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Nag TC, Gorla S, Kumari C, Roy TS. Aging of the human choriocapillaris: Evidence that early pericyte damage can trigger endothelial changes. Exp Eye Res 2021; 212:108771. [PMID: 34624336 DOI: 10.1016/j.exer.2021.108771] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/15/2021] [Accepted: 09/17/2021] [Indexed: 01/25/2023]
Abstract
The choriocapillaris (CC), the capillary bed in the choroid, essentially nourishes the photoreceptor cells. Its damage in aging and age-related diseases significantly influences the survival of the photoreceptor cells. Earlier reports implicated endothelial loss in aged and diseased CC; however, age-related pericyte changes and their contribution in CC death remain unknown. We examined human donor eyes (age: 56-94 years; N = 24), and found that CC pericyte damage preceded endothelial changes. With aging (>70 years), the sub-macular choroid accumulated debris in Bruch's membrane (BM). Of the debris content, the long-spaced collagens had a tendency to settle over the capillary basal lamina (BL), and this often resulted in endothelial projection into capillary lumen. Between 75 and 83 years, pericytes contained dark mitochondria, and their processes facing the BM debris showed partial loss of BL and intermediate filaments (IFs), when the endothelium remained unaltered. The endothelial changes appeared beyond 83 years, the abundance of IFs and autophagy reinforced their survival until late aging. TUNEL+ pericytes, and immunoreactivity to carboxymethyl lysine and 4-hydroxy 2-nonenal, but no nitro-tyrosine, was detected in aged CC walls. Iba-1+ dystrophic microglia were present in the vicinity of the CC. Our data indicate that (1) BM debris exerts pressure on the CC, leading to the damage of the capillary BL and pericyte processes (2) loss of IFs results in early pericyte destabilization (3) capillary wall undergoes lipid peroxidative and glycative damage, and (4) pericyte damage leads to late endothelial changes and ultimately CC loss. Future research should explore the normal ways of pericyte maintenance in the aging nervous system.
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Affiliation(s)
- Tapas Chandra Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Shilpa Gorla
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Chiman Kumari
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Tara Sankar Roy
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India
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Dessalles CA, Babataheri A, Barakat AI. Pericyte mechanics and mechanobiology. J Cell Sci 2021; 134:134/6/jcs240226. [PMID: 33753399 DOI: 10.1242/jcs.240226] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pericytes are mural cells of the microvasculature, recognized by their thin processes and protruding cell body. Pericytes wrap around endothelial cells and play a central role in regulating various endothelial functions, including angiogenesis and inflammation. They also serve as a vascular support and regulate blood flow by contraction. Prior reviews have examined pericyte biological functions and biochemical signaling pathways. In this Review, we focus on the role of mechanics and mechanobiology in regulating pericyte function. After an overview of the morphology and structure of pericytes, we describe their interactions with both the basement membrane and endothelial cells. We then turn our attention to biophysical considerations, and describe contractile forces generated by pericytes, mechanical forces exerted on pericytes, and pericyte responses to these forces. Finally, we discuss 2D and 3D engineered in vitro models for studying pericyte mechano-responsiveness and underscore the need for more evolved models that provide improved understanding of pericyte function and dysfunction.
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Affiliation(s)
- Claire A Dessalles
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, 91120, Palaiseau, France
| | - Avin Babataheri
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, 91120, Palaiseau, France
| | - Abdul I Barakat
- LadHyX, CNRS, Ecole polytechnique, Institut polytechnique de Paris, 91120, Palaiseau, France
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Kolinko Y, Marsalova L, Proskauer Pena S, Kralickova M, Mouton PR. Stereological Changes in Microvascular Parameters in Hippocampus of a Transgenic Rat Model of Alzheimer's Disease. J Alzheimers Dis 2021; 84:249-260. [PMID: 34542078 PMCID: PMC8609684 DOI: 10.3233/jad-210738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2021] [Indexed: 11/15/2022]
Abstract
BACKGROUND Microcirculatory factors play an important role in amyloid-β (Aβ)-related neuropathology in Alzheimer's disease (AD). Transgenic (Tg) rat models of mutant Aβ deposition can enhance our understanding of this microvascular pathology. OBJECTIVE Here we report stereology-based quantification and comparisons (between- and within-group) of microvessel length and number and associated parameters in hippocampal subregions in Tg model of AD in Fischer 344 rats and non-Tg littermates. METHODS Systematic-random samples of tissue sections were processed and laminin immunostained to visualize microvessels through the entire hippocampus in Tg and non-Tg rats. A computer-assisted stereology system was used to quantify microvessel parameters including total number, total length, and associated densities in dentate gyrus (DG) and cornu ammonis (CA) subregions. RESULTS Thin hair-like capillaries are common near Aβ plaques in hippocampal subregions of Tg rats. There are a 53% significant increase in average length per capillary across entire hippocampus (p≤0.04) in Tg compared to non-Tg rats; 49% reduction in capillary length in DG (p≤0.02); and, higher microvessel density in principal cell layers (p≤0.03). Furthermore, within-group comparisons confirm Tg but not non-Tg rats have significant increase in number density (p≤0.01) and potential diffusion distance (p≤0.04) of microvessels in principal cell layers of hippocampal subregions. CONCLUSION We show the Tg deposition of human Aβ mutations in rats disrupts the wild-type microanatomy of hippocampal microvessels. Stereology-based microvascular parameters could promote the development of novel strategies for protection and the therapeutic management of AD.
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Affiliation(s)
- Yaroslav Kolinko
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
- Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Lucie Marsalova
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
- Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | | | - Milena Kralickova
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
- Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Peter R. Mouton
- SRC Biosciences, Tampa, FL, USA
- University of South Florida, Tampa, FL, USA
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Ojo J, Eisenbaum M, Shackleton B, Lynch C, Joshi U, Saltiel N, Pearson A, Ringland C, Paris D, Mouzon B, Mullan M, Crawford F, Bachmeier C. Mural cell dysfunction leads to altered cerebrovascular tau uptake following repetitive head trauma. Neurobiol Dis 2020; 150:105237. [PMID: 33383188 PMCID: PMC8170787 DOI: 10.1016/j.nbd.2020.105237] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/07/2020] [Accepted: 12/26/2020] [Indexed: 12/29/2022] Open
Abstract
A pathological characteristic of repetitive traumatic brain injury (TBI) is the deposition of hyperphosphorylated and aggregated tau species in the brain and increased levels of extracellular monomeric tau are believed to play a role in the pathogenesis of neurodegenerative tauopathies. The pathways by which extracellular tau is eliminated from the brain, however, remains elusive. The purpose of this study was to examine tau uptake by cerebrovascular cells and the effect of TBI on these processes. We found monomeric tau interacts with brain vascular mural cells (pericytes and smooth muscle cells) to a greater extent than other cerebrovascular cells, indicating mural cells may contribute to the elimination of extracellular tau, as previously described for other solutes such as beta-amyloid. Consistent with other neurodegenerative disorders, we observed a progressive decline in cerebrovascular mural cell markers up to 12 months post-injury in a mouse model of repetitive mild TBI (r-mTBI) and human TBI brain specimens, when compared to control. These changes appear to reflect mural cell degeneration and not cellular loss as no difference in the mural cell population was observed between r-mTBI and r-sham animals as determined through flow cytometry. Moreover, freshly isolated r-mTBI cerebrovessels showed reduced tau uptake at 6 and 12 months post-injury compared to r-sham animals, which may be the result of diminished cerebrovascular endocytosis, as caveolin-1 levels were significantly decreased in mouse r-mTBI and human TBI cerebrovessels compared to their respective controls. Further emphasizing the interaction between mural cells and tau, similar reductions in mural cell markers, tau uptake, and caveolin-1 were observed in cerebrovessels from transgenic mural cell-depleted animals. In conclusion, our studies indicate repeated injuries to the brain causes chronic mural cell degeneration, reducing the caveolar-mediated uptake of tau by these cells. Alterations in tau uptake by vascular mural cells may contribute to tau deposition in the brain following head trauma and could represent a novel therapeutic target for TBI or other neurodegenerative disorders.
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Affiliation(s)
- Joseph Ojo
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Max Eisenbaum
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Ben Shackleton
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Cillian Lynch
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Utsav Joshi
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | | | - Andrew Pearson
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Charis Ringland
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Daniel Paris
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Benoit Mouzon
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Michael Mullan
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK
| | - Fiona Crawford
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK; James A. Haley Veterans' Hospital, Tampa, FL, USA
| | - Corbin Bachmeier
- The Roskamp Institute, Sarasota, FL, USA; The Open University, Milton Keynes, UK; Bay Pines VA Healthcare System, Bay Pines, FL, USA.
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Giorgi FS, Galgani A, Puglisi-Allegra S, Limanaqi F, Busceti CL, Fornai F. Locus Coeruleus and neurovascular unit: From its role in physiology to its potential role in Alzheimer's disease pathogenesis. J Neurosci Res 2020; 98:2406-2434. [PMID: 32875628 DOI: 10.1002/jnr.24718] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/26/2020] [Accepted: 08/08/2020] [Indexed: 12/15/2022]
Abstract
Locus coeruleus (LC) is the main noradrenergic (NA) nucleus of the central nervous system. LC degenerates early during Alzheimer's disease (AD) and NA loss might concur to AD pathogenesis. Aside from neurons, LC terminals provide dense innervation of brain intraparenchymal arterioles/capillaries, and NA modulates astrocyte functions. The term neurovascular unit (NVU) defines the strict anatomical/functional interaction occurring between neurons, glial cells, and brain vessels. NVU plays a fundamental role in coupling the energy demand of activated brain regions with regional cerebral blood flow, it includes the blood-brain barrier (BBB), plays an active role in neuroinflammation, and participates also to the glymphatic system. NVU alteration is involved in AD pathophysiology through several mechanisms, mainly related to a relative oligoemia in activated brain regions and impairment of structural and functional BBB integrity, which contributes also to the intracerebral accumulation of insoluble amyloid. We review the existing data on the morphological features of LC-NA innervation of the NVU, as well as its contribution to neurovascular coupling and BBB proper functioning. After introducing the main experimental data linking LC with AD, which have repeatedly shown a key role of neuroinflammation and increased amyloid plaque formation, we discuss the potential mechanisms by which the loss of NVU modulation by LC might contribute to AD pathogenesis. Surprisingly, thus far not so many studies have tested directly these mechanisms in models of AD in which LC has been lesioned experimentally. Clarifying the interaction of LC with NVU in AD pathogenesis may disclose potential therapeutic targets for AD.
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Affiliation(s)
- Filippo Sean Giorgi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.,Neurology Unit, Pisa University Hospital, Pisa, Italy
| | | | | | - Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.,I.R.C.C.S. I.N.M. Neuromed, Pozzilli, Italy
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Qin W, Li J, Zhu R, Gao S, Fan J, Xia M, Zhao RC, Zhang J. Melatonin protects blood-brain barrier integrity and permeability by inhibiting matrix metalloproteinase-9 via the NOTCH3/NF-κB pathway. Aging (Albany NY) 2019; 11:11391-11415. [PMID: 31811815 PMCID: PMC6932927 DOI: 10.18632/aging.102537] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 11/19/2019] [Indexed: 05/13/2023]
Abstract
The pathophysiological mechanism of white matter hyperintensities of cerebral small vessel disease (CSVD) includes an impaired blood-brain barrier (BBB) with increased permeability. Neuroinflammation likely contributes to the disruption of the BBB in CSVD. Therefore, understanding the molecular mechanism of how neuroinflammation causes BBB damage is essential to preventing BBB disruption in CSVD. Matrix metalloproteinase 9 (MMP-9) contributes to BBB damage in neuroinflammatory diseases. In this study, we observed that interleukin-1β (IL-1β)-induced MMP-9 secretion in pericytes increased BBB permeability to sodium fluorescein (Na-F) by damaging the disruption of VE-cadherin, occludin, claudin-5, and zonula occludin-1 (ZO-1). Melatonin reduced BBB permeability to Na-F and inhibited the disruption of the adherens and tight junction proteins. Melatonin also downregulated MMP-9 and upregulated tissue inhibitor of metalloproteinases 1 (TIMP-1) gene expression, which decreased the MMP-9/TIMP-1 ratio. In addition, nuclear translocation of NF-κB/p65 induced by IL-1β in pericytes upregulated MMP-9 expression, which was inhibited by the NF-κB inhibitor PDTC. However, the NOTCH3 inhibitor DAPT significantly inhibited NF-κB/p65 translocation to the nucleus, while melatonin in combination with DAPT significantly prevented NF-κB/p65 translocation than DAPT alone. Our results suggest that melatonin reduced MMP-9-induced permeability of the BBB. Melatonin reduced MMP-9 expression and activity, which was induced by IL-1β through the regulation of the NOTCH3/NF-κB signaling pathway in pericytes, suggesting that pericytes regulate BBB integrity and function.
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Affiliation(s)
- Weiwei Qin
- Department of Neurology, State Key Clinical Specialty of the Ministry of Health for Neurology, Henan Provincial People’s Hospital, School of Clinical Medicine, Henan University, Zhengzhou, Henan, China
| | - Jing Li
- Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Beijing Key Laboratory (No. BZO381), Beijing 100005, China
| | - Rongjia Zhu
- Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Beijing Key Laboratory (No. BZO381), Beijing 100005, China
| | - Suhua Gao
- Department of Scientific Research and Discipline Construction, Henan Provincial People’s Hospital, Zhengzhou, Henan, China
| | - Junfen Fan
- Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Beijing Key Laboratory (No. BZO381), Beijing 100005, China
| | - Mingrong Xia
- Department of Neurology, State Key Clinical Specialty of the Ministry of Health for Neurology, Henan Provincial People’s Hospital, School of Clinical Medicine, Henan University, Zhengzhou, Henan, China
| | - Robert Chunhua Zhao
- Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Beijing Key Laboratory (No. BZO381), Beijing 100005, China
| | - Jiewen Zhang
- Department of Neurology, State Key Clinical Specialty of the Ministry of Health for Neurology, Henan Provincial People’s Hospital, School of Clinical Medicine, Henan University, Zhengzhou, Henan, China
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Ago T. [Why are pericytes important for brain functions?]. Rinsho Shinkeigaku 2019; 59:707-715. [PMID: 31656270 DOI: 10.5692/clinicalneurol.cn-001357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Pericytes are mural cells embedded in the basal membrane surrounding endothelial cells in capillary and small vessels (from precapillary arterioles to postcapillary venules). They exist with a high coverage ratio to endothelial cells in the brain and play crucial roles in the formation and maintenance of the blood-brain barrier and the control of blood flow through a close interaction with endothelial cells. Thus, intactness of pericyte is absolutely needed for neuronal/brain functions. Ageing, life-style diseases, hypoperfusion/ischemia, drugs, and genetic factors can primarily cause pericyte dysfunctions, thereby leading to the development or progression of various brain disorders, including cerebrovascular diseases. Because pericytes also play an important role in tissue repair after brain injuries, they have received much attention as a therapeutic target even from the standpoint of functional recovery.
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Affiliation(s)
- Tetsuro Ago
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University
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