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Abstract Background High fat-fructose diet is a proinflammatory diet that increases risk of hepatocytes and myocytes steatosis and fibrosis. Finding anti-inflammatory strategies to fight these harmful effects is paid attention to nowadays. This study compared the effects of two widely anti-inflammatory interventions—metformin and intermittent fasting on myocytes and hepatocyte injury induced by proinflammatory diet and tracking possible underlying mechanisms. In this work, rats fed high fat-fructose diet were subdivided into untreated group, treated by metformin, and/or intermittent fasting. Results Metformin (300 mg/kg/day) and intermittent fasting (3 days/week) specially their combination for 4 weeks showed significant improvement in insulin resistance, lipid profile, antioxidants (p

Abstract Objective To investigate the role of Parkin overexpression-induecd mitophagy in alleviating acute lung injury of exertional heat stroke(EHS) rats. Methods Eighty SD rats were divided into four groups: Control group (CON group), Control Parkin overexpression group (CON + Parkin group), exertional heat stroke group (EHS group), and exertional heat stroke Parkin overexpression group (EHS + Parkin group). Adeno-associated virus carrying the Parkin gene was intravenously injected into the rats to overexpress Parkin in the lung tissue. An exertional heat stroke rat model was established, and survival curves were plotted. Lung Micro-CT was performed, and lung coefficient and pulmonary microvascular permeability were measured. Enzyme-linked immunosorbent assays(ELISA) were used to determine the levels of interleukin-6(IL-6), interleukin-1β(IL-1β), Tumor necrosis factor-α(TNF-α), and reactive oxygen species(ROS). The morphology of mitochondria in type II epithelial cells of lung tissue was observed using transmission electron microscopy. The apoptosis of lung tissue, the level of mitophagy, and the co-localization of Pink1 and Parkin were determined using immunofluorescence. The expression of Pink1, Parkin, MFN2, PTEN-L, PTEN, p62, and microtubule associated protein 1 light chain 3 (LC3) in rat lung tissue was measured by western blot. Results Compared with the CON group, there were more severe lung injury and more higher levels of IL-6, IL-1β, TNF-α in EHS rats. Both of the LC3-II/LC3-I ratio and the co-localization of LC3 and Tom20 in the lung tissue of EHS rats decreased. Compared with the EHS group, the survival rate of rats in the EHS + Parkin overexpression group was significantly increased, lung coefficient and pulmonary microvascular permeability were reduced, and pathological changes such as exudation and consolidation were significantly alleviated. The levels of IL-6, IL-1β, TNF-α, and ROS were significantly decreased; the degree of mitochondrial swelling in type II alveolar epithelial cells was reduced, and no vacuolization was observed. Lung tissue apoptosis was reduced, and the colocalization fluorescence of Pink1 and Parkin, as well as LC3 and Tom20, were increased. The expression of Parkin and LC3-II/LC3-I ratio in lung tissue were both increased, while the expression of P62, Pink1, MFN2, and PTEN-L was decreased. Conclusion Pink1/Parkin-mediated mitophagy dysfunction is one of the mechanisms underlying acute lung injury in rats with EHS, and activation of Parkin overexpression induced-mitophagy can alleviate acute lung injury caused by EHS.

PD is a complex, multifactorial neurodegenerative disease, which occurs sporadically in aged population, with some genetically linked cases. Patients develop a very obvious locomotor phenotype, with symptoms such as bradykinesia, resting tremor, muscular rigidity, and postural instability. At the cellular level, PD pathology is characterized by the presence of intracytoplasmic neurotoxic aggregates of misfolded proteins and dysfunctional organelles, resulting from failure in mechanisms of proteostasis. Nonmotor symptoms, such as constipation and olfactory deficits, are also very common in PD. They include alteration in the circadian clock, and defects in the sleep–wake cycle, which is controlled by the clock. These non-motor symptoms precede the onset of the motor symptoms by many years, offering a window of therapeutic intervention that could delay—or even prevent—the progression of the disease. The mechanistic link between aberrant circadian rhythms and neurodegeneration in PD is not fully understood, although proposed underlying mechanisms include alterations in protein homeostasis (proteostasis), which can impact protein levels of core components of the clock. Loss of proteostasis depends on the progressive pathological decline in the proteolytic activity of two major degradative systems, the ubiquitin-proteasome and the lysosome-autophagy systems, which is exacerbated in age-dependent neurodegenerative conditions like PD. Accordingly, it is known that promoting proteasome or autophagy activity increases lifespan, and rescues the pathological phenotype of animal models of neurodegeneration, presumably by enhancing the degradation of misfolded proteins and dysfunctional organelles, which are known to accumulate in these models, and to induce intracellular damage. We can enhance proteostasis by pharmacologically inhibiting or down-regulating Usp14, a proteasome-associated deubiquitinating enzyme (DUB). In a previous work, we showed that inhibition of Usp14 enhances the activity of the ubiquitin-proteasome system (UPS), autophagy and mitophagy, and abolishes motor symptoms of two well-established fly models of PD that accumulate dysfunctional mitochondria. In this work we extended the evidence on the protective effect of Usp14 down-regulation, and investigated the beneficial effect of down-regulating Usp14 in a Pink1 Drosophila model of PD that develop circadian and sleep dysfunction. We show that down-regulation of Usp14 ameliorates sleep disturbances and circadian defects that are associated to Pink1 KO flies.

Background: Sepsis-associated encephalopathy (SAE) is a disease characterized by neuroinflammation and cognitive dysfunction caused by systemic infection. Inflammation-induced microglial activation is closely associated with neuroinflammation in SAE. It is widely understood that melatonin has strong anti-inflammatory and immunomodulatory properties beneficial for sepsis-related brain damage. However, the mechanism of melatonin action in SAE has not been fully elucidated. Methods: The SAE cell model and SAE mouse model were induced by lipopolysaccharide (LPS). Behavioral tests were performed to analyze cognitive function. Microglial markers and M1/M2 markers were measured by immunofluorescence. Mitophagy was assessed by western blot, mt-Keima and transmission electron microscopy experiments. Immunoprecipitation and co-immunoprecipitation assays investigated the interactions between AMP-activated protein kinase α2 (AMPKα2) and PTEN-induced putative kinase 1 (PINK1). Results: Melatonin suppresses LPS-induced microglia M1 polarization by enhancing mitophagy, thereby attenuating LPS-induced neuroinflammation and behavioral deficits. However, inhibition or knockdown of AMPKα2 can inhibit the enhancement of melatonin on mitophagy, then weaken its promotion of microglia polarization towards M2 phenotype, and eliminate its protective effect on brain function. Furthermore, melatonin enhances mitophagy through activating AMPKα2, promotes PINK1 Ser495 site phosphorylation, and ultimately regulates microglial polarization from M1 to M2. Conclusions: Our findings demonstrate that melatonin facilitates microglia polarization towards M2 phenotype to alleviate LPS-induced neuroinflammation, primarily through AMPKα2-mediated enhancement of mitophagy.

Mitophagy is the cellular process to selectively eliminate dysfunctional mitochondria, governing the number and quality of mitochondria. Dysregulation of mitophagy may lead to the accumulation of damaged mitochondria, which plays an important role in the initiation and development of tumors. Mitophagy includes ubiquitin-dependent pathways mediated by PINK1/Parkin and non-ubiquitin dependent pathways mediated by mitochondrial autophagic receptors including NIX, BNIP3, and FUNDC1. Cellular mitophagy widely participates in multiple cellular process including metabolic reprogramming, anti-tumor immunity, ferroptosis, as well as the interaction between tumor cells and tumor-microenvironment. And cellular mitophagy also regulates tumor proliferation and metastasis, stemness, chemoresistance, resistance to targeted therapy and radiotherapy. In this review, we summarized the underlying molecular mechanisms of mitophagy and discussed the complex role of mitophagy in diverse contexts of tumors, indicating it as a promising target in the mitophagy-related anti-tumor therapy.

Background & Aims: Hepatic ischemia-reperfusion injury is a significant complication of partial hepatic resection and liver transplantation, impacting the prognosis of patients undergoing liver surgery. The protein proprotein convertase subtilisin/kexin type 9 (PCSK9) is primarily synthesized by hepatocytes and has been implicated in myocardial ischemic diseases. However, the role of PCSK9 in hepatic ischemia-reperfusion injury remains unclear. This study aims to investigate the role and mechanism of PCSK9 in hepatic ischemia-reperfusion injury. Methods: We first examined the expression of PCSK9 in mouse warm ischemia-reperfusion models and AML12 cells subjected to hypoxia/reoxygenation. Subsequently, we explored the impact of PCSK9 on liver ischemia-reperfusion injury by assessing mitochondrial damage and the resulting inflammatory response. Results: Our findings reveal that PCSK9 is up-regulated in response to ischemia-reperfusion injury and exacerbates hepatic ischemia-reperfusion injury. Blocking PCSK9 can alleviate hepatocyte mitochondrial damage and the consequent inflammatory response mediated by ischemia-reperfusion. Mechanistically, this protective effect is dependent on mitophagy. Conclusions: Inhibiting PCSK9 in hepatocytes attenuates the inflammatory responses triggered by reactive oxygen species and mitochondrial DNA by promoting PINK1-Parkin–mediated mitophagy. This, in turn, ameliorates hepatic ischemia-reperfusion injury.

ABSTRACTPINK1, mutated in familial forms of Parkinson’s disease, initiates mitophagy following mitochondrial depolarization. However, it is difficult to monitor this pathway physiologically in mice as loss of PINK1 does not alter basal mitophagy levels in most tissues. To further characterize this pathway in vivo, we used mito-QC mice in which loss of PINK1 was combined with the mitochondrial-associated POLGD257A mutation. We focused on skeletal muscle as gene expression data indicates that this tissue has the highest PINK1 levels. We found that loss of PINK1 in oxidative hindlimb muscle significantly reduced mitophagy. Of interest, the presence of the POLGD257A mutation, while having a minor effect in most tissues, restored levels of muscle mitophagy caused by the loss of PINK1. Although our observations highlight that multiple mitophagy pathways operate within a single tissue, we identify skeletal muscle as a tissue of choice for the study of PINK1-dependant mitophagy under basal conditions.

Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammatory disease characterised by irreversible airflow limitation. The elderly are a vulnerable population for developing COPD. With the growth of age, physiological degenerative changes occur in the thorax, bronchus, lung and vascular wall, which can lead to age-related physiological attenuation of lung function in the elderly, so the prevalence of COPD increases with age. Its pathogenesis has not yet been truly clarified. Mitophagy plays an important role in maintaining the stability of mitochondrial function and intracellular environment by scavenging damaged mitochondria. Currently, studies have shown that trophoblast antigen 2 (TROP2) expression is up-regulated in airway basal cells of patients with COPD, suggesting that TROP2 is involved in the progression of COPD. However, whether it is involved in disease progression by regulating mitochondrial function remains unclear. In this study, compared with non-smoking non-COPD patients, the expression of TROP2 in lung tissues of smoking non-COPD patients and patients with COPD increased, and TROP2 expression in patients with COPD was higher than that in smoking non-COPD patients. To further explore the role of TROP2, we stimulated BEAS-2B with cigarette smoke to construct an in vitro model. We found that TROP2 expression increased, whereas TROP2 silencing reversed the cigarette smoke extract-induced decrease in mitochondrial membrane potential, increased reactive oxygen species content, decreased adenosine triphosphate (ATP) production, increased inflammatory factor secretion and increased apoptosis. In addition, we searched online bioinformatics and screened the gene dynamin-related protein 1 (DRP1) related to mitophagy as the research object. Co-IP assay verified the binding relationship between DRP1 and TROP2. Further study found that TROP2 promoted mitophagy and apoptosis of BEAS-2B cells by up-regulating the expression of DRP1. In addition, PTEN-induced putative kinase 1 (PINK1) is a potential binding protein of DRP1, and DRP1 accelerated mitophagy and apoptosis of BEAS-2B cells by promoting the expression of PINK1. We established a COPD SD rat model by cigarette smoke exposure and LPS instillation and treated it by intraperitoneal injection of si-TROP2. The results showed that TROP2 silencing restored lung function and reduced the secretion of inflammatory factors in bronchoalveolar lavage fluid. In conclusion, TROP2 can be used as a new reference for COPD treatment.

Inorganic arsenic is a well-established environmental toxicant linked to acute liver injury, fibrosis, and cancer. While oxidative stress, pyroptosis, and ferroptosis are known contributors, the role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in arsenic-induced hepatic immunotoxicity remains underexplored. Our study revealed that acute arsenic exposure prompts differentiation of hepatic dendritic cells (DCs) and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cells, alongside increased transcription factors and cytokines. Inorganic arsenic triggered liver redox imbalance, leading to elevated alanine transaminase (ALT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and activation of nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway. PINK1-mediated mitophagy was initiated, and its inhibition exacerbates H2O2 accumulation while promoting DCs/Th1/Th2/Treg differentiation in the liver of arsenic-exposed mice. Mitoquinone (MitoQ) pretreatment relieved arsenic-induced acute liver injury and immune imbalance by activating Nrf2/HO-1 and PINK1-mediated mitophagy. To our knowledge, this is the first report identifying PINK1-mediated mitophagy as a protective factor against inorganic arsenic-induced hepatic DCs/Th1/Th2 differentiation. This study has provided new insights on the immunotoxicity of inorganic arsenic and established a foundation for exploring preventive and therapeutic strategies targeting PINK1-mediated mitophagy in acute liver injury. Consequently, the application of mitochondrial antioxidant MitoQ may offer a promising treatment for the metalloid-induced acute liver injury.

BackgroundsNumerous lines of evidence support the intricate interplay between Parkinson’s disease (PD) and the PINK1-dependent mitophagy process. This study aimed to evaluate differences in plasma PINK1 levels among idiopathic PD, PD syndromes (PDs), and healthy controls.MethodsA total of 354 participants were included, consisting of 197 PD patients, 50 PDs patients, and 107 healthy controls were divided into two cohorts, namely the modeling cohort (cohort 1) and the validated cohort (cohort 2). An enzyme-linked immunosorbent assay (ELISA)-based analysis was performed on PINK1 and α-synuclein oligomer (Asy-no). The utilization of the area under the curve (AUC) within the receiver-operating characteristic (ROC) curves served as a robust and comprehensive approach to evaluate and quantify the predictive efficacy of plasma biomarkers alone, as well as combined models, in distinguishing PD patients from controls.ResultsPINK1 and Asy-no were elevated in the plasma of PD and PDs patients compared to healthy controls. The AUCs of PINK1 (0.771) and Asy-no (0.787) were supposed to be potentially eligible plasma biomarkers differentiating PD from controls but could not differentiate PD from PDs. Notably, the PINK + Asy-no + Clinical RBD model showed the highest performance in the modeling cohort and was comparable with the PINK1 + Clinical RBD in the validation cohort. Moreover, there is no significant correlation between PINK1 and UPDRS, MMSE, HAMD, HAMA, RBDQ-HK, and ADL scores.ConclusionThese findings suggest that elevated PINK1 in plasma holds the potential to serve as a non-invasive tool for distinguishing PD patients from controls. Moreover, the outcomes of our investigation lend support to the plausibility of implementing a feasible blood test in future clinical translation.

The genes associated with autosomal recessive Parkinson's disease (PD) include the PRKN, PINK1, and DJ-1 genes. Homozygous and compound heterozygous carriers of pathogenic variants of these genes tend to display typical characteristics of PD at early ages.On the other hand, the ATP13A2, FBXO7, PLA2G6, SYNJ1, and DNAJC6 genes are associated with early-onset recessive forms that frequently present with pyramidal signs, ataxia, and oculomotor alterations, with early appearance of levodopa-induced motor fluctuations and dyskinesia. Such non-motor symptoms as depression, psychiatric disorders, hallucinations, and epilepsy are also more frequent in this group.Among multiple molecular mechanisms involved in these cases, key examples are the dysfunction of mitochondrial and lysosomal processes.This article presents a brief review intended to inform clinicians about the basic molecular mechanisms and phenotype–genotype relationship of these monogenic forms of PD. Resumen: Los genes asociados a enfermedad de Parkinson (EP) de herencia mendeliana autosómica recesiva incluyen PRKN, PINK1 y DJ-1. Los individuos portadores homocigotos o heterocigotos compuestos de variantes patogénicas en estos genes tienden a manifestar características típicas de la enfermedad de EP a edad temprana.Por otro lado, los genes ATP13A2, FBXO7, PLA2G6, SYNJ1, y DNAJC6, se asocian a formas recesivas de manifestación precoz, presentan con frecuencia signos piramidales, ataxia y alteraciones oculomotoras, y desarrollan tempranamente, fluctuaciones motoras y disquinesias inducidas por levodopa. Alteraciones no motoras como depresión, alteraciones psiquiátricas, alucinaciones y epilepsia son también más frecuentes en este grupo.Entre los múltiples aspectos moleculares comprometidos en estos casos, destacan la disfunción de procesos mitocondriales y lisosomales.En este artículo presentamos una breve revisión orientada al clínico sobre los aspectos moleculares básicos y relación fenotipo-genotipo de estas formas monogénicas de la EP.

Abstract Background Ovarian cancer is commonly associated with a poor prognosis due to metastasis and chemoresistance. PINK1 (PTEN-induced kinase 1) is a serine/threonine kinase that plays a crucial part in regulating various physiological and pathophysiological processes in cancer cells. Methods The ATdb database and "CuratedOvarianData" were used to evaluate the effect of kinases on ovarian cancer survival. The gene expression in ovarian cancer cells was detected by Western blot and quantitative real-time PCR. The effects of gene knockdown or overexpression in vitro were evaluated by wound healing assay, cell transwell assay, immunofluorescence staining, immunohistochemistry, and flow cytometry analysis. Mass spectrometry analysis, protein structure analysis, co-immunoprecipitation assay, nuclear-cytoplasmic separation, and in vitro kinase assay were applied to demonstrate the PINK1-PTEN (phosphatase and tensin homolog) interaction and the effect of this interaction. The metastasis experiments for ovarian cancer xenografts were performed in female BALB/c nude mice. Results PINK1 was strongly associated with a poor prognosis in ovarian cancer patients and promoted metastasis and chemoresistance in ovarian cancer cells. Although the canonical PINK1/PRKN (parkin RBR E3 ubiquitin protein ligase) pathway showed weak effects in ovarian cancer, PINK1 was identified to interact with PTEN and phosphorylate it at Serine179. Remarkably, the phosphorylation of PTEN resulted in the inactivation of the phosphatase activity, leading to an increase in AKT (AKT serine/threonine kinase) activity. Moreover, PINK1-mediated phosphorylation of PTEN impaired the nuclear import of PTEN, thereby enhancing the cancer cells’ ability to resist chemotherapy and metastasize. Conclusions PINK1 interacts with and phosphorylates PTEN at Serine179, resulting in the activation of AKT and the inhibition of PTEN nuclear import. PINK1 promotes ovarian cancer metastasis and chemotherapy resistance through the regulation of PTEN. These findings offer new potential therapeutic targets for ovarian cancer management.

Abstract Background The Parkinson’s disease (PD) gene family expression is strongly linked to tumor development and progression; PINK1 and PARK2 are essential members of the PD gene family. However, the relationship between PINK1 and PARK2 and esophageal squamous cell carcinoma (ESCC) remains unknown. This research aims to clarify the prognostic value of PINK1 and PARK2 in ESCC. Methods PINK1 and PARK2 protein levels in 232 ESCC specimens, and 125 matched adjacent normal tissues were detected by immunohistochemistry. The relationship between PINK1 and PARK2 protein expression and clinicopathological features were analyzed. Kaplan–Meier survival analysis was performed to estimate the prognostic value of the PINK1 and PARK2 proteins in patients. Cox univariate and multivariate analyses were used to assess the risk factors affecting the OS for patients with ESCC. Results PINK1 and PARK2 had low expression in ESCC. Patients with low PINK1 had worse differentiation and advanced T and TNM stages. Lower PARK2 expression was linked to lymph node metastases and an advanced TNM stage. Furthermore, reduced PINK1 and PARK2 levels were associated with a poor prognosis for ESCC. Cox univariate and multivariate analyses revealed that PINK1, PARK2, and tumor size were closely associated with the prognosis of patients with ESCC, and PARK2 was an independent risk factor for patients with ESCC. Finally, the PINK1 and PARK2 proteins were closely related and shared the same signal pathway. Conclusions PINK1 and PARK2 could work as tumor suppressors in ESCC and are likely to become new treatment targets for ESCC.

Abstract Background Fluoropyrimidine-based postoperative adjuvant chemotherapy is globally recommended for high-risk stage II and stage III colon cancer. However, adjuvant chemotherapy is often associated with severe adverse events and is not highly effective in preventing recurrence. Therefore, discovery of novel molecular biomarkers of postoperative adjuvant chemotherapy to identify patients at increased risk of recurrent colorectal cancer is warranted. Autophagy (including mitophagy) is activated under chemotherapy-induced stress and contributes to chemotherapy resistance. Expression of autophagy-related genes and their single-nucleotide polymorphisms are reported to be effective predictors of chemotherapy response in some cancers. Our goal was to evaluate the relationship between single-nucleotide variants of autophagy-related genes and recurrence rates in order to identify novel biomarkers that predict the effect of adjuvant chemotherapy in colorectal cancer. Methods We analyzed surgical or biopsy specimens from 84 patients who underwent radical surgery followed by fluoropyrimidine-based adjuvant chemotherapy at Saitama Medical University International Medical Center between January and December 2016. Using targeted enrichment sequencing, we identified single-nucleotide variants and insertions/deletions in 50 genes, including autophagy-related genes, and examined their association with colorectal cancer recurrence rates. Results We detected 560 single-nucleotide variants and insertions/deletions in the target region. The results of Fisher’s exact test indicated that the recurrence rate of colorectal cancer after adjuvant chemotherapy was significantly lower in patients with the single-nucleotide variants (c.1018G > A [p C [p

Mitochondria are crucial for cellular ATP production. They are highly dynamic organelles, whose morphology and function are controlled through mitochondrial fusion and fission. The specific roles of mitochondria in podocytes, the highly specialized cells of the kidney glomerulus, remain less understood. Given the significant structural, functional, and molecular similarities between mammalian podocytes and Drosophila nephrocytes, we employed fly nephrocytes to explore the roles of mitochondria in cellular function. Our study revealed that alterations in the Pink1–Park (mammalian PINK1–PRKN) pathway can disrupt mitochondrial dynamics in Drosophila nephrocytes. This disruption led to either fragmented or enlarged mitochondria, both of which impaired mitochondrial function. The mitochondrial dysfunction subsequently triggered defective intracellular endocytosis, protein aggregation, and cellular damage. These findings underscore the critical roles of mitochondria in nephrocyte functionality.

The oral colonization of periodontal pathogens onto gingival tissues establishes hypoxic microenvironment, often disrupting periodontal homeostasis in conjunction with oxidative stress. The association between reactive oxygen species (ROS) and osteolytic periodontitis have been suggested by recent studies. PTEN-induced kinase 1 (PINK1), a mitochondrial serine/threonine kinase, is an essential protein for mitochondrial quality control as it protects cells from oxidative stress by promoting degradation of damaged mitochondria through mitophagy. However, the pathophysiological roles of PINK1 in osteoclast-mediated bone loss have not been explored. Here we aimed to determine whether PINK1 plays a role in the regulation of osteoclastogenesis and alveolar bone resorption associated with periodontitis. C57BL/6 wild type (WT) and Pink1 knockout (KO) mice were subjected to ligature-induced periodontitis (LIP), and alveolar bones were evaluated by μCT-analysis and tartrate-resistant acid phosphatase (TRAP) staining. The μCT-analysis showed that bone volume fraction and travecular thickness were lower in Pink1 KO compared to WT mice. The number of TRAP-positive osteoclasts was markedly increased in the periodontal tissues of Pink1 KO mice with LIP. The genetic silencing or deletion of Pink1 promoted excessive osteoclast differentiation and bone resorption in vitro, as respectively indicated by TRAP staining and resorption pits on dentin slices. PINK1 deficiency led to mitochondrial instabilities as indicated by confocal microscopy of mitochondrial ROS, mitochondrial oxygen consumption rate (OCR) analysis, and transmission electron microscopy (TEM). Consequently, a significant increase in Ca2+-nuclear factor of activated T cells 1 (NFATc1) signaling was also found. On the other hand, restoration of mitophagy and autophagy by spermidine (SPD) treatment and the resolution of oxidative stress by N-acetyl-l-cysteine (NAC) treatment protected PINK1 deficiency-induced excessive generation of osteoclasts. Taken together, our findings demonstrate that PINK1 is essential for maintaining mitochondrial homeostasis during osteoclast differentiation. Therefore, targeting PINK1 may provide a novel therapeutic strategy for severe periodontitis with fulminant osteolysis.

Disease causing variants in several genes including PINK1 have been identified in hereditary Parkinsońs disease (PD). The mechanism behind this neuronal degeneration is not clarified but it is assumed that mitochondrial dysfunction, e.g. oxidative stress, might be involved. Here we describe the generation of an induced pluripotent stem cell clone (iPSC) KCi005-A from a female PD patient homozygous for the disease-causing variant c.1366C > T, p.Gln456* in PINK1. To obtain the iPSC clone we use a non-integrative self-replicating RNA vector. The clone might be a useful resource to study pathogenic mechanisms not only restricted to this variant.

ABSTRACT: The mitochondrial quality control system is crucial in maintaining cellular homeostasis during environmental stress. Granulosa cells are the main cells secreting steroid hormones, and mitochondria are the key organelles for steroid hormone synthesis. The impact of the mitochondrial quality control system on granulosa cells’ steroid hormone synthesis and survival under heat stress is still unclear. Here, we showed that acute heat stress induces mitochondrial damage and significantly increases the number of mitophagy-like vesicles in the cytoplasm of duck ovary granulosa cells at the ultra-structural level. Meanwhile, we also found heat stress significantly increased mitochondrial fission and mitophagy-related protein expression levels both in vivo and in vitro. Furthermore, by confocal fluorescence analysis, we discovered that LC3 was distributed spot-like manner near the nucleus in the heat treatment group, and the LC3 spots and lysosomes were colocalized with Mito-Tracker in the heat treatment group. We further detected the mitophagy-related protein in the cytoplasm and mitochondria, respectively. Results showed that the PINK1 protein was significantly increased both in cytoplasm and mitochondria, while the LC3-Ⅱ/LC3-Ⅰ ratio increase only occurred in mitochondrial. In addition, the autophagy protein induced by acute heat treatment was effectively inhibited by the mitophagy inhibitor CysA. Finally, we demonstrated that the alteration of cellular mitophagy by siRNA interference with Drp1 and PINK1 inhibited the steroid synthesis of granulosa cells and increased cell apoptosis. Study provides strong evidence that the Drp1 regulated PINK1-dependent mitophagy pathway protects follicular granulosa cells from acute heat stress-induced injury.

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have attracted attention in the field of regenerative medicine due to their potential ability to repair damaged hearts. However, the immature phenotype of these cells limits their clinical application. Cardiomyocyte maturation is accompanied by changes in mitochondrial quality. PTEN-induced putative kinase 1 (PINK1) has been linked to mitochondrial quality control. However, whether the changes in mitochondrial quality in hiPSC-CMs are associated with PINK1, and the impact of PINK1 on hiPSC-CMs development are not clear. In this study, we found that knockdown of PINK1 in hiPSC-CMs resulted in mitochondrial fragmentation and impaired mitochondrial functions such as mitophagy and mitochondrial biogenesis. PINK1 deletion also inhibited the maturation of hiPSC-CMs, reverting them to a naive structural and functional state. We found that restoring the mitochondrial structure did not completely rescue the mitochondrial dysfunction caused by PINK1 deletion, while activation of PINK1 kinase activity using kinetin promoted mitochondrial fusion, increased the mitochondrial membrane potential and ATP production, and maintained the development and maturation of hiPSC-CMs. In conclusion, PINK1 regulates the mitochondrial structure and function of hiPSC-CMs, and is essential for the maturation of hiPSC-CMs.

Abstract Background Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are seed cells that can be used for alternative treatment of myocardial damage. However, their immaturity limits their clinical application. Mitochondrial development accompanies cardiomyocyte maturation, and PINK1 plays an important role in the regulation of mitochondrial quality. However, the role and mechanism of PINK1 in cardiomyocyte development remain unclear. Methods We used proteomic and phosphoproteomic to identify protein and phosphosite changes in hiPSC-CMs deficient in PINK1. Bioinformatics analysis was performed to identify the potential biological functions and regulatory mechanisms of these differentially expressed proteins and validate potential downstream mechanisms. Results Deletion of PINK1 resulted in mitochondrial structural breakdown and dysfunction, accompanied by disordered myofibrils arrangement. hiPSC-CMs deficient in PINK1 exhibited significantly decreased expression of mitochondrial ATP synthesis proteins and inhibition of the oxidative phosphorylation pathway. In contrast, the expression of proteins related to cardiac pathology was increased, and the phosphoproteins involved in cytoskeleton construction were significantly altered. Mechanistically, PINK1 deletion damaged the mitochondrial cristae of hiPSC-CMs and reduced the efficiency of mitochondrial respiratory chain assembly. Conclusion The significantly differentially expressed proteins identified in this study highlight the important role of PINK1 in regulating mitochondrial quality in hiPSC-CMs. PINK1-mediated mitochondrial respiratory chain assembly is the basis for mitochondrial function. Whereas the cytoskeleton may be adaptively altered in response to mitochondrial dysfunction caused by PINK1 deletion, inadequate energy supply hinders myocardial development. These findings facilitate the exploration of the mechanism of PINK1 in cardiomyocyte development and guide efforts to promote the maturation of hiPSC-CMs.

Abstract Background Osteoarthritis (OA) is a prevalent disease plaguing the elderly. Recently, chondrocyte ferroptosis has been demonstrated to promote the progression of OA. Peroxisome proliferator-activated receptor-γ (PPARγ) is an important factor in maintaining cartilage health. However, the relationship between PPARγ and chondrocyte ferroptosis in OA and its mechanism is completely unclear. Methods We established a surgically induced knee OA rat model to investigate PPARγ and chondrocyte ferroptosis in OA. Rat knee specimens were collected for Safranin O/Fast Green staining and immunohistochemical staining after administered orally placebo or pioglitazone (PPARγ agonist) for 4 weeks. We used RSL3 to establish a chondrocyte ferroptosis model cultured in vitro to study the role of PPARγ activation toward ferroptosis, mitochondrial function, and PTEN-induced putative kinase 1 (Pink1)/Parkin-dependent mitophagy. GW9662 (PPARγ antagonist), Mdivi-1 (mitophagy inhibitor), and chloroquine (mitophagy inhibitor) were employed to investigate the mechanism of PPARγ-Pink1/Parkin-dependent mitophagy in the inhibition of ferroptosis. Results We found that PPARγ activation by pioglitazone attenuated not only OA but also inhibited the expression of the ferroptosis marker acyl-CoA synthetase long-chain family member 4 (ACSL4) at the same time in rats. Furthermore, in vivo and in vitro data indicated that PPARγ activation restored Pink1/Parkin-dependent mitophagy, improved mitochondrial function, inhibited chondrocyte ferroptosis, and delayed the progression of OA. Conclusions The present study demonstrated that PPARγ activation attenuates OA by inhibiting chondrocyte ferroptosis, and this chondroprotective effect was achieved by promoting the Pink1/Parkin-dependent mitophagy pathway.

Abstract Background Introducing new goat breeds or transferring adult goats from farms to slaughterhouses requires transportation, which can engender adverse effects, such as oxidative stress, pathological cell apoptosis and autophagy. Current evidence suggests that malondialdehyde (MDA) is a metabolite of lipid peroxidation during oxidative stress, while superoxide dismutase (SOD) and catalase (CAT) can alleviate injury caused by free radicals and reactive oxygen species (ROS). Meanwhile, Bcl-2, Bax, LC3B, PINK1 and Parkin are important proteins that participate in pathological cell apoptosis and autophagy. This study aimed to investigate the effects of transportation stress on oxidative stress indexes and expressions of Bcl-2, Bax, LC3B, PINK1 and Parkin in the small intestine of goats. Twelve healthy adult male goats from western Jiangxi province were randomly divided into control, 2 h transportation stress, and 6 h transportation stress groups (n = 4 per group). Results Our results showed that MDA in the small intestine significantly increased after transportation, while SOD and CAT activities decreased, with a significantly increased apoptosis rate of the small intestine cells. The jejunum and duodenum exhibited the highest apoptosis rate in the 2 h and 6 h transportation groups, respectively. The expression of apoptosis-related genes Bcl-2 and Bax and their corresponding proteins exhibited varying degrees of down-regulation or up-regulation, while Bcl-2 and Bax genes in the small intestine were upregulated in the 6 h transportation group. In addition, autophagosomes and autophagolysosomes were found in various parts of the small intestine by transmission electron microscopy, and autophagy-related genes LC3B, PINK1 and Parkin were significantly down-regulated in the 2 h group and up-regulated in the 6 h group. Conclusions Our results indicate that the contents of MDA, SOD and CAT in the small intestine, the expression of pathologic apoptosis-related genes Bcl-2 and Bax, and autophagy-related genes LC3B, PINK1 and Parkin correlated with stress duration caused by transportation. Moreover, this study provides a foothold for further studies on the mechanism of transportation stress in goats and improving animal welfare.

Mitochondrial dysfunction and aberrant mitochondrial homeostasis are key aspects of Parkinson's disease (PD) pathophysiology. Mutations in PINK1 and Parkin proteins lead to autosomal recessive PD, suggesting that defective mitochondrial clearance via mitophagy is key in PD etiology. Accelerating the identification and/or removal of dysfunctional mitochondria could therefore provide a disease-modifying approach to treatment. To that end, we performed a high-content phenotypic screen (HCS) of ∼125,000 small molecules to identify compounds that positively modulate mitochondrial accumulation of the PINK1-Parkin-dependent mitophagy initiation marker p-Ser65-Ub in Parkin haploinsufficiency (Parkin +/R275W) human fibroblasts. Following confirmatory counter-screening and orthogonal assays, we selected compounds of interest that enhance mitophagy-related biochemical and functional endpoints in patient-derived fibroblasts. Identification of inhibitors of the ubiquitin-specific peptidase and negative regulator of mitophagy USP30 within our hits further validated our approach. The compounds identified in this work provide a novel starting point for further investigation and optimization.

Abstract Background Recent studies indicate that endometrial hypoxia plays a critical role in adenomyosis (AM) development. Mitochondria are extremely sensitive to hypoxic damage, which can result in both morphological and functional impairment. Mitophagy is a crucial mechanism for preserving mitochondrial quality by selectively removing damaged mitochondria, thus ensuring the proper functioning of the entire mitochondrial network. In response to hypoxia, PINK1 is activated as a regulator of mitophagy, but its role in AM requires further study. Objective To explore the potential mechanism of mitophagy mediated by PINK1 in the pathogenesis of AM. Method The study compared PINK1, Parkin, OPTIN, P62, and NDP52 protein expression levels in patients with or without AM using clinical specimens and an AM mouse model. Pathological changes were compared using HE staining. Immunofluorescence and western blot were used to detect protein expression levels. Endometrial stromal cells (ESC) were isolated and examined for mitophagy, protein expression level, and cell invasion ability. Results Both the endometrial tissue from patients with AM and AM ESC displayed an upregulation of protein levels for PINK1, Parkin, OPTIN, P62, and NDP52 when compared with the control group. Then, HE staining confirmed the successful establishment of the AM mouse model. Moreover, the ultrastructural analysis using transmission electron microscopy revealed that AM mice’s endometrial glandular epithelial and stromal cells had exhibited swollen, deformed, and reduced mitochondria along with an increase in the number of lysosomes and mitochondrial autophagosomes. The protein levels of PINK1, Parkin, OPTIN, P62, and NDP52 in uterine tissue from AM mice were noticeably increased, accompanied by a considerable upregulation of ROS levels compared to the control group. In addition, cells in the AM group showed remarkably elevated mitophagy and invasion potentials compared to the control group. In contrast, the cell invasion ability decreased following PINK1 knockdown using the RNA interference technique. Conclusion The high levels of PINK1-mediated mitophagy have been found in AM. The upregulation in mitophagy contributes to mitochondrial damage, which may result in the abnormal invasion characteristic of AM.

Gaoyuan Wang,1 Xiaoyu Chen,2 Yubao Shao,2 Bin Xu1 1Department of Orthopaedics, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People’s Republic of China; 2Department of Histology and Embryology, Anhui Medical University, Hefei, Anhui, People’s Republic of ChinaCorrespondence: Bin Xu, Email youchen100@126.comIntroduction: To explore the role of PINK1/Parkin-mediated mitochondrial autophagy in H2O2-induced abnormal proliferation of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS).Methods: Firstly, we isolated fibroblast like synoviocytes (RA-FLS) from RA patients. H2O2-induced oxidative stress, and NAC (a ROS inhibitor) or FCCP (a mitochondrial autophagy activator) treatment inhibited ROS level or activate mitochondrial autophagy in RA-FLS. MitoSOX Red, JC-1 kit, DCFH-DA kit and CCK8 kit were used to evaluate mitochondrial redox status, mitochondrial membrane potential, intracellular ROS level and cell activity, respectively. Western blot was used to detect the protein expression. The rat model of Freund’s complete adjuvant arthritis (AA) was established and treated with NAC and FCCP, respectively. The pathological changes of synovium and the percentage of apoptotic cells in synovium were detected by H&E and TUNEL staining, respectively.Results: We have successfully isolated synovial cells from RA patients. Using 5μM H2O2 to stimulate RA-FLS could induce mitochondrial abnormalities of RA-FLS and inhibit RA-FLS autophagy. FCCP could reverse the effect of H2O2 on RA-FLS cell proliferation and apoptosis. NAC could reverse the effect of H2O2 on PINK1/Parkin. Overexpression of PINK1 or Parkin reversed the effect of H2O2 on RA-FLS mitochondrial autophagy, proliferation and apoptosis. The in vivo experiment results showed that both NAC and FCCP could prevent the pathogenesis of RA, reduce RA-FLS cell viability and increase RA-FLS cell apoptosis.Conclusion: The PINK1/Parkin-mediated mitochondrial autophagy participates in H2O2-induced abnormal proliferation of RA-FLS, and targeting of PINK1/Parkin-mediated mitochondrial autophagy may be the key mechanism in the treatment of RA.Keywords: mitochondrial autophagy, rheumatoid arthritis, PINK1, Parkin

Abstract Background Dendritic cell (DC) dysfunction plays a central role in sepsis-induced immunosuppression. Recent research has indicated that collective mitochondrial fragmentation contributes to the dysfunction of immune cells observed during sepsis. PTEN-induced putative kinase 1 (PINK1) has been characterized as a guide for impaired mitochondria that can keep mitochondrial homeostasis. However, its role in the function of DCs during sepsis and the related mechanisms remain obscure. In our study, we elucidated the effect of PINK1 on DC function during sepsis and its underlying mechanism of action. Methods Cecal ligation and puncture (CLP) surgery and lipopolysaccharide (LPS) treatment were used as in vivo and in vitro sepsis models, respectively. Results We found that changes in mitochondrial PINK1 expression of DCs paralleled changes in DC function during sepsis. The ratio of DCs expressing MHC-II, CD86, and CD80, the mRNAs level of dendritic cells expressing TNF-α and IL-12, and the level of DC-mediated T-cell proliferation were all decreased, both in vivo and in vitro during sepsis, when PINK1 was knocked out. This suggested that PINK1 knockout prevented the function of DCs during sepsis. Furthermore, PINK1 knockout inhibited Parkin RBR E3 ubiquitin protein (Parkin)-dependent mitophagy and enhanced dynamin-related protein 1 (Drp1)-related mitochondrial fission, and the negative effects of PINK1 knockout on DC function following LPS treatment were reversed by Parkin activation and Drp1 inhibitor. Knockout of PINK1 also increased apoptosis of DCs and the mortality of CLP mice. Conclusion Our results indicated that PINK1 protected against DC dysfunction during sepsis through the regulation of mitochondrial quality control.

Abstract Background Osteosarcoma is a common primary bone malignancy prevalent among adolescents and young adults. PTEN-induced kinase 1 (PINK1) regulates Parkinson's disease, but its role in cancers is unknown. Objective This study was designed to analyze the mechanism by which PINK1 affects osteosarcoma using bioinformatics and cell experiments. Materials and methods The gene expression profiles were downloaded from the TARGET database. Several online databases were used to analyze the expression and protein‒protein interaction networks. CCK-8 cell viability assays and cisplatin treatment were used to assess cell activity with or without cisplatin treatment. Acridine orange/ethidium bromide (AO/EB) fluorescence staining was used to calculate the percentage of apoptotic cells. Results Through bioinformatics analysis, we found that high expression of PINK1 was associated with poor prognosis in patients with osteosarcoma, and PINK1 inhibited apoptosis and promoted proliferation pathways. Next, we found that both PINK1 mRNA and protein levels were upregulated in osteosarcoma tissues. Additionally, we found that PTEN was reduced, while FOXO3a was markedly increased in osteosarcoma, suggesting that FOXO3a and not PTEN induced the overexpression of PINK1. CCK-8 and clonogenic assays showed that the knockdown of PINK1 decreased the growth of U2OS osteosarcoma cells. Ki67 immunofluorescence staining revealed that reduced cell proliferation in U2OS cells resulted in the depletion of PINK1. In addition, our AO/EB staining results indicated that the knockdown of PINK1 resulted in an increase in apoptotic cells and increased the levels of cleaved caspase-3. Furthermore, our experiments revealed that cisplatin promotes OS cell apoptosis by downregulating PINK1. Conclusion Collectively, our findings demonstrate that PINK1 is crucially involved in osteosarcoma and suggests that it can promote the apoptosis of OS cells as the downstream target gene of cisplatin.

Background: Glucocorticoid (GC) is one of frequently used anti-inflammatory agents, but its administration is unfortunately accompanied with bone loss. Although sporadic studies indicated that osteocytes are subject to a series of pathological changes under GC stress, including overexpression of cathepsin K, the definite role of osteocytes in GC-induced bone loss remains largely unclear. Methods: Gene expression of Ctsk and protein levels of cathepsin K were assessed in MLO-Y4 cell lines exposed to dexamethasone (Dex) of different time (0, 12, 24 hours) and dose (0, 10−8 and 10−6 M) courses by RT-qPCR and western blotting, respectively. Confocal imaging and immunostaining were then performed to evaluate the effects of osteocyte-derived cathepsin K on type I collagen in a primary osteocyte ex vivo culture system. MitoTracker Red was used to stain mitochondria for mitochondria morphology assessment and JC-1 assay was employed to evaluate the mitochondria membrane potential in MLO-Y4 cells following Dex treatment. Activation of PINK1-mediated mitophagy was evaluated by immunostaining of the PINK1 protein and CytoID assay. Mdivi-1 was used to inhibit mitophagy and siRNAs were used for the inhibition of Pink1 and Atg5. Results: GC triggered osteocytes to produce excessive cathepsin K which in turn led to the degradation of type I collagen in the extracellular matrix in a primary osteocyte ex vivo culture system. Meanwhile, GC administration increased mitochondrial fission and membrane depolarization in osteocytes. Further, the activation of PINK1-mediated mitophagy was demonstrated to be responsible for the diminishment of dysfunctional mitochondria in osteocytes. Examination of relationship between mitophagy and cathepsin K production revealed that inhibition of mitophagy via knocking down Pink1 gene abolished the GC-triggered cathepsin K production. Interestingly, GC’s activation effect towards cathepsin K via mitophagy was found to be independent on the canonical autophagy as this effect was not impeded when inhibiting the canonical autophagy via Atg5 suppression. Conclusion: GC-induced PINK1-mediated mitophagy substantially modulates the production of cathepsin K in osteocytes, which could be an underlying mechanism by which osteocytes contribute to the extracellular matrix degradation during bone loss. The Translational potential of this article: Findings of the current study indicate a possible role of osteocyte mitophagy in GC-induced bone loss, which provides a potential therapeutic approach to alleviate GC-induced osteoporosis by targeting PINK1-mediated osteocytic mitophagy.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma. Zinc oxide (ZnO) nanoparticles have excellent anti-tumor properties in the biomedical field. The present study aimed to explore the underlying mechanism by which ZnO nanoparticles induce toxicity in DLBCL cells (U2932) via the PINK1/Parkin-mediated mitophagy pathway. After U2932 cells were exposed to various concentrations of ZnO nanoparticles, the cell survival rate, reactive oxygen species (ROS) generation, cell cycle arrest, and changes in the expression of PINK1, Parkin, P62, and LC3 were monitored. Moreover, we investigated monodansylcadaverine (MDC) fluorescence intensity and autophagosome and further validated the results using the autophagy inhibitor 3-methyladenine (3-MA). The results showed that ZnO nanoparticles could effectively inhibit the proliferation of U2932 cells and induce cell cycle arrest at the G0/G1 phases. Moreover, ZnO nanoparticles significantly increased ROS production, MDC fluorescence intensity, autophagosome formation, and the expression of PINK1, Parkin, and LC3, and decreased the expression of P62 in U2932 cells. In contrast, the autophagy level was reduced after the intervention of the 3-MA. Overall, ZnO nanoparticles can trigger PINK1/Parkin-mediated mitophagy signaling in U2932 cells, which may be a potential therapeutic approach for DLBCL.

Differentiating stem cells must adapt their mitochondrial metabolism to fit the needs of the mature differentiated cell. In a recent study, we observed that during differentiation to an endothelial phenotype, pluripotent stem cell mitochondria are removed by mitophagy, triggering compensatory mitochondrial biogenesis to replenish the mitochondrial pool. We identified the mitochondrial phosphatase PGAM5 as the link between mitophagy and transcription of the mitochondrial biogenesis regulator PPARGC1A/PGC1α in the nucleus. Swapping of mitochondria through the coupled processes of mitophagy and mitochondrial biogenesis lead to enhanced metabolic reprogramming in the differentiated cell.

Background & objectives: Parkinson's disease is a progressive neurological disorder associated with the destruction of dopaminergic neurons in the substantia nigra. Physical exercise can control the risk of neuronal damage. The compounds of olive oil have a modulating effect on the activity of the brain cholinergic system. The present study aimed to investigate 8 weeks of combined aerobic resistance training with olive oil consumption on the balance and some apoptotic genes of the substantia nigra of the brain in Parkinsonian rats. Methods: Forty- eight male rats were divided into 8 groups (n=6). 6-Hydroxydopamine was used to induce Parkinson's disease. Olive oil (0.4ml/daily) was fed for 8 weeks to the target group. Thirty minutes aerobic exercise was performed on a treadmill at a speed of 11 meters per minute with an intensity of 60 to 65% of VO2max. Resistance exercise started by climbing a ladder with weights to the rat's tail with 30% of body weight, which reached 100% of body weight at the end of the eighth week. To check the balance of the mice, a balance bar was used; the expression level of genes was measured using Real time-PCR method. Statistical analysis was performed using one-way analysis of variance and Thomhan's post hoc test at a significance level of p0.05). Balance improvement was observed in rats with exercise and olive oil consumption compared to the parkinsonian group (p=0.001). Conclusion: 8 weeks of combined resistance-aerobic training causes a significant increase in the expression level of AKT and PINK1 genes and a decrease in the expression level of caspase-3 and P53 genes in Parkinsonian rats. Also, this type of exercise, along with the consumption of olive oil improves balance in Parkinsonian rats.

Treatment using the immunosuppressive drug tacrolimus (TAC) is related to new-onset diabetes after transplantation (NODAT). Previous studies focused mainly on islet β cells in the diabetogenic effect of TAC. Herein, we revealed that NODAT was probably induced by TAC via hepatic insulin resistance. After daily injection of mice with TAC, a glucose metabolism disorder was induced. In addition, TAC decreased the mRNA and protein levels of insulin receptor substrate 2 (IRS2), glucose transporter type 2 (GLUT2), and the phosphorylation of protein kinase B beta (pAKT2), which indicated impaired hepatic insulin signaling. Furthermore, the PTEN-induced novel kinase 1(PINK1)/Parkin pathway was shown to have a key role in the TAC-induced imbalance of hepatic glucose homeostasis. Mechanistic investigations in human hepatic cell lines revealed that TAC stimulated PINK1/Parkin expression and inhibited the expression of insulin signaling related molecules (e.g., IRS2, GLUT2 and pAKT2). Knockdown of hepatic PINK1 regulated downstream molecules of the PINK1/Parkin pathway (GLUT2 and IRS2), which reversed TAC-induced insulin resistance. Thus, in the liver, PINK1/Parkin signaling plays an important role in the TAC-induced imbalance of glucose homeostasis. TAC-induced diabetes might be prevented using Targeted treatment.

The combination of glyphosate (Gly) and hard water (Hwt) is a suspected risk factor for chronic interstitial nephritis in agricultural communities (CINAC). Accumulated mitochondrial damage and proximal tubular epithelial (PTE) cell senescence have been implicated in CINAC pathogenesis. Melatonin (Mel) has potential mitochondrial function and renoprotective properties, but its role and mechanism in CINAC are unknown. Here, we detected PTE cell senescence and PTEN-induced putative protein kinase 1 (PINK1)-parkin RBR E3 ubiquitin protein ligase (Parkin)-dependent mitophagy in mice orally administered with different doses of Gly combined with Hwt (Gly: 100 mg/kg·bw and 0.7 mg/L; Hwt: 2,500 mg/L CaCO3 and 250 mg/L Ca2+) for different durations (12 and 36 w) using histological examination, transmission electron microscopy (TEM), immunofluorescence (IF) analysis, and immunohistochemistry (IHC), immunoblotting, ELISA and biochemical assays with kits. The same assays were performed after combination treatment with Mdivi-1 (an inhibitor of mitophagy, i.p. 10 mg/kg·bw, twice a week for 12 w) or Mel (i.p. 10 mg/kg·bw, once a day for 12 w) under high-level exposure. Gly combined with Hwt (Gly-Hwt) significantly increased P16-P21-dependent PTE cell senescence, mitochondrial fission and oxidative stress, and activated PINK1-Parkin-mediated mitophagy, accompanied by defective autophagic flux at high doses but unaltered autophagic flux at low doses. Improved senescence occurred after Mdivi-1 administration, suggesting that mitophagy is involved in cellular senescence. Mel significantly decreased senescence induced by Gly-Hwt. Furthermore, PINK1-Parkin-dependent mitophagy and autophagic flux were markedly enhanced, and mitochondrial function was improved, as evidenced by reductions in mitochondrial fission and subsequent oxidative damage. Thus, Gly and Hwt synergistically promote PTE cell senescence through PINK1-Parkin-mediated mitophagy, and Mel exerts renoprotective effects by modulating mitophagy, suggesting therapeutic applications in ageing-related CINAC.

Coiled-coil-helix-coiled-coil-helix domain-containing 10 (CHCHD10) is a nuclear-encoded mitochondrial protein which is primarily mutated in the spectrum of familial and sporadic amyotrophic lateral sclerosis (ALS)–frontotemporal dementia (FTD). Endogenous CHCHD10 levels decline in the brains of ALS–FTD patients, and the CHCHD10S59L mutation in Drosophila induces dominant toxicity together with PTEN-induced kinase 1 (PINK1), a protein critical for the induction of mitophagy. However, whether and how CHCHD10 variants regulate mitophagy flux in the mammalian brain is unknown. Here, we demonstrate through in vivo and in vitro models, as well as human FTD brain tissue, that ALS/FTD-linked CHCHD10 mutations (R15L and S59L) impair mitophagy flux and mitochondrial Parkin recruitment, whereas wild-type CHCHD10 (CHCHD10WT) normally enhances these measures. Specifically, we show that CHCHD10R15L and CHCHD10S59L mutations reduce PINK1 levels by increasing PARL activity, whereas CHCHD10WT produces the opposite results through its stronger interaction with PARL, suppressing its activity. Importantly, we also demonstrate that FTD brains with TAR DNA-binding protein-43 (TDP-43) pathology demonstrate disruption of the PARL–PINK1 pathway and that experimentally impairing mitophagy promotes TDP-43 aggregation. Thus, we provide herein new insights into the regulation of mitophagy and TDP-43 aggregation in the mammalian brain through the CHCHD10–PARL–PINK1 pathway.

During the antiretroviral era, individuals living with HIV continue to experience milder forms of HIV-associated neurocognitive disorder (HAND). Viral proteins, including Tat, play a pivotal role in the observed alterations within the central nervous system (CNS), with mitochondrial dysfunction emerging as a prominent hallmark. As a result, our objective was to examine the expression of genes associated with mitophagy and mitochondrial biogenesis in the brain exposed to the HIV-1 Tat protein. We achieved this by performing bilateral stereotaxic injections of 100 ng of HIV-1 Tat into the hippocampus of Sprague–Dawley rats, followed by immunoneuromagnetic cell isolation. Subsequently, we assessed the gene expression of Ppargc1a, Pink1, and Sirt1-3 in neurons using RT-qPCR. Additionally, to understand the role of Tert in telomeric dysfunction, we quantified the activity and expression of Tert. Our results revealed that only Ppargc1a, Pink1, and mitochondrial Sirt3 were downregulated in response to the presence of HIV-1 Tat in hippocampal neurons. Interestingly, we observed a reduction in the activity of Tert in the experimental group, while mRNA levels remained relatively stable. These findings support the compelling evidence of dysregulation in both mitophagy and mitochondrial biogenesis in neurons exposed to HIV-1 Tat, which in turn induces telomeric dysfunction.

Mitochondrial dysregulation, such as mitochondrial complex I deficiency, increased oxidative stress, perturbation of mitochondrial dynamics and mitophagy, has long been implicated in the pathogenesis of PD. Initiating from the observation that mitochondrial toxins cause PD-like symptoms and mitochondrial DNA mutations are associated with increased risk of PD, many mutated genes linked to familial forms of PD, including PRKN, PINK1, DJ-1 and SNCA, have also been found to affect the mitochondrial features. Recent research has uncovered a much more complex involvement of mitochondria in PD. Disruption of mitochondrial quality control coupled with abnormal secretion of mitochondrial contents to dispose damaged organelles may play a role in the pathogenesis of PD. Furthermore, due to its bacterial ancestry, circulating mitochondrial DNAs can function as damage-associated molecular patterns eliciting inflammatory response. In this review, we summarize and discuss the connection between mitochondrial dysfunction and PD, highlighting the molecular triggers of the disease process, the intra- and extracellular roles of mitochondria in PD as well as the therapeutic potential of mitochondrial transplantation.

Parkin, the gene responsible for hereditary Parkinson’s disease (PD) called “Autosomal Recessive Juvenile Parkinsonism (AR-JP)” was discovered a quarter of a century ago. Owing to its huge gene structure and unique protein functions, parkin has become a subject of interest to those involved in PD research and researchers and clinicians in various fields and is being vigorously studied worldwide in relation to its nature and disease. The gene structure was registered under the gene name “parkin” in the GenBank in 1997. In 1998, deletion and point mutations in the parkin gene were reported, thereby demonstrating parkin is the causative gene for hereditary PD. Although 25 years have passed since the gene’s discovery and many researchers have worked tirelessly to elucidate the function of the Parkin protein and the mechanism of its role against neuronal cell death and pathogenesis remain unknown, which raises a major question concerning the current leading hypothesis. In this review, we present the results of related research on the parkin gene in chronological order and discuss unresolved problems concerning its function and pathology as well as new trends in the research conducted to solve them. The relationship between parkin and tumorigenesis has also been addressed from the perspective of Parkin’s redox molecule.

Background: Inflammatory pain, characterized by sustained nociceptive hypersensitivity, represents one of the most prevalent conditions in both daily life and clinical settings. Aucubin, a natural plant iridoid glycoside, possesses potent biological effects, encompassing anti-inflammatory, antioxidant, and neuroprotective properties. However, its impact on inflammatory pain remains unclear. The aim of this study is to investigate the therapeutic effects and underlying mechanism of aucubin in addressing inflammatory pain induced by complete Freund’s adjuvant (CFA). Methods: The CFA-induced inflammatory pain model was employed to assess whether aucubin exerts analgesic effects and its potential mechanisms. Behavioral tests evaluated mechanical and thermal hyperalgesia as well as anxiety-like behaviors in mice. The activation of spinal glial cells and the expression of pro-inflammatory cytokines were examined to evaluate neuroinflammation. Additionally, RNA sequencing was utilized for the identification of differentially expressed genes (DEGs). Molecular biology experiments were conducted to determine the levels of the PINK1 gene and autophagy-related genes, along with PINK1 distribution in neural cells. Furthermore, mitophagy induced by carbonyl cyanide m-chlorophenylhydrazone (CCCP) was employed to examine the roles of PINK1 and mitophagy in pain processing. Results: Aucubin significantly ameliorated pain and anxiety-like behaviors induced by CFA in mice and reduced spinal inflammation. RNA sequencing indicated PINK1 as a pivotal gene, and aucubin treatment led to a significant downregulation of PINK1 expression. Further GO and KEGG analyses suggested the involvement of mitochondrial function in the therapeutic regulation of aucubin. Western blotting revealed that aucubin markedly decreased PINK1, Parkin, and p62 levels while increasing LC3B expression. Immunofluorescence showed the predominant co-localization of PINK1 with neuronal cells. Moreover, CCCP-induced mitophagy alleviated mechanical and thermal hyperalgesia caused by CFA and reversed CFA-induced mitochondrial dysfunction. Conclusions: In summary, our data suggest that aucubin effectively alleviates CFA-induced inflammatory pain, potentially through triggering the PINK1 pathway, promoting mitophagy, and suppressing inflammation. These results provide a novel theoretical foundation for addressing the treatment of inflammatory pain.

Abstract Accumulation of impaired mitochondria and energy metabolism disorders are non-negligible features of both aging and age-related neurodegeneration, including Alzheimer’s disease (AD). A growing number of studies suggest that mitophagy disorders play an important role in AD occurrence and development. The interaction between mitophagy deficits and Aβ or Tau pathology may form a vicious cycle and cause neuronal damage and death. Elucidating the molecular mechanism of mitophagy and its role in AD may provide insights into the etiology and mechanisms of AD. Defective mitophagy is a potential target for AD prevention and treatment.

Abstract Background The loss of dopamine neurons in the substantia nigra, as well as other mostly catecholaminergic neurons, causes many of the motor symptoms that define Parkinson's disease. Parkinson's disease is commonly thought of as a movement disorder, the significant prevalence of psychiatric complications such as cognitive impairment, and psychosis suggests it should be considered a neuropsychiatric illness, and all behavioral complications are linked to growing disability and the medication. Main body Apart from the disease-induced abnormalities, there are several other side effects of the disease and also from the medication used to prevent the disease. This article focuses on the pathogenesis of Parkinson’s disease and also the behavioral abnormalities caused by the disease and its medication. The study's data were gathered by searching several review articles and research papers from a variety of sources, including Elsevier, PubMed, Research Gate, Journal of Pharmaceutical Science, etc., from the year 1985 to 2021. Parkinson's disease is a neurodegenerative disease caused by a variety of complex processes. It is responsible not just for motor symptoms, but also for a variety of behavioral symptoms that can arise as a result of the disease and/or medication. Conclusion Only symptomatic drugs are available; thus, finding treatments that directly address the disease mechanisms causing Parkinson’s disease is essential. To alleviate the disease's burden on patients and their families, better treatments for the neuropsychiatric repercussions of Parkinson's disease are required. Graphical Abstract

Abstract Background Oxidative stress mediated by hyperglycemia damages cell-reparative processes such as mitophagy. Down-regulation of mitophagy is considered to be a susceptible factor for diabetes mellitus (DM) and its complications. However, the role of mitophagy in DM-associated periodontitis has not been fully elucidated. Apoptosis of human gingival epithelial cells (hGECs) is one of the representative events of DM-associated periodontitis. Thus, this study aimed to investigate PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy activated in the process of high glucose (HG)-induced hGECs apoptosis. Methods For dose–response studies, hGECs were incubated in different concentrations of glucose (5.5, 15, 25, and 50 mmol/L) for 48 h. Then, hGECs were challenged with 25 mmol/L glucose for 12 h and 48 h, respectively. Apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL), caspase 9 and mitochondrial membrane potential (MMP). Subsequently, autophagy was evaluated by estimating P62, LC3 II mRNA levels, LC3 fluorescent puncta and LC3-II/I ratio. Meanwhile, the involvement of PINK1-mediated mitophagy was assessed by qRT-PCR, western blotting and immunofluorescence. Finally, hGECs were transfected with shPINK1 and analyzed by MMP, caspase 9 and annexin V-FITC apoptosis. Results The number of TUNEL-positive cells and caspase 9 protein were significantly increased in cells challenged with HG (25 mmol/L) for 48 h (HG 48 h). MMP was impaired both at HG 12 h and HG 48 h, but the degree of depolarization was more serious at HG 48 h. The autophagy improved as the amount of LC3 II increased and p62 decreased in HG 12 h. During this process, HG 12 h treatment induced PINK1-mediated mitophagy. PINK1 silencing with HG 12 h resulted in MMP depolarization and cell apoptosis. Conclusions These results suggested that loss of the PINK1 gene may cause mitochondrial dysfunction and increase sensitivity to HG-induced apoptosis of hGECs at the early stage. PINK1 mediated mitophagy attenuates early apoptosis of gingival epithelial cells induced by high glucose.

The pathophysiology of Alzheimer’s disease (AD) is multifactorial with characteristic extracellular accumulation of amyloid-beta (Aβ) and intraneuronal aggregation of hyperphosphorylated tau in the brain. Development of disease-modifying treatment for AD has been challenging. Recent studies suggest that deleterious alterations in neurovascular cells happens in parallel with Aβ accumulation, inducing tau pathology and necroptosis. Therefore, therapies targeting cellular Aβ and tau pathologies may provide a more effective strategy of disease intervention. Tetramethylpyrazine nitrone (TBN) is a nitrone derivative of tetramethylpyrazine, an active ingredient from Ligusticum wallichii Franchat (Chuanxiong). We previously showed that TBN is a potent scavenger of free radicals with multi-targeted neuroprotective effects in rat and monkey models of ischemic stroke. The present study aimed to investigate the anti-AD properties of TBN. We employed AD-related cellular model (N2a/APPswe) and transgenic mouse model (3×Tg-AD mouse) for mechanistic and behavioral studies. Our results showed that TBN markedly improved cognitive functions and reduced Aβ and hyperphosphorylated tau levels in mouse model. Further investigation of the underlying mechanisms revealed that TBN promoted non-amyloidogenic processing pathway of amyloid precursor protein (APP) in N2a/APPswe in vitro. Moreover, TBN preserved synapses from dendritic spine loss and upregulated synaptic protein expressions in 3×Tg-AD mice. Proteomic analysis of 3×Tg-AD mouse hippocampal and cortical tissues showed that TBN induced neuroprotective effects through modulating mitophagy, MAPK and mTOR pathways. In particular, TBN significantly upregulated PINK1, a key protein for mitochondrial homeostasis, implicating PINK1 as a potential therapeutic target for AD. In summary, TBN improved cognitive functions in AD-related mouse model, inhibited Aβ production and tau hyperphosphorylation, and rescued synaptic loss and neuronal damage. Multiple mechanisms underlie the anti-AD effects of TBN including the modulation of APP processing, mTOR signaling and PINK1-related mitophagy.

Mitophagy has distinct functions, which can lead to either protection or damage of tissues. Though current evidence indicated that NaF triggers mitophagy, the role and regulation of mitophagy in sodium fluoride (NaF)-induced liver injury still remain unclear. Therefore, we exployed the cell and mouse models and confirmed that NaF treatment activates mitophagy. Knocking down PTEN-induced putative kinase protein 1 (PINK1) expression attenuated mitophagy and increased the degree of mitochondrial impairment, oxidative stress, and apoptosis in NaF-treated HepG2 cells. In vivo experiments indicated that PINK1 deficiency weakened NaF-induced mitophagy. Moreover, PINK1-deficient mices aggravated NaF-induced hepatic mitochondrial injury, oxidative stress, and inflammation in livers, evidenced by the increased number of abnormal mitochondria, decreased adenosine triphosphate (ATP) and glutathione (GSH) levels, elevated reactive oxygen species (ROS) and malondialdehyde (MDA) content, enhanced hepatic macrophage infiltration and inflammatory cytokine levels. Notably, NaF exposure activated Nrf2 signaling both in vitro and in vivo. Nrf2 siRNA transfection blocked the upregulation of PINK1 expression and the induction of mitophagy in NaF-treated HepG2 cells. Also, ML385 (Nrf2 inhibitor) partially blocked the upregulation of PINK1 expression caused by NaF in mice livers. To sum up, the present study provided the demonstration that Nrf2/PINK1-mediated mitophagy activation offers a hepatoprotective effect by inhibiting NaF-induced mitochondrial dysfunction, oxidative stress, and inflammation.

Abstract Purpose Study of the effects and mechanisms of licorice in the treatment of ulcerative colitis (UC) from the perspective of mitochondrial autophagy. Methods BALB/C mice were induced with 3% dextran sodium sulfate to build an animal model of UC. After 7 days of modeling, different doses of licorice were administered for 7 days. Hematoxylin and eosin staining is used to detect pathological changes in the colon. Mitochondrial membrane potentials and reactive oxygen species (ROS) contents were detected by flow cytometry, and autophagy of mitochondria was observed by transmission electron microscopy. Determination of inflammatory cytokines by enzyme‐linked immunosorbent assay. The oxidizing factors are detected by the kits. Western blot analysis was used to detect expressions for nuclear factor called erythropoietin (Nrf2), pten‐induced protein kinase 1 (PINK1), Parkin, HO‐1, P62, and LC3. Results Licorice improved the pathological condition of UC mice, increasing the mitochondrial membrane potential and decreasing the ROS content. Promotes the emergence of autophagosomes and autophagosomes. The contents of interleukin (IL)‐1β, IL‐6, IL‐17, and tumor necrosis factor‐alpha were downregulated, the contents of superoxide dismutase and glutathione peroxidase were upregulated and the contents of malondialdehyde were downregulated. In addition, licorice promotes the expression of Nrf2, PINK1, Parkin, HO‐1, P62, and LC3. Conclusion Licorice was shown to reduce levels of inflammatory factors and oxidative stress in mice with UC, possibly by promoting mitochondrial autophagy through the activation of the Nrf2/PINK1 pathway.

Mitochondria play a multidimensional role in the function and the vitality of the neurological system. From the generation of neural stem cells to the maintenance of neurons and their ultimate demise, mitochondria play a critical role in regulating our neural pathways’ homeostasis, a task that is critical to our cognitive health and neurological well-being. Mitochondria provide energy via oxidative phosphorylation for the neurotransmission and generation of an action potential along the neuron’s axon. This paper will first review and examine the molecular subtleties of the mitochondria’s role in neurogenesis and neuron vitality, as well as outlining the impact of defective mitochondria in neural aging. The authors will then summarize neurodegenerative diseases related to either neurogenesis or homeostatic dysfunction. Because of the significant detriment neurodegenerative diseases have on the quality of life, it is essential to understand their etiology and ongoing molecular mechanics. The mitochondrial role in neurogenesis and neuron vitality is essential. Dissecting and understanding this organelle’s role in the genesis and homeostasis of neurons should assist in finding pharmaceutical targets for neurodegenerative diseases.

Hepatic ischemia/reperfusion (I/R) injury contributes to morbidity and mortality during liver resection or transplantation, with limited effective treatments available. Here, we investigated the potential benefits and underlying mechanisms of pterostilbene (Pt), a natural component of blueberries and grapes, in preventing hepatic I/R injury. Male C57BL/6 mice subjected to partial warm hepatic I/R and human hepatocyte cell line L02 cells exposed to anoxia/reoxygenation (A/R) were used as in vivo and in vitro models, respectively. Our findings showed that pretreatment with Pt ameliorated hepatic I/R injury by improving liver histology, decreasing hepatocyte apoptosis, and reducing plasma ALT and AST levels. Likewise, cell apoptosis, mitochondrial membrane dysfunction, and mitochondrial ROS overproduction in L02 cells triggered by the A/R challenge in vitro were reduced due to Pt administration. Mechanistically, Pt treatment efficiently enhanced mitophagy and upregulated PINK1, Parkin, and LC3B expression. Notably, the protective effect of Pt was largely abrogated after cells were transfected with PINK1 siRNA. Moreover, Pt pretreatment promoted hepatocyte proliferation and liver regeneration in the late phase of hepatic I/R. In conclusion, our findings provide evidence that Pt exerts hepatoprotective effects in hepatic I/R injury by upregulating PINK1-mediated mitophagy.

Abstract Background Parkinson’s disease (PD) is a multifactorial neurodegenerative disorder marked by the death of nigrostriatal dopaminergic neurons in response to the compounding effects of oxidative stress, mitochondrial dysfunction and protein aggregation. Transgenic Drosophila models have been used extensively to decipher the underlying genetic interactions that exacerbate neural health in PD. Autosomal recessive forms of the disease have been linked to mutations in the serine/threonine kinase PINK1(PTEN-Induced Putative Kinase 1) and E3 ligase Parkin, which function in an axis that is conserved in flies. This review aims to probe the current understanding of PD pathogenesis via the PINK1/Parkin axis while underscoring the importance of several molecular and pharmacologic rescues brought to light through studies in Drosophila. Main body Mutations in PINK1 and Parkin have been shown to affect the axonal transport of mitochondria within dopaminergic neurons and perturb the balance between mitochondrial fusion/fission resulting in abnormal mitochondrial morphology. As per studies in flies, ectopic expression of Fwd kinase and Atg-1 to promote fission and mitophagy while suppressing fusion via MUL1 E3 ligase may aid to halt mitochondrial aggregation and prolong the survival of dopaminergic neurons. Furthermore, upregulation of Hsp70/Hsp90 chaperone systems (Trap1, CHIP) to target misfolded mitochondrial respiratory complexes may help to preserve their bioenergetic capacity. Accumulation of reactive oxygen species as a consequence of respiratory complex dysfunction or antioxidant enzyme deficiency further escalates neural death by inducing apoptosis, lipid peroxidation and DNA damage. Fly studies have reported the induction of canonical Wnt signalling to enhance the activity of transcriptional co-activators (PGC1α, FOXO) which induce the expression of antioxidant enzymes. Enhancing the clearance of free radicals via uncoupling proteins (UCP4) has also been reported to ameliorate oxidative stress-induced cell death in PINK1/Parkin mutants. Conclusion While these novel mechanisms require validation through mammalian studies, they offer several explanations for the factors propagating dopaminergic death as well as promising insights into the therapeutic importance of transgenic fly models in PD.

Abstract Background PTEN-induced kinase 1 (PINK1) is a serine/threonine-protein kinase in mitochondria that is critical for mitochondrial quality control. PINK1 triggers mitophagy, a selective autophagy of mitochondria, and is involved in mitochondrial regeneration. Although increments of mitochondrial biogenesis and activity are known to be crucial during differentiation, data regarding the specific role of PINK1 in osteogenic maturation and bone remodeling are limited. Methods We adopted an ovariectomy model in female wildtype and Pink1 −/− mice. Ovariectomized mice were analyzed using micro-CT, H&E staining, Masson’s trichrome staining. RT-PCR, western blot, immunofluorescence, alkaline phosphatase, and alizarin red staining were performed to assess the expression of PINK1 and osteogenic markers in silencing of PINK1 MC3T3-E1 cells. Clinical relevance of PINK1 expression levels was determined via qRT-PCR analysis in normal and osteoporosis patients. Results A significant decrease in bone mass and collagen deposition was observed in the femurs of Pink1 −/− mice after ovariectomy. Ex vivo, differentiation of osteoblasts was inhibited upon Pink1 downregulation, accompanied by impaired mitochondrial homeostasis, increased mitochondrial reactive oxygen species production, and defects in mitochondrial calcium handling. Furthermore, PINK1 expression was reduced in bones from patients with osteoporosis, which supports the practical role of PINK1 in human bone disease. Conclusions In this study, we demonstrated that activation of PINK1 is a requisite in osteoblasts during differentiation, which is related to mitochondrial quality control and low reactive oxygen species production. Enhancing PINK1 activity might be a possible treatment target in bone diseases as it can promote a healthy pool of functional mitochondria in osteoblasts.