Obesity is the main risk factor for developing type II diabetes (T2D), a major and growing public health problem. Elevated adiposity leads to central leptin and insulin resistance, which in turn can trigger changes in homeostatic neural circuitry in the hypothalamus. This can ultimately lead to the development of metabolic syndrome and T2D. Neurogenesis in the adult hypothalamic parenchyma is disrupted by high fat diet (HFD) and leptin deficiency, leading to a reduction in the number of anorexigenic POMC- expressing neurons. We have recently identified hypothalamic tanycytes as a second source of newborn neurons in adult hypothalamus. Our preliminary data suggests that while HFD and leptin deficiency stimulate tanycyte-derived neurogenesis, tanycyte-derived neurons promote weight gain in wildtype animals but inhibit weight gain in leptin-deficient mice. The studies proposed here aim to improve our understanding of how tanycyte-derived neurons regulate body weight, and to determine how dietary signals regulate tanycyte-derived neurogenesis. First, using genetic approaches, we plan to investigate the physiological consequences of selectively disrupting and enhancing tanycyte-derived neurogenesis. Second, we plan to investigate the molecular mechanisms by which both HFD-induced cytokines such as CNTF and leptin regulate tanycyte-derived neurogenesis. Finally, we propose to determine the exact identity of tanycyte-derived neurons and to identify their post-synaptic targets. We anticipate that these studies will ultimately assist in the design of novel therapies for treatment of obesity and T2D.

Public Health Relevance

Management of obesity is critical for treating type II diabetes (T2D), but less than 15% of individuals achieve lasting weight loss through diet and exercise alone. We have found that tanycytes in the hypothalamus generate new neurons that regulate body weight. We propose to determine exactly how these newly formed neurons regulate body weight, and how dietary signals control the formation of new hypothalamic neurons, with the goal of developing new treatments for obesity and T2D.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK108230-04
Application #
9669023
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Hyde, James F
Project Start
2015-12-01
Project End
2019-11-30
Budget Start
2018-12-01
Budget End
2019-11-30
Support Year
4
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Neurosciences
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21205
Newman, Elizabeth A; Wu, Dan; Taketo, Makoto Mark et al. (2018) Canonical Wnt signaling regulates patterning, differentiation and nucleogenesis in mouse hypothalamus and prethalamus. Dev Biol 442:236-248
Newman, Elizabeth A; Kim, Dong Won; Wan, Jun et al. (2018) Foxd1 is required for terminal differentiation of anterior hypothalamic neuronal subtypes. Dev Biol 439:102-111
Yoo, Sooyeon; Blackshaw, Seth (2018) Regulation and function of neurogenesis in the adult mammalian hypothalamus. Prog Neurobiol 170:53-66
Bedont, Joseph L; LeGates, Tara A; Buhr, Ethan et al. (2017) An LHX1-Regulated Transcriptional Network Controls Sleep/Wake Coupling and Thermal Resistance of the Central Circadian Clockworks. Curr Biol 27:128-136
Bedont, Joseph L; Newman, Elizabeth A; Blackshaw, Seth (2015) Patterning, specification, and differentiation in the developing hypothalamus. Wiley Interdiscip Rev Dev Biol 4:445-68