Proteomics

Abstract

Abstract:The concept of using stem cells for cardiovascular repair holds great potential, but uncertainties in preclinical experiments must be addressed before their therapeutic application. Contemporary proteomic techniques can help to characterize cell preparations more thoroughly and identify some of the potential causes that may lead to a high failure rate in clinical trials. The first part of this review discusses the broader application of proteomics to stem cell research by providing an overview of the main proteomic technologies and how they might help the translation of stem cell therapy. The second part focuses on the controversy about endothelial progenitor cells (EPCs) and raises cautionary flags for marker assignment and assessment of cell purity. A proteomics-led approach in early outgrowth EPCs has already raised the awareness that markers used to define their endothelial potential may arise from an uptake of platelet proteins. A platelet microparticle-related transfer of endothelial characteristics to mononuclear cells can result in a misinterpretation of the assay. The necessity to perform counterstaining for platelet markers in this setting is not fully appreciated. Similarly, the presence of platelets and platelet microparticles is not taken into consideration when functional improvements are directly attributed to EPCs, whereas saline solutions or plain medium serve as controls. Thus, proteomics shed new light on the caveats of a common stem cell assay in cardiovascular research, which might explain some of the inconsistencies in the field. (Circ Res. 2011;108:499-511.)

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

“…23 However, it must be cautioned that some circulating endothelial progenitor cells assays are relatively nonspecific as proteomics has shown that platelet microparticles can cause the transfer of endothelial characteristics to mononuclear cells. 135 During ACS, it has been identified that there is differential mobilization of each of the 3 phenotypes of monocyte (Table 2), 136 but it has not yet been identified how this influences prognosis.…”

MicroRNAs in Vascular and Metabolic Disease

“…Different proteomics approaches can be employed as reviewed previously. 111 To minimize falsepositives, it is advisable to search for communalities of protein changes after transfection of the precursor as well as inhibition of the endogenous miRNAs. Using pulsed stable isotope labeling by amino acids in cell culture (pSILAC), newly synthesized proteins can be pulse-labeled with different isotopes of amino acids and readily discerned from preexisting proteins.…”

“…114 Generally, studies on APCs, previously referred to as endothelial progenitor cells, have to be interpreted with caution given that these early outgrowth cultures tend to be contaminated with platelets. 111,115,116 …”

Endothelial Seeding for Abdominal Aortic Aneurysms

“…15,16 Unlike late-outgrowth ECs, endothelial progenitor cells do not give rise to ECs. Instead, the definition of endothelial progenitor cell has been obscured by the uptake of platelet microparticles by monocytes/macrophages, 17,18 and the mechanisms for the in vivo improvements observed in preclinical models after endothelial progenitor cell administration remain elusive, with paracrine effects, rather than differentiation, being the most likely explanation. Similarly, the authors in the present study speculate that injected cells secrete paracrine factors that have the potential to modify the endogenous healing process.…”