Abstract
Domestic dogs share the same environment as humans, and they represent a valuable animal model to study naturally-occurring human disease. Platelet proteomics holds promise for the discovery of biomarkers that capture the contribution of platelets to the pathophysiology of many disease states, however, canine platelet proteomic studies are lacking. Our study objectives were to establish a protocol for proteomic identification and quantification of the thrombin-activated canine platelet secretome (CAPS), and to compare the CAPS proteins to human and murine platelet proteomic data. Washed platelets were isolated from healthy dogs, and stimulated with saline (control) or gamma-thrombin (releasate). Proteins were separated by SDS-page, trypsin-digested and analyzed by liquid chromatography and tandem mass spectrometry (MS). CAPS proteins were defined as those with a MS1-abundance ratio of two or more for releasate vs. unstimulated saline control. A total of 1,918 proteins were identified, with 908 proteins common to all dogs and 693 characterized as CAPS proteins. CAPS proteins were similar to human and murine platelet secretomes and were highly represented in hemostatic pathways. Differences unique to CAPS included replacement of platelet factor 4 with other cleavage products of platelet basic protein (e.g. interleukin-8), novel proteins (e.g. C-C motif chemokine 14), and proteins in relatively high (e.g. protease nexin-1) or low (e.g. von Willebrand factor) abundance. This study establishes the first in-depth platelet releasate proteome from healthy dogs with a reference database of 693 CAPS proteins. Similarities between CAPS and the human secretome confirm the utility of dogs as translational models of human disease, but we also identify differences unique to canine platelets. Our findings provide a resource for further investigations into disease-related CAPS profiles, and for comparative pathway analyses of platelet activation among species.
Highlights
Comparative studies provide insight into platelet structure, function, and signaling pathways
In addition to many similarities between dogs and humans, we found several interspecies differences, including a subset of proteins that can be grouped into chemokines/cytokines, immunoglobulins, growth factors and proteins involved in lipid metabolism (Table 2)
Our study examined the response to thrombin, a physiologic platelet agonist, and identified canine platelet secretome (CAPS) proteins based on comparisons with paired unstimulated control samples
Summary
Acid citrate dextrose (ACD-A) anticoagulated whole blood samples (18 mL) were obtained from the cephalic vein of three healthy dogs as previously detailed [5]. One dog was a client-owned 5-year-old mixed breed spayed female and the other two dogs were a 6-year-old castrated male hound and a 3-year-old intact male beagle housed at an American Association for Accreditation of Laboratory Animal Care-approved facility. To account for the smaller body size and blood volume of dogs, the sample volume collected was less than used in human studies [24, 25, 29].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
