Regulatory role of RGMb in lung injury promoted by the combination of carbon ion irradiation and anti-PD-1 antibody through Erk1/2 and p38 MAPK pathways.

The combination of carbon ion radiotherapy and anti-PD-1 antibody represents a new approach to treating thoracic tumors. However, the lung damage caused by this combination therapy may limit its use, and the potential mechanisms for this are worthy of investigation. The objective of this research was to examine the potential involvement of repulsive guidance molecule b (RGMb) in lung damage promoted by the utilization of carbon ion irradiation combined with an anti-PD-1 antibody. The C57BL/6 mice have been randomly separated into four distinct groups: control, anti-PD-1, whole thorax carbon ion irradiation, and irradiation in combination with anti-PD-1 treatment groups (combination group). Detection of pathological changes in lung tissue using HE staining. Detection of pulmonary fibrosis by Masson staining and the hydroxyproline assay. ELISA to detect TNF-α, TGF-ß, IL-6, and IL-1ß expression levels within lung homogenates. The expression of RGMb, p38 MAPK, and Erk1/2 pathways was detected using a fully automated digital Western blotting system WES (ProteinSimple, USA). Flow cytometry was employed to analyze tissue-resident memory T cells (TRM) within the lung. Subsequently, the siRNA gene was employed to induce the downregulation of RGMb in mice in order to validate the involvement of RGMb in radiation-immune lung injury. The present study observed a significant increase in both inflammatory and fibrotic indicators within the mice group's lung tissue that received the combination treatment. The combination group exhibited elevated levels of TGF-ß, TNF-α, IL-6, and IL-1ß in lung homogenates. Anti-PD-1 antibody and carbon ion irradiation, upregulated RGMb, phospho-p38 MAPK and phospho-Erk1/2. The results obtained from the flow cytometry analysis indicated that the combination group was significantly higher in the number of clonal expansion TRMs, which were predominantly characterized by the expression of CD8+CD103+CD69-TRMs. The downregulate of RGMb via siRNA in mice resulted in a decrease in phospho-p38 MAPK and phospho-Erk1/2. The combination group exhibited a reduction in TNF-α, TGF-ß, IL-6, and IL-1ß in their lung tissues, and the number of CD8+CD103+CD69-TRM was significantly reduced. The combination group exhibited a significant improvement in inflammatory and fibrotic indicators within the lung tissues. Anti-PD-1 antibody and carbon ion irradiation synergistically regulate RGMb, leading to strong clonal expansion of lung TRM through the p38 MAPK and Erk1/2 pathways. The present study offers valuable insights into the treatment of lung injury due to the combined administration of carbon ion radiotherapy and anti-PD-1 antibody therapy.

Curcumin mediates repulsive guidance molecule B (RGMb) in the treatment mechanism of renal fibrosis induced by unilateral ureteral obstruction.

In this study, we explored the role and mechanism of repulsive guidance molecule B (RGMb, also known as Dragon) in the protective effects of curcumin against renal fibrosis and verified Dragon's effect on renal tubular epithelial cell apoptosis and cell programmability. Unilateral ureteral obstruction (UUO) was surgically induced in rats to establish a model of renal interstitial fibrosis (RIF). The rats were then treated with curcumin. Curcumin prominently decreased the serum creatinine (SCr) and blood urea nitrogen (BUN) levels, and also improved the tubular injury in the UUO-induced rats. Curcumin significantly downregulated the TGF-ß1, P-Smad2/3, cleaved caspase-3, cleaved caspase-8 and Dragon levels. Dragon knockdown also markedly reduced the TGF-ß1, P-Smad2/3, Smad2/3, cleaved caspase-3, cleaved caspase-8, fibronectin, collagen I, collagen IV, vimentin, and α-SMA expression levels. Conversely, Dragon overexpression caused higher expression levels of these proteins, and curcumin reversed this effect. Furthermore, Dragon knockdown increased the E-cadherin levels, whereas Dragon overexpression decreased these levels. Overexpressing Dragon significantly decreased the cell viability, and curcumin reversed this effect. In conclusion, curcumin acted on Dragon and attenuated RIF in UUO rat models. Curcumin downregulated the TGF-ß1/Smad signaling pathway and inhibited Dragon and fibrogenic molecules in both rats and HK-2 cells.

Blockade of RGMb inhibits allergen-induced airways disease.

BACKGROUND: Allergic asthma causes morbidity in many subjects, and novel precision-directed treatments would be valuable. OBJECTIVE: We sought to examine the role of a novel innate molecule, repulsive guidance molecule b (RGMb), in murine models of allergic asthma. METHODS: In models of allergic asthma using ovalbumin or cockroach allergen, mice were treated with anti-RGMb or control mAb and examined for airway inflammation and airway hyperreactivity (AHR), a cardinal feature of asthma. The mechanisms by which RGMb causes airways disease were also examined. RESULTS: We found that blockade of RGMb by treatment with anti-RGMb mAb effectively blocked the development of airway inflammation and AHR. Importantly, blockade of RGMb completely blocked the development of airway inflammation and AHR, even if treatment occurred only during the challenge (effector) phase. IL-25 played an important role in these models of asthma because IL-25 receptor-deficient mice did not develop disease after sensitization and challenge with allergen. RGMb was expressed primarily by innate cells in the lungs, including bronchial epithelial cells (known producers of IL-25), activated eosinophils, and interstitial macrophages, which in the inflamed lung expressed the IL-25 receptor and produced IL-5 and IL-13. We also found that neogenin, the canonical receptor for RGMb, was expressed by interstitial macrophages and bronchial epithelial cells in the inflamed lung, suggesting that an innate RGMb-neogenin axis might modulate allergic asthma. CONCLUSIONS: These results demonstrate an important role for a novel innate pathway in regulating type 2 inflammation in patients with allergic asthma involving RGMb and RGMb-expressing cells, such as interstitial macrophages and bronchial epithelial cells. Moreover, targeting this previously unappreciated innate pathway might provide an important treatment option for allergic asthma.

Circular RNA_0001073 (circ_0001073) Suppresses The Progression of Non-Small Cell Lung Cancer via miR-582-3p/RGMB Axis.

OBJECTIVE: Reportedly, circular RNAs (circRNAs) exert a crucial regulatory role in cancer. Circ_0001073 is derived from exons 3-5 of ACVR2A gene, which inhibits cancer progression. However, the role and mechanism of circ_0001073 in non-small cell lung cancer (NSCLC) are unclear. This study aimed to explore the role and mechanism of circ_0001073 in the development of NSCLC. MATERIALS AND METHODS: In this experimental study, microarray analysis was employed to filter differential expressed circRNAs in NSCLC tissues. Also, circ_0001073, microRNA-582-3p (miR-582-3p), and repulsive guidance molecule B (RGMB) mRNA expressions were examined by quantitative real-time polymerase chain reaction (qRT-PCR). NSCLC cell multiplication was measured by the cell counting kit-8 (CCK-8) assay. Scratch healing experiment and Transwell experiment were performed to assess cell migration and invasion, respectively. Flow cytometry was applied to analyze the apoptosis of NSCLC cells. Western blot was employed to assess RGMB protein expression. Additionally, dualluciferase reporter gene experiment and RNA immunoprecipitation (RIP) experiment were applied to probe the binding sites between miR-582-3p and circ_0001073 or RGMB. RESULTS: circ_0001073 was remarkably under-expressed in NSCLC tissues and cells. circ_0001073 overexpression impeded the multiplication, migration, and invasion and enhanced the apoptosis of NSCLC cells in vitro. circ_0001073 directly bound to miR-582-3p and acted as a miRNA sponge to regulate RGMB expression. Besides, miR-582-3p overexpression or knockdown of RGMB remarkably reversed the malignant phenotypes of NSCLC cells induced by the up-regulation of circ_0001073 expression. CONCLUSION: Circ_0001073 up-regulates RGMB expression through adsorbing miR-582-3p to inhibit NSCLC progression, suggesting its potential as a novel therapeutic target in NSCLC.