| 1. |
- Agudo, Marta, et al.
(författare)
-
Immediate Upregulation of Proteins Belonging to Different Branches of the Apoptotic Cascade in the Retina after Optic Nerve Transection and Optic Nerve Crush
- 2009
-
Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 50:1, s. 424-431
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To further investigate the molecular signals underlying optic nerve (ON) injury we have analyzed in adult control, ON transected and ON crushed retinas, the expression pattern and time-course regulation of the following proteins, all of which are linked to apoptosis through different pathways: Stat 1, Caspase 11 (inflammation and death), Cathepsins C and B (lysosomal death pathway), Calpain 1 (endoplasmic reticulum stress), Calreticulin (apoptosis marker), Jun (early response) and Ahr (cell cycle arrest). Methods: Adult female rats were subjected to either intraorbital optic nerve transection (IONT) or intraorbital optic nerve crush (IONC). Protein from naive and ON injured adult rat retinas was extracted at increasing time-points post-lesion and western blotting experiments carried out. For immnuhistofluorescence analyses, retinal ganglion cells (RGCs) were retrogradelly identified with fluorogold applied to the superior colliculi one week before injury. Results: Western blotting analyses revealed up-regulation of all the analyzed proteins as soon as 12 hours post-lesion (hpl) peaking at 48hpl, in agreement with our previous RNA studies1. Furthermore, immunohistofluorescence to radial sections show that all of them, but Stat1, are expressed by the primarily injured neurons, the RGCs, as seen by colocalization with FG. Conclusions: All analyzed proteins were up-regulated in the retina after IONT or IONC as soon as 12hpl, indicating that ON injury regulates several branches of the apoptotic cascade and suggesting that commitment to death might be an earlier event than previously anticipated.
|
|
| 2. |
- Agudo, Marta, et al.
(författare)
-
Time course profiling of the retinal transcriptome after optic nerve transection and optic nerve crush
- 2008
-
Ingår i: Molecular Vision. - 1090-0535. ; 14, s. 1050-1063
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:A time-course analysis of gene regulation in the adult rat retina after intraorbital nerve crush (IONC) and intraorbital nerve transection (IONT).METHODS:RNA was extracted from adult rat retinas undergoing either IONT or IONC at increasing times post-lesion. Affymetrix RAE230.2 arrays were hybridized and analyzed. Statistically regulated genes were annotated and functionally clustered. Arrays were validated by means of quantative reverse transcription polymerase chain reaction (qRT-PCR) on ten regulated genes at two times post-lesion. Western blotting and immunohistofluorescence for four pro-apoptotic proteins were performed on naïve and injured retinas. Finally, custom signaling maps for IONT- and IONC-induced death response were generated (MetaCore, Genego Inc.).RESULTS:Here we show that over time, 3,219 sequences were regulated after IONT and 1,996 after IONC. Out of the total of regulated sequences, 1,078 were commonly regulated by both injuries. Interestingly, while IONT mainly triggers a gene upregulation-sustained over time, IONC causes a transitory downregulation. Functional clustering identified the regulation of high interest biologic processes, most importantly cell death wherein apoptosis was the most significant cluster. Ten death-related genes upregulated by both injuries were used for array validation by means of qRT-PCR. In addition, western blotting and immunohistofluorescence of total and active Caspase 3 (Casp3), tumor necrosis factor receptor type 1 associated death domain (TRADD), tumor necrosis factor receptor superfamily member 1a (TNFR1a), and c-fos were performed to confirm their protein regulation and expression pattern in naïve and injured retinas. These analyses demonstrated that for these genes, protein regulation followed transcriptional regulation and that these pro-apoptotic proteins were expressed by retinal ganglion cells (RGCs). MetaCore-based death-signaling maps show that several apoptotic cascades were regulated in the retina following optic nerve injury and highlight the similarities and differences between IONT and IONC in cell death profiling.CONCLUSIONS: This comprehensive time course retinal transcriptome study comparing IONT and IONC lesions provides a unique valuable tool to understand the molecular mechanisms underlying optic nerve injury and to design neuroprotective protocols.
|
|
| 3. |
- Apostolova, Galina, et al.
(författare)
-
Neurotransmitter phenotype-specific expression changes in developing sympathetic neurons
- 2007
-
Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 35:3, s. 397-408
-
Tidskriftsartikel (refereegranskat)abstract
- During late developmental phases individual sympathetic neurons undergo a switch from noradrenergic to cholinergic neurotransmission. This phenomenon of plasticity depends on target-derived signals in vivo and is triggered by neurotrophic factors in neuronal cultures. To analyze genome-wide expression differences between the two transmitter phenotypes we employed DNA microarrays. RNA expression profiles were obtained from chick paravertebral sympathetic ganglia, treated with neurotrophin 3, glial cell line-derived neurotrophic factor or ciliary neurotrophic factor, all of which stimulate cholinergic differentiation. Results were compared with the effect of nerve growth factor, which functions as a pro-noradrenergic stimulus. The gene set common to all three comparisons defined the noradrenergic and cholinergic synexpression groups. Several functional categories, such as signal transduction, G-protein-coupled signaling, cation transport, neurogenesis and synaptic transmission, were enriched in these groups. Experiments based on the prediction that some of the identified genes play a role in the neurotransmitter switch identified bone morphogenetic protein signaling as an inhibitor of cholinergic differentiation.
|
|
| 4. |
- Bakall, Benjamin, et al.
(författare)
-
Analysis of subcellular location of bestrophin in transfected RPE cell lines
- 2000
-
Ingår i: Gene Function and Disease. - 1438-7506 .- 1438-826X. ; 1:3-4, s. 128-133
-
Tidskriftsartikel (refereegranskat)abstract
- Best macular dystrophy is an autosomal dominant disease leading to macular degeneration and subsequent impaired vision. The disease has juvenile onset and affects the retinal pigment epithelium and adjacent photoreceptors. There are histopathological similarities between Best macular dystrophy (BMD) and age-related macular degeneration (AMD) with accumulation of lipofuscin in the outer retina. Recently, we identified the gene VMD2 causing Best macular dystrophy. The VMD2 gene has unknown function and there are no similarities between the VMD2 product, called bestrophin, and other proteins with known function. In order to gain more knowledge about the function of bestrophin we investigated its subcellular localization. DNA constructs encoding the bestrophin protein fused to the green fluorescent protein (GFP) or a c-myc tag were transiently expressed in COS-7 cells or retinal pigment epithelium cells. The observed pattern of bestrophin fusion protein was spotted and mainly perinuclear, well corresponding to the endoplasmic reticulum (ER), which was also suggested when counterstaining with an ER probe. Probes for other organelles had a different localization pattern compared to bestrophin. In conclusion, the results indicate that bestrophin is located to the endoplasmic reticulum.
|
|
| 5. |
- Blixt, Maria, 1984-, et al.
(författare)
-
A regulatory sequence from the retinoid X receptor gamma gene directs expression to horizontal cells and photoreceptors in the embryonic chicken retina
- 2016
-
Ingår i: Molecular Vision. - 1090-0535. ; 22, s. 1405-1420
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Combining techniques of episomal vector gene-specific Cre expression and genomic integration using the piggyBac transposon system enables studies of gene expression-specific cell lineage tracing in the chicken retina. In this work, we aimed to target the retinal horizontal cell progenitors. METHODS: A 208 bp gene regulatory sequence from the chicken retinoid X receptor gammagene (RXRgamma208) was used to drive Cre expression. RXRgamma is expressed in progenitors and photoreceptors during development. The vector was combined with a piggyBac "donor" vector containing a floxed STOP sequence followed by enhanced green fluorescent protein (EGFP), as well as a piggyBac helper vector for efficient integration into the host cell genome. The vectors were introduced into the embryonic chicken retina with in ovo electroporation. Tissue electroporation targets specific developmental time points and in specific structures. RESULTS: Cells that drove Cre expression from the regulatory RXRgamma208 sequence excised the floxed STOP-sequence and expressed GFP. The approach generated a stable lineage with robust expression of GFP in retinal cells that have activated transcription from the RXRgamma208 sequence. Furthermore, GFP was expressed in cells that express horizontal or photoreceptor markers when electroporation was performed between developmental stages 22 and 28. Electroporation of a stage 12 optic cup gave multiple cell types in accordance with RXRgamma gene expression in the early retina. CONCLUSIONS: In this study, we describe an easy, cost-effective, and time-efficient method for testing regulatory sequences in general. More specifically, our results open up the possibility for further studies of the RXRgamma-gene regulatory network governing the formation of photoreceptor and horizontal cells. In addition, the method presents approaches to target the expression of effector genes, such as regulators of cell fate or cell cycle progression, to these cells and their progenitor.
|
|
| 6. |
|
|
| 7. |
- Blixt, Maria K. E., et al.
(författare)
-
Zinc finger gene nolz1 regulates the formation of retinal progenitor cells and suppresses the Lim3/Lhx3 phenotype of retinal bipolar cells in chicken retina
- 2018
-
Ingår i: Developmental Dynamics. - : WILEY. - 1058-8388 .- 1097-0177. ; 247:4, s. 630-641
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The zinc-finger transcription factor Nolz1 regulates spinal cord neuron development by interacting with the transcription factors Isl1, Lim1, and Lim3, which are also important for photoreceptors, horizontal and bipolar cells during retinal development. We, therefore, studied Nolz1 during retinal development.Results: Nolz1 expression was seen in two waves during development: one early (peak at embryonic day 3-4.5) in retinal progenitors and one late (embryonic day 8) in newly differentiated cells in the inner nuclear layer. Overexpression and knockdown showed that Nolz1 decreases proliferation and stimulates cell cycle withdrawal in retinal progenitors with effects on the generation of retinal ganglion cells, photoreceptors, and horizontal cells without triggering apoptosis. Overexpression of Nolz1 gave more p27 positive cells. Sustained overexpression of Nolz1 in the retina gave fewer Lim3/Lhx3 bipolar cells.Conclusions: We conclude that Nolz1 has multiple functions during development and suggest a mechanism in which Nolz1 initially regulates the proliferation state of the retinal progenitor cells and then acts as a repressor that suppresses the Lim3/Lhx3 bipolar cell phenotype at the time of bipolar cell differentiation.
|
|
| 8. |
- Blixt, Maria, 1984-
(författare)
-
Keeping up with retinal photoreceptors and horizontal cells : Labelling and mapping of cells in the normal and diseased embryonic chicken retina
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The childhood eye cancer retinoblastoma originates from the retina and its development is initiated while the foetus is in the uterus. Retinoblastoma has a reported incidence of 1 in 15-18 000 live births, and approximately 90% of all patients are diagnosed before the age of 5. The occurrence of retinoblastoma is usually detected by the parents and the most frequent symptoms are leukocoria (white pupillary reflex), strabismus (squinting) or if the child complains of visual problems. Retinoblastoma is diagnosed by examination under anaesthesia and documentation by RetCam. It is treated with various cytostatic agents, or by laser. If the treatment is unsuccessful, or there is a risk that the tumour cells will spread and form metastases, the eye is removed.Previous studies have indicated that the cell type from which the tumour arises, the cell-of-origin, may be the cone photoreceptors and/or their immediate interneuron, the horizontal cells. Determining the cell-of-origin for retinoblastoma is an important goal, however, understanding the molecular mechanisms that distinguish the photoreceptors and the horizontal cells from the other retinal cells may prove just as important for understanding this disease.The aim of my project has been to develop, optimise and validate methods to label, map and target expression to photoreceptors and horizontal cells in the chicken embryonic retina. We have successfully established several methods that test the expression pattern of conserved, regulatory DNA sequences, and have performed short- and long-term expression of various genes that have been reported to be involved in cell cycle regulation and cell fate determination. One of my most important findings was that a region from the RXRγ gene allowed us to specifically target the photoreceptors and horizontal cells. Our previous knowledge, together with the newly established tools, puts us an important step closer towards understanding the development and behaviour of the retinal photoreceptors and horizontal cells, however, further studies are of course needed.
|
|
| 9. |
|
|
| 10. |
- Blixt, Maria, et al.
(författare)
-
MYCN induces cell-specific tumorigenic growth in RB1-proficient human retinal organoid and chicken retina models of retinoblastoma
- 2022
-
Ingår i: Oncogenesis. - : Springer Science and Business Media LLC. - 2157-9024. ; 11:1, s. 34-
-
Tidskriftsartikel (refereegranskat)abstract
- Retinoblastoma is a rare, intraocular paediatric cancer that originates in the neural retina and is most frequently caused by bi-allelic loss of RB1 gene function. Other oncogenic mutations, such as amplification and increased expression of the MYCN gene, have been found even with proficient RB1 function. In this study, we investigated whether MYCN over-expression can drive carcinogenesis independently of RB1 loss-of-function mutations. The aim was to elucidate the events that result in carcinogenesis and identify the cancer cell-of-origin. We used the chicken retina, a well-established model for studying retinal neurogenesis, and established human embryonic stem cell-derived retinal organoids as model systems. We over-expressed MYCN by electroporation of piggyBac genome-integrating expression vectors. We found that over-expression of MYCN induced tumorigenic growth with high frequency in RB1-proficient chicken retinas and human organoids. In both systems, the tumorigenic cells expressed markers for undifferentiated cone photoreceptor/horizontal cell progenitors. The over-expression resulted in metastatic retinoblastoma within 7–9 weeks in chicken. Cells expressing MYCN could be grown in vitro and, when orthotopically injected, formed tumours that infiltrated the sclera and optic nerve and expressed markers for cone progenitors. Investigation of the tumour cell phenotype determined that the potential for neoplastic growth was embryonic stage-dependent and featured a cell-specific resistance to apoptosis in the cone/horizontal cell lineage, but not in ganglion or amacrine cells. We conclude that MYCN over-expression is sufficient to drive tumorigenesis and that a cell-specific resistance to apoptosis in the cone/horizontal cell lineage mediates the cancer phenotype.
|
|
