Phosphodiesterase inhibition mediates matrix metalloproteinase activity and the level of collagen degradation fragments in a liver fibrosis ex vivo rat model

The Role of RECK in Hepatobiliary Neoplasia Reveals Its Therapeutic Potential in NASH

Non-alcoholic fatty liver disease (NAFLD) is a multimorbidity disorder ranging from excess accumulation of fat in the liver (steatosis) to steatohepatitis (NASH) and end-stage cirrhosis, and the development of hepatocellular carcinoma (HCC) in a subset of patients. The defining features of NASH are inflammation and progressive fibrosis. Currently, no pharmaceutical therapies are available for NAFLD, NASH and HCC; therefore, developing novel treatment strategies is desperately needed. Reversion Inducing Cysteine Rich Protein with Kazal motifs (RECK) is a well-known modifier of the extracellular matrix in hepatic remodeling and transition to HCC. More recently, its role in regulating inflammatory and fibrogenic processes has emerged. Here, we summarize the most relevant findings that extend our current understanding of RECK as a regulator of inflammation and fibrosis, and its induction as a potential strategy to blunt the development and progression of NASH and HCC.

Diosmin enhances the anti-angiogenic activity of sildenafil and pentoxifylline against hepatopulmonary syndrome via regulation of TNF-α/VEGF, IGF-1/PI3K/AKT, and FGF-1/ANG-2 signaling pathways

Hepatopulmonary syndrome (HPS) is a severe complication of hepatic cirrhosis, which is characterized by hypoxia, intrapulmonary vasodilation, inflammation, and angiogenesis. In this study, we aimed to investigate the regulatory effects of diosmin (DS) on selected phosphodiesterase inhibitors against chronic bile duct ligation (CBDL)-induced HPS. Experimentally, Wistar Albino rats were used and HPS was induced by CBDL for 28 days. DS (100 mg/kg, daily, P.O.), sildenafil (Sild; 10 mg/kg, twice daily, P.O.), and pentoxifylline (PTX; 50 mg/kg, daily, P.O.) were evaluated either alone or in combinations for their anti-angiogenic activity. CBDL significantly altered oxidative stress biomarkers and up-regulated pulmonary mRNA expressions of VEGF, IGF-1, ET-1, iNOS, eNOS, and ANG-2 as well as the protein expressions of vWF, FGF-1, PI3K, AKT, p-AKT, TGF-β, HYP, MPO activity and circulating TNF-α. Treatment with DS, Sild, PTX, and their combinations significantly attenuated molecular and cellular changes due to CBDL. Improvement of histopathological changes was also observed after drug treatment which further supported our results. Furthermore, DS combination with Sild or PTX exhibited an improvement in HPS in comparison to each drug alone. Collectively, DS can augment the anti-angiogenic activity of Sild and PTX during HPS through regulation of TNF-α/VEGF, IGF-1/PI3K/AKT, and FGF-1/ANG-2 signaling pathways.

Molecular characterization of a precision-cut rat liver slice model for the evaluation of antifibrotic compounds

Precision-cut liver tissue slice (PCLS) contains all major cell types of the liver parenchyma and preserves the original cell-cell and cell-matrix contacts. It represents a promising ex vivo model to study liver fibrosis and test the antifibrotic effect of experimental compounds in a physiological environment. In this study using RNA sequencing, we demonstrated that various pathways functionally related to fibrotic mechanisms were dysregulated in PCLSs derived from rats subjected to bile duct ligation. The activin receptor-like kinase-5 (Alk5) inhibitor SB525334, nintedanib, and sorafenib each reversed a subset of genes dysregulated in fibrotic PCLSs, and of those genes we identified 608 genes whose expression was reversed by all three compounds. These genes define a molecular signature characterizing many aspects of liver fibrosis pathology and its attenuation in the model. A panel of 12 genes and 4 secreted biomarkers including procollagen I, hyaluronic acid (HA), insulin-like growth factor binding protein 5 (IGFBP5), and WNT1-inducible signaling pathway protein 1 (WISP1) were further validated as efficacy end points for the evaluation of antifibrotic activity of experimental compounds. Finally, we showed that blockade of α_V-integrins with a small molecule inhibitor attenuated the fibrotic phenotype in the model. Overall, our results suggest that the rat fibrotic PCLS model may represent a valuable system for target validation and determining the efficacy of experimental compounds. NEW & NOTEWORTHY We investigated the antifibrotic activity of three compounds, the activin receptor-like kinase-5 (Alk5) inhibitor SB525334, nintedanib, and sorafenib, in a rat fibrotic precision-cut liver tissue slice model using RNA sequencing analysis. A panel of 12 genes and 4 secreted biomarkers including procollagen I, hyaluronic acid (HA), insulin-like growth factor binding protein 5 (IGFBP5), and WNT1-inducible signaling pathway protein 1 (WISP1) were then established as efficacy end points to validate the antifibrotic activity of the α_V-integrin inhibitor CWHM12. This study demonstrated the value of the rat fibrotic PCLS model for the evaluation of antifibrotic drugs.

The phosphodiesterase III inhibitor cilostazol protects the brain microvasculature from collagenase injury

A patient's prognosis, including mortality, after intracranial hemorrhage (ICH) is strongly related to the disruption of the blood-brain barrier caused by damage to vascular endothelial cells (ECs). We reported previously that cilostazol, a phosphodiesterase III inhibitor, ameliorated collagenase-induced ICH in a mouse model. We also reported that cilostazol protected cultured ECs in a blood-brain barrier model. However, the influence of cilostazol on vascular structure and cell morphology remains unclear. Therefore, we investigated whether cilostazol exerts protective effects on vascular structures, such as the extracellular matrix (ECM). A mouse model of collagenase-induced ICH was used to observe structures of the brain vasculature in a peri-hemorrhagic lesion using transmission electron microscopy. We then evaluated the morphology of the ECM and cytoskeleton in human brain microvasculature ECs by immunostaining. The brain vasculature was changed 24 h after induction of ICH. Cilostazol (30 mg/kg, orally) suppressed the thinning of the basement membrane, which is formed by the ECM components collagen IV and laminin. Moreover, this drug also suppressed the enlargement of ECs caused by ICH. Collagenase treatment (30 U/ml) of human brain microvasculature ECs caused a decrease in collagen IV expression and an increase in the number and size of the intercellular spaces, as indicated by β-actin immunostaining. Pretreatment of with 10 µM cilostazol suppressed these increases in the number and size of the intercellular spaces. These findings suggest that cilostazol protects the ECM of the brain microvasculature against ICH both in vivo and in vitro.

Panax notoginseng saponins ameliorates experimental hepatic fibrosis and hepatic stellate cell proliferation by inhibiting the Jak2/ Stat3 pathways

OBJECTIVE

To investigate the inhibitory effect of Panax notoginseng saponins (PNS) on liver fibrosis and explore the underlying mechanisms.

METHODS

Carbon tetrachloride (CCl4)-treated rats and hepatic stellate cells (HSCs) were used. The effect of PNS on CCl4-induced liver fibrosis was studied with histochemical and biochemical analysis. Transforming growth factor (TGF)-β1, α-smooth muscle actin (α-SMA), and collagen I mRNA expression were determined by reverse transcripwhile, the protein expression levels of α-SMA, collagen I, phosphorylation-Janus activated kinase signal transducer (p-Jak2)/Jak2, and phosphorylation-activator of transcription (p-Stat)3/Stat3 were determined by immunohistochemistry and/or immunoblotting.

RESULTS

PNS treatment significantly improved the liver function of rats as indicated by decreased serum enzymatic activities of alanine aminotransferase and aspartate aminotransferase. Histopathological results indicated that PNS alleviated liver damage and reduced the formation of fibrous septa. Moreover, PNS significantly decreased liver hydroxyproline and significantly attenuated expressions of collagen I, α-SMA, TGF-β1, p-Jak2 / Jak2, and p-Stat3/Stat3 in the rat liver fibrosis model and HSCs.

CONCLUSION

PNS can relieve liver fibrosis by modulating Jak2/Stat3 signaling transduction pathway, which may be one of its mechanisms to suppress hepatic fibrosis.

Tissue turnover of collagen type I, III and elastin is elevated in the PCLS model of IPF and can be restored back to vehicle levels using a phosphodiesterase inhibitor

BACKGROUND

The aim of this study was to develop and validate a model for pulmonary fibrosis, using ex vivo tissue cultures of lungs from bleomycin treated animals, enabling the investigation of fibrosis remodeling using novel biomarkers for the detection of ECM protein fragments. The combination of in vivo and ex vivo models together with ECM remodeling markers may provide a translational tool for screening of potential treatments for IPF.

METHODS

Twenty female Sprague-Dawley rats, twelve weeks of age, were administrated either two doses of bleomycin (BLM) (n = 14) or saline (n = 6) I.T., two days apart. Ten rats were euthanized at day seven and the remaining ten rats at day fourteen, after the last dose. Precision-cut lung slices (PCLS) were made and cultured for 48 h. Ten female Sprague-Dawley rats, twelve weeks of age, were administrated either two doses of BLM (n = 7) or saline (n = 3) I.T., two days apart. The rats were euthanized fourteen days after the last dose. PCLS were made and cultured for 48 h in: medium, medium + 100 μM IBMX (PDE inhibitor), or medium + 10 μM GM6001 (MMP inhibitor). Turnover of type I collagen (P1NP, C1M), type III collagen (iP3NP, C3M) and elastin degradation (ELM7) was measured in the supernatant of the cultured PCLS.

RESULTS

P1NP, C1M, iP3NP, C3M and ELM7 were significantly increased in supernatants from BLM animals (P ≤ 0.05 - P ≤ 0.0001) when compared to controls. P1NP, C1M, iP3NP, C3M and ELM7 were significantly increased in supernatants from day seven BLM animals compared to day fourteen BLM animals (P ≤ 0.05 - P ≤ 0.0001). P1NP, C1M, iP3NP, C3M and ELM7 were significantly decreased when adding IBMX to the culture medium of fibrotic lung tissue (P ≤ 0.05 - P ≤ 0.0001). C1M, C3M and ELM7 were significantly decreased when adding GM6001 to the culture medium (P ≤ 0.05 - P ≤ 0.0001). Sirius Red and Orcein staining confirmed the presence of collagen and elastin deposition in the lungs of the animals receiving BLM.

CONCLUSIONS

The protein fingerprint technology allows the assessment of ECM remodeling markers in the BLM PCLS model. By combining in vivo, ex vivo models and the protein fingerprint technology in the fibrotic phase of the model, we believe the chance of translation from animal model to human is markedly increased.

Precision-Cut Kidney Slices as a Tool to Understand the Dynamics of Extracellular Matrix Remodeling in Renal Fibrosis

The aim of this study was to set up an ex vivo model for renal interstitial fibrosis in order to investigate the extracellular matrix (ECM) turnover profile in the fibrotic kidney. We induced kidney fibrosis in fourteen 12-week-old male Sprague Dawley rats by unilateral ureteral obstruction (UUO) surgery of the right ureter. The left kidney (contralateral) was used as internal control. Six rats were sham operated and used as the control group. Rats were terminated two weeks after the surgery; the kidneys were excised and precision-cut kidney slices (PCKSs) were cultured for five days in serum-free medium. Markers of collagen type I formation (P1NP), collagen type I and III degradation (C1M and C3M), and α-smooth muscle actin (αSMA) were measured in the PCKS supernatants by enzyme-linked immunosorbent assay. P1NP, C1M, C3M, and α-SMA were increased up to 2- to 13-fold in supernatants of tissue slices from the UUO-ligated kidneys compared with the contralateral kidneys (P < 0.001) and with the kidneys of sham-operated animals (P < 0.0001). The markers could also reflect the level of fibrosis in different animals. The UUO PCKS ex vivo model provides a valuable translational tool for investigating the extracellular matrix remodeling associated with renal interstitial fibrosis.

Pathological Roles of Interleukin-22 in the Development of Recurrent Hepatitis C after Liver Transplantation

OBJECTIVE

The aim of this study was to longitudinally evaluate and analyze the role of interleukin-22-producing CD4 positive cells (IL-22) in the pathogenesis of Hepatitis C Virus recurrence after Orthotopic Liver Transplantation (HCV-OLT).

METHODS

15 HCV-OLT, 15 age- and gender- matched non-HCV post-OLT (OLT) and 15 hepatitis C virus infected (HCV) patients were enrolled into our study from the liver transplantation and research center at Beijing 302 Hospital. We determined the frequencies of IL-22 using flow cytometry and expression of IL-22 mRNA using PCR in peripheral blood and liver tissue. We also divided HCV-OLT patients into rapid fibrosis progression (RFP) and slow fibrosis progression (SFP), examined IL-22 cells and analyzed the correlations between IL-22 frequencies and liver injury, fibrosis and clinical parameters. Moreover, we investigated the role of IL-22 in Human Hepatic Stellate Cells (HSCs).

RESULTS

The levels of serum IL-22, frequencies of IL-22 producing cells in peripheral blood mononuclear cells, and expression of IL-22 mRNA and protein in the liver in the HCV-OLT group were significantly higher than that in the HCV and OLT groups. Furthermore, eight (53.3%) patients developed RFP after two years; another three patients were diagnosed liver cirrhosis. The frequencies of IL-22 were much higher in RFP compared with SFP, while no significant difference existed between OLT and SFP. Intrahepatic IL-22 positive cells were located in fibrotic areas and significantly correlated with α-smooth muscle actin (α-SMA) and fibrosis staging scores, not with grading scores and HCRVNA. In vitro, IL-22 administration prevented HSCs apoptosis, promoted HSCs proliferation and activation, up-regulated the expression of HSC-sourced growth factors including α-SMA, TGF-β and TIMP-1, and increased the production of liver fibrosis markers including laminin, hyaluronic acid and collagen type IV.

CONCLUSION

Peripheral and intrahepatic IL-22 is up-regulated and plays a pathological role in exacerbating liver fibrosis by activating HSCs in HCV-OLT patients, which may predict RFP and serve as an attractive target for anti-fibrotic therapy.

MicroRNA-34a Promotes Hepatic Stellate Cell Activation via Targeting ACSL1

BACKGROUND

The incidence of liver fibrosis remains high due to the lack of effective therapies. Our previous work found that microRNA (miR)-34a expression was increased, while acy1-CoA synthetase long-chain family member1 (ACSL1) was decreased, in a dimethylnitrosamine (DNS)-induced hepatic fibrosis rat model. We hypothesized that miR-34a may play a role in the process of hepatic fibrosis by targeting ACSL1.

MATERIAL AND METHODS

From days 2 to 14, cultured primary hepatic stellate cells (HSCs) underwent cell morphology, immunocytochemical staining, and quantitative reverse transcription PCR (RT-qPCR) for alpha smooth muscle actin (a-SMA), desmin, rno-miR-34a, and ACSL1 expression. Wild-type and mutant luciferase reporter plasmids were constructed according to the predicted miR-34a binding site on the 3'-untranslated region (UTR) of the ACSL1 mRNA and then transfected into HEK293 cells. rno-miR-34a was silenced in HSCs to confirm that rno-miR-34a negatively regulates ACSL1 expression. mRNA and protein expression of α-SMA, type I collagen, and desmin were assayed in miR-34a-silenced HSCs.

RESULTS

HSCs were deemed quiescent during the first 3 days and activated after 10 days. rno-miR-34a expression increased, and ACSL1 expression decreased, from day 2 to 7 to 14. rno-miR-34a was shown to specifically bind to the 3'-UTR of ACSL1. miR-34a-silenced HSCs showed higher ACSL1and lower α-SMA, type I collagen, and desmin expression than that of matching negative controls and non-transfected cells.

CONCLUSIONS

miR-34a appears to play an important role in the process of liver fibrosis by targeting ACSL1 and may show promise as a therapeutic molecular target for hepatic fibrosis.

Novel insights into the function and dynamics of extracellular matrix in liver fibrosis

Emerging evidence suggests that altered components and posttranslational modifications of proteins in the extracellular matrix (ECM) may both initiate and drive disease progression. The ECM is a complex grid consisting of multiple proteins, most of which play a vital role in containing the essential information needed for maintenance of a sophisticated structure anchoring the cells and sustaining normal function of tissues. Therefore, the matrix itself may be considered as a paracrine/endocrine entity, with more complex functions than previously appreciated. The aims of this review are to 1) explore key structural and functional components of the ECM as exemplified by monogenetic disorders leading to severe pathologies, 2) discuss selected pathological posttranslational modifications of ECM proteins resulting in altered functional (signaling) properties from the original structural proteins, and 3) discuss how these findings support the novel concept that an increasing number of components of the ECM harbor signaling functions that can modulate fibrotic liver disease. The ECM entails functions in addition to anchoring cells and modulating their migratory behavior. Key ECM components and their posttranslational modifications often harbor multiple domains with different signaling potential, in particular when modified during inflammation or wound healing. This signaling by the ECM should be considered a paracrine/endocrine function, as it affects cell phenotype, function, fate, and finally tissue homeostasis. These properties should be exploited to establish novel biochemical markers and antifibrotic treatment strategies for liver fibrosis as well as other fibrotic diseases.

Hedgehog signaling pathway as key player in liver fibrosis: new insights and perspectives

INTRODUCTION

Activation of hepatic stellate cells (HSCs) is a pivotal cellular event in liver fibrosis. Therefore, improving our understanding of the molecular pathways that are involved in these processes is essential to generate new therapies for liver fibrosis. Greater knowledge of the role of the hedgehog signaling pathway in liver fibrosis could improve understanding of the liver fibrosis pathogenesis.

AREAS COVERED

The aim of this review is to describe the present knowledge about the hedgehog signaling pathway, which significantly participates in liver fibrosis and HSC activation, and look ahead on new perspectives of hedgehog signaling pathway research. Moreover, we will discuss the different interactions with hedgehog signaling pathway-regulated liver fibrosis.

EXPERT OPINION

The hedgehog pathway modulates several important aspects of function, including cell proliferation, activation and differentiation. Targeting the hedgehog pathway can be a promising direction in liver fibrosis treatment. We discuss new perspectives of hedgehog signaling pathway activation in liver fibrosis and HSC fate, including DNA methylation, methyl CpG binding protein 2, microRNA, irradiation and metabolism that influence hedgehog signaling pathway transduction. These findings identify the hedgehog pathway as a potentially important for biomarker development and therapeutic targets in liver fibrosis. Future studies are needed in order to find safer and more effective hedgehog-based drugs.

Changes in matrix metalloproteinase-9 levels during progression of atrial fibrillation

OBJECTIVES

To observe levels of matrix metalloproteinase (MMP)-9 and evaluate their significance in various stages of idiopathic atrial fibrillation (AF).

METHODS

Patients with idiopathic AF were recruited into this prospective study and classified into one of three groups according to stage of disease progression: paroxysmal AF; persistent AF; permanent AF. Healthy individuals were enrolled as control subjects. Serum levels of MMP-9 in all four groups were determined using a double-antibody sandwich enzyme-linked immunosorbent assay.

RESULTS

Each AF group included 25 patients; 40 healthy individuals were included as controls. MMP-9 levels in the three AF groups were significantly higher than in the control group: 168.72 ± 25.970, 201.36 ± 31.26 and 253.20 ± 22.99 ng/ml for the paroxysmal, persistent and permanent AF groups respectively, versus 76.80 ± 14.90 ng/ml for the control group. MMP-9 levels increased with idiopathic AF disease progression (P < 0.05).

CONCLUSIONS

An elevated MMP-9 level appears to be associated with a diagnosis of AF. MMP-9 levels appear to increase in relation to the stage of idiopathic AF progression.

Interleukin-1β upregulates matrix metalloproteinase-13 gene expression via c-Jun N-terminal kinase and p38 MAPK pathways in rat hepatic stellate cells

Matrix metalloproteinase-13 (MMP-13) is crucial in the cleavage and remodeling of the extracellular matrix (ECM), and its expression levels are decreased following the induction of liver fibrosis. The aim of the present study was to investigate the role of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) in interleukin (IL)-1β-mediated MMP-13 gene expression in rat hepatic stellate cells (HSCs). In the present study, we demonstrated that IL-1β is capable of activating JNK and p38 in a time-dependent manner and the inhibition of the JNK pathway is able to increase MMP-13 mRNA expression; however, the inhibition of the p38 MAPK pathway is capable of inhibiting MMP-13 gene expression. These data demonstrate that IL-1β is able to promote MMP-13 mRNA expression in rat HSCs and the JNK and p38 MAPK pathways were involved in this process. In summary, IL-1β-induced MMP-13 mRNA expression is possibly mediated by cytoplasmic JNK and p38 MAPK pathways, and they play a distinct role in this process. Thus, the JNK and p38 MAPK pathway co-operatively mediate MMP-13 mRNA expression in rat HSCs.