To better understand how early events lead to severe liver disease and to compare differences in gene-expression patterns over time within each individual selleckchem disease group, we performed a longitudinal kinetic analysis.

We used a recently utilized classifier7 derived from the analysis of many different longitudinal, publicly available and in-house datasets using Kohonen maps approach, which fits gene expression to topographic maps representing distinct regulatory patterns. Our classifier comprised relevant topographic groups: g1- 6 for initial positive regulation; a neutral g0 group for genes expressed but unchanged; and the mirror g-1-g-6 groups for negative regulation (Fig. 3A). The classifier tests for statistical significance (i.e., fold-change–based z test) of association with individual topographic groups by testing the statistical significance of the logarithmic fold-change difference in expression of every individual gene at every time

point against its estimated baseline, with absolute expression change rescaled to unity. Thus, gene expression was analyzed for its characteristic, statistically significant “shape” over time, rather than magnitude of change. We further subdivided the time categories to generate a fourth category (Fig. 1B). Because we were mainly interested click here in identifying genes involved in severe liver disease development, we focused on genes that permanently change expression over time (Fig. 3B; Supporting Table 2). Using IPA, we categorized 48 genes related to inflammatory responses selleck chemical and immune cell trafficking, particularly phagocyte and lymphocyte recruitment and chemotaxis, including many C-X-C and C-C chemokines and chemokine receptors. Also, we observed molecules bridging innate and adaptive immune

functions, including signal transduction and activation of immune and inflammatory transcriptional responses, proinflammatory cytokines, Fc receptors, complement components, ISGs, HLA alleles, and lymphocyte activation. We also identified increases in genes associated with HSC activation and COL deposition, including TIMP metalloproteinase inhibitor, LGALS3, and multiple COL transcripts. Finally, 59 genes associated with cancer also gradually increased, including many associated with metastasis, cell proliferation, and cell death, indicating that dysregulation of normal cell division and apoptotic mechanisms underlie hepatic inflammation and COL deposition. We also evaluated the functional significance of DEG down-regulated over time after OLT. We identified 12 genes associated with lipid, drug, vitamin and mineral, and carbohydrate metabolism. These are involved in lipid biosynthesis, fatty acid oxidation, and amino acid and glucose metabolism. G345 patients therefore demonstrated reduced hepatic metabolic function, consistent with reductions in metabolic activity previously observed at late time points in HCV-infected hepatic cells in vitro.