Pascale Cossart


Pascale Cossart is a bacteriologist at the Pasteur Institute of Paris, and the foremost authority on Listeria monocytogenes, a deadly and common food-borne pathogen responsible for encephalitis, meningitis, bacteremia, gastroenteritis, and other diseases.

Biography

Cossart earned a B.S. and M.S. from Lille University in 1968. She then earned an M.S. in chemistry from Georgetown University in 1971, and her Ph.D. in biochemistry at the Pasteur Institute and the University of Paris in 1977. She completed her postdoctoral fellowship at the Pasteur Institute. She is currently a Professor and Head of the Unité des Interactions Bactéries Cellules at the Pasteur Institute. In 1998, she received the Richard Lounsbery Prize and the L'Oreal-UNESCO Award for Women in Science. She was awarded the Balzan Prize for Infectious Diseases: Basic and Clinical Aspects in 2013.

Works

Cossart's research has focused on infection by intracellular bacteria, and in particular the infectious agent Listeria monocytogenes.
Listeria is a food-borne bacterial pathogen responsible for numerous illnesses and a mortality rate of 30%. The bacteria is one of the best models of intracellular parasitism because it is particularly hardy, able to survive in a variety of cells, cross multiple host barriers, and spreads through ActA, the protein responsible for actin-based motility. Cossart's work has shed light on the genetic and biochemical processes that make Listeria so effective and lethal, identifying the bsh gene; regulatory mechanisms such as an RNA thermosensor that control expression of the virulence genes such as bsh; and the ways in which Listeria enters cells and crosses physiological barriers such as the blood–brain barrier, the intestinal barrier, and the placental barrier. The discovery by Cossart's lab of the interaction between L. monocytogenes' protein, internalin, and its cell receptor, E-cadherin, was the first such study that successfully demonstrated the molecular mechanism that permits a bacterial agent to cross the placental barrier.
In 2009 Cossart published what she describes as the first "bacterial operon map"—the transcriptional program that regulates Listeria's behavior in different environmental conditions. By comparing the sequences of Listeria drawn from soil and drawn from the human gut, Cossart identified non-coding RNAs that contribute to Listeria's virulence, identified additional RNA repressors, and determined that riboswitches can act both downstream and upstream.
As part of her work she has also developed important biological tools, including a transgenic mouse that was the first animal model to overcome bacterial species-specificity. The mouse carried a human version of a host cell membrane receptor that L. monocytogenes used to enter cells.

Significant publications