CONTEXT: Depression is a major public health problem. Despite many years of research, the molecular mechanisms associated with depression remain unclear. Rap-1, activated in response to many extracellular stimuli, is one of the major substrates of protein kinase A, which participates in myriad physiologic functions in the brain, including cell survival and synaptic plasticity. Rap-1 is also activated directly by cyclic adenosine monophosphate through Epac, and thus participates in mediating physiologic functions independent of protein kinase A. OBJECTIVE: To examine whether the pathogenesis of depression is associated with altered activation and expression of Rap-1, as well as expression of Epac, in depressed suicide victims. DESIGN: Postmortem study. SETTING: Tissues were obtained from the Lenhossek Human Brain Program, Semmelweis University, Budapest, Hungary, and the Brain Collection Program of the Maryland Psychiatric Research Center, Baltimore. PARTICIPANTS: Postmortem brains of 28 depressed suicide victims and 28 nonpsychiatric control subjects. INTERVENTION: Examination of brain tissues. MAIN OUTCOME MEASURES: Rap-1 activation as well as messenger RNA and protein levels of Rap-1 and Epac in prefrontal cortex, hippocampus, and cerebellum. RESULTS: Rap-1 activation was significantly reduced (P<.001) in prefrontal cortex and hippocampus in the suicide group. This was associated with significant reductions in Rap-1 messenger RNA and protein levels (P<.001). In contrast, protein level of only Epac-2 (P<.001) but not Epac-1 (P = .89) was significantly increased in prefrontal cortex and hippocampus of these subjects. These changes were present whether the 2 cohorts were analyzed together or separately. None of the measures showed any significant change in cerebellum in the suicide group. CONCLUSION: Given the importance of Rap-1 in neuroprotection and synaptic plasticity, our findings of differential regulation of Rap-1 and Epac between brain regions suggest the relevance of these molecules in the pathophysiology of depression.
CONTEXT: Depression is a major public health problem. Despite many years of research, the molecular mechanisms associated with depression remain unclear. Rap-1, activated in response to many extracellular stimuli, is one of the major substrates of protein kinase A, which participates in myriad physiologic functions in the brain, including cell survival and synaptic plasticity. Rap-1 is also activated directly by cyclic adenosine monophosphate through Epac, and thus participates in mediating physiologic functions independent of protein kinase A. OBJECTIVE: To examine whether the pathogenesis of depression is associated with altered activation and expression of Rap-1, as well as expression of Epac, in depressed suicide victims. DESIGN: Postmortem study. SETTING: Tissues were obtained from the Lenhossek Human Brain Program, Semmelweis University, Budapest, Hungary, and the Brain Collection Program of the Maryland Psychiatric Research Center, Baltimore. PARTICIPANTS: Postmortem brains of 28 depressed suicide victims and 28 nonpsychiatric control subjects. INTERVENTION: Examination of brain tissues. MAIN OUTCOME MEASURES: Rap-1 activation as well as messenger RNA and protein levels of Rap-1 and Epac in prefrontal cortex, hippocampus, and cerebellum. RESULTS:Rap-1 activation was significantly reduced (P<.001) in prefrontal cortex and hippocampus in the suicide group. This was associated with significant reductions in Rap-1 messenger RNA and protein levels (P<.001). In contrast, protein level of only Epac-2 (P<.001) but not Epac-1 (P = .89) was significantly increased in prefrontal cortex and hippocampus of these subjects. These changes were present whether the 2 cohorts were analyzed together or separately. None of the measures showed any significant change in cerebellum in the suicide group. CONCLUSION: Given the importance of Rap-1 in neuroprotection and synaptic plasticity, our findings of differential regulation of Rap-1 and Epac between brain regions suggest the relevance of these molecules in the pathophysiology of depression.
Authors: Wolfgang H Sommer; Jessica Lidström; Hui Sun; Derek Passer; Robert Eskay; Stephen C J Parker; Stephanie H Witt; Ulrich S Zimmermann; Vanessa Nieratschker; Marcella Rietschel; Elliott H Margulies; Miklós Palkovits; Manfred Laucht; Markus Heilig Journal: Hum Mutat Date: 2010-08 Impact factor: 4.878
Authors: Shakevia Johnson; Craig A Stockmeier; Jeffrey H Meyer; Mark C Austin; Paul R Albert; Junming Wang; Warren L May; Grazyna Rajkowska; James C Overholser; George Jurjus; Lesa Dieter; Chandra Johnson; Donald B Sittman; Xiao-Ming Ou Journal: Neuropsychopharmacology Date: 2011-06-08 Impact factor: 7.853
Authors: Richard L Hauger; Victoria Risbrough; Robert H Oakley; J Alberto Olivares-Reyes; Frank M Dautzenberg Journal: Ann N Y Acad Sci Date: 2009-10 Impact factor: 5.691
Authors: Andrei I Molosh; Tammy J Sajdyk; William A Truitt; Weiguo Zhu; Gerry S Oxford; Anantha Shekhar Journal: Neuropsychopharmacology Date: 2013-01-28 Impact factor: 7.853