G protein-coupled receptor kinase 2 (GRK2) participates in the phosphorylation and desensitization of G protein-coupled receptor (GPCR), impacting various biological processes such as inflammation and cell proliferation. Dysregulated expression and activity of GRK2 have been reported in multiple cells in rheumatoid arthritis (RA). However, whether and how GRK2 regulates synovial hyperplasia and fibroblast-like synoviocytes (FLSs) proliferation is poorly understood. In this study, we investigated the regulation of GRK2 and its biological function in RA. We found that GRK2 transmembrane activity was increased in FLSs of RA patients and collagen-induced arthritis (CIA) rats. Additionally, we noted a positive correlation between high GRK2 expression on the cell membrane and serological markers associated with RA and CIA. Immunoprecipitation-mass spectrometry and pull-down analyses revealed tumor necrosis factor receptor-associated factor 2 (TRAF2) as a novel substrate of GRK2. Furthermore, surface plasmon resonance (SPR) and molecular docking assays determined that the C-terminus of GRK2 binds to the C-terminus of TRAF2 at the Gln340 residue. GRK2 knockdown and the GRK2 inhibitor CP-25 attenuated synovial hyperplasia and FLS proliferation in CIA both in vitro and in vivo by decreasing GRK2 membrane expression and activity. Mechanistically, increased GRK2 transmembrane activity contributed to the recruitment of TRAF2 on the cell membrane, promoting GRK2-TRAF2 interactions that facilitate the recruitment of the E3 ubiquitin ligase TRIM47 to TRAF2. This enhanced TRAF2 Lys63 polyubiquitylation and induced nuclear factor (NF)-κB activation, leading to synovial hyperplasia and abnormal proliferation of FLSs. Our study provides a mechanistic and preclinical rationale for further evaluation of GRK2 as a therapeutic target for RA.

Objective To construct a stable synovial cell line MH7A from rheumatoid arthritis(RA)patients using lentiviral vectors that interfere with the expression of tumor necrosis factor receptor associated factor 2(TRAF2),and to study the role of TNF-α-TRAF2 signaling in MH7A abnormal proliferation.Methods Based on the design principles of human TRAF2 gene sequence and shRNA sequence,three pairs of TRAF2 shRNA interference se-quences were designed and synthesized.The primers were annealed by PCR,and a linear vector was obtained by double enzyme digestion PLKO.1-puro.The linearized vector was connected to the annealed primers through Solu-tion I,and the connected products were introduced into receptive cells.The plates were coated,and positive colo-nies were selected for sequencing.Three different recombinant plasmids of PLKO.1-TRAF2-shRNA lentivirus were constructed,and lentivirus packaging plasmids was used to package logarithmic growth phase HEK 293T cells.Vi-rus solution was collected to infect MH7A cells.At the same time,puromycin was used to screen MH7A stable transgenic strains with low TRAF2 expression.CCK-8 method,Western blot,and qPCR were used to detect the proliferation function of MH7A induced by TNF-α and low expression of TRAF2,as well as downstream signal TRAF2,P65 protein expression and mRNA levels.Results PLKO.1-TRAF2-shRNA(1),PLKO.1-TRAF2-shR-NA(2),and PLKO.1-TRAF2-shRNA(3)lentivirus vector plasmids and control group lentivirus vector plasmids PLKO.1-puro were successfully constructed.The three TRAF2-shRNA lentivirus vector plasmids and control group lentivirus vector plasmids PLKO.1-puro were respectively introduced into the lentivirus packaging plasmid of HEK 293T to obtain virus solution.After infecting MH7A cells with the virus solution,they were treated with puromycin(2.00 μ G/mL)screening and obtaining MH7A stable transgenic plants after 2 days.Through qPCR and Western blot results,it was found that the expression of TRAF2 mRNA and protein in PLKO.1-TRAF2-shRNA(1)MH7A stably transfected cells was significantly reduced compared to the negative control group.The results of CCK-8 and Western blot showed that after knocking down TRAF2 in MH7A,the proliferation of MH7A cells with low TRAF2 expression induced by TNF-α and the phosphorylation level of P65 were significantly reduced.Conclusion A sta-ble transgenic strain of PLKO.1-TRAF2-shRNA(1)MH7A cells was successfully constructed to investigate the role of TNF-α-TRAF2 signal activation in mediating abnormal proliferation of RA synovial cells.

Objective To explore the effects of different dose rates of X-ray under the same dose on cell clonogenic formation in non-small-cell lung cancer cell line A549 in order to provide experimental basis for clinical radiotherapy plan. Methods The A549 cells were cultured at low density and irradiated with X-rays at dose of 4 Gy and selected dose rates of 1, 2, 4 and 6 Gy/min, respectively, from a linear accelerator. The 8th day after irradiation, the cells were fixed and stained with Giemsa solution, and colonies containing at least 50 cells were counted. The plating efficiency and surviving fraction were calculated. Results The clonogenic number in non-irradiated cells was 88.6±4.6. The numbers were significantly reduced in irradiated cells at dose rate 1, 2, 4 and 6 Gy/min (12.3±3.4, 9.0±0.8, 5.6±1.0, 11.5±1.7, respectively) than that in non-irradiated control cells (F=678.799, P<0.05). The plating efficiencies were decreased in irradiated cells, especially in 4 Gy/min irradiated cells, which was lower than that in any of the other three dose rate groups (P< 0.05). Conclusions Though at same radiation dose, cancer cells have different clonogenic formation efficiency when irradiation with X-ray at different dose rates. Thus, treatment with optimal dose rate may improve the radiotherapy efficacy.

Objective To study the clinical efficacy of anus-preserving rectectomy by using telescopic anastomosis of colon and rectal mucosa for the middle and lower rectal cancer. Methods A retrospective analysis was carried out in 402 cases with middle and lower rectal cancer undergoing telescopic anastomosis for anus-preserving procedure, including 241 males and 161 females, age ranging from 21 to 99 years, averaging at 55. 7 years. The distal margins of the tumors were within 6 - 9 cm to anal verge. According to TNM staging, there were 123 cases in Stage Ⅰ , 244 cases in Stage Ⅱ , 31 cases in Stage Ⅲ,and 4 cases in Stage Ⅳ. Results 345(345/402, 85. 8% ) cases were followed up, the median time of the follow-up was 6. 1 years. Postoperative complications included 17(4.2%) cases of stomal leakage, 11(2.7% ) cases of stomal stenosis. All patients recovered normal defecating function 12-24 weeks post operation. Local recurrence rate was 6. 3% (22/345). Hepatic and lung metastasis was 13. 6% (47/345) and 2. 6% (9/345)respectively. The five year survival rate was 68. 7% (112/163). Conclusions Anuspreserving rectectomy by using telescopic anastomosis is safe and effective procedure to treat middle and lower rectal cancer, with the preservation of anal function and without the increasing rate of local recurrence.

Objective To study clinical therapeutic effects of anus-preserving operation with resecting anal intersphincter to treat ultra-low rectal cancer through abdominal cavity. Methods We retrospectively analyzed 52 cases of ultra-low rectal cancer, with the inferior border of the cancers within 2 cm to anocutaneous line or 5 cm to the edge of anus treated by anus-preserving operation with resecting archos internal sphincter muscles through abdominal cavity and anus. There were 29 males, and 23 females, with age 28 to 76 years old, averaging 56. 3 years old. The inferior border of the cancer were within 4 cm to the edge of anus in 18 cases, including 6 cases of adenoma cancerization, and 5 cm to the anus in 34 cases. Pathologic diagnosis was well-differentiated adenocarcinoma in 21 cases, moderately differentiated in 29 cases, low differentiated in 2 cases, there were 6 cases with adenoma cancerization. 28 cases were Dukes A stage, and 24 B stage. Results The follow-up rate was 88. 4% (46/52), and the median time was 5.9 years. 2 case developed stoma leak (3.8%), and 3 developed stoma stenosis(5.7% ) after operation. The anus could roughly control defecation in 6 ～ 12 mouths after operation. The local recurrence rate was 5.7%, and the 5-year-survival rate was 72.7%. Conclusion By anus-preserving operation with resecting archos internal sphincter muscles, defecation controlling was well reserved by anus, and the 5-year-survival rate was not cut down. This operation is one of the safe and effective operations of anus-preserving procedure.