Abdul Basit

Charles River Laboratories International, Inc · Discovery Bioanalysis (Large Molecule)

Rats are extensively used as a preclinical model for assessing drug pharmacokinetics (PK) and tissue distribution; however, successful translation of the rat data requires information on the differences in drug metabolism and transport mechanisms between rats and humans. To partly fill this knowledge gap, we quantified clinically relevant drug-meta...

Testosterone exhibits high variability in pharmacokinetics and glucuronidation after oral administration. While testosterone metabolism has been studied for decades, the impact of UGT2B17 gene deletion and the role of gut bacterial β-glucuronidases on its disposition are not well characterized. We first performed an exploratory study to investigate...

Dimethandrolone undecanoate (DMAU), an oral investigational male hormonal contraceptive is a prodrug, which is rapidly converted to its active metabolite, dimethandrolone (DMA). Poor and variable oral bioavailability of DMA after DMAU dosing is a critical challenge to develop it as an oral drug. The objective of our study was to elucidate the mecha...

A reliable translation of in vitro and preclinical data on drug absorption, distribution, metabolism, and excretion (ADME) to humans is important for safe and effective drug development. Precision medicine that is expected to provide the right clinical dose for the right patient at the right time requires a comprehensive understanding of population...

Dimethandrolone (DMA), an active metabolite of dimethandrolone undecanoate (DMAU) is a novel derivative of 19-nortestosterone that is undergoing clinical investigation as an experimental male hormonal contraceptive.1 However, poor and variable oral bioavailability of DMAU including dramatic food-effect2 may decrease its potential use by oral route....

The use of animal pharmacokinetic models as surrogates for humans relies on the assumption that the drug disposition mechanisms are similar between preclinical species and humans. However, significant cross-species differences exist in the tissue distribution and protein abundance of drug-metabolizing enzymes (DMEs) and transporters. We quantified...

Mitochondrial amidoxime-reducing component (mARC) enzymes are molybdenum-containing proteins that metabolize a number of endobiotics and xenobiotics. The interindividual variability and differential tissue abundance of mARC1 and mARC2 were quantified using targeted proteomics in three types of tissue fractions: 1) pediatric liver tissue homogenates...

[This corrects the article DOI: 10.3389/fimmu.2021.746503.].

Rheumatoid arthritis synovial fibroblasts (RASFs) contribute to synovial inflammation and bone destruction by producing a pleiotropic cytokine interleukin-6 (IL-6). However, the molecular mechanisms through which IL-6 propels RASFs to contribute to bone loss are not fully understood. In the present study, we investigated the effect of IL-6 and IL-6...

Interventions to decrease inflammation and improve metabolic function hold promise for the prevention of obesity-related diseases. Methylsulfonylmethane (MSM) is a naturally occurring compound that demonstrates antioxidant and anti-inflammatory effects. Improvements in measures of metabolic health have been observed in mouse models of obesity and d...

Anticancer drug, irinotecan shows serious dose-limiting gastrointestinal toxicity regardless of intravenous dosing. Although enzymes and transporters involved in irinotecan disposition are known, quantitative contributions of these mechanisms in complex in vivo disposition of irinotecan are poorly understood. We explained intestinal disposition and...

The increasing incidence of ocular diseases has accelerated research into therapeutic interventions needed for the eye. Ocular enzymes play important roles in the metabolism of drugs and endobiotics. Various ocular drugs are designed as prodrugs that are activated by ocular enzymes. Moreover, ocular enzymes have been implicated in the bioactivation...

Protein abundance data of drug-metabolizing enzymes and transporters (DMETs) are broadly applicable to the characterization of in vitro and in vivo models, in vitro to in vivo extrapolation (IVIVE), and interindividual variability prediction. However, the emerging need of DMET quantification in small sample volumes such as organ-on a chip effluent,...

Furosemide is a widely used diuretic for treating excessive fluid accumulation caused by disease conditions like heart failure and liver cirrhosis. Furosemide tablet formulation exhibits variable pharmacokinetics (PK) with bioavailability ranging from 10 to almost 100%. To explain the variable absorption, we integrated the physicochemical, in vitro...

The availability of assays that predict the contribution of cytochrome P450 (CYP) metabolism allows for the design of new chemical entities (NCEs) with minimal oxidative metabolism. These NCEs are often substrates of non-CYP drug metabolizing enzymes (DMEs), such as UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs), carboxylesterases (...

In Charcot–Marie–Tooth type 1A (CMT1A), Schwann cells exhibit a preponderant transcriptional deficiency of genes involved in lipid biosynthesis. This perturbed lipid metabolism affects the peripheral nerve physiology and the structure of peripheral myelin. Nevertheless, the identification and functional characterization of the lipid species mainly...

Interleukin-6 (IL-6) plays an important role in progressive bone loss in rheumatoid arthritis (RA). However, the molecular mechanisms through which IL-6 propels RA synovial fibroblasts (RASFs) to contribute to bone loss are not fully understood. Treatment of human RASFs with IL-6 and IL-6 receptor (IL-6/IL-6R, 100 ng/ml each) alone or in combinatio...

Current challenges in accurately predicting intestinal metabolism arise from the complex nature of the intestine, leading to limited applicability of available in vitro tools as well as knowledge deficits in intestinal physiology, including enzyme abundance. In particular, information on regional enzyme abundance along the small intestine is lackin...

Warfarin is a narrow therapeutic index anticoagulant drug and its use is associated with infrequent but significant adverse bleeding events. The international normalized ratio (INR) is the most commonly used biomarker to monitor and titrate warfarin therapy. However, INR is derived from a functional assay, which determines clotting efficiency at th...

UDP-glucuronosyltransferase 2B17 (UGT2B17) is a highly variable androgen- and drug-metabolizing enzyme. UGT2B17 exhibits a unique ontogeny profile characterized by a dramatic increase in hepatic protein expression from pre-pubertal age to adulthood. Age, sex, copy number variation (CNV), and single nucleotide polymorphisms only explain 26% of varia...

Applications of quantitative proteomics are rapidly emerging in the field of drug metabolism and pharmacokinetics. Here, we focus on the targeted MRM-based proteomics, which is widely utilized in quantifying drug metabolizing enzymes and transporters (DMET) proteins. The basic workflow is explained from proteotypic peptide selection, sample process...

Renal transporters, which are primarily located in the proximal tubules, play an important role in secretion and nephrotoxicity of drugs. The goal of this study was to characterize the age-dependent protein abundance of human renal transporters. A total of 43 human kidneys, 26 of which were paired with livers from the same donors, were obtained and...

Limited understanding of species differences in kidney transporters is a critical knowledge gap for prediction of drug-induced acute kidney injury, drug interaction, and pharmacokinetics in humans. Here, we report protein abundance data of nineteen transporters in the kidney cortex across five species (human, monkey, dog, rat, and mouse). In genera...

Introduction Current markers of Parkinson’s disease (PD) fail to detect the early progression of disease state. Conversely, current omics techniques allow the investigation of hundreds of molecules potentially altered by disease conditions. Based on evidence previously collected by our group in a mouse model of PD, we speculated that a particular s...

Testosterone glucuronide (TG), androsterone glucuronide (AG), etiocholanolone glucuronide (EtioG) and dihydrotestosterone glucuronide (DHTG) are the major metabolites of testosterone (T), which are excreted in urine and bile. Glucuronides can be deconjugated to active androgen in gut lumen after biliary excretion, which in turn can affect physiolog...

Circulating ceramide levels are abnormally elevated in age-dependent pathologies such as cardiovascular diseases, obesity and Alzheimer's disease. Nevertheless, the potential impact of age on plasma ceramide levels has not yet been systematically examined. In the present study, we quantified a focused panel of plasma ceramides and dihydroceramides...

Alzheimer’s disease (AD) is a slow-progressing disease of the brain characterized by symptoms such as impairment of memory and other cognitive functions. AD is associated with an inflammatory process that involves astrocytes and microglial cells, among other components. Astrocytes are the most abundant type of glial cells in the central nervous sys...

Protein abundance and activity of UGT2B17, a highly variable drug- and androgen-metabolizing enzyme, was quantified in microsomes, S9, and primary cells isolated from human liver and intestine by a validated LC-MS/MS methods. UGT2B17 protein abundance showed >160-fold variation (mean ± SD, 1.7 ± 2.7 pmol/mg microsomal protein) in adult human liver...

Circulating ceramide levels are abnormally elevated in age-dependent pathologies such as cardiovascular diseases, obesity and Alzheimer's disease. Nevertheless, the potential impact of age on plasma ceramide levels has not yet been systematically examined. In the present study, we quantified a focused panel of plasma ceramides and dihydroceramides...

Development of an oral testosterone (T) therapy has proven extremely challenging because of extensive and variable first‐pass metabolism. We investigated the in vivo metabolism of T with increasing oral doses of T, both alone and with the co‐administration of dutasteride (5α‐reductase inhibitor) by LC‐MS/MS. In eugonadal men prior to dosing, the ci...

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

The ontogeny of hepatic uridine diphosphate‐glucuronosyltransferases (UGTs) was investigated by LC‐MS/MS proteomics to determine UGT protein abundance in human liver microsomes isolated from 136 pediatric (0‐18 years) and 35 adult (age 18‐67 years) donors. Microsomal protein abundances of UGT1A1, UGT1A4, UGT1A6, UGT1A9, UGT2B7 and UGT2B15 increased...

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

BACKGROUND Inhibition of UGT1A1 by kinase inhibitors (KIs) has been shown to cause mild to serve hyperbilirubinemia in cancer patients1. UGT1A1 is highly polymorphic and displays variable expression. The specific aims of this study were i) to stratify human liver microsomes (HLMs) based on UGT1A1 abundance, activity and genotype, ii) to screen 10...

The major objective of this study was to investigate association of genetic and non-genetic factors with variability in protein abundance and in vitro activity of the androgen metabolizing enzyme, UGT2B17, in human liver microsomes (n=455). UGT2B17 abundance was quantified by LC-MS/MS proteomics and enzyme activity was determined by using testoster...

Alterations of lipid metabolism have been frequently associated with Huntington's disease (HD) over the past years. HD is the most common neurodegenerative disorder, with a complex pathogenic profile, typically characterized by progressive striatal and cortical degeneration and associated motor, cognitive and behavioral disturbances. Previous findi...

Our understanding of the physiological and pathological functions of brain lipids is limited by the inability to analyze these molecules at cellular resolution. Here, we present a method that enables the detection of lipids in identified single neurons from live mammalian brains. Neuronal cell bodies are captured from perfused mouse brain slices by...

Huntington’s disease is characterized by a complex and heterogeneous pathogenic profile. Studies have shown that disturbance in lipid homeostasis may represent a critical determinant in the progression of several neurodegenerative disorders. The recognition of perturbed lipid metabolism is only recently becoming evident in HD. In order to provide m...

Fast, accurate and reliable methods to quantify the amount of myelin still lack, both in humans and experimental models. The overall objective of the present study was to demonstrate that sphingomyelin (SM) in the cerebrospinal fluid (CSF) of patients affected by demyelinating neuropathies is a myelin biomarker. We found that SM levels mirror both...

Sphingolipids have been implicated in age-related neurodegeneration. Previous studies have reported elevated ceramide levels in the brain of old rodents, but a systematic investigation of the impact of age on brain sphingolipid metabolism is still lacking. Here we quantified 17 key sphingolipid species in the hippocampus of young (3months), middle-...

Huntington's disease is characterized by a complex and heterogeneous pathogenic profile. Studies have shown that disturbance in lipid homeostasis may represent a critical determinant in the progression of several neurodegenerative disorders. The recognition of perturbed lipid metabolism is only recently becoming evident in HD. In order to provide m...

Red beetroot (RB) powder was incorporated into starch-based bio-elastomers to obtain flexible biocomposites with tunable antioxidant properties. Starch granules within the bio-elastomers affected the release of the antioxidant molecule betanin in the RB powder. The bio-elastomers were hydrophobic and resisted dissolution in water, hence the release...

Background Among all the complex mechanisms underlying the pathogenesis of Huntington’s disease (HD), perturbation of brain lipids has been hypothesised to play a relevant role. Sphingosine-1-phosphate (S1P), a potent signalling sphingolipid that regulates a number of processes essential for cellular homeostasis, differentiation, motility and cell...

We describe a simple method for the detection of low intensity lipid signals in complex tissue samples, based on a combination of liquid chromatography/mass spectrometry and ion mobility mass spectrometry. The method relies on visual and software-assisted analysis of overlapped mobilograms (diagrams of mass-to-charge ratio, m/z, vs drift time, DT)...

Acid ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine-1-phosphate (S1P). In the present study, we evaluated the role of AC-regulated sphingolipid signaling in melanoma. We found that AC...

The second messenger hydrogen peroxide transduces changes in the cellular redox state by reversibly oxidizing protein cysteine residues to sulfenic acid. This signaling event regulates many cellular processes but has never been shown to occur in the brain. Here, we report that hydrogen peroxide heightens endocannabinoid signaling in brain neurons t...