Cellular mitophagy: Mechanism, roles in diseases and small molecule pharmacological regulation

PPM1D ameliorates Alzheimer's disease by promoting mitophagy

Mitochondrial autophagy (mitophagy) plays an essential role in the maintenance of mitochondrial homeostasis. Defective mitophagy triggered by amyloid beta (Aβ) is linked to neuronal deterioration and neurodegeneration in Alzheimer's disease (AD). However, the molecular mechanism underlying the defective mitophagy in AD is still not fully illustrated. Protein phosphatase Mn2+/Mg2+-dependent 1D (PPM1D) triggers autophagy in mouse embryonic fibroblasts. Downregulated PPM1D was shown in the hippocampus of APP/PS1 mice. This study aims to investigate the role of PPM1D in the progression of AD. Here, APP/PS1 mice were used to mimic AD, and rAAV2 vectors expressing PPM1D were injected into the bilateral hippocampus. In vitro, the mouse hippocampal neuron cell line HT22 was stimulated by Aβ1-42 to trigger neuronal damage. High PPM1D expression alleviated the impairments of spatial cognition and memory in APP/PS1 mice. Additionally, PPM1D enhanced autophagosome formation, lysosomal degradation of impaired mitochondria, amyloid plaque deposition, and neuronal degeneration and apoptosis in the hippocampus of APP/PS1 mice. Similar effects of PPM1D on neuronal apoptosis and mitophagy were observed in Aβ1-42-treated HT22 cells, and the effects could be reversed by the mitophagy inhibitor cyclosporine A. In conclusion, PPM1D facilitates mitophagy to inhibit the progression of AD-like disease. Taken together, the present work uncovers defective mitophagy in AD may be associated with down-regulated PPM1D, and PPM1D may be a potential therapeutic target for AD treatment.

Novel pH-responsive lipid nanoparticles deliver UA-mediated mitophagy and ferroptosis for osteoarthritis treatment

Synovial inflammation plays a crucial role in osteoarthritis (OA) development, leading to chronic inflammation and cartilage destruction. Although targeting synovitis can alleviate OA, clinical outcomes have been disappointing due to poor drug targeting and joint cavity heterogeneity. This study presents pH-responsive lipid nanoparticles (LNPs@UA), loaded with Urolithin A (UA), as a potential OA treatment. LNPs@UA showed uniform particle size, low zeta potential, and effective mitochondria-targeting and pH-responsive capabilities. In vitro, LNPs@UA reduced reactive oxygen species (ROS), pro-inflammatory factors (IL-1β, IL-6, TNF-α), and promoted M2 macrophage polarization. It improved mitochondrial structure, enhanced autophagy, and inhibited ferroptosis. In vivo, LNPs@UA alleviated OA progression in an ACLT-induced OA mouse model. Transcriptomic analysis revealed inhibition of NF-κB signaling and activation of repair pathways. These results suggest LNPs@UA could offer a promising therapeutic approach for OA.

Crosstalk between autophagy and other forms of programmed cell death

Cell death occurs continuously throughout individual development. By removing damaged or senescent cells, cell death not only facilitates morphogenesis during the developmental process, but also contributes to maintaining homeostasis after birth. In addition, cell death reduces the spread of pathogens by eliminating infected cells. Cell death is categorized into two main forms: necrosis and programmed cell death. Programmed cell death encompasses several types, including autophagy, pyroptosis, apoptosis, necroptosis, ferroptosis, and PANoptosis. Autophagy, a mechanism of cell death that maintains cellular equilibrium via the breakdown and reutilization of proteins and organelles, is implicated in regulating almost all forms of cell death in pathological contexts. Notably, necroptosis, ferroptosis, and PANoptosis are directly classified as autophagy-mediated cell death. Therefore, regulating autophagy presents a therapeutic approach for treating diseases such as inflammation and tumors that arise from abnormalities in other forms of programmed cell death. This review focuses on the crosstalk between autophagy and other programmed cell death modalities, providing new perspectives for clinical interventions in inflammatory and neoplastic diseases.

Bioactive phosphorus dendrimers deliver protein/drug to tackle osteoarthritis via cooperative macrophage reprogramming

Reprogramming imbalanced synovial macrophages and shaping an immune microenvironment conducive to bone and cartilage growth is crucial for efficient tackling of osteoarthritis (OA). Herein, we present a co-delivery nanosystem based on generation 2 (G2) hydroxyl-terminated bioactive phosphorus dendrimers (G2-OH24) that were loaded with both catalase (CAT) and quercetin (Que). The created G2-OH24/CAT@Que complexes exhibit a uniformly distributed spherical morphology with a size of 138.8 nm, possess robust stability, and induce macrophage reprogramming toward anti-inflammatory M2 phenotype polarization and antioxidation through cooperative CAT-catalyzed oxygen generation, Que-mediated mitochondrial homeostasis restoration, and inherent immunomodulatory activity of dendrimer. Such macrophage reprogramming leads to chondrocyte apoptosis inhibition and osteogenic differentiation of bone mesenchymal stem cells. Administration of G2-OH24/CAT@Que to an OA mouse model results in attenuation of pathological features such as cartilage degeneration, bone erosion, and synovitis through oxidative stress alleviation and inflammatory factor downregulation in inflamed joints. Excitingly, the G2-OH24/CAT@Que also polarized macrophages in adherent effusion monocytes (AEMs) extracted from joint cavity effusions of OA patients to M2 phenotype and downregulated reactive oxygen species levels in AEMs. This study suggests a promising nanomedicine formulation of phosphorus dendrimer-based co-delivery system to effectively tackle OA through the benefits of full-active ingredients of dendrimer, drug, and protein.

The effect of mitochondrial-associated endoplasmic reticulum membranes (MAMs) modulation: New insights into therapeutic targets for depression

Depression is a prevalent mental disorder with high morbidity and mortality and its pathogenesis remains exactly unclarified. However, mitochondria and endoplasmic reticulum (ER) are two highly dynamic organelles that perform an indispensable role in the development of depression. Mitochondrial dysfunction and ER stress are recognized as vital pathological hallmarks in depression. The changes of intracellular activities such as mitochondrial dynamics, mitophagy, energy metabolism and ER stress are closely correlated with the progression of depression. Moreover, organelles interactions are conducive to homeostasis and cellular functions, and mitochondrial-associated endoplasmic reticulum membranes (MAMs) serve as signaling hubs of the two organelles and the coupling of the pathological progression. The main roles of MAMs are involved in metabolism, signal transduction, lipid transport, and maintenance of its structure and function. At present, accumulating studies elucidated that MAMs have gradually become a novel therapeutic target in treatment of depression. In the review, we focus on influence of mitochondria dysfunction and ER stress on depression. Furthermore, we discuss the underlying role of MAMs in depression and highlight natural products targeting MAMs as potential antidepressants to treat depression.

Mechanism of Nano-Microplastics Exposure-Induced Myocardial Fibrosis: DKK3-Mediated Mitophagy Dysfunction and Pyroptosis

Nano-microplastics (NMPs), as environmental pollutants, are widely present in nature and pose potential threats to biological health. This study aims to investigate the mechanisms by which NMPs inhibit mitophagy through the suppression of dickkopf-related protein 3 (DKK3) expression, leading to NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome-mediated cardiomyocyte pyroptosis and promoting myocardial fibrosis. Healthy adult male C57BL/6 mice were administered NMP solution via gavage, and their cardiac function was monitored. The results showed that NMP exposure significantly reduced left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) and increased the extent of myocardial fibrosis. Transcriptome sequencing identified 14 differentially expressed genes (DEGs), including MYL7. Using the random forest algorithm and functional enrichment analysis, DKK3 was identified as a key gene. In Vitro experiments further confirmed that NMPs downregulate DKK3 expression, thereby inhibiting mitophagy and promoting cardiomyocyte pyroptosis. This study elucidates the molecular mechanisms by which NMPs induce myocardial fibrosis and provides new theoretical bases and molecular targets for the diagnosis and treatment of heart diseases.

The potential of natural herbal plants in the treatment and prevention of non-small cell lung cancer: An encounter between ferroptosis and mitophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese herbal medicine constitutes a substantial cultural and scientific resource for the Chinese nation, attracting considerable scholarly interest due to its intrinsic characteristics of "multi-component, multi-target, and multi-pathway" interactions. Simultaneously, it aligns accurately with the intricate and continuously evolving progression of non-small cell lung cancer (NSCLC). Furthermore, contemporary pharmacological studies indicate that natural herbaceous plants and their bioactive compounds exhibit a diverse array of biological activities, including antioxidant, anti-inflammatory, and anti-tumor effects, among others. Additionally, these substances have been demonstrated to possess a degree of safety, particularly in terms of exhibiting comparatively lower levels of toxicity to the liver and kidneys when contrasted with conventional Western medicine. Thus, the development of herbal plants, which includes both single herbs and composite formulations, as well as their bioactive constituents, through the targeted regulation of ferroptosis and mitophagy, presents substantial potential and instills considerable hope for individuals diagnosed with NSCLC.

AIM OF THE REVIEW

This review aims to conduct a critical analysis of the ethnopharmacological applications of natural herbaceous plants in relation to ferroptosis and mitophagy in NSCLC. The objective is to evaluate the potential advantages of prioritizing specific phytochemical constituents found in these plants, which may serve as novel therapeutic candidates informed by ethnobotanical knowledge. Additionally, this study seeks to enhance the current pharmacological applications of natural herbaceous plants.

METHODS

An investigation into natural herbal remedies for NSCLC was conducted, with a particular emphasis on the ferroptosis and mitophagy pathways. This study utilized traditional medical texts and ethnomedicinal literature as primary sources. Furthermore, relevant information related to ethnobotany, phytochemistry, and pharmacology is obtained from online databases, including PubMed and the China National Knowledge Infrastructure (CNKI), among others. "Traditional Chinese medicine compound preparations", "single herb extracts", "active compounds", "NSCLC", "ferroptosis", and "mitophagy" were used as keywords when searching the databases. Consequently, pertinent articles published in recent years were collected and analyzed.

RESULTS

Given the complex etiology of NSCLC, treatment strategies that concentrate exclusively on ferroptosis or mitophagy often demonstrate limitations. In this regard, the utilization of herbal plants offers unique benefits in the management of NSCLC. The rationale can be summarized within the following two dimensions: Firstly, due to the molecular mechanisms of ferroptosis and mitophagy involving multiple signaling pathways (including PINK1/Parkin, HMGB1, system Xc-/GPX4/GSH, FSP1/CoQ10/NAD (P) H, and so on), sometimes drugs with a single target are difficult to involve multiple pathways. Fortunately, there is an expanding body of evidence suggesting that various herbaceous plants and their bioactive compounds can affect multiple biological targets. Moreover, these compounds seem to interact with several targets associated with ferroptosis and mitophagy in NSCLC (such as NIX, BNIP3, FUNDC1, GPX4, FSP1, P53, Nrf2, LncRNA, and so on). Secondly, Herbaceous plants and their bioactive compounds have been shown to possess a favorable safety profile, particularly with respect to reduced hepatotoxicity and nephrotoxicity in comparison to conventional Western medicine. For example, Numerous compound formulations, such as Fangji Huangqi decoction, Mufangji decoction, Qiyu Sanlong decoction, and Fuzheng Kangai decoction, have been employed in China for millennia, and their clinical efficacy appears to be quite promising. Notably, In recent years, numerous researchers have sought to isolate active constituents from clinically effective compound formulations through the application of chemical methodologies. This endeavor has been driven by the necessity to tackle challenges related to complex ingredient compositions and sophisticated processing. These active compounds have been employed in cellular and animal studies to elucidate the molecular mechanisms underlying these formulations.

CONCLUSIONS

The Asian region has a long-standing historical tradition of employing natural herbaceous plants for traditional medicinal purposes. Phytochemical and pharmacological studies have shown that various compound preparations derived from traditional Chinese medicine, along with individual herb extracts and their active constituents, display a range of bioactive effects. These effects encompass anti-tumor, anti-inflammatory, antibacterial, and antioxidant properties, among others. Numerous traditional compound formulations originating from China have emerged as promising candidates for the development of pharmacological agents targeting NSCLC. It is noteworthy that a variety of compound formulations aimed at the ferroptosis and mitophagy pathways, which demonstrate unique therapeutic effects on NSCLC, are presently under extensive investigation by an increasing number of researchers. Therefore, it is imperative to consider in vitro mechanistic studies, in vivo pharmacological evaluations, and assessments of clinical efficacy. Furthermore, it is essential to conduct a comprehensive assessment of plant resources, implement quality control measures, and engage in toxicological research to ensure that the data is appropriate for further examination.

Energy Metabolism and Brain Aging: Strategies to Delay Neuronal Degeneration

Aging is characterized by a gradual decline in physiological functions, with brain aging being a major risk factor for numerous neurodegenerative diseases. Given the brain's high energy demands, maintaining an adequate ATP supply is crucial for its proper function. However, with advancing age, mitochondria dysfunction and a deteriorating energy metabolism lead to reduced overall energy production and impaired mitochondrial quality control (MQC). As a result, promoting healthy aging has become a key focus in contemporary research. This review examines the relationship between energy metabolism and brain aging, highlighting the connection between MQC and energy metabolism, and proposes strategies to delay brain aging by targeting energy metabolism.

OGA promotes human dental pulp stem cell senescence and inhibits mitophagy by inhibition of O-GlcNAcylation of KLF2

BACKGROUND

Dental pulp stem cells (DPSCs) aging impedes its application in tooth regeneration techniques, involving abnormal mitophagy. O-GlcNAcylation is a post-translational modification that regulates various cellular processes. Here, we aimed to investigate the role of O-GlcNAcylation in mitophagy and senescence.

METHODS

DPSCs were cultured and passaged in vitro, and the 7th (p7) and 15th (p15) generation cells were collected. OGA and KLF2 were knocked down in p15 cells. Cell senescence was evaluated using senescence associated β-galactosidase staining, enzyme-linked immunosorbent assay, and western blotting; mitophagy was evaluated using western blotting. The regulation of OGA on the O-GlcNAcylation of KLF2 was analyzed using immunoprecipitation and western blotting.

RESULTS

The results showed that p15 cells were more senescent than p7 cells and had poor mitophagy, with the higher expression of OGA. Knockdown of OGA inhibited senescence and promoted mitophagy in DPSCs. Moreover, silencing of KLF2 reversed the effects on senescence and mitophagy mediated by OGA knockdown. Additionally, OGA suppressed the O-GlcNAcylation of KLF2 at S177 site and thus reduced its stability.

CONCLUSION

Silencing of OGA promotes mitophagy and inhibits DPSC senescence by promoting the O-GlcNAcylation of KLF2, suggesting a novel mechanism underlying DPSC senescence.

Mitophagy in Brain Injuries: Mechanisms, Roles, and Therapeutic Potential

Mitophagy is an intracellular degradation pathway crucial for clearing damaged or dysfunctional mitochondria, thereby maintaining cellular homeostasis and responding to various brain injuries. By promptly removing damaged mitochondria, mitophagy protects cells from further harm and support cellular repair and recovery after injury. In different types of brain injury, mitophagy plays complex and critical roles, from regulating the balance between cell death and survival to influencing neurological recovery. This review aims to deeply explore the role and mechanism of mitophagy in the context of brain injuries and uncover how mitophagy regulates the brain response to injury and its potential therapeutic significance. It emphasizes mitophagy's potential in treating brain injuries, including reducing cell damage, promoting cell recovery, and improving neurological function, thus opening new perspectives and directions for future research and clinical applications.

Mitochondria in cancer: a comprehensive review, bibliometric analysis, and future perspectives

INTRODUCTION

Mitochondria are essential organelles for many aspects of cellular homeostasis. They play an indispensable role in the development and progression of diseases, particularly cancer which is a major cause of death worldwide. We analyzed the scientific research output on mitochondria and cancer via PubMed and Web of Science over the period 1990-2023.

METHODS

Bibliometric analysis was performed by extracting data linking mitochondria to cancer pathogenesis over the period 1990-2023 from the PubMed database which has a precise and specific search engine. Only articles and reviews were considered. Since PubMed does not support analyses by countries or institutions, we utilized InCites, an analytical tool developed and marketed by Clarivate Analytics. We also used the VOSviewer software developed by the Centre for Science and Technology Studies (Bibliometric Department of Leiden University, Leiden, Netherlands), which enables us to graphically represent links between countries, authors or keywords in cluster form. Finally, we used iCite, a tool developed by the NIH (USA) to access a dashboard of bibliometrics for papers associated with a portfolio. This module can therefore be used to measure whether the research carried out is still basic, translational or clinical.

RESULTS

In total, 169,555 publications were identified in PubMed relating to 'mitochondria', of which 34,949 (20.61%) concerned 'mitochondria' and 'dysfunction' and 22,406 (13.21%) regarded 'mitochondria' and 'cancer'. Hence, not all mitochondrial dysfunctions may lead to cancer or enhance its progression. Qualitatively, the disciplines of journals were classified into 166 categories among which cancer specialty accounts for only 4.7% of publications. Quantitatively, our analysis showed that cancer/neoplasms in the liver (2569 articles) were placed in the first position. USA occupied the first position among countries contributing the highest number of publications (5695 articles), whereas Egypt came in the thirty-eight position with 84 publications (0.46%). Importantly, USA is the first-ranked country having both the top 1% and 10% impact indicators with 207 and 1459 articles, respectively. By crossing the query 'liver neoplasms' (155,678) with the query 'mitochondria' (169,555), we identified 1336 articles in PubMed over the study period. Among these publications, research areas were classified into 65 categories with the highest percentage of documents included in biochemistry and molecular biology (28.92%), followed by oncology (23.31%).

CONCLUSIONS

This study underscores the crucial yet underrepresented role of mitochondria in cancer research. Despite their significance in cancer pathogenesis, the proportion of related publications remains relatively low. Our findings highlight the need for further research to deepen our understanding of mitochondrial mechanisms in cancer, which could pave the way for new therapeutic strategies.

Graphene Oxide Nanosheets Induce Mitochondrial Toxicity in Human Ovarian Granulosa Cells: Implications for Female Reproductive Health

Purpose

Graphene oxide (GO) has promising biomedical applications, but its potential toxicity to the female reproductive system is underexplored. This study investigates the short-term effects of a single dose of GO nanosheets on human ovarian granulosa cells, focusing on mitochondrial damage.

Materials and Methods

First, cell viability was detected by CCK-8 and apoptosis was detected by flow cytometry to assess the cytotoxicity of GO on KGN. Second, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and mitochondrial morphology were observed by confocal microscopy, mitochondrial and sub-mitochondrial structure by transmission electron microscopy (TEM), quantitative analysis of ATP and mitochondrial complex I enzyme activity by luminosity value and autophagy by flow cytometry to assess the mitochondrial toxicity of GO on KGN cells.

Results

The 72h half-maximum effective concentration (EC50) value of GO was determined to be 29.73 μg/mL. GO induced cell death in a dose-dependent manner, with significant effects on cell viability even at low doses (1 μg/mL). Exposure to low GO concentrations resulted in abnormal mitochondrial morphology and function, including mitochondrial breakage, membrane damage, reduced mitochondrial cristae, enhanced autophagy, decreased ATP production, decreased MMP, and decreased enzymatic activity of mitochondrial complex I. Mitochondrial function returned to normal levels on day 7 after KGN cells left the GO-exposed environment.

Conclusion

This study demonstrates that short-term exposure to low-dose GO causes mitochondrial damage in human ovarian granulosa cells, highlighting the need for further research on the safety of GO, particularly regarding its potential effects on reproductive health. However, GO-induced transient mitochondrial damage is highly likely to negatively affect ovarian reserve function, which needs to be further verified in animal models.

The effective-compound compatibility of JHF inhibits fibroblast activation in pulmonary fibrosis by enhancing PINK1/PARK2-mediated mitophagy

This work aimed to elucidate the anti-PF mechanism of ECC-JHF.The effects of ECC-JHF on lung fibrosis and fibroblast activation were investigated by establishing a BLM-induced PF rat model and a transforming growth factor-beta (TGF-β)-induced fibroblast activation model. Furthermore, the effects of ECC-JHF on Nrf2 signaling and mitophagy were explored both in vivo and in vitro. In the PF model rats, ECC-JHF mitigated pathological damage, reduced collagen deposition, decreased levels of malondialdehyde (MDA) and P62, and increased levels of total superoxide dismutase (T-SOD) as well as the expression of Nrf2, HO-1, PINK1, PARK2, and LC3B in lung tissues. These results suggest that the anti-PF mechanism of ECC-JHF may be associated with the inhibition of oxidative stress and the enhancement of mitophagy. The medium dose of ECC-JHF and pirfenidone were similar in improving pulmonary fibrosis in rats. In the TGF-β-induced lung fibroblast activation, ECC-JHF inhibited fibroblast activation by downregulating the levels of fibronectin, alpha-smooth muscle actin (α-SMA), and collagen I. Additionally, ECC-JHF upregulated the level of Nrf2 and its target proteins, including HO-1 and NQO1, as well as mitophagy-related proteins PINK1, PARK2, and LC3B. This led to an increase in the co-localization of TOM20 and LC3, thereby enhancing mitochondrial autophagy. The application of Nrf2 siRNA and Nrf2 inhibitors significantly diminished the effects of ECC-JHF on Nrf2 signaling, PINK1/PARK2-mediated mitophagy, and fibroblast activation. ECC-JHF exerts a protective effect against PF by suppressing fibroblast activation through the upregulation of Nrf2 and PINK1/PARK2-mediated mitophagy, it provides a new target and strategy for the treatment of pulmonary fibrosis.

TCE-mediated neuroprotection against rotenone-induced dopaminergic neuronal death in PD mice: insights into the Nrf-2/PINK1/Parkin-mitophagy pathway

Oxidative stress-induced mitochondrial dysfunction is implicated in the pathogenesis of Parkinson's disease (PD). In a previous study, we reported that an extract of T. cordifolia (TCE) possessed antioxidant and anti-apoptotic properties that improved mitochondrial function against rotenone-induced neurotoxicity. However, the underlying molecular mechanism remains unclear. In this study, we found that rotenone (ROT)-induced PD mice exhibited mitochondrial abnormalities, including defective mitophagy, mitochondrial reactive oxygen species (ROS) overexpression, and mitochondrial fragmentation, accompanied by reduced expression of Pink1 and Parkin and increased apoptosis. These changes were partially reversed following oral administration of TCE. Moreover, TCE restored the activity and translocation of NF-E2-related factor 2 (Nrf2) and upregulated the expression of antioxidant enzymes (SOD1, SOD2, GSH, and GSSH). Interestingly, ROT also activates mitophagy. Our results suggest that ROT toxicity can cause neuronal cell death through mitophagy-mediated signaling in PD mice. However, TCE reversed this activity by inhibiting autophagic protein (LC3B-II/LC3B-I) activation and increasing specific mitochondrial proteins (TOM20, Pink1, and Parkin). Our findings indicated that TCE provides neuroprotection against rotenone-induced toxicity in PD mice by stimulating endogenous antioxidant enzymes and inhibiting ROT-induced oxidative stress by potentiating the Nrf-2/Pink1/Parkin-mediated survival mechanism.

Marine-Derived Bioactive Compounds: A Promising Strategy for Ameliorating Skeletal Muscle Dysfunction in COPD

Chronic obstructive pulmonary disease (COPD) is frequently accompanied by skeletal muscle dysfunction, a critical and severe extrapulmonary complication. This dysfunction contributes to reduced exercise capacity, increased frequency of acute exacerbations, and elevated mortality, serving as an independent risk factor for poor prognosis in COPD patients. Owing to the unique physicochemical conditions of the marine environment, marine-derived bioactive compounds exhibit potent anti-inflammatory and antioxidant properties, demonstrating therapeutic potential for ameliorating COPD skeletal muscle dysfunction. This review summarizes marine-derived bioactive compounds with promising efficacy against skeletal muscle dysfunction in COPD, including polysaccharides, lipids, polyphenols, peptides, and carotenoids. The discussed compounds have shown bioactivities in promoting skeletal muscle health and suppressing muscle atrophy, thereby providing potential strategies for the prevention and treatment of COPD skeletal muscle dysfunction. These findings may expand the therapeutic strategies for managing COPD skeletal muscle dysfunction.

Elucidating the Molecular Mechanisms of Hederagenin-Regulated Mitophagy in Cervical Cancer SiHa Cells through an Integrative Approach Combining Proteomics and Advanced Network Association Algorithm

Hederagenin (Hed), a natural triterpenoid, exhibits antitumor potential in cervical cancer. The present study was designed to explore Hed's regulatory mechanisms on mitophagy in SiHa cervical cancer cells, employing tandem mass tag (TMT) proteomics and an advanced network association algorithm (NAA). Our findings revealed that Hed decreased SiHa cell viability, induced apoptosis, and altered mitochondrial membrane potential. Notably, Hed inhibited mitophagic flux under both normoxic and hypoxic conditions. Through TMT proteomics analysis and innovative NAA, we identified a close association between the HIF-1 signaling pathway and mitophagy. Network analysis further suggested that Hed acts on a target network centered on SRC, STAT3, AKT1, and HIF1A. Western blot analysis confirmed the expression and phosphorylation status of these targets in response to Hed. This study elucidates the molecular mechanisms underlying Hed's regulation of mitophagy in SiHa cells, offering novel insights and potential therapeutic targets for cervical cancer treatment.

tsRNA-12391-Modified Adipose Mesenchymal Stem Cell-Derived Exosomes Mitigate Cartilage Degeneration in Osteoarthritis by Enhancing Mitophagy

Osteoarthritis (OA) is a cartilage-degenerative joint disease. Mitophagy impacts articular cartilage damage. tRNA-derived small RNAs (tsRNAs) are one of the contents of adipose mesenchymal stem cell (AMSC)-derived exosomes (AMSC-exos) and are involved in disease progression. However, whether tsRNAs regulate mitophagy and whether tsRNA-modified AMSC-exos improve OA via mitophagy remain unclear. We performed small RNA sequencing to identify OA-related tsRNAs, which were then loaded into AMSC-exos, exploring the function and mechanisms related to mitophagy in vitro and in vivo. Overall, 53 differentially expressed tsRNAs (DEtsRNAs) were identified between OA and normal cartilage tissues, among which 42 DEtsRNAs, including tsRNA-12391, were downregulated in the OA group. Target genes of tsRNA-12391 mainly participated in mitophagy-related pathways such as Rap1 signaling pathway. Compared to the control group, tsRNA-12391 mimics significantly promoted mitophagy, as shown by the upregulated expression of PINK1 and LC3 and the co-localization of Mito-Tracker Green and PINK1. Furthermore, tsRNA-12391 mimics effectively enhanced chondrogenesis in chondrocytes, as demonstrated by the elevated expression of collagen II and ACAN. AMSC-exos with tsRNA-12391 overexpression also facilitated mitophagy and chondrogenesis in vitro and in vivo. Mechanistically, tsRNA-12391 bound to ATAD3A restricted ATAD31 from degrading PINK1, leading to PINK1 accumulation. ATAD31 overexpression reversed the effects of tsRNA-12391 mimics on mitophagy and chondrogenesis. AMSC-exos loaded with tsRNA-12391 promoted mitophagy and chondrogenesis by interacting with ATAD31; this may be a novel therapeutic strategy for OA.

The intricate ballet of inflammation and autophagy: Insights from Mycoplasma gallisepticum-infected HD11 cells

OBJECTIVES

Mycoplasma gallisepticum (M. gallisepticum) infection often leads to inflammatory damage and immunosuppression. Macrophages play a crucial role as the primary immune defense in chickens, with their inflammatory response and autophagy levels critical. This study aimed to explore the relationship between NLRP3 inflammasome and autophagy in HD11 cells within 12 h after M. gallisepticum infection.

METHODS

To investigate this, the HD11 cell model of M. gallisepticum infection was established using the CCK8 (Cell Counting Kit-8) method in this study. The study observed changes in M. gallisepticum-induced inflammation, oxidative stress, and autophagy levels through various methods including transmission electron microscopy (TEM), RT-qPCR, ELISA (enzyme linked immunosorbent assay), 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), JC-1 and Western blot.

RESULTS

TEM revealed that the nuclear membrane was damaged, the number of damaged mitochondria increased, and autophagosomes were detected at 4 and 8 h after M. gallisepticum infection. ELISA and RT-qPCR results indicated that M. gallisepticum induced oxidative stress and inflammation damage. Fluorescence analysis demonstrated an increase in intracellular reactive oxygen species (ROS) content and a continuous decrease in mitochondrial membrane potential (MMP) post-M. gallisepticum infection. Additionally, the NF-κB/NLRP3 signaling pathway remained consistently activated during M. gallisepticum infection. After M. gallisepticum infection, autophagy levels decreased significantly at 1 and 12 h, but increased significantly at 4 and 8 h.

CONCLUSIONS

M. gallisepticum infection triggers the activation of the NLRP3 inflammasome in HD11 cells, leading to inflammatory damage. Additionally, it causes fluctuations in autophagy levels, characterized by a wavy pattern of decrease, increase, and subsequent decrease.

Pharmacological modulation of mitochondrial function as novel strategies for treating intestinal inflammatory diseases and colorectal cancer

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal disease, and has become a major global health issue. Individuals with IBD face an elevated risk of developing colorectal cancer (CRC), and recent studies have indicated that mitochondrial dysfunction plays a pivotal role in the pathogenesis of both IBD and CRC. This review covers the pathogenesis of IBD and CRC, focusing on mitochondrial dysfunction, and explores pharmacological targets and strategies for addressing both conditions by modulating mitochondrial function. Additionally, recent advancements in the pharmacological modulation of mitochondrial dysfunction for treating IBD and CRC, encompassing mitochondrial damage, release of mitochondrial DNA (mtDNA), and impairment of mitophagy, are thoroughly summarized. The review also provides a systematic overview of natural compounds (such as flavonoids, alkaloids, and diterpenoids), Chinese medicines, and intestinal microbiota, which can alleviate IBD and attenuate the progression of CRC by modulating mitochondrial function. In the future, it will be imperative to develop more practical methodologies for real-time monitoring and accurate detection of mitochondrial function, which will greatly aid scientists in identifying more effective agents for treating IBD and CRC through modulation of mitochondrial function.

Identification and validation of biomarkers related to mitophagy in chronic obstructive pulmonary disease

Mitophagy plays significant roles in chronic obstructive pulmonary disease (COPD). The present study aimed to screen and validate mitophagy‑related genes in COPD by using bioinformatic analysis and experimental validation. The original data were downloaded from Gene Expression Omnibus datasets and 29 mitophagy‑related genes sets were acquired from the Molecular Signatures Database. The differentially expressed mitophagy‑related genes (DEMRGs) were screened using the Wilcoxon test. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were conducted for the identification of DEMRGs. In addition, clustering analysis was used to assess the differential expression characteristics of DEMRGs in patients with COPD. Least absolute shrinkage and selection operator (LASSO) regression analysis was performed to identify signature genes with COPD diagnostic significance; these genes were validated using the test dataset. In addition, the degree of infiltration of 28 immune cells in COPD and control samples was assessed. Finally, cigarette smoke extract (CSE)‑treated bronchial epithelial cells were employed to verify the role of signature genes in regulating mitophagy in vitro using molecular biology approaches. A total of 14 DEMRGs were identified, which were mainly involved in mitophagy‑related processes and pathways. Clustering analysis indicated the expression levels of 14 DEMRGs except for microtubule‑associated protein 1 light chain‑3β, which was significantly different. Moreover, combination with LASSO, receiver operating characteristic curve and the validation dataset resulted in the identification of the mitochondrial transcription termination factor 3 (MTERF3). The infiltrating abundance of the majority of the immune cells was higher in COPD samples than that noted in the control samples; MTERF3 demonstrated the optimal correlation with macrophages, myeloid‑derived suppressor cells, regulatory T cells and activated cluster of differentiation 8 T cells. Further analysis revealed that MTERF3 expression was increased in CSE‑treated 16HBE cells and knockdown of MTERF3 expression promoted mitophagy. These findings provide novel insights into the role of mitophagy in COPD and identify novel targets for COPD diagnosis and treatment.

SIRT5 Inhibits Mitophagy and Inflammation of Hypoxia-Induced Pulmonary Hypertension by Regulating the Desuccinylation of PDK1

Hypoxia-induced pulmonary hypertension (HPH), a consequence of lung pathologies, is linked to changes in immune responses and inflammation. SIRT5 is recognized as the only enzyme capable of removing succinyl groups. The focus of this research was to explore the involvement of SIRT5 in HPH and to elucidate the associated mechanisms. Models simulating HPH were created in both living organisms and controlled laboratory settings under conditions of low oxygen. To investigate autophagy, transmission electron microscopy (TEM) was employed for ultrastructural analysis, while reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot were used to measure the expression of autophagy-related genes. Cell viability was determined using the cell counting kit-8 (CCK-8) assay. The concentrations of inflammatory cytokines were quantified using ELISA, and flow cytometry was applied to evaluate reactive oxygen species (ROS) levels. To explore the interaction between PDK1 and SIRT5, co-immunoprecipitation (Co-IP) followed by Western blot analysis was conducted. Findings revealed that low oxygen conditions prompted mitophagy and elevated levels of both mRNA and proteins associated with this process in experiments conducted in organisms as well as in cellular models. Under conditions of low oxygen, the expression of SIRT5 was found to be reduced. Hypoxia enhanced cell viability, ROS level, angiogenesis-related protein levels, and inflammatory cytokine levels in pulmonary microvascular endothelial cells (PMVECs), effects that were reversed upon SIRT5 overexpression. Mechanistically, SIRT5 interacted with PDK1, desuccinylating PDK1 and thereby inhibiting mitophagy and inflammation associated with HPH. In conclusion, SIRT5 inhibited mitophagy and inflammation in HPH by regulating the desuccinylation of PDK1, potentially offering effective therapeutic strategies for treating HPH.

Lysosomal-Mitochondrial Interaction Promotes Tumor Growth in Squamous Cell Carcinoma of the Head and Neck

Communication between intracellular organelles including lysosomes and mitochondria has recently been shown to regulate cellular proliferation and fitness. The way lysosomes and mitochondria communicate with each other [lysosomal-mitochondrial interaction (LMI)] is emerging as a major determinant of tumor proliferation and growth. About 30% of squamous carcinomas [including squamous cell carcinoma of the head and neck (SCCHN)] overexpress transmembrane member 16A (TMEM16A), a calcium-activated chloride channel, which promotes cellular growth and negatively correlates with patient survival. We have recently shown that TMEM16A drives lysosomal biogenesis; however, its impact on mitochondrial function has not been explored. In this study, we show that in the context of high-TMEM16A SCCHN, (i) patients display increased mitochondrial content, specifically complex I; (ii) in vitro and in vivo models uniquely depend on mitochondrial complex I activity for growth and survival; (iii) NRF2 signaling is a critical linchpin that drives mitochondrial function, and (iv) mitochondrial complex I and lysosomal function are codependent for proliferation. Taken together, our data demonstrate that coordinated lysosomal and mitochondrial activity and biogenesis via LMI drive tumor proliferation and facilitate a functional interaction between lysosomal and mitochondrial networks. Therefore, inhibition of LMI instauration may serve as a therapeutic strategy for patients with SCCHN. Implications: Intervention of LMI may serve as a therapeutic approach for patients with high TMEM16A-expressing SCCHN.

Exposure of pregnant and lactating parental mice to aflatoxin B1 promotes hepatotoxicity in offspring mice

Aflatoxin B1 (AFB1) taints feeds stuffs, endangering livestock's health and resulting in the liver and breast damage. At the same time, while breastfeeding, AFB1 crosses the mammary glands and enters the milk, harming the offspring. This study investigated the liver damaging effects of maternal AFB1 exposure during pregnancy and lactation in offspring mice. The livers of 8-day-old offspring mice were obtained from female mice who were administered AFB1 (2 mg/kg) 1 week prior to and 1 week following birth. The results showed that AFB1 increased the levels of malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), pro-inflammatory-related proteins (iNOS, COX-2, IL-6), and apoptosis-related proteins (Caspase-3, Caspase-9, Bax) by AFB1-induced in liver of offspring mice. Furthermore, the use of F40/80, HE, and TUNEL staining further demonstrated the existence of inflammation and apoptosis in the liver. Intriguingly, in the liver of offspring mice, AFB1 increased antioxidant protein and inhibit ferroptosis-related protein activity (FTH, GPX4), mitochondrial function-associated proteins (UQCRC2, COX IV, Cyt C), lipid metabolism-associated proteins (HMGCR, SPEBE1, FAS), and autophagy-related proteins (Atg7, Beclin-1, LC3I/II) in the liver of mice. In conclusion, AFB1 enters the liver of offspring mice through milk, which in turn causes liver injury. This outcome explains how AFB1 exposure affects female animals and their progeny and lays the strategy for livestock prevention.

Integrating single-cell sequencing and machine learning to uncover the role of mitophagy in subtyping and prognosis of esophageal cancer

Globally, esophageal cancer stands as a prominent contributor to cancer-related fatalities, distinguished by its poor prognosis. Mitophagy has a significant impact on the process of cancer progression. This study investigated the prognostic significance of mitophagy-related genes (MRGs) in esophageal carcinoma (ESCA) to elucidate molecular subtypes. By analyzing RNA-seq data from The Cancer Genome Atlas (TCGA), 6451 differentially expressed genes (DEGs) were identified. Cox regression analysis narrowed this list to 14 MRGs with potential prognostic implications. ESCA patients were classified into two distinct subtypes (C1 and C2) based on these genes. Furthermore, leveraging the differentially expressed genes between Cluster 1 and Cluster 2, ESCA patients were classified into two novel subtypes (CA and CB). Importantly, patients in C2 and CA subtypes exhibited inferior prognosis compared to those in C1 and CB (p < 0.05). Functional enrichments and immune microenvironments varied significantly among these subtypes, with C1 and CB demonstrating higher immune checkpoint expression levels. Employing machine learning algorithms like LASSO regression, Random Forest and XGBoost, alongside multivariate COX regression analysis, two core genes: HSPD1 and MAP1LC3B were identified. A prognostic model based on these genes was developed and validated in two external cohorts. Additionally, single-cell sequencing analysis provided novel insights into esophageal cancer microenvironment heterogeneity. Through Coremine database screening, Icaritin emerged as a potential therapeutic candidate to potentially improve esophageal cancer prognosis. Molecular docking results indicated favorable binding efficacies of Icaritin with HSPD1 and MAP1LC3B, contributing to the understanding of the underlying molecular mechanisms of esophageal cancer and offering therapeutic avenues.

Region-specific mitophagy in nucleus pulposus, annulus fibrosus, and cartilage endplate of intervertebral disc degeneration: mechanisms and therapeutic strategies

Intervertebral disc degeneration (IVDD) is a prevalent condition contributing to various spinal disorders, posing a significant global health burden. Mitophagy plays a crucial role in maintaining mitochondrial quantity and quality and is closely associated with the onset and progression of IVDD. Well-documented region-specific mitophagy mechanisms in IVDD are guiding the development of therapeutic strategies. In the nucleus pulposus (NP), impaired mitochondria lead to apoptosis, oxidative stress, senescence, extracellular matrix degradation and synthesis, excessive autophagy, inflammation, mitochondrial instability, and pyroptosis, with key regulatory targets including AMPK, PGC-1α, SIRT1, SIRT3, Progerin, p65, Mfn2, FOXO3, NDUFA4L2, SLC39A7, ITGα5/β1, Nrf2, and NLRP3 inflammasome. In the annulus fibrosus (AF), mitochondrial damage induces apoptosis and oxidative stress mediated by PGC-1α, while in the cartilage endplate (CEP), mitochondrial dysfunction similarly triggers apoptosis and oxidative stress. These mechanistic insights highlight therapeutic strategies such as activating Parkin-dependent and Ub-independent mitophagy pathways for NP, enhancing Parkin-dependent mitophagy for AF, and targeting Parkin-mediated mitophagy for CEP. These strategies include the use of natural ingredients, hormonal modulation, gene editing technologies, targeted compounds, and manipulation of related proteins. This review summarizes the mechanisms of mitophagy in different regions of the intervertebral disc and highlights therapeutic approaches using mitophagy modulators to ameliorate IVDD. It discusses the complex mechanisms of mitophagy and underscores its potential as a therapeutic target. The objective is to provide valuable insights and a scientific basis for the development of mitochondrial-targeted drugs for anti-IVDD.

Exploring the role of parthanatos in CNS injury: Molecular insights and therapeutic approaches

BACKGROUND

Central nervous system (CNS) injury causes severe organ damage due to both damage resulting from the injury and subsequent cell death. However, there are currently no effective treatments for countering the irreversible loss of cell function. Parthanatos is a poly (ADP-ribose) polymerase 1 (PARP-1)-dependent form of programmed cell death that is partly responsible for neural cell death. Consequently, the mechanism by which parthanatos promotes CNS injury has attracted significant scientific interest.

AIM OF REVIEW

Our review aims to summarize the potential role of parthanatos in CNS injury and its molecular and pathophysiological mechanisms. Understanding the role of parthanatos and related molecules in CNS injury is crucial for developing effective treatment strategies and identifying important directions for future in-depth research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Parthanatos (from Thanatos, the personification of death according to Greek mythology) is a type of programmed cell death that is initiated by the overactivation of PARP-1. This process triggers a cascade of reactions, including the accumulation of poly(ADP-ribose) (PAR), the nuclear translocation of apoptosis-inducing factor (AIF) after its release from mitochondria, and subsequent massive DNA fragmentation caused by migration inhibitory factor (MIF) forming a complex with AIF. Secondary molecular mechanisms, such as excitotoxicity and oxidative stress-induced overactivation of PARP-1, significantly exacerbate neuronal damage following initial mechanical injury to the CNS. Furthermore, parthanatos is not only associated with neuronal damage but also interacts with various other types of cell death. This review focuses on the latest research concerning the parthanatos cell death pathway, particularly considering its regulatory mechanisms and functions in CNS damage. We highlight the associations between parthanatos and different cell types involved in CNS damage and discuss potential therapeutic agents targeting the parthanatos pathway.

Dietary salt promotes cognitive impairment through repression of SIRT3/PINK1-mediated mitophagy and fission

Dietary salt is increasingly recognized as an independent risk factor for cognitive impairment. However, the exact mechanisms are not yet fully understood. Mitochondria, which play a crucial role in energy metabolism, are implicated in cognitive function through processes such as mitochondrial dynamics and mitophagy. While mitochondrial dysfunction is acknowledged as a significant determinant of cognitive function, the specific relationship between salt-induced cognitive impairment and mitochondrial health has yet to be fully elucidated. Here, we explored the underlying mechanism of cognitive impairment of mice and N2a cells treated with high-salt focusing on the mitochondrial homeostasis with western blotting, immunofluorescence, electron microscopy, RNA sequencing, and more. We further explored the potential role of SIRT3 in salt-induced mitochondrial dysfunction and synaptic alteration through plasmid transfection and siRNA. High salt diet significantly inhibited mitochondrial fission and blocked mitophagy, leading to dysfunctional mitochondria and impaired synaptic plasticity. Our findings demonstrated that SIRT3 not only promote mitochondrial fission by modulating phosphorylated DRP1, but also rescue mitophagy through promoting PINK1/Parkin-dependent pathway. Overall, our data for the first time indicate that mitochondrial homeostasis imbalance is a driver of impaired synaptic plasticity in a cognitive impairment phenotype that is exacerbated by a long-term high-salt diet, and highlight the protective role of SIRT3 in this process.

Mitochondrial dynamics: Molecular mechanism and implications in endometriosis

Endometriosis affects about 10 % of women of reproductive age, leading to a disabling gynecologic condition. Chronic pain, inflammation, and oxidative stress have been identified as the molecular pathways involved in the progression of this disease, although its precise etiology remains uncertain. Although mitochondria are considered crucial organelles for cellular activity, their dysfunction has been linked to the development of this disease. The purpose of this review is to examine the functioning of the mitochondrion in endometriosis: in particular, we focused on the mitochondrial dynamics of biogenesis, fusion, and fission. Since excessive mitochondrial activity is reported to affect cell proliferation, we also considered mitophagy as a mechanism involved in limiting disease development. To better understand mitochondrial activity, we also considered alterations in circadian rhythms, the gut microbiome, and estrogen receptors: indeed, these mechanisms are also involved in the development of endometriosis. In addition, we focused on recent research about the impact of numerous substances on mitochondrial activity; some of them may offer a future breakthrough in endometriosis treatment by acting on mitochondria and inhibiting cell proliferation.

Improved Efficacy of Triple-Negative Breast Cancer Immunotherapy via Hydrogel-Based Co-Delivery of CAR-T Cells and Mitophagy Agonist

Leaky and structurally abnormal blood vessels and increased pressure in the tumor interstitium reduce the infiltration of CAR-T cells in solid tumors, including triple-negative breast cancer (TNBC). Furthermore, high burden of tumor cells may cause reduction of infiltrating CAR-T cells and their functional exhaustion. In this study, various effector-to-target (E:T) ratio experiments are established to model the treatment using CAR-T cells in leukemia (high E:T ratio) and solid tumor (low E:T ratio). It is found that the antitumor immune response is decreased in solid tumors with low E:T ratio. Furthermore, single cell sequencing is performed to investigate the functional exhaustion at a low ratio. It is revealed that the inhibition of mitophagy-mediated mitochondrial dysfunction diminished the antitumor efficacy of CAR-T-cell therapy. The mitophagy agonist BC1618 is screened via AI-deep learning and cytokine detection, in vivo and in vitro studies revealed that BC1618 significantly strengthened the antitumor response of CAR-T cells via improving mitophagy. Here, injection hydrogels are engineered for the controlled co-delivery of CAR-T cells and BC1618 that improves the treatment of TNBC. Local delivery of hydrogels creates an inflammatory and mitophagy-enhanced microenvironment at the tumor site, which stimulates the CAR-T cells proliferation, provides antitumor ability persistently, and improves the effect of treatment.

Targeting LKB1-AMPK-SIRT1-induced autophagy and mitophagy pathways improves cerebrovascular homeostasis in APP/PS1 mice

BACKGROUND

Alzheimer's disease (AD) is the most common and severe degenerative disorder of the central nervous system in the elderly, profoundly impacting patients' quality of life. However, effective therapeutic agents for AD are still lacking. Bazi Bushen capsule (BZBS) is a traditional Chinese herbal compound with potential neuroprotective effects, yet its underlying mechanisms remain poorly understood.

METHODS

In this study, we utilized APP/PS1 transgenic mice to assess the therapeutic efficacy of BZBS. Initially, we evaluated the spatial learning and memory of the mice using the Barnes maze. The brain microcirculation was assessed through a small-animal ultrasound system, two-photon in vivo imaging, and micro-computed tomography angiography. Molecular, biochemical, and pathological analyses were conducted on brain tissues. Through network pharmacology, we identified potential intervention pathways and targets for BZBS in the treatment of AD, which we subsequently validated both in vivo and in vitro. Additionally, we employed molecular virtual docking screening and biolayer interferometry to elucidate the direct interactions of ginsenoside Rg5 and ginsenoside Ro in BZBS with AMPK and LKB1 proteins.

RESULTS

The BZBS intervention significantly enhanced spatial learning and memory in APP/PS1 mice while decreasing Aβ deposition. Furthermore, BZBS protected cerebrovascular homeostasis and mitigated neuroinflammation, as evidenced by decreased blood-brain barrier permeability, increased expression of tight-junction proteins, and restored cerebral blood flow. Mechanistically, ginsenosides Rg5 and Ro in BZBS directly bind to AMPK and LKB1 proteins, activating the LKB1-AMPK-SIRT1 signaling pathway, promoting autophagy and mitochondrial autophagy, and alleviating oxidative stress damage in endothelial cells.

CONCLUSIONS

BZBS enhances autophagy-related activity, decreases Aβ deposition, and improves endothelial cell homeostasis through the activation of the LKB1-AMPK-SIRT1 signaling pathway, ultimately leading to improved cognitive function in mice with AD. This study highlights the importance of enhancing autophagic activity and maintaining cerebrovascular homeostasis in mitigating cognitive decline in AD, providing evidence and new insights into the application of compound medicines for treating age-related neurological disorders.

Luteolin attenuates LPS-induced damage in IPEC-J2 cells by enhancing mitophagy via AMPK signaling pathway activation

Background

Luteolin (LUT), a flavonoid compound widely present in natural plants, has been extensively studied for its diverse biological properties, involving anti-inflammatory,antioxidant, anti-apoptosis and other properties.

Methods

The aim of this study was to investigate the effect of LUT on lipopolysaccharide (LPS)-induced Intestinal Porcine Epithelial Cell line-J2 (IPEC-J2 cells) damage and its underlying mechanism.

Results

The experiment showed that LPS treatment induced injury in IPEC-J2 cells, leading to tight junction disruption, ROS accumulation, and cell apoptosis. Remarkably, LUT attenuated LPS-induced IPEC-J2 cells damage by the up-regulation of Zonula Occludens-1(ZO-1), Occludin, and Claudin protein 1 (Claudin-1) protein expression levels.Besides, LUT increased the activities of CAT, and SOD and prevented LPS-induced MDA and ROS production. LUT suppressed Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation in LPS-induced IPEC-J2 cells, reducing (Interleukin-1beta) IL-1β and Interleukin-6 (IL-6) expression. Moreover, LUT attenuated LPS-induced apoptosis in IPEC-J2 cells by up-regulating expression of B-cell lymphoma 2 (Bcl-2) and down-regulating expression of Cysteine-aspartic acid protease 3 (Caspase-3), Cysteine - aspartic acid protease 9 (Caspase-9) and Bcl-2-associated X protein (Bax). Furthermore, LUT upregulated the AMP-activated protein kinase (AMPK)/Unc-51 like autophagy activating kinase (ULK) signaling pathway and Parkin-RBR E3 ubiquitin protein ligase (Parkin)/PTEN induced putative kinase 1 (PINK1)-mediated mitophagy in a dose-dependent manner. When AMPK was knocked down by short-hairpin RNA (shRNA), the protective effects of LUT against LPS-induced IPEC-J2 cell damage were weakened, as evidenced by the accumulation of excessive ROS and impaired mitophagy.

Conclusion

In summary, LUT exhibits the ability to protect against LPS-induced damage to intestinal tight junctions by enhancing mitophagy through AMPK activation.

Identification and characterization of mitochondrial autophagy-related genes in osteosarcoma and predicting clinical prognosis

Osteosarcoma (OS), the most prevalent primary malignant bone tumor, is characterized by a poor prognosis and high metastatic potential. Mitochondrial autophagy has been implicated in cancer suppression. This study aimed to identify prognostic genes associated with mitochondrial autophagy in OS. Public datasets, including TARGET-OS, GSE99671, and GSE21257, were retrieved for analysis. Differentially expressed genes (DEGs1) between OS and normal samples were identified from GSE99671. Single-sample Gene Set Enrichment Analysis (ssGSEA) was applied to quantify the enrichment scores of 29 mitochondrial autophagy-related genes (MARGs) in OS samples from TARGET-OS, categorizing them into high- and low-score groups to extract DEGs2. The intersection of DEGs1 and DEGs2 yielded mitochondrial autophagy-associated differentially expressed genes (MDGs). Prognostic genes were subsequently screened through a multi-step regression analysis, and a risk score was computed. TARGET-OS samples were stratified into high- and low-risk groups based on the optimal cutoff value of the risk score. GSEA was conducted between the two risk groups. Additionally, associations between prognostic genes and the immune microenvironment were explored. A total of 31 MDGs were identified from the overlap of 3,207 DEGs1 and 622 DEGs2. Five prognostic genes-KLK2, NRXN1, HES5, OR2W3, and HS3ST4-were further selected. Kaplan-Meier survival analysis indicated significantly reduced survival in the high-risk group. GSEA revealed enrichment in ABC transporter activity and glycolysis/gluconeogenesis pathways. Immunoanalysis demonstrated significant differences in 11 immune cell populations and three immune functions between risk groups, notably myeloid-derived suppressor cells (MDSCs) and Type 1 T helper cells. HS3ST4 exhibited the strongest positive correlation with macrophages, whereas NRXN1 showed the most pronounced negative correlation with memory B cells. Expressions of HAVCR2 and PDCD1LG2 were elevated in the low-risk group. Functional analysis indicated significant differences in dysfunction patterns between risk groups. This study identified five mitochondrial autophagy-related prognostic genes and constructed a risk model, offering novel insights into OS diagnosis and therapeutic strategies.

Mitochondria transplantation transiently rescues cerebellar neurodegeneration improving mitochondrial function and reducing mitophagy in mice

Cerebellar ataxia is the primary manifestation of cerebellar degenerative diseases, and mitochondrial dysfunction in Purkinje cells (PCs) plays a critical role in disease progression. In this study, we investigated the feasibility of mitochondria transplantation as a potential therapeutic approach to rescue cerebellar neurodegeneration and elucidate the associated mechanisms. We constructed a conditional Drp1 knockout model in PCs (PCKO mice), characterized by progressive ataxia. Drp1 knockout resulted in pervasive and progressive apoptosis of PCs and significant activation of surrounding glial cells. Mitochondrial dysfunction, which triggers mitophagy, is a key pathogenic factor contributing to morphological and functional damage in PCs. Transplanting liver-derived mitochondria into the cerebellum of 1-month-old PCKO mice improved mitochondrial function, reduced mitophagy, delayed apoptosis of PCs, and alleviated cerebellar ataxia for up to 3 weeks. These findings demonstrate that mitochondria transplantation holds promise as a therapeutic approach for cerebellar degenerative diseases.

Impact of diet and exercise on mitochondrial quality and mitophagy in Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disorder that affects millions of people worldwide. It is characterized by the accumulation of beta-amyloid and phosphorylated tau, synaptic damage, and mitochondrial abnormalities in the brain, leading to the progressive loss of cognitive function and memory. In AD, emerging research suggests that lifestyle factors such as a healthy diet and regular exercise may play a significant role in delaying the onset and progression of the disease. Mitochondria are often referred to as the powerhouse of the cell, as they are responsible for producing the energy to cells, including neurons to maintain cognitive function. Our article elaborates on how mitochondrial quality and function decline with age and AD, leading to an increase in oxidative stress and a decrease in ATP production. Decline in mitochondrial quality can impair cellular functions contributing to the development and progression of disease with the loss of neuronal functions in AD. This article also covered mitophagy, the process by which damaged or dysfunctional mitochondria are selectively removed from the cell to maintain cellular homeostasis. Impaired mitophagy has been implicated in the progression and pathogenesis of AD. We also discussed the impact of impaired mitophagy implicated in AD, as the accumulation of damaged mitochondria can lead to increased oxidative stress. We expounded how dietary interventions and exercise can help to improve mitochondrial quality, and mitochondrial function and enhance mitophagy in AD. A diet rich in antioxidants, polyphenols, and mitochondria-targeted small molecules has been shown to enhance mitochondrial function and protect against oxidative stress, particularly in neurons with aged and mild cognitively impaired subjects and AD patients. Promoting a healthy lifestyle, mainly balanced diet and regular exercise that support mitochondrial health, in an individual can potentially delay the onset and progression of AD. In conclusion, a healthy diet and regular exercise play a crucial role in maintaining mitochondrial quality and mitochondrial function, in turn, enhancing mitophagy and synaptic activities that delay AD in the elderly populations.

Short-term heat exposure affects thermogenesis and mitophagy in goat brown adipocytes

BACKGROUND

Brown adipose tissue (BAT) has a significant impact in newborn goats on maintaining body temperature through non-shivering thermogenesis in response to cold exposure. However, the roles of heat treatment on BAT thermogenesis are still limited.

RESULTS

This study focused on the effects of short-term heat exposure on goat brown adipocytes. We found that the content of mitochondria and the proteins of UCP1 and PGC1α were increased after 12 h of heat exposure. Additionally, the triglyceride (TG) content was significantly decreased after 1, 2, 6 h of heat exposure. Furthermore, RNA-seq analysis of brown adipocytes after 12 h of heat exposure identified 1091 differentially expressed genes (DEGs). The KEGG enrichment analysis were mainly enriched in thermogenesis, fatty acid metabolism and mitophagy. In addition, we found that the amount of mitophagosomes and expression levels of mitophagy-related protein (LC3BII/LC3BI, BNIP3, and BECN) were elevated after 12 h of heat treatment.

CONCLUSION

These findings collectively indicate that heat exposure enhances the thermogenic capacity and mitophagy level of goat brown adipocytes. Our study provides evidence that heat exposure facilitates adaptive thermogenesis in goat brown adipocytes.

Mechanisms Associated with Mitophagy and Ferroptosis in Cerebral Ischemia-reperfusion Injury

Ischemic stroke (IS) constitutes a major threat to human health. Vascular recanalization by intravenous thrombolysis and mechanical thrombolysis remain the most significant and effective methods for relief of ischemia. Key elements of these treatments include achieving blood-vessel recanalization, restoring brain-tissue reperfusion, and preserving the ischemic penumbra. However, in achieving the therapeutic goals of vascular recanalization, secondary damage to brain tissue from cerebral ischemia-reperfusion injury (CIRI) must also be addressed. Despite advancements in understanding the pathological processes associated with CIRI, effective interventions to prevent its onset and progression are still lacking. Recent research has indicated that mitophagy and ferroptosis are critical mechanisms in the development of CIRI, and significantly contribute to the onset and progression of IS and CIRI because of common targets and co-occurrence mechanisms. Therefore, exploring and summarizing the potential connections between mitophagy and ferroptosis during CIRI is crucial. In the present review, we mainly focused on the mechanisms of mitochondrial autophagy and ferroptosis, and their interaction, in the development of CIRI. We believe that the data show a strong relationship between mitochondrial autophagy and ferroptosis with interactive regulation. This information may underpin new potential approaches for the prevention and treatment of IS and subsequent CIRI.

Regular exercise alleviates metabolic dysfunction-associated steatohepatitis through rescuing mitochondrial oxidative stress and dysfunction in liver

Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by severe mitochondrial dysfunction, associated with the production of mitochondrial reactive oxygen species (mROS). The substantial generation of mROS in the MASH liver, resulting from lipid surplus and electron transport chain (ETC) overload, impairs mitochondrial structure and functionality, thereby contributing to the development of severe hepatic steatosis and inflammation. Regular exercise represents an effective strategy for the treatment of MASH. Understanding the effects of exercise on oxidative stress and mitochondrial function is essential for effective treatment of MASH. This article reviews the pathological alterations in mitochondrial β-oxidation, ETC efficiency and mROS production within MASH liver. Additionally, it discusses how exercise influences the redox state and mitochondrial quality control mechanisms-such as biogenesis, mitophagy, fusion, and fission-within the MASH liver. The article emphasizes the importance of in-depth studies on exercise-induced MASH mitigation through the enhancement of mitochondrial redox balance, quality control, and function. Exploring the relationship between exercise and hepatic mitochondria could provide valuable insights into identifying potential therapeutic targets for MASH.

PTEN: a new dawn in Parkinson's disease treatment

In recent years, the study of phosphatase and tension homolog (PTEN) has gradually become a research hotspot. As an important oncogene, the role of PTEN in cancer has long been widely recognized and intensively studied, but it has been relatively less studied in other diseases. Parkinson's disease (PD) is a neurodegenerative refractory disease commonly observed in middle-aged and elderly individuals. The etiology and pathogenesis of PD are numerous, complex, and incompletely understood. With the continuous deepening of research, numerous studies have proven that PTEN is related to the occurrence of PD. In this review, we discuss the relationship between PTEN and PD through the phosphorylation and ubiquitination of PTEN and other possible regulatory mechanisms, including the role of RNA molecules, exosomes, transcriptional regulation, chemical modification, and subtype variation, with the aim of clarifying the regulatory role of PTEN in PD and better elucidating its pathogenesis. Finally, we summarize the shortcomings of PTEN in PD research and highlight the great potential of its future application in PD clinical treatment. These findings provide research ideas and new perspectives for the possible use of PTEN as a PD therapeutic target for targeted drug development and clinical application in the future.

Effects of hypoxia stress on the milk synthesis in bovine mammary epithelial cells

BACKGROUND

Milk synthesis is an energy-intensive process influenced by oxygen availability. This study investigates how hypoxia affects milk synthesis in BMECs, focusing on key genes involved in lactation and energy metabolism.

METHODS

BMECs were cultured in a normoxic environment and then transferred to a hypoxia chamber with 1% O2 for specified durations. The study evaluated cellular responses through various molecular experiments and RNA sequencing. Small interfering RNA was employed to knock down HIF-1α to investigate whether the lactation-related phenotype alteration depends on HIF-1α.

RESULTS

Hypoxia disrupted milk protein production by reducing mTOR/P70S6K/4EBP1 signaling and downregulating genes critical for amino acid transport and protein synthesis. Triglyceride synthesis increased due to enhanced fatty acid uptake and the upregulation of regulatory proteins, including FASN and PPARγ. Although glucose uptake was elevated under hypoxia, key enzymes for lactose synthesis were downregulated, suggesting a redirection of glucose toward energy production. Mitochondrial function was impaired under hypoxia, with reduced gene expression in TCA cycle, ETC, cytosol-mitochondrial transport, decreased ATP levels, increased ROS levels, and structural alterations. Additionally, lipid synthesis and glucose uptake depend on HIF-1α, while milk protein synthesis alterations occurred independently of HIF-1α.

CONCLUSIONS

Hypoxia alters milk synthesis in BMECs by disrupting milk protein synthesis, enhancing lipid metabolism, and impairing energy production. These findings provide valuable insights into the molecular mechanisms underlying the effect of oxygen deprivation on lactation efficiency, offering potential targets for mitigating hypoxic stress in the mammary glands of dairy animals.

Costunolide Ameliorates the Methylmalonic Acidemia Via the PINK1/Parkin Pathway

Methylmalonic acidemia (MMA) is a congenital organic acidemia characterized by mitochondrial dysfunction due to the abnormal accumulation of intermediate metabolites, which subsequently leads to brain damage. Currently, there are no specific pharmacological treatments available for MMA in clinical practice. Costunolide (COS) is a sesquiterpenoid compound derived from Radix Aucklandiae, it exhibits a broad spectrum of bioactivities. However, its effects on MMA have not yet been evaluated. For in-vivo studies, the MMA rat model was established by subcutaneous injection of methylmalonic acid (MA). The spatial learning memory flexibility observed by Morris water maze and brain damage were restored in MMA rats after COS treatment. JC-1 detection and measurements of oxidative stress indicators were performed to demonstrate that the abnormal mitochondrial membrane potential (MMP) and oxidative stress levels were recovered in hippocampus of MMA rats after COS (20 mg/kg) treatment. The abnormal expression of autophagy-related proteins induced by MMA was also rectified following COS treatment. In-vitro research utilized PC12 cells to further investigate the underlying mechanisms of COS in regulating MMA. Our results indicated that COS (20µM) ameliorated the oxidative stress level and mitophagy. Pink1 knockdown reversed the apoptosis rate and MMP which were improved by COS (20µM). Concurrently, the beneficial effects of COS on ATP concentration, ROS level and autophagy related protein expression level were also offset by PINK1 knockdown. In conclusion, our study confirms that COS promotes mitochondrial autophagy and mitigates oxidative stress via the PINK1/Parkin pathway, thereby improving cognitive impairments associated with MMA.

Important regulatory role of mitophagy in diabetic microvascular complications

Microvascular complications of diabetes pose a significant threat to global health, mainly including diabetic kidney disease (DKD), diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN), and diabetic cardiomyopathy (DCM), which can ultimately lead to kidney failure, blindness, disability, and heart failure. With the increasing prevalence of diabetes, the search for new therapeutic targets for diabetic microvascular complications is imminent. Mitophagy is a widespread and strictly maintained process of self-renewal and energy metabolism that plays an important role in reducing inflammatory responses, inhibiting reactive oxygen species accumulation, and maintaining cellular energy metabolism. Hyperglycemia results in impaired mitophagy, which leads to mitochondrial dysfunction and ultimately exacerbates disease progression. This article summarizes the relevant molecular mechanisms of mitophagy and reviews the current status of research on regulating mitophagy as a potential treatment for diabetic microvascular complications, attempting to give new angles on the treatment of diabetic microvascular complications.

Prohibitin2 knockdown decreases glioma malignant phenotypes and radio-resistance by inhibiting mitophagy

PURPOSE

Prohibitin2 (PHB2), located in inner mitochondrial membrane (IMM), is an important receptor to induce mitophagy. PHB2 was identified as a cancer-promoting factor in most cancers. However, the function of PHB2 in glioma cells remains unclear. This study delved into the impact of PHB2 knockdown on the phenotype, radiosensitivity and mitophagy of glioma cells.

METHODS

PHB2 expression and its clinical relevance in glioma were investigated by western blot, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and TCGA databases. The malignant phenotypes of glioma cells were analyzed in vitro using cell proliferation, cell cycle, wound healing and transwell assay. The radiosensitivity of glioma cells was detected by colony forming assay. The potential mechanism by which PHB2 regulated mitophagy was investigated by coimmunoprecipitation assay.

RESULTS

The expression of PHB2 was significantly upregulated in glioma cells and closely correlated with the malignant degree of glioma. The knockdown of PHB2 inhibited the proliferation, migration and invasion activities of glioma cells. Furthermore, PHB2 knockdown enhanced the radiosensitivity of normoxic and hypoxic glioma cells and suppressed the ionizing radiation-induced mitophagy in glioma cells. Cyanide 3-chlorophenylhydrazone (CCCP), a mitophagy agonist, could reverse the phenotypes and radiosensitivity changes elicited by PHB2 knockdown. Additionally, PHB2 regulated the expression of PGAM5 and PINK1 by directly binding to PARL.

CONCLUSIONS

Our findings revealed that PHB2 knockdown decreased glioma malignant phenotypes and radio-resistance by inhibiting mitophagy via PARL-PGAM5-PINK1-Parkin pathway. PHB2 is a promising candidate target for the development of new therapeutic strategy to enhance the efficacy of radiotherapy for glioma.

Quantitative Lipid Analysis of Extracellular Vesicle Preparations: A Perspective

Quantitative lipidomic analysis performed by mass spectrometry is required for determination of the lipid content of extracellular vesicles (EVs). Such methods can provide information about the total amount of lipids, the lipid species composition, the purity of EV samples as well as the cellular origin of the EVs. There are, however, many pitfalls when performing lipid analyses. Thus, any non-specialist should collaborate with experts in lipidomics. In addition to many good review articles giving advice about lipid analyses, we recommend the information and guidelines published by the Lipidomic Standard Initiative, an interest group affiliated with the International Lipidomics Society.

SQYC formula improves the efficacy of PD-1 monoclonal antibodies in MSS colorectal cancer by regulating dendritic cell mitophagy via the PINK1-Parkin pathway

BACKGROUND

Microsatellite stable (MSS) colorectal carcinomas (CRCs) exhibit poor responsiveness to immunotherapy such as immune checkpoint inhibitors (ICIs). In the realm of clinical cancer treatment, traditional Chinese medicines (TCMs) are extensively utilized for their immunomodulatory properties. Shen Qi Yi Chang (SQYC), a clinical prescription for CRC treatment, improve the life quality of CRC patients and enhance their immune function.

PURPOSE

This study was to reveal the effect and mechanism of SQYC in improving the effect of PD-1 inhibitors in the treatment of MSS-type CRC.

METHODS

CT26-luc in situ CRC tumor model and human CRC organoid model was established to evaluate the anti-tumor efficacy of SQYC combined with PD-1 inhibitor. Flow cytometry analysis was utilized to investigate the effect of SQYC on the infiltration and immune function of TILs and DCs in the immune microenvironment. Following this, RNA sequencing analysis, seahorse, TEM and immunofluorescence were performed to regulation of SQYC on mitophagy in DCs cells. UPLC-Q-TOF/MS and molecular docking were used to reveal the key blood-entering components of SQYC-regulated PINK1-parkin pathway.

RESULTS

The SQYC-containing serum improved the efficacy of sintilimab in MSS CRC organoid model. After combined administration of 11.4 g/kg/day SQYC extract and 5 mg/kg α-PD-1, it was observed that SQYC enhanced the efficacy of PD-1 inhibitor against MSS CRC. Flow cytometry and immunofluorescence analysis revealed an augmented infiltration of tumor-infiltrating lymphocytes (TILs) and an improved antigen presentation function of dendritic cells (DCs). Notably, RNA sequencing analysis demonstrated an evident correlation with mitochondrial function related pathways following SQYC treatment. Mechanistically, SQYC promoted mitophagy in DCs via the PINK1-Parkin pathway, thereby improving mitochondrial quality, energy metabolism, and mitochondrial dynamics. Evaluation of the blood components of SQYC coupled with molecular docking, demonstrated good binding affinity with PINK1/PARKIN/LC3.

CONCLUSION

Our findings highlight SQYC as a promising candidate for improving immunotherapy in MSS CRC, suggesting that targeting PINK1-Parkin in DCs could represent a novel strategy for improving the efficacy of ICIs. Furthermore, it provides new theoretical and scientific underpinnings to enhance the clinical efficacy of immunosuppressants.

Oxymatrine alleviates ALD-induced cardiac hypertrophy by regulating autophagy via activation Nrf2/SIRT3 signaling pathway

BACKGROUND

Cardiac hypertrophy is a prevalent early pathological manifestation in various cardiovascular diseases, lacking effective interventions to impede its progression. Although oxymatrine (OMT) has shown potential benefits for cardiac function, its therapeutic efficacy and mechanism in cardiac hypertrophy remain incompletely understood. Notably, mitochondrial damage and dysregulated autophagy are pivotal pathogenic mechanisms in cardiac hypertrophy.

PURPOSE

We investigate the pharmacological characteristics and mechanism of OMT in mitochondrial function and autophagy in cardiac hypertrophy.

STUDY DESIGN AND METHODS

A murine model of cardiac hypertrophy was induced by aldosterone in combination with high-salt drinking water, while primary cardiomyocyte hypertrophy was induced by aldosterone in vitro. Cardiac hypertrophy was assessed using echocardiography and histopathological staining. Autophagosomes and mitochondrial morphology were visualized by transmission electron microscopy. Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and adenosine triphosphate (ATP) were quantified using commercial kits. The binding affinity of OMT with Nrf2 was assessed through molecular docking. Furthermore, adenovirus, agonists, and inhibitors were employed to modulate Nrf2, followed by quantitative real-time polymerase chain reaction (qRT-PCR), immunoblotting, co-immunoprecipitation, chromatin immunoprecipitation, immunohistochemistry, and cellular thermal shift assay.

RESULTS

OMT effectively attenuated aldosterone-induced cardiac hypertrophy both in vivo and in vitro. OMT promoted the activation of Nrf2, leading to elevated SIRT3 expression and enhanced autophagolysosome fusion, thereby modulating mitophagy and improving mitochondrial function. Moreover, the cardioprotective effects of OMT were abolished upon silencing or inhibition of Nrf2. OMT binds to Nrf2, facilitating its dissociation and nuclear translocation.

CONCLUSION

OMT activates Nrf2, consequently enhancing SIRT3 transcription, restoring autophagic flux, and preserving mitochondrial integrity, thereby mitigating aldosterone-induced cardiac hypertrophy. In summary, our study is the first to discover and confirm that OMT can stabilize Nrf2, promoting its activation and subsequently up-regulating SIRT3, which in turn facilitates mitochondrial autophagy. Additionally, PARKIN appears to play a key role in SIRT3-mediated regulation of mitophagy, warranting further investigation.

TFEB activator protects against ethanol toxicity-induced cardiac injury by restoring mitophagy and autophagic flux

Excessive alcohol consumption is a major cause of alcoholic cardiomyopathy (ACM) and myocardial injury. This study aims to investigate the role of transcription factor EB (TFEB) in ethanol-induced cardiac anomalies using a murine model, AC16 human cardiomyocytes, and human plasma. Wild-type mice treated with a TFEB activator (Compound 1) or vehicle (25 mg/kg/d) were challenged with or without ethanol (3 g/kg/d, i.p.) for three consecutive days. Cardiac geometry and function were evaluated by echocardiography. The expressions of TFEB, molecules related to mitochondria, markers of apoptosis, mitophagy and lysosomes were examined in heart tissues and AC16 cardiomyocytes. Mitochondrial function, lysosome activity, and their localizations were measured in AC16 cardiomyocytes. Levels of TFEB and autophagic markers were also detected in human serum from healthy individuals and patients with ACM. Ethanol administration in mice induced severe cardiac dysfunction accompanied by upregulated P62 and LC3B, downregulated TFEB, lysosomal markers and mitophagy-associated receptors in heart tissues. Ethanol toxicity also led to reduced mitochondrial and lysosomal activity. Interestingly, TFEB activation mitigated the detrimental effects caused by ethanol. Inhibition of autophagy abolished the anti-apoptotic effect of TFEB in AC16 cells. In conclusion, TFEB is beneficial in ethanol-induced cardiac anomalies by reducing apoptosis, recovering lysosomal activity, and restoring proper mitophagy and autophagic flux.

JP4-039 protects chondrocytes from ferroptosis to attenuate osteoarthritis progression by promoting Pink1/Parkin-dependent mitophagy

Background

Osteoarthritis (OA) is the most common degenerative joint disease, and its main pathological mechanism is articular cartilage degeneration. The purpose of this study was to investigate the role of mitophagy in the pathogenesis of chondrocyte ferroptosis in OA.

Methods

The expressions of ferroptosis related proteins (GPX4, FTH1, COX2) and ubiquitin-dependent mitophagy related proteins (PARKIN, PINK1) in the intact and injured areas of OA cartilage were analyzed. Nitro oxide JP4-039, a mitochondrial targeting antioxidant, has bifunctional role of targeting mitochondria. Then we evaluated the potential protective effect of JP4-039 in OA using the destabilization of medial meniscus (DMM)-induced OA model, as well as tert-butyl hydrogen peroxide (TBHP)-treated primary mouse chondrocytes and human cartilage explants.

Results

The concentrations of iron and lipid peroxidation and the expression of ferroptosis drivers in the damaged areas of human OA cartilages were significantly higher than those in the intact cartilage. Pink1/Parkin-dependent mitophagy decreased in the injured area of human OA cartilage and was negatively correlated with ferroptosis. Then, the toxicity and effectiveness of JP4-039 are tested to determine its working concentration. Next, at the molecular biological level, we found that JP4-039 showed the effect of anti-chondrocyte ferroptosis. Moreover, it was verified on DMM-induced OA model mice, that JP4-039 could delay the progression of OA. Finally, JP4-039 was re-verified in vivo and in vitro to inhibit chondrocyte ferroptosis and delay the progression of OA by promoting Pink1/Parkin-dependent mitophagy.

Conclusion

JP4-039 inhibits ferroptosis of chondrocytes by promoting Pink1/Parkin-dependent mitophagy and delays OA progression.

NLRX1 deficiency exacerbates skin inflammation in atopic dermatitis by disrupting mitophagy

NLRX1 is an important regulator of inflammatory signaling in innate immune cells. Recent studies indicate NLRX1 activation may be a novel mechanism for inflammatory diseases, however, it has not been explored in atopic dermatitis (AD). Our study aims to investigate the potential role of NLRX1 in the pathogenesis of AD. We observed a significant decrease in NLRX1 expression in AD skin lesions and MC903-indued AD dermatitis. NLRX1 deficiency exacerbated AD inflammation, characterized by increased skin thickness, exacerbated inflammatory infiltration, and compromised skin barrier function. Mechanistically, NLRX1 regulated TSLP expression through Parkin-PINK1-mediated mitophagy in keratinocytes. Furthermore, topical application of NLRX1 agonist alleviated AD progression, including reduced ear thickness, diminished redness, and improved skin barrier function. This study provides novel insights into the regulatory role of NLRX1 in skin inflammation in AD, highlighting the potential therapeutic implications of targeting NLRX1 and mitophagy in AD treatment.

OPA1 deficiency induces mitophagy through PINK1/Parkin pathway during bovine oocytes maturation

In vitro embryo production (IVP) technology has been increasingly applied to beef cattle breeding. In vitro maturation (IVM) technology is the basis of IVP. However, the quality of in vitro-generated mature oocytes is still poor. Mitochondria are the energy factories of oocytes, so they are crucial for oocyte quality. OPA1 is a protein located on the mitochondrial inner membrane, and its main function is to mediate mitochondrial inner membrane fusion. This work demonstrated that OPA1 is expressed at different stages of meiosis in bovine oocytes. The inhibition of OPA1 activity resulted in a reduced rate of first polar body excretion from bovine oocytes and disruption of the spindle structure. OPA1 deficiency impacted mitochondria by leading to mitochondrial dysfunction, promoting mitochondrial fission, and inducing mitophagy through the PINK1/Parkin pathway. Taken together, our findings suggest that OPA1 is essential for bovine oocyte maturation and that OPA1 deficiency leads to mitochondrial dysfunction and promotes mitochondrial fission as well as mitophagy.

Deciphering the Power of Resveratrol in Mitophagy: From Molecular Mechanisms to Therapeutic Applications

Resveratrol (RES), a natural polyphenolic compound, has garnered significant attention for its therapeutic potential in various pathological conditions. This review explores how RES modulates mitophagy-the selective autophagic degradation of mitochondria essential for maintaining cellular homeostasis. RES promotes the initiation and execution of mitophagy by enhancing PINK1/Parkin-mediated mitochondrial clearance, reducing reactive oxygen species production, and mitigating apoptosis, thereby preserving mitochondrial integrity. Additionally, RES regulates mitophagy through the activation of key molecular targets such as AMP-activated protein kinase (AMPK), the mechanistic target of rapamycin (mTOR), deacetylases (SIRT1 and SIRT3), and mitochondrial quality control (MQC) pathways, demonstrating substantial therapeutic effects in multiple disease models. We provide a detailed account of the biosynthetic pathways, pharmacokinetics, and metabolic characteristics of RES, focusing on its role in mitophagy modulation and implications for medical applications. Potential adverse effects associated with its clinical use are also discussed. Despite its promising therapeutic properties, the clinical application of RES is limited by issues of bioavailability and pharmacokinetic profiles. Future research should concentrate on enhancing RES bioavailability and developing derivatives that precisely modulate mitophagy, thereby unlocking new avenues for disease therapy.