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Abstract Background Increased Galectin 3‐binding protein (LGALS3BP) serum levels have been used to assess hepatic fibrosis stages and the severity of hepatocellular carcinoma (HCC). Considering the crucial role of transforming growth factor‐β1 (TGF‐β1) in the emergence of these diseases, the present study tested the hypothesis that LGALS3BP regulates the TGF‐β1 signaling pathway. Methods The expression levels of LGALS3BP and TGFB1 were analyzed in patients with metabolic dysfunction‐associated steatohepatitis (MASH) and HCC. Multiple omics techniques, such as RNA‐sequencing, transposase‐accessible chromatin‐sequencing assay, and liquid chromatography‐tandem mass spectrometry proteomics, were used to identify the regulatory mechanisms for the LGALS3BP‐TGF‐β1 axis. The effects of altered TGF‐β1 signaling by LGALS3BP were investigated in conditional LGALS3BP‐knockin and LGALS3BP‐knockout mice. Results In patients with MASH and HCC, the levels of LGALS3BP and TGFB1 exhibited positive correlations. Stimulation of LGALS3BP by the inflammatory cytokine interferon α in HCC cells or ectopic overexpression of LGALS3BP in hepatocytes promoted the expression levels of TGFB1. Aggravated fibrosis was observed in the livers of hepatocyte‐specific LGALS3BP‐knockin mice, with increased TGFB1 levels. LGALS3BP directly bound to and assembled integrin αV, an integral mediator required for releasing active TGF‐β1 from extracellular latent complex with the rearranged F‐actin cytoskeleton. The released TGF‐β1 activated JunB transcription factor, which in turn promoted the TGF‐β1 positive feedback loop. LGALS3BP deletion in the hepatocytes downregulated TGF‐β1 signaling and CCl4 induced fibrosis. Moreover, LGALS3BP depletion hindered hepatocarcinogenesis by limiting the availability of fibrogenic TGF‐β1. Conclusion LGALS3BP plays a crucial role in hepatic fibrosis and carcinogenesis by controlling the TGF‐β1 signaling pathway, making it a promising therapeutic target in TGF‐β1‐related diseases.

HIV-1 relies extensively on host cell machinery for replication. Identification and characterization of these host-virus interactions is vital to our understanding of viral replication and the consequences of infection in cells. Several prior screens have identified host factors important for HIV replication but with limited replication of findings, likely due to differences in experimental design and conditions. Thus, unidentified factors likely exist. To identify novel host factors required for HIV-1 infection, we performed a genome-wide CRISPR/Cas9 screen using HIV-induced cell death as a partitioning method. We created a gene knockout library in TZM-GFP reporter cells using GeCKOv2, which targets 19,050 genes, and infected the library with a lethal dose of HIV-1NL4-3. We hypothesized that cells with a knockout of a gene critical for HIV infection would survive while cells with a knockout of a non-consequential gene would undergo HIV-induced death and be lost from the population. Surviving cells were analyzed by high throughput sequencing of the integrated CRISPR/Cas9 cassette to identify the gene knockout. Of the gene targets, an overwhelming majority of the surviving cells harbored the guide sequence for the AP-1 transcription factor family protein, JunB. Upon the generation of a clonal JunB knockout cell line, we found that HIV-1NL4-3 infection was blocked in the absence of JunB. The phenotype resulted from downregulation of CXCR4, as infection levels were recovered by reintroduction of CXCR4 in JunB KO cells. Thus, JunB downmodulates CXCR4 expression in TZM-GFP cells, reducing CXCR4-tropic HIV infection. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Adipose tissue is a crucial metabolic organ in the human body. It stores and exerts distinct physiological functions in different body regions. Fat not only serves as a cushion and insulator but also stores energy and conveys endocrine signals within the body. There is a growing recognition that adipose tissue is an organ that is misunderstood and underestimated in contribution to human health and disease progression by regulating its size and functionality. In mammals, the adipose tissue reservoir consists of three functionally distinct types of fat: white adipose tissue (WAT), brown adipose tissue (BAT), and beige or inducible brown adipose tissue (iWAT), which exhibits thermogenic capabilities intermediate between the other two. Fat in different depots exhibits considerable differences in origin, characteristics, and functions. They vary not only in adipocyte lineage, properties, thermogenesis, and endocrine functions but also in their immunological functions. In a recent study published in Nature Metabolism, Zhang et al. investigated the role of JunB in the thermogenic capacity of adipocytes and its significance in obesity and metabolic disorders. The study revealed that JunB expression in BAT coexists with both low and high thermogenic adipocytes, indicating a fundamental feature of heterogeneity and plasticity within BAT. In summary, this article demonstrates that research targeting JunB holds promise for improving diet-induced obesity and insulin resistance, offering new avenues for treating metabolic disorders.

Abstract In animal species that have the capability of regenerating tissues and limbs, cell proliferation is enhanced after wound healing and is essential for the reconstruction of injured tissue. Although the ability to induce cell proliferation is a common feature of such species, the molecular mechanisms that regulate the transition from wound healing to regenerative cell proliferation remain unclear. Here, we show that upon injury, InhibinβA and JunB cooperatively function for this transition during Xenopus tadpole tail regeneration. We found that the expression of inhibin subunit beta A (inhba) and junB proto-oncogene (junb) is induced by injury-activated TGF-β/Smad and MEK/ERK signaling in regenerating tails. Similarly to junb knockout (KO) tadpoles, inhba KO tadpoles show a delay in tail regeneration, and inhba/junb double KO (DKO) tadpoles exhibit severe impairment of tail regeneration compared with either inhba KO or junb KO tadpoles. Importantly, this impairment is associated with a significant reduction of cell proliferation in regenerating tissue. Moreover, JunB regulates tail regeneration via FGF signaling, while InhibinβA likely acts through different mechanisms. These results demonstrate that the cooperation of injury-induced InhibinβA and JunB is critical for regenerative cell proliferation, which is necessary for re-outgrowth of regenerating Xenopus tadpole tails.

Background and Aims: The regenerative capacity of the pancreas diminishes with age. Understanding acinar cell responses to injury and the resolution of regenerative processes is crucial for tissue homeostasis. However, knowledge about the impact of aging on these processes remains limited. Methods: To investigate the influence of aging on pancreas regeneration, we established a cohort of young (7–14 weeks) and old (18 months) C57bl/6 mice. Experimental pancreatitis was induced using caerulein, and pancreas samples were collected at various time points after induction, covering acute damage response, inflammation, peak proliferation, and inflammation resolution. Our analysis involved immunohistochemistry, quantitative imaging, and gene expression analyses. Results: Our study revealed a significant decline in the regenerative capacity of the pancreas in old mice. Despite similar morphology and transcriptional profiles between the pancreas of young and old mice under homeostasis, the aged pancreas is primed to generate an exacerbated proinflammatory reaction in response to injury. Specifically, we observed notable upregulation of Junb expression in acinar cells and aberrant myofibroblast activation in the aged pancreas. Conclusion: The response of acinar cells to injury in the pancreas of aged mice is characterized by an increased susceptibility to inflammation and stromal reactions. Our findings uncover a pre-existing proinflammatory state in aged acinar cells, offering insights into potential strategies to prevent the onset of pancreatic insufficiency and the development of inflammatory conditions. These insights hold implications for preventing conditions such as chronic pancreatitis and pancreatic ductal adenocarcinoma.

In animal species that have the capability of regenerating tissues and limbs, cell proliferation is enhanced after wound healing and is essential for the reconstruction of injured tissue. Although the ability to induce cell proliferation is a common feature of such species, the molecular mechanisms that regulate the transition from wound healing to regenerative cell proliferation remain unclear. Here, we show that upon injury, InhibinβA and JunB cooperatively function for this transition during Xenopus tadpole tail regeneration. We found that the expression of inhibin subunit beta A (inhba) and junB proto-oncogene (junb) is induced by injury-activated TGF-β/Smad and MEK/ERK signaling in regenerating tails. Similarly to junb knockout (KO) tadpoles, inhba KO tadpoles show a delay in tail regeneration, and inhba/junb double KO (DKO) tadpoles exhibit severe impairment of tail regeneration compared with either inhba KO or junb KO tadpoles. Importantly, this impairment is associated with a significant reduction of cell proliferation in regenerating tissue. Moreover, JunB regulates tail regeneration via FGF signaling, while InhibinβA likely acts through different mechanisms. These results demonstrate that the cooperation of injury-induced InhibinβA and JunB is critical for regenerative cell proliferation, which is necessary for re-outgrowth of regenerating Xenopus tadpole tails. [ABSTRACT FROM AUTHOR]

• Stress-induced fluctuations in daily affect associated with immune gene expression. • Greater decrease in positive affect to stress associated with higher JUNB expression. • JUNB may mediate association between stress and systemic markers of inflammation. Affective reactivity to stress is a person-level measurement of how well an individual copes with daily stressors. A common method of measuring affective reactivity entails the estimation of within-person differences of either positive or negative affect on days with and without stressors present. Individuals more reactive to common stressors, as evidenced by affective reactivity measurements, have been shown to have increased levels of circulating pro-inflammatory markers. While affective reactivity has previously been associated with inflammatory markers, the upstream mechanistic links underlying these associations are unknown. Using data from the Midlife in the United States (MIDUS) Refresher study (N = 195; 52% female; 84% white), we quantified daily stress processes over 10 days and determined individuals' positive and negative affective reactivities to stressors. We then examined affective reactivity association with peripheral blood mononuclear cell (PBMC) gene expression of the immune-related conserved transcriptional response to adversity. Results indicated that individuals with a greater decrease in positive affect to daily stressors exhibited heightened PBMC JUNB expression after Bonferroni corrections (p-adjusted < 0.05). JUNB encodes a protein that acts as a transcription factor which regulates many aspects of the immune response, including inflammation and cell proliferation. Due to its critical role in the activation of macrophages and maintenance of CD4+ T-cells during inflammation, JUNB may serve as a potential upstream mechanistic target for future studies of the connection between affective reactivity and inflammatory processes. Overall, our findings provide evidence that affective reactivity to stress is associated with levels of immune cell gene expression. [ABSTRACT FROM AUTHOR]

Endothelial damage is the initial and crucial factor in the occurrence and development of vascular complications in diabetic patients, contributing to morbidity and mortality. Although hyperglycemia has been identified as a damaging effector, the detailed mechanisms remain elusive. In this study, identified by ATAC-seq and RNA-seq, JunB reverses the inhibition of proliferation and the promotion of apoptosis in human umbilical vein endothelial cells treated with high glucose, mainly through the cell cycle and p53 signaling pathways. Furthermore, JunB undergoes phase separation in the nucleus and in vitro , mediated by its intrinsic disordered region and DNA-binding domain. Nuclear localization and condensation behaviors are required for JunB-mediated proliferation and apoptosis. Thus, our study uncovers the roles of JunB and its coacervation in repairing vascular endothelial damage caused by high glucose, elucidating the involvement of phase separation in diabetes and diabetic endothelial dysfunction. [ABSTRACT FROM AUTHOR]

HIV-1 relies extensively on host cell machinery for replication. Identification and characterization of these host-virus interactions is vital to our understanding of viral replication and the consequences of infection in cells. Several prior screens have identified host factors important for HIV replication but with limited replication of findings, likely due to differences in experimental design and conditions. Thus, unidentified factors likely exist. To identify novel host factors required for HIV-1 infection, we performed a genome-wide CRISPR/Cas9 screen using HIV-induced cell death as a partitioning method. We created a gene knockout library in TZM-GFP reporter cells using GeCKOv2, which targets 19,050 genes, and infected the library with a lethal dose of HIV-1NL4-3. We hypothesized that cells with a knockout of a gene critical for HIV infection would survive while cells with a knockout of a non-consequential gene would undergo HIV-induced death and be lost from the population. Surviving cells were analyzed by high throughput sequencing of the integrated CRISPR/Cas9 cassette to identify the gene knockout. Of the gene targets, an overwhelming majority of the surviving cells harbored the guide sequence for the AP-1 transcription factor family protein, JunB. Upon the generation of a clonal JunB knockout cell line, we found that HIV-1NL4-3 infection was blocked in the absence of JunB. The phenotype resulted from downregulation of CXCR4, as infection levels were recovered by reintroduction of CXCR4 in JunB KO cells. Thus, JunB downmodulates CXCR4 expression in TZM-GFP cells, reducing CXCR4-tropic HIV infection.

Currently, platinum-containing regimens are the most commonly used regimens for advanced gastric cancer patients, and chemotherapy resistance is one of the main reasons for treatment failure. Thus, it is important to reveal the mechanism of oxaliplatin resistance and to seek effective intervention strategies to improve chemotherapy sensitivity, thereby improving the survival and prognosis of gastric cancer patients. To understand the molecular mechanisms of oxaliplatin resistance, we generate an oxaliplatin-resistant gastric cancer cell line and conduct assay for transposase-accessible chromatin sequencing (ATAC-seq) and RNA sequencing (RNA-seq) for both parental and oxaliplatin-resistant AGS cells. A total of 3232 genomic regions are identified to have higher accessibility in oxaliplatin-resistant cells, and DNA-binding motif analysis identifies JUNB as the core transcription factor in the regulatory network. JUNB is overexpressed in oxaliplatin-resistant gastric cancer cells, and its upregulation is associated with poor prognosis in gastric cancer patients, which is validated by our tissue microarray data. Moreover, chromatin immunoprecipitation sequencing (ChIP-seq) analysis reveals that JUNB binds to the transcriptional start site of key genes involved in the MAPK signaling pathway. Knockdown of JUNB inhibits the MAPK signaling pathway and restores sensitivity to oxaliplatin. Combined treatment with the ERK inhibitor piperlongumine or MEK inhibitor trametinib effectively overcomes oxaliplatin resistance. This study provides evidence that JUNB mediates oxaliplatin resistance in gastric cancer by activating the MAPK pathway. The combination of MAPK inhibitors with oxaliplatin overcomes resistance to oxaliplatin, providing a promising treatment opportunity for oxaliplatin-resistant gastric cancer patients.

Simple Summary: Brain metastasis is a devastating but common consequence of advanced stage melanomas. The interactions between cancer cells and non-cancerous cells in the tumor microenvironment alleviate cancer progression. Previously, we found that brain metastatic melanoma cells reprogrammed microglia into tumor-promoting cells, but the mechanism is yet to be clarified. Here, we identified the transcription factor JunB to be dramatically upregulated in microglia following their exposure to melanoma. We recognized a diverse range (high and low) of JunB expression levels in melanoma-associated microglia, and therefore sought to establish two different microglia populations, expressing high or low levels of JunB, and to delineate their involvement in melanoma brain metastasis progression. High-JunB microglia demonstrated pro-tumor properties, while low-JunB microglia demonstrated anti-tumor properties. Moreover, we described the mechanism by which JunB upregulation is induced by melanoma cells. Microglia highly expressing JunB may serve as a target for brain-metastasizing melanoma therapy. Reciprocal signaling between melanoma brain metastatic (MBM) cells and microglia reprograms the phenotype of both interaction partners, including upregulation of the transcription factor JunB in microglia. Here, we aimed to elucidate the impact of microglial JunB upregulation on MBM progression. For molecular profiling, we employed RNA-seq and reverse-phase protein array (RPPA). To test microglial JunB functions, we generated microglia variants stably overexpressing JunB (JunBhi) or with downregulated levels of JunB (JunBlo). Melanoma-derived factors, namely leukemia inhibitory factor (LIF), controlled JunB upregulation through Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling. The expression levels of JunB in melanoma-associated microglia were heterogeneous. Flow cytometry analysis revealed the existence of basal-level JunB-expressing microglia alongside microglia highly expressing JunB. Proteomic profiling revealed a differential protein expression in JunBhi and JunBlo cells, namely the expression of microglia activation markers Iba-1 and CD150, and the immunosuppressive molecules SOCS3 and PD-L1. Functionally, JunBhi microglia displayed decreased migratory capacity and phagocytic activity. JunBlo microglia reduced melanoma proliferation and migration, while JunBhi microglia preserved the ability of melanoma cells to proliferate in three-dimensional co-cultures, that was abrogated by targeting leukemia inhibitory factor receptor (LIFR) in control microglia–melanoma spheroids. Altogether, these data highlight a melanoma-mediated heterogenous effect on microglial JunB expression, dictating the nature of their functional involvement in MBM progression. Targeting microglia highly expressing JunB may potentially be utilized for MBM theranostics. [ABSTRACT FROM AUTHOR]

Jun B proto-oncogene (JunB) is a crucial member of dimeric activator protein-1 (AP-1) complex, which plays a significant role in various physiological processes, such as placental formation, cardiovascular development, myelopoiesis, angiogenesis, endochondral ossification and epidermis tissue homeostasis. Additionally, it has been reported that JunB has great regulatory functions in innate and adaptive immune responses by regulating the differentiation and cytokine secretion of immune cells including T cells, dendritic cells and macrophages, while also facilitating the effector of neutrophils and natural killer cells. Furthermore, a growing body of studies have shown that JunB is involved in tumorigenesis through regulating cell proliferation, differentiation, senescence and metastasis, particularly affecting the tumor microenvironment through transcriptional promotion or suppression of oncogenes in tumor cells or immune cells. This review summarizes the physiological function of JunB, its immune regulatory function, and its contribution to tumorigenesis, especially focusing on its regulatory mechanisms within tumor-associated immune processes. [ABSTRACT FROM AUTHOR]

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.

Background & Aims: Circadian rhythms play significant roles in immune responses, and many inflammatory processes in liver diseases are associated with malfunctioning molecular clocks. However, the significance of the circadian clock in autoimmune hepatitis (AIH), which is characterised by immune-mediated hepatocyte destruction and extensive inflammatory cytokine production, remains unclear. Methods: We tested the difference in susceptibility to the immune-mediated liver injury induced by concanavalin A (ConA) at various time points throughout a day in mice and analysed the effects of global, hepatocyte, or myeloid cell deletion of the core clock gene, Bmal1 (basic helix–loop–helix ARNT-like 1), on liver injury and inflammatory responses. Multiple molecular biology techniques and mice with macrophage-specific knockdown of Junb, a Bmal1 target gene, were used to investigate the involvement of Junb in the circadian control of ConA-induced hepatitis. Results: The susceptibility to ConA-induced liver injury is highly dependent on the timing of ConA injection. The treatment at Zeitgeber time 0 (lights on) triggers the highest mortality as well as the severest liver injury and inflammatory responses. Further study revealed that this timing effect was driven by macrophage, but not hepatocyte, Bmal1. Mechanistically, Bmal1 controls the diurnal variation of ConA-induced hepatitis by directly regulating the circadian transcription of Junb and promoting M1 macrophage activation. Inhibition of Junb in macrophages blunts the administration time-dependent effect of ConA and attenuates liver injury. Moreover, we demonstrated that Junb promotes macrophage inflammation by regulating AKT and extracellular signal-regulated kinase (ERK) signalling pathways. Conclusions: Our findings uncover a critical role of the Bmal1–Junb–AKT/ERK axis in the circadian control of ConA-induced hepatitis and provide new insights into the prevention and treatment of AIH. Impact and Implications: This study unveils a critical role of the Bmal1–Junb–AKT/ERK axis in the circadian control of ConA-induced liver injury, providing new insights into the prevention and treatment of immune-mediated hepatitis, including autoimmune hepatitis (AIH). The findings have scientific implications as they enhance our understanding of the circadian regulation of immune responses in liver diseases. Furthermore, clinically, this research offers opportunities for optimising treatment strategies in immune-mediated hepatitis by considering the timing of therapeutic interventions.

Cadherins are transmembrane proteins that mediate cell-to-cell adhesion and various cellular processes. In Sertoli cells of the testis, Cdh2 contributes to the development of the testis and the formation of the blood-testis barrier, being essential for germ cells' protection. Analyses of chromatin accessibility and epigenetic marks in adult mouse testis have shown that the region from −800 to +900 bp respective to Cdh2 transcription start site (TSS) is likely the active regulatory region of this gene. In addition, the JASPAR 2022 matrix has predicted an AP-1 binding element at about −600 bp. Transcription factors of the activator protein 1 (AP-1) family have been implicated in the regulation of the expression of genes encoding cell-to-cell interaction proteins such as Gja1 , Nectin2 and Cdh3. To test the potential regulation of Cdh2 by members of the AP-1 family, siRNAs were transfected into TM4 Sertoli cells. The knockdown of Junb led to a decrease in Cdh2 expression. ChIP-qPCR and luciferase reporter assays with site-directed mutagenesis confirmed the recruitment of Junb to several AP-1 regulatory elements in the proximal region of the Cdh2 promoter in TM4 cells. Further investigation with luciferase reporter assays showed that other AP-1 members can also activate the Cdh2 promoter albeit to a lesser extent than Junb. Taken together, these data suggest that in TM4 Sertoli cells, Junb is responsible for the regulation of Cdh2 expression which requires its recruitment to the proximal region of the Cdh2 promoter. • Junb directly regulates Cdh2 expression in TM4 Sertoli cells. • Junb is recruited to three AP-1 DNA regulatory elements of the Cdh2 promoter. • Individual AP-1 transcription factors activate the Cdh2 promoter. • Members between JUN and FOS sub-family fail to cooperatively activate Cdh2 promoter. [ABSTRACT FROM AUTHOR]

We have recently demonstrated that fibroblast growth factor receptor 2 (FGFR2)‐mediated signalling alters progesterone receptor (PR) activity and response of oestrogen receptor α (ER)‐positive (ER+) breast cancer (BCa) cell lines to anti‐ER agents. Little is known about whether the crosstalk between ER and PR, shown to be modulated by the hormonal background, might also be affected by FGFR2. Here, PR‐dependent behaviour of ER+ BCa cells was studied in the presence of oestrogen (E2) and progesterone (P4) and/or FGF7. In vitro analyses showed that FGF7/FGFR2 signalling: (a) abolished the effect of P4 on E2‐promoted 3D cell growth and response to tamoxifen; (b) regulated ER and PR expression and activity; (c) increased formation of ER–PR complexes; and (d) reversed P4‐triggered deregulation of ER‐dependent genes. Analysis of clinical data demonstrated that the prognostic value of FGFR2 varied between patients with different menopausal status; that is, high expression of FGFR2 was significantly associated with longer progression‐free survival (PFS) in postmenopausal patients, whereas there was no significant association in premenopausal patients. FGFR2 was found to positively correlate with the expression of JunB proto‐oncogene, AP‐1 transcription factor subunit (JUNB), an ER‐dependent gene, only in premenopausal patients. Molecular analyses revealed that the presence of JunB was a prerequisite for FGFR2‐mediated abrogation of P4‐induced inhibition of cell growth. Our results demonstrate for the first time that the FGF7/FGFR2–JunB axis abolishes the modulatory effects of PR on ER‐associated biological functions in premenopausal ER+ BCa. This may provide foundations for a better selection of patients for FGFR‐targeting therapeutic strategies.

Simple Summary: While invading tumor-adjacent tissue, cancer cells often undergo epithelial-mesenchymal transition (EMT). A mechanistic understanding of EMT may therefore improve diagnostic and therapeutic options. Traditionally, EMT is thought to be regulated by SNAIL, TWIST, and ZEB transcription factors. Since this view is increasingly challenged, we aimed to examine the importance of traditional EMT regulators while identifying alternative factors potentially orchestrating EMT. By combining computational analyses of epigenomic and transcriptomic data with loss-of-function experiments, we demonstrate that JUNB, a component of the AP-1 transcription factor complex, is crucial for EMT in the MCF10A mammary epithelial cell line model, but not SNAIL proteins and ZEB1. We exploited the JUNB-dependence of EMT to define a gene signature which is controlled by TGFβ in multiple cancer entities and which is predictive of patient survival. Our results provide a more refined picture of the dynamic regulation of EMT and suggest that traditional models for EMT regulation may need to be revised. Epithelial-mesenchymal transition (EMT) fosters cancer cell invasion and metastasis, the main cause of cancer-related mortality. Growing evidence that SNAIL and ZEB transcription factors, typically portrayed as master regulators of EMT, may be dispensable for this process, led us to re-investigate its mechanistic underpinnings. For this, we used an unbiased computational approach that integrated time-resolved analyses of chromatin structure and differential gene expression, to predict transcriptional regulators of TGFβ1-inducible EMT in the MCF10A mammary epithelial cell line model. Bioinformatic analyses indicated comparatively minor contributions of SNAIL proteins and ZEB1 to TGFβ1-induced EMT, whereas the AP-1 subunit JUNB was anticipated to have a much larger impact. CRISPR/Cas9-mediated loss-of-function studies confirmed that TGFβ1-induced EMT proceeded independently of SNAIL proteins and ZEB1. In contrast, JUNB was necessary and sufficient for EMT in MCF10A cells, but not in A549 lung cancer cells, indicating cell-type-specificity of JUNB EMT-regulatory capacity. Nonetheless, the JUNB-dependence of EMT-associated transcriptional reprogramming in MCF10A cells allowed to define a gene expression signature which was regulated by TGFβ1 in diverse cellular backgrounds, showed positively correlated expression with TGFβ signaling in multiple cancer transcriptomes, and was predictive of patient survival in several cancer types. Altogether, our findings provide novel mechanistic insights into the context-dependent control of TGFβ1-driven EMT and thereby may lead to improved diagnostic and therapeutic options. [ABSTRACT FROM AUTHOR]

Melanoma tumors are highly metastatic partly due to the ability of melanoma cells to transition between invasive and proliferative states. However, the mechanisms underlying this plasticity are still not fully understood. To identify new epigenetic regulators of melanoma plasticity, we combined data mining, tumor models, proximity proteomics, and CUT&RUN sequencing. We focus on the druggable family of bromodomain epigenetic readers and identify TRIM28 as a new regulator of melanoma plasticity. We find that TRIM28 promotes the expression of pro‐invasive genes and that TRIM28 controls the balance between invasiveness and growth of melanoma cells. We demonstrate that TRIM28 acts via the transcription factor JUNB that directly regulates the expression of pro‐invasive and pro‐growth genes. Mechanistically, TRIM28 controls the expression of JUNB by negatively regulating its transcriptional elongation by RNA polymerase II. In conclusion, our results demonstrate that a TRIM28–JUNB axis controls the balance between invasiveness and growth in melanoma tumors and suggest that the bromodomain protein TRIM28 could be targeted to reduce tumor spread. Synopsis: TRIM28 controls JUNB transcription that in turn induces RAS signature genes and suppresses YAP1 signature genes. TRIM28 depletion therefore leads to higher JUNB expression followed by increased melanoma growth and decreased melanoma invasiveness. TRIM28 is highly expressed in aggressive melanoma tumors.TRIM28 negatively regulates the transcriptional elongation of JUNB.JUNB expression induces a switch from melanoma invasiveness to melanoma growth. [ABSTRACT FROM AUTHOR]

Simple Summary: Studies have shown that JUNB and CXCR4 contribute to cell proliferation, migration and invasion, hence claiming an important role in tumor progression and metastasis, in various cancer types, including lung cancer. We have previously reported that JUNB and CXCR4 are overexpressed in circulating and disseminated tumor cells from breast cancer patients and are correlated with worse survival. In the present study, we investigated the expression of JUNB and CXCR4 in circulating tumor cells (CTCs) of non-small-cell lung cancer and small-cell lung cancer patients and determined their clinical significance. Our results showed that both JUNB and CXCR4 were overexpressed in CTCs from lung cancer patients. Furthermore, both proteins were correlated with poor survival in non-small-cell lung cancer patients, while only CXCR4 was associated with worse survival in small-cell lung cancer patients, suggesting that JUNB and CXCR4 are potentially important prognostic biomarkers for lung cancer. In the present study, we evaluated the expression of JUNB and CXCR4 in circulating tumor cells (CTCs) of lung cancer patients and investigated whether these proteins have prognostic clinical relevance. Peripheral blood from 30 patients with non-small-cell lung cancer (NSCLC) was filtered using ISET membranes, and cytospins from 37 patients with small-cell lung cancer (SCLC) were analyzed using confocal and VyCAP microscopy. Both JUNB and CXCR4 were expressed in the vast majority of lung cancer patients. Interestingly, the phenotypic patterns differed between NSCLC and SCLC patients; the (CK+/JUNB+/CXCR4+) phenotype was present in 50% of NSCLC vs. 71% of SCLC patients. Similarly, the (CK+/JUNB+/CXCR4–) was present in 44% vs. 71%, the (CK+/JUNB–/CXCR4+) in 6% vs. 71%, and the (CK+/JUNB–/CXCR4–) phenotype in 38% vs. 84%. In NSCLC, the presence of ≥1 CTCs with the (CK+/JUNB+/CXCR4+) phenotype was associated with worse progression-free survival (PFS) (p = 0.007, HR = 5.21) while ≥2 with poorer overall survival (OS) (p < 0.001, HR = 2.16). In extensive stage SCLC patients, the presence of ≥4 CXCR4-positive CTCs was associated with shorter OS (p = 0.041, HR = 5.01). Consequently, JUNB and CXCR4 were expressed in CTCs from lung cancer patients, and associated with patients' survival, underlying their key role in tumor progression. [ABSTRACT FROM AUTHOR]

Endometriosis is a disease defined by the presence of abnormal endometrium at ectopic sites, causing pain and infertility in 10% of women. Mutations in the chromatin remodeling protein ARID1A (AT-rich interactive domain-containing protein 1A) have been identified in endometriosis, particularly in the more severe deep infiltrating endometriosis and ovarian endometrioma subtypes. ARID1A has been shown to regulate chromatin at binding sites of the Activator Protein 1 (AP-1) transcription factor, and AP-1 expression has been shown in multiple endometriosis models. Here, we describe a role for AP-1 subunit JUNB in promoting invasive phenotypes in endometriosis. Through a series of knockdown experiments in the 12Z endometriosis cell line, we show that JUNB expression in endometriosis promotes the expression of epithelial-to-mesenchymal transition genes co-regulated by ARID1A including transcription factors SNAI1 and SNAI2, cell adhesion molecules ICAM1 and VCAM1, and extracellular matrix remodelers LOX and LOXL2. In highly invasive ARID1A-deficient endometriotic cells, co-knockdown of JUNB is sufficient to suppress invasion. These results suggest that AP-1 plays an important role in the progression of invasive endometriosis, and that therapeutic inhibition of AP-1 could prevent the occurrence of deep infiltrating endometriosis. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests that trehalose, a non-reducing disaccharide, ameliorates disease phenotypes by activating autophagy in animal models of various human diseases, including neurodegenerative diseases. Multiple in vitro studies suggest that activation of transcription factor EB, a master regulator of lysosomal biogenesis and autophagy genes, is a major contributor to trehalose-induced autophagy at later stages of exposure. However, underlying causes of trehalose-induced autophagy possibly occur at the early stage of the exposure period. In this study, we investigated the effects of short-term exposure of HeLa cells to trehalose on several signal transduction pathways to elucidate the initial events involved in its beneficial effects. Phospho-protein array analysis revealed that trehalose decreases levels of phosphorylated c-Jun, a component of the transcription factor activator protein-1, after 6 h. Trehalose also rapidly reduced mRNA expression levels of c-Jun and JunB, a member of the Jun family, within 1 h, resulting in a subsequent decrease in their protein levels. Future studies, exploring the interplay between decreased c-Jun and JunB protein levels and beneficial effects of trehalose, may provide novel insights into the mechanisms of trehalose action. [ABSTRACT FROM AUTHOR]

Background: Increased Galectin 3-binding protein (LGALS3BP) serum levels have been used to assess hepatic fibrosis stages and the severity of hepatocellular carcinoma (HCC). Considering the crucial role of transforming growth factor-β1 (TGF-β1) in the emergence of these diseases, the present study tested the hypothesis that LGALS3BP regulates the TGF-β1 signaling pathway., Methods: The expression levels of LGALS3BP and TGFB1 were analyzed in patients with metabolic dysfunction-associated steatohepatitis (MASH) and HCC. Multiple omics techniques, such as RNA-sequencing, transposase-accessible chromatin-sequencing assay, and liquid chromatography-tandem mass spectrometry proteomics, were used to identify the regulatory mechanisms for the LGALS3BP-TGF-β1 axis. The effects of altered TGF-β1 signaling by LGALS3BP were investigated in conditional LGALS3BP-knockin and LGALS3BP-knockout mice., Results: In patients with MASH and HCC, the levels of LGALS3BP and TGFB1 exhibited positive correlations. Stimulation of LGALS3BP by the inflammatory cytokine interferon α in HCC cells or ectopic overexpression of LGALS3BP in hepatocytes promoted the expression levels of TGFB1. Aggravated fibrosis was observed in the livers of hepatocyte-specific LGALS3BP-knockin mice, with increased TGFB1 levels. LGALS3BP directly bound to and assembled integrin αV, an integral mediator required for releasing active TGF-β1 from extracellular latent complex with the rearranged F-actin cytoskeleton. The released TGF-β1 activated JunB transcription factor, which in turn promoted the TGF-β1 positive feedback loop. LGALS3BP deletion in the hepatocytes downregulated TGF-β1 signaling and CCl 4 induced fibrosis. Moreover, LGALS3BP depletion hindered hepatocarcinogenesis by limiting the availability of fibrogenic TGF-β1., Conclusion: LGALS3BP plays a crucial role in hepatic fibrosis and carcinogenesis by controlling the TGF-β1 signaling pathway, making it a promising therapeutic target in TGF-β1-related diseases., (© 2024 The Author(s). Cancer Communications published by John Wiley & Sons Australia, Ltd on behalf of Sun Yat‐sen University Cancer Center.)

We have recently demonstrated that fibroblast growth factor receptor 2 (FGFR2)-mediated signalling alters progesterone receptor (PR) activity and response of oestrogen receptor a (ER)-positive (ER+) breast cancer (BCa) cell lines to anti-ER agents. Little is known about whether the crosstalk between ER and PR, shown to be modulated by the hormonal background, might also be affected by FGFR2. Here, PR-dependent behaviour of ER+ BCa cells was studied in the presence of oestrogen (E2) and progesterone (P4) and/or FGF7. In vitro analyses showed that FGF7/FGFR2 signalling: (a) abolished the effect of P4 on E2-promoted 3D cell growth and response to tamoxifen; (b) regulated ER and PR expression and activity; (c) increased formation of ER--PR complexes; and (d) reversed P4-triggered deregulation of ER-dependent genes. Analysis of clinical data demonstrated that the prognostic value of FGFR2 varied between patients with different menopausal status; that is, high expression of FGFR2 was significantly associated with longer progressionfree survival (PFS) in postmenopausal patients, whereas there was no significant association in premenopausal patients. FGFR2 was found to positively correlate with the expression of JunB proto-oncogene, AP-1 transcription factor subunit (JUNB), an ER-dependent gene, only in premenopausal patients. Molecular analyses revealed that the presence of JunB was a prerequisite for FGFR2-mediated abrogation of P4-induced inhibition of cell growth. Our results demonstrate for the first time that the FGF7/FGFR2--JunB axis abolishes the modulatory effects of PR on ER-associated biological functions in premenopausal ER+ BCa. This may provide foundations for a better selection of patients for FGFR-targeting therapeutic strategies. [ABSTRACT FROM AUTHOR]

Background: Diabetic foot ulcer (DFU) is a severe complication characterized by lowgrade infectious inflammation and probably associated with specific competitive endogenous RNAs (ceRNAs) and infiltrating immune cells. Nonetheless, no reliable biomarkers are used for detecting infectious inflammation in DFU. Therefore, it is essential to explore potential biomarkers for the accurate diagnosis and treatment of DFU. Methods: The gene expression profile was retrieved from Gene Expression Omnibus (GEO) database and divided into two groups, namely, standard samples and DFU samples. To establish the ceRNA networks, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were utilized to analyze differential expression genes (DEGs). The cell type identification was achieved by estimating relative subsets of RNA transcripts (CIBERSORT) algorithm to screen-specific immune-infiltrating cells associated with DFU. Results: A ceRNA network was constructed with 20 differential expression circRNA (DEcircRNAs), 11 differential expression microRNAs (DEmiRNAs), and 9 differential expression mRNAs (DEmRNAs). Functional enrichment analysis demonstrated that DFU was mainly enriched in vascular endothelial growth factor (VEGF) and T-cell receptor signaling. In addition, CIBERSORT estimation indicated that CD8+ T cells and Monocytes were significantly related to the expression of IL-6, a DFU-specific infectious inflammation factor. Conclusion: This study identified that some significant ceRNAs (JUNB, GATA3, hsa-circ-0049271 and hsa-circ-0074559) and infiltrating immune cells (CD8+ T cells and monocytes) might be related to DFU infectious inflammation. [ABSTRACT FROM AUTHOR]

Activating transcription factor 4 (ATF4) is known to play an important role in cerebral ischemia through apoptosis and neuron regulation. Histone demethylase JMJD3, specifically removing the methylation of H3K27me3, is highlighted to attenuate cerebral ischemic injury. However, few studies have explored the interaction between ATF4 and JMJD3 in this disease. Thus, we intended to explore the effect of ATF4 on cerebral ischemia. We first constructed a mouse model of middle cerebral artery occlusion (MCAO) and cultured PC12 cells. Specifically, the regulatory function of ATF4 and demethylase JMJD3 on the ischemic injury was explored via using ectopic expression and depletion by determination of modified neurologic severity score, blood–brain barrier, brain water content, apoptosis, infarct size, oxidative stress, and inflammation. Moreover, the interaction among ATF4, JUNB, JMJD3, and ETS1 was assessed by western blot analysis, immunofluorescence, immunoprecipitation, and dual‐luciferase reporter gene assay. These data showed that ATF4 and JMJD3 were upregulated in the MCAO model and PC12 cells. In addition, ectopic expression of ATF4 aggravated the ischemic injury through demethylation of JMJD3. Meanwhile, JMJD3 upregulated JUNB expression by inhibiting H3K21me2/3 enrichment and promoted ETS1 expression as well. Altogether, ATF4 could exacerbate cerebral ischemic injury through JMJD3‐dependent upregulation of JUNB/ETS1 expression, suggesting a potential theoretical basis of treatment for cerebral ischemic injury. [ABSTRACT FROM AUTHOR]

Clonal expansion and differentiation of various T helper subsets, such as Th1, Th2, and Th17 cells, depend on a complex of transcription factors, IRF4 and a BATF-containing AP-1 heterodimer. A major BATF heterodimeric partner, JunB, regulates Th17 differentiation, but the role of JunB in other T helper subsets is not well understood. Here we demonstrate that JunB is required for clonal expansion of Th1, Th2 and Th17 cells. In mice immunized with lipopolysaccharide (LPS), papain, or complete Freund's adjuvant (CFA), which induce predominantly Th1, Th2 and Th17 cells, respectively, accumulation of antigen-primed, Junb -deficient CD4+ T cells is significantly impaired. TCR-stimulated Junb -deficient CD4+ T cells are more sensitive to apoptosis, although they showed largely normal proliferation and cellular metabolism. JunB directly inhibits expression of genes involved in apoptosis, including Bcl2l11 (encoding Bim), by promoting IRF4 DNA binding at the gene locus. Taken together, JunB serves a critical function in clonal expansion of diverse T helper cells by inhibiting their apoptosis. [ABSTRACT FROM AUTHOR]

Background: Immunosuppressive cell interactions are responsible for tumor progression and metastasis, as well as anti-tumor immune dysfunction. However, the communication pattern remains unclear. Methods: We first integrated two single-cell RNA-seq datasets (GSE72056 and GSE103322) of different tumor types to increase the diversity of immunosuppressive cells. Then, based on the analysis results of the communication network, gene regulatory network (GRN), and highly activated pathways, we identified the hub gene in the immunosuppressive tumor microenvironment (TME). To further explore the molecular features of the identified gene, we performed several in silico analysis and in vitro experiments including qRT-PCR and CCK-8 assay. Results: Four types of immunosuppressive cells were identified, including cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), and regulatory T cells (Tregs). Based on GRNs and the interactions of immunosuppressive cells and tumor cells, we constructed an intercellular communication signature that divided the pan-cancer TME into two clusters with distinct immunological features and different responses to immunotherapy. In combination with pathway analysis, JunB proto-oncogene (JUNB) was identified as the hub gene of the immunosuppressive TME, and it designed a non-inflamed TME of bladder cancer according to evidence that JUNB was negatively correlated with immunomodulators, chemokines, major histocompatibility complex molecules, immune cell infiltration abundances, anti-cancer immune response, and immune checkpoint inhibitors. Moreover, JUNB may predict an unfavorable response to immunotherapy. The signaling network of the four types of cells demonstrated the dominant roles of CAFs and TAMs in the TME. Further investigation uncovered that the complement signal was highly activated in the interactions between subpopulations of the inflammatory phenotype of CAFs and TAMs. Functional experiment results demonstrated the upregulated JUNB in bladder cancer tissues and low-immunity-score tissues. In addition, CAFs showed a pro-tumor proliferation effect via JUNB. Conclusion: Our findings gave insights into the immunosuppressive TME communication network and provided potential therapeutic targets. [ABSTRACT FROM AUTHOR]

JunB, a component of the activator protein-1 (AP-1) transcription factor, is known to exhibit an important role in bone formation and bone marrow cell proliferation. During T helper type 2 (Th2) cell differentiation, JunB contributes to the regulation of interleukin (IL)-4 expression, and AP-1 and nuclear factor of activated T cell (NFAT) constitute a heteromer and contribute to IL-2 production. However, the role of JunB in other T cells has not been investigated. In 2017, it was revealed that JunB, in collaboration with basic leucine zipper ATF-like transcription factor (BATF), regulates the expression of Th17-related genes. Furthermore, JunB was found to play an important role in regulatory T (Treg) cell differentiation, contributing to CD25 expression and IL-2 production. IL-2 is a T cell activator and has been shown as a necessary factor for Treg proliferation. Here, we review the role of JunB in T cells based on basic research data and discuss the potential for its clinical applications.

Ischemic/reperfusion (IR) can cause adverse reactions including apoptosis, oxidative stress, and inflammation, but the existing therapeutic strategies have been limited. Moreover, the regulation of microglia plays an important role in brain injury after reperfusion. Hence, it is imperative to find new and effective drugs for modulating microglia to treat IR brain injury. Cyclic peptide compound cyclo-(Phe-Tyr) (Sparganin C, SC) is a compound isolated from Sparganii Rhizoma. However, the protective effects of SC on the central nervous system are rather unclear. In an attempt to elucidate the protective effects and mechanism of SC on cerebral damage induced by the IR, we used a middle cerebral artery occlusion reperfusion (MCAO/R) model in rats and discovered that SC significantly decreased the size of cerebral infarcts, improved neurological scores, and blocked inflammatory and oxidative factor release. Using RNA-Seq and metabolomics association analyses, SC was shown to have a protective impact through the JUNB and SOX5-related pathways. Metabolomic analysis revealed twenty-eight differentially expressed biomarkers. In addition, the detection of SC content in brain tissue using LC/MS revealed that SC had blood-brain barrier penetration. To investigate the mechanism, we established an in vitro BV2 cell oxygen-glucose deprivation/reperfusion (OGD/R) model and used siRNA as well as an inhibitor. The protective effects of SC were dependent on the JUNB and SOX5 to inhibit inflammation and apoptosis in microglia. Our findings revealed for the first that SC against IR injury by reducing inflammation and apoptosis while simultaneously acting as potential therapeutic lead compound for ischemic stroke.

Clonal expansion and differentiation of various T helper subsets, such as Th1, Th2, and Th17 cells, depend on a complex of transcription factors, IRF4 and a BATF-containing AP-1 heterodimer. A major BATF heterodimeric partner, JunB, regulates Th17 differentiation, but the role of JunB in other T helper subsets is not well understood. Here we demonstrate that JunB is required for clonal expansion of Th1, Th2 and Th17 cells. In mice immunized with lipopolysaccharide (LPS), papain, or complete Freund’s adjuvant (CFA), which induce predominantly Th1, Th2 and Th17 cells, respectively, accumulation of antigen-primed, Junb-deficient CD4+ T cells is significantly impaired. TCR-stimulated Junb-deficient CD4+ T cells are more sensitive to apoptosis, although they showed largely normal proliferation and cellular metabolism. JunB directly inhibits expression of genes involved in apoptosis, including Bcl2l11 (encoding Bim), by promoting IRF4 DNA binding at the gene locus. Taken together, JunB serves a critical function in clonal expansion of diverse T helper cells by inhibiting their apoptosis.

Background: Immunosuppressive cell interactions are responsible for tumor progression and metastasis, as well as anti-tumor immune dysfunction. However, the communication pattern remains unclear.Methods: We first integrated two single-cell RNA-seq datasets (GSE72056 and GSE103322) of different tumor types to increase the diversity of immunosuppressive cells. Then, based on the analysis results of the communication network, gene regulatory network (GRN), and highly activated pathways, we identified the hub gene in the immunosuppressive tumor microenvironment (TME). To further explore the molecular features of the identified gene, we performed several in silico analysis and in vitro experiments including qRT-PCR and CCK-8 assay.Results: Four types of immunosuppressive cells were identified, including cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), and regulatory T cells (Tregs). Based on GRNs and the interactions of immunosuppressive cells and tumor cells, we constructed an intercellular communication signature that divided the pan-cancer TME into two clusters with distinct immunological features and different responses to immunotherapy. In combination with pathway analysis, JunB proto-oncogene (JUNB) was identified as the hub gene of the immunosuppressive TME, and it designed a non-inflamed TME of bladder cancer according to evidence that JUNB was negatively correlated with immunomodulators, chemokines, major histocompatibility complex molecules, immune cell infiltration abundances, anti-cancer immune response, and immune checkpoint inhibitors. Moreover, JUNB may predict an unfavorable response to immunotherapy. The signaling network of the four types of cells demonstrated the dominant roles of CAFs and TAMs in the TME. Further investigation uncovered that the complement signal was highly activated in the interactions between subpopulations of the inflammatory phenotype of CAFs and TAMs. Functional experiment results demonstrated the upregulated JUNB in bladder cancer tissues and low-immunity-score tissues. In addition, CAFs showed a pro-tumor proliferation effect via JUNB.Conclusion: Our findings gave insights into the immunosuppressive TME communication network and provided potential therapeutic targets.

Preeclampsia (PE) is a complex disorder affecting pregnant women, leading to significant maternal and fetal morbidity and mortality. Understanding the cellular dynamics and molecular mechanisms underlying PE is crucial for developing effective therapeutic strategies. This study utilized single-cell RNA sequencing (scRNA-seq) to delineate the cellular landscape of the placenta in PE, identifying 11 distinct cell subpopulations, with macrophages playing a pivotal role in mediating cell-cell communication. Specifically, the transcription factor JUNB was found to be a key gene in macrophages from PE samples, influencing the interaction between macrophages and both epithelial and endothelial cells. Functional experiments indicated that interference with JUNB expression promoted macrophage polarization towards an M2 phenotype, which facilitated trophoblast invasion, migration, and angiogenesis. Mechanistically, JUNB regulated the MIIP/PI3K/AKT pathway, as evidenced by gene expression analysis following JUNB knockdown. The study further demonstrated that targeting JUNB could activate the PI3K/AKT pathway by transcriptionally activating MIIP, thus promoting M2 polarization and potentially delaying the onset of PE. These findings present new insights into the pathogenesis of PE and suggest a novel therapeutic approach by modulating macrophage polarization. • This study identified 11 distinct cell subpopulations in preeclampsia (PE). • The study found JUNB to be a key gene in macrophages within PE. • It demonstrated that interference with JUNB expression could promote macrophage polarization towards an M2 phenotype. • The study revealed that JUNB affects PE through the MIIP/PI3K/AKT pathway. • A new strategy was proposed to potentially delay the onset of PE by targeting JUNB. [ABSTRACT FROM AUTHOR]

Regulation of ROS metabolism plays a major role in cellular adaptation to oxidative stress in cancer cells, but the molecular mechanism that regulates catalase, a key antioxidant enzyme responsible for conversion of hydrogen peroxide to water and oxygen, remains to be elucidated. Therefore, we investigated the transcriptional regulatory mechanism controlling catalase expression in three human mammary cell lines: the normal mammary epithelial 250MK primary cells, the breast adenocarcinoma MCF-7 cells and an experimental model of MCF-7 cells resistant against oxidative stress resulting from chronic exposure to H2O2 (Resox), in which catalase was overexpressed. Here we identify a novel promoter region responsible for the regulation of catalase expression at -1518/-1226 locus and the key molecules that interact with this promoter and affect catalase transcription. We show that the AP-1 family member JunB and retinoic acid receptor alpha (RARα) mediate catalase transcriptional activation and repression, respectively, by controlling chromatin remodeling through a histone deacetylases-dependent mechanism. This regulatory mechanism plays an important role in redox adaptation to chronic exposure to H2O2 in breast cancer cells. Our study suggests that cancer adaptation to oxidative stress may be regulated by transcriptional factors through chromatin remodeling, and reveals a potential new mechanism to target cancer cells.

Background and Aims: The regenerative capacity of the pancreas diminishes with age. Understanding acinar cell responses to injury and the resolution of regenerative processes is crucial for tissue homeostasis. However, knowledge about the impact of aging on these processes remains limited., Methods: To investigate the influence of aging on pancreas regeneration, we established a cohort of young (7-14 weeks) and old (18 months) C57bl/6 mice. Experimental pancreatitis was induced using caerulein, and pancreas samples were collected at various time points after induction, covering acute damage response, inflammation, peak proliferation, and inflammation resolution. Our analysis involved immunohistochemistry, quantitative imaging, and gene expression analyses., Results: Our study revealed a significant decline in the regenerative capacity of the pancreas in old mice. Despite similar morphology and transcriptional profiles between the pancreas of young and old mice under homeostasis, the aged pancreas is primed to generate an exacerbated proinflammatory reaction in response to injury. Specifically, we observed notable upregulation of Junb expression in acinar cells and aberrant myofibroblast activation in the aged pancreas., Conclusion: The response of acinar cells to injury in the pancreas of aged mice is characterized by an increased susceptibility to inflammation and stromal reactions. Our findings uncover a pre-existing proinflammatory state in aged acinar cells, offering insights into potential strategies to prevent the onset of pancreatic insufficiency and the development of inflammatory conditions. These insights hold implications for preventing conditions such as chronic pancreatitis and pancreatic ductal adenocarcinoma., (© 2024 The Authors.)

JunB, a component of the activator protein-1 (AP-1) transcription factor, is known to exhibit an important role in bone formation and bone marrow cell proliferation. During T helper type 2 (Th2) cell differentiation, JunB contributes to the regulation of interleukin (IL)-4 expression, and AP-1 and nuclear factor of activated T cell (NFAT) constitute a heteromer and contribute to IL-2 production. However, the role of JunB in other T cells has not been investigated. In 2017, it was revealed that JunB, in collaboration with basic leucine zipper ATF-like transcription factor (BATF), regulates the expression of Th17-related genes. Furthermore, JunB was found to play an important role in regulatory T (Treg) cell differentiation, contributing to CD25 expression and IL-2 production. IL-2 is a T cell activator and has been shown as a necessary factor for Treg proliferation. Here, we review the role of JunB in T cells based on basic research data and discuss the potential for its clinical applications. [ABSTRACT FROM AUTHOR]

Activation of macrophages is a key step in the initiation of immune responses, but the transcriptional mechanisms governing macrophage activation during infection are not fully understood. It was recently shown that the AP-1 family transcription factor JUNB positively regulates macrophage activation in response to Toll-like receptor agonists that promote classical or M1 polarization, as well as to the cytokine interleukin-4 (IL-4), which elicits an alternatively activated or M2 phenotype. However, a role for JUNB in macrophage activation has never been demonstrated in vivo. Here, to dissect the role of JUNB in macrophage activation in a physiological setting, mice lacking JUNB specifically in myeloid cells were tested in two infection models: experimental cerebral malaria, which elicits a pathological type 1 immune response, and helminth infection, in which type 2 responses are protective. Myeloid-restricted deletion of Junb reduced type 1 immune activation, which was associated with reduced cerebral pathology and improved survival during infection with Plasmodium berghei. Myeloid JUNB deficiency also compromised type 2 activation during infection with the hookworm Nippostrongylus brasiliensis, leading to diminished cytokine production and eosinophil recruitment and increased parasite burden. These results demonstrate that JUNB in myeloid cells shapes host responses and outcomes during type 1 and type 2 infections.

Abstract Background Circulating tumor cells (CTCs) are important for metastatic dissemination of cancer. They can provide useful information, regarding biological features and tumor heterogeneity; however, their detection and characterization are difficult due to their limited number in the bloodstream and their mesenchymal characteristics. Therefore, new biomarkers are needed to address these questions. Methods Bioinformatics functional enrichment analysis revealed a subgroup of 24 genes, potentially overexpressed in CTCs. Among these genes, the chemokine receptor CXCR4 plays a central role. After prioritization according to the CXCR4 corresponding pathways, five molecules (JUNB, YWHAB, TYROBP, NFYA, and PRDX1) were selected for further analysis in biological samples. The SKBR3, MDA-MB231, and MCF7 cell lines, as well as PBMCs from normal (n = 10) blood donors, were used as controls to define the expression pattern of all the examined molecules. Consequently, 100 previously untreated metastatic breast cancer (mBC) patients (n = 100) were analyzed using the following combinations of antibodies: CK (cytokeratin)/CXCR4/JUNB, CK/NFYA/ΥWHΑΒ (14-3-3), and CK/TYROBP/PRDX1. A threshold value for every molecule was considered the mean expression in normal PBMCs. Results Quantification of CXCR4 revealed overexpression of the receptor in SKBR3 and in CTCs, following the subsequent scale (SKBR3>CTCs>Hela>MCF7>MDA-MB231). JUNB was also overexpressed in CTCs (SKBR3>CTCs>MCF7>MDA-MB231>Hela). According to the defined threshold for each molecule, CXCR4-positive CTCs were identified in 90% of the patients with detectable tumor cells in their blood. In addition, 65%, 75%, 14.3%, and 12.5% of the patients harbored JUNB-, TYROBP-, NFYA-, and PRDX-positive CTCs, respectively. Conversely, none of the patients revealed YWHAB-positive CTCs. Interestingly, JUNB expression in CTCs was phenotypically and statistically enhanced compared to patients’ blood cells (p = 0.002) providing a possible new biomarker for CTCs. Furthermore, the detection of JUNB-positive CTCs in patients was associated with poorer PFS (p = 0.015) and OS (p = 0.002). Moreover, JUNB staining of 11 primary and 4 metastatic tumors from the same cohort of patients revealed a dramatic increase of JUNB expression in metastasis. Conclusions CXCR4, JUNB, and TYROBP were overexpressed in CTCs, but only the expression of JUNB was associated with poor prognosis, providing a new biomarker and a potential therapeutic target for the elimination of CTCs.

Background: Nowadays, different clinical behaviors of odontogenic cysts, little information about their biological agents, importance of diagnosis, and early diagnosis of these lesions have encouraged the researchers to conduct new studies. JunB acts as a regulator of vascular endothelial growth factor (VEGF) protein production and affects vessel proliferation and tissue angiogenesis. Hence, this study was conducted to compare angiogenesis through VEGF and JunB expression in odontogenic keratocysts (OKCs) and dentigerous cysts (DCs). Materials and Methods: A total of 25 paraffin blocks of OKCs and 25 DCs were included in this experimental descriptive cross-sectional study, and immunohistochemical expression of VEGF and JunB was evaluated. Percentage and score of expression were recorded for each sample, and independent t-test, Mann–Whitney U, and Spearman statistical tests were run to analyze the data. The statistical significance level was set at

Background: Krüppel–like factor 10 (KLF10) belongs to the Sp1-like transcription factor family, which plays an important role in many directions, e.g., cell proliferation, apoptosis, and differentiation. Its 5′ upstream regions are conserved across mammalian species. However, the regulatory mechanism has not been elucidated yet. Objective: Nonetheless the basal transcriptional regulation mechanisms of these regions are unknown. Here, we characterized it which is indispensable for the basal transcription of the Klf10 gene. Methods: Seven deletions of 5′ upstream DNA fragments from the 10 kb mKlf10 genomic DNA were produced by PCR and cloned into the upstream of the luciferase (Luc) reporter gene in the pGL3 basic plasmid. Result: The luciferase reporter assay showed that the DNA sequence at positions from −101 to +68 was required for a principle activity in the promoter of mKlf10 gene, in which transcriptional factor binding motifs, one JunB and two Sp1 sites, are included. Mutations at the sequence of JunB motif, but not at the two Sp1, abrogated the promoter activity completely, suggesting the indispensable role of JunB site for basal transcription of mKlf10 gene. Moreover, electrophoretic mobility and supershift assays (EMSA) uncovered that JunB protein bound to this region specifically. Conclusion: Taken together, our study revealed that the JunB but not Sp1 at mKlf10 promoter functions as a positive basic factor for the transcriptional activity of the gene. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a heterogeneous disease that is extremely hard to cure owing to its complex regulation network of pathogenesis, especially cartilage degeneration. FBXO21 is a subunit of ubiquitin E3 ligases that degrades P‐glycoprotein and EID1 by ubiquitination and activates the JNK and p38 pathways; however, its role in OA remains unknown. Here, the main objective of this study was to evaluate the potential effects and mechanism of FBXO21 in OA degeneration, we revealed that FBXO21 is upregulated in the cartilage of patients with OA, aging, and monosodium iodoacetate‐induced OA rats, and chondrocytes treated with interleukin‐1β, tumor necrosis factor‐α, and lipopolysaccharide. Moreover, the in vivo and in vitro knockdown of FBXO21 suppressed OA‐related cartilage degeneration, as evidenced by activated autophagy, upregulated anabolism, alleviated apoptosis, and downregulated catabolism. In contrast, its overexpression promoted OA‐related cartilage degeneration. In addition, using mass spectrometry and co‐immunoprecipitation assay, we demonstrated that the downstream mechanism of FBXO21 inhibits autophagy by interacting with and phosphorylating ERK. Furthermore, FBXO21 alleviated anabolism and enhanced apoptosis and catabolism by inhibiting autophagy in rat chondrocytes. Interestingly, for its upstream mechanism, JUNB promoted FBXO21 expression by directly targeting the FBXO21 promoter, thus further accelerating cartilage degeneration in SW1353 cells and rat chondrocytes. Overall, our findings reveal that the JUNB‐FBXO21‐ERK axis regulates OA apoptosis and cartilage matrix metabolism by inhibiting autophagy. Therefore, FBXO21 is an attractive target for regulating OA pathogenesis, and its knockdown may provide a novel targeted therapy for OA. [ABSTRACT FROM AUTHOR]

Proteasome inhibitor MG132 was shown to enhance the secretion of interleukin 8 (IL‐8) by various cells. The enhancement is regulated by the transcription factor activator protein‐1 (AP‐1) at the transcriptional level. AP‐1 is a dimer formed by AP‐1 family proteins. The purpose of the present study was to explore the combinations of the AP‐1 family proteins that contribute to MG132‐driven IL‐8 secretion. Oral squamous cell carcinoma‐derived cell lines, Ca9‐22 and HSC3, were used to demonstrate their response to MG132. IL‐8 secretion was augmented by MG132 in both cell lines. c‐Jun expression was detected in both the cell lines, whereas c‐Fos expression was detected only in the HSC3. The influence of MG132 stimulation on c‐Jun and c‐Fos expression was further examined by western blot analysis. c‐Jun expression was increased by MG132 stimulation, whereas c‐Fos expression was not detected even after MG132 stimulation. As JunB is reported to inhibit the transcriptional activity of the AP‐1 complex, we speculated that the c‐Jun homodimer should contribute to IL‐8 enhancement. Expression vectors encoding wild type and c‐Jun mutants, M17 and M22‐23, respectively, were constructed and transfected into the Ca9‐22 cells. In contrast to our expectations, MG132‐induced IL‐8 secretion was significantly reduced in all the transfectants suggesting that other c‐Jun members might form homodimers with c‐Jun and contribute to IL‐8 enhancement. Transfection of the cells with c‐Jun or JunB small hairpin RNA (shRNA) reduced IL‐8 secretion up to 50% and 65% of the control shRNA transfectant. Furthermore, cotransfection of both shRNA almost completely inhibited the IL‐8 secretion. These results indicate that JunB not only inhibits but also enhances the transcription of c‐Jun targets in combination with c‐Jun. [ABSTRACT FROM AUTHOR]

Endothelial damage is the initial and crucial factor in the occurrence and development of vascular complications in diabetic patients, contributing to morbidity and mortality. Although hyperglycemia has been identified as a damaging effector, the detailed mechanisms remain elusive. In this study, identified by ATAC-seq and RNA-seq, JunB reverses the inhibition of proliferation and the promotion of apoptosis in human umbilical vein endothelial cells treated with high glucose, mainly through the cell cycle and p53 signaling pathways. Furthermore, JunB undergoes phase separation in the nucleus and in vitro, mediated by its intrinsic disordered region and DNA-binding domain. Nuclear localization and condensation behaviors are required for JunB-mediated proliferation and apoptosis. Thus, our study uncovers the roles of JunB and its coacervation in repairing vascular endothelial damage caused by high glucose, elucidating the involvement of phase separation in diabetes and diabetic endothelial dysfunction., (© The Author(s) (2023). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, CEMCS, CAS.)

The transcription factor JunB can induce physiological or pathological responses to various stimuli, including immune stimulants and bacteria, and plays an important role in the immune response process. In this study, we identified a JunB family member in Schizothorax prenanti (S. prenanti), which was designated SpJunB. The complete coding sequence (CDS) of SpJunB was 930 bp in length, which was submitted to GenBank (ID: MN215886). SpJunB encodes a putative protein of 309 amino acids, which is highly homologous to JunB of common carp. The SpJunB protein contained a conserved JunB domain, and its 3D structure was also highly similar to (77.61%) the human SpJunB protein. SpJunB was found to be extensively expressed in various tissues, with the highest expression in the spleen. The expression of SpJunB was significantly upregulated after Aeromonas hydrophila (A. hydrophila) challenge. Prokaryotic expression indicated that a 51 kDa recombinant protein was obtained after induction with 1.5 mmol/L isopropyl-beta-D-thiogalactopyranoside (IPTG) for 6 h at 37 °C. The expression levels of IL -1β, IL -6 and IL -8 were significantly upregulated (p < 0.01) after treatment of S. prenanti with the SpJunB protein. The activities of SOD, AKP and LZM were also significantly increased (p < 0.01) after the treatment of S. prenanti with the SpJunB protein. Simultaneously, the SpJunB protein reduced the infection rate of A. hydrophila in S. prenanti. In conclusion, SpJunB may improve the immune functions of S. prenanti. It will be beneficial to further study the immune mechanism of JunB in fish. [ABSTRACT FROM AUTHOR]

Tumor‐associated macrophages (TAMs) are vital constituents in mediating cell‐to‐cell communication within the tumor microenvironment. However, the molecular mechanisms underlying the interplay between TAMs and tumor cells that guide cell fate are largely undetermined. Extracellular vesicles, also known as exosomes, which are derived from TAMs, are the components exerting regulatory effects. Thus, understanding the underlying mechanism of "onco‐vesicles" is of crucial importance for prostate cancer (PCa) therapy. In this study, we analyzed micro RNA sequences in exosomes released by THP‐1 and M2 macrophages and found a significant increase in miR‐95 levels in TAM‐derived exosomes, demonstrating the direct uptake of miR‐95 by recipient PCa cells. In vitro and in vivo loss‐of‐function assays suggested that miR‐95 could function as a tumor promoter by directly binding to its downstream target gene, JunB, to promote PCa cell proliferation, invasion, and epithelial–mesenchymal transition. The clinical data analyses further revealed that higher miR‐95 expression results in worse clinicopathological features. Collectively, our results demonstrated that TAM‐mediated PCa progression is partially attributed to the aberrant expression of miR‐95 in TAM‐derived exosomes, and the miR‐95/JunB axis provides the groundwork for research on TAMs to further develop more‐personalized therapeutic approaches for patients with PCa. [ABSTRACT FROM AUTHOR]

Capsaicin and zinc have recently been highlighted as potential treatments for glucose metabolism disorders; however, the effect of these two natural compounds on signalling pathways involved in glucose metabolism is still uncertain. In this study, we assessed the capsaicin- or zinc- induced activation of signalling molecules including calcium/calmodulin-dependent protein kinase 2 (CAMKK2), cAMP-response element-binding protein (CREB), and target of rapamycin kinase complex 1 (TORC1). Moreover, the expression status of genes associated with the control of glucose metabolism was measured in treated cells. The activation of cell signalling proteins was then evaluated in capsaicin- or zinc treated cells in the presence or absence of cell-permeant calcium chelator (BAPTA-AM) and the CAMKK inhibitor (STO-609). Finally, capsaicin- and zinc-induced glucose uptake was measured in the cells pre-treated with or without BAPTA-AM. Our results indicate that calcium flux induced by capsaicin or zinc led to activation of calcium signalling molecules and promoting glucose uptake in skeletal muscle cells. Pharmacological inhibition of CAMKK diminished activation of signalling molecules. Moreover, we observed an increase in intracellular cAMP levels in the cells after treatment with capsaicin and zinc. Our data show that capsaicin and zinc mediate glucose uptake in C2C12 skeletal muscle cells through the activation of calcium signalling.

Mesenchymal stem cells (MSCs) have been highlighted as promising candidate cells in relation to cutaneous wound healing. The current study aimed to investigate whether MSC‐derived extracellular vesicles (EVs) could transfer microRNA‐27b (miR‐27b) to influence cutaneous wound healing. The miR‐27b expression was examined in the established cutaneous wound mouse model, and its correlation with the wound healing rate was evaluated by Pearson's correlation analysis. The identified human umbilical cord MSC‐derived EVs were co‐cultured with human immortal keratinocyte line HaCaT and human skin fibroblasts (HSFs). The mice with cutaneous wound received injections of MSC‐derived EVs. The effects of EVs or miR‐27b loaded on wound healing and cellular functions were analysed via gain‐ and loss‐of‐function approaches in the co‐culture system. Dual‐luciferase reporter gene assay was employed to verify the relationship between miR‐27b and Itchy E3 ubiquitin protein ligase (ITCH). Rescue experiments were conducted to investigate the underlying mechanisms associated with the ITCH/JUNB/inositol‐requiring enzyme 1α (IRE1α) axis. miR‐27b was down‐regulated in the mouse model, with its expression found to be positively correlated with the wound healing rate. Abundant miR‐27b was detected in the MSC‐derived EVs, while EV‐transferred miR‐27b improved cutaneous wound healing in mice and improved proliferation and migration of HaCaT cells and HSFs in vitro. As a target of miR‐27b, ITCH was found to repress cell proliferation and migration. ITCH enhanced the JUNB ubiquitination and degradation, ultimately inhibiting JUNB and IRE1α expressions and restraining wound healing. Collectively, MSC‐derived EVs transferring miR‐27b can promote cutaneous wound healing via ITCH/JUNB/IRE1α signalling, providing insight with clinical implications. [ABSTRACT FROM AUTHOR]

Background: The chemokine receptor CXCR4 and the transcription factor JUNB, expressed on a variety of tumor cells, seem to play an important role in the metastatic process. Since disseminated tumor cells (DTCs) in the bone marrow (BM) have been associated with worse outcomes, we evaluated the expression of CXCR4 and JUNB in DTCs of primary, nonmetastatic breast cancer (BC) patients before the onset of any systemic treatment. Methods: Bilateral BM (10 ml) aspirations of 39 hormone receptor (HR)-positive, HER2-negative BC patients were assessed for the presence of DTCs using the following combination of antibodies: pan-cytokeratin (A45-B/B3)/CXCR4/JUNB. An expression pattern of the examined proteins was created using confocal laser scanning microscopy, Image J software and BC cell lines. Results: CXCR4 was overexpressed in cancer cells and DTCs, with the following hierarchy of expression: SKBR3 > MCF7 > DTCs > MDA-MB231. Accordingly, the expression pattern of JUNB was: DTCs > MDA-MB231 > SKBR3 > MCF7. The mean intensity of CXCR4 (6411 ± 334) and JUNB (27725.64 ± 470) in DTCs was statistically higher compared with BM hematopoietic cells (2009 ± 456, p = 0.001; and 11112.89 ± 545, p = 0.001, respectively). The (CXCR4+JUNB+CK+) phenotype was the most frequently detected [90% (35/39)], followed by the (CXCR4–JUNB+CK+) phenotype [36% (14/39)]. However, (CXCR4+JUNB–CK+) tumor cells were found in only 5% (3/39) of patients. Those patients harboring DTCs with the (CXCR4+JUNB+CK+) phenotype revealed lower overall survival (Cox regression: p = 0.023). Conclusions: (CXCR4+JUNB+CK+)-expressing DTCs, detected frequently in the BM of BC patients, seem to identify a subgroup of patients at higher risk for relapse that may be considered for close follow up. [ABSTRACT FROM AUTHOR]