RA research eyes role of agricultural dust

Farming is one of the most dangerous professions, not only because of accidents, but exposure to organic dust that becomes airborne and inhalable, particularly in large animal farming.

Jill Poole, MD, professor and chief of the UNMC Division of Allergy and Immunology, has been studying these exposures, and their effects on lung disease, for more than a decade. She said it’s well known that agriculture workers have high rates of airway inflammatory diseases including asthma-like disorders and chronic bronchitis as well as high rates of musculoskeletal diseases, including bone fractures.

What is not known are the mechanisms linking lung disease and arthritis.

A team of UNMC researchers recently studied the role of airborne biohazard and agriculture dust exposure in rheumatoid arthritis. They published a manuscript that showed how inhalation of agricultural exposure agents in mice causes a more exaggerated inflammatory lung disease, increased autoimmunity and arthritis.

The study, conducted over three years primarily in the laboratories of Dr. Poole, Ted Mikuls, MD, and Geoffrey Thiele, PhD, was published in PLOS ONE, a peer-reviewed scientific journal published by the Public Library of Science.

Rohit Gaurav, PhD, a postdoctoral fellow in Dr. Poole’s laboratory, was lead and corresponding author of the paper. Collaborators in rheumatology and co-authors of the paper included Dr. Mikuls, Dr. Thiele, Bryant England, MD, and Michael Duryee.

“Occupational-associated rheumatoid arthritis-lung disease is predominant among men, and agriculture exposures are one such risk factor,” said Dr. Poole, senior author on the paper. “Rheumatoid arthritis-associated lung disease is a devastating disease with high morbidity and mortality; novel biomarkers of disease identification and more treatment options are necessary.”

In the study, the team used cutting-edge technologies including work with the Next Generation Sequencing and Bioinformatics core facilities at UNMC.

“Key gene expression signatures were found,” Dr. Poole said. “This data gives us information on which cells to target to reduce disease manifestation and allows us to further investigate whether these cell gene signatures represent key biomarkers. We are looking to target these cells to potentially reduce the disease burden.”

She said airborne biohazards, including complex organic dusts in agriculture settings that induce lung inflammation, also are important in arthritis.

“The combination of arthritis and airborne biohazards can lead to disease manifestations,” Dr. Poole said. “These two exposures — airborne biohazards plus susceptibility to arthritis — dynamically interact to alter the lung environment toward pro-fibrosis processes that may be dependent on myeloid derived cells.”

“Rheumatoid arthritis and lung disease both have a common culprit, occupational or environmental exposure of airborne biohazards,” Dr. Gaurav said. “With our research, we investigated changes in immune cells of the lungs that contribute to disease progression resulting in poor quality of life and death with exposure to agricultural dust. Our findings have direct implications on the therapeutic direction for rheumatoid arthritis-associated lung disease.”

Other UNMC authors of the manuscript are Amy Nelson, Meng Niu, PhD, Chittibabu Guda, PhD, James Eudy, PhD, Austin Barry, Todd Wyatt, PhD, and Debra Romberger, MD.