Single-Cell Sorting of Immunophenotyped Mesenchymal Stem Cells from Human Exfoliated Deciduous Teeth

Summary

This protocol describes the use of fluorescence-activated cell sorting of human mesenchymal stem cells using the single-cell sorting method. Specifically, the use of single-cell sorting can achieve 99% purity of the immunophenotyped cells from a heterogeneous population when combined with a multiparametric flow cytometry-based approach.

Abstract

The mesenchymal stem cells (MSCs) of an organism possess an extraordinary capacity to differentiate into multiple lineages of adult cells in the body and are known for their immunomodulatory and anti-inflammatory properties. The use of these stem cells is a boon to the field of regenerative biology, but at the same time, a bane to regenerative medicine and therapeutics owing to the multiple cellular ambiguities associated with them. These ambiguities may arise from the diversity in the source of these stem cells and from their in vitro growth conditions, both of which reflect upon their functional heterogeneity.

This warrants methodologies to provide purified, homogeneous populations of MSCs for therapeutic applications. Advances in the field of flow cytometry have enabled the detection of single-cell populations using a multiparametric approach. This protocol outlines a way to identify and purify stem cells from human exfoliated deciduous teeth (SHEDs) through fluorescence-assisted single-cell sorting. Simultaneous expression of surface markers, namely, CD90-fluorescein isothiocyanate (FITC), CD73-peridinin-chlorophyll-protein (PerCP-Cy5.5), CD105-allophycocyanin (APC), and CD44-V450, identified the "bright," positive-expressors of MSCs using multiparametric flow cytometry. However, a significant drop was observed in percentages of quadruple expressors of these positive markers from passage 7 onwards to the later passages.

The immunophenotyped subpopulations were sorted using the single-cell sort mode where only two positive and one negative marker constituted the inclusion criteria. This methodology ensured the cell viability of the sorted populations and maintained cell proliferation post sorting. The downstream application for such sorting can be used to evaluate lineage-specific differentiation for the gated subpopulations. This approach can be applied to other single-cell systems to improve isolation conditions and for acquiring multiple cell surface marker information.

Introduction

Mesenchymal stem cells (MSCs) can be regarded as a scalable source of cells suitable for cell-based therapies and may be considered a gold standard system in regenerative medicine. These cells can be isolated from a variety of sources in the body with different tissue origins¹. Depending on their source tissue, each type of MSC displays an ambiguous in vitro behavior². This is well observed in their morphological and functional properties³. Multiple studies have shown intra-clonal variation in dimensions, including adult tissue differentiation, genomic state, and metabolic and cellular ar....

Protocol

Ethics approval and consent to participate: Human exfoliated deciduous dental pulp samples were received after obtaining informed consent and full ethical approval by Sri Rajiv Gandhi Dental College and Hospital (SRGCDS) Oral and Maxillofacial Department, Bengaluru, in accordance with the standards established by the Hospital Ethical Clearance Committee, SRGCDS. Following which isolation, culture, maintenance, and application of SHEDs were approved by and in compliance with the guidelines recommended by the Institut.......

Discussion

In the field of tissue engineering and regenerative medicine, among the postnatal sources, oral tissue-derived MSCs have attracted profound interest because of their minimal ethical obligations and notable multilineage differentiation potential²¹. Dental pulp stem cells (DPSCs) from the impacted third molar and SHEDs have garnered the most attention among dental MSCs for their therapeutic potential in neurodegenerative and traumatic diseases²². The protocol described in thi.......

Materials

Name	Company	Catalog Number	Comments
Alcian Blue Stain	HiMedia	CCK029-1KT
Antibiotic-Antimycotic (100x)	Gibco by ThermoFisher	15240062
BD CompBead Plus Anti-Mouse Ig, κ/Negative Control (BSA) Compensation Plus (7.5 µm) Particles Set	BD Biosciences	560497
BD FACS Accudrop Beads	BD Biosciences	345249	Used to set up the Laser delay when the sort module opens.
BD FACS Aria Fusion Flow cytometer	BD Biosciences	---
BD FACS Diva 9.4	BD Biosciences	---
BD FACS Sheath Fluid	BD Biosciences	342003	Used as sheath fluid for both analysis and sorting experiments in the BD FACSAria Fusion
BD FACSDiva CS&T Research Beads	BD Biosciences	655050	Used for Instrument configuration depending on the nozzle size.
BD Horizon V450 Mouse Anti-Human CD44	BD Biosciences	561292
BD Horizon V450 Mouse IgG2b, κ Isotype Control	BD Biosciences	560374	CD44-V450 isotype
BD Pharmingen APC Mouse Anti-Human CD105	BD Biosciences	562408
BD Pharmingen APC Mouse IgG1, κ Isotype Control	BD Biosciences	555751	CD105-APC isotype
BD Pharmingen DAPI Solution	BD Biosciences	564907	DAPI Stock solution of 1 mg/mL
BD Pharmingen FITC Mouse Anti-Human CD90	BD Biosciences	555595
BD Pharmingen FITC Mouse IgG1, κ Isotype Control	BD Biosciences	555748	CD90-FITC isotype
BD Pharmingen PE Mouse Anti-Human CD45	BD Biosciences	555483
BD Pharmingen PE Mouse IgG1, κ Isotype Control	BD Biosciences	555749	CD45-PE isotype
BD Pharmingen PerCP-Cy 5.5 Mouse Anti-Human CD73	BD Biosciences	561260
BD Pharmingen PerCP-Cy 5.5 Mouse IgG1, κ Isotype Control	BD Biosciences	550795	CD73-PerCP-Cy 5.5 isotype
BD Pharmingen Purified Mouse Anti-Vimentin	BD Biosciences	550513
Bovine serum albumin	Hi-Media	TC548-5G
Crystal violet	Nice chemical pvt ltd	C33809
Dulbecco's Phosphate Buffered Saline	Sigma-aldrich	D5652-50L	dPBS used for culture work and maintenance.
Ethanol	---	---	Used for general sterlization.
Fetal Bovine Serum	Gibco by ThermoFisher	10270-106
Goat anti-Mouse IgG (H+L) Cross-Adsorbed Secondary Antibody, Alexa Fluor 555	ThermoFisher Scientific	A-21422
KO-DMEM	Gibco by ThermoFisher	10829018	Basal medium for undifferentiated hESCs, used in the preparation of culture media
L-Glutamine 200mM (100x)	Gibco by ThermoFisher	25030-081
Methanol, for Molecular Biology	Hi-Media	MB113
Oil red O	HiMedia	CCK013-1KT
Paraformaldehyde	loba chemie	30525-89-4
Penicillin Streptomycin (100x)	Gibco by ThermoFisher	15140- 122
Phalloidin (ActinGreen 488 ReadyProbes reagent)	Invitrogen	R37110
Silver Nitrate	HiMedia	MB156-25G
Sodium Thiosulphate pentahydrate	Chemport	10102-17-7
Sphero Rainbow Fluorescent Particles, 3.0 - 3.4 µm	BD Biosciences	556291
Staining buffer	Prepared in MIRM	----	It was prepared using 2% FBS in PBS
StemPro Adipogenesis Differentiation Basal Media	Gibco by ThermoFisher	A10410-01	Basal media for Adipogenic media
StemPro Adipogenesis Supplement	Gibco by ThermoFisher	A10065-01	Induction media for Adipogenic media
StemPro Chondrogenesis Supplement	Gibco by ThermoFisher	A10064-01	Induction media for Chondrogenic media
StemPro Osteogenesis Supplement	Gibco by ThermoFisher	A10066-01	Induction media for Osteoogenic media
StemPro Osteogenesis/Chondrogenesis Differentiation Basal Media	Gibco by ThermoFisher	A10069-01	Basal media for both Ostegenic and Chondrogenic media
Triton-X-100	Hi-Media	MB031
Trypan Blue	Gibco by life technologies	15250-061
Trypsin - EDTA Solution 1x	Hi-media	TCL049
Tween-20	MERCK	9005-64-5