Dr. Shum’s research in epithelial cell biology and reproductive physiology focuses on the epididymal function in sperm maturation and male reproduction. Disorders of epididymal cellular function are known to associate with male infertility and may be the cause behind some idiopathic cases. Spermatozoa are infertile naturally when released from testis and yet become functionally competent during epididymal transit. Epididymis is thus essential for sperm maturation and male fertility as well as the health of offspring. The epididymal function is conferred by the layer of epithelial cells that lines in the luminal cavity of the organ, in which spermatozoa transit and mature in a protected microenvironment. Epididymal epithelial cells are the front line for the establishment of the epididymal-blood barrier that separates the luminal spermatozoa from the body contents. Defects in epididymal function are associated with poor sperm quality, male infertility, and some non-communicable diseases inherited by the subsequent generations. The ultimate goal of the Shum Lab is to elucidate the epithelial cell biology in epididymal functions and to provide theoretical support and new insights for better understanding of reproductive physiology and the development of medical diagnostics and therapies, and to explore the potential applications in medicine.
The research direction of the Shum Lab focuses on two main themes:
1) Elucidating epithelial cell function in the formation and maintenance of microenvironment during sperm maturation in epididymis；
2) Identify of epididymal-dependent signals for functional modification of intrinsic testicular factors of spermatozoa.
The firs theme focuses on the functional mechanism of epithelial cells in the formation and maintenance of epididymal microenvironment, particularly the network of intercellular signaling and cell-cell interactions amongst epithelial cells as well as amongst epithelial cells and spermatozoa in secretion and transportation function of epithelial cells, and the risk implications when such network is dysregulated in disease. The second theme focuses on the functional role of epididymal microenvironmental factors in modification of intrinsic factors of testicular spermatozoa, including ions, proteins, lipids and ncRNAs.