Plasticity of committed mouse B cells has been demonstrated by inactivation of the B-cell commitment transcription factor PAX5, resulting in loss of the B-cell phenotype and differentiation into various hematopoietic lineages. Furthermore, mature mouse B cells could be reprogrammed into macrophages by overexpression of myeloid-specific transcription factors. Here, we report that aberrant activity of the transmembrane receptor, Notch1, interferes with the B-lymphoid phenotype of mature human germinal center-derived B cells in Hodgkin lymphoma, so called Hodgkin and Reed-Sternberg cells. They have lost the B-cell phenotype despite their mature B-cell origin. Notch1 remodels the B-cell transcription factor network by antagonizing the key transcription factors E2A and early B-cell factor (EBF). Through this mechanism, B lineage-specific genes were suppressed and B lineage-inappropriate genes were induced. We provide evidence that absence of the Notch inhibitor Deltex1 contributes to deregulated Notch activity in Hodgkin and Reed-Sternberg cells. These data suggest that Notch activation interferes with dedifferentiation of neoplastic B cells in Hodgkin lymphoma.

Metastasis is a life-threatening feature of cancer and is primarily responsible for cancer patient mortality. Cross talk between tumor cells and endothelium is important for tumor progression and metastasis. However, very little is known about the mechanisms by which endothelial cells (ECs) that are close to tumor cells, respond to the tumor cells during tumor progression and metastasis. In this study, we exploited the use of EC-specific signal transducer activator of transcription 3 (STAT3) knockout mice to investigate the role of STAT3 in ECs in tumor progression and metastasis. We found that the loss of STAT3 in ECs did not affect primary Lewis lung carcinoma (LLC) tumor growth, but it reduced in vivo LLC metastasis in experimental and spontaneous metastasis models. Mechanistically, STAT3 activation upregulated cell adhesion molecule expression, including E-selectin and P-selectin, in murine endothelial MS-1 cells treated with tumor cell-conditioned media in vitro and in pre-metastatic lungs of tumor-bearing mice in vivo. We also found that both E-selectin and P-selectin were, at least in part, responsible for STAT3-induced adhesion and invasion of LLC cells through an EC monolayer. However, tumor cell-conditioned media from B16F10 melanoma cells did not activate STAT3 in MS-1 cells. As a result, EC STAT3 knockout did not affect B16F10 melanoma cell metastasis. In addition, various human cancer cells activated STAT3 in human ECs (HUVECs), resulting in increased cell adhesion molecule expression. Collectively, our findings demonstrate that STAT3 activation in ECs promotes tumor metastasis through the induction of cell adhesion molecules, demonstrating a role for ECs in response to tumor cells during tumor metastasis.

Summary Whole‐genome annotation error that omits essential protein‐coding genes hinders further research. We developed Target Gene Family Finder ( tgfam‐finder ), an alternative tool for the structural annotation of protein‐coding genes containing target domain(s) of interest in plant genomes. tgfam‐finder took considerably reduced annotation run‐time and improved accuracy compared to conventional annotation tools. Large‐scale re‐annotation of 50 plant genomes identified an average of 150, 166 and 86 additional far‐red‐impaired response 1, nucleotide‐binding and leucine‐rich‐repeat, and cytochrome P450 genes, respectively, that were missed in previous annotations. We detected significantly higher number of translated genes in the new annotations using mass spectrometry data from seven plant species compared to previous annotations. tgfam‐finder along with the new gene models can provide an optimized platform for comprehensive functional, comparative, and evolutionary studies in plants.

Neuron–microglia interactions have a crucial role in maintaining the neuroimmune system. The balance of neuroimmune system has emerged as an important process in the pathophysiology of depression. However, how neuron–microglia interactions contribute to major depressive disorders has been poorly understood. Herein, we demonstrated that microglia-derived synaptic changes induced antidepressive-like behavior by using microglia-specific signal transducer and activator of transcription 3 (STAT3) knockout (KO) (STAT3fl/fl;LysM-Cre+/−) mice. We found that microglia-specific STAT3 KO mice showed antidepressive-like behavior in the forced swim, tail suspension, sucrose preference, and open-field tests. Surprisingly, the secretion of macrophage colony-stimulating factor (M-CSF) was increased from neuronal cells in the brains of STAT3fl/fl;LysM-Cre+/− mice. Moreover, the phosphorylation of antidepressant-targeting mediators and brain-derived neurotrophic factor expression were increased in the brains of STAT3fl/fl;LysM-Cre+/− mice as well as in neuronal cells in response to M-CSF stimulation. Importantly, the miniature excitatory postsynaptic current frequency in the medial prefrontal cortex was increased in STAT3fl/fl;LysM-Cre+/− mice and in the M-CSF treatment group. Collectively, microglial STAT3 regulates depression-related behaviors via neuronal M-CSF-mediated synaptic activity, suggesting that inhibition of microglial STAT3 might be a new therapeutic strategy for depression.

Abstract Background Signal transducer and activator of transcription 3 (STAT3) is a latent transcription factor critical for T-cell function. Although inhibition of the Janus kinase 2 (JAK2)/STAT3 pathway has been reported to be protective against ischemia-reperfusion injury (IRI), the role of T cell–associated STAT3 in the pathogenesis of renal IRI has not been specifically defined. Methods We induced renal IRI in both mice with T cell–specific STAT3 knockout (Lck-Cre;STAT3flox/flox) and wild-type controls (C57BL/6) and assessed renal damage and inflammation at 48 h after IRI. Human proximal tubular epithelial cells grown under hypoxia were treated with a JAK2 inhibitor, caffeic acid 3,4-dihydroxy-phenylethyl ester, to determine the effect of JAK2/STAT3 inhibition on renal epithelia. Independently, we disrupted Cln 3-requiring 9 (Ctr9) to inhibit T helper 17 (Th17) activation via RNA interference and determined if Ctr9 inhibition aggravates renal injury through upregulated Th17 activation. Results The Lck-Cre;STAT3flox/flox mice exhibited significantly reduced kidney damage compared with controls. This protective effect was associated with reduced intrarenal Th17 infiltration and proinflammatory cytokines. Human proximal tubular epithelial cells under hypoxia exhibited significant upregulation of interleukin 17 receptors, and pharmacologic inhibition of JAK2 significantly ameliorated this change. RNA interference with Ctr9 in splenocytes enhanced differentiation into Th17 cells. In vivo knockdown of Ctr9 in mice with renal IRI further aggravated Th17-associated inflammation and kidney injury. Conclusions STAT3 in T cells contributes to renal IRI through Th17 activation. Inhibition of Ctr9 further enhances Th17 activation and aggravates kidney injury, further supporting the role of Th17 cells in renal IRI.