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. 2013 Feb 1;3:1197. doi: 10.1038/srep01197

Figure 4. ADSC-derived exosomes possess enzymatically active NEP.

Figure 4

(A) Immunoblotting for NEP of exosomes isolated from ADSCs #1–4. (B–D) NEP enzyme activity assay for ADSC-derived exosomes (#1–4). NEP enzyme activity was measured using a fluorogenic peptide substrate, Mca-RPPGFSAFK(Dnp) and NEP inhibitor thiorphan. NEP specific activity (B) was calculated by subtracting the residual fluorescence intensity measured in the presence of thiorphan (D) from the total enzyme activity measured in the absence of thiorphan (C). Addition of thiorphan sharply reduced the enzyme activity of ADSC-derived exosomes (D). (E) NEP contribution ratio for ADSC-derived exosomes calculated as the percentage ratio of NEP-specific activity rate to total activity rate. (F) NEP-specific enzyme activity levels of exosome fractions of ADSCs #1–4 were estimated from a rhNEP standard curve (Fig. 4S) and are represented as the value ng-rhNEP/μg protein (termed as NEP activity index in the diagram). N.D. indicates “not determined”.