Research Groups

Molecular Pathology

Research Interests and Description

Group Leader: Emanuele Buratti, PhD

Group Members

Research Interests

RNA-protein interactions. Defective RNA processing and neurodegeneration. Genetic disease caused by defective splicing.

Description of Research

The objectives of the Group are to investigate aberrant pre-mRNA processing defects that lead to disease in humans with special emphasis placed upon neurodegenration and metabolic diseases.
Regarding neurodegeneration, for many years the Group has been very active in investigating the biological properties of TDP-43, a nuclear factor involved in Amyotrophic Lateral Sclerosis and Frontotemporal Lobar Degeneration. With regard to splicing regulation, RNA metabolism has been demonstrated to play a major role in the correct maintenance of neuronal activity and survival. It should be considered, however, that in the eukaryotic nucleus many proteins are involved in regulating the correct processing, stability, and transport of RNA molecules. Like TDP-43, these proteins belong to the heterogeneous Ribonucleoproteins (hnRNPs) family. Most importantly, hnRNP proteins can form multimeric complexes, either with themselves or with different factors, and this can have a profound effect on their functional properties. This may be particularly important with regard to ALS and other related diseases, where alterations in the localization and solubility of several hnRNP factors have been shown to represent a possible cause of disease. Accordingly, we have started to study how the presence/absence of these proteins can contribute to influence TDP-43 functional properties. For example, we have recently gathered evidence that the interplay between the Drosophila homologues of TDP-43 and hnRNP A/B can be critical for neurodegeneration. At the moment we are investigating how TDP-43 regulated splicing events can be modulated by the presence of other hnRNP members, especially in the human context.
A second interest of the Group is in the field of metabolic diseases and, in particular, in the study of Glycogenosis Type 2 (aka Pompe Disease). Glycogenosis type 2 (G2) (OMIM 232300) is a lysosomal storage disorder due to mutations of the GAA gene, which causes lysosomal -glucosidase deficiency. Clinically, G2 has been classified in infantile and late-onset (LO) forms. Most LO patients shared the leaky splicing mutation c.-32-13T>G. Recently, we have demonstrated that the c.-32-13T>G mutation abrogates the binding of the splicing factor U2AF65 to the polypyrimidine tract of exon 2 and that several splicing factors affect exon 2 inclusion. We have shown that the only factor capable of acting in the c.-32-13 T>G context is the SR protein family member, SRSF4 (SRp75). A preliminary screening using small molecules described as able to affect splicing profiles, showed that resveratrol treatment resulted in a significant increase of SRSF4 levels within cells and this effect was accompanied by an increase in normal spliced GAA mRNA. As a result, GAAprotein content and activity was improved in fibroblasts from patients carrying the c-32-13T>G mutation. To bring these results closer to the development of a specific RNA-based therapy of G2, the following aims are being pursued:
- Better characterization of the splicing regulatory regions in GAA exon 2 to find suitable targets that could be exploited to improve exon 2 recognition in the presence of the c.-32-13T>G mutation. This will be achieved by targeting splicing silencer regions using antisense oligonucleotides or improving the recognition of exon 2 donor site by engineering mutated U1snRNP molecules that can better base-pair with this region.
- We have engineered an EGFP-based reporter system of GAA exon 2 splicing that can be adapted for use with a variety of Highthroughput experimental approaches to find small molecules and identify additional cellular factors capable of improving exon inclusion in the presence of the c.-32-13T>G mutation (see figure).

Recent Publications

Dardis, A., Zampieri, S.,  Canterini, S., Murrell, J., Newell, K., Stuani C., Ghetti, B., Fiorenza, M.T., Bembi, B., Buratti, E. 2016. Altered localization and functionality of TAR DNA Binding Protein 43 (TDP-43) in Niemann- Pick Disease Type C. Acta Neuropathologica Communications 4: 52. PubMed link

Gaweda-Walerych, K., Mohagheghi, F., Zekanowski, C., Buratti, E. 2016. Parkinson’s disease-related gene variants influence pre-mRNA splicing processes. Neurobiology of Aging, 2016, in press.

Buratti, E. 2015. Functional significance of TDP-43 mutations in disease. Advances in Genetics, 2015, 91: 1-53.  PubMed link

De Conti, L., Akinyi ,M.V., Mendoza-Maldonado, R., Romano, M. , Baralle, M. Buratti, E. 2015. TDP-43 affects splicing profiles and isoform production of genes involved in the apoptotic and mitotic cellular pathways. Nucleic Acids Research, 43: 8990-9005.  PubMed link

Mohagheghi, F., Prudencio, M., Stuani, C., Cook, C, Jansen-West, K., Dickson, D.W., Petrucelli, L., Buratti, E. 2015. TDP-43 functions within a network of hnRNP proteins to inhibit the production of a truncated human SORT1 receptor. Human Molecular Genetics, 25: 534-545.  PubMed link

Romano, V., Quadri, Z., Baralle, F.E., Buratti, E. 2015. The structural integrity of TDP-43 N-terminus is required for efficient aggregate entrapment and consequent loss of protein function. Prion, 9: 1-9.  PubMed link

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