Mild hypothermia pretreatment protects hepatocytes against ischemia reperfusion injury via down-regulating miR-122 and IGF-1R/AKT pathway

TIM proteins and microRNAs: distinct impact and promising interactions on transplantation immunity

Achieving sustained activity and tolerance in of allogeneic grafts after post-transplantation remains a substantial challenge. The response of the immune system to "non-self" MHC-antigenic peptides initiates a crucial phase, wherein blocking positive co-stimulatory signals becomes imperative to ensure graft survival and tolerance. MicroRNAs (miRNAs) inhibit mRNA translation or promote mRNA degradation by complementary binding of mRNA seed sequences, which ultimately affects protein synthesis. These miRNAs exhibit substantial promise as diagnostic, prognostic, and therapeutic candidates for within the realm of solid organ transplantations. Current research has highlighted three members of the T cell immunoglobulin and mucin domain (TIM) family as a novel therapeutic avenue in transplantation medicine and alloimmunization. The interplay between miRNAs and TIM proteins has been extensively explored in viral infections, inflammatory responses, and post-transplantation ischemia-reperfusion injuries. This review aims to elucidate the distinct roles of miRNAs and TIM in transplantation immunity and delineate their interdependent relationships in terms of targeted regulation. Specifically, this investigation sought seeks to uncover the potential of miRNA interaction with TIM, aiming to induce immune tolerance and bolster allograft survival after transplantation. This innovative strategy holds substantial promise in for the future of transplantation science and practice.

Inflammatory setting, therapeutic strategies targeting some pro-inflammatory cytokines and pathways in mitigating ischemia/reperfusion-induced hepatic injury: a comprehensive review

Ischemia/reperfusion injury (IRI) is a key determining agent in the pathophysiology of clinical organ dysfunction. It is characterized by an aseptic local inflammatory reaction due to a decrease in blood supply, hence deprivation of dependent oxygen and nutrients. In instances of liver transplantation, this injury may have irreversible implications, resulting in eventual organ rejection. The deterioration associated with IRI is affected by the hepatic health status and various factors such as alterations in metabolism, oxidative stress, and pro-inflammatory cytokines. The primary cause of inflammation is the initial immune response of pro-inflammatory cytokines, while Kupffer cells (KFCs) and neutrophil-produced chemokines also play a significant role. Upon reperfusion, the activation of inflammatory responses can elicit further cellular damage and organ dysfunction. This review discusses the interplay between chemokines, pro-inflammatory cytokines, and other inflammatory mediators that contribute to the damage to hepatocytes and liver failure in rats following IR. Furthermore, it delves into the impact of anti-inflammatory therapies in safeguarding against liver failure and hepatocellular damage in rats following IR. This review investigates the correlation between cytokine factors and liver dysfunction via examining databases, such as PubMed, Google Scholar, Science Direct, Egyptian Knowledge Bank (EKB), and Research Gate.

Mild hypothermia alleviates oxygen−glucose deprivation/reperfusion-induced apoptosis by inhibiting ROS generation, improving mitochondrial dysfunction and regulating DNA damage repair pathway in PC12 cells

The brain ischemia/reperfusion (I/R) injury has a great impact on human life and property safety. As far as we know, mild hypothermia (MH) is an effective measure to reduce neuronal injury after I/R. However, the precise mechanism is not extremely clear. The purpose of this study was to investigate whether mild therapeutic hypothermia can play a protective role in nerve cells dealing with brain I/R injury and explore its specific mechanism in vitro. A flow cytometer, cell counting kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) release assay were performed to detect apoptotic rate of cells, cell viability and cytotoxicity, respectively, reactive oxygen species (ROS) assay kit, JC-1 fluorescent methods, immunofluorescence and western blot were used to explore ROS, mitochondrial transmembrane potential (^Δψm), mitochondrial permeability transition pore (MPTP) and protein expression, respectively. The result indicated that the cell activity was decreased, while the cytotoxicity and apoptosis rate were increased after treating with oxygen-glucose deprivation/reperfusion (OGD/R) in PC12 cells. However, MH could antagonize this phenomenon. Interestingly, treating with OGD/R increased the release of ROS and the transfer of Cytochrome C (Cyt-C) from mitochondria to cytoplasm. In addition, it up-regulated the expression of γH2AX, Bax and Clv-caspase3, down-regulated the expression of PCNA, Rad51 and Bcl-2, and inhibited the function of mitochondria in PC12 cells. Excitingly, the opposite trend was observed after MH treatment. Therefore, our results suggest that MH protects PC12 cells against OGD/R-induced injury with the mechanism of inhibiting cell apoptosis by reducing ROS production, improving mitochondrial function, reducing DNA damage, and enhancing DNA repair.

Mild hypothermia ameliorates hepatic ischemia reperfusion injury by inducing RBM3 expression

Liver ischemia reperfusion injury (IRI) is a serious complication of certain liver surgeries, and it is difficult to prevent. As a potential drug-free treatment, mild hypothermia has been shown to promote positive outcomes in patients with IRI. However, the protective mechanism remains unclear. We established in vivo and in vitro models of hepatic ischemia reperfusion (IR) and mild hypothermia pretreatment. Hepatocytes were transfected with RNA-binding motif protein 3 (RBM3) overexpression plasmids, and IR was performed. Cell, culture medium, blood and tissue samples were collected to assess hepatic injury, oxidative stress, apoptosis and changes in RBM3 expression in the liver. Upregulation of RBM3 expression by mild hypothermia reduced the aminotransferase release, liver tissue injury and mitochondrial injury induced by liver IR. Hepatic IR-induced p38 and c-Jun N-terminal kinase (JNK) signaling pathway activation, oxidative stress injury and apoptosis could be greatly reversed by mild hypothermia. Overexpression of RBM3 mimicked the hepatoprotective effect of mild hypothermia. Mild hypothermia protects the liver from ischemia reperfusion-induced p38 and JNK signaling pathway activation, oxidative stress injury and apoptosis through the upregulation of RBM3 expression.

Novel Targets and Therapeutic Strategies to Protect Against Hepatic Ischemia Reperfusion Injury

Hepatic ischemia reperfusion injury (IRI), a fascinating topic that has drawn a lot of interest in the last few years, is a major complication caused by a variety of clinical situations, such as liver transplantation, severe trauma, vascular surgery, and hemorrhagic shock. The IRI process involves a series of complex events, including mitochondrial deenergization, metabolic acidosis, adenosine-5'-triphosphate depletion, Kupffer cell activation, calcium overload, oxidative stress, and the upregulation of pro-inflammatory cytokine signal transduction. A number of protective strategies have been reported to ameliorate IRI, including pharmacological therapy, ischemic pre-conditioning, ischemic post-conditioning, and machine reperfusion. However, most of these strategies are only at the stage of animal model research at present, and the potential mechanisms and exact therapeutic targets have yet to be clarified. IRI remains a main cause of postoperative liver dysfunction, often leading to postoperative morbidity or even mortality. Very recently, it was reported that the activation of peroxisome proliferator-activated receptor γ (PPARγ), a member of a superfamily of nuclear transcription factors activated by agonists, can attenuate IRI in the liver, and FAM3A has been confirmed to mediate the protective effect of PPARγ in hepatic IRI. In addition, non-coding RNAs, like LncRNAs and miRNAs, have also been reported to play a pivotal role in the liver IRI process. In this review, we presented an overview of the latest advances of treatment strategies and proposed potential mechanisms behind liver IRI. We also highlighted the role of several important molecules (PPARγ, FAM3A, and non-coding RNAs) in protecting against hepatic IRI. Only after achieving a comprehensive understanding of potential mechanisms and targets behind IRI can we effectively ameliorate IRI in the liver and achieve better therapeutic effects.

MicroRNA-32-5p attenuates cerebral ischemia/reperfusion injuries by modulating the phosphatase and tensin homologous protein

Non-coding RNAs have recently attracted much attention with the potential in the treatment of cerebral ischemia/reperfusion (I/R) injuries. In this study, we investigated the role of miR-32-5p in cerebral I/R injuries by using oxygen-glucose deprivation/reperfusion (OGD/R) PC12 cells and middle cerebral artery occlusion/reperfusion (MCAO/R) rats. The expression of genes and proteins were detected by RT-qPCR and Western blot, respectively. The function of OGD/R PC12 cells was detected using MTT assay and flow cytometry analysis. The influences of MCAO/R on rats was evaluated by measuring the infarct volume and brain water content. Bioinformatics analysis and luciferase gene reporter assay were used to identify the relationship between miR-32-5p and PTEN. The results showed that miR-32-5p had neuroprotective effects on OGD/R induced PC12 cells and MCAO/R injured rats' brain. The level of miR-32-5p was significantly reduced after OGD/R. Overexpression of miR-32-5p significantly reduced MCAO/R-induced brain damages in rats. Moreover, PTEN was found to be a target of miR-32-5p, and overexpression of PTEN attenuated the effects of miR-32-5p overexpression on cerebral I/R injuries. In addition, miR-32-5p was able to activate PI3K/AKT signaling by inhibiting PTEN. In conclusion, miR-32-5p prevents brain I/R injuries through modulating PTEN/PI3K/AKT signaling pathway.

Overexpression of miR-122 promotes apoptosis of dermal papilla cells by directly targeting IGF1R in androgenetic alopecia

Androgenetic alopecia (AGA) is the most common pattern of hair loss resulting from the effects of androgen on hair follicle. MicroRNAs (miRs) serve imperative roles in the regulation of many biological processes of hair follicle. However, the exact molecular mechanism of AGA remains to be elucidated. In the present study, we found miR-122, which is mainly recognized as a tumor suppressor, was highly overexpressed in the bulb of balding HFs in comparison with non-balding ones in AGA. Moreover, miR-122 induces apoptosis of human dermal papilla cells (hDPCs) with miR-122 mimics in vitro, and the expression of insulin-like growth factor 1 receptor (IGF1R) in hDPCs was reduced following upregulation of miR-122. Mechanistically, dual luciferase reporter assay confirmed that miR-122 directly targeted the 3'-untranslated region of IGF1R.These findings suggested that upregulation of miR-122 induces apoptosis, potentially via the repression of IGF1R in hDPCs of AGA, providing a novel insight into the potential pathological mechanism of miR-122 in AGA DPCs. This article is protected by copyright. All rights reserved.

Potential roles for microRNAs in facilitating physiological adaptation to low-temperature stress in Penaeus vannamei

Water temperature is one of the most common physiological stressors in aquaculture. Previous studies demonstrate that organisms require miRNA activity for survival in various unfavourable environmental conditions. However, the detailed role of miRNA in response to low-temperature stress is still unclear. This study was conducted to construct a comprehensive miRNA dataset for the Penaeus vannamei after low-temperature stress. A total of 329 known miRNAs and 60 putative novel miRNAs were identified. Among them, 17 miRNAs were identified with the most significant differences, and they were found to be involved in stimulation or stress processes. The main enriched target pathways of the 17 miRNAs were the Hippo signalling pathway, autophagy, apoptosis and MAPK signalling. In addition, all the 17 miRNAs identified were up-regulated, suggesting that miRNA by inhibiting the expression of target genes constitutes an effective strategy for Penaeus vannamei to cope with low-temperature stress. The 35-putative target of the 17 miRNAs was related to apoptosis and autophagy-related proteins, such as Pxt, DRAM2, cytochrome c, ATG2B, JNK, ATG4 and API5. The analysis of miRNA expression profiles contributes to the understanding of the molecular mechanisms of low-temperature tolerance in Penaeus vannamei. This study's findings enrich current miRNA resources and offer the possibility to validate the involvement of 17 miRNAs in the response of shrimp to low-temperature stress.

Effects of non-drug treatment on liver cells apoptosis during hepatic ischemia-reperfusion injury

Hepatic ischemia reperfusion injury (HIRI) is an important cause of liver dysfunction after liver transplantation for the patients suffered from fatty liver, non-alcoholic cirrhosis, or liver cancer. It is closely related to liver cells apoptosis. Therefore, how to maintain the stable state of cell apoptosis is important to protect the liver from HIRI. Drug treatment basically applies some active substances directly or indirectly, reducing HIRI. But their toxic side effects limit the clinical applications. Differently, non-drug treatment means making use of other kinds of measures to reduce the damage, such as non-pharmaceutical preparations, surgical methods, inhalation or perfusion gas, and so on. Non-drug treatments have been shown to balance cell apoptosis and reduce liver damage during HIRI. This review summarized the progresses in the roles of non-drug treatments on liver cells apoptosis during HIRI in recent years, focusing on apoptosis inducing factors, its signal transduction pathway, and downstream molecules, etc., expecting to elucidate non-drug treatments of anti-HIRI more systematically.

Mild hypothermia pretreatment extenuates liver ischemia-reperfusion injury through Rab7-mediated autophagosomes-lysosomes fusion

Liver ischemia-reperfusion (IR) injury is an unavoidable pathological process in transplantation, closely related to poor prognosis. To date, there has been no clear therapeutic measure. We previously reported that mild hypothermia (MH), a widely used therapy, can exert significant protective effect against liver IR injury. Among the multiple mechanisms underlying the therapeutic effect of MH, autophagy flux drew our special attention. In this study, we evaluated the role of autophagy flux in IR injury and thereby explored the relationship between MH and autophagy flux in IR injury. We developed in vivo and in vitro models for hepatic IR injury. By autophagy flux assay with Western blotting and immunofluorescence, we found that MH restricts heavy accumulation of autophagosomes (APs) during IR injury. Activation and blocking of the autophagy flux unraveled that accumulation of APs further aggravated IR injury. Further, MH reduces APs accumulation to restore autophagy flux by regulating the fusion of APs and lysosomes. Besides, MH upregulated the level of Rab7 protein expression that was seriously impaired during IR injury. Inhibition of Rab7 expression increased apoptosis of liver cells and reduced the degree of overlap between APs and lysosomes. The results were reversed upon activation of Rab7. In conclusion, MH can alleviate liver IR injury by regulating the Rab7-mediated APs-lysosomes fusion that reduces APs accumulation. This can provide a theoretical basis for the further application of MH in related clinical diseases.

MiR-122-5p knockdown protects against APAP-mediated liver injury through up-regulating NDRG3

MiR-122-5p serves as a novel biomarker for drug-induced liver injury (DILI), but its function in DILI remains unclear. The present study, therefore, explored the function and potential mechanism of miR-122-5p in DILI. Sprague-Dawley (SD) rats were treated with miR-122-5p antagomir, and then DILI was induced in the rats by acetaminophen (APAP). To determine the effect of miR-122-5p on DILI in vivo, liver injury was examined by HE staining and TUNEL assays, and the levels of serum ALT and AST were determined using an automated clinical chemistry analyzer. To further reveal the mechanism of miR-122-5p in DILI, THLE-2 (normal liver cell line) cells were transfected with miR-122-5p mimic and inhibitor, NDRG3, and siNDRG3, and then injured by APAP. The relationship between miR-122-5p and NDRG3 was determined by TargetScan, luciferase reporter assay, and Western blot. The viability and apoptosis of THLE-2 cells were detected by CCK-8 and flow cytometry, respectively. The levels of mRNA and protein in vivo and in vitro were measured by qRT-PCR and Western blot, respectively. APAP induced liver injury and increased the levels of ALT, AST, and miR-122-5p in DILI rats. However, these effects of APAP were attenuated by miR-122-5p antagomir. MiR-122-5p negatively regulated NDRG3 expression. APAP decreased cell viability, apoptosis resistance, and Bcl-w and Bcl-2 levels whereas increased Bax level in THLE-2 cells. However, these effects of APAP on THLE-2 cells were promoted by miR-122-5p up-regulation but inhibited by miR-122-5p knockdown. MiR-122-5p knockdown protects against APAP-mediated liver injury through up-regulating NDRG3.

Non-coding RNAs participate in the ischemia-reperfusion injury

Ischemia, being defined as blood supply deficiency is involved in the pathogenesis of a number of life-threatening conditions such as myocardial infarction and cerebral stroke. Assessment of the molecular pathology of these conditions has led to identification of the role of reperfusion in induction and aggravation of tissue injury and necrosis. Thus, the term "ischemia/ reperfusion (I/R) injury" has been introduced. This process involves aberrant regulation of the mitochondrial function, apoptotic and autophagic pathways and signal transducers. More recently, non-coding RNAs including long non-coding RNAs (lncRNAs) ad microRNAs (miRNAs) have been shown to influence I/R injury. Animal studies and clinical investigations have shown up-/down-regulation of tens of lncRNAs and miRNAs in this process. In the current study, we summarize the role of these transcripts in the pathophysiology of I/R injury and their potential as biomarkers for detection of extent of tissue injury.

Mild Hypothermia Attenuates Hepatic Ischemia-Reperfusion Injury through Regulating the JAK2/STAT3-CPT1a-Dependent Fatty Acid β-Oxidation

Hepatic ischemia–reperfusion (IR) injury is a clinical issue that can result in poor outcome and lacks effective therapies at present. Mild hypothermia (32–35°C) is a physiotherapy that has been reported to significantly alleviate IR injury, while its protective effects are attributed to multiple mechanisms, one of which may be the regulation of fatty acid β-oxidation (FAO). The aim of the present study was to investigate the role and underlying mechanisms of FAO in the protective effects of mild hypothermia. We used male mice to establish the experimental models as previously described. In brief, before exposure to in situ ischemia for 1 h and reperfusion for 6 h, mice received pretreatment with mild hypothermia for 2 h and etomoxir (inhibitor of FAO) or leptin (activator of FAO) for 1 h, respectively. Then, tissue and blood samples were collected to evaluate the liver injury, oxidative stress, and changes in hepatic FAO. We found that mild hypothermia significantly reduced the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury. In addition, the expression of the rate-limiting enzyme (CPT1a) of hepatic FAO was downregulated almost twofold by IR, while this inhibition could be significantly reversed by mild hypothermia. Experiments with leptin and etomoxir confirmed that activation of FAO could also reduce the hepatic enzyme levels and the score of hepatic pathological injury, hepatocyte apoptosis, oxidative stress, and mitochondrial injury induced by IR, which had the similar effects to mild hypothermia, while inhibition of FAO had negative effects. Furthermore, mild hypothermia and leptin could promote the phosphorylation of JAK2/STAT3 and upregulate the ratio of BCL-2/BAX to suppress hepatocyte apoptosis. Thus, we concluded that FAO played an important role in hepatic IR injury and mild hypothermia attenuated hepatic IR injury mainly via the regulation of JAK2/STAT3-CPT1a-dependent FAO.

Inhibition of MiR-122 Decreases Cerebral Ischemia-reperfusion Injury by Upregulating DJ-1-Phosphatase and Tensin Homologue Deleted on Chromosome 10 (PTEN)/Phosphonosinol-3 Kinase (PI3K)/AKT

BACKGROUND Ischemia-reperfusion injury is caused by a blood reperfusion injury in ischemic brain tissue, and usually occurs in the treatment stage of ischemic disease, which can aggravate brain tissue injury. MiR-122 is closely related to ischemia-reperfusion injury in the myocardium, kidney, and liver; however, the role in cerebral ischemia-reperfusion injury has not been established. MATERIAL AND METHODS In this study, cerebral ischemia-reperfusion injury was established in a rat model, and the control group was a sham-operated group. After ischemia-reperfusion injury for 6, 12, and 24 hours, brain tissue specimens were collected and the expression of miR-122 and DJ-1 were determined using quantitative real-time polymerase chain reaction. Flow cytometry was used to determine the reactive oxygen species (ROS) content. The modified Neurological Severity Score (mNSS) scale was used to evaluate the sensory and motor function defects of the rats. The malondialdehyde (MDA), superoxide dismutase (SOD), and enzyme activity were determined. The rats in the cerebral ischemia-reperfusion injury model were divided into 2 groups (antagomir-NC group and antagomir miR-122 group). Brain neuron RN-c cells were divided into the following 4 groups: antagomir-NC, antagomir miR-122, pIRES2-blank, and pIRES2-DJ-1. Seventy-two hours after transfection, ischemia-reperfusion treatment was carried out and conventional cultured RN-c cells were used as the control group. Flow cytometry was used to detect apoptosis and western blot was used to detect the expression of DJ-1, PTEN, AKT, and p-AKT. RESULTS The expression of miR-122 increased significantly in the process of ischemia-reperfusion damage after cerebral infarction, while the expression of DJ-1 decreased significantly. Downregulation of miR-122 significantly increased the expression of DJ-1, enhanced the activity of the PTEN/PI3K/AKT pathway, reduced cell apoptosis, and alleviated cerebral ischemia-reperfusion injury. CONCLUSIONS Inhibition of miR-122 can decrease cerebral ischemia-reperfusion injury by upregulating DJ-1-PTEN/PI3K/AKT pathway.

MicroRNA-101 inhibits autophagy to alleviate liver ischemia/reperfusion injury via regulating the mTOR signaling pathway

Liver ischemia/reperfusion injury (LIRI) is a common complication of liver surgery, and affects liver function post‑transplantation. However, the precise mechanism underlying LIRI has not yet been completely elucidated. Previous studies have demonstrated the involvement of a number of microRNAs (miRNAs/miRs) in liver pathophysiology. The objective of the present study was to determine the potential function and mechanism of miR‑101‑mediated regulation of autophagy in LIRI. Compared with the sham‑treated group, a significant decrease in miR‑101 and mechanistic target of rapamycin (mTOR) expression levels following ischemia/reperfusion (IR) were observed, along with an increased number of autophagosomes (P<0.001). The exogenous overexpression of miR‑101 has been demonstrated to inhibit autophagy during the LIRI response and the levels of mTOR and phosphorylated (p)‑mTOR expression are correspondingly elevated. However, compared with the miR‑NC group, miR‑101 silencing was associated with reduced mTOR and p‑mTOR levels and increased autophagy, as indicated by the gradual increase in the levels of the microtubule‑associated protein 1 light II (LC3II). The peak levels of LC3II were observed 12 h subsequent to reperfusion, which coincided with the lowest levels of miR‑101. In addition, inhibition of autophagy by 3‑methyladenine significant enhanced the protective effect of miR‑101 against LIRI, compared with the IR group (P<0.001). Altogether, miR‑101 attenuates LIRI by inhibiting autophagy via activating the mTOR pathway.

Hrd1 induces cardiomyocyte apoptosis via regulating the degradation of IGF-1R by sema3a

OBJECTIVE

To explore the underlying mechanisms of Hrd1/sema3a/IGF-1R on cardiomyocyte apoptosis.

METHODS

AMI model was established by the left-anterior descending coronary artery (LAD) ligation. The expressions of Hrd1, sema3a and IGF-1R were examined by western blot. The activity of caspase-3 and caspase-8 was measured using the corresponding activity detection kit. Cardiomyocyte apoptosis was detected by flow cytometry assay. Co-immunoprecipitation and ubiquitination assay were used to test the relationship among Hrd1, sema3a and IGF-1R.

RESULTS

Hrd1 expression and the activity of caspase-3 and caspase-8 were increased in cardiac tissues of AMI rats and hypoxia-induced cardiomyocytes, while IGF-1R expression was decreased. Hrd1 overexpression promoted IGF-1R degradation, whereas knockdown of sema3a suppressed this degradation. Moreover, knockdown of Hrd1 or sema3a could inhibit the decrease of IGF-1R expression induced by hypoxia, and reverse the enhanced activity of caspase-3 and caspase-8 and the increase of cardiomyocytes apoptosis induced by hypoxia, while si-IGF-1R countered these effects. In AMI rat experiments, interfering Hrd1 or sema3a reduced the infarct size and increased IGF-1R expression, but these could be abolished by si-IGF-1R.

CONCLUSION

Hrd1 might mediate the ubiquitination of IGF-1R through sema3a and then participate in the regulation of cardiomyocyte apoptosis.

Novel Targets for Treating Ischemia-Reperfusion Injury in the Liver

Liver ischemia-reperfusion injury (IRI) is a major complication of hemorrhagic shock, liver transplantation, and other liver surgeries. It is one of the leading causes for post-surgery hepatic dysfunction, always leading to morbidity and mortality. Several strategies, such as low-temperature reperfusion and ischemic preconditioning, are useful for ameliorating liver IRI in animal models. However, these methods are difficult to perform in clinical surgeries. It has been reported that the activation of peroxisome proliferator activated receptor gamma (PPARγ) protects the liver against IRI, but with unidentified direct target gene(s) and unclear mechanism(s). Recently, FAM3A, a direct target gene of PPARγ, had been shown to mediate PPARγ’s protective effects in liver IRI. Moreover, noncoding RNAs, including LncRNAs and miRNAs, had also been reported to play important roles in the process of hepatic IRI. This review briefly discussed the roles and mechanisms of several classes of important molecules, including PPARγ, FAM3A, miRNAs, and LncRNAs, in liver IRI. In particular, oral administration of PPARγ agonists before liver surgery or liver transplantation to activate hepatic FAM3A pathways holds great promise for attenuating human liver IRI.

Astaxanthin prevents ischemia-reperfusion injury of the steatotic liver in mice

Steatosis has a low tolerance against ischemia-reperfusion injury (IRI). To prevent IRI in the steatotic liver, we attempted to elucidate the protective effect of astaxanthin (ASTX) in the steatotic liver model by giving mice a methionine and choline-deficient high fat (MCDHF) diet. Levels of lipid peroxidation and apoptosis, the expression of inflammatory cytokines and heme oxygenase (HO)-1, in the liver were assessed. Reactive oxygen species (ROS), inflammatory cytokines, apoptosis-related proteins and members of the signaling pathway were also examined in isolated Kupffer cells and/or hepatocytes from the steatotic liver. ASTX decreased serum ALT and AST levels, the amount of TUNEL, F4/80, or 4HNE-positive cells and the mRNA levels of inflammatory cytokines in MCDHF mice by IRI. Moreover, HO-1 and HIF-1α, phosphorylation of Akt and mTOR expressions were increased by ASTX. The inflammatory cytokines produced by Kupffer, which were subjected to hypoxia and reoxygenation (HR), were inhibited by ASTX. Expressions of Bcl-2, HO-1 and Nrf2 in hepatocytes by HR were increased, whereas Caspases activation, Bax and phosphorylation of ERK, MAPK, and JNK were suppressed by ASTX. Pretreatment with ASTX has a protective effect and is a safe therapeutic treatment for IRI, including for liver transplantation of the steatotic liver.