Return to homepage
HPI seminars 2008 - 2009    06/02/2009



Hellenic Republic
Ministry of Development
General Secretariat
for Research and Technology
 
127, Vas. Sofias Avenue 11521,
Athens, Greece 
Τel: (+30) 210 6478 800
 Fax: (+30) 210 6423 498
 
 
Laboratory of Molecular Neurobiology & Immunology
 
Head of the lab:  Dr. Socrates Tzartos, 
Tel. +30-210-6478844, Fax. +30-210-6478842
Email:  tzartos@pasteur.grtzartos@upatras.gr

 
Introduction

Our laboratory is situated at the ground floor of building 6 (Biochemistry building) of HPI. Two additional floors are currently being constructed above the existing building for the expansion of our lab, funded exclusively by the lab’s budget.

Our main activities include:

a. The study of the structure and function of nicotinic acetylcholine receptors (AChRs) which are implicated in several severe neurological diseases.

b. The study of myasthenia gravis (MG), which is usually caused by anti-AChR autoantibodies, and the development of a specific therapy for this disease.

c. Investigation of the pathogenic role of another two membrane proteins, MuSK and aquaporin-4, in the autoimmune neurological diseases MG and neuromyelitis optica (NMO).

d. Very sensitive immunochemical diagnosis for three autoimmune neurological diseases (MG, NMO and LEMS).

e. Services to the scientific community (e.g. monoclonal antibodies, mass production of recombinant proteins by a high-tech bioreactor, protein crystallization by a robot, DLS, etc) and support to the Greek MG Association.

The expansion of our lab by the two additional floors will include, amongst others, a dedicated place (clean room) for the development of immunoadsorption columns under GMP standards necessary for the clinical trials for MG therapy, a crystallization room for structural studies, appropriate rooms for the further development of improved diagnostics for neurological diseases and for the research on these diseases. Additionally, the expanded laboratory will accommodate the administrative activities of the Hellenic Myasthenia Gravis Association (H-MGA).



Nicotinic Acetylcholine Receptors (AChRs)

Our laboratory is mainly studying the structure of the human nicotinic acetylcholine receptors (AChR) and their role in several related neurological diseases. AChRs are a family of membrane proteins located in a number of synapses, either in the nervous system (central and peripheral) or in the neuromuscular junctions mediating neuromuscular transmission. AChRs are involved in several diseases, such as myasthenia gravis (MG) and myasthenic syndromes (muscle type AChRs), Alzheimer’s disease, Parkinson’s disease and schizophrenia as well as the addiction to smoking (neuronal AChRs). Their importance in physiology and pathology and the fact that they have been extensively studied renders the AChRs as model neurotransmitter receptor molecules.

Muscle AChR and MG. The skeletal muscle AChR, consisting of 5 subunits (αβγαδ or αβεαδ), is fundamental for the neuromuscular transmission. In MG, patients produce autoantibodies, which destroy the AChRs at the neuromuscular junctions, resulting in muscular weakness and fatigability. As the number of diagnosed patients increases, there is a need for the development of improved and specific therapeutic approaches for MG. Our studies involve mainly the thorough understanding of the antigenic structure of muscle AChR, the pathogenic mechanisms in MG, efforts to develop novel immunospecific therapeutic approaches and the better diagnosis of the disease. The therapeutic approach which is being developed by our lab focuses on the use of recombinant AChR fragments with correct conformation as immunoadsorbents of patients’ antibodies.

Neuronal nicotinic AChRs. Neuronal AChRs are very heterogeneous. They are also pentameric proteins, each formed by 1-4 kinds of homologous subunits chosen from a pool of 9 alpha (α2-10) and 3 beta (β2-4) subunits. We have initiated studies on some of the most important subunits for understanding their structure, function and involvement in pathology. To this aim we express the extracellular domains of human neuronal subunits in eukaryotic expression systems, we produce monoclonal antibodies against them and we study their structural and biological properties.

 

MuSK and myasthenia gravis

About 5% of the MG patients have antibodies to the muscle specific kinase MuSK, rather than to the AChR. MuSK is necessary for AChR clustering and function. We are studying the pathogenic role of the anti-MuSK antibodies and we aim towards the development of a similar with the above specific therapy for these patients

Aquaporin-4 and neuromyelitis optica (NMO). Recently we became involved in the study of an additional autoimmune neurological disease, neuromyelitis optica (NMO), which is related to multiple sclerosis. NMO is believed to be caused by autoantibodies against aquaporin-4, the most abundant water channel protein in the brain, expressed from glia cells. We aim to elucidate the pathogenic role of the autoantibodies directed against this protein.

Diagnosis of three neurological diseases.

a. Myasthenia Gravis (detection of antibodies to AChR, MuSK and titin) Our laboratory is the main diagnostic centre for myasthenia gravis (anti-AChR and anti-MuSK antibody assays) in Greece. About 3000 seropositive patients have been diagnosed since 1983. Recently, we have also introduced the detection of antibodies against the muscle protein titin; the presence of such antibodies (in anti-AChR-positive myasthenia) is an indication for possible presence of thymoma.

b. Neuromyelitis optica (NMO) or Davic’s disease (since 2009). Detection of autoantibodies against aquaporin-4 with a very sensitive radio-immunoassay, which has been developed by our lab.

c. Lambert-Eaton myasthenic syndrome (LEMS) (since 2009). Detection of autoantibodies against calcium channels.

Hellenic Myasthenia Gravis Association (H-MGA)

In addition, through communication with patients, we have recently (September, 2008) helped in the creation of the Hellenic Myasthenia Gravis Association (www.myasthenia.gr, info. Mrs E. Tzartou, tel. 210-6478844). The association is based at the Pasteur Institute and aims at the assistance of the patients in every level.

Services to the scientific community

We provide many monoclonal antibodies against AChR subunits and several AChR subunit domains as well as MuSK and aquaporin-4 proteins, and we also provide the expertise for the production of monoclonal antibodies to important proteins, the mass production of recombinant proteins by a high-tech bioreactor, protein crystallization by a robotic system, DLS, etc.

PATENTS

Tzartos, S.J., Psaridi-Linardaki, L., Kostelidou, K. and Mamalaki, A., (2003). Production of recombinant fragments of muscle acetylcholine receptor and their use for ex vivo immunoadsorption of anti-ACh receptor antibodies from myasthenic patients. Greek (Νο. 1004240/2003) and European (1509605/2009) patent.


http://www.b2b12.com/