Mitochondrial dysfunction and quality control lie at the heart of subarachnoid hemorrhage

The dramatic increase in intracranial pressure after subarachnoid hemorrhage leads to a decrease in cerebral perfusion pressure and a reduction in cerebral blood flow.Mitochondria are directly affected by direct factors such as ischemia,hypoxia,excitotoxicity,and toxicity of free hemoglobin and its degradation products,which trigger mitochondrial dysfunction.Dysfunctional mitochondria release large amounts of reactive oxygen species,inflammatory mediators,and apoptotic proteins that activate apoptotic pathways,further damaging cells.In response to this array of damage,cells have adopted multiple mitochondrial quality control mechanisms through evolution,including mitochondrial protein quality control,mitochondrial dynamics,mitophagy,mitochondrial biogenesis,and intercellular mitochondrial transfer,to maintain mitochondrial homeostasis under pathological conditions.Specific interventions targeting mitochondrial quality control mechanisms have emerged as promising therapeutic strategies for subarachnoid hemorrhage.This review provides an overview of recent research advances in mitochondrial pathophysiological processes after subarachnoid hemorrhage,particularly mitochondrial quality control mechanisms.It also presents potential therapeutic strategies to target mitochondrial quality control in subarachnoid hemorrhage.

Correlation between the gut microbiome and neurodegenerative diseases:a review of metagenomics evidence

A growing body of evidence suggests that the gut microbiota contributes to the development of neurodegenerative diseases via the microbiota-gut-brain axis.As a contributing factor,microbiota dysbiosis always occurs in pathological changes of neurodegenerative diseases,such as Alzheimer’s disease,Parkinson’s disease,and amyotrophic lateral sclerosis.High-throughput sequencing technology has helped to reveal that the bidirectional communication between the central nervous system and the enteric nervous system is facilitated by the microbiota’s diverse microorganisms,and for both neuroimmune and neuroendocrine systems.Here,we summarize the bioinformatics analysis and wet-biology validation for the gut metagenomics in neurodegenerative diseases,with an emphasis on multi-omics studies and the gut virome.The pathogen-associated signaling biomarkers for identifying brain disorders and potential therapeutic targets are also elucidated.Finally,we discuss the role of diet,prebiotics,probiotics,postbiotics and exercise interventions in remodeling the microbiome and reducing the symptoms of neurodegenerative diseases.

Mitophagy in intracerebral hemorrhage:a new target for therapeutic intervention

Intracerebral hemorrhage is a life-threatening condition with a high fatality rate and severe sequelae.However,there is currently no treatment available for intracerebral hemorrhage,unlike for other stroke subtypes.Recent studies have indicated that mitochondrial dysfunction and mitophagy likely relate to the pathophysiology of intracerebral hemorrhage.Mitophagy,or selective autophagy of mitochondria,is an essential pathway to preserve mitochondrial homeostasis by clearing up damaged mitochondria.Mitophagy markedly contributes to the reduction of secondary brain injury caused by mitochondrial dysfunction after intracerebral hemorrhage.This review provides an overview of the mitochondrial dysfunction that occurs after intracerebral hemorrhage and the underlying mechanisms regarding how mitophagy regulates it,and discusses the new direction of therapeutic strategies targeting mitophagy for intracerebral hemorrhage,aiming to determine the close connection between mitophagy and intracerebral hemorrhage and identify new therapies to modulate mitophagy after intracerebral hemorrhage.In conclusion,although only a small number of drugs modulating mitophagy in intracerebral hemorrhage have been found thus far,most of which are in the preclinical stage and require further investigation,mitophagy is still a very valid and promising therapeutic target for intracerebral hemorrhage in the long run.

Generation of mitochondrial replacement monkeys by female pronucleus transfer

Mutations in mitochondrial DNA(mtDNA)are maternally inherited and have the potential to cause severe disorders.Mitochondrial replacement therapies,including spindle,polar body,and pronuclear transfers,are promising strategies for preventing the hereditary transmission of mtDNA diseases.While pronuclear transfer has been used to generate mitochondrial replacement mouse models and human embryos,its application in non-human primates has not been previously reported.In this study,we successfully generated four healthy cynomolgus monkeys(Macaca fascicularis)via female pronuclear transfer.These individuals all survived for more than two years and exhibited minimal mtDNA carryover(3.8%–6.7%),as well as relatively stable mtDNA heteroplasmy dynamics during development.The successful establishment of this nonhuman primate model highlights the considerable potential of pronuclear transfer in reducing the risk of inherited mtDNA diseases and provides a valuable preclinical research model for advancing mitochondrial replacement therapies in humans.

Neural stem cell-derived exosomes promote mitochondrial biogenesis and restore abnormal protein distribution in a mouse model of Alzheimer's disease

Mitochondrial dysfunction is a hallmark of Alzheimer’s disease.We previously showed that neural stem cell-derived extracellular vesicles improved mitochondrial function in the cortex of AP P/PS1 mice.Because Alzheimer’s disease affects the entire brain,further research is needed to elucidate alterations in mitochondrial metabolism in the brain as a whole.Here,we investigated the expression of several important mitochondrial biogenesis-related cytokines in multiple brain regions after treatment with neural stem cell-derived exosomes and used a combination of whole brain clearing,immunostaining,and lightsheet imaging to clarify their spatial distribution.Additionally,to clarify whether the sirtuin 1(SIRT1)-related pathway plays a regulatory role in neural stem cell-de rived exosomes interfering with mitochondrial functional changes,we generated a novel nervous system-SIRT1 conditional knoc kout AP P/PS1mouse model.Our findings demonstrate that neural stem cell-de rived exosomes significantly increase SIRT1 levels,enhance the production of mitochondrial biogenesis-related fa ctors,and inhibit astrocyte activation,but do not suppress amyloid-βproduction.Thus,neural stem cell-derived exosomes may be a useful therapeutic strategy for Alzheimer’s disease that activates the SIRT1-PGC1αsignaling pathway and increases NRF1 and COXIV synthesis to improve mitochondrial biogenesis.In addition,we showed that the spatial distribution of mitochondrial biogenesis-related factors is disrupted in Alzheimer’s disease,and that neural stem cell-derived exosome treatment can reverse this effect,indicating that neural stem cell-derived exosomes promote mitochondrial biogenesis.

Latest assessment methods for mitochondrial homeostasis in cognitive diseases

Mitochondria play an essential role in neural function,such as supporting normal energy metabolism,regulating reactive oxygen species,buffering physiological calcium loads,and maintaining the balance of morphology,subcellular distribution,and overall health through mitochondrial dynamics.Given the recent technological advances in the assessment of mitochondrial structure and functions,mitochondrial dysfunction has been regarded as the early and key pathophysiological mechanism of cognitive disorders such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,mild cognitive impairment,and postoperative cognitive dysfunction.This review will focus on the recent advances in mitochondrial medicine and research methodology in the field of cognitive sciences,from the perspectives of energy metabolism,oxidative stress,calcium homeostasis,and mitochondrial dynamics(including fission-fusion,transport,and mitophagy).

Peripheral mitochondrial DNA as a neuroinflammatory biomarker for major depressive disorder

In the pathogenesis of major depressive disorder, chronic stress-related neuroinflammation hinders favorable prognosis and antidepressant response. Mitochondrial DNA may be an inflammatory trigger, after its release from stress-induced dysfunctional central nervous system mitochondria into peripheral circulation. This evidence supports the potential use of peripheral mitochondrial DNA as a neuroinflammatory biomarker for the diagnosis and treatment of major depressive disorder. Herein, we critically review the neuroinflammation theory in major depressive disorder, providing compelling evidence that mitochondrial DNA release acts as a critical biological substrate, and that it constitutes the neuroinflammatory disease pathway. After its release, mitochondrial DNA can be carried in the exosomes and transported to extracellular spaces in the central nervous system and peripheral circulation. Detectable exosomes render encaged mitochondrial DNA relatively stable. This mitochondrial DNA in peripheral circulation can thus be directly detected in clinical practice. These characteristics illustrate the potential for mitochondrial DNA to serve as an innovative clinical biomarker and molecular treatment target for major depressive disorder. This review also highlights the future potential value of clinical applications combining mitochondrial DNA with a panel of other biomarkers, to improve diagnostic precision in major depressive disorder.

Mitochondrial genomes of Tapes dorsatus and Cardita variegata:insights into Heteroconchia phylogeny

Heteroconchia,a widespread and abundant aquatic invertebrate,is an important clade of bivalve mollusks.The relationship between the three branches of Heteroconchia,Palaeoheterodonta,Archiheterodonta,and Euheterodonta has become a main controversy in molecular studies of the relationships between bivalves.In the present study,we assembled the complete mitochondrial genomes of Tapes dorsatus(Veneridae)and Cardita variegata(Carditidae)using high-throughput sequencing.C.variegata is the first mitochondrial genome belonging to the family Carditidae to be reported.We used 12 protein coding genes(excluding atp8)from the complete mitochondrial genomes of 146 species to recover the internal relationships of Heteroconchia.Our results support the traditional view of early branching of Palaeoheterodonta and the recovery of the monophyly of Palaeoheterodonta,Anomalodesmata,Imparidentia.Rearrangement analysis show that gene arrangement within Venerida was highly variable.Time-calibrated phylogenetic studies based on a relaxed molecular clock model suggested that Veneridae originated approximately 337.62 million years ago(Ma)and split into two major clades,whereas Carditidae originated approximately 510.09 Ma.Our results provide evidence of the internal relationships of Heteroconchia.

Resveratrol combats chronic diseases through enhancing mitochondrial quality

Resveratrol(RSV),as a functional food component extracted from natural plants,has been widely studied and recognized in preventing and treating various diseases,with major mechanisms including executing anti-inflammation and anti-oxidation functions,and improving mitochondrial quality.Chronic diseases as non-communicable diseases are mainly caused by multiple factors,such as physiological decline and dysfunction in the body,and have become a significant challenge on public health worldwide.It is worth noting that chronic diseases such as Alzheimer's disease(AD),Parkinson's disease(PD),muscle atrophy,cardiovascular disease,obesity,and cancer are accompanied by abnormal mitochondrial function.Therefore,targeted regulation of mitochondria may be a meaningful way to prevent and treat chronic diseases.Increasing evidence has confirmed that RSV is actively involved in regulating mitochondria,and it has become an essential consideration to prevent and treat chronic diseases through targeting mitochondria and improving corresponding functions.In this article,current studies on RSV to optimize mitochondrial quality for preventing and alleviating chronic disease are systematically summarized,which can provide a theoretical reference for the development of functional foods or drugs to combat chronic diseases.

Morphological and molecular analyses of a Philine kinglipini outbreak in summer of 2022 in Jiaozhou Bay,China

A sudden and unprecedented outbreak of molluscan Philine kinglipini occurred in summer 2022 in Jiaozhou Bay,Shandong,China,causing substantial damage to local mariculture industry of the Manila clam Ruditapes philippinarum.Although P.kinglipini has been found in many coastal regions of China,the molecular research of P.kinglipini has not been extensively studied,making it difficult to accurately identify and track P.kinglipini samples in field using molecular methods.Samples were collected during the outbreak and their morphological features and molecular sequences were analyzed.Results show that the causative species of the outbreak was P.kinglipini.The mitochondrial genome(mt DNA)of P.kinglipini was constructed for the first time,based on which phylogenetic analysis of the mt DNAs of P.kinglipini and related species in the order Cephalaspidea was carried out.As revealed by metabarcoding analysis of 18S rDNA V4,the seasonal change of P.kinglipini and closely related Philine species was striking with peaks between April and August.Therefore,metabarcoding analysis is applicable tool for monitoring the bloom development of P.kinglipini and related species.This study generated for the first time essential molecular marker sequences and mtDNA of P.kinglipini,which provided a reference for future characterization and monitoring of its outbreaks and for phylogenetic analysis of Philine species.

Rethinking neurodegenerative diseases:neurometabolic concept linking lipid oxidation to diseases in the central nervous system

Currently,there is a lack of effective medicines capable of halting or reve rsing the progression of neurodegenerative disorde rs,including amyotrophic lateral sclerosis,Parkinson s disease,multiple sclerosis,or Alzheimer s disease.Given the unmet medical need,it is necessary to reevaluate the existing para digms of how to to rget these diseases.When considering neurodegenerative diseases from a systemic neurometabolic perspective,it becomes possible to explain the shared pathological features.This innovative approach presented in this paper draws upon exte nsive research conducted by the authors and researchers worldwide.In this review,we highlight the importance of metabolic mitochondrial dysfunction in the context of neurodegenerative diseases.We provide an overview of the risk factors associated with developing neurodegenerative disorders,including genetic,epigenetic,and environmental fa ctors.Additionally,we examine pathological mechanisms implicated in these diseases such as oxidative stress,accumulation of misfolded proteins,inflammation,demyelination,death of neurons,insulin resistance,dysbiosis,and neurotransmitter disturbances.Finally,we outline a proposal for the restoration of mitochondrial metabolism,a crucial aspect that may hold the key to facilitating curative therapeutic interventions for neurodegenerative disorders in forthcoming advancements.

Low Selenium and Low Protein Exacerbate Myocardial Damage in Keshan Disease by Affecting the PINK1/Parkin-mediated Mitochondrial Autophagy Pathway

Objective Keshan disease(KD)is a myocardial mitochondrial disease closely related to insufficient selenium(Se)and protein intake.PTEN induced putative kinase 1(PINK1)/Parkin mediated mitochondrial autophagy regulates various physiological and pathological processes in the body.This study aimed to elucidate the relationship between PINK1/Parkin-regulated mitochondrial autophagy and KD-related myocardial injury.Methods A low Se and low protein animal model was established.One hundred Wistar rats were randomly divided into 5 groups(control group,low Se group,low protein group,low Se+low protein group,and corn from KD area group).The JC-1 method was used to detect the mitochondrial membrane potential(MMP).ELISA was used to detect serum creatine kinase MB(CK-MB),cardiac troponin I(cTnI),and mitochondrial-glutamicoxalacetic transaminase(M-GOT)levels.RT-PCR and Western blot analysis were used to detect the expression of PINK1,Parkin,sequestome 1(P62),and microtubule-associated proteins1A/1B light chain 3B(MAP1LC3B).Results The MMP was significantly decreased and the activity of CK-MB,cTnI,and M-GOT significantly increased in each experimental group(low Se group,low protein group,low Se+low protein group and corn from KD area group)compared with the control group(P<0.05 for all).The mRNA and protein expression levels of PINK1,Parkin and MAP1LC3B were profoundly increased,and those of P62 markedly decreased in the experimental groups compared with the control group(P<0.05 for all).Conclusion Low Se and low protein levels exacerbate myocardial damage in KD by affecting the PINK1/Parkin-mediated mitochondrial autophagy pathway.

Mitochondrial therapeutics and mitochondrial transfer for neurodegenerative diseases and aging

Mitochondrial dysfunction and neurodegeneration:Progressive neurodegenerative diseases affect a significant proportion of the population;in a single year,there are as many as 276 million disabilities and 9 million deaths as a result of neurological diseases.

Membrane vesicles derived from Streptococcus suis serotype 2 induce cell pyroptosis in endothelial cells via the NLRP3/Caspase-1/GSDMD pathway

Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.

Molecular phylogenetic relationships based on mitochondrial genomes of novel deep-sea corals(Octocorallia:Alcyonacea):Insights into slow evolution and adaptation to extreme deep-sea environments

A total of 10 specimens of Alcyonacea corals were collected at depths ranging from 905 m to 1633 m by the manned submersible Shenhai Yongshi during two cruises in the South China Sea(SCS).Based on mitochondrial genomic characteristics,morphological examination,and sclerite scanning electron microscopy,the samples were categorized into four suborders(Calcaxonia,Holaxonia,Scleraxonia,and Stolonifera),and identified as 9 possible new cold-water coral species.Assessments of GC-skew dissimilarity,phylogenetic distance,and average nucleotide identity(ANI)revealed a slow evolutionary rate for the octocoral mitochondrial sequences.The nonsynonymous(Ka)to synonymous(Ks)substitution ratio(Ka/Ks)suggested that the 14 protein-coding genes(PCGs)were under purifying selection,likely due to specific deep-sea environmental pressures.Correlation analysis of the median Ka/Ks values of five gene families and environmental factors indicated that the genes encoding cytochrome b(cyt b)and DNA mismatch repair protein(mutS)may be influenced by environmental factors in the context of deep-sea species formation.This study highlights the slow evolutionary pace and adaptive mechanisms of deep-sea corals.

Altered synaptic currents,mitophagy,mitochondrial dynamics in Alzheimer's disease models and therapeutic potential of Dengzhan Shengmai capsules intervention

Emerging research suggests a potential association of progression of Alzheimer's disease(AD)with alterations in synaptic currents and mitochondrial dynamics.However,the specific associations between these pathological changes remain unclear.In this study,we utilized Aβ42-induced AD rats and primary neural cells as in vivo and in vitro models.The investigations included behavioural tests,brain magnetic resonance imaging(MRI),liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)analysis,Nissl staining,thioflavin-S staining,enzyme-linked immunosorbent assay,Golgi-Cox staining,transmission electron microscopy(TEM),immunofluorescence staining,proteomics,adenosine triphosphate(ATP)detection,mitochondrial membrane potential(MMP)and reactive oxygen species(ROS)assessment,mitochondrial morphology analysis,electrophysiological studies,Western blotting,and molecular docking.The results revealed changes in synaptic currents,mitophagy,and mitochondrial dynamics in the AD models.Remarkably,intervention with Dengzhan Shengmai(DZSM)capsules emerged as a pivotal element in this investigation.Aβ42-induced synaptic dysfunction was significantly mitigated by DZSM intervention,which notably amplified the frequency and amplitude of synaptic transmission.The cognitive impairment observed in AD rats was ameliorated and accompanied by robust protection against structural damage in key brain regions,including the hippocampal CA3,primary cingular cortex,prelimbic system,and dysgranular insular cortex.DZSM intervention led to increased IDE levels,augmented long-term potential(LTP)amplitude,and enhanced dendritic spine density and length.Moreover,DZSM intervention led to favourable changes in mitochondrial parameters,including ROS expression,MMP and ATP contents,and mitochondrial morphology.In conclusion,our findings delved into the realm of altered synaptic currents,mitophagy,and mitochondrial dynamics in AD,concurrently highlighting the therapeutic potential of DZSM intervention.

Characterization,expression dynamics,and potential function of OPA1 for regulation of mitochondrial morphology during spermiogenesis in Phascolosoma esculenta

Mitochondria undergo morphological changes during spermatogenesis in some animals.The mechanism and role of mitochondrial morphology regulation,however,remain somewhat unclear.In this study,we analyzed the molecular characteristics,expression dynamics and subcellular localization of optic atrophy protein 1(OPA1),a mitochondrial fusion and cristae maintenance-related protein,to reveal the possible regulatory mechanisms underlying mitochondrial morphology in Phascolosoma esculenta spermiogenesis.The full-length cDNA of the P.esculenta opa1 gene(Pe-opa1)is 3743 bp in length and encodes 975 amino acids.The Pe-OPA1 protein is highly conservative and includes a transmembrane domain,a GTPase domain,two helical bundle domains,and a lipid-interacting stalk.Gene and protein expression was higher in the coelomic fluid(a site of spermatid development)of male P.esculenta and increased first and then decreased from March to December.Moreover,their expression during the breeding stage was significantly higher than during the non-breeding stage,suggesting that Pe-OPA1 is involved in P.esculenta reproduction.The Pe-OPA1 protein was more abundant in components consisting of many spermatids than in components without,indicating that Pe-OPA1 mainly plays a role in the spermatid in coelomic fluid.Moreover,Pe-OPA1 was mainly detected in the spermatid mitochondria.Immunofluorescence experiments showed that the Pe-OPA1 are constitutively expressed and co-localized with mitochondria during spermiogenesis,suggesting its involvement in P.esculenta spermiogenesis.These results provide evidence for Pe-OPA1's involvement in the regulation of mitochondrial morphology during spermiogenesis.

Mitochondrial targeting sequence of magnetoreceptor MagR:More than just targeting

Iron-sulfur clusters(ISC)are essential cofactors for proteins involved in various biological processes,such as electron transport,biosynthetic reactions,DNA repair,and gene expression regulation.ISC assembly protein IscA1(or MagR)is found within the mitochondria of most eukaryotes.Magnetoreceptor(MagR)is a highly conserved A-type iron and iron-sulfur cluster-binding protein,characterized by two distinct types of iron-sulfur clusters,[2Fe-2S]and[3Fe-4S],each conferring unique magnetic properties.MagR forms a rod-like polymer structure in complex with photoreceptive cryptochrome(Cry)and serves as a putative magnetoreceptor for retrieving geomagnetic information in animal navigation.Although the N-terminal sequences of MagR vary among species,their specific function remains unknown.In the present study,we found that the N-terminal sequences of pigeon MagR,previously thought to serve as a mitochondrial targeting signal(MTS),were not cleaved following mitochondrial entry but instead modulated the efficiency with which iron-sulfur clusters and irons are bound.Moreover,the N-terminal region of MagR was required for the formation of a stable MagR/Cry complex.Thus,the N-terminal sequences in pigeon MagR fulfil more important functional roles than just mitochondrial targeting.These results further extend our understanding of the function of MagR and provide new insights into the origin of magnetoreception from an evolutionary perspective.

Gene characterization and phylogenetic analysis of four mitochondrial genomes in Caenogastropoda

Caenogastropoda is a highly diverse group,containing~60%of all existing gastropods.Species in this subclass predominantly inhabit marine environments and have a high ecological and economic value.Owing to the increase in relevant phylogenetic studies,our understanding of between species relatedness in Caenogastropoda has improved.However,the biodiversity,taxonomic status,and phylogenetic relationships of this group remain unclear.In the present study,we performed next-generation sequencing of four complete mitochondrial genomes from three families(Buccinidae,Columbellidae,and Cypraeidae)and the four mitogenomes were classical circular structures,with a length of 16177 bp in Volutharpa ampullacea,16244 bp in Mitrella albuginosa,16926bp in Mauritia arabica asiatica and 15422 bp in Erronea errones.Base composition analysis indicated that whole sequences were biased toward A and T.Then compared them with 171 complete mitochondrial genomes of Caenogastropoda.The phylogenetic relationship of Caenogastropoda derived from Maximum Likelihood(ML)and Bayesian Inference(BI)trees constructed based on CDS sequences was consistent with the results of traditional morphological analysis,with all three families showing close relationships.This study supported Caenogastropoda at the molecular level as a separate clade of Mollusca.According to our divergence time estimations,Caenogastropoda was formed during the middle Triassic period(~247.2–237 Ma).Our novel mitochondrial genomes provide evidence for the speciation of Caenogastropoda in addition to elucidating the mitochondrial genomic evolution of this subclass.

Translocation of telomerase reverse transcriptase coincided with ATP release in postnatal cochlear supporting cells

The spontaneous bursts of electrical activity in the developing auditory system are derived from the periodic release of adenosine triphosphate(ATP)by supporting cells in the Kölliker’s organ.However,the mechanisms responsible for initiating spontaneous ATP release have not been determined.Our previous study revealed that telomerase reverse transcriptase(TERT)is expressed in the basilar membrane during the first postnatal week.Its role in cochlear development remains unclear.In this study,we investigated the expression and role of TERT in postnatal cochlea supporting cells.Our results revealed that in postnatal cochlear Kölliker’s organ supporting cells,TERT shifts from the nucleus into the cytoplasm over time.We found that the TERT translocation tendency in postnatal cochlear supporting cells in vitro coincided with that observed in vivo.Further analysis showed that TERT in the cytoplasm was mainly located in mitochondria in the absence of oxidative stress or apoptosis,suggesting that TERT in mitochondria plays roles other than antioxidant or anti-apoptotic functions.We observed increased ATP synthesis,release and activation of purine signaling systems in supporting cells during the first 10 postnatal days.The phenomenon that TERT translocation coincided with changes in ATP synthesis,release and activation of the purine signaling system in postnatal cochlear supporting cells suggested that TERT may be involved in regulating ATP release and activation of the purine signaling system.Our study provides a new research direction for exploring the spontaneous electrical activity of the cochlea during the early postnatal period.