A regulatory signaling loop comprising the PGAM5 phosphatase and CK2 controls receptor-mediated mitophagy

Role of mitophagy in spinal cord ischemia-reperfusion injury

Spinal cord ischemia-reperfusion injury, a severe form of spinal cord damage, can lead to sensory and motor dysfunction. This injury often occurs after traumatic events, spinal cord surgeries, or thoracoabdominal aortic surgeries. The unpredictable nature of this condition, combined with limited treatment options, poses a significant burden on patients, their families, and society. Spinal cord ischemia-reperfusion injury leads to reduced neuronal regenerative capacity and complex pathological processes. In contrast, mitophagy is crucial for degrading damaged mitochondria, thereby supporting neuronal metabolism and energy supply. However, while moderate mitophagy can be beneficial in the context of spinal cord ischemia-reperfusion injury, excessive mitophagy may be detrimental. Therefore, this review aims to investigate the potential mechanisms and regulators of mitophagy involved in the pathological processes of spinal cord ischemia-reperfusion injury. The goal is to provide a comprehensive understanding of recent advancements in mitophagy related to spinal cord ischemia-reperfusion injury and clarify its potential clinical applications.

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

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

Current research on mitochondria‑associated membranes in cardiovascular diseases (Review)

The present study aimed to explore the role of mitochondria‑associated membranes (MAMs) as a key interface between mitochondria and the endoplasmic reticulum (ER) and to evaluate their importance in maintaining the physiological functions of these two organelles. MAMs not only act as a structural bridge between mitochondria and the ER but also widely participate in the regulation of mitochondrial biosynthesis and function, Ca2+ signal transduction, lipid metabolism, oxidative stress response and autophagy. In addition, the specific protein composition of MAMs is increasingly being recognized as having a profound impact on their function, and these proteins play a central role in regulating intercellular communication. Recently, the scientific community has accumulated a large amount of evidence supporting MAMs as potential targets for cardiovascular disease treatment. The present review focuses on the fine structure and multifunctional properties of MAMs and their mechanisms in the occurrence and development of cardiovascular diseases. The goal is to explore the mechanism of MAMs, therapeutic intervention points directly related to cardiovascular diseases, and feasibility of incorporating MAMs into the diagnostic strategy and treatment plan of cardiovascular diseases to provide novel insights and theoretical support for clinical practice in this field. MAMs have great potential as therapeutic targets for various cardiovascular diseases. This finding not only deepens the understanding of the interaction between organelles but also opens up a promising research path for the development of new therapeutic strategies for cardiovascular diseases.

Review of FUNDC1-mediated mitochondrial autophagy in Alzheimer's disease

Mitochondrial autophagy is a critical quality control mechanism that eliminates dysfunctional mitochondria to maintain cellular homeostasis. Among receptor-dependent mitophagy pathways, FUN14 domain-containing 1 (FUNDC1)-a mitochondrial outer membrane protein harboring an LC3-interacting region (LIR)-plays a central role by directly binding to LC3 under stress conditions, thereby initiating autophagosome encapsulation of damaged organelles. Emerging evidence implicates FUNDC1 dysregulation in neurodegenerative diseases, particularly Alzheimer's disease (AD), where defective mitophagy exacerbates hallmark pathologies including Aβ plaque deposition and hyperphosphorylated Tau-driven neurofibrillary tangles. Despite advances, the molecular interplay between FUNDC1 phosphorylation states (e.g., Ser13/Ser17/Tyr18) and AD progression remains poorly defined. This review systematically examines FUNDC1's dual regulatory role in mitophagy, its mechanistic links to Aβ and Tau pathologies, and the therapeutic potential of targeting FUNDC1-associated kinases (e.g., ULK1, CK2) or downstream effectors (e.g., DRP1, OPA1) to counteract mitochondrial dysfunction in AD. By synthesizing recent preclinical and clinical findings, we aim to bridge the gap between FUNDC1 biology and AD therapeutics, highlighting actionable nodes for drug development.

LFHP-1c Attenuates Hepatocellular Carcinoma Viability In Vitro Independent of PGAM5

BACKGROUND/OBJECTIVES

Upregulation of phosphoglycerate mutase 5 (PGAM5) is correlated with reduced survival outcomes in hepatocellular carcinoma (HCC). PGAM5 knockdown or knockout attenuates HCC growth in in vitro and in vivo models. A novel small molecule inhibitor of PGAM5, LFHP-1c, has recently been characterized. The objective of this study was to determine if LFHP-1c effectively reduces HCC viability in cell models.

METHODS

The hepatoma and HCC cell lines, HepG2 and HuH7, respectively, were treated with LFHP-1c. Label-free imaging was used to quantify growth. Cellular viability and reactive oxygen species (ROS) production were measured using luminescent or fluorescent assays. Expression of antioxidant and metabolic proteins was measured by immunoblot. HepG2 and HuH7 PGAM5 knockout cell lines were used as negative controls.

RESULTS

Treatment with LFHP-1c reduced cell growth and viability in HepG2 and HuH7 cell lines. Reactive oxygen species production was upregulated in both wild-type and PGAM5 knockout cell lines following LFHP-1c exposure. Cell viability was reduced following LFHP-1c treatment in PGAM5 knockout cell lines.

CONCLUSIONS

LFHP-1c reduces hepatoma and HCC viability and enhances ROS production, but these effects are independent of PGAM5.

Activating autophagy to eliminate toxic protein aggregates with small molecules in neurodegenerative diseases

Neurodegenerative diseases (NDs), such as Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, and frontotemporal dementia, are well known to pose formidable challenges for their treatment due to their intricate pathogenesis and substantial variability among patients, including differences in environmental exposures and genetic predispositions. One of the defining characteristics of NDs is widely reported to be the buildup of misfolded proteins. For example, Alzheimer disease is marked by amyloid beta and hyperphosphorylated Tau aggregates, whereas Parkinson disease exhibits α-synuclein aggregates. Amyotrophic lateral sclerosis and frontotemporal dementia exhibit TAR DNA-binding protein 43, superoxide dismutase 1, and fused-in sarcoma protein aggregates, and Huntington disease involves mutant huntingtin and polyglutamine aggregates. These misfolded proteins are the key biomarkers of NDs and also serve as potential therapeutic targets, as they can be addressed through autophagy, a process that removes excess cellular inclusions to maintain homeostasis. Various forms of autophagy, including macroautophagy, chaperone-mediated autophagy, and microautophagy, hold a promise in eliminating toxic proteins implicated in NDs. In this review, we focus on elucidating the regulatory connections between autophagy and toxic proteins in NDs, summarizing the cause of the aggregates, exploring their impact on autophagy mechanisms, and discussing how autophagy can regulate toxic protein aggregation. Moreover, we underscore the activation of autophagy as a potential therapeutic strategy across different NDs and small molecules capable of activating autophagy pathways, such as rapamycin targeting the mTOR pathway to clear α-synuclein and Sertraline targeting the AMPK/mTOR/RPS6KB1 pathway to clear Tau, to further illustrate their potential in NDs' therapeutic intervention. Together, these findings would provide new insights into current research trends and propose small-molecule drugs targeting autophagy as promising potential strategies for the future ND therapies. SIGNIFICANCE STATEMENT: This review provides an in-depth overview of the potential of activating autophagy to eliminate toxic protein aggregates in the treatment of neurodegenerative diseases. It also elucidates the fascinating interrelationships between toxic proteins and the process of autophagy of "chasing and escaping" phenomenon. Moreover, the review further discusses the progress utilizing small molecules to activate autophagy to improve the efficacy of therapies for neurodegenerative diseases by removing toxic protein aggregates.

PGAM5 aggravated doxorubicin-induced cardiotoxicity by disturbing mitochondrial dynamics and exacerbating cardiomyocytes apoptosis

Doxorubicin (DOX), a potent chemotherapeutic agent, is widely used for treating malignancies but is limited by its cardiotoxic side effects. Mitochondrial dynamics, encompassing fission and fusion processes, play a pivotal role in maintaining cardiomyocyte function under stress, yet their disruption contributes to DOX-induced cardiotoxicity (DIC). While mitochondrial quality control (MQC) mechanisms are implicated in DIC, the specific molecular players remain unclear. Here, we demonstrate that the mitochondrial phosphatase PGAM5 exacerbates DIC by disturbing mitochondrial dynamics and promoting oxidative stress and apoptosis. We show that DOX induces PGAM5 cleavage via activation of mitochondrial proteases OMA1 and YME1L1. Overexpression of PGAM5 blocks DOX-induced mitochondrial elongation and instead promotes mitochondrial fragmentation by disrupting the balance between fission and fusion, mediated by inducing DRP1 dephosphorylation at Ser637 and exacerbating MFN2 downregulation. In addition, our findings indicate that PGAM5's phosphatase activity, rather than its cleavage, mediates the suppression of DOX-induced mitochondrial elongation. However, PGAM5 overexpression fails to enhance mitophagic clearance of dysfunctional mitochondria. Instead, PGAM5 amplifies DOX-induced oxidative stress and cardiomyocyte apoptosis, without promoting other regulated cell death (RCD) pathways like ferroptosis or pyroptosis. These findings reveal a novel mechanism by which PGAM5 disrupts mitochondrial dynamics and contributes to DIC, highlighting its potential as a therapeutic target for mitigating DOX-induced cardiomyopathy.

Mitophagy in Neurons: Mechanisms Regulating Mitochondrial Turnover and Neuronal Homeostasis

Mitochondrial quality control is instrumental in regulating neuronal health and survival. The receptor-mediated clearance of damaged mitochondria by autophagy, known as mitophagy, plays a key role in controlling mitochondrial homeostasis. Mutations in genes that regulate mitophagy are causative for familial forms of neurological disorders including Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS). PINK1/Parkin-dependent mitophagy is the best studied mitophagy pathway, while more recent work has brought to light additional mitochondrial quality control mechanisms that operate either in parallel to or independent of PINK1/Parkin mitophagy. Here, we discuss our current understanding of mitophagy mechanisms operating in neurons to govern mitochondrial homeostasis. We also summarize progress in our understanding of the links between mitophagic dysfunction and neurodegeneration, and highlight the potential for therapeutic interventions to maintain mitochondrial health and neuronal function.

Mitochondria in focus: From structure and function to their role in human diseases. A review

Mitochondria, double-membraned organelles within all eukaryotic cells, are essential for the proper functioning of the human organism. The frequently used phrase "powerhouses of the cell" fails to adequately capture their multifaceted roles. In addition to producing energy in the form of adenosine triphosphate through oxidative phosphorylation, mitochondria are also involved in apoptosis (programmed cell death), calcium regulation, and signaling through reactive oxygen species. Recent research suggests that they can communicate with one another and influence cellular processes. Impaired mitochondrial function on the one hand, can have widespread and profound effects on cellular and organismal health, contributing to various diseases and age-related conditions. Regular exercise on the other hand, promotes mitochondrial health by enhancing their volume, density, and functionality. Although research has made significant progress in the last few decades, mainly through the use of modern technologies, there is still a need to intensify research efforts in this field. Exploring new approaches to enhance mitochondrial health could potentially impact longevity. In this review, we focus on mitochondrial research and discoveries, examine the structure and diverse roles of mitochondria in the human body, explore their influence on energy metabolism and cellular signaling and emphasize their importance in maintaining overall health.

The role and therapeutic potential of mitophagy in major depressive disorder

Major depressive disorder, also known as MDD, affects more than 264 million people globally, making it a prevalent and critical health challenge. Traditional treatments show limited efficacy in many patients. Therefore, exploring new treatment methods is particularly crucial. Mitophagy, as a regulatory process, can help understand and treat MDD. This paper focuses on the molecular mechanisms of mitophagy, starting from proteins and related pathways, and its role in MDD. The study also explores the associations between mitophagy and neuroinflammation, oxidative stress, neurotransmitter synthesis, and neuroplasticity in MDD and discusses the progress of clinical research on the role of mitophagy in MDD. In addition, the article describes the current pharmaceutical and non-pharmaceutical interventions that can regulate mitophagy in MDD and unravels the potential and challenges of these therapeutic strategies in clinical settings. This article offers a deeper insight into the pathogenesis of MDD and offers a scientific basis for the development of new treatment strategies.

Mitochondrial quality control in cardiomyocytes: safeguarding the heart against disease and ageing

Mitochondria are multifunctional organelles that are important for many different cellular processes, including energy production and biosynthesis of fatty acids, haem and iron-sulfur clusters. Mitochondrial dysfunction leads to a disruption in these processes, the generation of excessive reactive oxygen species, and the activation of inflammatory and cell death pathways. The consequences of mitochondrial dysfunction are particularly harmful in energy-demanding organs such as the heart. Loss of terminally differentiated cardiomyocytes leads to cardiac remodelling and a reduced ability to sustain contraction. Therefore, cardiomyocytes rely on multilayered mitochondrial quality control mechanisms to maintain a healthy population of mitochondria. Mitochondrial chaperones protect against protein misfolding and aggregation, and resident proteases eliminate damaged proteins through proteolysis. Irreparably damaged mitochondria can also be degraded through mitochondrial autophagy (mitophagy) or ejected from cells inside vesicles. The accumulation of dysfunctional mitochondria in cardiomyocytes is a hallmark of ageing and cardiovascular disease. This accumulation is driven by impaired mitochondrial quality control mechanisms and contributes to the development of heart failure. Therefore, there is a strong interest in developing therapies that directly target mitochondrial quality control in cardiomyocytes. In this Review, we discuss the current knowledge of the mechanisms involved in regulating mitochondrial quality in cardiomyocytes, how these pathways are altered with age and in disease, and the therapeutic potential of targeting mitochondrial quality control pathways in cardiovascular disease.

Emerging insights into pulmonary hypertension: the potential role of mitochondrial dysfunction and redox homeostasis

Pulmonary hypertension (PH) is heterogeneous diseases that can lead to death due to progressive right heart failure. Emerging evidence suggests that, in addition to its role in ATP production, changes in mitochondrial play a central role in their pathogenesis, regulating integrated metabolic and signal transduction pathways. This review focuses on the basic principles of mitochondrial redox status in pulmonary vascular and right ventricular disorders, a series of dysfunctional processes including mitochondrial quality control (mitochondrial biogenesis, mitophagy, mitochondrial dynamics, mitochondrial unfolded protein response) and mitochondrial redox homeostasis. In addition, we will summarize how mitochondrial renewal and dynamic changes provide innovative insights for studying and evaluating PH. This will provide us with a clearer understanding of the initial signal transmission of mitochondria in PH, which would further improve our understanding of the pathogenesis of PH.

Mitophagy in Neurodegenerative Diseases: Mechanisms of Action and the Advances of Drug Discovery

Neurodegenerative diseases (NDDs), such as Parkinson's disease (PD) and Alzheimer's disease (AD), are devastating brain diseases and are incurable at the moment. Increasing evidence indicates that NDDs are associated with mitochondrial dysfunction. Mitophagy removes defective or redundant mitochondria to maintain cell homeostasis, whereas deficient mitophagy accelerates the accumulation of damaged mitochondria to mediate the pathologies of NDDs. Therefore, targeting mitophagy has become a valuable therapeutic pathway for the treatment of NDDs. Several mitophagy modulators have been shown to ameliorate neurodegeneration in PD and AD. However, it remains to be further investigated for other NDDs. Here, we describe the mechanism and key signaling pathway of mitophagy and summarize the roles of defective mitophagy on the pathogenesis of NDDs. Further, we underline the development advances of mitophagy modulators for PD and AD therapy, discuss the therapeutic challenges and limitations of the existing modulators, and provide guidelines for mitophagy mechanism exploration and drug design.

Physiological and pathological roles of PGAM5: An update and future trend

PGAM5, a phosphatase found in mitochondria, is crucial for mitochondrial quality control (MQC) through its regulation on mitochondrial dynamics, biogenesis, and mitophagy. Previous studies have shown its involvement in multiple regulated cell deaths (RCDs), including apoptosis, necroptosis, and pyroptosis. The objective of this review is to enhance our comprehension of the involvement of PGAM5 in MQC and RCDs. Additionally, we summarize some novel roles of PGAM5 in cellular senescence, lipid metabolism, and immune response modulation in recent studies. Finally, we discuss PGAM5's contribution to the pathological state of cardiovascular, hepatic, neurological, and neoplastic diseases, offering potential perspectives for future research.

Mitophagy and Its Significance in Periodontal Disease

OBJECTIVES

Periodontal disease is a common chronic inflammatory condition affecting the tissues that support teeth, leading to their destruction. Mitophagy, a specialized form of autophagy responsible for degrading damaged mitochondria, plays a crucial role in maintaining cellular homeostasis. However, its role in periodontal disease progression remains poorly understood. This review aims to summarize recent research on mitophagy's role in periodontal disease pathogenesis.

METHODS

A comprehensive literature review on mitophagy was conducted using PubMed, Scopus, and Web of Science databases, employing keywords related to periodontal disease such as "periodontal," "periodontitis," "gingiva," and "gingivitis."

RESULTS

A review of 18 original studies revealed that mitophagy plays a crucial role in periodontal disease by regulating key pathophysiological mechanisms. Specifically, mitophagy modulates periodontal inflammation by influencing pro-inflammatory cytokines and mitochondrial reactive oxygen species. Additionally, it is essential for alveolar bone remodeling, impacting both bone resorption and regeneration. Mitophagy also regulates cell apoptosis within periodontal tissues, helping to preserve cellular function and tissue integrity during periodontal disease progression.

CONCLUSIONS

Mitophagy regulates periodontal disease pathogenesis by modulating inflammation, bone remodeling, and cell death in periodontal tissues. Further research is needed to explore its therapeutic potential in periodontal disease treatment and improve targeted interventions.

ROS-induced cytosolic release of mitochondrial PGAM5 promotes colorectal cancer progression by interacting with MST3

Aberrant release of mitochondrial reactive oxygen species (mtROS) in response to cellular stress is well known for promoting cancer progression. However, precise molecular mechanism by which mtROS contribute to epithelial cancer progression remains only partially understood. Here, using colorectal cancer (CRC) models, we show that upon sensing excessive mtROS, phosphatase PGAM5, which normally localizes to the mitochondria, undergoes aberrant cleavage by presenilin-associated rhomboid-like protein (PARL), becoming released into the cytoplasm. Cytosolic PGAM5 then directly binds to and dephosphorylates MST3 kinase. This, in turn, prevents STK25-mediated LATS1/2 phosphorylation, leading to YAP activation and CRC progression. Importantly, depletion of MST3 reciprocally promotes accumulation of cytosolic PGAM5 by inducing mitochondrial damage. Taken together, these findings demonstrate how mtROS promotes CRC progression by activating YAP via a post-transcriptional positive feedback loop between PGAM5 and MST3, both of which can serve as potential targets for developing next-generation anti-colon cancer therapeutics.

The dual role of PGAM5 in inflammation

In recent years, the focus on human inflammation in research has increased, with aging-related inflammation widely recognized as a defining characteristic of aging. Inflammation is strongly correlated with mitochondrial dysfunction. Phosphoglycerate mutase family member 5 (PGAM5) is a novel modulator of mitochondrial homeostasis in response to mechanical stimulation. Here we review the structure and sublocalization of PGAM5, introduce its importance in programmed cell death and summarize its crucial roles in the development and progression of inflammatory diseases such as pneumonia, hepatitis, neuroinflammation and aging. Notably, PGAM5 has dual effects on controlling inflammation: distinct PGAM5-mediated mitochondrial functions exhibit cellular heterogeneity, leading to its dual functions in inflammation control. We therefore highlight the double-edged sword nature of PGAM5 as a potential critical regulator and innovative therapeutic target in inflammation. Finally, the challenges and future directions of the use of PGAM5, which has dual properties, as a target molecule in the clinic are discussed. This review provides crucial insights to guide the development of intelligent therapeutic strategies targeting PGAM5-specific regulation to treat intractable inflammatory conditions, as well as the potential extension of its broader application to other diseases to achieve more precise and effective treatment outcomes.

Ferroptosis triggers mitochondrial fragmentation via Drp1 activation

Constitutive mitochondrial dynamics ensure quality control and metabolic fitness of cells, and their dysregulation has been implicated in various human diseases. The large GTPase Dynamin-related protein 1 (Drp1) is intimately involved in mediating constitutive mitochondrial fission and has been implicated in mitochondrial cell death pathways. During ferroptosis, a recently identified type of regulated necrosis driven by excessive lipid peroxidation, mitochondrial fragmentation has been observed. Yet, how this is regulated and whether it is involved in ferroptotic cell death has remained unexplored. Here, we provide evidence that Drp1 is activated upon experimental induction of ferroptosis and promotes cell death execution and mitochondrial fragmentation. Using time-lapse microscopy, we found that ferroptosis induced mitochondrial fragmentation and loss of mitochondrial membrane potential, but not mitochondrial outer membrane permeabilization. Importantly, Drp1 accelerated ferroptotic cell death kinetics. Notably, this function was mediated by the regulation of mitochondrial dynamics, as overexpression of Mitofusin 2 phenocopied the effect of Drp1 deficiency in delaying ferroptosis cell death kinetics. Mechanistically, we found that Drp1 is phosphorylated and activated after induction of ferroptosis and that it translocates to mitochondria. Further activation at mitochondria through the phosphatase PGAM5 promoted ferroptotic cell death. Remarkably, Drp1 depletion delayed mitochondrial and plasma membrane lipid peroxidation. These data provide evidence for a functional role of Drp1 activation and mitochondrial fragmentation in the acceleration of ferroptotic cell death, with important implications for targeting mitochondrial dynamics in diseases associated with ferroptosis.

Fibrosis and Src Signalling in Glaucoma: From Molecular Pathways to Therapeutic Prospects

Glaucoma, a leading cause of irreversible blindness, is characterised by progressive optic nerve damage, with elevated intraocular pressure (IOP) and extracellular matrix (ECM) remodelling in the lamina cribrosa (LC) contributing to its pathophysiology. While current treatments focus on IOP reduction, they fail to address the underlying fibrotic changes that perpetuate neurodegeneration. The Src proto-oncogene, a non-receptor tyrosine kinase, has emerged as a key regulator of cellular processes, including fibroblast activation, ECM deposition, and metabolism, making it a promising target for glaucoma therapy. Beyond its well-established roles in cancer and fibrosis, Src influences pathways critical to trabecular meshwork function, aqueous humour outflow, and neurodegeneration. However, the complexity of Src signalling networks remains a challenge, necessitating further investigation into the role of Src in glaucoma pathogenesis. This paper explores the therapeutic potential of Src inhibition to mitigate fibrotic remodelling and elevated IOP in glaucoma, offering a novel approach to halting disease progression.

Autophagy and Mitophagy in Diabetic Kidney Disease-A Literature Review

Autophagy and mitophagy are critical cellular processes that maintain homeostasis by removing damaged organelles and promoting cellular survival under stress conditions. In the context of diabetic kidney disease, these mechanisms play essential roles in mitigating cellular damage. This review provides an in-depth analysis of the recent literature on the relationship between autophagy, mitophagy, and diabetic kidney disease, highlighting the current state of knowledge, existing research gaps, and potential areas for future investigations. Diabetic nephropathy (DN) is traditionally defined as a specific form of kidney disease caused by long-standing diabetes, characterized by the classic histological lesions in the kidney, including mesangial expansion, glomerular basement membrane thickening, nodular glomerulosclerosis (Kimmelstiel-Wilson nodules), and podocyte injury. Clinical markers for DN are albuminuria and the gradual decline in glomerular filtration rate (GFR). Diabetic kidney disease (DKD) is a broader and more inclusive term, for all forms of chronic kidney disease (CKD) in individuals with diabetes, regardless of the underlying pathology. This includes patients who may have diabetes-associated kidney damage without the typical histological findings of diabetic nephropathy. It also accounts for patients with other coexisting kidney diseases (e.g., hypertensive nephrosclerosis, ischemic nephropathy, tubulointerstitial nephropathies), even in the absence of albuminuria, such as a reduction in GFR.

How do lifestyle and environmental factors influence the sperm epigenome? Effects on sperm fertilising ability, embryo development, and offspring health

Recent studies support the influence of paternal lifestyle and diet before conception on the health of the offspring via epigenetic inheritance through sperm DNA methylation, histone modification, and small non-coding RNA (sncRNA) expression and regulation. Smoking may induce DNA hypermethylation in genes related to anti-oxidation and insulin resistance. Paternal diet and obesity are associated with greater risks of metabolic dysfunction in offspring via epigenetic alterations in the sperm. Metabolic changes, such as high blood glucose levels and increased body weight, are commonly observed in the offspring of fathers subjected to chronic stress, in addition to an enhanced risk of depressive-like behaviour and increased sensitivity to stress in both the F0 and F1 generations. DNA methylation is correlated with alterations in sperm quality and the ability to fertilise oocytes, possibly via a differentially regulated MAKP81IP3 signalling pathway. Paternal exposure to toxic endocrine-disrupting chemicals (EDCs) is also linked to the transgenerational transmission of increased predisposition to disease, infertility, testicular disorders, obesity, and polycystic ovarian syndrome (PCOS) in females through epigenetic changes during gametogenesis. As the success of assisted reproductive technology (ART) is also affected by paternal diet, BMI, and alcohol consumption, its outcomes could be improved by modifying factors that are dependent on male lifestyle choices and environmental factors. This review discusses the importance of epigenetic signatures in sperm-including DNA methylation, histone retention, and sncRNA-for sperm functionality, early embryo development, and offspring health. We also discuss the mechanisms by which paternal lifestyle and environmental factors (obesity, smoking, EDCs, and stress) may impact the sperm epigenome.

Empagliflozin promotes skin flap survival by activating AMPK signaling pathway

Flaps are widely used in surgical wound repair, yet distal necrosis poses a significant postoperative challenge, stemming from potential factors such as inadequate blood perfusion, inflammation, ischemia/reperfusion (I/R) injury, mitochondrial impairment, and subsequent ferroptosis. Empagliflozin (EMPA), a sodium-glucose cotransporter 2 inhibitor, has pharmacological activities that promote angiogenesis, mitophagy, and inhibit inflammation, I/R injury, and ferroptosis. However, it is unclear whether EMPA can enhance flap survival. Here, we established a modified McFarlane flap model and applied EMPA to demonstrate its mechanism of action. 24 rats were evenly divided into four groups: the control, low-dose EMPA (10 mg/kg), high-dose EMPA (30 mg/kg), and inhibitor groups. Molecular biology experiments demonstrated that EMPA promoted the expression of angiogenesis-related factors vascular endothelial growth factor (VEGF) and CD34. Additionally, it also increased superoxide dismutase (SOD) activity and reduced malondialdehyde (MDA) levels, thus suppressing oxidative stress. EMPA further alleviated inflammation by downregulating the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In vitro experiments showed that EMPA promoted the proliferation of human umbilical vein endothelial cells (HUVECs) and reduce their reactive oxygen species (ROS) production. Further investigation demonstrated that EMPA improves flap prognosis by inducing the expression of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, further promoting mitophagy and inhibiting ferroptosis. These effects collectively contributed to the survival of the skin flap. Overall, our research elucidates the protective effects of EMPA on flap survival and its specific mechanisms, offering new insights into solving post-transplant flap necrosis.

Disruption of tumor-intrinsic PGAM5 increases anti-PD-1 efficacy through the CCL2 signaling pathway

BACKGROUND

Immunosuppressive phenotype compromised immunotherapy efficacy of hepatocellular carcinoma. Tumor cells intrinsic mitochondria dynamics could pass effects on the extracellular microenvironment through mtDNA stress. PGAM5 anchors at mitochondria and regulates mitochondria functions. We aim to explore whether the regulation of tumor-intrinsic PGAM5 on mitochondria affects tumor-infiltrating immune cells in the microenvironment and whether tumor-intrinsic PGAM5 can be a therapeutic target to enhance the immunotherapy efficacy of hepatocellular carcinoma (HCC).

METHODS

We analyzed the correlation of PGAM5 expression and immune cells infiltration using Gene Expression Omnibus (GEO) and The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) data sets based on cibersort algorithm and tumor-tissue arrays from two independent cohorts. To further validate our findings, we established subcutaneous and orthotopic mouse HCC models with tumor-intrinsic Pgam5 deficiency and analyzed tumor-infiltrating immune cells by flow cytometry and single-cell RNA sequencing. Mechanistically, we established an in vitro co-culture system and analyzed proteomics data to find out the bridge between tumor cell PGAM5 and tumor-associated macrophages (TAMs) in the microenvironment. Immunofluorescence, chromatin-immunoprecipitation, ELISA, mass spectrometry were conducted to explore the molecular pathway. Macrophages were depleted to investigate whether the effects of tumor-intrinsic PGAM5 on TAMs could affect immunotherapy efficacy in HCC orthotopic and subcutaneous mouse models.

RESULTS

PGAM5 expression in tumor was positively correlated with M2-phenotype TAM infiltration in patients with both HCC and mouse HCC tumor models. High tumor-intrinsic PGAM5 expression promoting M2 TAMs infiltration correlated with poor clinical-pathological characteristics and prognosis in patients with HCC. Disruption of tumor-intrinsic Pgam5 reduced TAM M2 polarization and inhibited HCC tumor growth in tumor-bearing mice. Mechanistically, in HCC cells PGAM5 deficiency inhibited mitochondria fission by promoting TRIM28 binding with DRP1, which increased ubiquitination and degradation of DRP1. Tumor-intrinsic PGAM5 deficiency mediated mitochondria fusion and reduced cytosolic mtDNA stress which attenuated TLR9 activation and downstream NF-κB-regulated CCL2 secretion. Furthermore, disruption of tumor-intrinsic Pgam5 significantly facilitated CD8+ T cells activation and improved anti-programmed cell death protein-1 therapeutic efficacy with macrophages depletion compromising synergistic antitumor immune response.

CONCLUSION

Our results shed light on the effect of tumor mitochondria dynamics on TAMs in tumor microenvironment. Tumor-intrinsic PGAM5 can be a therapeutic target to improve immunotherapy efficacy in patients with HCC.

Role of mitophagy in intervertebral disc degeneration: A narrative review

OBJECTIVE

The pivotal role of mitophagy in the initiation and progression of intervertebral disc (IVD) degeneration (IDD) has become increasingly apparent due to a growing body of research on its pathogenesis. This review summarizes the role of mitophagy in IDD and the therapeutic potential of targeting this process.

DESIGN

This narrative review is divided into three parts: the regulatory mechanisms of mitophagy, the role of mitophagy in IDD, and the applications and prospects of mitophagy for the treatment of IDD.

RESULTS

Mitophagy protects cells against harmful external stimuli and plays a crucial protective role by promoting extracellular matrix (ECM) production, inhibiting ECM degradation, and reducing apoptosis, senescence, and cartilage endplate calcification. However, excessive mitophagy is often detrimental to cells. Currently, the regulatory mechanisms governing appropriate and excessive mitophagy remain unclear.

CONCLUSIONS

Proper mitophagy effectively maintains IVD cell homeostasis and slows the progression of IDD. Conversely, excessive mitophagy may accelerate IDD development. Further research is needed to elucidate the regulatory mechanisms underlying appropriate and excessive mitophagy, which could provide new theoretical support for the application of mitophagy targeting to the treatment of IDD.

Mitophagy in ischemic heart disease: molecular mechanisms and clinical management

The influence of the mitochondrial control system on ischemic heart disease has become a major focus of current research. Mitophagy, as a very crucial part of the mitochondrial control system, plays a special role in ischemic heart disease, unlike mitochondrial dynamics. The published reviews have not explored in detail the unique function of mitophagy in ischemic heart disease, therefore, the aim of this paper is to summarize how mitophagy regulates the progression of ischemic heart disease. We conclude that mitophagy affects ischemic heart disease by promoting cardiomyocyte hypertrophy and fibrosis, the progression of oxidative stress, the development of inflammation, and cardiomyocyte death, and that the specific mechanisms of mitophagy are worthy of further investigation.

AMPK regulates Bcl2-L-13-mediated mitophagy induction for cardioprotection

The accumulation of damaged mitochondria in the heart is associated with heart failure. Mitophagy is an autophagic degradation system that specifically targets damaged mitochondria. We have reported previously that Bcl2-like protein 13 (Bcl2-L-13) mediates mitophagy and mitochondrial fission in mammalian cells. However, the in vivo function of Bcl2-L-13 remains unclear. Here, we demonstrate that Bcl2-L-13-deficient mice and knockin mice, in which the phosphorylation site (Ser272) on Bcl2-L-13 was changed to Ala, showed left ventricular dysfunction in response to pressure overload. Attenuation of mitochondrial fission and mitophagy led to impairment of ATP production in these mouse hearts. In addition, we identified AMPKα2 as the kinase responsible for the phosphorylation of Bcl2-L-13 at Ser272. These results indicate that Bcl2-L-13 and its phosphorylation play an important role in maintaining cardiac function. Furthermore, the amplitude of stress-stimulated mitophagic activity could be modulated by AMPKα2.

Mitochondrial quality control: the real dawn of intervertebral disc degeneration?

Intervertebral disc degeneration is the most common disease in chronic musculoskeletal diseases and the main cause of low back pain, which seriously endangers social health level and increases people's economic burden. Disc degeneration is characterized by NP cell apoptosis, extracellular matrix degradation and disc structure changes. It progresses with age and under the influence of mechanical overload, oxidative stress and genetics. Mitochondria are not only the energy factories of cells, but also participate in a variety of cellular functions such as calcium homeostasis, regulation of cell proliferation, and control of apoptosis. The mitochondrial quality control system involves many mechanisms such as mitochondrial gene regulation, mitochondrial protein import, mitophagy, and mitochondrial dynamics. A large number of studies have confirmed that mitochondrial dysfunction is a key factor in the pathological mechanism of aging and intervertebral disc degeneration, and balancing mitochondrial quality control is extremely important for delaying and treating intervertebral disc degeneration. In this paper, we first demonstrate the molecular mechanism of mitochondrial quality control in detail by describing mitochondrial biogenesis and mitophagy. Then, we describe the ways in which mitochondrial dysfunction leads to disc degeneration, and review in detail the current research on targeting mitochondria for the treatment of disc degeneration, hoping to draw inspiration from the current research to provide innovative perspectives for the treatment of disc degeneration.

Identification and validation of protein biomarkers for predicting gastrointestinal stromal tumor recurrence

We conducted a proteomic analysis using mass spectrometry to identify and validate protein biomarkers for accurately predicting recurrence risk in gastrointestinal stromal tumors (GIST) patients, focusing on differentially expressed proteins in metastatic versus primary GIST tissues. We selected five biomarkers-GPX4, RBM4, TPM3, PFKFB2, and PGAM5-and validated their expressions in primary tumors of recurrent and non-recurrent GIST patients via immunohistochemistry. Our analysis of the association between these biomarkers with recurrence-free survival (RFS) and overall survival (OS), along with their interrelationships, revealed that immunohistochemistry confirmed significantly higher expressions of these biomarkers in primary GIST tissues of recurrent patients. Kaplan-Meier survival analysis showed that high expressions of GPX4, RBM4, TPM3, PFKFB2, and PGAM5 correlated with lower RFS, and GPX4 and RBM4 with lower OS. All biomarker pairs showed positive associations, with high expressions correlating with increased recurrence rates, and GPX4 and RBM4 with higher mortality rates. In conclusion, the biomarkers GPX4, RBM4, TPM3, PFKFB2, and PGAM5 are clinically relevant for predicting GIST recurrence, with their high expressions in primary tumors linked to poorer RFS and OS. They serve as potential prognostic indicators, enabling early treatment and improved outcomes. The observed interrelationships among these biomarkers further validate their accuracy in predicting GIST recurrence.

AdipoR1 promotes pathogenic Th17 differentiation by regulating mitochondrial function through FUNDC1

Adiponectin receptor 1 ( Adipor1) deficiency has been shown to inhibit Th17 cell differentiation and reduce joint inflammation and bone erosion in antigen-induced arthritis (AIA) mice. Additional emerging evidence indicates that Th17 cells may differentiate into pathogenic (pTh17) and non-pathogenic (npTh17) cells, with the pTh17 cells playing a crucial role in numerous autoimmune and inflammatory conditions. In the current study, we found that Adipor1 deficiency inhibited pTh17 differentiation in vitro and that the deletion of Adipor1 in pTh17 cells reduced the mitochondrial function. RNA-sequencing (RNA-seq) demonstrated a significant increase in the expression levels of Fundc1, a gene related to mitochondrial function, in Adipor1-deficient CD4 + T cells. Interference with the Fundc1 expression in Adipor1-deficient CD4 + T cells partially mitigated the effect of Adipor1 deficiency on mitochondrial function and pTh17 differentiation. In conclusion, the current study demonstrated a novel role of AdipoR1 in regulating mitochondrial function via FUNDC1 to promote pTh17 cell differentiation, providing some insights into potential therapeutic targets for autoimmune and inflammatory diseases.

Hypoxia-induced mitochondrial fission regulates the fate of bone marrow mesenchymal stem cells by maintaining HIF1α stabilization

For mesenchymal stem cells derived from bone marrow, a controlled reduction in ambient oxygen concentration has been recognized as a facilitator of osteogenic differentiation and the formation of calcium nodules. However, the specific molecular mechanisms underlying this phenotype remain unclear. The aim of this study was to elucidate the impact of hypoxia on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and to explore the involvement of mitophagy and the regulation of mitochondrial dynamics mediated by the mitochondrial dynamic regulatory factor FUN14 domain-containing 1 (FUNDC1). Our findings suggest that FUNDC1 is required for promoting osteogenic differentiation in BMSCs under hypoxic conditions. However, this effect was not dependent on FUNDC1-mediated mitophagy but rather on FUNDC1-mediated regulation of mitochondrial fission. At the mechanistic level, FUNDC1 binds more DNM1L and less OPA1 under hypoxic conditions, leading to an upsurge in mitochondrial division. This heightened mitochondrial division culminates in the increased translocation of Parkin to mitochondria, diminishing its interactions with HIF1α in the cytoplasm and consequently facilitating HIF1α deubiquitination and stabilization. In summary, FUNDC1-regulated mitochondrial division in hypoxic culture emerges as a critical determinant for the translocation of Parkin to mitochondria, ultimately maintaining HIF1α stabilization and promoting osteogenic differentiation.

Mechanisms of mitochondrial resilience in teleostean radial glia under hypoxic stress

Radial glial cells (RGCs) are remarkable cells, essential for normal development of the vertebrate central nervous system. In teleost fishes, RGCs play a pivotal role in neurogenesis and regeneration of injured neurons and glia. RGCs also exhibit resilience to environmental stressors like hypoxia via metabolic adaptations. In this study, we assessed the physiology of RGCs following varying degrees of hypoxia, with an emphasis on reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), mitophagy, and energy metabolism. Our findings demonstrated that hypoxia significantly elevated ROS production and induced MMP depolarization in RGCs. The mitochondrial disturbances were closely associated with increased mitophagy, based on the co-localization of mitochondria and lysosomes. Key mitophagy-related genes were also up-regulated, including those of the BNIP3/NIX mediated pathway as well as the FUNDC1 mediated pathway. Such responses suggest robust cellular mechanisms are initiated to counteract mitochondrial damage due to increasing hypoxia. A significant metabolic shift from oxidative phosphorylation to glycolysis was also observed in RGCs, which may underlie an adaptive response to sustain cellular function and viability following a reduction in oxygen availability. Furthermore, hypoxia inhibited the synthesis of mitochondrial complexes subunits in RGCs, potentially related to elevated HIF-2α expression with 3 % O2. Taken together, RGCs appear to exhibit complex adaptive responses to hypoxic stress, characterized by metabolic reprogramming and the activation of mitophagy pathways to mitigate mitochondrial dysfunction.

Targeting selective autophagy in CNS disorders by small-molecule compounds

Autophagy functions as the primary cellular mechanism for clearing unwanted intracellular contents. Emerging evidence suggests that the selective elimination of intracellular organelles through autophagy, compared to the increased bulk autophagic flux, is crucial for the pathological progression of central nervous system (CNS) disorders. Notably, autophagic removal of mitochondria, known as mitophagy, is well-understood in an unhealthy brain. Accumulated data indicate that selective autophagy of other substrates, including protein aggregates, liposomes, and endoplasmic reticulum, plays distinctive roles in various pathological stages. Despite variations in substrates, the molecular mechanisms governing selective autophagy can be broadly categorized into two types: ubiquitin-dependent and -independent pathways, both of which can be subjected to regulation by small-molecule compounds. Notably, natural products provide the remarkable possibility for future structural optimization to regulate the highly selective autophagic clearance of diverse substrates. In this context, we emphasize the selectivity of autophagy in regulating CNS disorders and provide an overview of chemical compounds capable of modulating selective autophagy in these disorders, along with the underlying mechanisms. Further exploration of the functions of these compounds will in turn advance our understanding of autophagic contributions to brain disorders and illuminate precise therapeutic strategies for these diseases.

Interactions Between Ferroptosis and Oxidative Stress in Ischemic Stroke

Ischemic stroke is a devastating condition that occurs due to the interruption of blood flow to the brain, resulting in a range of cellular and molecular changes. In recent years, there has been growing interest in the role of ferroptosis, a newly identified form of regulated cell death, in ischemic stroke. Ferroptosis is driven by the accumulation of lipid peroxides and is characterized by the loss of membrane integrity. Additionally, oxidative stress, which refers to an imbalance between prooxidants and antioxidants, is a hallmark of ischemic stroke and significantly contributes to the pathogenesis of the disease. In this review, we explore the interactions between ferroptosis and oxidative stress in ischemic stroke. We examine the underlying mechanisms through which oxidative stress induces ferroptosis and how ferroptosis, in turn, exacerbates oxidative stress. Furthermore, we discuss potential therapeutic strategies that target both ferroptosis and oxidative stress in the treatment of ischemic stroke. Overall, this review highlights the complex interplay between ferroptosis and oxidative stress in ischemic stroke and underscores the need for further research to identify novel therapeutic targets for this condition.

RABIF promotes hepatocellular carcinoma progression through regulation of mitophagy and glycolysis

The RAB interacting factor (RABIF) is a putative guanine nucleotide exchange factor that also functions as a RAB-stabilizing holdase chaperone. It has been implicated in pathogenesis of several cancers. However, the functional role and molecular mechanism of RABIF in hepatocellular carcinoma (HCC) are not entirely known. Here, we demonstrate an upregulation of RABIF in patients with HCC, correlating with a poor prognosis. RABIF inhibition results in decreased HCC cell growth both in vitro and in vivo. Our study reveals that depleting RABIF attenuates the STOML2-PARL-PGAM5 axis-mediated mitophagy. Consequently, this reduction in mitophagy results in diminished mitochondrial reactive oxygen species (mitoROS) production, thereby alleviating the HIF1α-mediated downregulation of glycolytic genes HK1, HKDC1, and LDHB. Additionally, we illustrate that RABIF regulates glucose uptake by controlling RAB10 expression. Importantly, the knockout of RABIF or blockade of mitophagy sensitizes HCC cells to sorafenib. This study uncovers a previously unrecognized role of RABIF crucial for HCC growth and identifies it as a potential therapeutic target.

Mitochondrial Function and Dysfunction in White Adipocytes and Therapeutic Implications

For a long time, white adipocytes were thought to function as lipid storages due to the sizeable unilocular lipid droplet that occupies most of their space. However, recent discoveries have highlighted the critical role of white adipocytes in maintaining energy homeostasis and contributing to obesity and related metabolic diseases. These physiological and pathological functions depend heavily on the mitochondria that reside in white adipocytes. This article aims to provide an up-to-date overview of the recent research on the function and dysfunction of white adipocyte mitochondria. After briefly summarizing the fundamental aspects of mitochondrial biology, the article describes the protective role of functional mitochondria in white adipocyte and white adipose tissue health and various roles of dysfunctional mitochondria in unhealthy white adipocytes and obesity. Finally, the article emphasizes the importance of enhancing mitochondrial quantity and quality as a therapeutic avenue to correct mitochondrial dysfunction, promote white adipocyte browning, and ultimately improve obesity and its associated metabolic diseases. © 2024 American Physiological Society. Compr Physiol 14:5581-5640, 2024.

Mitophagy in Cell Death Regulation: Insights into Mechanisms and Disease Implications

Mitophagy, a selective form of autophagy, plays a crucial role in maintaining optimal mitochondrial populations, normal function, and intracellular homeostasis by monitoring and removing damaged or excess mitochondria. Furthermore, mitophagy promotes mitochondrial degradation via the lysosomal pathway, and not only eliminates damaged mitochondria but also regulates programmed cell death-associated genes, thus preventing cell death. The interaction between mitophagy and various forms of cell death has recently gained increasing attention in relation to the pathogenesis of clinical diseases, such as cancers and osteoarthritis, neurodegenerative, cardiovascular, and renal diseases. However, despite the abundant literature on this subject, there is a lack of understanding regarding the interaction between mitophagy and cell death. In this review, we discuss the main pathways of mitophagy, those related to cell death mechanisms (including apoptosis, ferroptosis, and pyroptosis), and the relationship between mitophagy and cell death uncovered in recent years. Our study offers potential directions for therapeutic intervention and disease diagnosis, and contributes to understanding the molecular mechanism of mitophagy.

Multiple roles of mitochondrial autophagy receptor FUNDC1 in mitochondrial events and kidney disease

This article reviews the latest research progress on the role of mitochondrial autophagy receptor FUN14 domain containing 1 (FUNDC1) in mitochondrial events and kidney disease. FUNDC1 is a protein located in the outer membrane of mitochondria, which maintains the function and quality of mitochondria by regulating mitochondrial autophagy, that is, the selective degradation process of mitochondria. The structural characteristics of FUNDC1 enable it to respond to intracellular signal changes and regulate the activity of mitochondrial autophagy through phosphorylation and dephosphorylation. During phosphorylation, unc-51-like kinase 1 (ULK1) promotes the activation of mitophagy by phosphorylating Ser17 of FUNDC1. In contrast, Src and CK2 kinases inhibit the interaction between FUNDC1 and LC3 by phosphorylating Tyr18 and Ser13, thereby inhibiting mitophagy. During dephosphorylation, PGAM5 phosphatase enhances the interaction between FUNDC1 and LC3 by dephosphorylating Ser13, thereby activating mitophagy. BCL2L1 inhibits the activity of PGAM5 by interacting with PGAM5, thereby preventing the dephosphorylation of FUNDC1 and inhibiting mitophagy. FUNDC1 plays an important role in mitochondrial events, participating in mitochondrial fission, maintaining the homeostasis of iron and proteins in mitochondrial matrix, and mediating crosstalk between mitochondria, endoplasmic reticulum and lysosomes, which have important effects on cell energy metabolism and programmed death. In the aspect of kidney disease, the abnormal function of FUNDC1 is closely related to the occurrence and development of many diseases. In acute kidney injury (AKI), cardiorenal syndrome (CRS), diabetic nephropathy (DN), chronic kidney disease (CKD) ,renal fibrosis (RF) and renal anemia, FUNDC1-mediated imbalance of mitophagy may be one of the key factors in disease progression. Therefore, in-depth study of the regulatory mechanism and function of FUNDC1 is of great significance for understanding the pathogenesis of renal disease and developing new treatment strategies.

PGAM5 interacts with and maintains BNIP3 to license cancer-associated muscle wasting

Regressing the accelerated degradation of skeletal muscle protein is a significant goal for cancer cachexia management. Here, we show that genetic deletion of Pgam5 ameliorates skeletal muscle atrophy in various tumor-bearing mice. pgam5 ablation represses excessive myoblast mitophagy and effectively suppresses mitochondria meltdown and muscle wastage. Next, we define BNIP3 as a mitophagy receptor constitutively associating with PGAM5. bnip3 deletion restricts body weight loss and enhances the gastrocnemius mass index in the age- and tumor size-matched experiments. The NH2-terminal region of PGAM5 binds to the PEST motif-containing region of BNIP3 to dampen the ubiquitination and degradation of BNIP3 to maintain continuous mitophagy. Finally, we identify S100A9 as a pro-cachectic chemokine via activating AGER/RAGE. AGER deficiency or S100A9 inhibition restrains skeletal muscle loss by weakening the interaction between PGAM5 and BNIP3. In conclusion, the AGER-PGAM5-BNIP3 axis is a novel but common pathway in cancer-associated muscle wasting that can be targetable. Abbreviation: AGER/RAGE: advanced glycation end-product specific receptor; BA1: bafilomycin A1; BNIP3: BCL2 interacting protein 3; BNIP3L: BCL2 interacting protein 3 like; Ckm-Cre: creatinine kinase, muscle-specific Cre; CM: conditioned medium; CON/CTRL: control; CRC: colorectal cancer; FUNDC1: FUN14 domain containing 1; MAP1LC3A/LC3A: microtubule associated protein 1 light chain 3 alpha; PGAM5: PGAM family member 5, mitochondrial serine/threonine protein phosphatase; S100A9: S100 calcium binding protein A9; SQSTM1/p62: sequestosome 1; TOMM20: translocase of outer mitochondrial membrane 20; TIMM23: translocase of inner mitochondrial membrane 23; TSKO: tissue-specific knockout; VDAC1: voltage dependent anion channel 1.

Iron chelators as mitophagy agents: Potential and limitations

Mitochondrial autophagy (mitophagy) is very important process for the maintenance of cellular homeostasis, functionality and survival. Its dysregulation is associated with high risk and progression numerous serious diseases (e.g., oncological, neurodegenerative and cardiovascular ones). Therefore, targeting mitophagy mechanisms is very hot topic in the biological and medicinal research. The interrelationships between the regulation of mitophagy and iron homeostasis are now becoming apparent. In short, mitochondria are central point for the regulation of iron homeostasis, but change in intracellular cheatable iron level can induce/repress mitophagy. In this review, relationships between iron homeostasis and mitophagy are thoroughly discussed and described. Also, therapeutic applicability of mitophagy chelators in the context of individual diseases is comprehensively and critically evaluated.

Relationship between ferroptosis and mitophagy in acute lung injury: a mini-review

Acute lung injury (ALI) is one of the most deadly and prevalent diseases in the intensive care unit. Ferroptosis and mitophagy are pathological mechanisms of ALI. Ferroptosis aggravates ALI, whereas mitophagy regulates ALI. Ferroptosis and mitophagy are both closely related to reactive oxygen species (ROS). Mitophagy can regulate ferroptosis, but the specific relationship between ferroptosis and mitophagy is still unclear. This study summarizes previous research findings on ferroptosis and mitophagy, revealing their involvement in ALI. Examining the functions of mTOR and NLPR3 helps clarify the connection between ferroptosis and mitophagy in ALI, with the goal of establishing a theoretical foundation for potential therapeutic approaches in the future management of ALI.

The interplay between mitochondrial dynamics and autophagy: From a key homeostatic mechanism to a driver of pathology

The complex relationship between mitochondrial dynamics and autophagy illustrates how two cellular housekeeping processes are intimately linked, illuminating fundamental principles of cellular homeostasis and shedding light on disparate pathological conditions including several neurodegenerative disorders. Here we review the basic tenets of mitochondrial dynamics i.e., the concerted balance between fusion and fission of the organelle, and its interplay with macroautophagy and selective mitochondrial autophagy, also dubbed mitophagy, in the maintenance of mitochondrial quality control and ultimately in cell viability. We illustrate how conditions of altered mitochondrial dynamics reverberate on autophagy and vice versa. Finally, we illustrate how altered interplay between these two key cellular processes participates in the pathogenesis of human disorders affecting multiple organs and systems.

Role of mitophagy in pulmonary hypertension: Targeting the mechanism and pharmacological intervention

Mitophagy, a crucial pathway in eukaryotic cells, selectively eliminates dysfunctional mitochondria, thereby maintaining cellular homeostasis via mitochondrial quality control. Pulmonary hypertension (PH) refers to a pathological condition where pulmonary arterial pressure is abnormally elevated due to various reasons, and the underlying pathogenesis remains elusive. This article examines the molecular mechanisms underlying mitophagy, emphasizing its role in PH and the progress in elucidating related molecular signaling pathways. Additionally, it highlights current drug regulatory pathways, aiming to provide novel insights into the prevention and treatment of pulmonary hypertension.

Src inhibition rescues FUNDC1-mediated neuronal mitophagy in ischaemic stroke

BACKGROUND

Ischaemic stroke triggers neuronal mitophagy, while the involvement of mitophagy receptors in ischaemia/reperfusion (I/R) injury-induced neuronal mitophagy remain not fully elucidated. Here, we aimed to investigate the involvement of mitophagy receptor FUN14 domain-containing 1 (FUNDC1) and its modulation in neuronal mitophagy induced by I/R injury.

METHODS

Wild-type and FUNDC1 knockout mice were generated to establish models of neuronal I/R injury, including transient middle cerebral artery occlusion (tMCAO) in vivo and oxygen glucose deprivation/reperfusion in vitro. Stroke outcomes of mice with two genotypes were assessed. Neuronal mitophagy was analysed both in vivo and in vitro. Activities of FUNDC1 and its regulator Src were evaluated. The impact of Src on FUNDC1-mediated mitophagy was assessed through administration of Src antagonist PP1.

RESULTS

To our surprise, FUNDC1 knockout mice subjected to tMCAO showed stroke outcomes comparable to those of their wild-type littermates. Although neuronal mitophagy could be activated by I/R injury, FUNDC1 deletion did not disrupt neuronal mitophagy. Transient activation of FUNDC1, represented by dephosphorylation of Tyr18, was detected in the early stages (within 3 hours) of neuronal I/R injury; however, phosphorylated Tyr18 reappeared and even surpassed baseline levels in later stages (after 6 hours), accompanied by a decrease in FUNDC1-light chain 3 interactions. Spontaneous inactivation of FUNDC1 was associated with Src activation, represented by phosphorylation of Tyr416, which changed in parallel with the level of phosphorylated FUNDC1 (Tyr18) during neuronal I/R injury. Finally, FUNDC1-mediated mitophagy in neurons under I/R conditions can be rescued by pharmacological inhibition of Src.

CONCLUSIONS

FUNDC1 is inactivated by Src during the later stage (after 6 hours) of neuronal I/R injury, and rescue of FUNDC1-mediated mitophagy may serve as a potential therapeutic strategy for treating ischaemic stroke.

GPR50 regulates neuronal development as a mitophagy receptor

Neurons rely heavily on high mitochondrial metabolism to provide sufficient energy for proper development. However, it remains unclear how neurons maintain high oxidative phosphorylation (OXPHOS) during development. Mitophagy plays a pivotal role in maintaining mitochondrial quality and quantity. We herein describe that G protein-coupled receptor 50 (GPR50) is a novel mitophagy receptor, which harbors the LC3-interacting region (LIR) and is required in mitophagy under stress conditions. Although it does not localize in mitochondria under normal culturing conditions, GPR50 is recruited to the depolarized mitochondrial membrane upon mitophagy stress, which marks the mitochondrial portion and recruits the assembling autophagosomes, eventually facilitating the mitochondrial fragments to be engulfed by the autophagosomes. Mutations Δ502-505 and T532A attenuate GPR50-mediated mitophagy by disrupting the binding of GPR50 to LC3 and the mitochondrial recruitment of GPR50. Deficiency of GPR50 causes the accumulation of damaged mitochondria and disrupts OXPHOS, resulting in insufficient ATP production and excessive ROS generation, eventually impairing neuronal development. GPR50-deficient mice exhibit impaired social recognition, which is rescued by prenatal treatment with mitoQ, a mitochondrially antioxidant. The present study identifies GPR50 as a novel mitophagy receptor that is required to maintain mitochondrial OXPHOS in developing neurons.

Mitophagy in fibrotic diseases: molecular mechanisms and therapeutic applications

Mitophagy is a highly precise process of selective autophagy, primarily aimed at eliminating excess or damaged mitochondria to maintain the stability of both mitochondrial and cellular homeostasis. In recent years, with in-depth research into the association between mitophagy and fibrotic diseases, it has been discovered that this process may interact with crucial cellular biological processes such as oxidative stress, inflammatory responses, cellular dynamics regulation, and energy metabolism, thereby influencing the occurrence and progression of fibrotic diseases. Consequently, modulating mitophagy holds promise as a therapeutic approach for fibrosis. Currently, various methods have been identified to regulate mitophagy to prevent fibrosis, categorized into three types: natural drug therapy, biological therapy, and physical therapy. This review comprehensively summarizes the current understanding of the mechanisms of mitophagy, delves into its biological roles in fibrotic diseases, and introduces mitophagy modulators effective in fibrosis, aiming to provide new targets and theoretical basis for the investigation of fibrosis-related mechanisms and disease prevention.

Role of Autophagy and AMPK in Cancer Stem Cells: Therapeutic Opportunities and Obstacles in Cancer

Cancer stem cells represent a resilient subset within the tumor microenvironment capable of differentiation, regeneration, and resistance to chemotherapeutic agents, often using dormancy as a shield. Their unique properties, including drug resistance and metastatic potential, pose challenges for effective targeting. These cells exploit certain metabolic processes for their maintenance and survival. One of these processes is autophagy, which generally helps in energy homeostasis but when hijacked by CSCs can help maintain their stemness. Thus, it is often referred as an Achilles heel in CSCs, as certain cancers tend to depend on autophagy for survival. Autophagy, while crucial for maintaining stemness in cancer stem cells (CSCs), can also serve as a vulnerability in certain contexts, making it a complex target for therapy. Regulators of autophagy like AMPK (5' adenosine monophosphate-activated protein kinase) also play a crucial role in maintaining CSCs stemness by helping CSCs in metabolic reprogramming in harsh environments. The purpose of this review is to elucidate the interplay between autophagy and AMPK in CSCs, highlighting the challenges in targeting autophagy and discussing therapeutic strategies to overcome these limitations. This review focuses on previous research on autophagy and its regulators in cancer biology, particularly in CSCs, addresses the remaining unanswered questions, and potential targets for therapy are also brought to attention.

Physiological functions of ULK1/2

UNC-51-like kinases 1 and 2 (ULK1/2) are serine/threonine kinases that are best known for their evolutionarily conserved role in the autophagy pathway. Upon sensing the nutrient status of a cell, ULK1/2 integrate signals from upstream cellular energy sensors such as mTOR and AMPK and relay them to the downstream components of the autophagy machinery. ULK1/2 also play indispensable roles in the selective autophagy pathway, removing damaged mitochondria, invading pathogens, and toxic protein aggregates. Additional functions of ULK1/2 have emerged beyond autophagy, including roles in protein trafficking, RNP granule dynamics, and signaling events impacting innate immunity, axon guidance, cellular homeostasis, and cell fate. Therefore, it is no surprise that alterations in ULK1/2 expression and activity have been linked with pathophysiological processes, including cancer, neurological disorders, and cardiovascular diseases. Growing evidence suggests that ULK1/2 function as biological rheostats, tuning cellular functions to intra and extra-cellular cues. Given their broad physiological relevance, ULK1/2 are candidate targets for small molecule activators or inhibitors that may pave the way for the development of therapeutics for the treatment of diseases in humans.

Phytochemicals targeting mitophagy: Therapeutic opportunities and prospects for treating Alzheimer's disease

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder and the leading cause of age-related cognitive decline. Recent studies have established a close relationship between mitophagy and the pathogenesis of AD. Various phytochemicals have shown promising therapeutic effects in mitigating the onset and progression of AD. This review offers a comprehensive overview of the typical features of mitophagy and the underlying mechanisms leading to its occurrence in AD, highlighting its significance in the disease's pathogenesis and progression. Additionally, we examine the therapeutic mechanisms of synthetic drugs that induce mitophagy in AD. Finally, we summarize recent advances in research on phytochemicals that regulate mitophagy in the treatment of AD, potentially guiding the development of new anti-AD drugs.

Mitophagy at the crossroads of cancer development: Exploring the role of mitophagy in tumor progression and therapy resistance

Preserving a functional mitochondrial network is crucial for cellular well-being, considering the pivotal role of mitochondria in ensuring cellular survival, especially under stressful conditions. Mitophagy, the selective removal of damaged mitochondria through autophagy, plays a pivotal role in preserving cellular homeostasis by preventing the production of harmful reactive oxygen species from dysfunctional mitochondria. While the involvement of mitophagy in neurodegenerative diseases has been thoroughly investigated, it is becoming increasingly evident that mitophagy plays a significant role in cancer biology. Perturbations in mitophagy pathways lead to suboptimal mitochondrial quality control, catalyzing various aspects of carcinogenesis, including establishing metabolic plasticity, stemness, metabolic reconfiguration of cancer-associated fibroblasts, and immunomodulation. While mitophagy performs a delicate balancing act at the intersection of cell survival and cell death, mounting evidence indicates that, particularly in the context of stress responses induced by cancer therapy, it predominantly promotes cell survival. Here, we showcase an overview of the current understanding of the role of mitophagy in cancer biology and its potential as a target for cancer therapy. Gaining a more comprehensive insight into the interaction between cancer therapy and mitophagy has the potential to reveal novel targets and pathways, paving the way for enhanced treatment strategies for therapy-resistant tumors in the near future.

The Role of Endothelial Cell Mitophagy in Age-Related Cardiovascular Diseases

Aging is a major risk factor for cardiovascular diseases (CVD), and mitochondrial autophagy impairment is considered a significant physiological change associated with aging. Endothelial cells play a crucial role in maintaining vascular homeostasis and function, participating in various physiological processes such as regulating vascular tone, coagulation, angiogenesis, and inflammatory responses. As aging progresses, mitochondrial autophagy impairment in endothelial cells worsens, leading to the development of numerous cardiovascular diseases. Therefore, regulating mitochondrial autophagy in endothelial cells is vital for preventing and treating age-related cardiovascular diseases. However, there is currently a lack of systematic reviews in this area. To address this gap, we have written this review to provide new research and therapeutic strategies for managing aging and age-related cardiovascular diseases.