A novel β-adrenergic response element regulates both basal and agonist-induced expression of cyclin-dependent kinase 1 gene in cardiac fibroblasts

Abstract

Cardiac fibrosis, a known risk factor for heart disease, is typically caused by uncontrolled proliferation of fibroblasts and excessive deposition of extracellular matrix proteins in the myocardium. Cyclin-dependent kinase 1 (CDK1) is involved in the control of G2/M transit phase of the cell cycle. Here, we showed that isoproterenol (ISO)-induced cardiac fibrosis is associated with increased levels of CDK1 exclusively in fibroblasts in the adult mouse heart. Treatment of primary embryonic ventricular cell cultures with ISO (a nonselective β-adrenergic receptor agonist) increased CDK1 protein expression in fibroblasts and promoted their cell cycle activity. Quantitative PCR analysis confirmed that ISO increases CDK1 transcription in a transient manner. Further, the ISO-responsive element was mapped to the proximal -100-bp sequence of the CDK1 promoter region using various 5'-flanking sequence deletion constructs. Sequence analysis of the -100-bp CDK1 minimal promoter region revealed two putative nuclear factor-Y (NF-Y) binding elements. Overexpression of the NF-YA subunit in primary ventricular cultures significantly increased the basal activation of the -100-bp CDK1 promoter construct but not the ISO-induced transcription of the minimal promoter construct. In contrast, dominant negative NF-YA expression decreased the basal activity of the minimal promoter construct and ISO treatment fully rescued the dominant negative effects. Furthermore, site-directed mutagenesis of the distal NF-Y binding site in the -100-bp CDK1 promoter region completely abolished both basal and ISO-induced promoter activation of the CDK1 gene. Collectively, our results raise an exciting possibility that targeting CDK1 or NF-Y in the diseased heart may inhibit fibrosis and subsequently confer cardioprotection.

Imatinib attenuates cardiac fibrosis by inhibiting platelet-derived growth factor receptors activation in isoproterenol induced model

“…The vehicle group was treated with PBS. Cardiac fibrosis was induced by subcutaneous ISO injection daily (20 mg/kg/d for 7 days) [24–26], and/or IMA (40 mg/kg/d for 7 days) [27, 28] was administered by intraperitoneal injection daily. After 7 days, animal echocardiography was used to preliminarily evaluate the success of the cardiac fibrosis model.…”

Critical effects of long non-coding RNA on fibrosis diseases

“…Cardiac fibrosis is a major factor in the progression of myocardial infarction and heart failure, 48 , 49 , 50 which is characterized by an excessive deposition of ECM proteins that impair organ function. 51 , 52 , 53 Cardiac fibroblasts (CFs) are primarily responsible for the homeostatic maintenance of tissue ECM, particularly healing after injury. 54 , 55 , 56 , 57 Activated fibroblasts exhibit increased protein synthesis, including collagens, other ECM proteins, certain cytokines and α-SMA (a contractile protein and marker of profibrogenic CF activation).…”

ANO1 inhibits cardiac fibrosis after myocardial infraction via TGF-β/smad3 pathway

“…Cardiac fibroblasts, making up more than 90% of the non-myocytes, play a major role in normal cardiac function and cardiac fibrosis 4–6 . In typical cardiac fibrosis, exessive proliferation of fibroblasts and deposition of extracellular matrix (ECM) proteins are stimulated by cardiac fibroblasts in the myocardium 7–9 . Cardiac fibrosis is a common pathological hallmark of many heart diseases including acute and chronic cardiovascular disorders, and contributes to systolic and diastolic dysfunction in many cases 10 .…”