Proteomic Discovery and Array-Based Validation of Biomarkers from Urinary Exosome by Supramolecular Probe

Exosomes are nanoscale, membrane-enclosed
vesicles with contents
similar to their parent cells, which are rich in potential biomarkers.
Urine, as a noninvasive sampling body fluid, has the advantages of
being simple to collect, stable in protein, diverse and not regulated
by homeostatic mechanisms of the body, making it a favorable target
for studying tumor biomarkers. In this report, the urinary exosomal
proteome was analyzed and high-throughput downstream validation was
performed using a supramolecular probe-based capture and in
situ detection. The technology demonstrated the efficient
enrichment of exosomes with a high concentration (5.5 × 1010 particles/mL) and a high purity (2.607 × 1010 particles/mg) of exosomes from urine samples. Proteomic analysis
of urine samples from patients with hepatocellular carcinoma and healthy
individuals combined with proteomic screening techniques revealed
that 68 proteins were up-regulated in patients with hepatocellular
carcinoma. As a proof-of-principle study, three of these differentially
expressed proteins, including OLFM4, HDGF and GDF15, were validated
using the supramolecular probe-based array (48 samples per batch).
These findings demonstrate the great potential of this approach toward
a liquid biopsy for the discovery and validation of biomarkers from
urinary exosomes, and it can be extended to various biological samples
with lower content of exosomes.