I am interested in the cellular mechanisms underlying growth and plasticity of neuronal connectivity. The gaseous messenger nitric oxide (NO) is one of the intercellular signals that regulate neural plasticity. In target cells, NO stimulates its main effector enzyme guanylyl cyclase to produce cGMP. Our developmental studies in insects implicate the NO/cGMP cascade as a permissive factor for axonal elongation, axonal regeneration, and enteric neuron migration. By employing small bioactive enzyme ligands in both gain-and loss-of-function experiments, we identified NO/cGMP signaling also as a positive regulator of migration in cultures of developing human brain cells. Since NO signaling regulates cell motility from insect to mammalian nervous systems, this transduction pathway may have evolutionary conserved functions. These findings have relevance for the development of therapeutic strategies to mobilize neuroblast migration and neurite growth after brain injury.
To reduce animal experiments, I have also initiated the establishment of predictive assays for developmental neurotoxicity testing, using cell cultures of human neurons and intact insect embryos. My other scientific hobby is looking at the cellular expression of neurotransmitter systems on a phylogenetic scale.
Bicker G (1998) NO news from insect brains. Trends Neurosci 21: 349-355.
Wildemann B and G Bicker (1999) Developmental expression of nitric oxide / cyclic GMP synthesizing cells in the nervous system of Drosophila melanogaster. J Neurobiol 38: 1-15.
Seidel C and G Bicker (2000) Nitric oxide and cyclic GMP influence axonogenesis of antennal pioneers. Development 127: 4541-4549.
Haase A and G Bicker (2003) Nitric oxide and cyclic nucleotides are regulators of neuronal migration in an insect embryo. Development 130: 3977-3987.
Bicker G (2005) Stop and Go with NO: nitric oxide as a regulator of cell motility in simple brains. BioEssays 27: 495-505.
Knipp S and G Bicker (2009) Regulation of enteric neuron migration by the gaseous messenger molecules CO and NO. Development 136: 85-93.
Tegenge MA and G Bicker (2009) Nitric oxide signal transduction facilitates the migration of human neuronal precursor (NT2) cells. J Neurochem 110: 1828-1841.
Roloff F, Scheiblich H, Dewitz C, Dempewolf S, Stern M, and G Bicker (2015) Enhanced
neurite outgrowth of human model (NT2) neurons by small-molecule inhibitors of
Rho/ROCK signaling. PLoS One. 10(2):e0118536.
Stemme T, Iliffe TM, and G Bicker G (2016) Olfactory pathways in Xibalbanus tulumensis: Remipedian hemiellipsoid body as homologue of hexapod mushroom body. Cell Tissue Res 363: 635-648.
Bode K, Bohn M, Reitmeier J, Betker P, Stern M, and G Bicker (2020) A locust embryo as predictive developmental neurotoxicity testing system for pioneer axon pathway formation. Arch Toxicol. 94:4099-4113.
I am a founding member of the Center for Systems Neuroscience (ZSN) Hannover