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Background: The Jun proto-oncogene ( JUN ), also referred to as C-JUN , is an integral component of the JNK signaling pathway, which is crucial for the formation and differentiation of spermatogonial stem cells (SSCs). Investigations into the transcriptional regulation of chicken JUN can offer a molecular foundation for elucidating its mechanistic role in SSCs. Methods: In this study, we successfully cloned a 2000 bp upstream sequence of the JUN transcription start site and constructed a series of pGL3 recombinant vectors containing JUN promoters of varying lengths. Results: We verified the promoter activity of the 2000 bp upstream sequence by assessing the fluorescence intensity of DF-1 and identified the promoter activities of different regions via dual-luciferase assays. The transcription of JUN and its promoter region spanning -700 to 0 bp was modulated by an activator of the JNK signaling pathway. Bioinformatics analysis revealed that this -700 to 0 bp region was highly conserved among avian species and predicted the presence of binding sites for Wilms tumor 1 ( WT1 ) and CCAAT/enhancer binding protein alpha ( CEBPA ). The JNK signaling pathway activator was found to upregulate the expression of these transcription factors in DF-1 cells. Through the deletion of binding sites and the overexpression of WT1 and CEBPA , we demonstrated that WT1 inhibited the transcription of JUN , while CEBPA promoted it. Conclusions: In conclusion, the -700 to 0 bp region is the key region of the JUN promoter, with WT1 inhibiting JUN transcription. The results of the study not only provide ideas for exploring the regulatory mechanism of JUN in chicken SSCs, but also lay an important foundation for the study of avian SSCs.

Gastric cancer (GC) is one of the most lethal malignancies worldwide. Despite extensive efforts to develop novel therapeutic targets, effective drugs for GC remain limited. Recent studies have indicated that Lipocalin (LCN)2 abnormalities significantly impact GC progression; however, its regulatory network remains unclear. Our study investigates the functional role and regulatory mechanism of action of LCN2 in GC progression. We observed a positive correlation between LCN2 expression, lower GC grade, and better prognosis in patients with GC. LCN2 overexpression suppressed GC proliferation and metastasis both in vitro and in vivo. Transcriptome sequencing identified secreted protein acidic and rich in cysteine (SPARC) as a pivotal downstream target of LCN2. Mechanistically, c-Jun acted as a transcription factor inducing SPARC expression, and LCN2 downregulated SPARC by inhibiting the JNK/c-Jun pathway. Moreover, LCN2 bound to its receptor, 24p3R, via autocrine signaling, which directly inhibited JNK phosphorylation and then inhibited the JNK/c-Jun pathway. Finally, analysis of clinical data demonstrated that SPARC expression correlated negatively with lower GC grade and better prognosis, and that LCN2 expression correlated negatively with p-JNK, c-Jun, and SPARC expression in GC. These findings suggest that the LCN2/24p3R/JNK/c-Jun/SPARC axis is crucial in the malignant progression of GC, offering novel prognostic markers and therapeutic targets., (© 2024. The Author(s).)

The encoding and evolution of specificity and affinity in protein-protein interactions is poorly understood. Here, we address this question by quantifying how all mutations in one protein, JUN, alter binding to all other members of a protein family, the 54 human basic leucine zipper transcription factors. We fit a global thermodynamic model to the data to reveal that most affinity changing mutations equally affect JUN's affinity to all its interaction partners. Mutations that alter binding specificity are relatively rare but distributed throughout the interaction interface. Specificity is determined both by features that promote on-target interactions and by those that prevent off-target interactions. Approximately half of the specificity-defining residues in JUN contribute both to promoting on-target binding and preventing off-target binding. Nearly all specificity-altering mutations in the interaction interface are pleiotropic, also altering affinity to all partners. In contrast, mutations outside the interface can tune global affinity without affecting specificity. Our results reveal the distributed encoding of specificity and affinity in an interaction interface and how coiled-coils provide an elegant solution to the challenge of optimizing both specificity and affinity in a large protein family., (© 2024. The Author(s).)

Etoposide is a second-line chemotherapy agent widely used for metastatic colorectal cancer. However, we discovered that etoposide treatment induced greater motility potential in four colorectal cancer cell lines. Therefore, we used microarrays to test the mRNA of these cancer cell lines to investigate the mechanisms of etoposide promoting colorectal cancer metastasis. Differentially expressed genes (DEGs) were identified by comparing the gene expression profiles in samples from etoposide-treated cells and untreated cells in all four colorectal cancer cell lines. Next, these genes went through the Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analysis. Among the top 10 genes including the upregulated and downregulated, eight genes had close interaction according to the STRING database: FAS, HMMR, JUN, LMNB1, MLL3, PLK2, STAG1 and TBL1X. After etoposide treatment, the cell cycle, metabolism-related and senescence signaling pathways in the colorectal cancer cell lines were significantly downregulated, whereas necroptosis and oncogene pathways were significantly upregulated. We suggest that the differentially expressed genes LMNB1 and JUN are potential targets for predicting colorectal cancer metastasis. These results provide clinical guidance in chemotherapy, and offer direction for further research in the mechanism of colorectal cancer metastasis., (© 2024. The Author(s).)

Background: N4-Acetylcytidine (ac4C), a highly conserved post-transcriptional mechanism, plays a pivotal role in RNA modification and tumor progression. However, the molecular mechanism by which ac4C modification mediates tumor immunosuppression remains elusive in triple-negative breast cancer (TNBC)., Methods: NAT10 expression was analyzed in TNBC samples in the level of mRNA and protein, and compared with the corresponding normal tissues. ac4C modification levels also measured in the TNBC samples. The effects of NAT10 on immune microenvironment and tumor metabolism were investigated. NAT10-mediated ac4C and its downstream regulatory mechanisms were determined in vitro and in vivo. The combination therapy of targeting NAT10 in TNBC was further explored., Results: The results revealed that the loss of NAT10 inhibited TNBC development and promoted T cell activation. Mechanistically, NAT10 upregulated JunB expression by increasing ac4C modification levels on its mRNA. Moreover, JunB further up-regulated LDHA expression and facilitated glycolysis. By deeply digging, remodelin, a NAT10 inhibitor, elevated the surface expression of CTLA-4 on T cells. The combination of remodelin and CTLA-4 mAb can further activate T cells and inhibite tumor progression., Conclusion: Taken together, our study demonstrated that the NAT10-ac4C-JunB-LDHA pathway increases glycolysis levels and creates an immunosuppressive tumor microenvironment (TME). Consequently, targeting this pathway may assist in the identification of novel therapeutic strategies to improve the efficacy of cancer immunotherapy., (© 2024. The Author(s).)

Yes-associated protein (YAP) and its homolog, transcriptional coactivator with PDZ-binding motif (TAZ), are the main transcriptional downstream effectors of the Hippo pathway. Decreased Hippo pathway activity leads to nuclear translocation of YAP/TAZ where they interact with TEAD transcription factors to induce target gene expression. Unrestrained YAP/TAZ activity can lead to excessive growth and tumor formation in a short time, underscoring the evolutionary need for tight control of these two transcriptional coactivators. Here, we report that the AP-1 component JUN acts as specific repressor of YAP/TAZ at joint target sites to decrease YAP/TAZ activity. This function of JUN is independent of its heterodimeric AP-1 partner FOS and the canonical AP-1 function. Since expression of JUN is itself induced by YAP/TAZ, our work identifies a JUN-dependent negative feedback loop that buffers YAP/TAZ activity at joint genomic sites. This negative feedback loop gets disrupted in liver cancer to unlock the full oncogenic potential of YAP/TAZ. Our results thus demonstrate an additional layer of control for the interplay of YAP/TAZ and AP-1., (© 2024. The Author(s).)

This study investigates the molecular mechanisms behind ischaemia/reperfusion (I/R) injury in the brain, focusing on neuronal apoptosis. It scrutinizes the role of the Jun proto-oncogene in apoptosis, involvement of SOCS1 in neural precursor cell accumulation in ischaemic regions, and the upregulation of C-EBPβ in the hippocampus following I/R. Key to the study is understanding how Jun controls C-EBPβ degradation via SOCS1, potentially offering new clinical treatment avenues for I/R. Techniques such as mRNA sequencing, KEGG enrichment analysis and protein-protein interaction (PPI) in mouse models have indicated involvement of Jun (AP-1) in I/R-induced cerebral damage. The study employs middle cerebral artery occlusion in different mouse models and oxygen-glucose deprivation/reoxygenation in cortical neurons to examine the impacts of Jun and SOCS1 manipulation on cerebral I/R injury and neuronal damage. The findings reveal that I/R reduces Jun expression in the brain, but its restoration lessens cerebral I/R injury and neuron death. Jun activates SOCS1 transcriptionally, leading to C-EBPβ degradation, thereby diminishing cerebral I/R injury through the SOCS1/C-EBPβ pathway. These insights provide a deeper understanding of post-I/R cerebral injury mechanisms and suggest new therapeutic targets for cerebral I/R injury. KEY POINTS: Jun and SOCS1 are poorly expressed, and C-EBPβ is highly expressed in ischaemia/reperfusion mouse brain tissues. Jun transcriptionally activates SOCS1. SOCS1 promotes the ubiquitination-dependent C-EBPβ protein degradation. Jun blunts oxygen-glucose deprivation/reoxygenation-induced neuron apoptosis and alleviates neuronal injury. This study provides a theoretical basis for the management of post-I/R brain injury., (© 2024 The Authors. The Journal of Physiology © 2024 The Physiological Society.)

Silicosis is a systemic disease with predominantly diffuse fibrosis of the lungs due to prolonged inhalation of free SiO 2 dust during the manufacturing process, for which there is no effective treatment. In this study, we used a combined epigenetic and transcriptomic approach to reveal the chromatin-opening features of silicosis and identify the key transcription factor activator protein 1 (AP-1) that responds to silicosis fibrosis. Therapeutic administration of an AP-1 inhibitor inhibits the PI3K/AKT signaling pathway, reduces fibrosis marker proteins, and significantly ameliorates lung fibrosis in a mouse model of silicosis. In addition, it was observed that the expression of Jun and JunB was significantly up-regulated in a TGF-β1-induced in vitro transdifferentiation model of NIH/3T3 cells, and Co-IP confirmed that a protein complex could be formed between Jun and JunB. Mechanistically, silencing of Jun and JunB expression reversed the activation of the PI3K/AKT signaling pathway and the upregulation of fibrosis marker proteins in NIH/3 T3 cells after TGF-β1 stimulation. Taken together, Jun/JunB is expected to be a potential therapeutic target for silicosis fibrosis., Competing Interests: Declaration of competing interest The authors report no conflicts of interest in this work. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ras guanine nucleotide-releasing protein 1 (RasGRP1), a Ras activator, is upregulated in hepatocellular carcinoma (HCC) and other kinds of cancer and is associated with the poor prognosis of patients. However, little is known about the underlying regulatory mechanisms of RasGRP1 in the context of cancer. Here, we report that RasGRP1 physically interacted with the adaptor protein Src homolog and collagen homolog 3 (Shc3). Moreover, RasGRP1 C-terminus domain (aa 607-797) bound to the central collagen-homology 1 (CH1) domain of Shc3. Subsequently, Shc3 enhanced the RasGRP1 tyrosine phosphorylation rate and stability by inhibiting its ubiquitination. Notably, the phosphorylation-mimicking mutants of RasGRP1, RasGRP1 Y704A, and Y748A, rescued the phosphorylation and ubiquitination levels of RasGRP1 in HCC cells. Further investigation showed that the RasGRP1 and Shc3 interaction induced activation of Ras and c-Jun, resulting in cell proliferation in vitro. Moreover, the regulation of Shc3/RasGRP1/Ras/c-Jun signal transduction was confirmed in vivo using the subcutaneous xenograft mouse model. Thus, we propose that continuous Shc3 overexpression may be a possible mechanism for maintaining RasGRP1 stability and that persistent activation of Ras/c-Jun signaling through the interaction of RasGRP1 and Shc3 is a key event increasing cell proliferation. Our findings suggest that the interaction of RasGRP1 and Shc3 plays an important role in HCC tumorigenesis and suggests the potential clinical usage of novel biomarkers and therapeutic targets in HCC., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Filaggrin (FLG) is an essential structural protein expressed in differentiated keratinocytes. Insufficient FLG expression contributes to the pathogenesis of chronic inflammatory skin diseases. Saikosaponin A (SSA), a bioactive oleanane-type triterpenoid, exerts anti-inflammatory activity. However, the effects of topically applied SSA on FLG expression in inflamed skin remain unclear. This study aimed to evaluate the biological activity of SSA in restoring reduced FLG expression. The effect of SSA on FLG expression in HaCaT cells was assessed through various biological methods, including reverse transcription PCR, quantitative real-time PCR, immunoblotting, and immunofluorescence staining. TNFα and IFNγ decreased FLG mRNA, cytoplasmic FLG protein levels, and FLG gene promoter-reporter activity compared to the control groups. However, the presence of SSA restored these effects. A series of FLG promoter-reporter constructs were generated to investigate the underlying mechanism of the effect of SSA on FLG expression. Mutation of the AP1-binding site (mtAP1) in the -343/+25 FLG promoter-reporter abrogated the decrease in reporter activities caused by TNFα + IFNγ, suggesting the importance of the AP1-binding site in reducing FLG expression. The SSA treatment restored FLG expression by inhibiting the expression and nuclear localization of FRA1 and c-Jun, components of AP1, triggered by TNFα + IFNγ stimulation. The ERK1/2 mitogen-activated protein kinase signaling pathway upregulates FRA1 and c-Jun expression, thereby reducing FLG levels. The SSA treatment inhibited ERK1/2 activation caused by TNFα + IFNγ stimulation and reduced the levels of FRA1 and c-Jun proteins in the nucleus, leading to a decrease in the binding of FRA1, c-Jun, p-STAT1, and HDAC1 to the AP1-binding site in the FLG promoter. The effect of SSA was evaluated in an animal study using a BALB/c mouse model, which induces human atopic-dermatitis-like skin lesions via the topical application of dinitrochlorobenzene. Topically applied SSA significantly reduced skin thickening, immune cell infiltration, and the expression of FRA1, c-Jun, and p-ERK1/2 compared to the vehicle-treated group. These results suggest that SSA can effectively recover impaired FLG levels in inflamed skin by preventing the formation of the repressor complex consisting of FRA1, c-Jun, HDAC1, and STAT1.

Deregulation of transcription factors (TFs) leading to uncontrolled proliferation of tumor cells within the microenvironment represents a hallmark of cancer. However, the biological and clinical impact of transcriptional interference, particularly in multiple myeloma (MM) cells, remains poorly understood. The present study shows for the first time that MYC and JUNB, two crucial TFs implicated in MM pathogenesis, orchestrate distinct transcriptional programs. Specifically, our data revealed that expression levels of MYC, JUNB, and their respective downstream targets do not correlate and that their global chromatin-binding patterns are not significantly overlapping. Mechanistically, MYC expression was not affected by JUNB knockdown, and conversely, JUNB expression and transcriptional activity were not affected by MYC knockdown. Moreover, suppression of MYC levels in MM cells via targeting the master regulator BRD4 by either siRNA-mediated knockdown or treatment with the novel proteolysis targeting chimera (PROTAC) MZ-1 overcame bone marrow (BM) stroma cell/IL-6-induced MYC- but not MEK-dependent JUNB-upregulation and transcriptional activity. Consequently, targeting of the two non-overlapping MYC- and JUNB-transcriptoms by MZ-1 in combination with genetic or pharmacological JUNB-targeting approaches synergistically enhanced MM cell death, both in 2D and our novel dynamic 3D models of the BM milieu as well as in murine xenografts. In summary, our data emphasize the opportunity to employ MYC and JUNB dual-targeting treatment strategies in MM as another exciting approach to further improve patient outcomes., (© 2024. The Author(s).)

Background: Hypothermic ischemia-reperfusion arrhythmia is a common complication of cardiothoracic surgery under cardiopulmonary bypass, but few studies have focused on this type of arrhythmia. Our prior study discovered reduced myocardial Cx43 protein levels may be linked to hypothermic reperfusion arrhythmias. However, more detailed molecular mechanism research is required., Method: The microRNA and mRNA expression levels in myocardial tissues were detected by real-time quantitative PCR (RT-qPCR). Besides, the occurrence of hypothermic reperfusion arrhythmias and changes in myocardial electrical conduction were assessed by electrocardiography and ventricular epicardial activation mapping. Furthermore, bioinformatics analysis, applying antagonists of miRNA, western blotting, immunohistochemistry, a dual luciferase assay, and pearson correlation analysis were performed to investigate the underlying molecular mechanisms., Results: The expression level of novel-miR-17 was up-regulated in hypothermic ischemia-reperfusion myocardial tissues. Inhibition of novel-miR-17 upregulation ameliorated cardiomyocyte edema, reduced apoptosis, increased myocardial electrical conduction velocity, and shortened the duration of reperfusion arrhythmias. Mechanistic studies showed that novel-miR-17 reduced the expression of Cx43 by directly targeting Gja1 while mediating the activation of the PKC/c-Jun signaling pathway., Conclusion: Up-regulated novel-miR-17 is a newly discovered pro-arrhythmic microRNA that may serve as a potential therapeutic target and biomarker for hypothermic reperfusion arrhythmias., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Anaplastic thyroid cancer (ATC), an aggressive malignancy with virtually 100% disease-specific mortality, has long posed a formidable challenge in oncology due to its resistance to conventional treatments and the severe side effects associated with current regimens such as doxorubicin chemotherapy. Consequently, there was urgent need to identify novel candidate compounds that could provide innovative therapeutic strategies for ATC. Ophiopogonin D' (OPD'), a triterpenoid saponin extracted, yet its roles in ATC has not been reported. Our data demonstrated that OPD' potently inhibited proliferation and metastasis of ATC cells, promoting cell cycle arrest and apoptosis. Remarkably, OPD' impeded growth and metastasis of ATC in vitro and in vivo, displaying an encouraging safety profile. Regulator of G-protein signalling 4 (RGS4) expression was significantly up-regulated in ATC compared to normal tissues, and this upregulation was suppressed by OPD' treatment. Mechanistically, we elucidated that the transcription factor JUN bound to the RGS4 promoter, driving its transactivation. However, OPD' interacted with JUN, attenuating its transcriptional activity and thereby disrupting RGS4 overexpression. In summary, our research revealed that OPD' bound with JUN, which in turn resulted in the suppression of transcriptional activation of RGS4, thereby eliciting cell cycle arrest and apoptosis in ATC cells. These findings could offer promise in the development of high-quality candidate compounds for treatment in ATC., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

S100P, a member of the S100 calcium-binding protein family, is closely associated with abnormal proliferation, invasion, and metastasis of various cancers. However, its role in the lung adenocarcinoma (LUAD) tumor microenvironment (TME) remains unclear. In this study, we observed specific expression of S100P on tumor cells in LUAD patients through tissue immunofluorescence analysis. Furthermore, this expression was strongly correlated with the recruitment and polarization of tumor-associated macrophages (TAMs). Bioinformatics analysis revealed that high S100P expression is associated with poorer overall survival in LUAD patients. Subsequently, a subcutaneous mouse model demonstrated that S100P promotes recruitment and polarization of TAMs towards the M2 type. Finally, in vitro studies on LUAD cells revealed that S100P enhances the secretion of chemokines and polarizing factors by activating the PKA/c-Jun pathway, which is implicated in TAM recruitment and polarization towards the M2 phenotype. Moreover, inhibition of c-Jun expression impedes the ability of TAMs to infiltrate and polarize towards the M2 phenotype. In conclusion, our study demonstrates that S100P facilitates LUAD cells growth by recruiting M2 TAMs through PKA/c-Jun signaling, resulting in the production of various cytokines. Considering these findings, S100P holds promise as an important diagnostic marker and potential therapeutic target for LUAD., Competing Interests: Declaration of competing interest No conflict of interest exits in the submission of this manuscript, and manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed., (Copyright © 2024. Published by Elsevier Inc.)

GBM is the most threatening form of brain tumor. The advancement of GBM is propelled by the growth, infiltration, and movement of cancer cells. Understanding the underlying mechanisms and identifying new therapeutic agents are crucial for effective GBM treatment. Our research focused on examining the withhold influence of Enhydrin on the destructive activity of GBM cells, both in laboratory settings and within living organisms. By employing network pharmacology and bioinformatics analysis, we have determined that Jun serves as the gene of interest, and EMT as the critical signaling pathway. Mechanistically, Enhydrin inhibits the activity of the target gene Jun to increase the expression of Smad7, which is infinitively regulated by the transcription factor Jun, and as the inhibitory transcription factor, Smad7 can down-regulate TGF-β1 and the subsequent Smad2/3 signaling pathway. Consequently, this whole process greatly hinders the EMT mechanism of GBM, leading to the notable decline in cell proliferation, invasion, and migration. In summary, our research shows that Enhydrin hinders EMT by focusing on the Jun/Smad7/TGF-β1 signaling pathway, presenting a promising target for treating GBM. Moreover, Enhydrin demonstrates encouraging prospects as a new medication for GBM treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Doxorubicin (Dox) has been limited in clinical application due to its cardiac toxicity that varies with the dose. This study aimed to explore how Rhein modulates Dox-induced myocardial toxicity. The general condition and echocardiographic changes of mice were observed to evaluate cardiac function and structure, with myocardial cell injury and apoptosis checked by TUNEL and HE staining. The ELISA assessed markers of myocardial damage and inflammation. The TCMSP and SwissTargetPrediction databases were used to retrieve Rhein's targets while GeneCards was used to find genes related to Dox-induced myocardial injury. Intersection genes were analyzed by Protein-Protein Interaction Networks. The core network genes underwent GO and KEGG enrichment analysis using R software. Western blot was used to detect protein expression. Compared to the Dox group, there was no remarkable difference in heart mass /body mass ratio in the Rhein+Dox group. However, heart mass/tibia length increased. Mice in the Rhein+Dox group had significantly increased LVEF, LVPWs, and LVFS compared to those in the Dox group. Myocardial cell damage, inflammation, and apoptosis significantly reduced in the Rhein+Dox group compared to the model group. Eleven core network genes were selected. Further, Rhein+Dox group showed significantly downregulated expression of p38/p-p38, HSP90AA1, c-Jun/p-c-Jun, c-Fos/p-c-Fos, Bax, and cleaved-caspase-3/caspase-3 while Bcl-2 expression significantly upregulated compared to the Dox group. The study suggests that Rhein mediates cardioprotection against Dox-induced myocardial injury, at least partly, by influencing multiple core genes in the MAPK signaling pathway to inhibit myocardial cell apoptosis., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background & Aims: Psychosocial stress has become an unavoidable part of life, which was reported to promote tumor development. Chronic stress significantly promotes the norepinephrine (NE) secretion and the expression of leptin receptor (LEPR), leading to tumor invasion, metastasis, and proliferation. However, the mechanism of chronic stress-induced tumor proliferation remains unclear., Methods: To reveal the effect of chronic stress on tumor proliferation, subcutaneous tumor models combined with chronic restraint stress (CRS) were established. Combined with the transcript omics database of liver cancer patients, the target pathways were screened and further verified by in vitro experiments., Results: The results showed that the CRS with subcutaneous tumor transplantation (CRS + tumor) group exhibited significantly larger tumor sizes than the subcutaneous tumor transplantation (tumor) group. Compared with the tumor group, CRS obviously increased the mRNA levels of LEPR, FOS, and JUNB of tumor tissues in the CRS + tumor group. Furthermore, the treatment with norepinephrine (NE) significantly elevated the survival rate of H22 cells and enhanced the expression of LEPR, FOS, and JUNB in vitro. Silencing LEPR significantly reduced the expression of FOS and JUNB, accompanied by a decrease in H22 cell viability., Conclusions: Our study demonstrated that CRS activates the LEPR-FOS-JUNB signaling pathway by NE, aggravating tumor development. These findings might provide a scientific foundation for investigating the underlying pathological mechanisms of tumors in response to chronic stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

During implantation, embryos undergo an unpolarized-to-polarized transition to initiate postimplantation morphogenesis. However, the underlying molecular mechanism is unknown. Here, we identify a transient transcriptional activation governing embryonic morphogenesis and pluripotency transition during implantation. In naive pluripotent embryonic stem cells (ESCs), which represent preimplantation embryos, we find that the microprocessor component DGCR8 can recognize stem-loop structures within nascent mRNAs to sequester transcriptional coactivator FLII to suppress transcription directly. When mESCs exit from naive pluripotency, the ERK/RSK/P70S6K pathway rapidly activates, leading to FLII phosphorylation and disruption of DGCR8/FLII interaction. Phosphorylated FLII can bind to transcription factor JUN, activating cell migration-related genes to establish poised pluripotency akin to implanting embryos. Resequestration of FLII by DGCR8 drives poised ESCs into formative pluripotency. In summary, we identify a DGCR8/FLII/JUN-mediated transient transcriptional activation mechanism. Disruption of this mechanism inhibits naive-poised-formative pluripotency transition and the corresponding unpolarized-to-polarized transition during embryo implantation, which are conserved in mice and humans., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Chimeric antigen receptor (CAR) T cells show suboptimal efficacy in acute myeloid leukemia (AML). We find that CAR T cells exposed to myeloid leukemia show impaired activation and cytolytic function, accompanied by impaired antigen receptor downstream calcium, ZAP70, ERK, and C-JUN signaling, compared to those exposed to B-cell leukemia. These defects are caused in part by the high expression of CD155 by AML. Overexpressing C-JUN, but not other antigen receptor downstream components, maximally restores anti-tumor function. C-JUN overexpression increases costimulatory molecules and cytokines through reinvigoration of ERK or transcriptional activation, independent of anti-exhaustion. We conduct an open-label, non-randomized, single-arm, phase I trial of C-JUN-overexpressing CAR-T in AML (NCT04835519) with safety and efficacy as primary and secondary endpoints, respectively. Of the four patients treated, one has grade 4 (dose-limiting toxicity) and three have grade 1-2 cytokine release syndrome. Two patients have no detectable bone marrow blasts and one patient has blast reduction after treatment. Thus, overexpressing C-JUN endows CAR-T efficacy in AML., (© 2024. The Author(s).)

Background: The neuropathic pain with complex networks of neuroinflammatory activation severely limits clinical therapeutic research. TNF receptor-associated factor 6 (TRAF6) is associated with multiple inflammatory diseases. However, there remains confusion about the effects and mechanisms of TRAF6 in neuropathic pain., Methods: A chronic constriction injury (CCI) model was developed to simulate neuralgia in vivo. We overexpressed or knocked down TRAF6 in CCI mice, respectively. Activation of microglia by TRAF6, the inflammatory response, and disease progression were inspected using WB, qRT-PCR, immunofluorescence, flow cytometry, and ELISA assays. Moreover, the mechanism of M1/M2 polarization activation of microglia by TRAF6 was elaborated in BV-2 cells., Results: TRAF6 was enhanced in the spinal neurons and microglia of the CCI mice model compared with the sham operation group.. Down-regulation of TRAF6 rescued the expression of Iba-1. In response to mechanical and thermal stimulation, PWT and PWL were improved after the knockdown of TRAF6. Decreased levels of pro-inflammatory factors were observed in TRAF6 knockdown groups. Meanwhile, increased microglial M1 markers induced by CCI were limited in mice with TRAF6 knockdown. In addition, TRAF6 overexpression has the precise opposite effect on CCI mice or microglia polarization. We also identifed that TRAF6 activated the c-JUN/NF-kB pathway signaling; the inhibitor of c-JUN/NF-kB could effectively alleviate the neuropathic pain induced by upregulated TRAF6 in the CCI mice model., Conclusion: In summary, this study indicated that TRAF6 was concerned with neuropathic pain, and targeting the TRAF6/c-JUN/NF-kB pathway may be a prospective target for treating neuropathic pain., (© 2024. The Author(s).)

Systemic lupus erythematosus (SLE) is prototypical autoimmune disease driven by pathological T cell-B cell interactions 1,2 . Expansion of T follicular helper (T FH ) and T peripheral helper (T PH ) cells, two T cell populations that provide help to B cells, is a prominent feature of SLE 3,4 . Human T FH and T PH cells characteristically produce high levels of the B cell chemoattractant CXCL13 (refs.  5,6 ), yet regulation of T cell CXCL13 production and the relationship between CXCL13 + T cells and other T cell states remains unclear. Here, we identify an imbalance in CD4 + T cell phenotypes in patients with SLE, with expansion of PD-1 + /ICOS + CXCL13 + T cells and reduction of CD96 hi IL-22 + T cells. Using CRISPR screens, we identify the aryl hydrocarbon receptor (AHR) as a potent negative regulator of CXCL13 production by human CD4 + T cells. Transcriptomic, epigenetic and functional studies demonstrate that AHR coordinates with AP-1 family member JUN to prevent CXCL13 + T PH /T FH cell differentiation and promote an IL-22 + phenotype. Type I interferon, a pathogenic driver of SLE 7 , opposes AHR and JUN to promote T cell production of CXCL13. These results place CXCL13 + T PH /T FH cells on a polarization axis opposite from T helper 22 (T H 22) cells and reveal AHR, JUN and interferon as key regulators of these divergent T cell states., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Exploring the molecular mechanisms of PD-1/PDL-1 blockade for non-small cell lung cancer (NSCLC) would facilitate understanding for tumor microenvironment (TME) and development of individualized medicine. To date, biomarkers of response to PD-1 blockade therapy were still limited. In this study, we hypothesize that cell type in the tumor microenvironment can influence the effect of PD-1 blockade immunotherapy through specific genes. Therefore, we re-analyze the single-cell RNA sequencing data and validation in tissue from lung adenocarcinoma patients. Dynamic changes of cellular subpopulation were observed after anti-PD-1 immunotherapy among TMEs between primary/metastasis or good/poor response patients. Non-exhausted CD8 T cells and dysregulated genes were observed in responsing patients from PD-1 blockade therapy. Among all changed genes, JUN, involved in PD-1 blockade immunotherapy pathway, and could be considered as a PD-1 responsing biomarker.

FOXA family proteins act as pioneer factors by remodeling compact chromatin structures. FOXA1 is crucial for the chromatin binding of the androgen receptor (AR) in both normal prostate epithelial cells and the luminal subtype of prostate cancer (PCa). Recent studies have highlighted the emergence of FOXA2 as an adaptive response to AR signaling inhibition treatments. However, the role of the FOXA1 to FOXA2 transition in regulating cancer lineage plasticity remains unclear. Our study demonstrates that FOXA2 binds to distinct classes of developmental enhancers in multiple AR-independent PCa subtypes, with its binding depending on LSD1. Moreover, we reveal that FOXA2 collaborates with JUN at chromatin and promotes transcriptional reprogramming of AP-1 in lineage-plastic cancer cells, thereby facilitating cell state transitions to multiple lineages. Overall, our findings underscore the pivotal role of FOXA2 as a pan-plasticity driver that rewires AP-1 to induce the differential transcriptional reprogramming necessary for cancer cell lineage plasticity., (© 2024. The Author(s).)

As an important protein encoded by hepatitis B virus (HBV), HBV X protein (HBx) plays an important role in the development of hepatocellular carcinoma (HCC). It has been shown that seven in absentia homologue 1 (SIAH1) could regulates the degradation of HBx through the ubiquitin-proteasome pathway. However, as a member of SIAH family, the regulatory effects of SIAH2 on HBx remain unclear. In this study, we first confirmed that SIAH2 could reduce the protein levels of HBx depending on its E3 ligase activity. Moreover, SIAH2 interacted with HBx and induced its K48-linked polyubiquitination and proteasomal degradation. Furthermore, we provided evidence that SIAH2 inhibits HBx-associated HCC cells proliferation by regulating HBx. In conclusion, our study identified a novel role for SIAH2 in promoting HBx degradation and SIAH2 exerts an inhibitory effect in the proliferation of HBx-associated HCC through inducing the degradation of HBx. Our study provides a new idea for the targeted degradation of HBx and may have great huge significance into providing novel evidence for the targeted therapy of HBV-infected HCC., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Diffuse large B-cell lymphoma (DLBCL) stands out as the most common type of malignant cancer, representing the majority of cases of non-Hodgkin's lymphoma. Ethyl pyruvate (EP) is a derivative of pyruvic acid and found to have potent anti-tumor properties. Despite its potential benefits, the impact of EP on DLBCL remains ambiguous. Our objective is to elucidate the role of EP in modulating the development of DLBCL. Analysis of cholecystokinin-8 (CCK-8) revealed that treatment with EP significantly diminished the viability of DLBCL cells. Furthermore, EP administration suppressed colony formation and hindered cell adhesion and invasion in DLBCL cells. Examination of cell cycle progression showed that EP treatment induced arrest at the G1 phase and subsequently reduced the S phase population in DLBCL cells. EP treatment consistently exhibited apoptosis-inducing properties in Annexin-V assays, and notably downregulated the expression of Bcl-2 while increasing levels of proapoptotic cleaved caspase 3 and BAX in DLBCL cells. Additionally, EP treatment decreased the overexpression of c-Jun in c-Jun-transfected DLBCL cells. Further, EP demonstrated DNA-damaging effects in TUNEL assays. In vivo, xenograft animal models revealed that EP treatment significantly mitigated DLBCL tumor growth and suppressed DLBCL cell adhesion to bone marrow stromal cells. In summary, these findings suggest that EP mitigates DLBCL progression by inducing apoptosis, inducing cell cycle arrest, and promoting DNA damage., Competing Interests: The authors report no conflicts of interest in this work.

Transient receptor potential melastatin-8 (TRPM8) is a cation channel that is activated by cold and "cooling agents" such as menthol and icilin, which induce a cold sensation. The stimulation of TRPM8 activates an intracellular signaling cascade that ultimately leads to a change in the gene expression pattern of the cells. Here, we investigate the TRPM8-induced signaling pathway that links TRPM8 channel activation to gene transcription. Using a pharmacological approach, we show that the inhibition of phosphatidylinositol 4-phosphate 5 kinase α (PIP5K), an enzyme essential for the biosynthesis of phosphatidylinositol 4,5-bisphosphate, attenuates TRPM8-induced gene transcription. Analyzing the link between TRPM8 and Gq proteins, we show that the pharmacological inhibition of the βγ subunits impairs TRPM8 signaling. In addition, genetic studies show that TRPM8 requires an activated Gα subunit for signaling. In the nucleus, the TRPM8-induced signaling cascade triggers the activation of the transcription factor AP-1, a complex consisting of a dimer of basic region leucine zipper (bZIP) transcription factors. Here, we identify the bZIP protein c-Jun as an essential component of AP-1 within the TRPM8-induced signaling cascade. In summary, with PIP5K, Gq subunits, and c-Jun, we identified key molecules in TRPM8-induced signaling from the plasma membrane to the nucleus.

Benzene, a widely used industrial chemical, has been clarified to cause hematotoxicity. Our previous study suggested that miR-451a may play a role in benzene-induced impairment of erythroid differentiation. However, the mechanism underlying remains unclear. In this study, we explored the role of miR-451a and its underlying mechanisms in hydroquinone (HQ)-induced suppression of erythroid differentiation in K562 cells. 0, 1.0, 2.5, 5.0, 10.0, and 50 μM HQ treatment of K562 cells resulted in a dose-dependent inhibition of erythroid differentiation, as well as the expression of miR-451a. Bioinformatics analysis was conducted to predict potential target genes of miR-451a and dual-luciferase reporter assays confirmed that miR-451a can directly bind to the 3'-UTR regions of BATF, SETD5, and ARHGEF3 mRNAs. We further demonstrated that over-expression or down-regulation of miR-451a altered the expression of BATF, SETD5, and ARHGEF3, and also modified erythroid differentiation. In addition, BATF, SETD5, and ARHGEF3 were verified to play a role in HQ-induced inhibition of erythroid differentiation in this study. Knockdown of SETD5 and ARHGEF3 reversed HQ-induced suppression of erythroid differentiation while knockdown of BATF had the opposite effect. On the other hand, we also identified c-Jun as a potential transcriptional regulator of miR-451a. Forced expression of c-Jun increased miR-451a expression and reversed the inhibition of erythroid differentiation induced by HQ, whereas knockdown of c-Jun had the opposite effect. And the binding site of c-Jun and miR-451a was verified by dual-luciferase reporter assay. Collectively, our findings indicate that miR-451a and its downstream targets BATF, SETD5, and ARHGEF3 are involved in HQ-induced erythroid differentiation disorder, and c-Jun regulates miR-451a as a transcriptional regulator in this process., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 Elsevier B.V. All rights reserved.)

Extracellular vesicles (EVs) derived from mouse bone marrow mesenchymal stem cells (mBMSCs) convey the CAV1 protein, influencing the TGF-β1/SMAD2/c-JUN pathway and thus the molecular mechanisms underlying myocardial fibrosis (MF) post-myocardial infarction (MI). Through various experimental methods, including transmission electron microscopy, Nanosight analysis, Western blot, ELISA, and qRT-PCR, we isolated, purified, and identified EVs originating from mBMSCs. Bioinformatics and experimental findings show a reduced expression of CAV1 in myocardial fibrosis tissue. Furthermore, our findings suggest that mBMSC-EVs can deliver CAV1 to cardiac fibroblasts (CFs) and that silencing CAV1 in mBMSC-EVs promotes CF fibrosis. In vivo studies further corroborated these findings. In conclusion, mBMSC-EVs mitigate myocardial fibrosis in MI mice by delivering the CAV1 protein, inhibiting the TGF-β1/SMAD2/c-JUN pathway., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: The developmental immaturity of the innate immune system helps explains the increased risk of infection in the neonatal period. Importantly, innate immune signaling pathways such as p65/NFκB and c-Jun/AP1 are responsible for the prevention of hepatocyte apoptosis in adult animals, yet whether developmental immaturity of these pathways increases the risk of hepatic injury in the neonatal period is unknown., Methods: Using a murine model of endotoxemia (LPS 5 mg/kg IP x 1) in neonatal (P3) and adult mice, we evaluated histologic evidence of hepatic injury and apoptosis, presence of p65/NFκB and c-Jun/AP1 activation and associated transcriptional regulation of apoptotic genes., Results: We demonstrate that in contrast to adults, endotoxemic neonatal (P3) mice exhibit a significant increase in hepatic apoptosis. This is associated with absent hepatic p65/NFκB signaling and impaired expression of anti-apoptotic target genes. Hepatic c-Jun/AP1 activity was attenuated in endotoxemic P3 mice, with resulting upregulation of pro-apoptotic factors., Conclusions: These results demonstrate that developmental absence of innate immune p65/NFκB and c-Jun/AP1 signaling, and target gene expression is associated with apoptotic injury in neonatal mice. More work is needed to determine if this contributes to long-term hepatic dysfunction, and whether immunomodulatory approaches can prevent this injury., Impact: Various aspects of developmental immaturity of the innate immune system may help explain the increased risk of infection in the neonatal period. In adult models of inflammation and infection, innate immune signaling pathways such as p65/NFκB and c-Jun/AP1 are responsible for a protective, pro-inflammatory transcriptome and regulation of apoptosis. We demonstrate that in contrast to adults, endotoxemic neonatal (P3) mice exhibit a significant increase in hepatic apoptosis associated with absent hepatic p65/NFκB signaling and c-Jun/AP1 activity. We believe that these results may explain in part hepatic dysfunction with neonatal sepsis, and that there may be unrecognized developmental and long-term hepatic implications of early life exposure to systemic inflammatory stress., (© 2024. The Author(s), under exclusive licence to the International Pediatric Research Foundation, Inc.)

Background: Prostate cancer develops through malignant transformation of the prostate epithelium in a stepwise, mutation-driven process. Although activator protein-1 transcription factors such as JUN have been implicated as potential oncogenic drivers, the molecular programs contributing to prostate cancer progression are not fully understood., Methods: We analyzed JUN expression in clinical prostate cancer samples across different stages and investigated its functional role in a Pten-deficient mouse model. We performed histopathological examinations, transcriptomic analyses and explored the senescence-associated secretory phenotype in the tumor microenvironment., Results: Elevated JUN levels characterized early-stage prostate cancer and predicted improved survival in human and murine samples. Immune-phenotyping of Pten-deficient prostates revealed high accumulation of tumor-infiltrating leukocytes, particularly innate immune cells, neutrophils and macrophages as well as high levels of STAT3 activation and IL-1β production. Jun depletion in a Pten-deficient background prevented immune cell attraction which was accompanied by significant reduction of active STAT3 and IL-1β and accelerated prostate tumor growth. Comparative transcriptome profiling of prostate epithelial cells revealed a senescence-associated gene signature, upregulation of pro-inflammatory processes involved in immune cell attraction and of chemokines such as IL-1β, TNF-α, CCL3 and CCL8 in Pten-deficient prostates. Strikingly, JUN depletion reversed both the senescence-associated secretory phenotype and senescence-associated immune cell infiltration but had no impact on cell cycle arrest. As a result, JUN depletion in Pten-deficient prostates interfered with the senescence-associated immune clearance and accelerated tumor growth., Conclusions: Our results suggest that JUN acts as tumor-suppressor and decelerates the progression of prostate cancer by transcriptional regulation of senescence- and inflammation-associated genes. This study opens avenues for novel treatment strategies that could impede disease progression and improve patient outcomes., (© 2024. The Author(s).)

CXCR4, JUNB and PD-L1 are implicated in cancer progression and metastasis. The current study investigated these biomarkers in CTCs isolated from metastatic prostate cancer (mPCa) patients at the RNA and protein levels. CTCs were isolated from 48 mPCa patients using the Ficoll density gradient and ISET system (17 out of 48). The (CK/PD-L1/CD45) and (CK/CXCR4/JUNB) phenotypes were identified using two triple immunofluorescence stainings followed by VyCAP platform analysis. Molecular analysis was conducted with an EpCAM-dependent method for 25/48 patients. CK-8 , CK-18 , CK-19 , JUNB , CXCR4 , PD-L1 , and B2M (reference gene) were analyzed with RT-qPCR. The (CK+/PD-L1+/CD45-) and the (CK+/CXCR4+/JUNB+) were the most frequent phenotypes (61.1% and 62.5%, respectively). Furthermore, the (CK+/CXCR4+/JUNB-) phenotype was correlated with poorer progression-free survival [(PFS), HR: 2.5, p = 0.049], while the (CK+/PD-L1+/CD45-) phenotype was linked to decreased overall survival [(OS), HR: 262.7, p = 0.007]. Molecular analysis revealed that 76.0% of the samples were positive for CK-8,18 , and 19 , while 28.0% were positive for JUNB , 44.0% for CXCR4 , and 48.0% for PD-L1 . Conclusively, CXCR4, JUNB, and PD-L1 were highly expressed in CTCs from mPCa patients. The CXCR4 protein expression was associated with poorer PFS, while PD-L1 was correlated with decreased OS, providing new biomarkers with potential clinical relevance.

Cancer cells employ adaptive mechanisms to survive various stressors, including genotoxic drugs. Understanding the factors promoting survival is crucial for developing effective treatments. In this study, we unveil a previously unexplored long non-coding RNA, JUNI (JUN-DT, LINC01135), which is upregulated by genotoxic drugs through the activation of stress-activated MAPKs, JNK, and p38 and consequently exerts positive control over the expression of its adjacent gene product c-Jun, a well-known oncoprotein, which transduces signals to multiple transcriptional outputs. JUNI regulates cellular migration and has a crucial role in conferring cellular resistance to chemotherapeutic drugs or UV radiation. Depletion of JUNI markedly increases the sensitivity of cultured cells and spheroids to chemotherapeutic agents. We identified 57 proteins interacting with JUNI. The activity of one of them the MAPK phosphatase and inhibitor, DUSP14, is counteracted by JUNI, thereby, facilitating efficient JNK phosphorylation and c-Jun induction when cells are exposed to UV radiation. The antagonistic interplay with DUSP14 contributes not only to c-Jun induction but also augments the survival of UV-exposed cells. In summary, we introduce JUNI as a novel stress-inducible regulator of c-Jun, positioning it as a potential target for enhancing the sensitivity of cancer cells to chemotherapy., (© 2024. The Author(s).)

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death. HCC incidence is on the rise, while treatment options remain limited. Thus, a better understanding of the molecular pathways involved in HCC development has become a priority to guide future therapies. While previous studies implicated the Activator Protein-1 (AP-1) (Fos/Jun) transcription factor family members c-Fos and c-Jun in HCC formation, the contribution of Fos-related antigens (Fra-) 1 and 2 is unknown. Here, we show that hepatocyte-restricted expression of a single chain c-Jun~Fra-2 protein, which functionally mimics the c-Jun/Fra-2 AP-1 dimer, results in spontaneous HCC formation in c-Jun~Fra-2 hep mice. Several hallmarks of human HCC, such as cell cycle dysregulation and the expression of HCC markers are observed in liver tumors arising in c-Jun~Fra-2 hep mice. Tumorigenesis occurs in the context of mild inflammation, low-grade fibrosis, and Pparγ-driven dyslipidemia. Subsequent analyses revealed increased expression of c-Myc, evidently under direct regulation by AP-1 through a conserved distal 3' enhancer. Importantly, c-Jun~Fra-2-induced tumors revert upon switching off transgene expression, suggesting oncogene addiction to the c-Jun~Fra-2 transgene. Tumors escaping reversion maintained c-Myc and c-Myc target gene expression, likely due to increased c-Fos. Interfering with c-Myc in established tumors using the Bromodomain and Extra-Terminal motif inhibitor JQ-1 diminished liver tumor growth in c-Jun~Fra-2 mutant mice. Thus, our data establish c-Jun~Fra-2 hep mice as a model to study liver tumorigenesis and identify the c-Jun/Fra-2-Myc interaction as a potential target to improve HCC patient stratification and/or therapy., Competing Interests: Competing interests statement:The authors declare no competing interest.

Therapy resistance and metastatic progression jointly determine the fatal outcome of cancer, therefore, elucidating their crosstalk may provide new opportunities to improve therapeutic efficacy and prevent recurrence and metastasis in esophageal squamous cell carcinoma (ESCC). Here, we have established radioresistant ESCC cells with the remarkable metastatic capacity, and identified miR-494-3p (miR494) as a radioresistant activator. Mechanistically, we demonstrated that cullin 3 (CUL3) is a direct target of miR494, which is transcriptionally regulated by JunD, and highlighted that JunD-miR494-CUL3 axis promotes radioresistance and metastasis by facilitating epithelial-mesenchymal transition (EMT) and restraining programmed cell death 1 ligand 1 (PD-L1) degradation. In clinical specimens, miR494 is significantly up-regulated and positively associated with T stage and lymph node metastasis in ESCC tissues and serum. Notably, patients with higher serum miR494 expression have poor prognosis, and patients with higher CUL3 expression have more conventional dendritic cells (cDCs) and plasmacytoid DCs (pDCs), less cancer-associated fibroblasts (CAF2/4), and tumor endothelial cells (TEC2/3) infiltration than patients with lower CUL3 expression, suggesting that CUL3 may be involved in tumor microenvironment (TME). Overall, miR494 may serve as a potential prognostic predictor and therapeutic target, providing a promising strategy for ESCC treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

IL-33 is a cytokine central to type 2 immune pathology in chronic airway disease. This cytokine is abundantly expressed in the respiratory epithelium and increased in disease, but how expression is regulated is undefined. Here we show that increased IL33 expression occurs from multiple noncanonical promoters in human chronic obstructive pulmonary disease (COPD), and it facilitates production of alternatively spliced isoforms in airway cells. We found that phorbol 12-myristate 13-acetate (PMA) can activate IL33 promoters through protein kinase C in primary airway cells and lines. Transcription factor (TF) binding arrays combined with RNA interference identified activator protein (AP) TFs as regulators of baseline and induced IL33 promoter activity. ATAC-Seq and ChIP-PCR identified chromatin accessibility and differential TF binding as additional control points for transcription from noncanonical promoters. In support of a role for these TFs in COPD pathogenesis, we found that AP-2 (TFAP2A, TFAP2C) and AP-1 (FOS and JUN) family members are upregulated in human COPD specimens. This study implicates integrative and pioneer TFs in regulating IL33 promoters and alternative splicing in human airway basal cells. Our work reveals a potentially novel approach for targeting IL-33 in development of therapeutics for COPD.

Gasdermin E (GSDME) has recently been identified as a critical executioner to mediate pyroptosis. While epidermal keratinocytes can initiate GSDME-mediated pyroptosis, the role of keratinocyte GSDME in psoriatic dermatitis remains poorly characterized. Through analysis of GEO datasets, we found elevated GSDME levels in psoriatic lesional skin. Additionally, GSDME levels correlated with both psoriasis severity and response to biologics treatments. Single-cell RNA sequencing (scRNA-seq) from a GEO dataset revealed GSDME upregulation in keratinocytes of psoriasis patients. In the imiquimod (IMQ)-induced psoriasis-like dermatitis mouse model, both full-length and cleaved forms of caspase-3 and GSDME were elevated in the epidermis. Abnormal proliferation and differentiation of keratinocytes and dermatitis were attenuated in Gsdme -/- mice and keratinocyte-specific Gsdme conditional knockout mice after IMQ stimulation. Exposure of keratinocytes to mixed cytokines (M5), mimicking psoriatic conditions, led to GSDME cleavage. Moreover, the interaction between GSDME-FL and p65 or c-jun was significantly increased after M5 stimulation. GSDME knockdown inhibited nuclear translocation of p65 and c-jun and decreased upregulation of psoriatic inflammatory mediators such as IL1β, CCL20, CXCL1, CXCL8, S100A8, and S100A9 in M5-challenged keratinocytes. In conclusion, GSDME in keratinocytes contributes to the pathogenesis and progression of psoriasis, potentially in a pyroptosis-independent manner by interacting and promoting translocation of p65 and c-jun. These findings suggest that keratinocyte GSDME could serve as a potential therapeutic target for psoriasis treatment., (© 2024. The Author(s).)

Fos-related antigen-2 (Fra-2) is the most recently discovered member of the Fos family and, by dimerizing with Jun proteins, forms the activator protein 1 (AP-1) transcription factor. By inducing or repressing the transcription of several target genes, Fra-2 is critically involved in the modulation of cell response to a variety of extracellular stimuli, stressors and intracellular changes. In physiological conditions, Fra-2 has been found to be ubiquitously expressed in human cells, regulating differentiation and homeostasis of bone, muscle, nervous, lymphoid and other tissues. While other AP-1 members, like Jun and Fos, are well characterized, studies of Fra-2 functions in cancer are still at an early stage. Due to the lack of a trans-activating domain, which is present in other Fos proteins, it has been suggested that Fra-2 might inhibit cell transformation, eventually exerting an anti-tumor effect. In human malignancies, however, Fra-2 activity is enhanced (or induced) by dysregulation of microRNAs, oncogenes and extracellular signaling, suggesting a multifaceted role. Therefore, Fra-2 can promote or prevent transformation, proliferation, migration, epithelial-mesenchymal transition, drug resistance and metastasis formation in a tumor- and context-dependent manner. Intriguingly, recent data reports that Fra-2 is also expressed in cancer associated cells, contributing to the intricate crosstalk between neoplastic and non-neoplastic cells, that leads to the evolution and remodeling of the tumor microenvironment. In this review we summarize three decades of research on Fra-2, focusing on its oncogenic and anti-oncogenic effects in tumor progression and dissemination., (© 2023. The Author(s).)

Right ventricular dysfunction is a key clinical issue for the viability of donation-after-circulatory-death (DCD) heart transplantation. DCD hearts with volume overload have the potential to exhibit aggravated right ventricular dysfunction following heart transplantation. The c-jun/c-fos mRNAs are genes that immediately respond to myocardial cell stretch. We assessed myocardial cell stretch during asphyxia-induced cardiac arrest by measuring c-jun/c-fos mRNA expression levels. The trachea was dissected and ligated to initiate asphyxiation in anesthetized Wistar rats under paralyzed ventilation. The hearts were harvested at 4 time points: 0, 15, 30, and 45 minutes after the termination of ventilation. Free walls of the right and left ventricles and the interventricular septum were sectioned. Total RNA was extracted from these tissues, and cDNA was synthesized using reverse transcription. The c-jun/c-fos mRNA expression levels were quantified using the droplet digital polymerase chain reaction method. In the left ventricle, c-jun/c-fos expression levels rapidly increased at 15 minutes, but the expression levels returned to the baseline level at 30 minutes after tracheal ligation. In contrast, in the right ventricle, c-jun/c-fos expression levels gradually increased and peaked 30 minutes after tracheal ligation. Myocardial cell stretching in the right ventricle is prolonged after asphyxia-induced cardiac arrest compared to that in the left ventricle, which may lead to right ventricular dysfunction after DCD heart transplantation.

Background: Morbidity and mortality associated with cardiovascular diseases, such as myocardial infarction, stem from the inability of terminally differentiated cardiomyocytes to regenerate, and thus repair the damaged myocardial tissue structure. The molecular biological mechanisms behind the lack of regenerative capacity for those cardiomyocytes remains to be fully elucidated. Recent studies have shown that c-Jun serves as a cell cycle regulator for somatic cell fates, playing a key role in multiple molecular pathways, including the inhibition of cellular reprogramming, promoting angiogenesis, and aggravation of cardiac hypertrophy, but its role in cardiac development is largely unknown. This study aims to delineate the role of c-Jun in promoting early-stage cardiac differentiation., Methods: The c-Jun gene in mouse embryonic stem cells (mESCs) was knocked out with CRISPR-Cas9, and the hanging drop method used to prepare the resulting embryoid bodies. Cardiac differentiation was evaluated up to 9 days after c-Jun knockout (ko) via immunofluorescence, flow cytometric, and qPCR analyses., Results: Compared to the wild-type control group, obvious beating was observed among the c-Jun-ko mESCs after 6 days, which was also associated with significant increases in myocardial marker expression. Additionally, markers associated with mesoderm and endoderm cell layer development, essential for further differentiation of ESCs into cardiomyocytes, were also up-regulated in the c-Jun-ko cell group., Conclusions: Knocking out c-Jun directs ESCs toward a meso-endodermal cell lineage fate, in turn leading to generation of beating myocardial cells. Thus, c-Jun plays an important role in regulating early cardiac cell development., (© 2023. The Author(s).)

Background: Enhancer dysregulation is one of the important features for cancer cells. Enhancers enriched with H3K4me3 have been implicated to play important roles in cancer. However, their detailed features and regulatory mechanisms have not been well characterized., Results: Here, we profile the landscape of H3K4me3-enriched enhancers (m3Es) in 43 pairs of colorectal cancer (CRC) samples. M3Es are widely distributed in CRC and averagely possess around 10% of total active enhancers. We identify 1322 gain variant m3Es and 367 lost variant m3Es in CRC. The target genes of the gain m3Es are enriched in immune response pathways. We experimentally prove that repression of CBX8 and RPS6KA5 m3Es inhibits target gene expression in CRC. Furthermore, we find histone methyltransferase MLL1 is responsible for depositing H3K4me3 on the identified Vm3Es. We demonstrate that the transcription factor AP1/JUN interacts with MLL1 and regulates m3E activity. Application of a small chemical inhibitor for MLL1 activity, OICR-9429, represses target gene expression of the identified Vm3Es, enhances anti-tumor immunity and inhibits CRC growth in an animal model., Conclusions: Taken together, our study illustrates the genome-wide landscape and the regulatory mechanisms of m3Es in CRC, and reveals potential novel strategies for cancer treatment., (© 2023. The Author(s).)

Luminal breast cancer has the highest bone metastasis frequency among all breast cancer subtypes; however, its metastatic mechanism has not been elucidated because of a lack of appropriate models. We have previously developed useful bone metastatic cell lines of luminal breast cancer using MCF7 cells. In this study, we characterized bone metastatic MCF7-BM cell lines and identified c-Jun as a novel bone metastasis marker of luminal breast cancer. The protein level of c-Jun was upregulated in MCF7-BM cells compared with that in parental cells, and its deficiency resulted in the suppression of tumor cell migration, transformation, and reduced osteolytic ability. In vivo, dominant-negative c-Jun exhibited smaller bone metastatic lesions and a lower metastatic frequency. Histologic analysis revealed that c-Jun expression was heterogeneous in bone metastatic lesions, whereas c-Jun overexpression mediated a vicious cycle between MCF7-BM cells and osteoclasts by enhancing calcium-induced migration and releasing the osteoclast activator BMP5. Pharmacological inhibition of c-Jun by the Jun amino-terminal kinase (JNK) inhibitor JNK-IN-8 effectively suppressed tumorigenesis and bone metastasis in MCF7-BM cells. Furthermore, c-Jun downstream signals were specifically correlated with the clinical prognosis of patients with the luminal subtype of breast cancer. Our results illustrate the potential benefits of a therapy that targets c-Jun to prevent bone metastasis in luminal breast cancer., Implications: c-Jun expression mediates bone metastasis in luminal breast cancer by forming a vicious cycle in the bone microenvironment, which reveals potential strategies for subtype-specific bone metastasis therapy., (©2023 American Association for Cancer Research.)

Loss of c-JUN leads to early mouse embryonic death, possibly because of a failure to develop a normal cardiac system. How c-JUN regulates human cardiomyocyte cell fate remains unknown. Here, we used the in vitro differentiation of human pluripotent stem cells into cardiomyocytes to study the role of c-JUN. Surprisingly, the knockout of c-JUN improved cardiomyocyte generation, as determined by the number of TNNT2+ cells. ATAC-seq data showed that the c-JUN defect led to increased chromatin accessibility on critical regulatory elements related to cardiomyocyte development. ChIP-seq data showed that the knockout c-JUN increased RBBP5 and SETD1B expression, leading to improved H3K4me3 deposition on key genes that regulate cardiogenesis. The c-JUN KO phenotype could be copied using the histone demethylase inhibitor CPI-455, which also up-regulated H3K4me3 levels and increased cardiomyocyte generation. Single-cell RNA-seq data defined three cell branches, and knockout c-JUN activated more regulons that are related to cardiogenesis. In summary, our data demonstrated that c-JUN could regulate cardiomyocyte cell fate by modulating H3K4me3 modification and chromatin accessibility and shed light on how c-JUN regulates heart development in humans., (© 2023 Zhong et al.)

Activator protein-1 (AP-1) is a transcription factor that consists of a diverse group of members including Jun, Fos, Maf, and ATF. AP-1 involves a number of processes such as proliferation, migration, and invasion in cells. Dysfunctional AP-1 activity is associated with cancer initiation, development, invasion, migration and drug resistance. Therefore, AP-1 is a potential target for cancer targeted therapy. Currently, some small molecule inhibitors targeting AP-1 have been developed and tested, showing some anticancer effects. However, AP-1 is complex and diverse in its structure and function, and different dimers may play different roles in different type of cancers. Therefore, more research is needed to reveal the specific mechanisms of AP-1 in cancer, and how to select appropriate inhibitors and treatment strategies. Ultimately, this review summarizes the potential of combination therapy for cancer., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Song, Lian and Zhang.)

Objectives: Long non-coding RNAs (lncRNAs) play important roles in RA pathogenesis. However, specific lncRNAs that regulate gene expression in RA pathogenesis are poorly known. This study was undertaken to characterize a novel lncRNA (lnc-RNU12) that has a lower-than-normal expression level in RA patients., Methods: We performed initial genome-wide lncRNA microarray screening in peripheral blood mononuclear cells from 28 RA cases and 18 controls. Multiple methods were used to validate the detected associations between lncRNAs and RA. Furthermore, we identified the source and characteristics of the highlighted lncRNAs, detected the target genes, and determined the functional effect on immune cells through lncRNA knock-down in Jurkat T cell lines., Results: lnc-RNU12 was downregulated in peripheral blood mononuclear cells and T cell subtypes of RA patients and was genetically associated with RA risk. lnc-RNU12 mediates the effect of microbiome alterations on RA risk. Activation of T cells caused low expression of lnc-RNU12. Knock-down of lnc-RNU12 in Jurkat T cells caused cell cycle S-phase arrest and altered the expression of protein-coding genes related to the cell cycle and apoptosis (e.g. c-JUN, CCNL2, CDK6, MYC, RNF40, PKM, VPS35, DNAJB6 and FLCN). Finally, c-JUN and CCNL2 were identified as target genes of lnc-RNU12 at the mRNA and protein expression levels. RNA-binding protein immunoprecipitation assays verified the interaction between lnc-RNU12 and the two proteins (c-Jun and cyclin L2) in Jurkat cells., Conclusions: Our study suggested that lnc-RNU12 was involved in the pathogenesis of RA by influencing the T cell cycle by targeting c-JUN and CCNL2., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: Esophageal squamous cell carcinoma (ESCC) is a globally aggressive malignant tumor. This study aimed to investigate the mechanism of JUND in ESCC development via MAPRE2., Methods: ESCC cells (KYSE-450 and ECA109) were transfected with small interfering RNA (si)-JUND, si-MAPRE2, si-JUND, or pcDNA3.1-MAPRE2. JUND and MAPRE2 expression in ESCC cells was detected with quantitative real-time polymerase chain reaction and western blot. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were used to determine ESCC cell proliferation. Dual-luciferase reporter gene and chromatin immunoprecipitation assays were performed to assess binding between JUND and MAPRE2. Human umbilical vein endothelial cells (HUVECs) were co-cultured with ESCC cell supernatants. Angiogenesis was assessed with an in vitro angiogenesis assay. Western blot was conducted to evaluate the expression of angiogenic proteins [vascular endothelial growth factor A (VEGFA), matrix metallopeptidase 9 (MMP-9), and angiopoietin-2 (ang2)]., Results: The levels of expression of JUND and MAPRE2 were high in ESCC cells. Mechanistically, JUND bound to MAPRE2 promoter and increased MAPRE2 transcription. Downregulation of JUND or MAPRE2 inhibited KYSE-450 and ECA109 cell proliferation and reduced the levels of expression of VEGFA, MMP-9, and ang2 and tube formation in HUVECs co-cultured with ESCC cell supernatants. MAPRE2 upregulation counteracted the inhibitory effects of JUND silencing on cell proliferative and angiogenic capabilities in ESCC., Conclusions: JUND promoted MAPRE2 transcription, thereby facilitating cell proliferative and angiogenic abilities in ESCC., Competing Interests: Conflicts of interest The authors declare there is no conflict of interest regarding this study., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Hepatocellular carcinoma, as a common liver cirrhosis complication, has become the sixth most common cancer worldwide, and its increasing incidence has resulted in considerable medical and economic burdens. As a natural polyphenolic compound, kaempferol has exhibits a wide range of antitumor activities against multiple cancer targets. In this study, the Autodock software was used for molecular docking to simulate the interaction process between kaempferol and HCC targets and the PyMOL software was used for visualization. Proliferation of kaempferol HepG2 cells under the effect of kaempferol was detected using Cell Counting Kit-8 (CCK-8) assay, and the apoptosis rate of HepG2 cells was detected using flow cytometry. The expressions of proteins BAX, CDK1, and JUN protein expressions were detected by Western blot. Molecular docking found that the kaempferol ligand has 3 rotatable bonds, 6 nonpolar hydrogen atoms, and 12 aromatic carbon atoms, and can form complexes with the kaempferol targets P53, BAX, AR, CDK1, and JUN through electrostatic energy. GO (Gene Ontology) enrichment analysis suggests that kaempferol regulates the biological function of hepatocellular carcinoma cells and is related to apoptosis. Cell Counting Kit-8 assay suggested that Kaempferol can significantly inhibited HepG2 cell proliferation, and the inhibition rate increased with the increase in drug concentration and incubation time. Moreover, kaempferol can promoted HepG2 cell apoptosis in a dose-dependent manner. This compound upregulated BAX and JUN expression and downregulated CDK1 expression. Thus, Kaempferol can promote HepG2 cell apoptosis, and the regulatory mechanism may be related to the regulation of the expression levels of the apoptosis-related proteins BAX, CDK1, and JUN., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Diverse mouse strains have different health and life spans, mimicking the diversity among humans. To capture conserved aging signatures, we studied long-lived C57BL/6J and short-lived NZO/HILtJ mouse strains by profiling transcriptomes and epigenomes of immune cells from peripheral blood and the spleen from young and old mice. Transcriptional activation of the AP-1 transcription factor complex, particularly Fos, Junb, and Jun genes, was the most significant and conserved aging signature across tissues and strains. ATAC-seq data analyses showed that the chromatin around these genes was more accessible with age and there were significantly more binding sites for these TFs with age across all studied tissues, targeting pro-inflammatory molecules including Il6. Age-related increases in binding sites of JUN and FOS factors were also conserved in human peripheral blood ATAC-seq data. Single-cell RNA-seq data from the mouse aging cell atlas Tabula Muris Senis showed that the expression of these genes increased with age in B, T, NK cells, and macrophages, with macrophages from old mice expressing these molecules more abundantly than other cells. Functional data showed that upon myeloid cell activation via poly(I:C), the levels of JUN protein and its binding activity increased more significantly in spleen cells from old compared to young mice. In addition, upon activation, old cells produced more IL6 compared to young cells. In sum, we showed that the aging-related transcriptional activation of Jun and Fos family members in AP-1 complex is conserved across immune tissues and long- and short-living mouse strains, possibly contributing to increased inflammation with age., (© 2023 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

The function of the stem cell system is supported by a stereotypical shape of the niche structure. In Drosophila ovarian germarium, somatic cap cells form a dish-like niche structure that allows only two or three germ-line stem cells (GSCs) reside in the niche. Despite extensive studies on the mechanism of stem cell maintenance, the mechanisms of how the dish-like niche structure is shaped and how this structure contributes to the stem cell system have been elusive. Here, we show that a transmembrane protein Stranded at second (Sas) and its receptor Protein tyrosine phosphatase 10D (Ptp10D), effectors of axon guidance and cell competition via epidermal growth factor receptor (Egfr) inhibition, shape the dish-like niche structure by facilitating c-Jun N-terminal kinase (JNK)-mediated apoptosis. Loss of Sas or Ptp10D in gonadal apical cells, but not in GSCs or cap cells, during the pre-pupal stage results in abnormal shaping of the niche structure in the adult, which allows excessive, four to six GSCs reside in the niche. Mechanistically, loss of Sas-Ptp10D elevates Egfr signaling in the gonadal apical cells, thereby suppressing their naturally-occurring JNK-mediated apoptosis that is essential for the shaping of the dish-like niche structure by neighboring cap cells. Notably, the abnormal niche shape and resulting excessive GSCs lead to diminished egg production. Our data propose a concept that the stereotypical shaping of the niche structure optimizes the stem cell system, thereby maximizing the reproductive capacity., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Taniguchi, Igaki. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Microenvironmental bystander cells are essential for the progression of chronic lymphocytic leukemia (CLL). We have discovered previously that LYN kinase promotes the formation of a microenvironmental niche for CLL. Here we provide mechanistic evidence that LYN regulates the polarization of stromal fibroblasts to support leukemic progression. LYN is overexpressed in fibroblasts of lymph nodes of CLL patients. LYN-deficient stromal cells reduce CLL growth in vivo. LYN-deficient fibroblasts show markedly reduced leukemia feeding capacity in vitro. Multi-omics profiling reveals that LYN regulates the polarization of fibroblasts towards an inflammatory cancer-associated phenotype through modulation of cytokine secretion and extracellular matrix composition. Mechanistically, LYN deletion reduces inflammatory signaling including reduction of c-JUN expression, which in turn augments the expression of Thrombospondin-1, which binds to CD47 thereby impairing CLL viability. Together, our findings suggest that LYN is essential for rewiring fibroblasts towards a leukemia-supportive phenotype., (© 2023. The Author(s).)

Hedgehog (Hh) signaling pathway includes canonical and non-canonical activation manners. In colorectal cancer, we have previously shown that PGE2-JNK could initiate non-canonical activation of the Hh signaling pathway. In this study, we showed that c-Jun, a classic substrate of JNK, increased Gli2 protein stability after phosphorylated by PGE2. Suppressing the function of c-Jun or JNK indicated that c-Jun prevents Gli2 from protease degradation caused by PGE2-JNK. Moreoer, we revealed that less ubiquitination of Gli2 was detected in colorectal cancer cells treated with PGE2 while suppression of c-Jun restored the ubiquitination of Gli2. In addition, we observed that suppression of c-Jun significantly decreased Gli2 expression no matter when Gli2 remained in phosphorylation or non-phosphorylation state. These phenomena were recapitulated, when the endpoint of Gli2 expression was replaced by Gli2 ubiquitination. Furthermore, we demonstrated that restricting c-Jun function ablated the PGE2-provoked Hh activity and proliferation of colorectal cancer cells. These results elucidated that the evasion of Gli2 with phosphorylation from proteasomal-ubiquitin degradation needed the cooperation of phosphorylated c-Jun by kinase JNK, which contributed to promoting Hh activation and the proliferation of colorectal cancer cells. This study provides a theoretical foundation to target PGE2 downstream for the prevention and treatment of colorectal cancer., Competing Interests: Declaration of competing interest All authors declare no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)