Reader in Comparative Developmental Neurobiology
Clare Baker is accepting applications for PhD students.
Neurogenic placodes and the neural crest: development and evolution of the vertebrate peripheral sensory nervous system
Neurogenic placodes and the neural crest are two distinct embryonic cell populations that are crucial for the development of the vertebrate head. Together, they give rise to the whole peripheral nervous system, i.e., all the sensory receptor cells, neurons (nerve cells) and glial cells (nerve-support cells) located outside the brain and spinal cord. Neural crest cells also build much of the craniofacial skeleton.
Neurogenic placodes (paired patches of thickened surface ectoderm in the embryonic head) give rise to the paired peripheral sense organs: the olfactory placodes form the olfactory receptor neurons in the nose that detect smells; the otic placodes form the inner ears, in which fluid movement (due to sound waves or head motion) stimulates mechanosensory hair cells, giving us our senses of hearing and balance; and a series of lateral line placodes forms the lateral line system of fish and aquatic-stage amphibians, in which mechanosensory hair cells (very like those in the inner ear), distributed in lines over the head and flank, detect local water movement for e.g. prey/predator detection and schooling behaviour. Neurogenic placodes also form the hormone-producing cells of the anterior pituitary gland, the eye lenses, and most of the peripheral sensory neurons of the head, collected in discrete cranial sensory ganglia.
Neural crest cells migrate out of the developing brain and spinal cord: they give rise to all the other neurons and all glial cells of the peripheral nervous system, plus a wide variety of other cell types including pigment cells, most of the cartilages and bones of the face and skull, and the dentine-producing cells of teeth.
Development of olfactory ensheathing glia
Using grafting techniques in chicken embryos and genetic lineage-tracing in mice, we discovered that olfactory ensheathing cells (OECs, which ensheath and protect olfactory nerve fibres) are derived from the neural crest, like all other peripheral glial cells, and not from the olfactory placodes as previously thought (Barraud et al., 2010, Proc. Natl. Acad. Sci. USA). Excitingly, OECs can promote nerve repair when transplanted into the damaged spinal cord, but it has proved difficult to isolate them in large enough numbers from the nose for effective therapy. Neural crest stem cells persist in adult skin and hair follicles, and it is possible to isolate these stem cells and grow them in the lab. The next step is to work out how to turn these stem cells into OECs: to do this, we need to investigate how this process happens normally in the developing embryo. We are currently investigating this question, as well as the role of OECs during the embryonic development of the olfactory system.
Development and evolution of electroreceptors
Land vertebrates, as well as frogs and most modern bony fish, have lost one of the most ancient vertebrate senses, the ability to detect weak electric fields in water, used for finding prey and for orientation. Electroreceptors are modified hair cells, distributed in fields of "ampullary organs" on either side of the lateral lines of mechanosensory hair cells. They are found in all major aquatic vertebrate groups, including jawless fish (lampreys), cartilaginous fish (sharks, rays), primitive bony fish (e.g. sturgeon, paddlefish), and even some amphibians (salamanders). Although the ancestors of teleosts (modern bony fish) lost electroreceptors, so that most of these fish cannot detect electric fields, electroreceptors seem to have been independently "re-invented" at least twice in two different groupsof teleosts, including catfish and "electric fish". (For more information on vertebrate electroreception, see Map Of Life). Very little is known about electroreceptor development. We are investigating the embryological origins of electroreceptors, and the genes underlying their formation, in a wide range of vertebrate groups including skate, paddlefish, salamander and catfish.
Development and evolution of the carotid body
The carotid bodies are small glands located near the carotid artery, one on either side of the neck, which originate embryonically from the neural crest. When blood oxygen levels drop, such as during exercise or at high altitudes, the hypoxia-sensitive 'glomus cells' of the carotid body signal to the brain to cause hyperventilation and increase the heart rate, so that more oxygen is delivered to the body's cells. We are investigating the development and evolution of carotid body glomus cells.
Current research team
Martin Minařík (BBSRC-funded Research Associate)
Surangi Perera (Wellcome Trust-funded PhD student)
Christine Hirschberger (BBSRC-funded rotating PhD student)
Oliver Stubbs (Part II PDN undergraduate project student)
Igor Adameyko, Medical University of Vienna, Austria and Karolinska Institutet, Stockholm, Sweden
Marianne Bronner, California Institute of Technology, Pasadena, CA, USA
Andrew Gillis, Department of Zoology, University of Cambridge
Frédéric Relaix, INSERM, Paris, France
Lukas Sommer, University of Zurich, Switzerland
Michelle Southard-Smith, Vanderbilt University, TN, USA
Michael Wegner, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
Harold Zakon, University of Texas at Austin, TX, USA
Part IA MVST Functional Architecture of the Body
Part IB MVST Head & Neck Anatomy
Part IB MVST Neurobiology and Human Behaviour
Part II PDN module N1 Developmental Neurobiology
Hockman D, Burns A, Schlosser G, Gates KP, Jevans B, Mongera A, Fisher S, Unlu G, Knapik EW, Kaufman CK, Mosimann C, Zon LI, Lancman JJ, Dong PDS, Lickert H, Tucker AS, Baker CVH (2017) Evolution of the hypoxia-sensitive cells involved in amniote respiratory reflexes. eLife, in press, doi 10.7554/eLife.21231
Modrell MS, Lyne M, Carr AR, Zakon HH, Buckley D, Campbell AS, Davis MC, Micklem G, Baker CVH (2017) Insights into electrosensory organ development, physiology and evolution from a lateral line-enriched transcriptome. eLife, in press, doi 10.7554/eLife.24197
Miller SR, Perera SN, Baker CVH (2017) Constitutively active Notch1 converts cranial neural crest-derived frontonasal mesenchyme and glia to perivascular cells. Biol. Open 6, 317-25
Miller SR, Perera SN, Benito C, Stott SRW, Baker CVH (2016) Evidence for a Notch1-mediated transition during olfactory ensheathing cell development. J. Anat. 229, 369-383
Piotrowski T, Baker CVH (2014) The development of lateral line placodes: Taking a broader view, Dev. Biol. 389, 68-81
Modrell MS, Hockman D, Uy B, Buckley D, Sauka-Spengler T, Bronner ME, Baker CVH (2014) A fate-map for cranial sensory ganglia in the sea lamprey, Dev. Biol. 385, 405-416
Barraud P, St John JA, Stolt CC, Wegner M, Baker CVH (2013) Olfactory ensheathing glia are required for embryonic olfactory axon targeting and the migration of gonadotropin-releasing hormone neurons, Biology Open 2, 750-759
Gillis JA*, Modrell MS, Baker CVH (2013) Developmental evidence for serial homology of the vertebrate jaw and gill arch skeleton, Nature Communications 4, 1436. doi: 10.1038/ncomms2429 *Corresponding author
O'Neill P, Mak S-S, Fritzsch B, Ladher RK*, Baker CVH* (2012) The amniote paratympanic organ develops from a previously undiscovered sensory placode, Nature Communications 3, 1041. doi:10.1038/ncomms2036 *Joint corresponding authors
Gillis JA, Modrell MS, Northcutt RG, Catania KC, Luer CA, Baker CVH (2012) Electrosensory ampullary organs are derived from lateral line placodes in cartilaginous fishes, Development 139, 3142-3146
Modrell MS, Bemis WE, Northcutt RG, Davis MC, Baker CVH (2011) Electrosensory ampullary organs are derived from lateral line placodes in bony fishes, Nature Communications 2, 496. DOI:10.1038/ncomms1502
Barraud P, Seferiadis AA, Tyson LD, Zwart MF, Szabo-Rogers HL, Ruhrberg C, Liu KJ, Baker CVH (2010) Neural crest origin of olfactory ensheathing glia, Proc. Natl. Acad. Sci. U.S.A. 107, 21040-5
Dude CM, Kuan C-YK, Bradshaw JR, Greene NDE, Relaix F, Stark MR*, Baker CVH* (2009) Activation of Pax3 target genes is necessary but not sufficient for neurogenesis in the ophthalmic trigeminal placode, Dev. Biol. 326: 314-326 *Joint corresponding authors
Baker CVH (2008) The evolution and elaboration of vertebrate neural crest cells, Curr. Op. Genet. Dev. 18, 536-543
Xu H, Dude CM, Baker CVH (2008) Fine-grained fate maps for the ophthalmic and maxillomandibular trigeminal placodes in the chick embryo, Dev. Biol. 317, 174-186
O’Neill P, McCole RB, Baker CVH (2007) A molecular analysis of neurogenic placode and cranial sensory ganglion development in the shark, Scyliorhinus canicula Dev. Biol. 304, 156-181