Centre for Research in Biomolecular Interactions presents Prof. Nades Palaniyar, Scientist, Physiology & Experimental Medicine, The Hospital For Sick Children, University of Toronto

Talk Title: NETs for catching bacteria: Infection, inflammation and tissue damage

Abstract:

Palaniyar lab has been studying the effects of “antibodies of the innate immune system” and neutrophil extrcellular traps (NETs). Large amounts of  ”anti-carbohydrate antibody-like”  collectins or collagenous lectins present in the lungs recognize the terminal carbohydrate moieties present on many bacterial pathogens including Pseudomonas aeruginosa and Staphylococcus aureus. Oligomeric collectins such as pulmonary surfactant-associated protein A and D (SP-A, SP-D) bind to microbial pathogens, agglutinate them and promote their clearance by phagocytes such as macrophages and neutrophils.  NETs are recently identified fibrous DNA-protein complexes that are released by neutrophils for effectively trapping and killing microbial pathogens extracellularly. Our studies show that collectins can regulate NETosis and microbial clearance. In the seminar, roles of collectins in influencing the type of immune cell death, bacterial clearance and damage to the infected tissue will be discussed.

Research Interests:

Palaniyar's lab aims i) to understand novel innate immune functions of SP-A and SP-D, and (ii) to determine the therapeutic potential of these proteins to treat infectious and inflammatory lung diseases.

Interestingly, while adults rely on both innate and antibody-based adaptive immune systems, neonates and children depend primarily on innate immune system for their protection against invading microbial pathogens. To better understand the innate immune system in the lungs, we study SP-A and SP-D. We consider these collections as the antibodies of the innate immune system.

SP-A and SP-D are innate immune collectins (collagenous lectins) that are secreted onto the inner airway surfaces. These proteins constitute about 90 per cent (w/w) of the proteins associated with lung surfactant lipid that covers the inner surface of the airways. These antibody-like innate immune pattern-recognition proteins recognize the carbohydrate arrays present on the inhaled microbes and particles. They form immune complexes to enhance the killing and clearance of foreign invaders from the lungs. SP-D specifically enhances the clearance of infectious agents, DNA and dying immune cells by macrophages. Our current studies suggest that SP-D may also enhance NET-mediated clearance of various infectious agents. SP-A and SP-D are destroyed by some pathogens and dysregulated during infection or in many lung diseases. We conduct research work to determine the molecular mechanisms regulated by these proteins.

Please join us,

Refreshments will be served.