Blood cells are responsible for the maintenance and immune protection of nearly every cell type in the body. It is therefore unsurprising that this relentless work would require blood cells to self-renew. This self-renewal process begins with hematopoietic stem cells (HSCs). HSCs are responsible for the constant renewal of blood cells – reaching production values of billions of new cells each day. Basic research in the 1950’s looked to use this process of constant renewal to treat diseases.
Following initial success in disease states, HSC therapy worked its way into therapies for: cancer, immunodeficiencies, hematological diseases, and genetic disorders. One key issue in the use of HSCs for these therapies is the difficulty to expand cultures ex-vivo. Therefore, the identification of a method that would increase the number of transplantable stem cells obtained during the process of ex-vivo expansion, could propel the success of HSC cell-based therapy in several disease models.
Dr. Mikkola at UCLA has discovered a novel regulator of HSC differentiation that is specifically expressed on human HSCs, but not expressed on human stem/progenitor cells (HSPCs). When the marker is upregulated during ex-vivo expansion, the observed engraftment of these HSCs into immune-compromised mice is remarkably heightened. Furthermore, the overexpression of this factor did not reveal conferment of renewal properties to non-self-renewing hematopoietic progenitors. This observation suggests that overexpression of the factor does not reprogram the progenitors of HSCs or leukemic stem cells but instead enhances the self-renewal of undifferentiated HSPCs. Therefore, the discovery of this novel factor may be used to more efficiently expand human HSCs ex-vivo, improving HSC transplantation and its use for various disease models.
The invention has been tested during in-vitro studies, showing: that decreased expression of the novel factor leads to the loss of the proliferative capacity of HSCs, overexpression of the factor led to enhanced immunophenotypic HSPCs. Studies in-vivo in mouse models revealed that downregulation of the factor led to impaired HSC engraftment, while upregulation of the factor led to increased engraftment.
|United States Of America||Published Application||20190270967||09/05/2019||2016-990|
|European Patent Office||Published Application||3472306||04/24/2019||2016-990|
hematopoietic stem cells, HSC, HSPC, self-renewal, cell-based therapy, gene therapies, ex vivo stem cell expansion