Integrin beta-1 as a critical gene in radiation-induced injury: Bioinformatic and experimental verification

Objective: To investigate the role of integrin beta-1 (Itgb1) in radiation-induced tissue injury and elucidate its underlying molecular mechanisms. Methods: Differentially expressed genes associated with radiation injury were identified from the Gene Expression Omnibus (GEO) microarray database through bioinformatics analysis, followed by enrichment analysis to determine core hub genes. In vitro, Itgb1 was silenced using siRNA transfection in human chronic myeloid leukemia K562 and mouse alveolar epithelial MLE-12 cells. Protein expression was assessed by Western blot, while cell proliferation, apoptosis, and reactive oxygen species (ROS) levels were quantified by flow cytometry following Itgb1 inhibition. In vivo, C57BL/6 mice were divided into 4 experimental groups (n = 5 per group): Control (intraperitoneal injection of PBS without irradiation), RGD (intraperitoneal injection of RGD 10 mg/kg without irradiation), IR + PBS (8 Gy 60Co γ-ray total body irradiation with PBS), and IR + RGD (intraperitoneal injection of RGD 10 mg/kg, 2 h prior to 8 Gy 60Co γ-ray total body irradiation). Bronchoalveolar lavage fluid (BALF) was collected for macrophage analysis. Lung and intestine tissues were subjected to hematoxylin-eosin (H&E) staining and immunofluorescence (IF) examination. Peripheral blood samples were analyzed to evaluate hematopoietic function. Results: Bioinformatics analysis identified Itgb1 as a hub gene in radiation-induced injury. Western blot analysis demonstrated significant upregulation of Itgb1 protein following irradiation. In K562 cells, Itgb1 expression peaked at 12 h post-irradiation (t = 3.07, P < 0.01) and declined by 24 h, whereas MLE-12 cells exhibited sustained elevation at both time points (t = 10.44, P < 0.0001). Itgb1 silencing significantly exacerbated radiation-induced cellular damage. In K562 cells, knockdown reduced S-phase proliferation from 52.49% to 36.41% (t = 9.64, P < 0.01), increased apoptosis (t = 11.36, P < 0.001), and elevated ROS levels (t = 3.62, P < 0.05). Comparable effects were observed in MLE-12 cells: reduced proliferation (46.82% to 37.98%, t = 12.78, P < 0.0001), enhanced apoptosis (t = 10.16, P < 0.0001), and increased ROS (t = 5.58, P < 0.0001). In vivo, Itgb1 inhibition aggravated radiation-induced pulmonary, intestinal and hematopoietic injuries, characterized by increased inflammatory infiltration, alveolar septal thickening, and decreased peripheral blood cell counts (t = 2.34, P < 0.01). These findings indicate that Itgb1 functions as a protective factor against radiation injury. Conclusions: This study elucidates Itgb1 critical radioprotective role, where compensatory upregulation constitutes an endogenous defense mechanism, while its deficiency exacerbates injury through amplified apoptosis and inflammation, highlighting its clinical utility as a therapeutic target.