Serum Proteomics Profiling in Newborns: Differences Compared to Adults serum and new molecular panel for neonatal Sepsis

Abstract

Abstract Background Neonatal sepsis is a major cause of morbidity and mortality, particularly in low- and middle-income countries such as Senegal, where incidence is 78–104 per 1,000 live births and mortality exceeds 20 per 1,000, with case fatality rates around 36%. Diagnosis is difficult due to non-specific clinical signs and lack of molecular biomarkers, highlighting the need for improved early diagnostic molecular panel that could be applied even outside hospital settings. Objectives Compare neonatal and adult serum proteomes to establish a reference and identify serum protein biomarkers of neonatal sepsis. Methods Serum samples from Senegalese neonates and adults were analyzed using data-independent acquisition (DIA) proteomics on neat serum (Evosep-timsTOF HT platform). The cohort comprised 22 with confirmed sepsis (CS), 6 neonates with non-confirmed sepsis (NCS), 17 healthy newborn controls (HC), 6 unclassified and 20 healthy adults. Downstream analyses included differential protein abundance testing, unsupervised clustering, weighted gene co-expression network analysis (WGCNA), and correlation analyses with clinical parameters. Results We identified 979±20 proteins in newborns versus 718±40 in adults. Newborns showed reduced immune-response related proteins, a narrower dynamic range, and increased structural proteins such as collagens, consistent with immune immaturity and tissue development. Unsupervised WGCNA analysis led to a 53-protein cluster discriminated CS from NCS/HC. Some of these dysregulated proteins identified have already been reported in independent studies using different approaches in neonatal and/or adult sepsis. Our larger panel however of identified markers maps to three major biological processes involved in sepsis: (i) pathogen sensing (LBP, CD14), and acute-phase inflammation (e.g. CRP, SAA1/2, ORM1/2); (ii) innate immune activation and leukocyte recruitment (e.g., FCGR3A, CSF1R, CD163, CD206) and final platelet exhaustion, (e.g., PF4, PPBP, THBS1, GP5); (iii) endothelial injury and microvascular dysfunction with tissue remodeling (e.g., ICAM1, VCAM1, VWF, SPARC) with simultaneous loss of protective lipoproteins and serpins (e.g., APOA1, APOA2, APOM, SERPINA4, SERPINA5) Conclusion This study provides a very comprehensive neonatal serum proteome characterization and identifies a protein panel of proteins mapped to three major processes in sepsis.