Previously, we discovered that neuropeptide Y (NPY), its Y2Rs and an endothelial dipeptidyl peptidase IV form a potent angiogenic system. In addition to NPY's main secretory pool in sympathetic nerves activated by stress, other non-neuronal sources were identified in ECs and platelets, contributing to ischemic angiogenesis and atherosclerosis. As adipose tissue actively remodels, in the last period we studied NPY's role in fat angiogenesis and growth. This led to discovery of adipogenic actions of NPY and the phenomenon of "stress-induced obesity." Chronic stress augmented high fat diet-induced obesity and metabolic syndrome (MetSyn) by stimulating angiogenesis, inflammation and de-novo adipogenesis through up-regulated NPYY2R system, predominantly in the abdominal fat due to locally produced glucocorticoids. Stress/NPY-induced angio/adipogenesis and obesity were prevented by intra-fat Y2R inhibition or deletion;this work offered new avenues for fat remodeling and anti-obesity/MetSyn therapies. What characterizes "stressed fat", how lasting are its effects on fat tissue and metabolic consequences, and which NPY-Y2R carrying cells are responsible for it - is unknown and will now be studied. Stress appears to target neurovascular niches which contain nerves, adipose stem cells (ASCs), ECs and immune cells, each expressing NPY or its Rs. "Stressed" ASCs show both increased adipogenic potential and upregulated NPY system. In human Y2Rpositive fat grafted into nude mice, elevated NPY induces vascularization and long-lasting graft survival. These and new data of epigenetic regulation of NPY, prompted us to hypothesize that stress epigenetically upregulates the NPY system in ASCs, increasing adipogenic potential of "stressed" fat, specifically abdominal, accelerating diet-induced obesity and MetSyn. Inhibition of Y2Rs or altering DNA methylation of these or other adipogenic genes - inhibits these processes. We will use genetically modified mice, transfer of fat/ASCs between stressed and non-stressed mice, state-of-the-art 3D fat imaging, genome-wide epigenetic analyses, and relate the results to changes in human ASCs, stressed in vitro or in vivo, in nude mice.
Obesity is on the rise and with it, the risk of cardiovascular diseases. Our previous work have showed that stress may play a role by stimulating fat growth directly through nerves, which secrete Neuropeptide Y, a chemical causing ingrowth of new vessels and fat expansion. Identifying cellular molecular mechanisms of stress actions may lead to better ways of prevention or treatment of obesity and cardiovascular diseases.
|Han, Ruijun; Li, Aiyun; Li, Lijun et al. (2012) Maternal low-protein diet up-regulates the neuropeptide Y system in visceral fat and leads to abdominal obesity and glucose intolerance in a sex- and time-specific manner. FASEB J 26:3528-36|
|Hirsch, Dalay; Zukowska, Zofia (2012) NPY and stress 30 years later: the peripheral view. Cell Mol Neurobiol 32:645-59|
|Li, Lijun; Najafi, Amir H; Kitlinska, Joanna B et al. (2011) Of mice and men: neuropeptide Y and its receptors are associated with atherosclerotic lesion burden and vulnerability. J Cardiovasc Transl Res 4:351-62|
|Rasmusson, Ann M; Schnurr, Paula P; Zukowska, Zofia et al. (2010) Adaptation to extreme stress: post-traumatic stress disorder, neuropeptide Y and metabolic syndrome. Exp Biol Med (Maywood) 235:1150-62|
|Abe, Ken; Kuo, Lydia; Zukowska, Zofia (2010) Neuropeptide Y is a mediator of chronic vascular and metabolic maladaptations to stress and hypernutrition. Exp Biol Med (Maywood) 235:1179-84|
|Egan, Rupert J; Bergner, Carisa L; Hart, Peter C et al. (2009) Understanding behavioral and physiological phenotypes of stress and anxiety in zebrafish. Behav Brain Res 205:38-44|
|Ruohonen, Suvi T; Abe, Ken; Kero, Mia et al. (2009) Sympathetic nervous system-targeted neuropeptide Y overexpression in mice enhances neointimal formation in response to vascular injury. Peptides 30:715-20|
|Baker, Stephen B; Cohen, Michael; Kuo, Lydia et al. (2009) The role of the neuropeptide Y2 receptor in liporemodeling: neuropeptide Y-mediated adipogenesis and adipose graft maintenance. Plast Reconstr Surg 123:486-92|
|Pons, Jennifer; Kitlinska, Joanna; Jacques, Danielle et al. (2008) Interactions of multiple signaling pathways in neuropeptide Y-mediated bimodal vascular smooth muscle cell growth. Can J Physiol Pharmacol 86:438-48|
|Kuo, Lydia E; Czarnecka, Magdalena; Kitlinska, Joanna B et al. (2008) Chronic stress, combined with a high-fat/high-sugar diet, shifts sympathetic signaling toward neuropeptide Y and leads to obesity and the metabolic syndrome. Ann N Y Acad Sci 1148:232-7|
Showing the most recent 10 out of 20 publications