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Expression of TrkC receptors in the developing brain of the Monodelphis opossum and its effect on the development of cortical cells.

Bartkowska K, Gajerska M, Turlejski K, Djavadian RL - PLoS ONE (2013)

Bottom Line: We found that in different neocortical areas located both at the rostral and caudal regions of the cortex, up to 98% of BrdU-labeled cells forming cortical layers (II-VI) had prominently expressed TrkC.The shRNAs were individually tested in transfected cortical progenitor cells grown on culture plates for 2 days.The effects of the shRNA-TrkC constructs were similar: blockade of TrkC receptors decreased the number of Ki67-positive and apoptotic cells, and it did not change the number of TUJ-positive neurons in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland.

ABSTRACT
In this study, we investigated the distribution, localization and several various functions of TrkC receptors during development of the Monodelphisopossum brain. Western blotting analysis showed that two different forms of the TrkC receptor, the full-length receptor and one of its truncated forms, are abundantly expressed in the opossum brain. The expression of TrkC receptors was barely detected in the brain of newborn opossums. At postnatal day (P) 3, the expression of full-length TrkC remained at low levels, while moderate expression of the TrkC truncated form was detected. The expression levels of both forms of this protein gradually increased throughout development, peaking at P35. We found that in different neocortical areas located both at the rostral and caudal regions of the cortex, up to 98% of BrdU-labeled cells forming cortical layers (II-VI) had prominently expressed TrkC. To assess which developmental processes of cortical cells are regulated by TrkC receptors, three different shRNAs were constructed. The shRNAs were individually tested in transfected cortical progenitor cells grown on culture plates for 2 days. The effects of the shRNA-TrkC constructs were similar: blockade of TrkC receptors decreased the number of Ki67-positive and apoptotic cells, and it did not change the number of TUJ-positive neurons in vitro. Thus, the lack of TrkC receptors in cultured progenitor cells provided insight on the potential role of these receptors in the regulation of proliferation and cell survival but not in the differentiation of cortical cells.

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Expression of the full-length and truncated TrkC receptors in different brain structures in the opossum.A - Western blotting analysis was performed in 6 different regions of the brains at P35, P60 and adults: OB –olfactory bulb, CTX –cerebral cortex, HIP –hippocampus, TH –thalamus, CER –cerebellum, and BRST – brainstem structures. GAPDH was used as a loading control. The arrows indicate the positions of the full-length (TrkC-F) and truncated (TrkC-T) TrkC receptors. B – graphs showing the amount of both forms of TrkC receptors in the brain structures. Error bars indicate ± S.E.M.
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pone-0074346-g002: Expression of the full-length and truncated TrkC receptors in different brain structures in the opossum.A - Western blotting analysis was performed in 6 different regions of the brains at P35, P60 and adults: OB –olfactory bulb, CTX –cerebral cortex, HIP –hippocampus, TH –thalamus, CER –cerebellum, and BRST – brainstem structures. GAPDH was used as a loading control. The arrows indicate the positions of the full-length (TrkC-F) and truncated (TrkC-T) TrkC receptors. B – graphs showing the amount of both forms of TrkC receptors in the brain structures. Error bars indicate ± S.E.M.

Mentions: To study the distribution of TrkC receptors various brain regions were isolated using dissection. This method was performed over three stages of development: P35, which corresponded to the time of eye opening, P60, a period when the opossums are weaned, and P400, when opossums are fully adult. At early ages, the opossum brains were too small to collect some of the brain regions. Strong expression of both full-length and truncated forms of TrkC was observed in the hippocampus, cerebellum and cerebral cortex. However, slightly lower expression was found in the thalamus and olfactory bulb at P60 and in adult opossums (Figure 2 A). Both full-length and truncated TrkC were detected at very low levels in the brainstem structures at P60 and in adult animals (Figure 2 B). We observed that the level of TrkC expression was 6-7 times higher in the adult cerebral cortex compared to other brainstem structures (p<0.006). Interestingly, in all of the examined structures, expression of the truncated form of the TrkC receptor was higher compared to the expression of its full-length form, specifically in the adult cerebral cortex (p<0.02).


Expression of TrkC receptors in the developing brain of the Monodelphis opossum and its effect on the development of cortical cells.

Bartkowska K, Gajerska M, Turlejski K, Djavadian RL - PLoS ONE (2013)

Expression of the full-length and truncated TrkC receptors in different brain structures in the opossum.A - Western blotting analysis was performed in 6 different regions of the brains at P35, P60 and adults: OB –olfactory bulb, CTX –cerebral cortex, HIP –hippocampus, TH –thalamus, CER –cerebellum, and BRST – brainstem structures. GAPDH was used as a loading control. The arrows indicate the positions of the full-length (TrkC-F) and truncated (TrkC-T) TrkC receptors. B – graphs showing the amount of both forms of TrkC receptors in the brain structures. Error bars indicate ± S.E.M.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3760877&req=5

pone-0074346-g002: Expression of the full-length and truncated TrkC receptors in different brain structures in the opossum.A - Western blotting analysis was performed in 6 different regions of the brains at P35, P60 and adults: OB –olfactory bulb, CTX –cerebral cortex, HIP –hippocampus, TH –thalamus, CER –cerebellum, and BRST – brainstem structures. GAPDH was used as a loading control. The arrows indicate the positions of the full-length (TrkC-F) and truncated (TrkC-T) TrkC receptors. B – graphs showing the amount of both forms of TrkC receptors in the brain structures. Error bars indicate ± S.E.M.
Mentions: To study the distribution of TrkC receptors various brain regions were isolated using dissection. This method was performed over three stages of development: P35, which corresponded to the time of eye opening, P60, a period when the opossums are weaned, and P400, when opossums are fully adult. At early ages, the opossum brains were too small to collect some of the brain regions. Strong expression of both full-length and truncated forms of TrkC was observed in the hippocampus, cerebellum and cerebral cortex. However, slightly lower expression was found in the thalamus and olfactory bulb at P60 and in adult opossums (Figure 2 A). Both full-length and truncated TrkC were detected at very low levels in the brainstem structures at P60 and in adult animals (Figure 2 B). We observed that the level of TrkC expression was 6-7 times higher in the adult cerebral cortex compared to other brainstem structures (p<0.006). Interestingly, in all of the examined structures, expression of the truncated form of the TrkC receptor was higher compared to the expression of its full-length form, specifically in the adult cerebral cortex (p<0.02).

Bottom Line: We found that in different neocortical areas located both at the rostral and caudal regions of the cortex, up to 98% of BrdU-labeled cells forming cortical layers (II-VI) had prominently expressed TrkC.The shRNAs were individually tested in transfected cortical progenitor cells grown on culture plates for 2 days.The effects of the shRNA-TrkC constructs were similar: blockade of TrkC receptors decreased the number of Ki67-positive and apoptotic cells, and it did not change the number of TUJ-positive neurons in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland.

ABSTRACT
In this study, we investigated the distribution, localization and several various functions of TrkC receptors during development of the Monodelphisopossum brain. Western blotting analysis showed that two different forms of the TrkC receptor, the full-length receptor and one of its truncated forms, are abundantly expressed in the opossum brain. The expression of TrkC receptors was barely detected in the brain of newborn opossums. At postnatal day (P) 3, the expression of full-length TrkC remained at low levels, while moderate expression of the TrkC truncated form was detected. The expression levels of both forms of this protein gradually increased throughout development, peaking at P35. We found that in different neocortical areas located both at the rostral and caudal regions of the cortex, up to 98% of BrdU-labeled cells forming cortical layers (II-VI) had prominently expressed TrkC. To assess which developmental processes of cortical cells are regulated by TrkC receptors, three different shRNAs were constructed. The shRNAs were individually tested in transfected cortical progenitor cells grown on culture plates for 2 days. The effects of the shRNA-TrkC constructs were similar: blockade of TrkC receptors decreased the number of Ki67-positive and apoptotic cells, and it did not change the number of TUJ-positive neurons in vitro. Thus, the lack of TrkC receptors in cultured progenitor cells provided insight on the potential role of these receptors in the regulation of proliferation and cell survival but not in the differentiation of cortical cells.

Show MeSH
Related in: MedlinePlus