Involvement of cytosolic phospholipase A2 alpha signalling pathway in spontaneous and transforming growth factor-beta-induced activation of rat hepatic stellate cells

PLA2G12A as a Novel Biomarker for Colorectal Cancer with Prognostic Relevance

Metastasis is the leading cause of colorectal cancer (CRC)-related deaths. Therefore, the identification of accurate biomarkers predictive of metastasis is needed to better stratify high-risk patients to provide preferred management and reduce mortality. In this study, we identified 13 new genes that modified circulating tumor cell numbers using a genome-wide genetic screen in a whole animal CRC model. Candidate genes were subsequently evaluated at the gene expression level in both an internal human CRC cohort of 153 patients and an independent cohort from the TCGA including 592 patients. Interestingly, the expression of one candidate, PLA2G12A, significantly correlated with both the time to recurrence and overall survival in our CRC cohort, with its low expression being an indicator of a poor clinical outcome. By examining the TCGA cohort, we also found that low expression of PLA2G12A was significantly enriched in epithelial-mesenchymal transition signatures. Finally, the candidate functionality was validated in vitro using three different colon cancer cell lines, revealing that PLA2G12A deficiency increases cell proliferation, migration, and invasion. Overall, our study identifies PLA2G12A as a prognostic biomarker of early-stage CRC, providing evidence that its deficiency promotes tumor growth and dissemination.

Roles of nuclear receptors in hepatic stellate cells

Introduction: Hepatic stellate cells (HSCs) are essential for physiological homeostasis of the liver extracellular matrix (ECM). Excessive transdifferentiation of HSC from a quiescent to an activated phenotype contributes to disrupt this balance and can lead to liver fibrosis. Accumulating evidence has suggested that nuclear receptors (NRs) are involved in the regulation of HSC activation, proliferation, and function. Therefore, these NRs may be therapeutic targets to balance ECM homeostasis and inhibit HSC activation in liver fibrosis.Areas covered: In this review, the authors summarized the recent progress in the understanding of the regulatory role of NRs in HSCs and their potential as drug targets in liver fibrosis.Expert opinion: NRs are still potential therapy targets for inhibiting HSCs activation and liver fibrosis. However, the development of NRs agonists or antagonists to inhibit HSCs requires fully consideration of systemic effects.

Daily Aspirin Use Associated With Reduced Risk For Fibrosis Progression In Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

There are few data from prospective studies on the effects of aspirin on fibrosis in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

We performed a prospective cohort study of 361 adults with biopsy-confirmed NAFLD, from 2006 through 2015, examined every 3-12 months for incident advanced fibrosis defined using serial measurements of validated indices (the Fibrosis-4, NAFLD fibrosis score, and aspartate aminotransferase to platelet ratio indices). Histologic analyses of liver biopsies collected at baseline were performed by a blinded pathologist. Information collected at baseline and at each examination included frequency and duration of aspirin and nonsteroidal anti-inflammatory drug (NSAID) use. Using multivariable-adjusted logistic regression, we estimated the association of aspirin use with prevalent steatohepatitis (NASH) and fibrosis. Using multivariable-adjusted Cox proportional hazards modeling, we estimated the association between aspirin use and risk for fibrosis progression.

RESULTS

At enrollment, 151 subjects used aspirin daily. Compared with non-regular use, daily aspirin use was associated with significantly lower odds of NASH (adjusted odds ratio, 0.68; 95% CI, 0.37-0.89) and fibrosis (adjusted odds ratio, 0.54; 95% CI, 0.31-0.82). Among individuals with baseline F0-F2 fibrosis (n = 317), 86 developed advanced fibrosis over 3692 person-years. Daily aspirin users had significantly lower risk for developing incident advanced fibrosis vs non-regular users (adjusted hazard ratio [aHR], 0.63; 95% CI, 0.43-0.85). This relationship appeared to be duration dependent (adjusted P trend=.026), with the greatest benefit found with at least 4 years or more of aspirin use (aHR, 0.50; 95% CI, 0.35-0.73). Conversely, use of nonaspirin NSAIDs was not associated with risk for advanced fibrosis (aHR, 0.93; 95% CI, 0.81-1.05).

CONCLUSIONS

In a prospective study of patients with biopsy-proven NAFLD, daily aspirin use was associated with less severe histologic features of NAFLD and NASH, and lower risk for progression to advanced fibrosis with time.

Peroxisome proliferator-activated receptor (PPAR)β/δ, a possible nexus of PPARα- and PPARγ-dependent molecular pathways in neurodegenerative diseases: Review and novel hypotheses

Peroxisome proliferator-activated receptors (PPARα, -β/δ and -γ) are lipid-activated transcription factors. Synthetic PPARα and PPARγ ligands have neuroprotective properties. Recently, PPARβ/δ activation emerged as the focus of a novel approach for the treatment of a wide range of neurodegenerative diseases. To fill the gap of knowledge about the role of PPARβ/δ in brain, new hypotheses about PPARβ/δ involvement in neuropathological processes are requested. In this paper, we describe a novel hypothesis, claiming the existence of tight interactions between the three PPAR isotypes, which we designate the "PPAR triad". We propose that PPARβ/δ has a central control of the PPAR triad. The majority of studies analyze the regulation only by one of the PPAR isotypes. A few reports describe the mutual regulation of expression levels of all three PPAR isotypes by PPAR agonists. Analysis of these studies where pairwise interactions of PPARs were described allows us to support the existence of the PPAR triad with central role for PPARβ/δ. In the present review, we propose the hypothesis that in a wide range of brain disorders, PPARβ/δ plays a central role between PPARα and PPARγ. Finally, we prove the advantages of the PPAR triad concept by describing hypotheses of PPARβ/δ involvement in the regulation of myelination, glutamate-induced neurotoxicity, and signaling pathways of reactive oxygen species/NO/Ca(2+).

Effect of ALA treatment on cell proliferation, secretion of types Ⅰ and Ⅲ collagen, and α-SMA expression in rat hepatic satellite cells treated with transforming growth factor β1

AIM: To investigate the effect of treatment with α-linolenic acid (ALA) on cell proliferation, secretion of types Ⅰ and Ⅲ collagen, and α-smooth muscle actin (α-SMA) expression in transforming growth factor beta 1 (TGF-β1)-treated rat hepatic satellite cells (HSCs).

METHODS: Cultured HSCs were divided into five groups: control group, TGF-β1 group (5 ng/mL) and three TGF-β1 plus LNA groups (treated with TGF-β1 plus 50, 150 or 250 ng/mL of ALA). Cell proliferation was assessed by MTT assay. The levels of types Ⅰ and Ⅲ collagen were measured by ELISA. Western blot was used to detect the expression of α-smooth muscle actin.

RESULTS: TGF-β1 induced cell proliferation and increased the secretion of collagen in HSCs. Compared to the TGF-β1 group, treatment with different doses of ALA inhibited cell proliferation and decreased the secretion of types Ⅰ and Ⅲ collagen and expression of α-SMA (all P < 0.05).

CONCLUSION: Treatment with ALA inhibits TGF-β1-induced cell proliferation, secretion of types Ⅰ and Ⅲ collagen, and α-SMA expression in rat HSCs.

Capsaicin induces de-differentiation of activated hepatic stellate cell

Hepatic stellate cells (HSC) play a key role in liver fibrogenesis. Activation of PPARγ and inhibition of fibrogenic molecules are potential strategies to block HSC activation and differentiation. A number of natural products have been suggested to have antifibrotic effects for the de-activation and de-differentiation of HSCs. The purpose of this study was to investigate the in vitro effects of capsaicin on HSC de-activation and de-differentiation. The results demonstrated that capsaicin induced quiescent phenotype in GRX via PPARγ activation. Significant decrease in COX-2 and type I collagen mRNA expression was observed in the first 24 h of treatment. These events preceded the reduction of TGF-β1 and total collagen secretion. Thus, capsaicin promoted down-regulation of HSC activation by its antifibrotic and anti-inflammatory actions. These findings demonstrate that capsaicin may have potential as a novel therapeutic agent for the treatment of liver fibrosis.