Biological characteristics of molecular subtypes of ulcerative colitis characterized by ferroptosis and neutrophil infiltration.

Clinical ulcerative colitis (UC) is a heterogeneous condition. Moreover, medical interventions are nonspecific, and thus, treatment responses are inconsistent. The aim of this study was to explore the molecular subtypes and biological characteristics of UC based on ferroptosis and neutrophil gene sets. Multiple intestinal mucosa gene expression profiles of UC patients in the Gene Expression Omnibus (GEO) database were downloaded. Unsupervised clustering methods were used to identify potential molecular subtypes based on ferroptosis and neutrophil gene sets. Multiple immune infiltration algorithms were used to evaluate the biological characteristics of the molecular subtypes. Machine learning identifies hub genes for molecular subtypes and analyses their diagnostic efficacy for UC and predictive performance for drug therapy. The relevant conclusions were verified by clinical samples and animal experiments. Four molecular subtypes were identified according to the ferroptosis and neutrophil gene sets: neutrophil, ferroptosis, mixed and quiescent. The subtypes have different biological characteristics and immune infiltration levels. Multiple machine learning methods jointly identified four hub genes (FTH1, AQP9, STEAP3 and STEAP4). Receiver operating characteristic (ROC) curve analysis revealed that the four hub genes could be used as diagnostic markers for UC. The clinical response profile data of infliximab treatment patients showed that AQP9 and STEPA4 were reliable predictors of infliximab treatment response. In human samples the AQP9 and STEAP4 protein were shown to be increased in UC intestinal samples. In animal experiments, the ferroptosis and neutrophil phenotype were confirmed. Dual analysis of ferroptosis and neutrophil gene expression revealed four subgroups of UC patients. The molecular subtype-associated hub genes can be used as diagnostic markers for UC and predict infliximab treatment response.

Sun S ，Mao Y ，Le S ，Zheng M ，Li M ，Chen Y ，Chen J ，Fan Y ，Lv B ... -  《Scientific Reports》

Identification of Diagnosis and Typological Characteristics Associated with Ferroptosis for Ulcerative Colitis via Bioinformatics and Machine Learning.

To investigate and validate ferroptosis genes (FRGs) in ulcerative colitis (UC) for diagnostic, subtype, and biological agent reactivity, with the goal of providing a foundation for the identification of novel therapeutic targets and the rational use of infliximab in clinical practice. UC datasets and FRGs were selected from the Gene Expression Omnibus (GEO) and FerrDb databases. WGCNA was used to identify characteristic genes of UC. LASSO and SVM models were used to discover key FRGs in UC. A nomogram was constructed for diagnosing UC using logistic regression (LR), We performed internal and external validation for the model. Furthermore, we constructed a hub-gene-signature prediction model for the effectiveness of infliximab in treating UC and deployed it on the website. Finally, the hub gene-drug interaction networks were constructed. Nineteen ferroptosis-related genes associated with UC were identified through bioinformatics analysis. FTH1 and GPX4 were two of the down-regulated genes.The seventeen upregulated genes consisted of DUOX1, DUOX2, SOCS1, LPIN1, QSOX1, TRIM21, IDO1, SLC7A11, MUC1, HSPA5, SCD, ACSL3, NOS2, PARP9, PARP14, LCN2, and TRIB2. Five hub genes, including LCN2, QSOX1, MUC1, IDO1, and TRIB2, were acquried via machine learning. The mean auc of internal validation was 0.964 and 0.965 respectively, after using cross-validation and bootstrap in the training set based on the 5 hub-gene diagnostic models. In the external validation set, the AUC reached 0.976 and 0.858. RF model performs best in predicting infliximab effectiveness. In addition, we identified two ferroptosis subtypes. Cluster A mostly overlaps with the high-risk score group, with a hyperinflammatory phenotype. This research indicated that five hub genes related to ferroptosis might be potential markers in diagnosing and predicting infliximab sensitivity for UC.

Wang W ，Song X ，Ding S ，Ma H ... -  《-》

Precision therapy for ulcerative colitis: insights from mitochondrial dysfunction interacting with the immune microenvironment.

Accumulating evidence reveals mitochondrial dysfunction exacerbates intestinal barrier dysfunction and inflammation. Despite the growing knowledge of mitochondrial dysfunction and ulcerative colitis (UC), the mechanism of mitochondrial dysfunction in UC remains to be fully explored. We integrated 1137 UC colon mucosal samples from 12 multicenter cohorts worldwide to create a normalized compendium. Differentially expressed mitochondria-related genes (DE-MiRGs) in individuals with UC were identified using the "Limma" R package. Unsupervised consensus clustering was utilized to determine the intrinsic subtypes of UC driven by DE-MiRGs. Weighted gene co-expression network analysis was employed to investigate module genes related to UC. Four machine learning algorithms were utilized for screening DE-MiRGs in UC and construct MiRGs diagnostic models. The models were developed utilizing the over-sampled training cohort, followed by validation in both the internal test cohort and the external validation cohort. Immune cell infiltration was assessed using the Xcell and CIBERSORT algorithms, while potential biological mechanisms were explored through GSVA and GSEA algorithms. Hub genes were selected using the PPI network. The study identified 108 DE-MiRGs in the colonic mucosa of patients with UC compared to healthy controls, showing significant enrichment in pathways associated with mitochondrial metabolism and inflammation. The MiRGs diagnostic models for UC were constructed based on 17 signature genes identified through various machine learning algorithms, demonstrated excellent predictive capabilities. Utilizing the identified DE-MiRGs from the normalized compendium, 941 patients with UC were stratified into three subtypes characterized by distinct cellular and molecular profiles. Specifically, the metabolic subtype demonstrated enrichment in epithelial cells, the immune-inflamed subtype displayed high enrichment in antigen-presenting cells and pathways related to pro-inflammatory activation, and the transitional subtype exhibited moderate activation across all signaling pathways. Importantly, the immune-inflamed subtype exhibited a stronger correlation with superior response to four biologics: infliximab, ustekinumab, vedolizumab, and golimumab compared to the metabolic subtype. This analysis unveils the interplay between mitochondrial dysfunction and the immune microenvironment in UC, thereby offering novel perspectives on the potential pathogenesis of UC and precision treatment of UC patients, and identifying new therapeutic targets.

Zhang YF ，Fan MY ，Bai QR ，Zhao R ，Song S ，Wu L ，Lu JH ，Liu JW ，Wang Q ，Li Y ，Chen X ... -  《Frontiers in Immunology》

Analysis and identification of ferroptosis-related genes in ulcerative colitis.

Chen C ，Lan B ，Xie G ，Liu Z ... -  《-》

Age-related genes affecting the immune cell infiltration in ulcerative colitis revealed by weighted correlation network analysis and machine learning.

Chen HL ，Liu YH ，Tan CH 《-》