Analysis of CARD14 Polymorphisms in Pityriasis Rubra Pilaris: Activation of NF-κB.

Pityriasis rubra pilaris (PRP) is a rare inflammatory papulo-squamous disorder manifesting with palmoplantar keratoderma and follicular hyperkeratotic papules which tend to coalesce into large, scaly, erythematous plaques often progressing to exfoliative erythroderma (Klein et al., 2010; Petrof et al., 2013). PRP is often misdiagnosed as psoriasis, a more common papulo-squamous inflammatory disorder. Nevertheless, the two conditions, in their classic presentations, are clearly distinct, and can be distinguished by clinical findings and histopathologic features (Magro and Crowson, 1997). Clinically, PRP manifests with characteristic “sparing islands ” of apparently normal skin, palmoplantar keratoderma and follicular papules. The disease is frequently self-limiting within a few years ’ timeframe. Histopathology of PRP is characterized by alternating ortho- and parakeratosis rete ridges oriented in vertical and horizontal arrays (“checkerboard pattern”), acanthosis with broadened bases, follicular plugging, perivascular lymphocytic infiltrate in the dermis, and lack of neutrophils in the epidermis. Currently, there is no specific or uniformly effective treatment for PRP. Most cases of PRP are sporadic and without family history, but a familial form with an autosomal dominant inheritance with partial penetrance represents <6 % of al

Pathogenic Connexin-31 Forms Constitutively Active Hemichannels to Promote Necrotic Cell Death

Mutations in Connexin-31 (Cx31) are associated with multiple human diseases including erythrokeratodermia variabilis (EKV). The molecular action of Cx31 pathogenic mutants remains largely elusive. We report here that expression of EKV pathogenic mutant Cx31R42P induces cell death with necrotic characteristics. Inhibition of hemichannel activity by a connexin hemichannel inhibitor or high extracellular calcium suppresses Cx31R42P-induced cell death. Expression of Cx31R42P induces ER stress resulting in reactive oxygen species (ROS) production, in turn, to regulate gating of Cx31R42P hemichannels and Cx31R42P induced cell death. Moreover, Cx31R42P hemichannels play an important role in mediating ATP release from the cell. In contrast, no hemichannel activity was detected with cells expressing wildtype Cx31. Together, the results suggest that Cx31R42P forms constitutively active hemichannels to promote necrotic cell death. The Cx31R42P active hemichannels are likely resulted by an ER stress mediated ROS overproduction. The study identifies a mechanism of EKV pathogenesis induced by a Cx31 mutant and provides a new avenue for potential treatment strategy of the disease

Autoimmune aspects of psoriasis: Heritability and autoantigens

Chronic immune-mediated disorders (IMDs) constitute a major health burden. Understanding IMD pathogenesis is facing two major constraints: Missing heritability explaining familial clustering, and missing autoantigens. Pinpointing IMD risk genes and autoimmune targets, however, is of fundamental importance for developing novel causal therapies. The strongest association of all IMDs is seen with human leukocyte antigen (HLA) alleles. Using psoriasis as an IMD model this article reviews the pathogenic role HLA molecules may have within the polygenic predisposition of IMDs. It concludes that disease-associated HLA alleles account for both missing heritability and autoimmune mechanisms by facilitating tissue-specific autoimmune responses through autoantigen presentation. (C) 2017 The Author. Published by Elsevier B.V