An HNF1α-regulated feedback circuit modulates hepatic fibrogenesis via the crosstalk between hepatocytes and hepatic stellate cells

New Evidence for the Mechanisms of Nanoplastics Amplifying Cadmium Cytotoxicity: Trojan Horse Effect, Inflammatory Response, and Calcium Imbalance

Nanoplastics (NPs) are emerging pollutants worldwide. Particularly worrisome is that although studies have reported that NPs can amplify the biotoxicity of environmental pollutants, the specific mechanism remains unclear. Here, we found that NPs, even without significant toxicity (cell survival: 99.11%), amplified the hepatocyte toxicity of Cd2+. Mechanistically, higher Cd2+ uptake (Δ = 23.80%) combined with crucial intracellular desorption behavior of Cd2+ loaded in NPs (desorption rate: 82.70%) were identified as prerequisites for NPs amplifying Cd2+ cytotoxicity. As for toxigenic pathways, the inflammatory response and calcium (Ca) signaling pathway were identified as the primary molecular events leading to the amplification of Cd2+ cytotoxicity. Further phenotypic monitoring revealed that NPs synergized with Cd2+ to induce more severe pyroptosis and apoptosis by activating the inflammatory caspase-1-dependent and Ca2+-mitochondrial-caspase-3 pathways to a greater extent, respectively. This study reveals and proves for the first time the "Trojan horse" effects of NPs, thus elucidating the actual mechanisms by which NPs act as toxicity amplifiers of pollutants, providing significant insights into accurate risk assessment of NPs in composite pollution.

The METTL3/m6A Reader Protein YTHDF1 Regulates Endothelial Cell Pyroptosis by Enhancing NLRP3 Expression to Affect Soft Tissue Injury

Background

Pyroptosis is inflammation-associated programmed cell death triggered by activation of the NOD-like receptor protein 3 (NLRP3) inflammasome, which plays a crucial role in acute soft tissue injury (ASTI). This study aimed to explore whether methyltransferase-like 3 (METTL3) can regulate NLRP3 expression through N6-methyladenosine (m6A) modification to mediate endothelial cell pyroptosis and thus affect soft tissue injury.

Methods

An experimental ASTI rat model was created by inducing muscle injury through striking the rat muscle. In vitro, an ASTI cell model was established using human umbilical vein endothelial cells (HUVECs) stimulated with lipopolysaccharide (LPS) and ATP. The severity of ASTI in rats was evaluated using H&E staining. To assess protein levels, Western blot and Immunohistochemistry (IHC) analyses were performed, focusing on METTL3, pyroptosis-associated proteins, and m6A reader proteins. Immunofluorescence (IF) assay was conducted to examine the expression of NLRP3 and CD31. The levels of inflammatory cytokines were measured using an ELISA assay, while flow cytometry was used to detect levels of ROS and cellular pyroptosis. The m6A levels in cells were analyzed by RNA m6A colorimetry. The interactions between METTL3 and NLRP3, and YTHDF1 and NLRP3 were analyzed using RIP and RNA pull-down assays, respectively.

Results

METTL3 and YTHDF1 were significantly upregulated in ASTI rats and LPS-ATP-induced HUVECs. Knockdown of METTL3 ameliorated ASTI and inhibited cellular pyroptosis. Knockdown of METTL3 reduced the levels of total m6A and NLRP3 m6A in HUVECs and suppressed NLRP3 expression. Meanwhile, knockdown of YTHDF1 decreased NLRP3 protein expression without affecting NLRP3 mRNA levels. In addition, overexpression of NLRP3 was able to reverse the effect of METTL3 on LPS-ATP-induced endothelial cell pyroptosis.

Conclusion

The METTL3/m6A reader protein YTHDF1 regulates endothelial cell pyroptosis by enhancing NLRP3 expression to affect soft tissue injury.

The hepatocyte nuclear factor 1 homeobox A (HNF1A) gene polymorphism and AFP serum levels in Egyptian HCC patients

Background

Hepatocyte nuclear factors were first identified as liver-enriched transcription factors that might participate in various activities related to the transcription of genes unique to the liver.

Objective

The study aimed to reveal the impact of HNF1A gene variations on disease progression in hepatocellular carcinoma (HCC) patients and its relation to serum alpha-fetoprotein level.

Methods

Participants in the study were classified as Group I, 32 HCC patients; Group II, 36 chronic hepatitis C patients; and Group III, 26 healthy volunteers as a control group.

Each patient underwent full history taking, thorough clinical examination, and radiological examination. Furthermore, tumor staging was done using BCLC staging system. HNF1A gene polymorphisms (rs 2,464,196 and rs 1,169,310) were genotyped by real-time PCR.

Results

The findings revealed the highest frequency of AA and GA genotypes of HNF1A (rs2464196) polymorphism in both HCC (P = 0.002) and chronic HCV (P = 0.004) patients in comparison with controls. Regarding rs1169310gene polymorphism, no significant variation was observed across various genotypes when comparing the experimental groups to the control group. Additionally, HCC patients harboring the AA genotype for rs2464196 had significantly increased AFP (≥ 200 ng/ml) levels, whereas HCC patients with rs1169310 SNPs for HNF1A had no significant association regarding the AFP level.

Conclusion

The rs2464196 polymorphism of HNF1 is associated with increased AFP levels and HCC disease progression, which may be a prognostic and diagnostic genetic indicator.

NLRP3 inflammasome inhibition decreases Schistosomiasis japonica-induced granulomatous inflammation and fibrosis in BALB/c mice

To research the role of the NLRP3 inflammasome in Schistosoma japonicum-induced granuloma formation and liver fibrosis. In in vivo tests, BALB/c mice were used. shNLRP3 plasmid based on adeno-associated virus serotype 8 (AAV8-shNLRP3) was injected to block NLRP3 inflammasome via tail vein. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were detected to assess liver injury. H&E staining was used for routine histopathological assessment; Masson's trichrome staining was used to detect fibrous tissues and collagen fibers. Hepatic expression of NLRP3, procaspase-1, bioactive caspase-1, collagen-1, tissue inhibitor of metalloproteinases-1 (TIMP-1), and α-smooth muscle actin (α-SMA) were detected by western blot. Serum levels of IL-1β were detected by enzyme-linked immunosorbent assay (ELISA). The inflammatory cell infiltration and hepatic expression of IL-1β around the granuloma were detected by immunohistochemistry staining. Treatment of S. japonicum infected mice with AAV8-shNLRP3 significantly reduced the hepatic levels of bioactive caspase-1 and IL-1β, as well as circulating IL-1β concentrations, while reducing the amounts of myeloperoxidase (MPO) and F4/80 positive cells around the granuloma. Moreover, collagen deposition, TIMP-1, and α-SMA, which are markers of hepatic stellate cell (HSC) activation, were reduced around the liver granuloma. These findings highlight a therapeutic potential of AAV8-shNLRP3 in schistosomiasis cirrhosis.

Ba-Qi-Rougan formula alleviates hepatic fibrosis by suppressing hepatic stellate cell activation via the MSMP/CCR2/PI3K pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The Ba-Qi-Rougan formula (BQRGF) is a traditional and effective compound prescription from Traditional Chinese Medicine (TCM) utilized in treating hepatic fibrosis (HF).

AIM OF THE STUDY

We aimed to evaluate the therapeutic efficacy of BQRGF on HF and explore the underlying mechanisms of action.

MATERIALS AND METHODS

UPLC-Q-TOF-MS technology was employed to identify the material basis of BQRGF. Mice with carbon tetrachloride (CCl4)-induced HF received BQRGF at three doses (3.87, 7.74, and 15.48 g/kg per day). We examined serum and liver biochemical indicators and liver histology to assess the therapeutic impact. Primary mouse cells were isolated and utilized for experimental analysis. MSMP expression levels were examined in vitro and in vivo experimental models, including human and mouse tissue. Furthermore, lentivirus and small interfering RNA (siRNA) transfections were employed to manipulate microseminoprotein (MSMP) expression in LO2 cells (human normal liver cells). These manipulated LO2 cells were then co-cultured with LX2 human hepatic stellate cells (HSCs). Through the modulation of MSMP expression in co-cultured cells, administering recombinant MSMP (rMSMP) with or without BQRGF-medicated serum, and using specific pathway inhibitors or agonists in LX2 cells, we elucidated the underlying mechanisms.

RESULTS

A total of 48 compounds were identified from BQRGF, with 12 compounds being absorbed into the bloodstream and 9 compounds being absorbed into the liver. Four weeks of BQRGF treatment in the HF mouse model led to significant improvements in biochemical and molecular assays and histopathology, particularly in the medium and high-dose groups. These improvements included a reduction in the level of liver injury and fibrosis-related factors. MSMP levels were elevated in human and mouse fibrotic liver tissues, and this increase was mitigated in HF mice treated with BQRGF. Moreover, primary cells and co-culture studies revealed that BQRGF reduced MSMP expression, decreased the expression of the hepatic stellate cell (HSC) activation markers, and suppressed critical phosphorylated protein levels in the CCR2/PI3K/AKT pathway. These findings were further validated using CCR2/PI3K/AKT signaling inhibitors and agonists in MSMP-activated LX2 cells.

CONCLUSIONS

Collectively, our results suggest that BQRGF combats HF by diminishing MSMP levels and inhibiting MSMP-induced HSC activation through the CCR2/PI3K/AKT pathway.

A comprehensive review of miR-21 in liver disease: Big impact of little things

microRNAs (miRNAs), a class of non-coding RNA with 20-24 nucleotides, are defined as the powerful regulators for gene expression. miR-21 is a multifunctional miRNA enriched in the circulatory system and multiple organs, which not only serves as a non-invasive biomarker in disease diagnosis, but also participates in many cellular activities. In various chronic liver diseases, the increase of miR-21 affects glycolipid metabolism, viral infection, inflammatory and immune cell activation, hepatic stellate cells activation and tissue fibrosis, and autophagy. Moreover, miR-21 is also a liaison in the deterioration of chronic liver disease to hepatocellular carcinoma (HCC), and it impacts on cell proliferation, apoptosis, migration, invasion, angiogenesis, immune escape, and epithelial-mesenchymal transformation by regulating target genes expression in different signaling pathways. In current research on miRNA therapy, some natural products can exert the hepatoprotective effects depending on the inhibition of miR-21 expression. In addition, miR-21-based therapeutic also play a role in regulating intracellular miR-21 levels and enhancing the efficacy of chemotherapy drugs. Herein, we systemically summarized the recent progress of miR-21 on biosynthesis, biomarker function, molecular mechanism and miRNA therapy in chronic liver disease and HCC, and looked forward to outputting some information to enable it from bench to bedside.

Tripartite motif 8 promotes the progression of hepatocellular carcinoma via mediating ubiquitination of HNF1α

Tripartite motif 8 (TRIM8) is an E3 ligase that plays dual roles in various tumor types. The biological effects and underlying mechanism of TRIM8 in hepatocellular carcinoma (HCC) remain unknown. Hepatocyte nuclear factor 1α (HNF1α) is a key transcriptional factor that plays a significant role in regulating hepatocyte differentiation and liver function. The reduced expression of HNF1α is a critical event in the development of HCC, but the underlying mechanism for its degradation remains elusive. In this study, we discovered that the expression of TRIM8 was upregulated in HCC tissues, and was positively correlated with aggressive tumor behavior of HCC and shorter survival of HCC patients. Overexpression of TRIM8 promoted the proliferation, colony formation, invasion, and migration of HCC cells, while TRIM8 knockdown or knockout exerted the opposite effects. RNA sequencing revealed that TRIM8 knockout suppresses several cancer-related pathways, including Wnt/β-catenin and TGF-β signaling in HepG2 cells. TRIM8 directly interacts with HNF1α, promoting its degradation by catalyzing polyubiquitination on lysine 197 in HCC cells. Moreover, the cancer-promoting effects of TRIM8 in HCC were abolished by the HNF1α-K197R mutant in vitro and in vivo. These data demonstrated that TRIM8 plays an oncogenic role in HCC progression through mediating the ubiquitination of HNF1α and promoting its protein degradation, and suggests targeting TRIM8-HNF1α may provide a promising therapeutic strategy of HCC.

Association Between Gadoxetic Acid-Enhanced Magnetic Resonance Imaging, Organic Anion Transporters, and Farnesoid X Receptor in Benign Focal Liver Lesions

The organic anion uptake and efflux transporters [organic anion-transporting polypeptide (OATP)1B1, OATP1B3 and multidrug resistance-associated protein (MRP)2 and MRP3] that mediate the transport of the hepatobiliary-specific contrast agent gadoxetate (Gd-EOB-DTPA) are direct or indirect targets of the farnesoid X receptor (FXR), a key regulator of bile acid and lipid homeostasis. In benign liver tumors, FXR expression and activation is not yet characterized. We investigated the expression and activation of FXR and its targets in hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH) and their correlation with Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI). Gd-EOB-DTPA MRI patterns were assessed by an expert radiologist. The intensity of the lesions on the hepatobiliary phase was correlated to mRNA expression levels of OATP1B1, OATP1B3, MRP2, MRP3, FXR, and small heterodimer partner (SHP) in fresh surgical specimens of patients with FNH or HCA subtypes. Normal and tumor sample pairs of 43 HCA and 14 FNH were included. All FNH (14/14) were hyperintense. Of the 34 HCA with available Gd-EOB-DTPA-enhanced MRI, 6 were hyperintense and 28 HCA were hypointense. OATP1B3 was downregulated in the hypointense tumors compared with normal surrounding liver tissue (2.77±3.59 vs. 12.9±15.6, P < 0.001). A significant positive correlation between FXR expression and activation and OATP1B3 expression level was found in the HCA cohort. SHP showed a trend toward downregulation in hypointense HCA. In conclusion, this study suggests that the MRI relative signal in HCA may reflect expression level and/or activity of SHP and FXR. Moreover, our data confirms the pivotal role of OATP1B3 in Gd-EOB-DTPA uptake in HCA. SIGNIFICANCE STATEMENT: FXR represents a valuable target for the treatment of liver disease and metabolic syndrome. Currently, two molecules, ursodeoxycholate and obeticholate, are approved for the treatment of primary biliary cirrhosis and cholestasis, with several compounds in clinical trials for the treatment of metabolic dysfunction-associated fatty liver disease. Because FXR expression and activation is associated with gadoxetate accumulation in HCA, an atypical gadoxetate-enhanced MRI pattern might arise in patients under FXR-targeted therapy, thereby complicating the differential diagnosis.

Pro-Inflammatory and Anti-Inflammatory Interleukins in Infectious Diseases: A Comprehensive Review

Interleukins (ILs) are signaling molecules that are crucial in regulating immune responses during infectious diseases. Pro-inflammatory ILs contribute to the activation and recruitment of immune cells, whereas anti-inflammatory ILs help to suppress excessive inflammation and promote tissue repair. Here, we provide a comprehensive overview of the role of pro-inflammatory and anti-inflammatory ILs in infectious diseases, with a focus on the mechanisms underlying their effects, their diagnostic and therapeutic potential, and emerging trends in IL-based therapies.

Hepatocyte FoxO1 Deficiency Protects From Liver Fibrosis via Reducing Inflammation and TGF-β1-mediated HSC Activation

BACKGROUND & AIMS

The O-class of the forkhead transcription factor FoxO1 is a crucial factor mediating insulin→PI3K→Akt signaling and governs diverse cellular processes. However, the role of hepatocyte FoxO1 in liver fibrosis has not been well-established. In his study, we investigated the role of hepatocyte FoxO1 in liver fibrosis and uncovered the underlying mechanisms.

METHODS

Liver fibrosis was established by carbon tetrachloride (CCL4) administration and compared between liver-specific deletion of FoxO1 deletion (F1KO) and control (CNTR) mice. Using genetic and bioinformatic strategies in vitro and in vivo, the role of hepatic FoxO1 in liver fibrosis and associated mechanisms was established.

RESULTS

Increased FoxO1 expression and FoxO1 signaling activation were observed in CCL4-induced fibrosis. Hepatic FoxO1 deletion largely attenuated CCL4-induced liver injury and fibrosis compared with CNTR mice. F1KO mice showed ameliorated CCL4-induced hepatic inflammation and decreased TGF-β1 mRNA and protein levels compared with those of CNTR mice. In primary hepatocytes, FoxO1 deficiency reduced TGF-β1 expression and secretion. Conditioned medium (CM) collected from wild-type hepatocytes treated with CCL4 activated human HSC cell line (LX-2); such effect was attenuated by FoxO1 deletion in primary hepatocytes or neutralization of TGF-β1 in the CM using TGF-β1 antibody. Hepatic FoxO1 overexpression in CNTR mice promoted CCL4-induced HSC activation; such effect was blocked in L-TGF-β1KO mice.

CONCLUSIONS

Hepatic FoxO1 mediates CCL4-inducled liver fibrosis via upregulating hepatocyte TGF-β1 expression, stimulating hepatic inflammation and TGF-β1-mediated HSC activation. Hepatic FoxO1 may be a therapeutic target for prevention and treatment of liver fibrosis.

Three-dimensional molecular architecture of mouse organogenesis

Mammalian embryos exhibit sophisticated cellular patterning that is intricately orchestrated at both molecular and cellular level. It has recently become apparent that cells within the animal body display significant heterogeneity, both in terms of their cellular properties and spatial distributions. However, current spatial transcriptomic profiling either lacks three-dimensional representation or is limited in its ability to capture the complexity of embryonic tissues and organs. Here, we present a spatial transcriptomic atlas of all major organs at embryonic day 13.5 in the mouse embryo, and provide a three-dimensional rendering of molecular regulation for embryonic patterning with stacked sections. By integrating the spatial atlas with corresponding single-cell transcriptomic data, we offer a detailed molecular annotation of the dynamic nature of organ development, spatial cellular interactions, embryonic axes, and divergence of cell fates that underlie mammalian development, which would pave the way for precise organ engineering and stem cell-based regenerative medicine.

Enhanced apoptotic index in hepatocytes, Kupffer cells, and inflammatory infiltrate showed positive correlation with hepatic lesion intensity, parasite load, and clinical status in naturally Leishmania-infected dogs

It is unknown if Leishmania amastigote infections affect hepatocytes and Kupffer cell apoptosis, and the role played by apoptosis in liver lesions in leishmaniasis is still unclear. Clinically affected and subclinically infected dogs with leishmaniosis and uninfected controls were assessed. Parasite load, biochemical markers for evaluation of liver damage, morphometry (area, perimeter, number of inflammatory focus, major and minor diameters), apoptosis in hepatic tissue (hepatocytes, Kupffer cells, and inflammatory infiltrates) and cellularity in inflammatory foci were quantified. The parasite load in clinically affected dogs proved to be higher than in the other groups. All morphometric parameters (area, perimeter, number of inflammatory focus, major and minor diameters) from clinically affected were higher than the values found in the subclinically infected and uninfected control dogs. Only clinically affected dogs presented high levels of ALT, FA, GGT and cholesterol in serum. Strong positive correlation was observed between biochemical markers for evaluation of liver damage (ALT, FA, GGT and cholesterol) and hepatic apoptosis (hepatocytes, Kupffer cells, and inflammation). Clinically affected dogs showed a more intense hepatic lesion. Hepatocytes showed a higher rate of apoptosis in Leishmania-infected dogs than in uninfected control dogs. The Kupffer cell apoptotic index and apoptosis within the inflammatory infiltrates were higher in clinically affected dogs. The apoptotic index evaluated in hepatocytes, Kupffer cells, and inflammatory infiltrates showed a positive correlation with the intensity of the hepatic lesion, parasite load, and clinical status. Apoptotic cells also showed positive immunostaining for TUNEL, Bcl2, and Bax. Our data showed that hepatic apoptosis was related to the severity of liver damage, the progression of infection, and the parasite load in leishmaniasis. Apoptotic regulated cell recruitment modulated the inflammatory response and favored the survival and dissemination of parasites, depending on the clinical status of the Leishmania-infected dogs.

Hepatocyte-derived MASP1-enriched small extracellular vesicles activate HSCs to promote liver fibrosis

BACKGROUND AND AIMS

Liver fibrosis is a chronic disease characterized by different etiological agents; dysregulated interactions between hepatocytes and HSCs contribute to this disease. β-arrestin 1 (ARRB1) plays an important role in liver fibrosis; however, the effect of ARRB1 on the crosstalk between hepatocytes and HSCs in liver fibrosis is unknown. The aim of this study is to investigate how ARRB1 modulates hepatocyte and HSC activation during liver fibrosis.

APPROACH AND RESULTS

Normal and fibrotic human liver and serum samples were obtained. CCl 4 -induced liver fibrosis and methionine-choline deficiency-induced NASH models were constructed. Primary hepatocytes and HSCs were isolated, and human hepatic LO2 and stellate LX2 cells were used. Small extracellular vesicles (EVs) were purified, and key proteins were identified. ARRB1 was up-regulated in hepatocytes and associated with autophagic blockage in liver fibrosis. ARRB1 increased the release of hepatocyte-derived small EVs by inhibiting multivesicular body lysosomal degradation and activating Rab27A, thereby activating HSCs. Proteomic analyses showed that mannan-binding lectin serine protease 1 (MASP1) was enriched in hepatocyte-derived small EVs and activated HSCs via p38 mitogen-activated protein kinase (MAPK)/activating transcription factor 2 (ATF2) signaling. ARRB1 up-regulated MASP1 expression in hepatocytes. MASP1 promoted liver fibrosis in mice. Clinically, MASP1 expression was increased in the serum and liver tissue of patients with liver fibrosis.

CONCLUSIONS

ARRB1 up-regulates the release of hepatocyte-derived MASP1-enriched small EVs by regulating the autophagic-lysosomal/multivesicular body pathway and Rab27A. Hepatocyte-derived MASP1 activates HSCs to promote liver fibrogenesis through p38 MAPK/ATF2 signaling. Thus, MASP1 is a pivotal therapeutic target in liver fibrosis.

Roles of protein tyrosine phosphatases in hepatocellular carcinoma progression (Review)

Hepatocellular carcinoma (HCC) represents almost 80% of all liver cancers, is the sixth most common cancer and is the second‑highest cause of cancer‑related deaths worldwide. Protein tyrosine phosphatases (PTPs), which are encoded by the largest family of phosphatase genes, play critical roles in cellular responses and are implicated in various signaling pathways. Moreover, PTPs are dysregulated and involved in various cellular processes in numerous cancers, including HCC. Kinases and phosphatases are coordinators that modulate cell activities and regulate signaling responses. There are multiple interacting signaling networks, and coordination of these signaling networks in response to a stimulus determines the physiological outcome. Numerous issues, such as drug resistance and inflammatory reactions in the tumor microenvironment, are implicated in cancer progression, and the role of PTPs in these processes has not been well elucidated. Therefore, the present review focused on discussing the relationship of PTPs with inflammatory cytokines and chemotherapy/targeted drug resistance, providing detailed information on how PTPs can modulate inflammatory reactions and drug resistance to influence progression in HCC.

Depletion of Tgfbr2 in hepatocytes alleviates liver fibrosis and restores hepatic function in fibrotic mice

OBJECTIVES

Previous studies have demonstrated the pivotal role of transforming growth factor (TGF)-β signaling in activating hepatic stellate cells during liver fibrosis. In this study we aimed to demonstrate the effects and underlying mechanism of TGF-β signaling in hepatocytes on hepatic fibrogenesis.

METHODS

Hepatocyte-specific Tgfbr2-knockout (Tgfbr2^HKO ) mice were generated by AAV8-TBG-Cre injection via the tail vein of Tgfbr2^f/f mice. CCl₄ was injected intraperitoneally twice a week for 4 weeks to establish the fibrotic mouse model. The expression of the fibrogenesis markers was evaluated by immunohistochemistry, western blot, and real-time polymerase chain reaction (PCR). RNA-seq analysis was used to detect the transcriptional profiles of primary hepatocytes isolated from Tgfbr2^HKO mice and control mice.

RESULTS

The expression of TβR2 (Tgfbr2) was markedly upregulated in hepatocytes of the fibrotic liver. Tgfbr2 depletion in hepatocytes decreased the expressions of profibrogenic markers (Col1a1 and Acta2) in the CCl₄ -treated fibrotic liver. RNA-seq analysis revealed that Tgfbr2 deletion in hepatocytes significantly reduced the inflammatory response and suppressed epithelial-mesenchymal transition of hepatocytes accompanied by upregulation of the metabolic pathways during liver fibrosis. Moreover, the expressions of hepatocyte nuclear factors (HNFs), including Hnf4α, Foxa1, Foxa2, and Foxa3, which are important for maintaining liver metabolism and homeostasis, were decreased in fibrotic livers and significantly increased after Tgfbr2 blockade.

CONCLUSION

Blocking the TGF-β signaling pathway in hepatocytes reduces hepatic fibrosis and improves hepatic function in fibrotic livers.

Repair of Limb Ischemia Is Dependent on Hematopoietic Stem Cell Specific-SHP-1 Regulation of TGF-β1

BACKGROUND

Hematopoietic stem cell (HSC) therapy has shown promise for tissue regeneration after ischemia. Therefore, there is a need to understand mechanisms underlying endogenous HSCs activation in response to ischemic stress and coordination of angiogenesis and repair. SHP-1 plays important roles in HSC quiescence and differentiation by regulation of TGF-β1 signaling. TGF-β1 promotes angiogenesis by stimulating stem cells to secrete growth factors to initiate the formation of blood vessels and later aid in their maturation. We propose that SHP-1 responds to ischemia stress in HSC and progenitor cells (HSPC) via regulation of TGF-β1.

METHODS

A mouse hind limb ischemia model was used. Local blood perfusion in the limbs was determined using laser doppler perfusion imaging. The number of positive blood vessels per square millimeter, as well as blood vessel diameter (μm) and area (μm²), were calculated. Hematopoietic cells were analyzed using flow cytometry. The bone marrow transplantation assay was performed to measure HSC reconstitution.

RESULTS

After femoral artery ligation, TGF-β1 was initially decreased in the bone marrow by day 3 of ischemia, followed by an increase on day 7. This pattern was opposite to that in the peripheral blood, which is concordant with the response of HSC to ischemic stress. In contrast, SHP-1 deficiency in HSC is associated with irreversible activation of HSPCs in the bone marrow and increased circulating HSPCs in peripheral blood following limb ischemia. In addition, there was augmented auto-induction of TGF-β1 and sustained inactivation of SHP-1-Smad2 signaling, which impacted TGF-β1 expression in HSPCs in circulation. Importantly, restoration of normal T GF-β1 oscillations helped in the recovery of limb repair and function.

CONCLUSIONS

HSPC-SHP-1-mediated regulation of TGF-β1 in both bone marrow and peripheral blood is required for a normal response to ischemic stress.

A transcriptional regulatory network of HNF4α and HNF1α involved in human diseases and drug metabolism

HNF4α and HNF1α are core transcription factors involved in the development and progression of a variety of human diseases and drug metabolism. They play critical roles in maintaining the normal growth and function of multiple organs, mainly the liver, and in the metabolism of endogenous and exogenous substances. The twelve isoforms of HNF4α may exhibit different physiological functions, and HNF4α and HNF1α show varying or even opposing effects in different types of diseases, particularly cancer. Additionally, the regulation of CYP450, phase II drug-metabolizing enzymes, and drug transporters is affected by several factors. This article aims to review the role of HNF4α and HNF1α in human diseases and drug metabolism, including their structures and physiological functions, affected diseases, regulated drug metabolism genes, influencing factors, and related mechanisms. We also propose a transcriptional regulatory network of HNF4α and HNF1α that regulates the expression of target genes related to disease and drug metabolism.

Hepatocyte Nuclear Factor 1α Proinflammatory Effect Linked to the Overexpression of Liver Nuclear Factor–κB in Experimental Model of Chronic Kidney Disease

Chronic kidney disease (CKD) is associated with low-grade inflammation that activates nuclear factor–κB (NF–κB), which upregulates the expression of numerous NF–κB responsive genes, including the genes encoding IL-6, ICAM-1, VCAM-1, and MCP-1. Herein, we found the coordinated overexpression of genes encoding RelA/p65 (a subunit of NF–κB) and HNF1α in the livers of chronic renal failure (CRF) rats—an experimental model of CKD. The coordinated overexpression of RelA/p65 and HNF1α was associated with a significant increase in IL-6, ICAM-1, VCAM-1, and MCP-1 gene expressions. A positive correlation between liver RelA/p65 mRNA levels and a serum concentration of creatinine and BUN suggest that RelA/p65 gene transcription is tightly related to the progression of renal failure. The knockdown of HNF1α in the HepG2 cell line by siRNA led to a decrease in Rel A/p65 mRNA levels. This was associated with a decrease in IL-6, ICAM-1, VCAM-1, and MCP-1 gene expressions. The simultaneous repression of HNF-1α and RelA/p65 by clofibrate is tightly associated with the downregulation of IL-6, ICAM-1, VCAM-1, and MCP-1 gene expression. In conclusion, our findings suggest that NF–κB could be a downstream component of the HNF1α-initiated signaling pathway in the livers of CRF rats.

Feedback loop between hepatocyte nuclear factor 1α and endoplasmic reticulum stress mitigates liver injury by downregulating hepatocyte apoptosis

Hepatocyte nuclear factor alpha (HNF1α), endoplasmic reticulum (ER) stress, and hepatocyte apoptosis contribute to severe acute exacerbation (SAE) of liver injury. Here, we explore HNF1α-ER stress-hepatocyte apoptosis interaction in liver injury. LO2, HepG2 and SK-Hep1 cells were treated with thapsigargin (TG) or tunicamycin (TM) to induce ER stress. Carbon tetrachloride (CCl4) was used to induce acute liver injury in mice. Low-dose lipopolysaccharide (LPS) exacerbated liver injury in CCl4-induced mice. Significant apoptosis, HNF1α upregulation, and nuclear factor kappa B (NF-κB) activation were observed in human-derived hepatocytes during ER stress. Knockdown of Rela, NF-κB p65, inhibited the HNF1α upregulation. Following CCl4 treatment ER stress, apoptosis, HNF1α expression and RelA phosphorylation were significantly increased in mice. HNF1α knockdown reduced activating transcription factor 4 (ATF4) expression, and aggravated ER stress as well as hepatocyte apoptosis in vivo and in vitro. The double fluorescent reporter gene assay confirmed that HNF1α regulated the transcription of ATF4 promoter. LPS aggravated CCl4-induced liver injury and reduced HNF1α, and ATF4 expression. Therefore, in combination, HNF1α and ER stress could be mutually regulated forming a feedback loop, which helps in protecting the injured liver by down-regulating hepatocyte apoptosis. Low-dose LPS aggravates hepatocyte apoptosis and promotes the SAE of liver injury by interfering with the feedback regulation of HNF1α and ER stress in acute liver injury.

Rifaximin Ameliorates Non-alcoholic Steatohepatitis in Mice Through Regulating gut Microbiome-Related Bile Acids

Non-alcoholic steatohepatitis (NASH) is the progressive stage of non-alcoholic fatty liver disease (NAFLD). The non-absorbable antibiotic rifaximin has been used for treatment of irritable bowel syndrome, traveling diarrhea, and hepatic encephalopathy, but the efficacy of rifaximin in NASH patients remains controversial. This study investigated the effects and underlying mechanisms of rifaximin treatment in mice with methionine and choline deficient (MCD) diet-induced NASH. We found that rifaximin greatly ameliorated hepatic steatosis, lobular inflammation, and fibrogenesis in MCD-fed mice. Bacterial 16S rRNA sequencing revealed that the gut microbiome was significantly altered in MCD-fed mice. Rifaximin treatment enriched 13 amplicon sequence variants (ASVs) belonging to the groups Muribaculaceae, Parabacteroides, Coriobacteriaceae_UCG-002, uncultured Oscillospiraceae, Dubosiella, Rikenellaceae_RC9_gut_group, Mucispirillum, and uncultured Desulfovibrionaceae. However, rifaximin treatment also reduced seven ASVs in the groups Aerococcus, Oscillospiraceae, uncultured Ruminococcaceae, Bilophila, Muribaculaceae, Helicobacter, and Alistipes in MCD-fed mice. Bile acid-targeted metabolomic analysis indicated that the MCD diet resulted in accumulation of primary bile acids and deoxycholic acid (DCA) in the ileum. Rifaximin delivery reduced DCA levels in MCD-fed mice. Correlation analysis further showed that DCA levels were associated with differentially abundant ASVs modulated by rifaximin. In conclusion, rifaximin may ameliorate NASH by decreasing ileal DCA through alteration of the gut microbiome in MCD-fed mice. Rifaximin treatment may therefore be a promising approach for NASH therapy in humans.

Disruption of Tumor Suppressors HNF4α/HNF1α Causes Tumorigenesis in Liver

The hepatocyte nuclear factor-4α (HNF4α) and hepatocyte nuclear factor-1α (HNF1α) are transcription factors that influence the development and maintenance of homeostasis in a variety of tissues, including the liver. As such, disruptions in their transcriptional networks can herald a number of pathologies, such as tumorigenesis. Largely considered tumor suppressants in liver cancer, these transcription factors regulate key events of inflammation, epithelial-mesenchymal transition, metabolic reprogramming, and the differentiation status of the cell. High-throughput analysis of cancer cell genomes has identified a number of hotspot mutations in HNF1α and HNF4α in liver cancer. Such results also showcase HNF1α and HNF4α as important therapeutic targets helping us step into the era of personalized medicine. In this review, we update current findings on the roles of HNF1α and HNF4α in liver cancer development and progression. It covers the molecular mechanisms of HNF1α and HNF4α dysregulation and also highlights the potential of HNF4α as a therapeutic target in liver cancer.

Stem Cell-based Therapy Strategy for Hepatic Fibrosis by Targeting Intrahepatic Cells

The whole liver transplantation is the most effective treatment for end-stage fibrosis. However, the lack of available donors, immune rejection and total cost of surgery remain as the key challenges in advancing liver fibrosis therapeutics. Due to the multi-differentiation and low immunogenicity of stem cells, treatment of liver fibrosis with stem cells has been considered as a valuable new therapeutic modality. The pathological progression of liver fibrosis is closely related to the changes in the activities of intrahepatic cells. Damaged hepatocytes, activated Kupffer cells and other inflammatory cells lead to hepatic stellate cells (HSCs) activation, further promoting apoptosis of damaged hepatocytes, while stem cells can work on fibrosis-related intrahepatic cells through relevant transduction pathways. Herein, this article elucidates the phenomena and the mechanisms of the crosstalk between various types of stem cells and intrahepatic cells including HSCs and hepatocytes in the treatment of liver fibrosis. Then, the important influences of chemical compositions, mechanical properties and blood flow on liver fibrosis models with stem cell treatment are emphasized. Clinical trials on stem cell-based therapy for liver fibrosis are also briefly summarized. Finally, continuing challenges and future directions of stem cell-based therapy for hepatic fibrosis are discussed. In short, stem cells play an important advantage and have a great potential in treating liver fibrosis by interacting with intrahepatic cells. Clarifying how stem cells interact with intrahepatic cells to change the progression of liver fibrosis is of great significance for a deeper understanding of liver fibrosis mechanisms and targeted therapy.

Fas/FasL mediates NF-κBp65/PUMA-modulated hepatocytes apoptosis via autophagy to drive liver fibrosis

Fas/Fas ligand (FasL)-mediated cell apoptosis involves a variety of physiological and pathological processes including chronic hepatic diseases, and hepatocytes apoptosis contributes to the development of liver fibrosis following various causes. However, the mechanism of the Fas/FasL signaling and hepatocytes apoptosis in liver fibrogenesis remains unclear. The Fas/FasL signaling and hepatocytes apoptosis in liver samples from both human sections and mouse models were investigated. NF-κBp65 wild-type mice (p65^f/f), hepatocytes specific NF-κBp65 deletion mice (p65Δhepa), p53-upregulated modulator of apoptosis (PUMA) wild-type (PUMA-WT) and PUMA knockout (PUMA-KO) littermate models, and primary hepatic stellate cells (HSCs) were also used. The mechanism underlying Fas/FasL-regulated hepatocytes apoptosis to drive HSCs activation in fibrosis was further analyzed. We found Fas/FasL promoted PUMA-mediated hepatocytes apoptosis via regulating autophagy signaling and NF-κBp65 phosphorylation, while inhibition of autophagy or PUMA deficiency attenuated Fas/FasL-modulated hepatocytes apoptosis and liver fibrosis. Furthermore, NF-κBp65 in hepatocytes repressed PUMA-mediated hepatocytes apoptosis via regulating the Bcl-2 family, while NF-κBp65 deficiency in hepatocytes promoted PUMA-mediated hepatocytes apoptosis and enhanced apoptosis-linked inflammatory response, which contributed to the activation of HSCs and liver fibrogenesis. These results suggest that Fas/FasL contributes to NF-κBp65/PUMA-modulated hepatocytes apoptosis via autophagy to enhance liver fibrogenesis, and this network could be a potential therapeutic target for liver fibrosis.

PTPN6 promotes chemosensitivity of colorectal cancer cells via inhibiting the SP1/MAPK signalling pathway

The abnormal expression of protein tyrosine phosphatase nonreceptor type 6 (PTPN6) has been proved to be associated with the progression of colorectal cancer. However, its role in chemosensitivity and related molecular mechanism have not been clarified. It has been reported that PTPN6 was down-regulated in colorectal cancer cells compared with the normal colorectal cells. To evaluate the effects of PTPN6 on the proliferation and survival of colorectal cancer cells, PTPN6 was overexpressed in colorectal cancer cells in the present study. We found that cell proliferation and viability were both decreased after overexpression of PTPN6. The IC50 of 5-Fu against colorectal cells was also declined in PTPN6 transfected cells. And further, we verified that PTPN6 could down-regulate the expression of P-gp and MRP-1. Moreover, SP1 was the target protein of PTPN6 predicated by ChIPBase software and confirmed through Co-immunoprecipitation assay and it was negatively regulated by PTPN6. To further verify the effect of SP1 on chemoresistance, SP1 was overexpressed. SP1 overexpression enhanced the drug-resistance to 5-Fu and abrogated the effects of PTPN6 upregulation on 5-Fu resistance. All the above changes were associated with the down-regulation of proteins related to MAPK signalling pathway, such as phosphorylation of extracellular regulated protein kinases (ERK) and p38. In summary, PTPN6 promoted chemosensitivity of colorectal cancer cells by targeting SP1 and inhibiting the activation of MAPK signalling pathway. SIGNIFICANCE OF THE STUDY: It has been demonstrated that the abnormal expression of PTPN6 was related to the progression of colorectal cancer. However, the chemosensitivity of PTPN6 and its molecular mechanisms were still unclear. Here, we identified that PTPN6 was down-regulated in colorectal cancer cells. Moreover, PTPN6 overexpression not only reduced cell proliferation and viability, but decreased the resistance of colorectal cells to 5-Fu. In our research, we found that the SP1 was the target protein of PTPN6 and it was negatively regulated by PTPN6. In addition, SP1 could increase the resistance of colorectal cells to 5-Fu. Molecular mechanism studies have shown that PTPN6 promoted the chemosensitivity of colorectal cancer cells by inhibiting the activation of MAPK signalling pathway.

MicroRNA-92b-3p promotes the progression of liver fibrosis by targeting CREB3L2 through the JAK/STAT signaling pathway

Liver fibrosis is a common feature of almost all chronic liver diseases, which eventually leads to cirrhosis and even hepatocellular carcinoma (HCC). The current study showed that miR-92b plays an important role in the progression of HCC but its role in liver fibrosis is still unclear. Here we aimed to explore the role and underlying molecular mechanism of miR-92b-3p in the activated hepatic stellate cells (HSCs) and the pathological process of hepatic fibrosis. We found that miR-92b-3p was highly expressed both in fibrotic liver tissues from patients and model mice and in activated LX-2 cells stimulated with TGF-β1. However, the expression of miR-92b-3p was downregulated in inactivated LX-2 cells treated with adipogenic differentiation mixture (MDI). In addition, we found that miR-92b-3p mimic could promote the activation, proliferation, and migration of LX-2 and HSC-T6 cells, while miR-92b-3p inhibitor could reverse this process. From the TargetScan databases, we found that CREB3L2 is a potential target of miR-92b-3p and the luciferase assay revealed the suppressed CREB3L2 expression by miR-92b-3p. Mechanistically, we found that miR-92b-3p promotes the activation of HSCs and thereby the progression of liver fibrosis by activating JAK/STAT pathway via targeting CREB3L2, providing a new target for the diagnosis and treatment of liver fibrosis.

Overexpression of Rhophilin Rho GTPase-binding protein 2 promotes hepatocellular carcinoma

Hepatocellular carcinoma is a serious public health problem in China. The mortality rate associated with the majority of cancer types has decreased as a result of targeted therapy. However, the mortality rates associated with hepatocellular carcinoma have not improved; therefore, the identification of new molecular targets is required for the development of novel targeted therapies. In the present study, a new molecular target, Rhophilin Rho GTPase-binding protein 2 (RHPN2), was identified. The levels of RHPN2 protein in tumor tissues were assessed via immunohistochemistry, while the mRNA levels were analyzed via reverse transcription-quantitative PCR. Additionally, cell viability was tested via MTT analysis. RHPN2 expression was upregulated in hepatocellular carcinoma tissues compared with that of matched adjacent normal tissues. More importantly, low expression of RHPN2 in patients with hepatocellular carcinoma was associated with an improved prognosis rate compared with patients with high expression. Downregulation of RHPN2 reduced the proliferation of hepatocellular carcinoma cells and increased the rate of apoptosis, whereas overexpression of RHPN2 demonstrated the opposite effects. Hepatocyte nuclear factor 1α was implicated in the mechanism of RHPN2. Overall, these data indicated that overexpression of RHPN2 may promote hepatocellular carcinoma.

HMGB1 Inhibits HNF1A to Modulate Liver Fibrogenesis via p65/miR-146b Signaling

High mobility group box 1 (HMGB1) is essential for the pathogenesis of liver injury and liver fibrosis. We previously revealed that miR-146b promotes hepatic stellate cells (HSCs) activation and proliferation. Nevertheless, the potential mechanisms are still unknown. Herein, HMGB1 increased HSCs proliferation and COL1A1 and α-SMA protein levels. However, the knockdown of miR-146b inhibited HSCs proliferation and COL1A1 and α-SMA protein levels induced via HMGB1 treatment. miR-146b was upregulated by HMGB1 and miR-146b targeted hepatocyte nuclear factor 1A (HNF1A) 3'-untranslated region (3'UTR) to modulate its expression negatively. Further, we confirmed that HMGB1 might elicit miR-146b expression via p65 within HSCs. Knockdown or block of HMGB1 relieved the CCl₄-induced liver fibrosis. In fibrotic liver tissues, miR-146b expression was positively correlated with p65 mRNA, but HNF1A mRNA was inversely correlated with p65, and miR-146b expression. In summary, our findings suggest that HMGB1/p65/miR-146b/HNF1A signaling exerts a crucial effect on liver fibrogenesis via the regulation of HSC function.

SHP-1 ameliorates nonalcoholic steatohepatitis by inhibiting proinflammatory cytokine production

Inflammation is the main contributor for the pathogenesis of nonalcoholic steatohepatitis (NASH). Src homology region 2 domain-containing phosphatase 1 (SHP-1, also known as PTPN6) is regarded as a negative regulator of inflammation, but its role in NASH remains unknown. Here, hepatocyte-specific Ptpn6 knockout mice (Ptpn6^HKO ) and adenovirus vector-mediated ectopic expression of SHP-1 (AdSHP1) were used to evaluate the role of SHP-1 in a methionine- and choline-deficient diet-induced NASH model. Compared with the control littermates, Ptpn6^HKO mice show exacerbated hepatic steatosis, inflammation, and fibrosis. Additionally, administration of AdSHP1 significantly ameliorates steatohepatitis and inhibits the expression of proinflammatory cytokines, including transforming growth factor-β, interleukin-6, and tumor necrosis factor-α. Our data indicate that SHP-1 could be a potential therapeutic target for NASH.

Hepatic stellate cell activation promotes alcohol-induced steatohepatitis through Igfbp3 and SerpinA12

BACKGROUND & AIMS

Steatohepatitis drives fibrogenesis in alcohol-related liver disease. Recent studies have suggested that hepatic stellate cells (HSCs) may regulate the parenchymal cell injury and inflammation that precedes liver fibrosis, although the mechanism remains incompletely defined. Neuropilin-1 (NRP-1) and synectin are membrane proteins implicated in HSC activation. In this study, we disrupted NRP-1 and synectin as models to evaluate the role of HSC activation on the development of steatohepatitis in response to alcohol feeding in mice.

METHODS

Mice with HSC-selective deletion of NRP (ColCre/Nrp1loxP) or synectin (ColCre/synectinloxP) vs. paired Nrp1loxP or synectinloxP mice were fed a control diet or the chronic/binge alcohol feeding model. Several markers of steatosis and inflammation were evaluated.

RESULTS

ColCre/Nrp1loxP mice showed less fibrosis, as expected, but also less inflammation and steatosis, with lower hepatic triglyceride content. Similar results were observed in the synectin model. Hepatocytes treated with supernatant of HSCs from ColCre/Nrp1loxP mice compared to supernatant from Nrp1loxP mice were protected against ethanol-induced lipid droplet formation. An adipokine and inflammatory protein array from the supernatant of HSCs with NRP-1 knockdown showed a significant reduction in Igfbp3 (a major insulin-like growth factor-binding protein with multiple metabolic functions) and an increase in SerpinA12 (a serine-protease inhibitor) secretion compared to wild-type HSCs. Recombinant Igfbp3 induced lipid droplets, triglyceride accumulation, and lipogenic genes in hepatocytes in vitro, while SerpinA12 was protective against ethanol-induced steatosis. Finally, Igfbp3 was increased, and SerpinA12 was decreased in serum and liver tissue from patients with alcoholic hepatitis.

CONCLUSION

Selective deletion of NRP-1 from HSCs attenuates alcohol-induced steatohepatitis through regulation of Igfbp3 and SerpinA12 signaling.

LAY SUMMARY

Hepatic stellate cells are known for their role in fibrosis (scarring of the liver). In this study, we describe their role in the modulation of fat deposition and inflammation in the liver, which occurs secondary to alcohol damage.

The Roles of Long Noncoding RNAs HNF1α-AS1 and HNF4α-AS1 in Drug Metabolism and Human Diseases

Long noncoding RNAs (lncRNAs) are RNAs with a length of over 200 nucleotides that do not have protein-coding abilities. Recent studies suggest that lncRNAs are highly involved in physiological functions and diseases. lncRNAs HNF1α-AS1 and HNF4α-AS1 are transcripts of lncRNA genes HNF1α-AS1 and HNF4α-AS1, which are antisense lncRNA genes located in the neighborhood regions of the transcription factor (TF) genes HNF1α and HNF4α, respectively. HNF1α-AS1 and HNF4α-AS1 have been reported to be involved in several important functions in human physiological activities and diseases. In the liver, HNF1α-AS1 and HNF4α-AS1 regulate the expression and function of several drug-metabolizing cytochrome P450 (P450) enzymes, which also further impact P450-mediated drug metabolism and drug toxicity. In addition, HNF1α-AS1 and HNF4α-AS1 also play important roles in the tumorigenesis, progression, invasion, and treatment outcome of several cancers. Through interacting with different molecules, including miRNAs and proteins, HNF1α-AS1 and HNF4α-AS1 can regulate their target genes in several different mechanisms including miRNA sponge, decoy, or scaffold. The purpose of the current review is to summarize the identified functions and mechanisms of HNF1α-AS1 and HNF4α-AS1 and to discuss the future directions of research of these two lncRNAs.

Tormentic acid inhibits hepatic stellate cells activation via blocking PI3K/Akt/mTOR and NF-κB signalling pathways

The present study was to investigate the inhibitory effect and underlying mechanism of Tormentic acid (TA) on hepatic stellate cells (HSCs). HSC-T6 cells were stimulated with Platelet-derived growth factor-BB (PDGF-BB) and TA, and then cell proliferation, apoptosis, inflammatory factor, and collagen-related indicators were detected. In order to elucidate the potential mechanism, the PI3K/Akt/mTOR and NF-κB signalling pathways were also detected. The results showed that TA treatment markedly inhibited PDGF-BB-stimulated HSC-T6 cell activation, as evidenced by the inhibition of cell proliferation, migration and colony formation, as well as the decreased expression of TGF-β and α-SMA. TA treatment caused a significant increase in the activity of lactate dehydrogenase and significantly promoted cell apoptosis. TA treatment significantly reduced aspartate aminotransferase, alanine aminotransferase and total bilirubin activity. Importantly, TA inhibited the expression of collagen type I and III, alleviating the excessive deposition of extracellular matrix (ECM). Further experiments showed that TA administration significantly inhibited the phosphorylation of PI3K, Akt, FAK and mTOR and the protein expression of P70S6K, indicating the inhibition of the PI3K/Akt/mTOR pathway. Moreover, treatment with TA markedly decreased the phosphorylation of IκBα, NF-κB p65 and IKKα/β, thereby blocking the NF-κB signal transduction. In summary, this study demonstrates that TA significantly inhibits HSC activation and promotes cell apoptosis via the inhibition of the PI3K/Akt/mTOR and NF-κB signalling pathways. SIGNIFICANCE OF THE STUDY: Tormentic acid (TA) could inhibit HSC activation and alleviate collagen-based ECM deposition, suggesting that TA exerted anti-hepatic fibrosis. Further mechanism research revealed that the inhibition of TA on HSC activation might be through blocking the PI3K/Akt/mTOR and NF-κB signalling pathways. These findings provided a new cue to understand the protective effect of TA against liver fibrosis, which may provide a potential nature medicine for the treatment of liver fibrosis.

Construction of gold-siRNA NPR1 nanoparticles for effective and quick silencing of NPR1 in Arabidopsis thaliana

In recent years, gold nanoparticles (AuNPs) have been widely used as gene silencing agents and therapeutics for treatment of cancers due to their high transfection efficiency and lack of cytotoxicity, but their roles in gene silencing in plants have not yet been reported. Here, we report synthesis of AuNPs-branched polyethylenimine and its integration with the small interfering RNAs (siRNA) of NPR1 to form a AuNPs-siRNA_NPR1 compound. Our results showed that AuNPs-siRNA_NPR1 was capable of infiltrating into Arabidopsis cells. AuNPs-siRNA_NPR1 silenced 80% of the NPR1 gene in Arabidopsis. Bacteriostatic and ion leakage experiments suggest that the NPR1 gene in Arabidopsis leaves was silenced by AuNPs-siRNA_NPR1. In Columbia-0 plants, compared with the control group treated with buffer solution, the AuNPs-siRNA_NPR1 treatment significantly increased the number of colonies and cell death, and the leaves turned yellow, similar to the phenotype of the npr1 leaves. These results indicated this AuNPs-siRNA_NPR1 silencing the NPR1 gene method is simple, effective and quick (3 days), and a powerful tool to study gene functions in plants.

Gold nanoparticles (AuNPs) have been widely used as gene silencing agents and therapeutics for treatment due to their high transfection efficiency and lack of cytotoxicity, but their roles in gene silencing in plants have not yet been reported.

RelB promotes liver fibrosis via inducing the release of injury-associated inflammatory cytokines

Liver fibrosis is a serious chronic disease that developed by a coordinated interplay of many cell types, but the underlying signal transduction in individual cell type remains to be characterized. Nuclear factor‐κB (NF‐κB) is a widely accepted central player in the development of hepatic fibrosis. However, the precise role of each member of NF‐κB in different cell type is unclear. Here, we generated a mouse model (Relb^Δhep) with hepatocyte‐specific deletion of RelB, a member of NF‐κB family. Relb^Δhep mice born normally and appear normal without obvious abnormality. However, in the CCl4‐induced liver fibrosis, Relb^Δhep mice developed less severe disease compared with wide‐type (WT) mice. The denaturation and necrosis of hepatocytes as well as the formation of false lobules in Relb^Δhep mice were significantly reduced compared with WT mice. The production of α‐SMA and the level of collagen I and Collagen III were greatly reduced in Relb^Δhep mice comparing with WT mice. Furthermore, in patients with liver fibrosis, RelB is up‐regulated along with the stage of diseases. Consistently, CCl4 treatment could up‐regulate the expression of RelB as well as inflammatory cytokines such as IL‐6 and TGF‐β1 in hepatoma cell as well as in WT mice. Knockdown the expression of RelB in hepatoma cells greatly reduced the expression of CCl4‐induced inflammatory cytokines. In summary, we provide the genetic evidence to demonstrate the critical and hepatocellular role of RelB in liver fibrosis. RelB is an important transcription factor to drive the expression of inflammatory cytokines in the initiation phase of injury.

Intercellular crosstalk of hepatic stellate cells in liver fibrosis: New insights into therapy

Liver fibrosis is a dynamic wound-healing process characterized by the net accumulation of extracellular matrix. There is no efficient antifibrotic therapy other than liver transplantation to date. Activated hepatic stellate cells (HSCs) are the major cellular source of matrix-producing myofibroblasts, playing a central role in the initiation and progression of liver fibrosis. Paracrine signals from resident and inflammatory cells such as hepatocytes, liver sinusoidal endothelial cells, hepatic macrophages, natural killer/natural killer T cells, biliary epithelial cells, hepatic progenitor cells, and platelets can directly or indirectly regulate HSC differentiation and activation. Intercellular crosstalk between HSCs and those "responded" cells has been a critical event involved in HSC activation and fibrogenesis. This review summarizes recent advancement regarding intercellular communication between HSCs and other "responded cells" during liver fibrosis and experimental models of intercellular crosstalk systems, and provides novel ideas for potential antifibrotic therapeutic strategy.

Phillygenin inhibits LPS-induced activation and inflammation of LX2 cells by TLR4/MyD88/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese medicine Forsythiae Fructus is the dried fruit of Forsythia suspensa (Thunb.) Vahl. It is commonly used to clear heat and detoxify, reduce swelling and disperse knot, and evacuate wind and heat.

AIM OF THE STUDY

Inflammation is involved in liver fibrosis. Phillygenin (PHI) is a kind of lignans extracted and separated from Forsythiae Fructus, which has been reported to have a good anti-inflammatory effect. Therefore, we aimed to explore whether PHI has a therapeutic effect on liver fibrosis caused by inflammation.

MATERIALS AND METHODS

Firstly, the induction of the LX2 cells inflammatory model and fibrosis model by LPS with different concentrations were studied. Then, high, medium and low doses PHI was given for intervention therapy. The secretion of IL-6, IL-1β and TNF-α inflammatory factors were detected by ELISA kit, and the expression of collagen I and α-SMA was detected by Western blot and RT-qPCR. The possible mechanism of PHI on TLR4/MyD88/NF-κB signal pathway was studied by computer-aided drug design software and the results were further verified by Western blot and RT-qPCR experiments.

RESULTS

The results showed that LPS could promote the expression of IL-6, IL-1β and TNF-α and the expression of collagen I and α-SMA, indicating that LPS could induce inflammation and fibrosis in LX2 cells. PHI could inhibit LX2 cell activation and fibrotic cytokine expression by inhibiting LPS-induced pro-inflammatory reaction. Molecular docking results showed that PHI could successfully dock with TLR4, MyD88, IKKβ, p65, IκBα, and TAK1 proteins. Subsequently, Western blot and qPCR results further proved that PHI could inhibit the proteins expression in TLR4/MyD88/NF-κB signal pathway which were consistent with the molecular docking results.

CONCLUSION

PHI can inhibit LPS-induced pro-inflammatory reaction and LX2 cell activation through TLR4/MyD88/NF-κB signaling pathway, thereby inhibiting liver fibrosis.

NPAS2 Contributes to Liver Fibrosis by Direct Transcriptional Activation of Hes1 in Hepatic Stellate Cells

Recently, emerging evidence shows that dysregulation of circadian genes is closely associated with liver fibrosis. However, how dysregulation of circadian genes promotes liver fibrosis is unknown. In this study, we show that neuronal PAS domain protein 2 (NPAS2), one of the core circadian molecules that has been shown to promote hepatocarcinoma cell proliferation, significantly contributed to liver fibrogenesis. NPAS2 is upregulated in hepatic stellate cells (HSCs) after fibrogenic injury, which subsequently contributes to the activation of HSCs. Mechanistically, NPAS2 plays a profibrotic role via direct transcriptional activation of hairy and enhancer of split 1 (Hes1), a critical transcriptor of Notch signaling for the fibrogenesis process, in HSCs. Our findings demonstrate that NPAS2 plays a critical role in liver fibrosis through direct transcriptional activation of Hes1, indicating that NPAS2 may serve as an important therapeutic target to reverse the progression of liver fibrosis.

Hepatic Nuclear Factor 1 Alpha (HNF-1α) In Human Physiology and Molecular Medicine

The transcription factors (TFs) play a crucial role in the modulation of specific gene transcription networks. One of the hepatocyte nuclear factors (HNFs) family's member, hepatocyte nuclear factor-1α (HNF-1α) has continuously become a principal TF to control the expression of genes. It is involved in the regulation of a variety of functions in various human organs including liver, pancreas, intestine, and kidney. It regulates the expression of enzymes involved in endocrine and xenobiotic activity through various metabolite transporters located in the above organs. Its expression is also required for organ-specific cell fate determination. Despite two decades of its first identification in hepatocytes, a review of its significance was not comprehended. Here, the role of HNF-1α in the above organs at the molecular level to intimate molecular mechanisms for regulating certain gene expression whose malfunctions are attributed to the disease conditions has been specifically encouraged. Moreover, the epigenetic effects of HNF-1α have been discussed here, which could help in advanced technologies for molecular pharmacological intervention and potential clinical implications for targeted therapies. HNF-1α plays an indispensable role in several physiological mechanisms in the liver, pancreas, intestine, and kidney. Loss of its operations leads to the non-functional or abnormal functional state of each organ. Specific molecular agents or epigenetic modifying drugs that reactivate HNF-1α are the current requirements for the medications of the diseases.

Multiple roles of microRNA-146a in immune responses and hepatocellular carcinoma

MicroRNAs (miRNAs/miRs), consisting of ~22 nucleotides of single-stranded RNA, participate in post-transcriptional gene regulation by binding to the 3′-untranslated region (UTR) of mRNAs, repressing their translation and promoting their degradation. Studies have shown that certain miRNAs play a key role in the control of various cellular activities, such as inhibiting inflammation, modulating cell differentiation and suppressing cancer growth. The role of miR-146a in the immune response and in the pathogenesis of hepatocellular carcinoma (HCC) has also been investigated. Although some studies have shown that increased miR-146a levels are associated with HCC, others have revealed that miR-146a suppresses cancer cell proliferation, invasion and metastasis. Toll-like receptor 4 (TLR4) signaling has an important role in regulating innate and adaptive immune responses. In addition, TLR4 is functionally expressed in HCC cells and promotes HCC cell proliferation, which can be regulated by miR-146a. The present review focuses on the recent progress in analyzing the multiple roles of miR-146a in mediating the TLR4 pathway and adaptive immune response. Finally, the function of miR-146a in the pathogenesis of HCC is also discussed.

TGFβ Impairs HNF1α Functional Activity in Epithelial-to-Mesenchymal Transition Interfering With the Recruitment of CBP/p300 Acetyltransferases

The cytokine transforming growth factor β (TGFβ) plays a crucial role in the induction of both epithelial-to-mesenchymal transition (EMT) program and fibro-cirrhotic process in the liver, where it contributes also to organ inflammation following several chronic injuries. All these pathological situations greatly increase the risk of hepatocellular carcinoma (HCC) and contribute to tumor progression. In particular, late-stage HCCs are characterized by constitutive activation of TGFβ pathway and by an EMT molecular signature leading to the acquisition of invasive and metastatic properties. In these pathological conditions, the cytokine has been shown to induce the transcriptional downregulation of HNF1α, a master regulator of the epithelial/hepatocyte differentiation and of the EMT reverse process, the mesenchymal-to-epithelial transition (MET). Therefore, the restoration of HNF1α expression/activity has been proposed as targeted therapeutic strategy for liver fibro-cirrhosis and late-stage HCCs. In this study, TGFβ is found to trigger an early functional inactivation of HNF1α during EMT process that anticipates the effects of the transcriptional downregulation of its own gene. Mechanistically, the cytokine, while not affecting the HNF1α DNA-binding capacity, impaired its ability to recruit CBP/p300 acetyltransferases on target gene promoters and, consequently, its transactivating function. The loss of HNF1α capacity to bind to CBP/p300 and HNF1α functional inactivation have been found to correlate with a change of its posttranslational modification profile. Collectively, the results obtained in this work unveil a new level of HNF1α functional inactivation by TGFβ and contribute to shed light on the early events triggering EMT in hepatocytes. Moreover, these data suggest that the use of HNF1α as anti-EMT tool in a TGFβ-containing microenvironment may require the design of new therapeutic strategies overcoming the TGFβ-induced HNF1α inactivation.

Puerarin alleviates liver fibrosis via inhibition of the ERK1/2 signaling pathway in thioacetamide-induced hepatic fibrosis in rats

Liver fibrosis is a complex pathological process and an early step in the progression of liver cirrhosis, which can eventually develop into hepatocellular carcinoma. Currently, there is no effective treatment for liver fibrosis. Puerarin is a traditional Chinese herb, which is commonly used in the treatment of various diseases. In addition, it is also believed to have a therapeutic effect in liver fibrosis. However, whether puerarin reduces liver fibrosis via the ERK1/2 signaling pathway to inhibit the activation of hepatic stellate cell (HSC) and excessive collagen deposition in liver fibrosis remains unknown. The aim of the current study was to establish a liver fibrosis in vivo model by intraperitoneal injection of thioacetamide (TAA) and investigate the effect of puerarin in the treatment of liver fibrosis. Hematoxylin and eosin and Van Gieson's staining were used to examine histopathological changes associated with liver fibrosis. Liver hydroxyproline content was examined to determine the total amount of collagen in the liver. The relative protein expression levels of transforming growth factor β1 (TGFβ1), α-smooth muscle actin (α-SMA), collagen type I, fibronectin, ERK1/2 and p-ERK1/2 were determined by western blot analysis. In the TAA group, histopathological changes and collagen fiber content in rat liver tissue samples were significantly increased compared with the control group (P<0.05). In addition, treatment with puerarin significantly decreased histopathological changes and collagen fiber content in rat liver tissue samples (P<0.05). The relative protein expression levels of TGFβ1, α-SMA, collagen type I, fibronectin and p-ERK1/2 were significantly upregulated in the TAA group compared with the control group (P<0.05), whereas puerarin treatment reversed these changes. These findings suggest that treatment with puerarin may reduce HSC activation and alleviate extracellular matrix protein expression levels by inhibiting the TGF-β/ERK1/2 pathway in liver fibrosis.

MicroRNA-134 deactivates hepatic stellate cells by targeting TGF-β activated kinase 1-binding protein 1

Aberrant expression of microRNAs is associated with liver fibrogenesis. We previously found that microRNA-134 (miR-134) expression was reduced in fibrosis-based hepatocarcinogenesis induced by diethylinitrosamine. Herein we investigate the role and mechanisms of miR-134 in hepatic fibrosis. Our data show that miR-134 expression is reduced in rat hepatic fibrogenesis induced by carbontetrachloride, bile duct ligation, and dimethylnitrosamine, as well as in activated hepatic stellate cells (HSCs). Moreover, miR-134 inhibited HSC proliferation, and decreased the expression of smooth muscle actin and collagen I in HSCs, whereas the miR-134 inhibitor increased HSC activation. MiR-134 also negatively regulated transforming growth factor-β-activated kinase 1-binding protein 1 (TAB1) expression in both human and rat HSCs by directly binding to its 3' untranslated region. Importantly, TAB1 expression was significantly elevated during liver fibrogenesis and HSC activation. Knockdown of TAB1 inhibited the proliferation and fibrogenic behavior of HSCs, and significantly reduced the effect of the miR-134 inhibitor on HSC proliferation. Collectively, these data suggest that miR-134 inhibits the activation of HSCs via directly targeting TAB1, and the restoration of miR-134 or targeting TAB1 is of clinical significance in the treatment of liver fibrosis.

HNF1α Controls Liver Lipid Metabolism and Insulin Resistance via Negatively Regulating the SOCS-3-STAT3 Signaling Pathway

This study is aimed at evaluating the effects, functions, and mechanism of HNF1α on hepatic glycolipid metabolism. In this study, free fatty acid- (FFA-) induced steatosis of hepatocyte liver cell LO2 was used as an in vitro model. The methods of Oil Red O staining, RT-qPCR, western blot, and immunofluorescence staining were used to detect LO2-regulated HNF1α expression and its effects on FFA-induced LO2 cell steatosis, the insulin signaling and SOCS-3-STAT3 signaling pathways, the expression of lipid metabolism-related regulators, and phosphorylation. With increased FFA induction time, the expression of HNF1α in the LO2 fatty degeneration hepatic cells gradually decreased. Downregulation of HNF1α expression aggravated FFA-induced steatosis of LO2 hepatocytes. HNF1α promotes activation of the insulin pathway and oxidative breakdown of fat and inhibits lipid anabolism. Inhibitors of STAT3 can reverse the regulation of decreased HNF1α expression on the insulin signaling pathway and fat metabolism. We also confirmed this pathway using HNF1α-/- mice combining treatment with STAT3 inhibitor NSC 74859 in vivo. HNF1α regulates hepatic lipid metabolism by promoting the expression of SOCS-3 and negatively regulating the STAT3 signaling pathway.

Knockout of microRNA-21 attenuates alcoholic hepatitis through the VHL/NF-κB signaling pathway in hepatic stellate cells

microRNA-21 (miRNA) is one of the most abundant miRNAs in chronic liver injuries including alcoholic liver injury. Previous studies have demonstrated that miR-21 plays a role in inflammation in the liver and functions in hepatic stellate cells (HSCs), which reside in the perisinusoidal space between sinusoidal endothelial cells and hepatocytes and regulate sinusoidal circulation. HSCs integrate cytokine-mediated inflammatory responses in the sinusoids and relay them to the liver parenchyma. Here, we showed that the activation of Von Hippel-Lindau (VHL) expression, by miR-21 knockout in vivo and anti-miR-21 or VHL overexpression in vitro, suppressed the production of proinflammatory cytokines, such as interleukin (IL)-6, monocyte chemoattractant protein-1, and IL-1β, in human HSCs during alcoholic liver injury. Sequence and functional analyses confirmed that miR-21 directly targeted the 3'-untranslated region of VHL. Immunofluorescence and real-time PCR analysis revealed that miR-21 depletion blocked NF-κB activation in human HSCs both in cultured HSCs as well as HSCs isolated from alcohol-related liver disease mice liver by laser capture microdissection. We also showed that conditioned medium from anti-miR-21-transfected HSCs suppressed human monocyte-derived THP-1 cell migration. Taken together, our study indicates that depletion of miR-21 may downregulate cytokine production in HSCs and macrophage chemotaxis during alcoholic liver injury and that the targeting of miR-21 may have therapeutic potential for preventing the progression of alcoholic liver diseases. NEW & NOTEWORTHY This study demonstrates that silencing microRNA-21 can inhibit cytokine production and inflammatory responses in human hepatic stellate cells during alcoholic liver injury and that the targeting of microR-21 in hepatic stellate cells may have therapeutic potential for prevention and treatment of alcoholic liver diseases.

SHP-1 Acts as a Tumor Suppressor in Hepatocarcinogenesis and HCC Progression

Src homology region 2 (SH2) domain-containing phosphatase 1 (SHP-1, also known as PTPN6) is a nonreceptor protein tyrosine phosphatase that acts as a negative regulator of inflammation. Emerging evidence indicates that SHP-1 plays a role in inhibiting the progression of hepatocellular carcinoma (HCC). However, the role of SHP-1 in hepatocarcinogenesis remains unknown. Here, we find that levels of SHP-1 are significantly downregulated in human HCC tissues compared with those in noncancerous tissues (P < 0.001) and inversely correlate with tumor diameters (r = -0.4130, P = 0.0002) and serum α-fetoprotein levels (P = 0.047). Reduced SHP-1 expression was associated with shorter overall survival of patients with HCC with HBV infection. Overexpression of SHP-1 suppressed proliferation, migration, invasion, and tumorigenicity of HCC cells, whereas knockdown of SHP-1 enhanced the malignant phenotype. Moreover, knockout of Ptpn6 in hepatocytes (Ptpn6^HKO ) enhanced hepatocarcinogenesis induced by diethylnitrosamine (DEN) as well as metastasis of primary liver cancer in mice. Furthermore, systemic delivery of SHP-1 by an adenovirus expression vector exerted a therapeutic effect in an orthotopic model of HCC in NOD/SCID mice and DEN-induced primary liver cancers in Ptpn6^HKO mice. In addition, SHP-1 inhibited the activation of JAK/STAT, NF-κB, and AKT signaling pathways, but not the MAPK pathway in primary hepatocytes from DEN-treated mice and human HCC cells. Together, our data implicate SHP-1 as a tumor suppressor of hepatocarcinogenesis and HCC progression and propose it as a novel prognostic biomarker and therapeutic target of HCC.Significance: The nonreceptor protein tyrosine phosphatase SHP-1 acts as a tumor suppressor in hepatocellular carcinoma. Cancer Res; 78(16); 4680-91. ©2018 AACR.

Oncogenic miR-425-5p is associated with cellular migration, proliferation and apoptosis in renal cell carcinoma

An increasing number of studies have demonstrated the function of microRNAs (miRNAs) in the initiation and development of various types of cancer. Among them, miR-425-5p is proven to serve an important function in several types of cancer, including gastric, cervical cancer, and hepatocellular carcinoma. However, the function of miR-425-5p in renal cell carcinoma (RCC) remains unclear. In the present study, it was demonstrated that the expression level of miR-425-5p was upregulated in RCC tissues and cell lines compared with normal tissues and cell lines (P<0.05). Additionally, Cell Counting kit-8 and MTT assays were employed to assess cell viability and proliferation, whereas wound healing and Transwell assays were employed to examine migration and invasion. The results demonstrated that upregulation of miR-425-5p promoted cell viability and the invasion and migration of ACHN and 786O cells (P<0.05). Flow cytometric analysis confirmed that upregulation of miR-425-5p inhibited apoptosis of ACHN and 786O cells (P<0.05). Downregulation of miR-425-5p inhibited the viability and invasion and migration of ACHN and 786O cells (P<0.05). In the present study, upregulation of miR-425-5p inhibited apoptosis of ACHN and 786O cells whereas no differences in early apoptotic rate were observed between the inhibitor and inhibitor NC groups for 786O and ACHN cells. These results indicate that miR-425-5p may act as an oncogene in RCC.

The HNF1α-regulated lncRNA HNF1A-AS1 reverses the malignancy of hepatocellular carcinoma by enhancing the phosphatase activity of SHP-1

BACKGROUND

Our previous study has demonstrated that hepatocyte nuclear factor 1α (HNF1α) exerts potent therapeutic effects on hepatocellular carcinoma (HCC). However, the molecular mechanisms by which HNF1α reverses HCC malignancy need to be further elucidated.

METHODS

lncRNA microarray was performed to identify the long noncoding RNAs (lncRNAs) regulated by HNF1α. Chromatin immunoprecipitation and luciferase reporter assays were applied to clarify the mechanism of the transcriptional regulation of HNF1α to HNF1A antisense RNA 1 (HNF1A-AS1). The effect of HNF1A-AS1 on HCC malignancy was evaluated in vitro and in vivo. RNA pulldown, RNA-binding protein immunoprecipitation and the Bio-Layer Interferometry assay were used to validate the interaction of HNF1A-AS1 and Src homology region 2 domain-containing phosphatase 1 (SHP-1).

RESULTS

HNF1α regulated the expression of a subset of lncRNAs in HCC cells. Among these lncRNAs, the expression levels of HNF1A-AS1 were notably correlated with HNF1α levels in HCC cells and human HCC tissues. HNF1α activated the transcription of HNF1A-AS1 by directly binding to its promoter region. HNF1A-AS1 inhibited the growth and the metastasis of HCC cells in vitro and in vivo. Moreover, knockdown of HNF1A-AS1 reversed the suppressive effects of HNF1α on the migration and invasion of HCC cells. Importantly, HNF1A-AS1 directly bound to the C-terminal of SHP-1 with a high binding affinity (KD = 59.57 ± 14.29 nM) and increased the phosphatase activity of SHP-1. Inhibition of SHP-1 enzymatic activity substantially reversed the HNF1α- or HNF1A-AS1-induced reduction on the metastatic property of HCC cells.

CONCLUSIONS

Our data revealed that HNF1A-AS1 is a direct transactivation target of HNF1α in HCC cells and involved in the anti-HCC effect of HNF1α. HNF1A-AS1 functions as phosphatase activator through the direct interaction with SHP-1. These findings suggest that regulation of the HNF1α/HNF1A-AS1/SHP-1 axis may have beneficial effects in the treatment of HCC.