Background： The previous study showed that mycophenolic acid （MPA） synergizing with lipopolysaccharide （LPS） promotcd interleukin （IL）-1β release, but the mechanism is unclear. This study aimed to investigate ...Background： The previous study showed that mycophenolic acid （MPA） synergizing with lipopolysaccharide （LPS） promotcd interleukin （IL）-1β release, but the mechanism is unclear. This study aimed to investigate the nlechanism ofMPA synergizing with LPS to induce IL-1β release. Methods： Undiluted human blood cells, THP- I human rnyeloid leukemia mononuclear cells （THP- 1 ） cells, or monocytes were stimulated with L PS and treated with or without M PA, and the supernatant IL-1β was detected by enzyme-linked immunosorbent assay. The m RN A levels of IL- 1β were detected by real-time quantitative polymerase chain reaction. The intracellular protein levels of nuclear factor kappa B （NF-κ） phospho-p65 （p-p65）, precursor interleukin-1β （pro-IL-1β）, NOD-like receptor pyrin domain containing-3 （NLRP3）, and cysteine aspartic acid-specific protease-1 （caspase-1 ） p20 in THP-1 cell were measured by Western blot. Results： The MPA alone failed to induce IL-1β, whereas MPA synergized with LPS to increase IL-1β in a dose-dependent manner （685.00 ± 20.00 pg/ml in LPS ＋ 5 μmol/L MPA group, P =0.035; 742.00 ± 31.58 pg/ml in LPS ＋ 25 μmol/L MPA group, P = 0.017：1000.00 ± 65.59 pg/ml in LPS ＋ 75 μmol/L MPA group, P = 0.024： versus 408.00 ± 35.50 pg/ml in LPS group）. MPA alone has no effect on the IL-1β mRNA expression, LPS induced the expression of IL-1β mRNA 2761 fold, and LPS ＋ MPA increased the IL-1β expression 3018 fold, which had the same effect with LPS group （P = 0.834）. MPA did not affect the intracellular NF-κB p-p65 and pro-IL-1β protein levels but activated N LRP3 inflammasonae. Ac-YVAD-cmk blocked the activation ofcaspase-1 and subsequently attenuated IL- 1β secretion （ 181.00 ± 45.24 pg/ml in LPS ＋ M PA ＋ YVAD group vs. 588.00 ± 41.99 pg/ml in LPS ＋ M PA group, P= 0.014）. Conclusions： Taken together, MPA synergized with LPS to induce IL- 1β release via the activation of caspase- 1, rather than the enhanced production ofpro-IL-1β. These findings suggested that patients immunosuppressed with mycophenolate mofetil may have overly activated caspase- 1 during infection, which might contribute to a more sensitive host defense response to invading germs.展开更多
基金This study was supported by grants from National Natural Science Foundation of China （No. 81501417 and No. 81671623）.
文摘Background： The previous study showed that mycophenolic acid （MPA） synergizing with lipopolysaccharide （LPS） promotcd interleukin （IL）-1β release, but the mechanism is unclear. This study aimed to investigate the nlechanism ofMPA synergizing with LPS to induce IL-1β release. Methods： Undiluted human blood cells, THP- I human rnyeloid leukemia mononuclear cells （THP- 1 ） cells, or monocytes were stimulated with L PS and treated with or without M PA, and the supernatant IL-1β was detected by enzyme-linked immunosorbent assay. The m RN A levels of IL- 1β were detected by real-time quantitative polymerase chain reaction. The intracellular protein levels of nuclear factor kappa B （NF-κ） phospho-p65 （p-p65）, precursor interleukin-1β （pro-IL-1β）, NOD-like receptor pyrin domain containing-3 （NLRP3）, and cysteine aspartic acid-specific protease-1 （caspase-1 ） p20 in THP-1 cell were measured by Western blot. Results： The MPA alone failed to induce IL-1β, whereas MPA synergized with LPS to increase IL-1β in a dose-dependent manner （685.00 ± 20.00 pg/ml in LPS ＋ 5 μmol/L MPA group, P =0.035; 742.00 ± 31.58 pg/ml in LPS ＋ 25 μmol/L MPA group, P = 0.017：1000.00 ± 65.59 pg/ml in LPS ＋ 75 μmol/L MPA group, P = 0.024： versus 408.00 ± 35.50 pg/ml in LPS group）. MPA alone has no effect on the IL-1β mRNA expression, LPS induced the expression of IL-1β mRNA 2761 fold, and LPS ＋ MPA increased the IL-1β expression 3018 fold, which had the same effect with LPS group （P = 0.834）. MPA did not affect the intracellular NF-κB p-p65 and pro-IL-1β protein levels but activated N LRP3 inflammasonae. Ac-YVAD-cmk blocked the activation ofcaspase-1 and subsequently attenuated IL- 1β secretion （ 181.00 ± 45.24 pg/ml in LPS ＋ M PA ＋ YVAD group vs. 588.00 ± 41.99 pg/ml in LPS ＋ M PA group, P= 0.014）. Conclusions： Taken together, MPA synergized with LPS to induce IL- 1β release via the activation of caspase- 1, rather than the enhanced production ofpro-IL-1β. These findings suggested that patients immunosuppressed with mycophenolate mofetil may have overly activated caspase- 1 during infection, which might contribute to a more sensitive host defense response to invading germs.
