Alveolar epithelial-capillary barrier disruption is a hallmark of Acute Respiratory Distress Syndrome (ARDS). Contribution of mitochondrial dysfunction to the compromised alveolar-capillary barrier in ARDS remains unclear. Mesenchymal stromal cells-derived extracellular vesicles (MSC EVs) are considered as a cell free therapy for ARDS. Mitochondrial transfer was shown to be important for the therapeutic effects of MSCs and MSC EVs. Here we investigated the contribution of mitochondrial dysfunction to the injury of alveolar epithelial and endothelial barriers in ARDS and the ability of MSC EVs to modulate alveolar-capillary barrier integrity through mitochondrial transfer.Primary human small airway epithelial and pulmonary microvascular endothelial cells and human precision cut lung slices (PCLSs) were stimulated with endotoxin or plasma samples from patients with ARDS and treated with MSC EVs, barrier properties and mitochondrial functions were evaluated. LPS-injured mice were treated with MSC EVs and degree of lung injury and mitochondrial respiration of the lung tissue were assessed.Inflammatory stimulation resulted in increased permeability coupled with pronounced mitochondrial dysfunction in both types of primary cells and PCLSs. EVs derived from normal MSCs restored barrier integrity and normal levels of oxidative phosphorylation while EV preparation which did not contain mitochondria was not effective. In vivo, presence of mitochondria was critical for EV ability to reduce lung injury and restore mitochondrial respiration in the lung tissue.In the ARDS environment MSC-EVs improve alveolar-capillary barrier properties through restoration of mitochondrial functions at least partially via mitochondrial transfer.

The melibiose permease of Salmonella typhimurium (MelB St ) catalyzes symport of melibiose with Na + , Li + , or H + , and bioinformatics analysis indicates that a conserved Gly117 (helix IV) is part of the Na + -binding site. We mutated Gly117 to Ala, Pro, Trp, or Arg; the effects on melibiose transport and binding of cosubstrates depended on the physical−chemical properties of the side chain. Compared with WT MelB St , the Gly117 → Ala mutant exhibited little difference in either cosubstrate binding or stimulation of melibiose transport by Na + or Li + , but all other mutations reduced melibiose active transport and efflux, and decreased the apparent affinity for Na + . The bulky Trp at position 117 caused the greatest inhibition of melibiose binding, and Gly117 → Arg yielded less than a 4-fold decrease in the apparent affinity for melibiose at saturating Na + or Li + concentration. Remarkably, the mutant Gly117 → Arg catalyzed melibiose exchange in the presence of Na + or Li + , but did not catalyze melibiose translocation involving net flux of the coupling cation, indicating that sugar is released prior to release of the coupling cation. Taken together, the findings are consistent with the notion that Gly117 plays an important role in cation binding and translocation.

ObjectivesLung adenocarcinoma is considered a unique disease for Asian female non-smokers. We investigated whether plasma microRNA (miRNA) expression profiles are different by the EGFR status and are associated with survival outcomes of the patients.MethodsUsing real-time RT-PCR, we analyzed the expression of 20 miRNAs in the plasma of 105 female patients with lung adenocarcinoma. Kaplan-Meier survival analysis and Cox proportional hazards regression were performed to determine the association between miRNA expression and overall survival. Time dependent receiver operating characteristic (ROC) analysis was also performed.ResultsIn the 20 miRNAs, miR-122 were found differently expressed between wild and mutant EGFR carriers (P=0.018). Advanced disease stage and tumor metastasis were independently associated with poor prognosis of patients with lung adenocarcinoma (P=0.010 and 1.0×10-4). Plasma levels of miR-195 and miR-122 expression were also associated with overall survival in the patients, especially in those with advanced stage (HR=0.23, 95%CI:0.07-0.84; and HR=0.22, 95%CI:0.06-0.77) and EGFR mutation (HR=0.27, 95%CI:0.08-0.96; and HR=0.23, 95%CI=0.06-0.81). Moreover, a model including miR-195, miR-122 may predict survival outcomes of female patients with lung adenocarcinoma (AUC=0.707). ConclusionsCirculating miR-195 and miR-122 may have prognostic values in predicting the overall survival as well as predicting EGFR mutation status in non-smoking female patients with lung adenocarcinoma. Measuring plasma levels of miR-195 and miR-122 may especially be useful in EGFR mutant patients with lung adenocarcinoma.