Alessandra Bolino
Alessandra Bolino
affiliation: Università Vita-Salute San Raffaele
research area(s): Neuroscience, Cell Biology
Course: Cell and Molecular Biology
University/Istitution: Università Vita-Salute San Raffaele
1998-2000: Post-doctoral fellow, Univeristy of Oxford, Oxford, U.K.
1997: PhD in Human Genetics, Università di Torino
1991: Degree in Biological Sciences, Università di Genova

Professional experience
2007-to date: Head of the Human Inherited Neuropathies Unit, San Raffaele Scientific Institute, Milano
2006- to date: Associate Telethon Scientist, Dulbecco Telethon Institute
2001-2006: Assistant Telethon Scientist, Dulbecco Telethon Institute

Scientific Interest
- Human inherited neuropathies (Charcot-Marie-Tooth disease)
- Cellular and molecular biology of myelination
- Development of in vitro and in vivo models to study myelination
and the pathogenesis of inherited neuropathies
Myelin is a multilamellar membrane, which provides electrical insulation around the axon and participates to bidirectional communication with neurons and the extracellular environment. In glial cells, myelin biogenesis involves sorting and recruitment of selected lipids, proteins, and mRNAs to specific sub-domains, with a strong analogy to polarized transport in epithelial cells and neuronal synapses. However, the molecular basis for sorting and polarized transport in Schwann cells and oligodendrocytes are largely unknown.
The focus of our laboratory is to elucidate the molecular mechanisms that regulate membrane trafficking and homeostasis during myelin biogenesis and how defects of this process provoke human diseases.
1-Histopathological features may contribute to unravel the pathogenesis of rare CMT neuropathies
S. Benedetti, S. C. Previtali, S. Coviello, M. Scarlato, F. Cerri, E. Di Pierri, L. Piantoni, I. Spiga, R. Fazio, N. Riva, M. G. Natali Sora, P. Dacci, M. C. Malaguti, E. Munerati, L. M. E. Grimaldi, M.G. Marrosu, M. De Pellegrin, M. Ferrari, G. Comi, A. Quattrini, A. Bolino. Archives Neurology, 67: 1498-505 (2010).

2-Dlg1, Sec8, and Mtmr2 regulate membrane homeostasis in schwann cell myelination.
Bolis A, Coviello S, Visigalli I, Taveggia C, Bachi A, Chishti AH, Hanada T, Quattrini A, Previtali SC, Biffi A, Bolino A. Journal of Neuroscience 29: 8858-70 (2009).

3-The extracellular matrix composition affects regeneration and clinical outcome in axonal neuropathies
S.C. Previtali, M.C. Malaguti, N. Riv, M. Scarlato, P. Dacci, G. Dina, D. Triolo, E. Porrello, R. Fazio, G. Comi, A. Bolino, A. Quattrini.
Neurology, 71:322-331 (2008).

4-Loss of Mtmr2 phosphatase in Schwann cells but not in motor neurons causes CMT4B1 neuropathy with myelin outfoldings.
A. Bolis, S. Coviello, S. Bussini, G. Dina, C. Pardini, S.C. Previtali, M. Malaguti, P. Morana, U. Del Carro, M.L. Feltri, A. Quattrini, L. Wrabetz, A. Bolino. Journal of Neuroscience, 25: 8567-8577 (2005).

5-Disruption of Mtmr2 produces CMT4B1-like neuropathy with myelin outfolding and impaired spermatogenesis.
Bolino A*, Bolis A, Previtali SC, Dina G, Bussini S, Dati G, Amadio S, Del Carro U, Mruk DD, Feltri ML, Cheng CY, Quattrini A, Wrabetz L. Journal of Cell Biology, 167: 711-21 (2004).

6-Myotubularin-related 2 protein phosphatase and neurofilament light chain protein, both mutated in CMT neuropathies, interact in peripheral nerve
Previtali SC, Zerega B, Sherman DL, Brophy PJ, Dina G, King RHM, Salih MM, Feltri L, Quattrini A, Ravazzolo R, Wrabetz L, Monaco AP, Bolino A. Human Molecular Genetics, 12: 1713-1723 (2003).

7-Mutations in MTMR13, a new pseudo-phosphatase homologue of MTMR2 and Sbf1, are responsible for an autosomal recessive demyelinating form of Charcot-Marie-Tooth disease associated with juvenile-onset glaucoma.
Azzedine H,* Bolino A,* Taïeb T, Birouk N, Di Duca M, Bouhouche A, Benamou S, Mrabet A, Hammadouche T, Chkili T, Gouider R, Ravazzolo R, Brice A, Laporte J, LeGuern E. * Equally contributed. American Journal of Human Genetics, 72: 1141-1153 (2003).

8-Charcot-Marie-Tooth type 4 B is caused by mutations in the gene encoding the myotubularin related protein 2, MTMR2, on chromosome 11q22.
A. Bolino, M. Muglia, F.L. Conforti, E. LeGuern, A.M. Salih, D.M. Georgiou, R.K. Christodoulou, I. Hausmanowa-Petrusewicz, P. Mandich, A. Schenone, A. Gambardella, F. Bono, A. Quattrone, M. Devoto, A.P. Monaco. Nature Genetics, 25: 17-19 (2000).

Project Title:
The negative control of Schwann cell myelination
Loss of MTMR2/Mtmr2 (Myotubularin-related 2 protein) phospholipid phosphatase in both human and mouse causes autosomal recessive Charcot-Marie-Tooth type 4B1, a dys-myelinating neuropathy with myelin outfoldings, aberrant foldings of excessive membrane (Bolino et al. Nat Genet 2000). We provided evidence that MTMR2 controls membrane remodelling in Schwann cells by interacting with Dlg1/SAP97, a PDZ-containing scaffolding protein involved in cell polarity and protein trafficking, whose localization in Mtmr2-null mouse nerves is strongly altered (Bolino et al. J Cell Biol 2004; Bolis et al. J Neurosci 2009; Bolis et al. J Neurosci 2005).
To explore the role of Dlg1 in vivo, we generated a conditional null mouse in Schwann cells, using the Cre/loxP technology. In Dlg1-null mouse nerves we observed occasional myelin outfoldings and a significant increase of myelin thickness, which might result from activation of the NRG1-III (Neuregulin)-AKT pathway, one of the main signal promoting myelination. Interestingly, Dlg1 has been recently shown to interact also with the phospholipid phosphatase PTEN and that the DLG1/PTEN complex negatively regulates AKT activation and therefore myelination (Cotter et al., Science 2010). Accordingly, AKT phosphorylation is increased in Dlg1-null nerves.
We hypothesize that in myelin-forming Schwann cells two different complexes DLG1/MTMR2 and DLG1/PTEN can exist regulating longitudinal myelin growth (myelin outfoldings) and the number of myelin wraps (radial hypermyelination), respectively. This project will assess both in vitro and in vivo the role of DLG1, PTEN, and MTMR2 within the NRG1-III-AKT pathway by:
a) using biochemical and proteomic approaches to determine scaffold-phosphatase interactions;
b) establishing Schwann cell/DRG neuron co-cultures to explore the effect of these molecules on myelination;
c) generating and characterizing available conditional knock-out mice in Schwann cells for molecules of the AKT pathway.