The Pathogenetic Role of IL-1β in Severe Epidermolysis Bullosa Simplex
Journal of Investigative Dermatology (2013) 133, 1901–1903; Dominantly inherited epidermolysis bullosa simplex type Dowling-Meara (EBS-DM) is caused by mutations in either the keratin 5 (K5) or the keratin 14 (K14) gene, which encode the major components of the intermediate filament (IF) network in basal keratinocytes. In healthy keratinocytes, heterodimers of K5 and K14 polymerize to form a cytoplasmic network extending to the cellular periphery and imparting stability to the basal layer of the stratified epithelia. In EBS-DM, causative mutations lead to disintegration and collapse of the IF network, which manifests cytologically as electron-dense aggregates at the periphery of the keratinocyte cytoplasm (Morley et al., 2003). EBS-DM cells exhibit increased fragility to mechanical stress as well as to heat and osmotic shock, making Dowling-Meara the most severe subtype of EBS. As a consequence, EBS-DM patients suffer from blistering and wounding of the skin and mucous membranes after even minor trauma (Stephens et al., 1993; D'Alessandro et al., 2002; Coulombe et al., 2009; Jerabkova et al., 2010). Interestingly, upregulation of K14 at both the transcriptional and protein levels was shown recently in EBS-DM keratinocytes (Wally et al., 2010; Beriault et al., 2012). The JNK/MAPK stress pathway is also known to be upregulated in EBS-DM keratinocytes, and the cells show elevated JNK phosphorylation compared to clinically milder, K14-based EBS subtypes (D'Alessandro et al., 2002). Particularly with regard to a small molecule-based therapeutics, we have focused on the pathomechanism underlying K14 overexpression and aggregation. We have investigated the potential involvement of the pro-inflammatory cytokine IL-1β in EBS-DM pathology. IL-1β is secreted by keratinocytes (and other cell types) and binds to specific receptors of basal keratinocytes, activating those cells in response to wounding. Activated keratinocytes exhibit higher migratory potential and hyperproliferative activity, and secrete extracellular-matrix components and signaling polypeptides to the tissue microenvironment (Freedberg et al., 2001). Defects in these processes could also contribute to the EBS-DM phenotype. To summarize, we showed here that, in EBS-DM keratinocytes, IL-1β signaling is constitutively activated, resulting in activation of the JNK stress pathway and overexpression of K14 and IL-1β itself in a positive feedback loop. Through this mechanism, expression of the dominantly interfering mutated K14 allele would also increase, potentially aggravating the EBS-DM phenotype. Therefore, therapeutic approaches to interrupt this positive feedback loop by inhibiting IL-1β using a neutralizing antibody or diacerein would seem worthwhile. Indeed, treatment of patient keratinocytes with these agents not only reduced the expression levels of K14 and IL-1β and the phosphorylation levels of JNK, but also stabilized the IF network upon heat shock. Our data are further corroborated by our recent demonstration that overall K14 expression levels in EBS-DM keratinocytes are reduced upon mRNA correction via spliceosome-mediated RNA trans-splicing (SMaRT), which shifts the expression ratio of wild-type versus mutated K14 alleles toward wild-type (Wally et al., 2010). We therefore propose that inhibition of IL-1β could be beneficial to EBS-DM patients by ameliorating the EBS-DM phenotype.
安成藥 獲美孤兒藥認定【經濟日報╱記者黃文奇／台北報導】2014.10.22 02:43 am安成藥（4180）昨（21）日宣布，子公司安成生物科技旗下用以治療先天性水皰症（epidermolysis bullosa，EB）的產品AC-201，獲美國食品藥物管理局（FDA）孤兒藥資格認定。安成生技總經理陳志光表示，AC-201用於治療先天性水皰症，該疾病是一種非常罕見的基因突變疾患，換言之，即業界所謂「無適當醫藥可滿足現有需求」的疾病（unmet medical needs）。安成藥昨日股價收233.5元，上漲1.5元。據悉，該種疾病在美國，每5萬名新生嬰兒即有一例先天性水皰症病兒，目前估計在美國已有約3萬名病患，而在台灣也約有數百名病患有這種俗稱「泡泡龍」的惡疾，此疾棘手之處是輕微的摩擦就可能造成患者皮膚上的水泡或裂傷。陳志光表示，希望AC-201的孤兒藥的資格認定能加速此候選藥物的開發。陳志光指出，經皮吸收的AC-201劑型可能用來預防或減少水泡的發生，這樣就可以大大的減輕先天性水皰症患者及其家人的痛苦，因此安成生技也將開始進行AC-201經皮吸收劑型的臨床實驗的程序。【2014/10/22 經濟日報】
Topical diacerein for epidermolysis bullosa: a randomized controlled pilot study Orphanet Journal of Rare Diseases 2013, 8:69 listering in epidermolysis bullosa simplex type Dowling-Meara (EBS-DM) is associated with an inflammatory phenotype, which can be disrupted by diacerein in vitro. In this pilot study we hypothesized, that a topical formulation of diacerein 1% reduces blistering. Five patients initially applied diacerein underneath both armpits. Then, each participant received 1% diacerein-cream for one armpit, and placebo for the other (randomized withdrawal). The number of blisters was reduced significantly (left: -78%; right: -66% of baseline) within two weeks and remained significantly below the initial level even during withdrawal in four patients. These findings point to a relevant effect of diacerein and provide important information for a confirmative study.
EBS-DM is the consequence of dominantly inherited mutations in either the keratin 5 (K5) or keratin 14 (K14) gene, which encode proteins constituting the intermediate filament (IF) network of basal keratinocytes. Mutations lead to an increased mechanical susceptibility of keratinocytes, manifesting in a collapse of the IF network [1]. Clinically, patients suffer from blistering of the skin upon minor trauma, resulting in an impaired quality of life due to pain and pruritus [2]. In vitro studies on EBS-DM keratinocytes showed a significant upregulation of interleukin-1beta (IL-1ß), resulting in the activation of the c-jun N-terminal-kinase (JNK) stress pathway and subsequently in the overexpression of K14 and IL-1ß in a positive feedback loop. When impairing IL-1ß signaling, using anti-IL-1ß antibody or the small molecule diacerein, levels of IL-1ß, JNK and K14 decreased and the IF network was stabilized [3]. Based on this information, we launched a double-blinded, randomized, placebo-controlled pilot study using a 1% diacerein in the commonly used care cream ultraphil® as intervening agent, and ultraphil® alone as placebo. Diacerein, a prodrug of the IL-1 converting enzyme inhibitor rhein, is approved for the systemic treatment of osteoarthritis (Verboril®) [4,5]. It is metabolized in the liver and cleared by the kidneys. Up to now there are no data available on topical application. To test our hypothesis that diacerein is able to reduce blister formation, we recruited five patients (aged 6 to 48) with the diagnosis of EBS-DM and a heterozygous amino acid exchange in K14 protein position 125. An a-priori sample size computation was done in consideration of a 0.90 power, a 5% significance level and a minimum difference between blister numbers of 30%. A 25% standard deviation for the intervention group and 15% for the placebo group was expected. Computation was done for a one-sided, paired student t-test. Including a 10% drop-out rate, the calculation resulted in ten armpits of five patients to be included (Figure 1A). Randomization was done using random numbers, with the general requirement that no patient receives placebo or diacerein on both sides. The two-phased study started with a six-weeks open phase (P1), where all patients received 1% diacerein cream to apply underneath both armpits every evening. Usual care was continued unchanged. Blister numbers were documented every second day by the patients and every second week by a study nurse, who visited the patients at their homes to avoid any influences from travelling or changes of habits. Furthermore, patients were requested to take photos of the blisters plus a tape measure to allow for software aided quantification of blister areas (Figure 1B). To optimize the strength of our small pilot trial we added a second, randomized, placebo-controlled six-weeks phase (P2), exploiting the fact that placebo and verum could be used in parallel in the same patient, which virtually doubled our sample size. Time to loss of efficacy (defined as halving the effect in P1) was chosen as primary endpoint, because this allows minimizing the time on placebo, as patients can be de-blinded and switched to verum as soon as loss of efficacy occurs. For data analysis, we sub-divided the study period into eight time intervals (t), each including six counts (Figure 1C). Patient DIDM005 (1965) did not develop blisters during the study, contradictory to an aforegoing patient inquiry on times of most strain. DIDM005 was therefore excluded from the statistical evaluation. However, it cannot be excluded that the absence of blisters is due to the treatment. As blister numbers are likely to be correlated (two measurements within the same subject), generalized estimation equations (GEE) were used. The group (verum/placebo) was the main effect and time*group was used as interaction effect. The robust method (Huber/White/sandwich estimator) was used for estimating the covariance matrix. Pairwise comparisons are based on the sequential Bonferroni method. The significance level was set to 5%. Results showed a statistically significant reduction of blisters within the first two weeks of P1 (t1: 100%, t2: mean left: 22%/CI6-38; mean right: 34%/CI20-48), which remained stable until the end of the study period (Figure 2A). In P2, we could not observe any loss of efficacy and missed our primary endpoint. Although the relative number of blisters was slightly higher on the placebo sides, there was only a statistically significant difference at t7 (Figure 2B). We believe that carrying-over of the positive effect from P1 into P2 is the reason for that observation. Thus, unless missing the primary statistical objective, the results point to a beneficiary effect of diacerein.