Luteolin-7-diglucuronide attenuates isoproterenol-induced myocardial injury and fibrosis in mice
ACTA PHARMACOLOGICA SINICA
Authors: Ning, Bing-Bing; Zhang, Yong; Wu, Dan-Dan; Cui, Jin-Gang; Liu, Li; Wang, Pei-Wei; Wang, Wen-Jian; Zhu, Wei-Liang; Chen, Yu; Zhang, Teng
Abstract
Myocardial injury and ensuing fibrotic alterations impair normal heart architecture and cause cardiac dysfunction. Oxidative stress has been recognized as a key player in the pathogenesis of cardiac injury and progression of cardiac dysfunction, and promoting fibrosis. In the current study we investigated whether luteolin-7-diglucuronide (L7DG), a naturally occurring antioxidant found in edible plants, could attenuate isoproterenol (ISO)-induced myocardial injury and fibrosis in mice and the underlying mechanisms. Myocardial injury and fibrosis were induced in mice via injection of ISO (5 mg . kg(-1) u d(-1), ip) for 5 or 10 d. Two treatment regimens (pretreatment and posttreatment) were employed to administer L7DG (5-40 mg . kg(-1) . d(-1), ip) into the mice. After the mice were euthanized, morphological examinations of heart sections revealed that both L7DG pretreatment and posttreatment regimens significantly attenuated ISOinduced myocardial injury and fibrosis. But the pretreatment regimen caused better protection against ISO-induced myocardial fibrosis than the posttreatment regimen. Furthermore, L7DG pretreatment blocked ISO-stimulated expression of the genes (Cyba, Cybb, Ncf1, Ncf4 and Rac2) encoding the enzymatic subunits of NADPH oxidase, which was the primary source of oxidant production in mammalian cells. Moreover, L7DG pretreatment significantly suppressed ISO-stimulated expression of collagen genes Col1a1, Col1a2, Col3a1, and Col12a1 and non-collagen extracellular matrix genes fibrillin-1, elastin, collagen triple helix repeat containing 1 and connective tissue growth factor. In addition, L7DG pretreatment almost reversed ISO-altered expression of microRNAs that were crosstalking with TGF beta-mediated fibrosis, including miR-29c-3p, miR-29c-5p, miR-30c-3p, miR-30c-5p and miR-21. The current study demonstrated for the first time that L7DG is pharmacologically effective in protecting the heart against developing ISO-induced injury and fibrosis, justifying further evaluation of L7DG as a cardioprotective agent to treat related cardiovascular diseases.
A Genome-Wide Screen in Mice To Identify Cell-Extrinsic Regulators of Pulmonary Metastatic Colonisation
G3-GENES GENOMES GENETICS
Authors: van der Weyden, Louise; Swiatkowska, Agnieszka; Iyer, Vivek; Speak, Anneliese O.; Adams, David J.
Abstract
Metastatic colonization, whereby a disseminated tumor cell is able to survive and proliferate at a secondary site, involves both tumor cell-intrinsic and -extrinsic factors. To identify tumor cell-extrinsic (microenvironmental) factors that regulate the ability of metastatic tumor cells to effectively colonize a tissue, we performed a genome-wide screen utilizing the experimental metastasis assay on mutant mice. Mutant and wildtype (control) mice were tail vein-dosed with murine metastatic melanoma B16-F10 cells and 10 days later the number of pulmonary metastatic colonies were counted. Of the 1,300 genes/genetic locations (1,344 alleles) assessed in the screen 34 genes were determined to significantly regulate pulmonary metastatic colonization (15 increased and 19 decreased; P < 0.005 and genotype effect +55). While several of these genes have known roles in immune system regulation (Bach2, Cyba, Cybb, Cybc1, Id2, Igh-6, Irf1, Irf7, Ncf1, Ncf2, Ncf4 and Pik3cg) most are involved in a disparate range of biological processes, ranging from ubiquitination (Herc1) to diphthamide synthesis (Dph6) to Rho GTPase-activation (Arhgap30 and Fgd4), with no previous reports of a role in the regulation of metastasis. Thus, we have identified numerous novel regulators of pulmonary metastatic colonization, which may represent potential therapeutic targets.