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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

Abnormal foliation in the KO cerebellum.(a) Mid-sagittal sections of E15.5, P0, P7, and P14 cerebella derived from WT and KO littermates were stained with DAPI. Higher magnifications show segments of the EGL (boxes in E15.5 panels). The dashed lines show the interior edge of EGL. Note that the EGL thickness was reduced in KO cerebella (white arrowheads). At P0, the WT cerebellum had developed 7 lobes, but the KO cerebellum displayed only 5 (white arrowheads). No folia defects were found in P7 and P14 KO littermates. Roman numerals denote cerebellar lobules for both WT and KO cerebella. n = 7 pairs for P0, P7, or P14. Scale bars: 200 μm. (a') The thickness of the EGL at E15.5 was 30.1 ± 1.0 μm (WT) or 20.0 ± 0.8 μm (KO). n = 6 pairs, *** p < 0.001 (p = 0.0003, two-sided Student's t-test). (b) H&E staining of mid-sagittal sections from P0, P7, and P14 cerebella. KO cerebella (P0) showed marked agenesis of foliation (arrowheads), which was mostly corrected in P7 and P14 cerebella. Missing fissures were sometimes observed in P7 cerebella (arrowhead in the middle panel). n = 5 pairs for each age. Scale bars: 200 μm. (c) P0 cerebella stained with DAPI and with laminin-1 (laminin). While the foliation deficit was evident in the KO mice (arrowheads in left panels), laminin-1 staining was intact and continuous along the cerebellar surface (n = 5 pairs). Scale bars: 200 μm.
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f1: Abnormal foliation in the KO cerebellum.(a) Mid-sagittal sections of E15.5, P0, P7, and P14 cerebella derived from WT and KO littermates were stained with DAPI. Higher magnifications show segments of the EGL (boxes in E15.5 panels). The dashed lines show the interior edge of EGL. Note that the EGL thickness was reduced in KO cerebella (white arrowheads). At P0, the WT cerebellum had developed 7 lobes, but the KO cerebellum displayed only 5 (white arrowheads). No folia defects were found in P7 and P14 KO littermates. Roman numerals denote cerebellar lobules for both WT and KO cerebella. n = 7 pairs for P0, P7, or P14. Scale bars: 200 μm. (a') The thickness of the EGL at E15.5 was 30.1 ± 1.0 μm (WT) or 20.0 ± 0.8 μm (KO). n = 6 pairs, *** p < 0.001 (p = 0.0003, two-sided Student's t-test). (b) H&E staining of mid-sagittal sections from P0, P7, and P14 cerebella. KO cerebella (P0) showed marked agenesis of foliation (arrowheads), which was mostly corrected in P7 and P14 cerebella. Missing fissures were sometimes observed in P7 cerebella (arrowhead in the middle panel). n = 5 pairs for each age. Scale bars: 200 μm. (c) P0 cerebella stained with DAPI and with laminin-1 (laminin). While the foliation deficit was evident in the KO mice (arrowheads in left panels), laminin-1 staining was intact and continuous along the cerebellar surface (n = 5 pairs). Scale bars: 200 μm.

Mentions: The morphogenesis of the KO cerebellum was studied in sagittal sections of the cerebellum at embryonic and postnatal stages. Interestingly, while the cerebellar morphology was grossly normal, we found an apparent reduction of EGL thickness in the E15.5 KO embryos (Fig. 1a-a'). This finding implies that loss of LGI1 affects cerebellar foliation, because cerebellar granule precursors (CGPs) migrate outwardly to form the EGL18, and the expansion of the EGL is necessary for proper foliation1920. Indeed, a prominent foliation defect was found in all new-born KO mice examined. At P0, the WT cerebellum developed elongated fissures and lobules. In contrast, some fissures in the KO cerebellum at the same age were less developed or missing, resulting in only 5 cardinal lobes rather than 7 (Fig. 1a). Moreover, the length of the lobes was generally shorter in the KO embryos (Fig. 1a). Unexpectedly, the folia were grossly normal in P7 and P14 KO pups (Fig. 1a). H&E staining was also used to examine the foliation in P0, P7, and P14 cerebella, and showed that LGI1-KO only affected the foliation at P0, and not at P7 or P14 (Fig. 1b). Together, these results suggested that the Lgi1- mutation retards, but does not prevent, the folia formation in the cerebellum.


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)

Abnormal foliation in the KO cerebellum.(a) Mid-sagittal sections of E15.5, P0, P7, and P14 cerebella derived from WT and KO littermates were stained with DAPI. Higher magnifications show segments of the EGL (boxes in E15.5 panels). The dashed lines show the interior edge of EGL. Note that the EGL thickness was reduced in KO cerebella (white arrowheads). At P0, the WT cerebellum had developed 7 lobes, but the KO cerebellum displayed only 5 (white arrowheads). No folia defects were found in P7 and P14 KO littermates. Roman numerals denote cerebellar lobules for both WT and KO cerebella. n = 7 pairs for P0, P7, or P14. Scale bars: 200 μm. (a') The thickness of the EGL at E15.5 was 30.1 ± 1.0 μm (WT) or 20.0 ± 0.8 μm (KO). n = 6 pairs, *** p < 0.001 (p = 0.0003, two-sided Student's t-test). (b) H&E staining of mid-sagittal sections from P0, P7, and P14 cerebella. KO cerebella (P0) showed marked agenesis of foliation (arrowheads), which was mostly corrected in P7 and P14 cerebella. Missing fissures were sometimes observed in P7 cerebella (arrowhead in the middle panel). n = 5 pairs for each age. Scale bars: 200 μm. (c) P0 cerebella stained with DAPI and with laminin-1 (laminin). While the foliation deficit was evident in the KO mice (arrowheads in left panels), laminin-1 staining was intact and continuous along the cerebellar surface (n = 5 pairs). Scale bars: 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4296302&req=5

f1: Abnormal foliation in the KO cerebellum.(a) Mid-sagittal sections of E15.5, P0, P7, and P14 cerebella derived from WT and KO littermates were stained with DAPI. Higher magnifications show segments of the EGL (boxes in E15.5 panels). The dashed lines show the interior edge of EGL. Note that the EGL thickness was reduced in KO cerebella (white arrowheads). At P0, the WT cerebellum had developed 7 lobes, but the KO cerebellum displayed only 5 (white arrowheads). No folia defects were found in P7 and P14 KO littermates. Roman numerals denote cerebellar lobules for both WT and KO cerebella. n = 7 pairs for P0, P7, or P14. Scale bars: 200 μm. (a') The thickness of the EGL at E15.5 was 30.1 ± 1.0 μm (WT) or 20.0 ± 0.8 μm (KO). n = 6 pairs, *** p < 0.001 (p = 0.0003, two-sided Student's t-test). (b) H&E staining of mid-sagittal sections from P0, P7, and P14 cerebella. KO cerebella (P0) showed marked agenesis of foliation (arrowheads), which was mostly corrected in P7 and P14 cerebella. Missing fissures were sometimes observed in P7 cerebella (arrowhead in the middle panel). n = 5 pairs for each age. Scale bars: 200 μm. (c) P0 cerebella stained with DAPI and with laminin-1 (laminin). While the foliation deficit was evident in the KO mice (arrowheads in left panels), laminin-1 staining was intact and continuous along the cerebellar surface (n = 5 pairs). Scale bars: 200 μm.
Mentions: The morphogenesis of the KO cerebellum was studied in sagittal sections of the cerebellum at embryonic and postnatal stages. Interestingly, while the cerebellar morphology was grossly normal, we found an apparent reduction of EGL thickness in the E15.5 KO embryos (Fig. 1a-a'). This finding implies that loss of LGI1 affects cerebellar foliation, because cerebellar granule precursors (CGPs) migrate outwardly to form the EGL18, and the expansion of the EGL is necessary for proper foliation1920. Indeed, a prominent foliation defect was found in all new-born KO mice examined. At P0, the WT cerebellum developed elongated fissures and lobules. In contrast, some fissures in the KO cerebellum at the same age were less developed or missing, resulting in only 5 cardinal lobes rather than 7 (Fig. 1a). Moreover, the length of the lobes was generally shorter in the KO embryos (Fig. 1a). Unexpectedly, the folia were grossly normal in P7 and P14 KO pups (Fig. 1a). H&E staining was also used to examine the foliation in P0, P7, and P14 cerebella, and showed that LGI1-KO only affected the foliation at P0, and not at P7 or P14 (Fig. 1b). Together, these results suggested that the Lgi1- mutation retards, but does not prevent, the folia formation in the cerebellum.

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