scholarly journals Epigenetic repression of Wnt receptors in AD: a role for Sirtuin2-induced H4K16ac deacetylation of Frizzled1 and Frizzled7 promoters

2021 ◽  
Author(s):  
Ernest Palomer ◽  
Núria Martin-Flores ◽  
Sarah Jolly ◽  
Patricia Pascual-Vargas ◽  
Stefano Benvegnù ◽  
...  
Keyword(s):  
Synapse Formation ◽  
Late Onset ◽  
Wnt Signalling ◽  
Mrna Levels ◽  
Preclinical Ad ◽  
Synapse Degeneration ◽  
Epigenetic Repression

Growing evidence supports a role for deficient Wnt signalling in synapse degeneration in Alzheimer′s disease (AD). First, the Wnt antagonist DKK1 is elevated in the AD brain and is required for amyloidβ-induced synapse loss. Second, LRP6 Wnt co-receptor is required for synapse integrity and three variants of this receptor are linked to late-onset AD. However, the expression/role of other Wnt signalling components remain poorly explored in AD. Wnt receptors Frizzled1 (Fzd1), Fzd5, Fzd7 and Fzd9 are of particular interest due to their role in synapse formation and plasticity. Our analyses showed that FZD1 and FZD7 mRNA levels were reduced in the hippocampus of human preclinical AD (PAD) cases and in the hAPPNLGF/NLGF mouse model. This transcriptional downregulation was accompanied by reduced levels of the pro-transcriptional histone mark H4K16ac and a concomitant increase of its deacetylase Sirt2 at Fzd1 and Fzd7 promoters in AD. In vitro and in vivo inhibition of Sirt2 rescued Fzd1 and Fzd7 mRNA expression and H4K16ac levels at their promoters. In addition, we showed that Sirt2 recruitment to Fzd1 and Fzd7 promoters is dependent on FoxO1 activity in AD, thus acting as a co-repressor. Finally, we found reduced levels of inhibitory phosphorylation on Sirt2 in nuclear PAD samples and increased levels of the Sirt2 phosphatase PP2C, leading to hyperactive nuclear Sirt2 and favouring Fzd1 and Fzd7 repression in AD. Collectively, our findings define a novel role for nuclear hyperactivated Sirt2 in repressing Fzd1 and Fzd7 expression via H4K16ac deacetylation in AD. We propose Sirt2 as an attractive target to ameliorate AD pathology.

scholarly journals Role of Untranslated Regions of the Hemagglutinin-Neuraminidase Gene in Replication and Pathogenicity of Newcastle Disease Virus

2009 ◽  
Vol 83 (11) ◽  
pp. 5943-5946 ◽  
Author(s):  
Yongqi Yan ◽  
Subrat N. Rout ◽  
Shin-Hee Kim ◽  
Siba K. Samal
Keyword(s):  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Untranslated Regions ◽  
Mrna Levels ◽  
Recombinant Viruses ◽  
Virus Particles

ABSTRACT To determine the role of untranslated regions (UTRs) in replication and pathogenesis of Newcastle disease virus (NDV), we generated recombinant viruses with deletions in 5′ and 3′ UTRs of the HN mRNA. Deletion of any HN UTR did not noticeably affect in vitro replication of these viruses. However, complete deletion of the 5′ UTR of the HN gene decreased the HN mRNA levels and HN protein contents in virus particles, resulting in attenuation of the virus in chickens. This indicates that the 5′ UTR of HN mRNA plays an important role in replication and pathogenicity of NDV in vivo.

Nitric oxide enhancement of erythropoietin production in the isolated perfused rat kidney

1995 ◽  
Vol 269 (4) ◽  
pp. C917-C922 ◽  
Author(s):  
K. Yoshioka ◽  
J. W. Fisher
Keyword(s):  
Nitric Oxide ◽  
Rat Kidney ◽  
Mrna Levels ◽  
Isolated Perfused Rat Kidney ◽  
Intracellular Cgmp ◽  
Perfused Rat Kidney ◽  
Arterial Po2

We have previously reported that nitric oxide (NO) and guanosine 3',5'-cyclic monophosphate (cGMP) may be involved in the regulation of erythropoietin (Epo) production in response to hypoxia both in vivo and in vitro (20). In the present studies, we have used the isolated perfused rat kidney to assess the role of NO in oxygen sensing and Epo production. When arterial PO2 was reduced from 100 mmHg (normoxemic) to 30 mmHg (hypoxemic) in the perfusate of this system, perfusate levels of Epo were significantly increased. This hypoxia-induced increase in Epo production was significantly decreased by the addition of NG-nitro-L-arginine methyl ester (L-NAME; 1 mM) to the perfusates. Hypoxemic perfusion also produced a significant increase, and L-NAME significantly inhibited this increase, in intracellular cGMP levels in the kidney when compared with normoxemic perfused kidneys. Quantitative reverse transcription-polymerase chain reaction also revealed that hypoxemic perfusion produced significant increases in Epo mRNA levels in the kidney, which was blocked by L-NAME. Our findings further support an important role for the NO/cGMP system in hypoxic regulation of Epo production.

The role of ZNF395 in renal cell carcinoma proliferation, migration, and invasion.

2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 592-592 ◽  
Author(s):  
Chen Zhao ◽  
Christopher G. Wood ◽  
Jose A. Karam ◽  
Tapati Maity ◽  
Lei Wang
Keyword(s):  
Renal Cell Carcinoma ◽  
Tumor Growth ◽  
Cell Carcinoma ◽  
Cell Lines ◽  
Renal Cell ◽  
Migration And Invasion ◽  
Mrna Levels

592 Background: Zinc finger protein 395 (ZNF395) is frequently altered in several tumor types. However, the role of ZNF395 remains poorly studied in patients with clear cell renal cell carcinoma (RCC). In this study, we investigated the in vitro and in vivo role of ZNF395 in ccRCC. Methods: cBioPortal For Cancer Genomics was used to correlate the expression of ZNF395 with RCC patient clinical, pathological and molecular profiles. ZNF395 protein and mRNA levels were studied in several RCC cell lines in vitro. Subsequently, ZNF395 knockdown was performed in 786-O and UMRC3 RCC cells and overexpression was done in Caki-1 and 769-P RCC cells. We then evaluated ZNF395 modulation in these cell lines by in vitro MTT, migration and invasion assays. Finally, we studied the effect of ZNF395 knockout and overexpression in vivo using SCID xenograft models. Results: Patients with higher expression of ZNF395 experienced longer disease-free survival and overall survival. Using in vitro models, we confirmed that knockdown of ZNF395 decreased ZNF395 expression, and increased proliferation, migration and invasiveness of 786-O and UMRC3, while overexpression of ZNF395 increased ZNF395 expression, and reduced proliferation, migration and invasiveness of Caki-1 and 769-P. Using in vivo mouse models, knockdown of ZNF395 expression in 786-O promoted tumor growth while its overexpression in Caki-1 resulted in tumor growth inhibition. We are currently performing experiments to understand the process by which ZNF395 regulates ccRCC pathogenesis. Conclusions: Our data support the role of ZNF395 as an important tumor suppressor gene in the pathogenesis of RCC.

MiR-134, Mediated by IRF1, Suppresses Tumorigenesis and Progression by Targeting VEGFA and MYCN in Osteosarcoma

2020 ◽  
Vol 20 (10) ◽  
pp. 1197-1208
Author(s):  
Zhuo Ma ◽  
Kai Li ◽  
Peng Chen ◽  
Qizheng Pan ◽  
Xuyang Li ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Lines ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Mrna Levels ◽  
Invasion And Migration ◽  
And Migration

Background: Osteosarcoma (OS) is a prevalent primary bone malignancy and its distal metastasis remains the main cause of mortality in OS patients. MicroRNAs (miRNAs) play critical roles during cancer metastasis. Objective: Thus, elucidating the role of miRNA dysregulation in OS metastasis may provide novel therapeutic targets. Methods: The previous study found a low miR-134 expression level in the OS specimens compared with paracancer tissues. Overexpression of miR-134 stable cell lines was established. Cell viability assay, cell invasion and migration assay and apoptosis assay were performed to evaluate the role of miR-134 in OS in vitro. Results: We found that miR-134 overexpression inhibits cell proliferation, migration and invasion, and induces cell apoptosis in both MG63 and Saos-2 cell lines. Mechanistically, miR-134 targets the 3'-UTR of VEGFA and MYCN mRNA to silence its translation, which was confirmed by luciferase-reporter assay. The real-time PCR analysis illustrated that miR-134 overexpression decreases VEGFA and MYCN mRNA levels. Additionally, the overexpression of VEGFA or MYCN can partly attenuate the effects of miR-134 on OS cell migration and viability. Furthermore, the overexpression of miR-134 dramatically inhibits tumor growth in the human OS cell line xenograft mouse model in vivo. Moreover, bioinformatic and luciferase assays indicate that the expression of miR-134 is regulated by Interferon Regulatory Factor (IRF1), which binds to its promoter and activates miR-134 expression. Conclusion: Our study demonstrates that IRF1 is a key player in the transcriptional control of miR-134, and it inhibits cell proliferation, invasion and migration in vitro and in vivo via targeting VEGFA and MYCN.

Role of the TNF pathway in the progression of diabetic nephropathy in KK-Ay mice

2014 ◽  
Vol 306 (11) ◽  
pp. F1335-F1347 ◽  
Author(s):  
Keisuke Omote ◽  
Tomohito Gohda ◽  
Maki Murakoshi ◽  
Yu Sasaki ◽  
Saiko Kazuno ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Early Stage ◽  
Mrna Levels ◽  
Monocyte Chemoattractant Protein 1 ◽  
Protein Levels ◽  
Tnf Α ◽  
Soluble Tnf Receptor

Chronic inflammation promotes the progression of diabetic nephropathy (DN). However, the role of TNF-α remains unclear. The objectives of the present study were to examine whether TNF-α inhibition with a soluble TNF receptor (TNFR)2 fusion protein, i.e., etanercept (ETN), improves the early stage of DN in the type 2 diabetic model of the KK-Ay mouse and to also investigate which TNF pathway, TNFR1 or TNFR2, is predominantly involved in the progression of this disease. ETN was injected intraperitoneally into mice for 8 wk. Renal damage was evaluated by immunohistochemistry, Western blot analysis, and/or real-time PCR. In vitro, mouse tubular proximal cells were stimulated by TNF-α and/or high glucose (HG) and treated with ETN. ETN dramatically improved not only albuminuria but also glycemic control. Renal mRNA and/or protein levels of TNFR2, but not TNF-α and TNFR1, in ETN-treated KK-Ay mice were significantly decreased compared with untreated KK-Ay mice. mRNA levels of ICAM-1, VCAM-1, and monocyte chemoattractant protein-1 and the number of F4/80-positive cells were all decreased after treatment. Numbers of cleaved caspase-3- and TUNEL-positive cells in untreated mice were very few and were not different from ETN-treated mice. In vitro, stimulation with TNF-α or HG markedly increased both mRNA levels of TNFRs, unlike in the in vivo case. Furthermore, ETN partly recovered TNF-α-induced but not HG-induced TNFR mRNA levels. In conclusion, it appears that ETN may improve the progression of the early stage of DN predominantly through inhibition of the anti-inflammatory action of the TNF-α-TNFR2 pathway.

scholarly journals Knockout of myoc Provides Evidence for the Role of Myocilin in Zebrafish Sex Determination Associated with Wnt Signalling Downregulation

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 98
Author(s):  
Raquel Atienzar-Aroca ◽  
José-Daniel Aroca-Aguilar ◽  
Susana Alexandre-Moreno ◽  
Jesús-José Ferre-Fernández ◽  
Juan-Manuel Bonet-Fernández ◽  
...  
Keyword(s):  
Sex Determination ◽  
Anterior Segment ◽  
Premature Termination Codon ◽  
Wnt Signalling ◽  
Mrna Levels ◽  
Loss Of Function ◽  
Ocular Tissues ◽  
Key Factor

Myocilin is a secreted glycoprotein with a poorly understood biological function and it is mainly known as the first glaucoma gene. To explore the normal role of this protein in vivo we developed a myoc knockout (KO) zebrafish line using CRISPR/Cas9 genome editing. This line carries a homozygous variant (c.236_239delinsAAAGGGGAAGGGGA) that is predicted to result in a loss-of-function of the protein because of a premature termination codon p.(V75EfsX60) that resulted in a significant reduction of myoc mRNA levels. Immunohistochemistry showed the presence of myocilin in wild-type embryonic (96 h post-fertilization) anterior segment eye structures and caudal muscles. The protein was also detected in different adult ocular and non-ocular tissues. No gross macroscopic or microscopic alterations were identified in the KO zebrafish, but, remarkably, we observed absence of females among the adult KO animals and apoptosis in the immature juvenile gonad (28 dpf) of these animals, which is characteristic of male development. Transcriptomic analysis showed that adult KO males overexpressed key genes involved in male sex determination and presented differentially expressed Wnt signalling genes. These results show that myocilin is required for ovary differentiation in zebrafish and provides in vivo support for the role of myocilin as a Wnt signalling pathway modulator. In summary, this myoc KO zebrafish line can be useful to investigate the elusive function of this protein, and it provides evidence for the unexpected function of myocilin as a key factor in zebrafish sex determination.

C-Cbl Regulates c-Mpl Receptor Trafficking and Its Internalization

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2388-2388
Author(s):  
Sebastian Jonas Saur ◽  
Melanie Märklin ◽  
Manuela Ganser ◽  
Kyle Hoehn ◽  
James E David ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Plasma Levels ◽  
Thrombus Formation ◽  
Surface Expression ◽  
Mrna Levels ◽  
Wild Type ◽  
Primary Mouse

Abstract Megakaryopoiesis is controlled by a variety of hematopoietic growth factors and cytokines in order to maintain physiological levels of circulating platelets. Thrombopoietin (TPO) signalling via its receptor c-Mpl is a key regulator of megakaryopoiesis driving megakaryocyte differentiation, promoting endomitosis and proplatelet formation. Therefore TPO/c-Mpl signalling needs to be tightly regulated to maintain physiological megakaryopoiesis. One of the most effective mechanisms to permanently disable activated signalling proteins is by targeted degradation via lysosomes or proteasomes. Previous studies have identified c-Cbl as an E3 ligase responsible for the ubiquitination of c-Mpl in cell lines. In this study, we investigated the mechanisms of TPO-mediated c-Mpl degradation in primary mouse cells. In order to determine the potential role of c-Cbl in murine megakaryopoiesis we used a conditional PF4-Cre c-Cbl knockout (ko) mouse model to specifically delete c-Cbl in the megakaryocytic lineage. Megakaryocytes were generated in vitro by culturing bone marrow from WT and PF4-Cre/c-Cbl-floxed (c-Cbl ko) lines for 72 hrs in the presence of rmTPO. C-Cbl ko mice showed significant bone marrow megakaryocyte hyperplasia, however megakaryocyte numbers in the spleen remained unchanged. Platelets counts were significantly elevated as compared to control mice (1.2 x106 vs. 1.7x106 p=0.0001) and in addition, the platelets from the c-Cbl ko mouse strain were of significantly smaller size (43 vs. 38 fL, p=0.0022). Using a method of in vivo double labelling of platelets, we were able to simultaneously follow the survival of both the entire population of platelets and new platelets which were generated during the last 24 hours. There were more new platelets produced within a 24 h period in the c-Cbl ko mice although the half-life of platelets was similar in the both cohorts. Although c-Cbl ko mice exhibited thrombocytosis, they showed a severe defect in thrombus formation using an in vivo thrombus formation model with Fe3Cl. TPO plasma levels, known to be inversely regulated by circulating platelet numbers, were surprisingly increased (250 vs. 420 pg/ml, p=0.005) in the c-Cbl ko mice. There was no difference in liver mRNA levels in the two cohorts. We therefore looked at c-Mpl protein and mRNA expression in megakaryocytes and found c-Cbl ko mice to express more c-Mpl compared with wild type controls. Surprisingly, we found c-Mpl surface expression to be reduced and internalization of the receptor significantly impaired following TPO stimulation in c-Cbl ko mice. Incubating platelets in vitro with TPO for 2 hours to evaluate the TPO uptake capacity of platelets, we found c-Cbl ko platelets to show a severe uptake defect compared with wild type control platelets. Taken together, we have successfully ablated c-Cbl specifically from the megakaryocyte lineage and demonstrated that this has profound effects on platelet counts and size. In addition, we showed that c-Cbl ablation leads to reduced c-Mpl surface expression and impaired internalization, which culminates in increased TPO plasma levels causing increased megakaryopoiesis in the c-Cbl ko mice. In summary, our data enhance our understanding of the regulation of TPO signalling and the physiological role of c-Cbl in the megakaryocytic lineage. Disclosures No relevant conflicts of interest to declare.

scholarly journals Hormonal treatment, mild cognitive impairment and Alzheimer's disease

2008 ◽  
Vol 20 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Joanne Ryan ◽  
Jaqueline Scali ◽  
Isabelle Carriere ◽  
Karen Ritchie ◽  
Marie-Laure Ancelin
Keyword(s):  
Risk Factors ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Verbal Memory ◽  
Late Onset ◽  
Controlled Trial ◽  
Hormonal Changes

ABSTRACTA plethora of in vitro and in vivo studies have supported the neuroprotective role of estrogens and their impact on the neurotransmitter systems implicated in cognition. Recent hormonal replacement therapy (HRT) trials in non-demented postmenopausal women suggest a temporary positive effect (notably on verbal memory), and four meta-analyses converge to suggest a possible protective effect in relation to Alzheimer's disease (reducing risk by 29 to 44%). However, data from the only large randomized controlled trial published to date, the Women's Health Initiative Memory Study, did not confirm these observations and have even suggested an increase in dementia risk for women using HRT compared to controls. Apart from methodological differences, one key shortcoming of this trial has probably been the focus on late-onset (postmenopausal) hormonal changes, i.e. at a time when the neurodegenerative process has already begun and without taking into account individual lifetime exposure to hormone variability. Multifactorial models based on an exhaustive view of all hormonal events throughout the reproductive life (rather than on a specific exposure to a given steroid) together with other risk factors (notably genetic risk factors related to estrogen receptor polymorphisms) should be explored to clarify the role of hormonal risk factors, or protective factors for cognitive dysfunction and dementia.

scholarly journals EphrinB1 modulates glutamatergic inputs into POMC neurons and controls glucose homeostasis

2020 ◽  
Author(s):  
Manon Gervais ◽  
Alexandre Picard ◽  
Bernard Thorens ◽  
Sophie Croizier
Keyword(s):  
Insulin Secretion ◽  
Glucose Homeostasis ◽  
Synapse Formation ◽  
Brain Regions ◽  
Excitatory Input ◽  
Nerve Activity ◽  
Input Amount

AbstractProopiomelanocortin (POMC) neurons are major regulators of energy balance and glucose homeostasis. In addition to being regulated by hormones and nutrients, POMC neurons are controlled by glutamatergic input originating from multiple brain regions. However, the factors involved in the formation of glutamatergic inputs and how they contribute to bodily functions remain largely unknown. Here, we show that during the development of glutamatergic inputs, POMC neurons exhibit enriched expression of the Efnb1 (EphrinB1) and Efnb2 (EphrinB2) genes, which are known to control excitatory synapse formation. In vitro silencing and in vivo loss of Efnb1 or Efnb2 in POMC neurons decreases the amount of glutamatergic inputs into these neurons. We found that mice lacking Efnb1 in POMC neurons display impaired glucose tolerance due to blunted vagus nerve activity and decreased insulin secretion. However, mice lacking Efnb2 in POMC neurons showed no deregulation of insulin secretion and only mild alterations in feeding behavior and gluconeogenesis. Collectively, our data demonstrate the role of ephrins in controlling excitatory input amount into POMC neurons and show an isotype-specific role of ephrins on the regulation of glucose homeostasis and feeding.

Macrophage Inflammatory Protein (MIP)-3α/CCL20 and Its Receptor CCR6 Are Overexpressed in the Bone Microenvironment and Involved in Osteoclast Formation in Multiple Myeloma Patients.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3510-3510 ◽  
Author(s):  
Nicola Giuliani ◽  
Gina Lisignoli ◽  
Sara Tagliaferri ◽  
Mirca Lazzaretti ◽  
Francesca Morandi ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Osteoclast Formation ◽  
Bone Lesions ◽  
Mrna Levels ◽  
Bone Microenvironment ◽  
Inflammatory Protein ◽  
Macrophage Inflammatory Protein

Abstract Osteoclast (OC) activation in multiple myeloma (MM) is primarily due to the imbalance of the critical osteoclastogenic system RANKL/OPG in the bone microenvironment. Recent evidences indicate that chemokines, small chemoattractant proteins involved in cancer cell homing, may contribute to osteoclast formation and activation. However, whereas the role of the chemokine macrophage inflammatory protein (MIP)-1α in MM-induced OC activation is well established, the involvement of other chemokines is not known. In this study, we evaluated the potential role of MIP-3α/CCL20 and its receptor CCR6 in the pathophysiology of OC formation and osteolytic lesions in MM. First the effect of MIP-3α/CCL20 on in vitro osteoclast formation by peripheral monocytes was evaluated. (MIP)-3α/CCL20 significantly increased both the number of multinucleated TRAP+ OCs and RANK+ OC progenitor cells in presence of RANKL. In addition we found that (MIP)-3α/CCL20 increases RANKL mRNA levels in both human osteoblastic (OB) and bone marrow (BM) osteoprogenitor cells (preOB). Following, the potential production of (MIP)-3α/CCL20 by human MM cell lines (HMCLs) and fresh purified CD138+ MM cells was also checked. Significant levels of (MIP)-3α/CCL20 were detected in one out of nine HMCLs tested and in about 10% of purified MM cells by ELISA and immunohystochemistry. On the other hand we found that MM cells up-regulated (MIP)-3α/CCL20 secretion, in OB/PreOB cells and in OCs as well as its receptor CCR6 in OCs in co-culture systems in presence of a transwell insert. Among potential soluble factors involved in the up-regulation of MIP-3α/CCL20 by MM cells we found that IL-1β and TNFα together stimulate MIP-3α/CCL20 production in both OB and PreOB. The role of MIP-3α/CCL20 in OC activation by MM cells was finally demonstrated by finding that both blocking anti-(MIP)-3α/CCL20 and anti-CCR6 Abs. but not anti-IgG control significantly decreased OC formation induced by the conditioned medium of MM cells co-cultured with OB and OC, respectively. This chemokine system was further studied in vivo in MM patients. MIP-3α/CCL20 levels were detected in the BM plasma of MGUS subjects (n°=16) and in MM (n°=52) patients at the diagnosis in relationship with the presence of bone lesions (osteolytic n°= 32; non-osteolytic: n°=20). Significant higher MIP-3α/CCL20 levels were detected in MM patients vs. MGUS (mean ± SD: 51.9±2 vs. 21±3 pg/mL; p=0.01) and in MM osteolytic patients vs. non-osteolytic ones (mean ± SD: 70.8±5.9 vs. 13.8±1.1 pg/mL; p=0.001). Interestingly, no significant differences were observed between MGUS and non-osteolytic MM patients. By immunohystochemistry performed on BM biopsies, we consistently found that MIP-3α/CCL20 was over-expressed in OBs in osteolytic MM patients as compared to non-osteolytic ones. In addition we found that OCs showed a strong CCR6 staining in the areas with an increased number of OCs. In conclusion our data indicate that (MIP)-3α/CCL20 its receptor CCR6 are up-regulated in bone microenvironment by MM cells and involved in osteoclast formation and bone lesions in MM patients.

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