Rensselaer Polytechnic Institute

About: Rensselaer Polytechnic Institute is a education organization based out in Troy, New York, United States. It is known for research contribution in the topics: Terahertz radiation & Finite element method. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.

Micromotion of mammalian cells measured electrically.

Abstract: Motility is a fundamental property of mammalian cells that normally is observed in tissue culture by time lapse microscopy where resolution is limited by the wavelength of light. This paper examines a powerful electrical technique by which cell motion is quantitatively measured at the nanometer level. In this method, the cells are cultured on small evaporated gold electrodes carrying weak ac currents. A large change in the measured electrical impedance of the electrodes is observed when cells attach and spread on these electrodes. When the impedance is tracked as a function of time, fluctuations are observed that are a direct measure of cell motion. Surprisingly, these fluctuations continue even when the cell layer becomes confluent. By comparing the measured impedance with a theoretical model, it is clear that under these circumstances the average motions of the cell layer of 1 nm can be inferred from the measurements. We refer to this aspect of cell motility as micromotion.

Cyclophilin D deficiency attenuates mitochondrial and neuronal perturbation and ameliorates learning and memory in Alzheimer's disease.

Abstract: Mitochondrial dysfunction has been described in Alzheimer's disease, but how it is induced has remained unclear. Shi Du Yan and her colleagues find that a neurotoxic amyloid protein associated with the disease binds a mitochondrial protein called cyclophilin D and causes neuron death. The authors show that Alzheimer's disease model mice that lack cyclophilin D show improvements in learning and memory. Cyclophilin D (CypD, encoded by Ppif) is an integral part of the mitochondrial permeability transition pore, whose opening leads to cell death. Here we show that interaction of CypD with mitochondrial amyloid-β protein (Aβ) potentiates mitochondrial, neuronal and synaptic stress. The CypD-deficient cortical mitochondria are resistant to Aβ- and Ca2+-induced mitochondrial swelling and permeability transition. Additionally, they have an increased calcium buffering capacity and generate fewer mitochondrial reactive oxygen species. Furthermore, the absence of CypD protects neurons from Aβ- and oxidative stress–induced cell death. Notably, CypD deficiency substantially improves learning and memory and synaptic function in an Alzheimer's disease mouse model and alleviates Aβ-mediated reduction of long-term potentiation. Thus, the CypD-mediated mitochondrial permeability transition pore is directly linked to the cellular and synaptic perturbations observed in the pathogenesis of Alzheimer's disease. Blockade of CypD may be a therapeutic strategy in Alzheimer's disease.