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Regulation of retinoid receptors by retinoic acid and axonal contact in Schwann cells.

Latasa MJ, Cosgaya JM - PLoS ONE (2011)

Bottom Line: As retinoic acid (RA) and other retinoids have a profound effect as regulators of the myelination program, we sought to investigate how their nuclear receptors levels were regulated in this cell type.The upregulation by axonal contact mimickers and the transcriptional downregulation by RA were dependent on de novo protein synthesis and did not involve changes in mRNA stability.All together, our results show that retinoid receptors are regulated in a complex manner in Schwann cells, suggesting that they could have a prominent role as regulators of Schwann cell physiology.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrine and Nervous System Physiopathology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain.

ABSTRACT

Background: Schwann cells (SCs) are the cell type responsible for the formation of the myelin sheath in the peripheral nervous system (PNS). As retinoic acid (RA) and other retinoids have a profound effect as regulators of the myelination program, we sought to investigate how their nuclear receptors levels were regulated in this cell type.

Methodology/principal findings: In the present study, by using Schwann cells primary cultures from neonatal Wistar rat pups, as well as myelinating cocultures of Schwann cells with embryonic rat dorsal root ganglion sensory neurons, we have found that sustained expression of RXR-γ depends on the continuous presence of a labile activator, while axonal contact mimickers produced an increase in RXR-γ mRNA and protein levels, increment that could be prevented by RA. The upregulation by axonal contact mimickers and the transcriptional downregulation by RA were dependent on de novo protein synthesis and did not involve changes in mRNA stability. On the other hand, RAR-β mRNA levels were only slightly modulated by axonal contact mimickers, while RA produced a strong transcriptional upregulation that was independent of de novo protein synthesis without changes in mRNA stability.

Conclusions/significance: All together, our results show that retinoid receptors are regulated in a complex manner in Schwann cells, suggesting that they could have a prominent role as regulators of Schwann cell physiology.

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Related in: MedlinePlus

RA upregulates RAR-β mRNA and downregulates RXR-γ mRNA in isolated SCs.SCs were treated with 1 µM RA for the times indicated and the relative levels of all six retinoid receptors were determined by Q-RT-PCR. All values are shown as the mean ± SD relative to their respective controls.
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pone-0017023-g005: RA upregulates RAR-β mRNA and downregulates RXR-γ mRNA in isolated SCs.SCs were treated with 1 µM RA for the times indicated and the relative levels of all six retinoid receptors were determined by Q-RT-PCR. All values are shown as the mean ± SD relative to their respective controls.

Mentions: SCs were isolated and purified as previously indicated [30]. After cytosine arabinoside and Thy-1.1 purification, SCs cultures were plated in poly-L-Lysine-coated plates and expanded in 10% heat-inactivated fetal bovine serum (FBS)-containing Dulbecco's modified Eagle's medium (DMEM), in the continuous presence of 2 µM forskolin (Calbiochem) and 60 µg/ml bovine pituitary extract (BPE; Gibco). Cultures were always used within less than four passages and all experiments were repeated with SCs from different preparations. For experiments, freshly seeded SCs were allowed to attach O.N. in regular media, changed to DMEM containing 10% of newborn bovine serum (NBS) depleted of retinoids (achieved by sequential incubations with AG1-X8 resin and charcoal), in the presence of 2 µM forskolin and 60 µg/ml BPE. When the effect of BPE and/or forskolin was to be analyzed, these factors were removed form the cell culture media already at the time of seeding and the cultures were allowed to adapt to the new conditions for at least 24 hours before adding the different treatments. In any case, controls were always treated with an equivalent amount of vehicle (0.01% ethanol for a typical 1 µM RA treatment) for the same time. The data depicted in Figure 5 is a reverse time-course in with all the samples were processed at the same time, having been treated with the retinoid for the time indicated in the X-axis. Control cultures were treated with vehicle (0.01% ethanol) for the longest time point analyzed (48 hours).


Regulation of retinoid receptors by retinoic acid and axonal contact in Schwann cells.

Latasa MJ, Cosgaya JM - PLoS ONE (2011)

RA upregulates RAR-β mRNA and downregulates RXR-γ mRNA in isolated SCs.SCs were treated with 1 µM RA for the times indicated and the relative levels of all six retinoid receptors were determined by Q-RT-PCR. All values are shown as the mean ± SD relative to their respective controls.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046125&req=5

pone-0017023-g005: RA upregulates RAR-β mRNA and downregulates RXR-γ mRNA in isolated SCs.SCs were treated with 1 µM RA for the times indicated and the relative levels of all six retinoid receptors were determined by Q-RT-PCR. All values are shown as the mean ± SD relative to their respective controls.
Mentions: SCs were isolated and purified as previously indicated [30]. After cytosine arabinoside and Thy-1.1 purification, SCs cultures were plated in poly-L-Lysine-coated plates and expanded in 10% heat-inactivated fetal bovine serum (FBS)-containing Dulbecco's modified Eagle's medium (DMEM), in the continuous presence of 2 µM forskolin (Calbiochem) and 60 µg/ml bovine pituitary extract (BPE; Gibco). Cultures were always used within less than four passages and all experiments were repeated with SCs from different preparations. For experiments, freshly seeded SCs were allowed to attach O.N. in regular media, changed to DMEM containing 10% of newborn bovine serum (NBS) depleted of retinoids (achieved by sequential incubations with AG1-X8 resin and charcoal), in the presence of 2 µM forskolin and 60 µg/ml BPE. When the effect of BPE and/or forskolin was to be analyzed, these factors were removed form the cell culture media already at the time of seeding and the cultures were allowed to adapt to the new conditions for at least 24 hours before adding the different treatments. In any case, controls were always treated with an equivalent amount of vehicle (0.01% ethanol for a typical 1 µM RA treatment) for the same time. The data depicted in Figure 5 is a reverse time-course in with all the samples were processed at the same time, having been treated with the retinoid for the time indicated in the X-axis. Control cultures were treated with vehicle (0.01% ethanol) for the longest time point analyzed (48 hours).

Bottom Line: As retinoic acid (RA) and other retinoids have a profound effect as regulators of the myelination program, we sought to investigate how their nuclear receptors levels were regulated in this cell type.The upregulation by axonal contact mimickers and the transcriptional downregulation by RA were dependent on de novo protein synthesis and did not involve changes in mRNA stability.All together, our results show that retinoid receptors are regulated in a complex manner in Schwann cells, suggesting that they could have a prominent role as regulators of Schwann cell physiology.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrine and Nervous System Physiopathology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain.

ABSTRACT

Background: Schwann cells (SCs) are the cell type responsible for the formation of the myelin sheath in the peripheral nervous system (PNS). As retinoic acid (RA) and other retinoids have a profound effect as regulators of the myelination program, we sought to investigate how their nuclear receptors levels were regulated in this cell type.

Methodology/principal findings: In the present study, by using Schwann cells primary cultures from neonatal Wistar rat pups, as well as myelinating cocultures of Schwann cells with embryonic rat dorsal root ganglion sensory neurons, we have found that sustained expression of RXR-γ depends on the continuous presence of a labile activator, while axonal contact mimickers produced an increase in RXR-γ mRNA and protein levels, increment that could be prevented by RA. The upregulation by axonal contact mimickers and the transcriptional downregulation by RA were dependent on de novo protein synthesis and did not involve changes in mRNA stability. On the other hand, RAR-β mRNA levels were only slightly modulated by axonal contact mimickers, while RA produced a strong transcriptional upregulation that was independent of de novo protein synthesis without changes in mRNA stability.

Conclusions/significance: All together, our results show that retinoid receptors are regulated in a complex manner in Schwann cells, suggesting that they could have a prominent role as regulators of Schwann cell physiology.

Show MeSH
Related in: MedlinePlus