Reb Watson

Topical ALA-PDT produces an inflammatory infiltrate but reduces Langerhans cells in healthy human skin in vivo

Background  Topical photodynamic therapy (PDT) elicits a therapeutic response in both skin cancer and immune‐mediated skin disorders. While PDT induces direct cell death, host inflammatory and immune responses to PDT may contribute to the therapeutic effects.

Review Article: A new wrinkle on old skin: the role of elastic fibres in skin ageing

Cutaneous ageing is the result of two distinct, biological processes which may occur concurrently: (i) the passage of time, termed intrinsic ageing and (ii) environmental influences, termed extrinsic ageing. Intrinsic ageing of the skin is a slow process which causes changes in tissue structure and impairs function in the absence of additional biological, chemical and physical factors. The clinical features of intrinsically aged skin are not usually evident until old age when, although smooth and unblemished, the skin surface appears pale and is characterized by fine wrinkles with occasional exaggerated expression lines. Functionally, intrinsically aged skin is dry and less elastic than more youthful skin. In contrast, extrinsically aged skin is exemplified by deep, coarse wrinkles, mottled hyperpigmentation and a marked loss of elasticity and recoil. The two major environmental influences which induce extrinsic ageing are: (i) chronic exposure to solar ultraviolet (UV) irradiation (termed photoageing) and (ii) smoking. This review discusses the changes associated with the ageing process in the skin, with particular emphasis on the role played by the elastic fibre network in maintaining dermal function. The review concludes with a discussion of a short‐term assay for independent assessment of the efficacy of anti‐ageing cosmetic products using the elastic fibre component fibrillin‐1 as a biomarker of extracellular matrix repair.

Aged human skin accumulates mast cells with altered functionality which localise to macrophage and VIP+ nerve fibres

Skin health declines with age and this is partially attributed to immunosenescence. Mast cells (MCs) are innate immune cells that coordinate tissue immune responses integral to skin homeostasis and disease.

Role of memory effector T lymphocytes in the early phase of photosensitive psoriasis.

The transfer of normal genes into somatic cells is one strategy to treat patients with genetic diseases. However, this strategy has still encounters technical problems including effi cacy of gene transfer rate and practical clinical safety. Thus, other strategies including pharmacological therapy or gene correction, are receiving increasing attention. Dystrophic epidermolysis bullosa (DEB) is caused by mutations in the COL7A1 encoding type VII collagen. This study examined the feasibility of antisense oligoribonucleotide (AON) therapy for DEB. AON was designed to induce skipping of a targeted exon containing a premature termination codon mutation, resulting in restoration of the open reading frame. We targeted exon 70 of COL7A1 since a recurrent mutation 5818delC was localized to exon 70 in Japanese DEB patients. We initially designed and synthesized two AONs to modulate splicing of exon 70 and found that one AON induced effective skipping of normal exon 70 containing the 16 amino acids. Attachment and migration analyses showed that recombinant collagen without contribution of exon 70 had similar effect to normal type VII collagen. Next, we synthesized mutation-specifi c AON by deleting cytosine at 5818. Introduction of this AON into DEB keratinocytes harboring 5818delC without expression of type VII collagen showed that the AON induced skipping of exon 70 in the abnormal 5818delC allele. Furthermore, 6.2 % of the DEB keratinocytes started to express type VII collagen in vitro after application of the mutation-specifi c AON. Injection of the AON into rat model grafted the DEB keratinocytes and fi broblasts induced detectable of type VII collagen expression at the basement membrane zone. We conclude that skipping of targeted exons using mutation-specifi c AON may show potential for future gene therapy for DEB patients.We recently reported that ABCA12 works as an epidermal keratinocyte lipid transporter, and that defective ABCA12 results in a loss of the skin lipid barrier, leading to harlequin ichthyosis (HI), one of the most devastating genodermatoses. In the present study, precise expression pattern of ABCA12 was studied in human embryonic and fetal skin of 7-22 weeks estimated gestational age (EGA) and newborn skin samples. For controls, we also studied the expression of transglutaminase 1 (TGase1) that is known to cross-link several precursor proteins in the formation of the cornifi ed cell envelope during keratinocyte terminal differentiation. In twolayered epidermis (about 6-9 weeks EGA), both ABCA12 and TGase1 were only expressed in periderm cells. In three-layered epidermis (10-13 weeks EGA), ABCA12 staining was seen not only in periderm, but also throughout the entire epidermis, while TGase1 staining was restricted to the periderm. A similar pattern was observed during four- or more-layered epidermal development (14-22 weeks EGA). In newborn skin, ABCA12 and TGase1 were seen only in the upper epidermal layers, mainly the granular layer. These staining patterns were similar to those in normal adult skin. Next, we studied ABCA12 mRNA expression in extracts of the fetal skin (at 10, 14, 15 weeks EGA). In 15 weeks EGA, the expression level of ABCA12 mRNA was signifi cantly increased compared with that in the early development (10 and 14 weeks EGA). This increasing pattern of ABCA12 mRNA expression is consistent with ABCA12 immunofl uorescent staining during human epidermal development. The unique pattern of ABCA12 expression during human epidermal development might imply severe symptoms of HI patients with ABCA12 mutations around the birth. 2006 ESDR ABSTRACTS www.Mutations in ABCA12 lead to harlequin ichthyosis and lamellar ichthyosis. The keratinocyte lipid transporter ABCA12 is a member of the ATP-binding cassette transporter family, and members of the ABCA subfamily have closely related functions as lipid transporters. Previously, we reported that the pathomechanism of harlequin ichthyosis involves the defective function of the lipid transporter ABCA12.To further elucidate the precise distribution pattern and function of ABCA12, we performed double-labeling immunofl uorescence staining for ABCA12 and for Golgi-associated or lamellar granule-associated molecules both on normal human epidermis and cultured normal human keratinocytes. We studied the precise localization of ABCA12 and other molecules using confocal laser scanning microscope. In normal human epidermis, ABCA12 was observed mainly in the granular layers with glucosylceramide (one of the major lamellar granule contents) and transglutaminase 1 (a cornifi ed cell envelope-associated keratinization marker), but not always colocalized with GM130 and TGN46 (Golgi-related molecules) that were expressed from the lower epidermis. In normal human keratinocytes cultured in high Ca++ concentration medium, ABCA12 colocalized with GM130 (a cis-Golgi- associated molecule), TGN46 (a trans-Golgi-associated molecule) and glucosylceramide. Transglutaminase 1 was restricted to the cell membrane and ABCA12 localization was within the cytoplasm distinct from transglutaminase 1 localization. The present results suggest that ABCA12 is mainly expressed in differentiated, granular layer keratinocytes with glucosylceramide and transglutaminase 1, and, at the subcellular level, ABCA12 is distributed from the cisside of the Golgi apparatus to trans-Golgi network, lamellar granules at the cell periphery. Our results suggest that ABCA12 may play an important role in lipid transport from the cis-side of the Golgi apparatus through the trans-Golgi network, to the cell periphery via lamellar granules in human epidermal granular layer keratinocytesHarlequin ichthyosis (HI) is a devastating genodermatosis that is often fatal during the neonatal period. Until the identifi cation of ABCA12-encoding a keratinocyte lipid transporter, as the causative gene for HI, prenatal diagnosis (PNDx) had been performed for more than 20 years by electron microscopic examination of fetal skin biopsy samples. We report here the fi rst case of DNA-based PNDx for HI. The proband, the fi rst child of healthy non-consanguineous French parents, showed a typical HI phenotype and died soon after birth. ABCA12 immunostaining was markedly reduced in the proband’s skin. Direct sequence analysis of ABCA12 revealed that the proband was a compound heterozygote for two novel mutations: a maternal nonsense mutation p.Ser1249X in exon 26 and a paternal missense mutation p.Arg2479Lys occurring at the last codon of exon 50. p.Ser1249X leads to an approximate 52 % truncation of the ABCA12 protein losing both ATP-binding cassette active sites. p.Arg2479Lys involves a highly conserved codon among diverse species in the second ABCA12 ATP-binding cassette. For their third pregnancy, the parents requested PNDx. Direct sequence analysis using fetal genomic DNA from amniotic fl uid cells at 17 weeks of pregnancy revealed that the fetus was a compound heterozygote for both mutations. The fetus was predicted to be affected and the parents requested the pregnancy to be terminated. The aborted fetus showed typical signs of HI. Analysis of ABCA12 transcripts of cultured keratinocytes from the abortus showed the presence of six abnormally spliced products arising from the allele carrying the missense mutation. Four of them lead to premature termination codons while the two others produced deleted proteins missing 21 and 31 amino acids in the second ATP-binding cassette. These results indicated residual expression of ABCA12. The present report paves the way for molecular PNDx of HI in the earlier stages of pregnancy