Relationship between transforming growth factor β1 and anti-fibrotic effect of interleukin-10

Pancreatic stellate cells: Key players in pancreatic health and diseases (Review)

As a pluripotent cell, activated pancreatic stellate cells (PSCs) can differentiate into various pancreatic parenchymal cells and participate in the secretion of extracellular matrix and the repair of pancreatic damage. Additionally, PSCs characteristics allow them to contribute to pancreatic inflammation and carcinogenesis. Moreover, a detailed study of the pathogenesis of activated PSCs in pancreatic disease can offer promise for the development of innovative therapeutic strategies and improved patient prognoses. Therefore, the present study review aimed to examine the involvement of activated PSCs in pancreatic diseases and elucidate the underlying mechanisms to provide a viable therapeutic strategy for the management of pancreas‑related diseases.

Macrophages-microenvironment crosstalk in fibrostenotic inflammatory bowel disease: from basic mechanisms to clinical applications

INTRODUCTION

Intestinal fibrosis is a common complication of Inflammatory Bowel Disease (IBD) with no available drugs. The current therapeutic principle is surgical intervention as the core. Intestinal macrophages contribute to both the progression of inflammation and fibrosis. Understanding the role of macrophages in the intestinal microenvironment could bring new hope for fibrosis prevention or even reversal.

AREAS COVERED

This article reviewed the most relevant reports on macrophage in the field of intestinal fibrosis. The authors discussed current opinions about how intestinal macrophages function and interact with surrounding mediators during inflammation resolution and fibrostenotic IBD. Based on biological mechanisms findings, authors summarized related clinical trial outcomes.

EXPERT OPINION

The plasticity of intestinal macrophages allows them to undergo dramatic alterations in their phenotypes or functions when exposed to gastrointestinal environmental stimuli. They exhibit distinct metabolic characteristics, secrete various cytokines, express unique surface markers, and transmit different signals. Nevertheless, the specific mechanism through which the intestinal macrophages contribute to intestinal fibrosis remains unclear. It should further elucidate a novel therapeutic approach by targeting macrophages, especially distinct mechanisms in specific subgroups of macrophages involved in the progression of fibrogenesis in IBD.

Recovery from Liver Failure and Fibrosis in a Rat Portacaval Anastomosis Model after Neurointermediate Pituitary Lobectomy

Liver diseases, including cirrhosis, viral hepatitis, and hepatocellular carcinoma, account for approximately two million annual deaths worldwide. They place a huge burden on the global healthcare systems, compelling researchers to find effective treatment for liver fibrosis-cirrhosis. Portacaval anastomosis (PCA) is a model of liver damage and fibrosis. Arginine vasopressin (AVP) has been implicated as a proinflammatory-profibrotic hormone. In rats, neurointermediate pituitary lobectomy (NIL) induces a permanent drop (80%) in AVP serum levels. We hypothesized that AVP deficiency (NIL-induced) may decrease liver damage and fibrosis in a rat PCA model. Male Wistar rats were divided into intact control (IC), NIL, PCA, and PCA+NIL groups. Liver function tests, liver gene relative expressions (IL-1, IL-10, TGF-β, COLL-I, MMP-9, and MMP-13), and histopathological assessments were performed. In comparison with those in the IC and PCA groups, bilirubin, protein serum, and liver glycogen levels were restored in the PCA+NIL group. NIL in the PCA animals also decreased the gene expression levels of IL-1 and COLL-I, while increasing those of IL-10, TGF-β, and MMP-13. Histopathology of this group also showed significantly decreased signs of liver damage with lower extent of collagen deposition and fibrosis. Low AVP serum levels were not enough to fully activate the AVP receptors resulting in the decreased activation of cell signaling pathways associated with proinflammatory-profibrotic responses, while activating cell molecular signaling pathways associated with an anti-inflammatory-fibrotic state. Thus, partial reversion of liver damage and fibrosis was observed. The study supports the crucial role of AVP in the inflammatory-fibrotic processes and maintenance of immune competence. The success of the AVP deficiency strategy suggests that blocking AVP receptors may be therapeutically useful to treat inflammatory-fibrotic liver diseases.

Molecular Mechanism of Pancreatic Stellate Cells Activation in Chronic Pancreatitis and Pancreatic Cancer

Activated pancreatic stellate cells (PSCs) are the main effector cells in the process of fibrosis, a major pathological feature in pancreatic diseases that including chronic pancreatitis and pancreatic cancer. During tumorigenesis, quiescent PSCs change into an active myofibroblast-like phenotype which could create a favorable tumor microenvironment and facilitate cancer progression by increasing proliferation, invasiveness and inducing treatment resistance of pancreatic cancer cells. Many cellular signals are revealed contributing to the activation of PSCs, such as transforming growth factor-β, platelet derived growth factor, mitogen-activated protein kinase (MAPK), Smads, nuclear factor-κB (NF-κB) pathways and so on. Therefore, investigating the role of these factors and signaling pathways in PSCs activation will promote the development of PSCs-specific therapeutic strategies that may provide novel options for pancreatic cancer therapy. In this review, we systematically summarize the current knowledge about PSCs activation-associated stimulating factors and signaling pathways and hope to provide new strategies for the treatment of pancreatic diseases.

CXCL6-EGFR-induced Kupffer cells secrete TGF-β1 promoting hepatic stellate cell activation via the SMAD2/BRD4/C-MYC/EZH2 pathway in liver fibrosis

Liver fibrosis is the excessive accumulation of extracellular matrix proteins in response to the inflammatory response that accompanies tissue injury, which at an advanced stage can lead to cirrhosis and even liver failure. This study investigated the role of the CXC chemokine CXCL6 (GCP‐2) in liver fibrosis. The expression of CXCL6 was found to be elevated in the serum and liver tissue of high stage liver fibrosis patients. Furthermore, treatment with CXCL6 (100 ng/mL) stimulated the phosphorylation of EGFR and the expression of TGF‐β in cultured Kupffer cells (KCs). Although treatment with CXCL6 directly did not activate the hepatic stellate cell (HSC) line, HSC‐T6, HSCs cultured with media taken from KCs treated with CXCL6 or TGF‐β showed increased expression of α‐SMA, a marker of HSC activation. CXCL6 was shown to function via the SMAD2/BRD4/C‐MYC/EZH2 pathway by enhancing the SMAD3‐BRD4 interaction and promoting direct binding of BRD4 to the C‐MYC promoter and CMY‐C to the EZH2 promoter, thereby inducing profibrogenic gene expression in HSCs, leading to activation and transdifferentiation into fibrogenic myofibroblasts. These findings were confirmed in a mouse model of CCl₄‐induced chronic liver injury and fibrosis in which the levels of CXCL6 and TGF‐β in serum and the expression of α‐SMA, SMAD3, BRD4, C‐MYC, and EZH2 in liver tissue were increased. Taken together, our results reveal that CXCL6 plays an important role in liver fibrosis through stimulating the release of TGF‐β by KCs and thereby activating HSCs.

Loureirin B inhibits the proliferation of hepatic stellate cells and the Wnt/β-catenin signaling pathway by regulating miR-148-3p

BACKGROUND

We investigated the activity of loureirin B against liver fibrosis and the underlying molecular mechanisms.

METHODS

Hepatic stellate cells (HSCs) from Sprague-Dawley rats were treated with different concentrations of loureirin B. We used the MTT assay to determine HSC proliferation, flow cytometry to analyze apoptosis, and western blot to determine the expressions of Bax, Bcl-2, Wnt1 and β-catenin. Real-time PCR was used to determine the expressions of Wnt1 and miR-148-3p.

RESULTS

The MTT assay showed that loureirin B treatment significantly inhibited the proliferation of HSCs in time- and dose-dependent manners. Loureirin B significantly promoted the apoptosis of HSCs, increased the expression of Bax and decreased the Bcl-2 level. Western blot analysis showed that the expressions of Wnt1 and β-catenin were obviously lower in the loureirin B treatment group than in the control group. We also found that loureirin B could decrease the Wnt1 mRNA level and increase miR-148-3p expression. Knockdown of miR-148-3p using inhibitor could reverse the effects of loureirin B on the proliferation and apoptosis of HSCs and the expressions of Bax, Bcl-2, Wnt1 and β-catenin.

CONCLUSION

Our results suggest that loureirin B inhibited the proliferation and promoted the apoptosis of HSCs, and suppressed the Wnt/β-catenin signaling pathway via regulation of miR-148-3p.

Interleukin‑10 promotes primary rat hepatic stellate cell senescence by upregulating the expression levels of p53 and p21

Liver fibrosis is characterized by the excessive deposition of extracellular matrix (ECM) components, and activated hepatic stellate cells (HSCs) are a primary source of ECM. Several studies have revealed that the induction of HSC senescence may reduce liver fibrosis. The effect of interleukin-10 (IL-10) on the senescence of activated HSCs is not fully understood. Therefore, the present study examined its effects and potential mechanisms in activated primary rat HSCs. Collagenase perfusion and density gradient centrifugation methods were used to isolate rat HSCs. HSCs were identified by autofluorescence, Oil Red O staining and immunocytochemical analysis. Activated HSCs were treated with 0, 10, 20 or 40 ng/ml IL-10 for 24 h. Senescence-associated β-galactosidase (SA-β-Gal) staining, flow cytometry analysis and a cell counting kit-8 assay were performed to detect the senescence, apoptosis and viability of rat HSCs, respectively. Reverse transcription-quantitative polymerase chain reaction, western blot analysis and enzyme linked immunosorbent assays were used to detect the expression of senescence-associated proteins and cytokines. Freshly isolated rat HSCs exhibited a striking blue-green autofluorescence and HSC retinoid droplets were stained bright red by Oil Red O. Immunocytochemical analysis demonstrated the cytoplasmic expression of HSC markers desmin and α-smooth muscle actin. The number of SA-β-Gal positive HSCs, the apoptotic rate and the expression levels of p53, p21 and tumor necrosis factor-α were significantly increased following IL-10 treatment. HSC viability and IL-6 and IL-8 expression levels were significantly decreased compared with the control group. In summary, primary rat HSCs were successfully isolated and IL-10 was demonstrated to promote the senescence of activated primary rat HSCs through the upregulation of p53 and p21 expression.

Doxazosin Treatment Attenuates Carbon Tetrachloride-Induced Liver Fibrosis in Hamsters through a Decrease in Transforming Growth Factor β Secretion

Background/Aims

The development of therapeutic strategies for the treatment of cirrhosis has become an important focus for basic and clinical researchers. Adrenergic receptor antagonists have been evaluated as antifibrotic drugs in rodent models of carbon tetrachloride (CCl4)-induced cirrhosis. The aim of the present study was to evaluate the effects of carvedilol and doxazosin on fibrosis/cirrhosis in a hamster animal model.

Methods

Cirrhotic-induced hamsters were treated by daily administration of carvedilol and doxazosin for 6 weeks. Hepatic function and histological evaluation were conducted by measuring biochemical markers, including total bilirubin, aspartate aminotransferase, alanine aminotransferase and albumin, and liver tissue slices. Additionally, transforming growth factor β (TGF-β) immunohistochemistry was analyzed.

Results

Biochemical markers revealed that hepatic function was restored after treatment with doxazosin and carvedilol. Histological evaluation showed a decrease in collagen type I deposits and TGF-β-secreting cells.

Conclusions

Taken together, these results suggest that the decrease in collagen type I following treatment with doxazosin or carvedilol is achieved by decreasing the profibrotic activities of TGF-β via the blockage of α1- and β-adrenergic receptor. Consequently, a diminution of fibrotic tissue in the CCl4-induced model of cirrhosis is achieved.

Attenuation of methylglyoxal-induced peritoneal fibrosis: immunomodulation by interleukin-10

Peritoneal fibrosis (PF), a serious pathophysiology of peritoneal dialysis (PD), is implicated in various types of chronic inflammation. In the present study, we examined the benefits of interleukin (IL)-10, which exerts anti-inflammatory effects, in an experimental rat model of methylglyoxal (MGO)-induced PF. We injected an adeno-associated virus (AAV) vector encoding rat IL-10 or enhanced green fluorescent protein (GFP) into male Sprague-Dawley rats at 6 weeks of age. Four weeks later, the rats received continuous peritoneal injections of conventional PD fluid (PDF) with MGO for 3 weeks. Then, the peritoneal histology and the expression levels of fibrogenic mediators and proinflammatory cytokines were analyzed. The rats demonstrating persistent IL-10 expression showed significantly reduced fibrous peritoneal thickening compared with those with GFP expression. The infiltration of macrophages, the expression of tumor necrosis factor-α, IL-1β, IL-6, transforming growth factor-β1, Snail, and matrix metalloproteinase 2 genes as well as the proliferation of mesenchymal-like mesothelial cells augmented by MGO were all significantly suppressed by IL-10 expression. IL-10 also abrogated the extent of MGO-induced bowel adhesions mimicking a cocoon-like mass. Our findings provide valuable insight into the potential benefit of immunomodulation with IL-10 as one potentially effective therapeutic strategy for preventing the onset of peritoneal injury resulting in PF.

Inactivated ORF virus shows antifibrotic activity and inhibits human hepatitis B virus (HBV) and hepatitis C virus (HCV) replication in preclinical models

Inactivated orf virus (iORFV), strain D1701, is a potent immune modulator in various animal species. We recently demonstrated that iORFV induces strong antiviral activity in animal models of acute and chronic viral infections. In addition, we found D1701-mediated antifibrotic effects in different rat models of liver fibrosis. In the present study, we compare iORFV derived from two different strains of ORFV, D1701 and NZ2, respectively, with respect to their antifibrotic potential as well as their potential to induce an antiviral response controlling infections with the hepatotropic pathogens hepatitis C virus (HCV) and hepatitis B virus (HBV). Both strains of ORFV showed anti-viral activity against HCV in vitro and against HBV in a transgenic mouse model without signs of necro-inflammation in vivo. Our experiments suggest that the absence of liver damage is potentially mediated by iORFV-induced downregulation of antigen cross-presentation in liver sinus endothelial cells. Furthermore, both strains showed significant anti-fibrotic activity in rat models of liver fibrosis. iORFV strain NZ2 appeared more potent compared to strain D1701 with respect to both its antiviral and antifibrotic activity on the basis of dosages estimated by titration of active virus. These results show a potential therapeutic approach against two important human liver pathogens HBV and HCV that independently addresses concomitant liver fibrosis. Further studies are required to characterize the details of the mechanisms involved in this novel therapeutic principle.

Inactivated Orf virus (Parapoxvirus ovis) elicits antifibrotic activity in models of liver fibrosis

AIM

Inactivated Orf virus (ORFV, Parapoxvirus ovis) demonstrates strong antiviral activity in animal models including a human hepatitis B virus (HBV)-transgenic mouse. In addition, expression of interferon (IFN)-γ and interleukin-10 (IL-10) was induced after administration of inactivated ORFV in these mice. IFN-γ and IL-10 are known to elicit antifibrotic activity. We therefore aimed to study antifibrotic activity of inactivated ORFV in models of liver fibrosis.

METHODS

We characterized ORFV-induced hepatic cytokine expression in rats. We then studied ORFV in two models of liver fibrosis in rats, pig serum-induced liver fibrosis and carbon tetrachloride (CCL4 )-induced liver fibrosis.

RESULTS

ORFV induced hepatic expression of IFN-γ and IL-10 in rats. ORFV mediated antifibrotic activity when administrated concomitantly with the fibrosis-inducing agents in both models of liver fibrosis. Importantly, when CCL4 -induced liver fibrosis was already established, ORFV application still showed significant antifibrotic activity. In addition, we were able to demonstrate a direct antifibrotic effect of ORFV on stellate cells.

CONCLUSION

These results establish a potential novel antifibrotic therapeutic approach that not only prevents but also resolves established liver fibrosis. Further studies are required to unravel the details of the mechanisms involved.

Therapeutic immunomodulation using a virus--the potential of inactivated orf virus

Viruses can manipulate the immune response against them by various strategies to influence immune cells, i.e. by over-activation leading to functional inactivation, bypassing antigen presentation or even suppression of effector functions. Little is known, however, about how these features of immune regulation and modulation could be used for therapeutic purposes. Reasons for this include the complexity of immune regulatory mechanisms under certain disease conditions and the risks that infections with viruses pose to human beings. The orf virus (ORFV), a member of the Parapoxvirus genus of the poxvirus family, is known as a common pathogen in sheep and goats worldwide. The inactivated ORFV, however, has been used as a preventative as well as therapeutic immunomodulator in veterinary medicine in different species. Here, we review the key results obtained in pre-clinical studies or clinical studies in veterinary medicine to characterise the therapeutic potential of inactivated ORFV. Inactivated ORFV has strong effects on cytokine secretion in mice and human immune cells, leading to an auto-regulated loop of initial up-regulation of inflammatory and Th1-related cytokines, followed by Th2-related cytokines that attenuate immunopathology. The therapeutic potential of inactivated ORFV has been recognised in several difficult-to-treat disease areas, such as chronic viral diseases, liver fibrosis or various forms of cancer. Further research will be required in order to evaluate the full beneficial potential of inactivated ORFV for therapeutic immunomodulation.

Lung fibrosis induced by crystalline silica particles is uncoupled from lung inflammation in NMRI mice

Previous studies in rats have suggested a causal relationship between progressive pulmonary inflammation and lung fibrosis induced by crystalline silica particles. We report here that, in NMRI mice, the lung response to silica particles is accompanied by a mild and non progressive pulmonary inflammation which is dispensable for the development of lung fibrosis. We found that glucocorticoid (dexamethasone) dramatically reduced lung injury, cellular inflammation and pro-inflammatory cytokine expression (TNF-α, IL-1β and KC) but had no significant effect on silica-induced lung fibrosis and expression of the fibrogenic and suppressive cytokines TGF-β and IL-10 in mice. Other anti-inflammatory molecules such as the COX inhibitor piroxicam or the phosphodiesterase 5 inhibitor sildenafil also reduced lung inflammation without modifying collagen, TGF-β or IL-10 lung content. Our findings indicate that the development of lung fibrosis in silica-treated NMRI mice is not driven by inflammatory lung responses and suggest that suppressive cytokines may represent critical fibrotic factors and potential therapeutic targets in silicosis.

Functional hepatic recovery after xenotransplantation of cryopreserved fetal liver cells or soluble cell-factor administration in a cirrhotic rat model: are viable cells necessary?

BACKGROUND AND AIM

Chronic liver failure results in the decrease of the number of functioning hepatocytes. It dictates the necessity of using exogenous viable cells or/and agents that can stimulate hepatic regenerative processes. Fetal liver contains both hepatic and hematopoietic stem cells with high proliferative potential, which may replace damaged cells. Also, immature cells produce fetal-specific factors which may support the injured liver. Our aim was to test the ability of human fetal liver cells and cell-free fetal-specific factors of non-hepatic origin to stimulate recovery processes in an experimental model of carbon tetrachloride-induced cirrhosis in rats.

METHODS

Cirrhotic rats were intrasplenically injected with fetal liver cells (1 x 10(7) cells/0.3 mL medium) or cell-free fetal-specific factors (0.3 mL/1 mg protein). Control groups received medium alone. Serum indexes, hepatic functions, and morphology were evaluated for 15 days.

RESULT

Human fetal liver cell transplantation was shown to abrogate the mortality of cirrhotic animals, to improve serum markers, and to restore liver mitochondrial function and detoxification. Morphological patterns of liver recovery were observed by histology. In comparison, an injection of fetal-specific factors produced similar functional recovery, whilst a more limited liver regeneration was observed by histology.

CONCLUSIONS

The positive effects of fetal liver cell and cell-free fetal-specific factors in experimental cirrhosis may result from the presence of stage-specific factors activating hepatocellular repair.

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