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

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

Ανίχνευση υποδοχέων σωματοστατίνης στον αμφιβληστροειδή: διαλυτοποίηση και βιοχημικός χαρακτηρισμός του υποδοχέα

The present study revealed the presence of specific binding sites for somatostatin in the rabbit retina. These were solubilized in an active form using the detergents, chaps and octyl-glucoside in the presence of additional phospholipids and glycerol. The physiochemical properties of the solubilized somatostatinergic receptors were examined. These revealed that the receptors are N-glycozylated proteins coupled to G-proteins, have different molecular weights(27-60kd)and two different pi values. The pharmacological as well as the physicochemical properties of the retinal somatostatinergic receptors sugget the presence of different receptor-subtypes.Η παρούσα διατριβή εξακρίβωσε την ύπαρξη εκλεκτικών θέσεων δέσμευσης της σωματοστατίνης στον αμφιβληστροειδή κουνελιού και κατόρθωσε να διαλυτοποιήσει αυτές σε λειτουργική μορφή με τη χρήση των απορρυπαντικών Chaps και OKTYL-γλυκοσίδης παρουσία εξωγενών φωσφολιπιδίων και γλυκερόλης. Η μελέτη των φυσικοχημικών ιδιοτήτων των διαλυτών υποδοχέων της σωματοστατίνης απεκάλυψε ότι αυτοί είναι Ν-γλυκοζυλιωμένες πρωτεϊνες που συνδεόμενες με τις G-πρωτεϊνες εμφανίζονται με μοριακά βάρη από 27 έως 60kd και με δύο διαφορετικές τιμές ισοηλεκτρικών σημείων. Τόσο οι φαρμακιλογικές όσο και οι φυσικοχημικές ιδιότητες των υποδοχέων της σωματοστατίνης του αμφιβληστροειδούς οδηγούν στο συμπέρασμα της πιθανής ύπαρξης διαφορετικών υποτύπων τους

Analgesic and Anti-Inflammatory Effects of the Synthetic Neurosteroid Analogue BNN27 during CFA-Induced Hyperalgesia

Dehydroepiandrosterone (DHEA), an adrenal and neurosteroid hormone with strong neuroprotective and immunomodulatory properties, and ligand for all high-affinity neurotrophin tyrosine kinase receptors (Trk), also exerts important effects on hyperalgesia. Its synthetic, 17-spiro-epoxy analogue, BNN27, cannot be converted to estrogen or androgen as DHEA; it is a specific agonist of TrkA, the receptor of pain regulator Nerve Growth Factor (NGF), and it conserves the immunomodulatory properties of DHEA. Our study aimed to evaluate the anti-nociceptive and anti-inflammatory properties of BNN27 during Complete Freund’s Adjuvant (CFA)-induced inflammatory hyperalgesia in mice. Hyperalgesia was evaluated using the Hargreaves test. Inflammatory markers such as cytokines, NGF and opioids were measured, additionally to corticosterone and the protein kinase B (AKT) signaling pathway. We showed for the first time that treatment with BNN27 reversed hyperalgesia produced by CFA. The effect of BNN27 involved the inhibition of NGF in the dorsal root ganglia (DRG) and the increased synthesis of opioid peptides and their receptors in the inflamed paw. We also found alterations in the cytokine levels as well as in the phosphorylation of AKT2. Our findings strongly support that BNN27 represents a lead molecule for the development of analgesic and anti-inflammatory compounds with potential therapeutic applications in inflammatory hyperalgesia

Pharmaceutical compositions for antihypertensive treatments: a patent review

Introduction: New drug formulations against hypertension have a vital role in the quality of human life, as this risk factor for cardiovascular disease can be life threatening. A modern life style characterized by less exercise, smoking, drinking and poor diet has increased the risk of developing hypertension, the so-called silent killer, in civilized communities and thus an urgent defense is needed against this enemy. Areas covered: In this review, the authors provide extensive information on pharmaceutical formulations containing anti-hypertensive drugs, as well as on general and specific patents. Thus, readers can understand the advances and new trends in the field. Expert opinion: A considerable effort has been made to provide new and improved formulations, comprising anti-hypertensive drugs with new excipients, appropriate particle size, containing alkaline salts or included in cyclodextrins in an attempt to avoid known existing problems. New types of formulations are expected to emerge in the near future that will allow for more effective and spatiotemporally controlled drug delivery, which will be better tolerated by the patients and will provide better pharmaceutical treatment. Such an example is the new cocktail formulations that contain more than one active component, act synergistically and therefore have optimized pharmacological benefits. Formulations using multitarget antihypertensive drugs are also expected to be commercially available in the near future

Family B G Protein-coupled Receptors and their Ligands: From Structure to Function

Background: Family B G protein-coupled receptors (GPCRs) play an important role in many physiological and pathophysiological processes. They are plasma-membrane proteins containing an extracellular N-domain, an intracellular C-tail, seven transmembrane domains (TMs), three extracellular (ELs) and three intracellular (ILs) loops. Objective: This review aims to summarize the current structural and functional information for family B GPCRs and their ligands, as well as, their physiological and pathophysiological role. Methods: Α thorough search of bibliographic databases for peer-reviewed research literature was undertaken. Moreover, molecular models of family B GPCRs were constructed and a structural alignment of their amino acid sequences was performed to demonstrate common structural characteristics. Results: In this review the family B GPCRs and their complexes with the receptor activity modifying proteins (RAMPs) were classified into five groups and the important physiological and pathophysiological role of these receptors was summarized. In addition, conserved residues of the Ndomain and the TMs of these receptors were numbered, thus making feasible the comparison of receptor structures and demonstrating common structural characteristics that are functionally important for all family B receptors. Molecular models created in this study were used to discuss the molecular mechanisms underlying ligand binding to family B GPCRs and receptor activation. Conclusion: The findings of this review provide information about the structural-functional determinants of family B GPCRs and their ligands, thus boosting the design of novel drugs with better potencies and bioavailabilities, which might enrich the therapeutic armory for the treatment of a wide spectrum of family B GPCRs-related disorders

Structural and Functional Insights into CRF Peptides and Their Receptors

Corticotropin-releasing factor or hormone (CRF or CRH) and the urocortins regulate a plethora of physiological functions and are involved in many pathophysiological processes. CRF and urocortins belong to the family of CRF peptides (CRF family), which includes sauvagine, urotensin, and many synthetic peptide and non-peptide CRF analogs. Several of the CRF analogs have shown considerable therapeutic potential in the treatment of various diseases. The CRF peptide family act by interacting with two types of plasma membrane proteins, type 1 (CRF1R) and type 2 (CRF2R), which belong to subfamily B1 of the family B G-protein-coupled receptors (GPCRs). This work describes the structure of CRF peptides and their receptors and the activation mechanism of the latter, which is compared with that of other GPCRs. It also discusses recent structural information that rationalizes the selective binding of various ligands to the two CRF receptor types and the activation of receptors by different agonists