Tumor necrosis factor-like weak inducer of apoptosis and its receptor fibroblast growth factor-inducible 14 are expressed in urticarial vasculitis

Unbiased Analysis of Temporal Changes in Immune Serum Markers in Acute COVID-19 Infection With Emphasis on Organ Failure, Anti-Viral Treatment, and Demographic Characteristics

Identification of novel immune biomarkers to gauge the underlying pathology and severity of COVID-19 has been difficult due to the lack of longitudinal studies. Here, we analyzed serum collected upon COVID-19 admission (t1), 48 hours (t2), and seven days later (t3) using Olink proteomics and correlated to clinical, demographics, and therapeutic data. Older age positively correlated with decorin, pleiotrophin, and TNFRS21 but inversely correlated with chemokine (both C-C and C-X-C type) ligands, monocyte attractant proteins (MCP) and TNFRS14. The burden of pre-existing conditions was positively correlated with MCP-4, CAIX, TWEAK, TNFRS12A, and PD-L2 levels. Individuals with COVID-19 demonstrated increased expression of several chemokines, most notably from the C-C and C-X-C family, as well as MCP-1 and MCP-3 early in the course of the disease. Similarly, deceased individuals had elevated MCP-1 and MCP-3 as well as Gal-9 serum levels. LAMP3, GZMB, and LAG3 at admission correlated with mortality. Only CX3CL13 and MCP-4 correlated positively with APACHE score and length of stay, while decorin, MUC-16 and TNFRSF21 with being admitted to the ICU. We also identified several organ-failure-specific immunological markers, including those for respiratory (IL-18, IL-15, Gal-9) or kidney failure (CD28, VEGF). Treatment with hydroxychloroquine, remdesivir, convalescent plasma, and steroids had a very limited effect on the serum variation of biomarkers. Our study identified several potential targets related to COVID-19 heterogeneity (MCP-1, MCP-3, MCP-4, TNFR superfamily members, and programmed death-ligand), suggesting a potential role of these molecules in the pathology of COVID-19.

Serum TWEAK: A cutoff between segmental and nonsegmental vitiligo

BACKGROUND

TWEAK/Fn14 is expressed in many tissues including the skin, playing an important role in many inflammatory, autoimmune, and neoplastic cutaneous disorders.

AIMS

To assess the serum levels of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) in vitiligo patients.

METHODS

This case-control study included 100 subjects (50 vitiligo patients and 50 control subjects) recruited from Dermatology Outpatient Clinic, Benha University. All patients were subjected to complete cutaneous examination, to evaluate the clinical type, distribution and severity of vitiligo using the Vitiligo Area Scoring Index (VASI).

RESULTS

TWEAK serum levels were significantly higher in patients than in the control subjects (644.76 ± 688.93 vs 282.75 ± 125.67, respectively). Serum levels were significantly elevated in segmental versus nonsegmental vitiligo. Receiver operating characteristic (ROC) analysis revealed that TWEAK shows 80% sensitivity and 56.67% specificity in diagnosing vitiligo and 100% sensitivity and 80.09% specificity in differentiating segmental from nonsegmental vitiligo.

CONCLUSION

TWEAK may play a role in vitiligo pathogenesis. It may be used in the differentiation between segmental and nonsegmental vitiligo and represent a promising therapeutic target in vitiligo.

Tumor Necrosis Factor (TNF) Receptor Expression Determines Keratinocyte Fate upon Stimulation with TNF-Like Weak Inducer of Apoptosis

The interaction between tumor necrosis factor- (TNF-) like weak inducer of apoptosis (TWEAK) and fibroblast growth factor-inducible 14 (Fn14) regulates the fate of keratinocytes, depending on the relative expression of TNF receptor (TNFR) 1 or TNFR2. However, the precise mechanism underlying this TWEAK-mediated regulation remains unclear. The aim of this study was to provide comprehensive insight into the roles of Fn14, TNFR1/2, and other relevant molecules in the fate of keratinocytes. Further, we sought to elucidate the structural basis for the interaction of TWEAK and Fn14 in regulating cellular outcomes. Normal keratinocytes (mainly expressing TNFR1) and TNFR2-overexpressing keratinocytes were stimulated with TWEAK. Through immunoprecipitation and Western blotting of keratinocyte lysates, we elucidated the associations between Fn14, TNFR-associated factor 2 (TRAF2), cellular inhibitor of apoptosis protein 1 (cIAP1), and TNFR1/2 molecules. Additionally, we found that TRAF2 exhibited binding to Fn14, cIAP1, and TNFR1/2. Our data suggest that TWEAK induces apoptosis in normal keratinocytes and proliferation in TNFR2-overexpressing keratinocytes in a TNF-α-independent manner; however, inhibition of TRAF2 appears to reverse this effect. Interestingly, the interaction between TWEAK and Fn14 increased TNFR1-associated death domain protein and caspase-8 expression in normal keratinocytes and promoted cytoplasmic import of cIAP1 in TNFR2-overexpressing keratinocytes. In conclusion, we found that the Fn14-TRAF2-TNFR signaling axis mediates TWEAK's regulation of the fate of keratinocytes, possibly in a manner involving the TNF-α-independent TNFR signal transduction.

Treatment of urticarial vasculitis: A systematic review

Urticarial vasculitis (UV) is a difficult-to-treat condition characterized by long-lasting urticarial rashes and histopathologic findings of leukocytoclastic vasculitis. Treatment is dictated by the severity of skin and systemic involvement and the underlying systemic disease. This is a comprehensive systematic review of the efficacy of current UV treatment options. We searched for relevant studies in 7 databases, including MEDLINE, Scopus, and Web of Science. In total, 261 eligible studies and 789 unique patients with UV were included in the systematic review. Most patients with UV are adult women with chronic (≥6 weeks) and systemic disease. UV is mostly idiopathic but can be associated with drugs, malignancy, autoimmunity, and infections. It usually resolves with their withdrawal or cure. Corticosteroids are effective for the treatment of skin symptoms in more than 80% of patients with UV. However, their long-term administration can lead to potentially serious adverse effects. The addition of immunomodulatory or immunosuppressive agents often allows corticosteroid tapering and improves the efficacy of therapy. Biologicals, including omalizumab, as well as corticosteroids, cyclophosphamide, dapsone, mycophenolate mofetil, plasmapheresis, colchicine, hydroxychloroquine, intravenous immunoglobulin, nonsteroidal anti-inflammatory drugs, and cyclosporine, can be effective for both skin and systemic symptoms in patients with UV. H₁-antihistamines, montelukast, danazol, H₂-antihistamines, pentoxifylline, doxepin, and tranexamic acid are not effective in most patients with UV. As of yet, no drugs have been approved for UV, and management recommendations are based mostly on case reports and retrospective studies. Prospective studies investigating the effects of treatment on the signs and symptoms of UV are needed.

TWEAK/Fn14 Activation Participates in Skin Inflammation

Tumor necrosis factor- (TNF-) like weak inducer of apoptosis (TWEAK) participates in multiple biological activities via binding to its sole receptor-fibroblast growth factor-inducible 14 (Fn14). The TWEAK/Fn14 signaling pathway is activated in skin inflammation and modulates the inflammatory responses of keratinocytes by activating nuclear factor-κB signals and enhancing the production of several cytokines, including interleukins, monocyte chemotactic protein-1, RANTES (regulated on activation, normal T cell expressed and secreted), and interferon gamma-induced protein 10. Mild or transient TWEAK/Fn14 activation contributes to tissular repair and regeneration while excessive or persistent TWEAK/Fn14 signals may lead to severe inflammatory infiltration and tissue damage. TWEAK also regulates cell fate of keratinocytes, involving the function of Fn14-TNF receptor-associated factor-TNF receptor axis. By recruiting inflammatory cells, promoting cytokine production, and regulating cell fate, TWEAK/Fn14 activation plays a pivotal role in the pathogenesis of various skin disorders, such as psoriasis, atopic dermatitis, cutaneous vasculitis, human papillomavirus infection and related skin tumors, and cutaneous autoimmune diseases. Therefore, the TWEAK/Fn14 pathway may be a potential target for the development of novel therapeutics for skin inflammatory diseases.

TWEAK/Fn14 Signaling Involvement in the Pathogenesis of Cutaneous Disease in the MRL/lpr Model of Spontaneous Lupus

Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK, TNFSF12) and its sole receptor Fn14, belonging to the TNF ligand and receptor superfamilies respectively, are involved in cell survival and cytokine production. The role of TWEAK/Fn14 interactions in the pathogenesis of cutaneous lupus has not been explored. TWEAK treatment of murine PAM212 keratinocytes stimulated the secretion of RANTES via Fn14 and promoted apoptosis. Parthenolide, but not wortmanin or the MAPK inhibitor PD98059, significantly decreased production of RANTES, indicating that this effect of TWEAK is mediated via NF-κB signaling. UVB irradiation significantly upregulated the expression of Fn14 on keratinocytes in vitro and in vivo and increased RANTES production. MRL/lpr Fn14 knockout (KO) lupus mice were compared with MRL/lpr Fn14 wild-type (WT) mice to evaluate for any possible differences in the severity of cutaneous lesions and the presence of infiltrating immune cells. MRL/lpr Fn14 KO mice had markedly attenuated cutaneous disease as compared with their Fn14 WT littermates, as evidenced by the well-maintained architecture of the skin and significantly decreased skin infiltration of T cells and macrophages. Our data strongly implicate TWEAK/Fn14 signaling in the pathogenesis of the cutaneous manifestations in the MRL/lpr model of spontaneous lupus and suggest a possible target for therapeutic intervention.