Targeting HIF-1α in combination with PPARα activation and postnatal factors promotes the metabolic maturation of human induced pluripotent stem cell-derived cardiomyocytes

Abstract

Immature phenotypes of cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) limit the utility of these cells in clinical application and basic research. During cardiac development, postnatal cardiomyocytes experience high oxygen tension along with a concomitant downregulation of hypoxia-inducible factor 1α (HIF-1α), leading to increased fatty acid oxidation (FAO). We hypothesized that targeting HIF-1α alone or in combination with other metabolic regulators could promote the metabolic maturation of hiPSC-CMs. We examined the effect of HIF-1α inhibition on the maturation of hiPSC-CMs and investigated a multipronged approach to promote hiPSC-CM maturation by combining HIF-1α inhibition with molecules that target key pathways involved in the energy metabolism. Cardiac spheres of highly-enriched hiPSC-CMs were treated with a HIF-1α inhibitor alone or in combination with an agonist of peroxisome proliferator activated receptor α (PPARα) and three postnatal factors (triiodothyronine hormone T3, insulin-like growth factor-1 and dexamethasone). HIF-1α inhibition significantly increased FAO and basal and maximal respiration of hiPSC-CMs. Combining HIF-1α inhibition with PPARα activation and the postnatal factors further increased FAO and improved mitochondrial maturation in hiPSC-CMs. Compared with mock-treated cultures, the cultures treated with the five factors had increased mitochondrial content and contained more cells with mitochondrial distribution throughout the cells, which are features of more mature cardiomyocytes. Consistent with these observations, a number of transcriptional *

Mitochondria and metabolic transitions in cardiomyocytes: lessons from development for stem cell-derived cardiomyocytes

“…However, during later stages of differentiation, inhibition of HIF-1α has beneficial effects, enhancing contractile, electrophysiologic, and metabolic maturation of PSC-CMs and also leading to downregulation of LDH [3,39]. These differential effects during early and late cardiomyocyte differentiation reflect the changing role of HIFs at the time of birth and during the perinatal metabolic switch.…”

“…Because in vitro culture is usually performed in atmospheric conditions, small molecules or metabolic stimuli have been used to inhibit HIF-1α in culture (rather than manipulating oxygen levels). Treatment of human PSC-CMs with chetomin [3], FM19G11 [39,40], or glucose-free, fatty acid-containing media [3] reduces HIF-1α and LDH expression and improves maturation of PSC-CMs. Hypoxia promotes a perinuclear distribution of mitochondria to promote ROS-mediated nuclear regulation [24].…”

“…Dexamethasone (1 μmol/L = 392 ng/mL, 24-72 h) promotes electrophysiologic maturation of hESC-CMs with accelerated calcium transient decay, enhanced function of the Na + -Ca 2+ exchanger (NCX) and sarco-endoplasmic reticulum calcium-ATPase (SERCA), and enhanced contractility [84]. Similarly, treatment of PSC-CMs with a combination of dexamethasone (1 μM) and T3 (100 nM), with [39,85] or without [78] insulin-like growth factor 1 (IGF-1; 100 ng/mL) for 1-2 weeks promotes cardiomyocyte maturation. While glucocorticoids are important in normal cardiac development, they can also have detrimental effects in other models [86]-for example, chronic, supraphysiologic doses of glucocorticoids can increase the risk of cardiovascular disease in adults [87]-thus, further work is necessary to understand the optimal duration of treatment to maximize PSC-CM maturation without inducing deleterious effects of glucocorticoids.…”

Maturing iPSC-Derived Cardiomyocytes

“…A question that was not pointedly addressed by Horikoshi and colleagues in their report is the underlying mechanism as to how a fatty acid-enriched, no-glucose medium could induce hiPSC-CMs maturation. PPARα is known to play a critical role in cardiomyocyte maturation, and PPARα agonists have been shown to promote cardiomyocyte maturation [12,13]. Furthermore, glucose is known to suppress the expression of PPARα [14].…”

Transcriptional regulation of mammalian heart regeneration

“…In support of this finding, during neonatal regeneration, YAP and the TF Pitx2 coordinate upregulation of endogenous reactive oxygen species scavengers, which maintains neonatal cardiomyocyte proliferative capacity (Tao et al, 2016). Conversely, pharmacological inhibition of the hypoxia-inducible factor 1α (Hif1a) in human PSC-derived cardiomyocytes, enhanced fatty acid oxidation and cardiomyocyte maturation (Gentillon et al, 2019). In fact, adult mice housed in hypoxic conditions (7% O2), exhibited mitigated fibrosis, improved cardiac function and augmented cardiomyocyte proliferation following myocardial infarction (Nakada et al, 2017).…”