Decision between mitophagy and apoptosis by Parkin via VDAC1 ubiquitination

Calcium bridges built by mitochondria-associated endoplasmic reticulum membranes: potential targets for neural repair in neurological diseases

The exchange of information and materials between organelles plays a crucial role in regulating cellular physiological functions and metabolic levels. Mitochondria-associated endoplasmic reticulum membranes serve as physical contact channels between the endoplasmic reticulum membrane and the mitochondrial outer membrane, formed by various proteins and protein complexes. This microstructural domain mediates several specialized functions, including calcium (Ca 2+ ) signaling, autophagy, mitochondrial morphology, oxidative stress response, and apoptosis. Notably, the dysregulation of Ca 2+ signaling mediated by mitochondria-associated endoplasmic reticulum membranes is a critical factor in the pathogenesis of neurological diseases. Certain proteins or protein complexes within these membranes directly or indirectly regulate the distance between the endoplasmic reticulum and mitochondria, as well as the transduction of Ca 2+ signaling. Conversely, Ca 2+ signaling mediated by mitochondria-associated endoplasmic reticulum membranes influences other mitochondria-associated endoplasmic reticulum membrane-associated functions. These functions can vary significantly across different neurological diseases-such as ischemic stroke, traumatic brain injury, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease-and their respective stages of progression. Targeted modulation of these disease-related pathways and functional proteins can enhance neurological function and promote the regeneration and repair of damaged neurons. Therefore, mitochondria-associated endoplasmic reticulum membranes-mediated Ca 2+ signaling plays a pivotal role in the pathological progression of neurological diseases and represents a significant potential therapeutic target. This review focuses on the effects of protein complexes in mitochondria-associated endoplasmic reticulum membranes and the distinct roles of mitochondria-associated endoplasmic reticulum membranes-mediated Ca 2+ signaling in neurological diseases, specifically highlighting the early protective effects and neuronal damage that can result from prolonged mitochondrial Ca 2+ overload or deficiency. This article provides a comprehensive analysis of the various mechanisms of Ca 2+ signaling mediated by mitochondria-associated endoplasmic reticulum membranes in neurological diseases, contributing to the exploration of potential therapeutic targets for promoting neuroprotection and nerve repair.

Improving mitochondria-associated endoplasmic reticulum membranes integrity as converging therapeutic strategy for rare neurodegenerative diseases and cancer

Membrane contact sites harbor a distinct set of proteins with varying biological functions, thereby emerging as hubs for localized signaling nanodomains underlying adequate cell function. Here, we will focus on mitochondria-associated endoplasmic reticulum membranes (MAMs), which serve as hotspots for Ca2+ signaling, redox regulation, lipid exchange, mitochondrial quality and unfolded protein response pathway. A network of MAM-resident proteins contributes to the structural integrity and adequate function of MAMs. Beyond endoplasmic reticulum (ER)-mitochondrial tethering proteins, MAMs contain several multi-protein complexes that mediate the transfer of or are influenced by Ca2+, reactive oxygen species and lipids. Particularly, IP3 receptors, intracellular Ca2+-release channels, and Sigma-1 receptors (S1Rs), ligand-operated chaperones, serve as important platforms that recruit different accessory proteins and intersect with these local signaling processes. Furthermore, many of these proteins are directly implicated in pathophysiological conditions, where their dysregulation or mutation is not only causing diseases such as cancer and neurodegeneration, but also rare genetic diseases, for example familial Parkinson's disease (PINK1, Parkin, DJ-1), familial Amyotrophic lateral sclerosis (TDP43), Wolfram syndrome1/2 (WFS1 and CISD2), Harel-Yoon syndrome (ATAD3A). In this review, we will discuss the current state-of-the-art regarding the molecular components, protein platforms and signaling networks underlying MAM integrity and function in cell function and how their dysregulation impacts MAMs, thereby driving pathogenesis and/or impacting disease burden. We will highlight how these insights can generate novel, potentially therapeutically relevant, strategies to tackle disease outcomes by improving the integrity of MAMs and the signaling processes occurring at these membrane contact sites.

GL261 glioblastoma induces delayed body weight gain and stunted skeletal muscle growth in young mice

The survival rate for children and adolescents has increased to over 85%. However, there is limited understanding of the impact of pediatric cancers on muscle development and physiology. Given that brain tumors alone account for 26% of all pediatric cancers, this study aimed to investigate the skeletal muscle consequences of tumor growth in young mice. C2C12 myotubes were cocultured with GL261 murine glioblastoma cells to assess myotube size. GL261 cells were then injected subcutaneously into 4-wk-old male C57BL/6J mice. Animals were euthanized 28 days post-GL261 implantation. Muscle function was tested in vivo and ex vivo. Muscle protein synthesis was estimated via the SUnSET method, and gene/protein expression levels were assessed via Western blotting and qPCR. In vitro, the C2C12 cultures exposed to GL261 exhibited myotube atrophy, consistent with a disrupted anabolic/catabolic balance. In vivo, carcass, heart, and fat mass were significantly reduced in the tumor-bearing mice. Skeletal muscle growth was impeded in the GL261 hosts, along with a smaller muscle cross-sectional area (CSA). Both in vivo muscle torque and the ex vivo Extensor Digitorum Longus (EDL) muscle force were unchanged. At molecular level, the tumor hosts displayed reduced estimations of muscle protein synthesis and increased muscle protein ubiquitination, in disagreement with decreased muscle ubiquitin ligase mRNA expression. Overall, we showed that GL261 tumors impact the growth of pediatric mice by stunting skeletal muscle development, decreasing muscle mass, reducing muscle fiber size, diminishing muscle protein synthesis, and altering protein catabolism signaling.NEW & NOTEWORTHY This study shows that pediatric brain tumors stunt muscle development in young mice. GL261 glioblastoma cells caused myotube atrophy, reduced carcass, heart, and fat mass, and impeded skeletal muscle growth. Tumor-bearing mice had decreased muscle protein synthesis and increased protein ubiquitination. This is the first demonstration that GL261 tumors reduce muscle mass and fiber size, impair muscle function and innervation, and alter muscle protein turnover.

Fatty acid synthesis promotes mtDNA release via ETS1-mediated oligomerization of VDAC1 facilitating endothelial dysfunction in sepsis-induced lung injury

Sepsis involves endothelial cell dysfunction leading to the development of lung injury. Fatty acid synthesis contributes to the development of inflammatory injury in sepsis. However, the regulatory mechanisms of fatty acid synthesis-related endothelial activation remain unclear. In this study, we found that fatty acid synthesis in patients with sepsis was greatly disordered. Inhibition of fatty acid synthesis significantly alleviated sepsis-induced endothelial damage and lung injury both in vitro and in vivo. We further found that the release of mtDNA participated in fatty acid synthesis-related regulation of endothelial inflammatory and coagulation activation. Mechanistically, fatty acid synthesis promoted the oligomerization of voltage-dependent anion channel 1 (VDAC1) via ETS proto-oncogene 1 (ETS1)-mediated inhibition of VDAC1 ubiquitination, thereby leading to the increased release of mtDNA and subsequent activation of cGAS-STING signaling and pyroptosis in endothelial cells. Our findings revealed that fatty acid synthesis promoted endothelial dysfunction through mtDNA release, providing new insight into the therapeutic strategies for treating sepsis-associated lung injury.

SIRT5 modulates mitochondria function via mitophagy and antioxidant mechanisms to facilitate oocyte maturation in mice

Mitochondrial homeostasis, closely associated with mitophagy and antioxidant mechanisms, is essential for proper meiotic spindle assembly and chromosome segregation during oocyte maturation. SIRT5, known to modulate mitochondrial function under various conditions, has been shown to impact oocyte quality when inhibited, however, the precise mechanisms linking SIRT5 to mitochondrial homeostasis during meiotic progression remain unclear. In this study, we demonstrate that SIRT5 localizes predominantly at the periphery of the meiotic spindle and is enriched on chromosomes during oocyte maturation. Inhibition of SIRT5 led to significant meiotic defects, including disrupted spindle organization and chromosome misalignment. These defects were associated with increased histone acetylation, which impaired kinetochore-microtubule attachments. Moreover, SIRT5 inhibition resulted in mitochondrial dysfunction, subsequently elevating ROS levels and triggering oxidative stress, which further exacerbated meiotic abnormalities. Mechanistically, SIRT5 inhibition disrupted the balance of Parkin-dependent mitophagy by inducing ULK phosphorylation. Additionally, it activated the PI3K/Akt signaling pathway, which increased NADPH consumption and reduced GSH levels. Collectively, these findings reveal that SIRT5 plays dual roles in maintaining mitochondrial homeostasis during oocyte maturation: (1) by regulating Parkin-dependent mitophagy to prevent excessive mitochondrial clearance, and (2) by preserving the NADPH/GSH antioxidant system to ensure redox balance. These insights provide potential targets for improving oocyte quality and addressing mitochondrial dysfunction-related reproductive disorders in females.

Tripartite Motif Containing 65 Deficiency Confers Protection Against Acute Kidney Injury via Alleviating Voltage-Dependent Anion Channel 1-Mediated Mitochondrial Dysfunction

Acute kidney injury (AKI) is a prevalent and serious clinical disease with a high incidence rate and significant health burden. The limited understanding of the complex pathological mechanisms has hindered the development of efficacious therapeutics. Tripartite motif containing 65 (TRIM65) has recently been identified as a key regulator of acute inflammation. However, its role in AKI remains unclear. The present study observed that TRIM65 expression was upregulated in AKI. Moreover, the knockout of the Trim65 gene in mice exhibited a substantial protective impact against rhabdomyolysis, ischemia-reperfusion (I/R), and cisplatin-induced AKI. Mechanistically, TRIM65 directly binds and mediates K48/K63-linked polyubiquitination modifications of voltage-dependent anion channel 1 (VDAC1) at its K161 and K200 amino acid sites. TRIM65 plays a role in maintaining the stability of VDAC1 and preventing its degradation by the autophagy pathway. TRIM65 deficiency attenuates mitochondrial dysfunction in renal tubular epithelial cells during AKI. Conversely, the overexpression of VDAC1 in renal tissues has been demonstrated to negate the protective effect of TRIM65 deficiency on AKI. These findings suggest that TRIM65 may play a role regulating of AKI through the targeting of VDAC1-dependent mitochondrial function, offering potential avenues for the development of new drug targets and strategies for the treatment of AKI.

Mitochondria - the CEO of the cell

As we have learned more about mitochondria over the past decades, including about their essential cellular roles and how altered mitochondrial biology results in disease, it has become apparent that they are not just powerplants pumping out ATP at the whim of the cell. Rather, mitochondria are dynamic information and energy processors that play crucial roles in directing dozens of cellular processes and behaviors. They provide instructions to enact programs that regulate various cellular operations, such as complex metabolic networks, signaling and innate immunity, and even control cell fate, dictating when cells should divide, differentiate or die. To help current and future generations of cell biologists incorporate the dynamic, multifaceted nature of mitochondria and assimilate modern discoveries into their scientific framework, mitochondria need a 21st century 'rebranding'. In this Opinion article, we argue that mitochondria should be considered as the 'Chief Executive Organelle' - the CEO - of the cell.

TP53INP2 promotes mitophagic degradation of YAP to impede dedifferentiated liposarcoma development

Dedifferentiated liposarcoma (DDLPS) accounts for 15-20% of liposarcoma (LPS) and has high rates of local recurrence and distant metastasis. Hyperactivation of yes-associated protein (YAP) has been implicated in DDLPS development. However, the mechanisms that drive aberrant YAP signaling remain largely unknown. Here, we show that tumor protein p53 inducible nuclear protein 2 (TP53INP2) is a potential negative modulator of the malignant progression of DDLPS. The TP53INP2 protein expression level in tumor tissues from 79 patients with DDLPS decreased progressively. Compared with primary tumors, recurrent tumors also exhibited reduced TP53INP2 expression. More importantly, low TP53INP2 expression is correlated with poor prognosis. TP53INP2 gain- or loss-of-function experiments in DDLPS cell lines showed profound inhibitory effects on processes and properties linked with cancer malignancy, such as proliferation, migration, stemness and dedifferentiation. Mechanistically, TP53INP2 is located mainly in mitochondria and promotes mitophagic degradation of YAP in a VDAC1-dependent manner. The WW domain in YAP and the PPTY motif in VDAC1 are required for their interaction. Taken together, these data demonstrate that TP53INP2 represses the malignant progression of DDLPS by inactivating YAP via a mitophagy-dependent mechanism and that TP53INP2 may constitute a novel prognostic biomarker for advanced DDLPS.

The idiosyncrasies of oocytes

Animal oocytes face extreme challenges. They remain dormant in the body for long periods of time. To support offspring development and health, they need to store genetic material and maternal factors stably and at the same time manage cellular damage in a reliable manner. Recent studies have provided new insights on how oocytes cope with such challenges. This review discusses the many unusual or idiosyncratic nature of oocytes and how understanding oocyte biology can help us address issues of reproduction and intergenerational inheritance.

Efficient PHB2 (prohibitin 2) exposure during mitophagy depends on VDAC1 (voltage dependent anion channel 1)

Exposure of inner mitochondrial membrane resident protein PHB2 (prohibitin 2) during autophagic removal of depolarized mitochondria (mitophagy) depends on the ubiquitin-proteasome system. This uncovering facilitates the PHB2 interaction with phagophore membrane-associated protein MAP1LC3/LC3. It is unclear whether PHB2 is exposed randomly at mitochondrial rupture sites. Prior knowledge and initial screening indicated that VDAC1 (voltage dependent anion channel 1) might play a role in this phenomenon. Through in vitro biochemical assays and imaging, we have found that VDAC1-PHB2 interaction increases during mitochondrial depolarization. Subsequently, this interaction enhances the efficiency of PHB2 exposure and mitophagy. To investigate the relevance in vivo, we utilized porin (equivalent to VDAC1) knockout Drosophila line. Our findings demonstrate that during mitochondrial stress, porin is essential for Phb2 exposure, Phb2-Atg8 interaction and mitophagy. This study highlights that VDAC1 predominantly synchronizes efficient PHB2 exposure through mitochondrial rupture sites during mitophagy. These findings may provide insights to understand progressive neurodegeneration.

Organellophagy regulates cell death:A potential therapeutic target for inflammatory diseases

BACKGROUND

Dysregulated alterations in organelle structure and function have a significant connection with cell death, as well as the occurrence and development of inflammatory diseases. Maintaining cell viability and inhibiting the release of inflammatory cytokines are essential measures to treat inflammatory diseases. Recently, many studies have showed that autophagy selectively targets dysfunctional organelles, thereby sustaining the functional stability of organelles, alleviating the release of multiple cytokines, and maintaining organismal homeostasis. Organellophagy dysfunction is critically engaged in different kinds of cell death and inflammatory diseases.

AIM OF REVIEW

We summarized the current knowledge of organellophagy (e.g., mitophagy, reticulophagy, golgiphagy, lysophagy, pexophagy, nucleophagy, and ribophagy) and the underlying mechanisms by which organellophagy regulates cell death.

KEY SCIENTIFIC CONCEPTS OF REVIEW

We outlined the potential role of organellophagy in the modulation of cell fate during the inflammatory response to develop an intervention strategy for the organelle quality control in inflammatory diseases.

Impact of Psychological Stress and Spontaneous Tumour Regression on the Hippocampal Proteome in a Mouse Model of Breast Cancer

Cognitive impairment is common in people diagnosed with breast cancer, but the molecular mechanisms that underlie maladaptive changes in the brain are unknown. The psychological stress of a cancer diagnosis is certainly a contributing factor. Here, we investigated alterations in the hippocampal proteome in response to both cancer and psychological stress using label-free quantitative mass spectrometry techniques. An orthotopic syngeneic model of triple-negative breast cancer (TNBC) was established by injecting Py230 cells into the mammary fat pads of female C57Bl/6 mice. Half of the mice were subjected to a daily restraint stress paradigm. Mice that experienced both cancer and restraint stress lost weight and displayed larger tumours compared to non-stressed mice. Their urinary corticosterone levels were also elevated, as measured by enzyme-linked immunosorbent assay. Non-stressed tumour-bearing mice displayed higher levels of TNFα in the prefrontal cortex (PFC) compared to stressed mice with cancer. Flow cytometry results suggested that the CD4+/CD8+ T cell ratios were also raised in non-stressed tumour-bearing mice compared to both controls and stressed mice with TNBC. Bioinformatic analysis of hippocampal proteomes indicated that cancer alone causes reduced mitochondrial respiration and ATP synthesis, as well as impaired glutamate recycling and synaptic plasticity. Moreover, daily stress in TNBC mice caused further mitochondrial dysfunction, increased oxidative phosphorylation, and altered lipid metabolism. Importantly, over half of the mammary tumours that initially developed spontaneously regressed after 7-9 weeks in these young immunocompetent mice. Tumour regression inhibited TNFα increases in the PFC. However, the hippocampal proteomes of tumour-bearing mice were largely similar to mice in which tumours regressed, suggesting that spontaneous regression of breast cancer confers lasting physiological dysregulations that impact hippocampal protein expression. This study in mice may help to identify molecular mechanisms responsible for long-term memory impairments in cancer survivors and reveal novel drug targets for cancer-related cognitive impairment.

NONO interacts with nuclear PKM2 and directs histone H3 phosphorylation to promote triple-negative breast cancer metastasis

BACKGROUND

Emerging evidence has revealed that PKM2 has oncogenic functions independent of its canonical pyruvate kinase activity, serving as a protein kinase that regulates gene expression. However, the mechanism by which PKM2, as a histone kinase, regulates the transcription of genes involved in triple-negative breast cancer (TNBC) metastasis remains poorly understood.

METHODS

We integrated cellular analysis, including cell viability, proliferation, colony formation, and migration assays; biochemical assays, including protein interaction studies and ChIP; clinical sample analysis; RNA-Seq and CUT&Tag data; and xenograft or mammary-specific gene knockout mouse models, to investigate the epigenetic modulation of TNBC metastasis via NONO-dependent interactions with nuclear PKM2.

RESULTS

We report that the transcription factor NONO directly interacts with nuclear PKM2 and directs PKM2-mediated phosphorylation of histone H3 at threonine 11 (H3T11ph) to promote TNBC metastasis. We show that H3T11ph cooperates with TIP60-mediated acetylation of histone H3 at lysine 27 (H3K27ac) to activate SERPINE1 expression and to increase the proliferative, migratory, and invasive abilities of TNBC cells in a NONO-dependent manner. Conditional mammary loss of NONO or PKM2 markedly suppressed SERPINE1 expression and attenuated the malignant progression of spontaneous mammary tumors in mice. Importantly, elevated expression of NONO or PKM2 in TNBC patients is positively correlated with SERPINE1 expression, enhanced invasiveness, and poor clinical outcomes.

CONCLUSION

These findings revealed that the NONO-dependent interaction with nuclear PKM2 is key for the epigenetic modulation of TNBC metastasis, suggesting a novel intervention strategy for treating TNBC.

Diminazine protects against cardiac aging through the improvement of mitophagy and apoptosis in aging rats induced by D-galactose

BACKGROUND

Mitochondrial dysfunction is a main feature of the aged heart. However, there is still no effective treatment against cardiac aging. Diminazine (DIZE) is an anti-infective agent for animals. It is effective against cardiac disorders. The present study aimed to investigate the effects of DIZE on age-related cardiac dysfunction.

METHODS AND RESULTS

Wistar rats were randomly divided into four groups, with eight rats per group: control rats (CONT), control rats treated with DIZE (CONT + DIZE), aged rats induced by D-galactose (D-GAL), aged rats treated with DIZE (D-GAL + DIZE). Rats received intraperitoneal (IP) injection of D-GAL at 150 mg/kg daily for 8 weeks to induce aging. The aging animals in the D-GAL + DIZE group were treated with subcutaneous injection of DIZE at 15 mg/kg daily for 8 weeks. Heart tissues were harvested to assay molecular parameters. Our results exhibited cardiac hypertrophy and a significant increase in the expression of cardiac BCL2-associated X (Bax) along with a significant decrease in the expression of cardiac Mitofusin 2 (Mfn2), Phosphatase, and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), Dynamin-related protein 1 (Drp1), and B-cell lymphoma 2 (Bcl2) in the aged rats compared with the control animals. DIZE treatment improved cardiac hypertrophy and the expression of genes.

CONCLUSIONS

Overall, DIZE treatment significantly reversed the downregulation of PINK1, Mfn2, and Drp1. Moreover, DIZE significantly inhibited apoptosis though improving the gene expression of Bax and Bcl-2 in the heart. DIZE is effective in reducing cardiac hypertrophy induced aging through regulating mitochondrial dynamics, mitophagy and apoptosis.

GL261 glioblastoma induces delayed body weight gain and stunted skeletal muscle growth in young mice

Introduction

The survival rate for children and adolescents has increased to over 85%. However, there is limited understanding of the impact of pediatric cancers on muscle development and physiology. Given that brain tumors alone account for 26% of all pediatric cancers, this study aimed to investigate the skeletal muscle consequences of tumor growth in young mice.

Methods

C2C12 myotubes were co-cultured with GL261 murine glioblastoma cells to assess myotube size. GL261 cells were then injected subcutaneously into 4-week-old male C57BL/6J mice. Animals were euthanized 28 days post-GL261 implantation. Muscle function was tested in vivo and ex vivo . Muscle protein synthesis was measured via the SUnSET method, and gene/protein expression levels were assessed via Western blotting and qPCR.

Results

In vitro , the C2C12 cultures exposed to GL261 exhibited myotube atrophy, consistent with a disrupted anabolic/catabolic balance. In vivo , carcass, heart, and fat mass were significantly reduced in the tumor-bearing mice. Skeletal muscle growth was impeded in the GL261 hosts, along with smaller muscle CSA. Both in vivo muscle torque and the ex vivo EDL muscle force were unchanged. At molecular level, the tumor hosts displayed reduced muscle protein synthesis and increased muscle protein ubiquitination, in disagreement with decreased muscle ubiquitin ligase mRNA expression.

Conclusions

Overall, we showed that GL261 tumors impact the growth of pediatric mice by stunting skeletal muscle development, decreasing muscle mass, reducing muscle fiber size, diminishing muscle protein synthesis, and altering protein catabolism signaling.

Hypothermia regulates mitophagy and apoptosis via PINK1/Parkin-VDAC 3 signaling pathway during oxygen-glucose deprivation/recovery injury

Post-cardiac arrest brain injury (PCABI), as the main cause of high mortality and long-term disability in patients, induces mitochondrial damage and cell apoptosis. Hypothermia is well-known as an effective neuroprotective therapy, but its underlying mechanisms deserve further exploration. Previous study has demonstrated that hypothermia provides neuroprotection via increasing PINK1/Parkin-mediated mitophagy. However, whether hypothermia can regulate both apoptosis and mitophagy through the PINK1/Parkin-VDAC3 signaling pathway or not. In this study, BV2 mouse microglial cells were cultured under oxygen-glucose deprivation for 6 h following reperfusion with or without hypothermia for 2-4 h. Cell viability was examined by trypan blue stain. Mitophagy was observed by transmission electron microscope. Mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (mPTP) opening were determined respectively by JC-1 staining and BBcellProbe M61 staining using a flow cytometer. Expression of mitophagy-related proteins (Cleaved PINK1, Parkin, SQSTM1/p62, Beclin-1, LC3B II/LC3B I), apoptosis-related proteins (Bcl-2, Cytochrome C, caspase-3, cleaved caspase3) and VDAC3 were assessed using western blot analysis and quantitative real-time PCR. The interaction between Parkin and VDAC3 was confirmed by immunofluorescence colocalization. The results showed that hypothermia alleviated MMP damage, inhibited mPTP opening, then decreased cell apoptosis and activated mitophagy at 2 h after temperature intervention, which might be mediated by the PINK1/Parkin-VDAC3 signaling pathway. Moreover, the effects of hypothermia were reduced or reversed at 4 h after temperature intervention. In conclusion, the potential mechanisms of hypothermia during oxygen-glucose deprivation/recovery could be summarized as follows:1) At 2 h after temperature intervention, hypothermia provided neuroprotective effects via promoting mitophagy and reducing apoptosis through activating the PINK1/Parkin-VDAC3 signaling pathway. 2) The curative effect of hypothermia was timeliness. At 4 h after temperature intervention, hypothermia aggravated apoptosis through inhibiting Parkin recruitment to mitochondria and aggravating the release of Cyt C through open mPTP.

MCU complex: Exploring emerging targets and mechanisms of mitochondrial physiology and pathology

BACKGROUND

Globally, the onset and progression of multiple human diseases are associated with mitochondrial dysfunction and dysregulation of Ca2+ uptake dynamics mediated by the mitochondrial calcium uniporter (MCU) complex, which plays a key role in mitochondrial dysfunction. Despite relevant studies, the underlying pathophysiological mechanisms have not yet been fully elucidated.

AIM OF REVIEW

This article provides an in-depth analysis of the current research status of the MCU complex, focusing on its molecular composition, regulatory mechanisms, and association with diseases. In addition, we conducted an in-depth analysis of the regulatory effects of agonists, inhibitors, and traditional Chinese medicine (TCM) monomers on the MCU complex and their application prospects in disease treatment. From the perspective of medicinal chemistry, we conducted an in-depth analysis of the structure-activity relationship between these small molecules and MCU and deduced potential pharmacophores and binding pockets. Simultaneously, key structural domains of the MCU complex in Homo sapiens were identified. We also studied the functional expression of the MCU complex in Drosophila, Zebrafish, and Caenorhabditis elegans. These analyses provide a basis for exploring potential treatment strategies targeting the MCU complex and provide strong support for the development of future precision medicine and treatments.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The MCU complex exhibits varying behavior across different tissues and plays various roles in metabolic functions. It consists of six MCU subunits, an essential MCU regulator (EMRE), and solute carrier 25A23 (SLC25A23). They regulate processes, such as mitochondrial Ca2+ (mCa2+) uptake, mitochondrial adenosine triphosphate (ATP) production, calcium dynamics, oxidative stress (OS), and cell death. Regulation makes it a potential target for treating diseases, especially cardiovascular diseases, neurodegenerative diseases, inflammatory diseases, metabolic diseases, and tumors.

Canonical and noncanonical autophagy: involvement in Parkinson's disease

Autophagy is the major degradation process in cells and is involved in a variety of physiological and pathological functions. While macroautophagy, which employs a series of molecular cascades to form ATG8-coated double membrane autophagosomes for degradation, remains the well-known type of canonical autophagy, microautophagy and chaperon-mediated autophagy have also been characterized. On the other hand, recent studies have focused on the functions of autophagy proteins beyond intracellular degradation, including noncanonical autophagy, also known as the conjugation of ATG8 to single membranes (CASM), and autophagy-related extracellular secretion. In particular, CASM is unique in that it does not require autophagy upstream mechanisms, while the ATG8 conjugation system is involved in a manner different from canonical autophagy. There have been many reports on the involvement of these autophagy-related mechanisms in neurodegenerative diseases, with Parkinson's disease (PD) receiving particular attention because of the important roles of several causative and risk genes, including LRRK2. In this review, we will summarize and discuss the contributions of canonical and noncanonical autophagy to cellular functions, with a special focus on the pathogenesis of PD.

Molecular regulation of mitophagy signaling in tumor microenvironment and its targeting for cancer therapy

Aberrations emerging in mitochondrial homeostasis are restrained by mitophagy to control mitochondrial integrity, bioenergetics signaling, metabolism, oxidative stress, and apoptosis. The mitophagy-accompanied mitochondrial processes that occur in a dysregulated condition act as drivers for cancer occurrence. In addition, the enigmatic nature of mitophagy in cancer cells modulates the cellular proteome, creating challenges for therapeutic interventions. Several reports found the role of cellular signaling pathways in cancer to modulate mitophagy to mitigate stress, immune checkpoints, energy demand, and cell death. Thus, targeting mitophagy to hinder oncogenic intracellular signaling by promoting apoptosis, in hindsight, might have an edge against cancer. This review highlights the receptors and adaptors, and the involvement of many proteins in mitophagy and their role in oncogenesis. It also provides insight into using mitophagy as a potential target for therapeutic intervention in various cancer types.

Protective effects of olive oil against cardiac aging through mitophagy and apoptosis

Cardiac mitochondrial dysfunction is an important feature of aged heart. However, there is still no potent agent to ameliorate cardiac function abnormalities in aged hosts. Olive oil (OLO), containing monounsaturated fatty acids, has diverse protective effects on the cardiovascular system, including anti-diabetic, anti-inflammatory, and anti-hypertensive effects. We evaluated the beneficial impacts of OLO against aging-related cardiac dysfunction. Wistar rats were randomly allotted into three groups with eight rats, including control, aged rats receiving D-galactose (D-GAL), and aged rats administrated with D-galactose plus OLO (D-GAL + OLO). Aged animals were received D-GAL at a dose of 150.00 mg kg-1 daily through intra-peritoneal injection for aging induction. The animals in D-GAL + OLO group were co-administrated with oral OLO at a dose of 1.00 mL kg-1 by gavage feeding daily. The administration term was eight weeks. A histological examination of heart tissue was performed. The heart tissues were also harvested to assay the oxidative stress and molecular parameters. The aged animals showed cardiac hypertrophy, increased malondialdehyde level and Bax expression, and reduced mitofusin 2, phosphatase and tensin homologue-induced putative kinase 1, dynamin-related protein 1, and Bcl2 expressions in comparison with the control animals. The OLO treatment ameliorated all these parameters. Overall, OLO could improve cardiac aging through reducing oxidative stress, enhancing genes mediated mitophagy, and improving genes mediated apoptosis in the heart.

NERINE reveals rare variant associations in gene networks across multiple phenotypes and implicates an SNCA-PRL-LRRK2 subnetwork in Parkinson's disease

Gene networks encapsulate biological knowledge, often linked to polygenic diseases. While model system experiments generate many plausible gene networks, validating their role in human phenotypes requires evidence from human genetics. Rare variants provide the most straightforward path for such validation. While single-gene analyses often lack power due to rare variant sparsity, expanding the unit of association to networks offers a powerful alternative, provided it integrates network connections. Here, we introduce NERINE, a hierarchical model-based association test that integrates gene interactions that integrates gene interactions while remaining robust to network inaccuracies. Applied to biobanks, NERINE uncovers compelling network associations for breast cancer, cardiovascular diseases, and type II diabetes, undetected by single-gene tests. For Parkinson's disease (PD), NERINE newly substantiates several GWAS candidate loci with rare variant signal and synergizes human genetics with experimental screens targeting cardinal PD pathologies: dopaminergic neuron survival and alpha-synuclein pathobiology. CRISPRi-screening in human neurons and NERINE converge on PRL, revealing an intraneuronal α-synuclein/prolactin stress response that may impact resilience to PD pathologies.

A potential therapeutic approach for ulcerative colitis: targeted regulation of mitochondrial dynamics and mitophagy through phytochemicals

Mitochondria are important organelles that regulate cellular energy and biosynthesis, as well as maintain the body's response to environmental stress. Their dynamics and autophagy influence occurrence of cellular function, particularly under stressful conditions. They can generate reactive oxygen species (ROS) which is a major contributor to inflammatory diseases such as ulcerative colitis (UC). In this review, we discuss the key effects of mitochondrial dynamics and mitophagy on the pathogenesis of UC, with a particular focus on the cellular energy metabolism, oxidative stress, apoptosis, and immunoinflammatory activities. The therapeutic efficacy of existing drugs and phytochemicals targeting the mitochondrial pathway are discussed to reveal important insights for developing therapeutic strategies for treating UC. In addition, new molecular checkpoints with therapeutic potential are identified. We show that the integration of mitochondrial biology with the clinical aspects of UC may generate ideas for enhancing the clinical management of UC.

Mechanistic Evaluation of miRNAs and Their Targeted Genes in the Pathogenesis and Therapeutics of Parkinson's Disease

MicroRNA (miRNA) are usually 18-25 nucleotides long non-coding RNA targeting post-transcriptional regulation of genes involved in various biological processes. The function of miRNA is essential for maintaining a homeostatic cellular condition, regulating autophagy, cellular motility, and inflammation. Dysregulation of miRNA is responsible for multiple disorders, including neurodegeneration, which has emerged as a severe problem in recent times and has verified itself as a life-threatening condition that can be understood by the continuous destruction of neurons affecting various cognitive and motor functions. Parkinson's disease (PD) is the second most common, permanently debilitating neurodegenerative disorder after Alzheimer's, mainly characterized by uncontrolled tremor, stiffness, bradykinesia or akinesia (slowness in movement), and post-traumatic stress disorder. PD is mainly caused by the demolition of the primary dopamine neurotransmitter secretory cells and dopaminergic or dopamine secretory neurons in the substantia nigra pars compacta of the midbrain, which are majorly responsible for motor functions. In this study, a systematic evaluation of research articles from year 2017 to 2022 was performed on multiple search engines, and lists of miRNA being dysregulated in PD in different body components were generated. This study highlighted miR-7, miR-124, miR-29 family, and miR-425, showing altered expression levels during PD's progression, further regulating the expression of multiple genes responsible for PD.

VDAC1: A Key Player in the Mitochondrial Landscape of Neurodegeneration

Voltage-Dependent Anion Channel 1 (VDAC1) is a mitochondrial outer membrane protein that plays a crucial role in regulating cellular energy metabolism and apoptosis by mediating the exchange of ions and metabolites between mitochondria and the cytosol. Mitochondrial dysfunction and oxidative stress are central features of neurodegenerative diseases. The pivotal functions of VDAC1 in controlling mitochondrial membrane permeability, regulating calcium balance, and facilitating programmed cell death pathways, position it as a key determinant in the delicate balance between neuronal viability and degeneration. Accordingly, increasing evidence suggests that VDAC1 is implicated in the pathophysiology of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and others. This review summarizes the current findings on the contribution of VDAC1 to neurodegeneration, focusing on its interactions with disease-specific proteins, such as amyloid-β, α-synuclein, and mutant SOD1. By unraveling the complex involvement of VDAC1 in neurodegenerative processes, this review highlights potential avenues for future research and drug development aimed at alleviating mitochondrial-related neurodegeneration.

FXR-regulated COX6A2 triggers mitochondrial apoptosis of pancreatic β-cell in type 2 diabetes

Pancreatic β-cell apoptosis plays a crucial role in the development of type 2 diabetes. Cytochrome c oxidase subunit 6A2 (COX6A2) and Farnesoid X Receptor (FXR) have been identified in pancreatic β-cells, however, whether they are involved in β-cell apoptosis is unclear. Here, we sought to investigate the role of FXR-regulated COX6A2 in diabetic β-cell apoptosis. We found that COX6A2 expression was increased in islets from diabetic animals, whereas FXR expression was suppressed. Notably, overexpression of COX6A2 facilitated β-cell apoptosis, whereas its deficiency attenuated this process and ameliorates type 2 diabetes, suggesting a pro-apoptotic role of COX6A2 in β-cells. Mechanistically, increased COX6A2 interacted with and enhanced the expression of voltage-dependent anion channel 1 (VDAC1), thereby promoting the mitochondrial translocation of Bax, leading to the release of cytochrome c from the mitochondria to the cytoplasm and ultimately causing β-cell apoptosis. Moreover, FXR negatively regulated COX6A2 expression through the inhibition of histone acetyltransferase p300 occupancy, diminishing histone H3 acetylation at lysine 27 on the Cox6a2 promoter. Furthermore, the deficiency of FXR intensified β-cell apoptosis under diabetic situations. Thus, it is probable that in diabetogenic environments, reduced FXR expression contributes to enhanced COX6A2 expression, culminating in β-cell apoptosis. These findings emphasize the essential involvement of the FXR/p300 pathway-controlled COX6A2 in β-cell apoptosis, revealing a previously undiscovered mechanism underlying diabetic β-cell apoptosis.

Rotenone exposure causes features of Parkinson`s disease pathology linked with muscle atrophy in developing zebrafish embryo

Parkinson's disease (PD) is associated with both genetic and environmental factors; however, sporadic forms of PD account for > 90 % of cases, and PD prevalence has doubled in the past 25 years. Depending on the importance of the environmental factors, various neurotoxins are used to induce PD both in vivo and in vitro. Unlike other neurodegenerative diseases, PD can be induced in vivo using specific neurotoxic chemicals. However, no chemically induced PD model is available because of the sporadic nature of PD. Rotenone is a pesticide that accelerates the induction of PD and exhibits the highest toxicity in fish, unlike other pesticides. Therefore, in this study, we aimed to establish a model exhibiting PD pathologies such as dysfunction of DArgic neuron, aggregation of ɑ-synuclein, and behavioral abnormalities, which are known features of PD pathology, by rotenone exposure at an environmentally relevant concentration (30 nM) in developing zebrafish embryos. Our results provide direct evidence for the association between PD and muscle degeneration by confirming rotenone-induced muscle atrophy. Therefore, we conclude that the rotenone-induced model presents non-motor and motor defects with extensive studies related to muscle atrophy.

Discovery of Balasubramide Derivative with Tissue-Specific Anti-Inflammatory Activity Against Acute Lung Injury by Targeting VDAC1

Macrophage-mediated inflammatory responses including pyroptosis are involved in the pathogenesis of sepsis and acute lung injury (ALI), for which there are currently no effective therapeutic treatments. The natural product (+)-Balasubramide is an eight-membered lactam compound extracted from the leaves of the Sri Lanka plant Clausena Indica and has shown anti-inflammatory activities, but its poor pharmacokinetic properties limit its further application for ALI. In this study, a compound (+)3C-20 is discovered with improved both pharmacokinetic properties and anti-inflammatory activity from a series of (+)-Balasubramide derivatives. The compound (+)3C-20 exhibits a markedly enhanced inhibitory effect against LPS-induced expressions of pro-inflammatory factors in mouse macrophages and human PBMCs from ALI patients and shows a preferable lung tissue distribution in mice. (+)3C-20 remarkably attenuates LPS-induced ALI through lung tissue-specific anti-inflammatory actions. Mechanistically, a chemical proteomics study shows that (+)3C-20 directly binds to mitochondrial VDAC1 and inhibits VDAC1 oligomerization to block mtDNA release, further preventing NLRP3 inflammasome activation. These findings identify (+)3C-20 as a novel VDAC1 inhibitor with promising therapeutic potential for ALI associated with inflammation.

Therapeutic potential of Parkin and its regulation in Parkinson's disease

Parkinson's disease (PD) is a debilitating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the midbrain substantia nigra, resulting in motor and non-motor symptoms. While the exact etiology of PD remains elusive, a growing body of evidence suggests that dysfunction in the parkin protein plays a pivotal role in the pathogenesis of the disease. Parkin is an E3 ubiquitin ligase that ubiquitinates substrate proteins to control a number of crucial cellular processes including protein catabolism, immune response, and cellular apoptosis.While autosomal recessive mutations in the PARK2 gene, which codes for parkin, are linked to an inherited form of early-onset PD, heterozygous mutations in PARK2 have also been reported in the more commonly occurring sporadic PD cases. Impairment of parkin's E3 ligase activity is believed to play a pathogenic role in both familial and sporadic forms of PD.This article provides an overview of the current understanding of the mechanistic basis of parkin's E3 ligase activity, its major physiological role in controlling cellular functions, and how these are disrupted in familial and sporadic PD. The second half of the manuscript explores the currently available and potential therapeutic strategies targeting parkin structure and/or function in order to slow down or mitigate the progressive neurodegeneration in PD.

Mechanistic exploration of ubiquitination-mediated pathways in cerebral ischemic injury

The ubiquitin-proteasome system (UPS) plays a pivotal role in regulating protein homeostasis and cellular processes, including protein degradation, trafficking, DNA repair, and cell signaling. During cerebral ischemia, ischemic conditions profoundly disrupt UPS activity, leading to proteasomal dysfunction and the accumulation of abnormal proteins. This imbalance contributes to neuronal injury and cell death observed in ischemic stroke. The UPS is intricately linked to various signaling pathways crucial for neuronal survival, inflammation, and cellular stress response, such as NF-κB, TRIM, TRIP, JAK-STAT, PI3K/Akt, and ERK1/2. Alterations in the ubiquitination process can significantly impact the activation and regulation of these pathways, exacerbating ischemic brain injury. Therapeutic approaches targeting the UPS in cerebral ischemia aim to rebalance protein levels, reduce proteotoxic stress, and mitigate neuronal injury. Strategies include proteasome inhibition, targeting specific ubiquitin ligases and deubiquitinating enzymes, and modulating ubiquitination-mediated regulation of key signaling pathways implicated in ischemia-induced pathophysiology. Therefore, the present review discusses the molecular mechanisms underlying UPS dysfunction in ischemic stroke is crucial for developing effective therapeutic interventions. Modulating ubiquitination-mediated pathways through therapeutic interventions targeting specific UPS components holds significant promise for mitigating ischemic brain injury and promoting neuroprotection and functional recovery in patients with cerebral ischemia.

Can stable introns and noncoding RNAs be harnessed to improve health through activation of mitohormesis?

Ever since their introduction a decade ago, stable introns, a type of noncoding (nc)RNAs, are found to be key players in different important cellular processes acting through regulation of gene expression and feedback loops to maintain cellular homeostasis. Despite being commonly regarded as useless byproducts, recent studies in yeast suggested that stable introns are essential for cell survivability under starvation. In Drosophila, we found that a stable intron, sisR-1, has a direct effect in regulating mitochondrial dynamics during short-term fasting and subsequently improved overall oocyte quality. We speculated that the beneficial effects implicated by sisR-1 is through the activation of mitohormesis, an interesting phenomenon in mitochondrial biology. Mitohormesis is suggested to improve health span and lifespan of cells and organisms, but the involvement of ncRNAs is not well-documented. Here, we discuss the potential role of sisR-1 and other ncRNAs in activating mitohormesis and the possible applications in improving cellular and organismal health.

E3 ubiquitin ligase TRIM31 alleviates dopaminergic neurodegeneration by promoting proteasomal degradation of VDAC1 in Parkinson's Disease model

Mitochondrial dysfunction plays a pivotal role in the pathogenesis of Parkinson's disease (PD). As a mitochondrial governor, voltage-dependent anion channel 1 (VDAC1) is critical for cell survival and death signals and implicated in neurodegenerative diseases. However, the mechanisms of VDAC1 regulation are poorly understood and the role of tripartite motif-containing protein 31 (TRIM31), an E3 ubiquitin ligase which is enriched in mitochondria, in PD remains unclear. In this study, we found that TRIM31-/- mice developed age associated motor defects and dopaminergic (DA) neurodegeneration spontaneously. In addition, TRIM31 was markedly reduced both in nigrostriatal region of PD mice induced by MPTP and in SH-SY5Y cells stimulated by MPP+. TRIM31 deficiency significantly aggravated DA neurotoxicity induced by MPTP. Mechanistically, TRIM31 interacted with VDAC1 and catalyzed the K48-linked polyubiquitination to degrade it through its E3 ubiquitin ligase activity. In conclusion, we demonstrated for the first time that TRIM31 served as an important regulator in DA neuronal homeostasis by facilitating VDAC1 degradation through the ubiquitin-proteasome pathway. Our study identified TRIM31 as a novel potential therapeutic target and pharmaceutical intervention to the interaction between TRIM31 and VDAC1 may provide a promising strategy for PD.

Mitophagy: insights into its signaling molecules, biological functions, and therapeutic potential in breast cancer

Mitophagy, a form of selective autophagy that removes damaged or dysfunctional mitochondria, plays a crucial role in maintaining mitochondrial and cellular homeostasis. Recent findings suggest that defective mitophagy is closely associated with various diseases, including breast cancer. Moreover, a better understanding of the multifaceted roles of mitophagy in breast cancer progression is crucial for the treatment of this disease. Here, we will summarize the molecular mechanisms of mitophagy process. In addition, we highlight the expression patterns and roles of mitophagy-related signaling molecules in breast cancer progression and the potential implications of mitophagy for the development of breast cancer, aiming to provide better therapeutic strategies for breast cancer treatment.

Activity-Based Acylome Profiling with N-(Cyanomethyl)-N-(phenylsulfonyl)amides for Targeted Lysine Acylation and Post-Translational Control of Protein Function in Cells

Lysine acylations are ubiquitous and structurally diverse post-translational modifications that vastly expand the functional heterogeneity of the human proteome. Hence, the targeted acylation of lysine residues has emerged as a strategic approach to exert biomimetic control over the protein function. However, existing strategies for targeted lysine acylation in cells often rely on genetic intervention, recruitment of endogenous acylation machinery, or nonspecific acylating agents and lack methods to quantify the magnitude of specific acylations on a global level. In this study, we develop activity-based acylome profiling (ABAP), a chemoproteomic strategy that exploits elaborate N-(cyanomethyl)-N-(phenylsulfonyl)amides and lysine-centric probes for site-specific introduction and proteome-wide mapping of posttranslational lysine acylations in human cells. Harnessing this framework, we quantify various artificial acylations and rediscover numerous endogenous lysine acylations. We validate site-specific acetylation of target lysines and establish a structure-activity relationship for N-(cyanomethyl)-N-(phenylsulfonyl)amides in proteins from diverse structural and functional classes. We identify paralog-selective chemical probes that acetylate conserved lysines within interferon-stimulated antiviral RNA-binding proteins, generating de novo proteoforms with obstructed RNA interactions. We further demonstrate that targeted acetylation of a key enzyme in retinoid metabolism engenders a proteoform with a conformational change in the protein structure, leading to a gain-of-function phenotype and reduced drug potency. These findings underscore the versatility of our strategy in biomimetic control over protein function through targeted delivery and global profiling of endogenous and artificial lysine acylations, potentially advancing therapeutic modalities and our understanding of biological processes orchestrated by these post-translational modifications.

Siah3 acts as a physiological mitophagy suppressor that facilitates axonal degeneration

Mitophagy eliminates dysfunctional mitochondria, and defects in this cellular housekeeping mechanism are implicated in various age-related diseases. Here, we found that mitophagy suppression by the protein Siah3 promoted developmental axonal remodeling in mice. Siah3-deficient mice displayed increased peripheral sensory innervation. Cultured Siah3-deficient sensory neurons exhibited delays in both axonal degeneration and caspase-3 activation in response to withdrawal of nerve growth factor. Mechanistically, Siah3 was transcriptionally induced by the loss of trophic support and formed a complex with the cytosolic E3 ubiquitin ligase parkin, a core component of mitophagy, in transfected cells. Axons of Siah3-deficient neurons mounted profound mitophagy upon initiation of degeneration but not under basal conditions. Neurons lacking both Siah3 and parkin did not exhibit the delay in trophic deprivation-induced axonal degeneration or the induction of axonal mitophagy that was seen in Siah3-deficient neurons. Our findings reveal that mitophagy regulation acts as a gatekeeper of a physiological axon elimination program.

Investigating the interplay between mitophagy and diabetic neuropathy: Uncovering the hidden secrets of the disease pathology

Mitophagy, the cellular process of selectively eliminating damaged mitochondria, plays a crucial role in maintaining metabolic balance and preventing insulin resistance, both key factors in type 2 diabetes mellitus (T2DM) development. When mitophagy malfunctions in diabetic neuropathy, it triggers a cascade of metabolic disruptions, including reduced energy production, increased oxidative stress, and cell death, ultimately leading to various complications. Thus, targeting mitophagy to enhance the process may have emerged as a promising therapeutic strategy for T2DM and its complications. Notably, plant-derived compounds with β-cell protective and mitophagy-stimulating properties offer potential as novel therapeutic agents. This review highlights the intricate mechanisms linking mitophagy dysfunction to T2DM and its complications, particularly neuropathy, elucidating potential therapeutic interventions for this debilitating disease.

Targeting the PINK1/Parkin pathway: A new perspective in the prevention and therapy of diabetic retinopathy

Diabetic retinopathy (DR) is a microvascular complication of diabetes characterized by neurovascular impairment of the retina. The dysregulation of the mitophagy process occurs before apoptotic cell death and the appearance of vascular damage. In particular, mitochondrial alterations happen during DR development, supporting the hypothesis that mitophagy is negatively correlated to disease progression. This process is mainly regulated by the PTEN-induced putative kinase protein 1 (PINK1)/Parkin pathway whose activation promotes mitophagy. In this review, we will summarize the evidence reported in the literature demonstrating the involvement of the PINK1/Parkin pathway in diabetic retinopathy-induced retinal degeneration.

Suppression of neuronal CDK9/p53/VDAC signaling provides bioenergetic support and improves post-stroke neuropsychiatric outcomes

Bioenergy decline occurs with reperfusion following acute ischemic stroke. However, the molecular mechanisms that limit energy metabolism and their impact on post-stroke cognitive and emotional complications are still unclear. In the present study, we demonstrate that the p53 transcriptional response is responsible for neuronal adenosine triphosphate (ATP) deficiency and progressively neuropsychiatric disturbances, involving the downregulation of mitochondrial voltage-dependent anion channels (VDACs). Neuronal p53 transactivated the promoter of microRNA-183 (miR-183) cluster, thereby upregulating biogenesis of miR-183-5p (miR-183), miR-96-5p (miR-96), and miR-182-5p. Both miR-183 and miR-96 directly targeted and post-transcriptionally suppressed VDACs. Neuronal ablation of p53 protected against ATP deficiency and neurological deficits, whereas post-stroke rescue of miR-183/VDAC signaling reversed these benefits. Interestingly, cyclin-dependent kinase 9 (CDK9) was found to be enriched in cortical neurons and upregulated the p53-induced transcription of the miR-183 cluster in neurons after ischemia. Post-treatment with the CDK9 inhibitor oroxylin A promoted neuronal ATP production mainly through suppressing the miR-183 cluster/VDAC axis, further improved long-term sensorimotor abilities and spatial memory, and alleviated depressive-like behaviors in mice following stroke. Our findings reveal an intrinsic CDK9/p53/VDAC pathway that drives neuronal bioenergy decline and underlies post-stroke cognitive impairment and depression, thus highlighting the therapeutic potential of oroxylin A for better outcomes.

The role and mechanism of VDAC1 in type 2 diabetes: An underestimated target of environmental pollutants

Type 2 diabetes (T2D) is a chronic metabolic disease that accounts for more than 90% of diabetic patients. Its main feature is hyperglycemia due to insulin resistance or insulin deficiency. With changes in diet and lifestyle habits, the incidence of T2D in adolescents has burst in recent decades. The deterioration in the exposure to the environmental pollutants further aggravates the prevalence of T2D, and consequently, it imposes a significant economic burden. Therefore, early prevention and symptomatic treatment are essential to prevent diabetic complications. Mitochondrial number and electron transport chain activity are decreased in the patients with T2D. Voltage-Dependent Anion Channel 1 (VDAC1), as a crucial channel protein on the outer membrane of mitochondria, regulates signal transduction between mitochondria and other cellular components, participating in various biological processes. When VDAC1 exists in oligomeric form, it additionally facilitates the entry and exit of macromolecules into and from mitochondria, modulating insulin secretion. We summarize and highlight the interplay between VDAC1 and T2D, especially in the environmental pollutants-related T2D, shed light on the potential therapeutic implications of targeting VDAC1 monomers and oligomers, providing a new possible target for the treatment of T2D.

Uncovering the mechanisms of host mitochondrial cardiolipin release in syphilis: Insights from human microvascular endothelial cells

The release of host mitochondrial cardiolipin is believed to be the main factor that contributes to the production of anti-cardiolipin antibodies in syphilis. However, the precise mechanism by which mitochondria release cardiolipin in this context remains elusive. This study aimed to elucidate the mechanisms underlying mitochondrial cardiolipin release in syphilis. We conducted a cardiolipin quantitative assay and immunofluorescence analysis to detect mitochondrial cardiolipin release in human microvascular endothelial cells (HMEC-1), with and without Treponema pallidum (Tp) infection. Furthermore, we explored apoptosis, a key mechanism for mitochondrial cardiolipin release. The potential mediator molecules were then analyzed through RNA-sequence and subsequently validated using in vitro knockout techniques mediated by CRISPR-Cas9 and pathway-specific inhibitors. Our findings confirm that live-Tp is capable of initiating the release of mitochondrial cardiolipin, whereas inactivated-Tp does not exhibit this capability. Additionally, apoptosis detection further supports the notion that the release of mitochondrial cardiolipin occurs independently of apoptosis. The RNA-sequencing results indicated that microtubule-associated protein2 (MAP2), an axonogenesis and dendrite development gene, was up-regulated in HMEC-1 treated with Tp, which was further confirmed in syphilitic lesions by immunofluorescence. Notably, genetic knockout of MAP2 inhibited Tp-induced mitochondrial cardiolipin release in HMEC-1. Mechanically, Tp-infection regulated MAP2 expression via the MEK-ERK-HES1 pathway, and MEK/ERK phosphorylation inhibitors effectively block Tp-induced mitochondrial cardiolipin release. This study demonstrated that the infection of live-Tp enhanced the expression of MAP2 via the MEK-ERK-HES1 pathway, thereby contributing to our understanding of the role of anti-cardiolipin antibodies in the diagnosis of syphilis.

PGK1 can affect the prognosis and development of bladder cancer

BACKGROUND

Previous studies have demonstrated that the glycolytic enzyme phosphoglycerate kinase 1 (PGK1) can promote tumor development. This study sought to investigate the specific role of PGK1 in bladder cancer (BLCA).

METHODS

Public databases and immunohistochemistry assays were utilized to analyze the expression of PGK1 in BLCA and its prognostic significance. Cell proliferation was assessed through CCK-8 and colony formation assays, while the level of metastasis was evaluated using transwell migration experiments. Additionally, IC50 experiments were conducted to assess the impact of PGK1 on cisplatin sensitivity.

RESULTS

The mRNA and protein expression levels of PGK1 were significantly upregulated in BLCA. Cox proportional hazards model analysis revealed that PGK1 and T stage were independent prognostic factors for BLCA patients. Both CCK-8 and colony assays demonstrated that PGK1 promotes proliferation. Furthermore, a positive correlation was observed between PGK1 and Ki67, a proliferation index. Transwell migration assays confirmed the ability of PGK1 to enhance metastasis. Finally, PGK1 increased the IC50 associated with cisplatin treatment in BLCA.

CONCLUSION

Collectively, these findings suggest that PGK1 may hold clinical value in predicting BLCA prognosis and improving the outcomes of this patient population.

Construction of a mitophagy-related prognostic signature for predicting prognosis and tumor microenvironment in lung adenocarcinoma

Background

Mitophagy is the selective degradation of mitochondria by autophagy. It becomes increasingly clear that mitophagy pathways are important for cancer cells to adapt to their high-energy needs. However, which genes associated with mitophagy could be used to prognosis cancer is unknown.

Methods

We created a clinical prognostic model using mitophagy-related genes (MRGs) in lung adenocarcinoma (LUAD) patients for the first time, and we employed bioinformatics methods to search for biomarkers that affect the progression and prognosis of LUAD. Transcriptome data for LUAD were obtained from The Cancer Genome Atlas (TCGA) database, and additional expression data from LUAD patients were sourced from the Gene Expression Omnibus (GEO) database. Furthermore, 25 complete MRGs were identified based on annotations from the MSigDB database.

Results

A comparison of the mitophagy scores between the groups with high and low scores was done using receiver operating characteristic (ROC) curves, which also revealed the differential gene expression patterns between the two groups. Using Kaplan-Meier analysis, two prognostic MRGs from the groups with high and low mitophagy scores were identified: TOMM40 and VDAC1. Using univariate and multivariate Cox regression, the relationship between the expression levels of these two genes and prognostic clinical features of LUAD was examined further.The prognosis of LUAD patients was shown to be significantly correlated (P < 0.05) with the expression levels of these two genes.

Conclusions

Our prognostic model would improve the prognosis of LUAD and guide clinical treatments.

Novel Insights into Parkin-Mediated Mitochondrial Dysfunction and "Mito-Inflammation" in α-Synuclein Toxicity. The Role of the cGAS-STING Signalling Pathway

The prevalence of age-related neurodegenerative diseases, such as Parkinson's disease (PD) and related disorders continues to grow worldwide. Increasing evidence links intracellular inclusions of misfolded alpha-synuclein (α-syn) aggregates, so-called Lewy bodies (LB) and Lewy neuritis, to the progressive pathology of PD and other synucleinopathies. Our previous findings established that α-syn oligomers induce S-nitrosylation and deregulation of the E3-ubiquitin ligase Parkin, leading to mitochondrial disturbances in neuronal cells. The accumulation of damaged mitochondria as a consequence, together with the release of mitochondrial-derived damage-associated molecular patterns (mtDAMPs) could activate the innate immune response and induce neuroinflammation ("mito-inflammation"), eventually accelerating neurodegeneration. However, the molecular pathways that transmit pro-inflammatory signals from damaged mitochondria are not well understood. One of the proposed pathways could be the cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) (cGAS-STING) pathway, which plays a pivotal role in modulating the innate immune response. It has recently been suggested that cGAS-STING deregulation may contribute to the development of various pathological conditions. Especially, its excessive engagement may lead to neuroinflammation and appear to be essential for the development of neurodegenerative brain diseases, including PD. However, the precise molecular mechanisms underlying cGAS-STING pathway activation in PD and other synucleinopathies are not fully understood. This review focuses on linking mitochondrial dysfunction to neuroinflammation in these disorders, particularly emphasizing the role of the cGAS-STING signaling. We propose the cGAS-STING pathway as a critical driver of inflammation in α-syn-dependent neurodegeneration and hypothesize that cGAS-STING-driven "mito-inflammation" may be one of the key mechanisms promoting the neurodegeneration in PD. Understanding the molecular mechanisms of α-syn-induced cGAS-STING-associated "mito-inflammation" in PD and related synucleinopathies may contribute to the identification of new targets for the treatment of these disorders.

The small yeast GTPase Rho5 requires specific mitochondrial outer membrane proteins for translocation under oxidative stress and interacts with the VDAC Por1

Yeast Rho5 is a small GTPase which mediates the response to nutrient and oxidative stress, and triggers mitophagy and apoptosis. We here studied the rapid translocation of a GFP-tagged Rho5 to mitochondria under such stress conditions by live-cell fluorescence microscopy in the background of strains lacking different mitochondrial outer membrane proteins (MOMP). Fun14, Msp1 and Alo1 were found to be required for efficient recruitment of the GTPase, whereas translocation of Dck1 and Lmo1, the subunits of its dimeric GDP/GTP exchange factor (GEF), remained unaffected. An influence of the voltage-dependent anion channel (VDAC) Por1 on the association of GFP-Rho5 with mitochondria under oxidative stress conditions appeared to be strain-dependent. However, epistasis analyses and bimolecular fluorescence complementation (BiFC) studies indicate a genetic and physical interaction. All four strains lacking a single MOMP were investigated for their effect on mitophagy.

Mechanisms and implications of podocyte autophagy in chronic kidney disease

Autophagy is a protective mechanism through which cells degrade and recycle proteins and organelles to maintain cellular homeostasis and integrity. An accumulating body of evidence underscores the significant impact of dysregulated autophagy on podocyte injury in chronic kidney disease (CKD). In this review, we provide a comprehensive overview of the diverse types of autophagy and their regulation in cellular homeostasis, with a specific emphasis on podocytes. Furthermore, we discuss recent findings that focus on the functional role of different types of autophagy during podocyte injury in chronic kidney disease. The intricate interplay between different types of autophagy and podocyte health requires further research, which is critical for understanding the pathogenesis of CKD and developing targeted therapeutic interventions.

SIRT3 and RORα are two prospective targets against mitophagy during simulated ischemia/reperfusion injury in H9c2 cells

Autophagy during myocardial ischemia/reperfusion (MI/R) exacerbates cardiomyocyte injury. Melatonin (Mel) alleviates myocardial damage by regulating mitochondrial function and mitophagy, but the role of mitophagy in melatonin-induced cardioprotection remains unclear. This study aimed to explore the roles of sirtuin3 (SIRT3) and retinoid-related orphan nuclear receptor-α (RORα) in mitophagy during simulated ischemia reperfusion (SIR) in H9c2 cells. Our data showed that mitophagy was excessively activated after SIR injury, which was consistent with reduced cell survival, enhanced oxidative responses and mitochondrial dysfunction in H9c2 myocytes. Melatonin greatly enhanced cell viability, reduced oxidative stress and improved mitochondrial function. The effects of melatonin protection were involved in excessive mitophagy inhibition, as demonstrated by the reduced levels of mitophagy-linked proteins, including Parkin, Beclin1, NIX and BNIP3, and the LC3 II/LC3 I ratio and elevations in p62. Additionally, the decreases in SIRT3 and RORα in H9c2 myocytes after SIR were reversed by melatonin, and the above effects of melatonin were eliminated by small interfering RNA (siRNA)-mediated knockdown of SIRT3 and RORα. In brief, SIRT3 and RORα are two prospective targets in the cardioprotection of melatonin against mitophagy during SIR in H9c2 myocytes.

Global, site-resolved analysis of ubiquitylation occupancy and turnover rate reveals systems properties

Ubiquitylation regulates most proteins and biological processes in a eukaryotic cell. However, the site-specific occupancy (stoichiometry) and turnover rate of ubiquitylation have not been quantified. Here we present an integrated picture of the global ubiquitylation site occupancy and half-life. Ubiquitylation site occupancy spans over four orders of magnitude, but the median ubiquitylation site occupancy is three orders of magnitude lower than that of phosphorylation. The occupancy, turnover rate, and regulation of sites by proteasome inhibitors are strongly interrelated, and these attributes distinguish sites involved in proteasomal degradation and cellular signaling. Sites in structured protein regions exhibit longer half-lives and stronger upregulation by proteasome inhibitors than sites in unstructured regions. Importantly, we discovered a surveillance mechanism that rapidly and site-indiscriminately deubiquitylates all ubiquitin-specific E1 and E2 enzymes, protecting them against accumulation of bystander ubiquitylation. The work provides a systems-scale, quantitative view of ubiquitylation properties and reveals general principles of ubiquitylation-dependent governance.

The crude extract obtained from Cinnamomum macrostemon Hayata regulates oxidative stress and mitophagy in keratinocytes

Four ethanol fractionated crude extracts (EFCEs [A-D]) purified from the leaves of Cinnamomum macrostemon Hayata were screened for antioxidative effects and mitochondrial function in HaCaT cells. The higher cell viability indicated that EFCE C was mildly toxic. Under the treatment of 50 ng/mL EFCE C, the hydrogen peroxide (H2O2)-induced cytosolic and mitochondrial reactive oxygen species levels were reduced as well as the H2O2-impaired cell viability, mitochondrial membrane potential (MMP), ATP production, and mitochondrial mass. The conversion of globular mitochondria to tubular mitochondria is coincident with EFCE C-restored mitochondrial function. The mitophagy activator rapamycin showed similar effects to EFCE C in recovering the H2O2-impaired cell viability, MMP, ATP production, mitochondrial mass, and also mitophagic proteins such as PINK1, Parkin, LC3 II, and biogenesis protein PGC-1α. We thereby propose the application of EFCE C in the prevention of oxidative stress in skin cells.

G6PD maintains the VSMC synthetic phenotype and accelerates vascular neointimal hyperplasia by inhibiting the VDAC1-Bax-mediated mitochondrial apoptosis pathway

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) plays an important role in vascular smooth muscle cell (VSMC) phenotypic switching, which is an early pathogenic event in various vascular remodeling diseases (VRDs). However, the underlying mechanism is not fully understood.

METHODS

An IP‒LC‒MS/MS assay was conducted to identify new binding partners of G6PD involved in the regulation of VSMC phenotypic switching under platelet-derived growth factor-BB (PDGF-BB) stimulation. Co-IP, GST pull-down, and immunofluorescence colocalization were employed to clarify the interaction between G6PD and voltage-dependent anion-selective channel protein 1 (VDAC1). The molecular mechanisms involved were elucidated by examining the interaction between VDAC1 and apoptosis-related biomarkers, as well as the oligomerization state of VDAC1.

RESULTS

The G6PD level was significantly elevated and positively correlated with the synthetic characteristics of VSMCs induced by PDGF-BB. We identified VDAC1 as a novel G6PD-interacting molecule essential for apoptosis. Specifically, the G6PD-NTD region was found to predominantly contribute to this interaction. G6PD promotes VSMC survival and accelerates vascular neointimal hyperplasia by inhibiting VSMC apoptosis. Mechanistically, G6PD interacts with VDAC1 upon stimulation with PDGF-BB. By competing with Bax for VDAC1 binding, G6PD reduces VDAC1 oligomerization and counteracts VDAC1-Bax-mediated apoptosis, thereby accelerating neointimal hyperplasia.

CONCLUSION

Our study showed that the G6PD-VDAC1-Bax axis is a vital switch in VSMC apoptosis and is essential for VSMC phenotypic switching and neointimal hyperplasia, providing mechanistic insight into early VRDs.

The interplay of mitophagy, autophagy, and apoptosis in cisplatin-induced kidney injury: involvement of ERK signaling pathway

AKI induced by CP chemotherapy remains an obstacle during patient treatments. Extracellular signal-regulated protein kinases 1/2 (ERK), key participants in CP-induced nephrotoxicity, are suggested to be involved in the regulation of mitophagy, autophagy, and apoptosis. Human renal proximal tubular cells (HK-2) and BALB/cN mice were used to determine the role of ERK in CP-induced AKI. We found that active ERK is involved in cell viability reduction during apoptotic events but exerts a protective role in the early stages of treatment. Activation of ERK acts as a maintainer of the mitochondrial population and is implicated in mitophagy initiation but has no significant role in its conduction. In the late stages of CP treatment when ATP is deprived, general autophagy that requires ERK activation is initiated as a response, in addition to apoptosis activation. Furthermore, activation of ERK is responsible for the decrease in reserve respiratory capacity and controls glycolysis regulation during CP treatment. Additionally, we found that ERK activation is also required for the induction of NOXA gene and protein expression as well as FoxO3a nuclear translocation, but not for the regular ERK-induced phosphorylation of FoxO3a on Ser294. In summary, this study gives detailed insight into the involvement of ERK activation and its impact on key cellular processes at different time points during CP-induced kidney injury. Inhibitors of ERK activation, including Mirdametinib, are important in the development of new therapeutic strategies for the treatment of AKI in patients receiving CP chemotherapy.