An iPSC-derived functional bio-inspired scaffold for modelling the structure and the effects of extracellular matrix in cardiac fibrosis

Interstitial fibrosis is a pathological condition that leads to the remodelling of cardiac chambers following the clinical manifestation of different heart pathologies, and it strongly contributes to pump failure. The central orchestrators of fibrosis onset and progression are cardiac fibroblasts (cFbs). cFbs are specialized in maintaining the structural framework of the tissue and can sense specific molecular signals during cardiac injury that lead to their phenotype switch into activated cFbs or myofibroblastsMyofibroblasts are stress fibre-expressing cells specialized in repairing the damage by secreting the extracellular matrix (ECM) and remodelling the architecture of the tissue. The newly formed ECM plays a pivotal role in preserving the heart function by enriching the injury site with matricellular proteins and growth factors involved in promoting proliferative and regenerative signalling. However, during the late stage of fibrosis, myofibroblasts undergo apoptosis, the ECM stiffens, becoming more rigid, and the abundant matrix infiltrates between the still functional CMs, thus leading to arrhythmic events which compromise the heart function. The lack of myocardial fibrosis models able to recapitulate human pathophysiology and that look at the specific genetic background of the patients limits the implementation of suitable and efficient therapeutic strategies. Induced pluripotent stem cells (iPSCs) are a valid alternative to the use of animal models and primary cell lines, given the multitude of well-established protocols for the differentiation of cardiac cells. Another factor that has limited understanding of the processes responsible for cardiac fibrosis lies in the challenges posed by the study of the molecular mechanisms underlying the interaction between CMs and fibrotic ECM. This is mainly ascribed to the lack of a reliable cell culture scaffold able to mimic the cardiac microenvironment. Commonly used recombinant proteins such as fibronectin (FN), laminin (LAM), vitronectin (VNT) and collagen (COL), or matrices like Matrigel ™ and Cultrex ™ showed substantial benefits in the culture of iPSCs-derived cardiac cells. Nevertheless, they provide different mechanical stimuli compared to those the cells receive in vivo. In this context, different techniques of decellularization have been implemented to remove the cellular component from the tissue, organ or cell culture and isolate the ECM of interest to use it as an alternative scaffold for cell growth. In this project, we generated an isogenic patient-specific model based on the use of induced pluripotent stem cells (iPSCs) to investigate the changes occurring in the biochemical composition and architecture of the ECM during cardiac fibrosis progression and study their effects on cardiomyocytes (CMs) physiology. The developed model opens new scenarios for studying a wide spectrum of cardiac disorders and performing screening tests in a microenvironment that better recapitulates the complex in vivo pathophysiology of cardiac fibrosis.

Guest Speaker: Dr Francesco Niro

Postdoc from Giancarlo Forte’s group, SCMMS, KCL

Francesco Niro was born in Pescara on the 27th of September 1995. He graduated in Biological Sciences (bachelor) at Università degli Studi dell’Aquila in 2017. In February 2020, he obtained his Master's degree in Biology Applied to Research in Biomedicine at Università degli Studi di Milano with full marks and honours. During his Master's studies, he joined the Unit of Vascular Biology and Regenerative Medicine of Professor Giulio Pompilio in Centro Cardiologico Monzino, where he worked on a research project focused on using iPSCs to model Duchenne muscular dystrophy-associated cardiomyopathy. In August 2020, he won a PhD position in SINERGIA, a project funded by the European Union in the framework of the H2020 Marie Skłodowska Curie Actions – Innovative Training Networks, joining the Mechanobiology for Diseases group of Professor Giancarlo Forte at the International Clinic Research Center (ICRC) of St. Anne's University Hospital Brno (Czech Republic). Between 2020 and 2024, he had the opportunity to join again Professor Giulio Pompilio’s group in Milan and the School of Cardiovascular and Metabolic Medicine & Sciences (King’s College London) headed by Professor Mauro Giacca for short-term collaborations. Currently, Francesco is working in Brno aiming to finish his PhD journey within June 2024.