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Alain Hovnanian - One of the best experts on this subject based on the ideXlab platform.
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klk5 inactivation reverses cutaneous hallmarks of Netherton Syndrome
PLOS Genetics, 2015Co-Authors: Laetitia Furio, Georgios Pampalakis, Iacovos P. Michael, Andras Nagy, Georgia Sotiropoulou, Alain HovnanianAbstract:Netherton Syndrome (NS) is a rare and severe autosomal recessive skin disease which can be life-threatening in infants. The disease is characterized by extensive skin desquamation, inflammation, allergic manifestations and hair shaft defects. NS is caused by loss-of-function mutations in SPINK5 encoding the LEKTI serine protease inhibitor. LEKTI deficiency results in unopposed activities of kallikrein-related peptidases (KLKs) and aberrantly increased proteolysis in the epidermis. Spink5⁻/⁻ mice recapitulate the NS phenotype, display enhanced epidermal Klk5 and Klk7 protease activities and die within a few hours after birth because of a severe skin barrier defect. However the contribution of these various proteases in the physiopathology remains to be determined. In this study, we developed a new murine model in which Klk5 and Spink5 were both knocked out to assess whether Klk5 deletion is sufficient to reverse the NS phenotype in Spink5⁻/⁻ mice. By repeated intercrossing between Klk5⁻/⁻ mice with Spink5⁻/⁻ mice, we generated Spink5⁻/⁻Klk5⁻/⁻ animals. We showed that Klk5 knock-out in Lekti-deficient newborn mice rescues neonatal lethality, reverses the severe skin barrier defect, restores epidermal structure and prevents skin inflammation. Specifically, using in situ zymography and specific protease substrates, we showed that Klk5 knockout reduced epidermal proteolytic activity, particularly its downstream targets proteases KLK7, KLK14 and ELA2. By immunostaining, western blot, histology and electron microscopy analyses, we provide evidence that desmosomes and corneodesmosomes remain intact and that epidermal differentiation is restored in Spink5⁻/⁻Klk5⁻/⁻. Quantitative RT-PCR analyses and immunostainings revealed absence of inflammation and allergy in Spink5⁻/⁻Klk5⁻/⁻ skin. Notably, Il-1β, Il17A and Tslp levels were normalized. Our results provide in vivo evidence that KLK5 knockout is sufficient to reverse NS-like symptoms manifested in Spink5⁻/⁻ skin. These findings illustrate the crucial role of protease regulation in skin homeostasis and inflammation, and establish KLK5 inhibition as a major therapeutic target for NS.
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Netherton Syndrome defective kallikrein inhibition in the skin leads to skin inflammation and allergy
Biological Chemistry, 2014Co-Authors: Laetitia Furio, Alain HovnanianAbstract:Netherton Syndrome (NS) is an orphan genetic skin disease with a profound skin barrier defect and severe allergic manifestations. NS is caused by loss of function mutations in SPINK5 encoding lympho-epithelial Kazal-type inhibitor (LEKTI), a secreted multi-domain serine protease inhibitor expressed in stratified epithelia. Studies in mouse models and in NS patients have established that unopposed kallikrein 5 activity triggers stratum corneum detachment and activates PAR-2 signaling, leading to the autonomous production of pro-allergic and pro-inflammatory mediators. This emerging knowledge on NS pathogenesis has highlighted a central role for protease regulation in skin homeostasis but also in the complexity of the disease, and holds the promise of new specific treatments.
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intercellular skin barrier lipid composition and organization in Netherton Syndrome patients
Journal of Investigative Dermatology, 2014Co-Authors: Jeroen Van Smeden, Alain Hovnanian, Laetitia Furio, Michelle Janssens, Walter Boiten, Vincent Van Drongelen, Rob J VreekenAbstract:Netherton Syndrome (NTS) is a rare genetic skin disease caused by mutations in the serine protease inhibitor Kazal-type 5 gene, which encodes the lympho-epithelial Kazal-type–related inhibitor. NTS patients have profoundly impaired skin barrier function. As stratum corneum (SC) lipids have a crucial role in the skin barrier function, we investigated the SC lipid composition and organization in NTS patients. We studied the SC lipid composition by means of mass spectrometry, and the lipid organization was examined by infrared spectroscopy and X-ray diffraction. Decreased free fatty acid (FFA) chain length and increased levels of monounsaturated FFAs were observed in the SC of NTS patients compared with controls. Furthermore, the level of short-chain ceramides (CERs) was enhanced in NTS patients and a strong reduction in long-chain CER levels was seen in several patients. The changes in lipid composition modified the lipid organization leading to an increased disordering of the lipids compared with the controls. In addition, in a subgroup of patients the organization of the lipid layers changed dramatically. The altered FFA and CER profiles in NTS patients corresponded to changes in the expression of enzymes involved in SC lipid processing. The observed changes in lipid composition, lipid organization, and enzyme expression are likely to contribute to the barrier dysfunction in NTS.
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Netherton Syndrome and its multifaceted defective protein lekti
Giornale italiano di dermatologia e venereologia : organo ufficiale Società italiana di dermatologia e sifilografia, 2013Co-Authors: Marina Dalessio, Paola Fortugno, Giovanna Zambruno, Alain HovnanianAbstract:Netherton Syndrome (NS, OMIM 256500) is a rare autosomal recessive disorder manifesting with congenital ichthyosis, a specific hair shaft abnormality named trichorrhexis invaginata, and atopic manifestations. Because of severe complications frequently occurring in the neonatal period, NS prognosis can be poor in infancy. NS is due to loss-of-function mutations in the SPINK5 gene and to the consequent lack of expression of its encoded protein LEKTI in the skin and all stratified epithelial tissues. Following the identification of the NS causative gene and protein, specific diagnostic tools have been developed, thus breaking up the challenge of distinguishing NS from other congenital ichthyoses with overlapping features, and from severe, early-onset forms of atopic dermatitis or psoriasis. Intensive efforts to extend the knowledge into the pathomechanisms of NS have also been made. However, NS management is still problematic due to the lack of specific treatment and unmet needs. This overview summarizes the current state of the art in NS research with an emphasis on the progress made toward disease-specific innovative therapy development.
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Netherton Syndrome new advances in the clinic disease mechanism and treatment
Expert Review of Dermatology, 2012Co-Authors: Alain HovnanianAbstract:The skin forms a very effective protective barrier against water loss and from the surrounding microflora and allergens. Netherton Syndrome (NS) is a rare genetic skin disease with a profound skin barrier defect and constant and severe allergic manifestations. We previously identified SPINK5 encoding LEKTI as the defective gene in NS. Loss-of-function SPINK5 mutations lead to unopposed KLK5 and KLK7 activity, with a dual consequence on skin homeostasis: the stratum corneum is prematurely detached secondary to the proteolytic cleavage of corneodesmosomal cadherins; in parallel, KLK5 activates PAR2, leading to proinflammatory and proallergic cascades triggering the production of pro-Th2 molecules, such as thymic stromal lymphopoietin. These results have shed light on the importance of protease regulation and signaling in skin homeostasis, inflammation and allergy, and have pointed to new therapeutic targets in NS.
Laetitia Furio - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE KLK5 Inactivation Reverses Cutaneous Hallmarks of Netherton Syndrome
2016Co-Authors: Laetitia Furio, Georgios Pampalakis, Iacovos P. Michael, Andras NagyAbstract:Netherton Syndrome (NS) is a rare and severe autosomal recessive skin disease which can be life-threatening in infants. The disease is characterized by extensive skin desqua-mation, inflammation, allergic manifestations and hair shaft defects. NS is caused by loss-of-function mutations in SPINK5 encoding the LEKTI serine protease inhibitor. LEKTI deficiency results in unopposed activities of kallikrein-related peptidases (KLKs) and aber-rantly increased proteolysis in the epidermis. Spink5-/- mice recapitulate the NS pheno-type, display enhanced epidermal Klk5 and Klk7 protease activities and die within a few hours after birth because of a severe skin barrier defect. However the contribution of these various proteases in the physiopathology remains to be determined. In this study, we developed a new murine model in which Klk5 and Spink5 were both knocked out to assess whether Klk5 deletion is sufficient to reverse the NS phenotype in Spink5-/-mice. By repeated intercrossing between Klk5-/- mice with Spink5-/-mice, we generated Spink5-/-Klk5-/- animals. We showed that Klk5 knock-out in Lekti-deficient newborn mice rescues neonatal lethality, reverses the severe skin barrier defect, restores epiderma
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intrafamily and interfamilial phenotype variation and immature immunity in patients with Netherton Syndrome and finnish spink5 founder mutation
JAMA Dermatology, 2016Co-Authors: Katariina Hannulajouppi, Riitta Marttila, Mirja Tuomiranta, Mette Ilander, Laetitia Furio, Satuleena Laasanen, Leila Jeskanen, Valtteri Hayry, Mervi KanervaAbstract:Importance Netherton Syndrome (NS) is a rare and severe genodermatosis caused by SPINK5 mutations leading to the loss of lymphoepithelial Kazal-type–related inhibitor (LEKTI). Netherton Syndrome is characterized by neonatal scaling erythroderma, a bamboolike hair defect, a substantial skin barrier defect, and a profound atopic diathesis. Netherton Syndrome has been proposed to be a primary immunodeficiency Syndrome because of the high frequency of infections. The precise mechanisms underlying the disease are not fully understood. Objective To study the association of the SPINK5 mutation with the NS phenotype and the extent of immunologic deficiencies in NS. Design, Setting, and Participants Relevant tissue samples and follow-up data from 11 patients with NS from 7 families, including 3 multiplex families, were collected, constituting all known patients with NS in Finland. Another patient with NS from a neighboring country was included. Data were collected from August 10, 2011, to February 20, 2015. SPINK5 mutations were sequenced, and thorough clinical evaluation and histopathologic and immunohistochemical evaluations of skin samples were performed. The function of natural killer cells, lymphocyte phenotype, and serum immunoglobulin subclass levels were evaluated. Data analysis was conducted from October 19, 2011, to February 20, 2015. Main Outcomes and Measures The nature of SPINK5 mutations and their correlation with phenotypes in Finnish patients with NS, intrafamilial phenotype variations, and the type of immunologic defects in NS were evaluated. Results Among the 11 Finnish patients with NS (8 male [73%]; 3 female [27%]; mean [SD] age, 30.1 [9.1] years), a Finnish founder mutation c.652C>T (p.Arg218*) in SPINK5 was identified in 10 patients from 6 families who all originated from the same region. Eight patients were homozygotes for this mutation and 2 siblings were compound heterozygotes with a splice site mutation c.1220 + 1G>C (IVS13 + 1 G>C). Phenotypes were comparable, but some intrafamilial and interfamilial variations were noted. Compound heterozygous patients had a milder phenotype and showed residual LEKTI expression. A previously unreported c.1772delT (p.Leu591Glnfs124*) mutation was found in 1 patient with a phenotype similar to the patients homozygous for the founder mutation. The patient from the neighboring country had a distinct phenotype and different mutations. Immunologically, natural killer cells had an immature phenotype and impaired cytotoxicity and degranulation, levels of memory B cells were reduced, and serum IgG4 levels were elevated. Intravenous immunoglobulin treatment has been beneficial in 1 patient with NS. Conclusions and Relevance This report discloses a prevalent SPINK5 founder mutation in Finland and illustrates NS phenotype variability. Our results also point to a possible role of immature immunity in the frequent infections seen in NS.
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klk5 inactivation reverses cutaneous hallmarks of Netherton Syndrome
PLOS Genetics, 2015Co-Authors: Laetitia Furio, Georgios Pampalakis, Iacovos P. Michael, Andras Nagy, Georgia Sotiropoulou, Alain HovnanianAbstract:Netherton Syndrome (NS) is a rare and severe autosomal recessive skin disease which can be life-threatening in infants. The disease is characterized by extensive skin desquamation, inflammation, allergic manifestations and hair shaft defects. NS is caused by loss-of-function mutations in SPINK5 encoding the LEKTI serine protease inhibitor. LEKTI deficiency results in unopposed activities of kallikrein-related peptidases (KLKs) and aberrantly increased proteolysis in the epidermis. Spink5⁻/⁻ mice recapitulate the NS phenotype, display enhanced epidermal Klk5 and Klk7 protease activities and die within a few hours after birth because of a severe skin barrier defect. However the contribution of these various proteases in the physiopathology remains to be determined. In this study, we developed a new murine model in which Klk5 and Spink5 were both knocked out to assess whether Klk5 deletion is sufficient to reverse the NS phenotype in Spink5⁻/⁻ mice. By repeated intercrossing between Klk5⁻/⁻ mice with Spink5⁻/⁻ mice, we generated Spink5⁻/⁻Klk5⁻/⁻ animals. We showed that Klk5 knock-out in Lekti-deficient newborn mice rescues neonatal lethality, reverses the severe skin barrier defect, restores epidermal structure and prevents skin inflammation. Specifically, using in situ zymography and specific protease substrates, we showed that Klk5 knockout reduced epidermal proteolytic activity, particularly its downstream targets proteases KLK7, KLK14 and ELA2. By immunostaining, western blot, histology and electron microscopy analyses, we provide evidence that desmosomes and corneodesmosomes remain intact and that epidermal differentiation is restored in Spink5⁻/⁻Klk5⁻/⁻. Quantitative RT-PCR analyses and immunostainings revealed absence of inflammation and allergy in Spink5⁻/⁻Klk5⁻/⁻ skin. Notably, Il-1β, Il17A and Tslp levels were normalized. Our results provide in vivo evidence that KLK5 knockout is sufficient to reverse NS-like symptoms manifested in Spink5⁻/⁻ skin. These findings illustrate the crucial role of protease regulation in skin homeostasis and inflammation, and establish KLK5 inhibition as a major therapeutic target for NS.
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Netherton Syndrome defective kallikrein inhibition in the skin leads to skin inflammation and allergy
Biological Chemistry, 2014Co-Authors: Laetitia Furio, Alain HovnanianAbstract:Netherton Syndrome (NS) is an orphan genetic skin disease with a profound skin barrier defect and severe allergic manifestations. NS is caused by loss of function mutations in SPINK5 encoding lympho-epithelial Kazal-type inhibitor (LEKTI), a secreted multi-domain serine protease inhibitor expressed in stratified epithelia. Studies in mouse models and in NS patients have established that unopposed kallikrein 5 activity triggers stratum corneum detachment and activates PAR-2 signaling, leading to the autonomous production of pro-allergic and pro-inflammatory mediators. This emerging knowledge on NS pathogenesis has highlighted a central role for protease regulation in skin homeostasis but also in the complexity of the disease, and holds the promise of new specific treatments.
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intercellular skin barrier lipid composition and organization in Netherton Syndrome patients
Journal of Investigative Dermatology, 2014Co-Authors: Jeroen Van Smeden, Alain Hovnanian, Laetitia Furio, Michelle Janssens, Walter Boiten, Vincent Van Drongelen, Rob J VreekenAbstract:Netherton Syndrome (NTS) is a rare genetic skin disease caused by mutations in the serine protease inhibitor Kazal-type 5 gene, which encodes the lympho-epithelial Kazal-type–related inhibitor. NTS patients have profoundly impaired skin barrier function. As stratum corneum (SC) lipids have a crucial role in the skin barrier function, we investigated the SC lipid composition and organization in NTS patients. We studied the SC lipid composition by means of mass spectrometry, and the lipid organization was examined by infrared spectroscopy and X-ray diffraction. Decreased free fatty acid (FFA) chain length and increased levels of monounsaturated FFAs were observed in the SC of NTS patients compared with controls. Furthermore, the level of short-chain ceramides (CERs) was enhanced in NTS patients and a strong reduction in long-chain CER levels was seen in several patients. The changes in lipid composition modified the lipid organization leading to an increased disordering of the lipids compared with the controls. In addition, in a subgroup of patients the organization of the lipid layers changed dramatically. The altered FFA and CER profiles in NTS patients corresponded to changes in the expression of enzymes involved in SC lipid processing. The observed changes in lipid composition, lipid organization, and enzyme expression are likely to contribute to the barrier dysfunction in NTS.
Georgia Sotiropoulou - One of the best experts on this subject based on the ideXlab platform.
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cathelicidin represents a new target for manipulation of skin inflammation in Netherton Syndrome
Biochimica et Biophysica Acta, 2020Co-Authors: Eleni Zingkou, Georgios Pampalakis, Georgia SotiropoulouAbstract:Abstract Netherton Syndrome (NS) is a severe ichthyosis caused by inactivating mutations in the SPINK5 gene encoding the serine protease inhibitor LEKTI. Spink5−/− mice recapitulate NS and die perinatally from extensive dehydration as a result of a severe defect of the epidermal barrier. We showed that deletion of Klk5 in Spink5−/− rescues neonatal lethality (Furio et al., 2015). However, Spink5−/−Klk5−/− mice developed skin shedding and inflammation during the first week from birth and the majority (70%) succumbed on P7. The remaining mice lived short (i.e. mean survival was 5 months) indicating alternative inflammatory pathways. Since cathelicidin is increased in Spink5−/− epidermis, we investigated whether it could be implicated in NS pathology. Ablation of Camp in Spink5−/− suppressed epidermal inflammation and restored abnormal epidermal differentiation, nevertheless, it failed to inhibit overdesquamation and Spink5−/−Camp−/− succumbed perinatally due to skin barrier defect, similarly to Spink5−/−. Joint invalidation of Klk5 and Camp significantly extended survival of Spink5−/−Klk5−/−Camp−/− mice. We provide evidence that cathelicidin is implicated in NS-associated skin inflammation in vivo. Therefore, marketed products that are known to reduce cathelicidin expression could be repurposed for the management of NS.
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a proinflammatory role of klk6 protease in Netherton Syndrome
Journal of Dermatological Science, 2019Co-Authors: Eleni Zingkou, Georgios Pampalakis, Eleni Charla, Pauline Nauroy, Dimitra Kiritsi, Georgia SotiropoulouAbstract:Abstract Background Netherton Syndrome (NS) is a rare but severe type of ichthyosis characterized by atopy, allergies, and potentially lethal skin overdesquamation associated with highly elevated proteolytic activities in LEKTI-deficient epidermis. NS symptoms are recapitulated in Spink5−/− mouse where the gene encoding Lekti has been invalidated. Spink5−/− mice die within 5 h from birth due to their severe skin barrier defect leading to dehydration. Spink5−/− mice also serve as a model for atopic dermatitis. The KLK6 protease is expressed by epidermal keratinocytes and shown in vitro to cleave desmosomal components. Objective To investigate in vivo whether KLK6 is implicated in epidermal overdesquamation and/or inflammation associated with NS. Methods The role of KLK6 was evaluated by generating Spink5−/−Klk6−/− double knockout mice. The phenotype was assessed by macroscopic observation, immunohistochemistry for differentiation markers, in situ zymography for proteolysis, and quantification of proinflammatory cytokines. Results Elimination of Klk6 in Spink5−/− remarkably suppresses the expression of Tslp, a major itching-inducing factor and driver of allergic reactions. Tnfα and the Th17 promoting cytokine Il-23 were also suppressed. Spink5−/−Klk6−/− mice display normalized keratinocyte differentiation, nevertheless, epidermal proteolytic activities and the associated overdesquamation were not ameliorated, and Spink5−/−Klk6−/− still died from a severe epidermal barrier defect as the Spink5−/−. Conclusions Ablation of Klk6 largely suppresses epidermal inflammation but cannot rescue overdesquamation leading to the lethal NS phenotype. Nonetheless, our findings demonstrate for the first time that KLK6 is implicated in skin inflammation and may represent a novel druggable target for NS and other inflammatory conditions e.g. atopic dermatitis.
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klk5 inactivation reverses cutaneous hallmarks of Netherton Syndrome
PLOS Genetics, 2015Co-Authors: Laetitia Furio, Georgios Pampalakis, Iacovos P. Michael, Andras Nagy, Georgia Sotiropoulou, Alain HovnanianAbstract:Netherton Syndrome (NS) is a rare and severe autosomal recessive skin disease which can be life-threatening in infants. The disease is characterized by extensive skin desquamation, inflammation, allergic manifestations and hair shaft defects. NS is caused by loss-of-function mutations in SPINK5 encoding the LEKTI serine protease inhibitor. LEKTI deficiency results in unopposed activities of kallikrein-related peptidases (KLKs) and aberrantly increased proteolysis in the epidermis. Spink5⁻/⁻ mice recapitulate the NS phenotype, display enhanced epidermal Klk5 and Klk7 protease activities and die within a few hours after birth because of a severe skin barrier defect. However the contribution of these various proteases in the physiopathology remains to be determined. In this study, we developed a new murine model in which Klk5 and Spink5 were both knocked out to assess whether Klk5 deletion is sufficient to reverse the NS phenotype in Spink5⁻/⁻ mice. By repeated intercrossing between Klk5⁻/⁻ mice with Spink5⁻/⁻ mice, we generated Spink5⁻/⁻Klk5⁻/⁻ animals. We showed that Klk5 knock-out in Lekti-deficient newborn mice rescues neonatal lethality, reverses the severe skin barrier defect, restores epidermal structure and prevents skin inflammation. Specifically, using in situ zymography and specific protease substrates, we showed that Klk5 knockout reduced epidermal proteolytic activity, particularly its downstream targets proteases KLK7, KLK14 and ELA2. By immunostaining, western blot, histology and electron microscopy analyses, we provide evidence that desmosomes and corneodesmosomes remain intact and that epidermal differentiation is restored in Spink5⁻/⁻Klk5⁻/⁻. Quantitative RT-PCR analyses and immunostainings revealed absence of inflammation and allergy in Spink5⁻/⁻Klk5⁻/⁻ skin. Notably, Il-1β, Il17A and Tslp levels were normalized. Our results provide in vivo evidence that KLK5 knockout is sufficient to reverse NS-like symptoms manifested in Spink5⁻/⁻ skin. These findings illustrate the crucial role of protease regulation in skin homeostasis and inflammation, and establish KLK5 inhibition as a major therapeutic target for NS.
Stephane Chavanas - One of the best experts on this subject based on the ideXlab platform.
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Netherton Syndrome disease expression and spectrum of spink5 mutations in 21 families
Journal of Investigative Dermatology, 2002Co-Authors: Emmanuelle Bitoun, Stephane Chavanas, Christine Bodemer, D Hamelteillac, Alan D Irvine, Lorne Lonie, Mauro Paradisi, Shinichi Ansai, Yoshihiko MitsuhashiAbstract:Netherton Syndrome is a severe autosomal recessive skin disorder characterized by congenital erythroderma, a specific hair-shaft abnormality, and atopic manifestations with high IgE levels. Recently, we identified SPINK5, which encodes the serine protease inhibitor Kazal-type 5 protein (LEKTI), as the defective gene in Netherton Syndrome. Here we describe the intron-exon organization of the gene and characterize the SPINK5 mutations in patients from 21 families of different geographic origin, using denaturing high performance liquid chromatography and direct sequencing. We identified 18 mutations, of which 13 were novel and seven (39%) were recurrent. The majority of the mutations were clustered between exons 1–8 and exons 21–26. They comprised four nonsense mutations (22%), eight frameshift insertions or deletions (44%), and six splice-site defects (33%). All mutations predict the formation of premature termination codons. Northern blot analysis showed variable reduction of SPINK5 mutant transcript levels, suggesting variable efficiency of nonsense-mediated mRNA decay. Seven patients were homozygotes, eight were compound heterozygotes, and five were heterozygotes with only one identifiable SPINK5 mutation. Five mutations, one of which resulted in perinatal lethal disease in three families, were associated with certain ethnic groups. We also describe 45 intragenic polymorphisms in the patients studied. The clinical features of erythroderma, trichorrhexis invaginata, and atopic manifestations were present in the majority of affected individuals and ichthyosis linearis circumflexa was seen in 12 out of 24 patients. Interfamilial and intrafamilial variation in disease severity was observed, with no clear correlation between mutations and phenotype, suggesting that the degree of severity may be affected by other factors.
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The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton Syndrome: Implications for mutation detection and first case of prenatal diagnosis
Journal of Investigative Dermatology, 2001Co-Authors: Eli Sprecher, Stephane Chavanas, Shivan Amin, Karl Nielsen, Ellen Pfendner, Jouni Uitto, Gabriele Richard, John J. Digiovanna, Julie S. Prendiville, Robert A. SilvermanAbstract:The Comel–Netherton Syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comel–Netherton Syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comel–Netherton Syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comel–Netherton Syndrome across families of different origins. The Comel–Netherton Syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comel–Netherton Syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comel–Netherton Syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype–phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comel–Netherton Syndrome.
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mutations in spink5 encoding a serine protease inhibitor cause Netherton Syndrome
Nature Genetics, 2000Co-Authors: Stephane Chavanas, Christine Bodemer, Ariane Rochat, D Hamelteillac, Alan D Irvine, Jeanlouis Bonafe, John D Wilkinson, Alain Taieb, Yann Barrandon, J.i. HarperAbstract:We describe here eleven different mutations in SPINK5, encoding the serine protease inhibitor LEKTI, in 13 families with Netherton Syndrome (NS, MIM256500). Most of these mutations predict premature termination codons. These results disclose a critical role of SPINK5 in epidermal barrier function and immunity, and suggest a new pathway for high serum IgE levels and atopic manifestations.
Eleni Zingkou - One of the best experts on this subject based on the ideXlab platform.
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cathelicidin represents a new target for manipulation of skin inflammation in Netherton Syndrome
Biochimica et Biophysica Acta, 2020Co-Authors: Eleni Zingkou, Georgios Pampalakis, Georgia SotiropoulouAbstract:Abstract Netherton Syndrome (NS) is a severe ichthyosis caused by inactivating mutations in the SPINK5 gene encoding the serine protease inhibitor LEKTI. Spink5−/− mice recapitulate NS and die perinatally from extensive dehydration as a result of a severe defect of the epidermal barrier. We showed that deletion of Klk5 in Spink5−/− rescues neonatal lethality (Furio et al., 2015). However, Spink5−/−Klk5−/− mice developed skin shedding and inflammation during the first week from birth and the majority (70%) succumbed on P7. The remaining mice lived short (i.e. mean survival was 5 months) indicating alternative inflammatory pathways. Since cathelicidin is increased in Spink5−/− epidermis, we investigated whether it could be implicated in NS pathology. Ablation of Camp in Spink5−/− suppressed epidermal inflammation and restored abnormal epidermal differentiation, nevertheless, it failed to inhibit overdesquamation and Spink5−/−Camp−/− succumbed perinatally due to skin barrier defect, similarly to Spink5−/−. Joint invalidation of Klk5 and Camp significantly extended survival of Spink5−/−Klk5−/−Camp−/− mice. We provide evidence that cathelicidin is implicated in NS-associated skin inflammation in vivo. Therefore, marketed products that are known to reduce cathelicidin expression could be repurposed for the management of NS.
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a proinflammatory role of klk6 protease in Netherton Syndrome
Journal of Dermatological Science, 2019Co-Authors: Eleni Zingkou, Georgios Pampalakis, Eleni Charla, Pauline Nauroy, Dimitra Kiritsi, Georgia SotiropoulouAbstract:Abstract Background Netherton Syndrome (NS) is a rare but severe type of ichthyosis characterized by atopy, allergies, and potentially lethal skin overdesquamation associated with highly elevated proteolytic activities in LEKTI-deficient epidermis. NS symptoms are recapitulated in Spink5−/− mouse where the gene encoding Lekti has been invalidated. Spink5−/− mice die within 5 h from birth due to their severe skin barrier defect leading to dehydration. Spink5−/− mice also serve as a model for atopic dermatitis. The KLK6 protease is expressed by epidermal keratinocytes and shown in vitro to cleave desmosomal components. Objective To investigate in vivo whether KLK6 is implicated in epidermal overdesquamation and/or inflammation associated with NS. Methods The role of KLK6 was evaluated by generating Spink5−/−Klk6−/− double knockout mice. The phenotype was assessed by macroscopic observation, immunohistochemistry for differentiation markers, in situ zymography for proteolysis, and quantification of proinflammatory cytokines. Results Elimination of Klk6 in Spink5−/− remarkably suppresses the expression of Tslp, a major itching-inducing factor and driver of allergic reactions. Tnfα and the Th17 promoting cytokine Il-23 were also suppressed. Spink5−/−Klk6−/− mice display normalized keratinocyte differentiation, nevertheless, epidermal proteolytic activities and the associated overdesquamation were not ameliorated, and Spink5−/−Klk6−/− still died from a severe epidermal barrier defect as the Spink5−/−. Conclusions Ablation of Klk6 largely suppresses epidermal inflammation but cannot rescue overdesquamation leading to the lethal NS phenotype. Nonetheless, our findings demonstrate for the first time that KLK6 is implicated in skin inflammation and may represent a novel druggable target for NS and other inflammatory conditions e.g. atopic dermatitis.
