Cytokine production by leukocytes of Papillon-Lefèvre syndrome patients in whole blood cultures

Cathepsin C in health and disease: from structural insights to therapeutic prospects

Cathepsin C (CTSC) is a lysosomal cysteine protease constitutively expressed at high levels in the lung, kidney, liver, and spleen. It plays a key role in the activation of serine proteases in cytotoxic T cells, natural killer cells (granzymes A and B), mast cells (chymase and tryptase) and neutrophils (cathepsin G, neutrophil elastase, proteinase 3) underscoring its pivotal significance in immune and inflammatory defenses. Here, we comprehensively review the structural attributes, synthesis, and function of CTSC, with a focus on its variants implicated in the etiopathology of several syndromes associated with neutrophil serine proteases, including Papillon-Lefevre syndrome (PLS), Haim-Munk Syndrome (HMS), and aggressive periodontitis (AP). These syndromes are characterized by palmoplantar hyperkeratosis, and early-onset periodontitis (severe gum disease) resulting in premature tooth loss. Due to the critical role played by CTSC in these and several other conditions it is being explored as a potential therapeutic target for autoimmune and inflammatory disorders. The review also discusses in depth the gene variants of CTSC, and in particular their postulated association with chronic obstructive pulmonary disease (COPD), COVID-19, various cancers, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, sudden cardiac death (SCD), atherosclerotic vascular disease, and neuroinflammatory disease. Finally, the therapeutic potential of CTSC across a range of human diseases is discussed.

Neutrophil-Derived Proteases in Lung Inflammation: Old Players and New Prospects

Neutrophil-derived proteases are critical to the pathology of many inflammatory lung diseases, both chronic and acute. These abundant enzymes play roles in key neutrophil functions, such as neutrophil extracellular trap formation and reactive oxygen species release. They may also be released, inducing tissue damage and loss of tissue function. Historically, the neutrophil serine proteases (NSPs) have been the main subject of neutrophil protease research. Despite highly promising cell-based and animal model work, clinical trials involving the inhibition of NSPs have shown mixed results in lung disease patients. As such, the cutting edge of neutrophil-derived protease research has shifted to proteases that have had little-to-no research in neutrophils to date. These include the cysteine and serine cathepsins, the metzincins and the calpains, among others. This review aims to outline the previous work carried out on NSPs, including the shortcomings of some of the inhibitor-orientated clinical trials. Our growing understanding of other proteases involved in neutrophil function and neutrophilic lung inflammation will then be discussed. Additionally, the potential of targeting these more obscure neutrophil proteases will be highlighted, as they may represent new targets for inhibitor-based treatments of neutrophil-mediated lung inflammation.

The CTSC-RAB38 Fusion Transcript Is Associated With the Risk of Hemorrhage in Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are congenital anomalies of blood vessels that cause intracranial hemorrhage in children and young adults. Chromosomal rearrangements and fusion genes play an important role in tumor pathogenesis, though the role of fusion genes in bAVM pathophysiological processes is unclear. The aim of this study was to identify fusion transcripts in bAVMs and analyze their effects. To identify fusion transcripts associated with bAVM, RNA sequencing was performed on 73 samples, including 66 bAVM and 7 normal cerebrovascular samples, followed by STAR-Fusion analysis. Reverse transcription polymerase chain reaction and Sanger sequencing were applied to verify fusion transcripts. Functional pathway analysis was performed to identify potential effects of different fusion types. A total of 21 fusion transcripts were detected. Cathepsin C (CTSC)-Ras-Related Protein Rab-38 (RAB38) was the most common fusion and was detected in 10 of 66 (15%) bAVM samples. In CTSC-RAB38 fusion-positive samples, CTSC and RAB38 expression was significantly increased and activated immune/inflammatory signaling. Clinically, CTSC-RAB38 fusion bAVM cases had a higher hemorrhage rate than non-CTSC-RAB38 bAVM cases (p < 0.05). Our study identified recurrent CTSC-RAB38 fusion transcripts in bAVMs, which may be associated with bAVM hemorrhage by promoting immune/inflammatory signaling.

Diagnosis of Papillon-Lefèvre syndrome: review of the literature and a case report

Papillon-Lefëvre syndrome (PLS), classified as ectodermal dysplasia, is an autosomal recessive condition related to the cathepsin C (CTSC) gene mutation. The first clinical symptoms, occurring most commonly between the ages of 1 and 4, are palmoplantar hyperkeratosis and also periodontitis resulting in the loss of most or all teeth in the same sequence in which they erupted. Most often the redness of palms and soles precede the occurrence of keratoderma. Moreover, excessive sweating, moderate mental retardation, the tendency to purulent skin and internal organs infection may occur. Lack of cathepsin seems to have a crucial role in the intensity of symptoms. In most of the patients, there can be observed impairment of phagocytosis and chemotaxis of neutrophils, granulocytes, leukocytes and cytotoxic lesion of fibroblasts and macrophages. Also, functional impairment of lymphocytes, neutrophils, and monocytes is observed. The study, using flow cytometry, showed a decreased percentage of T cells CD8+ and increased CD4:CD8 ratio.

Bosentan, a mixed endothelin receptor antagonist, inhibits superoxide anion-induced pain and inflammation in mice

Bosentan is a mixed endothelin receptor antagonist widely used to treat patients with pulmonary arterial hypertension, and the emerging literature suggests bosentan as a potent anti-inflammatory drug. Superoxide anion is produced in large amounts during inflammation, stimulates cytokine production, and thus contributes to inflammation and pain. However, it remains to be determined whether endothelin contributes to the inflammatory response triggered by the superoxide anion. The present study investigated the effects of bosentan in a mouse model of inflammation and pain induced by potassium superoxide, a superoxide anion donor. Male Swiss mice were treated with bosentan (10-100 mg/kg) by oral gavage, 1 h before potassium superoxide injection, and the inflammatory response was evaluated locally and at spinal cord (L4-L6) levels. Bosentan (100 mg/kg) inhibited superoxide anion-induced mechanical and thermal hyperalgesia, overt pain-like behavior (abdominal writhings, paw flinching, and licking), paw edema, myeloperoxidase activity (neutrophil marker) in the paw skin, and leukocyte recruitment in the peritoneal cavity. Bosentan also inhibited superoxide anion-induced interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) production, while it enhanced IL-10 production in the paw skin and spinal cord. Bosentan inhibited the reduction of antioxidant capacity (reduced glutathione, ferric reducing antioxidant power, and ABTS radical scavenging ability) induced by the superoxide anion. Finally, we demonstrated that intraplantar injection of potassium superoxide induces the mRNA expression of prepro-endothelin-1 in the paw skin and spinal cord. In conclusion, our results demonstrated that superoxide anion-induced inflammation, pain, cytokine production, and oxidative stress depend on endothelin; therefore, these responses are amenable to bosentan treatment.

Papillon-Lefevre Syndrome In An Adolescent Female: A Case Study

Papillon-Lefevre Syndrome (PLS) is a rare inherited autosomal-recessive condition with one-third of the patients' showing consanguinity of the parents. Lesions are characterised by palmar-plantar hyperkeratosis and hyperhidrosis. Early onset of periodonditis, severe periodontal destruction in both primary and permanent dentitions, and calcification of the duramater form the three important features of this disease. Here, we present a case of a 14-year-old female who presented to the Department of Oral Medicine and Radiology with a complaint of mobility of the teeth since four months. Oral examination of the patient showed generalised mobility of the teeth. General physical examination of the patient showed dry scaly skin on dorsum of bilateral feet, hands, and knee. The patient had familial history positive for consanguinity. The patient was medically diagnosed as positive for PLS. The patients with PLS show combination of dermatological and dental lesions and it requires the dentist to assume a more prominent role in early treatment and rehabilitation. There is a need for symbiotic and synergetic approach between the two specialties for effective management of this rare disease.