Dissecting the interaction between tissue inhibitor of metalloproteinases-3 (TIMP-3) and low density lipoprotein receptor-related protein-1 (LRP-1): Development of a "TRAP" to increase levels of TIMP-3 in the tissue
MATRIX BIOLOGY
Authors: Scilabra, Simone D.; Yamamoto, Kazuhiro; Pigoni, Martina; Sakamoto, Kazuma; Mueller, Stephan A.; Papadopoulou, Alkmini; Lichtenthaler, Stefan F.; Troeberg, Linda; Nagase, Hideaki; Kadomatsu, Kenji
Abstract
Tissue inhibitor of metalloproteinases 3 (TIMP-3) is a key regulator of extracellular matrix turnover for its ability to inhibit matrix metalloproteinases (MMPs), adamalysin-like metalloproteinases (ADAMs) and ADAMs with thrombospondin motifs (ADAMTSs). TIMP-3 is a secreted protein whose extracellular levels are regulated by endocytosis via the low-density-lipoprotein receptor-related protein-1 (LRP-1). In this study we developed a molecule able to "trap" TIMP-3 extracellularly, thereby increasing its tissue bioavailability. LRP-1 contains four ligand-binding clusters. In order to investigate the TIMP-3 binding site on LRP-1, we generated soluble minireceptors (sLRPs) containing the four distinct binding clusters or part of each cluster. We used an array of biochemical methods to investigate the binding of TIMP-3 to different sLRPs. We found that TIMP-3 binds to the ligand-binding cluster II of the receptor with the highest affinity and a soluble minireceptor containing the N-terminal half of cluster II specifically blocked TIMP-3 internalization, without affecting the turnover of metalloproteinases. Mass spectrometry-based secretome analysis showed that this minireceptor, named T3TRAP, selectively increased TIMP-3 levels in the extracellular space and inhibited constitutive shedding of a number of cell surface proteins. In conclusion, T3TRAP represents a biological tool that can be used to modulate TIMP-3 levels in the tissue and could be potentially developed as a therapy for diseases characterized by a deficit of TIMP-3, including arthritis. (C) 2016 Elsevier B.V. All rights reserved.
Correlations Between Single Nucleotide Polymorphisms, Cognitive Dysfunction, and Postmortem Brain Pathology in Alzheimer's Disease Among Han Chinese
NEUROSCIENCE BULLETIN
Authors: Yang, Qian; Chen, Kang; Zhang, Hanlin; Zhang, Wanying; Gong, Changlin; Zhang, Qing; Liu, Pan; Sun, Tianyi; Xu, Yuanyuan; Qian, Xiaojing; Qiu, Wenying; Ma, Chao
Abstract
In this study, the distribution of five Alzheimer's disease (AD)-related single nucleotide polymorphisms (SNPs) in the Han population was examined in combination with the evaluation of clinical cognition and brain pathological analysis. The associations among SNPs, clinical daily cognitive states, and postmortem neuropathological changes were analyzed in 110 human brains from the Chinese Academy of Medical Sciences/Peking Union Medical College (CAMS/PUMC) Human Brain Bank. APOE epsilon 4 (OR=4.482, P=0.004), the RS2305421 GG genotype (adjusted OR=4.397, P=0.015), and the RS10498633 GT genotype (adjusted OR=2.375, P=0.028) were associated with a higher score on the ABC (A plaque score, Braak NFT stage, and CERAD neuritic plaque score) dementia scale. These results advance our understanding of the pathogenesis of AD, the relationship between pathological diagnosis and clinical diagnosis, and the SNPs in the Han population for future research.