Nuclear factor kappa-B mediates selective induction of neuronal nitric oxide synthase in astrocytes during low-level inflammatory stimulation with MPTP

Abstract

Recent advances in understanding the progression of Parkinson's disease (PD) implicate perturbations in astrocyte function and induction of constitutively expressed neuronal nitric oxide synthase (NOS1) in both human PD and in the MPTP model of the disease. Transcriptional regulation of NOS1 is complex but recent data suggest that nuclear factor kappa B (NF-κB) is an important transcription factor involved in inducible expression of the gene. The data presented here demonstrate that mild activation of primary astrocytes with low or 'sub-optimal' concentrations of MPTP (1 µM) and the inflammatory cytokines tumor necrosis factor alpha (10 pg/ml) and interferon gamma (1 ng/ ml) results in selective induction of Nos1 mRNA and protein, increased production of nitric oxide (NO), and a significant elevation in global protein nitration. This mild inflammatory stimulus also resulted in activation and recruitment of p65 to a putative NF-κB response element located in the Nos1 promoter region flanking exon 1. A role for NF-κB in MPTP-dependent induction of NOS1 was confirmed through overexpression of a mutant IκBα super repressor of NF-κB that prevented induction of NOS1. The data presented here thus demonstrate a role for NF-κB in selective induction of NOS1 during early inflammatory activation of astrocytes stimulated by low-dose MPTP and inflammatory cytokines.

Nitric oxide synthase 1 and cyclooxygenase-2 enzymes are targets of muscarinic activation in normal and inflamed NIH3T3 cells

“…Consistent with this role, incorrect regulation of NF-jB has been linked to cancer or autoimmune diseases, septic shock, viral infection, and improper immune development. Our results indicate that NOS1 induction in NIH3T3* cells is dependent on NF-jB activation as it was previously reported in astrocytes [27]. Although various IjB proteins have been described, IjB-a and IjB-b are the most extensively studied.…”

“…By Western blot we confirmed the presence of NOS1 enzyme in NIH3T3 cells and the induction of this protein in LPS plus IFNc treated cells. Carbone et al [27] have recently demonstrated that NOS1 expression and NO production in astrocytes are upregulated under low level inflammatory stimulation in both human Parkinson 0 s disease and in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of the disease. In addition we confirmed that NOS1 upregulation induced by CARB is mediated by NF-jB activation either in untreated or in treated cells, since it was reversed by the proteosome inhibitor MG-132.…”

Receptor for advanced glycation endproducts (RAGE) deficiency protects against MPTP toxicity

“…S100B could be one of the factors involved in NF-κB activation, as it can activate p65/c-Rel transcription in a RAGE dependent manner (Kogel et al, 2004). Moreover, NF-κB mediates neuronal nitric oxide synthase (nNOS) induction in a cellular model of MPTP-toxicity (Carbone et al, 2008). Furthermore, inhibition of NF-κB with 1,1-bis(3′-indolyl)-1-( p-t -butylphenyl)methane resulted in a reduction of caspase activity and nNOS activation (Carbone et al, 2009).…”

Increased neuronal nitric oxide synthase dimerisation is involved in rat and human pancreatic beta cell hyperactivity in obesity

“…However, owing to a drastic increase in nNOS protein level, the overall enzyme activity appeared drastically reduced. nNOS overexpression could be due to an enhanced activity of transcription factors, as nuclear factor kappa-B (NFκB) and cAMP response element (CRE) are reportedly involved in nNOS induction [24][25][26]. In addition, the dimeric conformation of nNOS has been shown to protect the protein from proteolysis by the ubiquitinproteasome pathway [27].…”