PT Unknown
AU Bremer, L
TI Functional characterization of NLRC3
PY 2014
PU Christian-Albrechts-Universität zu Kiel
WP https://macau.uni-kiel.de/receive/diss_mods_00014558
LA en
DE NLRC3; NLR; Inflammation; DSS; colitis; Entzündung; Kolitis
AB The innate immune system relies on several pattern recognition receptors (PRRs) to identify
pathogen associated molecular patterns (PAMPs). One of the most prominent non-clonal, germline
encoded but yet not fully characterized PRR group are the NOD-like receptors (NLRs). Here I aim
to characterize a hitherto rarely described member of the NLRs named NOD-like receptor CARD
domain containing 3 (NLRC3). Recent studies indicated, that NLRC3 is a cytosolic receptor which
negatively regulates T cell function.
This thesis utilizes several experimental approaches to access the cellular localization of NLRC3,
its functional interactions, and role in inflamed tissue. Microscopical studies showed, that NLRC3
is localized in the cytoplasm. Analysis of different organs indicated, that NLRC3 transcript level
are elevated in immune relevant tissues, but not in the intestinal tract. A Y2H screen indicated a potential
interaction with the mitochondrial protein IMMT/Mitofilin. Although a direct interaction
remained elusive, NLRC was detected in close spatial proximity of mitochondria via immunefluorescence
and identified in mitochondrial lysates. NLRC3 was found to interfere with NFB
signaling in a dose dependent manner. Dual luciferase assays were performed revealing connections
to TRAF6 and ERSE. NLRC3 seems to negatively regulate the TRAF6 mediated NFB
response. In combination with a potent stressor, such as tunicamycin elevates NLRC3 the ERSE
promoter activity. This reaction connects NLRC3 to cellular mechanisms of the unfolded protein
response, and subsequently to mitochondrial stress reactions. NLRC3 was found to be downregulated
in biopsies of WG patients. During this thesis Nlrc3+/+ and Nlrc3-/- mice were bred and utilized
in several experiments. Cytokine level in bone marrow derived macrophages varied between
Nlrc3+/+ and Nlrc3-/- in response to LPS stimulation. A DSS induced colitis was conducted and
revealed, that NLRC3 seems to be beneficial for survival and disease severity. These experiments
significantly enlarged the knowledge about NLRC3, pointing at the protective role of NLRC3
during cellular stress response and inflammation. NLRC3 is an important regulator in immune
modulation.
PI Kiel
ER