Construction of prediction model of inflammation related genes in idiopathic pulmonary fibrosis and its correlation with immune microenvironment

The role of oxidative stress-related genes in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is an age-related interstitial lung disease of unknown cause. Oxidative stress, an imbalance between oxidants and antioxidants, is implicated in IPF pathogenesis and prognosis but needs further study. We used transcriptome sequencing data (GSE70866) and oxidative stress-related genes from GeneCards. A prognostic risk model for IPF patients was constructed using LASSO. Functional and pathway differences were analyzed between risk score groups, along with comparisons of immune cells and functions. An IPF rat model with vitamin D3 (VD3) intervention was also established. Finally, we used IL-4 to induce M2 macrophages to explore the mechanism of action of CCL2. We identified 483 DEGs and 50 oxidative stress-related DEGs (OSDEGs). Single-factor COX regression identified 34 prognostic OSDEGs, and LASSO identified an 8-gene signature for the risk model. The high-risk group had more CD8 + T cells, macrophages, APC costimulation, and cytokine-cytokine receptor activity. CCL2 was significantly correlated with macrophages in IPF. VD3 inhibited the TGF-β signaling pathway and reduced macrophage M2 infiltration in the rat model. In the IL-4 induced M2 macrophage model, we found that M2 macrophages produced more CCL2, and the production of CCL2 was significantly reduced after VD3 intervention. We established prognostic markers of eight oxidative stress-related genes. The risk score effectively predicts adverse outcomes in IPF. VD3 may alleviate IPF by reducing macrophage infiltration and inhibiting the TGF-β signaling pathway.

The role and therapeutic targeting of the CCL2/CCR2 signaling axis in inflammatory and fibrotic diseases

CCL2, a pivotal cytokine within the chemokine family, functions by binding to its receptor CCR2. The CCL2/CCR2 signaling pathway plays a crucial role in the development of fibrosis across multiple organ systems by modulating the recruitment and activation of immune cells, which in turn influences the progression of fibrotic diseases in the liver, intestines, pancreas, heart, lungs, kidneys, and other organs. This paper introduces the biological functions of CCL2 and CCR2, highlighting their similarities and differences concerning fibrotic disorders in various organ systems, and reviews recent progress in the diagnosis and treatment of clinical fibrotic diseases linked to the CCL2/CCR2 signaling pathway. Additionally, further in-depth research is needed to explore the clinical significance of the CCL2/CCR2 axis in fibrotic conditions affecting different organs.

Identification of PANoptosis-related genes for idiopathic pulmonary fibrosis by machine learning and molecular subtype analysis

Idiopathic pulmonary fibrosis (IPF) is a severe interstitial lung disease characterized by a grim prognosis, in which various forms of cell death are significant contributors to its development. The objective of this study is to explore diagnostic biomarkers and molecular subtypes associated with PANoptosis in IPF, and to develop reliable diagnostic models based on PANoptosis-related mechanisms. The peripheral blood transcriptomic data of IPF from the Gene Expression Omnibus (GEO) database and PANoptosis-related genes from the GeneCards database were utilized to conduct differential gene expression analysis and weighted gene co-expression network analysis (WGCNA), identifying PANoptosis-related differentially expressed genes (PDEGs). We yielded 9 PDEGs and employed machine learning algorithms to identify 3 key diagnostic biomarkers for PANoptosis in IPF: MMP9, FCMR, NIBAN3. Consensus clustering algorithm was applied to recognize two PANoptosis-related subtypes. Cluster 1 exhibited higher abundance of adaptive immune response cells and significant enrichment in DNA damage and repair-related pathways. Cluster 2 exhibited greater prevalence of innate immune response cells and predominant enhancement in pathways related to lipid cholesterol metabolism and vascular remodeling. Diagnostic models were developed with the aid of clinical decision-making and a novel approach to the diagnosis and treatment for IPF.

Updates on the controversial roles of regulatory lymphoid cells in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common and severe form of pulmonary fibrosis, characterized by scar formation in the lung interstitium. Transforming growth factor beta (TGF-β) is known as a key mediator in the fibrotic process, acting on fibroblasts and mediating their proliferation and differentiation into myofibroblasts. Although the immune system is not considered responsible for the initiation of IPF, markers of tolerogenic immunity define the pro-fibrotic microenvironment in the lungs. In homeostatic conditions, regulatory T cells (Tregs) constitute the main lymphoid population responsible for maintaining peripheral tolerance. Similar to Tregs, regulatory B cells (Bregs) represent a recently described subset of B lymphocytes with immunosuppressive functions. In the context of IPF, numerous studies have suggested a role for Tregs in enhancing fibrosis, mainly via the secretion of TGF-β. In humans, most studies show increased percentages of Tregs associated with the severity of IPF, although their exact role remains unclear. In mice, the most commonly used model involves triggering acute lung inflammation with bleomycin, leading to a subsequent fibrotic process. Consequently, data are still conflicting, as Tregs may play a protective role during the inflammatory phase and a deleterious role during the fibrotic phase. Bregs have been less studied in the context of IPF, but their role appears to be protective in experimental models of lung fibrosis. This review presents the latest updates on studies exploring the implication of regulatory lymphoid cells in IPF and compares the different approaches to better understand the origins of conflicting findings.

A novel model for predicting prognosis in patients with idiopathic pulmonary fibrosis based on endoplasmic reticulum stress-related genes

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic disease of unknown pathogenic origin. Endoplasmic reticulum (ER) stress refers to the process by which cells take measures to ER function when the morphology and function of the reticulum are changed. Recent studies have demonstrated that the ER was involved in the evolution and progression of IPF. In this study, we obtained transcriptome data and relevant clinical information from the Gene Expression Omnibus database and conducted bioinformatics analysis. Among the 544 ER stress-related genes (ERSRGs), 78 were identified as differentially expressed genes (DEGs). These DEGs were primarily enriched in response to ER stress, protein binding, and protein processing. Two genes (HTRA2 and KTN1) were included for constructing an accurate molecular signature. The overall survival of patients was remarkably worse in the high-risk group than in the low-risk group. We further analyzed the difference in immune cells between high-risk and low-risk groups. M0 and M2 macrophages were significantly increased in the high-risk group. Our results suggested that ERSRGs might play a critical role in the development of IPF by regulating the immune microenvironment in the lungs, which provide new insights on predicting the prognosis of patients with IPF.