Publications by authors named "Brahma Ghosh"

10 Publications

  • Page 1 of 1

Discovery of a novel series of guanidinebenzoates as gut-restricted enteropeptidase and trypsin dual inhibitors for the treatment of metabolic syndrome.

Bioorg Med Chem Lett 2021 May 11;40:127939. Epub 2021 Mar 11.

Discovery Chemistry, Janssen Research and Development, LLC, Spring House, PA, United States.

A novel series of guanidinebenzoate enteropeptidase and trypsin dual inhibitors has been discovered and SAR studies were conducted. Optimization was focused on improving properties for gut restriction, including increased aqueous solubility, lower cellular permeability, and reduced oral bioavailability. Lead compounds were identified with efficacy in a mouse fecal protein excretion study.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmcl.2021.127939DOI Listing
May 2021

Pharmacologic Characterization of JNJ-42226314, [1-(4-Fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone, a Reversible, Selective, and Potent Monoacylglycerol Lipase Inhibitor.

J Pharmacol Exp Ther 2020 03 9;372(3):339-353. Epub 2019 Dec 9.

Janssen Research & Development, LLC, San Diego, California.

The serine hydrolase monoacylglycerol lipase (MAGL) is the rate-limiting enzyme responsible for the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) into arachidonic acid and glycerol. Inhibition of 2-AG degradation leads to elevation of 2-AG, the most abundant endogenous agonist of the cannabinoid receptors (CBs) CB1 and CB2. Activation of these receptors has demonstrated beneficial effects on mood, appetite, pain, and inflammation. Therefore, MAGL inhibitors have the potential to produce therapeutic effects in a vast array of complex human diseases. The present report describes the pharmacologic characterization of [1-(4-fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone (JNJ-42226314), a reversible and highly selective MAGL inhibitor. JNJ-42226314 inhibits MAGL in a competitive mode with respect to the 2-AG substrate. In rodent brain, the compound time- and dose-dependently bound to MAGL, indirectly led to CB1 occupancy by raising 2-AG levels, and raised norepinephrine levels in cortex. In vivo, the compound exhibited antinociceptive efficacy in both the rat complete Freund's adjuvant-induced radiant heat hypersensitivity and chronic constriction injury-induced cold hypersensitivity models of inflammatory and neuropathic pain, respectively. Though 30 mg/kg induced hippocampal synaptic depression, altered sleep onset, and decreased electroencephalogram gamma power, 3 mg/kg still provided approximately 80% enzyme occupancy, significantly increased 2-AG and norepinephrine levels, and produced neuropathic antinociception without synaptic depression or decreased gamma power. Thus, it is anticipated that the profile exhibited by this compound will allow for precise modulation of 2-AG levels in vivo, supporting potential therapeutic application in several central nervous system disorders. SIGNIFICANCE STATEMENT: Potentiation of endocannabinoid signaling activity via inhibition of the serine hydrolase monoacylglycerol lipase (MAGL) is an appealing strategy in the development of treatments for several disorders, including ones related to mood, pain, and inflammation. [1-(4-Fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone is presented in this report to be a novel, potent, selective, and reversible noncovalent MAGL inhibitor that demonstrates dose-dependent enhancement of the major endocannabinoid 2-arachidonoylglycerol as well as efficacy in models of neuropathic and inflammatory pain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.119.262139DOI Listing
March 2020

Understanding Lung Deposition of Alpha-1 Antitrypsin in Acute Experimental Mouse Lung Injury Model Using Fluorescence Microscopy.

Int J Mol Imaging 2016 6;2016:5768312. Epub 2016 Dec 6.

Pharmacokinetics, Dynamics and Metabolism, Pfizer Inc., Andover, MA, USA.

Human plasma-derived 1-antitrypsin (AAT) delivered by intravenous infusion is used as augmentation therapy in patients with emphysema who have a genetic mutation resulting in deficiency of AAT. Inhalation is an alternative route of administration that can potentially increase the efficacy and convenience of treatment. This study was conducted to determine whether delivery to the lungs, initially via the intratracheal (IT) route of administration, would deliver efficacious levels of a recombinant AAT (rAAT) to the site of action in the lungs in mice. I-radiolabeled rAAT, fluorophore-conjugated rAAT (rAAT-Alexa488), and NE680 (neutrophil elastase 680, a silent fluorescent substrate of neutrophil elastase which fluoresces in the near-infrared range upon activation by neutrophil elastase) were used to characterize the pharmacokinetics and tissue distribution profile, distribution of rAAT within the lung, and efficacy of rAAT to inhibit neutrophil elastase at the site of action, respectively. The study has demonstrated that rAAT was able to gain access to locations where neutrophil elastase was localized. The histochemical quantification of rAAT activity relative to dose at the site of action provided here will improve confidence in predicting the human dose via the inhalation route.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2016/5768312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5168502PMC
December 2016

Synthesis and evaluation of potential inhibitors of human and Escherichia coli histidine triad nucleotide binding proteins.

Bioorg Med Chem Lett 2012 Jan 31;22(1):558-60. Epub 2011 Oct 31.

Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA.

Based on recent substrate specificity studies, a series of ribonucleotide based esters and carbamates were synthesized and screened as inhibitors of the phosphoramidases and acyl-AMP hydrolases, Escherichia coli Histidine Triad Nucleotide Binding Protein (ecHinT) and human Histidine Triad Nucleotide Binding Protein 1 (hHint1). Using our established phosphoramidase assay, K(i) values were determined. All compounds exhibited non-competitive inhibition profiles. The carbamate based inhibitors were shown to successfully suppress the Hint1-associated phenotype in E. coli, suggesting that they are permeable intracellular inhibitors of ecHinT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmcl.2011.10.082DOI Listing
January 2012

E. coli histidine triad nucleotide binding protein 1 (ecHinT) is a catalytic regulator of D-alanine dehydrogenase (DadA) activity in vivo.

PLoS One 2011 6;6(7):e20897. Epub 2011 Jul 6.

Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America.

Histidine triad nucleotide binding proteins (Hints) are highly conserved members of the histidine triad (HIT) protein superfamily. Hints comprise the most ancient branch of this superfamily and can be found in Archaea, Bacteria, and Eukaryota. Prokaryotic genomes, including a wide diversity of both gram-negative and gram-positive bacteria, typically have one Hint gene encoded by hinT (ycfF in E. coli). Despite their ubiquity, the foundational reason for the wide-spread conservation of Hints across all kingdoms of life remains a mystery. In this study, we used a combination of phenotypic screening and complementation analyses with wild-type and hinT knock-out Escherichia coli strains to show that catalytically active ecHinT is required in E. coli for growth on D-alanine as a sole carbon source. We demonstrate that the expression of catalytically active ecHinT is essential for the activity of the enzyme D-alanine dehydrogenase (DadA) (equivalent to D-amino acid oxidase in eukaryotes), a necessary component of the D-alanine catabolic pathway. Site-directed mutagenesis studies revealed that catalytically active C-terminal mutants of ecHinT are unable to activate DadA activity. In addition, we have designed and synthesized the first cell-permeable inhibitor of ecHinT and demonstrated that the wild-type E. coli treated with the inhibitor exhibited the same phenotype observed for the hinT knock-out strain. These results reveal that the catalytic activity and structure of ecHinT is essential for DadA function and therefore alanine metabolism in E. coli. Moreover, they provide the first biochemical evidence linking the catalytic activity of this ubiquitous protein to the biological function of Hints in Escherichia coli.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020897PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3130732PMC
November 2011

Bilitrienones from the chemical oxidation of dodecasubstituted porphyrins.

Tetrahedron 2010 Jan;66(1):63-67

Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.

The structure of the ring-opened product from direct oxidation of meso-tetraarylporphyrins has been controversial for three decades. Herein we show that bilitrienones 2 are obtained from oxidation of metal-free dodecasubstituted porphyrins 1 in the presence of sodium nitrite, trifluoroacetic acid and air oxygen. The presence of the para-nonyl groups in 1b stabilized the corresponding bilitrienone 2b, which was characterized by X-ray crystallography. In the absence of the para-nonyl groups bilitrienone 2a undergoes a rapid hydration reaction, giving biladienone 3a as the major isolated product. The molecular structures of 2b and 3a, and. the photochemical isomerization of 3a are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tet.2009.10.098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904984PMC
January 2010

Identification of the amino acid-AZT-phosphoramidase by affinity T7 phage display selection.

Bioorg Med Chem Lett 2009 Nov 22;19(22):6379-81. Epub 2009 Sep 22.

Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA.

A CEM cell cDNA T7 phage display library was prepared and used to screen for activating enzymes of phosphoramidate prodrugs of AZT monophosphate. Although, inefficient compared to ribonucleotide based phosphoramidates, hHint 1 was identified as the likely intracellular pronucleotide activating enzyme.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmcl.2009.09.067DOI Listing
November 2009

Nontoxic chemical interdiction of the epithelial-to-mesenchymal transition by targeting cap-dependent translation.

ACS Chem Biol 2009 May;4(5):367-77

Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.

Normal growth and development depends upon high fidelity regulation of cap-dependent translation initiation, a process that is usurped and redirected in cancer to mediate acquisition of malignant properties. The epithelial-to-mesenchymal transition (EMT) is a key translationally regulated step in the development of epithelial cancers and pathological tissue fibrosis. To date, no compounds targeting EMT have been developed. Here we report the synthesis of a novel class of histidine triad nucleotide binding protein (HINT)-dependent pronucleotides that interdict EMT by negatively regulating the association of eIF4E with the mRNA cap. Compound eIF4E inhibitor-1 potently inhibited cap-dependent translation in a dose-dependent manner in zebrafish embryos without causing developmental abnormalities and prevented eIF4E from triggering EMT in zebrafish ectoderm explants without toxicity. Metabolism studies with whole cell lysates demonstrated that the prodrug was rapidly converted into 7-BnGMP. Thus we have successfully developed the first nontoxic small molecule able to inhibit EMT, a key process in the development of epithelial cancer and tissue fibrosis, by targeting the interaction of eIF4E with the mRNA cap and demonstrated the tractability of zebrafish as a model organism for studying agents that modulate EMT. Our work provides strong motivation for the continued development of compounds designed to normalize cap-dependent translation as novel chemo-preventive agents and therapeutics for cancer and fibrosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/cb9000475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2796976PMC
May 2009

Engineered monomeric human histidine triad nucleotide-binding protein 1 hydrolyzes fluorogenic acyl-adenylate and lysyl-tRNA synthetase-generated lysyl-adenylate.

J Biol Chem 2007 May 2;282(20):15137-47. Epub 2007 Mar 2.

Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.

Hint1 is a homodimeric protein and member of the ubiquitous HIT superfamily. Hint1 catalyzes the hydrolysis of purine phosphoramidates and lysyl-adenylate generated by lysyl-tRNA synthetase (LysRS). To determine the importance of homodimerization on the biological and catalytic activity of Hint1, the dimer interface of human Hint1 (hHint1) was destabilized by replacement of Val(97) of hHint1 with Asp, Glu, or Arg. The mutants were shown to exist as monomers in solution by a combination of size exclusion chromatograph, static light scattering, and chemically induced dimerization studies. Circular dichroism studies revealed little difference between the stability of the V97D, V97E, and wild-type hHint1. Relative to wild-type and the V97E mutant, however, significant perturbation of the V97D mutant structure was observed. hHint1 was shown to prefer 3-indolepropionic acyl-adenylate (AIPA) over tryptamine adenosine phosphoramidate monoester (TpAd). Wild-type hHint1 was found to be 277- and 1000-fold more efficient (k(cat)/K(m) values) than the V97E and V97D mutants, respectively. Adenylation of wild-type, V97D, and V97E hHint1 by human LysRS was shown to correlate with the mutant k(cat)/K(m) values using 3-indolepropionic acyl-adenylate as a substrate, but not tryptamine adenosine phosphoramidate monoester. Significant perturbations of the active site residues were not detected by molecular dynamics simulations of the hHint1s. Taken together, these results demonstrate that for hHint1; 1) the efficiency (k(cat)/K(m)) of acylated AMP hydrolysis, but not maximal catalytic turnover (k(cat)), is dependent on homodimerization and 2) the hydrolysis of lysyl-AMP generated by LysRS is not dependent on homodimerization if the monomer structure is similar to the wild-type structure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M606972200DOI Listing
May 2007

Phosphoramidate pronucleotides: a comparison of the phosphoramidase substrate specificity of human and Escherichia coli histidine triad nucleotide binding proteins.

Mol Pharm 2007 Mar-Apr;4(2):208-17. Epub 2007 Jan 12.

Department of Medicinal Chemistry and Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.

To facilitate the delivery of nucleotide-based therapeutics to cells and tissues, a variety of pronucleotide approaches have been developed. Our laboratory and others have demonstrated that nucleoside phosphoramidates can be activated intracellularly to the corresponding 5'-monophosphate nucleotide and that histidine triad nucleotide binding proteins (Hints) are potentially responsible for their bioactivation. Hints are conserved and ubiquitous enzymes that hydrolyze phosphoramidate bonds between nucleoside 5'-monophosphate and an amine leaving group. On the basis of the ability of nucleosides to quench the fluorescence of covalently linked amines containing indole, a sensitive, continuous fluorescence-based assay was developed. A series of substrates linking the naturally fluorogenic indole derivatives to nucleoside 5'-monophosphates were synthesized, and their steady state kinetic parameters of hydrolysis by human Hint1 and Escherichia coli hinT were evaluated. To characterize the elemental and stereochemical effect on the reaction, two P-diastereoisomers of adenosine or guanosine phosphoramidothioates were synthesized and studied to reveal a 15-200-fold decrease in the specificity constant (kcat/Km) when the phosphoryl oxygen is replaced with sulfur. While a stereochemical preference was not observed for E. coli hinT, hHint1 exhibited a 300-fold preference for d-tryptophan phosphoramidates over l-isomers. The most efficient substrates evaluated to date are those that contain the less sterically hindering amine leaving group, tryptamine, with kcat and Km values comparable to those found for adenosine kinase. The apparent second-order rate constants (kcat/Km) for adenosine tryptamine phosphoramidate monoester were found to be 107 M-1 s-1 for hHint1 and 106 M-1 s-1 for E. coli hinT. Both the human and E. coli enzymes preferred purine over pyrimidine analogues. Consistent with observed hydrogen bonding between the 2'-OH group of adenosine monophosphate and the active site residue, Asp43, the second-order rate constant (kcat/Km) for thymidine tryptamine phosphoramidate was found to be 3-4 orders of magnitude smaller than that for uridine tryptamine phosphoramidate for hHint1 and 2 orders of magnitude smaller than that for E. coli hinT. Ara-A tryptamine phosphoramidate was, however, shown to be a good substrate with a specificity constant (kcat/Km) only 10-fold lower than the value for adenosine tryptamine phosphoramidate. Consequently, nucleoside phosphoramidates containing unhindered primary amines and either an alpha or beta 2'-OH group should be easily bioactivated by Hints with efficiencies rivaling those for the 5'-monophosphorylation of nucleosides by nucleoside kinases. The differential substrate specificity observed for human and E. coli enzymes represents a potential therapeutic rationale for the development of selective antibiotic phosphoramidate pronucleotides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/mp060070yDOI Listing
June 2007