a member of the Institute for Cell Engineering and
the department of Biomedical Engineering

The Cahan Lab is an interdisciplinary group that primarily devises and tests computational tools to address fundamental questions in the fields of stem cell engineering, developmental biology, and cancer biology. We are a new lab and are always looking for new members. Graduate students in the JHU Biomedical Engineering or Biological Chemistry and Molecular Biology PhD programs who are interested in joining are encouraged to to discuss rotations.

Gene Regulatory Networks

Gene regulatory networks (GRNs), encoded in the genome of an organism, define the complete set of regulatory relationships among genes and gene products. GRNs govern the cell’s transcriptional output both at steady state and in response to perturbations, and thus act as major molecular determinants of cell-type identity. The study of GRNs is a central and unifying component of our research program. We are actively developing new algorithms to reconstruct GRNs, to measure their establishment, to infer their dynamics, and to model intercellular regulatory networks. We are especially interested in understanding how cell type specific GRNs are established during development and we use the articular chondrocyte and hematopoietic stem cell to explore this topic.

The assessment question

To what extent is a cell population, derived via directed differentiation of pluripotent stem cells or via direct conversion between somatic cells, equivalent to the desired cell type? Patrick developed a computational platform (called CellNet) that uses GRNs to address this question during his postdoctoral fellowship. Now, the lab is extending this platform to different data types (e.g. bulk and single cell RNA-Seq) and sources, and enhancing it so that it can be applied to assess models of human cancers.

The improvement problem

Several lessons emerged from Patrick's application of CellNet to gene expression data of all compatible cell-engineering experiments in the public domain. First, he and his colleagues found that cells derived by directed differentiation approached their in vivo target cell types more closely than those derived through direct conversion. Second, they found that the GRNs of the starting cell type frequently are maintained in engineered cells. Third, they documented the substantial improvement of target cell type GRN status when cell fate engineering was practiced in situ, or after engineered cells were transplanted into their native niche. Finally, they documented the aberrant establishment of GRNs of other cell types (neither the starting or the target) in engineered cells. These insights are guiding his lab's efforts to develop generic systems to improve cell fate engineering protocols. Most of these efforts are based on GRNs and involve devising algorithms that predict the identity and timing of transcriptional regulator, microRNA, and signaling pathway modulations.

  • New Website is live!

    September 8th, 2016

    Also check out our twitter page for the latest news from our lab.

  • New Member: Emily Lo

    August 22nd, 2016

    Emily Lo joins us from the University of Washington in Seattle with her undergraduate degree in Molecular, Cellular, and Developmental Biology. She is coadvised by the Feinberg lab.

  • New Member: Remy Schwab

    July 18th, 2016

    Remy Schwab joins us from McGill University in Montreal with undergraduate degrees in Chemistry and Economics.

  • New Member: Yuqi Tan

    May 27th, 2016

    Yuqi Tan joins us from the Chinese University of Hong Kong after completing her undergraduate degree in Cell and Molecular Biology.

  • Publication!

    May 5th, 2016

    Qin Bian's review, Computational Tools for Stem Cell Biology, is accepted to Trends in Biotechnology.

  • Laboratory Renovations Complete

    February 15th, 2016

    Fully equipped with a Cell Tissue Culture room, wetlab, and a beautiful office space for our computational biologists.

  • New Member: Abby Spangler

    February 2nd, 2016

    Abby Spangler joins us from Florida State University after completing her undergraduate degree in Marine Biology.

  • New Member: Qin Bian

    December 2nd, 2015

    Qin Bian joins us from the Shanghai University of Traditional Chinese Medicine.

  • New Member: Pavithra Kumar

    September 9th, 2015

    Our first member, Pavithra Kumar, joins us from SASTRA University in India with a degree in Bioengineering.

  • A Lab is Born

    September 1st, 2015

    Patrick Cahan's first day at JHMI!

Watch our Video