Nicotine coregulates multiple pathways involved in protein modification/degradation in rat brain

Abstract

Previously, we used cDNA microarrays to demonstrate that the phosphatidylinositol and MAP kinase signaling pathways are regulated by nicotine in different rat brain regions. In the present report, we show that, after exposure to nicotine for 14 days, ubiquitin, ubiquitinconjugating enzymes, 20S and 19S proteasomal subunits, and chaperonin-containing TCP-1 protein (CCT) complex members are upregulated in rat prefrontal cortex (PFC) while being downregulated in the medial basal hypothalamus (MBH). In particular, relative to saline controls, ubiquitins B and C were upregulated by 33% and 47% ( Pb0.01), respectively, in the PFC. The proteasome beta subunit 1 (PSMB1) and 26S ATPase 3 (PSMC3) genes were upregulated in the PFC by 95% and 119% ( Pb0.001), respectively. In addition to the protein degradation pathway of the ubiquitin-proteasome complexes, we observed in the PFC an increase in the expression of small, ubiquitin-related modifiers (SUMO) 1 and 2 by 80% and 33%, respectively ( Pb0.001), and in 3 of 6 CCT subunits by up to 150% ( Pb0.0001). To a lesser extent, a change in the opposite direction was obtained in the expression of the same gene families in the MBH. Quantitative real-time RT-PCR was used to validate the microarray results obtained with some representative genes involved in these pathways. Taken together, our results suggest that, in response to systemic nicotine administration, the ubiquitin-proteasome, SUMO, and chaperonin complexes provide an intricate control mechanism to maintain cellular homeostasis, possibly by regulating the composition and signaling of target neurons in a region-specific manner. D

Gene regulation of α4β2 nicotinic receptors: microarray analysis of nicotine‐induced receptor up‐regulation and anti‐inflammatory effects

“…Dunckley and Lukas found that nicotine exposure alters the expression of contactin 1, UBE2C, UBE2S, and Perkin in SH-SY5Y cells Lukas 2003, 2006) with a heavy emphasis on the ubiquitin proteosomal degradation pathway. Kane et al (2004) also reported changes in the proteosomaldegradation pathway using microarray analysis of nicotinetreated rat brain, but the contributing receptor subtypes in this study are not clear.…”

Nicotine response genetics in the zebrafish

“…In addition, altered protein kinetics has been proposed as one method of altering nicotinic receptor function as observed in recent nicotinic response work in cultured neurons (35). Evidence for a conserved role of mammalian cct8 in the nicotine response (36) includes strong expression in mouse neural tissue (37). In addition, rat cct8 mRNA is upregulated in the prefrontal cortex after exposure to nicotine (38).…”

Zebrafish for the Study of the Biological Effects of Nicotine

“…Behavioral assays have been developed in a number of animal models to measure many of the known physiological manifestations associated with drug addiction, including locomotor sensitization (Benwell & Balfour, 1992;Kalivas & Stewart, 1991), conditioned place preference (CPP; Tzschentke, 1998), self-administration (Stairs, Neugebauer, & Bardo, 2010), and withdrawal (André, Gulick, Portugal, & Gould, 2008). Behavioral assays define changes induced by drug exposure and enable differential molecular analysis of the resulting transcriptional (i.e., gene expression) and epigenetic states (Kane, Konu, Ma, & Li, 2004;Kumar et al, 2005;Levine et al, 2005;Nestler, 2008;Renthal et al, 2007;Romieu et al, 2008;Shen et al, 2008). As the reinforcing properties of addictive drugs are highly conserved, behavioral assays have been adapted to zebrafish to study addiction to cocaine (Darland & Dowling, 2001), ethanol (Lockwood, Bjerke, Kobayashi, & Guo, 2004;Peng et al, 2009), amphetamines (Ninkovic & Bally-Cuif, 2006;Webb et al, 2009), and opiates (Bretaud et al, 2007;Lau, Bretaud, Huang, Lin, & Guo, 2006;Sanchez-Simon & Rodriguez, 2008).…”