A Lysosome-Targeted Tetrazine for Organelle-Specific Click-to-Release Chemistry in Antigen Presenting Cells

Abstract

Bioorthogonal deprotections are readily used to control biological function in a cell-specific manner. To further improve the spatial resolution of these reactions, we here present a lysosome-targeted tetrazine for an organelle-specific deprotection reaction. We show that trans-cyclooctene deprotection with this reagent can be used to control the biological activity of ligands for invariant natural killer T cells in the lysosome to shed light on the processing pathway in antigen presenting cells. We then use the lysosome-targeted tetrazine to show that long peptide antigens used for CD8 + T cell activation do not pass through this organelle, suggesting a role for the earlier endosomal compartments for their processing.

Visible and Red Light-Triggered Anticancer Profile of a Ferrocene-Re(I)-Tricarbonyl Conjugate: Experimental and Theoretical Studies

“…The merged panel of MTR dye and ReFctp in Figure indicated the preferential mitochondrial localization of ReFctp with a Pearson’s correlation coefficient (PCC) value of 0.65. Furthermore, the localization of ReFctp in lysosome was determined with lysosome tracker red (LTR, lysosomal probe) . As shown in Figure S25, ReFctp displayed minimal lysosomal localization in A549 cells with a PCC value of 0.19.…”

“…Sadler and co-workers have also shown the light-triggered loss of MMP caused by Ir­(III) complexes, which demonstrated NADH photo-oxidation and mitochondrial localization. , In another report, the ferrocene conjugate of neodymium­(III) perturbed the mitochondrial activity upon light irradiation to induce apoptosis in HeLa cells . Furthermore, Re­(I) tricarbonyl complexes are also known to depolarize mitochondria to kill cancer cells. ,, For example, Wang et al . reported that mitochondria targeting dinuclear Re­(I) tricarbonyl complexes induced irreversible oxidative stress in HeLa cells by inducing mitochondrial dysfunction .…”

“…Furthermore, the localization of ReFctp in lysosome was determined with lysosome tracker red (LTR, lysosomal probe). 74 As shown in Figure S25, ReFctp displayed minimal lysosomal localization in A549 cells with a PCC value of 0.19. It has been observed that Re(I) tricarbonyl complexes are primarily localized in the nucleus or mitochondria of cancer cells.…”

“…80 Furthermore, Re(I) tricarbonyl complexes are also known to depolarize mitochondria to kill cancer cells. 18,47,74 For example, Wang et al reported that mitochondria targeting dinuclear Re(I) tricarbonyl complexes induced irreversible oxidative stress in HeLa cells by inducing mitochondrial dysfunction. 81 Therefore, the impact of ReFctp (2 μM) on the MMP of A549 cells was assessed by a JC-1 assay (Figure 8b).…”

Bioorthogonal Chemistry in Cellular Organelles

“…Antigen presentation is a complex process, and the specific roles of individual organelles within this process remain the subject of ongoing debate. Investigating the contribution of lysosomes in antigen presentation, van Kasteren et al developed a lysosome-targeted tetrazine probe to enable organelle-restricted activation of TCO-caged antigens [ 79 ]. Immune cell activation occurred only when the bioorthogonal deprotection reaction took place within the organelle.…”