title: Specific progressive cAMP reduction implicates energy deficit in presymptomatic Huntington's disease knock-in mice.
abstract: Defects in gene transcription and mitochondrial function have been implicated in the dominant disease process that leads to the loss of striatal neurons in Huntington's disease (HD). Here we have used precise genetic HD mouse and striatal cell models to investigate the hypothesis that decreased cAMP responsive element (CRE)-mediated gene transcription may reflect impaired energy metabolism. We found that reduced CRE-signaling in Hdh(Q111) striatum, monitored by brain derived neurotrophic factor and phospho-CRE binding protein (CREB), predated inclusion formation. Furthermore, cAMP levels in Hdh(Q111) striatum declined from an early age (10 weeks), and cAMP was significantly decreased in HD postmortem brain and lymphoblastoid cells, attesting to a chronic deficit in man. Reduced CRE-signaling in cultured STHdh(Q111) striatal cells was associated with cytosolic CREB binding protein that mirrored diminished cAMP synthesis. Moreover, mutant cells exhibited mitochondrial respiratory chain impairment, evidenced by decreased ATP and ATP/ADP ratio, impaired MTT conversion and heightened sensitivity to 3-nitropropionic acid. Thus, our findings strongly suggest that impaired ATP synthesis and diminished cAMP levels amplify the early HD disease cascade by decreasing CRE-regulated gene transcription and altering energy dependent processes essential to neuronal cell survival.
authors.affiliation: Molecular Neurogenetics Unit, Massachusetts General Hospital, Building 149, 13th St, Charlestown, MA 02129, USA.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gines
authors.forename: Ihn Sik
authors.initials: IS
authors.lastname: Seong
authors.forename: Elisa
authors.initials: E
authors.lastname: Fossale
authors.forename: Elena
authors.initials: E
authors.lastname: Ivanova
authors.forename: Flavia
authors.initials: F
authors.lastname: Trettel
authors.forename: James F
authors.initials: JF
authors.lastname: Gusella
authors.forename: Vanessa C
authors.initials: VC
authors.lastname: Wheeler
authors.forename: Francesca
authors.initials: F
authors.lastname: Persichetti
authors.forename: Marcy E
authors.initials: ME
authors.lastname: MacDonald
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004195:Disease Models, Animal; D006816:Huntington Disease / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases