10 research outputs found
Statistical Total Correlation Spectroscopy Scaling for Enhancement of Metabolic Information Recovery in Biological NMR Spectra
The high level of complexity in nuclear magnetic resonance
(NMR)
metabolic spectroscopic data sets has fueled the development of experimental
and mathematical techniques that enhance latent biomarker recovery
and improve model interpretability. We previously showed that statistical
total correlation spectroscopy (STOCSY) can be used to <i>edit</i> NMR spectra to remove drug metabolite signatures that obscure metabolic
variation of diagnostic interest. Here, we extend this âSTOCSY
editingâ concept to a generalized scaling procedure for NMR
data that enhances recovery of latent biochemical information and
improves biological classification and interpretation. We call this
new procedure STOCSY-scaling (STOCSY<sup>S</sup>). STOCSY<sup>S</sup> exploits the fixed proportionality in a set of NMR spectra between
resonances from the same molecule to suppress or enhance features
correlated with a resonance of interest. We demonstrate this new approach
using two exemplar data sets: (a) a streptozotocin rat model (<i>n</i> = 30) of type 1 diabetes and (b) a human epidemiological
study utilizing plasma NMR spectra of patients with metabolic syndrome
(<i>n</i> = 67). In both cases significant biomarker discovery
improvement was observed by using STOCSY<sup>S</sup>: the approach
successfully suppressed interfering NMR signals from glucose and lactate
that otherwise dominate the variation in the streptozotocin study,
which then allowed recovery of biomarkers such as glycine, which were
otherwise obscured. In the metabolic syndrome study, we used STOCSY<sup>S</sup> to enhance variation from the high-density lipoprotein cholesterol
peak, improving the prediction of individuals with metabolic syndrome
from controls in orthogonal projections to latent structures discriminant
analysis models and facilitating the biological interpretation of
the results. Thus, STOCSY<sup>S</sup> is a versatile technique that
is applicable in any situation in which variation, either biological
or otherwise, dominates a data set at the expense of more interesting
or important features. This approach is generally appropriate for
many types of NMR-based complex mixture analyses and hence for wider
applications in bioanalytical science
Comparative NMR-Based Metabonomic Investigation of the Metabolic Phenotype Associated with Tienilic Acid and Tienilic Acid Isomer
An NMR-based metabonomic approach was applied to study
the systems
level metabolic effects of two closely related thiophene compounds,
tienilic acid (TA) and tienilic acid isomer (TAI). The metabonomic
data were anchored with traditional clinical chemistry and histopathologic
analyses. TA was removed from the market as a result of suspected
immune-mediated hepatotoxicity, whereas TAI is an intrinsic hepatotoxin.
Equimolar doses of TA and TAI were administered to SpragueâDawley
rats, and sampling was conducted at 2, 6, and 24 h post-treatment.
Histopathologic analyses revealed development of a significant hepatic
lesion 24 h post-TAI treatment with a parallel increase in plasma
alanine aminotransferase (ALT) activity. In contrast, TA was not associated
with the development of a hepatic lesion or an increase in plasma
ALT activity. High-resolution NMR spectral metabolic profiles were
generated for liver extracts, plasma, and urine at multiple time points.
Multivariate statistical tools were applied to model the metabolic
profiles and identify discriminatory metabolites that reflected both
the adaptation to TA administration and the onset and progression
of TAI-induced hepatotoxicity. TAI was shown to induce marked metabolic
effects on the metabolome at all time points, with dramatic metabolic
perturbations at 24 h post-treatment correlating with the histopathologic
and clinical chemistry evidence of a hepatic lesion. The TAI-induced
metabolic perturbations provided evidence for the generation of electrophilic
reactive metabolites and a significant impairment of bioenergetic
metabolic pathways. TA induced early metabolic perturbations that
were largely resolved by 24 h post-treatment, suggesting the reestablishment
of metabolic homeostasis and the ability to adapt to the intervention,
with hepatic hypotaurine potentially representing a means of assessment
of hepatic adaptation. This comparative metabonomic approach enabled
the discrimination of metabolic perturbations that were common to
both treatments and were interpreted as nontoxic thiophene-induced
perturbations. Importantly, this approach enabled the identification
of temporal metabolic perturbations that were unique to TAI or TA
treatment and hence were of relevance to the development of toxicity
or the ability to adapt. This approach is applicable to the future
study of pharmacologically and structurally similar compounds and
represents a refined means of identification of biomarkers of toxicity
Pharmacometabonomic Characterization of Xenobiotic and Endogenous Metabolic Phenotypes That Account for Inter-individual Variation in Isoniazid-Induced Toxicological Response
An NMR-based pharmacometabonomic approach was applied
to investigate
inter-animal variation in response to isoniazid (INH; 200 and 400
mg/kg) in male SpragueâDawley rats, alongside complementary
clinical chemistry and histopathological analysis. Marked inter-animal
variability in central nervous system (CNS) toxicity was identified
following administration of a high dose of INH, which enabled characterization
of CNS responders and CNS non-responders. High-resolution post-dose
urinary <sup>1</sup>H NMR spectra were modeled both by their xenobiotic
and endogenous metabolic information sets, enabling simultaneous identification
of the differential metabolic fate of INH and its associated endogenous
metabolic consequences in CNS responders and CNS non-responders. A
characteristic xenobiotic metabolic profile was observed for CNS responders,
which revealed higher urinary levels of pyruvate isonicotinylhydrazone
and β-glucosyl isonicotinylhydrazide and lower levels of acetylisoniazid
compared to CNS non-responders. This suggested that the capacity for
acetylation of INH was lower in CNS responders, leading to increased
metabolism <i>via</i> conjugation with pyruvate and glucose.
In addition, the endogenous metabolic profile of CNS responders revealed
higher urinary levels of lactate and glucose, in comparison to CNS
non-responders. Pharmacometabonomic analysis of the pre-dose <sup>1</sup>H NMR urinary spectra identified a metabolic signature that
correlated with the development of INH-induced adverse CNS effects
and may represent a means of predicting adverse events and acetylation
capacity when challenged with high dose INH. Given the widespread
use of INH for the treatment of tuberculosis, this pharmacometabonomic
screening approach may have translational potential for patient stratification
to minimize adverse events
Additional file 2: Table S1. of Maternal urinary metabolic signatures of fetal growth and associated clinical and environmental factors in the INMA study
List of metabolite integrals and assignments obtained from NMR urine spectra. Abbreviations: UA, unassigned. *The method of multiple spike-in of authentic standards in the original sample allowed to validate the identity of NMR signals. The identity of P3G was confirmed by chromatographic isolation of the target feature (SI Methods) and comparison of MS/MS spectra to an authentic reference compound in accordance with reported guidelines for metabolite identification (Sumner et al. 2014). **Citation for STORM: Subset Optimization by Reference Matching (STORM): An Optimized Statistical Approach for Recovery of Metabolic Biomarker Structural Information from 1H NMR Spectra of Biofluids. Joram M. Posma, Isabel Garcia-Perez, Maria De Iorio, John C. Lindon, Paul Elliott, Elaine Holmes, Timothy M. D. Ebbels, and Jeremy K. Nicholson. Analytical Chemistry 2012 84 (24), 10694-10701 DOI: 10.1021/ac302360v. (DOCX 43 kb
Additional file 1: of Maternal urinary metabolic signatures of fetal growth and associated clinical and environmental factors in the INMA study
Supplementary methods. (DOCX 38 kb
Additional file 6: Figure S4. of Maternal urinary metabolic signatures of fetal growth and associated clinical and environmental factors in the INMA study
Heatmap of metabolite inter-correlation in urinary 1H NMR spectral profiles from Sabadell at week 34 of gestation (metabolite order created using the complete linkage method for hierarchical clustering). (PDF 48 kb
Pharmacometabonomic Investigation of Dynamic Metabolic Phenotypes Associated with Variability in Response to Galactosamine Hepatotoxicity
Galactosamine (galN) is widely used as an <i>in
vivo</i> model of acute liver injury. We have applied an integrative
approach,
combining histopathology, clinical chemistry, cytokine analysis, and
nuclear magnetic resonance (NMR) spectroscopic metabolic profiling
of biofluids and tissues, to study variability in response to galactosamine
following successive dosing. On re-challenge with galN, primary non-responders
displayed galN-induced hepatotoxicity (induced response), whereas
primary responders exhibited a less marked response (adaptive response).
A systems-level metabonomic approach enabled simultaneous characterization
of the xenobiotic and endogenous metabolic perturbations associated
with the different response phenotypes. Elevated serum cytokines were
identified and correlated with hepatic metabolic profiles to further
investigate the inflammatory response to galN. The presence of urinary <i>N</i>-acetylglucosamine (glcNAc) correlated with toxicological
outcome and reflected the dynamic shift from a resistant to a sensitive
phenotype (induced response). In addition, the urinary level of glcNAc
and hepatic level of UDP-<i>N</i>-acetylhexosamines reflected
an adaptive response to galN. The unique observation of galN-pyrazines
and altered gut microbial metabolites in fecal profiles of non-responders
suggested that gut microfloral metabolism was associated with toxic
outcome. Pharmacometabonomic modeling of predose urinary and fecal
NMR spectroscopic profiles revealed a diverse panel of metabolites
that classified the dynamic shift between a resistant and sensitive
phenotype. This integrative pharmacometabonomic approach has been
demonstrated for a model toxin; however, it is equally applicable
to xenobiotic interventions that are associated with wide variation
in efficacy or toxicity and, in particular, for prediction of susceptibility
to toxicity
High-Speed Quantitative UPLC-MS Analysis of Multiple Amines in Human Plasma and Serum via Precolumn Derivatization with 6âAminoquinolylâ<i>N</i>âhydroxysuccinimidyl Carbamate: Application to Acetaminophen-Induced Liver Failure
A targeted reversed-phase gradient
UPLC-MS/MS assay has been developed
for the quantification /monitoring of 66 amino acids and amino-containing
compounds in human plasma and serum using precolumn derivatization
with 6-aminoquinolyl-<i>N</i>-hydroxysuccinimidyl carbamate
(AccQTag Ultra). Derivatization of the target amines required minimal
sample preparation and resulted in analytes with excellent chromatographic
and mass spectrometric detection properties. The resulting method,
which requires only 10 ÎźL of sample, provides the reproducible
and robust separation of 66 analytes in 7.5 min, including baseline
resolution of isomers such as leucine and isoleucine. The assay has
been validated for the quantification of 33 amino compounds (predominantly
amino acids) over a concentration range from 2 to 20 and 800 ÎźM.
Intra- and interday accuracy of between 0.05 and 15.6 and 0.78â13.7%
and precision between 0.91 and 16.9% and 2.12â15.9% were obtained.
A further 33 biogenic amines can be monitored in samples for relative
changes in concentration rather than quantification. Application of
the assay to samples derived from healthy controls and patients suffering
from acetaminophen (APAP, paracetamol)-induced acute liver failure
(ALF) showed significant differences in the amounts of aromatic and
branched chain amino acids between the groups as well as a number
of other analytes, including the novel observation of increased concentrations
of sarcosine in ALF patients. The properties of the developed assay,
including short analysis time, make it suitable for high-throughput
targeted UPLC-ESI-MS/MS metabonomic analysis in clinical and epidemiological
environments
Development of a Series of Pyrrolopyridone MAT2A Inhibitors
The
optimization of an allosteric fragment, discovered by differential
scanning fluorimetry, to an in vivo MAT2a tool inhibitor is discussed.
The structure-based drug discovery approach, aided by relative binding
free energy calculations, resulted in AZâ9567 (21), a potent inhibitor in vitro with excellent preclinical pharmacokinetic
properties. This tool showed a selective antiproliferative effect
on methylthioadenosine phosphorylase (MTAP) KO cells, both in vitro
and in vivo, providing further evidence to support the utility of
MAT2a inhibitors as potential anticancer therapies for MTAP-deficient
tumors
Development of a Series of Pyrrolopyridone MAT2A Inhibitors
The
optimization of an allosteric fragment, discovered by differential
scanning fluorimetry, to an in vivo MAT2a tool inhibitor is discussed.
The structure-based drug discovery approach, aided by relative binding
free energy calculations, resulted in AZâ9567 (21), a potent inhibitor in vitro with excellent preclinical pharmacokinetic
properties. This tool showed a selective antiproliferative effect
on methylthioadenosine phosphorylase (MTAP) KO cells, both in vitro
and in vivo, providing further evidence to support the utility of
MAT2a inhibitors as potential anticancer therapies for MTAP-deficient
tumors