Species-Related Differences in the Proteome of Rat and Human Pancreatic Beta Cells

Figure 4

Differences between human and rat beta cells in oxidative stress/heat shock protein expression and response: higher expression of PRDX3 in human beta cells. (a) Overview graph of proteins associated to oxygen radical scavenging and stress-induced heat shock proteins. Data represent mean ± SD geometrically normalized protein amounts in rat beta (black bars, ), rat alpha (white bars, ), and human beta cells (gray bars, ). (b) Human beta cells show a higher resistance to H₂O₂-induced cell death in vitro. Human and rat islets were exposed for 2 h to the indicated H₂O₂-concentrations and cell death was visualized by Hoechst-propidium iodide vital staining. (c) PRDX3 shows an islet-restricted pattern in human but not rat beta pancreas, as shown by immunofluorescence triple staining of human and rat pancreas for PRDX3 (red), insulin (green), and glucagon (white). (d) In rat beta cells, PRDX3 (and PRDX5) expression is restricted to beta cell subsets with higher glucose-NADH responsiveness as shown by quantitative LC-tandem MS. (Bars represent mean ± SD of experiments, after geometric normalization for 6 reference proteins).

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