MicroRNA-21-5p as a novel therapeutic target for osteoarthritis

Abstract Objective Growing evidence indicates that microRNAs (miRNA) play a critical role in the pathogenesis of OA, and overexpressing or silencing miRNA expression in OA models can contribute to the development of miRNA-based therapeutics. The objective of this study was to determine whether intra-articular injection of miRNA can inhibit OA progression. Methods The miRNA expression profile was determined in OA cartilage tissues and controls. Functional analysis of the miRNAs on extracellular matrix degradation was performed after miRNA mimic or inhibitor transfection. Luciferase reporter assays and western blotting were employed to determine miRNA targets. To investigate the functional mechanism of miR-21-5p in OA development, miR-21-5pfl/flCol2a1-CreER and wild-type mice were subject to surgical destabilization of the medial meniscus. Therapeutically, wild-type mice undergoing surgical destabilization of the medial meniscus were treated with intra-articular injection of agomir- and antagomir-21-5p. Results We found that expression of miR-21-5p was significantly up-regulated in OA cartilage tissues. The articular cartilage degradation of miR-21-5p conditional knockout mice was significantly alleviated compared with that of wild-type mice in spontaneous and destabilization of the medial meniscus models. Through gain-of-function and loss-of-function studies, miR-21-5p was shown to significantly affect matrix synthesis genes expression, and chondrocyte proliferation and apoptosis. Further, fibroblast growth factor 18 (FGF18) was identified as a target of miR-21-5p. Intra-articular injection of antagomir-21-5p significantly attenuated the severity of experimental OA. Clinically, FGF18 expression level was correlated with miR-21-5p expression and a modified Mankin scale. Conclusion Our findings reveal a miRNA functional pathway important for OA development, highlighting miRNA-21-5p silencing as an attractive therapeutic regimen in future clinical trials involving patients with OA.

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AKT1-CREB stimulation of PDGFRα expression is pivotal for PTEN deficient tumor development

Cell Death and Disease ◽

10.1038/s41419-021-03433-0 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Xiaofeng Wan ◽

Meng Zhou ◽

Fuqiang Huang ◽

Na Zhao ◽

Xu Chen ◽

...

Keyword(s):

Signaling Pathway ◽

Human Cancer ◽

Critical Role ◽

Tumor Development ◽

Growth Factor Receptor ◽

Conditional Knockout ◽

Loss Of Function ◽

Akt Inhibitor ◽

Human Cancer Cell Lines ◽

Direct Binding

AbstractAs evidenced by the behavior of loss-of-function mutants of PTEN in the context of a gain-of-function mutation of AKT1, the PTEN-AKT1 signaling pathway plays a critical role in human cancers. In this study, we demonstrated that a deficiency in PTEN or activation of AKT1 potentiated the expression of platelet-derived growth factor receptor α (PDGFRα) based on studies on Pten−/− mouse embryonic fibroblasts, human cancer cell lines, the hepatic tissues of Pten conditional knockout mice, and human cancer tissues. Loss of PTEN enhanced PDGFRα expression via activation of the AKT1-CREB signaling cascade. CREB transactivated PDGFRα expression by direct binding of the promoter of the PDGFRα gene. Depletion of PDGFRα attenuated the tumorigenicity of Pten-null cells in nude mice. Moreover, the PI3K-AKT signaling pathway has been shown to positively correlate with PDGFRα expression in multiple cancers. Augmented PDGFRα was associated with poor survival of cancer patients. Lastly, combination treatment with the AKT inhibitor MK-2206 and the PDGFR inhibitor CP-673451 displayed synergistic anti-tumor effects. Therefore, activation of the AKT1-CREB-PDGFRα signaling pathway contributes to the tumor growth induced by PTEN deficiency and should be targeted for cancer treatment.

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MicroRNA-29a Suppresses CD36 to Ameliorate High Fat Diet-Induced Steatohepatitis and Liver Fibrosis in Mice

Cells ◽

10.3390/cells8101298 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1298 ◽

Cited By ~ 8

Author(s):

Hung-Yu Lin ◽

Feng-Sheng Wang ◽

Ya-Ling Yang ◽

Ying-Hsien Huang

Keyword(s):

Transcription Factor ◽

Liver Fibrosis ◽

High Fat Diet ◽

Critical Role ◽

Luciferase Reporter ◽

Hepatic Tissue ◽

Wild Type ◽

High Fat ◽

Alcoholic Fatty Liver ◽

Mesenchymal Transition

MicroRNA-29 (miR-29) has been shown to play a critical role in reducing inflammation and fibrosis following liver injury. Non-alcoholic fatty liver disease (NAFLD) occurs when fat is deposited (steatosis) in the liver due to causes other than excessive alcohol use and is associated with liver fibrosis. In this study, we asked whether miR-29a could reduce experimental high fat diet (HFD)-induced obesity and liver fibrosis in mice. We performed systematical expression analyses of miR-29a transgenic mice (miR-29aTg mice) and wild-type littermates subjected to HFD-induced NAFLD. The results demonstrated that increased miR-29a not only alleviated HFD-induced body weight gain but also subcutaneous, visceral, and intestinal fat accumulation and hepatocellular steatosis in mice. Furthermore, hepatic tissue in the miR-29aTg mice displayed a weak fibrotic matrix concomitant with low fibrotic collagen1α1 expression within the affected tissues compared to the wild-type (WT) mice fed the HFD diet. Increased miR-29a signaling also resulted in the downregulation of expression of the epithelial mesenchymal transition-executing transcription factor snail, mesenchymal markers vimentin, and such pro-inflammation markers as il6 and mcp1 within the liver tissue. Meanwhile, miR-29aTg-HFD mice exhibited significantly lower levels of peroxisome proliferator-activated receptor γ (PPARγ), mitochondrial transcription factor A TFAM, and mitochondria DNA content in the liver than the WT-HFD mice. An in vitro luciferase reporter assay further confirmed that miR-29a mimic transfection reduced fatty acid translocase CD36 expression in HepG2 cells. Conclusion: Our data provide new insights that miR-29a can improve HDF-induced obesity, hepatocellular steatosis, and fibrosis, as well as highlight the role of miR-29a in regulation of NAFLD.

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A Novel TWIST2-ID2 Axis That Modulates The Growth and Imatinib Sensitivity Of CML CD34+ Cells

Blood ◽

10.1182/blood.v122.21.511.511 ◽

2013 ◽

Vol 122 (21) ◽

pp. 511-511

Author(s):

Yun Zhao ◽

Wenjuan Ma ◽

Xiuyan Zhang ◽

Jiangxia Cui ◽

Ivan Sloma ◽

...

Keyword(s):

Dna Binding ◽

Progenitor Cells ◽

Lentiviral Vector ◽

Critical Role ◽

K562 Cells ◽

Luciferase Reporter ◽

Control Group ◽

Wild Type ◽

Mesenchymal Transition ◽

Cd34 Cells

Abstract TWIST is a basic helix-loop-helix transcription factor that specifies Drosophila mesoderm development. In mammals there are 2 members, TWIST1 and TWIST2. TWIST2 is a regulator of osteoblasts and muscle development and plays a critical role in the epithelial-mesenchymal transition process, as well as in cancer initiation and metastasis. Twist2-deficient mice develop a myeloproliferative disease. These findings led us to query a potential role of TWIST2 in normal and leukemic (CML) human hematopoietic cells. RT-PCR and immuno-fluorescence analysis of CD34+ bone marrow (BM) cells obtained from healthy donors demonstrated their expression of TWIST2 transcripts and protein. Lentiviral vector-mediated knockdown of TWIST2 with 2 independent shRNA sequences enhanced the erythroid and granulopoietic colony-forming activity of transduced normal BM cells ∼2-fold compared with control transduced cells (n=3, p<0.05). Interestingly, ChIP studies showed that TWIST2 can bind directly to the DNA promoter for ID2 in CD34-enriched BM cells and knockdown of TWIST2 reduced ID2 expression by 50%. In lin-CD34+ cells from 14 chronic myeloid leukemia (CML) patients, we found both TWIST2 and ID2 transcripts to be 5 and 6 fold lower than those from 6 healthy BM donors (p<0.05), with similar findings for TWIST2 and ID2 protein in the same cells. BCR-ABL1-transduced Baf/3 cells also showed a reduction in Twist2 expression. Conversely, TWIST2 expression became elevated when K562 cells were treated with Imatinib mesylate (IM). We then generated a lentiviral vector encoding TWIST2 which proved capable of inhibiting the growth of K562 and MEG-01 cells as well as CFC production from CML CD34+ cells (n=11, p<0.05). Overexpression of TWIST2 in MEG-01 cells also reduced their tumorigenic ability in subcutaneously injected nude mice (0/8 for TWIST2 group, 7/8 for control group). In addition, increased TWIST2 sensitized the IM response of K562 cells and IM-resistant CD34+ cells from CML patients (2 in chronic phase and 2 in blast crisis). Correspondingly, knockdown of TWIST2 in K562 cells enhanced their cloning efficiency by 15% and made them IM-resistant. To obtain further insight into these biological effects of TWIST2, we generated several TWIST2 mutant cDNAs, including ones with a N-terminal truncation (ΔN), a C-terminal truncation (ΔC), a F86P dimerization mutant and a b- DNA binding mutant. Analysis of the effects of these mutants when overexpressed in CML cells and cell lines showed TWIST2 dimer formation was critical for the effects obtained with wild-type TWIST2, whereas the DNA binding domain could modulate these effects but was not essential, and the N-terminal and C-terminal domains were dispensable. We also found that overexpression of TWIST2 enhanced ID2 expression in CML CD34+ cells (n=3), as well as K562 and MEG-01 cells, and ChIP analyses confirmed the binding of TWIST2 to ID2 promoter DNA from K562 and MEG-01 cells. Using ID2 promoter-driven luciferase reporter and a mutant derivative (with only the E-box sequence altered), we found that TWIST2 could activate the wild-type promoter but not the mutated one in both K562 and MEG-01 cells. Finally, we co-transduced CML cells from 3 patients with TWIST2 and shRNA against ID2 and found that this reversed the suppressed production of CFC obtained with TWIST2 alone. Similarly in K562 cells this treatment partially restored their growth rate and IM resistance. Taken together, we report a novel TWIST2-ID2 regulatory axis in normal hematopoietic progenitor cells, which can also modulate the growth and IM response of CML progenitor cells. These findings provide a baseline for the future development of more effective therapy of CML. Disclosures: No relevant conflicts of interest to declare.

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Compensatory role for Pyk2 during angiogenesis in adult mice lacking endothelial cell FAK

The Journal of Cell Biology ◽

10.1083/jcb.200710038 ◽

2008 ◽

Vol 181 (1) ◽

pp. 43-50 ◽

Cited By ~ 93

Author(s):

Sara M. Weis ◽

Ssang-Taek Lim ◽

Kimberly M. Lutu-Fuga ◽

Leo A. Barnes ◽

Xiao Lei Chen ◽

...

Keyword(s):

Blood Vessels ◽

Critical Role ◽

Conditional Knockout ◽

Compensatory Mechanism ◽

Wild Type ◽

Kinase Inhibition ◽

Pharmacological Inhibition ◽

Adult Mice ◽

Tyrosine Kinase 2 ◽

Vascular Phenotype

Focal adhesion kinase (FAK) plays a critical role during vascular development because knockout of FAK in endothelial cells (ECs) is embryonic lethal. Surprisingly, tamoxifen-inducible conditional knockout of FAK in adult blood vessels (inducible EC–specific FAK knockout [i-EC-FAK-KO]) produces no vascular phenotype, and these animals are capable of developing a robust growth factor–induced angiogenic response. Although angiogenesis in wild-type mice is suppressed by pharmacological inhibition of FAK, i-EC-FAK-KO mice are refractory to this treatment, which suggests that adult i-EC-FAK-KO mice develop a compensatory mechanism to bypass the requirement for FAK. Indeed, expression of the FAK-related proline-rich tyrosine kinase 2 (Pyk2) is elevated and phosphorylated in i-EC-FAK-KO blood vessels. In cultured ECs, FAK knockdown leads to increased Pyk2 expression and, surprisingly, FAK kinase inhibition leads to increased Pyk2 phosphorylation. Pyk2 can functionally compensate for the loss of FAK because knockdown or pharmacological inhibition of Pyk2 disrupts angiogenesis in i-EC-FAK-KO mice. These studies reveal the adaptive capacity of ECs to switch to Pyk2-dependent signaling after deletion or kinase inhibition of FAK.

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Adiponectin deficiency promotes endothelial activation and profoundly exacerbates sepsis-related mortality

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.90384.2008 ◽

2008 ◽

Vol 295 (3) ◽

pp. E658-E664 ◽

Cited By ~ 57

Author(s):

Hwee Teoh ◽

Adrian Quan ◽

K. W. Annie Bang ◽

Guilin Wang ◽

Fina Lovren ◽

...

Keyword(s):

Adhesion Molecule ◽

Critical Role ◽

Cecal Ligation ◽

Endothelial Activation ◽

Experimental Sepsis ◽

Protective Effects ◽

Loss Of Function ◽

Wild Type ◽

Endothelial Adhesion Molecule ◽

Inflammatory Models

Sepsis is a multifactorial, and often fatal, disorder typically characterized by widespread inflammation and immune activation with resultant endothelial activation. In the present study, we postulated that the adipokine adiponectin serves as a critical modulator of survival and endothelial activation in sepsis. To this aim, we evaluated both loss-of-function (adiponectin gene-deficient mice) and subsequent gain-of-function (recombinant adiponectin reconstitution) strategies in two well-established inflammatory models, cecal ligation perforation (CLP) and thioglyocollate-induced peritonitis. Adipoq−/− mice, subjected to CLP, exhibited a profound (∼8-fold) reduction in survival compared with their wild-type Adipoq+/+ littermates after 48 h. Furthermore, compared with wild-type controls, thioglycollate challenge resulted in a markedly greater influx of peritoneal neutrophils in Adipoq−/− mice accompanied by an excess production of key chemoattractant cytokines (IL-12p70, TNFα, MCP-1, and IL-6) and upregulation of aortic endothelial adhesion molecule VCAM-1 and ICAM-1 expressions. Importantly, all of these effects were blunted by recombinant total adiponectin administration given 3 days prior to thioglycollate challenge. The protective effects of adiponectin were ascribed largely to higher-order adiponectin oligomers, since administration of recombinant C39A trimeric adiponectin did not attenuate endothelial adhesion molecule expression in thioglycollate-challenged Adipoq−/− mice. These data suggest a critical role of adiponectin as a modulator of survival and endothelial inflammation in experimental sepsis and a potential mechanistic link between adiposity and increased sepsis.

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Modulation of Myeloid-Derived Dendritic Cell Maturity: Unmasking a Novel Role for the Tumor Suppressor p15Ink4b in Immunity

Blood ◽

10.1182/blood.v118.21.2469.2469 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2469-2469

Author(s):

Joanna Fares ◽

Linda Wolff ◽

Juraj Bies

Keyword(s):

T Cells ◽

Tumor Suppressor ◽

Knockout Mice ◽

Myeloid Leukemia ◽

Critical Role ◽

Conditional Knockout ◽

Maturation Process ◽

Wild Type ◽

Antigen Presenting ◽

Specific Deletion

Abstract Abstract 2469 p15Ink4b, an inhibitor of cyclin-dependent kinases, is a tumor suppressor frequently associated with hematological malignancies. Its inactivation through DNA methylation is one of the most prevalent epigenetic alterations reported in up to 80% of all acute myeloid leukemia (AML) patients. p15Ink4b is also silenced in 50% of patients diagnosed with myelodysplastic syndromes and its silencing correlates with frequent disease progression into AML. During the leukemogenesis process, escape of pre-leukemic cells from immune clearance represents an important step in the establishment of leukemic disease. Dendritic cells (DCs) are potent antigen-presenting cells that play a critical role in the regulation of immune responses. In immune surveillance, their primary function is to stimulate naïve T cells against pathogens and cancerous cells leading to their effective clearance. However, whether p15Ink4b plays a role in DC development has never been addressed. In this study, we found that expression of p15Ink4b is strongly induced in mouse splenic DCs and during the development of bone marrow-derived DCs (BM-DCs). Increased expression levels were also found during the development of human CD34-derived DCs suggesting an important role for p15Ink4b in DC maturation. To investigate the function of p15Ink4b during the differentiation and maturation of DCs we used the previously generated p15Ink4bfl/fl-LysMcre conditional knockout mice, where a myeloid-specific deletion of p15Ink4b closely mimics inactivation of the gene in AML. The knockout mice developed nonreactive monocytosis and were predisposed to retrovirus-induced AML. These results provided strong experimental evidence for a role of the gene as a tumor suppressor for myeloid leukemia. Myeloid-specific deletion of p15Ink4b in mice resulted in a reduction in the common DC progenitor pool as compared to wild type mice. p15Ink4bfl/fl-LysMcre mice had significantly fewer and less mature myeloid DCs (mDCs) than the wild type mice whereas other DC subtypes were not affected. Consistent with this data, BM cells from the p15Ink4bfl/fl-LysMcre mice cultured in vitro, generated BM-DCs that express lower levels of the antigen presenting (MHCII) and the co-stimulatory (CD80, CD86) molecules when activated with LPS. Re-expression of p15Ink4b in knockout BM-DCs resulted in an increase in the expression of both co-stimulatory molecules confirming a role for p15Ink4b in the regulation of the maturation process of DCs. The incomplete maturation of BM-DCs correlated with a reduced ability to activate T cells in a MHCII-mismatched mixed leukocyte reaction, and to uptake antigen suggesting that loss of p15Ink4b affects the function of BM-DCs. Taken together, our results indicate a novel role for p15Ink4b in mDC development, and suggest that frequent inactivation of p15Ink4b in myeloid malignancies could lead to an inefficient anti-leukemic immune response during leukemogenesis. Our data also have an important translational significance. AML blasts isolated from patients and differentiated ex-vivo into DCs represent a powerful immunotherapy tool. However, AML-DCs have reportedly a partially impaired maturation process as compared to DCs from healthy donors. We propose that re-expression of p15 in AML-DCs may overcome some of the limitations of a DC-based immunotherapy for AML patients. Disclosures: No relevant conflicts of interest to declare.

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EPEN-20. EZHIP/CATACOMB COOPERATES WITH PDGF-A AND p53 LOSS TO GENERATE A GENETICALLY ENGINEERED MOUSE MODEL FOR POSTERIOR FOSSA A EPENDYMOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa222.157 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii311-iii311

Author(s):

Emily Kagan ◽

Daniel Brat ◽

Ali Shilatifard ◽

Andrea Piunti ◽

Oren Becher

Keyword(s):

Median Survival ◽

Critical Role ◽

Pediatric Brain Tumor ◽

Genetically Engineered ◽

Rank Test ◽

Loss Of Function ◽

Wild Type ◽

Term Survival ◽

Log Rank Test ◽

Genetically Engineered Mouse Model

Abstract BACKGROUND PFA ependymoma is a pediatric brain tumor with only 30% long-term survival. Recently a gene called CXORF67/EZHIP/CATACOMB (henceforward: CATACOMB) was found to be overexpressed in PFA ependymoma. CATACOMB’s mechanism of action has been found to be analogous to that of the H3K27M mutation as its expression reduces H3K27me3 via inhibition of PRC2 catalytic activity. METHODS We infected NESTIN- or GFAP-expressing neonatal hindbrain progenitors with wild-type CATACOMB or a loss of function (LOF) point mutant (M406K), alone, with PDGFA, and with and without p53 deletion. RESULTS CATACOMB overexpression alone or with p53 loss was insufficient to induce tumorigenesis. CATACOMB overexpression with PDGFA and p53 loss was sufficient to induce tumorigenesis using either the LOF mutant (M406K) or the wild-type CATACOMB in both cells-of-origin. The histology appeared more ependymoma-like when CATACOMB was expressed in GFAP-expressing progenitors. Median survival for the model initiated in NESTIN progenitors was 99.5 days for the CATACOMB mutant (n=26) group and 61 days for the CATACOMB wild-type (n=28; log-rank test p=0.0033). Median survival for the model initiated in GFAP progenitors were 144 days for the CATACOMB mutant (n=19) group and 65 days for the CATACOMB wild-type (n=21; log-rank test is P<0.0013). Immunohistochemistry for H3K27me3 demonstrated that CATACOMB wild-type tumors had reduced H3K27me3 compared to CATACOMB mutant tumors. CONCLUSIONS Disrupting CATACOMB inhibitory activity toward PRC2 significantly increases survival in mice in both models, suggesting this activity plays a critical role in accelerating tumorigenesis. Ependymoma-like histology was more commonly observed in the model initiated in the GFAP-expressing progenitors.

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Oligodendrocyte-encoded Kir4.1 function is required for axonal integrity

eLife ◽

10.7554/elife.36428 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 28

Author(s):

Lucas Schirmer ◽

Wiebke Möbius ◽

Chao Zhao ◽

Andrés Cruz-Herranz ◽

Lucile Ben Haim ◽

...

Keyword(s):

Late Onset ◽

Critical Role ◽

Neuronal Loss ◽

Conditional Knockout ◽

Motor Deficits ◽

Loss Of Function ◽

Axonal Dysfunction ◽

Retinal Thinning

Glial support is critical for normal axon function and can become dysregulated in white matter (WM) disease. In humans, loss-of-function mutations of KCNJ10, which encodes the inward-rectifying potassium channel KIR4.1, causes seizures and progressive neurological decline. We investigated Kir4.1 functions in oligodendrocytes (OLs) during development, adulthood and after WM injury. We observed that Kir4.1 channels localized to perinodal areas and the inner myelin tongue, suggesting roles in juxta-axonal K+ removal. Conditional knockout (cKO) of OL-Kcnj10 resulted in late onset mitochondrial damage and axonal degeneration. This was accompanied by neuronal loss and neuro-axonal dysfunction in adult OL-Kcnj10 cKO mice as shown by delayed visual evoked potentials, inner retinal thinning and progressive motor deficits. Axon pathologies in OL-Kcnj10 cKO were exacerbated after WM injury in the spinal cord. Our findings point towards a critical role of OL-Kir4.1 for long-term maintenance of axonal function and integrity during adulthood and after WM injury.

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miR-541 potentiates the response of human hepatocellular carcinoma to sorafenib treatment by inhibiting autophagy

Gut ◽

10.1136/gutjnl-2019-318830 ◽

2019 ◽

Vol 69 (7) ◽

pp. 1309-1321 ◽

Cited By ~ 9

Author(s):

Wen-Ping Xu ◽

Jin-Pei Liu ◽

Ji-Feng Feng ◽

Chang-Peng Zhu ◽

Yuan Yang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Critical Role ◽

Luciferase Reporter ◽

Loss Of Function ◽

Sorafenib Treatment ◽

Transmission Electron ◽

Reporter Assays ◽

Hcc Cells

ObjectiveAutophagy participates in the progression of hepatocellular carcinoma (HCC) and the resistance of HCC cells to sorafenib. We investigated the feasibility of sensitising HCC cells to sorafenib by modulating miR-541-initiated microRNA-autophagy axis.DesignGain- and loss-of-function assays were performed to evaluate the effects of miR-541 on the malignant properties and autophagy of human HCC cells. Autophagy was quantified by western blotting of LC3, transmission electron microscopy analyses and confocal microscopy scanning of mRFP-GFP-LC3 reporter construct. Luciferase reporter assays were conducted to confirm the targets of miR-541. HCC xenograft tumours were established to analyse the role of miR-541 in sorafenib-induced lethality.ResultsThe expression of miR-541 was downregulated in human HCC tissues and was associated with malignant clinicopathologic phenotypes, recurrence and survival of patients with HCC. miR-541 inhibited the growth, metastasis and autophagy of HCC cells both in vitro and in vivo. Prediction software and luciferase reporter assays identified autophagy-related gene 2A (ATG2A) and Ras-related protein Rab-1B (RAB1B) as the direct targets of miR-541. Consistent with the effects of the miR-541 mimic, inhibition of ATG2A or RAB1B suppressed the malignant phenotypes and autophagy of HCC cells. Furthermore, siATG2A and siRAB1B partially reversed the enhancement of the malignant properties and autophagy in HCC cells mediated by the miR-541 inhibitor. More interestingly, higher miR-541 expression predicted a better response to sorafenib treatment, and the combination of miR-541 and sorafenib further suppressed the growth of HCC cells in vivo compared with the single treatment.ConclusionsDysregulation of miR-541-ATG2A/RAB1B axis plays a critical role in patients’ responses to sorafenib treatment. Manipulation of this axis might benefit survival of patients with HCC, especially in the context of the highly pursued strategies to eliminate drug resistance.

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Identification of a distant T-bet enhancer responsive to IL-12/Stat4 and IFNγ/Stat1 signals

Blood ◽

10.1182/blood-2006-11-058271 ◽

2007 ◽

Vol 110 (7) ◽

pp. 2494-2500 ◽

Cited By ~ 49

Author(s):

Yu Yang ◽

Jordi C. Ochando ◽

Jonathan S. Bromberg ◽

Yaozhong Ding

Keyword(s):

Gene Expression ◽

T Cells ◽

Reporter Gene ◽

Cd8 T Cells ◽

Critical Role ◽

Luciferase Reporter ◽

Reporter Assay ◽

Wild Type ◽

Th1 Polarization

T-bet plays a critical role in controlling IFNγ expression, Th1 polarization, and CD8 cytolytic development. Its regulation has been demonstrated to be mostly IFNγ/Stat1 dependent while IL-12/Stat4 independent. Here we show that IL-12/Stat4 binds to a distant highly conserved STAT-responsive T-bet enhancer, and induces IFNγ/Stat1-independent T-bet expression in CD8 T cells. Luciferase reporter assay showed that both Stat4 and Stat1 activate reporter gene expression from constructs containing a wild-type but not mutated T-bet enhancer. Studies in virus-infected mice demonstrated that the IL-12/Stat4/T-bet cascade operates in vivo and regulates IFNγ in CD8 T cells. Together, we provide a novel mechanism for T-bet regulation, and suggest that IL-12/Stat4/T-bet play an important role in CD8 effector responses.

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