of lactate and pyruvate and after direct acidification.qRT-PCR was used to study the expression levels of key mitophagy genes.Results:Cells with a mutation in the PINK1 gene showed a lower basal cytosolic pH.The application of sodium lactate and pyruvate to the cells with mutations associated with Parkinson’s disease caused intracellular acidification.Lowering extracellular pH to 6.0 led to a decrease in mitochondrial membrane potential,while the effect of lactate and pyruvate tended to increase this parameter.Extracellular acidification,as well as the effects of lactate and pyruvate,led to an increased level of mitophagy,and also affected such parameters of the mitochondrial network morphology as the ratio of individual to network mitochondria,branch length in mitochondrial network,number of mitochondrial junctions in the network,and also altered the expression of key mitophagy genes.Conclusion:Direct acidification and one induced by lactate and pyruvate do not differ in the efficiency of their effects on the mitochondrial network and mitophagy but change the cell fate differently.The mechanisms of acidification-induced activation of mitophagy differ in control and mutant fibroblasts.展开更多
Recent studies have revealed great functional and structural heterogeneity in the ribbon-type synapses at the basolateral pole of the isopotential inner hair cell(IHC).This feature is believed to be critical for audit...Recent studies have revealed great functional and structural heterogeneity in the ribbon-type synapses at the basolateral pole of the isopotential inner hair cell(IHC).This feature is believed to be critical for audition over a wide dynamic range,but whether the spatial gradient of ribbon morphology is fine-tuned in each IHC and how the mitochondrial network is organized to meet local energy demands of synaptic transmission remain unclear.By means of three-dimensional electron microscopy and artificial intelligence-based algorithms,we demonstrated the cell-wide structural quantification of ribbons and mitochondria in mature mid-cochlear IHCs of mice.We found that adjacent IHCs in staggered pairs differ substantially in cell body shape and ribbon morphology gradient as well as mitochondrial organization.Moreover,our analysis argues for a location-specific arrangement of correlated ribbon and mitochondrial function at the basolateral IHC pole.展开更多
Understanding the physiological processes underlying cardiovascular disease(CVD)requires examination of endothelial cell(EC)mitochondrial networks,because mitochondrial function and adenosine triphosphate production a...Understanding the physiological processes underlying cardiovascular disease(CVD)requires examination of endothelial cell(EC)mitochondrial networks,because mitochondrial function and adenosine triphosphate production are crucial in EC metabolism,and consequently influence CVD progression.Although current biochemical assays and immunofluorescence microscopy can reveal how mitochondrial function influences cellular metabolism,they cannot achieve live observation and tracking changes in mitochondrial networks through fusion and fission events.Holotomographic microscopy(HTM)has emerged as a promising technique for real-time,label-free visualization of ECs and their organelles,such as mitochondria.This nondestructive,noninterfering live cell imaging method offers unprecedented opportunities to observe mitochondrial network dynamics.However,because existing image processing tools based on immunofluorescence microscopy techniques are incompatible with HTM images,a machine-learning model is required.Here,we developed a model using a U-net learner with a Resnet18 encoder to identify four classes within HTM images:mitochondrial networks,cell borders,ECs,and background.This method accurately identifies mitochondrial structures and positions.With high accuracy and similarity metrics,the output image successfully provides visualization of mitochondrial networks within HTM images of ECs.This approach enables the study of mitochondrial networks and their effects,and holds promise in advancing understanding of CVD mechanisms.展开更多
基金supported by the National Natural Science Foundation of China(T2288101,31971266,82272152)Guangdong Basic and Applied Basic Research Foundation(2022A1515011925)+2 种基金National Key R&D Program of China(2021YFC2400700)Science and Technology Innovation Program of Guangdong Province Medical Products Administration(2022ZDZ11)Applied Basic Research Program of Guangzhou city of China(202201010040).
文摘Mitochondrial network architecture,which is closely related to mitochondrial function,is mechanically sensitive and regulated by multiple stimuli.However,the effects of microtopographic cues on mitochondria remain poorly defined.Herein,polycaprolactone(PCL)surfaces were used as models to investigate how micropatterns regulate mitochondrial network architecture and function in rat adipose-derived stem cells(rASCs).It was found that large pit(LP)-induced rASCs to form larger and more complex mitochondrial networks.Consistently,the expression of key genes related to mitochondrial dynamics revealed that mitochondrial fusion(MFN1 and MFN2)and midzone fission(DRP1 and MFF)were increased in rASCs on LP.In contrast,the middle pit(MP)-enhanced mitochondrial biogenesis,as evidenced by the larger mitochondrial area and higher expression of PGC-1.Both LP and MP promoted ATP production in rASCs.It is likely that LP increased ATP levels through modulating mitochondrial network architecture while MP stimulated mitochondria biogenesis to do so.Our study clarified the regulation of micropatterned surfaces on mitochondria,highlighting the potential of LP and MP as a simple platform to stimulate mitochondria and the subsequent cellular function of MSCs.
文摘Mitochondria are subcellular organelles that provide energy for the cell.They form a dynamic tubular network and play an important role in maintaining the cell function and integrity.Heart is a powerful organ that supplies the motivation for circulation,thereby requiring large amounts of energy.Thus,the healthiness of cardiomyocytes and mitochondria is necessary for the normal cardiac function.Mitochondria not only lie in the center of the cell apoptotic pathway,but also are the major source of reactive oxygen species(ROS)generation.Mitochondrial morphological change includes fission and fusion that are regulated by a large number of proteins.In this review we discuss the regulators of mitochondrial fission/fusion and their association with cell apoptosis,autophagy and ROS production in the heart.
基金supported by the Ministry of Science and Higher Education of the Russian Federation in the Framework of State Assignment of PSCBR RAS 075-00609-24-01(No.1022080100047-5-1.6.4,Neuroprotective drugs of a new generation).
文摘Objective:Activation of mitophagy is a promising option to overcome the mitochondrial malfunction that accompanies many diseases.Herein,we investigate the mechanisms underlying the ability of sodium lactate and pyruvate to initiate mitophagy,from the perspective of action on mitochondrial network and expression levels.Methods:Fluorescent and confocal microscopy was used to assess key cell parameters characterizing the state of the mitochondrial network and the level of mitophagy in human fibroblasts carrying mutations in genes encoding LRRK2 and PINK1 after the combined application of lactate and pyruvate and after direct acidification.qRT-PCR was used to study the expression levels of key mitophagy genes.Results:Cells with a mutation in the PINK1 gene showed a lower basal cytosolic pH.The application of sodium lactate and pyruvate to the cells with mutations associated with Parkinson’s disease caused intracellular acidification.Lowering extracellular pH to 6.0 led to a decrease in mitochondrial membrane potential,while the effect of lactate and pyruvate tended to increase this parameter.Extracellular acidification,as well as the effects of lactate and pyruvate,led to an increased level of mitophagy,and also affected such parameters of the mitochondrial network morphology as the ratio of individual to network mitochondria,branch length in mitochondrial network,number of mitochondrial junctions in the network,and also altered the expression of key mitophagy genes.Conclusion:Direct acidification and one induced by lactate and pyruvate do not differ in the efficiency of their effects on the mitochondrial network and mitophagy but change the cell fate differently.The mechanisms of acidification-induced activation of mitophagy differ in control and mutant fibroblasts.
基金the National Natural Science Foundation of China(81800901)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(QD2018015)+2 种基金the Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases(14DZ2260300)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB32030200)the Bureau of International Cooperation,Chinese Academy of Sciences(153D31KYSB20170059).
文摘Recent studies have revealed great functional and structural heterogeneity in the ribbon-type synapses at the basolateral pole of the isopotential inner hair cell(IHC).This feature is believed to be critical for audition over a wide dynamic range,but whether the spatial gradient of ribbon morphology is fine-tuned in each IHC and how the mitochondrial network is organized to meet local energy demands of synaptic transmission remain unclear.By means of three-dimensional electron microscopy and artificial intelligence-based algorithms,we demonstrated the cell-wide structural quantification of ribbons and mitochondria in mature mid-cochlear IHCs of mice.We found that adjacent IHCs in staggered pairs differ substantially in cell body shape and ribbon morphology gradient as well as mitochondrial organization.Moreover,our analysis argues for a location-specific arrangement of correlated ribbon and mitochondrial function at the basolateral IHC pole.
基金the National Institute of General Medical Sciences of the National Institutes of Health under Award Number SC2GM140991.
文摘Understanding the physiological processes underlying cardiovascular disease(CVD)requires examination of endothelial cell(EC)mitochondrial networks,because mitochondrial function and adenosine triphosphate production are crucial in EC metabolism,and consequently influence CVD progression.Although current biochemical assays and immunofluorescence microscopy can reveal how mitochondrial function influences cellular metabolism,they cannot achieve live observation and tracking changes in mitochondrial networks through fusion and fission events.Holotomographic microscopy(HTM)has emerged as a promising technique for real-time,label-free visualization of ECs and their organelles,such as mitochondria.This nondestructive,noninterfering live cell imaging method offers unprecedented opportunities to observe mitochondrial network dynamics.However,because existing image processing tools based on immunofluorescence microscopy techniques are incompatible with HTM images,a machine-learning model is required.Here,we developed a model using a U-net learner with a Resnet18 encoder to identify four classes within HTM images:mitochondrial networks,cell borders,ECs,and background.This method accurately identifies mitochondrial structures and positions.With high accuracy and similarity metrics,the output image successfully provides visualization of mitochondrial networks within HTM images of ECs.This approach enables the study of mitochondrial networks and their effects,and holds promise in advancing understanding of CVD mechanisms.
