Stromal-derived factor-1 and its receptor, XXXX , are constitutively expressed by mouse liver sinusoidal endothelial cells: implications for the regulation of hematopoietic cell migration to the liver during extramedullary hematopoiesis.

@entity9019 @entity9843 @entity19149 @entity5231
@entity19149 is the main regulating factor for trafficking/homing of hematopoietic stem cells (HSC) to the bone marrow (BM). It is possible that this chemokine may also play a fundamental role in regulating the migration of HSC to several organs during extramedullary hematopoiesis. Because liver sinusoidal endothelial cells (LSEC) constitute an extramedullary niche for HSC, it is possible that these cells represent one of the main cellular sources of @entity19149 at the liver. Here, we show that LSEC express @entity19149 at the mRNA and protein level. Biological assays showed that conditioned medium from LSEC (LSEC-CM) stimulated the migration of BM progenitor lineage-negative (BM/Lin   ) cells. This effect was significantly reduced by @entity9019 , indicating that the @entity19149 / @entity9843 axis is involved in the stimulatory migrating effect induced by LSEC-CM. Early localization of HSC in @entity19149 -expressing LSEC microenvironment together with increased levels of this chemokine in hepatic homogenates was found in an experimental model of liver extramedullary hematopoiesis. Flow cytometry studies showed that LSEC express the @entity9843 receptor. Functional assays showed that activation of this receptor by @entity19149 stimulated the migration of LSEC and increased the expression of @entity5231 . Our findings suggest that LSEC through the production of @entity19149 may constitute a fundamental niche for regulation of HSC migration to the liver. To our knowledge, this is the first report showing that LSEC not only express and secrete @entity19149 , but also its receptor @entity9843 .
