Su M. Lwin

Potential of Systemic Allogeneic Mesenchymal Stromal Cell Therapy for Children with Recessive Dystrophic Epidermolysis Bullosa

TO THE EDITOR The skin fragility disorder, recessive dystrophic epidermolysis bullosa (RDEB) results from mutations in COL7A1, leading to reduced or absent type VII collagen (C7) and defective anchoring fibrils at the dermal–epidermal junction (Fine et al., 2014). Currently, there is no cure, and most individuals develop lifeshortening squamous cell carcinomas (Fine and Mellerio, 2009). RDEB also has a major health economic burden; wound dressings for a 10-year-old child can cost

Beneficial effect of ustekinumab in familial pityriasis rubra pilaris with a new missense mutation in CARD14

680 per day (Kirkorian et al., 2014), which equates to 4

Gene Therapy for Inherited Skin Disorders

250,000 annually. Reported clinical trials of cell-based therapies for RDEB comprise intradermal allogeneic fibroblasts (Petrof et al., 2013; Venugopal et al., 2013), bone marrow transplantation (Wagner et al., 2010), intradermal bone marrow– derived mesenchymal stromal cells (BM-MSCs) (Conget et al., 2010), and intravenous BM-MSCs in RDEB adults (El-Darouti et al., 2013; abstract only). Ex vivo COL7A1 keratinocyte gene therapy is also being evaluated (Siprashvili et al., 2014). MSCs are heterogeneous cells that undergo self-renewal or differentiate into mesenchymal lineages (Caplan, 1991). MSCs also have non-progenitor functions in immune regulation, cell growth, and tissue repair (Phinney and Prockop, 2007; Chen et al., 2008). Nevertheless, healing is not associated with large numbers of therapeutic MSCs in injured tissues, suggesting that paracrine benefits may modulate inflammatory and immune responses (Baraniak and McDevitt, 2010). Our interest focuses on the potential of intravenous allogeneic BM-MSCs to help people living with RDEB. Ten children were included in the clinical trial and are detailed in Supplementary Table S1 online, with the trial protocol shown in Supplementary Figure S1 online. The trial was approved by the UK Medicines and Healthcare Products Regulatory Agency, with EudraCT number: 2012-001394-87; the UK National Research Ethics Committee London-Bloomsbury provided ethics approval (Ref:12/LO/1258), and the trial was registered prospectively with www. controlled-trials.com ISRCTN46615946. Written informed consent was obtained for each subject. Inclusion/exclusion criteria are presented in Supplementary Table S2 online, and study interventions are listed in Supplementary Table S3 online. Details of the BM-MSCs are provided in Supplementary Table S4 online. Each participant received three intravenous infusions of BM-MSCs (day 0, 7, and 28; each dose 1–3×10 cells kg) with no HLA matching or pre-conditioning. With regard to safety, there were 163 adverse events (AEs; Supplementary Tables S5–S7 online). Initially, two serious AEs, esophageal dilatation and skin infection, were reported but were subsequently downgraded (protocol version 4.0, 1 August 2014), as they were considered to be complications of RDEB and not the cells. Indeed, 127/163 (78%) of AEs were either unlikely or not related to the BM-MSCs. Concerning the severity of MSCrelated AEs, there were two severe events of DMSO odor, although odor was noted following 28/30 infusions (lasting up to 48 hours). Mild nausea occurred during two infusions, and abdominal pain and bradycardia were observed during two other infusions; all resolved within 15 minutes without treatment or hemodynamic compromise. No AEs resulted in discontinuation of MSCs. Laboratory assessments did not reveal any adverse impact of the BM-MSCs on renal, liver, or bone marrow function. Anti-C7 antibodies were detected by ELISA at baseline in 9/10 participants, but no sera bound to the dermal–epidermal junction by indirect immunofluorescence microscopy. Following MSCs, there were no changes in ELISA or indirect immunofluorescence microscopy data (Supplementary Table S8 online). Collectively, the tolerance data appear encouraging, although it should be noted that a zero event rate for a serious AE in just 10 patients is compatible with an upper 95% confidence interval of over 30%. With regard to secondary outcome measures, the data are summarized in Supplementary Table S9 online. Skin biopsies revealed no increase in C7 and no new anchoring fibrils at day 60. Fluorescence in situ hybridization analysis did not show donor-cell chimerism. Birmingham epidermolysis bullosa severity score (BEBSS) and global severity score questionnaires were completed for all the 10 participants (Supplementary Figures S2 and S3 online). Mean parentreported pain score was lower at 60 days than at baseline (mean difference: −5.5 points; 95% confidence interval (CI): LETTERS TO THE EDITOR

261 Tissue and circulating microRNA co-expression analysis reveals potential involvement of miRNAs in the pathobiology of frontal fibrosing alopecia

Pityriasis rubra pilaris (PRP) represents a group of rare chronic inflammatory skin disorders in which around one in 20 affected individuals show autosomal dominant inheritance. In such cases there may be gain‐of‐function mutations in CARD14, encoding caspase recruitment domain‐containing protein 14 (CARD14), which activates the noncanonical nuclear factor (NF)‐κB pathway, thereby promoting cutaneous inflammation. Here we report a mother and son with PRP due to a new missense mutation in CARD14 and describe the beneficial clinical effects of ustekinumab, a monoclonal antibody against interleukins 12 and 23, in both patients. A 49‐year‐old woman and her 20‐year‐old son had lifelong, generalized, patchy erythematous scale with a few islands of sparing, as well as minor nail ridging and mild palmoplantar keratoderma, features consistent with generalized PRP. Topical steroids, phototherapy and oral retinoids proved ineffective. Following informed consent, Sanger sequencing of CARD14 in both individuals revealed a new heterozygous single‐nucleotide transversion in exon 4, c.356T>G, resulting in the missense mutation p.Met119Arg. Ustekinumab, at a dose of 45 mg every 12 weeks, brought about a significant physical and emotional improvement in both the mother and son within a few days of the initial dose, which was sustained on maintenance dosing. This report highlights the therapeutic potential of biologics that downregulate NF‐κB signalling in familial PRP with mutations in CARD14.

APOBEC mutation drives early-onset squamous cell carcinomas in recessive dystrophic epidermolysis bullosa

Inherited skin disorders are caused by pathogenic mutations in over 500 genes. These mutations result in a spectrum of cutaneous and systemic abnormalities that generate considerable morbidity, and occasionally mortality. To date, however, there are no effective treatments. Nevertheless, the easy accessibility of skin, together with advances in molecular genetics and biotechnology, has paved the way for gene therapy development and testing. Gene therapy aims to reverse the pathology and phenotype of a particular disease through supplementation of the defective gene with a single normal full-length copy or correction of the underlying mutant gene via genome editing or RNA (ribonucleic acid)-based methods. Key Concepts Inherited skin disorders (also known as genodermatoses) encompass a group of genetic skin diseases in which single- or multiple-gene defects account for a wide spectrum of clinical phenotypes with significant physical and psychosocial impact. Epidermolysis bullosa (EB) is a diverse group of autosomal dominant and recessive blistering skin diseases that affects ∼500 000 people worldwide. In EB, relatively minor trauma to the skin causes blistering which can be complicated by delayed healing and scarring. There is a desperate clinical need for effective therapies, including gene therapy. Gene therapy involves manipulation of cellular DNA or RNA to provide therapeutic benefit using various strategies. These include gene modification through gene addition or replacement, and gene correction through RNA-based technologies or genome editing tools. Single-gene disorders are therefore good candidates for gene therapy. The choice of gene therapy strategy in genodermatoses depends on the mode of inheritance and the nature of the pathogenic mutations of a particular disorder. Given that most autosomal recessive skin disorders result in loss of function, deficiency or absence of the wild-type protein, restoring protein function through the addition of a wild-type copy of the mutant gene, or correction of the mutant gene, is an appropriate therapeutic goal. In contrast, heterozygous mutations in dominant skin disorders typically result in dominant-negative interference of the mutant/wild-type proteins. Thus, therapeutic benefits are best sought by knockdown/silencing of the mutant allele while preserving the functional wild-type allele, through applying gene correction techniques using small interfering RNA (siRNA) or gene editing endonucleases. Keywords: skin; genodermatoses; epidermolysis bullosa; gene therapy; gene addition; gene correction; gene editing; vector; lentivirus; retrovirus

Ichthyosis Prematurity Syndrome: From Fetus to Adulthood

Citing this paper Please note that where the full-text provided on Kings Research Portal is the Author Accepted Manuscript or Post-Print version this may differ from the final Published version. If citing, it is advised that you check and use the publishers definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publishers website for any subsequent corrections.

Melanin distribution in human epidermis affords localized protection against DNA photodamage and concurs with skin cancer incidence difference in extreme phototypes

Early-onset squamous cell carcinoma in recessive dystrophic epidermolysis bullosa patients is characterized by APOBEC mutagenesis. Mutational signature sleuthing Individuals with the inherited skin disease recessive dystrophic epidermolysis bullosa (RDEB) are predisposed to developing aggressive squamous cell carcinomas (SCCs), although why this patient group is prone to these cancers at such early ages is unknown. Cho et al. sequenced multiple RDEB SCC tumors and found that the mutation profile in these carcinomas was most consistent with APOBEC-associated mutagenesis, unlike other types of SCC that may be driven by ultraviolet light or tobacco smoke exposure. This finding could open up new lines of thinking on how to successfully prevent or target SCCs in RDEB patients. Recessive dystrophic epidermolysis bullosa (RDEB) is a rare inherited skin and mucous membrane fragility disorder complicated by early-onset, highly malignant cutaneous squamous cell carcinomas (SCCs). The molecular etiology of RDEB SCC, which arises at sites of sustained tissue damage, is unknown. We performed detailed molecular analysis using whole-exome, whole-genome, and RNA sequencing of 27 RDEB SCC tumors, including multiple tumors from the same patient and multiple regions from five individual tumors. We report that driver mutations were shared with spontaneous, ultraviolet (UV) light–induced cutaneous SCC (UV SCC) and head and neck SCC (HNSCC) and did not explain the early presentation or aggressive nature of RDEB SCC. Instead, endogenous mutation processes associated with apolipoprotein B mRNA-editing enzyme catalytic polypeptide–like (APOBEC) deaminases dominated RDEB SCC. APOBEC mutation signatures were enhanced throughout RDEB SCC tumor evolution, relative to spontaneous UV SCC and HNSCC mutation profiles. Sixty-seven percent of RDEB SCC driver mutations was found to emerge as a result of APOBEC and other endogenous mutational processes previously associated with age, potentially explaining a >1000-fold increased incidence and the early onset of these SCCs. Human papillomavirus–negative basal and mesenchymal subtypes of HNSCC harbored enhanced APOBEC mutational signatures and transcriptomes similar to those of RDEB SCC, suggesting that APOBEC deaminases drive other subtypes of SCC. Collectively, these data establish specific mutagenic mechanisms associated with chronic tissue damage. Our findings reveal a cause for cancers arising at sites of persistent inflammation and identify potential therapeutic avenues to treat RDEB SCC.

738 Safety outcomes for first-in-man intradermal injections of lentiviral-engineered COL7A1-supplemented autologous fibroblasts in adults with recessive dystrophic epidermolysis bullosa: International Investigative Dermatology (IID) 2018 Meeting Abstract SupplementInternational Investigative Dermatology (IID) 2018

Citing this paper Please note that where the full-text provided on Kings Research Portal is the Author Accepted Manuscript or Post-Print version this may differ from the final Published version. If citing, it is advised that you check and use the publishers definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publishers website for any subsequent corrections.