Wnt5a is involved in the pathogenesis of cutaneous lichen planus

Increased Level of Serum Wingless-Type Mouse Mammary Tumor Virus Integration Site Family Member 5a in Patients with Cutaneous Lichen Planus

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Significant reduction in the expression of interleukins-17A, 22 and 23A, forkhead box p3 and interferon gamma delineates lichen planus pigmentosus from lichen planus

Recent studies have noticed significant role of interleukin (IL)-17, 22, 23, Foxp3, interferon-gamma (IFN-γ) and Wnt5a in oral and cutaneous lichen planus (LP). This study was undertaken to assess whether similar expression exists in lichen planus pigmentosus (LPP). We recruited 30 patients of treatment-naïve 'LPP' (in absence of cutaneous/mucosal LP elsewhere, group 1), 10 patients having active treatment-naïve cutaneous 'LP' (group 2), 10 patients having 'post-LP' hyperpigmentation (in absence of active LP and off treatment for at least past 3 months, group 3), and 10 controls. Quantitative real-time polymerase chain reaction (qRT-PCR, peripheral blood mononuclear cells [PBMCs] and skin) and immunohistochemistry (IHC, skin) was performed. mRNA expression (in PBMCs) of IL-17A, IL-22, IL-23A, IFN-γ and Foxp3 was significantly decreased in group 1 and 3 as compared to group 2 (p < 0.05). Wnt5a expression was maximal in controls; and while there was no difference between group 1 and 2; whereas expression in group 3 was significantly lesser than group 1 and 2 (p < 0.05). qRT-PCR (skin) and IHC (skin) revealed similar results; and mRNA expression and mean fluorescence intensity of IL-17A, IL-22, IL-23A/R was significantly increased in group 2 and 3 compared to group 1 (p < 0.05). Mean fluorescence intensity and mRNA expression of IFN-γ, Foxp3 and Wnt5a were significantly increased in group 2 compared to group 1 (p < 0.05); whereas the difference between group 1 and 3 was not significant. Mean fluorescence intensity and mRNA expression of IL-17A, 1L-22 and IFN-γ showed no difference between group 2 and 3; whereas that of IL-23A/R, foxp3 and wnt5a were significantly higher in group 2 than group 3 (p < 0.05). Overall, maximal expression of IL-17A, IL-22, IL-23A, IFN-γ and Foxp3 (mRNA PBMCs) was observed in LP. Minimal expression of IL-17A, IL-22, IL-23A/R, IFN-γ and Foxp3 (mRNA skin and IHC skin) was seen in LPP patients. In contrast to LP, LPP lacks the expression of IFN-γ, Foxp3 and the cytokines representing Th17 pathway, and thus seems to have a distinct pathogenesis.

Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases.

The Wnt Blows: On the Functional Role of Wnt Signaling in Mycobacterium tuberculosis Infection and Beyond

In recent years, it has become apparent that the Wnt signaling pathway, known for its essential functions in embryonic development and tissue homeostasis, exerts immunomodulatory functions during inflammation and infection. Most functional studies indicate that Wnt5a exerts pro-inflammatory functions on its cellular targets, which include various types of immune and non-immune cells. Wnt5a expression has also been linked to the pathogenesis of chronic inflammatory diseases. Activation of beta-catenin-dependent Wnt signaling, e.g., by Wnt3a, has however been shown to limit inflammation by interfering with the nuclear factor kappa-light chain-enhancer of activated B-cells (NF-kappaB) pathway. This review focuses on the regulation of Wnt5a, Wnt3a, and the recently identified Wnt6 and their functional role in bacterial infections with a primary focus on pulmonary tuberculosis, a leading infectious cause of morbidity and mortality worldwide.