PGE2 induces apoptosis of hepatic stellate cells and attenuates liver fibrosis in mice by downregulating miR-23a-5p and miR-28a-5p

The interactive role of microRNA and other non-coding RNA in hepatitis B (HBV) associated fibrogenesis

One of the outstanding features of chronic hepatitis B infection (CHB) is its strong association with liver fibrosis. CHB induced inflammation and injury trigger multiple biochemical and physical changes that include the promotion of a wide range of cytokines, chemokines and growth factors that activate hepatic stellate cells (HSCs) CHB induced activation of hepatic stellate cells (HSCs) is regarded as a central event in fibrogenesis to directly promote the synthesis of myofibroblasts and the expression of a range of materials to repair injured liver tissue. Fibrogenesis is modulated by the mainstream epigenetic machinery, as well as by non-coding RNA (ncRNA) that are often referred to as an ancillary epigenetic response to fine tune gene expression. Although extensive research has explained the regulatory role of ncRNA in liver fibrogenesis, most of this research relates to non-CHB etiologies. This review paper outlines the complex interactive regulatory role of microRNA (miRNA) and their interaction with long non-coding RNA (lncRNA), circular RNA (circRNA) and the mainstream epigenetic machinery in CHB induced liver fibrosis. The paper also illustrates some of the difficulties involved in translating candidate ncRNA into approved drugs or diagnostic tools. In conclusion, the important regulatory role of ncRNA in CHB induced liver fibrosis warrants further investigation to exploit their undoubted potential as diagnostic and therapeutic agents.

Time-course RNA sequencing reveals high similarity in mRNAome between hepatic stellate cells activated by agalactosyl IgG and TGF-β1

Previous studies have demonstrated the clinical relevance of aberrant serum immunoglobulin G (IgG) N-glycomic profiles in liver fibrosis and the pathogenic effects of agalactosyl IgG on activating hepatic stellate cells (HSCs). However, the dynamics of gene expression changes during HSC activation by agalactosyl IgG remain poorly understood. We performed RNA sequencing to analyze the mRNAome of human LX-2 HSCs at multiple time points after treatment with agalactosyl IgG and then compared these results with those obtained after normal IgG and transforming growth factor (TGF)-β1 treatments. Gene expression changes were significantly pronounced on day 5 and subsided by day 11 after HSC activation. A high degree of similarity in gene expression patterns between HSCs treated with agalactosyl IgG and TGF-β1 was observed, of which 1796 and 1785 differentially expressed genes (DEGs) were identified, respectively. Disease ontology analyses revealed that 114 and 105 DEGs in activated HSCs following agalactosyl IgG and TGF-β1 treatments, respectively, were linked to liver cirrhosis, hepatitis, fatty liver disease, hepatitis B, and alcoholic hepatitis, with CCL5 and FAS being the most commonly affected genes. DEGs associated with liver fibrosis or aforementioned liver diseases involved in gene annotation, physiological functions, and signaling pathways regarding secretion of cytokines and chemokines, expression of fibrosis-related growth factors and their receptors, modification of extracellular matrices, and regulation of cell viability in activated HSCs. In conclusion, this study characterized the dynamics of mRNAome and gene networks and identified the liver fibrosis-related DEGs during HSC activation by agalactosyl IgG and TGF-β1.

Administration of a combination of COX-2/TGF-β1 siRNAs induces hypertrophic scar fibroblast apoptosis through a TP53 mediated caspase pathway

Hypertrophic scar (HTS) formation is a pathological fibrotic skin disease, with no satisfactory treatments available currently. Inducing apoptosis of HTS-derived fibroblasts (HSFs) are becoming promising approaches. In this research, we aim to improve the technology with co-delivery COX-2 and TGF-β1 siRNAs and further investigate the underlying mechanism. Firstly, the HSFs were transfected with 1 µg/ml COX-2 and/or TGF-β1 siRNAs, and proved that the apoptosis of HSFs was greater induced by COX-2/TGF-β1 siRNAs than either COX-2 or TGF-β1 siRNA alone by flow cytometry. To investigate the impact of co-silencing TGF-β1 and COX-2 mRNA expression in vivo, we established HTSs model in rat tails. Our results confirmed that co-silencing of TGF-β1 and COX-2 mRNA expression could significantly alleviate the HTS formation in vivo. Furthermore, we explored the potential molecular mechanism and revealed that the protein levels of TP53, Bcl-2 and Caspase-3 were downregulated while Bax and Cleaved Caspase-3 were upregulated in the COX-2/TGF-β1 siRNA groups compared with HKP group. Taken together, our results demonstrated that simultaneous silencing of COX-2 and TGF-β1 expression by siRNAs induced HSF apoptosis through a TP53 mediated caspase pathway. Therefore, COX-2/TGF-β1 siRNAs might serve as a novel and effective therapeutic alternative for HTSs treatments.

Beneficial effects of hepatic cyclooxygenase-2 expression against cholestatic injury after common bile duct ligation in mice

BACKGROUND AND AIMS

Cyclooxygenase-2 (COX-2) is involved in different liver diseases, but little is known about the significance of COX-2 in cholestatic injury. This study was designed to elucidate the role of COX-2 expression in hepatocytes during the pathogenesis of obstructive cholestasis.

METHODS

We used genetically modified mice constitutively expressing human COX-2 in hepatocytes. Transgenic mice (hCOX-2-Tg) and their wild-type (Wt) littermates were either subjected to a mid-abdominal laparotomy or common bile duct ligation (BDL) for 2 or 5 days. Then, we explored the mechanisms underlying the role of COX-2 and its derived prostaglandins in liver function, and the synthesis and excretion of bile acids (BA) in response to cholestatic liver injury.

RESULTS

After BDL, hCOX-2-Tg mice showed lower grades of hepatic necrosis and inflammation than Wt mice, in part by a reduced hepatic neutrophil recruitment associated with lower mRNA levels of pro-inflammatory cytokines. Furthermore, hCOX-2-Tg mice displayed a differential metabolic pattern of BA synthesis that led to an improved clearance after BDL-induced accumulation. In addition, an enhanced response to the BDL-induced oxidative stress and hepatic apoptosis was observed. In vitro experiments using hepatic cells that stably express hCOX-2 confirmed the cytoprotective role of prostaglandin E2 against BA toxicity.

CONCLUSIONS

Taken together, our data indicate that constitutive expression of COX-2 in hepatocytes ameliorates cholestatic liver injury in mice by reducing inflammation and cell damage and by modulating BA metabolism, pointing to a role for COX-2 as a defensive response against cholestasis-derived BA accumulation and injury.

Noncoding RNA-Mediated Epigenetic Regulation in Hepatic Stellate Cells of Liver Fibrosis

Liver fibrosis is a significant contributor to liver-related disease mortality on a global scale. Despite this, there remains a dearth of effective therapeutic interventions capable of reversing this condition. Consequently, it is imperative that we gain a comprehensive understanding of the underlying mechanisms driving liver fibrosis. In this regard, the activation of hepatic stellate cells (HSCs) is recognized as a pivotal factor in the development and progression of liver fibrosis. The role of noncoding RNAs (ncRNAs) in epigenetic regulation of HSCs transdifferentiation into myofibroblasts has been established, providing new insights into gene expression changes during HSCs activation. NcRNAs play a crucial role in mediating the epigenetics of HSCs, serving as novel regulators in the pathogenesis of liver fibrosis. As research on epigenetics expands, the connection between ncRNAs involved in HSCs activation and epigenetic mechanisms becomes more evident. These changes in gene regulation have attracted considerable attention from researchers in the field. Furthermore, epigenetics has contributed valuable insights to drug discovery and the identification of therapeutic targets for individuals suffering from liver fibrosis and cirrhosis. As such, this review offers a thorough discussion on the role of ncRNAs in the HSCs activation of liver fibrosis.

In silico screening and in vivo experimental validation of 15-PGDH inhibitors from traditional Chinese medicine promoting liver regeneration

The enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH), which acts as a negative regulator of prostaglandin E2 (PGE2) levels and activity, represents a promising pharmacological target for promoting liver regeneration. In this study, we collected data on 15-PGDH homologous family proteins, their inhibitors, and traditional Chinese medicine (TCM) compounds. Leveraging machine learning and molecular docking techniques, we constructed a prediction model for virtual screening of 15-PGDH inhibitors from TCM compound library and successfully screened genistein as a potential 15-PGDH inhibitor. Through further validation, it was discovered that genistein considerably enhances liver regeneration by inhibiting 15-PGDH, resulting in a significant increase in the PGE2 level. Genistein's effectiveness suggests its potential as a novel therapeutic agent for liver diseases, highlighting this study's contribution to expanding the clinical applications of TCM.

Efficacy and safety of Piwei Peiyuan Prescription in the treatment of chronic atrophic gastritis: A multicenter, double-blind, double-simulated, randomized, controlled clinical trial

The incidence of chronic atrophic gastritis (CAG) is on the rise due to the growing pressure in modern social life, increasing bad living habits and emotional disorders (such as anxiety and depression), and the aging of the population. Of note, digestive system diseases are the dominant diseases in the field of traditional Chinese medicine (TCM). Therefore, this study evaluated the efficacy and safety of Piwei Peiyuan Prescription, a TCM prescription, in the treatment of CAG through a multicenter, double-blind, randomized, controlled design. This research was organized by the Second Affiliated Hospital of Anhui University of TCM and simultaneously performed in 6 centers. A total of 120 CAG patients were included and randomized into 2 groups: group A (treatment with Piwei Peiyuan granules plus Weifuchun Simulant) and Group B (treatment with Weifuchun Tablets plus Piwei Peiyuan Simulant). These 2 groups were compared in terms of gastroscopy scores, TCM syndrome scores, and serological indicators at baseline and within 12 weeks after treatment. According to endoscopic biopsy for pathological observation, atrophy (2.56 ± 1.08 vs 3.00 ± 1.00, P = .028) and intestinal epithelial hyperplasia (1.00 ± 1.43 vs 1.69 ± 1.80, P = .043) scores were lower in group A than in group B. For the more, group A had higher effective rates for inflammation, atrophy, and intestinal metaplasia (IM) in various regions of the stomach, especially for atrophy/IM of the gastric angle (64%, P = .034) and atrophy/IM of the lesser curvature of gastric antrum (63%, P = .042) than group B. According to TCM syndrome scores, Piwei Peiyuan Prescription improved the scores of gastric distension (2.30 ± 1.13 vs 2.80 ± 0.99, P = .022), preference for warmth and pressure (1.44 ± 1.06 vs 1.36 ± 1.10, P = .041), and poor appetite and indigestion (0.78 ± 0.66 vs 1.32 ± 0.72, P = .018). GAS, MTL, and PGE2 expression was significantly elevated after treatment with Piwei Peiyuan Prescription (P < .001). Piwei Peiyuan Prescription is effective for CAG treatment with high safety.

Crosstalk between P2Y receptors and cyclooxygenase activity in inflammation and tissue repair

The role of extracellular nucleotides as modulators of inflammation and cell stress is well established. One of the main actions of these molecules is mediated by the activation of purinergic receptors (P2) of the plasma membrane. P2 receptors can be classified according to two different structural families: P2X ionotropic ion channel receptors, and P2Y metabotropic G protein-coupled receptors. During inflammation, damaged cells release nucleotides and purinergic signaling occurs along the temporal pattern of the synthesis of pro-inflammatory and pro-resolving mediators by myeloid and lymphoid cells. In macrophages under pro-inflammatory conditions, the expression and activity of cyclooxygenase 2 significantly increases and enhances the circulating levels of prostaglandin E2 (PGE2), which exerts its effects both through specific plasma membrane receptors (EP1-EP4) and by activation of intracellular targets. Here we review the mechanisms involved in the crosstalk between PGE2 and P2Y receptors on macrophages, which is dependent on several isoforms of protein kinase C and protein kinase D1. Due to this crosstalk, a P2Y-dependent increase in calcium is blunted by PGE2 whereas, under these conditions, macrophages exhibit reduced migratory capacity along with enhanced phagocytosis, which contributes to the modulation of the inflammatory response and tissue repair.

Bioactive signalling lipids as drivers of chronic liver diseases

Lipids are important in multiple cellular functions, with most having structural or energy storage roles. However, a small fraction of lipids exert bioactive roles through binding to G protein-coupled receptors and induce a plethora of processes including cell proliferation, differentiation, growth, migration, apoptosis, senescence and survival. Bioactive signalling lipids are potent modulators of metabolism and energy homeostasis, inflammation, tissue repair and malignant transformation. All these events are involved in the initiation and progression of chronic liver diseases. In this review, we focus specifically on the roles of bioactive lipids derived from phospholipids (lyso-phospholipids) and poly-unsaturated fatty acids (eicosanoids, pro-resolving lipid mediators and endocannabinoids) in prevalent chronic liver diseases (alcohol-associated liver disease, non-alcoholic fatty liver disease, viral hepatitis and hepatocellular carcinoma). We discuss the balance between pathogenic and beneficial bioactive lipids as well as potential therapeutic targets related to the agonism or antagonism of their receptors.

Qijia rougan formula ameliorates ECM deposition in hepatic fibrosis by regulating the JAK1/STAT6-microRNA-23a feedback loop in macrophage M2 polarization

Hepatic fibrosis is the critical pathological stage in the progression of chronic liver disease to cirrhosis and hepatocellular carcinoma (HCC). However, no approved anti-hepatic fibrosis drugs are available currently. Qijia Rougan Formula (QRF) is a traditional Chinese medicine (TCM) with significant clinical efficacy on hepatic fibrosis. It was derived from Sanjiasan, a famous decoction documented in the Book of Treatise on the Pestilence in the Ming Dynasty of China. However, the underlying regulatory mechanisms remain elusive. This study further confirmed the therapeutic effects of QRF on hepatic fibrosis and dissected its underlying molecular mechanisms from the perspective of macrophage M2 polarization, one of the critical events in hepatic fibrosis. Experimentally, QRF significantly improved extracellular matrix (ECM) deposition and fibrosis in the liver of model rats. QRF diminished the proportion of M2 macrophages, decreased the levels of TGF-β, PDGFB and IL-10, and regulated the expression of p-JAK1, p-STAT6, JAK1 and microRNA-23a both in vitro and in vivo. Collectively, it was confirmed that QRF effectively improves liver function and hepatocyte damage, and reduces ECM deposition. QRF ameliorates hepatic fibrosis by regulating JAK1/STAT6-microRNA-23a negative feedback loop to inhibit macrophage M2 polarization and thus reduce ECM deposition. Our study illustrates the potential of QRF for hepatic fibrosis therapy, suggesting that QRF is a promising anti-hepatic fibrosis drug candidate.

GAS5 protects against nonalcoholic fatty liver disease via miR-28a-5p/MARCH7/NLRP3 axis-mediated pyroptosis

Nonalcoholic fatty liver disease (NAFLD) is characterised by hepatic steatosis, inflammation, and insulin resistance. The role of long noncoding RNA (lncRNA)-regulated pyroptosis in NAFLD development remains largely unknown. This study aimed to investigate whether NAFLD development is controlled by lncRNA growth-arrest specific transcript 5 (GAS5)/miR-28a-5p/membrane associated ring-CH-type finger 7 (MARCH7)-mediated pyroptosis using in vivo and in vitro models. First, GAS5 expression was decreased but miR-28a-5p expression was increased in the livers of NAFLD patients, high-fat diet (HFD)-fed mice and leptin-deficient obese (Ob/Ob) mice. Furthermore, GAS5 suppressed while miR-28a-5p promoted NAFLD development, and overexpression of miR-28a-5p reversed the GAS5 overexpression-induced attenuation of NAFLD. Mechanistically, GAS5 served as a sponge of miR-28a-5p, and miR-28a-5p enhanced pyroptosis by targeting the 3' untranslated region (UTR) of the E3 ligase MARCH7 during NAFLD development. MARCH7 interacted with the NOD-like receptor protein 3 (NLRP3) protein, resulting in proteasomal degradation of NLRP3 to inhibit pyroptosis. As expected, MARCH7 knockdown abolished the miR-28a-5p knockdown-induced inhibition of NAFLD development, and the ubiquitin E3 ligase-inactive mutant (W589A/I556A) of MARCH7 failed to inhibit NAFLD development. In conclusion, GAS5 protected against NAFLD development by binding to miR-28a-5p, miR-28a-5p promoted NAFLD development by targeting MARCH7, and MARCH7 ameliorated NAFLD by suppressing NLRP3-mediated pyroptosis. The GAS5/miR-28a-5p/MARCH7/NLRP3 axis plays an important role in NAFLD progression, and it might be a biomarker for NAFLD.

Reviewing the Regulators of COL1A1

The collagen family contains 28 proteins, predominantly expressed in the extracellular matrix (ECM) and characterized by a triple-helix structure. Collagens undergo several maturation steps, including post-translational modifications (PTMs) and cross-linking. These proteins are associated with multiple diseases, the most pronounced of which are fibrosis and bone diseases. This review focuses on the most abundant ECM protein highly implicated in disease, type I collagen (collagen I), in particular on its predominant chain collagen type I alpha 1 (COLα1 (I)). An overview of the regulators of COLα1 (I) and COLα1 (I) interactors is presented. Manuscripts were retrieved searching PubMed, using specific keywords related to COLα1 (I). COL1A1 regulators at the epigenetic, transcriptional, post-transcriptional and post-translational levels include DNA Methyl Transferases (DNMTs), Tumour Growth Factor β (TGFβ), Terminal Nucleotidyltransferase 5A (TENT5A) and Bone Morphogenic Protein 1 (BMP1), respectively. COLα1 (I) interacts with a variety of cell receptors including integrinβ, Endo180 and Discoidin Domain Receptors (DDRs). Collectively, even though multiple factors have been identified in association to COLα1 (I) function, the implicated pathways frequently remain unclear, underscoring the need for a more spherical analysis considering all molecular levels simultaneously.

Fatty Acids and Eicosanoids Change during High-Fiber Diet in NAFLD Patients-Randomized Control Trials (RCT)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a wide spectrum condition characterized by excessive liver fat accumulation in people who do not abuse alcohol. There is no effective medical treatment for NAFLD; therefore, most important recommendations to reduce liver steatosis are diet and lifestyle, including proper physical activity. The aim of our study was to analyze the fatty acids and eicosanoids changes in the serum of patients who consumed high-fiber rolls for 8 weeks.

MATERIALS AND METHODS

The group of 28 Caucasian participants was randomly divided into two groups, those who received 24 g of fiber/day-from 2 buns of 12 g each (n = 14), and those who received 12 g of fiber/day-from 2 buns of 6 g (n = 14). At the beginning and on the last visit of the 8-week intervention, all patients underwent NAFLD evaluation, biochemical parameter measurements, and fatty acids and eicosanoids evaluation.

RESULTS

Patients who received 12 g of fiber had significantly reduced liver steatosis and body mass index. In the group who received 24 g of fiber/day, we observed a trend to liver steatosis reduction (p = 0.07) and significant decrease in aspartate aminotransferase (p = 0.03) and total cholesterol (p = 0.03). All changes in fatty acid and eicosanoids profile were similar. Fatty acids analysis revealed that extra fiber intake was associated with a significant increase in monounsaturated fatty acids and decrease in saturated fatty acids. Moreover, both groups showed increased concentration of gamma linoleic acid and docosahexaenoic acid. We also observed reduction in prostaglandin E₂.

CONCLUSIONS

Our study revealed that a high amount of fiber in the diet is associated with a reduction in fatty liver, although this effect was more pronounced in patients in the lower fiber group. However, regardless of the amount of fiber consumed, we observed significant changes in the profile of FAs, which may reflect the positive changes in the lipids liver metabolism. Regardless of the amount of fiber consumed, patients decreased the amount of PGE₂, which may indicate the lack of disease progression associated with the development of inflammation.

ACBP/DBI protein neutralization confers autophagy-dependent organ protection through inhibition of cell loss, inflammation, and fibrosis

Acyl-coenzyme A (CoA)-binding protein (ACBP), also known as diazepam-binding inhibitor (DBI), is an extracellular feedback regulator of autophagy. Here, we report that injection of a monoclonal antibody neutralizing ACBP/DBI (α-DBI) protects the murine liver against ischemia/reperfusion damage, intoxication by acetaminophen and concanavalin A, and nonalcoholic steatohepatitis caused by methionine/choline-deficient diet as well as against liver fibrosis induced by bile duct ligation or carbon tetrachloride. α-DBI downregulated proinflammatory and profibrotic genes and upregulated antioxidant defenses and fatty acid oxidation in the liver. The hepatoprotective effects of α-DBI were mimicked by the induction of ACBP/DBI-specific autoantibodies, an inducible Acbp/Dbi knockout or a constitutive Gabrg2^F77I mutation that abolishes ACBP/DBI binding to the GABA_A receptor. Liver-protective α-DBI effects were lost when autophagy was pharmacologically blocked or genetically inhibited by knockout of Atg4b. Of note, α-DBI also reduced myocardium infarction and lung fibrosis, supporting the contention that it mediates broad organ-protective effects against multiple insults.

Sex-specific analysis of microRNA profiles in HBV-associated cirrhosis by small RNA-sequencing

Liver cirrhosis represents an advanced stage of chronic liver disease and is associated with significant morbidity, mortality, and risk of cancer development. While sex disparity of liver diseases has been observed, understanding at a genetic level awaits more thorough investigation. In this study, we performed a sex-specific analysis of the microRNA (miR) profiles in hepatitis B virus (HBV)-associated cirrhosis by small RNA-sequencing using clinical tissue samples. Potential associated signaling pathways, downstream gene targets, and upstream regulators were highlighted by computational prediction analyses based on the differentially expressed miRs (DEmiRs). From our results, deregulation of miRs in cirrhosis showed a marked difference between males and females by the degree and pattern. Sixty-five (64 up-regulated, 1 down-regulated) and 12 (6 up-regulated, 6 down-regulated) DEmiRs were found in males and females, respectively, when compared with their respective control group. A number of DEmiRs were only observed in one sex but not the other. In addition, 26 DEmiRs were identified between cirrhosis female and cirrhosis male groups. Fatty acid biosynthesis pathway, extracellular matrix-receptor interaction, p53 signaling, Hippo signaling, tumor necrosis factor signaling, the forkhead box O signaling, as well as gene targets ribosomal protein S27 like, methyl CpG binding protein 2, and estrogen receptor 1, may contribute to the pathogenesis and biological behavior of cirrhosis in a sex-specific manner. Analysis of the Cancer Genome Atlas data set suggested a role of sex-specific DEmiRs in multistep hepatocarcinogenesis. Conclusion: Our findings illustrate that miR profiles in HBV-associated cirrhosis are distinct between the males and females and suggest a potential role of sex-specific biomarkers and molecular mechanisms in disease development and progression.

Human Allogeneic Liver-Derived Progenitor Cells Significantly Improve NAFLD Activity Score and Fibrosis in Late-Stage NASH Animal Model

Accumulated experimental and clinical evidence supports the development of human allogeneic liver-derived progenitor cells (HALPCs) to treat fibro-inflammatory liver diseases. The aim of the present study was to evaluate their therapeutic effect in a non-alcoholic steatohepatitis (NASH)-STAM mouse model. The immune signaling characteristics of HALPCs were first assessed in vitro. Upon inflammation treatment, HALPCs secreted large amounts of potent bioactive prostaglandin E2 and indoleamine 2,3-dioxygenase, which significantly reduced CD4⁺ T-lymphocyte proliferation and secretion of proinflammatory cytokines. In vivo, HALPCs were intravenously administered as single or triple shots (of a dose of 12.5 × 10⁶ cells/kg BW) in STAM mice. Transplantation of HALPCs was associated with a significant decrease in the NAFLD activity score at an early stage and in both inflammation and hepatocyte ballooning scores in late-stage NASH. Sirius red staining analyses revealed decreased collagen deposition in the pericentral region at both stages of NASH. Altogether, these findings showed the anti-inflammatory and anti-fibrotic features of HALPCs in an in vivo NASH model, which suggests their potential to reverse the progression of this chronic fibro-inflammatory disease.

Oxidative stress-mediated mitochondrial fission promotes hepatic stellate cell activation via stimulating oxidative phosphorylation

Previous studies have demonstrated dysregulated mitochondrial dynamics in fibrotic livers and hepatocytes. Little is currently known about how mitochondrial dynamics are involved, nor is it clear how mitochondrial dynamics participate in hepatic stellate cell (HSC) activation. In the present study, we investigated the role of mitochondrial dynamics in HSC activation and the underlying mechanisms. We verified that mitochondrial fission was enhanced in human and mouse fibrotic livers and active HSCs. Moreover, increased mitochondrial fission driven by fis1 overexpression could promote HSC activation. Inhibiting mitochondrial fission using mitochondrial fission inhibitor-1 (Mdivi-1) could inhibit activation and induce apoptosis of active HSCs, indicating that increased mitochondrial fission is essential for HSC activation. Mdivi-1 treatment also induced apoptosis in active HSCs in vivo and thus ameliorated CCl₄-induced liver fibrosis. We also found that oxidative phosphorylation (OxPhos) was increased in active HSCs, and OxPhos inhibitors inhibited activation and induced apoptosis in active HSCs. Moreover, increasing mitochondrial fission upregulated OxPhos, while inhibiting mitochondrial fission downregulated OxPhos, suggesting that mitochondrial fission stimulates OxPhos during HSC activation. Next, we found that inhibition of oxidative stress using mitoquinone mesylate (mitoQ) and Tempol inhibited mitochondrial fission and OxPhos and induced apoptosis in active HSCs, suggesting that oxidative stress contributes to excessive mitochondrial fission during HSC activation. In conclusion, our study revealed that oxidative stress contributes to enhanced mitochondrial fission, which triggers OxPhos during HSC activation. Importantly, inhibiting mitochondrial fission has huge prospects for alleviating liver fibrosis by eliminating active HSCs.

The miR-23-27-24 cluster: an emerging target in NAFLD pathogenesis

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing globally, being the most widespread form of chronic liver disease in the west. NAFLD includes a variety of disease states, the mildest being non-alcoholic fatty liver that gradually progresses to non-alcoholic steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Small non-coding single-stranded microRNAs (miRNAs) regulate gene expression at the miRNA or translational level. Numerous miRNAs have been shown to promote NAFLD pathogenesis and progression through increasing lipid accumulation, oxidative stress, mitochondrial damage, and inflammation. The miR-23-27-24 clusters, composed of miR-23a-27a-24-2 and miR-23b-27b-24-1, have been implicated in various biological processes as well as many diseases. Herein, we review the current knowledge on miR-27, miR-24, and miR-23 in NAFLD pathogenesis and discuss their potential significance in NAFLD diagnosis and therapy.

Renal subcapsular delivery of PGE2 promotes kidney repair by activating endogenous Sox9+ stem cells

Prostaglandin E₂ (PGE₂) has recently been recognized to play a role in immune regulation and tissue regeneration. However, the short half-life of PGE₂ limits its clinical application. Improving the delivery of PGE₂ specifically to the target organ with a prolonged release method is highly desirable. Taking advantage of the adequate space and proximity of the renal parenchyma, renal subcapsular delivery allows minimally invasive and effective delivery to the entire kidney. Here, we report that by covalently cross-linking it to a collagen matrix, PGE₂ exhibits an adequate long-term presence in the kidney with extensive intraparenchymal penetration through renal subcapsular delivery and significantly improves kidney function. Sox9 cell lineage tracing with intravital microscopy revealed that PGE₂ could activate the endogenous renal progenitor Sox9⁺ cells through the Yap signaling pathway. Our results highlight the prospects of utilizing renal subcapsular-based drug delivery and facilitate new applications of PGE₂-releasing matrices for regenerative therapy.

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PGE₂ exhibits an adequate long-term release by being covalently cross-linked to collagen

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The renal subcapsular space serves as a reservoir for the delivery of PGE₂

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Sox9⁺ renal progenitor cells can be lineage traced intravitally by microscopy

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PGE₂ activates the endogenous renal progenitor Sox9⁺ cells through the YAP pathway

Embryonal erythropoiesis and aging exploit ferroptosis

Ferroptosis is a form of regulated cell necrosis, as a consequence of Fe(II)-dependent lipid peroxidation. Although ferroptosis has been linked to cancer cell death, neurodegeneration and reperfusion injury, physiological roles of ferroptosis have not been elucidated to date mostly due to the lack of appropriate methodologies. Here, we show that 4-hydroxy-2-nonenal (HNE)-modified proteins detected by a HNEJ-1 mouse monoclonal antibody is a robust immunohistochemical technology to locate ferroptosis in tissues in combination with morphological nuclear information, based on various models of ferroptosis, including erastin-induced cysteine-deprivation, conditional Gpx4 knockout and Fe(II)-dependent renal tubular injury, as well as other types of regulated cell death. Specificity of HNEJ-1 with ferroptosis was endorsed by non-selective identification of HNE-modified proteins in an Fe(II)-dependent renal tubular injury model. We further comprehensively searched for signs of ferroptosis in different developmental stages of Fischer-344 rats from E9.5-2.5 years of age. We observed that there was a significant age-dependent increase in ferroptosis in the kidney, spleen, liver, ovary, uterus, cerebellum and bone marrow, which was accompanied by iron accumulation. Not only phagocytic cells but also parenchymal cells were affected. Epidermal ferroptosis in ageing SAMP8 mice was significantly promoted by high-fat or carbohydrate-restricted diets. During embryogenesis of Fischer-344 rats, we found ferroptosis in nucleated erythrocytes at E13.5, which disappeared in enucleated erythrocytes at E18.5. Administration of a ferroptosis inhibitor, liproxstatin-1, significantly delayed erythrocyte enucleation. Therefore, our results demonstrate for the first time the involvement of ferroptosis in physiological processes, such as embryonic erythropoiesis and aging, suggesting the evolutionally acquired mechanism and the inevitable side effects, respectively.

Novel Nano-Based Drug Delivery Systems Targeting Hepatic Stellate Cells in the Fibrotic Liver

Hepatic stellate cells (HSCs) exist in the liver’s perisinusoidal space, are phenotypically activated, and acquire myofibroblast-like phenotype. This phenotypic transformation is accountable for the accumulation and production of various extracellular matrix (ECM) proteins, involving different fibril-forming collagens in the perisinusoidal space, producing altered hepatic function and portal hypertension and increased vascular resistance, fibrosis, cirrhosis, and hepatocellular carcinoma. The activated HSCs/myofibroblasts are principal collagen-producing cells in the damaged liver. Therefore, fibrosis treatments are often targeting HSCs. HSCs store most of the total body’s retinol in their cytoplasm, and hence, antifibrotic nanomedicines are often targeted with vitamin A decoration. Vitamin A-decorated nanomedicines with siRNAs for transforming growth factor-beta, collagen, and connective tissue growth factors target to inhibit fibrogenesis and the ECM-associated gene expressions, leading to fibrosis regression. Similarly, a variety of miRNAs play pro- and antifibrotic function. In the fibrotic liver, the profibrotic miRNAs are targeted with their respective antagomir and the antifibrotic miRNAs are targeted with their respective agomirs along with HSC-specific nanodecoration. These miRNA treatments reduce fibrogenesis by downregulation of ECM-related gene expressions. However, liver fibrosis is caused by the upregulation of a different type of profibrotic signaling pathways associated with ECM accumulation in the fibrotic liver. Therefore, specific gene silencing by siRNAs or targeting particularly miRNA may also not effectively reduce fibrosis to a greater extent. However, nanodecoration of a drug is useful to deliver drugs into activated HSCs in the injured liver. Therefore, the aim of this review is to focus on targeted drug delivery towards activated HSCs in the persistently damaged liver.

Celecoxib reduces hepatic vascular resistance in portal hypertension by amelioration of endothelial oxidative stress

The balance between endothelial nitric oxide (NO) synthase (eNOS) activation and production of reactive oxygen species (ROS) is very important for NO homeostasis in liver sinusoidal endothelial cells (LSECs). Overexpression of cyclooxygenase‐2 (COX‐2), a major intravascular source of ROS production, has been observed in LSECs of cirrhotic liver. However, the links between low NO bioavailability and COX‐2 overexpression in LSECs are unknown. This study has confirmed the link between low NO bioavailability and COX‐2 overexpression by COX‐2‐dependent PGE2‐EP2‐ERK1/2‐NOX1/NOX4 signalling pathway in LSECs in vivo and in vitro. In addition, the regulation of COX‐2‐independent LKB1‐AMPK‐NRF2‐HO‐1 signalling pathway on NO homeostasis in LSECs was also elucidated. The combinative effects of celecoxib on diminishment of ROS via COX‐2‐dependent and COX‐2‐independent signalling pathways greatly decreased NO scavenging. As a result, LSECs capillarisation was reduced, and endothelial dysfunction was corrected. Furthermore, portal hypertension of cirrhotic liver was ameliorated with substantial decreasing hepatic vascular resistance and great increase of portal blood flow. With the advance understanding of the mechanisms of LSECs protection, celecoxib may serve as a potential therapeutic candidate for patients with cirrhotic portal hypertension.

Role of prostaglandin E2 in tissue repair and regeneration

Tissue regeneration following injury from disease or medical treatment still represents a challenge in regeneration medicine. Prostaglandin E2 (PGE2), which involves diverse physiological processes via E-type prostanoid (EP) receptor family, favors the regeneration of various organ systems following injury for its capabilities such as activation of endogenous stem cells, immune regulation, and angiogenesis. Understanding how PGE2 modulates tissue regeneration and then exploring how to elevate the regenerative efficiency of PGE2 will provide key insights into the tissue repair and regeneration processes by PGE2. In this review, we summarized the application of PGE2 to guide the regeneration of different tissues, including skin, heart, liver, kidney, intestine, bone, skeletal muscle, and hematopoietic stem cell regeneration. Moreover, we introduced PGE2-based therapeutic strategies to accelerate the recovery of impaired tissue or organs, including 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibitors boosting endogenous PGE2 levels and biomaterial scaffolds to control PGE2 release.

MicroRNA-23a-5p Is Involved in the Regulation of Lipopolysaccharide-Induced Acute Lung Injury by Targeting HSP20/ASK1

Inflammation and oxidative stress contribute to the progression of acute lung injury (ALI). MicroRNA-23a-5p (miR-23a-5p) has been reported to regulate inflammation and oxidative stress; however, its role in ALI is still poorly elucidated. Mice were intravenously treated with the miR-23a-5p antagomir, agomir, or the negative controls for 3 consecutive days and then received a single intratracheal injection of lipopolysaccharide (LPS, 5 mg/kg) to induce ALI. Pulmonary function, bronchoalveolar lavage fluids (BALFs), arterial blood gas, and molecular biomarkers associated with inflammation and oxidative stress were analyzed. In addition, murine peritoneal macrophages were isolated and treated with LPS to verify the role of miR-23a-5p in vitro. We detected an elevation of miR-23a-5p expression in the lungs from ALI mice. The miR-23a-5p antagomir was prevented, whereas the miR-23a-5p agomir aggravated inflammation, oxidative stress, lung tissue injury, and pulmonary dysfunction in LPS-treated mice. Besides, the miR-23a-5p antagomir also reduced the productions of proinflammatory cytokines and free radicals in LPS-treated primary macrophages, which were further augmented in cells following the miR-23a-5p agomir treatment. Additional findings demonstrated that the miR-23a-5p agomir exacerbated LPS-induced ALI via activating apoptosis signal-regulating kinase 1 (ASK1), and that pharmacological or genetic inhibition of ASK1 significantly repressed the deleterious effects of the miR-23a-5p agomir. Moreover, we proved that the miR-23a-5p agomir activated ASK1 via directly reducing heat shock protein 20 (HSP20) expression. miR-23a-5p is involved in the regulation of LPS-induced inflammation, oxidative stress, lung tissue injury, and pulmonary dysfunction by targeting HSP20/ASK1, and it is a valuable therapeutic candidate for the treatment of ALI.

Role of eicosanoids in liver repair, regeneration and cancer

Eicosanoids are lipid signaling molecules derived from the oxidation of ω-6 fatty acids, usually arachidonic acid. There are three major pathways, including the cyclooxygenase (COX), lipoxygenase (LOX), and P450 cytochrome epoxygenase (CYP) pathway. Prostanoids, which include prostaglandins (PG) and thromboxanes (Tx), are formed via the COX pathway, leukotrienes (LT) and lipoxins (LX) by the action of 5-LOX, and hydroxyeicosatetraenoic acids (HETEs) and epoxyeicosatrienoic acids (EETs) by CYP. Although eicosanoids are usually associated with pro-inflammatory responses, non-classic eicosanoids, as LX, have anti-inflammatory and pro-resolving properties. Eicosanoids like PGE₂, LTB₄ and EETs have been involved in promoting liver regeneration after partial hepatectomy. PGE₂ and LTB₄ have also been reported to participate in the regenerative phase after ischemia and reperfusion (I/R), while cysteinyl leukotrienes (Cys-LT) contribute to the inflammatory process associated with I/R and are also involved in liver fibrosis and cirrhosis. However, LX, another product of 5-LOX, have the opposite effect, acting as pro-resolving mediators in these pathologies. In liver cancer, most studies show that eicosanoids, with the exception of LX, promote the proliferation of hepatocellular carcinoma cells and favor metastasis. This review summarizes the synthesis of different eicosanoids in the liver and discusses key findings from basic research linking eicosanoids to liver repair, regeneration and cancer and the impact of targeting eicosanoid cascade. In addition, studies in patients are presented that explore the potential use of eicosanoids as biomarkers and show correlations between eicosanoid production and the course and prognosis of liver disease.

LINC00265 maintains hepatocyte proliferation during liver regeneration by targeting miRNA-28-5p

Long noncoding RNAs have been implicated in many biological processes, but their roles in liver regeneration still need to be illustrated. Therefore, we aimed to investigate the role of LINC00265 as a pivotal regulator of hepatocyte proliferation during liver regeneration. It was found that LINC00265 is significantly upregulated in rat liver tissues at various time points after 2/3 liver resection. LINC00265 knockdown inhibited hepatocyte proliferation, induced cell apoptosis and led to G2/M phase cell cycle arrestment. In rats subjected to surgery, LINC00265 knockdown decreased liver/body weight ratio, attenuated improvement from liver damage and reduced Ki67 and PCNA expression. Luciferase reporter assays confirmed that miR-28-5p was a direct target of LINC00265, and inhibition of miR-28-5p abolished the effect of LINC00265 knockdown. In summary, LINC00265 might maintain hepatocyte proliferation by targeting miR-28-5p during liver regeneration and should be considered as a promising therapeutic option for hepatocyte regeneration after liver resection.

Mesenchymal stem cell-derived extracellular vesicles as probable triggers of radiation-induced heart disease

BACKGROUND

Radiation-induced heart disease has been reported, but the underlying mechanisms remain unclear. Mesenchymal stem cells (MSCs), also residing in the heart, are highly susceptible to radiation. We examined the hypothesis that the altered secretion of extracellular vesicles (EVs) from MSCs is the trigger of radiation-induced heart disease.

METHODS

By exposing human placental tissue-derived MSCs to 5 Gy γ-rays, we then isolated EVs from the culture medium 48 h later and evaluated the changes in quantity and quality of EVs from MSCs after radiation exposure. The biological effects of EVs from irradiated MSCs on HUVECs and H9c2 cells were also examined.

RESULTS

Although the amount and size distribution of EVs did not differ between the nonirradiated and irradiated MSCs, miRNA sequences indicated many upregulated or downregulated miRNAs in irradiated MSCs EVs. In vitro experiments using HUVEC and H9c2 cells showed that irradiated MSC-EVs decreased cell proliferation (P < 0.01), but increased cell apoptosis and DNA damage. Moreover, irradiated MSC-EVs impaired the HUVEC tube formation and induced calcium overload in H9c2 cells.

CONCLUSIONS

EVs released from irradiated MSCs show altered miRNA profiles and harmful effects on heart cells, which provides new insight into the mechanism of radiation-related heart disease risks.

Inhibition of cyclooxygenase-2 enhanced intestinal epithelial homeostasis via suppressing β-catenin signalling pathway in experimental liver fibrosis

The intestinal barrier dysfunction is crucial for the development of liver fibrosis but can be disturbed by intestinal chronic inflammation characterized with cyclooxygenase‐2 (COX‐2) expression. This study focused on the unknown mechanism by which COX‐2 regulates intestinal epithelial homeostasis in liver fibrosis. The animal models of liver fibrosis induced with TAA were established in rats and in intestinal epithelial–specific COX‐2 knockout mice. The impacts of COX‐2 on intestinal epithelial homeostasis via suppressing β‐catenin signalling pathway were verified pharmacologically and genetically in vivo. A similar assumption was tested in Ls174T cells with goblet cell phenotype in vitro. Firstly, disruption of intestinal epithelial homeostasis in cirrhotic rats was ameliorated by celecoxib, a selective COX‐2 inhibitor. Then, β‐catenin signalling pathway in cirrhotic rats was associated with the activation of COX‐2. Furthermore, intestinal epithelial–specific COX‐2 knockout could suppress β‐catenin signalling pathway and restore the disruption of ileal epithelial homeostasis in cirrhotic mice. Moreover, the effect of COX‐2/PGE2 was dependent on the β‐catenin signalling pathway in Ls174T cells. Therefore, inhibition of COX‐2 may enhance intestinal epithelial homeostasis via suppression of the β‐catenin signalling pathway in liver fibrosis.

Involvement of TLR4 signaling regulated-COX2/PGE2 axis in liver fibrosis induced by Schistosoma japonicum infection

Background

Hepatic stellate cell (HSC) activation plays a pivotal role in hepatic inflammation and liver fibrosis. TLR4 pathway activation has been reported to be involved in mice liver fibrosis induced by hepatitis virus infection, alcohol abuse, biliary ligation, carbon tetrachloride 4 treatment, and Schistosoma japonicum (Sj) infection. The effect and mechanisms of the cyclooxygenase 2 (COX2)/prostanoid E2 (PGE2) axis on liver fibrosis induced by Sj are still unclear.

Methods

Mice liver fibrosis were induced by cutaneous infection of Sj cercariae. COX-2 inhibitor, NS398 were injected from week 5 to week 7, while TLR4 inhibitor TAK242 were injected from week 4 to week 8 post Sj infection. Human HSCs line, LX-2 cells were cultured and exposed to LPS or synthetic PGE2, or pretreated by TAK242, TLR4-siRNA or NS398. Liver tissue and serum or in vitro cultured cell lysaste were collected at indicated time courses for exploring the relationship between TLR4 and COX2-PGE2 axis through qPCR, western blot, immunohistochemical assay, ect. One-way analysis of variance among multiple groups followed by Uncorrected Fisher’s LSD-t test or paired comparisons through t test were performed to tell the statistical differences.

Results

This study investigated the link between the COX2/PGE2 axis and TLR4 signaling in the induction of liver fibrogenesis in mice during Sj infection and in vitro culture of HSC strain-LX-2. The COX2/PGE2 axis was positively associated with Sj-induced liver fibrosis. TLR4 pathway activation stimulated the COX2/PGE2 axis in Sj-infected mice and in lipopolysaccharide (LPS)-exposed cultured HSCs. Synthetic PGE2 activated cultured HSCs through upregulation of alpha smooth muscle actin (α-SMA) expression. In LPS-triggered HSCs, NS398, a COX2 inhibitor, led to suppression of PGE2 synthesis and reduced expression of α-SMA and type I collagen (COL I).

Conclusions

These results indicate firstly the positive association of the COX2/PGE2 axis with liver fibrosis induced by Sj infection. TLR4 signaling may at least partially control the COX2/PGE2 axis in Sj-infected mice liver and in vitro cultured HSCs. The COX2/PGE2-EP2/EP4 axis might be a good drug target against liver fibrosis induced by Sj infection.

Graphic abstract

The Roles of Various Prostaglandins in Fibrosis: A Review

Organ fibrosis is a common pathological result of various chronic diseases with multiple causes. Fibrosis is characterized by the excessive deposition of extracellular matrix and eventually leads to the destruction of the tissue structure and impaired organ function. Prostaglandins are produced by arachidonic acid through cyclooxygenases and various prostaglandin-specific synthases. Prostaglandins bind to homologous receptors on adjacent tissue cells in an autocrine or paracrine manner and participate in the regulation of a series of physiological or pathological processes, including fibrosis. This review summarizes the properties, synthesis, and degradation of various prostaglandins, as well as the roles of these prostaglandins and their receptors in fibrosis in multiple models to reveal the clinical significance of prostaglandins and their receptors in the treatment of fibrosis.

Role of 2‑series prostaglandins in the pathogenesis of type 2 diabetes mellitus and non‑alcoholic fatty liver disease (Review)

Nowadays, metabolic syndromes are emerging as global epidemics, whose incidence are increasing annually. However, the efficacy of therapy does not increase proportionately with the increased morbidity. Type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD) are two common metabolic syndromes that are closely associated. The pathogenic mechanisms of T2DM and NAFLD have been studied, and it was revealed that insulin resistance, hyperglycemia, hepatic lipid accumulation and inflammation markedly contribute to the development of these two diseases. The 2-series prostaglandins (PGs), a subgroup of eicosanoids, including PGD₂, PGE₂, PGF_2α and PGI₂, are converted from arachidonic acid catalyzed by the rate-limiting enzymes cyclooxygenases (COXs). Considering their wide distribution in almost every tissue, 2-series PG pathways exert complex and interlinked effects in mediating pancreatic β-cell function and proliferation, insulin sensitivity, fat accumulation and lipolysis, as well as inflammatory processes. Previous studies have revealed that metabolic disturbances, such as hyperglycemia and hyperlipidemia, can be improved by treatment with COX inhibitors. At present, an accumulating number of studies have focused on the roles of 2-series PGs and their metabolites in the pathogenesis of metabolic syndromes, particularly T2DM and NAFLD. In the present review, the role of 2-series PGs in the highly intertwined pathogenic mechanisms of T2DM and NAFLD was discussed, and important therapeutic strategies based on targeting 2-series PG pathways in T2DM and NAFLD treatment were provided.

Role of G Protein-Coupled Receptors in Hepatic Stellate Cells and Approaches to Anti-Fibrotic Treatment of Non-Alcoholic Fatty Liver Disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) is globally increasing. Gaining control over disease-related events in non-alcoholic steatohepatitis (NASH), an advanced form of NAFLD, is currently an unmet medical need. Hepatic fibrosis is a critical prognostic factor in NAFLD/NASH. Therefore, a better understanding of the pathophysiology of hepatic fibrosis and the development of related therapies are of great importance. G protein-coupled receptors (GPCRs) are cell surface receptors that mediate the function of a great variety of extracellular ligands. GPCRs represent major drug targets, as indicated by the fact that about 40% of all drugs currently used in clinical practice mediate their therapeutic effects by acting on GPCRs. Like many other organs, various GPCRs play a role in regulating liver function. It is predicted that more than 50 GPCRs are expressed in the liver. However, our knowledge of how GPCRs regulate liver metabolism and fibrosis in the different cell types of the liver is very limited. In particular, a better understanding of the role of GPCRs in hepatic stellate cells (HSCs), the primary cells that regulate liver fibrosis, may lead to the development of drugs that can improve hepatic fibrosis in NAFLD/NASH. In this review, we describe the functions of multiple GPCRs expressed in HSCs, their roles in liver fibrogenesis, and finally speculate on the development of novel treatments for NAFLD/NASH.

A network pharmacology approach to investigating the mechanism of Tanshinone IIA for the treatment of liver fibrosis

ETHNOPHARMACOLOGICAL REVELVANCE

Tanshinone IIA (TIIA) is a major component extracted from the traditional herbal medicine salvia miltiorrhiza (Danshen), which activates blood circulation and treats chronic hepatitis and liver fibrosis. However, the underlying molecular mechanism of TIIA against hepatic fibrosis is still largely unknown.

AIM OF THE STUDY

The present study aimed to evaluate the antifibrotic effects of TIIA in liver fibrosis and investigate its underlying mechanism through network pharmacology-based prediction and experimental verification.

MATERIALS AND METHODS

In this study, a "TIIA-targets-liver fibrosis" network was constructed by combining the TIIA-specific and hepatic fibrosis-specific targets with protein-protein interactions (PPIS), and network pharmacology was applied to identify the potential targets and mechanisms of TIIA in the treatment of hepatic fibrosis. The antifibrotic effect of TIIA was investigated in CCl4-induced liver fibrosis in rats in vivo and in the human HSC line LX2 in vitro.

RESULTS

We identified 75 potential targets of TIIA and 1382 targets of liver fibrosis. Subsequently, the 29 target proteins that overlapped between the potential TIIA targets and the liver fibrosis targets indicated that TIIA has potential antifibrotic effects through regulating multiple targets, including c-Jun, c-Myc, CCND1, MMP9 and P65. Pathway and functional enrichment analysis of these putative targets showed that TIIA could regulate the MAPK, PI3K/Akt and Wnt signaling pathways. Consistently, in vivo and in vitro experiments indicated that TIIA attenuated CCl4-induced liver injury and fibrosis and inhibited hepatic stellate cell (HSC) proliferation and activation; these findings were concomitant with the decreased expression of α-smooth muscle actin (α-SMA) and human α2 (I) collagen (COL1A2). Moreover, TIIA remarkably downregulated the expression of c-Jun, c-Myc, MMP9, PI3K and P38 proteins, which were upregulated in CCl4-induced hepatic fibrosis in vivo. TIIA significantly downregulated the expression of c-Jun, p-c-Jun, c-Myc, CCND1, MMP9, P65, P-P65, PI3K and P38 proteins, which were upregulated during HSC activation in vitro.

CONCLUSION

Our study demonstrated that TIIA could significantly improve liver function, decrease liver injury, alleviate ECM accumulation, and attenuate HSC proliferation and activation, thus exerting an antifibrotic effect. The possible molecular mechanism involved MAPK, Wnt and PI3K/Akt signaling pathways via inhibiting c-Jun, p-c-Jun, c-Myc, CCND1, MMP9, P65, P-P65, PI3K and P38. Overall, our results suggest that TIIA could alleviate liver fibrosis through multiple targets and multiple signaling pathways and provide deep insight into the pharmacological mechanisms of TIIA in the treatment of hepatic fibrosis.

Caspase-11 promotes allergic airway inflammation

Activated caspase-1 and caspase-11 induce inflammatory cell death in a process termed pyroptosis. Here we show that Prostaglandin E₂ (PGE₂) inhibits caspase-11-dependent pyroptosis in murine and human macrophages. PGE₂ suppreses caspase-11 expression in murine and human macrophages and in the airways of mice with allergic inflammation. Remarkably, caspase-11-deficient mice are strongly resistant to developing experimental allergic airway inflammation, where PGE₂ is known to be protective. Expression of caspase-11 is elevated in the lung of wild type mice with allergic airway inflammation. Blocking PGE₂ production with indomethacin enhances, whereas the prostaglandin E₁ analog misoprostol inhibits lung caspase-11 expression. Finally, alveolar macrophages from asthma patients exhibit increased expression of caspase-4, a human homologue of caspase-11. Our findings identify PGE₂ as a negative regulator of caspase-11-driven pyroptosis and implicate caspase-4/11 as a critical contributor to allergic airway inflammation, with implications for pathophysiology of asthma.

Caspase 11 activation involves transcriptional upregulation and proteolytic cleavage. Here the authors show that prostaglandin E₂ prevents caspase-11-mediated pyroptosis, blocking caspase-11 mRNA and protein upregulation in macrophages and in vivo, and that mice lacking caspase-11 are strongly protected from allergic airway inflammation.

The Phenylethanol Glycoside Liposome Inhibits PDGF-Induced HSC Activation via Regulation of the FAK/PI3K/Akt Signaling Pathway

Cistanche tubulosa is a traditional Chinese herbal medicine that is widely used to regulate immunity, and phenylethanol glycosides (CPhGs) are among the primary components responsible for this activity. However, the application of CPhGs is negatively affected by their poor absorption and low oral utilization. Targeted drug delivery is an important development direction for pharmaceutics. Previous studies have indicated that CPhGs could block the conduction of the signaling pathways in TGF-β1/smad and inhibit the activation of hepatic stellate cells (HSCs). The aim of this study was to evaluate the anti-hepatic fibrosis effect of CPhG liposomes by inhibiting HSC activation, promoting apoptosis, blocking the cell cycle, suppressing the conduction of signaling pathways in focal adhesion kinase(FAK)/phosphatidylinositol-3-kinase(PI3K)/protein kinase B(Akt), and determining their in vitro hepatoprotective activity. In vitro release studies demonstrated that CPhG liposomes have a sustained release effect compared to drug CPhGs. HSC proliferation was inhibited after treatment with the CPhG liposomes (29.45, 14.72, 7.36 µg/mL), with IC50 values of 42.54 µg/mL in the MTT assay. Different concentrations of the CPhG liposomes could inhibit HSC proliferation, promote apoptosis, and block the cell cycle. The MTT method showed an obvious inhibition of HSC proliferation after CPhG liposome and Recombinant Rat Platelet-derived growth factor-BB(rrPDGF-BB) treatment. The levels of collagen-1, metallopeptidase inhibitor 1 (TIMP-1), α smooth muscle actin (α-SMA), and phosphorylated PI3K/Akt were downregulated, and matrix metalloproteinase-1 (MMP-1) was upregulated, by pretreatment with different concentrations of CPhG liposomes. Moreover, 29.45 μg/mL of CPhG liposomes could decrease the expression of the FAK protein and the phosphorylated PI3K and Akt protein downstream of FAK by overexpression of the FAK gene. This experiment suggests that CPhG liposomes may inhibit the activation of HSCs by inhibiting FAK and then reducing the expression of phosphorylated Akt/PI3K, thereby providing new insights into the application of CPhGs for liver fibrosis.

Exosomal MALAT1 derived from hepatic cells is involved in the activation of hepatic stellate cells via miRNA-26b in fibrosis induced by arsenite

In the liver microenvironment, interactions among diverse types of hepatic cells are involved in liver fibrosis. In fibrotic tissues, exosomes act as transporters in intercellular communication. Long non-coding RNAs (lncRNAs) are involved in the activation of hepatic stellate cells (HSCs), which are participants in liver fibrosis. However, the functions of exosomal lncRNAs in liver fibrosis induced by arsenite are undefined. The purposes of the present study were (a) to determine if lncRNAs secreted from human hepatic (L-02) cells exposed to arsenite are shuttled to hepatic stellate LX-2 cells and (b) to establish their effects on LX-2 cells. In mice, MALAT1 was overexpressed in the progression of liver fibrosis induced by arsenite as well as in L-02 cells exposed to arsenite. Co-cultures with arsenite-treated L-02 cells induced the activation of LX-2 cells and overexpression of MALAT1. Arsenite-treated L-02 cells transported MALAT1 into LX-2 cells. Downregulation of MALAT1, which reduced the MALAT1 levels in exosomes derived from arsenite-treated L-02 cells, inhibited the activation of LX-2 cells. Additionally, exosomal MALAT1 derived from arsenite-treated L-02 cells promoted the activation of LX-2 cells via microRNA-26b regulation of COL1A2. Furthermore, circulating exosomal MALAT1 was up-regulated in people exposed to arsenite. In sum, exosomes derived from arsenite-treated hepatic cells transferred MALAT1 to HSCs, which induced their activation. These findings support the concept that, during liver fibrosis induced by arsenite, exosomal lncRNAs are involved in cell-cell communication.

Gentianella turkestanerum Showed Protective Effects on Hepatic Injury by Modulating the Endoplasmic Reticulum Stress and NF-κB Signaling Pathway

OBJECTIVE

To investigate the protective effects of Gentianella turkestanerum extraction by butanol (designated as GBA) on hepatic cell line L02 injury induced by carbon tetrachloride (CCl4) and hydrogen peroxide (H2O2).

METHODS

L02 cells were incubated with 5 µg/mL, 10 µg/mL, 20 µg/mL, 40 µg/mL, 60 µg/mL, 80 µg/mL and 100 µg/mL GBA for 24 hours, and then MTT assay was used to screen the cytotoxicity for GBA. Cells were divided into blank control group, CCl4/H2O2 model group, treated by CCl4 (20 mmol/L) or H2O2 (100 µmol/L); silymarin+CCl4/H2O2 group, treated by CCl4 (20 mmol/L) or H2O2 (100 µmol/L) and 5 µg/mL silymarin; GBA+CCl4/H2O2 group, treated by CCl4 (20 mmol/L) or H2O2 (100 µmol/L) and GBA (5 µg/mL, 10 µg/mL and 20 µg/mL). MTT assay was performed to determine the cellular activity. Malondialdehyde (MDA) content was determined using a commercial kit. The alanine transaminase (ALT), aspartate transaminase (AST) in the supernatant was determined. PE-Annexin V/7-ADD method was utilized to determine the apoptosis of cells. RT-PCR was used to evaluate the expression of endoplasmic reticulum stressrelated genes (CHOP, PERK, IRE1 and ATF6) mRNA. Western blot analysis was performed to determine the expression of CHOP, Caspase 12 and NF-κB protein.

RESULTS

Cellular survival after GBA (5 µg/mL, 10 µg/mL and 20 µg/mL) incubation was ≥ 75%. After GBA incubation, levels of ALT and AST showed a significant decrease (P < 0.05), while that of the MDA showed a significant decrease (P < 0.05). The apoptosis in the CCl4 or H2O2 group showed a significant increase compared to the control group (P < 0.05). In contrast, GBA-preincubation could attenuate the cellular apoptosis compared to the CCl4 or H2O2 group, which displayed a dose-dependent manner (P < 0.05). The expression of CHOP, PERK, IRE1 and ATF6 mRNA was significantly up-regulated in the presence of CCl4 or H2O2 (P < 0.05). Whereas, GBA induced a significant decrease in these mRNA thereafter (P < 0.05), together with a decrease in CHOP and Caspase 12 proteins (P < 0.05). Besides, it could attenuate the expression of NF-κB p65 in nuclear protein.

CONCLUSION

G. turkestanerum could inhibit the lipid peroxidation and increase the antioxidant activity. Also, it could inhibit the cellular apoptosis through down-regulating the transcriptional level of ERS related genes and proteins. This process was associated with the nuclear translocation of NF-κB p65 protein.

Mechanisms for the Resolution of Organ Fibrosis

Fibrosis is a dynamic process with the potential for reversibility and restoration of near-normal tissue architecture and organ function. Herein, we review mechanisms for resolution of organ fibrosis, in particular that involving the lung, with an emphasis on the critical roles of myofibroblast apoptosis and clearance of deposited matrix.

let-7a suppresses liver fibrosis via TGFβ/SMAD signaling transduction pathway

Liver fibrosis is the most common pathological outcome and the most severe complication of chronic liver diseases. Accumulating evidence suggests that miRNAs are involved in cell proliferation, differentiation, apoptosis, as well as the occurrence and development of various diseases. In this study, we found that the expression of let-7a was markedly decreased in the liver tissue samples and blood samples from patients with liver fibrosis compared with healthy volunteers. Furthermore, let-7a was downregulated in the liver tissues and blood samples in mouse models of liver fibrosis. Further analysis indicated that let-7a suppresses the activation level of hepatic stellate cells (HSCs). In addition, overexpression of let-7a reduced cell viability and promoted apoptosis of HSCs. Western blot analysis showed that let-7a might inhibit HSCs through TGFβ/SMAD signaling pathway. The present study provides a potential accurate target and vital evidence to better understand the underlying pathogenesis for early diagnosis and treatment of liver fibrosis.

Identification of mRNA-miRNA crosstalk in human endothelial cells after exposure of PM2.5 through integrative transcriptome analysis

PM2.5 has implications in cardiovascular adverse events, but the underlying mechanisms are still obscure. The aim of this study is to evaluate miRNA expression in endothelial cells in response to two realistic doses of PM2.5 and to identify the possible gene targets of deregulated miRNAs through microarray profiling and computational technology. As a result, there are 18 differentially expressed miRNAs between 2.5 μg/cm² group and the control, of which 11 miRNAs are up-regulated and 7 miRNAs are down-regulated. Relative to the control group, 40 miRNAs are significantly changed in 10 μg/cm² group with 21 miRNAs being upregulated and 19 miRNAs being downregulated. Interestingly, when two PM2.5-treated groups respectively compared with the control, the expressed trends of 12 miRNAs in 2.5 μg/cm² group are the same as those in 10 μg/cm² group, with 8 being upregulated and 4 miRNAs being simultaneously downregulated. Gene ontology (GO) analysis shows that the crucial functional categories of miRNA-targeted genes incorporate transcription-related process and intracellular signal transduction. Pathway analysis reveals that endocytosis, FoxO signaling pathway and PI3K-Akt signaling pathway are involved in the PM2.5-caused cardiotoxicity. Further confirmation by RT-qPCR indicates that PM2.5 could induce the down-regulation of hsa-miR-128-3p, hsa-miR-96-5p, hsa-miR-28-5p, hsa-miR-4478 and hsa-miR-6808-5p, which are in accordance with the results of array data. With the comprehensive analysis of mRNAs and miRNAs, a great number of pairs have been identified, suggesting abnormally expressed miRNAs have functions in the cardiotoxicity of PM2.5, and the function may be achieved through the post-transcriptional regulation of certain genes on the related pathways.

Curcumin-loaded PLA-PEG copolymer nanoparticles for treatment of liver inflammation in streptozotocin-induced diabetic rats

This report focused on loading curcumin (CUR) drug into biodegradable Polylactide-poly(ethylene glycol) (PLA-PEG) copolymer nanoparticles as an effective anti-inflammatory agent in vivo to overcome the limitations resulted from the free CUR. By a simple nano-emulsification technique, hydrophobic CUR was loaded into hydrophobic polymer's segments and stabilized by cationic surfactant. They were then characterized by DLS, TEM, and SEM techniques providing monodispersed and spherical nanoparticles with an average diameter of 117 nm and high surface charge of +35 mV. Thereafter, they were orally administrated into five groups of rats, typically, control (healthy rats), streptozotocin (STZ)-induced diabetic rats, diabetics treated with free CUR, diabetics treated with PLA-PEG NPs, and diabetics treated with CUR-encapsulated PLA-PEG NPs. Next, complete blood analyses were assessed including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and nuclear factor kappa B (NF-ҡB), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), cyclooxygenase (COX-2), Peroxisome proliferator-activated receptors (PPAR-γ) and transforming growth factor-β1 (TGF-β1). The obtained results demonstrated that diabetes initially produced liver inflammation in rats manifested by leveraging the mean levels of serum AST, ALT inducing oxidative stress resulting in a clear increase in the levels of hepatic MDA and NO concomitant with a remarkable decrease in GSH. Moreover, diabetes significantly increased serum NF-ҡB, hepatic COX-2 and TGF-β1, while highly reduced hepatic PPAR-γ. In contrast, both CUR free and CUR-encapsulated NPs ameliorated the negative changes in diabetes but CUR-encapsulated NPs showed more pronounced treated effect than free CUR. In addition, histopathological investigations were performed on the liver tissues of all groups, showing a mitigation in inflammation while treating with CUR-NPs.

MicroRNA-351-5p aggravates intestinal ischaemia/reperfusion injury through the targeting of MAPK13 and Sirtuin-6

BACKGROUND AND PURPOSE

Intestinal ischaemia-reperfusion (II/R) injury is a serious clinical problem. Here we have investigated novel mechanisms and new drug targets in II/R injury by searching for microRNAs regulating such injury.

EXPERIMENTAL APPROACH

We used hypoxia/reoxygenation (H/R) of IEC-6 cell cultures and models of II/R models in rats and mice. Microarray assays were used to identify target miRNAs from rat intestinal. Real-time PCR, Western blot and dual luciferase reporter assays, and agomir and antagomir in vitro and in vivo were used to assess the effects of the target miRNA on II/R injury.

KEY RESULTS

The miR-351-5p was differentially expressed in our models and it targeted MAPK13 and sirtuin-6. This miRNA reduced levels of sirtuin-6 and AMP-activated protein kinase phosphorylation, and activated forkhead box O3 (FoxO3α) phosphorylation to cause oxidative stress. Also, miR-351-5p markedly reduced MAPK13 level, activated polycystic kidney disease 1/NF-κB signal and increased NF-κB (p65). Moreover, miR-351-5p up-regulated levels of Bcl2-associated X, cytochrome c, apoptotic peptidase activating factor 1, cleaved-caspase 3 and cleaved-caspase 9 by reducing sirtuin-6 levels to promote apoptosis. In addition, miR-351-5p mimic in IEC-6 cells and agomir in mice aggravated these effects, and miR-351-5p inhibitor and antagomir in mice alleviated these actions.

CONCLUSIONS AND IMPLICATIONS

Our data showed that miR-351-5p aggravated II/R injury by promoting intestinal mucosal oxidative stress, inflammation and apoptosis by targeting MAPK13 and sirtuin-6.These data provide new insights into the mechanisms regulating II/R injury, and of miR-351-5p could be considered as a novel therapeutic target for such injury.