COPS5 Protein Overexpression Increases Amyloid Plaque Burden,Decreases Spinophilin-immunoreactive Puncta,and Exacerbates Learning and Memory Deficits in the Mouse Brain

Brain accumulation of neurotoxic amyloid β (Aβ) peptide because of increased processing of amyloid precursor protein (APP), resulting in loss of synapses and neurodegeneration, is central to the pathogenesis of Alzheimer disease (AD). Therefore, the identification of molecules that regulate Aβ generation and those that cause synaptic damage is crucial for future therapeutic approaches for AD. We demonstrated previously that COPS5 regulates Aβ generation in neuronal cell lines in a RanBP9-dependent manner. Consistent with the data from cell lines, even by 6 months, COPS5 overexpression in APΔE9 mice (APΔE9/COPS5-Tg) significantly increased Aβ40 levels by 32% (p < 0.01) in the cortex and by 28% (p < 0.01) in the hippocampus, whereas the increases for Aβ42 were 37% (p < 0.05) and 34% (p < 0.05), respectively. By 12 months, the increase was even more robust. Aβ40 levels increased by 63% (p < 0.001) in the cortex and by 65% (p < 0.001) in the hippocampus. Similarly, Aβ42 levels were increased by 69% (p < 0.001) in the cortex and by 71% (p < 0.011) in the hippocampus. Increased Aβ levels were translated into an increased amyloid plaque burden both in the cortex (54%, p < 0.01) and hippocampus (64%, p < 0.01). Interestingly, COPS5 overexpression increased RanBP9 levels in the brain, which, in turn, led to increased amyloidogenic processing of APP, as reflected by increased levels of sAPPβ and decreased levels of sAPPα. Furthermore, COPS5 overexpression reduced spinophilin in both the cortex (19%, p < 0.05) and the hippocampus (20%, p < 0.05), leading to significant deficits in learning and memory skills. Therefore, like RanBP9, COPS5 also plays a pivotal role in amyloid pathology in vivo.     

The Ca sensor S100A1 modulates neuroinflammation,histopathology and Akt activity in the PSAPP Alzheimer's disease mouse model

The contribution of the Ca²⁺ sensor S100A1 to in vivo Alzheimer's disease (AD) pathobiology has not been elucidated although S100A1 regulates numerous cellular processes linked to AD. This study uses genetic ablation to ascertain the effects of S100A1 on neuroinflammation, beta-amyloid (Aβ) plaque deposition and Akt activity in the PSAPP AD mouse model. PSAPP/S100A1^−/− mice exhibited decreases in astrocytosis (GFAP burden), microgliosis (Iba1 burden) and plaque load/number when compared to PSAPP/S100A1^+/+ mice at six and twelve months of age. The presence of detectable S100A1 staining in human AD specimens is consistent with a detrimental gain of S100A1 function in AD. S100A1 ablation also reduced plaque associated and increased non-plaque associated PO₄-Akt and PO₄-GSK3β staining. S100A1·Akt complexes were undetectable in PC12 cells and AD brain tissue suggesting that S100A1 indirectly modulates Akt activity. In contrast, S100A1·RyR (ryanodine receptor) complexes were present in human/mouse AD brain and exhibited Ca²⁺-dependent formation in neuronal cells. This is the first direct demonstration of an S100A1· target protein complex in tissue/cells and identifies the RyR as a primary S100A1 target protein in the brain. Collectively, these data suggest that S100A1 inhibition may be a novel strategy for normalizing aberrant Ca²⁺ signaling in AD.     

Effects of mechanical properties and atherosclerotic artery size on biomechanical plaque disruption – Mouse vs. human

Mouse models of atherosclerosis are extensively being used to study the mechanisms of atherosclerotic plaque development and the results are frequently extrapolated to humans. However, major differences have been described between murine and human atherosclerotic lesions and the determination of similarities and differences between these species has been largely addressed recently. This study takes over and extends previous studies performed by our group and related to the biomechanical characterization of both mouse and human atherosclerotic lesions. Its main objective was to determine the distribution and amplitude of mechanical stresses including peak cap stress (PCS) in aortic vessels from atherosclerotic apoE^-/- mice, in order to evaluate whether such biomechanical data would be in accordance with the previously suggested lack of plaque rupture in this model. Successful finite element analysis was performed from the zero-stress configuration of aortic arch sections and mainly indicated (1) the modest role of atherosclerotic lesions in the observed increase in residual parietal stresses in apoE^-/- mouse vessels and (2) the low amplitude of murine PCS as compared to humans. Overall, the results from the present study support the hypothesis that murine biomechanical properties and artery size confer less propensity to rupture for mouse lesions in comparison with those of humans.     

巨细胞病毒中性红斑定量试验与高滴度病毒的制备

在巨细胞病毒(CMV)的研究中常需对病毒定量。CMV需低滴度传代,否则会产生没有感染性的缺损病毒颗粒;CMV的抗原性受其感染量的影响;检测CMV中和抗体或纯化病毒都需具备病毒空斑定量基础。另外,制备高感染滴度的无细胞病毒(游离病毒)是对CMV进行分子生物学研究的前提。本文建立了CMV微量板法中性红斑定量技术并比较了几种制备无细胞CMV的方法。     

Dietary iron restriction increases plaque stability in apolipoprotein-E-deficient mice

Accumulative evidence has supported the role of iron in the development of atherosclerosis. To test whether iron-mediated oxidative stress influences plaque stability, apoliporotein-E (ApoE)-deficient mice (3 months old) were placed on a chow diet or a low-iron diet for 3 months, and the abundance of interstitial collagen and the expression of the matrix degradation-associated enzyme, matrix metalloproteinase-9 (MMP-9), in vascular lesions were assessed. A low-iron diet appeared to reduce iron deposition while substantially increasing collagen content of lesions in mice. Immunostaining demonstrated lower expression of MMP-9 in lesions of iron-restricted animals. Likewise, SDS-PAGE zymography revealed lower gelatinolytic activities in aortic tissues and sera of the same group of animals. When older ApoE-deficient mice (5 months old) received a low-iron diet for 2 months, development of the lesion area was not significantly affected. However, the lesional collagen content was much higher in the iron-restricted group of animals, and MMP-9 expression in aortic tissues from the same group of mice was significantly lower. Treatment of murine J774 macrophages with increasing concentrations of ferric ammonium citrate significantly enhanced the amount of MMP-9 secreted. Together, these data indicate that decreased vascular iron content following dietary iron restriction in ApoE-deficient mice leads to lower matrix degradation capacity and increased plaque stability.     

A phenomenological model for atherosclerotic plaque growth and rupture

The objective of this communication is to develop a computer-based framework for the overall coupled phenomena leading to growth and rupture of atherosclerotic plaques. The modeling is purposely simplified to expose the dominant phenomenological controlling mechanisms, and their coupled interaction. The main ingredients of the present simplified modeling approach, describing the events that occur due to the presence and oxidation of excess low-density lipoprotein (LDL) in the intima, are: (i) adhesion of monocytes to the endothelial surface, which is controlled by the intensity of the blood flow and the adhesion molecules stimulated by the excess LDL, (ii) penetration of the monocytes into the intima and subsequent inflammation of the tissue, and (iii) rupture of the plaque accompanied with some degree of thrombus formation or even subsequent occlusive thrombosis. The set of resulting coupled equations, each modeling entirely different physical events, is solved using an iterative staggering scheme, which allows the equations to be solved in a computationally convenient decoupled fashion. Theoretical convergence properties of the scheme are given as a function of physical parameters involved. A numerical example is given to illustrate the modeling approach and an a priori prediction for time to rupture as a function of arterial geometry, diameter of the monocyte, adhesion stress, bulk modulus of the ruptured wall material, blood viscosity, flow rate and mass density of the monocytes.     

口泰含漱液对控制菌斑和牙龈炎的疗效分析

本研究采用双盲随机对照法观察口泰含液对牙龈炎及控制菌斑的疗效。结果显示：实验组的牙龈指数,龈沟出血指数及菌斑指数以在含漱５天后均有明显的改善,且与对照组的比较也有明显的差异。