Our vision is to contribute significant novel results and models in the field of calcium signalling with special emphasis of T-lymphocytes and cardiac myocytes. Moreover, in collaboration with chemists the development of novel lead compounds with pharmacological activity related to calcium signalling pathways is among the major research topics.

Projects

A. Cellular Ca2+ signaling: a major signal transduction pathway in cells

One of the fundamental processes in multicellular organisms is the exchange of information between individual cells. Evolution has invented hormones, mediators and cell-cell contacts to cope with this problem. Many of these extracellular signaling molecules are not membrane-permeant. Thus, to achieve, in the context of the multicellular organism, a meaningful cellular response, transmembrane signal transduction is required. A number of intracellular signal transduction pathways have been described; among them Ca2+ signaling is one of the most, if not the most, versatile pathway, since Ca2+ signaling is important in almost any cell type investigated.
Ca2+ signaling describes the fact that upon stimulation of receptors in the plasma membrane the free cytosolic and nucleoplasmic Ca2+ concentration ([Ca2+]i) undergoes changes. Usually, a global increase in [Ca2+]i is preceded by subcellular pacemaker Ca2+ signals. Both local and global Ca2+ signals often exhibit complex spatio-temporal patterns, e.g. oscillations and/or waves. [Ca2+]i is the resultant from at least four individual processes: Ca2+ release from intracellular stores and Ca2+ inflow from the extracellular space elevate [Ca2+]i, while Ca2+ extrusion by calcium pumps in both intracellular and plasma membranes and binding of Ca2+ ions to Ca2+ binding proteins reduces  [Ca2+]i. Although these general processes appear quite clear, the real situation in cells, even in one specific cell type, is much more complicated since many cell types express multiple Ca2+ channels in both plasma membrane and intracellular membranes, multiple Ca2+ pumps and multiple Ca2+ binding proteins. In many cases it is unclear why evolution invented that many different protein tools to enable cells to tune and fine-tune their [Ca2+]i. Nevertheless evolution may have had some good reasons to develop diversity and redundancy in this field; some thoughts on such potential reasons can be found in [da Silva & Guse 2000].

B. Biochemistry and pharmacology of the second messenger cyclic ADP-ribose  (cADPR)

Cyclic adenosine diphosphoribose (cADPR) was discovered as a Ca2+ mobilizing metabolite of nicotinamide adenine dinucleotide (NAD) by Lee and colleagues in 1987. The Ca2+ releasing activity of cADPR was first described in sea urchin egg homogenates. However, since 1987 cADPR has been shown to mobilize Ca2+ in many different organisms and cell types, ranging from protists to animal and plants. Collectively this work greatly facilitated acceptance of the concept of additional Ca2+ releasing messengers unrelated to InsP3 (reviewed in Guse 2002; Guse 2004a; Guse 2004b; Guse 2005).
In general, ligation of receptors in the plasma membrane by extracellular stimuli activates second messenger forming enzymes. Intracellular ADP-ribosyl cyclases (ADPRC), enzymes that covert NAD to cADPR, are still a matter of debate. It is clear that the ectoenzyme CD38, and to a lesser extent also CD157 (BST-1), synthesize cADPR as a byproduct. Another possibility for formation of cADPR is a cytosolic ADPRC; cytosolic ADPRC activities have been determined in some cell types and a cytosolic ADPRC has been purified to homogeneity from brain tissue. However, no such cytosolic ADPRC has been cloned as yet. Thus, the question of a cytosolic ADPRC awaits further clarification in the future.

Fig. 1 Model of the the cADPR/Ca2+ signaling system
Figure taken from Guse, FEBS J. 272, 4590-4597 (2005); copyright at The Federation of European Biochemistry Societies.

A general model of the cADPR/Ca2+ signaling system is depicted in Fig. 1. The data leading to this model are taken from several cell systems. Thus, in individual cell systems this model may apply only partially.

T-lymphocytes are one of the cellular systems most intensively studied regarding the role of cADPR. Most of the data published on T cells have been contributed by the Calcium Signalling group in collaboration with research groups located all over the world.

Stimulation of human Jurkat T cells by ligation of the T cell receptor/CD3 (TCR/CD3) complex stimulated a cytosolic ADPRC (Guse et al., 1999). A relatively slow increase combined with a sustained elevation of the intracellular concentration of cADPR was measured upon activation of ADPRC via the TCR/CD3 complex  (Guse et al., 1999). Most importantly, InsP3 showed a completely different time course with rapid accumulation within the first 2 or 3 minutes, but also with a fast decline of the InsP3 concentration within the first 15 to 20 minutes to a slightly elevated plateau level. Thus, it is likely that InsP3 plays a major role within the first phase of T cell Ca2+ signaling whereas cADPR is more important in the sustained Ca2+ signaling phase.
At least one of the molecular targets for cADPR appears to be the RyR expressed in T cells (Guse et al., 1995; Hohenegger et al., 1999; Guse et al., 1999). Using either type 3 RyR knock-down T cell clones (Schwarzmann et al., 2002) or pharmacological inhibition of cADPR by the membrane-permeant antagonist 7-deaza-8-Br-cADPR in wild-type Jurkat T cells (Guse et al., 1999), we showed recently that the sustained phase of TCR/CD3 mediated Ca2+ signaling depends on cADPR-mediated Ca2+ release via the type 3 ryanodine receptor. Using confocal Ca2+ imaging (Kunerth et al., 2003), it was demonstrated that the amplification of amplitude and spatial size of subcellular, local Ca2+ signals during the sustained Ca2+ signaling phase was greatly reduced in type 3 RyR knock-down T cell clones (Schwarzmann et al., 2002). In addition to this role of the cADPR/type 3 RyR/Ca2+ signaling system in the sustained phase of Ca2+ signaling, we have recently obtained evidence for a crucial role in the generation of early pacemaker Ca2+ signals in T cells, too (Kunerth et al., 2004). Recently, transient tyrosine phosphorylation of RyR was detected upon ligation of the TCR/CD3 complex. Moreover, it was shown that this phosphorylation of RyR enhanced the cADPR-mediated Ca2+ signal significantly (Guse et al., 2001). Together with the results of modulation of cADPR-mediated Ca2+ release by inorganic phosphate and Mg2+ ions (Guse et al., 1996), it appears that several factors add to the fine tuning of the cADPR/type 3 RyR/Ca2+ signaling system.
cADPR-mediated Ca2+ entry is another important issue of cADPR action in T cells (Guse et al., 1997a). As mentioned above, micronjection of cADPR resulted in rapid and long lasting Ca2+ signals in Jurkat T cells, which were dependent on the presence of extracellular Ca2+. Either or both of two potential mechanisms may be involved: (i) cADPR activates Ca2+ release from endogenous stores resulting in subsequent capacitative Ca2+ entry, or (ii), Ca2+ channels in the plasma membrane are directly activated by cADPR.

The medical importance of the cADPR/Ca2+ signaling system was demonstrated by antagonizing T cell activation by 7-deaza-8-Br-cADPR. This antagonist concentration-dependently blocked TCR/CD3 complex-mediated (i) sustained Ca2+ signaling in Jurkat T cells, (ii) expression of activation antigens MHC-II and CD25, and (iii) proliferation of peripheral human T cells (Guse et al., 1999). However, the TCR/CD3 complex is not the only Ca2+ mobilizing receptor connected to the cADPR/Ca2+signaling pathway in T cells. One component of the sustained Ca2+ signal obtained upon stimulation of T cells by laminin via a6ß1-integrin was blocked by the cADPR antagonist 7-deaza-8-Br-cADPR (Schöttelndreier et al., 2001). Taken together, these data suggest that the cADPR/Ca2+ signaling pathway of T cells represents a potential field for immunopharmacological intervention.

Special emphasis has been paid in the last years to the structure-activity relationship (SAR) of cADPR. In collaboration with chemical-synthetic laboratories in the UK (Barry V.L. Potter, University of Bath), in China (Li-he Zhang, Beijing University) and in France  (Francis Schuber, Strasbourg University) many synthetic agonists and a few antagonists have been developed (Guse et al., 1997b; Guse et al., 1999; Kunerth et al., 2004; Wagner et al., 2003a; Wagner et al., 2003b; Gu et al., 2004; Guse et al., 2005; Wagner et al., 2005; Kudoh et al., 2005). In 2005 a cADPR analogue was introduced with a much simplified structure; however, the molecule was still biologically active (Guse et al., 2005).

C. Biochemistry of the messenger nicotinic acid adenine dinucleotide phosphate (NAADP)

Like cADPR, nicotinic acid adenine dinucleotide phosphate (NAADP) was discovered by Lee and co-workers at the University of Minnesota. NAADP is the most potent Ca2+ mobilizing compound known so far. Although NAADP can be synthesized by CD38-type ADPRC/NADases by a base-exchange reaction, it is not generally accepted that this is the physiological way of NAADP formation (Fig. 2). The receptor for NAADP and the Ca2+ channel involved again are a matter of debate (Fig. 2): on the one hand evidence for the type 1 and 2 ryanodine receptor (RyR) has been presented, but on the other hand the pharmacology of NAADP-mediated Ca2+ release and NAADP binding in the sea urchin egg system, and the discovery of a NAADP-sensitive, lysosome-related Ca2+ pool in sea urchin eggs argue against involvment of RyR (Fig. 2).

Fig. 2 Model of the the NAADP/Ca2+ signaling system

In T-lymphocytes microinjection of NAADP dose-dependently stimulated intracellular Ca2+ signaling (Berg et al., 2000). Ca2+ mobilization was observed between 10 nM and 100 nM, while higher concentrations (1 and 10 mM) gradually reduced the initial Ca2+ peak, and a complete self-inactivation of Ca2+-signals was seen at 100 mM. Both inositol 1,4,5-trisphosphate and cADPR mediated Ca2+ signaling were efficiently inhibited by co-injection of a self-inactivating concentration of nicotinic acid adenine dinucleotide phosphate. Most importantly, microinjection of a self-inactivating concentration of NAADP completely abolished subsequent stimulation of Ca2+ signaling via the T cell receptor/CD3 complex indicating that a functional NAADP Ca2+ release system is essential for T-lymphocyte Ca2+ signaling (Berg et al., 2000).
Regarding the Ca2+ channel involved in the NAADP/Ca2+ signaling pathway, we have recently shown that upon microinjection of NAADP in T cells both early local and sustained global Ca2+ signals were abolished when RyR were blocked pharmacologically or when expression of RyR was down-modulated by anti-RyR antisense RNA (Langhorst et al., 2004; Dammermann &  Guse, 2005). We have also shown recently that microinjection of NAADP resulted in the activation of Ca2+ entry in T cells (Langhorst et al., 2004).

D. Adenosine diphosphoribose and TRPM2

Recently, it has been shown by different groups that the unspecific cation channel TRPM2 (transient receptor potential - melastatin-like, type 2) with selectivity for Ca2+ and Na+ is regulated by ADPR. ADPR can be formed by NADases or CD38-type ADPRC from NAD (Fig. 3) or formation can result from catabolism of cADPR or of poly-ADP-ribosyl-residues linked to proteins. TRPM2 is expressed mainly in cells of the immune system and in the CNS. We have recently established the first method to analyze endogenous ADPR by HPLC (Gasser & Guse, 2005).

Fig. 3 Model of the the ADPR/Ca2+ signaling system

E. Role of extracellular cADPR in Ca2+ signalling in fibroblasts
In collaboration with the Antonio De Flora and his group at Genova University (Italy) the role of cyclic ADP-ribose in the generation and amplification of subcellular and global Ca2+ signaling upon stimulation of P2Y purinergic receptors was studied in 3T3 fibroblasts (Bruzzone et al., 2003). We have used either 3T3 wt fibroblasts, 3T3 wt fibroblasts pre-loaded by incubation with extracellular cADPR, 3T3 wt fibroblasts microinjected with ryanodine, or 3T3 fibroblasts transfected with CD38. Both preincubation with cADPR and CD38 expression resulted in comparable intracellular amounts of cyclic ADP-ribose. P2Y receptor stimulation of CD38- cells yielded a small increase of [Ca2+]i and a much higher Ca2+ signal in CD38-transfectants, in cADPR-pre-loaded cells, or in cells microinjected with ryanodine. Single cell confocal Ca2+ imaging revealed that stimulation of ryanodine receptors by cADPR or ryanodine amplified localized pacemaker Ca2+ signals with properties resembling Ca2+ quarks and triggered the amplification and propagation of such localized signals from the plasma membrane toward the internal environment, thereby initiating a global Ca2+ wave (Bruzzone et al., 2003).

G. Ca2+ signalling in cardiac myocytes
In the context of the collaborative research group "Signalling mechanisms in the healthy and diseased heart" located at the University Medical Center Hamburg-Eppendorf we have started to analyze the novel Ca2+ signalling pathways described above in the heart. Recent data published in the Journal of Biological Chemistry indicate that the cADPR/Ca2+ signalling pathway is present in the heart (Guse et al., 2005).

Methods

A. Analysis of endogenous second messengers

One focus of the Calcium Signalling Group is to develop and apply methods to quantitatively determine second messengers in cells. The group has successfully introduced a 2-step HPLC method consisting of an SAX chromatography followed by an ion-pair RP step to analyze intracellular cADPR (da Silva et al., 1998; Guse et al., 1999).
Based on the method to quantify cADPR, we have recently developed an HPLC method for the determination of ADPR (Gasser & Guse, 2005). This method is in principle similar to the 2-step method described above, but the SAX-HPLC was replaced by an SAX solid phase extraction procedure using gravity fed columns.

B. Analysis of calcium signalling in cell suspensions

Analysis of calcium signalling in cell suspensions has been set up by the group since its beginning in late 1993. Cells are usually loaded by fura2/AM (Guse et al., 1993) and the free cytosolic and nuclear calcium concentration ([Ca2+]i) is determined by ratiometric fluorimetry (Guse et al., 1995). The advantage of this type of analysis is that results are already a representative average from many cells (> 106 cells in each measurement). The disadvantages are (i) low temporal resolution, (ii) inability to analyze single cells, and (iii) inability to analyze subcellular Ca2+ signals. However, for screening of compounds regarding interaction with cellular Ca2+ signalling, this type of analysis is well suited.
Often we need direct access to the receptors located on intracellular Ca2+ stores, e.g. the inositol 1,4,5-trisphosphate receptor or the RyR. This is the case, for example, if the activity of potential agonists or antagonists, which according to their structure are thought not to penetrate the plasma membrane, must be determined. Thus, protocols for the preparation of permeabilized Jurkat T cells have been established using saponin as detergent (Guse et al., 2002; Gu et al., 2004). In these permeabilized  cell preparations, the intracellular Ca2+ stores are loaded by SERCA pumps via addition of ATP and an ATP regenerating system (Guse et al., 2002; Gu et al., 2004). [Ca2+] is monitored in these experiments by fura2/free acid by ratiometric fluorimetry.

C. Analysis of calcium signalling in single cells by confocal methods

Calcium signalling can be divided into the global signals usually seen by conventional fluorimetry in cell suspensions and in local signals. To analyze the latter, high spatial and temporal resolution analysis on the single cell level is required. We have established confocal ratiometric calcium imaging methods based on a conventional rapid image acquisition setup and offline deconvolution of raw images  (Schwarzmann et al., 2002; Kunerth et al., 2003; Bruzzone et al., 2003; Kunerth et al., 2004; Gu et al., 2004; Kudoh et al., 2005; Dammermann & Guse, 2005). Both nearest-neighbour and no-neighbour algorithms are in use. The nearest-neighbour algorithm results in a good spatial resolution, but the temporal resolution is still not satisfactory. In contrast, the no-neighbour algorithm as a pure approximation method is fast (full frame ratio of a T cell in approx. 160 msec), but the degree of confocality is limited.
Currently, novel methods with better spatial and temporal resolution are under investigation.

To access the receptors located on intracellular Ca2+ stores, e.g. the inositol 1,4,5-trisphosphate receptor or the RyR directly, microinjection has been combined with confocal ratiometric calcium imaging. This allows to monitor the effects of calcium mobilizing messengers or drugs on the single cell level (Guse et al., 1997; Guse et al., 1999; Hohenegger et al., 1999; Berg et al., 2000; Kunerth et al., 2004; Langhorst et al., 2004; Dammermann & Guse 2005).

Publications

Berg I, Potter BV, Mayr GW, Guse AH. Nicotinic acid adenine dinucleotide phosphate (NAADP(+)) is an essential regulator of T-lymphocyte Ca(2+)-signaling. J Cell Biol. 2000 Aug 7;150(3):581-8

Bruzzone S, Kunerth S, Zocchi E, De Flora A, Guse AH. Spatio-temporal propagation of Ca2+ signals by cyclic ADP-ribose in 3T3 cells stimulated via purinergic P2Y receptors. J Cell Biol. 2003 Nov 24;163(4):837-45

Dammermann W, Guse AH. Functional ryanodine receptor expression is required for NAADP-mediated local Ca2+ signaling in T-lymphocytes. J Biol Chem. 2005 Jun 3;280(22):21394-9

da Silva CP, Potter BV, Mayr GW, Guse AH. Quantification of intracellular levels of cyclic ADP-ribose by high-performance liquid chromatography. J Chromatogr B Biomed Sci Appl. 1998 Apr 10;707(1-2):43-50

da Silva CP, Guse AH. Intracellular Ca(2+) release mechanisms: multiple pathways having multiple functions within the same cell type? Biochim Biophys Acta. 2000 Dec 20;1498(2-3):122-33

Gasser A, Guse AH. Determination of intracellular concentrations of the TRPM2 agonist ADP-ribose by reversed-phase HPLC. J Chromatogr B Analyt Technol Biomed Life Sci. 2005 Jul 25;821(2):181-7.

Gu X, Yang Z, Zhang L, Kunerth S, Fliegert R, Weber K, Guse AH, Zhang L. Synthesis and biological evaluation of novel membrane-permeant cyclic ADP-ribose mimics: N1-[(5''-O-phosphorylethoxy)methyl]-5'-O-phosphorylinosine 5',5''-cyclicpyrophosphate (cIDPRE) and 8-substituted derivatives. J Med Chem. 2004 Nov 4;47(23):5674-82

Guse AH, Roth E, Emmrich F. Intracellular Ca2+ pools in Jurkat T-lymphocytes. Biochem J. 1993 Apr 15;291 ( Pt 2):447-51.

Guse AH, da Silva CP, Emmrich F, Ashamu GA, Potter BV, Mayr GW. Characterization of cyclic adenosine diphosphate-ribose-induced Ca2+ release in T lymphocyte cell lines. J Immunol. 1995 Oct 1;155(7):3353-9.

Guse AH, Silva CP, Weber K, Ashamu GA, Potter BV, Mayr GW. Regulation of cADP-ribose-induced Ca2+ release by Mg2+ and inorganic phosphate. J Biol Chem. 1996 Sep 27;271(39):23946-53.

Guse AH, Berg I, da Silva CP, Potter BV, Mayr GW. Ca2+ entry induced by cyclic ADP-ribose in intact T-lymphocytes. J Biol Chem. 1997 Mar 28;272(13):8546-5

Guse AH, da Silva CP, Weber K, Armah CN, Ashamu GA, Schulze C, Potter BV, Mayr GW, Hilz H. 1-(5-phospho-beta-D-ribosyl)2'-phosphoadenosine 5'-phosphate cyclic anhydride induced Ca2+ release in human T-cell lines. Eur J Biochem. 1997b Apr 15;245(2):411-7.

Guse AH, da Silva CP, Berg I, Skapenko AL, Weber K, Heyer P, Hohenegger M, Ashamu GA, Schulze-Koops H, Potter BV, Mayr GW. Regulation of calcium signalling in T lymphocytes by the second messenger cyclic ADP-ribose. Nature. 1999 Mar 4;398(6722):70-3.

Guse AH, Tsygankov AY, Weber K, Mayr GW. Transient tyrosine phosphorylation of human ryanodine receptor upon T cell stimulation. J Biol Chem. 2001 Sep 14;276(37):34722-7

Guse AH. Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP): novel regulators of Ca2+-signaling and cell function. Curr Mol Med. 2002 May;2(3):273-82

Guse AH, Cakir-Kiefer C, Fukuoka M, Shuto S, Weber K, Bailey VC, Matsuda A, Mayr GW, Oppenheimer N, Schuber F, Potter BV. Novel hydrolysis-resistant analogues of cyclic ADP-ribose: modification of the "northern" ribose and calcium release activity. Biochemistry. 2002 May 28;41(21):6744-51

Guse AH. Regulation of calcium signaling by the second messenger cyclic adenosine diphosphoribose (cADPR). Curr Mol Med. 2004a May;4(3):239-48

Guse AH. Biochemistry, biology, and pharmacology of cyclic adenosine diphosphoribose (cADPR).Curr Med Chem. 2004b Apr;11(7):847-55
Guse AH, Second messenger function and the structure-activity relationship of cyclic adenosine diphosphoribose (cADPR). FEBS J. 2005 Sep;272(18):4590-7

Guse AH, Gu X, Zhang L, Weber K, Kramer E, Yang Z, Jin H, Li Q, Carrier L, Zhang L. A minimal structural analogue of cyclic ADP-ribose: synthesis and calcium release activity in mammalian cells.
J Biol Chem. 2005 Apr 22;280(16):15952-9

Hohenegger M, Berg I, Weigl L, Mayr GW, Potter BV, Guse AH. Pharmacological activation of the ryanodine receptor in Jurkat T-lymphocytes. Br J Pharmacol. 1999 Nov;128(6):1235-40

Kudoh T, Fukuoka M, Ichikawa S, Murayama T, Ogawa Y, Hashii M, Higashida H, Kunerth S, Weber K, Guse AH, Potter BV, Matsuda A, Shuto S. Synthesis of stable and cell-type selective analogues of cyclic ADP-ribose, a Ca(2+)-mobilizing second messenger. Structure--activity relationship of the N1-ribose moiety. J Am Chem Soc. 2005 Jun 22;127(24):8846-55

 Kunerth S, Mayr GW, Koch-Nolte F, Guse AH. Analysis of subcellular calcium signals in T-lymphocytes. Cell Signal. 2003 Aug;15(8):783-92

Kunerth S, Langhorst MF, Schwarzmann N, Gu X, Huang L, Yang Z, Zhang L, Mills SJ, Zhang LH, Potter BV, Guse AH. Amplification and propagation of pacemaker Ca2+ signals by cyclic ADP-ribose and the type 3 ryanodine receptor in T cells. J Cell Sci. 2004 Apr 15;117(Pt 10):2141-9

Langhorst MF, Schwarzmann N, Guse AH. Ca2+ release via ryanodine receptors and Ca2+ entry: major mechanisms in NAADP-mediated Ca2+ signaling in T-lymphocytes. Cell Signal. 2004 Nov;16(11):1283-9
 
Schottelndreier H, Potter BV, Mayr GW, Guse AH. Mechanisms involved in alpha6beta1-integrin-mediated Ca(2+) signalling. Cell Signal. 2001 Dec;13(12):895-9

Schwarzmann N, Kunerth S, Weber K, Mayr GW, Guse AH. Knock-down of the type 3 ryanodine receptor impairs sustained Ca2+ signaling via the T cell receptor/CD3 complex.J Biol Chem. 2002 Dec 27;277(52):50636-42

Wagner GK, Riley AM, Rosenberg HJ, Taylor CW, Guse AH, Potter BV. Analogues of cyclic adenosine 5'-diphosphate ribose and adenophostin A, nucleotides in cellular signal transduction. Nucleic Acids Res Suppl. 2003a;(3):1-2.

Wagner GK, Black S, Guse AH, Potter BV. First enzymatic synthesis of an N1-cyclised cADPR (cyclic-ADP ribose) analogue with a hypoxanthine partial structure: discovery of a membrane permeant cADPR agonist. Chem Commun (Camb). 2003 Aug 7;(15):1944-5

Wagner GK, Guse AH, Potter BV. Rapid synthetic route toward structurally modified derivatives of cyclic adenosine 5'-diphosphate ribose. J Org Chem. 2005 Jun 10;70(12):4810-9.

Extramural funding

Current funding of research work by
· DFG, including funding of TP4 of the DFG-Research Group 604: Signalling mechanisms in the healthy and diseased heart
· The Wellcome Trust (London)
· Gemeinnützige Hertie-Stiftung (Frankfurt)

Collaborations

Professor B.V.L. Potter, Dept. of Pharmacy & Pharmacology, University of Bath, UK
Professor Li-he Zhang, National Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
Professor T.F. Walseth, Dept. of Pharmacology, University of Minnesota, Minneapolis, USA
Dr. F. Lund, Trudeau Institute, Saranac Lake, NY, USA
Professor Antonio De Flora, Department of Experimental Medicine, Section of Biochemistry, and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
Priv.-Doz. Dr. Alexander Flügel, Max-Planck-Institute of Neurobiology, Martinsried
Professor Norman Oppenheimer, University of Calfornia, San Francisco, USA
Professor Francis Schuber, University Louis Pasteur and CNRS, Strasbourg, France
Professor Martin Hohenegger, Institut f. Pharmakologie, Universität Wien, Austria

Topics for MD theses (Themen für Med. Doktorarbeiten)

Themen auf Anfrage unter guse@uke.uni-hamburg.de