ABSTRACT
Allergic bronchopulmonary aspergillosis (ABPA) is an allergic immunological response to Aspergillus fumigatus (Af) exposure, which induces a strong T helper 2 (Th2) response via mechanisms that have yet to be elucidated. The aim of the present study was to investigate the hypothesis that T2 ribonuclease from Af (Af RNASET2) induces M2type macrophage polarization to produce a T helper 2 (Th2) immune response. Recombinant Af RNASET2 (rAf RNASET2) was expressed and purified in a prokaryotic pET system and BALB/c mice were immunized with rAf RNASET2 for in vivo analyses. Expression levels of M2 polarization factors were evaluated in RAW264.7 macrophages treated with rAf RNASET2 in vitro using flow cytometry, reverse transcriptionquantitative PCR, and western blot analysis. The results predicted that the mature Af RNASET2 protein (382 amino acids; GenBank no. MN593022) contained two conserved amino acid sequence (CAS) domains, termed CAS1 and CAS2, which are also characteristic of the RNASET2 family proteins. The protein expression levels of the Th2related cytokines interleukin (IL)4, IL10, and IL13 were upregulated in mice immunized with rAf RNASET2. RAW264.7 macrophages treated with rAf RNASET2 showed increased mRNA expression levels of M2 factors [arginase 1, Il10, and Il13]; however, there was no difference in cells treated with rAf RNASET2 that had been inactivated with a ribonuclease inhibitor (RNasin). The protein expression levels of IL10 in macrophage culture supernatant were also increased following stimulation with rAf RNASET2. In addition, rAf RNASET2 upregulated the expression of phosphorylated mitogen activated protein kinases (MAPKs) in RAW264.7 cells, whereas MAPK inhibitors attenuated rAf RNASET2induced IL10 expression in RAW264.7 cells. In conclusion, the present study reveals that high rAf RNASET2 activity is required for rAf RNASET2induced M2 polarization of macrophages and suggests an important immune regulatory role for Af RNASET2 in ABPA pathogenesis.
Subject(s)
Aspergillus fumigatus/enzymology , Endoribonucleases/metabolism , Macrophages/cytology , Macrophages/metabolism , Th2 Cells/cytology , Th2 Cells/metabolism , Animals , Endoribonucleases/genetics , Female , Interleukin-10/metabolism , Interleukin-13/metabolism , Interleukin-4/metabolism , Mice , Mice, Inbred BALB C , RAW 264.7 Cells , Th2 Cells/immunologyABSTRACT
BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has become an immense public health burden, first in China and subsequently worldwide. Developing effective control measures for COVID-19, especially measures that can halt the worsening of severe cases to a critical status is of urgent importance. CASE SUMMARY: A 52-year-old woman presented with a high fever (38.8 °C), chills, dizziness, and weakness. Epidemiologically, she had not been to Wuhan where COVID-19 emerged and did not have a family history of a disease cluster. A blood test yielded a white blood cell count of 4.41 × 109/L (60.6 ± 2.67% neutrophils and 30.4 ± 1.34% lymphocytes). Chest imaging revealed bilateral ground-glass lung changes. Based on a positive nasopharyngeal swab nucleic acid test result and clinical characteristics, the patient was diagnosed with COVID-19. Following treatment with early non-invasive ventilation and a bundle pharmacotherapy, she recovered with a good outcome. CONCLUSION: Early non-invasive ventilation with a bundle pharmacotherapy may be an effective treatment regimen for the broader population of patients with COVID-19.
