Isolation and Profiling of Human Primary Mesenteric Arterial Endothelial Cells at the Transcriptome Level

Summary

The protocol describes the isolation, culture, and profiling of endothelial cells from human mesenteric artery. Additionally, a method is provided to prepare human artery for spatial transcriptomics. Proteomics, transcriptomics, and functional assays can be performed on isolated cells. This protocol can be repurposed for any medium- or large-size artery.

Abstract

Endothelial cells (ECs) are crucial for vascular and whole-body function through their dynamic response to environmental cues. Elucidating the transcriptome and epigenome of ECs is paramount to understanding their roles in development, health, and disease, but is limited in the availability of isolated primary cells. Recent technologies have enabled the high-throughput profiling of EC transcriptome and epigenome, leading to the identification of previously unknown EC cell subpopulations and developmental trajectories. While EC cultures are a useful tool in the exploration of EC function and dysfunction, the culture conditions and multiple passages can introduce external variables that alter the properties of native EC, including morphology, epigenetic state, and gene expression program. To overcome this limitation, the present paper demonstrates a method of isolating human primary ECs from donor mesenteric arteries aiming to capture their native state. ECs in the intimal layer are dissociated mechanically and biochemically with the use of particular enzymes. The resultant cells can be directly used for bulk RNA or single-cell RNA-sequencing or plated for culture. In addition, a workflow is described for the preparation of human arterial tissue for spatial transcriptomics, specifically for a commercially available platform, although this method is also suitable for other spatial transcriptome profiling techniques. This methodology can be applied to different vessels collected from a variety of donors in health or disease states to gain insights into EC transcriptional and epigenetic regulation, a pivotal aspect of endothelial cell biology.

Introduction

Lining the lumen of blood vessels, endothelial cells (ECs) are crucial regulators of vascular tone and tissue perfusion. ECs are remarkable in their ability to react to the extracellular environment and adapt to changes in the dynamics and composition of blood flow. These dynamic responses are mediated through a network of intracellular signaling events, including transcriptional and post-transcriptional modulations with spatio-temporal resolution. The dysregulation of these responses is implicated in many pathologies, including but not limited to cardiovascular disease, diabetes, and cancer^1,2.

Protocol

Human tissue studies were conducted on deidentified specimens obtained from the Southern California Islet Cell Resource Center at City of Hope. The research consents for the use of postmortem human tissues were obtained from the donors' next of kin, and ethical approval for this study was granted by the Institutional Review Board of City of Hope (IRB No. 01046).

1. Physical dissociation (estimated time: 1-2 h)

1. Place a fresh artery on a 10 cm dish and wash with .......

Discussion

The presented workflow details a set of techniques to profile ECs from a single piece of human artery with single-cell and spatial resolution. There are several critical steps and limiting factors in the protocol. One key to transcriptome profiling is the freshness of the tissue and RNA integrity. It is important to maintain tissues on ice as much as possible prior to processing to minimize RNA degradation. Typically, the post-mortem tissues are processed between 8-14 h after the time of death. However, beginning the iso.......

Materials

Name	Company	Catalog Number	Comments
1.5 mL micro-centrifuge tube	USA Scientific	1615-5500
10 cm dish	Genesee Scientific	25-202
23G needles	BD	305145
2-methylbutane	Thermo Fisher	AC327270010
40 µm strainer	Fisher	14100150
4200 TapeStation System	Agilent Technologies	G2991BA
5 mL tube	Thermo Fisher	14282300
6-well plate	Greiner Bio-One	07-000-208
Attachment factor	Cell Applications	123-500	Attachment reagent in the protocol
Black wax			Any commercial black wax can be used
Bovine serum albumin heat shock treated	Fisher	BP1600-100
CaCl2	Fisher	BP510
Centrifuge	Eppendorf
Chloroform	Fisher	C607
Collagenase D	Roche	11088866001
Cryostat	Leica
Cryostat brushes
D-Glucose	Fisher	D16-1
Dimethyl sulfoxide	Fisher	MT25950CQC
Dispase II	Roche	4942078001	Bacteria-derived protease in the protocol
Disposable Safety Scalpels	Myco Instrumentation	6008TR-10
D-PBS	Thermo Fisher	14080055
Ethanol	Fisher	BP2818-4
Fetal bovine serum	Fisher	10437028
Hemocytometer	Fisher	267110
HEPES	Sigma Aldrich	H3375-100g
High sensitivity D1000 sample buffer	Agilent Technologies	5067-5603
High sensitivity D1000 screen tape	Agilent Technologies	5067-5584
Incubator			Kept at 37 °C 5% CO2
Isopropanol	Fisher	BP26324
KCl	Fisher	P217-3
Liquid nitrogen
Medium 199	Sigma Aldrich	M2520-10X
Metal cannister
Microscope	Leica		To assess cell morphology
Microvascular endothelial culture medium	Cell Applications	111-500
NaCl	Fisher	S271-1
New Brunswick Innova 44/44R Orbital shaker	Eppendorf
Optimal Cutting Temperature compound	Fisher	4585
Plastic cryomolds	Fisher	22363553
RNA screen tape	Agilent Technologies	5067-5576
RNA screen Tape sample buffer	Agilent Technologies	5067-5577
RNase ZAP	Thermo Fisher	AM9780
RNase-free water	Takara	RR036B	RNase-free water (2) in kit
Sterile 12" long forceps	F.S.T	91100-16
Sterile fine forceps	F.S.T	11050-10
Sterile fine scissors	F.S.T	14061-11
Superfrost PLUS Gold Slides	Fisher	1518848
TRIzol reagent	Fisher	15596018
Trypan Blue	Corning	MT25900CI
TrypLE Express Enzyme (1X) phenol red	Thermo Fisher	12605010	Cell-dissociation enzyme in the protocol
Visium Accessory Kit	10X Genomics	PN-1000215
Visium Gateway Package, 2rxns	10X Genomics	PN-1000316
Visium Spatial Gene Expression Slide & Reagent Kit, 4 rxns	10X Genomics	PN-1000184