Sialyltransferase7A, a Klf4-responsive gene, promotes cardiomyocyte apoptosis during myocardial infarction

Research and application of hydrogel-encapsulated mesenchymal stem cells in the treatment of myocardial infarction

Myocardial infarction (MI) stands out as a highly lethal disease that poses a significant threat to global health. Worldwide, heart failure resulting from MI remains a leading cause of human mortality. Mesenchymal stem cell (MSC) therapy has emerged as a promising therapeutic approach, leveraging its intrinsic healing properties. Nevertheless, pervasive issues, including a low cell retention rate, suboptimal survival rate, and incomplete differentiation of MSCs, present formidable challenges for further research. The introduction and advancement of biomaterials have offered a novel avenue for the exploration of MSC therapy in MI, marking considerable progress thus far. Notably, hydrogels, among the representative biomaterials, have garnered extensive attention within the biomedical field. This review delves into recent advancements, specifically focusing on the application of hydrogels to augment MSC therapy for cardiac tissue regeneration in MI.

Mechanism of Danggui Buxue decoction in the treatment of myocardial infarction based on network pharmacology and experimental identification

Background

Myocardial infarction (MI) remains one of the major causes of high morbidity and mortality worldwide. Danggui Buxue Decoction (DBD)-an ancient Chinese herbal decoction-has been used to prevent coronary heart disease, which was called "chest palsy" in ancient clinics. However, the mechanism of DBD in the treatment of MI remains unclear. The aim of this study was to explore the effect and mechanism of DBD on MI by combining network pharmacology with in vivo experiments.

Materials and methods

First, public databases were used to identify the key active chemicals and possible targets of DBD. The MI targets were obtained from the Therapeutic Target Database, and the function of the target genes in relation to linked pathways was investigated. Subsequently, Cytoscape software was used to build a target-signaling pathway network. Finally, the efficacy of DBD therapy on MI was validated using in vivo investigations combined with molecular docking.

Results

In traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP), 27 bioactive compounds were screened from DBD. A total of 213 common targets were obtained, including 507 DBD targets and 2566 MI targets. Enrichment analysis suggests that PI3K/AKT is a potential signaling pathway for DBD-based protection. Immunofluorescence and protein blotting confirmed PI3K/AKT1, ERK2, and CASPASE-9 as the target proteins. Molecular docking analysis showed that quercetin, kaempferol, isoflavanones, isorhamnetin, hederagenin, and formononetin had high binding affinity to AKT1, ERK2, and CASPASE-9.

Conclusions

This study demonstrated that the therapeutic benefit of DBD on MI may be mediated via target proteins in the PI3K/AKT pathway, such as AKT1, ERK2, and CASPASE-9. Our study data can help to provide ideas and identify new treatment targets for MI.

miR-135a Reduces Osteosarcoma Pulmonary Metastasis by Targeting Both BMI1 and KLF4

Because of the modest response rate after surgery and chemotherapy, treatment of osteosarcoma (OS) remains challenging due to tumor recurrence and metastasis. miR-135a has been reported to act as an anticarcinogenic regulator of several cancers. However, its expression and function in osteosarcoma remain largely unknown. Here, we reported that abridged miR-135a expression in OS cells and tissues, and its expression is inversely correlated with the expression of BMI1 and KLF4, which are described as oncogenes in several cancers. Ectopic expression of miR-135a inhibited cell invasion and expression of BMI1 and KLF4 in OS cells. In vivo investigation confirmed that miR-135a acts as a tumor suppressor in OS to inhibit tumor growth and lung metastasis in xenograft nude mice. BMI1 and KLF4 were revealed to be direct targets of miR-135a, and miR-135a had a similar effect as the combination of si-BMI1 and si-KLF4 on inhibiting tumor progression and the expression of BMI1 and KLF4 in vivo. Altogether, our results demonstrate that the targeting of BMI1/KLF4 with miR-135a may provide an applicable strategy for exploring novel therapeutic approaches for OS.

Sialyltransferase7A promotes angiotensin II-induced cardiomyocyte hypertrophy via HIF-1α-TAK1 signalling pathway

AIMS

Sialylation is up-regulated during the development of cardiac hypertrophy. Sialyltransferase7A (Siat7A) mRNA is consistently over-expressed in the hypertrophic left ventricle of hypertensive rats independently of genetic background. The aims of this study were: (i) to detect the Siat7A protein levels and its roles in the pathological cardiomyocyte hypertrophy; (ii) to elucidate the effect of sialylation mediated by Siat7A on the transforming-growth-factor-β-activated kinase (TAK1) expression and activity in cardiomyocyte hypertrophy; and (iii) to clarify hypoxia-inducible factor 1 (HIF-1) expression was regulated by Siat7A and transactivated TAK1 expression in cardiomyocyte hypertrophy.

METHODS AND RESULTS

Siat7A protein level was increased in hypertrophic cardiomyocytes of human and rats subjected to chronic infusion of angiotensin II (ANG II). Delivery of adeno-associated viral (AAV9) bearing shRNA against rat Siat7A into the left ventricular wall inhibited ventricular hypertrophy. Cardiac-specific Siat7A overexpression via intravenous injection of an AAV9 vector encoding Siat7A under the cardiac troponin T (cTNT) promoter aggravated cardiac hypertrophy in ANG II-treated rats. In vitro, Siat7A knockdown inhibited the induction of Sialyl-Tn (sTn) antigen and cardiomyocyte hypertrophy stimulated by ANG II. Mechanistically, ANG II induced the activation of TAK1-nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signalling in parallel to up-regulation of Siat7A in hypertrophic cardiomyocytes. Siat7A knockdown inhibited activation of TAK1-NF-κB pathway. Interestingly, HIF-1α expression was increased in cardiomyocytes stimulated by ANG II but decreased after Siat7A knockdown. HIF-1α knockdown efficiently decreased TAK1 expression. ChIP and luciferase assays showed that HIF-1α transactivated the TAK1 promoter region (nt -1285 to -1274 bp) in the cardiomyocytes following ANG II stimulus.

CONCLUSION

Siat7A was up-regulated in hypertrophic myocardium and promoted cardiomyocyte hypertrophy via activation of the HIF-1α-TAK1-NF-κB pathway.

Epigenetic Control of circHNRNPH1 in Postischemic Myocardial Fibrosis through Targeting of TGF-β Receptor Type I

Postischemic myocardial fibrosis is a factor for the development of cardiac dysfunction and malignant cardiac arrhythmias, and no effective therapy is currently available. Circular RNAs are emerging as important epigenetic players in various biological functions; however, their roles in cardiac fibrosis are unknown. With the use of a rat model of postischemic myocardial fibrosis, we identified an increase in circHNRNPH1 in the ischemic myocardium after myocardial infarction, particularly in cardiac fibroblasts. In cardiac fibroblasts, circHNRNPH1 was responsive to transforming growth factor β1 (TGF-β1), the principal profibrotic factor. The downregulation of circHNRNPH1, in contrast to its overexpression, promoted myofibroblast migration and α-smooth muscle actin and collagen I expression and inhibited myofibroblast apoptosis. The recombinant adeno-associated virus 9 (rAAV9)-mediated, cardiac-specific knockdown of circHNNRPH1 accordingly facilitated cardiac fibrosis and aggravated cardiac dysfunction. Mechanistically, circHNRNPH1 colocalized with and sponged microRNA (miR)-216-5p in the cytoplasm of cardiac fibroblasts to induce SMAD7 (protein family of signal transduction component of the canonical transforming growth factor-β signaling pathway) expression, accelerating the degradation of TGF-β receptor I. Thus, our results indicated that circHNRNPH1 negatively regulates the fibrogenesis of cardiac fibroblasts and may provide a new therapeutic strategy for postischemic myocardial fibrosis.

Perindopril Improves Cardiac Function by Enhancing the Expression of SIRT3 and PGC-1α in a Rat Model of Isoproterenol-Induced Cardiomyopathy

Mitochondrial biosynthesis regulated by the PGC-1α-NRF1-TFAM pathway is considered a novel potential therapeutic target to treat heart failure (HF). Perindopril (PER) is an angiotensin-converting enzyme inhibitor that has proven efficacy in the prevention of HF; however, its mechanism is not well established. In this study, to investigate the mechanisms of PER in cardiac protection, a rat model of cardiomyopathy was established by continuous isoproterenol (ISO) stimulation. Changes in the body weight, heart weight index, echocardiography, histological staining, mitochondrial microstructure, and biochemical indicators were examined. Our results demonstrate that PER reduced myocardial remodeling, inhibited deterioration of cardiac function, and delayed HF onset in rats with ISO-induced cardiomyopathy. PER markedly reduced reactive oxygen species (ROS) production, increased the levels of antioxidant enzymes, inhibited mitochondrial structural destruction and increases the number of mitochondria, improved the function of the mitochondrial respiratory chain, and promoted ATP production in myocardial tissues. In addition, PER inhibited cytochrome C release in mitochondria and caspase-3 activation in the cytosol, thereby reducing the apoptosis of myocardial cells. Notably, PER remarkably up-regulated the mRNA and protein expression levels of Sirtuin 3 (SIRT3), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), nuclear respiratory factor 1 (NRF1), and mitochondrial transcription factor A (TFAM) in myocardial cells. Collectively, our results suggest that PER induces mitochondrial biosynthesis-mediated enhancement of SIRT3 and PGC-1α expression, thereby improving the cardiac function in rats with ISO-induced cardiomyopathy.

LncRNA ACART protects cardiomyocytes from apoptosis by activating PPAR-γ/Bcl-2 pathway

Cardiomyocyte apoptosis is an important process occurred during cardiac ischaemia‐reperfusion injury. Long non‐coding RNAs (lncRNA) participate in the regulation of various cardiac diseases including ischaemic reperfusion (I/R) injury. In this study, we explored the potential role of lncRNA ACART (anti‐cardiomyocyte apoptosis‐related transcript) in cardiomyocyte injury and the underlying mechanism for the first time. We found that ACART was significantly down‐regulated in cardiac tissue of mice subjected to I/R injury or cultured cardiomyocytes treated with hydrogen peroxide (H₂O₂). Knockdown of ACART led to significant cardiomyocyte injury as indicated by reduced cell viability and increased apoptosis. In contrast, overexpression of ACART enhanced cell viability and reduced apoptosis of cardiomyocytes treated with H₂O₂. Meanwhile, ACART increased the expression of the B cell lymphoma 2 (Bcl‐2) and suppressed the expression of Bcl‐2‐associated X (Bax) and cytochrome‐C (Cyt‐C). In addition, PPAR‐γ was up‐regulated by ACART and inhibition of PPAR‐γ abolished the regulatory effects of ACART on cell apoptosis and the expression of Bcl‐2, Bax and Cyt‐C under H₂O₂ treatment. However, the activation of PPAR‐γ reversed the effects of ACART inhibition. The results demonstrate that ACART protects cardiomyocyte injury through modulating the expression of Bcl‐2, Bax and Cyt‐C, which is mediated by PPAR‐γ activation. These findings provide a new understanding of the role of lncRNA ACART in regulation of cardiac I/R injury.

Exosomes derived from adipose tissue, bone marrow, and umbilical cord blood for cardioprotection after myocardial infarction

Human mesenchymal stem cells (MSCs) have the potential for improving cardiac function following myocardial infarction (MI). This study was performed to explore the cardioprotection of bone marrow mesenchymal stem cells (BMMSCs), adipose tissue-derived mesenchymal stem cells (ADMSCs), and umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) for myocardium in rats after MI. MI models were established in rats, which were injected with PBS, BMMSCs, ADMSCs, and UCMSCs. Cardiac function was detected by ultrasonic cardiogram. TTC staining, TUNEL staining, and immunohistochemistry were adopted to determine infarction area, cardiomyocyte apoptosis, and microvascular density (MVD), respectively. Exosomes were derived from BMMSCs, ADMSCs, and UCBMSCs, and identified by morphological observation and CD63 expression detection. Neonatal rat cardiomyocytes (NRCMs) were isolated and cultured with hypoxia, subjected to PBS and exosomes derived from BMMSCs, ADMSCs, and UCMSCs. Flow cytometry and enzyme-linked immunosorbent assay were used to determine NRCM apoptosis and the levels of angiogenesis-related markers (VEGF, bFGF, and HGF). According to ultrasonic cardiogram, BMMSCs, ADMSCs, and UCMSCs facilitated the cardiac function of MI rats. Furthermore, three kinds of MSCs inhibited cardiomyocyte apoptosis, infarction area, and increased MVD. NRCMs treated with exosomes derived from BMMSCs, ADMSCs, and UCMSCs reduced the NRCM apoptosis and promoted angiogenesis by increasing levels of VEGF, bFGF, and HGF. Notably, exosomes from ADMSCs had the most significant effect. On the basis of the results obtained from this study, exosomes derived from BMMSCs, ADMSCs, and UCBMSCs inhibited the cardiomyocyte apoptosis and promoted angiogenesis, thereby improving cardiac function and protecting myocardium. Notably, exosomes from ADMSCs stimulated most of the cardioprotection factors.

Upregulation of miR-93 and inhibition of LIMK1 improve ventricular remodeling and alleviate cardiac dysfunction in rats with chronic heart failure by inhibiting RhoA/ROCK signaling pathway activation

Objective: There are some researches about the role of microRNA (miRNA) in chronic heart failure (CHF) were performed, but the study about miR-93’s function in CHF is scarcely investigated. Thus, we determined to probe into the effects of miR-93 in rats with CHF by targeting LIMK1 through regulating RhoA/ROCK pathway.

Results: We found increased LIMK1 and decreased miR-93 in CHF rats, and up-regulation of miR-93 inhibited LIMK1, RhoA and ROCK1 expression in CHF rats. Up-regulation of miR-93 or inhibition of LIMK1 decreased oxidative stress, inflammatory factors, as well as apoptosis-related indicators in CHF rats. LIMK1 was confirmed as a direct target gene of miR-93.

Conclusion: Our study provides evidence that upregulated miR-93 and downregulated LIMK1 improve ventricular remodeling and reduce cardiac dysfunction in CHF rats by inhibiting RhoA/ROCK signaling pathway activation.

Methods: First, rat models of CHF were established by aortic coarctation, and the rats were injected with miR-93 mimics, LIMK1-siRNA or overexpressed-LIMK1. Then expression of miR-93, LIMK1, RhoA, and ROCK1 expression in myocardial tissues were detected, after which indices of cardiac ultrasound, hemodynamics, and oxidative stress, inflammatory factors, apoptosis-related indicators were detected via a series of assays. Finally, the targeting relationship of miR-93 and LIMK1 was verified.

Downregulation of microRNA-218 is cardioprotective against cardiac fibrosis and cardiac function impairment in myocardial infarction by binding to MITF

OBJECTIVE

This study is intended to figure out the function of microRNA-218 (miR-218) together with microphthalmia-associated transcription factor (MITF) on the cardiac fibrosis and cardiac function impairment in rat models of myocardial infarction (MI).

RESULTS

The rats with MI exhibited cardiac function impairment, cardiac fibrosis, oxidative stress, cardiomyocyte apoptosis, as well as inflammatory injury. Additionally, upregulated miR-218 and downregulated MITF were detected in cardiac tissues of MI rats. MI rats injected with miR-218 inhibitors or overexpressed MITF exhibited elevated MITF expression, improved cardiac function, and diminished pathological damages, infarct size, cardiomyocyte apoptosis, cardiac fibrosis, oxidative stress as well as inflammatory injury in cardiac tissues. Furthermore, downregulated miR-218 and MITF aggravated the conditions than downregulation of miR-218 alone in MI rats.

METHODS

MI models were performed in rats, and then the rats were injected with miR-218 inhibitors and/or MITF overexpression plasmid to elucidate the role of miR-218 and/or MITF on the cardiac function, pathological damage, cardiac fibrosis, angiogenesis, oxidative stress and inflammatory injury of cardiac tissues in MI rats by performing a series of assays.

CONCLUSION

Collectively, we found that the suppression of miR-218 alleviates cardiac fibrosis and cardiac function impairment, and stimulates angiogenesis in MI rats through inhibiting MITF.

LncRNA MALAT1 is involved in sevoflurane-induced neurotoxicity in developing rats

OBJECTIVE

The purpose of this study is to uncover the effects of long chain noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on sevoflurane-induced neurotoxicity in developing rats.

METHODS

Sevoflurane neurotoxicity model was established by sevoflurane treatment in 7-day-old Sprague-Dawley rats. The rats were treated with Sevo or MALAT1 small interfering RNA to detect the MALAT1 expression, pathological change, ultrastructure, neuronal apoptosis, expression of apoptosis-related proteins, expression of neurotrophic factors BDNF and NGF, spatial learning and memory function change, as well as neuron cell density of hippocampal tissues.

RESULTS

MALAT1 was highly expressed in hippocampus tissues of rats. Downregulation of MALAT1 alleviated the pathological change, improved the ultrastructure, inhibited apoptosis of neuronal cells, declined caspase 3 and Bax while elevated Bcl-2, BDNF and NGF, improved capability of spatial learning and memory, and increased density of hippocampal neurons in hippocampal tissues of sevoflurane-induced rats.

CONCLUSION

Suppression of MALAT1 can reduce the apoptosis of hippocampal neurons induced by sevoflurane anesthesia, improve the capability of spatial learning, and memory function and alleviate the loss of hippocampal nerve cells in developing rats. To a certain extent, it plays the role of protecting brain nerve cells.

Hypoxia-Inducible Factor 1 alpha (HIF-1α)/Vascular Endothelial Growth Factor (VEGF) Pathway Participates in Angiogenesis of Myocardial Infarction in Muscone-Treated Mice: Preliminary Study

BACKGROUND Angiogenesis plays a crucial role in myocardial infarction (MI) treatment by ameliorating myocardial remodeling, thus improving cardiac function and preventing heart failure. Muscone has been reported to have beneficial effects on cardiac remodeling in MI mice. However, the effects of muscone on angiogenesis in MI mice and its underlying mechanisms remain unknown. MATERIAL AND METHODS Mice were randomly divided into sham, MI, and MI+muscone groups. The MI mouse model was established by ligating the left anterior descending coronary artery. Mice in the sham group received the same procedure except for ligation. Mice were administered muscone or an equivalent volume of saline for 4 consecutive weeks. Cardiac function was evaluated by echocardiograph after MI for 2 and 4 weeks. Four weeks later, all mice were sacrificed and Masson's trichrome staining was used to assess myocardial fibrosis. Isolectin B4 staining was applied to evaluate the angiogenesis in mouse hearts. Immunohistochemistry, Western blot analysis, and quantitative real-time polymerase chain reaction (qPCR) were performed to analyze expression levels of HIF-1a and its downstream genes. RESULTS Compared with the MI group, muscone treatment significantly improved cardiac function and reduced myocardial fibrosis. Moreover, muscone enhanced angiogenesis in the peri-infarct region and p-VEGFR2 expression in the vascular endothelial cells. Western blot analysis and qPCR showed that muscone upregulated expression levels of HIF-1a and VEGFA. CONCLUSIONS Muscone improved cardiac function in MI mice through augmented angiogenesis. The potential mechanism of muscone treatment in regulating angiogenesis of MI mice was upregulating expression levels of HIF-1α and VEGFA.

Maduramicin induces cardiac muscle cell death by the ROS-dependent PTEN/Akt-Erk1/2 signaling pathway

Maduramicin (Mad), a polyether ionophore antibiotic, has been reported to be toxic to animals and humans because of being used at high doses or for long time, resulting in heart failure. However, the toxic mechanism of Mad in cardiac muscle cells is not well understood. Here, we show that Mad induced cell viability reduction and apoptosis in cardiac-derived H9c2, HL-1 cells, primary cardiomyocytes, and murine cardiac muscles, which was because of the inhibition of extracellular-signal-regulated kinase 1/2 (Erk1/2). Expression of constitutively active mitogen-activated protein kinase kinase 1 (MKK1) attenuated Mad-induced cell death in H9c2 cells, whereas silencing Erk1/2 or ectopic expression of dominant negative MKK1 strengthened Mad-induced cell death. Moreover, we found that both phosphatase and tensin homolog on chromosome 10 (PTEN) and protein kinase B (Akt) were implicated in the regulation of Erk1/2 inactivation and apoptosis in the cells and tissues exposed to Mad. Overexpression of dominant negative PTEN and/or constitutively active Akt, or constitutively active Akt and/or constitutively active MKK1 rescued the cells from Mad-induced dephosphorylated-Erk1/2 and cell death. Furthermore, Mad-induced reactive oxygen species (ROS) activated PTEN and inactivated Akt-Erk1/2 contributing to cell death, as N-acetyl- L-cysteine ameliorated the event. Taken together, the results disclose that Mad inhibits Erk1/2 via ROS-dependent activation of PTEN and inactivation of Akt, leading to cell death in cardiac muscle cells. Our findings suggest that manipulation of the ROS-PTEN-Akt-Erk1/2 pathway may be a potential approach to prevent Mad-induced cardiotoxicity.

Abnormal expression of miR‑133a in patients with acute myocardial infarction following radical surgery for gastric cancer and the underlying mechanism

The present study aimed to investigate the expression of microRNA (miR)‑133a in patients with or without acute myocardial infarction (AMI) following radical surgery for gastric cancer, and to explore its underlying mechanisms. Blood samples were collected from patients with or without AMI in order to detect the expression levels of miR‑133a and endothelial injury markers. In addition, an AMI rat model was established. Reverse transcription‑quantitative polymerase chain reaction was used to detect the mRNA expression levels of miR‑133a and B‑cell lymphoma 2‑like 1 (Bcl2l1). In addition, an ELISA assay was used for endothelial injury marker analysis. To investigate the effects of miR‑133a on human umbilical vein endothelial cells (HUVECs), a miR‑133a inhibitor was used. Cell proliferation and apoptosis were subsequently detected using an MTT assay and flow cytometry. Western blot analysis was also conducted to detect Bcl2l1 protein expression. The results suggested that patients with AMI exhibited significantly increased expression of endothelial injury markers (von Willebrand factor, heart‑type fatty acid‑binding protein and cardiac troponin I) and miR‑133a in blood samples compared with patients without AMI. In addition, treatment with a miR‑133a mimic was able to upregulate the expression of endothelial injury markers in an AMI rat model, whereas treatment with a miR‑133a inhibitor had the opposite effect. Furthermore, cellular experiments indicated that a miR‑133a inhibitor could promote HUVEC proliferation and reduce cell apoptosis. The present results also confirmed that miR‑133a directly targets Bcl2l1 and negatively regulates Bcl2l1 expression. In conclusion, the results of the present study suggested that miR‑133a was involved in the endothelial injury process after AMI by targeting Bcl2l1.

The Role of KLF4 in Alzheimer's Disease

Krüppel-like factor 4 (KLF₄), a member of the family of zinc-finger transcription factors, is widely expressed in range of tissues that play multiple functions. Emerging evidence suggest KLF₄’s critical regulatory effect on the neurophysiological and neuropathological processes of Alzheimer’s disease (AD), indicating that KLF₄ might be a potential therapeutic target of neurodegenerative diseases. In this review, we will summarize relevant studies and illuminate the regulatory role of KLF₄ in the neuroinflammation, neuronal apoptosis, axon regeneration and iron accumulation to clarify KLF₄’s status in the pathogenesis of AD.

The Role of MicroRNA-181a in Myocardial Fibrosis Following Myocardial Infarction in a Rat Model

Background

The role of miR-181a in the development of cardiac disease and in particular, myocardial fibrosis following myocardial infarction (MI) remains unknown. The aim of this study was to explore the role of miR-181a in myocardial fibrosis in a rat model of MI and the expression of TGF-β receptor III (TβRIII).

Material/Methods

Forty adult male Wistar rats were randomly divided into an MI model group (n=30) and a control group with (n=10). The rat MI model involved ligating the left anterior descending (LAD) coronary artery in the model group; the control group was treated with a sham operation. Cardiac function was assessed using cardiac ultrasound. Myocardial fibroblasts were extracted from the rat hearts and transfected with a miR-mimic or miR-inhibitor, and cell growth was measured using an MTT assay. The level of miR-181a expression was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blots.

Results

miR-181a expression was significantly increased during the progression of MI (P<0.05). Over-expression of miR-181a was associated with increased deposition of extracellular matrix (ECM) components, collagen I and fibronectin. This effect was reversed with the use of a miR-181a inhibitor (P<0.05). Upregulation of miR-181a suppressed the expression of TGF-β receptor III (TβRIII) by binding with 3′-UTR.

Conclusions

In this rat model of MI, the findings were that miR-181a had a role in the progression of myocardial fibrosis. The findings require further studies to determine whether miR-181a might provide a novel therapeutic target to limit myocardial fibrosis following MI.

Krüppel-like factor 4 promotes human osteosarcoma growth and metastasis via regulating CRYAB expression

Krüppel-like factor 4 (KLF4), a zinc-finger transcription factor, is an essential regulator in many cellular processes, including differentiation, proliferation, inflammation, pluripotency, and apoptosis. Along with these roles in normal cells and tissues, KLF4 has been reported as a tumor suppressor or an oncogene in many cancers. However, the role of KLF4 in osteosarcoma is largely unknown. Here we found the expression of KLF4 was significantly increased in human osteosarcoma tissues compared with the normal tissues. Elevated KLF4 promoted human osteosarcoma cell proliferation and metastasis. Subsequently, mechanistic studies revealed KLF4 specifically bound the promoter of CRYAB and upregulated CRYAB expression in human osteosarcoma cells. Moreover, we found that KLF4 enhanced osteosarcoma cell proliferation and migration via upregulating CRYAB. Therefore, our studies suggested KLF4 may be a potential target for human osteosarcoma therapy.

Pinin associates with prognosis of hepatocellular carcinoma through promoting cell proliferation and suppressing glucose deprivation-induced apoptosis

The roles of Pinin have been well studied in epithelial cell-cell adhesion and RNA alternative splicing, which suggests its involvement in cancer progression. However, little is known about the association between Pinin expression and hepatocellular carcinoma (HCC) tumorigenesis. In this study we report increased expression of Pinin in HCC tissues and cells. Elevated levels of Pinin closely associates with pathological grade and overall survival of patients with hepatocellular carcinoma. Suppression of Pinin expression via lentivirus mediated shRNA knockdown inhibits HCC cell proliferation, colony formation, cell viability, but promotes glucose deprivation (GD)-induced cell apoptosis. On the contrary, overexpression of Pinin reverses these effects observed in Pinin depleted cells. Meanwhile, overexpression of Pinin attenuates GD initiated poly ADP-ribose polymerase (PARP) cleavage and ERK1/2 dephosphorylation, which can be completely blocked with MEK1/2 inhibitor U0126. Therefore, we conclude that Pinin contributes to HCC progression and resistance to GD-induced apoptosis via maintaining ERK1/2 activation and hence may be a potential therapeutic target in hepatocellular carcinoma treatment.

Analysis of region specific gene expression patterns in the heart and systemic responses after experimental myocardial ischemia

Aims

Ischemic myocardial injury leads to the activation of inflammatory mechanisms and results in ventricular remodeling. Although great efforts have been made to unravel the molecular and cellular processes taking place in the ischemic myocardium, little is known about the effects on the surrounding tissue and other organs. The aim of this study was to determine region specific differences in the myocardium and in distant organs after experimental myocardial infarction by using a bioinformatics approach.

Methods and Results

A porcine closed chest reperfused acute myocardial infarction model and mRNA microarrays have been used to evaluate gene expression changes. Myocardial infarction changed the expression of 8903 genes in myocardial-, 856 in hepatic- and 338 in splenic tissue. Identification of myocardial region specific differences as well as expression profiling of distant organs revealed clear gene-regulation patterns within the first 24 hours after ischemia. Transcription factor binding site analysis suggested a strong role for Kruppel like factor 4 (Klf4) in the regulation of gene expression following myocardial infarction, and was therefore investigated further by immunohistochemistry. Strong nuclear Klf4 expression with clear region specific differences was detectable in porcine and human heart samples after myocardial infarction.

Conclusion

Apart from presenting a post myocardial infarction gene expression database and specific response pathways, the key message of this work is that myocardial ischemia does not end at the injured myocardium. The present results have enlarged the spectrum of organs affected, and suggest that a variety of organ systems are involved in the co-ordination of the organism´s response to myocardial infarction.

Signaling Pathways in Cardiac Myocyte Apoptosis

Cardiovascular diseases, the number 1 cause of death worldwide, are frequently associated with apoptotic death of cardiac myocytes. Since cardiomyocyte apoptosis is a highly regulated process, pharmacological intervention of apoptosis pathways may represent a promising therapeutic strategy for a number of cardiovascular diseases and disorders including myocardial infarction, ischemia/reperfusion injury, chemotherapy cardiotoxicity, and end-stage heart failure. Despite rapid growth of our knowledge in apoptosis signaling pathways, a clinically applicable treatment targeting this cellular process is currently unavailable. To help identify potential innovative directions for future research, it is necessary to have a full understanding of the apoptotic pathways currently known to be functional in cardiac myocytes. Here, we summarize recent progress in the regulation of cardiomyocyte apoptosis by multiple signaling molecules and pathways, with a focus on the involvement of these pathways in the pathogenesis of heart disease. In addition, we provide an update regarding bench to bedside translation of this knowledge and discuss unanswered questions that need further investigation.

High expression of B23 is associated with tumorigenesis and poor prognosis in bladder urothelial carcinoma

B23, a multifunctional nucleolar protein, is overexpressed in numerous cancers and is associated with tumorigenesis. However, the clinical significance and potential role of B23 in bladder urothelial carcinoma remains to be elucidated. The present study observed that the mRNA and protein expression levels of B23 were increased in bladder cancer cells and tissues. The overexpression of B23 contributed to tumorigenesis and was associated with poor prognosis in bladder cancer patients. Silencing of B23 by short hairpin RNA inhibited tumor cell growth and colony formation. In addition, knockdown of B23 suppressed the phosphorylation of extracellular signal-regulated kinase (ERK), resulting in the inactivation of the ERK signaling pathway. Therefore, the present study indicated that B23 promotes bladder cancer cell growth via activation of the ERK signaling pathway and is a novel potential biomarker for the diagnosis and prognosis of bladder cancer.

Inhibition of MiR-92a May Protect Endothelial Cells After Acute Myocardial Infarction in Rats: Role of KLF2/4

Background

This study was designed to investigate the effects of microRNA-92 (miR-92), Kruppel-like factor 2 (KLF2), and Kruppel-like factor 4 (KLF4) on endothelial injury after acute myocardial infarction (AMI).

Material/Methods

Blood samples were collected from 50 AMI patients for detection of cardiac troponin I (cTnI), heart-type fatty acid-binding protein (H-FABP), and von Willebrand factor (vWF). The Sprague-Dawley rat models of AMI (n=30) were established by ligating their left anterior descending coronary artery. The cardiac markers of AMI patients and rat models were analyzed with enzyme-linked immunosorbent assay and immunohistochemistry. Human umbilical vein endothelial cells were processed into 5 groups: control, negative control, miR-92a inhibitors, miR-92a inhibitors + KLF2 small interfering RNA (siRNA), and miR-92a inhibitors + KLF4 siRNA. Cell proliferation and apoptosis were detected using MTT assay and flow cytometry. RT-PCR and Western blot were conducted to analyze KLF2 and KLF4 expressions.

Results

AMI patients exhibited significantly higher expression of both endothelial injury markers (e.g., cTnI, H-FABP, vWF) and miR-92a in blood samples, when compared with controls (P<0.05). Model rats also had similar expressional tendencies, along with lower KLF2 and KLF4 expressions (P<0.05). Further, it could be observed in cellular experiments that treatment of miR-92a mimics can further upregulate endothelial injury markers, and miR-92a and both KLF2 and KLF4 were downregulated by miR-92a mimics (all, P<0.05). Also, the luciferase activity assay confirmed the direct binding of miR-92a to 3′ UTR of KLF2/4.

Conclusions

MiR-92a was involved in the endothelial injury process after AMI and was able to suppress KLF2 and KLF4 expression.

MiR-367 negatively regulates apoptosis induced by adriamycin in osteosarcoma cells by targeting KLF4

Diverse functions of microRNAs have been investigated in tumorigenesis in osteosarcoma (OS), involving the regulation of proliferation, invasion, migration, apoptosis and drug resistance. MiR-367 was found to be an oncogene and increased in OS. However, the function of miR-367 in drug resistance in OS cells is still unknown. In this study, we found that miR-367 was up-regulated in OS tissues and OS cell cultures. Meanwhile, treatment with adriamycin (ADR) induced apoptosis of OS cells with upregulation of miR-367. Notably, KLF4 was demonstrated to be a direct target of miR-367 by gene reporter assay, and miR-367 significantly blocked both mRNA and protein level of KLF4. In addition, overexpression of miR-367 markedly suppressed the increase of KLF4 induced by ADR in OS cells, as well as Bax and cleaved caspase-3, which were significantly reversed by anti-miR-367 transfection. Taken together, our data demonstrates that miR-367 and KLF4 play important roles in OS treatment and ADR resistance, suggesting that miR-367 is a potential biomarker of chemotherapy resistance in OS and also probably a novel therapeutic target against OS.

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miR-367 functions as an oncogene in OS targeting the tumor suppressor KLF4.

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ADR induces apoptosis in OS via miR-367/KLF4/Bax signaling pathway.

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miR-367 enhances the resistance of ADR to OS cells through suppressing KLF4.

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miR-367 could be a potential biomarker of chemotherapy resistance against OS.