Generation of Induced Pluripotent Stem Cell-Derived iTenocytes via Combined Scleraxis Overexpression and 2D Uniaxial Tension

Summary

This article describes a procedure to produce iTenocytes by generating iPSC-derived mesenchymal stromal cells with combined overexpression of Scleraxis using a lentiviral vector and uniaxial stretching via a 2D bioreactor.

Abstract

Today's challenges in tendon and ligament repair necessitate the identification of a suitable and effective candidate for cell-based therapy to promote tendon regeneration. Mesenchymal stromal cells (MSCs) have been explored as a potential tissue engineering strategy for tendon repair. While they are multipotent and have regenerative potential in vivo, they are limited in their self-renewal capacity and exhibit phenotypic heterogeneity. Induced pluripotent stem cells (iPSCs) can circumvent these limitations due to their high self-renewal capacity and unparalleled developmental plasticity. In tenocyte development, Scleraxis (Scx) is a crucial direct molecular regulator of tendon differentiation. Additionally, mechanoregulation has been shown to be a central element guiding embryonic tendon development and healing. As such, we have developed a protocol to encapsulate the synergistic effect of biological and mechanical stimulation that may be essential for generating tenocytes. iPSCs were induced to become mesenchymal stromal cells (iMSCs) and were characterized with classic mesenchymal stromal cell markers via flow cytometry. Next, using a lentiviral vector, the iMSCs were transduced to stably overexpress SCX (iMSC^SCX+). These iMSC^SCX+ cells can be further matured into iTenocytes via uniaxial tensile loading using a 2D bioreactor. The resulting cells were characterized by observing the upregulation of early and late tendon markers, as well as collagen deposition. This method of generating iTenocytes can be used to assist researchers in developing a potentially unlimited off-the-shelf allogeneic cell source for tendon cell therapy applications.

Introduction

To tackle the contemporary issues in tendon and ligament repair, there's a requirement for a pertinent cell candidate suitable for cell-based therapies. One avenue of investigation in tissue engineering for tendon repair involves the exploration of bone marrow-derived mesenchymal stromal cells (BM-MSCs) and adipose tissue-derived stromal cells (ASCs) as potential strategies. These cells have multipotent capability, great abundance, and regenerative potential in vivo. Additionally, they have shown enhanced healing capacity and improved functional outcomes in animal models¹. Nonetheless, these cells exhibit restricted self-renewal ca....

Protocol

This protocol to produce iTenocytes can be conducted in three major steps: iPSCs to iMSCs (10 days), iMSC to iMSC^SCX+ (2 weeks), iMSC^SCX+ to iTenocytes (minimum 4 days). Each major step in the protocol can be paused and restarted later, depending on the experimental timeline. For methods involved with culturing of cells, sterile techniques should be employed. All cells in this protocol should be grown at 37 °C, 5% CO₂, and 95% humidity.

1. Human iPSC.......

Discussion

In this protocol, iTenocytes are generated through three main steps: (1) induction of iPSCs to iMSCs, (2) overexpression of SCX using a lentiviral vector, and (3) maturation of cells through 2D uniaxial tension.

The protocol presented for differentiating iPSCs into iMSCs has been previously described by our group². Since that publication, numerous protocols have been developed, including an established protocol for using iMSCs in clinical trials²¹

Materials

Name	Company	Catalog Number	Comments
2-mercaptoethanol	Sigma Aldrich	M3148
Accutase	StemCell Technologies	7920	cell dissociation reagent
Antibiotic-antimycotic solution	Thermofisher	15240096
Anti-CD105	Ancell	326-050
APC mouse anti-human CD44	BD Biosciences	559942
APC mouse IgG2 K isotype control	BD Biosciences	555745
BenchMark fetal bovine serum	GeminiBio	100-106
Biglycan	Thermofisher	Hs00959143_m1
Bovine serum albumin	Millipore Sigma	A3733
Collagen type I alpha 1 chain human Taqman primer	Thermofisher	Hs00164004_m1
Collagen type III alpha 1 chain human Taqman primer	Thermofisher	Hs00943809_m1
Dimethyl sulfoxide	Millipore Sigma	D8418
DMEM, low glucose, pyruvate, no glutamine, no phenol red	Thermofisher	11054020
Eagle's minimum essential medium (EMEM)	ATCC	30-2003
Fibronectin bovine plasma	Sigma Aldrich	F1141
FITC mouse anti-human CD90	BD Biosciences	555595
Gelatin from porcine skin	Sigma Aldrich	G1890
Goat anti Mouse IgG1-PE	Bio-Rad	STAR117
HEK 293T/17	ATCC	CRL-11268
IMDM, no phenol red	Thermofisher	21056023
iPSCs: 83i-cntr-33n1	Cedars-Sinai iPSC Core Facility	N/A	https://biomanufacturing.cedars-sinai.org/product/cs83ictr-33nxx/
Isotype Control Antibody, mouse IgG2a-FITC	Miltenyi Biotec	130-113-271
KnockOut serum replacement	Thermofisher	10828010
L-ascorbic acid	Sigma Aldrich	A4544
L-Glutamine	Thermofisher	2503081
Matrigel	Corning	354230	basement membrane matrix
MechanoCulture FX	CellScale	N/A	stretching apparatus
MEM non-essential amino acids solution	Thermofisher	11140050
Mohawk human Taqman primer	Thermofisher	Hs00543190_m1
mTeSR Plus	StemCell Technologies	100-0276
PBS	Thermofisher	10010023
Platelet-derived growth factor receptor A human Taqman primer	Thermofisher	Hs00998018_m1
Poly(2-hydroxyethyl methacrylate)	Sigma Aldrich	192066
Polybrene infection/transfection reagents	Millipore Sigma	TR-1003
Recombinant human  TGF-beta 1 protein human Taqman primer	RnD Systems	240-B
Scleraxis human Taqman primer	Thermofisher	Hs03054634_g1
SCXA (SCX) (NM_00108050514) human tagged ORF clone	OriGene	RC224305L4
Silicone plates	CellScale	N/A
Sodium azide	Millipore Sigma	S2002
Tenascin C human Taqman primer	Thermofisher	Hs00370384_m1
Tenomodulin human Taqman primer	Thermofisher	Hs00223332_m1
Thrombospondin 4 human Taqman primer	Thermofisher	Hs00170261_m1
Transfection reagent, BioT	Bioland Scientific LLC	B01-01
Trypsin-EDTA (0.25%)	Thermofisher	25200072
Tubulin polymerization promoting protein family member 3	Thermofisher	Hs03043892_m1
Y-27632 dihydrochloride	Biogems	1293823