CHRISTOPH WINKLER

CHRISTOPH WINKLER

Associate Professor and Assistant Head of Department

Contact Information:

Department of Biological Sciences
National University of Singapore
14 Science Drive 4
Block S1A, Level 6
Singapore 117543

Lab webpage: Winkler’s Lab

6516 7376
6779 2486
dbswcw@nus.edu.sg

Curriculum vitae


Research Areas

Developmental Biology, Neurogenetics, Molecular Cell Biology

Research Interests

1. Photoreceptor degeneration in a zebrafish model for Retinitis pigmentosa

Retinitis pigmentosa (RP) is an inherited eye disease characterized by progressive photoreceptor degeneration. 12% of patients suffering from RP carry mutations in the RNA splicing factors PRPF3, PRPF8 and PRPF31. How mutations in these ubiquitous splicing factors selectively cause degeneration of photoreceptors remains unknown. We have established a zebrafish model to address this problem. This model allows a unique combination of powerful genetics and dynamic bioimaging in vivo. Using advanced confocal microscopy, we were the first to visualize the effects of distinct PRPF31 mutations on photoreceptor degeneration in an in vivo setting. Furthermore, we were the first to identify aberrantly spliced mRNA targets in this model, yielding important new insight into the mechanism of splice factor induced neuron degeneration.

2. In vivo imaging of osteoblast-osteoclast interaction in a medaka model for osteoporosis

We are interested in the cellular mechanisms that control bone homeostasis. Fish, such as medaka, have bone cells very similar to humans. Also, the genetic networks regulating formation of bone-forming osteoblasts and bone-resorbing osteoclasts are highly conserved. We have established several transgenic medaka lines that express fluorescent reporters in bone cells at distinct stages of differentiation, or express RANKL, an osteoclast-inducing factor, under control of a heatshock promoter. Upon heatshock, RANKL induces the formation and activation of ectopic osteoclasts. This results in degradation of bone matrix in a manner very similar to the situation in human osteoporosis patients. This unique in vivo model allows visualization of osteoblast/osteoclast interaction in an intact living animal during bone degradation as well as regeneration.

3. Neurogenesis and neural differentiation in the embryonic spinal cord

Our nervous system consists of billions of neurons that interconnect in a very precise manner to allow proper function of the nervous system. To achieve this extraordinary complexity, neurons need to be born at exactly defined time points and positions in the developing embryo and make specific interconnections. Using the zebrafish model, we analyze how growth factors (Midkines), their receptors (Alk, RPTPs) and a class of transcription factors (the Dmrt family) control timing and position of neuron birth and differentiation in brain and spinal cord.

4. FRET-based Ca2+ sensors to visualize neuron-glia interaction during synapse establishment in a zebrafish model for Spinal Muscular Atrophy

We have generated transgenic zebrafish lines that express a FRET-based ratiometric Ca2+ sensor in motoneurons and surrounding glia cells. These lines allow imaging of Ca2+ influx and thus activaty of neurons and glia during synapse establishment and maintenance in intact embryos. Ca2+ influx is analyzed during normal development and in our zebrafish model for Spinal Muscular Atrophy (SMA), a common neurodegenerative disorder characterized by progressive motoneuron degeneration with unclear etiology.

 

Selected Publications 2014-2020

  1. Phan, Q.T., Tan, W.H., Liu, R.R., Sundaram, S., Buettner, A., Kneitz, S., Cheong, B., Vyas, H., Mathavan, S., Schartl, M., Winkler, C. (2020). Cxcl9l and Cxcr3.2 regulate recruitment of osteoclast progenitors to bone matrix in a medaka osteoporosis model. Proc Natl Acad Sci USA. In Press.

  2. Imangali N, Phan QT, Mahady G, Winkler C. (2020). The dietary anthocyanin delphinidin prevents bone resorption by inhibiting Rankl-induced differentiation of osteoclasts in a medaka (Oryzias latipes) model of osteoporosis. J Fish Biol. In press.

  3. Pham, C.V., Pham, T.T., Lai, T.T., Trinh, D.C., Nguyen, H.V.M., Ha, T.T.M., Phuong, T.T., Tran, L.D., Winkler, C., To, T.T. (2020). Icariin reduces bone loss in a Rankl-induced transgenic medaka (Oryzias latipes) model for osteoporosis. J Fish Biol. In press.

  4. Lleras-Forero, L., Winkler, C. and Schulte-Merker, S. (2020). Zebrafish and medaka as models for biomedical research of bone diseases. Developmental Biology 457, 191-205.

  5. Dasyani, M., Tan, W.H., Sundaram, S., Imangali, N., Centanin, L., Wittbrodt, J., and Winkler, C. (2019). Lineage tracing of col10a1 cells identifies distinct progenitor populations for osteoblasts and joint cells in the regenerating fin of medaka (Oryzias latipes). Developmental Biology 455, 85-99.

  6. Foo, Y.Y., Pant, S., Tay, S., Imangali, N, Chen, N., Winkler, C., Yap, C.H. (2019). 4D modelling of fluid mechanics in the zebrafish embryonic heart. Biomechanics and Modeling in Mechanobiology 19, 221-232.

  7. Buettner, A., Sundaram, S., Vyas, H., Yu, T., Mathavan, S., and Winkler, C. (2018). Fluorescence-activated cell sorting (FACS) of osteoblasts and osteoclasts for RNA sequencing in a medaka (Oryzias latipes) osteoporosis model. Journal of Applied Ichthyology 34, 481-488.

  8. Yu, T., Graf, M., Renn, J., Schartl, M., Larionova, D., Huysseune, A., Witten, P.E., Winkler, C. (2017). A vertebrate specific and essential role for sp7/osterix in osteogenesis revealed by gene knock-out in the teleost medaka. Development 144:265-271.

  9. Witten, P.E., Harris, M.P., Huysseune, A., Winkler C. (2017). Small Teleost Fish Provide New Insights into Human Skeletal Diseases. Methods Cell Biol 138, 321-346.

  10. Tan, W.H., Witten, P.E., Winkler C., Au, D.W.T., Huysseune, A. (2017). Telomerase expression in medaka (Oryzias melastigma) pharyngeal teeth. Journal of Dental Research 96, 678-684.

  11. Watson, A.T.D., Planchart, A., Mattingly, C.J., Winkler, C., Reif, D.M., Kullman, S.W. (2017). Embryonic exposure to TCDD impacts osteogenesis of the axial skeleton in Japanese medaka, Oryzias latipes. Toxicological Sciences 155, 485-496.

  12. Yu, T., and Winkler, C. (2017). Drug treatment and in vivo imaging of osteoblast-osteoclast interactions in a medaka fish osteoporosis model. Journal of Visualized Experiments 1:119.

  13. Spiró, Z., Koh, A., Tay, S., See, K., Winkler, C. (2016). Transcriptional enhancement of Smn levels in motoneurons is crucial for proper axon morphology in zebrafish. Scientific Reports 6:27470.

  14. Yu, T., Buettner, A., To, T.T., Witten, P.E., Huysseune, A., Winkler, C. (2016). Live imaging of osteoclast inhibition by bisphosphonates in a medaka osteoporosis model. Disease Models & Mechanisms 9(2), 155-163.

  15. To, T.T., Witten, P.E., Huysseune, A., Winkler, C. (2015). An adult osteopetrosis model in medaka reveals importance of osteoclast function for bone remodeling in teleost fish. Comp Biochem Physiol C Toxicol Pharmacol 178:68-75.

  16. Willems, B., Tao, S., Yu, T., Huysseune, A., Witten, P.E., Winkler, C. (2015). The Wnt co-receptor Lrp5 is required for cranial neural crest cell migration in zebrafish. PLoS ONE  10(6):e0131768.

  17. Quach, H.N.B., Tao, S., Vrljicak, P., Joshi, A., Ruan, H., Sukumaran, R., Varshney, G., LaFave, M., The Ds screen team, Burgess, S., Winkler, C., Emelyanov, A., Parinov, S., Sampath, K. (2015). A Multifunctional Mutagenesis System for Analysis of Gene Function in Zebrafish. G3: Genes, Genomes, Genetics 5(6), 1283-1299.

  18. Graf, M., Teo Qi-Wen, E.R., Sarusie, M.V., Rajaei, F., Winkler, C. (2015). Dmrt5 controls corticotrope and gonadotrope differentiation in the zebrafish pituitary. Mol Endocrinol 29, 187-99.

  19. Linder, B., Hirmer, A., Gal, A., Rüther, K., Bolz, H.J., Meitinger, T., Winkler, C., Laggerbauer, B., Fischer, U. (2014). Identification of a PRPF4 loss-of-function variant that abrogates U4/U6.U5 tri-snRNP integration and is associated with Retinitis pigmentosa. PLoS ONE 9(11): e111754.

  20. Renn, J., Winkler C. (2014). Osterix/Sp7 regulates biomineralization of otoliths and bone in medaka (Oryzias latipes). Matrix Biology 34, 193-204.

  21. See, K., Yadav, P., Giegerich, M., Cheong, P.S., Graf, M., Vyas, H., Lee, S.G.P, Mathavan, S., Fischer, U., Sendtner, M., Winkler, C. (2014). SMN-deficiency alters Nrxn2 expression and splicing in zebrafish and mouse models of spinal muscular atrophy. Human Molecular Genetics 23, 1754-1770.

  22. Winkler, C. and Yao, S. (2014). The midkine family of growth factors: Diverse roles in nervous system formation and maintenance. British Journal of Pharmacology 171, 905-912.