Single-Gene Congenic Strain Reveals the Effect of Zbtb16 on Dexamethasone-Induced Insulin Resistance

Abstract

BackgroundGlucocorticoids (GCs) are potent therapeutic agents frequently used for treatment of number of conditions, including hematologic, inflammatory, and allergic diseases. Both their therapeutic and adverse effects display significant interindividual variation, partially attributable to genetic factors. We have previously isolated a seven-gene region of rat chromosome 8 sensitizing to dexamethasone (DEX)-induced dyslipidemia and insulin resistance (IR) of skeletal muscle. Using two newly derived congenic strains, we aimed to investigate the effect of one of the prime candidates for this pharmacogenetic interaction, the Zbtb16 gene.MethodsAdult male rats of SHR-Lx.PD5PD-Zbtb16 (n = 9) and SHR-Lx.PD5SHR-Zbtb16 (n = 8) were fed standard diet (STD) and subsequently treated with DEX in drinking water (2.6 µg/ml) for 3 days. The morphometric and metabolic profiles of both strains including oral glucose tolerance test, triacylglycerols (TGs), free fatty acids, insulin, and C-reactive protein levels were assessed before and after the DEX treatment. Insulin sensitivity of skeletal muscle and visceral adipose tissue was determined by incorporation of radioactively labeled glucose.ResultsThe differential segment of SHR-Lx.PD5SHR-Zbtb16 rat strain spans 563 kb and contains six genes: Htr3a, Htr3b, Usp28, Zw10, Tmprss5, and part of Drd2. The SHR-Lx.PD5PD-Zbtb16 minimal congenic strain contains only Zbtb16 gene on SHR genomic background and its differential segment spans 254 kb. Total body weight was significantly increased in SHR-Lx.PD5PD-Zbtb16 strain compared with SHR-Lx.PD5SHR-Zbtb16, however, no differences in the weights of adipose tissue depots were observed. While STD-fed rats of both strains did not show major differences in their metabolic profiles, after DEX treatment the SHR-Lx.PD5PD-Zbtb16 congenic strain showed increased levels of TGs, glucose, and blunted inhibition of lipolysis by insulin. Both basal and insulin-stimulated incorporation of radioactively labeled glucose into skeletal muscle glycogen were significantly reduced in SHR-Lx.PD5PD-Zbtb16 strain, but the insulin sensitivity of adipose tissue was comparable between the two strains.ConclusionThe metabolic disturbances including impaired glucose tolerance, dyslipidemia, and IR of skeletal muscle observed after DEX treatment in the congenic SHR-Lx.PD5PD-Zbtb16 reveal the Zbtb16 locus as a possible sensitizing factor for side effects of GC therapy.

Glucocorticoid-dependent transcription in skin requires epidermal expression of the glucocorticoid receptor and is modulated by the mineralocorticoid receptor

“…It is known that the induction or repression of GC targets above or below proper threshold can contribute to detrimental effects of GC excess in several tissues. For example, up-regulation of Zbtb16 and Txnip / Vdup has been reported in bone tissue in Cushing patients 36 , 37 . It is also worth noting the high overlap between the DEGs identified in this study and the gene expression changes in human skin of aged vs young subjects 10 .…”

Grandmother’s Diet Matters: Early Life Programming with Sucrose Influences Metabolic and Lipid Parameters in Second Generation of Rats

“…We used the spontaneously hypertensive rat (SHR/OlaIpcv, RGD ID 631848) because of its inherent abnormal metabolic profile [21] and its sensitivity manipulation by diet [22]. The SHR-Lx.PD5 PD-Zbtb16 single congenic strain (SHR-Zbtb16 hereafter) was derived from polydactylous rat (PD/Cub, RGD ID 728161) [23] and carries the Zbtb16 gene of PD origin on the SHR genomic background [24,25]. Both strains are highly inbred and maintained by brother x sister mating at the Institute of Biology and Medical Genetics.…”

“…At that time, SHR and SHR-Zbtb16 male offspring of both control (n = 8/strain) and experimental (n = 8/strain) groups were subjected to OGTT, blood draw for metabolic and lipid profile assessment and sacrificed to determine the weights of heart, liver, kidneys, adrenals, interscapular brown fat, epididymal and retroperitoneal fat pads. The lipid profile was assessed using high performance liquid chromatography (HPLC) for determining triglyceride (TG) and cholesterol (C) concentrations in 20 lipoprotein fractions and the size of major classes of lipoprotein particles as described previously [25,26]. F1 rat dams (n = 7/strain) were weighed regularly and subjected to OGTT at 16 weeks of age to determine the differences in glucose tolerance after being metabolically programmed by their maternal diet-either STD or HSD.…”

Maternal High-Sucrose Diet Affects Phenotype Outcome in Adult Male Offspring: Role of Zbtb16

“…The SHR- Lx .PD5 PD– Zbtb16 single congenic strain (SHR- Zbtb16 hereafter) carries the Zbtb16 gene of polydactylous rat (PD/Cub, RGD ID 728161) origin on the SHR genomic background. The derivation of this strain was described previously ( Seda et al, 2005 ; Krupkova et al, 2018 ). Both strains are highly inbred and maintained by brother x sister mating at the Institute of Biology and Medical Genetics.…”

“…In addition to its role in adipogenesis, control of hepatic gluconeogenesis ( Chen et al, 2014 ), and cardiac hypertrophy ( Liska et al, 2017 ), genetic variation in human ZBTB16 was associated with increased obesity parameters and higher total and LDL cholesterol ( Bendlova et al, 2017 ). We have previously shown that rats carrying specific Zbtb16 allele are particularly sensitive to HSD, glucocorticoids, and retinoic acid in terms of induction of metabolic dysfunction ( Krupkova et al, 2014 , 2018 ). Therefore, we hypothesized that maternal HSD intake during pregnancy and lactation would program the offspring to develop metabolic alterations in adulthood and that these effects may be, to a certain extent, modified by genetic variation in Zbtb16 .…”