The cellular mechanisms underlying neurogenesis, neurodevelopment and neuroregeneration are complex processes hat balance neuronal survival and proliferation with differentiation. These processes involve the spatial and temporal orchestration of a succession of neuroregulatory factors and the facility with which particular neurotrophic signals can adapt to diverse signaling pathways appears key to a successful neuronal developmental and regeneration program. Many neuropeptidergic systems are essential components of that process and among neuropeptide families, the vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase activating polypeptides (PACAP) have well establishec roles in neurotransmitter and neurotrophic signaling. In our studies of neuronal transmitter and bioactive peptide production, we identified the high potency and efficacy of PACAP peptides in stimulating superior cervical ganglior SCG) sympathetic neuron transmitter/peptide production and secretion, established the preferential high expressior of only the PACAP-selective PAC1(short)HOP1 receptor splice variant in SCG neurons and demonstrated the unique coupling of PAC1 (short)HOP1 receptor isoform to multiple intracellular signaling cascades. These studies have allowed us to structure studies to define the cellular mechanisms of PACAP/PAC1 receptor function; accordingly, we have hypothesized that the ability for the PAC1 receptor to activate multiple second messenger pathways underlies its functional diversity in regulating the many different facets of PACAP-mediated neurotransmitter and neurotrophic actions. Our work has already suggested novel mechanisms of PAC1 receptor Trp channel activation in PACAP mediated neurotransmissin; we will pursue these and complementary studies with the postulate that PAC1 receptor activation of specific MEK/ERK and P13K/AM trophic signaling pathways during precise developmental periods or altered physiological states, provides critical signals for neuronal proliferation, differentiation or regeneration.
Our aims are: 1) to establish the intracellular signaling mechanisms that transduce the PACAP/PAC1 receptor-mediated neurotrophic signals; 2) define the particular PAC1 receptor-mediated signaling pathway that engages each neurotrophic response; and 3) establish the roles of Tm channels in PACAP function. We feel these studies are unique not only in understanding PACAP/PAC1 receptor actions in physiological context, but also important ir providing essential insights to the diverse roles of G-protein coupled receptor signaling in neuronal function and development. These studies may suggest future strategies to facilitate neuronal regeneration to injury and disease.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD027468-13
Application #
6895488
Study Section
Special Emphasis Panel (ZRG1-MDCN-5 (01))
Program Officer
Henken, Deborah B
Project Start
2001-06-01
Project End
2007-05-31
Budget Start
2005-06-01
Budget End
2007-05-31
Support Year
13
Fiscal Year
2005
Total Cost
$306,788
Indirect Cost
Name
University of Vermont & St Agric College
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Ressler, Kerry J; Mercer, Kristina B; Bradley, Bekh et al. (2011) Post-traumatic stress disorder is associated with PACAP and the PAC1 receptor. Nature 470:492-7
May, Victor; Lutz, Eve; MacKenzie, Christopher et al. (2010) Pituitary adenylate cyclase-activating polypeptide (PACAP)/PAC1HOP1 receptor activation coordinates multiple neurotrophic signaling pathways: Akt activation through phosphatidylinositol 3-kinase gamma and vesicle endocytosis for neuronal survival. J Biol Chem 285:9749-61
Hammack, Sayamwong E; Roman, Carolyn W; Lezak, Kimberly R et al. (2010) Roles for pituitary adenylate cyclase-activating peptide (PACAP) expression and signaling in the bed nucleus of the stria terminalis (BNST) in mediating the behavioral consequences of chronic stress. J Mol Neurosci 42:327-40
Hammack, Sayamwong E; Cheung, Joseph; Rhodes, Kimberly M et al. (2009) Chronic stress increases pituitary adenylate cyclase-activating peptide (PACAP) and brain-derived neurotrophic factor (BDNF) mRNA expression in the bed nucleus of the stria terminalis (BNST): roles for PACAP in anxiety-like behavior. Psychoneuroendocrinology 34:833-43
Braas, Karen M; Schutz, Kristin C; Bond, Jeffrey P et al. (2007) Microarray analyses of pituitary adenylate cyclase activating polypeptide (PACAP)-regulated gene targets in sympathetic neurons. Peptides 28:1856-70
Pavelock, Kristen A; Girard, Beatrice M; Schutz, Kristin C et al. (2007) Bone morphogenetic protein down-regulation of neuronal pituitary adenylate cyclase-activating polypeptide and reciprocal effects on vasoactive intestinal peptide expression. J Neurochem 100:603-16
Girard, Beatrice A; Lelievre, Vincent; Braas, Karen M et al. (2006) Noncompensation in peptide/receptor gene expression and distinct behavioral phenotypes in VIP- and PACAP-deficient mice. J Neurochem 99:499-513
Girard, Beatrice M; Keller, Emily T; Schutz, Kristin C et al. (2004) Pituitary adenylate cyclase activating polypeptide and PAC1 receptor signaling increase Homer 1a expression in central and peripheral neurons. Regul Pept 123:107-16
Braas, K M; Rossignol, T M; Girard, B M et al. (2004) Pituitary adenylate cyclase activating polypeptide (PACAP) decreases neuronal somatostatin immunoreactivity in cultured guinea-pig parasympathetic cardiac ganglia. Neuroscience 126:335-46
Girard, Beatrice M; May, Victor; Bora, Susan H et al. (2002) Regulation of neurotrophic peptide expression in sympathetic neurons: quantitative analysis using radioimmunoassay and real-time quantitative polymerase chain reaction. Regul Pept 109:89-101

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