Mitofusins are required for angiogenic function and modulate different signaling pathways in cultured endothelial cells

Subcellular localization and function analysis of PINK1 mitron in PD progression: Mitron modulates mitochondrial morphology to regulate neuronal death

Parkinson's disease (PD) is a multifactorial neurodegenerative disorder. Loss or degeneration of the dopaminergic neurons in the substantia nigra and development of Lewy bodies in dopaminergic neurons were the defining pathologic changes. MiRNAs fine-tune the protein levels by posttranscriptional gene regulation. MiR-7019-3p is encoded within the fifth intron of PD-associated protein PINK1. In present study, we firstly demonstrated miR-7019-3p expression is significantly upregulated in PD mice model and neuron cell models, miR-7019-3p mainly existed in mitochondria, miR-7019-3p could regulate the structure, and function of mitochondria in neuronal cells. We predicted and verified that mitochondria-associated protein optic atrophy 1 and 12s rRNA, 16s rRNA, and polycistronic RNA are target genes of miR-7019-3p. Finally, we proved that SP1 protein could independently regulate the expression of miR-7019-3p at the upstream. The evidences in the study suggest the role miR-7019-3p in the regulation of mitochondrial structure and function, and this kind of regulation could be implemented or promoted through the pathway of SP1-miR-7019-3p-optic atrophy 1/12s rRNA, 16s rRNA, and polycistronic RNA. Our results have suggested a promising and potential therapeutic target for reversing mitochondria dysregulation in neuronal cells during PD process.

Identification of the central role of RNA polymerase mitochondrial for angiogenesis

Mitochondria are central to endothelial cell activation and angiogenesis, with the RNA polymerase mitochondrial (POLRMT) serving as a key protein in regulating mitochondrial transcription and oxidative phosphorylation. In our study, we examined the impact of POLRMT on angiogenesis and found that its silencing or knockout (KO) in human umbilical vein endothelial cells (HUVECs) and other endothelial cells resulted in robust anti-angiogenic effects, impeding cell proliferation, migration, and capillary tube formation. Depletion of POLRMT led to impaired mitochondrial function, characterized by mitochondrial depolarization, oxidative stress, lipid oxidation, DNA damage, and reduced ATP production, along with significant apoptosis activation. Conversely, overexpressing POLRMT promoted angiogenic activity in the endothelial cells. In vivo experiments demonstrated that endothelial knockdown of POLRMT, by intravitreous injection of endothelial specific POLRMT shRNA adeno-associated virus, inhibited retinal angiogenesis. In addition, inhibiting POLRMT with a first-in-class inhibitor IMT1 exerted significant anti-angiogenic impact in vitro and in vivo. Significantly elevated expression of POLRMT was observed in the retinal tissues of streptozotocin-induced diabetic retinopathy (DR) mice. POLRMT endothelial knockdown inhibited pathological retinal angiogenesis and mitigated retinal ganglion cell (RGC) degeneration in DR mice. At last, POLRMT expression exhibited a substantial increase in the retinal proliferative membrane tissues of human DR patients. These findings collectively establish the indispensable role of POLRMT in angiogenesis, both in vitro and in vivo.

Endothelial Drp1 Couples VEGF-induced Redox Signaling with Glycolysis Through Cysteine Oxidation to Drive Angiogenesis

Angiogenesis plays a vital role for postnatal development and tissue repair following ischemia. Reactive oxygen species (ROS) generated by NADPH oxidases (NOXes) and mitochondria act as signaling molecules that promote angiogenesis in endothelial cells (ECs) which mainly relies on aerobic glycolysis for ATP production. However, the connections linking redox signaling with glycolysis are not well understood. The GTPase Drp1 is a member of the dynamin superfamily that moves from cytosol to mitochondria through posttranslational modifications to induce mitochondrial fission. The role of Drp1 in ROS-dependent VEGF signaling and angiogenesis in ECs has not been previously described. Here, we identify an unexpected function of endothelial Drp1 as a redox sensor, transmitting VEGF-induced H 2 O 2 signals to enhance glycolysis and angiogenesis. Loss of Drp1 expression in ECs inhibited VEGF-induced angiogenic responses. Mechanistically, VEGF rapidly induced the NOX4-dependent sulfenylation (CysOH) of Drp1 on Cys 644 , promoting disulfide bond formation with the metabolic kinase AMPK and subsequent sulfenylation of AMPK at Cys 299 / 304 via the mitochondrial fission-mitoROS axis. This cysteine oxidation of AMPK, in turn, enhanced glycolysis and angiogenesis. In vivo , mice with EC-specific Drp1 deficiency or CRISPR/Cas9-engineered "redox-dead" (Cys to Ala) Drp1 knock-in mutations exhibited impaired retinal angiogenesis and post-ischemic neovascularization. Our findings uncover a novel role for endothelial Drp1 in linking VEGF-induced mitochondrial redox signaling to glycolysis through a cysteine oxidation-mediated Drp1-AMPK redox relay, driving both developmental and reparative angiogenesis.

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.

Biodegradable Zn-5Dy Alloy with Enhanced Osteo/Angio-Genic Activity and Osteointegration Effect via Regulation of SIRT4-Dependent Mitochondrial Function

Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.

Angiogenic activity of mitochondria; beyond the sole bioenergetic organelle

Angiogenesis is a complex process that involves the expansion of the pre-existing vascular plexus to enhance oxygen and nutrient delivery and is stimulated by various factors, including hypoxia. Since the process of angiogenesis requires a lot of energy, mitochondria play an important role in regulating and promoting this phenomenon. Besides their roles as an oxidative metabolism base, mitochondria are potential bioenergetics organelles to maintain cellular homeostasis via sensing alteration in oxygen levels. Under hypoxic conditions, mitochondria can regulate angiogenesis through different factors. It has been indicated that unidirectional and bidirectional exchange of mitochondria or their related byproducts between the cells is orchestrated via different intercellular mechanisms such as tunneling nanotubes, extracellular vesicles, and gap junctions to maintain the cell homeostasis. Even though, the transfer of mitochondria is one possible mechanism by which cells can promote and regulate the process of angiogenesis under reperfusion/ischemia injury. Despite the existence of a close relationship between mitochondrial donation and angiogenic response in different cell types, the precise molecular mechanisms associated with this phenomenon remain unclear. Here, we aimed to highlight the possible role of mitochondria concerning angiogenesis, especially the role of mitochondrial transport and the possible relation of this transfer with autophagy, the housekeeping phenomenon of cells, and angiogenesis.

Two-Dimensional Biodegradable Black Phosphorus Nanosheets Promote Large Full-Thickness Wound Healing through In Situ Regeneration Therapy

Large full-thickness skin lesions have been one of the most challenging clinical problems in plastic surgery repair and reconstruction. To achieve in situ skin regeneration and perfect clinical outcomes, we must address two significant obstacles: angiogenesis deficiency and inflammatory dysfunction. Recently, black phosphorus has shown great promise in wound healing. However, few studies have explored the bio-effects of BP to promote in situ skin regeneration based on its nanoproperties. Here, to investigate whether black phosphorus nanosheets have positive bio-effects on in situ skin repair, we verified black phosphorus nanosheets' positive effects on angiogenic and anti-inflammatory abilities in vitro. Next, the in vivo evaluation performed on the rat large full-thickness excisional wound splinting model more comprehensively showed that the positive bio-effects of black phosphorus nanosheets are multilevel in wound healing, which can effectively enhance anti-inflammatory ability, angiogenesis, collagen deposition, and skin re-epithelialization. Then, multiomics analysis was performed to explore further the mechanism of black phosphorus nanosheets' regulation of endothelial cells in depth. Molecular mechanistically, black phosphorus nanosheets activated the JAK-STAT-OAS signaling pathway to promote cellular function and mitochondrial energy metabolism in endothelial cells. This study can provide a theoretical basis for applying two-dimensional black phosphorus nanosheets as nanomedicine to achieve in situ tissue regeneration in complex human pathological microenvironments, guiding the subsequent optimization of black phosphorus.

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.

Mitochondrial quality control in health and cardiovascular diseases

Cardiovascular diseases (CVDs) are one of the primary causes of mortality worldwide. An optimal mitochondrial function is central to supplying tissues with high energy demand, such as the cardiovascular system. In addition to producing ATP as a power source, mitochondria are also heavily involved in adaptation to environmental stress and fine-tuning tissue functions. Mitochondrial quality control (MQC) through fission, fusion, mitophagy, and biogenesis ensures the clearance of dysfunctional mitochondria and preserves mitochondrial homeostasis in cardiovascular tissues. Furthermore, mitochondria generate reactive oxygen species (ROS), which trigger the production of pro-inflammatory cytokines and regulate cell survival. Mitochondrial dysfunction has been implicated in multiple CVDs, including ischemia-reperfusion (I/R), atherosclerosis, heart failure, cardiac hypertrophy, hypertension, diabetic and genetic cardiomyopathies, and Kawasaki Disease (KD). Thus, MQC is pivotal in promoting cardiovascular health. Here, we outline the mechanisms of MQC and discuss the current literature on mitochondrial adaptation in CVDs.

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.

The hypoxia-inducible factor 1 pathway plays a critical role in the development of breast muscle myopathies in broiler chickens: a comprehensive review

In light of the increased worldwide demand for poultry meat, genetic selection efforts have intensified to produce broiler strains that grow at a higher rate, have greater breast meat yield (BMY), and convert feed to meat more efficiently. The increased selection pressure for these traits, BMY in particular, has produced multiple breast meat quality defects collectively known as breast muscle myopathies (BMM). Hypoxia has been proposed as one of the major mechanisms triggering the onset and occurrence of these myopathies. In this review, the relevant literature on the causes and consequences of hypoxia in broiler breast muscles is reviewed and discussed, with a special focus on the hypoxia-inducible factor 1 (HIF-1) pathway. Muscle fiber hypertrophy induced by selective breeding for greater BMY reduces the space available in the perimysium and endomysium for blood vessels and capillaries. The hypoxic state that results from the lack of circulation in muscle tissue activates the HIF-1 pathway. This pathway alters energy metabolism by promoting anaerobic glycolysis, suppressing the tricarboxylic acid cycle and damaging mitochondrial function. These changes lead to oxidative stress that further exacerbate the progression of BMM. In addition, activating the HIF-1 pathway promotes fatty acid synthesis, lipogenesis, and lipid accumulation in myopathic muscle tissue, and interacts with profibrotic growth factors leading to increased deposition of matrix proteins in muscle tissue. By promoting lipidosis and fibrosis, the HIF-1 pathway contributes to the development of the distinctive phenotypes of BMM, including white striations in white striping-affected muscles and the increased hardness of wooden breast-affected muscles.

Mitochondria in endothelial cells angiogenesis and function: current understanding and future perspectives

Endothelial cells (ECs) angiogenesis is the process of sprouting new vessels from the existing ones, playing critical roles in physiological and pathological processes such as wound healing, placentation, ischemia/reperfusion, cardiovascular diseases and cancer metastasis. Although mitochondria are not the major sites of energy source in ECs, they function as important biosynthetic and signaling hubs to regulate ECs metabolism and adaptations to local environment, thus affecting ECs migration, proliferation and angiogenic process. The understanding of the importance and potential mechanisms of mitochondria in regulating ECs metabolism, function and the process of angiogenesis has developed in the past decades. Thus, in this review, we discuss the current understanding of mitochondrial proteins and signaling molecules in ECs metabolism, function and angiogeneic signaling, to provide new and therapeutic targets for treatment of diverse cardiovascular and angiogenesis-dependent diseases.

Mitochondrial quality control in abdominal aortic aneurysm: From molecular mechanisms to therapeutic strategies

Mitochondria are the energy supply sites of cells and are crucial for eukaryotic life. Mitochondrial dysfunction is involved in the pathogenesis of abdominal aortic aneurysm (AAA). Multiple mitochondrial quality control (MQC) mechanisms, including mitochondrial DNA repair, biogenesis, antioxidant defense, dynamics, and autophagy, play vital roles in maintaining mitochondrial homeostasis under physiological and pathological conditions. Abnormalities in these mechanisms may induce mitochondrial damage and dysfunction leading to cell death and tissue remodeling. Recently, many clues suggest that dysregulation of MQC is closely related to the pathogenesis of AAA. Therefore, specific interventions targeting MQC mechanisms to maintain and restore mitochondrial function have become promising therapeutic methods for the prevention and treatment of AAA.

The mitochondrial protein TIMM44 is required for angiogenesis in vitro and in vivo

The mitochondrial integrity and function in endothelial cells are essential for angiogenesis. TIMM44 (translocase of inner mitochondrial membrane 44) is essential for integrity and function of mitochondria. Here we explored the potential function and the possible mechanisms of TIMM44 in angiogenesis. In HUVECs, human retinal microvascular endothelial cells and hCMEC/D3 brain endothelial cells, silence of TIMM44 by targeted shRNA largely inhibited cell proliferation, migration and in vitro capillary tube formation. TIMM44 silencing disrupted mitochondrial functions in endothelial cells, causing mitochondrial protein input arrest, ATP reduction, ROS production, and mitochondrial depolarization, and leading to apoptosis activation. TIMM44 knockout, by Cas9-sgRNA strategy, also disrupted mitochondrial functions and inhibited endothelial cell proliferation, migration and in vitro capillary tube formation. Moreover, treatment with MB-10 ("MitoBloCK-10"), a TIMM44 blocker, similarly induced mitochondrial dysfunction and suppressed angiogenic activity in endothelial cells. Contrarily, ectopic overexpression of TIMM44 increased ATP contents and augmented endothelial cell proliferation, migration and in vitro capillary tube formation. In adult mouse retinas, endothelial knockdown of TIMM44, by intravitreous injection of endothelial specific TIMM44 shRNA adenovirus, inhibited retinal angiogenesis, causing vascular leakage, acellular capillary growth, and retinal ganglion cells degeneration. Significant oxidative stress was detected in TIMM44-silenced retinal tissues. Moreover, intravitreous injection of MB-10 similarly induced oxidative injury and inhibited retinal angiogenesis in vivo. Together, the mitochondrial protein TIMM44 is important for angiogenesis in vitro and in vivo, representing as a novel and promising therapeutic target of diseases with abnormal angiogenesis.

Mitochondrial disorder and treatment of ischemic cardiomyopathy: Potential and advantages of Chinese herbal medicine

Mitochondrial dysfunction is the main cause of damage to the pathological mechanism of ischemic cardiomyopathy. In addition, mitochondrial dysfunction can also affect the homeostasis of cardiomyocytes or endothelial cell dysfunction, leading to a vicious cycle of mitochondrial oxidative stress. And mitochondrial dysfunction is also an important pathological basis for ischemic cardiomyopathy and reperfusion injury after myocardial infarction or end-stage coronary heart disease. Therefore, mitochondria can be used as therapeutic targets against myocardial ischemia injury, and the regulation of mitochondrial morphology, function and structure is a key and important way of targeting mitochondrial quality control therapeutic mechanisms. Mitochondrial quality control includes mechanisms such as mitophagy, mitochondrial dynamics (mitochondrial fusion/fission), mitochondrial biosynthesis, and mitochondrial unfolded protein responses. Among them, the increase of mitochondrial fragmentation caused by mitochondrial pathological fission is the initial factor. The protective mitochondrial fusion can strengthen the interaction and synthesis of paired mitochondria and promote mitochondrial biosynthesis. In ischemia or hypoxia, pathological mitochondrial fission can promote the formation of mitochondrial fragments, fragmented mitochondria can lead to damaged mitochondrial DNA production, which can lead to mitochondrial biosynthesis dysfunction, insufficient mitochondrial ATP production, and mitochondrial ROS. Burst growth or loss of mitochondrial membrane potential. This eventually leads to the accumulation of damaged mitochondria. Then, under the leadership of mitophagy, damaged mitochondria can complete the mitochondrial degradation process through mitophagy, and transport the morphologically and structurally damaged mitochondria to lysosomes for degradation. But once the pathological mitochondrial fission increases, the damaged mitochondria increases, which may activate the pathway of cardiomyocyte death. Although laboratory studies have found that a variety of mitochondrial-targeted drugs can reduce myocardial ischemia and protect cardiomyocytes, there are still few drugs that have successfully passed clinical trials. In this review, we describe the role of MQS in ischemia/hypoxia-induced cardiomyocyte physiopathology and elucidate the relevant mechanisms of mitochondrial dysfunction in ischemic cardiomyopathy. In addition, we also further explained the advantages of natural products in improving mitochondrial dysfunction and protecting myocardial cells from the perspective of pharmacological mechanism, and explained its related mechanisms. Potential targeted therapies that can be used to improve MQS under ischemia/hypoxia are discussed, aiming to accelerate the development of cardioprotective drugs targeting mitochondrial dysfunction.

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.

Metformin Alleviates Epirubicin-Induced Endothelial Impairment by Restoring Mitochondrial Homeostasis

Vascular endothelial injury is important in anthracycline-induced cardiotoxicity. Anthracyclines seriously damage the mitochondrial function and mitochondrial homeostasis. In this study, we investigated the damage of epirubicin to vascular endothelial cells and the protective role of metformin from the perspective of mitochondrial homeostasis. We found that epirubicin treatment resulted in DNA double-strand breaks (DSB), elevated reactive oxygen species (ROS) production, and excessive Angiotensin II release in HUVEC cells. Pretreatment with metformin significantly mitigated the injuries caused by epirubicin. In addition, inhibited expression of Mitochondrial transcription factor A (TFAM) and increased mitochondria fragmentation were observed in epirubicin-treated cells, which were partially resumed by metformin pretreatment. In epirubicin-treated cells, knockdown of TFAM counteracted the attenuated DSB formation due to metformin pretreatment, and inhibition of mitochondrial fragmentation with Mdivi-1 decreased DSB formation but increased TFAM expression. Furthermore, epirubicin treatment promoted mitochondrial fragmentation by stimulating the expression of Dynamin-1-like protein (DRP1) and inhibiting the expression of Optic atrophy-1(OPA1) and Mitofusin 1(MFN1), which could be partially prevented by metformin. Finally, we found metformin could increase TFAM expression and decrease DRP1 expression in epirubicin-treated HUVEC cells by upregulating the expression of calcineurin/Transcription factor EB (TFEB). Taken together, this study provided evidence that metformin treatment was an effective way to mitigate epirubicin-induced endothelial impairment by maintaining mitochondrial homeostasis.

Prognostic impact of mitofusin 2 expression in colon cancer

BACKGROUND

Mitofusin 2 (MFN2) is involved in several biological processes, including cancer. MFN2 is downregulated in some types of cancer and inhibits cancer cell proliferation, migration, and invasion. However, the relationship between MFN2 and colon cancer remains unknown.

METHODS

In this study, MFN2 expression was investigated using The Cancer Genome Atlas (TCGA) and the Human Protein Atlas (HPA), and the associations between prognostic factors and survival outcomes were assessed via univariate and multivariate analyses. Functional enrichment analyses based on Kyoto Encyclopedia of Genes and Genomes (KEGG) resource and Gene Set Enrichment Analysis (GSEA) were carried out.

RESULTS

MFN2 was downregulated in colon cancer tissues compared with paracancerous colon tissues (P<0.001), and low MFN2 expression was associated with an advanced tumor stage (stage IV vs. stage I, P=0.03; stage I-III vs. stage IV, P=0.003). MFN2 immunohistochemistry (IHC) staining was medium to high in colon normal tissues, but MFN2 IHC staining was faint or not identified in colorectal cancer (CRC) tumor tissues. MFN2 expression was either low or non-existent in colon cancer distinct cell clusters, according to differential gene analysis. Univariate analysis revealed that MFN2 expression in colon cancer patients was significantly associated with the stage [odds ratio (OR) =0.29 for stage IV vs. stage I, P=0.001], T-stage (OR =0.20 for T4 vs. T1, P=0.033), and distant metastasis (OR =0.31 for M1 vs. M0, P=0.000). Furthermore, Kaplan-Meier survival analysis revealed that patients with colon cancer and high MFN2 expression have a better prognosis than those with low MFN2 expression (P=0.002). MFN2 (hazard ratio =0.95, 95% confidence interval: 0.92-0.99, P=0.007) was an independent predictor of colon cancer according to univariate and multivariate Cox models. Finally, GSEA results showed that the KEGG GALACTOSE METABOLISM, APOPTOSIS, and VEGF SIGNALING pathways were activated in the high MFN2 mRNA expression group, whereas the KEGG RIBOSOME pathway was inhibited in the low MFN2 expression group.

CONCLUSIONS

Our research revealed MFN2 to be a promising predictive biomarker and therapeutic target for colon cancer.

Casein Kinase 2 Signaling in White Matter Stroke

The growth of the aging population, together with improved stroke care, has resulted in an increase in stroke survivors and a rise in recurrent events. Axonal injury and white matter (WM) dysfunction are responsible for much of the disability observed after stroke. The mechanisms of WM injury are distinct compared to gray matter and change with age. Therefore, an ideal stroke therapeutic must restore neuronal and axonal function when applied before or after a stroke, and it must also protect across age groups. Casein kinase 2 (CK2), is expressed in the brain, including WM, and is regulated during the development and numerous disease conditions such as cancer and ischemia. CK2 activation in WM mediates ischemic injury by activating the Cdk5 and AKT/GSK3β signaling pathways. Consequently, CK2 inhibition using the small molecule inhibitor CX-4945 (Silmitasertib) correlates with preservation of oligodendrocytes, conservation of axon structure, and axonal mitochondria, leading to improved functional recovery. Remarkably, CK2 inhibition promotes WM function when applied after ischemic injury by specifically regulating the AKT/GSK3β pathways. The blockade of the active conformation of AKT confers post-ischemic protection to young and old WM by preserving mitochondria, implying AKT as a common therapeutic target across age groups. Using a NanoString nCounter miRNA expression profiling, comparative analyses of ischemic WM with or without CX-4945 treatment reveal that miRNAs are expressed at high levels in WM after ischemia, and CX-4945 differentially regulates some of these miRNAs. Therefore, we propose that miRNA regulation may be one of the protective actions of CX-4945 against WM ischemic injury. Silmitasertib is FDA approved and currently in use for cancer and Covid patients; therefore, it is plausible to repurpose CK2 inhibitors for stroke patients.

Mitochondrial and Metabolic Adaptations to Exercise-Induced Fluid Shear Stress in Endothelial Cells

Recent studies have greatly advanced our understanding of the central role of mitochondria on endothelial function. Here, we propose a hypothesis that unidirectional laminar (pulsatile) flow and disturbed laminar (oscillatory) flow may differentially modulate mitochondrial phenotypes in the context of their bioenergetic, signaling, and biosynthetic functions, providing novel insights into subcellular mechanisms underlying how exercise benefits the improvement of vascular health.

Endothelial Autophagy in Coronary Microvascular Dysfunction and Cardiovascular Disease

Coronary microvascular dysfunction (CMD) refers to a subset of structural and/or functional disorders of coronary microcirculation that lead to impaired coronary blood flow and eventually myocardial ischemia. Amid the growing knowledge of the pathophysiological mechanisms and the development of advanced tools for assessment, CMD has emerged as a prevalent cause of a broad spectrum of cardiovascular diseases (CVDs), including obstructive and nonobstructive coronary artery disease, diabetic cardiomyopathy, and heart failure with preserved ejection fraction. Of note, the endothelium exerts vital functions in regulating coronary microvascular and cardiac function. Importantly, insufficient or uncontrolled activation of endothelial autophagy facilitates the pathogenesis of CMD in diverse CVDs. Here, we review the progress in understanding the pathophysiological mechanisms of autophagy in coronary endothelial cells and discuss their potential role in CMD and CVDs.

SIRT3 regulates mitochondrial biogenesis in aging-related diseases

Sirtuin 3 (SIRT3), the main family member of mitochondrial deacetylase, targets the majority of substrates controlling mitochondrial biogenesis via lysine deacetylation and modulates important cellular functions such as energy metabolism, reactive oxygen species production and clearance, oxidative stress, and aging. Deletion of SIRT3 has a deleterious effect on mitochondrial biogenesis, thus leading to the defect in mitochondrial function and insufficient ATP production. Imbalance of mitochondrial dynamics leads to excessive mitochondrial biogenesis, dampening mitochondrial function. Mitochondrial dysfunction plays an important role in several diseases related to aging, such as cardiovascular disease, cancer and neurodegenerative diseases. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) launches mitochondrial biogenesis through activating nuclear respiratory factors. These factors act on genes, transcribing and translating mitochondrial DNA to generate new mitochondria. PGC1α builds a bridge between SIRT3 and mitochondrial biogenesis. This review described the involvement of SIRT3 and mitochondrial dynamics, particularly mitochondrial biogenesis in aging-related diseases, and further illustrated the role of the signaling events between SIRT3 and mitochondrial biogenesis in the pathological process of aging-related diseases.

Natural Herbal Medicine as a Treatment Strategy for Myocardial Infarction through the Regulation of Angiogenesis

Methods

We conducted a literature search on the bioactive components of medicinal plants and their effects on angiogenesis after MI. We searched for articles in Web of Science, MEDLINE, PubMed, Scopus, Google Scholar, and China National Knowledge Infrastructure databases before April 2021.

Results

In this article, we summarized the mechanisms by which copper ions, microRNA, Akt1, inflammation, oxidative stress, mitochondria, and pericytes are involved in angiogenesis after myocardial infarction. In addition, we reviewed the angiogenic effects of natural herbal medicines such as Salvia miltiorrhiza Bunge Bunge, Carthamus tinctorius L., Pueraria lobata, Astragalus, Panax ginseng C.A. Mey., Panax notoginseng (Burkill) F.H. Chen, Cinnamomum cassia (L.) J. Presl, Rehmannia glutinosa (Gaertn.) DC., Leonurus japonicus Houtt, Scutellaria baicalensis Georgi., and Geum macrophyllum Willd.

Conclusions

Some herbs have the effect of promoting angiogenesis. In the future, natural proangiogenic drugs may become candidates for the treatment of cardiovascular diseases.

Advances and Challenges in Biomarkers Use for Coronary Microvascular Dysfunction: From Bench to Clinical Practice

Coronary microvascular dysfunction (CMD) is related to a broad variety of clinical scenarios in which cardiac microvasculature is morphologically and functionally affected, and it is associated with impaired responses to vasoactive stimuli. Although the prevalence of CMD involves about half of all patients with chronic coronary syndromes and more than 20% of those with acute coronary syndrome, the diagnosis of CMD is often missed, leading to the underestimation of its clinical importance. The established and validated techniques for the measurement of coronary microvascular function are invasive and expensive. An ideal method to assess endothelial dysfunction should be accurate, non-invasive, cost-effective and accessible. There are varieties of biomarkers available, potentially involved in microvascular disease, but none have been extensively validated in this heterogeneous clinical population. The investigation of potential biomarkers linked to microvascular dysfunction might improve the assessment of the diagnosis, risk stratification, disease progression and therapy response. This review article offers an update about traditional and novel potential biomarkers linked to CMD.

Biphasic effect of sulforaphane on angiogenesis in hypoxia via modulation of both Nrf2 and mitochondrial dynamics

Sulforaphane (SFN) is an isothiocyanate (ITC) derived from a glucosinolate, glucoraphinin found in cruciferous vegetables. There are few studies that focus on the role of SFN in angiogenesis under hypoxic conditions. The effect of SFN on angiogenesis and the underlying mechanisms including the roles of Nrf2 and mitochondrial dynamics were investigated using cultured human umbilical vein endothelial cells (HUVECs) in hypoxia. SFN at low doses (1.25-5 μM) increased hypoxia-induced HUVEC migration and tube formation, and alleviated hypoxia-induced retarded proliferation, but high doses (≥10 μM) exhibited an opposite effect. Under hypoxia, the expression of Nrf2 and heme oxygenase-1 was up-regulated by SFN treatment. Nrf2 knockdown abrogated SFN (2.5 μM)-induced tube formation and further potentiated the inhibitory effect of SFN (10 μM) on angiogenesis. Meanwhile, the mitochondrial function, morphology and expression of dynamic-related proteins suggested that low-dose SFN protected against hypoxia-induced mitochondrial injury and alleviated hypoxia-induced fission Nrf2-dependently without affecting the expression of key effector proteins (Drp1, Fis1, Mfn1/2 and Opa1), while high concentrations (≥10 μM SFN) aggravated hypoxia-induced mitochondrial injury, fission and Drp1 expression, and inhibited Mfn1/2 expression. These findings suggest that SFN biphasically affected the angiogenic capacity of hypoxia challenged HUVECs potentially via mechanisms involving an integrated modulation of Nrf2 and mitochondrial dynamics.

Mitochondria Lead the Way: Mitochondrial Dynamics and Function in Cellular Movements in Development and Disease

The dynamics, distribution and activity of subcellular organelles are integral to regulating cell shape changes during various physiological processes such as epithelial cell formation, cell migration and morphogenesis. Mitochondria are famously known as the powerhouse of the cell and play an important role in buffering calcium, releasing reactive oxygen species and key metabolites for various activities in a eukaryotic cell. Mitochondrial dynamics and morphology changes regulate these functions and their regulation is, in turn, crucial for various morphogenetic processes. In this review, we evaluate recent literature which highlights the role of mitochondrial morphology and activity during cell shape changes in epithelial cell formation, cell division, cell migration and tissue morphogenesis during organism development and in disease. In general, we find that mitochondrial shape is regulated for their distribution or translocation to the sites of active cell shape dynamics or morphogenesis. Often, key metabolites released locally and molecules buffered by mitochondria play crucial roles in regulating signaling pathways that motivate changes in cell shape, mitochondrial shape and mitochondrial activity. We conclude that mechanistic analysis of interactions between mitochondrial morphology, activity, signaling pathways and cell shape changes across the various cell and animal-based model systems holds the key to deciphering the common principles for this interaction.

Mitochondrial Dynamics: Pathogenesis and Therapeutic Targets of Vascular Diseases

Vascular diseases, particularly atherosclerosis, are associated with high morbidity and mortality. Endothelial cell (EC) or vascular smooth muscle cell (VSMC) dysfunction leads to blood vessel abnormalities, which cause a series of vascular diseases. The mitochondria are the core sites of cell energy metabolism and function in blood vessel development and vascular disease pathogenesis. Mitochondrial dynamics, including fusion and fission, affect a variety of physiological or pathological processes. Multiple studies have confirmed the influence of mitochondrial dynamics on vascular diseases. This review discusses the regulatory mechanisms of mitochondrial dynamics, the key proteins that mediate mitochondrial fusion and fission, and their potential effects on ECs and VSMCs. We demonstrated the possibility of mitochondrial dynamics as a potential target for the treatment of vascular diseases.

Exercise improves vascular health: Role of mitochondria

Vascular mitochondria constantly integrate signals from environment and respond accordingly to match vascular function to metabolic requirements of the organ tissues, while mitochondrial dysfunction contributes to vascular aging and pathologies such as atherosclerosis, stenosis, and hypertension. As an effective lifestyle intervention, exercise induces extensive mitochondrial adaptations through vascular mechanical stress and the increased production and release of reactive oxygen species and nitric oxide that activate multiple intracellular signaling pathways, among which peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) plays a critical role. PGC-1α coordinates mitochondrial quality control mechanisms to maintain a healthy mitochondrial pool and promote endothelial nitric oxide synthase activity in vasculature. The mitochondrial adaptations to exercise improve bioenergetics, balance redox status, protect endothelial cells against detrimental insults, increase vascular plasticity, and ameliorate aging-related vascular dysfunction, thus benefiting vascular health. This review highlights recent findings of mitochondria as a central hub integrating exercise-afforded vascular benefits and its underlying mechanisms. A better understanding of the mitochondrial adaptations to exercise will not only shed light on the mechanisms of exercise-induced cardiovascular protection, but may also provide new clues to mitochondria-oriented precise exercise prescriptions for cardiovascular health.

Potential of natural products in osteosarcoma treatment: Focus on molecular mechanisms

Osteosarcoma is the most frequent type of bone cancer found in children and adolescents, and commonly arises in the metaphyseal region of tubular long bones. Standard therapeutic approaches, such as surgery, chemotherapy, and radiation therapy, are used in the management of osteosarcoma. In recent years, the mortality rate of osteosarcoma has decreased due to advances in treatment methods. Today, the scientific community is investigating the use of different naturally derived active principles against various types of cancer. Natural bioactive compounds can function against cancer cells in two ways. Firstly they can act as classical cytotoxic compounds by non-specifically affecting macromolecules, such as DNA, enzymes, and microtubules, which are also expressed in normal proliferating cells, but to a greater extent by cancer cells. Secondly, they can act against oncogenic signal transduction pathways, many of which are activated in cancer cells. Some bioactive plant-derived agents are gaining increasing attention because of their anti-cancer properties. Moreover, some naturally-derived compounds can significantly promote the effectiveness of standard chemotherapy drugs, and in certain cases are able to ameliorate drug-induced adverse effects caused by chemotherapy. In the present review we summarize the effects of various naturally-occurring bioactive compounds against osteosarcoma.

Interplay Between Reactive Oxygen/Reactive Nitrogen Species and Metabolism in Vascular Biology and Disease

Reactive oxygen species (ROS; e.g., superoxide [O₂^•-] and hydrogen peroxide [H₂O₂]) and reactive nitrogen species (RNS; e.g., nitric oxide [NO^•]) at the physiological level function as signaling molecules that mediate many biological responses, including cell proliferation, migration, differentiation, and gene expression. By contrast, excess ROS/RNS, a consequence of dysregulated redox homeostasis, is a hallmark of cardiovascular disease. Accumulating evidence suggests that both ROS and RNS regulate various metabolic pathways and enzymes. Recent studies indicate that cells have mechanisms that fine-tune ROS/RNS levels by tight regulation of metabolic pathways, such as glycolysis and oxidative phosphorylation. The ROS/RNS-mediated inhibition of glycolytic pathways promotes metabolic reprogramming away from glycolytic flux toward the oxidative pentose phosphate pathway to generate nicotinamide adenine dinucleotide phosphate (NADPH) for antioxidant defense. This review summarizes our current knowledge of the mechanisms by which ROS/RNS regulate metabolic enzymes and cellular metabolism and how cellular metabolism influences redox homeostasis and the pathogenesis of disease. A full understanding of these mechanisms will be important for the development of new therapeutic strategies to treat diseases associated with dysregulated redox homeostasis and metabolism. Antioxid. Redox Signal. 34, 1319-1354.

FUNDC1-dependent mitochondria-associated endoplasmic reticulum membranes are involved in angiogenesis and neoangiogenesis

FUN14 domain-containing protein 1 (FUNDC1) is an integral mitochondrial outer-membrane protein, and mediates the formation of mitochondria-associated endoplasmic reticulum membranes (MAMs). This study aims to determine the contributions of FUNDC1-mediated MAMs to angiogenesis in vitro and in vivo. In cultured endothelial cells, VEGF significantly increases the formation of MAMs and MAM-related proteins, including FUNDC1. Endothelial cell-specific deletion of FUNDC1, which disrupts MAM formation in endothelial cells, lowers VEGFR2 expression and reduces tube formation, spheroid-sprouting, and functional blood vessel formation in vitro and in vivo. Conversely, increased MAM formation using MAM linkers mimics the effects of VEGF and promotes endothelial angiogenesis. Mechanistically, increased MAMs formation led to increased levels of Ca2+ in cytosol, promoted the phosphorylation of serum response factor (SRF) and enhanced the binding of SRF to VEGFR2 promoter, resulting in increased VEGFR2 production, with consequent angiogenesis. Moreover, blocking FUNDC1-related MAM formation with a cell-penetrating inhibitory peptide significantly suppresses the expressions of downstream angiogenic genes and inhibits tumor angiogenesis. We conclude that decreased MAMs formation by silencing FUNDC1 can inhibit angiogenesis by decreasing VEGFR2 expression, and targeting FUNDC1-dependent MAMs might be a promising approach for treating human disorders characterized by defective angiogenesis.

Coronary microvascular injury in myocardial infarction: perception and knowledge for mitochondrial quality control

Endothelial cells (ECs) constitute the innermost layer in all blood vessels to maintain the structural integrity and microcirculation function for coronary microvasculature. Impaired endothelial function is demonstrated in various cardiovascular diseases including myocardial infarction (MI), which is featured by reduced myocardial blood flow as a result of epicardial coronary obstruction, thrombogenesis, and inflammation. In this context, understanding the cellular and molecular mechanisms governing the function of coronary ECs is essential for the early diagnosis and optimal treatment of MI. Although ECs contain relatively fewer mitochondria compared with cardiomyocytes, they function as key sensors of environmental and cellular stress, in the regulation of EC viability, structural integrity and function. Mitochondrial quality control (MQC) machineries respond to a broad array of stress stimuli to regulate fission, fusion, mitophagy and biogenesis in mitochondria. Impaired MQC is a cardinal feature of EC injury and dysfunction. Hence, medications modulating MQC mechanisms are considered as promising novel therapeutic options in MI. Here in this review, we provide updated insights into the key role of MQC mechanisms in coronary ECs and microvascular dysfunction in MI. We also discussed the option of MQC as a novel therapeutic target to delay, reverse or repair coronary microvascular damage in MI. Contemporary available MQC-targeted therapies with potential clinical benefits to alleviate coronary microvascular injury during MI are also summarized.

Drp1-dependent mitochondrial fission in cardiovascular disease

Mitochondria are highly dynamic organelles undergoing cycles of fusion and fission to modulate their morphology, distribution, and function, which are referred as 'mitochondrial dynamics'. Dynamin-related protein 1 (Drp1) is known as the major pro-fission protein whose activity is tightly regulated to clear the damaged mitochondria via mitophagy, ensuring a strict control over the intricate process of cellular and organ dynamics in heart. Various posttranslational modifications (PTMs) of Drp1 have been identified including phosphorylation, SUMOylation, palmitoylation, ubiquitination, S-nitrosylation, and O-GlcNAcylation, which implicate a role in the regulation of mitochondrial dynamics. An intact mitochondrial homeostasis is critical for heart to fuel contractile function and cardiomyocyte metabolism, while defects in mitochondrial dynamics constitute an essential part of the pathophysiology underlying various cardiovascular diseases (CVDs). In this review, we summarize current knowledge on the critical role of Drp1 in the pathogenesis of CVDs including endothelial dysfunction, smooth muscle remodeling, cardiac hypertrophy, pulmonary arterial hypertension, myocardial ischemia-reperfusion, and myocardial infarction. We also highlight how the targeting of Drp1 could potentially contribute to CVDs treatments.

The ER-mitochondria Ca2+ signaling in cancer progression: Fueling the monster

Cancer is a leading cause of death worldwide. All major tumor suppressors and oncogenes are now recognized to have fundamental connections with metabolic pathways. A hallmark feature of cancer cells is a reprogramming of their metabolism even when nutrients are available. Increasing evidence indicates that most cancer cells rely on mitochondrial metabolism to sustain their energetic and biosynthetic demands. Mitochondria are functionally and physically coupled to the endoplasmic reticulum (ER), the major calcium (Ca²⁺) storage organelle in mammalian cells, through special domains known as mitochondria-ER contact sites (MERCS). In this domain, the release of Ca²⁺ from the ER is mainly regulated by inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs), a family of Ca²⁺ release channels activated by the ligand IP3. IP3R mediated Ca²⁺ release is transferred to mitochondria through the mitochondrial Ca²⁺ uniporter (MCU). Once in the mitochondrial matrix, Ca²⁺ activates several proteins that stimulate mitochondrial performance. The role of IP3R and MCU in cancer, as well as the other proteins that enable the Ca²⁺ communication between these two organelles is just beginning to be understood. Here, we describe the function of the main players of the ER mitochondrial Ca²⁺ communication and discuss how this particular signal may contribute to the rise and development of cancer traits.

Mitofusin-2 is a novel anti-angiogenic factor in pancreatic cancer

Background

Aberrant expression of mitofusin-2 (MFN2) has been found to be associated with vascular endothelial growth factor A (VEGFA)-mediated angiogenesis in human umbilical vein endothelial cells (HUVECs). This study aimed to investigate the expression of MFN2 in pancreatic cancer (PC) and the role of MFN2 in vascular endothelial cell growth and angiogenesis.

Methods

Protein and mRNA expression of MFN2 and VEGFA were measured. The CCK-8 assay, tube formation assay, flow cytometry, and transmission electron microscopy were used to examine the effects of MFN2 overexpression on HUVEC growth, angiogenesis, and apoptosis. Western blot and immunocytochemical staining were conducted to measure alterations in cell cycle and apoptosis regulators and vascular endothelial growth factor receptor 2 (VEGFR2), angiopoietin-1 gene (ANGPT1), and tissue inhibitor of metalloproteinase 1 (TIMP1) expression in HUVECs.

Results

The results showed that MFN2 levels were significantly decreased in tumor tissues. Contrasting results were observed for VEGFA mRNA levels. MFN2 overexpression inhibited cell growth while promoting the formation of apoptotic bodies in HUVECs. Additionally, MFN2 overexpression enhanced the protein expression of p21 and p27 while attenuating the expression of proliferating cell nuclear antigen, VEGFA, VEGFR2, ANGPT1, and TIPM1 in HUVECs.

Conclusions

In conclusion, MFN2 expression negatively correlates with VEGFA expression in PC and inhibits endothelial cell growth and angiogenesis.

Quality Matters? The Involvement of Mitochondrial Quality Control in Cardiovascular Disease

Cardiovascular diseases are one of the leading causes of death and global health problems worldwide. Multiple factors are known to affect the cardiovascular system from lifestyles, genes, underlying comorbidities, and age. Requiring high workload, metabolism of the heart is largely dependent on continuous power supply via mitochondria through effective oxidative respiration. Mitochondria not only serve as cellular power plants, but are also involved in many critical cellular processes, including the generation of intracellular reactive oxygen species (ROS) and regulating cellular survival. To cope with environmental stress, mitochondrial function has been suggested to be essential during bioenergetics adaptation resulting in cardiac pathological remodeling. Thus, mitochondrial dysfunction has been advocated in various aspects of cardiovascular pathology including the response to ischemia/reperfusion (I/R) injury, hypertension (HTN), and cardiovascular complications related to type 2 diabetes mellitus (DM). Therefore, mitochondrial homeostasis through mitochondrial dynamics and quality control is pivotal in the maintenance of cardiac health. Impairment of the segregation of damaged components and degradation of unhealthy mitochondria through autophagic mechanisms may play a crucial role in the pathogenesis of various cardiac disorders. This article provides in-depth understanding of the current literature regarding mitochondrial remodeling and dynamics in cardiovascular diseases.

The lncRNA Malat1 regulates microvascular function after myocardial infarction in mice via miR-26b-5p/Mfn1 axis-mediated mitochondrial dynamics

RATIONALE

Myocardial infarction (MI) is a leading cause of cardiovascular mortality globally. The improvement of microvascular function is critical for cardiac repair after MI. Evidence now points to long non-coding RNAs (lncRNAs) as key regulators of cardiac remodelling processes. The lncRNA Malat1 is involved in the development and progression of multiple cardiac diseases. Studies have shown that Malat1 is closely related to the regulation of endothelial cell regeneration. However, the potential molecular mechanisms of Malat1 in repairing cardiac microvascular dysfunction after MI remain unreported.

METHODS AND RESULTS

The present study found that Malat1 is upregulated in the border zone of infarction in mouse hearts, as well as in isolated cardiac microvascular endothelial cells (CMECs). Targeted knockdown of Malat1 in endothelial cells exacerbated oxidative stress, attenuated angiogenesis and microvascular perfusion, and as a result decreased cardiac function in MI mice. Further studies showed that silencing Malat1 obviously inhibited CMEC proliferation, migration and tube formation, which was at least in part attributed to disturbed mitochondrial dynamics and activation of the mitochondrial apoptosis pathway. Moreover, bioinformatic analyses, luciferase assays and pull-down assays indicated that Malat1 acted as a competing endogenous RNA (ceRNA) for miR-26b-5p and formed a signalling axis with Mfn1 to regulate mitochondrial dynamics and endothelial functions. Overexpression of Mfn1 markedly reversed the microvascular dysfunction and CMEC injuries that were aggravated by silencing Malat1 via inhibition of excessive mitochondrial fragments and mitochondria-dependent apoptosis.

CONCLUSIONS

The present study elucidated the functions and mechanisms of Malat1 in cardiac microcirculation repair after MI. The underlying mechanisms of the effects of Malat1 could be attributed to its blocking effects on miR-26b-5p/Mfn1 pathway-mediated mitochondrial dynamics and apoptosis.

ATPIF1 maintains normal mitochondrial structure which is impaired by CCM3 deficiency in endothelial cells

Background

Numerous signaling pathways have been demonstrated experimentally to affect the pathogenesis of cerebral cavernous malformations (CCM), a disease that can be caused by CCM3 deficiency. However, the understanding of the CCM progression is still limited. The objective of the present work was to elucidate the role of CCM3 by RNA-seq screening of CCM3 knockout mice.

Results

We found that ATPIF1 was decreased in siCCM3-treated Human Umbilical Vein Endothelial Cells (HUVECs), and the overexpression of ATPIF1 attenuated the changes in cell proliferation, adhesion and migration caused by siCCM3. The probable mechanism involved the conserved ATP concentration in mitochondria and the elongated morphology of the organelles. By using the CRISPR-cas9 system, we generated CCM3-KO Endothelial Progenitor Cells (EPCs) and found that the knockout of CCM3 destroyed the morphology of mitochondria, impaired the mitochondrial membrane potential and increased mitophagy. Overexpression of ATPIF1 contributed to the maintenance of normal structure of mitochondria, inhibiting activation of mitophagy and other signaling proteins (e.g., KLF4 and Tie2). The expression of KLF4 returned to normal in CCM3-KO EPCs after 2 days of re-overexpression of CCM3, but not other signaling proteins.

Conclusion

ATPIF1 maintains the normal structure of mitochondria, inhibiting the activation of mitophagy and other signaling pathway in endothelial cells. Loss of CCM3 leads to the destruction of mitochondria and activation of signaling pathways, which can be regulated by KLF4.

Can Metformin Exert as an Active Drug on Endothelial Dysfunction in Diabetic Subjects?

Cardiovascular mortality is a major cause of death among in type 2 diabetes (T2DM). Endothelial dysfunction (ED) is a well-known important risk factor for the development of diabetes cardiovascular complications. Therefore, the prevention of diabetic macroangiopathies by preserving endothelial function represents a major therapeutic concern for all National Health Systems. Several complex mechanisms support ED in diabetic patients, frequently cross-talking each other: uncoupling of eNOS with impaired endothelium-dependent vascular response, increased ROS production, mitochondrial dysfunction, activation of polyol pathway, generation of advanced glycation end-products (AGEs), activation of protein kinase C (PKC), endothelial inflammation, endothelial apoptosis and senescence, and dysregulation of microRNAs (miRNAs). Metformin is a milestone in T2DM treatment. To date, according to most recent EASD/ADA guidelines, it still represents the first-choice drug in these patients. Intriguingly, several extraglycemic effects of metformin have been recently observed, among which large preclinical and clinical evidence support metformin’s efficacy against ED in T2DM. Metformin seems effective thanks to its favorable action on all the aforementioned pathophysiological ED mechanisms. AMPK pharmacological activation plays a key role, with metformin inhibiting inflammation and improving ED. Therefore, aim of this review is to assess metformin’s beneficial effects on endothelial dysfunction in T2DM, which could preempt development of atherosclerosis.

Mitofusin 2 regulates neutrophil adhesive migration and the actin cytoskeleton

Neutrophils rely on glycolysis for energy production. How mitochondria regulate neutrophil function is not fully understood. Here, we report that mitochondrial outer membrane protein Mitofusin 2 (MFN2) regulates neutrophil homeostasis and chemotaxis in vivoMfn2-deficient neutrophils are released from the hematopoietic tissue, trapped in the vasculature in zebrafish embryos, and not capable of chemotaxis. Consistent with this, human neutrophil-like cells that are deficient for MFN2 fail to arrest on activated endothelium under sheer stress or perform chemotaxis on 2D surfaces. Deletion of MFN2 results in a significant reduction of neutrophil infiltration to the inflamed peritoneal cavity in mice. Mechanistically, MFN2-deficient neutrophil-like cells display disrupted mitochondria-ER interaction, heightened intracellular Ca2+ levels and elevated Rac activation after chemokine stimulation. Restoring a mitochondria-ER tether rescues the abnormal Ca2+ levels, Rac hyperactivation and chemotaxis defect resulting from MFN2 depletion. Finally, inhibition of Rac activation restores chemotaxis in MFN2-deficient neutrophils. Taken together, we have identified that MFN2 regulates neutrophil migration via maintaining the mitochondria-ER interaction to suppress Rac activation, and uncovered a previously unrecognized role of MFN2 in regulating cell migration and the actin cytoskeleton.This article has an associated First Person interview with the first authors of the paper.

Vascular autophagy in health and disease

Homeostasis is maintained within organisms through the physiological recycling process of autophagy, a catabolic process that is intricately involved in the mobilization of nutrients during starvation, recycling of cellular cargo, as well as initiation of cellular death pathways. Specific to the cardiovascular system, autophagy responds to both chemical (e.g. free radicals) and mechanical stressors (e.g. shear stress). It is imperative to note that autophagy is not a static process, and measurement of autophagic flux provides a more comprehensive investigation into the role of autophagy. The overarching themes emerging from decades of autophagy research are that basal levels of autophagic flux are critical, physiological stressors may increase or decrease autophagic flux, and more importantly, aberrant deviations from basal autophagy may elicit detrimental effects. Autophagy has predominantly been examined within cardiac or vascular smooth muscle tissue within the context of disease development and progression. Autophagic flux within the endothelium holds an important role in maintaining vascular function, demonstrated by the necessary role for intact autophagic flux for shear-induced release of nitric oxide however the underlying mechanisms have yet to be elucidated. Within this review, we theorize that autophagy itself does not solely control vascular homeostasis, rather, it works in concert with mitochondria, telomerase, and lipids to maintain physiological function. The primary emphasis of this review is on the role of autophagy within the human vasculature, and the integrative effects with physiological processes and diseases as they relate to the vascular structure and function.

Pharmacological management of vascular endothelial dysfunction in diabetes: TCM and western medicine compared based on biomarkers and biochemical parameters

Diabetes, a worldwide health concern while burdening significant populace of countries with time due to a hefty increase in both incidence and prevalence rates. Hyperglycemia has been buttressed both in clinical and experimental studies to modulate widespread molecular actions that effect macro and microvascular dysfunctions. Endothelial dysfunction, activation, inflammation, and endothelial barrier leakage are key factors contributing to vascular complications in diabetes, plus the development of diabetes-induced cardiovascular diseases. The recent increase in molecular, transcriptional, and clinical studies has brought a new scope to the understanding of molecular mechanisms and the therapeutic targets for endothelial dysfunction in diabetes. In this review, an attempt made to discuss up to date critical and emerging molecular signaling pathways involved in the pathophysiology of endothelial dysfunction and viable pharmacological management targets. Importantly, we exploit some Traditional Chinese Medicines (TCM)/TCM isolated bioactive compounds modulating effects on endothelial dysfunction in diabetes. Finally, clinical studies data on biomarkers and biochemical parameters involved in the assessment of the efficacy of treatment in vascular endothelial dysfunction in diabetes was compared between clinically used western hypoglycemic drugs and TCM formulas.

Developmental and Tumor Angiogenesis Requires the Mitochondria-Shaping Protein Opa1

While endothelial cell (EC) function is influenced by mitochondrial metabolism, the role of mitochondrial dynamics in angiogenesis, the formation of new blood vessels from existing vasculature, is unknown. Here we show that the inner mitochondrial membrane mitochondrial fusion protein optic atrophy 1 (OPA1) is required for angiogenesis. In response to angiogenic stimuli, OPA1 levels rapidly increase to limit nuclear factor kappa-light-chain-enhancer of activated B cell (NFκB) signaling, ultimately allowing angiogenic genes expression and angiogenesis. Endothelial Opa1 is indeed required in an NFκB-dependent pathway essential for developmental and tumor angiogenesis, impacting tumor growth and metastatization. A first-in-class small molecule-specific OPA1 inhibitor confirms that EC Opa1 can be pharmacologically targeted to curtail tumor growth. Our data identify Opa1 as a crucial component of physiological and tumor angiogenesis.

OPA1 and Angiogenesis: Beyond the Fusion Function

In this issue of Cell Metabolism, Herkenne et al. (2020) show that the mitochondrial fusion protein OPA1 promotes angiogenesis independent of its function in mitochondrial dynamics, identifying a key new therapeutic target to prevent vascular growth during development and tumor formation.

New insights into the role of mitochondria in cardiac microvascular ischemia/reperfusion injury

As reperfusion therapies have become more widely used in acute myocardial infarction patients, ischemia-induced myocardial damage has been markedly reduced, but reperfusion-induced cardiac injury has become increasingly evident. The features of cardiac ischemia-reperfusion (I/R) injury include microvascular perfusion defects, platelet activation and sequential cardiomyocyte death due to additional ischemic events at the reperfusion stage. Microvascular obstruction, defined as a no-reflow phenomenon, determines the infarct zone, myocardial function and peri-operative mortality. Cardiac microvascular endothelial cell injury may occur much earlier and with much greater severity than cardiomyocyte injury. Endothelial cells contain fewer mitochondria than other cardiac cells, and several of the pathological alterations during cardiac microvascular I/R injury involve mitochondria, such as increased mitochondrial reactive oxygen species (mROS) levels and disturbed mitochondrial dynamics. Although mROS are necessary physiological second messengers, high mROS levels induce oxidative stress, endothelial senescence and apoptosis. Mitochondrial dynamics, including fission, fusion and mitophagy, determine the shape, distribution, size and function of mitochondria. These adaptive responses modify extracellular signals and orchestrate intracellular processes such as cell proliferation, migration, metabolism, angiogenesis, permeability transition, adhesive molecule expression, endothelial barrier function and anticoagulation. In this review, we discuss the involvement of mROS and mitochondrial morphofunction in cardiac microvascular I/R injury.

Pulmonary Hypertension Remodels the Genomic Fabrics of Major Functional Pathways

Pulmonary hypertension (PH) is a serious disorder with high morbidity and mortality rate. We analyzed the right-ventricular systolic pressure (RVSP), right-ventricular hypertrophy (RVH), lung histology, and transcriptomes of six-week-old male rats with PH induced by (1) hypoxia (HO), (2) administration of monocrotaline (CM), or (3) administration of monocrotaline and exposure to hypoxia (HM). The results in PH rats were compared to those in control rats (CO). After four weeks exposure, increased RVSP and RVH, pulmonary arterial wall thickening, and alteration of the lung transcriptome were observed in all PH groups. The HM group exhibited the largest alterations, as well as neointimal lesions and obliteration of the lumen in small arteries. We found that PH increased the expression of caveolin1, matrix metallopeptidase 2, and numerous inflammatory and cell proliferation genes. The cell cycle, vascular smooth muscle contraction, and oxidative phosphorylation pathways, as well as their interplay, were largely perturbed. Our results also suggest that the upregulated Rhoa (Ras homolog family member A) mediates its action through expression coordination with several ATPases. The upregulation of antioxidant genes and the extensive mitochondrial damage observed, especially in the HM group, indicate metabolic shift toward aerobic glycolysis.

A-kinase anchoring protein 1 (AKAP1) and its role in some cardiovascular diseases

A-kinase anchoring proteins (AKAPs) play crucial roles in regulating compartmentalized multi-protein signaling networks related to PKA-mediated phosphorylation. The mitochondrial AKAP - AKAP1 proteins are enriched in heart and play cardiac protective roles. This review aims to thoroughly summarize AKAP1 variants from their sequence features to the structure-function relationships between AKAP1 and its binding partners, as well as the molecular mechanisms of AKAP1 in cardiac hypertrophy, hypoxia-induced myocardial infarction and endothelial cells dysfunction, suggesting AKAP1 as a candidate for cardiovascular therapy.

Silibinin inhibits migration and invasion of breast cancer MDA-MB-231 cells through induction of mitochondrial fusion

Human triple negative breast cancer cells, MDA-MB-231, show typical epithelial to mesenchymal transition associated with cancer progression. Mitochondria play a major role in cancer progression, including metastasis. Changes in mitochondrial architecture affect cellular migration, autophagy and apoptosis. Silibinin is reported to have anti-breast cancer effect. We here report that silibinin at lower concentrations (30-90 μM) inhibits epithelial to mesenchymal transition (EMT) of MDA-MB-231, by increasing the expression of epithelial marker, E-cadherin, and decreasing the expression of mesenchymal markers, N-cadherin and vimentin. Besides, silibinin inhibition of cell migration is associated with reduction in the protein expression of matrix metalloproteinases 2 and 9 (MMP2 and MMP9) and paxillin. In addition, silibinin treatment increases mitochondrial fusion through down-regulating the expression of mitochondrial fission-associated protein dynamin-related protein 1 (DRP1) and up-regulating the expression of mitochondrial fusion-associated proteins, optic atrophy 1, mitofusin 1 and mitofusin 2. Silibinin perturbed mitochondrial biogenesis via down-regulating the levels of mitochondrial biogenesis regulators including mitochondrial transcription factor A (TFAM), peroxisome proliferator-activated receptor gamma coactivator (PGC1) and nuclear respiratory factor (NRF2). Moreover, DRP1 knockdown or silibinin inhibited cell migration, and MFN1&2 knockdown restored it. Mitochondrial fusion contributes to silibinin's negative effect on cell migration. Silibinin decreased reactive oxygen species (ROS) generation, leading to inhibition of the NLRP3 inflammasome activation. In addition, knockdown of mitofusin 1&2 (MFN 1&2) relieved silibinin-induced inhibition of NLRP3 inflammasome activation. Repression of ROS contributes to the inhibition of the expression of NLRP3, caspase-1 and IL-β proteins as well as of cell migration. Taken together, our study provides evidence that silibinin impairs mitochondrial dynamics and biogenesis, resulting in reduced migration and invasion of the MDA-MB-231 breast cancer cells.

Maternal serum mitofusin-2 levels in patients with preeclampsia: the possible role of mitochondrial dysfunction in preeclampsia

Purpose: Hypoxia alters mitochondria function and our aim was to measure mitochondrial fusion protein mitofusin-2 (Mfn2) in patients with preeclampsia.Materials and methods: This cross-sectional study was conducted including 82 pregnant women, 27 with normal pregnancy and 55 with preeclampsia (27 with early-onset preeclampsia and 28 with late-onset preeclampsia). Maternal serum levels of Mfn2 were measured by using enzyme-linked immunosorbent assay kits.Results: The mean serum mitofusin-2 levels were higher in women with preeclampsia than in the control group (68.02 ± 8.7 pg/mL vs. 99.72 ± 37.27 pg/mL, p < .0001). The mean serum mitofusin-2 level was found to be the highest in the early-onset preeclampsia (EOPE) group (EOPE: 101.6 ± 38.5 pg/mL). Maternal serum mitofusin-2 levels correlated with both systolic and diastolic blood pressures as well as uterine artery pulsatility index. The optimal cutoff value of Mfn2 for determining preeclampsia was 75.3 pg/mL.Conclusion: Mfn2 has regulatory roles in stress response. Maternal serum Mfn2 is higher in patients with preeclampsia suggesting that Mfn2 increases in the maternal system as a stress response against hypoxia and endothelial dysfunction.What do the results of this study add? Hypoxia causes mitochondrial dysfunction that has been linked to the etiology of many diseases including preeclampsia. Mitofusin-2 is a mitochondrial fusion protein, and the levels can be altered in preeclampsia. For the first time, we showed that maternal levels of mitofusin-2 are higher in patients with preeclampsia. Further, we reported the correlation of mitofusin-2 with blood pressures and uterine artery pulsatility index. These findings will open up other avenues for researchers to investigate other mitochondrial molecules while under stress.