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Kim T, Park H, Tanaka-Yamamoto K, Yamamoto Y. Developmental timing-dependent organization of synaptic connections between mossy fibers and granule cells in the cerebellum. Commun Biol 2023; 6:446. [PMID: 37095324 PMCID: PMC10125988 DOI: 10.1038/s42003-023-04825-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 04/07/2023] [Indexed: 04/26/2023] Open
Abstract
The long-standing hypothesis that synapses between mossy fibers (MFs) and cerebellar granule cells (GCs) are organized according to the origins of MFs and locations of GC axons, parallel fibers (PFs), is supported by recent findings. However, the mechanisms of such organized synaptic connections remain unknown. Here, using our technique that enabled PF location-dependent labeling of GCs in mice, we confirmed that synaptic connections of GCs with specific MFs originating from the pontine nucleus (PN-MFs) and dorsal column nuclei (DCoN-MFs) were gently but differentially organized according to their PF locations. We then found that overall MF-GC synaptic connectivity was biased in a way that dendrites of GCs having nearby PFs tended to connect with the same MF terminals, implying that the MF origin- and PF location-dependent organization is associated with the overall biased MF-GC synaptic connectivity. Furthermore, the development of PN-MFs preceded that of DCoN-MFs, which matches the developmental sequence of GCs that preferentially connect with each type of these MFs. Thus, our results revealed that overall MF-GC synaptic connectivity is biased in terms of PF locations, and suggested that such connectivity is likely the result of synaptic formation between developmental timing-matched partners.
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Affiliation(s)
- Taegon Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Heeyoun Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Keiko Tanaka-Yamamoto
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
| | - Yukio Yamamoto
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
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Dey MR, Reddy K, Yoshida H, Nishiyama N, Zemelman BV, Nishiyama H. Granule Cells Constitute One of the Major Neuronal Subtypes in the Molecular Layer of the Posterior Cerebellum. eNeuro 2022; 9:ENEURO.0289-21.2022. [PMID: 35584915 PMCID: PMC9172288 DOI: 10.1523/eneuro.0289-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 03/07/2022] [Accepted: 04/18/2022] [Indexed: 12/02/2022] Open
Abstract
The migration of neurons from their birthplace to their correct destination is one of the most crucial steps in brain development. Incomplete or incorrect migration yields ectopic neurons, which cause neurologic deficits or are negligible at best. However, the granule cells (GCs) in the cerebellar cortex may challenge this traditional view of ectopic neurons. When animals are born, GCs proliferate near the pia mater and then migrate down to the GC layer located deep in the cerebellar cortex. However, some GC-like cells stay in the molecular layer, a layer between the pia mater and GC layer, even in normal adult animals. These cells were named ectopic GCs nearly 50 years ago, but their abundance and functional properties remain unclear. Here, we have examined GCs in the molecular layer (mGCs) with a specific marker for mature GCs and transgenic mice in which GCs are sparsely labeled with a fluorescent protein. Contrary to the previous assumption that mGCs are a minor neuronal population, we have found that mGCs are as prevalent as stellate or basket cells in the posterior cerebellum. They are produced during a similar period as regular GCs (rGCs), and in vivo time-lapse imaging has revealed that mGCs are stably present in the molecular layer. Whole-cell patch-clamp recordings have shown that mGCs discharge action potentials similarly to rGCs. Since axonal inputs differ between the molecular layer and GC layer, mGCs might be incorporated in different micro-circuits from rGCs and have a unique functional role in the cerebellum.
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Affiliation(s)
- Moushumi R Dey
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Kirthan Reddy
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Hiroichi Yoshida
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Naoko Nishiyama
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Boris V Zemelman
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Hiroshi Nishiyama
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
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Brandalise F, Ratto D, Leone R, Olivero F, Roda E, Locatelli CA, Grazia Bottone M, Rossi P. Deeper and Deeper on the Role of BK and Kir4.1 Channels in Glioblastoma Invasiveness: A Novel Summative Mechanism? Front Neurosci 2020; 14:595664. [PMID: 33328867 PMCID: PMC7734145 DOI: 10.3389/fnins.2020.595664] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
In the last decades, increasing evidence has revealed that a large number of channel protein and ion pumps exhibit impaired expression in cancers. This dysregulation is responsible for high proliferative rates as well as migration and invasiveness, reflected in the recently coined term oncochannelopathies. In glioblastoma (GBM), the most invasive and aggressive primary brain tumor, GBM cells modify their ionic equilibrium in order to change their volume as a necessary step prior to migration. This mechanism involves increased expression of BK channels and downregulation of the normally widespread Kir4.1 channels, as noted in GBM biopsies from patients. Despite a large body of work implicating BK channels in migration in response to an artificial intracellular calcium rise, little is known about how this channel acts in GBM cells at resting membrane potential (RMP), as compared to other channels that are constitutively open, such as Kir4.1. In this review we propose that a residual fraction of functionally active Kir4.1 channels mediates a small, but continuous, efflux of potassium at the more depolarized RMP of GBM cells. In addition, coinciding with transient membrane deformation and the intracellular rise in calcium concentration, brief activity of BK channels can induce massive and rapid cytosolic water loss that reduces cell volume (cell shrinkage), a necessary step for migration within the brain parenchyma.
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Affiliation(s)
- Federico Brandalise
- Department of Fundamental Neurosciences (NEUFO), University of Geneva, Geneva, Switzerland
| | - Daniela Ratto
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
| | - Roberta Leone
- Department of Fundamental Neurosciences (NEUFO), University of Geneva, Geneva, Switzerland
| | - Federico Olivero
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
| | - Elisa Roda
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy.,Pavia Poison Centre, National Toxicology Information Centre, Laboratory of Clinical & Experimental Toxicology, Toxicology Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Carlo Alessandro Locatelli
- Pavia Poison Centre, National Toxicology Information Centre, Laboratory of Clinical & Experimental Toxicology, Toxicology Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Maria Grazia Bottone
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
| | - Paola Rossi
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
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Ratto D, Ferrari B, Roda E, Brandalise F, Siciliani S, De Luca F, Priori EC, Di Iorio C, Cobelli F, Veneroni P, Bottone MG, Rossi P. Squaring the Circle: A New Study of Inward and Outward-Rectifying Potassium Currents in U251 GBM Cells. Cell Mol Neurobiol 2019; 40:813-828. [PMID: 31845161 DOI: 10.1007/s10571-019-00776-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 12/09/2019] [Indexed: 12/18/2022]
Abstract
In the present study, the functional role of the inwardly rectifying K+ channel, Kir4.1, and large-conductance Ca2+-activated K+ (BK) channel during cell migration in U251 cell line was investigated. We focused on polarised cells which are positive for the active-Cdc42 migration marker. The perforated patch technique was used to avoid intracellular dialysis and to maintain physiological changes in intracellular calcium. Wound healing was employed to assay migration after 24 h. Polarised cells recorded displayed different hallmarks of undifferentiated glial cells: depolarised resting membrane potential and high membrane resistance. Cells recorded outside wounded area did not display either constitutive inward or outward rectification. After migration, U251 cells were characterised by a constitutively smaller Kir4.1 and larger BK currents with a linearly related amplitude. Menthol modulation increased both currents in a linearly dependent manner, indicating a common mechanism triggered by activation of transient receptor potential melastatin 8 (TRPM8), a Ca2+-permeable non-selective cation channel. We hypothesised that both migration and menthol modulation would share an increase of intracellular calcium triggering the increase in Kir4.1 and BK channels. Immunocytochemistry demonstrated the cytoplasmic expression of both Kir4.1 and BK channels and a mislocation in the nucleus under basal conditions. Before and after migration, polarised cells increased the expression of Kir4.1 and BK channels both in the cytoplasm and nucleus. TEM ultrastructural analysis displayed a different nuclear distribution of Kir4.1 and BK channels. In the present study, the physiological role of Kir4.1 and BK currents at membrane potential, their involvement in migration, and the functional role of nuclear channels were discussed.
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Affiliation(s)
- Daniela Ratto
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Beatrice Ferrari
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Elisa Roda
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
- Toxicology Unit, Laboratory of Clinical & Experimental Toxicology, Pavia Poison Centre, National Toxicology Information Centre, ICS Maugeri SpA, IRCCS Pavia, 27100, Pavia, Italy
| | - Federico Brandalise
- Department of Fundamental Neurosciences (NEUFO), University of Geneva, 1211, Geneva, Switzerland
| | - Stella Siciliani
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Fabrizio De Luca
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Erica Cecilia Priori
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Carmine Di Iorio
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Filippo Cobelli
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Paola Veneroni
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Maria Grazia Bottone
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy
| | - Paola Rossi
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, 27100, Pavia, Italy.
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