Project description:Arterial occlusive diseases are major causes of morbidity and mortality. Blood flow to the affected tissue must be restored quickly if viability and function are to be preserved. Collaterals are artery-to-artery or arteriole-to-arteriole interconnections that can bypass an occlusion by providing an alternative route for blood flow to the affected tissue. The increased flow and sheer stress initiate processes that result in the remodeling (arteriogenesis) of these vessels into efficient conductance arteries. Here we report that the mixed-lineage kinase (MLK) pathway activates cJun NH2-terminal kinase (JNK) in endothelial cells. Disruption of Mlk2/3 or Jnk1/2 genes caused severe blockade of blood flow and failure to recover in the femoral artery ligation model of hindlimb ischemia because of abnormal collateral arteries. We show that the MLK-JNK pathway is essential for patterning and maturation of collateral arteries during development, but this pathway is not required for angiogenesis or arteriogenesis in adults. JNK in endothelial cells promotes Delta-like 4-induced Notch signaling and suppresses excessive sprouting angiogenesis during development. This function of the MLK-JNK pathway contributes to normal formation of native collateral arteries. The MLK-JNK pathway is therefore a key regulatory mechanism for vascular development. These data highlight the crucial importance of the collateral circulation in the response to arterial occlusive diseases. RNA-seq analysis of mouse lung endothelial cells (MLEC) of the following genotypes Cdh5-Cre+ Jnk1+/+ Jnk2+/+ Jnk3-/-(ECtrl), Cdh5-Cre- Jnk1LoxP/LoxP Jnk2LoxP/LoxP Jnk3-/- (EfCtrl), and Cdh5-Cre+ Jnk1LoxP/LoxP Jnk2LoxP/LoxP Jnk3-/- (E3KO). Three separate samples from mouse lung endothelial cells of each genotype were analyzed.
Project description:Arterial occlusive diseases are major causes of morbidity and mortality. Blood flow to the affected tissue must be restored quickly if viability and function are to be preserved. Collaterals are artery-to-artery or arteriole-to-arteriole interconnections that can bypass an occlusion by providing an alternative route for blood flow to the affected tissue. The increased flow and sheer stress initiate processes that result in the remodeling (arteriogenesis) of these vessels into efficient conductance arteries. Here we report that the mixed-lineage kinase (MLK) pathway activates cJun NH2-terminal kinase (JNK) in endothelial cells. Disruption of Mlk2/3 or Jnk1/2 genes caused severe blockade of blood flow and failure to recover in the femoral artery ligation model of hindlimb ischemia because of abnormal collateral arteries. We show that the MLK-JNK pathway is essential for patterning and maturation of collateral arteries during development, but this pathway is not required for angiogenesis or arteriogenesis in adults. JNK in endothelial cells promotes Delta-like 4-induced Notch signaling and suppresses excessive sprouting angiogenesis during development. This function of the MLK-JNK pathway contributes to normal formation of native collateral arteries. The MLK-JNK pathway is therefore a key regulatory mechanism for vascular development. These data highlight the crucial importance of the collateral circulation in the response to arterial occlusive diseases.
Project description:Injury of the arterial endothelial lamina, also called intimal injury, usually occurs after carotid endarterectomy, peripheral artery brachytherapy, stent placement for arterial occlusive disease and balloon dilatation surgeries. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process.
Project description:Occlusive artery disease (CAD) is the leading cause of death worldwide. Bypass graft surgery remains the prevalently performed treatments for occlusive arterial disease, and veins are the most frequently used conduits for surgical revascularization. However, clinical efficacy is highly affected by the long-term potency rates of vein grafts, and no optimal treatments are available for prevention of vein graft restenosis (VGR) until today. Therefore, it is urgent to improve the understanding of molecular mechanisms involved in mediating VGR, and thereby provide potential potent therapeutic targets for prevention of vein graft failure. In this study, we aim to explore potential crucial genes and pathways associated with VGR and provide valid biological information for further investigation of VGR.
Project description:Arteriogenesis is defined as the development of a collateral circulation, bypassing an arterial occlusion. We have previously demonstrated that chronically elevated fluid shear stress completely normalized blood flow in femoral artery ligated rabbits. This was realized by a surgical intervention: the creation of an arterio- venous anastomosis (shunt) between the femoral artery and the accompanying vein. The aim of this study was a gene profiling approach in order to identify differentially expressed genes during collateral growth in the shunt model when compared to pre-existent collaterals (sham).
Project description:This study aims at a comprehensive understanding of the genomic program activated during early-phase of collateral vessel growth in a rat model for cerebral adaptive arteriogenesis (3-VO). While arteriogenesis constitutes a promising therapeutic concept for cerebrovascular ischemia, genomic profiles essential for therapeutic target identification were analysed solely for collateral arteries of the heart and periphery. Despite challenging anatomical conditions of the brain the 3-VO model allows identification of differentially expressed genes during adaptive cerebral arteriogenesis by selective removal of the posterior cerebral artery (PCA). Keywords: early response time course, selective collateral growth, brain
Project description:This study characterizes the response of primary human endothelial cells (human umbilical vein endothelial cells, HUVECs) to the relative shear stress changes that occur during the initiation of arteriogenesis at the entrance regions to a collateral artery network. HUVECs were preconditioned to a baseline level of unidirectional shear of 15 dynes/cm2 for 24 hours. After 24 hours preconditioning, HUVECs were subjected to an arteriogenic stimulus that mimics the shear stress changes observed in the opposing entrance regions into a collateral artery network. The arteriogenic stimulus consisted of a 100% step wise increase in shear stress magnitude to a unidirectional 30 dynes/cm2 in either the same or opposite direction of the preconditioned shear stress. This simulates either the feeding entrance to the collateral artery circuit or the region that drains into the vasculature downstream of an obstruction in a major artery, respectively. In vivo analysis of collateral growth in the mouse hindlimb showed enhanced outward remodeling in the re-entrant (direction reversing) region that reconnects to the downstream arterial tree, suggesting reversal of shear stress direction as a key enhancer of arteriogenesis. Transcriptional profiling using microarray techniques identified that the reversal of shear stress direction, but not an increase in shear stress alone, yielded a broad-based enhancement of the mechanotransduction pathways necessary for the induction of arteriogenesis. Human umbilical vein endothelial cells (HUVECs) were preconditioned to a unidirectional clockwise shear stress of 15 dynes/cm2 for 24 hours. An acute increase in shear stress magnitude to 30 dynes/cm2 in either a clockwise (non-reversed) or counter-clockwise (reversed) direction was applied for 6 hours. An additional preconditioned control culture was maintained under a unidirectional clockwise shear stress of 15 dynes/cm2 and harvested at the same time point, 6 hours post-conditioning. Each condition of reversed, non-reversed, and control was performed in tandem from the same starting cell culture as one replicate. The total experiment consisted of four replicates. Gene transcription was then assessed using microarray expression analysis.
Project description:This study characterizes the response of primary human endothelial cells (human umbilical vein endothelial cells, HUVECs) to the relative shear stress changes that occur during the initiation of arteriogenesis at the entrance regions to a collateral artery network. HUVECs were preconditioned to a baseline level of unidirectional shear of 15 dynes/cm2 for 24 hours. After 24 hours preconditioning, HUVECs were subjected to an arteriogenic stimulus that mimics the shear stress changes observed in the opposing entrance regions into a collateral artery network. The arteriogenic stimulus consisted of a 100% step wise increase in shear stress magnitude to a unidirectional 30 dynes/cm2 in either the same or opposite direction of the preconditioned shear stress. This simulates either the feeding entrance to the collateral artery circuit or the region that drains into the vasculature downstream of an obstruction in a major artery, respectively. In vivo analysis of collateral growth in the mouse hindlimb showed enhanced outward remodeling in the re-entrant (direction reversing) region that reconnects to the downstream arterial tree, suggesting reversal of shear stress direction as a key enhancer of arteriogenesis. Transcriptional profiling using microarray techniques identified that the reversal of shear stress direction, but not an increase in shear stress alone, yielded a broad-based enhancement of the mechanotransduction pathways necessary for the induction of arteriogenesis.
Project description:We established a rat model of myocardial Infarction by performing a surgical operation of left anterior descending coronary artery occlusion under sterie conditions. Wistar rats were previously randomly divided into 4 groups: control, ischemia, ischemia-propranolol, and non-ischemia-propranolol. Our data suggested that propranolol could reverse many microRNAs with too high or too low expression in the ischemia group versus control group. Wistar rats were initially anesthetized with pentobarbital (40 mg/kg, i.v.), which were previously randomly divided into 4 groups: control, ischemia (MI), ischemia-propranolol (MI-PRO), and non-ischemia-propranolol (NMI-PRO). The rat model of MI was established by performing a surgical operation of left anterior descending coronary artery occlusion under sterie conditions. Successful occlusion was confirmed by an increase in the amplitude of R wave of lead I during the first few seconds of each occlusion and elevation of S-T segment of lead II, and a 20-30% decline in the arterial blood pressure compared to the pre-ischemic values mesured by a previously installed ECG recorder (BL 420, ChengDu TME Technology Co, Ltd, ChengDu, China). Propranolol was administrated 2 months before the experiment with daily oral doses of 50 mg/kg. Hearts were quickly isolated after the rats were sacrificed and the ischemic zone of the left ventricle was prepared for the miRNA microarray experiment. Control and NMI-PRO animals underwent open chest procedures without coronary artery occlusion.