1
|
Phillips B, Clark J, Martineau É, Rungta RL. Orai, RyR, and IP 3R channels cooperatively regulate calcium signaling in brain mid-capillary pericytes. Commun Biol 2023; 6:493. [PMID: 37149720 PMCID: PMC10164186 DOI: 10.1038/s42003-023-04858-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 04/21/2023] [Indexed: 05/08/2023] Open
Abstract
Pericytes are multifunctional cells of the vasculature that are vital to brain homeostasis, yet many of their fundamental physiological properties, such as Ca2+ signaling pathways, remain unexplored. We performed pharmacological and ion substitution experiments to investigate the mechanisms underlying pericyte Ca2+ signaling in acute cortical brain slices of PDGFRβ-Cre::GCaMP6f mice. We report that mid-capillary pericyte Ca2+ signalling differs from ensheathing type pericytes in that it is largely independent of L- and T-type voltage-gated calcium channels. Instead, Ca2+ signals in mid-capillary pericytes were inhibited by multiple Orai channel blockers, which also inhibited Ca2+ entry triggered by endoplasmic reticulum (ER) store depletion. An investigation into store release pathways indicated that Ca2+ transients in mid-capillary pericytes occur through a combination of IP3R and RyR activation, and that Orai store-operated calcium entry (SOCE) is required to sustain and amplify intracellular Ca2+ increases evoked by the GqGPCR agonist endothelin-1. These results suggest that Ca2+ influx via Orai channels reciprocally regulates IP3R and RyR release pathways in the ER, which together generate spontaneous Ca2+ transients and amplify Gq-coupled Ca2+ elevations in mid-capillary pericytes. Thus, SOCE is a major regulator of pericyte Ca2+ and a target for manipulating their function in health and disease.
Collapse
Affiliation(s)
- Braxton Phillips
- Department of Neuroscience, Université de Montréal, Montréal, QC, Canada
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, H3C3J7, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage, Université de Montréal, Montréal, QC, Canada
| | - Jenna Clark
- Department of Neuroscience, Université de Montréal, Montréal, QC, Canada
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, H3C3J7, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage, Université de Montréal, Montréal, QC, Canada
| | - Éric Martineau
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, H3C3J7, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage, Université de Montréal, Montréal, QC, Canada
| | - Ravi L Rungta
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, H3C3J7, Canada.
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage, Université de Montréal, Montréal, QC, Canada.
| |
Collapse
|
2
|
Rungta RL, Zuend M, Aydin AK, Martineau É, Boido D, Weber B, Charpak S. Diversity of neurovascular coupling dynamics along vascular arbors in layer II/III somatosensory cortex. Commun Biol 2021; 4:855. [PMID: 34244604 PMCID: PMC8270975 DOI: 10.1038/s42003-021-02382-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 06/10/2021] [Indexed: 11/08/2022] Open
Abstract
The spatial-temporal sequence of cerebral blood flow (CBF), cerebral blood volume (CBV) and blood velocity changes triggered by neuronal activation is critical for understanding functional brain imaging. This sequence follows a stereotypic pattern of changes across different zones of the vasculature in the olfactory bulb, the first relay of olfaction. However, in the cerebral cortex, where most human brain mapping studies are performed, the timing of activity evoked vascular events remains controversial. Here we utilized a single whisker stimulation model to map out functional hyperemia along vascular arbours from layer II/III to the surface of primary somatosensory cortex, in anesthetized and awake Thy1-GCaMP6 mice. We demonstrate that sensory stimulation triggers an increase in blood velocity within the mid-capillary bed and a dilation of upstream large capillaries, and the penetrating and pial arterioles. We report that under physiological stimulation, response onset times are highly variable across compartments of different vascular arbours. Furthermore, generating transfer functions (TFs) between neuronal Ca2+ and vascular dynamics across different brain states demonstrates that anesthesia decelerates neurovascular coupling (NVC). This spatial-temporal pattern of vascular events demonstrates functional diversity not only between different brain regions but also at the level of different vascular arbours within supragranular layers of the cerebral cortex.
Collapse
Affiliation(s)
- Ravi L Rungta
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France.
- Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, Canada.
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage, Université de Montréal, Montréal, QC, Canada.
- Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC, Canada.
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Ali-Kemal Aydin
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Éric Martineau
- Faculté de Médecine Dentaire, Université de Montréal, Montréal, QC, Canada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage, Université de Montréal, Montréal, QC, Canada
- Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC, Canada
| | - Davide Boido
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France
- NeuroSpin, Bat. 145, Commissariat à l'Energie Atomique ' Saclay Center, Gif-sur-Yvette, France
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Serge Charpak
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université Paris Descartes, Paris, France.
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France.
| |
Collapse
|
3
|
Mitchell DE, Martineau É, Tazerart S, Araya R. Probing Single Synapses via the Photolytic Release of Neurotransmitters. Front Synaptic Neurosci 2019; 11:19. [PMID: 31354469 PMCID: PMC6640007 DOI: 10.3389/fnsyn.2019.00019] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/24/2019] [Indexed: 11/13/2022] Open
Abstract
The development of two-photon microscopy has revolutionized our understanding of how synapses are formed and how they transform synaptic inputs in dendritic spines-tiny protrusions that cover the dendrites of pyramidal neurons that receive most excitatory synaptic information in the brain. These discoveries have led us to better comprehend the neuronal computations that take place at the level of dendritic spines as well as within neuronal circuits with unprecedented resolution. Here, we describe a method that uses a two-photon (2P) microscope and 2P uncaging of caged neurotransmitters for the activation of single and multiple spines in the dendrites of cortical pyramidal neurons. In addition, we propose a cost-effective description of the components necessary for the construction of a one laser source-2P microscope capable of nearly simultaneous 2P uncaging of neurotransmitters and 2P calcium imaging of the activated spines and nearby dendrites. We provide a brief overview on how the use of these techniques have helped researchers in the last 15 years unravel the function of spines in: (a) information processing; (b) storage; and (c) integration of excitatory synaptic inputs.
Collapse
Affiliation(s)
- Diana E Mitchell
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada.,The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Éric Martineau
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada.,The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Sabrina Tazerart
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada.,The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Roberto Araya
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada.,The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| |
Collapse
|
4
|
Martineau É, Di Polo A, Vande Velde C, Robitaille R. Dynamic neuromuscular remodeling precedes motor-unit loss in a mouse model of ALS. eLife 2018; 7:41973. [PMID: 30320556 PMCID: PMC6234026 DOI: 10.7554/elife.41973] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [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: 09/13/2018] [Accepted: 10/14/2018] [Indexed: 12/13/2022] Open
Abstract
Despite being an early event in ALS, it remains unclear whether the denervation of neuromuscular junctions (NMJ) is simply the first manifestation of a globally degenerating motor neuron. Using in vivo imaging of single axons and their NMJs over a three-month period, we identify that single motor-units are dismantled asynchronously in SOD1G37R mice. We reveal that weeks prior to complete axonal degeneration, the dismantling of axonal branches is accompanied by contemporaneous new axonal sprouting resulting in synapse formation onto nearby NMJs. Denervation events tend to propagate from the first lost NMJ, consistent with a contribution of neuromuscular factors extrinsic to motor neurons, with distal branches being more susceptible. These results show that NMJ denervation in ALS is a complex and dynamic process of continuous denervation and new innervation rather than a manifestation of sudden global motor neuron degeneration. Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a fatal neurodegenerative disorder. It occurs when the neurons that control muscles – the motoneurons – disconnect from their target muscles and die. This causes the muscles to weaken and waste away. More and more muscles become affected over time until eventually the muscles that control breathing also become paralyzed. Most patients die within two to five years of diagnosis. Motoneurons consist of a cell body plus a cable-like structure called the axon. The cell body of each motoneuron sits within the spinal cord, and the axon extends out of the spinal cord to the motoneuron’s target muscle. Within the muscle the axon divides into branches, each of which connects with multiple muscle fibers. The breakdown of these connections, known as neuromuscular junctions, is one of the first signs of ALS. Does a motoneuron lose all of its connections with muscle fibers at once, or do the connections break down a few at a time? This distinction is important as it will help to identify the events that lead to muscle paralysis in ALS. To find out, Martineau et al. studied mice that had two genetic mutations: one that causes ALS and another that produces fluorescent molecules in some motoneurons. This allowed the branches of the motoneurons to be tracked over time with a fluorescence microscope. Martineau et al. found that individual neurons lose their connections to muscle fibers gradually. Moreover, motoneurons grow new branches and form new connections even while losing their old ones. This dual process of pruning and budding lasts for several weeks, until eventually the motoneuron dies. Developing drugs to stabilize neuromuscular junctions during the period when motoneurons gradually disconnect from muscles could be a promising avenue to explore to improve the quality of life of ALS patients. One advantage of this treatment strategy is that neuromuscular junctions in muscles are easier to access than motoneurons inside the spinal cord. To identify potential drugs, future studies will need to focus on the proteins and signals that cause the neuromuscular junctions to break down.
Collapse
Affiliation(s)
- Éric Martineau
- Département de neurosciences, Université de Montréal, Québec, Canada.,Groupe de recherche sur le système nerveux central, Université de Montréal, Québec, Canada
| | - Adriana Di Polo
- Département de neurosciences, Université de Montréal, Québec, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal, Québec, Canada
| | - Christine Vande Velde
- Département de neurosciences, Université de Montréal, Québec, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal, Québec, Canada
| | - Richard Robitaille
- Département de neurosciences, Université de Montréal, Québec, Canada.,Groupe de recherche sur le système nerveux central, Université de Montréal, Québec, Canada
| |
Collapse
|
5
|
Abstract
AbstractUp to 90% of people with severe traumatic brain injury (TBI) report dissatisfaction with the status of their leisure participation and/or social integration. Yet, there are virtually no studies that have investigated the benefits of interventions that target leisure specifically for this population. The purpose of this study was to determine whether the Leisure Education Program (Carbonneau, Fontaine, & Lussier, 2006) designed to assist people with stroke to engage in meaningful leisure activities, build leisure self-efficacy and promote general wellbeing would have similar benefits for survivors of TBI. We recruited three community-dwelling survivors of TBI to participate in a 10-week leisure program. All three participants reported some benefit in leisure satisfaction and self-efficacy. This extended to improvements in general wellbeing and health-related quality of life for two of the three. These findings suggest that further investigations into the benefits of leisure education for adults with TBI should be conducted.
Collapse
|