AIM:To study the effect of zymosan,a ligand found on the surface of fungi,on gap junctional intercellular communication(GJIC)in cultured human corneal fibroblasts(HCFs).METHODS:Zymosan was added to the medium of cultu...AIM:To study the effect of zymosan,a ligand found on the surface of fungi,on gap junctional intercellular communication(GJIC)in cultured human corneal fibroblasts(HCFs).METHODS:Zymosan was added to the medium of cultured HCFs with or without the administration of mitogenactivated protein kinase(MAPK)inhibitors or the inhibitor kappa B kinase 2(IKK2)inhibitor IV.The protein and m RNA levels of connexin 43(Cx43)in HCFs were measured by Western blot,immunofluorescence,and quantitative reverse transcription-polymerase chain reaction(q RT-PCR)analyses.The GJIC activity was tested using a dye-coupling assay.RESULTS:The reduction of Cx43 protein and m RNA levels as well as a significant decrease in GJIC activity were observed in cultured HCFs when zymosan was added into the culture medium.Compared with controls(no zymosan),the protein level of Cx43 was reduced by 45%and 54%in the presence of zymosan at 200 and 600μg/m L,respectively(P<0.05);and it was reduced by 45%,48%,and 75%in the presence of zymosan(600μg/m L)for 24,36,and 48 h,respectively(P<0.05).The m RNA expression of Cx43 was reduced by 98%in the presence of zymosan(P<0.05).The effects of zymosan on Cx43 expression and GJIC activity were attenuated by the administration of PD98059[an extracellular signal-regulated kinase(ERK)signaling inhibitor](P<0.05),c-Jun NH2-terminal kinase(JNK)inhibitor II(P<0.05),and IKK2 inhibitor IV(P<0.05).CONCLUSION:Zymosan inhibits the activity of GJIC in cultured HCFs.This effect is likely regulated via the nuclear factor-κB(NF-κB),MAPK/ERK,and JNK signaling pathways.The inhibitory effects of zymosan on Cx43 expression and GJIC activity in HCFs may induce damage of corneal stroma during corneal fungal infection.展开更多
To illuminate the regulating effect of all trans retinoic acid (ATRA ) on gap junctional intercellular communication (GJIC) and connexin 43 (Cx43) ge ne expression in glioma cells, which is tissue and organ specific. ...To illuminate the regulating effect of all trans retinoic acid (ATRA ) on gap junctional intercellular communication (GJIC) and connexin 43 (Cx43) ge ne expression in glioma cells, which is tissue and organ specific. Method. Rat C6 glioma cells were exposed to ATRA at a concentration of 1, 10, 10 0 μmol/L respectively, and the GJIC function of the cells was examined with scr ape loading dye transfer assay 24 hours, 48 hours and 72 hours after ATRA treat ment. The effect of ATRA on Cx43 gene expression was measured with semiquantitat ive reverse transcription polymerase chain reaction (RT PCR) 24 hours after ATR A exposure. Results. The GJIC function of C6 glioma cells was significantly increased by ATR A at each concentration applied. The dye passed 4 to 5 rows of cells from the sc raping edge in ATRA treated cells, but only 1 or 2 rows in the control. The augm ent effect was observed 24 hours after each concentration ATRA treatment, and la sted till 72 hours after treatment with 1μmol/L and 10μmol/L ATRA. Forty eigh t hours after exposed to 100μmol/L ATRA, the enhancement of GJIC was less obvi ous. There was no significant increase induced by ATRA on the transcription of C x43 gene, as demonstrated by semiquantitative RT PCR. Conclusion. ATRA turned out to be a potent enhancer on GJIC function in C6 gliom a cells, and the enhancement effect was most probable at post transcriptional l evel.展开更多
Objective: To investigate the expression of myocardium connexin 43(Cx43) in late exercise preconditioning(LEP) cardioprotection. Methods: Eight-week-old adult male Sprague Dawley rats were randomly assigned into four ...Objective: To investigate the expression of myocardium connexin 43(Cx43) in late exercise preconditioning(LEP) cardioprotection. Methods: Eight-week-old adult male Sprague Dawley rats were randomly assigned into four groups(n=8). Myocardial injury was judged in accordance with serum levels of c Tn and NT-pro BNP as well as hematoxylin basicfuchsin picric acid staining of myocardium. Cx43 m RNA was detected by in situ hybridization and qualified by real-time fluorescence quantitative PCR. Cx43 protein was localized by immunohistochemistry and its expression level was determined by western blotting. Results: The LEP obviously attenuated the myocardial ischemia/hypoxia injury caused by exhaustive exercise. There was no significant difference of Cx43 m RNA level between the four groups. Cx43 protein level was decreased significantly in group EE(P<0.05). However, LEP produced a significant increase in Cx43 protein level(P<0.05), and the decreased Cx43 protein level in exhaustive exercise was significantly up-regulated by LEP(P<0.05). Conclusions: LEP protects rat heart against exhaustive exercise-induced myocardial injury by up-regulating the expression of myocardial Cx43.展开更多
The experimental model of traumatic brain injury was established in Sprague-Dawley rats according to Feeney’s free falling method.The brains were harvested at 2,6 and 24 hours,and at 3 and 5days after injury.Changes ...The experimental model of traumatic brain injury was established in Sprague-Dawley rats according to Feeney’s free falling method.The brains were harvested at 2,6 and 24 hours,and at 3 and 5days after injury.Changes in brain water content were determined using the wet and dry weights.Our results showed that water content of tissue significantly increased after traumatic brain injury,and reached minimum at 24 hours.Hematoxylin-eosin staining revealed pathological impairment of brain tissue at each time point after injury,particularly at 3 days,with nerve cell edema,degeneration,and necrosis observed,and the apoptotic rate significantly increased.Immunohistochemistry and western blot analysis revealed that the expression of occludin at the injured site gradually decreased as injury time advanced and reached a minimum at 3 days after injury;the expression of connexin 43 gradually increased as injury time advanced and reached a peak at 24 hours after injury.The experimental findings indicate that changes in occludin and connexin 43 expression were consistent with the development of brain edema,and may reflect the pathogenesis of brain injury.展开更多
·AIM:To investigate the expression of connexin 43 and epithelial cadherin (E-cadherin) in choroidal melanoma,to explore the clinical and pathological implications of expression of these proteins,and to determine ...·AIM:To investigate the expression of connexin 43 and epithelial cadherin (E-cadherin) in choroidal melanoma,to explore the clinical and pathological implications of expression of these proteins,and to determine their relations with malignant features.·METHODS:The expression of connexin 43 and E-cadherin in choroidal melanoma were detected by immunohist-ochemistry and correlated with clinicopathological features.·RESULTS:Positive rates of connexin 43 in choroidal melanomas and benign pigmented nevus tissues were 75% and 40% respectively with significant differences between the two groups (χ2=5.607,P =0.009).Positive rates of E-cadherin in choroidal melanomas and benign pigmented nevus tissues were 40￡$ and 75% respectively with significant differences between the two groups (χ2=5.214,P=0.010).Significant overexpression of connexin 43 and reduction of E-cadherin expression was associated with the invasion to the sclera,and there were respectively significant differences between without and with scleral invasion groups (χ2=2.880,P=0.040;χ2=2.778,P =0.046).Overexpression of connexin 43 were correlated with tumor cell types and the expression of connexin 43 and E-cadherin may be correlated with each other.·CONCLUSION:The increased expression of connexin 43 and the decreased expression of E-cadherin may be involved in the process of invasion of choroidal melanoma.The overepression of connexin 43 and reduction of E-cadherin may contribute to the development of choroidal melanoma.·展开更多
Objectives To study the effects of angiotensin II, as a mediator of cardiac hypertrophy, on expression of connexin 43 (Cx43) in cultured neonatal rat ventricular myocytes and correlation of expression of Cx43 and card...Objectives To study the effects of angiotensin II, as a mediator of cardiac hypertrophy, on expression of connexin 43 (Cx43) in cultured neonatal rat ventricular myocytes and correlation of expression of Cx43 and cardiomyocyte hypertrophy. Methods Cardiomyocytes were isolated from newborn SD rats. Angiotensin II was added into the media to induce myocyte hypertrophy. Cultures were exposed to 10～6 mol/L angiotensin II for 72 h, Cx43 expression was characterized by RT-PCR and Immunofluorescence methods. Results Immunofluorescence analysis revealed decreased Cx43 immunoreactivity in cells treated for 72 h with angiotensin II. RT-PCR analysis demonstrated there was an obvious decrease of Cx43 mRNA level in cells exposed to angiotensin II for 72 h. The changes of expression of connexin 43 were related to its entrance into S phase of the cell cycle. Cultured neonatal rat cardiomyocytes were exposed for 72 h to increase concentrations of angiotensin II (1.0×10-9～1.0×10-6mol/L), resulting in significantly decreased Cx43 expression. Conclusions Angiotensin II leads to a concentration-dependent decrease in Cx43 protein in cultured neonatal rat ventricular myocytes by decreasing Cx43 mRNA synthesis. Signal transduction pathways activated by angiotensin II under pathophysiologic conditions of cardiac hypertrophy could initiate remodeling of gap junctions.展开更多
Peripheral nerve injury downregulates connexin43(Cx43)expression in spinal astrocytes.Therefore,restoration of spinal astrocyte Cx43 expression to normal levels could lead to the reduction of nerve injury-induced pain...Peripheral nerve injury downregulates connexin43(Cx43)expression in spinal astrocytes.Therefore,restoration of spinal astrocyte Cx43 expression to normal levels could lead to the reduction of nerve injury-induced pain.It has been shown that inhibitors of phosphodiesterase-4(PDE4),an enzyme catalyzing the hydrolysis of cyclic AMP(cAMP),reverse mechanical pain in mice with neuropathic pain.However,the antinociceptive mechanism remains unclear.In the present study,we evaluated the antinociceptive effect of PDE4 inhibitors and demonstrated a novel mechanism by which PDE4 mediates nociception via Cx43 in spinal astrocytes.Methods:The effects of PDE4 inhibitors on neuropathic pain and Cx43 expression in spinal astrocytes were evaluated in mice with partial sciatic nerve ligation(PSNL).Results:Single or repeated,intraperitoneal treatment with the selective PDE4 inhibitor rolipram or roflumilast of mice with PSNL significantly reduced mechanical hypersensitivity.This was mimicked by intrathecal administration of rolipram or roflumilast.In addition,repeated intrathecal treatment with rolipram or roflumilast of mice with PSNL completely prevented the downregulation of Cx43 expression in the spinal dorsal horn.Conclusion:The results suggest that PDE4 inhibitors ameliorate neuropathic pain,which is mediated by a spinal mechanism through the restoration of spinal Cx43 expression.展开更多
Background: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects mi...Background: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. Methods: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca^(2+)-related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. Results: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca ^(2+ )is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. Conclusions: Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.展开更多
基金Supported by the National Natural Science Foundation of China(No.81770889)the Natural Science Foundation of Guangdong Province(No.2018A030313428)the Zhuhai Science and Technology Program(No.20191210E030077)。
文摘AIM:To study the effect of zymosan,a ligand found on the surface of fungi,on gap junctional intercellular communication(GJIC)in cultured human corneal fibroblasts(HCFs).METHODS:Zymosan was added to the medium of cultured HCFs with or without the administration of mitogenactivated protein kinase(MAPK)inhibitors or the inhibitor kappa B kinase 2(IKK2)inhibitor IV.The protein and m RNA levels of connexin 43(Cx43)in HCFs were measured by Western blot,immunofluorescence,and quantitative reverse transcription-polymerase chain reaction(q RT-PCR)analyses.The GJIC activity was tested using a dye-coupling assay.RESULTS:The reduction of Cx43 protein and m RNA levels as well as a significant decrease in GJIC activity were observed in cultured HCFs when zymosan was added into the culture medium.Compared with controls(no zymosan),the protein level of Cx43 was reduced by 45%and 54%in the presence of zymosan at 200 and 600μg/m L,respectively(P<0.05);and it was reduced by 45%,48%,and 75%in the presence of zymosan(600μg/m L)for 24,36,and 48 h,respectively(P<0.05).The m RNA expression of Cx43 was reduced by 98%in the presence of zymosan(P<0.05).The effects of zymosan on Cx43 expression and GJIC activity were attenuated by the administration of PD98059[an extracellular signal-regulated kinase(ERK)signaling inhibitor](P<0.05),c-Jun NH2-terminal kinase(JNK)inhibitor II(P<0.05),and IKK2 inhibitor IV(P<0.05).CONCLUSION:Zymosan inhibits the activity of GJIC in cultured HCFs.This effect is likely regulated via the nuclear factor-κB(NF-κB),MAPK/ERK,and JNK signaling pathways.The inhibitory effects of zymosan on Cx43 expression and GJIC activity in HCFs may induce damage of corneal stroma during corneal fungal infection.
文摘To illuminate the regulating effect of all trans retinoic acid (ATRA ) on gap junctional intercellular communication (GJIC) and connexin 43 (Cx43) ge ne expression in glioma cells, which is tissue and organ specific. Method. Rat C6 glioma cells were exposed to ATRA at a concentration of 1, 10, 10 0 μmol/L respectively, and the GJIC function of the cells was examined with scr ape loading dye transfer assay 24 hours, 48 hours and 72 hours after ATRA treat ment. The effect of ATRA on Cx43 gene expression was measured with semiquantitat ive reverse transcription polymerase chain reaction (RT PCR) 24 hours after ATR A exposure. Results. The GJIC function of C6 glioma cells was significantly increased by ATR A at each concentration applied. The dye passed 4 to 5 rows of cells from the sc raping edge in ATRA treated cells, but only 1 or 2 rows in the control. The augm ent effect was observed 24 hours after each concentration ATRA treatment, and la sted till 72 hours after treatment with 1μmol/L and 10μmol/L ATRA. Forty eigh t hours after exposed to 100μmol/L ATRA, the enhancement of GJIC was less obvi ous. There was no significant increase induced by ATRA on the transcription of C x43 gene, as demonstrated by semiquantitative RT PCR. Conclusion. ATRA turned out to be a potent enhancer on GJIC function in C6 gliom a cells, and the enhancement effect was most probable at post transcriptional l evel.
基金supported by Chinese Postdoctoral Science Foundation(No.2014N560538)Hainan Province Colleges and Universities Scientific Research Project(No.Hnky2015-34)Project of Natural Science Foundation of Hainan Province(314090)
文摘Objective: To investigate the expression of myocardium connexin 43(Cx43) in late exercise preconditioning(LEP) cardioprotection. Methods: Eight-week-old adult male Sprague Dawley rats were randomly assigned into four groups(n=8). Myocardial injury was judged in accordance with serum levels of c Tn and NT-pro BNP as well as hematoxylin basicfuchsin picric acid staining of myocardium. Cx43 m RNA was detected by in situ hybridization and qualified by real-time fluorescence quantitative PCR. Cx43 protein was localized by immunohistochemistry and its expression level was determined by western blotting. Results: The LEP obviously attenuated the myocardial ischemia/hypoxia injury caused by exhaustive exercise. There was no significant difference of Cx43 m RNA level between the four groups. Cx43 protein level was decreased significantly in group EE(P<0.05). However, LEP produced a significant increase in Cx43 protein level(P<0.05), and the decreased Cx43 protein level in exhaustive exercise was significantly up-regulated by LEP(P<0.05). Conclusions: LEP protects rat heart against exhaustive exercise-induced myocardial injury by up-regulating the expression of myocardial Cx43.
基金supported by the Natural Science Foundation of Guangdong Province,No.10151600101000002
文摘The experimental model of traumatic brain injury was established in Sprague-Dawley rats according to Feeney’s free falling method.The brains were harvested at 2,6 and 24 hours,and at 3 and 5days after injury.Changes in brain water content were determined using the wet and dry weights.Our results showed that water content of tissue significantly increased after traumatic brain injury,and reached minimum at 24 hours.Hematoxylin-eosin staining revealed pathological impairment of brain tissue at each time point after injury,particularly at 3 days,with nerve cell edema,degeneration,and necrosis observed,and the apoptotic rate significantly increased.Immunohistochemistry and western blot analysis revealed that the expression of occludin at the injured site gradually decreased as injury time advanced and reached a minimum at 3 days after injury;the expression of connexin 43 gradually increased as injury time advanced and reached a peak at 24 hours after injury.The experimental findings indicate that changes in occludin and connexin 43 expression were consistent with the development of brain edema,and may reflect the pathogenesis of brain injury.
文摘·AIM:To investigate the expression of connexin 43 and epithelial cadherin (E-cadherin) in choroidal melanoma,to explore the clinical and pathological implications of expression of these proteins,and to determine their relations with malignant features.·METHODS:The expression of connexin 43 and E-cadherin in choroidal melanoma were detected by immunohist-ochemistry and correlated with clinicopathological features.·RESULTS:Positive rates of connexin 43 in choroidal melanomas and benign pigmented nevus tissues were 75% and 40% respectively with significant differences between the two groups (χ2=5.607,P =0.009).Positive rates of E-cadherin in choroidal melanomas and benign pigmented nevus tissues were 40￡$ and 75% respectively with significant differences between the two groups (χ2=5.214,P=0.010).Significant overexpression of connexin 43 and reduction of E-cadherin expression was associated with the invasion to the sclera,and there were respectively significant differences between without and with scleral invasion groups (χ2=2.880,P=0.040;χ2=2.778,P =0.046).Overexpression of connexin 43 were correlated with tumor cell types and the expression of connexin 43 and E-cadherin may be correlated with each other.·CONCLUSION:The increased expression of connexin 43 and the decreased expression of E-cadherin may be involved in the process of invasion of choroidal melanoma.The overepression of connexin 43 and reduction of E-cadherin may contribute to the development of choroidal melanoma.·
文摘Objectives To study the effects of angiotensin II, as a mediator of cardiac hypertrophy, on expression of connexin 43 (Cx43) in cultured neonatal rat ventricular myocytes and correlation of expression of Cx43 and cardiomyocyte hypertrophy. Methods Cardiomyocytes were isolated from newborn SD rats. Angiotensin II was added into the media to induce myocyte hypertrophy. Cultures were exposed to 10～6 mol/L angiotensin II for 72 h, Cx43 expression was characterized by RT-PCR and Immunofluorescence methods. Results Immunofluorescence analysis revealed decreased Cx43 immunoreactivity in cells treated for 72 h with angiotensin II. RT-PCR analysis demonstrated there was an obvious decrease of Cx43 mRNA level in cells exposed to angiotensin II for 72 h. The changes of expression of connexin 43 were related to its entrance into S phase of the cell cycle. Cultured neonatal rat cardiomyocytes were exposed for 72 h to increase concentrations of angiotensin II (1.0×10-9～1.0×10-6mol/L), resulting in significantly decreased Cx43 expression. Conclusions Angiotensin II leads to a concentration-dependent decrease in Cx43 protein in cultured neonatal rat ventricular myocytes by decreasing Cx43 mRNA synthesis. Signal transduction pathways activated by angiotensin II under pathophysiologic conditions of cardiac hypertrophy could initiate remodeling of gap junctions.
文摘Peripheral nerve injury downregulates connexin43(Cx43)expression in spinal astrocytes.Therefore,restoration of spinal astrocyte Cx43 expression to normal levels could lead to the reduction of nerve injury-induced pain.It has been shown that inhibitors of phosphodiesterase-4(PDE4),an enzyme catalyzing the hydrolysis of cyclic AMP(cAMP),reverse mechanical pain in mice with neuropathic pain.However,the antinociceptive mechanism remains unclear.In the present study,we evaluated the antinociceptive effect of PDE4 inhibitors and demonstrated a novel mechanism by which PDE4 mediates nociception via Cx43 in spinal astrocytes.Methods:The effects of PDE4 inhibitors on neuropathic pain and Cx43 expression in spinal astrocytes were evaluated in mice with partial sciatic nerve ligation(PSNL).Results:Single or repeated,intraperitoneal treatment with the selective PDE4 inhibitor rolipram or roflumilast of mice with PSNL significantly reduced mechanical hypersensitivity.This was mimicked by intrathecal administration of rolipram or roflumilast.In addition,repeated intrathecal treatment with rolipram or roflumilast of mice with PSNL completely prevented the downregulation of Cx43 expression in the spinal dorsal horn.Conclusion:The results suggest that PDE4 inhibitors ameliorate neuropathic pain,which is mediated by a spinal mechanism through the restoration of spinal Cx43 expression.
基金supported by the National Key R&D Program of China(2022YFA1103300)the National Natural Science Foundation of China(81873424,81570097)+2 种基金the Natural Science Foundation of Chongqing Innovation Group Science Program(cstc2021jcyjcxttX0001)Clinical Medical Research Project of Army Medical University(2018XLC1006)and Translational Research Grant of NCRCH(2020ZKZC02).
文摘Background: Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown. Methods: Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca^(2+)-related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance. Results: Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca ^(2+ )is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments. Conclusions: Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.
