Mass spectrometry-based serum peptidomic profiling reveals potential biomarker for canine hepatozoonosis.

Canine hepatozoonosis, caused by Hepatozoon canis, is a significant canine vector-borne disease (CVBD) with a complex life cycle and diverse clinical manifestations, ranging from asymptomatic to severe illness. While several diagnostic methods are available, no studies have yet applied serum peptidomic analysis to this disease. This study aimed to identify peptide mass fingerprints (PMFs), serum peptidome clusters, and potential biomarker peptides in infected dogs. Blood and serum samples were collected from two groups: H. canis-infected dogs (n = 15) and healthy controls (n = 20). Serum peptidome profiling was conducted using MALDI-TOF MS and LC-MS/MS, with data analyzed via MetaboAnalyst 6.0. Distinct PMFs from MALDI-TOF MS effectively distinguished between infected and control groups, revealing five potential peptide markers (m/z 2892.06, 2837.65, 2874.76, 1495.25, and 1423.79). LC-MS/MS identified 98 upregulated peptides in the infected group. Protein interaction analysis highlighted TNS1, ZEB2, and mTOR, suggesting links to potential therapeutic targets. This is the first study to apply a peptidomic approach to canine hepatozoonosis, demonstrating its value in identifying novel biomarker panels and offering a promising diagnostic tool for improved disease detection.