Synthesis and evaluation of prodrugs of corticotropin-releasing factor-1 (CRF1) receptor antagonist BMS-665053 leading to improved oral bioavailability

A series of phosphate and ester-based prodrugs of anilinopyrazinone 1 (BMS-665053) containing either a methylene or an (acyloxy)alkoxy linker was prepared and evaluated in rat pharmacokinetic studies with the goal of improving the oral bioavailability of the parent (1). The prodrugs, in general, had improved aqueous solubility and oral bioavailability compared to 1. Prodrug 12, which contains an (acyloxy)alkoxy linker, showed the greatest improvement in the oral bioavailability relative to the parent (1), with a seven-fold increase (from 5% to 36%) in rat pharmacokinetic studies.     

Sprint interval training (SIT) is an effective method to maintain cardiorespiratory fitness (CRF) and glucose homeostasis in Scottish adolescents

The present study examined the physiological impact of a school based sprint interval training (SIT) intervention in replacement of standard physical education (SPE) class on cardio-respiratory fitness (CRF) and glucose homeostasis during the semester following summer vacation. Participants (n=49) were randomly allocated to either intervention (SIT; n=26, aged 16.9 ± 0.3 yrs) or control group who underwent standard physical education (SPE; n=23, aged 16.8 ± 0.6 yrs). CRF (VO₂max) and glucose homeostasis were obtained prior-to and following 7 weeks of SIT exercise. Significant group x time interaction was observed for CRF (P < 0.01) with non-significant trends for fasting insulin (P= 0.08), and HOMA-IR (P=0.06). CRF decreased (P < 0.01) in SPE such that POST intervention CRF was significantly lower (P< 0.05) in SPE. Fasting plasma glucose (P < 0.01), insulin (P< 0.01) and HOMA-IR (P< 0.01) increased significantly amongst SPE. The main finding of the present study is that 7-weeks of SIT exercise is an effective method of maintaining (but not improving) CRF and fasting insulin homeostasis amongst school-going adolescents. SIT exercise demonstrates potential as a time efficient physiological adjunct to standard PE class in order to maintain CRF during the school term.     

Sex differences in the effects of chronic stress and food restriction on body weight gain and brain expression of CRF and relaxin‐3 in rats

This study investigated sex‐specific effects of repeated stress and food restriction on food intake, body weight, corticosterone plasma levels and expression of corticotropin‐releasing factor (CRF) in the hypothalamus and relaxin‐3 in the nucleus incertus (NI). The CRF and relaxin‐3 expression is affected by stress, and these neuropeptides produce opposite effects on feeding (anorexigenic and orexigenic, respectively), but sex‐specific regulation of CRF and relaxin‐3 by chronic stress is not fully understood. Male and female rats were fed ad libitum chow (AC) or ad libitum chow and intermittent palatable liquid Ensure without food restriction (ACE), or combined with repeated food restriction (60% chow, 2 days per week; RCE). Half of the rats were submitted to 1‐h restraint stress once a week. In total, seven weekly cycles were applied. The body weight of the RCE stressed male rats significantly decreased, whereas the body weight of the RCE stressed female rats significantly increased compared with the respective control groups. The stressed female RCE rats considerably overate chow during recovery from stress and food restriction. The RCE female rats showed elevated plasma corticosterone levels and low expression of CRF mRNA in the paraventricular hypothalamic nucleus but not in the medial preoptic area. The NI expression of relaxin‐3 mRNA was significantly higher in the stressed RCE female rats compared with other groups. An increase in the expression of orexigenic relaxin‐3 and misbalanced hypothalamic‐pituitary‐adrenal axis activity may contribute to the overeating and increased body weight seen in chronically stressed and repeatedly food‐restricted female rats .     

肾性贫血红细胞膜蛋白巯基结合位置性质的ESR研究

用四种不同链长的马来酰亚胺氮氧自由基标记物研究了慢性肾衰竭(CRF)贫血病人红细胞膜蛋白巯基结合位置的性质。从所得的ESR波谱计算了弱、强固定化成分之比(W/S)。结果表明,由M(Ⅰ)、M(Ⅱ)和M(Ⅲ)标记病人红细胞膜所得的W/S值都比标记正常人红细胞膜得到的W/S位高(P<0.05),这说明慢性肾衰竭贫血病人红细胞膜蛋白的巯基结合位置的构象发生了变化;用M(Ⅳ)标记正常人红细胞和病人红细胞所得到的ESR波谱都只含有弱固定化波谱,没有强固定化波谱。得出的这个结果将为探讨CRF贫血的发病机理提供理论证据。     

Effect of Corticotropin Releasing Factor Injected Into the Median Eminence on Growth Hormone Secretion in Male Rats

We determined the dose-response relationship and examined the time-related effect of CRF (corticotropin releasing factor) injected directly into the Median Eminence (ME) on GH (growth hormone) secretion in conscious intact and castrated male rats. Doses of 0.25, 0.75, 1, and 1.5 nmol CRF dissolved in 1 l of saline, or saline alone in the controls, were injected into the ME, and blood samples collected through indweling catheters implanted in the jugular vein, 30, 60, 90, and 120 min post-injection to determine plasma GH levels by RIA. After 120 min the animals were decapitated. Trunk blood of decapitated animals was used to determine plasma testosterone and glucose levels. CRF at all the doses studied significantly decreased plasma GH in castrated and intact animals. The results suggest that in male as in female rats, CRF inhibits by itself GH secretion, at least in part, by a central action in the ME; all the doses of CRF studied suppressed GH secretion in castrated and intact males; finally, CRF at ME levels may participate in a variety of stress-related responses, including growth inhibition, through GH suppression.     

Crystal structure of a soluble decoy receptor IL-22BP bound to interleukin-22

Interleukin-22 (IL-22) plays an important role in the regulation of immune and inflammatory responses in mammals. The IL-22 binding protein (IL-22BP), a soluble receptor that specifically binds IL-22, prevents the IL-22/interleukin-22 receptor 1 (IL-22R1)/interleukin-10 receptor 2 (IL-10R2) complex assembly and blocks IL-22 biological activity. Here we present the crystal structure of the IL-22/IL-22BP complex at 2.75 Å resolution. The structure reveals IL-22BP residues critical for IL-22 binding, which were confirmed by site-directed mutagenesis and functional studies. Comparison of IL-22/IL-22BP and IL-22/IL-22R1 crystal structures shows that both receptors display an overlapping IL-22 binding surface, which is consistent with the inhibitory role played by IL-22 binding protein.

Structured summary

MINT-7010533: IL-22 BP (uniprotkb:Q969J5) and IL-22 (uniprotkb:Q9GZX6) bind (MI:0407) by X-ray crystallography (MI:0114)     

Urocortin 3 elevates cytosolic calcium in nucleus ambiguus neurons

J. Neurochem. (2012) 122, 1129-1136. ABSTRACT: Urocortin 3 (also known as stresscopin) is an endogenous ligand for the corticotropin-releasing factor receptor 2 (CRF(2) ). Despite predominant G(s) coupling of CRF(2) , promiscuous coupling with other G proteins has been also associated with the activation of this receptor. As urocortin 3 has been involved in central cardiovascular regulation at hypothalamic and medullary sites, we examined its cellular effects on cardiac vagal neurons of nucleus ambiguus, a key area for the autonomic control of heart rate. Urocortin 3 (1?nM-1000?nM) induced a concentration-dependent increase in cytosolic Ca(2+) concentration that was blocked by the CRF(2) antagonist K41498. In the case of two consecutive treatments with urocortin 3, the second urocortin 3-induced Ca(2+) response was reduced, indicating receptor desensitization. The effect of urocortin 3 was abolished by pre-treatment with pertussis toxin and by inhibition of phospolipase C with U-73122. Urocortin 3 activated Ca(2+) influx via voltage-gated P/Q-type channels as well as Ca(2+) release from endoplasmic reticulum. Urocortin 3 promoted Ca(2+) release via inositol 1,4,5 trisphosphate receptors, but not ryanodine receptors. Our results indicate a novel Ca(2+) -mobilizing effect of urocortin 3 in vagal pre-ganglionic neurons of nucleus ambiguus, providing a cellular mechanism for a previously reported role for this peptide in parasympathetic cardiac regulation.     

Therapeutic Anti-Depressant Potential of Microbial GABA Produced by Lactobacillus rhamnosus Strains for GABAergic Signaling Restoration and Inhibition of Addiction-Induced HPA Axis Hyperactivity

The role of the microbiota–gut–brain (MGB) axis in mood regulation and depression treatment has gained attention in recent years, as evidenced by the growing number of animal and human studies that have reported the anti-depressive and associated gamma-aminobutyric acid-ergic (GABAergic) effects of probiotics developed from Lactobacillus rhamnosus bacterial strains in the gut microbiome. The depressive states attenuated by these probiotics in patients suffering from clinical depression also characterize the severe and relapse-inducing withdrawal phase of the addiction cycle, which has been found to arise from the intoxication-enabled hyperregulation of the hypothalamic–pituitary–adrenal (HPA) axis, the body’s major stress response system, and a corresponding attenuation of its main inhibitory system, the gamma-aminobutyric acid (GABA) signaling system. Therefore, the use of probiotics in the treatment of general cases of depression provides hope for a novel therapeutic approach to withdrawal depression remediation. This review discusses potential therapeutic avenues by which probiotic application of Lactobacillus rhamnosus strains can be used to restore the central GABAergic activity responsible for attenuating the depression-inducing HPA axis hyperactivity in addiction withdrawal. Also, information is provided on brain GABAergic signaling from other known GABA-producing strains of gut microbiota.     

High affinity binding sites for somatostatin to rat pituitary

Binding sites for somatostatin (SS) are described in rat pituitary membranes using either [¹²⁵I-Tyr¹¹]-SS-14 or [Leu⁸, D-Trp²², ¹²⁵I-Tyr²⁵]-SS-28 as radioligands; in each case saturable and high affinity binding sites with K_D's for SS of 1.09 and 0.95 nM respectively have been characterized. The binding capacity is 100 f mols/mg protein. The potencies of various SS analogs measured in the radioreceptor assay are in agreement with the potencies in a bioassay measuring inhibition of growth hormone release; in particular, SS-28 is slightly less potent than SS-14. A comparison of these data with those describing SS binding in brain and pancreas suggests that some pharmacological differences may exist between pituitary, brain and pancreas binding sites for SS.