INTRODUCTION: The aging process is intricately linked to alterations in cellular and tissue structures, with the respiratory system being particularly susceptible to age-related changes. Therefore, this study aimed to profile the activity of proteases using activity-based probes in lung tissues of old and young rats, focusing on the expression levels of different, in particular cathepsins G and X and matrix Metalloproteinases (MMPs). Additionally, the impact on extracellular matrix (ECM) components, particularly fibronectin, in relation to age-related histological and ultrastructural changes in lung tissues was investigated. MATERIALS AND METHODS: Lung tissues from old and young rats were subjected to activity-based probe profiling to assess the activity of different proteases. Expression levels of cathepsins G and X were quantified, and zymography was performed to evaluate matrix metalloproteinases activity. Furthermore, ECM components, specifically fibronectin, were examined for signs of degradation in the old lung tissues compared to the young ones. Moreover, histological, immunohistochemical and ultrastructural assessments of old and young lung tissue were also conducted. RESULTS: Our results showed that the expression levels of cathepsins G and X were notably higher in old rat lung tissues in contrast to those in young rat lung tissues. Zymography analysis revealed elevated MMP activity in the old lung tissues compared to the young ones. Particularly, significant degradation of fibronectin, an essential ECM component, was observed in the old lung tissues. Numerous histological and ultrastructural alterations were observed in old lung tissues compared to young lung tissues. DISCUSSION AND CONCLUSION: The findings indicate an age-related upregulation of cathepsins G and X along with heightened MMP activity in old rat lung tissues, potentially contributing to the degradation of fibronectin within the ECM. These alterations highlight potential mechanisms underlying age-associated changes in lung tissue integrity and provide insights into protease-mediated ECM remodeling in the context of aging lungs.

• MeSH
• extracelulární matrix metabolismus   ultrastruktura   MeSH
• fibronektiny * metabolismus   MeSH
• kathepsin G metabolismus   MeSH
• krysa rodu rattus MeSH
• lyzozomy ultrastruktura   metabolismus   MeSH
• matrixové metaloproteinasy metabolismus   MeSH
• plíce * ultrastruktura   metabolismus   MeSH
• proteasy metabolismus   MeSH
• stárnutí * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Platelet aggregation and acute inflammation are key processes in vertebrate defense to a skin injury. Recent studies uncovered the mediation of 2 serine proteases, cathepsin G and chymase, in both mechanisms. Working with a mouse model of acute inflammation, we revealed that an exogenous salivary protein of Ixodes ricinus, the vector of Lyme disease pathogens in Europe, extensively inhibits edema formation and influx of neutrophils in the inflamed tissue. We named this tick salivary gland secreted effector as I ricinus serpin-2 (IRS-2), and we show that it primarily inhibits cathepsin G and chymase, while in higher molar excess, it affects thrombin activity as well. The inhibitory specificity was explained using the crystal structure, determined at a resolution of 1.8 Å. Moreover, we disclosed the ability of IRS-2 to inhibit cathepsin G-induced and thrombin-induced platelet aggregation. For the first time, an ectoparasite protein is shown to exhibit such pharmacological effects and target specificity. The stringent specificity and biological activities of IRS-2 combined with the knowledge of its structure can be the basis for the development of future pharmaceutical applications.

• MeSH
• agregace trombocytů genetika   imunologie   MeSH
• chymasy imunologie   metabolismus   MeSH
• exprese genu MeSH
• hmyzí proteiny genetika   imunologie   metabolismus   MeSH
• kathepsin G imunologie   metabolismus   MeSH
• klíště genetika   imunologie   metabolismus   MeSH
• krystalizace MeSH
• kvarterní struktura proteinů MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• molekulární sekvence - údaje MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• sekvence aminokyselin MeSH
• sekvenční analýza proteinů MeSH
• serpiny genetika   imunologie   metabolismus   MeSH
• slinné proteiny a peptidy genetika   imunologie   metabolismus   MeSH
• zánět imunologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH