Umadevi Sajjan, PhD

Research Interests

Research in Dr. Sajjan's lab is focused on airway epithelial cell biology and innate immune functions of conductive airway epithelium.

Airway epithelium in the upper respiratory tract is in direct contact with the external milieu and is equipped with powerful defense mechanisms to protect the lungs from inhaled pathogens and other environmental pollutants. The epithelium in the airways is complex with different cell types. After injury, tissue-specific stem cells known as airway basal cells rapidly divide and regenerate the complex airway epithelium. However, in patients with chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis (CF), airway epithelium is often abnormal, and this may be due to defects in regeneration mechanisms. 

Abnormal airway epithelium with altered structure or function may significantly affect the outcome of respiratory infections leading to progression of lung disease in these patients. Respiratory infections are the major causes of acute exacerbations that often lead to disease progression. For example, rhinovirus, which causes common colds in healthy individuals, exacerbates lung disease in this patient population.

The Sajjan laboratory is working to elucidate airway epithelial regenerative mechanisms that are defective in COPD. We want to understand how defective mechanisms influence the innate immune responses of airway epithelium to rhinovirus.

A related area of research in our lab is to determine the effects of quercetin, a plant polyphenol, in reducing lung inflammation and improve innate immunity in COPD patients. We are examining the effect of quercetin in correcting the regenerative pathways in COPD airway stem cells to promote normal regeneration of airway epithelium.

At present we are conducting a small phase II clinical trial to examine whether quercetin reduces the markers of inflammation in COPD patients. The samples generated from this trial will be used to determine the mechanisms by which quercetin improves lung health in COPD.   

Upper airway epithelium produces nitric oxide, which is one of the early defense mechanisms involved in killing inhaled viruses and bacteria.  CF patients show defects in nitric oxide generation, and this is thought to contribute to persistence of bacteria in their lungs. In CF lungs, bacteria persist as a biofilm, which is resistant to antibiotics. Nitric oxide disperses bacterial biofilm. Therefore, our laboratory is testing whether treatment with low dose of nitric oxide synergizes with antibiotics to irradicate colonized bacteria in patients with CF.

Educational Background

• Postdoctoral Fellowship, Biochemistry, Hospital for Sick Children, Toronto, Canada
• PhD, Biochemistry, Central Food Technological Research Institute, University of Mysore, India
• MSc, Biochemistry, Karnatak University, India
• BSc, Chemistry, Botany and Zoology, University of Mysore, India

Memberships

• American Thoracic Society
• American Association of Immunologists
• American Society for Microbiologists

Additional Publications

Sajjan, U.S., Newcomb, D.C., Lewis, T.C., Stahle, C.S., Hershenson, M.B.  Interactions of Respiratory Viruses with the Epithelium.  In: The Pulmonary Epithelium, J. Wiley and Sons, West Sussex, UK, 2008, Ch 12, 225-251.

Ganesan S, Sajjan U. Innate Immune responses of COPD airway epithelium. In: Emphysema InTech, Croatia. 2011, Ch 2, 19-48.

Ganesan S, Sajjan US. Host evasion by Burkholderia cenocepacia. Front Cell Infect Micobiol 2011; 1: 25.

Sajjan US. Susceptibility to viral infections in COPD: Role of epithelial cells. Curr. Opi. Pulm. Med. 2012, 19:125-32

Ganesan S, Comstock AT, and Sajjan U Barrier function of airway tract epithelium. Tissue Barriers 2013 Oct 1;1(4):e24997.

Ganesan S, and Sajjan U Airway epithelial repair and remodeling in COPD Curr. Rep Respir Care 2013 Sep 1;2(3). doi: 10.1007/s13665-013-0052-2.

Kinker B, Comstock AT and Sajjan US Quercetin: A Promising Treatment for the Common Cold. 2014 J Anc Dis Prev Rem 2014, 2:2 http://dx.doi.org/10.4172/2329-8731.1000111