scholarly journals Consistent activation of the β-catenin pathway by Salmonella type-three secretion effector protein AvrA in chronically infected intestine

2012 ◽  
Vol 303 (10) ◽  
pp. G1113-G1125 ◽  
Author(s):  
Rong Lu ◽  
Xingyin Liu ◽  
Shaoping Wu ◽  
Yinglin Xia ◽  
Yong-guo Zhang ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
Posttranslational Modifications ◽  
Target Genes ◽  
Intestinal Inflammation ◽  
Public Health Problem ◽  
Salmonella Infection ◽  
Risk Of Cancer ◽  
Type Three Secretion

Salmonella infection is a common public health problem that can become chronic and increase the risk of cancer. Live, mutated Salmonella is used to target cancer cells. However, few studies have addressed chronic Salmonella infection in vivo. AvrA is a Salmonella type-three secretion effector that is multifunctional, inhibiting intestinal inflammation and enhancing proliferation. β-catenin is a key player in intestinal renewal, inflammation, and tumorigenesis. We hypothesize that in Salmonella -infected intestine, AvrA chronically activates the β-catenin pathway and increases cell proliferation, thus deregulating the intestinal responses to bacterial infection. We followed mice with Salmonella infection for 27 wk and investigated the physiological effects and role of AvrA on β-catenin in chronically infected intestine. We found that AvrA persistently regulated β-catenin posttranslational modifications, including phosphorylation and acetylation. Moreover, the upstream regulator Akt, transcription factors, T cell factors, nuclear β-catenin, and β-catenin target genes were enhanced in mice infected with Salmonella -expressing AvrA. AvrA has a chronic functional role in promoting intestinal renewal. In summary, we have uncovered an essential role of Salmonella AvrA in chronically activating β-catenin and impacting intestinal renewal in small intestine and colon. Our study emphasizes the importance of AvrA in chronic bacterial infection.

scholarly journals NUSAP1 Promotes Gastric Cancer Progression Through Regulation of Yap Stability

2020 ◽  
Author(s):  
Hui Guo ◽  
Jianping Zou ◽  
Ling Zhou ◽  
Yan He ◽  
Miao Feng ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Progression ◽  
Target Genes ◽  
Hippo Pathway ◽  
Critical Role ◽  
Xenograft Model ◽  
Migration And Invasion

Abstract Background:Nucleolar and spindle associated protein (NUSAP1) is involved in tumor initiation, progression and metastasis. However, there are limited studies regarding the role of NUSAP1 in gastric cancer (GC). Methods: The expression profile and clinical significance of NUSAP1 in GC were analysed in online database using GEPIA, Oncomine and KM plotter, which was further confirmed in clinical specimens.The functional role of NUSAP1 were detected utilizing in vitro and in vivo assays. Western blotting, qRT-PCR, the cycloheximide-chase, immunofluorescence staining and Co-immunoprecipitaion (Co-IP) assays were performed to explore the possible molecular mechanism by which NUSAP1 stabilizes YAP protein. Results:In this study, we found that the expression of NUSAP1 was upregulated in GC tissues and correlates closely with progression and prognosis. Additionally, abnormal NUSAP1 expression promoted malignant behaviors of GC cells in vitro and in a xenograft model. Mechanistically, we discovered that NUSAP1 physically interacts with YAP and furthermore stabilizes YAP protein expression, which induces the transcription of Hippo pathway downstream target genes. Furthermore, the effects of NUSAP1 on GC cell growth, migration and invasion were mainly mediated by YAP. Conclusions:Our data demonstrates that the novel NUSAP1-YAP axis exerts an critical role in GC tumorigenesis and progression, and therefore could provide a novel therapeutic target for GC treatment.

scholarly journals Histone H3K23-specific acetylation by MORF is coupled to H3K14 acylation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Brianna J. Klein ◽  
Suk Min Jang ◽  
Catherine Lachance ◽  
Wenyi Mi ◽  
Jie Lyu ◽  
...  
Keyword(s):  
Posttranslational Modification ◽  
Memory Impairment ◽  
Target Genes ◽  
Epigenetic Mark ◽  
Mechanistic Insight ◽  
Genomic Analyses ◽  
Insight Into

Abstract Acetylation of histone H3K23 has emerged as an essential posttranslational modification associated with cancer and learning and memory impairment, yet our understanding of this epigenetic mark remains insufficient. Here, we identify the native MORF complex as a histone H3K23-specific acetyltransferase and elucidate its mechanism of action. The acetyltransferase function of the catalytic MORF subunit is positively regulated by the DPF domain of MORF (MORFDPF). The crystal structure of MORFDPF in complex with crotonylated H3K14 peptide provides mechanistic insight into selectivity of this epigenetic reader and its ability to recognize both histone and DNA. ChIP data reveal the role of MORFDPF in MORF-dependent H3K23 acetylation of target genes. Mass spectrometry, biochemical and genomic analyses show co-existence of the H3K23ac and H3K14ac modifications in vitro and co-occupancy of the MORF complex, H3K23ac, and H3K14ac at specific loci in vivo. Our findings suggest a model in which interaction of MORFDPF with acylated H3K14 promotes acetylation of H3K23 by the native MORF complex to activate transcription.

scholarly journals Transgenic Analysis Reveals that Thyroid Hormone Receptor Is Sufficient To Mediate the Thyroid Hormone Signal in Frog Metamorphosis

2004 ◽  
Vol 24 (20) ◽  
pp. 9026-9037 ◽  
Author(s):  
Daniel R. Buchholz ◽  
Akihiro Tomita ◽  
Liezhen Fu ◽  
Bindu D. Paul ◽  
Yun-Bo Shi
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Target Genes ◽  
Thyroid Hormone Receptor ◽  
Gene Activation ◽  
Inducible Promoter ◽  
Vertebrate Development ◽  
Transcription System

ABSTRACT Thyroid hormone (T3) has long been known to be important for vertebrate development and adult organ function. Whereas thyroid hormone receptor (TR) knockout and transgenic studies of mice have implicated TR involvement in mammalian development, the underlying molecular bases for the resulting phenotypes remain to be determined in vivo, especially considering that T3 is known to have both genomic, i.e., through TRs, and nongenomic effects on cells. Amphibian metamorphosis is an excellent model for studying the role of TR in vertebrate development because of its total dependence on T3. Here we investigated the role of TR in metamorphosis by developing a dominant positive mutant thyroid hormone receptor (dpTR). In the frog oocyte transcription system, dpTR bound a T3-responsive promoter and activated the promoter independently of T3. Transgenic expression of dpTR under the control of a heat shock-inducible promoter in premetamorphic tadpoles led to precocious metamorphic transformations. Molecular analyses showed that dpTR induced metamorphosis by specifically binding to known T3 target genes, leading to increased local histone acetylation and gene activation, similar to T3-bound TR during natural metamorphosis. Our experiments indicated that the metamorphic role of T3 is through genomic action of the hormone, at least on the developmental parameters tested. They further provide the first example where TR is shown to mediate directly and sufficiently these developmental effects of T3 in individual organs by regulating target gene expression in these organs.

scholarly journals GnRH Receptor Expression and Reproductive Function Depend on JUN in GnRH Receptor‒Expressing Cells

Endocrinology ◽  
2018 ◽  
Vol 159 (3) ◽  
pp. 1496-1510 ◽  
Author(s):  
Carrie R Jonak ◽  
Nancy M Lainez ◽  
Ulrich Boehm ◽  
Djurdjica Coss
Keyword(s):  
Target Genes ◽  
Reproductive Function ◽  
Gnrh Receptor ◽  
Receptor Expression ◽  
Specific Expression ◽  
Α Subunit ◽  
Estrous Cycles ◽  
Hormone Synthesis

Abstract Gonadotropin-releasing hormone (GnRH) from the hypothalamus regulates synthesis and secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gonadotropes. LH and FSH are heterodimers composed of a common α-subunit and unique β-subunits, which provide biological specificity and are limiting components of mature hormone synthesis. Gonadotrope cells respond to GnRH via specific expression of the GnRH receptor (Gnrhr). GnRH induces the expression of gonadotropin genes and of the Gnrhr by activation of specific transcription factors. The JUN (c-Jun) transcription factor binds to AP-1 sites in the promoters of target genes and mediates induction of the FSHβ gene and of the Gnrhr in gonadotrope-derived cell lines. To analyze the role of JUN in reproductive function in vivo, we generated a mouse model that lacks JUN specifically in GnRH receptor‒expressing cells (conditional JUN knockout; JUN-cKO). JUN-cKO mice displayed profound reproductive anomalies such as reduced LH levels resulting in lower gonadal steroid levels, longer estrous cycles in females, and diminished sperm numbers in males. Unexpectedly, FSH levels were unchanged in these animals, whereas Gnrhr expression in the pituitary was reduced. Steroidogenic enzyme expression was reduced in the gonads of JUN-cKO mice, likely as a consequence of reduced LH levels. GnRH receptor‒driven Cre activity was detected in the hypothalamus but not in the GnRH neuron. Female, but not male, JUN-cKO mice exhibited reduced GnRH expression. Taken together, our results demonstrate that GnRH receptor‒expression levels depend on JUN and are critical for reproductive function.

scholarly journals Nrf Transcription Factors in Keratinocytes Are Essential for Skin Tumor Prevention but Not for Wound Healing

2006 ◽  
Vol 26 (10) ◽  
pp. 3773-3784 ◽  
Author(s):  
Ulrich auf dem Keller ◽  
Marcel Huber ◽  
Tobias A. Beyer ◽  
Angelika Kümin ◽  
Christina Siemes ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Wound Repair ◽  
Target Genes ◽  
Dominant Negative ◽  
Skin Tumor ◽  
Cellular Stress Response ◽  
Skin Development

ABSTRACT The Nrf2 transcription factor is a key player in the cellular stress response through its regulation of cytoprotective genes. In this study we determined the role of Nrf2-mediated gene expression in keratinocytes for skin development, wound repair, and skin carcinogenesis. To overcome compensation by the related Nrf1 and Nrf3 proteins, we expressed a dominant-negative Nrf2 mutant (dnNrf2) in the epidermis of transgenic mice. The functionality of the transgene product was verified in vivo using mice doubly transgenic for dnNrf2 and an Nrf2-responsive reporter gene. Surprisingly, no abnormalities of the epidermis were observed in dnNrf2-transgenic mice, and even full-thickness skin wounds healed normally. However, the onset, incidence, and multiplicity of chemically induced skin papillomas were strikingly enhanced, whereas the progression to squamous cell carcinomas was unaltered. We provide evidence that the enhanced tumorigenesis results from reduced basal expression of cytoprotective Nrf target genes, leading to accumulation of oxidative damage and reduced carcinogen detoxification. Our results reveal a crucial role of Nrf-mediated gene expression in keratinocytes in the prevention of skin tumors and suggest that activation of Nrf2 in keratinocytes is a promising strategy to prevent carcinogenesis of this highly exposed organ.

scholarly journals IL-27 promotes T cell–dependent colitis through multiple mechanisms

2010 ◽  
Vol 208 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Jennifer H. Cox ◽  
Noelyn M. Kljavin ◽  
Nandhini Ramamoorthi ◽  
Lauri Diehl ◽  
Marcel Batten ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Intestinal Inflammation ◽  
Interferon Γ ◽  
Transfer Model ◽  
Proinflammatory Role ◽  
Immune Pathology

Interleukin-27 (IL-27) is a cytokine known to have both proinflammatory and immunoregulatory functions. The latter appear to dominate in vivo, where IL-27 suppresses TH17 responses and promotes the differentiation of Tr1 cells expressing interferon-γ and IL-10 and lacking forkhead box P3 (Foxp3). Accordingly, IL-27 receptor α (Il27ra)–deficient mice suffer from exacerbated immune pathology when infected with various parasites or challenged with autoantigens. Because the role of IL-27 in human and experimental mouse colitis is controversial, we studied the consequences of Il27ra deletion in the mouse T cell transfer model of colitis and unexpectedly discovered a proinflammatory role of IL-27. Absence of Il27ra on transferred T cells resulted in diminished weight loss and reduced colonic inflammation. A greater fraction of transferred T cells assumed a Foxp3+ phenotype in the absence of Il27ra, suggesting that IL-27 functions to restrain regulatory T cell (Treg) development. Indeed, IL-27 suppressed Foxp3 induction in vitro and in an ovalbumin-dependent tolerization model in vivo. Furthermore, effector cell proliferation and IFN-γ production were reduced in the absence of Il27ra. Collectively, we describe a proinflammatory role of IL-27 in T cell–dependent intestinal inflammation and provide a rationale for targeting this cytokine in pathological situations that result from a breakdown in peripheral immune tolerance.

scholarly journals Flow-dependent YAP/TAZ activities regulate endothelial phenotypes and atherosclerosis

2016 ◽  
Vol 113 (41) ◽  
pp. 11525-11530 ◽  
Author(s):  
Kuei-Chun Wang ◽  
Yi-Ting Yeh ◽  
Phu Nguyen ◽  
Elaine Limqueco ◽  
Jocelyn Lopez ◽  
...  
Keyword(s):  
Target Genes ◽  
Critical Role ◽  
Atherosclerotic Lesion ◽  
Tissue Growth ◽  
Binding Motif ◽  
Disturbed Flow ◽  
Atherosclerotic Lesions ◽  
En Face

The focal nature of atherosclerotic lesions suggests an important role of local hemodynamic environment. Recent studies have demonstrated significant roles of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) in mediating mechanotransduction and vascular homeostasis. The objective of this study is to investigate the functional role of YAP/TAZ in the flow regulation of atheroprone endothelial phenotypes and the consequential development of atherosclerotic lesions. We found that exposure of cultured endothelial cells (ECs) to the atheroprone disturbed flow resulted in YAP/TAZ activation and translocation into EC nucleus to up-regulate the target genes, including cysteine-rich angiogenic inducer 61 (CYR61), connective tissue growth factor (CTGF), and ankyrin repeat domain 1 (ANKRD1). In contrast, the athero-protective laminar flow suppressed YAP/TAZ activities. En face analysis of mouse arteries demonstrated an increased nuclear localization of YAP/TAZ and elevated levels of the target genes in the endothelium in atheroprone areas compared with athero-protective areas. YAP/TAZ knockdown significantly attenuated the disturbed flow induction of EC proliferative and proinflammatory phenotypes, whereas overexpression of constitutively active YAP was sufficient to promote EC proliferation and inflammation. In addition, treatment with statin, an antiatherosclerotic drug, inhibited YAP/TAZ activities to diminish the disturbed flow-induced proliferation and inflammation. In vivo blockade of YAP/TAZ translation by morpholino oligos significantly reduced endothelial inflammation and the size of atherosclerotic lesions. Our results demonstrate a critical role of the activation of YAP/TAZ by disturbed flow in promoting atheroprone phenotypes and atherosclerotic lesion development. Therefore, inhibition of YAP/TAZ activation is a promising athero-protective therapeutic strategy.

scholarly journals Activation of the Hypoxia-Inducible Factor Pathway Expands Early Thymic Progenitors

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2896-2896
Author(s):  
Anita Hollenbeck ◽  
Stefanie Weber ◽  
Kathrin Händschke ◽  
Mandy Necke ◽  
Bertram Opalka ◽  
...  
Keyword(s):  
Cellular Response ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Cell Receptor ◽  
Normal Numbers ◽  
Cellular Compartment ◽  
Vhl Gene ◽  
Von Hippel Lindau

Abstract Early thymic progenitors enter the thymus and are exposed to regional hypoxia while they develop in a step-wise manner to mature functional T-cells. Therefore, hypoxia might represent an important component of the highly specialized thymic microenvironment. On the molecular level the hypoxia-inducible factor pathway controls the cellular response to hypoxia. In this pathway, the von-Hippel-Lindau protein (pVHL) continuously mediates the destruction of the transcription factor hypoxia-inducible factor-1α (HIF-1α) under normoxic conditions. Under hypoxia HIF-1α degradation is inhibited leading to the activation of HIF-1α target genes. Others used lck-Cre transgene-mediated conditional in vivo deletion of the Vhl gene to study the role of the oxygen-sensing pathway in developing thymocytes and found normal numbers of early double-negative (DN; CD4-CD8-) thymocytes (Biju et al., Mol Cell Biol, 2004). However, lck-Cre deletion initiates at the DN3 (CD25+CD44-) stage leaving the Vhl locus of very early DN1 (CD25-CD44+), DN2 (CD25+CD44+) and DN3 thymocytes unaltered. Therefore, we here used the ubiquitous hematopoietic deleter strain vav-Cre to investigate the role of pVHL in very early thymocytes (vav-Cre;VhlloxP;loxP mice). Using a PCR-based strategy we confirmed complete deletion of the Vhl gene in this model. We observed unaltered DN1 and DN2 progenitor numbers, however in contrast to the published lck-cre-mediated system we consistently observed an up to twofold expansion of the DN3 cellular compartment. As the hypoxia-inducible factor pathway was shown to modulate NOTCH1 signaling we studied Notch1 expression on Vhl-deficient thymocytes. Strikingly, Notch1 expression was significantly increased on expanded Vhl null DN3 thymocytes. At the DN3 developmental stage selection of cells with an accurately re-arranged T-cell receptor β-locus occurs. Thus, we analyzed pre- and post-β-selection DN3 cells by CD28 staining. Interestingly, we found both pre- and post-β-selection DN3 subpopulations expanded. In order to investigate whether the progenitor expansion is mediated by the lack of HIF-1α inhibition in the Vhl-deficient context we studied DN3 thymocytes in a conditional hematopoietic HIF-1α gain-of-function model (vav-Cre;HIF1dPA). Overexpression of HIF-1α, which is insensitive to pVHL-mediated degradation in vav-Cre;HIF1dPAmice, also resulted in expanded DN3 thymocytes. In summary, we describe novel conditional models to genetically alter the hypoxia-inducible factor pathway within very early thymic progenitors. Genetic Vhl loss led to an expansion of DN3 thymocytes. This DN3 expansion is most likely due to the absence of HIF-1α-inhibition, because HIF-1α overexpression phenocopied the Vhl-deficient DN3 thymocyte expansion. Disclosures Dührsen: Celgene: Honoraria, Research Funding.

scholarly journals EZH1/2 inhibition augments the anti-tumor effects of sorafenib in hepatocellular carcinoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuko Kusakabe ◽  
Tetsuhiro Chiba ◽  
Motohiko Oshima ◽  
Shuhei Koide ◽  
Ola Rizq ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Growth ◽  
Target Genes ◽  
Antitumor Effects ◽  
Sorafenib Treatment ◽  
Ezh2 Expression ◽  
Combined Use

AbstractBoth EZH2 and its homolog EZH1 function as histone H3 Lysine 27 (H3K27) methyltransferases and repress the transcription of target genes. Dysregulation of H3K27 trimethylation (H3K27me3) plays an important role in the development and progression of cancers such as hepatocellular carcinoma (HCC). This study investigated the relationship between the expression of EZH1/2 and the level of H3K27me3 in HCC. Additionally, the role of EZH1/2 in cell growth, tumorigenicity, and resistance to sorafenib were also analyzed. Both the lentiviral knockdown and the pharmacological inhibition of EZH1/2 (UNC1999) diminished the level of H3K27me3 and suppressed cell growth in liver cancer cells, compared with EZH1 or EZH2 single knockdown. Although a significant association was observed between EZH2 expression and H3K27me3 levels in HCC samples, overexpression of EZH1 appeared to contribute to enhanced H3K27me3 levels in some EZH2lowH3K27me3high cases. Akt suppression following sorafenib treatment resulted in an increase of the H3K27me3 levels through a decrease in EZH2 phosphorylation at serine 21. The combined use of sorafenib and UNC1999 exhibited synergistic antitumor effects in vitro and in vivo. Combination treatment canceled the sorafenib-induced enhancement in H3K27me3 levels, indicating that activation of EZH2 function is one of the mechanisms of sorafenib-resistance in HCC. In conclusion, sorafenib plus EZH1/2 inhibitors may comprise a novel therapeutic approach in HCC.

scholarly journals High-Fat Diet Promotes DSS-Induced Ulcerative Colitis by Downregulated FXR Expression through the TGFB Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Di Zhao ◽  
Chenwen Cai ◽  
Qiyi Chen ◽  
Shuang Jin ◽  
Bo Yang ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
High Fat Diet ◽  
Target Genes ◽  
Intestinal Inflammation ◽  
Farnesoid X Receptor ◽  
Mucosal Barrier ◽  
High Fat ◽  
Colon Rectal Cancer ◽  
Chronic Intestinal Inflammation

Ulcerative colitis is one of the IBD which cause a chronic intestinal inflammation and dysfunctional of the mucosal barrier. For now, the incident of UC was steadily increased all over the world. It has become a novel independent risk factor of several severe diseases especially colon-rectal cancer. However, the etiology of UC was still obscure. Previous studies show that high-fat diet contributed to the pathogenesis of immune system dysregulation, and farnesoid X receptor (FXR) was also implicated in the pathogenesis of various inflammatory symptoms. Yet, their inner roles in the pathogenesis of UC have not been mentioned. In this study, we aim to investigate the role of FXR in UC. High-fat diet (HFD) promotes the progression of DSS-induced UC, shows an increasing secretion of bile acid in serum, and leads to a downregulation of FXR target genes (FXRα, Shp, and lbabp). Adding FXR agonist FexD rescues the phenotype induced by high-fat diet, whereas TGFBRI inhibitor SB431542 abrogates the restoration by FexD in DSS-induced UC mice. To further verify the relationship between the FXR and TGFB signaling pathway, we made a UC-HFD model in the Caco2 cell line. Results shows the same conclusion that FXR mitigate UC inflammation through a TGFB-dependent pathway. These results expand the role of FXR in ulcerative colitis and suggest that FXR activation may be considered a therapeutic strategy for UC.

Sign in / Sign up

Export Citation Format

Share Document