ABSTRACT
Objective:To investigate the role and mechanism of N 6-methyladenosine (m 6A) methyltransferase-like 3 (METTL3) in vascular calcification (VC) of chronic kidney disease (CKD) through apoptosis-associated protein. Methods:(1) Real-time fluorescence quantitative PCR was used to test METTL3 mRNA in serum of maintenance hemodialysis (MHD) patients. (2) Western blotting was used to detect the expression of METTL3 protein in high-phosphorus stimulated vascular smooth muscle cells (VSMCs), and immunofluorescence double lable was used to observe the distribution of METTL3 and Runt-related transcription factor 2 (Runx2). The METTL3 overexpressed and knockdown plasmids were constructed and transfected into VSMCs. Alizarin red staining was used to detect calcification degree. Western blotting was used to detect the expressions of osteogenic markers [Runx2, bone morphogenetic protein-2(BMP-2), collagen Ⅰ] and apoptosis- related proteins Bax and Bcl-2. (3) SD rats were randomly divided into control group, CKD-VC group and S-adenosylhomocysteine (SAH) intervention group. The calcification of thoracic aorta was evaluated by von Kossa staining, and the protein expressions of Runx2, Bax and Bcl-2 were detected by immunohistochemistry and Western blotting.Results:(1) METTL3 mRNA expression in MHD patients with VC was significantly lower than that in non-VC patients ( P<0.05), and was negatively correlated with coronary artery calcium score ( r=-0.65, P<0.001). (2) The expression of METTL3 in VSMCs stimulated by high phosphorus was decreased and showed a time dependence. Immunofluorescence double label showed that METTL3 and Runx2 were co-expressed in the nucleus. METTL3 was overexpressed in high-phosphorus induced VSMCs, and the expressions of Runx2, collagen I and BMP-2 were significantly decreased, accompanied by the decrease of calcified nodules and Bax/Bcl-2 ratio (all P<0.05). Conversely, METTL3 knockdown aggravated VSMCs calcification by inducing apoptosis. (3) Furthermore, METTL3 inhibitor SAH was administered in vivo, and it was found that inhibition of METTL3 expression significantly increased the calcification of rat thoracic aorta, and the Bax/Bcl-2 ratio and Runx2 expression were up-regulated. Conclusions:Serum METTL3 level is reduced in MHD patients with VC. In vivo and in vitro studies demonstrate that METTL3 inhibits VC in CKD by mediating the apoptosis-related protein Bax/Bcl-2.
ABSTRACT
Objective:To investigate the role and diagnostic value of miRNA-205 in chronic kidney disease (CKD) patients with vascular calcification.Methods:It was divided into in vitro cell experiment and retrospective cohort study. In vitro experiments were conducted by using rat thoracic aortic smooth muscle cells. Alizarin red staining and calcium content detection were used to detect the calcification of vascular smooth muscle cells (VSMCs). Alkaline phosphatase (ALP) test kit was used to measure ALP activity. Western blotting was used to detect the protein expression levels of osteogenic transcription factors runt-related transcription factor 2 (Runx2), α smooth muscle actin (α-SMA) and smooth muscle-22α (SM-22α) in VSMCs. qRT-PCR was used to detect miRNA-205 and Runx2 expression levels. The double luciferase reporter gene assay was used to verify the targeted relationship between miRNA-205 and Runx2. The non-dialysis patients with CKD 3-5 stage from June 2020 to January 2021 in the Department of Nephrology of Fourth Hospital, Hebei Medical University were selected. According to coronary artery calcium score (CACs), the patients were divided into non-calcification group (CACs=0), mild-moderate calcification group (0<CACs≤400), and severe calcification group (CACs > 400). Spearman correlation analysis was used to analyze the correlation between miRNA-205 and Runx2 and vascular calcification. Logistic regression model and receiver operating characteristic (ROC) curve analysis were used to analyze the ability of miRNA-205 to predict the vascular calcification in patients with CKD. Results:(1)Compared with the control group, calcium nodules were more, and the calcium content, ALP activity and Runx2 protein level were higher, and the expression levels of miRNA-205, α-SMA and SM-22α were significantly lower in high phosphorus group (all P<0.05). Overexpression of miRNA-205 significantly reduced the calcification of VSMCs and Runx2 protein level, and increased the protein levels of α-SMA and SM-22α (all P<0.05). miRNA-205-5p reduced the activity of luciferase in the wild-type Runx2-3'-end non-coding region plasmid. (2) Eighty CKD patients were enrolled, with age of (57.50±14.93) years old and 49 males (61.3%). The results of comparison of miRNA-205 and Runx2 expression levels in non-calcification group ( n=26), mild- moderate calcification group ( n=30) and severe calcification group ( n=24) showed that, the higher degree of calcification, the lower miRNA-205 expression level and the higher Runx2 mRNA expression level (all P<0.05). miRNA-205 was negatively correlated with CACs ( r=-0.50, P<0.01) and Runx2 was positively correlated with CACs ( r=0.55, P<0.01). Multivariate logistic regression analysis results suggested that miRNA-205 ( OR=0.451, 95% CI 0.122-0.873) was an independent influencing factor of vascular calcification in CKD patients. The area under the ROC curve of miRNA-205 and miRNA-205 combined with Runx2 for predicting vascular calcification were 0.796 (95% CI 0.697-0.859) and 0.924 (95% CI 0.866-0.982), respectively. Conclusions:miRNA-205 inhibits vascular calcification by targeting Runx2 to negatively regulate osteogenetic phenotype transformation of VSMCs and is expected to be an early diagnostic marker of vascular calcification in CKD patients.
ABSTRACT
Obej ctive To inev stigate the situation of hands only cardiopulmonary resuscitation ( CPR) and training effectiveness of CPR in middle school students.Methods By the principle of random stratified cluster sampling,7 687 middle school students in Changsha city were trained on hands only CPR through the scene theoyr teaching and anthropom orphic dummy in this study.The training content icn lued d who was rescued by CPR, whne pait ne ts require CPR,h ow logn cna causei rreversible brain damage, the stna dardized process fo CPR,the position of CP R,the depth of CPR,and the ratios of breath-to-compression. We analyzed the middle school students′awareness of hands only CPR know ledge before and after the train-ing,investigated the middle school studne ts′willign ness and way to accept knowledge of first aid.Re sulst All of 7 687 middle scoh ol students inC hangsha cti y received questionnaire us rvey and trained on hands only CPR,including 3 778(49.15%) boys and 3 909 girls(50.48%).The knowledge of hands only CPR was mainly derived from the book,television,network,and education from schools.Before training,the awareness rates of the knowledge on who was rescued by CPR and the position of CPR were more than 50%,and the awareness rates on the rest of know ledge were less than 50%.The awareness rates on hands only CPR were more than 75% by training, which were significantly increased compared with tho se before training ( P <0.01).Conclusion The knowledge on hands only CPR is very scarce in middle school students in Changsha city,and the awareness on hands only CPR can be significantly improved by the scene theory teaching and an-thropomorphic dummy.