scholarly journals Role of Fructokinases in the Development and Function of the Vascular System

2011 ◽  
Author(s):  
David Granot ◽  
Noel Michelle Holbrook
Keyword(s):  
Hydraulic Conductivity ◽  
Hormonal Regulation ◽  
Vascular System ◽  
Vascular Development ◽  
Vascular Anatomy ◽  
Sugar Metabolism ◽  
Phloem Transport ◽  
Vascular Tissues ◽  
And Function

Plant vascular tissues are superhighways whose development and function have profound implications for productivity, yield and stress response. Preliminary studies by the PI indicated that sugar metabolism mediated by fructokinases (FRKs) has a pronounced effect on the transport properties of the xylem. The goal of this research was to determine how the main fructokinase gene, FRK2, and the only plastidic fructokinase, FRK3, influence vascular development and physiology, emphasizing processes that occur at both the cellular and organismic level. We found that both genes are expressed in vascular tissues, but FRK3 is expressed primarily in vascular tissues of mature petioles. Vascular anatomy of plants with antisense suppression of FRK2 uncovered that FRK2 is necessary for xylem and phloem development, most likely due to its role in vascular cell-wall synthesis, and affects vascular development all over the plant. As a result, suppression of FRK2 reduced hydraulic conductivity of roots, stem and leaves and restricted sugar phloem transport. Vascular anatomy of plants with RNAi suppression of FRK3 uncovered that FRK3 is required for vascular development in mature petiole but its role is partially complemented by FRK2. Suppression of FRK3 combined with partial suppression of FRK2 had effects completely different from that of FRK2 suppression, resulting in wilting of mature leaves rather than young leaves of FRK2 suppressed plants, and decreased export of photoassimilates. This primary effect of FRK2 suppression on mature petioles had a secondary effect, reducing the hydraulic conductivity in roots and stem. The very fact that a plastidic fructokinase plays a role in vascular development is quite surprising and we are still seeking to uncover its metabolic mode-of-action. Yet, it is clear that these two fructokinases have different roles in the coordination between photosynthetic capacity and vascular development. We have started analyzing the role of the last third FRK, FRK1, and discovered that it is also expressed exclusively in vascular tissues. It appears therefore, that all FRKs studied here are involved in vascular development.   An interesting unexpected outcome of this study was the connection of FRK2 with hormonal regulation of vascular development, most likely auxin. This observation together with the yet to be solved questions on the exact roles of FRK3 are the subjects of our current efforts. 

scholarly journals Chicken Is a Useful Model to Investigate the Role of Adipokines in Metabolic and Reproductive Diseases

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Namya Mellouk ◽  
Christelle Ramé ◽  
Alix Barbe ◽  
Jérémy Grandhaye ◽  
Pascal Froment ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Structure And Function ◽  
Avian Species ◽  
Endocrine Organ ◽  
Metabolic Systems ◽  
Long Time ◽  
And Function ◽  
New Generation ◽  
Reproductive Processes

Reproduction is a complex and essential physiological process required by all species to produce a new generation. This process involves strict hormonal regulation, depending on a connection between the hypothalamus-pituitary-gonadal axis and peripheral organs. Metabolic homeostasis influences the reproductive functions, and its alteration leads to disturbances in the reproductive functions of humans as well as animals. For a long time, adipose tissue has been recognised as an endocrine organ but its ability to secrete and release hormones called adipokines is now emerging. Adipokines have been found to play a major role in the regulation of metabolic and reproductive processes at both central and peripheral levels. Leptin was initially the first adipokine that has been described to be the most involved in the metabolism/reproduction interrelation in mammals. In avian species, the role of leptin is still under debate. Recently, three novel adipokines have been discovered: adiponectin (ADIPOQ, ACRP30), visfatin (NAMPT, PBEF), and chemerin (RARRES2, TIG2). However, their mode of action between mammalian and nonmammalian species is different due to the different reproductive and metabolic systems. Herein, we will provide an overview of the structure and function related to metabolic and reproductive mechanisms of the latter three adipokines with emphasis on avian species.

scholarly journals Chronic hypertension increases aortic endothelial hydraulic conductivity by upregulating endothelial aquaporin-1 expression

2017 ◽  
Vol 313 (5) ◽  
pp. H1063-H1073 ◽  
Author(s):  
Jimmy Toussaint ◽  
Chirag Bharavi Raval ◽  
Tieuvi Nguyen ◽  
Hadi Fadaifard ◽  
Shripad Joshi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Hydraulic Conductivity ◽  
Water Transport ◽  
Aortic Endothelial Cells ◽  
Rat Models ◽  
Aquaporin 1 ◽  
Hypertensive Rat ◽  
And Function ◽  
Aortic Endothelial

Numerous studies have examined the role of aquaporins in osmotic water transport in various systems, but virtually none have focused on the role of aquaporin in hydrostatically driven water transport involving mammalian cells save for our laboratory’s recent study of aortic endothelial cells. Here, we investigated aquaporin-1 expression and function in the aortic endothelium in two high-renin rat models of hypertension, the spontaneously hypertensive genetically altered Wistar-Kyoto rat variant and Sprague-Dawley rats made hypertensive by two-kidney, one-clip Goldblatt surgery. We measured aquaporin-1 expression in aortic endothelial cells from whole rat aortas by quantitative immunohistochemistry and function by measuring the pressure-driven hydraulic conductivities of excised rat aortas with both intact and denuded endothelia on the same vessel. We used them to calculate the effective intimal hydraulic conductivity, which is a combination of endothelial and subendothelial components. We observed well-correlated enhancements in aquaporin-1 expression and function in both hypertensive rat models as well as in aortas from normotensive rats whose expression was upregulated by 2 h of forskolin treatment. Upregulated aquaporin-1 expression and function may be a response to hypertension that critically determines conduit artery vessel wall viability and long-term susceptibility to atherosclerosis. NEW & NOTEWORTHY The aortic endothelia of two high-renin hypertensive rat models express greater than two times the aquaporin-1 and, at low pressures, have greater than two times the endothelial hydraulic conductivity of normotensive rats. Data are consistent with theory predicting that higher endothelial aquaporin-1 expression raises the critical pressure for subendothelial intima compression and for artery wall hydraulic conductivity to drop.

scholarly journals Role of nitric oxide in placental vascular development and function

Placenta ◽  
2011 ◽  
Vol 32 (11) ◽  
pp. 797-805 ◽  
Author(s):  
B.J. Krause ◽  
M.A. Hanson ◽  
P. Casanello
Keyword(s):  
Nitric Oxide ◽  
Vascular Development ◽  
And Function

scholarly journals The role of microRNAs in the legume–Rhizobium nitrogen-fixing symbiosis

2020 ◽  
Vol 71 (5) ◽  
pp. 1668-1680 ◽  
Author(s):  
Nhung T Hoang ◽  
Katalin Tóth ◽  
Gary Stacey
Keyword(s):  
Vascular System ◽  
Regulation Of Gene Expression ◽  
Lotus Japonicus ◽  
Nodule Formation ◽  
Nitrogen Fixing ◽  
Rna Molecules ◽  
Physiological Processes ◽  
Leaf Tissues ◽  
And Function

Abstract Under nitrogen starvation, most legume plants form a nitrogen-fixing symbiosis with Rhizobium bacteria. The bacteria induce the formation of a novel organ called the nodule in which rhizobia reside as intracellular symbionts and convert atmospheric nitrogen into ammonia. During this symbiosis, miRNAs are essential for coordinating the various plant processes required for nodule formation and function. miRNAs are non-coding, endogenous RNA molecules, typically 20–24 nucleotides long, that negatively regulate the expression of their target mRNAs. Some miRNAs can move systemically within plant tissues through the vascular system, which mediates, for example, communication between the stem/leaf tissues and the roots. In this review, we summarize the growing number of miRNAs that function during legume nodulation focusing on two model legumes, Lotus japonicus and Medicago truncatula, and two important legume crops, soybean (Glycine max) and common bean (Phaseolus vulgaris). This regulation impacts a variety of physiological processes including hormone signaling and spatial regulation of gene expression. The role of mobile miRNAs in regulating legume nodule number is also highlighted.

scholarly journals Pit and tracheid anatomy explain the hydraulic safety- but not the hydraulic efficiency of 28 conifer species

2021 ◽  
Author(s):  
Yanjun Song ◽  
Lourens Poorter ◽  
Angelina Horsting ◽  
Sylvain Delzon ◽  
Frank Sterck
Keyword(s):  
Hydraulic Conductivity ◽  
Vascular System ◽  
Common Garden ◽  
Hydraulic Efficiency ◽  
Conifer Species ◽  
Hydraulic Safety ◽  
Valve Effect ◽  
Embolism Resistance ◽  
Underlying Mechanisms ◽  
And Function

Abstract Conifers face increased drought mortality risks because of drought-induced embolism in their vascular system. Variation in embolism resistance may result from species differences in pit structure and function, as pits control the air seeding between water transporting conduits. This study quantifies variation in embolism resistance and hydraulic conductivity for 28 conifer species grown in a 50-year-old common garden experiment and assesses the underlying mechanisms. Conifer species with a small pit aperture, high pit aperture resistance and large valve effect were more resistant to embolism, as they all may reduce air seeding. Surprisingly, hydraulic conductivity was only negatively correlated with tracheid cell wall thickness. Embolism resistance and its underlying pit traits related to pit size and sealing were stronger phylogenetically controlled than hydraulic conductivity and anatomical tracheid traits. Conifers differed in hydraulic safety and hydraulic efficiency, but there was no trade-off between safety and efficiency because they are driven by different xylem anatomical traits that are under different phylogenetic control.

Role of Androgen Dependent TFPI-Regulating Protein (ADTRP) in Vascular Development and Function

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 556-556 ◽  
Author(s):  
Maulin Mukeshchandra Patel ◽  
Robert Silasi-Mansat ◽  
Ravi Shankar Keshari ◽  
Christopher L. Sansam ◽  
David A. Jones ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Target Genes ◽  
Vascular Development ◽  
The Novel ◽  
Canonical Wnt Signaling ◽  
And Function ◽  
Canonical Wnt

Abstract We used in vitro and in vivo models to characterize the physiological role of the novel protein encoded by C6ORF105. This gene's expression is androgen-responsive, and the encoded protein is predicted to be palmitoylated and membrane multi-spanning. Previously we showed that C6ORF105 expression co-regulates with tissue factor pathway inhibitor (TFPI)in human endothelial cells (EC); hence we named this protein "androgen-dependent TFPI-regulating protein" (ADTRP). Using in vitro cell-based TOP-Flash reporter assay we identified ADTRP as a negative regulator of canonical Wnt signaling in human cells. Overexpressing ADTRP in HEK293T cells inhibited the activity of beta-catenin/TCF-dependent transcriptional reporter, while silencing ADTRP increased the expression of Wnt target genes LEF-1, AXIN-2, IL-8 and DKK-2 in EA.hy926 EC line and HUVEC. Addition of LiCl showed that the effect of ADTRP was upstream of GSK3, therefore we focused the investigations on the Wnt signalosome proteins. ADTRP expression in HEK293T cells led to decreased phosphorylation of Wnt co-receptor LRP6, suggesting that ADTRP can affect this critical membrane-located event of Wnt signaling. Furthermore, ADTRP expression in reporter cells transfected with a constitutively phosphorylated form of LRP6 (LRP6DN mutant) inhibited Wnt3a- induced signaling, which suggests that ADTRP can interfere with events downstream of LRP6 phosphorylation, such as Axin-2 binding. Altogether, these data indicate that the Wnt signaling inhibitory activity of ADTRP takes place at the plasma membrane level. Site directed mutagenesis of the predicted palmitoylation site Cys61 showed that Wnt inhibitory effects of ADTRP require palmitoyl-mediated anchoring, highlighting the importance of proper membrane location of ADTRP for Wnt pathway inhibition. In vivo morpholino-based knockdown of adtrp in zebrafish embryos produced aberrant angiogenesis, defective branching and ruptured vessels, hemorrhage spots, pericardial edema and slow heart-beat, all reminiscent of defects caused by activation of canonical Wnt signaling. Indeed, adtrp knock down increased Wnt mediated lef-1 and pax-2a as well as mmp2 and mmp9 mRNA expression. Co-injection of ADTRP mRNA partially recovered the adtrp morpholino- induced morphologic abnormalities. Also, knock down of adtrp in a Wnt reporter zebrafish showed increased expression of ectopic Wnt signaling. Furthermore, our recently established Adtrp-/- mice also display some typical Wnt-mediated vascular defects, including: (i) abnormal patterning, increased capillary tortuosity, abnormal branching and increased density of the capillary network; (ii) dilated vessels, especially venules and veins; (iii) increased leakeage of permeability tracers (Evans blue and fluorescent dextran) without evident changes in endothelial junctions; (iv) hemorrhage spots in the skin, meningeal layers, heart, bladder and kidneys; (v) intravascular and interstitial fibrin deposition in the lung, liver and kidney. ADTRP deficiency decreased plasma TFPI antigen by ~2-times. Furthermore, TFPI antigen and anticoagulant activity in lung extracts and isolated lung EC were similarly decreased, which confirms our previous in vitro data. We aslo noticed increased tail bleeding time (>500 sec vs. 200 sec in WT littermates) and blood volume loss, which likely was caused by increased dilation of the tail vein. Gene expression analysis of whole organs showed upregulation of Wnt target genes involved in vascular contractility (Nos3), and extracellular matrix remodeling (Mmp2). Similarly, skin fibroblasts and lung EC isolated from Adtrp-/- mice showed increased expression of Wnt target genes (Lef-1, Cyclin D, Dkk2, c-Myc), which indicates constitutive activation of canonical Wnt signaling. In conclusion, we used genetic animal models and cell culture systems to show for the first time that the novel protein ADTRP plays major roles in vascular development and function. Lack of, or low levels of ADTRP associate with activation of coagulation and vascular development defects, which may be due, at least in part, to intrinsic high levels of ectopic canonical Wnt signaling. Disclosures No relevant conflicts of interest to declare.

scholarly journals The Fst/Ldr Family of Type I TA System Toxins: Potential Roles in Stress Response, Metabolism and Pathogenesis

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 474
Author(s):  
Keith Weaver
Keyword(s):  
Sugar Metabolism ◽  
Type I ◽  
Gram Positive ◽  
Gram Negative ◽  
Over Expression ◽  
Gram Positive Bacteria ◽  
The Family ◽  
Peptide Toxins ◽  
And Function

The parpAD1 locus was the first type I toxin–antitoxin (TA) system described in Gram-positive bacteria and was later determined to be the founding member of a widely distributed family of plasmid- and chromosomally encoded TA systems. Indeed, homology searches revealed that the toxin component, FstpAD1, is a member of the Fst/Ldr superfamily of peptide toxins found in both Gram-positive and Gram-negative bacteria. Regulation of the Fst and Ldr toxins is distinct in their respective Gram-positive and Gram-negative hosts, but the effects of ectopic over-expression are similar. While, the plasmid versions of these systems appear to play the canonical role of post-segregational killing stability mechanisms, the function of the chromosomal systems remains largely obscure. At least one member of the family has been suggested to play a role in pathogenesis in Staphylococcus aureus, while the regulation of several others appear to be tightly integrated with genes involved in sugar metabolism. After a brief discussion of the regulation and function of the foundational parpAD1 locus, this review will focus on the current information available on potential roles of the chromosomal homologs.

scholarly journals Salinity Effects on Sugar Homeostasis and Vascular Anatomy in the Stem of the Arabidopsis Thaliana Inflorescence

2019 ◽  
Vol 20 (13) ◽  
pp. 3167 ◽  
Author(s):  
Sahar Sellami ◽  
Rozenn Le Hir ◽  
Michael R. Thorpe ◽  
Françoise Vilaine ◽  
Nelly Wolff ◽  
...  
Keyword(s):  
Sucrose Synthase ◽  
Cell Walls ◽  
Essential Role ◽  
High Salinity ◽  
Vascular Anatomy ◽  
Sugar Metabolism ◽  
Phloem Loading ◽  
Vascular Tissues ◽  
Sugar Transporters ◽  
Genes Encoding

The regulation of sugar metabolism and partitioning plays an essential role for a plant’s acclimation to its environment, with specific responses in autotrophic and heterotrophic organs. In this work, we analyzed the effects of high salinity on sugar partitioning and vascular anatomy within the floral stem. Stem sucrose and fructose content increased, while starch reduced, in contrast to the response observed in rosette leaves of the same plants. In the stem, the effects were associated with changes in the expression of SWEET and TMT2 genes encoding sugar transporters, SUSY1 encoding a sucrose synthase and several FRK encoding fructokinases. By contrast, the expression of SUC2, SWEET11 and SWEET12, encoding sugar transporters for phloem loading, remained unchanged in the stem. Both the anatomy of vascular tissues and the composition of xylem secondary cell walls were altered, suggesting that high salinity triggered major readjustments of sugar partitioning in this heterotrophic organ. There were changes in the composition of xylem cell walls, associated with the collapse and deformation of xylem vessels. The data are discussed regarding sugar partitioning and homeostasis of sugars in the vascular tissues of the stem.

scholarly journals Attenuating Cardiac Pulsations within the Cochlea: Structure and Function of Tortuous Vessels Feeding Stria Vascularis

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mattia Carraro ◽  
Jaina Negandhi ◽  
Jafri Kuthubutheen ◽  
Evan J. Propst ◽  
Lukas Kus ◽  
...  
Keyword(s):  
Hair Cells ◽  
Stria Vascularis ◽  
Vascular Anatomy ◽  
Biological Noise ◽  
Pulsatile Blood Flow ◽  
Cochlear Hair Cells ◽  
Cardiac Pulse ◽  
And Function ◽  
Pressure Changes

The mammalian ear has an extraordinary capacity to detect very low-level acoustic signals from the environment. Sound pressures as low as a few μPa (−10 dB SPL) can activate cochlear hair cells. To achieve this sensitivity, biological noise has to be minimized including that generated by cardiovascular pulsation. Generally, cardiac pressure changes are transmitted to most peripheral capillary beds; however, such signals within the stria vascularis of the cochlea would be highly disruptive. Not least, it would result in a constant auditory sensation of heartbeat. We investigate special adaptations in cochlear vasculature that serve to attenuate cardiac pulse signals. We describe the structure of tortuous arterioles that feed stria vascularis as seen in corrosion casts of the cochlea. We provide a mathematical model to explain the role of this unique vascular anatomy in dampening pulsatile blood flow to the stria vascularis.

Sign in / Sign up

Export Citation Format

Share Document