Exendin-4 ameliorates high glucoseinduced fibrosis by inhibiting the secretion of miR-192 from injured renal tubular epithelial cells

Yijie Jia,Zongji Zheng,Meiping Guan,Qian Zhang,Yang Li,Ling Wang,Yaoming Xue 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Extracellular vesicles (EVs), which contain microRNA (miRNA), constitute a novel means of cell communication that may contribute to the inevitable expansion of renal fibrosis during diabetic kidney disease (DKD). Exendin-4 is effective for treating DKD through its action on GLP1R. However, the effect of exendin-4 on EV miRNA expression and renal cell communication during the development of DKD remains unknown. In this study, we found that EVs derived from HK-2 cells pre-treated with exendin-4 and high glucose (Ex-HG), which were taken up by normal HK-2 cells, resulted in decreased levels of FN and Col-I compared with EVs from HK-2 cells pre-treated with HG alone. Furthermore, we found that pretreatment with HG and exendin-4 may have contributed to a decrease in miR-192 in both HK-2 cells and EVs in a p53-dependent manner. Finally, we demonstrated that the amelioration of renal fibrosis by exendin-4 occurred through a miR-192-GLP1R pathway, indicating a new pathway by which exendin-4 regulates GLP1R. The results of this study suggest that exendin-4 inhibits the transfer of EV miR-192 from HG-induced renal tubular epithelial cells to normal cells, thus inhibiting GLP1R downregulation and protecting renal cells. This study reports a new mechanism by which exendin-4 exerts a protective effect against DKD.

Numerical investigation of heat transfer in a garment convective cooling system

Yijie Zhang,Jia Juhong,Ziyi Guo 한국의류학회 2022 Fashion and Textiles Vol.9 No.1

A personal microclimate management system is designed to maintain thermal comfort which allows people to overcome a harsh environment. It consists of several microfans placed in the garment side seam to provide cooling air. The computational fuid dynamics method was used to simulate the three-dimensional model and analysis the infuence of fan’s number and air gap distance. The obtained results depict that the introduced cool airfow will fnd its way along paths with fow resistance minimized and exhaust through several separated exit. The body heat fux is taken away at the same time. The convection efect is enhanced by the increase in the fans’ numbers, but the fans’ cooling efect varies a lot because of various air gap distances. When the air gap is small enough, the cooling air impact the body surface directly and causes ferce heat loss. While the air gap distance is large enough, the heat transfer along the skin surface could be enhanced by the eddy fow which is existed in the air gap between body and garment. These phenomena can maintain the body’s thermal comfort in a suitable range.

Heat Flux and Pressure Reduction Using Aerospike and Counterflowing Jet on Complex Hypersonic Flow

Jia Juhong,Zhang Yijie 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.2

A numerical study on a reduction of aerodynamic heating and pressure by an active or passive control strategy has been conducted. Three-dimensional double ellipsoid models with aerospike or opposing jet are investigated. In numerical analy�sis, three-dimensional Navier–Stokes equations are solved by a fi nite-volume method, and hybrid LES/RANS turbulence model is used. The results show that the use of aerospike or counterfl owing jet bring about an obvious decrease in pressure and heat fl ux values of the nose. However, both the pressure and heat fl ux appears an increase on body surface either for aerospike model or opposing jet model. For aerospike model, the aerospike will push the bow shock standing away from the fi rst ellipsoid and creates an elliptical shaped recirculation zone, in which the pressure and heat fl ux keep at a low level. After that, the shear layer will reattaches to the shoulder and creates the peak value of the heat fl ux and pressure. For opposing jet model, the counterfl owing jet fl ows out the nozzle and pushes the bow shock away from the nose. Meanwhile, the jet fl ow is pushed back by the freestream and reattached to the ellipsoid shoulder surface. Then, the heat fl ux and pressure peaks are created by reattachment. These separation and reattachment lead to the ups and downs of the surface pressure and heat fl ux.

Long noncoding RNA NEAT1 is involved in the protective effect of Klotho on renal tubular epithelial cells in diabetic kidney disease through the ERK1/2 signaling pathway

Yan-Lin Yang,Meng Xue,Yijie Jia,Fang Hu,Zongji Zheng,Ling Wang,Ze-Kun Si,Yaoming Xue 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Klotho, an antiaging protein, has been shown to play a protective role in renal tubular epithelial-mesenchymal transition (EMT) during the development of diabetic kidney disease (DKD). Long noncoding RNAs (lncRNAs) participate in the progression of EMT in many diseases. However, the effect of Klotho on lncRNAs during the development of DKD is still unknown. In this study, we found that Klotho overexpression in high-fat diet (HFD)- and streptozotocin (STZ)- induced DKD mice significantly inhibited the expression of lncRNA nuclear-enriched abundant transcript 1 (Neat1). We demonstrated that NEAT1 was significantly upregulated in both bovine serum albumin (BSA)-stimulated HK2 cells and mice with HFD- and STZ-induced diabetes. In addition, we observed that Klotho displays colocalization with NEAT1. Furthermore, overexpression of Klotho can inhibit the high expression of NEAT1 in BSA-stimulated HK2 cells, while silencing Klotho can further upregulate the expression of NEAT1. Silencing NEAT1 in HK2 cells resulted in inhibition of the EMT-related markers alpha smooth muscle actin (α-SMA) and vimentin (VIM) and the renal fibrosis-related markers transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF). The effect of NEAT1 on DKD was partly mediated by regulation of the ERK1/2 signaling pathway. Finally, we found that silencing NEAT1 can reverse the activation of EMT and fibrosis caused by Klotho silencing in a manner dependent on the ERK1/2 signaling pathway. These findings reveal a new regulatory pathway by which Klotho regulates ERK1/2 signaling via NEAT1 to protect against EMT and renal fibrosis, suggesting that NEAT1 is a potential therapeutic target for DKD.

The Silurian−Devonian granitoids in the East Kunlun orogenic belt, northern Qinghai-Tibetan plateau, China: origin and tectonic implications

Namkha Norbu,Yuegao Liu,Jinchao Li,Qunzi Jia,Wei Wang,Xiaobing Song,Yazhi Li,Huilei Kong,Yijie Gao,Xianzheng Guo,Xuegang Yao 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.6

The East Kunlun orogenic belt (EKOB) is located in the northeastern part of the Qinghai-Tibetan Plateau, China. Voluminous Silurian–Devonian granitoids were formed during the Proto-Tethys Ocean subduction and collision process. In this study, zircon U-Pb age dating, in-situ Hf isotope analyses, and whole rock major and trace element analyses have been carried out on granitoids from the central to eastern EKOB. The formation ages of granodiorite in the Bairiqili area, the granodiorite in the Wulonggou area are 410 ± 2 Ma and 396 ± 1 Ma, respectively, and the granodiorites show I-type features. The Wulonggou syenogranite with a formation age of 398 ± 2 Ma has a high differentiation index (D.I. = 89.59–92.43), and may belong to the high fractionated I-type granite. The Lalangmai tonalite with a formation age of 423 ± 2 Ma has high Sr (339–590 μg/g), εHf(t) (1.5–7.3), and low Y (3.45–6.33 μg/g), which are similar to modern adakites. The Lalangmai tonalite is the latest adakite record during the Proto-Tethys evolution in EKOB. Combined with previous studies, it is concluded that the granitoids from Cambrian to Devonian divided into four episodes. The first episode (515–436 Ma) mainly consists of I-type island arc granites and adakite, which are formed in a subduction environment. The second episode (436–427 Ma) is characterized by the S-type granites related to the collision. The third episode (427–420 Ma) is the transition period between the collision and the post-collision environment. In the fourth episodes (420–385 Ma), granitoids were formed in post-collision extensional environment, which is characterized by I-type and A-type granites. The upwelling of asthenosphere material is likely caused by the collapse of the orogenic belt. After 420 Ma, I-type and A-type granites formed at different depths but in the same environment.