NAD+ augmentation by nicotinamide riboside engages SLIT2/ROBO1 signaling to attenuate Th17 inflammation in psoriasis
Kim Han, Rachael J. Klein, Thomas C. Recupero, Anna Chiara Russo, Rahul Sharma, Anand K. Gupta, Shahin Hassanzadeh, Rebecca D. Huffstutler, Pradeep K. Dagur, Bryan Fisk, Neelam R. Redekar, Michael N. Sack
Kim Han, Rachael J. Klein, Thomas C. Recupero, Anna Chiara Russo, Rahul Sharma, Anand K. Gupta, Shahin Hassanzadeh, Rebecca D. Huffstutler, Pradeep K. Dagur, Bryan Fisk, Neelam R. Redekar, Michael N. Sack
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Clinical Research and Public Health Dermatology Immunology

NAD+ augmentation by nicotinamide riboside engages SLIT2/ROBO1 signaling to attenuate Th17 inflammation in psoriasis

Abstract

BACKGROUND Enhancing NAD+ levels with nicotinamide riboside (NR) confers antiinflammatory effects in human disease, although immunoregulatory mechanisms remain poorly characterized. We previously showed that ex vivo NR supplementation of primary CD4+ T cells from psoriatic individuals dampened immune responsiveness.METHODS To validate this in vivo, we performed a randomized, placebo-controlled NR supplementation study in individuals with mild-to-moderate psoriasis. Participants received oral NR (500 mg twice daily) or matching placebo for 4 weeks, with blood samples collected at baseline and after supplementation. NR reduced Th17 immune responsiveness.RESULTS Bulk CD4+ T cell RNA-seq identified induction of the SLIT-ROBO signaling pathway. NR supplementation increased circulating SLIT2 levels and enhanced SLIT2 production in dermal fibroblasts. Pharmacologic and genetic interrogation in CD4+ T cells and fibroblasts demonstrated that SLIT2, acting through the ROBO1 receptor, inhibited Rho GTPase signaling, thereby attenuating canonical Th17 polarization and fibroblast inflammatory activation.CONCLUSION These findings indicate that NAD+ augmentation exerts anti-inflammatory effects in psoriasis through SLIT2-ROBO1-mediated crosstalk between dermal fibroblasts and circulating CD4+ T cells, leading to suppression of Th17-driven inflammation.TRIAL REGISTRATION ClinicalTrials.gov NCT04271735 (registration date – 2020-08026), NCT01143454 (registration date - 2010-07-21), NCT01778569 (registration date – 2013-01-22), and NCT00001846 (registration date – 2001-01-11).FUNDING The NHLBI Division of Intramural Research (HL005102 – MNS).

Authors

Kim Han, Rachael J. Klein, Thomas C. Recupero, Anna Chiara Russo, Rahul Sharma, Anand K. Gupta, Shahin Hassanzadeh, Rebecca D. Huffstutler, Pradeep K. Dagur, Bryan Fisk, Neelam R. Redekar, Michael N. Sack

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Figure 3

SLIT2 mimics NR effects on Th17 immune responses.

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SLIT2 mimics NR effects on Th17 immune responses. (A) IL-17 secretion fr...
(A) IL-17 secretion from psoriatic Th0 cells treated with recombinant SLIT2 (200 ng/ml) for 72 hrs (n = 13 for healthy volunteers and n = 7 for psoriatic participants). (B) IL-17 secretion in Th17-polarized CD4+ T cells with SLIT2 (n = 14). (C) Relative mRNA expression of RORC in SLIT2-treated Th17 cells. Data were normalized to EF1a reference gene (n = 5). (D) Flow cytometry of RORC+IL-17+ from pathogenic Th17 cells treated with SLIT2 treatment (n = 12). (E and F) Immunoblot of p-STAT3, p-P70S6K, and p-S6 in Th17 cells treated with vehicle or SLIT2 (n = 7–8). The immunoblots in this figure are cropped images and the full membranes are depicted in an additional supplemental file. The data point of each participant were shown as dots and all data were represented as mean ± SEM. Analysis of multiple groups was performed by 1-way ANOVA followed by Šidák’s multiple comparisons test (A). The P values for comparisons of 2 groups were calculated using paired 2-tailed Student’s t test (Veh versus SLIT2). Veh, vehicle. *P < 0.05, **P < 0.01, ****P < 0.0001.