Suppression of microRNA-135b-5p protects against myocardial ischemia/reperfusion injury by activating JAK2/STAT3 signaling pathway in mice during sevoflurane anesthesia

iModEst: disentangling -omic impacts on gene expression variation across genes and tissues

Many regulatory factors impact the expression of individual genes including, but not limited, to microRNA, long non-coding RNA (lncRNA), transcription factors (TFs), cis-methylation, copy number variation (CNV), and single-nucleotide polymorphisms (SNPs). While each mechanism can influence gene expression substantially, the relative importance of each mechanism at the level of individual genes and tissues is poorly understood. Here, we present the integrative Models of Estimated gene expression (iModEst), which details the relative contribution of different regulators to the gene expression of 16,000 genes and 21 tissues within The Cancer Genome Atlas (TCGA). Specifically, we derive predictive models of gene expression using tumour data and test their predictive accuracy in cancerous and tumour-adjacent tissues. Our models can explain up to 70% of the variance in gene expression across 43% of the genes within both tumour and tumour-adjacent tissues. We confirm that TF expression best predicts gene expression in both tumour and tumour-adjacent tissue whereas methylation predictive models in tumour tissues does not transfer well to tumour adjacent tissues. We find new patterns and recapitulate previously reported relationships between regulator and gene-expression, such as CNV-predicted FGFR2 expression and SNP-predicted TP63 expression. Together, iModEst offers an interactive, comprehensive atlas of individual regulator-gene-tissue expression relationships as well as relationships between regulators.

Sevoflurane Represses Proliferation and Migration of Glioma Cells by Regulating the ANRIL/let-7b-5p Axis

Background: Glioma is a malignant brain tumor with poor prognosis. Sevoflurane has been shown to have antitumor effects in various cancers. However, the underlying role and mechanism of sevoflurane in glioma is still unclear. Materials and Methods: Glioma cell lines were exposed different concentrations of sevoflurane (sev). The cell proliferation and migration were examined by Cell Counting Kit-8 (CCK-8) and Transwell assays, respectively. All protein levels were measured by Western blot. The levels of noncoding RNA in the INK4 locus (ANRIL) and let-7b-5p were detected by quantitative real-time polymerase chain reaction. The binding sites between ANRIL and let-7b-5p were predicted by StarBase v.3.0 and confirmed using dual-luciferase reporter assay. Results: Sevoflurane treatment suppressed proliferation and migration of glioma cells. The expression of ANRIL was downregulated in glioma cells after treatment with sevoflurane in a dose-dependent manner, and overexpression of ANRIL reversed sevoflurane-induced inhibition of proliferation and migration of glioma cells. Furthermore, let-7b-5p was targeted by ANRIL, and ANRIL knockdown recovered the promoting effects of silencing let-7b-5p on proliferation, migration, and JAK2/STAT3 pathway in sevoflurane-treated glioma cells. Conclusions: Sevoflurane hindered proliferation and migration through JAK2/STAT3 pathway mediated by ANRIL and let-7b-5p in glioma cells, indicating a new reference for the application of anesthetics like sevoflurane in glioma.

Depletion of microRNA-92a Enhances the Role of Sevoflurane Treatment in Reducing Myocardial Ischemia-Reperfusion Injury by Upregulating KLF4

OBJECTIVE

As some articles have highlighted the role of microRNA-92a (miR-92a) in myocardial ischemia-reperfusion injury (MI/RI), this article aimed to investigate the effect of miR-92a on Sevoflurane (Sevo)-treated MI/RI via regulation of Krüppel-like factor 4 (KLF4).

METHODS

An MI/RI rat model was established by ligating the left anterior descending coronary artery. The cardiac function, pathological changes of myocardial tissues, inflammatory response, oxidative stress and cardiomyocyte apoptosis in MI/RI rats were determined. KLF4 and miR-92a expression was detected in the myocardial tissue of rats, and the target relationship between miR-92a and KLF4 was confirmed.

RESULTS

Sevo treatment alleviated myocardial damage, inflammatory response, oxidative stress response, and cardiomyocyte apoptosis, and improved cardiac function in MI/RI rats. miR-92a increased and KLF4 decreased in the myocardial tissue of MI/RI rats. KLF4 was targeted by miR-92a. Downregulation of miR-92a or upregulation of KLF4 further enhanced the effect of Sevo treatment on MI/RI.

CONCLUSION

This study suggests that depletion of miR-92a promotes upregulation of KLF4 to improve cardiac function, reduce cardiomyocyte apoptosis and further enhance the role of Sevo treatment in alleviating MI/RI.

A review on the importance of miRNA-135 in human diseases

MicroRNA-135 (miR-135) is a microRNA which is involved in the pathoetiology of several neoplastic and non-neoplastic conditions. Both tumor suppressor and oncogenic roles have been reported for this miRNA. Studies in prostate, renal, gallbladder and nasopharyngeal cancers as well as glioma have shown down-regulation of miR-135 in cancerous tissues compared with controls. These studies have also shown the impact of miR-135 down-regulation on enhancement of cell proliferation and aggressive behavior. Meanwhile, miR-135 has been shown to be up-regulated in bladder, oral, colorectal and liver cancers. Studies in breast, gastric, lung and pancreatic cancers as well as head and neck squamous cell carcinoma have reported dual roles for miR-135. Dysregulation of miR-135 has also been noted in various non-neoplastic conditions such as Alzheimer’s disease, atherosclerosis, depression, diabetes, Parkinson, pulmonary arterial hypertension, nephrotic syndrome, endometriosis, epilepsy and allergic conditions. In the current review, we summarize the role of miR-135 in the carcinogenesis as well as development of other disorders.

Cryptotanshinone alleviates myocardial ischemia and reperfusion injury in rats to mitigate ER stress-dependent apoptosis by modulating the JAK1/STAT3 axis

OBJECTIVE

Myocardial ischemia is the stoppage or insufficiency of blood flow to the myocardium, depriving cells of oxygen supply which leads to their apoptosis or death. Currently, the management of patients has improved, making it possible to reduce myocardial infarction injury with new strategies of reperfusion and pharmacologic treatment.

METHODS

A rat model of myocardial ischemia and reperfusion injury (MIRI) was created and subjected to cryptotanshinone (CRY) with or without JAK1 inhibitor filgotinib (FILGO) treatment. H&E staining was used for histopathologic evaluation of heart injury, and TTC staining was employed for evaluation of the infarct size. Western blotting and immunofluorescence were used to measure the protein expression and qRT-PCR for determining mRNA expression.

RESULTS

CRY significantly reduced the area of the infarct, the number of apoptotic cells, and the concentrations of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) induced by ischemia/reperfusion (I/R). Subsequent analysis showed that CRY repressed the expression of caspase-12, CHOP, and GRP78, but enhanced the phosphorylation of JAK and STAT3. However, FILGO treatment markedly abolished the beneficial effect of CRY pretreatment on cardiomyocyte damage, apoptosis, cardiac function, and inhibition of endoplasmic reticulum stress (ERS)-dependent apoptosis marker proteins.

CONCLUSION

CRY may alleviate MIRI by inhibiting ERS-dependent apoptosis by activating the JAK1/STAT3 signaling pathway.

MiR-141 attenuates sepsis-induced cardiomyopathy by targeting DAPK1

OBJECTIVE

To discuss the possible effects of microRNA-141 (miR-141) in sepsis-induced cardiomyopathy (SIC) via targeting death-associated protein kinase 1 (DAPK1).

METHODS

An SIC mouse model was constructed by abdominal injection of lipopolysaccharide (LPS) and divided into control, LPS, LPS + pre-miR-141, and LPS + anti-miR-141 groups. Hemodynamic indicators and heart function indexes of mice were detected. ELISA was used to determine the serum levels of inflammatory cytokines, while TUNEL staining to observe the apoptosis of myocardial cells of mice, as well as qRT-PCR and Western blotting to clarify the expression of miR-141 and DAPK1. Lastly, in vitro experiment was also conducted on the primary neonatal rat ventricular cardiomyocytes (NRVCMs) to validate the results.

RESULTS

Mice in the LPS group, as compared to the control group, had lower left ventricular ejection fraction, left ventricular fractional shortening, left ventricular systolic pressure, and ±dp/dt, but a higher left ventricular end-diastolic pressure, while the serum expression of IL-1β, IL-6, TNF-α, and cTn-T was up-regulated evidently with the increased apoptotic index of myocardial tissues. However, miR-141 and Bcl-2/Bax were down-regulated with elevated DAPK1 and cleaved caspase-3. The above changes were ameliorated in mice from the LPS + pre-miR-141 group relative to the LPS group, while those in the LPS + anti-miR-141 group were further deteriorated. In vitro experiment showed that miR-141 overexpression could reduce the apoptosis of LPS-induced NRVCMs and the levels of inflammatory cytokines with the increased cell viability.

CONCLUSION

MiR-141 could decrease inflammatory response and reduce myocardial cell apoptosis by targeting DAPK1, thereby playing the promising protective role in SIC.

Non-energy mechanism of phosphocreatine on the protection of cell survival

If mitochondrial energy availability or oxidative metabolism is altered, patients will suffer from insufficient energy supply Phosphocreatine (PCr) not only acts as an energy carrier, but also acts as an antioxidant and defensive agent to maintain the integrity and stability of the membrane, to maintain ATP homeostasis through regulating mitochondrial respiration. Meanwhile, PCr can enhance calcium balance and reduce morphological pathological changes, ultimately, PCr helps to reduce apoptosis. On the other aspect, the activities of ATP synthase and MitCK play a crucial role in the maintenance of cellular energy metabolic function. It is interesting to note, PCr not only rises the activities of ATP synthase as well as MitCK, but also promotes these two enzymatic reactions. Additionally, PCr can also inhibit mitochondrial permeability transition in a concentration-dependent manner, prevent ROS and CytC from spilling into the cytoplasm, thereby inhibit the release of proapoptotic factors caspase-3 and caspase-9, and eventually, effectively prevent LPS-induced apoptosis of cells. Understandably, PCr prevents the apoptosis caused by abnormal mitochondrial energy metabolism and has a protective role in a non-energy manner. Moreover, recent studies have shown that PCr protects cell survival through PI3K/Akt/eNOS, MAPK pathway, and inhibition of Ang II-induced NF-κB activation. Furthermore, PCr antagonizes oxidative stress through the activation of PI3K/Akt/GSK3b intracellular pathway, PI3K/AKT-PGC1α signaling pathway, while through the promotion of SIRT3 expression to maintain normal cell metabolism. Interestingly, PCr results in delaying the time to enter pathological metabolism through the delayed activation of AMPK pathway, which is different from previous studies, now we propose the hypothesis that the "miRNA-JAK2/STAT3 -CypD pathway" may take part in protecting cells from apoptosis, PCr may be further be involved in the dynamic relationship between CypD and STAT3. Furthermore, we believe that PCr and CypD would be the central link to maintain cell survival and maintain cell stability and mitochondrial repair under the mitochondrial dysfunction caused by oxidative stress. This review provides the modern progress knowledge and views on the molecular mechanism and molecular targets of PCr in a non-energy way.

Potential role of circular RNA in cyclosporin A-induced cardiotoxicity in rats

Cyclosporin A (CsA) is a well-known and effective drug that is commonly used in autoimmune diseases and allotransplantation. However, kidney toxicity and cardiotoxicity limit its use. Circular RNAs (circRNAs) play a crucial role in disease, especially cardiovascular disease. We aimed to explore the circRNA expression profiles and potential mechanisms during CsA-induced cardiotoxicity. Sixty male adult Wistar rats were randomly divided into two groups. The CsA group was injected with CsA (15 mg/kg/day body weight) intraperitoneally (ip) for 2 weeks, whereas the control group was injected ip with the same volume of olive oil. We assessed CsA-induced cardiotoxicity by light microscopy, transferase-mediated dUTP nick-end labeling (TUNEL) staining, and electron microscopy. Microarray analysis was used to detect the expression profiles of circRNAs deregulated in the heart during CsA-induced cardiotoxicity. We confirmed the changes in circRNAs by quantitative PCR. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of the microarray data were performed. A conventional dose of CsA induced cardiotoxicity in rats. We identified 67 upregulated and 37 downregulated circRNAs compared with those in the control group. Six of 12 circRNAs were successfully verified by quantitative real-time polymerase chain reaction (qRT-PCR). GO analyses of the differentially expressed circRNAs indicated that these molecules might play important roles in CsA-induced cardiotoxicity. KEGG pathway analyses showed that the differentially expressed circRNAs in CsA-induced cardiotoxicity may be related to autophagy or the Hippo signaling pathway. We identified differential circRNA expression patterns and provided more insight into the mechanism of CsA-induced cardiotoxicity. CircRNAs may serve as potential biomarkers or therapeutic targets of CsA-mediated cardiotoxicity in the future.

Roles of noncoding RNAs in the initiation and progression of myocardial ischemia-reperfusion injury

The morbidity and mortality of myocardial ischemia-reperfusion injury (MIRI) have increased in modern society. Noncoding RNAs (ncRNAs), including lncRNAs, circRNAs, piRNAs and miRNAs, have been reported in a variety of studies to be involved in pathological initiation and developments of MIRI. Hence this review focuses on the current research regarding these ncRNAs in MIRI. We comprehensively introduce the important features of lncRNAs, circRNAs, piRNA and miRNAs and then summarize the published studies of ncRNAs in MIRI. A clarification of lncRNA-miRNA-mRNA, lncRNA-transcription factor-mRNA and circRNA-miRNA-mRNA axes in MIRI follows, to further elucidate the crucial roles of ncRNAs in MIRI. Bioinformatics analysis has revealed the biological correlation of mRNAs with MIRI. We provide a comprehensive perspective for the roles of these ncRNAs and their related networks in MIRI, providing a theoretical basis for preclinical and clinical studies on ncRNA-based gene therapy for MIRI treatment.

Sevoflurane Post-treatment Upregulated miR-203 Expression to Attenuate Cerebral Ischemia-Reperfusion-Induced Neuroinflammation by Targeting MyD88

To investigate the expression of miR-203 by sevoflurane treatment and its effect on neuroinflammation induced by cerebral ischemia-reperfusion. Rats were randomly divided into sham operation group (C), cerebral ischemia-reperfusion group (I/R), and sevoflurane treatment group (S). The neurological function score was evaluated. The area of cerebral infarction was evaluated by TTC staining. The expression of inflammatory factor in brain tissue was detected by ELISA. The apoptosis of neurons was detected by TUNEL. A miR-203 agonist and inhibitor treated the cerebral ischemia-reperfusion model. The luciferase assay verified whether miR-203 targeted MyD88. To further verify the relationship between miR-203 and MyD88, the I/R group was treated with MyD88 activator and inhibitor, and the mRNA expressions of miR-203 and MyD88 in brain tissue were detected by RT-PCR. Western blot was used to detect the expression of MyD88 protein in brain tissue, and the above experiment was repeated. Compared with the I/R group, miR-203 mRNA was significantly increased in brain tissue and the neurological function score, the area of cerebral infarction, the expression of inflammatory factor, and MyD88 mRNA were decreased in the S group (P < 0.05). After treatment of miR-203 agonist and inhibitor in the I/R group, overexpression of miR-203 could alleviate cerebral ischemia-reperfusion injury, and miR-203 inhibitor could aggravate cerebral ischemia-reperfusion injury. The miR-203 agonist could enhance the action of sevoflurane, and the miR-203 inhibitor could reverse the action of sevoflurane. miR-203 agonist treatment could inhibit the expression of MyD88 gene and protein and reduce the neuroinflammation induced by cerebral ischemia-reperfusion. The treatment of sevoflurane upregulated miR-203 expression, which targeted MyD88 and attenuate neuroinflammation induced by cerebral ischemia-reperfusion.

Desflurane protects against liver ischemia/reperfusion injury via regulating miR-135b-5p

BACKGROUND

A number of anesthetics have protective effect against ischemia-reperfusion (I/R) injury, including desflurane. But the function and molecular mechanism of desflurane in liver I/R injury have not been fully understood. The aim of this study was to investigate the effect of desflurane on liver I/R injury and further investigated the molecular mechanisms involving in miR-135b-5p.

METHODS

The models of liver I/R injury in rats were established, and received desflurane treatment throughout the injury. Serum alanine transaminase (ALT) and aspartate transaminase (AST) were measured and compared between groups. H/R-induced cell model in L02 was established, and were treated with desflurane before hypoxia. Quantitative real-time polymerase chain reaction was performed to determine the expression of miR-135b-5p in different groups. The cell apoptosis was detected using flow cytometry assay. Western blot was used for the measurement of protein levels.

RESULTS

I/R significantly increased serum levels of ALT and AST in rats, which were reversed by desflurane treatment. Desflurane also significantly attenuated the increase of cell apoptosis induced by I/R in both vivo and vitro. MiR-135b-5p significantly reversed the protective effect of desflurane against liver I/R injury. Additionally, Janus protein tyrosine kinase (JAK)2 was shown to be a target gene of miR-135b-5p, and miR-135b-5p overexpression significantly decreased the protein levels of p-JAK2, JAK2, p-STAT3.

CONCLUSION

Desflurane attenuated liver I/R injury through regulating miR-135b-5p, and JAK2 was the target gene of mIR-135b-5p. These findings provide references for further development of therapeutic strategies in liver injury.

Remifentanil protects against myocardial ischemia/reperfusion injury via miR-205-mediated regulation of PINK1

Myocardial ischemia/reperfusion (I/R) injury could lead to severe cardiovascular ischemic disease, including myocardial infarction and contractile dysfunction. Remifentanil demonstrated protective effect on myocardial I/R injury. The underlying pathophysiological mechanism was then investigated in this study. In the current study, primary cardiomyocytes were isolated from rats, and then preconditioned with remifentanil. Rats, tail vein injected with miR-205 antagomir, were subjected to infusion of remifentanil, and then subjected to regional ischemia followed by reperfusion. The results demonstrated that cell viability of hypoxia/reoxygenation-induced cardiomyocytes was increased post remifentanil, while the apoptosis was decreased accompanied with reduced cleaved caspase-3 expression. Hypoxia/reoxygenation treatment increased miR-205 and decreased PINK1 (PTEN induced putative kinase 1) expression. However, preconditioning with remifentanil reduced miR-205 and enhanced PINK1. Moreover, over-expression of miR-205 decreased PINK1 expression and counteracted the effects of remifentanil-induced increase of cell viability and decrease of cell apoptosis in hypoxia/reoxygenation-induced cardiomyocytes. Injection with miR-205 antagomir improved remifentanil-induced decrease of infarct size and LDH (lactic acid dehydrogenase) activity in rat model with I/R injury. In conclusion, miR-205 might participate in the protective effect of remifentanil in rat myocardial I/R injury via regulation of PINK1, providing a potential target for amelioration of cardiovascular ischemic disease.

Role of microRNAs in Pressure Ulcer Immune Response, Pathogenesis, and Treatment

Pressure ulcers are preventable, yet highly prevalent, chronic wounds that have significant patient morbidity and high healthcare costs. Like other chronic wounds, they are characterized by impaired wound healing due to dysregulated immune processes. This review will highlight key biochemical pathways in the pathogenesis of pressure injury and how this signaling leads to impaired wound healing. This review is the first to comprehensively describe the current literature on microRNA (miRNA, miR) regulation of pressure ulcer pathophysiology.

MicroRNA-203-mediated inhibition of doublecortin underpins cardioprotection conferred by sevoflurane in rats after myocardial ischaemia-reperfusion injury

Myocardial ischaemia‐reperfusion (I/R) injury is a serious illness with high morbidity and mortality. Mounting evidence indicates the utility of sevoflurane (SEV) in the treatment of myocardial I/R injury. This study aimed to explore the molecular mechanisms underlying the protective action of SEV against myocardial I/R injury. A rat model of myocardial I/R injury was established, and I/R rats were treated with different concentrations of SEV. MicroRNA‐203 (miR‐203) and doublecortin (DCX) expression levels were determined using reverse transcription‐quantitative polymerase chain reaction. Putative target relationship between miR‐203 and DCX was explored using dual‐luciferase reporter gene assay and RNA‐binding protein immunoprecipitation assay. Ischaemia‐reperfusion rats were treated with SEV, miR‐203 antagomir or sh‐DCX, followed by determination of oxidative stress‐ and inflammation‐related factor levels using nitrite and enzyme‐linked immunosorbent assays, and that of apoptosis‐related factors using Western blot analysis. The apoptotic rate of myocardial tissues was determined using TdT‐mediated dUTP‐biotin nick end labeling (TUNEL) staining, and the infract area was evaluated using triphenyltetrazolium chloride staining. The results showed miR‐203 was poorly expressed and DCX was highly expressed in myocardial tissues of I/R rats. Sevoflurane was found to elevate miR‐203, and miR‐203, in turn, could target and reduce DCX expression. Sevoflurane, miR‐203 overexpression or DCX silencing resulted in declined oxidative stress, inflammation, apoptosis and infarct area, ultimately alleviating myocardial I/R injury. Collectively, these findings showed that SEV‐activated miR‐203 exhibited suppressive effects on myocardial I/R injury in rats and highlighted the SEV/miR‐203/DCX axis as a promising therapeutic target for myocardial I/R injury management.

miR-135b-dependent downregulation of S100B promotes neural stem cell differentiation in a hypoxia/ischemia-induced cerebral palsy rat model

Cerebral palsy (CP) is frequently caused by brain injury during pregnancy, delivery, or the immediate postnatal period. The differentiation potential of neural stem cell (NSC) makes them effective in restoring injured tissues and organs with minimal risks of side effects. In this study, we identified a novel microRNA-135b (miR-135b) in CP and investigated its functional role in mediating NSC differentiation. CP models were established in Wistar rats and validated with the Y-maze test. Gain- and loss-of-function experimentation was performed on CP rats. Then NSCs were isolated and the expression patterns of miR-135b and S100B were altered in NSCs. S100B exhibited high expression in the hippocampus tissues of CP models, which was targeted by miR-135b. miR-135b elevation or S100B silencing resulted in promoted NSC differentiation, alleviated brain injury, and inhibited NSC apoptosis in hippocampus tissues of CP rats. S100B downregulation targeted by miR-135b overexpression contributed to the inactivation of the signal transducer and activator of transcription-3 (STAT3) pathway, which promoted NSC differentiation and proliferation but inhibited NSC apoptosis. Our results highlight the suppressor role played by miR-135b in CP by inducing NSC differentiation via inactivation of S100B-dependent STAT3 pathway.

How microRNAs affect the PD-L1 and its synthetic pathway in cancer

Programmed cell death-ligand 1 (PD-L1) is a glycoprotein that is expressed on the cell surface of both hematopoietic and nonhematopoietic cells. PD-L1 play a role in the immune tolerance and protect self-tissues from immune system attack. Dysfunction of this molecule has been highlighted in the pathogenesis of tumors, autoimmunity, and infectious disorders. MicroRNAs (miRNAs) are endogenous molecules that are classified as small non-coding RNA with approximately 20-22 nucleotides (nt) length. The function of miRNAs is based on complementary interactions with target mRNA via matching completely or incompletely. The result of this function is decay of the target mRNA or preventing mRNA translation. In the past decades, several miRNAs have been discovered which play an important role in the regulation of PD-L1 in various malignancies. In this review, we discuss the effect of miRNAs on PD-L1 expression and consider the effect of miRNAs on the synthetic pathway of PD-L1, especially during cancers.

The potential function of miR-135b-mediated JAK2/STAT3 signaling pathway during osteoblast differentiation

MC3T3-E1 cells were divided into Blank, miR-135b mimics, miR-135b inhibitors, AG490, and miR-135b inhibitors + AG490 groups. Cell viability was determined by MTT, alkaline phosphatase (ALP) activity by the corresponding kit, and mineralization by alizarin red staining. Furthermore, miR-135b, osteoblast-specific genes, and JAK2/STAT3 were detected through quantitative real-time polymerase chain reaction and Western blotting. MiR-135b downregulation was identified with increased JAK2 during osteoblast differentiation. JAK2 was confirmed as a target gene of miR-135b by dual-luciferase reporter assay. MC3T3-E1 cells in both miR-135b mimics and AG490 groups manifested decrease in cell viability, ALP activity, and mineralized nodes, as well as reductions in osteoblast-specific genes and proteins of JAK2, p-JAK2, and p-STAT3, but increase in cell apoptosis. However, opposite changes of the above factors were shown in cells from miR-135b inhibitors group. Notably, AG490 could reverse promotion effects of miR-135b inhibitors on osteoblast differentiation. Inhibiting miR-135b could activate the JAK2/STAT3 signaling pathway, thereby improving the cell viability and promoting the osteoblast differentiation.

A two-circular RNA signature of donor circFOXN2 and circNECTIN3 predicts early allograft dysfunction after liver transplantation

Background

Early allograft dysfunction (EAD) following liver transplantation is associated with poor recipient and graft survival. In recent years, circular RNAs (circRNAs) have emerged as important components of endogenous RNAs. This study aims to explore the expression profile and predictive value of graft circular RNAs for EAD after liver transplantation.

Methods

RNA sequencing was conducted to identify the circRNA profile in donor liver tissues. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) was used to identify candidate circRNAs. A novel model combining circular RNA signature was established to predict EAD based on the multivariate analysis.

Results

A total of 442 circRNAs were differentially expressed between the EAD and non-EAD groups, of which, 223 were significantly upregulated and 219 were downregulated in the EAD group (Fold change >2, P<0.05). qRT-PCR validation indicated that circFOXN2 and circNECTIN3 levels in the EAD group were significantly lower than those in the non-EAD group (P=0.038, 0.024, respectively; n=115). Among the 115 recipients, 32 recipients with high circFOXN2 expression were classified as circular RNA signature A and the rest recipients with low circFOXN2 expression were categorized into circular RNA signature B (n=33, high circNECTIN3 expression) and C (n=50, low circNECTIN3 expression). The incidence rates of EAD in signature A, B and C were significantly different (3.1%, 21.2% and 42.0%, respectively; P=0.000). According to the multivariate analysis, a novel predictive model for EAD was developed based on CIT (P=0.000) and circular RNA signature (P=0.013). The novel model displayed a high predictive value for EAD with areas under the curve (AUC) of 0.870 (95% CI: 0.797-0.942).

Conclusions

Donor circFOXN2 and circNEXTIN3 were associated with the incidence of EAD. The novel model combing the two-circular RNA signature had a high predictive value for EAD.

Matrine Protects Cardiomyocytes From Ischemia/Reperfusion Injury by Regulating HSP70 Expression Via Activation of the JAK2/STAT3 Pathway

Studies have shown that matrine showed cardiovascular protective effects; however, its role and mechanism in myocardial ischemia/reperfusion (I/R) injury remain unknown. The Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway activation and elevated heat shock protein (HSP) 70 are closely related to the prevention of myocardial I/R injury. The cardioprotective effects of matrine were determined in hypoxia/reoxygenation (H/R)-treated primary rat cardiomyocytes and left anterior descending coronary artery ligation and reperfusion animal models. The molecular mechanisms of matrine in myocardial I/R injury were focused on JAK2/STAT3 pathway activation and HSP70 expression. We found that matrine significantly increased H/R-induced the suppression of cell viability, decreased lactate dehydrogenase release, creatine kinase activity, and cardiomyocytes apoptosis in vitro. Moreover, matrine notably reduced the serum levels of creatine kinase-myocardial band (CK-MB) and cardiac troponin I, lessened the infarcted area of the heart, and decreased the apoptotic index of cardiomyocytes induced by I/R in vivo. Matrine activated the JAK2/STAT3 signaling, upregulated HSP70 expression both in vitro and in vivo. The cardioprotective effects of matrine were abrogated by AG490, a JAK2 inhibitor, and HSP70 siRNA. In addition, AG490 reduced HSP70 expression increased by matrine. In conclusion, matrine attenuates myocardial I/R injury by upregulating HSP70 expression via the activation of the JAK2/STAT3 pathway.

Dexmedetomidine protects H9c2 cardiomyocytes against oxygen-glucose deprivation/reoxygenation-induced intracellular calcium overload and apoptosis through regulating FKBP12.6/RyR2 signaling

Purpose

Intracellular calcium ([Ca²⁺]i) overload is a major cause of cell injury during myocardial ischemia/reperfusion (I/R). Dexmedetomidine (DEX) has been shown to exert anti-inflammatory and organ protective effects. This study aimed to investigate whether pretreatment with DEX could protect H9c2 cardiomyocytes against oxygen-glucose deprivation/reoxygenation (OGD/R) injury through regulating the Ca²⁺ signaling.

Methods

H9c2 cardiomyocytes were subjected to OGD for 12 h, followed by 3 h of reoxygenation. DEX was administered 1 h prior to OGD/R. Cell viability, lactate dehydrogenase (LDH) release, level of [Ca²⁺]i, cell apoptosis, and the expression of 12.6-kd FK506-binding protein/ryanodine receptor 2 (FKBP12.6/RyR2) and caspase-3 were assessed.

Results

Cells exposed to OGD/R had decreased cell viability, increased LDH release, elevated [Ca²⁺]i level and apoptosis rate, down-regulated expression of FKBP12.6, and up-regulated expression of phosphorylated-Ser2814-RyR2 and cleaved caspase-3. Pretreatment with DEX significantly blocked the above-mentioned changes, alleviating the OGD/R-induced injury in H9c2 cells. Moreover, knockdown of FKBP12.6 by small interfering RNA abolished the protective effects of DEX.

Conclusion

This study indicates that DEX pretreatment protects the cardiomyocytes against OGD/R-induced injury by inhibiting [Ca²⁺]i overload and cell apoptosis via regulating the FKBP12.6/RyR2 signaling. DEX may be used for preventing cardiac I/R injury in the clinical settings.

miRNA-145-5p induces apoptosis after ischemia-reperfusion by targeting dual specificity phosphatase 6

Disorders mainly caused by ischemia-reperfusion (I/R), including stroke and myocardial infarction, is linked to debilitating health conditions and death. Recent research indicates that microRNAs (miRNAs) mediate the process of ischemic pathology. This study investigated the effects of miR-145-5p in regulating myocardial ischemic injury. The I/R models were established in rat cardiomyocytes H9C2 and rats. Western blot analysis and quantitative polymerase chain reaction was performed to analyze protein expression. Annexin V-FITC/PI staining was conducted to evaluate cell apoptosis. The application of miR-145-5p mimics and inhibitor revealed that miR-145-5p promoted apoptosis in cardiomyocytes. Furthermore, we found that miR-145-5p directly inhibited dual specificity phosphatase 6 (DUSP6) by luciferase reporter assay. The results indicated that DUSP6 was beneficial against I/R injury through inhibiting c-Jun N-terminal kinase pathways. In conclusion, the essential roles of miR-145-5p and DUSP6 in I/R provide a novel therapeutic target to develop future intervention strategies.

Apigenin Alleviates Myocardial Reperfusion Injury in Rats by Downregulating miR-15b

Background

We investigated whether apigenin could mitigate myocardial reperfusion injury in rats, and a possible mechanism was proposed.

Material/Methods

The I-R injury model was established in rats along with a sham group as control, and the expressions of microRNA-15b (miR-15b), JAK2, and p-JAK2 in the myocardia of the 2 groups were detected. Apoptosis and reactive oxygen species (ROS) were also detected. Rats in the I-R injury model were divided into 3 groups in vivo: the 1I-R group, the 2I-R+solvent group, and the 3I-R+apigenin group. Expression of miR-15b, JAK2, p-JAK2, STAT3, and p-STAT3 in the myocardia of the 3 groups were detected. ROS content, apoptosis, MDA content, SOD, and CAT activities were detected. Rat myocardial H9C2 cells were cultured in vitro and divided into 5 treatment groups in vitro; expressions of miR-15b, JAK2, p-JAK2, STAT3, and p-STAT3 in H9C2 cells were detected, and the apoptosis and ROS content were detected by flow cytometry.

Results

We found that the increased miR-15b expression during myocardial I-R injury in rats downregulated the expression of JAK2 and activity of the JAK2-STAT3 pathway, promoted myocardial apoptosis and ROS production, and aggravated myocardial I-R injury. Apigenin treatment can downregulate miR-15b expression, increase the expression of JAK2 and the activity of JAK2-STAT3 pathway, reduce myocardial apoptosis and ROS production, and alleviate myocardial I-R injury.

Conclusions

Api treatment downregulated the expression of miR-15b and upregulated the expression of JAK2 and the activity of the JAK2-STAT3 pathway, thereby alleviating myocardial I-R injury, cardiomyocyte apoptosis, and ROS production in vitro.

Inhibition of Connexin43 hemichannels with Gap19 protects cerebral ischemia/reperfusion injury via the JAK2/STAT3 pathway in mice

Functional disruption of the neurovascular unit may lead to aggravation of ischemic cerebral injury. Connexin43 (Cx43)-dependent gap junctional channels (GJCs) are critical in maintaining brain homeostasis. However, excessive opening of hemichannels (HCs) after cerebral ischemia may cause apoptosis and finally lead to amplification of ischemic injury. Previous studies indicated that Cx43 mimetic peptides Gap26 and Gap27 may protect cerebral ischemic injury, but the latest studies showed they also inhibit the opening of GJCs, which are beneficial for neuroprotection. Recent studies showed that Gap19 is a new specific inhibitor of Cx43 HCs. We investigated the role of Gap19 on cerebral ischemia/reperfusion (I/R) injury in a mouse model of middle cerebral artery occlusion (MCAO). Ventricle-injected Gap19 significantly alleviated infarct volume, neuronal cell damage and neurological deficits after ischemia, the neuroprotective effect of Gap19 was significant stronger than Gap26. Post-treatment with TAT-Gap19 still provided neuroprotection when it was administered intraperitoneally at 4 h after reperfusion. In addition, we found that Gap19 decreased the levels of cleaved caspase-3 and Bax and increased the level of Bcl-2, suggesting the anti-apoptotic activity of specifically blocking the Cx43 HCs. Furthermore, our data indicate that Gap19 treatment increased the levels of phosphorylated JAK2 and STAT3 both in vivo and in vitro. Gap19 inhibited hemichannel activity assessed by dye uptake in astrocytes. And we detected that pSTAT3 co-localized with Cx43 together in astrocytes after oxygen glucose deprivation (OGD) injury. Finally, AG490, a blocker of the JAK2/STAT3 pathway, could reverse the neuroprotective effects of Gap19 both in vivo and in vitro. Our experiment investigated the anti-apoptotic activity of Gap19, the specific inhibitor of Cx43 HCs, and the potential mechanisms. Our results demonstrated that Gap19 plays an anti-apoptotic role via activating the JAK2/STAT3 pathway after cerebral I/R injury, indicating that specific blocking of Cx43 HCs is a potential target for ischemic stroke.

Analyses of changes in myocardial long non-coding RNA and mRNA profiles after severe hemorrhagic shock and resuscitation via RNA sequencing in a rat model

Background

Ischemia–reperfusion injury has been proven to induce organ dysfunction and death, although the mechanism is not fully understood. Long non-coding RNAs (lncRNAs) have drawn wide attention with their important roles in the gene expression of some biological processes and diseases, including myocardial ischemia–reperfusion (I/R) injury. In this paper, a total of 26 Sprague–Dawley (SD) rats were randomized into two groups: sham and ischemia–reperfusion (I/R) injury. Hemorrhagic shock was induced by removing 45% of the estimated total blood volume followed by reinfusion of shed blood. High-throughput RNA sequencing was used to analyze differentially expressed (DE) lncRNAs and messenger RNAs (mRNAs) in the heart tissue 4 h after reperfusion. Myocardial function was also evaluated.

Results

After resuscitation, the decline of myocardial function of shocked animals, expressed by cardiac output, ejection fraction, and myocardial performance index (MPI), was significant (p < 0.05). DE lncRNAs and mRNAs were identified by absolute value of fold change ≥ 2 and the false discovery rate ≤ 0.001. In rats from the I/R injury group, 851 lncRNAs and 1015 mRNAs were significantly up-regulated while 1533 lncRNAs and 1702 m RNAs were significantly down-regulated when compared to the sham group. Among the DE lncRNAs, we found 12 location-associated with some known apoptosis-related protein-coding genes which were up-regulated or down-regulated accordingly, including STAT3 and Il1r1. Real time PCR assays confirmed that the expression levels of five location-associated lncRNAs (NONRATT006032.2, NONRATT006033.2, NONRATT006034.2, NONRATT006035.2 and NONRATT029969.2) and their location-associated mRNAs (STAT3 and Il1r1) in the rats from the I/R injury group were all significantly up-regulated versus the sham group.

Conclusions

The DE lncRNAs (NONRATT006032.2, NONRATT006033.2, NONRATT006034.2 and NONRATT006035.2) could be compatible with their role in myocardial protection by stimulating their co-located gene (STAT3) after hemorrhagic shock and resuscitation. The final prognosis of I/R injury might be regulated by different genes, which is regarded as a complex network.

Electronic supplementary material

The online version of this article (10.1186/s12867-018-0113-8) contains supplementary material, which is available to authorized users.

Overexpression of miR-135b attenuates pathological cardiac hypertrophy by targeting CACNA1C

BACKGROUND

Cardiac hypertrophy is a serious factor underlying heart failure. Although a large number of pathogenic genes have been identified, the underlying molecular mechanisms of cardiac hypertrophy are still poorly understood. MicroRNAs are a class of small non-coding RNAs which regulate their target genes at the post-transcriptional level. L-type calcium channels play important role in hypertrophic signaling pathways, and CACNA1C is encoded by L-type calcium channels. Here, we hypothesize that the overexpression of miR-135b can attenuate hypertrophy by targeting CACNA1C.

METHODS

We test the functional involvement of miR-135b in cardiac hypertrophy model. In order to evaluate the effect of miR-135b in cardiac hypertrophy, miR-135b mimic, miR-135b agomir and α-MHC-miR-135b transgenic mice were used for the overexpression of miR-135b. Luciferase reporter assays were used to testify the binding of miR-135b to the CACNA1C 3'UTR.

RESULTS

Our results revealed that in a pathological cardiac hypertrophy model, the expression of miR-135b was clearly downregulated. Hypertrophic marker genes were upregulated after the knockdown of miR-135b in vitro, while the overexpression of miR-135b attenuated hypertrophy. These results suggested that miR-135b may weaken hypertrophic signals. We then explored the mechanism of miR-135b in hypertrophy and identified that CACNA1C was a target gene for miR-135b. The overexpression of miR-135b attenuated cardiac hypertrophy by targeting CACNA1C.

CONCLUSIONS

Our studies revealed that miR-135b is a critical regulator of cardiomyocyte hypertrophy. Our findings may provide a novel strategy for the treatment of cardiac hypertrophy.