PRIN 2022 Scorrimento - Prot. 2022Y9LK8T

A dysfunctional microbiota-host communication leads to intestinal chronic inflammation and promotes cancer in genetically susceptible individuals. The L503F (1672t) allele of the organic cation transporter novel 1 OCTN1/Slc22A4 has been linked to Inflammatory Bowel Disease (IBD) and more recently to colitis-associated cancer, but evidence for this gene variant being disease causal, and the mechanistic underpinnings, have remained elusive. As a carrier protein abundantly expressed in immune cells OCTN1 likely participates in host-microbe cross-talks at the intestinal barrier. Accordingly, our preliminary data show that monocytes from healthy carriers of the 503F variant display an enhanced Interleukin 1 beta response to the bacterial wall component peptidoglycan (PGN) compared to control subjects; moreover, OCTN1 forms a complex with NOD2, an immune receptor for PGN fragments. We’ll elaborate on these important observations to demonstrate that OCTN1 variants, by altering microbial detection by mucosal inflammatory cells, play a causative role in IBD, with far-reaching clinical implications for the targeted prevention and therapy of these important diseases. Our multidisciplinary team will pursue two specific aims: a) To dissect signaling roles OCTN1 and its 503F variant in the pro-inflammatory/immune responses elicited by bacteria and their associated molecular patterns (MAPS) in monocytes. We’ll use a combination of biomolecular, microbiological and confocal imaging studies to address how OCTN1 genotype and expression level affect cytokine responses and microbial killing in monocytes exposed to MAMPs, or infected with selected bacterial strains. Searching for a molecular link between OCTN1 and specific immune cascades, we’ll also evaluate OCTN1's physical interaction with the bacterial sensor NOD2 and other intracellular immune receptors. b) To identify novel bacterial substrates for OCTN1 in PGN hydrolysates or bacteria-conditioned supernatants by a novel methodology based on substrate trapping in artificial proteoliposomes followed by Mass Specrometry identification. The project will be completed, through the coordinated effort of three research units,(UniCatt, U1; UniCal, U2; UniCT, U3) in two years. UniCatt will coordinatethe research activities through the organization of bimonthly meetings to discuss the progresses and remodulate experimental activities, in case of scientific issues. Additionally specific meetings will be set up to coordinate administrative duties related to the project activity. A dissemination plan is established to deliver results in dedicated scientific venues as well as in non-scientific ones via public engagement activities. Among the most relevant expected outcomes, there are: the advancements of knowledge at TLR1 level (as predicted by the PNRR plan) and the implementation of novel methodologies that could be amenable of technological transfer.

Working group:

• Giovambattista Pani - Responsabile scientifico UCSC

Partners:

• Università della Calabria
• Università degli Studi di Catania