Identification of the genes regulated by Wnt-4, a critical signal for commitment of the ovary

Calcium signaling induces partial EMT and renal fibrosis in a Wnt4mCherry knock-in mouse model

The renal tubular epithelial cells (TEC) have a strong capacity for repair after acute injury, but when this mechanism becomes uncontrollable, it leads to chronic kidney diseases (CKD). Indeed, in progress toward CKDs, the TECs may dedifferentiate, undergo epithelial-to-mesenchyme transition (EMT), and promote inflammation and fibrosis. Given the critical role of Wnt4 signaling in kidney ontogenesis, we addressed whether changes in this signaling are connected to renal inflammation and fibrosis by taking advantage of a knock-in Wnt4mCh/mCh mouse. While the Wnt4mCh/mCh embryos appeared normal, the corresponding mice, within one month, developed CKD-related phenotypes, such as pro-inflammatory responses including T-cell/macrophage influx, expression of fibrotic markers, and epithelial cell damage with a partial EMT. The Wnt signal transduction component β-catenin remained unchanged, while calcium signaling is induced in the injured TECs involving Nfat and Tfeb transcription factors. We propose that the Wnt4 signaling pathway is involved in repairing the renal injury, and when the signal is overdriven, CKD is established.

RUN(X) out of blood: emerging RUNX1 functions beyond hematopoiesis and links to Down syndrome

BACKGROUND

RUNX1 is a transcription factor and a master regulator for the specification of the hematopoietic lineage during embryogenesis and postnatal megakaryopoiesis. Mutations and rearrangements on RUNX1 are key drivers of hematological malignancies. In humans, this gene is localized to the 'Down syndrome critical region' of chromosome 21, triplication of which is necessary and sufficient for most phenotypes that characterize Trisomy 21.

MAIN BODY

Individuals with Down syndrome show a higher predisposition to leukemias. Hence, RUNX1 overexpression was initially proposed as a critical player on Down syndrome-associated leukemogenesis. Less is known about the functions of RUNX1 in other tissues and organs, although growing reports show important implications in development or homeostasis of neural tissues, muscle, heart, bone, ovary, or the endothelium, among others. Even less is understood about the consequences on these tissues of RUNX1 gene dosage alterations in the context of Down syndrome. In this review, we summarize the current knowledge on RUNX1 activities outside blood/leukemia, while suggesting for the first time their potential relation to specific Trisomy 21 co-occurring conditions.

CONCLUSION

Our concise review on the emerging RUNX1 roles in different tissues outside the hematopoietic context provides a number of well-funded hypotheses that will open new research avenues toward a better understanding of RUNX1-mediated transcription in health and disease, contributing to novel potential diagnostic and therapeutic strategies for Down syndrome-associated conditions.

CgWnt-1 regulates haemocyte proliferation during immune response of oyster Crassostrea gigas

Recent findings regarding the immunomodulatory role of Wnt signaling suggest that it is significant in regulating the differentiation and proliferation of immune cells. In the present study, a Wnt-1 homolog (designated as CgWnt-1) with a conserved WNT1 domain was identified from oyster Crassostrea gigas. The transcripts of CgWnt-1 were barely expressed in egg to gastrula stage during early embryogenesis, and up-regulated significantly in the trochophore to juvenile stage. The mRNA transcripts of CgWnt-1 were detected in different tissues of adult oyster, with an extremely high expression level in the mantle, which was 77.38-fold (p < 0.05) of that in labial palp. After Vibrio splendidus stimulation, the mRNA expression levels of CgWnt-1 and Cgβ-catenin in haemocytes up-regulated significantly at 3, 12, 24, and 48 h (p < 0.05). After injection of recombinant protein (rCgWnt-1) into oyster in vivo, the expressions of Cgβ-catenin, cell proliferation related genes CgRunx-1 and CgCDK-2 in haemocytes significantly up-regulated, which were 4.86-fold (p < 0.05), 9.33-fold (p < 0.05), 6.09-fold (p < 0.05) of those in rTrx group, respectively. The percentage of EDU⁺ cells in haemocytes also significantly increased (2.88-fold of that in control group, p < 0.05) at 12 h after rCgWnt-1 treatment. When the Wnt signal inhibitor C59 was injected simultaneously with rCgWnt-1, the expressions of Cgβ-catenin, CgRunx-1, and CgCDK-2 were significantly reduced, which were 0.32-fold (p < 0.05), 0.16-fold (p < 0.05), and 0.25-fold (p < 0.05) of that in rCgWnt-1 group, respectively, and the percentage of EDU⁺ cells in haemocytes was also significantly inhibited (0.15-fold compared with that in rCgWnt-1 group, p < 0.05). These results suggested that the conserved CgWnt-1 could modulate haemocytes proliferation via regulating cell cycle related genes and involved in the immune response of oysters.

The transcription factor RUNX1 affects the maturation of porcine oocytes via the BMP15/TGF-β signaling pathway

Bone morphogenetic protein 15 (BMP15) is specifically expressed in oocytes in pigs at all stages from early stages to ovulation and has an important role in oocyte maturation. However, there are few reports on the molecular mechanisms by which BMP15 affects oocyte maturation. In this study, we identified the core promoter region of BMP15 using a dual luciferase activity assay and successfully predicted the DNA binding motif of the transcription factor RUNX1. The effect of BMP15 and RUNX1 on oocyte maturation was examined using the first polar body extrusion rate, a reactive oxygen species (ROS) assay and total glutathione (GSH) content at three time points of 12, 24 and 48 h of in vitro culture of porcine isolated oocytes. Subsequently, the effect of the transcription factor RUNX1 on the TGF-β signaling pathway (BMPR1B and ALK5) was further verified using RT-qPCR and Western blotting. We found that the overexpression of BMP15 significantly increased the first polar body extrusion rate (P < 0.01) and total glutathione content of oocytes cultured in vitro for 24 h and decreased reactive oxygen levels (P < 0.01), whereas interference with BMP15 decreased the first polar body extrusion rate (P < 0.01), increased reactive oxygen levels in oocytes cultured in vitro for 24 h (P < 0.01), and decreased glutathione content (P < 0.01). The dual luciferase activity assay and online software prediction showed that RUNX1 is a potential transcription factor binding to the core promoter region (-1203/-1423 bp) of BMP15. Overexpression of RUNX1 significantly increased the expression of BMP15 and oocyte maturation rate, while inhibition of RUNX1 decreased the expression of BMP15 and the oocyte maturation rate. Moreover, the expression of BMPR1B and ALK5 in the TGF-β signaling pathway increased significantly after overexpression of RUNX1, whereas their expression decreased after inhibition of RUNX1. Overall, our results suggest that the transcription factor RUNX1 positively regulates the expression of BMP15 and influences oocyte maturation through the TGF-β signaling pathway. This study provides a theoretical basis for further complementing the BMP15/TGF-β signaling pathway to regulate mammalian oocyte maturation.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Carrying MicroRNA-29a Improves Ovarian Function of Mice with Primary Ovarian Insufficiency by Targeting HMG-Box Transcription Factor/Wnt/β-Catenin Signaling

Background

Primary ovarian insufficiency (POI) is a female disease characterized by ovarian function loss under 40 years old. Transplantation of exosomes is an encouraging regenerative medicine method that has the potential for restoring ovarian functions post-POI with high efficiency. Therefore, we investigate the therapeutic efficacy and potential mechanisms of human umbilical cord mesenchymal stem cell- (UCMSC-) derived exosomes on ovarian dysfunction post-POI.

Methods

The model of POI was established by intraperitoneal injection with 5 mg/kg cisplatin. The mouse ovarian function was detected by measuring the levels of anti-Mullerian hormone, follicle-stimulating hormone, and estradiol and detecting the morphological changes. For in vitro experiments, the characterization and identification of UCMSCs and UCMSC-derived exosomes were done by observation of morphologies and flow cytometry. To exclude the interference effect of nonspecific precipitation substances, UCMSCs were treated with RNase A or RNase A in combination with Triton X-100. Granulosa cell (GC) identification was performed using immunofluorescence. GC proliferation and viability were assessed using 5-ethynyl-2′-deoxyuridine (EdU) assays and Cell Counting Kit-8 (CCK-8), and GC apoptosis was calculated by flow cytometry. Gene expression and protein levels were evaluated using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting. The binding relationship between miR-29a and HMG-box transcription factor (HBP1) was verified by luciferase reporter assays.

Results

In vitro, the human UCMSC-derived exosomes carrying miR-29a upregulation promoted the proliferation of GCs and suppressed their apoptosis. In vivo, miR-29a upregulation reserved the mature follicles and restored the ovarian functions. miR-29a targeted HBP1 and negatively regulated its expression. HBP1 upregulation rescued the miR-29a upregulation-induced inhibition in GC apoptosis and inactivated the Wnt/β-catenin pathway.

Conclusion

The exosomal miR-29a derived from human UCMSCs improves the ovarian function by targeting HBP1 and activating the Wnt/β-catenin pathway.

Identification of sex determination locus in sea cucumber Apostichopus japonicus using genome-wide association study

Background

Sex determination mechanisms are complicated and diverse across taxonomic categories. Sea cucumber Apostichopus japonicus is a benthic echinoderm, which is the closest group of invertebrates to chordate, and important economic and ecologically aquaculture species in China. A. japonicus is dioecious, and no phenotypic differences between males and females can be detected before sexual maturation. Identification of sex determination locus will broaden knowledge about sex-determination mechanism in echinoderms, which allows for the identification of sex-linked markers and increases the efficiency of sea cucumber breeding industry.

Results

Here, we integrated assembly of a novel chromosome-level genome and resequencing of female and male populations to investigate the sex determination mechanisms of A. japonicus. We built a chromosome-level genome assembly AJH1.0 using Hi-C technology. The assembly AJH1.0 consists of 23 chromosomes ranging from 22.4 to 60.4 Mb. To identify the sex-determination locus of A. japonicus, we conducted genome-wide association study (GWAS) and analyses of distribution characteristics of sex-specific SNPs and fixation index F_ST. The GWAS analysis showed that multiple sex-associated loci were located on several chromosomes, including chromosome 4 (24.8%), followed by chromosome 9 (10.7%), chromosome 17 (10.4%), and chromosome 18 (14.1%). Furthermore, analyzing the homozygous and heterozygous genotypes of plenty of sex-specific SNPs in females and males confirmed that A. japonicus might have a XX/XY sex determination system. As a physical region of 10 Mb on chromosome 4 included the highest number of sex-specific SNPs and higher F_ST values, this region was considered as the candidate sex determination region (SDR) in A. japonicus.

Conclusions

In the present study, we integrated genome-wide association study and analyses of sex-specific variations to investigate sex determination mechanisms. This will bring novel insights into gene regulation during primitive gonadogenesis and differentiation and identification of master sex determination gene in sea cucumber. In the sea cucumber industry, investigation of molecular mechanisms of sex determination will be helpful for artificial fertilization and precise breeding.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08632-3.

Lhx2 in germ cells suppresses endothelial cell migration in the developing ovary

LIM-homeobox genes play multiple roles in developmental processes, but their roles in gonad development are not completely understood. Herein, we report that Lhx2, Ils2, Lmx1a, and Lmx1b are expressed in a sexually dimorphic manner in mouse, rat, and human gonads during sex determination. Amongst these, Lhx2 has female biased expression in the developing gonads of species with environmental and genetic modes of sex determination. Single-cell RNAseq analysis revealed that Lhx2 is exclusively expressed in the germ cells of the developing mouse ovaries. To elucidate the roles of Lhx2 in the germ cells, we analyzed the phenotypes of Lhx2 knockout XX gonads. While the gonads developed appropriately in Lhx2 knockout mice and the somatic cells were correctly specified in the developing ovaries, transcriptome analysis revealed enrichment of genes in the angiogenesis pathway. There was an elevated expression of several pro-angiogenic factors in the Lhx2 knockout ovaries. The elevated expression of pro-angiogenic factors was associated with an increase in numbers of endothelial cells in the Lhx2-/- ovaries at E13.5. Gonad recombination assays revealed that the increased numbers of endothelial cells in the XX gonads in absence of Lhx2 was due to ectopic migration of endothelial cells in a cell non-autonomous manner. We also found that, there was increased expression of several endothelial cell-enriched male-biased genes in Lhx2 knockout ovaries. Also, in absence of Lhx2, the migrated endothelial cells formed an angiogenic network similar to that of the wild type testis, although the coelomic blood vessel did not form. Together, our results suggest that Lhx2 in the germ cells is required to suppress vascularization in the developing ovary. These results suggest a need to explore the roles of germ cells in the control of vascularization in developing gonads. Preprint version of the article is available on BioRxiv at https://doi.org/10.1101/2022.03.07.483280.

RUNX1 can mediate the glucose and O-GlcNAc-driven proliferation and migration of human retinal microvascular endothelial cells

INTRODUCTION

This study aims to determine whether high glucose condition and dynamic O-linked N-acetylglucosamine (O-GlcNAc) modification can promote the proliferation and migration of human retinal microvascular endothelial cells (HRMECs) and whether Runt-related transcription factor 1 (RUNX1) could mediate the glucose and O-GlcNAc-driven proliferation and migration of HRMECs.

RESEARCH DESIGN AND METHODS

Western blot analysis was used to detect the O-GlcNAc modification level and RUNX1 level in cells and retina tissues, cell growth was studied by cell counting kit-8 assay, cell proliferation was detected by immunofluorescence staining. Then, cell migration and tube formation were investigated by scratch-wound assay, Transwell assay, and tube-forming assay. The changes of retinal structure were detected by H&E staining. The O-GlcNAc modification of RUNX1 was detected by immunoprecipitation.

RESULTS

High glucose increases pan-cellular O-GlcNAc modification and the proliferation and migration of HRMECs. Hence, O-GlcNAc modification is critical for the proliferation and migration of HRMECs. RUNX1 mediates the glucose and O-GlcNAc-driven proliferation and migration in HRMECs. RUNX1 can be modified by O-GlcNAc, and that the modification is enhanced in a high glucose environment.

CONCLUSIONS

The present study reveals that high glucose condition directly affects retinal endothelial cells (EC) function, and O-GlcNAc modification is critical for the proliferation and migration of HRMECs, RUNX1 may take part in this mechanism, and maybe the function of RUNX1 is related to its O-GlcNAc modification level, which provides a new perspective for studying the mechanism of RUNX1 in diabetic retinopathy.

Evolutionary Turnover in Wnt Gene Expression but Conservation of Wnt Signaling during Ovary Determination in a TSD Reptile

Temperature-dependent sex determination (TSD) is a well-known characteristic of many reptilian species. However, the molecular processes linking ambient temperature to determination of gonad fate remain hazy. Here, we test the hypothesis that Wnt expression and signaling differ between female- and male-producing temperatures in the snapping turtle Chelydra serpentina. Canonical Wnt signaling involves secretion of glycoproteins called WNTs, which bind to and activate membrane bound receptors that trigger β-catenin stabilization and translocation to the nucleus where β-catenin interacts with TCF/LEF transcription factors to regulate expression of Wnt targets. Non-canonical Wnt signaling occurs via 2 pathways that are independent of β-catenin: one involves intracellular calcium release (the Wnt/Ca2+ pathway), while the other involves activation of RAC1, JNK, and RHOA (the Wnt/planar cell polarity pathway). We screened 20 Wnt genes for differential expression between female- and male-producing temperatures during sex determination in the snapping turtle. Exposure of embryos to the female-producing temperature decreased expression of 7 Wnt genes but increased expression of 2 Wnt genes and Rspo1 relative to embryos at the male-producing temperature. Temperature also regulated expression of putative Wnt target genes in vivo and a canonical Wnt reporter (6x TCF/LEF sites drive H2B-GFP expression) in embryonic gonadal cells in vitro. Results indicate that Wnt signaling was higher at the female- than at the male-producing temperature. Evolutionary analyses of all 20 Wnt genes revealed that thermosensitive Wnts, as opposed to insensitive Wnts, were less likely to show evidence of positive selection and experienced stronger purifying selection within TSD species.

Genome-wide profile in DNA methylation in goat ovaries of two different litter size populations

Although some studies have investigated the DNA methylation modification in goat ovaries, it is not understood DNA methylation related to goat litter size. This investigation was designed to explore the DNA methylation status in the ovaries of high litter size and low litter size groups using whole-genome bisulfite sequencing (WGBS). We found that there was global difference on DNA methylation in high litter size and low litter size goat ovaries. Many differentially methylated region-related genes (DMGs) were found in the ovaries of these two different goat populations. Moreover, enrichment analysis discovered that many DMGs were involved in gamete development, reproductive system development, wingless-type MMTV integration site family (WNT) signalling pathways and mitogen-activated protein kinase 1 (MAPK) signalling pathways. The data indicated that DNA methylation in goat ovaries may play important roles in the folliculogenesis, the oocyte ovulation rate and finally the litter size. This study provides a comprehensive analysis of genome-wide DNA methylation patterns in ovaries of high and low litter size goat which helps the understanding of ovarian DNA methylation in relation to goat fertility capability.

WNT4 Balances Development vs Disease in Gynecologic Tissues and Women's Health

The WNT family of proteins is crucial in numerous developmental pathways and tissue homeostasis. WNT4, in particular, is uniquely implicated in the development of the female phenotype in the fetus, and in the maintenance of müllerian and reproductive tissues. WNT4 dysfunction or dysregulation can drive sex-reversal syndromes, highlighting the key role of WNT4 in sex determination. WNT4 is also critical in gynecologic pathologies later in life, including several cancers, uterine fibroids, endometriosis, and infertility. The role of WNT4 in normal decidualization, implantation, and gestation is being increasingly appreciated, while aberrant activation of WNT4 signaling is being linked both to gynecologic and breast cancers. Notably, single-nucleotide polymorphisms (SNPs) at the WNT4 gene locus are strongly associated with these pathologies and may functionally link estrogen and estrogen receptor signaling to upregulation and activation of WNT4 signaling. Importantly, in each of these developmental and disease states, WNT4 gene expression and downstream WNT4 signaling are regulated and executed by myriad tissue-specific pathways. Here, we review the roles of WNT4 in women's health with a focus on sex development, and gynecologic and breast pathologies, and our understanding of how WNT4 signaling is controlled in these contexts. Defining WNT4 functions provides a unique opportunity to link sex-specific signaling pathways to women's health and disease.

SPATS1 (spermatogenesis-associated, serine-rich 1) is not essential for spermatogenesis and fertility in mouse

SPATS1 (spermatogenesis-associated, serine-rich 1) is an evolutionarily conserved, testis-specific protein that is differentially expressed during rat male meiotic prophase. Some reports have suggested a link between SPATS1 underexpression/mutation and human pathologies such as male infertility and testicular cancer. Given the absence of functional studies, we generated a Spats1 loss-of-function mouse model using CRISPR/Cas9 technology. The phenotypic analysis showed no overt phenotype in Spats1^-/- mice, with both males and females being fertile. Flow cytometry and histological analyses did not show differences in the testicular content and histology between WT and knockout mice. Moreover, no significant differences in sperm concentration, motility, and morphology, were observed between WT and KO mice. These results were obtained both for young adults and for aged animals. Besides, although an involvement of SPATS1 in the Wnt signaling pathway has been suggested, we did not detect changes in the expression levels of typical Wnt pathway-target genes in mutant individuals. Thus, albeit Spats1 alteration might be a risk factor for male testicular health, we hereby show that this gene is not individually essential for male fertility and spermatogenesis in mouse.

Protective Effects of Puerarin on Premature Ovarian Failure via Regulation of Wnt/β-catenin Signaling Pathway and Oxidative Stress

This study was designed to investigate the protective effects of puerarin (PUE), which work via the Wnt/β-catenin signaling pathway, and oxidative stress in the premature ovarian failure (POF) model. Two-month-old female mice were randomly divided into four groups. One group was used as the control, and the other three groups were injected with cyclophosphamide and busulfan to create POF models. Two POF treatment groups were gavaged with 100 or 200 mg/kg PUE for 28 days. Next, the ovaries were fixed, and the numbers of different stage follicles were measured, and the ovarian surface epithelium (OSE) was collected. Oct4 and Mvh expression, Wnt/β-catenin signaling pathway activity, the oxidative stress factors SOD2 and Nrf2, and the apoptosis-related proteins Bcl-2 and Bax were detected by IHC, RT-QPCR, and western blotting. We found that the number of follicles, Oct4 and Mvh expression, and Wnt/β-catenin-signaling activity were reduced in the POF groups (p < 0.05 or p < 0.001). After PUE treatment, the follicle number and the primordial follicle ratio increased (p < 0.01), while the atresia ratio decreased (p < 0.01). In addition, the expression levels of Oct4, Mvh, Wnt1, β-catenin, cyclin D1, SOD2, and Nrf2 showed obvious recovery compared with levels in the POF group (p < 0.01, p < 0.05, or p < 0.001). The Bcl-2/Bax ratio in the POF model had reduced by about 60% compared with the control group (p < 0.001) and improved by about 50% after PUE treatment (p < 0.001). In conclusion, PUE may improve the survival of female reproductive stem cells (FGSCs) and play a protective role against POF via a mechanism involving the Wnt/β-catenin signaling pathway, as well as relieving oxidative stress. Further investigations should focus on the culture of oocytes and FGSCs in vitro in a PUE environment with inhibitors or agonists of the Wnt signaling pathway.

Canonical Wnt/β-catenin activity and differential epigenetic marks direct sexually dimorphic regulation of Irx3 and Irx5 in developing mouse gonads

Members of the Iroquois B (IrxB) homeodomain cluster genes, specifically Irx3 and Irx5, are crucial for heart, limb and bone development. Recently, we reported their importance for oocyte and follicle survival within the developing ovary. Irx3 and Irx5 expression begins after sex determination in the ovary but remains absent in the fetal testis. Mutually antagonistic molecular signals ensure ovary versus testis differentiation with canonical Wnt/β-catenin signals paramount for promoting the ovary pathway. Notably, few direct downstream targets have been identified. We report that Wnt/β-catenin signaling directly stimulates Irx3 and Irx5 transcription in the developing ovary. Using in silico analysis of ATAC- and ChIP-Seq databases in conjunction with mouse gonad explant transfection assays, we identified TCF/LEF-binding sequences within two distal enhancers of the IrxB locus that promote β-catenin-responsive ovary expression. Meanwhile, Irx3 and Irx5 transcription is suppressed within the developing testis by the presence of H3K27me3 on these same sites. Thus, we resolved sexually dimorphic regulation of Irx3 and Irx5 via epigenetic and β-catenin transcriptional control where their ovarian presence promotes oocyte and follicle survival vital for future ovarian health.

Absence of a Faster-X Effect in Beetles (Tribolium, Coleoptera)

The faster-X effect, namely the rapid evolution of protein-coding genes on the X chromosome, has been widely reported in metazoans. However, the prevalence of this phenomenon across diverse systems and its potential causes remain largely unresolved. Analysis of sex-biased genes may elucidate its possible mechanisms: for example, in systems with X/Y males a more pronounced faster-X effect in male-biased genes than in female-biased or unbiased genes may suggest fixation of recessive beneficial mutations rather than genetic drift. Further, theory predicts that the faster-X effect should be promoted by X chromosome dosage compensation. Here, we asked whether we could detect a faster-X effect in genes of the beetle Tribolium castaneum (and T. freemani orthologs), which has X/Y sex-determination and heterogametic males. Our comparison of protein sequence divergence (dN/dS) on the X chromosome vs. autosomes indicated a rarely observed absence of a faster-X effect in this organism. Further, analyses of sex-biased gene expression revealed that the X chromosome was particularly highly enriched for ovary-biased genes, which evolved slowly. In addition, an evaluation of male X chromosome dosage compensation in the gonads and in non-gonadal somatic tissues indicated a striking lack of compensation in the testis. This under-expression in testis may limit fixation of recessive beneficial X-linked mutations in genes transcribed in these male sex organs. Taken together, these beetles provide an example of the absence of a faster-X effect on protein evolution in a metazoan, that may result from two plausible factors, strong constraint on abundant X-linked ovary-biased genes and a lack of gonadal dosage compensation.

Complex Interplay between the RUNX Transcription Factors and Wnt/β-Catenin Pathway in Cancer: A Tango in the Night

Cells are designed to be sensitive to a myriad of external cues so they can fulfil their individual destiny as part of the greater whole. A number of well-characterised signalling pathways dictate the cell's response to the external environment and incoming messages. In healthy, well-ordered homeostatic systems these signals are tightly controlled and kept in balance. However, given their powerful control over cell fate, these pathways, and the transcriptional machinery they orchestrate, are frequently hijacked during the development of neoplastic disease. A prime example is the Wnt signalling pathway that can be modulated by a variety of ligands and inhibitors, ultimately exerting its effects through the β-catenin transcription factor and its downstream target genes. Here we focus on the interplay between the three-member family of RUNX transcription factors with the Wnt pathway and how together they can influence cell behaviour and contribute to cancer development. In a recurring theme with other signalling systems, the RUNX genes and the Wnt pathway appear to operate within a series of feedback loops. RUNX genes are capable of directly and indirectly regulating different elements of the Wnt pathway to either strengthen or inhibit the signal. Equally, β-catenin and its transcriptional co-factors can control RUNX gene expression and together they can collaborate to regulate a large number of third party co-target genes.

RUNX1 promotes tumour metastasis by activating the Wnt/β-catenin signalling pathway and EMT in colorectal cancer

Background

Runt-related transcription factor 1 (RUNX1) plays the roles of an oncogene and an anti-oncogene in epithelial tumours, and abnormally elevated RUNX1 has been suggested to contribute to the carcinogenesis of colorectal cancer (CRC). However, the mechanism remains unclear.

Methods

The expression of RUNX1 in CRC and normal tissues was detected by real-time quantitative PCR and Western blotting. The effect of RUNX1 on CRC migration and invasion was conducted by functional experiments in vitro and in vivo. Chromatin Immunoprecipitation assay verified the direct regulation of RUNX1 on the promoter of the KIT, which leads to the activation of Wnt/β-catenin signaling.

Results

RUNX1 expression is upregulated in CRC tissues. Upregulated RUNX1 promotes cell metastasis and epithelial to mesenchymal transition (EMT) of CRC both in vitro and in vivo. Furthermore, RUNX1 can activate Wnt/β-catenin signalling in CRC cells by directly interacting with β-catenin and targeting the promoter and enhancer regions of KIT to promote KIT transcription. These observations demonstrate that RUNX1 upregulation is a common event in CRC specimens and is closely correlated with cancer metastasis and that RUNX1 promotes EMT of CRC cells by activating Wnt/β-catenin signalling. Moreover, RUNX1 is regulated by Wnt/β-catenin.

Conclusion

Our findings first demonstrate that RUNX1 promotes CRC metastasis by activating the Wnt/β-catenin signalling pathway and EMT.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1330-9) contains supplementary material, which is available to authorized users.

Notum produced by Paneth cells attenuates regeneration of aged intestinal epithelium

A decline in stem cell function impairs tissue regeneration during ageing, but the role of the stem-cell-supporting niche in ageing is not well understood. The small intestine is maintained by actively cycling intestinal stem cells that are regulated by the Paneth cell niche^1,2. Here we show that the regenerative potential of human and mouse intestinal epithelium diminishes with age owing to defects in both stem cells and their niche. The functional decline was caused by a decrease in stemness-maintaining Wnt signalling due to production of Notum, an extracellular Wnt inhibitor, in aged Paneth cells. Mechanistically, high activity of mammalian target of rapamycin complex 1 (mTORC1) in aged Paneth cells inhibits activity of peroxisome proliferator activated receptor α (PPAR-α)³, and lowered PPAR-α activity increased Notum expression. Genetic targeting of Notum or Wnt supplementation restored function of aged intestinal organoids. Moreover, pharmacological inhibition of Notum in mice enhanced the regenerative capacity of aged stem cells and promoted recovery from chemotherapy-induced damage. Our results reveal a role of the stem cell niche in ageing and demonstrate that targeting of Notum can promote regeneration of aged tissues.

Epigenetic Repression of Androgen Receptor Transcription in Mutation-Negative Androgen Insensitivity Syndrome (AIS Type II)

CONTEXT

Inactivating mutations within the AR gene are present in only ~40% of individuals with clinically and hormonally diagnosed androgen insensitivity syndrome (AIS). Previous studies revealed the existence of an AR gene mutation-negative group of patients with AIS who have compromised androgen receptor (AR) function (AIS type II).

OBJECTIVE

To investigate whether AIS type II can be due to epigenetic repression of AR transcription.

DESIGN

Quantification of AR mRNA and AR proximal promoter CpG methylation levels in genital skin-derived fibroblasts (GFs) derived from patients with AIS type II and control individuals.

SETTING

University hospital endocrine research laboratory.

PATIENTS

GFs from control individuals (n = 11) and patients with AIS type II (n = 14).

MAIN OUTCOME MEASURE(S)

Measurement of AR mRNA and AR promoter CpG methylation as well as activity of AR proximal promoter in vitro.

RESULTS

Fifty-seven percent of individuals with AIS type II (n = 8) showed a reduced AR mRNA expression in their GFs. A significant inverse correlation was shown between AR mRNA abundance and methylation at two consecutive CpGs within the proximal AR promoter. Methylation of a 158-bp-long region containing these CpGs was sufficient to severely reduce reporter gene expression. This region was bound by the runt related transcription factor 1 (RUNX1). Ectopic expression of RUNX1 in HEK293T cells was able to inhibit reporter gene expression through this region.

CONCLUSIONS

Aberrant CpGs methylation within the proximal AR promoter plays an important role in the control of AR gene expression and may result in AIS type II. We suggest that transcriptional modifiers, such as RUNX1, could play roles therein offering new perspectives for understanding androgen-mediated endocrine diseases.

Transcriptome analysis of the adult human Klinefelter testis and cellularity-matched controls reveals disturbed differentiation of Sertoli- and Leydig cells

The most common human sex chromosomal disorder is Klinefelter syndrome (KS; 47,XXY). Adult patients with KS display a diverse phenotype but are nearly always infertile, due to testicular degeneration at puberty. To identify mechanisms causing the selective destruction of the seminiferous epithelium, we performed RNA-sequencing of 24 fixed paraffin-embedded testicular tissue samples. Analysis of informative transcriptomes revealed 235 differentially expressed transcripts (DETs) in the adult KS testis showing enrichment of long non-coding RNAs, but surprisingly not of X-chromosomal transcripts. Comparison to 46,XY samples with complete spermatogenesis and Sertoli cell-only-syndrome allowed prediction of the cellular origin of 71 of the DETs. DACH2 and FAM9A were validated by immunohistochemistry and found to mark apparently undifferentiated somatic cell populations in the KS testes. Moreover, transcriptomes from fetal, pre-pubertal, and adult KS testes showed a limited overlap, indicating that different mechanisms are likely to operate at each developmental stage. Based on our data, we propose that testicular degeneration in men with KS is a consequence of germ cells loss initiated during early development in combination with disturbed maturation of Sertoli- and Leydig cells.

Transcriptome analysis of sex-related genes in the blood clam Tegillarca granosa

BACKGROUND

Blood clams (Tegillarca granosa) are one of the most commercial shellfish in China and South Asia with wide distribution in Indo-Pacific tropical to temperate estuaries. However, recent data indicate a decline in the germplasm of this species. Furthermore, the molecular mechanisms underpinning reproductive regulation remain unclear and information regarding genetic diversity is limited. Understanding the reproductive biology of shellfish is important in interpreting their embryology development, reproduction and population structure. Transcriptome sequencing (RNA-seq) rapidly obtains genetic sequence information from almost all transcripts of a particular tissue and currently represents the most prevalent and effective method for constructing genetic expression profiles.

RESULTS

Non-reference RNA-seq, an Illumina HiSeq2500 Solexa system, and de novo assembly were used to construct a gonadal expression profile of the blood clam. A total of 63.75 Gb of clean data, with at least 89.46% of Quality30 (Q30), were generated which was then combined into 214,440 transcripts and 125,673 unigenes with a mean length of 1,122.63 and 781.30 base pairs (bp). In total, 27,325 genes were annotated by comparison with public databases. Of these, 2,140 and 2,070 differentially expressed genes (DEGs) were obtained (T05 T08 vs T01 T02 T04, T06 T07 vs T01 T02 T04; in which T01-T04 and T05-T08 represent biological replicates of individual female and male clams, respectively) and classified into two groups according to the evaluation of biological replicates. Then 35 DEGs and 5 sex-related unigenes, in other similar species, were investigated using qRT-PCR, the results of which were confirmed to data arising from RNA-seq. Among the DEGs, sex-related genes were identified, including forkhead box L2 (Foxl2), sex determining region Y-box (Sox), beta-catenin (β-catenin), chromobox homolog (CBX) and Sex-lethal (Sxl). In addition, 6,283 simple sequence repeats (SSRs) and 614,710 single nucleotide polymorphisms (SNPs) were identified from the RNA-seq results.

CONCLUSIONS

This study provided the first complete gonadal transcriptome data for the blood clam and allowed us to search many aspects of gene sequence information, not limited to gender. This data will improve our understanding of the transcriptomics and reproductive biology of the blood clam. Furthermore, molecular markers such as SSRs and SNPs will be useful in the analysis of genetic evolution, bulked segregant analysis (BSA) and genome-wide association studies (GWAS). Our transcriptome data will therefore provide important genetic information for the breeding and conservation of germplasm.

ATRA Signaling Regulates the Expression of COL9A1 through BMP2-WNT4-RUNX1 Pathway in Antler Chondrocytes

Although all-trans retinoic acid (ATRA) is involved in the regulation of cartilage growth and development, its regulatory mechanisms remain unknown. Here, we showed that ATRA could induce the expression of COL9A1 in antler chondrocytes. Silencing of cellular retinoic acid binding protein 2 (CRABP2) could impede the ATRA-induced upregulation of COL9A1, whereas overexpression of CRABP2 presented the opposite effect. RARα agonist Am80 induced the expression of COL9A1, whereas treatment with RARα antagonist Ro 41-5253 or RXRα small-interfering RNA (siRNA) caused an obvious blockage of ATRA on COL9A1. In antler chondrocytes, CYP26A1 and CYP26B1 weakened the sensitivity of ATRA to COL9A1. Simultaneously, Bone morphogenetic protein 2 (BMP2) and WNT4 mediated the regulation of ATRA on COL9A1 expression. Knockdown of WNT4 could abrogate the inhibitory effect of BMP2 overexpression on COL9A1. Conversely, constitutive expression of WNT4 reversed the upregulation of COL9A1 elicited by BMP2 siRNA. Together these data indicated that WNT4 might act downstream of BMP2 to mediate the effect of ATRA on COL9A1 expression. Further analysis evidenced that attenuation of runt-related transcription factor 1 (RUNX1) could prevent the stimulation of ATRA on COL9A1 expression, while exogenous rRUNX1 further enhanced this effectiveness. Moreover, RUNX1 might serve as an intermediate to mediate the regulation of BMP2 and WNT4 on COL9A1 expression. Collectively, ATRA signaling might regulate the expression of COL9A1 through BMP2-WNT4-RUNX1 pathway.

The enigmatic role of RUNX1 in female-related cancers - current knowledge & future perspectives

Historically associated with the aetiology of human leukaemia, the runt-related transcription factor 1 (RUNX1) gene has in recent years reared its head in an assortment of epithelial cancers. This review discusses the state-of-the-art knowledge of the enigmatic role played by RUNX1 in female-related cancers of the breast, the uterus and the ovary. The weight of evidence accumulated so far is indicative of a very context-dependent role, as either an oncogene or a tumour suppressor. This is corroborated by high-throughput sequencing endeavours which report different genetic alterations affecting the gene, including amplification, deep deletion and mutations. Herein, we attempt to dissect that contextual role by firstly giving an overview of what is currently known about RUNX1 function in these specific tumour types, and secondly by delving into connections between this transcription factor and the physiology of these female tissues. In doing so, RUNX1 emerges not only as a gene involved in female sex development but also as a crucial mediator of female hormone signalling. In view of RUNX1 now being listed as a driver gene, we believe that greater knowledge of the mechanisms underlying its functional dualism in epithelial cancers is worthy of further investigation.

RUNX in Invertebrates

Runx genes have been identified in all metazoans and considerable conservation of function observed across a wide range of phyla. Thus, insight gained from studying simple model organisms is invaluable in understanding RUNX biology in higher animals. Consequently, this chapter will focus on the Runx genes in the diploblasts, which includes sea anemones and sponges, as well as the lower triploblasts, including the sea urchin, nematode, planaria and insect. Due to the high degree of functional redundancy amongst vertebrate Runx genes, simpler model organisms with a solo Runx gene, like C. elegans, are invaluable systems in which to probe the molecular basis of RUNX function within a whole organism. Additionally, comparative analyses of Runx sequence and function allows for the development of novel evolutionary insights. Strikingly, recent data has emerged that reveals the presence of a Runx gene in a protist, demonstrating even more widespread occurrence of Runx genes than was previously thought. This review will summarize recent progress in using invertebrate organisms to investigate RUNX function during development and regeneration, highlighting emerging unifying themes.

WNT4 mediates estrogen receptor signaling and endocrine resistance in invasive lobular carcinoma cell lines

BACKGROUND

Invasive lobular carcinoma (ILC) of the breast typically presents with clinical biomarkers consistent with a favorable response to endocrine therapies, and over 90 % of ILC cases express the estrogen receptor (ER). However, a subset of ILC cases may be resistant to endocrine therapies, suggesting that ER biology is unique in ILC. Using ILC cell lines, we previously demonstrated that ER regulates a distinct gene expression program in ILC cells, and we hypothesized that these ER-driven pathways modulate the endocrine response in ILC. One potential novel pathway is via the Wnt ligand WNT4, a critical signaling molecule in mammary gland development regulated by the progesterone receptor.

METHODS

The ILC cell lines MDA-MB-134-VI, SUM44PE, and BCK4 were used to assess WNT4 gene expression and regulation, as well as the role of WNT4 in estrogen-regulated proliferation. To assess these mechanisms in the context of endocrine resistance, we developed novel ILC endocrine-resistant long-term estrogen-deprived (ILC-LTED) models. ILC and ILC-LTED cell lines were used to identify upstream regulators and downstream signaling effectors of WNT4 signaling.

RESULTS

ILC cells co-opted WNT4 signaling by placing it under direct ER control. We observed that ER regulation of WNT4 correlated with use of an ER binding site at the WNT4 locus, specifically in ILC cells. Further, WNT4 was required for endocrine response in ILC cells, as WNT4 knockdown blocked estrogen-induced proliferation. ILC-LTED cells remained dependent on WNT4 for proliferation, by either maintaining ER function and WNT4 regulation or uncoupling WNT4 from ER and upregulating WNT4 expression. In the latter case, WNT4 expression was driven by activated nuclear factor kappa-B signaling in ILC-LTED cells. In ILC and ILC-LTED cells, WNT4 led to suppression of CDKN1A/p21, which is critical for ILC cell proliferation. CDKN1A knockdown partially reversed the effects of WNT4 knockdown.

CONCLUSIONS

WNT4 drives a novel signaling pathway in ILC cells, with a critical role in estrogen-induced growth that may also mediate endocrine resistance. WNT4 signaling may represent a novel target to modulate endocrine response specifically for patients with ILC.

Wnt Signaling in Renal Cell Carcinoma

Renal cell carcinoma (RCC) accounts for 90% of all kidney cancers. Due to poor diagnosis, high resistance to the systemic therapies and the fact that most RCC cases occur sporadically, current research switched its focus on studying the molecular mechanisms underlying RCC. The aim is the discovery of new effective and less toxic anti-cancer drugs and novel diagnostic markers. Besides the PI3K/Akt/mTOR, HGF/Met and VHL/hypoxia cellular signaling pathways, the involvement of the Wnt/β-catenin pathway in RCC is commonly studied. Wnt signaling and its targeted genes are known to actively participate in different biological processes during embryonic development and renal cancer. Recently, studies have shown that targeting this pathway by alternating/inhibiting its intracellular signal transduction can reduce cancer cells viability and inhibit their growth. The targets and drugs identified show promising potential to serve as novel RCC therapeutics and prognostic markers. This review aims to summarize the current status quo regarding recent research on RCC focusing on the involvement of the Wnt/β-catenin pathway and how its understanding could facilitate the identification of potential therapeutic targets, new drugs and diagnostic biomarkers.

Molecular mechanisms associated with 46,XX disorders of sex development

In the female gonad, distinct signalling pathways activate ovarian differentiation while repressing the formation of testes. Human disorders of sex development (DSDs), such as 46,XX DSDs, can arise when this signalling is aberrant. Here we review the current understanding of the genetic mechanisms that control gonadal development, with particular emphasis on those that drive or inhibit ovarian differentiation. We discuss how disruption to these molecular pathways can lead to 46,XX disorders of ovarian development. Finally, we look at recently characterized novel genes and pathways that contribute and speculate how advances in technology will aid in further characterization of normal and disrupted human ovarian development.