Role of NF-kappa B in Platelet Function
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Authors: Kojok, Kevin; El-Kadiry, Abed El-Hakim; Merhi, Yahye
Abstract
Platelets are megakaryocyte-derived fragments lacking nuclei and prepped to maintain primary hemostasis by initiating blood clots on injured vascular endothelia. Pathologically, platelets undergo the same physiological processes of activation, secretion, and aggregation yet with such pronouncedness that they orchestrate and make headway the progression of atherothrombotic diseases not only through clot formation but also via forcing a pro-inflammatory state. Indeed, nuclear factor-kappa B (NF-kappa B) is largely implicated in atherosclerosis and its pathological complication in atherothrombotic diseases due to its transcriptional role in maintaining pro-survival and pro-inflammatory states in vascular and blood cells. On the other hand, we know little on the functions of platelet NF-kappa B, which seems to function in other non-genomic ways to modulate atherothrombosis. Therein, this review will resemble a rich portfolio for NF-kappa B in platelets, specifically showing its implications at the levels of platelet survival and function. We will also share the knowledge thus far on the effects of active ingredients on NF-kappa B in general, as an extrapolative method to highlight the potential therapeutic targeting of NF-kappa B in coronary diseases. Finally, we will unzip a new horizon on a possible extra-platelet role of platelet NF-kappa B, which will better expand our knowledge on the etiology and pathophysiology of atherothrombosis.
Adipocyte-specific expression of C-type natriuretic peptide suppresses lipid metabolism and adipocyte hypertrophy in adipose tissues in mice fed high-fat diet
SCIENTIFIC REPORTS
Authors: Bae, Cho-Rong; Hino, Jun; Hosoda, Hiroshi; Son, Cheol; Makino, Hisashi; Tokudome, Takeshi; Tomita, Tsutomu; Hosoda, Kiminori; Miyazato, Mikiya; Kangawa, Kenji
Abstract
C-type natriuretic peptide (CNP) is expressed in diverse tissues, including adipose and endothelium, and exerts its effects by binding to and activating its receptor, guanylyl cyclase B. Natriuretic peptides regulate intracellular cGMP and phosphorylated vasodilator-stimulated phosphoprotein (VASP). We recently revealed that overexpression of CNP in endothelial cells protects against high-fat diet (HFD)induced obesity in mice. Given that endothelial CNP affects adipose tissue during obesity, CNP in adipocytes might directly regulate adipocyte function during obesity. Therefore, to elucidate the effect of CNP in adipocytes, we assessed 3T3-L1 adipocytes and transgenic (Tg) mice that overexpressed CNP specifically in adipocytes (A-CNP). We found that CNP activates the cGMP-VASP pathway in 3T3-L1 adipocytes. Compared with Wt mice, A-CNP Tg mice showed decreases in fat weight and adipocyte hypertrophy and increases in fatty acid beta-oxidation, lipolysis-related gene expression, and energy expenditure during HFD-induced obesity. These effects led to decreased levels of the macrophage marker F4/80 in the mesenteric fat pad and reduced inflammation. Furthermore, A-CNP Tg mice showed improved glucose tolerance and insulin sensitivity, which were associated with enhanced insulin-stimulated Akt phosphorylation. Our results suggest that CNP overexpression in adipocytes protects against adipocyte hypertrophy, excess lipid metabolism, inflammation, and decreased insulin sensitivity during HFD-induced obesity.