Mitophagy in neurodegenerative disease pathogenesis

Mitochondria are critical cellular energy resources and are central to the life of the neuron.Mitophagy selectively clears damaged or dysfunctional mitochondria through autophagic machinery to maintain mitochondrial quality control and homeostasis.Mature neurons are postmitotic and consume substantial energy,thus require highly efficient mitophagy pathways to turn over damaged or dysfunctional mitochondria.Recent evidence indicates that mitophagy is pivotal to the pathogenesis of neurological diseases.However,more work is needed to study mitophagy pathway components as potential therapeutic targets.In this review,we briefly discuss the characteristics of nonselective autophagy and selective autophagy,including ERphagy,aggrephagy,and mitophagy.We then introduce the mechanisms of Parkin-dependent and Parkin-independent mitophagy pathways under physiological conditions.Next,we summarize the diverse repertoire of mitochondrial membrane receptors and phospholipids that mediate mitophagy.Importantly,we review the critical role of mitophagy in the pathogenesis of neurodegenerative diseases including Alzheimer’s disease,Parkinson’s disease,and amyotrophic lateral sclerosis.Last,we discuss recent studies considering mitophagy as a potential therapeutic target for treating neurodegenerative diseases.Together,our review may provide novel views to better understand the roles of mitophagy in neurodegenerative disease pathogenesis.

A novel mechanism of PHB2-mediated mitophagy participating in the development of Parkinson's disease

Endoplasmic reticulum stress and mitochondrial dysfunction play important roles in Parkinson s disease,but the regulato ry mechanism remains elusive.Prohibitin-2(PHB2)is a newly discove red autophagy receptor in the mitochondrial inner membrane,and its role in Parkinson’s disease remains unclear.Protein kinase R(PKR)-like endoplasmic reticulum kinase(PERK)is a factor that regulates cell fate during endoplasmic reticulum stress.Parkin is regulated by PERK and is a target of the unfolded protein response.It is unclear whether PERK regulates PHB2-mediated mitophagy thro ugh Parkin.In this study,we established a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of Parkinson’s disease.We used adeno-associated virus to knockdown PHB2 expression.Our res ults showed that loss of dopaminergic neurons and motor deficits were aggravated in the MPTP-induced mouse model of Parkinson’s disease.Ove rexpression of PHB2 inhibited these abnormalities.We also established a 1-methyl-4-phenylpyridine(MPP+)-induced SH-SY5Y cell model of Parkinson’s disease.We found that ove rexpression of Parkin increased co-localization of PHB2 and microtubule-associated protein 1 light chain 3,and promoted mitophagy.In addition,MPP+regulated Parkin involvement in PHB2-mediated mitophagy through phosphorylation of PERK.These findings suggest that PHB2 participates in the development of Parkinson’s disease by intera cting with endoplasmic reticulum stress and Parkin.

Crosstalk among mitophagy,pyroptosis,ferroptosis,and necroptosis in central nervous system injuries

Central nervous system injuries have a high rate of resulting in disability and mortality;however,at present,effective treatments are lacking.Programmed cell death,which is a genetically determined fo rm of active and ordered cell death with many types,has recently attra cted increasing attention due to its functions in determining the fate of cell survival.A growing number of studies have suggested that programmed cell death is involved in central nervous system injuries and plays an important role in the progression of brain damage.In this review,we provide an ove rview of the role of programmed cell death in central nervous system injuries,including the pathways involved in mitophagy,pyroptosis,ferroptosis,and necroptosis,and the underlying mechanisms by which mitophagy regulates pyroptosis,ferroptosis,and necro ptosis.We also discuss the new direction of therapeutic strategies to rgeting mitophagy for the treatment of central nervous system injuries,with the aim to determine the connection between programmed cell death and central nervous system injuries and to identify new therapies to modulate programmed cell death following central nervous system injury.In conclusion,based on these properties and effects,interventions targeting programmed cell death could be developed as potential therapeutic agents for central nervous system injury patients.

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.

Autophagy and mitophagy as potential therapeutic targets in diabetic heart condition:Harnessing the power of nanotheranostics

Autophagy and mitophagy pose unresolved challenges in understanding the pathology of diabetic heart condition(DHC),which encompasses a complex range of cardiovascular issues linked to diabetes and associated cardiomyopathies.Despite significant progress in reducing mortality rates from cardiovascular diseases(CVDs),heart failure remains a major cause of increased morbidity among diabetic patients.These cellular processes are essential for maintaining cellular balance and removing damaged or dysfunctional components,and their involvement in the development of diabetic heart disease makes them attractive targets for diagnosis and treatment.While a variety of conventional diagnostic and therapeutic strategies are available,DHC continues to present a significant challenge.Point-of-care diagnostics,supported by nanobiosensing techniques,offer a promising alternative for these complex scenarios.Although conventional medications have been widely used in DHC patients,they raise several concerns regarding various physiological aspects.Modern medicine places great emphasis on the application of nanotechnology to target autophagy and mitophagy in DHC,offering a promising approach to deliver drugs beyond the limitations of traditional therapies.This article aims to explore the potential connections between autophagy,mitophagy and DHC,while also discussing the promise of nanotechnology-based theranostic interventions that specifically target these molecular pathways.

Mitophagy in acute central nervous system injuries:regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries,including ischemic stro ke,intracerebral hemorrhage,subarachnoid hemorrhage,traumatic brain injury,and spinal co rd injury,are a major global health challenge.Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities.Mitochondria are susceptible to damage after acute central nervous system injury,and this leads to the release of toxic levels of reactive oxygen species,which induce cell death.Mitophagy,a selective form of autophagy,is crucial in eliminating redundant or damaged mitochondria during these events.Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries.In this review,we provide a comprehensive overview of the process,classification,and related mechanisms of mitophagy.We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy.In the final section of this review,we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Lindqvist-type Polyoxometalates Act as Anti-breast Cancer Drugs via Mitophagy-induced Apoptosis

Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using different cancer cell lines,the present study evaluated the antitumor activities of POM analogues that were modified at the body skeleton based on molybdenum-vanadium-centered negative oxygen ion polycondensations with different side strains.Cell colony formation assay,autophagy detection,mitochondrial observation,qRT-PCR,Western blotting,and animal model were used to evaluate the antitumor activities of POMs against breast cancer cells and the related mechanism.Results MO-4,a Lindqvist-type POM linking a proline at its side strain,was selected for subsequent experiments due to its low half maximal inhibitory concentration in the inhibition of proliferation of breast cancer cells.It was found that MO-4 induced the apoptosis of multiple types of breast cancer cells.Mechanistically,MO-4 activated intracellular mitophagy by elevating mitochondrial reactive oxygen species(ROS)levels and resulting in apoptosis.In vivo,breast tumor growth and distant metastasis were significantly reduced following MO-4 treatment.Conclusion Collectively,the results of the present study demonstrated that the novel Lindqvist-type POM MO-4 may exhibit potential in the treatment of breast cancer.

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.

From macroautophagy to mitophagy:Unveiling the hidden role of mitophagy in gastrointestinal disorders

In this editorial,we comment on an article titled“Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases”,which was published in a recent issue of the World Journal of Gastroenterology.We focused on the statement that“autophagy is closely related to the digestion,secretion,and regeneration of gastrointestinal cells”.With advancing research,autophagy,and particularly the pivotal role of the macroautophagy in maintaining cellular equilibrium and stress response in the gastrointestinal system,has garnered extensive study.However,the significance of mitophagy,a unique selective autophagy pathway with ubiquitin-dependent and independent variants,should not be overlooked.In recent decades,mitophagy has been shown to be closely related to the occurrence and development of gastrointestinal diseases,especially inflammatory bowel disease,gastric cancer,and colorectal cancer.The interplay between mitophagy and mitochondrial quality control is crucial for elucidating disease mechanisms,as well as for the development of novel treatment strategies.Exploring the pathogenesis behind gastrointestinal diseases and providing individualized and efficient treatment for patients are subjects we have been exploring.This article reviews the potential mechanism of mitophagy in gastrointestinal diseases with the hope of providing new ideas for diagnosis and treatment.

Heyingwuzi formulation alleviates diabetic retinopathy by promoting mitophagy via the HIF-1α/BNIP3/NIX axis

BACKGROUND Diabetic retinopathy(DR)is the primary cause of visual problems in patients with diabetes.The Heyingwuzi formulation(HYWZF)is effective against DR.AIM To determine the HYWZF prevention mechanisms,especially those underlying mitophagy.METHODS Human retinal capillary endothelial cells(HRCECs)were treated with high glucose(hg),HYWZF serum,PX-478,or Mdivi-1 in vitro.Then,cell counting kit-8,transwell,and tube formation assays were used to evaluate HRCEC proliferation,invasion,and tube formation,respectively.Transmission electron microscopy was used to assess mitochondrial morphology,and Western blotting was used to determine the protein levels.Flow cytometry was used to assess cell apoptosis,reactive oxygen species(ROS)production,and mitochondrial membrane potential.Moreover,C57BL/6 mice were established in vivo using streptozotocin and treated with HYWZF for four weeks.Blood glucose levels and body weight were monitored continuously.Changes in retinal characteristics were evaluated using hematoxylin and eosin,tar violet,and periodic acid-Schiff staining.Protein levels in retinal tissues were determined via Western blotting,immunohistochemistry,and immunostaining.RESULTS HYWZF inhibited excessive ROS production,apoptosis,tube formation,and invasion in hg-induced HRCECs via mitochondrial autophagy in vitro.It increased the mRNA expression levels of BCL2-interacting protein 3(BNIP3),FUN14 domain-containing 1,BNIP3-like(BNIP3L,also known as NIX),PARKIN,PTEN-induced kinase 1,and hypoxia-inducible factor(HIF)-1α.Moreover,it downregulated the protein levels of vascular endothelial cell growth factor and increased the light chain 3-II/I ratio.However,PX-478 and Mdivi-1 reversed these effects.Additionally,PX-478 and Mdivi-1 rescued the effects of HYWZF by decreasing oxidative stress and apoptosis and increasing mitophagy.HYWZF intervention improved the symptoms of diabetes,tissue damage,number of acellular capillaries,and oxidative stress in vivo.Furthermore,in vivo experiments confirmed the results of in vitro experiments.CONCLUSION HYWZF alleviated DR and associated damage by promoting mitophagy via the HIF-1α/BNIP3/NIX axis.

Role of mitophagy in the hallmarks of aging

Aging, subjected to scientific scrutiny, is extensively defined as a time-dependent decline in functions that involves the majority of organisms. The time-dependent accretion of cellular lesions is generally a universal trigger of aging, while mitochondrial dysfunction is a sign of aging. Dysfunctional mitochondria are identified and removed by mitophagy, a selective form of macroautophagy. Increased mitochondrial damage resulting from reduced biogenesis and clearance may promote the aging process. The primary purpose of this paper is to illustrate in detail the effects of mitophagy on aging and emphasize the associations between mitophagy and other signs of aging, including dietary restriction, telomere shortening, epigenetic alterations, and protein imbalance.The evidence regarding the effects of these elements on aging is still limited. And although the understanding of relationship between mitophagy and aging has been long-awaited, to analyze details of such a relationship remains the main challenge in aging studies.

Mitophagy-related gene signature predicts prognosis,immune infiltration and chemotherapy sensitivity in colorectal cancer

BACKGROUND Mitophagy plays essential role in the development and progression of colorectal cancer(CRC). However, the effect of mitophagy-related genes in CRC remains largely unknown.AIM To develop a mitophagy-related gene signature to predict the survival, immune infiltration and chemotherapy response of CRC patients.METHODS Non-negative matrix factorization was used to cluster CRC patients from Gene Expression Omnibus database(GSE39582, GSE17536, and GSE37892) based on mitophagy-related gene expression. The CIBERSORT method was applied for the evaluation of the relative infiltration levels of immune cell types. The performance signature in predicting chemotherapeutic sensitivity was generated using data from the Genomics of Drug Sensitivity in Cancer database.RESULTS Three clusters with different clinicopathological features and prognosis were identified. Higher enrichment of activated B cells and CD4+ T cells were observed in cluster Ⅲ patients with the most favorable prognosis. Next, a risk model based on mitophagy-related genes was developed. Patients in training and validation sets were categorized into low-risk and highrisk subgroups. Low risk patients showed significantly better prognosis, higher enrichment of immune activating cells and greater response to chemotherapy(oxaliplatin, irinotecan, and 5-fluorouracil) compared to high-risk patients. Further experiments identified CXCL3 as novel regulator of cell proliferation and mitophagy.CONCLUSION We revealed the biological roles of mitophagy-related genes in the immune infiltration, and its ability to predict patients’ prognosis and response to chemotherapy in CRC. These interesting findings would provide new insight into the therapeutic management of CRC patients.

Choline dehydrogenase interacts with SQSTM1 to activate mitophagy and promote coelomocyte survival in Apostichopus japonicus following Vibrio splendidus infection

Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes,leading to the production of excessive reactive oxygen species(ROS)and irreversible apoptotic cell death.Emerging evidence suggests that mitochondrial autophagy(mitophagy)is the most effective method for eliminating damaged mitochondria and ROS,with choline dehydrogenase(CHDH)identified as a novel mitophagy receptor that can recognize non-ubiquitin damage signals and microtubule-associated protein 1 light chain 3(LC3)in vertebrates.However,the functional role of CHDH in invertebrates is largely unknown.In this study,we observed a significant increase in the mRNA and protein expression levels of A.japonicus CHDH(AjCHDH)in response to V.splendidus infection and lipopolysaccharide(LPS)challenge,consistent with changes in mitophagy under the same conditions.Notably,AjCHDH was localized to the mitochondria rather than the cytosol following V.splendidus infection.Moreover,AjCHDH knockdown using si RNA transfection significantly reduced mitophagy levels,as observed through transmission electron microscopy and confocal microscopy.Further investigation into the molecular mechanisms underlying CHDH-regulated mitophagy showed that AjCHDH lacked an LC3-interacting region(LIR)for direct binding to LC3 but possessed a FB1 structural domain that binds to SQSTM1.The interaction between AjCHDH and SQSTM1 was further confirmed by immunoprecipitation analysis.Furthermore,laser confocal microscopy indicated that SQSTM1 and LC3 were recruited by AjCHDH in coelomocytes and HEK293T cells.In contrast,AjCHDH interference hindered SQSTM1 and LC3 recruitment to the mitochondria,a critical step in damaged mitochondrial degradation.Thus,AjCHDH interference led to a significant increase in both mitochondrial and intracellular ROS,followed by increased apoptosis and decreased coelomocyte survival.Collectively,these findings indicate that AjCHDH-mediated mitophagy plays a crucial role in coelomocyte survival in A.japonicus following V.splendidus infection.

Mechanisms of renal interstitial fibrosis: cross-talk between mitophagy and NLRP3 inflammasome

Renal interstitial fibrosis(RIF)is the main pathological basis leading to end-stage renal disease,and is closely related to the prognosis of patients with kidney disease.Increasing evidence as shown that mitophagy and NLRP3 inflammasome play important roles in the pathogenesis of RIF.Studies suggest that inhibiting NLRP3 inflammasome by activating mitophagy can prevent and alleviate RIF.This review summarizes role played by cross-talk between mitophagy and NLRP3 inflammasome in promoting RIF,so as to offer new perspectives on more effective slow the progression of renal diseases and fibrosis prevention.

Mitophagy links oxidative stress conditions and neurodegenerative diseases

Mitophagy is activated by a number of stimuli, including hypoxia, energy stress, and increased oxidative phosphorylation activity. Mitophagy is associated with oxidative stress conditions and central neurodegenerative diseases. Proper regulation of mitophagy is crucial for maintaining homeostasis; conversely, inadequate removal of mitochondria through mitophagy leads to the generation of oxidative species, including reactive oxygen species and reactive nitrogen species, resulting in various neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. These diseases are most prevalent in older adults whose bodies fail to maintain proper mitophagic functions to combat oxidative species. As mitophagy is essential for normal body function, by targeting mitophagic pathways we can improve these disease conditions. The search for effective remedies to treat these disease conditions is an ongoing process, which is why more studies are needed. Additionally, more relevant studies could help establish therapeutic conditions, which are currently in high demand. In this review, we discuss how mitophagy plays a significant role in homeostasis and how its dysregulation causes neurodegeneration. We also discuss how combating oxidative species and targeting mitophagy can help treat these neurodegenerative diseases.

The IL-33/ST2 axis affects tumor growth by regulating mitophagy in macrophages and reprogramming their polarization

Objective:Macrophages are a major component of the tumor microenvironment.M1 macrophages secrete pro-inflammatory factors that inhibit tumor growth and development,whereas tumor-associated macrophages(TAMs)mainly exhibit an M2 phenotype.Our previous studies have shown that the interleukin-33/ST2(IL-33/ST2)axis is essential for activation of the M1 phenotype.This study investigates the role of the IL-33/ST2 axis in TAMs,its effects on tumor growth,and whether it participates in the mutual conversion between the M1 and M2 phenotypes.Methods:Bone marrow-derived macrophages were extracted from wildtype,ST2 knockout(ST2-/-),and Il33-overexpressing mice and differentiated with IL-4.The mitochondrial and lysosomal number and location,and the expression of related proteins were used to analyze mitophagy.Oxygen consumption rates and glucose and lactate levels were measured to reveal metabolic changes.Results:The IL-33/ST2 axis was demonstrated to play an important role in the metabolic conversion of macrophages from OXPHOS to glycolysis by altering mitophagy levels.The IL-33/ST2 axis promoted enhanced cell oxidative phosphorylation,thereby further increasing M2 polarization gene expression and ultimately promoting tumor growth(P<0.05)(Figure 4).This metabolic shift was not due to mitochondrial damage,because the mitochondrial membrane potential was not significantly altered by IL-4 stimulation or ST2 knockout;however,it might be associated with the m TOR activity.Conclusions:These results clarify the interaction between the IL-33/ST2 pathway and macrophage polarization,and may pave the way to the development of new cancer immunotherapies targeting the IL-33/ST2 axis.

Insight into Crosstalk Between Mitophagy and Apoptosis/Necroptosis:Mechanisms and Clinical Applications in Ischemic Stroke

Ischemic stroke is a serious cerebrovascular disease with high morbidity and mortality.As a result of ischemia-reperfusion,a cascade of pathophysiological responses is triggered by the imbalance in metabolic supply and demand,resulting in cell loss.These cellular injuries follow various molecular mechanisms solely or in combination with this disorder.Mitochondria play a driving role in the pathophysiological processes of ischemic stroke.Once ischemic stroke occurs,damaged cells would respond to such stress through mitophagy.Mitophagy is known as a conservatively selective autophagy,contributing to the removal of excessive protein aggregates and damaged intracellular components,as well as aging mitochondria.Moderate mitophagy may exert neuroprotection against stroke.Several pathways associated with the mitochondrial network collectively contribute to recovering the homeostasis of the neurovascular unit.However,excessive mitophagy would also promote ischemia-reperfusion injury.Therefore,mitophagy is a double-edged sword,which suggests that maximizing the benefits of mitophagy is one of the direction of future efforts.This review emphasized the role of mitophagy in ischemic stroke,and highlighted the crosstalk between mitophagy and apoptosis/necroptosis.

Human survival and immune mediated mitophagy in neuroplasticity disorders

Dear editors,Neurodegenerative diseases are now associated with the global obesity and diabetes epidemic in the developing and developed world.Neurodegenerative diseases are a heterogeneous group of disorders with complex factors such as neurohumoral,endocrine and environmental factors involved in induction of these neurodegenerative diseases.The future of science and medicine in neurodegenerative diseases is now dependent on nutritional genomics with insulin resistance a major factor in the induction of neurodegenerative diseases.Nutritional genomics now involves the anti-aging gene Sirtuin 1(Sirt 1)that is important to the prevention of insulin resistance with its critical involvement in the immune system(Martins,2018a,b).Sirt 1 inactivation leads to toxic immune reactions connected to the acceleration of neuron death in various communities.Appetite control with relevance to immunometabolism has become of critical importance to the treatment of neurodegeneration(Figure 1).Nutritional diets activate the heat shock gene Sirt 1 to prevent the increase in heat shock proteins connected to autoimmune disease,mitophagy(Martins,2018a,b)and irreversible programmed cell death in global populations(Figure 1).

ROS-mediated BNIP3-dependent mitophagy promotes coelomocyte survival in Apostichopus japonicus in response to Vibrio splendidus infection

Organisms produce high levels of reactive oxygen species(ROS)to kill pathogens or act as signaling molecules to induce immune responses;however,excessive ROS can result in cell death.To maintain ROS balance and cell survival,mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates.In marine invertebrates,however,mitophagy and its functions remain largely unknown.In the current study,Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential(ΔΨm)and mitophagosome formation.The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide(LPS)treatment increased mitophagy flux.To explore the regulatory mechanism of mitophagy,we cloned Bcl2/adenovirus E1 B 19 kDa protein-interacting protein 3(BNIP3),a common mitophagy receptor,from sea cucumber Apostichopus japonicus(Aj BNIP3)and confirmed that Aj BNIP3 was significantly induced and accumulated in mitochondria after V.splendidus infection and LPS exposure.At the mitochondrial membrane,Aj BNIP3 interacts with microtubule-associated protein 1 light chain 3(LC3)on phagophore membranes to mediate mitophagy.After Aj BNIP3 interference,mitophagy flux decreased significantly.Furthermore,Aj BNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide(H2 O2),ROS scavengers,and ROS inhibitors.Finally,inhibition of BNIP3-mediated mitophagy by Aj BNIP3 small interfering RNA(si RNA)or high concentrations of lactate increased apoptosis and decreased coelomocyte survival.These findings highlight the essential role of Aj BNIP3 in damaged mitochondrial degradation during mitophagy.This mitophagy activity is required for coelomocyte survival in A.japonicus against V.splendidus infection.

Hepatitis C virus,mitochondria and auto/mitophagy:Exploiting a host defense mechanism

Hepatitis C virus(HCV)is the major reason for liver transplantation and the main cause of liver-related morbidity and mortality in a great number of countries.As for the other viruses,this pathogen interferes in more than one process and in more than one way with host cell biology.A mounting body of evidence points,in particular,toward the drastic alterations of mitochondrial physiology and functions that virus is able to induce,albeit the mechanisms have partly remained elusive.Role of the mitochondria in immunity and in quality control systems,as autophagy,as well as the strategies that HCV has evolved to evade and even to manipulate mitochondrial surveillance for its benefit,highlights the importance of deepening the mechanisms that modulate this virus-mitochondrion interaction,not only to intensify our knowledge of the HCV infection pathogenesis but also to design efficient antiviral strategies.