The lymphatic vasculature is essential for maintaining tissue fluid homeostasis, immunity, and is involved in multiple human diseases. In cancer, changes in lymphatic vessels, including lymphangiogenesis and remodelling of existing lymphatic vessels facilitate tumor metastasis. Furthermore, lymphangiogenesis occurs during wound healing and insufficient lymphatic vessel development results in secondary lymphedema. All these processes rely on the migration of lymphatic endothelial cells (LEC), however, the molecular mechanisms and related signalling pathways are still uncharacterized.
In a genome-wide functional siRNA screen performed previously in our laboratory, 90 genes were identified as active in the migration of primary human dermal micro-vascular neonatal LECs, and also as LEC-specific differential expression from lymph node undergoing lymphatic remodelling in vivo response to a viral infection model. Hence, this study is focused on determining and characterising novel candidate genes regulating LEC migration and identifying their related molecular mechanisms.
We looked at the related pathway information and compared different datasets of genes from the genome-wide screen. A total of 80 genes were tested in a simple scratch assay transfecting with siRNA SMARTpools to determine the migration ability of individual genes. There are 62 genes identified as active in LEC migration. The results of a deconvolution screen of individual siRNA duplexes comprising the SMARTpools for technical confirmation, show that 27 genes (e.g. VDR, BLM) are highly validated by a threshold of 2/4 duplexes emulating the migration phenotype of the SMARTpool in the scratch assay.
In the next step, these genes will be assessed in some patient-derived datasets and human samples which contain high number of lymphatic vessels, as well as undergoing further characterization in vitro and in vivo. Integrating all the information from primary cells, in vivo mouse models and human tissues, we aim to provide further insight into finding therapeutic targets to control lymphatic development in diseases.