1
|
Martineau É, Malescot A, Elmkinssi N, Rungta RL. Distal activity patterns shape the spatial specificity of neurovascular coupling. Nat Neurosci 2024:10.1038/s41593-024-01756-7. [PMID: 39232066 DOI: 10.1038/s41593-024-01756-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/07/2024] [Indexed: 09/06/2024]
Abstract
Neurovascular coupling links brain activity to local changes in blood flow, forming the basis for non-invasive brain mapping. Using multiscale imaging, we investigated how vascular activity spatially relates to neuronal activity elicited by single whiskers across different columns and layers of mouse cortex. Here we show that mesoscopic hemodynamic signals quantitatively reflect neuronal activity across space but are composed of a highly heterogeneous pattern of responses across individual vessel segments that is poorly predicted by local neuronal activity. Rather, this heterogeneity is dependent on vessel directionality, specifically in thalamocortical input layer 4, where capillaries respond preferentially to neuronal activity patterns along their downstream perfusion domain. Thus, capillaries fine-tune blood flow based on distant activity and encode laminar-specific activity patterns. These findings imply that vascular anatomy sets a resolution limit on functional imaging signals, where individual blood vessels inaccurately report neuronal activity in their immediate vicinity but, instead, integrate activity patterns along the vascular arbor.
Collapse
Affiliation(s)
- Éric Martineau
- Centre for Interdisciplinary Research on Brain and Learning (CIRCA), Université de Montréal, Montréal, Quebec, Canada
- Department of Physiology and Pharmacology, Université de Montréal, Montréal, Quebec, Canada
| | - Antoine Malescot
- Centre for Interdisciplinary Research on Brain and Learning (CIRCA), Université de Montréal, Montréal, Quebec, Canada
- Department of Physiology and Pharmacology, Université de Montréal, Montréal, Quebec, Canada
| | - Nouha Elmkinssi
- Centre for Interdisciplinary Research on Brain and Learning (CIRCA), Université de Montréal, Montréal, Quebec, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada
| | - Ravi L Rungta
- Centre for Interdisciplinary Research on Brain and Learning (CIRCA), Université de Montréal, Montréal, Quebec, Canada.
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada.
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, Quebec, Canada.
| |
Collapse
|
2
|
Wellman S, Forrest AM, Douglas MM, Subbaraman A, Zhang G, Kozai TDY. Dynamic changes in structure and function of brain mural cells around chronically implanted microelectrodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.11.598494. [PMID: 38915601 PMCID: PMC11195141 DOI: 10.1101/2024.06.11.598494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Integration of neural interfaces with minimal tissue disruption in the brain is ideal to develop robust tools that can address essential neuroscience questions and combat neurological disorders. However, implantation of intracortical devices provokes severe tissue inflammation within the brain, which requires a high metabolic demand to support a complex series of cellular events mediating tissue degeneration and wound healing. Pericytes, peri-vascular cells involved in blood-brain barrier maintenance, vascular permeability, waste clearance, and angiogenesis, have recently been implicated as potential perpetuators of neurodegeneration in brain injury and disease. While the intimate relationship between pericytes and the cortical microvasculature have been explored in other disease states, their behavior following microelectrode implantation, which is responsible for direct blood vessel disruption and dysfunction, is currently unknown. Using two-photon microscopy we observed dynamic changes in the structure and function of pericytes during implantation of a microelectrode array over a 4-week implantation period. Pericytes respond to electrode insertion through transient increases in intracellular calcium and underlying constriction of capillary vessels. Within days following the initial insertion, we observed an influx of new, proliferating pericytes which contribute to new blood vessel formation. Additionally, we discovered a potentially novel population of reactive immune cells in close proximity to the electrode-tissue interface actively engaging in encapsulation of the microelectrode array. Finally, we determined that intracellular pericyte calcium can be modulated by intracortical microstimulation in an amplitude- and frequency-dependent manner. This study provides a new perspective on the complex biological sequelae occurring the electrode-tissue interface and will foster new avenues of potential research consideration and lead to development of more advanced therapeutic interventions towards improving the biocompatibility of neural electrode technology.
Collapse
|
3
|
Shrouder JJ, Calandra GM, Filser S, Varga DP, Besson-Girard S, Mamrak U, Dorok M, Bulut-Impraim B, Seker FB, Gesierich B, Laredo F, Wehn AC, Khalin I, Bayer P, Liesz A, Gokce O, Plesnila N. Continued dysfunction of capillary pericytes promotes no-reflow after experimental stroke in vivo. Brain 2024; 147:1057-1074. [PMID: 38153327 DOI: 10.1093/brain/awad401] [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: 03/17/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 12/29/2023] Open
Abstract
Incomplete reperfusion of the microvasculature ('no-reflow') after ischaemic stroke damages salvageable brain tissue. Previous ex vivo studies suggest pericytes are vulnerable to ischaemia and may exacerbate no-reflow, but the viability of pericytes and their association with no-reflow remains under-explored in vivo. Using longitudinal in vivo two-photon single-cell imaging over 7 days, we showed that 87% of pericytes constrict during cerebral ischaemia and remain constricted post reperfusion, and 50% of the pericyte population are acutely damaged. Moreover, we revealed ischaemic pericytes to be fundamentally implicated in capillary no-reflow by limiting and arresting blood flow within the first 24 h post stroke. Despite sustaining acute membrane damage, we observed that over half of all cortical pericytes survived ischaemia and responded to vasoactive stimuli, upregulated unique transcriptomic profiles and replicated. Finally, we demonstrated the delayed recovery of capillary diameter by ischaemic pericytes after reperfusion predicted vessel reconstriction in the subacute phase of stroke. Cumulatively, these findings demonstrate that surviving cortical pericytes remain both viable and promising therapeutic targets to counteract no-reflow after ischaemic stroke.
Collapse
Affiliation(s)
- Joshua James Shrouder
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Gian Marco Calandra
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
| | - Severin Filser
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- Core Research Facilities and Services-Light Microscope Facility, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Daniel Peter Varga
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Simon Besson-Girard
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Uta Mamrak
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
| | - Maximilian Dorok
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
| | - Buket Bulut-Impraim
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Fatma Burcu Seker
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Benno Gesierich
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Fabio Laredo
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
| | - Antonia Clarissa Wehn
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- Department of Neurosurgery, LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
| | - Igor Khalin
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- Normandie University, UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Institute Blood and Brain @ Caen-Normandie (BB@C), 14000 Caen, France
| | - Patrick Bayer
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
| | - Arthur Liesz
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Ozgun Gokce
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research (ISD), LMU University Hospital, Ludwig-Maximilians-University (LMU) Munich, 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| |
Collapse
|
4
|
Picoli CDC, Birbrair A, Li Z. Pericytes as the Orchestrators of Vasculature and Adipogenesis. Genes (Basel) 2024; 15:126. [PMID: 38275607 PMCID: PMC10815550 DOI: 10.3390/genes15010126] [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: 12/19/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
Pericytes (PCs) are located surrounding the walls of small blood vessels, particularly capillaries and microvessels. In addition to their functions in maintaining vascular integrity, participating in angiogenesis, and regulating blood flow, PCs also serve as a reservoir for multi-potent stem/progenitor cells in white, brown, beige, and bone marrow adipose tissues. Due to the complex nature of this cell population, the identification and characterization of PCs has been challenging. A comprehensive understanding of the heterogeneity of PCs may enhance their potential as therapeutic targets for metabolic syndromes or bone-related diseases. This mini-review summarizes multiple PC markers commonly employed in lineage-tracing studies, with an emphasis on their contribution to adipogenesis and functions in different adipose depots under diverse metabolic conditions.
Collapse
Affiliation(s)
| | - Alexander Birbrair
- Department of Dermatology, University of Wisconsin-Madison, Medical Sciences Center, Madison, WI 53706, USA;
| | - Ziru Li
- Center for Molecular Medicine, MaineHealth Institute for Research, Scarborough, ME 04074, USA;
| |
Collapse
|
5
|
Zhang Y, Jiang M, Gao Y, Zhao W, Wu C, Li C, Li M, Wu D, Wang W, Ji X. "No-reflow" phenomenon in acute ischemic stroke. J Cereb Blood Flow Metab 2024; 44:19-37. [PMID: 37855115 PMCID: PMC10905637 DOI: 10.1177/0271678x231208476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 08/04/2023] [Accepted: 09/13/2023] [Indexed: 10/20/2023]
Abstract
Acute ischemic stroke (AIS) afflicts millions of individuals worldwide. Despite the advancements in thrombolysis and thrombectomy facilitating proximal large artery recanalization, the resultant distal hypoperfusion, referred to "no-reflow" phenomenon, often impedes the neurological function restoration in patients. Over half a century of scientific inquiry has validated the existence of cerebral "no-reflow" in both animal models and human subjects. Furthermore, the correlation between "no-reflow" and adverse clinical outcomes underscores the necessity to address this phenomenon as a pivotal strategy for enhancing AIS prognoses. The underlying mechanisms of "no-reflow" are multifaceted, encompassing the formation of microemboli, microvascular compression and contraction. Moreover, a myriad of complex mechanisms warrant further investigation. Insights gleaned from mechanistic exploration have prompted advancements in "no-reflow" treatment, including microthrombosis therapy, which has demonstrated clinical efficacy in improving patient prognoses. The stagnation in current "no-reflow" diagnostic methods imposes limitations on the timely application of combined therapy on "no-reflow" post-recanalization. This narrative review will traverse the historical journey of the "no-reflow" phenomenon, delve into its underpinnings in AIS, and elucidate potential therapeutic and diagnostic strategies. Our aim is to equip readers with a swift comprehension of the "no-reflow" phenomenon and highlight critical points for future research endeavors.
Collapse
Affiliation(s)
- Yang Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Miaowen Jiang
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yuan Gao
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Wenbo Zhao
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Chuanjie Wu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Chuanhui Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Ming Li
- China-America Institute of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Di Wu
- China-America Institute of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Wu Wang
- Institute of Diagnostic and Interventional Radiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xunming Ji
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- China-America Institute of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
6
|
Gaikwad S, Senapati S, Haque MA, Kayed R. Senescence, brain inflammation, and oligomeric tau drive cognitive decline in Alzheimer's disease: Evidence from clinical and preclinical studies. Alzheimers Dement 2024; 20:709-727. [PMID: 37814508 PMCID: PMC10841264 DOI: 10.1002/alz.13490] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 10/11/2023]
Abstract
Aging, tau pathology, and chronic inflammation in the brain play crucial roles in synaptic loss, neurodegeneration, and cognitive decline in tauopathies, including Alzheimer's disease. Senescent cells accumulate in the aging brain, accelerate the aging process, and promote tauopathy progression through their abnormal inflammatory secretome known as the senescence-associated secretory phenotype (SASP). Tau oligomers (TauO)-the most neurotoxic tau species-are known to induce senescence and the SASP, which subsequently promote neuropathology, inflammation, oxidative stress, synaptic dysfunction, neuronal death, and cognitive dysfunction. TauO, brain inflammation, and senescence are associated with heterogeneity in tauopathy progression and cognitive decline. However, the underlying mechanisms driving the disease heterogeneity remain largely unknown, impeding the development of therapies for tauopathies. Based on clinical and preclinical evidence, this review highlights the critical role of TauO and senescence in neurodegeneration. We discuss key knowledge gaps and potential strategies for targeting senescence and TauO to treat tauopathies. HIGHLIGHTS: Senescence, oligomeric Tau (TauO), and brain inflammation accelerate the aging process and promote the progression of tauopathies, including Alzheimer's disease. We discuss their role in contributing to heterogeneity in tauopathy and cognitive decline. We highlight strategies to target senescence and TauO to treat tauopathies while addressing key knowledge gaps.
Collapse
Affiliation(s)
- Sagar Gaikwad
- The Mitchell Center for Neurodegenerative Diseasesand Department of NeurologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Sudipta Senapati
- The Mitchell Center for Neurodegenerative Diseasesand Department of NeurologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Md. Anzarul Haque
- The Mitchell Center for Neurodegenerative Diseasesand Department of NeurologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Rakez Kayed
- The Mitchell Center for Neurodegenerative Diseasesand Department of NeurologyUniversity of Texas Medical BranchGalvestonTexasUSA
| |
Collapse
|
7
|
Iba C, Abe Y, Tanaka KF. Optogenetic demonstration of the involvement of SMA-negative mural cells in the regulation of cerebral blood flow. Front Physiol 2023; 14:1322250. [PMID: 38187133 PMCID: PMC10771846 DOI: 10.3389/fphys.2023.1322250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/08/2023] [Indexed: 01/09/2024] Open
Abstract
Mural cells are critical components of the cerebral vasculature. They are categorized into three primary subsets: arteriole smooth muscle cells (aSMCs), pericytes (PCs) and venule smooth muscle cells (vSMCs). It is well known that aSMCs can directly regulate cerebral blood flow (CBF) with their own contraction and dilation mechanisms. On the other hand, the direct involvement of PCs or vSMCs in CBF regulation is controversial. This ambiguity is largely due to the lack of specifically manipulable tools to isolate their function. To address this issue, we employed a set-subtraction approach by using a combination of tTA-mediated gene induction and Cre-mediated gene excision. We developed transgenic mice expressing optical actuators, channelrhodopsin-2 (ChR2) and photoactivated adenylyl cyclase (PAC) in smooth muscle actin (SMA)-negative mural cells that lack the machinery for SMA-mediated vasoregulation. Using these mouse models, we assessed CBF alterations in response to optical stimulation using laser Doppler techniques. Our results showed that optical stimulation induced notable CBF changes in both models. This study provides evidence for the potential regulatory role of PCs and vSMCs in cerebral hemodynamics and introduces powerful tools to specifically manipulate these cell types in vascular neurobiology.
Collapse
Affiliation(s)
| | | | - Kenji F. Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan
| |
Collapse
|
8
|
Alarcon-Martinez L, Shiga Y, Villafranca-Baughman D, Cueva Vargas JL, Vidal Paredes IA, Quintero H, Fortune B, Danesh-Meyer H, Di Polo A. Neurovascular dysfunction in glaucoma. Prog Retin Eye Res 2023; 97:101217. [PMID: 37778617 DOI: 10.1016/j.preteyeres.2023.101217] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Retinal ganglion cells, the neurons that die in glaucoma, are endowed with a high metabolism requiring optimal provision of oxygen and nutrients to sustain their activity. The timely regulation of blood flow is, therefore, essential to supply firing neurons in active areas with the oxygen and glucose they need for energy. Many glaucoma patients suffer from vascular deficits including reduced blood flow, impaired autoregulation, neurovascular coupling dysfunction, and blood-retina/brain-barrier breakdown. These processes are tightly regulated by a community of cells known as the neurovascular unit comprising neurons, endothelial cells, pericytes, Müller cells, astrocytes, and microglia. In this review, the neurovascular unit takes center stage as we examine the ability of its members to regulate neurovascular interactions and how their function might be altered during glaucomatous stress. Pericytes receive special attention based on recent data demonstrating their key role in the regulation of neurovascular coupling in physiological and pathological conditions. Of particular interest is the discovery and characterization of tunneling nanotubes, thin actin-based conduits that connect distal pericytes, which play essential roles in the complex spatial and temporal distribution of blood within the retinal capillary network. We discuss cellular and molecular mechanisms of neurovascular interactions and their pathophysiological implications, while highlighting opportunities to develop strategies for vascular protection and regeneration to improve functional outcomes in glaucoma.
Collapse
Affiliation(s)
- Luis Alarcon-Martinez
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - Yukihiro Shiga
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Deborah Villafranca-Baughman
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Jorge L Cueva Vargas
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Isaac A Vidal Paredes
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Heberto Quintero
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Healthy, Portland, OR, USA
| | - Helen Danesh-Meyer
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada.
| |
Collapse
|
9
|
Fu J, Liang H, Yuan P, Wei Z, Zhong P. Brain pericyte biology: from physiopathological mechanisms to potential therapeutic applications in ischemic stroke. Front Cell Neurosci 2023; 17:1267785. [PMID: 37780206 PMCID: PMC10536258 DOI: 10.3389/fncel.2023.1267785] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023] Open
Abstract
Pericytes play an indispensable role in various organs and biological processes, such as promoting angiogenesis, regulating microvascular blood flow, and participating in immune responses. Therefore, in this review, we will first introduce the discovery and development of pericytes, identification methods and functional characteristics, then focus on brain pericytes, on the one hand, to summarize the functions of brain pericytes under physiological conditions, mainly discussing from the aspects of stem cell characteristics, contractile characteristics and paracrine characteristics; on the other hand, to summarize the role of brain pericytes under pathological conditions, mainly taking ischemic stroke as an example. Finally, we will discuss and analyze the application and development of pericytes as therapeutic targets, providing the research basis and direction for future microvascular diseases, especially ischemic stroke treatment.
Collapse
Affiliation(s)
- Jiaqi Fu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
- Department of Neurology, Shidong Hospital, Yangpu District, Shanghai, China
| | - Huazheng Liang
- Monash Suzhou Research Institute, Suzhou, Jiangsu, China
| | - Ping Yuan
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Zhenyu Wei
- Department of Neurology, Shidong Hospital, Yangpu District, Shanghai, China
| | - Ping Zhong
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
- Department of Neurology, Shidong Hospital, Yangpu District, Shanghai, China
| |
Collapse
|
10
|
Murata J, Unekawa M, Kudo Y, Kotani M, Kanno I, Izawa Y, Tomita Y, Tanaka KF, Nakahara J, Masamoto K. Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing. Stroke 2023; 54:2135-2144. [PMID: 37309687 DOI: 10.1161/strokeaha.122.042416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/05/2023] [Indexed: 06/14/2023]
Abstract
BACKGROUND Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. METHODS To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. RESULTS Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. CONCLUSIONS Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.
Collapse
Affiliation(s)
- Juri Murata
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Miyuki Unekawa
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Yuya Kudo
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Maho Kotani
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
| | - Iwao Kanno
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, Japan (I.K.)
| | - Yoshikane Izawa
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Yutaka Tomita
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
- Tomita Hospital, Aichi, Japan (Y.T.)
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research (K.F.T.), Keio University School of Medicine, Tokyo, Japan
| | - Jin Nakahara
- Department of Neurology (M.U., Y.I., Y.T., J.N.), Keio University School of Medicine, Tokyo, Japan
| | - Kazuto Masamoto
- Graduate School of Informatics and Engineering (J.M., Y.K., M.K., K.M.), University of Electro-Communications, Tokyo, Japan
- Center for Neuroscience and Biomedical Engineering (K.M.), University of Electro-Communications, Tokyo, Japan
| |
Collapse
|
11
|
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] [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
|
12
|
Sargent SM, Bonney SK, Li Y, Stamenkovic S, Takeno M, Coelho-Santos V, Shih AY. Endothelial structure contributes to heterogeneity in brain capillary diameter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.26.538503. [PMID: 37163126 PMCID: PMC10168366 DOI: 10.1101/2023.04.26.538503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The high metabolic demand of brain tissue is supported by a constant supply of blood through dense microvascular networks. Capillaries are the smallest class of vessels and vary in diameter between ∼2 to 5 μm in the brain. This diameter range plays a significant role in the optimization of blood flow resistance, blood cell distribution, and oxygen extraction. The control of capillary diameter has largely been ascribed to pericyte contractility, but it remains unclear if endothelial wall architecture also contributes to capillary diameter heterogeneity. Here, we use public, large-scale volume electron microscopy data from mouse cortex (MICrONS Explorer, Cortical MM^3) to examine how endothelial cell number, endothelial cell thickness, and pericyte coverage relates to microvascular lumen size. We find that transitional vessels near the penetrating arteriole and ascending venule are composed of 2 to 5 interlocked endothelial cells, while the numerous capillary segments intervening these zones are composed of either 1 or 2 endothelial cells, with roughly equal proportions. The luminal area and diameter is on average slightly larger with capillary segments composed of 2 interlocked endothelial cells versus 1 endothelial cell. However, this difference is insufficient to explain the full range of capillary diameters seen in vivo. This suggests that both endothelial structure and other influences, such as pericyte tone, contribute to the basal diameter and optimized perfusion of brain capillaries.
Collapse
|
13
|
Eisenmenger LB, Peret A, Famakin BM, Spahic A, Roberts GS, Bockholt JH, Johnson KM, Paulsen JS. Vascular contributions to Alzheimer's disease. Transl Res 2023; 254:41-53. [PMID: 36529160 PMCID: PMC10481451 DOI: 10.1016/j.trsl.2022.12.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and is characterized by progressive neurodegeneration and cognitive decline. Understanding the pathophysiology underlying AD is paramount for the management of individuals at risk of and suffering from AD. The vascular hypothesis stipulates a relationship between cardiovascular disease and AD-related changes although the nature of this relationship remains unknown. In this review, we discuss several potential pathological pathways of vascular involvement in AD that have been described including dysregulation of neurovascular coupling, disruption of the blood brain barrier, and reduced clearance of metabolite waste such as beta-amyloid, a toxic peptide considered the hallmark of AD. We will also discuss the two-hit hypothesis which proposes a 2-step positive feedback loop in which microvascular insults precede the accumulation of Aß and are thought to be at the origin of the disease development. At neuroimaging, signs of vascular dysfunction such as chronic cerebral hypoperfusion have been demonstrated, appearing early in AD, even before cognitive decline and alteration of traditional biomarkers. Cerebral small vessel disease such as cerebral amyloid angiopathy, characterized by the aggregation of Aß in the vessel wall, is highly prevalent in vascular dementia and AD patients. Current data is unclear whether cardiovascular disease causes, precipitates, amplifies, precedes, or simply coincides with AD. Targeted imaging tools to quantitatively evaluate the intracranial vasculature and longitudinal studies in individuals at risk for or in the early stages of the AD continuum could be critical in disentangling this complex relationship between vascular disease and AD.
Collapse
Affiliation(s)
- Laura B Eisenmenger
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Anthony Peret
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Bolanle M Famakin
- Department of Neurology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alma Spahic
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Grant S Roberts
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Jeremy H Bockholt
- Tri-Institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS), Georgia State University, Georgia Institute of Technology, and Emory University, Atlanta, Georgia
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Jane S Paulsen
- Department of Neurology, University of Wisconsin-Madison, Madison, Wisconsin.
| |
Collapse
|
14
|
The role of the blood-brain barrier during neurological disease and infection. Biochem Soc Trans 2023; 51:613-626. [PMID: 36929707 DOI: 10.1042/bst20220830] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/18/2023]
Abstract
A healthy brain is protected by the blood-brain barrier (BBB), which is formed by the endothelial cells that line brain capillaries. The BBB plays an extremely important role in supporting normal neuronal function by maintaining the homeostasis of the brain microenvironment and restricting pathogen and toxin entry to the brain. Dysfunction of this highly complex and regulated structure can be life threatening. BBB dysfunction is implicated in many neurological diseases such as stroke, Alzheimer's disease, multiple sclerosis, and brain infections. Among other mechanisms, inflammation and/or flow disturbances are major causes of BBB dysfunction in neurological infections and diseases. In particular, in ischaemic stroke, both inflammation and flow disturbances contribute to BBB disruption, leading to devastating consequences. While a transient or minor disruption to the barrier function could be tolerated, chronic or a total breach of the barrier can result in irreversible brain damage. It is worth noting that timing and extent of BBB disruption play an important role in the process of any repair of brain damage and treatment strategies. This review evaluates and summarises some of the latest research on the role of the BBB during neurological disease and infection with a focus on the effects of inflammation and flow disturbances on the BBB. The BBB's crucial role in protecting the brain is also the bottleneck in central nervous system drug development. Therefore, innovative strategies to carry therapeutics across the BBB and novel models to screen drugs, and to study the complex, overlapping mechanisms of BBB disruption are urgently needed.
Collapse
|
15
|
Klug NR, Sancho M, Gonzales AL, Heppner TJ, O’Brien RIC, Hill-Eubanks D, Nelson MT. Intraluminal pressure elevates intracellular calcium and contracts CNS pericytes: Role of voltage-dependent calcium channels. Proc Natl Acad Sci U S A 2023; 120:e2216421120. [PMID: 36802432 PMCID: PMC9992766 DOI: 10.1073/pnas.2216421120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/24/2023] [Indexed: 02/23/2023] Open
Abstract
Arteriolar smooth muscle cells (SMCs) and capillary pericytes dynamically regulate blood flow in the central nervous system in the face of fluctuating perfusion pressures. Pressure-induced depolarization and Ca2+ elevation provide a mechanism for regulation of SMC contraction, but whether pericytes participate in pressure-induced changes in blood flow remains unknown. Here, utilizing a pressurized whole-retina preparation, we found that increases in intraluminal pressure in the physiological range induce contraction of both dynamically contractile pericytes in the arteriole-proximate transition zone and distal pericytes of the capillary bed. We found that the contractile response to pressure elevation was slower in distal pericytes than in transition zone pericytes and arteriolar SMCs. Pressure-evoked elevation of cytosolic Ca2+ and contractile responses in SMCs were dependent on voltage-dependent Ca2+ channel (VDCC) activity. In contrast, Ca2+ elevation and contractile responses were partially dependent on VDCC activity in transition zone pericytes and independent of VDCC activity in distal pericytes. In both transition zone and distal pericytes, membrane potential at low inlet pressure (20 mmHg) was approximately -40 mV and was depolarized to approximately -30 mV by an increase in pressure to 80 mmHg. The magnitude of whole-cell VDCC currents in freshly isolated pericytes was approximately half that measured in isolated SMCs. Collectively, these results indicate a loss of VDCC involvement in pressure-induced constriction along the arteriole-capillary continuum. They further suggest that alternative mechanisms and kinetics of Ca2+ elevation, contractility, and blood flow regulation exist in central nervous system capillary networks, distinguishing them from neighboring arterioles.
Collapse
Affiliation(s)
- Nicholas R. Klug
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT05405
| | - Maria Sancho
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT05405
| | - Albert L. Gonzales
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT05405
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV89557
| | - Thomas J. Heppner
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT05405
| | | | - David Hill-Eubanks
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT05405
| | - Mark T. Nelson
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT05405
- Division of Cardiovascular Sciences, University of Manchester, ManchesterM13 9PL, UK
| |
Collapse
|
16
|
Cheng J, Jiang J, He B, Lin WJ, Li Y, Duan J, Li H, Huang X, Cai J, Xie J, Zhang Z, Yang Y, Xu Y, Hu X, Wu M, Zhuo X, Liu Q, Shi Z, Yu P, Rong X, Ye X, Saw PE, Wu LJ, Simone CB, Chua MLK, Mai HQ, Tang Y. A phase 2 study of thalidomide for the treatment of radiation-induced blood-brain barrier injury. Sci Transl Med 2023; 15:eabm6543. [PMID: 36812346 DOI: 10.1126/scitranslmed.abm6543] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Radiation-induced brain injury (RIBI) is a debilitating sequela after radiotherapy to treat head and neck cancer, and 20 to 30% of patients with RIBI fail to respond to or have contraindications to the first-line treatments of bevacizumab and corticosteroids. Here, we reported a Simon's minmax two-stage, single-arm, phase 2 clinical trial (NCT03208413) to assess the efficacy of thalidomide in patients with RIBI who were unresponsive to or had contraindications to bevacizumab and corticosteroid therapies. The trial met its primary endpoint, with 27 of 58 patients enrolled showing ≥25% reduction in the volume of cerebral edema on fluid-attenuated inversion recovery-magnetic resonance imaging (FLAIR-MRI) after treatment (overall response rate, 46.6%; 95% CI, 33.3 to 60.1%). Twenty-five (43.1%) patients demonstrated a clinical improvement based on the Late Effects Normal Tissues-Subjective, Objective, Management, Analytic (LENT/SOMA) scale, and 36 (62.1%) experienced cognitive improvement based on the Montreal Cognitive Assessment (MoCA) scores. In a mouse model of RIBI, thalidomide restored the blood-brain barrier and cerebral perfusion, which were attributed to the functional rescue of pericytes secondary to elevation of platelet-derived growth factor receptor β (PDGFRβ) expression by thalidomide. Our data thus demonstrate the therapeutic potential of thalidomide for the treatment of radiation-induced cerebral vasculature impairment.
Collapse
Affiliation(s)
- Jinping Cheng
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Jingru Jiang
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Baixuan He
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Wei-Jye Lin
- Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan 528200, China
| | - Yi Li
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Jingjing Duan
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Honghong Li
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Xiaolong Huang
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Jinhua Cai
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Jiatian Xie
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Zhan Zhang
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Yuhua Yang
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Yongteng Xu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Xia Hu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Minyi Wu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Xiaohuang Zhuo
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Qiang Liu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Zhongshan Shi
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Pei Yu
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Xiaoming Rong
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Xiaojing Ye
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Sun Yat-sen University, Guangzhou 510080, China
| | - Phei Er Saw
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA.,Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
| | - Charles B Simone
- Department of Radiation Oncology, New York Proton Center, New York, NY 10035, USA
| | - Melvin L K Chua
- Department of Head and Neck and Thoracic Cancers, Division of Radiation Oncology, National Cancer Centre Singapore, Singapore 169610, Singapore.,Division of Medical Sciences, National Cancer Centre Singapore, Singapore 169610, Singapore.,Oncology Academic Programme, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Hai-Qiang Mai
- Department of Nasopharyngeal Carcinoma, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou 510060, China
| | - Yamei Tang
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Brain Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-sen Memorial Hospital, Foshan 528200, China
| |
Collapse
|
17
|
Oishi M, Passlick S, Yamazaki Y, Unekawa M, Adachi R, Yamada M, Imayoshi I, Abe Y, Steinhäuser C, Tanaka KF. Separate optogenetic manipulation of Nerve/glial antigen 2 (NG2) glia and mural cells using the NG2 promoter. Glia 2023; 71:317-333. [PMID: 36165697 DOI: 10.1002/glia.24273] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 11/09/2022]
Abstract
Nerve/glial antigen 2 (NG2) is a protein marker of NG2 glia and mural cells, and NG2 promoter activity is utilized to target these cells. However, the NG2 promoter cannot target NG2 glia and mural cells separately. This has been an obstacle for NG2 glia-specific manipulation. Here, we developed transgenic mice in which either cell type can be targeted using the NG2 promoter. We selected a tetracycline-controllable gene induction system for cell type-specific transgene expression, and generated NG2-tetracycline transactivator (tTA) transgenic lines. We crossed tTA lines with the tetO-ChR2 (channelrhodopsin-2)-EYFP line to characterize tTA-dependent transgene induction. We isolated two unique NG2-tTA mouse lines: one that induced ChR2-EYFP only in mural cells, likely due to the chromosomal position effect of NG2-tTA insertion, and the other that induced it in both cell types. We then applied a Cre-mediated set-subtraction strategy to the latter case and eliminated ChR2-EYFP from mural cells, resulting in NG2 glia-specific transgene induction. We further demonstrated that tTA-dependent ChR2 expression could manipulate cell function. Optogenetic mural cell activation decreased cerebral blood flow, as previously reported, indicating that tTA-mediated ChR2 expression was sufficient to impact cellular function. ChR2-mediated depolarization was observed in NG2 glia in acute hippocampal slices. In addition, ChR2-mediated depolarization of NG2 glia inhibited their proliferation but promoted their differentiation in juvenile mice. Since the tTA-tetO combination is expandable, the mural cell-specific NG2-tTA line and the NG2 glia-specific NG2-tTA line will permit us to conduct observational and manipulation studies to examine in vivo function of these cells separately.
Collapse
Affiliation(s)
- Mitsuhiro Oishi
- Division of Brain Sciences, Keio University School of Medicine, Tokyo, Japan
| | - Stefan Passlick
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan
| | - Miyuki Unekawa
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Ruka Adachi
- Division of Brain Sciences, Keio University School of Medicine, Tokyo, Japan
| | - Mayumi Yamada
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Itaru Imayoshi
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.,Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yoshifumi Abe
- Division of Brain Sciences, Keio University School of Medicine, Tokyo, Japan
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Kenji F Tanaka
- Division of Brain Sciences, Keio University School of Medicine, Tokyo, Japan
| |
Collapse
|
18
|
Sargent SM, Bonney SK, Li Y, Stamenkovic S, Takeno MM, Coelho-Santos V, Shih AY. Endothelial structure contributes to heterogeneity in brain capillary diameter. VASCULAR BIOLOGY (BRISTOL, ENGLAND) 2023; 5:e230010. [PMID: 37582180 PMCID: PMC10503221 DOI: 10.1530/vb-23-0010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 08/15/2023] [Indexed: 08/17/2023]
Abstract
The high metabolic demand of brain tissue is supported by a constant supply of blood flow through dense microvascular networks. Capillaries are the smallest class of vessels in the brain and their lumens vary in diameter between ~2 and 5 μm. This diameter range plays a significant role in optimizing blood flow resistance, blood cell distribution, and oxygen extraction. The control of capillary diameter has largely been ascribed to pericyte contractility, but it remains unclear if the architecture of the endothelial wall also contributes to capillary diameter. Here, we use public, large-scale volume electron microscopy data from mouse cortex (MICrONS Explorer, Cortical mm3) to examine how endothelial cell number, endothelial cell thickness, and pericyte coverage relates to microvascular lumen size. We find that transitional vessels near the penetrating arteriole and ascending venule are composed of two to six interlocked endothelial cells, while the capillaries intervening these zones are composed of either one or two endothelial cells, with roughly equal proportions. The luminal area and diameter are on average slightly larger with capillary segments composed of two interlocked endothelial cells vs one endothelial cell. However, this difference is insufficient to explain the full range of capillary diameters seen in vivo. This suggests that both endothelial structure and other influences, including pericyte tone, contribute to the basal diameter and optimized perfusion of brain capillaries.
Collapse
Affiliation(s)
- Sheridan M Sargent
- Neuroscience Graduate Program, University of Washington, Seattle, Washington, USA
| | - Stephanie K Bonney
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, USA
| | - Yuandong Li
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, USA
| | - Stefan Stamenkovic
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, USA
| | - Marc M Takeno
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Vanessa Coelho-Santos
- Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Portugal
- Institute of Nuclear Sciences Applied to Health, University of Coimbra, Portugal
| | - Andy Y Shih
- Neuroscience Graduate Program, University of Washington, Seattle, Washington, USA
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| |
Collapse
|
19
|
Niizawa T, Sakuraba R, Kusaka T, Kurihara Y, Sugashi T, Kawaguchi H, Kanno I, Masamoto K. Spatiotemporal analysis of blood plasma and blood cell flow fluctuations of cerebral microcirculation in anesthetized rats. J Cereb Blood Flow Metab 2023; 43:138-152. [PMID: 36138557 PMCID: PMC9875347 DOI: 10.1177/0271678x221125743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 08/09/2022] [Accepted: 08/13/2022] [Indexed: 01/28/2023]
Abstract
Cerebral hemodynamics fluctuates spontaneously over broad frequency ranges. However, its spatiotemporal coherence of flow oscillations in cerebral microcirculation remains incompletely understood. The objective of this study was to characterize the spatiotemporal fluctuations of red blood cells (RBCs) and plasma flow in the rat cerebral microcirculation by simultaneously imaging their dynamic behaviors. Comparisons of changes in cross-section diameters between RBC and plasma flow showed dissociations in penetrating arterioles. The results indicate that vasomotion has the least effect on the lateral movement of circulating RBCs, resulting in variable changes in plasma layer thickness. Parenchymal capillaries exhibited slow fluctuations in RBC velocity (0.1 to 0.3 Hz), regardless of capillary diameter fluctuations (<0.1 Hz). Temporal fluctuations and the velocity of RBCs decreased significantly at divergent capillary bifurcations. The results indicate that a transit of RBCs generates flow resistance in the capillaries and that slow velocity fluctuations of the RBCs are subject to a number of bifurcations. In conclusion, the high-frequency oscillation of the blood flow is filtered at the bifurcation through the capillary networks. Therefore, a number of bifurcations in the cerebral microcirculation may contribute to the power of low-frequency oscillations.
Collapse
Affiliation(s)
- Tomoya Niizawa
- Faculty of Informatics and Engineering, University of
Electro-Communications, Tokyo, Japan
| | - Ruka Sakuraba
- Faculty of Informatics and Engineering, University of
Electro-Communications, Tokyo, Japan
| | - Tomoya Kusaka
- Faculty of Informatics and Engineering, University of
Electro-Communications, Tokyo, Japan
| | - Yuika Kurihara
- Faculty of Informatics and Engineering, University of
Electro-Communications, Tokyo, Japan
| | - Takuma Sugashi
- Faculty of Informatics and Engineering, University of
Electro-Communications, Tokyo, Japan
- Center for Neuroscience and Biomedical Engineering,
University of Electro-Communications, Tokyo, Japan
| | - Hiroshi Kawaguchi
- Human Informatics and Interaction Research Institute,
National Institute of Advanced Industrial Science and Technology
(AIST), Ibaraki, Japan
| | - Iwao Kanno
- Department of Functional Brain Imaging Research,
National Institute of Radiological Sciences, Chiba, Japan
| | - Kazuto Masamoto
- Faculty of Informatics and Engineering, University of
Electro-Communications, Tokyo, Japan
- Center for Neuroscience and Biomedical Engineering,
University of Electro-Communications, Tokyo, Japan
- Department of Functional Brain Imaging Research,
National Institute of Radiological Sciences, Chiba, Japan
| |
Collapse
|
20
|
Sil S, Thangaraj A, Oladapo A, Hu G, Kutchy NA, Liao K, Buch S, Periyasamy P. Role of Autophagy in HIV-1 and Drug Abuse-Mediated Neuroinflammaging. Viruses 2022; 15:44. [PMID: 36680084 PMCID: PMC9866731 DOI: 10.3390/v15010044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022] Open
Abstract
Chronic low-grade inflammation remains an essential feature of HIV-1 infection under combined antiretroviral therapy (cART) and contributes to the accelerated cognitive defects and aging in HIV-1 infected populations, indicating cART limitations in suppressing viremia. Interestingly, ~50% of the HIV-1 infected population on cART that develops cognitive defects is complicated by drug abuse, involving the activation of cells in the central nervous system (CNS) and neurotoxin release, altogether leading to neuroinflammation. Neuroinflammation is the hallmark feature of many neurodegenerative disorders, including HIV-1-associated neurocognitive disorders (HAND). Impaired autophagy has been identified as one of the underlying mechanisms of HAND in treated HIV-1-infected people that also abuse drugs. Several lines of evidence suggest that autophagy regulates CNS cells' responses and maintains cellular hemostasis. The impairment of autophagy is associated with low-grade chronic inflammation and immune senescence, a known characteristic of pathological aging. Therefore, autophagy impairment due to CNS cells, such as neurons, microglia, astrocytes, and pericytes exposure to HIV-1/HIV-1 proteins, cART, and drug abuse could have combined toxicity, resulting in increased neuroinflammation, which ultimately leads to accelerated aging, referred to as neuroinflammaging. In this review, we focus on the potential role of autophagy in the mechanism of neuroinflammaging in the context of HIV-1 and drug abuse.
Collapse
Affiliation(s)
- Susmita Sil
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Annadurai Thangaraj
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Centre for Excellence in Nanobio Translational Research, Anna University, BIT Campus, Tiruchirappalli 620024, Tamil Nadu, India
| | - Abiola Oladapo
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Guoku Hu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Naseer A Kutchy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Animal Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA 90048, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Palsamy Periyasamy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| |
Collapse
|
21
|
O'Herron PJ, Hartmann DA, Xie K, Kara P, Shih AY. 3D optogenetic control of arteriole diameter in vivo. eLife 2022; 11:e72802. [PMID: 36107146 PMCID: PMC9481242 DOI: 10.7554/elife.72802] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 08/06/2022] [Indexed: 11/23/2022] Open
Abstract
Modulation of brain arteriole diameter is critical for maintaining cerebral blood pressure and controlling regional hyperemia during neural activity. However, studies of hemodynamic function in health and disease have lacked a method to control arteriole diameter independently with high spatiotemporal resolution. Here, we describe an all-optical approach to manipulate and monitor brain arteriole contractility in mice in three dimensions using combined in vivo two-photon optogenetics and imaging. The expression of the red-shifted excitatory opsin, ReaChR, in vascular smooth muscle cells enabled rapid and repeated vasoconstriction controlled by brief light pulses. Two-photon activation of ReaChR using a spatial light modulator produced highly localized constrictions when targeted to individual arterioles within the neocortex. We demonstrate the utility of this method for examining arteriole contractile dynamics and creating transient focal blood flow reductions. Additionally, we show that optogenetic constriction can be used to reshape vasodilatory responses to sensory stimulation, providing a valuable tool to dissociate blood flow changes from neural activity.
Collapse
Affiliation(s)
- Philip J O'Herron
- Department of Physiology, Augusta UniversityAugustaUnited States
- Department of Neuroscience, Medical University of South CarolinaCharlestonUnited States
| | - David A Hartmann
- Department of Neuroscience, Medical University of South CarolinaCharlestonUnited States
- Department of Neurology & Neurological Sciences, Stanford UniversityStanfordUnited States
| | - Kun Xie
- Department of Physiology, Augusta UniversityAugustaUnited States
| | - Prakash Kara
- Department of Neuroscience, Medical University of South CarolinaCharlestonUnited States
- Department of Neuroscience, University of MinnesotaMinneapolisUnited States
- Center for Magnetic Resonance Research, University of MinnesotaMinneapolisUnited States
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South CarolinaCharlestonUnited States
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research InstituteSeattleUnited States
- Department of Bioengineering, University of WashingtonSeattleUnited States
- Department of Pediatrics, University of WashingtonSeattleUnited States
| |
Collapse
|
22
|
Barkaway A, Attwell D, Korte N. Immune-vascular mural cell interactions: consequences for immune cell trafficking, cerebral blood flow, and the blood-brain barrier. NEUROPHOTONICS 2022; 9:031914. [PMID: 35581998 PMCID: PMC9107322 DOI: 10.1117/1.nph.9.3.031914] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Brain barriers are crucial sites for cerebral energy supply, waste removal, immune cell migration, and solute exchange, all of which maintain an appropriate environment for neuronal activity. At the capillary level, where the largest area of brain-vascular interface occurs, pericytes adjust cerebral blood flow (CBF) by regulating capillary diameter and maintain the blood-brain barrier (BBB) by suppressing endothelial cell (EC) transcytosis and inducing tight junction expression between ECs. Pericytes also limit the infiltration of circulating leukocytes into the brain where resident microglia confine brain injury and provide the first line of defence against invading pathogens. Brain "waste" is cleared across the BBB into the blood, phagocytosed by microglia and astrocytes, or removed by the flow of cerebrospinal fluid (CSF) through perivascular routes-a process driven by respiratory motion and the pulsation of the heart, arteriolar smooth muscle, and possibly pericytes. "Dirty" CSF exits the brain and is probably drained around olfactory nerve rootlets and via the dural meningeal lymphatic vessels and possibly the skull bone marrow. The brain is widely regarded as an immune-privileged organ because it is accessible to few antigen-primed leukocytes. Leukocytes enter the brain via the meninges, the BBB, and the blood-CSF barrier. Advances in genetic and imaging tools have revealed that neurological diseases significantly alter immune-brain barrier interactions in at least three ways: (1) the brain's immune-privileged status is compromised when pericytes are lost or lymphatic vessels are dysregulated; (2) immune cells release vasoactive molecules to regulate CBF, modulate arteriole stiffness, and can plug and eliminate capillaries which impairs CBF and possibly waste clearance; and (3) immune-vascular interactions can make the BBB leaky via multiple mechanisms, thus aggravating the influx of undesirable substances and cells. Here, we review developments in these three areas and briefly discuss potential therapeutic avenues for restoring brain barrier functions.
Collapse
Affiliation(s)
- Anna Barkaway
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - David Attwell
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Nils Korte
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| |
Collapse
|
23
|
Saiyasit N, Butlig EAR, Chaney SD, Traylor MK, Hawley NA, Randall RB, Bobinger HV, Frizell CA, Trimm F, Crook ED, Lin M, Hill BD, Keller JL, Nelson AR. Neurovascular Dysfunction in Diverse Communities With Health Disparities-Contributions to Dementia and Alzheimer's Disease. Front Neurosci 2022; 16:915405. [PMID: 35844216 PMCID: PMC9279126 DOI: 10.3389/fnins.2022.915405] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/31/2022] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease and related dementias (ADRD) are an expanding worldwide crisis. In the absence of scientific breakthroughs, the global prevalence of ADRD will continue to increase as more people are living longer. Racial or ethnic minority groups have an increased risk and incidence of ADRD and have often been neglected by the scientific research community. There is mounting evidence that vascular insults in the brain can initiate a series of biological events leading to neurodegeneration, cognitive impairment, and ADRD. We are a group of researchers interested in developing and expanding ADRD research, with an emphasis on vascular contributions to dementia, to serve our local diverse community. Toward this goal, the primary objective of this review was to investigate and better understand health disparities in Alabama and the contributions of the social determinants of health to those disparities, particularly in the context of vascular dysfunction in ADRD. Here, we explain the neurovascular dysfunction associated with Alzheimer's disease (AD) as well as the intrinsic and extrinsic risk factors contributing to dysfunction of the neurovascular unit (NVU). Next, we ascertain ethnoregional health disparities of individuals living in Alabama, as well as relevant vascular risk factors linked to AD. We also discuss current pharmaceutical and non-pharmaceutical treatment options for neurovascular dysfunction, mild cognitive impairment (MCI) and AD, including relevant studies and ongoing clinical trials. Overall, individuals in Alabama are adversely affected by social and structural determinants of health leading to health disparities, driven by rurality, ethnic minority status, and lower socioeconomic status (SES). In general, these communities have limited access to healthcare and healthy food and other amenities resulting in decreased opportunities for early diagnosis of and pharmaceutical treatments for ADRD. Although this review is focused on the current state of health disparities of ADRD patients in Alabama, future studies must include diversity of race, ethnicity, and region to best be able to treat all individuals affected by ADRD.
Collapse
Affiliation(s)
- Napatsorn Saiyasit
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Evan-Angelo R. Butlig
- Department of Neurology, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Intellectual and Developmental Disabilities Research Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - Samantha D. Chaney
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Miranda K. Traylor
- Department of Health, Kinesiology, and Sport, University of South Alabama, Mobile, AL, United States
| | - Nanako A. Hawley
- Department of Psychology, University of South Alabama, Mobile, AL, United States
| | - Ryleigh B. Randall
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Hanna V. Bobinger
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Carl A. Frizell
- Department of Physician Assistant Studies, University of South Alabama, Mobile, AL, United States
| | - Franklin Trimm
- College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Errol D. Crook
- Department of Internal Medicine, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Mike Lin
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Benjamin D. Hill
- Department of Psychology, University of South Alabama, Mobile, AL, United States
| | - Joshua L. Keller
- Department of Health, Kinesiology, and Sport, University of South Alabama, Mobile, AL, United States
| | - Amy R. Nelson
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| |
Collapse
|
24
|
Wu YT, Bennett HC, Chon U, Vanselow DJ, Zhang Q, Muñoz-Castañeda R, Cheng KC, Osten P, Drew PJ, Kim Y. Quantitative relationship between cerebrovascular network and neuronal cell types in mice. Cell Rep 2022; 39:110978. [PMID: 35732133 PMCID: PMC9271215 DOI: 10.1016/j.celrep.2022.110978] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/22/2022] [Accepted: 05/26/2022] [Indexed: 11/21/2022] Open
Abstract
The cerebrovasculature and its mural cells must meet brain regional energy demands, but how their spatial relationship with different neuronal cell types varies across the brain remains largely unknown. Here we apply brain-wide mapping methods to comprehensively define the quantitative relationships between the cerebrovasculature, capillary pericytes, and glutamatergic and GABAergic neurons, including neuronal nitric oxide synthase-positive (nNOS+) neurons and their subtypes in adult mice. Our results show high densities of vasculature with high fluid conductance and capillary pericytes in primary motor sensory cortices compared with association cortices that show significant positive and negative correlations with energy-demanding parvalbumin+ and vasomotor nNOS+ neurons, respectively. Thalamo-striatal areas that are connected to primary motor sensory cortices also show high densities of vasculature and pericytes, suggesting dense energy support for motor sensory processing areas. Our cellular-resolution resource offers opportunities to examine spatial relationships between the cerebrovascular network and neuronal cell composition in largely understudied subcortical areas.
Collapse
Affiliation(s)
- Yuan-Ting Wu
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Hannah C Bennett
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Uree Chon
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Daniel J Vanselow
- Department of Pathology, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | | | - Keith C Cheng
- Department of Pathology, The Pennsylvania State University, Hershey, PA 17033, USA
| | - Pavel Osten
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Patrick J Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA; Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA; Department of Neurosurgery, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yongsoo Kim
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA 17033, USA.
| |
Collapse
|
25
|
Korte N, Ilkan Z, Pearson CL, Pfeiffer T, Singhal P, Rock JR, Sethi H, Gill D, Attwell D, Tammaro P. The Ca2+-gated channel TMEM16A amplifies capillary pericyte contraction and reduces cerebral blood flow after ischemia. J Clin Invest 2022; 132:e154118. [PMID: 35316222 PMCID: PMC9057602 DOI: 10.1172/jci154118] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/16/2022] [Indexed: 11/26/2022] Open
Abstract
Pericyte-mediated capillary constriction decreases cerebral blood flow in stroke after an occluded artery is unblocked. The determinants of pericyte tone are poorly understood. We show that a small rise in cytoplasmic Ca2+ concentration ([Ca2+]i) in pericytes activated chloride efflux through the Ca2+-gated anion channel TMEM16A, thus depolarizing the cell and opening voltage-gated calcium channels. This mechanism strongly amplified the pericyte [Ca2+]i rise and capillary constriction evoked by contractile agonists and ischemia. In a rodent stroke model, TMEM16A inhibition slowed the ischemia-evoked pericyte [Ca2+]i rise, capillary constriction, and pericyte death; reduced neutrophil stalling; and improved cerebrovascular reperfusion. Genetic analysis implicated altered TMEM16A expression in poor patient recovery from ischemic stroke. Thus, pericyte TMEM16A is a crucial regulator of cerebral capillary function and a potential therapeutic target for stroke and possibly other disorders of impaired microvascular flow, such as Alzheimer's disease and vascular dementia.
Collapse
Affiliation(s)
- Nils Korte
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Zeki Ilkan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Claire L. Pearson
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Prabhav Singhal
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Jason R. Rock
- Center for Regenerative Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Huma Sethi
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Dipender Gill
- Department of Epidemiology and Biostatistics, St Mary’s Hospital, Imperial College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Paolo Tammaro
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
26
|
Silva NCBS, Bracko O, Nelson AR, de Oliveira FF, Robison LS, Shaaban CE, Hainsworth AH, Price BR. Vascular cognitive impairment and dementia: An early career researcher perspective. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2022; 14:e12310. [PMID: 35496373 PMCID: PMC9043906 DOI: 10.1002/dad2.12310] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/16/2022] [Accepted: 03/22/2022] [Indexed: 01/07/2023]
Abstract
The field of vascular contributions to cognitive impairment and dementia (VCID) is evolving rapidly. Research in VCID encompasses topics aiming to understand, prevent, and treat the detrimental effects of vascular disease burden in the human brain. In this perspective piece, early career researchers (ECRs) in the field provide an overview of VCID, discuss past and present efforts, and highlight priorities for future research. We emphasize the following critical points as the field progresses: (a) consolidate existing neuroimaging and fluid biomarkers, and establish their utility for pharmacological and non-pharmacological interventions; (b) develop new biomarkers, and new non-clinical models that better recapitulate vascular pathologies; (c) amplify access to emerging biomarker and imaging techniques; (d) validate findings from previous investigations in diverse populations, including those at higher risk of cognitive impairment (e.g., Black, Hispanic, and Indigenous populations); and (e) conduct randomized controlled trials within diverse populations with well-characterized vascular pathologies emphasizing clinically meaningful outcomes.
Collapse
Affiliation(s)
- Nárlon C. Boa Sorte Silva
- Djavad Mowafaghian Centre for Brain HealthDepartment of Physical TherapyFaculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Oliver Bracko
- Department of BiologyThe University of MiamiCoral GablesFloridaUSA
| | - Amy R. Nelson
- Department of Physiology and Cell BiologyUniversity of South AlabamaMobileAlabamaUSA
| | | | - Lisa S. Robison
- Department of Psychology and NeuroscienceNova Southeastern UniversityFort LauderdaleFloridaUSA
| | | | - Atticus H. Hainsworth
- Molecular & Clinical Sciences Research InstituteSt George's University of London, UKDepartment of NeurologySt George's University Hospitals NHS Foundation Trust LondonLondonUK
| | - Brittani R. Price
- Department of NeuroscienceTufts University School of MedicineBostonMassachusettsUSA
| |
Collapse
|
27
|
Nelson AR. Peripheral Pathways to Neurovascular Unit Dysfunction, Cognitive Impairment, and Alzheimer’s Disease. Front Aging Neurosci 2022; 14:858429. [PMID: 35517047 PMCID: PMC9062225 DOI: 10.3389/fnagi.2022.858429] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/03/2022] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia. It was first described more than a century ago, and scientists are acquiring new data and learning novel information about the disease every day. Although there are nuances and details continuously being unraveled, many key players were identified in the early 1900’s by Dr. Oskar Fischer and Dr. Alois Alzheimer, including amyloid-beta (Aβ), tau, vascular abnormalities, gliosis, and a possible role of infections. More recently, there has been growing interest in and appreciation for neurovascular unit dysfunction that occurs early in mild cognitive impairment (MCI) before and independent of Aβ and tau brain accumulation. In the last decade, evidence that Aβ and tau oligomers are antimicrobial peptides generated in response to infection has expanded our knowledge and challenged preconceived notions. The concept that pathogenic germs cause infections generating an innate immune response (e.g., Aβ and tau produced by peripheral organs) that is associated with incident dementia is worthwhile considering in the context of sporadic AD with an unknown root cause. Therefore, the peripheral amyloid hypothesis to cognitive impairment and AD is proposed and remains to be vetted by future research. Meanwhile, humans remain complex variable organisms with individual risk factors that define their immune status, neurovascular function, and neuronal plasticity. In this focused review, the idea that infections and organ dysfunction contribute to Alzheimer’s disease, through the generation of peripheral amyloids and/or neurovascular unit dysfunction will be explored and discussed. Ultimately, many questions remain to be answered and critical areas of future exploration are highlighted.
Collapse
|
28
|
Wang Y, Kisler K, Nikolakopoulou AM, Fernandez JA, Griffin JH, Zlokovic BV. 3K3A-Activated Protein C Protects the Blood-Brain Barrier and Neurons From Accelerated Ischemic Injury Caused by Pericyte Deficiency in Mice. Front Neurosci 2022; 16:841916. [PMID: 35431776 PMCID: PMC9005806 DOI: 10.3389/fnins.2022.841916] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/16/2022] [Indexed: 11/16/2022] Open
Abstract
Pericytes, mural cells of brain capillaries, maintain the blood-brain barrier (BBB), regulate cerebral blood flow (CBF), and protect neurons against ischemic damage. To further investigate the role of pericytes in ischemia, we induced stroke by 45-min transient middle cerebral artery occlusion (tMCAo) in 6-month-old pericyte-deficient Pdgfrb + /- mice and control Pdgfrb+/+ littermates. Compared to controls, Pdgfrb + /- mice showed a 26% greater loss of CBF during early reperfusion, and 40-50% increase in the infarct and edema volumes and motor neurological score 24 h after tMCAo. These changes were accompanied by 50% increase in both immunoglobulin G and fibrinogen pericapillary deposits in the ischemic cortex 8 h after tMCAo indicating an accelerated BBB breakdown, and 35 and 55% greater losses of pericyte coverage and number of degenerating neurons 24 h after tMCAo, respectively. Treatment of Pdgfrb + /- mice with 3K3A-activated protein C (APC), a cell-signaling analog of plasma protease APC, administered intravenously 10 min and 4 h after tMCAo normalized CBF during the early reperfusion phase and reduced infarct and edema volume and motor neurological score by 55-60%, with similar reductions in BBB breakdown and number of degenerating neurons. Our data suggest that pericyte deficiency results in greater brain injury, BBB breakdown, and neuronal degeneration in stroked mice and that 3K3A-APC protects the brain from accelerated injury caused by pericyte deficiency. These findings may have implications for treatment of ischemic brain injury in neurological conditions associated with pericyte loss such as those seen during normal aging and in neurodegenerative disorders such as Alzheimer's disease.
Collapse
Affiliation(s)
- Yaoming Wang
- Department of Physiology and Neuroscience, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, United States
| | - Kassandra Kisler
- Department of Physiology and Neuroscience, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, United States
| | - Angeliki Maria Nikolakopoulou
- Department of Physiology and Neuroscience, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, United States
| | - Jose A. Fernandez
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - John H. Griffin
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
- Division of Hematology/Oncology, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, United States
| |
Collapse
|
29
|
Mirzayi P, Shobeiri P, Kalantari A, Perry G, Rezaei N. Optogenetics: implications for Alzheimer's disease research and therapy. Mol Brain 2022; 15:20. [PMID: 35197102 PMCID: PMC8867657 DOI: 10.1186/s13041-022-00905-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/10/2022] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD), a critical neurodegenerative condition, has a wide range of effects on brain activity. Synaptic plasticity and neuronal circuits are the most vulnerable in Alzheimer’s disease, but the exact mechanism is unknown. Incorporating optogenetics into the study of AD has resulted in a significant leap in this field during the last decades, kicking off a revolution in our knowledge of the networks that underpin cognitive functions. In Alzheimer's disease, optogenetics can help to reduce and reverse neural circuit and memory impairments. Here we review how optogenetically driven methods have helped expand our knowledge of Alzheimer's disease, and how optogenetic interventions hint at a future translation into therapeutic possibilities for further utilization in clinical settings. In conclusion, neuroscience has witnessed one of its largest revolutions following the introduction of optogenetics into the field.
Collapse
Affiliation(s)
- Parsa Mirzayi
- School of Medicine, Tehran University of Medical Sciences (TUMS), Children's Medical Center Hospital, Dr. Qarib St., Keshavarz Blvd, 14194, Tehran, Iran.,Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Parnian Shobeiri
- School of Medicine, Tehran University of Medical Sciences (TUMS), Children's Medical Center Hospital, Dr. Qarib St., Keshavarz Blvd, 14194, Tehran, Iran.,Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran.,Non-Communicable Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Amirali Kalantari
- School of Medicine, Tehran University of Medical Sciences (TUMS), Children's Medical Center Hospital, Dr. Qarib St., Keshavarz Blvd, 14194, Tehran, Iran.,Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - George Perry
- Department of Biology and Neurosciences Institute, University of Texas at San Antonio (UTSA), San Antonio, TX, USA
| | - Nima Rezaei
- Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran. .,Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. .,Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. .,Research Center for Immunodeficiencies, Children's Medical Center, Dr. Gharib St, Keshavarz Blvd, Tehran, Iran.
| |
Collapse
|
30
|
Stefan S, Kim A, Marchand PJ, Lesage F, Lee J. Deep Learning and Simulation for the Estimation of Red Blood Cell Flux With Optical Coherence Tomography. Front Neurosci 2022; 16:835773. [PMID: 35250467 PMCID: PMC8891630 DOI: 10.3389/fnins.2022.835773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
We present a deep learning and simulation-based method to measure cortical capillary red blood cell (RBC) flux using Optical Coherence Tomography (OCT). This method is more accurate than the traditional peak-counting method and avoids any user parametrization, such as a threshold choice. We used data that was simultaneously acquired using OCT and two-photon microscopy to uncover the distribution of parameters governing the height, width, and inter-peak time of peaks in OCT intensity associated with the passage of RBCs. This allowed us to simulate thousands of time-series examples for different flux values and signal-to-noise ratios, which we then used to train a 1D convolutional neural network (CNN). The trained CNN enabled robust measurement of RBC flux across the entire network of hundreds of capillaries.
Collapse
Affiliation(s)
- Sabina Stefan
- School of Engineering, Brown University, Providence, RI, United States
| | - Anna Kim
- Department of Neuroscience, Brown University, Providence, RI, United States
| | - Paul J. Marchand
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC, Canada
| | - Frederic Lesage
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC, Canada
| | - Jonghwan Lee
- School of Engineering, Brown University, Providence, RI, United States
- Carney Institute for Brain Science, Brown University, Providence, RI, United States
- *Correspondence: Jonghwan Lee,
| |
Collapse
|
31
|
Pericyte dysfunction and loss of interpericyte tunneling nanotubes promote neurovascular deficits in glaucoma. Proc Natl Acad Sci U S A 2022; 119:2110329119. [PMID: 35135877 PMCID: PMC8851476 DOI: 10.1073/pnas.2110329119] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2021] [Indexed: 12/14/2022] Open
Abstract
Reduced blood flow and impaired neurovascular coupling are recognized features of glaucoma, the leading cause of irreversible blindness worldwide, but the mechanisms underlying these defects are unknown. Retinal pericytes regulate microcirculatory blood flow and coordinate neurovascular coupling through interpericyte tunneling nanotubes (IP-TNTs). Using two-photon microscope live imaging of the mouse retina, we found reduced capillary diameter and impaired blood flow at pericyte locations in eyes with high intraocular pressure, the most important risk factor to develop glaucoma. We show that IP-TNTs are structurally and functionally damaged by ocular hypertension, a response that disrupted light-evoked neurovascular coupling. Pericyte-specific inhibition of excessive Ca2+ influx rescued hemodynamic responses, protected IP-TNTs and neurovascular coupling, and enhanced retinal neuronal function as well as survival in glaucomatous retinas. Our study identifies pericytes and IP-TNTs as potential therapeutic targets to counter ocular pressure-related microvascular deficits, and provides preclinical proof of concept that strategies aimed to restore intrapericyte calcium homeostasis rescue autoregulatory blood flow and prevent neuronal dysfunction.
Collapse
|
32
|
Hartmann DA, Coelho-Santos V, Shih AY. Pericyte Control of Blood Flow Across Microvascular Zones in the Central Nervous System. Annu Rev Physiol 2022; 84:331-354. [PMID: 34672718 PMCID: PMC10480047 DOI: 10.1146/annurev-physiol-061121-040127] [Citation(s) in RCA: 82] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The vast majority of the brain's vascular length is composed of capillaries, where our understanding of blood flow control remains incomplete. This review synthesizes current knowledge on the control of blood flow across microvascular zones by addressing issues with nomenclature and drawing on new developments from in vivo optical imaging and single-cell transcriptomics. Recent studies have highlighted important distinctions in mural cell morphology, gene expression, and contractile dynamics, which can explain observed differences in response to vasoactive mediators between arteriole, transitional, and capillary zones. Smooth muscle cells of arterioles and ensheathing pericytes of the arteriole-capillary transitional zone control large-scale, rapid changes in blood flow. In contrast, capillary pericytes downstream of the transitional zone act on slower and smaller scales and are involved in establishing resting capillary tone and flow heterogeneity. Many unresolved issues remain, including the vasoactive mediators that activate the different pericyte types in vivo, the role of pericyte-endothelial communication in conducting signals from capillaries to arterioles, and how neurological disease affects these mechanisms.
Collapse
Affiliation(s)
- David A Hartmann
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
| | - Vanessa Coelho-Santos
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA;
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA;
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| |
Collapse
|
33
|
Clark AT, Abrahamson EE, Harper MM, Ikonomovic MD. Chronic effects of blast injury on the microvasculature in a transgenic mouse model of Alzheimer's disease related Aβ amyloidosis. Fluids Barriers CNS 2022; 19:5. [PMID: 35012589 PMCID: PMC8751260 DOI: 10.1186/s12987-021-00301-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/22/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Altered cerebrovascular function and accumulation of amyloid-β (Aβ) after traumatic brain injury (TBI) can contribute to chronic neuropathology and increase the risk for Alzheimer's disease (AD). TBI due to a blast-induced shock wave (bTBI) adversely affects the neurovascular unit (NVU) during the acute period after injury. However, the chronic effects of bTBI and Aβ on cellular components of the NVU and capillary network are not well understood. METHODS We exposed young adult (age range: 76-106 days) female transgenic (Tg) APP/PS1 mice, a model of AD-like Aβ amyloidosis, and wild type (Wt) mice to a single bTBI (~ 138 kPa or ~ 20 psi) or to a Sham procedure. At 3-months or 12-months survival after exposure, we quantified neocortical Aβ load in Tg mice, and percent contact area between aquaporin-4 (AQP4)-immunoreactive astrocytic end-feet and brain capillaries, numbers of PDGFRβ-immunoreactive pericytes, and capillary densities in both genotypes. RESULTS The astroglia AQP4-capillary contact area in the Tg-bTBI group was significantly lower than in the Tg-Sham group at 3-months survival. No significant changes in the AQP4-capillary contact area were observed in the Tg-bTBI group at 12-months survival or in the Wt groups. Capillary density in the Tg-bTBI group at 12-months survival was significantly higher compared to the Tg-Sham control and to the Tg-bTBI 3-months survival group. The Wt-bTBI group had significantly lower capillary density and pericyte numbers at 12-months survival compared to 3-months survival. When pericytes were quantified relative to capillary density, no significant differences were detected among the experimental groups, for both genotypes. CONCLUSION In conditions of high brain concentrations of human Aβ, bTBI exposure results in reduced AQP4 expression at the astroglia-microvascular interface, and in chronic capillary proliferation like what has been reported in AD. Long term microvascular changes after bTBI may contribute to the risk for developing chronic neurodegenerative disease later in life.
Collapse
Affiliation(s)
- Alexander T. Clark
- Department of Neurology, University of Pittsburgh School of Medicine, 3471 Fifth Ave, Pittsburgh, PA 15213 USA
| | - Eric E. Abrahamson
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University Drive C, Pittsburgh, PA 15240 USA
- Department of Neurology, University of Pittsburgh School of Medicine, 3471 Fifth Ave, Pittsburgh, PA 15213 USA
| | - Matthew M. Harper
- The Iowa City VA Center for the Prevention and Treatment of Visual Loss, 601 Hwy 6 West, Iowa City, IA 52246 USA
- Department of Ophthalmology and Visual Sciences and Biology, University of Iowa, 200 Hawkins Dr, Iowa City, IA 52242 USA
| | - Milos D. Ikonomovic
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, University Drive C, Pittsburgh, PA 15240 USA
- Department of Neurology, University of Pittsburgh School of Medicine, 3471 Fifth Ave, Pittsburgh, PA 15213 USA
- Department of Psychiatry, University of Pittsburgh School of Medicine, Thomas Detre Hall of the WPH, Room 1421, 3811 O’Hara Street, Pittsburgh, PA 15213-2593 USA
| |
Collapse
|
34
|
McConnell HL, Mishra A. Cells of the Blood-Brain Barrier: An Overview of the Neurovascular Unit in Health and Disease. Methods Mol Biol 2022; 2492:3-24. [PMID: 35733036 PMCID: PMC9987262 DOI: 10.1007/978-1-0716-2289-6_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
The brain is endowed with highly specialized vasculature that is both structurally and functionally unique compared to vasculature supplying peripheral organs. The blood-brain barrier (BBB) is formed by endothelial cells of the cerebral vasculature and prevents extravasation of blood products into the brain to protect neural tissue and maintain a homeostatic environment. The BBB functions as part of the neurovascular unit (NVU), which is composed of neurons, astrocytes, and microglia in addition to the specialized endothelial cells, mural cells, and the basement membrane. Through coordinated intercellular signaling, these cells function as a dynamic unit to tightly regulate brain blood flow, vascular function, neuroimmune responses, and waste clearance. In this chapter, we review the functions of individual NVU components, describe neurovascular coupling as a classic example of NVU function, and discuss archetypal NVU pathophysiology during disease.
Collapse
Affiliation(s)
- Heather L McConnell
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
- Office of Academic Development, Houston Methodist Research Institute, Houston, TX, USA
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
| |
Collapse
|
35
|
Michau A, Lafont C, Bargi-Souza P, Kemkem Y, Guillou A, Ravier MA, Bertrand G, Varrault A, Fiordelisio T, Hodson DJ, Mollard P, Schaeffer M. Metabolic Stress Impairs Pericyte Response to Optogenetic Stimulation in Pancreatic Islets. Front Endocrinol (Lausanne) 2022; 13:918733. [PMID: 35813647 PMCID: PMC9259887 DOI: 10.3389/fendo.2022.918733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Pancreatic islets are highly vascularized micro-organs ensuring whole body glucose homeostasis. Islet vascular cells play an integral part in sustaining adequate insulin release by beta cells. In particular, recent studies have demonstrated that islet pericytes regulate local blood flow velocity and are required for maintenance of beta cell maturity and function. In addition, increased metabolic demand accompanying obesity alters islet pericyte morphology. Here, we sought to explore the effects of metabolic stress on islet pericyte functional response to stimulation in a mouse model of type 2 diabetes, directly in the pancreas in vivo . We found that high fat diet induced islet pericyte hypertrophy without alterations in basal local blood flow. However, optogenetic stimulation of pericyte activity revealed impaired islet vascular responses, despite increased expression of genes encoding proteins directly or indirectly involved in cell contraction. These findings suggest that metabolic stress impinges upon islet pericyte function, which may contribute to beta cell failure during T2D.
Collapse
Affiliation(s)
- Aurélien Michau
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Chrystel Lafont
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Paula Bargi-Souza
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
- Department of Physiology and Biophysics of the Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Yasmine Kemkem
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Anne Guillou
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Magalie A. Ravier
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Gyslaine Bertrand
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Annie Varrault
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Tatiana Fiordelisio
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
- Laboratorio de Neuroendocrinología Comparada, Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - David J. Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), National Institute for Health and Care Research (NIHR) Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Patrice Mollard
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Marie Schaeffer
- Institute of Functional Genomics, Univ. Montpellier, CNRS, INSERM, Montpellier, France
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Univ Montpellier, Montpellier, France
- *Correspondence: Marie Schaeffer,
| |
Collapse
|
36
|
Contribution of animal models toward understanding resting state functional connectivity. Neuroimage 2021; 245:118630. [PMID: 34644593 DOI: 10.1016/j.neuroimage.2021.118630] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/06/2021] [Accepted: 09/29/2021] [Indexed: 12/27/2022] Open
Abstract
Functional connectivity, which reflects the spatial and temporal organization of intrinsic activity throughout the brain, is one of the most studied measures in human neuroimaging research. The noninvasive acquisition of resting state functional magnetic resonance imaging (rs-fMRI) allows the characterization of features designated as functional networks, functional connectivity gradients, and time-varying activity patterns that provide insight into the intrinsic functional organization of the brain and potential alterations related to brain dysfunction. Functional connectivity, hence, captures dimensions of the brain's activity that have enormous potential for both clinical and preclinical research. However, the mechanisms underlying functional connectivity have yet to be fully characterized, hindering interpretation of rs-fMRI studies. As in other branches of neuroscience, the identification of the neurophysiological processes that contribute to functional connectivity largely depends on research conducted on laboratory animals, which provide a platform where specific, multi-dimensional investigations that involve invasive measurements can be carried out. These highly controlled experiments facilitate the interpretation of the temporal correlations observed across the brain. Indeed, information obtained from animal experimentation to date is the basis for our current understanding of the underlying basis for functional brain connectivity. This review presents a compendium of some of the most critical advances in the field based on the efforts made by the animal neuroimaging community.
Collapse
|
37
|
Guerrero A, De Strooper B, Arancibia-Cárcamo IL. Cellular senescence at the crossroads of inflammation and Alzheimer's disease. Trends Neurosci 2021; 44:714-727. [PMID: 34366147 DOI: 10.1016/j.tins.2021.06.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/14/2022]
Abstract
Aging is a key risk factor for Alzheimer's disease (AD), but the reasons for this association are not well understood. Senescent cells accumulate in aged tissues and have been shown to play causal roles in age-related pathologies through their proinflammatory secretome. The question arises whether senescence-induced inflammation might contribute to AD and bridge the gap between aging and AD. Here, we highlight the role of cellular senescence as a driver of the aging phenotype, and discuss the current evidence that connects senescence with AD and neurodegeneration.
Collapse
Affiliation(s)
- Ana Guerrero
- UK Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK; The Francis Crick Institute, London NW1 1AT, UK
| | - Bart De Strooper
- UK Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK; The Francis Crick Institute, London NW1 1AT, UK; Department of Neurosciences, Leuven Brain Institute, Katholieke Universiteit (KU) Leuven, Leuven, Belgium; Vlaams Instituut voor Biotechnologie (VIB) Centre for Brain and Disease Research, Leuven, Belgium
| | - I Lorena Arancibia-Cárcamo
- UK Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK; The Francis Crick Institute, London NW1 1AT, UK.
| |
Collapse
|
38
|
Precapillary sphincters and pericytes at first-order capillaries as key regulators for brain capillary perfusion. Proc Natl Acad Sci U S A 2021; 118:2023749118. [PMID: 34155102 DOI: 10.1073/pnas.2023749118] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rises in local neural activity trigger local increases of cerebral blood flow, which is essential to match local energy demands. However, the specific location of microvascular flow control is incompletely understood. Here, we used two-photon microscopy to observe brain microvasculature in vivo. Small spatial movement of a three-dimensional (3D) vasculature makes it challenging to precisely measure vessel diameter at a single x-y plane. To overcome this problem, we carried out four-dimensional (x-y-z-t) imaging of brain microvessels during exposure to vasoactive molecules in order to constrain the impact of brain movements on the recordings. We demonstrate that rises in synaptic activity, acetylcholine, nitric oxide, cyclic guanosine monophosphate, ATP-sensitive potassium channels, and endothelin-1 exert far greater effects on brain precapillary sphincters and first-order capillaries than on penetrating arterioles or downstream capillaries, but with similar kinetics. The high level of responsiveness at precapillary sphincters and first-order capillaries was matched by a higher level of α-smooth muscle actin in pericytes as compared to penetrating arterioles and downstream capillaries. Mathematical modeling based on 3D vasculature reconstruction showed that precapillary sphincters predominantly regulate capillary blood flow and pressure as compared to penetrating arterioles and downstream capillaries. Our results confirm a key role for precapillary sphincters and pericytes on first-order capillaries as sensors and effectors of endothelium- or brain-derived vascular signals.
Collapse
|
39
|
Cao L, Zhou Y, Chen M, Li L, Zhang W. Pericytes for Therapeutic Approaches to Ischemic Stroke. Front Neurosci 2021; 15:629297. [PMID: 34239409 PMCID: PMC8259582 DOI: 10.3389/fnins.2021.629297] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 05/11/2021] [Indexed: 12/18/2022] Open
Abstract
Pericytes are perivascular multipotent cells located on capillaries. Although pericytes are discovered in the nineteenth century, recent studies have found that pericytes play an important role in maintaining the blood—brain barrier (BBB) and regulating the neurovascular system. In the neurovascular unit, pericytes perform their functions by coordinating the crosstalk between endothelial, glial, and neuronal cells. Dysfunction of pericytes can lead to a variety of diseases, including stroke and other neurological disorders. Recent studies have suggested that pericytes can serve as a therapeutic target in ischemic stroke. In this review, we first summarize the biology and functions of pericytes in the central nervous system. Then, we focus on the role of dysfunctional pericytes in the pathogenesis of ischemic stroke. Finally, we discuss new therapies for ischemic stroke based on targeting pericytes.
Collapse
Affiliation(s)
- Lu Cao
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yanbo Zhou
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Mengguang Chen
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Li Li
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Wei Zhang
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| |
Collapse
|
40
|
Alkayed NJ, Cipolla MJ. Vascular Biology. Stroke 2021; 52:2440-2441. [PMID: 34078110 DOI: 10.1161/strokeaha.121.033556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nabil J Alkayed
- Department of Anesthesiology and Perioperative Medicine, Portland, OR (N.J.A.)
| | - Marilyn J Cipolla
- Department of Neurological Science, University of Vermont Larner College of Medicine, Burlington (M.J.C.)
| |
Collapse
|
41
|
Brain capillary pericytes exert a substantial but slow influence on blood flow. Nat Neurosci 2021; 24:633-645. [PMID: 33603231 PMCID: PMC8102366 DOI: 10.1038/s41593-020-00793-2] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 12/23/2020] [Indexed: 01/30/2023]
Abstract
The majority of the brain's vasculature is composed of intricate capillary networks lined by capillary pericytes. However, it remains unclear whether capillary pericytes influence blood flow. Using two-photon microscopy to observe and manipulate brain capillary pericytes in vivo, we find that their optogenetic stimulation decreases lumen diameter and blood flow, but with slower kinetics than similar stimulation of mural cells on upstream pial and precapillary arterioles. This slow vasoconstriction was inhibited by the clinically used vasodilator fasudil, a Rho-kinase inhibitor that blocks contractile machinery. Capillary pericytes were also slower to constrict back to baseline following hypercapnia-induced dilation, and slower to dilate towards baseline following optogenetically induced vasoconstriction. Optical ablation of single capillary pericytes led to sustained local dilation and a doubling of blood cell flux selectively in capillaries lacking pericyte contact. These data indicate that capillary pericytes contribute to basal blood flow resistance and slow modulation of blood flow throughout the brain.
Collapse
|
42
|
Bennett HC, Kim Y. Pericytes Across the Lifetime in the Central Nervous System. Front Cell Neurosci 2021; 15:627291. [PMID: 33776651 PMCID: PMC7994897 DOI: 10.3389/fncel.2021.627291] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/23/2021] [Indexed: 12/25/2022] Open
Abstract
The pericyte is a perivascular cell type that encapsulates the microvasculature of the brain and spinal cord. Pericytes play a crucial role in the development and maintenance of the blood-brain barrier (BBB) and have a multitude of important functions in the brain. Recent evidence indicates that pericyte impairment has been implicated in neurovascular pathology associated with various human diseases such as diabetes mellitus, Alzheimer's disease (AD), and stroke. Although the pericyte is essential for normal brain function, knowledge about its developmental trajectory and anatomical distribution is limited. This review article summarizes the scientific community's current understanding of pericytes' regional heterogeneity in the brain and their changes during major life stages. More specifically, this review article focuses on pericyte differentiation and migration during brain development, regional population differences in the adult brain, and changes during normal and pathological aging. Most of what is known about pericytes come from studies of the cerebral cortex and hippocampus. Therefore, we highlight the need to expand our understanding of pericyte distribution and function in the whole brain to better delineate this cell type's role in the normal brain and pathological conditions.
Collapse
Affiliation(s)
- Hannah C Bennett
- Department of Neural and Behavioral Sciences, Penn State University, Hershey, PA, United States
| | - Yongsoo Kim
- Department of Neural and Behavioral Sciences, Penn State University, Hershey, PA, United States
| |
Collapse
|
43
|
Pfeiffer T, Li Y, Attwell D. Diverse mechanisms regulating brain energy supply at the capillary level. Curr Opin Neurobiol 2021; 69:41-50. [PMID: 33485189 DOI: 10.1016/j.conb.2020.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/28/2020] [Accepted: 12/13/2020] [Indexed: 02/06/2023]
Abstract
Neural information processing depends critically on the brain's energy supply, which is provided in the form of glucose and oxygen in the blood. Regulation of this supply occurs by smooth muscle and contractile pericytes adjusting the diameter of arterioles and capillaries, respectively. Controversies exist over the relative importance of capillary and arteriolar level control, whether enzymatically generated signals or K+ ions are the dominant controller of cerebral blood flow, and the involvement of capillary endothelial cells. Here, we try to synthesise the relevant recent data into a coherent view of how brain energy supply is controlled and suggest approaches to answering key questions.
Collapse
Affiliation(s)
- Thomas Pfeiffer
- Department of Neuroscience, Physiology & Pharmacology, University College London Gower Street, London, WC1E 6BT, UK.
| | - Yuening Li
- Department of Neuroscience, Physiology & Pharmacology, University College London Gower Street, London, WC1E 6BT, UK
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London Gower Street, London, WC1E 6BT, UK.
| |
Collapse
|
44
|
Howarth C, Mishra A, Hall CN. More than just summed neuronal activity: how multiple cell types shape the BOLD response. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190630. [PMID: 33190598 PMCID: PMC7116385 DOI: 10.1098/rstb.2019.0630] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Functional neuroimaging techniques are widely applied to investigations of human cognition and disease. The most commonly used among these is blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. The BOLD signal occurs because neural activity induces an increase in local blood supply to support the increased metabolism that occurs during activity. This supply usually outmatches demand, resulting in an increase in oxygenated blood in an active brain region, and a corresponding decrease in deoxygenated blood, which generates the BOLD signal. Hence, the BOLD response is shaped by an integration of local oxygen use, through metabolism, and supply, in the blood. To understand what information is carried in BOLD signals, we must understand how several cell types in the brain-local excitatory neurons, inhibitory neurons, astrocytes and vascular cells (pericytes, vascular smooth muscle and endothelial cells), and their modulation by ascending projection neurons-contribute to both metabolism and haemodynamic changes. Here, we review the contributions of each cell type to the regulation of cerebral blood flow and metabolism, and discuss situations where a simplified interpretation of the BOLD response as reporting local excitatory activity may misrepresent important biological phenomena, for example with regards to arousal states, ageing and neurological disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
Collapse
Affiliation(s)
- Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, and Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | | |
Collapse
|
45
|
Crumpler R, Roman RJ, Fan F. Capillary Stalling: A Mechanism of Decreased Cerebral Blood Flow in AD/ADRD. JOURNAL OF EXPERIMENTAL NEUROLOGY 2021; 2:149-153. [PMID: 35028643 PMCID: PMC8754422 DOI: 10.33696/neurol.2.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alzheimer's Disease (AD) and Alzheimer's Disease-Related Dementias (ADRD) are debilitating conditions that are highly associated with aging populations, especially those with comorbidities such as diabetes and hypertension. In addition to the classical pathological findings of AD, such as beta-amyloid (Aβ) accumulation and tau hyperphosphorylation, vascular dysfunction is also associated with the progression of the disease. Vascular dysfunction in AD is associated with decreased cerebral blood flow (CBF). Impaired CBF is an early and persistent symptom of AD/ADRD and is thought to be associated with deficient autoregulation and neurovascular coupling. Another recently elucidated mechanism that contributes to cerebral hypoperfusion is capillary stalling, or the temporary arrest of capillary blood flow usually precipitated by a stalled leukocyte or constriction of actin-containing capillary pericytes. Stalled capillaries are associated with decreased CBF and impaired cognitive performance. AD/ADRD are associated with chronic, low-level inflammation, which contributes to capillary stalling by increased cell adhesion molecules, circulating leukocytes, and reactive oxygen species production. Recent research has shed light on potential targets to decrease capillary stalling in AD mice. Separate inhibition of Ly6G and VEGF-A has been shown to decrease capillary stalling and increase CBF in AD mice. These results suggest that targeting stalled capillaries could influence the outcome of AD and potentially be a target for future therapies.
Collapse
Affiliation(s)
- Reece Crumpler
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| |
Collapse
|
46
|
Imaging and optogenetic modulation of vascular mural cells in the live brain. Nat Protoc 2020; 16:472-496. [PMID: 33299155 DOI: 10.1038/s41596-020-00425-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022]
Abstract
Mural cells (smooth muscle cells and pericytes) are integral components of brain blood vessels that play important roles in vascular formation, blood-brain barrier maintenance, and regulation of regional cerebral blood flow (rCBF). These cells are implicated in conditions ranging from developmental vascular disorders to age-related neurodegenerative diseases. Here we present complementary tools for cell labeling with transgenic mice and organic dyes that allow high-resolution intravital imaging of the different mural cell subtypes. We also provide detailed methodologies for imaging of spontaneous and neural activity-evoked calcium transients in mural cells. In addition, we describe strategies for single- and two-photon optogenetics that allow manipulation of the activity of individual and small clusters of mural cells. Together with measurements of diameter and flow in individual brain microvessels, calcium imaging and optogenetics allow the investigation of pericyte and smooth muscle cell physiology and their role in regulating rCBF. We also demonstrate the utility of these tools to investigate mural cells in the context of Alzheimer's disease and cerebral ischemia mouse models. Thus, these methods can be used to reveal the functional and structural heterogeneity of mural cells in vivo, and allow detailed cellular studies of the normal function and pathophysiology of mural cells in a variety of disease models. The implementation of this protocol can take from several hours to days depending on the intended applications.
Collapse
|
47
|
Beard DJ, Brown LS, Sutherland BA. The rise of pericytes in neurovascular research. J Cereb Blood Flow Metab 2020; 40:2366-2373. [PMID: 32955956 PMCID: PMC7820692 DOI: 10.1177/0271678x20958497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/06/2020] [Accepted: 08/16/2020] [Indexed: 01/05/2023]
Abstract
The popularity of pericyte research is increasing, and this was not more evident than at the recent 2019 Brain meeting in Yokohama which featured a large number of presentations focused on brain pericyte research, including the Presidential Symposium. In this article, we will provide a history of brain pericyte research, present the results of our analysis showing a substantial increase in brain pericyte research presented at Brain meetings since 2005, suggest reasons for their increased popularity, and comment on what the future holds for brain pericyte research.
Collapse
Affiliation(s)
- Daniel J Beard
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Lachlan S Brown
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
| | - Brad A Sutherland
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Australia
| |
Collapse
|
48
|
Korte N, Nortley R, Attwell D. Cerebral blood flow decrease as an early pathological mechanism in Alzheimer's disease. Acta Neuropathol 2020; 140:793-810. [PMID: 32865691 PMCID: PMC7666276 DOI: 10.1007/s00401-020-02215-w] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/15/2020] [Accepted: 08/15/2020] [Indexed: 02/08/2023]
Abstract
Therapies targeting late events in Alzheimer's disease (AD), including aggregation of amyloid beta (Aβ) and hyperphosphorylated tau, have largely failed, probably because they are given after significant neuronal damage has occurred. Biomarkers suggest that the earliest event in AD is a decrease of cerebral blood flow (CBF). This is caused by constriction of capillaries by contractile pericytes, probably evoked by oligomeric Aβ. CBF is also reduced by neutrophil trapping in capillaries and clot formation, perhaps secondary to the capillary constriction. The fall in CBF potentiates neurodegeneration by upregulating the BACE1 enzyme that makes Aβ and by promoting tau hyperphosphorylation. Surprisingly, therefore, CBF reduction may play a crucial role in driving cognitive decline by initiating the amyloid cascade itself, or being caused by and amplifying Aβ production. Here, we review developments in this area that are neglected in current approaches to AD, with the aim of promoting novel mechanism-based therapeutic approaches.
Collapse
Affiliation(s)
- Nils Korte
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Ross Nortley
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| |
Collapse
|
49
|
Robert J, Weilinger NL, Cao LP, Cataldi S, Button EB, Stukas S, Martin EM, Seibler P, Gilmour M, Caffrey TM, Rowe EM, Fan J, MacVicar B, Farrer MJ, Wellington CL. An in vitro bioengineered model of the human arterial neurovascular unit to study neurodegenerative diseases. Mol Neurodegener 2020; 15:70. [PMID: 33213497 PMCID: PMC7678181 DOI: 10.1186/s13024-020-00418-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/03/2020] [Indexed: 01/04/2023] Open
Abstract
INTRODUCTION The neurovascular unit (NVU) - the interaction between the neurons and the cerebrovasculature - is increasingly important to interrogate through human-based experimental models. Although advanced models of cerebral capillaries have been developed in the last decade, there is currently no in vitro 3-dimensional (3D) perfusible model of the human cortical arterial NVU. METHOD We used a tissue-engineering technique to develop a scaffold-directed, perfusible, 3D human NVU that is cultured in native-like flow conditions that mimics the anatomy and physiology of cortical penetrating arteries. RESULTS This system, composed of primary human vascular cells (endothelial cells, smooth muscle cells and astrocytes) and induced pluripotent stem cell (iPSC) derived neurons, demonstrates a physiological multilayer organization of the involved cell types. It reproduces key characteristics of cortical neurons and astrocytes and enables formation of a selective and functional endothelial barrier. We provide proof-of-principle data showing that this in vitro human arterial NVU may be suitable to study neurovascular components of neurodegenerative diseases such as Alzheimer's disease (AD), as endogenously produced phosphorylated tau and beta-amyloid accumulate in the model over time. Finally, neuronal and glial fluid biomarkers relevant to neurodegenerative diseases are measurable in our arterial NVU model. CONCLUSION This model is a suitable research tool to investigate arterial NVU functions in healthy and disease states. Further, the design of the platform allows culture under native-like flow conditions for extended periods of time and yields sufficient tissue and media for downstream immunohistochemistry and biochemistry analyses.
Collapse
Affiliation(s)
- Jerome Robert
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
- Institute of Clinical Chemistry, University hospital Zurich, 8000 Zurich, Wagistrasse 14, CH-8952 Schlieren, Switzerland
| | - Nicholas L. Weilinger
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Li-Ping Cao
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
- Centre for Applied Neurogenetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
| | - Stefano Cataldi
- Centre for Applied Neurogenetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
| | - Emily B. Button
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Sophie Stukas
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Emma M. Martin
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Philip Seibler
- Institute of Neurogenetics, University of Luebeck, 23562 Luebeck, Germany
| | - Megan Gilmour
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Tara M. Caffrey
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Elyn M. Rowe
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Jianjia Fan
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Brian MacVicar
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
| | - Matthew J. Farrer
- Centre for Applied Neurogenetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Laboratory for Neurogenetics & Neuroscience, McKnight and Fixel Institutes, University of Florida, Gainesville, 32610 USA
| | - Cheryl L. Wellington
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, British Columbia V6T 1Z3 Canada
- School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z3 Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia V5Z 1M9 Canada
| |
Collapse
|
50
|
Mai-Morente SP, Marset VM, Blanco F, Isasi EE, Abudara V. A nuclear fluorescent dye identifies pericytes at the neurovascular unit. J Neurochem 2020; 157:1377-1391. [PMID: 32974913 DOI: 10.1111/jnc.15193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/27/2020] [Accepted: 09/14/2020] [Indexed: 11/26/2022]
Abstract
Perivascular pericytes are key regulators of the blood-brain barrier, vascular development, and cerebral blood flow. Deciphering pericyte roles in health and disease requires cellular tracking; yet, pericyte identification remains challenging. A previous study reported that the far-red fluorophore TO-PRO-3 (642/661), usually employed as a nuclear dye in fixed tissue, was selectively captured by live pericytes from the subventricular zone. Herein, we validated TO-PRO-3 as a specific pericyte tracer in the nervous system (NS). Living pericytes from ex vivo murine hippocampus, cortex, spinal cord, and retina robustly incorporated TO-PRO-3. Classical pericyte immunomarkers such as chondroitin sulphate proteoglycan neuron-glial antigen 2 (NG2) and platelet-derived growth factor receptor beta antigen (PDGFrβ) and the new pericyte dye NeuroTrace 500/525 confirmed cellular specificity of dye uptake. The TO-PRO-3 signal enabled quantification of pericytes density and morphometry; likewise, TO-PRO-3 labeling allowed visualization of pericytes associated with other components of the neurovascular unit. A subset of TO-PRO-3 stained cells expressed the contractile protein α-SMA, indicative of their ability to control the capillary diameter. Uptake of TO-PRO-3 was independent of connexin/pannexin channels but was highly sensitive to temperature and showed saturation, suggesting that a yet unidentified protein-mediated active transport sustained dye incorporation. We conclude that TO-PRO-3 labeling provides a reliable and simple tool for the bioimaging of pericytes in the murine NS microvasculature.
Collapse
Affiliation(s)
- Sandra P Mai-Morente
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Virginia M Marset
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Fabiana Blanco
- Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Eugenia E Isasi
- Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Verónica Abudara
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| |
Collapse
|