OBJECTIVETo explore the mechanism of injurious effect of succinic acid on human fibroblast and it's role in bacteroides fragilis infection.

METHODSIn vitro cultured human fibroblasts were challenged by succinic acid in concentrations of 5, 10, 20 and 30 mmol/L (pH5.5), respectively. The cellular activity, apoptosis rate, the collagen synthesis in the supernatant of the cell culture, and the activity of caspase-3 were determined 24 hours after challenge. Isotonic saline challenged fibroblast were employed as control and the changes in the indices before and after succinic acid challenge were observed.

RESULTSAlong with the increase in the concentration of succinic acid, the fibroblast proliferation rate was decreased and so was the collagen synthesis. But the apoptosis rate and caspase-3 activity were increased. The activity of caspase-3 was markedly higher than that in normal control when the succinic acid concentration was 10-30 mmol/L. The cellular activity and collagen synthesis were significantly lower and the apoptosis rate was obviously higher than those in control group when the succinic acid concentration was 20 or 30 mmol/L (P < 0.05).

CONCLUSIONThe proliferation and collagen synthesis in fibroblast culture could be significantly inhibited and the cellular apoptosis could be promoted by succinic acid. The process of wound healing of the wounds infected by bacteroides fragilis would be delayed due to the production of succinic acid by the bacteria.

Apoptosis ; drug effects ; Caspase 3 ; Caspases ; metabolism ; Cells, Cultured ; Collagen ; biosynthesis ; Dose-Response Relationship, Drug ; Fibroblasts ; drug effects ; metabolism ; physiology ; Humans ; Succinic Acid ; pharmacology

OBJECTIVETo study the role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in silica-induced DNA double-strand break repair in human embryo lung fibroblasts (HELF).

METHODSTwo stable transfectants, HELF transfected with DNA-PKcs siRNA (HELF-PKcs) and with negative control siRNA (HELF-NC), were established. HELF cells were treated with 0, 25, 50, 100, 200, 300 and 400 microg/ml silica for 12 h and with 200 microg/ml silica for different times (0, 1, 2, 6, 12 and 24 h). HELF-PKcs and HELF-NC were treated with 200 microg/ml silica for 0, 12 and 24 h. The expression levels of DNA-PKcs and phosphor-H2AX (H2AX) were determined by Western blot. DNA double strand breaks were measured by neutral comet assay.

RESULTSAfter treatment with different doses of silica for 12 h, the levels of H2AX and the percentages of tail DNA increased in concentration-dependent manner. After treatment with 200 microg/ml silica for different times, the levels of H2AX increased in a time-dependent manner. The percentages of tail DNA increased significantly at 6 h, and reaching maximum at 12 h and then decreasing at 24 h. The expression level of DNA-PKcs was suppressed in HELF-PKcs. After treatment with silica at 12 h, the level of H2AX was lower in HELF-PKcs than in HELF-NC, and the percentages of tail DNA increased obviously in both HELF-PKcs and HELF-NC compared with non-treated cells, but no significant difference was found in the percentages of tail DNA between them. The percentages of tail DNA decreased markedly in silica-treated HELF-NC and was significantly lower than in HELF-PKcs at 24 h (P < 0.05).

CONCLUSIONSilica can induce DNA double strand breaks in human embryo lung fibroblasts. DNA-PKcs might play a major role in silica-induced DNA double strand break repair. Silica-induced histone H2AX phosphorylation was dependent on DNA-PKcs.

Cell Line ; DNA Breaks, Double-Stranded ; drug effects ; DNA Repair ; DNA-Activated Protein Kinase ; genetics ; metabolism ; Fibroblasts ; drug effects ; physiology ; Histones ; metabolism ; Humans ; Phosphorylation ; Silicon Dioxide ; pharmacology ; Transfection

BACKGROUNDThrombin is a multifunctional serine protease that plays a crucial role in hemostasis following tissue injury. In addition to its procoagulation effect, thrombin is also a potent mesenchymal cell mitogen, therefore it plays important roles in the local proliferation of mesenchymal cells in the tissue repair process. Reactive oxygen species (ROS) can induce some human cells to proliferate at lower rates while at higher concentrations they promote cells to undergo apoptosis or necrosis. Accumulative evidence suggests that thrombin can induce some cells to produce ROS. Based on these observations, we provide a hypothesis that thrombin can stimulate human lung fibroblasts to produce ROS, which play an important role in human lung fibroblast proliferation.

METHODSROS were detected in fibroblasts at 30 minutes and 60 minutes following thrombin (20 U/ml) exposure using flow cytometry. The ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) was assayed in lung fibroblasts using a commercial kit following treatment with thrombin at different concentrations. NADPH oxidase and the extracellular regulated kinase1/2 (ERK1/2) signaling pathway were detected by Western blotting after thrombin stimulation to lung fibroblasts.

RESULTSThrombin, at 20 U/ml, stimulated human lung fibroblasts (HLF) to generate ROS in a time dependent manner. The ratio of GSH/GSSG in fibroblasts treated with thrombin showed a significant decrease. NADPH oxidase was activated and the ERK1/2 signal pathway was involved in the proliferation process of fibroblasts treated with thrombin.

CONCLUSIONThe activation of NADPH oxidase by thrombin leads to the production of ROS, which promotes fibroblasts proliferation via activation of the ERK1/2 signaling pathway.

Cell Proliferation ; drug effects ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; analysis ; physiology ; Fibroblasts ; drug effects ; physiology ; Flow Cytometry ; Glutathione ; metabolism ; Humans ; Lung ; cytology ; NADPH Oxidases ; analysis ; physiology ; Reactive Oxygen Species ; metabolism ; Signal Transduction ; physiology ; Thrombin ; pharmacology

OBJECTIVETo investigate the role of AcSDKP on collagen synthesis and degradation in cultured rat cardiac fibroblasts.

METHODSNeonatal rat cardiac fibroblasts were isolated and stimulated by PDGF. The cell proliferation was observed by (3)H-TdR incorporation assay. The synthesis of collagen was measured by (3)H-proline incorporation assay. The expression of type I and type III collagen and MMP-1 protein were measured by Western blot. The MMP-2 and MMP-9 activity was evaluated with zymography assay.

RESULTSPDGF stimulated cardiac fibroblasts proliferation with increased collagen synthesis and type I and type III collagen protein expressions as well as MMP-2 and MMP-9 activities and MMP-1 expression. AcSDKP inhibited cardiac fibroblasts proliferation induced by PDGF and reduced collagen synthesis and type I and type III collagen protein expression. AcSDKP also further up-regulated MMP-2 and MMP-9 activities and MMP-1 expression in cardiac fibroblasts induced by PDGF.

CONCLUSIONAcSDKP inhibited proliferation and collagen synthesis and up-regulated matrix metalloproteinases activity or expression induced by PDGF, which was possibly related with the effect of AcSDKP anti-fibrosis.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Collagen ; biosynthesis ; Fibroblasts ; drug effects ; metabolism ; Matrix Metalloproteinase 2 ; biosynthesis ; Matrix Metalloproteinase 9 ; biosynthesis ; Myocytes, Cardiac ; drug effects ; metabolism ; Oligopeptides ; physiology ; Platelet-Derived Growth Factor ; drug effects ; Rats ; Rats, Wistar

OBJECTIVETo investigate the role of calcineurin (CaN) in the lung fibroblast proliferation and collagen synthesis induced by basic fibroblast growth factor (bFGF).

METHODSWe used Western blot and immunohistochemical methods for investigating the content and distribution of calcineurin in the lung tissue. Calcineurin activity in different tissues was measured using (32)P-labelled substrate. In the primary culture of lung fibroblasts, (3)H-thymidine ((3)H-TdR) and (3)H-proline incorporation methods were used to study the effect of cyclosporin A (CsA), an inhibitor of calcineurin, on the lung fibroblast DNA and collagen synthesis stimulated by bFGF.

RESULTSWe found that calcineurin was expressed in lung tissue and has phosphatase activity (7.1 +/- 2.0 pmol Pi/mg pr/min). CsA (10(-8) - 10(-6) mol/L) inhibited lung fibroblast (3)H-TdR incorporation induced by bFGF in a dose-dependent manner, with the inhibitory rates by 20%, 46% and 66% (P < 0.01). CsA (10(-7) - 10(-6) mol/L) inhibited (3)H-proline incorporation in lung fibroblasts stimulated by bFGF, with the inhibitory rates by 21% and 37% (P < 0.01). In a culture medium, CsA (10(-8) - 10(-6) mol/L) inhibited (3)H-proline secretion induced by bFGF in a dose-dependent manner, with the inhibitory rates by 19%, 29% (P < 0.05) and 56% (P < 0.01). CsA (10(-7) mol/L) could inhibit calcineurin activity by 44% in lung fibroblasts (P < 0.01).

CONCLUSIONSCalcineurin is expressed in lung tissue and has phosphatase activity. It is involved in the bFGF stimulated lung fibroblast DNA and collagen synthesis.

Animals ; Calcineurin ; analysis ; physiology ; Cell Division ; Cell Survival ; drug effects ; Collagen ; biosynthesis ; Fibroblast Growth Factor 2 ; pharmacology ; Fibroblasts ; drug effects ; physiology ; Lung ; cytology ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the molecular mechanism of the inhibitory effects of vitamin C on benzo[a]pyrene (B[a]P)-induced changes of cell cycle in human embryo lung fibroblast (HELF) cells.

METHODSThe stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established. Cells were cultured and pretreated with vitamin C before stimulation with B[a]P for 24 h. The expression levels of cyclin D1, CDK4, E2F1, and E2F4 were determined by Western blot. Flow cytometric analysis was employed to detect the distributions of cell cycle.

RESULTSB[a]P significantly elevated the expression levels of cyclin D1, E2F1, and E2F4 in HELF cells. Vitamin C decreased the expression levels of cyclin D1, E2F1, and E2F4 in B[a]P-stimulated HELF cells. Dose-dependent relationships were not found between the different concentrations of vitamin C (10, 100, 500, 1000, and 5000 micromol/L) and the expression levels of cyclin D1, E2F1, and E2F4 in HELF cells. The expression levels of cyclin D1, E2F1, and E2F4 in B[a]P-treated transfectants were lower than those in B[a]P-treated HELF cells. The expression levels of cyclin D1 and E2F4 treated with vitamin C and antisense cyclin D1 were decreased compared with those treated with antisense cyclin D1 alone. The effects of vitamin C combined with antisense CDK4 on the expression levels of cyclin D1 and E2F1/E2F4 were similar to those of antisense CDK4 alone. B[a]P progressed HELF cells from G1 to S phase. Both vitamin C and antisense cyclin D1 suppressed the changes of cell cycle progressed by B[a]P. However, antisense CDK4 did not attenuate the above changes. Vitamin C combined with antisense CDK4 markedly suppressed B[a]P-induced changes of cell cycle as compared with antisense CDK4. But the inhibitory effects of vitamin C combined with antisense cyclin D1 on B[a]P-induced changes of cell cycle were similar to those of vitamin C alone or antisense cyclin D1 alone.

CONCLUSIONSB[a]P progressed HELF cells from G1 to S phase via intracellular signaling pathway of cyclin D1/E2F. Vitamin C may modulate this signaling pathway to protect cells from injury caused by B[a]P.

Ascorbic Acid ; pharmacology ; Benzo(a)pyrene ; Blotting, Western ; methods ; Cell Cycle ; drug effects ; physiology ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Dose-Response Relationship, Drug ; E2F1 Transcription Factor ; metabolism ; Fibroblasts ; cytology ; drug effects ; metabolism ; G1 Phase ; drug effects ; physiology ; Humans ; Lung ; cytology ; embryology ; RNA, Antisense ; genetics ; S Phase ; drug effects ; physiology ; Transfection ; methods

To explore the influence of calculus bovis on the function of primary cultured mice oral fibroblasts, we determined the effects of calculus bovis on the fibroblast proliferation, collagen production, matrix metalloproteinases-2, -9 activities and tissue inhibitor of metalloproteinase-1 production by MTT assay, chloramine T method, gelatin zymography and enzyme-linked immunosorbent assays respectively. The results showed that calculus bovis could significantly inhibit the proliferation of fibroblasts and collagen synthesis in a concentration dependent manner, could significantly (P<0.05) suppress matrix metalloproteinases-2 activity and very significantly (P<0.01) inhibit the production of tissue inhibitor of metalloproteinase-1. In conclusion, the major function of calculus bovis in the process of ulcer healing is not to promote tissue regeneration, the mechanism that calculus bovis inhibits collagen synthesis may be partly due to its ability to very significantly (P<0.01) suppress the production of tissue inhibitor of metalloproteinase-1.
Animals ; Cattle ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cholelithiasis ; chemistry ; veterinary ; Collagen ; drug effects ; metabolism ; Fibroblasts ; cytology ; physiology ; Materia Medica ; pharmacology ; Mice ; Mice, Inbred BALB C ; Mouth Mucosa ; cytology ; Tissue Inhibitor of Metalloproteinase-1 ; drug effects ; metabolism

OBJECTIVELipoxin A(4) is formed by the metabolism of arachidonic acid. Anti-inflammatory and anti-proliferative effect of lipoxin A(4) has been shown in many human diseases. Recently, as a novel high affinity receptor for ligand lipoxin A(4), Lipoxin A(4) receptor-like protein (LRLP) has been identified. Currently close attention is paid to the important contribution of connective tissue growth factor (CTGF) in lung fibrosis. The purpose of the study was to transfect LRLP gene into human lung fibroblasts and investigate the mechanism of its enhancing antagonistic effect of Lipoxin A(4) on human lung fibroblasts proliferation induced by connective tissue growth factor.

METHODSEukaryocytic expression vector pEGFP/LRLP which contained LRLP and green fluorescence protein fusion gene (GFP) was constructed and transfected into human lung fibroblasts (HLF). After selecting with G418, HLF/LRLP cell clone which stably expressed LRLP/GFP fusion protein was isolated and characterized by the laser scanning confocal microscope. Cultured HLF and HLF/LRLP were stimulated for 24 h with CTGF (1 microg/ml) in the presence and absence of pretreatment of Lipoxin A(4) (10.0 nmol/L) for 30 min. Inhibition of cell proliferation was determined by MTT assay. Cell cycle analysis was performed by flow cytometry. Western blot was used to detect the expression of cyclin D(1) protein. Electrophoretic mobility shift assay (EMSA) was employed to detect the DNA binding activity of STAT(3).

RESULTS(1) HLF/LRLP cell clone which stably expressed LRLP and GFP fusion protein was successfully obtained. (2) Proliferation of HLF and HLF/LRLP was induced by 1 microg/ml CTGF. Pretreatment with 10 nm Lipoxin A(4) inhibited the proliferation of HLF and HLF/LRLP. And the inhibitory rate of HLF/LRLP was significantly higher than that of HLF [(54.1 +/- 4.2)%, (21.2 +/- 3.7)%, P < 0.05]. (3) The flow cytometry analysis showed that compared with HLF, more HLF/LRLP were arrested at G(0)/G(1) phase in the presence of pretreatment of Lipoxin A(4). [(76.3 +/- 3.5)%, (60.8 +/- 2.0)%, P < 0.05]. (4) Ten nmol/L Lipoxin A(4) antagonized CTGF induced increase of cyclin D(1) protein expression in HLF and HLF/LRLP. And its antagonistic effect on HLR/LRLP was stronger than that on HLF (P < 0.05). (5) Ten nmol/L Lipoxin A(4) antagonized CTGF induced increase of STAT(3) DNA binding activity, and its antagonistic effect on HLF/LRLP was more powerful than that on HLF (P < 0.05).

CONCLUSIONSTransfection of Lipoxin A(4) receptor-like protein gene enhanced the inhibitory effect of Lipoxin A(4) on human lung fibroblasts proliferation induced by CTGF. Its mechanism might be related to regulation of cyclin D(1) protein expression and STAT(3) DNA binding activity.

Connective Tissue Growth Factor ; antagonists & inhibitors ; Cyclin D1 ; analysis ; DNA ; metabolism ; Fibroblasts ; cytology ; drug effects ; Humans ; Lipoxins ; pharmacology ; Lung ; cytology ; drug effects ; Receptors, Formyl Peptide ; genetics ; physiology ; Receptors, Lipoxin ; genetics ; physiology ; STAT3 Transcription Factor ; metabolism ; Transfection

HuaFu Shengji is the primary traditional Chinese medicine (TCM) therapy for treating chronic skin ulcer. The high activities of the protein enzyme in the wound fluids is one of the main cause of healing delay. In order to investigate the effect of TCM Zhuhong ointment for promoting wound healing. This research focused on its influence on matrix metalloproteinase (MMP) activities in wound fluids with TCM Yang syndromes, directly on the activated MMP-1,2 activities in vitro and on MMP-1,-2,-9 production by HSF. 8 wound fluid samples were collected, which were diagnosed Yang Syndromes in TCM. Wound fluid activities of MMP-2 and MMP-9 were measured by gelatin zymogram assay. MMP-1 and MMP-2 activities in vitro were measured by substrate cleavage. CCK-8 was used to observe the toxicity of Zhuhong ointment on HSF. MMP-1,-2,-9 production by HSF were detected by confocal microscope. Zhuhong ointment from 1 to 25 g x L(-1) obviously inhibited MMP-2 activity in wound fluid. When Zhuhong ointment was over 5 g x L(-1), it showed significantly inhibitory effect on wound fluid MMP-9 activity. In vitro study, when the mercury concentration was 320 mg x L(-1), Zhuhong ointment solution directly inhibited both MMP-1 activity and MMP-2. But mercury concentration from 0.51-2.56 mg x L(-1), it could activate MMP-1 activity, and from 0.51-64 mg x L(-1), activate MMP-2 activity instead. The mercury concentration when Zhuhong ointment saturated in DMEM was 39.6 mg x L(-1). When the mercury concentration was over 1.23 mg x L(-1), Zhuhong ointment showed toxicity to HSF. At 1.23, 0.62, 0.31 mg x L(-1) of mercury concentration, it increased MMP-1 expression by HSF, and at 1.23, 0.62 mg x L(-1), decreased MMP-2 expression. However, at 1.23, 0.62, 0.31 mg x L(-1), it decreased MMP-9 expression. At higher concentration, Zhuhong ointment can inhibit MMP-2, MMP-9 activities in wound fluid with dose-dependent way and show a direct inhibitory effect on activated MMP-1 and MMP-2 in vitro. But at a lower concentration, it showed two-way adjustment, with increased MMP-1, MMP-2 activities and its expression by HSF and decreased MMP-9 activity.
Body Fluids ; enzymology ; Cells, Cultured ; Dermatitis ; drug therapy ; enzymology ; physiopathology ; Drugs, Chinese Herbal ; pharmacology ; Fibroblasts ; drug effects ; enzymology ; physiology ; Humans ; Matrix Metalloproteinase 1 ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Wound Healing ; drug effects

PURPOSE: The present study was designed to determine whether rapamycin could inhibit transforming growth factor beta1 (TGF-beta1)-induced fibrogenesis in primary lung fibroblasts, and whether the effect of inhibition would occur through the mammalian target of rapamycin (mTOR) and its downstream p70S6K pathway. MATERIALS AND METHODS: Primary normal human lung fibroblasts were obtained from histological normal lung tissue of 3 patients with primary spontaneous pneumothorax. Growth arrested, synchronized fibroblasts were treated with TGF-beta1 (10 ng/mL) and different concentrations of rapamycin (0.01, 0.1, 1, 10 ng/mL) for 24 h. We assessed m-TOR, p-mTOR, S6K1, p-S6K1 by Western blot analysis, detected type III collagen and fibronectin secreting by ELISA assay, and determined type III collagen and fibronectin mRNA levels by real-time PCR assay. RESULTS: Rapamycin significantly reduced TGF-beta1-induced type III collagen and fibronectin levels, as well as type III collagen and fibronectin mRNA levels. Furthermore, we also found that TGF-beta1-induced mTOR and p70S6K phosphorylation were significantly down-regulated by rapamycin. The mTOR/p70S6K pathway was activated through the TGF-beta1-mediated fibrogenic response in primary human lung fibroblasts. CONCLUSION: These results indicate that rapamycin effectively suppresses TGF-beta1-induced type III collagen and fibronectin levels in primary human lung fibroblasts partly through the mTOR/p70S6K pathway. Rapamycin has a potential value in the treatment of pulmonary fibrosis.
Cells, Cultured ; Collagen Type III/metabolism ; Fibroblasts/*drug effects/metabolism/physiology ; Fibronectins/metabolism ; Humans ; Lung/cytology/drug effects ; Pulmonary Fibrosis/drug therapy ; Signal Transduction/drug effects ; Sirolimus/*pharmacology ; TOR Serine-Threonine Kinases/metabolism/physiology ; Transforming Growth Factor beta1/*antagonists & inhibitors/physiology