FIGURE 4.

Proteins from systemically administered ^MetRS*MSC-Exos can be detected, identified, and quantified in mouse organs via click-catalyzed alkyne-agarose capture. ^MetRS*MSC-Exos were injected into the tail vein of mice. Animals were euthanized 24 h later, and protein extracts were prepared from the heart, kidney, spleen, lung, liver, and brain; then, proteins from the ^MetRS*MSC-Exos (i.e., those containing the ANL label) were isolated via click-catalyzed alkyne-agarose capture and identified via LC-MS. (A) ^MetRS*MSC exosomal proteins isolated from the indicated organs (average total spectra) were presented as a heat map. (B) The abundance of canonical positive and negative exosome marker proteins was quantified in ^MetRS*MSC-Exos before injection (left) and in the indicated organs of mice after ^MetRS*MSC-Exo injection (right).