HSPA12B Attenuated Acute Myocardial Ischemia/reperfusion Injury via Maintaining Endothelial Integrity in a PI3K/Akt/mTOR-dependent Mechanism

KMV-mediated cardiomyocyte-to-endothelial cell signaling drives capillary rarefaction to promote heart failure following pressure overload

Rationale: Pressure overload (PO)-induced heart failure (HF) is a global health burden with poor outcomes. Cardiomyocyte hypertrophy and capillary rarefaction are two features and drivers of PO-induced HF. Metabolism is altered in hypertrophic cardiomyocytes; however, the metabolites secreted by hypertrophic cardiomyocytes to paracrinally regulate capillary density remain to be identified. Methods: PO-induced HF was established by transverse aortic constriction in mice. Metabolite secretion was examined by nontargeted metabolomics and enzyme-linked immunosorbent assays. Gene expression was examined by RNA-sequencing and immunoblotting. Protein-promoter binding was examined by chromatin immunoprecipitation-PCR. Cardiomyocyte hypertrophy and cardiac capillary density were examined by immunostaining for -actinin and CD31, respectively. In vitro angiogenesis was indicated by proliferation, migration, tube formation, and angiogenic factor expression of endothelial cells (ECs). EC senescence was determined by SA--gal staining and p16 and p21 expression. Results: There was a negative correlation between cardiomyocyte size and capillary density in PO-induced failing hearts, and hypertrophic cardiomyocytes paracrinally inhibited angiogenesis of ECs. 3-Methyl-2-oxovaleric acid (KMV) was the most upregulated metabolite secreted by hypertrophic cardiomyocytes. Notably, KMV treatment resulted in EC senescence and angiogenesis inhibition in vitro and exaggerated PO-induced EC senescence, capillary rarefaction, and cardiac dysfunction of mice in vivo. Additionally, KMV increased expression and nuclear accumulation of mesenchyme homeobox 2 (Meox2) in ECs, whereas Meox2 knockdown diminished KMV-induced EC senescence and angiogenesis inhibition. Furthermore, Meox2 directly bound to the promoter of the senescence-related gene p21 in ECs, and this binding was enhanced by KMV. Conclusions: The data suggest that hypertrophic cardiomyocytes secrete elevated levels of KMV, which paracrinally increases nuclear accumulation of Meox2 in ECs, where Meox2 binds to the promoter of p21 and thereby triggers EC senescence and subsequent angiogenesis impairment, ultimately driving capillary rarefaction to promote PO-induced HF. The findings identified KMV as a novel metabolite secreted by hypertrophic cardiomyocytes that triggered EC senescence to drive PO-induced capillary rarefaction and subsequent HF development. Targeting this KMV-mediated cardiomyocyte-to-EC signaling has therapeutic potential in the management of PO-induced HF in patients.

HSPA12A maintains aerobic glycolytic homeostasis and Histone3 lactylation in cardiomyocytes to attenuate myocardial ischemia/reperfusion injury

Myocardial ischemia/reperfusion (MI/R) injury is a major cause of adverse outcomes of revascularization following myocardial infarction. Anaerobic glycolysis during myocardial ischemia is well studied, but the role of aerobic glycolysis during the early phase of reperfusion is incompletely understood. Lactylation of Histone H3 (H3) is an epigenetic indicator of the glycolytic switch. Heat shock protein A12A (HSPA12A) is an atypic member of the HSP70 family. In the present study, we report that, during reperfusion following myocardial ischemia, HSPA12A was downregulated and aerobic glycolytic flux was decreased in cardiomyocytes. Notably, HSPA12A KO in mice exacerbated MI/R-induced aerobic glycolysis decrease, cardiomyocyte death, and cardiac dysfunction. Gain- and loss-of-function studies demonstrated that HSPA12A was required to support cardiomyocyte survival upon hypoxia/reoxygenation (H/R) challenge and that its protective effects were mediated by maintaining aerobic glycolytic homeostasis for H3 lactylation. Further analyses revealed that HSPA12A increased Smurf1-mediated Hif1α protein stability, thus increasing glycolytic gene expression to maintain appropriate aerobic glycolytic activity to sustain H3 lactylation during reperfusion and, ultimately, improving cardiomyocyte survival to attenuate MI/R injury.

Regulation of Epithelial and Endothelial Barriers by Molecular Chaperones

The integrity and permeability of epithelial and endothelial barriers depend on the formation of tight junctions, adherens junctions, and a junction-associated cytoskeleton. The establishment of this junction-cytoskeletal module relies on the correct folding and oligomerization of its protein components. Molecular chaperones are known regulators of protein folding and complex formation in different cellular compartments. Mammalian cells possess an elaborate chaperone network consisting of several hundred chaperones and co-chaperones. Only a small part of this network has been linked, however, to the regulation of intercellular adhesions, and the systematic analysis of chaperone functions at epithelial and endothelial barriers is lacking. This review describes the functions and mechanisms of the chaperone-assisted regulation of intercellular junctions. The major focus of this review is on heat shock protein chaperones, their co-chaperones, and chaperonins since these molecules are the focus of the majority of the articles published on the chaperone-mediated control of tissue barriers. This review discusses the roles of chaperones in the regulation of the steady-state integrity of epithelial and vascular barriers as well as the disruption of these barriers by pathogenic factors and extracellular stressors. Since cytoskeletal coupling is essential for junctional integrity and remodeling, chaperone-assisted assembly of the actomyosin cytoskeleton is also discussed.

Salvianolic acids and its potential for cardio-protection against myocardial ischemic reperfusion injury in diabetes

The incidence of diabetes and related mortality rate increase yearly in modern cities. Additionally, elevated glucose levels can result in an increase of reactive oxygen species (ROS), ferroptosis, and the disruption of protective pathways in the heart. These factors collectively heighten the vulnerability of diabetic individuals to myocardial ischemia. Reperfusion therapies have been effectively used in clinical practice. There are limitations to the current clinical methods used to treat myocardial ischemia-reperfusion injury. As a result, reducing post-treatment ischemia/reperfusion injury remains a challenge. Therefore, efforts are underway to provide more efficient therapy. Salvia miltiorrhiza Bunge (Danshen) has been used for centuries in ancient China to treat cardiovascular diseases (CVD) with rare side effects. Salvianolic acid is a water-soluble phenolic compound with potent antioxidant properties and has the greatest hydrophilic property in Danshen. It has recently been discovered that salvianolic acids A (SAA) and B (SAB) are capable of inhibiting apoptosis by targeting the JNK/Akt pathway and the NF-κB pathway, respectively. This review delves into the most recent discoveries regarding the therapeutic and cardioprotective benefits of salvianolic acid for individuals with diabetes. Salvianolic acid shows great potential in myocardial protection in diabetes mellitus. A thorough understanding of the protective mechanism of salvianolic acid could expand its potential uses in developing medicines for treating diabetes mellitus related myocardial ischemia-reperfusion.

Proteomic Analysis Revealed the Potential Role of MAGE-D2 in the Therapeutic Targeting of Triple-Negative Breast Cancer

Among all the molecular subtypes of breast cancer, triple-negative breast cancer (TNBC) is the most aggressive one. Currently, the clinical prognosis of TNBC is poor because there is still no effective therapeutic target. Here, we carried out a combined proteomic analysis involving bioinformatic analysis of the proteome database, label-free quantitative proteomics, and immunoprecipitation (IP) coupled with mass spectrometry (MS) to explore potential therapeutic targets for TNBC. The results of bioinformatic analysis showed an overexpression of MAGE-D2 (melanoma antigen family D2) in TNBC. In vivo and in vitro experiments revealed that MAGE-D2 overexpression could promote cell proliferation and metastasis. Furthermore, label-free quantitative proteomics revealed that MAGE-D2 acted as a cancer-promoting factor by activating the PI3K-AKT pathway. Moreover, the outcomes of IP-MS and cross-linking IP-MS demonstrated that MAGE-D2 could interact with Hsp70 and prevent Hsp70 degradation, but evidence for their direct interaction is still lacking. Nevertheless, MAGE-D2 is a potential therapeutic target for TNBC, and blocking MAGE-D2 may have important therapeutic implications.

Research progress of quercetin in cardiovascular disease

Quercetin is one of the most common flavonoids. More and more studies have found that quercetin has great potential utilization value in cardiovascular diseases (CVD), such as antioxidant, antiplatelet aggregation, antibacterial, cholesterol lowering, endothelial cell protection, etc. However, the medicinal value of quercetin is mostly limited to animal models and preclinical studies. Due to the complexity of the human body and functional structure compared to animals, more research is needed to explore whether quercetin has the same mechanism of action and pharmacological value as animal experiments. In order to systematically understand the clinical application value of quercetin, this article reviews the research progress of quercetin in CVD, including preclinical and clinical studies. We will focus on the relationship between quercetin and common CVD, such as atherosclerosis, myocardial infarction, ischemia reperfusion injury, heart failure, hypertension and arrhythmia, etc. By elaborating on the pathophysiological mechanism and clinical application research progress of quercetin's protective effect on CVD, data support is provided for the transformation of quercetin from laboratory to clinical application.

Cinnamaldehyde protects donor heart from cold ischemia-reperfusion injury via the PI3K/AKT/mTOR pathway

With the growing shortage of organs, improvements in donor organ protection are needed to meet the increasing demands for transplantation. Here, the aim was to investigate the protective effect of cinnamaldehyde against ischemia-reperfusion injury (IRI) in donor hearts exposed to prolonged cold ischemia. Donor hearts were harvested from rats pretreated with or without cinnamaldehyde, then subjected to 24 h of cold preservation and 1 h of ex vivo perfusion. Hemodynamic changes, myocardial inflammation, oxidative stress, and myocardial apoptosis were evaluated. The PI3K/AKT/mTOR pathway involved in the cardioprotective effects of cinnamaldehyde was explored through RNA sequencing and western blot analysis. Intriguingly, cinnamaldehyde pretreatment remarkably improved cardiac function through increasing coronary flow, left ventricular systolic pressure, +dp/dtmax, and -dp/dtmax, decreasing coronary vascular resistance and left ventricular end-diastolic pressure. Moreover, our findings indicated that cinnamaldehyde pretreatment protected the heart from IRI by alleviating myocardial inflammation, attenuating oxidative stress, and reducing myocardial apoptosis. Further studies showed that the PI3K/AKT/mTOR pathway was activated after cinnamaldehyde treatment during IRI. The protective effects of cinnamaldehyde were abolished by LY294002. In conclusion, cinnamaldehyde pretreatment alleviated IRI in donor hearts suffering from prolonged cold ischemia. Cinnamaldehyde exerted cardioprotective effects through the activation of the PI3K/AKT/mTOR pathway.

HSPA12A controls cerebral lactate homeostasis to maintain hippocampal neurogenesis and mood stabilization

Mood instability, a subjective emotional state defined as rapid mood oscillations of up and down, is a symptom that occurs in several psychiatric disorders, particularly major depressive disorder and bipolar disorder. Heat shock protein A12A (HSPA12A) shows decreased expression in the brains of schizophrenia patients. However, the causal effects of HSPA12A in any psychiatric disorders are completely unknown. To investigate whether HSPA12A affects mood stability, Hspa12a-knockout mice (Hspa12a-/-) and wild-type (WT) littermates were subjected to tests of open field, forced swimming, elevated plus maze, and sucrose preference. Cerebral lactate levels were measured in cerebrospinal fluid (CSF). Adult hippocampal neurogenesis (AHN) was assessed by BrdU labeling. We found that acute mood stress increased hippocampal HSPA12A expression and CSF lactate levels in mice. However, Hspa12a-/- mice exhibited behaviors of mood instability (anhedonia, lower locomotor activity, antidepression, and anxiety), which were accompanied by impaired AHN, decreased CSF lactate levels, and downregulated hippocampal glycolytic enzyme expression. By contrast, HSPA12A overexpression increased lactate production and glycolytic enzyme expression of primary hippocampal neurons. Intriguingly, lactate administration alleviated the mood instability and AHN impairment in Hspa12a-/- mice. Further analyses revealed that HSPA12A was necessary for sustaining cerebral lactate homeostasis, which could be mediated by inhibiting GSK3β in hippocampal neurons, to maintain AHN and mood stabilization. Taken together, HSPA12A is defined as a novel regulator of mood stability and exerts therapeutic potential for mood disorder. Our findings establish a framework for determining mood disorder and AHN relevance of cerebral lactate homeostasis. HSPA12A is a novel mood stabilizer through inhibiting GSK3β in hippocampal neurons, thereby sustaining glycolysis-generated lactate to maintain cerebral lactate homeostasis, which ultimately leading to maintenance of hippocampal neurogenesis and mood stabilization.

Microvascular Leakage as Therapeutic Target for Ischemia and Reperfusion Injury

Reperfusion injury is a very common complication of various indicated therapies such as the re-opening of vessels in the myocardium or brain as well as reflow in hemodynamic shutdown (cardiac arrest, severe trauma, aortic cross-clamping). The treatment and prevention of reperfusion injury has therefore been a topic of immense interest in terms of mechanistic understanding, the exploration of interventions in animal models and in the clinical setting in major prospective studies. While a wealth of encouraging results has been obtained in the lab, the translation into clinical success has met with mixed outcomes at best. Considering the still very high medical need, progress continues to be urgently needed. Multi-target approaches rationally linking interference with pathophysiological pathways as well as a renewed focus on aspects of microvascular dysfunction, especially on the role of microvascular leakage, are likely to provide new insights.

Transcriptomic profiling and differential analysis reveal the renal toxicity mechanisms of mice under cantharidin exposure

Cantharidin (CTD), extracted from the traditional Chinese medicine mylabris, has shown significant curative effects against a variety of tumors, but its clinical application is limited by its high toxicity. Studies have revealed that CTD can cause toxicity in the kidneys; however, the underlying molecular mechanisms remain unclear. In this study, we investigated the toxic effects in mouse kidneys following CTD treatment by pathological and ultrastructure observations, biochemical index detection, and transcriptomics, and explored the underlying molecular mechanisms by RNA sequencing (RNA-seq). The results showed that after CTD exposure, the kidneys had different degrees of pathological damage, altered uric acid and creatinine levels in serum, and the antioxidant indexes in tissues were significantly increased. These changes were more pronounced at medium and high doses of CTD. RNA-seq analysis revealed 674 differentially expressed genes compared with the control group, of which 131 were upregulated and 543 were downregulated. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that many differentially expressed genes were closely related to the stress response, the CIDE protein family, and the transporter superfamily, as well as the MAPK, AMPK, and HIF-1 pathways. The reliability of the RNA-seq results was verified by qRT-PCR of the six target genes. These findings offer insight into the molecular mechanisms of renal toxicity caused by CTD and provide an important theoretical basis for the clinical treatment of CTD-induced nephrotoxicity.

mTORC1 beyond anabolic metabolism: Regulation of cell death

The mechanistic target of rapamycin complex 1 (mTORC1), a multi-subunit protein kinase complex, interrogates growth factor signaling with cellular nutrient and energy status to control metabolic homeostasis. Activation of mTORC1 promotes biosynthesis of macromolecules, including proteins, lipids, and nucleic acids, and simultaneously suppresses catabolic processes such as lysosomal degradation of self-constituents and extracellular components. Metabolic regulation has emerged as a critical determinant of various cellular death programs, including apoptosis, pyroptosis, and ferroptosis. In this article, we review the expanding knowledge on how mTORC1 coordinates metabolic pathways to impinge on cell death regulation. We focus on the current understanding on how nutrient status and cellular signaling pathways connect mTORC1 activity with ferroptosis, an iron-dependent cell death program that has been implicated in a plethora of human diseases. In-depth understanding of the principles governing the interaction between mTORC1 and cell death pathways can ultimately guide the development of novel therapies for the treatment of relevant pathological conditions.

Network Pharmacology-Based Combined with Experimental Validation Study to Explore the Underlying Mechanism of Agrimonia pilosa Ledeb. Extract in Treating Acute Myocardial Infarction

Purpose

The network pharmacology approach and validation experiment were performed to investigate the potential mechanisms of Agrimonia pilosa Ledeb. (APL) extract against acute myocardial infarction (AMI).

Methods

The primary compounds of APL extract were identified by High-Performance Liquid Chromatography (HPLC) analysis. The intersecting targets of active compounds and AMI were determined via network pharmacology analysis. A mouse model of AMI was established by subcutaneous injection of isoproterenol (Iso). Mice were treated with APL extract by intragastric administration. We assessed the effects of APL extract on the electrocardiography (ECG), cardiac representative markers, representative indicators of oxidative stress, pathological changes, and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, as well as apoptosis-related indicators in the mice.

Results

Five candidate compounds were identified in APL extract. Enrichment analyses indicated that APL extract could exert myocardial protective effects via the PI3K/Akt pathway. ST segment elevation and increased heart rate were obviously reversed in APL extract groups compared to Iso group. We also detected significant decreases in lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase MB (CK-MB), malondialdehyde (MDA), and reactive oxygen species (ROS), as well as a significant increase in superoxide dismutase activities (SOD) after APL extract treatment. In addition, APL extract markedly decreased the number of apoptotic cardiomyocytes after AMI. In the APL extract groups of AMI mice, there were increased expression levels of p-PI3K, p-Akt, and B-cell lymphoma-2 (Bcl-2) protein, and there were decreases in Bcl-2-associated X (Bax), cysteinyl aspartate-specific proteases-3 (caspase-3), and cleaved-caspase-3 protein expression levels, as well as the Bax/Bcl-2 ratio.

Conclusion

APL extract had a protective effect against Iso-induced AMI. APL extract could ameliorate AMI through antioxidant and anti-apoptosis actions which may be associated with the activation of the PI3K/Akt signaling pathway.

Modulation of mTOR Signaling in Cardiovascular Disease to Target Acute and Chronic Inflammation

Inflammation is a key component in the pathogenesis of cardiovascular diseases causing a significant burden of morbidity and mortality worldwide. Recent research shows that mammalian target of rapamycin (mTOR) signaling plays an important role in the general and inflammation-driven mechanisms that underpin cardiovascular disease. mTOR kinase acts prominently in signaling pathways that govern essential cellular activities including growth, proliferation, motility, energy consumption, and survival. Since the development of drugs targeting mTOR, there is proven efficacy in terms of survival benefit in cancer and allograft rejection. This review presents current information and concepts of mTOR activity in myocardial infarction and atherosclerosis, two important instances of cardiovascular illness involving acute and chronic inflammation. In experimental models, inhibition of mTOR signaling reduces myocardial infarct size, enhances functional remodeling, and lowers the overall burden of atheroma. Aside from the well-known effects of mTOR inhibition, which are suppression of growth and general metabolic activity, mTOR also impacts on specific leukocyte subpopulations and inflammatory processes. Inflammatory cell abundance is decreased due to lower migratory capacity, decreased production of chemoattractants and cytokines, and attenuated proliferation. In contrast to the generally suppressed growth signals, anti-inflammatory cell types such as regulatory T cells and reparative macrophages are enriched and activated, promoting resolution of inflammation and tissue regeneration. Nonetheless, given its involvement in the control of major cellular pathways and the maintenance of a functional immune response, modification of this system necessitates a balanced and time-limited approach. Overall, this review will focus on the advancements, prospects, and limits of regulating mTOR signaling in cardiovascular disease.

HSPA12A Stimulates p38/ERK-AP-1 Signaling to Promote Angiogenesis and Is Required for Functional Recovery Postmyocardial Infarction

Angiogenesis plays a critical role in wound healing postmyocardial infarction (MI). However, there is still a lack of ideal angiogenic therapeutics for rescuing ischemic hearts clinically, suggesting that a more understanding regarding angiogenesis regulation is urgently needed. Heat shock protein A12A (HSPA12A) is an atypical member of the HSP70 family. Here, we demonstrated that HSPA12A was upregulated during endothelial tube formation, a characteristic of in vitro angiogenesis. Intriguingly, overexpression of HSPA12A promoted in vitro angiogenic characteristics including proliferation, migration, and tube formation of endothelial cells. By contrast, deficiency of HSPA12A impaired myocardial angiogenesis and worsened cardiac dysfunction post-MI in mice. The expression of genes related to angiogenesis (VEGF, VEGFR2, and Ang-1) was decreased by HSPA12A deficiency in MI hearts of mice, whereas their expression was increased by HSPA12A overexpression in endothelial cells. HSPA12A overexpression in endothelial cells increased phosphorylation levels and nuclear localization of AP-1, a transcription factor dominating angiogenic gene expression. Also, HSPA12A increased p38 and ERK phosphorylation levels, whereas inhibition of p38 or ERKs diminished the HSPA12A-promoted AP-1 phosphorylation and nuclear localization, as well as VEGF and VEGFR2 expression in endothelial cells. Notably, inhibition of either p38 or ERKs diminished the HSPA12A-promoted in vitro angiogenesis characteristics. The findings identified HSPA12A as a novel angiogenesis activator, and HSPA12A might represent a viable strategy for the management of myocardial healing in patients with ischemic heart diseases.

Oxycodone protects cardiac microvascular endothelial cells against ischemia/reperfusion injury by binding to Sigma-1 Receptor

Endothelial dysfunction is an important mechanism involved in myocardial ischemia-reperfusion (I/R) injury. We aimed to explore the effects of Oxycodone on myocardial I/R injury in vivo and in vitro to reveal its mechanisms related to Sigma-1 Receptor (SIGMAR1). A rat model of I/R-induced myocardial injury was developed. The ischemic area and myocardial histopathological changes after oxycodone addition were evaluated by TTC staining and H&E staining. LDH, CK-MB and cTnI levels were used to assess myocardial function. Then, the endothelial integrity was reflected by the expressions of ZO-1, Claudin-1 and Occludin. Afterward, ELISA, RT-qPCR, western blot and immunofluorescence assays were adopted for the detection of inflammation-related genes. SIGMAR1 expression in myocardial tissues induced by I/R and cardiac microvascular endothelial cells (CMECs) under hypoxic/reoxygenation (H/R) was determined using RT-qPCR and western blotting. Subsequently, after SIGMAR1 silencing or BD1047 addition (a SIGMAR1 antagonist), cell apoptosis and endothelial integrity were analyzed in the presence of Oxycodone in H/R-stimulated CMECs. Results indicated that Oxycodone decreased the ischemic area and improved myocardial function in myocardial I/R injury rat. Oxycodone improved myocardial histopathological injury and elevated endothelial integrity, evidenced by upregulated ZO-1, Claudin-1 and Occludin expressions. Moreover, inflammatory response was alleviated after Oxycodone administration. Molecular docking suggested that SIGMAR1 could directly bind to Oxycodone. Oxycodone elevated SIGMAR1 expression and SIGMAR1 deletion or BD1047 addition attenuated the impacts of Oxycodone on apoptosis and endothelial integrity of CMECs induced by H/R. Collectively, Oxycodone alleviates myocardial I/R injury in vivo and in vitro by binding to SIGMAR1.

CREG mitigates neonatal HIE injury through survival promotion and apoptosis inhibition in hippocampal neurons via activating AKT signaling

Neonatal hypoxic ischemic encephalopathy (Neonatal HIE) is a common but serious disease caused by perinatal asphyxia injury in newborns. Elevated neuronal apoptosis plays an important role in the injury process post hypoxia ischemia of the brain, which accurate mechanism is still worthy to be studied. Cellular repressor of E1A-stimulated genes (CREG) possesses the protective effect in ischemia-reperfusion in multiple organs, including livers and hearts. The main purpose of this work was to investigate whether CREG was involved in alleviating neonatal HIE and explore the possible mechanisms. We found that CREG expression was down-regulated in the hippocampus of neonatal HIE rats as well as oxygen-glucose deprivation/reperfusion (OGD/R)-treated hippocampal neurons. Besides, CREG overexpression promoted survival while inhibited apoptosis in OGD/R-induced hippocampal neurons accompanied by AKT signaling activation, which could be reversed by CREG silence. In addition, the protective effects of CREG overexpression could be antagonized by AKT deactivation, indicating the function of CREG was attributed by regulating AKT pathway. Collectedly, we demonstrated that CREG protected hippocampal neurons from hypoxic ischemia-induced injury through regulating survival and apoptosis via activating AKT signaling pathway. This article is protected by copyright. All rights reserved.

Downregulation of HSPA12A underlies myotoxicity of local anesthetic agent bupivacaine through inhibiting PGC1α-mediated mitochondrial integrity

Local anesthetics (LAs) are widely used for intraoperative anesthesia and postoperative analgesia. However, LAs (e.g. Bupivacaine) can evoke myotoxicity that closely associated to mitochondrial damage. PGC1a is a mast co-factor for mitochondrial quality control. We have recently demonstrated that PGC1a can be activated by HSPA12A in hepatocytes, suggesting a possibility that HSPA12A protects from LAs myotoxicity through activating PGC1α-mediated mitochondrial integrity. Here, we reported that HSPA12A was downregulated during Bupivacaine-induced myotoxicity in skeletal muscles of mice in vivo and C2c12 myoblast cultures in vitro. Intriguingly, overexpression of HSPA12A attenuated the Bupivacaine-induced C2c12 cell death. We also noticed that the Bupivacaine-induced decrease of glucose consumption and ATP production was improved by HSPA12A overexpression. Moreover, overexpression of HSPA12A in C2c12 cells attenuated the Bupivacaine-induced decrease of mitochondrial contents and increase of mitochondrial fragmentation. The Bupivacaine-induced reduction of PGC1α expression and nuclear localization was markedly attenuated by HSPA12A overexpression. Importantly, pretreatment with a selective PGC1α inhibitor (SR-18292) abolished the protection of HSPA12A from Bupivacaine-induced death and mitochondrial loss in C2c12 cells. Altogether, the findings indicate that downregulation of HSPA12A underlies myotoxicity of Local anesthetic agent Bupivacaine through inhibiting PGC1α-mediated Mitochondrial Integrity. Thus, HSPA12A might represent a viable strategy for preventing myotoxicity of LAs.

Inhibition of PI3K/mTOR/KATP channel blunts sodium thiosulphate preconditioning mediated cardioprotection against ischemia-reperfusion injury

Recent studies have shown that pre and postconditioning the heart with sodium thiosulfate (STS) attenuate ischemia-reperfusion (IR) injury. However, the underlying mechanism involved in the cardioprotective signaling pathway is not fully explored. This study examined the existing link of STS mediated protection (as pre and post-conditioning agents) with PI3K, mTOR, and mPTP signaling pathways using its respective inhibitors. STS was administered to the isolated perfused rat heart through Kreb's Heinselit buffer before ischemia (precondition: SIPC) and reperfusion (postcondition: SPOC) in the presence and absence of the PI3K, mTOR, and mPTP signaling pathway inhibitors (wortmannin, rapamycin, and glibenclamide respectively). SIPC failed to improve the IR injury-induced altered cardiac hemodynamics, increased infarct size, and the release of cardiac injury markers in the presence of these inhibitors. On the other hand, the SPOC protocol effectively rendered the cardioprotection even in the PI3K/mTOR/K_ATP inhibitors presence. Interestingly, the SIPC's identified mode of action viz reduction in oxidative stress and the preservation of mitochondrial function were lost in the inhibitors' presence. Based on the above results, we conclude that the underlying mechanism of SIPC mediated cardioprotection works via the PI3K/mTOR/K_ATP signaling pathway axis activation.

SYVN1/GPX5 axis affects ischemia/reperfusion induced apoptosis of AC16 cells by regulating ROS generation

Ischemia/reperfusion (I/R) induced injury is a major cause of coronary heart disease (CHD). Increased production of reactive oxygen species (ROS) can lead to an I/R injury in CHD, and the ROS level can be regulated by Glutathione peroxidase (GPX) enzyme family. In this study, we investigated the role and underlying molecular mechanism of GPX5 in I/R-induced AC16 cells. We found that the serum level of GPX5 was down-regulated in patients with CHD and I/R-induced AC16 cells. Overexpression of GPX5 inhibited I/R-induced apoptosis by suppressing the production of ROS. On the other hand, knock-down of GPX5 promoted apoptosis in AC16 cells by up-regulating the level of ROS. Furthermore, we found that GPX5 was regulated by synovial apoptosis inhibitor 1 (SYVN1)-mediated ubiquitination in AC16 cells. In I/R-induced AC16 cells, the expression of SYVN1 was up-regulated, and SYVN1 knock-down decreased the ROS levels and apoptotic rate but increased GPX5 levels. Moreover, GPX5 knockdown promoted ROS production and apoptosis, while its effects were attenuated by SYVN1 knockdown. Furthermore, SYVN1 was up-regulated while GPX5 was down-regulated in the myocardial tissue of I/R-injured rats. Taken together, our data demonstrate that GPX5 inhibits I/R-induced apoptosis of AC16 cells by down-regulating ROS level, and its stabilization is regulated by SYVN1-mediated ubiquitination.

Ischemic Heart Disease Pathophysiology Paradigms Overview: From Plaque Activation to Microvascular Dysfunction

Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.

RP11-462C24.1 suppresses proliferation and invasion of colorectal carcinoma cells by regulating HSP70 through PI3K/AKT signaling pathway

Colorectal cancer (CRC) is the third leading cause of cancer-related death around the world. In this study, we investigated the roles of LncRNA RP11-462C24.1 in CRC. The expressions of RP11-462C24.1 in CRC tissues and cells were measured. Then, the effects of RP11-462C24.1 on CRC proliferation, cell cycle, apoptosis, and invasion were evaluated both in vivo and in vitro; Last, the underlying mechanisms of concerning the signaling pathway regulated by RP11-462C24.1 was determined. From the results, we found that RP11-462C24.1 was significantly decreased in CRC tumor tissues and the CRC cell lines, which were most significant in SW480 and HT-29 cell lines; moreover, transient overexpression of RP11-462C24.1 suppressed the growth and migration while promoted apoptosis of SW480 and HT-29 cells, while knockdown of RP11-462C24.1 has shown the opposite effects; RP11-462C24.1 may also inhibit the growth of CRC tumors in xenograft mice models; additionally, 70 kD heat shock proteins (HSP70) has been identified as one of the most significantly deferentially expressed genes by RNA-seq, and we further confirmed that RP11-462C24.1 may affect the growth and metathesis of CRC cells via regulating HSP70 and PI3K/AKT signaling pathway. In summary, these results indicated that RP11-462C24 may function as a tumor suppressor in the development of CRC.

HSPA12B Secreted by Tumor-Associated Endothelial Cells Might Induce M2 Polarization of Macrophages via Activating PI3K/Akt/mTOR Signaling

Purpose

The intratumoral microenvironment of head and neck squamous cell carcinoma (HNSC) is highly immunosuppressive. In this study, we explored the potential functional role of HSPA12B secreted by tumor-associated endothelial cells (TECs) in M2 polarization of macrophages.

Materials and Methods

Bulk-seq data from TCGA-HNSC and single-cell RNA-seq data from GSE103322 (with over 5000 cells from 18 primary HNSC cases) were used for bioinformatic analysis. RAW264.7 cell line was used for in vitro studies.

Results

TECs in HNSC had significantly higher expression and secretion of HSPA12B, compared to normal human umbilical vein endothelial cells (HUVECs). Exogenous HSPA12B treatment increased the expression of M2 macrophage marker CD163 and CD206 on RAW264.7 cells in a dose-dependent manner but had no significant influence on CD86, an M1 macrophage marker. OLR1, a known receptor of HSP70 proteins, was specifically expressed in tumor-associated macrophages (TAMs) in HNSC. OLR1 knockdown significantly impaired HSPA12B uptake by RAW264.7 cells and weakened HSPA12B-induced CD163 and CD206 upregulation. HSPA12B treatment increased the expression of p-PI3K, p-Akt and p-mTOR in a dose-dependent manner in RAW264.7 cells. OLR1 inhibition and LY294002 treatment significantly weakened the effects HSPA12B on activating the PI3K/Akt/mTOR signaling and M2 marker expression.

Conclusion

Based on these findings, we speculated that aberrantly expressed and secreted HSPA12B by TECs could be taken by macrophages partly via OLR1, leading to subsequent activation of the PI3K/Akt/mTOR signaling pathway and elevated expression of M2 markers. This mechanism shows a novel cross-talk between TECs and TAMs, which contributes to the intratumoral immunosuppressive microenvironment.

Long non‑coding RNA SNHG16 inhibits the oxygen‑glucose deprivation and reoxygenation‑induced apoptosis in human brain microvascular endothelial cells by regulating miR‑15a‑5p/bcl‑2

MicroRNA (miR) 15a-5p can promote ischemia/reperfusion (I/R)-induced apoptosis of cerebral vascular endothelial cells, which is inhibited by long non-coding RNAs (lncRNAs). The present study investigated the potential of lncRNAs targeting miR-15a-5p to regulate oxygen-glucose deprivation and reoxygenation (OGD-R)-induced apoptosis of human brain microvascular endothelial cells (hBMECs). hBMECs were transfected with or without miR-15a-5p or its mutant, together with p-small nucleolar RNA host gene 16 (SNHG16) or its mutant. Following OGD-R, proliferation, apoptosis and miR-15a-5p, SNHG16 and Bcl-2 expression levels were determined using MTT, flow cytometry, reverse transcription-quantitative PCR or western blotting. The potential interaction of SNHG16 with miR-15a-5p was analyzed by pull-down, luciferase and immunoprecipitation assays. OGD-R induced apoptosis of hBMECs and increased miR-15a-5p expression levels in a time-dependent manner. miR-15a-5p overexpression decreased the proliferation of hBMECs and promoted apoptosis by decreasing Bcl-2 expression levels. SNHG16 was pulled-down by miR-15a-5p and anti-Ago2. miR-15a-5p overexpression significantly decreased SNHG16-regulated luciferase activity and hBMEC survival by increasing apoptosis. SNHG16 overexpression decreased miR-15a-5p expression levels in hBMECs. SNHG16 gradually decreased following OGD-R and its overexpression decreased miR-15a-5p expression levels and promoted the proliferation of hBMECs by decreasing apoptosis. SNHG16 enhanced Bcl-2 expression levels in hBMECs, which was abrogated by miR-15a-5p. Bioinformatics suggest that SNHG16 may antagonize the binding of miR-15a-5p to the 3′UTR of Bcl-2 mRNA. These findings suggest that SNHG16 may protect hBMECs from OGD-R-induced apoptosis by antagonizing the miR-15a-5p/bcl-2 axis. Thus, targeting SNHG16-based mechanisms may provide novel therapeutic strategies for treatment of ischemic stroke.

T-UCRs with digestive and respiratory diseases

From the perspective of histoembryology, the lung, gaster, and intestines that derived from the endoderm of the gastrula are structurally homologous. The interplay of intestines and lung in many pathologic changes is called the gut-lung axis. RNAs transcribed from ultraconserved regions (T-UCRs) are highly evolutionarily conserved in many mammalian genomes and have been found to be important in the pathogenesis and diagnosis of many diseases. More and more studies in recent years have shown that T-UCRs play important roles both in digestive and respiratory diseases. Taking the gut-lung axis as the entry point, this review summarizes the T-UCRs related to digestive and respiratory diseases in recent years. Meanwhile, these T-UCRs and their targets can lay a foundation for future drug research.

MicroRNA-363-3p serves as a diagnostic biomarker of acute myocardial infarction and regulates vascular endothelial injury by targeting KLF2

Background

Acute myocardial infarction (AMI) is a serious cardiovascular disease. This study aimed to investigate the diagnostic value of microRNA-363-3p (miR-363-3p) in AMI patients and explore the effects of miR-363-3p on vascular endothelial injury in an AMI rat model.

Methods

The Expression of miR-363-3p was measured by quantitative real-time PCR. A receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic value of miR-363-3p in AMI patients. The biomarkers of endothelial injury were estimated using enzyme-linked immunosorbent assays, and the correlation of miR-363-3p with these markers was assessed. AMI rat model was constructed using coronary artery ligation, and the effects of miR-363-3p on endothelial injury and endothelial cell proliferation were analyzed.

Results

Serum expression of miR-363-3p was upregulated in the AMI patients compared with healthy controls. The increased serum miR-363-3p serves a candidate diagnostic biomarker of AMI. The correlation analysis indicated that serum miR-363-3p expression was positively correlated with the concentration of endothelial injury biomarkers in AMI patients. Furthermore, the increased endothelial injury biomarkers in AMI rats were all inhibited by the knockdown of miR-363-3p, and the cell proliferation of human umbilical vein endothelial cells was obviously enhanced by the reduction of miR-363-3p. The prediction results shown that Kruppel-like factor 2 (KLF2) is a target of miR-363-3p, and their interaction was proved using a luciferase reporter assay.

Conclusions

Collectively, overexpression of miR-363-3p acts as a diagnostic biomarker for patients with AMI, and the downregulation of miR-363-3p improves AMI-associated endothelial injury by targeting KLF2, which indicated that miR-363-3p has a potential to develop the treatment of AMI.

Alpha-lipoic acid inhibits proliferation and migration of human vascular endothelial cells through downregulating HSPA12B/VEGF signaling axis

Endothelial cells play essential roles in angiogenesis. Heat shock protein A12B (HSPA12B), a novel member of the multigene Hsp70 family, expresses specifically in endothelial cells. Alpha-lipoic acid (LA) has been used for the treatment of human diabetic complications for more than 20 years. However, little is known whether LA impacts endothelial proliferation and migration. To address these questions, primary human umbilical vein endothelial cells (HUVECs) were isolated and treated with LA. We found that LA reduced viable HUVECs but not caused LDH leakage and nuclear condensation, suggesting an inhibitory effect of LA on HUVEC proliferation. We also noticed that LA impeded wound closure of HUVEC monolayers. The expressions of C-Myc, VEGF, and eNOS and phosphorylation of focal adhesion kinase were reduced by LA. Moreover, LA decreased the expression of heat shock protein A12B (HSPA12B). Notably, overexpression of HSPA12B in endothelial cells prevented the LA-induced loss of VEGF. More importantly, HSPA12B overexpression attenuated the LA-induced inhibition of endothelial proliferation and migration. Collectively, the results demonstrated that LA inhibited proliferative and migratory abilities in human vascular endothelial cells through the downregulation of the HSPA12B/VEGF signaling axis. The data suggest that besides the treatment in diabetic complications, LA might represent a viable therapeutic potential for human diseases that involve high angiogenic activities such as cancers.

PDRPS7 protects cardiac cells from hypoxia/reoxygenation injury through inactivation of JNKs

Myocardial ischemia/reperfusion (I/R) injury is a major complication of reperfusion therapy in myocardial infarction. Ischemic myocardium produces a variety of peptides. We recently identified PDRPS7 as a novel peptide in cardiomyocytes that can be induced by hypoxia. However, the role of PDRPS7 is unknown. Here, we investigated the effects of PDRPS7 on hypoxia/reoxygenation (H/R)‐induced injury in rat cardiomyoblast H9c2 cells and NRCMs. We found that PDRPS7 improved cell survival and attenuated lactate dehydrogenase leakage following H/R in H9c2 cells and NRCMs. PDRPS7 also alleviated H/R‐induced pulsation reduction in NRCMs. Moreover, H/R‐induced cell apoptosis was decreased in the presence of PDRPS7. H/R‐induced reactive oxygen species generation was reduced by PDRPS7; in addition, PDRPS7 did not impact H₂O₂‐induced cell injury. Signaling analysis demonstrated that H/R increased the phosphorylation levels of JNKs, ERKs, and p38 mitogen‐activated protein kinases. However, PDRPS7 only attenuated H/R‐induced JNK phosphorylation, but not phosphorylation of ERKs and p38. PDRPS7 protected cardiomyocytes from apoptosis by inhibiting JNK phosphorylation and c‐Jun phosphorylation pathways, markedly upregulating anti‐apoptotic Bcl‐2 expression and inhibiting that of pro‐apoptotic Bax and cleaved caspase‐3. Importantly, pharmacological activation of JNKs diminished the protective effect of PDRPS7 in terms of cell survival against H/R stimulation. In summary, our study identified PDRPS7 as a novel cardioprotective peptide against H/R challenge and this action was mediated, at least in part, through inactivation of JNKs.

Cardiomyocyte-specific deficiency of HSPB1 worsens cardiac dysfunction by activating NFκB-mediated leucocyte recruitment after myocardial infarction

Aims

Inadequate healing after myocardial infarction (MI) leads to heart failure and fatal ventricular rupture, while optimal healing requires timely induction and resolution of inflammation. This study tested the hypothesis that heat shock protein B1 (HSPB1), which limits myocardial inflammation during endotoxemia, modulates wound healing after MI.

Methods and results

To test this hypothesis, cardiomyocyte-specific HSPB1 knockout (Hspb1-/-) mice were generated using the Cre-LoxP recombination system. MI was induced by ligation of the left anterior descending coronary artery in Hspb1-/- and wild-type (WT) littermates. HSPB1 was up-regulated in cardiomyocytes of WT animals in response to MI, and deficiency of cardiomyocyte HSPB1 increased MI-induced cardiac rupture and mortality within 21 days after MI. Serial echocardiography showed more aggravated remodelling and cardiac dysfunction in Hspb1-/- mice than in WT mice at 1, 3, and 7 days after MI. Decreased collagen deposition and angiogenesis, as well as increased MMP2 and MMP9 activity, were also observed in Hspb1-/- mice compared with WT controls after MI, using immunofluorescence, polarized light microscopy, and zymographic analyses. Notably, Hspb1-/- hearts exhibited enhanced and prolonged leucocyte infiltration, enhanced expression of inflammatory cytokines, and enhanced TLR4/MyD88/NFκB activation compared with WT controls after MI. In-depth molecular analyses in both mice and primary cardiomyocytes demonstrated that cardiomyocyte-specific knockout of HSPB1 increased nuclear factor-κB (NFκB) activation, which promoted the expression of proinflammatory mediators. This led to increased leucocyte recruitment, thereby to excessive inflammation, ultimately resulting in adverse remodelling, cardiac dysfunction, and cardiac rupture following MI.

Conclusion

These data suggest that HSPB1 acts as a negative regulator of NFκB-mediated leucocyte recruitment and the subsequent inflammation in cardiomyocytes. Cardiomyocyte HSPB1 is required for wound healing after MI and could be a target for myocardial repair in MI patients.

Endothelial tight junctions and their regulatory signaling pathways in vascular homeostasis and disease

Endothelial tight junctions (TJs) regulate the transport of water, ions, and molecules through the paracellular pathway, serving as an important barrier in blood vessels and maintaining vascular homeostasis. In endothelial cells (ECs), TJs are highly dynamic structures that respond to multiple external stimuli and pathological conditions. Alterations in the expression, distribution, and structure of endothelial TJs may lead to many related vascular diseases and pathologies. In this review, we provide an overview of the assessment methods used to evaluate endothelial TJ barrier function both in vitro and in vivo and describe the composition of endothelial TJs in diverse vascular systems and ECs. More importantly, the direct phosphorylation and dephosphorylation of TJ proteins by intracellular kinases and phosphatases, as well as the signaling pathways involved in the regulation of TJs, including and the protein kinase C (PKC), PKA, PKG, Ras homolog gene family member A (RhoA), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and Wnt/β-catenin pathways, are discussed. With great advances in this area, targeting endothelial TJs may provide novel treatment for TJ-related vascular pathologies.

Prolonged neutrophil retention in the wound impairs zebrafish heart regeneration after cryoinjury

Neutrophils are the first line defenders in the innate immune response, and rapidly migrate to an infected or injured area. Recently, bidirectional migration of neutrophils to the wound and the corresponding functions have become popular research pursuits. In zebrafish larvae, CXCR1/CXCL8 is the predominant chemoattractant pathway to recruit neutrophil to wound, while CXCR2/CXCL8 pathway mediate neutrophil dispersal in wound after injury. Here, we found that both CXCR1/CXCL8 and LTB4/BLT1 signals are activated in zebrafish heart after cryoinjury. And with a CXCR1/2 selective inhibitor (SB225002) treatment, the recruitment of neutrophils was not affected, but reverse migration of neutrophils was inhibited after cryoinjury of heart. We suggested that the neutrophil recruitment to cryoinjured area might be mediated by LTB4/BLT1 signals at the presence of SB225002. Therefore, SB225002 treatment resulted more accumulation and long retention of neutrophils in the injured heart. The long retention of neutrophils in the wound promoted revascularization in the injured heart; however, the AKT/mTOR pathway was inhibited and the regeneration was impaired. Our findings suggest that retention of neutrophils is a well-orchestrated process and might regulate regeneration by the AKT/mTOR pathway.

Cardioprotective effect of IGF-1 against myocardial ischemia/reperfusion injury through activation of PI3K/Akt pathway in rats in vivo

Objective

It remains unknown whether insulin-like growth factor-1 (IGF-1) can attenuate myocardial ischemia/reperfusion (I/R) injury in vivo by activating the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway. This study investigated the possible interaction of IGF-1 with the PI3K/Akt pathway in cardioprotection against in vivo myocardial I/R injury in rats.

Methods

We established a myocardial I/R model in rats through left anterior descending artery ligation for 40 minutes followed by 6 hours reperfusion. The PI3K/Akt inhibitor, LY294002 (0.3 mg/kg), was injected through the caudal vein 30 minutes before myocardial ischemia, and IGF-1 (1 µg/kg or 5 µg/kg) was injected through the caudal vein 10 minutes before myocardial ischemia.

Results

IGF-1 treatment decreased myocardial infarct size; myocardial cell apoptosis; and serum lactate dehydrogenase, creatine kinase MB, and cardiac troponin I levels in rats with myocardial I/R in vivo. Moreover, IGF-1 treatment led to significant increases in expression levels of p-Akt (Ser473) and B cell lymphoma 2, while reducing expression levels of caspase-9 mRNA and cleaved caspase-9 protein in rats with myocardial I/R. However, pretreatment with LY294002 significantly reduced the cardioprotective effects of IGF-1.

Conclusion

Treatment with IGF-1 may confer cardiac protection against in vivo myocardial I/R injury via the PI3K/Akt pathway in rats.

Salvia miltiorrhiza in Treating Cardiovascular Diseases: A Review on Its Pharmacological and Clinical Applications

Bioactive chemical constitutes from the root of Salvia miltiorrhiza classified in two major groups, viz., liposoluble tanshinones and water-soluble phenolics. Tanshinone IIA is a major lipid-soluble compound having promising health benefits. The in vivo and in vitro studies showed that the tanshinone IIA and salvianolate have a wide range of cardiovascular and other pharmacological effects, including antioxidative, anti-inflammatory, endothelial protective, myocardial protective, anticoagulation, vasodilation, and anti-atherosclerosis, as well as significantly help to reduce proliferation and migration of vascular smooth muscle cells. In addition, some of the clinical studies reported that the S. miltiorrhiza preparations in combination with Western medicine were more effective for treatment of various cardiovascular diseases including angina pectoris, myocardial infarction, hypertension, hyperlipidemia, and pulmonary heart diseases. In this review, we demonstrated the potential applications of S. miltiorrhiza, including pharmacological effects of salvianolate, tanshinone IIA, and its water-soluble derivative, like sodium tanshinone IIA sulfonate. Moreover, we also provided details about the clinical applications of S. miltiorrhiza preparations in controlling the cardiovascular diseases.

Platycodin D protects cortical neurons against oxygen-glucose deprivation/reperfusion in neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic-ischemic encephalopathy is one of the leading causes of death in infants. Increasing evidence indicates that oxidative stress and apoptosis are major contributors to hypoxic-ischemic injury and can be used as particularly promising therapeutic targets. Platycodin D (PLD) is a triterpenoid saponin that exhibits antioxidant properties. The aim of this study was to evaluate the effects of PLD on hypoxic-ischemic injury in primary cortical neurons. We found that oxygen-glucose deprivation/reperfusion (OGD/R) induced inhibition of cell viability and cytotoxicity, which were attenuated by PLD treatment. PLD treatment inhibited oxidative stress induced by OGD/R, which was evidenced by the reduced level of reactive oxygen species and increased activities of catalase, superoxide dismutase, and glutathione peroxidase. Histone-DNA enzyme-linked immunosorbent assay revealed that apoptosis was significantly decreased after PLD treatment in OGD/R-treated cortical neurons. The increased bax expression and decreased bcl-2 expression induced by OGD/R were reversed by PLD treatment. Furthermore, PLD treatment caused the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway in OGD/R-stimulated cortical neurons. Suppression of this pathway blocked the protective effects of PLD on OGD/R-induced cell injury. These findings suggested that PLD executes its protective effects on OGD/R-induced cell injury via regulating the PI3K/Akt/mTOR pathway in cortical neurons.

HSPA12A is required for adipocyte differentiation and diet-induced obesity through a positive feedback regulation with PPARγ

Obesity is one of the most serious public health problems. Peroxisome proliferator-activated receptor γ (PPARγ) plays the master role in adipocyte differentiation for obesity development. However, optimum anti-obesity drug has yet been developed, mandating more investigation to identify novel regulator in obesity pathogenesis. Heat shock protein 12A (HSPA12A) encodes a novel member of the HSP70 family. Here, we report that obese patients showed increased adipose HSPA12A expression, which was positively correlated with increase of body mass index. Intriguingly, knockout of HSPA12A (Hspa12a^−/−) in mice attenuated high-fat diet (HFD)-induced weight gain, adiposity, hyperlipidemia, and hyperglycemia compared to their wild type (WT) littermates. Increased insulin sensitivity was observed in Hspa12a^−/− mice compared to WT mice. The HFD-induced upregulation of PPARγ and its target adipogenic genes in white adipose tissues (WAT) of Hspa12a^−/− mice were also attenuated. Loss- and gain-of-function studies revealed that the differentiation of primary adipocyte precursors, as well as the expression of PPARγ and target adipogenic genes during the differentiation, was suppressed by HSPA12A deficiency whereas promoted by HSPA12A overexpression. Importantly, PPARγ inhibition by GW9662 reversed the HSPA12A-mediated adipocyte differentiation. On the other hand, HSPA12A expression was downregulated by PPARγ inhibition but upregulated by PPARγ activation in primary adipocytes. A direct binding of PPARγ to the PPAR response element in the Hspa12a promoter region was confirmed by chromatin immunoprecipitation assay, and this binding was increased after differentiation of primary adipocytes. These findings indicate that HSPA12A is a novel regulator of adipocyte differentiation and diet-induced obesity through a positive feedback regulation with PPARγ. HSPA12A inhibition might represent a viable strategy for the management of obesity in humans.

HSPA12A Is a Novel Player in Nonalcoholic Steatohepatitis via Promoting Nuclear PKM2-Mediated M1 Macrophage Polarization

Nonalcoholic steatohepatitis (NASH) is the most prevalent cause of chronic liver disease worldwide. Macrophage-mediated inflammation plays a critical role in NASH pathogenesis; however, optimum therapies for macrophage activation and NASH remain elusive. HSPA12A encodes a novel member of the HSP70 family. Here, we report that NASH patients showed increased hepatic HSPA12A expression and serum HSPA12A contents. Intriguingly, knockout of HSPA12A (Hspa12a-/- ) in mice attenuated high-fat diet (HFD)-induced hepatic steatosis and injury. HFD-induced macrophage polarization toward an M1 phenotype and inflammatory responses in the liver of Hspa12a-/- mice were also attenuated. Loss- and gain-of-function studies revealed that the de novo lipogenesis in hepatocytes was regulated by the paracrine effects of macrophage HSPA12A rather than by hepatocyte HSPA12A. In-depth molecular analysis revealed that HSPA12A interacted with the M2 isoform of pyruvate kinase (PKM2) in macrophages and increased its nuclear translocation, thereby promoting M1 polarization and secretion of proinflammatory M1 cytokines; this led, ultimately, to hepatocyte steatosis via paracrine effects. Taken together, these findings show that HSPA12A acts as a novel regulator of M1 macrophage polarization and NASH pathogenesis by increasing nuclear PKM2. Strategies that inhibit macrophage HSPA12A might be a potential therapeutic intervention for NASH.

Dragon's Blood exerts cardio-protection against myocardial injury through PI3K-AKT-mTOR signaling pathway in acute myocardial infarction mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Dragon's Blood (DB), the red resin of Dracaena cochinchinensis (Lour.) S. C., has been used in traditional Chinese medicine to treat acute myocardial infarction (AMI) for centuries. Evidence indicated that DB may exert cardio-protective effect by inhibiting inflammatory response during myocardial infarction. However, its pharmaceutical mechanism is still to be elucidated.

AIM OF THE STUDY

Due to its potential anti-inflammatory effect, Dragon's Blood extract (DBE) was applied on AMI mice model in this study and its mechanism on inflammation via PI3K-AKT-mTOR signaling pathway was to be validated.

MATERIALS AND METHODS

AMI mice model was established by ligation of left anterior descending (LAD) arteries. DBE was administered for 7 days before the surgery. Heart function was evaluated by 2D echocardiography. Levels of CK-MB and LDH1 in serum as well as TXB2, 6-keto-PGF1α and ET-1 in plasma were detected. Level of IL-6 in cardiac tissues was quantified by ELISA. Expressions of key proteins in PI3K-AKT-mTOR signaling pathway were detected by Western blot.

RESULTS

The result demonstrated that DBE could improve heart function in AMI mice model. Meanwhile, it could also regulate levels of CK-MB and LDH1, and restore balance between TXB2 and 6-keto-PGF1α. Further study suggested that DBE could inhibit inflammation and regulate expressions of key proteins in IL-6-JAK2/STAT3 pathway in cardiac tissue. Western blot results validated that DBE could activate PI3K-AKT-mTOR signaling pathway, thereby regulating the expressions of its downstream targets, including VEGF, COX2 and PPARγ.

CONCLUSION

DBE exerts cardio-protective efficacy by activating JAK2-STAT3 and PI3K-AKT-mTOR pathways in cardiac tissue. These findings provide insight into the pharmacological mechanism of DBE and validate the beneficial effects of DBE in the clinical application for AMI.

The role of Wnt signaling in the healing myocardium: a focus on cell specificity

Various cell types are involved in the healing process after myocardial infarction (MI). Besides cardiac resident cells (such as cardiomyocytes, fibroblasts and endothelial cells) already present at the lesion site, a massive influx of leukocytes (mainly monocytes and neutrophils) is observed within hours after the ischemic event. So far, little is known about modes of interaction of these cells. Wnt signaling is an evolutionary conserved signaling cassette known to play an important role in cell-cell communication. While the overall reactivation of Wnt signaling upon ischemic injury is well described, the precise expression pattern of Wnt proteins, however, is far from understood. We here describe known Wnt components that partake in MI healing and differentiate cell-specific aspects. The secretion of Wnt proteins and their antagonists in the context of cardiac inflammation after MI appear to be tightly regulated in a spatial-temporal manner. Overall, we aim to stress the importance of elucidating not only Wnt component-specific aspects, but also their sometimes contradicting effects in different target cells. A better understanding of Wnt signaling in MI healing may eventually lead to the development of successful therapeutic approaches in an often considered "un-druggable" pathway.

Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases

Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.

HSPA12B promotes functional recovery after ischaemic stroke through an eNOS-dependent mechanism

Stroke is the leading cause of disability worldwide. HSPA12B, a heat-shock protein recently identified expression specifically in endothelial cells, is able to promote angiogenesis. Here, we have investigated its effects on functional recovery at chronic phase of ischaemic stroke. Ischaemic stroke was induced by 60 min. of middle cerebral artery occlusion in transgenic mice with overexpression of HSPA12B (HSPA12B Tg) and wild-type littermates (WT). HSPA12B Tg mice demonstrated a significant higher survival rate than WT mice within 28 days post-stroke. Significant improved neurological functions, increased spontaneous locomotor activity and decreased anxiety were detected inHSPA12B Tg mice compared with WT controls within 21 days post-stroke. Stroke-induced hippocampal degeneration was attenuated in HSPA12B Tg mice examined at day 28 post-stroke. Interestingly, HSPA12B Tg mice showed enhanced peri-infarct angiogenesis (examined 28 days post-stroke) and hippocampal neurogenesis (examined 7 days post-stroke), respectively, compared to WT mice. The stroke-induced eNOS phosphorylation and TGF-β1 expression were augmented in HSPA12B Tg mice. However, administration with eNOS inhibitor L-NAME diminished the HSPA12B-induced protection in neurological functional recovery and mice survival post-stroke. The data suggest that HSPA12B promoted functional recovery and survival after stroke in an eNOS-dependent mechanism. Targeting HSPA12B expression may have a therapeutic potential for the stroke-evoked functional disability and mortality.

An in vitro endothelial cell protective effect of secretory leukocyte protease inhibitor against simulated ischaemia/reperfusion injury

Endothelial dysfunction is an essential deleterious modulator of ischaemia/reperfusion (I/R) injury. Secretory leukocyte protease inhibitor (SLPI) has demonstrated myocardial protection in cardiac transplantation; however, the effect of SLPI in endothelial I/R injury remains unexplored. In the present study, the effect of recombinant human SLPI (rhSLPI) treatment against endothelial cells (ECs) subjected to simulated I/R injury and the effect of treatment at different time points were determined. Human umbilical vein ECs (HUVECs) were subjected to normoxic or simulated I/R (sI/R) conditions, and rhSLPI at concentrations of 1, 10, 100 and 1,000 ng/ml was added to the cells prior to ischaemia, during ischaemia or at the onset of reperfusion. Endothelial injury and cytoskeleton disruption were assessed, and western blot analysis was conducted. The results revealed that rhSLPI treatment at 1,000 ng/ml significantly increased the HUVEC viability under sI/R injury (P<0.05). In addition, treatment with rhSLPI prior to or during ischaemia markedly attenuated the activity of lactase dehydrogenase compared with that in the sI/R group. In addition, the H₂O₂-induced reactive oxygen species production was reduced by ~17% upon rhSLPI pretreatment. Endothelial cytoskeleton disruption was also preserved by rhSLPI added prior to the reperfusion period. Furthermore, pretreatment with rhSLPI promoted protein kinase B activation, as well as reduced p38 mitogen-activated protein kinase phosphorylation and B-cell lymphoma 2-associated X protein expression in response to I/R injury. These findings indicated that rhSLPI possesses antioxidant and antiapoptotic properties against endothelial responses to I/R injury. Therefore, the cytoprotective effect of rhSLPI may provide a potential pharmaceutical target to limit endothelial-mediated I/R injury.

Isoflurane Preconditioning Alleviated Murine Liver Ischemia and Reperfusion Injury by Restoring AMPK/mTOR-Mediated Autophagy

BACKGROUND

Isoflurane has a pharmacological preconditioning effect against ischemia injury in the heart, kidney, and brain, but whether and how isoflurane preconditioning protects livers against ischemia and reperfusion (IR) injury is unclear.

METHODS

Mice were randomly divided into an isoflurane preconditioning (ISO) group and control group, receiving 1.5% isoflurane or carrier gas for 40 minutes, respectively (n = 8/group). A partial warm liver IR model was used, and liver injury was evaluated. Primary hepatocytes were pretreated with 1.5% isoflurane for 2 hours before the induction of cell death by hydrogen peroxide. Cell death and survival were evaluated with the lactate dehydrogenase and cell counting kit-8 assay. Autophagy and regulatory molecules in stressed livers and hepatocytes were analyzed by Western blot (n = 6/group). An autophagy inhibitor (3-methyladenine [3-MA]) and 5' adenosine monophosphate-activated protein kinase (AMPK) inhibitor (dorsomorphin) were administered in vivo (n = 8/group) and in vitro (n = 6/group).

RESULTS

Compared to that observed in the control group, mice in the ISO group showed reduced liver injury (alanine aminotransferase [ALT] levels, control versus ISO group, 8285 ± 769 vs 4896 ± 917 U/L, P < .001) and enhanced hepatocellular antiapoptosis in livers after IR. Furthermore, liver autophagy was restored by ISO as indicated by elevated LC3B II protein levels accompanied with increased p62 degradation. The in vitro study of primary hepatocytes also found that ISO effectively attenuated hepatocyte cell death induced by hydrogen peroxide. In addition, 3-MA pretreatment showed no significant influence in the control group, but abrogated the protective role of ISO both in stressed livers (ALT levels, phosphate-buffered saline + ISO versus 3-MA + ISO group, 5081 ± 294 vs 8663 ± 607 U/L, P < .001) and in hepatocytes. Finally, signaling pathway analysis demonstrated that AMPK was activated by ISO. Pretreatment with an AMPK inhibitor also abrogated liver protection by ISO (ALT levels, phosphate-buffered saline + ISO versus dorsomorphin [DOR] + ISO group, 5081 ± 294 vs 8710 ± 500 U/L, P < .001), with no significant effect in control mice.

CONCLUSIONS

Our results indicate that isoflurane preconditioning attenuates liver IR injury via AMPK/mTOR-mediated hepatocellular autophagy restoration. Our findings provide a novel potential therapeutic strategy for managing liver IR injury.

Crude terpene glycoside component from Radix paeoniae rubra protects against isoproterenol-induced myocardial ischemic injury via activation of the PI3K/AKT/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Radix paeoniae rubra, also known as chishao (CS), is a frequently used traditional Chinese medicine that can promote blood circulation to remove blood stasis. It has been widely used for the prevention and treatment of cardiovascular diseases in China. Although terpene glycoside (TG), the major component in CS, has been shown to possess cardioprotective properties, the mechanism underlying CS-TG's preventive effect against myocardial ischemia injury is unknown. This study was conducted to explore the protective and curative effects of CS-TG against isoproterenol (ISO)-induced myocardial ischemic injury in rats and investigate the underlying myocardial protective mechanisms.

MATERIALS AND METHODS

A rat model of ISO-induced myocardial ischemia was established to evaluate the protective effect of CS-TG in ameliorating heart injury. Myocardial ischemia was induced by administering ISO (40mg/kg/d) subcutaneously for 2 days. Serum was collected and analyzed for the levels of different cardiac biomarkers, and heart tissues were isolated and prepared for ATP analysis, glycogen content determination, histopathology assay, and ultrastructure observation. The regulatory effects of CS-TG on myocardial apoptosis in rats were studied by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, and the levels of cleaved caspase-3, Bax, and Bcl-2 were detected by western blotting. Furthermore, in vitro experiments were conducted to examine whether the CS-TG's cardioprotective effects were linked to the inhibition of apoptosis via activation of the phosphoinositide-3-kinase/serine-threonine kinase AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway.

RESULTS

CS-TG (300mg/kg/d) significantly decreased serum levels of creatine kinase and lactate dehydrogenase in ISO-induced myocardial ischemic rats. Analysis of ATP and glycogen contents, myocardial ultrastructure, and pathological examination showed that CS-TG (300mg/kg/d) significantly improved energy metabolism and alleviated myocardial injury in vivo. In addition, the expression of p-AKT and p-mTOR in rats subjected to CS-TG significantly elevated, while the levels of caspase-3 and Bax/Bcl-2 dramatically reduced. Moreover, treatment with LY294002, a PI3K inhibitor, abrogated CS-TG (200μg/mL) induced down-regulation of cleaved caspase-3, Bax/Bcl-2 in the serum.

CONCLUSIONS

CS-TG protects the heart from ISO-induced myocardial ischemia, potentially by improving cardiac energy metabolism and inhibiting cardiomyocyte apoptosis via activation of the PI3K/AKT/mTOR signaling pathway. Thus, CS -TG might be a potential therapeutic candidate for the prevention and treatment of myocardial ischemia.

Therapeutic Effects of Breviscapine in Cardiovascular Diseases: A Review

Breviscapine is a crude extract of several flavonoids of Erigeron breviscapus (Vant.) Hand.-Mazz., containing more than 85% of scutellarin, which has been traditionally used in China as an activating blood circulation medicine to improve cerebral blood supply. Accumulating evidence from various in vivo and in vitro studies has shown that breviscapine exerts a broad range of cardiovascular pharmacological effects, including vasodilation, protection against ischaemia/reperfusion (I/R), anti-inflammation, anticoagulation, antithrombosis, endothelial protection, myocardial protection, reduction of smooth muscle cell migration and proliferation, anticardiac remodeling, antiarrhythmia, blood lipid reduction, and improvement of erectile dysfunction. In addition, several clinical studies have reported that breviscapine could be used in conjunction with Western medicine for cardiovascular diseases (CVDs) including coronary heart disease, myocardial infarction, hypertension, atrial fibrillation, hyperlipidaemia, viral myocarditis, chronic heart failure, and pulmonary heart disease. However, the protective effects of breviscapine on CVDs based on experimental studies along with its underlying mechanisms have not been reviewed systematically. This paper reviewed the underlying pharmacological mechanisms in the cardioprotective effects of breviscapine and elucidated its clinical applications.

Myricitrin Alleviates Oxidative Stress-induced Inflammation and Apoptosis and Protects Mice against Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) has been increasingly considered as a main cause of heart failure and death in diabetic patients. At present, no effective treatment exists to prevent its development. In the present study, we describe the potential protective effects and mechanisms of myricitrin (Myr) on the cardiac function of streptozotosin-induced diabetic mice and on advanced glycation end products (AGEs)-induced H9c2 cardiomyocytes. In vitro experiments revealed that pretreatment with Myr significantly decreased AGEs-induced inflammatory cytokine expression, limited an increase in ROS levels, and reduced cell apoptosis, fibrosis, and hypertrophy in H9c2 cells. These effects are correlated with Nrf2 activation and NF-κB inhibition. In vivo investigation demonstrated that oral administration of Myr at 300 mg/kg/day for 8 weeks remarkably decreased the expression of enzymes associated with cardiomyopathy, as well as the expression of inflammatory cytokines and apoptotic proteins. Finally, Myr improved diastolic dysfunction and attenuated histological abnormalities. Mechanistically, Myr attenuated diabetes-induced Nrf2 inhibition via the regulation of Akt and ERK phosphorylation in the diabetic heart. Collectively, these results strongly indicate that Myr exerts cardioprotective effects against DCM through the blockage of inflammation, oxidative stress, and apoptosis. This suggests that Myr might be a potential therapeutic agent for the treatment of DCM.