BMSCs mediates endothelial cell autophagy by upregulating miR-155-5p to alleviate ventilator-induced lung injury.

In this study, we explored to detect the effects and mechanism of bone-marrow-derived mesenchymal stem cells (BMSCs) on ventilator-induced lung injury (VILI). We transplanted BMSCs in mice and then induced VILI using mechanical ventilation (MV) treatment. The pathological changes, the content of PaO2 and PaCO2 , wet/dry weight ratio (W/D) of the lung, levels of tumor necrosis factor-α and interleukin-6 in bronchoalveolar lavage fluid, and apoptosis were detected. The autophagy-associated factor p62, LC3, and Beclin-1 expression were analyzed by western blot. The quantitative polymerase chain reaction was applied to detect abnormally expressed microRNAs, including miR-155-5p. Subsequently, we overexpressed miR-155-5p in VILI mice to detect the effects of miR-155-5p on MV-induced lung injury. Then, we carried out bioinformatics analysis to verify the BMSCs-regulated miR-155-5p that target messenger RNA. It was observed that BMSCs transplantation mitigated the severity of VILI in mice. BMSCs transplantation reduced lung inflammation, strengthened the arterial oxygen partial pressure, and reduced apoptosis and the W/D of the lung. BMSCs promoted autophagy of pulmonary endothelial cells accompanied by decreased p62 and increased LC3 II/I and Beclin-1. BMSCs increased the levels of miR-155-5p in VILI mice. Overexpression of miR-155-5p alleviated lung injury in VILI mice following reduced apoptosis and increased autophagy. Finally, TAB2 was identified as a downstream target of miR-155-5p and regulated by miR-155-5p. BMSCs may protect lung tissues from MV-induced injury, inhibit lung inflammation, promote autophagy through upregulating of miR-155-5p.

Expression of chromogranin A-derived antifungal peptide CGA-N12 in Pichia pastoris.

The human chromogranin A-derived peptide CGA-N12, which is composed of 12 amino acid residues with the sequence ALQGAKERAHQQ, showed strong antifungal activity and the least hemolytic activity in previous studies. However, synthetic peptides are relatively expensive to produce. Recombinant expression of peptides in the host cells, such as bacteria or yeast, can fastly provide cost-efficient products of peptides. Here, we developed an innovative system to produce CGA-N12 peptides in the yeast Pichia pastoris GS115 using genetic engineering technology. In order to directly secret short CGA-N12 peptides into the culture media from GS115 cells and enhance its expression effect, the structure of the CGA-N12 coding sequence was designed to mimic that of native α-factor gene of Saccharomyces cerevisiae. Four long primer pairs with sticky end were used to synthesize CGA-N12 expression sequence which contains four copies of CGA-N12 flanked by a Lys-Arg pair and two Glu-Ala repeating units. Endogenous proteases Kex2 and Ste13 in Golgi apparatus recognize and excise Lys-Arg and Glu-Ala pair to release short CGA-N12 peptides from the tandem repeat sequences, respectively. The CGA-N12 peptides were successfully expressed in Pichia pastoris with a yield of up to 30 mg/L of yeast culture as determined using HPLC. Our study indicated that the strategy employed in this work may be a good way to express small-molecule peptides directly in the Pichia pastoris system.

[A clinical analysis of eight proven cases of pulmonary mucormycosis].

OBJECTIVE: To improve the understanding of pulmonary mucormycosis by analyzing the clinical manifestations, imaging features, diagnosis, treatment and prognosis of this disease. METHODS: The clinical data of eight patients diagnosed as pulmonary mucormycosis by histopathologic examination were retrospectively analyzed. RESULTS: Eight patients included six males and two females with age from 36 days to 66 years. Underlying conditions covered diabetes (n = 4), renal transplantation (n = 3), premature (n = 1) and long-term corticosteroid treatment in two cases. Imaging manifestations revealed multiple irregular lumps or nodules in three cases, multiple cavities with thick wall in three cases, diffuse lung infiltrate in one case and lung opacities in one case. The diagnoses of seven patients were confirmed by percutaneous needle lung biopsy and the remaining one was diagnosed with fiberoptic bronchoscopy biopsy. Surgery combined with amphotericin B liposome (60 mg/d for three weeks) was applied to one patient who was cured with no recurrence after a 22 month follow-up. Three cases were given amphotericin B liposome (a newborn with 7mg/d for 62 days, the other two 60 mg/d for 31 days and 70 mg/d for 71 days respectively). All had achieved marked response with follow up from 8 to 29 months, but one patient relapsed and died of recurrent lung mucormycosis. The other three patients were treated with itraconazole 400-200 mg/d from 21 days to 1 year with duration of follow up from 1 month to 20 months. One patient was not evaluable due to missing. Two patients relapsed and one died. CONCLUSION: Pulmonary mucormycosis is difficult to diagnose and treat with a high mortality. Percutaneous transthoracic lung biopsy is a useful diagnostic method. Amphotericin B liposome or itraconazole may be active against mucus. Early control of causes is essential to improve the prognosis and reduce the recurrence in patients with pulmonary mucormycosis.