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Dirr EW, Jiracek LG, Baekey DM, J Martyniuk C, Otto KJ, Zubcevic J. Subdiaphragmatic vagal nerve stimulation attenuates the development of hypertension and alters nucleus of the solitary tract transcriptional networks in the spontaneously hypertensive rat. Physiol Genomics 2023; 55:606-617. [PMID: 37746712 PMCID: PMC11178265 DOI: 10.1152/physiolgenomics.00016.2023] [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: 03/13/2023] [Revised: 08/18/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023] Open
Abstract
Augmented vagal signaling may be therapeutic in hypertension. Most studies to date have used stimulation of the cervical vagal branches. Here, we investigated the effects of chronic intermittent electric stimulation of the ventral subdiaphragmatic vagal nerve branch (sdVNS) on long-term blood pressure, immune markers, and gut microbiota in the spontaneously hypertensive rat (SHR), a rodent model of hypertension characterized by vagal dysfunction, gut dysbiosis, and low-grade inflammation. We evaluated the effects of sdVNS on transcriptional networks in the nucleus of the solitary tract (NTS), a major cardioregulatory brain region with direct gut vagal projections. Male juvenile SHRs were implanted with radiotelemetry transmitters and vagal nerve cuffs for chronic intermittent electric sdVNS, applied three times per day for 7 consecutive weeks followed by 1 wk of no stimulation. Blood pressure was measured once a week using telemetry in the sdVNS group as well as age-matched sham-stimulated SHR controls. At the endpoint, colonic and circulating inflammatory markers, corticosterone, and circulating catecholamines were investigated. Bacterial 16 s sequencing measured gut bacterial abundance and composition. RNA sequencing evaluated the effects of sdVNS on transcriptional networks in the NTS. SHRs that received sdVNS exhibited attenuated development of hypertension compared with sham animals. No changes in peripheral inflammatory markers, corticosterone, or catecholamines and no major differences in gut bacterial diversity and composition were observed following sdVNS, apart from decreased abundance of Defluviitaleaceale bacterium detected in sdVNS SHRs compared with sham animals. RNA sequencing revealed significant sdVNS-dependent modulation of select NTS transcriptional networks, including catecholaminergic and corticosteroid networks.NEW & NOTEWORTHY We show that stimulation of the ventral subdiaphragmatic vagal nerve branch may be a promising potential approach to treating hypertension. The data are especially encouraging given that rodents received only 30 min per day of intermittent stimulation therapy and in view of the potential of long-term blood pressure effects that are not stimulus-locked.
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Affiliation(s)
- Elliott W Dirr
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio, United States
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States
| | - Ladan G Jiracek
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States
| | - David M Baekey
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States
| | - Christopher J Martyniuk
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States
| | - Kevin J Otto
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States
- Department of Neurology, University of Florida, Gainesville, Florida, United States
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, United States
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, United States
| | - Jasenka Zubcevic
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio, United States
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Bakina O, Kettenmann H, Nolte C. Microglia form satellites with different neuronal subtypes in the adult murine central nervous system. J Neurosci Res 2022; 100:1105-1122. [PMID: 35213755 DOI: 10.1002/jnr.25026] [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: 04/23/2021] [Revised: 12/21/2021] [Accepted: 01/07/2022] [Indexed: 11/12/2022]
Abstract
Microglia are the innate immune cells of the central nervous system (CNS). In the adult uncompromised CNS, they have a highly ramified morphology and continuously extend and retract their processes. A subpopulation of microglial cells forms close soma-to-soma contacts with neurons and have been termed satellite microglia, yet the role of such interaction is largely unknown. Here, we analyzed the distribution of satellite microglia in different areas of the CNS of adult male mice applying transgenic- and immunolabeling of neuronal subtypes and microglia followed by three-dimensional imaging analysis. We quantified satellite microglia associated with GABAergic and glutamatergic neurons in the somatosensory cortex, striatum, and thalamus; with dopaminergic and serotonergic neurons in the basal forebrain and raphe nucleus, respectively; and with cerebellar Purkinje cell neurons. Satellite microglia in the retina were assessed qualitatively. Microglia form satellites with all neuronal subtypes studied, whereas a preference for a specific neuron subtype was not found. The occurrence and frequency of satellite microglia is determined by the histo-architectural organization of the brain area and the densities of neuronal somata therein.
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Affiliation(s)
- Olga Bakina
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Helmut Kettenmann
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Christiane Nolte
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
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Cohen EM, Farnham MMJ, Kakall Z, Kim SJ, Nedoboy PE, Pilowsky PM. Glia and central cardiorespiratory pathology. Auton Neurosci 2018; 214:24-34. [PMID: 30172674 DOI: 10.1016/j.autneu.2018.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 08/22/2018] [Accepted: 08/22/2018] [Indexed: 01/08/2023]
Abstract
Respiration and blood pressure are primarily controlled by somatic and autonomic motor neurones, respectively. Central cardiorespiratory control is critical in moment-to-moment survival, but it also has a role in the development and maintenance of chronic pathological conditions such as hypertension. The glial cells of the brain are non-neuronal cells with metabolic, immune, and developmental functions. Recent evidence shows that glia play an active role in supporting and regulating the neuronal circuitry which drives the cardiorespiratory system. Here we will review the activities of two key types of glial cell, microglia and astrocytes, in assisting normal central cardiorespiratory control and in pathology.
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Affiliation(s)
- E Myfanwy Cohen
- The Heart Research Institute, Sydney, New South Wales 2042, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Melissa M J Farnham
- The Heart Research Institute, Sydney, New South Wales 2042, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Zohra Kakall
- The Heart Research Institute, Sydney, New South Wales 2042, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Seung Jae Kim
- The Heart Research Institute, Sydney, New South Wales 2042, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Polina E Nedoboy
- The Heart Research Institute, Sydney, New South Wales 2042, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Paul M Pilowsky
- The Heart Research Institute, Sydney, New South Wales 2042, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia.
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Mileva GR, Moyes C, Syed S, Bielajew C. Strain Differences and Effects of Environmental Manipulation on Astrocytes (Glial Fibrillary Acidic Protein), Glucocorticoid Receptor, and Microglia (Iba1) Immunoreactivity between Wistar-Kyoto and Wistar Females. Neuropsychobiology 2018; 75:1-11. [PMID: 28700991 DOI: 10.1159/000476035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 04/18/2017] [Indexed: 01/04/2023]
Abstract
BACKGROUND Depression is often associated with an increase in hypothalamic-pituitary-adrenal (HPA) axis reactivity and immune response. To investigate this relationship, we examined the consequences of environmental manipulation on the neural correlates of the HPA axis and immune response in an animal model of depression, the Wistar-Kyoto (WKY) rat. Additionally, female animals are often overlooked in preclinical research because of the hormone fluctuations inherent in the estrous cycle. METHODS Female rats were randomly assigned to 1 of 3 environments for 30 days: (1) environmental enrichment (EE), (2) standard housing (SH), and (3) isolated housing (IH). Immunoreactivity of astrocytes (glial fibrillary acidic protein [GFAP]), glucocorticoid receptors (GRs), and microglia (Iba1) in the hippocampus and amygdala were measured using immunohistochemistry. RESULTS WKY animals had significantly more GR staining area and Iba1 staining intensity and area in the CA1 of the hippocampus. In enriched Wistar rats, GFAP staining intensity and area were greater in the CA1. A trend towards a greater percent of area stained with GR was found in WKY animals as compared to that of the Wistar animals. This was due to WKY females in EE having significantly higher GR staining intensity and area in the amygdala as compared to that of animals in SH. DISCUSSION These strain differences lend support to the use of WKY animals as an animal model of depression. Furthermore, due to the effects of EE on GFAP and GR staining in WKY females, we suggest that EE can be used as an intervention to potentially alleviate the negative effects of depression.
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Affiliation(s)
- Guergana R Mileva
- University of Ottawa, School of Psychology, Behavioural Neuroscience Group, Ottawa, ON, Canada
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Bhandare AM, Kapoor K, Powell KL, Braine E, Casillas-Espinosa P, O'Brien TJ, Farnham MM, Pilowsky PM. Inhibition of microglial activation with minocycline at the intrathecal level attenuates sympathoexcitatory and proarrhythmogenic changes in rats with chronic temporal lobe epilepsy. Neuroscience 2017; 350:23-38. [DOI: 10.1016/j.neuroscience.2017.03.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/02/2017] [Accepted: 03/07/2017] [Indexed: 12/19/2022]
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Stokes JA, Arbogast TE, Moya EA, Fu Z, Powell FL. Minocycline blocks glial cell activation and ventilatory acclimatization to hypoxia. J Neurophysiol 2017; 117:1625-1635. [PMID: 28100653 DOI: 10.1152/jn.00525.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 01/14/2023] Open
Abstract
Ventilatory acclimatization to hypoxia (VAH) is the time-dependent increase in ventilation, which persists upon return to normoxia and involves plasticity in both central nervous system respiratory centers and peripheral chemoreceptors. We investigated the role of glial cells in VAH in male Sprague-Dawley rats using minocycline, an antibiotic that inhibits microglia activation and has anti-inflammatory properties, and barometric pressure plethysmography to measure ventilation. Rats received either minocycline (45mg/kg ip daily) or saline beginning 1 day before and during 7 days of chronic hypoxia (CH, PiO2 = 70 Torr). Minocycline had no effect on normoxic control rats or the hypercapnic ventilatory response in CH rats, but minocycline significantly (P < 0.001) decreased ventilation during acute hypoxia in CH rats. However, minocycline administration during only the last 3 days of CH did not reverse VAH. Microglia and astrocyte activation in the nucleus tractus solitarius was quantified from 30 min to 7 days of CH. Microglia showed an active morphology (shorter and fewer branches) after 1 h of hypoxia and returned to the control state (longer filaments and extensive branching) after 4 h of CH. Astrocytes increased glial fibrillary acidic protein antibody immunofluorescent intensity, indicating activation, at both 4 and 24 h of CH. Minocycline had no effect on glia in normoxia but significantly decreased microglia activation at 1 h of CH and astrocyte activation at 24 h of CH. These results support a role for glial cells, providing an early signal for the induction but not maintenance of neural plasticity underlying ventilatory acclimatization to hypoxia.NEW & NOTEWORTHY The signals for neural plasticity in medullary respiratory centers underlying ventilatory acclimatization to chronic hypoxia are unknown. We show that chronic hypoxia activates microglia and subsequently astrocytes. Minocycline, an antibiotic that blocks microglial activation and has anti-inflammatory properties, also blocks astrocyte activation in respiratory centers during chronic hypoxia and ventilatory acclimatization. However, minocycline cannot reverse ventilatory acclimatization after it is established. Hence, glial cells may provide signals that initiate but do not sustain ventilatory acclimatization.
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Affiliation(s)
- Jennifer A Stokes
- Division of Physiology, Department of Medicine; University of California, San Diego, La Jolla, California
| | - Tara E Arbogast
- Division of Physiology, Department of Medicine; University of California, San Diego, La Jolla, California
| | - Esteban A Moya
- Division of Physiology, Department of Medicine; University of California, San Diego, La Jolla, California
| | - Zhenxing Fu
- Division of Physiology, Department of Medicine; University of California, San Diego, La Jolla, California
| | - Frank L Powell
- Division of Physiology, Department of Medicine; University of California, San Diego, La Jolla, California
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