ISSN 2409-4943. Ukr. Biochem. J., 2019, Vol. 91, N 3 UDC 577.112:616 doi: https://doi.org/10.15407/ubj91.03.065 INSULIN RESISTANCE IN OBESE ADOLESCENTS AND ADULT MEN MODIFIES THE EXPRESSION OF PROLIFERATION RELATED GENES O.N H. MI CHENKO1, Y. M. VILETSKA1,N D. O. MI CHENKO1,2, V. V. DAVYDOV3 1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv; e-mail: [email protected]; 2Bohomolets National Medical University, Kyiv, Ukraine 3SI “Institute of Children and Adolescent Health Care, National Academy of Medical Sciences of Ukraine”, Kharkiv Received: 11 December 2018; Accepted: 14 March 2019 Numerous data demonstrate that key regulatory factors, enzymes and receptors including HSPA5, MEST, SLC1A3, PDGFC, and ADM represent poly-functional, endoplasmic reticulum stress-dependent pro- teins, which control variable metabolic pathways. The expression level of genes of these proteins in the blood and subcutaneous adipose tissue of obese adolescents and adult men with and without insulin resistance was studied. It was shown that in blood of obese adolescents without insulin resistance the expression level of SLC1A3, HSPA5, MEST, and PDGFC genes was significantly increased, but development of insulin resis tance led to down-regulation of these genes expression except HSPA5 gene as compared to the control group as well as to the group of obese adolescents without insulin resistance. At the same time, the expression level of ADM gene did not change significantly in obese adolescents without insulin resistance, but the develop- ment of insulin resistance led to down-regulation of this gene expression. In subcutaneous adipose tissue of obese adult men without insulin resistance the level of SLC1A3 gene expression was decreased, although ADM, MEST, and HSPA5 genes – increased. It was also shown that the development of insulin resistance in obese men affected the expression level of ADM and SLC1A3 genes only. Results of this investigation provide evidence that insulin resistance in obese adolescents and adult men is associated with specific changes in the expression of genes, which related to proliferation and development of obesity and insulin resistance as well as to endoplasmic reticulum stress and contribute to the development of obesity complications. K e y w o r d s: obesity, insulin resistance, gene expression, MEST, HSPA5, ADM, blood, adipose tissue. hildren with severe obesity are at greater bolic syndrome, results from interactions between risk for adult obesity, early atherosclerosis, genes and environmental factors and is associated C hypertension, metabolic syndrome, type 2 with changes in gene expressions of the regulatory diabetes, fatty liver disease and premature death [1]. network in various organs and tissues, but preferen- Thus, childhood obesity is a serious and urgent pub- tially in adipose tissue [5-8]. Adipose tissue growth lic health problem because the number of children is in the center of obesity and tightly associated with with severe obesity is significantly increased [1]. glucose and lipid metabolism as well as cell prolife- The development of obesity, as well as its metabolic ration processes and is controlled by various inter- complications, is associated with dysregulation of connected regulatory factors and enzymes [9]. At numerous intrinsic mechanisms, which control most the same time, the blood reflects numerous changes key metabolic processes, including proliferation, in different organs and tissues in various diseases glucose and lipid metabolism as well as insulin sen- including obesity [10, 11]. Special interest deserves sitivity [2-5]. Furthermore, obesity, as well as meta- the key regulatory factors, which control cell pro- © 2019 Minchenko O. H. et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 65 ISSN 2409-4943. Ukr. Biochem. J., 2019, Vol. 91, N 3 liferation, glucose and lipid metabolism as well as cal processes including embryonic development, an- endoplasmic reticulum stress [2, 4, 8, 12, 13]. Thus, giogenesis, cell proliferation and differentiation, and adolescent obesity is associated with increased ex- contribute to the pathophysiology of some diseases, pression of IRS1, ССN2, IGSEC, RSPO1, IL13RA2, including cancer [27]. It also plays an important role and RIPK2 genes and down-regulated IRS2 and in angiogenesis and blood vessel development, in- DNAJC15 gene expressions, although with insulin duces anti-apoptotic effects on macrophages through resistance is associated the expression IRS1, IRS2, Akt and Bad phosphorylation, but in the nucleus, DNAJC15, RSPO1, and RIPK2 genes only [13]. PDGFC seems to have additional function [17]. Numerous data clearly demonstrate that key Heat shock protein family А member 5 regulatory factors, enzymes and receptors inclu- (HSPA5) is a member of the heat shock protein 70 ding ADM (adrenomedullin), SLC1A3 (solute car- (HSP70) family and is localized in the lumen of the rier family 1, member 3: glial high-affinity gluta- endoplasmic reticulum. It is involved in the correct mate transporter), PDGFC (platelet-derived growth folding and assembly of proteins in the endoplasmic factor C), MEST (mesoderm specific transcript) reticulum as well as in the degradation of misfol- and HSPA5 (heat shock protein family A member ded proteins via its interaction with DNAJC10 [18]. 5) represent poly-functional, endoplasmic reticulum HSPA5 protein is also known as glucose-regulated stress-dependent proteins, which control variable 78kDa protein (GRP78) and immunoglobulin heavy metabolic pathways and are related to oncogenesis chain-binding protein (BiP) as well as endoplasmic [8, 14-19]. Therefore, adrenomedullin is a potent reticulum luminal Ca(2+)-binding protein grp78. It hypotensive peptide, which controls leptin, endothe- is a poly-functional protein, which also presents in lin-1, and adiponectin secretion as well as has re- a nucleus, mitochondrion and extracellular matrix, lation to the development of insulin resistance and participates in the control of various metabolic path- metabolic syndrome [20-23]. Moreover, the increase ways and plays an important role in endoplasmic in leptin and the decrease in adiponectin by ADM reticulum stress, obesity and insulin resistance as in the epididymal fat may have opposite effects on well as in adipogenesis and oncogenesis [18, 28-34]. metabolism [22]. Leptin is an important regulator Thus, the endoplasmic reticulum luminal co-chape- of adipose tissue growth and participates in various rone ERdj4/DNAJB9 is a selective IRE1 repressor signaling pathways including cell proliferation. It is that promotes a complex between the luminal HSP70 interesting to note that ADM is increased in tumors, BiP and the luminal stress-sensing domain of IRE1 promotes metastasis and has relation to oncogenesis [18]. Moreover, recently was shown that p53 targets [14, 15, 23]. Therefore, there is data that ADM and BiP to promote apoptosis during severe endoplasmic erythropoietin receptor may serve as new regulatory reticulum stress and that cell surface BiP/GRP78 fa- factors involved in angiogenesis of hepatocellular cilitates hepatoma cells proliferation and migration carcinoma [24]. by activating IGF-IR [30, 35]. SLC1A3 (solute carrier family 1 member 3) is Next poly-functional gene, which has relation a mitochondrial protein EAAT1 (excitatory amino to obesity, insulin resistance, and cell proliferation, acid transporters 1), which also known as glial high- is MEST (mesoderm specific transcript) [36-38]. affinity glutamate transporter (GLAST1), controls Thus, epigenetic malprogramming of MEST may transport of L-glutamate and also L- and D-aspartate contribute to obesity predisposition throughout life and is essential for terminating the postsynaptic ac- [36]. It is interesting to note that females are more tion of glutamate by rapidly removing released glu- protected from age-related metabolic disturbances, tamate from the synaptic cleft [16, 25, 26]. It is also such as insulin resistance, hepatic lipid deposition, localized in adipocytes and insulin, which coordi- and white adipose tissue inflammation compared to nates the catabolism of nutrients by protein phospho- males. This may be related to their greater capaci- rylation, controls the phosphorylation of the Glu/Asp ty for white adipose tissue expansion-reflected by transporter SLC1A3/EAAT1 in these cells [26]. Re- a greater MEST/LEPTIN mRNA ratio and to their cently was shown that a high-fat diet reduces the hip- ability to maintain adiponectin levels and preserve pocampal content level of lactate which is correlated leptin sensitivity with aging [37]. MEST is a stress with the expression of glial glutamate transporters responsible gene and strongly up-regulated in glio- [25]. Platelet-derived growth factor-C (PDGF-C), ma cells after inhibition of endoplasmic reticulum also known as VEGFE (vascular endothelial growth stress mediated by IRE1 signaling [39]. Moreover, factor E), has roles in the regulation of many biologi- the neuroanatomical and phenotypical consequences 66 O. H. Minchenko, Y. M. Viletska, D. O. Minchenko, V. V. Davydov detected upon the loss of MEST, resemble the loss of vided into three equal groups (7 subjects in each substantia nigra neurons and loss of movement con- group): one group of relative healthy individuals trol as seen in Parkinson's disease,