microRNA-221 Inhibits Latent TGF-β1 Activation through Targeting Thrombospondin-1 to Attenuate Kidney Failure-Induced Cardiac Fibrosis

Abstract

Kidney failure (KF) is associated with cardiac fibrosis and significantly increased mortality in heart failure. Thrombospondin-1 (TSP1), a key regulator of latent transforming growth factor-β1 (L-TGF-β1) activation, is a predicted target of miR-221. We hypothesized miR-221 attenuates severe KF-associated cardiac fibrosis via targeting of Thbs1 with subsequent inhibition of L-TGF-β1 activation. Rat cardiac fibroblasts (cFB) were isolated and transfected with microRNA-221 (miR-221) mimics or mimic control (miR-221 and MC) with or without exposure to L-TGF-β1. We demonstrate miR-221 downregulates Thbs1 via direct 3′ untranslated region (3′ UTR) targeting with consequent inhibition of L-TGF-β1 activation in cFB as proven by the significant reduction of myofibroblast activation, collagen secretion, TGF-β1 signaling, TSP1 secretion, and TGF-β1 bioactivity measured by Pai1 promoter reporter. The 5/6 nephrectomy (Nx) model of cardiac fibrosis was used to test the in vivo therapeutic efficacy of miR-221 (i.v. 1 mg/kg ×3). miR-221 significantly inhibited Nx-induced upregulation of TSP1 and p-SMAD3 in the heart at day-7 and reduced cardiac fibrosis (picro-sirius), improved cardiac function (±dP/dt), and improved 8-week survival rate (60% versus 36%; p = 0.038). miR-221 mimic treatment improved survival and reduced cardiac fibrosis in a model of severe KF. miR-221 is a therapeutic target to address cardiac fibrosis originating from renal disease and other causes.

Dysregulation of MicroRNAs in Hypertrophy and Ossification of Ligamentum Flavum: New Advances, Challenges, and Potential Directions

“…To sum up, downregulated miR-221 might promote LF hypertrophy through inducing collagens I and III expression via targeting TIMP-2. A growing body of evidence showed that miR-221 was one of fibrosis-associated miRNAs and played important parts in the occurrence and development of fibrotic diseases, such as liver fibrosis (Tsay et al, 2019), cardiac fibrosis (Zhou et al, 2020), and renal fibrosis (Morinaga et al, 2016). Therefore, future researches are expected to conduct a further exploration of miR-221 as the potential therapeutic target for HLF.…”

Association of atrial arrhythmias with thrombospondin-1 in patients with acute myocardial infarction

“…Procter et al [ 22 ] also found platelet hyperaggregability, induced by the release of TSP-1 from platelet α-granules, may diminish nitric oxide signaling, thus promoting inflammation. Recently, Zhou et al [ 23 ] reported that microRNA-221 could inhibit latent TGF-β1 activation by targeting TSP-1 to attenuate cardiac fibrosis, which could be a possible upstream treatment of AA.…”

MicroRNA-Related Strategies to Improve Cardiac Function in Heart Failure

“…Zhou et al (114) proved that miR-221 inhibits the activation of L-TGF-β1 by directly targeting THBS1, thus mitigating cardiac fibrosis and improving cardiac function. Similarly, miR-221 mimics transfected into rat cardiac fibroblasts induced by kidney failure resulted in reduction of cardiac fibrosis.…”

“…Similarly, miR-221 mimics transfected into rat cardiac fibroblasts induced by kidney failure resulted in reduction of cardiac fibrosis. Therefore, miR-221 mimics are a promising therapeutic target in cardiac fibrosis (114).…”