Metabolic gatekeeper function of B-lymphoid transcription factors.

B-lymphoid transcription factors, such as PAX5 and IKZF1, are critical for early B-cell development, yet lesions of the genes encoding these transcription factors occur in over 80% of cases of pre-B-cell acute lymphoblastic leukaemia (ALL). The importance of these lesions in ALL has, until now, remained unclear. Here, by combining studies using chromatin immunoprecipitation with sequencing and RNA sequencing, we identify a novel B-lymphoid program for transcriptional repression of glucose and energy supply. Our metabolic analyses revealed that PAX5 and IKZF1 enforce a state of chronic energy deprivation, resulting in constitutive activation of the energy-stress sensor AMPK. Dominant-negative mutants of PAX5 and IKZF1, however, relieved this glucose and energy restriction. In a transgenic pre-B ALL mouse model, the heterozygous deletion of Pax5 increased glucose uptake and ATP levels by more than 25-fold. Reconstitution of PAX5 and IKZF1 in samples from patients with pre-B ALL restored a non-permissive state and induced energy crisis and cell death. A CRISPR/Cas9-based screen of PAX5 and IKZF1 transcriptional targets identified the products of NR3C1 (encoding the glucocorticoid receptor), TXNIP (encoding a glucose-feedback sensor) and CNR2 (encoding a cannabinoid receptor) as central effectors of B-lymphoid restriction of glucose and energy supply. Notably, transport-independent lipophilic methyl-conjugates of pyruvate and tricarboxylic acid cycle metabolites bypassed the gatekeeper function of PAX5 and IKZF1 and readily enabled leukaemic transformation. Conversely, pharmacological TXNIP and CNR2 agonists and a small-molecule AMPK inhibitor strongly synergized with glucocorticoids, identifying TXNIP, CNR2 and AMPK as potential therapeutic targets. Furthermore, our results provide a mechanistic explanation for the empirical finding that glucocorticoids are effective in the treatment of B-lymphoid but not myeloid malignancies. Thus, B-lymphoid transcription factors function as metabolic gatekeepers by limiting the amount of cellular ATP to levels that are insufficient for malignant transformation

Regulation of the polymeric immunoglobulin receptor by the classical and alternative NF-κB pathways in intestinal epithelial cells

The polymeric immunoglobulin receptor (pIgR) transports IgA antibodies across intestinal epithelial cells (IECs). Expression of pIgR is upregulated by proinflammatory signaling pathways via activation of nuclear factor-κB (NF-κB). Here, we examined the contributions of the RelA-dependent classical and RelB-dependent alternative pathways of NF-κB to pIgR regulation in the HT-29 human IEC line following stimulation with tumor necrosis factor (TNF), lipopolysaccharide (LPS; Toll-like receptor 4 (TLR4) ligand), and polyinosinic: polycytidylic acid (pIC; TLR3 ligand). Whereas induction of proinflammatory genes such as interleukin-8 (IL-8) required only RelA, pIgR expression was regulated by complex mechanisms that involved both RelA and RelB. Upregulation of pIgR expression by ligation of the lymphotoxin-β receptor suggested a direct role for the alternative NF-κB pathway. Inhibition of mitogen-activated protein kinases reduced the induction of IL-8, but enhanced the induction of pIgR by TNF and TLR signaling. Regulation of pIgR through unique signaling pathways could allow IECs to sustain high levels of IgA transport while limiting the proinflammatory responses

Retinoic acid enhances the gene expression of human polymeric immunoglobulin receptor (pIgR) by TNF-α

In this study, the detailed mechanisms for the effects of vitamin A on the expression of polymeric immunoglobulin receptor (pIgR) were examined. Expression of the pIgR by tumour necrosis factor (TNF-α) was enhanced by the addition of all-trans retinoic acid (ATRA) or 9-cis retinoic acid (9CRA). This enhancement was mediated mainly by RARα, and regulated at the transcriptional level. Transcription factor nuclear factor-κB (NF-κB) binding and activation were not influenced by addition of ATRA. These data imply that RA, in combination with TNF-α, could up-regulate the expression of pIgR. In addition, we hypothesize that up-regulation of pIgR by RA is controlled through the RAR-dependent signalling pathway and that it plays a role in enhancement of mucosal immunity

Synthesis and styrene copolymerization of novel dibromo and dichloro ring-disubstituted isobutyl phenylcyanoacrylates

Novel dibromo and dichloro ring-disubstituted isobutyl phenylcyanoacrylates, RPhCH=C(CN)CO2CH2CH(CH3)2 (where R is 2,5-dibromo, 3,5-dibromo, 2,3-dichloro, 2,4-dichloro, 2,5-dichloro, 2,6-dichloro, 3,4-dichloro, 3,5-dichloro) were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and isobutyl cyanoacetate and characterized by CHN analysis, IR, 1H and 13C NMR. The acrylates were copolymerized with styrene in solution with radical initiation at 70C. The compositions of the copolymers were calculated from nitrogen analysis

Synthesis and styrene copolymerization of novel ring-monosubstituted octyl phenylcyanoacrylates

Novel ring-monosubstituted octyl phenylcyanoacrylates, RPhCH=C(CN)CO2CH2(CH2)6CH3 (where R is 2-(4-chlorophenoxy), 3-(4-methoxyphenoxy), 4-(4-methoxyphenoxy), 4-acetoxy, 4-acetamido, 4-cyano, 4-dimethylamino, 4-diethylamino, 2-bromo, 3-bromo, 2-trifluoromethyl, 3-trifluoromethyl, 4-trifluoromethyl, 3-trifluoromethoxy, 4-trifluoromethoxy) were prepared and copolymerized with styrene. The acrylates were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and octyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C NMR. All the acrylates were copolymerized with styrene in solution with radical initiation (ABCN) at 70C. The compositions of the copolymers were calculated from nitrogen analysis

Synthesis and Styrene Copolymerization of Novel Fluoro and Oxy Ring-Disubstituted Isopropyl Phenylcyanoacrylates

Novel fluoro and oxy ring-disubstituted isopropyl phenylcyanoacrylates, RPhCH=C(CN)CO2CH(CH3)2 (where R is 2-fluoro-3-methoxy, 2-fluoro-4-methoxy, 2-fluoro-5-methoxy, 2-fluoro-6-methoxy, 3-fluoro-4-methoxy, 4-fluoro-3-methoxy, 5-fluoro-2-methoxy, 4-fluoro-3-phenoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and isopropyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR, GPC, DSC, and TGA. </p