Acute renal allograft rejection is a common complication after renal transplantation that often leads to chronic rejection and ultimate graft loss. While renal allograft biopsy remains the gold standard for diagnosis of acute rejection, the possibility of biopsy-associated complications cannot be overlooked. The development of noninvasive methods for accurate detection of acute renal allograft rejection is thus of significant clinical importance. Gas chromatography–mass spectrometry (GC/MS) was employed for analysis of urine metabolites in 15 renal allograft recipients with acute rejection and 15 stable renal transplant recipients. Partial least squares (PLS) regression and leave-one-out analyses were performed to ascertain whether the metabolites identified could be exploited to distinguish acute rejection from stable groups as well as their sensitivity and specificity. Overall, 14 metabolites were significantly altered in the acute rejection group (11 and 3 metabolites displayed higher and lower levels, respectively) relative to the stable transplant group. Data from PLS and leave-one-out analyses revealed that the differential metabolites identified not only distinguished acute rejection from stable transplant recipients but also showed high sensitivity and specificity for diagnosis of renal allograft recipients with acute rejection. Urine metabolites identified with GC/MS can effectively distinguish acute rejection from stable transplant recipients, supporting the potential utility of metabolome analysis in non-invasive diagnosis of acute rejection.

Ectopic Viral Integration site 1 (EVI1) upregulation is implicated in 10–25% of pediatric acute myeloid leukemia (AML) and has an inferior outcome with current chemotherapy regimens. Here we report that EVI1 upregulation is associated with methylation of the miR-9 promoter and correlated with downregulation of miR-9 in human AML cell lines and bone marrow (BM) cells from pediatric patients. Reactivation of miR-9 by hypomethylating agents and forced expression of miR-9 in EVI1high leukemia cell lines and primary leukemia cells results in apoptosis and decreased proliferation of EVI1high leukemia cells. Furthermore, re-expression of miR-9 delays disease progression in EVI1high leukemia-xenograft mice. Our results suggest that EVI1-induced hypermethylation and downregulation of the miR-9 plays an important role in leukemogenesis in EVI-1high pediatric AML, indicating that hypomethylating agents may be a potential therapeutic strategy for EVI1high pediatric AML.

Ecotropic viral integration site 1 (EVI1/MECOM) is frequently upregulated in myeloid malignancies. Here, we present an Evi1-transgenic mouse model with inducible expression in hematopoietic stem/progenitor cells (HSPCs). Upon induction of Evi1 expression, mice displayed anemia, thrombocytopenia, lymphopenia, and erythroid and megakaryocyte dysplasia with a significant expansion of committed myeloid progenitor cells, resembling human myelodysplastic syndrome/myeloproliferative neoplasm–like (MDS/MPN–like) disease. Evi1 overexpression prompted HSPCs to exit quiescence and accelerated their proliferation, leading to expansion of committed myeloid progenitors while inhibiting lymphopoiesis. Analysis of global gene expression and Evi1 binding site profiling in HSPCs revealed that Evi1 directly upregulated lysine demethylase 6b (Kdm6b). Subsequently, Kdm6b-mediated H3K27me3 demethylation resulted in activation of various genes, including Laptm4b . Interestingly, KDM6B and LAPTM4B are positively correlated with EVI1 expression in patients with MDS. The EVI1/KDM6B/H3K27me3/LAPTM4B signaling pathway was also identified in EVI1 ^hi human leukemia cell lines. We found that hyperactivation of the LAPTM4B-driven mTOR pathway was crucial for the growth of EVI1 ^hi leukemia cells. Knockdown of Laptm4b partially rescued Evi1-induced abnormal hematopoiesis in vivo. Thus, our study establishes a mouse model to investigate EVI1 ^hi myeloid malignancies, demonstrating the significance of the EVI1-mediated KDM6B/H3K27me3/LAPTM4B signaling axis in their maintenance.

The SENOMAC trial has resolved the longstanding clinical debate regarding the omission of axillary lymph node dissection (ALND) in patients with 1–2