Therapeutic impact of follistatin-like 1 on myocardial ischemic injury in preclinical models.
ABSTRACT: Acute coronary syndrome is a leading cause of death in developed countries. Follistatin-like 1 (FSTL1) is a myocyte-derived secreted protein that is upregulated in the heart in response to ischemic insult. Here, we investigated the therapeutic impact of FSTL1 on acute cardiac injury in small and large preclinical animal models of ischemia/reperfusion and dissected its molecular mechanism.Administration of human FSTL1 protein significantly attenuated myocardial infarct size in a mouse or pig model of ischemia/reperfusion, which was associated with a reduction of apoptosis and inflammatory responses in the ischemic heart. Administration of FSTL1 enhanced the phosphorylation of AMP-activated protein kinase in the ischemia/reperfusion-injured heart. In cultured cardiac myocytes, FSTL1 suppressed apoptosis in response to hypoxia/reoxygenation and lipopolysaccharide-stimulated expression of proinflammatory genes through its ability to activate AMP-activated protein kinase. Ischemia/reperfusion led to enhancement of bone morphogenetic protein-4 expression and Smad1/5/8 phosphorylation in the heart, and FSTL1 suppressed the increased phosphorylation of Smad1/5/8 in ischemic myocardium. Treating cardiac myocytes with FSTL1 abolished the bone morphogenetic protein-4-stimulated increase in apoptosis, Smad1/5/8 phosphorylation, and proinflammatory gene expression. In cultured macrophages, FSTL1 diminished lipopolysaccharide-stimulated expression of proinflammatory genes via activation of AMP-activated protein kinase and abolished bone morphogenetic protein-4-dependent induction of proinflammatory mediators.Our data indicate that FSTL1 can prevent myocardial ischemia/reperfusion injury by inhibiting apoptosis and inflammatory response through modulation of AMP-activated protein kinase- and bone morphogenetic protein-4-dependent mechanisms, suggesting that FSTL1 could represent a novel therapeutic target for post-myocardial infarction, acute coronary syndrome.
Project description:Stroke results in brain tissue damage from ischemia and oxidative stress. Molecular regulators of the protective versus deleterious cellular responses after cerebral ischemia remain to be identified. Here, we show that deletion of Smad1, a conserved transcription factor that mediates canonical bone morphogenetic protein (BMP) signaling, results in neuroprotection in an ischemia-reperfusion (I/R) stroke model. Uninjured mice with conditional deletion of Smad1 in the CNS (Smad1 cKO) displayed upregulation of the reactive astrocyte marker GFAP and hypertrophic morphological changes in astrocytes compared to littermate controls. Additionally, cultured Smad1(-/-) astrocytes exhibited an enhanced antioxidant capacity. When subjected to I/R injury by transient middle cerebral artery occlusion (tMCAO), Smad1 cKO mice showed enhanced neuronal survival and improved neurological recovery at 7 days post-stroke. This neuroprotective phenotype is associated with attenuated reactive astrocytosis and neuroinflammation, along with reductions in oxidative stress, p53 induction, and apoptosis. Our data suggest that Smad1-mediated signaling pathway is involved in stroke pathophysiology and may present a new potential target for stroke therapy.
Project description:The Akt protein kinase is an important mediator of cardiac myocyte growth and survival. To identify factors with novel therapeutic applications in cardiac diseases, we focused on the identification of factors secreted from Akt1-activated cells that have cardioprotective effects through autocrine/paracrine mechanisms.Using an inducible Akt1 transgenic mouse model, we have found that follistatin-like 1 (Fstl1) protein and transcript expression are increased 4.0- and 2.0-fold, respectively, by Akt activation in the heart (P<0.05). Fstl1 transcript was also upregulated in response to myocardial stresses including transverse aortic constriction, ischemia/reperfusion injury, and myocardial infarction. Adenovirus-mediated overexpression of Fstl1 protected cultured neonatal rat ventricular myocytes from hypoxia/reoxygenation-induced apoptosis (P<0.01), and this protective effect was dependent on the upregulation of both Akt and ERK activities. Conversely, knockdown of Fstl1 in cardiac myocytes decreased basal Akt signaling and increased the frequency of apoptotic death in vitro (P<0.01). The intravenous administration of an adenoviral encoding Fstl1 to mice resulted in a 66.0% reduction in myocardial infarct size after ischemia/reperfusion injury that was accompanied by a 70.9% reduction in apoptosis in the heart (P<0.01).These results indicate that Fstl1 is a cardiac-secreted factor that functions as an antiapoptotic protein. Fstl1 could play a role in myocardial maintenance and repair in response to harmful stimuli.
Project description:Lung morphogenesis is a well orchestrated, tightly regulated process through several molecular pathways, including TGF-?/bone morphogenetic protein (BMP) signaling. Alteration of these signaling pathways leads to lung malformation. We investigated the role of Follistatin-like 1 (Fstl1), a secreted follistatin-module-containing glycoprotein, in lung development. Deletion of Fstl1 in mice led to postnatal lethality as a result of respiratory failure. Analysis of the mutant phenotype showed that Fstl1 is essential for tracheal cartilage formation and alveolar maturation. Deletion of the Fstl1 gene resulted in malformed tracheal rings manifested as discontinued rings and reduced ring number. Fstl1-deficient mice displayed septal hypercellularity and end-expiratory atelectasis, which were associated with impaired differentiation of distal alveolar epithelial cells and insufficient production of mature surfactant proteins. Mechanistically, Fstl1 interacted directly with BMP4, negatively regulated BMP4/Smad1/5/8 signaling, and inhibited BMP4-induced surfactant gene expression. Reducing BMP signaling activity by Noggin rescued pulmonary atelectasis of Fstl1-deficient mice. Therefore, we provide in vivo and in vitro evidence to demonstrate that Fstl1 modulates lung development and alveolar maturation, in part, through BMP4 signaling.
Project description:Heart disease contributes to the progression of CKD. Heart tissue produces a number of secreted proteins, also known as cardiokines, which participate in intercellular and intertissue communication. We recently reported that follistatin-like 1 (Fstl1) functions as a cardiokine with cardioprotective properties. Here, we investigated the role of cardiac Fstl1 in renal injury after subtotal nephrectomy. Cardiac-specific Fstl1-deficient (cFstl1-KO) mice and wild-type mice were subjected to subtotal (5/6) nephrectomy. cFstl1-KO mice showed exacerbation of urinary albumin excretion, glomerular hypertrophy, and tubulointerstitial fibrosis after subtotal renal ablation compared with wild-type mice. cFstl1-KO mice also exhibited increased mRNA levels of proinflammatory cytokines, including TNF-? and IL-6, NADPH oxidase components, and fibrotic mediators, in the remnant kidney. Conversely, systemic administration of adenoviral vectors expressing Fstl1 (Ad-Fstl1) to wild-type mice with subtotal nephrectomy led to amelioration of albuminuria, glomerular hypertrophy, and tubulointerstitial fibrosis, accompanied by reduced expression of proinflammatory mediators, NADPH oxidase components, and fibrotic markers in the remnant kidney. In cultured human mesangial cells, treatment with recombinant FSTL1 attenuated TNF-?-stimulated expression of proinflammatory cytokines. Treatment of mesangial cells with FSTL1 augmented the phosphorylation of AMP-activated protein kinase (AMPK), and inhibition of AMPK activation abrogated the anti-inflammatory effects of FSTL1. These data suggest that Fstl1 functions in cardiorenal communication and that the lack of Fstl1 production by myocytes promotes glomerular and tubulointerstitial damage in the kidney.
Project description:Bone morphogenetic protein (BMP) signaling regulates vascular smooth muscle maturation, endothelial cell proliferation, and tube formation. The endogenous BMP antagonist Follistatin-like 1 (Fstl1) is highly expressed in pulmonary vascular endothelium of the developing mouse lung, suggesting a role in pulmonary vascular formation and vascular homeostasis. The aim of this study was to investigate the role of Fstl1 in the pulmonary vascular endothelium. To this aim, Fstl1 was conditionally deleted from endothelial and endothelial-derived cells using Tie2-cre driven Fstl1-KO mice (Fstl1-eKO mice). Endothelial-specific Fstl1 deletion was postnatally lethal, as ?70% of Fstl1-eKO mice died at three weeks after birth. Deletion of Fstl1 from endothelium resulted in a reduction of right ventricular output at three weeks after birth compared with controls. This was associated with pulmonary vascular remodeling, as the percentage of actin-positive small pulmonary vessels was increased at three weeks in Fstl1-eKO mice compared with controls. Endothelial deletion of Fstl1 resulted in activation of Smad1/5/8 signaling and increased BMP/Smad-regulated gene expression of Jagged1, Endoglin, and Gata2 at one week after birth compared with controls. In addition, potent vasoconstrictor Endothelin-1, the expression of which is driven by Gata2, was increased in expression, both on the mRNA and protein levels, at one week after birth compared with controls. At three weeks, Jagged1 was reduced in the Fstl1-eKO mice whereas Endoglin and Endothelin-1 were unchanged. In conclusion, loss of endothelial Fstl1 in the lung is associated with elevated BMP-regulated genes, impaired small pulmonary vascular remodeling, and decreased right ventricular output.
Project description:Here, we aimed to clarify the role of CXC chemokine receptor (CXCR) 2 in macrophage migration-inhibitory factor (MIF)-mediated effects after myocardial ischemia and reperfusion. As a pleiotropic chemokine-like cytokine, MIF has been identified to activate multiple receptors, including CD74 and CXCR2. In models of myocardial infarction, MIF exerts both proinflammatory effects and protective effects in cardiomyocytes. Similarly, CXCR2 displays opposing effects in resident versus circulating cells.Using bone marrow transplantation, we generated chimeric mice with Cxcr2(-/-) bone marrow-derived inflammatory cells and wild-type (wt) resident cells (wt/Cxcr2(-/-)), Cxcr2(-/-) cardiomyocytes and wt bone marrow-derived cells (Cxcr2(-/-)/wt), and wt controls reconstituted with wt bone marrow (wt/wt). All groups were treated with anti-MIF or isotype control antibody before they underwent myocardial ischemia and reperfusion. Blocking MIF increased infarction size and impaired cardiac function in wt/wt and wt/CXCR2(-/-) mice but ameliorated functional parameters in Cxcr2(-/-)/wt mice, as analyzed by echocardiography and Langendorff perfusion. Neutrophil infiltration and angiogenesis were unaltered by MIF blockade or Cxcr2 deficiency. Monocyte infiltration was blunted in wt/Cxcr2(-/-) mice and reduced by MIF blockade in wt/wt and Cxcr2(-/-)/wt mice. Furthermore, MIF blockade attenuated collagen content in all groups in a CXCR2-independent manner.The compartmentalized and opposing effects of MIF after myocardial ischemia and reperfusion are largely mediated by CXCR2. Although MIF confers protective effects by improving myocardial healing and function through CXCR2 in resident cells, thereby complementing paracrine effects through CD74/AMP-activated protein kinase, it exerts detrimental effects on CXCR2-bearing inflammatory cells by increasing monocyte infiltration and impairing heart function. These dichotomous findings should be considered when developing novel therapeutic strategies to treat myocardial infarction.
Project description:A longevity gene, sirtuin 1 (SIRT1) and energy sensor AMP-activated protein kinase (AMPK) have common activators such as caloric restriction, oxidative stress and exercise.The objective is to characterize the role of cardiomyocyte SIRT1 in age-related impaired ischemic AMPK activation and increased susceptibility to ischemic insults. Overall design: we want to compared wt and sirt1 ko mice heart, both basal and ischemia /reperfusion condition List is : 1. WT BASAL; 2. WT ISCHEMIA/REPERFUSION; 3. wt cardiomyocytes; 4. SIRT1 KO cardiomyocytes; 5. SIRT1 KO BASAL; 6. SIRT1 KO ISCHEMIA/REPERFUSION
Project description:Follistatin-like 1 (FSTL1) is a secreted bone morphogenetic protein (BMP) antagonist, and it plays a crucial role in normal lung development. Deletion of Fstl1 leads to postnatal death in mice due to respiratory failure. To further explore the role of FSTL1 in mouse lung development, we created a transgene SFTPC-Fstl1 allele mouse displaying significant epithelial overexpression of Fstl1 in all stages of lung development. However, epithelial overexpression of Fstl1 did not alter lung morphogenesis, epithelial differentiation and lung function. Moreover, we found that FSTL1 function was blocked by the epithelial polarization, which was reflected by the remarkable apical secretion of FSTL1 and the basolateral BMP signaling. Taken together, this study demonstrates that tightly spatial interaction of FSTL1 and BMP signaling plays an essential role in lung development.
Project description:Progressive tissue fibrosis is a cause of major morbidity and mortality. Pulmonary fibrosis is an epithelial-mesenchymal disorder in which TGF-?1 plays a central role in pathogenesis. Here we show that follistatin-like 1 (FSTL1) differentially regulates TGF-? and bone morphogenetic protein signaling, leading to epithelial injury and fibroblast activation. Haplodeletion of Fstl1 in mice or blockage of FSTL1 with a neutralizing antibody in mice reduced bleomycin-induced fibrosis in vivo. Fstl1 is induced in response to lung injury and promotes the accumulation of myofibroblasts and subsequent fibrosis. These data suggest that Fstl1 may serve as a novel therapeutic target for treatment of progressive lung fibrosis.
Project description:Factors secreted by the heart, referred to as "cardiokines," have diverse actions in the maintenance of cardiac homeostasis and remodeling. Follistatin-like 1 (Fstl1) is a secreted glycoprotein expressed in the adult heart and is induced in response to injurious conditions that promote myocardial hypertrophy and heart failure. The aim of this study was to investigate the role of cardiac Fstl1 in the remodeling response to pressure overload. Cardiac myocyte-specific Fstl1-KO mice were constructed and subjected to pressure overload induced by transverse aortic constriction (TAC). Although Fstl1-KO mice displayed no detectable baseline phenotype, TAC led to enhanced cardiac hypertrophic growth and a pronounced loss in ventricular performance by 4 wk compared with control mice. Conversely, mice that acutely or chronically overexpressed Fstl1 were resistant to pressure overload-induced hypertrophy and cardiac failure. Fstl1-deficient mice displayed a reduction in TAC-induced AMP-activated protein kinase (AMPK) activation in heart, whereas Fstl1 overexpression led to increased myocardial AMPK activation under these conditions. In cultured neonatal cardiomyocytes, administration of Fstl1 promoted AMPK activation and antagonized phenylephrine-induced hypertrophy. Inhibition of AMPK attenuated the antihypertrophic effect of Fstl1 treatment. These results document that cardiac Fstl1 functions as an autocrine/paracrine regulatory factor that antagonizes myocyte hypertrophic growth and the loss of ventricular performance in response to pressure overload, possibly through a mechanism involving the activation of the AMPK signaling axis.