Sevoflurane blocks KLF5-mediated transcriptional activation of ITGB2 to inhibit macrophage infiltration in hepatic ischemia/reperfusion injury.

BACKGROUND: Sevoflurane (Sevo) preconditioning and postconditioning play a protective role against injury induced by hepatic ischemia/reperfusion (I/R). At the same time, the involvement of macrophage infiltration in this process and the precise mechanisms are unclear. Here, we designed this research to elucidate the protective effects of Sevo against hepatic I/R injury and the molecules involved. METHODS: The alleviating effect of Sevo on the liver injury was analyzed by liver function analysis, hematoxylin and eosin staining, Masson trichrome staining, terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling, western blot analysis and an enzyme-linked immunosorbent assay. An in vitro cell model was developed using alpha mouse liver 12 (AML12) cells, and the cell model was treated with oxygen-glucose deprivation and reoxygenation and Sevo. Multiple bioinformatics databases were used to screen transcriptional regulators related to hepatic I/R injury and the targets of Krueppel-like factor 5 (KLF5). KLF5 expression was artificially upregulated alone or with integrin beta-2 (ITGB2) knockdown to substantiate their involvement in Sevo-mediated hepatoprotection. RESULTS: Sevo protected the liver against I/R injury by reducing cell apoptosis and inflammatory response. KLF5 was upregulated in liver tissues following I/R injury, whereas KLF5 overexpression aggravated macrophage infiltration and liver injury induced by I/R injury. KLF5 bound to the promoter of ITGB2 to enhance ITGB2 transcription. Knockdown of ITGB2 reversed the aggravation of injury caused by KLF5 overexpression in mice and AML12 cells. CONCLUSIONS: Sevo blocked KLF5-mediated transcriptional activation of ITGB2, thereby inhibiting macrophage infiltration in hepatic I/R injury.

Mycn ameliorates cardiac hypertrophy-induced heart failure in mice by mediating the USP2/JUP/Akt/ß-catenin cascade.

BACKGROUND: Pathological cardiac hypertrophy is associated with cardiac dysfunction and is a key risk factor for heart failure and even sudden death. This study investigates the function of Mycn in cardiac hypertrophy and explores the interacting molecules. METHODS: A mouse model of cardiac hypertrophy was induced by isoproterenol (ISO). The cardiac dysfunction was assessed by the heart weight-to-body weight ratio (HW/BW), echocardiography assessment, pathological staining, biomarker detection, and cell apoptosis. Transcriptome alteration in cardiac hypertrophy was analyzed by bioinformatics analysis. Gain- or loss-of-function studies of MYCN proto-oncogene (Mycn), ubiquitin specific peptidase 2 (USP2), and junction plakoglobin (JUP) were performed. The biological functions of Mycn were further examined in ISO-treated cardiomyocytes. The molecular interactions were verified by luciferase assay or immunoprecipitation assays. RESULTS: Mycn was poorly expressed in ISO-treated mice, and its upregulation reduced HW/BW, cell surface area, oxidative stress, and inflammation while improving cardiac function of mice. It also reduced apoptosis of cardiomyocytes in mice and those in vitro induced by ISO. Mycn bound to the USP2 promoter to activate its transcription. USP2 overexpression exerted similar myocardial protective functions. It stabilized JUP protein by deubiquitination modification, which blocked the Akt/ß-catenin pathway. Knockdown of JUP restored phosphorylation of Akt and ß-catenin protein level, which negated the protective effects of USP2. CONCLUSION: This study demonstrates that Mycn activates USP2 transcription, which mediates ubiquitination and protein stabilization of JUP, thus inactivating the Akt/ß-catenin axis and alleviating cardiac hypertrophy-induced heart failure.

EZH2 mitigates the cardioprotective effects of mesenchymal stem cell-secreted exosomes against infarction via HMGA2-mediated PI3K/AKT signaling.

BACKGROUND: Mesenchymal stem cell-derived exosomes (MSC-EXO) have emerged as novel therapeutic strategies for myocardial infarction (MI). However, many questions remain untouched and unanswered regarding their roles in myocardial fibrosis. This study aimed to probe the therapeutic effects of MSC-EXO on myocardial fibrosis after MI and possible mechanisms. METHODS: Myocardial tissues were obtained from MI rats, and myocardial cell viability, fibrosis, apoptosis, and epithelial-mesenchymal transition (EMT) were detected by immunohistochemistry, Masson's staining, TUNEL, and western blot. Bone marrow-derived MSCs and corresponding EXO were identified, and cardiac function were detected after treatment of MSC-EXO. Bioinformatics analysis and ChIP assay were conducted to detect the downstream genes of EZH2. EZH2 was upregulated alone or with HMGA2 overexpression in myocardial tissues of MI rats upon MSC-EXO treatment, and PI3K/AKT pathway activity in myocardial tissues was detected using western blot. RESULTS: The proliferative activity in myocardial tissues of MI rats was significantly decreased, along with accentuated fibrosis, increased collagen volume and EMT. MSC-EXO treatment resulted in partial restoration of cardiac function and reduced EZH2 expression in the myocardium of rats. EZH2 inhibited HMGA2 expression by increasing the H3K27me3 modification. PI3K/AKT pathway was altered under the influence of the EZH2/HMGA2 axis. EZH2 inhibited the effect of MSC-EXO on the recovery of cardiac function and accelerated fibrosis, while HMGA2 reversed the effect of EZH2 to reduce fibrosis and enhance cardiac function. CONCLUSION: MSC-EXO alleviated fibrosis in MI rats via inhibition of EZH2, whereas EZH2 inhibited HMGA2 expression and impaired the PI3K/AKT pathway.

GPR39 promotes cardiac hypertrophy by regulating the AMPK-mTOR pathway and protein synthesis.

Hypertrophic growth of the cardiomyocytes is one of the core mechanisms underlying cardiac hypertrophy. However, the mechanism underlying cardiac hypertrophy remains not fully understood. Here we provided evidence that G protein-coupled receptor 39 (GPR39) promotes cardiac hypertrophy via inhibiting AMP-activated protein kinase (AMPK) signaling. GRP39 expression is overexpressed in hypertrophic hearts of humans and transverse aortic constriction (TAC)-induced cardiac hypertrophy in mice. In neonatal cardiomyocytes, adenovirus-mediated overexpression of GPR39 promoted angiotensin II-induced cardiac hypertrophy, while GPR39 knockdown repressed hypertrophic response. Adeno-associated virus 9-mediated knockdown of GPR39 suppressed TAC-induced decline in fraction shortening and ejection fraction, increase in heart weight and cardiomyocyte size, as well as overexpression of hypertrophic fetal genes. A mechanism study demonstrated that GPR39 repressed the activation of AMPK to activate the mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase ß-1 (S6K1), subsequently promoted de novo protein synthesis. Inhibition of mTOR with rapamycin blocked the effects of GPR39 overexpression on protein synthesis and repressed cardiac hypertrophy. Collectively, our findings demonstrated that GPR39 promoted cardiac hypertrophy via regulating the AMPK-mTOR-S6K1 signaling pathway, and GRP39 can be targeted for the treatment of cardiac hypertrophy.

KLK11 promotes the activation of mTOR and protein synthesis to facilitate cardiac hypertrophy.

BACKGROUND: Cardiovascular diseases have become the leading cause of death worldwide, and cardiac hypertrophy is the core mechanism underlying cardiac defect and heart failure. However, the underlying mechanisms of cardiac hypertrophy are not fully understood. Here we investigated the roles of Kallikrein 11 (KLK11) in cardiac hypertrophy. METHODS: Human and mouse hypertrophic heart tissues were used to determine the expression of KLK11 with quantitative real-time PCR and western blot. Mouse cardiac hypertrophy was induced by transverse aortic constriction (TAC), and cardiomyocyte hypertrophy was induced by angiotensin II. Cardiac function was analyzed by echocardiography. The signaling pathway was analyzed by western blot. Protein synthesis was monitored by the incorporation of [3H]-leucine. Gene expression was analyzed by quantitative real-time PCR. RESULTS: The mRNA and protein levels of KLK11 were upregulated in human hypertrophic hearts. We also induced cardiac hypertrophy in mice and observed the upregulation of KLK11 in hypertrophic hearts. Our in vitro experiments demonstrated that KLK11 overexpression promoted whereas KLK11 knockdown repressed cardiomyocytes hypertrophy induced by angiotensin II, as evidenced by cardiomyocyte size and the expression of hypertrophy-related fetal genes. Besides, we knocked down KLK11 expression in mouse hearts with adeno-associated virus 9. Knockdown of KLK11 in mouse hearts inhibited TAC-induced decline in fraction shortening and ejection fraction, reduced the increase in heart weight, cardiomyocyte size, and expression of hypertrophic fetal genes. We also observed that KLK11 promoted protein synthesis, the key feature of cardiomyocyte hypertrophy, by regulating the pivotal machines S6K1 and 4EBP1. Mechanism study demonstrated that KLK11 promoted the activation of AKT-mTOR signaling to promote S6K1 and 4EBP1 pathway and protein synthesis. Repression of mTOR with rapamycin blocked the effects of KLK11 on S6K1 and 4EBP1 as well as protein synthesis. Besides, rapamycin treatment blocked the roles of KLK11 in the regulation of cardiomyocyte hypertrophy. CONCLUSIONS: Our findings demonstrated that KLK11 promoted cardiomyocyte hypertrophy by activating AKT-mTOR signaling to promote protein synthesis.

FBXW7 promotes pathological cardiac hypertrophy by targeting EZH2-SIX1 signaling.

F-box and WD repeat domain-containing 7 (FBXW7) is an E3-ubiquitin ligase, which serves as one of the components of the SKP1, CUL1, and F-box protein type ubiquitin ligase (SCF) complex. Previous studies reveal that FBXW7 participates in cancer, inflammation and Parkinson's disease. FBXW7 also contributes to angiogenesis of endothelial cells. However, the function of FBXW7 in cardiac homeostasis remains to elucidate. Here we identified the critical role of FBXW7 during cardiac hypertrophy in humans and rodents. Quantitative real-time PCR (qRT-PCR) and Western blot revealed that the mRNA and protein levels of FBXW7 were upregulated significantly in hypertrophic hearts in human and mouse as well as Angiotensin II (Ang II)-induced hypertrophic neonatal rat cardiomyocytes (NRCM). Gain-of-function (adenovirus) and loss-of-function (siRNA) experiments provided evidence that FBXW7 promoted Ang II-induced cardiomyocyte hypertrophy as demonstrated by the increase in the size of cardiomyocytes and overexpression of hypertrophic fetal genes myosin heavy chain 7 (Myh7) natriuretic peptide a (Nppa), brain natriuretic peptide (Nppb). Further mechanism study revealed that FBXW7 promoted the expression of sine oculis homeobox homolog 1 (SIX1) in cardiomyocytes, which relied on regulation of the stability of the histone methyltransferase EZH2 (Enhancer of zeste homolog 2). Previous work revealed the pro-hypertrophic role of the EZH2-SIX1 axis in rodents. Indeed, our genetic and pharmacological evidence showed that the EZH2-SIX1 signaling was critically involved in FBXW7 functions in Ang II-induced cardiomyocyte hypertrophy. Therefore, we identified FBWX7 as an important regulator of cardiac hypertrophy via modulating the EZH2-SIX1 axis.

Mesenchymal stem cells-derived extracellular vesicle-incorporated H19 attenuates cardiac remodeling in rats with heart failure.

Cardiac remodeling is manifested by hypertrophy and apoptosis of cardiomyocytes, resulting in the progression of cardiovascular diseases. Long noncoding RNAs (lncRNAs) serve as modifiers of cardiac remodeling. In this study, we aimed to explore the molecular mechanism of H19 shuttled by mesenchymal stem cells (MSC)-derived extracellular vesicles (EV) in cardiac remodeling upon heart failure (HF). Using the GEO database, H19, microRNA (miR)-29b-3p, and CDC42 were screened out as differentially expressed biomolecules in HF. H19 and CDC42 were elevated, and miR-29b-3p was decreased after MSC-EV treatment in rats subjected to ligation of the coronary artery. MSC-EV alleviated myocardial injury in rats with HF. H19 downregulation exacerbated myocardial injury, while miR-29b-3p inhibitor alleviated myocardial injury. By contrast, CDC42 downregulation aggravated the myocardial injury again. PI3K/AKT pathway was activated by MSC-EV. These findings provide insights into how H19 shuttled by EV mitigates cardiac remodeling through a competitive endogenous RNA network regarding miR-29b-3p and CDC42.

ANP32B promotes lung cancer progression by regulating VDAC1.

It has been reported before that acidic leucine-rich nuclear phosphoprotein 32 family member B (ANP32B) plays roles in many cancers, yet no report of its role in lung cancer exists. In this study, we documented an elevation of ANP32B within lung cancer tissues and cells. Knockdown of ANP32B hindered the proliferation as well as migration of lung cancer cells, whereas overexpression of ANP32B helps to promote the malignant progression of lung cancer. ANP32B also regulates lung cancer cells' apoptosis and cell cycling. In addition, voltage-dependent anion channel 1 (VDAC1) has been found to be a downstream targeted gene of ANP32B and is positively regulated by ANP32B in lung cancer cells. According to our research, the expression of VDAC1 was positively associated with ANP32B expression in lung adenocarcinoma (r = 0.61, P < 0.001) samples by Pearson's correlation coefficient analysis. Furthermore, rescue experiments demonstrated that VDAC1 could rescue the effect of ANP32B expression on lung cancer cell proliferation and migration. Our results suggest that ANP32B overexpression facilitates lung cancer progression by increasing the expression of VDAC1. As such, we have revealed a novel mechanism regulating the connection between ANP32B and VDAC1 and a potential role of ANP32B as an oncogene and a clinical therapeutic target in lung cancer.

GM-CSF-mediated inducement of bone marrow MDSCs by TSA and effect on survival of graft in mice.

OBJECTIVE: This study analyzed the effect of HDAC inhibitor, trichostatin A (TSA), in inducing granulocyte-macrophage colony-stimulating factor (GM-CSF)-mediated bone marrow (BM) cell differentiation to myeloid-derived suppressor cells (MDSCs) in vitro and in vivo. METHODS: BM cell differentiation to CD11b + GR-1 + MDSCs was achieved by in vitro culture with TSA and GM-CSF, and the collected cells were analyzed by mixed lymphocyte culture to identify suppressive actions against effector T cells. RT-PCR and ELISA were conducted to analyze the CCL5 mRNA and protein levels in TSA + GM-CSF + BM, GR-1 + MDSCs and GR-1 + MDSC + CCL5 groups. The survival of cardiac grafts was compared between groups. RESULTS: TSA was beneficial for the GM-CSF-mediated BM differentiation to CD11b + GR-1 + MDSCs. Adoptive transfer of GR-1 + MDSCs was powerful in suppressing CD4 + CD25-T cell proliferation and the effect was mediated by iNOS and HO-1; it also increased CCL5 gradient concentration between grafts and plasma to recruit Treg to grafts and prolong the survival of the grafts. Survival analysis revealed that the survival of grafts after adoptive transfer of GR-1 + MDSCs could be prolonged. CONCLUSION: This study helps in further research on the application value of MDSCs in the field of transplant, and may provide a new thought for the cell therapy in inducing immune tolerance in organ transplant.

Kruppel like factor 16 promotes lung adenocarcinoma progression by upregulating lamin B2.

Lung cancer is one of the most common causes of cancer-related death. In the past decade, the treatment and diagnosis of lung cancer have progressed significantly in early efforts to promote the survival of lung cancer patients. Kruppel like factor 16 (KLF16) is a zinc finger transcription factor that regulates a diverse array of developmental events and cellular processes. KLF16 is involved in the progression of various cancer types. However, the role of KLF16 in the development of lung cancer remains unknown. In this study, KLF16 was overexpressed in lung cancer samples. KLF16 downregulation inhibited lung cancer cell proliferation and migration. Conversely, KLF16 overexpression promoted lung cancer cell growth and invasion. Mechanistically, the expression level LMNB2 was suppressed by KLF16 knockdown and was promoted by KLF16 overexpression. The overall survival of patients with high LMNB2 levels was poor. Luciferase assays showed that KLF16 promoted the transcription activity of LMNB2 gene. Concomitantly, the expression level of LMNB2 was also higher in lung adenocarcinoma (LUAD) than in normal tissues, and its knockdown or overexpression can reverse the effect of KLF16 overexpression or knockdown on lung cancer cell proliferation, migration, and even tumorigenesis, indicating that LMNB2 also functions as an oncogene. In conclusion, KLF16 can be used as a potential therapeutic and preventive biomarker in lung cancer treatment and prognosis by actively regulating the expression of LMNB2.

HTR2A promotes the development of cardiac hypertrophy by activating PI3K-PDK1-AKT-mTOR signaling.

5-Hydroxytryptamine receptor 2A (HTR2A) is a central regulator of fetal brain development and cognitive function in adults. However, the roles of HTR2A in the cardiovascular system are not fully understood. Here in this study, we explored the function of HTR2A in cardiac hypertrophy. Significantly, the expression levels of HTR2A mRNA and protein levels were upregulated in hypertrophic hearts of human patients. Besides, the expression of HTR2A was also upregulated in isoproterenol (ISO)-induced cardiac hypertrophy in the mouse. Next, the expression of HTR2A was knocked down with shRNA or overexpressed with adenovirus in neonatal rat cardiomyocytes, and ISO was used to induce cardiomyocyte hypertrophy. We showed that HTR2A knockdown repressed ISO-induced cardiomyocyte hypertrophy, which was demonstrated by decreased cardiomyocyte size and repressed expression of hypertrophic fetal genes (e.g., myosin heavy chain beta (ß-Mhc), atrial natriuretic peptide (Anp), and brain natriuretic peptide (Bnp)). By contrast, HTR2A overexpression promoted cardiomyocyte hypertrophy. Of note, we observed that HTR2A promoted the activation (phosphorylation) of AKT-mTOR (mammalian target of rapamycin) signaling in cardiomyocytes, and repression of AKT-mTOR with perifosine or rapamycin blocked the effects of HTR2A on cardiomyocyte hypertrophy. Finally, we showed that HTR2A regulated AKT-mTOR signaling through activating the PI3K-PDK1 pathway, and inhibition of either PI3K or PDK1 blocked the roles of HTR2A in regulating AKT-mTOR signaling and cardiomyocyte hypertrophy. Altogether, these findings demonstrated that HTR2A activated PI3K-PDK1-AKT-mTOR signaling and promoted cardiac hypertrophy.

Carboxypeptidase A4 promotes cardiomyocyte hypertrophy through activating PI3K-AKT-mTOR signaling.

Carboxypeptidase A4 (CPA4) is a member of the metallocarboxypeptidase family. Current studies have identified the roles of CPA4 in cancer biology and insulin sensitivity. However, the roles of CPA4 in other diseases are not known. In the present study, we investigated the roles of CPA4 in cardiac hypertrophy. The expression of CPA4 was significantly increased in the hypertrophic heart tissues of human patients and isoproterenol (ISO)-induced hypertrophic heart tissues of mice. We next knocked down Cpa4 with shRNA or overexpressed Cpa4 using adenovirus in neonatal rat cardiomyocytes and induced cardiomyocyte hypertrophy with ISO. We observed that Cpa4 overexpression promoted whereas Cpa4 knockdown reduced ISO-induced growth of cardiomyocyte size and overexpression of hypertrophy marker genes, such as myosin heavy chain ß (ß-Mhc), atrial natriuretic peptide (Anp), and brain natriuretic peptide (Bnp). Our further mechanism study revealed that the mammalian target of rapamycin (mTOR) signaling was activated by Cpa4 in cardiomyocytes, which depended on the phosphoinositide 3-kinase (PI3K)-AKT signaling. Besides, we showed that the PI3K-AKT-mTOR signaling was critically involved in the roles of Cpa4 during cardiomyocyte hypertrophy. Collectively, these results demonstrated that CPA4 is a regulator of cardiac hypertrophy by activating the PI3K-AKT-mTOR signaling, and CPA4 may serve as a promising target for the treatment of hypertrophic cardiac diseases.