Strategies for understanding dynamic, personalized profiles of host-derived proteins and microbes from human stool

Abstract

265 words) 25 Measuring host proteins through noninvasive stool-based assays opens new avenues 26 for characterizing states of gastrointestinal health. However, the extent to which these 27 proteins vary over time and between healthy subjects is poorly characterized. Here, we 28 characterize technical and biological sources of variability in mass spectrometry-based 29 measurements of host proteins in stool. We identify the proteins that most vary over 30 time within an individual, and among different individuals. Finally, we examine and 31 compare temporal and inter-individual variation in host protein and bacterial taxonomic 32 profiles of the same fecal specimens. To address these issues, five self-reported 33 healthy individuals were each sampled eight times over four weeks. First, we 34 demonstrate that mass spectrometry-based identification and label-free quantification of 35 stool proteins exhibit non-significant variability (p>0.05) between both technical and 36 preparative replicates for a subset of 78 proteins, supporting the utility of this method for 37 biomarker measurement. Second, although 13 human stool proteins varied significantly 38 in relative abundance over time within individuals, 58 proteins varied significantly (at 39 least four-fold) between subjects. The average pair-wise difference between individuals 40 was greater than the average within-subject difference for both the proteome and 41 microbiome datasets (p<0.0001). Fecal host proteins, like the traditional fecal protein 42 marker, calprotectin, unambiguously pointed to innate and adaptive immune responses. 43For example, one subject's fecal protein profile suggested a sub-clinical inflammatory 44 state. From these data, we conclude that host-centric protein measurements in stool 45 reveal a wide range of variation during states of apparent health, and add a valuable 46 complementary insight into host-microbiota relationships. 47 IMPORTANCE 48Human proteins in stool hold untapped potential for characterizing gastrointestinal 49 health. To fully harness this potential and create a baseline of healthy stool protein 50 abundances and identifications, it will be important to establish the extent to which these 51 proteins might vary in the absence of disease. This study quantifies the major sources 52 of variation in stool protein abundance data. We assessed technical, preparative, 53 temporal, and inter-subject variability of human protein abundances in stool and found 54 3 that among these sources, differences between subjects accounted for the greatest 55 amount of variation, followed by temporal differences, and then technical factors. Our 56 paired microbiome analysis found matching patterns of temporal and inter-subject 57 variability. By characterizing multiple variance parameters in host stool protein 58 abundances, our analysis helps to contextualize a wide range of future disease-focused 59 stool studies as well as elucidate host-microbe interactions. 60 61 4 1. Introduction 62The expression of host proteins in the human ga...

StoolNet for Color Classification of Stool Medical Images

“…Some researchers have studied human stools based on biotechnology [4]. However, an accurate automatic analysis system for stool color based on computer technologies is still absent [5].…”