Tammy Haut Donahue

Projects

Response of Meniscal Cells to Fluid Flow Induced Shear Stress --How cells respond to a mechanical stimulus such as fluid flow is called mechanotransduction.

Description:

The long-term goal the Mechanotransduction Research Group (MRG) is to detail and further the scientific understanding of mechanotransduction processes i.e. the molecular basis of how mechanical stresses are converted into biological signals and physiological responses.

The MRG provides opportunities for interdisciplinary research in areas of finite element modeling, biomedical engineering, cell biology, and molecular physiology. Participation is open to faculty interested in interdisciplinary projects.

Faculty and graduate students from biological sciences, biomedical engineering, and mechanical engineering are involved in a variety of projects including: improving the treatment of arthritis, understanding bone fracture healing and growth, improvement of orthopaedic surgical procedures and understanding contractile signal transduction in striated muscle.

Background:

During evolution, mechanical stimulation, as well as other physical factors such as temperature, pH, and light has been a critical environmental signal sensed by cells.

It is plausible that the intracellular signal transduction pathways originally developed by cells to respond to those basic physical stimuli have been preserved during evolution and further developed to respond to other external stimuli.

Thus the biochemical reactions involved in mechanotransduction may be shared by other stimuli. The signaling events initiated by mechanical stimulation include generation of second messengers, change of phosphorylation status of proteins, amplification through enzymatic cascades, and transmission via a complicated network of signaling molecules.

Mission:

Our research aims to expand our understanding of how organisms sense and respond to mechanical stimulation.

Although the property of mechanotransduction is usually associated with the specialized sensory cells involved in hearing, balance, proprioception and touch, it is in fact a general property exhibited by cells when they are touched, rubbed, flexed, stretched, compressed or vibrated.

Such stimulation can arise both externally, as in the flexing of plants and trees by the wind and rain, or internally, as in the rhythmic pulsing of blood against the walls of the vascular system, and can profoundly influence the growth, development and functioning of plants and animals alike.

In humans and other mammals, mechanotransduction is critically involved in the bone-building processes elicited by the compressive force of gravity on the skeleton; in the normal and pathological (e.g. atherosclerotic) responses of the vascular lining to the sheer forces generated by flowing blood; in modifying the structure and properties of skeletal muscle in response to overload, or the enlargement of an over-worked heart (cardiac hypertrophy) in response to elevated blood pressure.

As for plants, horticulturists and farmers have long appreciated that wind-induced flexing decreases both the size and yield of crop plants, and that mechanostimulation in general slows the development of plants. In addition, it has been shown further that mechanical perturbation affects a plant's differentiation and its responses to many other environmental stimuli, such as gravity, light, cold and drought stress.

Research:

The Mechanotransduction Research Group provides opportunities for interdisciplinary research in areas of cell physiology, signal transduction, molecular biology, biomedical engineering, and mechanical engineering.

Faculty and graduate students from the departments of Biological sciences, Biomedical engineering, Mechanical engineering and Forestry are involved in a variety of projects related to how cells sense and respond to the external development. Studies are conducted using a variety of in vivo, in vitro and ex vitro models.