BACKGROUND:Human leukocyte antigen (HLA), the major histocompatibility complex of human, plays an important function in the transplant rejection. Decreasing the expression of HLA wil prolong the survival time of transplants.
OBJECTIVE:To design smal interfering RNA (siRNA) of HLA-A2 and to detect the effect of siRNA-HLA-A2 on the expression of HLA-A2.
METHODS:Four kinds of siRNA-HLA-A2 domains were designed, and recombinant lentivirus expression vector were formed. The 293T cells, highly expressing HLA-A2, were infected in vitro. Then the knockout efficacy of four domains was detected to select the highly efficient siRNA-HLA-A2 target sequences. The human embryo lung fibroblasts were cultured in vitro and infected with the lentivirus carrying the target sequence. The infecting efficiency of LV-siRNA-HLA-A2 was observed under the fluorescence microscope and the silence function of this siRNA in human embryo lung fibroblasts was detected by western blot analysis.
RESULTS AND CONCLUSION:According to the mRNA sequence of HLA-A2 in Genbank, three siRNAs were designed and synthesized. In vitro, the over expression of HLA-A2 in 293K cells was successful y silenced. The HLA-A2 expression in human embryo lung fibroblasts was also efficiently silenced after the human embryo lung fibroblasts were infected by the highly efficient siRNA of HLA-A2. The efficacy was up to 80%.

BACKGROUND:There is an internal relationship between hyperhomocysteinemia and vascular calcification.However,the pathogenesis of hyperhomocysteinemia promoting vascular calcification is still unclear. OBJECTIVE:To investigate the role of bone morphogenetic protein-2 in hyperhomocysteinemia-induced vascular calcification. METHODS:Human carotid wax samples were divided into a calcified group(n=29)and a non-calcified group(n=13)according to the presence or absence of calcified plaque.Sixteen ApoE-/-mice were randomly divided into a control group and a hyperhomocysteinemia group,with 8 mice in each group.Bone morphogenetic protein-2 vector was used to transfect rat thoracic artery smooth muscle A7r5 cells,and gradient concentration of homocysteine(50,100,200,and 400 μmol/L)was utilized to treat A7r5 cells.Calcification was detected by alizarin red staining and hematoxylin-eosin staining.The interaction of bone morphogenetic protein 2 with Runt-related transcription factor 2 was detected by immunofluorescence,and the expressions of bone morphogenetic protein 2,Runt-related transcription factor 2,and α-smooth muscle actin were detected by immunohistochemistry and western blot assay. RESULTS AND CONCLUSION:(1)Human carotid artery tissue staining revealed that compared with the non-calcification group,inflammatory cells increased and calcification positive rate increased in the calcification group(P<0.05).Compared with the non-calcification group,the expressions of bone morphogenetic protein-2 and Runt-related transcription factor 2 were up-regulated,and the expression of α-smooth muscle actin was decreased in the calcification group(all P<0.05).(2)The staining of mouse arterial specimens exhibited that,the positive rate of calcified area in the hyperhomocysteinemia group was significantly higher than that in the control group(P<0.05);serum homocysteine level in the hyperhomocysteinemia group was significantly higher than that in the control group(P<0.05).Compared with the control group,the expressions of bone morphogenetic protein-2 and Runt-related transcription factor 2 were up-regulated,and the expression of α-smooth muscle actin was decreased in the hyperhomocysteinemia group(all P<0.05).(3)A7r5 cell culture analysis demonstrated that with the increase of homocysteine concentration gradient,the degree of calcification,the content of bone morphogenetic protein-2 and Runt-related transcription factor 2 protein in A7r5 cells increased(P<0.05),and the content of α-smooth muscle actin protein decreased(P<0.05).(4)The A7r5 cell culture analysis of overexpressed bone morphogenetic protein 2 showed that the calcification degree of the overexpressed bone morphogenetic protein 2 group was increased compared with the corresponding control group,the β-sodium glycerophosphate group,and the homocysteine group.RUNt-related transcription factor 2 expression up-regulated(P<0.05)and α-smooth muscle actin expression down-regulated(P<0.05).(5)The expression of bone morphogenetic protein 2 increased in A7r5 cells cultured with homocysteine in calcified medium,and the expression of Runt-related transcription factor 2 increased with the increase of bone morphogenetic protein 2 expression.(6)The results confirm that bone morphogenetic protein-2 is a key target gene in the regulation of smooth muscle cell phenotypic transformation resulting in vascular calcification by hyperhomocysteinemia.Targeted regulation of bone morphogenetic protein-2 reduces hyperhomocysteinemia-induced vascular calcification.

ObjectiveTo investigate the epidemiological characteristics and analyze the incidence trend of SARS-CoV-2 infection in Shanghai， China， and compare with the characteristics of the infection in Jilin Province of China during the same period in 2022 and Wuhan at the beginning of 2020. MethodsInformation of new locally-transmitted confirmed SARS-CoV-2 cases， imported confirmed COVID-19 cases， local asymptomatic SARS-CoV-2 carriers and imported asymptomatic SARS-CoV-2 carriers in Shanghai from March 1 to April 18， 2022 was collected for descriptive analysis. ResultsFrom March 1 to April 18， 2022， a total of 397 933 locally-transmitted SARS-CoV-2 cases were reported in Shanghai. Of those， 27 613 were clinically confirmed cases and 21 were severe cases. Ten deaths were related to COVID-19. The pathogen is Omicron variant BA.2 of SARS-CoV-2. The number of the infected subjects increased rapidly after March 24 and lead to a disease outbreak. Severe and deceased cases had severe comorbidity and were mostly unvaccinated with SARS-CoV-2 vaccines. Asymptomatic SARS-CoV-2 carriers accounted for 93.06%， which is significantly higher than that in Jilin Province during the same period （48.07%， P<0.001）. Daily increase in the number of clinically confirmed COVID-19 cases in Shanghai in 2022 was much lower than that in Wuhan， Hubei Province， in 2020. Number of daily newly imported confirmed COVID-19 cases and imported asymptomatic SARS-CoV-2 carriers declined during this period. ConclusionThe Omicron variant in Shanghai 2022 is highly infectious and less pathogenic. Omicron variant BA.2 replicates rapidly in asymptomatic carriers， which makes the carriers the major source of infection. Full-term vaccination of inactivated SARS-CoV-2 vaccine might decrease the pathogenicity and fatality of SARS-CoV-2 variants. SARS-CoV-2 of the Omicron BA2 strain is likely transmitted through aerosols and droplets， which poses a great challenge to the control of the COVID-19 pandemic in large cities with high population density and sophisticated public transportation.