Protective effects of icariin-mediated SIRT1/FOXO3 signaling pathway on intestinal ischemia/reperfusion-induced acute lung injury

SIRT1: An Intermediator of Key Pathways Regulating Pulmonary Diseases

Silent information regulator type-1 (SIRT1), a nicotinamide adenine dinucleotide+-dependent deacetylase, is a member of the sirtuins family and has unique protein deacetylase activity. SIRT1 participates in physiological as well as pathophysiological processes by targeting a wide range of protein substrates and signalings. In this review, we described the latest progress of SIRT1 in pulmonary diseases. We have introduced the basic information and summarized the prominent role of SIRT1 in several lung diseases, such as acute lung injury, acute respiratory distress syndrome, chronic obstructive pulmonary disease, lung cancer, and aging-related diseases.

Icariin ameliorates LPS-induced acute lung injury in mice via complement C5a-C5aR1 and TLR4 signaling pathways

Acute lung injury (ALI) is an acute respiratory-related progressive disorder, which lacks specific pharmacotherapy. Icariin (ICA) has been shown to be effective in treating ALI. However, the targets and pharmacological mechanisms underlying the effects of ICA in the treatment of ALI are relatively lacking. Based on network pharmacology and molecular docking analyses, the gene functions and potential target pathways of ICA in the treatment of ALI were determined. In addition, the underlying mechanisms of ICA were verified by immunohistochemistry, immunofluorescence, quantitative Real-time PCR, and Western blot in LPS-induced ALI mice. The biological processes targeted by ICA in the treatment of ALI included the pathological changes, inflammatory response, and cell signal transduction. Network pharmacology, molecular docking, and in vivo experimental results revealed that ICA inhibited the complement C5a-C5aR1 axis, TLR4 mediated NF-κB, MAPK, and JAK2-STAT3 signaling pathways related gene and protein expressions, and decreased inflammatory cytokine, chemokine, adhesion molecule expressions, and mitochondrial apoptosis in LPS-induced ALI.

Cadmium-induced lung injury is associated with oxidative stress, apoptosis, and altered SIRT1 and Nrf2/HO-1 signaling; protective role of the melatonin agonist agomelatine

Cadmium (Cd) is a hazardous heavy metal extensively employed in manufacturing polyvinyl chloride, batteries, and other industries. Acute lung injury has been directly connected to Cd exposure. Agomelatine (AGM), a melatonin analog, is a drug licensed for treating severe depression. This study evaluated the effect of AGM against Cd-induced lung injury in rats. AGM was administered in a dose of 25 mg/kg/day orally, while cadmium chloride (CdCl2) was injected intraperitoneally in a dose of 1.2 mg/kg to induce lung injury. Pre-treatment with AGM remarkably ameliorated Cd-induced lung histopathological abrasions. AGM decreased reactive oxygen species (ROS) production, lipid peroxidation, suppressed NDAPH oxidase, and boosted the antioxidants. AGM increased Nrf2, GCLC, HO-1, and TNXRD1 mRNA, as well as HO-1 activity and downregulated Keap1. AGM downregulated Bax and caspase-3 and upregulated Bcl-2, SIRT1, and FOXO3 expression levels in the lung. In conclusion, AGM has a protective effect against Cd-induced lung injury via its antioxidant and anti-apoptotic effects mediated via regulating Nrf2/HO-1 and SIRT1/FOXO3 signaling.

Ferroptosis in organ ischemia-reperfusion injuries: recent advancements and strategies

Ferroptosis is a newly discovered type of regulated cell death participated in multiple diseases. Different from other classical cell death programs such as necrosis and apoptosis, ferroptosis involving iron-catalyzed lipid peroxidation is characterized by Fe2+ accumulation and mitochondria alterations. The phenomenon of oxidative stress following organ ischemia-reperfusion (I/R) has recently garnered attention for its connection to the onset of ferroptosis and subsequent reperfusion injuries. This article provides a comprehensive overview underlying the mechanisms of ferroptosis, with a further focus on the latest research progress regarding interference with ferroptotic pathways in organ I/R injuries, such as intestine, lung, heart, kidney, liver, and brain. Understanding the links between ferroptosis and I/R injury may inform potential therapeutic strategies and targeted agents.

Biomimetic Lung-Targeting Nanoparticles with Antioxidative and Nrf2 Activating Properties for Treating Ischemia/Reperfusion-Induced Acute Lung Injury

Ischemia/reperfusion (IR)-induced acute lung injury (ALI) has a high mortality rate. Reactive oxygen species (ROS) play a crucial role in causing cellular damage and death in IR-induced ALI. In this work, we developed a biomimetic lung-targeting nanoparticle (PC@MB) as an antioxidative lung protector for treating IR-induced ALI. PC@MBs showed excellent ROS scavenging and Nrf2 activation properties, along with a lung-targeting function through autologous cell membrane coating. The PC@MBs exhibited an impressive antioxidative and pulmonary protective role via redox homeostasis recovery through Nrf2 and heme oxygenase-1 activation. PC@MBs could maintain cell viability by effectively scavenging the intracellular ROS and restoring the redox equilibrium in the lesion. In the IR mouse model, the PC@MBs preferentially accumulated in the lung and distinctly repaired the pneumonic damage. Our strategy has the potential to offer a promising therapeutic paradigm for treating IR-induced ALI through the incorporation of different therapeutic mechanisms.

Role and mechanism of ferroptosis in acute lung injury

Ferroptosis is a new non-apoptotic cell death caused by the accumulation of dysregulated metabolism of ferric iron, amino acids or lipid peroxidation. Increasing studies suggest that ferroptosis is involved in the acute lung injury (ALI). This article aims to review the role of ferroptosis in ALI. ALI is a common respiratory disease and presents a high mortality rate. Inhibiting cell ferroptosis of lung improves the ALI. In addition, several signaling pathways are related to ferroptosis in ALI, involving in iron homeostasis, lipid peroxidation, and amino acid metabolism. Moreover, there are various key factors to regulate the occurrence of ferroptosis in ALI, such as ACSL4, NRF2, and P53. The ACSL4 promotes the ferroptosis, while the NRF2 alleviates the ferroptosis in ALI. The main effect of P53 is to promote ferroptosis. Accordingly, ferroptosis is involved in ALI and may be an important therapeutic target for ALI.

Targeting impaired nutrient sensing via the sirtuin pathway with novel compounds to prevent or treat dementia: A systematic review

BACKGROUND

Dementia is prevalent in aged populations and is associated with disability and distress for those affected. Therapeutic benefits of drugs targeting dementia are small. Impaired nutrient sensing pathways have been implicated in the pathogenesis of dementia and may offer a novel treatment target.

AIMS

This systematic review collated evidence for novel therapeutic compounds that modify nutrient sensing pathways, particularly the sirtuin pathway, in preventing cognitive decline or improving cognition in normal ageing, mild cognitive impairment (MCI), and dementia.

METHODS

PubMed, Embase and Web of Science databases were searched using key search terms. Articles were screened using Covidence systematic review software. The risk of bias was assessed using the Systematic Review Center for Laboratory animal Experimentation (SYRCLE)'s risk of bias tool for animal studies and Cochrane Risk of Bias tool v 2.0 for human studies.

RESULTS

Out of 3841 articles, 68 were included describing 38 different novel therapeutic compounds that modulate the nutrient sensing pathway via the sirtuin pathway. In animal models (58 studies), all investigated novel therapeutic compounds showed cognitive benefits. Ten studies were human intervention trials targeting normal ageing (1 study) and dementia populations (9 studies). Direct sirtuin (silent mating type information regulation 2 homolog) 1 (SIRT1) activators Resveratrol and Nicotinamide derivatives improved cognitive outcomes among human subjects with normal cognition and MCI.

CONCLUSION

Animal studies support that modulation of the sirtuin pathway has the potential to improve cognitive outcomes. Overall, there is a clear lack of translation from animal models to human populations.

Dihydroartemisinin ameliorates cerebral I/R injury in rats via regulating VWF and autophagy-mediated SIRT1/FOXO1 pathway

Dihydroartemisinin (DHA) has been found to inhibit the expression of von Willebrand factor (VWF), a marker of endothelial cell injury, but its mechanism in cerebral ischemia/reperfusion (I/R) injury remains obscure. In this study, I/R model was constructed through middle cerebral artery occlusion (MCAO) in rats, followed by DHA administration. The effect of DHA on rat cerebral I/R injury was investigated by 2,3,5-triphenyltetrazolium chloride staining, hematoxylin and eosin staining, TUNEL staining, and Western blot. Brain microvascular endothelial cells (BMVECs) isolated from newborn rats were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R), and then treated with DHA. The results showed that MCAO treatment induced infarction, nerve cell apoptosis, and brain tissue impairment in rats, which was mitigated by DHA. OGD/R inhibited viability and accelerated apoptosis of BMVECs, which was alleviated by DHA. I/R procedures or OGD/R up-regulated expressions of VWF, ATG7, Beclin1, and LC3-II/LC3-I ratio, while down-regulating Occludin, Claudin-5, ZO-1, P62, SIRT1, and FOXO1 expressions in vivo and in vitro; however, these effects of I/R procedures or OGD/R were offset by DHA. VWF overexpression reversed the above effects of DHA on OGD/R-induced BMVECs. In summary, DHA ameliorates cerebral I/R injury in rats by reducing VWF level and activating autophagy-mediated SIRT1/FOXO1 signaling pathway.

The forkhead box O3 (FOXO3): a key player in the regulation of ischemia and reperfusion injury

Forkhead box O3 is a protein encoded by the FOXO3 gene expressed throughout the body. FOXO3 could play a crucial role in longevity and many other pathologies, such as Alzheimer's disease, glioblastoma, and stroke. This study is a comprehensive review of the expression of FOXO3 under ischemia and reperfusion (IR) and the molecular mechanisms of its regulation and function. We found that the expression level of FOXO3 under ischemia and IR is tissue-specific. Specifically, the expression level of FOXO3 is increased in the lung and intestinal epithelial cells after IR. However, FOXO3 is downregulated in the kidney after IR and in the skeletal muscles following ischemia. Interestingly, both increased and decreased FOXO3 expression have been reported in the brain, liver, and heart following IR. Nevertheless, these contribute to stimulating ischemia and reperfusion injury via the induction of inflammatory response, apoptosis, autophagy, mitophagy, pyroptosis, and oxidative damage. These results suggest that FOXO3 could play protective effects in some organs and detrimental effects in others against IR injury. Most importantly, these findings indicate that controlling FOXO3 expression, genetically or pharmacologically, could contribute to preventing or treating ischemia and reperfusion damage.

SRPK1 promotes sepsis-induced acute lung injury via regulating PI3K/AKT/FOXO3 signaling

OBJECTIVE

Sepsis is the most common cause of death in intensive care unit. Moreover, sepsis is the leading cause of acute lung injury (ALI). Serine-arginine protein kinase 1 (SRPK1) was demonstrated to promote the development of ALI. However, the potentials of SRPK1 in sepsis-induced ALI are still unknown. This study aimed to investigate the potentials of SRPK1 in sepsis-induced ALI and the underlying mechanisms.

METHODS

Cecal ligation and puncture (CLP) was performed to establish sepsis-induced ALI model in vivo. Primary human pulmonary microvascular endothelial cells (HPMECs) were exposed to lipopolysaccharide (LPS) to construct sepsis-induced ALI model in vitro. Gene expression was detected using western blot and qRT-PCR. The interaction between forkhead box O3 (FOXO3) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) was detected using luciferase and Chromatin immunoprecipitation (ChIP) assay. Cellular functions were CCK-8, colony formation, PI staining, and flow cytometry assay.

RESULTS

SRPK1 was downregulated in patients with sepsis-induced ALI. Overexpression of SRPK1 suppressed the pyroptosis of HPMECs as well as promoted cell proliferation. Additionally, SRPK1 overexpression alleviated sepsis-induced ALI in vivo. SRPK1 activated phosphatidylinositol3-kinase (PI3K) signaling pathways. Blocking the activation of PI3K degraded the cellular functions of HPMECs. Moreover, FOXO3 transcriptionally inactivated NLRP3 and suppressed its mRNA and protein expression.

CONCLUSION

Taken together, SRPK1 suppressed sepsis-induced ALI via regulating PI3K/AKT/FOXO3/NLRP3 signaling. SRPK1 may be the potential biomarker for sepsis-induced ALI.

Nrf2 attenuates ferroptosis-mediated IIR-ALI by modulating TERT and SLC7A11

Acute lung injury (ALI) carries a mortality rate of ~50% and is a hot topic in the world of critical illness research. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a critical modulator of intracellular oxidative homeostasis and serves as an antioxidant. The Nrf2-related anti-oxidative stress is strongly associated with ferroptosis suppression. Meanwhile, telomerase reverse transcriptase (TERT), the catalytic portion of the telomerase protein, is reported to travel to the mitochondria to alleviate ROS. In our study, we found that TERT was significantly reduced in lung tissue of Nrf2^-/- mice in the model of intestinal ischemia/reperfusion-induced acute lung injury (IIR-ALI). In addition, MDA levels showed marked increase, whereas GSH and GPX4 levels fell drastically in ALI models. Moreover, typical-related structural changes were observed in the type II alveolar epithelial cells in the IIR model. We further employed the scanning transmission X-ray microscopy (STXM) to examine Fe levels and distribution within cells. Based on our observations, massive aggregates of Fe were found in the MLE-12 cells upon OGD/R (oxygen and glucose deprivation/reperfusion) induction. Additionally, Nrf2 silencing dramatically reduced TERT and SLC7A11 levels, and further exacerbated cellular injuries. In contrast, TERT-overexpressing cells exhibited marked elevation in SLC7A11 levels and thereby inhibited ferroptosis. Collectively, these data suggest that Nrf2 can negatively regulate ferroptosis via modulation of TERT and SLC7A11 levels. The conclusion from this study brings insight into new candidates that can be targeted in future IIR-ALI therapy.

Sesamin Protects against and Ameliorates Rat Intestinal Ischemia/Reperfusion Injury with Involvement of Activating Nrf2/HO-1/NQO1 Signaling Pathway

Intestinal ischemia-reperfusion (I/R) may induce cell/tissue injuries, leading to multiple organ failure. Based on our preexperiments, we proposed that sesamin could protect against and ameliorate intestinal I/R injuries and related disorders with involvement of activating Nrf2 signaling pathway. This proposal was evaluated using SD intestinal I/R injury rats in vivo and hypoxia/reoxygenation- (H/R-) injured rat small intestinal crypt epithelial cell line (IEC-6 cells) in vitro. Sesamin significantly alleviated I/R-induced intestinal histopathological injuries and significantly reduced serum biochemical indicators ALT and AST, alleviating I/R-induced intestinal injury in rats. Sesamin also significantly reversed I/R-increased TNF-α, IL-6, IL-1β, and MPO activity in serum and MDA in tissues and I/R-decreased GSH in tissues and SOD in both tissues and IEC-6 cells, indicating its anti-inflammatory and antioxidative stress effects. Further, sesamin significantly decreased TUNEL-positive cells, downregulated the increased Bax and caspase-3 protein expression, upregulated the decreased protein expression of Bcl-2 in I/R-injured intestinal tissues, and significantly reversed H/R-reduced IEC-6 cell viability as well as reduced the number of apoptotic cells among H/R-injured IEC-6 cell, showing antiapoptotic effects. Activation of Nrf2 is known to ameliorate tissue/cell injuries. Consistent with sesamin-induced ameliorations of both intestinal I/R injuries and H/R injuries, transfection of Nrf2 cDNA significantly upregulated the expression of Nrf2, HO-1, and NQO1, respectively. On the contrary, either Nrf2 inhibitor (ML385) or Nrf2 siRNA transfection significantly decreased the expression of these proteins. Our results suggest that activation of the Nrf2/HO-1/NQO1 signaling pathway is involved in sesamin-induced anti-inflammatory, antioxidative, and antiapoptotic effects in protection against and amelioration of intestinal I/R injuries.

Evaluation of Protective Effects of Curcumin and Nanocurcumin on Aluminium Phosphide‑Induced Subacute Lung Injury in Rats: Modulation of Oxidative Stress through SIRT1/FOXO3 Signalling Pathway

OBJECTIVE

Aluminum phosphide (AlP) is widely used to protect stored food products and grains from pests and rodents. The availability of AlP, especially in Asian countries it has become a desirable factor to commit suicide. The phosphine produced from ALP is a very reactive radical and a respiratory inhibitor that causes oxidative damage. There is no dedicated antidote or effective drug to manage AlP-induced lung toxicity. The present study aims to evaluate and compare the protective effects of curcumin and nanocurcumin on ALP‑induced subacute lung injury and determine the underlying mechanism.

METHODS

Rats were exposed to AlP (2 mg/kg/day, orally)+curcumin or nanocurcumin (100 mg/kg/day, orally) for 7 days. Then rats were anesthetized and lung tissues were collected. Oxidative stress biomarkers, genes expression of antioxidant enzymes, participated genes in the SIRT1/FOXO3 pathway, and lung histopathology were assessed by biochemical and ELISA methods, Real-Time PCR analysis, and H&E staining.

RESULTS

Curcumin and nanocurcumin produced a remarkable improvement in AlP-induced lung damage through reduction of MDA, induction of antioxidant capacity (TAC, TTG) and antioxidant enzymes (CAT, GPx), modulation of histopathological changes, and up-regulation of genes expression of SIRT1, FOXO3, FOXO1 in lung tissue.

CONCLUSION

Nanocurcumin had a significantly more protective effect than curcumin to prevent AlP-induced lung injury via inhibition of oxidative stress. Nanocurcumin could be considered a suitable therapeutic choice for AlP poisoning.

Cellular Signal Transduction Pathways Involved in Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (II/R) injury is a common type of tissue and organ injury, secondary to intestinal and mesenteric vascular diseases. II/R is characterized by a high incidence rate and mortality. In the II/R process, intestinal barrier function is impaired and bacterial translocation leads to excessive reactive oxygen species, inflammatory cytokine release, and even apoptosis. A large number of inflammatory mediators and oxidative factors are released into the circulation, leading to severe systemic inflammation and multiple organ failure of the lung, liver, and kidney. Acute lung injury (ALI) is the most common complication, which gradually develops into acute respiratory distress syndrome and is the main cause of its high mortality. This review summarizes the signal transduction pathways and key molecules in the pathophysiological process of ALI induced by II/R injury and provides a new therapeutic basis for further exploration of the molecular mechanisms of ALI induced by II/R injury. In particular, this article will focus on the biomarkers involved in II/R-induced ALI.

Dexmedetomidine hydrochloride inhibits hepatocyte apoptosis and inflammation by activating the lncRNA TUG1/miR-194/SIRT1 signaling pathway

BACKGROUND

Liver injury seriously threatens the health of people. Meanwhile, dexmedetomidine hydrochloride (DEX) can protect against liver injury. However, the mechanism by which Dex mediates the progression of liver injury remains unclear. Thus, this study aimed to investigate the function of DEX in oxygen and glucose deprivation (OGD)-treated hepatocytes and its underlying mechanism.

METHODS

In order to investigate the function of DEX in liver injury, WRL-68 cells were treated with OGD. Cell viability was measured by MTT assay. Cell apoptosis was detected by flow cytometry. Inflammatory cytokines levels were measured by ELISA assay. The interaction between miR-194 and TUG1 or SIRT1 was detected by dual-luciferase reporter. Gene and protein levels were measured by qPCR or western blotting.

RESULTS

DEX notably reversed OGD-induced inflammation and apoptosis in WRL-68 cell. Meanwhile, the effect of OGD on TUG1, SIRT1 and miR-194 expression in WRL-68 cells was reversed by DEX treatment. However, TUG1 knockdown or miR-194 overexpression reversed the function of DEX in OGD-treated WRL-68 cells. Moreover, TUG1 could promote the expression of SIRT1 by sponging miR-194. Furthermore, knockdown of TUG1 promoted OGD-induced cell growth inhibition and inflammatory responses, while miR-194 inhibitor or SIRT1 overexpression partially reversed this phenomenon.

CONCLUSIONS

DEX could suppress OGD-induced hepatocyte apoptosis and inflammation by mediation of TUG1/miR-194/SIRT1 axis. Therefore, this study might provide a scientific basis for the application of DEX on liver injury treatment.

Depleting microRNA-146a-3p attenuates lipopolysaccharide-induced acute lung injury via up-regulating SIRT1 and mediating NF-κB pathway

OBJECTIVE

The role of microRNAs (miRs) in acute lung injury (ALI) has been discussed. This study is to uncover the effects of miR-146a-3p/Sirtuin-1 (SIRT1)/Nuclear factor-kappa B (NF-κB) axis on ALI.

METHODS

Human normal lung epithelial cell line BEAS-2B was exposed to lipopolysaccharide (LPS) to establish an in vitro model of ALI. NF-κB expression, cell activity, apoptosis, inflammatory factors, oxidative stress indices were detected in LPS-induced BEAS-2B cells after miR-146a-3p was down-regulated or SIRT1 was up-regulated. ALI rat model was established and the NF-κB expression, wet/dry weight (W/D) ratio, pathological changes, pneumonocyte apoptosis, inflammatory factors, oxidative stress indices were detected in ALI rats after miR-146a-3p was down-regulated or SIRT1 was up-regulated. The target relationship between miR-146a-3p and SIRT1 was confirmed.

RESULTS

Reduced SIRT1 and raised miR-146a-3p  were found in LPS-induced BEAS-2B cells and ALI rats. SIRT1-overexpressing or  miR-146a-3p-underexpressing up-regulated NF-κB expression, promoted viability and inhibited apoptosis of LPS-induced BEAS-2B cells in vitro, and increased NF-κB expression, down-regulated the W/D ratio, attenuated pathological changes, suppressed apoptosis, and alleviated inflammatory response and oxidative stress in the lung of ALI rats. MiR-146a-3p directly binds to the 3'UTR of SIRT1 mRNA.

CONCLUSION

Depleting miR-146a-3p improves ALI through up-regulating SIRT1 and mediating NF-κB pathway.

The effect of tropisetron on oxidative stress, SIRT1, FOXO3a, and claudin-1 in the renal tissue of STZ-induced diabetic rats

Tropisetron is a 5-HT3 receptor antagonist that exerts protective effect against DN. The aim of this study was to investigate the possible molecular mechanisms associated with the renoprotective effects of tropisetron in STZ-induced diabetic rats. Animals were subdivided into 5 equal groups; control, tropisetron, diabetes, tropisetron + diabetes, and glibenclamide + diabetes (n = 7). For induction of type 1 diabetes, a single injection of STZ (55 mg/kg, i.p.) was administered to the animals. Diabetic rats were treated with tropisetron (3 mg/kg) and glibenclamide (1 mg/kg) for 2 weeks. According to the conducted analysis, diabetes led to renal dysfunction (reduction in glomerular filtration rate and urine urea and creatinine as well as elevation in plasma urea and creatinine) and abnormalities in antioxidant defense system (reduction in TAC and elevation in MDA), compared with the control group, which was prevented by tropisetron treatment. Reverse transcription-quantitative polymerase chain reaction and western blotting analysis demonstrated that SIRT1 gene expression decreased while FOXO3a and NF-κB gene expression as well as phosphorylated FOXO3a/total FOXO3a protein ratios and claudin-1 protein level increased in the kidney of diabetic rats compared with the control group. Herein, the results of this research showed that tropisetron treatment reversed these changes. Besides, all these changes were comparable with those produced by glibenclamide as a positive control. Hence, tropisetron ameliorated renal damage due to diabetic nephropathy possibly by suppressing oxidative stress and alteration of SIRT1, FOXO3a, and claudin-1 levels.

Nervilifordin F alleviates intestinal ischemia/reperfusion-induced acute lung injury via inhibiting inflammasome and mTOR pathway

Acute lung injury (ALI) is a life-threatening disorder with high rates of morbidity and mortality. Up to now, there are still no effective drugs for its therapies due to the complexity of its etiology and pathogenesis. In this present study, we investigated the protective effect of Nervilifordin F (NF) on ALI induced by intestinal ischemia/reperfusion (II/R) and its related mechanism. Firstly, the ALI model rats were induced through II/R, and treated with NF. Then, the pathological and cytokine level changes in the lung tissue of ALI rats were evaluated by hematoxylin and eosin and enzyme-linked immunosorbent assay (ELISA). The related genes expression level of mammalian target of rapamycin (mTOR) pathway and inflammasome were measured by real-time quantitative polymerase chain reaction (RT-qPCR), western blot and immunohistochemistry. Finally, the NF-protein complexes were predicted by SYBYL-X 2.0. The results indicated that NF can significant reduces the levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 and IL-1β, and inhibits the expression of inflammasome related genes (such as toll-like receptor 4 (TLR4), p65, NOD-like receptor protein 3 (NLRP3) and Caspase 1), thereby reduce inflammation in II/R-induced ALI rats. Moreover, NF can activate the expression of FK506 binding protein 25 (FKBP25) and down-regulate the expression of mTOR and p70 ribosomal protein S6 kinase 1 (p70S6K). In addition, molecular docking results showed that NF can be combined well with p70S6K, TLR4, mTOR and NLRP3, which further verified the inhibitory effect of NF on ALI inflammation. Therefore, the findings indicate that NF can alleviates II/R-induced inflammation of ALI rats by inhibiting inflammasome related genes and mTOR pathway, which expected to use as a potential drug for the treatment of ALI.

Nrf2 inhibits ferroptosis and protects against acute lung injury due to intestinal ischemia reperfusion via regulating SLC7A11 and HO-1

Acute lung injury (ALI) is a syndrome associated with a high mortality rate. Nrf2 is a key regulator of intracellular oxidation homeostasis that plays a pivotal role in controlling lipid peroxidation, which is closely related to the process of ferroptosis. However, the intrinsic effect of Nrf2 on ferroptosis remains to be investigated in ALI. We found that MDA expression increased while GSH and GPX4 decreased in ALI models. Furthermore, the characteristic mitochondrial morphological changes of ferroptosis appear in type II alveolar epithelial cells in IIR models. Additional pre-treatment of Fe and Ferrostatin-1 in ALI significantly aggravated or ameliorated the pathological injuries of lung tissue, pulmonary edema, lipid peroxidation, as well as promoted or prevented cell death, respectively. Knocking down Nrf2 notably decreased the expression of SLC7A11 and HO-1. Interference with SLC7A11 markedly increased Nrf2-HO-1 and dramatically attenuated cell death in OGD/R models. These findings indicate that ferroptosis can be inhibited by Nrf2 through regulating SLC7A11 and HO-1, which may provide a potential therapeutic strategy for IIR-ALI.

Targeting microRNAs as a Therapeutic Strategy to Reduce Oxidative Stress in Diabetes

Diabetes mellitus is a group of heterogeneous metabolic disorders characterized by chronic hyperglycaemia as a consequence of pancreatic β cell loss and/or dysfunction, also caused by oxidative stress. The molecular mechanisms involved inβ cell dysfunction and in response to oxidative stress are also regulated by microRNAs (miRNAs). miRNAs are a class of negative gene regulators, which modulate pathologic mechanisms occurring in diabetes and its complications. Although several pharmacological therapies specifically targeting miRNAs have already been developed and brought to the clinic, most previous miRNA-based drug delivery methods were unable to target a specific miRNA in a single cell type or tissue, leading to important off-target effects. In order to overcome these issues, aptamers and nanoparticles have been described as non-cytotoxic vehicles for miRNA-based drug delivery. These approaches could represent an innovative way to specifically target and modulate miRNAs involved in oxidative stress in diabetes and its complications. Therefore, the aims of this review are: (i) to report the role of miRNAs involved in oxidative stress in diabetes as promising therapeutic targets; (ii) to shed light onto the new delivery strategies developed to modulate the expression of miRNAs in diseases.

Histone acetylation and DNA methylation in ischemia/reperfusion injury

Ischemic/reperfusion (I/R) injury causes a series of serious clinical problems associated with high morbidity and mortality in various disorders, such as acute kidney injury (AKI), myocardial infarction, ischemic stroke, circulatory arrest, and peripheral vascular disease. The pathophysiology and pathogenesis of I/R injury is complex and multifactorial. Recent studies have revealed that epigenetic regulation is critically involved in the pathogenesis of I/R-induced tissue injury. In this review, we will sum up recent advances on the modification, regulation, and implication of histone modifications and DNA methylation in I/R injury-induced organ dysfunction. Understandings of I/R-induced epigenetic alterations and regulations will aid in the development of potential therapeutics.

Nicotinamide riboside has protective effects in a rat model of mesenteric ischaemia-reperfusion

Acute mesenteric ischaemia is a syndrome caused by inadequate blood flow through the mesenteric vessels, resulting in ischaemia and eventual gangrene of the bowel wall. Although relatively rare, it is a potentially life-threatening condition. The maintenance of haemodynamic stability, along with adequate oxygen saturation, and the correction of any electrolyte imbalance, are of the utmost importance. However, nicotinamide adenine dinucleotide (NAD) biosynthesis modulation by precursor introduction can also be a powerful tool for preventing injury. Nicotinamide riboside is a pyridine-nucleoside form of vitamin B3 that functions as a precursor to NAD+ . The present study investigated nicotinamide riboside's effect on endothelium functional state, microcirculation and intestinal morphology in acute mesenteric ischaemia and reperfusion. Mesenteric ischaemia was simulated after the adaptation period (15 minutes) by occluding the superior mesenteric artery for 60 minutes, followed by a reperfusion period of 30 minutes. The functional state of intestinal microcirculation was evaluated by laser Doppler flowmetry. Endothelial functional activity was studied by using wire myography. Intestinal samples were stained with haematoxylin and eosin for histological analysis. The results revealed that nicotinamide riboside protects the intestinal wall from ischaemia-reperfusion injury, as well as improving the relaxation function of mesenteric vessels. Nicotinamide riboside's protective effect in small intestine ischaemia-reperfusion can be used to reduce ischaemia-reperfusion injury, as well as to preserve intestinal grafts until transplant.

Icariin protects cardiomyocytes against ischaemia/reperfusion injury by attenuating sirtuin 1-dependent mitochondrial oxidative damage

BACKGROUND AND PURPOSE

Icariin, a major active ingredient in traditional Chinese medicines, is attracting increasing attention because of its unique pharmacological effects against ischaemic heart disease. The histone deacetylase, sirtuin-1, plays a protective role in ischaemia/reperfusion (I/R) injury, and this study was designed to investigate the protective role of icariin in models of cardiac I/R injury and to elucidate the potential involvement of sirtuin-1.

EXPERIMENTAL APPROACH

I/R injury was simulated in vivo (mouse hearts), ex vivo (isolated rat hearts) and in vitro (neonatal rat cardiomyocytes and H9c2 cells). Prior to I/R injury, animals or cells were exposed to icariin, with or without inhibitors of sirtuin-1 (sirtinol and SIRT1 siRNA).

KEY RESULTS

In vivo and in vitro, icariin given before I/R significantly improved post-I/R heart contraction and limited the infarct size and leakage of creatine kinase-MB and LDH from the damaged myocardium. Icariin also attenuated I/R-induced mitochondrial oxidative damage, decreasing malondialdehyde content and increasing superoxide dismutase activity and expression of Mn-superoxide dismutase. Icariin significantly improved mitochondrial membrane homeostasis by increasing mitochondrial membrane potential and cytochrome C stabilization, which further inhibited cell apoptosis. Sirtuin-1 was significantly up-regulated in hearts treated with icariin, whereas Ac-FOXO1 was simultaneously down-regulated. Importantly, sirtinol and SIRT1 siRNA either blocked icariin-induced cardioprotection or disrupted icariin-mediated mitochondrial homeostasis.

CONCLUSIONS AND IMPLICATIONS

Pretreatment with icariin protected cardiomyocytes from I/R-induced oxidative stress through activation of sirtuin-1 /FOXO1 signalling.

The effects of S-nitrosoglutathione on intestinal ischemia reperfusion injury and acute lung injury in rats: Roles of oxidative stress and NF-κB

BACKGROUND

Intestinal ischemia and reperfusion (I/R) induces oxidative stress, inflammatory response, and acute lung injury. S-nitrosoglutathione (GSNO), a nitric oxide donor, has been documented to have protective effects on experimental ischemia models.

AIM

The aim of this study was to examine the effect of GSNO on I/R-induced intestine and lung damage and detect the potential mechanisms emphasizing the protective role of GSNO.

METHODS

Intestinal I/R was induced by occluding the superior mesenteric artery for 30 min followed by reperfusion for 180 min. GSNO was administered intravenously before reperfusion period (0.25 mg/kg). The levels of lipid peroxidation, reduced glutathione, and myeloperoxidase (MPO), histopathological evaluation and immunohistochemical expressions of both nuclear factor KappaB (NF-κB) and inducible nitric oxide (iNOS) in intestine and lung tissues were assessed.

RESULTS

Histolopathologic evaluation demonstrated that intestinal I/R induced severe damages in the intestine and the lung tissues. Histopathological scores decreased with GSNO treatment. GSNO treatment reduced lipid peroxidation and MPO levels and inhibited expression of NF-κB and iNOS in the intestine.

CONCLUSION

Our results suggest that GSNO treatment may ameliorate the intestinal and lung injury in rats, at least in part, by inhibiting inflammatory response and oxidative stress.

Icariin protects against ischemia‑reperfusion injury in H9C2 cells by upregulating heat shock protein 20

Icariin (ICA) has been implicated in certain biological and pathological processes, including myocardial ischemia/reperfusion (I/R) injury. The aim of the present study was to investigate the role of ICA in I/R‑induced cardiomyocyte injury and the potential underlying mechanism. Cell proliferation and apoptosis of H9C2 cells was determined by cell counting kit‑8 and flow cytometry assays. In addition, reactive oxygen species (ROS) production in H9C2 cells was measured by flow cytometry. Reverse transcription‑quantitative polymerase chain reaction and western blot assay were performed to examine the expression levels of proteins, including HSP20, B‑cell lymphoma 2 (Bcl‑2), cytochrome complex (Cyt‑c), apoptotic protease activating factor 1 (APAF1), caspase‑9 andcaspase‑3, and the phosphorylation of Akt (p‑Akt) in H9C2 cells. The present results demonstrated that, compared with the control group, the I/R group demonstrated significantly reduced levels of HSP20 expression and cell proliferation, and increased apoptosis and ROS production in H9C2 cells. In parallel, the expression levels of Cyt‑c, APAF1, caspase‑9 and caspase‑3 were significantly increased in the I/R group, although Bcl‑2 and p‑Akt/Akt expression levels were decreased. Furthermore, compared with the I/R group, ICA treatment and/or HSP20 overexpression significantly improved cardiac function, as evidenced by promoted cell proliferation and inhibited apoptosis of H9C2 cells. The current study indicates that ICA exerts a cardioprotective effect against I/R injury, which is associated with the upregulation of HSP20.

Effect of sodium butyrate on small intestinal injury following intestinal ischemia-reperfusion in rats

AIM: To investigate the effect of sodium butyrate (BTR) on small intestinal injury following intestinal ischemia-reperfusion (I/R) in rats.

METHODS: An intestinal I/R model was developed by superior mesenteric artery (SMA) occlusion. Fifty SD rats were randomly divided into five groups: a sham group, an intestinal I/R 1 h (I/R₁) group, an intestinal I/R 4 h (I/R₄) group, an I/R + BTR 1 h (BTR₁) group, and an I/R + BTR 4 h (BTR₄) group. After induction of intestinal I/R, BTR (400 mg/kg) or normal saline was subcutaneously injected respectively. At 1 h and 4 h after I/R, intestinal mucosal blood flow (IMBF) was measured by Doppler ultrasound, and blood samples were taken for measurement of tumor necrosis factor-α (TNF-α) and diamine oxidase (DAO) activity. The samples of intestinal tissues were harvested for measurement of microvascular permeability, tissue water content, and levels of myeloperoxidase (MPO), malondialdehyde (MDA) and vascular endothelial growth factor (VEGF). The pathological changes of intestinal tissues were also observed.

RESULTS: Plasma levels of TNF-α and DAO, tissue water content, microvascular permeability, and the intestinal levels of VEGF, MPO, and MDA were significantly elevated and IMBF reduced in the I/R₁ and I/R₄ groups compared with the sham group. The levels of above parameters were significantly reversed in the BTR₁ and BTR₄ groups compared with the I/R₁ and I/R₄ groups after I/R injury.

CONCLUSION: Sodium butyrate inhabits increased inflammatory mediators and high microvascular permeability and protects against I/R induced gut injury in rats.

Protective effects of fenofibrate against acute lung injury induced by intestinal ischemia/reperfusion in mice

This experiment was conducted to evaluate whether pretreatment with fenofibrate could mitigate acute lung injury (ALI) in a mice model of intestinal ischemia/reperfusion (I/R). Male C57BL/6 mice were randomly assigned into three groups (n = 6): sham, intestinal I/R + vehicle, and intestinal I/R + fenofibrate. Intestinal I/R was achieved by clamping the superior mesenteric artery. Fenofibrate (100 mg/kg) or equal volume of vehicle was injected intraperitoneally 60 minutes before the ischemia. At the end of experiment, measurement of pathohistological score, inflammatory mediators and other markers were performed. In addition, a 24-hour survival experiment was conducted in intestinal I/R mice treated with fenofibrate or vehicle. The chief results were as anticipated. Pathohistological evaluation indicated that fenofibrate ameliorated the local intestine damage and distant lung injury. Pretreatment with fenofibrate significantly decreased inflammatory factors in both the intestine and the lung. Consistently, renal creatine levels and hepatic ALT levels were significantly decreased in the fenofibrate group. Moreover, serum systemic inflammatory response indicators were significantly alleviated in the fenofibrate group. In addition, fenofibrate administration significantly improved the survival rate. Collectively, our data indicated that pretreatment with fenofibrate prior to ischemia attenuated intestinal I/R injury and ALI.

The Cardioprotective Effect of Icariin on Ischemia-Reperfusion Injury in Isolated Rat Heart: Potential Involvement of the PI3K-Akt Signaling Pathway

AIMS

Icariin (ICA), a flavonoid isolated from epimedii, has been reported to have potential protective effects on the cardiovascular system. This study is to investigate the effect and the underlying mechanisms of ICA on ischemia/reperfusion (I/R) injury.

METHODS

Wister rat hearts were subjected to I/R using Langendorff perfusion system. Cardiac function, myocardial infarct size, lactate dehydrogenase (LDH), and creatine kinase-MB (CK-MB) activities in coronary effluent, and superoxide dismutase (SOD) and malondialdehyde (MDA) content in heart tissue and cardiomyocyte apoptosis were assayed.

RESULTS

Compared with the I/R group, ICA treatment significantly improved cardiac function, decreased myocardial infarct size, enzyme activity, oxidative stress, and apoptosis. In addition, ICA treatment lead to an increased p-Akt level, which was partially reversed by LY294002, a PI3K pathway inhibitor.

CONCLUSION

Our study suggests that ICA has a cardioprotective effect against I/R injury, which is associated with its antioxidative and anti-apoptotic effect, at least partially, through the activation of PI3K-Akt signaling pathway.

Alpha7 nicotinic acetylcholine receptor activation attenuated intestine-derived acute lung injury

BACKGROUND

Intestinal ischemia-reperfusion (IIR) could lead to acute lung injury, associated with severe alveolar epithelial cells inflammatory and oxidative injury. Alpha7 nicotinic acetylcholine receptor (α7nAChR) is an essential component of the cholinergic anti-inflammatory pathway. The aim of this study was to investigate the important role of α7nAChR on the lung subjected to IIR.

METHODS

Thirty-two Sprague-Dawley rats were randomly divided into four groups (n = 8 in each): sham group (group S), model group (group M), α7nAChR agonist PNU-282987-treated group (group PNU), and specific α7nAChR antagonist methyllycaconitine-treated group (group MLA). Intestinal IR damage was induced by clamping the superior mesenteric artery for 75 min, followed by a 120-min reperfusion. All rats were killed at 2 h after release of the clamps. The histologic examination of lungs was made, and lung water content was detected. Expression levels of malondialdehyde, tumor necrosis factor alpha, interleukin-6, and superoxide dismutase activity of the lungs were detected. Additionally, expression level of toll-like receptor (TLR)4 and nuclear factor-kappaB (NF-κB p65) in the nucleus of lung tissue and apoptosis-related protein (Bax, Bcl-2, and cleaved-caspase3) were detected using Western blot.

RESULTS

Lungs were damaged after intestine IR, manifested by higher lung water content, histologic score, concentrations of interleukin-6, tumor necrosis factor alpha, and malondialdehyde of group M than those of group S, accompanied with decreased superoxide dismutase activity (P < 0.05). PNU treatment could significantly improve the pulmonary function of rats subjected to IIR. These effects of activation of α7nAChR were associated with suppression of TLR4/NF-κB pathway and subsequent reduction of apoptosis-related protein. However, MLA treatment aggravated lung injury.

CONCLUSIONS

α7nAChR plays a role in acute lung injury induced by IIR via attenuating lung oxidative stress and inflammation through suppression of TLR4/NF-κB pathway, resulting in reduction of apoptosis in the lung.

Treatment with either obestatin or ghrelin attenuates mesenteric ischemia-reperfusion-induced oxidative injury of the ileum and the remote organ lung

To evaluate the effects of exogenous ghrelin or obestatin on intestinal injury and accompanying pulmonary injury, intestinal ischemia-reperfusion (I/R) was induced in rats by obstructing the superior mesenteric artery for 60min, whereas laparotomy was performed in the sham group. At the beginning of the 90-min reperfusion period, the rats were injected with obestatin (100μg/kg), ghrelin (10ng/kg), or saline intravenously (iv). At the end of reperfusion, the blood, ileum, and lung samples were taken for the histological and biochemical assays. In the saline-treated I/R group, the increased serum interleukin (IL)-1β level, high damage scores, and elevated tissue malondialdehyde level and collagen content in both tissues were significantly reduced by obestatin or ghrelin. Increased ileal myeloperoxidase activity of the saline-treated I/R group was reduced by treatment with obestatin or ghrelin, whereas increased pulmonary myeloperoxidase activity was reduced with administration of obestatin. Increased DNA fragmentation in the ileum of the saline-treated I/R group was reduced by both peptides. Elevated luminol-lucigenin chemiluminescence levels and nuclear factor kappa B (NF-κB) messenger RNA (mRNA) expression in the ileum of the saline-treated-I/R group were significantly decreased by obestatin or ghrelin treatment. I/R-induced depletion of the antioxidant glutathione in both ileal and pulmonary tissues was prevented with either obestatin or ghrelin treatment. Administration of either obestatin or ghrelin exerts similar protective effects against I/R-induced ileal and pulmonary injury, thus warranting further investigation for their possible use against ischemic intestinal injury.