The role of neuronal Cdc-2-Like kinase 2 (Clk2) in the modulation of energy balance

• Grant number: 15/16561-7
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): January 01, 2016
• Effective date (End): December 31, 2016
• Field of knowledge: Biological Sciences - Biochemistry - Metabolism and Bioenergetics
• Principal Investigator: Patrícia de Oliveira Prada
• Grantee: Paula Gabriele Fernandes Quaresma Bergonsi
• Supervisor: Young-Bum Kim
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Research place: Harvard University, Boston, United States
• Associated to the scholarship: 12/10058-3 - STUDY OF CLK2 REGULATION IN HYPOTHALAMUS OF OBESE MICE, BP.DR

Abstract

The capacity to adjust food intake in response to changing energy requirements is essential for survival and the hypothalamus plays an important role in the regulation of whole-body energy balance by integrating nutrient and hormone signals from peripheral inputs. Insulin and leptin are hormones that though their intracellular signaling control food intake and energy expenditure stimulating anorexigenic inputs and repressing orexigenics inputs in the hypothalamus. ARC is consider the "first-order center" for regulating food intake. In the ARC, there are two most studied neuronal populations, the anorectic POMC/CART-expressing neurons that reduce food intake and increase energy expenditure; and the orexigenic AgRP/NPY-expressing neurons that stimulate food intake and reduction of energy expenditure. CLK2 is a protein regulated by refeeding and insulin in a PI3K/AKT manner in the liver, and its activation though 343 threonine phosphorylation leads to repression of hepatic glucose output. In our preliminary study, we observed that CLK2 is expressed in hypothalamus of contral mice and its regulated by refeeding, insulin and leptin in a PI3K/JAK2/AKT manner; and this regulation is blunted in DIO mice. We observed also, that CLK2 chronic inhibition in whole hypothalamus in lean mice led to obese phenotype, explained by decreasing energy expenditure and increasing food intake; and chronic overexpressing of CLK2 with adenovirus in DIO mice partially reversed the obese phenotype, it was explained by the increase of energy expenditure and the decrease of food intake. Thus, the preliminary results provided some evidences that hypothalamic CLK2 is important to control energy homeostasis and this effect exerted by hypothalamus through insulin and leptin signaling. In this sense our aims are: 1) to investigate whether CLK2 is expressed in NPY, AgRP and POMC neurons in ARC nucleus of the hypothalamus, by double labeling immunofluorescence; 2) to produce and inject the AAV-Cre expressing CLK2 or mutant CLK2 in genetically modified animals in which cell type-specific promoters drive expression of cre recombinase in specific populations of neurons (identified in the first aim). Then, investigate the phenotype of AAV-Cre expressing CLK2 or expressing mutant CLK2 in POMC or AgRP cre mice on chow or high fat diet. (AU)