Topotecan Mitigates Lipopolysaccharide Induced Inflammation In Macrophages And An Acute Lung Injury Mouse Model

Background and ObjectiveAcute lung injury and acute respiratory distress syndrome(ALI/ARDS)are characterized by serious pulmonary inflammation and disruption of the capillary-alveolar barrier,leading to the development of bilateral pulmonary edema and acute respiratory failure,with high mortality ranging 30%?50%in spite of the development in technology of respiratory support and management of critical care patients.The Topoisomerase 1 inhibitor,Topotecan(TPT)has been reported to exhibit anti-inflammatory properties to viral stimulation and protective effects to autoimmune diseases.However,its roles in acute lung injury(ALI)/acute respiratory distress syndrome(ARDS)are still unknown.Methods and MaterialsAfter exposure to LPS(or ORN02)or treated with LPS(or ORN02)and TPT,transcription of TNF-a and IL-1? was analyzed by real-time PCR and concentrations of TNF-a and IL-1? in supernatant was evaluated by ELISA.Lung tissue paraffin sections were stained with hematoxylin-eosin to observe the inflammatory morphological pathology caused by LPS.After BALFs of mice were obtained,total protein was analyzed by BCA assays and ELISA examined concentrations of TNF-a and IL-1?.Microarray analysis and KEGG analyses were applied to determine differentially expressed genes and potentially modified pathways.Real-time PCR and Western blotting were used to verify the microarray results.ResultsTPT(0.1 ?M or 0.5 ?M)treatment reduced production of pro-inflammatory cytokines in LPS-or ORN 02-stimulated THP-I macrophages.Moreover,In a LPS-induced ALI mouse model,we found that TPT(5 mg/kg or 10 mg/kg)caused less severe lung injury and reduced inflammatory cytokines.Microarray analysis showed After TPT administration,THP-1 showed a total of 2358 differentially expressed RNA,including 958 upregulated RNA and 1400 downregulated RNA.pathway analysis revealed that TPT had a significant influence on pathways of focal adhesion,Fc gamma R-mediated phagocytosis,apoptosis,NF-kappa B signaling pathway and TNF signaling pathway.Next,we confirmed that the NF-?B signaling was significantly suppressed by TPT following LPS stimulation.ConclusionsIn summary,our study demonstrated that TPT could attenuate LPS-induced ALI and inflammation,and revealed that suppression of NF-?B signaling pathway play a pivotal role in the anti-inflammatory effects of TPT.Further investigation on the clinical application of TPT is warranted.