Charlotte Kilstrup-Nielsen
Charlotte Kilstrup-Nielsen
affiliation: Università dell'Insubria
research area(s): Molecular Biology, Neuroscience
Course: Neurobiology
University/Istitution: Università dell'Insubria
1996: Degree in Biochemistry at University of Copenhagen, Denmark.
2003: PhD Cellular and Molecular Biology, Open University London, UK.
Professional Experiences
1997-1998: Post-graduate studies, San Raffaele Scientific Institute, Milan, Italy.
1998-2002: PhD training, Department of Biological and Technological Research, San Raffaele Scientific Institute, Milan, Italy.
2002-present: Assistant professor, Department of Structural and Functional Biology, University of Insubria.
Charlotte Kilstrup-Nielsen’s research activities are primarily focused on understanding the molecular causes of Rett syndrome (RTT), an X-linked neurological disorder that is the main cause of severe intellectual disabilities in females. Mutations in the epigenetic factor MeCP2 cause most cases of classic RTT whereas the kinase CDKL5 is mutated in some patients with the early-onset seizure variant. In order to understand the molecular mechanisms underlying RTT it is important to understand the specific roles of MeCP2 and CDKL5 in the nervous system and how their activities are regulated.
The activities of MeCP2 are regulated by its differential phosphorylation and a major interest of the laboratory is to understand the functional role of specific phosphorylation events. The laboratory has contributed to this field by identifying HIPK2 and CDKL5 as MeCP2 associated kinases and we are now investigating the role of these kinases for MeCP2 functions in vivo. Moreover, we have generated different phosphospecific MeCP2 antibodies and other reagents to study the role of specific MeCP2 phosphorylations.
Regarding CDKL5, only few data regarding its neuronal functions start accumulating. We have provided data indicating that MeCP2 and CDKL5 belong to a common molecular pathway and according to the current model, CDKL5 works upstream of MeCP2 and influences directly or indirectly its phosphorylation state and functions. In the absence of functional CDKL5, this modification of MeCP2 would be altered causing a subset of Rett symptoms; in addition, other as yet non-discovered targets of the kinase would also be deregulated leading to the specific phenotypes associated with CDKL5 mutations. The discovery of the other targets of CDKL5 in the brain would help identifying the molecular network belonging to the kinase and allow understanding the defects associated with mutations in the CDKL5 gene. By a yeast two hybdrid screen we have identified a number of novel CDKL5 interactors and currently we are characterizing the functional role of these interactions in primary neurons and electroporated embryonic mouse brains.
1. Mari F, Azimonti S, Bertani I, Bolognese F, Colombo E, Caselli R, Scala E, Longo I, Grosso S, Pescucci C, Ariani F, Hayek G, Balestri P, Bergo A, Badaracco G, Sapella M, Brocolli V, Renieri A, Kilstrup-Nielsen C, Landsberger N. (2005) CDKL5 belongs to the same molecular pathway of MeCP2 and it is responsible for the early-onset seizure variant of Rett syndrome. Hum Mol Genetics 14, 1935-1946.

2. Mari F, Kilstrup-Nielsen C, Cambi F, Speciale C, Mencarelli MA, Renieri A. (2005) Genetics and mechanisms of disease in Rett Syndrome. Drug Discovery Today. 2: 419-425.

3.Bertani I, Rusconi, Bolognese F, Forlani G, Conca B, De Monte L, Landsberger N, Kilstrup-Nielsen C. (2006). Functional consequences of mutations in CDKL5, an X-linked gene involved in infantile spasms and mental retardation. J.Biol.Chem. 281, 32048-32056.

4.Marchi M, Guarda A, Bergo A, Landsberger N, Kilstrup-Nielsen C, Ratto GM, Costa M. (2007) Spatio-temporal dynamics and localization of MeCP2 and pathological mutants in living cells. Epigenetics. 2, 187-197.

4.Rusconi L, Salvatoni L, Giudici L, Bertani I, Kilstrup-Nielsen C, Broccoli V, Landsberger N. (2008) CDKL5 expression is modulated during neuronal development and its subcellular distribution is tightly regulated by the C-terminal tail. J Biol Chem. 283, 30101-30111.

5.Bracaglia G, Conca B, Bergo A, Rusconi L, Zhou Z, Greenberg ME, Landsberger N, Soddu S, Kilstrup-Nielsen C. (2009) Methyl-CpG-binding protein 2 is phosphorylated by homeodomain-interacting protein kinase 2 and contributes to apoptosis. EMBO Rep. 10, 1327-1333.

6.Ricciardi S, Kilstrup-Nielsen C, Bienvenu T, Jacquette A, Landsberger N, Broccoli V. (2009) CDKL5 influences RNA splicing activity by its association to the nuclear speckle molecular machinery. Hum Mol Genet. 18, 4590-4602.

7.Forlani G, Giarda E, Ala U, Di Cunto F, Salani M, Tupler R, Kilstrup-Nielsen C, Landsberger N (2010) The MeCP2/YY1 interaction regulates ANT1 expression at 4q35: novel hints for Rett syndrome pathogenesis. Hum Mol Genet. 19, 3114-3123.

8. Williamson S, Giudici L, Kilstrup-Nielsen C, Gold W, Pelka G, Tam P, Grimm A, Prodi D, Landsberger N, Christodoulou J. (2011) A novel transcript of Cyclin-Dependent Kinase-like 5 (CDKL5) has alternative C-terminus and is the predominant transcript in brain. Hum Genetics [Epub ahead of print].

9. Rusconi L, Kilstrup-Nielsen C, Landsberger N. (2011) Extrasynaptic N-methyl-D-aspartate (NMDA) receptor stimulation induces cytoplasmic translocation of the CDKL5 kinase and its proteasomal degradation. J Biol Chem. 286, 36550-36558.

10. Kilstrup-Nielsen C, Rusconi L, La Montanara P, Ciceri D, Bergo A, Bedogni F, Landsberger N. (2012) What we know and would like to know about CDKL5 and its involvement in epileptic encephalopathy. Neural Plasticity. Epub 2012 Jun 17.

11. Ricciardi S, Ungaro F, Hambrock M, Rademacher N, Stefanelli G, Brambilla D, Sessa A, Magagnotti C, Bachi A, Kilstrup-Nielsen C, Sala C, Kalscheuer VM, Broccoli V. (2012) CDKL5 ensures excitatory synapse stability by reinforcing NGL1-PSD95 interaction in the post-synaptic compartment and is impaired in patient iPSC-derived neurons. Nature Cell Biology. In print.
Project Title:
Molecular pathologies and functional interactions of the X-linked MECP2 and CDKL5 genes
Rett syndrome (RTT) is a severe pediatric neurological disorder that, because of its incidence, represents the most common genetic cause of severe intellectual disability in girls worldwide. Several RTT variants have been described ranging from milder forms with a later age of onset to conditions with very early severe epileptic manifestations. Mutations in the transcriptional repressor MeCP2 (methyl CpG-binding protein 2) are found in the majority of patients with classic RTT whereas CDKL5 (cyclin-dependent kinase-like 5) is associated with the early-onset seizure variant. Clinical, genetic and biological data suggest a functional relationship between CDKL5 and MeCP2 leading to hypothesize that common biological networks are disrupted when either gene is mutated. To determine the degree of molecular overlap between MeCP2 and CDKL5, we have by a combined RNA-seq and bioinformatics approach identified a list of genes that are deregulated in hippocampal neurons devoid of either protein. The project is aimed at validating genes belonging to common molecular networks and performing functional studies to understand their relevance for RTT onset. Even though functional assays will be specifically tailored to the single genes, depletion or overexpression of the identified genes in primary neurons and in the neo-cortex of electroporated mouse embryos will permit verifying if their gain or loss of function mimics the loss of CDKL5 and/or MeCP2. Whenever possible, the student will also investigate if chemical compounds might be able to modulate the identified target genes.