Abstract: Tong Jianbo, Du Leilei, Zeng Rong, Wang Liwei, Liu Yuzhen, Duan Zhimin, Chen Qing, Li Min Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu Key Laboratory of Molecular Biology for Skin Diseases, Nanjing 210042, China （Tong JB, Du LL, Zeng R, Wang LW, Liu YZ, Duan ZM, Li M）; Jiangsu Province Blood Center, Nanjing 210042, China （Chen Q） Corresponding authors: Li Min, Email: drlimin@sina.cn; Chen Qing, Email: chenqing90@yahoo.com 【Abstract】 Objective To evaluate the effect of Aspergillus fumigatus on the of tumor necrosis factor-α （TNF-α） and activation of intracellular signaling molecule p38 mitogen-activated protein kinase （p38MAPK） in a human acute monocytic leukemia cell line THP-1. Methods Cultured THP-l cells （2 × 105/ml） were divided into 4 groups to be treated with Aspergillus fumigatus suspensions at concentrations of 106 and 107 colony-forming units （CFU）/ml （106- and 107-CFU/ml Aspergillus fumigatus groups）, 100 mg/L β-glucan （a positive stimulus, β-glucan group）, culture medium （blank control group） respectively for 1, 3 and 6 hours. Real-time fluorescence-based quantitative PCR （qPCR） was conducted to determine the mRNA of TNF-α in the THP-1 cells in the above groups. Some other THP-l cells were treated with 107 CFU/ml Aspergillus fumigatus suspensions （107-CFU/ml Aspergillus fumigatus group）, β-glucan （β-glucan group） and culture medium （blank control group） separately for 24 hours, and enzyme-linked immunosorbent assay （ELISA） was performed to detect the level of TNF-α in the culture supernatant of THP-1 cells. Western blot analysis was conducted to detect the levels of p38MAPK and phosphorylated p38MAPK in THP-1 cells after 15-, 30- and 60-minute treatment with 107 CFU/ml Aspergillus fumigatus suspensions. After 2-hour incubation with the p38MAPK inhibitor SB203580 （20 μmol/L）, some THP-1 cells were additionally treated with 107 CFU/ml Aspergillus fumigatus suspensions, β-glucan and culture medium separately for 6 hours, and those without SB203580 treatment served as the control group. Then, qPCR was performed to measure the mRNA of TNF-α in the THP-1 cells in the above groups. Results The mRNA of TNF-α significantly differed among the 106- and 107-CFU/ml Aspergillus fumigatus groups, β-glucan group and blank control group （F = 110.983, P < 0.001）, and significantly increased over time （F = 701.680, P < 0.001）. After 24-hour treatment with 107 CFU/ml Aspergillus fumigatus suspensions, the TNF-α level（6 236.30 ± 437.12 ng/L）significantly increased compared with the blank control group （132.10 ± 0.61 ng/L, P < 0.01）. Thirty minutes after the treatment with 107 CFU/ml Aspergillus fumigatus suspensions, the phosphorylated p38MAPK level significantly increased, but started to decrease at 60 minutes. The mRNA of TNF-α was significantly lower in the SB203580-treated Aspergillus fumigatus groups （3.83 ± 0.62） than in the SB203580-untreated Aspergillus fumigatus groups （187.23 ± 21.62）. Conclusion After the treatment with Aspergillus fumigatus, human THP-1 cells can activate the signal molecule p38MAPK and secrete TNF-α, suggesting that monocytes may participate in the innate immune response to Aspergillus fumigatus infection.

Key words: Aspergillus fumigatus, Tumor necrosis factor-alpha, p38 Mitogen-activated protein kinases, THP-1 cells