Structure-activity relationship study of central pyridine-derived TYK2 JH2 inhibitors: Optimization of the PK profile through C4' and C6 variations

Efforts directed at improving potency and preparing structurally different TYK2 JH2 inhibitors from the first generation of compounds such as 1a led to the SAR study of new central pyridyl based analogs 2-4. The current SAR study resulted in the identification of 4h as a potent and selective TYK2 JH2 inhibitor with distinct structural differences from 1a. In this manuscript, the in vitro and in vivo profiles of 4h are described. The hWB IC50 of 4h was shown as 41 nM with 94% bioavailability in the mouse PK study.

Discovery of BMS-753426: A Potent Orally Bioavailable Antagonist of CC Chemokine Receptor 2

To improve the metabolic stability profile of BMS-741672 (1a), we undertook a structure-activity relationship study in our trisubstituted cyclohexylamine series. This ultimately led to the identification of 2d (BMS-753426) as a potent and orally bioavailable antagonist of CCR2. Compared to previous clinical candidate 1a, the tert-butyl amine 2d showed significant improvements in pharmacokinetic properties, with lower clearance and higher oral bioavailability. Furthermore, compound 2d exhibited improved affinity for CCR5 and good activity in models of both monocyte migration and multiple sclerosis in the hCCR2 knock-in mouse. The synthesis of 2d was facilitated by the development of a simplified approach to key intermediate (4R)-9b that deployed a stereoselective reductive amination which may prove to be of general interest.

Azatricyclic Inverse Agonists of RORγt That Demonstrate Efficacy in Models of Rheumatoid Arthritis and Psoriasis

Structure-activity relationship studies directed toward the replacement of the fused phenyl ring of the lead hexahydrobenzoindole RORγt inverse agonist series represented by 1 with heterocyclic moieties led to the identification of three novel aza analogs 5-7. The hexahydropyrrolo[3,2-f]quinoline series 5 (X = N, Y = Z=CH) showed potency and metabolic stability comparable to series 1 but with improved in vitro membrane permeability and serum free fraction. This structural modification was applied to the hexahydrocyclopentanaphthalene series 3, culminating in the discovery of 8e as a potent and selective RORγt inverse agonist with an excellent in vitro profile, good pharmacokinetic properties, and biologic-like in vivo efficacy in preclinical models of rheumatoid arthritis and psoriasis.

Tricyclic-Carbocyclic RORγt Inverse Agonists-Discovery of BMS-986313

SAR efforts directed at identifying RORγt inverse agonists structurally different from our clinical compound 1 (BMS-986251) led to tricyclic-carbocyclic analogues represented by 3-7 and culminated in the identification of 3d (BMS-986313), with structural differences distinct from 1. The X-ray co-crystal structure of 3d with the ligand binding domain of RORγt revealed several key interactions, which are different from 1. The in vitro and in vivo PK profiles of 3d are described. In addition, we demonstrate robust efficacy of 3d in two preclinical models of psoriasis-the IMQ-induced skin lesion model and the IL-23-induced acanthosis model. The efficacy seen with 3d in these models is comparable to the results observed with 1.

Aryl Ether-Derived Sphingosine-1-Phosphate Receptor (S1P1) Modulators: Optimization of the PK, PD, and Safety Profiles

Efforts aimed at increasing the in vivo potency and reducing the elimination half-life of 1 and 2 led to the identification of aryl ether and thioether-derived bicyclic S1P₁ differentiated modulators 3-6. The effects of analogs 3-6 on lymphocyte reduction in the rat (desired pharmacology) along with pulmonary- and cardiovascular-related effects (undesired pharmacology) are described. Optimization of the overall properties in the aryl ether series yielded 3d, and the predicted margin of safety against the cardiovascular effects of 3d would be large enough for human studies. Importantly, compared to 1 and 2, compound 3d had a better profile in both potency (ED₅₀ < 0.05 mg/kg) and predicted human half-life (t _1/2 ∼ 5 days).

Use of a Conformational-Switching Mechanism to Modulate Exposed Polarity: Discovery of CCR2 Antagonist BMS-741672

We encountered a dilemma in the course of studying a series of antagonists of the G-protein coupled receptor CC chemokine receptor-2 (CCR2): compounds with polar C3 side chains exhibited good ion channel selectivity but poor oral bioavailability, whereas compounds with lipophilic C3 side chains exhibited good oral bioavailability in preclinical species but poor ion channel selectivity. Attempts to solve this through the direct modulation of physicochemical properties failed. However, the installation of a protonation-dependent conformational switching mechanism resolved the problem because it enabled a highly selective and relatively polar molecule to access a small population of a conformer with lower polar surface area and higher membrane permeability. Optimization of the overall properties in this series yielded the CCR2 antagonist BMS-741672 (7), which embodied properties suitable for study in human clinical trials.

Inhibition of matrix metalloproteins 9 attenuated Candida albicans induced inflammation in mouse cornea

Since the severe corneal ulceration of mouse cornea is known to occur with inflammation. As one of imperative matrix metalloproteinase, the potential roles of matrix metalloproteins 9 (MMP9) in corneal ulceration and keratitis are still unveiled caused by fungal invasion. In this study, Candida albicans (CA) inoculated wild-type KM mice cornea was used as a model pathogen in corneal inflammation.  CA invasion significantly stimulated the expression of collagen IV and MMP9 detected by RT-PCR, Real-time PCR and Immunofluorescent staining in mouse cornea as soon as 6 hours post infection, and relatively decreased at 1 day post infection. For examining the role of MMP9 in fungal keratitis, the mice corneas were subconjunctivally injected MMP9 antibody or recombinant MMP9 protein 6 hours prior to CA inoculation, using rabbit IgG as control. Subconjunctival injection of recombinant MMP9 protein prior to CA inoculation enhanced, whereas MMP9 antibody attenuated corneal ulceration and inflammation, examining basement membrane, fungal load, myeloperoxidase (MPO) and proinflammatory cytokines including Macrophage inflammatory protein 2 (MIP2), Interleukin-1β (IL-1β) and Tumor necrosis factor-α (TNF-α). Inhibition of MMP9 could potentially attenuate Candida albicans induced inflammation in mouse cornea.

Molecular and characterization of NnPPO cDNA from lotus (Nelumbo nucifera) in rhizome browning

The complete cDNA (NnPPO) of polyphenol oxidase in Nelumbo nucifera was successfully isolated, using Rapid amplification cDNA end (RACE) assays. The full-length cDNA of NnPPO was 2069 bp in size, containing a 1791 bp open reading frame coding 597 amino acids. The putative NnPPO possessed the conserved active sites and domains for PPO function. Phylogenetic analysis revealed that NnPPO shared high homology with PPO of high plants, and the homology modeling proved that NnPPO had the typical structure of PPO family. In order to characterize the role of NnPPO, Real-time PCR assay demonstrated that NnPPO mRNA was expressed in different tissues of N. nucifera including young leave, rhizome, flower, root and leafstalk, with the highest expression in rhizome. Patterns of NnPPO expression in rhizome illustrated its mRNA level was significantly elevated, which was consistent with the change of NnPPO activity during rhizome browning. Therefore, transcriptional activation of NnPPO was probably the main reason causing rhizome browning.

gamma-Lactams as glycinamide replacements in cyclohexane-based CC chemokine receptor 2 (CCR2) antagonists

We describe the design, synthesis, and evaluation, of gamma-lactams as glycinamide replacements within a series of di- and trisubstituted cyclohexane CCR2 antagonists. The lactam-containing trisubstituted cyclohexanes proved to be more potent than the disubstituted analogs, as trisubstituted analog, lactam 13, displayed excellent activity (CCR2 binding IC(50)=1.0 nM and chemotaxis IC(50) = 0.5 nM) and improved metabolic stability over its parent glycinamide.

The amyloid-beta rise and gamma-secretase inhibitor potency depend on the level of substrate expression

The amyloid-beta (Abeta) peptide, which likely plays a key role in Alzheimer disease, is derived from the amyloid-beta precursor protein (APP) through consecutive proteolytic cleavages by beta-site APP-cleaving enzyme and gamma-secretase. Unexpectedly gamma-secretase inhibitors can increase the secretion of Abeta peptides under some circumstances. This "Abeta rise" phenomenon, the same inhibitor causing an increase in Abeta at low concentrations but inhibition at higher concentrations, has been widely observed. Here we show that the Abeta rise depends on the beta-secretase-derived C-terminal fragment of APP (betaCTF) or C99 levels with low levels causing rises. In contrast, the N-terminally truncated form of Abeta, known as "p3," formed by alpha-secretase cleavage, did not exhibit a rise. In addition to the Abeta rise, low betaCTF or C99 expression decreased gamma-secretase inhibitor potency. This "potency shift" may be explained by the relatively high enzyme to substrate ratio under conditions of low substrate because increased concentrations of inhibitor would be necessary to affect substrate turnover. Consistent with this hypothesis, gamma-secretase inhibitor radioligand occupancy studies showed that a high level of occupancy was correlated with inhibition of Abeta under conditions of low substrate expression. The Abeta rise was also observed in rat brain after dosing with the gamma-secretase inhibitor BMS-299897. The Abeta rise and potency shift are therefore relevant factors in the development of gamma-secretase inhibitors and can be evaluated using appropriate choices of animal and cell culture models. Hypothetical mechanisms for the Abeta rise, including the "incomplete processing" and endocytic models, are discussed.

Design and synthesis of benzoazepinone-derived cyclic malonamides and aminoamides as potent γ-secretase inhibitors

We report the synthesis of benzoazepine-derived cyclic malonamides (2) and aminoamides (3) as gamma-secretase inhibitors for the potential treatment of Alzheimer's disease. The in vitro structure-activity relationships of 2 and 3 along with dog pharmacokinetic results are described.

Structure-based design of novel nonpeptide inhibitors of the Src SH2 domain: Phosphotyrosine mimetics exploiting multifunctional group replacement chemistry*

A series of novel nonpeptide inhibitors of the pp60(c-Src) (Src) SH2 domain is described that exploit multifunctional group replacement of the phenylphosphate moiety of phosphotyrosine (pTyr). Relative to an x-ray structure of citrate complexed to the pTyr binding site of the Src SH2 domain, these nonpeptide ligands illustrate the systematic replacement of the phosphate group by multiple nonhydrolyzable, mono- or dianionic functionalities. Specifically, several phenylalanine (Phe) analogs incorporating key 4' and 3' substituents were synthesized and incorporated into a bicyclic benzamide template previously reported (W. C. Shakespeare et al., Proceedings of the National Academy of Science USA, 2000, Vol. 97, pp. 9373-9378). These pTyr mimetics included 4',3'-diphosphono-Phe (Dpp), 4',3'-dicarboxymethyloxy-Phe (Dcp), and 4'-phosphono-3'-carboxymethyloxy-Phe (Cpp). Noteworthy were nonpeptide inhibitors 8-11 that were 5- to 10-fold more potent than the cognate tetrapeptide ligand Ac-pTyr-Glu-Glu-Ile-NH(2) in binding to the Src SH2 domain.

SRC homology-2 inhibitors: peptidomimetic and nonpeptide

The structural and functional characterization of Src homology-2 (SH2) domains and their relationship to catalytic proteins (e.g., kinases, phosphatases, and lipases) or non-catalytic proteins (e.g., upstream adapters, and downstream transcription factors) has significantly impacted our understanding of signal transduction pathways and the identification of promising therapeutic targets for drug discovery. Such SH2-containing proteins are known to be intimately involved in the regulation of a number of cellular processes, including growth, mitogenesis, motility, metabolism, and gene transcription. Molecular recognition and biochemical selectivity exists for various SH2 domains based on their binding to phosphotyrosine (pTyr) and contiguous C-terminal amino acids of cognate protein 'partners' in a sequence-dependent manner (i.e., -pTyr-AA(1)-AA(2)-AA(3)-) which result in the formation of signal transduction protein complexes in cells. In recent years, drug discovery efforts have advanced peptidomimetic and nonpeptide inhibitors of such protein-protein interactions based on mimicking pTyr-containing peptide ligands as well as SH2 structure-based de novo design of nonpeptide templates that can capture key binding sites on the target protein. Noteworthy are peptidomimetic and nonpeptide inhibitors of Src, Lck, Grb2, PI-3K, and Zap70 from pioneering efforts that led to the first examples of cellularly and in vivo active SH2 inhibitors. This mini-review highlights key achievements in SH2 inhibitor drug discovery with an emphasis on peptidomimetic and nonpeptide lead compounds in terms of structure-based design, key chemical and biological properties, and proof-of-concept studies relative to further defining the role(s) of SH2 domains in signal transduction processes, cellular functions, and in vivo disease models.

The exceptional chelating ability of dimethylaluminum chloride and methylaluminum dichloride. The merged stereochemical impact of alpha- and beta-stereocenters in chelate-controlled carbonyl addition reactions with enolsilane and hydride nucleophiles

A systematic investigation of the stereoselectivity in Lewis acid-promoted (Mukaiyama) aldol reactions of achiral unsubstituted enolsilanes and chiral beta-hydroxy aldehydes proceeding under conditions favoring chelation control is presented. Good stereocontrol can be realized for enolsilane aldol reactions of beta-alkoxy and beta-silyloxy aldehydes bearing only an alpha- or a beta-stereogenic center. Examination of the chelated intermediates for alpha,beta-disubstituted aldehydes concludes that the syn aldehyde diastereomer possesses the arrangement of stereocenters wherein the alpha- and beta-substituents impart a reinforcing facial bias upon the aldehyde carbonyl. Aldol reactions of syn aldehydes were thus observed to proceed with uniformly excellent diastereofacial selectivity. Aldol reactions of the corresponding anti aldehydes containing opposing stereocontrol elements at the alpha- and beta-positions exhibit variable and unpredictable selectivity.

A novel phosphotyrosine mimetic 4'-carboxymethyloxy-3'-phosphonophenylalanine (Cpp): exploitation in the design of nonpeptide inhibitors of pp60(Src) SH2 domain

The novel phosphotyrosine (pTyr) mimetic 4'-carboxymethyloxy-3'-phosphonophenylalanine (Cpp) has been designed and incorporated into a series of nonpeptide inhibitors of the SH2 domain of pp60(c-Src) (Src) tyrosine kinase. A 2.2 A X-ray crystal structure of 1a bound to a mutant form of Lck SH2 domain provides insight regarding the structure-activity relationships and supports the design concept of this new pTyr mimetic.

Synthesis and antitumor activity of spin labeled derivatives of podophyllotoxin

Three new nitroxyl labeled derivatives of podophyllotoxin 4-6 have been synthesized and evaluated for their antitumor activity in vitro. Compounds 4-6 showed significant inhibitory activity against human nasopharyngeal carcinoma KB,lung cancer A549 and stomach carcinoma SGC-7901 cells, as well as mouse leukemia L1210 and P388 cells. Compounds 4 and 5 exhibited comparable or superior activity to clinically used etoposide (VP-16,2) in their inhibition of these cell lines.

[Plasma endothelin level in patients with pregnancy induced hypertension and its correlation with atrial natriuretic peptide]

Plasma levels of endothelin (ET) and atrial natriuretic peptide (ANP) were measured in 32 normal pregnant women and 26 patients with pregnancy induced hypertension (PIH). The correlation between ET and ANP were examined. This study indicated that the levels of ET and ANP in hypertensive pregnancy were higher than those of the normal pregnancy (P < 0.01). There was no correlation between ET and ANP in normal pregnancy (r = 0.18, P > 0.05), but significant inverse correlation in the patient with PIH (r = -0.57, P < 0.05). There findings suggested that ET may play an important role in the pathogenesis of PIH. An imbalance of increased amount of ET relative to deficient ANP may lead to PIH.

[Clinical analysis of 36 repeat cesarean sections performed extraperitoneally]

Extraperitoneal repeat cesarean section (CS) performed in 36 women with previous intraperitoneal CS (group A) was compared with another 36 cases of intraperitoneal repeat CS (group B). The average blood loss was 146ml in group A and 230ml in group B (P < 0.01). Operation time in group A lasted 40 minutes including 9 cases of tubal ligation coincidentally and 66 minutes in B with 12 tubal ligation (P < 0.05). There were 2 cases of peritoneal damage and 1 transient hematuria in group A. Postoperative morbidity in group A was 16.7% and 38.9% in group B (P < 0.01). The average time for bowel function recurrence was 26.2 hours in A and 52.6 in B respectively. No evident complication occurred in either group. It indicated that extraperitoneal route might be superior to intraperitoneal one for repeat cesarean section.

[Motilin and gastrin in human milk]

The concentrations of motilin and gastrin were determined in the blood and milk of 45 women 3-5 days postpartum, and in the blood of 20 healthy non-pregnant women as control. Plasma motilin concentration (443.05 +/- 140.79 ng/L) and serum gastrin level (301.32 +/- 100.98 ng/L) were significantly higher in postpartum women than those in the control (366.12 +/- 96.23 ng/L and 76.13 +/- 13.11 ng/L, respectively) (P < 0.01). The concentrations of both motilin and gastrin in the milk were approximately one half of those in the blood and they were not present in the boiled milk. The results indicated that both hormones in the human milk may be important for development and maturation of gastro-intestinal function in neonates, especially for immature babies.

[Changes of plasma motilin concentration in pregnancy and early postpartum period]

Plasma motilin concentration were determined by radioimmunoaction from 180 women during pregnancy and early postpartum period as compared with 20 healthy non-pregnant women. The results showed that mean plasma motilin concentration (384.40 +/- 110.30 ng/L) was higher in the first trimester of pregnancy than that of healthy non-pregnant women (366.12 +/- 96.23 ng/L), however, this difference did not reach statistical significance (P > 0.05). The mean plasma motilin concentration (323.90 +/- 125.10 ng/L) was lower in the second trimester of pregnancy than in the first trimester of pregnancy (P < 0.05), while the mean plasma motilin concentration in the third trimester of pregnancy (121.04 +/- 27.00 ng/L) was significantly lower than in second (P < 0.01) and the mean plasma motilin concentration in 3-5 d after delivery (443.05 +/- 140.79 ng/L) reached an even higher value (P < 0.01). Our results suggests that pregnancy appears to have a profound inhibitory effect on plasma motilin and this may in part be responsible for the gastrointestinal hypomotility during pregnancy.

[The use of synthetic haANP III in the treatment of heart failure in pregnancy induced hypertension]

Highly active atrial natriuretic peptide III (haANP III) was administered for the treatment of heart failure due to pregnancy induced hypertension (PIH) in 7 patients with success. The heart failure was rapidly controlled within 24-48 hours with lowering of the blood pressure, disappearance of edema and urinary protein and alleviation of subjective symptoms. The plasma level of renin, angiotensin, aldosterone (RAA) and SOD all decreased. The results suggested that haANP III had the ability to facilitate the excretion of sodium and water, dilate the blood vessels and inhibit the action of RAA, and it could effectively reduce heart load and improve the cardiac function. Therefore, haANP III seemed to be an ideal new drug in treating heart failure in PIH, and it would have a wide scope for future development.

Curative effects of highly active atrial natriuretic peptide on severe pregnancy-induced hypertension

A new highly active atrial natriuretic peptide (haANP), synthesized by a solid phase technique, was given by intravenous infusion to 20 patients with severe pregnancy-induced hypertension (PIH) and the curative result of haANP was observed. Compared with basal values, supine systolic and diastolic BP was lowered significantly (P < 0.01), which may be related to the specific receptor of hANP and inhibition of renin-angiotensin-aldosterone system (RAAS). The haANP was found to possess significant effects of antispasm, detumescence and reducing proteinuria, probably by repairing mildly injured glomerulae, strong effects of diuresis and improving heart function with no side effects. Auto-antibody of hANP was found in patients with severe PIH, which affected the function of target cells of highly concentrated endogenous hANP. This auto-antibody might be one of the causes for PIH.

[Antigenic localities in the tissues of Metagonimus yokogawai in the period of growth]

In order to observe the antigenic localization in the tissues of Metagonimus yokogawai in growth stages, immunogoldlabeling method was applied to using serum of the cat which infected with isolated metacercariae from Plecoglossus altivelis. The sectioned worm tissues from each growth stages were embedded in Lowicryl HM 20 medium, stained with infected serum IgG and protein A gold complex (particle size: 12 nm) and observed by electron microscopy. In the worm tissues of all experimental groups, the gold particles were specifically concentrated on the tegumental syncytium and cytoplasm of the tegumental cell as well as the secretory granules in the parenchymal tissue. In the 16th and 20th week grown worm tissues, the gold particles were specifically concentrated on the vesicles in the tegumental syncytium and cytoplasm of the tegumental cell. The gold particles were specifically concentrated on the caecal epithelia of the 4th, 8th and 12th week growth groups but slightly concentrated on those of the 16th and 20th week.

Distribution and characteristics of placental ANP receptors in normal and hypertensive pregnancy

The ANP (atrial natriuretic peptide) receptor binding site was studied in human placentas of normal and hypertensive pregnancy. The results showed there were specific high affinity ANP receptors in the nonbrush border (fetal side), and their affinity to ANP was higher than that in the microvillous membrane (meternal side). The ANP receptor affinity in the nonbrush border and microvillous membrane of normal pregnancy was higher than that of hypertensive pregnancy. Though the weight of placentas of hypertensive pregnancy was lower than that of normal pregnancy, high ANP concentrations in the placental tissues, umbilical and maternal blood were found in hypertensive pregnancy. It is believed that the distribution of ANP receptors in the placentas is related to hemodynamics, maternal exchange and fluid and electrolyte balance. The decrease of ANP receptors and lowering of affinity in hypertensive pregnancy may influence the the target cell effect of ANP, especially in the fetal side. This may be related to the pathogenesis of hypertensive pregnancy.

Significance of changes in serum superoxide dismutase level in hypertensive syndrome of pregnancy

The concentration of human serum superoxide dismutase-1 (hSOD-1) containing copper and zinc ions were measured by radioimmunoassay healthy nonpregnant women, 15 normal pregnant women, 15 patients with mild to moderate hypertension (MMHSP) and 15 with severe hypertensive syndrome of pregnancy (SHSP). The mean serum hSOD-1 concentration in nonpregnant women was 148.84 +/- 60.53 (x +/- s) micrograms/L; while in the other 3 groups it was 394.19 +/- 122.21 micrograms/L, 377.12 +/- 173.45 micrograms/L and 581.15 +/- 118.50 micrograms/L. The results suggest that harmful free radicals increase gradually and a strong body defence system against oxidation damage of tissue cells is produced in the course of normal pregnancy and MMHSP. With cardionatrin treatment serum hSOD-1 concentrations of patients ameliorated returned to the level of normal pregnancy. The results indicate that there is a positive correlation between cardionatrin and hSOD-1 levels (r = 0.569, P less than 0.05), and a physiological regulation of the defence system exists, which may be related to the white blood cells. Hence, hSOD-1 probably plays a significant role in defence during normal pregnancy and hypertensive syndrome of pregnancy (HSP).

Oral contraceptives: effects on plasma insulin response to glucose and on the response to insulin and 2-deoxyglucose uptake by peripheral tissue

Oral contraceptive steroids, norethynodrel and mestranol, were fed to 11-wk-old female Sprague-Dawley rats, in combination and in quantities proportional to those used by women for contraceptive purposes. Three experiments were performed. The first experiment, demonstrated that 10 wk of treatment, impaired the animal's glucose tolerance, but not its insulin response to glucose. The second experiment demonstrated that 6 wk of steroid feeding, decreased the in vivo conversion of blood U-14C-labeled glucose into adipose tissue fatty acids and into diaphragm glycogen, although the effect on the diaphragm was not statistically significant. In the third experiment, it was found that the uptake of 2-deoxyglucose-1-14C by the adipose tissue removed from rats after 6 wk of treatment, was not different from that of control tissue, but the uptake by the hemidiaphragms was slightly lower.