Dataset Information

Age-related cleavages of crystallins in human lens cortical fibre cells generate a plethora of low molecular weight peptides and cross-linked crystallin complexes

ABSTRACT: A large variety of low molecular weight (LMW) peptides, derived from the breakdown of crystallins, have been reported in middle to old age human lenses. The proliferation of these LMW peptides coincides with the earliest stages of cataract formation, suggesting that the protein cleavages involved may contribute to the aggregation and insolubilisation of crystallins – these being hall marks of cataractogenesis. This study reports the identification of 238 endogenous LMW crystallin peptides from the cortical extracts of human lenses aged 16, 44, 75 and 83 years. Analysis of the peptide terminal amino acids showed that Lys and Arg were situated at the C-terminus with significantly higher frequency compared to other residues, suggesting that trypsin-like proteolysis may be active in the lens cortical fibre cells. Selected reaction monitoring (SRM) analysis of a prominent αA-crystallin peptide (αA57-65) showed that the concentration of this peptide in the human lens increased gradually to middle age, after which the rate of αA57-65 formation escalated significantly. Using 2-D gel electrophoresis and nanoLC-ESI-MS/MS, 13 protein complexes of 40-150 kDa consisting of multiple crystallin components were characterised from the water soluble cortical extracts of an adult human lens. The detection of these protein complexes suggested the possibility of crystallin cross-linking, with these complexes potentially acting to stabilise degraded crystallins by sequestration into water soluble complexes.

INSTRUMENT(S): QSTAR

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Bile

DISEASE(S): Disease Free

SUBMITTER: Xiaomin Song

LAB HEAD: Xiaomin Song

PROVIDER: PXD001593 | Pride | 2016-09-29

REPOSITORIES: Pride

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Age-related cleavages of crystallins in human lens cortical fiber cells generate a plethora of endogenous peptides and high molecular weight complexes.

Su Shih-Ping SP Song Xiaomin X Xavier Dylan D Aquilina J Andrew JA

Proteins 20150819 10

Low molecular weight peptides derived from the breakdown of crystallins have been reported in adult human lenses. The proliferation of these LMW peptides coincides with the earliest stages of cataract formation, suggesting that the protein cleavages involved may contribute to the aggregation and insolubilization of crystallins. This study reports the identification of 238 endogenous LMW crystallin peptides from the cortical extracts of four human lenses representing young, middle and old-age hum ...[more]

PMID: 26238763

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Project description:The mature eye lens contains a surface layer of epithelial cells called the lens epithelium that require a functional mitochondrial population to maintain the homeostasis and transparency of the entire lens. The lens epithelium overlies a core of terminally differentiated fiber cells that must degrade their mitochondria to achieve lens transparency. These distinct mitochondrial populations make the lens a useful model system to identify those genes that regulate the balance between mitochondrial homeostasis and elimination. Here we used an RNA sequencing and bioinformatics approach to identify the transcript levels of all genes expressed by distinct regions of the lens epithelium and maturing fiber cells of the embryonic Gallus gallus (chicken) lens. Our analysis detected over 15,000 unique transcripts expressed by the embryonic chicken lens. Of these, over 3000 transcripts exhibited significant differences in expression between lens epithelial cells and fiber cells. Multiple transcripts coding for separate mitochondrial homeostatic and degradation mechanisms were identified to exhibit preferred patterns of expression in lens epithelial cells that require mitochondria relative to lens fiber cells that require mitochondrial elimination. These included differences in the expression levels of metabolic, autophagy, and mitophagy transcripts between lens epithelial cells and lens fiber cells. These data provide a comprehensive window into all genes transcribed by the lens and those mitochondrial regulatory and degradation pathways that function to maintain mitochondrial populations in the lens epithelium and to eliminate mitochondria in maturing lens fiber cells. Differentiation-state transcriptional analysis of embryonic chicken lenses was performed following microdissection of 100 embryonic day 13 (E13) chicken lenses into four distinct regions that represent a continuum of lens cell differentiation states: lens central epithelium (EC), equatorial epithelium (EQ), cortical fibers (FP), and central fibers (FC). Further analysis of the transcriptional content of biologically replicate samples was performed by Illumina directional mRNA sequencing and resulting reads mapped by TopHat and assembled with Cufflinks.

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Dataset Information

Age-related cleavages of crystallins in human lens cortical fibre cells generate a plethora of low molecular weight peptides and cross-linked crystallin complexes

Publications

Age-related cleavages of crystallins in human lens cortical fiber cells generate a plethora of endogenous peptides and high molecular weight complexes.

Similar Datasets

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