Proteases and HPV-Induced Carcinogenesis.

Persistent infection with Human papillomavirus (HPV) is the main etiologic factor for pre-malignant and malignant cervical lesions. Moreover, HPV is also associated with oropharynx and other anogenital carcinomas. Cancer-causing HPV viruses classified as group 1 carcinogens include 12 HPV types, with HPV 16 and 18 being the most prevalent. High-risk HPVs express two oncoproteins, E6 and E7, the products of which are responsible for the inhibition of p53 and pRB proteins, respectively, in human keratinocytes and cellular immortalization. p53 and pRB are pleiotropic proteins that regulate the activity of several signaling pathways and gene expression. Among the important factors that are augmented in HPV-mediated carcinogenesis, proteases not only control processes involved in cellular carcinogenesis but also control the microenvironment. For instance, genetic polymorphisms of matrix metalloproteinase 1 (MMP-1) are associated with carcinoma invasiveness. Similarly, the serine protease inhibitors hepatocyte growth factor activator inhibitor-1 (HAI-1) and -2 (HAI-2) have been identified as prognostic markers for HPV-dependent cervical carcinomas. This review highlights the most crucial mechanisms involved in HPV-dependent carcinogenesis, and includes a section on the proteolytic cascades that are important for the progression of this disease and their impact on patient health, treatment, and survival.

Kallikrein 5 Inhibition by the Lympho-Epithelial Kazal-Type Related Inhibitor Hinders Matriptase-Dependent Carcinogenesis.

Head and neck squamous cell carcinoma remains challenging to treat with no improvement in survival rates over the past 50 years. Thus, there is an urgent need to discover more reliable therapeutic targets and biomarkers for HNSCC. Matriptase, a type-II transmembrane serine protease, induces malignant transformation in epithelial stem cells through proteolytic activation of pro-HGF and PAR-2, triggering PI3K-AKT-mTOR and NFKB signaling. The serine protease inhibitor lympho-epithelial Kazal-type-related inhibitor (LEKTI) inhibits the matriptase-driven proteolytic pathway, directly blocking kallikreins in epithelial differentiation. Hence, we hypothesized LEKTI could inhibit matriptase-dependent squamous cell carcinogenesis, thus implicating kallikreins in this process. Double-transgenic mice with simultaneous expression of matriptase and LEKTI under the keratin-5 promoter showed a prominent rescue of K5-Matriptase+/0 premalignant phenotype. Notably, in DMBA-induced SCC, heterotopic co-expression of LEKTI and matriptase delayed matriptase-driven tumor incidence and progression. Co-expression of LEKTI reverted altered Kallikrein-5 expression observed in the skin of K5-Matriptase+/0 mice, indicating that matriptase-dependent proteolytic pathway inhibition by LEKTI occurs through kallikreins. Moreover, we showed that Kallikrein-5 is necessary for PAR-2-mediated IL-8 release, YAP1-TAZ/TEAD activation, and matriptase-mediated oral squamous cell carcinoma migration. Collectively, our data identify a third signaling pathway for matriptase-dependent carcinogenesis in vivo. These findings are critical for the identification of more reliable biomarkers and effective therapeutic targets in Head and Neck cancer.

TMPRSS11a is a novel age-altered, tissue specific regulator of migration and wound healing.

Aging is a gradual biological process characterized by a decrease in cellular and organism functions. Aging-related processes involve changes in the expression and activity of several proteins. Here, we identified the transmembrane protease serine 11a (TMPRSS11a) as a new age-specific protein that plays an important role in skin wound healing. TMPRSS11a levels increased with age in rodent and human skin and gingival samples. Strikingly, overexpression of TMPRSS11a decreased cell migration and spreading, and inducing cellular senescence. Mass spectrometry, bioinformatics, and functional analyses revealed that TMPRSS11a interacts with integrin ß1 through an RGD sequence contained within the C-terminal domain and that this motif was relevant for cell migration. Moreover, TMPRSS11a was associated with cellular senescence, as shown by overexpression and downregulation experiments. In agreement with tissue-specific expression of TMPRSS11a, shRNA-mediated downregulation of this protein improved wound healing in the skin, but not in the skeletal muscle of old mice, where TMPRSS11a is undetectable. Collectively, these findings indicate that TMPRSS11a is a tissue-specific factor relevant for wound healing, which becomes elevated with aging, promoting cellular senescence and inhibiting cell migration and skin repair.

Virtual Microscopy as a Learning Tool in Brazilian Medical Education.

Virtual microscopy (VM) is a widely used teaching method in Medical Education in many developed countries. In Brazil, however, this is not the case for most medical schools, considering Brazilian social inequality and uneven access to technology. Recently, the Covid-19 pandemic has also challenged Universities to seek and make a transition toward more effective methods of full-time online education. Thus, the main goal of this work was to verify student's perception and academic performance, assessed upon VM implementation in a Brazilian Medical School. Ribeirao Preto Medical School students answered a 26-question survey with regards to optical microscopy (OM) and VM. Academic performance was compared between participants that were (year of 2019) or were not (year of 2015) exposed to VM. Taken the results together, subjective impressions such as handling, suitability, learning effectiveness, and pleasure using the tools, have shown a higher score for virtual microscopy (median = 29), when compared to optical microscopy (median = 24) with a P-value < 0.001 by Wilcoxon rank test, upon measurement using an ordinal scale. Regarding academic performance, no statistically significant differences were found between groups (P-value = 0.38, Cohen's d = 0.19). Therefore, VM proved to be adequate to the Brazilian medical education in light of Brazilian social contexts and Covid-19 pandemic.

Relative expression of KLK5 to LEKTI is associated with aggressiveness of oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) remains a challenging cancer to treat despite all the advances of the last 50 years. Kallikrein 5 (KLK5) is among the serine proteases implicated in OSCC development. However, whether the activity of KLK5 promotes carcinogenesis is still controversial. Moreover, knowledge regarding the role of the KLK5 cognate inhibitor, Lympho-Epithelial Kazal-Type related Inhibitor (LEKTI), in OSCC is scarce. We have, thus, sought to investigate the importance of KLK5 and LEKTI expression in premalignant and malignant lesions of the oral cavity. METHODS: KLK5 and LEKTI protein expression was evaluated in 301 human samples, which were comprised of non-malignant and malignant lesions of the oral cavity. Moreover, a bioinformatic analysis of the overall survival rate from 517 head and neck squamous cell carcinoma (HNSCC) samples was performed. Additionally, to mimic the uncovered KLK5 to serine peptidase inhibitor (SPINK5) imbalance, the KLK5 gene was abrogated in an OSCC cell line using CRISPR-Cas9 technology. The generated cell line was then used for in vivo and in vitro carcinogenesis related experiments. RESULTS: LEKTI was found to be statistically downregulated in OSCCs, with increased KLK5/SPINK5 mRNA ratio being associated with a shorter overall survival (p = 0.091). Indeed, disruption of KLK5 to SPINK5 balance through the generation of KLK5 null OSCC cells led to smaller xenografted tumors and statistically decreased proliferation rates following multiple time points of BrdU treatment in vitro. CONCLUSION: The association of increased enzyme/inhibitor ratio with poor prognosis indicates KLK5 to SPINK5 relative expression as an important prognostic marker in OSCC.

Matriptase zymogen supports epithelial development, homeostasis and regeneration.

BACKGROUND: Matriptase is a membrane serine protease essential for epithelial development, homeostasis, and regeneration, as well as a central orchestrator of pathogenic pericellular signaling in the context of inflammatory and proliferative diseases. Matriptase is an unusual protease in that its zymogen displays measurable enzymatic activity. RESULTS: Here, we used gain and loss of function genetics to investigate the possible biological functions of zymogen matriptase. Unexpectedly, transgenic mice mis-expressing a zymogen-locked version of matriptase in the epidermis displayed pathologies previously reported for transgenic mice mis-expressing wildtype epidermal matriptase. Equally surprising, mice engineered to express only zymogen-locked endogenous matriptase, unlike matriptase null mice, were viable, developed epithelial barrier function, and regenerated the injured epithelium. Compatible with these observations, wildtype and zymogen-locked matriptase were equipotent activators of PAR-2 inflammatory signaling. CONCLUSION: The study demonstrates that the matriptase zymogen is biologically active and is capable of executing developmental and homeostatic functions of the protease.

Membrane-anchored Serine Protease Matriptase Is a Trigger of Pulmonary Fibrogenesis.

RATIONALE: Idiopathic pulmonary fibrosis (IPF) is a devastating disease that remains refractory to current therapies. OBJECTIVES: To characterize the expression and activity of the membrane-anchored serine protease matriptase in IPF in humans and unravel its potential role in human and experimental pulmonary fibrogenesis. METHODS: Matriptase expression was assessed in tissue specimens from patients with IPF versus control subjects using quantitative reverse transcriptase-polymerase chain reaction, immunohistochemistry, and Western blotting, while matriptase activity was monitored by fluorogenic substrate cleavage. Matriptase-induced fibroproliferative responses and the receptor involved were characterized in human primary pulmonary fibroblasts by Western blot, viability, and migration assays. In the murine model of bleomycin-induced pulmonary fibrosis, the consequences of matriptase depletion, either by using the pharmacological inhibitor camostat mesilate (CM), or by genetic down-regulation using matriptase hypomorphic mice, were characterized by quantification of secreted collagen and immunostainings. MEASUREMENTS AND MAIN RESULTS: Matriptase expression and activity were up-regulated in IPF and bleomycin-induced pulmonary fibrosis. In cultured human pulmonary fibroblasts, matriptase expression was significantly induced by transforming growth factor-ß. Furthermore, matriptase elicited signaling via protease-activated receptor-2 (PAR-2), and promoted fibroblast activation, proliferation, and migration. In the experimental bleomycin model, matriptase depletion, by the pharmacological inhibitor CM or by genetic down-regulation, diminished lung injury, collagen production, and transforming growth factor-ß expression and signaling. CONCLUSIONS: These results implicate increased matriptase expression and activity in the pathogenesis of pulmonary fibrosis in human IPF and in an experimental mouse model. Overall, targeting matriptase, or treatment by CM, which is already in clinical use for other diseases, may represent potential therapies for IPF.

The protease inhibitor HAI-2, but not HAI-1, regulates matriptase activation and shedding through prostasin.

The membrane-anchored serine proteases, matriptase and prostasin, and the membrane-anchored serine protease inhibitors, hepatocyte growth factor activator inhibitor (HAI)-1 and HAI-2, are critical effectors of epithelial development and postnatal epithelial homeostasis. Matriptase and prostasin form a reciprocal zymogen activation complex that results in the formation of active matriptase and prostasin that are targets for inhibition by HAI-1 and HAI-2. Conflicting data, however, have accumulated as to the existence of auxiliary functions for both HAI-1 and HAI-2 in regulating the intracellular trafficking and activation of matriptase. In this study, we, therefore, used genetically engineered mice to determine the effect of ablation of endogenous HAI-1 and endogenous HAI-2 on endogenous matriptase expression, subcellular localization, and activation in polarized intestinal epithelial cells. Whereas ablation of HAI-1 did not affect matriptase in epithelial cells of the small or large intestine, ablation of HAI-2 resulted in the loss of matriptase from both tissues. Gene silencing studies in intestinal Caco-2 cell monolayers revealed that this loss of cell-associated matriptase was mechanistically linked to accelerated activation and shedding of the protease caused by loss of prostasin regulation by HAI-2. Taken together, these data indicate that HAI-1 regulates the activity of activated matriptase, whereas HAI-2 has an essential role in regulating prostasin-dependent matriptase zymogen activation.

Detection of active matriptase using a biotinylated chloromethyl ketone peptide.

Matriptase is a member of the family of type II transmembrane serine proteases that is essential for development and maintenance of several epithelial tissues. Matriptase is synthesized as a single-chain zymogen precursor that is processed into a two-chain disulfide-linked form dependent on its own catalytic activity leading to the hypothesis that matriptase functions at the pinnacle of several protease induced signal cascades. Matriptase is usually found in either its zymogen form or in a complex with its cognate inhibitor hepatocyte growth factor activator inhibitor 1 (HAI-1), whereas the active non-inhibited form has been difficult to detect. In this study, we have developed an assay to detect enzymatically active non-inhibitor-complexed matriptase by using a biotinylated peptide substrate-based chloromethyl ketone (CMK) inhibitor. Covalently CMK peptide-bound matriptase is detected by streptavidin pull-down and subsequent analysis by Western blotting. This study presents a novel assay for detection of enzymatically active matriptase in living human and murine cells. The assay can be applied to a variety of cell systems and species.

Expression and genetic loss of function analysis of the HAT/DESC cluster proteases TMPRSS11A and HAT.

Genome mining at the turn of the millennium uncovered a new family of type II transmembrane serine proteases (TTSPs) that comprises 17 members in humans and 19 in mice. TTSPs phylogenetically belong to one of four subfamilies: matriptase, hepsin/TMPRSS, corin and HAT/DESC. Whereas a wealth of information now has been gathered as to the physiological functions of members of the hepsin/TMPRSS, matriptase, and corin subfamilies of TTSPs, comparatively little is known about the functions of the HAT/DESC subfamily of proteases. Here we perform a combined expression and functional analysis of this TTSP subfamily. We show that the five human and seven murine HAT/DESC proteases are coordinately expressed, suggesting a level of functional redundancy. We also perform a comprehensive phenotypic analysis of mice deficient in two of the most widely expressed HAT/DESC proteases, TMPRSS11A and HAT, and show that the two proteases are dispensable for development, health, and long-term survival in the absence of external challenges or additional genetic deficits. Our comprehensive expression analysis and generation of TMPRSS11A- and HAT-deficient mutant mouse strains provide a valuable resource for the scientific community for further exploration of the HAT/DESC subfamily proteases in physiological and pathological processes.

Role for the actomyosin complex in regulated exocytosis revealed by intravital microscopy.

The regulation and the dynamics of membrane trafficking events have been studied primarily in in vitro models that often do not fully reflect the functional complexity found in a living multicellular organism. Here we used intravital microscopy in the salivary glands of live rodents to investigate regulated exocytosis, a fundamental process in all of the secretory organs. We found that ß-adrenergic stimulation elicits exocytosis of large secretory granules, which gradually collapse with the apical plasma membrane without any evidence of compound exocytosis, as was previously described. Furthermore, we show that the driving force required to complete the collapse of the granules is provided by the recruitment of F-actin and nonmuscle myosin II on the granule membranes that is triggered upon fusion with the plasma membrane. Our results provide information on the machinery controlling regulated secretion and show that intravital microscopy provides unique opportunities to address fundamental questions in cell biology under physiological conditions.

Matriptase initiates activation of epidermal pro-kallikrein and disease onset in a mouse model of Netherton syndrome.

Deficiency in the serine protease inhibitor LEKTI is the etiological origin of Netherton syndrome, which causes detachment of the stratum corneum and chronic inflammation. Here we show that the membrane protease matriptase initiates Netherton syndrome in a LEKTI-deficient mouse model by premature activation of a pro-kallikrein cascade. Auto-activation of pro-inflammatory pro-kallikrein-related peptidases that are associated with stratum corneum detachment was either low or undetectable, but they were efficiently activated by matriptase. Ablation of matriptase from LEKTI-deficient mice dampened inflammation, eliminated aberrant protease activity, prevented detachment of the stratum corneum, and improved the barrier function of the epidermis. These results uncover a pathogenic matriptase-pro-kallikrein pathway that could operate in several human skin and inflammatory diseases.