The role of the mitochondrial protein VDAC1 in inflammatory bowel disease: a potential therapeutic target

Resveratrol targeting MDM2/P53/PUMA axis to inhibit colonocyte apoptosis in DSS-induced ulcerative colitis mice

Background

Resveratrol, a naturally occurring polyphenolic compound found in grapes, berries, and traditional medicinal plants like Polygonum cuspidatum, has been used for centuries in traditional medicine systems for its anti-inflammatory, antioxidant, and cardioprotective properties. Ulcerative colitis (UC), a chronic inflammatory bowel disease, is characterized by intestinal barrier disruption due to excessive colonocyte apoptosis, leading to increased permeability and inflammation. Targeting apoptosis is a critical therapeutic strategy for UC.

Aim of the study

This study aims to investigate the therapeutic potential of Resveratrol in ulcerative colitis (UC) by targeting excessive colonocyte apoptosis and intestinal barrier dysfunction. Specifically, we seek to elucidate the mechanisms through which Resveratrol modulates apoptosis-related pathways and evaluate its efficacy in restoring intestinal homeostasis and mitigating UC progression in both in vivo and in vitro models.

Materials and Methods

We used dextran sulfate sodium (DSS) to induce UC in a mouse model. Colonic damage was assessed through colonic length measurement, histological examination, and immunofluorescence staining. Single-cell sequencing was employed to explore changes in the colonic immune microenvironment and cellular signaling pathways after Resveratrol treatment. In vitro, colonocytes isolated from healthy mouse colonic tissue were exposed to TGF-β to induce apoptosis. DNA fragmentation, mitochondrial membrane potential, and annexin V/propidium iodide staining were used to assess apoptosis. Additionally, we employed an Adeno-Associated Virus system to overexpress MDM2 in the colon and evaluate its protective role in DSS-induced UC.

Results

Resveratrol treatment effectively repaired colonic damage in the UC mouse model by significantly increasing colon length, reducing inflammatory cell infiltration, and mitigating mucosal injury. Single-cell sequencing revealed that Resveratrol primarily targeted colonocytes, decreasing genes related to apoptosis and the P53 pathway. In vitro, Resveratrol reduced DNA fragmentation, apoptotic cell populations, and increased mitochondrial membrane potential in a dose-dependent manner. Furthermore, Resveratrol increased MDM2 expression, inhibiting P53 and downstream pro-apoptotic signaling. Nutlin-3a, an MDM2 inhibitor, reversed the anti-apoptotic effects of Resveratrol. Overexpression of MDM2 in the colon protected against DSS-induced damage.

Conclusion

Resveratrol is an effective treatment for DSS-induced UC, primarily by inhibiting excessive apoptosis in colonocytes through the MDM2/P53/PUMA axis. MDM2 presents a promising therapeutic target for UC treatment.

Regulation and therapeutic potential of NLRP3 inflammasome in intestinal diseases

The NOD-like receptor family, particularly the protein 3 that contains the pyrin domain (NLRP3), is an intracellular sensing protein complex responsible for detecting patterns associated with pathogens and injuries. NLRP3 plays a crucial role in the innate immune response. Currently, a wide range of research has indicated the crucial importance of NLRP3 in various inflammatory conditions. Similarly, the NLRP3 inflammasome plays a significant role in preserving intestinal balance and impacting the advancement of diseases. In addition, several randomized trials have demonstrated the safety and efficacy of targeting NLRP3 in the treatment of colitis, colorectal cancer, and related diseases. This review explores the mechanisms of NLRP3 assembly and activation in the gut. We describe its pathological significance in intestinal diseases. Finally, we summarize current and future therapeutic approaches targeting NLRP3 for intestinal diseases.

Autosomal Dominant Polycystic Kidney Disease-Related Multifocal Renal Cell Carcinoma: A Narrative Iconographic Review

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common inheritable disease of cystic degeneration in the kidney. ADPKD is a significant cause of end-stage renal disease (ESRD). Autosomal Dominant Polycystic Liver Disease (ADPLD) results in substantial PLD with minimal PKD. Currently, there are eight genes which have been associated with ADPKD (PKD1 and PKD2), ADPLD (PRKCSH, SEC63, LRP5, ALG8, and SEC61B), or both (GANAB). The severity of ADPKD can show an extremely broad range, but the evolution to ESRD is doubtless unavoidable. In some patients, carcinogenesis develops with inflammation as a potential promoting factor. In this chapter, we illustrate the severity of ADPKD and the fate to develop renal cell carcinoma (RCC).

The low-dose CHK1 inhibitor prexasertib triggers VDAC1 dephosphorylation to activate mtDNA-STING signaling and synergize immunotherapy

CHK1 inhibitors exhibit dose-limiting toxicity despite potent tumor cytotoxicity in clinical trials. Here, we reveal that low-dose prexasertib induces mtDNA damage by impairing repair machinery, triggering cytosolic mtDNA release via VDAC1 to activate STING-mediated innate immunity. Mechanistically, prexasertib blocks CHK1 phosphorylation and competitively recruits Nek1 kinase, thereby activating the ATR/CHK1 signaling cascade. Consequently, it disrupts the phosphorylation of VDAC1 by Nek1 kinase at T107 and promotes the formation of VDAC1 oligomers, where mtDNA exits. In vivo, low-dose prexasertib exhibits immune-modulatory effects and synergizes safely with immune checkpoint blockade at subtherapeutic doses. Our findings establish reduced-dose CHK1 inhibition as a strategy to amplify immunotherapy efficacy while circumventing systemic toxicity, providing a translatable framework for optimizing therapeutic windows in clinical oncology.

Self-disassembling nanoparticles as oral nanotherapeutics targeting intestinal microenvironment

Inspired by the survival strategies of pyomelanin-producing microbes, we synthesize pyomelanin nanoparticles (PMNPs) from homogentisic acid- γ-lactone via auto-oxidation and investigate their biomedical potential. PMNPs possess distinct physicochemical properties, including reactive oxygen species scavenging and microenvironment-responsive self-disassembly. Under intestinal conditions, PMNPs self-disassemble and penetrate the nanoscale pores of the mucin layer. In an inflammatory bowel disease model, orally administered PMNPs withstand gastric acidity and, in their solubilized form, interact with macrophages and epithelial cells. They significantly reduce reactive oxygen species levels, exert anti-inflammatory effects, and restore gut microbiota composition. Compared to conventional nanoparticles and 5-aminosalicylic acid, PMNPs exhibit greater therapeutic efficacy. Clinical symptoms and intestinal inflammation are alleviated, and the gut microbiota is restored to near-normal levels. These findings underscore the therapeutic potential of PMNPs for inflammatory bowel disease treatment and suggest broader biomedical applications.

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

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

Mitochondrial damage-associated molecular patterns: New perspectives for mitochondria and inflammatory bowel diseases

Mitochondria are key regulators of inflammatory responses and mitochondrial dysfunction is closely linked to various inflammatory diseases. Increasing genetic and experimental evidence suggests that mitochondria play a critical role in inflammatory bowel disease (IBD). In the complex environment of the intestinal tract, intestinal epithelial cells (IECs) and their mitochondria possess unique phenotypic features, shaping each other and regulating intestinal homeostasis and inflammation through diverse mechanisms. Here, we focus on intestinal inflammation in IBD induced by mitochondrial damage-associated molecular patterns (mtDAMPs), which comprise mitochondrial components and metabolic products. The pathogenic mechanisms of mtDAMP signaling pathways mediated by two major mtDAMPs, mitochondrial DNA (mtDNA) and mitochondrial reactive oxygen species (mtROS), are discussed.

VDAC1 Inhibition Protects Against Noise-Induced Hearing Loss via the PINK1/Parkin Pathway

AIMS

This study examined the effect of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), an anion channel blocker of voltage-dependent anion channel 1 (VDAC1), on noise-induced hearing loss (NIHL) and its underlying mechanisms.

METHODS

Cochlear explants and House Ear Institute-Organ of Corti 1 (HEI-OC1) cells were used to assess the effect of DIDS in vitro. Auditory brainstem responses were used to assess auditory functions in mice. Immunofluorescence staining of myosin 7a and CTBP2 were used to examine hair cells and synaptic ribbons. The accumulation of reactive oxygen species (ROS) was measured by 4-HNE staining. The gene expression changes of cochlea were analyzed using RNA sequencing.

RESULTS

DIDS reduced the levels of ROS in cochlear explants and attenuated cell death caused by hydrogen peroxide in both cochlear explants and HEI-OC1 cells. In C57BL/6 mice, DIDS reduced ROS generation and tumor necrosis factor-α induced by noise exposure, thereby protecting outer hair cells and inner hair cell synaptic ribbons from noise-induced damage through a mechanism involving the PINK1/Parkin signaling pathway. The preventive effect of DIDS in cochlear explants was eliminated by mitophagy inhibition.

CONCLUSION

VDAC1 inhibition enhances mitophagy in cochlear hair cells, playing a critical role in defending against oxidative stress and inflammation. Downregulation of VDAC1 may thus be considered a therapeutic strategy for preventing cochlear hair cell damage and reducing NIHL.

VDAC1 Inhibition Mitigates Inflammatory Status and Oxidative Stress in Epileptic Mice Treated with the Ketogenic Diet

Due to the pleiotropic effects of ketogenic diet (KD) on pathophysiology, including inflammation and oxidative stress, medical personnels have been intensively exploring the application of it in the management of epilepsy. Meanwhile, the voltage-dependent anion channel 1 (VDAC1) is believed to be involved in regulating inflammatory and oxidative stress processes. However, the correlation between KD and VDAC1 in epilepsy has not been elucidated. Pilocarpine-induced chronic epilepsy model was utilized to examine the effects of VDAC1 antagonist VBIT-4 treatment on seizure activity, behavioral changes, inflammation, and oxidative stress under control diet (CD) and KD conditions, respectively. Chronic VBIT-4 administration mitigates seizure activity and behavioral abnormalities of epileptic mice under KD rather than CD conditions. Our further findings demonstrated that VBIT-4 treatment attenuates inflammatory response and oxidative stress in the hippocampi and serum samples of epileptic mice under KD rather than CD. Taken together, our data suggest a critical role of VDAC1 in mediating the anti-seizure efficacy of the KD, shedding light on developing novel therapeutic interventions to seizure control.

The P2X7-Mediated Mitochondrial ROS as an Emerging Core Target of Tuftsin Nanoparticles in Severe Acute Pancreatitis Therapy via Regulating Mitophagy

20% acute pancreatitis (AP) develops into severe AP (SAP), a global health crisis, with an increased mortality rate to 30%-50%. Mitochondrial damage and immune disorders are direct factors, which exacerbate the occurrence and progression of AP. So far, mitochondrial and immunity injury in SAP remains largely elusive, with no established treatment options available. Immunomodulation is a promising approach to treat pancreatitis. Herein, we proved that Tuftsin (TN), a vital endogenous immunomodulator, can inhibit SAP, while it is limited by extremely short biological half-life, low bioavailability, and the inconvenience of administration. Nano platform is the positive choice. Interestingly, we found that the activated P2X7 signaling was closely associated with the enhanced pancreatic inflammation via damaging mitochondrial function in SAP. Herein, we engineered a nanoplatform containing a Se-Se bond responsive for ROS to deliver TN, namely, DSPE-Se-Se-MPEG@TN (DSSM@TN), contributing to increases in TN's half-life and bioavailability. We synthesized TN-loaded ROS-responsive DSPE-Se-Se- MPEG@TN liposomes (DSSM@TN NPs) via a one-step emulsification method, which exhibited good biosecurity, high stability, suitable size, favorable ROS responsiveness and biocompatibility, as well as excellent capability for releasing TN during oxidative stress and inflammation environment. Moreover, the Se-Se bond with ROS-responsive ability was first proved to play a vital role for TN-loaded liposomes to enhance its anti-inflammation and antioxidant abilities via targeting damaged mitochondria during SAP progression. Mechanistically, DSSM@TN targeting damaged pancreas simultaneously inhibits mitochondrial dysfunction and inflammation in vivo and vitro via mitochondrial P2X7 signaling-impaired Nrf2/HO-1 signaling-inhibited PINK1/PARKIN pathway. Consequently, such a ROS-responsive immunotherapy nanomedicine targeted mitochondria holds great potential in facilitating substantial clinical progress in SAP treatment.

VDAC1-NF-κB/p65-mediated S100A16 contributes to myocardial ischemia/reperfusion injury by regulating oxidative stress and inflammatory response via calmodulin/CaMKK2/AMPK pathway

Myocardial injury triggers intense inflammatory reactions and oxidative stress responses. S100 calcium-binding protein A16 (S100A16), a multi-functional calcium (Ca2+)-binding protein, participates in inflammatory responses and contributes to ischemia/reperfusion (I/R) injury. Nevertheless, the precise mechanism by which S100A16 operates in myocardial I/R injury remains uncertain. Cardiac I/R injury was produced by ligation/release of the left anterior descending artery, and mouse cardiac cells were subjected to hypoxia/reoxygenation (H/R) to determine the biological effects in vitro. We demonstrated that S100A16 was upregulated in the ischemic hearts and cardiac cells after I/R and H/R injury. Adenovirus-mediated S100A16 inhibition led to a considerable improvement in cardiac function with a reduced infarct size, accompanied by a reduction in cardiomyocyte apoptosis. Similar effects of S100A16 inhibition on inflammation and reactive oxygen species (ROS) production were observed in cultured cardiomyocytes. Importantly, we showed that I/R and H/R treatment upregulated the expression of voltage-dependent anion channel 1 (VDAC1), which subsequently activated NF-κB/p65 to facilitate the binding of NF-κB/p65 to the S100A16 promoter, thereby activating the transcription and expression of S100A16. Mechanically, S100A16 responded to increasing Ca2+ and interacted with calmodulin (CaM) to regulate the activation of calcium/calmodulin-dependent protein kinase 2 (CAMKK2)/AMPK pathway. In conclusion, VDAC1 sustained the NF-κB p65 pathway activation to elicit increased S100A16 expression, contributing to myocardial damage and heart failure post-I/R via the CaM/CaMKK2/AMPK pathway. This study revealed a crucial role of the VDAC1-S100A16 axis in the process of myocardial I/R injury, providing novel molecular targets for the treatment of cardiac conditions associated with I/R injury.

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.

HMGCS2 and AMACR as potential targets linking mitochondrial dysfunction and ulcerative colitis

Ulcerative colitis (UC) is characterised notably by an imbalance in intestinal mucosal homeostasis. Although mitochondrial dysfunction has been identified as a potential contributor to this imbalance, it remains an incomplete understanding. Consequently, further investigation into the role of mitochondria in UC is warranted. The study focusing on the GSE87466 dataset for differential gene expression analysis. Mitochondria-related genes were sourced from the MitoCart3.0 database. Weighted Gene Co-expression Network Analysis (WGCNA) was employed to identify hub genes. The intersection of DEGs, hub genes, and mitochondria-related genes facilitated the identification of 14 mitochondria-related differentially expressed genes (MitoDEGs). Three machine learning algorithms were then applied to select signature MitoDEGs specific to UC: HMGCS2 and AMACR. They have decreased expression in UC patients and have a high diagnostic value for UC. In the inflammatory environment, knockout of both HMGCS2 and AMACR showed disruption of mitochondrial structure and function. Among them, the AMACR knockdown group had an increased number of damaged mitochondria and a significant reduction in the length, area and circumference of MAMs. Therefore, the study identified two new signature MitoDEGs in UC. HMGCS2 and AMACR provide insights into the interplay between mitochondrial dysfunction and UC intestinal mucosal homeostasis.

Sulindac prevents increased mitochondrial VDAC1 expression and cell surface mistargeting induced by pathological conditions in retinal cells

Diabetic retinopathy (DR) continues to be the primary cause of vision loss in poorly controlled diabetic subjects. The molecular mechanisms underlying retinal pigment epithelium (RPE) cell dysfunction in DR still remain elusive. We investigated the role of mitochondrial volt-age-dependent anion channel 1 (VDAC1) in RPE dysfunction under glucotoxic and inflammatory conditions. Our results demonstrate that both glucotoxicity and cytokine treatment reduces cellular viability accompanied by increased VDAC1 and inducible nitric oxide synthase (iNOS) expression, concomitant with decreased expression of mitochondrial VDAC2 and constitutively ex-pressed endothelial NOS (eNOS). Increased VDAC1 expression during these conditions leads to its mistargeting to the cell surface, leading to ATP loss. Additionally, VDAC1 upregulation by glucotoxicity and inflammatory cytokines induces leakage of mitochondrial DNA (mtDNA) into the cytosol. Sulindac, a nonsteroidal anti-inflammatory agent, mitigates the adverse effects associated with increased VDAC1 level under pathophysiological conditions, by suppressing VDAC1 expression. The effect of sulindac on restoring cell viability could be comparably achieved only with VDAC1 inhibitor (VBIT-4) or VDAC1-specific antibody and not with the iNOS inhibitor aminoguanidine. Our findings suggest that sulindac's beneficial effects on ARPE-19 cell function are mediated by prevention of increased VDAC1 expression under pathological conditions, thus preventing mtDNA leakage and ATP loss, which are the key steps in induction of cellular inflammatory responses involved in the development of DR.

Elevated serum mtDNA in COVID-19 patients is linked to SARS-CoV-2 envelope protein targeting mitochondrial VDAC1, inducing apoptosis and mtDNA release

Mitochondria dysfunction is implicated in cell death, inflammation, and autoimmunity. During viral infections, some viruses employ different strategies to disrupt mitochondria-dependent apoptosis, while others, including SARS-CoV-2, induce host cell apoptosis to facilitate replication and immune system modulation. Given mitochondrial DNAs (mtDNA) role as a pro-inflammatory damage-associated molecular pattern in inflammatory diseases, we examined its levels in the serum of COVID-19 patients and found it to be high relative to levels in healthy donors. Furthermore, comparison of serum protein profiles between healthy individuals and SARS-CoV-2-infected patients revealed unique bands in the COVID-19 patients. Using mass spectroscopy, we identified over 15 proteins, whose levels in the serum of COVID-19 patients were 4- to 780-fold higher. As mtDNA release from the mitochondria is mediated by the oligomeric form of the mitochondrial-gatekeeper-the voltage-dependent anion-selective channel 1 (VDAC1)-we investigated whether SARS-CoV-2 protein alters VDAC1 expression. Among the three selected SARS-CoV-2 proteins, small envelope (E), nucleocapsid (N), and accessory 3b proteins, the E-protein induced VDAC1 overexpression, VDAC1 oligomerization, cell death, and mtDNA release. Additionally, this protein led to mitochondrial dysfunction, as evidenced by increased mitochondrial ROS production and cytosolic Ca2+ levels. These findings suggest that SARS-CoV-2 E-protein induces mitochondrial dysfunction, apoptosis, and mtDNA release via VDAC1 modulation. mtDNA that accumulates in the blood activates the cGAS-STING pathway, triggering inflammatory cytokine and chemokine expression that contribute to the cytokine storm and tissue damage seen in cases of severe COVID-19.

HNF-1β alleviates podocyte injury in lupus nephritis by maintaining endoplasmic reticulum homeostasis

OBJECTIVE

The current study aims to elucidate the critical function of hepatocyte nuclear factor 1-beta (HNF1-β) in lupus nephritis (LN) by investigating its modulation of the Derlin-1/valosin-containing protein (VCP)/VCP-interacting membrane selenoprotein (VIMP) complex, endoplasmic reticulum (ER) stress and podocyte apoptosis.

METHODS

In vitro and in vivo models of LN were established using glomerular podocytes treated with LN serum and MRL/lpr mice, respectively. The expression levels of HNF1-β were analysed in kidney tissues from patients with LN and MRL/lpr mice. To assess the effects of HNF1-β inhibition, an adeno-associated virus vector carrying HNF1-β short hairpin was administered to MRL/lpr mice. In vitro, glomerular podocytes were transfected with HNF1-β small interfering RNA (siRNA) or HNF1-β overexpression plasmids to explore their regulatory effects on the Derlin-1/VCP/VIMP complex and podocyte apoptosis. Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays were performed to investigate the transcriptional activation of Derlin-1 and VCP promoters by HNF1-β.

RESULTS

A significant decrease in HNF1-β levels was observed in kidney tissues from patients with LN while MRL/lpr mice exhibited an initial compensatory increase followed by a subsequent decrease in renal HNF1-β expression. Overexpression of HNF1-β transcriptionally upregulated Derlin-1 and VCP mitigating LN serum-induced ER stress and podocyte apoptosis. In contrast, HNF1-β inhibition exacerbated renal dysfunction and structural damage in MRL/lpr mice. Interestingly, HNF1-β inhibition transcriptionally repressed ERP44, leading to calcium ions (Ca²+) release-mediated disruption and inactivation of the Derlin-1/VCP/VIMP complex. This finding suggests that HNF1-β not only regulates the expression of key proteins in the Derlin-1/VCP/VIMP complex but also influences their assembly through Ca²+ release regulation.

CONCLUSION

This study provides novel insights into the regulatory mechanisms of HNF1-β in LN emphasising its impact on the Derlin-1/VCP/VIMP complex, ER stress and podocyte apoptosis. These findings have the potential to inform the development of new diagnostic tools and therapeutic strategies for LN.

Decoding Cancer through Silencing the Mitochondrial Gatekeeper VDAC1

Mitochondria serve as central hubs for regulating numerous cellular processes that include metabolism, apoptosis, cell cycle progression, proliferation, differentiation, epigenetics, immune signaling, and aging. The voltage-dependent anion channel 1 (VDAC1) functions as a crucial mitochondrial gatekeeper, controlling the flow of ions, such as Ca2+, nucleotides, and metabolites across the outer mitochondrial membrane, and is also integral to mitochondria-mediated apoptosis. VDAC1 functions in regulating ATP production, Ca2+ homeostasis, and apoptosis, which are essential for maintaining mitochondrial function and overall cellular health. Most cancer cells undergo metabolic reprogramming, often referred to as the "Warburg effect", supplying tumors with energy and precursors for the biosynthesis of nucleic acids, phospholipids, fatty acids, cholesterol, and porphyrins. Given its multifunctional nature and overexpression in many cancers, VDAC1 presents an attractive target for therapeutic intervention. Our research has demonstrated that silencing VDAC1 expression using specific siRNA in various tumor types leads to a metabolic rewiring of the malignant cancer phenotype. This results in a reversal of oncogenic properties that include reduced tumor growth, invasiveness, stemness, epithelial-mesenchymal transition. Additionally, VDAC1 depletion alters the tumor microenvironment by reducing angiogenesis and modifying the expression of extracellular matrix- and structure-related genes, such as collagens and glycoproteins. Furthermore, VDAC1 depletion affects several epigenetic-related enzymes and substrates, including the acetylation-related enzymes SIRT1, SIRT6, and HDAC2, which in turn modify the acetylation and methylation profiles of histone 3 and histone 4. These epigenetic changes can explain the altered expression levels of approximately 4000 genes that are associated with reversing cancer cells oncogenic properties. Given VDAC1's critical role in regulating metabolic and energy processes, targeting it offers a promising strategy for anti-cancer therapy. We also highlight the role of VDAC1 expression in various disease pathologies, including cardiovascular, neurodegenerative, and viral and bacterial infections, as explored through siRNA targeting VDAC1. Thus, this review underscores the potential of targeting VDAC1 as a strategy for addressing high-energy-demand cancers. By thoroughly understanding VDAC1's diverse roles in metabolism, energy regulation, mitochondrial functions, and other cellular processes, silencing VDAC1 emerges as a novel and strategic approach to combat cancer.

Effect of mitochondrial translocator protein TSPO on LPS-induced cardiac dysfunction

INTRODUCTION

Sepsis-induced cardiac dysfunction is one of the most serious complications of sepsis. The mitochondrial translocator protein (TSPO), a mitochondrial outer membrane protein, is widely used as a diagnostic marker of inflammation-related diseases and can also lead to the release of inflammatory components. However, whether TSPO has a therapeutic effect on sepsis-induced cardiac dysfunction is unclear.

OBJECTIVES

The aim of this study is to investigate the involvement of TSPO in the pathogenesis of sepsis-induced cardiac dysfunction and elucidate its underlying mechanism, as well as develop therapeutic strategies targeting TSPO for the prevention and treatment of sepsis-induced cardiac dysfunction.

METHODS

The sepsis-induced cardiac dysfunction model was established by intraperitoneal injection of lipopolysaccharide (LPS) in C57BL/6 mice (LPS-induced cardiac dysfunction, LICD). TSPO knockout mice were constructed,and the effects of TSPO was detected by survival rate, echocardiography, HE staining, mitochondrial electron microscopy, TUNEL staining. TSPO-binding proteins were identified by co-immunoprecipitation and mass spectrometry. The mechanisms underlying between TSPO and voltage-dependent anion channel (VDAC) was studied through western blot and immunofluorescence. Proteolysis-Targeting Chimeras (PROTAC) technology was used to construct TSPO-PROTAC molecules that can degrade TSPO.

RESULTS

Our present study found that LPS increased cardiac TSPO expression. Knockout of TSPO in C57BL/6 mice with LICD attenuated the cardiac pathology, mitochondrial dysfunction, and apoptosis of cardiomyocytes and significantly improved cardiac function and survival rate. Co-immunoprecipitation and mass spectrometry identified VDAC as a TSPO binding protein.Down-regulation of TSPO reduced PKA-mediated VDAC phosphorylation and VDAC oligomerization, ameliorated mitochondrial function, and reduced cardiomyocyte apoptosis. The study has clinical translational potential, because administration of TSPO-PROTAC to degrade TSPO improved cardiac function in mice with LICD.

CONCLUSION

This study elucidated the effect of TSPO in LICD, providing a new therapeutic strategy to down-regulate TSPO by administration of TSPO-PROTAC for the prevention and treatment of LICD.

Mitochondrial DNA Programs Lactylation of cGAS to Induce IFN Responses in Patients with Systemic Lupus Erythematosus

Mitochondrial DNA (mtDNA) is frequently released from mitochondria, activating cGAS-STING signaling and inducing type I IFNs (IFN-Is) in systemic lupus erythematosus (SLE). Meanwhile, whether and how the glycolytic pathway was involved in such IFN-I responses in human SLE remain unclear. In this study, we found that monocytes from SLE patients exerted robust IFN-I generation and elevated level of cytosolic mtDNA. Transfection of mtDNA into THP-1 macrophages was efficient in inducing IFN-I responses, together with the strong glycolytic pathway that promoted lactate production, mimicking the SLE phenotype. Blockade of lactate generation abrogated such IFN-I responses and, vice versa, exogenous lactate enhanced the IFN-I generation. Mechanistically, lactate promoted the lactylation of cGAS, which inhibited its binding to E3 ubiquitination ligase MARCHF5, blocking cGAS degradation and leading to strong IFN-I responses. In accordance, targeting lactate generation alleviated disease development in humanized SLE chimeras. Collectively, cytosolic mtDNA drives metabolic adaption toward the glycolytic pathway, promoting lactylation of cGAS for licensing IFN-I responses in human SLE and thereby assigning the glycolytic pathway as a promising therapeutic target for SLE.

Mitochondrial function and gastrointestinal diseases

Mitochondria are dynamic organelles that function in cellular energy metabolism, intracellular and extracellular signalling, cellular fate and stress responses. Mitochondria of the intestinal epithelium, the cellular interface between self and enteric microbiota, have emerged as crucial in intestinal health. Mitochondrial dysfunction occurs in gastrointestinal diseases, including inflammatory bowel diseases and colorectal cancer. In this Review, we provide an overview of the current understanding of intestinal epithelial cell mitochondrial metabolism, function and signalling to affect tissue homeostasis, including gut microbiota composition. We also discuss mitochondrial-targeted therapeutics for inflammatory bowel diseases and colorectal cancer and the evolving concept of mitochondrial impairment as a consequence versus initiator of the disease.

The VDAC1 oligomerization regulated by ATP5B leads to the NLRP3 inflammasome activation in the liver cells under PFOS exposure

As a persistent organic pollutant, perfluorooctane sulfonate (PFOS) has a serious detrimental impact on human health. It has been suggested that PFOS is associated with liver inflammation. However, the underlying mechanisms are still unclear. Here, PFOS was found to elevate the oligomerization tendency of voltage-dependent anion channel 1 (VDAC1) in the mice liver and human normal liver cells L-02. Inhibition of VDAC1 oligomerization alleviated PFOS-induced nucleotide-binding domain and leucine-rich repeat protein-3 (NLRP3) inflammasome activation. Cytoplasmic membrane VDAC1 translocated to mitochondria was also observed in response to PFOS. Therefore, the oligomerization of VDAC1 occurred mainly in the mitochondria. VDAC1 was found to interact with the ATP synthase beta subunit (ATP5B) under PFOS treatment. Knockdown of ATP5B or immobilization of ATP5B to the cytoplasmic membrane alleviated the increased VDAC1 oligomerization and NLRP3 inflammasome activation. Therefore, our results suggested that PFOS induced NLRP3 inflammasome activation through VDAC1 oligomerization, a process dependent on ATP5B to transfer VDAC1 from the plasma membrane to the mitochondria. The findings offer novel perspectives on the activation of the NLRP3 inflammasome, the regulatory mode on VDAC1 oligomerization, and the mechanism of PFOS toxicity.

Unraveling Crucial Mitochondria-Related Genes in the Transition from Ulcerative Colitis to Colorectal Cancer

Purpose

To clarify the significance of mitochondria-related differentially expressed genes (MTDEGs) in UC carcinogenesis through a bioinformatics analysis and provide potential therapeutic targets for patients with UC associated colorectal cancer.

Methods

Microarray GSE37283 was utilized to investigate differentially expressed genes (DEGs) in UC and UC with neoplasia (UCN). MTDEGs were identified by intersecting DEGs with human mitochondrial genes. Utilizing LASSO and random forest analyses, we identified three crucial genes. Subsequently, using ROC curve to investigate the predictive ability of three key genes. Following, three key genes were confirmed in AOM/DSS mice model by Real-time PCR. Finally, single-sample gene set enrichment analysis (ssGSEA) was employed to explore the correlation between the hub genes and immune cells infiltration in UC carcinogenesis.

Results

The three identified hub MTDEGs (HMGCS2, MAVS, RDH13) may exhibit significant diagnostic specificity in the transition from UC to UCN. Real-time PCR assay further confirmed that the expressions of HMGCS2 and RDH13 were significantly downregulated in UCN mice than that in UC mice. ssGSEA analysis revealed the hub genes were highly associated with CD56dim natural killer cells.

Conclusion

RDH13, HMGCS2, and MAVS may become diagnostic indicators and potential biomarkers for UCN. Our research has the potential to enhance our understanding of the mechanisms underlying carcinogenesis in UC.

Inhibition of PKC-δ retards kidney fibrosis via inhibiting cGAS-STING signaling pathway in mice

Kidney fibrosis is considered to be the ultimate aggregation pathway of chronic kidney disease (CKD), but its underlying mechanism remains elusive. Protein kinase C-delta (PKC-δ) plays critical roles in the control of growth, differentiation, and apoptosis. In this study, we found that PKC-δ was highly upregulated in human biopsy samples and mouse kidneys with fibrosis. Rottlerin, a PKC-δ inhibitor, alleviated unilateral ureteral ligation (UUO)-induced kidney fibrosis, inflammation, VDAC1 expression, and cGAS-STING signaling pathway activation. Adeno-associated virus 9 (AAV9)-mediated VDAC1 silencing or VBIT-12, a VDAC1 inhibitor, attenuated renal injury, inflammation, and activation of cGAS-STING signaling pathway in UUO mouse model. Genetic and pharmacologic inhibition of STING relieved renal fibrosis and inflammation in UUO mice. In vitro, hypoxia resulted in PKC-δ phosphorylation, VDAC1 oligomerization, and activation of cGAS-STING signaling pathway in HK-2 cells. Inhibition of PKC-δ, VDAC1 or STING alleviated hypoxia-induced fibrotic and inflammatory responses in HK-2 cells, respectively. Mechanistically, PKC-δ activation induced mitochondrial membrane VDAC1 oligomerization via direct binding VDAC1, followed by the mitochondrial DNA (mtDNA) release into the cytoplasm, and subsequent activated cGAS-STING signaling pathway, which contributed to the inflammation leading to fibrosis. In conclusion, this study has indicated for the first time that PKC-δ is an important regulator in kidney fibrosis by promoting cGAS-STING signaling pathway which mediated by VDAC1. PKC-δ may be useful for treating renal fibrosis and subsequent CKD.

VDAC in Retinal Health and Disease

The retina, a tissue of the central nervous system, is vital for vision as its photoreceptors capture light and transform it into electrical signals, which are further processed before they are sent to the brain to be interpreted as images. The retina is unique in that it is continuously exposed to light and has the highest metabolic rate and demand for energy amongst all the tissues in the body. Consequently, the retina is very susceptible to oxidative stress. VDAC, a pore in the outer membrane of mitochondria, shuttles metabolites between mitochondria and the cytosol and normally protects cells from oxidative damage, but when a cell's integrity is greatly compromised it initiates cell death. There are three isoforms of VDAC, and existing evidence indicates that all three are expressed in the retina. However, their precise localization and function in each cell type is unknown. It appears that most retinal cells express substantial amounts of VDAC2 and VDAC3, presumably to protect them from oxidative stress. Photoreceptors express VDAC2, HK2, and PKM2-key proteins in the Warburg pathway that also protect these cells. Consistent with its role in initiating cell death, VDAC is overexpressed in the retinal degenerative diseases retinitis pigmentosa, age related macular degeneration (AMD), and glaucoma. Treatment with antioxidants or inhibiting VDAC oligomerization reduced its expression and improved cell survival. Thus, VDAC may be a promising therapeutic candidate for the treatment of these diseases.

Interleukin-6 classic and trans-signaling utilize glucose metabolism reprogramming to achieve anti- or pro-inflammatory effects

Interleukin (IL)-6 has anti- and pro-inflammatory functions, controlled by IL-6 classic and trans-signaling, respectively. Differences in the downstream signaling mechanism between IL-6 classic and trans-signaling have not been identified. Here, we report that IL-6 activates glycolysis to regulate the inflammatory response. IL-6 regulates glucose metabolism by forming a complex containing signal-transducing activators of transcription 3 (STAT3), hexokinase 2 (HK2), and voltage-dependent anion channel 1 (VDAC1). The IL-6 classic signaling directs glucose flux to oxidative phosphorylation (OxPhos), while IL-6 trans-signaling directs glucose flux to anaerobic glycolysis. Classic IL-6 signaling promotes STAT3 translocation into mitochondria to interact with pyruvate dehydrogenase kinase-1 (PDK1), leading to pyruvate dehydrogenase α (PDHA) dissociation from PDK1. As a result, PDHA is dephosphorylated, and STAT3 is phosphorylated at Ser727. By contrast, IL-6 trans-signaling promotes the interaction of sirtuin 2 (SIRT2) and lactate dehydrogenase A (LDHA), leading to the dissociation of STAT3 from SIRT2. As a result, LDHA is deacetylated, and STAT3 is acetylated and phosphorylated at Tyr705. IL-6 classic signaling promotes the differentiation of regulatory T cells via the PDK1/STAT3/PDHA axis, whereas IL-6 trans-signaling promotes the differentiation of Th17 cells via the SIRT2/STAT3/LDHA axis. Conclusion: IL-6 classic signaling generates anti-inflammatory functions by shifting energy metabolism to OxPhos, while IL-6 trans-signaling generates pro-inflammatory functions by shifting energy metabolism to anaerobic glycolysis.

Effect of VBIT-4 on the functional activity of isolated mitochondria and cell viability

VBIT-4 is a new inhibitor of the oligomerization of VDAC proteins of the outer mitochondrial membrane preventing the development of oxidative stress, mitochondrial dysfunction, and cell death in various pathologies. However, as a VDAC inhibitor, VBIT-4 may itself cause mitochondrial dysfunction in healthy cells. The article examines the effect of VBIT-4 on the functional activity of rat liver mitochondria and cell cultures. We have demonstrated that high concentrations of VBIT-4 (15-30 μM) suppressed mitochondrial respiration in state 3 and 3UDNP driven by substrates of complex I and II. VBIT-4 induced depolarization of organelles fueled by substrates of complex I but not complex II of the respiratory chain. VBIT-4 has been found to inhibit the activity of complexes I, III, and IV of the respiratory chain. Molecular docking demonstrated that VBIT-4 interacts with the rotenone-binding site in complex I with similar affinity. 15-30 μM VBIT-4 caused an increase in H2O2 production in mitochondria, decreased the Ca2+ retention capacity, but increased the time of Ca2+-dependent mitochondrial swelling. We have found that the incubation of breast adenocarcinoma (MCF-7) with 30 μM VBIT-4 for 48 h led to the decrease of the mitochondrial membrane potential, an increase in ROS production and death of MCF-7 cells. The mechanism of action of VBIT-4 on mitochondria and cells is discussed.

Alisol B regulates AMPK/mTOR/SREBPs via directly targeting VDAC1 to alleviate hyperlipidemia

BACKGROUND

The occurrence of hyperlipidemia is significantly influenced by lipid synthesis, which is regulated by sterol regulatory element binding proteins (SREBPs), thus the development of drugs that inhibit lipid synthesis has become a popular treatment strategy for hyperlipidemia. Alisol B (ALB), a triterpenoid compound extracted from Alisma, has been reported to ameliorate no-nalcoholic steatohepatitis (NASH) and slow obesity. However, the effect of ALB on hyperlipidemia and mechanism are unclear.

PURPOSE

To examine the therapeutic impact of ALB on hyperlipidemia whether it inhibits SREBPs to reduce lipid synthesis.

STUDY DESIGN

HepG2, HL7702 cells, and C57BL/6J mice were used to explore the effect of ALB on hyperlipidemia and the molecular mechanism in vivo and in vitro.

METHODS

Hyperlipidemia models were established using western diet (WD)-fed mice in vivo and oleic acid (OA)-induced hepatocytes in vitro. Western blot, real-time PCR and other biological methods verified that ALB regulated AMPK/mTOR/SREBPs to inhibit lipid synthesis. Cellular thermal shift assay (CETSA), molecular dynamics (MD), and ultrafiltration-LC/MS analysis were used to evaluate the binding of ALB to voltage-dependent anion channel protein-1 (VDAC1).

RESULTS

ALB decreased TC, TG, LDL-c, and increased HDL-c in blood, thereby ameliorating liver damage. Gene set enrichment analysis (GSEA) indicated that ALB inhibited the biosynthesis of cholesterol and fatty acids. Consistently, ALB inhibited the protein expression of n-SREBPs and downstream genes. Mechanistically, the impact of ALB on SREBPs was dependent on the regulation of AMPK/mTOR, thereby impeding the transportation of SREBPs from endoplasmic reticulum (ER) to golgi apparatus (GA). Further investigations indicated that the activation of AMPK by ALB was independent on classical upstream CAMKK2 and LKB1. Instead, ALB resulted in a decrease in ATP levels and an increase in the ratios of ADP/ATP and AMP/ATP. CETSA, MD, and ultrafiltration-LC/MS analysis indicated that ALB interacted with VDAC1. Molecular docking revealed that ALB directly bound to VDAC1 by forming hydrogen bonds at the amino acid sites S196 and H184 in the ATP-binding region. Importantly, the thermal stabilization of ALB on VDAC1 was compromised when VDAC1 was mutated at S196 and H184, suggesting that these amino acids played a crucial role in the interaction.

CONCLUSION

Our findings reveal that VDAC1 serves as the target of ALB, leading to the inhibition of lipid synthesis, presents potential target and candidate drugs for hyperlipidemia.

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 involvement of the mitochondrial membrane in drug delivery

Treatment effectiveness and biosafety are critical for disease therapy. Bio-membrane modification facilitates the homologous targeting of drugs in vivo by exploiting unique antibodies or antigens, thereby enhancing therapeutic efficacy while ensuring biosafety. To further enhance the precision of disease treatment, future research should shift focus from targeted cellular delivery to targeted subcellular delivery. As the cellular powerhouses, mitochondria play an indispensable role in cell growth and regulation and are closely involved in many diseases (e.g., cancer, cardiovascular, and neurodegenerative diseases). The double-layer membrane wrapped on the surface of mitochondria not only maintains the stability of their internal environment but also plays a crucial role in fundamental biological processes, such as energy generation, metabolite transport, and information communication. A growing body of evidence suggests that various diseases are tightly related to mitochondrial imbalance. Moreover, mitochondria-targeted strategies hold great potential to decrease therapeutic threshold dosage, minimize side effects, and promote the development of precision medicine. Herein, we introduce the structure and function of mitochondrial membranes, summarize and discuss the important role of mitochondrial membrane-targeting materials in disease diagnosis/treatment, and expound the advantages of mitochondrial membrane-assisted drug delivery for disease diagnosis, treatment, and biosafety. This review helps readers understand mitochondria-targeted therapies and promotes the application of mitochondrial membranes in drug delivery. STATEMENT OF SIGNIFICANCE: Bio-membrane modification facilitates the homologous targeting of drugs in vivo by exploiting unique antibodies or antigens, thereby enhancing therapeutic efficacy while ensuring biosafety. Compared to cell-targeted treatment, targeting of mitochondria for drug delivery offers higher efficiency and improved biosafety and will promote the development of precision medicine. As a natural material, the mitochondrial membrane exhibits excellent biocompatibility and can serve as a carrier for mitochondria-targeted delivery. This review provides an overview of the structure and function of mitochondrial membranes and explores the potential benefits of utilizing mitochondrial membrane-assisted drug delivery for disease treatment and biosafety. The aim of this review is to enhance readers' comprehension of mitochondrial targeted therapy and to advance the utilization of mitochondrial membrane in drug delivery.

Mitochondrial-related genes PDK2, CHDH, and ALDH5A1 served as a diagnostic signature and correlated with immune cell infiltration in ulcerative colitis

We conducted an investigation to determine the potential of mitochondrial-related genes as diagnostic biomarkers in ulcerative colitis (UC), while also examining their association with immune cell infiltration. To achieve this, we acquired four datasets pertaining to UC, which included gene expression arrays and clinical data, from the GEO database. Subsequently, we selected three signature genes (PDK2, CHDH, and ALDH5A1) to construct a diagnostic model for UC. The nomogram and ROC curves exhibited exceptional diagnostic efficacy. Following this, quantitative real-time polymerase chain reaction and western blotting assays validated the decreased mRNA and protein expression of PDK2, CHDH, and ALDH5A1 in the model of UC cells and dextran sulfate sodium salt (DSS)-induced mice colitis tissues, aligning with the findings in the risk model. This investigation suggested a negative correlation between the expression of ALDH5A1, CHDH, and PDK2 and the infiltration of M1 macrophages. Then, immunofluorescence analysis confirmed the augmented expression of CD86 in the tissue of mice subjected to DSS, while a diminished expression of ALDH5A1, CHDH, and PDK2 was observed. Consequently, it can be inferred that targeting mitochondria-associated genes, namely PDK2, CHDH, and ALDH5A1, holds potential as a viable strategy for prognostic prediction and the implementation of immune therapy for UC.

Sacral Nerve Stimulation Alleviates Intestinal Inflammation Through Regulating the Autophagy of Macrophages and Activating the Inflammasome Mediated by a Cholinergic Antiinflammatory Pathway in Colitis Rats

BACKGROUND

Inflammatory bowel disease (IBD) is characterized by chronic progressive intestinal inflammation. Sacral nerve stimulation (SNS) ameliorates colon inflammation caused by IBD. The aim of this study was to investigate the antiinflammatory benefits of SNS in colitis rats and explore the roles of the cholinergic antiinflammatory pathway, macrophage autophagy, and nucleotide oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3) inflammatory bodies.

MATERIALS AND METHODS

Rats were divided into four groups: healthy control, dextran sulfate sodium (DSS), DSS + sham-SNS, and DSS + SNS groups. An electrode was surgically placed in the right sacral nerve (S3) for stimulation. The disease activity index (DAI) score was recorded each day, and the degree of inflammatory injury was evaluated using hematoxylin and eosin staining. The alpha7 nicotinic acetylcholine receptor (α7nAChR) and autophagy- and NLRP3-related factors were assessed using immunofluorescence staining and Western blotting.

RESULTS

The DSS group showed a higher DAI score, colon shortening, upregulated proinflammatory action, and colon damage, and the DSS + SNS group showed significantly improved symptoms. The number of α7nAChR+ cells and the expression level of autophagy decreased in the DSS group but increased in the DSS + SNS group. Conversely, the DSS group showed increased activation of NLRP3 inflammatory bodies, whereas the DSS + SNS group showed decreased activation of NLRP3 inflammatory bodies.

CONCLUSION

In this study, SNS ameliorated colon inflammation by enhancing macrophage autophagy and inhibiting the activation of NLRP3 inflammatory bodies, which may be related to the opening of the cholinergic antiinflammatory pathway.

The inhibition of VDAC1 oligomerization promotes pigmentation through the CaMK-CRTCs/CREB-MITF pathway

The voltage-dependent anion channel 1 (VDAC1) forms an oligomeric structure on the mitochondrial outer membrane, which plays critical roles in many physiological processes. Research studies have demonstrated that the knockout of VDAC1 increases pigment content and up-regulates the expression of melanogenic genes. Due to its involvement in various physiological processes, the depletion of VDAC1 has significant detrimental effects on cellular functions and the inhibition of VDAC1 oligomerization has recently emerged as a promising strategy for the treatment of several diseases. In this study, we found that VDAC1 oligomerization inhibitors, VBIT-12 and NSC-15364, promote melanogenesis, dendrite formation and melanosome transport in human epidermal melanocytes (HEMCs). Mechanistically, treatment of HEMCs with an oligomerization inhibitor increased the level of cytoplasmic calcium ions, which activated calcium-calmodulin dependent protein kinase (CaMK) and led to the phosphorylation of CREB and the nuclear translocation of CREB-regulated transcription coactivators (CRTCs). Subsequently, CRTCs, p-CREB and CREB-binding protein (CBP) in the nucleus cooperatively recruit the transcription machinery to initiate the transcription of MITF thus promoting pigmentation. Importantly, our study also demonstrates that VDAC1 oligomerization inhibitors increase pigmentation in zebrafish and in human skin explants, highlighting their potential as a therapeutic strategy for skin pigmentation disorders.

VDAC1, as a downstream molecule of MLKL, participates in OGD/R-induced necroptosis by inducing mitochondrial damage

Ischemia-reperfusion (I/R) injury constitutes a significant risk factor for a range of diseases, including ischemic stroke, myocardial infarction, and trauma. Following the restoration of blood flow post-tissue ischemia, oxidative stress can lead to various forms of cell death, including necrosis, apoptosis, autophagy, and necroptosis. Recent evidence has highlighted the crucial role of mitochondrial dysfunction in I/R injury. Nevertheless, there remains much to be explored regarding the molecular signaling network governing cell death under conditions of oxidative stress. Voltage-dependent anion channel 1 (VDAC1), a major component in the outer mitochondrial membrane, is closely involved in the regulation of cell death. In a cellular model of oxygen-glucose deprivation and reoxygenation (OGD/R), which effectively simulates I/R injury in vitro, our study reveals that OGD/R induces VDAC1 oligomerization, consequently exacerbating cell death. Furthermore, we have revealed the translocation of mixed lineage kinase domain-like protein (MLKL) to the mitochondria, where it interacts with VDAC1 following OGD/R injury, leading to an increased mitochondrial membrane permeability. Notably, the inhibition of MLKL by necrosulfonamide hinders the binding of MLKL to VDAC1, primarily by affecting the membrane translocation of MLKL, and reduces OGD/R-induced VDAC1 oligomerization. Collectively, our findings provide preliminary evidence of the functional association between MLKL and VDAC1 in the regulation of necroptosis.

Identification and validation of voltage-dependent anion channel 1-related genes and immune cell infiltration in diabetic nephropathy

AIMS/INTRODUCTION

This study investigated the roles of voltage-dependent anion channel 1-related differentially expressed genes (VRDEGs) in diabetic nephropathy (DN).

MATERIALS AND METHODS

We downloaded two datasets from patients with DN, namely, GSE30122 and GSE30529, from the Gene Expression Omnibus database. VRDEGs associated with DN were obtained from the intersection of voltage-dependent anion channel 1-related genes from the GeneCards database, and differentially expressed genes were screened according to group (DN/healthy) in the two datasets. The enriched pathways of the VRDEGs were analyzed. Hub genes were selected using a protein-protein interaction network, and their predictive value was verified through receiver operating characteristic curve analysis. The CIBERSORTx software examined hub genes and immune cell infiltration associations. The protein expression of hub genes was verified through immunohistochemistry in 16-week-old db/db mice for experimentation as a model of type 2 DN. Finally, potential drugs targeting hub genes that inhibit DN development were identified.

RESULTS

A total of 57 VRDEGs were identified. The two datasets showed high expression of the PI3K, Notch, transforming growth factor-β, interleukin-10 and interleukin-17 pathways in DN. Five hub genes (ITGAM, B2M, LYZ, C3 and CASP1) associated with DN were identified and verified. Immunohistochemistry showed that the five hub genes were highly expressed in db/db mice, compared with db/m mice. The infiltration of immune cells was significantly correlated with the five hub genes.

CONCLUSIONS

Five hub genes were significantly correlated with immune cell infiltration and might be crucial to DN development. This study provides insight into the mechanisms involved in the pathogenesis of DN.

Walnut-Derived Peptide Improves Cognitive Impairment in Colitis Mice Induced by Dextran Sodium Sulfate via the Microbiota-Gut-Brain Axis (MGBA)

In this study, we investigated the protective mechanism of walnut-derived peptide LPLLR (LP-5) against cognitive impairment induced in a dextran sodium sulfate (DSS)-induced colitis mouse model, with emphasis on the microbiota-gut-brain axis (MGBA). The results revealed that LP-5 could improve the learning ability and memory of mice with cognitive impairment and mitigate colitis symptoms, including weight loss, bloody stools, colon shortening, and histopathological changes. Additionally, LP-5 protected the integrity of the intestinal barrier by promoting the expression of tight junction proteins (TJs) while attenuating colonic inflammation by suppressing proinflammatory cytokine and epithelial cell apoptosis. Western blotting indicated that LP-5 treatment suppressed the inflammatory NF-κB/MLCK/MLC signaling pathway activity. Furthermore, LP-5 ameliorated hippocampal neuron damage and protected blood-brain barrier (BBB) integrity by downregulating microglia marker protein Iba-1, increasing TJ protein expression, and restoring the deterioration of synaptic proteins. Importantly, 16S rRNA sequencing results indicated that LP-5 reshaped the abundance of a wide range of gut microbiota at the phylum and genus levels, with increased Prevotella and Akkermansia associated with tryptophan (TRP), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA). These findings suggest that LP-5 could maintain intestinal barrier and BBB integrity, reverse gut dysbiosis, and improve learning and memory ability in colitis mice, providing novel insights into alterations of gut microbes in colitis and a potential new mechanism by which it causes cognitive impairment.

Mitochondrial-regulated Tregs: potential therapeutic targets for autoimmune diseases of the central nervous system

Regulatory T cells (Tregs) can eliminate autoreactive lymphocytes, induce self-tolerance, and suppress the inflammatory response. Mitochondria, as the energy factories of cells, are essential for regulating the survival, differentiation, and function of Tregs. Studies have shown that patients with autoimmune diseases of the central nervous system, such as multiple sclerosis, neuromyelitis optica spectrum disorder, and autoimmune encephalitis, have aberrant Tregs and mitochondrial damage. However, the role of mitochondrial-regulated Tregs in autoimmune diseases of the central nervous system remains inconclusive. Therefore, this study reviews the mitochondrial regulation of Tregs in autoimmune diseases of the central nervous system and investigates the possible mitochondrial therapeutic targets.

Role of Mitochondria in Inflammatory Bowel Diseases: A Systematic Review

Mitochondria are key cellular organelles whose main function is maintaining cell bioenergetics by producing ATP through oxidative phosphorylation. However, mitochondria are involved in a much higher number of cellular processes. Mitochondria are the home of key metabolic pathways like the tricarboxylic acid cycle and β-oxidation of fatty acids, as well as biosynthetic pathways of key products like nucleotides and amino acids, the control of the redox balance of the cell and detoxifying the cell from H2S and NH3. This plethora of critical functions within the cell is the reason mitochondrial function is involved in several complex disorders (apart from pure mitochondrial disorders), among them inflammatory bowel diseases (IBD). IBD are a group of chronic, inflammatory disorders of the gut, mainly composed of ulcerative colitis and Crohn's disease. In this review, we present the current knowledge regarding the impact of mitochondrial dysfunction in the context of IBD. The role of mitochondria in both intestinal mucosa and immune cell populations are discussed, as well as the role of mitochondrial function in mechanisms like mucosal repair, the microbiota- and brain-gut axes and the development of colitis-associated colorectal cancer.

Interaction between mitochondria and microbiota modulating cellular metabolism in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a prototypic complex disease in the gastrointestinal tract that has been increasing in incidence and prevalence in recent decades. Although the precise pathophysiology of IBD remains to be elucidated, a large body of evidence suggests the critical roles of mitochondria and intestinal microbiota in the pathogenesis of IBD. In addition to their contributions to the disease, both mitochondria and gut microbes may interact with each other and modulate disease-causing cell activities. Therefore, we hypothesize that dissecting this unique interaction may help to identify novel pathways involved in IBD, which will further contribute to discovering new therapeutic approaches to the disease. As poorly treated IBD significantly affects the quality of life of patients and is associated with risks and complications, successful treatment is crucial. In this review, we stratify previously reported experimental and clinical observations of the role of mitochondria and intestinal microbiota in IBD. Additionally, we review the intercommunication between mitochondria, and the intestinal microbiome in patients with IBD is reviewed along with the potential mediators for these interactions. We specifically focus on their roles in cellular metabolism in intestinal epithelial cells and immune cells. To this end, we propose a potential therapeutic intervention strategy for IBD.

Combining nano-differential scanning fluorimetry and microscale thermophoresis to investigate VDAC1 interaction with small molecules

The mitochondrial voltage-dependent anion channel 1 (VDAC1) plays a central role in metabolism and apoptosis, which makes it a promising therapeutic target. Nevertheless, molecular mechanisms governing VDAC1 functioning remain unclear. Small-molecule ligands specifically interacting with the channel provide an attractive way of exploring its structure-function relationships and can possibly be used as founding stones for future drug-candidates. While around 30 VDAC1 ligands have been identified over the years, various techniques have been used by research teams, making a fair and direct comparison between compounds impossible. To tackle this issue, we performed ligand-binding assays on a representative set of seventeen known VDAC1 ligands using nano-differential scanning fluorimetry and microscale thermophoresis. While all the compounds have been confirmed as VDAC1 ligands by at least one method, combining both technologies lead to the selection of four molecules (cannabidiol, curcumin, DIDS and VBIT4) as chemical starting points for future design of VDAC1 selective ligands.

Mitochondrial Dysfunction in the Pathogenesis and Treatment of Oral Inflammatory Diseases

Oral inflammatory diseases (OIDs) include many common diseases such as periodontitis and pulpitis. The causes of OIDs consist microorganism, trauma, occlusal factors, autoimmune dis-eases and radiation therapy. When treated unproperly, such diseases not only affect oral health but also pose threat to people's overall health condition. Therefore, identifying OIDs at an early stage and exploring new therapeutic strategies are important tasks for oral-related research. Mitochondria are crucial organelles for many cellular activities and disruptions of mitochondrial function not only affect cellular metabolism but also indirectly influence people's health and life span. Mitochondrial dysfunction has been implicated in many common polygenic diseases, including cardiovascular and neurodegenerative diseases. Recently, increasing evidence suggests that mitochondrial dysfunction plays a critical role in the development and progression of OIDs and its associated systemic diseases. In this review, we elucidated the critical insights into mitochondrial dysfunction and its involvement in the inflammatory responses in OIDs. We also summarized recent research progresses on the treatment of OIDs targeting mitochondrial dysfunction and discussed the underlying mechanisms.

Natural products modulate NLRP3 in ulcerative colitis

Ulcerative colitis (UC) is a clinically common, progressive, devastating, chronic inflammatory disease of the intestine that is recurrent and difficult to treat. Nod-like receptor protein 3 (NLRP3) is a protein complex composed of multiple proteins whose formation activates cysteine aspartate protease-1 (caspase-1) to induce the maturation and secretion of inflammatory mediators such as interleukin (IL)-1β and IL-18, promoting the development of inflammatory responses. Recent studies have shown that NLRP3 is associated with UC susceptibility, and that it maintains a stable intestinal environment by responding to a wide range of pathogenic microorganisms. The mainstay of treatment for UC is to control inflammation and relieve symptoms. Despite a certain curative effect, there are problems such as easy recurrence after drug withdrawal and many side effects associated with long-term medication. NLRP3 serves as a core link in the inflammatory response. If the relationship between NLRP3 and gut microbes and inflammation-associated factors can be analyzed concerning its related inflammatory signaling pathways, its expression status as well as specific mechanism in the course of IBD can be elucidated and further considered for clinical diagnosis and treatment of IBD, it is expected that the development of lead compounds targeting the NLRP3 inflammasome can be developed for the treatment of IBD. Research into the prevention and treatment of UC, which has become a hotbed of research in recent years, has shown that natural products are rich in therapeutic means, and multi-targets, with fewer adverse effects. Natural products have shown promise in treating UC in numerous basic and clinical trials over the past few years. This paper describes the regulatory role of the NLRP3 inflammasome in UC and the mechanism of recent natural products targeting NLRP3 against UC, which provides a reference for the clinical treatment of this disease.

Mitochondrial dysfunctions in T cells: focus on inflammatory bowel disease

Mitochondria has emerged as a critical ruler of metabolic reprogramming in immune responses and inflammation. In the context of colitogenic T cells and IBD, there has been increasing research interest in the metabolic pathways of glycolysis, pyruvate oxidation, and glutaminolysis. These pathways have been shown to play a crucial role in the metabolic reprogramming of colitogenic T cells, leading to increased inflammatory cytokine production and tissue damage. In addition to metabolic reprogramming, mitochondrial dysfunction has also been implicated in the pathogenesis of IBD. Studies have shown that colitogenic T cells exhibit impaired mitochondrial respiration, elevated levels of mROS, alterations in calcium homeostasis, impaired mitochondrial biogenesis, and aberrant mitochondria-associated membrane formation. Here, we discuss our current knowledge of the metabolic reprogramming and mitochondrial dysfunctions in colitogenic T cells, as well as the potential therapeutic applications for treating IBD with evidence from animal experiments.

Overexpression of the mitochondrial anti-viral signaling protein, MAVS, in cancers is associated with cell survival and inflammation

Mitochondrial anti-viral signaling protein (MAVS) plays an important role in host defense against viral infection via coordinating the activation of NF-κB and interferon regulatory factors. The mitochondrial-bound form of MAVS is essential for its anti-viral innate immunity. Recently, tumor cells were proposed to mimic a viral infection by activating RNA-sensing pattern recognition receptors. Here, we demonstrate that MAVS is overexpressed in a panel of viral non-infected cancer cell lines and patient-derived tumors, including lung, liver, bladder, and cervical cancers, and we studied its role in cancer. Silencing MAVS expression reduced cell proliferation and the expression and nuclear translocation of proteins associated with transcriptional regulation, inflammation, and immunity. MAVS depletion reduced expression of the inflammasome components and inhibited its activation/assembly. Moreover, MAVS directly interacts with the mitochondrial protein VDAC1, decreasing its conductance, and we identified the VDAC1 binding site in MAVS. Our findings suggest that MAVS depletion, by reducing cancer cell proliferation and inflammation, represents a new target for cancer therapy.

Novel mRNA Signature for Anti-TNF-α Therapy Primary Response in Patients With Ulcerative Colitis

BACKGROUND

Ulcerative colitis (UC), an idiopathic, chronic inflammatory disorder of the colonic mucosa, is commonly treated with antitumor necrosis factor α (anti-TNF-α) agents. However, only approximately two-thirds have an initial response to these therapies.

METHODS

We integrated gene expression profiling from 3 independent data sets of 79 UC patients before they began anti-TNF-α therapy and calculated the differentially expressed genes between patient response and nonresponse to anti-TNF-α therapy and developed a de novo response-associated transcription signature score (logOR_Score) to demonstrate the predictive capability of anti-TNF-α therapy for therapeutic efficacy. Furthermore, we performed association analysis of the logOR_Score and clinical features, such as disease activity and immune microenvironment.

RESULTS

A total of 2522 responsive and 1824 nonresponsive genes were identified from the integrated data set. Responsive genes were significantly enriched in metabolism-related pathways, whereas nonresponsive ones were associated with immune response-related pathways. The logOR_Score enabled the accurate prediction of the therapeutic efficacy of anti-TNF-α in 4 independent patient cohorts and outperformed the predictions made based on 6 transcriptome-based signatures. In terms of clinical features, the logOR_Score correlated highly with the activity of UC. From an immune microenvironment perspective, logOR_Scores of CD8+IL-17+ T cells, follicular B cells, and innate lymphoid cells significantly decreased in inflamed UC tissue.

CONCLUSIONS

The de novo response-associated transcription signature may provide novel insights into the personalized treatment of patients with UC. Comprehensive analyses of the response-related subtypes and the association between logOR_Score and clinical features and immune microenvironment may provide insights into the underlying UC pathogenesis.

[VDAC1 participates in house dust mite-induced asthmatic airway inflammation in mice by inducing ferroptosis of airway epithelial cells]

OBJECTIVE

To investigate the role of voltage-dependent anion-selective channel protein 1 (VDAC1) in house dust mite (HDM)-induced asthmatic airway inflammation and its mechanism for regulating ferroptosis in airway epithelial cells.

METHODS

Human airway epithelial (HBE) cells were exposed to a concentration gradient (200, 400 and 800 U) of HDM alone or in combination with treatment with 10 μmol/L VBIT-4 (a VDAC1 inhibitor) for 24 h, and the expressions of VDAC1 and ferroptosis-associated proteins in the cells were examined. Adult male BALB/c mice were treated with intranasal instillation of VBIT-4, HDM, or both, and the level of airway inflammation and the expressions of ferroptosis-associated proteins were detected with immunohistochemistry.

RESULTS

In HBE cells, HDM exposure caused a significant increase of mitochondrial ROS (mtROS) production and obviously decreased the mitochondrial membrane potential. The exposed cells showed obviously increased protein expressions of VDAC1 (P=0.005) and FTH1 (P=0.030) but decreased protein expression of GPX4 (P=0.015) and FTH1 (P=0.037), while the treatment with VBIT-4 repressed the expression of GPX4 (P=0.001) and inhibited the expression of VDAC1. In BALB/c mice, treatment with VBIT-4 significantly improved HDM-induced airway inflammation by reducing the number of inflammatory cells (P=0.029) in the airway and the number of eosinophils in the alveolar lavage fluid. Immunohistochemical staining showed that GPX4 expression in the airway epithelial cells was significantly increased after treatment with VBIT-4.

CONCLUSIONS

VDAC1 participates in HDM-induced chronic airway inflammation in bronchial asthma by causing ferroptosis of the airway epithelial cells.

Hexokinase dissociation from mitochondria promotes oligomerization of VDAC that facilitates NLRP3 inflammasome assembly and activation

NLRP3 inflammasome activation is a highly regulated process for controlling secretion of the potent inflammatory cytokines IL-1β and IL-18 that are essential during bacterial infection, sterile inflammation, and disease, including colitis, diabetes, Alzheimer's disease, and atherosclerosis. Diverse stimuli activate the NLRP3 inflammasome, and unifying upstream signals has been challenging to identify. Here, we report that a common upstream step in NLRP3 inflammasome activation is the dissociation of the glycolytic enzyme hexokinase 2 from the voltage-dependent anion channel (VDAC) in the outer membrane of mitochondria. Hexokinase 2 dissociation from VDAC triggers activation of inositol triphosphate receptors, leading to release of calcium from the ER, which is taken up by mitochondria. This influx of calcium into mitochondria leads to oligomerization of VDAC, which is known to form a macromolecule-sized pore in the outer membranes of mitochondria that allows proteins and mitochondrial DNA (mtDNA), often associated with apoptosis and inflammation, respectively, to exit the mitochondria. We observe that VDAC oligomers aggregate with NLRP3 during initial assembly of the multiprotein oligomeric NLRP3 inflammasome complex. We also find that mtDNA is necessary for NLRP3 association with VDAC oligomers. These data, together with other recent work, help to paint a more complete picture of the pathway leading to NLRP3 inflammasome activation.

Chitosan functionalized Mn3O4 nanoparticles counteracts ulcerative colitis in mice through modulation of cellular redox state

Recent findings suggest a key role for reactive oxygen species (ROS) in the pathogenesis and progression of ulcerative colitis (UC). Several studies have also highlighted the efficacy of citrate functionalized Mn3O4 nanoparticles as redox medicine against a number of ROS-mediated disorders. Here we show that synthesized nanoparticles consisting of chitosan functionalized tri-manganese tetroxide (Mn3O4) can restore redox balance in a mouse model of UC induced by dextran sulfate sodium (DSS). Our in-vitro characterization of the developed nanoparticle confirms critical electronic transitions in the nanoparticle to be important for the redox buffering activity in the animal model. A careful administration of the developed nanoparticle not only reduces inflammatory markers in the animals, but also reduces the mortality rate from the induced disease. This study provides a proof of concept for the use of nanomaterial with synergistic anti-inflammatory and redox buffering capacity to prevent and treat ulcerative colitis.

DYNLT1 promotes mitochondrial metabolism to fuel breast cancer development by inhibiting ubiquitination degradation of VDAC1

BACKGROUND

Mitochondrial metabolism has been proposed as an attractive target for breast cancer therapy. The discovery of new mechanisms underlying mitochondrial dysfunction will facilitate the development of new metabolic inhibitors to improve the clinical treatment of breast cancer patients. DYNLT1 (Dynein Light Chain Tctex-Type 1) is a key component of the motor complex that transports cellular cargo along microtubules in the cell, but whether and how DYNLT1 affects mitochondrial metabolism and breast cancer has not been reported.

METHODS

The expression levels of DYNLT1 were analyzed in clinical samples and a panel of cell lines. The role of DYNLT1 in breast cancer development was investigated using in vivo mouse models and in vitro cell assays, including CCK-8, plate cloning and transwell assay. The role of DYNLT1 in regulating mitochondrial metabolism in breast cancer development is examined by measuring mitochondrial membrane potential and ATP levels. To investigate the underlying molecular mechanism, many methods, including but not limited to Co-IP and ubiquitination assay were used.

RESULTS

First, we found that DYNLT1 was upregulated in breast tumors, especially in ER + and TNBC subtypes. DYNLT1 promotes the proliferation, migration, invasion and mitochondrial metabolism in breast cancer cells in vitro and breast tumor development in vivo. DYNLT1 colocalizes with voltage-dependent anion channel 1 (VDAC1) on mitochondria to regulate key metabolic and energy functions. Mechanistically, DYNLT1 stabilizes the voltage-dependent anion channel 1 (VDAC1) by hindering E3 ligase Parkin-mediated VDAC1 ubiquitination and degradation.

CONCLUSION

Our data demonstrate that DYNLT1 promotes mitochondrial metabolism to fuel breast cancer development by inhibiting Parkin-mediated ubiquitination degradation of VDAC1. This study suggests that mitochondrial metabolism can be exploited by targeting the DYNLT1-Parkin-VDAC1 axis to improve the ability of metabolic inhibitors to suppress cancers with limited treatment options, such as triple-negative breast cancer (TNBC).