Research
The
innate immune system is the first line of defense against pathogen
infection. Recognition of bacteria and viruses by the innate
immune system immediately activates a series of downstream events that
initiate antibacterial and antiviral responses and stimulate the
adaptive immune system against the target pathogen. Several
classes of pattern recognition receptors (PRRs) mediate the initial
detection of non-self molecules such as bacteria-specific membrane
components or viral nucleic acids. Correct recognition of
non-self molecules is important for the efficient immune response
against the target pathogen, whereas incorrect recognition of self
molecules can trigger an inappropriate response resulting in autoimmune
or inflammatory diseases such as type I diabetes, arthritis and
inflammatory bowel disease.
Our
lab focuses on the functions and mechanisms of several PRRs that
specifically recognize viral nucleic acids, such as several Toll like
receptors and RIG-I-like helicases. Understanding the function of
the nucleic-acid specific PRRs (naPRRs) presents a new challenge
compared to membrane specific PRRs because high concentrations of
structurally diverse host nucleic acids are ubiquitous throughout the
cellular environment. This raises the following questions:
1. What features of nucleic acids distinguish self from non-self?
2. How do naPRRs activate an immune response?
3. What role does the recognition of self nucleic acids play in autoimmune & inflammatory diseases?
To
address these questions our lab uses a multidisciplinary approach
including X-ray crystallography, computational simulation, biochemical
and biophysical methods in conjunction with various cell biology
techniques. Our short-term goal is to determine the structures,
dynamics and functions of naPRRs in isolation, in complex with nucleic
acids, and in higher order complexes with functional partners involved
in the signaling pathways. In parallel, we aim to identify &
characterize cellular nucleic acids that trigger naPRRs resulting in
activation of the immune response in tissues from patients with
autoimmune or inflammatory diseases, with the long-term goal of
determining the molecular mechanisms for disease pathogenesis. We
believe that understanding the mechanisms of naPRR regulation will
provide therapeutic strategies to treat inflammatory diseases as well
as to improve the antiviral immune response. In addition,
understanding the molecular mechanisms of nucleic acid specificity of
naPRRs will help us design new therapeutic nucleic acids (such as
siRNA) that do not evoke undesirable immune responses.