Effect of Matrix Metallopeptidase 13 on the Function of Mouse Bone Marrow-derived Dendritic Cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Dendritic cells are professional antigen-presenting cells found in an immature state in epithelia and interstitial space, where they capture antigens such as pathogens or damaged tissue. Matrix metallopeptidase 13 (MMP-13), a member of the collagenase subfamily, is involved in many different cellular processes and is expressed in murine bone marrow-derived dendritic cells (DCs). The function of MMP-13 in DCs is not well understood. Here, we investigated the effect of MMP-13 on DC maturation, apoptosis, and phagocytosis.</p><p><b>METHODS</b>Bone marrow-derived dendritic cells were obtained from C57BL/6 mice. One short-interfering RNA specific for MMP-13 was used to transfect DCs. MMP-13-silenced DCs and control DCs were prepared, and apoptosis was measured using real-time polymerase chain reaction and Western blotting. MMP-13-silenced DCs and control DCs were analyzed for surface expression of CD80 and CD86 and phagocytosis capability using flow cytometry.</p><p><b>RESULTS</b>Compared to the control DCs, MMP-13-silenced DCs increased expression of anti-apoptosis-related genes, BAG1 (control group vs. MMP-13-silenced group: 4.08 ± 0.60 vs. 6.11 ± 0.87, P = 0.008), BCL-2 (control group vs. MMP-13-silenced group: 7.54 ± 0.76 vs. 9.54 ± 1.29, P = 0.036), and TP73 (control group vs. MMP-13-silenced group: 4.33 ± 0.29 vs. 5.60 ± 0.32, P = 0.001) and decreased apoptosis-related genes, CASP1 (control group vs. MMP-13-silenced group: 3.79 ± 0.67 vs. 2.54 ± 0.39, P = 0.019), LTBR (control group vs. MMP-13-silenced group: 9.23 ± 1.25 vs. 6.24 ± 1.15, P = 0.012), and CASP4 (control group vs. MMP-13-silenced group: 2.07 ± 0.56 vs. 0.35 ± 0.35, P = 0.002). Protein levels confirmed the same expression pattern. MMP-13-silenced groups decreased expression of CD86 on DCs; however, there was no statistical difference in CD80 surface expression. Furthermore, MMP-13-silenced groups exhibited weaker phagocytosis capability.</p><p><b>CONCLUSION</b>These results indicate that MMP-13 inhibition dampens DC maturation, apoptosis, and phagocytosis.</p>

Role of pannexin 1 channels in cisplatin-induced apoptosis in I-10 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of pannexin 1 channels in cisplatin-induced apoptosis in I-10 cells and the mechanisms.</p><p><b>METHODS</b>MTT assay was used to assess the cytotoxicity of cisplatin (DDP) in I-10 cells. Annexin V/PI double staining and Hoechst 33258 fluorescence staining were employed to detect early- and late-stage apoptosis of the cells, respectively. Extracellular ATP level and intracellular IP3 level in the cells were detected using commercial detection kits.</p><p><b>RESULTS</b>I-10 cells exposed to both CBX (a pannexin 1 channel inhibitor) and DDP showed a higher cell viability compared with the cells exposed to DDP alone (P<0.01). CBX significantly decreased cisplatin-induced early-stage apoptosis (P<0.001) and late-stage apoptosis (P<0.01), and cause obvious reductions in extracellular ATP and intracellular IP3 levels during cisplatin-induced apoptosis (P<0.05).</p><p><b>CONCLUSION</b>Pannexin 1 channels participate in cisplatin-induced apoptosis in I-10 cells possibly through the ATP/IP3 pathway.</p>

Sodium valproate enhances doxorubicin cytotoxicity in breast cancer cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of sodium valproate, a histone deacetylase inhibitor, on the cytotoxicity of doxorubicin in breast cancer cells.</p><p><b>METHODS</b>Western blotting was used to assess Cx43 protein expression in breast cancer Hs578T cells exposed to doxorubicin and sodium valproate. MTT assay was used to determine the cytotoxicity of doxorubicin; annexin V/PI double staining and Hochest 33258 fluorescence staining were employed to detect doxorubicin-induced early and late apoptosis, respectively.</p><p><b>RESULTS</b>Western blotting showed that sodium valproate significantly increased Cx43 protein expression in Hs578T cells (P/0.01). The cells exposed to both sodium valproate and doxorubicin showed significantly lowered cell viability compared with the cells exposed to doxorubicin alone (P/0.01). Exposure to both sodium valproate and doxorubicin resulted in significantly increased early and late cell apoptosis rate compared with doxorubicin treatment alone (P/0.01).</p><p><b>CONCLUSION</b>sodium valproate can significantly enhance the cytotoxicity of doxorubicin and increase doxorubicin-induced apoptosis in breast cancer cells in vitro possibly by enhancing the gap junction function.</p>

Inhibition of gap junctional intercellular communication protects astrocytes from hypoxia/reoxygenation injury / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of inhibiting gap junctional intercellular communication on hypoxia/reoxygenation injury in astrocytes.</p><p><b>METHODS</b>Primary cultured cerebral cortical astrocytes of neonate rats were divided into normal control group, hypoxia reoxygenation injury group and 18-α-glycyrrhetinic acid and oleamide (gap junctional intercellular channel inhibitors) group. The gap junction intercellular communication was determined by Parachute assay. The viability of astrocyes was detected by MTT assay. The apoptosis of astrocytes were detected with annexin V/PI and Hoechst 33258 staining.</p><p><b>RESULTS</b>Compared with the normal control group, the gap junctional function of astrocytes was increased significantly in ischemia/reperfusion group (P<0.01), the surviving fraction of astrocytes decreased significantly (P<0.01) and its cell apoptosis ratio increased significantly (P<0.01). Compared with the ischemia/reperfusion group, the gap junctional function of astrocytes in18-α-glycyrrhetinic acid and oleamide group decreased significantly (P<0.01), the viability of astrocytes increased significantly (P<0.01), while cell apoptosis decreased significantly (P<0.01).</p><p><b>CONCLUSION</b>Inhibition of intercellular gap junction has protective effect against hypoxia/reoxygenation injury in astrocytes.</p>

Baicalein enhances the gap junction in the TM4 Sertoli cells of mice / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the effect of baicalein on the gap junction intercellular communication (GJIC) in the TM4 Sertoli cells of the mouse testis and its related mechanism.</p><p><b>METHODS</b>We measured the cytotoxicity of different concentrations of baicalein on the TM4 Sertoli cells in the mouse testis by MTT, detected the fluorescence transfer of the TM4 Sertoli cells by parachute assay, and determined the expression of the protein connexin 43 ( Cx43) in the baicalein-treated cells by Western blot and immunofluorescence assay.</p><p><b>RESULTS</b>Baicalein produced no obvious cytotoxicity on the TM4 Sertoli cells at the concentration below 60 µmol/L but significantly increased their GJIC at 0-20 µmol/L (P < 0.01). Western blot and immunofluorescence assay showed that 0-20 µmol/L baicalein remarkably elevated the expression of Cx43 in the TM4 cells (P < 0.01) and on the membrane of the TM4 cells.</p><p><b>CONCLUSION</b>Baicalein at the concentration of 0-20 µmol/L can significantly enhance GJIC in mouse TM4 Sertoli cells by increasing the expression of the Cx43 protein.</p>

Total flavonoids of litsea coreana decreases the cytotoxicity of oxaliplatin in TM3 Leydig cells via enhancing the function of gap junction / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the effects of total flavonoids of Litsea Coreana (TFLC) on the gap junction (GJ) intercellular communication in TM3 testicular Leydig cells and whether TFLC can reduce the cytotoxicity of oxaliplatin (OHP) in vitro.</p><p><b>METHODS</b>We detected the effect of TFLC on the dye spread of the in vitro cultured TM3 cells by parachute assay, observed changes in the expression of connexin 43 (Cx43) total protein in the TFLC-treated TM3 cells by Western blot, and determined the effects of TFLC on the expression of Cx43 on the membrane of the TM3 cells by immunofluorescence assay and on the cytotoxicity of OHP by MTT assay.</p><p><b>RESULTS</b>TFLC obviously enhanced the GJ function with the increasing of the TFLC concentration in the TM3 cells. Western blot and immunofluorescence assay confirmed that TFLC significantly enhanced the expression of Cx43 total protein and Cx43 expression on the membrane of the TM3 cells. MTT assay showed that at a high cell density (confluent with GJ formation), 20 microg/ml TFLC enhanced the GJ function of the TM3 cells and reduced the cytotoxicity of OHP (P < 0.05), while at a low density (preconfluent with no GJ formation), TFLC exhibited no effect on the cytotoxicity of OHP (P > 0.05).</p><p><b>CONCLUSION</b>TFLC increases the Cx43 expression and GJ function in normal TM3 Leydig cells, and the enhancement of GJ function reduces the cytotoxicity of OHP.</p>

PP2 enhances intercellular communication of gap junction in breast cancer Hs578T cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of Src kinase inhibitor PP2 on intercellular communication of gap junction in breast cancer cells.</p><p><b>METHODS</b>Cultured breast cancer Hs578T cells were treated with various concentrations of pp2 (0,1,2,4,8,16,32 μmol/L) for 24h. Cell growth was determined by MTT assay; dye spread in Hs578T cells was measured by Parachute assay; and the expression of Src kinase in Hs578T cells was detected by Western blot.</p><p><b>RESULTS</b>MTT assay showed that the survive rate of Hs578T cells treated with PP2 (1 ≊ 8 μmol/L) was 98% ± 3% ≊ 94 % ± 4%. Parachute assay showed that compared to control group the standard normalized dye spread rates of Hs578T cells treated with 1,2,4 and 8 μmol/L PP2 were 1.60 ± 0.08,2.00 ± 0.05,2.20 ± 0.05 and 2.70 ± 0.09,respectively (all P<0.01). Moreover,compared to control group at the same time points,the standard normalized dye spread of Hs578T cells treated with 8 μmol/L PP2 for 6,12 and 24 h were 1.4 ± 0.05,1.7 ± 0.06,and 2.2 ± 0.07,respectively (all P<0.01). Western blot showed that the expression ratios of Src kinase/β-actin of Hs578T cells treated with 1,2,4 and 8 μmol/L PP2 for 24 h were 0.93 ± 0.02,0.70 ± 0.09,0.66 ± 0.09 and 0.36 ± 0.10,which were significantly inhibited compared with control group (P<0.05 or 0.01). And the expression ratio of Src kinase/β-actin of Hs578T cells treated with 8 μmol/L PP2 for 6,12 and 24h was 0.82 ± 0.03,0.66 ± 0.08 and 0.59 ±0.09, which were all inhibited significantly compared to control group (P<0.01).</p><p><b>CONCLUSION</b>PP2 enhances the gap junction function in breast cancer Hs578T cells, which is probably related to the inhibition of Src kinase.</p>

Influence of Cx26/Cx32 gap junction channel on antineoplastic effect of etoposide in Hela cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the influence of Cx26/Cx32 gap junction channel on the antineoplastic effect of etoposide in Hela cervical cancer cells.</p><p><b>METHODS</b>Fluorescence trace was used to assay the gap junction intercellular communication mediated by Cx26/Cx32 in Hela cells and its functional modulation by the pharmacological agents (oleamide, retinoid acid). A standard colony-forming assay was applied to determine the cell growth-inhibiting effect of etoposide in Hela cells with functional modulation of the gap junction. Hoechst 33258 staining was used to assess the changes in etoposide-induced apoptosis of Hela cells with altered gap junction functions.</p><p><b>RESULTS</b>Oleamide markedly decreased while retinoid acid obviously increased the gap junction function in Hela cells. Standard colony-forming assay showed that etoposide produced a lowered antiproliferative effect in Hela cells with reduced gap junction and an increased antiproliferative effect in cells with enhanced gap junction function. In cells with a reduced gap junction function, etoposide induced a lowered apoptosis rate, which increased obviously in cells with an enhanced gap junction function.</p><p><b>CONCLUSION</b>The antineoplastic effect of etoposide is reduced in Hela cells with a decreased gap junction intercellular communication mediated by Cx26/Cx32 and is enhanced in cells with an increased gap junction intercellular communication.</p>