Mechanisms Regulating Stem Cell Potency and Cell Fate Decisions
Development 2019 146: dev182170 doi: 10.1242/dev.182170
During development and lineage specification, pluripotent and adult stem cells generate the diverse arrays of specialized cells of the adult body.
Once a cell type is specified, the mechanisms that restrict and maintain cell fate are important in ensuring tissue integrity, and their dysregulation often results in disease, particularly cancer.
Our current research aims to understand the post-transcriptional & epigenetic mechanisms that govern stem cell potency and cell fate decisions, and determine how to exploit these mechanisms to develop new therapeutic strategies.
Towards this goal, our lab employs diverse approaches and tools including human and mouse embryonic stem cells, adult stem and progenitor cell cultures, 3D organoids, cellular reprogramming, transdifferentiation, in vivo mouse models, genome editing with CRISPR-Cas nucleases, and genome-wide techniques (e.g. scRNA-seq, ATAC-seq, ChIP-seq, CLIP-seq).
Mechanisms Governing Stem Cell Potency and Lineage Commitment
The capacity of cells to acquire new fates is central to the development of multicellular organisms and requires precise coordination of gene expression programs. A body of work has established the role of transcription and chromatin factors in defining and ultimately restricting cell identity. However, the post-transcriptional and post-translational mechanisms that govern cellular plasticity in development and tissue homeostasis remain largely unexplored.
Our current goal is to understand the post-transcriptional & post-translational mechanisms that govern stem cell self-renewal and differentiation across diverse developmental contexts.
Functional Role of P-bodies in Cell Fate Decisions
We recently uncovered that the RNA helicase DDX6 controls cellular plasticity by coordinating the cytoplasmatic storage of untranslated mRNAs in P-bodies. Interestingly, loss of DDX6 activity leads to the dissolution of P-bodies and the release of mRNAs encoding fate-instructive transcription and chromatin factors, thus altering chromatin landscapes. Our observations raise the intriguing possibility that P-bodies confer a “poised” state on stem cells, which facilitates cell fate decisions in a timely manner. However, the contribution of P-bodies to regulating cell fate in vivo remains unknown. Our aim is to dissect the functional role that P-body assembly by Ddx6 plays in the regulation of tissue homeostasis and lineage-specification.
Alternative Polyadenylation in Cancer
Our work has determined that the RNA binding protein Nudt21 is a crucial regulator of cellular reprogramming and progenitor cell differentiation. Mechanistically, Nudt21 stabilizes cell identity by directing alternative polyadenylation (APA), which generates distinct 3’ UTR isoforms for a given transcript by using different polyA sites. It has been estimated that ~70% of mammalian mRNAs are subject to APA, providing a potent strategy to regulate global gene expression patterns. One of the goals of our team is to dissect the molecular and functional roles that Nudt21 and APA play in the regulation of tumorigenesis.
JOIN OUR RESEARCH TEAM!
We are currently recruiting graduate students and postdocs
with a focus on stem cells, cancer, and RNA biology
Please submit CV and contact information for 3 references by email to Dr. Bruno Di Stefano
Bruno Di Stefano, Ph.D.
Assistant Professor in Molecular and Cellular Biology
Bruno received his BSc and MSc in Molecular Biology from the University of Pavia and the University School for Advanced Studies IUSS Pavia. He performed his graduate studies in the lab of Dr. Thomas Graf at the CRG. There his work focused on the mechanisms that control transcription factor-induced cell fate change. He developed the first rapid, ultra-efficient system to reprogram B cells into induced pluripotent stem cells. In 2016, he joined the lab of Dr. Konrad Hochedlinger as an EMBO long-term postdoctoral fellow at Harvard University. His postdoctoral work focused on the role of post-transcriptional mechanisms in cell fate programming.
Patrizia Pessina, Ph.D.
Patrizia received her MS in Biological Sciences and her PhD in Translational and Molecular Medicine from the University of Milano Bicocca. She completed her postdoctoral training in the Muñoz-Canoves Lab at the University of Pompeu Fabra where she studied muscle stem cells and fibrosis. From 2016 to 2020, Patrizia worked as Staff Scientist in the Carla Kim lab at Harvard Medical School studying stem cell function in lung fibrosis and aging. She joined the Di Stefano lab in October 2020.
Di Stefano B, Luo EC, Haggerty C, Aigner S, Charlton J, Brumbaugh J, Ji F, Jiménez IR, Clowers KJ, Huebner AJ, Clement K, Lipchina I, de Kort MAC, Anselmo A, Pulice J, Gerli MFM, Gu H, Gygi SP, Sadreyev RI, Meissner A, Yeo GW, Hochedlinger K. The RNA helicase DDX6 controls cellular plasticity by modulating P-body homeostasis. Cell Stem Cell 2019 Nov 7; 25 (5), 622-638.e13.
Cover of Cell Stem Cell 2019 Nov; Commented in Cell Stem Cell 2019 Nov 7; 25:589-1.
Francesconi M*, Di Stefano B*, Berenguer C, de Andrés-Aguayo L, Plana-Carmona M, Mendez-Lago M, Guillaumet-Adkins A, Rodriguez-Esteban G, Gut M, Gut IG, Heyn H, Lehner B, Graf T. Single cell RNA-seq identifies the origins of heterogeneity in efficient cell transdifferentiation and reprogramming. Elife 2019 Mar 12;8. pii: e41627.
Di Stefano B, Ueda M, Sabri S, Brumbaugh J, Huebner A, Sahakyan A, Clement K, Clowers KJ, Erickson AE, Shioda K, Gygi SP, Gu H, Shioda T, Meissner A, Takashima Y, Plath K, Hochedlinger K. Reduced MEK inhibition confers a growth advantage and preserves genomic stability in naïve human ES cells. Nat Methods 2018 Sep;15(9):732-740.
Brumbaugh J*, Di Stefano B*, Wang X, Borkent M, Forouzmand E, Clowers KJ, Ji F, Schwarz BA, Kalocsay M, Elledge SJ, Chen Y, Sadreyev RI, Gygi SP, Hu G, Shi Y, Hochedlinger K. Nudt21 Controls Cell Fate by Connecting Alternative Polyadenylation to Chromatin Signaling. Cell 2018 Jan 11; 172(1-2):106-120.e21.
Krijger PHL*, Di Stefano B*, de Wit E*, Limone F, Van Oevelen C, de Laat W, Graf T. Cell-of-Origin-specific 3D genome structure acquired during somatic cell reprogramming. Cell Stem Cell 2016 May 5;18(5):597-6.
Commented in Nat Rev Genet. 2016 May;17(5):253 and Cell Stem Cell. 2016 May 5;18(5):557-9.
Di Stefano B*,§, Collombet S*, Jakobsen JS*, Wierer M, Sardina JL, Lackner A, Stadhouders R, Segura-Morales C, Francesconi M, Limone F, Mann M, Porse B, Thieffry D, Graf T§. C/EBPa creates elite cells for iPSC reprogramming by upregulating Klf4 and increasing the levels of Lsd1 and Brd4. Nat Cell Biol 2016 Apr;18(4):371-81.
Cover of Nature Cell Biology 2016 Apr. and F1000 recommended.
Di Stefano B, Sardina JL, van Oevelen C, Collombet S, Kallin EM, Vicent GP, Lu J, Thieffry D, Beato M and Graf T. C/EBPa poises B cells for rapid reprogramming into induced pluripotent stem cells. Nature 2014, 506, 235–239.