ACR Meeting Abstracts

ACR Meeting Abstracts

Abstract Number: 1816

Paracrine WNT Signaling Drives Pro-fibrotic Metabolic Activation of Systemic Sclerosis Macrophages

Emily Morris1, Helen Jarnagin2, Heetaek Yang3, Alexandra Turnquist2, Michael Whitfield4 and Patricia Pioli5, 1Dartmouth College, Enfield, NH, 2Dartmouth College, Lebanon, NH, 3Dartmouth College, West Lebanon, NH, 4Geisel School of Medicine at Dartmouth, Hanover, NH, 5Geisel School of Medicine at Dartmouth, Lebanon, NH

Meeting: ACR Convergence 2024

Keywords: , , ,

Session Information

Date: Monday, November 18, 2024

Title: Systemic Sclerosis & Related Disorders – Basic Science Poster II

Session Type: Poster Session C

Session Time: 10:30AM-12:30PM

Background/Purpose: While we have shown that systemic sclerosis (SSc) dermal fibroblasts and macrophages (MØs) engage in reciprocal activation mediated by exosomes via paracrine signaling, the molecular mechanism underlying this mutual activation is unknown. Because MØ metabolic activity has recently emerged as a critical factor in the regulation of fibrotic disease, we hypothesized that SSc fibroblast-derived exosomes may modulate pro-fibrotic activation of MØs through metabolic reprogramming.

Methods: Primary human monocyte-derived MØs (hMDMs) were activated with SSc or control fibroblast-derived exosomes and metabolically phenotyped. The ability of SSc exosomes to activate MØs after treatment with metabolic inhibitors was assessed by flow cytometry, ELISA, and qRT-PCR. Exosome protein content was interrogated to identify candidate regulators of metabolic activity. 

Results: SSc fibroblast-derived exosomes increased the basal metabolic rate of hMDMs, upregulated mitochondrial dependency, decreased glycolytic capacity, and increased lipid uptake relative to healthy controls. OXPHOS blockade abrogated the ability of SSc fibroblast exosomes to induce pro-fibrotic activation of hMDMs, and prevented reciprocal activation of SSc fibroblasts by SSc exosome-activated hMDMs in co-culture. SSc fibroblast exosomes upregulated expression of WNT5A, and pretreatment with Wnt pathway inhibitors abrogated SSc exosome-mediated activation. Treatment of hMDMs with rWNT5A partially recapitulated the MØ activation profile conferred by SSc fibroblast exosomes via a pSTAT3-dependent mechanism.

Conclusion: Here we provide evidence for the emerging role of immunometabolic dysfunction in SSc. Our data suggest that paracrine WNT-signaling induces metabolic shift in MØs in SSc that are mediate pro-fibrotic activation. These results provide foundational support for further investigation of the therapeutic utility of targeting MØ metabolism and noncanonical WNT-signaling for the treatment of SSc.

Supporting image 1

Exosomal WNT5A induces pro-fibrotic activation of macrophages by modulating mitochondrial metabolism and pSTAT3 activation in SSc. (A) SCENITH (single-cell energetic metabolism by profiling translation inhibition) MFI data for macrophage puromycin incorporation after activation with healthy control (HC) or SSc fibroblast-derived exosomes showing increased basal metabolism in SSc exosome-stimulated macrophages. (B) Representative blot for WNT5A in SSc and HC fibroblast-derived exosomes. (C-D) SCENITH MFI data for macrophage puromycin incorporation and calculated metabolic profiles after activation with HC exosomes, SSc exosomes, or SSc exosomes pretreated with the WNT5A receptor (FZD5) inhibitor, BOX5, demonstrating efficient blockade of SSc-exosome effects upon BOX5 treatment. (E) SCENITH MFI data for puromycin incorporation in unstimulated or recombinant WNT5A-treated macrophages showing partial recapitulation of SSc exo metabolic profile. (F) pSTAT3 MFI data in unstimulated and rWNT5A-treated macrophages. (G) Supernatant CCL2 & TNFa ELISAs for unstimulated macrophages, rWNT5A-treated macrophages, and rWNT5A-treated macrophages pre-treated with the pSTAT3 inhibitor, Stattic, demonstrating the SSc exosome-like phenotype induced by WNT5A is pSTAT3-dependent.

Disclosures: E. Morris: None; H. Jarnagin: None; H. Yang: None; A. Turnquist: None; M. Whitfield: Abbvie, 6, Boehringer Ingelheim, 1, 2, Bristol-Myers Squibb, 2, 5, Celdara Medical, LLC, 5, 8, 9, 10, UCB Biopharma, 2, 5; P. Pioli: Celdara Medical, 5.

To cite this abstract in AMA style:

Morris E, Jarnagin H, Yang H, Turnquist A, Whitfield M, Pioli P. Paracrine WNT Signaling Drives Pro-fibrotic Metabolic Activation of Systemic Sclerosis Macrophages [abstract]. Arthritis Rheumatol. 2024; 76 (suppl 9). https://acrabstracts.org/abstract/paracrine-wnt-signaling-drives-pro-fibrotic-metabolic-activation-of-systemic-sclerosis-macrophages/. Accessed .

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/paracrine-wnt-signaling-drives-pro-fibrotic-metabolic-activation-of-systemic-sclerosis-macrophages/