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Caterina Missero, Ph.D. Group
Leader,
Centre of Genetics Engineering E-mail: missero@ceinge.unina.it Ph.D. in Biology, University of Trieste (Trieste, Italy), 1989 |
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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. Bibliography 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. |
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