BACKGROUND:Chondromodulin-Ⅰ is expressed mainly in the cartilage, but it is little expressed in mesenchymal stem cells. Combined with the previous study of our group, we concluded that chondromodulin-Ⅰmaybe play an important role in inducing mesenchymal stem cells into chondrocytes accurately.
OBJECTIVE:To construct an expression plasmid stably carrying chondromodulin-Ⅰ to up-regulate the expression of chondromodulin-Ⅰ in bone marrow mesenchymal stem cells.
METHODS:Specific primers were designed in rat cartilage for chondromodulin-Ⅰ gene, then the pcDNA3.1 (+) plasmid expression vector was digested by enzyme and directional connected gene to construct pcDNA3.1(+)/ChM-Ⅰ expression vector. Bone marrow mesenchymal stem cells were obtained from rats using the method of density gradient centrifugation combined with adherent culture. Recombinant plasmid pcDNA3.1(+)/ChM-Ⅰ was transfected into rat bone marrow mesenchymal stem cells with liposome method, and G418 selection was used for stable screen of transfected cells. Reverse transcription-PCR and western blot were used to detect chondromodulin-Ⅰ expression in celllines.
RESULTS AND CONCLUSION:The positive clones were digested by enzyme and were identified and sequenced. The results showed that the reality length and sequence of chondromodulin-Ⅰ gene were consistent with the theoretical values, and reading frame was correct. Reverse transcription-PCR and western blot results showed that the expressions of chondromodulin-ⅠmRNA and protein were markedly up-regulated in bone marrow mesenchymal stem cells. Recombinant plasmid pcDNA3.1(+)/ChM-I was successful y constructed, and transfected into rat bone marrow mesenchymal stem cells. After G418 selection, expression of chondromodulin-Ⅰ was up-regulated stably in rat bone marrow mesenchymal stem cells.

Objective To assess the left ventricular synchronization and global systolic function in patients with implanted dual-chamber (DDD) mode cardiac pacemakers by real-time three-dimensional echocardiography(RT-3DE). Methods Left ventricular systolic synchronization and global function were evaluated in 20 patients with implanted DDD mode cardiac pacemakers and 20 normal people by RT-3DE. The left ventricular end-diastolic volume (LEDV), end-systolic volume ( LESV), stroke volume (SV), left ventricular ejection fraction (LVEF), the mean value of time from the start of electrocardiographic QRS wave to the point of minimal systolic volume (Tmean) of the 17 segments and those standard deviation(T-SD),the maximal difference of time among all 17 segments(Tmax) were obtained by RT-3DE. Results Compared with control group, LESV was significantly increased,SV, LVEF were significantly decreased and T-SD,Tmax were significantly prolonged (P <0.01 ). There were no differences in LEDV and Tmean between the two groups (P>0.05). In patients group,LVEF correlated closely with T-SD (r =-0.674, P<0.05) and Tmax (r = - 0. 634, P < 0. 05). Conclusions There were left ventrieular systolic asychronization and global systolic dysfunction in patients with implanted dual-chamber (DDD) mode cardiac pacemakers,which could be assessed by RT-3DE.

Objective:To investigate the influence of circ_BACH2 on the malignant biological behavior of papillary thyroid cancer and its molecular mechanism.Methods:Cancer tissues and paracancer tissues of 51 patients with papillary thyroid carcinoma from the Fourth Central Hospital of Tianjin between 2017 and 2019 were collected. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to detect the expressions of circ_BACH2, miR-370-3p and G protein coupled receptor kinase interacting factor 1 (GIT1) mRNA in tissues and cells; flow cytometry to detect cell apoptosis and cell cycle; plate clone formation experiment to detect the number of cell clones; cell counting kit 8 (CCK-8) to detect cell proliferation; Transwell array to detect cell migration and invasion; western blot to detect protein expressions; dual luciferase report experiment to detect the targeting relationship between circ_BACH2, miR-370-3p and GIT1; the nude mouse tumor formation experiment to detect the effect of circ_BACH2 on tumors in mice.Results:Compared with adjacent tissues, the expressions of circ_BACH2 and GIT1 in papillary thyroid cancer tissues was increased, while the expression of miR-370-3p was decreased. Compared with Nthy-ori3-1 cells, the expressions of circ_BACH2 in papillary thyroid cancer cells TPC-1 and SW579 were increased, the mRNA and protein levels of GIT1 were increased, miR-370-3p expression was decreased. The expression level of GIT1 mRNA was negatively correlated with that of miR-370-3p ( r=-0.634), and the expression level of circ_BACH2 was positively correlated with that of GIT1 ( r=0.635). The expression level of circ_BACH2 was negatively correlated with that of miR-370-3p ( r=-0.394, P＜0.05). Circ_BACH2 and miR-370-3p has a binding site at the 3' UTR of GIT1. After knocking down circ_BACH2, the proportion of G 0/G 1 cells in papillary thyroid cancer cells TPC-1 and SW579 was increased, the proportion of S-phase cells was decreased and the proportion of G 2/M-phase cells did not change significantly. The cell absorbance value was lower than that in si-NC group. The number of cell clone formation was decreased (43±5 vs 100±6, 54±8 vs 100±9); the cell apoptosis rate was increased [(19.60±2.40)% vs (4.30±0.20)%, (18.10±2.10)% vs (5.10±0.23)%]; cell migration number was decreased (61±7 vs 134±15, 58±6 vs 112±11), the invasion number was also decreased (45±6 vs 113±11, 47±4 vs 92±9); the expressions of Snail and Twist1 were decreased, and the expression of E-cadherin was increased ( P＜0.000). Inhibition of miR-370-3p expression reversed the effect of circ_BACH2 knockdown on proliferation, migration, invasion and apoptosis of thyroid papillary cancer cells. Overexpression of GIT1 reversed the effects of overexpression of miR-370-3p on proliferation, migration, invasion and apoptosis of thyroid papillary cancer cells. Mice injected with TPC-1 cells stably transfected with sh-circ_BACH2 showed a reduction in tumor volume [(535±91) mm 3 vs (857±114) mm 3] after 35 days of culture; tumor weight was decreased [(0.62±0.13) mg vs (1.06±0.15) mg, P＜0.05]; the expressions of circ_BACH2 and GIT1 were decreased, and the expression of miR-370-3p was increased in nude mouse tumor tissue. Conclusion:Silencing circ_BACH2 may inhibit the proliferation, migration and invasion of papillary thyroid cancer cells in vitro, promote cell apoptosis, and inhibit tumor growth in vivo through targeted regulation of miR-370-3p/GIT1.

Objective:To investigate the influence of circ_BACH2 on the malignant biological behavior of papillary thyroid cancer and its molecular mechanism.Methods:Cancer tissues and paracancer tissues of 51 patients with papillary thyroid carcinoma from the Fourth Central Hospital of Tianjin between 2017 and 2019 were collected. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to detect the expressions of circ_BACH2, miR-370-3p and G protein coupled receptor kinase interacting factor 1 (GIT1) mRNA in tissues and cells; flow cytometry to detect cell apoptosis and cell cycle; plate clone formation experiment to detect the number of cell clones; cell counting kit 8 (CCK-8) to detect cell proliferation; Transwell array to detect cell migration and invasion; western blot to detect protein expressions; dual luciferase report experiment to detect the targeting relationship between circ_BACH2, miR-370-3p and GIT1; the nude mouse tumor formation experiment to detect the effect of circ_BACH2 on tumors in mice.Results:Compared with adjacent tissues, the expressions of circ_BACH2 and GIT1 in papillary thyroid cancer tissues was increased, while the expression of miR-370-3p was decreased. Compared with Nthy-ori3-1 cells, the expressions of circ_BACH2 in papillary thyroid cancer cells TPC-1 and SW579 were increased, the mRNA and protein levels of GIT1 were increased, miR-370-3p expression was decreased. The expression level of GIT1 mRNA was negatively correlated with that of miR-370-3p ( r=-0.634), and the expression level of circ_BACH2 was positively correlated with that of GIT1 ( r=0.635). The expression level of circ_BACH2 was negatively correlated with that of miR-370-3p ( r=-0.394, P＜0.05). Circ_BACH2 and miR-370-3p has a binding site at the 3' UTR of GIT1. After knocking down circ_BACH2, the proportion of G 0/G 1 cells in papillary thyroid cancer cells TPC-1 and SW579 was increased, the proportion of S-phase cells was decreased and the proportion of G 2/M-phase cells did not change significantly. The cell absorbance value was lower than that in si-NC group. The number of cell clone formation was decreased (43±5 vs 100±6, 54±8 vs 100±9); the cell apoptosis rate was increased [(19.60±2.40)% vs (4.30±0.20)%, (18.10±2.10)% vs (5.10±0.23)%]; cell migration number was decreased (61±7 vs 134±15, 58±6 vs 112±11), the invasion number was also decreased (45±6 vs 113±11, 47±4 vs 92±9); the expressions of Snail and Twist1 were decreased, and the expression of E-cadherin was increased ( P＜0.000). Inhibition of miR-370-3p expression reversed the effect of circ_BACH2 knockdown on proliferation, migration, invasion and apoptosis of thyroid papillary cancer cells. Overexpression of GIT1 reversed the effects of overexpression of miR-370-3p on proliferation, migration, invasion and apoptosis of thyroid papillary cancer cells. Mice injected with TPC-1 cells stably transfected with sh-circ_BACH2 showed a reduction in tumor volume [(535±91) mm 3 vs (857±114) mm 3] after 35 days of culture; tumor weight was decreased [(0.62±0.13) mg vs (1.06±0.15) mg, P＜0.05]; the expressions of circ_BACH2 and GIT1 were decreased, and the expression of miR-370-3p was increased in nude mouse tumor tissue. Conclusion:Silencing circ_BACH2 may inhibit the proliferation, migration and invasion of papillary thyroid cancer cells in vitro, promote cell apoptosis, and inhibit tumor growth in vivo through targeted regulation of miR-370-3p/GIT1.

DNA damage response (DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modifications play an important role in DDR, from signaling DNA damage to mediating DNA repair. In this report, we found that the E3 ligase ring finger protein 126 (RNF126) was recruited to UV laser micro-irradiation-induced stripes in a RNF8-dependent manner. RNF126 directly interacted with and ubiquitinated another E3 ligase, RNF168. Overexpression of wild type RNF126, but not catalytically-inactive mutant RNF126 (CC229/232AA), diminished ubiquitination of H2A histone family member X (H2AX), and subsequent bleomycin-induced focus formation of total ubiquitin FK2, TP53-binding protein 1 (53BP1), and receptor-associated protein 80 (RAP80). Interestingly, both RNF126 overexpression and RNF126 downregulation compromised homologous recombination (HR)-mediated repair of DNA double-strand breaks (DSBs). Taken together, our findings demonstrate that RNF126 negatively regulates RNF168 function in DDR and its appropriate cellular expression levels are essential for HR-mediated DSB repair.
Carrier Proteins ; metabolism ; Cell Line, Tumor ; DNA Breaks, Double-Stranded ; DNA Repair ; genetics ; DNA-Binding Proteins ; metabolism ; Genomic Instability ; HeLa Cells ; Histones ; metabolism ; Humans ; Nuclear Proteins ; metabolism ; RNA Interference ; RNA, Small Interfering ; genetics ; Signal Transduction ; Tumor Suppressor p53-Binding Protein 1 ; metabolism ; Ubiquitin ; Ubiquitin-Protein Ligases ; genetics ; metabolism ; Ubiquitination