Assessment of cardiovascular effects of nicotine in using human induced pluripotent stem cell-derived endothelial cells from identical twins
Authors: Bors L A , Szabo E , Orsolits B , Merkely B , Apati A , Molnar A A , Foldes G 
Published: June 2022

Abstract

Funding Acknowledgements
Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Hungarian National Research, Development and Innovation Fund

Introduction
Smoke-induced diseases cause 20% of global mortality. The toxic agents of cigarette smoke have notorious destructive effects on the cardiovascular system. Therefore, many people use e-cigarettes instead of traditional tobacco products; yet, nicotine content remains the cause of addiction.

Purpose
Human induced pluripotent stem cells (hiPSC) provide a useful personalised link between clinical and in vitro cardiovascular models. Here we generated hiPSC lines from a pair of identical twins with diabetes to test long and short-term effects of nicotine.

Methods
Blood samples were used to reprogram mononuclear cell fractions into hiPSC via Sendai viral transduction of the Yamanaka factors (Cytotune 2.0). Genotype and pluripotency of the iPSC were checked with FACS, PCR, immunocytochemistry and embryoid body formation. hiPSC line from non-diabetic healthy control ("GM") was used as control. The hiPSC lines were differentiated into endothelial cells and used in a toxicology and phenotypic assays. hiPSC-derived endothelial cells and control HUVEC were treated with e-cigarette liquid with (nicotine 0.225 mg/ml, ECL18) and without nicotine (ECL0) or nicotine in culture medium (0.225 mg/ml). The cells were analysed with high content microscopy (HCS, Opera), using Hoechst, apoptotic marker caspase3/7, mitochondrial TMRM and endothelial CD31 labelling.

Results
On the clinical side, one of the diabetic twins was a smoker ("C") and diagnosed and treated with a severe coronary disease, whilst the other ("D") was a non-smoker and no coronary artery disease. For the reprogrammed twin clones (normal, 46XX chromosomes), no differences in exome sequence were found. Cells were positive for pluripotency marker SSEA4 (&gt;90%, FACS); Oct4 and Nanog were also positive, embryoid body formation and PCR were positive for all the three germ layers. The phenotypic fidelity of hiPSC-derived endothelial cells (hiPSC-EC) were different from the twin lines. C cell line showed a higher endothelial-to-mesenchymal transition rate and non-endothelial drift as compared to D line at 3 passages FACS after CD31 isolation (9% CD31+ vs 37% and 41%, for C, D and non-diabetic control, respectively). Nicotine did not change TMRM or caspase 3/7 activation in "C" hiPSC-EC, in turn it induced apoptosis in "D" cells (p=0.01 vs ECL18 and p=0.02 vs EGM2+nicotine, n=3). In GM and HUVEC endothelial cells, TMRM intensity increased after e-cigarette liquid treatment (all p&lt;0.05, n=3) and caspase was higher group with ECL containing nicotine (p = 0.0178, n=3).
"D" line endothelial cells showed higher cell loss to the nicotine diluted in EGM2, than in ECL (p = 0.0091, n=6).

Conclusions
Our developed a novel patient-specific hiPSC model where and in vitro toxicology assay showed alteration in endothelial phenotype associated with nicotine exposure. A scalable platform can provide further cohort level information on toxic agent like nicotine to the cardiovascular system.