β‐Adrenergic stimuli and rotating suspension culture enhance conversion of human adipogenic mesenchymal stem cells into highly conductive cardiac progenitors

Abstract

Clinical trials using human adipogenic mesenchymal stem cells (hAdMSCs) for the treatment of cardiac diseases have shown improvement in cardiac function and were proven safe. However, hAdMSCs do not convert efficiently into cardiomyocytes (CMs) or vasculature. Thus, reprogramming hAdMSCs into myocyte progenitors may fare better in future investigations. To reprogramme hAdMSCs into electrically conductive cardiac progenitor cells, we pioneered a three‐step reprogramming strategy that uses proven MESP1/ETS2 transcription factors, β‐adrenergic and hypoxic signalling induced in three‐dimensional (3D) cardiospheres. In Stage 1, ETS2 and MESP1 activated NNKX2.5, TBX5, MEF2C, dHAND, and GATA4 during the conversion of hAdMSCs into cardiac progenitor cells. Next, in Stage 2, β2AR activation repositioned cardiac progenitors into de novo immature conductive cardiac cells, along with the appearance of RYR2, CAV2.1, CAV3.1, NAV1.5, SERCA2, and CX45 gene transcripts and displayed action potentials. In Stage 3, electrical conduction that was fostered by 3D cardiospheres formed in a Synthecon®, Inc. rotating bioreactor induced the appearance of hypoxic genes: HIF‐1α/β, PCG 1α/β, and NOS2, which coincided with the robust activation of adult contractile genes including MLC2v, TNNT2, and TNNI3, ion channel genes, and the appearance of hyperpolarization‐activated and cyclic nucleotide‐gated channels (HCN1–4). Conduction velocities doubled to ~200 mm/s after hypoxia and doubled yet again after dissociation of the 3D cell clusters to ~400 mm/s. By comparison, normal conduction velocities within working ventricular myocytes in the whole heart range from 0.5 to 1 m/s. Epinephrine stimulation of stage 3 cardiac cells in patches resulted in an increase in amplitude of the electrical wave, indicative of conductive cardiac cells. Our efficient protocol that converted hAdMSCs into highly conductive cardiac progenitors demonstrated the potential utilization of stage 3 cells for tissue engineering applications for cardiac repair.

Direct reprogramming of cardiomyocytes into cardiac Purkinje-like cells

“…Forskolin and Rolipram have been used in numerous protocols of cell reprogramming and differentiation, and have been reported as “reprogramming facilitators” since they have been shown to promote cell fate plasticity ( Qin et al., 2017 ; Ma et al., 2017 ). Moreover, previous data from our lab (data not shown) suggested that the treatment of cardiac progenitor cells with Epinephrine resulted in the differentiation of the progenitor cells into cardiac conduction-like cells via the transcription activation of key CCS channel proteins including SCN5a ( Islas et al., 2020 ).…”

ERK1-mediated immunomodulation of mesenchymal stem cells ameliorates inflammatory disorders

“… 37 , 38 In MSCT, ETS genes have been reported as targets for the protection and regeneration of cardiac muscle and bone matrix by MSCs or their exosomes. 39 , 40 Therefore, we tested ETS2 expression, and the results of the luciferase and ChIP assays indicated that ETS2 expression was decreased in ERK1 −/− BMMSCs, suggesting that ETS2, especially the ETS2-2- and ETS2-3-predicted binding sites on the aurka promoter region, transfers the signal from ERK1 to AURKA. Combining all the evidence, we demonstrated that ERK1, but not ERK2, induced T cell apoptosis via the ETS2/AURKA/NF-κB/Fas cascade.…”

Artificial Scaffolds in Cardiac Tissue Engineering

“…One clear advantage of these materials is their help in promoting electrical conductivity, particularly in differentiating cells and other stimulants. Certain maturation properties are achieved, such as the induction of Purkinje-like cells [ 93 , 108 , 109 ]. Fibrin is a naturally occurring biomaterial, a biopolymer formed during coagulation [ 98 , 110 ].…”