A rare CTSC mutation in Papillon-Lefèvre Syndrome results in abolished serine protease activity and reduced NET formation but otherwise normal neutrophil function.

Papillon-Lefèvre Syndrome (PLS) is an autosomal recessive monogenic disease caused by loss-of-function mutations in the CTSC gene, thus preventing the synthesis of the protease Cathepsin C (CTSC) in a proteolytically active form. CTSC is responsible for the activation of the pro-forms of the neutrophil serine proteases (NSPs; Elastase, Proteinase 3 and Cathepsin G), suggesting its involvement in a variety of neutrophil functions. In PLS neutrophils, the lack of CTSC protease activity leads to inactivity of the NSPs. Clinically, PLS is characterized by an early, typically pre-pubertal, onset of severe periodontal pathology and palmoplantar hyperkeratosis. However, PLS is not considered an immune deficiency as patients do not typically suffer from recurrent and severe (bacterial and fungal) infections. In this study we investigated an unusual CTSC mutation in two siblings with PLS, a 503A>G substitution in exon 4 of the CTSC gene, expected to result in an amino acid replacement from tyrosine to cysteine at position 168 of the CTSC protein. Both patients bearing this mutation presented with pronounced periodontal pathology. The characteristics and functions of neutrophils from patients homozygous for the 503A>G CTSC mutation were compared to another previously described PLS mutation (755A>T), and a small cohort of healthy volunteers. Neutrophil lysates from patients with the 503A>G substitution lacked CTSC protein and did not display any CTSC or NSP activity, yet neutrophil counts, morphology, priming, chemotaxis, radical production, and regulation of apoptosis were without any overt signs of alteration. However, NET formation upon PMA-stimulation was found to be severely depressed, but not abolished, in PLS neutrophils.

Prolonged pharmacological inhibition of cathepsin C results in elimination of neutrophil serine proteases.

Cathepsin C (CatC) is a tetrameric cysteine dipeptidyl aminopeptidase that plays a key role in activation of pro-inflammatory serine protease zymogens by removal of a N-terminal pro-dipeptide sequence. Loss of function mutations in the CatC gene is associated with lack of immune cell serine protease activities and cause Papillon-Lefèvre syndrome (PLS). Also, only very low levels of elastase-like protease zymogens are detected by proteome analysis of neutrophils from PLS patients. Thus, CatC inhibitors represent new alternatives for the treatment of neutrophil protease-driven inflammatory or autoimmune diseases. We aimed to experimentally inactivate and lower neutrophil elastase-like proteases by pharmacological blocking of CatC-dependent maturation in cell-based assays and in vivo. Isolated, immature bone marrow cells from healthy donors pulse-chased in the presence of a new cell permeable cyclopropyl nitrile CatC inhibitor almost totally lack elastase. We confirmed the elimination of neutrophil elastase-like proteases by prolonged inhibition of CatC in a non-human primate. We also showed that neutrophils lacking elastase-like protease activities were still recruited to inflammatory sites. These preclinical results demonstrate that the disappearance of neutrophil elastase-like proteases as observed in PLS patients can be achieved by pharmacological inhibition of bone marrow CatC. Such a transitory inhibition of CatC might thus help to rebalance the protease load during chronic inflammatory diseases, which opens new perspectives for therapeutic applications in humans.

[Screening of CTSC gene mutations in a Chinese pedigree affected with Papillon-Lefevre syndrome].

OBJECTIVE: To analyze the clinical phenotype of a Chinese pedigree affected with Papillon-Lefevre syndrome(PLS) and detect mutation of CTSC gene. METHODS: Clinical phenotypes were noted, and oral examination for the proband was carried out for the clinical diagnosis of PLS. PCR and Sanger sequencing were used to identify potential mutation of the CTSC gene. Functional effect of the mutation was predicted with SIFT and PolyPhen-2. Swiss-Port was used to predict the tertiary structure of wild type and mutant proteins. The mRNA and protein expression were analyzed by real-time PCR and Western blotting. RESULTS: A homozygous mutation c.901G>A (p.G301S) in exon 7 of CTSC gene was identified in the patient. Both parents of the patient had carried a heterozygous c.901G>A mutation. The mutation was located in the conserved region of CTSC enzyme and was predicted to be damaging by changing the structure of the protein, which could affect the activity of Cathepsin C. However, no significant difference was found in the expression of p.G301S variant at the mRNA and protein levels compared with that of the wild type CTSC gene. CONCLUSION: The c.901G>A mutation of the CTSC gene was first reported in China, which has expanded its mutation spectrum.

NSP4 is stored in azurophil granules and released by activated neutrophils as active endoprotease with restricted specificity.

Whereas neutrophil elastase, cathepsin G, and proteinase 3 have been known as granule-associated serine proteases of neutrophils for decades, a fourth member, called neutrophil serine protease 4 (NSP4), was just recently described and provisionally characterized. In this study, we identified NSP4 as a novel azurophil granule protein of neutrophils by Western blot analyses of subcellular fractions as well as by RT-PCR analyses of neutrophil precursors from human bone marrow. The highest mRNA levels were observed in myeloblasts and promyelocytes, similar to myeloperoxidase, a marker of azurophil granules. To determine the extended sequence specificity of recombinant NSP4, we used an iterative fluorescence resonance energy transfer-based optimization strategy. In total, 142 different peptide substrates with arginine in P1 and variations at the P1', P2', P3, P4, and P2 positions were tested. This enabled us to construct an α1-proteinase inhibitor variant (Ile-Lys-Pro-Arg-/-Ser-Ile-Pro) with high specificity for NSP4. This tailor-made serpin was shown to form covalent complexes with all NSP4 of neutrophil lysates and supernatants of activated neutrophils, indicating that NSP4 is fully processed and stored as an already activated enzyme in azurophil granules. Moreover, cathepsin C was identified as the activator of NSP4 in vivo, as cathepsin C deficiency resulted in a complete absence of NSP4 in a Papillon-Lefèvre patient. Our in-depth analysis of NSP4 establishes this arginine-specific protease as a genuine member of preactivated serine proteases stored in azurophil granules of human neutrophils.

A novel seven-base deletion of the CTSC gene identified in a Hungarian family with Papillon-Lefèvre syndrome.

Papillon-Lefévre syndrome (PLS; OMIM 245000) is a rare autosomal recessive condition characterized by symmetrical palmoplantar hyperkeratosis and periodontal inflammation, causing loss of both the deciduous and permanent teeth. PLS develops due to mutations in the cathepsin C gene, CTSC. Recently we have identified a Hungarian PLS family with two affected siblings. Direct sequencing of the coding regions of the CTSC gene revealed a novel seven-base deletion leading to frameshift and early stop codon in the fourth exon of the CTSC gene (c.681delCATACAT, p.T188fsX199). The affected family members carried the mutation in homozygous form, while the clinically unaffected family members carried the mutation in heterozygous form. The unrelated controls carried only the wild type sequence. In this paper we report a novel homozygous deletion of seven bases on the CTSC gene leading to the development of PLS. Since consanguineous marriage was unknown in the investigated family, the presence of the homozygous seven-base deletion of the CTSC gene may suggest that the parents are close relatives.

Neutrophil elastase, proteinase 3, and cathepsin G as therapeutic targets in human diseases.

Polymorphonuclear neutrophils are the first cells recruited to inflammatory sites and form the earliest line of defense against invading microorganisms. Neutrophil elastase, proteinase 3, and cathepsin G are three hematopoietic serine proteases stored in large quantities in neutrophil cytoplasmic azurophilic granules. They act in combination with reactive oxygen species to help degrade engulfed microorganisms inside phagolysosomes. These proteases are also externalized in an active form during neutrophil activation at inflammatory sites, thus contributing to the regulation of inflammatory and immune responses. As multifunctional proteases, they also play a regulatory role in noninfectious inflammatory diseases. Mutations in the ELA2/ELANE gene, encoding neutrophil elastase, are the cause of human congenital neutropenia. Neutrophil membrane-bound proteinase 3 serves as an autoantigen in Wegener granulomatosis, a systemic autoimmune vasculitis. All three proteases are affected by mutations of the gene (CTSC) encoding dipeptidyl peptidase I, a protease required for activation of their proform before storage in cytoplasmic granules. Mutations of CTSC cause Papillon-Lefèvre syndrome. Because of their roles in host defense and disease, elastase, proteinase 3, and cathepsin G are of interest as potential therapeutic targets. In this review, we describe the physicochemical functions of these proteases, toward a goal of better delineating their role in human diseases and identifying new therapeutic strategies based on the modulation of their bioavailability and activity. We also describe how nonhuman primate experimental models could assist with testing the efficacy of proposed therapeutic strategies.

Novel cathepsin C mutation in a Brazilian family with Papillon-Lefèvre syndrome: case report and mutation update.

PURPOSE: Papilion-Lefèvre syndrome (PLS) is a rare autosomal recessive disorder that involves palmoplantar keratosis (PK) and severe aggressive periodontitis. Cathepsin C (CTSC) gene mutations are etiologic for PLS, with more than 60 different mutations reported in different ethnic groups worldwide. The purpose of this study was to report a novel cathepsin C mutation in a Brazilian patient. METHODS: A 4-year-old boy presented with aggressive periodontitis, recession, missing teeth, and hyperkeratosis of the palms of hands and soles. Peripheral blood samples were obtained from family members for genomic DNA isolation. The coding region and exon/intron boundaries of the CTSC gene were amplified and sequenced. RESULTS: The patient had a PLS phenotype, which included PK and early-onset severe periodontitis. Sequence analysis showed a novel CTSC mutation (c.267-268del) present in the homozygous state. CONCLUSION: This report described a novel mutation in a family with Brazilian Papillon-Lefèvre syndrome and presented a review of all cathepsin C (65) mutations reported to date.

Functional Cathepsin C mutations cause different Papillon-Lefèvre syndrome phenotypes.

AIM: The autosomal-recessive Papillon-Lefèvre syndrome (PLS) is characterized by severe aggressive periodontitis, combined with palmoplantar hyperkeratosis, and is caused by mutations in the Cathepsin C (CTSC) gene. This study aimed to identify CTSC mutations in different PLS phenotypes, including atypical forms and isolated pre-pubertal aggressive periodontitis (PAP). MATERIAL AND METHODS: Thirteen families with different phenotypes were analysed by direct sequencing of the entire coding region and the regulatory regions of CTSC. The function of novel mutations was tested with enzyme activity measurements. RESULTS: In 11 of 13 families, 12 different pathogenic CTSC mutations were found in 10 typical PLS patients, three atypical cases and one PAP patient. Out of four novel mutations, three result in protein truncation and are thus considered to be pathogenic. The homozygous c.854C>T nucleotide exchange (p.P285L) was associated with an almost complete loss of enzyme activity. The observed phenotypic heterogeneity could not be associated with specific genotypes. CONCLUSIONS: The phenotypic variability of the PLS associated with an identical genetic background may reflect the influence of additional genetic or environmental factors on disease characteristics. CTSC mutation analyses should be considered for differential diagnosis in all children suffering from severe aggressive periodontitis.

[Novel mutations of cathepsin C gene in two Chinese patients with Papillon-Lefèvre syndrome].

OBJECTIVE: To investigate the mutational characteristics of cathepsin C (CTSC) gene in two Chinese patients with Papillon-Lefèvre syndrome (PLS), and provide molecular basis for research of the pathogenesis of PLS. METHODS: Peripheral blood samples were obtained from patients and their parents respectively. Genomic DNA were extracted after consents. Polymerase chain reaction, direct DNA sequencing and restriction enzyme reaction were performed to screen mutations of CTSC gene. RESULTS: Compound heterozygous mutations of CTSC gene were identified in the two patients. Patient I carried the G139R and S260P mutations, patient II had the R250X and C258W mutations. The parents were heterozygous carriers without the clinical feature of PLS. None of the mutations were detected in normal controls. Furthermore, the S260P and C258W changes were novel mutations of CTSC gene, which had not been reported previously. CONCLUSIONS: Mutations of CTSC gene are responsible for the phenotype of Papillon-Lefèvre syndrome in two Chinese patients. The results extend the mutation spectrum of CTSC gene and also provide basis for gene diagnosis of PLS in China.

Role of polymorphonuclear leukocyte-derived serine proteinases in defense against Actinobacillus actinomycetemcomitans.

Periodontitis is a chronic destructive infection of the tooth-supportive tissues, which is caused by pathogenic bacteria such as Actinobacillus actinomycetemcomitans. A severe form of periodontitis is found in Papillon-Lefèvre syndrome (PLS), an inheritable disease caused by loss-of-function mutations in the cathepsin C gene. Recently, we demonstrated that these patients lack the activity of the polymorphonuclear leukocyte (PMN)-derived serine proteinases elastase, cathepsin G, and proteinase 3. In the present study we identified possible pathways along which serine proteinases may be involved in the defense against A. actinomycetemcomitans. Serine proteinases are capable to convert the PMN-derived hCAP-18 into LL-37, an antimicrobial peptide with activity against A. actinomycetemcomitans. We found that the PMNs of PLS patients released lower levels of LL-37. Furthermore, because of their deficiency in serine proteases, the PMNs of PLS patients were incapable of neutralizing the leukotoxin produced by this pathogen, which resulted in increased cell damage. Finally, the capacity of PMNs from PLS patients to kill A. actinomycetemcomitans in an anaerobic environment, such as that found in the periodontal pocket, seemed to be reduced. Our report demonstrates a mechanism that suggests a direct link between an inheritable defect in PMN functioning and difficulty in coping with a periodontitis-associated pathogen.

Description of two new cathepsin C gene mutations in patients with Papillon-Lefèvre syndrome.

BACKGROUND: Papillon-Lefèvre syndrome (PLS) is a rare autosomal disorder characterized by severe periodontitis and palmar plantar hyperkeratosis (PPK). PLS is caused by mutations in the cathepsin C (CTSC) gene. Dipeptidyl peptidase I (DPPI) encoded by the CTSC locus removes dipeptides from the amino terminus of the protein substrate and mainly plays an important role in immune and inflammatory processes. Several mutations have been reported in this gene in patients with PLS. This study reports two novel deletion mutation of the CTSC gene in two Indian families with PLS. METHODS: Peripheral blood samples were obtained for genomic DNA isolation from individuals belonging to two Indian families. Exon-specific intronic primers were used to amplify DNA from all individuals, and the PCR products were subsequently sequenced to detect the mutations. Heteroduplex analysis (HDA) was used to confirm heterozygosity and to determine the presence of mutations in control individuals. RESULTS: All patients from both families had a classic PLS phenotype, which included PPK and severe periodontitis. Sequence analysis of the CTSC gene revealed two novel deletion mutations, one (1213-1215delCAT) in exon 7 and the other (629-630delGA) in exon 4 of the CTSC gene. For both mutations, the patients were homozygous, whereas the parents were heterozygous. CONCLUSIONS: This study reports two novel deletion mutations in two Indian families with PLS. One of the mutations introduces a premature stop codon, thereby producing a truncated protein. In the other case, the mutation observed leads to the loss of a highly conserved histidine molecule that is present in the active site of the enzyme. In both cases, mutations may result in a conformation change, causing loss of the enzymatic activity.

A family with Papillon-Lefevre syndrome reveals a requirement for cathepsin C in granzyme B activation and NK cell cytolytic activity.

Activation of granzyme B, a key cytolytic effector molecule of natural killer (NK) cells, requires removal of an N-terminal pro-domain. In mice, cathepsin C is required for granzyme processing and normal NK cell cytolytic function, whereas in patients with Papillon-Lefèvre syndrome (PLS), loss-of-function mutations in cathepsin C do not affect lymphokine activated killer (LAK) cell function. Here we demonstrate that resting PLS NK cells do have a cytolytic defect and fail to induce the caspase cascade in target cells. NK cells from these patients contain inactive granzyme B, indicating that cathepsin C is required for granzyme B activation in unstimulated human NK cells. However, in vitro activation of PLS NK cells with interleukin-2 restores cytolytic function and granzyme B activity by a cathepsin C-independent mechanism. This is the first documented example of a human mutation affecting granzyme B activity and highlights the importance of cathepsin C in human NK cell function.

Clinical, genetic, and biochemical findings in two siblings with Papillon-Lefèvre Syndrome.

BACKGROUND: Papillon-Lefèvre Syndrome (PLS) is an autosomal recessive disease characterized by palmoplantar hyperkeratosis and severe periodontitis affecting both primary and secondary dentitions. Cathepsin C (CTSC) gene mutations are etiologic for PLS. The resultant loss of CTSC function is responsible for the severe periodontal destruction seen clinically. METHODS: A 4-year-old female (case 1) and her 10-year-old sister (case 2) presented with palmoplantar skin lesions, tooth mobility, and advanced periodontitis. Based on clinical findings, the cases were diagnosed with PLS. Mutational screening of the CTSC gene was conducted for the cases, and their clinically unaffected parents and brother. Biochemical analysis was performed for CTSC, cathepsin G (CTSG), and elastase activity in neutrophils for all members of the nuclear family. The initial treatment included oral hygiene instruction, scaling and root planing, and systemic amoxicillin-metronidazole therapy. RESULTS: CTSC mutational screening identified a c.415G>A transition mutation. In the homozygous state, this mutation was associated with an almost complete loss of activity of CTSC, CTSG, and elastase. Although monthly visits, including scaling, polishing, and 0.2% chlorhexidine digluconate irrigation were performed to stabilize the periodontal condition, case 1 lost all her primary teeth. In case 2, some of the permanent teeth could be maintained. CONCLUSIONS: This report describes two siblings with a cathepsin C gene mutation that is associated with the inactivity of cathepsin C and several neutrophil serine proteases. The failure of patients to respond to periodontal treatment is discussed in the context of these biological findings.

Papillon-Lefèvre syndrome with albinism: a review of the literature and report of 2 brothers.

BACKGROUND: Papillon-Lefèvre syndrome (PLS) is a very rare autosomal recessive disorder characterized by palmoplantar hyperkeratosis and severe early onset of destructive periodontitis leading to premature loss of both primary and permanent dentitions. The etiopathogenesis of the condition suggests that there is a genetic basis for susceptibility to specific virulent pathogens. Variation in the clinical presentation of PLS has recently been observed. OBJECTIVE: The objective was to present the first report, which describes the concurrence of PLS and albinism. The etiology, pathology, and management of the condition were reviewed and genetic analysis was performed. SUBJECTS AND CLINICAL PRESENTATION: The probands are Jordanian brothers aged 13 and 20 years on their initial presentation. The parents were second cousins and not affected. The patients exhibited the typical clinical features of PLS with type 1 oculocutaneous albinism (OCA1). They also had increased susceptibility to infection manifested in recurrent tonsillitis, respiratory tract infection, pyoderma, onychogryphosis, and other pathosis. Skin biopsy demonstrated hyperkeratosis, focal parakeratosis, hypergranulosis, and acanthosis. Ectopic calcification of the dura was noticed in one of the probands. Hematological parameters tested were within the normal limits. The probands were tested for mutations in the causative genes of PLS and OCA1, cathepsin C (CTSC), and tyrosinase, respectively. Independent mutations (c.318-1G>A and c.817G>C/p.W272C) were identified in CTSC and tyrosinase, respectively. The probands were homozygous and their sister who had only PLS was homozygous for the same (CTSC) mutation but heterozygous for tyrosinase gene. CONCLUSION: We hope that this report of coinheritance PLS and albinism will initiate further investigations to disclose other possible variations that may enhance our knowledge on gene mutations of this intriguing syndrome.

Papillon-Lefèvre syndrome: correlating the molecular, cellular, and clinical consequences of cathepsin C/dipeptidyl peptidase I deficiency in humans.

A variety of neutral serine proteases are important for the effector functions of immune cells. The neutrophil-derived serine proteases cathepsin G and neutrophil elastase are implicated in the host defense against invading bacterial and fungal pathogens. Likewise, the cytotoxic lymphocyte and NK cell granule-associated granzymes A and B are important for the elimination of virus-infected cells. The activation of many of these serine proteases depends on the N-terminal processing activity of the lysosomal cysteine protease cathepsin C/dipeptidyl peptidase I (DPPI). Although mice deficient in DPPI have defects in serine protease activation in multiple cellular compartments, the role of DPPI for human serine protease activation is largely undefined. Papillon-Lefevre syndrome (PLS) is a rare autosomal recessive disease associated with loss-of-function mutations in the DPPI gene locus. In this study, we established that the loss of DPPI activity is associated with severe reduction in the activity and stability of neutrophil-derived serine proteases. Surprisingly, patients with PLS retain significant granzyme activities in a cytotoxic lymphocyte compartment (lymphokine-activated killer) and have normal lymphokine-activated killer-mediated cytotoxicity against K562 cells. Neutrophils from patients with PLS do not uniformly have a defect in their ability to kill Staphylococcus aureus and Escherichia coli, suggesting that serine proteases do not represent the major mechanism used by human neutrophils for killing common bacteria. Therefore, this study defines the consequences of DPPI deficiency for the activation of several immune cell serine proteases in humans, and provides a molecular explanation for the lack of a generalized T cell immunodeficiency phenotype in patients with PLS.

Tissue plasminogen activator (t-PA) and placental plasminogen activator inhibitor (PAI-2) in gingival crevicular fluid from patients with Papillon-Lefèvre syndrome.

OBJECTIVES: Numerous patients with Papillon-Lefèvre syndrome (PLS) express a severe periodontal inflammation that results in premature loss of deciduous and permanent teeth. The plasminogen activating (PA) system is involved in physiological and pathological processes including epithelial healing, extracellular proteolysis and local inflammatory reactions. The aim of the study was to explore a possible role of the PA system in patients with PLS. MATERIAL AND METHODS: Samples of gingival crevicular fluid (GCF) were collected from areas with gingival infection in 20 patients with PLS and in 20 healthy controls. The concentration of tissue plasminogen activator (t-PA) and inhibitor (PAI-2) was measured with ELISA. RESULTS: The median level of PAI-2 was significantly higher (p < 0.01) in PLS patients than in the controls, while the median value of t-PA did not differ between the groups. No difference in t-PA or PAI-2 levels was found regarding age, gender or presence of active periodontal disease. CONCLUSION: The findings indicate an atypical activity of the PA system with a disturbed epithelial function in PLS patients, suggesting that the periodontal destruction seen in patients with PLS is secondary to a hereditary defect in the defense system.

Novel mutations in the cathepsin C gene in patients with pre-pubertal aggressive periodontitis and Papillon-Lefèvre syndrome.

Aggressive periodontitis (AP) in pre-pubertal children is often associated with genetic disorders like Papillon-Lefèvre syndrome (PLS). PLS is caused by mutations in the cathepsin C (CTSC) gene. We report a novel CTSC mutation (c.566-572del) in an otherwise healthy AP child and two novel compound heterozygous mutations (c.947T>G, c.1268G>C) in a PLS patient. We conclude that at least a subset of pre-pubertal AP is due to CTSC mutations and therefore may be an allelic variant of PLS.

Loss-of-function mutations in cathepsin C in two families with Papillon-Lefèvre syndrome are associated with deficiency of serine proteinases in PMNs.

Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive disease that involves severe periodontitis and hyperkeratosis of the hand palms and foot soles. Recently it was found that PLS patients carry loss-of-function mutations in the gene encoding cathepsin C (CTSC). In the present study we have analyzed the CTSC gene in two unrelated families with PLS. In the first non-consanguineous family, mutation analysis revealed the previously reported c.815G>C/p.R272P mutation. The second consanguineous family displayed a c.1213C>A mutation which resulted in the novel mutation p.H405N and is the first mutation described in the active site of the enzyme. The PLS patients had, next to the absence of cathepsin C activity in polymorphonuclear leukocytes (PMNs), no activity of the three serine proteinases elastase, cathepsin G and proteinase 3. Serine proteinases are supposed to be important in both the innate and adaptive immune systems. Their absence in PLS patients could explain the inadequate defense to periodontal infection.