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Philadelphia-chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is characterized by reciprocal chromosomal translocation between chromosome 9 and 22, leading to the expression of constitutively active oncogenic BCR–ABL1 fusion protein. CXC chemokine receptor 4 (CXCR4) is essential for the survival of BCR–ABL1-transformed mouse pre-B cells, as the deletion of CXCR4 induces death in these cells. To investigate whether CXCR4 inhibition also effectively blocks BCR–ABL1-transformed cell growth in vitro, in this study, we explored an array of peptide-based inhibitors of CXCR4. The inhibitors were optimized derivatives of EPI-X4, an endogenous peptide antagonist of CXCR4. We observed that among all the candidates, EPI-X4 JM#170 (referred to as JM#170) effectively induced cell death in BCR–ABL1-transformed mouse B cells but had little effect on untransformed wild-type B cells. Importantly, AMD3100, a small molecule inhibitor of CXCR4, did not show this effect. Treatment with JM#170 induced transient JNK phosphorylation in BCR–ABL1-transformed cells, which in turn activated the intrinsic apoptotic pathway by inducing cJun, Bim, and Bax gene expressions. Combinatorial treatment of JM#170 with ABL1 kinase inhibitor Imatinib exerted a stronger killing effect on BCR–ABL1-transformed cells even at a lower dose of Imatinib. Surprisingly, JM#170 actively killed Sup-B15 cells, a BCR–ABL1+ human ALL cell line, but had no effect on the BCR–ABL1− 697 cell line. This suggests that the inhibitory effect of JM#170 is specific for BCR–ABL1+ ALL. Taken together, JM#170 emerges as a potent novel drug against Ph+ ALL. [ABSTRACT FROM AUTHOR]

Abstract Background HIP1 Protein Interactor (HIPPI) is a pro-apoptotic protein that induces Caspase8 mediated apoptosis in cell. We have shown earlier that HIPPI could interact with a specific 9 bp sequence motif, defined as the HIPPI binding site (HBS), present in the upstream promoter of Caspase1 gene and regulate its expression. We also have shown that HIPPI, without any known nuclear localization signal, could be transported to the nucleus by HIP1, a NLS containing nucleo-cytoplasmic shuttling protein. Thus our present work aims at the investigation of the role of HIPPI as a global transcription regulator. Results We carried out genome wide search for the presence of HBS in the upstream sequences of genes. Our result suggests that HBS was predominantly located within 2 Kb upstream from transcription start site. Transcription factors like CREBP1, TBP, OCT1, EVI1 and P53 half site were significantly enriched in the 100 bp vicinity of HBS indicating that they might co-operate with HIPPI for transcription regulation. To illustrate the role of HIPPI on transcriptome, we performed gene expression profiling by microarray. Exogenous expression of HIPPI in HeLa cells resulted in up-regulation of 580 genes (p < 0.05) while 457 genes were down-regulated. Several transcription factors including CBP, REST, C/EBP beta were altered by HIPPI in this study. HIPPI also interacted with P53 in the protein level. This interaction occurred exclusively in the nuclear compartment and was absent in cells where HIP1 was knocked down. HIPPI-P53 interaction was necessary for HIPPI mediated up-regulation of Caspase1 gene. Finally, we analyzed published microarray data obtained with post mortem brains of Huntington's disease (HD) patients to investigate the possible involvement of HIPPI in HD pathogenesis. We observed that along with the transcription factors like CREB, P300, SREBP1, Sp1 etc. which are already known to be involved in HD, HIPPI binding site was also significantly over-represented in the upstream sequences of genes altered in HD. Conclusions Taken together, the results suggest that HIPPI could act as an important transcription regulator in cell regulating a vast array of genes, particularly transcription factors and at least, in part, play a role in transcription deregulation observed in HD.

Earlier we have shown that the proapoptotic protein HIPPI (huntingtin interacting protein 1 (HIP1) protein interactor) along with its molecular partner HIP1 could regulate transcription of the caspase-1 gene. Here we report that RE1-silencing transcription factor/neuron-restrictive silencer factor (REST/ NRSF) is a new transcriptional target of HIPPI. HIPPI could bind to the promoter of REST and increased its expression in neuronal as well as non-neuronal cells. Such activation of REST down-regulated expression of REST target genes, such as brain- derived neurotrophic factor (BDNF) or proenkephalin (PENK). The ability of HIPPI to activate REST gene transcription was dependent on HIP 1, the nuclear transporter of HIPPI. Using a Huntington disease cell model, we have demonstrated that feeble interaction of HIP1 with mutant huntingtin protein resulted in increased nuclear accumulation of HIPPI and HIP1, leading to higher occupancy of HIPPI at the REST promoter, triggering its transcriptional activation and consequent repression of REST target genes. This novel transcription regulatory mechanism of REST by HIPPI may contribute to the deregulation of transcription observed in the cell model of Huntington disease. [ABSTRACT FROM AUTHOR]

Summary Microglia as tissue macrophages contribute to the defense and maintenance of central nervous system (CNS) homeostasis. Little is known about the epigenetic signals controlling microglia function in vivo . We employed constitutive and inducible mutagenesis in microglia to delete two class I histone deacetylases, Hdac1 and Hdac2. Prenatal ablation of Hdac1 and Hdac2 impaired microglial development. Mechanistically, the promoters of pro-apoptotic and cell cycle genes were hyperacetylated in absence of Hdac1 and Hdac2, leading to increased apoptosis and reduced survival. In contrast, Hdac1 and Hdac2 were not required for adult microglia survival during homeostasis. In a mouse model of Alzheimer’s disease, deletion of Hdac1 and Hdac2 in microglia, but not in neuroectodermal cells, resulted in a decrease in amyloid load and improved cognitive impairment by enhancing microglial amyloid phagocytosis. Collectively, we report a role for epigenetic factors that differentially affect microglia development, homeostasis, and disease that could potentially be utilized therapeutically. [ABSTRACT FROM AUTHOR]

The prognosis of chronic lymphocytic leukemia (CLL) depends on different markers, including cytogenetic aberrations, oncogenic mutations, and mutational status of the immunoglobulin (Ig) heavy-chain variable (IGHV) gene. The number of IGHV mutations distinguishes mutated (M) CLL with a markedly superior prognosis from unmutated (UM) CLL cases. In addition, B cell antigen receptor (BCR) stereotypes as defined by IGHV usage and complementarity-determining regions (CDRs) classify ∼30% of CLL cases into prognostically important subsets. Subset 2 expresses a BCR with the combination of IGHV3-21-derived heavy chains (HCs) with IGLV3-21-derived light chains (LCs), and is associated with an unfavorable prognosis. Importantly, the subset 2 LC carries a single-point mutation, termed R110, at the junction between the variable and constant LC regions. By analyzing 4 independent clinical cohorts through BCR sequencing and by immunophenotyping with antibodies specifically recognizing wild-type IGLV3-21 and R110-mutated IGLV3-21 (IGLV3-21 R110 ), we show that IGLV3-21 R110 -expressing CLL represents a distinct subset with poor prognosis independent of IGHV mutations. Compared with other alleles, only IGLV3-21 * 01 facilitates effective homotypic BCR-BCR interaction that results in autonomous, oncogenic BCR signaling after acquiring R110 as a single-point mutation. Presumably, this mutation acts as a standalone driver that transforms IGLV3-21 * 01 -expressing B cells to develop CLL. Thus, we propose to expand the conventional definition of CLL subset 2 to subset 2L by including all IGLV3-21 R110 -expressing CLL cases regardless of IGHV mutational status. Moreover, the generation of monoclonal antibodies recognizing IGLV3-21 or mutated IGLV3-21 R110 facilitates the recognition of B cells carrying this mutation in CLL patients or healthy donors., Competing Interests: Competing interest statement: H.J. is a cofounder of AVA LifeScience GmbH that has filed patents on antibodies recognizing structures involved in autonomous BCR signaling., (Copyright © 2020 the Author(s). Published by PNAS.)

Intraspecific strains of Pythium aphanidermatum induced resistance in ginger against rhizome rot and activated biosynthesis of selected host proteins. Pre-inoculation of plants with IR strain (avirulent) or co-inoculation with SR2 (virulent) caused significant reduction in disease severity. Analysis of protein profiles of ginger leaves of inoculated and non-inoculated plants by SDS-PAGE and Image Master VDS-ID Gel Analysis version : 3.0 revealed that some specific defence proteins/stress proteins increased in inoculated plants. Five such proteins having molecular weight 56, 32, 27, 18 and 14 kDa were detected in leaves of plant treated with IR + SR2 strains. On the contrary, mycelial protein profiles and submerged growth of strains were studied separately and together. Mycelia of IR, SR2 and IR + SR2 exhibited 26, 23 and 25 protein bands, respectively although, 21 bands were common between IR and SR2. Growth of SR2 in synthetic medium was much higher than that of IR, but the growth of two strains together was lower than SR2 alone. To characterise strains, their differential growth response to DL-beta-aminobutyric acid (BABA), a known defence activator of ginger was also tested. Results suggested that at least 5 specific defence proteins/stress proteins were involved in microbially induced resistance in ginger and inducer strains were distinct in their specific protein profiles and sensitivity to BABA.