A Look in the Lab at The Stowers Institute for Medical Research

Zebrafish development: searching for clues to help overcome deafness.

Dr. Piotrowski talks about her lab’s research exploring zebrafish development, particularly the work they’ve done to understand the regenerative capabilities of zebrafish sensory cells and its relevance to human hearing.

 

The formation of the sensory lateral line — an example of collective cell migration.

This movie shows the collective migration of cells forming the lateral line primordium along the trunk of the zebrafish embryo over a 2-hour time period. A primordium refers to a structure at its earliest stage of development. As the lateral line primordium progresses, it periodically deposits clusters of cells that later form sensory organs composed of hair-like or ciliated cells. These cells of the lateral line primordium express green fluorescent protein, which allows researchers to visualize the development of this sensory system.

 

Three-dimensional reconstruction of a lateral line sensory organ.

The cells forming lateral line sensory organs are distinctly round and clustered. The most inner cells — the sensory hair cells — display hair-like structures called cilia that can sense motion in water. These cells express green fluorescent protein so they can be easily tracked.

 
 

Dr. Tatjana Piotrowski and her lab are interested in aspects of organ development in vertebrates and how organs maintain their function in adults. Some research areas for the lab include collective cell migration – how cells move as a group from one place in an organism to another – morphogenesis, or how an organism or part of an organism develops its shape – and how sensory cells regenerate in a mature organ.


The model system that the Piotrowski Lab uses to study these processes is the development of the sensory lateral line in zebrafish. Dotted along the length of the fish, this sensory organ helps them detect the motion of prey and predators in water. The lateral line is composed of cells that are similar in form and function to cells of the human inner ear that are important for hearing. Unlike our hearing cells, which can be permanently damaged resulting in deafness, the fish sensory cells are able to regenerate. By studying the regenerative cells of the zebrafish, the Piotrowski Lab hopes it will uncover key molecular regulatory pathways that will help unlock a cure for deafness in humans.

 

Magnification of cells in the tip of the migrating lateral line primordium.

To move through tissues, migrating cells extend finger-like protrusions in their environment that they use to sense guiding cues, such as signals from other cells or components of the extracellular space. The migrating cells establish temporary physical connections they use like anchor points to move themselves forward. As they migrate, the lateral line primordium cells maintain very close contact with each other as they exhibit a collective migration behavior. These cells express green fluorescent protein.

 

Regeneration of a neuromast.

This is a 22 hour long time lapse movie that shows how some cells divide (indicated by a colored dot) to give rise to two new hair cells (they turn on a green hair cell marker).

 

Model of a neuromast.

The neuromast is the main functional unit of the fish lateral line sensory organ. Composed of clustered ciliated cells that detect water motion, neuromasts play an important role In the behavioral response of fish.