PGK1 modulates balance between pro- and anti-inflammatory cytokines by interacting with ITI-H4

Serum proteomic analysis identified ITIH4 as a potential novel biomarker for feline infectious peritonitis

Feline infectious peritonitis (FIP) is a fatal feline disease. At present, the reference standard for FIP diagnosis is immunohistochemistry (IHC) of organs, but this method involves high time-related costs, invasive sampling procedures and professional requirements. Serological detection is a common auxiliary method for diagnosing diseases. As a result, we assessed the changes in the serum proteome of FIP patients with the aim of identifying novel specific serum biomarkers that could aid in the clinical diagnosis of FIP. Pre- and postinfection groups were compared and 92 differentially expressed proteins (DEPs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the DEPs revealed that the enriched GO terms and KEGG pathways among the DEPs were immune activation, peptidase regulator activity and the complement and coagulation cascade pathways. The level of peptidase regulator interalpha-trypsin inhibitor heavy chain 4 (ITIH4) in cat serum was significantly correlated with FIP. The areas under the ROC curve (AUCs) of full-length ITIH4 (f-ITIH4) and cleaved ITIH4 (c-ITIH4) expression were 0.922 and 1.000, respectively, which allowed the discrimination of FIP cats from healthy cats. These results suggest that ITIH4 may be a potential serum biomarker for detecting early FIP. SIGNIFICANCE: FIP causes fatal disease in cats of almost all ages, and there is currently no effective vaccine or treatment for FIP. Therefore, early diagnosis is extremely important for disease prevention and control. The results of the model and clinical samples revealed that ITIH4 was significantly increased in the serum of FIP cats. This study is the first to propose ITIH4 as a diagnostic biomarker in cats with FIP and our results suggest that serum ITIH4 levels might identify cats with FIP during the early stage.

Effects of PGK1 on immunoinfiltration by integrated single-cell and bulk RNA-sequencing analysis in sepsis

Background

Sepsis, a life-threatening organ dysfunction caused by a dysregulated immune response to infection, remains a significant global health challenge. Phosphoglycerate kinase 1 (PGK1) has been implicated in regulating inflammation and immune cell infiltration in inflammatory conditions. However, the role of PGK1 in sepsis remains largely unexplored.

Methods

Four microarray datasets and a high throughput sequencing dataset were acquired from GEO database to reveal the PGK1 expression in patients of sepsis. Quantitative real-time PCR and western blotting was then used to validate the PGK1 level. Additionally, microarray and single-cell RNA sequencing data integration, including gene set enrichment analysis (GSEA), KEGG and GO functional enrichment analysis, immune infiltration analysis, and single-cell sequencing analysis, were performed to elucidate the role of PGK1 in sepsis.

Results

Our results revealed a significant upregulation of PGK1 in sepsis patients, with the area under the ROC curve (AUC) exceeding 0.9 across multiple datasets, indicating PGK1's strong potential as a diagnostic biomarker. Notably, PGK1 was enriched in key immune-related pathways, including the TNF signaling pathways, and leukocyte transendothelial migration, suggesting its involvement in immune regulation. Furthermore, PGK1 expression showed a positive correlation with the levels of inflammatory mediators CXCL1, CXCL16, and the chemokine receptor CCR1. In terms of immune cell infiltration, PGK1 was positively correlated with naive B cells, resting memory CD4 T cell, gamma delta T cells, M0 macrophages, eosinophils and negatively correlated with plasma cells, CD8 T cells, activated memory CD4 T cell, Tregs, activated dendritic cells.

Conclusions

This study concluded that PGK1 served as a novel diagnostic biomarker for sepsis, with potential implications for prognosis and immune regulation. The significant upregulation of PGK1 in sepsis patients and its association with immune-related pathways and cell types highlight its potential role in the pathogenesis of sepsis.

ITIH4 in Rheumatoid Arthritis Pathogenesis: Network Pharmacology and Molecular Docking Analysis Identify CXCR4 as a Potential Receptor

Elevated levels of Inter-alpha-trypsin-inhibitor heavy chain 4 (ITIH4) have grabbed attention in rheumatoid arthritis (RA) pathogenesis, though its precise mechanisms remain unexplored. To elucidate these mechanisms, a comprehensive strategy employing network pharmacology and molecular docking was utilized. RA targets were sourced from the DisGeNET Database while interacting targets of ITIH4 were retrieved from the STRING and Literature databases. Venny 2.1 was used to identify overlapping genes, followed by Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) through Cytoscape 3.10.2 software, and molecular docking was performed in the ClusPro server. The study identified 18 interacting proteins of ITIH4 associated with RA, demonstrating their major involvement in the chemokine signaling pathway by enrichment analysis. Molecular docking of ITIH4 with the 18 proteins revealed that C-X-C chemokine-receptor type 4 (CXCR4), a major protein associated with chemokine signaling, has the highest binding affinity with ITIH4 with energy -1705.7 kcal/mol forming 3 Hydrogen bonds in the active site pocket of ITIH4 with His441, Arg288, Asp443 amino acids. The effect of ITIH4 on CXCR4 was analyzed via knockdown studies in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), demonstrating the significant downregulation of CXCR4 protein expression validated by Western blot in RA-FLS. In conclusion, it was speculated that CXCR4 might serve as a potential receptor for ITIH4 to activate the chemokine signaling, exacerbating RA pathogenesis.

The function of the inter-alpha-trypsin inhibitors in the development of disease

Through the formation of covalent connections with hyaluronic acid (HA), the inter-α-trypsin inhibitor (IαI) family collaborates to preserve the stability of the extracellular matrix (ECM). The five distinct homologous heavy chains (ITIH) and one type of light chain make up the IαI family. ITIH alone or in combination with bikunin (BK) has been proven to have important impacts in a number of earlier investigations. This implies that BK and ITIH might be crucial to both physiological and pathological processes. The functions of BK and ITIH in various pathophysiological processes are discussed independently in this paper. In the meanwhile, this study offers suggestions for further research on the roles of BK and ITIH in the course of disease and summarizes the plausible mechanisms of the previous studies.

Linkage of serum ITIH4 with Th2 signature cytokine, inflammation, exacerbation risk and severity in childhood asthma

Aim: ITIH4 has anti-inflammatory properties toward eosinophilic/neutrophilic inflammation. This study aimed to explore clinical value of ITIH4 in childhood asthma.Materials & methods: Serum ITIH4 and inflammatory cytokines were determined in 120 childhood asthma patients by enzyme-linked immunosorbent assay.Results: In the entire and acute exacerbation patients, ITIH4 positively associated with IFN-γ, but negatively related to proinflammatory cytokines. ITIH4 was lowest in patients with acute exacerbation, followed by chronic persistent, and highest in clinical remission. By receiver-operating characteristic analysis, ITIH4 potentially estimated acute exacerbation asthma risk. Moreover, ITIH4 negatively related to exacerbation severity in acute exacerbation patients.Conclusion: Serum ITIH4 negatively links with Th2 cell signature cytokine, proinflammatory cytokines, exacerbation risk and severity in childhood asthma.

Investigating the Impact of Vitamin A and Amino Acids on Immune Responses in Celiac Disease Patients

Amino acids (AAs) and vitamin imbalances are observed in celiac disease (CD). This study evaluated the plasma profile of vitamin A and AAs and the expression level of IL-2, IL-4, IL-10, IL-12 and TGFβ in CD patients. A total of 60 children and adults with CD and 40 healthy controls (HCs) were included. The plasma profile of Vitamin A and AAs and the mRNA expression levels of target genes were assessed. Active adult patients exhibited a decrease in Vitamin A levels (p = 0.04) and an increase in IL-2 (p = 0.008) and IL-12 (p = 0.007) mRNA expression compared to the HCs. The treated adult patients showed elevated Serine (p = 0.003) and Glycine (p = 0.04) levels, as well as increased IL-12 (p < 0.0001) mRNA expression, and a decrease in Tryptophan (p = 0.04) levels relative to the controls. Additionally, the treated adult patients had higher plasma levels of Threonine compared to both the active (p = 0.04) and control (p = 0.02) subjects, and the increased mRNA expression of IL-4 (p = 0.01) in comparison to the active patients. In active children with CD, the IL-2 mRNA level was found to be higher than in the controls (p < 0.0001) and in the treated children (p = 0.005). The treated children with CD exhibited decreased plasma levels of Tryptophan (p = 0.01) and Isoleucine (p = 0.01) relative to the controls, and the increased mRNA expression of TGFβ (p = 0.04) relative to the active patients. Elevated levels of specific AAs (Serine, Glycine, Threonine) in the treated CD patients suggested their potential to improve intestinal damage and inflammation, while decreased levels of Tryptophan and Isoleucine highlighted the need for dietary intervention.