Lin-lin Bai

Hebei Medical University, Chentow, Hebei, China

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Publications (3)5.49 Total impact

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    ABSTRACT: AIM: Our previous investigation demonstrated that plasminogen activator inhibitor-1 (PAI-1) siRNA ameliorated bleomycin (BLM)-induced rat lung fibrosis. The present study was undertaken to explore the effect and the mechanism of PAI-1 siRNA and plasmid pcDNA on the proliferation and apoptosis of cultured fibroblasts from BLM-induced fibrotic lung tissues. MATERIALS AND METHODS: The fibroblasts from BLM-induced fibrotic lung tissue were isolated and transfected using PAI-1 siRNA and plasmid pcDNA-PAI-1. The techniques of real time RT-PCR and/or western blot were used to determine the expression of PAI-1, α-smooth muscle actin (α-SMA) (real time RT-PCR only), collagen type-1 and type-3 (real time RT-PCR only), and the levels of caspase-3, ERK and AKT signal molecules. The proliferation of fibroblasts was measured by cell cycle with flow cytometry. The intracellular concentration of Ca(2+) was examined by confocal laser microscopy. RESULTS: PAI-1 siRNA downregulated the PAI-1 mRNA expression by 70%±7% at 24h and protein expression by 73.5%±10% and 42%±3% at 48h and 72h compared to Non-specific siRNA group. Flow cytometry showed that the fibroblasts at the G(2)M+S phase were significantly reduced by 20.56±1.03% after transfecting PAI-1 siRNA and were significantly increased by 43.8±1.21% after transfecting plasmid pcDNA-PAI-1. The mRNA expressions of α-SMA, collagen type-1and type-3 were downregulated after transfecting the PAI-1 siRNA, while upregulated after the transfection of pcDNA-PAI-1. PAI-1 siRNA increased the level of caspase-3, inhibited the expressions of p-ERK and p-AKT protein molecules, while the pcDNA-PAI-1 transfection showed a reversal effect on these expressions. Intracellular Ca(2+) concentration was decreased after transfecting PAI-1 siRNA, whereas increased after transfecting pcDNA-PAI-1. CONCLUSION: PAI-1 promotes the proliferation, transforming into myofibroblasts, collagen synthesis, and inhibits apoptosis of pulmonary fibroblasts by activating Ca(2+), ERK and AKT signaling pathway. Decreasing PAI-1 expression is an available strategy in inhibiting the progression of pulmonary fibrosis.
    Thrombosis Research 09/2012; · 3.13 Impact Factor
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    ABSTRACT: Plasminogen activator inhibitor-1 (PAI-1) is involved in the progression of pulmonary fibrosis. The present study was undertaken to examine the effects on pulmonary fibrosis of silencing PAI-1 expression with small interfering RNA (siRNA) and to assess the possible underlying mechanisms. Male Wistar rats were subjected to intratracheal injection of bleomycin (BLM, 5 mg/kg, 0.2 mL) to induce pulmonary fibrosis. Histopathological changes of lung tissue were examined with HE or Masson's trichrome staining. The expression levels of α-smooth muscle actin (α-SMA), collagen type-I and type-III, caspase-3, as well as p-ERK1/2 and PI3K/Akt in the lung tissue were evaluated using imunohistochemistry and Western blot analyses. The fibroblasts isolated from BLM-induced fibrotic lung tissue were cultured and transfected with pcDNA-PAI-1 or PAI-1siRNA. The expression level of PAI-1 in the fibroblasts was measured using real time RT-PCR and Western blot analysis. The fibroblast proliferation was evaluated using MTT assay. Intratracheal injection of PAI-1-siRNA (7.5 nmoL/0.2 mL) significantly alleviated alveolitis and collagen deposition, reduced the expression of PAI-1, α-SMA, collagen type-I and collagen type-III, and increased the expression of caspase-3 in BLM-induced fibrotic lung tissue. In consistence with the in vivo results, the proliferation of the cultured fibroblasts from BLM-induced fibrotic lung tissue was inhibited by transfection with PAI-1-siRNA, and accelerated by overexpression of PAI-1 by transfection with pcDNA-PAI-1. The expression of caspase-3 was increased as a result of PAI-1 siRNA transfection, and decreased after transfection with pcDNA-PAI-1. In addition, the levels of p-ERK1/2 and PI3K/Akt in the fibrogenic lung tissue were reduced after treatment with PAI-1siRNA. The data demonstrate that PAI-1 siRNA inhibits alveolitis and pulmonary fibrosis in BLM-treated rats via inhibiting the proliferation and promoting the apoptosis of fibroblasts. Suppression ERK and AKT signalling pathways might have at least partly contributed to this process. Targeting PAI-1 is a promising therapeutic strategy for pulmonary fibrosis.
    Acta Pharmacologica Sinica 06/2012; 33(7):897-908. · 2.35 Impact Factor
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    ABSTRACT: To explore the effect of plasminogen activator inhibitor-1 (PAI-1) on the proliferation and conversion of rat embryonic lung fibroblasts and the synthesis of collagen, and therefore to explore the function of PAI-1 in pulmonary fibrosis. The embryonic lung fibroblasts from pregnant Wistar rats were isolated and cultured in vitro. The reproduction rate of fibroblasts at 12 h, 24 h, and 48 h after being stimulated by PAI-1 with different concentrations (5, 10, 20, 40, 80, and 100 µg/L) was measured by MTT assay. After being stimulated by PAI-1 with the most suitable concentration (20 µg/L) for 48 h and 72 h, the expression of proliferating cell nuclear antigen (PCNA) was measured by immunocytochemical technique, and the mRNA expression of α-SMA and type-1 collagen at 24 h and 48 h was measured by real-time PCR. PAI-1 with different concentrations stimulated the proliferation of fibroblasts. The highest proliferation rate and absorbance in concentration of 20 µg/L and at 12 h were 62.6% and 0.573 ± 0.039. The comparison of different concentrations showed that the difference was significant (F = 111.112, P = 0.000). Therefore, 20 µg/L was selected as the most suitable concentration. Using immunocytochemical method, the optical density of PCNA at 48 h and 72 h were 3685 ± 686 and 2530 ± 477 after being stimulated with 20 µg/L PAI-1. The comparison showed significant difference (F = 7.85, P = 0.02). The expression of α-SMA increased (230 ± 11)% and (159 ± 9)% at 24 h and 48 h after being stimulated with 20 µg/L PAI-1, and the difference was significant (F = 39.92, P = 0.0003). The expression of type-1 collagen increased (92 ± 8)% and (65 ± 12)%, the difference being significant (F = 32.61, P = 0.0006). PAI-1 can promote the proliferation and conversion of fibroblasts and the synthesis of collagen, which may be involved in the pathogenesis of pulmonary interstitial fibrosis.
    Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases 07/2011; 34(7):500-3.