Project description:Hypertension is a dominating risk factor for cardiovascular disease. To characterize the genomic response to hypertension, we administered vehicle or angiotensin II to mice and performed gene expression analyses. AngII treatment resulted in a robust increase in blood pressure and altered expression of 235 genes in the aorta, including Gucy1a3 and Gucy1b3 which encode subunits of soluble guanylyl cyclase (sGC). Western blotting and immunohistochemistry confirmed repression of sGC associated with curtailed relaxation via sGC activation. Analysis of transcription factor binding motifs in promoters of differentially expressed genes identified enrichment of motifs for RBPJ, a component of the Notch signaling pathway, and the Notch coactivators FRYL and MAML2 were reduced. Gain and loss of function experiments demonstrated that JAG/NOTCH signaling controls sGC expression together with MAML2 and FRYL. Reduced expression of sGC, correlating with differential expression of MAML2 in stroke prone and spontaneously hypertensive rats was also seen and RNA-Seq data demonstrated correlations between JAG1, NOTCH3, MAML2 and FRYL and the sGC subunits GUCY1A3 and GUCY1B3 in human coronary artery. Notch signaling thus provides a constitutive drive on expression of the major nitric oxide receptor (GUCY1A3/GUCY1B3) in arteries from mice, rats, and humans, and this control mechanism is disturbed in hypertension.
Project description:The aberrant activation of the ERG oncogenic pathway due to TMPRSS2-ERG gene fusions is the major driver of prostate cancer initiation and progression. We identified the alpha1 and beta1 subunits of soluble guanylyl cyclase (GUCY1A1, GUCY1B1) as major ERG-regulated genes in prostate cancer cells. Soluble guanylyl cyclase (sGC) is the major mediator of nitric oxide signaling in cells that, upon nitric oxide binding, catalyzes the synthesis of cGMP and subsequently activates PKG. We showed in ERG-positive PCa cells (VCaP) that cGMP synthesis was significantly elevated by ERG, leading to increased PKG activity and cell proliferation. To further understand the functions of sGC-cGMP pathway in prostate cancer cells, we performed RNA-seq analyses in VCaP cells to identify genes that are regulated by sGC.
Project description:Genomic and behavioral investigations were performed to determine the effects of a mutation in a Drosophila soluble guanylyl cyclase gene. A mutant DGCalpha1[3] third chromosome was crossed into a natural rover (for[R]) or natural sitter (for[s]) genetic background. (See Osborne et al. 1997; PMID: 9242616.) First instar larvae were collected and grown on 60mm Petri plates containing 10 mL of food until mid-third instar. (Approximate density was 3 animals per mL food). Larvae were collected and washed quickly with distilled water and were flash frozen in liquid nitrogen. Co-reared larvae were tested for behavioural effects. Four independent collections were made for each of the two conditions (Rover_DGCalpha1[3] or sitter_DGCalpha1[3]). Keywords = Drosophila Keywords = foraging Keywords = behavior Keywords = cGMP Keywords = guanylyl cyclase Keywords = genetic background
Project description:Genomic and behavioral investigations were performed to determine the effects of a mutation in a Drosophila soluble guanylyl cyclase gene. A mutant DGCalpha1[3] third chromosome was crossed into a natural rover (for[R]) or natural sitter (for[s]) genetic background. (See Osborne et al. 1997; PMID: 9242616.) First instar larvae were collected and grown on 60mm Petri plates containing 10 mL of food until mid-third instar. (Approximate density was 3 animals per mL food). Larvae were collected and washed quickly with distilled water and were flash frozen in liquid nitrogen. Co-reared larvae were tested for behavioural effects. Four independent collections were made for each of the two conditions (Rover_DGCalpha1[3] or sitter_DGCalpha1[3]). Keywords = Drosophila Keywords = foraging Keywords = behavior Keywords = cGMP Keywords = guanylyl cyclase Keywords = genetic background Keywords: other
Project description:Pulmonary arterial hypertension (PAH) is characterized by stenosis and occlusions of small pulmonary arteries, leading to elevated pulmonary arterial pressure and right heart failure. Although accumulating evidence shows the importance of interleukin (IL)-6 in the pathogenesis of PAH, the target cells of IL-6 are poorly understood. Using mice harboring the floxed allele of gp130, a subunit of IL-6 receptor, we found substantial Cre recombination in all hematopoietic cell lineages from the primitive hematopoietic stem cell level in SM22α-Cre mice. We also revealed that a CD4+ cell-specific gp130 deletion ameliorated the phenotype of hypoxia-induced pulmonary hypertension in mice. Disruption of IL-6 signaling via deletion of gp130 in CD4+ T cells inhibited phosphorylation of signal transducer and activator of transcription 3 (STAT3) and suppressed the hypoxia-induced increase in T helper 17 cells. To further examine the role of IL-6/gp130 signaling in more severe PH models, we developed Il6 knockout (KO) rats using the CRISPR/Cas9 system and showed that IL-6 deficiency could improve the pathophysiology in hypoxia-, monocrotaline-, and Sugen5416/hypoxia (SuHx)-induced rat PH models. Phosphorylation of STAT3 in CD4+ cells was also observed around the vascular lesions in the lungs of SuHx rat model, but not in Il6 KO rats. Blockade of IL-6 signaling had an additive effect on conventional PAH therapeutics, such as endothelin receptor antagonist (macitentan) and soluble guanylyl cyclase stimulator (BAY41-2272). These findings suggest that IL-6/gp130 signaling in CD4+ cells plays a critical role in the pathogenesis of PAH.
Project description:Soluble guanylyl cyclase (GC1) is an α/β heterodimer producing cGMP when stimulated by nitric oxide (NO). The NO-GC1-cGMP pathway is essential to cardiovascular homeostasis but is disrupted by oxidative stress, which induces GC1 desensitization to NO by S-nitrosation (SNO) of its cysteines (C). We discovered that under these conditions, GC1-α subunit increases cellular S-nitrosation via transfer of its nitrosothiols to other proteins (transnitrosation). One of the SNO-targets was the oxidized form of the oxido-reductase Thioredoxin1 (oTrx1), which is unilaterally transnitrosated by GC1. GC1-αC610 was a major SNO-donor to oTrx1-C73. Because oTrx1 itself drives transnitrosation, we sought and identified several SNO-proteins targeted by both GC1 and oTrx1. Among them, transnitrosation of RhoA by SNO-GC1 requires oTrx1 as a nitrosothiol relay, suggesting a SNO-GC1→oTrx1→RhoA cascade. We showed that RhoA pathway, which is antagonized by the canonical NO-cGMP signaling, was alternatively inhibited by GC1-α-dependent S-nitrosation under oxidative conditions. We propose that some SNO-GC1’ functions are adaptive responses triggered by oxidation of the canonical NO-cGMP pathway
Project description:Pulmonary arterial hypertension (PAH) is a fatal disease characterized by a progressive increase in pulmonary artery pressure caused by pathological pulmonary artery remodeling. Here, we show that endothelial cell (EC) senescence plays a negative role in pulmonary hypertension via juxtacrine interaction with smooth muscle cells (SMCs). By using EC-specific progeroid mice that we recently generated, we discovered that EC progeria deteriorated vascular remodeling in the lungs, and exacerbated pulmonary hypertension in mice exposed to chronic hypoxia. Mechanistically, senescent ECs overexpressed Notch ligands, which resulted in increased Notch signaling and activated proliferation and migration capacities in neighboring SMCs. Pharmacological inhibition of Notch signaling reduced the effects of senescent ECs on SMCs functions in vitro, and improved the worsened pulmonary hypertension in EC-specific progeroid mice in vivo. Our findings show that EC senescence is a critical disease-modifying factor in PAH and that EC-mediated Notch signaling is a pharmacotherapeutic target for the treatment of PAH, particularly in the elderly.
Project description:Stone1996 - activation of soluble guanylate
cyclase by nitric oxide
This features the two step binding of
NO to soluble Guanylyl Cyclase as proposed by
Stone
JR, Marletta MA. Biochemistry (1996) 35(4):1093-9 . There is a
fast step binding scheme and a slow step binding scheme. The
difference lies in the binding of a NO to a non-heme site on sGC,
which may not necessarily be the same site of binding during the
initial binding. The rates have been directly used models.
This model is described in the article:
Spectral and kinetic studies
on the activation of soluble guanylate cyclase by nitric
oxide.
Stone JR, Marletta MA.
Biochemistry 1996 Jan; 35(4):
1093-1099
Abstract:
The soluble form of guanylate cyclase (sGC) is the only
definitive receptor for the signaling agent nitric oxide (.NO).
The enzyme is a heterodimer of homologous subunits in which
each subunit binds 1 equiv of 5-coordinate high-spin heme. .NO
increases the Vmax of sGC up to 400-fold and has previously
been shown to bind to the heme to form a 5-coordinate complex.
Using stopped-flow spectrophotometry, it is demonstrated that
the binding of .NO to the heme of sGC is a complex process. .NO
first binds to the heme to form a 6-coordinate nitrosyl
complex, which then converts to a 5-coordinate nitrosyl complex
through one of two ways. For 28 +/- 4% of the heme, the
6-coordinate nitrosyl complex rapidly (approximately 20 s-1)
converts to the 5-coordinate complex. For the remaining 72 +/-
4% of the heme, the conversion of the 6-coordinate nitrosyl
complex to a 5-coordinate nitrosyl complex is slow (0.1-1.0
s-1) and is dependent upon the interaction of .NO with an
unidentified non-heme site on the protein. The heme (200 nM)
was completely converted to the 5-coordinate state with as
little as 500 nM .NO, and the equilibrium dissociation constant
of .NO for activating the enzyme was determined to be < or =
250 nM. Gel-filtration analysis indicates that the binding of
.NO to the heme has no effect on the native molecular mass of
the protein. Correlation of electronic absorption spectra with
activity measurements indicates that the 5-coordinate nitrosyl
form of the enzyme is activated relative to the resting
5-coordinate ferrous form of the enzyme.
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