Biology subjects

Ozcebe, S. G.

Publications and source records attributed to Ozcebe, S. G..

3 recordsLinked to original sources

bioRxiv2023

Adult Human Heart ECM Improves Human iPSC-CM Function via Mitochondrial and Metabolic Maturation

Myocardial infarction can lead to the loss of billions of cardiomyocytes, and while cell-based therapies are a promising option, the immature nature of in vitro-generated human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMs) is a significant roadblock to their development. Through the years, various approaches have emerged to improve iCM maturation, yet none could fully recapitulate the complexity of cardiac development and were not enough to achieve full cardiac maturity in vitro. Cardiac differentiation occurs at the early stages of development in a highly dynamic environment. Although significantly improved over the past two decades, small molecule-based iPSC differentiation protocols dont go beyond producing high purity fetal iCMs. Recently adult extracellular matrix (ECM) was shown to retain tissue memory and has shown some success in driving tissue-specific differentiation in unspecified cells in various organ systems. Therefore, here, we first characterized the adult human heart left ventricle components. We then investigated the effect of adult human heart-derived ECM on iPSC cardiac differentiation and subsequent maturation. By preconditioning iPSCs with ECM, we tested whether creating a cardiac environment around iPSCs would drive them toward cardiac fate before small molecule mediated differentiation. Ultimately, we investigated ECM components that might be responsible for the observed effects. We identified critical glycoproteins and proteoglycans involved in early cardiac development in the adult heart ECM. Namely, adult ECM had extracellular galactin-1, fibronectin, fibrillins, and basement-membrane-specific heparan-sulfate proteoglycan (HSPG), which have been implicated in normal heart development and associated with various embryonic developmental processes. Relatedly, we showed that preconditioning iPSCs with adult ECM resulted in enhanced cardiac differentiation, yielding iCMs with higher functional maturity. Further investigation revealed that a more developed mitochondrial network and coverage as well as enhanced metabolic maturity and a shift towards a more energetic profile allowed the observed functional enhancement in ECM pretreated iCMs. These findings demonstrate the potential of using cardiac ECM for promoting iCM maturation and suggest a promising strategy for improving the development of iCM-based therapies and in vitro cardiac disease modeling and drug screening studies. Upon manipulating ECM, such as heat denaturation and sonication to eliminate protein components and release ECM bound vesicle contents, respectively, we concluded that the beneficial effects that we observed are not solely due to the ECM proteins, and might be related to the decorative units attached to them.

bioengineering↗

bioRxiv2023

In Need of Age-Appropriate Cardiac Models: Impact of Cell Age on Extracellular Matrix Therapy Outcomes

Aging is the main risk factor for cardiovascular disease (CVD). As the worlds population ages rapidly and CVD rates rise, there is a growing need for physiologically relevant models of aging hearts to better understand cardiac aging. Translational research relies heavily on young animal models, however, these models correspond to early ages in human life, therefore cannot fully capture the pathophysiology of age-related CVD. Here, we chronologically aged human induced pluripotent stem cell-derived cardiomyocytes (iCMs) and compared in vitro iCM aging to native human cardiac tissue aging. We showed that 14-month-old advanced aged iCMs had an aging profile similar to the aged human heart and recapitulated age-related disease hallmarks. We then used aged iCMs to study the effect of cell age on the young extracellular matrix (ECM) therapy, an emerging approach for myocardial infarction (MI) treatment and prevention. Young ECM decreased oxidative stress, improved survival, and post-MI beating in aged iCMs. In the absence of stress, young ECM improved beating and reversed aging-associated expressions in 3-month-old iCMs while causing the opposite effect on 14-month-old iCMs. The same young ECM treatment surprisingly increased SASP and impaired beating in advanced aged iCMs. Overall, we showed that young ECM therapy had a positive effect on post-MI recovery, however, cell age was determinant in the treatment outcomes without any stress conditions. Therefore, "one-size-fits-all" approaches to ECM treatments fail, and cardiac tissue engineered models with age-matched human iCMs are valuable in translational basic research for determining the appropriate treatment, particularly for the elderly.

bioengineering↗

bioRxiv2021

Tunable human myocardium derived decellularized extracellular matrix for 3D bioprinting and cardiac tissue engineering

The generation of 3D tissue constructs with multiple cell types and matching mechanical properties remains a challenge in cardiac tissue engineering. Recently, 3D bioprinting has become a powerful tool to achieve these goals. Decellularized extracellular matrix (dECM) is a common scaffold material due to providing a native biochemical environment. Unfortunately, dECMs low mechanical stability prevents usage for bioprinting applications alone. In this study, we developed bioinks composed of decellularized human heart ECM (dhECM) with either gelatin methacryloyl (GelMA) or GelMA- methacrylated hyaluronic acid (MeHA) hydrogels dual crosslinked with UV light and microbial Transglutaminase (mTGase). We characterized the bioinks mechanical, rheological, swelling, printability and biocompatibility properties. Composite GelMA-MeHA-dhECM (GME) hydrogels demonstrated improved mechanical properties by an order of magnitude, compared to GelMA-dhECM (GE) hydrogels. All hydrogels were extrudable and compatible with human induced pluripotent stem cells derived cardiomyocytes (iCMs) and human cardiac fibroblasts (hCFs). Tissue-like beating of the printed constructs with striated sarcomeric alpha-actinin and Connexin 43 expression was observed. The order of magnitude difference between the elastic modulus of these hydrogel composites offers applications in in vitro modelling of the myocardial infarct boundary. Here, as a proof of concept, we created an infarct boundary region with control over mechanical properties along with cellular and macromolecular content through printing iCMs with GE bioink and hCFs with GME bioink.

bioengineering↗