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Harun-Or-Rashid, MohammadORCID iD iconorcid.org/Save personal data »
Publications (10 of 10) Show all publications
Harun-Or-Rashid, M. & Hallböök, F. (2019). Alpha 2-Adrenergic Receptor Agonist Brimonidine Stimulates ERK1/2 and AKT Signaling via Transactivation of EGF Receptors in the Human MIO-M1 Müller Cell Line. Current Eye Research, 44(1), 34-45
Open this publication in new window or tab >>Alpha 2-Adrenergic Receptor Agonist Brimonidine Stimulates ERK1/2 and AKT Signaling via Transactivation of EGF Receptors in the Human MIO-M1 Müller Cell Line
2019 (English)In: Current Eye Research, ISSN 0271-3683, E-ISSN 1460-2202, Vol. 44, no 1, p. 34-45Article in journal (Refereed) Published
Abstract [en]

Purpose: Alpha 2-adrenergic receptor (α2-ADR) agonists are used clinically for a range of indications including reducing elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension. Animal experiments show that α2-ADR agonists attenuate the injury-induced Müller cell dedifferentiation by a mechanism that involves activation and regulation of extracellular signal-regulated kinase (ERK) 1/2 leading to transactivation of epidermal growth factor receptors (EGFRs). The purpose of this study was to study and corroborate the activation of this system in human cells.

Material and Methods: The human Müller cell line MIO-M1 was treated with the α2A-ADR agonist brimonidine in combination with inhibitors for Src-kinase, EGFR-kinase, matrix metalloproteinase (MMP) as well as small interfering RNAs (siRNAs) for the EGFR. The cells were analyzed using immunocytochemistry, quantitative PCR and western blot techniques.

Results: Our results show that human MIO-M1 cells express α2A-ADRs and that stimulation of these receptors caused a robust increase of ERK1/2 and protein kinase B (PKB/AKT) (Thr-308) phosphorylation in MIO-M1 cells. P-ERK1/2 and P-AKT (Thr-308) signaling was mediated by Src-kinase and associated with phosphorylation of tyrosine residue of epidermal growth factor receptor (P-EGFR Y1173). In addition, the agonist caused activation of MMPs. These effects could be blocked by Src-kinase inhibitors (PP1, PP2), EGFR-kinase inhibitor (AG1478), EGFR-siRNA and a MMP inhibitor (GM6001).

Conclusion: The results confirm that this human Müller cell line responds to ADR stimulation with phosphorylation of ERK and AKT, which suggests that it is possible to pharmacologically target ADR to modulate the early events in human Müller cell dedifferentiation in a similar fashion as been shown for chicken Müller cells.

Abbreviations: CRALBP: cellular retinaldehyde binding protein; EGFR: epidermal growth factor receptor; ERK1/2: extracellular signal-regulated kinase 1/2; GS: glutamine synthetase; GPCR: G protein-coupled receptor; IR: immunoreactivity; MAPK: mitogen-activated protein kinase; MMP: matrix metalloproteinase; P-ERK1/2: phospho-ERK1/2; qRT-PCR: quantitative reverse transcriptase PCR

Keywords
AKT pathway, Alpha 2-adrenergic receptors, Brimonidine, EGF receptor, ERK1/2, Matrix metalloproteinases, MIO-M1 human Müller cell, and Src-kinase
National Category
Neurosciences
Research subject
Medical Science
Identifiers
urn:nbn:se:uu:diva-281576 (URN)10.1080/02713683.2018.1516783 (DOI)000454952100006 ()30198788 (PubMedID)
Funder
Swedish Research Council, 2016-01641
Note

Title in thesis list of papers: Alpha2-Adrenergic Agonist Brimonidine Stimulates ERK1/2 and AKT Signaling Via Transactivation of EGF Receptors in MIO-M1 Human Müller Cells

Available from: 2016-03-24 Created: 2016-03-24 Last updated: 2019-01-25Bibliographically approved
Harun-Or-Rashid, M., Konjusha, D., Galindo-Romero, C. & Hallböök, F. (2016). Endothelin B Receptors on Primary Chicken Müller Cells and the Human MIO-M1 Müller Cell Line Activate ERK Signaling via Transactivation of Epidermal Growth Factor Receptors. PLoS ONE, 11(12), Article ID e0167778.
Open this publication in new window or tab >>Endothelin B Receptors on Primary Chicken Müller Cells and the Human MIO-M1 Müller Cell Line Activate ERK Signaling via Transactivation of Epidermal Growth Factor Receptors
2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 12, article id e0167778Article in journal (Refereed) Published
Abstract [en]

Injury to the eye or retina triggers Muller cells, the major glia cell of the retina, to dedifferentiate and proliferate. In some species they attain retinal progenitor properties and have the capacity to generate new neurons. The epidermal growth factor receptor (EGFR) system and extracellular signal-regulated kinase (ERK) signaling are key regulators of these processes in Muller cells. The extracellular signals that modulate and control these processes are not fully understood. In this work we studied whether endothelin receptor signaling can activate EGFR and ERK signaling in Muller cells. Endothelin expression is robustly upregulated at retinal injury and endothelin receptors have been shown to transactivate EGFRs in other cell types. We analyzed the endothelin signaling system in chicken retina and cultured primary chicken Muller cells as well as the human Muller cell line MIO-M1. The Muller cells were stimulated with receptor agonists and treated with specific blockers to key enzymes in the signaling pathway or with siRNAs. We focused on endothelin receptor mediated transactivation of EGFRs by using western blot analysis, quantitative reverse transcriptase PCR and immunocytochemistry. The results showed that chicken Muller cells and the human Muller cell line MIO-M1 express endothelin receptor B. Stimulation by the endothelin receptor B agonist IRL1620 triggered phosphorylation of ERK1/2 and autophosphorylation of (Y1173) EGFR. The effects could be blocked by Src-kinase inhibitors (PP1, PP2), EGFR-inhibitor (AG1478), EGFR-siRNA and by inhibitors to extracellular matrix metalloproteinases (GM6001), consistent with a Src-kinase mediated endothelin receptor response that engage ligand-dependent and ligand-independent EGFR activation. Our data suggest a mechanism for how injury-induced endothelins, produced in the retina, may modulate the Muller cell responses by Src-mediated transactivation of EGFRs. The data give support to a view in which endothelins among several other functions, serve as an injury-signal that regulate the gliotic response of Muller cells.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-312630 (URN)10.1371/journal.pone.0167778 (DOI)000389580900045 ()27930693 (PubMedID)
Funder
Swedish Research Council, M 12187
Available from: 2017-01-26 Created: 2017-01-12 Last updated: 2017-11-29Bibliographically approved
Harun-Or-Rashid, M. (2016). Modulation of the Progenitor Cell and Homeostatic Capacities of Müller Glia Cells in Retina: Focus on α2-Adrenergic and Endothelin Receptor Signaling Systems. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Modulation of the Progenitor Cell and Homeostatic Capacities of Müller Glia Cells in Retina: Focus on α2-Adrenergic and Endothelin Receptor Signaling Systems
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Müller cells are major glial cells in the retina and have a broad range of functions that are vital for the retinal neurons. During retinal injury gliotic response either leads to Müller cell dedifferentiation and formation of a retinal progenitor or to maintenance of mature Müller cell functions. The overall aim of this thesis was to investigate the intra- and extracellular signaling of Müller cells, to understand how Müller cells communicate during an injury and how their properties can be regulated after injury. Focus has been on the α2-adrenergic receptor (α2-ADR) and endothelin receptor (EDNR)-induced modulation of Müller cell-properties after injury.

The results show that α2-ADR stimulation by brimonidine (BMD) triggers Src-kinase mediated ligand-dependent and ligand-independent transactivation of epidermal growth factor receptor (EGFR) in both chicken and human Müller cells. The effects of this transactivation in injured retina attenuate injury-induced activation and dedifferentiation of Müller cells by attenuating injury-induced ERK signaling. The attenuation was concomitant with a synergistic up-regulation of negative ERK- and RTK-feedback regulators during injury. The data suggest that adrenergic stress-signals modulate glial responses during retinal injury and that α2-ADR pharmacology can be used to modulate glial injury-response. We studied the effects of this attenuation of Müller cell dedifferentiation on injured retina from the perspective of neuroprotection. We analyzed retinal ganglion cell (RGC) survival after α2-ADR stimulation of excitotoxically injured chicken retina and our results show that α2-ADR stimulation protects RGCs against the excitotoxic injury. We propose that α2-ADR-induced protection of RGCs in injured retina is due to enhancing the attenuation of the glial injury response and to sustaining mature glial functions. Moreover, we studied endothelin-induced intracellular signaling in Müller cells and our results show that stimulation of EDNRB transactivates EGFR in Müller cells in a similar way as seen after α2-ADR stimulation. These results outline a mechanism of how injury-induced endothelins may modulate the gliotic responses of Müller cells.

The results obtained in this thesis are pivotal and provide new insights into glial functions, thereby uncovering possibilities to target Müller cells by designing neuroprotective treatments of retinal degenerative diseases or acute retinal injury.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. p. 73
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1201
Keywords
Alpha2-adrenergic receptor, Brimonidine, Brn3a, Dedifferentiation, Endothelin, EGFR, ERK1/2, Neuroprotection, NMDA, MIO-M1 human Müller cell, Müller cells, Retina, Retinal ganglion cells, Src-kinase, Transactivation.
National Category
Neurosciences
Research subject
Medical Science
Identifiers
urn:nbn:se:uu:diva-281569 (URN)978-91-554-9527-5 (ISBN)
Public defence
2016-05-19, B21, BMC, Husagatan 03, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2016-04-28 Created: 2016-03-24 Last updated: 2018-01-10
Dorshorst, B., Harun-Or-Rashid, M., Bagherpoor, A. J., Rubin, C.-J., Ashwell, C., Gourichon, D., . . . Andersson, L. (2015). A Genomic Duplication is Associated with Ectopic Eomesodermin Expression in the Embryonic Chicken Comb and Two Duplex-comb Phenotypes. PLOS Genetics, 11(3), Article ID e1004947.
Open this publication in new window or tab >>A Genomic Duplication is Associated with Ectopic Eomesodermin Expression in the Embryonic Chicken Comb and Two Duplex-comb Phenotypes
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2015 (English)In: PLOS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 11, no 3, article id e1004947Article in journal (Refereed) Published
Abstract [en]

Duplex-comb (D) is one of three major loci affecting comb morphology in the domestic chicken. Here we show that the two Duplex-comb alleles, V-shaped (D*V) and Buttercup (D*C), are both associated with a 20 Kb tandem duplication containing several conserved putative regulatory elements located 200 Kb upstream of the eomesodermin gene (EOMES). EOMES is a T-box transcription factor that is involved in mesoderm specification during gastrulation. In D*V and D*C chicken embryos we find that EOMES is ectopically expressed in the ectoderm of the comb-developing region as compared to wild-type embryos. The confinement of the ectopic expression of EOMES to the ectoderm is in stark contrast to the causal mechanisms underlying the two other major comb loci in the chicken (Rose-comb and Pea-comb) in which the transcription factors MNR2 and SOX5 are ectopically expressed strictly in the mesenchyme. Interestingly, the causal mutations of all three major comb loci in the chicken are now known to be composed of large-scale structural genomic variants that each result in ectopic expression of transcription factors. The Duplex-comb locus also illustrates the evolution of alleles in domestic animals, which means that alleles evolve by the accumulation of two or more consecutive mutations affecting the phenotype. We do not yet know whether the V-shaped or Buttercup allele correspond to the second mutation that occurred on the haplotype of the original duplication event.

National Category
Medical Genetics
Identifiers
urn:nbn:se:uu:diva-248610 (URN)10.1371/journal.pgen.1004947 (DOI)000352197100002 ()25789773 (PubMedID)
Available from: 2015-04-02 Created: 2015-04-02 Last updated: 2018-01-11Bibliographically approved
Harun-Or-Rashid, M., Diaz-DelCastillo, M., Galindo-Romero, C. & Hallböök, F. (2015). Alpha2-Adrenergic-Agonist Brimonidine Stimulates Negative Feedback and Attenuates Injury-Induced Phospho-ERK and Dedifferentiation of Chicken Müller Cells. Investigative Ophthalmology and Visual Science, 56(10), 5933-5945
Open this publication in new window or tab >>Alpha2-Adrenergic-Agonist Brimonidine Stimulates Negative Feedback and Attenuates Injury-Induced Phospho-ERK and Dedifferentiation of Chicken Müller Cells
2015 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 56, no 10, p. 5933-5945Article in journal (Refereed) Published
Abstract [en]

Purpose:

Retinal injury induces Müller cell dedifferentiation by activating extracellular signal-regulated kinase (ERK) signaling. Stimulation of α2-adrenergic receptors protects against injury but also activates ERK in Müller cells. The purpose of this work was to study the effect of α2-adrenergic signaling on injury-induced ERK and Müller cell dedifferentiation. We tested the hypothesis that α2-stimulation triggers negative feedback regulation of the injury-induced ERK pathway that attenuates Müller cell dedifferentiation.

Methods:

Chicken retina injured by N-methyl-D-aspartate and cultured primary Müller cells were stimulated by the α2-adrenergic agonist brimonidine. Immunostaining, quantitative RT-PCR, and Western blot techniques in combination with receptor blockers were used for analysis of the cellular responses.

Results:

Alpha2-adrenergic receptor stimulation attenuated injury-induced ERK activation and dedifferentiation of Müller cells as seen by decreased phospho-ERK, expression of transitin, and retinal progenitor cell genes. The attenuation was concomitant with a synergistic upregulation of several negative ERK-signal feedback regulators including ERK-phosphatases, Raf1-, and growth factor receptor–binding proteins. The results were also seen in cultures of primary Müller cells.

Conclusions:

Alpha2-adrenergic signaling on Müller cells elicits an intracellular attenuation of the injury response that comprises negative ERK-signaling feedback leading to attenuated Müller cell dedifferentiation. The implications of this study are that adrenergic stress signals may directly modulate glial function in retina and that α2-adrenergic receptor pharmacology may be used to control glial injury response.

National Category
Neurosciences
Identifiers
urn:nbn:se:uu:diva-262700 (URN)10.1167/iovs.15-16816 (DOI)000368426300032 ()
Funder
Swedish Research Council, M 12187
Available from: 2015-09-18 Created: 2015-09-18 Last updated: 2018-01-11Bibliographically approved
Harun-Or-Rashid, M., Lindqvist, N. & Hallböök, F. (2014). Transactivation of EGF Receptors in Chicken Muller Cells by α2A-Adrenergic Receptors Stimulated by Brimonidine. Investigative Ophthalmology and Visual Science, 55(6), 3385-3394
Open this publication in new window or tab >>Transactivation of EGF Receptors in Chicken Muller Cells by α2A-Adrenergic Receptors Stimulated by Brimonidine
2014 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 55, no 6, p. 3385-3394Article in journal (Refereed) Published
Abstract [en]

Purpose: α2-Adrenergic receptor agonists are used in glaucoma treatment and have been shown to have some neuroprotective effects. We performed this study to test the hypothesis that epidermal growth factor receptors on chicken Müller cells are transactivated by α2-adrenergic receptors and we focused on the extracellular signal-activated kinases 1/2 (ERK) pathway. Methods: Embryonic chicken retina and cultures of primary Müller cells were stimulated by α2-adrenergic receptor agonist brimonidine. Immunostaining, qRT-PCR and western blot techniques in combination with Src-, epidermal growth factor receptor kinase-, and matrix metalloproteinase inhibitors were used for analysis of the cellular responses. Results: Our results showed that Müller cells express α2A-adrenergic receptors in vivo and in vitro and that brimonidine triggered a robust and transient phosphorylation of ERK1/2. This ERK-response was Src-kinase dependent, associated with tyrosine phosphorylation of epidermal growth factor receptors (phospho-Y1068, Y1173) and was mediated by matrix metalloproteinase-activity on the Müller cells. Conclusions: Müller cells express the α2A-adrenergic receptor and brimonidine triggers both Src-kinase- and matrix metalloproteinase-mediated autocrine ligand-dependent activation of epidermal growth factor receptors on Müller cell. This response is consistent with transactivation of epidermal growth factor receptors by stimulation of α2-adrenergic receptors.

National Category
Ophthalmology
Identifiers
urn:nbn:se:uu:diva-224134 (URN)10.1167/iovs.13-13823 (DOI)000339485800003 ()24781942 (PubMedID)
Available from: 2014-05-05 Created: 2014-05-05 Last updated: 2017-12-05Bibliographically approved
Zang, G., Christoffersson, G., Tian, G., Harun-Or-Rashid, M., Vågesjö, E., Phillipson, M., . . . Welsh, M. (2013). Aberrant association between vascular endothelial growth factor receptor-2 and VE-cadherin in response to vascular endothelial growth factor-a in Shb-deficient lung endothelial cells. Cellular Signalling, 25(1), 85-92
Open this publication in new window or tab >>Aberrant association between vascular endothelial growth factor receptor-2 and VE-cadherin in response to vascular endothelial growth factor-a in Shb-deficient lung endothelial cells
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2013 (English)In: Cellular Signalling, ISSN 0898-6568, E-ISSN 1873-3913, Vol. 25, no 1, p. 85-92Article in journal (Refereed) Published
Abstract [en]

Vascular permeability is a hallmark response to the main angiogenic factor VEGF-A and we have previously described a reduction of this response in Shb knockout mice. To characterize the molecular mechanisms responsible for this effect, endothelial cells were isolated from lungs and analyzed in vitro. Shb deficient endothelial cells exhibited less migration in a scratch wound-healing assay both under basal conditions and after vascular endothelial growth factor-A (VEGF-A) stimulation, suggesting a functional impairment of these cells in vitro. Staining for VE-cadherin and vascular endothelial growth factor receptor-2 (VEGFR-2) showed co-localization in adherens junctions and in intracellular sites such as the perinuclear region in wild-type and Shb knockout cells. VEGF-A decreased the VE-cadherin/VEGFR-2 co-localization in membrane structures resembling adherens junctions in wild-type cells whereas no such response was noted in the Shb knockout cells. VE-cadherin/VEGFR-2 co-localization was also recorded using spinning-disc confocal microscopy and VEGF-A caused a reduced association in the wild-type cells whereas the opposite pattern was observed in the Shb knockout cells. The latter expressed slightly more of cell surface VEGFR-2. VEGF-A stimulated extracellular-signal regulated kinase, Akt and Rac1 activities in the wild-type cells whereas no such responses were noted in the knockout cells. We conclude that aberrant signaling characteristics with respect to ERK, Akt and Rac1 are likely explanations for the observed altered pattern of VE-cadherin/VEGFR-2 association. The latter is important for understanding the reduced in vivo vascular permeability response in Shb knockout mice, a phenomenon that has patho-physiological relevance.

Keywords
Vascular endothelial growth factor receptor-2, VE-cadherin, adherens junctions, Shb, signal-transduction, Rac1
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-181357 (URN)10.1016/j.cellsig.2012.09.018 (DOI)000312616900010 ()
Note

De 2 första författarna delar förstaförfattarskapet.

Available from: 2012-09-24 Created: 2012-09-21 Last updated: 2019-02-01Bibliographically approved
Ka, S., Markljung, E., Ring, H., Albert, F. W., Harun-Or-Rashid, M., Wahlberg, P., . . . Hallböök, F. (2013). The expression of carnitine palmitoyl-CoA transferase-1B is influenced by a cis-acting eQTL in two chicken lines selected for high and low body weight. Physiological Genomics, 45(9), 367-376
Open this publication in new window or tab >>The expression of carnitine palmitoyl-CoA transferase-1B is influenced by a cis-acting eQTL in two chicken lines selected for high and low body weight
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2013 (English)In: Physiological Genomics, ISSN 1094-8341, E-ISSN 1531-2267, Vol. 45, no 9, p. 367-376Article in journal (Refereed) Published
Abstract [en]

Carnitine palmitoyl-CoA transferase-1B is a mitochondrial enzyme in the fatty acid oxidation pathway. In a previous study, CPT1B was identified as differentially expressed in the hypothalamus of two lines of chickens established by long-term selection for high (HWS) or low (LWS) body weight. Mammals have three paralogs (CPT1a, b and c) while non-mammalian vertebrates only have two (CPT1A, B). CPT1A is expressed in liver and CPT1B in muscle. CPT1c is expressed in hypothalamus, where it regulates feeding and energy expenditure. We identified an intronic length polymorphism, fixed for different alleles in the two populations and mapped the hitherto missing CPT1B locus in the chicken genome assembly, to the distal tip of chromosome 1p. Based on molecular phylogeny and gene synteny we suggest that chicken CPT1B is pro-orthologous of the mammalian CPT1c. Chicken CPT1B was differentially expressed in both muscle and hypothalamus but in opposite directions: higher levels in hypothalamus but lower levels in muscle in the HWS than in the LWS line. Using an advanced inter-cross population of the lines, CPT1B expression was found to be influenced by a cis-acting expression quantitative trait locus in muscle. The increased expression in hypothalamus and reduced expression in muscle is consistent with an increased food intake in the HWS line and at the same time reduced fatty acid oxidation in muscle yielding a net accumulation of energy intake and storage. The altered expression of CPT1B in hypothalamus and peripheral tissue is likely to be a mechanism contributing to the remarkable difference between lines.

National Category
Clinical Medicine
Identifiers
urn:nbn:se:uu:diva-197716 (URN)10.1152/physiolgenomics.00078.2012 (DOI)000318265700003 ()23512741 (PubMedID)
Available from: 2013-04-02 Created: 2013-04-02 Last updated: 2017-12-06Bibliographically approved
Boije, H., Harun-Or-Rashid, M., Lee, Y.-J., Imsland, F., Bruneau, N., Vieaud, A., . . . Hallböök, F. (2012). Sonic Hedgehog-Signalling Patterns the Developing Chicken Comb as Revealed by Exploration of the Pea-comb Mutation. PLoS ONE, 7(12), e50890
Open this publication in new window or tab >>Sonic Hedgehog-Signalling Patterns the Developing Chicken Comb as Revealed by Exploration of the Pea-comb Mutation
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2012 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 12, p. e50890-Article in journal (Refereed) Published
Abstract [en]

The genetic basis and mechanisms behind the morphological variation observed throughout the animal kingdom is stillrelatively unknown. In the present work we have focused on the establishment of the chicken comb-morphology byexploring the Pea-comb mutant. The wild-type single-comb is reduced in size and distorted in the Pea-comb mutant. Peacombis formed by a lateral expansion of the central comb anlage into three ridges and is caused by a mutation in SOX5,which induces ectopic expression of the SOX5 transcription factor in mesenchyme under the developing comb. Analysis ofdifferential gene expression identified decreased Sonic hedgehog (SHH) receptor expression in Pea-comb mesenchyme. Byexperimentally blocking SHH with cyclopamine, the wild-type single-comb was transformed into a Pea-comb-likephenotype. The results show that the patterning of the chicken comb is under the control of SHH and suggest that ectopicSOX5 expression in the Pea-comb change the response of mesenchyme to SHH signalling with altered combmorphogenesis as a result. A role for the mesenchyme during comb morphogenesis is further supported by the recentfinding that another comb-mutant (Rose-comb), is caused by ectopic expression of a transcription factor in combmesenchyme. The present study does not only give knowledge about how the chicken comb is formed, it also adds to ourunderstanding how mutations or genetic polymorphisms may contribute to inherited variations in the human face.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-187458 (URN)10.1371/journal.pone.0050890 (DOI)000312588200079 ()
Available from: 2012-12-07 Created: 2012-12-06 Last updated: 2017-12-07Bibliographically approved
Harun-Or-Rashid, M., Konjusha, D., Galindo-Romero, C. & Hallböök, F.The Endothelin B Receptor Transactivates Epidermal Growth Factor Receptors in primary chicken Müller cells and in MIO-M1 Human Müller Cells.
Open this publication in new window or tab >>The Endothelin B Receptor Transactivates Epidermal Growth Factor Receptors in primary chicken Müller cells and in MIO-M1 Human Müller Cells
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Injury to the nervous system elicits signals that trigger a variety of cellular responses. Injury to the retina triggers Müller cells, the major glia cell of the retina, to dedifferentiate, proliferate, attain retinal progenitor properties and in some species generate new neurons. The epidermal growth factor receptor (EGFR) system and extracellular signal-regulated kinase (ERK) signalling are key regulators of these processes in Müller cells. The complexity of the extracellular signals that modulate and control the process are not fully understood. In this work we studied whether endothelin receptor signalling can activate EGFR and ERK signalling in Müller cells. Endothelin expression is robustly up-regulated at retinal injury and endothelin receptors have been shown to transactivate EGFRs in other cell-types. We treated chicken Müller cells in vivo, cultured primary chicken Müller cells and the human Müller cell line MIO-M1 with receptor agonists and enzyme blockers, and analyzed endothelin receptor mediated transactivation of EGFRs by using western blot analysis, quantitative reverse transcriptase PCR and immunocytochemistry. The results showed that both chicken and human Müller cells express endothelin receptor B. Stimulation by using the endothelin receptor B agonist IRL1620 caused Src-kinase mediated ligand-dependent and ligand-independent EGFR transactivation. The effects could be blocked by Src-kinase inhibitors (PP1, PP2), EGFR inhibitor (AG1478) and by inhibitors to extracellular matrix metalloproteinases (GM6001). Our data outline a mechanism how injury-induced endothelins may modulate the Müller cell responses by transactivation of EGFRs. The data give support to a view in which endothelins, among several other functions, serve as an injury-signal that regulate the gliotic response of Müller cells.

Keywords
AG1478, endothelin receptor B agonist IRL1620, ERK1/2, gliosis, matrix-metalloproteinases, MAPK, N-methyl-D-aspartate, excitotoxic retinal injury, Src-kinase
National Category
Neurosciences
Research subject
Medical Science
Identifiers
urn:nbn:se:uu:diva-281586 (URN)
Available from: 2016-03-24 Created: 2016-03-24 Last updated: 2018-01-10
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