cilia
Using Frogs to Tackle Kidney Problems
Posted on by Dr. Francis Collins

Many human cells are adorned with hair-like projections called cilia. Scientists now realize that these specialized structures play many important roles throughout the body, including directing or sensing various signals such as fluid flow. Their improper function has been linked to a wide range of health conditions, such as kidney disease, scoliosis, and obesity.
Studying cilia in people can be pretty challenging. It’s less tricky in a commonly used model organism: Xenopus laevis, or the African clawed frog. This image highlights a healthy patch of motile cilia (yellow) on embryonic skin cells (red) of Xenopus laevis. The cilia found in humans and all other vertebrates are built from essentially the same elongated structures known as microtubules. That’s why researchers can learn a lot about human cilia by studying frogs.
Scoliosis Traced to Problems in Spinal Fluid Flow
Posted on by Dr. Francis Collins

Caption: Normal zebrafish (top left) and a normal skeleton (bottom left); zebrafish with scoliosis (top right) and an abnormal scoliotic skeleton (bottom right).
Credit: Grimes DT, Boswell CW, Morante NF, Henkelman RM.
Many of us may remember undergoing a simple screening test in school to look for abnormal curvatures of the spine. The condition known as adolescent idiopathic scoliosis (IS) affects 3 percent of children, typically showing up in the tween or early teen years when kids are growing rapidly. While scoliosis can occur due to physical defects in bones or muscles, more often the C- or S-shaped spinal curves develop for unknown reasons. Because the basic biological mechanisms of IS have been poorly understood, treatment to prevent further progression and potentially painful disfigurement has been limited to restrictive braces or corrective surgery.
Now, in work involving zebrafish models of IS, a team of NIH-funded researchers and their colleagues report a surprising discovery that suggests it may be possible to develop more precisely targeted therapeutics to reduce or even prevent scoliosis. The team’s experiments have, for the first time, shown that mutation of a gene associated with spinal curvature in both zebrafish and humans has its effect by altering the function of the tiny hair-like projections, known as cilia, that line the spinal cord. Without the cilia’s normal, beating movements, the fluid that bathes the brain and spinal cord doesn’t flow properly, and zebrafish develop abnormal spinal curves that look much like those seen in kids with scoliosis. However, when the researchers used genetic engineering to correct such mutations and thereby restore normal cilia function and flow of cerebral spinal fluid (CSF), the zebrafish did not develop spinal curvature.
Cool Videos: A Look Inside a Mouse’s Lung
Posted on by Dr. Francis Collins
If you have ever wondered what it is like to be an oxygen molecule inhaled through the lungs, here is your chance to find out! In this movie, we take a fantastic voyage through the slippery airways of the adult mouse lung.
We begin at the top in the main pipeline, called the bronchus, just below the trachea and wind through a system of increasingly narrow tubes. As you zoom through the airways, take note of the cilia (seen as goldish streaks); these tiny, hair-like structures move dust, germs, and mucus from smaller air passages to larger ones. Our quick trip concludes with a look into the alveoli — the air sacs where oxygen is delivered to red blood cells and carbon dioxide is removed and exhaled.