Schizophrenia, clinical and basic research at NIMH: A 75 Year retrospective.

Objective: In 2024, NIMH is celebrating its 75th anniversary. At the Congressional hearings preceding its initial funding in 1949, witnesses stressed the need for NIMH to carry out clinical and basic research to find the causes and better treatments for severe mental illnesses. Patients with schizophrenia alone were said to occupy one quarter of all hospital beds in the U.

Liquid application dosing alters the physiology of air-liquid interface (ALI) primary human bronchial epithelial cell/lung fibroblast co-cultures and testing relevant endpoints.

Differentiated primary human bronchial epithelial cell (dpHBEC) cultures grown under air-liquid interface (ALI) conditions exhibit key features of the human respiratory tract and are thus critical for respiratory research as well as efficacy and toxicity testing of inhaled substances (, consumer products, industrial chemicals, and pharmaceuticals). Many inhalable substances (, particles, aerosols, hydrophobic substances, reactive substances) have physiochemical properties that challenge their evaluation under ALI conditions . Evaluation of the effects of these methodologically challenging chemicals (MCCs) is typically conducted by "liquid application," involving the direct application of a solution containing the test substance to the apical, air-exposed surface of dpHBEC-ALI cultures.

The NIMH Research Portfolio: An Update.

To examine the funding priorities of the National Institute of Mental Health (NIMH) since 2016 to assess whether NIMH was continuing to prioritize basic research at the expense of clinical research. Six psychiatric disorders (schizophrenia, bipolar disorder, depression, anxiety disorders, eating disorders, autism) were assessed using 2 publicly available data sources (ClinicalTrials.gov and the National Institutes of Health Research, Condition, and Disease Categorization [RCDC]) to determine the degree of NIMH support for drug trials and research on these disorders in general since 2016.

Mucus increases cell iron uptake to impact the release of pro-inflammatory mediators after particle exposure.

We tested the hypothesis that (1) mucus production can be included in the cell response to iron deficiency; (2) mucus binds iron and increases cell metal uptake; and subsequently (3) mucus impacts the inflammatory response to particle exposure. Using quantitative PCR, RNA for both MUC5B and MUC5AC in normal human bronchial epithelial (NHBE) cells decreased following exposures to ferric ammonium citrate (FAC). Incubation of mucus-containing material collected from the apical surface of NHBE cells grown at air-liquid interface (NHBE-MUC) and a commercially available mucin from porcine stomach (PORC-MUC) with iron demonstrated an in vitro capacity to bind metal.

Real-time redox adaptations in human airway epithelial cells exposed to isoprene hydroxy hydroperoxide.

While redox processes play a vital role in maintaining intracellular homeostasis by regulating critical signaling and metabolic pathways, supra-physiological or sustained oxidative stress can lead to adverse responses or cytotoxicity. Inhalation of ambient air pollutants such as particulate matter and secondary organic aerosols (SOA) induces oxidative stress in the respiratory tract through mechanisms that remain poorly understood. We investigated the effect of isoprene hydroxy hydroperoxide (ISOPOOH), an atmospheric oxidation product of vegetation-derived isoprene and a constituent of SOA, on intracellular redox homeostasis in cultured human airway epithelial cells (HAEC).

Liquid Application Dosing Alters the Physiology of Air-Liquid Interface Primary Bronchial Epithelial Cultures and In vitro Testing Relevant Endpoints.

Differentiated Primary human bronchial epithelial cell (dpHBEC) cultures grown under air-liquid interface (ALI) conditions exhibit key features of the human respiratory tract and are thus critical for respiratory research as well as efficacy and toxicity testing of inhaled substances (., consumer products, industrial chemicals, and pharmaceuticals). Many inhalable substances (.

Lactate Production can Function to Increase Human Epithelial Cell Iron Concentration.

Introduction: Under conditions of limited iron availability, plants and microbes have evolved mechanisms to acquire iron. For example, metal deficiency stimulates reprogramming of carbon metabolism, increasing activity of enzymes involved in the Krebs cycle and the glycolytic pathway. Resultant carboxylates/hydroxycarboxylates then function as ligands to complex iron and facilitate solubilization and uptake, reversing the metal deficiency.

Benchmark Dose Modeling Approaches for Volatile Organic Chemicals Using a Novel Air-Liquid Interface In Vitro Exposure System.

Inhalation is the most relevant route of volatile organic chemical (VOC) exposure; however, due to unique challenges posed by their chemical properties and poor solubility in aqueous solutions, in vitro chemical safety testing is predominantly performed using direct application dosing/submerged exposures. To address the difficulties in screening toxic effects of VOCs, our cell culture exposure system permits cells to be exposed to multiple concentrations at air-liquid interface (ALI) in a 24-well format. ALI exposure methods permit direct chemical-to-cell interaction with the test article at physiological conditions.

Diacetyl exposure disrupts iron homeostasis in animals and cells.

Objective: Several mechanisms have been proposed for the biological effect of diacetyl. We tested the postulate that animal and cell exposures to diacetyl are associated with a disruption in iron homeostasis.

Materials And Methods: Male, Sprague-Dawley rats were intratracheally-instilled with either distilled water or diacetyl.

Ozone Responsive Gene Expression as a Model for Describing Repeat Exposure Response Trajectories and Interindividual Toxicodynamic Variability In Vitro.

Inhaled chemical/material exposures are a ubiquitous part of daily life around the world. There is a need to evaluate potential adverse effects of both single and repeat exposures for thousands of chemicals and an exponentially larger number of exposure scenarios (eg, repeated exposures). Meeting this challenge will require the development and use of in vitro new approach methodologies (NAMs); however, 2 major challenges face the deployment of NAMs in risk assessment are (1) characterizing what apical outcome(s) acute assays inform regarding the trajectory to long-term events, especially under repeated exposure conditions, and (2) capturing interindividual variability as it informs considerations of potentially susceptible and/or vulnerable populations.

Ozone Reacts With Carbon Black to Produce a Fulvic Acid-Like Substance and Increase an Inflammatory Effect.

Exposure to ambient ozone has been associated with increased human mortality. Ozone exposure can introduce oxygen-containing functional groups in particulate matter (PM) effecting a greater capacity of the particle for metal complexation and inflammatory effect. We tested the postulate that (1) a fulvic acid-like substance can be produced through a reaction of a carbonaceous particle with high concentrations of ozone and (2) such a fulvic acid-like substance included in the PM can initiate inflammatory effects following exposure of respiratory epithelial (BEAS-2B) cells and an animal model (male Wistar Kyoto rats).

Supplementation with omega-3 fatty acids potentiates oxidative stress in human airway epithelial cells exposed to ozone.

Background: Dietary intake of the omega-3 family of polyunsaturated fatty acids (ω-3 FA) is associated with anti-inflammatory effects. However, unsaturated fatty acids are susceptible to oxidation, which produces pro-inflammatory mediators. Ozone (O) is a tropospheric pollutant that reacts rapidly with unsaturated fatty acids to produce electrophilic and oxidative mediators of inflammation.

Air pollutants disrupt iron homeostasis to impact oxidant generation, biological effects, and tissue injury.

Air pollutants cause changes in iron homeostasis through: 1) a capacity of the pollutant, or a metabolite(s), to complex/chelate iron from pivotal sites in the cell or 2) an ability of the pollutant to displace iron from pivotal sites in the cell. Through either pathway of disruption in iron homeostasis, metal previously employed in essential cell processes is sequestered after air pollutant exposure. An absolute or functional cell iron deficiency results.

A new cell culture exposure system for studying the toxicity of volatile chemicals at the air-liquid interface.

A cell culture exposure system (CCES) was developed to expose cells established at an air-liquid interface (ALI) to volatile chemicals. We characterized the CCES by exposing indigo dye-impregnated filter inserts inside culture wells to 125 ppb ozone (O) for 1 h at flow rates of 5 and 25 mL/min/well; the reaction of O with an indigo dye produces a fluorescent product. A 5-fold increase in fluorescence at 25 mL/min/well versus 5 mL/min/well was observed, suggesting higher flows were more effective.

ERK1/2 and p38 regulate inter-individual variability in ozone-mediated IL-8 gene expression in primary human bronchial epithelial cells.

Inter-individual variability is observed in all biological responses; however this variability is difficult to model and its underlying mechanisms are often poorly understood. This issue currently impedes understanding the health effects of the air pollutant ozone. Ozone produces pulmonary inflammation that is highly variable between individuals; but reproducible within a single individual, indicating undefined susceptibility factors.

The biological effect of asbestos exposure is dependent on changes in iron homeostasis.

Functional groups on the surface of fibrous silicates can complex iron. We tested the postulate that (1) asbestos complexes and sequesters host cell iron resulting in a disruption of metal homeostasis and (2) this loss of essential metal results in an oxidative stress and biological effect in respiratory epithelial cells. Exposure of BEAS-2B cells to 50 μg/mL chrysotile resulted in diminished concentrations of mitochondrial iron.

Air pollution particles and iron homeostasis.

Background: The mechanism underlying biological effects, including pro-inflammatory outcomes, of particles deposited in the lung has not been defined.

Major Conclusions: A disruption in iron homeostasis follows exposure of cells to all particulate matter including air pollution particles. Following endocytosis, functional groups at the surface of retained particle complex iron available in the cell.

Differential expression of pro-inflammatory and oxidative stress mediators induced by nitrogen dioxide and ozone in primary human bronchial epithelial cells.

Context: NO2 and O3 are ubiquitous air toxicants capable of inducing lung damage to the respiratory epithelium. Due to their oxidizing capabilities, these pollutants have been proposed to target specific biological pathways, but few publications have compared the pathways activated.

Objective: This work will test the premise that NO2 and O3 induce toxicity by activating similar cellular pathways.

Baseline Chromatin Modification Levels May Predict Interindividual Variability in Ozone-Induced Gene Expression.

Traditional toxicological paradigms have relied on factors such as age, genotype, and disease status to explain variability in responsiveness to toxicant exposure; however, these are neither sufficient to faithfully identify differentially responsive individuals nor are they modifiable factors that can be leveraged to mitigate the exposure effects. Unlike these factors, the epigenome is dynamic and shaped by an individual's environment. We sought to determine whether baseline levels of specific chromatin modifications correlated with the interindividual variability in their ozone (O3)-mediated induction in an air-liquid interface model using primary human bronchial epithelial cells from a panel of 11 donors.

Wood Smoke Particle Sequesters Cell Iron to Impact a Biological Effect.

The biological effect of an inorganic particle (i.e., silica) can be associated with a disruption in cell iron homeostasis.

Particle retention by respiratory epithelial cells is associated with persistent biological effect.

The biological effect of particles on respiratory epithelial cells involves, in part, the generation of an oxidative stress and a consequent cascade of reactions culminating in inflammatory mediator release. Whether there is either an immediate, transitory activation or a persistent response of the cells to the particles has not been established. We tested the postulate that respiratory epithelial cells exposed to wood smoke particle (WSP) would demonstrate increased oxidative stress and mediator release following re-seeding and propagation of the cells for two generations post-initial exposure.

High throughput technologies for the functional discovery of mammalian enhancers: new approaches for understanding transcriptional regulatory network dynamics.

Completion of the human and mouse genomes has inspired new initiatives to obtain a global understanding of the functional regulatory networks governing gene expression. Enhancers are primary regulatory DNA elements determining precise spatio- and temporal gene expression patterns, but the observation that they can function at any distance from the gene(s) they regulate has made their genome-wide characterization challenging. Since traditional, single reporter approaches would be unable to accomplish this enormous task, high throughput technologies for mapping chromatin features associated with enhancers have emerged as an effective surrogate for enhancer discovery.