Environmental Enrichment Modified Epigenetic Mechanisms in SAMP8 Mouse Hippocampus by Reducing Oxidative Stress and Inflammaging and Achieving Neuroprotection
FRONTIERS IN AGING NEUROSCIENCE
Authors: Grinan-Ferre, Christian; Puigoriol-Illamola, Dolors; Palomera-Avalos, Veronica; Perez-Caceres, David; Companys-Alemany, Julia; Camins, Antonio; Ortuno-Sahagun, Daniel; Teresa Rodrigo, M.; Pallas, Merce
Abstract
With the increase in life expectancy, aging and age-related cognitive impairments are becoming one of the most important issues for human health. At the same time, it has been shown that epigenetic mechanisms are emerging as universally important factors in life expectancy. The Senescence Accelerated Mouse P8 (SAMP8) strain exhibits age-related deterioration evidenced in learning and memory abilities and is a useful model of neurodegenerative disease. In SAMP8, Environmental Enrichment (EE) increased DNA-methylation levels (5-mC) and reduced hydroxymethylation levels (5-hmC),as well as increased histone H3 and H4 acetylation levels. Likewise, we found changes in the hippocampal gene expression of some chromatin-modifying enzyme genes, such as Dnmt3b. Hdac1. Hdac2. Sirt2, and Sirt6. Subsequently, we assessed the effects of EE on neuroprotection-related transcription factors, such as the Nuclear regulatory factor 2 (Nrf2)Antioxidant Response Element pathway and Nuclear Factor kappa Beta (NF-kappa B), which play critical roles in inflammation. We found that EE produces an increased expression of antioxidant genes, such as Hmox1. Aox1, and Cox2, and reduced the expression of inflammatory genes such as IL-6 and Cxcl10, all of this within the epigenetic context modified by EE. In conclusion, EE prevents epigenetic changes that promote or drive oxidative stress and inflammaging.
Lens ER-stress response during cataract development in Mip-mutant mice
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE
Authors: Zhou, Yuefang; Bennett, Thomas M.; Shiels, Alan
Abstract
Major intrinsic protein (MIP) is a functional water-channel (AQPO) that also plays a key role in establishing lens fiber cell architecture. Genetic variants of MIP have been associated with inherited and age-related forms of cataract; however, the underlying pathogenic mechanisms are unclear. Here we have used lens transcriptome profiling by microarray-hybridization and OCR to identify pathogenic changes during cataract development in Mip-mutant (Lop/ +) mice. In postnatal Lop/ + lenses (P7) 99 genes were up-regulated and 75 were down-regulated (>2-fold, p = <0.05) when compared with wild-type. A pathway analysis of up-regulated genes in the Lop/ + lens (P7) was consistent with endoplasmic reticulum (ER)-stress and activation of the unfolded protein response (UPR). The most up-regulated UPR genes (>4-fold) in the Lop/ + lens included Chacl > Ddit3 > Atf3 > Trib3 > Xbpl and the most down-regulated genes (>5-fold) included two anti-oxidant genes, Hspb1 and Hmox1. Lop/ + lenses were further characterized by abundant TUNEL-positive nuclei within central degenerating fiber cells, glutathione depletion, free-radical overproduction, and calpain hyper-activation. These data suggest that Lop/+ lenses undergo proteotoxic ER -stress induced cell-death resulting from prolonged activation of the Eif2ak3/Perk-Atf4-Ddit3-Chac1 branch of the UPR coupled with severe oxidative-stress. (C) 2016 The Authors. Published by Elsevier B.V.