Characterization of intestinal immune responses in generalized human and murine lipodystrophy
Marilena Letizia, Toka Omar, Patrick Weidner, Manuel O. Jakob, Inka Freise, Susanne M. Krug, Britt-Sabina Löscher, Elisa Rosati, Benedikt Obermayer, Reyes Gamez-Belmonte, Julia Hecker, Jörn-Felix Ziegler, Benjamin Weixler, Patrick Asbach, Desiree Kunkel, Michael Stumvoll, Konstanze Miehle, Christoph Becker, Christoph S.N. Klose, Rainer Glauben, Dieter Beule, Anja A. Kühl, Thomas Conrad, Frank Tacke, Stefan Wirtz, Andre Franke, Ashley D. Sanders, Britta Siegmund, Carl Weidinger
Marilena Letizia, Toka Omar, Patrick Weidner, Manuel O. Jakob, Inka Freise, Susanne M. Krug, Britt-Sabina Löscher, Elisa Rosati, Benedikt Obermayer, Reyes Gamez-Belmonte, Julia Hecker, Jörn-Felix Ziegler, Benjamin Weixler, Patrick Asbach, Desiree Kunkel, Michael Stumvoll, Konstanze Miehle, Christoph Becker, Christoph S.N. Klose, Rainer Glauben, Dieter Beule, Anja A. Kühl, Thomas Conrad, Frank Tacke, Stefan Wirtz, Andre Franke, Ashley D. Sanders, Britta Siegmund, Carl Weidinger
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Research Article Autoimmunity Endocrinology Gastroenterology

Characterization of intestinal immune responses in generalized human and murine lipodystrophy

Abstract

Acquired generalized lipodystrophy (AGL) is a rare metabolic disorder frequently associated with autoimmunity. Its etiology is incompletely understood, and the effect of adipose tissue loss on intestinal inflammation in AGL remains unclear. Using mass cytometry and single-cell RNA-seq, we observed an oligoclonal expansion of T cells in the periphery and inflamed intestine in a patient with AGL and Crohn’s disease (AGLCD). To explore if loss of adipose tissue triggers lymphoproliferation, we studied lipodystrophic mice as a model for AGL. Unexpectedly, lipodystrophic mice did not show T cell expansion, were protected from colitis, and displayed a defect in the development of proinflammatory T cells, which could be reversed by allogeneic fat transplantations, indicating that clonal T cell expansion in AGLCD is not primarily caused by lipodystrophy. Instead, gene sequencing revealed a T cell–intrinsic de novo neuroblastoma RAS viral oncogene homolog (NRAS) mutation, implicating somatic mosaicism as a facilitator of clonal T cell expansion and intestinal inflammation in AGLCD.

Authors

Marilena Letizia, Toka Omar, Patrick Weidner, Manuel O. Jakob, Inka Freise, Susanne M. Krug, Britt-Sabina Löscher, Elisa Rosati, Benedikt Obermayer, Reyes Gamez-Belmonte, Julia Hecker, Jörn-Felix Ziegler, Benjamin Weixler, Patrick Asbach, Desiree Kunkel, Michael Stumvoll, Konstanze Miehle, Christoph Becker, Christoph S.N. Klose, Rainer Glauben, Dieter Beule, Anja A. Kühl, Thomas Conrad, Frank Tacke, Stefan Wirtz, Andre Franke, Ashley D. Sanders, Britta Siegmund, Carl Weidinger

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Figure 5

Lipodystrophic mice are protected from DSS-induced colitis.

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Lipodystrophic mice are protected from DSS-induced colitis. (A) Experime...
(A) Experimental groups for chronic DSS colitis induction and percentage of weight loss. Differences were calculated by 1-way ANOVA with Šídák’s correction. Lines indicate mean values. (B) Histologic colitis score with representative H&E staining of distal colon sections (WT + H2O: n = 10; WT + DSS: n = 12; Lipo + H2O: n = 10; Lipo + DSS: n = 9). Differences were tested by Kruskal-Wallis with Dunn’s correction; data were pooled from 2 independent experiments. Relative cell numbers (per cm) in colonic tissue samples from WT + H2O (n = 10), WT + DSS (n = 12), and Lipo + H2O (n = 9) mice and for CD4+ (C) and CD8+ T cells (D), as assessed by flow cytometry. Differences were calculated by Mann-Whitney U test; data were pooled from 2 experiments. (E) Volcano plot of differentially regulated genes between Ppargfl/fl Adipoq-Cre and WT mice (n = 5/group) and heatmap of downregulated inflammation-related genes in DSS-treated Ppargfl/fl Adipoq-Cre versus DSS-treated WT controls. (F) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and representative genes significantly downregulated (Padj < 0.05, log2 fold change <–1) in Lipo + DSS (n = 5) versus WT + DSS (n = 5) mice. (G) Plasma anti–E. coli LPS IgG levels (WT + H2O: n = 10; WT + DSS: n = 12; Lipo + H2O: n = 9; Lipo + DSS: n = 9). Significance was determined by 1-way ANOVA with Šídák’s correction. (H and I) Calcium influx upon thapsigargin treatment in splenic CD4+ (H) and CD8+ (I) T cells from Ppargfl/fl Adipoq-Cre mice and WT littermates (n = 7/group), as assessed by flow cytometry. Data were pooled from 2 experiments. Boxes represent 25th–75th percentiles; whiskers represent minimum and maximum; line indicates the median. SEM is shown where applicable. f/f0, MFI of Fluo-4 (f) normalized to MFI average detected during 30 s baseline measurement (f0); ΔR/ΔT, calcium influx rate. Boxes range from 25th–75th percentiles. Whisker plots show minimum (smallest) and maximum (largest) values; line in box indicates the median. Data indicate the mean ± SEM (A, H, and I). *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by 1-way ANOVA corrected for multiple comparisons with Šídák’s test (A–D and G) and Mann-Whitney U 2-tailed test (H and I).