Immunotoxicology Laboratory - Dr. Jared Brown

Research in the Brown lab broadly focuses on immune responses to environmental and occupational exposures. Our research ranges from understanding immune responses to nanoparticles and air pollution to chemical warfare agents and occupational exposures. In addition, we are interested in developing novel nanotherapeutics for treatment of cancer and allergic disease. Examples of current projects in the Brown lab are described below:

1. Understanding mechanisms of non-IgE mast cell activation by environmental particulates.

This work, funded by NIEHS R01 ES019311, is examining novel mechanisms by which nanoparticles and airborne particulate matter trigger non-IgE mast cell activation contributing to adverse pulmonary and cardiovascular outcomes. Specifically, we are investigating redox and non-redox mechanisms linked with thioredoxin interacting protein and its potential regulatory role in mast cell degranulation. In addition, we are interested in cellular metabolism changes which occur between IgE and non-IgE mast cell degranulation that may provide insight into disease mechanisms in mast cell activation disorders. Lastly, we are working with Drs. Stephen Dreskin and Jenny Stitt from the Anschutz School of Medicine to examine these mechanisms of non-IgE mast cell degranulation in patients with chronic idiopathic urticaria.

2. Silica Nephropathy and Chronic Kidney Disease of Unknown Etiology.

This work, funded by NIDDK R01 DK12351 and in collaboration with Drs. Richard Johnson and Carlos Roncal within the School of Medicine, is examining the contribution of inhaled silica nanoparticles produced during burning of sugarcane fields in the development of chronic kidney disease of unknown etiology (CKDu). CKDu is worldwide epidemic largely associated with coastal agricultural workers leading to chronic kidney disease in young individuals and often resulting in kidney transplant or death. There are many potential contributing factors including heat stress, dehydration and environmental exposures. We are currently examining kidney biopsy sections from CKDu patients for the presence of silica nanoparticles that are found in high abundance in the ash from sugarcane burning. We are using two novel techniques to identify silica nanoparticles in biopsy sections: 1) single particle inductively coupled plasma mass spectrometry to provide size and chemical information on the silica nanoparticles and 2) enhanced darkfield hyperspectral imaging to image nanoparticles in tissue. In addition, we are using a human proximal convoluted tubule cells and animal models to investigate potential mechanisms of toxicity by sugarcane ash and purified amorphous silica nanoparticles.

3. Contribution of mast cells to nitrogen mustard pulmonary and central nervous system toxicity.

This work, funded by the NIEHS and the Department of Defense and working with Dr. Neera Tewari-Singh (Michigan State University), is investigating the role of mast cells in mediating inflammation in response to exposure to sulphur mustard and phosgene oxime, both of which are chemical warfare agents. We have utilized a mouse model of mast cell deficiency to demonstrate that in the absence of mast cells that inflammation resulting from sulphur mustard exposure is largely diminished. In addition, we are examining the effects of mast cell activation in the brain following sulphur mustard exposure. Lastly, we developing a nanoparticle based therapeutic to prevent mast cell activation as a prophylactic treatment for military personnel and civilians to prevent the effects of chemical warfare agents.

4. Contribution of environmental and occupational exposures to impaired treatment of bladder cancer.

This project is aimed at understanding how environmental and occupational exposures impact bladder cancer treatment. We are working with Drs. Tom Flaig, John Adgate and Myles Cockburn on this project. Immune checkpoint inhibitor antibodies (directed at PD1/PDL1) are currently approved for bladder cancer but are only effective in ~20% of patients. Our goal is to understand why 80% of patients do not respond to these treatments and if there is an influence of environmental exposures (particularly air pollution) on these treatment response rates. We have hypothesized that modulation of the immune response by environmental exposures may contribute to this clinical observation. To test this hypothesis, we are following bladder cancer patients undergoing treatment and examining their exposure levels as well as developing a mouse model to investigate this hypothesis.

5. Development of designer nanoparticle for treatment of bladder cancer.

This project is funded by the Department of Defense and is in collaboration with Drs. Carlos Catalano and Tom Flaig. Our goal is to develop a novel bacteriophage like nanoparticle (Phage like particle, PLP) for the treatment of bladder cancer. The PLP is targeted to bladder cancer cells and designed to deliver an agonist of the STING pathway to activate an anti-tumor immune response through production of type 1 interferons.

6. The effect of coal and mine respirable dust on lung cells and exposure assessment.

This project, funded by the Alpha Foundation, and in collaboration with Drs. Candace Tsai (UCLA) and Jurgen Brune (Colorado School of Mines) is investigating the contribution of nano-sized fraction of coal dust to lung disease. There has been an increase in lung disease in coal miners in recent years due to changes in mining practices. We have hypothesized that there is an increase in generation of nano-sized coal dust that contributes to the increase in lung disease. We are using an air-liquid interface of human lung epithelial cells to investigate various nano-sized fractions of coal dust toxicity.

7. Inductively coupled plasma mass spectrometry studies:

We have a number of funded collaborations with various investigators including Drs. Anne Starling (CSPH), Kathy James (CSPH), James Roede to measure metal levels in various human, animal and cell samples. We have also developed a single particle ICP-MS method to measure nanoparticles in tissue and cells and have the capability to speciate metals such as arsenic.

Equipment available for use in the Nanotoxicology laboratory includes:

• CytoViva Hyperspectral Microscope 
• DMT pressure myograph system
• Olympus IX73 inverted microscope
• BD Accuri C6 Flow Cytometer
• ABI Step-One Plus Real Time PCR instrument
• BioTek Synergy HT microplate reader
• Qsonica cup horn sonicator with enclosure
• NanoDrop 2000 spectrophotometer
• Mettler-Toledo XP6 automated microbalance
• Cell Culture Facility with 3 laminar flow hoods, incubators, inverted microscope and centrifuges
• Nexcelom Auto X4 Automated Cell Counter
• Shandon Cytospin IV
• Small animal surgical room and monitoring equipment
• Zeiss dissecting microscope
• Eppendorf PCR machine
• Ultrasonic processor
• GentleMACS tissue dissociator and magnetic cell separation equipment
• Perkin Elmer NexION 2000 single particle and single cell ICP-MS
• Lonza Nucleofector 2b Electroporation Device
• Perkin Elmer Titan MPS Microwave Preparation system for ICP-MS