Project description:Purpose: To investigate biomechanical cues influencing heart morphogenesis. Methods: Approximate 1000 hearts dissected from 96 hpf Tg(myl7:mCherry) and tricaine-treated Tg(myl7:mCherry) embryos were collected for RNA sequencing. Results: 2,013 up-regulated and 2,517 down-regulated genes were identified. Enrichment analysis of DEGs encoding TFs affected by perturbing biomechanical forces identified several pathways known to be involved in heart development, including the transforming growth factor beta (TGFβ) signaling and Notch signaling pathways. Further analysis demonstrated id2b expression in embryonic hearts depends on blood flow. Conclusions: we analyzed embryonic zebrafish hearts without contractility and identified genes that are regulated by biomechanical forces. Specifically, id2b was identified as a blood flow sensitive gene.
Project description:Recently, we showed that disturbed flow caused by a partial ligation ofmouse carotid artery rapidly induces atherosclerosis. Analysis of mechanosenstive microRNA in the mouse carotid endothelium. In this study, we examined the microRNAs that respond differentially to blood flow pattern in the mouse carotid endothelium. We surgically induced disturbed blood flow in the left common carotid cartery (LCA) using partial carotid ligation surgery while the right carotid artery was left undisturbed. The hypothesis tested here is that turbulent or disturbed blood flow across the left carotid artery endothelium will affect endothelial genes and microRNAS. Identifying flow-sensitive microRNAs will provide important information about how endothelium responds to d-flow and regulates endothelial function and progression of atherosclerosis. Deter- mining the functional importance of these novel mechanosensitive microRNAS may provide important insights into understanding vascular biology and atherosclerosis.
Project description:Recently, we showed that disturbed flow caused by a partial ligation ofmouse carotid artery rapidly induces atherosclerosis. Analysis of mechanosenstive microRNA in the mouse carotid endothelium. In this study, we examined the microRNAs that respond differentially to blood flow pattern in the mouse carotid endothelium. We surgically induced disturbed blood flow in the left common carotid cartery (LCA) using partial carotid ligation surgery while the right carotid artery was left undisturbed. The hypothesis tested here is that turbulent or disturbed blood flow across the left carotid artery endothelium will affect endothelial genes and microRNAS. Identifying flow-sensitive microRNAs will provide important information about how endothelium responds to d-flow and regulates endothelial function and progression of atherosclerosis. Deter- mining the functional importance of these novel mechanosensitive microRNAS may provide important insights into understanding vascular biology and atherosclerosis. We used 6- to 8-week-old male C57Bl/6 mice (The Jackson Laboratory) according to the approved Institutional Animal Care and Use Committee protocol by Emory University. Mice were subjected to partial carotid ligation surgery under anesthesia. Briefly, 3 of 4 caudal branches of LCA (left external carotid, internal carotid, and occipital artery) were ligated with 6-0 silk suture, although the superior thyroid artery was left intact. Development of low and oscillatory blood flow in the Left Carotid Artery of each mouse was determined by ultrasound measurements.
Project description:Previous studies have shown that the vascular system regulates brain clearance via arterial blood flow and the lymphatic drainage of CSF. Here, we examined the hypothesis that cerebral venous blood flow may participate in brain clearance as an intermediate compartment between the arterial and lymphatic poles of the vascular system. Transcriptomic analyses provided insights into the molecular mechanisms driving dural lymphatic remodeling within the dura mater.
Project description:Atherosclerosis preferentially occurs in arterial regions of disturbed blood flow (d-flow), which alters gene expression, endothelial function, and atherosclerosis. Here, we show that d-flow regulates genome-wide DNA methylation patterns in a DNA methyltransferase (DNMT)-dependent manner. D-flow induced expression of DNMT1 in mouse arterial endothelium in vivo and in cultured endothelial cells by oscillatory shear (OS) in vitro. The DNMT inhibitor 5-Aza-2’deoxycytidine (5Aza) or DNMT1 siRNA significantly reduced OS-induced endothelial inflammation. Moreover, 5Aza reduced lesion formation in two ApoE-/- mouse atherosclerosis models. To identify the 5Aza mechanisms, we conducted two genome-wide studies: reduced representation bisulfite sequencing (RRBS) and microarray using endothelial-enriched gDNA and RNA, respectively, from the partially-ligated left carotid artery (LCA exposed to d-flow) and the right contralateral control (RCA) of mice treated with 5Aza or vehicle. Systems biological analyses using RRBS and transcriptome data revealed 11 mechanosensitive genes whose promoters were hypermethylated under d-flow conditions, but rescued by 5Aza treatment. Of those, the two transcription factors HoxA5 and Klf3 contain cAMP- response-elements, and their methylation status could serve as a mechanosensitive master switch in gene expression. Our results demonstrate that d-flow controls epigenomic DNA methylation patterns in a DNMT-dependent manner, which in turn alters endothelial gene expression and induces atherosclerosis. We used 6- to 8-week-old male C57Bl/6 mice (The Jackson Laboratory) according to the approved Institutional Animal Care and Use Committee protocol by Emory University. Mice were subjected to partial carotid ligation surgery under anesthesia. Briefly, 3 of 4 caudal branches of LCA (left external carotid, internal carotid, and occipital artery) were ligated with 6-0 silk suture, although the superior thyroid artery was left intact. Development of low and oscillatory blood flow in the Left Carotid Artery of each mouse was determined by ultrasound measurements. Each sample contained total RNA from 3 pooled RCAs or LCAs. We ran 3 samples of LCA, RCA, AzaLCA, and AzaRCA on 2 microarrays.
Project description:Bone adaptation to mechanical loading is regulated via signal transduction by mechano-sensing osteocytes. Mineral-embedded osteocytes experience strain-induced interstitial fluid flow and fluid shear stress, and broad shifts in gene expression are key components in the signaling pathways that regulate bone turnover. RNA sequencing analysis, or RNA-Seq, enables more complete characterization of mechano-sensitive transcriptome regulation than previously possible. We hypothesized that RNA-Seq of osteocytic MLO-Y4 cells reveals both expected and novel gene transcript regulation in cells previously fluid flowed and analyzed using gene microarrays (Govey et al., J Biomech, 2014). MLO-Y4 cells were flowed for 2 h with 1 Pa oscillating fluid shear stress and post-incubated 2 h. RNA-Seq of original samples detected 58 fluid flow-regulated gene transcripts (p-corrected<0.05) versus 65 transcripts detected by microarray. However, RNA-Seq demonstrated greater dynamic range, with all 58 transcripts >1.5 fold-change whereas 10 of 65 met this cut-off by microarray. Analyses were complimentary in patterns of regulation, though only 6 transcripts were significant in both analyses: Cxcl5, Cxcl1, Zc3h12a, Ereg, Slc2a1, and Egln1. As part of a broad inflammatory response inferred by gene ontology analyses, we again observed greatest up-regulation of inflammatory C-X-C motif chemokines, and newly implicated HIF-1? and AMPK signaling pathways. Importantly, we detected both expected mechano-sensitive transcripts (e.g. Nos2, Ptgs2, Ccl7) and transcripts not previously identified as mechano-sensitive, e.g. Ccl2. We found RNA-Seq advantageous over microarrays because of its ability to analyze unbiased estimation of gene expression, informing our understanding of osteocyte signaling.
Project description:Atherosclerosis preferentially occurs in arterial regions of disturbed blood flow (d-flow), which alters gene expression, endothelial function, and atherosclerosis. Here, we show that d-flow regulates genome-wide DNA methylation patterns in a DNA methyltransferase (DNMT)-dependent manner. D-flow induced expression of DNMT1 in mouse arterial endothelium in vivo and in cultured endothelial cells by oscillatory shear (OS) in vitro. The DNMT inhibitor 5-Aza-2’deoxycytidine (5Aza) or DNMT1 siRNA significantly reduced OS-induced endothelial inflammation. Moreover, 5Aza reduced lesion formation in two ApoE-/- mouse atherosclerosis models. To identify the 5Aza mechanisms, we conducted two genome-wide studies: reduced representation bisulfite sequencing (RRBS) and microarray using endothelial-enriched gDNA and RNA, respectively, from the partially-ligated left carotid artery (LCA exposed to d-flow) and the right contralateral control (RCA) of mice treated with 5Aza or vehicle. Systems biological analyses using RRBS and transcriptome data revealed 11 mechanosensitive genes whose promoters were hypermethylated under d-flow conditions, but rescued by 5Aza treatment. Of those, the two transcription factors HoxA5 and Klf3 contain cAMP- response-elements, and their methylation status could serve as a mechanosensitive master switch in gene expression. Our results demonstrate that d-flow controls epigenomic DNA methylation patterns in a DNMT-dependent manner, which in turn alters endothelial gene expression and induces atherosclerosis.
Project description:To investigate a non-invasive strategy for immune monitoring the peripheral blood by flow cytometry, to address the critical need to itdentify predictive immunological biomarkers that correlate with treatment response Peripheral blood mononuclear cells (PBMCs) from 19 non–small-cell lung cancer (NSCLC) patients before and after ICI treatment and four healthy human donors were evaluated, utilizing spectral flow to monitor 24 immune cell markers simultaneously over the course of treatment. We performed immune cell profiling analysis using data obtained from RNA-seq of 19 different patients before and after immunotherapy, to validate the multi-color flow based immune profiling
Project description:SOX13 was identified as a novel flow-sensitive transceiption factor. We found that siRNA-mediated knockdown of SOX13 increased endothelial inflammatory responses even under the unidirectional laminar shear stress (ULS, mimicking s-flow) condition. To understand the underlying mechanisms, we conducted an RNAseq study in HAECs treated with SOX13 siRNA under shear conditions (ULS vs. oscillatory shear mimicking d-flow). We found 94 downregulated and 40 upregulated genes that changed in a shear- and SOX13-dependent manner. Several cytokines, including CXCL10 and CCL5, were the most strongly upregulated genes in HAECs treated with SOX13 siRNA.