Mitochondrial Fission Mediates Endothelial Inflammation

Hyperbaric oxygen therapy attenuated limb ischemia in mice with high-fat diet by restoring Sirtuin 1 and mitochondrial function

Hyperbaric oxygen therapy (HBO) shows promise as a treatment for peripheral artery disease (PAD), particularly when complicated by metabolic syndrome and diabetes. However, its precise effects on endothelial function remain unclear. This study explored the impact of HBO on angiogenesis and apoptosis in high-fat diet (HFD)-fed mice with limb ischemia, focusing on the role of sirtuin 1 (SIRT1). After 8 weeks on a chow or HFD, mice underwent unilateral femoral artery ligation and received HBO (3 ATA, 1 h/day for 5 days). HBO improved blood flow, enhanced vascular density, and reduced apoptosis in ischemic calf muscles of HFD-fed mice. In vitro, human umbilical vein endothelial cells (HUVECs) were subjected to high-glucose and oxygen-glucose deprivation (OGD) conditions, with or without HBO. HBO restored cell proliferation, migration, and tube formation under these conditions, reduced mitochondrial dysfunction, and decreased reactive oxygen species (ROS) production. However, these benefits were reversed by treatment with sirtinol, a SIRT1 inhibitor. HBO also increased SIRT1 expression and shifted mitochondrial dynamics toward fusion. Additionally, HBO upregulated angiogenesis-related proteins (VEGF, VEGFR, and SIRT1) while downregulating apoptosis-associated proteins (Bax, caspase-3, and p53). Collectively, these findings suggest that HBO enhances angiogenesis and reduces apoptosis in both in vivo and in vitro ischemia models, primarily through SIRT1 activation.

Decoding interaction between mitochondria and endoplasmic reticulum in ischemic myocardial injury: targeting natural medicines

Ischemic cardiomyopathy (ICM) is a special type or end stage of coronary heart disease or other irreversible ischemic myocardial injury. Inflammatory damage to coronary vessels is a crucial factor in causing stenosis or occlusion of coronary arteries, resulting in myocardial ischemia and hypoxia, but it is also an aspect of cardioprotection that is often overlooked. This review discusses the mechanisms of vascular injury during ICM, in which inflammation and oxidative stress interact and trigger cell death as the cause of coronary microvascular injury. Imbalances in endoplasmic reticulum function and mitochondrial quality control are important potential drivers of inflammation and oxidative stress. In addition, many studies have confirmed the therapeutic effects of Chinese herbal medicines and their natural monomeric components on vascular injuries. Their mitochondrial quality control and endoplasmic reticulum protection mechanisms as well as their role in combating improvements in vascular endothelial function and attenuating vascular injury are also summarized, with a perspective to provide a reference for pathologic understanding, drug research, and clinical application of ICM-associated coronary microvascular injury.

Harnessing exercise to combat chronic diseases: the role of Drp1-Mediated mitochondrial fission

Enhanced Drp1 activity mediates excessive mitochondrial fission, contributing to the onset and progression of various chronic diseases, including neurodegenerative, cardiovascular, and metabolic disorders. Studies indicate that exercise mitigates mitochondrial dysfunction by modulating Drp1-related signaling targets, thereby inhibiting Drp1 activity and reducing excessive mitochondrial fission. This, in turn, enhances mitochondrial function and cellular metabolism. This review synthesizes the current understanding of Drp1 structure and activation mechanisms, and analyzes the effects of exercise interventions on Drp1-mediated mitochondrial fission in different disease models to improve common chronic conditions. This research deepens our insight into the specific mechanisms of Drp1-induced excessive mitochondrial fission in chronic disease pathogenesis, offering new theoretical support and practical guidance for exercise as a non-pharmacological intervention strategy.

The dual role of PGAM5 in inflammation

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

Mitochondrial dysfunction in myasthenia gravis: Exploring directions for future immunotherapy? A review

Myasthenia gravis (MG) is an acquired autoimmune disease characterized by impaired transmission at the neuromuscular junction, primarily manifesting as fluctuating muscle weakness, fatigability, and partial paralysis. Due to its long disease course, treatment resistance, and frequent relapses, it places a significant burden on patients and their families. In recent years, advances in molecular biology have provided growing evidence that mitochondrial dysfunction impairs muscle function and affects immune cell proliferation and differentiation in patients. Mitochondria, as the cell's energy source, play a critical role in various pathological processes in MG, including oxidative stress, dynamic abnormalities, mitophagy, and mitochondrial metabolism. The role of mitochondrial dysfunction in the pathogenesis of MG has garnered increasing attention. This manuscript primarily explores mitochondrial function and abnormal morphological changes in MG, as well as mitochondrial quality control, metabolic reprogramming, and their potential mechanisms in the pathological changes of the disease. It also reviews the current status of drug therapies aimed at improving mitochondrial function. The goal is to provide novel perspectives and strategies for future mitochondrial-targeted therapies in MG.

Impaired endothelial function contributes to cardiac dysfunction: role of mitochondrial dynamics

The endothelial microvasculature is essential for the regulation of vasodilation and vasoconstriction, and improved functioning of the endothelium is linked to improved outcomes for individuals with coronary artery disease (CAD). People with endothelial dysfunction exhibit a loss of nitric oxide (NO)-mediated vasodilation, achieving vasodilation instead through mitochondria-derived H2O2. Mitochondrial dynamics is an important autoregulatory mechanism that contributes to mitochondrial and endothelial homeostasis and plays a role in the formation of reactive oxygen species (ROS), including H2O2. Dysregulation of mitochondrial dynamics leads to increased ROS production, decreased ATP production, impaired metabolism, activation of pathological signal transduction, impaired calcium sensing, and inflammation. We hypothesize that dysregulation of endothelial mitochondrial dynamics plays a crucial role in the endothelial microvascular dysfunction seen in individuals with CAD. Therefore, proper regulation of endothelial mitochondrial dynamics may be a suitable treatment for individuals with endothelial microvascular dysfunction, and we furthermore postulate that improving this microvascular dysfunction will directly improve outcomes for those with CAD.

Pathological roles of mitochondrial dysfunction in endothelial cells during the cerebral no-reflow phenomenon: A review

Emergency intravascular interventional therapy is the most effective approach to rapidly restore blood flow and manage occlusion of major blood vessels during the initial phase of acute ischemic stroke. Nevertheless, several patients continue to experience ineffective reperfusion or cerebral no-reflow phenomenon, that is, hypoperfusion of cerebral blood supply after treatment. This is primarily attributed to downstream microcirculation disturbance. As integral components of the cerebral microvascular structure, endothelial cells (ECs) attach importance to regulating microcirculatory blood flow. Unlike neurons and microglia, ECs harbor a relatively low abundance of mitochondria, acting as key sensors of environmental and cellular stress in regulating the viability, structural integrity, and function of ECs rather than generating energy. Mitochondria dysfunction including increased mitochondrial reactive oxygen species levels and disturbed mitochondrial dynamics causes endothelial injury, further causing microcirculation disturbance involved in the cerebral no-reflow phenomenon. Therefore, this review aims to discuss the role of mitochondrial changes in regulating the role of ECs and cerebral microcirculation blood flow during I/R injury. The outcomes of the review will provide promising potential therapeutic targets for future prevention and effective improvement of the cerebral no-reflow phenomenon.

Asiaticoside alleviates lipopolysaccharide-induced acute lung injury by blocking Sema4D/CD72 and inhibiting mitochondrial dysfunction in RAW264.7 cell and mice

Acute lung injury (ALI) is a common disease with complex pathogenesis. However, the treatment is mainly symptomatic with limited clinical options. Asiaticoside (AS), a Chinese herbal extract, has protective effects against LPS-induced ALI in mice and inhibits nitric oxide and prostaglandin E2 synthesis; however, the specific mechanism of AS in the prevention and treatment of LPS-induced ALI needs further study. Sema4D/CD72 pathway, mitochondrial dysfunction, and miRNA-21 are closely associated with inflammation. Therefore, the present study aimed to explore whether AS exerts its therapeutic effect on ALI by influencing Sema4D/CD72 pathway and mitochondrial dysfunction, restoring the balance of inflammatory factors, and influencing miRNA-21 expression. Cell and animal experiments were performed to investigate the effect of AS on ALI. Lipopolysaccharide (LPS) was used to establish the ALI model. CCK8 and flow cytometry were used to detect the cell viability and apoptosis rate. HE staining and wet-to-dry weight ratio (W/D) of lung tissue were determined. The expressions of Sema4D, CD72, NF-κB p65, Bax, Bcl2, and caspase 3 in RAW264.7 cells and lung tissues were detected by western blot, and the levels of IL-10 and IL-1β induced by LPS in supernatant of RAW264.7 cells and BALF were measured by ELISA. And the expression of miRNA-21 in cells and lung tissues was detected by fluorescence quantitative PCR. The result shows that AS treatment suppressed LPS-induced cell damage and lung injury in mice. AS treatment could alleviate the pathological changes such as inflammatory infiltration and histopathological changes in the lungs caused by LPS, and reduce the ratio of W/D. AS significantly alleviated the decrease of mitochondrial membrane potential induced by LPS, inhibited the increase of ROS production, and reduced the expression of mitochondrial fission proteins Drp1 and Fis1. The high-dose AS group significantly downregulated the expression of Sema4D, CD72, phosphorylated NF-κB p65, and apoptosis-related proteins, decreased the pro-inflammatory factor IL-1β, and enhanced the level of anti-inflammatory factor IL-10. In addition, AS promoted miRNA-21 expression. These effects inhibited apoptosis and restored the balance between anti- and pro-inflammatory factors. This represents the inaugural report elucidating the mechanism by which AS inhibits the Sema4D/CD72 signaling pathway. These findings offer novel insights into the potential application of AS in both preventing and treating ALI.

Chronic mitochondrial dynamic-targeted therapy alleviates left ventricular dysfunction by reducing multiple programmed cell death in post-myocardial infarction rats

Mitochondrial dysfunction and the activation of multiple programmed cell death (PCD) have been shown to aggravate the severity and mortality associated with the progression of myocardial infarction (MI). Although pharmacological modulation of mitochondrial dynamics, including treatment with the fusion promoter (M1) and the fission inhibitor (Mdivi-1), exerted cardioprotection against several cardiac complications, their roles in the post-MI model have never been investigated. Using a MI rat model instigated by permanent left-anterior descending (LAD) coronary artery occlusion, post-MI rats were randomly assigned to receive one of 4 treatments (n = 10/group): vehicle (DMSO 3%V/V), enalapril (10 mg/kg), Mdivi-1 (1.2 mg/kg) and M1 (2 mg/kg), while a control group of sham operated rats underwent surgery without LAD occlusion (n = 10). After 32-day treatment, cardiac and mitochondrial function, and histopathological morphology were investigated and molecular analysis was performed. Treatment with enalapril, Mdivi-1, and M1 significantly mitigated cardiac pathological remodeling, reduced myocardial injury, and improved left ventricular (LV) function in post-MI rats. Importantly, all interventions also attenuated mitochondrial dynamic imbalance and mitigated activation of apoptosis, necroptosis, and pyroptosis after MI. This investigation demonstrated for the first time that chronic mitochondrial dynamic-targeted therapy mitigated mitochondrial dysfunction and activation of PCD, leading to improved LV function in post-MI rats.

Integrated metabolomics and transcriptomics analysis reveals the mechanism of Tangbi capsule for diabetic lower extremities arterial disease

Objective

Tangbi capsule (TBC) is a traditional Chinese medicine prescription, which has the potential to improve the vascular insufficiency of lower extremities and limb numbness in diabetes. However, the potential mechanism remains unknown. This study aims to investigate the pharmacological effects and mechanism of TBC on rats with diabetic lower extremities arterial disease (LEAD).

Methods

The mechanism of TBC on diabetic LEAD was investigated through metabolomics and transcriptomics analysis, and the main components of TBC were determined by mass spectrometry. The efficacy and mechanism of TBC on diabetic LEAD rats were investigated through in vitro experiments, histopathology, blood flow monitoring, western blot, and real-time polymerase chain reaction.

Results

Mass spectrometry analysis identified 31 active chemical components in TBC including (2R)-2,3-Dihydroxypropanoic acid, catechin, citric acid, miquelianin, carminic acid, salicylic acid, formononetin, etc. In vitro analysis showed that TBC could reduce endothelial cell apoptosis and promote angiogenesis. Histopathological analysis showed that TBC led to an obvious improvement in diabetic LEAD as it improved fibrous tissue proliferation and reduced arterial wall thickening. In addition, TBC could significantly increase the expression levels of HIF-1α, eNOS, and VEGFA proteins and genes while reducing that of calpain-1 and TGF-β, suggesting that TBC can repair vascular injury. Compared with the model group, there were 47 differentially expressed genes in the whole blood of TBC groups, with 25 genes upregulated and 22 downregulated. Eighty-seven altered metabolites were identified from the serum samples. Combining the changes in differentially expressed genes and metabolites, we found that TBC could regulate arginine biosynthesis, phenylalanine metabolism, pyrimidine metabolism, arachidonic acid metabolism, pyrimidine metabolism, arachidonic acid metabolism, nucleotide metabolism, vitamin B6 metabolism and other metabolic pathways related to angiogenesis, immune-inflammatory response, and cell growth to improve diabetic LEAD.

Conclusion

TBC improved vascular endothelial injury, apoptosis, lipid accumulation, liver and kidney function, and restored blood flow in the lower extremities of diabetic LEAD rats. The mechanism of TBC in the treatment of diabetic LEAD may be related to the modulation of inflammatory immunity, lipid metabolism, and amino acid metabolism. This study presented preliminary evidence to guide the use of TBC as a therapy option for diabetic LEAD.

Drp1: Focus on Diseases Triggered by the Mitochondrial Pathway

Drp1 (Dynamin-Related Protein 1) is a cytoplasmic GTPase protein encoded by the DNM1L gene that influences mitochondrial dynamics by mediating mitochondrial fission processes. Drp1 has been demonstrated to play an important role in a variety of life activities such as cell survival, proliferation, migration, and death. Drp1 has been shown to play different physiological roles under different physiological conditions, such as normal and inflammation. Recently studies have revealed that Drp1 plays a critical role in the occurrence, development, and aggravation of a series of diseases, thereby it serves as a potential therapeutic target for them. In this paper, we review the structure and biological properties of Drp1, summarize the biological processes that occur in the inflammatory response to Drp1, discuss its role in various cancers triggered by the mitochondrial pathway and investigate effective methods for targeting Drp1 in cancer treatment. We also synthesized the phenomena of Drp1 involving in the triggering of other diseases. The results discussed herein contribute to our deeper understanding of mitochondrial kinetic pathway-induced diseases and their therapeutic applications. It is critical for advancing the understanding of the mechanisms of Drp1-induced mitochondrial diseases and preventive therapies.

Inhibition of Drp1-mediated mitochondrial fission improves contrast-induced acute kidney injury by targeting the mROS-TXNIP-NLRP3 inflammasome axis

Acute kidney injury (AKI) is a critical complication known for their extremely high mortality rate and lack of effective clinical therapy. Disorders in mitochondrial dynamics possess a pivotal role in the occurrence and progression of contrast-induced nephropathy (CIN) by activating NLRP3 inflammasome. The activation of dynamin-related protein-1 (Drp1) can trigger mitochondrial dynamic disorders by regulating excessive mitochondrial fission. However, the precise role of Drp1 during CIN has not been clarified. In vivo experiments revealed that inhibiting Drp1 through Mdivi-1 (one selective inhibitor of Drp1) can significantly decrease the expression of p-Drp1 (Ser616), mitochondrial p-Drp1 (Ser616), mitochondrial Bax, mitochondrial reactive oxygen species (mROS), NLRP3, caspase-1, ASC, TNF-α, IL-1β, interleukin (IL)-18, IL-6, creatinine (Cr), malondialdehyde (MDA), blood urea nitrogen (BUN), and KIM-1. Moreover, Mdivi-1 reduced kidney pathological injury and downregulated the interaction between NLRP3 and thioredoxin-interacting protein (TXNIP), which was accompanied by decreased interactions between TRX and TXNIP. This resulted in increasing superoxide dismutase (SOD) and CAT activity, TRX expression, up-regulating mitochondrial membrane potential, and augmenting ATP contents and p-Drp1 (Ser616) levels in the cytoplasm. However, it did not bring impact on the expression of p-Drp1 (Ser637) and TXNIP. Activating Drp-1though Acetaldehyde abrogated the effects of Mdivi-1. In addition, the results of in vitro studies employing siRNA-Drp1 and plasmid-Drp1 intervention in HK-2 cells treated with iohexol were consistent with the in vivo experiments. Our findings revealed inhibiting Drp1 phosphorylation at Ser616 could ameliorate iohexol -induced acute kidney injury though alleviating the activation of the TXNIP-NLRP3 inflammasome pathway.

Mitochondrial Dysfunction: A Roadmap for Understanding and Tackling Cardiovascular Aging

Cardiovascular aging is a progressive remodeling process constituting a variety of cellular and molecular alterations that are closely linked to mitochondrial dysfunction. Therefore, gaining a deeper understanding of the changes in mitochondrial function during cardiovascular aging is crucial for preventing cardiovascular diseases. Cardiac aging is accompanied by fibrosis, cardiomyocyte hypertrophy, metabolic changes, and infiltration of immune cells, collectively contributing to the overall remodeling of the heart. Similarly, during vascular aging, there is a profound remodeling of blood vessel structure. These remodeling present damage to endothelial cells, increased vascular stiffness, impaired formation of new blood vessels (angiogenesis), the development of arteriosclerosis, and chronic vascular inflammation. This review underscores the role of mitochondrial dysfunction in cardiac aging, exploring its impact on fibrosis and myocardial alterations, metabolic remodeling, immune response remodeling, as well as in vascular aging in the heart. Additionally, we emphasize the significance of mitochondria-targeted therapies in preventing cardiovascular diseases in the elderly.

Milestone Papers on Signal Transduction Mechanisms of Hypertension and Its Complications

To celebrate 100 years of American Heart Association-supported cardiovascular disease research, this review article highlights milestone papers that have significantly contributed to the current understanding of the signaling mechanisms driving hypertension and associated cardiovascular disorders. This article also includes a few of the future research directions arising from these critical findings. To accomplish this important mission, 4 principal investigators gathered their efforts to cover distinct yet intricately related areas of signaling mechanisms pertaining to the pathogenesis of hypertension. The renin-angiotensin system, canonical and novel contractile and vasodilatory pathways in the resistance vasculature, vascular smooth muscle regulation by membrane channels, and noncanonical regulation of blood pressure and vascular function will be described and discussed as major subjects.

Effects of mitochondrial dysfunction on cellular function: Role in atherosclerosis

Atherosclerosis, an immunoinflammatory disease of medium and large arteries, is associated with life-threatening clinical events, such as acute coronary syndromes and stroke. Chronic inflammation and impaired lipoprotein metabolism are considered to be among the leading causes of atherosclerosis, while numerous risk factors, including arterial hypertension, diabetes mellitus, obesity, and aging, can contribute to the development of the disease. In recent years, emerging evidence has underlined the key role of mitochondrial dysfunction in the pathogenesis of atherosclerosis. Mitochondrial dysfunction is believed to result in an increase in reactive oxygen species, leading to oxidative stress, chronic inflammation, and intracellular lipid deposition, all of which can contribute to the pathogenesis of atherosclerosis. Critical cells, including endothelial cells, vascular smooth muscle cells, and macrophages, play an important role in atherosclerosis. Mitochondrial function is also involved in maintaining the normal function of these cells. To better understand the relationship between mitochondrial dysfunction and atherosclerosis, this review summarizes the findings of recent studies and discusses the role of mitochondrial dysfunction in the risk factors and critical cells of atherosclerosis. FACTS: OPEN QUESTIONS.

Mitochondrial fission inhibition protects against hypertension induced by angiotensin II

Mitochondrial dysfunction has been implicated in various types of cardiovascular disease including hypertension. Mitochondrial fission fusion balance is critical to mitochondrial quality control, whereas enhanced fission has been reported in several models of cardiovascular disease. However, limited information is available regarding the contribution of mitochondrial fission in hypertension. Here, we have tested the hypothesis that inhibition of mitochondrial fission attenuates the development of hypertension and associated vascular remodeling. In C57BL6 mice infused with angiotensin II for 2 weeks, co-treatment of mitochondrial fission inhibitor, mdivi1, significantly inhibited angiotensin II-induced development of hypertension assessed by radiotelemetry. Histological assessment of hearts and aortas showed that mdivi1 inhibited vessel fibrosis and hypertrophy induced by angiotensin II. This was associated with attenuation of angiotensin II-induced decline in mitochondrial aspect ratio seen in both the endothelial and medial layers of aortas. Mdivi1 also mitigated angiotensin II-induced cardiac hypertrophy assessed by heart weight-to-body weight ratio as well as by echocardiography. In ex vivo experiments, mdivi1 inhibited vasoconstriction and abolished the enhanced vascular reactivity by angiotensin II in small mesenteric arteries. Proteomic analysis on endothelial cell culture media with angiotensin II and/or mdivi1 treatment revealed that mdivi1 inhibited endothelial cell hypersecretory phenotype induced by angiotensin II. In addition, mdivi1 attenuated angiotensin II-induced protein induction of periostin, a myofibroblast marker in cultured vascular fibroblasts. In conclusion, these data suggest that mdivi1 prevented angiotensin II-induced hypertension and cardiovascular remodeling via multicellular mechanisms in the vasculature.

Downregulation of Mitochondrial Fusion Protein Expression Affords Protection from Canonical Necroptosis in H9c2 Cardiomyoblasts

Necroptosis, a form of necrosis, and alterations in mitochondrial dynamics, a coordinated process of mitochondrial fission and fusion, have been implicated in the pathogenesis of cardiovascular diseases. This study aimed to determine the role of mitochondrial morphology in canonical necroptosis induced by a combination of TNFα and zVAD (TNF/zVAD) in H9c2 cells, rat cardiomyoblasts. Time-course analyses of mitochondrial morphology showed that mitochondria were initially shortened after the addition of TNF/zVAD and then their length was restored, and the proportion of cells with elongated mitochondria at 12 h was larger in TNF/zVAD-treated cells than in non-treated cells (16.3 ± 0.9% vs. 8.0 ± 1.2%). The knockdown of dynamin-related protein 1 (Drp1) and fission 1, fission promoters, and treatment with Mdivi-1, a Drp-1 inhibitor, had no effect on TNF/zVAD-induced necroptosis. In contrast, TNF/zVAD-induced necroptosis was attenuated by the knockdown of mitofusin 1/2 (Mfn1/2) and optic atrophy-1 (Opa1), proteins that are indispensable for mitochondrial fusion, and the attenuation of necroptosis was not canceled by treatment with Mdivi-1. The expression of TGFβ-activated kinase (TAK1), a negative regulator of RIP1 activity, was upregulated and the TNF/zVAD-induced RIP1-Ser166 phosphorylation, an index of RIP1 activity, was mitigated by the knockdown of Mfn1/2 or Opa1. Pharmacological TAK1 inhibition attenuated the protection afforded by Mfn1/2 and Opa1 knockdown. In conclusion, the inhibition of mitochondrial fusion increases TAK1 expression, leading to the attenuation of canonical necroptosis through the suppression of RIP1 activity.

Chlorantraniliprole induces mitophagy, ferroptosis, and cytokine homeostasis imbalance in grass carp (Ctenopharyngodon idella) hepatocytes via the mtROS-mitochondrial fission/fusion axis

Chlorantraniliprole (CAP) is a bis-amide pesticide used for pest control mainly in agricultural production activities and rice-fish co-culture systems. CAP residues cause liver damage in non-target organism freshwater fish. However, it is unclear whether CAP-exposure-induced liver injury in fish is associated with mitochondrial dysfunction-mediated mitophagy, ferroptosis, and cytokines. Therefore, we established grass carp hepatocyte models exposed to different concentrations of CAP (20, 40, and 80 μM) in vitro. MitoSOX probe, JC-1 staining, immunofluorescence double staining, Fe2+ staining, lipid peroxidation staining, qRT-PCR, and Western blot were used to verify the physiological regulatory mechanism of CAP induced liver injury. In the present study, the CAP-treated groups exhibited down-regulation of antioxidant-related enzyme activities and accumulation of peroxides. CAP treatment induced an increase in mitochondrial reactive oxygen species (mtROS) levels and altered expression of mitochondrial fission/fusion (Drp1, Fis1, Mfn1, Mfn2, and Opa1) genes in grass carp hepatocytes. In addition, mitophagy (Parkin, Pink1, p62, LC3II/I, and Beclin-1), ferroptosis (GPX4, COX2, ACSL4, FTH, and NCOA4), and cytokine (IFN-γ, IL-18, IL-17, IL-6, IL-10, IL-1β, IL-2, and TNF-α)-related gene expression was significantly altered. Collectively, these findings suggest that CAP exposure drives mitophagy activation, ferroptosis occurrence, and cytokine homeostasis imbalance in grass carp hepatocytes by triggering mitochondrial dysfunction mediated by the mtROS-mitochondrial fission/fusion axis. This study partly explained the physiological regulation mechanism of grass carp hepatocyte injury induced by insecticide CAP from the physiological and biochemical point of view and provided a basis for evaluating the safety of CAP environmental residues to non-target organisms.

Metabolic reprogramming of immune cells by mitochondrial division inhibitor-1 to prevent post-vascular injury neointimal hyperplasia

BACKGROUND AND AIMS

New treatments are needed to prevent neointimal hyperplasia that contributes to post-angioplasty and stent restenosis in patients with coronary artery disease (CAD) and peripheral arterial disease (PAD). We investigated whether modulating mitochondrial function using mitochondrial division inhibitor-1 (Mdivi-1) could reduce post-vascular injury neointimal hyperplasia by metabolic reprogramming of macrophages from a pro-inflammatory to anti-inflammatory phenotype.

METHODS AND RESULTS

In vivo Mdivi-1 treatment of Apoe-/- mice fed a high-fat diet and subjected to carotid-wire injury decreased neointimal hyperplasia by 68%, reduced numbers of plaque vascular smooth muscle cells and pro-inflammatory M1-like macrophages, and decreased plaque inflammation, endothelial activation, and apoptosis, when compared to control. Mdivi-1 treatment of human THP-1 macrophages shifted polarization from a pro-inflammatory M1-like to an anti-inflammatory M2-like phenotype, reduced monocyte chemotaxis and migration to CCL2 and macrophage colony stimulating factor (M-CSF) and decreased secretion of pro-inflammatory mediators. Finally, treatment of pro-inflammatory M1-type-macrophages with Mdivi-1 metabolically reprogrammed them to an anti-inflammatory M2-like phenotype by inhibiting oxidative phosphorylation and attenuating the increase in succinate levels and correcting the decreased levels of arginine and citrulline.

CONCLUSIONS

We report that treatment with Mdivi-1 inhibits post-vascular injury neointimal hyperplasia by metabolic reprogramming macrophages towards an anti-inflammatory phenotype thereby highlighting the therapeutic potential of Mdivi-1 for preventing neointimal hyperplasia and restenosis following angioplasty and stenting in CAD and PAD patients.

Mitochondrial Dysfunction in Endothelial Progenitor Cells: Unraveling Insights from Vascular Endothelial Cells

Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.

Excessive Mitochondrial Fission Suppresses Mucosal Repair by Impairing Butyrate Metabolism in Colonocytes

BACKGROUND

Mucosal healing is one of the principal therapeutic targets for ulcerative colitis (UC). Mitochondria are dynamic organelles that undergo constant fusion and fission; however, the process that is most conducive to mucosal healing remains unclear. This study investigated the role of mitochondrial fission in mucosal healing in UC patients.

METHODS

Quantitative polymerase chain reaction, Western blotting, and immunostaining were used to detect mitochondrial fission in UC patients and a dextran sulfate sodium-induced colitis model. Colonic organoids were used to investigate the role of mitochondrial fission in butyrate metabolism. Enzyme activity assays were performed to identify the key proteins involved in this mechanism.

RESULTS

It was found that inhibition of mitochondrial fission promoted mucosal healing in mice and that there was an increase in mitochondrial fission in colonic epithelial cells of UC patients. Excessive fission inhibits stem cell proliferation by impairing butyrate metabolism in colonic organoids. The mitochondrial fission antagonist P110 failed to promote mucosal healing in antibiotic-treated mice, and the addition of exogenous butyrate reversed this effect. Increased butyrate exposure in the colonic stem cell niche has also been observed in UC patients. Mechanistically, enzyme activity assays on colonic organoids revealed that excessive fission inhibits mitochondrial acetoacetyl-CoA thiolase activity via reactive oxygen species.

CONCLUSIONS

Collectively, these data indicate that excessive mitochondrial fission suppresses mucosal repair by inhibiting butyrate metabolism and provides a potential target for mucosal healing in patients with ulcerative colitis.

Mitochondrial hyperfusion induces metabolic remodeling in lung endothelial cells by modifying the activities of electron transport chain complexes I and III

OBJECTIVE

Pulmonary hypertension (PH) is a progressive disease with vascular remodeling as a critical structural alteration. We have previously shown that metabolic reprogramming is an early initiating mechanism in animal models of PH. This metabolic dysregulation has been linked to remodeling the mitochondrial network to favor fission. However, whether the mitochondrial fission/fusion balance underlies the metabolic reprogramming found early in PH development is unknown.

METHODS

Utilizing a rat early model of PH, in conjunction with cultured pulmonary endothelial cells (PECs), we utilized metabolic flux assays, Seahorse Bioassays, measurements of electron transport chain (ETC) complex activity, fluorescent microscopy, and molecular approaches to investigate the link between the disruption of mitochondrial dynamics and the early metabolic changes that occur in PH.

RESULTS

We observed increased fusion mediators, including Mfn1, Mfn2, and Opa1, and unchanged fission mediators, including Drp1 and Fis1, in a two-week monocrotaline-induced PH animal model (early-stage PH). We were able to establish a connection between increases in fusion mediator Mfn1 and metabolic reprogramming. Using an adenoviral expression system to enhance Mfn1 levels in pulmonary endothelial cells and utilizing 13C-glucose labeled substrate, we found increased production of 13C lactate and decreased TCA cycle metabolites, revealing a Warburg phenotype. The use of a 13C5-glutamine substrate showed evidence that hyperfusion also induces oxidative carboxylation. The increase in glycolysis was linked to increased hypoxia-inducible factor 1α (HIF-1α) protein levels secondary to the disruption of cellular bioenergetics and higher levels of mitochondrial reactive oxygen species (mt-ROS). The elevation in mt-ROS correlated with attenuated ETC complexes I and III activities. Utilizing a mitochondrial-targeted antioxidant to suppress mt-ROS, limited HIF-1α protein levels, which reduced cellular glycolysis and reestablished mitochondrial membrane potential.

CONCLUSIONS

Our data connects mitochondrial fusion-mediated mt-ROS to the Warburg phenotype in early-stage PH development.

DRP1 Association in Inflammation and Metastasis: A Review

In recent years, mitochondria have gained significant interest in the field of biomedical research due to their impact on aging, human health, and other advanced findings in metabolic functions. The latest finding shows that metabolic interventions are a leading cause of several diseases, which has sparked interest in finding new therapeutic treatments. Apart from this, the unique inheritance of genetic material from mother to offspring can help scientists find ways to prevent mitochondrial inherited diseases. Additionally, the anti-aging benefits of controlling mitochondrial functions are also being researched. The present study aims to provide a cohesive overview of the latest findings in mitochondrial research, focusing on the role of DRP1 (Dynamin- related protein 1), a member of the GTPase family, in mediating mitochondrial fission. The first section of this paper provides a concise explanation of how DRP1 controls processes such as mitophagy and mitochondrial fission. Subsequently, the paper delves into the topic of inflammation, discussing the current findings regarding the inflammatory response mediated by DRP1. Finally, the role of mitochondrial fission mediated by DRP1 in cancer is examined, reviewing ongoing research on various types of cancer and their recurrence. Moreover, this review also covers the epigenetic regulation of mitochondrial fission. The studies were selected, and evaluated, and the information was collected to present an overview of the key findings. By exploring various aspects of research and potential links, we hope to contribute to a deeper understanding of the intricate relationship between the fields of cancer research and inflammation studies with respect to mitochondrial- based research.

Mitochondria as a sensor, a central hub and a biological clock in psychological stress-accelerated aging

The theory that oxidative damage caused by mitochondrial free radicals leads to aging has brought mitochondria into the forefront of aging research. Psychological stress that encompasses many different experiences and exposures across the lifespan has been identified as a catalyst for accelerated aging. Mitochondria, known for their dynamic nature and adaptability, function as a highly sensitive stress sensor and central hub in the process of accelerated aging. In this review, we explore how mitochondria as sensors respond to psychological stress and contribute to the molecular processes in accelerated aging by viewing mitochondria as hormonal, mechanosensitive and immune suborganelles. This understanding of the key role played by mitochondria and their close association with accelerated aging helps us to distinguish normal aging from accelerated aging, correct misconceptions in aging studies, and develop strategies such as exercise and mitochondria-targeted nutrients and drugs for slowing down accelerated aging, and also hold promise for prevention and treatment of age-related diseases.

Novel Relationship between Mitofusin 2-Mediated Mitochondrial Hyperfusion, Metabolic Remodeling, and Glycolysis in Pulmonary Arterial Endothelial Cells

The disruption of mitochondrial dynamics has been identified in cardiovascular diseases, including pulmonary hypertension (PH), ischemia-reperfusion injury, heart failure, and cardiomyopathy. Mitofusin 2 (Mfn2) is abundantly expressed in heart and pulmonary vasculature cells at the outer mitochondrial membrane to modulate fusion. Previously, we have reported reduced levels of Mfn2 and fragmented mitochondria in pulmonary arterial endothelial cells (PAECs) isolated from a sheep model of PH induced by pulmonary over-circulation and restoring Mfn2 normalized mitochondrial function. In this study, we assessed the effect of increased expression of Mfn2 on mitochondrial metabolism, bioenergetics, reactive oxygen species production, and mitochondrial membrane potential in control PAECs. Using an adenoviral expression system to overexpress Mfn2 in PAECs and utilizing 13C labeled substrates, we assessed the levels of TCA cycle metabolites. We identified increased pyruvate and lactate production in cells, revealing a glycolytic phenotype (Warburg phenotype). Mfn2 overexpression decreased the mitochondrial ATP production rate, increased the rate of glycolytic ATP production, and disrupted mitochondrial bioenergetics. The increase in glycolysis was linked to increased hypoxia-inducible factor 1α (HIF-1α) protein levels, elevated mitochondrial reactive oxygen species (mt-ROS), and decreased mitochondrial membrane potential. Our data suggest that disrupting the mitochondrial fusion/fission balance to favor hyperfusion leads to a metabolic shift that promotes aerobic glycolysis. Thus, therapies designed to increase mitochondrial fusion should be approached with caution.

Telomerase reverse transcriptase restores pancreatic microcirculation profiles and attenuates endothelial dysfunction by inhibiting mitochondrial superoxide production: A potential target for acute pancreatitis therapy

BACKGROUND

Acute pancreatitis (AP) is a potentially lethal disease related to prominent microcirculation dysfunction. Pancreatic microvascular endothelial dysfunction enhances oxidative stress with tissue damage. Increased superoxide production disrupts endothelial junction integrity and increases endothelial permeability. Endothelial mitochondrial ROS (mtROS) represent a major intracellular source of superoxide anions. The non-canonical function of telomerase reverse transcriptase (TERT) involves the maintenance of cellular redox homeostasis in somatic tissues.

METHODS

We investigated whether TERT restores microcirculation dysfunction and attenuates the endothelium injury by inhibiting superoxide production during AP progression. We established TERT transgenic and TERT knock-down mice and used cerulein (CER) and lipopolysaccharide (LPS) injections to induce AP models. In addition, we exposed HUVECs to LPS following TERT overexpression or silencing to explore the role of TERT in endothelial dysfunction. We also performed flow cytometry and confocal microscopy assays by using HUVECs. And a mtROS inhibitor, MitoTempo, was used to scavenge mitochondria superoxide and alkyl.

RESULTS

TERT transgenic mice were found to have restored pancreatic microcirculation profiles and microvascular endothelial morphology compared with wild-type mice under cerulein injection. In contrast, TERT silencing displayed the opposite effect in response to cerulein. Subsequently, we showed that TERT overexpression attenuates mtROS production and mitochondrial dysfunction during LPS-stimulated endothelial dysfunction. Furthermore, we found that TERT overexpression maintains the balance between mitochondrial contents and ATP level during endothelial dysfunction. In addition, the protective trend of MitoTempo is impeded after TERT silencing.

CONCLUSION

TERT restores pancreatic microcirculation dysfunction and attenuates microvascular endothelium lesions by inhibiting the increase of superoxide production and mitochondrial dysfunction.

Novel Morphological Profiling Assay Connects ex Vivo Endothelial Cell Responses to Disease Severity in Liver Cirrhosis

Background and Aims

Endothelial cell (EC) dysfunction in response to circulating plasma factors is a known causal factor in many systemic diseases. However, no appropriate assay is available to investigate this causality ex vivo. In liver cirrhosis, systemic inflammation is identified as central mechanism in progression from compensated to decompensated cirrhosis (DC), but the role of ECs therein is unknown. We aimed to develop a novel ex vivo assay for assessing EC responses to patient-derived plasma (PDP) and assess the potential of this assay in a cohort of liver cirrhosis patients.

Methods

Image-based morphological profiling was utilized to assess the impact of PDP on cultured ECs. Endothelial cell (EC) monolayers were exposed to 25% stabilized PDP (20 compensated cirrhoses, 20 DCs, and 20 healthy controls (HCs). Single-cell morphological profiles were extracted by automated image-analysis following staining of multiple cellular components and high-content imaging. Patient profiles were created by dimension reduction and cell-to-patient data aggregation, followed by multivariate-analysis to stratify patients and identify discriminating features.

Results

Patient-derived plasma (PDP) exposure induced profound changes in EC morphology, displaying clear differences between controls and DC patients. Compensated cirrhosis patients showed overlap with healthy controls and DC patients. Supervised analysis showed Child-Pugh (CP) class could be predicted from EC morphology. Most importantly, CP-C patients displayed distinct EC phenotypes, in which mitochondrial changes were most discriminative.

Conclusion

Morphological profiling presents a viable tool to assess the endothelium ex vivo. We demonstrated that the EC phenotype corresponds with disease severity in liver cirrhosis. Moreover, our results suggest the presence of mitochondrial dysfunction in ECs of CP-C patient.

SPECT/CT imaging for tracking subendothelial retention of electronegative low-density lipoprotein in vivo

The fifth subfraction of low-density lipoprotein (L5 LDL) can be separated from human LDL using fast-protein liquid chromatography with an anion exchange column. L5 LDL induces vascular endothelial injury both in vitro and in vivo through the lectin-like oxidized LDL receptor-1 (LOX-1). However, no in vivo evidence shows the tendency of L5 LDL deposition on vascular endothelium and links to dysfunction. This study aimed to investigate L5 LDL retention in vivo using SPECT/CT imaging, with Iodine-131 (131I)-labeled and injected into six-month-old apolipoprotein E knockout (apoE-/-) mice through tail veins. Besides, we examined the biodistribution of L5 LDL in tissues and analyzed the intracellular trafficking in human aortic endothelial cells (HAoECs) by confocal microscopy. The impacts of L5 LDL on HAoECs were analyzed using electron microscopy for mitochondrial morphology and western blotting for signaling. Results showed 131I-labeled-L5 was preferentially deposited in the heart and vessels compared to L1 LDL. Furthermore, L5 LDL was co-localized with the mitochondria and associated with mitofusin (MFN1/2) and optic atrophy protein 1 (OPA1) downregulation, leading to mitochondrial fission. In summary, L5 LDL exhibits a propensity for subendothelial retention, thereby promoting endothelial dysfunction and the formation of atherosclerotic lesions.

The role of mitochondrial dysfunction in periodontitis: From mechanisms to therapeutic strategy

Periodontitis is an inflammatory and destructive disease of tooth-supporting tissue and has become the leading cause of adult tooth loss. The most central pathological features of periodontitis are tissue damage and inflammatory reaction. As the energy metabolism center of eukaryotic cells, mitochondrion plays a notable role in various processes, such as cell function and inflammatory response. When the intracellular homeostasis of mitochondrion is disrupted, it can lead to mitochondrial dysfunction and inability to generate adequate energy to maintain basic cellular biochemical reactions. Recent studies have revealed that mitochondrial dysfunction is closely related to the initiation and development of periodontitis. The excessive production of mitochondrial reactive oxygen species, imbalance of mitochondrial biogenesis and dynamics, mitophagy and mitochondrial DNA damage can all affect the development and progression of periodontitis. Thus, targeted mitochondrial therapy is potentially promising in periodontitis treatment. In this review, we summarize the above mitochondrial mechanism in the pathogenesis of periodontitis and discuss some potential approaches that can exert therapeutic effects on periodontitis by modulating mitochondrial activity. The understanding and summary of mitochondrial dysfunction in periodontitis might provide new research directions for pathological intervention or treatment of periodontitis.

Current Advances of Mitochondrial Dysfunction and Cardiovascular Disease and Promising Therapeutic Strategies

Mitochondria are cellular power stations and essential organelles for maintaining cellular homeostasis. Dysfunctional mitochondria have emerged as a key factor in the occurrence and development of cardiovascular disease. This review focuses on advances in the relationship between mitochondrial dysfunction and cardiovascular diseases such as atherosclerosis, heart failure, myocardial ischemia reperfusion injury, and pulmonary arterial hypertension. The clinical value and challenges of mitochondria-targeted strategies, including mitochondria-targeted antioxidants, mitochondrial quality control modulators, mitochondrial function protectors, mitochondrial biogenesis promoters, and recently developed mitochondrial transplants, are also discussed.

Hydrogen Protection Boosts the Bioactivity of Chrysanthemum morifolium Extract in Preventing Palmitate-Induced Endothelial Dysfunction by Restoring MFN2 and Alleviating Oxidative Stress in HAEC Cells

As the most important natural antioxidants in plant extracts, polyphenols demonstrate versatile bioactivities and are susceptible to oxidation. The commonly used ultrasonic extraction often causes oxidation reactions involving the formation of free radicals. To minimize the oxidation effects during the ultrasonic extraction process, we designed a hydrogen (H₂)-protected ultrasonic extraction method and used it in Chrysanthemum morifolium extraction. Hydrogen-protected extraction improved the total antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and polyphenol content of Chrysanthemum morifolium water extract (CME) compared with air and nitrogen (N₂) conditions. We further investigated the protective effects and mechanisms of CME on palmitate (PA)-induced endothelial dysfunction in human aorta endothelial cells (HAECs). We found that hydrogen-protected CME (H₂-CME) best-prevented impairment in nitric oxide (NO) production, endothelial NO synthase (eNOS) protein level, oxidative stress, and mitochondrial dysfunction. In addition, H₂-CME prevented PA-induced endothelial dysfunction by restoring mitofusin-2 (MFN2) levels and maintaining redox balance.

Insights into SGLT2 inhibitor treatment of diabetic cardiomyopathy: focus on the mechanisms

Among the complications of diabetes, cardiovascular events and cardiac insufficiency are considered two of the most important causes of death. Experimental and clinical evidence supports the effectiveness of SGLT2i for improving cardiac dysfunction. SGLT2i treatment benefits metabolism, microcirculation, mitochondrial function, fibrosis, oxidative stress, endoplasmic reticulum stress, programmed cell death, autophagy, and the intestinal flora, which are involved in diabetic cardiomyopathy. This review summarizes the current knowledge of the mechanisms of SGLT2i for the treatment of diabetic cardiomyopathy.

Human Brain Microvascular Endothelial Cells Exposure to SARS-CoV-2 Leads to Inflammatory Activation through NF-κB Non-Canonical Pathway and Mitochondrial Remodeling

Neurological effects of COVID-19 and long-COVID-19, as well as neuroinvasion by SARS-CoV-2, still pose several questions and are of both clinical and scientific relevance. We described the cellular and molecular effects of the human brain microvascular endothelial cells (HBMECs) in vitro exposure by SARS-CoV-2 to understand the underlying mechanisms of viral transmigration through the blood-brain barrier. Despite the low to non-productive viral replication, SARS-CoV-2-exposed cultures displayed increased immunoreactivity for cleaved caspase-3, an indicator of apoptotic cell death, tight junction protein expression, and immunolocalization. Transcriptomic profiling of SARS-CoV-2-challenged cultures revealed endothelial activation via NF-κB non-canonical pathway, including RELB overexpression and mitochondrial dysfunction. Additionally, SARS-CoV-2 led to altered secretion of key angiogenic factors and to significant changes in mitochondrial dynamics, with increased mitofusin-2 expression and increased mitochondrial networks. Endothelial activation and remodeling can further contribute to neuroinflammatory processes and lead to further BBB permeability in COVID-19.

Mitochondrial dynamics in vascular remodeling and target-organ damage

Vascular remodeling is the pathological basis for the development of many cardiovascular diseases. The mechanisms underlying endothelial cell dysfunction, smooth muscle cell phenotypic switching, fibroblast activation, and inflammatory macrophage differentiation during vascular remodeling remain elusive. Mitochondria are highly dynamic organelles. Recent studies showed that mitochondrial fusion and fission play crucial roles in vascular remodeling and that the delicate balance of fusion-fission may be more important than individual processes. In addition, vascular remodeling may also lead to target-organ damage by interfering with the blood supply to major body organs such as the heart, brain, and kidney. The protective effect of mitochondrial dynamics modulators on target-organs has been demonstrated in numerous studies, but whether they can be used for the treatment of related cardiovascular diseases needs to be verified in future clinical studies. Herein, we summarize recent advances regarding mitochondrial dynamics in multiple cells involved in vascular remodeling and associated target-organ damage.

Modulation of the mitochondrial Ca2+ uniporter complex subunit expression by different shear stress patterns in vascular endothelial cells

Mitochondrial calcium (m Ca2+ ) uptake occurs via the Mitochondrial Ca2+ Uniporter (MCU) complex and plays a critical role in mitochondrial dynamics, mitophagy, and apoptosis. MCU complex activity is in part modulated by the expression of its regulatory subunits. Cardiovascular disease models demonstrated altered gene/protein expression of one or multiple subunits in different cells, including vascular endothelial cells (ECs). MCU complex activity was found necessary for stable flow (s-flow)-induced mitophagy and promotion of an atheroprotective EC phenotype. Disturbed flow (d-flow) is known to lead to an atheroprone phenotype. Despite the role of MCU in flow-regulated EC function, flow-induced alterations in MCU complex subunit expression are currently unknown. We exposed cultured human ECs to atheroprotective (steady shear stress, SS) or atheroprone flow (oscillatory shear stress, OS) and measured mRNA and protein levels of the MCU complex members. SS and OS differentially modulated subunit expression at gene/protein levels. Protein expression changes of the core MCU, m Ca2+ uptake 1 (MICU1) and MCU regulator 1 (MCUR1) subunits in SS- and OS-exposed, compared to static, ECs suggested an enhanced m Ca2+ influx under each flow and a potential contribution to EC dysfunction under OS. In silico analysis of a single-cell RNA-sequencing dataset was employed to extract transcript values of MCU subunits in mouse carotid ECs from regions exposed to s-flow or d-flow. Mcu and Mcur1 genes showed significant differences in expression after prolonged exposure to each flow. The differential expression of MCU complex subunits indicated a tight regulation of the complex activity under physiological and pathological hemodynamic conditions.

OPA1 supports mitochondrial dynamics and immune evasion to CD8+ T cell in lung adenocarcinoma

Background

Mitochondrial fusion and fission were identified to play key roles during multiple biology process. Thus, we aim to investigate the roles of OPA1 in mitochondria fusion and immune evasion of non-small cell lung cancer cells.

Methods

The transcriptional activation of genes related to mitochondrial dynamics was determined by using multi-omics data in lung adenocarcinoma (LUAD). We elucidated the molecular mechanism and roles of OPA1 promoting lung cancer through single-cell sequencing and molecular biological experiments.

Results

Here, we found that copy number amplification of OPA1 and MFN1 were co-occurring and synergistically activated in tumor epithelial cells in lung cancer tissues. Both of OPA1 and MFN1 were highly expressed in LUAD tumor tissues and OPA1 high expression was associated with poor prognosis. In terms of mechanism, the damaged mitochondria activated the apoptotic signaling pathways, inducing cell cycle arrest and cell apoptosis. More interestingly, OPA1 deficiency damaged mitochondrial dynamics and further blocked the respiratory function to increase the sensitivity of tumor epithelial to CD8⁺ T cells in non-small cell lung cancer.

Conclusions

Our study demonstrated the high co-occurrence of copy number amplification and co-expression of OPA1 and MFN1 in LUAD tissue, and further revealed the contribution of OPA1 in maintaining the mitochondria respiratory function and the ability of immune evasion to CD8⁺ T cells of LUAD.

Mitochondrial dysfunction in vascular endothelial cells and its role in atherosclerosis

The mitochondria are essential organelles that generate large amounts of ATP via the electron transport chain (ECT). Mitochondrial dysfunction causes reactive oxygen species accumulation, energy stress, and cell death. Endothelial mitochondrial dysfunction is an important factor causing abnormal function of the endothelium, which plays a central role during atherosclerosis development. Atherosclerosis-related risk factors, including high glucose levels, hypertension, ischemia, hypoxia, and diabetes, promote mitochondrial dysfunction in endothelial cells. This review summarizes the physiological and pathophysiological roles of endothelial mitochondria in endothelial function and atherosclerosis.

Mitochondrial fission in hepatocytes as a potential therapeutic target for nonalcoholic steatohepatitis

AIM

The mitochondria are highly plastic and dynamic organelles; mitochondrial dysfunction has been reported to play causative roles in diabetes, cardiovascular diseases, and nonalcoholic fatty liver disease (NAFLD). However, the relationship between mitochondrial fission and NAFLD pathogenesis remains unknown. We aimed to investigate whether alterations in mitochondrial fission could play a role in the progression of NAFLD.

METHODS

Mice were fed a standard diet or choline-deficient, L-amino acid-defined (CDAA) diet with vehicle or mitochondrial division inhibitor-1.

RESULTS

Substantial enhancement of mitochondrial fission in hepatocytes was triggered by 4 weeks of feeding and was associated with changes reflecting the early stage of human nonalcoholic steatohepatitis (NASH), steatotic change with liver inflammation, and hepatocyte ballooning. Excessive mitochondrial fission inhibition in hepatocytes and lipid metabolism dysregulation in adipose tissue attenuated liver inflammation and fibrogenesis but not steatosis and the systemic pathological changes in the early and chronic fibrotic NASH stages (4- and 12-week CDAA feeding). These beneficial changes due to the suppression of mitochondrial fission against the liver and systemic injuries were associated with decreased autophagic responses and endoplasmic reticulum stress in hepatocytes. Injuries to other liver cells, such as endothelial cells, Kupffer cells, and hepatic stellate cells, were also attenuated by the inhibition of mitochondrial fission in hepatocytes.

CONCLUSIONS

Taken together, these findings suggest that excessive mitochondrial fission in hepatocytes could play a causative role in NAFLD progression by liver inflammation and fibrogenesis through altered cell cross-talk. This study provides a potential therapeutic target for NAFLD.

The role of mitochondrial fission in cardiovascular health and disease

Mitochondria are organelles involved in the regulation of various important cellular processes, ranging from ATP generation to immune activation. A healthy mitochondrial network is essential for cardiovascular function and adaptation to pathological stressors. Mitochondria undergo fission or fusion in response to various environmental cues, and these dynamic changes are vital for mitochondrial function and health. In particular, mitochondrial fission is closely coordinated with the cell cycle and is linked to changes in mitochondrial respiration and membrane permeability. Another key function of fission is the segregation of damaged mitochondrial components for degradation by mitochondrial autophagy (mitophagy). Mitochondrial fission is induced by the large GTPase dynamin-related protein 1 (DRP1) and is subject to sophisticated regulation. Activation requires various post-translational modifications of DRP1, actin polymerization and the involvement of other organelles such as the endoplasmic reticulum, Golgi apparatus and lysosomes. A decrease in mitochondrial fusion can also shift the balance towards mitochondrial fission. Although mitochondrial fission is necessary for cellular homeostasis, this process is often aberrantly activated in cardiovascular disease. Indeed, strong evidence exists that abnormal mitochondrial fission directly contributes to disease development. In this Review, we compare the physiological and pathophysiological roles of mitochondrial fission and discuss the therapeutic potential of preventing excessive mitochondrial fission in the heart and vasculature.

Adipose stromal vascular fraction reverses mitochondrial dysfunction and hyperfission in aging-induced coronary microvascular disease

Aging is associated with blunted coronary microvascular vasodilatory function. Previously, systemically administered adipose stromal vascular fraction (SVF) therapy reversed aging-induced attenuation of β1-adrenergic- and flow-mediated dilation dependent on reducing mitochondrial reactive oxygen species. We hypothesized that SVF-mediated recovery of microvascular dilatory function is dependent on recovery of mitochondrial function, specifically by reducing mitochondrial hyperfission. Female Fischer-344 rats were allocated into young control, old control, and old + SVF therapy groups. Pressure myography, immunofluorescent staining, Western blot analysis, and RNA sequencing were performed to determine coronary microvascular mitochondrial dynamics and function. Gene and protein expression of fission-mediator DRP-1 was enhanced with aging but reversed by SVF therapy. SVF facilitated an increase in fusion-mediator MFN-1 gene and protein expression. Mitochondrial morphology was characterized as rod-like and densely networked in young controls, isolated circular and punctate with aging, and less circularity with partially restored mitochondrial branch density with SVF therapy. Decreased mitochondrial membrane potential and ATP bioavailability in aged animals at baseline and during flow-mediated dilation were reversed by SVF and accompanied with enhanced oxygen consumption. Dilation to norepinephrine and flow in young controls were dependent on uninhibited mitochondrial fusion, whereas inhibiting fission did not restore aged microvessel response to norepinephrine or flow. SVF-mediated recovery of β-adrenergic function was dependent on uninhibited mitochondrial fusion, whereas recovery of flow-mediated dilation was dependent on maintained mitochondrial fission. Impaired dilation in aging is mitigated by SVF therapy, which recovers mitochondrial function and fission/fusion balance.NEW & NOTEWORTHY We elucidated the consequences of aging on coronary microvascular mitochondrial health as well as SVF's ability to reverse these effects. Aging shifts gene/protein expression and mitochondrial morphology indicating hyperfission, alongside attenuated mitochondrial membrane potential and ATP bioavailability, all reversed using SVF therapy. Mitochondrial membrane potential and ATP levels correlated with vasodilatory efficiency. Mitochondrial dysfunction is a contributing pathological factor in aging that can be targeted by therapeutic SVF to preserve microvascular dilative function.

Swimming Exercise Alleviates Endothelial Mitochondrial Fragmentation via Inhibiting Dynamin-Related Protein-1 to Improve Vascular Function in Hypertension

BACKGROUND

Regular exercise has been recommended clinically for all individuals to protect against hypertension but the underlying mechanisms are not fully elucidated. We recently found a significant mitochondrial fragmentation in the vascular endothelium of hypertensive human subjects. In this study, we investigated whether exercise could restore endothelial mitochondrial dynamics and thus improve vascular function in hypertension.

METHODS

Vascular endothelial mitochondrial morphological alterations were examined in patients with hypertension and hypertensive animal models. Furthermore, swimming exercise-induced endothelial mitochondrial dynamics and vascular function changes were investigated in spontaneously hypertensive rats (SHRs).

RESULTS

Mitochondrial fragmentation with an elevated mitochondrial fission mediator Drp1 (dynamin-related protein-1) was observed in the mesenteric artery endothelium from hypertensive patients. A similar mitochondrial fragmentation with increased Drp1 expression were exhibited in the aortic endothelium of angiotensin II-induced hypertensive mice and SHRs. Interestingly, swimming exercise significantly reduced vascular Drp1 expression and alleviated endothelial mitochondrial fragmentation, thus improving blood pressure in SHRs. In cultured endothelial cells, angiotensin II exposure induced Drp1 upregulation, mitochondrial fragmentation and dysfunction, and reduced nitric oxide production, which was blunted by Drp1 genetic reduction or its inhibitor Mdivi-1. Mdivi-1 administration also ameliorated endothelial mitochondrial fragmentation, vascular dysfunction and blood pressure elevation in SHRs while swimming exercise plus Mdivi-1 treatment provided no additional benefits, suggesting that Drp1 inhibition may partially contribute to swimming exercise-conferred anti-hypertensive effects.

CONCLUSIONS

These findings suggest that swimming exercise alleviates endothelial mitochondrial fragmentation via inhibiting Drp1, which may contribute to exercise-induced improvement of vascular function and blood pressure in hypertension.

Therapeutic strategies in ischemic cardiomyopathy: Focus on mitochondrial quality surveillance

Despite considerable efforts to prevent and treat ischemic cardiomyopathy (ICM), effective therapies remain lacking, in part owing to the complexity of the underlying molecular mechanisms, which are not completely understood yet. It is now widely thought that mitochondria serve as “sentinel” organelles that are capable of detecting cellular injury and integrating multiple stress signals. These pathophysiological activities are temporally and spatially governed by the mitochondrial quality surveillance (MQS) system, involving mitochondrial dynamics, mitophagy, and biogenesis. Dysregulation of MQS is an early and critical process contributing to mitochondrial bioenergetic dysfunction and sublethal injury to cardiomyocytes during ICM. An improved understanding of the pathogenesis of ICM may enable the development of novel preventive and therapeutic strategies aimed at overcoming the challenge of myocardial ischemia and its cardiovascular sequelae. This review describes recent research on the protective effects of MQS in ICM and highlights promising therapeutic targets.

Restoration of Mitochondrial Function Is Essential in the Endothelium-Dependent Vasodilation Induced by Acacetin in Hypertensive Rats

Mitochondrial dysfunction in the endothelium contributes to the progression of hypertension and plays an obligatory role in modulating vascular tone. Acacetin is a natural flavonoid compound that has been shown to possess multiple beneficial effects, including vasodilatation. However, whether acacetin could improve endothelial function in hypertension by protecting against mitochondria-dependent apoptosis remains to be determined. The mean arterial pressure (MAP) in Wistar Kyoto (WKY) rats, spontaneously hypertensive rats (SHR) administered with acacetin intraperitoneally for 2 h or intragastrically for six weeks were examined. The endothelial injury was evaluated by immunofluorescent staining and a transmission electron microscope (TEM). Vascular tension measurement was performed to assess the protective effect of acacetin on mesenteric arteries. Endothelial injury in the pathogenesis of SHR was modeled in HUVECs treated with Angiotensin II (Ang II). Mitochondria-dependent apoptosis, the opening of Mitochondrial Permeability Transition Pore (mPTP) and mitochondrial dynamics proteins were determined by fluorescence activated cell sorting (FACS), immunofluorescence staining and western blot. Acacetin administered intraperitoneally greatly reduced MAP in SHR by mediating a more pronounced endothelium-dependent dilatation in mesenteric arteries, and the vascular dilatation was reduced remarkably by NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis. While acacetin administered intragastrically for six weeks had no apparent effect on MAP, it improved the endothelium-dependent dilatation in SHR by activating the AKT/eNOS pathway and protecting against the abnormalities of endothelium and mitochondria. Furthermore, acacetin remarkably inhibited Ang II induced apoptosis by inhibiting the increased expression of Cyclophilin D (CypD), promoted the opening of mPTP, ROS generation, ATP loss and disturbance of dynamin-related protein 1 (DRP1)/optic atrophy1 (OPA1) dynamics in HUVECs. This study suggests that acacetin protected against endothelial dysfunction in hypertension by activating the AKT/eNOS pathway and modulating mitochondrial function by targeting mPTP and DRP1/OPA1-dependent dynamics.

The Mitochondrial Unfolded Protein Response: A Novel Protective Pathway Targeting Cardiomyocytes

Mitochondrial protein homeostasis in cardiomyocyte injury determines not only the normal operation of mitochondrial function but also the fate of mitochondria in cardiomyocytes. Studies of mitochondrial protein homeostasis have become an integral part of cardiovascular disease research. Modulation of the mitochondrial unfolded protein response (UPRmt), a protective factor for cardiomyocyte mitochondria, may in the future become an important treatment strategy for myocardial protection in cardiovascular disease. However, because of insufficient understanding of the UPRmt and inadequate elucidation of relevant mechanisms, few therapeutic drugs targeting the UPRmt have been developed. The UPRmt maintains a series of chaperone proteins and proteases and is activated when misfolded proteins accumulate in the mitochondria. Mitochondrial injury leads to metabolic dysfunction in cardiomyocytes. This paper reviews the relationship of the UPRmt and mitochondrial quality monitoring with cardiomyocyte protection. This review mainly introduces the regulatory mechanisms of the UPRmt elucidated in recent years and the relationship between the UPRmt and mitophagy, mitochondrial fusion/fission, mitochondrial biosynthesis, and mitochondrial energy metabolism homeostasis in order to generate new ideas for the study of the mitochondrial protein homeostasis mechanisms as well as to provide a reference for the targeted drug treatment of imbalances in mitochondrial protein homeostasis following cardiomyocyte injury.

Research progress on ncRNAs regulation of mitochondrial dynamics in diabetes

Diabetes mellitus and its complications are major health concerns worldwide that should be routinely monitored for evaluating disease progression. And there is currently much evidence to suggest a critical role for mitochondria in the common pathogenesis of diabetes and its complications. Mitochondrial dynamics are involved in the development of diabetes through mediating insulin signaling and insulin resistance, and in the development of diabetes and its complications through mediating endothelial impairment and other closely related pathophysiological mechanisms of diabetic cardiomyopathy (DCM). noncoding RNAs (ncRNAs) are closely linked to mitochondrial dynamics by regulating the expression of mitochondrial dynamic-associated proteins, or by regulating key proteins in related signaling pathways. Therefore, this review summarizes the research progress on the regulation of Mitochondrial Dynamics by ncRNAs in diabetes and its complications, which is a promising area for future antibodies or targeted drug development.

LncRNA ANRIL mediates endothelial dysfunction through BDNF downregulation in chronic kidney disease

Endothelial dysfunction is common in patients with chronic kidney disease (CKD), but the mechanism is unknown. In this study, we found that the circulating ANRIL level was increased and correlated with vascular endothelial dysfunction in patients with CKD, also negatively correlated with plasma brain-derived neurotrophic factor (BDNF) concentration. We constructed the ANRIL knockout mice model, and found that ANRIL deficiency reversed the abnormal expression of BDNF, along with endothelial nitric oxide synthase (eNOS), vascular adhesion molecule 1 (VCAM-1) and Von Willebrand factor (vWF). Meanwhile, mitochondrial dynamics-related proteins, Dynamin-related protein 1 (Drp1) and mitofusins (Mfn2) level were also recovered. In addition, in vitro, serum derived from CKD patients and uremia toxins induced abnormal expression of ANRIL. By making use of the gain- and loss-of-function approaches, we observed that ANRIL mediated endothelial dysfunction through BDNF downregulation. To explore the specific mechanism, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) were used to explore the binding of ANRIL to histone methyltransferase Enhancer of zeste homolog 2 (EZH2). Further experiments found increased EZH2 and histone H3 lysine 27 trimethylation (H3K27me3) levels at the BDNF promoter region. Collectively, we demonstrated that ANRIL mediate BDNF transcriptional suppression through recruitment of EZH2 to the BDNF promoter region, then regulated the proteins expression related to endothelial function and mitochondrial dynamics. This study provides new insights for the study of endothelial dysfunction in CKD.

SARS-CoV-2 infection of human brain microvascular endothelial cells leads to inflammatory activation through NF-κB non-canonical pathway and mitochondrial remodeling

Neurological effects of COVID-19 and long-COVID-19 as well as neuroinvasion by SARS-CoV-2 still pose several questions and are of both clinical and scientific relevance. We described the cellular and molecular effects of the human brain microvascular endothelial cells (HBMECs) in vitro infection by SARS-CoV-2 to understand the underlying mechanisms of viral transmigration through the Blood-Brain Barrier. Despite the low to non-productive viral replication, SARS-CoV-2-infected cultures displayed increased apoptotic cell death and tight junction protein expression and immunolocalization. Transcriptomic profiling of infected cultures revealed endothelial activation via NF-κB non-canonical pathway, including RELB overexpression, and mitochondrial dysfunction. Additionally, SARS-CoV-2 led to altered secretion of key angiogenic factors and to significant changes in mitochondrial dynamics, with increased mitofusin-2 expression and increased mitochondrial networks. Endothelial activation and remodeling can further contribute to neuroinflammatory processes and lead to further BBB permeability in COVID-19.

SARS-CoV-2 infection of human brain microvascular endothelial cells leads to inflammatory activation through NF-κB non-canonical pathway and mitochondrial remodeling

Neurological effects of COVID-19 and long-COVID-19 as well as neuroinvasion by SARS-CoV-2 still pose several questions and are of both clinical and scientific relevance. We described the cellular and molecular effects of the human brain microvascular endothelial cells (HBMECs) in vitro infection by SARS-CoV-2 to understand the underlying mechanisms of viral transmigration through the Blood-Brain Barrier. Despite the low to non- productive viral replication, SARS-CoV-2-infected cultures displayed increased apoptotic cell death and tight junction protein expression and immunolocalization. Transcriptomic profiling of infected cultures revealed endothelial activation via NF-κB non-canonical pathway, including RELB overexpression, and mitochondrial dysfunction. Additionally, SARS-CoV-2 led to altered secretion of key angiogenic factors and to significant changes in mitochondrial dynamics, with increased mitofusin-2 expression and increased mitochondrial networks. Endothelial activation and remodeling can further contribute to neuroinflammatory processes and lead to further BBB permeability in COVID-19.

Altered Mitochondrial Opa1-Related Fusion in Mouse Promotes Endothelial Cell Dysfunction and Atherosclerosis

Flow (shear stress)-mediated dilation (FMD) of resistance arteries is a rapid endothelial response involved in tissue perfusion. FMD is reduced early in cardiovascular diseases, generating a major risk factor for atherosclerosis. As alteration of mitochondrial fusion reduces endothelial cells’ (ECs) sprouting and angiogenesis, we investigated its role in ECs responses to flow. Opa1 silencing reduced ECs (HUVECs) migration and flow-mediated elongation. In isolated perfused resistance arteries, FMD was reduced in Opa1^+/− mice, a model of the human disease due to Opa1 haplo-insufficiency, and in mice with an EC specific Opa1 knock-out (EC-Opa1). Reducing mitochondrial oxidative stress restored FMD in EC-Opa1 mice. In isolated perfused kidneys from EC-Opa1 mice, flow induced a greater pressure, less ATP, and more H₂O₂ production, compared to control mice. Opa1 expression and mitochondrial length were reduced in ECs submitted in vitro to disturbed flow and in vivo in the atheroprone zone of the mouse aortic cross. Aortic lipid deposition was greater in Ldlr^−/--Opa1^+/- and in Ldlr^−/--EC-Opa1 mice than in control mice fed with a high-fat diet. In conclusion, we found that reduction in mitochondrial fusion in mouse ECs altered the dilator response to shear stress due to excessive superoxide production and induced greater atherosclerosis development.

Novel Insights into the Cardioprotective Effects of Calcitriol in Myocardial Infarction

BACKGROUND

Increasing evidence indicates that vitamin D deficiency negatively affects the cardiovascular system. Here we studied the therapeutic effects of calcitriol in myocardial infarction (MI) and investigated its underlying mechanisms.

METHODS

A MI model of Kun-ming mice induced by left anterior descending coronary artery ligation was utilized to study the potential therapeutic effects of calcitriol on MI. AC16 human cardiomyocyte-like cells treated with TNF-α were used for exploring the mechanisms that underlie the cardioprotective effects of calcitriol.

RESULTS

We observed that calcitriol reversed adverse cardiovascular function and cardiac remodeling in post-MI mice. Mechanistically, calcitriol suppressed MI-induced cardiac inflammation, ameliorated cardiomyocyte death, and promoted cardiomyocyte proliferation. Specifically, calcitriol exerted these cellular effects by upregulating Vitamin D receptor (VDR). Increased VDR directly interacted with p65 and retained p65 in cytoplasm, thereby dampening NF-κB signaling and suppressing inflammation. Moreover, up-regulated VDR was translocated into nuclei where it directly bound to IL-10 gene promoters to activate IL-10 gene transcription, further inhibiting inflammation.

CONCLUSION

We provide new insights into the cellular and molecular mechanisms underlying the cardioprotective effects of calcitriol, and we present comprehensive evidence to support the preventive and therapeutic effects of calcitriol on MI.