HMGB1 and RAGE levels in induced sputum correlate with asthma severity and neutrophil percentage.

Previous work indicated that high mobility group box-1 (HMGB1) protein may be involved in neutrophilic asthma. Here, we sought to investigate the correlation between HMGB1 and one of its receptors, receptor for advanced glycosylation end products (RAGE), with the severity of bronchial asthma. Compared to the control group (30 healthy individuals), patients in the asthma group (n=72) exhibited a higher percentage of neutrophils and higher HMGB1 and RAGE levels in induced sputum samples (P<0.05). Concurrently, FEV(1)% was significantly lower in the asthma group (P<0.05). Further, compared to mild and moderate asthma, in patients with severe asthma ACQ scores, the percentage of neutrophils, and HMGB1 levels were significantly higher, while FEV(1)% was significantly lower (P<0.05). The percentage of neutrophils and HMGB1 and RAGE levels were lower after treatment than before treatment (P<0.05). Finally, negative correlations were observed between HMGB1 or RAGE levels and FEV(1)% (r=-0.777 and r=-0.291, P<0.05), and positive correlations were detected between HMGB1 or RAGE levels and percentage of neutrophils (r=0.803 and r=0.326, P<0.05). Additionally, positive correlations were observed between HMGB1 and RAGE levels within the asthma group (r=0.306, P<0.05). Therefore, HMGB1 protein levels correlate with the severity of asthma, and HMGB1 may contribute to the inflammatory process of asthma.

Cloning of the surface layer gene sllB from Bacillus sphaericus ATCC 14577 and its heterologous expression and purification.

A cDNA fragment encoding the S-layer protein SllB cloned from Bacillus sphaericus ATCC 14577 was expressed on the surface of E. coli BL21 (DE3) cells and confirmed by the square lattice structure at the nanoscale level. The amplified gene fragment designed with PCR primers from a specified reference sequence (GenBank accession no. AJ849550) showed a high degree of sequence identity with the known sequences for S-layer protein. The best alignment scores were seen in B. sphaericus strains JG-A12 and NCTC9602, which code for a pre-form protein with a predicted cleavage site located between the two alanine residues 31 and 32. After this signal peptide sequence was removed, the mature protein had a molecular mass of 116.2613 kDa and a theoretical pI of 5.40. Further bioinformatic analysis revealed three S-layer homology (SLH) domains in the N-terminus of the mature protein, positioned at the 1-61, 63-128 and 137-197 residues. The mature S-layer protein was composed of alpha helices (24.86%), extended strands (27.01%), and rich random coils (48.13%). Bioinformatics-driven characterization of SllB may provide scientific evidence for further application of this gene in the fields of nanobiotechnology and biomimetics in the future.