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. 2017 Nov 27;67(2):265–277. doi: 10.2337/db17-0321

Figure 1.

Figure 1

The selective ubiquitin ligase inhibitor lenalidomide impairs β-cell function, Nrdp1 ubiquitination, and mitophagy. A: Calculated HOMA-β measured in multiple myeloma patients preinitiation (pre) and 12 weeks postinitiation (post) of chemotherapy (n = 11 control and 14 lenalidomide). B: GSIS after static incubations in 1.67 mmol/L and 16.7 mmol/L glucose performed in isolated CD1 islets pretreated with vehicle (DMSO) or 10 μmol/L lenalidomide for 24 h (hr) (n = 4/group). C: Fold oxygen consumption rates (OCR) in isolated islets pretreated with vehicle or 10 μmol/L lenalidomide for 24 h prior to dispersion to single cells for analysis as adherent monolayers on Seahorse flux analyzer (n = 10/group). D: Representative images of pancreas sections from C57BL/6 mice treated for 3 weeks in vivo with 50 mg/kg lenalidomide or vehicle alone, stained for insulin (cyan), LC3 (green), and SHDA (red). Nuclei are demarcated with DAPI (blue). Inset (lower right): Focused area of LC3/SDHA colocalized structures demarcated by yellow arrows. Scale bars = 10 µm. n = 4/group. E: Quantification of LC3/SDHA colocalization and total LC3+ puncta in islets from C57BL/6 mice treated in vivo with or without 50 mg/kg lenalidomide (n = 4/group and ∼900 β-cells and ∼25,000 total LC3/SDHA structures quantified/group). F: Representative Western blot of LC3 levels in isolated islets treated with vehicle or 10 μmol/L lenalidomide for 24 h with quantification (by densitometry) of LC3-II levels normalized to cyclophilin B. n = 4/group. G: Representative deconvolution images of Min6 β-cells (transfected with LC3-GFP and mito-DsRed plasmids) then treated with vehicle or 10 μmol/L lenalidomide for 24 h with addition of 5 µmol/L FCCP for the final 4 h. n = 4/group. H: Quantification of LC3-GFP/mito-DsRed and mito-DsRed colocalization and total LC3-GFP puncta in Min6 β-cells treated with vehicle or 10 μmol/L lenalidomide for 24 h with addition of 5 µmol/L FCCP for the final 4 h. (n = 4/group and ∼1,500 total GFP and DsRed puncta quantified per experiment.) *P < 0.05, **P < 0.01, ***P < 0.001 by nonpaired Student t test; $$P < 0.01 by paired Student t test.