Identifying Ligand Binding Conformations of the β2-Adrenergic Receptor by Using Its Agonists as Computational Probes

Recently available G-protein coupled receptor (GPCR) structures and biophysical studies suggest that the difference between the effects of various agonists and antagonists cannot be explained by single structures alone, but rather that the conformational ensembles of the proteins need to be considered. Here we use an elastic network model-guided molecular dynamics simulation protocol to generate an ensemble of conformers of a prototypical GPCR, β2-adrenergic receptor (β2AR). The resulting conformers are clustered into groups based on the conformations of the ligand binding site, and distinct conformers from each group are assessed for their binding to known agonists of β2AR. We show that the select ligands bind preferentially to different predicted conformers of β2AR, and identify a role of β2AR extracellular region as an allosteric binding site for larger drugs such as salmeterol. Thus, drugs and ligands can be used as "computational probes" to systematically identify protein conformers with likely biological significance. © 2012 Isin et al

Big Data, Sentiment Analysis, and Examples during the COVID-19 Pandemic

Applied research in Big Data has gained popularity and is already transforming corporations, public sector, health care and subsequently everyday life. Big Data are being analysed for a variety of reasons, e.g., predict Brexit negotiating outcomes, optimise operations in agriculture, map and analyse human mobility trends under non-pharmaceutical interventions during the recent pandemic. The period of the COVID-19 pandemic has been characterised also by an ‘infodemic’, meaning an overabundance of both good and bad information. This information needs to be managed effectively as it can yield valuable insights when analysed. In this paper the terms of Big Data, Geospatial Big Data and Sentiment Analysis are presented along with selected cases, from the international literature, of the use of Big Data and analytics during the COVID-19 pandemic

Rational design, efficient syntheses and biological evaluation of N,N′-symmetrically bis-substituted butylimidazole analogs as a new class of potent Angiotensin II receptor blockers

A series of symmetrically bis-substituted imidazole analogs bearing at the N-1 and N-3 two biphenyl moieties ortho substituted either with tetrazole or carboxylate functional groups was designed based on docking studies and utilizing for the first time an extra hydrophobic binding cleft of AT1 receptor. The synthesized analogs were evaluated for their in vitro antagonistic activities (pA2 values) and binding affinities (–logIC50 values) to the Angiotensin II AT1 receptor. Among them, the potassium (–logIC50 = 9.04) and the sodium (–logIC50 = 8.54) salts of 4-butyl-N,N′-bis{[2′-(2H-tetrazol-5-yl)biphenyl-4-yl]methyl}imidazolium bromide (12a and 12b, respectively) as well as its free acid 11 (–logIC50 = 9.46) and the 4-butyl-2-hydroxymethyl-N,N′-bis{[2′-(2H-tetrazol-5-yl)biphenyl-4-yl]methyl}imidazolium bromide (14) (–logIC50 = 8.37, pA2 = 8.58) showed high binding affinity to the AT1 receptor and high antagonistic activity (potency). The potency was similar or even superior to that of Losartan (–logIC50 = 8.25, pA2 = 8.25). On the contrary, 2-butyl-N,N′-bis{[2′-[2H-tetrazol-5-yl)]biphenyl-4-yl]methyl}imidazolium bromide (27) (–logIC50 = 5.77) and 2-butyl-4-chloro-5-hydroxymethyl-N,N′-bis{[2′-[2H-tetrazol-5-yl)]biphenyl-4-yl]methyl}imidazolium bromide (30) (–logIC50 = 6.38) displayed very low binding affinity indicating that the orientation of the n-butyl group is of primary importance. Docking studies of the representative highly active 12b clearly showed that this molecule has an extra hydrophobic binding feature compared to prototype drug Losartan and it fits to the extra hydrophobic cavity. These results may contribute to the discovery and development of a new class of biologically active molecules through bis-alkylation of the imidazole ring by a convenient and cost effective synthetic strategy

Novel peptidomimetics related to Gonadotropin releasing hormone (GnRH)

Novel GnRH I and II analogues were designed and synthesized by Solid Phase Peptides Synthesis (SPPS), since GnRH has antiproliferative property, but poor metabolic stability. To rationalize synthetic difficulties, molecular dynamics simulations were performed, showing the conformational behavior of three derivatives. Among the two peptidomimetics series (Ie,f and IIe,f , GnRH I and GnRH II analogues respectively) several compounds (Id-f and IIc-e) showed a significant binding affinity. In particular, derivative Ie has an increased metabolic stability with respect to the physiological ligand (Ie t1/2= 3.96 h versus GnRH I t1/2 = 2.63 h)

Safety and efficacy of sofosbuvir‐containing regimens in hepatitis C‐infected patients with impaired renal function

BACKGROUND & AIMS: Renal clearance is the major elimination pathway for sofosbuvir (SOF). We assessed the safety and efficacy of SOF-containing regimens in patients with varying baseline estimated glomerular filtration rate (eGFR). METHODS: HCV-TARGET database is a multicentre, longitudinal 'real-world' treatment cohort. RESULTS: A total of 1789 patients [genotypes 1 (72%), 2 (17%) 3 (9%), 4-6 (2%)] had baseline eGFR determination: 73 with eGFR≤45 (18 with eGFR≤30, 5 on dialysis) were compared to 1716 with eGFR>45 ml/min/1.73 m(2) . Patients with baseline eGFR≤45 vs. >45 differed in being female (55% vs. 36%), age ≥65 years (24% vs. 16%), Black race (22% vs. 12%), having cirrhosis with decompensation (73% vs. 24%) and being post-transplant (49% vs. 10%), all P < 0.05. All patients with eGFR≤45 were treated with SOF 400 mg/day (including those on haemodialysis) and had median starting ribavirin (RBV) dose of 800 mg (IQR: 400-1200). Sustained virologic response (SVR) frequencies were similar across eGFR groups, ranging from 82-83%. Patients with eGFR ≤45 more frequently experienced anaemia, worsening renal function and serious AEs (all P < 0.05), and these associations persisted when limiting analysis to RBV-free regimens. Patients with baseline eGFR≤30 and eGFR 31-45 had similar frequencies of efficacy and safety outcomes. CONCLUSIONS: Sustained viral clearance was achieved in 83% of patients with renal impairment (eGFR ≤45 ml/min/1.73 m(2) ) treated with SOF-containing regimens. However, these patients had higher rates of anaemia, worsening renal dysfunction and serious adverse events regardless of use of RBV. Patient with renal impairment require close monitoring and should be treated by providers extensively experienced with SOF-containing regimens

A novel role of peripheral corticotropin-releasing hormone (CRH) on dermal fibroblasts

Corticotropin-releasing hormone, or factor, (CRH or CRF) exerts important biological effects in multiple peripheral tissues via paracrine/autocrine actions. The aim of our study was to assess the effects of endogenous CRH in the biology of mouse and human skin fibroblasts, the primary cell type involved in wound healing. We show expression of CRH and its receptors in primary fibroblasts, and we demonstrate the functionality of fibroblast CRH receptors by induction of cAMP. Fibroblasts genetically deficient in Crh (Crh-/-) had higher proliferation and migration rates and compromised production of IL-6 and TGF-beta1 compared to the wildtype (Crh+/+) cells. Human primary cultures of foreskin fibroblasts exposed to the CRF(1) antagonist antalarmin recapitulated the findings in the Crh-/- cells, exhibiting altered proliferative and migratory behavior and suppressed production of IL-6. In conclusion, our findings show an important role of fibroblast-expressed CRH in the proliferation, migration, and cytokine production of these cells, processes associated with the skin response to injury. Our data suggest that the immunomodulatory effects of CRH may include an important, albeit not explored yet, role in epidermal tissue remodeling and regeneration and maintenance of tissue homeostasis.PLoS On

Evaluation of a stable Gonadotropin-Releasing Hormone analog in mice for the treatment of endocrine disorders and prostate cancer

Gonadotropin-releasing hormone (GnRH) receptor agonists have wide clinical applications including the treatment of prostate cancer and endocrine disorders. However, such agonists are characterized by poor pharmacokinetic properties, often requiring repeated administration or special formulations. Therefore, the development of novel peptide analogs with enhanced in vivo stability could potentially provide therapeutic alternatives. The pharmacological evaluation of a bioactive peptide [Des-Gly10,Tyr5(OMe),D-Leu 6,Aze-NHEt9]GnRH, analog 1, is presented herein and compared with leuprolide. Peptide stability was evaluated using mouse kidney membrane preparations, followed by a liquid chromatography-tandem mass spectrometry-based approach that afforded identification and quantification of its major metabolites. The analog was significantly more stable in vitro in comparison with leuprolide. In vitro and in vivo stability results correlated well, encouraging us to develop a clinically relevant pharmacokinetic mouse model, which facilitated efficacy measurements using testosterone as a biomarker. Analog 1, an agonist of the GnRH receptor with a binding affinity in the nanomolar range, caused testosterone release in mice that was acutely dose-dependent, an effect blocked by the GnRH receptor antagonist cetrorelix. Repeated dosing studies in mice demonstrated that analog 1 was well tolerated and had potency similar to that of leuprolide, based on plasma and testis testosterone reduction and histopathological findings. Analog 1 also shared with leuprolide similar significant antiproliferative activity on androgen-dependent prostate cancer (LNCaP) cells. On the basis of pharmacokinetic advantages, we expect that analog 1 or analogs based on this new design will be therapeutically advantageous for the treatment of cancer and endocrine disorders. Copyrigh

GnRH-gemcitabine conjugates for the treatment of androgen-independent prostate cancer : pharmacokinetic enhancements combined with targeted drug delivery

Gemcitabine, a drug with established efficacy against a number of solid tumors, has therapeutic limitations due to its rapid metabolic inactivation. The aim of this study was the development of an innovative strategy to produce a metabolically stable analogue of gemcitabine that could also be selectively delivered to prostate cancer (CaP) cells based on cell surface expression of the Gonadotropin Releasing Hormone- Receptor (GnRH-R). The synthesis and evaluation of conjugated molecules, consisting of gemcitabine linked to a GnRH agonist, is presented along with results in androgen-independent prostate cancer models. NMR and ligand binding assays were employed to verify conservation of microenvironments responsible for binding of novel GnRH-gemcitabine conjugates to the GnRH-R. In vitro cytotoxicity, cellular uptake and metabolite formation of the conjugates were examined in CaP cell lines. Selected conjugates were efficacious in the in vitro assays with one of them, namely GSG, displaying high antiproliferative activity in CaP cell lines along with significant metabolic and pharmacokinetic advantages in comparison to gemcitabine. Finally, treatment of GnRH-R positive xenografted mice with GSG, showed a significant advantage in tumor growth inhibition when compared to gemcitabine.A.G.Leventis foundation and the General Secretariat for Research & Technology of the Greek Ministry of Education (LS7- 1682/17156/6.12.10).MRC and National Research Foundation of South Africa, and the Universities of Pretoria and Cape Townhttp://pubs.acs.org/bc2015-02-28hb201

A Novel Role of Peripheral Corticotropin-Releasing Hormone (CRH) on Dermal Fibroblasts

Corticotropin-releasing hormone, or factor, (CRH or CRF) exerts important biological effects in multiple peripheral tissues via paracrine/autocrine actions. The aim of our study was to assess the effects of endogenous CRH in the biology of mouse and human skin fibroblasts, the primary cell type involved in wound healing. We show expression of CRH and its receptors in primary fibroblasts, and we demonstrate the functionality of fibroblast CRH receptors by induction of cAMP. Fibroblasts genetically deficient in Crh (Crh−/−) had higher proliferation and migration rates and compromised production of IL-6 and TGF-β1 compared to the wildtype (Crh+/+) cells. Human primary cultures of foreskin fibroblasts exposed to the CRF1 antagonist antalarmin recapitulated the findings in the Crh−/− cells, exhibiting altered proliferative and migratory behavior and suppressed production of IL-6. In conclusion, our findings show an important role of fibroblast-expressed CRH in the proliferation, migration, and cytokine production of these cells, processes associated with the skin response to injury. Our data suggest that the immunomodulatory effects of CRH may include an important, albeit not explored yet, role in epidermal tissue remodeling and regeneration and maintenance of tissue homeostasis