In vivo imaging methods for studying host-microbiota interactions
Szöllősi Dávid
Theoretical and Translational Medicine
Dr. Kellermayer Miklós
SE Neurológiai Klinika előadóterme
2024-11-04 15:00:00
Celluláris és molekuláris biofizika
Dr. Szigeti Krisztián
Dr. Pállinger Éva
Dr. Bóta Attila
Dr. Bereczki Dániel
Dr. Garay Tamás
Dr. Nardai Sándor
There is an ongoing effort to understand host-microbiota interactions and develop accurate diagnostic methods and treatment approaches for diseases involving microbiota. In my thesis I report the development of a radiolabeling technique that can be used to study the biodistribution of bacterial outer membrane vesicles (OMVs), which are important mediators in host-microbiota interactions. A genetically modified E. coli BL21(DE3) ΔLpxM, ΔnlpI was created to produce OMVs leveraging its hypervesiculating phenotype and decreased LPS immunogenicity. Different surface display systems, based on two autotransporters (Hbp and AIDA-I) were used to anchor SpyCatcher on the OMV surface. Radiolabeling with 64Cu was achieved using SpyTag-based bifunctional chelators containing the macrocyclic chelator NODAGA. HPLC analysis showed excellent radiochemical purity and serum stability. Positron emission tomography (PET) indicated that the radiolabeling is stable in vivo OMVs. I also report the evaluation of [123I]CLINME, a nuclear medicine imaging tracer in a murine model of sepsis-associated encephalopathy for the early detection of neuroinflammation in the model. Single photon emission computed tomography (SPECT) revealed that [123I]CLINME can show the increase in cerebral TSPO binding sites 5 h after the induction of systemic inflammation in mice. In conclusion, our results provide new possibilities for the in vivo imaging of different aspects of host-microbiota interactions. The modularity of our OMV radiolabeling technique provides great versatility and it can serve as a template for further imaging methods. Our results prove the usefulness of [123I]CLINME which can be used for both SPECT and PET imaging, allowing for more flexible experimental design and promote a wider availability of TSPO imaging in translational research in the future.
