Myeloid-specific expression of Stat3C results in conversion of bone marrow mesenchymal stem cells into alveolar type Ⅱ epithelial cells in the lung

Bone marrow mesenchymal stem cells (BMSCs) and myeloid lineage cells originate from the bone marrow, and influence each other in vivo. To elucidate the mechanism that controls the interrelationship between these two cell types, the signaling path- way of signal transducer and activator of transcription 3 (Stat3) was activated by overexpressing Stat3C in a newly established c-fms-rtTA/(TetO)7-CMV-Stat3C bitransgenic mouse model, In this system, Stat3C-Flag fusion protein was overexpressed in myeloid lineage cells after doxycycline treatment. Stat3C overexpression induced systematic elevation of macrophages and neutrophils in multiple organs. In the lung, tissue neoplastic pneumocyte proliferation was observed. After in vitro cultured hSP-B 1.5-kb lacZ BMSCs were injected into the bitransgenic mice, BMSCs were able to repopulate in multiple organs, self-renew in the bone marrow and spleen, and convert into alveolar type II epithelial cells. The bone marrow transplantation study indicated that increases of myeloid lineage cells and BMSC-AT II cell conversion were due to malfunction of myeloid progenitor cells as a result of Stat3C overexpression. The study supports the concept that activation of the Stat3 pathway in myeloid cells plays an important role in BMSC function, including homing, repopulating and converting into residential AT II epithelial cells in the lung.

An LC-MS/MS method for simultaneous analysis of the cystic fibrosis therapeutic drugs colistin,ivacaftor and ciprofloxacin

Inhaled antibiotics such as colistin and ciprofloxacin are increasingly used to treat bacterial lung infections in cystic fibrosis patients.In this study,we established and validated a new HPLC-MS/MS method that could simultaneously detect drug concentrations of ciprofloxacin,colistin and ivacaftor in rat plasma,human epithelial cell lysate,cell culture medium,and drug transport media.An aliquot of200 μL drug-containing rat plasma or cell culture medium was treated with 600 μL of extraction solution(acetonitrile containing 0.1% formic acid and 0.2% trifluoroacetic acid(TFA)).The addition of 0.2% TFA helped to break the drug-protein bonds.Moreover,the addition of 0.1% formic acid to the transport medium and cell lysate samples could significantly improve the response and reproducibility.After vortexing and centrifuging,the sample components were analyzed by HPLC-MS/MS.The multiple reaction monitoring mode was used to detect the following transitions:585.5-101.1(colistin A),578.5-101.1(colistin B),393.2-337.2(ivacaftor),332.2-314.2(ciprofloxacin),602.3-101.1(polymyxin B1 as internal standard(IS)) and 595.4-101.1(polymyxin B2 as IS).The running time of a single sample was only 6 min,making this a time-efficient method.Linear correlations were found for colistin A at 0.029-5.82 μg/m L,colistin B at 0.016-3.14 μg/m L,ivacaftor at 0.05-10.0 μg/m L,and ciprofloxacin at 0.043-8.58 μg/m L.Accuracy,precision,and stability of the method were within the acceptable range.This method would be highly useful for research on cytotoxicity,animal pharmacokinetics,and in vitro drug delivery.

Ion therapy of pulmonary fibrosis by inhalation of ionic solution derived from silicate bioceramics

Pulmonary fibrosis(PF)is a chronic and progressively fatal disease,but clinically available therapeutic drugs are limited due to efficacy and side effects.The possible mechanism of pulmonary fibrosis includes the damage of alveolar epithelial cells II(AEC2),and activation of immune cells such as macrophages.The ions released from bioceramics have shown the activity in stimulating soft tissue derived cells such as fibroblasts,endothelia cells and epithelia cells,and regulating macrophage polarization.Therefore,this study proposes an“ion therapy”approach based on the active ions of bioceramic materials,and investigates the therapeutic effect of bioactive ions derived from calcium silicate(CS)bioceramics on mouse models of pulmonary fibrosis.We demonstrate that silicate ions significantly reduce pulmonary fibrosis by simultaneously regulating the functions of AEC2 and macrophages.This result suggests potential clinical applications of ion therapy for lung fibrosis.