Xenobiotic metabolism and its physiological consequences in high-Antarctic Notothenioid fishes

The Antarctic ecosystem is progressively exposed to anthropogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs). So far, it is largely unknown if PAHs leave a mark in the physiology of high-Antarctic fish. We approached this issue via two avenues: first, we examined the functional response of the aryl hydrocarbon receptor (Ahr), which is a molecular initiating event of many toxic effects of PAHs in biota. Chionodraco hamatus and Trematomus loennbergii served as representatives for high-Antarctic Notothenioids, and Atlantic cod, Gadus morhua as non-polar reference species. We sequenced and cloned the Ahr ligand binding domain (LBD) of the Notothenioids and deployed a GAL4-based luciferase reporter gene assay expressing the Ahr LBD. Benzo[a]pyrene (BaP), beta-naphthoflavone and chrysene were used as ligands for the reporter gene assay. Second, we investigated the energetic costs of Ahr activation in isolated liver cells of the Notothenioids during acute, non-cytotoxic BaP exposure. In the reporter assay, the Ahr LBD of Atlantic cod and the Antarctic Notothenioids were activated by the ligands tested herein. In the in vitro assays with isolated liver cells of high-Antarctic Notothenioids, BaP exposure had no effect on overall respiration, but caused shifts in the respiration dedicated to protein synthesis. Thus, our study demonstrated that high-Antarctic fish possess a functional Ahr that can be ligand-activated in a concentration-dependent manner by environmental contaminants. This is associated with altered cost for cellular protein synthesis. Future studies have to show if the toxicant-induced activation of the Ahr pathway may lead to altered organism performance of Antarctic fish.

A new, economical, and easy protocol to culture 3D mouse hepatoid and cholangoid

Despite the high efficiency of self-regeneration in liver, liver stem cell organoid culture is way behind other cell types such as intestinal organoid (Enteroid). The contributing factor is the lack of effi¬cient technique to isolate liver cells and to culture liver stem cell organoid. Here we reported a new, eco¬nomical, and simple method to generate 3D hepatocyte organoid (Hepatoid) and cholangiocyte organoid (Cholangoid). We have isolated liver cells using ice-cold 3mM EDTA PBS medium. The isolated cells were cultured on 50% Conditional Medium. After 1 or 4 days post isolation and culture, Cholangoid and Hepatoid were readily to be detected under light microscope and they continued to grow well after several passages. This method could be used to isolate and culture human liver organoids. This feasible protocol will greatly facilitate more research on liver function and diseases using liver cell organoids. Keywords: Organoid; Stem cell; 3D culture; Liver

STUDY ON ANTIOXIDANT ACTIVITIES OF THE AERIAL PARTS AND SOME COMPOUNDS ISOLATED FROM Archidendron clypearia ((Jack) I. Niels Part 2. ISOLATING, DETERMINING STRUCTURE AND ANTIOXIDANT CAPABILITY OF SOME COMPOUNDS FROM ETHYL ACETATE EXTRACT

The antioxidant activity in vitro of methanol extract of Archidendron clypearia was evaluated by in vitro tests on isolated liver cells of mouses with ED50 value ​​ of 2.18 μg/mL compared to that of curcumin of 1.87 µg/mL. Using combined chromatographic methods, four compounds were isolated from chloroform extract of the Archidendron clypearia. Their structures were elucidated to be daucosterol, 1-octacosanol, docosenoic acid, and methyl gallate by 1D- and 2D-NMR spectroscopic methods and in comparison with those reported in the literature. This is the first report of these compounds from the plant. All four compounds showed quite high antioxidant activity, for which methyl gallate was the highest one.

Portal hypertensive response to kinin

Portal hypertension is the most common complication of chronic liver diseases, such as cirrhosis. The increased intrahepatic vascular resistance seen in hepatic disease is due to changes in cellular architecture and active contraction of stellate cells. In this article, we review the historical aspects of the kallikrein-kinin system, the role of bradykinin in the development of disease, and our main findings regarding the role of this nonapeptide in normal and experimentalmodels of hepatic injury using the isolated rat liver perfusion model (mono and bivascular) and isolated liver cells. We demonstrated that: 1) the increase in intrahepatic vascular resistance induced by bradykinin is mediated by B2 receptors, involving sinusoidal endothelial and stellate cells, and is preserved in the presence of inflammation, fibrosis, and cirrhosis; 2) the hepatic arterial hypertensive response to bradykinin is calcium-independent and mediated by eicosanoids; 3) bradykinin does not have vasodilating effect on the pre-constricted perfused rat liver; and, 4) after exertion of its hypertensive effect, bradykinin is degraded by angiotensin converting enzyme. In conclusion, the hypertensive response to BK is mediated by the B2 receptor in normal and pathological situations. The B1 receptor is expressed more strongly in regenerating and cirrhotic livers, and its role is currently under investigation.