Robin Krimm, Ph.D.

Robin Krimm, Ph.D.

Robin Krimm, Ph.D.

Professor, Department of Anatomical Sciences & Neurobiology

Phone: (502) 852-3059
Email


 

Research Focus

Taste receptor cells detect chemical information (e.g. sweet or salty) in the food we eat; these cells connect to sensory neurons which carry this information to the brain.  Taste receptor cells exist as different types, each transducing one or several chemicals.  But it is unclear if the neurons that form connections with taste receptor cells exist as types or whether each neuron connects to one or multiple taste receptor cell types.  We are interested in defining the morphology of individual gustatory neurons, their pattern of connections, and how this pattern forms during development. One of the unique features of the adult taste system is that taste receptors die and are continuously replaced.  Therefore, the mechanisms which coordinate connectivity during development could also function in adulthood, and so we are also testing this hypothesis.  We are using a combination of sparse cell genetic labeling and fiber tracing, whole mount imaging, intra vital imaging, electrophysiology and behavior to tackle these problems. These studies will inform fundamental questions in the field of taste such as: What is the neural code for taste information?  How is this code maintained in a system where the receptor cell are continuously renewed?  Understanding these basic issues is a prerequisite to trying to repair damage to this system.

Current Projects:

1)      We determined previously that the neurotrophin brain-derived neurotrophic factor (BDNF) is important for the initial innervation of taste receptor cells by nerve fibers during embryonic development.  We are now focused on testing the hypothesis that, in adulthood, BDNF is expressed in a subtype of taste receptor cells and coordinates connections between a specific population of taste receptor cells (BDNF-expressing) and a specific population of nerve fibers (those that express the receptor for BDNF -TrkB).  We are also asking if BDNF-TrkB signaling is required for normal taste function.

2)      We are using sparse cell genetic labeling to determine if taste neurons exist as different morphological types based on how many and what type of taste receptor cells they connect with. This approach will be used to determine if this connectivity remodels during development and if so, the mechanisms that underlie this remodeling.

3)      We have recently become interested in defining the non-taste neurons that innervate fungiform papillae. We would like to define their morphologies, peripheral functional characteristics, and determine if they interact with taste neurons centrally.

 

Key Publications

Ohman-Gault, L. Huang, T. and Krimm R.F. 2017. The transcription factor Phox2b distinguishes between oral and non-oral sensory neurons in the geniculate ganglion. J Comp. Neurol. 525(18):3935-3950.

Tang, T., Rios-Pilier, J. and Krimm, R. F. 2017. Taste bud derived BDNF maintains innervation of a subset of TrkB-expressing gustatory nerve fibers. Mol Cell Neurosci. 82:195-203.

Meng, L., Huang, T., Sun C., Hill, D.L. and Krimm, R. F. 2017. BDNF is required for taste axon regeneration and contralateral plasticity following unilateral chorda tympani nerve section. Exp. Neurol. 293:27-42.

Huang, T. Ma, L, and R.F. Krimm, 2015. Postnatal reduction of BDNF regulates the developmental remodeling of taste bud innervation. Developmental Biology, 405(2)225-36.

Fei, D,  Huang, T and R. F. Krimm. 2014. The neurotrophin receptor p75 regulates gustatory axon branching and promotes innervation of the tongue during development. Neural Dev.  9:15

Huang, T and RF. Krimm.2014. BDNF and NT4 play interchangeable roles in gustatory development.Dev. Biology. 386(2):308-20.

Fei, D and R. F. Krimm. 2013. Taste neurons consist of both a large TrkB-receptor-dependent and a small TrkB-receptor-independent subpopulation. Plos One. 8(12): e83460.

Patel, A.V. and R. F. Krimm. 2012. Neurotrophin-4 regulates the survival of gustatory neurons earlier in development using a different mechanism than brain-derived neurotrophic factor. Dev. Biology 365(1):50-60.

Huang, T and RF. Krimm. 2010.  Developmental expression of bdnf, nt4 and trkB, in the mouse peripheral taste system. Dev. Dynamics. 239(10):2637-46.

Patel A.V., Huang T., Krimm R.F. (2010) Lingual and palatal gustatory afferents each depend on both BDNF and NT-4, but dependence is greater for lingual than palatal afferents. J. Comp Neurol., 518(16):3290-301.

Patel A.V., and Krimm R.F. (2010) BDNF is required the survival of differentiated geniculate ganglion neurons. Dev. Biology 340(2):419-29.

Thirumangalathu S., Harlow D.E., Driskell A.L., Krimm R.F., Barlow L.A. (2009) Fate mapping of mammalian embryonic taste bud progenitors. Development 136(9):1519-28.

Ma L., Lopez G.F., Krimm R.F. (2009) Epithelial-derived brain-derived neurotrophic factor is required for gustatory neuron targeting during a critical developmental period. J Neurosci., 29:3354-64.