Development of a therapeutic anti-marinobufagenin antibody

在PNx大鼠中，我们研究了3E9抗mbg单克隆抗体（mAb）对血压和心肌肥厚及纤维化的影响。在PNx大鼠中，血浆MBG水平升高4倍与高血压、心脏羰基化蛋白水平升高、心脏肥厚、心脏核转录因子（胶原合成的负调节因子Fli-1）表达减少以及胶原-1水平升高有关。PNx大鼠单次腹腔注射3E9 mAb，连续7天降低血压59 mmHg，并显著降低心脏重量和心脏氧化应激水平。这些作用与Fli-1表达的增加和心脏纤维化的减少有关。因此，在慢性肾衰竭中，MBG通过抑制Fli-1导致高血压并诱导心脏纤维化，这是一个潜在的治疗靶点。

In PNx rats, we studied effects of 3E9 anti-MBG monoclonal antibody (mAb) on BP and cardiac hypertrophy and fibrosis. In PNx rats, a four-fold elevation in plasma MBG levels was associated with hypertension, increased cardiac levels of carbonylated protein, cardiac hypertrophy, a reduction in cardiac expression of a nuclear transcription factor which is a negative regulator of collagen synthesis, Fli-1, and an increase in the levels of collagen-1. A single intraperitoneal administration of 3E9 mAb to PNx rats reduced BP by 59 mmHg for 7 days and significantly reduced cardiac weight and cardiac levels of oxidative stress. These effects were associated with an increase in the expression of Fli-1, and a reduction in cardiac fibrosis. Thus, in chronic renal failure MBG contributes to hypertension and induces cardiac fibrosis via suppression of Fli-1, representing a potential target for therapy. Because previously in uremic rats active immunization against MBG reduced cardiac fibrosis but minimally affected BP, we hypothesized that MBG induces vascular fibrosis via BP-independent mechanism. We determined BP, plasma and urinary MBG, aortic collagen-1, and vascular function in NaCl-loaded male Wistar rats with streptozotocin-induced type 2 diabetes mellitus (DM-NaCl) and in control animals. Isolated rings of thoracic aortae were tested for their responsiveness to sodium nitroprusside (SNP) following endothelin-1-induced constriction. DM-NaCl rats exhibited a 3.5-fold increase in MBG excretion and 2.5-fold increase in levels of collagen-1 in thoracic aortae without changes of BP. As compared to control, aortic rings from DM-NaCl rats exhibited impaired response to the relaxant effect of SNP. In vivo administration of 3E9 mAb to DM-NaCl rats did not affect BP, but reduced aortic levels of collagen-1, and restored sensitivity of aortic rings to SNP. Thus, MBG is capable to increase vascular stiffness without affecting BP.