KHSRP combines transcriptional and posttranscriptional mechanisms to regulate monocytic differentiation

RNA-binding proteins(RBPs)are widely involved in the transcriptional and posttranscriptional regulation of multiple biological processes.The transcriptional regulatory ability of RBPs was indicated by the identification of chromatin-enriched RBPs(Che-RBPs).One of these proteins,KH-type splicing regulatory protein(KHSRP),is a multifunctional RBP that has been implicated in mRNA decay,alternative splicing,and miRNA biogenesis and plays an essential role in myeloid differentiation by facilitating the maturation of miR-129.In this study,we revealed that KHSRP regulates monocytic differentiation by regulating gene transcription and RNA splicing.KHSRP-occupied specific genomic sites in promoter and enhancer regions to regulate the expression of several hematopoietic genes through transcriptional activation and bound to pre-mRNA intronic regions to modulate alternative splicing during monocytic differentiation.Of note,KHSRP had co-regulatory effects at both the transcriptional and posttranscriptional levels on MOGOH and ADARB1.Taken together,our analyses revealed the dual DNA-and RNA-binding activities of KHSRP and have provided a paradigm to guide the analysis of other functional Che-RBPs in different biological systems.

Expression of ICAT and Wnt signaling-related proteins in the monocytic differentiation of HL-60 cells induced by a new steroidal drug NSC67657

Objective To investigate the expression of mRNA and proteins ofβ-catenin,TCF-4(ICAT)and Wnt signaling pathway-related genes in the monocytic differentiation of acute myeloid leukemia HL-60 cells induced by a new steroidal drug NSC67657.Methods Wright’s staining andα-NBE staining were used to observe the differentiation of HL-60 cells after 5 days of

P48-Triggered transmembrane signaling transduction of human monocytes:mobilization of calcium ion and activation of protein kinase C(PKC)

P48 is a cytokine which induces monocyte differentia-tion and the induction of cytotoxic activity. In this study,the signal transduction events involved in the stimulation of monocytes with the membrane form of P48 (mP48) were investigated. Monocyte stimulation with mP48 was found to involve the mobilization of intracellular calcium (Ca2+)and the activation and translocation of PKC from the cy-tosol to the membrane. Membane P48 induced a rapid rise of intracellular Ca2+ in a dose dependent maner. Simi-larly the stimulation of monocytes with P48 was found to involve the activation and translocation of PKC. The translocation of PKC was rapid (within 0-5 min) yet tran-sient with PKC activity returning to control levels by 8 min. The functional role of protein kineses in P48 induced TNF secretion was studied using various kinese inhibitors. The PKC inhibitors, H-7 and sphingosine, were found to inhibit P48 induced TNF secretion with 50% inhibition at 5μM HA1004, which inhibts cyclic nucleotide-dependent kinase (PKA, Ki 1.2μM), did not inhibit TNF secretion. H-8 (PKA inhibitor) was found to be an effective inhibitor of TNF secretion only at high concentrations(30μp. The Calmodulin-dependent kinase inhibitor, W7 (Ki 12μM)was found to be effective at concentration above 5μM.These findings suggest that P48-triggered TNF secretion involves transmembrane Ca2+ signaling and the subse-quent activation of at least two protein kineses, PKC and CaMK.