scholarly journals Organizational hierarchy and structural diversity of microvascular pericytes in adult mouse cortex

2017 ◽  
Vol 39 (3) ◽  
pp. 411-425 ◽  
Author(s):  
Roger I Grant ◽  
David A Hartmann ◽  
Robert G Underly ◽  
Andrée-Anne Berthiaume ◽  
Narayan R Bhat ◽  
...  

Smooth muscle cells and pericytes, together called mural cells, coordinate many distinct vascular functions. Canonically, smooth muscle cells are ring-shaped and cover arterioles with circumferential processes, whereas pericytes extend thin processes that run longitudinally along capillaries. In between these canonical mural cell types are cells with features of both smooth muscle cells and pericytes. Recent studies suggest that these transitional cells are critical for controlling blood flow to the capillary bed during health and disease, but there remains confusion on how to identify them and where they are located in the brain microvasculature. To address this issue, we measured the morphology, vascular territory, and α-smooth muscle actin content of structurally diverse mural cells in adult mouse cortex. We first imaged intact 3D vascular networks to establish the locations of major gradations in mural cell appearance as arterioles branched into capillaries. We then imaged individual mural cells occupying the regions within these gradations. This revealed two transitional cells that were often similar in appearance, but with sharply contrasting levels of α-smooth muscle actin. Our findings highlight the diversity of mural cell morphologies in brain microvasculature, and provide guidance for identification and categorization of mural cell types.

2017 ◽  
Author(s):  
Roger I. Grant ◽  
David A. Hartmann ◽  
Robert G. Underly ◽  
Andrée-Anne Berthiaume ◽  
Narayan R. Bhat ◽  
...  

ABSTRACTSmooth muscle cells and pericytes, together called mural cells, coordinate many distinct vascular functions. Smooth muscle cells are ring-shaped and cover arterioles with circumferential processes, whereas pericytes extend thin processes that run longitudinally along capillaries. In between these canonical mural cell types are cells with mixed phenotype of both smooth muscle cells and pericytes. Recent studies suggest that these transitional cells are critical for controlling blood flow to the capillary bed during health and disease, but there remains confusion on how to identify them and where they are located in the brain microvasculature. To address this issue, we measured the morphology, vascular territory, and α-smooth muscle actin content of structurally diverse mural cells in adult mouse cortex. We first imaged intact 3-D vascular networks to establish the locations of major gradations in mural cell appearance as arterioles branched into capillaries. We then imaged individual mural cells occupying the regions within these gradations. This revealed two transitional cells that were often similar in appearance, but with sharply contrasting levels of α-smooth muscle actin. Our findings highlight the diversity of mural cell morphologies in brain microvasculature, and provide guidance for identification and categorization of mural cell types.


PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e90590 ◽  
Author(s):  
Thomas R. Whitesell ◽  
Regan M. Kennedy ◽  
Alyson D. Carter ◽  
Evvi-Lynn Rollins ◽  
Sonja Georgijevic ◽  
...  

1989 ◽  
Vol 37 (3) ◽  
pp. 315-321 ◽  
Author(s):  
O Skalli ◽  
M F Pelte ◽  
M C Peclet ◽  
G Gabbiani ◽  
P Gugliotta ◽  
...  

alpha-Smooth muscle (alpha-sm) actin, an isoform typical of smooth muscle cells (SMC) and present in high amounts in vascular SMC, was demonstrated in the cytoplasm of pericytes of various rat and human organs by means of immunocytochemistry at the electron microscopic level. In SMC and pericytes, alpha-sm actin was localized in microfilament bundles, strengthening the assumption that it is the functional isoform in these cell types and supporting the assumption that pericytes exert contractile functions.


2020 ◽  
Vol 21 (6) ◽  
pp. 2158 ◽  
Author(s):  
Soo Jin Kim ◽  
Sang A. Kim ◽  
Yeong A. Choi ◽  
Do Young Park ◽  
Junyeop Lee

Structural alterations of pericytes in microvessels are important features of diabetic retinopathy. Although capillary pericytes had been known not to have α-smooth muscle actin (αSMA), a recent study revealed that a specific fixation method enabled the visualization of αSMA along retinal capillaries. In this study, we applied snap-fixation in wild type and streptozotocin-induced diabetic mice to evaluate the differences in vascular smooth muscle cells of the retina and the choroid. Mice eyeballs were fixed in ice-cold methanol to prevent the depolymerization of filamentous actin. Snap-fixated retina showed αSMA expression in higher-order branches along the capillaries as well as the arterioles and venules, which were not detected by paraformaldehyde fixation. In contrast, most choriocapillaris, except those close to the arterioles, were not covered with αSMA-positive perivascular mural cells. Large choroidal vessels were covered with more αSMA-positive cells in the snap-fixated eyes. Diabetes induced less coverage of αSMA-positive perivascular mural cells overall, but they reached higher-order branches of the retinal capillaries, which was prominent in the aged mice. More αSMA-positive pericytes were observed in the choroid of diabetic mice, but the αSMA-positive expression reduced with aging. This study suggests the potential role of smooth muscle cells in the pathogenesis of age-related diabetic retinopathy and choroidopathy.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Martin Liu ◽  
Angelos Karagiannis ◽  
Matthew Sis ◽  
Srivatsan Kidambi ◽  
Yiannis Chatzizisis

Objectives: To develop and validate a 3D in-vitro model of atherosclerosis that enables direct interaction between various cell types and/or extracellular matrix. Methods and Results: Type I collagen (0.75 mg/mL) was mixed with human artery smooth muscle cells (SMCs; 6x10 5 cells/mL), medium, and water. Human coronary artery endothelial cells (HCAECs; 10 5 /cm 2 ) were plated on top of the collagen gels and activated with oxidized low density lipoprotein cholesterol (LDL-C). Monocytes (THP-1 cells; 10 5 /cm 2 ) were then added on top of the HCAECs. Immunofluorescence showed the expression of VE-cadherin by HCAECs (A, B) and α-smooth muscle actin by SMCs (A). Green-labelled LDL-C particles were accumulated in the subendothelial space, as well as in the cytoplasm of HCAECs and SMCs (C). Activated monocytes were attached to HCAECs and found in the subendothelial area (G-I). Both HCAECs and SMCs released IL-1β, IL-6, IL-8, PDGF-BB, TGF-ß1, and VEGF. Scanning and transmission electron microscopy showed the HCAECs monolayer forming gap junctions and the SMCs (D-F) and transmigrating monocytes within the collagen matrix (G-I). Conclusions: In this work, we presented a novel, easily reproducible and functional in-vitro experimental model of atherosclerosis that has the potential to enable in-vitro sophisticated molecular and drug development studies.


1996 ◽  
Vol 270 (2) ◽  
pp. C488-C499 ◽  
Author(s):  
R. M. Lynch ◽  
W. Carrington ◽  
K. E. Fogarty ◽  
F. S. Fay

Hexokinase isoform I binds to mitochondria of many cell types. It has been hypothesized that this association is regulated by changes in the concentrations of specific cellular metabolites. To study the distribution of hexokinase in living cells, fluorophore-labeled functional hexokinase I was prepared. After microinjection into A7r5 smooth muscle cells, hexokinase localized to distinct structures identified as mitochondria. The endogenous hexokinase demonstrated a similar distribution with the use of immunocytochemistry. 2-Deoxyglucose elicited an increase in glucose 6-phosphate (G-6-P) and a decrease in ATP levels and diminished hexokinase binding to mitochondria in single cells. 3-O-methylglucose elicited slowly developing decreases in all three parameters. In contrast, cyanide elicited a rapid decrease in both ATP and hexokinase binding. Analyses of changes in metabolite levels and hexokinase binding indicate a positive correlation between binding and cell energy state as monitored by ATP. On the other hand, only in the presence of 2-deoxyglucose was the predicted inverse correlation between binding and G-6-P observed. Unlike the relatively large changes in distribution observed with the fluorescent-injected hexokinase, cyanide caused only a small decrease in the localization of endogenous hexokinase with mitochondria. These findings suggest that changes in the concentrations of specific metabolites can alter the binding of hexokinase I to specific sites on mitochondria. Moreover, the apparent difference in sensitivity of injected and endogenous hexokinase to changes in metabolites may reflect the presence of at least two classes of binding mechanisms for hexokinase, with differential sensitivity to metabolites.


2010 ◽  
Vol 67 (12) ◽  
pp. 977-982 ◽  
Author(s):  
Aleksandra Mladenovic-Mihailovic ◽  
Zorica Mladenovic-Bogdanovic ◽  
Predrag Mitrovic ◽  
Irena Tanaskovic ◽  
Slavica Usaj-Knezevic ◽  
...  

Background/Aim. Myomas of the uterus, the most common benign tumors, have been studied for decades from the aspects of different basic and clinical disciplines. Despite this fact, their pathogenesis is still poorly understood. The aim of this study was to determine immunocytochemical characteristics of smooth muscle cells and connective tissue components of submucosal myomas of the uterus. Method. During the course of this study, 25 samples of submucosal myomas of the uterus were analyzed, all of them obtained during the surgery, after abdominal histerctomy by Aldridge. The samples were fixed in 4% formalin and embedded in paraffin. Sections of 5 ?m thickness were stained immunocytochemically using the DAKO LSAB+/HRP technique to identify ?- smooth muscle actin (?-SMA), vimentin, desmin, CD34, CD45, CD68 and PCNA (DAKO specification). Results. Our results suggest that submucosal myomas of the uterus are build-up of smooth muscle cells which are immunoreactive to ?-SMA and desmin, but also to a certain number of smooth muscle cells which are immunoreactive to ?-SMA and vimentin. Some of vimentin-immunoreactive cells also show an immunoreactivity of PCNA. In the build-up of connective stroma CD34-immunoreactive fibroblasts and neovascular formations are also present. By examining the distribution of CD45 antigen, at all the analyzed samples we observed a weak reaction. Conclusion. Submucosal myomas of the uterus are made-up of smooth muscle cells of the highly differentiated contractile phenotype (?-SMA- and desminimmunoreactivity), as well as smooth muscle cell of the synthetic phenotype which proliferate (?-SMA-, vimentin- and PCNA-immunoreactivity). In submucosal myoma of the uterus there is a significant presence of connective tissue as a result of synthetic activity of fibroblasts, which clearly differ in their immunocytochemical characteristics from smooth muscle cells of the synthetic phenotype.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Silvia Castiglioni ◽  
Alessio Vettore ◽  
Lorenzo Arnaboldi ◽  
Laura Calabresi ◽  
Alberto Corsini ◽  
...  

Cells of the artery wall may accumulate free cholesterol and cholesteryl esters becoming foam cells. Up to 50% of foam cells in human lesions originates from smooth muscle cells (SMCs). Arterial SMCs express the ATP binding cassette (ABC) transporter ABCA1 and, upon cholesterol loading, express macrophage markers and a phagocytic activity. To characterize the role of ABCA1 and HDL3 in this transdifferentiation process, we evaluated the phenotypic changes in SMCs isolated from wild type (WT) and ABCA1 knock out (KO) mice and how HDL3 affects these changes. Cholesterol loading causes the downregulation of the expression of SMC markers including ACTA2, alpha-tropomyosin and myosin heavy chain and increases the expression of macrophage-related genes such as CD68, Mac-2, SRB1, MMPs, ABCG1 and ABCA1. HDL3 treatment in WT cells is able to normalize the expression of ACTA2, while the expression of macrophage-related genes is reduced. On the contrary, the preventive effect of HDL3 is completely lost in ABCA1 KO cells. Interestingly, the presence of HDL3 does not differently affect neutral lipid accumulation in WT or ABCA1 KO cells but stimulates phospholipids removal only in WT cells. ApoAI addition does not reverse the phenotypic changes induced by cholesterol not only in KO but also in WT cells. Moreover, cholesterol loading reduces the expression of myocardin, the master SMC specific-transcriptional coactivator involved in SMC differentiation, by up to 55% (p<0.01 vs respective control) in both cell types. HDL3 normalizes myocardin levels in WT cells while it does not have any effect in ABCA1 KO cells. Similar results are obtained evaluating the levels of miR-143/145, which positively regulate myocardin. The basal expression level of KLF4, a myocardin repressor, is almost double in ABCA1 KO cells compared to WT. After cholesterol loading, KLF4 is slightly reduced in WT cells, while its expression is halved in ABCA1 KO cells. HDL3 restores KLF4 to basal levels in KO cells, but it further reduces them in WT cells. These results indicate that HDL3, modulating the miR143/145-myocardin axis in SMC, prevents the cholesterol-induced gene expression modification regardless of its cholesterol unloading capacity and the presence of ABCA1 is required.


Author(s):  
T.C. Steven Keller ◽  
Christophe Lechauve ◽  
Alexander S Keller ◽  
Steven Brooks ◽  
Mitchell J Weiss ◽  
...  

Globin proteins exist in every cell type of the vasculature, from erythrocytes to endothelial cells, vascular smooth muscle cells, and peripheral nerve cells. Many globin subtypes are also expressed in muscle tissues (including cardiac and skeletal muscle), in other organ-specific cell types, and in cells of the central nervous system. The ability of each of these globins to interact with molecular oxygen (O2) and nitric oxide (NO) is preserved across these contexts. Endothelial α-globin is an example of extra-erythrocytic globin expression. Other globins, including myoglobin, cytoglobin, and neuroglobin are observed in other vascular tissues. Myoglobin is observed primarily in skeletal muscle and smooth muscle cells surrounding the aorta or other large arteries. Cytoglobin is found in vascular smooth muscle but can also be expressed in non-vascular cell types, especially in oxidative stress conditions after ischemic insult. Neuroglobin was first observed in neuronal cells, and its expression appears to be restricted mainly to the central and peripheral nervous systems. Brain and central nervous system neurons expressing neuroglobin are positioned close to many arteries within the brain parenchyma and can control smooth muscle contraction and, thus, tissue perfusion and vascular reactivity. Overall, reactions between NO and globin heme-iron contribute to vascular homeostasis by regulating vasodilatory NO signals and scaveging reactive species in cells of the mammalian vascular system. Here, we discuss how globin proteins affect vascular physiology with a focus on NO biology, and offer perspectives for future study of these functions.


2003 ◽  
Vol 285 (1) ◽  
pp. L55-L62 ◽  
Author(s):  
Katharina von der Hardt ◽  
Michael Andreas Kandler ◽  
Ludger Fink ◽  
Ellen Schoof ◽  
Jörg Dötsch ◽  
...  

The aim of this study was to identify cell types involved in the anti-inflammatory effect of ventilation with perfluorocarbon in vivo. Fifteen anesthetized, surfactant-depleted piglets received either aerosolized perfluorocarbon (Aerosol-PFC), partial liquid ventilation (rLV) at functional residual capacity (FRC) volume (FRC-PLV), or intermittent mandatory ventilation (control). After laser-assisted microdissection of different lung cell types, mRNA expression of IL-8 and ICAM-1 was determined using TaqMan real-time PCR normalized to hypoxanthine phosphoribosyltransferase (HPRT). IL-8 mRNA expression (means ± SE; control vs. Aerosol-PFC) was 356 ± 142 copies IL-8 mRNA/copy HPRT mRNA vs. 3.5 ± 1.8 in alveolar macrophages ( P <0.01); 208 ± 108 vs. 2.7 ± 0.8 in bronchiolar epithelial cells ( P <0.05); 26 ± 11 vs. 0.7 ± 0.2 in alveolar septum cells ( P <0.01); 2.8 ± 1.0 vs. 0.8 ± 0.4 in bronchiolar smooth muscle cells ( P <0.05); and 1.1 ± 0.4 vs. 0.2 ± 0.05 in vascular smooth muscle cells ( P <0.05). With FRC-PLV, IL-8/HPRT mRNA expression was significantly lower in macrophages, bronchiolar epithelial, and vascular smooth muscle cells. ICAM-1 mRNA expression in vascular endothelial cells remained unchanged. Predominantly, alveolar macrophages and bronchiolar epithelial cells were involved in the inflammatory pulmonary process. The anti-inflammatory effect of Aerosol-PFC was most pronounced.


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