skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: The pericyte microenvironment during vascular development
Abstract Vascular pericytes provide critical contributions to the formation and integrity of the blood vessel wall within the microcirculation. Pericytes maintain vascular stability and homeostasis by promoting endothelial cell junctions and depositing extracellular matrix (ECM) components within the vascular basement membrane, among other vital functions. As their importance in sustaining microvessel health within various tissues and organs continues to emerge, so does their role in a number of pathological conditions including cancer, diabetic retinopathy, and neurological disorders. Here, we review vascular pericyte contributions to the development and remodeling of the microcirculation, with a focus on the local microenvironment during these processes. We discuss observations of their earliest involvement in vascular development and essential cues for their recruitment to the remodeling endothelium. Pericyte involvement in the angiogenic sprouting context is also considered with specific attention to crosstalk with endothelial cells such as through signaling regulation and ECM deposition. We also address specific aspects of the collective cell migration and dynamic interactions between pericytes and endothelial cells during angiogenic sprouting. Lastly, we discuss pericyte contributions to mechanisms underlying the transition from active vessel remodeling to the maturation and quiescence phase of vascular development.  more » « less
Award ID(s):
1752339
PAR ID:
10459322
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Microcirculation
Volume:
26
Issue:
8
ISSN:
1073-9688
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; (, Integrative Biology)
    null (Ed.)
    Abstract Pericytes are critical for microvascular stability and maintenance, among other important physiological functions, yet their involvement in vessel formation processes remains poorly understood. To gain insight into pericyte behaviors during vascular remodeling, we developed two complementary tissue explant models utilizing ‘double reporter’ animals with fluorescently-labeled pericytes and endothelial cells (via Ng2:DsRed and Flk-1:eGFP genes, respectively). Time-lapse confocal imaging of active vessel remodeling within adult connective tissues and embryonic skin revealed a subset of pericytes detaching and migrating away from the vessel wall. Vessel-associated pericytes displayed rapid filopodial sampling near sprouting endothelial cells that emerged from parent vessels to form nascent branches. Pericytes near angiogenic sprouts were also more migratory, initiating persistent and directional movement along newly forming vessels. Pericyte cell divisions coincided more frequently with elongating endothelial sprouts, rather than sprout initiation sites, an observation confirmed with in vivo data from the developing mouse brain. Taken together, these data suggest that (i) pericyte detachment from the vessel wall may represent an important physiological process to enhance endothelial cell plasticity during vascular remodeling, and (ii) pericyte migration and proliferation are highly synchronized with endothelial cell behaviors during the coordinated expansion of a vascular network. 
    more » « less
  2. (, Vascularized Cortical Organoid Microphysiological System To Model Alzheimer’s Disease)
    Human induced pluripotent stem cell (hiPSC)-derived brain organoids can recapitulate the complex cytoarchitecture of the brain as well as the genetic and epigenetic footprint of human brain development. Although the brain organoids are able to mimic the structures and functions of brain in vitro, the 3D models have difficulty in integrating a complex vascular network that can provide the interaction with organoids. Here we report on a microfluidicbased three-dimensional, vascularized cortical organoid tissue construct consisting of 1) a perfused micro-vessel against an extracellular matrix (ECM), dynamic flow and membrane-free culture of the endothelial layer, 2) a sprouted vascular network using a combination of angiogenic factors, and 3) a vascularized hiPSCderived cortical organoid. We report on an optimization of density/stiffness of ECM to induce angiogenic sprouting and effect of angiogenic factors to trigger robust, rapid, and directional angiogenesis for concentration-driven and repetitive sprout formation. Vascularized network in the microfluidic device was further characterized in terms of morphology, directional alignment under perfusion, lumen formation, and permeability. HiPSCderived cortical organoid was generated, placed, and integrated into a vascularized network in the vascularized microfluidic device. We investigate how vascularized micro-vessels interact with cortical organoid. This paper further demonstrates the potential utility of a membrane-free vascularized cortical organoid in perfusion used to model Alzheimer’s disease and for toxicity screening of nerve agents. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; ; et al (, Biomolecules)
    The platelet-derived growth factor-BB (PDGF-BB) pathway provides critical regulation of cerebrovascular pericytes, orchestrating their investment and retention within the brain microcirculation. Dysregulated PDGF Receptor-beta (PDGFRβ) signaling can lead to pericyte defects that compromise blood-brain barrier (BBB) integrity and cerebral perfusion, impairing neuronal activity and viability, which fuels cognitive and memory deficits. Receptor tyrosine kinases such as PDGF-BB and vascular endothelial growth factor-A (VEGF-A) are often modulated by soluble isoforms of cognate receptors that establish signaling activity within a physiological range. Soluble PDGFRβ (sPDGFRβ) isoforms have been reported to form by enzymatic cleavage from cerebrovascular mural cells, and pericytes in particular, largely under pathological conditions. However, pre-mRNA alternative splicing has not been widely explored as a possible mechanism for generating sPDGFRβ variants, and specifically during tissue homeostasis. Here, we found sPDGFRβ protein in the murine brain and other tissues under normal, physiological conditions. Utilizing brain samples for follow-on analysis, we identified mRNA sequences corresponding to sPDGFRβ isoforms, which facilitated construction of predicted protein structures and related amino acid sequences. Human cell lines yielded comparable sequences and protein model predictions. Retention of ligand binding capacity was confirmed for sPDGFRβ by co-immunoprecipitation. Visualizing fluorescently labeled sPDGFRβ transcripts revealed a spatial distribution corresponding to murine brain pericytes alongside cerebrovascular endothelium. Soluble PDGFRβ protein was detected throughout the brain parenchyma in distinct regions, such as along the lateral ventricles, with signals also found more broadly adjacent to cerebral microvessels consistent with pericyte labeling. To better understand how sPDGFRβ variants might be regulated, we found elevated transcript and protein levels in the murine brain with age, and acute hypoxia increased sPDGFRβ variant transcripts in a cell-based model of intact vessels. Our findings indicate that soluble isoforms of PDGFRβ likely arise from pre-mRNA alternative splicing, in addition to enzymatic cleavage mechanisms, and these variants exist under normal physiological conditions. Follow-on studies will be needed to establish potential roles for sPDGFRβ in regulating PDGF-BB signaling to maintain pericyte quiescence, BBB integrity, and cerebral perfusion—critical processes underlying neuronal health and function, and in turn, memory and cognition. 
    more » « less
  4. ; ; ; ; (, Advanced Healthcare Materials)
    Abstract Angiogenesis is associated with increased vessel sprouting and permeability. Important mediators of these angiogenic responses include local environment of signaling molecules and supporting extracellular matrix (ECM). However, dissecting the interplay of these instructive signals in vivo with multiple cells and extracellular molecules remains a central challenge. Here, microfluidic biomimicry is integrated with 3D ECM hydrogels that are well‐characterized for molecular‐binding and mechanical properties to reconstitute vessel‐like analogues in vitro. This study focuses on three distinct isoforms of the pro‐metastatic chemokine CXCL12. In collagen‐only hydrogel, CXCL12‐α is the most potent isoform in promoting sprouting and permeability, followed by CXCL12‐β and CXCL12‐γ. Strikingly, addition of hyaluronan (HA), a large and negatively charged glycosaminoglycan, with collagen matrices selectively increases vessel sprouting and permeability conferred by CXCL12‐γ. This outcome is supported by the measured binding affinities to collagen/HA ECM, suggesting that negatively charged HA increases the binding of CXCL12‐γ to augment its angiogenic potency. Moreover, it is shown that addition of HA to collagen matrices on its own decreases vessel sprouting and permeability, and these responses are nullified by blocking the HA receptor CD44. Collectively, these results demonstrate that differences in binding to extracellular HA help underlie CXCL12 isoform‐specific responses toward directing angiogenesis. 
    more » « less
  5. ; ; ; ; ; (, Frontiers in Cardiovascular Medicine)
    The extracellular matrix (ECM) represents a complex and dynamic framework for cells, characterized by tissue-specific biophysical, mechanical, and biochemical properties. ECM components in vascular tissues provide structural support to vascular cells and modulate their function through interaction with specific cell-surface receptors. ECM–cell interactions, together with neurotransmitters, cytokines, hormones and mechanical forces imposed by blood flow, modulate the structural organization of the vascular wall. Changes in the ECM microenvironment, as in post-injury degradation or remodeling, lead to both altered tissue function and exacerbation of vascular pathologies. Regeneration and repair of the ECM are thus critical toward reinstating vascular homeostasis. The self-renewal and transdifferentiating potential of stem cells (SCs) into other cell lineages represents a potentially useful approach in regenerative medicine, and SC-based approaches hold great promise in the development of novel therapeutics toward ECM repair. Certain adult SCs, including mesenchymal stem cells (MSCs), possess a broader plasticity and differentiation potential, and thus represent a viable option for SC-based therapeutics. However, there are significant challenges to SC therapies including, but not limited to cell processing and scaleup, quality control, phenotypic integrity in a disease milieu in vivo , and inefficient delivery to the site of tissue injury. SC-derived or -inspired strategies as a putative surrogate for conventional cell therapy are thus gaining momentum. In this article, we review current knowledge on the patho-mechanistic roles of ECM components in common vascular disorders and the prospects of developing adult SC based/inspired therapies to modulate the vascular tissue environment and reinstate vessel homeostasis in these disorders. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email