• Javeed, Naureen
• Brown, Matthew
• Matveyenko, Aleksey
• Her, Tracy K.

Abstract

<jats:p>Chronically elevated circulating free fatty acids (FFA) contribute to β-cell dysfunction and thus to the onset of obesity-driven type 2 diabetes (T2DM). Prolonged β-cell exposure to FFA is associated with reduced glucose-stimulated insulin secretion (GSIS), alterations in β-cell transcriptional identity, and apoptosis. However, the mechanisms that contribute to the demise of β-cells under lipotoxic conditions have yet to be fully elucidated. Increasing evidence suggests that aberrant release of extracellular vesicles (EV) contribute to the pathogenesis of β-cell failure in T2DM. However, what remains to be deciphered is the role of β-cell-derived EV in lipotoxicity-mediated β-cell failure. We set out to test the hypothesis that lipotoxicity-mediated β-cell dysfunction is mediated in part by paracrine release of ‘toxic’ β-cell-derived EV. To address this, MIN6 β-cells were exposed to palmitate (0.5 mM, 24h) and EV were isolated using differential ultracentrifugation to yield palmitate (PAL) EV (vs. control (CTL) EV). Nanoparticle Tracking Analysis (NTA) revealed a significant increase in PAL EV concentration (~1.5 fold vs. CTL EV) with a reduction in average particle size (CTL EV = 121 nm vs. PAL EV = 75 nm). β-cell functional assessment of mouse islets exposed to PAL EV (48h) resulted in significant suppression of GSIS (~3.4 fold decrease in stimulation index). Global transcriptomic analysis was assessed using RNA-Seq on islets exposed to PAL EV. Over 900 genes were differentially upregulated and ~450 genes downregulated upon PAL EV exposure (p&amp;lt;.05, FC&amp;gt;1.5). Genes upregulated with PAL EV encoded for KEGG pathways regulating protein digestion/absorption, ECM-receptor interaction, and PI3K/Akt signaling, while downregulated genes encode for pathways regulating glycolysis and protein processing in ER (FDR&amp;lt;.05). These data suggest the novel relevance of β-cell-derived EV in free fatty acid-induced β-cell failure in T2DM.</jats:p><jats:sec><jats:title>Disclosure</jats:title><jats:p>T. K. Her: None. M. Brown: None. A. Matveyenko: None. N. Javeed: None.</jats:p></jats:sec><jats:sec><jats:title>Funding</jats:title><jats:p>National Institutes of Health (R01DK098468, T32HL105355)</jats:p></jats:sec>

Topics

• nanoparticle
• impedance spectroscopy
• size-exclusion chromatography