Elevated stratum corneum hydrolytic activity in Netherton syndrome suggests an inhibitory regulation of desquamation by SPINK5-derived peptides

Diosmetin as a promising natural therapeutic agent: In vivo, in vitro mechanisms, and clinical studies

Diosmetin, a natural occurring flavonoid, is primarily found in citrus fruits, beans, and other plants. Diosmetin demonstrates a variety of pharmacological activities, including anticancer, antioxidant, anti-inflammatory, antibacterial, metabolic regulation, cardiovascular function improvement, estrogenic effects, and others. The process of literature search was done using PubMed, Web of Science and ClinicalTrials databases with search terms containing Diosmetin, content, anticancer, anti-inflammatory, antioxidant, pharmacological activity, pharmacokinetics, in vivo, and in vitro. The aim of this review is to summarize the in vivo, in vitro and clinical studies of Diosmetin over the last decade, focusing on studies related to its anticancer, anti-inflammatory, and antioxidant activities. It is found that DIO has significant therapeutic effects on skin and cardiovascular system diseases, and its research in pharmacokinetics and toxicology is summarized. It provides the latest information for researchers and points out the limitations of current research and areas that should be strengthened in future research, so as to facilitate the relevant scientific research and clinical application of DIO.

Two Incidental Sibling Diagnoses of Netherton Syndrome in Separate Visits: A Case Report

Netherton syndrome (NTS) is a genetic disorder that predominantly affects the hair and the skin, and it can have a wide variety of presentations. The genetic syndrome is more common with consanguineous parents. Given the rarity and varying presentation of the condition, a few cases have been reported in the literature. We present an unusual case of two incidental diagnoses of NTS in siblings of consanguineous parents, manifesting as erythroderma and other symptoms that were initially diagnosed as pityriasis rubra pilaris and psoriasis in separate visits. Physicians must maintain a high index of suspicion when faced with chronic skin conditions and hair shaft abnormalities that may have been present since childhood to avoid the sequela of inadvertent prolonged or misdiagnosis.

Comparative analyses of Netherton syndrome patients and Spink5 conditional knock-out mice uncover disease-relevant pathways

Netherton syndrome (NS) is a rare skin disease caused by loss-of-function mutations in the serine peptidase inhibitor Kazal type 5 (SPINK5) gene. Disease severity and the lack of efficacious treatments call for a better understanding of NS mechanisms. Here we describe a novel and viable, Spink5 conditional knock-out (cKO) mouse model, allowing to study NS progression. By combining transcriptomics and proteomics, we determine a disease molecular profile common to mouse models and NS patients. Spink5 cKO mice and NS patients share skin barrier and inflammation signatures defined by up-regulation and increased activity of proteases, IL-17, IL-36, and IL-20 family cytokine signaling. Systemic inflammation in Spink5 cKO mice correlates with disease severity and is associated with thymic atrophy and enlargement of lymph nodes and spleen. This systemic inflammation phenotype is marked by neutrophils and IL-17/IL-22 signaling, does not involve primary T cell immunodeficiency and is independent of bacterial infection. By comparing skin transcriptomes and proteomes, we uncover several putative substrates of tissue kallikrein-related proteases (KLKs), demonstrating that KLKs can proteolytically regulate IL-36 pro-inflammatory cytokines. Our study thus provides a conserved molecular framework for NS and reveals a KLK/IL-36 signaling axis, adding new insights into the disease mechanisms and therapeutic targets.

Skin Barrier Function: The Interplay of Physical, Chemical, and Immunologic Properties

An intact barrier function of the skin is important in maintaining skin health. The regulation of the skin barrier depends on a multitude of molecular and immunological signaling pathways. By examining the regulation of a healthy skin barrier, including maintenance of the acid mantle and appropriate levels of ceramides, dermatologists can better formulate solutions to address issues that are related to a disrupted skin barrier. Conversely, by understanding specific skin barrier disruptions that are associated with specific conditions, such as atopic dermatitis or psoriasis, the development of new compounds could target signaling pathways to provide more effective relief for patients. We aim to review key factors mediating skin barrier regulation and inflammation, including skin acidity, interleukins, nuclear factor kappa B, and sirtuin 3. Furthermore, we will discuss current and emerging treatment options for skin barrier conditions.

Structural variation and introgression from wild populations in East Asian cattle genomes confer adaptation to local environment

BACKGROUND

Structural variations (SVs) in individual genomes are major determinants of complex traits, including adaptability to environmental variables. The Mongolian and Hainan cattle breeds in East Asia are of taurine and indicine origins that have evolved to adapt to cold and hot environments, respectively. However, few studies have investigated SVs in East Asian cattle genomes and their roles in environmental adaptation, and little is known about adaptively introgressed SVs in East Asian cattle.

RESULTS

In this study, we examine the roles of SVs in the climate adaptation of these two cattle lineages by generating highly contiguous chromosome-scale genome assemblies. Comparison of the two assemblies along with 18 Mongolian and Hainan cattle genomes obtained by long-read sequencing data provides a catalog of 123,898 nonredundant SVs. Several SVs detected from long reads are in exons of genes associated with epidermal differentiation, skin barrier, and bovine tuberculosis resistance. Functional investigations show that a 108-bp exonic insertion in SPN may affect the uptake of Mycobacterium tuberculosis by macrophages, which might contribute to the low susceptibility of Hainan cattle to bovine tuberculosis. Genotyping of 373 whole genomes from 39 breeds identifies 2610 SVs that are differentiated along a "north-south" gradient in China and overlap with 862 related genes that are enriched in pathways related to environmental adaptation. We identify 1457 Chinese indicine-stratified SVs that possibly originate from banteng and are frequent in Chinese indicine cattle.

CONCLUSIONS

Our findings highlight the unique contribution of SVs in East Asian cattle to environmental adaptation and disease resistance.

Netherton syndrome in a Bulgarian patient : Presentation of a case and an update of therapeutic options

Comel-Netherton syndrome, or Netherton syndrome (NS), is a rare chronic genetic skin condition affecting the daily life of patients, which often results in poorly developed social skills and anxiety. Genetic predisposition plays a key role alongside the clinical findings, and clinicians must be aware of it as it can mimic other well-known skin conditions. Diagnosis is challenging both clinically and histologically. Clinically, it can mimic a severe form of atopic dermatitis, psoriasiform dermatitis overlapping with atopic dermatitis, or erythrokeratodermia variabilis. The difficulties in making histological diagnosis are similar, and it is often necessary to take several biopsies in order to clarify the diagnosis. Although retinoids are used for both psoriasis, erythrokeratodermia variabilis, and other congenital forms of keratodermia, the recommended treatment doses are different. This often results in poor treatment outcome. We present a 16-year-old patient previously diagnosed as erythrokeratodermia variabilis and treated with little to no improvement. Systemic therapy with acitretin 10 mg daily, local pimecrolimus 1%, emollients, and bilastine 20 mg once daily was initiated. Due to the limited application of retinoids and the difficulties in achieving permanent remission, modern medicine is faced with the challenge of seeking innovative therapeutic solutions. New hopes are placed on targeted or anti-cytokine therapy, based on inhibiting the inflammatory component of the disease. This article is mainly focused on innovative therapeutic options, including modern medications such as dupilumab, infliximab, secukinumab, anakinra, omalizumab, and others.

Skin barrier immunology from early life to adulthood

Our skin has a unique barrier function, which is imperative for the body's protection against external pathogens and environmental insults. Although interacting closely and sharing many similarities with key mucosal barrier sites, such as the gut and the lung, the skin also provides protection for internal tissues and organs and has a distinct lipid and chemical composition. Skin immunity develops over time and is influenced by a multiplicity of different factors, including lifestyle, genetics, and environmental exposures. Alterations in early life skin immune and structural development may have long-term consequences for skin health. In this review, we summarize the current knowledge on cutaneous barrier and immune development from early life to adulthood, with an overview of skin physiology and immune responses. We specifically highlight the influence of the skin microenvironment and other host intrinsic, host extrinsic (e.g. skin microbiome), and environmental factors on early life cutaneous immunity.

The family of kallikrein-related peptidases and kinin peptides as modulators of epidermal homeostasis

The epidermis is the outermost skin layer and is part of one of the largest organs in the body; it is supported by the dermis, a network of fibrils, blood vessels, pilosebaceous units, sweat glands, nerves, and cells. The skin as a whole is a protective shield against numerous noxious agents, including microorganisms and chemical and physical factors. These functions rely on the activity of multiple growth factors, peptide hormones, proteases, and specific signaling pathways that are triggered by the activation of distinct types of receptors sited in the cell membranes of the various cell types present in the skin. The human kallikrein family comprises a large group of 15 serine proteases synthesized and secreted by different types of epithelial cells throughout the body, including the skin. At this site, they initiate a proteolytic cascade that generates the active forms of the proteases, some of which regulate skin desquamation, activation of cytokines, and antimicrobial peptides. Kinin peptides are formed by the action of plasma and tissue kallikreins on kininogens, two plasma proteins produced in the liver and other organs. Although kinins are well known for their proinflammatory abilities, in the skin they are also considered important modulators of keratinocyte differentiation. In this review, we summarize the contributions of the kallikreins and kallikrein-related peptidases family and those of kinins and their receptors in skin homeostasis, with special emphasis on their pathophysiological role.

Lobelia chinensis Extract and Its Active Compound, Diosmetin, Improve Atopic Dermatitis by Reinforcing Skin Barrier Function through SPINK5/LEKTI Regulation

The skin acts as a mechanical barrier that protects the body from the exterior environment, and skin barrier function is attributed to the stratum corneum (SC), which is composed of keratinocytes and skin lipids. Skin barrier homeostasis is maintained by a delicate balance between the differentiation and exfoliation of keratinocytes, and keratinocyte desquamation is regulated by members of the serine protease kalikrein (KLK) family and their endogenous inhibitor SPINK5/LEKTI (serine protease inhibitor Kazal type 5/lympho-epithelial Kazal-type-related inhibitor). Furthermore, SPINK5/LEKTI deficiency is involved in impaired skin barrier function caused by KLK over-activation. We sought to determine whether increased SPINK5/LEKTI expression ameliorates atopic dermatitis (AD) by strengthening skin barrier function using the ethanol extract of Lobelia chinensis (LCE) and its active compound, diosmetin, by treating human keratinocytes with UVB and using a DNCB-induced murine model of atopic dermatitis. LCE or diosmetin dose-dependently increased the transcriptional activation of SPINK5 promoter and prevented DNCB-induced skin barrier damage by modulating events downstream of SPINK5, that is, KLK, PAR2 (protease activated receptor 2), and TSLP (thymic stromal lymphopoietin). LCE or diosmetin normalized immune response in DNCB treated SKH-1 hairless mice as determined by reductions in serum immunoglobulin E and interleukin-4 levels and numbers of lesion-infiltrating mast cells. Our results suggest that LCE and diosmetin are good candidates for the treatment of skin barrier-disrupting diseases such as Netherton syndrome or AD, and that they do so by regulating SPINK5/LEKTI.

Metformin inhibits melanoma cell metastasis by suppressing the miR-5100/SPINK5/STAT3 axis

Melanoma is the most lethal skin cancer characterized by its high metastatic potential. It is urgent to find novel therapy strategies to overcome this feature. Metformin has been confirmed to suppress invasion and migration of various types of cancer. However, additional mechanisms underlying the antimetastatic effect of metformin on melanoma require further investigation. Here, we performed microarray analysis and uncovered an altered mRNA and miRNA expression profile between melanoma and nevus. Luciferase reporter assay confirmed that miR-5100 targets SPINK5 to activate STAT3 phosphorylation. Migration and wound healing assays showed that the miR-5100/SPINK5/STAT3 axis promotes melanoma cell metastasis; the mechanism was proven by initiation of epithelial–mesenchymal transition. Co-immunoprecipitation (Co-IP) further confirmed an indirect interaction between SPINK5 and STAT3. Furthermore, metformin dramatically inhibited miR-5100/SPINK5/STAT3 pathway, and decreased B16-F10 cell metastasis to lung in C57 mouse module. Intriguingly, pretreatment of metformin before melanoma cell injection improved this effect further. These findings exposed the underlying mechanisms of action of metformin and update the use of this drug to prevent metastasis in melanoma.

Oral supplementation of sea cucumber and its hydrolysate mitigates ultraviolet A-induced photoaging in hairless mice

BACKGROUND

Chronic exposure to ultraviolet (UV) radiation promotes skin photoaging, which is clinically characterized by dryness, laxity, and wrinkling. Sea cucumber (Stichopus japonicus) (SC) is a marine organism with culinary and medicinal applications, especially in Asian countries. It is also a potential nutraceutical as it exhibits bioactive effects, such as antioxidant, antitumor, and anticancer activity. This study examined the effects of SC and its hydrolysate (SCH) on ultraviolet A (UVA) induced skin barrier function and wrinkle formation using hairless mice.

RESULTS

Ultraviolet A significantly induced transepidermal water loss and wrinkle formation, which were significantly mitigated upon oral administration of SC and SCH. Sea cucumber also mitigated the UVA-induced downregulation of epidermal natural moisturizing factors and the upregulation of Aqp3, Mmp13, Tnfa, and Il6 mRNA levels in the mouse skin.

CONCLUSION

Taken together, these results suggest that dietary SC and SCH exert anti-photoaging effects by modulating filaggrin synthesis and desquamation in the epidermis and regulating the NF-κB pathway in the skin. Our research indicates that SC and SCH have potential applications in nutricosmetics for photoaging. © 2021 Society of Chemical Industry.

SPINKs in Tumors: Potential Therapeutic Targets

The serine protease inhibitor Kazal type (SPINK) family includes SPINK1-14 and is the largest branch in the serine protease inhibitor family. SPINKs play an important role in pancreatic physiology and disease, sperm maturation and capacitation, Nager syndrome, inflammation and the skin barrier. Evidence shows that the unregulated expression of SPINK1, 2, 4, 5, 6, 7, and 13 is closely related to human tumors. Different SPINKs exhibit various regulatory modes in different tumors and can be used as tumor prognostic markers. This article reviews the role of SPINK1, 2, 4, 5, 6, 7, and 13 in different human cancer processes and helps to identify new cancer treatment targets.

Netherton syndrome plus atopic dermatitis: Two new genetic mutations in the same patient

A child who comes to our attention for the appearance of erythematous, scaly lesions localized to the upper and lower limbs for 2 months. Histological features suggested ichthyosiform disease and concomitant mutations in the SPINK5 and FLG2 genes confirmed Netherton syndrome with severe atopic manifestations.

Generation of a quenched phosphonate activity-based probe for labelling the active KLK7 protease

Kallikrein 7 (KLK7) is a chymotrypsin-like serine protease with established roles in skin diseases like the rare Netherton syndrome, an overdesquamating and inflammatory condition, but also common atopic dermatitis, and a potential drug target for these and possibly other diseases. Nevertheless, tools to determine the active KLK7 enzyme are not available. Here, a mixed alkyl aryl phosphonate quenched activity-based probe that detects the active KLK7 was developed and evaluated in vitro. This KLK7-qABP can potentially be used to monitor KLK7 activity in vivo.

Netherton Syndrome in Children: Management and Future Perspectives

Netherton syndrome (NS) is a genetic, multisystemic disease classically distinguished by a triad of clinical manifestations: congenital ichthyosiform erythroderma, hair shaft abnormalities, and immune dysregulation. Due to the complex pathogenesis of the disease, there are no specific therapies currently accessible for patients with NS. An early diagnosis is crucial to start the correct management of these patients. A multidisciplinary approach, including specialists in immunology, allergology, and dermatology, is necessary to set up the best therapeutic pathway. We conducted a review with the aim to summarize the different therapeutic strategies currently accessible and potentially available in the future for children with NS. However, given the limited data in the literature, the best-tailored management should be decided upon the basis of the specific clinical characteristics of the patients with this rare clinical condition. Further comprehension of the pathophysiology of the disease could lead to more efficacious specific therapeutic options, which could allow a change in the natural history of NS.

A novel SPINK5 donor splice site variant in a child with Netherton syndrome

BACKGROUND

Netherton syndrome (NS) is a genodermatosis caused by loss-of-function mutations in SPINK5, resulting in aberrant LEKTI expression.

METHOD

Next-generation sequencing of SPINK5 (NM_001127698.1) was carried out and functional studies were performed by immunofluorescence microscopy of a lesional skin biopsy using anti-LEKTI antibodies.

RESULTS

We describe a novel SPINK5 likely pathogenic donor splice site variant (NM_001127698.1:c.2015+5G>A) in a patient with NS and confirm its functional significance by demonstrating complete loss of LEKTI expression in lesional skin by immunofluorescence analysis.

CONCLUSION

The 2015+5G>A is a novel, likely pathogenic variant in NS. Herein we review and assimilate documented SPINK5 pathogenic variants and discuss possible genotype-phenotype associations in NS.

Coptis chinensis Franch Directly Inhibits Proteolytic Activation of Kallikrein 5 and Cathelicidin Associated with Rosacea in Epidermal Keratinocytes

Rosacea is a common and chronic inflammatory skin disease that is characterized by dysfunction of the immune and vascular system. The excessive production and activation of kallikerin 5 (KLK5) and cathelicidin have been implicated in the pathogenesis of rosacea. Coptis chinensis Franch (CC) has been used as a medicinal herb in traditional oriental medicine. However, little is known about the efficacy and mechanism of action of CC in rosacea. In this study, we evaluate the effect of CC and its molecular mechanism on rosacea in human epidermal keratinocytes. CC has the capacity to downregulate the expression of KLK5 and cathelicidin, and also inhibits KLK5 protease activity, which leads to reduced processing of inactive cathelicidin into active LL-37. It was determined that CC ameliorates the expression of pro-inflammatory cytokines through the inhibition of LL-37 processing. In addition, it was confirmed that chitin, an exoskeleton of Demodex mites, mediates an immune response through TLR2 activation, and CC inhibits TLR2 expression and downstream signal transduction. Furthermore, CC was shown to inhibit the proliferation of human microvascular endothelial cells induced by LL-37, the cause of erythematous rosacea. These results demonstrate that CC improved rosacea by regulating the immune response and angiogenesis, and revealed its mechanism of action, indicating that CC may be a useful therapeutic agent for rosacea.

Compound K improves skin barrier function by increasing SPINK5 expression

Background

The skin acts as a barrier to protect organisms against harmful exogenous agents. Compound K (CK) is an active metabolite of ginsenoside Rb1, Rb2 and Rc, and researchers have focused on its skin protective efficacy. In this study, we hypothesized that increased expression of the serine protease inhibitor Kazal type-5 (SPINK5) may improve skin barrier function.

Methods

We screened several ginsenosides to increase SPINK5 gene promoter activity using a transactivation assay and found that CK can increase SPINK5 expression. To investigate the protective effect of CK on the skin barrier, RT-PCR and Western blotting were performed to investigate the expression levels of SPINK5, kallikrein 5 (KLK5), KLK7 and PAR2 in UVB-irradiated HaCaT cells. Measurement of transepidermal water loss (TEWL) and histological changes associated with the skin barrier were performed in a UVB-irradiated mouse model and a 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis-like model.

Results

CK treatment increased the expression of SPINK5 and decreased the expression of its downstream genes, such as KLKs and PAR2. In the UVB-irradiated mouse model and the DNCB-induced atopic dermatitis model, CK restored increased TEWL and decreased hydration and epidermal hyperplasia. In addition, CK normalized the reduced SPINK5 expression caused by UVB or DNCB, thereby restoring the expression of the proteins involved in desquamation to a level similar to normal.

Conclusions

Our data showed that CK contributes to improving skin-barrier function in UVB-irradiated and DNCB-induced atopic dermatitis-like models through SPINK5. These results suggest that therapeutic attempts with CK might be useful in treating barrier-disrupted diseases.

Unraveling the molecular pathobiology of vocal fold systemic dehydration using an in vivo rabbit model

Vocal folds are a viscoelastic multilayered structure responsible for voice production. Vocal fold epithelial damage may weaken the protection of deeper layers of lamina propria and thyroarytenoid muscle and impair voice production. Systemic dehydration can adversely affect vocal function by creating suboptimal biomechanical conditions for vocal fold vibration. However, the molecular pathobiology of systemically dehydrated vocal folds is poorly understood. We used an in vivo rabbit model to investigate the complete gene expression profile of systemically dehydrated vocal folds. The RNA-Seq based transcriptome revealed 203 differentially expressed (DE) vocal fold genes due to systemic dehydration. Interestingly, function enrichment analysis showed downregulation of genes involved in cell adhesion, cell junction, inflammation, and upregulation of genes involved in cell proliferation. RT-qPCR validation was performed for a subset of DE genes and confirmed the downregulation of DSG1, CDH3, NECTIN1, SDC1, S100A9, SPINK5, ECM1, IL1A, and IL36A genes. In addition, the upregulation of the transcription factor NR4A3 gene involved in epithelial cell proliferation was validated. Taken together, these results suggest an alteration of the vocal fold epithelial barrier independent of inflammation, which could indicate a disruption and remodeling of the epithelial barrier integrity. This transcriptome provides a first global picture of the molecular changes in vocal fold tissue in response to systemic dehydration. The alterations observed at the transcriptional level help to understand the pathobiology of dehydration in voice function and highlight the benefits of hydration in voice therapy.

The role of kallikreins in inflammatory skin disorders and their potential as therapeutic targets

The skin is a vital organ of the human body, serving numerous protective and functional roles that are essential for survival. Residing in the epidermis are various epidermal proteases responsible for the establishment and regulation of barrier function. The human tissue kallikrein-related peptidase family conserves homeostasis of the skin barrier through their roles in desquamation, antimicrobial defense, innate immune response, and barrier maintenance. The activity of kallikreins is tightly regulated and dysregulation of kallikrein activity is seen to contribute to the formation of several inflammatory skin disorders. This review highlights the roles of kallikreins in skin homeostasis and pathologies. Due to their part in these skin disorders, inhibitors of the skin kallikreins have become attractive therapeutics. Over the past few years, both natural and synthetic inhibitors of several kallikreins have been identified and are undergoing further development as treatments to restore compromised barrier function. This review summarizes the kallikrein inhibitors under development for this purpose. These inhibitors remain promising therapeutics in cases of severe skin inflammation not well managed by current therapies.

Genetic activation of Nrf2 reduces cutaneous symptoms in a murine model of Netherton syndrome

Netherton syndrome is a monogenic autosomal recessive disorder primarily characterized by the detachment of the uppermost layer of the epidermis, the stratum corneum It results from mutations in the SPINK5 gene, which codes for a kallikrein inhibitor. Uncontrolled kallikrein activity leads to premature desquamation, resulting in a severe epidermal barrier defect and subsequent life-threatening systemic infections and chronic cutaneous inflammation. Here, we show that genetic activation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nfe2l2/Nrf2) in keratinocytes of Spink5 knockout mice, a model for Netherton syndrome, significantly alleviates their cutaneous phenotype. Nrf2 activation promoted attachment of the stratum corneum and concomitant epidermal barrier function, and reduced the expression of pro-inflammatory cytokines such as tumor necrosis factor α and thymic stromal lymphopoietin. Mechanistically, we show that Nrf2 activation induces overexpression of secretory leukocyte protease inhibitor (Slpi), a known inhibitor of kallikrein 7 and elastase 2, in mouse and human keratinocytes in vivo and in vitro, respectively. In the Spink5-deficient epidermis, the upregulation of Slpi is likely to promote stabilization of corneodesmosomes, thereby preventing premature desquamation. Our results suggest pharmacological NRF2 activation as a promising treatment modality for Netherton syndrome patients.This article has an associated First Person interview with the first author of the paper.

The matriptase-prostasin proteolytic cascade in dermatologic diseases

The proper development and function of skin and hair are dependent on proteolytic activities. Specifically, the matriptase-prostasin cascade is a series of proteolytic reactions in the epidermis integral to normal regulation of desquamation. An increasing amount of research describing this pathway has recently become available, and the importance of this pathway is exhibited by the association of genetic defects in this pathway with human diseases of the skin and hair. Given the relevance of this pathway to dermatology, we provide a review of the current understanding of its relevance to distinct clinical entities, including ichthyosis-hypotrichosis and Netherton syndromes.

The antimicrobial peptide derived from insulin-like growth factor-binding protein 5, AMP-IBP5, regulates keratinocyte functions through Mas-related gene X receptors

BACKGROUND

In addition to their microbicidal properties, host defense peptides (HDPs) display various immunomodulatory functions, including keratinocyte production of cytokines/chemokines, proliferation, migration and wound healing. Recently, a novel HDP named AMP-IBP5 (antimicrobial peptide derived from insulin-like growth factor-binding protein 5) was shown to exhibit antimicrobial activity against numerous pathogens, even at concentrations comparable to those of human β-defensins and LL-37. However, the immunomodulatory role of AMP-IBP5 in cutaneous tissue remains unknown.

OBJECTIVES

To investigate whether AMP-IBP5 triggers keratinocyte activation and to clarify its mechanism.

METHODS

Production of cytokines/chemokines and growth factors was determined by appropriate ELISA kits. Cell migration was assessed by in vitro wound closure assay, whereas cell proliferation was analyzed using BrdU incorporation assay complimented with XTT assay. MAPK and NF-κB activation was determined by Western blotting. Intracellular cAMP levels were assessed using cAMP enzyme immunoassay kit.

RESULTS

Among various cytokines/chemokines and growth factors tested, AMP-IBP5 selectively increased the production of IL-8 and VEGF. Moreover, AMP-IBP5 markedly enhanced keratinocyte migration and proliferation. AMP-IBP5-induced keratinocyte activation was mediated by Mrg X1-X4 receptors with MAPK and NF-κB pathways working downstream, as evidenced by the inhibitory effects of MrgX1-X4 siRNAs and ERK-, JNK-, p38- and NF-κB-specific inhibitors. We confirmed that AMP-IBP5 indeed induced MAPK and NF-κB activation. Furthermore, AMP-IBP5-induced VEGF but not IL-8 production correlated with an increase in intracellular cAMP.

CONCLUSIONS

Our findings suggest that in addition to its antimicrobial function, AMP-IBP5 might contribute to wound healing process through activation of keratinocytes.

KLK5 and KLK7 Ablation Fully Rescues Lethality of Netherton Syndrome-Like Phenotype

Netherton syndrome (NS) is a severe skin disease caused by the loss of protease inhibitor LEKTI, which leads to the dysregulation of epidermal proteases and severe skin-barrier defects. KLK5 was proposed as a major protease in NS pathology, however its inactivation is not sufficient to rescue the lethal phenotype of LEKTI-deficient mice. In this study, we further elucidated the in vivo roles of the epidermal proteases in NS using a set of mouse models individually or simultaneously deficient for KLK5 and KLK7 on the genetic background of a novel NS-mouse model. We show that although the ablation of KLK5 or KLK7 is not sufficient to rescue the lethal effect of LEKTI-deficiency simultaneous deficiency of both KLKs completely rescues the epidermal barrier and the postnatal lethality allowing mice to reach adulthood with fully functional skin and normal hair growth. We report that not only KLK5 but also KLK7 plays an important role in the inflammation and defective differentiation in NS and KLK7 activity is not solely dependent on activation by KLK5. Altogether, these findings show that unregulated activities of KLK5 and KLK7 are responsible for NS development and both proteases should become targets for NS therapy.

Kallikrein-related peptidases (KLKs) as emerging therapeutic targets: focus on prostate cancer and skin pathologies

INTRODUCTION

Tissue kallikrein and the kallikrein-related peptidases (KLKs) constitute a family of 15 homologous secreted serine proteases with trypsin- or chymotrypsin-like activities, which participate in a broad spectrum of physiological procedures. Deregulated expression and/or activation of the majority of the family members have been reported in several human diseases, thereby making KLKs ideal targets for therapeutic intervention.

AREAS COVERED

In the present review, we summarize the role of KLKs in normal human physiology and pathology, focusing on prostate cancer and skin diseases. Furthermore, we discuss the recent advances in the development of KLK-based therapies. A great number of diverse engineered KLKs inhibitors with improved potency, selectivity and immunogenicity have been synthesized by redesigning examples that are endogenous and naturally occurring. Moreover, encouraging results have been documented using KLKs-based vaccines and immunotherapies, as well as KLKs-mediated activation of pro-drugs. Finally, KLKs-targeting aptamers and KLKs-based imaging tools represent novel approaches towards the exploitation of KLKs' therapeutic value.

EXPERT OPINION

The central/critical roles of KLK family in several human pathologies highlight KLKs as attractive molecular targets for developing novel therapeutics.

A Comprehensive Review of the Cosmeceutical Benefits of Vanda Species (Orchidaceae)

Orchidaceae is the largest family of flowering plants with over 35000 species and 850 genera. About 3300 species of orchids are found in Malaysia and the diversity is highest in the Main, Keledang, Bintang and Tahan Ranges. Apart from being prized for their beauty, orchids have long been used by humans for medicinal purposes. Today the uses of orchids have been expanded to the food and cosmetics industries. Many cosmeceutical companies use orchid extracts as an active ingredient in their products. Previous studies provide riveting insights into the potential uses of orchid extracts as an active agent in cosmetics. This paper describes the cosmeceutical potential of orchids as an anti-aging, and skin moisturizing agent. Orchid extracts from Vanda coerulea and V. teres delay aging caused by reactive oxygen species (ROS) following UV irradiation through their antioxidant and anti-inflammatory activity. These extracts also show anti-aging properties by stimulating cytochrome c oxidase (complex IV), which is part of the electron transport chain in mitochondria. Stimulation of cytochrome c oxidase improves the respiratory function of mitochondria in keratinocytes. The presence of mucilage in orchids enables them to maintain skin hydration. Mucilage functions as a moisturizer and emollient due to its high water binding capacity. Additionally, orchid extracts provide skin hydration by stimulating aquaporin 3 (AQP3) and LEKTI protein expression. The presence of AQP3 leads to a five-fold increase in water permeability, which subsequently increases stratum corneum hydration. Increased LEKTI protein expression mediated by orchid extracts reduces the degradation of desmoglein-1 and enhances the structural function of desmosomes, which play important roles in preventing water evaporation.

Gene expression profiling in pachyonychia congenita skin

BACKGROUND

Pachyonychia congenita (PC) is a skin disorder resulting from mutations in keratin (K) proteins including K6a, K6b, K16, and K17. One of the major symptoms is painful plantar keratoderma. The pathogenic sequelae resulting from the keratin mutations remain unclear.

OBJECTIVE

To better understand PC pathogenesis.

METHODS

RNA profiling was performed on biopsies taken from PC-involved and uninvolved plantar skin of seven genotyped PC patients (two K6a, one K6b, three K16, and one K17) as well as from control volunteers. Protein profiling was generated from tape-stripping samples.

RESULTS

A comparison of PC-involved skin biopsies to adjacent uninvolved plantar skin identified 112 differentially-expressed mRNAs common to patient groups harboring K6 (i.e., both K6a and K6b) and K16 mutations. Among these mRNAs, 25 encode structural proteins including keratins, small proline-rich and late cornified envelope proteins, 20 are related to metabolism and 16 encode proteases, peptidases, and their inhibitors including kallikrein-related peptidases (KLKs), and serine protease inhibitors (SERPINs). mRNAs were also identified to be differentially expressed only in K6 (81) or K16 (141) patient samples. Furthermore, 13 mRNAs were identified that may be involved in pain including nociception and neuropathy. Protein profiling, comparing three K6a plantar tape-stripping samples to non-PC controls, showed changes in the PC corneocytes similar, but not identical, to the mRNA analysis.

CONCLUSION

Many differentially-expressed genes identified in PC-involved skin encode components critical for skin barrier homeostasis including keratinocyte proliferation, differentiation, cornification, and desquamation. The profiling data provide a foundation for unraveling the pathogenesis of PC and identifying targets for developing effective PC therapeutics.

Regulation of serine protease inhibitor Kazal type-5 (SPINK5) gene expression in the keratinocytes

Objectives

Serine protease inhibitor Kazal type-5 (SPINK5) plays a crucial role in deciding the timing of desquamation of the skin. Its gene expression is limited at the very surface of the stratum granulosum (SG), whereas expression of kallikreins (KLKs) encoding proteases is usually found throughout the stratum spinosum and SG.

Methods

To explore the difference in expression regulation of these proteases/inhibitors, the function of SPINK5 promoter was examined using luciferase assay.

Results

Luciferase assay targeting the SPINK5 promoters (nucleotide −676/−532 and −318/−146 from the major transcription start site) showed high intensity in NHEK human keratinocyte. These two sites had neither common cis-elements nor GATA3 element but electrophoretic mobility shift assay showed similar retardation bands. Moreover, DNA footprinting did not display specific protected bands. Thus, we could not identify cis-element(s) that controlled these elements. Differentiation induced by high Ca²⁺ medium failed to alter their luciferase activities. Transfection of GATA3 expressing vector significantly but slightly increased them and that of vector expressing its dominant negative form decreased.

Conclusions

Although GATA3 is reportedly important for inhibition of proliferation and induction of differentiation of keratinocytes, its effect on SPINK5 expression was indirect and GATA3 alone was insufficient for final differentiation of keratinocytes where full SPINK5 expression was observed.

Netherton's syndrome and lepromatous leprosy: a mere coincidence?

OBJECTIVES

Netherton's syndrome (NS) is a rare autosomal recessive condition, first described in 1958, which involves a complex immunological dysfunction, ichthyosiform dermatitis, and erythroderma, characteristic defects of the hair shaft and atopy. Recurrent bacterial infection in the skin of patients with NS is frequent.

METHODS

This paper represents the first case report of leprosy and concurrent NS.

DISCUSSION

This case merits discussion among doctors in endemic and non-endemic areas to evaluate the chronic use of systemic corticosteroids as a risk factor for leprosy. The present patient came from an endemic area of leprosy and was treated chronically with systemic corticosteroids for erythroderma. This treatment, along with the immunodeficiency related to the syndrome and caused by a genetic mutation in SPINK5, may be a facilitating factor for the infection.

Isomannide derivatives as new class of inhibitors for human kallikrein 7

Human kallikrein 7 (KLK7) is a potential target for the treatment of skin inflammation and cancer. Despite its potential, few KLK7-specific small-molecule inhibitors have been reported in the literature. As an extension of our program to design serine protease inhibitors, here we describe the in vitro assays and the investigation of the binding mechanism by molecular dynamics simulation of a novel class of pseudo-peptide inhibitors derived from isomannide. Of the inhibitors tested, two inhibited KLK7 with K(i) values in the low micromolar range (9g=1.8μM; 9j=3.0μM). Eadie-Hofstee and Dixon plots were used to evaluate the competitive mechanism of inhibition for the molecules. Calculated binding free energies using molecular MM/PB(GB)SA approach are in good agreement with experimental results, suggesting that the inhibitors share the same binding mode, which is stabilized by hydrophobic interactions and by a conserved network of hydrogen bonds. The promising results obtained in this study make these compounds valid leads for further optimization studies aiming to improve the potency of this new class of kallikrein inhibitors.

Netherton syndrome in one Chinese adult with a novel mutation in the SPINK5 gene and immunohistochemical studies of LEKTI

BACKGROUND

Netherton syndrome (NS) is a severe autosomal recessive ichthyosis. It is characterized by congenital ichthyosiform erythroderma, trichorrhexis invaginata, ichthyosis linearis circumflexa, atopic diathesis, and frequent bacterial infections. The disease is caused by mutations in the SPINK5 (serine protease inhibitor Kazal-type 5) gene, a new type of serine protease inhibitor involved in the regulation of skin barrier formation and immunity. We report one Chinese adult with NS. The patient had typical manifestation of NS except for trichorrhexis invaginata with an atopic diathesis and recurrent staphylococcal infections since birth.

AIMS

To evaluate the gene mutation and of its product activity of SPINK5 gene in confirmation of the diagnosis of one Chinese adult with NS.

MATERIALS AND METHODS

To screen mutations in the SPINK5 gene, 33 exons and flanking intron boundaries of SPINK5 were amplified with polymerase chain reaction (PCR) and used for direct sequencing. In addition, immunohistochemical staining of LEKTI (lymphoepithelial Kazal-type-related inhibitor) with specific antibody was used to confirm the diagnosis of NS. The results were compared with that of healthy individuals (twenty-five blood samples).

RESULTS

A G318A mutation was found at exon 5 of patient's SPINK5 gene which is a novel missense mutation. The PCR amplification products with mutation-specific primer were obtained only from the DNA of the patients and their mother, but not from their father and 25 healthy individuals. Immunohistochemical studies indicated there was no LEKTI expression in NS patient's skin and there was a strong LEKTI expression in the normal human skin.

CONCLUSION

In this report, we describe heterozygous mutation in the SPINK5 gene and expression of LEKTI in one Chinese with NS. The results indicate that defective expression of LEKTI in the epidermis and mutations of SPINK5 gene are reliable for diagnostic feature of NS with atypical clinical symptoms.

Membrane-anchored serine proteases in vertebrate cell and developmental biology

Analysis of vertebrate genome sequences at the turn of the millennium revealed that a vastly larger repertoire of enzymes execute proteolytic cleavage reactions within the pericellular and extracellular environments than was anticipated from biochemical and molecular analysis. Most unexpected was the unveiling of an entire new family of structurally unique multidomain serine proteases that are anchored directly to the plasma membrane. Unlike secreted serine proteases, which function primarily in tissue repair, immunity, and nutrient uptake, these membrane-anchored serine proteases regulate fundamental cellular and developmental processes, including tissue morphogenesis, epithelial barrier function, ion and water transport, cellular iron export, and fertilization. Here the cellular and developmental biology of this fascinating new group of proteases is reviewed. Particularly highlighted is how the study of membrane-anchored serine proteases has expanded our knowledge of the range of physiological processes that require regulated proteolysis at the cell surface.

Association of SPINK5 gene polymorphisms with atopic dermatitis in Northeast China

BACKGROUND

Defect in the SPINK5 gene is known to be implicated in Netherton syndrome (NS), and has been suggested to be a locus predisposing to atopy in general. Coding polymorphisms in SPINK5 exons 13, 14 and 26 have been reported to be associated with atopic dermatitis (AD), asthma and high level of IgE.

OBJECTIVES

To examine whether the SPINK5 gene polymorphisms are associated with AD in Northeast China, and to assess how variants influence selected phenotypic traits.

METHODS

A case-control study was conducted on four non-synonymous polymorphisms in the coding region of SPINK5 in AD and controls. The SPINK5 gene polymorphisms were analyzed using the PCR and RFLP methods.

RESULTS

For the four non-synonymous SNPs, A1103G(Asn368Ser), G1156A(Asp386Asn), G1258A(Glu420Lys), G2475T(Glu825Asp) in SPINK5, the allelic frequencies in the AD cohort were 0.55 for 1103G, 0.57 for 1156A, 0.54for 1258A, 0.62 for 2475T, consistent with those already published in the original British and Japanese cohorts. The T allele of SNP 2475G > T was found to be significantly associated with AD. There were significant differences in genotype frequencies for G1258A(Glu420Lys) and G2475T(Glu825Asp) but not for A1103G(Asn368Ser) and G1156A(Asp386Asn). Genotypes GA(420Glu/Lys), TT (2475Asp/Asp) and GT(2475Glu/Asp) were significantly more frequent in AD. However, the SPINK5 gene polymorphisms was found not to be associated with AD in regard to either serum IgE levels, concurrent allergic asthma or early onset of AD.

CONCLUSIONS

Our study confirms the association between SPINK5 and AD.

Hint for association of single nucleotide polymorphisms and haplotype in SPINK5 gene with atopic dermatitis in Koreans

Clinical studies, including twin studies, support the concept that the risk of atopic dermatitis (AD) may be mediated through skin-specific genes, rather than simply through systemic immune or atopy risk genes. The SPINK5 gene is expressed on epithelial surfaces and may provide protection against other allergenic serine proteases. Mutations in the SPINK5 gene result in Netherton syndrome, a disorder characterised by AD, ichthyosis, and elevated serum IgE levels. We genotyped 21 single nucleotide polymorphisms (SNPs) from the SPINK5 gene for 1090 case-control samples (631 patients with AD and 459 normal controls) and analysed the SNPs and haplotypes in this gene and also searched for gene-gene interactions between SPINK5 and the DEFB1 gene that we previously reported. Six SNPs [rs17718511 (P = 0.026), rs17860502 (P = 0.024), KN0001820 (P = 0.045), rs60978485 (P = 0.007), rs17718737 (P = 0.02), and rs1422985 (P = 0.038)] and the haplotype TAA (rs60978485, rs6892205, rs2303064; P = 0.023) in the SPINK5 gene showed significant different allelic or genotypic distributions between the AD group and the control group. We also found that four SNPs [rs17718511 (P = 0.033), rs17860502 (P = 0.031), rs60978485 (P = 0.005), rs17718737 (P = 0.023)] and the haplotype TAA (P = 0.02) in the SPINK5 gene showed associations with the susceptibility of the allergic type of AD (ADe). In addition to this finding, we speculate that the SNPs from DEFB1 and SPINK5 affect the individual susceptibility to development of ADe in an additive manner. This study provides evidence for a significant interaction between allergens and the SPINK5 gene that may contribute to ADe susceptibility.