LPS-induced macrophage HMGB1-loaded extracellular vesicles trigger hepatocyte pyroptosis by activating the NLRP3 inflammasome

Exosomes Derived from Apelin-Pretreated Mesenchymal Stem Cells Ameliorate Sepsis-Induced Myocardial Dysfunction by Alleviating Cardiomyocyte Pyroptosis via Delivery of miR-34a-5p

Background

Exosomes sourced from mesenchymal stem cells (MSC-EXOs) have become a promising therapeutic tool for sepsis-induced myocardial dysfunction (SMD). Our previous study demonstrated that Apelin pretreatment enhanced the therapeutic benefit of MSCs in myocardial infarction by improving their paracrine effects. This study aimed to determine whether EXOs sourced from Apelin-pretreated MSCs (Apelin-MSC-EXOs) would have potent cardioprotective effects against SMD and elucidate the underlying mechanisms.

Methods

MSC-EXOs and Apelin-MSC-EXOs were isolated and identified. Mice neonatal cardiomyocytes (NCMs) were treated with MSC-EXOs or Apelin-MSC-EXOs under lipopolysaccharide (LPS) condition in vitro. Cardiomyocyte pyroptosis was determined by TUNEL staining. RNA sequencing was used to identify differentially expressed functional miRNAs between MSC-EXOs and Apelin-MSC-EXOs. MSC-EXOs and Apelin-MSC-EXOs were transplanted into a mouse model of SMD induced by cecal ligation puncture (CLP) via the tail vein. Heart function was evaluated by echocardiography.

Results

Compared with MSC-EXOs, Apelin-MSC-EXO transplantation greatly enhanced cardiac function in SMD mice. Both MSC-EXOs and Apelin-MSC-EXOs suppressed cardiomyocyte pyroptosis in vivo and in vitro, with the latter exhibiting superior protective effects. miR-34a-5p effectively mediated Apelin-MSC-EXOs to exert their cardioprotective effects in SMD with high mobility group box-1 (HMGB1) as the potential target. Mechanistically, Apelin-MSC-EXOs delivered miR-34a-5p into injured cardiomyocytes, thereby ameliorating cardiomyocyte pyroptosis via regulation of the HMGB1/AMPK axis. These cardioprotective effects were partially abrogated by downregulation of miR-34a-5p in Apelin-MSC-EXOs.

Conclusion

Our study revealed miR-34a-5p as a key component of Apelin-MSC-EXOs that protected against SMD via mediation of the HMGB1/AMPK signaling pathway.

Bruceine A attenuates fibrogenesis and inflammation through NR2F2-regulated HMGB1 inflammatory signaling cascades in hepatic fibrosis

This investigation explored the hepatoprotective capabilities of Bruceine A (BA) and its underlying mechanisms in mitigating hepatic fibrosis. Hepatic stellate cells (HSCs) and mouse primary hepatocytes were treated with TGF-β and subsequently exposed to BA. To assess the effects of BA on the NR2F2-HMGB1 signaling cascade, these cells underwent transfection with a siRNA vector targeting NR2F2. The interaction between NR2F2 and the HMGB1 promoter was elucidated using a dual luciferase assay. In vivo, C57BL/6 mice were treated with thioacetamide (TAA) to induce liver damage, followed by administration of BA. The study found that BA moderated extracellular matrix (ECM) buildup, epithelial-mesenchymal transition (EMT), and inflammatory mediator levels, while concurrently reducing NR2F2 and HMGB1 expression in activated HSCs. Furthermore, BA lessened pyroptosis in hepatocytes, curtailing the inflammatory response. The absence of NR2F2 in HSCs or hepatocytes hindered BA's inhibitory effect on this pathway. It was demonstrated that NR2F2 binds directly to the HMGB1 promoter. Treatment with BA resulted in diminished serum levels of ALT and AST, mitigated damage in hepatic tissues, and decreased the ECM and neutrophil extracellular traps (NETs), thus protecting hepatocytes from fibrosis. Furthermore, BA suppressed the synthesis of inflammatory mediators such as NLRP3, caspase-1, and IL-1β by blocking the NR2F2-driven HMGB1 pathway, markedly reversing hepatic fibrosis. These observations highlight the efficacy of BA as a viable therapeutic candidate for hepatic fibrosis.

Mitochondrial dysfunction is a major cause of thromboinflammation and inflammatory cell death in critical illnesses

BACKGROUND

Mitochondria generate the adenosine triphosphate (ATP) necessary for eukaryotic cells, serving as their primary energy suppliers, and contribute to host defense by producing reactive oxygen species. In many critical illnesses, including sepsis, major trauma, and heatstroke, the vicious cycle between activated coagulation and inflammation results in tissue hypoxia-induced mitochondrial dysfunction, and impaired mitochondrial function contributes to thromboinflammation and cell death.

METHODS

A computer-based online search was performed using the PubMed and Web of Science databases for published articles concerning sepsis, trauma, critical illnesses, cell death, mitochondria, inflammation, coagulopathy, and organ dysfunction.

RESULTS

Mitochondrial outer membrane permeabilization triggers apoptosis by releasing cytochrome c and activating caspases. Apoptosis is a non-inflammatory programmed cell death but requires sufficient ATP supply. Therefore, conversion to inflammatory necrosis may occur due to a lack of ATP in critical illness. Severely damaged mitochondria release excess reactive oxygen species and injurious mitochondrial DNA, inducing cell death. Besides non-programmed necrosis, mitochondrial damage can trigger programmed inflammatory cell death, including necroptosis, pyroptosis, and ferroptosis. Additionally, a unique form of DNA-ejecting cell death, known as etosis, occurs in monocytes and granulocytes following external stimuli and mitochondrial damage. The type of cell death chosen remains uncertain but is known to depend on the cell type, the nature of the injury, and the degree of damage.

CONCLUSIONS

Mitochondria damage is the major contributor to the cell death mechanism that leads to organ damage in critical illnesses. Regulating and restoring mitochondrial function holds promise for developing new therapeutic approaches for mitigating critical diseases.

Emerging Roles of High-mobility Group Box-1 in Liver Disease

High-mobility group box-1 (HMGB1) is an architectural chromosomal protein with various roles depending on its cellular localization. Extracellular HMGB1 functions as a prototypical damage-associated molecular pattern that triggers inflammation and adaptive immune responses, mediated by specific cell surface receptors, including receptors for advanced glycation end products and toll-like receptors. Post-translational modifications of HMGB1 significantly impact various cellular processes that contribute to the pathogenesis of liver diseases. Recent studies have highlighted the close relationship between HMGB1 and the pathogenesis of acute liver injuries, including acetaminophen-induced liver injury, hepatic ischemia-reperfusion injury, and acute liver failure. In chronic liver diseases, HMGB1 plays a role in nonalcoholic fatty liver disease, alcohol-associated liver disease, liver fibrosis, and hepatocellular carcinoma. Targeting HMGB1 as a therapeutic approach, either by inhibiting its release or blocking its extracellular function, is a promising strategy for treating liver diseases. This review aimed to summarize the available evidence on HMGB1's role in liver disease, focusing on its multifaceted signaling pathways, impact on disease progression, and the translation of these findings into clinical interventions.

The role of macrophage-derived exosomes in noncancer liver diseases: From intercellular crosstalk to clinical potential

Chronic liver disease has a substantial global prevalence and mortality rate. Macrophages, pivotal cells in innate immunity, exhibit remarkable heterogeneity and plasticity and play a considerable role in maintaining organ homeostasis, modulating inflammatory responses, and influencing disease progression in the liver. Exosomes, which can serve as conduits for intercellular communication, biomarkers, and therapeutic targets for a spectrum of diseases, have recently garnered increasing attention recently. Given that the liver is the organ with the highest macrophage content, a thorough understanding of the influence of macrophage-derived exosomes (MDEs) on noncancer liver disease pathogenesis and their potential therapeutic applications is paramount. Interactions among MDEs, hepatocytes, hepatic stellate cells (HSCs), and other nonparenchymal cells constitute a complex network regulates liver immune homeostasis. In this review, we summarize the latest progress in the current understanding of MDE heterogeneity and cellular crosstalk in noncancer liver diseases, as well as their potential clinical applications. Additionally, challenges and future directions are underscored.

Protocol for isolating extracellular vesicles from alveolar macrophages phagocytosing MRSA in vitro cell culture models

Extracellular vesicles (EVs) play a crucial role in delivering bioactive cargo in infectious diseases. Here, we present a protocol for isolating EVs from alveolar macrophages (AMs) that phagocytose methicillin-resistant Staphylococcus aureus (MRSA) in vitro cell culture models. We describe steps for bacterial preparation; infection of AMs with MRSA; and isolation, purification, and characterization of EVs. This protocol provides a valuable perspective for studying EVs derived from pathogen-infected immune cells. For complete details on the use and execution of this protocol, please refer to Bai et al.1.

SNHG12 in cancer-associated fibroblast-derived extracellular vesicle induces macrophage-myofibroblast transition

AIMS

To investigate mechanism of lncRNA SNHG12 induced macrophage-myofibroblast transition (MMT) in cancer-associated fibroblasts (CAFs)-derived extracellular vesicles (EVs) in non-small cell lung cancer (NSCLC).

METHOD

CAFs EVs were isolated from human NSCLC tissue and adjacent cancerous tissue (n = 3), and their morphology and particle size were evaluated. Macrophages and MMT cells with different phenotypes were detected, and the binding relationship of lncRNA SNHG12, miR-181a-5p, and Smad3 was verified.

RESULT

LncRNA SNHG12 derived from CAFs-EVs promoted the transformation of M2 macrophages into MMT. In addition, lncRNA-SNHG12 increased the expression of Smad3 which was significantly upregulated in MMT through sponge of miR-181a-5p.

CONCLUSION

LncRNA SNHG12 derived from CAFs-EV induced MMT in NSCLC.

Pyroptosis in Endothelial Cells and Extracellular Vesicle Release in Atherosclerosis via NF-κB-Caspase-4/5-GSDM-D Pathway

Background: Pyroptosis, an inflammatory cell death, is involved in the progression of atherosclerosis. Pyroptosis in endothelial cells (ECs) and its underlying mechanisms in atherosclerosis are poorly understood. Here, we investigated the role of a caspase-4/5-NF-κB pathway in pyroptosis in palmitic acid (PA)-stimulated ECs and EVs as players in pyroptosis. Methods: Human umbilical vein endothelial cells (HUVECs) were cultured in an endothelial cell medium, treated with Ox-LDL, PA, caspase-4/5 inhibitor, NF-κB inhibitor, and sEV release inhibitor for 24 h, respectively. The cytotoxicity of PA was determined using an MTT assay, cell migration using a scratch-wound-healing assay, cell morphology using bright field microscopy, and lipid deposition using oil red O staining. The mRNA and protein expression of GSDM-D, CASP4, CASP5, NF-κB, NLRP3, IL-1β, and IL-18 were determined with RT-PCR and Western blot. Immunofluorescence was used to determine NLRP3 and ICAM-1 expressions. Extracellular vesicles (EVs) were isolated using an exosome isolation kit and were characterized by Western blot and scanning electron microscopy. Results: PA stimulation significantly changed the morphology of the HUVECs characterized by cell swelling, plasma membrane rupture, and increased LDH release, which are features of pyroptosis. PA significantly increased lipid accumulation and reduced cell migration. PA also triggered inflammation and endothelial dysfunction, as evidenced by NLRP3 activation, upregulation of ICAM-1 (endothelial activation marker), and pyroptotic markers (NLRP3, GSDM-D, IL-1β, IL-18). Inhibition of caspase-4/5 (Ac-FLTD-CMK) and NF-κB (trifluoroacetate salt (TFA)) resulted in a significant reduction in LDH release and expression of caspase-4/5, NF-κB, and gasdermin D (GSDM-D) in PA-treated HUVECs. Furthermore, GW4869, an exosome release inhibitor, markedly reduced LDH release in PA-stimulated HUVECs. EVs derived from PA-treated HUVECs exacerbated pyroptosis, as indicated by significantly increased LDH release and augmented expression of GSDM-D, NF-κB. Conclusions: The present study revealed that inflammatory, non-canonical caspase-4/5-NF-κB signaling may be one of the crucial mechanistic pathways associated with pyroptosis in ECs, and pyroptotic EVs facilitated pyroptosis in normal ECs during atherosclerosis.

Paeoniflorin regulates microglia-astrocyte crosstalk, inhibits inflammatory response, and alleviates neuropathic pain through HSP90AA1/HMGB1 signaling pathway

Given the unclear, complex pathogenesis of neuropathic pain and the potential of paeoniflorin in relieving neuropathic pain, this study aimed to further clarify the therapeutic effect of paeoniflorin on neuropathic pain and to preliminarily explore the possible protective mechanisms of paeoniflorin. Chronic constrictive injury-induced Sprague Dawley rats and lipopolysaccharide-induced BV-2 cells were used for in vivo and in vitro experiments, respectively. The exosome uptake assay of mouse astrocytes (PKH-67 fluorescent labeling) and the mechanical nociceptive assay (the von Frey fibrous filaments) were performed. The effects of paeoniflorin and its downstream mechanisms on microglial and astrocyte activation, inflammation-associated proteins and exosome marker were determined. Paeoniflorin alleviated mechanical abnormal pain, decreased levels of ionized calcium binding adapter molecule-1 (Iba-1), glial fibrillary acidic protein, Heat Shock Protein 90 Alpha Family Class A Member 1 (HSP90AA1, inflammatory factor) and High Mobility Group Box 1 (HMGB1, inflammation-related protein), and inhibited neuronal apoptosis in chronic constrictive injury rats or lipopolysaccharide-induced BV-2 cells. However, these effects were offset by HSP90AA1 overexpression in lipopolysaccharide-induced BV-2 cells. Exosomes of BV-2 cells could be absorbed by mouse astrocytes. In addition, HSP90AA1 overexpression reversed the effects of paeoniflorin on HMGB1 expression and inflammatory factors and proteins in mouse astrocytes co-cultured with exosome. Collectively, paeoniflorin alleviates neuropathic pain and inhibits inflammatory responses in chronic constrictive injury by modulating microglia-astrocyte crosstalk through HSP90AA1/HMGB1 pathways, which further evidences the potential of paeoniflorin in the treatment of neuropathic pain.

The dysfunction of complement and coagulation in diseases: the implications for the therapeutic interventions

The complement system, comprising over 30 proteins, is integral to the immune system, and the coagulation system is critical for vascular homeostasis. The activation of the complement and coagulation systems involves an organized proteolytic cascade, and the overactivation of these systems is a central pathogenic mechanism in several diseases. This review describes the role of complement and coagulation system activation in critical illness, particularly sepsis. The complexities of sepsis reveal significant knowledge gaps that can be compared to a profound abyss, highlighting the urgent need for further investigation and exploration. It is well recognized that the inflammatory network, coagulation, and complement systems are integral mechanisms through which multiple factors contribute to increased susceptibility to infection and may result in a disordered immune response during septic events in patients. Given the overlapping pathogenic mechanisms in sepsis, immunomodulatory therapies currently under development may be particularly beneficial for patients with sepsis who have concurrent infections. Herein, we present recent findings regarding the molecular relationships between the coagulation and complement pathways in the advancement of sepsis, and propose potential intervention targets related to the crosstalk between coagulation and complement, aiming to provide more valuable treatment of sepsis.

Therapeutic Potential of Stem Cell-Derived Extracellular Vesicles in Liver Injury

Liver injury caused by various factors significantly impacts human health. Stem cell transplantation has potential for enhancing liver functionality, but safety concerns such as immune rejection, tumorigenesis, and the formation of emboli in the lungs remain. Recent studies have shown that stem cells primarily exert their effects through the secretion of extracellular vesicles (EVs). EVs have been shown to play crucial roles in reducing inflammation, preventing cell death, and promoting liver cell proliferation. Additionally, they can function as carriers to deliver targeted drugs to the liver, thereby exerting specific physiological effects. EVs possess several advantages, including structural stability, low immunogenicity, minimal tumorigenicity targeting capabilities, and convenient collection. Consequently, EVs have garnered significant attention from researchers and are expected to become alternative therapeutic agents to stem cell therapy. This article provides a comprehensive review of the current research progress in the use of stem cell-derived EVs in the treatment of liver injury.

Novel insights into the role of immunomodulatory extracellular vesicles in the pathogenesis of liver fibrosis

Liver fibrosis, a chronic and long-term disease, can develop into hepatocellular carcinoma (HCC) and ultimately lead to liver failure. Early diagnosis and effective treatment still face significant challenges. Liver inflammation leads to liver fibrosis through continuous activation of hepatic stellate cells (HSCs) and the accumulation of immune cells. Intracellular communication among various immune cells is important for mediating the inflammatory response during fibrogenesis. Extracellular vesicles (EVs), which are lipid bilayer membrane-enclosed particles naturally secreted by cells, make great contributions to cell-cell communication and the transport of bioactive molecules. Nearly all the cells that participate in liver fibrosis release EVs loaded with lipids, proteins, and nucleic acids. EVs from hepatocytes, immune cells and stem cells are involved in mediating the inflammatory microenvironment of liver fibrosis. Recently, an increasing number of extracellular vesicle-based clinical applications have emerged, providing promising cell-free diagnostic and therapeutic tools for liver fibrosis because of their crucial role in immunomodulation during pathogenesis. The advantages of extracellular vesicle-based therapies include stability, biocompatibility, low cytotoxicity, and minimal immunogenicity, which highlight their great potential for drug delivery and specific treatments for liver fibrosis. In this review, we summarize the complex biological functions of EVs in the inflammatory response in the pathogenesis of liver fibrosis and evaluate the potential of EVs in the diagnosis and treatment of liver fibrosis.

Picroside II suppresses chondrocyte pyroptosis through MAPK/NF-κB/NLRP3 signaling pathway alleviates osteoarthritis

BACKGROUND

Picroside II (P-II) is the main bioactive constituent of Picrorhiza Kurroa, a traditional Chinese herb of interest for its proven anti-inflammatory properties. Its beneficial effects have been noted across several physiological systems, including the nervous, circulatory, and digestive, capable of treating a wide range of diseases. Nevertheless, the potential of Picroside II to treat osteoarthritis (OA) and the mechanisms behind its efficacy remain largely unexplored.

AIM

This study aims to evaluate the efficacy of Picroside II in the treatment of osteoarthritis and its potential molecular mechanisms.

METHODS

In vitro, we induced cellular inflammation in chondrocytes with lipopolysaccharide (LPS) and subsequently treated with Picroside II to assess protective effect on chondrocyte. We employed the Cell Counting Kit-8 (CCK-8) assay to assess the impact of Picroside II on cell viability and select the optimal Picroside II concentration for subsequent experiments. We explored the effect of Picroside II on chondrocyte pyroptosis and its underlying molecular mechanisms by qRT-PCR, Western blot (WB) and immunofluorescence. In vivo, we established the destabilization of the medial meniscus surgery to create an OA mouse model. The therapeutic effects of Picroside II were then assessed through Micro-CT scanning, Hematoxylin-eosin (H&E) staining, Safranin O-Fast Green (S&F) staining, immunohistochemistry and immunofluorescence.

RESULTS

In in vitro studies, toluidine blue and CCK-8 results showed that a certain concentration of Picroside II had a restorative effect on the viability of chondrocytes inhibited by LPS. Picroside II notably suppressed the expression levels of caspase-1, IL-18, and IL-1β, which consequently led to the reduction of pyroptosis. Moreover, Picroside II was shown to decrease NLRP3 inflammasome activation, via the MAPK/NF-κB signaling pathway. In vivo studies have shown that Picroside II can effectively reduce subchondral bone destruction and osteophyte formation in the knee joint of mice after DMM surgery.

CONCLUSIONS

Our research suggests that Picroside II can inhibit chondrocyte pyroptosis and ameliorate osteoarthritis progression by modulating the MAPK/NF-κB signaling pathway.

CCT3/ACTN4/TFRC axis protects hepatocellular carcinoma cells from ferroptosis by inhibiting iron endocytosis

Sorafenib is widely used in treating advanced hepatocellular carcinoma (HCC). However, its effectiveness in prolonging patient survival is limited by the development of drug resistance. To systematically investigate the resistance mechanisms of Sorafenib, an integrative analysis combining posttranslational modification (PTM) omics and CRISPR/Cas9 knockout library screening was conducted. This analysis identified ubiquitination at lysine 21 (K21) on chaperonin-containing TCP1 subunit 3 (CCT3) as being associated with Sorafenib resistance. Transcriptomic data from HCC patients treated with Sorafenib revealed that CCT3 expression was lower in responders compared to non-responders. Experimentally, inhibiting the expression of CCT3 sensitized HCC cells to Sorafenib and enhanced Sorafenib-induced ferroptosis. Additionally, CCT3 was found to interact with ACTN4, hindering the recycling of transferrin receptor protein 1 (TFRC) to the cell membrane, thus obstructing iron endocytosis. Mechanistically, the inhibition of ferroptosis by CCT3 depends on the deubiquitination of K6-linked non-degradative ubiquitination at its K21, which occurs upon Sorafenib treatment. Moreover, CCT3 knockdown enhanced the anti-tumor effects of Sorafenib in nude mice. In summary, we have identified a novel function of the chaperone protein. Targeting the CCT3/ACTN4/TFRC axis offers a promising strategy to enhance ferroptosis and overcome Sorafenib resistance in HCC.

Extracellular vesicles from alveolar macrophages harboring phagocytosed methicillin-resistant Staphylococcus aureus induce necroptosis

Methicillin-resistant Staphylococcus aureus (MRSA) infection, a major cause of hospital- and community-acquired pneumonia, still has a high mortality rate. Extracellular vesicles (EVs), as crucial mediators of intercellular communication, have a significant impact on infectious diseases. However, the role of EVs from alveolar macrophages (AMs) in MRSA pneumonia remains unclear. We report that AMs phagocytose MRSA and release more EVs in mice with MRSA pneumonia. EVs from AMs harboring phagocytosed MRSA exhibit significant proinflammatory effects and induce necroptosis by delivering tumor necrosis factor α (TNF-α) and miR-146a-5p. Mechanically, the upregulated miR-146a-5p in these EVs enhances the phosphorylation of RIPK1, RIPK3, and MLKL by targeting TNF receptor-associated factor 6 (TRAF6), thereby promoting TNF-α-induced necroptosis. The combination of a TNF-α antagonist and an miR-146a-5p antagomir effectively improves the outcomes of mice with MRSA pneumonia. Overall, we reveal the pronecrotic effect of EVs from MRSA-infected AMs and provide a promising target for the prevention and treatment of MRSA pneumonia.

The effects of Atractylodes macrocephala extract BZEP self-microemulsion based on gut-liver axis HDL/LPS signaling pathway to ameliorate metabolic dysfunction-associated fatty liver disease in rats

OBJECTIVES

To elucidate the therapeutic effects and mechanisms of Atractylodes macrocephala extract crystallize (BZEP) and BZEP self-microemulsion (BZEPWR) on metabolic dysfunction-associated fatty liver disease (MAFLD) induced by "high sugar, high fat, and excessive alcohol consumption" based on the gut-liver axis HDL/LPS signaling pathway.

METHODS

In this study, BZEP and BZEPWR were obtained via isolation, purification, and microemulsification. Furthermore, an anthropomorphic MAFLD rat model of "high sugar, high fat, and excessive alcohol consumption" was established. The therapeutic effects of BZEPWR and BZEP on the model rats were evaluated in terms of liver function, lipid metabolism (especially HDL-C), serum antioxidant indexes, and liver and intestinal pathophysiology. To determine the lipoproteins in the serum sample, the amplitudes of a plurality of NMR spectra were derived via deconvolution of the composite methyl signal envelope to yield HDL-C subclass concentrations. The changes in intestinal flora were detected via 16 S rRNA gene sequencing. In addition, the gut-liver axis HDL/LPS signaling pathway was validated using immunohistochemistry, immunofluorescence, and western blot.

RESULTS

The findings established that BZEPWR and BZEP improved animal signs, serum levels of liver enzymes (ALT and AST), lipid metabolism (TC, TG, HDL-C, and LDL-C), and antioxidant indexes (GSH, SOD, and ROS). In addition, pathological damage to the liver, colon, and ileum was ameliorated, and the intestinal barrier function of the model rats was restored. At the genus level, BZEPWR and BZEP exerted positive effects on beneficial bacteria, such as Lactobacillus and norank_f__Muribaculaceae, and inhibitory effects on harmful bacteria, such as unclassified_f__Lachnospiraceae and Blautia. Twenty HDL-C subspecies were detected, and their levels were differentially increased in both BZEPWR and BZEP groups, with BZEPWR exhibiting a stronger elevating effect on specific HDL-C subspecies. Also, the gut-liver axis HDL/LPS signaling pathway was studied, which indicated that BZEPWR and BZEP significantly increased the expressions of ABCA1, LXR, occludin, and claudin-1 proteins in the gut and serum levels of HDL-C. Concomitantly, the levels of LPS in the serum and TLR4, Myd88, and NF-κB proteins in the liver were decreased.

CONCLUSION

BZEPWR and BZEP exert restorative and reversal effects on the pathophysiological damage to the gut-liver axis in MAFLD rats, and the therapeutic mechanism may be related to the regulation of the intestinal flora and the HDL/LPS signaling pathway.

YL-109 attenuates sepsis-associated multiple organ injury through inhibiting the ERK/AP-1 axis and pyroptosis by upregulating CHIP

Sepsis is a severe inflammatory disorder that can lead to life-threatening multiple organ injury. Lipopolysaccharide (LPS)-induced inflammation is the leading cause of multiple organ failure in sepsis. This study aimed to explore the effect of a novel agent, 2-(4-hydroxy-3-methoxyphenyl)-benzothiazole (YL-109), on LPS-induced multiple organ injury and the molecular mechanisms underlying these processes. The results showed that YL-109 protected against LPS-induced high mortality, cardiac dysfunction, pulmonary and intestinal injury through inhibiting the proinflammatory response, NLRP3 expression and pyroptosis-associated indicators in mouse tissues. YL-109 suppressed LPS-initiated cytokine release, pyroptosis and pyroptosis-related protein expression in HL-1, IEC-6 and MLE-12 cells, which was consistent with the results of the in vivo experiments. Mechanistically, YL-109 reduces phosphorylated ERK (extracellular signal-regulated kinase) levels and NF-κB activation, which are achieved through upregulating CHIP (carboxy terminus of Hsc70-interacting protein) expression, thereby inhibiting c-Jun and c-Fos activation as well as NLRP3 expression. As an E3 ligase, CHIP overexpression obviously promoted the degradation of phosphorylated ERK and inhibited the expression of NF-κB-mediated NLRP3 in cells stimulated with LPS. The protective effects of YL-109 against cardiac, pulmonary and intestinal damage, inflammation and pyroptosis caused by LPS were eliminated in CHIP knockout mice. Our results not only reveal the protective effect and molecular mechanism of YL-109 against LPS-mediated organs damage but also provide additional insights into the effect of CHIP on negatively regulating pyroptosis and inflammatory pathways.

Human Umbilical Cord Mesenchymal Stem Cells-derived Exosomal lncRNA FAM99B Represses Hepatocellular Carcinoma Cell Malignancy

Human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes (Exo) have been frequently investigated for disease control. This study was designed to explore the effects of hucMSC-Exo carrying lncRNA family with sequence similarity 99-member B (Exo-lncRNA FAM99B) on hepatocellular carcinoma (HCC) cell behaviour. The expression of lncRNA FAM99B in HCC cells was measured by reverse-transcription quantitative polymerase chain reaction. Protein levels of exosomal markers were quantified using western blotting. Flow cytometry analyses were performed to detect surface markers of hucMSCs and to measure the effects of Exo-lncRNA FAM99B on HCC cell cycle progression and cell apoptosis. Nanoparticle tracking analysis was used to measure the particle size of the exosomes. Additionally, cell viability was evaluated using methyl thiazolyl tetrazolium assays, and Transwell assays were performed to measure cell migration and invasion. Xenograft tumor models were established to explore the role of Exo-lncRNA FAM99B in vivo. Experimental results revealed that lncRNA FAM99B was downregulated in HCC cell lines, and low level of FAM99B is associated with poor survival rates in patients with HCC according to bioinformatics analysis. HucMSCs were identified in a good morphology with positively expressed CD105, CD29, and CD44 as well as negatively expressed CD31, CD14, and HLA-DR. High protein levels of exosomal markers (Alix, CD63 and TSG101) identified the existence of HucMSC-Exo. Importantly, the hucMSCs-Exo could enter HCC cells and exerted a suppressive effect on malignant cell activities. Moreover, overexpression of Exo-lncRNA FAM99B enhanced cell cycle arrest and cell apoptosis while suppressing cell viability, migration, and invasion in HCC. Exo-siRNA-FAM99B exerted the opposite effects on HCC cell process. In vivo experiments verified that Exo-lncRNA FAM99B inhibited tumorigenesis in HCC. In summary, lncRNA FAM99B derived from hucMSC-Exo inhibited malignant cellular phenotypes and tumorigenesis in HCC, which might provide a novel therapeutic strategy for HCC treatment.

Unveiling the Role of Exosomes in the Pathophysiology of Sepsis: Insights into Organ Dysfunction and Potential Biomarkers

Extracellular vesicles (EVs) are tools for intercellular communication, mediating molecular transport processes. Emerging studies have revealed that EVs are significantly involved in immune processes, including sepsis. Sepsis, a dysregulated immune response to infection, triggers systemic inflammation and multi-organ dysfunction, posing a life-threatening condition. Although extensive research has been conducted on animals, the complex inflammatory mechanisms that cause sepsis-induced organ failure in humans are still not fully understood. Recent studies have focused on secreted exosomes, which are small extracellular vesicles from various body cells, and have shed light on their involvement in the pathophysiology of sepsis. During sepsis, exosomes undergo changes in content, concentration, and function, which significantly affect the metabolism of endothelia, cardiovascular functions, and coagulation. Investigating the role of exosome content in the pathogenesis of sepsis shows promise for understanding the molecular basis of human sepsis. This review explores the contributions of activated immune cells and diverse body cells' secreted exosomes to vital organ dysfunction in sepsis, providing insights into potential molecular biomarkers for predicting organ failure in septic shock.

Regulation of regulated cell death by extracellular vesicles in acute kidney injury and chronic kidney disease

The imbalance between proliferation and death of kidney resident cells is a crucial factor in the development of acute or chronic renal dysfunction. Acute kidney injury (AKI) is often associated with the rapid loss of tubular epithelial cells (TECs). Sustained injury leads to the loss of glomerular endothelial cells (GECs) and podocytes, which is a key mechanism in the pathogenesis of glomerular diseases. This irreversible damage resulting from progressive cell loss eventually leads to deterioration of renal function characterized by glomerular compensatory hypertrophy, tubular degeneration, and renal fibrosis. Regulated cell death (RCD), which involves a cascade of gene expression events with tight structures, plays a certain role in regulating kidney health by determining the fate of kidney resident cells. Under pathological conditions, cells in the nephron have been demonstrated to constitutively release extracellular vesicles (EVs) which act as messengers that specifically interact with recipient cells to regulate their cell death process. For therapeutic intervention, exogenous EVs have exhibited great potential for the prevention and treatment of kidney disease by modulating RCD, with enhanced effects through engineering modification. Based on the functional role of EVs, this review comprehensively explores the regulation of RCD by EVs in AKI and chronic kidney disease (CKD), with emphasis on pathogenesis and therapeutic intervention.

Lipopolysaccharide delivery systems in innate immunity

Lipopolysaccharide (LPS), a key component of the outer membrane in Gram-negative bacteria (GNB), is widely recognized for its crucial role in mammalian innate immunity and its link to mortality in intensive care units. While its recognition via the Toll-like receptor (TLR)-4 receptor on cell membranes is well established, the activation of the cytosolic receptor caspase-11 by LPS is now known to lead to inflammasome activation and subsequent induction of pyroptosis. Nevertheless, a fundamental question persists regarding the mechanism by which LPS enters host cells. Recent investigations have identified at least four primary pathways that can facilitate this process: bacterial outer membrane vesicles (OMVs); the spike (S) protein of SARS-CoV-2; host-secreted proteins; and host extracellular vesicles (EVs). These delivery systems provide new avenues for therapeutic interventions against sepsis and infectious diseases.

Interorgan communication in neurogenic heterotopic ossification: the role of brain-derived extracellular vesicles

Brain-derived extracellular vesicles participate in interorgan communication after traumatic brain injury by transporting pathogens to initiate secondary injury. Inflammasome-related proteins encapsulated in brain-derived extracellular vesicles can cross the blood‒brain barrier to reach distal tissues. These proteins initiate inflammatory dysfunction, such as neurogenic heterotopic ossification. This recurrent condition is highly debilitating to patients because of its relatively unknown pathogenesis and the lack of effective prophylactic intervention strategies. Accordingly, a rat model of neurogenic heterotopic ossification induced by combined traumatic brain injury and achillotenotomy was developed to address these two issues. Histological examination of the injured tendon revealed the coexistence of ectopic calcification and fibroblast pyroptosis. The relationships among brain-derived extracellular vesicles, fibroblast pyroptosis and ectopic calcification were further investigated in vitro and in vivo. Intravenous injection of the pyroptosis inhibitor Ac-YVAD-cmk reversed the development of neurogenic heterotopic ossification in vivo. The present work highlights the role of brain-derived extracellular vesicles in the pathogenesis of neurogenic heterotopic ossification and offers a potential strategy for preventing neurogenic heterotopic ossification after traumatic brain injury. Brain-derived extracellular vesicles (BEVs) are released after traumatic brain injury. These BEVs contain pathogens and participate in interorgan communication to initiate secondary injury in distal tissues. After achillotenotomy, the phagocytosis of BEVs by fibroblasts induces pyroptosis, which is a highly inflammatory form of lytic programmed cell death, in the injured tendon. Fibroblast pyroptosis leads to an increase in calcium and phosphorus concentrations and creates a microenvironment that promotes osteogenesis. Intravenous injection of the pyroptosis inhibitor Ac-YVAD-cmk suppressed fibroblast pyroptosis and effectively prevented the onset of heterotopic ossification after neuronal injury. The use of a pyroptosis inhibitor represents a potential strategy for the treatment of neurogenic heterotopic ossification.

Extracellular histones exacerbate heat stroke-induced liver injury by triggering hepatocyte pyroptosis and liver injury via the TLR9-NLRP3 pathway

BACKGROUND

Severe heat stroke is often complicated by multiple organ failure, including liver injury. Recent evidence indicates that the underlying mechanism constitutes sterile inflammation triggered by cell damage, in which hepatocyte NOD-like receptor family pyrin domain-containing 3 inflammasome activation and pyroptosis play key roles. As extracellular histones act as damage-associated molecular patterns and mediate tissue toxicity and inflammation, we aimed to investigate whether extracellular histones contribute to inducing hepatocyte pyroptosis following heat stroke, promoting the development of liver inflammation and injury, and elucidate the potential underlying mechanisms.

METHODS

Exogenous histones were administered to AML-12 murine hepatocytes or male aged 8-12 week mice following hyperthermic treatment (at 39 °C in a chamber with 60 % relative humidity). Prior to heat exposure, endogenous histones were neutralized using neutralizing antibodies, inflammasomes were inhibited by RNA silencing, and Toll-like receptor 9 was modulated using a pharmacological agonist or antagonist. Inflammasome assembly, caspase-1 activation, histological changes, and liver enzyme levels were measured. Statistical comparison of more than two groups was performed using one-way ANOVA with Tukey's post-hoc testing. The correlations were analyzed using Pearson's correlation test. All experiments were repeated thrice. A p-value < 0.05 was considered significant.

RESULTS

Heat stroke induced histone release into the extracellular space at levels correlating with liver injury. Moreover, extracellular histones augmented heat stroke-induced liver injury both in vitro and in vivo in a dose- and time-dependent manner, whereas neutralizing histones conferred protection following heat stroke. Histones mediated NOD-like receptor family pyrin domain-containing 3 inflammasome activation through the Toll-like receptor 9 signaling pathway, which resulted in hepatocyte pyroptosis and liver inflammation.

CONCLUSIONS

Our findings show that histones are critical mediators of hepatocyte pyroptosis that aggravate liver injury in a heat stroke setting. Therefore, we suggest extracellular histones as potential therapeutic targets to limit heat stroke-induced cell death and liver injury.

Nanocurcumin attenuates pyroptosis and inflammation through inhibiting NF-κB/GSDMD signal in high altitude-associated acute liver injury

Exposure to a hypobaric hypoxic environment at high altitudes can lead to liver injury, and mounting evidence indicates that pyroptosis and inflammation play important roles in liver injury. Curcumin (Cur) can inhibit pyroptosis and inflammation. Therefore, our purpose here was to clarify the mechanism underlying the protective effect of nanocurcumin (Ncur) and Cur in a rat model of high altitude-associated acute liver injury. Eighty healthy rats were selected and exposed to different altitudes (6000 or 7000 m) for 0, 24, 48, or 72 h. Fifty normal healthy rats were divided into normal control, high-altitude control, salidroside (40 mg/kg [Sal-40]), Cur (200 mg/kg [Cur-200]), and Ncur (25 mg/kg [Ncur-25]) groups and exposed to a high-altitude hypobaric hypoxic environment (48 h, 7000 m). Serum-liver enzyme activities (alanine transaminase, aspartate transaminase, and lactate dehydrogenase were detected and histopathology of liver injury was evaluated by hematoxylin and eosin staining, and inflammatory factors were detected in liver tissues by enzyme-linked immunosorbent assays. Pyroptosis-associated proteins (gasdermin D, gasdermin D N-terminal [GSDMD-N], pro-Caspase-1, and cleaved-Caspase-1 [cleaved-Casp1]) and inflammation-associated proteins (nuclear factor-κB [NF-κB], phospho-NF-κB [P-NF-κB], and high-mobility group protein B1 [HMGB1]) levels were analyzed by immunoblotting. Ncur and Cur inhibited increased serum-liver enzyme activities, alleviated liver injury in rats caused by high-altitude hypobaric hypoxic exposure, and downregulated inflammatory factors, including tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-18, in rat liver tissues. The level of P-NF-κB, GSDMD-N, cleaved-Casp1, and HMGB1 in rat liver tissues increased significantly after high-altitude exposure. Ncur and Cur downregulated P-NF-κB, GSDMD-N, cleaved-Casp-1, and HMGB1. Ncur and Cur may inhibit inflammatory responses and pyroptosis in a rat model of high altitude-associated acute liver injury.

Vesicular HMGB1 release from neurons stressed with spreading depolarization enables confined inflammatory signaling to astrocytes

The role of high mobility group box 1 (HMGB1) in inflammation is well characterized in the immune system and in response to tissue injury. More recently, HMGB1 was also shown to initiate an "inflammatory signaling cascade" in the brain parenchyma after a mild and brief disturbance, such as cortical spreading depolarization (CSD), leading to headache. Despite substantial evidence implying a role for inflammatory signaling in prevalent neuropsychiatric disorders such as migraine and depression, how HMGB1 is released from healthy neurons and how inflammatory signaling is initiated in the absence of apparent cell injury are not well characterized. We triggered a single cortical spreading depolarization by optogenetic stimulation or pinprick in naïve Swiss albino or transgenic Thy1-ChR2-YFP and hGFAP-GFP adult mice. We evaluated HMGB1 release in brain tissue sections prepared from these mice by immunofluorescent labeling and immunoelectron microscopy. EzColocalization and Costes thresholding algorithms were used to assess the colocalization of small extracellular vesicles (sEVs) carrying HMGB1 with astrocyte or microglia processes. sEVs were also isolated from the brain after CSD, and neuron-derived sEVs were captured by CD171 (L1CAM). sEVs were characterized with flow cytometry, scanning electron microscopy, nanoparticle tracking analysis, and Western blotting. We found that HMGB1 is released mainly within sEVs from the soma of stressed neurons, which are taken up by surrounding astrocyte processes. This creates conditions for selective communication between neurons and astrocytes bypassing microglia, as evidenced by activation of the proinflammatory transcription factor NF-ĸB p65 in astrocytes but not in microglia. Transmission immunoelectron microscopy data illustrated that HMGB1 was incorporated into sEVs through endosomal mechanisms. In conclusion, proinflammatory mediators released within sEVs can induce cell-specific inflammatory signaling in the brain without activating transmembrane receptors on other cells and causing overt inflammation.

The pathogenesis and potential therapeutic targets in sepsis

Sepsis is defined as "a life-threatening organ dysfunction caused by dysregulated host systemic inflammatory and immune response to infection." At present, sepsis continues to pose a grave healthcare concern worldwide. Despite the use of supportive measures in treating traditional sepsis, such as intravenous fluids, vasoactive substances, and oxygen plus antibiotics to eradicate harmful pathogens, there is an ongoing increase in both the morbidity and mortality associated with sepsis during clinical interventions. Therefore, it is urgent to design specific pharmacologic agents for the treatment of sepsis and convert them into a novel targeted treatment strategy. Herein, we provide an overview of the molecular mechanisms that may be involved in sepsis, such as the inflammatory response, immune dysfunction, complement deactivation, mitochondrial damage, and endoplasmic reticulum stress. Additionally, we highlight important targets involved in sepsis-related regulatory mechanisms, including GSDMD, HMGB1, STING, and SQSTM1, among others. We summarize the latest advancements in potential therapeutic drugs that specifically target these signaling pathways and paramount targets, covering both preclinical studies and clinical trials. In addition, this review provides a detailed description of the crosstalk and function between signaling pathways and vital targets, which provides more opportunities for the clinical development of new treatments for sepsis.

TRAF6 triggers Mycobacterium-infected host autophagy through Rab7 ubiquitination

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an E3 ubiquitin ligase that is extensively involved in the autophagy process by interacting with diverse autophagy initiation and autophagosome maturation molecules. However, whether TRAF6 interacts with lysosomal proteins to regulate Mycobacterium-induced autophagy has not been completely characterized. Herein, the present study showed that TRAF6 interacted with lysosomal key proteins Rab7 through RING domain which caused Rab7 ubiquitination and subsequently ubiquitinated Rab7 binds to STX17 (syntaxin 17, a SNARE protein that is essential for mature autophagosome), and thus promoted the fusion of autophagosomes and lysosomes. Furthermore, TRAF6 enhanced the initiation and formation of autophagosomes in Mycobacterium-induced autophagy in both BMDMs and RAW264.7 cells, as evidenced by autophagic flux, colocalization of LC3 and BCG, autophagy rates, and autophagy-associated protein expression. Noteworthy to mention, TRAF6 deficiency exacerbated lung injury and promoted BCG survival. Taken together, these results identify novel molecular and cellular mechanisms by which TRAF6 positively regulates Mycobacterium-induced autophagy.

Angelica acutiloba Kitagawa flower induces A549 cell pyroptosis via the NF-κB/NLRP3 pathway for anti-lung cancer effects

Angelica acutiloba Kitagawa, a traditional medicinal herb of the Umbelliferae family, has been demonstrated to have anticancer activity. In this study, we investigated the anti-lung cancer effects of two compounds extracted from A. acutiloba flowers: kaempferol-3-O-α-L-(4″-E-p-coumaroyl)-rhamnoside (KAE) and platanoside (PLA). MTT, cell colony formation, and cell migration (scratch) assays revealed that both KAE (100 μM) and PLA (50 μM and 100 μM) inhibited the viability, proliferation, and migration of A549 cells. Dichlorodihydrofluorescein diacetate assays showed that KAE and PLA also induced the generation of reactive oxygen species in A549 cells. Morphologically, A549 cells swelled and grew larger under treatment with KAE and PLA, with the most significant changes at 100 μM PLA. Fluorescence staining and measurement of lactate dehydrogenase release showed that the cells underwent pyroptosis with concomitant upregulation of interleukin (IL)-1β and IL-18. Furthermore, both KAE and PLA induced upregulation of NF-κB, PARP, NLRP3, ASC, cleaved-caspase-1, and GSDMD expression in A549 cells. Subsequent investigations unveiled that these compounds interact with NLRP3, augment NLRP3's binding affinity with ASC, and stimulate the assembly of the inflammasome, thereby inducing pyroptosis. In conclusion, KAE and PLA, two active components of A. acutiloba flower extract, had significant anti-lung cancer activities exerted through regulation of proteins related to the NLRP3 inflammasome pathway.

Extracellular Vesicles in Sepsis: Pathogenic Roles, Organ Damage, and Therapeutic Implications

Despite significant advances in anti-infective treatment and organ function support technology in recent years, the mortality rate of sepsis remains high. In addition to the high costs of sepsis treatment, the increasing consumption of medical resources also aggravates economic pressure and social burden. Extracellular vesicles (EVs) are membrane vesicles released from different types of activated or apoptotic cells to mediate intercellular communication, which can be detected in both human and animal body fluids. A growing body of researches suggest that EVs play an important role in the pathogenesis of sepsis. In this review, we summarize the predominant roles of EVs in various pathological processes during sepsis and its related organ dysfunction.

HMGB1 induces macrophage pyroptosis in chronic endometritis

BACKGROUND

Chronic endometritis (CE) reflects the local imbalance in the endometrial immune microenvironment after inflammation. High mobility group box 1 (HMGB1) is highly involved in both immunity and inflammation. In this study, we aimed to explore the roles of HMGB1 in the endometrium of patients with CE.

METHODS

Endometrium and uterine fluid HMGB1 were tested in a cohort of infertile patients with or without CE. Expression levels of the pyroptosis marker, gasdermin D (GSDMD)-N-terminal (NT), in the human endometrium of patients with CE and controls were determined. Next, the role of HMGB1 as a driver of macrophage pyroptosis was investigated using human THP-1 cells in vitro and a CE mouse model in vivo.

RESULTS

High expression levels of HMGB1 in biopsied endometrial tissue and uterine fluid were confirmed in a cohort of patients with CE. Positive correlation between the number of CD138+ cells and HMGB1 mRNA expression level were detected (rs = 0.592, P < 0.001). Meanwhile, we found that GSDMD-NT expression was significantly increased in the CE endometrium at both the transcriptional and translational levels. Moreover, co-localization of GSDMD-NT and macrophages was confirmed via the double immunostaining of GSDMD-NT and CD68. In vitro experiments revealed that macrophage pyroptosis was induced by HMGB1 in human THP-1-derived macrophages. Treatment with glycyrrhizic acid, an inhibitor of HMGB1, significantly suppressed endometrial pyroptosis and inflammation in the CE mouse model.

CONCLUSIONS

HMGB1 effectively induced macrophage pyroptosis in the human endometrium, suggesting that its inhibition may serve as a novel treatment option for CE.

Castanopsis sieboldii Extract Alleviates Acute Liver Injury by Antagonizing Inflammasome-Mediated Pyroptosis

Castanopsis sieboldii (CS), a subtropical species, was reported to have antioxidant and antibacterial effects. However, the anti-inflammatory effects of CS have not been studied. This study aimed to investigate whether the 70% ethanol extract of the CS leaf (CSL3) inhibited lipopolysaccharide (LPS)-induced inflammatory responses and LPS and ATP-induced pyroptosis in macrophages. CSL3 treatment inhibited NO release and iNOS expression in LPS-stimulated cells. CSL3 antagonized NF-κB and AP-1 activation, which was due to MAPK (p38, ERK, and JNK) inhibition. CSL3 successfully decreased NLRP3 inflammasome activation and increased IL-1β expression. CSL3 treatment diminished LPS and ATP-induced pore formation in GSDMD. The in vivo effect of CSL3 on acute liver injury was evaluated in a CCl4-treated mouse model. CCl4 treatment increased the activity of serum alanine aminotransferase and aspartate aminotransferase, which decreased by CSL3. In addition, CCl4-induced an increase in TNF-α, and IL-6 levels decreased by CSL3 treatment. Furthermore, we verified that the CCl4-induced inflammasome and pyroptosis-related gene expression in liver tissue and release of IL-1β into serum were suppressed by CSL3 treatment. Our results suggest that CSL3 protects against acute liver injury by inhibiting inflammasome formation and pyroptosis.

Context-specific regulation of extracellular vesicle biogenesis and cargo selection

To coordinate, adapt and respond to biological signals, cells convey specific messages to other cells. An important aspect of cell-cell communication involves secretion of molecules into the extracellular space. How these molecules are selected for secretion has been a fundamental question in the membrane trafficking field for decades. Recently, extracellular vesicles (EVs) have been recognized as key players in intercellular communication, carrying not only membrane proteins and lipids but also RNAs, cytosolic proteins and other signalling molecules to recipient cells. To communicate the right message, it is essential to sort cargoes into EVs in a regulated and context-specific manner. In recent years, a wealth of lipidomic, proteomic and RNA sequencing studies have revealed that EV cargo composition differs depending upon the donor cell type, metabolic cues and disease states. Analyses of distinct cargo 'fingerprints' have uncovered mechanistic linkages between the activation of specific molecular pathways and cargo sorting. In addition, cell biology studies are beginning to reveal novel biogenesis mechanisms regulated by cellular context. Here, we review context-specific mechanisms of EV biogenesis and cargo sorting, focusing on how cell signalling and cell state influence which cellular components are ultimately targeted to EVs.

Oxaliplatin related lncRNAs prognostic models predict the prognosis of patients given oxaliplatin-based chemotherapy

BACKGROUND

Oxaliplatin-based chemotherapy is the first-line treatment for colorectal cancer (CRC). Long noncoding RNAs (lncRNAs) have been implicated in chemotherapy sensitivity. This study aimed to identify lncRNAs related to oxaliplatin sensitivity and predict the prognosis of CRC patients underwent oxaliplatin-based chemotherapy.

METHODS

Data from the Genomics of Drug Sensitivity in Cancer (GDSC) was used to screen for lncRNAs related to oxaliplatin sensitivity. Four machine learning algorithms (LASSO, Decision tree, Random-forest, and support vector machine) were applied to identify the key lncRNAs. A predictive model for oxaliplatin sensitivity and a prognostic model based on key lncRNAs were established. The published datasets, and cell experiments were used to verify the predictive value.

RESULTS

A total of 805 tumor cell lines from GDSC were divided into oxaliplatin sensitive (top 1/3) and resistant (bottom 1/3) groups based on their IC50 values, and 113 lncRNAs, which were differentially expressed between the two groups, were selected and incorporated into four machine learning algorithms, and seven key lncRNAs were identified. The predictive model exhibited good predictions for oxaliplatin sensitivity. The prognostic model exhibited high performance in patients with CRC who underwent oxaliplatin-based chemotherapies. Four lncRNAs, including C20orf197, UCA1, MIR17HG, and MIR22HG, displayed consistent responses to oxaliplatin treatment in the validation analysis.

CONCLUSION

Certain lncRNAs were associated with oxaliplatin sensitivity and predicted the response to oxaliplatin treatment. The prognostic models established based on the key lncRNAs could predict the prognosis of patients given oxaliplatin-based chemotherapy.

Human Umbilical Cord Mesenchymal Stem Cells Protect against Renal Ischemia-Reperfusion Injury by Secreting Extracellular Vesicles Loaded with miR-148b-3p That Target Pyruvate Dehydrogenase Kinase 4 to Inhibit Endoplasmic Reticulum Stress at the Reperfusion Stages

Renal ischemia-reperfusion (I/R) injury is a leading cause of acute kidney injury (AKI), with high mortality. Recent studies have reported that human umbilical cord mesenchymal stem cells (HucMSCs) play an important role in repairing organ and tissue injuries because of their unique characteristics. However, the potential of HucMSC extracellular vesicles (HucMSC-EVs) to promote the repair of renal tubular cells remains to be explored. This study found that HucMSC-EVs derived from HucMSCs played a protective role and were associated with kidney I/R injury. We found that miR-148b-3p in HucMSC-EVs had a protective effect against kidney I/R injury. HK-2 cells overexpressing miR-148b-3p were protected against I/R injury by inhibiting apoptosis. Next, the target mRNA of miR-148b-3p was predicted online, and the target mRNA, pyruvate dehydrogenase kinase 4 (PDK4), was identified and verified using dual luciferase. We discovered that I/R injury significantly increased endoplasmic reticulum (ER) stress, whereas siR-PDK4 inhibited these effects and protected against I/R injury. Interestingly, after administrating HucMSC-EVs to HK-2 cells, PDK4 expression and ER stress induced by I/R injury were significantly inhibited. HK-2 ingested miR-148b-3p from HucMSC-EVs, and its ER induced by I/R injury was significantly deregulated. This study suggests that HucMSC-EVs protect kidneys from I/R injury during the early I/R stage. These results suggest a new mechanism for HucMSC-EVs in treating AKI and provide a new treatment strategy for I/R injury.

Circulating extracellular vesicles from patients with traumatic brain injury induce cerebrovascular endothelial dysfunction

Endothelial dysfunction is a key proponent of pathophysiological process of traumatic brain injury (TBI). We previously demonstrated that extracellular vesicles (EVs) released from injured brains led to endothelial barrier disruption and vascular leakage. However, the molecular mechanisms of this EV-induced endothelial dysfunction (endotheliopathy) remain unclear. Here, we enriched plasma EVs from TBI patients (TEVs), and detected high mobility group box 1 (HMGB1) exposure to 50.33 ± 10.17% of TEVs and the number of HMGB1⁺TEVs correlated with injury severity. We then investigated for the first time the impact of TEVs on endothelial function using adoptive transfer models. We found that TEVs induced dysfunction of cultured human umbilical vein endothelial cells and mediated endothelial dysfunction in both normal and TBI mice, which were propagated through the HMGB1-activated receptor for advanced glycation end products (RAGE)/Cathepsin B signaling, and the resultant NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation and canonical caspase-1/gasdermin D (GSDMD)-dependent pyroptosis. Finally, von Willebrand factor (VWF) was detected on the surface of 77.01 ± 7.51% of HMGB1⁺TEVs. The TEV-mediated endotheliopathy was reversed by a polyclonal VWF antibody, indicating that VWF might serve a coupling factor that tethered TEVs to ECs, thus facilitating HMGB1-induced endotheliopathy. These results suggest that circulating EVs isolated from patients with TBI alone are sufficient to induce endothelial dysfunction and contribute to secondary brain injury that are dependent on immunologically active HMGB1 exposed on their surface. This finding provided new insight for the development of potential therapeutic targets and diagnostic biomarkers for TBI.

Recuperative herbal formula Jing Si maintains vasculature permeability balance, regulates inflammation and assuages concomitants of "Long-Covid"

Coronavirus disease 2019 (COVID-19) is a worldwide health threat that has long-term effects on the patients and there is currently no efficient cure prescribed for the treatment and the prolonging effects. Traditional Chinese medicines (TCMs) have been reported to exert therapeutic effect against COVID-19. In this study, the therapeutic effects of Jing Si herbal tea (JSHT) against COVID-19 infection and associated long-term effects were evaluated in different in vitro and in vivo models. The anti-inflammatory effects of JSHT were studied in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and in Omicron pseudotyped virus-induced acute lung injury model. The effect of JSHT on cellular stress was determined in HK-2 proximal tubular cells and H9c2 cardiomyoblasts. The therapeutic benefits of JSHT on anhedonia and depression symptoms associated with long COVID were evaluated in mice models for unpredictable chronic mild stress (UCMS). JSHT inhibited the NF-ƙB activities, and significantly reduced LPS-induced expression of TNFα, COX-2, NLRP3 inflammasome, and HMGB1. JSHT was also found to significantly suppress the production of NO by reducing iNOS expression in LPS-stimulated RAW 264.7 cells. Further, the protective effects of JSHT on lung tissue were confirmed based on mitigation of lung injury, repression in TMRRSS2 and HMGB-1 expression and reduction of cytokine storm in the Omicron pseudotyped virus-induced acute lung injury model. JSHT treatment in UCMS models also relieved chronic stress and combated depression symptoms. The results therefore show that JSHT attenuates the cytokine storm by repressing NF-κB cascades and provides the protective functions against symptoms associated with long COVID-19 infection.

Association of HMGB1 levels in synovial fluid with the severity of temporomandibular joint osteoarthritis

BACKGROUND

HMGB1 usually serves as a damage-associated molecular pattern (DAMP) molecule (also known as alarmin) that regulates the inflammatory and immune responses via different receptors or direct uptake. Numerous studies have reported the association between HMGB1 and inflammatory diseases; however, its role in temporomandibular joint (TMJ) osteoarthritis (OA) has not been elucidated. In this retrospective study, we aimed to investigate HMGB1 levels in the synovial fluid (SF) in patients with TMJOA and TMID, their correlation with TMJOA and TMID severity, and the therapeutic effect of sodium hyaluronate (hyaluronic acid, HA) on TMJOA.

METHODS

SF samples were analyzed for 30 patients with TMJ internal derangement (TMJID) and TMJOA, along with visual analog scale (VAS) scores, radiographic stages, and mandibular functional limitations. The SF levels of HMGB1, IL-1β, IL-18, PGE2, RAGE, TLR4, and iNOS were determined via an enzyme-linked immunosorbent assay. To evaluate the therapeutic effects of HA, pre-treatment and post-treatment clinical symptoms were also compared in patients of the TMJOA group who had received an intra-articular injection of HA.

RESULTS

VAS and Jaw Functional Limitation Scale (JFLS) scores were significantly higher in the TMJOA group than in the TMNID group, as were SF levels of HMGB1, TLR4, IL-1β, IL-18, PGE2, and iNOS. The synovial HMGB1 level was positively correlated with the VAS score (r = 0.5512, p = 0.0016) and mandibular functional limitations (r = 0.4684, p = 0.0054). The cut-off value for the HMGB1 level as a diagnostic biomarker was 986.8 pg/ml. The SF level of HMGB1 yielded an area under the curve value (AUC) of 0.8344 for predicting TMJOA. HA alleviated TMJ disorders by significantly reducing the VAS score and improving the maximum extent of mouth opening in both the TMJID and TMJOA groups (p < 0.05). Moreover, patients in both the TMJID and TMJOA groups exhibited significant improvement in the JFLS score following HA treatment.

CONCLUSIONS

Our results indicate that HMGB1 is a potential marker for predicting the severity of TMJOA. Intra-articular HA injection exerts a positive therapeutic effect on TMJOA; however, further investigations are warranted to validate its therapeutic effect in the late phase of visco-supplementation treatment.

THE ROLES OF EXTRACELLULAR VESICLES IN SEPSIS AND SYSTEMIC INFLAMMATORY RESPONSE SYNDROME

ABSTRACT

Sepsis is a life-threatening organ dysfunction, caused by dysregulation of the host response to infection. To understand the underlying mechanisms of sepsis, the vast spectrum of extracellular vesicles (EVs) is gaining importance in this research field. A connection between EVs and sepsis was shown in 1998 in an endotoxemia pig model. Since then, the number of studies describing EVs as markers and mediators of sepsis increased steadily. Extracellular vesicles in sepsis could be friends and foes at the same time depending on their origin and cargo. On the one hand, transfer of EVs or outer membrane vesicles can induce sepsis or systemic inflammatory response syndrome with comparable efficiency as well-established methods, such as cecal ligation puncture or lipopolysaccharide injection. On the other hand, EVs could provide certain therapeutic effects, mediated via reduction of reactive oxygen species, inflammatory cytokines and chemokines, influence on macrophage polarization and apoptosis, as well as increase of anti-inflammatory cytokines. Moreover, EVs could be helpful in the diagnosis of sepsis. Extracellular vesicles of different cellular origin, such as leucocytes, macrophages, platelets, and granulocytes, have been suggested as potential sepsis biomarkers. They ensure the diagnosis of sepsis earlier than classical clinical inflammation markers, such as C-reactive protein, leucocytes, or IL-6. This review summarizes the three roles of EVs in sepsis-mediator/inducer, biomarker, and therapeutic tool.

Recent Advances in Understanding of Pathogenesis of Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is one of the major diseases arising from chronic alcohol consumption and is one of the most common causes of liver-related morbidity and mortality. ALD includes asymptomatic liver steatosis, fibrosis, cirrhosis, and alcohol-associated hepatitis and its complications. The progression of ALD involves complex cell-cell and organ-organ interactions. We focus on the impact of alcohol on dysregulation of homeostatic mechanisms and regulation of injury and repair in the liver. In particular, we discuss recent advances in understanding the disruption of balance between programmed cell death and prosurvival pathways, such as autophagy and membrane trafficking, in the pathogenesis of ALD. We also summarize current understanding of innate immune responses, liver sinusoidal endothelial cell dysfunction and hepatic stellate cell activation, and gut-liver and adipose-liver cross talk in response to ethanol. In addition,we describe the current potential therapeutic targets and clinical trials aimed at alleviating hepatocyte injury, reducing inflammatory responses, and targeting gut microbiota, for the treatment of ALD.

Role of Small Extracellular Vesicles in Liver Diseases: Pathogenesis, Diagnosis, and Treatment

Extracellular vesicles (EVs) are vesicular bodies that bud off from the cell membrane or are secreted virtually by all cell types. Small EVs (sEVs or exosomes) are key mediators of cell-cell communication by delivering their cargo, including proteins, lipids, or RNAs, to the recipient cells where they induce changes in signaling pathways and phenotypic properties. Tangible findings have revealed the pivotal involvement of sEVs in the pathogenesis of various diseases. On the bright side, they are rich sources of biomarkers for diagnosis, prognosis, treatment response, and disease monitoring. sEVs have high stability, biocompatibility, targetability, low toxicity, and are immunogenic in nature. Their intrinsic properties make sEVs an ideal delivery vehicle to be loaded with cargo for therapeutic interventions. Liver diseases are a major global health problem. This review aims to focus on the roles and mechanisms of sEVs in the pathogenesis of liver diseases, liver injury, liver failure, and liver cancer. sEVs are released not only by hepatocytes but also by stromal and immune cells in the microenvironment. Early detection of liver disease determines the chance for curative treatment and high survival of patients. This review focuses on the potential of circulating sEV cargo as specific and sensitive noninvasive biomarkers for the early detection and prognosis of liver diseases. In addition, the therapeutic use of sEVs derived from various cell types is discussed. Although sEVs hold promise for clinical applications, there are still challenges to be overcome by further research to bring utilization of sEVs into clinical practice.

Danger signals released during cold ischemia storage activate NLRP3 inflammasome in myeloid cells and influence early allograft function in liver transplantation

BACKGROUND

Innate immunity plays a fundamental role in solid organ transplantation. Myeloid cells can sense danger signals or DAMPs released after tissue or cell damage, such as during ischemia processes. This study aimed to identify DAMPs released during cold ischemia storage of human liver and analyze their ability to activate the inflammasome in myeloid cells and the possible implications in terms of short-term outcomes of liver transplantation.

METHODS

79 samples of organ preservation solution (OPS) from 79 deceased donors were collected after cold static storage. We used different analytical methods to measure DAMPs in these end-ischemic OPS (eiOPS) samples. We also used eiOPS in the human macrophage THP-1 cell line and primary monocyte cultures to study inflammasome activation.

FINDINGS

Different DAMPs were identified in eiOPS, several of which induced both priming and activation of the NLRP3 inflammasome in human myeloid cells. Cold ischemia time and donation after circulatory death negatively influenced the DAMP signature. Moreover, the presence of oligomeric inflammasomes and interleukin-18 in eiOPS correlated with early allograft dysfunction in liver transplant patients.

INTERPRETATION

DAMPs released during cold ischemia storage prime and activate the NLRP3 inflammasome in liver macrophages after transplantation, inducing a pro-inflammatory environment that will complicate the outcome of the graft. The use of pharmacological blockers targeting DAMPs or the NLRP3 inflammasome in liver ischemia during static cold storage or through extracorporeal organ support could be a suitable strategy to increase the success of liver transplantation.

FUNDING

Fundación Mutua Madrileña and Instituto de Salud Carlos III, Madrid, Spain.

Extracellular vesicles participate in the pathogenesis of sepsis

Sepsis is one of the leading causes of mortality worldwide and is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. The early diagnosis and effective treatment of sepsis still face challenges due to its rapid progression, dynamic changes, and strong heterogeneity among different individuals. To develop novel strategies to control sepsis, a better understanding of the complex mechanisms of sepsis is vital. Extracellular vesicles (EVs) are membrane vesicles released from cells through different mechanisms. In the disease state, the number of EVs produced by activated or apoptotic cells and the cargoes they carry were altered. They regulated the function of local or distant host cells in autocrine or paracrine ways. Current studies have found that EVs are involved in the occurrence and development of sepsis through multiple pathways. In this review, we focus on changes in the cargoes of EVs in sepsis, the regulatory roles of EVs derived from host cells and bacteria, and how EVs are involved in multiple pathological processes and organ dysfunction in sepsis. Overall, EVs have great application prospects in sepsis, such as early diagnosis of sepsis, dynamic monitoring of disease, precise therapeutic targets, and prevention of sepsis as a vaccine platform.

DAMPs Released from Proinflammatory Macrophages Induce Inflammation in Cardiomyocytes via Activation of TLR4 and TNFR

Cardiac dysfunction is a life-threatening complication in sepsis. Upon infection and cardiac stress, the cardiac macrophage population expands. Recruited macrophages exhibit a predominantly proinflammatory phenotype and release danger-associated molecular patterns (DAMPs) that contribute to cardiac dysfunction. However, the underlying pathomechanisms are highly complex and not fully understood. Here, we utilized an indirect macrophage-cardiomyocyte co-culture model to study the effects of proinflammatory macrophages on the activation of different cardiac receptors (TLR3, TLR4, and TNFR) and their role in cardiac inflammation and caspase-3/7 activation. The stimulation of cardiomyocytes with conditioned medium of LPS-stimulated macrophages resulted in elevated IL-6 protein concentrations and relative IL-6 and TNFα mRNA levels. Conditioned medium from LPS-stimulated macrophages also induced NFκB translocation and increased caspase-3/7 activation in cardiomyocytes. Analyzing the role of different cardiac receptors, we found that TLR4 and TNFR inhibition reduces cardiac inflammation and that the inhibition of TNFR prevents NFκB translocation into the nuclei of cardiomyocytes, induced by exposure to conditioned medium of proinflammatory macrophages. Moreover, we demonstrated that TLR3 inhibition reduces macrophage-mediated caspase-3/7 activation. Our results suggest that the immune response of macrophages under inflammatory conditions leads to the release of DAMPs, such as eRNA and cytokines, which in turn induce cardiomyocyte dysfunction. Thus, the data obtained in this study contribute to a better understanding of the pathophysiological mechanisms of cardiac dysfunction.

RanGTPase links nucleo-cytoplasmic transport to the recruitment of cargoes into small extracellular vesicles

Small extracellular vesicle (sEV)-mediated intercellular communication regulates multiple aspects of growth and development in multicellular organisms. However, the mechanism underlying cargo recruitment into sEVs is currently unclear. We show that the key nucleo-cytoplasmic transport (NCT) protein-RanGTPase, in its GTP-bound form (RanGTP), is enriched in sEVs secreted by mammalian cells. This recruitment of RanGTP into sEVs depends on the export receptor CRM1 (also called XPO1). The recruitment of GAPDH, a candidate cargo protein, into sEVs is regulated by the RanGTP-CRM1axis in a nuclear export signal (NES)-dependent manner. Perturbation of NCT through overexpression or depletion of nuclear transport components affected the recruitment of Ran, CRM1 and GAPDH into sEVs. Our studies, thus, suggest a link between NCT, particularly the Ran-CRM1 axis, and recruitment of NES-containing cargoes into the sEVs. Collectively, these findings implicate RanGTPase as a link between NCT and sEV mediated intercellular communication.

HMGB1 is a critical molecule in the pathogenesis of Gram-negative sepsis

Gram-negative sepsis is a severe clinical syndrome associated with significant morbidity and mortality. Lipopolysaccharide (LPS), expressed on Gram-negative bacteria, is a potent pro-inflammatory toxin that induces inflammation and coagulation via two separate receptor systems. One is Toll-like receptor 4 (TLR4), expressed on cell surfaces and in endosomes, and the other is the cytosolic receptor caspase-11 (caspases-4 and -5 in humans). Extracellular LPS binds to high mobility group box 1 (HMGB1) protein, a cytokine-like molecule. The HMGB1-LPS complex is transported via receptor for advanced glycated end products (RAGE)-endocytosis to the endolysosomal system to reach the cytosolic LPS receptor caspase-11 to induce HMGB1 release, inflammation, and coagulation that may cause multi-organ failure. The insight that LPS needs HMGB1 assistance to generate severe inflammation has led to successful therapeutic results in preclinical Gram-negative sepsis studies targeting HMGB1. However, to date, no clinical studies have been performed based on this strategy. HMGB1 is also actively released by peripheral sensory nerves and this mechanism is fundamental for the initiation and propagation of inflammation during tissue injury. Homeostasis is achieved when other neurons actively restrict the inflammatory response via monitoring by the central nervous system and the vagus nerve through the cholinergic anti-inflammatory pathway. The neuronal control in Gram-negative sepsis needs further studies since a deeper understanding of the interplay between HMGB1 and acetylcholine may have beneficial therapeutic implications. Herein, we review the synergistic overlapping mechanisms of LPS and HMGB1 and discuss future treatment opportunities in Gram-negative sepsis.

Cold Stress Induced Liver Injury of Mice through Activated NLRP3/Caspase-1/GSDMD Pyroptosis Signaling Pathway

The body needs to generate heat to ensure basic life activities when exposed to cold temperatures. The liver, as the largest glycogen storage organ in the body and main heat-producing organ at rest, may play a role in chronic cold exposure. Recent studies suggested that pyroptosis plays a crucial role in liver diseases. However, the role of pyroptosis in cold stress-induced liver injury is not clear. Hence, in this study, we attempted to investigate the effects of chronic cold exposure on liver function, apoptosis, oxidative stress and inflammation in mice by establishing a mouse model of chronic cold exposure, and to investigate whether pyroptosis pathways are involved in the process of chronic cold exposure. In vivo, our results show that inflammatory cell infiltration and other pathological changes in liver cells and the activity of liver enzyme evidently increased in the serum and liver of cold-exposed mice, suggesting cold stress may result in liver injury. Remarkably, increased expression of heat shock protein 70 (HSP70) and HSP90 proteins proved the cold stress model is successfully constructed. Then, elevated levels of apoptosis, inflammation, oxidative stress and pyroptosis related proteins and mRNAs, such as cysteinyl aspartate specific proteinase-3 (Caspase-3), inducible nitric oxide synthase (iNOS), nuclear factor erythroid2-related factor 2 (Nrf2) and gasdermins D (GSDMD), confirmed that cold exposure activated apoptosis, oxidative stress and pyroptosis, and released inflammation cytokines. Meanwhile, in vitro, we got similar results as in vivo. Further, adding an NLR family pyrin domain containing 3 (NLRP3) inhibitors found that suppression expression of NLRP3 results in the essential proteins of pyroptosis and antioxidant evidently reduced, and adding GSDMD inhibitor found that suppression expression of GSDMD accompanies with the level of Nrf2 and heme oxygenase-1 (HO-1) obviously reduced. In summary, these findings provide a new understanding of the underlying mechanisms of the cold stress response, which can inform the development of new strategies to combat the effects of hypothermia.