Proteomic Analysis of Mouse Hypothalamus under Simulated Microgravity

Abstract

Exposure to altered microgravity during space travel induces changes in the brain and these are reflected in many of the physical behavior seen in the astronauts. The vulnerability of the brain to microgravity stress has been reviewed and reported. Identifying microgravity-induced changes in the brain proteome may aid in understanding the impact of the microgravity environment on brain function. In our previous study we have reported changes in specific proteins under simulated microgravity in the hippocampus using proteomics approach. In the present study the profiling of the hypothalamus region in the brain was studied as a step towards exploring the effect of microgravity in this region of the brain. Hypothalamus is the critical region in the brain that strictly controls the pituitary gland that in turn is responsible for the secretion of important hormones. Here we report a 2-dimensional gel electrophoretic analysis of the mouse hypothalamus in response to simulated microgravity. Lowered glutathione and differences in abundance expression of seven proteins were detected in the hypothalamus of mice exposed to microgravity. These changes included decreased superoxide dismutase-2 (SOD-2) and increased malate dehydrogenase and peroxiredoxin-6, reflecting reduction of the antioxidant system in the hypothalamus. Taken together the results reported here indicate that oxidative imbalance occurred in the hypothalamus in response to simulated microgravity.

Protective Effects of Flavonoids Against Oxidative Stress Induced by Simulated Microgravity in SH-SY5Y Cells

“…Data are expressed as mean ± SEM (n = 8). * P \ 0.05, ** P \ 0.01 compared with the static control group Neurochem Res (2010) 35:1445-1454 1451 shows that the nervous system is especially vulnerable to oxidative stress during microgravity conditions [5][6][7][8]. With continuing advancements in aerospace technology and more prolonged space flights, two things will become increasingly important in order to ensure the safety of prolonged space travel: an increased understanding-at both the organismal and cellular levels-of the effects of microgravity on the nervous system, and the taking of some effective measurements to achieve this.…”

“…Lipid peroxidation products (malondialdehyde, MDA) are increased in rats that are tail-suspended for 2 or 3 weeks to simulate microgravity [5,6]. A previous study detected lowered glutathione, decreased superoxide dismutase 2 (SOD2), and increased malate dehydrogenase and peroxiredoxin-6 in the hypothalamus of mice exposed to SMG, reflecting a reduction of antioxidant system function [7]. In another study, ROS are increased-with a concomitant decrease in glutathione-in brain stem and frontal cortex of mice exposed for 7 days to SMG [8].…”

Effect of microgravity on gene expression in mouse brain

“…More recently, a proteomic analysis of hippocampus of HU mice revealed changes in structural proteins coupled with the loss of proteins involved in cell metabolism (Sarkar et al 2006). Furthermore, a similar analysis performed in hypothalamus revealed alteration of biomarkers of oxidative stress indicating vulnerability of the hypothalamus to the stress generated by microgravity (Sarkar et al 2008). …”

Simulated microgravity affects semicarbazide-sensitive amine oxidase expression in recombinant Escherichia coli by HPLC-ESI-QQQ analysis

“…Previous cDNA microarray experiments showed that ten genes in human T lymphocytes were upregulated and 79 downregulated under simulated microgravity (Lewis et al 2001). Besides, GST and superoxide dismutase-2 decreased in the mouse hypothalamus under simulated microgravity through two-dimensional gel and matrix-assisted laser desorption ionization time of flight analysis (Sarkar et al 2008).The results obtained here indicate that microgravity cannot always elevate the amount of the recombinant protein expression under any circumstance, which was at least related with the target protein and temperature. However, the underlying mechanism still needs to be further investigated in the future study.…”