Nogo-B is a key mediator of hepatic ischemia and reperfusion injury

A biomimetic nanomedicine alleviates liver transplant-related biliary injury by sequentially inhibiting oxidative stress and regulating macrophage polarization via Nrf-2/HO-1 and JNK pathways

Liver transplantation is an effective method for treating end-stage liver disease. However, 10-20 % of liver transplantation patients develop biliary injury, the main cause of which is ischemia-reperfusion injury (IRI), which consists of oxidative stress injury in the early stage and inflammatory injury in the advanced stage. Biliary injury seriously affects patient outcomes and even leads to mortality, and there are few effective treatments for IRI. Herein, nanoparticles containing quercetin (QR) and rapamycin (RP) coated with poly (lactic-co-glycolic acid) (PLGA) and encapsulated by platelet membrane (PM) were designed to treat IRI in the liver transplantation. The specific binding of ICAM-1 expressed on the PM to integrins (e.g., LFA-1 and Mac-1) in damaged vascular endothelial cells, as well as the interaction between P-selectin on the platelet surface and PSGL-1 on the macrophage surface, allows the accumulation of these biomimetic cell membrane-encapsulated nanoparticles, and subsequently, the delivery of both drugs, to ischemia-reperfusion sites in the liver. The encapsulated QR alleviated oxidative stress injury by activating the Nrf-2/HO-1 signaling pathway in the early stage in model rats with IRI and liver transplantation models. Moreover, RP alleviated inflammatory damage in the advanced stage by suppressing the JNK signaling pathway in M1 macrophages. Thus, these biomimetic nanoparticles that intervene in IRI to alleviate both the early oxidative stress and the advanced inflammatory response constitute a novel delivery system for managing biliary injury after liver transplantation.

Nogo-B Silencing Expedites the Senescence of Platelet-Derived Growth Factor-BB-Induced Human Hepatic Stellate Cells Via Autophagy

Liver fibrosis is a severe liver pathology in response to chronic or iterative liver injury. Senescence has emerged as a protective mechanism against liver fibrosis. Nogo-B has been well established as a significant contributor to liver fibrosis. Nonetheless, researches regarding the role of Nogo-B in cell senescence during liver fibrosis are few. In platelet-derived growth factor-BB (PDGF-BB)-treated human hepatic stellate cell line LX-2, cell proliferation was assayed by CCK-8 method. Western blotting estimated the expression of Nogo-B and fibrosis markers. After Nogo-B was silenced in LX-2 cells pretreated by an autophagy activator Rapamycin and PDGF-BB, CCK-8 method was used to assess cell proliferation. Fibrosis was measured by western blotting and immunofluorescence. Cell cycle was subjected to flow cytometry analysis and cell senescence was evaluated by SA-β-gal staining. Immunofluorescence staining assessed autophagy. Nogo-B was elevated in PDGF-BB-exposed LX-2 cells. Nogo-B silencing suppressed the proliferation, fibrosis, and autophagy while induced cell cycle arrest and senescence of LX-2 cells. Additionally, pretreatment with Rapamycin partially restored the effects of Nogo-B knockdown on the autophagy, proliferation, fibrosis, cell cycle, and senescence of LX-2 cells upon exposure to PDGF-BB. Collectively, inactivation of autophagy mediated by Nogo-B deficiency might elicit protective activities against the development of liver fibrosis.

Met-Exo attenuates pyroptosis in miniature pig liver IRI by improving mitochondrial quality control

Metformin(Met) and adipose-derived stem cell exosomes(ADSCs-Exo) both demonstrate therapeutic effects on mitochondrial dysfunction and pyroptosis. There is also a phenomenon of mutual promotion between these two pathological states. The synergistic effect of metformin-loaded exosomes (Met-Exo) via electroporation in a miniature pig liver ischemia-reperfusion injury (IRI) model remains unexplored. This study established a liver IRI model in miniature pigs to compare the effects of ADSCs-Exo and Met-Exo. We found that Met-Exo intervention better activated the Adenosine 5'-monophosphate activated protein kinase (AMPK)/NAD-dependent deacetylase sirtuin-1(SIRT1) axis, improved mitochondrial dynamics, promoted mitochondrial biogenesis, and inhibited the sustained excessive autophagy of mitochondria after liver IRI. It was then demonstrated that by improving mitochondrial dysfunction, ATP production in liver tissue could be ensured, and ROS generation could be suppressed. This also further inhibited the occurrence of pyroptosis and ensured that mitochondria were protected from gasdermin D-N(GSDMD-N) attack. Met-Exo inhibited the occurrence of pyroptosis through the above pathways, reducing the release of inflammatory factors such as IL-1β and IL-18, and alleviating inflammation. This provides a new therapeutic approach for clinical treatment of liver IRI and improving the success rate of liver transplantation.

Isobutyrate exerts a protective effect against liver injury in a DSS-induced colitis by inhibiting inflammation and oxidative stress

BACKGROUND

Short-chain fatty acids have been reported to have anti-inflammatory and antioxidant functions; whether isobutyrate, a short-chain fatty acid, is protective against liver injury in a dextran sodium sulfate (DSS)-induced colitis and its molecular mechanism is unknown. In this study, DSS was used to induce a liver injury from a colitis model in piglets, which was expected to prevent and alleviate DSS-induced liver injury by feeding sodium isobutyrate in advance.

RESULTS

The results showed that sodium isobutyrate could restore DSS-induced histopathological changes in the liver, inhibit the activation of the toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor kappa-B signaling pathway, and then reduce the DSS-induced release of pro-inflammatory cytokines tumor necrosis factor-α, interleukin 1β, and interleukin 6, reducing inflammatory response. Moreover, we found that sodium isobutyrate could play an antioxidant and apoptosis-reducing role by maintaining reduced mitochondrial function.

CONCLUSION

In conclusion, sodium isobutyrate has a preventive and protective effect on liver injury in a DSS-induced colitis. There is a potential application prospect for it in treating ulcerative-colitis-induced liver injuries. © 2024 Society of Chemical Industry.

The Role of Yes-Associated Protein in Inflammatory Diseases and Cancer

Yes-associated protein (YAP) plays a central role in the Hippo pathway, primarily governing cell proliferation, differentiation, and apoptosis. Its significance extends to tumorigenesis and inflammatory conditions, impacting disease initiation and progression. Given the increasing relevance of YAP in inflammatory disorders and cancer, this study aims to elucidate its pathological regulatory functions in these contexts. Specifically, we aim to investigate the involvement and molecular mechanisms of YAP in various inflammatory diseases and cancers. We particularly focus on how YAP activation, whether through Hippo-dependent or independent pathways, triggers the release of inflammation and inflammatory mediators in respiratory, cardiovascular, and digestive inflammatory conditions. In cancer, YAP not only promotes tumor cell proliferation and differentiation but also modulates the tumor immune microenvironment, thereby fostering tumor metastasis and progression. Additionally, we provide an overview of current YAP-targeted therapies. By emphasizing YAP's role in inflammatory diseases and cancer, this study aims to enhance our understanding of the protein's pivotal involvement in disease processes, elucidate the intricate pathological mechanisms of related diseases, and contribute to future drug development strategies targeting YAP.

CK2α-mediated phosphorylation of DUB3 promotes YAP1 stability and oncogenic functions

The aberrant upregulation of Yes-associated protein 1 (YAP1) in a variety of solid cancers contributes to tumor progression and poor clinical outcomes, rendering it an appealing therapeutic target. However, effective therapies to directly target YAP1 remain challenging. In this study, we perform a high-throughput screening and identify Casein kinase II (CK2) as an uncharacterized upstream regulator of YAP1 turnover in cancer cells of ovarian cancer and several other cancer types. Pharmacological inhibition of Casein kinase II by Silmitasertib or genetic depletion of the catalytic subunit of Casein kinase II (CK2α) markedly destabilizes YAP1 and consequently suppresses its oncogenic functions in vitro and in vivo. Moreover, we reveal that DUB3 as a bona fide deubiquitinase of YAP1, which functionally links CK2 and YAP1 stability in a variety of human cancers. Mechanistically, CK2α directly phosphorylates DUB3 at Thr495, thereby facilitating DUB3-mediated deubiquitination process of YAP1. On the contrary, the loss of Thr495 phosphorylation by the phosphorylation-defective mutant DUB3 T495A, the cancer-related mutant DUB3 D496H and CK2 inhibition failed to deubiquitinate and stabilize YAP1 effectively. Notably, upregulated expressions of CK2α and DUB3 in ovarian cancer positively correlate with YAP1 overexpression. Collectively, our findings demonstrate the functional significance of the CK2α-DUB3 axis in YAP1 stabilization and YAP1-driven tumor progression, highlighting that strategies to target this axis might be of benefit in the clinical management of ovarian cancer and several other lethal cancers with aberrantly upregulated YAP1.

Phosphocreatine ameliorates hepatocellular apoptosis mediated by protecting mitochondrial damage in liver ischemia/reperfusion injury through inhibiting TLR4 and Agonizing Akt Pathway

Hepatic ischemia/reperfusion (HI/R) presents significant challenges in surgical liver transplantation and hepatic ischemic shock, with few effective clinical preventive measures available. This study explores the potential protective effects and underlying mechanisms of phosphocreatine (PCr) in the context of HI/R. We established an in vitro ischemia/reperfusion model using hepatocellular carcinoma HepG2 cells and normal liver L02 cells. For in vivo assessments, C57BL/6 mice were subjected to the HI/R model to evaluate the impact of PCr on liver protection. PCr pretreatment significantly improved liver cell survival rates, maintained mitochondrial membrane potential (MMP), reduced apoptosis, and alleviated oxidative damage and inflammatory responses. Importantly, PCr exerted its protective effects by downregulating TLR4 and activating the Akt signaling pathway, which suppressed inflammation, mitigated oxidative stress, inhibited apoptosis, and modulated key biomarkers, including ALT, AST, IL-6, IL-1β, TNF-α, SOD, MDA, and reactive oxygen species (ROS). Western blot analyses demonstrated PCr's anti-inflammatory effects through the regulation of UCP2, Cyp-D, Cyt-C, and PGC-1α, thereby preserving mitochondrial structure and function, maintaining MMP, and regulating membrane pores. Transmission electron microscopy further highlighted PCr's role in sustaining mitochondrial integrity. In conclusion, our findings suggest that PCr helps maintain mitochondrial homeostasis by intervening in the TLR4 inflammatory pathway and activating the Akt signaling pathway, ultimately reducing liver injury. This study offers new insights and potential treatment strategies for HI/R, providing valuable guidance for future clinical applications.

Current status and perspective on molecular targets and therapeutic intervention strategy in hepatic ischemia-reperfusion injury

Hepatic ischemia‒reperfusion injury (HIRI) is a common and inevitable complication of hepatic trauma, liver resection, or liver transplantation. It contributes to postoperative organ failure or tissue rejection, eventually affecting patient prognosis and overall survival. The pathological mechanism of HIRI is highly complex and has not yet been fully elucidated. The proposed underlying mechanisms include mitochondrial damage, oxidative stress imbalance, abnormal cell death, immune cell hyperactivation, intracellular inflammatory disorders and other complex events. In addition to serious clinical limitations, available antagonistic drugs and specific treatment regimens are still lacking. Therefore, there is an urgent need to not only clarify the exact etiology of HIRI but also reveal the possible reactions and bottlenecks of existing drugs, helping to reduce morbidity and shorten hospitalizations. We analyzed the possible underlying mechanism of HIRI, discussed various outcomes among different animal models and explored neglected potential therapeutic strategies for HIRI treatment. By thoroughly reviewing and analyzing the literature on HIRI, we gained a comprehensive understanding of the current research status in related fields and identified valuable references for future clinical and scientific investigations.

Dual-factor model of sleep and diet: a new approach to understanding central fatigue

Background

Numerous studies have recently examined the impact of dietary factors such as high-fat diets on fatigue. Our study aims to investigate whether high-fat diet (HFD) alone or combined with alternate-day fasting (ADF) can lead to the central fatigue symptoms and to investigate the potential integration of dietary and sleep variables in the development of central fatigue models.

Methods

Seventy-five male Wistar rats were divided into five groups: control, HFD, HFD + ADF, modified multiple platform method (MMPM), and MMPM+HFD + ADF. Each group underwent a 21-day modeling period according to their respective protocol. Their behavioral characteristics, fatigue biochemical markers, hippocampal pathological changes, mitochondrial ultrastructure, and oxidative stress damage were analyzed.

Results

Our findings demonstrate that using only HFD did not cause central fatigue, but combining it with ADF did. This combination led to reduced exercise endurance, decreased locomotor activity, impaired learning and memory abilities, along with alterations in serum levels of alanine aminotransferase (ALT), creatine kinase (CK), and lactate (LAC), as well as hippocampal pathological damage and other central fatigue symptoms. Moreover, the MMPM+HFD + ADF method led to the most obvious central fatigue symptoms in rats, including a variety of behavioral changes, alterations in fatigue-related biochemical metabolic markers, prominent pathological changes in hippocampal tissue, severe damage to the ultrastructure of mitochondria in hippocampal regions, changes in neurotransmitters, and evident oxidative stress damage. Additionally, it was observed that rats subjected to HFD + ADF, MMPM, and MMPM+HFD + ADF modeling method exhibited significant brain oxidative stress damage.

Conclusion

We have demonstrated the promotive role of dietary factors in the development of central fatigue and have successfully established a more stable and clinically relevant animal model of central fatigue by integrating dietary and sleep factors.

XBP1 Facilitating NF-κB-p65 Nuclear Translocation Promotes Macrophage-Originated Sterile Inflammation Via Regulating MT2 Transcription in the Ischemia/Reperfusion Liver

BACKGROUND & AIMS

XBP1, most conserved transcription factor of endoplasmic reticulum stress, plays important roles in physiological and pathologic settings and has profound effects on disease progression and prognosis, so it is necessary to investigate XBP1 in macrophage-originated sterile inflammation during liver ischemia/reperfusion injury (IRI). Macrophage XBP1 expression and liver injury are analyzed in patients undergoing ischemia-related hepatectomy.

METHODS

A myeloid-specific male XBP1-knockout (XBP1M-KO) strain is created for function and mechanism of XBP1 on macrophage-derived sterile inflammation in murine liver IRI with in vitro parallel research. Macrophages cocultured with hypoxia-treated hepatocytes are applied to investigate impact of XBP1 in vitro, with analysis of RNA sequencing and databases.

RESULTS

Clinically, macrophage XBP1 expression significantly increases in ischemic liver tissues and positively correlates with liver injury after hepatectomy. Less hepatocellular damage is presented in XBP1M-KO mice than in XBP1-proficient (XBP1FL/FL) control animals. In vitro, XBP1 deficiency inhibits sterile inflammation and migration in macrophages cocultured with hypoxia-treated hepatocytes. Analysis of RNA sequencing and databases determines Metallothionein 2 (MT2) as XBP1 target gene, negatively regulated by binding with its promoter. XBP1 deficiency increases MT2 and IKBα expression, but inhibits nuclear factor-κB-p65 phosphorylation, markedly neutralizing XBP1M-KO-related benefits by promoting sterile inflammation during liver IRI.

CONCLUSIONS

XBP1 promotes macrophage-originated sterile inflammation, increases liver IRI by binding to MT2 promoter, and regulates MT2/nuclear factor-κB pathway, potentially therapeutic for clinical liver IRI.

Protective effects of Nogo-B deficiency in NAFLD mice and its multiomics analysis of gut microbiology and metabolism

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a prevalent chronic liver ailment that can lead to serious conditions such as cirrhosis and hepatocellular carcinoma. Hepatic Nogo-B regulates glucose and lipid metabolism, and its inhibition has been shown to be protective against metabolic syndrome. Increasing evidence suggests that imbalances in the gut microbiota (GM) and lipid metabolism disorders are significant contributors to NAFLD progression. Nevertheless, it is not yet known whether Nogo-B can affect NAFLD by influencing the gut microbiota and metabolites. Hence, the aim of the present study was to characterize this process and explore its possible underlying mechanisms.

METHODS

A NAFLD model was constructed by administering a high-fat diet (HFD) to Nogo-B-/- and WT mice from the same litter, and body weight was measured weekly in each group. The glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed to assess blood glucose levels. At the end of the 12-week period, samples of serum, liver, and intestinal contents were collected and used for serum biochemical marker and inflammatory factor detection; pathology evaluation; and gut microbiome and metabolomics analysis. Spearman's correlation analysis was performed to determine possible correlations between differential gut microbiota and differential serum metabolites between groups.

RESULTS

Nogo-B deficiency attenuated the effects of the HFD, including weight gain, liver weight gain, impaired glucose tolerance, hepatic steatosis, elevated serum lipid biochemicals levels, and liver function. Nogo-B deficiency suppressed M1 polarization and promoted M2 polarization, thus inhibiting inflammatory responses. Furthermore, Nogo-B-/--HFD-fed mice presented increased gut microbiota richness and diversity, decreased Firmicutes/Bacteroidota (F/B) ratios, and altered serum metabolites compared with those of WT-HFD-fed mice. During analysis, several differential gut microbiota, including Lachnoclostridium, Harryflintia, Odoribacter, UCG-009, and unclassified_f_Butyricoccaceae, were screened between groups. These microbiota were found to be positively correlated with upregulated purine metabolism and bile acid metabolites in Nogo-B deficiency, while they were negatively correlated with downregulated corticosterone and tricarboxylic acid cyclic metabolites in Nogo-B deficiency.

CONCLUSION

Nogo-B deficiency delayed NAFLD progression, as demonstrated by reduced hepatocellular lipid accumulation, attenuated inflammation and liver injury, and ameliorated gut microbiota dysbiosis and metabolic disorders. Importantly, Odoribacter was strongly positively correlated with ALB and taurodeoxycholic acid, suggesting that it played a considerable role in the influence of Nogo-B on the progression of NAFLD, a specific feature of NAFLD in Nogo-B-/- mice. The regulation of bile acid metabolism by the gut microbiota may be a potential target for Nogo-B deficiency to ameliorate NAFLD.

Reducing Nogo-B Improves Hepatic Fibrosis by Inhibiting BACe1-Mediated Autophagy

BACKGROUND

Hepatic fibrosis (HF) is a histopathological change in the process of long-term liver injury caused by cytokine secretion and internal environment disturbance, resulting in excessive liver repair and fiber scar. Nogo-B protein is widely distributed in peripheral tissues and organs and can regulate the migration of endothelial cells by activating TGF-β1 in vascular remodeling after injury. Nogo-B has been shown to promote organ fibrosis. This study was to determine the role of Nogo-B in HF.

METHODS

An HF model was built by intraperitoneal injections with 20% carbon tetrachloride. Localization of Nogo-B was detected by FISH. The interaction between Nogo-B and BACE1 was confirmed by Co-IP. Autophagy flux was analyzed using tandem mRFP-GFP-LC3 fluorescence microscopy, electron microscopy, and western blotting. Detection of serum AST and ALT and H&E staining were utilized to detect the degree of liver injury. The HF was evaluated by Masson trichromatic staining. RT-qPCR, western blotting, and immunofluorescence were employed to detect relevant indicators.

RESULTS

Reducing Nogo-B suppressed AST and ALT levels, the accumulation of collagen I and α-SMA, and expressions of pro-fibrotic genes in mouse liver. BACE1 was a potential downstream target of Nogo-B. Nogo-B was upregulated in TGF-β1-activated hepatic stellate cells (HSCs). Knocking down Nogo-B caused the downregulation of pro-fibrotic genes and inhibited viability of HSCs. Nogo-B knockdown prevented CCL4-induced fibrosis, accompanied by downregulation of extracellular matrix. Nogo-B inhibited HSC autophagy and increased lipid accumulation. BACE1 knockdown inhibited HSC autophagy and activation in LX-2 cells.

CONCLUSION

Nogo-B knockdown prevents HF by directly inhibiting BACe1-mediated autophagy.

Replicating human characteristics: A promising animal model of central fatigue

Central fatigue is a common pathological state characterized by psychological loss of drive, lack of appetite, drowsiness, and decreased psychic alertness. The mechanism underlying central fatigue is still unclear, and there is no widely accepted successful animal model that fully represents human characteristics. We aimed to construct a more clinically relevant and comprehensive animal model of central fatigue. In this study, we utilized the Modified Multiple Platform Method (MMPM) combined with alternate-day fasting (ADF) to create the animal model. The model group rats are placed on a stationary water environment platform for sleep deprivation at a fixed time each day, and they were subjected to ADF treatment. On non-fasting days, the rats were allowed unrestricted access to food. This process was sustained over a period of 21 days. We evaluated the model using behavioral assessments such as open field test, elevated plus maze test, tail suspension test, Morris water maze test, grip strength test, and forced swimming test, as well as serum biochemical laboratory indices. Additionally, we conducted pathological observations of the hippocampus and quadriceps muscle tissues, transmission electron microscope observation of mitochondrial ultrastructure, and assessment of mitochondrial energy metabolism and oxidative stress-related markers. The results revealed that the model rats displayed emotional anomalies resembling symptoms of depression and anxiety, decreased exploratory behavior, decline in learning and memory function, and signs of skeletal muscle fatigue, successfully replicating human features of negative emotions, cognitive decline, and physical fatigue. Pathological damage and mitochondrial ultrastructural alterations were observed in the hippocampus and quadriceps muscle tissues, accompanied by abnormal mitochondrial energy metabolism and oxidative stress in the form of decreased ATP and increased ROS levels. In conclusion, our ADF+MMPM model comprehensively replicated the features of human central fatigue and is a promising platform for preclinical research. Furthermore, the pivotal role of mitochondrial energy metabolism and oxidative stress damage in the occurrence of central fatigue in the hippocampus and skeletal muscle tissues was corroborated.

Alternative splicing and related RNA binding proteins in human health and disease

Alternative splicing (AS) serves as a pivotal mechanism in transcriptional regulation, engendering transcript diversity, and modifications in protein structure and functionality. Across varying tissues, developmental stages, or under specific conditions, AS gives rise to distinct splice isoforms. This implies that these isoforms possess unique temporal and spatial roles, thereby associating AS with standard biological activities and diseases. Among these, AS-related RNA-binding proteins (RBPs) play an instrumental role in regulating alternative splicing events. Under physiological conditions, the diversity of proteins mediated by AS influences the structure, function, interaction, and localization of proteins, thereby participating in the differentiation and development of an array of tissues and organs. Under pathological conditions, alterations in AS are linked with various diseases, particularly cancer. These changes can lead to modifications in gene splicing patterns, culminating in changes or loss of protein functionality. For instance, in cancer, abnormalities in AS and RBPs may result in aberrant expression of cancer-associated genes, thereby promoting the onset and progression of tumors. AS and RBPs are also associated with numerous neurodegenerative diseases and autoimmune diseases. Consequently, the study of AS across different tissues holds significant value. This review provides a detailed account of the recent advancements in the study of alternative splicing and AS-related RNA-binding proteins in tissue development and diseases, which aids in deepening the understanding of gene expression complexity and offers new insights and methodologies for precision medicine.

PPM1G regulates hepatic ischemia/reperfusion injury through STING-mediated inflammatory pathways in macrophages

BACKGROUND

Ischemia/reperfusion injury (IRI) is generally unavoidable following liver transplantation. Here, we investigated the role of protein phosphatase, Mg2+ /Mn2+ dependent 1G (PPM1G) in hepatic IRI.

METHODS

Hepatic IRI was mimicked by employing a hypoxia/reperfusion (H/R) model in RAW 264.7 cells and a 70% warm ischemia model in C57BL/6 mice, respectively. In vitro, expression changes of tumor necrosis factor-α and interleukin were detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blot analysis, and enzyme-linked immunosorbent assay. The protein expressions of PPM1G and the stimulator of interferon genes (STING) pathway components were analyzed by western blot. Interaction between PPM1G and STING was verified by coimmunoprecipitation (CO-IP). Immunofluorescence was applied for detection of p-IRF3. Flow cytometry, qRT-PCR and western blot were utilized to analyze markers of macrophage polarization. In vivo, histological analyses of mice liver were carried out by TUNEL and H&E staining. Changes in serum aminotransferases were also detected.

RESULTS

Following H/R intervention, a steady decline in PPM1G along with an increase in inflammatory cytokines in vitro was observed. Addition of plasmid with PPM1G sequence limited the release of inflammatory cytokines and downregulated phosphorylation of STING. CO-IP validated the interaction between PPM1G and STING. Furthermore, inhibition of PPM1G with lentivirus enhanced phosphorylation of STING and its downstream components; meanwhile, p65, p38, and Jnk were also surged to phosphorylation. Expression of INOS and CD86 was surged, while CD206, Arg-1, and IL-10 were inhibited. In vivo, PPM1G inhibition further promoted liver damage, hepatocyte apoptosis, and transaminases release. Selective inhibition of STING with C-176 partially reversed the activation of STING pathway and inflammatory cytokines in vitro. M1 markers were also suppressed by C-176. In vivo, C-176 rescued liver damage and transaminase release caused by PPM1G inhibition.

CONCLUSION

PPM1G suppresses hepatic IRI and macrophage M1 phenotype by repressing STING-mediated inflammatory pathways.

Inactivation of MST1/2 Controls Macrophage Polarization to Affect Macrophage-Related Disease via YAP and Non-YAP Mechanisms

Macrophage polarization is a critical process that regulates in inflammation, pathogen defense, and tissue repair. Here we demonstrate that MST1/2, a core kinase of Hippo pathway and a recently identified regulator of inflammation, plays a significant role in promoting M2 polarization. We provide evidence that inhibition of MST1/2, achieved through either gene-knockout or pharmacological treatment, leads to increased M1 polarization in a YAP-dependent manner, resulting in the development of M1-associated inflammatory disorders. Moreover, MST1/2 inhibition also leads to a substantial reduction in M2 polarization, but this occurs through the STAT6 and MEK/ERK signaling. The STAT6 is independent of YAP, but MEK/ERK is dependent of YAP. Consistent with these observations, both MST1/2-conditional knockout mice and wild-type mice treated with XMU-MP-1, a chemical inhibitor of MST1/2, exhibited reduced M2-related renal fibrosis, while simultaneously displaying enhanced LPS-mediated inflammation and improved clearance of MCR3-modified gram-negative bacteria. These findings uncover a novel role of MST1/2 in regulating macrophage polarization and establish it as a potential therapeutic target for the treatment of macrophage-related fibrotic diseases.

Role of the immune system in liver transplantation and its implications for therapeutic interventions

Liver transplantation (LT) stands as the gold standard for treating end-stage liver disease and hepatocellular carcinoma, yet postoperative complications continue to impact survival rates. The liver's unique immune system, governed by a microenvironment of diverse immune cells, is disrupted during processes like ischemia-reperfusion injury posttransplantation, leading to immune imbalance, inflammation, and subsequent complications. In the posttransplantation period, immune cells within the liver collaboratively foster a tolerant environment, crucial for immune tolerance and liver regeneration. While clinical trials exploring cell therapy for LT complications exist, a comprehensive summary is lacking. This review provides an insight into the intricacies of the liver's immune microenvironment, with a specific focus on macrophages and T cells as primary immune players. Delving into the immunological dynamics at different stages of LT, we explore the disruptions after LT and subsequent immune responses. Focusing on immune cell targeting for treating liver transplant complications, we provide a comprehensive summary of ongoing clinical trials in this domain, especially cell therapies. Furthermore, we offer innovative treatment strategies that leverage the opportunities and prospects identified in the therapeutic landscape. This review seeks to advance our understanding of LT immunology and steer the development of precise therapies for postoperative complications.

Regulatory mechanism of macrophage polarization based on Hippo pathway

Macrophages are found to infiltrate and migrate in a large number of Tumor-associated macrophages (TMEs) and other macrophages in the microenvironment of tumors and related diseases, and undergo phenotypic changes in response to a variety of cytokines, mainly including the primary phenotype M2 and the anti-tumor phenotype M1. The Hippo signaling pathway affects the development of cancer and other diseases through various biological processes, such as inhibition of cell growth. In this review, we focus on immune cells within the microenvironment of tumors and other diseases, and the role of the Hippo pathway in tumors on macrophage polarization in the tumor microenvironment (TME) and other diseases.

ROS/RNS as molecular signatures of chronic liver diseases

The liver can succumb to oxidant damage during the development of chronic liver diseases. Despite their physiological relevance to hepatic homeostasis, excessive reactive oxygen/nitrogen species (ROS/RNS) production under pathological conditions is detrimental to all liver constituents. Chronic oxidative stress coupled to unresolved inflammation sets in motion the activation of profibrogenic hepatic stellate cells (HSCs) and later pathogenesis of liver fibrosis, cirrhosis, and liver cancer. The liver antioxidant and repair systems, along with autophagic and ferroptotic machineries, are implicated in the onset and trajectory of disease development. In this review, we discuss the ROS/RNS-related mechanisms underlying liver fibrosis of distinct etiologies and highlight preclinical and clinical trials of antifibrotic therapies premised on remediating oxidative/nitrosative stress in hepatocytes or targeting HSC activation.

Nogo-B inhibition restricts ulcerative colitis via inhibiting p68/miR-155 signaling pathway

BACKGROUND & AIMS

Ulcerative colitis (UC) is a main type of inflammatory bowel diseases which spreads globally during the westernization of lifestyle over the past few decades. However, the cause of UC is still not fully understood. We aimed to disclose the role of Nogo-B in the development of UC.

METHODS

Nogo-deficiency (Nogo^-/-) and wild-type male mice were treated with dextran sodium sulfate (DSS) to conduct a UC model, followed by determination of colon and serum inflammatory cytokines level. RAW264.7, THP1 and NCM460 cells were used to determine macrophage inflammation as well as proliferation and migration of NCM460 cells under Nogo-B or miR-155 intervention.

RESULTS

Nogo deficiency significantly reduced DSS-induced weight loss, colon length and weight reduction, and inflammatory cells accumulation in the intestinal villus, while increased the expression of tight junctions (TJs) proteins (Zonula occludens-1, Occludin) and adherent junctions (AJs) proteins (E-cadherin, α-catenin), implying that Nogo deficiency attenuated DSS-induced UC. Mechanistically, Nogo-B deficiency reduced TNFα, IL-1β and IL-6 levels in the colon, serum, RAW264.7 cells and THP1-derived macrophages. Furthermore, we identified that Nogo-B inhibition can reduce the maturation of miR-155, which is essential for Nogo-B-affected inflammatory cytokines expression. Interestingly, we determined that Nogo-B and p68 can interact with each other to promote the expression and activation of Nogo-B and p68, thus facilitating miR-155 maturation to induce macrophage inflammation. Blocking p68 inhibited Nogo-B, miR-155, TNFα, IL-1β and IL-6 expression. Moreover, the culture medium collected from Nogo-B overexpressed macrophages can inhibit enterocytes NCM460 cells proliferation and migration.

CONCLUSION

We disclose that Nogo deficiency reduced DSS-induced UC via inhibiting p68-miR-155-activated inflammation. Our results indicate that Nogo-B inhibition serves as a new potential therapeutic candidate for the prevention and treatment of UC.

PPARγ Regulates Macrophage Polarization by Inhibiting the JAK/STAT Pathway and Attenuates Myocardial Ischemia/Reperfusion Injury In Vivo

This study aimed to investigate the role of PPARγ and underlying mechanisms in myocardial ischemia/reperfusion injury (IRI). IRI was surgically induced in mice and neonatal rat cardiomyocytes (NRCM) were exposed to oxygen-glucose deprivation and reoxygenation (OGD/R). Quantitative genetic analysis and western blotting were performed to assess mRNA and protein levels, respectively, of PPARγ, as well as of different inflammatory, fibrosis, and apoptosis markers in cells and tissues. PPARγ was overexpressed in the heart of mice and NRCMs by viral transfection. Apoptosis and fibrosis were detected by TUNEL and Masson's trichrome staining, respectively. Enzyme-linked immunosorbent assay was performed to detect M1 and M2 macrophage-related inflammatory factors present in mouse sera. PPARγ overexpression significantly inhibited OGD/R- and IRI-induced cardiomyocyte apoptosis and fibrosis in vitro and in vivo. Moreover, PPARγ overexpression inhibited IRI-induced secretion of M1-related proinflammatory factors, whereas it supported the secretion of M2-related anti-inflammatory factors. Notably, these events were found to be mediated by the JAK/STAT pathway. In conclusion, PPARγ regulates macrophage polarization upon IRI via the JAK/STAT pathway, which will in turn prevent myocardial apoptosis and fibrosis. Hence, PPARγ may represent a valuable target for myocardial IRI treatment.

Mitochondrial unfolded protein response in ischemia-reperfusion injury

Mitochondrial unfolded protein response (UPRmt) is a mitochondrial stress response that activates the transcriptional program of mitochondrial chaperone proteins and proteases to keep protein homeostasis in mitochondria. Ischemia-reperfusion injury results in multiple severe clinical issues linked to high morbidity and mortality in various disorders. The pathophysiology and pathogenesis of ischemia-reperfusion injury are complex and multifactorial. Emerging evidence showed the roles of UPRmt signaling in ischemia-reperfusion injury. Herein, we discuss the regulatory mechanisms underlying UPRmt signaling in C. elegans and mammals. Furthermore, we review the recent studies into the roles and mechanisms of UPRmt signaling in ischemia-reperfusion injury of the heart, brain, kidney, and liver. Further research of UPRmt signaling will potentially develop novel therapeutic strategies against ischemia-reperfusion injury.

Deficiency of MST1 in endometriosis related peritoneal macrophages promoted the autophagy of ectopic endometrial stromal cells by IL-10

Changes in the function of peritoneal macrophages contribute to the homeostasis of the peritoneal immune microenvironment in endometriosis. The mechanism by which ectopic tissues escape phagocytic clearance by macrophages to achieve ectopic colonization and proliferation is unknown. The expression of CD163 in peritoneal macrophages in patients with endometriosis is increased, with the overexpression of MAPK, which can promote the M2-type polarization of macrophages and reduce their ability to phagocytose ectopic endometrial cells. As an upstream regulator of MAPK, MST1 expression is deficient in peritoneal macrophages of patients with endometriosis. This process is regulated by miR-887-5p, a noncoding RNA targeting MST1. Moreover, MST1-knockout macrophages secrete anti-inflammatory factor IL-10, which promotes autophagy of ectopic endometrial stromal cells. These results suggest that MST1 deficient macrophages may accelerate the autophagy of ectopic endometrium via IL-10 which was regulated by miR-887-5p.

The Hippo-YAP pathway in various cardiovascular diseases: Focusing on the inflammatory response

The Hippo pathway was initially discovered in Drosophila melanogaster and mammals as a key regulator of tissue growth both in physiological and pathological states. Numerous studies depict the vital role of the Hippo pathway in cardiovascular development, heart regeneration, organ size and vascular remodeling through the regulation of YAP (yes-associated protein) translocation. Recently, an increasing number of studies have focused on the Hippo-YAP pathway in inflammation and immunology. Although the Hippo-YAP pathway has been revealed to play controversial roles in different contexts and cell types in the cardiovascular system, the mechanisms regulating tissue inflammation and the immune response remain to be clarified. In this review, we summarize findings from the past decade on the function and mechanism of the Hippo-YAP pathway in CVDs (cardiovascular diseases) such as myocardial infarction, cardiomyopathy and atherosclerosis. In particular, we emphasize the role of the Hippo-YAP pathway in regulating inflammatory cell infiltration and inflammatory cytokine activation.

Roles of Yes-associated protein and transcriptional coactivator with PDZ-binding motif in non-neoplastic liver diseases

The prevalence of liver disease has been increasing worldwide. Moreover, the burden of end-stage liver disease, including cirrhosis and liver cancer, is high because of high mortality and suboptimal treatment. The pathological process of liver disease includes steatosis, hepatocyte death, and fibrosis, which ultimately lead to cirrhosis and liver cancer. Clinical and preclinical evidence indicates that non-neoplastic liver diseases, particularly cirrhosis, are major risk factors for liver cancer, although the mechanism underlying this association remains unclear. Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are transcriptional activators that regulate organ size and cancer development. YAP and TAZ play important roles in liver development, regeneration, and homeostasis. Abnormal YAP and TAZ levels have also been implicated in non-neoplastic liver diseases (e.g., non-alcoholic fatty liver disease, alcoholic liver disease, liver injury, and liver fibrosis). Here, we review recent findings on the roles of YAP and TAZ in non-neoplastic liver diseases and discuss directions for future research. This review provides a basis for the study of non-neoplastic liver diseases.

Macrophage nuclear factor erythroid 2-related factor 2 deficiency promotes innate immune activation by tissue inhibitor of metalloproteinase 3-mediated RhoA/ROCK pathway in the ischemic liver

BACKGROUND AND AIMS

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of reactive oxygen species (ROS) and inflammation and has been implicated in both human and murine inflammatory disease models. We aimed to characterize the roles of macrophage-specific Nrf2 in liver ischemia/reperfusion injury (IRI).

APPROACH AND RESULTS

First, macrophage Nrf2 expression and liver injury in patients undergoing OLT or ischemia-related hepatectomy were analyzed. Subsequently, we created a myeloid-specific Nrf2-knockout (Nrf2M-KO ) strain to study the function and mechanism of macrophage Nrf2 in a murine liver IRI model. In human specimens, macrophage Nrf2 expression was significantly increased in liver tissues after transplantation or hepatectomy. Interestingly, lower Nrf2 expressions correlated with more severe liver injury postoperatively. In a mouse model, we found Nrf2M-KO mice showed worse hepatocellular damage than Nrf2-proficient controls based on serum biochemistry, pathology, ROS, and inflammation. In vitro, Nrf2 deficiency promoted innate immune activation and migration in macrophages on toll-like receptor (TLR) 4 stimulation. Microarray profiling showed Nrf2 deletion caused markedly lower transcriptional levels of tissue inhibitor of metalloproteinase 3 (Timp3). ChIP-seq, PCR, and luciferase reporter assay further demonstrated Nrf2 bound to the promoter region of Timp3. Moreover, a disintegrin and metalloproteinase (ADAM) 10/ROCK1 was specifically increased in Nrf2-deficient macrophages. Increasing Timp3 expression effectively inhibited ADAM10/ROCK1 expression and rescued the Nrf2M-KO -mediated inflammatory response on TLR4 stimulation in vitro. Importantly, Timp3 overexpression, recombinant Timp3 protein, or ROCK1 knockdown rescued Nrf2M-KO -related liver IRI by inhibiting macrophage activation.

CONCLUSIONS

In conclusion, macrophage Nrf2 mediates innate proinflammatory responses, attenuates liver IRI by binding to Timp3, and inhibits the RhoA/ROCK pathway, which provides a therapeutic target for clinical organ IRI.

Inhibition of HMGB1 Ameliorates the Maternal-Fetal Interface Destruction in Unexplained Recurrent Spontaneous Abortion by Suppressing Pyroptosis Activation

Recurrent spontaneous abortion (RSA) is a common complication of pregnancy that affects the physical and mental health of pregnant women, and approximately 50% of the mechanisms are unclear. Our previous studies have found that high mobility group box 1 (HMGB1) molecules are highly expressed at the maternal-fetal interface of unexplained recurrent spontaneous abortion (URSA) patients. The purpose of this study was to further detect the expression of HMGB1 and pyroptosis in decidual tissue of URSA patients, and explore the potential mechanism of the protective role of HMGB1 in URSA patients and mouse model. The decidua tissues of 75 URSA patients and 75 women who actively terminated pregnancy were collected, and URSA mouse models were established and treated with HMGB1 inhibitor-aspirin. The expression of HMGB1, and their receptors (RAGE, TLR2, TLR4), pyroptosis-associated proteins (NLRP-3, caspase-1, GSDMD) and NF-κB was examined at the maternal-fetal interface of human and mouse. Our study found that HMGB1, NLRP-3, Caspase-1, GSDMD, RAGE, TLR2 and TLR4 were highly expressed and NF-κB signaling pathway were activated in the decidua tissue of URSA group. Moreover, immune cell disorder and co-localization of HMGB1 and macrophages were found at the maternal-fetal interface of URSA mice. However, HMGB1, TLR2, TLR4, NF-κB, and pyroptosis-associated proteins can be down-regulated by administering low-dose aspirin. These data may indicate that highly expressed HMGB1 was actively secreted by macrophages and then activated pyroptosis through the TLR2/TLR4-NF-κB pathway to cause aseptic inflammation, leading to the occurrence and development of URSA. Moreover, low-dose aspirin can reduce HMGB1 protein levels of serum and decidual in URSA.

Harnessing reactive oxygen/nitrogen species and inflammation: Nanodrugs for liver injury

Overall, 12% of the global population (800 million) suffers from liver disease, which causes 2 million deaths every year. Liver injury involving characteristic reactive oxygen/nitrogen species (RONS) and inflammation plays a key role in progression of liver disease. As a key metabolic organ of the human body, the liver is susceptible to injury from various sources, including COVID-19 infection. Owing to unique structural features and functions of the liver, most current antioxidants and anti-inflammatory drugs are limited against liver injury. However, the characteristics of the liver could be utilized in the development of nanodrugs to achieve specific enrichment in the liver and consequently targeted treatment. Nanodrugs have shown significant potential in eliminating RONS and regulating inflammation, presenting an attractive therapeutic tool for liver disease through controlling liver injury. Therefore, the main aim of the current review is to provide a comprehensive summary of the latest developments contributing to our understanding of the mechanisms underlying nanodrugs in the treatment of liver injury via harnessing RONS and inflammation. Meanwhile, the prospects of nanodrugs for liver injury therapy are systematically discussed, which provides a sound platform for novel therapeutic insights and inspiration for design of nanodrugs to treat liver disease.