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Essential roles of leucine-rich glioma inactivated 1 in the development of embryonic and postnatal cerebellum.

Xie YJ, Zhou L, Jiang N, Zhang N, Zou N, Zhou L, Wang Y, Cowell JK, Shen Y - Sci Rep (2015)

Bottom Line: The function of LGI1 in CNS development remains undefined.BrdU staining showed an inhibited proliferation of CGPs in KO embryos, which might be explained by the reduced Sonic hedgehog in embryos.Together, our results demonstrate that LGI1 is an essential player in the cerebellar development.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.

ABSTRACT
Leucine-rich glioma inactivated 1 (LGI1) is a secreted protein that interacts with ADAM transmembrane proteins, and its mutations are linked to human epilepsy. The function of LGI1 in CNS development remains undefined. Here, we report novel functions of LGI1 in the generation of cerebellar granule precursors (CGPs) and differentiation of radial glial cells (RGCs) in the cerebellum. A reduction in external granule layer thickness and defects in foliation were seen in embryonic and new-born LGI1 knockout (KO) mice. BrdU staining showed an inhibited proliferation of CGPs in KO embryos, which might be explained by the reduced Sonic hedgehog in embryos. In addition, the differentiation of RGCs into Bergmann glias was suppressed in KO mice. Enhanced Jagged1-Notch1 signaling in KO mice via reduced β-secretase proteolysis suggests that altered phenotype of RGCs is due to abnormal Notch1 signaling. Together, our results demonstrate that LGI1 is an essential player in the cerebellar development.

No MeSH data available.


Related in: MedlinePlus

Loss of LGI1 results in reduced differentiation of RGCs.(a) Mid-sagittal sections of P1 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the interior area and EGL respectively, showing that BLBP expression was increased whereas GFAP expression was reduced in the KO mice (n = 5 pairs). Scale bars: 50 μm. (b) Mid-sagittal sections of P7 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the white matter area and BG cell bodies, respectively (n = 5 pairs). Scale bars: 50 μm. (c) Total expression of BLBP and GFAP was measured in WT and KO littermates at P1 and P7 using GAPDH as the internal control. Lower panel: the percentage changes of BLBP and GFAP signal intensity (KO vs WT) were 157.5 ± 21.2% (P1, BLBP; p = 0.044), 195.8 ± 29.8% (P7, BLBP; p = 0.028), 47.6 ± 12.2% (P1, GFAP; p = 0.0087), and 42.7 ± 10.8% (P7, GFAP; p = 0.0075). Experiments were performed on 6 pairs of littermates. Statistical analysis was done by one-sided Student's t-test. ** p < 0.01. * p < 0.05. (d) Dentate gyrus of P14 hippocampus stained for BLBP. Arrowheads indicate the fluorescence intensity of BLBP in WT and KO mice (n = 3 pairs). Scale bars: 50 μm.
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f5: Loss of LGI1 results in reduced differentiation of RGCs.(a) Mid-sagittal sections of P1 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the interior area and EGL respectively, showing that BLBP expression was increased whereas GFAP expression was reduced in the KO mice (n = 5 pairs). Scale bars: 50 μm. (b) Mid-sagittal sections of P7 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the white matter area and BG cell bodies, respectively (n = 5 pairs). Scale bars: 50 μm. (c) Total expression of BLBP and GFAP was measured in WT and KO littermates at P1 and P7 using GAPDH as the internal control. Lower panel: the percentage changes of BLBP and GFAP signal intensity (KO vs WT) were 157.5 ± 21.2% (P1, BLBP; p = 0.044), 195.8 ± 29.8% (P7, BLBP; p = 0.028), 47.6 ± 12.2% (P1, GFAP; p = 0.0087), and 42.7 ± 10.8% (P7, GFAP; p = 0.0075). Experiments were performed on 6 pairs of littermates. Statistical analysis was done by one-sided Student's t-test. ** p < 0.01. * p < 0.05. (d) Dentate gyrus of P14 hippocampus stained for BLBP. Arrowheads indicate the fluorescence intensity of BLBP in WT and KO mice (n = 3 pairs). Scale bars: 50 μm.

Mentions: In the cerebellum, RGCs provide a scaffold for the migration of granule cells and are essential for organizing the laminated structure31. The disrupted morphogenesis in KO mice led us to determine whether the phenotype of RGCs was affected. Immunostaining for brain lipid-binding protein (BLBP), a specific marker that labels RGCs in the postnatal cerebellum3233, showed that RGC fibers were oriented parallel to each other and perpendicular to the outer surface (Fig. 5a), particularly near the anchoring center where CGPs accumulate (Fig. 5a, yellow arrowheads). Unexpectedly, a remarkable increase, rather than a decrease, in the BLBP signal was observed in both the EGL and the IGL of the KO cerebellum (Fig. 5a). At P7, the augmented BLBP staining remained extensive mainly in the cell bodies and white matter area (Fig. 5b). The orientation of RGC fibers was also normal in the KO cerebellum (Fig. 5b).


Essential roles of leucine-rich glioma inactivated 1 in the development of embryonic and postnatal cerebellum.

Xie YJ, Zhou L, Jiang N, Zhang N, Zou N, Zhou L, Wang Y, Cowell JK, Shen Y - Sci Rep (2015)

Loss of LGI1 results in reduced differentiation of RGCs.(a) Mid-sagittal sections of P1 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the interior area and EGL respectively, showing that BLBP expression was increased whereas GFAP expression was reduced in the KO mice (n = 5 pairs). Scale bars: 50 μm. (b) Mid-sagittal sections of P7 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the white matter area and BG cell bodies, respectively (n = 5 pairs). Scale bars: 50 μm. (c) Total expression of BLBP and GFAP was measured in WT and KO littermates at P1 and P7 using GAPDH as the internal control. Lower panel: the percentage changes of BLBP and GFAP signal intensity (KO vs WT) were 157.5 ± 21.2% (P1, BLBP; p = 0.044), 195.8 ± 29.8% (P7, BLBP; p = 0.028), 47.6 ± 12.2% (P1, GFAP; p = 0.0087), and 42.7 ± 10.8% (P7, GFAP; p = 0.0075). Experiments were performed on 6 pairs of littermates. Statistical analysis was done by one-sided Student's t-test. ** p < 0.01. * p < 0.05. (d) Dentate gyrus of P14 hippocampus stained for BLBP. Arrowheads indicate the fluorescence intensity of BLBP in WT and KO mice (n = 3 pairs). Scale bars: 50 μm.
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Related In: Results  -  Collection

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f5: Loss of LGI1 results in reduced differentiation of RGCs.(a) Mid-sagittal sections of P1 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the interior area and EGL respectively, showing that BLBP expression was increased whereas GFAP expression was reduced in the KO mice (n = 5 pairs). Scale bars: 50 μm. (b) Mid-sagittal sections of P7 cerebella stained for BLBP and GFAP. White and yellow arrowheads indicate the fluorescence in the white matter area and BG cell bodies, respectively (n = 5 pairs). Scale bars: 50 μm. (c) Total expression of BLBP and GFAP was measured in WT and KO littermates at P1 and P7 using GAPDH as the internal control. Lower panel: the percentage changes of BLBP and GFAP signal intensity (KO vs WT) were 157.5 ± 21.2% (P1, BLBP; p = 0.044), 195.8 ± 29.8% (P7, BLBP; p = 0.028), 47.6 ± 12.2% (P1, GFAP; p = 0.0087), and 42.7 ± 10.8% (P7, GFAP; p = 0.0075). Experiments were performed on 6 pairs of littermates. Statistical analysis was done by one-sided Student's t-test. ** p < 0.01. * p < 0.05. (d) Dentate gyrus of P14 hippocampus stained for BLBP. Arrowheads indicate the fluorescence intensity of BLBP in WT and KO mice (n = 3 pairs). Scale bars: 50 μm.
Mentions: In the cerebellum, RGCs provide a scaffold for the migration of granule cells and are essential for organizing the laminated structure31. The disrupted morphogenesis in KO mice led us to determine whether the phenotype of RGCs was affected. Immunostaining for brain lipid-binding protein (BLBP), a specific marker that labels RGCs in the postnatal cerebellum3233, showed that RGC fibers were oriented parallel to each other and perpendicular to the outer surface (Fig. 5a), particularly near the anchoring center where CGPs accumulate (Fig. 5a, yellow arrowheads). Unexpectedly, a remarkable increase, rather than a decrease, in the BLBP signal was observed in both the EGL and the IGL of the KO cerebellum (Fig. 5a). At P7, the augmented BLBP staining remained extensive mainly in the cell bodies and white matter area (Fig. 5b). The orientation of RGC fibers was also normal in the KO cerebellum (Fig. 5b).

Bottom Line: The function of LGI1 in CNS development remains undefined.BrdU staining showed an inhibited proliferation of CGPs in KO embryos, which might be explained by the reduced Sonic hedgehog in embryos.Together, our results demonstrate that LGI1 is an essential player in the cerebellar development.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.

ABSTRACT
Leucine-rich glioma inactivated 1 (LGI1) is a secreted protein that interacts with ADAM transmembrane proteins, and its mutations are linked to human epilepsy. The function of LGI1 in CNS development remains undefined. Here, we report novel functions of LGI1 in the generation of cerebellar granule precursors (CGPs) and differentiation of radial glial cells (RGCs) in the cerebellum. A reduction in external granule layer thickness and defects in foliation were seen in embryonic and new-born LGI1 knockout (KO) mice. BrdU staining showed an inhibited proliferation of CGPs in KO embryos, which might be explained by the reduced Sonic hedgehog in embryos. In addition, the differentiation of RGCs into Bergmann glias was suppressed in KO mice. Enhanced Jagged1-Notch1 signaling in KO mice via reduced β-secretase proteolysis suggests that altered phenotype of RGCs is due to abnormal Notch1 signaling. Together, our results demonstrate that LGI1 is an essential player in the cerebellar development.

No MeSH data available.


Related in: MedlinePlus