Nahoko Komatsu

A POTENTIAL ROLE FOR MULTIPLE TISSUE KALLIKREIN SERINE PROTEASES IN EPIDERMAL DESQUAMATION

Desquamation of the stratum corneum is a serine protease-dependent process. Two members of the human tissue kallikrein (KLK) family of (chymo)tryptic-like serine proteases, KLK5 and KLK7, are implicated in desquamation by digestion of (corneo)desmosomes and inhibition by desquamation-related serine protease inhibitors (SPIs). However, the epidermal localization and specificity of additional KLKs also supports a role for these enzymes in desquamation. This study aims to delineate the probable contribution of KLK1, KLK5, KLK6, KLK13, and KLK14 to desquamation by examining their interactions, in vitro, with: 1) colocalized SPI, lympho-epithelial Kazal-type-related inhibitor (LEKTI, four recombinant fragments containing inhibitory domains 1–6 (rLEKTI(1–6)), domains 6–8 and partial domain 9 (rLEKTI(6–9′)), domains 9–12 (rLEKTI(9–12)), and domains 12–15 (rLEKTI(12–15)), secretory leukocyte protease inhibitor, and elafin and 2) their ability to digest the (corneo)desmosomal cadherin, desmoglein 1. KLK1 was not inhibited by any SPI tested. KLK5, KLK6, KLK13, and KLK14 were potently inhibited by rLEKTI(1–6), rLEKTI(6–9′), and rLEKTI(9–12) with Ki values in the range of 2.3–28.4 nm, 6.1–221 nm, and 2.7–416 nm for each respective fragment. Only KLK5 was inhibited by rLEKTI(12–15) (Ki = 21.8 nm). No KLK was inhibited by secretory leukocyte protease inhibitor or elafin. Apart from KLK13, all KLKs digested the ectodomain of desmoglein 1 within cadherin repeats, Ca2+ binding sites, or in the juxtamembrane region. Our study indicates that multiple KLKs may participate in desquamation through cleavage of desmoglein 1 and regulation by LEKTI. These findings may have clinical implications for the treatment of skin disorders in which KLK activity is elevated.

Human tissue kallikrein expression in the stratum corneum and serum of atopic dermatitis patients.

Abstract:  Human tissue kallikreins are a family of 15 trypsin‐ or chymotrypsin‐like secreted serine proteases (KLK1–KLK15). Many KLKs have been identified in normal stratum corneum (SC) and sweat, and are candidate desquamation‐related proteases.

Multiple tissue kallikrein mRNA and protein expression in normal skin and skin diseases

Background  Human tissue kallikreins are a gene family (KLK1–KLK15) encoding for 15 secretory serine proteases (hK1–hK15). Two tissue kallikrein proteins, hK5 and hK7, were previously found in the stratum corneum (SC), stratum granulosum (SG) and appendages. hK8 was also shown to be secreted via lamellar granules and numerous KLK mRNAs were previously identified. KLKs are believed to be responsible for desquamation of corneocytes and sebum, sweat and hair maturation.

Aberrant human tissue kallikrein levels in the stratum corneum and serum of patients with psoriasis: dependence on phenotype, severity and therapy

Background  Human tissue kallikreins (KLKs) are a family of 15 trypsin‐like or chymotrypsin‐like secreted serine proteases (KLK1–KLK15). Multiple KLKs have been quantitatively identified in normal stratum corneum (SC) and sweat as candidate desquamation‐related proteases.

Human tissue kallikreins: from gene structure to function and clinical applications.

Publisher Summary Kallikreins are expressed in many organs, most prominently in endocrine-related tissues such as the prostate, breast, ovary, uterus, vagina, and testis. The coexpression of many kallikreins in several cancer types and other information pointing to the possibility of their involvement in a cascade-like pathway that may be associated with cancer pathogenesis or progression are presented in this chapter. Characterization and sequence analysis of human-tissue kallikrein gene locus are discussed in this chapter. A short historical perspective of the discovery of human-tissue kallikrein gene locus is presented in this chapter. Kallikreins in rodents and other species such as the mouse kallikrein gene family, the rat kallikrein gene family, and the dog kallikrein gene family are also described in this chapter. Structural features of human-tissue kallikrein genes and proteins such as common structural features and three-dimensional structure are also presented in this chapter. Sequence variations of human kallikrein genes, the tissue kallikreins in the context of other serine proteases in the human genome, tissue expression and cellular localization of the kallikrein genes, regulation of kallikrein activity (at the mRNA level, at the protein level, locus control of kallikrein expression, and epigenetic regulation of kallikrein gene expression), hormonal regulation of kallikreins, and evolution of kallikreins are also presented in this chapter. Prognostic and predictive value of kallikreins in hormone-dependent cancers such as ovarian cancer, breast cancer, and prostate cancer is also described in this chapter. The enzymatic activity of these serine proteases may initiate or terminate biological events. A third possible therapeutic approach involves immunotherapy or development of cancer vaccines. With increasing knowledge of the hormonal regulation of kallikreins, hormonal activation (or repression) of kallikrein activity could be investigated in the future.

Abundant expression of Kallikrein 1 gene in human keratinocytes was mediated by GATA3.

Among Tissue kallikrein genes (KLKs), KLK1 is abundantly expressed in human skin. Although its putative promoter is known to have various cis-elements, they have not been functionally tested. In the present study, the regulation mechanism of KLK1 promoter supporting such abundant expression was examined. Luciferase assay targeting the KLK1 promoter (nucleotide -1153/+40 from the major transcriptional start site) was performed on NHEK human keratinocyte. -954/-855, -428/-236, and -100/+40 had the induction activity. The motif search program failed to find unique binding motifs in -428/-236, whereas both -954/-855 and -100/+40 had a unique GATAs binding motif. Electrophoretic mobility shift assay (EMSA) and DNA footprinting confirmed the binding of NHEK nuclear protein to these motifs that were supershifted by anti-GATA3 antibody. Among GATA isoforms, GATA3 alone could be amplified in RNA obtained from NHEK. Moreover, introduction of GATA3 into fibroblastic NIH3T3 cells enhanced the activity of KLK1 promoter containing -954/+40, while that of GATA3 dominant negative mutant to NHEK cells impaired the same promoters activity. Thus, GATA3 was found to bind the site located at -954/-855 and to be a key regulator of abundant KLK1 expression in human keratinocyte.

A case of peeling skin syndrome successfully treated with topical calcipotriol

Dear Editor, A 9-year-old Japanese girl visited our hospital for evaluation of generalized scaly erythroderma. Her parents stated that she had suffered since birth from the emergence of irregular patches, mainly on the trunk and extremities, characterized by peeling sheets of epidermis and associated with pruritus and/or a burning sensation (Fig. 1a,b). The patches were edged by a rough border that developed after several days of scratching and rubbing. Sheets of superficial epidermis could easily be peeled without bleeding or pain (Fig. 1b). She did not reveal obvious desquamation and hyperkeratosis in palmoplantar lesions. However, her scalp was covered with small, fine scales. Repeated examination of the hairs on her scalp and superciliary regions failed to reveal any evidence of trichorrhexis invaginata, pili torti or other hair abnormalities. She was below the second percentile for her age group in both height and weight. Laboratory tests gave normal results except for leukocytosis (16 700 × 10 9 /L) with hyper-eosinophilia (5929/ul), and high serum levels of immunoglobulin (Ig)E (11 676 IU/ml) and lactate dehydrogenase (LDH) (797 IU/ l). Radioallergosorbent tests (RAST) performed to assess food allergies showed that she was highly allergic to egg white, wheat, bovine meat (class 5) and to cow’s milk, egg yolk, barley, rice and chicken meat (class 4). No other abnormalities were found by physical and radiological examinations. There was no parental consanguinity. We performed a punch biopsy of the affected skin from a lesion on the buttock for microscopic examination. Histopathological examination of the biopsy specimen showed parakeratosis and psoriasiform acanthosis with a superficial perivascular infiltrate. Ultrastructural analysis showed premature shedding of the stratum corneum immediately above the granular cell layer (Fig. 1d,e). The presence of scaly erythroderma and atopic diathesis suggested a diagnosis of Netherton’s syndrome (NS), shown to be associated with mutations in the SPINK5 gene. 1,2 However, some other clinical features, notably the lack of hair abnormalities and the absence of scale formation as “ichthyosis linearis circumflexa”, were inconsistent with this diagnosis. We extracted genomic DNA from the patient’s white blood cells and sequenced the entire SPINK5 coding region and exon-intron borders as previously described, 1 but found no mutational changes. The failure to show any association with mutations in the SPINK5 gene 1,2 by DNA analysis did not support a diagnosis of NS. Therefore, based on the characteristic clinical features such as superficial skin peeling, a published work review and a comparison with other Japanese cases, we diagnosed her as having peeling skin syndrome (PSS). 3,4

A case of a Japanese neonate with congenital ichthyosiform erythroderma diagnosed as Netherton syndrome.

We report a 6‐day‐old Japanese girl showing generalized erythroderma accompanied by yellowish, exfoliative scaling that was accentuated on the face and scalp. Histological analysis showed psoriasiform dermatitis with acanthotic epidermis and premature shedding of the stratum corneum. Measurement of trypsin‐like hydrolytic activity in SC showed six‐fold greater activity compared with age‐matched controls. DNA analysis revealed two mutations, 375delAT and 966insC, in exons 5 and 11, respectively, of the SPINK5 gene. Although at 4 weeks the child was still too young to display characteristic hair abnormalities or atopic diathesis, we diagnosed Netherton syndrome based on enzyme assay and DNA analysis.