The neuroprotective and neurogenic effects of neuropeptide Y administration in an animal model of hippocampal neurodegeneration and temporal lobe epilepsy induced by trimethyltin
JOURNAL OF NEUROCHEMISTRY
Authors: Corvino, Valentina; Marchese, Elisa; Giannetti, Stefano; Lattanzi, Wanda; Bonvissuto, Davide; Biamonte, Filippo; Mongiovi, Adriana Maria; Michetti, Fabrizio; Geloso, Maria Concetta
Abstract
J. Neurochem. (2012) 122, 415426. Abstract The effects of intracerebroventricular administration of neuropeptide Y (NPY), which is believed to play an important role in neuroprotection against excitotoxicity and in the modulation of adult neurogenesis, were evaluated in an animal model of hippocampal neurodegeneration and temporal lobe epilepsy represented by trimethyltin (TMT) intoxication. A single TMT injection (8 mg/kg) causes, in the rat brain, massive neuronal death, selectively involving pyramidal neurons, accompanied by glial activation and enhanced hippocampal neurogenesis. Our data indicate that intracerebroventricular administration of exogenous NPY (at the dose of 2 mu g/2 mu L, 4 days after TMT-administration), in adult rats, exerts a protective role in regard to TMT-induced hippocampal damage and a proliferative effect on the hippocampal neurogenic niche through the up-regulation of Bcl-2, Bcl2l1, Bdnf, Sox-2, NeuroD1, Noggin and Doublecortin genes, contributing to delineate more clearly the role of NPY in in vivo neurodegenerative processes.
The IL-4/STAT6 signaling axis establishes a conserved microRNA signature in human and mouse macrophages regulating cell survival via miR-342-3p
GENOME MEDICINE
Authors: Czimmerer, Zsolt; Varga, Tamas; Kiss, Mate; Ovando Vazquez, Cesare; Quang Minh Doan-Xuan; Ruckerl, Dominik; Tattikota, Sudhir Gopal; Yan, Xin; Nagy, Zsuzsanna S.; Daniel, Bence; Poliska, Szilard; Horvath, Attila; Nagy, Gergely; Varallyay, Eva; Poy, Matthew N.; Allen, Judith E.; Bacso, Zsolt; Abreu-Goodger, Cei; Nagy, Laszlo
Abstract
Background: IL-4-driven alternative macrophage activation and proliferation are characteristic features of both antihelminthic immune responses and wound healing in contrast to classical macrophage activation, which primarily occurs during inflammatory responses. The signaling pathways defining the genome-wide microRNA expression profile as well as the cellular functions controlled by microRNAs during alternative macrophage activation are largely unknown. Hence, in the current work we examined the regulation and function of IL-4-regulated microRNAs in human and mouse alternative macrophage activation. Methods: We utilized microarray-based microRNA profiling to detect the dynamic expression changes during human monocyte-macrophage differentiation and IL-4-mediated alternative macrophage activation. The expression changes and upstream regulatory pathways of selected microRNAs were further investigated in human and mouse in vitro and in vivo models of alternative macrophage activation by integrating small RNA-seq, ChIP-seq, ChIP-quantitative PCR, and gene expression data. MicroRNA-controlled gene networks and corresponding functions were identified using a combination of transcriptomic, bioinformatic, and functional approaches. Results: The IL-4-controlled microRNA expression pattern was identified in models of human and mouse alternative macrophage activation. IL-4-dependent induction of miR-342-3p and repression of miR-99b along with miR-125a-5p occurred in both human and murine macrophages in vitro. In addition, a similar expression pattern was observed in peritoneal macrophages of Brugia malayi nematode-implanted mice in vivo. By using IL4Ra- and STAT6-deficient macrophages, we were able to show that IL-4-dependent regulation of miR-342-3p, miR-99b, and miR-125a-5p is mediated by the IL-4Ra-STAT6 signaling pathway. The combination of gene expression studies and chromatin immunoprecipitation experiments demonstrated that both miR-342-3p and its host gene, EVL, are coregulated directly by STAT6. Finally, we found that miR-342-3p is capable of controlling macrophage survival through targeting an anti-apoptotic gene network including Bcl2l1. Conclusions: Our findings identify a conserved IL-4/STAT6-regulated microRNA signature in alternatively activated human and mouse macrophages. Moreover, our study indicates that miR-342-3p likely plays a pro-apoptotic role in such cells, thereby providing a negative feedback arm to IL-4-dependent macrophage proliferation.