Jiing Kuan Yee, Ph.D.

My current research focuses on three areas.

Study spinal muscular atrophy (SMA) in vitro with induced pluripotent stem cells (iPSCs).

SMA is caused by loss of the survival of motoneuron (SMN) protein, resulting in the selective degeneration of alpha motoneurons in spinal cord.  The exact mechanisms that cause motoneuron degeneration are not known. We have established five iPSC lines from the fibroblasts of a SMA patient.  Motoneurons derived from these iPSC lines exhibit abnormal neurite outgrowth and reduced survival in culture.  We are using the SMA iPSCs to study structural and functional deficits in derived motoneurons.  We are also investigating potential SMN downstream targets whose deficiencies induce motoneuron degeneration in SMA.

Study Wiskott-Aldrich Syndrome (WAS) in vitro with iPSCs.

WAS is an X-linked primary immunodeficiency disorder caused by mutations in the gene encoding Wiskott-Aldrich syndrome protein (WASp).  Patients with mutated WASp exhibit immunodeficiency and a significant fraction of them also develops autoimmune disorders and lymphomas.  The phenotypes caused by WASp deficiency vary among different hematopoietic lineages, and the mechanisms remain largely uncharacterized.  We have established fifteen WAS iPSC lines that serve to model the disease in vitro.  We are also employing site-specific gene editing as a strategy to rescue the WASp mutation in the established WAS iPSCs.  The rescued iPSC lines will serve as an isogenic control for disease phenotype studies.

Optimize gene editing systems to manipulate gene modification in human ESC and iPSC lines.

We are using the transcription activator-like effector nuclease (TALEN) and the clustered regularly interspaced short palindromic repeat (CRISPR) systems for site-specific gene editing.  These two systems create double-strand DNA breaks in the genome that either inactivate genes or stimulate homologous recombination and modify the target gene according to the input DNA template.  Using these two systems, we are carrying out optimization studies to maximize the gene editing efficiency in established cell lines and primary ESC/iPSC lines.  We will use these technologies to mark specific cell lineages for cell isolation and to correct genetic defects in iPSCs for potential stem cell-based therapy.