Discovery of a new class of integrin antibodies for fibrosis.

Lung fibrosis, or the scarring of the lung, is a devastating disease with huge unmet medical need. There are limited treatment options and its prognosis is worse than most types of cancer. We previously discovered that MK-0429 is an equipotent pan-inhibitor of αv integrins that reduces proteinuria and kidney fibrosis in a preclinical model.

An integrin antagonist (MK-0429) decreases proteinuria and renal fibrosis in the ZSF1 rat diabetic nephropathy model.

Multiple integrins have been implicated in modulating renal function. Modulation of integrin function can lead to pathophysiological processes associated with diabetic nephropathy such as alterations in the glomerular filtration barrier and kidney fibrosis. The complexity of these pathophysiological changes implies that multiple integrin subtypes might need to be targeted to ameliorate the progression of renal disease.

Structural basis for selectivity and diversity in angiotensin II receptors.

The angiotensin II receptors ATR and ATR serve as key components of the renin-angiotensin-aldosterone system. ATR has a central role in the regulation of blood pressure, but the function of ATR is unclear and it has a variety of reported effects. To identify the mechanisms that underlie the differences in function and ligand selectivity between these receptors, here we report crystal structures of human ATR bound to an ATR-selective ligand and to an ATR/ATR dual ligand, capturing the receptor in an active-like conformation.

Discovery of novel non-steroidal reverse indole mineralocorticoid receptor antagonists.

Reported herein are a series of reverse indoles that represent novel non-steroidal mineralocorticoid receptor (MR) antagonists. The key structure-activity relationships (SAR) are presented below. This reverse indole series is exemplified by a compound that demonstrated efficacy in an acute natriuresis rodent model comparable to marketed MR antagonists, spironolactone and eplerenone.

Moderate to high throughput in vitro binding kinetics for drug discovery.

This review provides a concise summary for state of the art, moderate to high throughput in vitro technologies being employed to study drug-target binding kinetics. These technologies cover a wide kinetic timescale spanning up to nine orders of magnitude from milliseconds to days. Automated stopped flow measures transient and (pre)steady state kinetics from milliseconds to seconds.

Discovery and Pharmacology of a Novel Class of Diacylglycerol Acyltransferase 2 Inhibitors.

DGAT2 plays a critical role in hepatic triglyceride production, and data suggests that inhibition of DGAT2 could prove to be beneficial in treating a number of disease states. This article documents the discovery and optimization of a selective small molecule inhibitor of DGAT2 as well as pharmacological proof of biology in a mouse model of triglyceride production.

Identification of DGAT2 Inhibitors Using Mass Spectrometry.

Mass spectrometry offers significant advantages over other detection technologies in the areas of hit finding, hit validation, and medicinal chemistry compound optimization. The foremost obvious advantage is the ability to directly measure enzymatic product formation. In addition, the inherent sensitivity of the liquid chromatography/mass spectrometry (LC/MS) approach allows the execution of enzymatic assays at substrate concentrations typically at or below substrate Km.

Discovery of benzimidazole oxazolidinediones as novel and selective nonsteroidal mineralocorticoid receptor antagonists.

Elaboration of the oxazolidinedione series led to replacement of the exocyclic amides with substituted benzimidazoles. The structure-activity relationship (SAR) exploration resulted in the discovery of potent and selective nonsteroidal mineralocorticoid receptor (MR) antagonists with significantly improved microsomal stability and pharmacokinetic (PK) profile relative to the HTS hit 1a. One compound 2p possessed comparable efficacy as spironolactone (SPL) at 100 mg/kg (p.

Pyrazoles as non-classical bioisosteres in prolylcarboxypeptidase (PrCP) inhibitors.

Bioisosteres are integral components of modern pharmaceutical research that allow structural optimization to maximize in vivo efficacy and minimize adverse effects by selectively modifying pharmacodynamic, pharmacokinetic and physicochemical properties. A recent medicinal chemistry campaign focused on identifying small molecule inhibitors of prolylcarboxypeptidase (PrCP) initiated an investigation into the use of pyrazoles as bioisosteres for amides. The results indicate that pyrazoles are suitable bioisosteric replacements of amide functional groups.

Mineralocorticoid receptor antagonists: identification of heterocyclic amide replacements in the oxazolidinedione series.

Novel potent and selective mineralocorticoid receptor antagonists were identified, utilizing heterocyclic amide replacements in the oxazolidinedione series. Structure-activity relationship (SAR) efforts focused on improving lipophilic ligand efficiency (LLE) while maintaining nuclear hormone receptor selectivity and reasonable pharmacokinetic profiles.

Discovery and optimization of orally active cyclohexane-based prolylcarboxypeptidase (PrCP) inhibitors.

The synthesis, SAR, binding affinities and pharmacokinetic profiles are described for a series of cyclohexane-based prolylcarboxypeptidase (PrCP) inhibitors discovered by high throughput screening. Compounds show high levels of ex vivo target engagement in mouse plasma 20 h post oral dose.

Discovery of novel oxazolidinedione derivatives as potent and selective mineralocorticoid receptor antagonists.

Novel oxazolidinedione analogs were discovered as potent and selective mineralocorticoid receptor (MR) antagonists. Structure-activity relationship (SAR) studies were focused on improving the potency and microsomal stability. Selected compounds demonstrated excellent MR activity, reasonable nuclear hormone receptor selectivity, and acceptable rat pharmacokinetics.

Evaluation of selective inhibitors of 11β-HSD1 for the treatment of hypertension.

In an effort to understand the origin of blood-pressure lowering effects observed in recent clinical trials with 11β-HSD1 inhibitors, we examined a set of 11β-HSD1 inhibitors in a series of relevant in vitro and in vivo assays. Select 11β-HSD1 inhibitors reduced blood pressure in our preclinical models but most or all of the blood pressure lowering may be mediated by a 11β-HSD1 independent pathway.

Diacylglycerol acyltransferase-1 (DGAT1) inhibition perturbs postprandial gut hormone release.

Diacylglycerol acyltransferase-1 (DGAT1) is a potential therapeutic target for treatment of obesity and related metabolic diseases. However, the degree of DGAT1 inhibition required for metabolic benefits is unclear. Here we show that partial DGAT1 deficiency in mice suppressed postprandial triglyceridemia, led to elevations in glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) only following meals with very high lipid content, and did not protect from diet-induced obesity.

A new class of prolylcarboxypeptidase inhibitors, part 2: the aminocyclopentanes.

A series of potent inhibitors of prolylcarboxypeptidase (PrCP) was developed by modifying a lead structure that was discovered by high-throughput screening. The tert-butyl pyrrolidine was replaced by an aminocyclopentane to reduce the metabolic liabilities of the original lead. The compounds demonstrated sub-nanomolar in vitro IC(50) values, minimal activity shifts in pure plasma and improved pharmacokinetics.

A new class of prolylcarboxypeptidase inhibitors, part 1: discovery and evaluation.

A new structural class of potent prolylcarboxypeptidase (PrCP) inhibitors was discovered by high-throughput screening. The series possesses a tractable SAR profile with sub-nanomolar in vitro IC(50) values. Compared to prior inhibitors, the new series demonstrated minimal activity shifts in pure plasma and complete ex vivo plasma target engagement in mouse plasma at the 20 h post-dose time point (po).

Discovery of aminoheterocycles as potent and brain penetrant prolylcarboxypeptidase inhibitors.

Efforts were dedicated to develop potent and brain penetrant prolylcarboxypeptidase (PrCP) inhibitors by replacing the amide group of original leads 1 and 2 with heterocycles. Aminopyrimidines including compound 32a were identified to display good PrCP inhibitory activity (32a, IC(50)=43 nM) and impressive ability to penetrate brain in mice (brain/plasma ratio: 1.4).

Discovery of benzodihydroisofurans as novel, potent, bioavailable and brain-penetrant prolylcarboxypeptidase inhibitors.

A series of benzodihydroisofurans were discovered as novel, potent, bioavailable and brain-penetrant prolylcarboxypeptidase (PrCP) inhibitors. The structure-activity relationship (SAR) is focused on improving PrCP activity and metabolic stability, and reducing plasma protein binding. In the established diet-induced obese (eDIO) mouse model, compound ent-3a displayed target engagement both in plasma and in brain.

Discovery of a new class of potent prolylcarboxypeptidase inhibitors derived from alanine.

Efforts to modify the central proline portion of lead compound 4 lead to the discovery of novel prolylcarboxypeptidase (PrCP) inhibitors. Especially, replacement with alanine afforded compound 19 displaying more potent human and mouse PrCP inhibitory activity than 4 and an overall comparable profile.

The discovery of non-benzimidazole and brain-penetrant prolylcarboxypeptidase inhibitors.

Novel prolylcarboxypeptidase (PrCP) inhibitors with nanomolar IC(50) values were prepared by replacing the previously described dichlorobenzimidazole-substituted pyrrolidine amides with a variety of substituted benzylamine amides. In contrast to prior series, the compounds demonstrated minimal inhibition shift in whole serum and minimal recognition by P-glycoprotein (P-gp) efflux transporters. The compounds were also cell permeable and demonstrated in vivo brain exposure.

Concerted antigen processing of a short viral antigen by human caspase-5 and -10.

The generation of peptides presented by MHC class I molecules requires the proteolytic activity of the proteasome and/or other peptidases. The processing of a short vaccinia virus-encoded antigen can take place by a proteasome-independent pathway involving initiator caspase-5 and -10, which generate antigenic peptides recognized by CD8(+) T lymphocytes. In the present study, comparing single versus double enzyme digestions by mass spectrometry analysis, both qualitative and quantitative differences in the products obtained were identified.

Discovery of benzimidazole pyrrolidinyl amides as prolylcarboxypeptidase inhibitors.

A series of benzimidazole pyrrolidinyl amides containing a piperidinyl group were discovered as novel prolylcarboxypeptidase (PrCP) inhibitors. Low-nanomolar IC(50)'s were achieved for several analogs, of which compound 9b displayed modest ex vivo target engagement in eDIO mouse plasma. Compound 9b was also studied in vivo for its effect on weight loss and food intake in an eDIO mouse model and the results will be discussed.

Spiroimidazolidinone NPC1L1 inhibitors. Part 2: structure-activity studies and in vivo efficacy.

Ezetimibe (Zetia®), a cholesterol-absorption inhibitor (CAI) approved by the FDA for the treatment of hypercholesterolemia, is believed to target the intestine protein Niemann-Pick C1-Like 1 (NPC1L1) or its pathway. A spiroimidazolidinone NPC1L1 inhibitor identified by virtual screening showed moderate binding activity but was not efficacious in an in vivo rodent model of cholesterol absorption. Synthesis of analogs established the structure-activity relationships for binding activity, and resulted in compounds with in vivo efficacy, including 24, which inhibited plasma cholesterol absorption by 67% in the mouse, thereby providing proof-of-concept that non-β-lactams can be effective CAIs.

Design and synthesis of prolylcarboxypeptidase (PrCP) inhibitors to validate PrCP as a potential target for obesity.

Prolylcarboxypeptidase (PrCP) is a serine protease that may have a role in metabolism regulation. A class of reversible, potent, and selective PrCP inhibitors was developed starting from a mechanism based design for inhibiting this serine protease. Compound 8o inhibits human and mouse PrCP at IC(50) values of 1 and 2 nM and is not active (IC(50) > 25 μM) against a panel of closely related proteases.

Peptidomic profiling of human cerebrospinal fluid identifies YPRPIHPA as a novel substrate for prolylcarboxypeptidase.

Prolylcarboxypeptidase (PRCP) is a serine protease that catalyzes the cleavage of C-terminal amino acids linked to proline in peptides. It is ubiquitously expressed and is involved in regulating blood pressure, proliferation, inflammation, angiogenesis, and weight maintenance. To identify the candidate proximal target engagement markers for PRCP inhibition in the central nervous system, we profiled the peptidome of human cerebrospinal fluid to look for PRCP substrates using a MS-based in vitro substrate profiling assay.