Comparison of the dietary omega-3 fatty acids impact on murine psoriasis-like skin inflammation and associated lipid dysfunction

Persistent skin inflammation and impaired resolution are the main contributors to psoriasis and associated cardiometabolic complications. Omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known to exert beneficial effects on inflammatory response and lipid function. However, a specific role of omega-3 PUFAs in psoriasis and accompanied pathologies are still a matter of debate. Here, we carried out a direct comparison between EPA and DHA 12 weeks diet intervention treatment of psoriasis-like skin inflammation in the K14-Rac1V12 mouse model. By utilizing sensitive techniques, we targeted EPA- and DHA-derived specialized pro-resolving lipid mediators and identified tightly connected signaling pathways by RNA sequencing. Treatment with experimental diets significantly decreased circulating pro-inflammatory cytokines and bioactive lipid mediators, altered psoriasis macrophage phenotypes and genes of lipid oxidation. The superficial role of these changes was related to DHA treatment and included increased levels of resolvin D5, protectin DX and maresin 2 in the skin. EPA treated mice had less pronounced effects but demonstrated a decreased skin accumulation of prostaglandin E₂ and thromboxane B₂. These results indicate that modulating psoriasis skin inflammation with the omega-3 PUFAs may have clinical significance and DHA treatment might be considered over EPA in this specific disease.

Association of S100A8/A9 with lipid-rich necrotic core and treatment with biologic therapy in patients with psoriasis: results from an observational cohort study

Psoriasis is a systemic inflammatory disease with increased risk of atherosclerotic events and premature cardiovascular disease. S100A7, A8/A9, and A12 are protein complexes that are produced by activated neutrophils, monocytes, and keratinocytes in psoriasis. Lipid-rich necrotic core (LRNC) is a high-risk coronary plaque feature previously found to be associated with cardiovascular risk factors and psoriasis severity. LRNC can decrease with biologic therapy, but how this occurs remains unknown. We investigated the relationship between S100 proteins, LRNC, and biologic therapy in psoriasis. S100A8/A9 associated with LRNC in fully adjusted models (β = 0.27, P = 0.009, n=125 psoriasis patients with available coronary CT angiography scans, LRNC analyses, and serum S100A7, S100A8, S100A9, S100A12, and S100A8/A9 levels). At one year, in patients receiving biologic therapy (36 of 73 patients had 1-year CCTA scans available), a 79% reduction in S100A8/A9 levels (-172 (-291.7-26.4) vs -29.9 (-137.9- 50.5) P = 0.04) and a 0.6 mm² reduction in average LRNC area (0.04 (-0.48-0.77) vs -0.56 (-1.8- 0.13); P = 0.02) were noted. These results highlight the potential role of S100A8/A9 in the development of high-risk coronary plaque in psoriasis.

Abstract 472: Biologic Therapy Improves Lipid-rich Necrotic Core With Concomitant Reduction In S100A8/A9 In Psoriasis: Results From A Prospective, Observational Study

Introduction: S100A8/A9 is an alarmin protein complex secreted by activated neutrophils in response to inflammation and associated with atherosclerosis and cardiovascular disease. Psoriasis is a chronic inflammatory disease linked with increased levels of S100A8/A9, elevated atherosclerotic risk, and premature cardiovascular disease. Lipid-rich necrotic core (LRNC) is a high-risk coronary plaque feature predictive of future cardiovascular events with increased prevalence in psoriasis. Whether S100A8/A9 associates with LRNC is understudied. We aimed to characterize the relationship between S100A8/A9 and LRNC pre- and post-initiation of biologic therapy in psoriasis over 1 year.

Methods: Participants were part of an ongoing cohort study of 320 consecutive patients, of whom 125 had comprehensive measurement of S100 proteins by enzyme-linked immunosorbent assay and quantifiable coronary computed tomography angiography scans. LRNC was measured using Elucid Bioimaging software.

Results: S100A8/A9 positively associated with neutrophils (R=0.19, P =0.03) and inflammatory markers GlycA (R=0.30, P =0.001) and hs-CRP (R=0.24, P =0.005). Only S100A8/A9 associated with LRNC area (β=0.19, P =0.03) beyond adjustment for cardiovascular risk factors, statin use, biologic therapy, and neutrophils (β=0.22, P =0.02) ( Figure 1A ). Over 1 year, biologic therapy reduced S100A8/A9 levels by 79% (-197 (-320-21.4) vs -42.3 (-167.2-50.5); P =0.04) ( Figure 1B ) and decreased LRNC area by 0.6 mm 2 (0.04 (-0.48-0.77) vs -0.56 (-1.8-0.13); P =0.02) ( Figure 1C ).

Conclusion: Of the S100 family, the S100A8/A9 heterodimer uniquely associated with LRNC in fully adjusted models. Further, biologic therapy over 1 year reduced LRNC area concomitantly with S100A8/A9 in psoriasis. These findings underscore the impact of the S100 family in high-risk coronary plaque development and support the need for mechanistic studies to better elucidate these findings.

Wnt signaling in lung development, regeneration, and disease progression

The respiratory tract is a vital, intricate system for several important biological processes including mucociliary clearance, airway conductance, and gas exchange. The Wnt signaling pathway plays several crucial and indispensable roles across lung biology in multiple contexts. This review highlights the progress made in characterizing the role of Wnt signaling across several disciplines in lung biology, including development, homeostasis, regeneration following injury, in vitro directed differentiation efforts, and disease progression. We further note uncharted directions in the field that may illuminate important biology. The discoveries made collectively advance our understanding of Wnt signaling in lung biology and have the potential to inform therapeutic advancements for lung diseases.

Cody Aros, Carla Pantoja, and Brigitte Gomperts review the key role of Wnt signaling in all aspects of lung development, repair, and disease progression. They provide an overview of recent research findings and highlight where research is needed to further elucidate mechanisms of action, with the aim of improving disease treatments.

Distinct Spatiotemporally Dynamic Wnt-Secreting Niches Regulate Proximal Airway Regeneration and Aging

Our understanding of dynamic interactions between airway basal stem cells (ABSCs) and their signaling niches in homeostasis, injury, and aging remains elusive. Using transgenic mice and pharmacologic studies, we found that Wnt/β-catenin within ABSCs was essential for proliferation post-injury in vivo. ABSC-derived Wnt ligand production was dispensable for epithelial proliferation. Instead, the PDGFRα⁺ lineage in the intercartilaginous zone (ICZ) niche transiently secreted Wnt ligand necessary for ABSC proliferation. Strikingly, ABSC-derived Wnt ligand later drove early progenitor differentiation to ciliated cells. We discovered additional changes in aging, as glandular-like epithelial invaginations (GLEIs) derived from ABSCs emerged exclusively in the ICZ of aged mice and contributed to airway homeostasis and repair. Further, ABSC Wnt ligand secretion was necessary for GLEI formation, and constitutive activation of β-catenin in young mice induced their formation in vivo. Collectively, these data underscore multiple spatiotemporally dynamic Wnt-secreting niches that regulate functionally distinct phases of airway regeneration and aging.

High-Throughput Drug Screening Identifies a Potent Wnt Inhibitor that Promotes Airway Basal Stem Cell Homeostasis

Mechanisms underpinning airway epithelial homeostatic maintenance and ways to prevent its dysregulation remain elusive. Herein, we identify that β-catenin phosphorylated at Y489 (p-β-cateninY489) emerges during human squamous lung cancer progression. This led us to develop a model of airway basal stem cell (ABSC) hyperproliferation by driving Wnt/β-catenin signaling, resulting in a morphology that resembles premalignant lesions and loss of ciliated cell differentiation. To identify small molecules that could reverse this process, we performed a high-throughput drug screen for inhibitors of Wnt/β-catenin signaling. Our studies unveil Wnt inhibitor compound 1 (WIC1), which suppresses T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) activity, reduces ABSC proliferation, induces ciliated cell differentiation, and decreases nuclear p-β-cateninY489. Collectively, our work elucidates a dysregulated Wnt/p-β-cateninY489 axis in lung premalignancy that can be modeled in vitro and identifies a Wnt/β-catenin inhibitor that promotes airway homeostasis. WIC1 may therefore serve as a tool compound in regenerative medicine studies with implications for restoring normal airway homeostasis after injury.