Application of Large Scale Aptamer-Based Proteomic Profiling to "Planned" Myocardial Infarctions
Background—Emerging proteomic technologies using novel affinity-based reagents allow for efficient multiplexing with high sample throughput. To identify early biomarkers of myocardial injury, we recently applied an aptamer-based proteomic profiling platform that measures 1,129 proteins to samples from patients undergoing septal alcohol ablation for hypertrophic cardiomyopathy, a human model of "planned myocardial injury" (PMI). Here we examined the scalability of this approach using a markedly expanded platform to study a far broader range of human proteins in the context of myocardial injury.
Methods—We applied a highly multiplexed, expanded proteomic technique that uses single stranded DNA aptamers to assay 4,783 human proteins (4,137 distinct human gene targets) to derivation and validation cohorts of PMI, to individuals with spontaneous myocardial infarction (SMI), and to at-risk controls.
Results—We found 376 target proteins that significantly changed in the blood after PMI in a derivation cohort (n=20; P < 1.05E-05, one-way repeated measures ANOVA, Bonferroni- threshold). Two hundred forty-seven of these proteins were validated in an independent PMI cohort (n=15; P < 1.33E-04, one-way repeated measures ANOVA); > 90% were directionally consistent and reached nominal significance in the validation cohort. Among the validated proteins that were increased within 1 hour after PMI, 29 were also elevated in patients with spontaneous myocardial infarction (n=63; P < 6.17E-04). Many of the novel markers identified in our study are intracellular proteins not previously identified in the peripheral circulation or have functional roles relevant to myocardial injury. For example, the cardiac LIM protein cysteine and glycine-rich protein 3 (CSRP3) is thought to mediate cardiac mechanotransduction and stress responses while the mitochondrial ATP synthase F0 subunit component (ATP5J) is a vasoactive peptide upon its release from cells. Finally, we performed aptamer-affinity enrichment coupled with mass spectrometry to technically verify aptamer specify for a subset of the new biomarkers.
Conclusions—Our results demonstrate the feasibility of large scale aptamer multiplexing at a level that has not previously been reported and with sample throughput that greatly exceeds other existing proteomic methods. The expanded aptamer-based proteomic platform provides a unique opportunity for biomarker and pathway discovery following myocardial injury.
- Received May 11, 2017.
- Revision received October 26, 2017.
- Accepted November 8, 2017.