Fig 1.
Study outline showing the subject groups and the methodological approach.
Proteomic data were obtained from the pooled and purified serum samples of patients with compensated advanced chronic liver disease (cACLD), divided in two groups related to the presence of clinically significant portal hypertension. Created with BioRender.com. Abbreviations: cACLD = compensated advanced chronic liver disease; HVPG–Hepatic venous pressure gradient.
Table 1.
Characteristics of patients involved in the study.
Fig 2.
Quantitative Venn diagram of proteins expressed in sera of patients with clinically significant portal hypertension (CSPH) and non-CSPH group.
Red and green arrows denote proteins that were respectively upregulated and downregulated in CSPH (> 2-fold increase/decrease in intensity levels), whereas black line depicts no, or less than 2-fold change in intensity. Black boxes highlight identified proteins with plausible pathophysiological role in PH development among those identified (A) solely in CSPH group, (B) solely in non-CSPH group, and (C) represented in both groups but with >2-fold higher intensity in CSPH group. Abbreviations: ATX–Autotaxin; BPI–Bactericidal permeability increasing protein; CAT–Catalase; CD44 –Cluster of differentiation 44; FN1 –Fibronectin; HIST1H2BN–Histone H2B; HIST1H4A –Histone H4; LYVE1 –Lymphatic vessel endothelial hyaluronic acid receptor 1; MPO–Myeloperoxidase; NPNT–Nephronectin; PAI-1 –Plasminogen activator inhibitor 1; PRDX2 –Peroxiredoxin-2; S100-A9—Protein S100-A9.
Table 2.
Proteins identified as potential candidate biomarkers for CSPH.
Proteins selected by manual curation based on their plausible role in the pathogenesis of portal hypertension.
Fig 3.
Proteins present both in patients with CSPH and no CSPH, identified with the highest fold-increase in their relative intensity levels in the sera of CSPH (A) and non-CSPH patients (B). Abbreviations: ANXA2 –Annexin A2; APOC4 –Apolipoprotein C-IV; FLNA–Filamin-A; HIST1H1B –Histone H1.5; HIST1H1E –Histone H1.4;Histone H1.3; IGF-I–Insulin-like growth factor 1; IGHV4-4 –Immunoglobulin heavy variable 4–4; ITGA2B –Integrin alpha-Iib; JUP–Junction plakoglobin; LCAT–Phosphatidylcholine-sterol acyltransferase; F13A1 –Coagulation factor XIII A chain; FAM20C –Extracellular serine/threonine protein kinase; FST–Follistatin; RWDD1 –RWD domain-containing protein 1; S100-A8 –Protein S100-A8; S100-A9 –Protein S100-A9; SAA2-SAA4 –Serum amyloid A-4 protein; SSC5D –Soluble scavenger receptor cysteine-rich domain-containing protein; STXBP5 –Syntaxin-binding protein 5.
Fig 4.
Interaction network of protein cluster identified exclusively in clinically significant portal hypertension (CSPH), and proteins >2-fold upregulated in sera of CSPH vs non-CSPH patients.
Line thickness indicates the strength of data support. Proteins with interaction score under 0.7 (designating low and medium confidence interactions) and disconnected nodes are excluded from the network. Functional enrichment analysis reveals the most significant (i.e. with the highest strength and lowest false discovery rate) biological process (red nodes), KEGG pathways (blue nodes) and tissue expression patterns (green nodes) of the depicted proteins. Abbreviations: CD44 –Cluster of differentiation 44; CHL1 –Close homolog of L1; COL-(1A1,1A2, 5A2, 6A3)–Collagen subtypes; FCGR3A –Low affinity immunoglobulin gamma Fc region receptor III-A; IGF-I–Insulin-like growth factor 1; IGFBP7 –Insulin-like growth factor-binding protein 7; KEGG–Kyoto Encyclopedia of Genes and Genomes; LYVE1 –Lymphatic vessel endothelial hyaluronic acid receptor 1; MMP2–72 kDa type IV collagenase; PPIB–Peptidyl-prolyl cis-trans isomerase B; PTPRS–Receptor-type tyrosine-protein phosphatase S; S100-(A8, A9, A12)–Protein S100 –(A8, A9, A12); SELL–L-selectin; SERPINE1 –Plasminogen activator inhibitor 1.
Fig 5.
Functional enrichment depicting the biological processes associated to the proteins detected in the sera of clinically significant portal hypertension (CSPH) and non-CSPH patients, listed from smallest to largest ratio (percentage) of proteins related to the respective process.
X-axis: Percentage of detected proteins associated to a specific biological process, Y-axis: Biological process identified by functional enrichment. Abbreviations: CSPH = clinically significant portal hypertension.
Fig 6.
Overview of the proteins identified in patients with CSPH and their proposed role in pathogenesis and progression of PH in cACLD.
1. Gut bacterial products, immune complexes, and platelets trigger the formation of NET, which promote sinusoidal damage and microthrombosis supported by PAI-1 from activated endothelium. 2. Damage to LSEC leads to increased HA production which in turn increases CD44 mediated neutrophil sequestration, perpetuates inflammation and HSC activation. 3. ATX and NPNT influence HSC activation, contractility and fibrogenesis. 4. VEGF-C from macrophages, LYVE-1, CD44 and TN-C induce lymphangiogensis. Abbreviations: AHSC–activated hepatic stellate cell; ATX–Autotaxin; BPI—Bactericidal permeability increasing protein; cACLD—Compensated advanced chronic liver disease; CD44—Cluster of differentiation 44; CSPH—Clinically significant portal hypertension; HA—Hyaluronic acid; INT–Integrin; KC—Kupffer cells; LEC–lymph vessel endothelial cell; LPA- Lysophosphatidic acid; LPS–Lipopolysaccharide; LYVE1—Lymphatic vessel endothelial hyaluronic acid receptor 1; MP–Macrophage; MPO–Myeloperoxidase; NET–Neutrophil extracellular traps; NPNT–Nephronectin; PAI-1—Plasminogen activator inhibitor 1; PH—Portal hypertension; QHSC–quiescent hepatic stellate cell; rLPA—Lysophosphatidic acid receptor; ROS—Reactive oxygen species; TN-C—Tenascin C; VEGFR3 –Vascular endothelial growth factor receptor 3.