Role of octamer transcription factor 4 in proliferation,migration,drug sensitivity,and stemness maintenance of pancreatic cancer cells

BACKGROUND Pancreatic cancer(PC)is one of the most aggressive malignancies characterized by rapid progression and poor prognosis.The involvement of cancer stem cells(CSCs)and Octamer transcription factor 4(OCT4)in PC pathobiology is being increasingly recognized.AIM To investigate the role of OCT4 in pancreatic CSCs and its effect on PC cell prolif-eration,migration,drug sensitivity,and stemness maintenance.METHODS We analyzed OCT4 and CD133 expression in PC tissues and cell lines.BxPC-3 cells were used to assess the effects of OCT4 modulation on cellular behavior.Proliferation,migration,and stemness of BxPC-3 cells were evaluated,and the PI3K/AKT/mTOR pathway was examined to gain mechanistic insights.RESULTS OCT4 and CD133 were significantly overexpressed in PC tissues.OCT4 mo-dulation altered BxPC-3 cell proliferation,invasion,and stemness,with OCT4 overexpression(OV-OCT4)enhancing these properties and OCT4 interference decreasing them.OV-OCT4 activated the PI3K/AKT/mTOR pathway,which correlated with an increase in PC stem cells(PCSC).CONCLUSION OCT4 plays a crucial role in PCSCs by influencing the aggressiveness and drug resistance of PC cells,thus presenting itself as a potential therapeutic target.

Psychiatric risk gene transcription factor 4 preferentially regulates cortical interneuron neurogenesis during early brain development

Genetic variants within or near the transcription factor 4 gene(TCF4)are robustly implicated in psychiatric disorders including schizophrenia.However,the biological pleiotropy poses considerable obstacles to dissect the potential relationship between TCF4 and those highly heterogeneous diseases.Through integrative transcriptomic analysis,we demonstrated that TCF4 is preferentially expressed in cortical interneurons during early brain development.Therefore,disruptions of interneuron development might be the underlying contribution of TCF4 perturbation to a range of neurodevelopmental disorders.Here,we performed chromatin immunoprecipitation sequencing(ChIP-seq)of TCF4 on human medial ganglionic eminence-like organoids(hMGEOs)to identify genome-wide TCF4 binding sites,followed by integration of multi-omics data from human fetal brain.We observed preferential expression of the isoform TCF4-B over TCF4-A.De novo motif analysis found that the identified 5916 TCF4 binding sites are significantly enriched for the E-box sequence.The predicted TCF4 targets in general have positively correlated expression levels with TCF4 in the cortical interneurons,and are primarily involved in biological processes related to neurogenesis.Interestingly,we found that TCF4 interacts with non-bHLH proteins such as FOS/JUN,which may underlie the functional specificity of TCF4 in hMGEOs.This study highlights the regulatory role of TCF4 in interneuron development and provides compelling evidence to support the biological rationale linking TCF4 to the developing cortical interneuron and psychiatric disorders.

Activating transcription factor 4 protects mice against sepsis-induced intestinal injury by regulating gut-resident macrophages differentiation

Background: Gut-resident macrophages (gMacs) supplemented by monocytes-to-gMacs differentiation play a critical role in maintaining intestinal homeostasis. Activating transcription factor 4 (ATF4) is involved in immune cell differentiation. We therefore set out to investigate the role of ATF4-regulated monocytes-to-gMacs differentiation in sepsis-induced intestinal injury.Methods: Sepsis was induced in C57BL/6 wild type (WT) mice andAtf4-knockdown (Atf4+/-) mice by cecal ligation and puncture or administration of lipopolysaccharide (LPS). Colon, peripheral blood mononuclear cells, sera, lung, liver, and mesenteric lymph nodes were collected for flow cytometry, hematoxylin and eosin staining, immunohistochemistry, quantitative reverse transcription polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively.Results: CD64, CD11b, Ly6C, major histocompatibility complex-II (MHC-II), CX3CR1, Ly6G, and SSC were identified as optimal primary markers for detecting the process of monocytes-to-gMacs differentiation in the colon of WT mice. Monocytes-to-gMacs differentiation was impaired in the colon during sepsis and was associated with decreased expression of ATF4 in P1 (Ly6Chi monocytes), the precursor cells of gMacs.Atf4 knockdown exacerbated the impairment of monocytes-to-gMacs differentiation in response to LPS, resulting in a significant reduction of gMacs in the colon. Furthermore, compared with WT mice,Atf4+/- mice exhibited higher pathology scores, increased expression of inflammatory factor genes (TNF-α, IL-1β), suppressed expression of CD31 and vascular endothelial-cadherin in the colon, and increased translocation of intestinal bacteria to lymph nodes and lungs following exposure to LPS. However, the aggravation of sepsis-induced intestinal injury resulting fromAtf4 knockdown was not caused by the enhanced inflammatory effect of Ly6Chi monocytes and gMacs.Conclusion: ATF4, as a novel regulator of monocytes-to-gMacs differentiation, plays a critical role in protecting mice against sepsis-induced intestinal injury, suggesting that ATF4 might be a potential therapeutic target for sepsis treatment.

WWP2 promotes degradation of transcription factor OCT4 in human embryonic stem cells

POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin （Ub）-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference （RNAi）, suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.

Tcf7l1 promotes transcription of Kruppel-like factor 4 during Xenopus embryogenesis

Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.

Pterygial body epithelium domination of pterygial proliferation with TCF4 as a potential key factor

AIM： To characterize the proliferative capacity of pterygial epithelium in different regions（head, neck and body） of pterygium and explore the function of transcription factor 4（TCF4） in pterygium proliferation.METHODS： Thirty pterygium tissues and 10 normal conjunctival tissues were obtained from Zhongshan Ophthalmic Center（ZOC） and Guangdong Eye Bank, respectively. Proliferative capacity of head, neck and body in pterygial epithelium was measured using clonal analysis, fold growth analysis and expression profile of proliferative markers revealed by immunofluorescent staining and real-time PCR. The expression of TCF4 was highlighted by double immunofluorescent staining with other proliferation related markers such as proliferating cell nuclear antigen（PCNA） and ATP-binding cassette subfamily G member 2（ABCG2）.RESULTS： The proliferative potential of pterygial epithelium was higher than that of normal conjunctival epithelium. High expression levels of proliferative markers（P63α, PCNA and ABCG2） in pterygial body epithelium were observed in immunofluorescent staining and real-time PCR（P〈0.05）. Also, epithelial cells isolated from pterygial body demonstrated higher proliferative capacity in clonal analysis and fold growth analysis, than those isolated from the head and neck regions. The TCF4 expression in pterygial epithelium was similar to other proliferative markers（P63α, PCNA and ABCG2）, as higher in pterygial body than head and neck. Moreover, TCF4 showed coexpression with other proliferation-related markers（PCNA and ABCG2） in the double immunofluorescent staining experiment.CONCLUSION： The proliferative capacity in pterygial body epithelium is prominent than the head and neck regions, and upregulated TCF4 may be associated with enhanced proliferation in the pterygium.

Bioinformatics analysis of microarray data to explore the key genes involved in HSF4 mutation-induced cataract

AIM： To reveal the mechanisms of heat-shock transcription factor 4 （HSF4） mutation-induced cataract.METHODS： GSE22362, including 3 HSF4-null lens and 3 wild-type lens, was obtained from Gene Expression Omnibus database. After data preprocessing, the differentially expressed genes （DEGs） were identified using the limma package. Based on Database for Annotation, Visualization and Integrated Discovery （DAVID） tool, functional and pathway enrichment analyses were performed for the DEGs. Followed by protein-protein interaction （PPI） network was constructed using STRING database and Cytoscape software. Furthermore, the validated microRNA （miRNA）-DEG pairs were obtained from miRWalk2.0 database, and then miRNA-DEG regulatory network was visualized by Cytoscape software. RESULTS： A total of 176 DEGs were identified in HSF4-null lens compared with wild-type lens. In the PPI network, FBJ osteosarcoma oncogene （FOS）, early growth response 1 （EGR1） and heme oxygenase （decycling） 1 （HMOX1） had higher degrees and could interact with each other. Besides, mmu-miR-15a-5p and mmu-miR-26a-5p were among the top 10 miRNAs in the miRNA-DEG regulatory network. Additionally, mmu-miR-26a-5p could target EGR1 in the regulatory network. CONCLUSION： FOS, EGR1, HMOX1, mmu-miR-26a-5p and mmu-miR-15a-5p might function in the pathogenesis of HSF4 mutation-induced cataract.

Methylation profile of bovine Oct4 gene coding region in relation to three germ layers

Previous studies have shown that octamer-binding transcription factor 4（Oct4） plays a significant role in early embryonic development of mammalian animals, and different Oct4 expression levels induce multi-lineage differentiation which are regulated by DNA methylation. To explore the relationship between the methylation pattern of Oct4 gene exon 1 and embryonic development, in this work, five different tissues（heart, liver, lung, cerebrum and cerebellum） from three germ layers were chosen from low age（50–60 d） and advanced age（60–70 d） of fetal cattle and the differences between tissues or ages were analyzed, respectively. The result showed that the DNA methylation level of Oct4 gene exon 1 was significant different（P〈0.01） between any two of three germ layers in low age（〈60 d）, but kept steady of advanced age（P〉0.05）（〉60 d）, suggesting that 60-d post coital was an important boundary for embryonic development. In addition, in ectoderm（cerebrum and cerebellum）, there was no significant methylation difference of Oct4 gene exon 1 between low age and advanced age（P〉0.05）, but the result of endoderm（liver and lung） and mesoderm（heart） were on the contrary（P〈0.01）, which indicated the development of ectoderm was earlier than endoderm and mesoderm. The methylation differences from the 3rd, 5th and 9th Cp G-dinucleotide loci of Oct4 gene exon 1 were significantly different between each two of three germ layers（P〈0.05）, indicating that these three loci may have important influence on bovine embryonic development. This study showed that bovine germ layers differentiation was significantly related to the DNA methylation status of Oct4 gene exon 1. This work firstly identified the DNA methylation profile of bovine Oct4 gene exon 1 and its association with germ layers development in fetus and adult of cattle. Moreover, the work also provided epigenetic information for further studying bovine embryonic development and cellular reprogramming.

Edaravone protects against oxygen-glucose-serum deprivation/restoration-induced apoptosis in spinal cord astrocytes by inhibiting integrated stress response

We previously found that oxygen-glucose-serum deprivation/restoration（OGSD/R） induces apoptosis of spinal cord astrocytes, possibly via caspase-12 and the integrated stress response, which involves protein kinase R-like endoplasmic reticulum kinase（PERK）, eukaryotic initiation factor 2-alpha（eIF2α） and activating transcription factor 4（ATF4）. We hypothesized that edaravone, a low molecular weight, lipophilic free radical scavenger, would reduce OGSD/R-induced apoptosis of spinal cord astrocytes. To test this, we established primary cultures of rat astrocytes, and exposed them to 8 hours/6 hours of OGSD/R with or without edaravone（0.1, 1, 10, 100 μM） treatment. We found that 100 μM of edaravone significantly suppressed astrocyte apoptosis and inhibited the release of reactive oxygen species. It also inhibited the activation of caspase-12 and caspase-3, and reduced the expression of homologous CCAAT/enhancer binding protein, phosphorylated（p）-PERK, p-eIF2α, and ATF4. These results point to a new use of an established drug in the prevention of OGSD/R-mediated spinal cord astrocyte apoptosis via the integrated stress response.

Surgical treatment of Pitt-Hopkins syndrome associated with strabismus and early-onset myopia:Two case reports

BACKGROUND Pitt-Hopkins syndrome(PTHS;MIM#610954)is a rare genetic neurological disorder.Myopia and strabismus have been reported in approximately 50%of PTHS patients.No studies have reported details about the required surgery for PTHS with strabismus and early-onset myopia.Here,we retrospectively reviewed the surgical management of two patients with PTHS combined with strabismus and/or early-onset myopia.CASE SUMMARY A 5-year-old girl presented with congenital esotropia and left eye myopia,and the second girl was a 5-year-old girl who presented with intermittent exotropia.Genetic testing performed on both patients showed a mutation in transcription factor 4,which is a diagnostic marker of PTHS.The first girl underwent bilateral medial rectus recession combined with posterior scleral reinforcement(PSR)in the left eye and the second patient underwent bilateral lateral rectus recession strabismus surgery.We made key innovations in surgical timing and strategy,and the results were satisfactory.The combination of strabismus and PSR surgery is an innovative strategy for patients with both strabismus and early-onset myopia.CONCLUSION Early treatment of strabismus and myopia positively influence motor development and should be included in rehabilitation programs for patients with PTHS.

Crohn’s disease-Defect in innate defence

Crohn’s disease may prinicipally involve the whole gastrointestinal tract. Most commonly, the inflammation occurs in the small intestine and/or in the colon with stable disease location over the years. The pathogenesis of both disease phenotypes is complex, the likely primary defect lies in the innate rather than adaptive immunity, particularly in the chemical antimicrobial barrier of the mucosa. Crohn’s ileitis is associated with a reduced expression of the Wnt signalling pathway transcription factor T-cell factor 4 (TCF4), which is regulating Paneth cell differentiation. As a result, the alpha-defensins and principal Paneth cell products HD5 and HD6 are deficiently expressed in ileal disease, independent of current inflammation. In contrast, Crohn’s colitis is typically associated with an impaired induction of the beta-defensins HBD2 and HBD3 caused by fewer gene copy numbers in the gene locus of the beta-defensins on chromosome 8. This ileal and colonic defect in innate defence mediated by a deficiency of the protective alpha- and beta- defensins may enable the luminal microbes to invade the mucosa and trigger the inflammation. A better understanding of the exact molecular mechanisms behind ileal and colonic Crohn’s disease may give rise to new therapeutic strategies based on a stimulation of the protective innate immune system.

Current understanding of ELF4 deficiency:a novel inborn error of immunity

Background ELF4 deficiency has been recently recognized as a novel disorder within the spectrum of inborn errors of immunity(IEIs),specifically categorized as a“disease of immune dysregulation.”Cases of this condition,reported by our team and others,are very limited worldwide.As such,our current knowledge of this new disease remains preliminary.This review aims to provide a brief overview of the clinical manifestations,pathogenesis,and treatment strategies for this novel IEI.Data sources A comprehensive review was conducted after an extensive literature search in the PubMed/Medline database and websites concerning transcriptional factor ELF4 and reports concerning patients with ELF4 deficiency.Our search strategy was“ELF4 OR ETS-related transcription factor Elf-4 OR EL4-like factor 4 OR myeloid Elf-1-like factor”as of the time of manuscript submission.Results The current signature manifestations of ELF4 deficiency disorder are recurrent and prolonged oral ulcer,abdominal pain,and diarrhea in pediatric males.In some cases,immunodeficiency and autoimmunity can also be prominent.Targeted Sanger sequencing or whole exome sequencing can be used to detect variation in ELF4 gene.Western blotting for ELF4 expression of the patient’s cells can confirm the pathogenic effect of the variant.To fully confirm the pathogenicity of the variant,further functional test is strongly advised.Glucocorticoid and biologics are the mainstream management of ELF4 deficiency disorder.Conclusions Pediatric males presenting with recurring ulcerations in digestive tract epithelium with or without recurrent fever should be suspected of DEX.When atypical presentations are prominent,variations in ELF4 gene should be carefully evaluated functionally due to the complex nature of ELF4 function.Experience of treating DEX includes use of glucocorticoid and biologics and more precise treatment needs more patients to identify and further mechanistic study.

UPF1 increases amino acid levels and promotes cell proliferation in lung adenocarcinoma via the eIF2α-ATF4 axis

Up-frameshift 1(UPF1),as the most critical factor in nonsense-mediated messenger RNA(mRNA)decay(NMD),regulates tumor-associated molecular pathways in many cancers.However,the role of UPF1 in lung adenocarcinoma(LUAD)amino acid metabolism remains largely unknown.In this study,we found that UPF1 was significantly correlated with a portion of amino acid metabolic pathways in LUAD by integrating bioinformatics and metabolomics.We further confirmed that UPF1 knockdown inhibited activating transcription factor 4(ATF4)and Ser51 phosphorylation of eukaryotic translation initiation factor 2α(eIF2α),the core proteins in amino acid metabolism reprogramming.In addition,UPF1 promotes cell proliferation by increasing the amino-acid levels of LUAD cells,which depends on the function of ATF4.Clinically,UPF1 mRNA expression is abnormal in LUAD tissues,and higher expression of UPF1 and ATF4 was significantly correlated with poor overall survival(OS)in LUAD patients.Our findings reveal that UPF1 is a potential regulator of tumor-associated amino acid metabolism and may be a therapeutic target for LUAD.

Leukemia Inhibitory Factor Enhanced the Developmental and Implantation Compatibility of Mouse Embryos in Co-culture with Human Endometrial Epithelial Cells

Objective:Among the variousin vitro embryo culture systems,co-culture has demonstrated remarkable effects in pre-implantation embryo development owing to the production of embryo-nourishing factors.Nevertheless,little is known about the secretion of these factors.Therefore,in this study,the effect of leukemia inhibitory factor(LIF),one of the most important nourishing factors in the early development of mouse embryos,in human endometrial epithelial cells(hEECs)was evaluated.Methods:Two-cell stage embryos were collected from the oviducts of hyper-stimulated and mated mice and cultivated in a co-culture with an hEEC monolayer with or without LIF.The quality and developmental and attachment potential rates of cultured embryos were evaluated by determining the levels of octamer-binding transcription factor 4(Oct4)and caudal type homeobox 2(Cdx2)transcripts.Results:LIF significantly increased the developmental rate(82.67%vs.61.04%,respectively)and attachment rate(64%vs.45.45%,respectively)of mouse embryos co-cultured with hEECs compared to those in untreated embryos.The expression levels ofOct4 andCdx2 in blastocysts cultured in the presence of LIF were higher than those in blastocysts cultured without LIF.Conclusions:Despite the secretion of LIF by hEECs during co-culture with embryos,the amount of this factor was insufficient,and its addition to the culture media could increase the developmental potential of embryos.

OCT4’s role and mechanism underlying oral squamous cell carcinoma

Oral squamous cell carcinoma(OSCC),a common malignancy of the head and neck,ranks sixth worldwide in terms of cancers with the most negative impact,owing to tumor relapse rates,cervical lymphnode metastasis,and the lack of an efficacious systemic therapy.Its prognosis is poor,and its mortality rate is high.Octamer-binding transcription factor 4(OCT4)is a member of the Pit-Oct-Unc(POU)family and is a key reprogramming factor that produces a marked effect in preserving the pluripotency and self-renewal state of embryonic stem cells(ESCs).According to recent studies,OCT4 participates in retaining the survival of OSCC cancer stem cells(CSCs),which has far-reaching implications for the occurrence,recurrence,metastasis,and prognosis of oral carcinogenesis.Therefore,we summarize the structure,subtypes,and function of OCT4 as well as its role in the occurrence,progression,and prognosis of OSCC.

Expression of interleukin-12 and its signaling molecules in peripheral blood mononuclear cells in systemic lupus erythematosus patients

Objective To determine the in vitro expression of interleukin-12 (IL-12) and its effect on signal transducers and activators of transcription (STAT) signaling molecules in peripheral blood mononuclear cells (PBMCs) in patients with systemic lupus erythematosus (SLE).Methods Peripheral blood mononuclear cells in 39 patients with definite systemic lupus erythematosus and 11 healthy volunteers were collected. Expression of IL-12 P40mRNA in PBMCs was determined with reverse transcription-polymerase chain reaction (RT-PCR). Quantity of IL-12 protein supernatant was measured by enzyme-linked immunosorbent assay (ELISA). The levels of phosphorylated STAT3 and STAT4 signaling molecules in PBMCs were detected by immunoblot. Results Levels of IL-12 protein and mRNA expression in patients with active or inactive SLE were significantly higher than those in controls. Phytohemagglutinin (PHA) may promote the expression of IL-12. IL-12 alone induced the phosphorylation of STAT3 and STAT4 in PBMCs from patients with SLE, especially in active SLE. However it had no obvious effect on normal PBMCs. Phosphorylated STAT3 and STAT4 might be observed in normal PBMCs treated with IL-12 plus PHA.Conclusion IL-12 is produced aberrantly in patients with SLE. IL-12 might exert its biological role in SLE via the aberrantly phosphorylated STAT3 and STAT4 signaling molecules.

Homeostatic responses to amino acid insufficiency

This article provides a brief overview describing how two key signaling pathways, namely the integrated stress response and the mammalian target of rapamycin complex 1, work together to facilitate cellular adaptation to dietary amino acid insufficiency. A deeper understanding of these mechanisms is leading to identification of novel targets which aid in disease treatments, improve stress recovery and increase health span through slowed aging and enhanced metabolic fitness.