scholarly journals Data Independent Acquisition Mass Spectrometry of the Human Lens Enhances Spatiotemporal Measurement of Fiber Cell Aging

2021 ◽  
Author(s):  
Lee S Cantrell ◽  
Kevin L Schey
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Fiber Cell ◽  
Human Lens ◽  
Cell Aging ◽  
Fiber Cells ◽  
Data Independent Acquisition ◽  
Age Related ◽  
Cell Age ◽  
Independent Analysis

The ocular lens proteome undergoes post-translational and progressive degradation as fiber cells age. The oldest fiber cells and the proteins therein are present at birth and are retained through death. Transparency of the lens is maintained in part by the high abundance crystallin family proteins (up to 300 mg/mL), which establishes a high dynamic range of protein abundance. As a result, previous Data Dependent Analysis (DDA) measurements of the lens proteome are less equipped to identify the lowest abundance proteins. In an attempt to probe more deeply into the lens proteome, we measured the insoluble lens proteome of an 18-year-old human with DDA and newer Data Independent Analysis (DIA) methods. By applying library free DIA search methods, 4,564 protein groups, 48,474 peptides and 5,577 deamidation sites were detected: significantly outperforming the quantity of identifications in using DDA and Pan-Human DIA library searches. Finally, by segmenting the lens into multiple fiber cell-age related regions, we uncovered cell-age resolved changes in proteome composition and putative function.

scholarly journals Cholesterol Bilayer Domains in the Eye Lens Health: A Review

2017 ◽  
Vol 75 (3-4) ◽  
pp. 387-398 ◽  
Author(s):  
Justyna Widomska ◽  
Witold K. Subczynski ◽  
Laxman Mainali ◽  
Marija Raguz
Keyword(s):  
Physical Properties ◽  
Age Groups ◽  
Phospholipid Composition ◽  
Cholesterol Content ◽  
Fiber Cell ◽  
Cholesterol Concentration ◽  
Human Lens ◽  
Eye Lens ◽  
Lens Fiber Cell ◽  
Age Related

Abstract The most unique biochemical characteristic of the eye lens fiber cell plasma membrane is its extremely high cholesterol content, the need for which is still unclear. It is evident, however, that the disturbance of Chol homeostasis may result in damages associated with cataracts. Electron paramagnetic resonance methods allow discrimination of two types of lipid domains in model membranes overloaded with Chol, namely, phospholipid-cholesterol domains and pure Chol bilayer domains. These domains are also detected in human lens lipid membranes prepared from the total lipids extracted from lens cortices and nuclei of donors from different age groups. Independent of the age-related changes in phospholipid composition, the physical properties of phospholipid-Chol domains remain the same for all age groups and are practically identical for cortical and nuclear membranes. The presence of Chol bilayer domains in these membranes provides a buffering capacity for cholesterol concentration in the surrounding phospholipid-Chol domains, keeping it at a constant saturating level and thus keeping the physical properties of the membrane consistent with and independent of changes in phospholipid composition. It seems that the presence of Chol bilayer domains plays an integral role in the regulation of cholesterol-dependent processes in fiber cell plasm membranes and in the maintenance of fiber cell membrane homeostasis.

The Ocular Lens Epithelium

2001 ◽  
Vol 21 (4) ◽  
pp. 537-563 ◽  
Author(s):  
Suraj P. Bhat
Keyword(s):  
Cell Mass ◽  
Single Layer ◽  
Morphological Differentiation ◽  
Lens Epithelium ◽  
Fiber Cell ◽  
Easy Access ◽  
Human Lens ◽  
Surface Epithelium ◽  
Ocular Lens ◽  
Fiber Cells

An adult lens contains two easily discernible, morphologically distinct compartments, the epithelium and the fiber-cell mass. The fiber-cell mass provides the lens with its functional phenotype, transparency. Metabolically, in comparison to the fiber cells the epithelium is the more active compartment of the ocular lens. For the purposes of this review we will only discuss the surface epithelium that covers the anterior face of the adult ocular lens. This single layer of cells, in addition to acting as a metabolic engine that sustains the physiological health of this tissue, also works as a source of stem cells, providing precursor cells, which through molecular and morphological differentiation give rise to fiber cells. Morphological simplicity, defined developmental history and easy access to the experimenter make this epithelium a choice starting material for investigations that seek to address universal questions of cell growth, development, epithelial function, cancer and aging. There are two important aspects of the lens epithelium that make it highly relevant to the modern biologist. Firstly, there are no known clinically recognizable cancers of the ocular lens. Considering that most of the known malignancies are epithelial in origin this observation is more than an academic curiosity. The lack of vasculature in the lens may explain the absence of tumors in this tissue, but this provides only a teleological basis to a very important question for which the answers must reside in the molecular make-up and physiology of the lens epithelial cells. Secondly, lens epithelium as a morphological entity in the human lens is first recognizable in the 5th–6th week of gestation. It stays in this morphological state as the anterior epithelium of the lens for the rest of the life, making it an attractive paradigm for the study of the effects of aging on epithelial function. What follows is a brief overview of the present status and lacunae in our understanding of the biology of the lens epithelium.

scholarly journals Quantitation of protein 3 content of circulating erythrocytes at the single-cell level

Blood ◽  
1985 ◽  
Vol 65 (5) ◽  
pp. 1256-1262
Author(s):  
LK Jennings ◽  
LK Brown ◽  
ME Dockter
Keyword(s):  
Light Scattering ◽  
Cell Size ◽  
Human Erythrocytes ◽  
Cell Aging ◽  
Heterogeneous Samples ◽  
Cell Age ◽  
Independent Analysis ◽  
Flow Cytofluorimetry ◽  
Scattering Signal ◽  
Membranous Material

The density and size of human erythrocytes has been roughly correlated with cell age, with the denser and smaller cells being older. Observations of this type have led to a hypothesis that the membranes of circulating erythrocytes are dynamic with respect to composition and that material is lost from the membrane during cell maturation and circulation. In this study, flow cytofluorimetry was used to investigate the distribution of the human erythrocyte anion transport protein (protein 3) in heterogeneous samples of circulating red cells. We verified that protein 3 can be specifically and quantitatively labeled in intact human erythrocytes with eosin-5-maleimide, a luminescent probe. Individual cells were accordingly analyzed for size by forward light scattering and for protein 3 content by quantitation of eosin fluorescence. Initial results indicated that the smallest erythrocytes had a protein 3 content equal to that of the largest circulating erythrocytes. This result was independently verified by light scatter-activated cell sorting; direct measurement of cell diameters by microscopy verified that the cell sizes of erythrocytes showing the 10% greatest and 10% smallest light-scattering signal were indeed distinct. Independent analysis of the size-sorted erythrocytes for protein 3 content was accomplished by gel electrophoresis of stroma from 150,000 large and small erythrocytes. Quantitative scanning densitometry of silver-stained gels of prepared stroma showed that protein 3 content of each set of fractionated cells was equal and did not vary as a function of cell size. Taken in combination with the reported correlation between increasing red blood cell age and decreasing cell size, these results indicate that any loss of membranous material during the cell aging process is not random.

scholarly journals Quantitation of protein 3 content of circulating erythrocytes at the single-cell level

Blood ◽  
1985 ◽  
Vol 65 (5) ◽  
pp. 1256-1262 ◽  
Author(s):  
LK Jennings ◽  
LK Brown ◽  
ME Dockter
Keyword(s):  
Light Scattering ◽  
Cell Size ◽  
Human Erythrocytes ◽  
Cell Aging ◽  
Heterogeneous Samples ◽  
Cell Age ◽  
Independent Analysis ◽  
Flow Cytofluorimetry ◽  
Scattering Signal ◽  
Membranous Material

Abstract The density and size of human erythrocytes has been roughly correlated with cell age, with the denser and smaller cells being older. Observations of this type have led to a hypothesis that the membranes of circulating erythrocytes are dynamic with respect to composition and that material is lost from the membrane during cell maturation and circulation. In this study, flow cytofluorimetry was used to investigate the distribution of the human erythrocyte anion transport protein (protein 3) in heterogeneous samples of circulating red cells. We verified that protein 3 can be specifically and quantitatively labeled in intact human erythrocytes with eosin-5-maleimide, a luminescent probe. Individual cells were accordingly analyzed for size by forward light scattering and for protein 3 content by quantitation of eosin fluorescence. Initial results indicated that the smallest erythrocytes had a protein 3 content equal to that of the largest circulating erythrocytes. This result was independently verified by light scatter-activated cell sorting; direct measurement of cell diameters by microscopy verified that the cell sizes of erythrocytes showing the 10% greatest and 10% smallest light-scattering signal were indeed distinct. Independent analysis of the size-sorted erythrocytes for protein 3 content was accomplished by gel electrophoresis of stroma from 150,000 large and small erythrocytes. Quantitative scanning densitometry of silver-stained gels of prepared stroma showed that protein 3 content of each set of fractionated cells was equal and did not vary as a function of cell size. Taken in combination with the reported correlation between increasing red blood cell age and decreasing cell size, these results indicate that any loss of membranous material during the cell aging process is not random.

High-dynamic-range interferometric bragg-cell spectrum analyser

1986 ◽  
Vol 133 (1) ◽  
pp. 26
Author(s):  
J. Mellis ◽  
G.R. Adams ◽  
K.D. Ward
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Spectrum Analyser ◽  
High Dynamic
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