Perilipin 2–positive mononuclear phagocytes accumulate in the diabetic retina and promote PPARγ-dependent vasodegeneration
Guillaume Blot, Rémi Karadayi, Lauriane Przegralek, Thérèse-Marie Sartoris, Hugo Charles-Messance, Sébastien Augustin, Pierre Negrier, Frédéric Blond, Frida Paulina Muñiz-Ruvalcaba, David Rivera-de la Parra, Lucile Vignaud, Aude Couturier, José-Alain Sahel, Niyazi Acar, Aida Jimenez-Corona, Cécile Delarasse, Yonathan Garfias, Florian Sennlaub, Xavier Guillonneau
Guillaume Blot, Rémi Karadayi, Lauriane Przegralek, Thérèse-Marie Sartoris, Hugo Charles-Messance, Sébastien Augustin, Pierre Negrier, Frédéric Blond, Frida Paulina Muñiz-Ruvalcaba, David Rivera-de la Parra, Lucile Vignaud, Aude Couturier, José-Alain Sahel, Niyazi Acar, Aida Jimenez-Corona, Cécile Delarasse, Yonathan Garfias, Florian Sennlaub, Xavier Guillonneau
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Research Article Inflammation Ophthalmology

Perilipin 2–positive mononuclear phagocytes accumulate in the diabetic retina and promote PPARγ-dependent vasodegeneration

Abstract

Type 2 diabetes mellitus (T2DM), characterized by hyperglycemia and dyslipidemia, leads to nonproliferative diabetic retinopathy (NPDR). NPDR is associated with blood-retina barrier disruption, plasma exudates, microvascular degeneration, elevated inflammatory cytokine levels, and monocyte (Mo) infiltration. Whether and how the diabetes-associated changes in plasma lipid and carbohydrate levels modify Mo differentiation remains unknown. Here, we show that mononuclear phagocytes (MPs) in areas of vascular leakage in DR donor retinas expressed perilipin 2 (PLIN2), a marker of intracellular lipid load. Strong upregulation of PLIN2 was also observed when healthy donor Mos were treated with plasma from patients with T2DM or with palmitate concentrations typical of those found in T2DM plasma, but not under high-glucose conditions. PLIN2 expression correlated with the expression of other key genes involved in lipid metabolism (ACADVL, PDK4) and the DR biomarkers ANGPTL4 and CXCL8. Mechanistically, we show that lipid-exposed MPs induced capillary degeneration in ex vivo explants that was inhibited by pharmaceutical inhibition of PPARγ signaling. Our study reveals a mechanism linking dyslipidemia-induced MP polarization to the increased inflammatory cytokine levels and microvascular degeneration that characterize NPDR. This study provides comprehensive insights into the glycemia-independent activation of Mos in T2DM and identifies MP PPARγ as a target for inhibition of lipid-activated MPs in DR.

Authors

Guillaume Blot, Rémi Karadayi, Lauriane Przegralek, Thérèse-Marie Sartoris, Hugo Charles-Messance, Sébastien Augustin, Pierre Negrier, Frédéric Blond, Frida Paulina Muñiz-Ruvalcaba, David Rivera-de la Parra, Lucile Vignaud, Aude Couturier, José-Alain Sahel, Niyazi Acar, Aida Jimenez-Corona, Cécile Delarasse, Yonathan Garfias, Florian Sennlaub, Xavier Guillonneau

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Figure 5

Lipid-associated MPs show vasodegenerative properties.

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Lipid-associated MPs show vasodegenerative properties. (A) Schematic rep...
(A) Schematic representation of the preparation of CtlCM and PAstimCMPAfree from healthy donor Mos treated with PA (PA-bound BSA) or BSA (unbound BSA). (B and C) HUVECs were stimulated with either CtlCM or PAstimCMPAfree. (B) Epifluorescence images of HUVEC nuclei stained with Hoescht (white). Scale bars: 100 μm. (C) Scatter plot of normalized nuclei counts. Values represent the mean ± SEM of 6 independent culture points. The P value was determined using Welch’s 2-tailed t test. (D–G) Capillary degeneration was quantified in an ex vivo assay (48). (E) Time-course of the mean ± SEM sprout number between day 4 (D4) and day 8 (D8) in the 3 treatment groups: basal medium (n = 10, black), CtlCM (n = 7, blue), and PAstimCMPAfree (n = 7, red). (F) Violin plot of the log2 FC of sprout numbers between paired day-6 and day-8 rings; dots represent individual aortic rings, and dashed lines represent the median and quartiles. P values were determined by 1-way Welch’s ANOVA test (P < 0.0001) followed by Dunnett’s T3 multiple-comparison test. (G) Aortic rings and sprouts treated with CtlCM or PAstimCMPAfree on day 6 and stained with COL4 on day 8. Left: Epifluorescence micrographs of COL4 (white). Scale bars: 500 μm. Right: Higher-magnification confocal micrographs of COL4 (green). Scale bars: 200 μm. Nuclei were stained with Hoechst (blue). (H) Schematic of the biological changes in Mos after lipid exposure and their acquired properties.