Epigenetic Regulation in Myocardial Fibroblasts and Its Impact on Cardiovascular Diseases.

Myocardial fibroblasts play a crucial role in heart structure and function. In recent years, significant progress has been made in understanding the epigenetic regulation of myocardial fibroblasts, which is essential for cardiac development, homeostasis, and disease progression. In healthy hearts, cardiac fibroblasts (CFs) play a crucial role in synthesizing the extracellular matrix (ECM) when in a dormant state. However, under pathological and environmental stress, CFs transform into activated fibroblasts known as myofibroblasts. These myofibroblasts produce an excess of ECM, which promotes cardiac fibrosis. Although multiple molecular mechanisms are associated with CF activation and myocardial dysfunction, emerging evidence highlights the significant involvement of epigenetic regulation in this process. Epigenetics refers to the heritable changes in gene expression that occur without altering the DNA sequence. These mechanisms have emerged as key regulators of myocardial fibroblast function. This review focuses on recent advancements in the understanding of the role of epigenetic regulation and emphasizes the impact of epigenetic modifications on CF activation. Furthermore, we present perspectives and prospects for future research on epigenetic modifications and their implications for myocardial fibroblasts.

Design of eco-friendly antifreeze peptides as novel inhibitors of gas-hydration kinetics.

In this study, peptides designed using fragments of an antifreeze protein (AFP) from the freeze-tolerant insect Tenebrio molitor, TmAFP, were evaluated as inhibitors of clathrate hydrate formation. It was found that these peptides exhibit inhibitory effects by both direct and indirect mechanisms. The direct mechanism involves the displacement of methane molecules by hydrophobic methyl groups from threonine residues, preventing their diffusion to the hydrate surface. The indirect mechanism is characterized by the formation of cylindrical gas bubbles, the morphology of which reduces the pressure difference at the bubble interface, thereby slowing methane transport. The transfer of methane to the hydrate interface is primarily dominated by gas bubbles in the presence of antifreeze peptides. Spherical bubbles facilitate methane migration and potentially accelerate hydrate formation; conversely, the promotion of a cylindrical bubble morphology by two of the designed systems was found to mitigate this effect, leading to slower methane transport and reduced hydrate growth. These findings provide valuable guidance for the design of effective peptide-based inhibitors of natural-gas hydrate formation with potential applications in the energy and environmental sectors.

Histone deacetylase complexes: Structure, regulation and function.

Histone deacetylases (HDACs) are key epigenetic regulators, and transcriptional complexes with deacetylase function are among the epigenetic corepressor complexes in the nucleus that target the epigenome. HDAC-bearing corepressor complexes such as the Sin3 complex, NuRD complex, CoREST complex, and SMRT/NCoR complex are common in biological systems. These complexes activate the otherwise inactive HDACs in a solitary state. HDAC complexes play vital roles in the regulation of key biological processes such as transcription, replication, and DNA repair. Moreover, deregulated HDAC complex function is implicated in human diseases including cancer. Therapeutic strategies targeting HDAC complexes are being sought actively. Thus, illustration of the nature and composition of HDAC complexes is vital to understanding the molecular basis of their functions under physiologic and pathologic conditions, and for designing targeted therapies. This review presents key aspects of large multiprotein HDAC-bearing complexes including their structure, function, regulatory mechanisms, implication in disease development, and role in therapeutics.

Morphological and molecular data reveal Cerrenacaulinicystidiata sp. nov. and Polyporusminutissimus sp. nov. in Polyporales from Asia.

Two new species of Polyporales, Cerrenacaulinicystidiata and Polyporusminutissimus, are illustrated and described on the basis of morphological studies and phylogenetic analyses from southern China and Vietnam. C.caulinicystidiata is characterized by annual, resupinate, sometimes effused-reflexed basidiocarps, greyish orange to brownish orange pore surface, irregular pores (3-8 per mm), a trimitic hyphal system, pyriform to ventricose cystidia, and subglobose basidiospores 3.2-4.5 × 2.8-3.5 µm in size. P.minutissimus is characterized by annual, solitary, fan-shaped with a depressed center or infundibuliform basidiocarps, obvious black stipe, cream to buff yellow pileal surface with glabrous, occasionally zonate and radially aligned stripes, angular pores (6-9 per mm), a dimitic hyphal system, and cylindrical basidiospores, 5-9.2 × 2.2-4 µm. Detailed descriptions and illustrations of the two new species are provided. The differences between the two new species and their morphologically similar and phylogenetically related species are discussed.

Transcriptome-wide 1-methyladenosine functional profiling of messenger RNA and long non-coding RNA in bladder cancer.

Introduction: Post-transcriptional RNA modifications are crucial regulators of tumor development and progression. In many biological processes, N1-methyladenosine (m1A) plays a key role. However, little is known about the links between chemical modifications of messenger RNAs (mRNAs) and long noncoding RNAs (lncRNAs) and their function in bladder cancer (BLCA). Methods: Methylated RNA immunoprecipitation sequencing and RNA sequencing were performed to profile mRNA and lncRNA m1A methylation and expression in BLCA cells, with or without stable knockdown of the m1A methyltransferase tRNA methyltransferase 61A (TRMT61A). Results: The analysis of differentially methylated gene sites identified 16,941 peaks, 6,698 mRNAs, and 10,243 lncRNAs in the two groups. Gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the differentially methylated and expressed transcripts showed that m1A-regulated transcripts were mainly related to protein binding and signaling pathways in cancer. In addition, the differentially genes were identified that were also differentially m1A-modified and identified 14 mRNAs and 19 lncRNAs. Next, these mRNAs and lncRNAs were used to construct a lncRNA-microRNA-mRNA competing endogenous RNA network, which included 118 miRNAs, 15 lncRNAs, and 8 mRNAs. Finally, the m1A-modified transcripts, SCN2B and ENST00000536140, which are highly expressed in BLCA tissues, were associated with decreased overall patient survival. Discussion: This study revealed substantially different amounts and distributions of m1A in BLCA after TRMT61A knockdown and predicted cellular functions in which m1A may be involved, providing evidence that implicates m1A mRNA and lncRNA epitranscriptomic regulation in BLCA tumorigenesis and progression.

Magnetic resonance imaging of extraocular rectus muscles abnormalities in acute acquired concomitant esotropia.

AIM: To investigate the difference of medial rectus (MR) and lateral rectus (LR) between acute acquired concomitant esotropia (AACE) and the healthy controls (HCs) detected by magnetic resonance imaging (MRI). METHODS: A case-control study. Eighteen subjects with AACE and eighteen HCs were enrolled. MRI scanning data were conducted in target-controlled central gaze with a 3-Tesla magnetic resonance scanner. Extraocular muscles (EOMs) were scanned in contiguous image planes 2-mm thick spanning the EOM origins to the globe equator. To form posterior partial volumes (PPVs), the LR and MR cross-sections in the image planes 8, 10, 12, and 14 mm posterior to the globe were summed and multiplied by the 2-mm slice thickness. The data were classified according to the right eye, left eye, dominant eye, and non-dominant eye, and the differences in mean cross-sectional area, maximum cross-sectional area, and PPVs of the MR and LR muscle in the AACE group and HCs group were compared under the above classifications respectively. RESULTS: There were no significant differences between the two groups of demographic characteristics. The mean cross-sectional area of the LR muscle was significantly greater in the AACE group than that in the HCs group in the non-dominant eyes (P=0.028). The maximum cross-sectional area of the LR muscle both in the dominant and non-dominant eye of the AACE group was significantly greater than the HCs group (P=0.009, P=0.016). For the dominant eye, the PPVs of the LR muscle were significantly greater in the AACE than that in the HCs group (P=0.013), but not in the MR muscle (P=0.698). CONCLUSION: The size and volume of muscles dominant eyes of AACE subjects change significantly to overcome binocular diplopia. The LR muscle become larger to compensate for the enhanced convergence in the AACE.

LINC02561 promotes metastasis in HCC via HIF1-α/NDRG1/UPF1 axis.

In the entire world, hepatocellular carcinoma (HCC) is one of the most frequent cancers that lead to death. Experiments on the function of long non-coding RNAs in the emergence of malignancies, including HCC, are ongoing. As a crucial RNA monitoring mechanism in eucaryotic cells, nonsense-mediated mRNA decay (NMD) can recognize and destroy mRNAs, which has an premature termination codons (PTC) in the open reading frame to prevent harmful buildup of truncated protein products in the cells. Nonsense transcript regulator 1 (Up-frameshift suppressor 1, UPF1), as a highly conserved RNA helicase and ATPase, plays a key role in NMD. Our laboratory screened out the highly expressed lncRNA LINC02561 in HCC from the TCGA database. Further research found that LINC02561 enhanced the invasion and transition abilities of liver cancer cells by regulating the protein N-Myc downstream regulated 1 (NDRG1). Hypoxia inducible factor-1 (HIF-1α) can bonded to LINC02561 promoters under hypoxic conditions, thereby promoting the upregulation of LINC02561 expression in liver cancer cells. LINC02561 competes with NDRG1 mRNA to bind UPF1, thereby preventing the degradation of NDRG1 mRNA to facilitate NDRG1 protein level. Taken together, the HIF1α-LINC02561-UPF1-NDRG1 regulatory axis could be an entirely novel target of liver cancer-related treatment.

Synergistic Effect of Hyperactive Antifreeze Protein on Inhibition of Gas-Hydrate Growth by Hydrophobic and Hydrophilic Groups.

Antifreeze proteins (AFPs) are biodegradable inhibitors that effectively prevent the formation of natural gas hydrates that block pipelines. In this study, molecular dynamics simulations were employed to establish a kinetic model of the hyperactive insect antifreeze protein (Tenebrio molitor, TmAFP) and its mutants to inhibit the growth of sI natural methane hydrate. Simulations revealed that the hydrophobic and hydrophilic groups of threonine (Thr) residues at hydrate-binding sites played a synergistic role in binding hydrates. The hydrophobic groups anchored TmAFP to the hydrate surface through residues Thr39-Thr65 by migrating pendant hydrophobic methyl groups to the hydrate semicages. The hydrophilic groups stabilized TmAFP by hydrogen bonding with water molecules and integrating them into a quasi-hydrate structure, which more effectively inhibited hydrate growth. The results suggest that the hydrate growth inhibition is attributed to both the shape complementarity and the flexibility of binding residues. The synergy between hydrophobic and hydrophilic groups provides guidance for the design of more effective hydrate inhibitors.

ALKBH5 inhibitors as a potential treatment strategy in heart failure-inferences from gene expression profiling.

Heart Failure (HF) is a complex clinical syndrome in which the heart is unable to provide enough blood flow to meet metabolic needs and lacks efficient venous return. HF is a major risk factor for morbidity and mortality with cardiovascular diseases globally. Despite enormous research, the molecular markers relevant to disease prognosis and management remain not well understood. Here, we analyzed the whole transcriptomes of 18 failing hearts and 15 non-failing hearts (predominantly of Caucasian origin), by applying the standard in silico tools. The analyses revealed novel gene-markers including ALKBH5 of mRNA demethylation and KMT2E of histone modification processes, significantly over-expressed in the HF compared with the non-failing hearts (FDR < 0.05). To validate the over-expression of ALKBH5, we determined the global m6A level in hypoxic H9c2 cells using a dot blot assay. The global m6A level was found markedly lower in the hypoxic H9c2 cells than in the control cells. Additionally, the expression of ALKBH5 in the H9c2 cells was quantified by the qPCR and found to be 1.18 times higher at 12 h (p < 0.05), and 1.67 times higher at 24 h of hypoxia (p < 0.01) compared with the control cells, indicating a likely role of ALKBH5 in the failing cardiac cells. Furthermore, we identified several compounds through the virtual screening of 11,272 drug-like molecules of the ZINC15 database to inhibit the ALKBH5 in a molecular docking process. Collectively, the study revealed novel markers potentially involved in the pathophysiology of HF and suggested plausible therapeutic molecules for the management of the disease.

Epigenetic Regulation of Macrophage Polarization in Cardiovascular Diseases.

Cardiovascular diseases (CVDs) are the leading cause of hospitalization and death worldwide, especially in developing countries. The increased prevalence rate and mortality due to CVDs, despite the development of several approaches for prevention and treatment, are alarming trends in global health. Chronic inflammation and macrophage infiltration are key regulators of the initiation and progression of CVDs. Recent data suggest that epigenetic modifications, such as DNA methylation, posttranslational histone modifications, and RNA modifications, regulate cell development, DNA damage repair, apoptosis, immunity, calcium signaling, and aging in cardiomyocytes; and are involved in macrophage polarization and contribute significantly to cardiac disease development. Cardiac macrophages not only trigger damaging inflammatory responses during atherosclerotic plaque formation, myocardial injury, and heart failure but are also involved in tissue repair, remodeling, and regeneration. In this review, we summarize the key epigenetic modifications that influence macrophage polarization and contribute to the pathophysiology of CVDs, and highlight their potential for the development of advanced epigenetic therapies.

Recent development of multi-target VEGFR-2 inhibitors for the cancer therapy.

Vascular epidermal growth factor receptor-2 (VEGFR-2), as an important tyrosine transmembrane protein, plays an important role in regulating endothelial cell proliferation and migration, regulating angiogenesis and other biological functions. VEGFR-2 is aberrantly expressed in many malignant tumors, and it is also related to the occurrence, development, and growth of tumors and drug resistance. Currently, there are nine VEGFR-2 targeted inhibitors approved by US.FDA for clinical use as anticancer drugs. Due to the limited clinical efficacy and potential toxicity of VEGFR inhibitors, it is necessary to develop new strategies to improve the clinical efficacy of VEGFR inhibitors. The development of multitarget therapy, especially dual-target therapy, has become a hot research field of cancer therapy, which may provide an effective strategy with higher therapeutic efficacy, pharmacokinetic advantages and low toxicity. Many groups have reported that the therapeutic effects could be improved by simultaneously inhibiting VEGFR-2 and other targets, such as EGFR, c-Met, BRAF, HDAC, etc. Therefore, VEGFR-2 inhibitors with multi-targeting capabilities have been considered to be promising and effective anticancer agents for cancer therapy. In this work, we reviewed the structure and biological functions of VEGFR-2, and summarized the drug discovery strategies, and inhibitory activities of VEGFR-2 inhibitors with multi-targeting capabilities reported in recent years. This work might provide the reference for the development of VEGFR-2 inhibitors with multi-targeting capabilities as novel anticancer agents.

Recognition of driver genes with potential prognostic implications in lung adenocarcinoma based on H3K79me2.

Lung adenocarcinoma is a malignancy with a low overall survival and a poor prognosis. Studies have shown that lung adenocarcinoma progression relates to locus-specific/global changes in histone modifications. To explore the relationship between histone modification and gene expression changes, we focused on 11 histone modifications and quantitatively analyzed their influences on gene expression. We found that, among the studied histone modifications, H3K79me2 displayed the greatest impact on gene expression regulation. Based on the Shannon entropy, 867 genes with differential H3K79me2 levels during tumorigenesis were identified. Enrichment analyses showed that these genes were involved in 16 common cancer pathways and 11 tumors and were target-regulated by trans-regulatory elements, such as Tp53 and WT1. Then, an open-source computational framework was presented (https://github.com/zlq-imu/Identification-of-potential-LUND-driver-genes). Twelve potential driver genes were extracted from the genes with differential H3K79me2 levels during tumorigenesis. The expression levels of these potential driver genes were significantly increased/decreased in tumor cells, as assayed by RT-qPCR. A risk score model comprising these driver genes was further constructed, and this model was strongly negatively associated with the overall survival of patients in different datasets. The proportional hazards assumption and outlier test indicated that this model could robustly distinguish patients with different survival rates. Immune analyses and responses to immunotherapeutic and chemotherapeutic agents showed that patients in the high and low-risk groups may have distinct tendencies for clinical selection. Finally, the regions with clear H3K79me2 signal changes on these driver genes were accurately identified. Our research may offer potential molecular biomarkers for lung adenocarcinoma treatment.

A comprehensive review of SHP2 and its role in cancer.

Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) is a non-receptor protein tyrosine phosphatase ubiquitously expressed mainly in the cytoplasm of several tissues. SHP2 modulates diverse cell signaling events that control metabolism, cell growth, differentiation, cell migration, transcription and oncogenic transformation. It interacts with diverse molecules in the cell, and regulates key signaling events including RAS/ERK, PI3K/AKT, JAK/STAT and PD-1 pathways downstream of several receptor tyrosine kinases (RTKs) upon stimulation by growth factors and cytokines. SHP2 acts as both a phosphatase and a scaffold, and plays prominently oncogenic functions but can be tumor suppressor in a context-dependent manner. It typically acts as a positive regulator of RTKs signaling with some inhibitory functions reported as well. SHP2 expression and activity is regulated by such factors as allosteric autoinhibition, microRNAs, ubiquitination and SUMOylation. Dysregulation of SHP2 expression or activity causes many developmental diseases, and hematological and solid tumors. Moreover, upregulated SHP2 expression or activity also decreases sensitivity of cancer cells to anticancer drugs. SHP2 is now considered as a compelling anticancer drug target and several classes of SHP2 inhibitors with different mode of action are developed with some already in clinical trial phases. Moreover, novel SHP2 substrates and functions are rapidly growing both in cell and cancer. In view of this, we comprehensively and thoroughly reviewed literatures about SHP2 regulatory mechanisms, substrates and binding partners, biological functions, roles in human cancers, and different classes of small molecule inhibitors target this oncoprotein in cancer.

Potential therapeutic strategies for myocardial infarction: the role of Toll-like receptors.

Myocardial infarction (MI) is a life-threatening condition among patients with cardiovascular diseases. MI increases the risk of stroke and heart failure and is a leading cause of morbidity and mortality worldwide. Several genetic and epigenetic factors contribute to the development of MI, suggesting that further understanding of the pathomechanism of MI might help in the early management and treatment of this disease. Toll-like receptors (TLRs) are well-known members of the pattern recognition receptor (PRR) family and contribute to both adaptive and innate immunity. Collectively, studies suggest that TLRs have a cardioprotective effect. However, prolonged TLR activation in the response to signals generated by damage-associated molecular patterns (DAMPs) results in the release of inflammatory cytokines and contributes to the development and exacerbation of myocardial inflammation, MI, ischemia-reperfusion injury, myocarditis, and heart failure. The objective of this review is to discuss and summarize the association of TLRs with MI, highlighting their therapeutic potential for the development of advanced TLR-targeted therapies for MI.

The caspase-1 inhibitor VX765 upregulates connexin 43 expression and improves cell-cell communication after myocardial infarction via suppressing the IL-1ß/p38 MAPK pathway.

Connexin 43 (Cx43) is the most important protein in the gap junction channel between cardiomyocytes. Abnormalities of Cx43 change the conduction velocity and direction of cardiomyocytes, leading to reentry and conduction block of the myocardium, thereby causing arrhythmia. It has been shown that IL-1ß reduces the expression of Cx43 in astrocytes and cardiomyocytes in vitro. However, whether caspase-1 and IL-1ß affect connexin 43 after myocardial infarction (MI) is uncertain. In this study we investigated the effects of VX765, a caspase-1 inhibitor, on the expression of Cx43 and cell-to-cell communication after MI. Rats were treated with VX765 (16 mg/kg, i.v.) 1 h before the left anterior descending artery (LAD) ligation, and then once daily for 7 days. The ischemic heart was collected for histochemical analysis and Western blot analysis. We showed that VX765 treatment significantly decreased the infarct area, and alleviated cardiac dysfunction and remodeling by suppressing the NLRP3 inflammasome/caspase-1/IL-1ß expression in the heart after MI. In addition, VX765 treatment markedly raised Cx43 levels in the heart after MI. In vitro experiments were conducted in rat cardiac myocytes (RCMs) stimulated with the supernatant from LPS/ATP-treated rat cardiac fibroblasts (RCFs). Pretreatment of the RCFs with VX765 (25 µM) reversed the downregulation of Cx43 expression in RCMs and significantly improved intercellular communication detected using a scrape-loading/dye transfer assay. We revealed that VX765 suppressed the activation of p38 MAPK signaling in the heart tissue after MI as well as in RCMs stimulated with the supernatant from LPS/ATP-treated RCFs. Taken together, these data show that the caspase-1 inhibitor VX765 upregulates Cx43 expression and improves cell-to-cell communication in rat heart after MI via suppressing the IL-1ß/p38 MAPK pathway.

GSK-3ß-mediated activation of NLRP3 inflammasome leads to pyroptosis and apoptosis of rat cardiomyocytes and fibroblasts.

We previously demonstrated that GSK-3ß mediates NLRP3 inflammasome activation and IL-1ß production in cardiac fibroblasts (CFs) after myocardial infarction (MI). In this study, we show how GSK-3ß-mediated activation of the NLRP3 inflammasome/caspase-1/IL-1ß pathway leads to apoptosis and pyroptosis of cardiomyocytes (CMs) and CFs. Administration of lipopolysaccharide (LPS)/ATP to primary newborn rat cardiac fibroblasts (RCFs) led to increase in proteins of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, IL-1ß, and IL-18. Additionally, the expression of caspase-3 and N-terminal fragments of gasdermin D (N-GSDMD) and the Bax/Bcl-2 ratio increased. Administration of the GSK-3ß inhibitor SB216763 reduced the levels of apoptosis- and pyroptosis-related proteins regulated by NLRP3 inflammasome activation in RCFs. Next, we transferred the culture supernatant of LPS/ATP-treated RCFs to in vitro primary newborn rat cardiomyocytes (RCMs). The results showed that SB216763 attenuate the upregulation of the ratios of Bax/Bcl-2 and the expression of caspase-3 and N-GSDMD in RCMs. Direct stimulation of RCMs and H9c2 cells with recombinant rat IL-1ß increased the p-GSK-3ß/GSK-3ß and Bax/Bcl-2 ratios and the expression of caspase-3 and N-GSDMD, while both SB216763 and TLR1 (an IL-1ß receptor inhibitor) markedly reduced these effects, as assessed using propidium iodide positive staining and the lactate dehydrogenase release assay. The caspase-11 inhibitor wedelolactone decreased the expression level of N-GSDMD but did not alter the p-GSK-3ß/GSK-3ß ratio. Lastly, we established a Sprague-Dawley rat MI model to confirm that SB216763 diminished the increase in caspase-3 and N-GSDMD expression and the Bax/Bcl-2 ratio in the ischemic area. These data demonstrate that GSK-3ß regulates apoptosis and pyroptosis of RCMs and RCFs due to NLRP3 inflammasome activation in RCFs.

The long noncoding RNA glycoLINC assembles a lower glycolytic metabolon to promote glycolysis.

Non-covalent complexes of glycolytic enzymes, called metabolons, were postulated in the 1970s, but the concept has been controversial. Here we show that a c-Myc-responsive long noncoding RNA (lncRNA) that we call glycoLINC (gLINC) acts as a backbone for metabolon formation between all four glycolytic payoff phase enzymes (PGK1, PGAM1, ENO1, and PKM2) along with lactate dehydrogenase A (LDHA). The gLINC metabolon enhances glycolytic flux, increases ATP production, and enables cell survival under serine deprivation. Furthermore, gLINC overexpression in cancer cells promotes xenograft growth in mice fed a diet deprived of serine, suggesting that cancer cells employ gLINC during metabolic reprogramming. We propose that gLINC makes a functional contribution to cancer cell adaptation and provide the first example of a lncRNA-facilitated metabolon.

Glycogen synthase kinase 3 beta inhibitor SB216763 improves Kir2.1 expression after myocardia infraction in rats.

BACKGROUND: Abnormal ion channel currents caused by myocardial electrical remodeling is one of the main causes of malignant arrhythmias. Glycogen synthase kinase 3ß (GSK-3ß) is the main therapeutic target following ischemia as it regulates nerve cell channels. However, few studies have investigated its role in myocardial electrical remodeling. The present study aimed to investigate the role of GSK-3ß in a rat myocardial infarction (MI)-induced electrical remodeling and potential effects on cardiac ionic channels including KCNJ2/Kir2.1/IK1. METHODS: Ligation of the left anterior descending artery in rats was performed to establish a MI model. The rats were randomly divided into three groups, the sham, MI, and MI + SB group. The animals in the latter group were administered SB216763 (GSK-3ß inhibitor) at a dose of 0.6 mg·kg-1·day-1. The ventricular function was assessed by echocardiography, electrocardiography, and histological analysis 7 days post-surgery. Serum was collected to measure lactate dehydrogenase and cardiac troponin I levels, and the mRNA and protein levels of the KCNJ2/Kir2.1/IK1 channel in the heart tissues were assessed. H9c2 cells were cultured to examine the effects of SB216763 on the protein expression of Kir2.1 channel under hypoxic conditions. RESULTS: The results revealed that SB216763 ameliorated acute cardiac injury and improved myocardial dysfunction. Moreover, SB216763 increased the mRNA and protein expression of Kir2.1 during MI. Furthermore, SB216763 treatment abrogated the decreased expression of Kir2.1 in H9c2 cells under hypoxic conditions. CONCLUSIONS: GSK-3ß inhibition upregulates Kir2.1 expression in a rat model of MI.