DNAJB6-Containing Extracellular Vesicles as Chaperone Delivery Systems: A Proteomic Analysis

Abstract

Cell-derived extracellular vesicles (EVs) are effectors of cell-to-cell communication that are in the spotlight as promising candidates for in vivo drug delivery because of their ability to enter cells and deliver cargo. For example, proteins of interest can be loaded into EVs to mediate protein transfer into target cells. To determine causality between EV content and function, which is also important to assess the clinical safety of EVs, it is crucial to comprehensively characterize their complete molecular composition. Here, we investigated EVs loaded with the chaperone protein DNAJB6. Chaperone proteins assist in protein folding and have been suggested to alleviate protein aggregation diseases, such as Alzheimer’s disease and Huntington’s disease. We analyzed and compared the proteome of EVs isolated from wildtype HEK293T cells with that of EVs from HEK 293T cells overexpressing DNAJB6-WT or loss-of-function mutant DNAJB6-M3. Comprehensive analysis of proteomics data showed enhanced levels of DNAJB6 as well as protein-folding-related proteins in EVs derived from DNAJB6-overexpression cells. Interestingly, upregulation of a chaperone and its protein-folding-related proteins resulted in downregulation of another chaperone plus its related proteins, and vice versa. This implies the presence of compensatory mechanisms in the cellular expression of chaperones. Collectively, we provide the proteomic EV signatures underlying EV mediated DNAJB6 transmission by HEK293T cells, with the aim of establishing a causal relationship between EV protein content and EV function.

Proteomic Research of Extracellular Vesicles in Clinical Biofluid

“…After protein co-expression network analysis in human brain-derived EVs, they found EVs derived from astrocytes are the most significant enrichment module and highlighted the potential pathogenesis mechanism in AD. Additionally, promising and novel AD biomarkers of EVs derived from various sources were discovered [ 61 , 62 , 63 , 64 , 65 , 66 , 67 ], and researchers compared the proteomic landscape following the knockout or overexpression of important genes to understand AD pathology [ 68 , 69 ]. Jewett et al [ 70 ] revealed the dysregulated protein of EVs isolated from the Gba1b mutant (GBA deficiency) Drosophila model to promote abnormal protein aggregation in neurons of PD.…”