Models with Marfan Syndrome: iPSC, Animal, and Tissue Approaches

Marfan syndrome is a genetic disorder affecting connective tissue, with complications primarily involving the cardiovascular, skeletal, and ocular systems. Research has advanced significantly through models that replicate its complex pathology, offering insights into disease mechanisms and potential treatments.

Various experimental approaches have been employed to study Marfan syndrome, each contributing unique advantages. Understanding these models is essential for improving therapeutic strategies and translating findings into clinical applications.

iPSC Derived Models

Induced pluripotent stem cell (iPSC) technology has transformed Marfan syndrome research by enabling patient-specific cellular models that replicate disease pathology in vitro. By reprogramming somatic cells, such as fibroblasts or peripheral blood mononuclear cells, into pluripotent stem cells, researchers can generate vascular smooth muscle cells (VSMCs), endothelial cells, and cardiomyocytes. These models provide a controlled environment to investigate the molecular and cellular mechanisms underlying connective tissue dysfunction, particularly in the cardiovascular system, where aortic aneurysm formation is a major concern.

A key advantage of iPSC-derived models is their ability to capture patient-specific genetic backgrounds, allowing for the study of genotype-phenotype correlations. For example, iPSC-derived VSMCs from Marfan syndrome patients exhibit increased matrix metalloproteinase (MMP) activity, leading to extracellular matrix degradation and heightened susceptibility to aneurysm formation. Aberrant transforming growth factor-beta (TGF-β) signaling, a hallmark of the disease, has also been observed, providing a platform to test targeted therapeutic interventions.

Beyond mechanistic insights, iPSC-derived models have facilitated drug screening efforts. High-throughput screening of small molecules using patient-derived VSMCs has identified compounds that stabilize extracellular matrix integrity and reduce TGF-β hyperactivation. For instance, losartan, an angiotensin II receptor blocker, has been tested in iPSC-derived aortic cells, confirming its role in attenuating pathological signaling and reinforcing its clinical use in Marfan syndrome patients.

Animal Models

Animal models have been instrumental in advancing the understanding of Marfan syndrome by replicating key pathological features observed in human patients. These models allow researchers to study disease progression, assess the impact of genetic mutations, and evaluate potential treatments.

Mouse

Murine models are widely used due to their genetic tractability and well-characterized cardiovascular system. The Fbn1^C1039G/+ mouse, which carries a heterozygous missense mutation in the fibrillin-1 (Fbn1) gene, exhibits hallmark features of the disease, including aortic root dilation, elastic fiber fragmentation, and increased TGF-β signaling. Studies using this model have demonstrated that TGF-β antagonism, through agents such as losartan, can mitigate aortic aneurysm progression, providing a foundation for clinical trials.

Conditional knockout models have also been developed to investigate tissue-specific roles of fibrillin-1, offering insights into the differential impact of the mutation on vascular, skeletal, and ocular systems. These genetically engineered mouse models have facilitated preclinical drug testing, enabling the evaluation of novel therapeutic strategies.

Zebrafish

Zebrafish models complement mammalian systems, particularly for studying early developmental processes and high-throughput drug screening. Genetic manipulation techniques, such as CRISPR-Cas9, have enabled the generation of zebrafish lines with fbn1 mutations, leading to craniofacial abnormalities, vascular defects, and altered extracellular matrix organization. The transparency of zebrafish embryos allows for real-time imaging of vascular development, facilitating the study of aortic pathology in vivo.

Zebrafish models have been used for rapid pharmacological screening, identifying compounds that modulate TGF-β signaling and extracellular matrix stability. Their short reproductive cycle and ease of genetic manipulation make them a valuable addition to Marfan syndrome research.

Rabbit

Rabbit models are relevant for studying aortic aneurysm formation due to their anatomical and physiological similarities to the human cardiovascular system. While genetically modified rabbit models are less common than murine models, induced models using fibrillin-1-targeting strategies have been developed to investigate vascular pathology. Rabbits exhibit elastic fiber architecture and hemodynamic properties that closely resemble those of humans, making them useful for studying aortic biomechanics and surgical interventions.

Experimental approaches, such as elastase-induced aortic aneurysm models, have provided insights into the structural vulnerabilities of the aortic wall. Imaging modalities such as ultrasound and MRI have been used to longitudinally assess disease progression. Rabbit models serve as a translational bridge between small animal models and human clinical studies, particularly in vascular pathology research.

Tissue Engineering Constructs

Advances in tissue engineering have enabled the recreation of key structural and mechanical properties of affected tissues. By leveraging biomaterials, cellular components, and biofabrication techniques, researchers have developed constructs that mimic the extracellular matrix (ECM) composition and biomechanical behavior of connective tissues compromised by fibrillin-1 mutations.

Hydrogel-based scaffolds replicate the microenvironment of the aortic wall, incorporating fibrillin-1-deficient extracellular matrix proteins to investigate their effects on cellular behavior. Studies have shown that VSMCs seeded onto these scaffolds exhibit altered adhesion, migration, and contractility, mirroring the dysfunction observed in Marfan syndrome. Bioactive hydrogels infused with signaling molecules such as TGF-β have been utilized to dissect the role of dysregulated pathways in ECM degradation.

Three-dimensional (3D) bioprinting has further expanded tissue-engineered models by enabling the fabrication of anatomically accurate vascular structures. Using patient-derived cells and ECM-mimetic biomaterials, researchers have successfully printed aortic tissues that exhibit elastic fiber fragmentation. These constructs allow for mechanical testing under physiological flow conditions and facilitate the development of tissue-engineered grafts for personalized surgical interventions.

Organ On Chip Platforms

Microfluidic organ-on-chip platforms replicate the biomechanical and biochemical microenvironments of affected tissues. These systems integrate living cells within microengineered channels that mimic physiological conditions, allowing researchers to study disease mechanisms with greater precision than traditional in vitro models.

Aortic-on-chip models recreate the interactions between VSMCs, endothelial cells, and extracellular matrix components under physiological flow conditions. These systems enable real-time monitoring of cellular responses to mechanical stress, revealing how fibrillin-1 mutations disrupt vascular integrity. Studies have shown that Marfan syndrome-derived VSMCs exhibit abnormal cytoskeletal organization and increased susceptibility to matrix degradation when exposed to pulsatile flow.

Organ chips also provide a unique platform for testing pharmacological interventions, allowing for the continuous perfusion of drug candidates while assessing their effects on cellular behavior and matrix stability.

Genome Editing Techniques

Genome editing technologies have revolutionized Marfan syndrome research by enabling precise alterations to the fibrillin-1 (FBN1) gene. Tools such as CRISPR-Cas9 allow researchers to introduce targeted mutations in cellular and animal models, facilitating the study of disease mechanisms in a controlled manner. This has provided critical insights into how structural deficiencies in fibrillin-1 contribute to extracellular matrix instability and aortic aneurysm formation.

Beyond modeling the disease, genome editing holds promise for therapeutic intervention. CRISPR-based approaches have been explored to correct pathogenic FBN1 mutations at the genomic level, with preliminary studies demonstrating successful gene repair in patient-derived cells. Base editing, a more refined variant of CRISPR, has been used to directly modify single nucleotide variants associated with Marfan syndrome, potentially reducing off-target effects.

While these gene-editing strategies remain in the experimental stage, advancements in delivery mechanisms, such as adeno-associated virus (AAV) vectors and lipid nanoparticles, are improving their feasibility for clinical application. If optimized for safety and efficacy, these technologies could pave the way for gene therapies aimed at mitigating disease progression in individuals with Marfan syndrome.