20 research outputs found
Profiling Reactive Metabolites via Chemical Trapping and Targeted Mass Spectrometry
Metabolomic profiling studies aim
to provide a comprehensive, quantitative,
and dynamic portrait of the endogenous metabolites in a biological
system. While contemporary technologies permit routine profiling of
many metabolites, intrinsically labile metabolites are often improperly
measured or omitted from studies due to unwanted chemical transformations
that occur during sample preparation or mass spectrometric analysis.
The primary glycolytic metabolite 1,3-bisphosphoglyceric acid (1,3-BPG)
typifies this class of metabolites, and, despite its central position
in metabolism, has largely eluded analysis in profiling studies. Here
we take advantage of the reactive acylphosphate group in 1,3-BPG to
chemically trap the metabolite with hydroxylamine during metabolite
isolation, enabling quantitative analysis by targeted LC–MS/MS.
This approach is compatible with complex cellular metabolome, permits
specific detection of the reactive (1,3-) instead of nonreactive (2,3-)
BPG isomer, and has enabled direct analysis of dynamic 1,3-BPG levels
resulting from perturbations to glucose processing. These studies
confirmed that standard metabolomic methods misrepresent cellular
1,3-BPG levels in response to altered glucose metabolism and underscore
the potential for chemical trapping to be used for other classes of
reactive metabolites
Proteome-Wide Reactivity Profiling Identifies Diverse Carbamate Chemotypes Tuned for Serine Hydrolase Inhibition
Serine
hydrolases are one of the largest and most diverse enzyme
classes in Nature. Inhibitors of serine hydrolases are used to treat
many diseases, including obesity, diabetes, cognitive dementia, and
bacterial and viral infections. Nonetheless, the majority of the 200+
serine hydrolases in mammals still lack selective inhibitors for their
functional characterization. We and others have shown that activated
carbamates, through covalent reaction with the conserved serine nucleophile
of serine hydrolases, can serve as useful inhibitors for members of
this enzyme family. The extent to which carbamates, however, cross-react
with other protein classes remains mostly unexplored. Here, we address
this problem by investigating the proteome-wide reactivity of a diverse
set of activated carbamates <i>in vitro</i> and <i>in vivo</i>, using a combination of competitive and click chemistry
(CC)-activity-based protein profiling (ABPP). We identify multiple
classes of carbamates, including <i>O</i>-aryl, <i>O</i>-hexafluoroisopropyl (HFIP), and <i>O</i>-<i>N</i>-hydroxysuccinimidyl (NHS) carbamates that react selectively
with serine hydrolases across entire mouse tissue proteomes <i>in vivo</i>. We exploit the proteome-wide specificity of HFIP
carbamates to create <i>in situ</i> imaging probes for the
endocannabinoid hydrolases monoacylglycerol lipase (MAGL) and α-β
hydrolase-6 (ABHD6). These findings, taken together, designate the
carbamate as a privileged reactive group for serine hydrolases that
can accommodate diverse structural modifications to produce inhibitors
that display exceptional potency and selectivity across the mammalian
proteome
Korean survey data reveals an association of chronic laryngitis with tinnitus in men
<div><p>The association between chronic laryngitis and tinnitus is not a well-studied topic, unlike the association of these two conditions with many other disorders. Cross-sectional data of 11,347 adults (males: 4,934; females: 6,413), who completed the Korea National Health and Nutrition Examination Survey (KNHANES) from 2010 to 2012 were used to investigate this association. Lifestyle patterns, including smoking and alcohol habits, regular exercise, physical and mental health status, socioeconomic status, nutritional status, and other chronic diseases, were analyzed. Chronic laryngitis and tinnitus were diagnosed by field survey teams, which included otolaryngologists, who conducted chronic disease surveillance using a health status interview, a nutritional status questionnaire, and a physical examination. Chronic laryngitis was significantly associated with age, education beyond high school, depressed mood, voice change, metabolic syndrome, and tinnitus in men. In women, chronic laryngitis was associated with body mass index and diabetes mellitus. Chronic laryngitis in men was significantly associated with tinnitus (odds ratio 1.671, [95% confidence interval: 1.167–2.393]) after adjusting for age, body mass index, smoking status, alcohol intake, regular exercise, metabolic syndrome, education beyond high school, and depressed mood. Additionally, the prevalence of chronic laryngitis increased with increasing severity of tinnitus in men alone (P = 0.002). The study revealed a significant association between chronic laryngitis and tinnitus.</p></div
Analysis of factors associated with tinnitus according to sex.
<p>Analysis of factors associated with tinnitus according to sex.</p
Analysis of factors associated with chronic laryngitis, according to sex.
<p>Analysis of factors associated with chronic laryngitis, according to sex.</p
Logistic regression models of tinnitus for chronic laryngitis.
<p>Logistic regression models of tinnitus for chronic laryngitis.</p
Prevalence of chronic laryngitis according to the severity of tinnitus in men and women.
<p>Prevalence of chronic laryngitis according to the severity of tinnitus in men and women.</p
Discovery and Optimization of Piperidyl-1,2,3-Triazole Ureas as Potent, Selective, and in Vivo-Active Inhibitors of α/β-Hydrolase Domain Containing 6 (ABHD6)
α/β-Hydrolase
domain containing 6 (ABHD6) is a transmembrane
serine hydrolase that hydrolyzes the endogenous cannabinoid 2-arachidonoylglycerol
(2-AG) to regulate certain forms of cannabinoid receptor-dependent
signaling in the nervous system. The full spectrum of ABHD6 metabolic
activities and functions is currently unknown and would benefit from
selective, in vivo-active inhibitors. Here, we report the development
and characterization of an advanced series of irreversible (2-substituted)-piperidyl-1,2,3-triazole
urea inhibitors of ABHD6, including compounds KT182 and KT203, which
show exceptional potency and selectivity in cells (<5 nM) and,
at equivalent doses in mice (1 mg kg<sup>–1</sup>), act as
systemic and peripherally restricted ABHD6 inhibitors, respectively.
We also describe an orally bioavailable ABHD6 inhibitor, KT185, that
displays excellent selectivity against other brain and liver serine
hydrolases in vivo. We thus describe several chemical probes for biological
studies of ABHD6, including brain-penetrant and peripherally restricted
inhibitors that should prove of value for interrogating ABHD6 function
in animal models
Activity-Based Protein Profiling of Oncogene-Driven Changes in Metabolism Reveals Broad Dysregulation of PAFAH1B2 and 1B3 in Cancer
Targeting dysregulated metabolic
pathways is a promising therapeutic strategy for eradicating cancer.
Understanding how frequently altered oncogenes regulate metabolic
enzyme targets would be useful in identifying both broad-spectrum
and targeted metabolic therapies for cancer. Here, we used activity-based
protein profiling to identify serine hydrolase activities that were
consistently upregulated by various human oncogenes. Through this
profiling effort, we found oncogenic regulatory mechanisms for several
cancer-relevant serine hydrolases and discovered that platelet activating
factor acetylhydrolase 1B2 and 1B3 (PAFAH1B2 and PAFAH1B3) activities
were consistently upregulated by several oncogenes, alongside previously
discovered cancer-relevant hydrolases fatty acid synthase and monoacylglycerol
lipase. While we previously showed that PAFAH1B2 and 1B3 were important
in breast cancer, our most recent profiling studies have revealed
that these enzymes may be dysregulated broadly across many types of
cancers. Here, we find that pharmacological blockade of both enzymes
impairs cancer pathogenicity across multiple different types of cancer
cells, including breast, ovarian, melanoma, and prostate cancer. We
also show that pharmacological blockade of PAFAH1B2 and 1B3 causes
unique changes in lipid metabolism, including heightened levels of
tumor-suppressing lipids. Our results reveal oncogenic regulatory
mechanisms of several cancer-relevant serine hydrolases using activity-based
protein profiling, and we show that PAFAH1B2 and 1B3 are important
in maintaining cancer pathogenicity across a wide spectrum of cancer
types
Activity-Based Protein Profiling of Oncogene-Driven Changes in Metabolism Reveals Broad Dysregulation of PAFAH1B2 and 1B3 in Cancer
Targeting dysregulated metabolic
pathways is a promising therapeutic strategy for eradicating cancer.
Understanding how frequently altered oncogenes regulate metabolic
enzyme targets would be useful in identifying both broad-spectrum
and targeted metabolic therapies for cancer. Here, we used activity-based
protein profiling to identify serine hydrolase activities that were
consistently upregulated by various human oncogenes. Through this
profiling effort, we found oncogenic regulatory mechanisms for several
cancer-relevant serine hydrolases and discovered that platelet activating
factor acetylhydrolase 1B2 and 1B3 (PAFAH1B2 and PAFAH1B3) activities
were consistently upregulated by several oncogenes, alongside previously
discovered cancer-relevant hydrolases fatty acid synthase and monoacylglycerol
lipase. While we previously showed that PAFAH1B2 and 1B3 were important
in breast cancer, our most recent profiling studies have revealed
that these enzymes may be dysregulated broadly across many types of
cancers. Here, we find that pharmacological blockade of both enzymes
impairs cancer pathogenicity across multiple different types of cancer
cells, including breast, ovarian, melanoma, and prostate cancer. We
also show that pharmacological blockade of PAFAH1B2 and 1B3 causes
unique changes in lipid metabolism, including heightened levels of
tumor-suppressing lipids. Our results reveal oncogenic regulatory
mechanisms of several cancer-relevant serine hydrolases using activity-based
protein profiling, and we show that PAFAH1B2 and 1B3 are important
in maintaining cancer pathogenicity across a wide spectrum of cancer
types