This study aimed to determine the effect of neonatal feed restriction on plasma corticosterone concentration (CORT), hippocampal glucocorticoid receptor (GR) expression, and heat shock protein (Hsp) 70 expression in aged male Japanese quail subjected to acute heat stress. Equal numbers of chicks were subjected to either ad libitum feeding (AL) or 60% feed restriction on d 4, 5, and 6 (FR). At 21 (young) and 270 (aged) d of age, birds were exposed to 43 ± 1°C for 1 h. Blood and hippocampus samples were collected to determine CORT and Hsp 70 and GR expressions before heat stress and following 1 h of heat stress, 1 h of post-heat stress recovery, and 2 h of post-heat stress recovery. With the use of real-time PCR and enzyme immunoassay, we examined the hippocampal expression of GR and Hsp 70 and CORT. The GR expression of the young birds increased following heat stress and remained consistent throughout the period of recovery. Conversely, no significant changes were noted on GR expression of aged birds. Although both young and aged birds had similar CORT before and during heat stress, the latter exhibited greater values following 1 and 2 h of recovery. Within the young group, feeding regimens had no significant effect on Hsp 70 expression. However, neonatal feed restriction improved Hsp 70 expression in aged birds. Neonatal feed restriction, compared with the AL group, resulted in higher CORT on d 21 but the converse was noted on d 270. Neonatal feed restriction appears to set a robust reactive hypothalamo-pituitary-adrenal response allowing the development of adaptive, healthy, and resilient phenotypes in aged quail as measured by a higher hippocampal Hsp 70 expression along with lower CORT.
BackgroundPregnant women at a high risk of preterm delivery receive glucocorticoids to accelerate fetal lung maturation and surfactant synthesis. However, the effect of antenatal steroids on the developing diaphragm remains unclear. We hypothesized that maternal betamethasone impairs the fetal diaphragm, and the magnitude of the detrimental effect increases with longer duration of exposure. We aimed to determine how different durations of fetal exposure to maternal betamethasone treatment influence the fetal diaphragm at the functional and molecular levels.MethodsDate-mated merino ewes received intramuscular injections of saline (control) or two doses of betamethasone (5.7 mg) at an interval of 24 h commencing either 2 or 14 days before delivery. Preterm lambs were killed after cesarean delivery at 121-day gestational age. In vitro contractile measurements were performed on the right hemidiaphragm, whereas molecular/cellular analyses used the left costal diaphragm.ResultsDifferent durations of fetal exposure to maternal betamethasone had no consistent effect on the protein metabolic pathway, expression of glucocorticoid receptor and its target genes, cellular oxidative status, or contractile properties of the fetal lamb diaphragm.ConclusionThese data suggest that the potential benefits of betamethasone exposure on preterm respiratory function are not compromised by impaired diaphragm function after low-dose maternal intramuscular glucocorticoid exposure.
Glucocorticoids (GCs) and topoisomerase II inhibitors are used to treat acute lymphoblastic leukaemia (ALL) as they induce death in lymphoid cells through the glucocorticoid receptor (GR) and p53 respectively. Mechanisms underlying ALL cell death and the contribution of the bone marrow microenvironment to drug response/resistance remain unclear. The role of the microenvironment and the identification of chemoresistance determinants were studied by transcriptomic analysis in ALL cells treated with Dexamethasone (Dex), and Etoposide (Etop) grown in the presence or absence of bone marrow conditioned media (CM). The necroptotic (RIPK1) and the apoptotic (caspase-8/3) markers were downregulated by CM, whereas the inhibitory effects of chemotherapy on the autophagy marker Beclin-1 (BECN1) were reduced suggesting CM exerts cytoprotective effects. GCs upregulated the RIPK1 ubiquitinating factor BIRC3 (cIAP2), in GC-sensitive (CEM-C7-14) but not in resistant (CEM-C1-15) cells. In addition, CM selectively affected GR phosphorylation in a site and cell-specific manner. GR is recruited to RIPK1, BECN1 and BIRC3 promoters in the sensitive but not in the resistant cells with phosphorylated GR forms being generally less recruited in the presence of hormone. FACS analysis and caspase-8 assays demonstrated that CM promoted a pro-survival trend. High molecular weight proteins reacting with the RIPK1 antibody were modified upon incubation with the BIRC3 inhibitor AT406 in CEM-C7-14 cells suggesting that they represent ubiquitinated forms of RIPK1. Our data suggest that there is a correlation between microenvironment-induced ALL proliferation and altered response to chemotherapy.
Interacting effects of feeding and stress on corticoid responses in fish were investigated in common carp fed 3.0% or 0.5% body mass (BM) which received no implant, a sham or a cortisol implant (250 mg/kg BM) throughout a 168 hour post-implant period (168 h-PI). At 12h-PI, cortisol implants elevated plasma cortisol, glucose and lactate. Plasma osmolality and ions remained stable, but cortisol increased gill and kidney Na(+)/K(+) ATPase (NKA) and H(+) ATPase activities. Gill NKA activities were higher at 3%-BM, whereas kidney H(+) ATPase activity was greater at 0.5%-BM. Cortisol induced liver protein mobilization and repartitioned liver and muscle glycogen. At 3%-BM, this did not increase plasma ammonia, reflecting improved excretion efficiency concomitant with upregulation of Rhesus glycoprotein Rhcg-1 in gill. Responses in glucocorticoid receptors (GR1/GR2) and mineralocorticoid receptor (MR) to cortisol elevation were most prominent in kidney with increased expression of all receptors at 24 h-PI at 0.5%-BM, but only GR2 and MR at 0.5%-BM. In the liver, upregulation of all receptors occurred at 24 h-PI at 3%-BM, whilst only GR2 and MR were upregulated at 0.5%-BM. In the gill, there was a limited upregulation: GR2 and MR at 72 h-PI and GR1 at 168 h-PI at 3%-BM but only GR2 at 72 h-PI at 0.5%-BM. Thus cortisol elevation led to similar expression patterns of cortisol receptors in both feeding regimes, while feeding affected the type of receptor that was induced. Induction of corticoid receptors occurred simultaneously with increases in Rhcg-1 mRNA expression (gill) but well after NKA and H(+) ATPase activities increased (gill/kidney).