Cell signaling actions mediated by reduction-oxidation (redox)-dependent post-translational modifications include the oxidation, glutathionylation, S-nitrosation, and alkylation of cysteine. These reactions intimately link metabolic and inflammatory status with changes in cell and organ function, since many enzymes, receptors and transcriptional regulatory proteins mediating metabolic and inflammatory responses contain functionally- significant hyperactive cysteine thiols. Particular focus is being placed on reaction mediated by nitric oxide (NO), nitrite (NO2-) and nitrate (NO3-) and secondary nitrogen oxides and the unique redox signaling responses they induce via fatty acid nitration reactions. The nature and amounts of various nitrogen oxides generated endogenously are dependent on inflammatory status, diet, acidic microenvironments and NO3--reducing enter salivary bacterial populations. Many of these products are chemically-reactive and generate protein NO- home complexes, protein Cys-NO adducts (RSNO) and in the research plan, electrophilic fatty acid nitroalkenes (NO2-FA) that readily and reversibly alkylate susceptible protein thiols. The cGMP-independent pleiotropic signaling actions of NO2-FAs induce adaptive tissue responses that include beneficial shifts in adipokine and cytokine expression, restoration of insulin sensitivity and the attenuation of airway hyperactivity. This motivated us to hypothesize that the promotion of nitro-fatty acid signaling alleviates metabolic syndrome-induced hypertension and its pulmonary complications. To test this concept, a de- risked drug strategy will be evaluated by pursuing both mechanistically-revealing model system studies and a blinded crossover design Phase 2 clinical study:
Aim #1 - Identify the sites of NO2-FA adduction in the lung tissue of obese mice with airway hyperactivity and define the biochemical and physiological responses to oral NO2-FA administration.
Aim #2 - Evaluate the clinical responses of obese asthmatic patients to the orally-administered NO2-FA, 10-nitro-octadeca-9-enoic acid (NO2-OA). We will identify key sites of NO2-FA-induced PTMs in the lungs of obese mice with airway hyperactivity (AHR) and define how this affects redox-sensitive transcription factor (TF) function, gene expression profiles and activities of critical enzyme targets. Current data support that NO2-FA-mediated PTMs promote salutary responses in murine models of pulmonary inflammation and AHR. Both IV and oral formulations of NO2-FA have undergone extensive preclinical toxicology and pharmacokinetics evaluation and are in FDA-approved Phase 1 testing in humans. The physiological and biochemical responses of obese asthmatics to NO2-FA will be studied in a blinded, placebo-controlled crossover study. These responses to NO2-FA are anticipated to be more efficacious than many single-target asthma drugs, because the pleiotropic anti-inflammatory signaling actions of NO2-FA are expected to strike a pharmacological chord, rather than a note, in this complex inflammatory phenotype.
The research plan is designed to test the beneficial metabolic and anti-inflammatory actions or an endogenously present class of modified fats, termed nitro-fatty acids. These molecules are also present in plants and natural oils, and are formed during digestion and inflammatory reactions. Because of the potent tissue-protective actions of nitro-fatty acids, they are being developed as new drug candidates and, in this proposed study, are being tested for an ability to treat obese individuals with asthma - a medical problem that has limited therapeutic options.
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