There are trash bins in our homes, on our streets, and even as a popular icon on our desktop computers. And as this colorful image shows, trash bins of the cellular variety are also important in the brain.
This image—a winner in the Federation of American Societies for Experimental Biology’s 2017 BioArt competition—shows the brain of an adult zebrafish, a popular organism for studying how the brain works. It captures dense networks of blood vessels (red) lining the outer surface of the brain. Next to many of these vessels sit previously little-studied cells called fluorescent granular perithelial cells (yellowish green). Researchers now believe these cells, often shortened to FGPs, act much like trash receptacles that continuously take in and store waste products to keep the brain tidy and functioning well.
Certain organisms have remarkable abilities to achieve self-healing, and a fascinating example is the zebrafish (Danio rerio), a species of tropical freshwater fish that’s an increasingly popular model organism for biological research. When the fish’s spinal cord is severed, something remarkable happens that doesn’t occur in humans: supportive cells in the nervous system bridge the gap, allowing new nerve tissue to restore the spinal cord to full function within weeks.
Pretty incredible, but how does this occur? NIH-funded researchers have just found an important clue. They’ve discovered that the zebrafish’s damaged cells secrete a molecule known as connective tissue growth factor a (CTGFa) that is essential in regenerating its severed spinal cord. What’s particularly encouraging to those looking for ways to help the 12,000 Americans who suffer spinal cord injuries each year is that humans also produce a form of CTGF. In fact, the researchers found that applying human CTGF near the injured site even accelerated the regenerative process in zebrafish. While this growth factor by itself is unlikely to produce significant spinal cord regeneration in human patients, the findings do offer a promising lead for researchers pursuing the next generation of regenerative therapies.
Tags: connective tissue growth factor a, CTGF, Danio rerio, fish, glia, glial bridges, glial cells, growth factor, model organisms, nerve cells, nervous system, regenerative medicine, self-healing, spinal cord, spinal cord injuries, tissue engineering, tissue regeneration, traumatic injury, wound healing, zebrafish
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.
Tags: adolescence, adolescent idiopathic scoliosis, cerebral spinal fluid, childhood disorder, cilia, CSF, CSF flow, human development, model organisms, musculoskeletal disorder, ptk7 gene, scoliosis, spinal curvature, zebrafish
Modern sculptors might want to take a few notes from Mother Nature. The striking, stone-like forms that you see above are a micrograph of flower buds from the mustard plant Arabidopsis thaliana, which serves as an important model organism in biomedical research. In the center are the shoot apical meristems, consisting of undifferentiated stem cells (gray) that give rise to the flowers. Around the edge are buds that are several hours older, in which the flowers have just begun to form off of the shoot apical meristems. And, to the bottom left, are four structures that are the early sepals that will surround the fully formed flower that will bloom in a few weeks. The colored circles indicate areas of gene activity involved in determining the gender of the resulting flower, with masculinizing genes marked in green and feminizing in red.
This image, a winner in the Federation of American Societies for Experimental Biology’s 2015 BioArt competition, is the creation of postdoctoral student Nathanaёl Prunet, now in the NIH-supported lab of Elliot Meyerowitz at the California Institute of Technology, Pasadena, CA. Using scanning electron microscopy, Prunet snapped multiple 2D photographs of Arabidopsis buds at different tissue depths and computationally combined them to produce this 3D image.
Tags: Arabidopsis, Arabidopsis thaliana, development, FASEB Bioart 2015, flowers, genomics, model organisms, mustard plant, nutrition, pattern formation, plant biology, plants, regenerative medicine, sepal, shoot apical meristems