DHA attenuates hepatic ischemia reperfusion injury by inhibiting pyroptosis and activating PI3K/Akt pathway

Network pharmacology, molecular docking, and experimental verification reveal the mechanism of Yi-Shen-Hua-Shi granules treating acute kidney injury

ETHNOPHARMACOLOGICAL RELEVANCE

Yi-Shen-Hua-Shi granules (YSHSG) have been shown to improve kidney function in various renal disorders, which are characterized by the sudden decline and impairment of kidney function.

AIM OF THE STUDY

To investigate the precise mechanisms and targets of YSHSG in combating sepsis-induced AKI.

MATERIALS AND METHODS

Through network pharmacology, the active ingredients, main target proteins, and related signaling pathways of YSHSG in the treatment of sepsis-induced AKI were predicted. The AKI model was induced by sepsis using the cecal ligation and puncture (CLP) technique. Prior to the operation, YSHSG was administered intragastrically once daily for 1 week. Blood and kidney tissues were collected 48 h post-CLP to verify the network pharmacology analysis.

RESULTS

The core target proteins of YSHSG in the treatment of sepsis-induced AKI include AKT1, JUN, IL6, PTGS2, NFKBIA, MAPK3, Caspase-3 and MMP9, which were further confirmed by molecular docking. Pathway analyses such as Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) show that YSHSG plays a role in protecting the kidneys from sepsis-induced AKI through the PI3K/AKT, TNF, and IL17 signaling pathways. These findings were validated using qPCR and western blotting. In vivo experiments demonstrated that YSHSG inhibits the activation of TNF and IL17 signaling pathways while protecting against deactivation of the PI3K/AKT signaling pathway in sepsis-induced AKI. YSHSG also exhibits an effect on attenuating inflammation response and pyroptosis processes associated with the PI3K/AKT, TNF, and IL17 signaling pathways.

CONCLUSION

YSHSG mitigated sepsis-induced AKI by influencing the PI3K/AKT, TNF, and IL17 signaling pathways associated with inflammation and pyroptosis.

Pyroptosis; igniting neuropsychiatric disorders from mild depression to aging-related neurodegeneration

Neuropsychiatric disorders significantly impact global health and socioeconomic well-being, highlighting the urgent need for effective treatments. Chronic inflammation, often driven by the innate immune system, is a key feature of many neuropsychiatric conditions. NOD-like receptors (NLRs), which are intracellular sensors, detect danger signals and trigger inflammation. Among these, NLR protein (NLRP) inflammasomes play a crucial role by releasing pro-inflammatory cytokines and inducing a particular cell death process known as pyroptosis. Pyroptosis is defined as a proinflammatory form of programmed cell death executed by cysteine-aspartic proteases, also known as caspases. Currently, the role of pyroptotic flux has emerged as a critical factor in innate immunity and the pathogenesis of multiple diseases. Emerging evidence suggests that the induction of pyroptosis, primarily due to NLRP inflammasome activation, is involved in the pathophysiology of various neuropsychiatric disorders, including depression, stress-related issues, schizophrenia, autism spectrum disorders, and neurodegenerative diseases. Within this framework, the current review explores the complex relationship between pyroptosis and neuropsychiatric diseases, aiming to identify potential therapeutic targets for these challenging conditions.

Pyroptosis: A Novel Therapeutic Target for Bioactive Compounds in Human Disease Treatment? A Narrative Review

Background/Objectives: Bioactive compounds possess the ability to maintain health and improve diseases by regulating inflammation and cell death processes. Pyroptosis is programmed cell death related to inflammation and exerts a critical role in the development and progression of different types of diseases. This narrative review aims to investigate and discuss the effects of dietary bioactive compounds on pyroptosis in different common human pathologies, such as inflammatory disease, bacterial infection, injury disease, cancer, diabetes and heart disease, etc. Method: Studies published in the major databases until December 2024 in English were considered, for a total of 50 papers. Results: The current evidence demonstrated that the bioactive compounds are able to regulate the pyroptosis process by modulating different inflammasome sensors (NLRP1, NLRP3, and AIM2), caspase family proteins (caspase-1, caspase-3, and caspase-11), and gasdermins (GSDMD and GSDME) in many pathological conditions related to inflammation, including cancer and cardiovascular diseases. Conclusions: Bioactive compounds have powerful potential to be the candidate drug for pyroptosis modulation in inflammatory diseases, even if more clinical studies are needed to confirm the effects and establish efficient doses for humans.

ω-3PUFAs Inhibit Hypoxia-Induced Retinal Neovascularization via Regulating Microglial Pyroptosis through METTL14-Mediated m6A Modification of IFNB1 mRNA

Retinal neovascular disease is the leading reason of vision impairment in all ages. Here, we figured out the function and mechanism of omega-3 polyunsaturated fatty acids (ω-3PUFAs) in hypoxia-induced retinal neovascularization by focusing on microglial pyroptosis. Microglia BV-2 cells were given ω-3PUFAs treatment and co-cultured with mouse retinal microvascular endothelial cells (MRMECs) under hypoxia. Tube formation assay, transwell assay and wound healing assay were utilized to monitor the MRMEC angiogenesis. Cell counting kit-8, western blot, lactate dehydrogenase assay, and enzyme-linked immunosorbent assay were used to assess pyroptosis of BV-2 cells. RNA sequencing and methylated RNA immunoprecipitation-polymerase chain reaction were utilized to identify the target gene of methyltransferase-like 14 (METTL14) and its N6-methyladenosine (m6A) level in BV-2 cells. BV-2 cells prominently enhanced MRMEC angiogenesis under hypoxia, but this effect was abolished after ω-3PUFAs treatment. ω-3PUFAs inhibited pyroptosis in hypoxia-induced BV-2 cells, and BV-2 cell pyroptosis boosted angiogenesis of MRMECs. Additionally, ω-3PUFAs markedly augment the expression of MELLL14 in BV-2 cells, and METTL14 knockdown promoted BV-2 cell pyroptosis and BV-2 cell-mediated angiogenesis in MEMECs. Mechanistically, interferon beta 1 (IFNB1) was a target of METTL14, and METTL14 silencing increased the mRNA expression and decreased the m6A modification of IFNB1 in BV-2 cells. Our results uncovered that ω-3PUFAs diminished hypoxia-induced retinal neovascularization through controlling microglial pyroptosis via METTL14-mediated m6A modification. This study offers a novel potential target for the treatment of retinal neovascular diseases.

Programmed cell death, from liver Ischemia-Reperfusion injury perspective: An overview

Liver ischemia-reperfusion injury (LIRI) commonly occurs in liver resection, liver transplantation, shock, and other hemorrhagic conditions, resulting in profound local and systemic effects via associated inflammatory responses and hepatic cell death. Hepatocyte death is a significant component of LIRI and its mechanism was previously thought to be limited to apoptosis and necrosis. With the discovery of novel types of programmed cell death (PCD), necroptosis, ferroptosis, pyroptosis, autophagy, NETosis, and parthanatos have been shown to be involved in LIRI. Understanding the mechanisms underlying cell death following LIRI is indispensable to mitigating the widespread effects of LIRI. Here, we review the roles of different PCD and discuss potential therapy in LIRI.

Targeting NF-κB in Hepatic Ischemia-Reperfusion Alleviation: from Signaling Networks to Therapeutic Targeting

Hepatic ischemia-reperfusion injury (HIRI) is a major complication of liver trauma, resection, and transplantation that can lead to liver dysfunction and failure. Scholars have proposed a variety of liver protection methods aimed at reducing ischemia-reperfusion damage, but there is still a lack of effective treatment methods, which urgently needs to find new effective treatment methods for patients. Many studies have reported that signaling pathway plays a key role in HIRI pathological process and liver function recovery mechanism, among which nuclear transfer factor-κB (NF-κB) signaling pathway is one of the signal transduction closely related to disease. NF-κB pathway is closely related to HIRI pathologic process, and inhibition of this pathway can delay oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction. In addition, NF-κB can also interact with PI3K/Akt, MAPK, and Nrf2 signaling pathways to participate in HIRI regulation. Based on the role of NF-κB pathway in HIRI, it may be a potential target pathway for HIRI. This review emphasizes the role of inhibiting the NF-κB signaling pathway in oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction in HIRI, as well as the effects of related drugs or inhibitors targeting NF-κB on HIRI. The objective of this review is to elucidate the role and mechanism of NF-κB pathway in HIRI, emphasize the important role of NF-κB pathway in the prevention and treatment of HIRI, and provide a theoretical basis for the target NF-κB pathway as a therapy for HIRI.

Exploring the Mechanism of Si-miao-yong-an Decoction in the Treatment of Coronary Heart Disease based on Network Pharmacology and Experimental Verification

BACKGROUND

To investigate the active ingredients and the mechanisms of Si-miaoyong- an Decoction (SMYA) in the treatment of coronary heart disease (CHD) by using network pharmacology, molecular docking technology, and in vitro validation.

METHODS

Through the Chinese Medicine System Pharmacology Database and Analysis Platform (TCMSP), Uniprot database, GeneCards database, and DAVID database, we explored the core compounds, core targets and signal pathways of the effective compounds of SMYA in the treatment of CHD. Molecular docking technology was applied to evaluate the interactions between active compounds and key targets. The hypoxia-reoxygenation H9C2 cell model was applied to carry out in vitro verification experiments. A total of 109 active ingredients and 242 potential targets were screened from SMYA. A total of 1491 CHD-related targets were retrieved through the Gene- Cards database and 155 overlapping CHD-related SMYA targets were obtained. PPI network topology analysis indicated that the core targets of SMYA in the treatment of CHD include interleukin- 6 (IL-6), tumor suppressor gene (TP53), tumor necrosis factor (TNF), vascular endothelial growth factor A (VEGFA), phosphorylated protein kinase (AKT1) and mitogen-activated protein kinase (MAPK). KEGG enrichment analysis demonstrated that SMYA could regulate Pathways in cancer, phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) signaling pathway, hypoxiainducible factor-1(HIF-1) signaling pathway, VEGF signaling pathway, etc. Results: Molecular docking showed that quercetin had a significant binding activity with VEGFA and AKT1. In vitro studies verified that quercetin, the major effective component of SMYA, has a protective effect on the cell injury model of cardiomyocytes, partially by up-regulating expressions of phosphorylated AKT1 and VEGFA.

CONCLUSION

SMYA has multiple components and treats CHD by acting on multiple targets. Quercetin is one of its key ingredients and may protect against CHD by regulating AKT/VEGFA pathway.

Ghrelin protects against ischemia/reperfusion-induced hepatic injury via inhibiting Caspase-11-mediated noncanonical pyroptosis

BACKGROUND

Ischemia/reperfusion (I/R) injury is a complication of liver transplantation. I/R-induced inflammatory cell death, namely, pyroptosis, that is triggered by overactive inflammasomes results in the production of proinflammatory cytokines. Hepatic I/R injury correlates with the activation of the Caspase-11-mediated pyroptosis pathway. We investigated whether ghrelin, which is a pleiotropic gut hormone, may have anti-hepatic I/R injury effects, but the mechanism by which Ghrelin ameliorates hepatic I/R -induced injury remains a mystery.

METHODS

Hepatic I/R injury was induced in a mouse model by clamping the left and right lobes of the liver for 90 min followed by reperfusion for 6 h, 12 h, or 24 h. As treatment, a saline with or without ghrelin was infused via the tail vain. Hepatocytes were isolated using a two-step collagenase liver perfusion method.

RESULTS

In our study, treatment with ghrelin protected against hepatic I/R injury as shown by decreased alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels (p < 0.001) and reduced the histological injury in liver tissues compared with untreated controls. The LDH level of primary hepatocytes was increased by hypoxia/reoxygenation (H/R), and it was then restored to normal levels by ghrelin-treatment (p < 0.05). Western blotting analysis showed that ghrelin significantly inhibited the expression of pyroptosis-related proteins, including Caspase-11, GSDMD-N, NLRP3 and HMGB1, both in vivo and in vitro (all p < 0.05) compared with the untreated controls. Immunofluorescence showed that the expression of Gasdamin D (GSDMD) in hepatocytes was increased after I/R or H/R, whereas GSDMD expression was reduced by ghrelin treatment (p < 0.05).

CONCLUSIONS

Our findings suggest that ghrelin ameliorated I/R-induced hepatic injury by inhibiting Caspase-11-mediated pyroptosis. Ghrelin may be a potential therapeutic option to prevent hepatic I/R injury after liver transplantation.

Anticancer mechanisms on pyroptosis induced by Oridonin: New potential targeted therapeutic strategies

Pyroptosis is a type of inflammatory cell death that is triggered by the formation of pores on the cell membrane by gasdermin (GSDM) family proteins. This process activates inflammasomes and leads to the maturation and release of proinflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18). Pyroptosis, a form of programmed cell death, has been found to be associated with various biomolecules such as caspases, granzymes, non-coding RNA (lncRNA), reactive oxygen species (ROS), and NOD-like receptor protein 3 (NLRP3). These biomolecules have been shown to play a dual role in cancer by affecting cell proliferation, metastasis, and the tumor microenvironment (TME), resulting in both tumor promotion and anti-tumor effects. Recent studies have found that Oridonin (Ori) has anti-tumor effects by regulating pyroptosis through various pathways. Ori can inhibit pyroptosis by inhibiting caspase-1, which is responsible for activating pyroptosis of the canonical pathway. Additionally, Ori can inhibit pyroptosis by inhibiting NLRP3, which is responsible for activating pyroptosis of the noncanonical pathway. Interestingly, Ori can also activate pyroptosis by activating caspase-3 and caspase-8, which are responsible for activating pyroptosis of the emerging pathway; Ori has been found to be effective in inhibiting pyroptosis by blocking the action of perforin, which is responsible for facilitating the entry of granzyme into cells and activating pyroptosis. Additionally, Ori plays a crucial role in regulating pyroptosis by promoting the accumulation of ROS while inhibiting the ncRNA and NLRP3 pathways. It is worth noting that all of these pathways ultimately regulate pyroptosis by influencing the cleavage of GSDM, which is a key factor in the process. These studies concludes that Ori has extensive anti-cancer effects that are related to its potential regulatory function on pyroptosis. The paper summarizes several potential ways in which Ori participates in the regulation of pyroptosis, providing a reference for further study on the relationship between Ori, pyroptosis, and cancer.

Sterile inflammation in liver transplantation

Sterile inflammation is the immune response to damage-associated molecular patterns (DAMPs) released during cell death in the absence of foreign pathogens. In the setting of solid organ transplantation, ischemia-reperfusion injury results in mitochondria-mediated production of reactive oxygen and nitrogen species that are a major cause of uncontrolled cell death and release of various DAMPs from the graft tissue. When properly regulated, the immune response initiated by DAMP-sensing serves as means of damage control and is necessary for initiation of recovery pathways and re-establishment of homeostasis. In contrast, a dysregulated or overt sterile inflammatory response can inadvertently lead to further injury through recruitment of immune cells, innate immune cell activation, and sensitization of the adaptive immune system. In liver transplantation, sterile inflammation may manifest as early graft dysfunction, acute graft failure, or increased risk of immunosuppression-resistant rejection. Understanding the mechanisms of the development of sterile inflammation in the setting of liver transplantation is crucial for finding reliable biomarkers that predict graft function, and for development of therapeutic approaches to improve long-term transplant outcomes. Here, we discuss the recent advances that have been made to elucidate the early signs of sterile inflammation and extent of damage from it. We also discuss new therapeutics that may be effective in quelling the detrimental effects of sterile inflammation.

Hydrogen sulfide ameliorates abdominal aorta coarctation-induced myocardial fibrosis by inhibiting pyroptosis through regulating eukaryotic translation initiation factor 2α phosphorylation and activating PI3K/AKT1 pathway

This study aimed to assess the effects of exogenous hydrogen sulfide (H2S) on abdominal aorta coarctation (AAC) induced myocardial fibrosis (MF) and autophagy in rats. Forty-four Sprague-Dawley rats were randomly divided into control group, AAC group, AAC + H2S group, and H2S control group. After a model of rats with AAC was built surgically, AAC + H2S group and H2S group were injected intraperitoneally with H2S (100 μmol/kg) daily. The rats in the control group and the AAC group were injected with the same amount of PBS. We observed that H2S can improve left ventricular function and the deposition of myocardial collagen fibers, inhibit pyroptosis, down-regulate the expression of P-eif2α in myocardial tissue, and inhibit cell autophagy by activating the phosphatidylinositol 3-kinase (PI3K)/AKT1 signaling pathway (p < 0.05). In addition, angiotensin II (1 μM) H9c2 cardiomyocytes were injured in vitro experiments, and it was also observed that pyroptosis was inhibited after H2S (400 μmol/kg) intervention, the expression of P-eif2α in cardiomyocytes was significantly down-regulated, and the PI3K/AKT1 signaling pathway was activated at the same time. Therefore, increasing the expression of P-eif2α reverses the activation of the PI3K/AKT1 signaling pathway by H2S. In conclusion, these findings suggest that exogenous H2S can ameliorate MF in rats with AAC by inhibiting pyroptosis, and the mechanism may be associated with inhibiting the phosphorylation of eif2α and activating the PI3K/AKT1 signaling pathway to inhibit excessive cell autophagy.

Role of Pyroptosis, a Pro-inflammatory Programmed Cell Death, in Epilepsy

Epilepsy is one of the most common serious brain diseases worldwide. Programmed cell death (PCD), a cellular self-destruction phenomenon, has been greatly documented in neurodegenerative diseases. Pyroptosis is a well-known pro-inflammatory PCD, and its involvement in epilepsy has been reported in animal models of epilepsy and also epileptic patients. Canonical (caspase-1-dependent) and non-canonical (caspase-1-independent) pathways are two main mechanisms implicated in pyroptotic cell death. Mouse caspase-11 or human analogues caspase-4/5 induce the non-canonical pathway. In both pathways, membrane gasdermin (GSDMD) pores contribute to pro-inflammatory cytokine release and lead to membrane destabilization and cell lysis. IL-1β and IL-18 are pro-inflammatory cytokines that are released following pyroptotic PCD. Brain inflammation increases excitability in the nervous system, promotes seizure activity, and is probably associated with the molecular and synaptic changes involved in epileptogenesis. Pro-inflammatory cytokines affect the glutamate and GABA neurotransmitter release as well as their receptors, thereby resulting in seizure activity. This review is intended to provide an overview of the current published works on pyroptotic cell death in epilepsy. The mechanisms by which pro-inflammatory cytokines, including IL-1β and IL-18 can promote epileptic discharges were also collected. According to this survey, since the involvement of pyroptosis in the development of epilepsy has been established, pyroptosis-targeted therapies may represent a novel anti-epileptogenic strategy.

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.

Co-exposure to molybdenum and cadmium triggers pyroptosis and autophagy by PI3K/AKT axis in duck spleens

Excessive amounts of molybdenum (Mo) and cadmium (Cd) are toxicant, but their combined immunotoxicity are not clearly understood. To estimate united impacts of Mo and Cd on pyroptosis and autophagy by PI3K/AKT axis in duck spleens, Mo or/and Cd subchronic toxicity models of ducks were established by feeding diets with different dosages of Mo or/and Cd. Data show that Mo or/and Cd cause oxidative stress by increasing MDA concentration, and decreasing T-AOC, CAT, GSH-Px and T-SOD activities, restrain PI3K/AKT axis by decreasing PI3K, AKT, p-AKT expression levels, which evokes pyroptosis and autophagy by elevating IL-1β, IL-18 concentrations and NLRP3, Caspase-1, ASC, GSDME, GSDMA, NEK7, IL-1β, IL-18 expression levels, promoting autophagosomes, LC3 puncta, Atg5, LC3A, LC3B, LC3II/LC3I and Beclin-1 expression levels, and reducing expression levels of P62 and Dynein. Furthermore, the variations of abovementioned indexes are most pronounced in co-treated group. Overall, results reveal that Mo or/and Cd may evoke pyroptosis and autophagy by PI3K/AKT axis in duck spleens. The association of Mo and Cd exacerbates the changes.

Vitamin C alleviates LPS-induced myocardial injury by inhibiting pyroptosis via the ROS-AKT/mTOR signalling pathway

BACKGROUND

The efficacy of vitamin C in sepsis remains controversial. Whether vitamin C can alleviate lipopolysaccharide (LPS)-induced myocardial injury by inhibiting pyroptosis has not been studied. This study aimed to evaluate the effects of vitamin C on LPS-induced myocardial injury in vitro.

METHODS

H9C2 cells were treated with indicated concentrations of LPS, and the cell viability was then assessed by CCK-8 assay. The levels of lactate dehydrogenase (LDH), CK-MB, IL-18 and IL-1β were examined by enzyme-linked immunosorbent assay (ELISA). The levels of intracellular reactive oxygen species (ROS) were measured using the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA). Western blot assays were conducted to determine the levels of the ROS-associated protein nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) and pyroptosis-associated proteins, such as NOD-like receptor (NLR) family pyrin domain containing 3 (NLRP3), caspase-1 and gasdermin D (GSDMD). The AKT inhibitor MK-2206 was then applied to explore the signalling pathway. Finally, H9C2 cells were divided into the control group, LPS group, vitamin C + LPS group, and N-acetyl-L-cysteine (NAC) + LPS group. The intracellular ROS, levels of associated proteins, cell viability, and release of LDH, CK-MB, IL-18 and IL-1β were examined.

RESULTS

LPS decreased cell viability and induced ROS and pyroptosis in H9C2 cells in a dose-dependent manner. Moreover, LPS activated the AKT/mTOR pathway in H9C2 cells. The AKT inhibitor MK-2206 protected H9C2 cells from LPS-induced death by suppressing pyroptosis, without changing intracellular ROS level. Vitamin C significantly inhibited intracellular ROS and cell pyroptosis in LPS-treated H9C2 cells. Moreover, vitamin C suppressed the activation of the AKT/mTOR pathway.

CONCLUSIONS

Our data suggest that vitamin C alleviates LPS-induced myocardial injury by inhibiting pyroptosis via the ROS-AKT/mTOR signalling pathway and thus provide novel insights into the prevention of sepsis-induced myocardial dysfunction.

Emerging Role of NLRP3 Inflammasome and Pyroptosis in Liver Transplantation

The nucleotide-binding domain leucine-rich repeat-receptor, pyrin domain-containing-3 (NLRP3) inflammasome contributes to the inflammatory response by activating caspase-1, which in turn participates in the maturation of interleukin (IL)-1β and IL-18, which are mainly secreted via pyroptosis. Pyroptosis is a lytic type of cell death that is controlled by caspase-1 processing gasdermin D. The amino-terminal fragment of gasdermin D inserts into the plasma membrane, creating stable pores and enabling the release of several proinflammatory factors. The activation of NLRP3 inflammasome and pyroptosis has been involved in the progression of liver fibrosis and its end-stage cirrhosis, which is among the main etiologies for liver transplantation (LT). Moreover, the NLRP3 inflammasome is involved in ischemia-reperfusion injury and early inflammation and rejection after LT. In this review, we summarize the recent literature addressing the role of the NLRP3 inflammasome and pyroptosis in all stages involved in LT and argue the potential targeting of this pathway as a future therapeutic strategy to improve LT outcomes. Likewise, we also discuss the impact of graft quality influenced by donation after circulatory death and the expected role of machine perfusion technology to modify the injury response related to inflammasome activation.

Pyroptosis: A Newly Discovered Therapeutic Target for Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury, uncommon among patients suffering from myocardial infarction, stroke, or acute kidney injury, can result in cell death and organ dysfunction. Previous studies have shown that different types of cell death, including apoptosis, necrosis, and autophagy, can occur during I/R injury. Pyroptosis, which is characterized by cell membrane pore formation, pro-inflammatory cytokine release, and cell burst, and which differentiates itself from apoptosis and necroptosis, has been found to be closely related to I/R injury. Therefore, targeting the signaling pathways and key regulators of pyroptosis may be favorable for the treatment of I/R injury, which is far from adequate at present. This review summarizes the current status of pyroptosis and its connection to I/R in different organs, as well as potential treatment strategies targeting it to combat I/R injury.

Ferroptosis of Endothelial Cells in Vascular Diseases

Endothelial cells (ECs) line the inner surface of blood vessels and play a substantial role in vascular biology. Endothelial dysfunction (ED) is strongly correlated with the initiation and progression of many vascular diseases. Regulated cell death, such as ferroptosis, is one of the multiple mechanisms that lead to ED. Ferroptosis is an iron-dependent programmed cell death associated with various vascular diseases, such as cardiovascular, cerebrovascular, and pulmonary vascular diseases. This review summarized ferroptosis of ECs in vascular diseases and discussed potential therapeutic strategies for treating ferroptosis of ECs. In addition to lipid peroxidation inhibitors and iron chelators, a growing body of evidence showed that clinical drugs, natural products, and intervention of noncoding RNAs may also inhibit ferroptosis of ECs.

NLRP3-mediated pyroptosis in diabetic nephropathy

Diabetic nephropathy (DN) is the main cause of end-stage renal disease (ESRD), which is characterized by a series of abnormal changes such as glomerulosclerosis, podocyte loss, renal tubular atrophy and excessive deposition of extracellular matrix. Simultaneously, the occurrence of inflammatory reaction can promote the aggravation of DN-induced kidney injury. The most important processes in the canonical inflammasome pathway are inflammasome activation and membrane pore formation mediated by gasdermin family. Converging studies shows that pyroptosis can occur in renal intrinsic cells and participate in the development of DN, and its activation mechanism involves a variety of signaling pathways. Meanwhile, the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome can not only lead to the occurrence of inflammatory response, but also induce pyroptosis. In addition, a number of drugs targeting pyroptosis-associated proteins have been shown to have potential for treating DN. Consequently, the pathogenesis of pyroptosis and several possible activation pathways of NLRP3 inflammasome were reviewed, and the potential drugs used to treat pyroptosis in DN were summarized in this review. Although relevant studies are still not thorough and comprehensive, these findings still have certain reference value for the understanding, treatment and prognosis of DN.

Constructing and Validating a Pyroptosis-Related Genes Prognostic Signature for Stomach Adenocarcinoma and Immune Infiltration: Potential Biomarkers for Predicting the Overall Survival

Background

Stomach adenocarcinoma (STAD) is a kind of cancer that begins in the stomach cells and has a poor overall survival rate. Following resection surgery, chemotherapy has been suggested as a curative method for stomach cancer. However, it is ineffective. Pyroptosis, a kind of inflammatory programmed cell death, has been shown to play a significant role in the development and progression of STAD. However, whether pyroptosis-related genes (PRGs) can be utilized to predict the diagnosis and prognosis of gastric cancer remains unknown.

Method

The research measured at predictive PRGs in STAD samples from TCGA and GEO. Lasso regression was used to build the prediction model. Coexpression analysis revealed that gene expression was linked to pyroptosis. PRGs were found to be overexpressed in high-risk individuals, implying that they could be used in a model to predict STAD prognosis.

Result

Immunological and tumor-related pathways were discovered using GSEA. In STAD patients, the genes GPX3, PDGFRL, RGS2, and SERPINE1 may be connected to the cancer process. The levels of expression also differed between the two risk groups.

Conclusion

The purpose of this study is to identify and verify STAD-associated PRGs that can effectively guide prognosis and the immunological milieu in STAD patients as well as offer evidence for the development of pyroptosis-related molecularly targeted therapeutics. Therefore, PRGs and the link between immunological and PRGs in STAD may be therapeutic targets.

KDM3A Attenuates Myocardial Ischemic and Reperfusion Injury by Ameliorating Cardiac Microvascular Endothelial Cell Pyroptosis

Cardiac microvascular endothelial cell ischemia-reperfusion (CMEC I/R) injury occurs in approximately 50% of acute myocardial infarction patients subjected to successful revascularization therapy. This injury leads to cardiac microcirculatory system dysfunctions, which seriously affect cardiac functions and long-term prognostic outcomes. Previously, we elucidated the role of lysine-specific demethylase 3A (KDM3A) in protecting cardiomyocytes from I/R injury; however, its roles in CMEC I/R injuries have yet to be fully established. In this study, hypoxia/reoxygenation (H/R) treatment significantly impaired CMEC functions and induced their pyroptosis, accompanied by KDM3A downregulation. Then, gain- and loss-of-function assays were performed to investigate the roles of KDM3A in CMEC H/R injury in vitro. KDM3A knockout enhanced CMEC malfunctions and accelerated the expressions of pyroptosis-associated proteins, such as NLRP3, cleaved-caspase-1, ASC, IL-1β, GSDMD-N, and IL-18. Conversely, KDM3A overexpression developed ameliorated alternations in CMEC H/R injury. In vivo, KDM3A knockout resulted in the deterioration of cardiac functions and decreased the no-reflow area as well as capillary density. Mechanistically, KDM3A activated the PI3K/Akt signaling pathway and ameliorated I/R-mediated CMEC pyroptosis. In conclusion, KDM3A is a promising treatment target for alleviating CMEC I/R injury.

Small molecules as modulators of regulated cell death against ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury contributes to disability and mortality worldwide. Due to the complicated mechanisms and lack of proper therapeutic targets, few interventions are available that specifically target the pathogenesis of IR injury. Regulated cell death (RCD) of endothelial and parenchymal cells is recognized as the promising intervening target. Recent advances in IR injury suggest that small molecules exhibit beneficial effects on various RCD against IR injury, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis, and parthanatos. Here, we describe the mechanisms behind these novel promising therapeutic targets and explain the machinery powering the small molecules. These small molecules exert protection by targeting endothelial or parenchymal cells to alleviate IR injury. Therapies of the ideal combination of small molecules targeting multiple cell types have shown potent synergetic therapeutic effects, laying the foundation for novel strategies to attenuate IR injury.

Dexmedetomidine Inhibits Gasdermin D-Induced Pyroptosis via the PI3K/AKT/GSK3β Pathway to Attenuate Neuroinflammation in Early Brain Injury After Subarachnoid Hemorrhage in Rats

Subarachnoid hemorrhage (SAH) is one kind of life-threatening stroke, which leads to severe brain damage. Pyroptosis plays a critical role in early brain injury (EBI) after SAH. Previous reports suggest that SAH-induced brain edema, cell apoptosis, and neuronal injury could be suppressed by dexmedetomidine (Dex). In this study, we used a rat model of SAH to investigate the effect of Dex on pyroptosis in EBI after SAH and to determine the mechanisms involved. Pyroptosis was found in microglia in EBI after SAH. Dex significantly alleviated microglia pyroptosis via reducing pyroptosis executioner GSDMD and inhibited the release of proinflammatory cytokines induced by SAH. Furthermore, the reduction of GSDMD by Dex was abolished by the PI3K inhibitor LY294002. In conclusion, our data demonstrated that Dex reduces microglia pyroptosis in EBI after SAH via the activation of the PI3K/AKT/GSK3β pathway.

Inhibition of AKT induces p53/SIRT6/PARP1-dependent parthanatos to suppress tumor growth

BACKGROUND

Targeting AKT suppresses tumor growth through inducing apoptosis, however, during which whether other forms of cell death occurring is poorly understood.

METHODS

The effects of increasing PARP1 dependent cell death (parthanatos) induced by inhibiting AKT on cell proliferation were determined by CCK-8 assay, colony formation assay, Hoechst 33,258 staining and analysis of apoptotic cells by flow cytometry. For the detailed mechanisms during this process, Western blot analysis, qRT-PCR analysis, immunofluorescence and co-immunoprecipitation were performed. Moreover, the inhibition of tumor growth by inducing p53/SIRT6/PARP1-dependent parthanatos was further verified in the xenograft mouse model.

RESULTS

For the first time, we identified that inhibiting AKT triggered parthanatos, a new form of regulated cell death, leading to colon cancer growth suppression. For the mechanism investigation, we found that after pharmacological or genetic AKT inhibition, p53 interacted with SIRT6 and PARP1 directly to activate it, and promoted the formation of PAR polymer. Subsequently, PAR polymer transported to outer membrane of mitochondria and resulted in AIF releasing and translocating to nucleus thus promoting cell death. While, blocking PARP1 activity significantly rescued colon cancer from death. Furthermore, p53 deletion or mutation eliminated PAR polymer formation, AIF translocation, and PARP1 dependent cell death, which was promoted by overexpression of SIRT6. Meanwhile, reactive oxygen species production was elevated after inhibition of AKT, which might also play a role in the occurrence of parthanatos. In addition, inhibiting AKT initiated protective autophagy simultaneously, which advanced tumor survival and growth.

CONCLUSION

Our findings demonstrated that AKT inhibition induced p53-SIRT6-PARP1 complex formation and the activation of parthanatos, which can be recognized as a novel potential therapeutic strategy for cancer. Video Abstract.

Cadmium and molybdenum co-induce pyroptosis and apoptosis by PTEN/PI3K/AKT axis in the liver of ducks

Cadmium (Cd) and excessive molybdenum (Mo) have adverse impacts on animals. However, the hepatotoxicity co-induced by Cd and Mo in ducks has not been fully elucidated. In order to explore...

Knockdown of TRIM8 Protects HK-2 Cells Against Hypoxia/Reoxygenation-Induced Injury by Inhibiting Oxidative Stress-Mediated Apoptosis and Pyroptosis via PI3K/Akt Signal Pathway

Background

Acute kidney injury (AKI) emerges as an acute and critical disease. Tripartite motif 8 (TRIM8), one number of the TRIM protein family, is proved to participate in ischemia/reperfusion (I/R) injury. However, whether TRIM8 is involved in renal I/R injury and the associated mechanisms are currently unclear.

Purpose

This study aimed to investigate the precise role of TRIM8 and relevant mechanisms in renal I/R injury.

Materials and Methods

In this study, human renal proximal tubular epithelial cells (HK-2 cells) underwent 12 hours of hypoxia and 2 h, 3 h or 4 h of reoxygenation to establish an in vitro hypoxia/reoxygenation (H/R) model. The siRNAs specific to TRIM8 (si-TRIM8) were transfected into HK-2 cells to knockdown TRIM8. The cell H/R model included various groups including Control, H/R, H/R+DMSO, H/R+NAC, si-NC+H/R, si-TRIM8+H/R and si-TRIM8+LY294002+H/R. The cell viability and levels of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂), mRNA, apoptotic proteins, pyroptosis-related proteins and PI3K/AKT pathway-associated proteins were assessed.

Results

In vitro, realtime-quantitative PCR and western-blot analysis showed that the mRNA and protein expression of TRIM8 were obviously upregulated after H/R treatment in HK-2 cells. Compared with the H/R model group, knockdown of TRIM8 significantly increased cell viability and reduced the levels of ROS, H₂O₂, apoptotic proteins (Cleaved caspasebase-3 and BAX) and pyroptosis-related proteins (NLRP3, ASC, Caspase-1, Caspase-11, IL-1β and GSDMD-N). Western-blot analysis also authenticated that PI3K/AKT pathway was activated after TRIM8 inhibition. The application of 5 mM N-acetyl-cysteine, one highly efficient ROS inhibitor, significantly suppressed the expression of apoptotic proteins and pyroptosis-related proteins. Moreover, the combined treatment of TRIM8 knockdown and LY294002 reversed the effects of inhibiting oxidative stress.

Conclusion

Knockdown of TRIM8 can alleviate H/R-induced oxidative stress by triggering the PI3K/AKT pathway, thus attenuating pyropyosis and apoptosis in vitro.

Role of microRNA‑218‑5p in sevoflurane‑induced protective effects in hepatic ischemia/reperfusion injury mice by regulating GAB2/PI3K/AKT pathway

Hepatic ischemia/reperfusion (I/R) injury (HIRI) often occurs following tissue resection, hemorrhagic shock or transplantation surgery. Previous investigations showed that sevoflurane (Sevo), an inhalation anesthetic, had protective properties against different organ damage in animal models including HIRI. This study is aimed to investigate the underlying mechanisms involved in the protective effects of Sevo on HIRI. The present study results showed that treatment with Sevo improved histologic damage, inflammatory response, oxidative stress and apoptosis after hepatic I/R, indicating the protective role of Sevo against liver I/R injury. Importantly, in order to determine the molecular mechanism of Sevo in HIRI, the focus of the study was on microRNA (miR) regulation. By retrieving the microarray data in the Gene Expression Omnibus dataset (GSE72315), miR-218-5p was found to be significantly downregulated by Sevo. Moreover, miR-218-5p overexpression using agomiR-218-5p reversed the protective roles of Sevo against HIRI. Furthermore, GAB2, a positive regulator of PI3K/AKT signaling pathway, was found as a target gene of miR-218-5p. It was also found that the Sevo-mediated protective effects may be dependent on the activation of GAB2/PI3K/AKT. Collectively, these data revealed that Sevo alleviated HIRI in mice by restraining apoptosis, relieving oxidative stress and inflammatory response through the miR-218-5p/GAB2/PI3K/AKT pathway, which helps in understanding the novel mechanism of the hepatic-protection of Sevo.

Dexmedetomidine alleviates hepatic ischaemia-reperfusion injury via the PI3K/AKT/Nrf2-NLRP3 pathway

Hepatic ischaemia-reperfusion (I/R) injury constitutes a tough difficulty in liver surgery. Dexmedetomidine (Dex) plays a protective role in I/R injury. This study investigated protective mechanism of Dex in hepatic I/R injury. The human hepatocyte line L02 received hypoxia/reoxygenation (H/R) treatment to stimulate cell model of hepatic I/R. The levels of pyroptosis proteins and inflammatory factors were detected. Functional rescue experiments were performed to confirm the effects of miR-494 and JUND on hepatic I/R injury. The levels of JUND, PI3K/p-PI3K, AKT/p-AKT, Nrf2, and NLRP3 activation were detected. The rat model of hepatic I/R injury was established to confirm the effect of Dex in vivo. Dex reduced pyroptosis and inflammation in H/R cells. Dex increased miR-494 expression, and miR-494 targeted JUND. miR-494 inhibition or JUND upregulation reversed the protective effect of Dex. Dex repressed NLRP3 inflammasome by activating the PI3K/AKT/Nrf2 pathway. In vivo experiments confirmed the protective effect of Dex on hepatic I/R injury. Overall, Dex repressed NLRP3 inflammasome and alleviated hepatic I/R injury via the miR-494/JUND/PI3K/AKT/Nrf2 axis.

Combating Ischemia-Reperfusion Injury with Micronutrients and Natural Compounds during Solid Organ Transplantation: Data of Clinical Trials and Lessons of Preclinical Findings

Although extended donor criteria grafts bear a higher risk of complications such as graft dysfunction, the exceeding demand requires to extent the pool of potential donors. The risk of complications is highly associated with ischemia-reperfusion injury, a condition characterized by high loads of oxidative stress exceeding antioxidative defense mechanisms. The antioxidative properties, along with other beneficial effects like anti-inflammatory, antiapoptotic or antiarrhythmic effects of several micronutrients and natural compounds, have recently emerged increasing research interest resulting in various preclinical and clinical studies. Preclinical studies reported about ameliorated oxidative stress and inflammatory status, resulting in improved graft survival. Although the majority of clinical studies confirmed these results, reporting about improved recovery and superior organ function, others failed to do so. Yet, only a limited number of micronutrients and natural compounds have been investigated in a (large) clinical trial. Despite some ambiguous clinical results and modest clinical data availability, the vast majority of convincing animal and in vitro data, along with low cost and easy availability, encourage the conductance of future clinical trials. These should implement insights gained from animal data.

Integrative Analysis of the Roles of lncRNAs and mRNAs in Itaconate-Mediated Protection Against Liver Ischemia-Reperfusion Injury in Mice

Purpose

Itaconate is well known for its strong anti-inflammatory and antioxidant effect, but little is known about the potential role of long non-coding RNAs (lncRNAs) in the underlying mechanisms of hepatic ischemia-reperfusion (IR) injury. The aim of our study is to identify lncRNAs related to IR injury and itaconate-mediated protection and to demonstrate the mechanism by which itaconate acts in liver IR injury from the new perspective of lncRNAs.

Methods

4-Octyl itaconate (OI), a membrane-permeable derivative of itaconate, was used as a substitute for itaconate in our study. By using a mouse model of hepatic IR injury, serum and liver samples were collected to measure indexes of liver injury. Then, the liver samples of the mice were subjected to RNA sequencing (RNA-seq) and subsequent bioinformatics analysis.

Results

Itaconate attenuated liver IR injury. A total of 138 lncRNAs and 156 messenger RNAs (mRNAs) were markedly differentially expressed in the IR-damaged liver tissues pretreated with OI compared with the matched liver tissues treated with vehicle. Functional analysis indicated that lncRNAs may indirectly participate in the effects of itaconate. Furthermore, 41 mRNAs were examined for the protein-protein interaction (PPI) network analysis, and a key gene cluster was defined. Then, combined the coexpression analysis and the cis and trans regulatory function prediction of lncRNAs, some "candidate" lncRNA-mRNA pairs which might relate to itaconate-mediated liver protection were identified, while the relationship requires future validation.

Conclusion

Our study revealed that itaconate could protect the liver against IR injury and that lncRNAs might play a role in this process. Our study provides a novel way to investigate the mechanism by which itaconate affects hepatic IR injury and exerts its anti-inflammatory and antioxidative stress effects.

N-acetyl-L-tryptophan attenuates hepatic ischemia-reperfusion injury via regulating TLR4/NLRP3 signaling pathway in rats

The aim of this study was to investigate the changes of TLR4/NLRP3 signal during hepatic ischemia-reperfusion injury (HIRI) and to verify whether N-acetyl-L-tryptophan (L-NAT) protected hepatocytes by regulating the activation of TLR4/NLRP3 signal. We have established the rat HIRI model and H₂O₂-induced cell damage model to simulate ischemia-reperfusion injury and detect the corresponding indicators. Compared with the sham group, Suzuki score and the level of serum ALT increased after HIRI, accompanied by an increased expression of NLRP3, ASC, Caspase-1, IL-1β, TLR4, and NF-κB. While L-NAT pretreatment reversed the above-mentioned changes. Compared with the control group, cells in the H₂O₂ treated group became smaller in cell volume and round in shape with unclear boundaries. Similar to the phenotypes in vivo, H₂O₂ treatment also induced significant increase in expression of pyroptosis-related proteins (NLRP3, ASC, Caspase-1 and IL-1β) and inflammatory factors (TLR4 and NF-κB). While L-NAT pretreatment attenuated injuries caused by H₂O₂. In conclusion, the present findings demonstrate that L-NAT alleviates HIRI by regulating activation of NLRP3 inflammasome, which may be related to the TLR4/NF-κB signaling pathway.

Macrophage extracellular traps aggravate iron overload-related liver ischaemia/reperfusion injury

BACKGROUND AND PURPOSE

Macrophages regulate iron homeostasis in the liver and play important role in hepatic ischaemia/reperfusion (I/R) injury. This study investigates the role of macrophages in iron overload-related hepatocyte damage during liver I/R.

EXPERIMENTAL APPROACH

Liver biopsies from patients undergoing partial hepatectomy with or without hepatic portal occlusion were recruited and markers of hepatocyte cell death and macrophage extracellular traps (METs) were detected. A murine hepatic I/R model was also established in high-iron diet-fed mice. Ferrostatin-1 and deferoxamine were administered to investigate the role of ferroptosis in hepatic I/R injury. The macrophage inhibitor liposome-encapsulated clodronate was used to investigate the interaction between macrophages and ferroptosis. AML12 hepatocytes and RAW264.7 macrophages were co-cultured in vitro. An inhibitor of macrophage extracellular traps was used to evaluate the role and mechanism of these traps and ferroptosis in hepatic I/R injury.

KEY RESULTS

Hepatocyte macrophage extracellular trap formation and ferroptosis were greater in patients who underwent hepatectomy with hepatic portal occlusion and in mice subjected to hepatic I/R. Macrophage extracellular traps increased when macrophages were subjected to hypoxia/reoxygenation and when they were co-cultured with hepatocytes. Ferroptosis increased and post-hypoxic hepatocyte survival decreased, which were reversed by inhibition of macrophage extracellular traps. Ferroptosis inhibition attenuated post-ischaemic liver damage. Moreover, iron overload induced hepatic ferroptosis and exacerbated post-ischaemic liver damage, which were reversed by the iron chelator.

CONCLUSION AND IMPLICATIONS

Macrophage extracellular traps are in volved in regulating ferroptosis highlighting the therapeutic potential of macrophage extracellular traps and ferroptosis inhibition in reducing liver I/R injury.

Role of FGF15 in Hepatic Surgery in the Presence of Tumorigenesis: Dr. Jekyll or Mr. Hyde?

The pro-tumorigenic activity of fibroblast growth factor (FGF) 19 (FGF15 in its rodent orthologue) in hepatocellular carcinoma (HCC), as well as the unsolved problem that ischemia-reperfusion (IR) injury supposes in liver surgeries, are well known. However, it has been shown that FGF15 administration protects against liver damage and regenerative failure in liver transplantation (LT) from brain-dead donors without tumor signals, providing a benefit in avoiding IR injury. The protection provided by FGF15/19 is due to its anti-apoptotic and pro-regenerative properties, which make this molecule a potentially beneficial or harmful factor, depending on the disease. In the present review, we describe the preclinical models currently available to understand the signaling pathways responsible for the apparent controversial effects of FGF15/19 in the liver (to repair a damaged liver or to promote tumorigenesis). As well, we study the potential pharmacological use that has the activation or inhibition of FGF15/19 pathways depending on the disease to be treated. We also discuss whether FGF15/19 non-pro-tumorigenic variants, which have been developed for the treatment of liver diseases, might be promising approaches in the surgery of hepatic resections and LT using healthy livers and livers from extended-criteria donors.

Pyroptosis: mechanisms and diseases

Currently, pyroptosis has received more and more attention because of its association with innate immunity and disease. The research scope of pyroptosis has expanded with the discovery of the gasdermin family. A great deal of evidence shows that pyroptosis can affect the development of tumors. The relationship between pyroptosis and tumors is diverse in different tissues and genetic backgrounds. In this review, we provide basic knowledge of pyroptosis, explain the relationship between pyroptosis and tumors, and focus on the significance of pyroptosis in tumor treatment. In addition, we further summarize the possibility of pyroptosis as a potential tumor treatment strategy and describe the side effects of radiotherapy and chemotherapy caused by pyroptosis. In brief, pyroptosis is a double-edged sword for tumors. The rational use of this dual effect will help us further explore the formation and development of tumors, and provide ideas for patients to develop new drugs based on pyroptosis.

Cadmium and molybdenum co-induce pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells

Cadmium (Cd) and excess molybdenum (Mo) are harmful to animals, but the combined nephrotoxic mechanism of Cd and Mo in duck remains poorly elucidated. To assess joint effects of Cd and Mo on pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells, cells were cultured with 3CdSO₄·8H₂O (4.0 μM), (NH₄)₆Mo₇O₂₄·4H₂O (500.0 μM), MCC950 (10.0 μM), BHA (100.0 μM) and combination of Cd and Mo or Cd, Mo and MCC950 or Cd, Mo and BHA for 12 h, and the joint cytotoxicity was explored. The results manifested that toxicity of non-equitoxic binary mixtures of Mo and Cd exhibited synergic interaction. Mo or/and Cd elevated ROS level, PTEN mRNA and protein levels, and decreased PI3K, AKT and p-AKT expression levels. Simultaneously, Mo or/and Cd upregulated ASC, NLRP3, NEK7, Caspase-1, GSDMA, GSDME, IL-18 and IL-1β mRNA levels and Caspase-1 p20, NLRP3, ASC, GSDMD protein levels, increased the percentage of pyroptotic cells, LDH, NO, IL-18 and IL-1β releases as well as relative conductivity. Moreover, NLRP3 inhibitor MCC950 and ROS scavenger BHA could ameliorate the above changed factors induced by Mo and Cd co-exposure. Collectively, our results reveal that combination of Mo and Cd synergistically cause oxidative stress and trigger pyroptosis via ROS/PTEN/PI3K/AKT axis in duck tubular epithelial cells.

NLRP3 inflammasome priming and activation in cholestatic liver injury via the sphingosine 1-phosphate/S1P receptor 2/Gα(12/13)/MAPK signaling pathway

NLRP3 inflammasome-driven inflammation represents a key trigger for hepatic fibrogenesis during cholestatic liver injury. However, whether sphingosine 1-phosphate (S1P) plays a role in NLRP3 inflammasome priming and activation remains unknown. Here, we found that the expression of NLRP3 in macrophages and NLRP3 inflammasome activation were significantly elevated in the liver injured by bile duct ligation (BDL). In vitro, S1P promoted the NLRP3 inflammasome priming and activation via S1P receptor 2 (S1PR2) in bone marrow-derived monocyte/macrophages (BMMs). Focusing on BMMs, the gene silencing of Gα12 or Gα13 by specific siRNA suppressed NLRP3 inflammasome priming and pro-inflammatory cytokine (IL-1β and IL-18) secretion, whereas Gα(i/o) and Gαq were not involved in this process. The MAPK signaling pathways (P38, ERK, and JNK) mediated NLRP3 inflammasome priming and IL-1β and IL-18 secretion, whereas blockage of PI3K, ROCK, and Rho family had no such effect. Moreover, JTE-013 (S1PR2 inhibitor) treatment markedly reduced NLRP3 inflammasome priming and activation in BDL-injured liver. Collectively, S1P promotes NLRP3 inflammasome priming and pro-inflammatory cytokines (IL-1β and IL-18) secretion via the S1PR2/Gα(12/13)/MAPK pathway, which may represent an effective therapeutic strategy for liver disease. KEY MESSAGE: • Hepatic NLRP3 expression was significantly elevated in BMMs of BDL-injured mouse liver. • S1P promoted NLRP3 inflammasome priming and activation in BMMs, depending on the S1PR2/Gα(12/13)/MAPK pathway. • Blockade of S1PR2 by JTE-013 reduced NLRP3 inflammasome priming and activation inflammasome in vivo.

DHA/AA alleviates LPS-induced Kupffer cells pyroptosis via GPR120 interaction with NLRP3 to inhibit inflammasome complexes assembly

Pyroptosis is a novel type of programmed cell death associated with the pathogenesis of many inflammatory diseases. Docosahexaenoic acid (DHA) and Arachidonic acid (AA) is widely involved in inflammatory pathological processes. However, the effect and mechanism of DHA and AA on pyroptosis in Kupffer cells are poorly understood. The present study demonstrated that DHA and AA ameliorated lipopolysaccharide (LPS)-induced Kupffer cells pyroptosis by reversing the increased expression of NLRP3 inflammasome complex, GSDMD, IL-1β, IL-18, and PI-stained positive rate. Next, the study revealed that GPR120 silencing eliminated the anti-pyroptosis of DHA and AA in LPS-induced Kupffer cells, suggesting that DHA and AA exerted their effect through GPR120 signaling. Importantly, GPR120 endocytose and binds to NLRP3 under LPS stimulation. Furthermore, co-immunoprecipitation showed that DHA and AA promoted the interaction between GPR120 and NLRP3 in LPS-exposed Kupffer cells, thus inhibiting the self-assembly of NLRP3 inflammasome complex. Finally, the study verified that DHA and AA alleviated hepatic injury through inhibiting Kupffer cells pyroptosis in vivo. The findings indicated that DHA and AA alleviated LPS-induced Kupffer cells pyroptosis via GPR120 interaction with NLRP3, it might become a potential therapeutic approach hepatic injury.

Macrophage Regnase-1 Deletion Deteriorates Liver Ischemia/Reperfusion Injury Through Regulation of Macrophage Polarization

Background

Regnase-1 (MCPIP) has been identified as an anti-inflammatory agent, but little is known about its influence on liver ischemia/reperfusion (I/R) injury. Macrophages can evolve biphasic responses and differentiate into remarkable polarizations, contributing greatly to the uncontrolled inflammatory cascades during liver I/R injury. Therefore, the aim of this study was to explore whether regnase-1 participated in liver I/R via manipulating macrophage polarization.

Materials and methods

C57BL/6 mice were randomly divided into five groups: Sham, I/R, Clodronate, Clo + BMDM, and Clo + LV MCPIP BMDM. A liver I/R model was established, and histopathological and immunostaining examinations were performed for the liver specimens; double immunofluorescence staining was used to localize MCPIP in the liver. Primary hepatocytes were isolated to simulate a hypoxia and reoxygenation (H/R) model in vitro. Bone marrow-derived macrophages (BMDM) were extracted and subjected to lentiviral transduction to knockdown MCPIP expression. BMDM with or without MCPIP deletion were exposed to H/R supernatants, and the polarized states were measured by flow cytometry. RT-PCR analysis and Western blot were also conducted.

Results

Compared to those in the Sham group, liver functions and Suzuki’s scores were deteriorated in the I/R group, which were reversed in the Clodronate group. The increased expression of regnase-1 in the I/R group diminished with pretreatment of clodronate liposomes. Subsequent double immunofluorescence staining established the localization of regnase-1 in macrophages in the liver. The insulted lesions in the Clodronate group became progressively aggravated with adoptive transfer of BMDM in the Clo + BMDM group, and they were further exacerbated with the transfusion of BMDM with MCPIP knockdown in the Clo + LV MCPIP BMDM group. Gene expressions of M1 and M2 markers were detected by RT-PCR, suggesting that MCPIP knockdown tended to favor the M1 transformation. Subsequently, ex vivo flow cytometrical detection showed that, upon stimulation by H/R supernatants, LV-MCPIP BMDM posed a higher ratio of M1/M2 than BMDM. Finally, we found that MCPIP participated in macrophage M1/M2 polarization through the NF-κB, C/EBPβ, and PPARγ signaling pathways during liver I/R.

Conclusion

Our study confirms that regnase-1 plays a critical role in liver I/R via regulation of macrophage polarization and, thus, might offer a potential therapeutic target.

MicroRNA-124 regulates cell pyroptosis during cerebral ischemia-reperfusion injury by regulating STAT3

Cerebral ischemia-reperfusion injury (CIRI) is the observed continuation and deterioration of ischemic injury, and currently, there are no effective treatment strategies for the condition. It has been reported that microRNAs (miRNAs) serve an important role in CIRI by regulating pyroptosis. The present study demonstrated that miRNA-124 regulated CIRI by regulating STAT3. To explore the relationship between miRNA-124/STAT3 and pyroptosis in CIRI, CIRI was simulated using a middle cerebral artery occlusion model. Subsequently, miRNA-124 expression levels were altered via the intracerebroventricular injection of miRNA-124 agonist or antagonist. The degree of brain tissue injury was assessed by conducting TTC staining and neurological function scoring. Relative miRNA-124 expression levels were determined via reverse transcription-quantitative PCR. A luciferase reporter gene system verified the targeted binding of miRNA-124 to STAT3. The expression levels of key proteins and proinflammatory cytokines associated with pyroptosis [caspase-1, gasdermin D, interleukin (IL)-18 and IL-1β] were detected via western blotting and immunohistochemistry. The increased expression levels of pyroptosis-associated proteins and proinflammatory cytokines in the I/R groups compared with the control group, indicated that pyroptosis intensified over time during CIRI, and miRNA-124 agonist significantly abrogated pyroptosis and improved neurological function compared with the control group. Furthermore, miRNA-124 inhibited STAT3 activation in a targeted manner, which also decreased the extent of pyroptosis. However, miRNA-124 antagonist reversed miR-124 agonist-mediated effects. Therefore, the present study indicated that miRNA-124 may provide neuroprotection against pyroptosis during CIRI, potentially via inhibition of the STAT3 signaling pathway.

Long Non-Coding RNA (lncRNA) NEAT1 Aggravates Cerebral Ischemia-Reperfusion Injury by Suppressing the Inhibitory Effect of miR-214 on PTEN

Background

Cerebral ischemia-reperfusion injury is a form of serious nervous system injury. Activation of the PI3K/Akt pathway can effectively relieve cerebral ischemia-reperfusion injury. miR-214 can target and inhibit the expression of PTEN, thereby alleviating its inhibitory effect on the PI3K/Akt pathway. Moreover, lncRNA NEAT1 was reported to affect proliferation and metastasis of tumor cells by targeting and suppressing the expression of miR-214. However, whether lncRNA NEAT1 affects the cerebral ischemia-reperfusion-induced damage by regulating the miR-214/PTEN/PI3K/Akt pathway is unclear.

Material/Methods

The miR-214 agomir and miR-214 antagomir were designed and injected into the encephalocele of MCAO rats. Next, the production of oxidative stress kinase and apoptosis of brain cells were detected using commercial kits. The levels of PTEN, PI3K, Akt, p-Akt, and VEGF in brain tissues were determined. Next, the targeting effect of lncRNA NEAT1 and miR-214 was determined with luciferase reporter assay.

Results

Overexpression of miR-214 relieved the apoptosis and oxidative stress of brain tissues. Overexpression of miR-214 promoted the expression of PI3K, Akt, p-Akt, and VEGF by inhibiting the production of PTEN. However, overexpression of lncRNA NEAT1 repressed the remission effect of miR-214 on cerebral ischemia-reperfusion-induced damage and inhibited the production of PI3K, Akt, p-Akt, and VEGF by rescuing the levels of PTEN.

Conclusions

lncRNA NEAT1 aggravates cerebral ischemia-reperfusion injury by abolishing the activation effect of miR-214 on the PI3K/Akt pathway.

The Role of Ischemia/Reperfusion Injury in Early Hepatic Allograft Dysfunction

Liver transplantation (LT) is the only available curative treatment for patients with end-stage liver disease. Early allograft dysfunction (EAD) is a life-threatening complication of LT and is thought to be mediated in large part through ischemia/reperfusion injury (IRI). However, the underlying mechanisms linking IRI and EAD after LT are poorly understood. Most previous studies focused on the clinical features of EAD, but basic research on the underlying mechanisms is insufficient, due, in part, to a lack of suitable animal models of EAD. There is still no consensus on definition of EAD, which hampers comparative analysis of data from different LT centers. IRI is considered as an important risk factor of EAD, which can induce both damage and adaptive responses in liver grafts. IRI and EAD are closely linked and share several common pathways. However, the underlying mechanisms remain largely unclear. Therapeutic interventions against EAD through the amelioration of IRI is a promising strategy, but most approaches are still in preclinical stages. To further study the mechanisms of EAD and promote collaborations between LT centers, optimized animal models and unified definitions of EAD are urgently needed. Because IRI and EAD are closely linked, more attention should be paid to the underlying mechanisms and the fundamental relationship between them. Ischemia/reperfusion-induced adaptive responses may play a crucial role in the prevention of EAD, and more preclinical studies and clinical trials are urgently needed to address the current limitation of available therapeutic interventions.

Hypothermia protects neurons against ischemia/reperfusion-induced pyroptosis via m6A-mediated activation of PTEN and the PI3K/Akt/GSK-3β signaling pathway

Cerebral ischemia/reperfusion (I/R) injury often leads to irreversible neuronal injury and even death, and hypothermia is the only therapeutic method that has been proven to be effective. However, the molecular mechanisms underlying the effect of hypothermia treatment on I/R injury have not been fully elucidated. In the present study, we aimed to evaluate the neuroprotective effects and mechanisms of hypothermia against hypoxia/reoxygenation (H/R)-induced neuronal damage. Primary hippocampal neurons were exposed to H/R and were then treated with hypothermia. We observed that hypothermia significantly increased cellular viability, downregulated the expression of pyroptosis-related proteins-including NLR pyrin domain containing 3 (NLRP3), apoptotic speck-like protein containing CARD (ASC), cleaved Caspase-1, and Gasdermin-D (GsdmD) p30-and reduced secretion of the pro-inflammatory cytokines, IL-1β and IL-18. Additionally, pretreatment with MCC950, a specific small-molecule inhibitor of the NLRP3 inflammasome, yielded a protective effect on cellular viability that was comparable to that of hypothermia treatment. Furthermore, hypothermia also significantly elevated the expression level of phosphatase and tensin homologous protein (PTEN) and activated the phosphorylation levels of protein kinase B (Akt) and glycogen synthase kinase-3β (GSK-3β). These protective effects of hypothermia on pyroptosis-related proteins and pro-inflammatory cytokines were partially reversed by the specific PI3K/Akt inhibitor, LY294002. Moreover, the methylated level of PTEN mRNA was elevated in hippocampal neurons upon H/R, whereas this level remained stable in the hypothermia group. Therefore, our findings suggest that hypothermia protects neurons against neuronal H/R-induced pyroptosis, and that m6A-mediated activation of PTEN and the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt/GSK-3β signaling pathway may play crucial roles during this process.

Perioperative omega-3 fatty acids fail to confer protection in liver surgery: Results of a multicentric, double-blind, randomized controlled trial

BACKGROUND & AIMS

In a variety of animal models, omega-3 polyunsaturated fatty acids (Ω3-FAs) conferred strong protective effects, alleviating hepatic ischemia/reperfusion injury and steatosis, as well as enhancing regeneration after major tissue loss. Given these benefits along with its safety profile, we hypothesized that perioperative administration of Ω3-FAs in patients undergoing liver surgery may ameliorate the postoperative course. The aim of this study was to investigate the perioperative use of Ω3-FAs to reduce postoperative complications after liver surgery.

METHODS

Between July 2013 and July 2018, we carried out a multicentric, double-blind, randomized, placebo-controlled trial designed to test whether 2 single intravenous infusions of Omegaven® (Ω3-FAs) vs. placebo may decrease morbidity. The primary endpoints were postoperative complications by severity (Clavien-Dindo classification) integrated within the comprehensive complication index (CCI).

RESULTS

A total of 261 patients (132 in the Omegaven and 129 in the placebo groups) from 3 centers were included in the trial. Most cases (87%, n = 227) underwent open liver surgery and 56% (n = 105) were major resections (≥3 segments). In an intention-to-treat analysis including the dropout cases, the mortality rate was 4% and 2% in the Omegaven and placebo groups (odds ratio0.40;95% CI 0.04-2.51; p = 0.447), respectively. Any complications and major complications (Clavien-Dindo ≥ 3b) occurred in 46% vs. 43% (p = 0.709) and 12% vs. 10% (p = 0.69) in the Omegaven and placebo groups, respectively. The mean CCI was 17 (±23) vs.14 (±20) (p = 0.417). An analysis excluding the dropouts provided similar results.

CONCLUSIONS

The routine perioperative use of 2 single doses of intravenous Ω3-FAs (100 ml Omegaven) cannot be recommended in patients undergoing liver surgery (Grade A recommendation).

LAY SUMMARY

Despite strong evidence of omega-3 fatty acids having liver-directed, anti-inflammatory and pro-regenerative action in various rodent models, 2 single omega-3 fatty acid infusions given to patients before and during liver surgery failed to reduce complications. Because single omega-3 fatty acid infusions failed to confer liver protection in this trial, they cannot currently be recommended.

TRIAL REGISTRATION

ClinicalTrial.gov: ID: NCT01884948; Institution Ethical Board Approval: KEK-ZH-Nr. 2010-0038; Swissmedic Notification: 2012DR3215.

Inflammasome-Mediated Inflammation in Liver Ischemia-Reperfusion Injury

Ischemia-reperfusion injury is an important cause of liver damage occurring during surgical procedures including hepatic resection and liver transplantation, and represents the main underlying cause of graft dysfunction and liver failure post-transplantation. To date, ischemia-reperfusion injury is an unsolved problem in clinical practice. In this context, inflammasome activation, recently described during ischemia-reperfusion injury, might be a potential therapeutic target to mitigate the clinical problems associated with liver transplantation and hepatic resections. The present review aims to summarize the current knowledge in inflammasome-mediated inflammation, describing the experimental models used to understand the molecular mechanisms of inflammasome in liver ischemia-reperfusion injury. In addition, a clear distinction between steatotic and non-steatotic livers and between warm and cold ischemia-reperfusion injury will be discussed. Finally, the most updated therapeutic strategies, as well as some of the scientific controversies in the field will be described. Such information may be useful to guide the design of better experimental models, as well as the effective therapeutic strategies in liver surgery and transplantation that can succeed in achieving its clinical application.

Role of Thymoquinone in Cardiac Damage Caused by Sepsis from BALB/c Mice

Sepsis is a major health complication causing patient mortality and increased healthcare costs. Cardiac dysfunction, an important consequence of sepsis, affects mortality. We previously reported that thymoquinone (TQ) protected against hyperlipidemia and doxorubicin-induced cardiac damage. This study investigated the possible protective effects of TQ against cardiac damage in septic BALB/c mice. Eight-week-old male BALB/c mice were divided into four groups: control, TQ, cecal ligation and puncture (CLP), and TQ + CLP. CLP was performed after 2-week TQ gavage. After 48 h, we measured the histopathological alterations of the cardiac tissue and the plasma levels of troponin-T (cTnT) and ATP. We evaluated autophagy (p62 and beclin 1), pyroptosis (NLRP3, caspase-1, interleukin [IL]-1β, and IL-18) at the gene and protein levels and IL-6 and tumor necrosis factor-α (TNF-α) at the gene level. Our results demonstrated that TQ administration significantly reduced intestinal histological alterations. TQ inhibited plasma cTnT levels; improved ATP; significantly inhibited p62, NLRP3, caspase-1, IL-1β, IL-18, IL-6, TNF-α, and MCP-1expressions; and increased beclin 1 and IL-10 level. The phosphatidylinositide 3-kinase level was significantly decreased in the TQ + CLP group versus the CLP group. These results suggest that TQ effectively modulates autophagy, pyroptosis, and pro-inflammatory, making it important in the treatment of sepsis-induced cardiac damage.

Coenzyme Q10 protects hepatocytes from ischemia reperfusion-induced apoptosis and oxidative stress via regulation of Bax/Bcl-2/PUMA and Nrf-2/FOXO-3/Sirt-1 signaling pathways

Coenzyme Q₁₀ (CoQ₁₀) is a component of the mitochondrial electron transport chain and regarded as a strong anti-oxidant agent. In this study, we focused on the mechanistic insights involved in the hepato-protective effects of CoQ₁₀ against hepatic ischemia reperfusion (IR) injury. Our results revealed that CoQ₁₀ significantly improved hepatic dysfunctions and oxidative stress caused by IR injury. Interestingly, as compared to IR subjected rat, CoQ₁₀ inhibited apoptosis by marked down-regulation of both Bax and PUMA genes while the level of Bcl-2 gene was significantly increased. Moreover, CoQ₁₀ up-regulated PI3K, Akt and mTOR protein expressions while it inhibited the expression of both GSK-3β and β-catenin. Additionally, CoQ₁₀ restored oxidant/antioxidant balance via marked activated Nrf-2 protein as well as up-regulation of both Sirt-1 and FOXO-3 genes. Moreover, CoQ₁₀ strongly inhibited inflammatory response through down-regulation of NF-κB-p65 and decrease both JAK1 and STAT-3 protein expressions with a subsequent modulating circulating inflammatory cytokines. Furthermore, histopathological analysis showed that CoQ₁₀ remarkably ameliorated the histopathological damage induced by IR injury. Taken together, our results suggested and proved that CoQ₁₀ provided a hepato-protection against hepatic IR injury via inhibition of apoptosis, oxidative stress, inflammation and their closed related pathways.

Role of pyroptosis in cardiovascular diseases

Pyroptosis is a form of programmed necrosis, and is morphologically and mechanistically unique form of programmed cell death compared to others, such as apoptosis and autophagic cell death. More specifically, pyroptosis features gasdermin family-mediated membrane pore formation and subsequent cell lysis, as well as release of pro-inflammatory intracellular contents including IL-1β, IL-18 and HMGB1. Mechanistically, pyroptosis is driven by two main signaling pathways - one mediated by caspase-1 and the other by caspase-4/5/11. Recent studies show that pyroptosis is implicated in several cardiovascular diseases. In this review, we summarize recent scientific discoveries of pyroptosis's involvement in atherosclerosis, myocardial infarction, diabetic cardiomyopathy, reperfusion injury and myocarditis. We also organized new and emerging evidence suggesting that pyroptosis signaling pathways may be potential therapeutic targets in cardiovascular diseases.