Human CTSK(Cathepsin K) ELISA Kit

Objective: Evidence suggests that cathepsin S (CTSS), a potent mammalian elastase, participates in abdominal aortic aneurysm (AAA) formation. This study examines the hypothesis that pharmacological inhibition of CTSS with an alpha-ketoamide based compound 6r might suppress AAA in mice. Methods: Experimental study of the CaCl2 induced AAA model in B6 mice and angiotensin II (AngII) infused AAA model in ApoE(-/-) mice. The effects of intraperitoneal administration of 6r (25 mg/kg) and vehicle every three days since one day after AAA induction were evaluated at 28 days using CaCl2 induced (n = 12 per group) and AngII infused (n = 8 per group) models. Additionally, the effects of post-treatment with 6r and vehicle from seven days or 14 days after AAA induction were evaluated at 28 days using the CaCl2 induced model (n = 6 per group). Aortic samples were harvested for histological and biochemical analyses, including cathepsin levels, Verhoeff Van Gieson staining, TUNEL assay, and immunostaining for macrophages. Results: In the CaCl2 induced model, treatment with 6r suppressed aortic dilatation observed in vehicle treated controls (median: 0.58 vs. 0.92 mm; p < .001), along with reduced CTSS and cathepsin K (CTSK) levels (both p < .001), preserved elastin integrity (p < .001), fewer medial apoptotic cells (p = .012) and less macrophage infiltration (p = .041). In the Angll infused model, the aortic diameter was smaller in 6r treated mice than in vehicle treated controls (median: 0.95 vs. 1.84 mm; p = .047). The levels of CTSS (p < .001) and CTSK (p = .033) and the numbers of elastin breaks (p < .001), medial apoptotic cells (p < .001) and infiltrating macrophages (p = .030) were attenuated under 6r treatment. Finally, post-treatment with 6r from seven days (p = .046) or 14 days (p = .012) after AAA induction limited CaCl2 induced AAA. Conclusion: Pharmacological inhibition of CTSS by 6r suppresses AAA formation in mice. Also, post-treatment with 6r retards mouse AAA progression. These findings provide proof of concept validation for CTSS as a potential therapeutic target in AAA.

Background: Uranium is a naturally occurring radionuclide ubiquitously present in the environment. The skeleton is the main site of uranium long-term accumulation. While it has been shown that natural uranium is able to perturb bone metabolism through its chemical toxicity, its impact on bone resorption by osteoclasts has been poorly explored. Here, we examined for the first time in vitro effects of natural uranium on osteoclasts. Methods: The effects of uranium on the RAW 264.7 monocyte/macrophage mouse cell line and primary murine osteoclastic cells were characterized by biochemical, molecular and functional analyses. Results: We observed a cytotoxicity effect of uranium on osteoclast precursors. Uranium concentrations in the mu M range are able to inhibit osteoclast formation, mature osteoclast survival and mineral resorption but don't affect the expression of the osteoclast gene markers Nfatc1, Dc-stamp, Ctsk, Acp5, Atp6v0a3 or Atp6v0d2 in RAW 274.7 cells. Instead, we observed that uranium induces a dose-dependent accumulation of SQSTMl/p62 during osteoclastogenesis. Conclusions: We show here that uranium impairs osteoclast formation and function in vitro. The decrease in available precursor cells, as well as the reduced viability of mature osteoclasts appears to account for these effects of uranium. The SQSTMl/p62 level increase observed in response to uranium exposure is of particular interest since this protein is a known regulator of osteoclast formation. A tempting hypothesis discussed herein is that SQSTMl/p62 dysregulation contributes to uranium effects on osteoclastogenesis. General significance: We describe cellular and molecular effects of uranium that potentially affect bone homeostasis. (C) 2017 Elsevier B.V. All rights reserved.