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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19), it binds to angiotensin-converting enzyme 2 (ACE2) to enter into human cells. The expression level of ACE2 potentially determine the susceptibility and severity of COVID-19, it is thus of importance to understand the regulatory mechanism of ACE2 expression. Tripartite motif containing 28 (TRIM28) is known to be involved in multiple processes including antiviral restriction, endogenous retrovirus latency and immune response, it is recently reported to be co-expressed with SARS-CoV-2 receptor in type II pneumocytes; however, the roles of TRIM28 in ACE2 expression and SARS-CoV-2 cell entry remain unclear. This study showed that knockdown of TRIM28 induces ACE2 expression and increases pseudotyped SARS-CoV-2 cell entry of A549 cells and primary pulmonary alveolar epithelial cells (PAEpiCs). In a co-culture model of NK cells and lung epithelial cells, our results demonstrated that NK cells inhibit TRIM28 and promote ACE2 expression in lung epithelial cells, which was partially reversed by depletion of interleukin-2 and blocking of granzyme B in the co-culture medium. Furthermore, TRIM28 knockdown enhanced interferon-{gamma} (IFN-{gamma})-induced ACE2 expression through a mechanism involving upregulating IFN-{gamma} receptor 2 (IFNGR2) in both A549 and PAEpiCs. Importantly, the upregulated ACE2 induced by TRIM28 knockdown and co-culture of NK cells was partially reversed by dexamethasone in A549 cells but not PAEpiCs. Our study identified TRIM28 as a novel regulator of ACE2 expression and SARS-CoV-2 cell entry.
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Objective: To investigate the effects of overexpression of activated leukocyte cell adhesion molecule (ALCAM) gene on the biological characteristics including proliferation, apoptosis, migration and invasion of human hepatocellular carcinoma cell line HepG2. Methods: The recombinant adenovirus Ad-ALCAM carrying ALCAM gene and the empty vector Ad-null (as the control group) were infected into human hepatocellular carcinoma HepG2 cells, then the expression level of ALCAM protein in HepG2 cells was detected by Western blotting. The proliferation viability and apoptotic rate were detected by CCK-8 and FCM, respectively. The invasion and migration abilities of HepG2 cells were detected by Transwell chamber assay. The mouse xenograft model of HepG2 cells was established, and the recombinant adenovirus Ad-ALCAM-siRNA and Ad-ALCAM were locally injected into tumor tissues, respectively. Then the effects of ALCAM gene silencing and overexpression on the growth of tumor in mice were observed, and the expression of ALCAM protein and the microvessel density (MVD) (CD34 as the antigen marker) were measured by immunohistochemistry. Results: Compared with the two control groups, the expression level of ALCAM protein in HepG2 cells infected with Ad-ALCAM was significantly increased (both P < 0.01), the cell viability was increased (P < 0.05), but the apoptotic rate as well as the abilities of migration and invasion were decreased (all P < 0.05). In the mouse xenograft model injected with Ad-ALCAM, the growth of tumor was fasten, while the expression of ALCAM protein and MVD in tumor tissues were increased (all P < 0.05). In the mouse xenograft model injected with Ad-ALCAM-siRNA, the growth of tumor was declined, while the expression of ALCAM protein and MVD in tumor tissues were decreased (all P < 0.05). Conclusion: ALCAM can regulate the proliferation and invasion of hepatocellular carcinoma cells, and may be a potential marker for the diagnosis of liver cancer and the evaluation of prognosis, as well as a potential biological target for the treatment of liver cancer.
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Objective To analyze the indoor radon level and distribution characteristic in different geological background by studying the indoor radon level in three typical areas in Zhuhai City.Methods The region of investigation includes three districts:granite area in Zhuhai District,granite area in Doumen District and the Quaternary sedimentary area in Doumen District.Activated charcoal adsorption method was used to measure the indoor radon concentrations.In some sampling sites,solid state nuclear track detectors were used at the same time for the indoor radon measurement.Results The average indoor radon level included 80 buildings was (66.0 ± 49.8) Bq/m3 using activated charcoal adsorption method and the maximum value was 1078.5 Bq/m3.The results of 23 sampling sites show that the average indoor radon level using solid state nuclear track detectors was (88.8 ± 49.1) Bq/m3,and (69.5 ± 37.7) Bq/m3 by activated charcoal adsorption method.The indoor radon concentration was (73.6 ± 61.0),(87.5 ± 58.3) and (48.6 ± 22.6) Bq/m3 in granite area in Zhuhai District,granite area in Doumen District and the Quaternary sedimentary area in Doumen District,respectively.Conclusions The surface lithology of an area has a certain impact on the indoor radon level.The indoor radon level in granite area in Zhuhai District and Doumen District is apparently higher than that in the Quaternary sedimentary area in Doumen District.The study of indoor radon level and distribution characteristic should be discussed in combination with geological background of area.
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The article expounds the significance of teaching foreign medical students in English to the internationalization of the higher learning in China,and discusses the problems and challenges that will be met in the teaching practice as well as the way to solve the problems
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To improve the training quality of medical students,the questionnaire investigation was carried out to evaluate the effects of early clinic education course,which has provided us with the evidence to amend the teaching contents,teaching model,teaching methods.
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MicroRNAs (miRNAs) are endogenous non-coding RNAs discovered in recent years that post-transcriptionally regulate the gene expression. They are implicated in various biological processes including development,oncogenesis,viral and immunological diseases. Many miRNAs are highly expressed in the cardiovascular system and play an important role in cardiovascular health and diseases. In this paper,we briefly review the recent understanding of miRNAs and their role in cardiovascular pathophysiology.
