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Selective survival and maturation of adult-born dentate granule cells expressing the immediate early gene Arc/Arg3.1.

Kuipers SD, Tiron A, Soule J, Messaoudi E, Trentani A, Bramham CR - PLoS ONE (2009)

Bottom Line: Contrary to expectation, LTP did not induce Arc expression in newborn cells at any age, suggesting they might be refractory to synaptically-evoked Arc expression for at least one month.Importantly, however, spontaneous expression of Arc was detected in BrdU-labeled cells and strongly associated with the survival and maturation of NeuN-positive DGCs.These results suggest an unexpected early role for Arc in adult-born DGCs, distinct from its functions in LTP, LTD, and homeostatic synaptic plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedicine and Bergen Mental Health Research Center, University of Bergen, Bergen, Norway.

ABSTRACT
Progenitor cells in the adult dentate gyrus provide a constant supply of neuronal precursors, yet only a small fraction of these cells survive and develop into mature dentate granule cells (DGCs). A major challenge of current research is thus to understand the stringent selection process that governs the maturation and functional integration of adult-born DGCs. In mature DGCs, high-frequency stimulation (HFS) of the perforant path input elicits robust expression of the immediate early gene Arc/Arg3.1, trafficking of its mRNA to dendrites, and local synthesis of the protein necessary for consolidation of long-term potentiation (LTP). Given the synaptic commitment inherent in LTP consolidation, we considered that HFS-evoked expression of Arc could be used to timemap the functional integration of newborn DGCs. Dividing cells were birthmarked by BrdU-labeling at 1, 7, 14, 21, or 28 days prior to induction of LTP and expression of Arc was examined by confocal microscopy. Contrary to expectation, LTP did not induce Arc expression in newborn cells at any age, suggesting they might be refractory to synaptically-evoked Arc expression for at least one month. Importantly, however, spontaneous expression of Arc was detected in BrdU-labeled cells and strongly associated with the survival and maturation of NeuN-positive DGCs. Moreover, Arc expression at the earliest ages (1 and 7 days), clearly precedes the formation of glutamatergic synapses on new neurons. These results suggest an unexpected early role for Arc in adult-born DGCs, distinct from its functions in LTP, LTD, and homeostatic synaptic plasticity.

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Total BrdU-labeled cells in the dentate gyrus.a, Representative photomicrographs depicting the time course of immunohistochemical BrdU labelling of new DGCs across the age groups. b, Confocal image illustrating immunofluorescent multi-labeling of BrdU-NeuN-GFAP-Dapi taken from an animal of the 1d group. Observations reveal that BrdU cells (green) are located primarily along the SGZ. While initially negative for NeuN expression at 1 day the majority of new cells become neuronal by 28 days (BrdU-NeuN = 83.9%) c, Graph illustrating the average total number of BrdU-labeled cells in the hippocampal granule cell layer (GCL), subgranular zone (SGZ) and hilus per group (n = 8) ±SEM. d, The total number of BrdU-labeled cells in SGZ and GCL depicted as a percentage of the total number of new cells in both regions. The *, #, $, + symbols represents significant effects compared to day 1, 7, 14, 21 respectively. One, two or three symbols represent p<0.05, p<0.005, p<0.0005 respectively.
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pone-0004885-g004: Total BrdU-labeled cells in the dentate gyrus.a, Representative photomicrographs depicting the time course of immunohistochemical BrdU labelling of new DGCs across the age groups. b, Confocal image illustrating immunofluorescent multi-labeling of BrdU-NeuN-GFAP-Dapi taken from an animal of the 1d group. Observations reveal that BrdU cells (green) are located primarily along the SGZ. While initially negative for NeuN expression at 1 day the majority of new cells become neuronal by 28 days (BrdU-NeuN = 83.9%) c, Graph illustrating the average total number of BrdU-labeled cells in the hippocampal granule cell layer (GCL), subgranular zone (SGZ) and hilus per group (n = 8) ±SEM. d, The total number of BrdU-labeled cells in SGZ and GCL depicted as a percentage of the total number of new cells in both regions. The *, #, $, + symbols represents significant effects compared to day 1, 7, 14, 21 respectively. One, two or three symbols represent p<0.05, p<0.005, p<0.0005 respectively.

Mentions: Peroxidase BrdU labeling was performed as previously described [3], [27]. In short, BrdU-labeling requires the following pretreatment steps: DNA denaturation (50% formamide/2×SSC (pH 7.0), 65°C, 120 min), and acidification (2 M HCl, 30 min). Primary antibody was a monoclonal rat anti-BrdU (Oxford Biotechnology, OBT0030CX; 1∶800 dilution in NaPBS 0.02 M, pH 7.4) while secondary antibody was a biotin-SP-conjugated donkey-anti-rat (Jackson ImmunoResearch Laboratories, Inc., West Grove, PA, USA; 1∶400 dilution in NaPBS 0.02 M, pH 7.4). Sections were subsequently incubated with ABC (Vector ABC kit, Vector Laboratories, Burlingame, CA, USA) and after another wash, reaction products were visualized by adding diaminobenzidine as chromogen and 1% H2O2 for 15 min (Arc) or 30 min (BrdU). Finally, sections were washed, mounted on slides, dehydrated and coverslipped with DPX (Fig. 4a).


Selective survival and maturation of adult-born dentate granule cells expressing the immediate early gene Arc/Arg3.1.

Kuipers SD, Tiron A, Soule J, Messaoudi E, Trentani A, Bramham CR - PLoS ONE (2009)

Total BrdU-labeled cells in the dentate gyrus.a, Representative photomicrographs depicting the time course of immunohistochemical BrdU labelling of new DGCs across the age groups. b, Confocal image illustrating immunofluorescent multi-labeling of BrdU-NeuN-GFAP-Dapi taken from an animal of the 1d group. Observations reveal that BrdU cells (green) are located primarily along the SGZ. While initially negative for NeuN expression at 1 day the majority of new cells become neuronal by 28 days (BrdU-NeuN = 83.9%) c, Graph illustrating the average total number of BrdU-labeled cells in the hippocampal granule cell layer (GCL), subgranular zone (SGZ) and hilus per group (n = 8) ±SEM. d, The total number of BrdU-labeled cells in SGZ and GCL depicted as a percentage of the total number of new cells in both regions. The *, #, $, + symbols represents significant effects compared to day 1, 7, 14, 21 respectively. One, two or three symbols represent p<0.05, p<0.005, p<0.0005 respectively.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2654102&req=5

pone-0004885-g004: Total BrdU-labeled cells in the dentate gyrus.a, Representative photomicrographs depicting the time course of immunohistochemical BrdU labelling of new DGCs across the age groups. b, Confocal image illustrating immunofluorescent multi-labeling of BrdU-NeuN-GFAP-Dapi taken from an animal of the 1d group. Observations reveal that BrdU cells (green) are located primarily along the SGZ. While initially negative for NeuN expression at 1 day the majority of new cells become neuronal by 28 days (BrdU-NeuN = 83.9%) c, Graph illustrating the average total number of BrdU-labeled cells in the hippocampal granule cell layer (GCL), subgranular zone (SGZ) and hilus per group (n = 8) ±SEM. d, The total number of BrdU-labeled cells in SGZ and GCL depicted as a percentage of the total number of new cells in both regions. The *, #, $, + symbols represents significant effects compared to day 1, 7, 14, 21 respectively. One, two or three symbols represent p<0.05, p<0.005, p<0.0005 respectively.
Mentions: Peroxidase BrdU labeling was performed as previously described [3], [27]. In short, BrdU-labeling requires the following pretreatment steps: DNA denaturation (50% formamide/2×SSC (pH 7.0), 65°C, 120 min), and acidification (2 M HCl, 30 min). Primary antibody was a monoclonal rat anti-BrdU (Oxford Biotechnology, OBT0030CX; 1∶800 dilution in NaPBS 0.02 M, pH 7.4) while secondary antibody was a biotin-SP-conjugated donkey-anti-rat (Jackson ImmunoResearch Laboratories, Inc., West Grove, PA, USA; 1∶400 dilution in NaPBS 0.02 M, pH 7.4). Sections were subsequently incubated with ABC (Vector ABC kit, Vector Laboratories, Burlingame, CA, USA) and after another wash, reaction products were visualized by adding diaminobenzidine as chromogen and 1% H2O2 for 15 min (Arc) or 30 min (BrdU). Finally, sections were washed, mounted on slides, dehydrated and coverslipped with DPX (Fig. 4a).

Bottom Line: Contrary to expectation, LTP did not induce Arc expression in newborn cells at any age, suggesting they might be refractory to synaptically-evoked Arc expression for at least one month.Importantly, however, spontaneous expression of Arc was detected in BrdU-labeled cells and strongly associated with the survival and maturation of NeuN-positive DGCs.These results suggest an unexpected early role for Arc in adult-born DGCs, distinct from its functions in LTP, LTD, and homeostatic synaptic plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedicine and Bergen Mental Health Research Center, University of Bergen, Bergen, Norway.

ABSTRACT
Progenitor cells in the adult dentate gyrus provide a constant supply of neuronal precursors, yet only a small fraction of these cells survive and develop into mature dentate granule cells (DGCs). A major challenge of current research is thus to understand the stringent selection process that governs the maturation and functional integration of adult-born DGCs. In mature DGCs, high-frequency stimulation (HFS) of the perforant path input elicits robust expression of the immediate early gene Arc/Arg3.1, trafficking of its mRNA to dendrites, and local synthesis of the protein necessary for consolidation of long-term potentiation (LTP). Given the synaptic commitment inherent in LTP consolidation, we considered that HFS-evoked expression of Arc could be used to timemap the functional integration of newborn DGCs. Dividing cells were birthmarked by BrdU-labeling at 1, 7, 14, 21, or 28 days prior to induction of LTP and expression of Arc was examined by confocal microscopy. Contrary to expectation, LTP did not induce Arc expression in newborn cells at any age, suggesting they might be refractory to synaptically-evoked Arc expression for at least one month. Importantly, however, spontaneous expression of Arc was detected in BrdU-labeled cells and strongly associated with the survival and maturation of NeuN-positive DGCs. Moreover, Arc expression at the earliest ages (1 and 7 days), clearly precedes the formation of glutamatergic synapses on new neurons. These results suggest an unexpected early role for Arc in adult-born DGCs, distinct from its functions in LTP, LTD, and homeostatic synaptic plasticity.

Show MeSH
Related in: MedlinePlus