Haibo Song

Irisin promotes human umbilical vein endothelial cell proliferation through the ERK signaling pathway and partly suppresses high glucose-induced apoptosis.

Irisin is a newly discovered myokine that links exercise with metabolic homeostasis. It is involved in modest weight loss and improves glucose intolerance. However, the direct effects and mechanisms of irisin on vascular endothelial cells (ECs) are not fully understood. In the current study, we demonstrated that irisin promoted Human Umbilical Vein Endothelial Cell (HUVEC) proliferation. It was further demonstrated that this pro-proliferation effect was mediated by irisin-induced activation of extracellular signal–related kinase (ERK) signaling pathways. Inhibition of ERK signaling with U0126 decreased the pro-proliferation effect of irisin on HUVECs. It was also demonstrated that irisin reduced high glucose-induced apoptosis by up-regulating Bcl-2 expression and down-regulating Bax, Caspase-9 and Caspase-3 expression. In summary, these results suggested that irisin plays a novel role in sustaining endothelial homeostasis by promoting HUVEC proliferation via the ERK signaling pathway and protects the cell from high glucose-induced apoptosis by regulating Bcl-2,Bax and Caspase expression.

Irisin Induces Angiogenesis in Human Umbilical Vein Endothelial Cells In Vitro and in Zebrafish Embryos In Vivo via Activation of the ERK Signaling Pathway.

As a link between exercise and metabolism, irisin is assumed to be involved in increased total body energy expenditure, reduced body weight, and increased insulin sensitivity. Although our recent evidence supported the contribution of irisin to vascular endothelial cell (ECs) proliferation and apoptosis, further research of irisin involvement in the angiogenesis of ECs was not conclusive. In the current study, it was found that irisin promoted Human Umbilical Vein Endothelial Cell (HUVEC) angiogenesis via increasing migration and tube formation, and attenuated chemically-induced intersegmental vessel (ISV) angiogenic impairment in transgenic TG (fli1: GFP) zebrafish. It was further demonstrated that expression of matrix metalloproteinase (MMP) 2 and 9 were also up-regulated in endothelial cells. We also found that irisin activated extracellular signal–related kinase (ERK) signaling pathways. Inhibition of ERK signaling by using U0126 decreased the pro-migration and pro-angiogenic effect of irisin on HUVEC. Also, U0126 inhibited the elevated expression of MMP-2 and MMP-9 when they were treated with irisin. In summary, these findings provided direct evidence that irisin may play a pivotal role in maintaining endothelium homeostasis by promoting endothelial cell angiogenesis via the ERK signaling pathway.

Protective Effect of Irisin on Atherosclerosis via Suppressing Oxidized Low Density Lipoprotein Induced Vascular Inflammation and Endothelial Dysfunction.

Irisin, a newly discovered myokine, is considered as a promising candidate for the treatment of metabolic disturbances and cardiovascular diseases. In the present study, we used two animal models, apolipoprotein E-deficient mice fed on a high-cholesterol diet and a mouse carotid partial ligation model to test the anti-atherosclerotic effect of irisin. Irisin treatment (0.5 μg/g body weight/day) significantly reduced the severity of aortic atherosclerosis in apolipoprotein E-deficient mice fed on a high-cholesterol diet and suppressed carotid neointima formation in a carotid partial ligation model. It was associated with decreased inflammation and cell apoptosis in aortic tissues. In addition, in a cell culture model, irisin restored ox-LDL-induced human umbilical vein endothelial cell dysfunction by reducing the levels of inflammatory genes via inhibiting the reactive oxygen species (ROS)/ p38 MAPK/ NF-κB signaling pathway activation and inhibiting cell apoptosis via up-regulating Bcl-2 and down-regulating Bax and caspase-3 expression. Our study demonstrated that irisin significantly reduced atherosclerosis in apolipoprotein E-deficient mice via suppressing ox-LDL-induced cell inflammation and apoptosis, which might have a direct therapeutic effect on atherosclerotic diseases.

Targeting Nrf2 by dihydro‐CDDO‐trifluoroethyl amide enhances autophagic clearance and viability of β‐cells in a setting of oxidative stress

Nrf2 appears to be a critical regulator of diabetes in rodents. However, the underlying mechanisms as well as the clinical relevance of the Nrf2 signaling in human diabetes remain to be fully understood. Herein, we report that islet expression of Nrf2 is upregulated at an earlier stage of diabetes in both human and mice. Activation of Nrf2 suppresses oxidative stress and oxidative stress‐induced β‐cell apoptosis while enhancing autophagic clearance in isolated rat islets. Additionally, oxidative stress per se activated autophagy in β‐cells. Thus, these results reveal that Nrf2 drives a novel antioxidant independent autophagic clearance for β‐cell protection in the setting of diabetes.

Deubiquitinating enzyme CYLD mediates pressure overload-induced cardiac maladaptive remodeling and dysfunction via downregulating Nrf2

Ubiquitin proteasome system (UPS) consists of ubiquitin, ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), ubiquitin ligases (E3s), proteasomes, and deubiquitinating enzymes (DUBs). Ubiquitin, E1s, several E2s, E3s, and proteasomes play an important role in the regulation of cardiac homeostasis and dysfunction; however, less is known about the role of DUBs in the heart. Here, we uncovered a crucial role of cyclindromatosis (CYLD), a DUB, in mediating cardiac maladaptive remodeling and dysfunction. CYLD expression was dramatically upregulated in the cardiomyocytes of hypertrophic and failing human and murine hearts. Knockout of CYLD improved survival rate and alleviated cardiac hypertrophy, fibrosis, apoptosis, oxidative stress, and dysfunction in mice that were subjected to sustained pressure overload induced by transverse aortic constriction. Deep sequencing and gene array analyses revealed that the most dramatically changed genes are those involving in the free radical scavenging pathway and cardiovascular disease, including fos, jun, myc, and nuclear factor erythroid-2 related factor 2 (Nrf2) in the heart. Moreover, knockdown of CYLD enhanced mitogen-activated protein kinase (MAPK) ERK- and p38-mediated expression of c-jun, c-fos, and c-myc, which govern Nrf2 expression in cardiomyocytes. The CYLD deficiency-induced suppression of reactive oxygen species (ROS) formation, death and hypertrophy in cardiomyocytes was blocked by additional knockdown of Nrf2. Taken together, our findings demonstrate for the first time that CYLD mediates cardiac maladaptive remodeling and dysfunction, most likely via enhancing myocardial oxidative stress in response to pressure overload. At the molecular level, CYLD interrupts the ERK- and p38-/AP-1 and c-Myc pathways to suppress Nrf2-operated antioxidative capacity, thereby enhancing oxidative stress in the heart.

Irisin Inhibits Atherosclerosis by Promoting Endothelial Proliferation Through microRNA126‐5p

Background Irisin is a newly discovered myokine that has been considered a promising candidate for the treatment of cardiovascular disease through improving endothelial function. However, little is known about the role of irisin in the progression of atherosclerosis. Methods and Results We used a carotid partial ligation model of apolipoprotein E–deficient mice fed on a high‐cholesterol diet to test the anti‐atherosclerosis effect of irisin. Irisin treatment significantly suppressed carotid neointima formation. It was associated with increased endothelial cell proliferation. In addition, irisin promoted human umbilical vein endothelial cell survival via upregulating microRNA126‐5p expression through the ERK signaling pathway. Inhibition of microRNA126‐5p using the microRNA126‐5p inhibitor abolished the prosurvival effect. The same results were demonstrated in vivo as the expression of microRNA126‐5p noticeably increased in ligated carotid artery after irisin treatment. Furthermore, in vivo blockade of microRNA126‐5p expression using the antagomir abolished the inhibitory effects of irisin on neointima formation, lesional lipid deposition, macrophage area, and the pro‐proliferation effects on endothelial cells. Conclusions Taken together, our study demonstrates that irisin significantly reduces atherosclerosis in apolipoprotein E–deficient mice via promoting endothelial cell proliferation through microRNA126‐5p, which may have a direct therapeutic effect on atherosclerotic diseases.

Irisin suppresses the migration, proliferation, and invasion of lung cancer cells via inhibition of epithelial-to-mesenchymal transition

Irisin is involved in promoting metabolism, immune regulation, and affects chronic inflammation in many systemic diseases, including gastric cancer. However, the role of irisin in lung cancer is not well characterized. To determine whether irisin has a protective effect against lung cancer, we cultured A549 and NCI-H446 lung cancer cells and treated them with irisin. We detected the proliferation by MTT assay, and assessed the migration and invasion of the cells by scratch wound healing assay and Tran-swell assay. The expression levels of epithelial-to-mesenchymal transition (EMT) markers and the related signaling pathways were detected by western blot analysis. Meanwhile, an inhibitor of PI3K was used to investigate the effect of irsin. Finally, the expression of Snail was detected. We demonstrated that irisin inhibits the proliferation, migration, and invasion of lung cancer cells, and has a novel role in mediating the PI3K/AKT pathway in the cells. Irisin can reverse the activity of EMT and inhibit the expression of Snail via mediating the PI3K/AKT pathway, which is a key regulator of Snail. These results revealed that irisin inhibited EMT and reduced the invasion of lung cancer cells via the PI3K/AKT/Snail pathway.

Preventive Effect of Dihydromyricetin against Cisplatin-Induced Nephrotoxicity In Vitro and In Vivo

Nephrotoxicity is a frequent severe side effect of cisplatin chemotherapy, limiting its clinical use despite being one of the most potent chemotherapy drugs. Dihydromyricetin is a highly abundant compound purified from the leaves of Ampelopsis grossedentata. Previous studies have demonstrated the anti-inflammatory and antioxidative effects of Dihydromyricetin both in vitro and in vivo, but little is known about the effects of Dihydromyricetin on cisplatin-induced nephrotoxicity and its underlying mechanisms. In the present study, we investigated its potential renoprotective effect and found that Dihydromyricetin ameliorated the renal functional impairment and structural damage caused by cisplatin. Moreover, Dihydromyricetin markedly attenuated cisplatin-induced oxidative stress, as well as protecting against cisplatin-induced inflammation and apoptotic cell death in mouse kidney tissues. These results collectively highlight the potential of DMY as a rational renoprotective agent against cisplatin.

Irisin reverses platelet derived growth factor-BB-induced vascular smooth muscle cells phenotype modulation through STAT3 signaling pathway

Vascular smooth muscle cells (VSMCs) phenotype modulation toward a synthetic phenotype is the main cause of cardiovascular disease. As a newly discovered myokine, Irisin is thought to be a promising candidate for the treatment of metabolic disturbances, as well as cardiovascular disease. However, no evidence has been shown for the direct effect of Irisin on VSMCs phenotype modulation and its underling mechanisms. The aim of this study was to explore the effect of Irisin on VSMCs phenotype modulation and the mechanisms involved. In the present study, it was found that Irisin restored the PDGF-BB-induced VSMCs phenotype modulation which exhibited down-regulation of smooth muscle cells (SMC) expression and up-regulation of matrix synthesis related marker expression, as well as proliferative phenotype. Moreover, our research demonstrated that Irisin further activated STAT3 signaling pathways. Finally, by applying an STAT3 inhibitor, WP1066, we revealed the roles of STAT3 in the PDGF-BB-induced VSMCs phenotype modulation when they were treated with Irisin. Taken together, these results demonstrated that Irisin may play a crucial role in regulating VSMCs phenotype modulation via the STAT3 signaling pathway.

Proteomic analysis revealed the altered kidney protein profile of a cyld knockout mouse model

The aim of this study was to compare the proteomics pattern of the kidneys from Cyld knockout mice with that from normal mouse kidneys and establish a preliminary understanding of the role of Cyld in the kidney. Proteins from the kidneys of knockout Cyld mice and wild-type mice were extracted, isobaric tags for relative and absolute quantitation (iTRAQ) was performed, and the proteomics patterns of the two groups were compared. The genotypes of the mice were verified by polymerase chain reaction. A total of 1748 proteins with a local false discovery rate of ≤5% were identified, among which 1437 proteins were reliably recognized and quantified. The expression of two dysregulated proteins was confirmed by Western blotting. Gene ontology and pathway analyses indicated that the proteins identified were involved in biological processes, cell components, and molecular functions, and participated in different pathways. Some of the proteins identified were relevant to renal function or kidney diseases. The difference between the proteomics profiles of kidneys from Cyld knockout mice and wild-type mice was prominent, which correlates to kidney dysfunction and the development of renal diseases.