Glucose withdrawal induces Endothelin 1 release with significant angiogenic effect from first trimester (FTM), but not term human umbilical cord perivascular cells (HUCPVC)

Hypoxia and low-glucose environments co-induced HGDILnc1 promote glycolysis and angiogenesis

Small bowel vascular malformation disease (SBVM) commonly causes obscure gastrointestinal bleeding (OGIB). However, the pathogenetic mechanism and the role of lncRNAs in SBVM remain largely unknown. Here, we found that hypoxia and low-glucose environments co-augment angiogenesis and existed in SBVM. Mechanistically, hypoxia and low-glucose environments supported angiogenesis via activation of hypoxia and glucose deprivation-induced lncRNA (HGDILnc1) transcription by increasing binding of the NeuroD1 transcription factor to the HGDILnc1 promoter. Raised HGDILnc1 acted as a suppressor of α-Enolase 1 (ENO1) small ubiquitin-like modifier modification (SUMOylation)-triggered ubiquitination, and an activator of transcription of Aldolase C (ALDOC) via upregulation of Histone H2B lysine 16 acetylation (H2BK16ac) level in the promoter of ALDOC, and consequently promoting glycolysis and angiogenesis. Moreover, HGDILnc1 was clinically positively correlated with Neurogenic differentiation 1 (NeuroD1), ENO1, and ALDOC in SBVM tissues, and could function as a biomarker for SBVM diagnosis and therapy. These findings suggest that hypoxia and low-glucose environments were present in SBVM tissues, and co-augmented angiogenesis. Hypoxia and low-glucose environments co-induced HGDILnc1, which is higher expressed in SBVM tissue compared with normal tissue, could promoted glycolysis and angiogenesis.

Synergistic effect of FGF-2 and TGF-β1 on the mineralization of human umbilical cord perivascular cells

OBJECTIVE

Human umbilical cord perivascular cells (HUCPVCs) are derived from the human umbilical cord perivascular tissue and are expected to replace mesenchymal stromal cells in the future. We investigated the synergistic effects of fibroblast growth factor 2 (FGF-2) and transforming growth factor-beta 1 (TGF-β1) on HUCPVC mineralization.

DESIGN

We prepared HUCPVCs with (FGF(+)HUCPVCs) or without FGF-2 (FGF(-)HUCPVCs) in the presence of activated vitamin D3, a bone morphogenic protein inhibitor, and TGF-β1. We examined the cell proliferative capacity, expression of various hard tissue-forming cell gene markers, and mineralization induction ability and identified the crystalline phases of the mineralized nodules.

RESULTS

FGF(+)HUCPVCs exhibited higher intracellular alkaline phosphatase (ALP) gene expression and ALP activity, and their cell proliferation rate was higher than that of FGF(-)HUCPVCs. The expression levels of osteoblast marker genes increased in FGF(+)HUCPVCs, whereas those of elastic fiber and muscle cell markers increased in FGF(-)HUCPVCs. The expression of genes related to matrix vesicle-mediated mineralization was increased in FGF(+)HUCPVCs. While FGF(-)HUCPVCs displayed myofibroblast-like properties and could not induce mineralization, FGF(+)HUCPVCs demonstrated the ability to produce mineralized nodules. The resulting mineralized nodules consisted of hydroxyapatite as the major phase and minor amounts of octacalcium phosphate. The mineralized nodules exhibited the morphological characteristics of bone hydroxyapatite, composed of fibrous hydroxyapatite nanorods and polycrystalline sheets.

CONCLUSION

We found that FGF-2 synergizes with TGF-β1 and is a key factor in the differentiation of HUCPVCs into osteoblast-like cells. Thus, HUCPVCs can potentially serve as a new stem cell source for future bone regeneration and dental treatments.

Hypoxia and panvascular diseases: exploring the role of hypoxia-inducible factors in vascular smooth muscle cells under panvascular pathologies

As an emerging discipline, panvascular diseases are a set of vascular diseases with atherosclerosis as the common pathogenic hallmark, which mostly affect vital organs like the heart, brain, kidney, and limbs. As the major responser to the most common stressor in the vasculature (hypoxia)-hypoxia-inducible factors (HIFs), and the primary regulator of pressure and oxygen delivery in the vasculature-vascular smooth muscle cells (VSMCs), their own multifaceted nature and their interactions with each other are fascinating. Abnormally active VSMCs (e.g., atherosclerosis, pulmonary hypertension) or abnormally dysfunctional VSMCs (e.g., aneurysms, vascular calcification) are associated with HIFs. These widespread systemic diseases also reflect the interdisciplinary nature of panvascular medicine. Moreover, given the comparable proliferative characteristics exhibited by VSMCs and cancer cells, and the delicate equilibrium between angiogenesis and cancer progression, there is a pressing need for more accurate modulation targets or combination approaches to bolster the effectiveness of HIF targeting therapies. Based on the aforementioned content, this review primarily focused on the significance of integrating the overall and local perspectives, as well as temporal and spatial balance, in the context of the HIF signaling pathway in VSMC-related panvascular diseases. Furthermore, the review discussed the implications of HIF-targeting drugs on panvascular disorders, while considering the trade-offs involved.

Time course and mechanistic analysis of human umbilical cord perivascular cell mitigation of lipopolysaccharide-induced systemic and neurological inflammation

BACKGROUND AIMS

Because of their potent immunomodulatory and anti-inflammatory properties, mesenchymal stromal cells are a major focus in the field of stem cell therapy. However, the precise mechanisms underlying this are not entirely understood. Human umbilical cord perivascular cells (HUCPVCs) are a promising cell therapy candidate. This study was designed to evaluate the time course and mechanisms by which HUCPVCs mitigate lipopolysaccharide (LPS)-induced systemic and neurological inflammation in immunocompetent mice. To explore the underlying mechanisms, the authors investigated the biodistribution and fate of HUCPVCs.

METHODS

Male C57BL/6 mice were randomly allocated to four groups: control, LPS, HUCPVCs or LPS + HUCPVCs. Quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and cytokine arrays were used to assess changes in pro-inflammatory mediators systemically and in the brain. Depressive-like behavioral changes were evaluated via a forced swim test. Quantum dot (qDot) labeling and immunohistochemistry were used to assess the biodistribution and fate of HUCPVCs and interactions with recipient innate immune cells.

RESULTS

A single intravenously delivered dose of HUCPVCs significantly reduced the systemic inflammation induced by LPS within the first 24 h after administration. HUCPVC treatment abrogated the upregulated expression of pro-inflammatory genes in the hippocampus and cortex and attenuated depressive-like behavior induced by LPS treatment. Biodistribution analysis revealed that HUCPVC-derived qDots rapidly accumulated in the lungs and demonstrated limited in vivo persistence. Furthermore, qDot signals were associated with major recipient innate immune cells and promoted a shift in macrophages toward a regulatory phenotype in the lungs.

CONCLUSIONS

Overall, this study demonstrates that HUCPVCs can successfully reduce systemic and neurological inflammation induced by LPS within the first 24 h after administration. Biodistribution and fate analyses suggest a critical role for the innate immune system in the HUCPVC-based immunomodulation mechanism.

Molecular mechanisms of coronary microvascular endothelial dysfunction in diabetes mellitus: focus on mitochondrial quality surveillance

Coronary microvascular endothelial dysfunction is both a culprit and a victim of diabetes, and can accelerate diabetes-related microvascular and macrovascular complications by promoting vasoconstrictive, pro-inflammatory and pro-thrombotic responses. Perturbed mitochondrial function induces oxidative stress, disrupts metabolism and activates apoptosis in endothelial cells, thus exacerbating the progression of coronary microvascular complications in diabetes. The mitochondrial quality surveillance (MQS) system responds to stress by altering mitochondrial metabolism, dynamics (fission and fusion), mitophagy and biogenesis. Dysfunctional mitochondria are prone to fission, which generates two distinct types of mitochondria: one with a normal and the other with a depolarized mitochondrial membrane potential. Mitochondrial fusion and mitophagy can restore the membrane potential and homeostasis of defective mitochondrial fragments. Mitophagy-induced decreases in the mitochondrial population can be reversed by mitochondrial biogenesis. MQS abnormalities induce pathological mitochondrial fission, delayed mitophagy, impaired metabolism and defective biogenesis, thus promoting the accumulation of unhealthy mitochondria and the activation of mitochondria-dependent apoptosis. In this review, we examine the effects of MQS on mitochondrial fitness and explore the association of MQS disorders with coronary microvascular endothelial dysfunction in diabetes. We also discuss the potential to treat diabetes-related coronary microvascular endothelial dysfunction using novel MQS-altering drugs.

Melatonin Attenuates Ischemia/Reperfusion-Induced Oxidative Stress by Activating Mitochondrial Fusion in Cardiomyocytes

Myocardial ischemia/reperfusion (I/R) injury can stimulate mitochondrial reactive oxygen species production. Optic atrophy 1- (OPA1-) induced mitochondrial fusion is an endogenous antioxidative mechanism that preserves the mitochondrial function. In our study, we investigated whether melatonin augments OPA1-dependent mitochondrial fusion and thus maintains redox balance during myocardial I/R injury. In hypoxia/reoxygenation- (H/R-) treated H9C2 cardiomyocytes, melatonin treatment upregulated OPA1 mRNA and protein expression, thereby enhancing mitochondrial fusion. Melatonin also suppressed apoptosis in H/R-treated cardiomyocytes, as evidenced by increased cell viability, diminished caspase-3 activity, and reduced Troponin T secretion; however, silencing OPA1 abolished these effects. H/R treatment augmented mitochondrial ROS production and repressed antioxidative molecule levels, while melatonin reversed these changes in an OPA1-dependent manner. Melatonin also inhibited mitochondrial permeability transition pore opening and maintained the mitochondrial membrane potential, but OPA1 silencing prevented these outcomes. These results illustrate that melatonin administration alleviates cardiomyocyte I/R injury by activating OPA1-induced mitochondrial fusion and inhibiting mitochondrial oxidative stress.

Development and Characterization of Alkaline Phosphatase-Positive Human Umbilical Cord Perivascular Cells

Human umbilical cord perivascular cells (HUCPVCs), harvested from human umbilical cord perivascular tissue, show potential for future use as an alternative to mesenchymal stromal cells. Here, we present the results for the characterization of the properties alkaline phosphatase-positive HUCPVCs (ALP(+)-HUCPVCs). These ALP(+)-HUCPVCs were created from HUCPVCs in this study by culturing in the presence of activated vitamin D3, an inhibitor of bone morphogenetic protein signaling and transforming growth factor-beta1 (TGF-β1). The morphological characteristics, cell proliferation, gene expression, and mineralization-inducing ability of ALP(+)-HUCPVCs were investigated at the morphological, biological, and genetic levels. ALP(+)-HUCPVCs possess high ALP gene expression and activity in cells and a slow rate of cell growth. The morphology of ALP(+)-HUCPVCs is fibroblast-like, with an increase in actin filaments containing alpha-smooth muscle actin. In addition to ALP expression, the gene expression levels of type I collagen, osteopontin, elastin, fibrillin-1, and cluster of differentiation 90 are increased in ALP(+)-HUCPVCs. ALP(+)-HUCPVCs do not have the ability to induce mineralization nodules, which may be due to the restriction of phosphate uptake into matrix vesicles. Moreover, ALP(+)-HUCPVCs may produce anti-mineralization substances. We conclude that ALP(+)-HUCPVCs induced from HUCPVCs by a TGF-β1 stimulation possess myofibroblast-like properties that have little mineralization-inducing ability.

Abnormal Mitochondria-Endoplasmic Reticulum Communication Promotes Myocardial Infarction

Myocardial infarction is characterized by cardiomyocyte death, and can be exacerbated by mitochondrial damage and endoplasmic reticulum injury. In the present study, we investigated whether communication between mitochondria and the endoplasmic reticulum contributes to cardiomyocyte death after myocardial infarction. Our data demonstrated that hypoxia treatment (mimicking myocardial infarction) promoted cardiomyocyte death by inducing the c-Jun N-terminal kinase (JNK) pathway. The activation of JNK under hypoxic conditions was dependent on overproduction of mitochondrial reactive oxygen species (mtROS) in cardiomyocytes, and mitochondrial division was identified as the upstream inducer of mtROS overproduction. Silencing mitochondrial division activators, such as B cell receptor associated protein 31 (BAP31) and mitochondrial fission 1 (Fis1), repressed mitochondrial division, thereby inhibiting mtROS overproduction and preventing JNK-induced cardiomyocyte death under hypoxic conditions. These data revealed that a novel death-inducing mechanism involving the BAP31/Fis1/mtROS/JNK axis promotes hypoxia-induced cardiomyocyte damage. Considering that BAP31 is localized within the endoplasmic reticulum and Fis1 is localized in mitochondria, abnormal mitochondria-endoplasmic reticulum communication may be a useful therapeutic target after myocardial infarction.

Irisin Attenuates Oxidative Stress, Mitochondrial Dysfunction, and Apoptosis in the H9C2 Cellular Model of Septic Cardiomyopathy through Augmenting Fundc1-Dependent Mitophagy

In the present study, we used lipopolysaccharide- (LPS-) stimulated H9C2 cardiomyocytes to investigate whether irisin treatment attenuates septic cardiomyopathy via Fundc1-related mitophagy. Fundc1 levels and mitophagy were significantly reduced in LPS-stimulated H9C2 cardiomyocytes but were significantly increased by irisin treatment. Irisin significantly increased ATP production and the activities of mitochondrial complexes I and III in the LPS-stimulated cardiomyocytes. Irisin also improved glucose metabolism and significantly reduced LPS-induced levels of reactive oxygen species by increasing the activities of antioxidant enzymes, glutathione peroxidase (GPX), and superoxide dismutase (SOD), as well as levels of reduced glutathione (GSH). TUNEL assays showed that irisin significantly reduced LPS-stimulated cardiomyocyte apoptosis by suppressing the activation of caspase-3 and caspase-9. However, the beneficial effects of irisin on oxidative stress, mitochondrial metabolism, and viability of LPS-stimulated H9C2 cardiomyocytes were abolished by silencing Fundc1. These results demonstrate that irisin abrogates mitochondrial dysfunction, oxidative stress, and apoptosis through Fundc1-related mitophagy in LPS-stimulated H9C2 cardiomyocytes. This suggests irisin is a potentially useful treatment for septic cardiomyopathy, though further investigations are necessary to confirm our findings.

Melatonin Attenuates Cardiac Ischemia-Reperfusion Injury through Modulation of IP3R-Mediated Mitochondria-ER Contact

Although the interplay between mitochondria and ER has been identified as a crucial regulator of cellular homeostasis, the pathogenic impact of alterations in mitochondria-ER contact sites (MERCS) during myocardial postischemic reperfusion (I/R) injury remains incompletely understood. Therefore, in our study, we explored the beneficial role played by melatonin in protecting cardiomyocytes against reperfusion injury via stabilizing mitochondria-ER interaction. In vitro exposure of H9C2 rat cardiomyocytes to hypoxia/reoxygenation (H/R) augmented mitochondrial ROS synthesis, suppressed both mitochondrial potential and ATP generation, and increased the mitochondrial permeability transition pore (mPTP) opening rate. Furthermore, H/R exposure upregulated the protein content of CHOP and caspase-12, two markers of ER stress, and enhanced the transcription of main MERCS tethering proteins, namely, Fis1, BAP31, Mfn2, and IP3R. Interestingly, all the above changes could be attenuated or reversed by melatonin treatment. Suggesting that melatonin-induced cardioprotection works through normalization of mitochondria-ER interaction, overexpression of IP3R abolished the protective actions offered by melatonin on mitochondria-ER fitness. These results expand our knowledge on the cardioprotective actions of melatonin during myocardial postischemic reperfusion damage and suggest that novel, more effective treatments for acute myocardial reperfusion injury might be achieved through modulation of mitochondria-ER interaction in cardiac cells.

Protective Effect of Nicorandil on Cardiac Microvascular Injury: Role of Mitochondrial Integrity

A major shortcoming of postischemic therapy for myocardial infarction is the no-reflow phenomenon due to impaired cardiac microvascular function including microcirculatory barrier function, loss of endothelial activity, local inflammatory cell accumulation, and increased oxidative stress. Consequently, inadequate reperfusion of the microcirculation causes secondary ischemia, aggravating the myocardial reperfusion injury. ATP-sensitive potassium ion (KATP) channels regulate the coronary blood flow and protect cardiomyocytes from ischemia-reperfusion injury. Studies in animal models of myocardial ischemia-reperfusion have illustrated that the opening of mitochondrial KATP (mito-KATP) channels alleviates endothelial dysfunction and reduces myocardial necrosis. By contrast, blocking mito-KATP channels aggravates microvascular necrosis and no-reflow phenomenon following ischemia-reperfusion injury. Nicorandil, as an antianginal drug, has been used for ischemic preconditioning (IPC) due to its mito-KATP channel-opening effect, thereby limiting infarct size and subsequent severe ischemic insult. In this review, we analyze the protective actions of nicorandil against microcirculation reperfusion injury with a focus on improving mitochondrial integrity. In addition, we discuss the function of mitochondria in the pathogenesis of myocardial ischemia.

Molecular Perspectives of Mitophagy in Myocardial Stress: Pathophysiology and Therapeutic Targets

A variety of complex risk factors and pathological mechanisms contribute to myocardial stress, which ultimately promotes the development of cardiovascular diseases, including acute cardiac insufficiency, myocardial ischemia, myocardial infarction, high-glycemic myocardial injury, and acute alcoholic cardiotoxicity. Myocardial stress is characterized by abnormal metabolism, excessive reactive oxygen species production, an insufficient energy supply, endoplasmic reticulum stress, mitochondrial damage, and apoptosis. Mitochondria, the main organelles contributing to the energy supply of cardiomyocytes, are key determinants of cell survival and death. Mitophagy is important for cardiomyocyte function and metabolism because it removes damaged and aged mitochondria in a timely manner, thereby maintaining the proper number of normal mitochondria. In this review, we first introduce the general characteristics and regulatory mechanisms of mitophagy. We then describe the three classic mitophagy regulatory pathways and their involvement in myocardial stress. Finally, we discuss the two completely opposite effects of mitophagy on the fate of cardiomyocytes. Our summary of the molecular pathways underlying mitophagy in myocardial stress may provide therapeutic targets for myocardial protection interventions.

Mitophagy coordinates the mitochondrial unfolded protein response to attenuate inflammation-mediated myocardial injury

Mitochondrial dysfunction is a fundamental challenge in septic cardiomyopathy. Mitophagy and the mitochondrial unfolded protein response (UPR^mt) are the predominant stress-responsive and protective mechanisms involved in repairing damaged mitochondria. Although mitochondrial homeostasis requires the coordinated actions of mitophagy and UPR^mt, their molecular basis and interactive actions are poorly understood in sepsis-induced myocardial injury. Our investigations showed that lipopolysaccharide (LPS)-induced sepsis contributed to cardiac dysfunction and mitochondrial damage. Although both mitophagy and UPR^mt were slightly activated by LPS in cardiomyocytes, their endogenous activation failed to prevent sepsis-mediated myocardial injury. However, administration of urolithin A, an inducer of mitophagy, obviously reduced sepsis-mediated cardiac depression by normalizing mitochondrial function. Interestingly, this beneficial action was undetectable in cardiomyocyte-specific FUNDC1 knockout (FUNDC1^CKO) mice. Notably, supplementation with a mitophagy inducer had no impact on UPR^mt, whereas genetic ablation of FUNDC1 significantly upregulated the expression of genes related to UPR^mt in LPS-treated hearts. In contrast, enhancement of endogenous UPR^mt through oligomycin administration reduced sepsis-mediated mitochondrial injury and myocardial dysfunction; this cardioprotective effect was imperceptible in FUNDC1^CKO mice. Lastly, once UPR^mt was inhibited, mitophagy-mediated protection of mitochondria and cardiomyocytes was partly blunted. Taken together, it is plausible that endogenous UPR^mt and mitophagy are slightly activated by myocardial stress and they work together to sustain mitochondrial performance and cardiac function. Endogenous UPR^mt, a downstream signal of mitophagy, played a compensatory role in maintaining mitochondrial homeostasis in the case of mitophagy inhibition. Although UPR^mt activation had no negative impact on mitophagy, UPR^mt inhibition compromised the partial cardioprotective actions of mitophagy. This study shows how mitophagy modulates UPR^mt to attenuate inflammation-related myocardial injury and suggests the potential application of mitophagy and UPR^mt targeting in the treatment of myocardial stress.

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Mitochondrial dysfunction is a fundamental challenge in septic cardiomyopathy.

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LPS-induced sepsis contributes to cardiac dysfunction and mitochondrial damage.

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Endogenous UPR^mt and mitophagy could be slightly activated by myocardial stress.

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Mitophagy modulates UPR^mt to attenuate inflammation-related myocardial injury.

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Mitophagy and UPR^mt targeting can be applied in treatment of myocardial stress.