Journey into Pituitary Research: From Tumors to iPSC Models for Hypopituitarism

Maria Andrea Camilletti, PhD, gives insights into her personal journey into pituitary research on behalf of the Endocrine Society’s Early-Career Special Interest Group. Inspired by her family's scientific background, Camilletti always aspired to be a scientist, even before fully understanding what that entailed. Her mother, a biochemist, along with her grandfather and uncle—both agronomists and engineers—cultivated her curiosity about the natural world.

In 2007, she embarked on her biological sciences studies at the University of Buenos Aires (UBA), a prestigious public institution in Argentina. The dynamic environment of the university allowed her to learn from dedicated professors who were active in their fields, further inspiring her to delve into scientific research. During her studies, in 2011, Camilletti met Graciela Díaz, a prominent researcher focused on pituitary tumors. Under Diaz's mentorship at the Institute of Biology and Experimental Medicine (IBYME), Camilletti began to explore the complexities of neuroendocrinology, navigating the challenges of conducting research within a context marked by economic difficulties in Argentina.

Her fascination with the pituitary gland—a small yet powerful organ at the base of the brain, responsible for various key bodily functions including growth, metabolism, and reproduction—was deeply ignited during this time. As Camilletti states, “Immersing myself in bioinformatics and clinical genomics was both a challenging and rewarding experience. Working with patient data allowed me to exchange research results with esteemed experts and clinicians managing pituitary disorders across several hospitals in Argentina.”

Following her PhD, Camilletti reaffirmed her commitment to pituitary research by joining María Inés Pérez Millán's lab, a young and innovative researcher who had recently established her laboratory in Buenos Aires after a six-year postdoc at the University of Michigan. Her postdoctoral project was part of an ambitious initiative to create a multigene panel aimed at diagnosing congenital hypopituitarism (CH), a complex genetic disorder characterized by a deficiency of one or more pituitary hormones. The aim was to enhance molecular diagnostics of CH by identifying specific gene variants.

In the course of this research, more than 170 pediatric patients were screened for genetic alterations using a specially tailored sequencing panel, leading to a resolution of about 15.3% of sporadic cases. Camilletti notes, however, that many of the discovered variants were classified as variants of uncertain significance (VUS), necessitating further functional assays to better understand the pathogenic mechanisms involved.

To tackle the pressing need for reliable tools in exploring the roles of novel genes and genetic variants in CH, her research team shifted their focus toward induced pluripotent stem cell (iPSC) technology. This innovative cellular model has transformed research possibilities in medical science. After this transition, Camilletti was appointed as an independent researcher at the Institute of Neuroscience at FLENI, one of Argentina's top neurological institutes.

The iPSC technology, first developed by Shinya Yamanaka and Kazutoshi Takahashi in Japan in 2006, has revolutionized medicine. iPSCs are notable for their ability to self-renew and differentiate into virtually any type of specialized cell, including those in the endocrine system. Because they can be generated from a patient's own somatic cells, iPSCs circumvent several ethical issues associated with embryonic stem cells.

Camilletti’s current research emphasizes expanding knowledge about congenital hormonal deficiencies through the generation of iPSC-based in vitro models. Her team created an iPSC line from a patient with growth hormone (GH) deficiency and craniofacial malformations who harbored a novel heterozygous nonsense variant in the FOXA2 gene. While FOXA2 is poorly understood in the context of hormonal diseases, its specific role in pituitary development remains largely unexplored. This collaborative study involves specialists from both the Garrahan Hospital and the Faculty of Natural and Exact Sciences, representing an essential first step in disease modeling.

Next, the researchers aim to derive pituitary cells from the patient-derived iPSCs, comparing them with control iPSCs to assess the clinical impact of the FOXA2 variant. Camilletti hopes that their research efforts will facilitate better diagnoses, improve genetic counseling, and contribute to the development of effective treatments for affected patients and their families. As she states, “iPSC-based technologies have potential for modeling hormonal deficiencies and may eventually lead to cell transplantation therapies for hypopituitarism, paving the way for personalized medicine.”

This research is significant for enhancing local diagnostic capabilities for pituitary hormonal deficiencies and addressing the reasons behind how heterozygous FOXA2 variants can lead to CH in children. Furthermore, her laboratory is working on producing a FOXA2 knockout iPSC line using gene-editing technologies. They plan to apply genomics and proteomics methodologies to investigate the gene's role in pituitary differentiation and define its transcriptional regulatory framework during this process.

Camilletti thoroughly enjoys her time in the laboratory. Culturing iPSCs presents its own complexities, but successfully implementing techniques without contamination or errors is particularly gratifying. She remarks on the challenges inherent in working with iPSCs, noting that they are sensitive and must be cultured without antibiotics. One of her colleagues aptly describes the need to become a “ninja-culture technician” when managing these cells.

In addition to her research, Camilletti finds great satisfaction in mentoring new PhD students, where she thrives on discussing scientific data and sharing findings with broader audiences at various conferences. Ultimately, she aims for her research to benefit the community by improving diagnostic processes, genetic counseling, and the potential for future therapies for patients and their families.

Through her work, Camilletti is a testament to how modern research can be directed toward understanding and effectively treating complex hormonal deficiencies, thus offering hope for advances in personalized medical care and interventions.