Bone morphogenetic proteins (BMPs) and transforming growth factor beta TGFβ play a key role in various physiological and pathological processes, such as organ development and cancer. The biological signal induced by these proteins results in the expression of the pSMAD factor in the cell nucleus. Typically, this signal activation is measured by the Western blot assay, which provides average information for all cells.
In order to monitor the pSMAD biological signal for each cell and for a wide range of conditions, we have developed an assay based on fluorescence microscopy. This automated assay makes it possible to analyze cell images and quantify the pSMAD factor individually within each cell.
The immuno-fluorescence test meets the same requirements as the Western blot test.
We performed a kinetic study of pSmad activity in response to its activation by BMP/TGFb proteins, using 96-well microplates. Proteins are presented either directly in solution in the culture medium, or via a biomaterial deposited at the bottom of each well.
In addition, we have tested drugs targeting the biological signal induced by BMP/TGFb proteins.
This imaging technique can be applied to the study of other biological signals within cells, in response to stimulation by various proteins playing a physiological or pathological role.