Primary myelofibrosis is a myeloproliferative neoplasm associated with significant morbidity and mortality, for which effective therapies are lacking. β-Arrestins are multifunctional adaptor proteins involved in developmental signaling pathways. One isoform, β-arrestin2 (βarr2), has been implicated in initiation and progression of chronic myeloid leukemia, another myeloproliferative neoplasm closely related to primary myelofibrosis. Accordingly, we investigated the relationship between βarr2 and primary myelofibrosis. In a murine model of MPLW515L-mutant primary myelofibrosis, mice transplanted with donor βarr2-knockout (βarr2–/–) hematopoietic stem cells infected with MPL-mutant retrovirus did not develop myelofibrosis, whereas controls uniformly succumbed to disease. Although transplanted βarr2–/– cells homed properly to marrow, they did not repopulate long-term due to increased apoptosis and decreased self-renewal of βarr2–/– cells. In order to assess the effect of acute loss of βarr2 in established primary myelofibrosis in vivo, we utilized a tamoxifen-induced Cre-conditional βarr2-knockout mouse. Mice that received Cre (+) donor cells and developed myelofibrosis had significantly improved survival compared with controls. These data indicate that lack of antiapoptotic βarr2 mediates marrow failure of murine hematopoietic stem cells overexpressing MPLW515L. They also indicate that βarr2 is necessary for progression of primary myelofibrosis, suggesting that it may serve as a novel therapeutic target in this disease.
Lindsay A.M. Rein, James W. Wisler, Jihee Kim, Barbara Theriot, LiYin Huang, Trevor Price, Haeyoon Yang, Minyong Chen, Wei Chen, Dorothy Sipkins, Yuri Fedoriw, Julia K.L. Walker, Richard T. Premont, Robert J. Lefkowitz
Usage data is cumulative from December 2017 through December 2018.
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.