MicroRNA and mRNA signatures in ischemia reperfusion injury in heart transplantation

Determination of Maximum Tolerable Cold Ischemia Time in a Mouse Model of Cervical Heterotopic Uterus Transplantation

BACKGROUND

Uterus transplantation (UTx) is an emerging treatment for uterine factor infertility. Determining the maximum tolerable cold ischemia time is crucial for successful UTx. However, the limit for cold ischemia in the uterus is unclear. This study aimed to examine cold ischemia's effects on mouse uteri and identify the maximum cold ischemia duration that uteri can endure.

METHODS

We systematically assessed the tolerance of mouse uteri to extended cold ischemia, 24 h, 36 h, and 48 h, using the cervical heterotopic UTx model. Multiple indicators were used to evaluate ischemia-reperfusion injury, including reperfusion duration, macroscopic examination, oxidative stress, inflammation, and histopathology. The function of transplants was evaluated through estrous cycle monitoring and embryo transfer.

RESULTS

Mouse uteri subjected to 48 h of cold ischemia exhibited significant delays and insufficiencies in reperfusion, substantial tissue necrosis, and loss of the estrous cycle. Conversely, uteri that underwent cold ischemia within 36 h showed long survival, regular estrous cycles, and fertility.

CONCLUSIONS

Our study demonstrated that mouse uteri can endure at least 36 h of cold ischemia, extending the known limits for cold ischemia and providing a pivotal reference for research on the prevention and treatment of cold ischemic injury in UTx.

Abnormalities of glucose and lipid metabolism in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury is a common condition in cardiovascular diseases, and the mechanism of its occurrence involves multiple complex metabolic pathways and signaling pathways. Among these pathways, glucose metabolism and lipid metabolism play important roles in regulating myocardial energy metabolism. Therefore, this article focuses on the roles of glucose metabolism and lipid metabolism in myocardial ischemia-reperfusion injury, including glycolysis, glucose uptake and transport, glycogen metabolism and the pentose phosphate pathway; and triglyceride metabolism, fatty acid uptake and transport, phospholipid metabolism, lipoprotein metabolism, and cholesterol metabolism. Finally, due to the different alterations and development of glucose metabolism and lipid metabolism in myocardial ischemia-reperfusion, there are also complex interregulatory relationships between them. In the future, modulating the equilibrium between glucose metabolism and lipid metabolism in cardiomyocytes and ameliorating aberrations in myocardial energy metabolism represent highly promising novel strategies for addressing myocardial ischemia-reperfusion injury. Therefore, a comprehensive exploration of glycolipid metabolism can offer novel theoretical and clinical insights into the prevention and treatment of myocardial ischemia-reperfusion injury.

Palmitate alters miR-2137 and miR-503-5p to induce orexigenic Npy in hypothalamic neuronal cell models: Rescue by oleate and docosahexaenoic acid

MicroRNAs (miRNAs) are short noncoding RNA implicated in the pathogenesis of obesity. One cause of obesity is excess exposure to the saturated fatty acid palmitate that can alter miRNA levels in the periphery. Palmitate also promotes obesity by acting on the hypothalamus, the central coordinator of energy homeostasis, to dysregulate hypothalamic feeding neuropeptides and induce ER stress and inflammatory signaling. We hypothesized that palmitate would alter hypothalamic miRNAs that control genes involved in energy homeostasis thereby contributing to the obesity-promoting effects of palmitate. We found that palmitate upregulated 20 miRNAs and downregulated six miRNAs in the orexigenic NPY/AgRP-expressing mHypoE-46 cell line. We focused on delineating the roles of miR-2137 and miR-503-5p, as they were strongly up- and downregulated by palmitate, respectively. Overexpression of miR-2137 increased Npy mRNA levels and downregulated Esr1 levels, while increasing C/ebpβ and Atf3 mRNA. Inhibiting miR-2137 had the opposite effect, except on Npy, which was unchanged. The most downregulated miRNA by palmitate, miR-503-5p, negatively regulated Npy mRNA levels. Exposure to the unsaturated fatty acids oleate or docosahexaenoic acid completely or partially blocked the effects of palmitate on miR-2137 and miR-503-5p as well as Npy, Agrp, Esr1, C/ebpβ and Atf3. MicroRNAs may therefore contribute to palmitate actions in dysregulating NPY/AgRP neurons. Effectively combating the deleterious effects of palmitate is crucial to help prevent or reduce the impact of obesity.

Mst1 attenuates myocardial ischemia/reperfusion injury following heterotopic heart transplantation in mice through regulating Keap1/Nrf2 axis

Ischemia reperfusion (I/R) injury remains a frequent adverse event that accompanies heart transplantation. Oxidative stress and aberrant production of free radicals were regarded as the culprit of cell death and tissue damage in post-transplant IR injury. Mst1 has been identified as a mediator of oxidative stress and Nrf2 regulates anti-oxidative enzymes, however, the interaction between Mst1 and Nrf2 anti-oxidative stress pathway remains to be clarified in the event of cardiac IR injury. Herein, the model of ischemia-reperfusion injury in heterotopic heart transplantation mice was firstly established.. We observed that cardiac IR induced upregulation of Mst1 and activation of Nrf2/HO-1pathway in mice receiving heterotopic heart transplantation. Further Cobalt dichloride-induced oxidative stress model of RAW264.7 macrophage cells were then established to mimic cardiac I/R injury, results showed that exposure to CoCl₂ induced the upregulation of Mst1 and activation of Keap1/Nrf2 pathway, and genetic ablation of Mst-1 and inhibition of Keap1/Nrf2 pathway aggravated oxidative damage in those cells. Additional in vivo study showed that transfection of Mst1 shRNA spurred ROS generation and worsened cardiac damage in IR mice. Meanwhile, Mst1-KD mice receiving heart transplantation showed markedly downregulation of Nrf2, HO-1 yet upregulation of Keap1, indicating diminished protective effect against tissue damage caused by IR probably owing to the frustration of Keap1/Nrf2 pathway. Taken together, our findings demonstrated the protective effect of Mst1 from cardiac IR injury via triggering Keap1/Nrf2 axis and suppressing ROS generation, which shed light on the promising role of Mst1 in transitional management of IR injury resulted from cardiac transplantation.

Transcription Factor YY1 Ameliorates Liver Ischemia-reperfusion Injury Through Modulating the miR-181a-5p/ESR1/ERBB2 Axis

BACKGROUND

Liver ischemia/reperfusion injury (I/RI) is characterized by inflammatory actions. Understanding the mechanistic insights underpinning inflammation is critical to developing treatment strategies. In this study, we illustrated the mechanistic insights of transcription factor Yin-Yang 1 (YY1)-mediated microRNA (miR)-181a-5p/estrogen receptor alpha (ESR1)/epidermal growth factor receptor 2 (ERBB2) axis in liver I/RI.

METHODS

First, we established liver I/RI models in mice and hypoxia-reperfusion (H/R) cell models in mouse hepatocytes (AML12). Subsequently, the expression of YY1, miR-181a-5p, and ESR1 was determined in the 2 models. I/RI mouse models were further injected with lentivirus carrying oe-YY1' and H/R-exposed AML12 cells were subjected to a series of inhibitors, mimics, and shRNAs to validate the mechanisms of YY1 in controlling miR-181a-5p and ESR1 in liver I/RI.

RESULTS

Upregulated expression of miR-181a-5p and downregulated expression of YY1 were identified in the liver tissues of liver I/RI mice and H/R-exposed hepatocytes. Moreover, overexpression of YY1 inhibited the miR-181a-5p expression and thus repressed the H/R-induced hepatocyte apoptosis and inflammation. ESR1 was further validated as a target gene of miR-181a-5p and could be negatively regulated by miR-181a-5p. miR-181a-5p inhibition elevated ESR1 expression, which consequently enhanced the ERBB2 expression and reduced H/R-induced hepatocyte apoptosis and inflammation.

CONCLUSIONS

Overall, these findings highlighted that YY1 repressed the miR-181a-5p expression and stimulated ESR1-mediated activation of ERBB2, thereby ameliorating liver I/RI. This study provides insight into the development of novel targets for liver I/RI.

Protective Role of miR-34c in Hypoxia by Activating Autophagy through BCL2 Repression

Hypoxia leads to significant cellular stress that has diverse pathological consequences such as cardiovascular diseases and cancers. MicroRNAs (miRNAs) are one of regulators of the adaptive pathway in hypoxia. We identified a hypoxia-induced miRNA, miR-34c, that was significantly upregulated in hypoxic human umbilical cord vein endothelial cells (HUVECs) and in murine blood vessels on day 3 of hindlimb ischemia (HLI). miR-34c directly inhibited BCL2 expression, acting as a toggle switch between apoptosis and autophagy in vitro and in vivo. BCL2 repression by miR-34c activated autophagy, which was evaluated by the expression of LC3-II. Overexpression of miR-34c inhibited apoptosis in HUVEC as well as in a murine model of HLI, and increased cell viability in HUVEC. Importantly, the number of viable cells in the blood vessels following HLI was increased by miR-34c overexpression. Collectively, our findings show that miR-34c plays a protective role in hypoxia, suggesting a novel therapeutic target for hypoxic and ischemic diseases in the blood vessels.

MiRNA-122 Promotes Ischemia-Reperfusion Injury after Lung Transplantation via the Toll-like Receptor Signaling Pathway

OBJECTIVE

MiRNAs have been recently implicated in the pathogenesis of ischemia-reperfusion (IR) injury. This study aimed to investigate the miRNA expression profiles in the early stages after lung transplantation (LT) and to study the involvement of the Toll-like receptor (TLR) signaling pathway in lung IR injury following LT.

METHODS

We established the left LT model in mice and selected the miRNA-122 as a research target. The mice were injected with a miRNA-122-specific inhibitor, following which pathological changes in the lung tissue were studied using different lung injury indicators. In addition, we performed deep sequencing of transplanted lung tissues to identify differentially expressed (DE) miRNAs and their target genes. These target genes were used to further perform gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis.

RESULTS

A total of 12 DE miRNAs were selected, and 2476 target genes were identified. The GO enrichment analysis predicted 6063 terms, and the KEGG analysis predicted 1554 biological pathways. Compared with the control group, inhibiting the expression of miRNA-122 significantly reduced the lung injury and lung wet/dry ratio (P<0.05). In addition, the activity of myeloperoxidase and the expression levels of tumor necrosis factor-alpha and TLR2/4 were decreased (P<0.05); whereas the expression of interleukin-10 was increased (P<0.05). Furthermore, the inhibition of miRNA-122 suppressed the IR injury-induced activation of the TLR signaling pathway.

CONCLUSION

Our findings showed the differential expression of several miRNAs in the early inflammatory response following LT. Of these, miRNA-122 promoted IR injury following LT, whereas its inhibition prevented IR injury in a TLR-dependent manner.

RRM2 Improves Cardiomyocyte Proliferation after Myocardial Ischemia Reperfusion Injury through the Hippo-YAP Pathway

Objective

Ribonucleotide reductase M2 (RRM2) as an enzyme that catalyzes the deoxyreduction of nucleosides to deoxyribonucleoside triphosphate (dNTP) has been extensively studied, and it plays a crucial role in regulating cell proliferation. However, its role in ischemia-reperfusion injury (I/RI) is still unclear.

Methods

SD rats were used as the research object to detect the expression of RRM2 in the myocardium by constructing an I/RI model. At the same time, primary SD neonatal rat cardiomyocytes were extracted, and hypoxia/reoxygenation (H/R) treatment simulated the I/RI model. Using transfection technology to overexpress RRM2 in cardiomyocytes, quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) was used to detect the expression of RRM2, Cell Counting Kit-8 (CCK-8) assay was used to detect cell viability, and immunofluorescence staining was used to detect Ki67 and EdU-positive cells. Western blot (WB) technology was used to detect YAP and its phosphorylation expression.

Results

qRT-PCR results indicated that the expression of RRM2 was inhibited in the model group, and cardiomyocytes overexpressing RRM2 can obviously promote the proliferation of primary cardiomyocytes and improve the damage of cardiac structure and function caused by I/R. At the same time, RRM2 can promote the increase of YAP protein expression and the increase of Cyclin D1 mRNA expression.

Conclusion

RRM2 expression was downregulated in myocardial tissue with I/R. After overexpression of RRM2, cardiomyocyte proliferation was upregulated and the Hippo-YAP signaling pathway was activated.

Circular RNA Foxo3 in cardiac ischemia-reperfusion injury in heart transplantation: A new regulator and target

Ischemia-reperfusion (I/R) injury occurring in heart transplantation (HT) remains as a leading cause of transplant heart graft failure. Circular RNAs (circRNAs) play important roles in gene regulation and diseases. However, the impact of circRNAs on I/R injury during HT remains unknown. This study aims to investigate the role of circular RNA Foxo3 (circFoxo3) in I/R injury in HT. Using an in vivo mouse HT model and an in vitro cardiomyocyte culture model, we demonstrated that circFoxo3 is significantly upregulated in I/R-injured hearts and hypoxia/reoxygenation (H/R)-damaged cardiomyocytes. Knockdown of circFoxo3 using siRNA not only reduces cell apoptosis and death, mitochondrial damage, and expression of apoptosis/death-related genes in vitro, but also protects heart grafts from prolonged cold I/R injury in HT. We also show that circFoxo3 interacts with Foxo3 proteins and inhibits the phosphorylation of Foxo3 and that it indirectly affects the expression of miR-433 and miR-136. In conclusion, circRNA is involved in I/R injury in HT and knockdown of circFoxo3 with siRNA can reduce I/R injury and improve heart graft function through interaction with Foxo3. This study highlights that circRNA is a new type of molecular regulator and a potential target for preventing I/R injury in HT.

Preventing alloimmune rejection using circular RNA FSCN1-silenced dendritic cells in heart transplantation

BACKGROUND

While heart transplantation is used as a standard treatment for heart failure, transplant rejection continues to pose a challenge. Recent evidence has shown that circular RNA (circRNA) is a new type of gene regulator in cell development. Our aim was to demonstrate that treatment with tolerogenic dendritic cells (Tol-DCs) generated by circular RNA FSCN1 (circFSCN1) silencing could prevent alloimmune rejection and prolong heart graft survival in heart transplantation.

METHODS

Bone marrow-derived DCs were transfected with circFSCN1 siRNA in vitro. The circFSCN1 level was measured by qRT-PCR. DC maturation was determined by flow cytometry. Mixed lymphocyte reactions (MLRs) were conducted to assess the function of DCs to activate T cells and to generate regulatory T cells (Tregs). In situ RNA hybridization and fluorescent microscopy were performed to detect the distribution of circFSCN1 in DCs. A heterotopic allogeneic murine heart transplantation was conducted where recipients were pre-treated with donor derived circFSCN1-silenced Tol-DCs. Heartbeat was monitored to assess immune rejection.

RESULTS

Exonic circFSCN1 was highly expressed in the cytoplasm of mature DCs. Knockdown of circFSCN1 using siRNA arrested DCs at an immature state, impaired DC's ability to activate T cells and enhanced Treg generation. Treatment with circFSCN1-silenced Tol-DCs prevented alloimmune rejection, prolonged allograft survival, reduced fibrosis, and induced Tregs in vivo.

CONCLUSIONS

Knockdown of circFSCN1 induces Tol-DCs and treatment with these Tol-DCs prevents alloimmune rejection and prolongs allograft survival. This is a promising therapeutic target to combat transplant rejection in heart transplantation and increases our understanding of circRNA in the immune system.

Expression Profile of Circulating MicroRNAs in Dogs With Cardiac Hypertrophy: A Pilot Study

This study aimed to identify the expression profile of circulating microRNAs in dogs with eccentric or concentric cardiac hypertrophy. A total of 291 microRNAs in serum samples of five dogs with myxomatous mitral valve degeneration (MMVD) and five dogs with pulmonic stenosis (PS) were compared with those of five healthy dogs using microarray analysis. Results of microarray analysis revealed up-regulation of cfa-miR-130b [fold change (FC) = 2.13, p = 0.014), down-regulation of cfa-miR-375 (FC = 1.51, p = 0.014), cfa-miR-425 (FC = 2.56, p = 0.045), cfa-miR-30d (FC = 3.02, p = 0.047), cfa-miR-151 (FC = 1.89, p = 0.023), cfa-miR-19b (FC = 3.01, p = 0.008), and cfa-let-7g (FC = 2.53, p = 0.015) in MMVD group which showed eccentric cardiac hypertrophy, up-regulation of cfa-miR-346 (FC = 2.74, p = 0.032), down-regulation of cfa-miR-505 (FC = 1.56, p = 0.016) in PS group which showed concentric cardiac hypertrophy, and down-regulation of cfa-miR-30c (FC = 3.45, p = 0.013 in MMVD group; FC = 3.31, p = 0.014 in PS group) and cfa-let-7b (FC = 11.42, p = 0.049 in MMVD group; FC = 5.88, p = 0.01 in PS group) in both MMVD and PS groups. In addition, the unsupervised hierarchical clustering of differentially expressed microRNAs in each group resulted in complete separation of healthy dogs from dogs with heart diseases. Therefore, eleven microRNAs among 291 microRNAs were identified as differentially expressed circulating microRNAs related to MMVD or PS in dogs. This pilot study demonstrates that the microRNAs identified in this study could be possible candidates for novel biomarker or therapeutic target related to cardiac hypertrophy in dogs.

Cardiac MicroRNA Expression Profile After Experimental Brain Death Is Associated With Myocardial Dysfunction and Can Be Modulated by Hypertonic Saline

BACKGROUND

Brain death (BD) is associated with systemic inflammatory compromise, which might affect the quality of the transplanted organs. This study investigated the expression profile of cardiac microRNAs (miRNAs) after BD, and their relationship with the observed decline in myocardial function and with the changes induced by hypertonic saline solution (HSS) treatment.

METHODS

Wistar rats were assigned to sham-operation (SHAM) or submitted to BD with and without the administration of HSS. Cardiac function was assessed for 6h with left ventricular (LV) pressure-volume analysis. We screened 641 rodent miRNAs to identify differentially expressed miRNAs (DEMs) in the heart and computational and functional analysis were performed to compare the DEMs and find their putative targets and their related enriched canonical pathways.

RESULTS

An enhanced expression in canonical pathways related to inflammation and myocardial apoptosis was observed in BD induced group, with two miRNAs, miR-30a-3p and miR-467f, correlating with the level of LV dysfunction observed after BD. Conversely, HSS treated after BD and SHAM groups showed similar enriched pathways related to the maintenance of heart homeostasis regulation, in agreement with the observation that both groups did not have significant changes in LV function.

CONCLUSIONS

These findings highlight the potential of miRNAs as biomarkers for assessing damage in BD donor hearts and to monitor the changes induced by therapeutic measures like HSS, opening a perspective to improve graft quality and to better understand the pathophysiology of BD. The possible relation of BD induced miRNA's on early and late cardiac allograft function must be investigated.Supplemental Visual Abstract; http://links.lww.com/TP/C210.

MicroRNAs as theranostic markers in cardiac allograft transplantation: from murine models to clinical practice

Congestive heart failure affects about 23 million people worldwide, and cardiac allograft transplantation remains one of the last options for patients with terminal refractory heart failure. Besides the infectious or oncological complications, the prognosis of patients after heart transplantation is affected by acute cellular or antibody-mediated rejection and allograft vasculopathy development. Current monitoring of both conditions requires the performance of invasive procedures (endomyocardial biopsy sampling and coronary angiography or optical coherence tomography, respectively) that are costly, time-demanding, and non-comfortable for the patient. Within this narrative review, we focus on the potential pathophysiological and clinical roles of microRNAs (miRNAs, miRs) in the field of cardiac allograft transplantation. Firstly, we provide a general introduction about the status of cardiac allograft function monitoring and the discovery of miRNAs as post-transcriptional regulators of gene expression and clinically relevant biomarkers found in the extracellular fluid. After this general introduction, information from animal and human studies are summarized to underline the importance of miRNAs both in the pathophysiology of the rejection process, the possibility of its modulation by altering miRNAs levels, and last but not least, about the use of miRNAs in the clinical practice to diagnose or predict the rejection occurrence.

Inositol-requiring enzyme-1 regulates phosphoinositide signaling lipids and macrophage growth

The ER-bound kinase/endoribonuclease (RNase), inositol-requiring enzyme-1 (IRE1), regulates the phylogenetically most conserved arm of the unfolded protein response (UPR). However, the complex biology and pathology regulated by mammalian IRE1 cannot be fully explained by IRE1's one known, specific RNA target, X box-binding protein-1 (XBP1) or the RNA substrates of IRE1-dependent RNA degradation (RIDD) activity. Investigating other specific substrates of IRE1 kinase and RNase activities may illuminate how it performs these diverse functions in mammalian cells. We report that macrophage IRE1 plays an unprecedented role in regulating phosphatidylinositide-derived signaling lipid metabolites and has profound impact on the downstream signaling mediated by the mammalian target of rapamycin (mTOR). This cross-talk between UPR and mTOR pathways occurs through the unconventional maturation of microRNA (miR) 2137 by IRE1's RNase activity. Furthermore, phosphatidylinositol (3,4,5) phosphate (PI(3,4,5)P₃ ) 5-phosphatase-2 (INPPL1) is a direct target of miR-2137, which controls PI(3,4,5)P₃ levels in macrophages. The modulation of cellular PI(3,4,5)P₃ /PIP₂ ratio and anabolic mTOR signaling by the IRE1-induced miR-2137 demonstrates how the ER can provide a critical input into cell growth decisions.

miR-125 family regulates XIRP1 and FIH in response to myocardial infarction

MicroRNAs (miRNAs) are powerful regulators of protein expression. Many play important roles in cardiac development and disease. While several miRNAs and targets have been well characterized, the abundance of miRNAs and the numerous potential targets for each suggest that the vast majority of these interactions have yet to be described. The goal of this study was to characterize miRNA expression in the mouse heart after coronary artery ligation (LIG) and identify novel mRNA targets altered during the initial response to ischemic stress. We performed small RNA sequencing (RNA-Seq) of ischemic heart tissue 1 day and 3 days after ligation and identified 182 differentially expressed miRNAs. We then selected relevant mRNA targets from all potential targets by correlating miRNA and mRNA expression from a corresponding RNA-Seq data set. From this analysis we chose to focus, as proof of principle, on two miRNAs from the miR-125 family, miR-125a and miR-351, and two of their potential mRNA targets, Xin actin-binding repeat-containing protein 1 (XIRP1) and factor inhibiting hypoxia-inducible factor (FIH). We found miR-125a to be less abundant and XIRP1 more abundant after ligation. In contrast, the related murine miRNA miR-351 was substantially upregulated in response to ischemic injury, and FIH expression correspondingly decreased. Luciferase reporter assays confirmed direct interactions between these miRNAs and targets. In summary, we utilized a correlative analysis strategy combining miRNA and mRNA expression data to identify functional miRNA-mRNA relationships in the heart after ligation. These findings provide insight into the response to ischemic injury and suggest future therapeutic targets.

Targeting the MicroRNA-490-3p-ATG4B-Autophagy Axis Relieves Myocardial Injury in Ischemia Reperfusion

We investigated the potential role of miR-490-3p in ischemia reperfusion (IR) injury. We first determined the expression of miR-490-3p and autophagy-related 4B cysteine (ATG4B) in IR. Then, to explore whether miR-490-3p would affect autophagy, apoptosis, and IR injury, we evaluated apoptosis, autophagy, and infarct size via gain- and loss-of-function experiments. Furthermore, we used adenovirus to enhance or inhibit the expression of ATG4B, and then measured autophagy, apoptosis, and IR injury. miR-490-3p was downregulated in the hearts during the process of IR, while ATG4B was upregulated. The inhibition of miR-490-3p or overexpression of ATG4B could promote the expression of LC3II, increase the autolysosomes, inhibit the expression of p62, and reduce infarct size. On all accounts, the inhibition of miR-490-3p could promote autophagy to reduce myocardial IR injury by upregulating ATG4B, a finding that provides new insights for the protective mechanism of autophagy in IR. Graphical Abstract.

Citrate pretreatment attenuates hypoxia/reoxygenation-induced cardiomyocyte injury via regulating microRNA-142-3p/Rac1 aix

Purpose: Citrate has a positive effect on improving the pathophysiological changes of cardiomyocytes such as cardiac failure and auricular fibrillation. However, the underlying mechanism remains still unclear.Methods: Rat cardiomyocytes were used to establish hypoxia/reoxygenation (H/R) cell model. Citrate was conduct to pretreat with cardiomyocytes, and microRNA-142-3p (miR-142-3p) knockdown and overexpression were used to determine the underlying mechanism of their functions in cardiomyocytes. Cell viability and apoptosis were respectively detected by CCK-8 and flow cytometry. Protein and mRNA levels were determined by Western blot and qRT-PCR. Luciferase reporter assay and Targetscan were performed to study the regulation of miR-142-3p and Rac1.Results: The level of miR-142-3p was down-regulated in H/R model, but up-regulated in cardiomyocytes following citrate treatment. Citrates attenuated H/R injury induced miR-142-3p level and cell viability, and also inhibited H/R injury induced apoptosis, LDH, MDA and autophagy. Cell viability was improved, and autophagy was suppressed by miR-142-3p mimic, while inhibitor had opposite results. Compared with H/R + miR-142-3p inhibitor group, cell viability was higher, and apoptosis and autophagy were lower in Cit + H/R + miR-142-3p inhibitor group. Furthermore, Rac1 was target gene of miR-142-3p, and decreased by citrate, in comparison with H/R + miR-142-3p inhibitor group.Conclusion: Taken together, our findings indicated that citrate ameliorates H/R injury-induced cardiomyocytes autophagy by regulating miR-142-3p/Rac1 aix.

The role of miR-711 in cardiac cells in response to oxidative stress and its biogenesis: a study on H9C2 cells

Background

Oxidative stress results in cell apoptosis/death and plays a detrimental role in disease development and progression. Stressors alter the miRNA expression profile and miRNAs play a role in the cell response to stress. We previously showed that miR-711 is significantly over-expressed in extended cold ischemia reperfusion injured hearts in heart transplant. In this study, we aimed to investigate the role of miR-711 in cardiac cell damage in response to oxidative stress and how miR-711 is regulated.

Methods

Rat cardiac cell line H9c2 cells were cultured and exposed to oxidative conditions (Antimycin A (AA), H₂O₂, CoCl₂, or cold hypoxia/reoxygenation (H/R)) in vitro. H9c2 cells were transfected with miR-711 mimics, miR-711 inhibitors, or small interference RNA, using transfection reagents. The expression of miR-711 was measured by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Cell apoptosis/death was detected by flow cytometry and an IncuCyte system. Mitochondrial damage was detected by measuring the mitochondria membrane potential by flow cytometry. Gene expression was detected by qRT-PCR at the mRNA level and Western blotting and immunocytochemistry staining at the protein level.

Results

We found that miR-711 was significantly up-regulated in cells treated with H₂O₂, AA, CoCl₂, and cold H/R. Over-expression of miR-711 increased cell apoptosis/death induced by AA and H/R whereas cell death was reduced by miR-711 inhibitors. MiR-711 induced cell death through negative regulation of angiopoietin 1 (Ang-1), fibroblast growth factor 14 (FGF14) and calcium voltage-gated channel subunit alpha1C (Cacna1c) genes. Both knockdown of hypoxia inducible factor 1α (HIF-1α) and inactivation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NFКB) pathway inhibited over-expression of miR-711.

Conclusion

Oxidative stress increases the expression of miR-711. Over-expression of miR-711 induces cell apoptosis/death. HIF-1α and NFКB regulate miR-711 in H9c2 cells during oxidative stress. miR-711 is a new target for preventing oxidative stress.

Oxidative Stress-Responsive MicroRNAs in Heart Injury

Reactive oxygen species (ROS) are important molecules in the living organisms as a part of many signaling pathways. However, if overproduced, they also play a significant role in the development of cardiovascular diseases, such as arrhythmia, cardiomyopathy, ischemia/reperfusion injury (e.g., myocardial infarction and heart transplantation), and heart failure. As a result of oxidative stress action, apoptosis, hypertrophy, and fibrosis may occur. MicroRNAs (miRNAs) represent important endogenous nucleotides that regulate many biological processes, including those involved in heart damage caused by oxidative stress. Oxidative stress can alter the expression level of many miRNAs. These changes in miRNA expression occur mainly via modulation of nuclear factor erythroid 2-related factor 2 (Nrf2), sirtuins, calcineurin/nuclear factor of activated T cell (NFAT), or nuclear factor kappa B (NF-κB) pathways. Up until now, several circulating miRNAs have been reported to be potential biomarkers of ROS-related cardiac diseases, including myocardial infarction, hypertrophy, ischemia/reperfusion, and heart failure, such as miRNA-499, miRNA-199, miRNA-21, miRNA-144, miRNA-208a, miRNA-34a, etc. On the other hand, a lot of studies are aimed at using miRNAs for therapeutic purposes. This review points to the need for studying the role of redox-sensitive miRNAs, to identify more effective biomarkers and develop better therapeutic targets for oxidative-stress-related heart diseases.

Plk2 Regulated by miR-128 Induces Ischemia-Reperfusion Injury in Cardiac Cells

Ischemia-reperfusion (I/R) injury occurs during cardiac surgery and is the major factor leading to heart dysfunction and heart failure. Our previous study showed that gene and microRNA expression profiles are altered in heart grafts with extended I/R injury. In this study, we, for the first time, demonstrated that I/R injury upregulates the expression of Polo-like kinase 2 (Plk2) but decreases miR-128 expression in heart cells both in vitro and in vivo. Silencing Plk2 using small interfering RNA (siRNA) protects cells from Antimycin A-induced cell apoptosis/death. Silencing Plk2 also decreases phosphorylated p65 expression but increases Angiopoietin 1 expression. In addition, Plk2 is negatively regulated by miR-128. miR-128 exerts a protective effect on cell apoptosis similar to Plk2 siRNA in response to I/R stress. Methylation inhibitor 5-azacytidine (5-AZ) increases the expression of miR-128 and subsequently reduces Plk2 expression and cell apoptosis. In conclusion, this study demonstrated that Plk2 regulated by miR-128 induces cell apoptosis/death in response to I/R stress through activation of the nuclear factor κB (NF-κB) signal pathway. miR-128 and Plk2 are new targets for preventing cardiac I/R injury or oxidative stress-mediated injury.

Inhibition of microRNA-711 limits angiopoietin-1 and Akt changes, tissue damage, and motor dysfunction after contusive spinal cord injury in mice

Spinal cord injury (SCI) causes neuronal cell death and vascular damage, which contribute to neurological dysfunction. Given that many biochemical changes contribute to such secondary injury, treatment approaches have increasingly focused on combined therapies or use of multi-functional drugs. MicroRNAs (miRs) are small (20-23 nucleotide), non-protein-coding RNAs and can negatively regulate target gene expression at the post-transcriptional level. As individual miRs can potentially modulate expression of multiple relevant proteins after injury, they are attractive candidates as upstream regulators of the secondary SCI progression. In the present study we examined the role of miR-711 modulation after SCI. Levels of miR-711 were increased in injured spinal cord early after SCI, accompanied by rapid downregulation of its target angiopoietin-1 (Ang-1), an endothelial growth factor. Changes of miR-711 were also associated with downregulation of the pro-survival protein Akt (protein kinase B), another target of miR-711, with sequential activation of glycogen synthase kinase 3 and the pro-apoptotic BH3-only molecule PUMA. Central administration of a miR-711 hairpin inhibitor after SCI limited decreases of Ang-1/Akt expression and attenuated apoptotic pathways. Such treatment also reduced neuronal/axonal damage, protected microvasculature and improved motor dysfunction following SCI. In vitro, miR-711 levels were rapidly elevated by neuronal insults, but not by activated microglia and astrocytes. Together, our data suggest that post-traumatic miR-711 elevation contributes to neuronal cell death after SCI, in part by inhibiting Ang-1 and Akt pathways, and may serve as a novel therapeutic target.

LncRNA ROR is involved in cerebral hypoxia/reoxygenation-induced injury in PC12 cells via regulating miR-135a-5p/ROCK1/2

Ischemic stroke is a common cerebrovascular disease with high morbidity, disability and mortality. LncRNAs were involved in ischemia/reperfusion injury. The present study aims to investigate whether lncRNA ROR can promote the cerebral hypoxia/reoxygenation (H/R) injury in vitro, a cellular model of cerebral ischemia/reperfusion injury, through inhibiting the expression of miR-135a-5p or upregulating the expression of ROCK1 and ROCK2. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the lncRNA ROR expression in PC12 cells induced by H/R and verify the transfection effect. ROS, LDH, SOD and MDA levels were detected by respective kits. CCK-8 assay and flow cytometry analysis respectively detected the cell viability and cell apoptosis. Western blot analysis was to analyze the expression of apoptosis-related proteins (Bcl-2, Bax and cleaved caspase3). Immunofluorescent staining detected the ROCK1/2 expression. As a result, lncRNA ROR expression was increased in the PC12 cells induced by H/R. LncRNA ROR overexpression could aggravate injury of PC12 cells induced by H/R. And, lncRNA ROR overexpression could decrease viability and promote apoptosis of PC12 cells induced by H/R. In addition, miR-135a-5p was demonstrated to be a target of lncRNA ROR and lncRNA ROR improved H/R injury in PC12 cells by up-regulating the expression of miR-135a-5p via down-regulating ROCK1/2 expression. In conclusion, this study indicated that lncRNA ROR could promote the cerebral H/R injury by inhibiting the expression of miR-135a-5p or upregulating the expression of ROCK1/2. And, miR-135a-5p overexpression could improve the cerebral H/R injury by inhibiting the expression of ROCK1/2.

Mitochondrial transplantation prolongs cold ischemia time in murine heart transplantation

BACKGROUND

Cold ischemia time (CIT) causes ischemia‒reperfusion injury to the mitochondria and detrimentally effects myocardial function and tissue viability. Mitochondrial transplantation replaces damaged mitochondria and enhances myocardial function and tissue viability. Herein we investigated the efficacy of mitochondrial transplantation in enhancing graft function and viability after prolonged CIT.

METHODS

Heterotopic heart transplantation was performed in C57BL/6J mice. Upon heart harvesting from C57BL/6J donors, 0.5 ml of either mitochondria (1 × 10⁸ in respiration buffer; mitochondria group) or respiration buffer (vehicle group) was delivered antegrade to the coronary arteries via injection to the coronary ostium. The hearts were excised and preserved for 29 ± 0.3 hours in cold saline (4°C). The hearts were then heterotopically transplanted. A second injection of either mitochondria (1 × 10⁸) or respiration buffer (vehicle) was delivered antegrade to the coronary arteries 5 minutes after transplantation. Grafts were analyzed for 24 hours. Beating score, graft function, and tissue injury were measured.

RESULTS

Beating score, calculated ejection fraction, and shortening fraction were significantly enhanced (p < 0.05), whereas necrosis and neutrophil infiltration were significantly decreased (p < 0.05) in the mitochondria group as compared with the vehicle group at 24 hours of reperfusion. Transmission electron microscopy showed the presence of contraction bands in vehicle but not in mitochondria grafts.

CONCLUSIONS

Mitochondrial transplantation prolongs CIT to 29 hours in the murine heart transplantation model, significantly enhances graft function, and decreases graft tissue injury. Mitochondrial transplantation may provide a means to reduce graft failure and improve transplantation outcomes after prolonged CIT.

MicroRNA-711-Induced Downregulation of Angiopoietin-1 Mediates Neuronal Cell Death

Angiopoietin-1 (Ang-1) is a well-known endothelial growth factor, but its effects on neurons have yet to be elucidated. We show that Ang-1 is rapidly downregulated in the injured brain after controlled cortical impact (CCI), a mouse experimental traumatic brain injury (TBI) model and in etoposide-induced neuronal apoptosis in vitro. Ang-1 treatment inhibits etoposide-induced upregulation of proapoptotic B-cell lymphoma 2 (Bcl-2) family members Noxa, p53 upregulated modulator of apoptosis (Puma), Bcl-2 interacting mediator of cell death (Bim), and Bcl-2-associated X protein (Bax); reduces markers of caspase-dependent (cytochrome c release/caspase activation) and caspase-independent (apoptosis-inducing factor release) pathways; and limits neuronal cell death. Ang-1 treatment phosphorylates receptors Tunica interna endothelial cell kinase 2 (Tie2), and β1-integrin and limits the etoposide-induced decrease in protein kinase B (Akt) activity. Blocking Tie2 and β1-integrin signaling reduces Ang-1 neuroprotective effects. After both TBI and etoposide treatment microRNA (miR)-711 are upregulated, consistent with its putative role as a negative regulator of Ang-1. We show that miR-711 directly targets the Ang-1 messenger RNA (mRNA), decreasing Ang-1 expression. Increased levels of miR-711 and Ang-1 mRNA are found in the RNA-induced silencing complex complex site of miR-mediated degradation of target mRNAs after etoposide treatment and the miR-711mimic downregulates Ang-1. Administration of miR-711 inhibitor elevates Ang-1 after TBI whereas Ang-1 administration increases Akt activation; reduces Puma, Noxa, Bim, and Bax levels; and attenuates caspase-dependent and -independent neuronal apoptosis 24 h after TBI. Ang-1 also attenuates neuronal degeneration, increases gene expression of molecules that maintain blood-brain barrier integrity, and reduces post-traumatic lesion volume/edema 24 h after TBI. Although we only observed short-term neuroprotective effects after Ang-1 administration, miR-711-dependent downregulation of Ang-1, followed by Akt pathway inhibition, may play a role in neuronal cell death after neuronal injury in vitro and after experimental TBI.

Altered MicroRNA Profile in Osteoporosis Caused by Impaired WNT Signaling

CONTEXT

WNT signaling is fundamental to bone health, and its aberrant activation leads to skeletal pathologies. The heterozygous missense mutation p.C218G in WNT1, a key WNT pathway ligand, leads to severe early-onset and progressive osteoporosis with multiple peripheral and spinal fractures. Despite the severe skeletal manifestations, conventional bone turnover markers are normal in mutation-positive patients.

OBJECTIVE

This study sought to explore the circulating microRNA (miRNA) pattern in patients with impaired WNT signaling.

DESIGN AND SETTING

A cross-sectional cohort study at a university hospital.

PARTICIPANTS

Altogether, 12 mutation-positive (MP) subjects (median age, 39 years; range, 11 to 76 years) and 12 mutation-negative (MN) subjects (35 years; range, 9 to 59 years) from two Finnish families with WNT1 osteoporosis due to the heterozygous p.C218G WNT1 mutation.

METHODS AND MAIN OUTCOME MEASURE

Serum samples were screened for 192 miRNAs using quantitative polymerase chain reaction. Findings were compared between WNT1 MP and MN subjects.

RESULTS

The pattern of circulating miRNAs was significantly different in the MP subjects compared with the MN subjects, with two upregulated (miR-18a-3p and miR-223-3p) and six downregulated miRNAs (miR-22-3p, miR-31-5p, miR-34a-5p, miR-143-5p, miR-423-5p, and miR-423-3p). Three of these (miR-22-3p, miR-34a-5p, and miR-31-5p) are known inhibitors of WNT signaling: miR-22-3p and miR-34a-5p target WNT1 messenger RNA, and miR-31-5p is predicted to bind to WNT1 3'UTR.

CONCLUSIONS

The circulating miRNA pattern reflects WNT1 mutation status. The findings suggest that the WNT1 mutation disrupts feedback regulation between these miRNAs and WNT1, providing insights into the pathogenesis of WNT-related bone disorders. These miRNAs may have potential in the diagnosis and treatment of osteoporosis.

miR-190 protects cardiomyocytes from apoptosis induced by H2O2 through targeting MAPK8 and regulating MAPK8/ERK signal pathway

MicroRNAs (miRs) have been demonstrated to regulate physiological and pathological processes. Numerous miRsprotect against cardiomyocyte injury induced by oxidative stress. However, the function of miR-190 still remains unclear. Here, we determined the expression level of miR-190 in H9c2 cells under H₂O₂ treatment and found that miR-190 expression was significantly inhibited by H₂O₂. Further study indicated that miR-190 significantly reduced cell apoptosisand the LDH and MDA levels of H9c2 cells induced by H₂O₂. Luciferase activity assay, quantitative real-time-PCR, and Western blot demonstrated that miR-190 directly targets MAPK8. Rescue experiment confirmed this hypothesis. Further study has revealed that miR-190 protects H9c2 cells from oxidative stress injury through inhibiting the MAPK8/ERK signal pathway. In conclusion, these data suggest that miR-190 protects against oxidative stress injury of H9c2 cells induced by H₂O₂ through inhibiting MAPK8 expression and the MAPK8/ERK pathway. Our findings provide a potential therapeutic target to promote functional recovery after cardiac ischemia/reperfusion.

Maternal Choline Supplementation during Normal Murine Pregnancy Alters the Placental Epigenome: Results of an Exploratory Study

The placental epigenome regulates processes that affect placental and fetal development, and could be mediating some of the reported effects of maternal choline supplementation (MCS) on placental vascular development and nutrient delivery. As an extension of work previously conducted in pregnant mice, the current study sought to explore the effects of MCS on various epigenetic markers in the placenta. RNA and DNA were extracted from placentas collected on embryonic day 15.5 from pregnant mice fed a 1X or 4X choline diet, and were subjected to genome-wide sequencing procedures or mass-spectrometry-based assays to examine placental imprinted gene expression, DNA methylation patterns, and microRNA (miRNA) abundance. MCS yielded a higher (fold change = 1.63-2.25) expression of four imprinted genes (Ampd3, Tfpi2, Gatm and Aqp1) in the female placentas and a lower (fold change = 0.46-0.62) expression of three imprinted genes (Dcn, Qpct and Tnfrsf23) in the male placentas (false discovery rate (FDR) ≤ 0.05 for both sexes). Methylation in the promoter regions of these genes and global placental DNA methylation were also affected (p ≤ 0.05). Additionally, a lower (fold change = 0.3; P_unadjusted = 2.05 × 10^-4; FDR = 0.13) abundance of miR-2137 and a higher (fold change = 1.25-3.92; p < 0.05) expression of its target genes were detected in the 4X choline placentas. These data demonstrate that the placental epigenome is responsive to maternal choline intake during murine pregnancy and likely mediates some of the previously described choline-induced effects on placental and fetal outcomes.

Over-expression of growth differentiation factor 15 (GDF15) preventing cold ischemia reperfusion (I/R) injury in heart transplantation through Foxo3a signaling

Ischemia reperfusion (I/R) injury which inevitably occurs during heart transplantation is the major factor leading to organ failure and graft rejection. In order to develop new therapies to prevent I/R injury, we used both a murine heart transplantation model with 24 hour cold I/R and an in vitro cell culture system to determine whether growth differentiation factor 15 (GDF15) is a protective factor in preventing I/R injury in heart transplantation and to further investigate underlying mechanisms of I/R injury. We found that cold I/R caused severe damage to the endocardium, epicardium and myocardium of heart grafts from wild type C57BL/6 mice, whereas grafts from GDF15 transgenic (TG) mice showed less damage as demonstrated by decreased cell apoptosis/death, decreased neutrophils infiltration and the preservation of the normal structure of the heart. Over-expression of GDF15 reduced expression of phosphorylated RelA p65, pre-inflammatory and pro-apoptotic genes while it enhanced Foxo3a phosphorylation in vitro and in vivo. Over-expression of GDF15 inhibited cell apoptosis/death and reduced neutrophil infiltration. In conclusion, this study, for the first time, demonstrates that GDF15 is a promising target for preventing cold I/R injury in heart transplantation. This study also shows that the resultant protective effects are mediated by the Foxo3 and NFκB signaling pathways.

Mesenchymal stromal cell-derived extracellular vesicles attenuate lung ischemia-reperfusion injury and enhance reconditioning of donor lungs after circulatory death

Background

Lung ischemia-reperfusion (IR) injury after transplantation as well as acute shortage of suitable donor lungs are two critical issues impacting lung transplant patients. This study investigates the anti-inflammatory and immunomodulatory role of human mesenchymal stromal cells (MSCs) and MSC-derived extracellular vesicles (EVs) to attenuate lung IR injury and improve of ex-vivo lung perfusion (EVLP)-mediated rehabilitation in donation after circulatory death (DCD) lungs.

Methods

C57BL/6 wild-type (WT) mice underwent sham surgery or lung IR using an in vivo hilar-ligation model with or without MSCs or EVs. In vitro studies used primary iNKT cells and macrophages (MH-S cells) were exposed to hypoxia/reoxygenation with/without co-cultures with MSCs or EVs. Also, separate groups of WT mice underwent euthanasia and 1 h of warm ischemia and stored at 4 °C for 1 h followed by 1 h of normothermic EVLP using Steen solution or Steen solution containing MSCs or EVs.

Results

Lungs from MSCs or EV-treated mice had significant attenuation of lung dysfunction and injury (decreased edema, neutrophil infiltration and myeloperoxidase levels) compared to IR alone. A significant decrease in proinflammatory cytokines (IL-17, TNF-α, CXCL1 and HMGB1) and upregulation of keratinocyte growth factor, prostaglandin E2 and IL-10 occurred in the BAL fluid from MSC or EV-treated mice after IR compared to IR alone. Furthermore, MSCs or EVs significantly downregulated iNKT cell-produced IL-17 and macrophage-produced HMGB1 and TNF-α after hypoxia/reoxygenation. Finally, EVLP of DCD lungs with Steen solution including MSCs or EVs provided significantly enhanced protection versus Steen solution alone. Co-cultures of MSCs or EVs with lung endothelial cells prevents neutrophil transendothelial migration after exposure to hypoxia/reoxygenation and TNF-α/HMGB1 cytomix.

Conclusions

These results suggest that MSC-derived EVs can attenuate lung inflammation and injury after IR as well as enhance EVLP-mediated reconditioning of donor lungs. The therapeutic benefits of EVs are in part mediated through anti-inflammatory promoting mechanisms via attenuation of immune cell activation as well as prevention of endothelial barrier integrity to prevent lung edema. Therefore, MSC-derived EVs offer a potential therapeutic strategy to treat post-transplant IR injury as well as rehabilitation of DCD lungs.

Anti-Inflammatory Effects of Omega-3 Fatty Acids in the Brain: Physiological Mechanisms and Relevance to Pharmacology

Classically, polyunsaturated fatty acids (PUFA) were largely thought to be relatively inert structural components of brain, largely important for the formation of cellular membranes. Over the past 10 years, a host of bioactive lipid mediators that are enzymatically derived from arachidonic acid, the main n-6 PUFA, and docosahexaenoic acid, the main n-3 PUFA in the brain, known to regulate peripheral immune function, have been detected in the brain and shown to regulate microglia activation. Recent advances have focused on how PUFA regulate the molecular signaling of microglia, especially in the context of neuroinflammation and behavior. Several active drugs regulate brain lipid signaling and provide proof of concept for targeting the brain. Because brain lipid metabolism relies on a complex integration of diet, peripheral metabolism, including the liver and blood, which supply the brain with PUFAs that can be altered by genetics, sex, and aging, there are many pathways that can be disrupted, leading to altered brain lipid homeostasis. Brain lipid signaling pathways are altered in neurologic disorders and may be viable targets for the development of novel therapeutics. In this study, we discuss in particular how n-3 PUFAs and their metabolites regulate microglia phenotype and function to exert their anti-inflammatory and proresolving activities in the brain.

Attenuation of miR-34a protects cardiomyocytes against hypoxic stress through maintenance of glycolysis

MiRNAs are a class of endogenous, short, single-stranded, non-coding RNAs, which are tightly linked to cardiac disorders such as myocardial ischemia/reperfusion (I/R) injury. MiR-34a is known to be involved in the hypoxia-induced cardiomyocytes apoptosis. However, the molecular mechanisms are unclear. In the present study, we demonstrate that under low glucose supply, rat cardiomyocytes are susceptible to hypoxia. Under short-time hypoxia, cellular glucose uptake and lactate product are induced but under long-time hypoxia, the cellular glucose metabolism is suppressed. Interestingly, an adaptive up-regulation of miR-34a by long-time hypoxia was observed both in vitro and in vivo, leading to suppression of glycolysis in cardiomyocytes. We identified lactate dehydrogenase-A (LDHA) as a direct target of miR-34a, which binds to the 3′-UTR region of LDHA mRNA in cardiomyocytes. Moreover, inhibition of miR-34a attenuated hypoxia-induced cardiomyocytes dysfunction through restoration of glycolysis. The present study illustrates roles of miR-34a in the hypoxia-induced cardiomyocytes dysfunction and proposes restoration of glycolysis of dysfunctional cardiomyocytes by inhibiting miR-34a during I/R might be an effectively therapeutic approach against I/R injury.

Differential expression of microRNAs following cardiopulmonary bypass in children with congenital heart diseases

Background

Children with congenital heart defects (CHDs) are at high risk for myocardial failure after operative procedures with cardiopulmonary bypass (CPB). Recent studies suggest that microRNAs (miRNA) are involved in the development of CHDs and myocardial failure. Therefore, the aim of this study was to determine alterations in the miRNA profile in heart tissue after cardiac surgery using CPB.

Methods

In total, 14 tissue samples from right atrium were collected from patients before and after connection of the CPB. SurePrint™ 8 × 60K Human v21 miRNA array and quantitative reverse transcription-polymerase chain reaction (RT-qPCR) were employed to determine the miRNA expression profile from three patients before and after connection of the CPB. Enrichment analyses of altered miRNA expression were predicted using bioinformatic tools.

Results

According to miRNA array, a total of 90 miRNAs were significantly altered including 29 miRNAs with increased and 61 miRNAs with decreased expression after de-connection of CPB (n = 3) compared to before CPB (n = 3). Seven miRNAs had been validated using RT-qPCR in an independent cohort of 11 patients. Enrichment analyses applying the KEGG database displayed the highest correlation for signaling pathways, cellular community, cardiovascular disease and circulatory system.

Conclusion

Our result identified the overall changes of the miRNome in right atrium tissue of patients with CHDs after CPB. The differentially altered miRNAs lay a good foundation for further understanding of the molecular function of changed miRNAs in regulating CHDs and after CPB in particular.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1213-9) contains supplementary material, which is available to authorized users.

Resolvin D1 and E1 promote resolution of inflammation in microglial cells in vitro

Sustained inflammation in the brain together with microglia activation can lead to neuronal damage. Hence limiting brain inflammation and activation of microglia is a real therapeutic strategy for inflammatory disease. Resolvin D1 (RvD1) and resolvin E1 (RvE1) derived from n-3 long chain polyunsaturated fatty acids are promising therapeutic compounds since they actively turn off the systemic inflammatory response. We thus evaluated the anti-inflammatory activities of RvD1 and RvE1 in microglia cells in vitro. BV2 cells were pre-incubated with RvD1 or RvE1 before lipopolysaccharide (LPS) treatment. RvD1 and RvE1 both decreased LPS-induced proinflammatory cytokines (TNF-α, IL-6 and IL-1β) gene expression, suggesting their proresolutive activity in microglia. However, the mechanisms involved are distinct as RvE1 regulates NFκB signaling pathway and RvD1 regulates miRNAs expression. Overall, our findings support that pro-resolving lipids are involved in the resolution of brain inflammation and can be considered as promising therapeutic agents for brain inflammation.

Apoptosis-related microRNA changes in the right atrium induced by remote ischemic perconditioning during valve replacement surgery

We previously found that remote ischemic perconditioning (RIPerc) was effective in attenuating myocardial injury during cardiac surgery. Given that microRNAs (miRs) act as an important player in ischemic/reperfusion (I/R) injury and apoptosis, this study aimed to investigate whether RIPerc reduces apoptosis in atrial myocardium and which apoptosis-related miRs are involved during valve replacement surgery. Here, we demonstrated that RIPerc inhibited apoptosis in atrial myocardium during cardiac ischemia and that 17 miRs showed at least a 1.5-fold change in expression after ischemia. Of the 17 miRs, 9 miRs, including miR-1, miR-21, miR-24, and miR-195, which are related to apoptosis, exhibited different expression patterns in the RIPerc group compared with the control. Using qRT-PCR and Western blotting, we demonstrated that miR-1 and miR-195 were downregulated and that their common putative target gene Bcl-2 was upregulated in the RIPerc group. However, the differences in miR-21 and miR-24 expression, together with programmed cell death 4 (PDCD4), which is the target gene of miR-21, were not significant. These findings provide some insight into the role of miRs in the cardioprotective effects induced by RIPerc.

Correlation of serum- and glucocorticoid-regulated kinase 1 expression with ischemia-reperfusion injury after heart transplantation

IRI of a transplanted heart may result in serious early and late disadvantageous effects such as increased allograft immunogenicity, primary graft dysfunction, and initiation of fibroproliferative cascades that compromise the survival of the recipient. Sgk-1 has recently been linked to cell growth and survival. It has been reported that through a renal transplantation model, Dexa increases Sgk-1 expression and therefore protects from renal IRI. In our current study, we aim to assess the expression of Sgk-1 and its protective effects on cardiomyocyte IRI after heart transplantation. Heart allograft model was performed from Wistar into Lewis, and isograft model was from Lewis into Lewis. Grafts were then harvested at one, six, 12, or 24 h post-transplantation for Sgk-1 expression analyses. In some groups, part donors were treated with Dexa 2 h prior at doses of 0.05, 0.5 and 2 mg/BWkg, respectively. Sgk-1 expression was markedly increased in grafted heart 6-12 h post-transplantation in both the allogenic and isogenic models. Immunostaining experiments confirmed that Sgk-1 was expressed in cardiomyocytes rather than infiltrated immune cells. Furthermore, Dexa treatment significantly increased Sgk-1 expression and the donor cardiomyocyte injury was greatly minimized by Dexa treatment. These results suggest that induction of Sgk-1 might explain some of the beneficial impact of corticosteroids in IRI and hence might have therapeutic implications.

Noncoding RNAs and myocardial fibrosis

Cardiac stress leads to remodelling of cardiac tissue, which often progresses to heart failure and death. Part of the remodelling process is the formation of fibrotic tissue, which is caused by exaggerated activity of cardiac fibroblasts leading to excessive extracellular matrix production within the myocardium. Noncoding RNAs (ncRNAs) are a diverse group of endogenous RNA-based molecules, which include short (∼22 nucleotides) microRNAs and long ncRNAs (of >200 nucleotides). These ncRNAs can regulate important functions in many cardiovascular cells types. This Review focuses on the role of ncRNAs in cardiac fibrosis; specifically, ncRNAs as therapeutic targets, factors for direct fibroblast transdifferentation, their use as diagnostic and prognostic markers, and their potential to function as paracrine modulators of cardiac fibrosis and remodelling.

MicroRNA-92a inhibition attenuates hypoxia/reoxygenation-induced myocardiocyte apoptosis by targeting Smad7

Background

MicroRNAs (miRNAs) regulate a lot of physiological and pathological processes, including myocardial ischemia/reperfusion. Recent studies reported that knockdown of miR-92a could attenuate ischemia/reperfusion-induced myocardial injury. In the present study, we examined the potential anti-apoptotic effects of miR-92a in a rat myocardiocyte cell line, and the possible role of Smad7 in such actions.

Methodology and Results

In a preliminary bioinformatic analysis, we identified SMAD family member 7 (Smad7) as a potential target for miR-92a. A luciferase reporter assay indeed demonstrated that miR-92a could inhibit Smad7 expression. Myocardial ischemia/reperfusion was simulated in rat H9c2 cells with 24-h hypoxia followed by 12-h reoxygenation. Prior to hypoxia/reoxygenation, cells were transfected by miR-92a inhibitor. In some experiments, cells were co-transfected with siRNA-Smad7. The miR-92a inhibitor dramatically reduced the release of lactate dehydrogenase and malonaldehyde, and attenuated cardiomyocyte apoptosis. The miR-92a inhibitor increased SMAD7 protein level and decreased nuclear NF-κB p65 protein. Effects of the miR-92a inhibitor were attenuated by co-transfection with siRNA-Smad7.

Conclusion

Inhibiting miR-92a can attenuate myocardiocyte apoptosis induced by hypoxia/reoxygenation by targeting Smad7.