Periodic Reporting for period 5 - BIORECAR (Direct cell reprogramming therapy in myocardial regeneration through an engineered multifunctional platform integrating biochemical instructive cues)
Reporting period: 2024-01-01 to 2025-02-28
An ideal cardiac regenerative medicine strategy should replace lost cardiomyocytes and recover myocardial functional contractility. Many advanced therapies under investigation, such as cell therapies and tissue engineering approaches, have achieved limited success [1]. Therefore, the regeneration of a damaged heart still remains a major clinical challenge with a deep social and economic impact.
Direct reprogramming strategy, aimed at the direct conversion of cells populating the cardiac scar (i.e. cardiac fibroblasts) into beating cells (i.e. cardiomyocytes) has emerged as a new intriguing possibility for myocardial regeneration. Despite the excitement on the potentiality of direct cell reprogramming for cardiac regeneration, the approach is still immature and inefficient to prospect a short-term clinical translation [1].
BIORECAR project addressed the current limitations of direct cell reprogramming by a novel multifunctional approach, involving a multidisciplinary team and integrating tools from nanomedicine, biomaterials science and tissue engineering, with the aim to achieve a significant advancement in the knowledge of direct cell reprogramming in the perspective of a future clinical application.
In BIORECAR, direct reprogramming was studied by the release of small RNA molecules, called microRNAs (miRNAs) to the cells populating cardiac scar. A combination of four miRNAs, called miRcombo was used to modify the behavior of cardiac fibroblasts inducing their reprogramming into cardiomyocytes.
The overall project aim (Figure 1) was achieved through:
Objective 1: The design of polymer nanoparticles, loaded with miRcombo, for a targeted and efficient direct reprogramming of human cardiac fibroblasts into cardiomyocytes;
Objective 2: The design of a multifunctional injectable hydrogel releasing nanoparticles and increasing direct reprogramming efficiency, for a minimally invasive approach in cardiac regeneration;
Objective 3: The development of biomimetic in vitro models of human cardiac fibrotic tissue for the testing and validation of BIORECAR approach, before the final in vivo trials in mouse model (Figure 2).
Objective 4: Preclinical validation of BIORECAR approach in mouse model.
Being heart failure the leading cause of mortality and morbidity in the industrialized world, any new knowledge on its effective treatment achieved in BIORECAR is expected to have a deep social and economic impact.
Additionally, beyond post-myocardial infarction treatment, BIORECAR approach could treat other forms of acquired or inherited heart disease associated with fibrosis, further increasing the project impact.
Objective 1: Design of polymeric nanoparticle for direct reprogramming
MiRcombo-mediated direct cardiac reprogramming of human adult cardiac fibroblasts into cardiomyocytes was studied [2]. Novel lipid-based nanoparticles were developed, able to efficiently encapsulate and release miRNAs to human cardiac fibroblasts for direct reprogramming [3]. Hybrid polymer-lipid nanoparticles were formulated and patented, showing a high encapsulation ability, biocompatibility and efficient transfection of human adult cardiac fibroblasts [4]. They represent promising candidates for in situ treatment, as demonstrated by in vitro tests using human cardiac fibrotic tissue models and by in vivo trials in mouse models.
Objective 2: Injectable hydrogel maximizing direct reprogramming efficiency.
MiRcombo-mediated direct reprogramming of human cardiac fibroblasts was enhanced by culturing cells in biomimetic 3D hydrogels respect to 2D substrates [5].
Injectable hydrogels were prepared by blending a biocompatible biodegradable polymer with tailored stability, and a biomimetic polymer favoring cell attachment and transdifferentiation into cardiomyocyte-like cells.
In detail self-healing injectable hydrogels were designed and widely characterized [6].
Objective 3: In vitro models of human cardiac fibrotic tissue.
In vitro models of human infarcted tissue were prepared by tissue engineering, exploiting "bioartificial" scaffolds combining synthetic and natural polymers [7-9].
We also collaborated to the design of a beating human cardiac scar on a chip for direct reprogramming testing [10].
Objective 4: Preliminary validation in mouse model.
In vivo tests were performed in mouse models of myocardial infarction showing promising biodistribution and efficacy of BIORECAR nanoparticles.
For each project objective, progresses beyond the state of the art and expected results are the following:
Objective 1:
-Demonstration of miRcombo ability to trigger human cardiac fibroblasts reprogramming into cardiomyocytes [2-5, 10].
-Design of lipoplexes for efficient miRcombo encapsulation and release to human cardiac fibroblasts, with enhanced biocompatibility and efficacy respect to commercial agents [3,10].
-Design and patenting of new hybrid polymer-lipid nanoparticles [4] with:
-(i) high miRNA loading ability, transfection efficiency, and stability in physiological conditions;
(ii) cardiac fibroblasts-release ability by surface functionalization with a specific ligand.
Objective 2:
- Evidence of higher direct reprogramming efficiency for cells cultured in a biomimetic 3D hydrogel [5].
- Innovative design of injectable multi-functional hydrogels [6] for miRNA-loaded nanoparticle release.
Objective 3:
- Novel in vitro models mimicking human cardiac fibrotic tissue for preclinical testing of BIORECAR approach [7-10].
Objective 4:
- Promising in vivo biodistribution and efficacy for functionalized nanoparticles.
[1] Paoletti et al. Cells 2018; 7(9), 114.
[2] Paoletti et al. Front. Bioeng. Biotechnol. 2020; 8: 529.
[3] Nicoletti and Paoletti et al. Nanomedicine 2022; 45: 102589.
[4] Nicoletti et al. Adv. Healthc. Mater. 2025 (accepted).
[5] Paoletti et al. Cells 2022; 11(5), 800.
[6] Stola et al. IJB 2024; 10(6), 4014.
[7] Spedicati et al. Front. Bioeng. Biotechnol. 2022; 10, https://doi.org/10.3389/fbioe.2022.983872(opens in new window)
[8] Ruocco et al. ACS Biomater Sci Eng 2023; 9(7): 4368
[9] Spedicati et al. IJB 2024; 10(3): 2247.
[10] Visone and Paoletti et al. Adv. Healthc. Mater. 2024; 13(4): e2301481.
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