Post-receptor IGF1 insensitivity restricted to the MAPK pathway in a Silver–Russell syndrome patient with hypomethylation at the imprinting control region on chromosome 11

2012 ◽  
Vol 166 (3) ◽  
pp. 543-550 ◽  
Author(s):  
Luciana R Montenegro ◽  
Andrea C Leal ◽  
Debora C Coutinho ◽  
Helena P L Valassi ◽  
Mirian Y Nishi ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Chromosome 11 ◽  
Gene Expressions ◽  
Gh Treatment ◽  
Poor Growth ◽  
Mapk Activation ◽  
Silver Russell Syndrome

BackgroundHypomethylation of the paternal imprinting center region 1 (ICR1) is the most frequent molecular cause of Silver–Russell syndrome (SRS). Clinical evidence suggests that patients with this epimutation have mild IGF1 insensitivity.ObjectiveTo assess in vitro IGF1 action in fibroblast culture from a patient with SRS and IGF1 insensitivity.MethodsFibroblast cultures from one patient with SRS due to ICR1 demethylation and controls were established. The SRS patient has severe growth failure, elevated IGF1 level, and poor growth rate during human recombinant GH treatment. IGF1 action was assessed by cell proliferation, AKT, and p42/44-MAPK phosphorylation. Gene expression was determined by real-time PCR.ResultsDespite normal IGF1R sequence and expression, fibroblast proliferation induced by IGF1 was 50% lower in SRS fibroblasts in comparison with controls. IGF1 and insulin promoted a p42/44-MAPK activation in SRS fibroblasts 40 and 36%, respectively, lower than that in control fibroblasts. On the other hand, p42/44-MAPK activation induced by EGF stimulation was only slightly reduced (75% in SRS fibroblasts in comparison with control), suggesting a general impairment in MAPK pathway with a greater impairment of the stimulation induced by insulin and IGF1 than by EGF. A PCR array analysis disclosed a defect in MAPK pathway characterized by an increase in DUSP4 and MEF2C gene expressions in patient fibroblasts.ConclusionA post-receptor IGF1 insensitivity was characterized in one patient with SRS and ICR1 hypomethylation. Although based on one unique severely affected patient, these results raise an intriguing mechanism to explain the postnatal growth impairment observed in SRS patients that needs confirmation in larger cohorts.

scholarly journals Comparison of Oxidative Status of Human Milk, Human Milk Fortifiers and Preterm Infant Formulas

Foods ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 458 ◽  
Author(s):  
Pozzo ◽  
Cirrincione ◽  
Russo ◽  
Karamać ◽  
Amarowicz ◽  
...  
Keyword(s):  
Human Milk ◽  
Antioxidant Capacity ◽  
Preterm Infant ◽  
Bovine Milk ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Infant Formulas ◽  
Low Birth Weight Infants ◽  
Multivariate Statistical

Preterm and low birth weight infants require specific nutrition to overcome the accumulated growth deficit, and to prevent morbidities related to postnatal growth failure. In order to guarantee an adequate nutrient-intake, mother’s own milk, when available, or donor human milk, are usually fortified with additional nutrients, in particular proteins. Fortification with processed ingredients may result in additional intake in oxidative compounds, deriving from extensive heat treatments, that are applied during processing. The aim of the present work was to compare the in vitro antioxidant activity and oxidative compound content conveyed by different preterm infant foods and fortifiers, namely raw and pasteurized human milk, two different preterm infant formulas, three bovine milk-based fortifiers and two experimental donkey milk-based fortifiers. Univariate and multivariate statistical analyses revealed significant differences between the different products. The use of human milk minimizes the intake of dietary oxidative compound in comparison to infant formulas, irrespective of pasteurization or fortification, especially as far as malondialdehyde content is concerned. The addition of fortifiers to human milk increases its antioxidant capacity, and the choice of the protein source (hydrolysed vs. whole proteins) differently impacted the resulting total antioxidant capacity of the diet.

scholarly journals Postnatal Growth Failure, Short Life Span, and Early Onset of Cellular Senescence and Subsequent Immortalization in Mice Lacking the Xeroderma Pigmentosum Group G Gene

1999 ◽  
Vol 19 (3) ◽  
pp. 2366-2372 ◽  
Author(s):  
Yoshi-Nobu Harada ◽  
Naoko Shiomi ◽  
Manabu Koike ◽  
Masahito Ikawa ◽  
Masaru Okabe ◽  
...  
Keyword(s):  
Early Onset ◽  
Xeroderma Pigmentosum ◽  
Excision Repair ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Additional Function ◽  
Xeroderma Pigmentosum Group G ◽  
Postnatal Growth Failure ◽  
Deficient Mice

ABSTRACT The xeroderma pigmentosum group G (XP-G) gene (XPG) encodes a structure-specific DNA endonuclease that functions in nucleotide excision repair (NER). XP-G patients show various symptoms, ranging from mild cutaneous abnormalities to severe dermatological impairments. In some cases, patients exhibit growth failure and life-shortening and neurological dysfunctions, which are characteristics of Cockayne syndrome (CS). The known XPG protein function as the 3′ nuclease in NER, however, cannot explain the development of CS in certain XP-G patients. To gain an insight into the functions of the XPG protein, we have generated and examined mice lacking xpg (the mouse counterpart of the humanXPG gene) alleles. The xpg-deficient mice exhibited postnatal growth failure and underwent premature death. SinceXPA-deficient mice, which are totally defective in NER, do not show such symptoms, our data indicate that XPG performs an additional function(s) besides its role in NER. Our in vitro studies showed that primary embryonic fibroblasts isolated from thexpg-deficient mice underwent premature senescence and exhibited the early onset of immortalization and accumulation of p53.

scholarly journals Ethanol-Induced Lymphatic Endothelial Cell Permeability via MAP-Kinase Regulation

2021 ◽  
Author(s):  
Matthew Herrera ◽  
Patricia Molina ◽  
Flavia M. Souza-Smith
Keyword(s):  
Endothelial Cell ◽  
Cell Viability ◽  
Barrier Function ◽  
Protein Localization ◽  
Cell Monolayer ◽  
Lymphatic Endothelial Cell ◽  
Cell Permeability ◽  
Gene Expressions ◽  
Mapk Activation

Chronic alcohol alters the immune system enhancing the susceptibility to inflammation, bacterial, and viral infections in alcohol users. We have shown that alcohol causes increased permeability of mesenteric lymphatic vessels in alcohol fed rats. The mechanisms of alcohol-induced lymphatic leakage are unknown. Endothelial cell monolayer permeability is controlled by junctional proteins complexes called tight junctions (TJ) and adherens junctions (AJ), and each can be regulated by MAPK activation. We hypothesize that ethanol induces lymphatic endothelial cell (LEC) permeability via disruption of LEC TJ through MAPK activation. An in vitro model of rat LECs was used. Ethanol-supplemented medium was added at concentrations of 0, 25, and 50 mM to confluent cells. Resistance-based barrier function, transwell permeability, cell viability, TJ, AJ, and MAPK protein activity, TJ and AJ gene expressions, and the role of p38 MAPK in barrier function regulation were measured. Ethanol increased the permeability of LECs compared to controls that was not associated with decreased cell viability. LECs treated with 50 mM ethanol showed an increase in phosphorylated levels of p38. No significant changes in TJ and AJ gene or protein expressions were observed after ethanol treatment. p38 inhibition prevented ethanol-induced increases in permeability. These findings suggest that p38 may play a role in the regulation of ethanol-induced LEC permeability, but altered permeability may not be associated with decreased TJ or AJ protein expression. Further investigation into junctional protein localization is needed to better understand the effects of ethanol on lymphatic endothelial cell-to-cell contacts and hyperpermeability.

scholarly journals Persistent ERK/MAPK Activation Promotes Lactotrope Differentiation and Diminishes Tumorigenic Phenotype

2014 ◽  
Vol 28 (12) ◽  
pp. 1999-2011 ◽  
Author(s):  
Allyson Booth ◽  
Tammy Trudeau ◽  
Crystal Gomez ◽  
M. Scott Lucia ◽  
Arthur Gutierrez-Hartmann
Keyword(s):  
Mapk Pathway ◽  
Expression System ◽  
Mapk Signaling ◽  
Tumor Formation ◽  
Cell Phenotype ◽  
Mapk Activation

The signaling pathways that govern the lactotrope-specific differentiated phenotype, and those that control lactotrope proliferation in both physiological and pathological lactotrope expansion, are poorly understood. Moreover, the specific role of MAPK signaling in lactotrope proliferation vs differentiation, whether activated phosphorylated MAPK is sufficient for prolactinoma tumor formation remain unknown. Given that oncogenic Ras mutations and persistently activated phosphorylated MAPK are found in human tumors, including prolactinomas and other pituitary tumors, a better understanding of the role of MAPK in lactotrope biology is required. Here we directly examined the role of persistent Ras/MAPK signaling in differentiation, proliferation, and tumorigenesis of rat pituitary somatolactotrope GH4 cells. We stimulated Ras/MAPK signaling in a persistent, long-term manner (over 6 d) in GH4 cells using two distinct approaches: 1) a doxycycline-inducible, oncogenic V12Ras expression system; and 2) continuous addition of exogenous epidermal growth factor. We find that long-term activation of the Ras/MAPK pathway over 6 days promotes differentiation of the bihormonal somatolactotrope GH4 precursor cell into a prolactin-secreting, lactotrope cell phenotype in vitro and in vivo with GH4 cell xenograft tumors. Furthermore, we show that persistent activation of the Ras/MAPK pathway not only fails to promote cell proliferation, but also diminishes tumorigenic characteristics in GH4 cells in vitro and in vivo. These data demonstrate that activated MAPK promotes differentiation and is not sufficient to drive tumorigenesis, suggesting that pituitary lactotrope tumor cells have the ability to evade the tumorigenic fate that is often associated with Ras/MAPK activation.

scholarly journals Growth Hormone Receptor (Ghr) 6ω Pseudoexon Activation: A Novel Cause Of Severe Growth Hormone Insensitivity (Ghi)

2021 ◽  
Author(s):  
Emily Cottrell ◽  
Avinaash Maharaj ◽  
Jack Williams ◽  
Sumana Chatterjee ◽  
Grazia Cirillo ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Hormone Receptor ◽  
Growth Failure ◽  
Index Patient ◽  
Postnatal Growth ◽  
The Novel ◽  
Growth Hormone Insensitivity ◽  
In Vitro Splicing ◽  
The Impact

Abstract Context Severe forms of Growth Hormone Insensitivity (GHI) are characterized by extreme short stature, dysmorphism and metabolic anomalies. Objective Identification of the genetic cause of growth failure in 3 ‘classical’ GHI subjects. Design A novel intronic GHR variant was identified, and in vitro splicing assays confirmed aberrant splicing. A 6Ω pseudoexon GHR vector and patient fibroblast analysis assessed the consequences of the novel pseudoexon inclusion and the impact on GHR function. Results We identified a novel homozygous intronic GHR variant (g.5:42700940T>G, c.618 + 836T> G), 44bp downstream of the previously recognized intronic 6Ψ GHR pseudoexon mutation in the index patient. Two siblings also harbored the novel intronic 6Ω pseudoexon GHR variant in compound heterozygosity with the known GHR c.181C>T (R43X) mutation. In vitro splicing analysis confirmed inclusion of a 151bp mutant 6Ω pseudoexon not identified in wild-type constructs. Inclusion of the 6Ω pseudoexon causes a frameshift resulting in a non-functional truncated GHR lacking the transmembrane and intracellular domains. The truncated 6Ω pseudoexon protein demonstrated extracellular accumulation and diminished activation of STAT5B signaling following growth hormone stimulation. Conclusion Novel GHR 6Ω pseudoexon inclusion results in loss of GHR function consistent with a severe GHI phenotype. This represents a novel mechanism of Laron syndrome and is the first deep intronic variant identified causing severe postnatal growth failure. The 2 kindreds originate from the same town in Campania, Southern Italy, implying common ancestry. Our findings highlight the importance of studying variation in deep intronic regions as a cause of monogenic disorders.

scholarly journals Molecular and clinical analyses of two patients with UPD(16)mat detected by screening 94 patients with Silver-Russell syndrome phenotype of unknown aetiology

2018 ◽  
Vol 56 (6) ◽  
pp. 413-418 ◽  
Author(s):  
Takanobu Inoue ◽  
Hideaki Yagasaki ◽  
Junko Nishioka ◽  
Akie Nakamura ◽  
Keiko Matsubara ◽  
...  
Keyword(s):  
Snp Array ◽  
Uniparental Disomy ◽  
Gene Mutations ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Differentially Methylated Region ◽  
Unknown Aetiology ◽  
Chromosome 16 ◽  
Maternal Uniparental Disomy ◽  
Silver Russell Syndrome

BackgroundRecently, a patient with maternal uniparental disomy of chromosome 16 (UPD(16)mat) presenting with Silver-Russell syndrome (SRS) phenotype was reported. SRS is characterised by growth failure and dysmorphic features.ObjectiveTo clarify the prevalence of UPD(16)mat in aetiology-unknown patients with SRS phenotype and phenotypic differences between UPD(16)mat and SRS.MethodsWe studied 94 patients with SRS phenotype of unknown aetiology. Sixty-three satisfied the Netchine-Harbison clinical scoring system (NH-CSS) criteria, and 25 out of 63 patients showed both protruding forehead and relative macrocephaly (clinical SRS). The remaining 31 patients met only three NH-CSS criteria, but were clinically suspected as having SRS. To detect UPD(16)mat, we performed methylation analysis for the ZNF597:TSS-differentially methylated region (DMR) on chromosome 16 and subsequently performed microsatellite, SNP array and exome analyses in the patients with hypomethylated ZNF597:TSS-DMR.ResultsWe identified two patients (2.1%) with a mixture of maternal isodisomy and heterodisomy of chromosome 16 in 94 aetiology-unknown patients with SRS phenotype. Both patients exhibited preterm birth and prenatal and postnatal growth failure. The male patient had ventricular septal defect and hypospadias. Whole-exome sequencing detected no gene mutations related to their phenotypes.ConclusionWe suggest considering genetic testing for UPD(16)mat in SRS phenotypic patients without known aetiology.

scholarly journals Genome-wide methylation analysis in Silver–Russell syndrome, Temple syndrome, and Prader–Willi syndrome

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Kaori Hara-Isono ◽  
Keiko Matsubara ◽  
Tomoko Fuke ◽  
Kazuki Yamazawa ◽  
Kazuhito Satou ◽  
...  
Keyword(s):  
Clustering Analysis ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Methylation Pattern ◽  
Prader Willi Syndrome ◽  
Methylation Analysis ◽  
Genome Wide ◽  
Temple Syndrome ◽  
Methylation Patterns ◽  
Silver Russell Syndrome

Abstract Background Imprinting disorders (IDs) show overlapping phenotypes, particularly in Silver–Russell syndrome (SRS), Temple syndrome (TS14), and Prader–Willi syndrome (PWS). These three IDs include fetal and postnatal growth failure, feeding difficulty, and muscular hypotonia as major clinical features. However, the mechanism that causes overlapping phenotypes has not been clarified. To investigate the presence or absence of methylation signatures associated with overlapping phenotypes, we performed genome-wide methylation analysis (GWMA). Results GWMA was carried out on 36 patients with three IDs (SRS [n = 16], TS14 [n = 7], PWS [n = 13]) and 11 child controls using HumanMethylation450 BeadChip including 475,000 CpG sites across the human genome. To reveal an aberrantly methylated region shared by SRS, TS14, and PWS groups, we compared genome-wide methylation data of the three groups with those of control subjects. All the identified regions were known as SRS-, TS14-, and PWS-related imprinting-associated differentially methylated regions (iDMRs), and there was no hypermethylated or hypomethylated region shared by different ID groups. To examine the methylation pattern shared by SRS, TS14, and PWS groups, we performed clustering analysis based on GWMA data. The result focusing on 620 probes at the 62 known iDMRs (except for SRS-, TS14-, and PWS-related iDMRs) classified patients into two categories: (1) category A, grossly normal methylation patterns mainly consisting of SRS group patients; and (2) category B, broad and mild hypermethylation patterns mainly consisting of TS14 and PWS group patients. However, we found no obvious relationship between these methylation patterns and phenotypes of patients. Conclusions GWMA in three IDs found no methylation signatures shared by SRS, TS14, and PWS groups. Although clustering analysis showed similar mild hypermethylation patterns in TS14 and PWS groups, further study is needed to clarify the effect of methylation patterns on the overlapping phenotypes.

The Diagnostic Value of IGF-2 and the IGF/IGFBP-3 System in Silver-Russell Syndrome

2017 ◽  
Vol 88 (3-4) ◽  
pp. 201-207 ◽  
Author(s):  
Gerhard Binder ◽  
Thomas Eggermann ◽  
Karin Weber ◽  
Nawfel Ferrand ◽  
Roland Schweizer
Keyword(s):  
Uniparental Disomy ◽  
Clinical Signs ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Diagnostic Value ◽  
Maternal Uniparental Disomy ◽  
Short Children ◽  
Postnatal Growth Failure ◽  
Silver Russell Syndrome ◽  
Igfbp 3

Background/Aims: Recently, we have described a family of 4 members presenting with intrauterine and postnatal growth failure, low IGF-2 levels, and signs of Silver-Russell syndrome (SRS) who carried a genomic IGF2 mutation. Here, we assess the value of IGF-2 in relation to SRS. Methods: We collected data from 48 SRS children and 48 short children born small for gestational age (SGA) seen at our center. The SRS children were 4.6 ± 2.0 years of age, and the SGA children were 4.8 ± 1.8 years of age. All patients were prepubertal and growth hormone naive. An 11p15 ICR1 loss of methylation (11p15LOM) was present in 22, maternal uniparental disomy of chromosome 7 (upd(7)mat) in 7, and IGF2 genomic mutation (IGF2mut) in 3 patients. Growth factors were measured by in-house radioimmunoassays. Results: The median IGF-2 standard deviation scores (SDSs) were: IGF2mut –1.75, upd(7)mat –1.69, nonsyndromic SGA –1.52, 11p15LOM –0.61, and clinical (tested negative) –0.55. The median IGF-2:IGF-1 concentration ratio was 2.57 in IGF2mut compared to 5.44 in 11p15LOM (p = 0.036), 7.84 in clinical, and 7.98 in upd(7)mat. Upd(7)mat patients had significantly lower IGF-1 and IGFBP-3 SDSs than patients with 11p15LOM (p ≤ 0.002). Conclusion: Serum IGF-2 in combination with IGF-1 and IGFBP-3 can add to the clinical signs of SRS patients and help to perform targeted genetic testing. Further studies are needed.

scholarly journals Genetic characterisation of a cohort of children clinically labelled as GH or IGF1 insensitive: diagnostic value of serum IGF1 and height at presentation

2015 ◽  
Vol 172 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Helen L Storr ◽  
Leo Dunkel ◽  
Julia Kowalczyk ◽  
Martin O Savage ◽  
Louise A Metherell
Keyword(s):  
Elevated Serum ◽  
Growth Failure ◽  
Postnatal Growth ◽  
Diagnostic Value ◽  
Imprinting Control Region ◽  
Postnatal Growth Failure ◽  
Genetics Referral ◽  
Serum Gh ◽  
Silver Russell Syndrome ◽  
Low Serum

Objective and designGH insensitivity (GHI) encompasses growth failure, low serum IGF1 and normal/elevated serum GH. By contrast, IGF1 insensitivity results in pre- and postnatal growth failure associated with relatively high IGF1 levels. From 2008 to 2013, 72 patients from 68 families (45M), mean age 7.1 years (0.4–17.0) with short stature (mean height SDS −3.9; range −9.4 to −1.5), were referred for sequencing.MethodsAs a genetics referral centre, we have sequenced appropriate candidate genes (GHR, including its pseudoexon (6Ψ),STAT5B,IGFALS,IGF1,IGF1R,OBSL1,CUL7andCCDC8) in subjects referred with suspected GHI (n=69) or IGF1 insensitivity (n=3).ResultsMean serum IGF1 SDS was −2.7 (range −0.9 to −8.2) in GHI patients and 2.0, 3.7 and 4.4 in patients with suspected IGF1 insensitivity. Out of 69 GHI patients, 16 (23%) (19% families) had mutations in GH–IGF1 axis genes: homozygousGHR(n=13; 6 6Ψ, two novel IVS5ds+1 G to A) and homozygousIGFALS(n=3; one novel c.1291delT). In the GHI groups, two homozygousOBSL1mutations were also identified (height SDS −4.9 and −5.7) and two patients had hypomethylation in imprinting control region 1 in 11p15 or mUPD7 consistent with Silver–Russell syndrome (SRS) (height SDS −3.7 and −4.3). A novel heterozygousIGF1R(c.112G>A) mutation was identified in one out of three (33%) IGF1-insensitive subjects.ConclusionGenotyping contributed to the diagnosis of children with suspected GHI and IGF1 insensitivity, particularly in the GHI subjects with low serum IGF1 SDS (<−2.0) and height SDS (<−2.5). Diagnoses with similar phenotypes included SRS and 3-M syndrome. In 71% patients, no diagnosis was defined justifying further genetic investigation.

Requirement for mitogen-activated protein kinase activation in the response of embryonic stem cell–derived hematopoietic cells to thrombopoietin in vitro

Blood ◽  
2002 ◽  
Vol 99 (4) ◽  
pp. 1174-1182 ◽  
Author(s):  
Marie-Dominique Filippi ◽  
Françoise Porteu ◽  
Françoise Le Pesteur ◽  
Valérie Schiavon ◽  
Gaël A. Millot ◽  
...  
Keyword(s):  
Growth Factors ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Activation ◽  
Terminal Domain ◽  
Mitogen Activated Protein

Enforced expression of c-mpl in embryonic stem (ES) cells inactivated for this gene results in protein expression in all the ES cell progeny, producing cells that do not belong to the megakaryocytic lineage and are responsive to PEG-rhuMGDF, a truncated form of human thrombopoietin (TPO) conjugated to polyethylene glycol. These include a primitive cell called BL-CFC, thought to represent the equivalent of the hemangioblast, and all myeloid progenitor cells. In this model, PEG-rhuMGDF was able to potentiate the stimulating effects of other growth factors, including vascular endothelial growth factor, on BL-CFC and a combination of cytokines on the growth of granulocyte macrophage–colony-forming units. The importance of the C-terminal domain of Mpl and of mitogen-activated protein kinase (MAPK) activation in TPO-dependent megakaryocytic differentiation has been well studied in vitro. Here, the role of this domain and the involvement of MAPK in upstream and nonmegakaryocytic cells are examined by using 2 truncated mutants of Mpl (Δ34, deletion of residues 71 to 121 in the C-terminal domain; and Δ3, deletion of residues 71-94) and specific inhibitors of the MAPK pathway. The 2 deleted regions support different functions, mediated by different signals. Residues 71 to 121 were required for PEG-rhuMGDF–dependent growth of BL-CFC, for megakaryocytic and other myeloid progenitors, and for megakaryocyte polyploidization. These responses were mediated by the ERK1–ERK2 MAPK pathway. In contrast, the only function of the sequence comprising residues 71 to 94 was to mediate the synergistic effects of PEG-rhuMGDF with other hematopoietic growth factors. This function is not mediated by MAPK activation.

Sign in / Sign up

Export Citation Format

Share Document