scholarly journals Elevated inflammatory gene expression in intervertebral disc tissues in mice with ADAM8 inactivated

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yejia Zhang ◽  
Zuozhen Tian ◽  
David Gerard ◽  
Lutian Yao ◽  
Frances S. Shofer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Intervertebral Disc ◽  
Inflammatory Markers ◽  
Polarized Light ◽  
Mutant Mice ◽  
Wild Type ◽  
Fiber Assembly ◽  
Complete Inactivation ◽  
Elevated Expression ◽  
Inflammatory Processes

AbstractWe found ADAM8 enzymatic activity elevated in degenerative human intervertebral disc (IVD). Here, we examined the discs in ADAM8-inactivation mice that carry a mutation preventing self-activation of the enzyme. Surprisingly, elevated gene expression for inflammatory markers (Cxcl1, IL6) was observed in injured discs of ADAM8 mutant mice, along with elevated expression of type 2 collagen gene (Col2a1), compared with wild type controls. Injured annulus fibrosus of mutant and wild type mice contained a higher proportion of large collagen fibers compared with intact discs, as documented by microscopic examination under circular polarized light. In the intact IVDs, Adam8EQ mouse AF contained lower proportion of yellow (intermediate) fiber than WT mice. This suggests that ADAM8 may regulate inflammation and collagen fiber assembly. The seemingly contradictory findings of elevated inflammatory markers in mutant mice and excessive ADAM8 activity in human degenerative discs suggest that ADAM8 may interact with other enzymatic and pro-inflammatory processes needed for tissue maintenance and repair. As a future therapeutic intervention to retard intervertebral disc degeneration, partial inhibition of ADAM8 proteolysis may be more desirable than complete inactivation of this enzyme.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals Neurons Expressing the Highest Levels of γ-Synuclein Are Unaffected by Targeted Inactivation of the Gene

2003 ◽  
Vol 23 (22) ◽  
pp. 8233-8245 ◽  
Author(s):  
Natalia Ninkina ◽  
Katerina Papachroni ◽  
Darren C. Robertson ◽  
Oliver Schmidt ◽  
Liz Delaney ◽  
...  
Keyword(s):  
Es Cells ◽  
Culture Conditions ◽  
Sensory Function ◽  
Mutant Mice ◽  
Null Mutant ◽  
Wild Type ◽  
Complete Inactivation ◽  
Null Mutant Mice

ABSTRACT Homologous recombination in ES cells was employed to generate mice with targeted deletion of the first three exons of the γ-synuclein gene. Complete inactivation of gene expression in null mutant mice was confirmed on the mRNA and protein levels. Null mutant mice are viable, are fertile, and do not display evident phenotypical abnormalities. The effects of γ-synuclein deficiency on motor and peripheral sensory neurons were studied by various methods in vivo and in vitro. These two types of neurons were selected because they both express high levels of γ-synuclein from the early stages of mouse embryonic development but later in the development they display different patterns of intracellular compartmentalization of the protein. We found no difference in the number of neurons between wild-type and null mutant animals in several brain stem motor nuclei, in lumbar dorsal root ganglia, and in the trigeminal ganglion. The survival of γ-synuclein-deficient trigeminal neurons in various culture conditions was not different from that of wild-type neurons. There was no difference in the numbers of myelinated and nonmyelinated fibers in the saphenous nerves of these animals, and sensory reflex thresholds were also intact in γ-synuclein null mutant mice. Nerve injury led to similar changes in sensory function in wild-type and mutant mice. Taken together, our data suggest that like α-synuclein, γ-synuclein is dispensable for the development and function of the nervous system.

Clockmutation facilitates accumulation of cholesterol in the liver of mice fed a cholesterol and/or cholic acid diet

2008 ◽  
Vol 294 (1) ◽  
pp. E120-E130 ◽  
Author(s):  
Takashi Kudo ◽  
Mihoko Kawashima ◽  
Toru Tamagawa ◽  
Shigenobu Shibata
Keyword(s):  
Gene Expression ◽  
Circadian Clock ◽  
Cholic Acid ◽  
Mouse Liver ◽  
Clock Genes ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Mutant Mice ◽  
Wild Type ◽  
Clock Mutant

Cholesterol (CH) homeostasis in the liver is regulated by enzymes of CH synthesis such as 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and catabolic enzymes such as cytochrome P-450, family 7, subfamily A, and polypeptide 1 (CYP7A1). Since a circadian clock controls the gene expression of these enzymes, these genes exhibit circadian rhythm in the liver. In this study, we examined the relationship between a diet containing CH and/or cholic acid (CA) and the circadian regulation of Hmgcr, low-density lipoprotein receptor ( Ldlr), and Cyp7a1 gene expression in the mouse liver. A 4-wk CA diet lowered and eventually abolished the circadian expression of these genes. Not only clock genes such as period homolog 2 (Drosophila) ( Per2) and brain and muscle arnt-like protein-1 ( Bmal1) but also clock-controlled genes such as Hmgcr, Ldlr, and Cyp7a1 showed a reduced and arrhythmic expression pattern in the liver of Clock mutant mice. The reduced gene expression of Cyp7a1 in mice fed a diet containing CA or CH + CA was remarkable in the liver of Clock mutants compared with wild-type mice, and high liver CH accumulation was apparent in Clock mutant mice. In contrast, a CH diet without CA only elevated Cyp7a1 expression in both wild-type and Clock mutant mice. The present findings indicate that normal circadian clock function is important for the regulation of CH homeostasis in the mouse liver, especially in conjunction with a diet containing high CH and CA.

Iron absorption and hepatic iron uptake are increased in a transferrin receptor 2 (Y245X) mutant mouse model of hemochromatosis type 3

2007 ◽  
Vol 292 (1) ◽  
pp. G323-G328 ◽  
Author(s):  
S. F. Drake ◽  
E. H. Morgan ◽  
C. E. Herbison ◽  
R. Delima ◽  
R. M. Graham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mouse Model ◽  
Transferrin Receptor ◽  
Mutant Mouse ◽  
Hereditary Hemochromatosis ◽  
Mutant Mice ◽  
Wild Type ◽  
Hepcidin Expression ◽  
Fe Uptake ◽  
Type 3

Hereditary hemochromatosis type 3 is an iron (Fe)-overload disorder caused by mutations in transferrin receptor 2 (TfR2). TfR2 is expressed highly in the liver and regulates Fe metabolism. The aim of this study was to investigate duodenal Fe absorption and hepatic Fe uptake in a TfR2 (Y245X) mutant mouse model of hereditary hemochromatosis type 3. Duodenal Fe absorption and hepatic Fe uptake were measured in vivo by 59Fe-labeled ascorbate in TfR2 mutant mice, wild-type mice, and Fe-loaded wild-type mice (2% dietary carbonyl Fe). Gene expression was measured by real-time RT-PCR. Liver nonheme Fe concentration increased progressively with age in TfR2 mutant mice compared with wild-type mice. Fe absorption (both duodenal Fe uptake and transfer) was increased in TfR2 mutant mice compared with wild-type mice. Likewise, expression of genes participating in duodenal Fe uptake ( Dcytb, DMT1) and transfer (ferroportin) were increased in TfR2 mutant mice. Nearly all of the absorbed Fe was taken up rapidly by the liver. Despite hepatic Fe loading, hepcidin expression was decreased in TfR2 mutant mice compared with wild-type mice. Even when compared with Fe-loaded wild-type mice, TfR2 mutant mice had increased Fe absorption, increased duodenal Fe transport gene expression, increased liver Fe uptake, and decreased liver hepcidin expression. In conclusion, despite systemic Fe loading, Fe absorption and liver Fe uptake were increased in TfR2 mutant mice in association with decreased expression of hepcidin. These findings support a model in which TfR2 is a sensor of Fe status and regulates duodenal Fe absorption and liver Fe uptake.

scholarly journals Chd8 haploinsufficiency impairs early brain development and protein homeostasis later in life

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jessica A. Jiménez ◽  
Travis S. Ptacek ◽  
Alex H. Tuttle ◽  
Ralf S. Schmid ◽  
Sheryl S. Moy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cerebral Cortex ◽  
Er Stress ◽  
Stop Codon ◽  
Autism Spectrum ◽  
Mutant Mice ◽  
Wild Type ◽  
Age Related ◽  
Transcriptional Changes ◽  
Regulated Gene Expression

Abstract Background Chromodomain helicase DNA-binding protein 8 (Chd8) is a high-confidence risk gene for autism spectrum disorder (ASD). However, how Chd8 haploinsufficiency impairs gene expression in the brain and impacts behavior at different stages of life is unknown. Methods We generated a mutant mouse line with an ASD-linked loss-of-function mutation in Chd8 (V986*; stop codon mutation). We examined the behavior of Chd8 mutant mice along with transcriptional changes in the cerebral cortex as a function of age, with a focus on one embryonic (E14.5) and three postnatal ages (1, 6, and 12 months). Results Chd8V986*/+ mutant mice displayed macrocephaly, reduced rearing responses and reduced center time in the open field, and enhanced social novelty preference. Behavioral phenotypes were more evident in Chd8V986*/+ mutant mice at 1 year of age. Pup survival was reduced in wild-type x Chd8V986*/+ crosses when the mutant parent was female. Transcriptomic analyses indicated that pathways associated with synaptic and neuronal projections and sodium channel activity were reduced in the cortex of embryonic Chd8V986*/+ mice and then equalized relative to wild-type mice in the postnatal period. At 12 months of age, expression of genes associated with endoplasmic reticulum (ER) stress, chaperone-mediated protein folding, and the unfolded protein response (UPR) were reduced in Chd8V986*/+ mice, whereas genes associated with the c-MET signaling pathway were increased in expression. Limitations It is unclear whether the transcriptional changes observed with age in Chd8V986*/+ mice reflect a direct effect of CHD8-regulated gene expression, or if CHD8 indirectly affects the expression of UPR/ER stress genes in adult mice as a consequence of neurodevelopmental abnormalities. Conclusions Collectively, these data suggest that UPR/ER stress pathways are reduced in the cerebral cortex of aged Chd8V986*/+ mice. Our study uncovers neurodevelopmental and age-related phenotypes in Chd8V986*/+ mice and highlights the importance of controlling for age when studying Chd8 haploinsufficient mice.

Abstract 632: Aortic Dilatation in Marfan Syndrome: A Result of Amplification of Molecular Mechanisms of Aging?

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Michael A Hagler ◽  
Grace Casaclang-Verzosa ◽  
Bin Zhang ◽  
Carolyn Roos ◽  
Nassir Thalji ◽  
...  
Keyword(s):  
Gene Expression ◽  
Marfan Syndrome ◽  
Aortic Root ◽  
Expression Patterns ◽  
Mutant Mice ◽  
Aortic Dilatation ◽  
Mrna Levels ◽  
Wild Type ◽  
Fibrillin 1 ◽  
Tgf Β1

Marfan syndrome (MFS) is a genetic disease with a mutation for the microfibrillar constituent protein fibrillin-1 being the most prevalent. MFS is often associated with progressive aortic root dilation, ultimately progressing to aortic aneurysm and dissection. While recent work has shown that increased angiotensin-II receptor type-1 and transforming growth factor beta (TGF-β) signaling contributes to aneurysm formation in aorta, efficacious therapeutic targets remain elusive. Given previous reports of progeriod phenotypes in a subset of Marfan patients, we sought to determine whether there are molecular changes that are consistent with accelerated aging in a mouse model of Marfan syndrome. In mice carrying a loss-of-function mutation in fibrillin-1, we assessed aortic root dimensions by echocardiography and gene expression levels of TGF-β1-3, runt related transcription factor 2 (RUNX2), and the cellular senescent marker CDKN2A by quantitative real time PCR at 3 and 14 months of age. As expected, aortic sinus dimensions did not change significantly with aging in wild type mice, but increased dramatically in fibrillin-1 mutant mice compared to wild-type littermate controls and with age (p < 0.05 for both). TGF-β1 ligand expression paralleled age and disease-dependent changes in aortic dimensions, however TGF-β2 and TGF-β3 mRNA levels did not. Aortic dilatation was associated with increased gene expression of RUNX2 with aging and in marfanoid mice. Interestingly, fibrillin-1 mutant mice demonstrated marked increases in expression of the anti-proliferative cell-cycle checkpoint protein CDKN2A at both time points, and correlated with changes in TGF-β1 (R 2 =0.54) and RUNX2 (R 2 =0.69) mRNA. CDNK2A gene expression patterns, however, demonstrated a poor correlation with expression of TGF-β2 and TGF-β3 (R 2 =0.04 and 0.06. respectively). Collectively, these data lend insight into novel mechanisms that may regulate development of aortic root dilation in patients MFS and are the first to implicate increased senescent cell burden in Marfan syndrome. Furthermore, we propose that clearance of senescent cells could be a viable therapeutic intervention to slow progression aortic root-dilation and aneurysm in patients with Marfan syndrome.

scholarly journals Spontaneous Facet Joint Osteoarthritis in NFAT1-Mutant Mice

2021 ◽  
Author(s):  
Jinxi Wang ◽  
Qinghua Lu ◽  
Matthew J. Mackay ◽  
Xiangliang Liu ◽  
Yi Feng ◽  
...  
Keyword(s):  
Gene Expression ◽  
Scoring System ◽  
Structural Changes ◽  
Facet Joint ◽  
Mutant Mice ◽  
Facet Joints ◽  
Wild Type ◽  
Tissue Specific ◽  
Facet Joint Osteoarthritis ◽  
Gene And Protein Expression

ABSTRACTObjectivesAlthough rodent models of traumatically or chemically induced intervertebral facet joint osteoarthritis (FJOA) were previously described, the characteristics of spontaneous FJOA animal models have not been documented. This study aimed to identify the characteristics of a murine model of spontaneous FJOA and its underlying mechanisms.MethodsThe lumbar facet joints of mutant mice carrying a disrupted NFAT1 (nuclear factor of activated T cells 1) allele and of wild-type control mice were examined by histochemistry, quantitative gene expression analysis, immunohistochemistry, and histomorphometry using a novel FJOA scoring system at 2, 6, 12, and 18 months of age. The reproducibility of the FJOA scoring system was analyzed by inter-observer and intra-observer variability tests. Tissue-specific histomorphometric and gene expression changes were statistically analyzed.ResultsNFAT1-mutant facet joints displayed dysfunction of articular chondrocytes and synovial cells with aberrant gene and protein expression in cartilage and synovium as early as 2 months, followed by osteoarthritic structural changes such as articular surface fissuring and chondro-osteophyte formation at 6 months. Deeper cartilage lesions, synovitis, separation of cartilage from thickened subchondral bone, and tissue-specific molecular and cellular alterations in NFAT1-mutant facet joints became evident at 12 and 18 months. Osteoarthritic structural changes were not detected in wild-type facet joints at any ages, though age-related cartilage degeneration was observed at 18 months.ConclusionsUsing NFAT1-mutant mice, this study has identified for the first time an animal model of spontaneous FJOA with age-dependent osteoarthritic characteristics, developed the first FJOA scoring system, and elucidated the molecular mechanisms of NFAT1 mutation-mediated FJOA.

DNA Demethylation Regulates Anabolic and Catabolic Gene Expression in Intervertebral Disc Cells

2014 ◽  
Vol 4 (1_suppl) ◽  
pp. s-0034-1376587-s-0034-1376587
Author(s):  
N. Chutkan ◽  
R. Sangani ◽  
H. Zhou ◽  
S. Fulzele
Keyword(s):  
Gene Expression ◽  
Intervertebral Disc ◽  
Dna Demethylation ◽  
Catabolic Gene ◽  
Disc Cells

scholarly journals Gene expression-based biomarkers designating glioblastomas resistant to multiple treatment strategies

2021 ◽  
Author(s):  
Otília Menyhárt ◽  
János Tibor Fekete ◽  
Balázs Győrffy
Keyword(s):  
Gene Expression ◽  
Treatment Strategies ◽  
Area Under The Curve ◽  
Predictive Biomarkers ◽  
Subsequent Treatment ◽  
Survival Status ◽  
Multiple Treatment ◽  
Post Surgery ◽  
Potential Biomarker ◽  
Elevated Expression

Abstract Despite advances in molecular characterization of glioblastoma multiforme (GBM), only a handful of predictive biomarkers exist with limited clinical relevance. We aimed to identify differentially expressed genes in tumor samples collected at surgery associated with response to subsequent treatment, including temozolomide (TMZ) and nitrosoureas. Gene expression was collected from multiple independent datasets. Patients were categorized as responders/nonresponders based on their survival status at 16 months post-surgery. For each gene, the expression was compared between responders and nonresponders with a Mann-Whitney U test and receiver operating characteristic. The package "roc" was used to calculate the area under the curve (AUC). The integrated database comprises 454 GBM patients from three independent datasets and 10,103 genes. The highest proportion of responders (68%) were among patients treated with TMZ combined with nitrosoureas, where FCGR2B upregulation provided the strongest predictive value (AUC=0.72, p &lt; 0.001). Elevated expression of CSTA and MRPS17 was associated with a lack of response to multiple treatment strategies. DLL3 upregulation was present in subsequent responders to any treatment combination containing TMZ. Three genes (PLSCR1, MX1, and MDM2) upregulated both in the younger cohort and in patients expressing low MGMT delineate a subset of patients with worse prognosis within a population generally associated with a favorable outcome. The identified transcriptomic changes provide biomarkers of responsiveness, offer avenues for preclinical studies, and may enhance future GBM patient stratifications. The described methodology provides a reliable pipeline for the initial testing of potential biomarker candidates for future validation studies.

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