scholarly journals A Na+/K+ ATPase Pump Regulates Chondrocyte Differentiation and Bone Length Variation in Mice

2021 ◽  
Vol 9 ◽  
Author(s):  
Marta Marchini ◽  
Mitchell R. Ashkin ◽  
Melina Bellini ◽  
Margaret Man-Ger Sun ◽  
Matthew Lloyd Workentine ◽  
...  
Keyword(s):  
Chondrocyte Differentiation ◽  
Length Variation ◽  
Stem Cell Markers ◽  
Altered Expression ◽  
Limb Bone ◽  
Bone Length ◽  
Length Regulation ◽  
Membrane Bound

The genetic and developmental mechanisms involved in limb formation are relatively well documented, but how these mechanisms are modulated by changes in chondrocyte physiology to produce differences in limb bone length remains unclear. Here, we used high throughput RNA sequencing (RNAseq) to probe the developmental genetic basis of variation in limb bone length in Longshanks, a mouse model of experimental evolution. We find that increased tibia length in Longshanks is associated with altered expression of a few key endochondral ossification genes such as Npr3, Dlk1, Sox9, and Sfrp1, as well reduced expression of Fxyd2, a facultative subunit of the cell membrane-bound Na+/K+ ATPase pump (NKA). Next, using murine tibia and cell cultures, we show a dynamic role for NKA in chondrocyte differentiation and in bone length regulation. Specifically, we show that pharmacological inhibition of NKA disrupts chondrocyte differentiation, by upregulating expression of mesenchymal stem cell markers (Prrx1, Serpina3n), downregulation of chondrogenesis marker Sox9, and altered expression of extracellular matrix genes (e.g., collagens) associated with proliferative and hypertrophic chondrocytes. Together, Longshanks and in vitro data suggest a broader developmental and evolutionary role of NKA in regulating limb length diversity.

scholarly journals Identification of a microRNA signature in renal fibrosis: role of miR-21

2011 ◽  
Vol 301 (4) ◽  
pp. F793-F801 ◽  
Author(s):  
Abolfazl Zarjou ◽  
Shanzhong Yang ◽  
Edward Abraham ◽  
Anupam Agarwal ◽  
Gang Liu
Keyword(s):  
Epithelial Cells ◽  
Renal Fibrosis ◽  
Transforming Growth Factor ◽  
Response To Treatment ◽  
Tubular Epithelial Cells ◽  
Altered Expression ◽  
Tnf Α ◽  
Tgf Β1

Renal fibrosis is a final stage of many forms of kidney disease and leads to impairment of kidney function. The molecular pathogenesis of renal fibrosis is currently not well-understood. microRNAs (miRNAs) are important players in initiation and progression of many pathologic processes including diabetes, cancer, and cardiovascular disease. However, the role of miRNAs in kidney injury and repair is not well-characterized. In the present study, we found a unique miRNA signature associated with unilateral ureteral obstruction (UUO)-induced renal fibrosis. We found altered expression in UUO kidneys of miRNAs that have been shown to be responsive to stimulation by transforming growth factor (TGF)-β1 or TNF-α. Among these miRNAs, miR-21 demonstrated the greatest increase in UUO kidneys. The enhanced expression of miR-21 was located mainly in distal tubular epithelial cells. miR-21 expression was upregulated in response to treatment with TGF-β1 or TNF-α in human renal tubular epithelial cells in vitro. Furthermore, we found that blocking miR-21 in vivo attenuated UUO-induced renal fibrosis, presumably through diminishing the expression of profibrotic proteins and reducing infiltration of inflammatory macrophages in UUO kidneys. Our data suggest that targeting specific miRNAs could be a novel therapeutic approach to treat renal fibrosis.

scholarly journals Medawar’s PostEra: Galectins Emerged as Key Players During Fetal-Maternal Glycoimmune Adaptation

2021 ◽  
Vol 12 ◽  
Author(s):  
Ellen Menkhorst ◽  
Nandor Gabor Than ◽  
Udo Jeschke ◽  
Gabriela Barrientos ◽  
Laszlo Szereday ◽  
...  
Keyword(s):  
Immune Cell ◽  
Successful Pregnancy ◽  
Fetal Health ◽  
The Past ◽  
Mammalian Embryogenesis ◽  
Carbohydrate Ligands ◽  
Membrane Bound

Lectin-glycan interactions, in particular those mediated by the galectin family, regulate many processes required for a successful pregnancy. Over the past decades, increasing evidence gathered from in vitro and in vivo experiments indicate that members of the galectin family specifically bind to both intracellular and membrane bound carbohydrate ligands regulating angiogenesis, immune-cell adaptations required to tolerate the fetal semi-allograft and mammalian embryogenesis. Therefore, galectins play important roles in fetal development and placentation contributing to maternal and fetal health. This review discusses the expression and role of galectins during the course of pregnancy, with an emphasis on maternal immune adaptions and galectin-glycan interactions uncovered in the recent years. In addition, we summarize the galectin fingerprints associated with pathological gestation with particular focus on preeclampsia.

scholarly journals Manganese Induces Oxidative Stress, Redox State Unbalance and Disrupts Membrane Bound ATPases on Murine Neuroblastoma Cells In Vitro: Protective Role of Silymarin

2011 ◽  
Vol 36 (8) ◽  
pp. 1546-1557 ◽  
Author(s):  
Yassine Chtourou ◽  
Khaled Trabelsi ◽  
Hamadi Fetoui ◽  
Ghada Mkannez ◽  
Héla Kallel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Redox State ◽  
Neuroblastoma Cells ◽  
Protective Role ◽  
Murine Neuroblastoma ◽  
Membrane Bound

scholarly journals Histochemical identification of the vascular endothelial isoenzyme of alkaline phosphatase.

1989 ◽  
Vol 37 (12) ◽  
pp. 1893-1898 ◽  
Author(s):  
H F Zoellner ◽  
N Hunter
Keyword(s):  
Alkaline Phosphatase ◽  
Physiological Role ◽  
Freeze Substitution ◽  
Differential Sensitivity ◽  
Rat Tissues ◽  
Microvascular Endothelium ◽  
Membrane Bound ◽  
Specific Inhibitors

Alkaline phosphatase (AP) is a widely studied membrane bound ecto-enzyme with an extensive distribution in nature. Three major human isoenzymes have been defined and can be distinguished on the basis of their differential sensitivity to specific inhibitors. Despite the voluminous literature describing AP, the physiological role of this enzyme is unclear. Microvascular endothelium is strongly AP positive and may provide a convenient model for study of the role of AP in vitro. This report describes the use of freeze-substitution and high-resolution plastic embedding techniques to identify the isoenzyme of endothelial AP by quantitative analysis of the relative inhibition by specific inhibitors of AP, using human gingival tissues and a number of rat tissues. Endothelial AP is found to be the liver/bone/kidney isoenzyme, indicating kidney as a credible source of enzyme for further experimental work investigating the role of AP.

scholarly journals MicroRNA-34a induces endothelial progenitor cell senescence and impedes its angiogenesis via suppressing silent information regulator 1

2010 ◽  
Vol 299 (1) ◽  
pp. E110-E116 ◽  
Author(s):  
Ting Zhao ◽  
Jian Li ◽  
Alex F. Chen
Keyword(s):  
Progenitor Cell ◽  
Stem Cell Markers ◽  
Endothelial Progenitor ◽  
Cell Markers ◽  
Physiological Processes ◽  
Cycle Arrest ◽  
Forkhead Box ◽  
Silent Information Regulator 1

Endothelial progenitor cells (EPCs) play an important role in angiogenesis, which is essential for numerous physiological processes as well as tumor growth. Several microRNAs (miRNAs) have been reported to be involved in angiogenesis. MiR-34a, recently reported as a tumor suppressor, has been found to target silent information regulator 1 (Sirt1), leading to cell cycle arrest or apoptosis. However, the role of miR-34a in EPC-mediated angiogenesis was unknown. The present study tested the hypothesis that miR-34a inhibits EPC-mediated angiogenesis by inducing senescence via suppressing Sirt1. Bone marrow-derived EPCs from adult male Spraque-Dawley rats were used. Results of flow cytometry showed that EPCs after 7 days of culture expressed both stem cell markers CD34 and CD133 and endothelial cell markers VEGFR-2 (flk-1) and VE-cadherin. MiR-34a was expressed in normal EPCs, and overexpression of miR-34a via its mimic transfection significantly increased its expression and impaired in vitro EPC angiogenesis. MiR-34a overexpression led to a significantly increased EPC senescence, paralleled with an ∼40% Sirt1 reduction. Furthermore, knockdown of Sirt1 by its siRNA resulted in diminished EPC angiogenesis and increased senescence. Finally, overexpression of miR-34a increased the level of Sirt1 effector-acetylated forkhead box O transcription factors 1 (FoxO1), an effect mimicked in EPCs following Sirt1 knockdown. In conclusion, miR-34a impairs EPC-mediated angiogenesis by induction of senescence via inhibiting Sirt1.

scholarly journals Morphogenic Effects of Ezrin Require a Phosphorylation-Induced Transition from Oligomers to Monomers at the Plasma Membrane

2000 ◽  
Vol 150 (1) ◽  
pp. 193-204 ◽  
Author(s):  
Alexis Gautreau ◽  
Daniel Louvard ◽  
Monique Arpin
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Wild Type ◽  
Erm Proteins ◽  
Threonine Residue ◽  
Phosphorylation Event ◽  
Membrane Bound

ERM (ezrin, radixin, moesin) proteins act as linkers between the plasma membrane and the actin cytoskeleton. An interaction between their NH2- and COOH-terminal domains occurs intramolecularly in closed monomers and intermolecularly in head-to-tail oligomers. In vitro, phosphorylation of a conserved threonine residue (T567 in ezrin) in the COOH-terminal domain of ERM proteins disrupts this interaction. Here, we have analyzed the role of this phosphorylation event in vivo, by deriving stable clones producing wild-type, T567A, and T567D ezrin from LLC-PK1 epithelial cells. We found that T567A ezrin was poorly associated with the cytoskeleton, but was able to form oligomers. In contrast, T567D ezrin was associated with the cytoskeleton, but its distribution was shifted from oligomers to monomers at the membrane. Moreover, production of T567D ezrin induced the formation of lamellipodia, membrane ruffles, and tufts of microvilli. Both T567A and T567D ezrin affected the development of multicellular epithelial structures. Collectively, these results suggest that phosphorylation of ERM proteins on this conserved threonine regulates the transition from membrane-bound oligomers to active monomers, which induce and are part of actin-rich membrane projections.

Plastoquinone-9 biosynthesis in cyanobacteria differs from that in plants and involves a novel 4-hydroxybenzoate solanesyltransferase

2012 ◽  
Vol 442 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Radin Sadre ◽  
Christian Pfaff ◽  
Stephan Buchkremer
Keyword(s):  
Biosynthetic Pathway ◽  
In Vitro Assays ◽  
Transport Chain ◽  
In Vivo Labelling ◽  
Membrane Bound ◽  
Transformation Processes ◽  
Synechocystis Sp

PQ-9 (plastoquinone-9) has a central role in energy transformation processes in cyanobacteria by mediating electron transfer in both the photosynthetic as well as the respiratory electron transport chain. The present study provides evidence that the PQ-9 biosynthetic pathway in cyanobacteria differs substantially from that in plants. We identified 4-hydroxybenzoate as being the aromatic precursor for PQ-9 in Synechocystis sp. PCC6803, and in the present paper we report on the role of the membrane-bound 4-hydroxybenzoate solanesyltransferase, Slr0926, in PQ-9 biosynthesis and on the properties of the enzyme. The catalytic activity of Slr0926 was demonstrated by in vivo labelling experiments in Synechocystis sp., complementation studies in an Escherichia coli mutant with a defect in ubiquinone biosynthesis, and in vitro assays using the recombinant as well as the native enzyme. Although Slr0926 was highly specific for the prenyl acceptor substrate 4-hydroxybenzoate, it displayed a broad specificity with regard to the prenyl donor substrate and used not only solanesyl diphosphate, but also a number of shorter-chain prenyl diphosphates. In combination with in silico data, our results indicate that Slr0926 evolved from bacterial 4-hydroxybenzoate prenyltransferases catalysing prenylation in the course of ubiquinone biosynthesis.

Vectorial transport of proteins by membrane-bound ribosomes of nongrowing and growing Jerusalem artichoke tuber cells

1978 ◽  
Vol 56 (3) ◽  
pp. 167-173
Author(s):  
Joachim Sparkuhl ◽  
George Setterfield
Keyword(s):  
Reductase Activity ◽  
Jerusalem Artichoke ◽  
Jerusalem Artichoke Tuber ◽  
Protease Digestion ◽  
Associated Proteins ◽  
Membrane Bound ◽  
Nadh Cytochrome ◽  
Vectorial Transport

Both nongrowing (water-incubated) and growing (hormonally stimulated) Jerusalem artichoke tuber cells contain membrane-bound (mb) ribosomes. Using a rapid flotation procedure, a membrane fraction was prepared from both types of cells. This fraction was enriched in mb ribosomes, contained NADH cytochrome c reductase activity, had RNA:phospholipid and RNA:protein ratios similar to those reported for rough microsomes from animal tissues, and supported synthesis of preinitiated proteins in vitro. Using puromycin and detergent release, vectorial transport of labelled polypeptides was measured in the in vitro system. Of proteins made by mb ribosomes from nongrowing cells, only 12% remained associated with microsome membranes following chain termination. The comparable figure for proteins from mb ribosomes of growing tissue was 42%. The membrane-associated proteins were preferentially protected from protease digestion. Some possible reasons are suggested for the correlation between cell growth and the association of newly synthesized proteins with microsomes. The role of proteins synthesized by mb ribosomes but not vectorially transported, in both growing and nongrowing cells, is unknown.

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