| 1. |
- Brun, Ann, et al.
(författare)
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Hoxb4-deficient mice undergo normal hematopoietic development but exhibit a mild proliferation defect in hematopoietic stem cells
- 2004
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 103:11, s. 4126-4133
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Tidskriftsartikel (refereegranskat)abstract
- Enforced expression of Hoxb4 dramatically increases the regeneration of murine hematopoietic stem cells (HSCs) after transplantation and enhances the repopulation ability of human severe combined immunodeficiency (SCID) repopulating cells. Therefore, we asked what physiologic role Hoxb4 has in hematopoiesis. A novel mouse model lacking the entire Hoxb4 gene exhibits significantly reduced cellularity in spleen and bone marrow (BM) and a subtle reduction in red blood cell counts and hemoglobin values. A mild reduction was observed in the numbers of primitive progenitors and stem cells in adult BM and fetal liver, whereas lineage distribution was normal. Although the cell cycle kinetics of primitive progenitors was normal during endogenous hematopoiesis, defects in proliferative responses of BM Lin(-) Sca1(+) c-kit(+) stem and progenitor cells were observed in culture and in vivo after the transplantation of BM and fetal liver HSCs. Quantitative analysis of mRNA from fetal liver revealed that a deficiency of Hoxb4 alone changed the expression levels of several other Hox genes and of genes involved in cell cycle regulation. In summary, the deficiency of Hoxb4 leads to hypocellularity in hematopoietic organs and impaired proliferative capacity. However, Hoxb4 is not required for the generation of HSCs or the maintenance of steady state hematopoiesis.
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| 2. |
- Davoudi, Mina, et al.
(författare)
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A mouse model of mitochondrial complex III dysfunction induced by myxothiazol.
- 2014
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 446:4, s. 1079-1084
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Tidskriftsartikel (refereegranskat)abstract
- Myxothiazol is a respiratory chain complex III (CIII) inhibitor that binds to the ubiquinol oxidation site Qo of CIII. It blocks electron transfer from ubiquinol to cytochrome b and thus inhibits CIII activity. It has been utilized as a tool in studies of respiratory chain function in in vitro and cell culture models. We developed a mouse model of biochemically induced and reversible CIII inhibition using myxothiazol. We administered myxothiazol intraperitoneally at a dose of 0.56mg/kg to C57Bl/J6 mice every 24h and assessed CIII activity, histology, lipid content, supercomplex formation, and gene expression in the livers of the mice. A reversible CIII activity decrease to 50% of control value occurred at 2h post-injection. At 74h only minor histological changes in the liver were found, supercomplex formation was preserved and no significant changes in the expression of genes indicating hepatotoxicity or inflammation were found. Thus, myxothiazol-induced CIII inhibition can be induced in mice for four days in a row without overt hepatotoxicity or lethality. This model could be utilized in further studies of respiratory chain function and pharmacological approaches to mitochondrial hepatopathies.
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| 3. |
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| 4. |
- Falk, Sven, et al.
(författare)
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Brain area-specific effect of TGF-beta signaling on Wnt-dependent neural stem cell expansion
- 2008
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 2:5, s. 472-483
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Tidskriftsartikel (refereegranskat)abstract
- Regulating the choice between neural stem cell maintenance versus differentiation determines growth and size of the developing brain. Here we identify TGF-beta signaling as a crucial factor controlling these processes. At early developmental stages, TGF-beta signal activity is localized close to the ventricular surface of the neuroepithelium. In the midbrain, but not in the forebrain, Tgfbr2 ablation results in ectopic expression of Wnt1/beta-catenin and FGF8, activation of Wnt target genes, and increased proliferation and horizontal expansion of neuroepithelial cells due to shortened cell-cycle length and decreased cell-cycle exit. Consistent with this phenotype, self-renewal of mutant neuroepithelial stem cells is enhanced in the presence of FGF and requires Wnt signaling. Moreover, TGF-beta signal activation counteracts Wnt-incluced proliferation of midbrain neuroepithelial cells. Thus, TGF-beta signaling controls the size of a specific brain area, the dorsal midbrain, by antagonizing canonical Wnt signaling and negatively regulating self-renewal of neuroepithelial stem cells.
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| 5. |
- Frutkin, Andrew D., et al.
(författare)
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A critical developmental role for tgfbr2 in myogenic cell lineages is revealed in mice expressing SM22-Cre, not SMMHC-Cre
- 2006
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Ingår i: Journal of Molecular and Cellular Cardiology. - : Elsevier BV. - 1095-8584 .- 0022-2828. ; 41:4, s. 724-731
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Tidskriftsartikel (refereegranskat)abstract
- Smooth muscle cell (SMC)-specific deletion of transforming growth factor beta (TGF-beta) signaling would help elucidate the mechanisms through which TGF-beta signaling contributes to vascular development and disease. We attempted to generate mice with SMC-specific deletion of TGF-beta signaling by mating mice with a conditional ("floxed") allele for the type 11 TGF-beta receptor (tgfbr2(flox)) to mice with SMC-targeted expression of Cre recombinase. We bred male mice transgenic for smooth muscle myosin heavy chain (SMMHC)-Cre with females carrying tgfbr2(flox). Surprisingly, SMMHC-Cre rnice recombined tglbr2(flox) at low levels in SMC and at high levels in the testis. Recombination of tgfbr2(flox) in testis correlated with high-level expression of SMMHC-Cre in testis and germline transmission of tgfbr2(null). In contrast, mice expressing Cre from a SM22 alpha promoter (SM22-Cre) efficiently recombined tgfbr2(flox) in vascular and visceral SMC and the heart, but not in testis. Use of the R26R reporter allele confirmed that Cre-mediated recombination in vascular SMC was inefficient for SMMHC-Cre mice and highly efficient for SM22-Cre mice. Breedings that introduced the SM22-Cre allele into tgfbr2(flox) zygotes in order to generate adult mice that are hemizygous for SM22-Cre and homozygous for tgfbr2(flox) and would have conversion of tgfbr2(flox/flox) to tgfbr2(null/null) in SMC-produced no live SM22-Cre : tgfbr2(flox/flox) pups (P < 0.001). We conclude: (1) "SMC-targeted" Cre lines vary significantly in specificity and efficiency of Cre expression; (2) TGF-beta signaling in the subset of cells that express SM22 alpha is required for normal development; (3) generation of adult mice with absent TGF-beta signaling in SMC remains a challenge. (c) 2006 Elsevier Inc. All rights reserved.
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| 6. |
- Ittner, Lars M, et al.
(författare)
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Compound developmental eye disorders following inactivation of TGFbeta signaling in neural-crest stem cells
- 2005
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Ingår i: Journal of Biology. - : Springer Science and Business Media LLC. - 1475-4924. ; 4:11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Development of the eye depends partly on the periocular mesenchyme derived from the neural crest (NC), but the fate of NC cells in mammalian eye development and the signals coordinating the formation of ocular structures are poorly understood. RESULTS: Here we reveal distinct NC contributions to both anterior and posterior mesenchymal eye structures and show that TGFbeta signaling in these cells is crucial for normal eye development. In the anterior eye, TGFbeta2 released from the lens is required for the expression of transcription factors Pitx2 and Foxc1 in the NC-derived cornea and in the chamber-angle structures of the eye that control intraocular pressure. TGFbeta enhances Foxc1 and induces Pitx2 expression in cell cultures. As in patients carrying mutations in PITX2 and FOXC1, TGFbeta signal inactivation in NC cells leads to ocular defects characteristic of the human disorder Axenfeld-Rieger's anomaly. In the posterior eye, NC cell-specific inactivation of TGFbeta signaling results in a condition reminiscent of the human disorder persistent hyperplastic primary vitreous. As a secondary effect, retinal patterning is also disturbed in mutant mice. CONCLUSION: In the developing eye the lens acts as a TGFbeta signaling center that controls the development of eye structures derived from the NC. Defective TGFbeta signal transduction interferes with NC-cell differentiation and survival anterior to the lens and with normal tissue morphogenesis and patterning posterior to the lens. The similarity to developmental eye disorders in humans suggests that defective TGFbeta signal modulation in ocular NC derivatives contributes to the pathophysiology of these diseases.
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| 7. |
- Kalis, Martins, et al.
(författare)
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Variants in the FFAR1 Gene Are Associated with Beta Cell Function
- 2007
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 2:11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The FFAR1 receptor is expressed mainly in pancreatic beta cells and is activated by medium to long chain free fatty acids (FFAs), as well as by thiazolidinediones, resulting in elevated Ca(2+) concentrations and promotion of insulin secretion. These properties suggest that FFAR1 could be a mediator of lipotoxicity and a potential candidate gene for Type 2 diabetes (T2D). We therefore investigated whether variations at the FFAR1 locus are associated with T2D and beta cell function. METHODOLOGY/PRINCIPAL FINDINGS: We re-sequenced the FFAR1 region in 96 subjects (48 healthy and 48 T2D individuals) and found 13 single nucleotide polymorphisms (SNPs) 8 of which were not previously described. Two SNPs located in the upstream region of the FFAR1 gene (rs1978013 and rs1978014) were chosen and genotyped in 1929 patients with T2D and 1405 healthy control subjects. We observed an association of rs1978013 and rs1978014 with insulinogenic index in males (p = 0.024) and females (p = 0.032), respectively. After Bonferroni corrections, no association with T2D was found in the case-control material, however a haplotype consisting of the T-G alleles conferred protection against T2D (p = 0.0010). CONCLUSIONS/SIGNIFICANCE: Variation in the FFAR1 gene may contribute to impaired beta cell function in T2D.
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| 8. |
- Koskela, Anita, 1979-, et al.
(författare)
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Evaluation of Microsatellite instability score from GMS560 DNA panel
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Microsatellite instability is characterised by gains or losses of nucleotides in short tandem repeat sequences, microsatellites, dispersed throughout the human genome. Microsatellite instability status is a molecular fingerprint for DNA mismatch repair deficiency. Clinical detection of microsatellite instability status is important for identifying inherited disease in patients with colorectal and endometrial cancer but has also a prognostic value for survival and prediction of treatment response. Lately, microsatellite instability has been used as a tumor agnostic biomarker that predicts response to immune checkpoint inhibitors. To identify microsatellite instability status clinically, PCR and immunohistochemistry have been the gold standard. On the contrary, next generation sequencing provide simultaneous accession of large number of microsatellite loci and can be combined with detection of several other biomarkers. The national collaboration Genome Medicine Sweden have developed a solid tumour gene panel composed of 560 cancer associated genes with integrated microsatellite instability score. Our aim was to validate the microsatellite instability status based on microsatellite instability score from GMS560 DNA panel against the clinically used methods. Extracted DNA (100 ng) from formalin fixed paraffin embedded tissue sections with various tumour cell content >10% were analysed. During target enrichment sequencing analysis, allelic distribution from 5000 microsatellite markers were calculated by MSIsensor Pro to generate an instability score. The cohort consisted of microsatellite instable verified colorectal cancer samples (n=20), microsatellite stable solid tumour material (n=60). Preliminary results generated a microsatellite instability score for the colorectal cancer samples with a mean of 26.5 % (CI: 23.4-29.6, range: 16.9-32.3). Microsatellite stable tumour samples had a mean microsatellite instability score of 1.5 % (CI: 0.93-2.07, range: 1-4.45). In conclusion, we found the microsatellite instability score from GMS560 DNA panel to be both diagnostically sensitive and specific for determining MSI status due to obvious separation in instability.
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| 9. |
- Kotarsky, Heike, et al.
(författare)
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Metabolite Profiles Reveal Energy Failure and Impaired Beta-Oxidation in Liver of Mice with Complex III Deficiency Due to a BCS1L Mutation.
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Liver is a target organ in many mitochondrial disorders, especially if the complex III assembly factor BCS1L is mutated. To reveal disease mechanism due to such mutations, we have produced a transgenic mouse model with c.232A>G mutation in Bcs1l, the causative mutation for GRACILE syndrome. The homozygous mice develop mitochondrial hepatopathy with steatosis and fibrosis after weaning. Our aim was to assess cellular mechanisms for disease onset and progression using metabolomics. METHODS: With mass spectrometry we analyzed metabolite patterns in liver samples obtained from homozygotes and littermate controls of three ages. As oxidative stress might be a mechanism for mitochondrial hepatopathy, we also assessed H(2)O(2) production and expression of antioxidants. RESULTS: Homozygotes had a similar metabolic profile at 14 days of age as controls, with the exception of slightly decreased AMP. At 24 days, when hepatocytes display first histopathological signs, increases in succinate, fumarate and AMP were found associated with impaired glucose turnover and beta-oxidation. At end stage disease after 30 days, these changes were pronounced with decreased carbohydrates, high levels of acylcarnitines and amino acids, and elevated biogenic amines, especially putrescine. Signs of oxidative stress were present in end-stage disease. CONCLUSIONS: The findings suggest an early Krebs cycle defect with increases of its intermediates, which might play a role in disease onset. During disease progression, carbohydrate and fatty acid metabolism deteriorate leading to a starvation-like condition. The mouse model is valuable for further investigations on mechanisms in mitochondrial hepatopathy and for interventions.
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| 10. |
- Larsson, Anna H, et al.
(författare)
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Validation of podocalyxin-like protein as a biomarker of poor prognosis in colorectal cancer
- 2012
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 12, s. 282-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Podocalyxin-like 1 (PODXL) is a cell-adhesion glycoprotein and stem cell marker that has been associated with an aggressive tumour phenotype and adverse outcome in several cancer types. We recently demonstrated that overexpression of PODXL is an independent factor of poor prognosis in colorectal cancer (CRC). The aim of this study was to validate these results in two additional independent patient cohorts and to examine the correlation between PODXL mRNA and protein levels in a subset of tumours. Method: PODXL protein expression was analyzed by immunohistochemistry in tissue microarrays with tumour samples from a consecutive, retrospective cohort of 270 CRC patients (cohort 1) and a prospective cohort of 337 CRC patients (cohort 2). The expression of PODXL mRNA was measured by real-time quantitative PCR in a subgroup of 62 patients from cohort 2. Spearman's Rho and Chi-Square tests were used for analysis of correlations between PODXL expression and clinicopathological parameters. Kaplan Meier analysis and Cox proportional hazards modelling were applied to assess the relationship between PODXL expression and time to recurrence (TTR), disease free survival (DFS) and overall survival (OS). Results: High PODXL protein expression was significantly associated with unfavourable clinicopathological characteristics in both cohorts. In cohort 1, high PODXL expression was associated with a significantly shorter 5-year OS in both univariable (HR = 2.28; 95% CI 1.43-3.63, p = 0.001) and multivariable analysis (HR = 2.07; 95% CI 1.25-3.43, p = 0.005). In cohort 2, high PODXL expression was associated with a shorter TTR (HR = 2.93; 95% CI 1.26-6.82, p = 0.013) and DFS (HR = 2.44; 95% CI 1.32-4.54, p = 0.005), remaining significant in multivariable analysis, HR = 2.50; 95% CI 1.05-5.96, p = 0.038 for TTR and HR = 2.11; 95% CI 1.13-3.94, p = 0.019 for DFS. No significant correlation could be found between mRNA levels and protein expression of PODXL and there was no association between mRNA levels and clinicopathological parameters or survival. Conclusions: Here, we have validated the previously demonstrated association between immunohistochemical expression of PODXL and poor prognosis in CRC in two additional independent patient cohorts. The results further underline the potential utility of PODXL as a biomarker for more precise prognostication and treatment stratification of CRC patients.
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