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A Nose for Science

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Mouse Nasal Cavity
Credit: Lu Yang, David Ornitz, and Sung-Ho Huh, Washington University School of Medicine, St. Louis; University of Nebraska Medical Center, Omaha

Our nose does a lot more than take in oxygen, smell, and sometimes sniffle. This complex organ also helps us taste and, as many of us notice during spring allergy season when our noses get stuffy, it even provides some important anatomic features to enable us to speak clearly.

This colorful, almost psychedelic image shows the entire olfactory epithelium, or “smell center,” (green) inside the nasal cavity of a newborn mouse. The olfactory epithelium drapes over the interior walls of the nasal cavity and its curvy bony parts (red). Every cell in the nose contains DNA (blue).

The olfactory epithelium detects odorant molecules in the air, providing a sense of smell. In humans, the nose has about 400 types of scent receptors, and they can detect at least 1 trillion different odors [1].

But this is more than just a cool image captured by graduate student Lu Yang, who works with David Ornitz at Washington University School of Medicine, St. Louis. The two discovered a new type of progenitor cell, called a FEP cell, that has the capacity to generate the entire smell center [2]. Progenitor cells are made by stem cells. But they are capable of multiplying and producing various cells of a particular lineage that serve as the workforce for specialized tissues, such as the olfactory epithelium.

Yang and Ornitz also discovered that the FEP cells crank out a molecule, called FGF20, that controls the growth of the bony parts in the nasal cavity. This seems to regulate the size of the olfactory system, which has fascinating implications for understanding how many mammals possess a keener sense of smell than humans.

But it turns out that FGF20 does a lot more than control smell. While working in Ornitz’s lab as a postdoc, Sung-Ho Huh, now an assistant professor at the University of Nebraska Medical Center, Omaha, discovered that FGF20 helps form the cochlea [3]. This inner-ear region allows us to hear, and mice born without FGF20 are deaf. Other studies show that FGF20 is important for development of the kidney, teeth, mammary gland, and of specific types of hair [4-7]. Clearly, this indicates multi-tasking can be a key feature of a protein, not a trivial glitch.

The image was one of the winners in the 2018 BioArt Scientific Image & Video Competition, sponsored by the Federation of American Societies for Experimental Biology (FASEB). Its vibrant colors help to show the basics of smell, and remind us that every scientific picture tells a story.

References:

[1] Humans can discriminate more than 1 trillion olfactory stimuli. Bushdid C1, Magnasco MO, Vosshall LB, Keller A. Science. 2014 Mar 21;343(6177):1370-1372.

[2] FGF20-Expressing, Wnt-Responsive Olfactory Epithelial Progenitors Regulate Underlying Turbinate Growth to Optimize Surface Area. Yang LM, Huh SH, Ornitz DM. Dev Cell. 2018;46(5):564-580.

[3] Differentiation of the lateral compartment of the cochlea requires a temporally restricted FGF20 signal. Huh SH, Jones J, Warchol ME, Ornitz DM. PLoS Biol. 2012;10(1):e1001231.

[4] FGF9 and FGF20 maintain the stemness of nephron progenitors in mice and man. Barak H, Huh SH, Chen S, Jeanpierre C, Martinovic J, Parisot M, Bole-Feysot C, Nitschke P, Salomon R, Antignac C, Ornitz DM, Kopan R. Dev. Cell. 2012;22(6):1191-1207

[5] Ectodysplasin target gene Fgf20 regulates mammary bud growth and ductal invasion and branching during puberty. Elo T, Lindfors PH, Lan Q, Voutilainen M, Trela E, Ohlsson C, Huh SH, Ornitz DM, Poutanen M, Howard BA, Mikkola ML. Sci Rep. 2017;7(1):5049

[6] Ectodysplasin regulates activator-inhibitor balance in murine tooth development through Fgf20 signaling. D Haara O, Harjunmaa E, Lindfors PH, Huh SH, Fliniaux I, Aberg T, Jernvall J, Ornitz DM, Mikkola ML, Thesleff I. Development. 2012;139(17):3189-3199.

[7] Fgf20 governs formation of primary and secondary dermal condensations in developing hair follicles. Huh SH, Närhi K, Lindfors PH, Häärä O, Yang L, Ornitz DM, Mikkola ML. Genes Dev. 2013;27(4):450-458.

Links:

Taste and Smell (National Institute on Deafness and Other Communication Disorders/NIH)

Ornitz Lab, (Washington University, St. Louis)

Huh Lab, (University of Nebraska Medical Center, Omaha)

BioArt Scientific Image & Video Competition, (Federation of American Societies for Experimental Biology, Bethesda, MD)

NIH Support: National Heart, Lung, and Blood Institute; National Institute of Neurological Disorders and Stroke; National Institute on Deafness and Other Communication Disorders



LabTV: Curious About Genetics of Deafness

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Joseph FosterWhat do Miami, music, and genetic research have in common? They are all central to the life of Joseph Foster, the young researcher who’s in the spotlight for our next installment of LabTV.

Foster, a research associate in Mustafa Tekin’s lab at the University of Miami’s Hussman Institute for Human Genomics, is involved in the hunt for the remaining genes responsible for congenital forms of deafness.This area of research is a good fit for Foster. Not only does he have a keen interest in genetic diseases (a close family member was born with cystic fibrosis), he’s a musician with a deep appreciation of the gift of hearing—loving to play the saxophone in his free time.


Snapshots of Life: The Biological Basis of Hearing

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sensory hair cells in a chicken's ear

Credit: Peter Barr-Gillespie and Kateri Spinelli, Oregon Health & Science University, Portland

Did you know that chickens have ears? Well, here’s the evidence—you’re looking at a micrograph of sensory hair cells that make up the inner ear of Gallus gallus domesticus, otherwise known as the domestic chicken. Protruding from each hair cell is a tall bundle of stiff appendages, called stereocilia, that capture vibrations and enable the chicken to hear everything from grain being poured into a feeder to the footsteps of a wily fox. The flatter area is occupied by supporting cells, which have recently been shown to have the capacity to regenerate damaged or destroyed hair cells.

Peter Barr-Gillespie and Kateri Spinelli of Oregon Health & Science University, Portland used a scanning electron microscope to capture this image—one of the winners of the Federation of American Societies for Experimental Biology’s 2014 BioArt competition—while studying how these cells convert sound waves into brain waves. It is generally known that sound waves cause the stereocilia on each hair cell to oscillate in concert. These vibrating stereocilia trigger electrical changes in the hair cells, which then send signals to the brain. Barr-Gillespie’s group focuses on the actual molecules that build the stereocilia and translate the vibrations into brain signals.


Creative Minds: A Baby’s Eye View of Language Development

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Click to start videoIf you are a fan of wildlife shows, you’ve probably seen those tiny video cameras rigged to animals in the wild that provide a sneak peek into their secret domains. But not all research cams are mounted on creatures with fur, feathers, or fins. One of NIH’s 2014 Early Independence Award winners has developed a baby-friendly, head-mounted camera system (shown above) that captures the world from an infant’s perspective and explores one of our most human, but still imperfectly understood, traits: language.

Elika Bergelson

Elika Bergelson
Credit: Zachary T. Kern

Elika Bergelson, a young researcher at the University of Rochester in New York, wants to know exactly how and when infants acquire the ability to understand spoken words. Using innovative camera gear and other investigative tools, she hopes to refine current thinking about the natural timeline for language acquisition. Bergelson also hopes her work will pay off in a firmer theoretical foundation to help clinicians assess children with poor verbal skills or with neurodevelopmental conditions that impair information processing, such as autism spectrum disorders.


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