1
|
Abdali SS, Yokoyama T, Nakamuta N, Saino T, Yamamoto Y. Immunohistochemical analysis of glutamatergic and serotonergic signaling pathways in chemosensory cell clusters in the pharynx and larynx of rats. Tissue Cell 2023; 82:102122. [PMID: 37262979 DOI: 10.1016/j.tice.2023.102122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/19/2023] [Accepted: 05/26/2023] [Indexed: 06/03/2023]
Abstract
The present study examined cellular components and the localization of vesicular glutamate transporter (VGLUT) 1 and 2 and serotonin (5-HT) in chemosensory cell clusters in the rat pharynx and larynx. Triple immunolabeling for guanine nucleotide-binding protein G (t), subunit ⍺3 (GNAT3) and nucleoside triphosphate diphosphohydrolase 2 (NTPDase2) with synaptotagmin-1 (Syt1) revealed NTPDase2-immunoreactive type I-like cells in addition to GNAT3-immunoreactive type II-like and Syt1-immunoreactive type III-like cells in pharyngolaryngeal chemosensory cell clusters. Therefore, these clusters appear to comprise similar cell types to those in the lingual taste buds with slight morphological modifications. An immunofluorescence analysis of VGLUT1 or VGLUT2 and GNAT3 with P2X3 purinoceptors revealed that VGLUTs co-localized to P2X3-immunoreactive spherical nerve terminals closely associated with GNAT3-immunoreactive type II-like cells. Moreover, triple immunolabeling for Syt1/synaptosomal-associated protein, 25 kDa (SNAP25) and P2X3 with VGLUT1 or VGLUT2 revealed punctate immunoreactive products for VGLUT1 and VGLUT2 within P2X3-immunoreactive flat axon terminals wrapped around Syt1/SNAP25-immunoreactive type III-like cells. The afferent nerve fibers innervating cell clusters may contain glutamate and release it by exocytosis. On the other hand, immunoreactive products for 5-HT and dopa decarboxylase were detected in Syt1-immunoreactive cells, indicating the release of 5-HT by these cells. The present results suggest that chemosensory cell clusters in the pharynx and larynx may be modulated by intrinsic glutamate and 5-HT.
Collapse
Affiliation(s)
- Sayed Sharif Abdali
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan.
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Tomoyuki Saino
- Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan
| |
Collapse
|
2
|
Casaletto K, Ramos-Miguel A, VandeBunte A, Memel M, Buchman A, Bennett D, Honer W. Late-life physical activity relates to brain tissue synaptic integrity markers in older adults. Alzheimers Dement 2022; 18:2023-2035. [PMID: 34994517 PMCID: PMC9259753 DOI: 10.1002/alz.12530] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/27/2021] [Accepted: 10/14/2021] [Indexed: 01/31/2023]
Abstract
INTRODUCTION Physical activity (PA) is widely recommended for age-related brain health, yet its neurobiology is not well understood. Animal models indicate PA is synaptogenic. We examined the relationship between PA and synaptic integrity markers in older adults. METHODS Four hundred four decedents from the Rush Memory and Aging Project completed annual actigraphy monitoring (Mean visits = 3.5±2.4) and post mortem evaluation. Brain tissue was analyzed for presynaptic proteins (synaptophysin, synaptotagmin-1, vesicle-associated membrane proteins, syntaxin, complexin-I, and complexin-II), and neuropathology. Models examined relationships between late-life PA (averaged across visits), and timing-specific PA (time to autopsy) with synaptic proteins. RESULTS Greater late-life PA associated with higher presynaptic protein levels (0.14 < β < 0.20), except complexin-II (β = 0.08). Relationships were independent of pathology but timing specific; participants who completed actigraphy within 2 years of brain tissue measurements showed largest PA-to-synaptic protein associations (0.32 < β < 0.38). Relationships between PA and presynaptic proteins were comparable across brain regions sampled. DISCUSSION PA associates with synaptic integrity in a regionally global, but time-linked nature in older adults.
Collapse
Affiliation(s)
- Kaitlin Casaletto
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA
| | - Alfredo Ramos-Miguel
- Department of Pharmacology, CIBERSAM, University of the Basque Country (EHU/UPV) and Centro de Investigación Biomédica en Red de Salud Mental, Leioa, Spain
| | - Anna VandeBunte
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA
| | - Molly Memel
- San Francisco VA Medical Center, San Francisco California, USA
| | - Aron Buchman
- Rush Alzheimer's Disease Center, Rush University, Chicago, Illinois, USA
| | - David Bennett
- Rush Alzheimer's Disease Center, Rush University, Chicago, Illinois, USA
| | - William Honer
- BC Mental Health and Substance Use, Services Research Institute, Vancouver, British Columbia, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
3
|
Ito M, Yokoyama T, Hirakawa M, Yamamoto Y, Sakanoue W, Sato K, Saino T. Morphology and chemical characteristics of taste buds associated with P2X3-immunoreactive afferent nerve endings in the rat incisive papilla. J Anat 2022; 240:688-699. [PMID: 34719779 PMCID: PMC8930809 DOI: 10.1111/joa.13583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/16/2021] [Accepted: 10/22/2021] [Indexed: 11/30/2022] Open
Abstract
The present study investigated the cellular components and afferent innervations of taste buds in the rat incisive papilla by immunohistochemistry using confocal scanning laser microscopy. Taste buds containing guanine nucleotide-binding protein G(t), subunit α3 (GNAT3)-imunoreactive cells were densely distributed in the lateral wall of incisive papilla forming the opening of nasoincisor ducts. GNAT3-immunoreactive cells in the taste buds were slender in shape and the tips of apical processes gathered at one point at the surface of the epithelium. The number of taste buds was 56.8 ± 4.5 in the incisive papilla. The incisive taste buds also contained ectonucleoside triphosphate diphosphohydrolase 2-immunoreactive cells and synaptotagmin-1-immunoreactive cells in addition to GNAT3-immunoreactive cells. Furthermore, GNAT3-immunoreactive cells were immunoreactive to taste transduction molecules such as phospholipase C, β2-subunit, and inositol 1,4,5-trisphosphate receptor, type 3. P2X3-immunoreactive subepithelial nerve fibers intruded into the taste buds and terminated with hederiform or calix-like nerve endings attached to GNAT3-immunoreactive cells and synaptosomal-associated protein, 25 kDa-immunoreactive cells. Some P2X3-immunoreactive endings were also weakly immunoreactive for P2X2. Furthermore, a retrograde tracing method using fast blue dye indicated that most of the P2X3-immunoreactive nerve endings originated from the geniculate ganglia (GG) of the facial nerve. These results suggest that incisive taste buds are morphologically and cellularly homologous to lingual taste buds and are innervated by P2X3-immunoreactive nerve endings derived from the GG. The incisive papilla may be the palatal taste papilla that transmits chemosensory information in the oral cavity to the GG via P2X3-immunoreactive afferent nerve endings.
Collapse
Affiliation(s)
- Motoi Ito
- Division of Dental AnesthesiologyDepartment of Reconstructive Oral and Maxillofacial SurgerySchool of DentistryIwate Medical UniversityYahabaJapan
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology)Iwate Medical UniversityYahabaJapan
| | - Masato Hirakawa
- Department of Anatomy (Cell Biology)Iwate Medical UniversityYahabaJapan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell BiologyFaculty of AgricultureIwate UniversityMoriokaJapan
| | - Wakana Sakanoue
- Division of Dental AnesthesiologyDepartment of Reconstructive Oral and Maxillofacial SurgerySchool of DentistryIwate Medical UniversityYahabaJapan
| | - Kenichi Sato
- Division of Dental AnesthesiologyDepartment of Reconstructive Oral and Maxillofacial SurgerySchool of DentistryIwate Medical UniversityYahabaJapan
| | - Tomoyuki Saino
- Department of Anatomy (Cell Biology)Iwate Medical UniversityYahabaJapan
| |
Collapse
|
4
|
Yamamoto Y, Moriai H, Yokoyama T, Nakamuta N. Immunohistochemical distribution of proteins involved in glutamate release in subepithelial sensory nerve endings of rat epiglottis. Histochem Cell Biol 2021; 157:51-63. [PMID: 34613496 DOI: 10.1007/s00418-021-02038-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2021] [Indexed: 11/25/2022]
Abstract
To elucidate the efferent functions of sensory nerve endings, the distribution of calretinin and vesicular glutamate transporter 1 (VGLUT1) in laryngeal laminar nerve endings and the immunohistochemical distribution of proteins associated with synaptic vesicle release, i.e., t-SNARE (SNAP25 and syntaxin 1), v-SNARE (VAMP1 and VAMP2), synaptotagmin 1 (Syt1), bassoon, and piccolo, were examined. Subepithelial laminar nerve endings immunoreactive for Na+-K+-ATPase α3-subunit (NKAα3) were largely distributed in the whole-mount preparation of the epiglottic mucosa, and several endings were also immunoreactive for calretinin. VGLUT1 immunoreactivity was observed within terminal part near the outline of the small processes of NKAα3-immunoreactive nerve ending. SNAP25, syntaxin 1, and VAMP1 immunoreactivities were detected in terminal parts of calretinin-immunoreactive endings, whereas VAMP2 immunoreactivity was only observed in a few terminals. Terminal parts immunoreactive for calretinin and/or VGLUT1 also exhibited immunoreactivities for Syt1, Ca2+ sensor for membrane trafficking, and for bassoon and piccolo, presynaptic scaffold proteins. The presence of vesicular release-related proteins, including SNARE proteins, in the terminals of laryngeal laminar endings indicate that intrinsic glutamate modulates their afferent activity in an autocrine-like manner.
Collapse
Affiliation(s)
- Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate, 020-8550, Japan.
| | - Hisae Moriai
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate, 020-8550, Japan
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, 1-1-1 Idaidori, Yahaba, Iwate, 028-3694, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate, 020-8550, Japan
| |
Collapse
|
5
|
Ramos-Miguel A, Barakauskas V, Alamri J, Miyauchi M, Barr AM, Beasley CL, Rosoklija G, Mann JJ, Dwork AJ, Moradian A, Morin GB, Honer WG. The SNAP25 Interactome in Ventromedial Caudate in Schizophrenia Includes the Mitochondrial Protein ARF1. Neuroscience 2019; 420:97-111. [PMID: 30610939 DOI: 10.1016/j.neuroscience.2018.12.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/21/2018] [Accepted: 12/24/2018] [Indexed: 12/11/2022]
Abstract
Abnormalities of SNAP25 (synaptosome-associated protein 25) amount and protein-protein interactions occur in schizophrenia, and may contribute to abnormalities of neurotransmitter release in patients. However, presynaptic terminal function depends on multiple subcellular mechanisms, including energy provided by mitochondria. To explore the SNAP25 interactome in schizophrenia, we immunoprecipitated SNAP25 along with interacting proteins from the ventromedial caudate of 15 cases of schizophrenia and 13 controls. Proteins were identified with mass spectrometry-based proteomics. As well as 15 SNARE- (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) associated proteins, we identified 17 mitochondria-associated and four other proteins. The mitochondrial small GTPase ARF1 (ADP-ribosylation factor 1) was identified in eight schizophrenia SNAP25 immunoprecipitates and none from controls (P = 0.004). Although the ARF1-SNAP25 interaction may be increased, immunoblotting demonstrated 21% lower ARF1-21 (21 kiloDaltons) in schizophrenia samples (P = 0.04). In contrast, the mitochondrial protein UQCRC1 (ubiquinol-cytochrome c reductase core protein 1) did not differ. Lower ARF1-21 levels were associated with the previously reported increased SNAP25-syntaxin interaction in schizophrenia (r = -0.39, P = 0.04). Additional immunoprecipitation studies confirmed the ARF1-21-SNAP25 interaction, independent of UQCRC1. Both ARF1 and SNAP25 were localized to synaptosomes. Confocal microscopy demonstrated co-localization of ARF1 and SNAP25, and further suggested fivefold enrichment of ARF1 in synaptosomes containing an excitatory marker (vesicular glutamate transporter) compared with synaptosomes containing an inhibitory marker (vesicular GABA transporter). The present findings suggest an association between abnormalities of SNARE proteins involved with vesicular neurotransmission and the mitochondrial protein ARF1 that may contribute to the pathophysiology of schizophrenia.
Collapse
Affiliation(s)
- Alfredo Ramos-Miguel
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada; Department of Pharmacology, University of the Basque Country, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Barrio Sarriena, s/n, 48940 Leioa, Biscay, Spain
| | - Vilte Barakauskas
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, 2J9-4500 Oak St., Vancouver, BC V6H 3B1, Canada
| | - Jehan Alamri
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Masatoshi Miyauchi
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada
| | - Alasdair M Barr
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Anesthesiology, Pharmacology, & Therapeutics, University of British Columbia, 2176 Health Sciences Mall Vancouver, BC V6T 1Z3, Canada
| | - Clare L Beasley
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada
| | - Gorazd Rosoklija
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - J John Mann
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Andrew J Dwork
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Annie Moradian
- Department of Medical Genetics, University of British Columbia, C234-4500 Oak St., Vancouver, BC V6H 3B1, Canada
| | - Gregg B Morin
- Department of Medical Genetics, University of British Columbia, C234-4500 Oak St., Vancouver, BC V6H 3B1, Canada
| | - William G Honer
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada.
| |
Collapse
|
6
|
Ramos-Miguel A, Gicas K, Alamri J, Beasley CL, Dwork AJ, Mann JJ, Rosoklija G, Cai F, Song W, Barr AM, Honer WG. Reduced SNAP25 Protein Fragmentation Contributes to SNARE Complex Dysregulation in Schizophrenia Postmortem Brain. Neuroscience 2018; 420:112-128. [PMID: 30579835 DOI: 10.1016/j.neuroscience.2018.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
Abstract
Recent studies associated schizophrenia with enhanced functionality of the presynaptic SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex. Altered degradation pathways of the three core SNARE proteins: synaptosomal-associated protein 25 (SNAP25), syntaxin-1 and vesicle-associated membrane protein (VAMP) could contribute to enhanced complex function. To investigate these pathways, we first identified a 15-kDa SNAP25 fragment (f-S25) in human and rat brains, highly enriched in synaptosomal extractions, and mainly attached to cytosolic membranes with low hydrophobicity. The presence of f-S25 is consistent with reports of calpain-mediated SNAP25 cleavage. Co-immunoprecipitation assays showed that f-S25 retains the ability to bind syntaxin-1, which might prevent VAMP and/or Munc18-1 assembly into the complex. Quantitative analyses in postmortem human orbitofrontal cortex (OFC) revealed that schizophrenia (n = 35), but not major depression (n = 15), is associated with lower amounts of f-S25 (-37%, P = 0.027), and greater SNARE protein-protein interactions (35%, P < 0.001), compared with healthy matched controls (n = 28). Enhanced SNARE complex formation was strongly correlated with lower SNAP25 fragmentation rates (R = 0.563, P < 0.001). Statistical mediation analyses supported the hypothesis that reduced f-S25 density could upregulate SNARE fusion events in schizophrenia. Cortical calpain activity in schizophrenia did not differ from controls. f-S25 levels did not correlate with total calpain activity, indicating that if present, schizophrenia-related calpain dysfunction might occur locally at the presynaptic terminals. Overall, the present findings suggest the existence of an endogenous SNARE complex inhibitor related to SNAP25 proteolysis, associated with enhanced SNARE activity in schizophrenia.
Collapse
Affiliation(s)
- Alfredo Ramos-Miguel
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Biscay, Spain
| | - Kristina Gicas
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada
| | - Jehan Alamri
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Anesthesiology, Pharmacology, & Therapeutics, University of British Columbia, 2176 Health Sciences Mall Vancouver, BC V6T 1Z3, Canada
| | - Clare L Beasley
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada
| | - Andrew J Dwork
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - J John Mann
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Gorazd Rosoklija
- Department of Psychiatry, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Fang Cai
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada
| | - Weihong Song
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada
| | - Alasdair M Barr
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Anesthesiology, Pharmacology, & Therapeutics, University of British Columbia, 2176 Health Sciences Mall Vancouver, BC V6T 1Z3, Canada
| | - William G Honer
- BC Mental Health and Addictions Research Institute, 938 West 28th Ave, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 2A1, Canada.
| |
Collapse
|
7
|
Mine Y, Momiyama T, Hayashi T, Kawase T. Grafted Miniature-Swine Neural Stem Cells of Early Embryonic Mesencephalic Neuroepithelial Origin can Repair the Damaged Neural Circuitry of Parkinson's Disease Model Rats. Neuroscience 2018; 386:51-67. [PMID: 29932984 DOI: 10.1016/j.neuroscience.2018.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 06/02/2018] [Accepted: 06/04/2018] [Indexed: 12/21/2022]
Abstract
Although recent progress in the use of human iPS cell-derived midbrain dopaminergic progenitors is remarkable, alternatives are essential in the strategies of treatment of basal-ganglia-related diseases. Attention has been focused on neural stem cells (NSCs) as one of the possible candidates of donor material for neural transplantation, because of their multipotency and self-renewal characteristics. In the present study, miniature-swine (mini-swine) mesencephalic neuroepithelial stem cells (M-NESCs) of embryonic 17 and 18 days grafted in the parkinsonian rat striatum were assessed immunohistochemically, behaviorally and electrophysiologically to confirm their feasibility for the neural xenografting as a donor material. Grafted mini-swine M-NESCs survived in parkinsonian rat striatum at 8 weeks after transplantation and many of them differentiated into tyrosine hydroxylase (TH)-positive cells. The parkinsonian model rats grafted with mini-swine M-NESCs exhibited a functional recovery from their parkinsonian behavioral defects. The majority of donor-derived TH-positive cells exhibited a matured morphology at 8 weeks. Whole-cell recordings from donor-derived neurons in the host rat brain slices incorporating the graft revealed the presence of multiple types of neurons including dopaminergic. Glutamatergic and GABAergic post-synaptic currents were evoked in the donor-derived cells by stimulation of the host site, suggesting they receive both excitatory and inhibitory synaptic inputs from host area. The present study shows that non-rodent mammalian M-NESCs can differentiate into functionally active neurons in the diseased xenogeneic environment and could improve the parkinsonian behavioral defects over the species. Neuroepithelial stem cells could be an attractive candidate as a source of donor material for neural transplantation.
Collapse
Affiliation(s)
- Yutaka Mine
- Department of Neurosurgery and Endovascular Surgery, Brain Nerve Center, Saiseikai Yokohamashi Tobu Hospital, Yokohama 230-8765, Japan; Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan; Department of Neurosurgery, Keio University School of Medicine, Tokyo 160-8582, Japan; Department of Clinical Research, Tochigi Medical Center, National Hospital Organization, Utsunomiya 320-8580, Japan
| | - Toshihiko Momiyama
- Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki 444-8787, Japan; Department of Pharmacology, Jikei University School of Medicine, Tokyo 105-8461, Japan.
| | - Takuro Hayashi
- Department of Neurosurgery, Keio University School of Medicine, Tokyo 160-8582, Japan; Department of Neurosurgery, Tokyo Medical Center, National Hospital Organization, Tokyo 152-8902, Japan
| | - Takeshi Kawase
- Department of Neurosurgery, Keio University School of Medicine, Tokyo 160-8582, Japan
| |
Collapse
|
8
|
Ramos-Miguel A, Jones AA, Sawada K, Barr AM, Bayer TA, Falkai P, Leurgans SE, Schneider JA, Bennett DA, Honer WG. Frontotemporal dysregulation of the SNARE protein interactome is associated with faster cognitive decline in old age. Neurobiol Dis 2018; 114:31-44. [PMID: 29496544 PMCID: PMC6483375 DOI: 10.1016/j.nbd.2018.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/07/2018] [Accepted: 02/21/2018] [Indexed: 12/29/2022] Open
Abstract
The molecular underpinnings associated with cognitive reserve remain poorly understood. Because animal models fail to fully recapitulate the complexity of human brain aging, postmortem studies from well-designed cohorts are crucial to unmask mechanisms conferring cognitive resistance against cumulative neuropathologies. We tested the hypothesis that functionality of the SNARE protein interactome might be an important resilience factor preserving cognitive abilities in old age. Cognition was assessed annually in participants from the Rush "Memory and Aging Project" (MAP), a community-dwelling cohort representative of the overall aging population. Associations between cognition and postmortem neurochemical data were evaluated in functional assays quantifying various species of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) machinery in samples from the inferior temporal (IT, n = 154) and middle-frontal (MF, n = 174) gyri. Using blue-native gel electrophoresis, we isolated and quantified several types of complexes containing the three SNARE proteins (syntaxin-1, SNAP25, VAMP), as well as the GABAergic/glutamatergic selectively expressed complexins-I/II (CPLX1/2), in brain tissue homogenates and reconstitution assays with recombinant proteins. Multivariate analyses revealed significant associations between IT and MF neurochemical data (SNARE proteins and/or complexes), and multiple age-related neuropathologies, as well as with multiple cognitive domains of MAP participants. Controlling for demographic variables, neuropathologic indices and total synapse density, we found that temporal 150-kDa SNARE species (representative of pan-synaptic functionality) and frontal CPLX1/CPLX2 ratio of 500-kDa heteromeric species (representative of inhibitory/excitatory input functionality) were, among all the immunocharacterized complexes, the strongest predictors of cognitive function nearest death. Interestingly, these two neurochemical variables were associated with different cognitive domains. In addition, linear mixed effect models of global cognitive decline estimated that both 150-kDa SNARE levels and CPLX1/CPLX2 ratio were associated with better cognition and less decline over time. The results are consistent with previous studies reporting that synapse dysfunction (i.e. dysplasticity) may be initiated early, and relatively independent of neuropathology-driven synapse loss. Frontotemporal dysregulation of the GABAergic/glutamatergic stimuli might be a target for future drug development.
Collapse
Affiliation(s)
- Alfredo Ramos-Miguel
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada
| | - Andrea A Jones
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada
| | - Ken Sawada
- Kochi Medical School, Kohasu, Oko-cho, Nankoku, Kochi 783-8505, Japan
| | - Alasdair M Barr
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada; Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Thomas A Bayer
- Department of Psychiatry, University Medicine Goettingen, von-Siebold-Strasse 5, D-37075 Goettingen, Germany
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Nussbaumstrasse 7, D-80336 Munich, Germany
| | - Sue E Leurgans
- Rush Alzheimer's disease Center, Rush University Medical Center, 600 S. Paulina Street, Chicago, IL 60612, United States
| | - Julie A Schneider
- Rush Alzheimer's disease Center, Rush University Medical Center, 600 S. Paulina Street, Chicago, IL 60612, United States
| | - David A Bennett
- Rush Alzheimer's disease Center, Rush University Medical Center, 600 S. Paulina Street, Chicago, IL 60612, United States
| | - William G Honer
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada; Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada.
| |
Collapse
|
9
|
Yamamoto Y, Nakamuta N. Morphology of P2X3-immunoreactive nerve endings in the rat tracheal mucosa. J Comp Neurol 2017; 526:550-566. [PMID: 29124772 DOI: 10.1002/cne.24351] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/24/2017] [Accepted: 10/30/2017] [Indexed: 01/28/2023]
Abstract
Nerve endings with immunoreactivity for the P2X3 purinoreceptor (P2X3) in the rat tracheal mucosa were examined by immunohistochemistry of whole-mount preparations with confocal scanning laser microscopy. P2X3 immunoreactivity was observed in ramified endings distributed in the whole length of the trachea. The myelinated parent axons of P2X3-immunoreactive nerve endings ramified into several branches that extended two-dimensionally in every direction at the interface between the epithelial layer and lamina propria. The axonal branches of P2X3-immunoreactive endings branched off many twigs located just beneath the epithelium, and continued to intraepithelial axon terminals. The axon terminals of P2X3-immunoreactive endings were beaded, rounded, or club-like in shape and terminated between tracheal epithelial cells. Flat axon terminals sometimes partly ensheathed neuroendocrine cells with immunoreactivity for SNAP25 or CGRP. Some axons and axon terminals with P2X3 immunoreactivity were immunoreactive for P2X2, while some terminals were immunoreactive for vGLUT2. Furthermore, a retrograde tracing method using fast blue (FB) revealed that 88.4% of FB-labeled cells with P2X3 immunoreactivity originated from the nodose ganglion. In conclusion, P2X3-immunoreactive nerve endings in the rat tracheal mucosa have unique morphological characteristics, and these endings may be rapidly adapting receptors and/or irritant receptors that are activated by mucosal irritant stimuli.
Collapse
Affiliation(s)
- Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| |
Collapse
|
10
|
A Presynaptic Group III mGluR Recruits Gβγ/SNARE Interactions to Inhibit Synaptic Transmission by Cone Photoreceptors in the Vertebrate Retina. J Neurosci 2017; 37:4618-4634. [PMID: 28363980 DOI: 10.1523/jneurosci.2948-16.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 11/21/2022] Open
Abstract
G-protein βγ subunits (Gβγ) interact with presynaptic proteins and regulate neurotransmitter release downstream of Ca2+ influx. To accomplish their roles in sensory signaling, photoreceptor synapses use specialized presynaptic proteins that support neurotransmission at active zone structures known as ribbons. While several G-protein coupled receptors (GPCRs) influence synaptic transmission at ribbon synapses of cones and other retinal neurons, it is unknown whether Gβγ contributes to these effects. We tested whether activation of one particular GPCR, a metabotropic glutamate receptor (mGluR), can reduce cone synaptic transmission via Gβγ in tiger salamander retinas. In recordings from horizontal cells, we found that an mGluR agonist (L-AP4) reduced cone-driven light responses and mEPSC frequency. In paired recordings of cones and horizontal cells, L-AP4 slightly reduced cone ICa (∼10%) and caused a larger reduction in cone-driven EPSCs (∼30%). Proximity ligation assay revealed direct interactions between SNAP-25 and Gβγ subunits in retinal synaptic layers. Pretreatment with the SNAP-25 cleaving protease BoNT/A inhibited L-AP4 effects on synaptic transmission, as did introduction of a peptide derived from the SNAP-25 C terminus. Introducing Gβγ subunits directly into cones reduced EPSC amplitude. This effect was inhibited by BoNT/A, supporting a role for Gβγ/SNAP-25 interactions. However, the mGluR-dependent reduction in ICa was not mimicked by Gβγ, indicating that this effect was independent of Gβγ. The finding that synaptic transmission at cone ribbon synapses is regulated by Gβγ/SNAP-25 interactions indicates that these mechanisms are shared by conventional and ribbon-type synapses. Gβγ liberated from other photoreceptor GPCRs is also likely to regulate synaptic transmission.SIGNIFICANCE STATEMENT Dynamic regulation of synaptic transmission by presynaptic G-protein coupled receptors shapes information flow through neural circuits. At the first synapse in the visual system, presynaptic metabotropic glutamate receptors (mGluRs) regulate cone photoreceptor synaptic transmission, although the mechanisms and functional impact of this are unclear. We show that mGluRs regulate light response encoding across the cone synapse, accomplished in part by triggering G-protein βγ subunits (Gβγ) interactions with SNAP-25, a core component of the synaptic vesicle fusion machinery. In addition to revealing a role in visual processing, this provides the first demonstration that Gβγ/SNAP-25 interactions regulate synaptic function at a ribbon-type synapse, contributing to an emerging picture of the ubiquity of Gβγ/SNARE interactions in regulating synaptic transmission throughout the nervous system.
Collapse
|
11
|
Ramos-Miguel A, García-Sevilla JA, Barr AM, Bayer TA, Falkai P, Leurgans SE, Schneider JA, Bennett DA, Honer WG, García-Fuster MJ. Decreased cortical FADD protein is associated with clinical dementia and cognitive decline in an elderly community sample. Mol Neurodegener 2017; 12:26. [PMID: 28320441 PMCID: PMC5360099 DOI: 10.1186/s13024-017-0168-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/09/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND FADD (Fas-associated death domain) adaptor is a crucial protein involved in the induction of cell death but also mediates non-apoptotic actions via a phosphorylated form (p-Ser194-FADD). This study investigated the possible association of FADD forms with age-related neuropathologies, cognitive function, and the odds of dementia in an elderly community sample. METHODS FADD forms were quantified by western blot analysis in dorsolateral prefrontal cortex (DLPFC) samples from a large cohort of participants in a community-based aging study (Memory and Aging Project, MAP), experiencing no-(NCI, n = 51) or mild-(MCI, n = 42) cognitive impairment, or dementia (n = 57). RESULTS Cortical FADD was lower in subjects with dementia and lower FADD was associated with a greater load of amyloid-β pathology, fewer presynaptic terminal markers, poorer cognitive function and increased odds of dementia. Together with the observations of FADD redistribution into tangles and dystrophic neurites within plaques in Alzheimer's disease brains, and its reduction in APP23 mouse cortex, the results suggest this multifunctional protein might participate in the mechanisms linking amyloid and tau pathologies during the course of the illness. CONCLUSIONS The present data suggests FADD as a putative biomarker for pathological processes associated with the course of clinical dementia.
Collapse
Affiliation(s)
- Alfredo Ramos-Miguel
- BC Mental Health and Addictions Research Institute, Vancouver, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Jesús A. García-Sevilla
- IUNICS, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain
- Instituto de Investigación Sanitaria de Baleares, Palma de Mallorca, Spain
| | - Alasdair M. Barr
- BC Mental Health and Addictions Research Institute, Vancouver, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Thomas A. Bayer
- Department of Psychiatry, University Medicine Goettingen, Goettingen, Germany
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sue E. Leurgans
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, USA
| | - Julie A. Schneider
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, USA
| | - David A. Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, USA
| | - William G. Honer
- BC Mental Health and Addictions Research Institute, Vancouver, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - M. Julia García-Fuster
- IUNICS, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain
- Instituto de Investigación Sanitaria de Baleares, Palma de Mallorca, Spain
| |
Collapse
|
12
|
Ramos-Miguel A, Sawada K, Jones AA, Thornton AE, Barr AM, Leurgans SE, Schneider JA, Bennett DA, Honer WG. Presynaptic proteins complexin-I and complexin-II differentially influence cognitive function in early and late stages of Alzheimer's disease. Acta Neuropathol 2017; 133:395-407. [PMID: 27866231 PMCID: PMC6542594 DOI: 10.1007/s00401-016-1647-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/12/2016] [Accepted: 11/13/2016] [Indexed: 12/14/2022]
Abstract
Progressive accumulation of Alzheimer's disease-related pathology is associated with cognitive dysfunction. Differences in cognitive reserve may contribute to individual differences in cognitive function in the presence of comparable neuropathology. The protective effects of cognitive reserve could contribute differentially in early versus late stages of the disease. We investigated presynaptic proteins as measures of brain reserve (a subset of total cognitive reserve), and used Braak staging to estimate the progression of Alzheimer's disease. Antemortem evaluations of cognitive function, postmortem assessments of pathologic indices, and presynaptic protein analyses, including the complexins I and II as respective measures of inhibitory and excitatory terminal function, were assayed in multiple key brain regions in 418 deceased participants from a community study. After covarying for demographic variables, pathologic indices, and overall synapse density, lower brain complexin-I and -II levels contributed to cognitive dysfunction (P < 0.01). Each complexin appeared to be dysregulated at a different Braak stage. Inhibitory complexin-I explained 14.4% of the variance in global cognition in Braak 0-II, while excitatory complexin-II explained 7.3% of the variance in Braak V-VI. Unlike other presynaptic proteins, complexins did not colocalize with pathologic tau within neuritic plaques, suggesting that these functional components of the synaptic machinery are cleared early from dystrophic neurites. Moreover, complexin levels showed distinct patterns of change related to memory challenges in a rat model, supporting the functional specificity of these proteins. The present results suggest that disruption of inhibitory synaptic terminals may trigger early cognitive impairment, while excitatory terminal disruption may contribute relatively more to later cognitive impairment.
Collapse
Affiliation(s)
- Alfredo Ramos-Miguel
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada
| | - Ken Sawada
- Kochi Prefectural Aki General Hospital, 3-33 Hoheicho, Kochi, 784-0027, Japan
| | - Andrea A Jones
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada
| | - Allen E Thornton
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Psychology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Alasdair M Barr
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Sue E Leurgans
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600 S Paulina Street, Chicago, IL, 60612, USA
| | - Julie A Schneider
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600 S Paulina Street, Chicago, IL, 60612, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600 S Paulina Street, Chicago, IL, 60612, USA
| | - William G Honer
- BC Mental Health and Addictions Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada.
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada.
| |
Collapse
|
13
|
Ramos-Miguel A, Hercher C, Beasley CL, Barr AM, Bayer TA, Falkai P, Leurgans SE, Schneider JA, Bennett DA, Honer WG. Loss of Munc18-1 long splice variant in GABAergic terminals is associated with cognitive decline and increased risk of dementia in a community sample. Mol Neurodegener 2015; 10:65. [PMID: 26628003 PMCID: PMC4667524 DOI: 10.1186/s13024-015-0061-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/24/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Presynaptic terminals contribute to cognitive reserve, balancing the effects of age-related pathologies on cognitive function in the elderly. The presynaptic protein Munc18-1, alternatively spliced into long (M18L) or short (M18S) isoforms, is a critical modulator of neurotransmission. While subtle alterations in Munc18-1 have been shown to cause severe neuropsychiatric disorders with cognitive impairment, little information is known regarding the specific roles of Munc18-1 splice variants. We first investigated functional and anatomical features evidencing the divergent roles of M18L and M18S, and then evaluated their contribution to the full range of age-related cognitive impairment in the dorsolateral prefrontal cortex of a large sample of participants from a community-based aging study, including subjects with no-(NCI, n = 90), or mild-(MCI, n = 86) cognitive impairment, or with clinical dementia (n = 132). Finally, we used APP23 mutant mice to study the association between M18L/S and the time-dependent accumulation of common Alzheimer's disease pathology. RESULTS Using isoform-specific antibodies, M18L was localized to the synaptosomal fraction, with a distribution matching lipid raft microdomains. M18S was found widely across cytosolic and synaptosomal compartments. Immunocytochemical studies identified M18L in perisomatic, GABAergic terminals, while M18S was broadly distributed in GABAergic and glutamatergic terminals. Using regression models taking into account multiple age-related pathologies, age, education and sex, global cognitive function was associated with the level of M18L (p = 0.006) but not M18S (p = 0.88). Mean M18L in dementia cases was 51 % lower than in NCI cases (p < 0.001), and each unit of M18L was associated with a lower likelihood of dementia (odds ratio = 0.68, 95 % confidence interval = 0.50-0.90, p = 0.008). In contrast, M18S balanced across clinical and pathologically diagnosed groups. M18L loss may not be caused by age-related amyloid pathology, since APP23 mice (12- and 22-months of age) had unchanged cortical levels of M18L/S compared with wild-type animals. CONCLUSIONS M18L was localized to presynaptic inhibitory terminals, and was associated with cognitive function and protection from dementia in an elderly, community-based cohort. Lower M18L in inhibitory presynaptic terminals may be an early, independent contributor to cognitive decline.
Collapse
Affiliation(s)
- Alfredo Ramos-Miguel
- Child and Family Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada. .,Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada.
| | - Christa Hercher
- Child and Family Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada. .,Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada.
| | - Clare L Beasley
- Child and Family Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada. .,Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada.
| | - Alasdair M Barr
- Child and Family Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada. .,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
| | - Thomas A Bayer
- Department of Psychiatry, University Medicine Goettingen, von-Siebold-Strasse 5, D-37075, Goettingen, Germany.
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Nussbaumstrasse 7, D-80336, Munich, Germany.
| | - Sue E Leurgans
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600S. Paulina Street, IL, 60612, Chicago, USA.
| | - Julie A Schneider
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600S. Paulina Street, IL, 60612, Chicago, USA.
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600S. Paulina Street, IL, 60612, Chicago, USA.
| | - William G Honer
- Child and Family Research Institute, 938 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada. .,Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 2A1, Canada.
| |
Collapse
|
14
|
Nerve terminal nicotinic acetylcholine receptors initiate quantal GABA release from perisomatic interneurons by activating axonal T-type (Cav3) Ca²⁺ channels and Ca²⁺ release from stores. J Neurosci 2011; 31:13546-61. [PMID: 21940446 DOI: 10.1523/jneurosci.2781-11.2011] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Release of conventional neurotransmitters is mainly controlled by calcium (Ca²⁺) influx via high-voltage-activated (HVA), Ca(v)2, channels ("N-, P/Q-, or R-types") that are opened by action potentials. Regulation of transmission by subthreshold depolarizations does occur, but there is little evidence that low-voltage-activated, Ca(v)3 ("T-type"), channels take part. GABA release from cortical perisomatic-targeting interneurons affects numerous physiological processes, and yet its underlying control mechanisms are not fully understood. We investigated whether T-type Ca²⁺ channels are involved in regulating GABA transmission from these cells in rat hippocampal CA1 using a combination of whole-cell voltage-clamp, multiple-fluorescence confocal microscopy, dual-immunolabeling electron-microscopy, and optogenetic methods. We show that Ca(v)3.1, T-type Ca²⁺ channels can be activated by α3β4 nicotinic acetylcholine receptors (nAChRs) that are located on the synaptic regions of the GABAergic perisomatic-targeting interneuronal axons, including the parvalbumin-expressing cells. Asynchronous, quantal GABA release can be triggered by Ca²⁺ influx through presynaptic T-type Ca²⁺ channels, augmented by Ca²⁺ from internal stores, following focal microiontophoretic activation of the α3β4 nAChRs. The resulting GABA release can inhibit pyramidal cells. The T-type Ca²⁺ channel-dependent mechanism is not dependent on, or accompanied by, HVA channel Ca²⁺ influx, and is insensitive to agonists of cannabinoid, μ-opioid, or GABA(B) receptors. It may therefore operate in parallel with the normal HVA-dependent processes. The results reveal new aspects of the regulation of GABA transmission and contribute to a deeper understanding of ACh and nicotine actions in CNS.
Collapse
|
15
|
VAMP-2, SNAP-25A/B and syntaxin-1 in glutamatergic and GABAergic synapses of the rat cerebellar cortex. BMC Neurosci 2011; 12:118. [PMID: 22094010 PMCID: PMC3228762 DOI: 10.1186/1471-2202-12-118] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 11/17/2011] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The aim of this study was to assess the distribution of key SNARE proteins in glutamatergic and GABAergic synapses of the adult rat cerebellar cortex using light microscopy immunohistochemical techniques. Analysis was made of co-localizations of vGluT-1 and vGluT-2, vesicular transporters of glutamate and markers of glutamatergic synapses, or GAD, the GABA synthetic enzyme and marker of GABAergic synapses, with VAMP-2, SNAP-25A/B and syntaxin-1. RESULTS The examined SNARE proteins were found to be diffusely expressed in glutamatergic synapses, whereas they were rarely observed in GABAergic synapses. However, among glutamatergic synapses, subpopulations which did not contain VAMP-2, SNAP-25A/B and syntaxin-1 were detected. They included virtually all the synapses established by terminals of climbing fibres (immunoreactive for vGluT-2) and some synapses established by terminals of parallel and mossy fibres (immunoreactive for vGluT-1, and for vGluT-1 and 2, respectively). The only GABA synapses expressing the SNARE proteins studied were the synapses established by axon terminals of basket neurons. CONCLUSION The present study supplies a detailed morphological description of VAMP-2, SNAP-25A/B and syntaxin-1 in the different types of glutamatergic and GABAergic synapses of the rat cerebellar cortex. The examined SNARE proteins characterize most of glutamatergic synapses and only one type of GABAergic synapses. In the subpopulations of glutamatergic and GABAergic synapses lacking the SNARE protein isoforms examined, alternative mechanisms for regulating trafficking of synaptic vesicles may be hypothesized, possibly mediated by different isoforms or homologous proteins.
Collapse
|
16
|
Tsang CW, Estey MP, DiCiccio JE, Xie H, Patterson D, Trimble WS. Characterization of presynaptic septin complexes in mammalian hippocampal neurons. Biol Chem 2011; 392:739-49. [PMID: 21767234 DOI: 10.1515/bc.2011.077] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Septins are GTPases that form heteromeric complexes and are linked to neurological disorders. Although several septin subcomplexes have been reported in various mammalian tissues, the cellular and subcellular distribution of these complexes is largely unexplored. Using antibodies against ten mammalian septins, we show that septins diverge with respect to their tissue distribution implying that septin complexes in various tissues have unique composition. Although all ten septins examined were expressed in brain tissue, we describe septin complex(es) including SEPT3, SEPT5, SEPT6, SEPT7 and SEPT11 that could be functional within the presynapse because, unlike other septins they: (1) showed an increase in expression from embryonic day 15 to post-natal day 70, (2) were abundantly expressed in axons and growth cones of developing hippocampal neurons, (3) were found in presynaptic terminals of mature synapses, (4) were enriched in a preparation of synaptic vesicles and (5) immunoprecipitated together from brain tissue and cultured nerve cells. Knockdown of SEPT5 or SEPT7 in developing hippocampal neurons impaired axon growth. Because septins are functionally linked to the cytoskeleton and vesicle traffic, presynaptic neuronal septin complexes could be important for ensuring proper axon development and neurotransmitter release.
Collapse
|
17
|
Hirano AA, Brandstätter JH, Morgans CW, Brecha NC. SNAP25 expression in mammalian retinal horizontal cells. J Comp Neurol 2011; 519:972-88. [PMID: 21280047 DOI: 10.1002/cne.22562] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Horizontal cells mediate inhibitory feedforward and feedback lateral interactions in the outer retina at photoreceptor terminals and bipolar cell dendrites; however, the mechanisms that underlie synaptic transmission from mammalian horizontal cells are poorly understood. The localization of a vesicular γ-aminobutyric acid (GABA) transporter (VGAT) to horizontal cell processes in primate and rodent retinae suggested that mammalian horizontal cells release transmitter in a vesicular manner. Toward determining whether the molecular machinery for vesicular transmitter release is present in horizontal cells, we investigated the expression of SNAP25 (synaptosomal-associated protein of 25 kDa), a key SNARE protein, by immunocytochemistry with cell type-specific markers in the retinae of mouse, rat, rabbit, and monkey. Different commercial antibodies to SNAP25 were tested on vertical sections of retina. We report the robust expression of SNAP25 in both plexiform layers. Double labeling with SNAP25 and calbindin antibodies demonstrated that horizontal cell processes and their endings in photoreceptor triad synapses were strongly labeled for both proteins in mouse, rat, rabbit, and monkey retinae. Double labeling with parvalbumin antibodies in monkey retina verified SNAP25 immunoreactivity in all horizontal cells. Pre-embedding immunoelectron microscopy in rabbit retina confirmed expression of SNAP25 in lateral elements within photoreceptor triad synapses. The SNAP25 immunoreactivity in the plexiform layers and outer nuclear layer fell into at least three patterns depending on the antibody, suggesting a differential distribution of SNAP25 isoforms. The presence of SNAP25a and SNAP25b isoforms in mouse retina was established by reverse transcriptase-polymerase chain reaction. SNAP25 expression in mammalian horizontal cells along with other SNARE proteins is consistent with vesicular exocytosis.
Collapse
Affiliation(s)
- Arlene A Hirano
- Department of Neurobiology, David Geffen School of Medicine at the University of California-Los Angeles, Los Angeles, California 90095, USA.
| | | | | | | |
Collapse
|
18
|
Griffin GD, Ferri-Kolwicz SL, Reyes BAS, Van Bockstaele EJ, Flanagan-Cato LM. Ovarian hormone-induced reorganization of oxytocin-labeled dendrites and synapses lateral to the hypothalamic ventromedial nucleus in female rats. J Comp Neurol 2011; 518:4531-45. [PMID: 20886620 DOI: 10.1002/cne.22470] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Central oxytocin (OT) modulates many social behaviors, including female rat sexual receptivity, quantified as the copulatory stance known as lordosis. The expression of the lordosis response is modulated by OT action in the ventromedial nucleus of the hypothalamus (VMH), as demonstrated by behavioral pharmacology experiments. However, the subcellular localization of OT in this brain region has been unclear. We tested the hypothesis that ovarian hormones reorganize OT-labeled pre- or postsynaptic elements in the fiber complex lateral to the VMH by using immunoelectron microscopy. OT immunolabeling occurred in axonal boutons identified by the presence of small, clear synaptic vesicles and double labeling with the presynaptic markers synaptophysin and vesicular glutamate transporter 2. OT immunoreactivity also was observed in dendritic profiles, verified with double labeling for the dendrite-specific marker microtubule-associated protein 2. Ovarian hormones did not alter the density of axonal boutons; however, estradiol treatment reduced the density of dendritic profiles by 34%. This effect was reversed when progesterone was given subsequent to estradiol. The effect of estradiol treatment was specific to dendrites that lacked OT immunostaining; the density of OT-labeled dendritic profiles remained constant during estradiol treatment. With the estradiol-induced exit of non-OT-labeled dendritic profiles, the remaining OT-labeled dendritic profiles experienced an increase in their number of synaptic contacts. Thus, hormone treatments that mimic the 4-day rat estrous cycle provoke a chemically coded reorganization of dendrite innervation in the fiber plexus lateral to the VMH that may underlie the hormone-specific effect of OT on reproductive behavior.
Collapse
Affiliation(s)
- Gerald D Griffin
- Neuroscience Graduate Group, Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6241, USA.
| | | | | | | | | |
Collapse
|
19
|
Park HJ, Park HW, Lee SJ, Arevalo JC, Park YS, Lee SP, Paik KS, Chao MV, Chang MS. Ankyrin repeat-rich membrane spanning/Kidins220 protein interacts with mammalian Septin 5. Mol Cells 2010; 30:143-8. [PMID: 20680483 DOI: 10.1007/s10059-010-0099-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 05/06/2010] [Accepted: 05/07/2010] [Indexed: 11/29/2022] Open
Abstract
Neurotrophin receptors utilize specific adaptor proteins to activate signaling pathways involved in various neuronal functions, such as neurite outgrowth and cytoskeletal remodeling. The Ankyrin-Repeat Rich Membrane Spanning (ARMS)/kinase D-interacting substrate-220 kDa (Kidins220) serves as a unique downstream adaptor protein of Trk receptor tyrosine kinases. To gain insight into the role of ARMS/Kidins220, a yeast two-hybrid screen of a rat dorsal root ganglion library was performed using the C-terminal region of ARMS/Kidins220 as bait. The screen identified a mammalian septin, Septin 5 (Sept5), as an interacting protein. Co-immunoprecipitation using lysates from transiently transfected HEK-293 cells revealed the specific interaction between ARMS/Kidins220 and Sept5. Endogenous ARMS/Kidins220 and Sept5 proteins were colocalized in primary hippocampal neurons and were also predominantly expressed at the plasma membrane and in the tips of growing neurites in nerve growth factor-treated PC12 cells. Mapping of Sept5 domains important for ARMS/Kidins220 binding revealed a highly conserved N-terminal region of Sept5. The direct interaction between ARMS/Kidins220 and Sept5 suggests a possible role of ARMS/Kidins220 as a functional link between neurotrophin receptors and septins to mediate neurotrophin-induced intracellular signaling events, such as neurite outgrowth and cytoskeletal remodeling.
Collapse
Affiliation(s)
- Han Jeong Park
- Department of Oral Anatomy, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Synaptic cross talk between perisomatic-targeting interneuron classes expressing cholecystokinin and parvalbumin in hippocampus. J Neurosci 2009; 29:4140-54. [PMID: 19339609 DOI: 10.1523/jneurosci.5264-08.2009] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cholescystokinin (CCK)- or parvalbumin (PV)-containing interneurons are the major perisomatic-targeting interneurons in the cerebral cortex, including hippocampus, and are thought to form mutually exclusive networks. We used several techniques to test the alternative hypothesis that CCK and PV cells are coupled by chemical synapses. Triple immunofluorescence confocal microscopy revealed numerous axosomatic, axodendritic, and axoaxonic contacts stained for CCK, PV, and the presynaptic marker synaptophysin. The existence of mutual CCK and PV synapses was supported by dual EM immunolabeling. Paired whole-cell recordings detected unitary GABA(A)ergic synaptic transmission between identified CCK and PV cells, and single CCK cells could transiently inhibit action potential firing of synaptically coupled PV cells. We conclude that the major hippocampal perisomatic-targeting interneurons communicate synaptically. This communication should affect neuronal network activity, including neuronal oscillations, in which the CCK and PV cells have well established roles. The prevalence of CCK and PV networks in other brain regions suggests that internetwork interactions could be generally important.
Collapse
|
21
|
Barr AM, Fish KN, Markou A, Honer WG. Heterozygous reeler mice exhibit alterations in sensorimotor gating but not presynaptic proteins. Eur J Neurosci 2008; 27:2568-74. [PMID: 18547243 DOI: 10.1111/j.1460-9568.2008.06233.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Post mortem, reduced brain reelin is noted in schizophrenia. Accordingly, the reelin-haploinsufficient heterozygous reeler mouse (HRM) has been posited as a murine model of the illness. One study reported that HRM exhibit deficits in prepulse inhibition (PPI) of the acoustic startle reflex, a sensorimotor-gating behavior that is disrupted in schizophrenia, although this finding has not been reproduced. To extend the characterization of putative sensorimotor-gating deficits in HRM, these mice were subjected to a sophisticated series of PPI tests. Mice were tested in a cross-modal PPI protocol that combined an acoustic prepulse with a tactile startle stimulus and also in a protocol that included varying prepulse-pulse intervals and varying acoustic startle pulse intensities. Levels of acoustic startle habituation and cross-modal PPI were significantly lower in HRM, although unimodal PPI did not differ. The HRM also exhibited increased PPI compared to wildtypes at short interstimulus intervals between prepulse and pulse stimuli when the interval between the acoustic prepulse and pulse were varied, and were more reactive to higher intensity startle stimuli. Some of these deficits in sensorimotor gating parallel those of schizophrenia, a disease characterized by alterations in synaptic protein expression. Therefore, levels of presynaptic proteins were measured in multiple brain regions using ELISA in HRM. No significant alterations in presynaptic protein expression were found. Thus, HRM exhibit a complex pattern of changes in startle reactivity and sensorimotor gating, with both similarities to and differences from schizophrenia. However, it is unlikely that these behavioral differences may be accounted for by altered regional levels of presynaptic proteins.
Collapse
Affiliation(s)
- Alasdair M Barr
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3.
| | | | | | | |
Collapse
|
22
|
Garbelli R, Inverardi F, Medici V, Amadeo A, Verderio C, Matteoli M, Frassoni C. Heterogeneous expression of SNAP-25 in rat and human brain. J Comp Neurol 2008; 506:373-86. [PMID: 18041776 DOI: 10.1002/cne.21505] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Synaptosomal associated protein of 25 kDa (SNAP-25) is a SNARE component of the exocytotic apparatus involved in the release of neurotransmitter. We used multiple-labeling immunofluorescence, confocal microscopy, and ultrastructural immunocytochemistry to examine the expression of SNAP-25 in excitatory and inhibitory terminals from different rat and human brain areas. Glutamatergic and GABAergic terminals were identified by staining for the vesicular glutamate transporter (vGLUT1), glutamic acid decarboxylase (GAD67), or the vesicular GABA transporter (vGAT). In all examined areas GABAergic terminals did not display detectable levels of SNAP-25, whereas glutamatergic terminals expressed the protein to a variable extent. Codistribution analysis revealed a high colocalization between pixels detecting SNAP-25 labeling and pixels detecting vGLUT1 immunoreactivity. On the contrary, a low degree of pixel colocalization, comparable to that between two unrelated antigens, was detected between SNAP-25 and vGAT, thus suggesting a random overlap of immunofluorescence signals. Our immunofluorescence evidence was supported by ultrastructural data, which clearly confirmed that SNAP-25 was undetectable in GABAergic terminals identified by both their typical morphology and specific staining for GABA. Interestingly, our ultrastructural results confirmed that a subset of glutamatergic synapses do not contain detectable levels of SNAP-25. The present study extends our previous findings obtained in rodent hippocampus and provides evidence that SNAP-25 expression is highly variable between different axon terminals both in rat and human brain. The heterogeneous distribution of SNAP-25 may have important implications not only in relation to the function of the protein as a SNARE but also in the control of network excitability.
Collapse
Affiliation(s)
- Rita Garbelli
- Clinical Epileptology and Experimental Neurophysiology Unit, Fondazione IRCCS, Istituto Neurologico C Besta, via Celoria 11, Milano, Italy
| | | | | | | | | | | | | |
Collapse
|
23
|
Cai F, Chen B, Zhou W, Zis O, Liu S, Holt RA, Honer WG, Song W. SP1 regulates a human SNAP-25 gene expression. J Neurochem 2008; 105:512-23. [PMID: 18194215 DOI: 10.1111/j.1471-4159.2007.05167.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synaptosomal-associated protein of 25 kDa (SNAP-25) is a pre-synaptic plasma membrane protein. SNAP-25 plays an important role in synaptic vesicle membrane docking and fusion, which is involved in the regulation of neurotransmitter release. SNAP-25 has been implicated in the pathogenesis of neuropsychiatric disorders including Schizophrenia, attention-deficit hyperactivity disorder and Alzheimer's disease. We cloned a 1584 bp segment of the 5' flanking region of the human SNAP-25 gene. A series of nested deletions of the 5' flanking region fragment were subcloned into the pGL3-basic luciferase reporter plasmid. N2A cells were transfected with the SNAP-25 promoter constructs and luciferase activity was measured as an indication of promoter activity. We identified a 188 bp fragment containing the transcription initiation site as the minimal region necessary for promoter activity. Several putative cis-acting elements including SP1, hypoxia inducible factor (HIF), cAMP-response element binding protein, T-cell factor/lymphocyte enhancer factor 1 (TCF/LEF1), AP1 and the signal transducer and activator of transcription-6 (STAT6) are found in the 5' flanking region of SNAP-25 gene. Transcriptional activation and gel shift assays showed that the human SNAP-25 gene promoter contains functional SP1 response elements. Over-expression of SP1 increased SNAP-25 gene expression and inhibition of SP1-mediated transcriptional activation reduced SNAP-25 gene expression. These results suggest that SP1 plays an important role in regulation of the human SNAP-25 gene expression.
Collapse
Affiliation(s)
- Fang Cai
- Department of Psychiatry, Brain Research Center, The University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Kirouac GJ, Parsons MP, Li S. Innervation of the paraventricular nucleus of the thalamus from cocaine- and amphetamine-regulated transcript (CART) containing neurons of the hypothalamus. J Comp Neurol 2006; 497:155-65. [PMID: 16705679 DOI: 10.1002/cne.20971] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The paraventricular nucleus of the thalamus (PVT) is a midline thalamic nucleus with heavy projections to the nucleus accumbens and other limbic regions. Previous studies have shown that the PVT contains fibers immunoreactive for cocaine- and amphetamine-related transcript (CART). The purpose of the present study was to determine the location of CART neurons innervating the PVT of the rat by using retrograde tracing with cholera toxin B (CTb) combined with immunofluorescence for CTb and CART (amino acid sequence 55-102). Immunohistochemical analysis of CART in the dorsal thalamus showed that the PVT is densely innervated by CART fibers whereas adjacent midline and intralaminar thalamic nuclei are unlabeled. Injections of CTb in the dorsal midline thalamus retrogradely labeled neurons in several areas of the hypothalamus and brainstem which also contained CART neurons. The largest number of double-labeled neurons (CTb/CART) was found in the arcuate nucleus of the hypothalamus. CTb/CART neurons were also found in the lateral hypothalamus, zona incerta, and periventricular hypothalamus. These results indicate that the arcuate nucleus is a major source of CART fibers in the PVT. CART neurons in the arcuate nucleus monitor circulating hormonal signals and may regulate food intake and hypothalamic-pituitary-adrenal (HPA) activity. Consequently, CART neurons in the arcuate nucleus may transmit signals to the PVT which in turn may influence limbic regions involved in regulating food intake and the HPA.
Collapse
Affiliation(s)
- Gilbert J Kirouac
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
| | | | | |
Collapse
|
25
|
Sadakata T, Itakura M, Kozaki S, Sekine Y, Takahashi M, Furuichi T. Differential distributions of the Ca2+ -dependent activator protein for secretion family proteins (CAPS2 and CAPS1) in the mouse brain. J Comp Neurol 2006; 495:735-53. [PMID: 16506193 DOI: 10.1002/cne.20947] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The Ca(2+)-dependent activator protein for secretion (CAPS/Cadps) family consists of two members, CAPS1 and CAPS2, and plays an important role in secretory granule exocytosis. It has been shown that CAPS1 regulates catecholamine release from neuroendocrine cells, whereas CAPS2 is involved in the release of two neurotrophins, brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), from parallel fibers of cerebellar granule cells. Although both CAPS proteins are expressed predominantly in the brain, their cellular and regional distributions in the brain are largely unknown. In this study we analyzed the immunohistochemical distributions of the CAPS family proteins in the mouse brain. In most areas of the embryonic nervous system CAPS1 and CAPS2 proteins were complementarily expressed. In the postnatal brain, CAPS1 was widespread at different levels. On the other hand, CAPS2 was localized to distinct cell types and fibers of various brain regions, including the olfactory bulb, cerebrum, hippocampal formation, thalamus, mesencephalic tegmentum, cerebellum, medulla, and spinal cord, except for some regions that overlapped with CAPS1. These CAPS2 cellular distribution patterns had the marked feature of coinciding with those of BDNF in various brain regions. Immunolabels for CAPS2 were also colocalized with those for some proteins related to exocytosis (VAMP and SNAP-25) and endocytosis (Dynamin I) in the cell soma and processes of the mesencephalic tegmentum and cerebellum, suggesting that these proteins might be involved in the dynamics of CAPS2-associated vesicles, although their colocalization on vesicles remains elusive. These results demonstrate that the CAPS family proteins are involved in the secretion of different secretory substances in developing and postnatal brains, and that CAPS2 is probably involved in BDNF secretion in many brain areas.
Collapse
Affiliation(s)
- Tetsushi Sadakata
- Laboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako, Saitama 351-1098, Japan
| | | | | | | | | | | |
Collapse
|
26
|
Matsui T, Ramasamy K, Ingelsson M, Fukumoto H, Conrad C, Frosch MP, Irizarry MC, Yuan J, Hyman BT. Coordinated Expression of Caspase 8, 3 and 7 mRNA in Temporal Cortex of Alzheimer Disease: Relationship to Formic Acid Extractable Aβ42 Levels. J Neuropathol Exp Neurol 2006; 65:508-15. [PMID: 16772874 DOI: 10.1097/01.jnen.0000229238.05748.12] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Recent studies support the hypothesis that Alzheimer disease (AD)-associated amyloid-beta protein (Abeta) may induce apoptosis mediated by a caspase cascade. To assess whether mRNA levels of caspase-3, 7, 8 and 9 change in AD brain, and whether these changes correlate with neurofibrillary tangles, Abeta40 or Abeta42 protein levels or senile plaques, 25 AD and 21 non-demented control brains were examined. Elevated mRNA levels of caspases-7 and 8 measured by a quantitative PCR method were observed in the AD temporal neocortex as compared to the control brains. No significant differences were noticed in levels of caspases-3 or 9 between AD and control brains. Multiple regression analysis demonstrated that, within subjects, the mRNA levels of caspase-8 strongly correlated with both caspse-3 and caspase-7 independently of postmortem interval. Further, there was a strong positive correlation of caspase-8 levels with formic acid extractable Abeta42 levels. Our results suggest that the transcriptional activation of key components of the apoptotic cascade correlates with accumulation of Abeta 42. Thus, a principal caspase pathway from caspase-8 to caspase-3 and/or 7 may contribute to neuron loss in AD brain.
Collapse
Affiliation(s)
- Toshifumi Matsui
- Alzheimer Research Unit, Mass General Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
King AE, Chung RS, Vickers JC, Dickson TC. Localization of glutamate receptors in developing cortical neurons in culture and relationship to susceptibility to excitotoxicity. J Comp Neurol 2006; 498:277-94. [PMID: 16856139 DOI: 10.1002/cne.21053] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Overactivation of glutamate receptors leading to excitotoxicity has been implicated in the neurodegenerative alterations of a range of central nervous system (CNS) disorders. We have investigated the cell-type-specific changes in glutamate receptor localization in developing cortical neurons in culture, as well as the relationship between glutamate receptor subunit distribution with synapse formation and susceptibility to excitotoxicity. Glutamate receptor subunit clustering was present prior to the formation of synapses. However, different receptor types showed distinctive temporal patterns of subunit clustering, localization to spines, and apposition to presynaptic terminals. N-methyl-D-aspartate (NMDA) receptor subunit immunolabelling was present in puncta along dendrites prior to the formation of synapses, with relatively little localization to spines. Vulnerability to NMDA receptor-mediated excitotoxicity occurred before receptor subunits became localized in apposition to presynaptic terminals. Clustering of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors occurred concurrently with development of vulnerability to excitotoxicity and was related to localization of AMPA receptors at synapses and in spines. Different AMPA receptor subunits demonstrated cell-type-specific localization as well as distribution to spines, dendrites, and extrasynaptic subunit clusters. A subclass of neurons demonstrated substantial perineuronal synaptic innervation, and these neurons expressed relatively high levels of GluR1 and/or GluR4 at receptor puncta, indicating the presence of calcium-permeable AMPA receptors and suggesting alternative synaptic signalling mechanisms and vulnerability to excitotoxicity. These data demonstrate the relationship between glutamate receptor subunit expression and localization with synaptogenesis and development of neuronal susceptibility to excitotoxicity. These data also suggest that excitotoxicity can be mediated through extrasynaptic receptor subunit complexes along dendrites.
Collapse
Affiliation(s)
- A E King
- NeuroRepair Group, University of Tasmania, Hobart, Tasmania 7001, Australia
| | | | | | | |
Collapse
|
28
|
Beites C, Campbell K, Trimble W. The septin Sept5/CDCrel-1 competes with alpha-SNAP for binding to the SNARE complex. Biochem J 2005; 385:347-53. [PMID: 15355307 PMCID: PMC1134704 DOI: 10.1042/bj20041090] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) proteins are supposed to mediate the docking and/or fusion of the vesicle with the plasma membrane. However, it is not clearly understood how this process is regulated. In a search for potential SNARE regulators, we recently identified septin 5 (Sept5) as a novel SNARE interacting protein. Septins were first identified as filamentous proteins required for cytokinesis in yeast. Several septins have now been identified in mammals but little is known about their functions. We have previously shown that Sept5 is predominantly expressed in the brain, where it associates with vesicles and membranes through its interaction with the SNARE domain of syntaxin 1A. Furthermore, Sept5 appears to inhibit exocytosis, possibly by regulating vesicle targeting and/or fusion events. To gain insight into the role of Sept5, we have mapped the Sept5 domains important for syntaxin binding. We also investigated the ability of Sept5 to bind to syntaxin when in various protein complexes. Although Sept5 cannot bind an nSec1-syntaxin complex, it can bind syntaxin in a SNARE complex. This interaction is occluded by the binding of alpha-SNAP, suggesting that Sept5 may regulate the availability of SNARE proteins through its interaction with syntaxin and the 7 S complex.
Collapse
Affiliation(s)
- Crestina L. Beites
- *Programme in Cell Biology, Hospital for Sick Children, 555 University Avenue, Toronto, Canada M5G 1X8
- †Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Kristen A. Campbell
- *Programme in Cell Biology, Hospital for Sick Children, 555 University Avenue, Toronto, Canada M5G 1X8
- †Department of Biochemistry, University of Toronto, Toronto, Canada
| | - William S. Trimble
- *Programme in Cell Biology, Hospital for Sick Children, 555 University Avenue, Toronto, Canada M5G 1X8
- †Department of Biochemistry, University of Toronto, Toronto, Canada
- To whom correspondence should be addressed (email )
| |
Collapse
|
29
|
Barr AM, Young CE, Sawada K, Trimble WS, Phillips AG, Honer WG. Abnormalities of presynaptic protein CDCrel-1 in striatum of rats reared in social isolation: relevance to neural connectivity in schizophrenia. Eur J Neurosci 2004; 20:303-7. [PMID: 15245502 DOI: 10.1111/j.0953-816x.2004.03457.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Post-weaning social isolation-rearing of rats leads to behavioural and neurochemical sequelae that model aspects of schizophrenia, and it may be useful to test hypotheses related to putative molecular mechanisms of the illness. In humans, the presynaptic protein CDCrel-1 represents an interesting candidate molecule for the mechanism and aetiology of schizophrenia. CDCrel-1 modulates dopamine neurotransmission, binds to the SNARE protein syntaxin and maps onto a region of chromosome 22q11 deleted in velo-cardio-facial and DiGeorge syndromes, which are associated with increased prevalence of schizophrenia. Using the isolation-rearing model, we measured immunoreactivity of the synaptic proteins CDCrel-1, synaptophysin and syntaxin. Male, Sprague-Dawley rats were raised in groups or in isolation for 12 weeks from weaning. Synaptic protein immunoreactivities were measured in striatal and hippocampal homogenates, using a sensitive enzyme-linked immunoadsorbent assay with monoclonal antibodies. Isolation-rearing produced region- and protein-specific effects. CDCrel-1 immunoreactivity was significantly lower in the striatum and marginally higher in the hippocampus of isolation-reared compared with socially reared animals. There were no statistically significant differences in synaptophysin immunoreactivity in either region. Confocal microscopy demonstrated a high degree of colocalization between the two presynaptic proteins. In striatum, a robust relationship between CDCrel-1 and syntaxin immunoreactivities was observed in socially reared rats, this was lost in the isolation-reared animals. Altered levels of the septin CDCrel-1 in isolation-reared rats may contribute to changes in neuronal connectivity and neurotransmission, and suggest a potential role for CDCrel-1 in schizophrenia related to chromosome 22q11 deletion syndrome.
Collapse
Affiliation(s)
- Alasdair M Barr
- Centre for Complex Disorders, University of British Columbia, 828 West 10th Avenue, Vancouver, BC, Canada V5Z 1L8
| | | | | | | | | | | |
Collapse
|
30
|
Dong Z, Ferger B, Paterna JC, Vogel D, Furler S, Osinde M, Feldon J, Büeler H. Dopamine-dependent neurodegeneration in rats induced by viral vector-mediated overexpression of the parkin target protein, CDCrel-1. Proc Natl Acad Sci U S A 2003; 100:12438-43. [PMID: 14530399 PMCID: PMC218776 DOI: 10.1073/pnas.2132992100] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mutations in the parkin gene are linked to autosomal-recessive juvenile parkinsonism (AR-JP). Parkin functions as a ubiquitin protein ligase in the degradation of several proteins, including the neuron-specific septin CDCrel-1. AR-JP-associated parkin mutations inhibit ubiquitination and degradation of CDCrel-1 and other parkin target proteins. Here we show that recombinant adeno-associated virus-mediated CDCrel-1 gene transfer to the substantia nigra of rats results in a rapid onset (6-10 days) of nigral and striatal CDCrel-1 expression that is followed by a progressive loss of nigral dopaminergic neurons and a decline of the striatal dopamine levels. In contrast, neurons of the globus pallidus are spared from CDCrel-1 toxicity. Furthermore, CDCrel-1 inhibits the release of dopamine from stably-transfected PC12 cells, and pharmacological inhibition of tyrosine hydroxylase and dopamine synthesis in rats prevents CDCrel-1-induced nigral neurodegeneration. These results show that CDCrel-1 overexpression exerts dopamine-dependent neurotoxicity and suggest that inhibition of dopamine secretion by CDCrel-1 may contribute to the development of AR-JP.
Collapse
Affiliation(s)
- Zhizhong Dong
- Institute of Molecular Biology, University of Zurich, 8057 Zurich, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Yang H, Standifer KM, Sherry DM. Synaptic protein expression by regenerating adult photoreceptors. J Comp Neurol 2002; 443:275-88. [PMID: 11807837 DOI: 10.1002/cne.10116] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Regeneration of functionally normal synapses is required for functional recovery after degenerative central nervous system insults and requires proper expression and targeting of presynaptic proteins by regenerating neurons. The reconstitution of presynaptic terminals by regenerating adult neurons is poorly understood, however. We examined the intrinsic ability of regenerating adult retinal photoreceptors to reconstitute properly differentiated presynaptic terminals in the absence of target contact. The expression and localization of vesicle-associated membrane protein (VAMP), synaptic vesicle protein 2 (SV2), synaptophysin, synapsin I, and synaptosomal-associated protein of 25 kDa (SNAP-25) was assessed immunocytochemically. Photoreceptor terminals in the intact retina contain VAMP, SV2, synaptophysin, and SNAP-25, but not synapsin I. Isolated, regenerating adult photoreceptors intrinsically expressed the proper complement of synaptic vesicle proteins in the absence of target contact: VAMP, SV2, and synaptophysin were present at all stages of regenerative growth; synapsin I was never expressed. At early stages of regenerative growth, VAMP, SV2, and synaptophysin were diffusely localized in the cell, with prominent VAMP labeling distributed along the plasma membrane. SV2 and synaptophysin rapidly localized to regenerated terminals, but VAMP accumulated much more slowly, indicating that these proteins are trafficked independently. In contrast, labeling for SNAP-25, which is associated with the presynaptic plasma membrane, was undetectable in regenerating photoreceptors, suggesting that SNAP-25 expression is target-regulated. Thus, regenerating photoreceptors can intrinsically regulate the expression of the proper set of synaptic vesicle proteins. Proper expression of other presynaptic proteins, such as SNAP-25, and proper subcellular localization of synaptic proteins such as VAMP, however, may require extrinsic cues such as target contact.
Collapse
Affiliation(s)
- Haidong Yang
- College of Optometry, University of Houston, Houston, Texas 77204-2020, USA
| | | | | |
Collapse
|
32
|
Peng XR, Jia Z, Zhang Y, Ware J, Trimble WS. The septin CDCrel-1 is dispensable for normal development and neurotransmitter release. Mol Cell Biol 2002; 22:378-87. [PMID: 11739749 PMCID: PMC134223 DOI: 10.1128/mcb.22.1.378-387.2002] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Septins are GTPases required for the completion of cytokinesis in a variety of organisms, yet their role in this process is not known. Septins may have additional functions since the mammalian septin CDCrel-1 is predominantly expressed in the nervous system, a largely postmitotic tissue. While relatively little is known about the function of this protein, we have previously shown that it is involved in regulated secretion. In addition, the gene encoding this protein maps to a locus often deleted in velo-cardiofacial and DiGeorge syndromes, and CDCrel-1 has recently been shown to be a direct target of the E3 ubiquitin ligase activity of Parkin, a causative agent in autosomal recessive forms of Parkinson's disease. Here we show that CDCrel-1 expression rises at the time of synaptic maturation and that CDCrel-1 is present in a complex that includes the septins Nedd5 and CDC10. To investigate its function in the nervous system, we generated homozygotic CDCrel-1 null mice and showed that these mice appear normal with respect to synaptic properties and hippocampal neuron growth in vitro. Moreover, we found that while the expression of a number of synaptic proteins is not affected in the CDCrel-1 mutant mice, the expression of other septins is altered. Together, these data suggest that CDCrel-1 is not essential for neuronal development or function, and that changes in expression of other septins may account for its functional redundancy.
Collapse
Affiliation(s)
- Xiao-Rong Peng
- Programmes in Cell Biology. Brain and Behavior, Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|
33
|
Schmitz F. Immunological heterogeneity of synaptic and extrasynaptic forms of non-erythroid alpha-spectrin in the rat retina. Neurosci Lett 2001; 313:25-8. [PMID: 11684331 DOI: 10.1016/s0304-3940(01)02238-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
alpha-, beta- Spectrin is ubiquitously distributed in neuronal compartments, i.e. at the plasma membrane of neuronal cell bodies, axonal and dendritic processes, pre- and postsynaptic nerve terminals and around synaptic vesicles, "Brain Res. Bull. 50 (1999) 345". Ultrastructural analyses in the rat retina using the monoclonal antibody AA6, "Hear. Res. 43 (1990) 199", against non-erythroid alpha-spectrin, alphaSPII (spectrin nomenclature according to "Blood 81 (1993) 3173"), revealed that the antibody intensively labeled the cytoplasmic face of the plasma membrane in virtually all neuronal processes. However, no significant immunolabel was observed at the presynaptic plasma membrane, around synaptic vesicles, at presynaptic densities and synaptic ribbons. Therefore, synaptic non-erythroid alpha-spectrin differs immunologically from extrasynaptic non-erythroid alpha-spectrin. This heterogeneity might contribute to the generation of distinct retinal microdomains.
Collapse
Affiliation(s)
- F Schmitz
- Institute for Anatomy, Julius-Maximilians-University of Würzburg, Koellikerstrasse 6, 97070 Würzburg, Germany.
| |
Collapse
|
34
|
Beites CL, Peng XR, Trimble WS. Expression and analysis of properties of septin CDCrel-1 in exocytosis. Methods Enzymol 2001; 329:499-510. [PMID: 11210570 DOI: 10.1016/s0076-6879(01)29111-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- C L Beites
- Programme in Cell Biology, Hospital for Sick Children, Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5G 1X8
| | | | | |
Collapse
|
35
|
Abstract
Vesicle associated membrane protein (VAMP; also known as synaptobrevin) is a key component of the core complex needed for docking and fusion of synaptic vesicles with the presynaptic plasma membrane. Recent work indicates that the precise complement of presynaptic proteins associated with transmitter release and their isoforms vary among synapses, presumably conferring specific functional release properties. The retina contains two types of vesicular synapses with distinct morphologic, functional, and biochemical characteristics: ribbon and conventional synapses. Although the precise complement of presynaptic proteins is known to differ between conventional and ribbon synapses and among conventional synapses, the distribution of VAMP isoforms among retinal synapses has not been determined. The expression and localization of VAMP isoforms in the salamander retina, a major model system for studies of retinal circuitry, was examined by using immunocytochemical and immunoblotting methods. Both methods indicated that at least two VAMP isoforms were expressed in salamander retina. One isoform, recognized by an immunoglobulin M antibody that recognizes both mammalian VAMP-1 and VAMP-2, was associated with photoreceptor and bipolar cell terminals as well as many conventional synapses, and probably corresponds to mammalian VAMP-2. A different VAMP isoform associated with a subset of amacrine cells, was recognized only by antibodies directed against the N-terminus of mammalian VAMP-2. An antiserum directed against the N-terminus of mammalian VAMP-1 did not specifically recognize any salamander VAMPs in either immunocytochemical or immunoblotting experiments. Heterogeneous distribution of VAMP isoforms among conventional retinal synapses was confirmed by double labeling for synapsin I, a marker for conventional synapses. These studies indicate that VAMP isoforms are expressed heterogeneously among retinal synapses but cannot account for the differences in transmitter release characteristics at ribbon and conventional synapses. These results also corroborate previous studies in Xenopus indicating that the N-terminus of nonmammalian VAMP isoforms differs from their mammalian counterparts.
Collapse
Affiliation(s)
- D M Sherry
- College of Optometry, University of Houston, Houston, Texas 77004, USA.
| | | | | |
Collapse
|
36
|
Abstract
We have carried out a comparative immunohistochemical study on four members of the septin family, CDCrel-1, Septin6, CDC10, and H5, which are abundantly expressed in the adult mouse brain. We found that each septin showed overlapping but distinct distribution at the levels of light and electron microscopy. CDCrel-1 was abundant in inhibitory presynaptic terminals and associated with GABAergic vesicles in the thalamus, globus pallidus, and cerebellar nuclei. Septin6 was associated with synaptic vesicles in various brain regions, including glomeruli of the olfactory bulb. CDC10 was diffusely expressed in the brain and was localized beneath presynaptic membrane and astroglial processes. H5 was localized in the astroglial processes in some specific brain regions. The differential expression and subcellular localization of these septins indicates that a given neuron or glial cell expresses a specific set of septin monomers and that the resulting septin complexes with distinct compositions may play distinct roles in the brain.
Collapse
Affiliation(s)
- A Kinoshita
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | | | | |
Collapse
|
37
|
Abstract
PKA phosphorylations of tau may be an early event in the development of neurofibrillary pathology in Alzheimer's disease. Serines 214 and 409 of tau are highly phosphorylated in PHF-tau, but are not phosphorylated to any significant extent in normal adult human brain; both of these sites are phosphorylated in human fetal tissue. To further study this phenomenon, a developmental characterization of these phosphorylation sites relative to PKA, cAMP-dependent response binding element (CREB) and phosphorylated CREB was performed using samples from mouse brain. Immunoblot analysis using antibodies specific for phospho-serine 214 (CP-3) and phospho-serine 409 (PG-5) revealed a marked decrease in phosphorylation occurring at each of these sites between postnatal day 11 (P11) and P20. Immunoblots with TG-5, a pan-tau antibody, revealed uniform expression of tau during postnatal development, as well as a switch in isoform composition that is evident between P7 and P11. This switch in isoform composition just precedes the change in the extent of phosphorylation at serines 214 and 409, and occurs at a time when PKA phosphorylation of CREB is increasing.
Collapse
Affiliation(s)
- C A Andorfer
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | |
Collapse
|
38
|
Vannucci SJ, Clark RR, Koehler-Stec E, Li K, Smith CB, Davies P, Maher F, Simpson IA. Glucose transporter expression in brain: relationship to cerebral glucose utilization. Dev Neurosci 2000; 20:369-79. [PMID: 9778574 DOI: 10.1159/000017333] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Glucose is the principle energy source for mammalian brain. Delivery of glucose from the blood to the brain requires its transport across the endothelial cells of the blood-brain barrier and across the plasma membranes of neurons and glia, which is mediated by the facilitative glucose transporter proteins. The two primary glucose transporter isoforms which function in cerebral glucose metabolism are GLUT1 and GLUT3. GLUT1 is the primary transporter in the blood-brain barrier, choroid plexus, ependyma, and glia; GLUT3 is the neuronal glucose transporter. The levels of expression of both transporters are regulated in concert with metabolic demand and regional rates of cerebral glucose utilization. We present several experimental paradigms in which alterations in energetic demand and/or substrate supply affect glucose transporter expression. These include normal cerebral development in the rat, Alzheimer's disease, neuronal differentiation in vitro, and dehydration in the rat.
Collapse
Affiliation(s)
- S J Vannucci
- Department of Pediatrics, Milton S. Hershey Medical Center-Pennsylvania State University, Hershey, PA, USA
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Ishizawa K, Lin WL, Tiseo P, Honer WG, Davies P, Dickson DW. A qualitative and quantitative study of grumose degeneration in progressive supranuclear palsy. J Neuropathol Exp Neurol 2000; 59:513-24. [PMID: 10850864 DOI: 10.1093/jnen/59.6.513] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Grumose degeneration (GD) of the dentate nucleus is a common feature in progressive supranuclear palsy (PSP), but its pathogenesis has not been well studied, and its clinical significance remains unknown. This report describes a quantitative study of GD in 9 cases of PSP using image analysis with single- and double-immunolabeling, as well as histochemical stains for myelin and axons. GD was associated with demyelination, axonal loss, glial tau pathology, and microgliosis in regions juxtaposed to the dentate nucleus (DN). Specifically, demyelination and microgliosis were prominent in the superior cerebellar peduncle (SCP), dentate hilus, and cerebellar hemispheric white matter. Tau pathology and microgliosis were less prominent in the DN itself. The degree of myelin loss correlated with the tau burden in the SCP. GAP-43, which is a phosphoprotein known to be involved in axonal growth and sprouting, was decreased in the DN of PSP, and the degree of GAP-43 loss correlated with severity of GD. These results suggest that GD may be related to progressive pathology in the dentatorubrothalamic tract as well as the cerebellar hemispheric white matter, and that GD may be a consequence of concurrent degeneration in both output from and input to the DN. The results further suggest a possible role for oligodendroglial and myelin pathology in the pathogenesis of PSP.
Collapse
Affiliation(s)
- K Ishizawa
- Department of Pathology, Mayo Clinic Jacksonville, Florida 32224, USA
| | | | | | | | | | | |
Collapse
|
40
|
Shafit-Zagardo B, Davies P, Rockwood J, Kress Y, Lee SC. Novel microtubule-associated protein-2 isoform is expressed early in human oligodendrocyte maturation. Glia 2000. [DOI: 10.1002/(sici)1098-1136(20000201)29:3<233::aid-glia5>3.0.co;2-u] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
41
|
Shafit-Zagardo B, Kress Y, Zhao ML, Lee SC. A novel microtubule-associated protein-2 expressed in oligodendrocytes in multiple sclerosis lesions. J Neurochem 1999; 73:2531-7. [PMID: 10582615 DOI: 10.1046/j.1471-4159.1999.0732531.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Elucidation of the mechanisms involved in the regeneration of oligodendrocytes and remyelination is a central issue in multiple sclerosis (MS) research. We recently identified a novel alternatively spliced, developmentally regulated oligodendrocyte-specific protein designated microtubule-associated protein-2+13 [microtubule-associated protein-2 expressing exon 13 (MAP-2+13)]. MAP-2+13 is expressed in human fetal oligodendrocytes during process extension and myelination but is minimally expressed in normal mature CNS. To test the hypothesis that MAP-2+13 is reexpressed in regenerating oligodendrocytes in MS lesions, we examined the brains of MS patients for the expression of this protein. By immunocytochemistry using a series of monoclonal antibodies specific for MAP-2+13, we determined that MAP-2+13 expression was up-regulated in all 31 lesions from 10 different MS brains. MAP-2+13 was expressed in regenerating oligodendrocytes associated with demyelinated lesions, with the highest counts found in regions of extensive remyelination. By electron microscopy, MAP-2+13 was localized to oligodendrocytes engaged in remyelination, evident by their process extension and association with thinly myelinated (remyelinated) and demyelinated axons. These results suggest a hitherto unsuspected role for this microtubule-associated protein in oligodendrocyte function during development and myelin repair.
Collapse
Affiliation(s)
- B Shafit-Zagardo
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | |
Collapse
|
42
|
Galvin JE, Uryu K, Lee VM, Trojanowski JQ. Axon pathology in Parkinson's disease and Lewy body dementia hippocampus contains alpha-, beta-, and gamma-synuclein. Proc Natl Acad Sci U S A 1999; 96:13450-5. [PMID: 10557341 PMCID: PMC23968 DOI: 10.1073/pnas.96.23.13450] [Citation(s) in RCA: 335] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pathogenic alpha-synuclein (alphaS) gene mutations occur in rare familial Parkinson's disease (PD) kindreds, and wild-type alphaS is a major component of Lewy bodies (LBs) in sporadic PD, dementia with LBs (DLB), and the LB variant of Alzheimer's disease, but beta-synuclein (betaS) and gamma-synuclein (gammaS) have not yet been implicated in neurological disorders. Here we show that in PD and DLB, but not normal brains, antibodies to alphaS and betaS reveal novel presynaptic axon terminal pathology in the hippocampal dentate, hilar, and CA2/3 regions, whereas antibodies to gammaS detect previously unrecognized axonal spheroid-like lesions in the hippocampal dentate molecular layer. The aggregation of other synaptic proteins and synaptic vesicle-like structures in the alphaS- and betaS-labeled hilar dystrophic neurites suggests that synaptic dysfunction may result from these lesions. Our findings broaden the concept of neurodegenerative "synucleinopathies" by implicating betaS and gammaS, in addition to alphaS, in the onset/progression of PD and DLB.
Collapse
Affiliation(s)
- J E Galvin
- Department of Neurology, Medical College of Pennsylvania, Hahnemann University, 245 North 15th Street, Philadelphia, PA 19129, USA
| | | | | | | |
Collapse
|
43
|
Sutton KG, McRory JE, Guthrie H, Murphy TH, Snutch TP. P/Q-type calcium channels mediate the activity-dependent feedback of syntaxin-1A. Nature 1999; 401:800-4. [PMID: 10548106 DOI: 10.1038/44586] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spatial and temporal changes in intracellular calcium concentrations are critical for controlling gene expression in neurons. In many neurons, activity-dependent calcium influx through L-type channels stimulates transcription that depends on the transcription factor CREB by activating a calmodulin-dependent pathway. Here we show that selective influx of calcium through P/Q-type channels is responsible for activating expression of syntaxin-1A, a presynaptic protein that mediates vesicle docking, fusion and neurotransmitter release. The initial P/Q-type calcium signal is amplified by release of calcium from intracellular stores and acts through phosphorylation that is dependent on the calmodulin-dependent kinase CaM K II/IV, protein kinase A and mitogen-activated protein kinase kinase. Initiation of syntaxin-1A expression is rapid and short-lived, with syntaxin-1A ultimately interacting with the P/Q-type calcium channel to decrease channel availability. Our results define an activity-dependent feedback pathway that may regulate synaptic efficacy and function in the nervous system.
Collapse
Affiliation(s)
- K G Sutton
- Biotechnology Laboratory, Dept Psychiatry University of British Columbia, Vancouver, Canada
| | | | | | | | | |
Collapse
|
44
|
Raciborska DA, Charlton MP. Retention of cleaved synaptosome-associated protein of 25 kDa (SNAP-25) in neuromuscular junctions: a new hypothesis to explain persistence of botulinum A poisoning. Can J Physiol Pharmacol 1999. [DOI: 10.1139/y99-089] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Botulinum neurotoxins can block neurotransmitter release for several months. The molecular mechanism of these toxins' action is known, but the persistence of neuromuscular paralysis that they cause is unexplained. At frog neuromuscular junctions, application of botulinum toxin type A caused paralysis and reduced the C-terminus immunoreactivity of SNAP-25, but not that of the remaining N-terminus fragment. Botulinum toxin type C caused paralysis and reduced syntaxin immunoreactivity without affecting that of SNAP-25. Co-application of botulinum A and C reduced syntaxin immunoreactivity, and that of both C and N termini of SNAP-25. Application of hydroxylamine to de-palmitoylate SNAP-25 resulted in a slight reduction of the immunoreactivity of SNAP-25 N terminus, while it had no effect on immunoreactivity of botulinum A cleaved SNAP-25. In contrast, application of hydroxylamine to nerve terminals where syntaxin had been cleaved by botulinum C caused a considerable reduction in SNAP-25 N-terminus immunoreactivity. Hence the retention of immunoreactive SNAP-25 at the neuromuscular junction depends on its interactions with syntaxin and plasma membrane. Persistence of cleaved SNAP-25 in nerve terminals may prevent insertion of new SNAP-25 molecules, thereby contributing to the longevity of botulinum A effects.Key words: SNAP receptor, neurotoxin, dystonia, botulism, torticollis.
Collapse
|
45
|
Beites CL, Xie H, Bowser R, Trimble WS. The septin CDCrel-1 binds syntaxin and inhibits exocytosis. Nat Neurosci 1999; 2:434-9. [PMID: 10321247 DOI: 10.1038/8100] [Citation(s) in RCA: 285] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Septins are GTPases required for the completion of cytokinesis in diverse organisms, yet their roles in cytokinesis or other cellular processes remain unknown. Here we describe studies of a newly identified septin, CDCrel-1, which is predominantly expressed in the nervous system. This protein was associated with membrane fractions, and a significant fraction of the protein copurified and coprecipitated with synaptic vesicles. In detergent extracts, CDCrel-1 and another septin, Nedd5, immunoprecipitated with the SNARE protein syntaxin by directly binding to syntaxin via the SNARE interaction domain. Transfection of HIT-T15 cells with wild-type CDCrel-1 inhibited secretion, whereas GTPase dominant-negative mutants enhanced secretion. These data suggest that septins may regulate vesicle dynamics through interactions with syntaxin.
Collapse
Affiliation(s)
- C L Beites
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
46
|
Human Platelets Contain SNARE Proteins and a Sec1p Homologue That Interacts With Syntaxin 4 and Is Phosphorylated After Thrombin Activation: Implications for Platelet Secretion. Blood 1999. [DOI: 10.1182/blood.v93.8.2617.408k19_2617_2626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In response to thrombin and other extracellular activators, platelets secrete molecules from large intracellular vesicles (granules) to initiate thrombosis. Little is known about the molecular machinery responsible for vesicle docking and secretion in platelets and the linkage of that machinery to cell activation. We found that platelet membranes contain a full complement of interacting proteins—VAMP, SNAP-25, and syntaxin 4—that are necessary for vesicle docking and fusion with the plasma membrane. Platelets also contain an uncharacterized homologue of the Sec1p family that appears to regulate vesicle docking through its binding with a cognate syntaxin. This platelet Sec1 protein (PSP) bound to syntaxin 4 and thereby excluded the binding of SNAP-25 with syntaxin 4, an interaction critical to vesicle docking. As predicted by its sequence, PSP was detected predominantly in the platelet cytosol and was phosphorylated in vitro by protein kinase C (PKC), a secretion-linked kinase, incorporating 0.87 ± 0.11 mol of PO4 per mole of protein. PSP was also specifically phosphorylated in permeabilized platelets after cellular stimulation by phorbol esters or thrombin and this phosphorylation was blocked by the PKC inhibitor Ro-31-8220. Phosphorylation by PKC in vitro inhibited PSP from binding to syntaxin 4. Taken together, these studies indicate that platelets, like neurons and other cells capable of regulated secretion, contain a unique complement of interacting vesicle docking proteins and PSP, a putative regulator of vesicle docking. The PKC-dependent phosphorylation of PSP in activated platelets and its inhibitory effects on syntaxin 4 binding provide a novel functional link that may be important in coupling the processes of cell activation, intracellular signaling, and secretion.
Collapse
|
47
|
Human Platelets Contain SNARE Proteins and a Sec1p Homologue That Interacts With Syntaxin 4 and Is Phosphorylated After Thrombin Activation: Implications for Platelet Secretion. Blood 1999. [DOI: 10.1182/blood.v93.8.2617] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractIn response to thrombin and other extracellular activators, platelets secrete molecules from large intracellular vesicles (granules) to initiate thrombosis. Little is known about the molecular machinery responsible for vesicle docking and secretion in platelets and the linkage of that machinery to cell activation. We found that platelet membranes contain a full complement of interacting proteins—VAMP, SNAP-25, and syntaxin 4—that are necessary for vesicle docking and fusion with the plasma membrane. Platelets also contain an uncharacterized homologue of the Sec1p family that appears to regulate vesicle docking through its binding with a cognate syntaxin. This platelet Sec1 protein (PSP) bound to syntaxin 4 and thereby excluded the binding of SNAP-25 with syntaxin 4, an interaction critical to vesicle docking. As predicted by its sequence, PSP was detected predominantly in the platelet cytosol and was phosphorylated in vitro by protein kinase C (PKC), a secretion-linked kinase, incorporating 0.87 ± 0.11 mol of PO4 per mole of protein. PSP was also specifically phosphorylated in permeabilized platelets after cellular stimulation by phorbol esters or thrombin and this phosphorylation was blocked by the PKC inhibitor Ro-31-8220. Phosphorylation by PKC in vitro inhibited PSP from binding to syntaxin 4. Taken together, these studies indicate that platelets, like neurons and other cells capable of regulated secretion, contain a unique complement of interacting vesicle docking proteins and PSP, a putative regulator of vesicle docking. The PKC-dependent phosphorylation of PSP in activated platelets and its inhibitory effects on syntaxin 4 binding provide a novel functional link that may be important in coupling the processes of cell activation, intracellular signaling, and secretion.
Collapse
|
48
|
Caltagarone J, Rhodes J, Honer WG, Bowser R. Localization of a novel septin protein, hCDCrel-1, in neurons of human brain. Neuroreport 1998; 9:2907-12. [PMID: 9760144 DOI: 10.1097/00001756-199808240-00042] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Synaptic function is critical for cell-cell communication and the characterization of proteins that function during vesicle formation, transport and fusion events will yield further insight into the mechanisms of synaptic transmission. We have cloned and characterized a gene product expressed in human brain called hCDCrel-1. This protein is a new member of the septin family of gene products that functions during cytokinesis in lower eukaryotes. In this study we characterize the expression of the hCDCrel-1 gene and localize the hCDCrel-1 protein to neurons in adult human brain. hCDCrel-1 co-purifies with SNAP-25 and synaptophysin marked synaptosomes, suggesting a novel function for this gene family in the brain. Our data indicate that members of the septin family of proteins may function in synaptic vesicle transport, fusion or recycling events in the human brain.
Collapse
Affiliation(s)
- J Caltagarone
- Department of Pathology, University of Pittsburgh School of Medicine, PA 15261, USA
| | | | | | | |
Collapse
|
49
|
Raciborska DA, Trimble WS, Charlton MP. Presynaptic protein interactions in vivo: evidence from botulinum A, C, D and E action at frog neuromuscular junction. Eur J Neurosci 1998; 10:2617-28. [PMID: 9767392 DOI: 10.1046/j.1460-9568.1998.00270.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study examines the paralytic action of botulinum neurotoxins at their natural target, the neuromuscular junction. We asked whether syntaxin, synaptosome-associated protein of 25 kDa (SNAP-25) and vesicle-associated membrane protein (VAMP/synaptobrevin), the proteins proteolysed by botulinum, are susceptible to cleavage in frog nerve terminals, and whether they form complexes in vivo. In control terminals, the three SNAREs were distributed in broad bands at 1 micrometer intervals, at sites consistent with presynaptic Ca2+ channels. Within 3 h, botulinum A, C, D and E (BoNT/A/C/D/E) blocked nerve-evoked muscle contractions but their effects on substrate immunoreactivity varied. The effect of BoNT/A on either C-terminus or N-terminus immunoreactivity of SNAP-25 was undetectable after 3-h incubation, although C-terminus immunoreactivity was reduced after 24 h; N-terminus immunoreactivity was not affected even after 36 h. BoNT/E reduced C-terminus immunoreactivity of SNAP-25 1.5 h after toxin application when transmitter release was blocked, but required 24 h to reduce N-terminus immunoreactivity. BoNT/C reduced syntaxin immunoreactivity after 24-h incubation but did not affect SNAP-25. BoNT/D reduced VAMP immunoreactivity at 3 h while it increased SNAP-25 C-terminal staining fourfold. BoNT/A and BoNT/C applied together for 24 h reduced syntaxin immunoreactivity and that of both C- and N-terminus of SNAP-25, indicating that retention of SNAP-25 N-terminus after cleavage by BoNT/A depended on intact syntaxin. Therefore, we infer that SNAP-25 interacts with VAMP and with syntaxin in vivo. Neurotoxin action abolished only 40-60% of SNAP-25, VAMP or syntaxin immunoreactivity suggesting that distinct pools of these proteins, not immediately involved in triggered exocytosis, are resistant to proteolysis.
Collapse
Affiliation(s)
- D A Raciborska
- University of Toronto, Department of Physiology, Medical Sciences Building, Toronto, Ontario, Canada, M5S 1A8
| | | | | |
Collapse
|
50
|
Abstract
To further characterize the molecular mechanisms of platelet function, we have sought to identify some of the proteins that mediate the secretory events of the platelet release reaction. We report that platelets contain the general elements of the membrane transport apparatus: N-ethylmaleimide sensitive fusion protein (NSF ), p115/transcytosis-associated protein (p115/TAP), and the soluble NSF attachment proteins (α- and, γ-SNAP). The cDNAs encoding two of these proteins, α- and γ-SNAP, have been cloned from a human platelet-derived cDNA library. Platelet membrane extracts possess SNAPreceptor (SNARE) activity, suggesting that the class of proteins (SNAREs) proposed to provide the specificity for vesicle docking and membrane fusion are present in platelets. To identify these proteins, we have used specific antibodies against known SNAREs to probe platelet extracts. Syntaxin 2 and 4 can be readily detected in platelet membrane preparations and are shown to participate in 20 S complex formation. Syntaxin 1, 3, and 5 could not be detected. Other known SNARE and SNARE-associated proteins such as vesicle-associated membrane protein (VAMP)/synaptobrevin 2, SNAP-25, synaptophysin, or synaptotagmin I could not be immunochemically detected in platelet membrane preparations. The presence of both the general transport proteins (NSF and SNAPs) and specific transport proteins (syntaxin 2 and 4) indicates that platelet exocytosis uses a molecular mechanism similar to other secretory cells such as neurons. However, the subcellular concentrations of these proteins suggest that, unlike neuronal secretion, granule-to plasma membrane docking may be the limiting step in platelet exocytosis.
Collapse
|