OBJECTIVETo investigate the interaction between myocardial norepinephrine (NET) and protein interacting with kinase Cα (PICK1), and examine the myocardial expression pattern of NET and PICK1 in mice with adriamycin-induced congestive heart failure.

METHODS(1) Cellular experiments: 293T cells were transfected with NET, GFP-PICK1, NET+GFP-PICK1 or NET+GFP-PICK1(KD-AA), respectively. Immunofluorescence staining was performed 48 h after the transfection. (2) Animal experiments: 40 male C57BL/6J mice were divided into control group and adriamycin group (intraperitoneal injection of 2 mg/kg adriamycin with a cumulative amount of 22 mg/kg). The myocardial mRNA and protein expression level of NET, PICK1 and adrenergic receptor (β1-AR) were detected by real-time PCR and Western blot after 10 weeks.

RESULTS(1) PICK1 mediates the intracellular trafficking of NET. (2) Compared to controls, cardiac mRNA expression of NET remained unchanged, but PICK1 and β1-AR mRNA level were significantly reduced in the heart failure mice. (3) Myocardial NET protein expression level was significantly reduced, whereas tyrosine hydroxylase (TH) protein expression was significantly upregulated in heart failure mice. (4) The myocardial density of sympathetic nerve fibers remained unchanged in heart failure mice.

CONCLUSIONSCardiac expression of NET and PICK1 are down-regulated in heart failure mice. Reduced PICK1-mediated intracellular trafficking of NET may be involved in the impairment of NET function in this congestive heart failure mice model.