microRNAs in liver and kidney ischemia reperfusion injury: insight to improve transplantation outcome

Nephroprotective and Antioxidant Effects of Jatropha dioica Extract Against Ischemia-Reperfusion Injury in Wistar Rats

Plant extracts with antioxidant activities have shown nephroprotection against IR injury. Jatropha dioica (Jd) possesses antioxidant activity. Our aim was to evaluate the effects of a hydroalcoholic Jd extract against IR injury in Wistar rats. Rats were divided into groups (n = 6): sham (SH); no toxicity (JdTox; 300 mg/kg/day of extract for 7 days); IR (on day 7 [I: 45 min/R: 24 h]); and Jd+IR (same treatment as JdTox; same surgical procedure as IR). AST and LDH were significantly lower in the JdTox. IR exhibited significantly higher CrS, BUN, and MDA compared with SH; Jd+IR showed reductions in these markers. GSH and SOD levels were significantly lower in IR compared with SH; an increase in these markers was observed in the Jd+IR. Histologically, IR showed significant increases in medullary tubular necrosis, medullary protein casts, and medullary vascular congestion compared with SH and JdTox. In Jd+IR, a significant decrease was observed only in medullary tubular necrosis. Therefore, the evaluated hydroalcoholic Jd extract dose showed no nephrotoxicity and hepatotoxicity. Jd extract pretreatment attenuated IR-induced renal injury, as evidenced by the improved serum markers of renal damage and oxidative stress.

Hydrogen sulfide plays an important role by regulating microRNA in different ischemia-reperfusion injury

MicroRNAs (miRNAs) are the short endogenous non-coding RNAs that regulate the expression of the target gene at posttranscriptional level through degrading or inhibiting the specific target messenger RNAs (mRNAs). MiRNAs regulate the expression of approximately one-third of protein coding genes, and in most cases inhibit gene expression. MiRNAs have been reported to regulate various biological processes, such as cell proliferation, apoptosis and differentiation. Therefore, miRNAs participate in multiple diseases, including ischemia-reperfusion (I/R) injury. Hydrogen sulfide (H2S) was once considered as a colorless, toxic and harmful gas with foul smelling. However, in recent years, it has been discovered that it is the third gas signaling molecule after carbon monoxide (CO) and nitric oxide (NO), with multiple important biological functions. Increasing evidence indicates that H2S plays a vital role in I/R injury through regulating miRNA, however, the mechanism has not been fully understood. In this review, we summarized the current knowledge about the role of H2S in I/R injury by regulating miRNAs, and analyzed its mechanism in detail.

The role of non-protein-coding RNAs in ischemic acute kidney injury

Acute kidney injury (AKI) is a condition characterized by a rapid decline in kidney function within a span of 48 hours. It is influenced by various factors including inflammation, oxidative stress, excessive calcium levels within cells, activation of the renin-angiotensin system, and dysfunction in microcirculation. Ischemia-reperfusion injury (IRI) is recognized as a major cause of AKI; however, the precise mechanisms behind this process are not yet fully understood and effective treatments are still needed. To enhance the accuracy of diagnosing AKI during its early stages, the utilization of innovative markers is crucial. Numerous studies suggest that certain noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), play a central role in regulating gene expression and protein synthesis. These ncRNAs are closely associated with the development and recovery of AKI and have been detected in both kidney tissue and bodily fluids. Furthermore, specific ncRNAs may serve as diagnostic markers and potential targets for therapeutic interventions in AKI. This review aims to summarize the functional roles and changes observed in noncoding RNAs during ischemic AKI, as well as explore their therapeutic potential.

A novel miRNA mimic attenuates organ injury after hepatic ischemia/reperfusion

INTRODUCTION

Extracellular cold-inducible RNA-binding protein (eCIRP) is a novel mediator of inflammation and tissue injury. It has been shown that miRNA 130b-3p acts as an endogenous inhibitor of eCIRP. Because RNA mimics are unstable after in vivo administration, we have chemically engineered miRNA 130b-3p mimic (named PS-OMe miR130) to improve its stability by protection from nuclease activity. We hypothesize that PS-OMe miR130 reduces eCIRP-mediated injury and inflammation in a murine model of hepatic ischemia/reperfusion (I/R), a model of sterile inflammation.

METHODS

Adult male mice underwent 70% hepatic ischemia for 60 minutes and 24-hour reperfusion. At the start of reperfusion, mice were treated intravenously with vehicle (phosphate-buffered saline) or PS-OMe miR130. Blood and liver tissue were collected after 24 hours for biochemical analysis. Apoptosis in the liver tissue was determined by transferase dUTP nick-end labeling assay.

RESULTS

After hepatic I/R, organ injury markers including aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase significantly decreased after PS-OMe miR130 treatment. Furthermore, histological analysis of liver sections demonstrated significantly less injury in PS-OMe miR130 treatment mice versus vehicle mice. In addition, tumor necrosis factor α mRNA, interleukin-1β mRNA, and neutrophil infiltration (myeloperoxidase activity and granulocyte receptor 1 immunohistochemistry) were significantly attenuated after PS-OMe miR130 treatment. Finally, apoptosis significantly decreased in liver tissue after treatment.

CONCLUSION

PS-OMe miR130 decreases eCIRP-mediated injury and inflammation in a murine model of hepatic I/R.

miR-27a-5p inhibits acute rejection of liver transplantation in rats by inducing M2 polarization of Kupffer cells through the PI3K/Akt pathway

Liver transplantation (LT), a major therapy for end-stage liver disease, is often associated with acute rejection (AR). MicroRNAs (miRNAs) have been implicated in AR-related gene regulation. In this experiment, the mechanism of miR-27a-5p in AR of LT was studied. Allotransplantation model (LEW-BN) and syngeneic transplantation model (LEW-LEW) of rat orthotopic liver transplantation (OLT) were established. miR-27a-5p was overexpressed in recipient rats 28 days before LT to detect its effects on LT pathology, liver function, and survival time. Kupffer cells (KCs) were isolated and treated with lipopolysaccharide (LPS) and miR-27a-5p overexpression. miR-27a-5p overexpression reduced lymphocyte numbers around portal areas and central veins after LT and mitigated degeneration of epithelial cells of the bile duct. Expression levels of IL-10 and TGF-β1 were increased while IL-12 was decreased. Liver function damage was alleviated and the survival time of rats with LT was prolonged. miR-27a-5p induced M2 polarization of rats with AR after LT and LPS-treated KCs in vitro and promoted activation of the PI3K/Akt pathway in KCs. Inhibition of the PI3K/Akt pathway averted induction of miR-27a-5p on M2 polarization of KCs. Taken together, miR-27a-5p inhibited AR after LT in rats by inducing M2 polarization of KCs through the PI3K/Akt pathway.

Molecular Mechanisms of Ischaemia-Reperfusion Injury and Regeneration in the Liver-Shock and Surgery-Associated Changes

Hepatic ischemia-reperfusion injury (IRI) represents a major challenge during liver surgery, liver preservation for transplantation, and can cause hemorrhagic shock with severe hypoxemia and trauma. The reduction of blood supply with a concomitant deficit in oxygen delivery initiates various molecular mechanisms involving the innate and adaptive immune response, alterations in gene transcription, induction of cell death programs, and changes in metabolic state and vascular function. Hepatic IRI is a major cause of morbidity and mortality, and is associated with an increased risk for tumor growth and recurrence after oncologic surgery for primary and secondary hepatobiliary malignancies. Therapeutic strategies to prevent or treat hepatic IRI have been investigated in animal models but, for the most part, have failed to provide a protective effect in a clinical setting. This review focuses on the molecular mechanisms underlying hepatic IRI and regeneration, as well as its clinical implications. A better understanding of this complex and highly dynamic process may allow for the development of innovative therapeutic approaches and optimize patient outcomes.

Hepatoprotective Role of Carvedilol against Ischemic Hepatitis Associated with Acute Heart Failure via Targeting miRNA-17 and Mitochondrial Dynamics-Related Proteins: An In Vivo and In Silico Study

Acute heart failure (AHF) is one of the most common diseases in old age that can lead to mortality. Systemic hypoperfusion is associated with hepatic ischemia–reperfusion injury, which may be irreversible. Ischemic hepatitis due to AHF has been linked to the pathogenesis of liver damage. In the present study, we extensively investigated the role of mitochondrial dynamics-related proteins and their epigenetic regulation in ischemic liver injury following AHF and explored the possible hepatoprotective role of carvedilol. The biochemical analysis revealed that the ischemic liver injury following AHF significantly elevated the activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) enzymes, the level of total and direct bilirubin, and the expression of hepatic mitogen-activated protein kinase (MAPK), dynamin-1-like protein (DNM1L), and hepatic miRNA-17. At the same time, it significantly reduced the serum albumin level, the activity of hepatic superoxide dismutase (SOD), and the expression of mitochondrial peroxisome proliferator-activated receptor-1α (PGC-1α), and mitofusin 2 (Mtf2). The histological examination of the liver tissue revealed degenerated hepatocytes. Interestingly, administration of carvedilol either prior to or after isoprenaline-induced AHF significantly improved the liver function and reversed the deterioration effect of AHF-induced ischemic hepatitis, as demonstrated by biochemical, immunohistochemical, and histological analysis. Our results indicated that the hepatoprotective effect of carvedilol in ameliorating hepatic ischemic damage could be attributed to its ability to target the mitochondrial dynamics-related proteins (Mtf2, DNM1L and PGC-1α), but also their epigenetic regulator miRNA-17. To further explore the mode of action of carvedilol, we have investigated, in silico, the ability of carvedilol to target dynamin-1-like protein and mitochondrial dynamics protein (MID51). Our results revealed that carvedilol has a high binding affinity (−14.83 kcal/mol) toward the binding pocket of DNM1L protein. In conclusion, our study highlights the hepatoprotective pharmacological application of carvedilol to attenuate ischemic hepatitis associated with AHF.

Friend or Foe: The Relativity of (Anti)oxidative Agents and Pathways

An element, iron, a process, the generation of reactive oxygen species (ROS), and a molecule, ascorbate, were chosen in our study to show their dual functions and their role in cell fate decision. Iron is a critical component of numerous proteins involved in metabolism and detoxification. On the other hand, excessive amounts of free iron in the presence of oxygen can promote the production of potentially toxic ROS. They can result in persistent oxidative stress, which in turn can lead to damage and cell death. At the same time, ROS—at strictly regulated levels—are essential to maintaining the redox homeostasis, and they are engaged in many cellular signaling pathways, so their total elimination is not expedient. Ascorbate establishes a special link between ROS generation/elimination and cell death. At low concentrations, it behaves as an excellent antioxidant and has an important role in ROS elimination. However, at high concentrations, in the presence of transition metals such as iron, it drives the generation of ROS. In the term of the dual function of these molecules and oxidative stress, ascorbate/ROS-driven cell deaths are not necessarily harmful processes—they can be live-savers too.

MicroRNAs: Novel Targets in Hepatic Ischemia–Reperfusion Injury

Hepatic ischemia–reperfusion injury (IRI) is one of the main factors for early allograft dysfunction (EAD), which may lead to graft rejection, graft loss, or shortened graft life in liver transplantation. Hepatic IRI appears to be inevitable during the majority of liver procurement and transportation of donor organs, resulting in a cascade of biological changes. The activation of signaling pathways during IRI results in the up- and downregulation of genes and microRNAs (miRNAs). miRNAs are ~21 nucleotides in length and well-characterized for their role in gene regulations; they have recently been used for therapeutic approaches in addition to their role as biomarkers for many diseases. miRNAs that are associated with hepatic IRI in in vitro and in vivo animal models are comprehensively summarized in this review. In those studies, the manipulation of miRNAs has been shown for the inhibition of aggravated immune response, reduction of apoptosis, stimulation of tissue repair, and enhancement of cell recovery to attenuate liver damage. Therefore, the utilization of liver-specific miRNA holds great potential as a therapeutic agent to improve early allograft dysfunction, hepatic injury, and patient outcome.

microRNA-9-5p protects liver sinusoidal endothelial cell against oxygen glucose deprivation/reperfusion injury

BACKGROUND

Maintenance of the function and survival of liver sinusoidal endothelial cells (LSECs) play a crucial role in hepatic ischemia/reperfusion (I/R) injury, a major cause of liver impairment during the surgical treatment. Emerging evidence indicates a critical role of microRNAs in I/R injury. This study aims to investigate whether miR-9-5p exerts a protective effect on LSECs.

METHODS

We transfected LSECs with miR-9-5p mimic or mimic NC. LSECs were treated with oxygen and glucose deprivation (OGD, 5% CO2, and 95% N2), followed by glucose-free Dulbecco's modified Eagle's medium (DMEM) medium for 6 h and high glucose (HG, 30 mmol/L glucose) DMEM medium for 12 h. The biological role of miR-9-5p in I/R-induced LSEC injury was determined.

RESULTS

In the in vitro model of OGD/HG injury in LSECs, the expression levels of miR-9-5p were significantly downregulated, and those of CXC chemokine receptor-4 (CXCR4) upregulated. LSEC I/R injury led to deteriorated cell death, enhanced oxidative stress, and excessive inflammatory response. Mechanistically, we showed that miR-9-5p overexpression significantly downregulated both mRNA and protein levels of CXCR4, followed by the rescue of LSECs, ameliorated inflammatory response, and deactivation of pro-apoptotic signaling pathways.

CONCLUSIONS

miR-9-5p promotes LSEC survival and inhibits apoptosis and inflammatory response in LSECs following OGD/HG injury via downregulation of CXCR4.