Maternal Wnt/β-catenin signaling coactivates transcription through NF-κB binding sites during Xenopus axis formation

Determining zebrafish dorsal organizer size by a negative feedback loop between canonical/non-canonical Wnts and Tlr4/NFκB

In vertebrate embryos, the canonical Wnt ligand primes the formation of dorsal organizers that govern dorsal-ventral patterns by secreting BMP antagonists. In contrast, in Drosophila embryos, Toll-like receptor (Tlr)-mediated NFκB activation initiates dorsal-ventral patterning, wherein Wnt-mediated negative feedback regulation of Tlr/NFκB generates a BMP antagonist-secreting signalling centre to control the dorsal-ventral pattern. Although both Wnt and BMP antagonist are conserved among species, the involvement of Tlr/NFκB and feedback regulation in vertebrate organizer formation remains unclear. By imaging and genetic modification, we reveal that a negative feedback loop between canonical and non-canonical Wnts and Tlr4/NFκB determines the size of zebrafish organizer, and that Tlr/NFκB and Wnts switch initial cue and feedback mediator roles between Drosophila and zebrafish. Here, we show that canonical Wnt signalling stimulates the expression of the non-canonical Wnt5b ligand, activating the Tlr4 receptor to stimulate NFκB-mediated transcription of the Wnt antagonist frzb, restricting Wnt-dependent dorsal organizer formation.

The Transcription Factor NF-κB in Stem Cells and Development

NF-κB (nuclear factor kappa B) belongs to a family of transcription factors known to regulate a broad range of processes such as immune cell function, proliferation and cancer, neuroprotection, and long-term memory. Upcoming fields of NF-κB research include its role in stem cells and developmental processes. In the present review, we discuss one role of NF-κB in development in Drosophila, Xenopus, mice, and humans in accordance with the concept of evo-devo (evolutionary developmental biology). REL domain-containing proteins of the NF-κB family are evolutionarily conserved among these species. In addition, we summarize cellular phenotypes such as defective B- and T-cell compartments related to genetic NF-κB defects detected among different species. While NF-κB proteins are present in nearly all differentiated cell types, mouse and human embryonic stem cells do not contain NF-κB proteins, potentially due to miRNA-dependent inhibition. However, the mesodermal and neuroectodermal differentiation of mouse and human embryonic stem cells is hampered upon the repression of NF-κB. We further discuss NF-κB as a crucial regulator of differentiation in adult stem cells such as neural crest-derived and mesenchymal stem cells. In particular, c-REL seems to be important for neuronal differentiation and the neuroprotection of human adult stem cells, while RELA plays a crucial role in osteogenic and mesodermal differentiation.

Quantitative live-cell imaging and computational modeling shed new light on endogenous WNT/CTNNB1 signaling dynamics

WNT/CTNNB1 signaling regulates tissue development and homeostasis in all multicellular animals, but the underlying molecular mechanism remains incompletely understood. Specifically, quantitative insight into endogenous protein behavior is missing. Here, we combine CRISPR/Cas9-mediated genome editing and quantitative live-cell microscopy to measure the dynamics, diffusion characteristics and absolute concentrations of fluorescently tagged, endogenous CTNNB1 in human cells under both physiological and oncogenic conditions. State-of-the-art imaging reveals that a substantial fraction of CTNNB1 resides in slow-diffusing cytoplasmic complexes, irrespective of the activation status of the pathway. This cytoplasmic CTNNB1 complex undergoes a major reduction in size when WNT/CTNNB1 is (hyper)activated. Based on our biophysical measurements, we build a computational model of WNT/CTNNB1 signaling. Our integrated experimental and computational approach reveals that WNT pathway activation regulates the dynamic distribution of free and complexed CTNNB1 across different subcellular compartments through three regulatory nodes: the destruction complex, nucleocytoplasmic shuttling, and nuclear retention.

Sensing danger through a "finger"

In this issue of JEM, the study by Chen et al. (https://doi.org/10.1084/jem.20181031) reveals a previously unrecognized role of cellular nucleic acid-binding protein (Cnbp) as a novel transcriptional regulator of interleukin-12β (IL-12β) transcription and IL-12-driven, Th1-mediated immune responses, which has important implications for both host defense and inflammatory disease.

Distinctive Patterns of CTNNB1 (β-Catenin) Alterations in Salivary Gland Basal Cell Adenoma and Basal Cell Adenocarcinoma

Salivary gland basaloid neoplasms are diagnostically challenging. Limited publications report that some basal cell adenomas harbor CTNNB1 mutations, and nuclear β-catenin expression is prevalent. We evaluated β-catenin expression in basal cell adenomas and adenocarcinomas in comparison with salivary tumors in the differential diagnosis and performed targeted genetic analysis on a subset of cases. β-catenin immunohistochemistry was performed on formalin-fixed, paraffin-embedded whole sections from 73 tumors. Nuclear staining was scored semiquantitatively by extent and intensity. DNA was extracted from 6 formalin-fixed, paraffin-embedded samples (5 basal cell adenomas, 1 basal cell adenocarcinoma) for next-generation sequencing. Nuclear β-catenin staining was present in 18/22 (82%) basal cell adenomas; most were diffuse and strong and predominant in the basal component. Two of 3 basal cell adenocarcinomas were positive (1 moderate focal; 1 moderate multifocal). All adenoid cystic carcinomas (0/20) and pleomorphic adenomas (0/20) were negative; 2/8 epithelial-myoepithelial carcinomas showed focal nuclear staining. Most β-catenin-negative tumors showed diffuse membranous staining in the absence of nuclear staining. Four of 5 basal cell adenomas had exon 3 CTNNB1 mutations, all c.104T>C (p.I35T). Basal cell adenocarcinoma showed a more complex genomic profile, with activating mutations in PIK3CA, biallelic inactivation of NFKBIA, focal CYLD deletion, and without CTNNB1 mutation despite focal β-catenin expression. Nuclear β-catenin expression has moderate sensitivity (82%) for basal cell adenoma but high specificity (96%) in comparison with its morphologic mimics. CTNNB1 mutation was confirmed in most basal cell adenomas tested, and findings in basal cell adenocarcinoma suggest possible tumorigenic mechanisms, including alterations in PI3K and NF-κB pathways and transcriptional regulation.

Glycogen synthase kinase-3 beta (GSK-3β) signaling: Implications for Parkinson's disease

Glycogen synthase kinase 3 (GSK-3) dysregulation plays an important role in the pathogenesis of numerous disorders, affecting the central nervous system (CNS) encompassing both neuroinflammation and neurodegenerative diseases. Several lines of evidence have illustrated a key role of the GSK-3 and its cellular and molecular signaling cascades in the control of neuroinflammation. Glycogen synthase kinase 3 beta (GSK-3β), one of the GSK-3 isomers, plays a major role in neuronal apoptosis and its inhibition decreases expression of alpha-Synuclein (α-Synuclein), which make this kinase an attractive therapeutic target for neurodegenerative disorders. Parkinson's disease (PD) is a chronic neurodegenerative movement disorder characterized by the progressive and massive loss of dopaminergic neurons by neuronal apoptosis in the substantia nigra pars compacta and depletion of dopamine in the striatum, which lead to pathological and clinical abnormalities. Thus, understanding the role of GSK-3β in PD will enhance our knowledge of the basic mechanisms underlying the pathogenesis of this disorder and facilitate the identification of new therapeutic avenues. In recent years, GSK-3β has been shown to play essential roles in modulating a variety of cellular functions, which have prompted efforts to develop GSK-3β inhibitors as therapeutics. In this review, we summarize GSK-3 signaling pathways and its association with neuroinflammation. Moreover, we highlight the interaction between GSK-3β and several cellular processes involved in the pathogenesis of PD, including the accumulation of α-Synuclein aggregates, oxidative stress and mitochondrial dysfunction. Finally, we discuss about GSK-3β inhibitors as a potential therapeutic strategy in PD.

Overexpression of Wild-Type p53-Induced Phosphatase 1 Confers Poor Prognosis of Patients with Nasopharyngeal Carcinoma

This study aimed to analyze the expression, clinical significance of proto-oncogene in nasopharyngeal carcinoma and the biological effect in its cell line by siRNA targeting wild-type p53-induced phosphatase 1 (Wip1). Immunohistochemistry and western blot were respectively used to analyze Wip1 protein expression in 85 cases of nasopharyngeal cancer and normal tissues to study the relationship between Wip1 expression and clinical factors. Wip1 siRNA was transiently transfected into papillary nasopharyngeal carcinoma cell by liposome-mediated method and was detected by Quantitative real-time RT-PCR (qRT-PCR) and western blot. MTT assay, cell apoptosis, migration and invasion were also conducted as to the influence of the down-regulated expression of Wip1 that might be found on CNE2 cells biological effect. The level of Wip1 protein expression was found to be significantly higher in nasopharyngeal cancer tissue than normal tissues (P <0.05). There were significant differences between Wip1 expression and T stages, lymph node metastasis, clinical stages, tumor differentiation and radiotherapy response (P < 0.05), regardless of age, gender (P > 0.05). Meanwhile, Increased expression of Wip1 was significantly with poor overall survival time by Kaplan-Meier analysis (P < 0.05). Wip1 expression deletion determines independent risk factors for prognosis of patients with nasopharyngeal carcinoma in addition to tumor T stage, clinical stage, histological grade and lymph node metastasis outside by Cox-2 in the regression analysis (P < 0.05). qRT-PCR and Western blot showed that CNE2 cell transfected Wip1 siRNA had a lower relative expressive content than normal cell (P < 0.05). MTT assay, cell apoptosis, cell cycles demonstrated that CNE2 cell transfected Wip1 siRNA had a lower survival fraction, higher cell apoptosis, more percentage of the G0/G1 phases, significant decrease in migration and invasion, and higher P53 and P16 protein expression compared with CNE2 cell untransfected Wip1 siRNA (P < 0.05). Wip1 protein was increased in nasopharyngeal carcinoma, specifically in T stages, lymph node metastasis, clinical stages and tumor differentiation. Wip1 may involved in the biological processes of nasopharyngeal cancer cell proliferation, apoptosis, and migration and invasion by regulation P53 and P16 protein expression.

Expression of Wip1 in kidney carcinoma and its correlation with tumor metastasis and clinical significance

This study aimed to analyze the expression, clinical significance of proto-oncogene in kidney carcinoma and the biological effect in its cell line by siRNA targeting wild-type p53-induced phosphatase 1 (Wip1). Immunohistochemistry and western blot were respectively used to analyze Wip1 protein expression in 78 cases of kidney cancer and normal tissues to study the relationship between Wip1 expression and clinical factors. Wip1 siRNA was transiently transfected into papillary kidney carcinoma cell by liposome-mediated method and was detected by Quantitative real-time RT-PCR (qRT-PCR) and western blot. MTT assay, cell apoptosis, cell migration and invasion were also conducted as to the influence of the down-regulated expression of Wip1 that might be found on ACHN cells biological effect. The level of Wip1 protein expression was found to be significantly higher in kidney cancer tissue than normal tissues (P < 0.05). There were significant differences between Wip1 expression and lymph node metastasis, clinical stages and tumor differentiation (P < 0.05). Meanwhile, Increased expression of Wip1 was significantly with poor overall survival time by Kaplan-Meier analysis (P < 0.05). qRT-PCR and Western blot showed that ACHN cell transfected Wip1 siRNA had a lower relative expressive content than normal cell (P < 0.05). MTT assay, cell apoptosis, cell cycles demonstrated that ACHN cell transfected Wip1 siRNA had a lower survival fraction, higher cell apoptosis, more percentage of the G0/G1 phases, significant decrease in migration and invasion, and higher P53 and P16 protein expression compared with ACHN cell untransfected Wip1 siRNA (P < 0.05). Wip1 protein was increased in kidney carcinoma, specifically in T stages, lymph node metastasis, clinical stages and tumor differentiation. Wip1 may involved in the biological processes of kidney cancer cell proliferation, apoptosis, and migration and invasion by regulation P53 and P16 protein expression.

Looking beyond the Wnt pathway for the deep nature of β-catenin

After two decades of stardom, one would think that β-catenin has revealed all of its most intimate details. Yet the essence of its duality has remained mysterious--how can a single protein both be the core link between cadherins and the cytoskeleton, and the nuclear messenger for Wnt signalling? On the basis of the available evidence and on molecular and evolutionary considerations, I propose that β-catenin was a born nuclear transport receptor, which by interacting with adhesion molecules acquired the property to coordinate nuclear functions with cell-cell adhesion. While Wnt signalling diverted this activity, the original pathway might still function in modern eukaryotes.