Progress in molecular signal pathway of dental fluorosis / 中华地方病学杂志

Dental fluorosis is a manifestation of chronic oral fluorosis caused by excessive fluoride intake in childhood. At present, the molecular mechanism of dental fluorosis is still unclear. Ameloblasts are the most sensitive cells to fluoride in tooth tissue. Fluoride affects the proliferation and secretion of ameloblasts through the role of key molecules in the molecular signal pathways, leading to the formation of dental fluorosis. This paper reviews the relationship between the molecular signal pathways [mitogen-activated protein kinase (MAPK), transforming growth factor-β (TGF-β)/Smad, Wnt, Foxo1/Runx2], stress pathways (endoplasmic reticulum stress and oxidative stress) and the occurrence of dental fluorosis in recent years, in order to deeply understand the pathogenesis of dental fluorosis at the molecular level, and provide new ideas for the prevention and treatment of dental fluorosis.

Estradiol inhibits differentiation of mouse macrophage into a pro-inflammatory phenotype by upregulating the IRE1α-XBP1 signaling axis / 南方医科大学学报

OBJECTIVE@#To explore the mechanism by which estradiol modulates the immunophenotype of macrophages through the endoplasmic reticulum stress pathway.@*METHODS@#Peritoneal macrophages isolated from C57 mice were cultured in the presence of 60 ng/mL interferon-γ (IFN-γ) followed by treatment with estradiol (1.0 nmol/L) alone, estradiol with estrogen receptor antagonist (Acolbifene, 4 nmol/L), estradiol with IRE1α inhibitor (4 μ 8 C), or estradiol with IRE1α agonist. After the treatments, the expression levels of MHC-Ⅱ, iNOS and endoplasmic reticulum stress marker proteins IRE1α, eIF2α and ATF6 in the macrophages were detected with Western blotting, and the mRNA levels of TGF-β, IL-6, IL-10 and TNF-α were detected with RT-PCR.@*RESULTS@#Estrogen treatment of the macrophages significantly decreased the expressions of M1-related proteins MHC-Ⅱ (P=0.021) and iNOS (P < 0.001) and the mRNA expressions of TNF-α (P=0.003) and IL-6 (P=0.004), increased the mRNA expression of TGF-β (P=0.002) and IL-10 (P=0.008), and up-regulated the protein expressions of IRE1α (P < 0.001) and its downstream transcription factor XBP-1 (P < 0.001). Addition of the estrogen inhibitor obviously blocked the effect of estrogen. Compared with estrogen treatment alone, combined treatment of the macrophages with estrogen and the IRE1α inhibitor 4 μ 8 C significantly up-regulated the protein expressions of MHC-Ⅱ (P=0.002) and iNOS (P=0.003) and the mRNA expressions of TNF-α (P=0.003) and IL-6 (P=0.024), and obviously down-regulated the mRNA expression of TGF-β (P < 0.001) and IL-10 (P < 0.001); these changes were not observed in cells treated with estrogen and the IRE1α agonist.@*CONCLUSION@#Estrogen can inhibit the differentiation of murine macrophages into a pro-inflammatory phenotype by up-regulating the IRE1α-XBP-1 signaling axis, thereby producing an inhibitory effect on inflammatory response.

Study on the Effect Mechanism of Diazoxide on the Proliferation and Apoptosis of Chondrocytes with Oxidative Injury / 中国药房

OBJECTIVE： To investigate the effect mechanism of diazoxide on the proliferation and apoptosis of chondrocytes with oxidative injury based on endoplasmic reticulum stress （ERS） pathway. METHODS： SD mice were selected for primary culture of articular chondrocytes. The 3rd generation chondrocytes were randomly divided into control group， injury model group and diazoxide group. Control group didn’t receive any treatment. The injury model group was incubated with 300 μmol/L hydrogen peroxide （H2O2） at 37 ℃ for 8 h. Diazoxide group was pretreated with 300 μmol/L diazoxide at 37 ℃ for 0.5 h，and then incubated with 300 μmol/L H2O2 for 8 h. The proliferation of chondrocytes was detected by CCK-8 assay. The apoptosis rate of chondrocytes was detected by flow cytometry. The expression of ERS-related proteins [Caspase-3， Bcl-2-associated X（Bax），C/EBP homologous protein （CHOP）] were detected by Western blotting assay. RESULTS： Compared with control group， the proliferation activity of chondrocytes in injury model group was significantly decreased， while apoptosis rate was increased significantly（P＜0.05）；the protein expression of Caspase-3， Bax and CHOP were increased significantly （P＜0.05）. Compared with injury model group， the proliferation activity of chondrocytes in diazoxide group was increased significantly， while the apoptosis rate was decreased significantly （P＜0.05）； the expression of above related proteins were decreased significantly （P＜0.05）. CONCLUSIONS： Diazoxide can improve the proliferation activity of chondrocytes with oxidative injury and inhibit their apoptosis by inhibiting ERS pathway.

Mechanism of endoplasmic reticulum stress pathway inhibitor salubrinal enhancing the apoptosis of head and neck squamous carcinoma cells / 中华放射肿瘤学杂志

Objective To explore the mechanism underlying the effect of endoplasmic reticulum stress pathway inhibitor Salubrinal on enhancing the apoptosis of head and neck squamous carcinoma cells.Methods Three types of head and neck squamous carcinoma cell lines (KB,Fadu,Detroit562) were divided into the control,Salburinal (sal),irradiation (IR) and sal combined with IR (IR+sal) groups.The expression levels of p-ATM/ATM,DNA-PK and cleaved Caspase-3 were quantitatively measured.The cell apoptosis rate was detected among four groups.The effect of Salburinal on cell viability was evaluated by MTT assay.Results Compared with the IR group,the expression level of p-ATM/ATM (t =3.5,8.43 and 9.42,all P＜0.05) was significantly up-regulated,whereas that of DNA-PK (t =9.19,17.44,16.67,all P＜ 0.05) was considerably down-regulated in the IR+sal group.The expression level of cleaved Caspase-3 in the IR+sal group was significantly higher compared with those in the other three groups (t=6.79,9.76 and 9.7g,all P＜0.05).Compared with the IR group,the cell apoptosis rate was significantly enhanced in the IR +sal group (t=5.67,6.95 and 7.28,all P＜0.05).Salubrinal exerted an effect upon the apoptosis of three cell lines in a concentration-and time-dependent manner.Conclusions As an endoplasmic reticulum stress pathway inhibitor,Salubrinal can enhance the apoptosis rate of head and neck squamous carcinoma cells.The underlying mechanism is probably correlated with irradiation-induced DNA double strand injury,suppressing the repairing of DNA damage and thereby increasing the apoptosis of tumor cells.

Endoplasmic reticulum stress inhibitor salubrinal enhanced radiosensitivity of head and neck carcinoma cells / 中华放射医学与防护杂志

Objective To explore the effect of salubrinal (sal,an endoplasmic reticulum stress inhibitor) on radiosensitivity of human head and neck squamous carcinoma cells (HNSCC).Methods Cells were divided into two groups of sal treatment and its control.For drug treatment group,cells were treated with 10 mmol/L sal for different time (12,24,36 h) and then irradiated.The levels of a core protein GRP78 of endoplasmic reticulum stress (ERS) in HNSCC (KB,Fadu,and Detroit 562 cells)were analyzed by Western blot assay at different time (0,20 min,1 h,3 h,6 h,12 h,24 h and 48 h) after irradiation.Cell survival was measured with colony formation assay.Results Western blot assay revealed that the protein levels of GRP78 in three kinds of HNSCC significantly increased from 20 min to 1 h and peaked at 3 h after radiation (t =12.72,13.37,18.31,P ＜ 0.05).Compared with the control group,treatment of cells with sal decreased GRP78 protein levels (t =14.25,5.34,3.12,P ＜ 0.05) in three cell lines and also significantly enhanced radiation damage and reduced cell viability.The sensitization enhancement ratios (SER) of sal in three cell lines were 1.16,1.05 and 1.06,respectively.Conclusions Rradiosensitivity of HNSCC could be effectively enhanced by sal treatment.