Expression of neonatal Fc receptor on human nephritis and rat nephritis models / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the expression of neonatal Fc receptor in podocytes in human nephritis and immune-induced rat nephritis models: anti-Thy1.1 nephritis and Heymann nephritis.</p><p><b>METHODS</b>Thirty-nine cases of renal biopsies were enrolled from September 2009 to February 2010, including 8 cases of minimal change disease, 4 cases of focal segmental glomerulosclerosis, 9 cases of membranous nephropathy, 12 cases of IgA nephropathy and 6 cases of lupus nephritis. Five normal kidney tissue samples adjacent to renal clear-cell carcinoma were served as normal controls. Laser capture microdissection and real-time RT-PCR were used to assess the expression level of FcRn mRNA in glomeruli of various glomerulonephritides, and immunohistochemistry (IHC) of FcRn by SuperVision method was performed. In addition, rat models of mesangial proliferative nephritis (anti-Thy1.1 nephritis) and passive membranous nephropathy (Heymann nephritis) were established and FcRn was examined in renal tissues by IHC.</p><p><b>RESULTS</b>The FcRn mRNA level in lupus nephritis was statistically higher than that of normal controls (P < 0.05). FcRn protein expression by IHC was seen in lupus nephritis (6/6), membranous nephropathy (6/9) and IgA nephropathy (7/12), significantly higher than that of normal controls (0/5), P < 0.05. Minimal change disease and focal segmental glomerular sclerosis showed minimal or none expression of FcRn (1/8, 0/4 respectively) and not statistically difference from that of normal controls. Furthermore, FcRn expression in podocytes was detected in rat anti-Thy1.1 (3/5) and Heymann nephritis models (2/7) but was not detected in normal controls.</p><p><b>CONCLUSIONS</b>Expression of FcRn in podocytes was up-regulated in immune-induced human nephritis and rat nephritis models of anti-Thy1.1 nephritis and Heymann nephritis. FcRn may play a role in the development of immune-induced glomerulonephritis.</p>

FAK/c-Src signaling pathway mediates the expression of cell surface HSP90 in cultured human prostate cancer cells and its association with their invasive capability / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expression of heat shock protein 90 (HSP90) on the cell surface of highly invasive human prostate cancer cells PC3 and its possible molecular mechanisms of its effect on cell invasion through analyzing FAK/Src signaling pathway.</p><p><b>METHODS</b>The expression of cell surface HSP90 on PC3 cells was studied by immunofluorescence staining and surface biotinylation assay respectively. A specific HSP90 antibody was used to inhibit the cell surface HSP90. In vitro cell invasion was assessed by modified Boyden chambers. Phosphorylated FAK on tyr 397, 576, 577 and 925, and phosphorylated c-Src on tyr 416 were examined by Western blot assay. The association between FAK and c-Src was analyzed by immunoprecipitation. The effects of FAK knockdown by siRNA or Src kinases inhibitor PP2, with or without anti-HSP90 antibody, on PC3 cell invasion were also evaluated.</p><p><b>RESULTS</b>A pool of HSP90 was detected on the cell surface of PC3 cells. A specific HSP90 antibody significantly retarded tumor cell invasion. Concomitant with this finding, targeting cell surface HSP90 significantly inhibited the phosphorylations of FAK and c-Src, and also the interactions between FAK and c-Src. FAK knockdown or PP2 dramatically suppressed cell invasion, however, anti-HSP90 antibody didn't further inhibit cell invasion.</p><p><b>CONCLUSIONS</b>Cell surface HSP90 promotes human prostate cancer cell invasion through a FAK/c-Src signaling, with may be a novel therapeutic target against metastatic tumors.</p>

Electron microscopic examination on 50 cases of prostatic needle biopsies / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the differences in ultrastructural findings between prostatic carcinoma and benign prostatic hypertrophy, and the various ultrastructural features seen in moderately to poorly differentiated prostatic carcinoma.</p><p><b>METHODS</b>Utrasound-guided needle biopsies were carried out in 50 clinically suspicious cases of prostatic carcinoma. For each case, one additional core was sampled from the most suspicious area, fixed in glutaraldehyde and examined under electron microscopy.</p><p><b>RESULTS</b>In the 50 cases of prostatic needle biopsies studied, there were a total of 42 cases with histologic findings of prostatic carcinoma. Thirty-one cases showed features corresponding to Gleason's score 3 to 5. In contrast to that seen in benign prostatic hypertrophy, the ultrastructural findings of the tumor cells commonly seen in prostatic carcinoma included the centrally located giant nucleoli, a direct contact with stroma, and formation of cytoplasmic microcyst. Occasionaly, there were mitotic figures seen, accompanying with fibromyxoid change of the peritumoural stroma. Amongst the 31 cases of Gleason's score 3 to 5 prostatic carcinoma, 29 cases (93.5%) demonstrated cytoplasmic prostasomes and storage vesicles. Similar to their counterparts in benign prostatic cells, prostasomes and storage vesicles in prostatic carcinoma cells were formed in the Golgi apparatus and released into the lumen by apocrine excretion and exocytosis.</p><p><b>CONCLUSIONS</b>Electron microscopy is helpful in distinguishing between benign and malignant prostatic lesions. Because of the high yield of prostasomes in moderately to poorly differentiated prostatic carcinoma, prostasomes may become a potential target for cancer immunotherapy and one of the useful diagnostic indices for delineating the prostatic origin of metastatic carcinoma.</p>

Apoptosis inducing factor mediates cisplatin-induced apoptosis of renal tubular epithelial cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the involvement of apoptosis inducing factor (AIF) in caspase-independent pathway mediating apoptosis of cultured renal tubular epithelial cells induced by cisplatin (CP).</p><p><b>METHODS</b>Western Blot analysis and real-time PCR were performed to detect cytosol AIF (cAIF), nuclear AIF (nAIF) and AIF mRNA expression in cultured renal epithelial cells (HK-2) treated with cisplatin (CP) at various concentrations (0 - 200 micromol/L) and time courses (0 - 12 h). Immunofluorescence analysis was used to detect the AIF protein distribution in HK-2 cells. Pan-caspase inhibitor (Z-VAD-FMK) and AIF-siRNA treatment, TUNEL and flow cytometer were used to measure the suppression of apoptosis induced by CP in HK-2 cells.</p><p><b>RESULTS</b>The expressions of cAIF, nAIF protein and AIF mRNA were all increased to some extent in HK-2 cells treated with CP at various concentrations and time points. cAIF expression was 2.3-fold (P < 0.05) increased after 25 micromol/L CP treatment for 12 h and 1.7-fold (P < 0.01) increased after 50 micromol/L CP treatment for 3 h, compared with that of control groups, and showed a concentration- and time-dependent increment. The nAIF expression reached a peak (4.3-fold increase) (P < 0.005) after 150 micromol/L CP treatment for 12 h and 3.7-fold incease (P < 0.05) after 50 micromol/L CP treatment for 9 h, compared with that of the 25 micromol/L group and 3 h group, respectively. The expression of nAIF was approximately consistent with cleaved-PARP expressive pattern. Real-time PCR showed that AIF mRNA increased gradually with prolonged treatment with 50 micromol/L CP and reached a peak at 9 h. Immunofluorescence assay showed AIF translocation from cytosol to nuclei in some cultured HK-2 cells treated with CP. Applying pan-caspase inhibitor (Z-VAD-FMK) and AIF-siRNA to CP-treated HK-2 cells, the apoptotic rates were decreased by 60.1% and 39.2%, respectively. The inhibitory effect on HK-2 cell apoptosis was even more significant with combination of both Z-VAD-FMK and AIF-siRNA.</p><p><b>CONCLUSION</b>The AIF activation and translocation to nuclei with the increment of its mRNA expression mediates CP-induced apoptosis of renal tubular epithelial cells in vitro. It may provide a new therapeutic target for protecting from nephrotoxciity of cisplatin.</p>

Pro-apoptotic effect of decorin on rat mesangial cells in vitro / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of over-expression of decorin (DCN) gene on apoptosis of cultured rat mesangial cells (MsC).</p><p><b>METHODS</b>PcDNA3.1A-DCN plasmid was transfected into cultured rat MsC by the induction of liposome and positive clones were selected by treating the cells with G418. The MsC clones stably expressing DCN (MsC/DCN) were confirmed by cellular immunofluorescence, reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot. The DCN-siRNA was used for blocking DCN expression in MsC/DCN, and was confirmed by Western blot. The apoptosis of MsC was assayed by flow cytometry and Hoechst staining. Expression of Caspase-3 was assayed by Western blot.</p><p><b>RESULTS</b>Positive clones with DCN over-expression were established. The apoptotic rate in MsC/DCN was (20.40 +/- 8.01)% and was much higher than the (2.07 +/- 0.99)% in MsC (P < 0.01). Some of the MsC/DCN cells showed typical morphologic changes of apoptosis. The protein expression of active Caspase-3 was also significantly increased in MsC/DCN compared to MsC (P < 0.01). DCN-siRNA transfection not only significantly blocked the expression of DCN and reduced the rate of apoptotic cells, but also down-regulated the expression of active Caspase-3.</p><p><b>CONCLUSIONS</b>Over-expression of DCN induces apoptosis of cultured rat MsC in vitro. This effect of DCN inducing apoptosis suggests a novel strategy for regulating the proliferation of MsC in glomerular diseases.</p>

Clinicopathologic analysis of 34 patients with microscopic polyangitis / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features of microscopic polyangitis (MPA), and to compare the differences in anti-neutrophil cytoplasmic autoantibody (ANCA)-positive and ANCA-negative patients, as well as in ANCA-positive cases with or without glomerular immunoglobulin deposition.</p><p><b>METHODS</b>Thirty-four biopsy-proven cases of MPA were retrieved from the archival files of the Department during the past 7 years. The clinicopathologic characteristics between ANCA-positive and negative patients, as well as between ANCA-positive cases with and without glomerular immunoglobulin deposition, were compared.</p><p><b>RESULTS</b>Amongst the 34 MPA patients studied, about one-fifth to one-half were accompanied by various extrarenal symptoms. Serum ANCA was positive in 26 patients (76.5%). A slight to moderate increase in urinary protein was demonstrated in 31 patients, while 3 patients had nephrotic syndrome. Elevated serum creatinine was detected in 32 cases. Renal biopsy revealed crescentic glomerulonephritis in 24 cases, focal segmental glomerulonephritis in 8 cases, vascular fibrinoid necrosis with inflammation in 7 cases, intimal thickening of arterioles in 24 cases, interstitial inflammatory cells, including neutrophil infiltration (21 cases), in 29 cases. Crescentic formation was more common in the ANCA-positive group than in the ANCA-negative group (P < 0.05). Amongst the 26 ANCA-positive cases, 10 had glomerular immunoglobulin deposits (including 1 case with IgA nephropathy). In general, these cases had a greater degree of proteinuria than those without glomerular immunoglobulin deposits (P < 0.05).</p><p><b>CONCLUSIONS</b>The diagnosis of MPA relies on histologic examination of renal biopsy and clinicopathologic correlation. Serum ANCA seems important for glomerular crescent formation. Glomerular immunoglobulin deposition may also play a significant role in the exacerbation of proteinuria.</p>

Effect of interferon-gamma on transforming growth factor beta/Smad signal pathway and expression of matrix metalloproteinase-2 and tissue inhibitors of matrix metalloproteinase-2 in cultured rat mesangial cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the effect of interferon-gamma (IFN-gamma) on the proliferation of mesangial cells (MsC) and transforming growth factor (TGF)-beta/Smad signal pathway, the mRNA and protein expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2), and to provide an experimental basis for IFN-gamma treatment of renal fibrosis.</p><p><b>METHODS</b>Cultured MsC were treated with IFN-gamma at different concentrations and the proliferation of MsC was examined by MTT. Protein and RNA samples were extracted from MsC at 0, 0.5, 1, 2, 4, 6, 12, 24 h after treated by 100 IU/ml IFN-gamma. The mRNA and protein expression of Smad3, Smad7, MMP-2 and TIMP-2 were analyzed by real-time RT-PCR and Western blot, respectively.</p><p><b>RESULTS</b>The expression of Smad7 mRNA and protein were promptly elevated at 0.5 hour after the IFN-gamma treatment and lasted for 6 hours, but the proliferation of MsC was not altered. The elevated expression of Smad3, MMP2 mRNA and proteins persisted after 6 hours, whereas the expression of TIMP-2 mRNA and protein decreased.</p><p><b>CONCLUSION</b>The therapeutic effect of IFN-gamma of renal fibrosis may be mediated by TGF-beta/smads signal pathway through up-regulation of MMP-2 expression, coupled with down-regulation of TIMP-2 expression.</p>

Changes of fibronectin and type IV collagen expression in cultured rat mesangial cells transfected with connective tissue growth factor expression vector / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the role of connective tissue growth factor (CTGF) in the development of glomerulosclerosis by experimental alteration of fibronectin (FN) and Type IV collagen (Col IV) expression in cultured rat mesangial cells (MsC).</p><p><b>METHODS</b>CTGF expression vector was transfected into MsC by Lipofectimine method. Protein and mRNA expression levels of CTGF, FN and Col IV were studied by Western blot and reverse transcription-polymerase chain reaction (RT-PCR) respectively.</p><p><b>RESULTS</b>Two of MsC clones (MCT-1 and MCT-2) with CTGF overexpression were successfully established and found to have significant increases of FN and Col IV at both protein and mRNA levels. Compared with the controls, the expression of FN protein and mRNA in the two clones were 3.2 times (P < 0.05) and 2.9 times (P < 0.05) higher respectively. The expression of Col IV protein and mRNA was 3.8 times (P < 0.01) and 2.4 times (P < 0.01) higher respectively.</p><p><b>CONCLUSION</b>CTGF up-regulates FN and Col IV expression in MsC and may play an important role in the development of glomerulosclerosis.</p>

Protective effect of amifostine on cisplatin-induced nephrotoxicity and its mechanism / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the sites and pattern of renal toxicity in rats treated with cisplatin and the protective effect of amifostine, and to understand whether Fas/FasL system is involved in cisplatin-induced nephrotoxicity.</p><p><b>METHODS</b>Forty-eight Sprague-Dawley rats were randomly divided into 3 groups: control group (0.9% saline solution), cisplatin group (6 mg/kg) and amifostine group (cisplatin 6 mg/kg + amifostine 200 mg/kg). Serum BUN and creatinine were measured by automatic biochemiscal analysis. Renal histopathological lesions were examined by light microscopy. TUNEL method was used for counting apoptotic cells. Immunohistochemistry and image analysis system were used for observing the expression of Fas/FasL system in renal tissues.</p><p><b>RESULTS</b>Compared with control group and amifostine group, serum BUN and creatinine were significantly elevated on day 3 (P < 0.05) and day 5 (P < 0.01 and P < 0.05, respectively), and recovered to normal on day 10. Severe necrosis and apoptosis of renal proximal tubular cells were revealed by elevated number of positively staining apoptotic cells examined by TUNEL method. Increased immunostaining intensity of Fas/FasL system in renal tissues in cisplatin-treated group was detected by immunohistochemistry and image analysis system.</p><p><b>CONCLUSION</b>Amifostine can reduce cisplatin-induced nephrotoxicity and its mechanism is probably associated with the suppression of Fas/FasL expression in renal tissues.</p>

Changes of fibronectin and type IV collagen expression in cultured rat mesangial cells transfected with Smad 2 vector / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the changes of fibronectin (FN) and type IV collagen (ColIV) expression in cultured rat mesangial cells (MsC) transfected with Smad 2 vector and to investigate the molecular mechanism of glomerular extracellular matrix accumulation in glomerulosclerosis via transforming growth factor-beta (TGF-beta)/Smad signal pathway.</p><p><b>METHODS</b>Smad 2 vector was transfected into MsC by calcium phosphate. Western blot analysis was used to detect Smad 2 protein. The expression of FN and ColIV proteins and their mRNAs was determined by Western blot and reverse transcriptase-polymerase chain reaction respectively.</p><p><b>RESULTS</b>Four MsC clones (T-12, T-31, T-35, T-40) with Smad 2 overexpression were established. The expression of FN and ColIV was significantly increased at mRNA and protein levels in two (T-12, T-31). Compared with controls, the expression of FN proteins and mRNAs in these two clones was 2.4 times (P < 0.05) and 2.7 times (P < 0.05) higher respectively. The expression of ColIV proteins and mRNAs was 2.9 times (P < 0.01) and 3.3 times (P < 0.01) higher respectively.</p><p><b>CONCLUSIONS</b>It is postulated that Smad 2 in TGF-beta/Smad signal pathway is important in promoting the accumulation of FN and ColIV in sclerotic glomeruli of diseased kidneys.</p>

Study on the signalling pathway of inhibitory effect of adreno-medullin on the growth of cultured glomerular mesangial cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Adrenomedullin (ADM), a potent hypotensive small peptide, was recently found to inhibit the proliferation of glomerular mesangial cells (MsC) in vitro and to attenuate glomerular lesions in vivo, however the mechanisms remain poorly understood. In this study, we attempted to elucidate them using molecular signal transduction.</p><p><b>METHODS</b>Cultured rat MsC were treated with ADM and several inhibitors of signalling molecules. Methyl thiazoleterazolium (MTT) assay and BrdU incorporation method were employed for examining MsC proliferation. Western blot analysis was used for detecting total mitogen activated protein kinases (t-MAPKs) and phosphorylated MAPKs (p-MAPKs) proteins.</p><p><b>RESULTS</b>ADM suppressed MsC proliferation in a concentration- and time-dependent fashion. This response was inhibited by ADM receptor antagonist CGRP8-37 and a potent protein kinase-A (PKA) inhibitor, H89. Forskolin, a direct adenylate cyclase activator, also significantly inhibited MsC proliferation. SB203580, a P38MAPK inhibitor, and U0126, a MEK inhibitor, both completely blocked ADM mediated responses in MsC. However, curcumin, a SAPK/JNK inhibitor, and GF109203X, a potent protein kinase-C (PKC) inhibitor, had no effect on MsC growth. Western blot analysis showed that ADM did not change the expression of t-MAPKs but increased p-SAPK/JNK and p-P38MAPK levels and decreased p-ERK level. These responses were inhibited by CGRP8-37. All these kinase phosphorylations, except for the increase in p-SAPK/JNK, could be stimulated using forskolin. In addition, only ADM mediated changes in ERK and P38MAPK phosphorylations were inhibited by H89. GF109203X did not affect ADM induced changes in three p-MAPKs expressions.</p><p><b>CONCLUSIONS</b>ADM inhibits MsC proliferation possibly through cAMP-PKA pathway. Both phosphorylations of ERK and P38MAPK pathways were necessary in mediating the antiproliferative response of ADM. It does not preclude the involvement of cAMP independent pathways in the ADM mediated responses.</p>

Significance of MMP-2 and TIMP-2 mRNA expressions on glomerular cells in the development of glomerulosclerosis / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To study the expressions of MMP-2 and TIMP-2 mRNA on cultured rat mesangial cells (MsC) and in human diseased glomeruli, and to explore their significance in the development of glomerulosclerosis.</p><p><b>METHODS</b>The expressions of MMP-2, TIMP-2, and Col IV mRNA on cultured rat MsC stimulated by IL-1 or/and TGF-beta1 were investigated through Northern blot analysis. The levels of MMP-2 and TIMP-2 mRNA expressions and immunoreactivity of PCNA and Col IV in human diseased glomeruli from renal biopsies of lupus nephritis (LN) patients were examined by in situ hybridization and immunohistochemistry, respectively.</p><p><b>RESULTS</b>The levels of MMP-2, TIMP-2, and Col IV mRNA expressions were markedly increased on cultured rat MsC stimulated by IL-1 or/and TGF-beta1. Meanwhile, upregulation of MMP-2 and TIMP-2 mRNA expressions was confirmed in diseased glomeruli from patients with various subtypes of LN, and was closely related to the positive cell number of PCNA presentation and deposition of Col IV in glomeruli.</p><p><b>CONCLUSION</b>The results suggest that the over-expressions of MMP-2 and TIMP-2 mRNA on glomerular cells might play a critical role in the development of glomerulosclerosis.</p>

Role of hepatitis B virus infection in pathogenesis of IgA nephropathy / 中华预防医学杂志

<p><b>OBJECTIVE</b>To clarify the relationship between hepatitis B virus (HBV) infection and IgA nephropathy (IgAN).</p><p><b>METHODS</b>HBV antigen (HBAg) in renal tissues of the patients with IgAN was detected by immunohistochemical technique, the carrier status and localization of HBV DNA in renal tissues were determined by Southern blot analysis and in situ hybridization.</p><p><b>RESULTS</b>Serum HBsAg was detected in 18 of the 100 patients with IgAN (18%), HBAg was detected in 31 of 100 patients (31%) in their renal tissue and in 20 of 31 patients (65%) in their glomeruli, and both HBsAg and HBcAg were detected in 10 of 31 patients (32%), respectively. HBcAg was also found in tubular epithelia (45%, 14/31) and renal interstitium (6%, 2/31), respectively. Five of six cases were proved to be positive of integrated-form HBV DNA in their renal tissue by Southern blot analysis. In situ hybridization demonstrated that HBV DNA was 8/8 and 6/8 positive in their renal tubules and glomeruli of all eight specimens, localized in the nucleus of tubular epithelial cells, glomerular mesangial cells, as well as infiltrated interstitial lymphocytes.</p><p><b>CONCLUSION</b>HBV infection closely related with IgAN and HBV infection might be involved in pathogenesis of IgAN.</p>

The antagonistic effect on anti-thy-1 serum-induced nephritis of rats injected by decorin-transfected mesangial cells vector / 中华病理学杂志

<p><b>OBJECTIVES</b>To inject decorin-transfected mesangial cells (MsC) vector into the kidneys of rats with anti-thy-1 serum-induced nephritis via left renal artery and observe the survival condition of MsC vector and its influence on glomerular lesions in rats with anti-thy-1 serum induced nephritis.</p><p><b>METHODS</b>Rat mesangio-proliferative glomerulonephritis was established by tail intravenous injection with rabbit anti-thy-1 serum (ATS). Decorin-transfected MsC was injected into rat kidneys via left renal artery. Primary culture, immunostaining for BrdU and decorin of transfected MsC lines were performed to observe their survival. Immunohistochemistry with image analysis was performed to detect the expression of BrdU, alpha-SMA, decorin, TGF-beta1, FN and ColIV in diseased glomeruli.</p><p><b>RESULTS</b>Rat anti-thy-1 serum-induced nephritis identified by pathological examination was successfully established by injecting rabbit ATS, and decorin transfected MsC vector was transfused to rat glomeruli via left renal artery. The active growth and positive expressions of BrdU and decorin proteins on the nuclei and cytoplasms of ex vivo MsC were observed respectively. TGF-beta1, FN, ColIV expressions in diseased glomeruli of rats with ATS nephritis were decreased significantly at day 4 (TGF-beta1, P < 0.05) and day 2 (FN and ColIV, P < 0.01) respectively, compared to uninjected kidneys.</p><p><b>CONCLUSIONS</b>MsC vector is successfully transferred to the glomeruli of experimental rats via left renal artery injection with no affect on cell survival. Decorin protein is expressed on the transfected MsC and shows antagonistic effect on the glomerular lesions of ATS rats. It suggests that the use of ex vivo MsC vector system can provide useful experimental basis for gene therapy of kidney disease in animal model.</p>

Changes of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 expressions on cultured rat mesangial cells transfected with Smad 7 vector / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) expressions in the cultured rat mesangial cells (MsC) transfected with Smad 7 vector and to elucidate the mechanism of Smad 7 in blocking tissue fibrosis.</p><p><b>METHODS</b>Lipofectin method was used to transfect Smad 7 vector into MsC. Western blot and RT-PCR analyses were then used to detect Smad 7 protein and mRNA expression levels. The expressions of MMP-2 and TIMP-2 were determined by Western blot, RT-PCR and zymography assay.</p><p><b>RESULTS</b>Two MsC clones (S-22, S-26) with Smad 7 overexpression were successfully established. The two clones showed an increased expression of MMP-2 protein and enhanced enzyme activity. The expressions of TIMP-2 protein and mRNA however were suppressed.</p><p><b>CONCLUSIONS</b>It is possible that Smad 7 can alleviate the development of tissue fibrosis by upregulating the expression of MMP-2 and downregulating the expression of TIMP-2 in mesangial cells.</p>

Effect of transforming growth factor beta1/Smad signaling pathway on the expression and enzymatic activity of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 in cultured rat mesangial cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore the effect of transforming growth factor (TGF) beta1/Smad signaling pathway on the expression and enzymatic activity of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) in cultured rat mesangial cells (MsC).</p><p><b>METHODS</b>Lipofectin method was used to transfect Smad 2, Smad 3 and Smad 7 vectors into MsC; and immunofluorescence, RT-PCR and Western blot analysis were used to detect their transfection efficiency. The expression and enzymatic activity of MMP-2 and TIMP-2 were determined by Western blot, zymography or reverse zymography assay.</p><p><b>RESULTS</b>MsC transfected with Smad 2 gene showed slightly increased expression and enzymatic activity of both MMP-2 and TIMP-2, which was more obvious upon stimulation by TGF-beta1. MsC transfected with Smad 3 gene showed a slight upregulation of TIMP-2 expression and its enzymatic activity, which was enhanced after TGF-beta1 stimulation. There was however no change in MMP-2 expression and its enzymatic activity. On the other hand, MsC transfected with Smad 7 gene showed a decrease in MMP-2 and TIMP-2 expression and enzymatic activity, which was especially obvious after stimulation by TGF-beta1.</p><p><b>CONCLUSIONS</b>TGF-beta1/Smad signaling pathway may play an important role in the pathogenesis of glomerulosclerosis, probably via MMP-2 and TIMP-2 expression and the associated enzymatic activity.</p>