PAHSAs attenuate immune responses and promote β cell survival in autoimmune diabetic mice
Ismail Syed, … , Diane Mathis, Barbara B. Kahn
Ismail Syed, … , Diane Mathis, Barbara B. Kahn
Published September 3, 2019; First published August 5, 2019
Citation Information: J Clin Invest. 2019;129(9):3717-3731. https://doi.org/10.1172/JCI122445.
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Categories: Research Article Autoimmunity Immunology

PAHSAs attenuate immune responses and promote β cell survival in autoimmune diabetic mice

Abstract

Palmitic acid esters of hydroxy stearic acids (PAHSAs) are endogenous antidiabetic and antiinflammatory lipids. Here, we show that PAHSAs protect against type 1 diabetes (T1D) and promote β cell survival and function. Daily oral PAHSA administration to nonobese diabetic (NOD) mice delayed the onset of T1D and markedly reduced the incidence of T1D, whether PAHSAs were started before or after insulitis was established. PAHSAs reduced T and B cell infiltration and CD4+ and CD8+ T cell activation, while increasing Treg activation in pancreata of NOD mice. PAHSAs promoted β cell proliferation in both NOD mice and MIN6 cells and increased the number of β cells in NOD mice. PAHSAs attenuated cytokine-induced apoptotic and necrotic β cell death and increased β cell viability. The mechanism appears to involve a reduction of ER stress and MAPK signaling, since PAHSAs lowered ER stress in NOD mice, suppressed thapsigargin-induced PARP cleavage in human islets, and attenuated ERK1/2 and JNK1/2 activation in MIN6 cells. This appeared to be mediated in part by glucagon-like peptide 1 receptor (GLP-1R) and not the G protein–coupled receptor GPR40. PAHSAs also prevented impairment of glucose-stimulated insulin secretion and improved glucose tolerance in NOD mice. Thus, PAHSAs delayed the onset of T1D and reduced its incidence by attenuating immune responses and exerting direct protective effects on β cell survival and function.

Authors

Ismail Syed, Maria F. Rubin de Celis, James F. Mohan, Pedro M. Moraes-Vieira, Archana Vijayakumar, Andrew T. Nelson, Dionicio Siegel, Alan Saghatelian, Diane Mathis, Barbara B. Kahn

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Figure 4

PAHSA treatment increases islet β cell viability and attenuates cytokine-induced β cell death.

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PAHSA treatment increases islet β cell viability and attenuates cytokine...
(A) MIN6 cells were treated with either diluent or IL-1β (10 ng/mL) or cytomix (TNF-α plus IL-1β plus IFN-γ; 10 ng/mL each) for 40 hours in the presence of 5- or 9-PAHSA (5 μM each). The percentage of viable β cells was measured by MTT assay and calculated as the percentage of DMSO control (n = 24 wells/condition). #P < 0.05 versus control DMSO; †P < 0.05 versus control DMSO and IL-1β; *P < 0.05 versus the respective cytokine treatment. Data indicate the mean ± SEM. Differences between groups were assessed by ANOVA with Newman-Keuls multiple comparisons test. (B) MIN6 cells were treated with cytomix in the presence of 5- or 9-PAHSA (20 μM each) for 24 hours and stained with annexin V and PI. The effect of cytomix and PAHSAs on viability is expressed as a percentage of the total number of cells sorted (n = 6 wells/condition). *P < 0.05 versus control; #P < 0.05 versus cytomix. Data indicate the mean ± SEM. Differences between groups were assessed by ANOVA with Bonferroni’s multiple comparisons test. (C) Representative images of apoptotic cells in NOD mice treated for 15 weeks with vehicle or PAHSA starting at 4 weeks of age. Scale bars: 100 μm. Original magnification, ×256 (insets). (D) Female NOD mice were treated with vehicle or PAHSA for 15 weeks starting at 4 weeks of age, and the number of apoptotic cells was determined by TUNEL staining (n = 5–6/group). *P < 0.05 versus vehicle-treated mice. Data represent the mean ± SEM. Differences between groups were assessed by 2-tailed Student’s t test. (E) MIN6 cells were treated with either diluent or cytomix for 24 hours in the presence of 5- and 9-PAHSAs (20 μM each), exendin(9-39) (10 nM), and GW1100 (10 μM). The percentage of viable β cells was measured by MTT assay and calculated as the percentage of DMSO control (n = 8, for 12 wells/condition. #P < 0.05 versus control; *P < 0.05 versus cytomix alone and control alone; †P < 0.05 versus cytomix with PAHSA treatment. Data indicate the mean ± SEM. Differences between groups were assessed by ANOVA with Bonferroni’s multiple comparisons test.