Paleoproteomic study of the Iceman’s brain tissue

Abstract

The Tyrolean Iceman, a Copper-age ice mummy, is one of the best-studied human individuals. While the genome of the Iceman has largely been decoded, tissue-specific proteomes have not yet been investigated. We studied the proteome of two distinct brain samples using gel-based and liquid chromatography-mass spectrometry-based proteomics technologies together with a multiple-databases and -search algorithms-driven data-analysis approach. Thereby, we identified a total of 502 different proteins. Of these, 41 proteins are known to be highly abundant in brain tissue and 9 are even specifically expressed in the brain. Furthermore, we found 10 proteins related to blood and coagulation. An enrichment analysis revealed a significant accumulation of proteins related to stress response and wound healing. Together with atomic force microscope scans, indicating clustered blood cells, our data reopens former discussions about a possible injury of the Iceman's head near the site where the tissue samples have been extracted.

A guide to ancient protein studies

“…The advent of high-sensitivity mass spectrometry in the past two decades has allowed palaeoproteomics to become increasingly relevant in the fields of archaeology and evolutionary biology. Not only can individual proteins from archaeological and palaeontological contexts be studied, but one can also analyse the complex mixtures of proteins produced by individual organisms (proteomes) or groups of organisms (metaproteomes) found within ancient samples 1-3 . This has facilitated the phylogenetic reconstruction of extant and extinct species 2,[4][5][6] , including that of hominins 7 , the mechanistic investigation of protein degradation pathways 8 , studies of diagenetic and in vivo protein post-translational modifications (PTMs) [9][10][11] , the reconstruction of human diet and subsistence patterns 3,12 , and the characterization of past human diseases 3,[13][14][15][16] . The range of tissues and substrates that can be analyzed is similarly broad, including bone, antler, dentine and enamel 1,7,[17][18][19] , eggshell 8,20 , skin and soft tissues 13,14 , dental calculus 21 , preserved food remains [22][23][24][25] , potsherds and ceramic vessels [26][27][28] , bindings and glues [28][29][30][31] , paint binders [32][33]…”

Paleoproteomics of the Dental Pulp: The plague paradigm

“…This expands the spectrum of retrievable inflammatory proteins previously generated by the paleoproteomic analysis of the human dental calculus [35]. Obviously, the dental calculus and the dental pulp were readily available contrary to brain tissue in which proteins had been previously analyzed in the Tyrolean Iceman [36]. The fact that immunoglobulins have been easily detected in ancient dental pulp suggests that studying ancient dental pulp proteome may give information on both the pathogen and the host inflammatory response and be used for direct and indirect serological diagnoses.…”

Preserved brain of the Woolly mammoth (Mammuthus primigenius (Blumenbach 1799)) from the Yakutian permafrost

“…There are also bog bodies, and several unique freeze-dried mummies are known (Aufderheide, 2003;Lynnerup, 2007). Preserved brain structures are very rare even among numerous findings of these naturally mummified human remains (Tkocz et al, 1979;Radanov et al, 1992;Gerszten and Martinez, 1995;Previgliano et al, 2003;Eklektos et al, 2006;Kim et al, 2008;Maixner et al, 2013). All this findings are much younger than the current specimen (39,440e38,850 cal BP).…”