Project description:Myocardial hypertrophy is an adaptive response to hemodynamic demands. Although angiogenesis is critical to support the increase in heart mass with matching blood supply, it may also promote a hypertrophic response. Previously, we showed that cardiac angiogenesis induced by placental growth factor (PlGF), promotes myocardial hypertrophy through the paracrine action of endothelium-derived NO, which triggers the degradation of regulator of G protein signaling 4 (RGS4) to activate the Akt/mTORC1 pathways in cardiomyocytes. Here, we investigated whether miRNAs contribute to the development of hypertrophic response associated with myocardial angiogenesis. We show that miR-182 is upregulated concurrently with the development of hypertrophy in PlGF mice, but not when hypertrophy was blocked by concomitant expression of PlGF and RGS4, or by PlGF expression in eNOS(-/-) mice. Anti-miR-182 treatment inhibits the hypertrophic response and prevents the Akt/mTORC1 activation in PlGF mice and NO-treated cardiomyocytes. miR-182 reduces the expression of Bcat2, Foxo3 and Adcy6 to regulate the hypertrophic response in PlGF mice. Particularly, depletion of Bcat2, identified as a new miR-182 target, promotes Akt(Ser473)/p70-S6K(Thr389) phosphorylation and cardiomyocyte hypertrophy. LV pressure overload did not upregulate miR-182. Thus, miR-182 is a novel target of endothelial-cardiomyocyte crosstalk and plays an important role in the angiogenesis induced-hypertrophic response.
Project description:Angiogenesis induced by placental growth factor (PlGF) in heart promotes myocardial hypertrophy through the paracrine action of endothelium-derived nitric oxide which triggers the degradation of RGS4 and subsequent activation of the Akt/mTORC1 pathway in cardiomyocytes. However, whether alterations in miRNAs contribute to the development of hypertrophy is largely undetermined. We found that miR-182 contributed to the hypertrophic response and activation of the Akt/mTORC1 pathway by suppressing the expression of Bcat2, Pink1, Adcy6, Foxo3. The expression of miRNAs and the effects of anti-miRs were investigated in the mouse model of myocardial angiogenesis induced by conditional, cardiac specific expression of PlGF. We also induced angiogenesis, but blocked hypertrophy by concomitant expression of PlGF and RGS4 (PlGF/RGS4 mice). Microarray profiling of miRNAs in LV myocardium was determined after 3 and 6 weeks of transgene expression.
Project description:Angiogenesis induced by placental growth factor (PlGF) in heart promotes myocardial hypertrophy through the paracrine action of endothelium-derived nitric oxide which triggers the degradation of RGS4 and subsequent the activation of Akt/mTORC1 pathway in cardiomyocytes. However, whether alterations in miRNAs contribute to the development of hypertrophy is largely undetermined. We found that miR-182 contributed to the hypertrophic response and activation of Akt/mTORC1 pathway by suppressing the expression of Bcat2, Pink1, Adcy6, Foxo3. miR-182 targeted genes were investigated in the mouse model of myocardial angiogenesis induced by conditional, cardiac specific expression of PlGF. We also induced angiogenesis, but blocked hypertrophy by concomitant expression of PlGF and RGS4 (PlGF/RGS4 mice). The mRNA expression profiling in PlGF and PlGF/RGS4 mice were assessed after 6 weeks of transgene expression, concurent with the development of myocardial hypertrophy.
Project description:Angiogenesis induced by placental growth factor (PlGF) in heart promotes myocardial hypertrophy through the paracrine action of endothelium-derived nitric oxide which triggers the degradation of RGS4 and subsequent the activation of Akt/mTORC1 pathway in cardiomyocytes. However, whether alterations in miRNAs contribute to the development of hypertrophy is largely undetermined. We found that miR-182 contributed to the hypertrophic response and activation of Akt/mTORC1 pathway by suppressing the expression of Bcat2, Pink1, Adcy6, Foxo3.
Project description:Angiogenesis induced by placental growth factor (PlGF) in heart promotes myocardial hypertrophy through the paracrine action of endothelium-derived nitric oxide which triggers the degradation of RGS4 and subsequent activation of the Akt/mTORC1 pathway in cardiomyocytes. However, whether alterations in miRNAs contribute to the development of hypertrophy is largely undetermined. We found that miR-182 contributed to the hypertrophic response and activation of the Akt/mTORC1 pathway by suppressing the expression of Bcat2, Pink1, Adcy6, Foxo3.
Project description:Intermittent hypoxia (IH) is a feature of obstructive sleep apnea (OSA), a condition highly associated with hypertension-related cardiovascular diseases. Repeated episodes of IH contribute to imbalance of angiogenic growth factors in the hypertrophic heart, which is key in the progression of cardiovascular complications. In particular, the interaction between vascular endothelial growth factor (VEGF) and the kallikrein-kinin system (KKS) is essential for promoting angiogenesis. However, researchers have yet to investigate experimental models of IH that reproduce OSA, myocardial angiogenesis, and expression of KKS components. We examined temporal changes in cardiac angiogenesis in a mouse IH model. Adult male C57BI/6 J mice were implanted with Matrigel plugs and subjected to IH for 1-5 weeks with subsequent weekly histological evaluation of vascularization. Expression of VEGF and KKS components was also evaluated. After 3 weeks, in vivo myocardial angiogenesis and capillary density were decreased, accompanied by a late increase of VEGF and its type 2 receptor. Furthermore, IH increased left ventricular myocardium expression of the B2 bradykinin receptor, while reducing mRNA levels of B1 receptor. These results suggest that in IH, an unexpected response of the VEGF and KKS systems could explain the reduced capillary density and impaired angiogenesis in the hypoxic heart, with potential implications in hypertrophic heart malfunction.
Project description:BackgroundHypoxia is a common feature of solid tumors, including HCC. And hypoxia has been reported to play an important role in HCC progression. However, the potential mechanism of miRNAs in hypoxia mediating HCC progression still remains unclear.MethodsThe HCC cells were cultured in the atmosphere of 1 % oxygen to induce hypoxia. The microRNA microarray was employed to search for the hypoxia-inducible miRNAs. RT-PCR, western blot and immunohistochemistry were used to detect the RNA and protein levels. HUVEC were applied to explore the angiogenesis level.ResultsWe found that miR-182 was upregulated in the hypoxia-based microarray. We then revealed that miR-182 was also significantly increased in the HCC tissues compared to the corresponding normal tissues. In vitro capilliary tube formation assays showed that the miR-182 promoted angiogenesis. RASA1 was demonstrated as the direct target of miR-182. In addition, the suppression of RASA1 phenocopied the pro-angiogenesis effects of miR-182. Besides, RASA1 was also decreased in the hypoxia HCC cells while the inhibition of miR-182 partially restored the level of RASA1.ConclusionsOur data showed that hypoxia regulated the expression of miR-182 and RASA1 to promote HCC angiogenesis.
Project description:Increased osteoclastogenesis is responsible for osteolysis, which is a severe consequence of inflammatory diseases associated with bone destruction, such as rheumatoid arthritis and periodontitis. The mechanisms that limit osteoclastogenesis under inflammatory conditions are largely unknown. We previously identified transcription factor RBP-J as a key negative regulator that restrains TNF-?-induced osteoclastogenesis and inflammatory bone resorption. In this study, we tested whether RBP-J suppresses inflammatory osteoclastogenesis by regulating the expression of microRNAs (miRNAs) important for this process. Using high-throughput sequencing of miRNAs, we obtained the first, to our knowledge, genome-wide profile of miRNA expression induced by TNF-? in mouse bone marrow-derived macrophages/osteoclast precursors during inflammatory osteoclastogenesis. Furthermore, we identified miR-182 as a novel miRNA that promotes inflammatory osteoclastogenesis driven by TNF-? and whose expression is suppressed by RBP-J. Downregulation of miR-182 dramatically suppressed the enhanced osteoclastogenesis program induced by TNF-? in RBP-J-deficient cells. Complementary loss- and gain-of-function approaches showed that miR-182 is a positive regulator of osteoclastogenic transcription factors NFATc1 and B lymphocyte-induced maturation protein-1. Moreover, we identified that direct miR-182 targets, Foxo3 and Maml1, play important inhibitory roles in TNF-?-mediated osteoclastogenesis. Thus, RBP-J-regulated miR-182 promotes TNF-?-induced osteoclastogenesis via inhibition of Foxo3 and Maml1. Suppression of miR-182 by RBP-J serves as an important mechanism that restrains TNF-?-induced osteoclastogenesis. Our results provide a novel miRNA-mediated mechanism by which RBP-J inhibits osteoclastogenesis and suggest that targeting of the newly described RBP-J-miR-182-Foxo3/Maml1 axis may represent an effective therapeutic approach to suppress inflammatory osteoclastogenesis and bone resorption.