Identification and characterization of small-molecule inhibitors of aldehyde dehydrogenase 1A1

Indiana University-Purdue University Indianapolis (IUPUI)The human genome encodes 19 members of the aldehyde dehydrogenase (ALDH) superfamily, critical enzymes involved in the metabolism of aldehyde substrates. A major function of the ALDH1A subfamily is the oxidation of retinaldehyde to retinoic acid, a key regulator of numerous cell growth and differentiation pathways. ALDH1A1 has been identified as a biomarker for both normal stem cells and cancer stem cells. Small molecule probes are needed to better understand the role of this enzyme in both normal and disease states. However, there are no commercially available, small molecules that selectively inhibit ALDH1A1. Our goal is to identify and characterize small molecule inhibitors of ALDH1A1 as chemical tools and as potential therapeutics. To better understand the basis for selective inhibition of ALDH1A1, we characterized N,N-diethylaminobenzaldehyde (DEAB), which is a commonly used inhibitor of ALDH1A1 and purported to be selective. DEAB serves as the negative control for the Aldefluor assay widely utilized to identify stem cells. Rather than being a selective inhibitor for ALDH1A1, we found that DEAB is a slow substrate for multiple ALDH isoenzymes, and depending on the rate of turnover, DEAB behaves as either a traditional substrate or as an inhibitor. Due to its very slow turnover, DEAB is a potent inhibitor of ALDH1A1 with respect to propionaldehyde oxidation, but it is not a good candidate for the development of selective ALDH1A1 inhibitors because of its promiscuity. Next, to discover novel selective inhibitors, we used an in vitro, high-throughput screen of 64,000 compounds to identify 256 hits that either activate or inhibit ALDH1A1 activity. We have characterized two structural classes of compounds, CM026 and CM037, using enzyme kinetics and X-ray crystallographic structural data. Both classes contained potent and selective inhibitors for ALDH1A1. Structural studies of ALDH1A1 with CM026 showed that CM026 binds at the active site, and its selectivity is achieved by a single residue substitution. Importantly, CM037 selectively inhibits proliferation of ALDH+ ovarian cancer cells. The discovery of these two selective classes of ALDH1A1 inhibitors may be useful in delineating the role of ALDH1A1 in biological processes and may seed the development of new chemotherapeutic agents

TRADABLE PERMITS FOR CONTROLLING NITRATES IN GROUNDWATER AT THE FARM LEVEL: A CONCEPTUAL MODEL

Nitrate contamination of municipal and domestic well water supplies is becoming an increasing problem in many rural and urban areas, raising the cost of providing safe drinking water. The objective of this paper is to describe a marketable permit scheme that can effectively manage nitrate pollution of groundwater supplies for communities in rural areas without hindering agricultural production in watersheds. They key to implementing this scheme is being able to link nitrate leaching from nitrogen fertilizer applied to crops at a farm to nitrate levels measured at a drinking water well.agriculture, groundwater pollution, leaching, nitrates, pollution trading, Environmental Economics and Policy,

Toward Prescriptive Alternatives to Secondary School Suspensions: Risk Analysis Using an Epidemiologic Approach.

Data were collected from a large urban high school in order to investigate the characteristics of students who get suspended. Descriptive, epidemiologic analyses, and multivariate statistical analyses were used to investigate which, if any of several screening variables were most likely to predict secondary school suspensions for 9th grade students. Because multivariate statistics may be tedious for many to interpret, epidemiologic analyses were used in order to more easily disseminate study findings to readers and those within the school setting. For males, statistics were calculated for three groups of students: (1) males having more than one 9th grade suspension, (2) males having any 9th grade suspensions, and (3) males having no 9th grade suspensions. For females, statistics were calculated for two groups of students: (1) females having any 9th grade suspensions, and (2) females having no 9th grade suspensions. Overall, students having at least one suspension during their 8th grade year were found to be at greater risk for suspension during the 9th grade. Analyses conducted across gender indicated that males were over three times more likely to be suspended than females. Also, the variables associated with an increase in the likelihood of suspension for males and females were different. More specifically, for males having any 9th grade suspensions, a GPA of 1.60 or lower, any suspensions during the 8th grade, a significant score on the SSRS, and any significant score on subscales of the Youth Self-Report (YSR) were associated with an increase in the likelihood of suspension. Importantly, analyses also indicated that males with more than one suspension were found to have a greater incidence of reading deficits and absences during the 8th grade than males with only one or no suspensions. For females, suspensions during the 8th grade, a significant score on any subscale of the Child Behavior Checklist (CBCL), absences during the 8th grade, significant scores on subscales of the Youth Self-Report (YSR), and a significant score on the Reynolds Adolescent Depression Scale (RADS) were associated with an increase in the likelihood of 9th grade suspension

Development of a high-throughput in vitro assay to identify selective inhibitors for human ALDH1A1

The human aldehyde dehydrogenase (ALDH) superfamily consists of at least 19 enzymes that metabolize endogenous and exogenous aldehydes. Currently, there are no commercially available inhibitors that target ALDH1A1 but have little to no effect on the structurally and functionally similar ALDH2. Here we present the first human ALDH1A1 structure, as the apo-enzyme and in complex with its cofactor NADH to a resolution of 1.75 and 2.1Å, respectfully. Structural comparisons of the cofactor binding sites in ALDH1A1 with other closely related ALDH enzymes illustrate a high degree of similarity. In order to minimize discovery of compounds that inhibit both isoenzymes by interfering with their conserved cofactor binding sites, this study reports the use of an in vitro, NAD(+)-independent, esterase-based high-throughput screen (HTS) of 64,000 compounds to discover novel, selective inhibitors of ALDH1A1. We describe 256 hits that alter the esterase activity of ALDH1A1. The effects on aldehyde oxidation of 67 compounds were further analyzed, with 30 selectively inhibiting ALDH1A1 compared to ALDH2 and ALDH3A1. One compound inhibited ALDH1A1 and ALDH2, while another inhibited ALDH1A1, ALDH2, and the more distantly related ALDH3A1. The results presented here indicate that this in vitro enzyme activity screening protocol successfully identified ALDH1A1 inhibitors with a high degree of isoenzyme selectivity. The compounds identified via this screen plus the screening methodology itself represent a starting point for the development of highly potent and selective inhibitors of ALDH1A1 that may be utilized to better understand the role of this enzyme in both normal and disease states

Characterization of Two Distinct Structural Classes of Selective Aldehyde Dehydrogenase 1A1 Inhibitors.

Aldehyde dehydrogenases (ALDH) catalyze the irreversible oxidation of aldehydes to their corresponding carboxylic acid. Alterations in ALDH1A1 activity are associated with such diverse diseases as cancer, Parkinson?s disease, obesity, and cataracts. Inhibitors of ALDH1A1 could aid in illuminating the role of this enzyme in disease processes. However, there are no commercially available selective inhibitors for ALDH1A1. Here we characterize two distinct chemical classes of inhibitors that are selective for human ALDH1A1 compared to eight other ALDH isoenzymes. The prototypical members of each structural class, CM026 and CM037, exhibit submicromolar inhibition constants but have different mechanisms of inhibition. The crystal structures of these compounds bound to ALDH1A1 demonstrate that they bind within the aldehyde binding pocket of ALDH1A1 and exploit the presence of a unique glycine residue to achieve their selectivity. These two novel and selective ALDH1A1 inhibitors may serve as chemical tools to better understand the contributions of ALDH1A1 to normal biology and to disease states

ATD-2 Integrated Arrival/Departure/Surface (IADS) System Software Version 3.1.x Releases and Notes

This document summarizes the change reports for the ATD-2 V3.1.x series of software releases to Charlotte-Douglas International Airport (CLT). These list all the changes since the previous release. The Release Notes for Distribution are meant to be more readable by stakeholders. [Includes updates to changes for RTC (Ramp Traffic Console), Scheduler, STBO (Surface Trajectory-Based Operations), and Surface Metering Display (graphical-user interface, GUI) clients.

Physician attitudes towards-and adoption of-mobile health

OBJECTIVE: Smartphone apps and mobile devices are an emerging method of healthcare data collection. This study sought to understand how physicians currently view mobile health (mHealth) technologies and use them in patient care. METHODS: A total of 186 physicians affiliated with Washington University School of Medicine in St. Louis, Missouri, USA completed a survey in 2016 regarding their current implementation of mHealth technologies for patient care and support for further development. RESULTS: More than half of respondents were willing to discuss health apps and mobile devices with patients. However, most were not currently recommending them to patients. Apps/devices that encouraged a healthy diet and weight or tracked heart rate received the highest satisfaction ratings. Apps/devices that accessed the EMR (electronic medical record) remotely, provided medication reminders, or enrolled research subjects garnered the most interest despite respondents lacking prior experience. A majority agreed that collected biometrics are useful for promoting a healthy lifestyle (68%), tracking medical treatment (64%), or conducting research (56%); and agreed that proof of accuracy and precision (81%) and the efficient integration of collected data (68%) are necessary improvements. Uploading data automatically and updating physicians in real-time was the most preferred method of data integration into the EMR. CONCLUSIONS: Physicians show interest in using mHealth technologies for patient care but have limited experience, usually with those specific to their specialties. Proof of quality and a method to integrate data into the EMR are necessary for a mainstream role in healthcare

N,N-diethylaminobenzaldehyde (DEAB) as a substrate and mechanism-based inhibitor for human ALDH isoenzymes

N,N-diethylaminobenzaldehyde (DEAB) is a commonly used "selective" inhibitor of aldehyde dehydrogenase isoenzymes in cancer stem cell biology due to its inclusion as a negative control compound in the widely utilized Aldefluor assay. Recent evidence has accumulated that DEAB is not a selective inhibitory agent when assayed in vitro versus ALDH1, ALDH2 and ALDH3 family members. We sought to determine the selectivity of DEAB toward ALDH1A1, ALDH1A2, ALDH1A3, ALDH1B1, ALDH1L1, ALDH2, ALDH3A1, ALDH4A1 and ALDH5A1 isoenzymes and determine the mechanism by which DEAB exerts its inhibitory action. We found that DEAB is an excellent substrate for ALDH3A1, exhibiting a Vmax/KM that exceeds that of its commonly used substrate, benzaldehyde. DEAB is also a substrate for ALDH1A1, albeit an exceptionally slow one (turnover rate ∼0.03 min(-1)). In contrast, little if any turnover of DEAB was observed when incubated with ALDH1A2, ALDH1A3, ALDH1B1, ALDH2 or ALDH5A1. DEAB was neither a substrate nor an inhibitor for ALDH1L1 or ALDH4A1. Analysis by enzyme kinetics and QTOF mass spectrometry demonstrates that DEAB is an irreversible inhibitor of ALDH1A2 and ALDH2 with apparent bimolecular rate constants of 2900 and 86,000 M(-1) s(-1), respectively. The mechanism of inactivation is consistent with the formation of quinoid-like resonance state following hydride transfer that is stabilized by local structural features that exist in several of the ALDH isoenzymes

What Can Parents Do? A Review of State Laws Regarding Decision Making for Adolescent Drug Abuse and Mental Health Treatment

This study examined US state laws regarding parental and adolescent decision-making for substance use and mental health inpatient and outpatient treatment. State statues for requiring parental consent favored mental health over drug abuse treatment and inpatient over outpatient modalities. Parental consent was sufficient in 53%–61% of the states for inpatient treatment, but only for 39% – 46% of the states for outpatient treatment. State laws favored the rights of minors to access drug treatment without parental consent, and to do so at a younger age than for mental health treatment. Implications for how these laws may impact parents seeking help for their children are discussed