Prof. Jan Hoh, Johns Hopkins School of Medicine

Abstract

I will give an overview of my research by presenting findings from three projects.  1. Living cells have complex mechanical properties, and the molecular basis for how these properties are established is major problem in cellular biophysics.  My coworkers and I have discovered a novel mechanism by which the compressive mechanics in motor neurons arise from disordered domains of specific proteins (neurofilaments).  These cells resist compression due to a reduction of chain entropy in the neurofilaments. 2.  Removing cells from their natural environments in organs and tissues, and growing them in a Petri dish, dramatically improves experimental access to the cells.  But it also removes natural signals that cells need to respond appropriately to interventions.  Our recent efforts to address natural gradients of molecules such as oxygen and glucose in cell culture models will be discussed.  3.  As an embryo develops it grows from 1 cell to many thousands of cells, and as the number of cells increases they arrange themselves in increasingly complex ways (tissues and organs).  At present development is quantified by staging, where morphological characteristics at each time point are used to define stages – and dynamics of development are described by time to or between stages.  But this approach has serious limitations.  We have recently developed a new metric for spatial information that allows a new and more quantitative perspective on the problem.