The Role of Autophagy and NLRP3 Inflammasome in Liver Fibrosis

Thiazole isomers as potential ALK5 inhibitors alleviate P2X7R-mediated inflammation during liver fibrosis

Liver fibrosis is a critical precursor to the progression of cirrhosis and liver cancer. However, the development of precision therapies for this condition has been impeded by incompletely elucidated molecular mechanisms. Activin receptor like kinase 5 (ALK5), termed TGF-β type I receptor (TGF-βRI), has been identified as a promising therapeutic target for antifibrotic drug development. In this study, we designed and synthesized two novel thiazole derivatives (J-1155 and J-1156) featuring enantiomeric amino acid moieties to selectively target ALK5 for hepatic fibrosis treatment. Our data demonstrated that both compounds effectively attenuate hepatic fibrosis and associated inflammation through dual inhibition of the TGF-β/Smad signaling pathway and blockade of the P2X7R-NLRP3 inflammasome axis. In comparison, J-1156 demonstrated superior overall therapeutic efficacy to J-1155 in terms of anti-fibrotic efficacy, while J-1155 exhibited superior modulation of Smurf2. Collectively, our observations demonstrate the potential of J-1155 and J-1156 as dual novel therapeutic agents targeting hepatic fibrosis.

SLC26A4 regulates autophagy and activates the NLRP3 inflammasome to mediate pathological cardiac hypertrophy

Solute carrier family 26 member 4 (SLC26A4) plays an essential role in the progression of pathological cardiac hypertrophy. This study aimed to examine the involvement of SLC26A4 in cardiac hypertrophy by regulation of autophagy and activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome. Cardiomyocytes were treated with 200 µmol/L phenylephrine (PE) to induce cardiac hypertrophy, followed by treatment with 10 mmol/L INF39, an NLRP3 inhibitor. Furthermore, the pLL3.7 lentiviral vector was used to construct a sh-SLC26A4 interference plasmid and a PLL3.7-cardiomyocytesv-SLC26A4 overexpression plasmid to intervene in PE-induced cardiac hypertrophy. Quantitative reverse transcription polymerase chain reaction and Western blotting were performed to measure the expression of ANP, BNP, β-MHC, SLC26A4, NLRP3, apoptosis associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), and caspase-1. Immunofluorescence was used to detect the level of α-smooth muscle actin (α-SMA) to indicate the cardiomyocyte area. The expression levels of the autophagy proteins LC3, beclin-1, and p62 were determined by Western blotting. Finally, an SD rats model of cardiac hypertrophy was established using transverse aortic constriction (TAC) surgery. SLC26A4, NLRP3, IL-1β, ACS and caspase-1 were further examined at gene and protein levels. SLC26A4 expression was associated with cardiac hypertrophy in cell experiments. SLC26A4 promoted autophagy and activation of the NLRP3 inflammasome pathway, regulating the gene and protein expression of LC3, beclin-1, p62, ACS, NLRP3, and caspase-1. Similar results were observed in the TAC rat model, in which SLC26A4 expression was associated with cardiomyocyte enlargement and cardiac interstitial and perivascular fibrosis. SLC26A4 was involved in cardiac hypertrophy by promoting autophagy and activating the NLRP3 inflammasome pathway. Targeting the expression of SLC26A4 may provide a new treatment option for cardiac hypertrophy.

The Protective Role of Baicalin in the Regulation of NLRP3 Inflammasome in Different Diseases

The NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome consists of pro-caspase-1, NLRP3 and apoptosis-related speckle-like protein (ASC). It can detect multiple microorganisms, endogenous danger signals and environmental stimulus including adenosine triphosphate (ATP), urate, cholesterol crystals, and so on, thereby forming activated NLRP3 inflammasome. During the course of the activation of NLRP3 inflammasome, pro-caspase-1 is transformed into activated caspase-1 that results in the maturation and secretion of interleukin-1beta (IL-1β) and IL-18. The dysfunction of NLRP3 inflammasome participates in multiple diseases such as liver diseases, renal diseases, nervous system diseases and diabetes. Baicalin is the primary bioactive component of Scutellaria baicalensis, which has been used since ancient times. Baicalin has many types of biological functions, such as anti-bacterial, anti-tumor and antioxidant. More and more evidence suggests that baicalin regulation of NLRP3 inflammasome is involved in different diseases. However, the mechanism is still elusive. Here, we reviewed the progress of baicalin regulation of NLRP3 inflammasome in many kinds of diseases to lay a foundation for future researches.

The NLRP3 inflammasome: Mechanisms of activation, regulation, and role in diseases

Because of numerous stress signals, intracellular protein complexes are called inflammasomes. They function as catalysts for the proteolytic transformation of pro-interleukin into the active form of interleukin. Inflammasomes can promote a type of cell death process known as pyroptosis. The NLRP3 inflammasome, comprised of the NLRP3 protein, procaspase-1, and ASC, tightly regulates inflammation. The NLRP3 inflammasome is activated by a variety of stimuli, and several molecular and cellular events, such as ion influx, mitochondrial dysfunction, reactive oxygen species production, and lysosomal damage have been shown to trigger its activation. Inflammation plays a major role in almost all types of human diseases. The NLRP3 inflammasome has been the most widely studied and plays an important pathogenic role in various inflammatory pathologies. This review briefly presents the basic features of NLRP3 inflammasome and their mechanisms of activation and regulation. In addition, recent studies report the role of NLRP3 inflammasome in several diseases have been summarized.

Targeting SIRT2 in Aging-Associated Fibrosis Pathophysiology

Aging is a complex biological process that involves multi-level structural and physiological changes. Aging is a major risk factor for many chronic diseases. The accumulation of senescent cells changes the tissue microenvironment and is closely associated with the occurrence and development of tissue and organ fibrosis. Fibrosis is the result of dysregulated tissue repair response in the development of chronic inflammatory diseases. Recent studies have clearly indicated that SIRT2 is involved in regulating the progression of fibrosis, making it a potential target for anti-fibrotic drugs. SIRT2 is a NAD+ dependent histone deacetylase, shuttling between nucleus and cytoplasm, and is highly expressed in liver, kidney and heart, playing an important role in the occurrence and development of aging and fibrosis. Therefore, we summarized the role of SIRT2 in liver, kidney and cardiac fibrosis during aging.

The hepatoprotective effect of 4-phenyltetrahydroquinolines on carbon tetrachloride induced hepatotoxicity in rats through autophagy inhibition

BACKGROUND

The liver serves as a metabolic hub within the human body, playing a crucial role in various essential functions, such as detoxification, nutrient metabolism, and hormone regulation. Therefore, protecting the liver against endogenous and exogenous insults has become a primary focus in medical research. Consequently, the potential hepatoprotective properties of multiple 4-phenyltetrahydroquinolines inspired us to thoroughly study the influence of four specially designed and synthesized derivatives on carbon tetrachloride (CCl4)-induced liver injury in rats.

METHODS AND RESULTS

Seventy-seven Wistar albino male rats weighing 140 ± 18 g were divided into eleven groups to investigate both the toxicity profile and the hepatoprotective potential of 4-phenyltetrahydroquinolines. An in-vivo hepatotoxicity model was conducted using CCl4 (1 ml/kg body weight, a 1:1 v/v mixture with corn oil, i.p.) every 72 h for 14 days. The concurrent treatment of rats with our newly synthesized compounds (each at a dose of 25 mg/kg body weight, suspended in 0.5% CMC, p.o.) every 24 h effectively lowered transaminases, preserved liver tissue integrity, and mitigated oxidative stress and inflammation. Moreover, the histopathological examination of liver tissues revealed a significant reduction in liver fibrosis, which was further supported by the immunohistochemical analysis of α-SMA. Additionally, the expression of the apoptotic genes BAX and BCL2 was monitored using real-time PCR, which showed a significant decrease in liver apoptosis. Further investigations unveiled the ability of the compounds to significantly decrease the expression of autophagy-related proteins, Beclin-1 and LC3B, consequently inhibiting autophagy. Finally, our computer-assisted simulation dockingonfirmed the obtained experimental activities.

CONCLUSION

Our findings suggest that derivatives of 4-phenyltetrahydroquinoline demonstrate hepatoprotective properties in CCl4-induced liver damage and fibrosis in rats. The potential mechanism of action may be due to the inhibition of autophagy in liver cells.

The Angiotensin II Receptor Neprilysin Inhibitor LCZ696 Inhibits the NLRP3 Inflammasome By Reducing Mitochondrial Dysfunction in Macrophages and Alleviates Dextran Sulfate Sodium-induced Colitis in a Mouse Model

The intracellular sensor protein complex known as the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in regulating inflammatory diseases by overseeing the production of interleukin (IL)-1β and IL-18. Targeting its abnormal activation with drugs holds significant promise for inflammation treatment. This study highlights LCZ696, an angiotensin receptor-neprilysin inhibitor, as an effective suppressor of NLRP3 inflammasome activation in macrophages stimulated by ATP, nigericin, and monosodium urate. LCZ696 also reduces caspase-11 and GSDMD activation, lactate dehydrogenase release, propidium iodide uptake, and the extracellular release of NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) in ATP-activated macrophages, suggesting a potential mitigation of pyroptosis. Mechanistically, LCZ696 lowers mitochondrial reactive oxygen species and preserves mitochondrial integrity. Importantly, it does not significantly impact NLRP3, proIL-1β, inducible nitric oxide synthase, cyclooxygenase-2 expression, or NF-κB activation in lipopolysaccharide-activated macrophages. LCZ696 partially inhibits the NLRP3 inflammasome through the induction of autophagy. In an in vivo context, LCZ696 alleviates NLRP3-associated colitis in a mouse model by reducing colonic expression of IL-1β and tumor necrosis factor-α. Collectively, these findings suggest that LCZ696 holds significant promise as a therapeutic agent for ameliorating NLRP3 inflammasome activation in various inflammatory diseases, extending beyond its established use in hypertension and heart failure treatment.

Ganoderma lucidum ethanol extracts ameliorate hepatic fibrosis and promote the communication between metabolites and gut microbiota g_Ruminococcus through the NF-κB and TGF-β1/Smads pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum, a traditional edible medicinal mushroom, has been widely reported to improve liver diseases as a dietary intervention for people. Ganoderma lucidum extracts, primarily total triterpenoids (GLTTs), are one of the bioactive ingredients that have excellent beneficial effects on hepatic fibrosis. Therefore, its prevention and reversal are particularly critical due to the increasing number of patients with chronic liver diseases worldwide.

AIM OF THE STUDY

The study aimed to evaluate whether GLTTs had a hepatoprotective effect against hepatic fibrosis through metabolic perturbations and gut microbiota changes and its underlying mechanisms.

MATERIALS AND METHODS

The compound compositions of GLTTs were quantified, and carbon tetrachloride (CCl4)-induced hepatic fibrosis rats were used to investigate the cause of the improvement in various physiological states with GLTTs treatment, and to determine whether its consequent effect was associated with endogenous metabolites and gut microbiota using UPLC-Q-TOF-MSE metabolomics and 16S rRNA gene sequencing technology.

RESULTS

GLTTs alleviated physical status, reduced liver pathological indicators, proinflammatory cytokines, and deposition of hepatic collagen fibers via regulating the NF-κB and TGF-β1/Smads pathways. The untargeted metabolomics analysis identified 16 potential metabolites that may be the most relevant metabolites for gut microbiota dysbiosis and the therapeutic effects of GLTTs in hepatic fibrosis. Besides, although GLTTs did not significantly affect the α-diversity indexes, significant changes were observed in the composition of microflora structure. In addition, Spearman analysis revealed strong correlations between endogenous metabolites and gut microbiota g_Ruminococcus with hepatic fibrosis.

CONCLUSION

GLTTs could provide a potential target for the practical design and application of novel functional food ingredients or drugs in the therapy of hepatic fibrosis.

Jiawei Taohe Chengqi decoction inhibition of the notch signal pathway affects macrophage reprogramming to inhibit HSCs activation for the treatment of hepatic fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei Taohe Chengqi Tang (JTCD) is a modified formulation of Traditional Chinese Medicine (TCM) known as Taohe Chengqi Decoction, which has been described in the ancient TCM literature "Treatise on Febrile Diseases". As a formula that can activate blood circulation and eliminate blood stasis and regulate Yin and Yang in traditional Chinese medicine applications, JTCD has been reported to be effective in the treatment of chronic liver disease and hepatic fibrosis (HF).

AIM OF STUDY

The current study aimed to evaluate the effectiveness of JTCD in modulating hepatic macrophages by regulating the Notch signal pathway, and to further investigate the mechanisms underlying macrophage reprogramming that leads to HF.

MATERIALS AND METHODS

Molecular assays were performed using in vitro cultures of human mononuclear THP-1 cells and human-derived hepatic stellate cells LX-2. CCl4-induced mice were utilized as an in vivo model to simulate HF.

RESULTS

Our results demonstrated that JTCD exhibited dual effects by inhibiting hepatic stellate cell (HSCs) activation and modulating the polarisation of macrophages towards the M2 phenotype while decreasing the M1 phenotype. Network pharmacological analyses and molecular docking studies revealed that the Notch signal pathway was significantly enriched and played a crucial role in the therapeutic response of JTCD against HF. Moreover, through the establishment of a co-culture model, we validated that JTCD inhibited the Notch signal pathway in macrophages, leading to alterations in macrophage reprogramming, subsequent inhibition of HSC activation, and ultimately exerting anti-HF effects.

CONCLUSION

In conclusion, our findings provide solid evidence for JTCD in treating HF, as it suppresses the Notch signal pathway in macrophages, regulates macrophage reprogramming, and inhibits HSC activation.

Progress in the Correlation Between Inflammasome NLRP3 and Liver Fibrosis

Liver fibrosis is a reversible condition that occurs in the early stages of chronic liver disease. To develop effective treatments for liver fibrosis, understanding the underlying mechanism is crucial. The NOD-like receptor protein 3 (NLRP3) inflammasome, which is a part of the innate immune system, plays a crucial role in the progression of various inflammatory diseases. NLRP3 activation is also important in the development of various liver diseases, including viral hepatitis, alcoholic or nonalcoholic liver disease, and autoimmune liver disease. This review discusses the role of NLRP3 and its associated molecules in the development of liver fibrosis. It also highlights the signal pathways involved in NLRP3 activation, their downstream effects on liver disease progression, and potential therapeutic targets in liver fibrosis. Further research is encouraged to develop effective treatments for liver fibrosis.

Mechanisms and effects of NLRP3 in digestive cancers

Inflammasomes are thought to be important mediators of host defense against microbial pathogens and maintenance of gastrointestinal tract homeostasis. They can modulate caspase-1 to promote IL-18 and IL-1β secretion and promote phagocytosis induced by bacterial pathogens. NLRP3 is an inflammasome comprising a multiprotein complex assembled by pattern recognition receptors in the cell cytoplasm. It is a crucial component of the innate immune system. Dysregulation of NLRP3 may contribute to inflammatory diseases and intestinal cancers. Recent research suggests that NLRP3 plays an essential role in tumor development; therefore, intensive study of its mechanism is warranted as it could play a key role in the treatment of digestive system tumors. In this review, we discuss the mechanism and role of NLRP3 in tumors of the digestive system and response strategies to modulate NLRP3 for potential use in tumor treatment.

The molecular mechanism of MiR-26a-5p regulates autophagy and activates NLRP3 inflammasome to mediate cardiomyocyte hypertrophy

OBJECTIVE

Many studies have found that miR-26a-5p plays an essential role in the progression of pathological cardiac hypertrophy, however, there is still no evidence on whether miR-26a-5p is related to the activation of autophagy and NLRP3 inflammasome. And the mechanism of miR-26a-5p and NLRP3 inflammasome aggravating pathological cardiac hypertrophy remain unclear.

METHODS

Cardiomyocytes were treated with 200µM PE to induce cardiac hypertrophy and intervened with 10mM NLRP3 inhibitor INF39. In addition, we also used the MiR-26a-5p mimic and inhibitor to transfect PE-induced cardiac hypertrophy. RT-qPCR and western blotting were used to detect the expressions of miR-26a-5p, NLRP3, ASC and Caspase-1 in each group, and we used α-SMA immunofluorescence to detect the change of cardiomyocyte area. The expression levels of autophagy proteins LC3, beclin-1 and p62 were detected by western blotting. Finally, we induced the SD rat cardiac hypertrophy model through aortic constriction (TAC) surgery. In the experimental group, rats were intervened with MiR-26a-5p mimic, MiR-26a-5p inhibitor, autophagy inhibitor 3-MA, and autophagy activator Rapamycin.

RESULTS

In cell experiments, we observed that the expression of miR-26a-5p was associated with cardiomyocyte hypertrophy and increased surface area. Furthermore, miR-26a-5p facilitated autophagy and activated the NLRP3 inflammasome pathway, which caused changes in the expression of genes and proteins including LC3, beclin-1, p62, ACS, NLRP3, and Caspase-1. We discovered similar outcomes in the TAC rat model, where miR-26a-5p expression corresponded with cardiomyocyte enlargement and fibrosis in the cardiac interstitial and perivascular regions. In conclusion, miR-26a-5p has the potential to regulate autophagy and activate the NLRP3 inflammasome, contributing to the development of cardiomyocyte hypertrophy.

CONCLUSION

Our study found a relationship between the expression of miR-26a-5p and cardiomyocyte hypertrophy. The mechanism behind this relationship appears to involve the activation of the NLRP3 inflammasome pathway, which is caused by miR-26a-5p promoting autophagy. Targeting the expression of miR-26a-5p, as well as inhibiting the activation of autophagy and the NLRP3 inflammasome pathway, could offer additional treatments for pathological cardiac hypertrophy.

Hepatic NLRP3-Derived Hsp70 Binding to TLR4 Mediates MASLD to MASH Progression upon Inhibition of PP2A by Harmful Algal Bloom Toxin Microcystin, a Second Hit

Harmful algal bloom toxin microcystin has been associated with metabolic dysfunction-associated steatotic liver disease (MASLD) progression and hepatocellular carcinoma, though the mechanisms remain unclear. Using an established mouse model of MASLD, we show that the NLRP3-Hsp70-TLR4 axis drives in part the inflammation of the liver lobule that results in the progression of MASLD to metabolic dysfunction-associated steatohepatitis (MASH). Results showed that mice deficient in NLRP3 exhibited decreased MASH pathology, blocked Hsp70 expression, and co-binding with NLRP3, a crucial protein component of the liver inflammasome. Hsp70, both in the liver lobule and extracellularly released in the liver vasculature, acted as a ligand to TLR4 in the liver, primarily in hepatocytes to activate the NF-κB pathway, ultimately leading to hepatic cell death and necroptosis, a crucial pathology of MASH progression. The above studies show a novel insight into an inflammasome-triggered Hsp70-mediated inflammation that may have broader implications in MASLD pathology. MASLD to MASH progression often requires multiple hits. One of the mediators of progressive MASLD is environmental toxins. In this research report, we show for the first time a novel mechanism where microcystin-LR, an environmental toxin, advances MASLD to MASH by triggering the release of Hsp70 as a DAMP to activate TLR4-induced inflammation in the liver.

Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells

BACKGROUND

Liver fibrosis is the common pathological process associated with the occurrence and development of various chronic liver diseases. At present, there is still a lack of effective prevention and treatment methods in clinical practice. Hepatic stellate cell (HSC) plays a key role in liver fibrogenesis. In recent years, the study of liver fibrosis targeting HSC autophagy has become a hot spot in this research field. Angiotensin-converting enzyme 2 (ACE2) is a key negative regulator of renin-angiotensin system, and its specific molecular mechanism on autophagy and liver fibrosis needs to be further explored.

AIM

To investigate the effect of ACE2 on hepatic fibrosis in mice by regulating HSC autophagy through the Adenosine monophosphate activates protein kinases (AMPK)/mammalian target of rapamycin (mTOR) pathway.

METHODS

Overexpression of ACE2 in a mouse liver fibrosis model was induced by injection of liver-specific recombinant adeno-associated virus ACE2 vector (rAAV2/8-ACE2). The degree of liver fibrosis was assessed by histopathological staining and the biomarkers in mouse serum were measured by Luminex multifactor analysis. The number of apoptotic HSCs was assessed by terminal deoxynucleoitidyl transferase-mediated dUTP nick-end labeling (TUNEL) and immunofluorescence staining. Transmission electron microscopy was used to identify the changes in the number of HSC autophagosomes. The effect of ACE2 overexpression on autophagy-related proteins was evaluated by multicolor immunofluorescence staining. The expression of autophagy-related indicators and AMPK pathway-related proteins was measured by western blotting.

RESULTS

A mouse model of liver fibrosis was successfully established after 8 wk of intraperitoneal injection of carbon tetrachloride (CCl4). rAAV2/8-ACE2 administration reduced collagen deposition and alleviated the degree of liver fibrosis in mice. The serum levels of platelet-derived growth factor, angiopoietin-2, vascular endothelial growth factor and angiotensin II were decreased, while the levels of interleukin (IL)-10 and angiotensin- (1-7) were increased in the rAAV2/8-ACE2 group. In addition, the expression of alpha-smooth muscle actin, fibronectin, and CD31 was down-regulated in the rAAV2/8-ACE2 group. TUNEL and immunofluorescence staining showed that rAAV2/8-ACE2 injection increased HSC apoptosis. Moreover, rAAV2/8-ACE2 injection notably decreased the number of autophagosomes and the expression of autophagy-related proteins (LC3I, LC3II, Beclin-1), and affected the expression of AMPK pathway-related proteins (AMPK, p-AMPK, p-mTOR).

CONCLUSION

ACE2 overexpression can inhibit HSC activation and promote cell apoptosis by regulating HSC autophagy through the AMPK/mTOR pathway, thereby alleviating liver fibrosis and hepatic sinusoidal remodeling.

Salvianolic acid B inhibits hepatic stellate cell activation and liver fibrosis by targeting PDGFRβ

Liver fibrosis is a reversible pathological process and a wound healing response to liver injury. As an early stage of various liver diseases, liver fibrosis can develop into cirrhosis, liver failure, and even liver cancer if not controlled in time. Salvia miltiorrhiza is a medicinal plant with hepatoprotective effects. Salvianolic acid B (Sal B) is the representative component of S. miltiorrhiza. Many studies have reported the anti-liver fibrosis effects and mechanisms of Sal B. However, the direct anti-fibrotic targets of Sal B have not yet been reported. Platelet-derived growth factor receptor β (PDGFRβ) is one of the most classical targets in liver fibrosis, which is closely related to hepatic stellate cells (HSCs) activated. Previously, we established and applied a PDGFRβ affinity chromatography model, and found that Sal B binds well to PDGFRβ. Therefore, this study aimed to investigate the direct targets of Sal B against liver fibrosis. We confirmed the binding ability of Sal B to PDGFRβ by molecular docking and a surface plasmon resonance biosensor. Our findings indicated that Sal B targeted PDGFRβ to inhibit the activation, migration and proliferation of HSCs and suppressed the PDGF-BB-induced PDGFRβ signaling pathway. Annexin V-FITC/PI assay showed that Sal B reversed the PDGF-BB-induced decrease in HSC apoptosis rate. In the mouse liver fibrosis model, Sal B inhibited the PDGFRβ signaling pathway, HSC activation and reduced inflammatory response, ultimately improved CCl4-induced liver fibrosis. In summary, the direct anti-fibrotic targets of Sal B may be PDGFRβ, and this study clarified the anti-liver fibrosis effects and mechanism of Sal B.

Liver Fibrosis Resolution: From Molecular Mechanisms to Therapeutic Opportunities

The liver is a critical system for metabolism in human beings, which plays an essential role in an abundance of physiological processes and is vulnerable to endogenous or exogenous injuries. After the damage to the liver, a type of aberrant wound healing response known as liver fibrosis may happen, which can result in an excessive accumulation of extracellular matrix (ECM) and then cause cirrhosis or hepatocellular carcinoma (HCC), seriously endangering human health and causing a great economic burden. However, few effective anti-fibrotic medications are clinically available to treat liver fibrosis. The most efficient approach to liver fibrosis prevention and treatment currently is to eliminate its causes, but this approach's efficiency is too slow, or some causes cannot be fully eliminated, which causes liver fibrosis to worsen. In cases of advanced fibrosis, the only available treatment is liver transplantation. Therefore, new treatments or therapeutic agents need to be explored to stop the further development of early liver fibrosis or to reverse the fibrosis process to achieve liver fibrosis resolution. Understanding the mechanisms that lead to the development of liver fibrosis is necessary to find new therapeutic targets and drugs. The complex process of liver fibrosis is regulated by a variety of cells and cytokines, among which hepatic stellate cells (HSCs) are the essential cells, and their continued activation will lead to further progression of liver fibrosis. It has been found that inhibiting HSC activation, or inducing apoptosis, and inactivating activated hepatic stellate cells (aHSCs) can reverse fibrosis and thus achieve liver fibrosis regression. Hence, this review will concentrate on how HSCs become activated during liver fibrosis, including intercellular interactions and related signaling pathways, as well as targeting HSCs or liver fibrosis signaling pathways to achieve the resolution of liver fibrosis. Finally, new therapeutic compounds targeting liver fibrosis are summarized to provide more options for the therapy of liver fibrosis.

SEMtree: tree-based structure learning methods with structural equation models

MOTIVATION

With the exponential growth of expression and protein-protein interaction (PPI) data, the identification of functional modules in PPI networks that show striking changes in molecular activity or phenotypic signatures becomes of particular interest to reveal process-specific information that is correlated with cellular or disease states. This requires both the identification of network nodes with reliability scores and the availability of an efficient technique to locate the network regions with the highest scores. In the literature, a number of heuristic methods have been suggested. We propose SEMtree(), a set of tree-based structure discovery algorithms, combining graph and statistically interpretable parameters together with a user-friendly R package based on structural equation models framework.

RESULTS

Condition-specific changes from differential expression and gene-gene co-expression are recovered with statistical testing of node, directed edge, and directed path difference between groups. In the end, from a list of seed (i.e. disease) genes or gene P-values, the perturbed modules with undirected edges are generated with five state-of-the-art active subnetwork detection methods. The latter are supplied to causal additive trees based on Chu-Liu-Edmonds' algorithm (Chow and Liu, Approximating discrete probability distributions with dependence trees. IEEE Trans Inform Theory 1968;14:462-7) in SEMtree() to be converted in directed trees. This conversion allows to compare the methods in terms of directed active subnetworks. We applied SEMtree() to both Coronavirus disease (COVID-19) RNA-seq dataset (GEO accession: GSE172114) and simulated datasets with various differential expression patterns. Compared to existing methods, SEMtree() is able to capture biologically relevant subnetworks with simple visualization of directed paths, good perturbation extraction, and classifier performance.

AVAILABILITY AND IMPLEMENTATION

SEMtree() function is implemented in the R package SEMgraph, easily available at https://CRAN.R-project.org/package=SEMgraph.

Research and progress of inflammasomes in nonalcoholic fatty liver disease

With the development of the social economy, unhealthy living habits and eating styles are gradually affecting people's health in recent years. As a chronic liver disease, NAFLD is deeply affected by unhealthy living habits and eating styles and has gradually become an increasingly serious public health problem. As a protein complex in clinical research, the inflammasomes play a crucial role in the development of NAFLD, atherosclerosis, and other diseases. This paper reviews the types, composition, characteristics of inflammasomes, and molecular mechanism of the inflammasome in NAFLD. Meanwhile, the paper reviews the drugs and non-drugs that target NLRP3 inflammasome in the treatment of NAFLD in the past decades. we also analyzed and summarized the related experimental models, mechanisms, and results of NAFLD. Although current therapeutic strategies for NAFLD are not effective, we expect that we will be able to find an appropriate treatment to address this problem in the future with further research on inflammasome.

Hepatic-Modulatory Effects of Chicken Liver Hydrolysate-Based Supplement on Autophagy Regulation against Liver Fibrogenesis

Chicken-liver hydrolysates (CLHs) have been characterized as performing several biofunctions by our team. This study aimed to investigate if a CLH-based supplement (GBHP01^TM) can ameliorate liver fibrogenesis induced by thioacetamide (TAA) treatment. Our results showed that the TAA treatment caused lower body weight gains and enlarged livers, as well as higher serum ALT, AST, and ALP levels (p < 0.05). This liver inflammatory and fibrotic evidence was ameliorated (p < 0.05) by supplementing with GBHP01^TM; this partially resulted from its antioxidant abilities, including decreased TBARS values but increased TEAC levels, reduced GSH contents and catalase/GPx activities in the livers of TAA-treated rats (p < 0.05). Additionally, fewer nodules were observed in the appearance of the livers of TAA-treated rats after supplementing with GBHP01^TM. Similarly, supplementing GBHP01^TM decreased fibrotic scars and the fibrotic score in the livers of TAA-treated rats (p < 0.05). Moreover, the increased hepatic IL-6, IL-1β, and TNF-α levels after TAA treatment were also alleviated by supplementing with GBHP01^TM (p < 0.05). Meanwhile, GBHP01^TM could decrease the ratio of LC3B II/LC3B I, but upregulated P62 and Rab7 in the livers of TAA-treated rats (p < 0.05). Taking these results together, the CLH-based supplement (GBHP01^TM) can be characterized as a natural agent against liver fibrogenesis.

Regulatory Functions and Mechanisms of Circular RNAs in Hepatic Stellate Cell Activation and Liver Fibrosis

Chronic liver injury induces the activation of hepatic stellate cells (HSCs) into myofibroblasts, which produce excessive amounts of extracellular matrix (ECM), resulting in tissue fibrosis. If the injury persists, these fibrous scars could be permanent and disrupt liver architecture and function. Currently, effective anti-fibrotic therapies are lacking; hence, understanding molecular mechanisms that control HSC activation could hold a key to the development of new treatments. Recently, emerging studies have revealed roles of circular RNAs (circRNAs), a class of non-coding RNAs that was initially assumed to be the result of splicing errors, as new regulators in HSC activation. These circRNAs can modulate the activity of microRNAs (miRNAs) and their interacting protein partners involved in regulating fibrogenic signaling cascades. In this review, we will summarize the current knowledge of this class of non-coding RNAs for their molecular function in HSC activation and liver fibrosis progression.

The role of NLRP3 inflammasome in hepatocellular carcinoma

Inflammasomes play an important role in innate immunity. As a signal platform, they deal with the excessive pathogenic products and cellular products related to stress and injury. So far, the best studied and most characteristic inflammasome is the NLR-family pyrin domain-containing protein 3(NLRP3) inflammasome, which is composed of NLRP3, apoptosis associated speck like protein (ASC) and pro-caspase-1. The formation of NLRP3 inflammasome complexes results in the activation of caspase-1, the maturation of interleukin (IL)-1β and IL-18, and pyroptosis. Many studies have demonstrated that NLRP3 inflammasome not only participates in tumorigenesis, but also plays a protective role in some cancers. Hepatocellular carcinoma (HCC) is a major cause of cancer-related mortality. Currently, due to the lack of effective treatment methods for HCC, the therapeutic effect of HCC has not been ideal. Therefore, it is particularly urgent to explore the pathogenesis of HCC and find its effective treatment methods. The increasing evidences indicate that NLRP3 inflammasome plays a vital role in HCC, however, the related mechanisms are not fully understood. Hence, we focused on the recent progress about the role of NLRP3 inflammasome in HCC, and analyzed the relevant mechanisms in detail to provide reference for the future in-depth researches.

Peptide mediated therapy in fibrosis: Mechanisms, advances and prospects

Fibrosis, a disease characterized by an excess accumulation of extracellular matrix components, could lead to organ failure and death, and is to blame for up to 45 % of all fatalities in developed nations. These disorders all share the common trait of an unchecked and increasing accumulation of fibrotic tissue in the affected organs, which leads to their malfunction and eventual failure, even if their underlying causes are highly diverse and, in some cases, remain unclear. Numerous studies have identified activated myofibroblasts as the common cellular elements ultimately responsible for the replacement of normal tissues with nonfunctional fibrotic tissue. The transforming growth factor-β pathway, for instance, plays a significant role in practically all kinds of fibrosis. However, there is no specific drug for the treatment of fibrosis, several medications with anti-hepatic fibrosis properties are still in the research and development stages. Peptide, which refers to a substance consisting of 2-50 amino acids, is characterized by structural diversity, low toxicity, biological activities, easy absorption, specific targeting, few side effects, and has been proven to be effective in anti-fibrosis. Here, we summarized various anti-fibrosis peptides in fibrosis including the liver, lungs, kidneys, and other organs. This review will provide a new insight into peptide mediated anti-fibrosis and is helpful to creation of antifibrotic medications.

Revealing immune infiltrate characteristics and potential immune-related genes in hepatic fibrosis: based on bioinformatics, transcriptomics and q-PCR experiments

Background

The occurrence and progression of hepatic fibrosis (HF) is accompanied by inflammatory damage. Immune genes play a pivotal role in fibrogenesis and inflammatory damage in HF by regulating immune cell infiltration. However, the immune mechanisms of HF are inadequately studied. Therefore, this research aims to identify the immune genes and biological pathway which involved in fibrosis formation and inflammatory damage in HF and explore immune target-based therapeutics for HF.

Methods

The expression dataset GSE84044 of HF was downloaded from the GEO database. The crucial module genes for HF were screened according to weighted gene co-expression network analysis (WGCNA). The crucial module genes were mapped to immune-related genes obtained from the ImmPort database to obtain the hepatic fibrosis immune genes (HFIGs). In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses were performed on HFIGs. Then, the protein-protein interaction (PPI) network was conducted on HFIGs and hub genes were identified from the PPI network. Moreover, immune infiltration analysis was performed to identified correlation between hub gene and immune cell infiltration. To verify the reliability of the GSE84044 expression profile data analysis, a rat model of CCl4-induced HF was established, followed by transcriptome sequencing and immunofluorescence analysis and quantitative reverse transcription (q-PCR) experiments were performed in HF rats and normal rat liver tissues. Finally, CMAP platform was used to explore immune target-based therapeutics for HF.

Results

In the bioinformatics analysis of GSE84044 data, 98 HFIGs were screened. These genes were mainly involved in inflammation-related biological pathways such as NOD-like receptor signaling pathway, NF-kappa B signaling pathway, Toll-like receptor signaling pathway and PI3K-Akt signaling pathway. From the PPI network, 10 hub genes were identified, including CXCL8, IL18, CXCL10, CD8A, IL7, PTPRC, CCL5, IL7R, CXCL9 and CCL2. Immune infiltration analysis showed that immune cells like neutrophils, natural killer (NK) cells, macrophages M1 and macrophages M2 were significantly correlated with the hepatic fibrosis process and hub gene expression was significantly correlated with these immune cells. Notably, most of the biological pathways HFIGs riched and all the hub gene expression except CXCL8 were validated in subsequent transcriptome and qRCR experiments. Finally, 15 small molecule compounds with the potential to reverse the high expression of hub genes were screen out as potential therapeutic agents for HF.

Conclusion

The immune genes CXCL8, IL18, CXCL10, CD8A, IL7, PTPRC, CCL5, IL7R, CXCL9 and CCL2 may play an essential role in the fibrosis formation and inflammatory damage in HF. The outcomes of this research provide a basis for the study of the immune mechanisms of HF and contribute to the diagnosis and prevention and treatment of HF in clinical practice.

The role of NLRP3 inflammasome in digestive system malignancy

Digestive system malignancies, the most common types of cancer and a major cause of death in the worldwide, are generally characterized by high morbidity, insidious symptoms and poor prognosis. NLRP3 inflammasome, the most studied inflammasome member, is considered to be crucial in tumorigenesis. In this paper, we reviewed its pro-tumorigenic and anti-tumorigenic properties in different types of digestive system malignancy depending on the types of cells, tissues and organs involved, which would provide promising avenue for exploring new anti-cancer therapies.

Protective Effect and Mechanism of Placenta Extract on Liver

The placenta contains multiple biologically active substances, which exert antioxidation, anti-inflammatory, immunomodulatory, and delayed aging effects. Its extract can improve hepatic morphology and function: on the one hand, it can reduce liver interstitial collagen deposition, lipogenesis, and inflammatory cell infiltration and improve fibrosis; on the other hand, it can prevent hepatocellular degeneration by scavenging reactive oxygen species (ROS) and inhibiting inflammatory cytokine production, further improve hepatocyte apoptosis and necrosis, and promote hepatocyte regeneration, making it a promising liver-protective agent. Current research on placenta extract (PE) mainly focuses on treating a specific type of liver injury, and there are no systematic reports. Therefore, this review comprehensively summarizes the treatment reports of PE on liver injury and analyzes its mechanism of action.

Significance of elevated serum and hepatic NOD-like receptor pyrin domain containing 3 (NLRP3) in hepatitis C virus-related liver disease

NOD-like receptor pyrin domain containing 3 (NLRP3) is a microbial and danger signal sensor that acts as a regulator of inflammation via activation of Caspase-1 (CASP1) and has been identified as a major contributor to human liver diseases. The present study was conducted to investigate the association between NLRP3 and the progression of hepatitis C virus (HCV)-related liver disease. Serum NLRP3 levels were analyzed in 49 patients with chronic HCV infection and 18 healthy controls and liver tissues from 34 patients were examined to assess the protein expression of NLRP3 and its activation marker CASP1 using immunohistochemical staining. The results showed that the median serum NLRP3 levels was significantly higher in HCV-infected patients compared with healthy controls (1040 pg/ml vs 695 pg/ml respectively, P < 0.001) and were positively correlated with hepatic NLRP3 and CASP1 expression (r = 0.749, P < 0.001 and r = 0.557, P = 0.001 respectively). The NLRP3 levels in serum and the liver significantly increased with worsening liver pathology and showed positive correlations with serum aminotransferases levels, HCV viremia, and albumin-bilirubin score (P < 0.05). The receiver operating characteristic curve analysis revealed a high diagnostic performance of serum NLRP3 in determining the extent of liver necroinflammation, fibrosis, and steatosis (area under the curve = 0.951, 0.971, and 0.917 respectively, P < 0.001). In conclusion, NLRP3 plays an important role in liver disease progression during HCV infection via CASP1 activation and might be a promising therapeutic target. Serum NLRP3 could be an additional biomarker for liver inflammation and fibrosis.

NLRP3 inflammasome in digestive diseases: From mechanism to therapy

Digestive system diseases remain a formidable challenge to human health. NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most characteristic multimeric protein complex and is involved in a wide range of digestive diseases as intracellular innate immune sensors. It has emerged as a research hotspot in recent years. In this context, we provide a comprehensive review of NLRP3 inflammasome priming and activation in the pathogenesis of digestive diseases, including clinical and preclinical studies. Moreover, the scientific evidence of small-molecule chemical drugs, biologics, and phytochemicals, which acts on different steps of the NLRP3 inflammasome, is reviewed. Above all, deep interrogation of the NLRP3 inflammasome is a better insight of the pathomechanism of digestive diseases. We believe that the NLRP3 inflammasome will hold promise as a novel valuable target and research direction for treating digestive disorders.

Traditional Chinese medicine: An important source for discovering candidate agents against hepatic fibrosis

Hepatic fibrosis (HF) refers to the pathophysiological process of connective tissue dysplasia in the liver caused by various pathogenic factors. Nowadays, HF is becoming a severe threat to the health of human being. However, the drugs available for treating HF are limited. Currently, increasing natural agents derived from traditional Chinese medicines (TCMs) have been found to be beneficial for HF. A systemic literature search was conducted from PubMed, GeenMedical, Sci-Hub, CNKI, Google Scholar and Baidu Scholar, with the keywords of "traditional Chinese medicine," "herbal medicine," "natural agents," "liver diseases," and "hepatic fibrosis." So far, more than 76 natural monomers have been isolated and identified from the TCMs with inhibitory effect on HF, including alkaloids, flavones, quinones, terpenoids, saponins, phenylpropanoids, and polysaccharides, etc. The anti-hepatic fibrosis effects of these compounds include hepatoprotection, inhibition of hepatic stellate cells (HSC) activation, regulation of extracellular matrix (ECM) synthesis & secretion, regulation of autophagy, and antioxidant & anti-inflammation, etc. Natural compounds and extracts from TCMs are promising agents for the prevention and treatment of HF, and this review would be of great significance to development of novel drugs for treating HF.

Multi-Omics Analysis of the Tumor Microenvironment in Liver Metastasis of Colorectal Cancer Identified FJX1 as a Novel Biomarker

Colorectal cancer incidence and mortality have increased in recent years, with more than half of patients who died of colorectal cancer developing liver metastases. Consequently, colorectal cancer liver metastasis is the focus of clinical treatment, as well as being the most difficult. The primary target genes related to colorectal cancer liver metastasis were via bioinformatics analysis. First, five prognosis-related genes, CTAG1A, CSTL1, FJX1, IER5L, and KLHL35, were identified through screening, and the prognosis of the CSTL1, FJX1, IER5L, and KLHL35 high expression group was considerably poorer than that of the low expression group. Furthermore, the clinical correlation analysis revealed that in distinct pathological stages T, N, and M, the mRNA expression levels of CSTL1, IER5L, and KLHL35 were higher than in normal tissues. Finally, a correlation study of the above genes and clinical manifestations revealed that FJX1 was strongly linked to colorectal cancer liver metastasis. FJX1 is thought to affect chromogenic modification enzymes, the Notch signaling system, cell senescence, and other signaling pathways, according to KEGG enrichment analysis. FJX1 may be a critical target in colorectal cancer metastasis, and thus has the potential as a new biomarker to predict and treat colorectal cancer liver metastases.

Ginsenoside Rh2 attenuates CDAHFD-induced liver fibrosis in mice by improving intestinal microbial composition and regulating LPS-mediated autophagy

BACKGROUND

Nowadays, liver diseases are threatening more and more people all over the world and one of the main causes is liver fibrosis. However, there is no effective way to reverse liver fibrosis.

PURPOSE

To investigate whether ginsenoside Rh2 (G-Rh2) can alleviate liver fibrosis and elucidate its underlying mechanism.

METHODS

In vivo and in vitro methods were adopted in this research. Choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) was used to feed mice to induce liver fibrosis, and HSC-T6 cells were used to establish an LPS-induced model of liver fibrosis. Through histopathological staining, hematoxylin-eosin (H&E) staining, western blot analysis, intestinal bacteria 16SrRNA sequencing, and other technical means, the research explored whether G-Rh2 possesses anti-fibrotic activity.

RESULTS

G-Rh2 could notably alleviate CDAHFD-induced liver fibrosis in mice. In particular, it could alleviate liver injury and reduce plasma lipopolysaccharide (LPS) levels. Additionally, G-Rh2 could repair intestinal injury as well as regulate intestinal microbial diversity and composition. HSC-T6 cells could be activated and autophagy could be induced further by LPS in vitro. After being treated with G-Rh2, autophagy was restrained and activation of hepatic stellate cells (HSCs) was controlled. Deeper research showed that G-Rh2 restrained the activation of HSCs via stimulating the AKT-mTOR signaling pathway, restraining autophagy.

CONCLUSION

The results of our studies clearly suggest that G-Rh2 repairs intestinal injury, improves intestinal microbial composition, reduces plasma LPS levels, and activates the AKT-mTOR signaling pathway to restrain LPS-mediated autophagy, thus playing an important role in anti-hepatic fibrosis. G-Rh2 was found to have the potential to effectively alleviate liver fibrosis.

Identification of key genes associated with the progression of liver fibrosis to hepatocellular carcinoma based on iTRAQ proteomics and GEO database

INTRODUCTION AND OBJECTIVE

Liver fibrosis (LF) often leads to cirrhosis and even hepatocellular carcinoma (HCC), but the molecular mechanism remains unclear. The aims of the present study were to identify potential biomarkers for the progression of LF to HCC and explore the associated molecular mechanisms.

MATERIALS AND METHODS

The isobaric tags for relative and absolute quantitation (iTRAQ) was used to detect changes in the protein expression profiles of liver tissues and to screen the differentially expressed proteins (DEPs). The differentially expressed genes (DEGs) of LF rats and patients were screened by Gene Expression Database (GEO). Subsequently, the clinicopathological analysis of the overlapping genes in different pathological stages in HCC patients based on GEPIA database was conducted.

RESULTS

iTRAQ proteomic analysis revealed 689, 749 and 585 DEPs in the 6W, 8W and 12W groups, respectively. ALDH2, SLC27A5 and ASNS were not only the DEPs found in rats with LF with different stages but were also the DEGs related to the pathological stages and survival in patients with HCC.

CONCLUSIONS

ALDH2, SLC27A5 and ASNS were the potential biomarkers associated with the progression of LF to HCC.

The Role of H2S Regulating NLRP3 Inflammasome in Diabetes

Nucleotide-binding oligomeric domain (NOD)-like receptor protein 3 (NLRP3) is a recently discovered cytoplasmic multiprotein complex involved in inflammation. The NLRP3 inflammasome contains NLRP3, apoptosis-related specific protein (ASC) and precursor caspase-1. The NLRP3 inflammasome is involved in many diseases, including diabetes. H₂S is a harmful gas with a rotten egg smell. Recently, it has been identified as the third gas signal molecule after nitric oxide and carbon monoxide. It has many biological functions and plays an important role in many diseases, including diabetes. In recent years, it has been reported that H₂S regulation of the NLRP3 inflammasome contributes to a variety of diseases. However, the mechanism has not been fully understood. In this review, we summarized the recent role and mechanism of H₂S in regulating the NLRP3 inflammasome in diabetes, in order to provide a theoretical basis for future research.

miR-654-5p Contributes to the Activation and Proliferation of Hepatic Stellate Cells by Targeting RXRα

Liver fibrosis (LF) is a major disease that threatens human health. Hepatic stellate cells (HSCs) contribute directly to LF via extracellular matrix (ECM) secretion. Moreover, RXRα is an important nuclear receptor that plays a key regulatory role in HSC activation. Meanwhile, microRNAs (miRNAs) have been identified as significant regulators of LF development. In particular, miR-654-5p is involved in cellular migration and proliferation, and via bioinformatics analysis, has been identified as a potential factor that targets RXRα in humans and in mice. However, the precise relationship between miR-654-5p and RXRα in the context of LF, remains unknown and is the primary focus of the current study. To establish in vitro activated cell model human primary HSCs were cultured in vitro and LX-2 cells were stimulated with recombinant human TGF-β1. mRNA and protein levels of RXRα, miR-654-5p and fibrogenic genes were compared in quiescent and activated HSCs. Moreover, after transfected with miR-654-5p mimics, the expression changes of above related genes in LX-2 cells were estimated. Meanwhile, cell proliferation and apoptosis were detected in miR-654-5p overexpressed LX-2 cells. Simultaneously, the targeted binding between miR-654-5p and RXRα was verified in LX-2 cells. Carbon tetrachloride (CCl₄)-induced mouse model with liver fibrosis was use to research the role of the miR-654-5p in vitro. Our results show that miR-654-5p expression levels increased in activated human HSCs and TGFβ-treated LX-2 cells. Moreover, miR-654-5p mimics markedly promoted LX-2 cell proliferation while inhibiting their apoptosis. Accordingly, the expression levels of RXRα are decreased in activated HSCs and LX-2 cells. Additionally, dual-luciferase reporter assay results reveal direct targeting of RXRα by miR-654-5p. Similarly, in vivo miR-654-5p overexpression aggravates LF in mice that are intraperitoneally injected with CCl₄. Taken together, our findings elucidated a novel molecular mechanism with potential use for treatment of LF.

The Role of Endoplasmic Reticulum Stress and NLRP3 Inflammasome in Liver Disorders

The endoplasmic reticulum (ER) is a key organelle responsible for the synthesis, modification, folding and assembly of proteins; calcium storage; and lipid synthesis. When ER homeostatic balance is disrupted by a variety of physiological and pathological factors—such as glucose deficiency, environmental toxins, Ca²⁺ level changes, etc.—ER stress can be induced. Abnormal ER stress can be involved in many diseases. NOD-like receptor family pyrin domain-containing 3 (NLRP3), an intracellular receptor, can perceive internal and external stimuli. It binds to apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1 to assemble into a protein complex called the NLRP3 inflammasome. Evidence indicates that ER stress and the NLRP3 inflammasome participate in many pathological processes; however, the exact mechanism remains to be understood. In this review, we summarized the role of ER stress and the NLRP3 inflammasome in liver disorders and analyzed the mechanisms, to provide references for future related research.

Exosomes Regulate NLRP3 Inflammasome in Diseases

Emerging evidence has suggested the unique and critical role of exosomes as signal molecules vector in various diseases. Numerous researchers have been trying to identify how these exosomes function in immune progression, as this could promote their use as biomarkers for the disease process and potential promising diagnostic tools. NOD-like receptor (NLR) family, pyrin domain containing 3 (NLRP3), a tripartite protein, contains three functional domains a central nucleotide-binding and oligomerization domain (NACHT), an N-terminal pyrin domain (PYD), and a leucine-rich repeat domain (LRR). Of note, existing studies have identified exosome as a novel mediator of the NLRP3 inflammasome, which is critical in diseases progression. However, the actual mechanisms and clinical treatment related to exosomes and NLRP3 are still not fully understood. Herein, we presented an up-to-date review of exosomes and NLRP3 in diseases, outlining what is known about the role of exosomes in the activation of NLRP3 inflammasome and also highlighting areas of this topic that warrant further study.

STING signaling activation inhibits HBV replication and attenuates the severity of liver injury and HBV-induced fibrosis

The covalently closed circular DNA (cccDNA) of HBV plays a crucial role in viral persistence and is also a risk factor for developing HBV-induced diseases, including liver fibrosis. Stimulator of interferon genes (STING), a master regulator of DNA-mediated innate immune activation, is a potential therapeutic target for viral infection and virus-related diseases. In this study, agonist-induced STING signaling activation in macrophages was revealed to inhibit cccDNA-mediated transcription and HBV replication via epigenetic modification in hepatocytes. Notably, STING activation could efficiently attenuate the severity of liver injury and fibrosis in a chronic recombinant cccDNA (rcccDNA) mouse model, which is a proven suitable research platform for HBV-induced fibrosis. Mechanistically, STING-activated autophagic flux could suppress macrophage inflammasome activation, leading to the amelioration of liver injury and HBV-induced fibrosis. Overall, the activation of STING signaling could inhibit HBV replication through epigenetic suppression of cccDNA and alleviate HBV-induced liver fibrosis through the suppression of macrophage inflammasome activation by activating autophagic flux in a chronic HBV mouse model. This study suggests that targeting the STING signaling pathway may be an important therapeutic strategy to protect against persistent HBV replication and HBV-induced fibrosis.

Role of NLR family pyrin domain-containing 3 inflammasome in the activation of pancreatic stellate cells

NLRP3 inflammasome activation plays an important role in the development of pancreatic fibrosis. However, it is unclear whether the activation of the NLRP3 inflammasome is directly involved in the activation of Pancreatic stellate cells (PSCs). The aim of this study was to investigate the role and mechanism of the NLRP3 inflammasome in the activation of PSCs. In vivo, a rat model of chronic pancreatitis (CP) was induced by intravenous injection of dibutyltin dichloride (DBTC). In vitro, rat primary PSCs were isolated from pancreatic tissues and incubated with the NLRP3 inflammasome activator LPS, the NLRP3 inhibitor MCC950, or NLRP3 siRNA. The results showed that the expression of NLRP3, pro-Caspase-1, Caspase-1 and IL-18 was increased in the rat model of CP and during PSCs activation. LPS increased the protein levels of NLRP3, ASC, Caspase-1, IL-1β and IL-18 accompanied by the upregulation of α-SMA, Col I and FN expression. Moreover, MCC950 or NLPR3 siRNA decreased the expression of α-SMA, Col I, FN, TGF-β1 and p-Smad3. Furthermore, MCC950 reversed the LPS-induced upregulation of α-SMA, FN and Col Ⅰ expression in PSCs. This study revealed that the NLRP3 inflammasome is directly involved in the activation of PSCs in vivo and in vitro. Inhibiting NLRP3 suppresses the activation of PSCs through the TGF-β1/Smad3 pathway.

The role of autophagy in hepatic fibrosis

Hepatic fibrosis is a chronic liver injury process, and its continuous development can lead to cirrhosis, hepatic failure and even hepatocellular carcinoma (HCC). Autophagy has attracted much attention because of its controversial role in the course of hepatic fibrosis. In this review, we introduce the mechanism related to noncoding RNAs and some of the signaling pathways that promote or inhibit fibrosis by affecting autophagy. Finally, we list some targets related to autophagy that enable hepatic fibrosis therapy and forecast its prospect in hepatic fibrosis. This review will provide new ideas in diagnosing and treating hepatic fibrosis, which will be helpful to reduce the incidence of cirrhosis and its complications.

Cardiac fibrosis: Myofibroblast-mediated pathological regulation and drug delivery strategies

Cardiac fibrosis remains an unresolved problem in heart diseases. After initial injury, cardiac fibroblasts (CFs) are activated and subsequently differentiate into myofibroblasts (myoFbs) that are major mediator cells in the pathological remodeling. MyoFbs exhibit proliferative and secretive characteristics, and contribute to extracellular matrix (ECM) turnover, collagen deposition. The persistent functions of myoFbs lead to fibrotic scars and cardiac dysfunction. The anti-fibrotic treatment is hindered by the elusive mechanism of fibrosis and lack of specific targets on myoFbs. In this review, we will outline the progress of cardiac fibrosis and its contributions to the heart failure. We will also shed light on the role of myoFbs in the regulation of adverse remodeling. The communication between myoFbs and other cells that are involved in the heart injury and repair respectively will be reviewed in detail. Then, recently developed therapeutic strategies to treat fibrosis will be summarized such as i) chimeric antigen receptor T cell (CAR-T) therapy with an optimal target on myoFbs, ii) direct reprogramming from stem cells to quiescent CFs, iii) "off-target" small molecular drugs. The application of nano/micro technology will be discussed as well, which is involved in the construction of cell-based biomimic platforms and "pleiotropic" drug delivery systems.

Saikosaponin-d protects against liver fibrosis by regulating Estrogen receptor-β/NLRP3 inflammasome pathway

Liver fibrosis is the ultimate common pathway in most types of chronic liver damage characterized by imbalance of extracellular matrix degradation and synthesis. Saikosaponin-d (SSd) possesses anti-inflammatory and anti-liver fibrosis effects. However, the underlying mechanism of SSd in repressing hepatic stellate cells (HSCs) activation remains unclear. Here we found that SSd alleviated remarkably carbon tetrachloride (CCl4)-induced liver fibrosis, as evidenced by decreased collagen level and profibrotic markers (COl1a1 and α-smooth muscle actin (SMA)) expression. SSd repressed CCl4-induced NOD-like receptor family pyrin-domain-containng-3 (NLRP3) activation in fibrotic livers, as suggested by decreased level of NLRP3, IL-18, and IL-β. The primary HSCs of CCl4 mice exhibited a significant increase in profibrotic markers expression and NLRP3 activation, but SSd treatment reversed the effect. SSd also repressed TGF-β-induced profibrotic markers expression and NLRP3 activation in vitro. Mechanistically, TGF-β decreased the expression of Estrogen receptor-β (ERβ) in HSCs, whereas SSd treatment reversed the effect. ERβ inhibition enhanced NLRP3 activation in HSCs. More important, ERβ or NLRP3 inhibition destroyed partially the function of SSd on anti-liver fibrosis. In summary, the current data suggest that SSd prevents hepatic fibrosis through regulating ERβ/NLRP3 inflammasome pathway, and suggest SSd as a potential agent for treating liver fibrosis.

Pathophysiology and Treatment Options for Hepatic Fibrosis: Can It Be Completely Cured?

Hepatic fibrosis is a dynamic process that occurs as a wound healing response against liver injury. During fibrosis, crosstalk between parenchymal and non-parenchymal cells, activation of different immune cells and signaling pathways, as well as a release of several inflammatory mediators take place, resulting in inflammation. Excessive inflammation drives hepatic stellate cell (HSC) activation, which then encounters various morphological and functional changes before transforming into proliferative and extracellular matrix (ECM)-producing myofibroblasts. Finally, enormous ECM accumulation interferes with hepatic function and leads to liver failure. To overcome this condition, several therapeutic approaches have been developed to inhibit inflammatory responses, HSC proliferation and activation. Preclinical studies also suggest several targets for the development of anti-fibrotic therapies; however, very few advanced to clinical trials. The pathophysiology of hepatic fibrosis is extremely complex and requires comprehensive understanding to identify effective therapeutic targets; therefore, in this review, we focus on the various cellular and molecular mechanisms associated with the pathophysiology of hepatic fibrosis and discuss potential strategies to control or reverse the fibrosis.