Caterina Missero, Ph.D.
Group Leader, Centre of Genetics Engineering
Ph.D. in Biology, University of Trieste (Trieste, Italy), 1989
Molecular basis of skin development and disease.
Our research focuses on the transcriptional mechanisms and genetic pathways required for normal skin development, in inherited and acquired skin diseases. Using primary keratinocytes derived from human and mouse skin, and mouse genetic models, we are investigating how epithelial cells in the skin establish unique programs of gene expression. More specifically, we are dissecting the molecular pathways controlled by the transcription factor p63 in epidermal cells. p63, a p53 family member, is essential for stratified epithelial development, and is responsible for the initiation of an epithelial stratification program during development and for maintenance of the proliferative potential of epidermal stem cells. Mutations in the p63 gene have been shown to cause inherited disorders characterized by ectodermal dysplasia and cleft lip and/or palate. While p63 mutations cause proliferative and differentiation defects in embryonic development, the p63 gene is amplified and/or overexpressed in squamous cell carcinomas, suggesting that .it may play a pro-oncogenic role
We previously identified a large set of p63 transcriptional targets by transcriptome analysis and ChIP-chip in mouse epidermal cells (Della Gatta et al., 2008). Among the signaling pathways involved in embryonic development, we demonstrated that p63 plays a key role in regulating keratinocyte differentiation at least in part through cross-regulation with Notch1 (Nguyen et al., 2006). In addition, we identified a previously uncovered role of p63 in controlling BMP signaling in the epidermis by direct regulation of Bmp7 and Smad7 (De Rosa et al., 2009). Canonical BMP/Smad signaling is essential downstream of p63 for negatively controlling expression of non-epidermal genes.
Pathogenetic mechanisms in AEC syndrome.
We recently generated a unique knock-in mouse model (p63+/L514F) for AEC syndrome, a rare autosomal dominant disorder characterized by cleft palate, skin defects, and ectodermal dysplasia, caused by missense mutations in the carboxyl terminal portion of p63 alpha isoform. Our mouse model faithfully recapitulates AEC syndrome (Ferone et al., 2012). Mutant mice die at birth with severe cleft palate, and ectodermal dysplasia. During development, p63+/L514F embryos display significant hypoplasia of the skin and palatal shelves, associated with decreased cell proliferation. The phenotype closely resembles the phenotype of Fgr2b null embryos. Accordingly, expression of Fgfr2b and its cognate gene Fgfr3b is reduced in mutant embryos and is directly controlled by p63. Reduced proliferation during embryogenesis leads to a reduce number of epidermal stem cells at birth, and consequent hypoplasia in the absence of proliferation defects. Skin fragility and skin erosions are hallmarks of AEC syndrome. We found that skin fragility is associated with microscopic blistering between the basal and suprabasal compartments of the epidermis and reduced desmosomal contacts in the AEC mouse. Expression of desmosomal cadherins and desmoplakin is strongly reduced in AEC mutant keratinocytes and in newborn epidermis. Importantly, a similar impairment in desmosome gene expression is observed in human keratinocytes isolated from AEC patients. We find that p63 controls these genes at the transcriptional level. Consistent with reduced desmosome function, AEC mutant keratinocytes have an impaired ability to withstand mechanical stress, which is alleviated by EGFR inhibitors known to stabilize desmosomes. Thus reduced mechanical strength resulting from p63 mutations can be alleviated pharmacologically by increasing desmosome adhesion with possible therapeutic implications.
Identification of self-renewal programs in epidermal stem cells.
The identity of epidermal stem cells has remained elusive. Several lines of evidence suggest that p63 is expressed at high levels in stem cells of various epithelia and is required for their long-term proliferative potential. We are prospectively identifying subpopulations of epidermal cells with long-term ability to regenerate epidermis by characterizing keratinocytes with elevated expression levels of p63 using an ad hoc mouse model, and an equivalent model in human keratinocytes. Surface markers associated with stemness will be identified by comparing the transcriptome of putative epidermal stem cells with that of their immediate progeny.
Characterization of p63 function in human epidermal neoplasia.
We are currently investigating the impact of p63 on cutaneous squamous cell carcinoma (SCC). We find that in SCC and in human primary keratinocytes, p63 knockdown causes cell cycle arrest independently of their p53 status. p63 positively controls cell cycle progression in a cell autonomous manner, at least in part through direct transcriptional repression of the microRNA-34 family (Antonini et al., 2010). p63 and its homolog p73 bind to the same consensus sequence of p53, share a subset of transcriptional targets, and physically interact with each other and with mutant p53. We are currently investigating the cross-talk between p63 and the other p53 family members in the context of cutaneous SCC development by inducible overexpression and knockdown experiments in human skin reconstitution assays and in appropriate mouse models.
Tissue-specific regulation of p63 expression.
p63 is one of the earliest markers of stratified epithelia during development, however the mechanisms controlling p63 expression are still poorly understood. Using a genomic sequence comparison approach across multiple vertebrate species, we isolated a highly conserved distal enhancer in the p63 locus that confers strong tissue-specific activity in transgenic mice (Antonini et al., 2006). Functional characterization of the enhancer has revealed an autoregulatory feedback loop in which the p63 protein directly binds and is an essential regulator of the enhancer. We are currently searching for other genomic elements in the p63 locus that contribute to regulate p63 gene expression. These studies will be crucial to identify major determinants of gene expression in stratified epithelia.
Antonini, D., Rossi, B., Han, R., Minichiello, A., Di Palma, T., Corrado, M., Banfi, S., Zannini, M., Brissette, J.L., Missero, C. (2006). An evolutionarily conserved long-range enhancer controls p63 expression through a positive autoregulatory loop. Mol. Cell. Biol., 2006;26 3308-3318.
Nguyen, B.-C., Lefort, K., Mandinova, A., Antonini, D., Devgan, V., Della Gatta, G., Koster, M.I., Zhang, Z., Wang, J., Tommasi di Vignano, A., Kitajewski, J., Chiorino, G., Roop, D.R., Missero*, C., Dotto*, G.P. (2006). Cross-regulation between Notch and p63 in keratinocyte commitment to differentiation. Genes Dev., 2006; 20 1028-1042. (*co-corresponding author and equal contribution).
Dentice, M., Luongo, C., Huang, S., Ambrosio, R., Elefante, A., Mirebeau-Prunier, D., Zavacki, A.M., Fenzi, G., Grachtchouk, M., Hutchin, M., Dlugosz, A.A., Bianco, A.C., Missero, C., Larsen, P.R., Salvatore, D. (2007). Sonic hedgehog-induced type 3 deiodinase blocks thyroid hormone action enhancing proliferation of normal and malignant keratinocytes. Proc Natl Acad Sci U S A,104(36):14466-71.
Roure, A., Rothbacher, U., Robin, F.,
Antonini, D., Dentice, M., Mahtani, P., De Rosa, L., Della Gatta, G., Mandinova, A., Salvatore, D., Stupka, E., Missero, C. (2008). Tprg, a gene predominantly expressed in skin, is a direct target of the transcription factor p63. J Invest Dermat, 128(7): 1676-1685.
Della Gatta, G., Bansal, M., Ambesi-Impiombato, A., Antonini, D., Missero*, C., di Bernardo*, D. (2008). Direct targets of the Trp63 transcription factor revealed by a combination of gene expression profiling and reverse engineering. Genome Research, 18(6): 939-48. (*co-corresponding author and equal contribution).
Fete, M., van Bokhoven, H., Clements, S., McKeon, F., Roop, D.R., Koster, M.I., Missero, C., Attardi, L.D., Lombillo, V.A., Ratovitski, E., Julapalli, M., Ruths, D., Sybert, V.P., Siegfried, E.C., Bree, A.F. (2009). Conference Report: International Research Symposium on Ankyloblepharon-Ectodermal Defects-Cleft Lip and/or Palate (AEC) Syndrome. The American Journal of Medical Genetics A, 149A(9):1885-93.
De Rosa, L., Antonini, D., Ferone, G., Russo, M.T., Yu, P.B., Han, R., Missero, C. (2009). p63 suppresses non-epidermal lineage markers in a BMP dependent-manner via repression of Smad7. J Biol Chem 284(44):30574-82.
Antonini, D., Russo, M.T., De Rosa, L., Garrese, M., Del Vecchio, L., Missero, C. (2010). Transcriptional repression of miR-34 family contributes to p63-mediated cell cycle progression in epidermal cells. J. Invest. Derm. 130(5):1249-57.
Rostagno, P., Wolchisky, Z., Vigano, AM,
Fessing, M.Y., Mardaryev, A.N., Gdula, M.R., Sharov, A.A., Sharova, T.Y., Rapisarda, V., Gordon, K.B., Smorodchenko, A.D., Poterlowicz, K., Ferone, G., Kohwi, Y., Missero, C., Kohwi-Shigematsu, T., and Botchkarev V.A. (2011). p63 Regulates Satb1 to Control Tissue-Specific Chromatin Remodeling during Development of the Epidermis. J.Cell.Biol. 194(6):825-39.
Rouleau M., Medawar A., Hamon L., Shivtiel S., Wolchinsky Z., Zhou H., De Rosa L., Candi E., de la Forest Divonne S., Mikkola M.L., van Bokhoven H., Missero C., Melino G., Pucéat M., Aberdam D. (2011). Tap63 is Important for Cardiac Differentiation of Embryonic Stem Cells and Heart Development. Stem Cells 29(11):1672-83.
Mitchell, M., O'Sullivan, J., Missero, C., Blair, E., Richardson, R.E., Antonini, D., Murray, J.C., Shanske, A.L., Schutte., B.C., Romano, R.A., Sinha, S., Bhaskar, S.S., Black, Graeme C., Dixon, J., Dixon, M.J. (2012). Exome sequence identifies RIPK4 as the Bartsocas Papas syndrome locus. AJHG, in press.
Ferone, G., Thomason, H., Antonini, D., De Rosa, L., Hu, B., Gemei, M., Zhou, H., Ambrosio, R., Rice, D., Acampora, D., van Bokhoven, H., Del Vecchio, L., Koster, M., Tadini, G., Spencer-Dene, B., Dixon, M., Dixon, J., Missero, C. (2012). Mutant p63 causes defective expansion of ectodermal progenitor cells and impaired FGF signaling in AEC syndrome. EMBO Mol. Med., 4 (3) 192-205.
Ferone, G. Mollo, M.R., Thomason, H.A., Antonini, D., Zhou, H., Ambrosio, R., De Rosa, L., Salvatore, D., Getsios, S, van Bokhoven, H., Dixon, J., Missero, C. (2012). p63 control of desmosome gene expression and adhesion is compromised in AEC syndrome. Hum. Mol. Gen., 2012 Oct 29.