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Oshima T, Kater MSJ, Huffels CFM, Wesseling EM, Middeldorp J, Hol EM, Verheijen MHG, Smit AB, Boddeke EWGM, Eggen BJL. Early amyloid-induced changes in microglia gene expression in male APP/PS1 mice. J Neurosci Res 2024; 102:e25295. [PMID: 38515329 DOI: 10.1002/jnr.25295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 12/04/2023] [Accepted: 01/12/2024] [Indexed: 03/23/2024]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common cause of dementia, characterized by deposition of extracellular amyloid-beta (Aβ) aggregates and intraneuronal hyperphosphorylated Tau. Many AD risk genes, identified in genome-wide association studies (GWAS), are expressed in microglia, the innate immune cells of the central nervous system. Specific subtypes of microglia emerged in relation to AD pathology, such as disease-associated microglia (DAMs), which increased in number with age in amyloid mouse models and in human AD cases. However, the initial transcriptional changes in these microglia in response to amyloid are still unknown. Here, to determine early changes in microglia gene expression, hippocampal microglia from male APPswe/PS1dE9 (APP/PS1) mice and wild-type littermates were isolated and analyzed by RNA sequencing (RNA-seq). By bulk RNA-seq, transcriptomic changes were detected in hippocampal microglia from 6-months-old APP/PS1 mice. By performing single-cell RNA-seq of CD11c-positive and negative microglia from 6-months-old APP/PS1 mice and analysis of the transcriptional trajectory from homeostatic to CD11c-positive microglia, we identified a set of genes that potentially reflect the initial response of microglia to Aβ.
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Affiliation(s)
- Takuya Oshima
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Mandy S J Kater
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Christiaan F M Huffels
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Evelyn M Wesseling
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jinte Middeldorp
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
- Department of Neurobiology & Aging, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erik W G M Boddeke
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Bart J L Eggen
- Department of Biomedical Sciences, Section Molecular Neurobiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Oppong-Gyebi A, Metzger D, Doan T, Han J, Vann PH, Yockey RA, Sumien N, Schreihofer DA. Long-term hypogonadism diminishes the neuroprotective effects of dietary genistein in young adult ovariectomized rats after transient focal ischemia. J Neurosci Res 2021; 100:598-619. [PMID: 34713481 DOI: 10.1002/jnr.24981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 08/19/2021] [Accepted: 09/25/2021] [Indexed: 02/06/2023]
Abstract
Increasing age disproportionately increases the risk of stroke among women compared to men of similar age, especially after menopause. One of the reasons for this observation is a sharp drop in circulating estrogens. However, the timing of initiation of estrogen replacement after menopause is associated with mixed beneficial and detrimental effects, hence contributing to widespread mistrust of estrogen use. Agents including soy isoflavones are being assessed as viable alternatives to estrogen therapy. In this study, we hypothesized that the neuroprotective effects of genistein, a soy isoflavone are less sensitive to the length of hypogonadism in young adult ovariectomized rats following cerebral ischemia. We expected that long-term hypogonadism will worsen motor and cognitive function, increase post-stroke inflammation with no effect on the neuroprotection of genistein. We compared the effect of treatment with dietary genistein (GEN) on short-term (2 weeks) and long-term hypogonadism (12 weeks) in young adult ovariectomized Sprague-Dawley rats on sensorimotor function, cognition and inflammation after focal ischemia. Dorsal Silastic implant of 17β-estradiol (E2) was used as a control for hormone therapy. Long-term hypogonadism stroked rats performed worse than the short-term hypogonadism stroked rats on the motor and cognitive function tests. GEN did not improve neurological assessment and motor learning after either short-term or long-term hypogonadism. GEN improved cognitive flexibility after short-term hypogonadism but not after the long-term. Both GEN and E2 reduced tissue loss after short-term hypogonadism and reduced GFAP expression at the contralateral side of ischemia after long-term hypogonadism. The length of hypogonadism may differentially influence the neuroprotective effects of both GEN and E2 on the motor and cognitive functions in young adult rats.
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Affiliation(s)
- Anthony Oppong-Gyebi
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.,Center for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Daniel Metzger
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.,Center for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Trinh Doan
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Jordan Han
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Phillip H Vann
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.,Center for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - R Andrew Yockey
- Department of Biostatistics and Epidemiology, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Nathalie Sumien
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.,Center for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Derek A Schreihofer
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.,Center for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Luque M, Schrott-Fischer A, Dudas J, Pechriggl E, Brenner E, Rask-Andersen H, Liu W, Glueckert R. HCN channels in the mammalian cochlea: Expression pattern, subcellular location, and age-dependent changes. J Neurosci Res 2020; 99:699-728. [PMID: 33181864 PMCID: PMC7839784 DOI: 10.1002/jnr.24754] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/03/2023]
Abstract
Neuronal diversity in the cochlea is largely determined by ion channels. Among voltage‐gated channels, hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels open with hyperpolarization and depolarize the cell until the resting membrane potential. The functions for hearing are not well elucidated and knowledge about localization is controversial. We created a detailed map of subcellular location and co‐expression of all four HCN subunits across different mammalian species including CBA/J, C57Bl/6N, Ly5.1 mice, guinea pigs, cats, and human subjects. We correlated age‐related hearing deterioration in CBA/J and C57Bl/6N with expression levels of HCN1, −2, and −4 in individual auditory neurons from the same cohort. Spatiotemporal expression during murine postnatal development exposed HCN2 and HCN4 involvement in a critical phase of hair cell innervation. The huge diversity of subunit composition, but lack of relevant heteromeric pairing along the perisomatic membrane and axon initial segments, highlighted an active role for auditory neurons. Neuron clusters were found to be the hot spots of HCN1, −2, and −4 immunostaining. HCN channels were also located in afferent and efferent fibers of the sensory epithelium. Age‐related changes on HCN subtype expression were not uniform among mice and could not be directly correlated with audiometric data. The oldest mice groups revealed HCN channel up‐ or downregulation, depending on the mouse strain. The unexpected involvement of HCN channels in outer hair cell function where HCN3 overlaps prestin location emphasized the importance for auditory function. A better understanding may open up new possibilities to tune neuronal responses evoked through electrical stimulation by cochlear implants.
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Affiliation(s)
- Maria Luque
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Jozsef Dudas
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elisabeth Pechriggl
- Department of Anatomy, Histology & Embryology, Division of Clinical & Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria
| | - Erich Brenner
- Department of Anatomy, Histology & Embryology, Division of Clinical & Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Wei Liu
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Rudolf Glueckert
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria.,Tirol Kliniken, University Clinics Innsbruck, Innsbruck, Austria
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Fazekas EA, Morvai B, Zachar G, Dóra F, Székely T, Pogány Á, Dobolyi A. Neuronal activation in zebra finch parents associated with reintroduction of nestlings. J Comp Neurol 2019; 528:363-379. [PMID: 31423585 DOI: 10.1002/cne.24761] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 08/14/2019] [Accepted: 08/14/2019] [Indexed: 12/23/2022]
Abstract
Recent studies of the brain mechanisms of parental behaviors have mainly focused on rodents. Using other vertebrate taxa, such as birds, can contribute to a more comprehensive, evolutionary view. In the present study, we investigated a passerine songbird, the zebra finch (Taeniopygia guttata), with a biparental caring system. Parenting-related neuronal activation was induced by first temporarily removing the nestlings, and then, either reuniting the focal male or female parent with the nestlings (parental group) or not (control group). To identify activated neurons, the immediate early gene product, Fos protein, was labeled. Both parents showed an increased level of parental behavior following reunion with the nestlings, and no sexual dimorphism occurred in the neuronal activation pattern. Offspring-induced parental behavior-related neuronal activation was found in the preoptic, ventromedial (VMH), paraventricular hypothalamic nuclei, and in the bed nucleus of the stria terminalis. In addition, the number of Fos-immunoreactive (Fos-ir) neurons in the nucleus accumbens predicted the frequency of the feeding of the nestlings. No difference was found in Fos expression when the effect of isolation or the presence of the mate was examined. Thus, our study identified a number of nuclei involved in parental care in birds and suggests similar regulatory mechanisms in caring females and males. The activated brain regions show similarities to rodents, while a generally lower number of brain regions were activated in the zebra finch. Furthermore, future studies are necessary to establish the role of the apparently avian-specific neuronal activation in the VMH of zebra finch parents.
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Affiliation(s)
- Emese A Fazekas
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungary Hungarian Academy of Sciences and Eötvös Loránd University, Budapest, Hungary.,Department of Ethology, Eötvös Loránd University, Budapest, Hungary
| | - Boglárka Morvai
- Department of Ethology, Eötvös Loránd University, Budapest, Hungary
| | - Gergely Zachar
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Fanni Dóra
- SE-NAP-Human Brain Tissue Bank Microdissection Laboratory and Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Tamás Székely
- Milner Center for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Ákos Pogány
- Department of Ethology, Eötvös Loránd University, Budapest, Hungary
| | - Arpád Dobolyi
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungary Hungarian Academy of Sciences and Eötvös Loránd University, Budapest, Hungary
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Ainani H, El Bousmaki N, Poirel VJ, Achaâban MR, Ouassat M, Piro M, Klosen P, Simonneaux V, El Allali K. The dromedary camel displays annual variation in hypothalamic kisspeptin and Arg-Phe-amide-related peptide-3 according to sex, season, and breeding activity. J Comp Neurol 2019; 528:32-47. [PMID: 31251823 DOI: 10.1002/cne.24736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 01/25/2023]
Abstract
The dromedary camel (Camelus dromedarius) is a desert mammal whose cycles in reproductive activity ensure that the offspring's birth and weaning coincide with periods of abundant food resources and favorable climate conditions. In this study, we assessed whether kisspeptin (Kp) and arginine-phenylalanine (RF)-amide related peptide-3 (RFRP-3), two hypothalamic peptides known to regulate the mammalian hypothalamo-pituitary gonadal axis, may be involved in the seasonal control of camel's reproduction. Using specific antibodies and riboprobes, we found that Kp neurons are present in the preoptic area (POA), suprachiasmatic (SCN), and arcuate (ARC) nuclei, and that RFRP-3 neurons are present in the paraventricular (PVN), dorsomedial (DMH), and ventromedial (VMH) hypothalamic nuclei. Kp fibers are found in various hypothalamic areas, notably the POA, SCN, PVN, DMH, VMH, supraoptic nucleus, and the ventral and dorsal premammillary nucleus. RFRP-3 fibers are found in the POA, SCN, PVN, DMH, VMH, and ARC. POA and ARC Kp neurons and DMH RFRP-3 neurons display sexual dimorphism with more neurons in female than in male. Both neuronal populations display opposed seasonal variations with more Kp neurons and less RFRP-3 neurons during the breeding (December-January) than the nonbreeding (July-August) season. This study is the first describing Kp and RFRP-3 in the camel's brain with, during the winter period lower RFRP-3 expression and higher Kp expression possibly responsible for the HPG axis activation. Altogether, our data indicate the involvement of both Kp and RFRP-3 in the seasonal control of the dromedary camel's breeding activity.
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Affiliation(s)
- Hassan Ainani
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco.,Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Najlae El Bousmaki
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Vincent-Joseph Poirel
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Mohamed Rachid Achaâban
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Mohammed Ouassat
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Mohammed Piro
- Medicine and Surgical Unit of Domestic animals, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Paul Klosen
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Valérie Simonneaux
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Khalid El Allali
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
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Ohgomori T, Jinno S. The expression of keratan sulfate reveals a unique subset of microglia in the mouse hippocampus after pilocarpine-induced status epileptics. J Comp Neurol 2019; 528:14-31. [PMID: 31237692 DOI: 10.1002/cne.24734] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/03/2019] [Accepted: 06/18/2019] [Indexed: 12/22/2022]
Abstract
Induction of keratan sulfate in microglia has been found in several animal models of neurological disorders. However, the significance of keratan sulfate-expressing microglia is not fully understood. To address this issue, we analyzed the characteristics of microglia labeled by the 5D4 epitope, a marker of high-sulfated keratan sulfate, in the mouse hippocampus during the latent period after pilocarpine-induced status epilepticus (SE). Only 5D4-negative (5D4- ) microglia were found in the CA1 region of vehicle-treated controls and pilocarpine-treated mice at 1 day after SE onset. A few 5D4+ microglia appeared in the strata oriens and radiatum at 5 days post-SE, and they were distributed into the stratum pyramidale at 14 days post-SE. The expressions of genes related to both anti- and pro-inflammatory cytokines were higher in 5D4+ cells than in 5D4- cells at 5 but not 14 days post-SE. The expressions of genes related to phagocytosis were higher in 5D4+ cells than in 5D4- cells throughout the latent period. The phagocytic activity of microglia, as measured by engulfment of the zymosan bioparticles, was higher in 5D4+ cells than in 5D4- cells. The contact ratios between excitatory synaptic boutons and microglia were also higher in 5D4+ cells than in 5D4- cells at 5 and 14 days post-SE. The excitatory/inhibitory ratios of synaptic boutons within the microglial domain were lower in 5D4+ cells than in 5D4- cells at 14 days post-SE. Our findings indicate that 5D4+ microglia may play some role in epileptogenesis via pruning of excitatory synapses during the latent period after SE.
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Affiliation(s)
- Tomohiro Ohgomori
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shozo Jinno
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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7
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Falcone C, Wolf-Ochoa M, Amina S, Hong T, Vakilzadeh G, Hopkins WD, Hof PR, Sherwood CC, Manger PR, Noctor SC, Martínez-Cerdeño V. Cortical interlaminar astrocytes across the therian mammal radiation. J Comp Neurol 2019; 527:1654-1674. [PMID: 30552685 DOI: 10.1002/cne.24605] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 01/21/2023]
Abstract
Interlaminar astrocytes (ILA) in the cerebral cortex possess a soma in layer I and extend an interlaminar process that runs perpendicular to the pia into deeper cortical layers. We examined cerebral cortex from 46 species that encompassed most orders of therian mammalians, including 22 primate species. We described two distinct cell types with interlaminar processes that have been referred to as ILA, that we termed pial ILA and supial ILA. ILA subtypes differ in somatic morphology, position in layer I, and presence across species. We further described rudimentary ILA that have short GFAP+ processes that do not exit layer I, and "typical" ILA with longer GFAP+ processes that exit layer I. Pial ILA were present in all mammalian species analyzed, with typical ILA observed in Primates, Scandentia, Chiroptera, Carnivora, Artiodactyla, Hyracoidea, and Proboscidea. Subpial ILA were absent in Marsupialia, and typical subpial ILA were only found in Primate. We focused on the properties of pial ILA by investigating the molecular properties of pial ILA and confirming their astrocytic nature. We found that while the density of pial ILA somata only varied slightly, the complexity of ILA processes varied greatly across species. Primates, specifically bonobo, chimpanzee, orangutan, and human, exhibited pial ILA with the highest complexity. We showed that interlaminar processes contact neurons, pia, and capillaries, suggesting a potential role for ILA in the blood-brain barrier and facilitating communication among cortical neurons, astrocytes, capillaries, meninges, and cerebrospinal fluid.
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Affiliation(s)
- Carmen Falcone
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Marisol Wolf-Ochoa
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Sarwat Amina
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, Sacramento, California.,UC Davis Medical Center, MIND Institute, Sacramento, California
| | - Tiffany Hong
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Gelareh Vakilzadeh
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, Sacramento, California
| | - William D Hopkins
- Neuroscience Institute and Language Research Center, Georgia State University, Atlanta, Georgia
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Stephen C Noctor
- UC Davis Medical Center, MIND Institute, Sacramento, California.,Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine, Sacramento, California
| | - Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, Sacramento, California.,UC Davis Medical Center, MIND Institute, Sacramento, California
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Senthilkumaran M, Bobrovskaya L, Verberne AJM, Llewellyn-Smith IJ. Insulin-responsive autonomic neurons in rat medulla oblongata. J Comp Neurol 2018; 526:2665-2682. [PMID: 30136719 DOI: 10.1002/cne.24523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 08/12/2018] [Accepted: 08/15/2018] [Indexed: 11/11/2022]
Abstract
Low blood glucose activates brainstem adrenergic and cholinergic neurons, driving adrenaline secretion from the adrenal medulla and glucagon release from the pancreas. Despite their roles in maintaining glucose homeostasis, the distributions of insulin-responsive adrenergic and cholinergic neurons in the medulla are unknown. We fasted rats overnight and gave them insulin (10 U/kg i.p.) or saline after 2 weeks of handling. Blood samples were collected before injection and before perfusion at 90 min. We immunoperoxidase-stained transverse sections of perfused medulla to show Fos plus either phenylethanolamine N-methyltransferase (PNMT) or choline acetyltransferase (ChAT). Insulin injection lowered blood glucose from 4.9 ± 0.3 mmol/L to 1.7 ± 0.2 mmol/L (mean ± SEM; n = 6); saline injection had no effect. In insulin-treated rats, many PNMT-immunoreactive C1 neurons had Fos-immunoreactive nuclei, with the proportion of activated neurons being highest in the caudal part of the C1 column. In the rostral ventrolateral medulla, 33.3% ± 1.4% (n = 8) of C1 neurons were Fos-positive. Insulin also induced Fos in 47.2% ± 2.0% (n = 5) of dorsal medullary C3 neurons and in some C2 neurons. In the dorsal motor nucleus of the vagus (DMV), insulin evoked Fos in many ChAT-positive neurons. Activated neurons were concentrated in the medial and middle regions of the DMV beneath and just rostral to the area postrema. In control rats, very few C1, C2, or C3 neurons and no DMV neurons were Fos-positive. The high numbers of PNMT-immunoreactive and ChAT-immunoreactive neurons that express Fos after insulin treatment reinforce the importance of these neurons in the central response to a decrease in glucose bioavailability.
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Affiliation(s)
- M Senthilkumaran
- Cardiovascular Medicine, Human Physiology and Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia.,School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - L Bobrovskaya
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - A J M Verberne
- Clinical Pharmacology and Therapeutics Unit, Department of Medicine-Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - I J Llewellyn-Smith
- Cardiovascular Medicine, Human Physiology and Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
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