Project description:The growing appreciation of immune cell-cell interactions within disease environments has led to significant efforts to develop highly effective protein-, and cell-based immunotherapies. However, characterizing these complex cell-cell interactions in high resolution remains challenging. Thus, technologies that leverage therapeutic-based modalities for profiling intercellular environments can provide unique advantages towards understanding these cellular interactions at molecular-level detail. To address this, we introduce photocatalytic cell tagging (PhoTag), a platform for profiling cell-cell interactions that utilizes a single domain antibody (VHH) conjugated to a photoactivatable flavin-based cofactor. Upon irradiation with visible light, the tethered flavin photocatalyst generates phenoxy radical tags for targeted labeling within cell-cell contact environments. Using anti-PD-1 or anti-PD-L1 VHH flavin conjugates, we demonstrate that PhoTag achieves highly selective synaptic labeling in antigen presenting cell-T cell co-culture systems. By combining the high resolution transcellular biotinylation capability of PhoTag with multi-omics single cell sequencing, we interrogated transient interactions between Peripheral blood mononuclear cell (PBMC) populations and Raji PD-L1 B cells and discovered that specific T cell subtypes can transiently interact more efficiently than others. We envision that the spatio-temporal and modular nature of PhoTag will enable its broad utilization for detailed profiling of intercellular interactions across different biological systems.
Project description:The growing appreciation of immune cell-cell interactions within disease environments has led to significant efforts to develop highly effective protein- and cell-based immunotherapies. However, characterizing these complex cell-cell interfaces in high resolution remains challenging. Thus, technologies that can leverage therapeutic-based modalities to profile intercellular environments offer the opportunity to study cell-cell interactions with molecular-level insight. To address this, we introduce Photocatalytic Cell Tagging (PhoTag), a platform for profiling cell-cell interactions utilizing a single domain antibody (VHH) conjugated to a photoactivatable flavin-based cofactor. Upon irradiation with visible light, the tethered flavin photocatalyst generates phenoxy radical tags for targeted labeling within cell-cell contact regions. Using anti-PD-1 or anti-PD-L1 VHH flavin conjugates, we demonstrate that PhoTag achieves highly selective synaptic labeling in antigen presenting cell-T cell co-culture systems. By combining the high resolution transcellular biotinylation capability of PhoTag with multi-omics single cell sequencing, we interrogated transient interactions between peripheral blood mononuclear cell (PBMC) populations and Raji PD-L1 B cells and discovered that specific T cell subtypes can transiently interact more efficiently than others. We envision that the spatiotemporal and modular nature of PhoTag will enable its broad utilization for detailed profiling of intercellular interactions across different biological systems.
Project description:we have developed a new catalytic tagging system and have used it on the identification of interacting partners of membrane proteins
Project description:Interventions: CTC and optical colonoscopy
Primary outcome(s): Low dose polyethylene glycol (PEG) based fecal tagging CTC vs. optical colonoscopy. Detection performance and accuracy of colorectal polyps (at least 6 mm in diameter) and colorectal cancer.
Study Design: Single arm Non-randomized
Project description:Microproteins are peptides and small proteins encoded by small open reading frames (smORFs). Newer technologies have led to the recent discovery of hundreds to thousands of new microproteins. The biological functions of a few microproteins have been elucidated, and these microproteins have fundamental roles in biology ranging from limb development to muscle function, highlighting the value of characterizing these molecules. The identification of microprotein-protein interactions (MPIs) has proven to be a successful approach to the functional characterization of these genes; however, traditional immunoprecipitation methods result in the enrichment of nonspecific interactions for microproteins. Here, we test and apply an in situ proximity tagging method that relies on an engineered ascorbate peroxidase 2 (APEX) to elucidate MPIs. The results demonstrate that APEX tagging is superior to traditional immunoprecipitation methods for microproteins. Furthermore, the application of APEX tagging to an uncharacterized microprotein called C11orf98 revealed that this microprotein interacts with nucleolar proteins nucleophosmin and nucleolin, demonstrating the ability of this approach to identify novel hypothesis-generating MPIs.