| 1. |
- Bademci, Guney, et al.
(författare)
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FOXF2 is required for cochlear development in humans and mice.
- 2019
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Ingår i: Human molecular genetics. - : Oxford University Press (OUP). - 1460-2083 .- 0964-6906. ; 28:8, s. 1286-1297
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Tidskriftsartikel (refereegranskat)abstract
- Molecular mechanisms governing the development of the human cochlea remain largely unknown. Through genome sequencing, we identified a homozygous FOXF2 variant c.325A>T (p.I109F) in a child with profound sensorineural hearing loss associated with incomplete partition type I anomaly of the cochlea. This variant is not found in public databases or in over 1,000 ethnicity-matched control individuals. I109 is a highly conserved residue in the forkhead box (Fox) domain of FOXF2, a member of the Fox protein family of transcription factors that regulate the expression of genes involved in embryogenic development as well as adult life. Our in vitro studies show that the half-life of mutant FOXF2 is reduced compared to that of wildtype. Foxf2 is expressed in the cochlea of developing and adult mice. The mouse knockout of Foxf2 shows shortened and malformed cochleae, in addition to altered shape of hair cells with innervation and planar cell polarity defects. Expressions of Eya1 and Pax3, genes essential for cochlear development, are reduced in the cochleae of Foxf2 knockout mice. We conclude that FOXF2 plays a major role in cochlear development and its dysfunction leads to sensorineural hearing loss and developmental anomalies of the cochlea in humans and mice.
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| 2. |
- Chauhan, Ganesh, et al.
(författare)
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Identification of additional risk loci for stroke and small vessel disease: a meta-analysis of genome-wide association studies
- 2016
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Ingår i: The Lancet Neurology. - 1474-4465 .- 1474-4422. ; 15:7, s. 695-707
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Tidskriftsartikel (refereegranskat)abstract
- Background Genetic determinants of stroke, the leading neurological cause of death and disability, are poorly understood and have seldom been explored in the general population. Our aim was to identify additional loci for stroke by doing a meta-analysis of genome-wide association studies. Methods For the discovery sample, we did a genome-wide analysis of common genetic variants associated with incident stroke risk in 18 population-based cohorts comprising 84 961 participants, of whom 4348 had stroke. Stroke diagnosis was ascertained and validated by the study investigators. Mean age at stroke ranged from 45·8 years to 76·4 years, and data collection in the studies took place between 1948 and 2013. We did validation analyses for variants yielding a significant association (at p<5 × 10−6) with all-stroke, ischaemic stroke, cardioembolic ischaemic stroke, or non-cardioembolic ischaemic stroke in the largest available cross-sectional studies (70 804 participants, of whom 19 816 had stroke). Summary-level results of discovery and follow-up stages were combined using inverse-variance weighted fixed-effects meta-analysis, and in-silico lookups were done in stroke subtypes. For genome-wide significant findings (at p<5 × 10−8), we explored associations with additional cerebrovascular phenotypes and did functional experiments using conditional (inducible) deletion of the probable causal gene in mice. We also studied the expression of orthologs of this probable causal gene and its effects on cerebral vasculature in zebrafish mutants. Findings We replicated seven of eight known loci associated with risk for ischaemic stroke, and identified a novel locus at chromosome 6p25 (rs12204590, near FOXF2) associated with risk of all-stroke (odds ratio [OR] 1·08, 95% CI 1·05–1·12, p=1·48 × 10−8; minor allele frequency 21%). The rs12204590 stroke risk allele was also associated with increased MRI-defined burden of white matter hyperintensity—a marker of cerebral small vessel disease—in stroke-free adults (n=21 079; p=0·0025). Consistently, young patients (aged 2–32 years) with segmental deletions of FOXF2 showed an extensive burden of white matter hyperintensity. Deletion of Foxf2 in adult mice resulted in cerebral infarction, reactive gliosis, and microhaemorrhage. The orthologs of FOXF2 in zebrafish (foxf2b and foxf2a) are expressed in brain pericytes and mutant foxf2b−/− cerebral vessels show decreased smooth muscle cell and pericyte coverage. Interpretation We identified common variants near FOXF2 that are associated with increased stroke susceptibility. Epidemiological and experimental data suggest that FOXF2 mediates this association, potentially via differentiation defects of cerebral vascular mural cells. Further expression studies in appropriate human tissues, and further functional experiments with long follow-up periods are needed to fully understand the underlying mechanisms. Funding NIH, NINDS, NHMRC, CIHR, European national research institutions, Fondation Leducq. © 2016 Elsevier Ltd
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| 3. |
- Cirnaru, Maria-Daniela, et al.
(författare)
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Unbiased identification of novel transcription factors in striatal compartmentation and striosome maturation.
- 2021
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Ingår i: eLife. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Many diseases are linked to dysregulation of the striatum. Striatal function depends on neuronal compartmentation into striosomes and matrix. Striatal projection neurons are GABAergic medium spiny neurons (MSNs), subtyped by selective expression of receptors, neuropeptides, and other gene families. Neurogenesis of the striosome and matrix occurs in separate waves, but the factors regulating compartmentation and neuronal differentiation are largely unidentified. We performed RNA- and ATAC-seq on sorted striosome and matrix cells at postnatal day 3, using the Nr4a1-EGFP striosome reporter mouse. Focusing on the striosome, we validated the localization and/or role of Irx1, Foxf2, Olig2, and Stat1/2 in the developing striosome and the in vivo enhancer function of a striosome-specific open chromatin region 4.4 Kb downstream of Olig2. These data provide novel tools to dissect and manipulate the networks regulating MSN compartmentation and differentiation, including in human iPSC-derived striatal neurons for disease modeling and drug discovery.
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| 4. |
- Moussavi Nik, Seyed Ali
(författare)
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FoxF genes in development and disease
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Forkhead transcription factors of the FoxF group are important during embryonic de-velopment, and mutation of either of the members, Foxf1 and Foxf2, has fatal conse-quences. In this thesis, I present our recent findings about the mechanism of action of FoxF genes in development and disease. Haploinsufficiency for FOXF1 in humans causes alveolar capillary dysplasia with mis-alignment of pulmonary veins (ACDMPV), a rare lethal congenital disorder with incom-plete penetrance. We report a new ACDMPV case and define the genomic rearrangement which consists of a pericentric inversion on chromosome 16 (p11.2q24.1), which dis-rupts the FOXF1 5’-flanking region 134 kb upstream of the first exon. We further use this information in combination with chromatin modification data from the ENCODE data set to predict the extent of the FOXF1 regulatory domain and the critical genomic regions for ACDMPV. Gastrointestinal cancer, which is the result of uncontrolled proliferation of intestinal stem cells, is one of the most prevalent causes of death in the West. We show that Foxf2 regulates the number of intestinal stem cells and the proliferation rate in adult mouse intestine, with consequences for initiation and growth of intestinal tumors. Foxf2 limits the size of the stem cell niche by activating the expression of the extracellular Wnt inhib-itor Sfrp1 in mesenchymal cells surrounding the crypts of Lieberkühn. During this work we also developed a novel method for separation of intact intestinal epithelium from mesenchyme. Cleft palate is a common congenital malformation, associated with many genetic al-terations and environmental teratogens. Loss of Foxf2 results in cleft palate in mouse. We found that the cleft palate is the result of reduced proliferation and decreased extra-cellular matrix production in the neural crest-derived palatal shelf mesenchyme at a critical stage of palatal formation. The mechanistic basis appears to be a diminished Tgfβ signaling, and decreased expression of integrins required for activation of latent Tgfβ.
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| 5. |
- Nik, Ali Moussavi, et al.
(författare)
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Foxf2 in Intestinal Fibroblasts Reduces Numbers of Lgr5(+) Stem Cells and Adenoma Formation by Inhibiting Wnt Signaling
- 2013
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085 .- 1528-0012. ; 144:5, s. 1001-1011
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims The stem cell niche at the base of the intestinal crypts, as well as stemness and high clonogenicity in colon cancer cells, depend on Wnt signaling to β-catenin. Fibroblasts modulate the Wnt pathway in normal and neoplastic epithelial cells via unclear mechanisms. We investigated how in intestinal fibroblasts the forkhead transcription factor Foxf2 controls Wnt signaling to affect numbers of stem cells and formation and growth of adenomas in mice. Methods We created mice with different copy numbers of Foxf2 by generating Foxf2−/+ mice and a transgenic strain, Tg(FOXF2). Adenoma formation was investigated in ApcMin/+ mice, stem cells were counted in mice with the Lgr5–enhanced green fluorescent protein knock-in allele, proliferation was measured by incorporation of bromodeoxyuridine, Foxf2 and Sfrp1 were localized by immunohistochemistry, and signaling pathways were analyzed by quantitative polymerase chain reaction and immunoblot assays. Results Epithelial β-catenin was stabilized in Foxf2−/+ mice, resulting in increased number and size of adenomas. Tg(FOXF2) mice, however, were partially resistant to intestinal neoplasia and developed fewer and smaller adenomas; Foxf2−/+ mice developed 24-fold more tumors than Tg(FOXF2) mice. Epithelial cells of Foxf2−/+ mice also had higher numbers of Lgr5+ stem cells and greater amounts of crypt cell proliferation and expression of Myc (a target of Wnt signaling) than Tg(FOXF2) mice. Expression of Sfrp1, which encodes an extracellular inhibitor of Wnt, in fibroblasts increased with copy number of Foxf2. Conclusions Foxf2 is a fibroblast factor that inhibits paracrine Wnt signaling and restricts the crypt stem cell niche in intestines of mice. Loss of Foxf2 promotes adenoma formation and growth.
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| 6. |
- Nik, Ali Moussavi, et al.
(författare)
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Foxf2 is required for secondary palate development and Tgfβ signaling in palatal shelf mesenchyme.
- 2016
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Ingår i: Developmental Biology. - : Elsevier BV. - 0012-1606 .- 1095-564X. ; 415:1, s. 14-23
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Tidskriftsartikel (refereegranskat)abstract
- The secondary palate separates the oral from the nasal cavity and its closure during embryonic development is sensitive to genetic perturbations. Mice with deleted Foxf2, encoding a forkhead transcription factor, are born with cleft palate, and an abnormal tongue morphology has been proposed as the underlying cause. Here, we show that Foxf2(-/-) maxillary explants cultured in vitro, in the absence of tongue and mandible, failed to close the secondary palate. Proliferation and collagen content were decreased in Foxf2(-/-) palatal shelf mesenchyme. Phosphorylation of Smad2/3 was reduced in mutant palatal shelf, diagnostic of attenuated canonical Tgfβ signaling, whereas phosphorylation of p38 was increased. The amount of Tgfβ2 protein was diminished, whereas the Tgfb2 mRNA level was unaltered. Expression of several genes encoding extracellular proteins important for Tgfβ signaling were reduced in Foxf2(-)(/)(-) palatal shelves: a fibronectin splice-isoform essential for formation of extracellular Tgfβ latency complexes; Tgfbr3 - or betaglycan - which acts as a co-receptor and an extracellular reservoir of Tgfβ; and integrins αV and β1, which are both Tgfβ targets and required for activation of latent Tgfβ. Decreased proliferation and reduced extracellular matrix content are consistent with diminished Tgfβ signaling. We therefore propose that gene expression changes in palatal shelf mesenchyme that lead to reduced Tgfβ signaling contribute to cleft palate in Foxf2(-)(/)(-) mice.
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| 7. |
- Nik, Ali Moussavi, et al.
(författare)
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Separation of intact intestinal epithelium from mesenchyme
- 2013
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Ingår i: Biotechniques. - : Future Science Ltd. - 0736-6205 .- 1940-9818. ; 55:1, s. 42-44
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Tidskriftsartikel (refereegranskat)abstract
- Current protocols for separating adult intestinal epithelial cells from the underlying muscular and mesenchymal tissues typically involve extended incubations, harsh mechanical treatment, and exposure to either proteases or chelating agents. The drawbacks of these approaches include fragmentation, contamination with other cell types, reduced viability, and under-representation of crypt cells. Here we describe a gentle procedure that allows harvesting of pure, fully viable sheets of murine intestinal epithelium, with intact crypts and villi, without enzymes or EDTA. The mesenchyme retains intact villus core projections, is virtually free from epithelial cells, and can be cultured in vitro..
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| 8. |
- Parris, Toshima Z, 1978, et al.
(författare)
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Inversion upstream of FOXF1 in a case of lethal alveolar capillary dysplasia with misalignment of pulmonary veins.
- 2013
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Ingår i: American journal of medical genetics. Part A. - : Wiley. - 1552-4833 .- 1552-4825. ; 161:4, s. 764-70
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Tidskriftsartikel (refereegranskat)abstract
- Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a congenital malformation that leads to severe pulmonary hypertension and respiratory failure. It has been associated with deletion of, or mutation in, FOXF1 on 16q24.1, a gene encoding a forkhead transcription factor expressed in the mesenchyme of the developing lung. Here we report on the identification of a pericentric inversion on chromosome 16 (p11.2q24.1) in a case of lethal ACDMPV with atrioventricular septal defect and duodenal atresia. Array-CGH indicated that the inversion is balanced, and FISH showed that the q-arm breakpoint occurs 134±10kb upstream (5'; centromeric) of FOXF1. This is suggestive of cis-regulatory elements located more than 130kb 5' of FOXF1, and analysis of genome-wide data sets of chromatin modifications in two different cell types suggested that the FOXF1 regulatory domain covers more than 300kb, and perhaps up to 433kb, upstream of the gene, but only 3kb downstream. The 588kb gene-free region between FOXF1 and the next gene in the centromeric direction, IRF8, is highly conserved between species and divided into two distinct regulatory domains by an insulator element. Another putative insulator occurs just downstream of FOXF1. Our results further strengthen the association between FOXF1 and a spectrum of malformations that include ACDMPV, atrioventricular septal defects, and gastrointestinal atresia. Furthermore, the presented analysis aids in defining the critical genomic region for this syndrome. © 2013 Wiley Periodicals, Inc.
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| 9. |
- Perman Sundelin, Jeanna, et al.
(författare)
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Hypoxia-induced regulation of the very low density lipoprotein receptor
- 2013
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 437:2, s. 274-279
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Tidskriftsartikel (refereegranskat)abstract
- The very low density lipoprotein receptor (VLDLr) is highly upregulated during hypoxia in mouse cardiomyocytes and in human and mouse ischemic hearts causing a detrimental lipid accumulation. To know how the gene is regulated is important for future studies. In this study, we have thoroughly mapped the 5 '-flanking region of the mouse VLDLr promoter and show that the hypoxia-mediated increase in VLDLr expression is dependent on Hif-1 alpha, binding to a hypoxia responsive element (HRE) located at -162 to-158 bp 5 ' of translation start. We show that classical HRE sites and the previously described PPAR gamma and Sp1 binding are not involved in the hypoxia-induced regulation of the VLDLr promoter. Using a chromatin immunoprecipitation (ChIP) assay, we show that Hif-1 alpha t specifically binds and activates the mouse VLDLr promoter at the previously described non-classical HRE in HL-1 cells. We also show that the same HRE is present and active in response to hypoxia in human cardiomyocytes, however at a different location (-812 bp from translation start). These results conclude that in the hypoxic hearts of mice and men, the VLDLr gene is regulated by a direct binding of Hif-1 alpha to the VLDLr promoter. (C) 2013 Elsevier Inc. All rights reserved.
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| 10. |
- Reyahi, Azadeh, et al.
(författare)
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Foxf2 Is Required for Brain Pericyte Differentiation and Development and Maintenance of the Blood-Brain Barrier
- 2015
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Ingår i: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 34:1, s. 19-32
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Tidskriftsartikel (refereegranskat)abstract
- Pericytes are critical for cerebrovascular maturation and development of the blood-brain barrier (BBB), but their role in maintenance of the adult BBB, and how CNS pericytes differ from those of other tissues, is less well understood. We show that the forkhead transcription factor Foxf2 is specifically expressed in pericytes of the brain and that Foxf2(-/-) embryos develop intracranial hemorrhage, perivascular edema, thinning of the vascular basal lamina, an increase of luminal endothelial caveolae, and a leaky BBB. Foxf2(-/-) brain pericytes were more numerous, proliferated faster, and expressed significantly less Pdgfr beta. Tgf beta-Smad2/3 signaling was attenuated, whereas phosphorylation of Smad1/5 and p38 were enhanced. Tgf beta pathway components, including Tgf beta 2, Tgf beta r2, Alk5, and integrins alpha(V)beta(8), were reduced. Foxf2 inactivation in adults resulted in BBB breakdown, endothelial thickening, and increased trans-endothelial vesicular transport. On the basis of these results, FOXF2 emerges as an interesting candidate locus for stroke susceptibility in humans.
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