Inhaled Mine-Site Derived Metal Particulate Matter Drives Pulmonary and Systemic Immune Dysregulation

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Project Summary/Abstract Inhalation of mine site dust is a relevant route of human exposure to metal mixtures that poses a significant health concern for tribal communities living near abandoned uranium and hard rock mine sites in the four- corners region of the Southwestern United States. The University of New Mexico's Metals Exposure and Toxicity Assessment on Tribal Land in the Southwest (UNM METALS) team has demonstrated that exposure of individuals in the Navajo Nation to metal mixtures is associated with biomarkers of immune dysregulation and living in close proximity to abandoned uranium mines correlates with levels of anti-nuclear autoantibodies. This region is also a geographic epicenter for interstitial lung disease, silicosis and other chronic respiratory disorders, which are linked to environmental exposures and systemic autoimmunity. It is currently not known how inhaled metal-rich particulates drive extrapulmonary immunological dysregulation. In addition, the contribution of different individual metals (e.g., uranium, vanadium, and iron) in driving these immune-mediated changes has yet to be clearly defined. BioProject – Lung (BP Lung) focuses on investigating mechanisms of metal-mediated immune dysregulation both locally in the lungs, as well as systemically following inhalation exposure to metal-rich particulates. Thus, our main objective is to determine how these changes contribute to pulmonary injury and autoimmune development. Because metals accumulate in bone and we have evidence that inflammatory changes in the bone marrow niche mirror pulmonary responses following particulate exposure, a second goal is to investigate crosstalk between the bone marrow niche and the lungs contributing to metal particulate-mediated immune dysfunction. Our central hypothesis is that uranium and uranium-rich particulate mixtures drive pulmonary and systemic immune dysregulation and autoimmunity through hyperactive NETosis, in part by priming neutrophils for NETosis in the bone marrow niche. In Aim 1, we will utilize a novel high content imaging, machine learning-based single cell platform to investigate how individual metals alone or in combination with other metals and minerals contribute to oxidative stress, inflammation, and NETosis using human, in vitro models. In Aim 2, we will use an autoimmune prone mouse model to determine the role of neutrophils and NETosis in the development of airborne metal-mediated lung and systemic immune dysregulation and autoimmune development using several established NETosis inhibitors. In Aim 3, we will translate our mechanistic findings from Aims 1 and 2 to investigate associations between airborne metal exposure and airway inflammatory mediators in individuals from Laguna Pueblo partnering community in collaboration with BP Comm and CEC. This work is innovative and significant because it utilizes state-of-the art tools to provide detailed understanding of the effect of neutrophils and NETosis as mechanistic targets and driver of systemic immune dysregulation following metal particulate exposure and how crosstalk between the bone marrow niche and the lungs contribute to these pathologies.