Hydroxyapatite Nucleation and Growth on Collagen Electrospun Fibers Controlled with Different Mineralization Conditions and Phosvitin

Yilin Jie,Zhaoxia Cai,Shanshan Li,Zhuqing Xie,Meihu Ma,Xi Huang 한국고분자학회 2017 Macromolecular Research Vol.25 No.9

In a tenfold-concentrated simulated body fluid, a strategy for rapid deposition of a biomimetic calcium phosphate layer on the scaffolds of electrospun collagen nanofiber membranes was developed. The aim of this study was to explore the effects of mineralization conditions and phosvitin (PV) on hydroxyapatite nucleation and growth. The mineralization model, the pH of the environment, and the deposition time were optimized. Scanning electron microscopy (SEM) images demonstrated that homogeneous and well-crystallized inorganic mineral layers were generated in the dynamic mineralization model system after incubating 3 h at pH 5.7. PV, which possesses the highest level of phosphorylation among egg proteins, was used as a model protein to investigate the contribution of PV in the mineralization process. The morphological structure and composition of the collagen/calcium phosphate composite nanofibers were also characterized by energy dispersive spectroscopy, scanning photoelectron spectrometer, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. XRD results showed the transformation process of mineralization materials from dicalcium phosphate dihydrate (DCPD) to HA through the changes of characteristic peaks at approximately 11° of DCPD and 31.8° of HA. 1.0 mg/mL. Phosvitin significantly promoted the phase transformation from DCPD to hydroxyapatite. High performance liquid chromatography results indicated that PV induced the mineralization rather than being the part of the hydroxyapatite. The minerals formed on electrospun collagen nanofiber membranes were identified to be from hydroxyapatite. These findings extended the potential application field of PV to biomimetic material.

Improved Redundant Picture Coding Using Polyphase Downsampling for H.264

Jie Jia,김해광,최해철,김재곤,Yilin Chang 한국전자통신연구원 2007 ETRI Journal Vol.29 No.1

This paper presents an improved redundant picture coding method that efficiently enhances the error resiliency of H.264. The proposed method applies polyphase downsampling to residual blocks obtained from inter prediction and selectively encodes the rearranged residual blocks in the redundant picture coding process. Moreover, a spatial-temporal sample construction method is developed for the redundant coded picture, which further improves the reconstructed picture quality in error prone environments. Simulations based on JM11.0 were run to verify the proposed method on different test sequences in various error prone environments with average packet loss rates of 3%, 5%, 10%, and 20%. Results of the simulations show that the presented method significantly improves the robustness of H.264 to packet loss by 1.6 dB PSNR on average over the conventional redundant picture coding method.

Trapidil determines the fate of RHF rats through inhibition of ER stress

Yilin Wang,Yu Wang,Chengxi Wei,Quan Wan,Zhifei Fan,Liying Xuan,Wanru Geng,Liqun Shao,Jie Long,Junyi Gu,Ming Zhao 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.4

Pulmonary arterial hypertension is a fatal disease,especially when it causes right heart failure (RHF). However, it is difficult to treat. It has been reported thattrapidil (Tra) can improve the redox balance and cardiacconditions. In this study, we investigated the effect of Tra onRHF induced by monocrotaline (MCT) in rats. Male Wistarrats were treated with MCT or Tra. Treatment lasted 28 days,then rats were euthanized after echocardiography and catheterization. Subsequently, lungs and right ventricular myocardiawere evaluated by hematoxylin and eosin, Masson,and TUNEL staining. Protein expression was detected bywestern blotting. We found remarkably expanded rightventricle end-diastolic volume, decreased partial pressureof oxygen (PaO2), increased partial pressure of carbondioxide (PaCO2), right ventricular systolic pressure, meanpulmonary arterial pressure, lung/body weight, and liver/body weight in the RHF rat group, as well as increases inthe apoptosis rate and the expression of endoplasmic reticulumstress (ERS)-related proteins. However, these changes were significantly inhibited by Tra. Our data suggested thatinhibition of ERS is essential for improving RHF, and thattherapeutic intervention of Tra in RHF rats works by reducingERS.

Hyperoside attenuates pyrrolizidine alkaloids-induced liver injury by ameliorating TFEB-mediated mitochondrial dysfunction

Jie Xu,Aizhen Xiong,Xunjiang Wang,Xing Yan,Yilin Chen,Xuanling Ye,Zhengtao Wang,Lili Ding,Li Yang 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.8

Pyrrolizidine alkaloids (PAs) are potent hepatotoxins that can cause liver damage. Hyperoside (Hyp), a natural flavonoid, can be extracted from medicinal plants. Hyp displays hepatoprotective activity in various liver diseases. However, the potential effect and mechanism of action of Hyp in ameliorating PA-induced liver injury remain obscure. This study aimed to explore the protective effect of Hyp against PA-induced hepatotoxicity and its underlying mechanism. We established an in vitro model of PAs in mouse primary hepatocytes and developed a mouse model of acute PA toxicity to investigate the protective effect of Hyp. We found that Hyp notably attenuated PA-induced hepatotoxicity. RNA-sequencing showed that the beneficial effect of Hyp against PA-induced hepatotoxicity was associated with the transcription factor EB (TFEB)-peroxisome proliferator-activated receptor-γ coactivator-1-α (PGC1α) pathway. Our results confirmed that both the autophagy-lysosomal pathway and mitochondrial biogenesis were induced by Hyp through TFEB nuclear translocation in PA-induced liver injury. Furthermore, we demonstrated that activation of the mechanistic target of rapamycin complex 1 (mTORC1) by MHY 1485 decreased TFEB nuclear translocation and abrogated the protective effect of Hyp against PA-induced liver injury in mice. In contrast, inhibition of mTORC1 activity increased the level of TFEB and reduced hepatotoxicity induced by PAs in mouse livers. Likewise, Hyp-induced TFEB activation was validated in vitro. In conclusion, Hyp can activate the TFEB-mediated autophagy-lysosomal pathway and mitochondrial biogenesis through inhibition of mTORC1 activity, alleviating the liver injury induced by PAs, thus suggesting the potential value of Hyp in the treatment of PA-induced hepatotoxicity.

Chondrogenic Differentiation and Three Dimensional Chondrogenesis of Human Adipose-Derived Stem Cells Induced by Engineered Cartilage-Derived Conditional Media

Hengyun Sun,Yu Liu,Ting Jiang,Xia Liu,Aijuan He,Jie Li,Wenjie Zhang,Wei Liu,Yilin Cao,Guangdong Zhou 한국조직공학과 재생의학회 2014 조직공학과 재생의학 Vol.11 No.1

Due to lack of optimal inductive protocols, how to effectively improve chondrogenesis of adipose-derived stem cells (ASCs) is still a great challenge. Our previous studies demonstrated that the culture media derived from chondrocyte-scaffold constructs (conditional media) contained various soluble chondrogenic factors and were effective for directing chondrogenic differentiation of bone marrow stem cells. Nevertheless, it remains unclear whether the conditional media can induce ASCs towards chondrogenic differentiation, especially for three-dimensional (3D) cartilage formation in a preshaped scaffold. In this study, it demonstrated that the conditional media derived from chondrocyte-scaffold constructs could promote ASCs to differentiate into chondrocyte-like cells, with similar expression of type II collagen to those induced by chondrogenic growth factors. Moreover, the expression level of chondrocyte-specific genes, such as SOX9, type II collagen, and COMP, was even higher in conditional medium group (CM) than that in optimized chondrogenic growth factor group (GF), indicating that the conditional media can serve as an effective inducer for chondrogenic differentiation of ASCs. Most importantly, the conditional media could also induce ASC-scaffold constructs to form 3D cartilage-like tissue with typical lacunae structures and positive expression of cartilage specific matrices, even higher contents of GAG and type II collagen were achieved in CM group compared to GF group. The current study establishes a simple, but stable, efficient, and economical method for directing 3D cartilage formation of ASCs, a strategy that may be more closely applicable for repairing cartilage defects.