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Beschreibung: Cardiac atrial natriuretic peptide (ANP) regulates arterial blood pressure, moderates cardiomyocyte growth, and stimulates angiogenesis and metabolism. ANP binds to the transmembrane guanylyl cyclase (GC) receptor, GC-A, to exert its diverse functions. This process involves a cGMP-dependent signaling pathway preventing pathological [Ca2+]i increases in myocytes. In chronic cardiac hypertrophy, however, ANP levels are markedly increased and GC-A/cGMP responses to ANP are blunted due to receptor desensitization. Here we show that, in this situation, ANP binding to GC-A stimulates a unique cGMP-independent signaling pathway in cardiac myocytes, resulting in pathologically elevated intracellular Ca2+ levels. This pathway involves the activation of Ca2+‐permeable transient receptor potential canonical 3/6 (TRPC3/C6) cation channels by GC-A, which forms a stable complex with TRPC3/C6 channels. Our results indicate that the resulting cation influx activates voltage-dependent L-type Ca2+ channels and ultimately increases myocyte Ca2+i levels. These observations reveal a dual role of the ANP/GC-A–signaling pathway in the regulation of cardiac myocyte Ca2+i homeostasis. Under physiological conditions, activation of a cGMP-dependent pathway moderates the Ca2+i-enhancing action of hypertrophic factors such as angiotensin II. By contrast, a cGMP-independent pathway predominates under pathophysiological conditions when GC-A is desensitized by high ANP levels. The concomitant rise in [Ca2+]i might increase the propensity to cardiac hypertrophy and arrhythmias.

Print ISSN: 0027-8424

Digitale ISSN: 1091-6490

Thema: Biologie , Medizin , Allgemeine Naturwissenschaft

Publiziert von National Academy of Sciences

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Immunoglobulin domain crossover as a generic approach for the production of bispecific IgG antibodies [Medical Sciences] (2011)

Schaefer, W., Regula, J. T., Bahner, M., Schanzer, J., Croasdale, R., Durr, H., Gassner, C., Georges, G., Kettenberger, H., Imhof–Jung, S., Schwaiger, M., Stubenrauch, K. G., Sustmann, C., Thomas, M., Scheuer, W., Klein, C.

National Academy of Sciences

In: PNAS - Proceedings of the National Academy of Sciences

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Publikationsdatum: 2011-07-06

Beschreibung: We describe a generic approach to assemble correctly two heavy and two light chains, derived from two existing antibodies, to form human bivalent bispecific IgG antibodies without use of artificial linkers. Based on the knobs-into-holes technology that enables heterodimerization of the heavy chains, correct association of the light chains and their cognate heavy chains is achieved by exchange of heavy-chain and light-chain domains within the antigen binding fragment (Fab) of one half of the bispecific antibody. This “crossover” retains the antigen-binding affinity but makes the two arms so different that light-chain mispairing can no longer occur. Applying the three possible “CrossMab” formats, we generated bispecific antibodies against angiopoietin-2 (Ang-2) and vascular endothelial growth factor A (VEGF-A) and show that they can be produced by standard techniques, exhibit stabilities comparable to natural antibodies, and bind both targets simultaneously with unaltered affinity. Because of its superior side-product profile, the CrossMabCH1-CL was selected for in vivo profiling and showed potent antiangiogenic and antitumoral activity.

Print ISSN: 0027-8424

Digitale ISSN: 1091-6490

Thema: Biologie , Medizin , Allgemeine Naturwissenschaft

Publiziert von National Academy of Sciences

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Induction of synaptic long-term potentiation after opioid withdrawal (2009)

R. Drdla ; M. Gassner ; E. Gingl ; [weitere]

American Association for the Advancement of Science (AAAS)

In: Science. 325(5937): 207-10. doi: 10.1126/science.1171759.

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Publikationsdatum: 2009-07-11

Beschreibung: mu-Opioid receptor (MOR) agonists represent the gold standard for the treatment of severe pain but may paradoxically also enhance pain sensitivity, that is, lead to opioid-induced hyperalgesia (OIH). We show that abrupt withdrawal from MOR agonists induces long-term potentiation (LTP) at the first synapse in pain pathways. Induction of opioid withdrawal LTP requires postsynaptic activation of heterotrimeric guanine nucleotide-binding proteins and N-methyl-d-aspartate receptors and a rise of postsynaptic calcium concentrations. In contrast, the acute depression by opioids is induced presynaptically at these synapses. Withdrawal LTP can be prevented by tapered withdrawal and shares pharmacology and signal transduction pathways with OIH. These findings provide a previously unrecognized target to selectively combat pro-nociceptive effects of opioids without compromising opioid analgesia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Drdla, Ruth -- Gassner, Matthias -- Gingl, Ewald -- Sandkuhler, Jurgen -- P 18129/Austrian Science Fund FWF/Austria -- New York, N.Y. -- Science. 2009 Jul 10;325(5937):207-10. doi: 10.1126/science.1171759.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19590003" target="_blank"〉PubMed〈/a〉

Schlagwort(e): Analgesics, Opioid/administration & dosage/*adverse effects/pharmacology ; Animals ; Calcium/metabolism ; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/administration & dosage/adverse ; effects/pharmacology ; Evoked Potentials ; GTP-Binding Proteins/metabolism ; Hyperalgesia/chemically induced ; *Long-Term Potentiation/drug effects ; Male ; Nerve Fibers, Unmyelinated/physiology ; Patch-Clamp Techniques ; Piperidines/administration & dosage/adverse effects/pharmacology ; Posterior Horn Cells/drug effects/physiology ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate/metabolism ; Receptors, Opioid, mu/*agonists ; Signal Transduction ; Substance Withdrawal Syndrome/*physiopathology ; Synapses/drug effects/*physiology

Print ISSN: 0036-8075

Digitale ISSN: 1095-9203

Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik

Publiziert von American Association for the Advancement of Science (AAAS)

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