Department of Biochemistry, Universidade Federal de São Paulo, Rua Três de Maio, 100, 4a. andar, Biologia Molecular, São Paulo, SP, 04044-020, Brazil.
Department of Biochemistry, Faculdade de Medicina do ABC, Avenida Príncipe de Gales, 821, Bioquímica, Santo André, SP, 09060-650, Brazil.
Mol Biol Rep. 2021 Apr;48(4):3117-3125. doi: 10.1007/s11033-021-06348-3. Epub 2021 Apr 23.
Heparanase is an endo-beta-glucuronidase, the only enzyme in mammals capable of cleaving heparan sulfate/heparin chains from proteoglycans. The oligosaccharides generated by heparanase present extensive biological functions since such oligosaccharides interact with adhesion molecules, growth factors, angiogenic factors and cytokines, modulating cell proliferation, migration, inflammation, and carcinogenesis. However, the regulation of heparanase activity is not fully understood. It is known that heparanase is synthesized as an inactive 65 kDa isoform and that post-translation processing forms an active 50 kDa enzyme. In the present study, we are interested in investigating whether heparanase is regulated by its own substrate as observed with many other enzymes. Wild-type Chinese hamster (Cricetulus griséus) ovary cells (CHO-K1) were treated with different doses of heparin. Heparanase expression was analyzed by Real-time PCR and flow cytometry. Also, heparanase activity was measured. The heparanase activity assay was performed using a coated plate with biotinylated heparan sulfate. In the present assay, a competitive heparin inhibition scenario was set aside. Exogenous heparin trigged a cell signaling pathway that increased heparanase mRNA and protein levels. The Wnt/beta-catenin pathway, judged by TCF-driven luciferase activity, seems to be involved to enhance heparanase profile during treatment with exogenous heparin. Lithium chloride treatment, an activator of the Wnt/beta-catenin pathway, confirmed such mechanism of transduction in vivo using zebrafish embryos and in vitro using CHO-K1 cells. Taken together the results suggest that heparin modulates heparanase expression by Wnt/beta-catenin.
乙酰肝素酶是一种内-β-葡糖醛酸酶,是哺乳动物中唯一能够将糖胺聚糖/肝素链从蛋白聚糖中切割的酶。乙酰肝素酶产生的低聚糖具有广泛的生物学功能,因为这些低聚糖与粘附分子、生长因子、血管生成因子和细胞因子相互作用,调节细胞增殖、迁移、炎症和癌变。然而,乙酰肝素酶活性的调节机制尚不完全清楚。已知乙酰肝素酶最初合成时为无活性的 65 kDa 同工型,经翻译后加工形成有活性的 50 kDa 酶。本研究旨在探讨乙酰肝素酶是否像许多其他酶一样受其自身底物的调节。用不同剂量的肝素处理野生型中国仓鼠卵巢细胞(CHO-K1)。通过实时 PCR 和流式细胞术分析乙酰肝素酶的表达。同时,测量乙酰肝素酶的活性。乙酰肝素酶活性测定采用包被有生物素化硫酸乙酰肝素的平板进行。在本实验中,采用肝素竞争性抑制方案。外源性肝素触发细胞信号通路,增加乙酰肝素酶 mRNA 和蛋白水平。通过 TCF 驱动的荧光素酶活性判断,Wnt/β-catenin 途径似乎参与了外源性肝素处理过程中乙酰肝素酶谱的增强。用氯化锂处理(Wnt/β-catenin 途径的激活剂),通过斑马鱼胚胎体内实验和 CHO-K1 细胞体外实验证实了这种转导机制。综上所述,结果表明肝素通过 Wnt/β-catenin 调节乙酰肝素酶的表达。