Rare cranial disorders: Towards a non-invasive therapy using gene silencing delivered by nanoparticles and 3D printing

A “gene silencer” (technically known as small interfering RNA, or siRNA), locally delivered by nanoparticles embedded in an injectable gel produced through 3D printing, can switch off the defective gene responsible for serious rare diseases known as craniosynostoses. These conditions are characterized by malformations of the skull and are currently treatable only through highly invasive surgical procedures performed in newborns and often repeated throughout childhood.

This is the promise emerging from studies coordinated by Professor Wanda Lattanzi, Associate Professor of Cellular and Applied Biology at Università Cattolica del Sacro Cuore (Rome campus) and medical geneticist at the Pediatric Neurosurgery Unit of the Fondazione Policlinico Universitario Agostino Gemelli IRCCS. The results have recently been published in the journals Molecular Therapy – Nucleic Acids and Regenerative Biomaterials.

Background

Craniosynostoses are congenital craniofacial developmental disorders caused by the premature ossification and closure of cranial sutures—the elastic regions that converge at the so-called fontanelles—resulting in restricted growth of the brain and other structures within the skull. The most severe forms are rare genetic diseases, such as Crouzon syndrome, which occurs in approximately 16.5 cases per million live births. This condition is characterized by marked skull and facial deformities leading to progressive impairments in vision, hearing, and breathing, which can become life-threatening if not treated early.

Crouzon syndrome is mainly caused by mutations in the fibroblast growth factor receptor 2 (FGFR2) gene, which lead to pathological acceleration of bone formation at the cranial sutures and rapid depletion of the resident stem cell population. FGFR2 mutations typically arise de novo—meaning that the patient carries the mutation while the parents do not—making most cases sporadic and prenatal diagnosis particularly challenging. As a result, the disease is usually diagnosed at birth through physical examination, imaging techniques, and genetic testing. Current therapeutic protocols involve multiple surgical procedures starting within the first months of life, including neurosurgical expansion to decompress the skull and reduce pressure on the developing brain, thereby minimizing associated complications.

For many years, the research group coordinated by Professor Lattanzi at the Section of Cellular and Applied Biology (Director: Professor Ornella Parolini), within the Department of Life Sciences and Public Health, has been investigating the mechanisms underlying genetic diseases, with a particular focus on bone stem cells as key players and potential therapeutic targets. This work has been carried out in close collaboration with Professor Alessandro Arcovito, Full Professor in the Department of Basic Biotechnological Sciences, Intensive Care and Perioperative Clinical Sciences, whose research focuses on the development of biocompatible “nanoparticles”—microscopic carriers already used in medicine—to deliver drugs precisely and in a controlled manner to the specific cells where they are needed.

This translational research is intrinsically rooted in close collaboration with the surgical team of the Pediatric Neurosurgery Unit at Policlinico Gemelli, directed by Professor Gianpiero Tamburrini. This unit is a national and international reference center for the multidisciplinary care of patients with craniosynostosis and is part of the European Reference Network for rare and complex craniofacial diseases (ERN CRANIO).

Over the years, these studies have enabled an in-depth understanding of the genetic and cellular mechanisms leading to premature suture ossification in craniosynostosis and, more recently, the development of innovative non-invasive therapeutic approaches.

From Gene Silencing to a 3D-Printed Therapeutic Platform

The most recent findings were published in Molecular Therapy – Nucleic Acids. In this study, led by Dr Federica Tiberio, a young researcher in Cellular and Applied Biology at the Department of Life Sciences and Public Health, gene-silencing molecules targeting the mutated gene were developed in the form of small interfering RNAs (siRNAs). These siRNAs were shown to restore proper gene function, thereby preventing premature ossification of cranial sutures. The study demonstrated that siRNAs can correct the function of the mutated gene and restore the vitality of patients’ stem cells, maintaining cranial sutures in an open state.

The most innovative aspects of this biotechnological approach lie in its high level of personalization—siRNAs are specifically designed to correct the individual genetic defect identified in each patient—and in their ability to selectively silence only the mutated version (“allele”) of the gene without affecting the healthy counterpart, which is essential for normal cellular and tissue function.

To translate this technology into clinical application, the same team subsequently completed a new study, published in Regenerative Biomaterials, integrating siRNAs into a tissue-engineering strategy. Young researchers Martina Salvati, Federica Tiberio, and Noah Giacon developed nanoparticles capable of transporting the gene silencer and selectively delivering it into the target cells, enhancing molecular stability and ensuring prolonged therapeutic effects after administration.

The delivery system combines a biocompatible injectable hydrogel with PLGA nanoparticles, creating a percutaneously injectable and moldable medical device designed to fill bone defects and suitable for future craniofacial applications. The nanoparticles demonstrated high siRNA encapsulation efficiency; once released from the hydrogel, the siRNAs achieved up to 90% knockdown of the mutated gene and showed resistance to degradation. When 3D-printed, the system exhibited a controlled release profile, maintaining effective gene silencing for up to 20 days after administration. This multifunctional platform not only supports modulation of FGFR2 in disease but also holds translational promise as a customizable scaffold for delivering other bioactive compounds, thereby improving outcomes in pediatric cranial reconstructive surgery.

Towards Precision and Minimally Invasive Medicine

“These results are significant because they open the door to a precision-medicine and minimally invasive approach for the treatment of Crouzon syndrome and other craniosynostosis-related conditions,” explains Professor Lattanzi. Her research has received funding from several sources, including the Lazio Region, the Italian Ministry of Health (in collaboration with Professor Luca Massimi of the Pediatric Neurosurgery Unit), the French AFM-Téléthon Foundation, and the European Union.

Naturally, further studies in animal models followed by clinical trials to assess safety and efficacy in humans will be required—a process that typically takes several years of development and regulatory approval. If the preclinical phase proceeds without major obstacles, it is realistic to envisage that the first clinical studies could begin within the next five years.

Conclusion

In the long term, Professor Lattanzi concludes, this line of research represents a paradigm shift in the treatment of craniosynostosis: from repeated corrective surgery to targeted intervention on the molecular causes of the disease. The integration of genetics, nanotechnology, and 3D printing opens concrete prospects for personalized, less invasive therapies that could potentially be applied very early in life, with the aim of preventing malformations rather than merely mitigating their consequences. This work exemplifies how translational research can transform laboratory discoveries into innovative clinical solutions for rare diseases that currently lack effective therapeutic alternatives.