A Bone Proteomic Approach to Body Decomposition for Forensic Investigations

Bone proteomic methods devised for fields such as archeology and paleontology have been implemented to resolve the challenge of accurate post-mortem interval (PMI), time of death, estimation in forensic investigations. However, most of these methods have been optimized to extract a large variety of proteins without taking into account the laboratory-induced decay and post-translational modifications (PTMs). Since PTMs can be used as markers of degradation, optimizing an extraction protocol that reduces laboratory-induced PTMs while increasing protein recovery is imperative to accurate results in forensic investigations. Procopio and Buckley assessed demineralization, protein denaturation, and digestion solvents and lengths and utilized an in-Stage Tip extraction for an optimized protocol specific to forensic PMI determination.¹ The protocol reduced laboratory-induced PTMs by decreasing the grating chemical and physical procedures that samples undergo in more typical bone protein extractions. This extraction method has been widely used in forensics since its publication, however, the In-Stage Tip technique used results in sample loss due to sample transfer between vessels and cannot solubilize some reagents that could be utilized in the sample preparation. A recent study sought to further optimize the Procopio and Buckley protocol in the protein denaturation step as well as utilizing suspension-trap extraction technology in which the extraction takes place in a single tube resulting in less sample loss.² These studies contribute to the development of a standardized proteomic workflow that uses liquid chromatography mass spectrometry (LC-MS/MS) for accurate PMI estimation.  

1. Procopio, N; Buckley, M. Minimizing Laboratory-Induced Decay in Bone Proteomics. J. Proteome Res. 2017, 16(2), 447-458, DOI: 10.1021/acs.jproteome.6b00564 
2. Gent, L; Chiappetta, M; Hesketh, S; Palmowski, P; Porter, A; Bonicelli, A; Schwalbe, E; Procopio, N. Bone Proetomics Method Optimization for Forensic Investigations. J. Proteome Res. 2024, 23(5), 1844-1854, DOI: 10.1021/acs.jproteome.4c00151