Gli2-regulated activation of hepatic stellate cells and liver fibrosis by TGF-β signaling

Cancer-associated fibroblasts induce almonertinib resistance in non-small cell lung cancer

BACKGROUND

Almonertinib is the initial third-generation EGFR-TKI in China, but its resistance mechanism is unknown. Cancer-associated fibroblasts (CAFs) are essential matrix components in the tumor microenvironment, but their impact on almonertinib resistance is unknown. This study aimed to explore the correlation between CAFs and almonertinib resistance in non-small cell lung cancer (NSCLC).

METHODS

The anti-cancer effects of almonertinib on NSCLC cells, as well as the reversal of these effects mediated by CAFs, were validated through phenotypic experiments. Differential gene expression analysis, along with GO and KEGG enrichment analyses, was performed to predict the potential mechanisms underlying resistance to third-generation EGFR-TKIs. Finally, qPCR and Western blot analyses were used to explore the signaling pathways by which CAFs induce resistance to almonertinib in NSCLC cells.

RESULTS

Our findings revealed that almonertinib significantly suppressed the invasion, migration, and proliferation of EGFR T790M-mutant NSCLC cells. TGF-β1 successfully induced the differentiation of CAFs and upregulated the expression of CAF markers, including α-SMA and fibroblast activation protein (FAP). Exposure of H1975 cells to almonertinib increased TGF-β1 secretion. Additionally, CAFs enhanced the survival of almonertinib-treated NSCLC cells, whereas normal fibroblasts (NFs) exerted the opposite effect. qPCR analysis demonstrated that the expression of the core molecules of the Hippo pathway, YAP and TAZ, was lower in A549 cells than in H1975 cells, and CAF intervention further reduced YAP/TAZ expression in H1975 cells. Western blot analysis confirmed a significant reduction in YAP/TAZ protein levels in cancer cells treated with CAF-conditioned medium (CAF-CM) compared to those treated with normal control-conditioned medium (NC-CM). Finally, we demonstrated that CAFs induced resistance to almonertinib in NSCLC cells, potentially through a mechanism involving YAP/TAZ.

CONCLUSION

This study demonstrated that H1975 cells stimulated by almonertinib promoted the accumulation of CAFs in NSCLC cells, likely through increased secretion of TGF-β1. The accumulation of CAFs enhanced the survival of NSCLC cells undergoing almonertinib treatment and induced drug resistance. Additionally, the mechanism underlying CAF-induced drug resistance in NSCLC cells was potentially linked to the activation of the YAP/TAZ signaling pathway.

IGF2BP3 modified GLI2 transcriptionally regulates SYVN1 and facilitates sepsis liver injury through autophagy

Autophagy enhancement in septic liver injury can play a protective role. Nerveless, the mechanism of autophagy-mediated septic liver injury needs further investigation. Our study demonstrated that in septic condition, GLI Family Zinc Finger 2 (GLI2) was elevated, whereas peroxisome-proliferator-activated receptor α (PPARα) was downregulated. Suppressing GLI2 or synovialapoptosis inhibitor 1 (SYVN1) in LPS-exposed cells increased PPARα levels, enhanced cell viability and autophagy, while inhibiting apoptosis. LPS enhanced the GLI2-SYVN1 promoter binding. SYVN1 fostered ubiquitin-mediated degradation of PPARα. IGF2BP3 stabilized GLI2 mRNA by targeting its m6A site. Silencing IGF2BP3 led to decreased GLI2 and SYVN1 but increased PPARα levels, promoting cell survival and autophagy, while repressing apoptosis. This was counteracted by SYVN1 overexpression. In cecal ligation and puncture mice, IGF2BP3, SYVN1, or GLI2 knockdown ameliorated liver damage and augmented autophagy. In summary, IGF2BP3 enhanced GLI2 stability, overexpressed GLI2 subsequent promoted SYVN1 levels by interacting with its promoter, leading to ubiquitinated degradation of PPARα, thereby inhibiting PPARα-mediated autophagy and then exacerbating liver injury in sepsis.

Dibutyl phthalate (DBP) promotes Epithelial-Mesenchymal Transition (EMT) to aggravate liver fibrosis into cirrhosis and portal hypertension (PHT) via ROS/TGF-β1/Snail-1 signalling pathway in adult rats

OBJECTIVE

The primary objective of this study was to investigate the toxicological impact of Dibutyl phthalate (DBP) on the process of liver fibrosis transitioning into cirrhosis and the subsequent development of portal hypertension (PHT) through the mechanism of epithelial-mesenchymal transition (EMT) mediated by the ROS/TGF-β/Snail-1 signaling pathway.

METHOD

Carbon tetrachloride (CCl4) (1 mg/kg) was introduced in adult rats by oral feeding in CCl4 and CCl4+DBP groups twice a week for 8 weeks, and twice for another 8 week in CCl4 group. DBP was introduced by oral feeding in the CCl4+DBP group twice over the following 8 weeks. We subsequently analyzed hemodynamics measurements and liver cirrhosis degree, hepatic inflammation and liver function in the different groups. EMT related genes expression in rats in the groups of Control, DBP, CCl4 and CCl4+DBP were measured by immunohistochemistry (IHC). Enzyme-linked immunosorbent Assay (ELISA), qRT-PCR, western blot were used to detect the EMT related proteins and mRNA gene expression levels in rats and primary hepatocytes (PHCs). Reactive oxygen species (ROS) were examined with a ROS detection kit.

RESULTS

The results showed that the CCl4+DBP group had higher portal pressure (PP) and lower mean arterial pressure (MAP) than the other groups. Elevated collagen deposition, profibrotic factor, inflammation, EMT levels were detected in DBP and CCl4+DBP groups. ROS, TGF-β1 and Snail-1 were highly expressed after DBP exposure in vitro. TGF-β1 had the potential to regulate Snail-1, and both of them were subject to regulation by ROS.

CONCLUSION

DBP could influence the progression of EMT through its toxicological effect by ROS/TGF-β1/Snail-1 signalling pathway, causing cirrhosis and PHT in final. The findings of this research might contribute to a novel comprehension of the underlying toxicological mechanisms and animal model involved in the progression of cirrhosis and PHT, and potentially offered a promising therapeutic target for the treatment of the disease.

Amphiregulin from regulatory T cells promotes liver fibrosis and insulin resistance in non-alcoholic steatohepatitis

Production of amphiregulin (Areg) by regulatory T (Treg) cells promotes repair after acute tissue injury. Here, we examined the function of Treg cells in non-alcoholic steatohepatitis (NASH), a setting of chronic liver injury. Areg-producing Treg cells were enriched in the livers of mice and humans with NASH. Deletion of Areg in Treg cells, but not in myeloid cells, reduced NASH-induced liver fibrosis. Chronic liver damage induced transcriptional changes associated with Treg cell activation. Mechanistically, Treg cell-derived Areg activated pro-fibrotic transcriptional programs in hepatic stellate cells via epidermal growth factor receptor (EGFR) signaling. Deletion of Areg in Treg cells protected mice from NASH-dependent glucose intolerance, which also was dependent on EGFR signaling on hepatic stellate cells. Areg from Treg cells promoted hepatocyte gluconeogenesis through hepatocyte detection of hepatic stellate cell-derived interleukin-6. Our findings reveal a maladaptive role for Treg cell-mediated tissue repair functions in chronic liver disease and link liver damage to NASH-dependent glucose intolerance.

MicroRNA-122-5p alleviates endometrial fibrosis via inhibiting the TGF-β/SMAD pathway in Asherman's syndrome

RESEARCH QUESTION

What is the effect of miR-122 on the progression and recovery of fibrosis in Asherman's syndrome?

DESIGN

Endometrial tissue was collected from 21 patients, 11 with intrauterine adhesion (IUA) and 10 without IUA. Quantitative real-time polymerase chain reaction, immunofluorescence and Western blot were applied to observe the expression of mRNAs/miRNAs and protein, respectively. The endometrial physical injury was carried out in C57BL/6 mice to create an endometrial fibrosis model, with intrauterine injection of adenovirus to compare the antifibrosis and repair function of miR-122 on endometrium. The morphology of the uterus was observed using haematoxylin and eosin staining, and fibrosis markers were detected by immunohistochemistry.

RESULTS

miR-122 expression was reduced in patients with IUAs, accompanied by fibrosis. MiR-122 overexpression reduced the degree of fibrosis in endometrial stromal cells. Further molecular analyses demonstrated that miR-122 inhibited fibrosis through the TGF-β/SMAD pathway by directly targeting the 3' untranslated region of SMAD family member 3, suppressing its expression. Notably, miR-122 promoted endometrial regeneration and recovery of pregnancy capacity in a mouse endometrial injury model.

CONCLUSIONS

miR-122 is a critical regulator for repair of endometrial fibrosis and provided new insight for the clinical treatment of intrauterine adhesions.

Therapeutic implications of targeting autophagy and TGF-β crosstalk for the treatment of liver fibrosis

Liver fibrosis is characterized by the excessive deposition and accumulation of extracellular matrix components, mainly collagens, and occurs in response to a broad spectrum of triggers with different etiologies. Under stress conditions, autophagy serves as a highly conserved homeostatic system for cell survival and is importantly involved in various biological processes. Transforming growth factor-β1 (TGF-β1) has emerged as a central cytokine in hepatic stellate cell (HSC) activation and is the main mediator of liver fibrosis. A growing body of evidence from preclinical and clinical studies suggests that TGF-β1 regulates autophagy, a process that affects various essential (patho)physiological aspects related to liver fibrosis. This review comprehensively highlights recent advances in our understanding of cellular and molecular mechanisms of autophagy, its regulation by TGF-β, and the implication of autophagy in the pathogenesis of progressive liver disorders. Moreover, we evaluated crosstalk between autophagy and TGF-β1 signalling and discussed whether simultaneous inhibition of these pathways could represent a novel approach to improve the efficacy of anti-fibrotic therapy in the treatment of liver fibrosis.

An inducible model for genetic manipulation and fate-tracing of PDGFRβ-expressing fibrogenic cells in the liver

Myofibroblasts are the source of extracellular matrix protein during liver fibrogenesis. Fibroblasts, hepatic stellate cells (HSCs) and vascular smooth muscle cells are mesenchymal subpopulations in the liver that are characterized by the expression of PDGFRβ and contribute to the pool of these myofibroblasts. Conditional knockout models are important to better understand the function of specific liver cell populations including mesenchymal cells. While there is a limited number of constitutive mouse models for liver mesenchymal cell specific transgene expression, there is no established model for inducible gene targeting in HSCs or PDGFRβ-expressing mesenchymal cell populations in the liver. To address this, we investigated whether the tamoxifen inducible PDGFRβ-P2A-CreER^T2 mouse can be used as a reliable tool to specifically express transgens in liver mesenchymal cells. Our data demonstrate, that PDGFRβ-P2A-CreER^T2 specifically and efficiently marks over 90% of retinoid positive HSCs in healthy and fibrotic liver in mice upon tamoxifen injection, and that those cells give rise to Col1a1-expressing myofibroblasts in different models of liver fibrosis. Together with a negligible background recombination of only about 0.33%, this confirms that the PDGFRβ-P2A-CreER^T2 mouse is nearly as efficient as established constitutive LratCre and PDGFRβ-Cre mouse models for recombination in HSCs, and that it is a powerful model for mesenchymal liver cell studies that require an inducible Cre approach.

Small-molecule natural plants for reversing liver fibrosis based on modulation of hepatic stellate cells activation: An update

BACKGROUND

Liver fibrosis (LF) is a trauma repair process carried out by the liver in response to various acute and chronic liver injuries. Its primary pathological characteristics are excessive proliferation and improper dismissal of the extracellular matrix, and if left untreated, it will progress into cirrhosis, liver cancer, and other diseases. Hepatic stellate cells (HSCs) activation is intimately associated to the onset of LF, and it is anticipated that addressing HSCs proliferation can reverse LF. Plant-based small-molecule medications have anti-LF properties, and their mechanisms of action involve suppression of extracellular matrix abnormally accumulating as well as anti-inflammation and anti-oxidative stress. New targeting HSC agents will therefore be needed to provide a potential curative response.

PURPOSE

The most recent HSC routes and small molecule natural plants that target HSC described domestically and internationally in recent years were examined in this review.

METHODS

The data was looked up using resources including ScienceDirect, CNKI, Web of Science, and PubMed. Keyword searches for information on hepatic stellate cells included "liver fibrosis", "natural plant", "hepatic stellate cells", "adverse reaction", "toxicity", etc. RESULTS: We discovered that plant monomers can target and control various pathways to prevent the activation and proliferation of HSC and promote the apoptosis of HSC in order to achieve the anti-LF effect in this work by compiling the plant monomers that influence many common pathways of HSC in recent years. It demonstrates the wide-ranging potential of plant monomers targeting different routes to combat LF, with a view to supplying new concepts and new strategies for natural plant therapy of LF as well as research and development of novel pharmaceuticals. The investigation of kaempferol, physalin B, and other plant monomers additionally motivated researchers to focus on the structure-activity link between the main chemicals and LF.

CONCLUSION

The creation of novel pharmaceuticals can benefit greatly from the use of natural components. They are often harmless for people, non-target creatures, and the environment because they are found in nature, and they can be employed as the starting chemicals for the creation of novel medications. Natural plants are valuable resources for creating new medications with fresh action targets because they feature original and distinctive action mechanisms.

Signaling Pathways and Genes Associated with Hexavalent Chromium-Induced Hepatotoxicity

Exposure to hexavalent chromium [Cr(VI)] causes human and animal hepatotoxicity. However, it is unclear how Cr(VI) induces hepatotoxicity, nor is it clear which pathways and genes may be involved. This study aimed to identify the key molecular pathways and genes engaged in Cr(VI)-induced hepatotoxicity. Publicly available microarray GSE19662 was downloaded from the Gene Expression Omnibus database. GSE19662 consists of primary rat hepatocyte (PRH) groups treated with or without 0.10 ppm potassium dichromate (PD), with three samples per group. Compared to the control group, a total of 400 differentially expressed genes were obtained. Specially 262 and 138 genes were up- and downregulated in PD-treated PRHs, respectively. Gene ontology (GO) enrichment indicated that those DEGs were primarily engaged in many biological processes, including androgen biosynthetic process, the positive regulation of cell death, the response to activity, the toxic substance and hepatocyte growth factor stimulus, and others. Kyoto Encyclopedia of Genes and Genomes (KEGG) suggested that the DEGs are fundamentally enriched in hepatocellular carcinoma (HCC), hepatitis B, p53, PI3K-Akt, MAPK, AMPK, metabolic pathways, estrogen, cGMP-PKG, metabolic pathways, etc. Moreover, many genes, including UBE2C, TOP2A, PRC1, CENPF, and MKI67, might contribute to Cr(VI)-induced hepatotoxicity. Taken together, this study enhances our understanding of the regulation, prevention, and treatment strategies of Cr(VI)-induced hepatotoxicity.

Pantoprazole ameliorates liver fibrosis and suppresses hepatic stellate cell activation in bile duct ligation rats by promoting YAP degradation

Liver fibrosis is one of the most severe pathologic consequences of chronic liver diseases, and effective therapeutic strategies are urgently needed. Proton pump inhibitors (PPIs) are H⁺/K⁺-ATPase inhibitors and currently used to treat acid-related diseases such as gastric ulcers, which have shown other therapeutic effects in addition to inhibiting acid secretion. However, few studies have focused on PPIs from the perspective of inhibiting hepatic fibrosis. In the present study, we investigated the effects of pantoprazole (PPZ), a PPI, against liver fibrosis in a bile duct ligation (BDL) rat model, human hepatic stellate cell (HSC) line LX-2 and mouse primary HSCs (pHSCs), and explored the potential mechanisms underlying the effects of PPZ in vitro and in vivo. In BDL rats, administration of PPZ (150 mg· kg^-1· d^-1, i.p. for 14 d) significantly attenuated liver histopathological injury, collagen accumulation, and inflammatory responses, and suppressed fibrogenesis-associated gene expression including Col1a1, Acta2, Tgfβ1, and Mmp-2. In LX-2 cells and mouse pHSCs, PPZ (100-300 μM) dose-dependently suppressed the levels of fibrogenic markers. We conducted transcriptome analysis and subsequent validation in PPZ-treated LX-2 cells, and revealed that PPZ inhibited the expression of Yes-associated protein (YAP) and its downstream targets such as CTGF, ID1, survivin, CYR61, and GLI2. Using YAP overexpression and silencing, we demonstrated that PPZ downregulated hepatic fibrogenic gene expression via YAP. Furthermore, we showed that PPZ promoted the proteasome-dependent degradation and ubiquitination of YAP, thus inhibiting HSC activation. Additionally, we showed that PPZ destabilized YAP by disrupting the interaction between a deubiquitinating enzyme OTUB2 and YAP, and subsequently blocked the progression of hepatic fibrosis.