T helper 17 (Th17) cell plasticity contributes to both immunity and autoimmunity; however, the factors that control lineage flexibility are mostly unknown. Here we show the activator protein-1 (AP-1) ...factor JunB is an essential regulator of Th17 cell identity. JunB activates expression of Th17 lineage-specifying genes and coordinately represses genes controlling Th1 and regulatory T-cell fate. JunB supports Th17 cell identity by regulating key AP-1 complex constituents. In particular, JunB limits the expression of the subset repressor IRF8, and impedes access of JunD to regulatory regions of alternative effector loci. Although dispensable for homeostatic Th17 cell development, JunB is required for induction and maintenance of Th17 effector responses in the inflammatory contexts of both acute infection and chronic autoimmunity in mice. Through regulatory network analysis, we show that JunB is a core regulator of global transcriptional programs that promote Th17 cell identity and restrict alternative CD4
T-cell potential.AP-1 family transcription factors regulate CD4
T helper cell differentiation. Here the authors show that the AP-1 member JunB is a nonredundant regulator of transcriptional programs that support Th17 cell identity and restrain alternative Th1 and Treg cell fates in inflammatory contexts of acute fungal infection and chronic autoimmunity.
Fibroblast growth factor receptor (FGFR) 2 gene alterations are involved in the pathogenesis of cholangiocarcinoma. Pemigatinib is a selective, potent, oral inhibitor of FGFR1, 2, and 3. This study ...evaluated the safety and antitumour activity of pemigatinib in patients with previously treated, locally advanced or metastatic cholangiocarcinoma with and without FGFR2 fusions or rearrangements.
In this multicentre, open-label, single-arm, multicohort, phase 2 study (FIGHT-202), patients aged 18 years or older with disease progression following at least one previous treatment and an Eastern Cooperative Oncology Group (ECOG) performance status of 0–2 recruited from 146 academic or community-based sites in the USA, Europe, the Middle East, and Asia were assigned to one of three cohorts: patients with FGFR2 fusions or rearrangements, patients with other FGF/FGFR alterations, or patients with no FGF/FGFR alterations. All enrolled patients received a starting dose of 13·5 mg oral pemigatinib once daily (21-day cycle; 2 weeks on, 1 week off) until disease progression, unacceptable toxicity, withdrawal of consent, or physician decision. The primary endpoint was the proportion of patients who achieved an objective response among those with FGFR2 fusions or rearrangements, assessed centrally in all patients who received at least one dose of pemigatinib. This study is registered with ClinicalTrials.gov, NCT02924376, and enrolment is completed.
Between Jan 17, 2017, and March 22, 2019, 146 patients were enrolled: 107 with FGFR2 fusions or rearrangements, 20 with other FGF/FGFR alterations, 18 with no FGF/FGFR alterations, and one with an undetermined FGF/FGFR alteration. The median follow-up was 17·8 months (IQR 11·6–21·3). 38 (35·5% 95% CI 26·5–45·4) patients with FGFR2 fusions or rearrangements achieved an objective response (three complete responses and 35 partial responses). Overall, hyperphosphataemia was the most common all-grade adverse event irrespective of cause (88 60% of 146 patients). 93 (64%) patients had a grade 3 or worse adverse event (irrespective of cause); the most frequent were hypophosphataemia (18 12%), arthralgia (nine 6%), stomatitis (eight 5%), hyponatraemia (eight 5%), abdominal pain (seven 5%), and fatigue (seven 5%). 65 (45%) patients had serious adverse events; the most frequent were abdominal pain (seven 5%), pyrexia (seven 5%), cholangitis (five 3%), and pleural effusion (five 3%). Overall, 71 (49%) patients died during the study, most frequently because of disease progression (61 42%); no deaths were deemed to be treatment related.
These data support the therapeutic potential of pemigatinib in previously treated patients with cholangiocarcinoma who have FGFR2 fusions or rearrangements.
Incyte Corporation.
During embryogenesis, basic fibroblast growth factor (bFGF) is released from neural tube and myotome to promote myogenic fate in the somite, and is routinely used for the culture of adult skeletal ...muscle (SKM) stem cells (MuSC, called satellite cells). However, the mechanism employed by bFGF to promote SKM lineage and MuSC proliferation has not been analyzed in detail. Furthermore, the question of if the post-translational modification (PTM) of bFGF is important to its stemness-promoting effect has not been answered. In this study, GST-bFGF was expressed and purified from
, which lacks the PTM system in eukaryotes. We found that both GST-bFGF and commercially available bFGF activated the Akt-Erk pathway and had strong cell proliferation effect on C2C12 myoblasts and MuSC. GST-bFGF reversibly compromised the myogenesis of C2C12 myoblasts and MuSC, and it increased the expression of
,
, and
but strongly repressed that of
, suggesting the maintenance of myogenic stemness amid repressed
expression. The proliferation effect of GST-bFGF was conserved in C2C12 over-expressed with
(C2C12-tTA-MyoD), implying its independence of the down-regulation of
. In addition, the repressive effect of GST-bFGF on myogenic differentiation was almost totally rescued by the over-expression of
. Together, these evidences suggest that (1) GST-bFGF and bFGF have similar effects on myogenic cell proliferation and differentiation, and (2) GST-bFGF can promote MuSC stemness and proliferation by differentially regulating
and Pax3/7, (3) MyoD repression by GST-bFGF is reversible and independent of the proliferation effect, and (4) GST-bFGF can be a good substitute for bFGF in sustaining MuSC stemness and proliferation.
Fibroblast growth factor receptor type 2 (FGFR2) has emerged as a key oncogenic factor that regulates gastric cancer (GC) progression, but the underlying mechanism of FGF-FGFR2 signaling pathway ...remains largely unknown. To identify the potential molecular mechanisms of the oncogenic FGFR2 in gastric carcinogenesis and convey a novel therapeutic strategy, we profiled the FGFR alterations and analyzed their clinical associations in TCGA and Hong Kong GC cohorts. We found that FGFR2 overexpression in GC cell lines and primary tumors predicted poor survival and was associated with advanced stages of GC. Functionally, growth abilities and cell cycle progression of GC were inhibited by inactivation of ERK-MAPK signal transduction after FGFR2 knockdown, while apoptosis was promoted. Meanwhile, the first-line anti-cancer drug sensitivity was enhanced. RNA-seq analysis further revealed that YAP1 signaling serves as a significant downstream modulator and mediates the oncogenic signaling of FGFR2. When stimulating FGFR2 by rhFGF18, we observed intensified F-actin, nuclear accumulation of YAP1, and overexpression of YAP1 targets, but these effects were attenuated by either FGFR2 depletion or AZD4547 administration. Additionally, the FGF18-FGFR2 signaling upregulated YAP1 expression through activating c-Jun, an effector of MAPK signaling. In our cohort, 28.94% of GC cases were characterized as FGFR2, c-Jun, and YAP1 co-positive and demonstrated worse clinical outcomes. Remarkably, we also found that co-targeting FGFR2 and YAP1 by AZD4547 and Verteporfin synergistically enhanced the antitumor effects in vitro and in vivo. In conclusion, we have identified the oncogenic FGF-FGFR2 regulates YAP1 signaling in GC. The findings also highlight the translational potential of FGFR2-c-Jun-YAP1 axis, which may serve as a prognostic biomarker and therapeutic target for GC.
Interstitial lung diseases (ILDs) comprise different fibrotic lung disorders characterized by cellular proliferation, interstitial inflammation, and fibrosis. The JAK/STAT molecular pathway is ...activated under the interaction of a broad number of profibrotic/pro-inflammatory cytokines, such as IL-6, IL-11, and IL-13, among others, which are increased in different ILDs. Similarly, several growth factors over-expressed in ILDs, such as platelet-derived growth factor (PDGF), transforming growth factor β1 (TGF-β1), and fibroblast growth factor (FGF) activate JAK/STAT by canonical or non-canonical pathways, which indicates a predominant role of JAK/STAT in ILDs. Between the different JAK/STAT isoforms, it appears that JAK2/STAT3 are predominant, initiating cellular changes observed in ILDs. This review analyzes the expression and distribution of different JAK/STAT isoforms in ILDs lung tissue and different cell types related to ILDs, such as lung fibroblasts and alveolar epithelial type II cells and analyzes JAK/STAT activation. The effect of JAK/STAT phosphorylation on cellular fibrotic processes, such as proliferation, senescence, autophagy, endoplasmic reticulum stress, or epithelial/fibroblast to mesenchymal transition will be described. The small molecules directed to inhibit JAK/STAT activation were assayed in vitro and in in vivo models of pulmonary fibrosis, and different JAK inhibitors are currently approved for myeloproliferative disorders. Recent evidence indicates that JAK inhibitors or monoclonal antibodies directed to block IL-6 are used as compassionate use to attenuate the excessive inflammation and lung fibrosis related to SARS-CoV-2 virus. These altogether indicate that JAK/STAT pathway is an attractive target to be proven in future clinical trials of lung fibrotic disorders.
The neovascular form of age-related macular degeneration (AMD), called wet-AMD or choroidal neovascularisation, begins with damage to the outer retinal cells and retinal pigment epithelium (RPE), ...which elicits a cascade of inflammatory and angiogenic responses leading to neovascularisation under the macula. Studies showed that oxidative damage, chronic inflammation of the RPE and complement misregulation work at different steps of this disease. After established neovascularisation, several pro- and antiangiogenic agents start to play an important role. Vascular endothelial growth factors (VEGFs) are the most specific and potent regulators of angiogenesis, which are inhibited by intravitreal injections of ranibizumab, bevacizumab, VEGF Trap, pegaptanib sodium and other agents under investigation. Pigment epithelium-derived factor, on the other hand, shows neuroprotective and antiangiogenic activities. Hepatocyte growth factor (HGF) has a mitogenic effect on a wide range of epithelial and endothelial cells, and it is inhibited by an anti-HGF monoclonal antibody. Platelet-derived growth factor is a potent chemoattractant and mitogen for both fibroblasts and retinal RPE cells, which has been inhibited experimentally by VEGF Trap and human anti-platelet-derived growth factor-D monoclonal antibody. Fibroblast growth factor-2 has pleiotropic effects in different cell and organ systems, and it is blocked by anti-FGF antibodies, with a greater benefit regarding antiangiogenesis when combined treatment with anti-VEGF is performed. Tumour necrosis factor alpha is expressed in the retina and the choroid, and its blockade in choroidal neovascularisation includes the use of monoclonals such as infliximab. This paper reviews the most important cytokines involved in the pathogenesis of wet-AMD, with emphasis on potential combined therapies for disease control.
Inducible gene expression underlies the epigenetically inherited differentiation program of most immune cells. We report that the promoter of the FOXP3 gene possesses two distinct functional states: ...an “off state” mediated by the polycomb histone methyltransferase complex and a histone acetyltransferase-dependent “on state.” Regulating these states is the presence of a Kruppel-like factor (KLF)-containing Polycomb response element. In the KLF10−/− mouse, the FOXP3 promoter is epigenetically silenced by EZH2 (Enhancer of Zeste 2)-mediated trimethylation of Histone 3 K27; thus, impaired FOXP3 induction and inappropriate adaptive T regulatory cell differentiation results in vitro and in vivo. The epigenetic transmittance of adaptive T regulatory cell deficiency is demonstrated throughout more than 40 generations of mice. These results provide insight into chromatin remodeling events key to phenotypic features of distinct T cell populations.
Background: Epigenetic regulation of the T regulatory cell transcriptional program remains unclear.
Results: Without KLF10, Polycomb permanently silences FOXP3, the master transcription factor of T regulatory cells.
Conclusion: Chromatin remodeling events mediated by KLF10 and Polycomb regulate FOXP3 through a Polycomb response element.
Significance: Polycomb and KLFs may direct a heritable, broadly applicable regulatory circuit within T cell development.
Cell differentiation is affected by complex networks of transcription factors that co-ordinate re-organisation of the chromatin landscape. The hierarchies of these relationships can be difficult to ...dissect. During in vitro differentiation of normal human uro-epithelial cells, formaldehyde-assisted isolation of regulatory elements (FAIRE-seq) and RNA-seq was used to identify alterations in chromatin accessibility and gene expression changes following activation of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) as a differentiation-initiating event. Regions of chromatin identified by FAIRE-seq, as having altered accessibility during differentiation, were found to be enriched with sequence-specific binding motifs for transcription factors predicted to be involved in driving basal and differentiated urothelial cell phenotypes, including forkhead box A1 (FOXA1), P63, GRHL2, CTCF and GATA-binding protein 3 (GATA3). In addition, co-occurrence of GATA3 motifs was observed within subsets of differentiation-specific peaks containing P63 or FOXA1. Changes in abundance of GRHL2, GATA3 and P63 were observed in immunoblots of chromatin-enriched extracts. Transient siRNA knockdown of P63 revealed that P63 favoured a basal-like phenotype by inhibiting differentiation and promoting expression of basal marker genes. GATA3 siRNA prevented differentiation-associated downregulation of P63 protein and transcript, and demonstrated positive feedback of GATA3 on PPARG transcript, but showed no effect on FOXA1 transcript or protein expression. This approach indicates that as a transcriptionally regulated programme, urothelial differentiation operates as a heterarchy, wherein GATA3 is able to co-operate with FOXA1 to drive expression of luminal marker genes, but that P63 has potential to transrepress expression of the same genes.
Summary
Pre‐eclampsia (PE) is an obstetric pathology characterized by abnormal activation of the innate and adaptive immune systems dependent on the imbalance of T helper subsets. The present study ...aimed to evaluate the gene and protein expression of T helper type 1 (Th1)/Th2/Th17/regulatory T (Treg) cell transcription factors in peripheral blood lymphocytes from pregnant women with PE employing quantitative RT‐PCR and flow cytometry techniques, as well as the cytokine profile produced by these CD4+ T‐cell subsets in the plasma of pregnant women with PE, classified as early‐onset PE (n = 20), late‐onset PE (n = 20) and normotensive pregnant women (n = 20). Results showed a higher percentage of CD4+ T cells expressing the RORc transcription factor (Th17) and a lower percentage of cells expressing FoxP3 (Treg) in women with early‐onset PE compared with late‐onset PE and normotensive groups. A lower gene expression of GATA‐3 transcription factor was detected in cells of women with early‐onset PE compared with the late‐onset PE group. Endogenous plasma levels of interleukin‐6 (IL‐6), IL‐17 and tumour necrosis factor‐α were significantly higher in the early‐onset PE group than in the late‐onset PE and normotensive groups, whereas IL‐4 (Th2 profile) and IL‐22 (Th17 profile), were not significantly different between the studied groups. The endogenous levels of transforming growth factor‐β and IL‐10 were significantly lower in the pre‐eclamptic than in the normotensive groups of the same gestational age, with a significant difference between early‐ and late‐onset PE. The results show that in women with PE there is an imbalance between inflammatory and anti‐inflammatory profiles in CD4+ T‐cell subsets, with polarization to Th17 profiles in the early‐onset PE, considered as the severe form of PE.
Endogenous characterization of CD4+ T‐cell subsets by expression of the transcription factors T‐bet, RORc, GATA‐3 and FoxP3 in women with pre‐eclampsia and normotensive pregnant women. A deviation of CD4+ lymphocytes to the T helper type 17 profile was more evident in pregnant women with early‐onset pre‐eclampsia, the more severe form of this obstetric pathology.
The transcription factor BATF is required for the differentiation of interleukin 17 (IL-17)-producing helper T cells (TH17 cells) and follicular helper T cells (TFH cells). Here we identified a ...fundamental role for BATF in regulating the differentiation of effector of CD8(+) T cells. BATF-deficient CD8(+) T cells showed profound defects in effector population expansion and underwent proliferative and metabolic catastrophe early after encountering antigen. BATF, together with the transcription factors IRF4 and Jun proteins, bound to and promoted early expression of genes encoding lineage-specific transcription-factors (T-bet and Blimp-1) and cytokine receptors while paradoxically repressing genes encoding effector molecules (IFN-γ and granzyme B). Thus, BATF amplifies T cell antigen receptor (TCR)-dependent expression of transcription factors and augments the propagation of inflammatory signals but restrains the expression of genes encoding effector molecules. This checkpoint prevents irreversible commitment to an effector fate until a critical threshold of downstream transcriptional activity has been achieved.
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