Mechanistic study of the anti-excitatory amino acid toxicity of Bushen Zhichan decoction for Parkinson's disease based on the transcriptional regulation of EAAT1 by YY1

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Zhichan decoction (BSZCF) is derived from Liuwei Dihuang Pill, a famous Chinese herbal formula recorded in the book Key to Therapeutics of Children's Diseases. It has been widely used as a basic prescription for nourishing and tonifying the liver and kidneys to treat Parkinson's disease (PD), but its mechanism remains to be explored.

AIM OF THE STUDY

BSZCF, a Chinese herbal formula comprising five herbs: Rehmannia glutinosa (Gaertn.) DC., Dioscorea oppositifolia L., Cornus officinalis Siebold & Zucc., Fallopia multiflora (Thunb.) Haraldson and Cistanche tubulosa (Schenk) Wight, is used clinically to treat PD. In vivo and in vitro experiments were designed to elucidate the mechanism of BSZCF in the protection of dopamine (DA) neurons and the treatment of PD. The toxicity of excitatory amino acids (EAA) may be attenuated by inhibiting the transcription factor Yin Yang 1 (YY1) and up-regulating the expression of excitatory amino acid transporter 1 (EAAT1).

MATERIALS AND METHODS

IN VIVO: After 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was intraperitoneally injected into specific pathogen free (SPF) C57BL/6J mice, model mice were intragastrically given adamantane hydrochloride tablets (AHT) or different doses of BSZCF for 14 days. Both open field and pole-climbing tests were conducted to assess behavioral changes. In vitro: 1-Methyl-4-phe-nylpyridiniumiodide (MPP+)-injured human neuroblastoma cells (SH-SY5Y) were utilized to construct PD cell models. Primary astrocytes were transfected with EAAT1 and YY1 lentiviruses for EAAT1 gene knockout and YY1 gene knockout astrocytes, respectively. The high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of BSZCF was performed to control the quality of blood drugs. The optimal concentration and time of PD cell models treated by BSZCF were determined by the use of Cell Counting Kit-8 (CCK8). Enzyme-linked immunosorbent assay (ELISA) was used for measuring glutamate (Glu) in the peripheral blood and cells of each group. Western blotting (WB) and real-time quantitative polymerase chain reaction (qPCR) were used to detect tyrosine hydroxylase (TH), dopamine transporters (DAT), EAAT1 and YY1 protein and mRNA. After the blockade of EAAT1, immunofluorescence (IF) assay was used to detect the TH protein in each group.

RESULTS

In vivo research showed that BSZCF improved the behavioral symptoms of PD mice, and reduced the death of DA neurons and the level of Glu. The mechanism may be related to the decrease of YY1 expression and the increase of EAAT1 levels. In vitro experiments showed that the anti-excitatory amino acid toxicity of BSZCF was achieved by inhibiting YY1 expression and regulating EAAT1.

CONCLUSIONS

By inhibiting YY1 to increase the expression of EAAT1 and attenuating the toxicity of Glu, BSZCF exerts the effect of protecting DA neurons and treating PD-like symptoms in mice.

Mechanistic insights into the ameliorative effects of Xianglianhuazhuo formula on chronic atrophic gastritis through ferroptosis mediated by YY1/miR-320a/TFRC signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Xianglianhuazhuo formula (XLHZ) has a potential therapeutic effect on chronic atrophic gastritis (CAG). However, the specific molecular mechanism remains unclear.

AIM OF THE STUDY

To evaluate the effect of XLHZ on CAG in vitro and in vivo and its potential mechanisms.

METHODS

A rat model of CAG was established using a composite modeling method, and the pathological changes and ultrastructure of gastric mucosa were observed. YY1/miR-320a/TFRC and ferroptosis-related molecules were detected. An MNNG-induced gastric epithelial cell model was established in vitro to evaluate the inhibitory effect of XLHZ on cell ferroptosis by observing cell proliferation, migration, invasion, apoptosis, and molecules related to ferroptosis. The specific mechanism of action of XLHZ in treating CAG was elucidated by silencing or overexpression of targets.

RESULTS

In vivo experiments showed that XLHZ could improve the pathological status and ultrastructure of gastric mucosa and inhibit ferroptosis by regulating the YY1/miR-320a/TFRC signaling pathway. The results in vitro demonstrated that transfection of miR-320a mimics inhibited cell proliferation, migration, and invasion while promoting cell apoptosis. MiR-320a targeted TFRC and inhibited ferroptosis. Overexpression of TFRC reversed the inhibitory effect of miR-320a overexpression on cell proliferation. The effect of XLHZ was consistent with that of miR-320a. YY1 targeted miR-320a, and its overexpression promoted ferroptosis.

CONCLUSION

XLHZ inhibited ferroptosis by regulating the YY1/miR-320a/TFRC signaling pathway, ultimately impeding the progression of CAG.

YY1 Contributes to the Inflammatory Responses of Mycobacterium tuberculosis-Infected Macrophages Through Transcription Activation-Mediated Upregulation TLR4

Tuberculosis (TB) is a chronic respiratory infectious disease and is induced by Mycobacterium tuberculosis (M.tb) infection. Macrophages serve as the cellular home in immunoreaction against M.tb infection, which is tightly regulated through Toll-like receptor 4 (TLR4) expression. Therefore, this study is designed to explore the role and mechanism of TLR4 in mycobacterial injury in human macrophages (THP-1 cells) after M.tb infection. Cell proliferation and apoptosis were assessed using MTT, EdU, and flow cytometry assays. ELISA kits were utilized to assess the levels of Interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α). The binding between Yin-Yang-1 (YY1) and TLR4 promoter was predicted by JASPAR and verified using Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. M.tb infection might repress THP-1 cell proliferation, and induce cell apoptosis and inflammatory response in a multiplicity of infection (MOI)-dependent manner. Moreover, M.tb infection increased the expression of TLR4 in HTP-1 cells in an MOI-dependent way, and its downregulation might overturn M.tb infection-mediated HTP-1 cell damage and inflammatory response. At the molecular level, YY1 was a transcription factor of TLR4 and promoted TLR4 transcription via binding to its promoter region. Besides, YY1 might activate the NF-kB signaling pathway via regulating TLR4. Meanwhile, TLR4 inhibitor BAY11-7082 might overturn the repression effect of TLR4 on M.tb-infected HTP-1 cell damage. YY1-activated TLR4 might aggravate mycobacterial injury in human macrophages after M.tb infection by the NF-kB pathway, providing a promising therapeutic target for TB treatment.

Brucine alleviates fibroblast-like synoviocytes dysfunction and inflammation by regulating YY1 during rheumatoid arthritis

Brucine is a weak alkaline indole alkaloid with wide pharmacological activities and has been identified to protect against rheumatoid arthritis (RA) process. Circular RNAs (circRNAs) are also reported to be involved in the pathogenesis of RA. Here, we aimed to probe the role and mechanism of Brucine and circ_0139658 in RA progression. The fibroblast-like synoviocytes of RA (RA-FLSs) were isolated for functional analysis. Cell proliferation, apoptosis, invasion, migration, as well as inflammatory response were evaluated by CCK-8 assay, EdU assay, flow cytometry, transwell assay, and ELISA analysis, respectively. qRT-PCR and western blotting analyses were utilized to measure the levels of genes and proteins. The binding between miR-653-5p and circ_0139658 or Yin Yang 1 (YY1), was verified using dual-luciferase reporter and RNA pull-down assays. Brucine suppressed the proliferation, migration, and invasion of RA-FLSs, and alleviated inflammation by reducing the release of pro-inflammatory factors and macrophage M1 polarization. RA-FLSs showed increased circ_0139658 and YY1 levels and decreased miR-653-5p levels. Circ_0139658 is directly bound to miR-653-5p to regulate YY1 expression. Brucine treatment suppressed circ_0139658 and YY1 expression but increased YY1 expression in RA-FLSs. Functionally, circ_0139658 overexpression reversed the suppressing effects of Brucine on RA-FLS dysfunction and inflammation. Moreover, circ_0139658 silencing alleviated the dysfunction and inflammation in RA-FLSs, which were reverted by YY1 overexpression. Brucine suppressed the proliferation, migration, invasion, and inflammation in RA-FLSs by decreasing YY1 via circ_0139658/miR-653-5p axis.

Locus-level L1 DNA methylation profiling reveals the epigenetic and transcriptional interplay between L1s and their integration sites

Long interspersed element 1 (L1) retrotransposons are implicated in human disease and evolution. Their global activity is repressed by DNA methylation, but deciphering the regulation of individual copies has been challenging. Here, we combine short- and long-read sequencing to unveil L1 methylation heterogeneity across cell types, families, and individual loci and elucidate key principles involved. We find that the youngest primate L1 families are specifically hypomethylated in pluripotent stem cells and the placenta but not in most tumors. Locally, intronic L1 methylation is intimately associated with gene transcription. Conversely, the L1 methylation state can propagate to the proximal region up to 300 bp. This phenomenon is accompanied by the binding of specific transcription factors, which drive the expression of L1 and chimeric transcripts. Finally, L1 hypomethylation alone is typically insufficient to trigger L1 expression due to redundant silencing pathways. Our results illuminate the epigenetic and transcriptional interplay between retrotransposons and their host genome.

YY1: a key regulator inhibits gastric cancer ferroptosis and mediating apatinib-resistance

OBJECTIVE

Gastric cancer (GC) stands as a prevalent and deadly global malignancy. Despite its role as a preoperative neoadjuvant therapy, Apatinib's effectiveness is curtailed among GC patients exhibiting elevated YY1 expression. YY1's connection to adverse prognosis, drug resistance, and GC metastasis is established, yet the precise underlying mechanisms remain elusive. This study aims to unravel potential pathogenic pathways attributed to YY1.

DESIGN

Utilizing bioinformatics analysis, we conducted differentially expressed genes, functional annotation, and pathway enrichment analyses, and further validation through cellular and animal experiments.

RESULTS

Higher YY1 expression correlated with diminished postoperative progression-free survival (PFS) and disease-specific survival (DSS) rates in TCGA analysis, identifying YY1 as an independent DSS indicator in gastric cancer (GC) patients. Notably, YY1 exhibited significantly elevated expression in tumor tissues compared to adjacent normal tissues. Bioinformatics analysis revealed noteworthy differentially expressed genes (DEGs), transcriptional targets, factors, and co-expressed genes associated with YY1. LASSO Cox analysis unveiled Transferrin as a prospective pivotal protein regulated by YY1, with heightened expression linked to adverse DSS and PFS outcomes. YY1's role in governing the p53 signaling pathway and ferroptosis in GC cells was further elucidated. Moreover, YY1 overexpression dampened immune cell infiltration within GC tumors. Additionally, YY1 overexpression hindered GC cell ferroptosis and mediated Apatinib resistance via the p53 pathway. Remarkably, IFN-a demonstrated efficacy in reversing Apatinib resistance and immune suppression in GC tissues.

CONCLUSIONS

Our findings underscore the pivotal role of YY1 in driving GC progression and influencing prognosis, thus pinpointing it as a promising therapeutic target to enhance patient outcomes.

Functional SNPs in SYISL promoter significantly affect muscle fiber density and muscle traits in pigs

Our previous studies showed that SYISL is a negative regulator of muscle growth and regeneration in mice, pigs and humans. SYISL knockout resulted in an increase in the density of muscle fibers and muscle growth. However, it is unclear whether there are natural mutations in pig SYNPO2 intron sense-overlapping lncRNA (pSYISL) that affect the expression of pSYISL and muscle growth traits. In this study, three SNPs in exons and six SNPs within the promoter of pSYISL were identified. Association analysis showed that the two SNPs in exons are significantly associated with loin muscle area (p < 0.05); the six SNPs in the promoter that show complete linkage are significantly associated with live backfat thickness and live loin muscle area in American Large White pigs. Bioinformatics and luciferase reporter assays as well as in vitro binding experiments indicated that the mutation of SNP rs702045770 (g.539G>A) leads to the loss of YY1 binding to the promoter, thus affecting the expression level of pSYISL, and we found that Jiangshan Black pigs with genotype GG have a higher expression level of pSYISL than genotype AA individuals, but the muscle fiber density was significantly lower than in genotype AA individuals. Furthermore, the association analysis showed that the carcass backfat thickness of genotype GG of SNP rs702045770 was significantly higher than that of other genotypes in (Pietrain × Duroc) × (Landrace × Yorkshire) crossbred pigs (p < 0.05). The glycolytic potential of genotype GG was significantly higher than that of other genotypes (p < 0.05). These results provide novel insight into the identification of functional SNPs in non-coding genomic regions.

Silibinin suppresses glioblastoma cell growth, invasion, stemness, and glutamine metabolism by YY1/SLC1A5 pathway

Background

Silibinin has been found to inhibit glioblastoma (GBM) progression. However, the underlying molecular mechanism by which Silibinin regulates GBM process remains unclear.

Methods

GBM cell proliferation, apoptosis, invasion, and stemness are assessed by cell counting kit-8 assay, EdU assay, flow cytometry, transwell assay, and sphere formation assay. Western blot is used to measure the protein expression levels of apoptosis-related markers, solute carrier family 1 member 5 (SLC1A5), and Yin Yang-1 (YY1). Glutamine consumption, glutamate production, and α-ketoglutarate production are detected to evaluate glutamine metabolism in cells. Also, SLC1A5 and YY1 mRNA levels are examined using quantitative real-time PCR. Chromatin immunoprecipitation assay and dual-luciferase reporter assay are used to detect the interaction between YY1 and SLC1A5. Mice xenograft models are constructed to explore Silibinin roles in vivo.

Results

Silibinin inhibits GBM cell proliferation, invasion, stemness, and glutamine metabolism, while promotes apoptosis. SLC1A5 is upregulated in GBM and its expression is decreased by Silibinin. SLC1A5 overexpression abolishes the anti-tumor effect of Silibinin in GBM cells. Transcription factor YY1 binds to SLC1A5 promoter region to induce SLC1A5 expression, and the inhibition effect of YY1 knockdown on GBM cell growth, invasion, stemness, and glutamine metabolism can be reversed by SLC1A5 overexpression. In addition, Silibinin reduces GBM tumor growth by regulating YY1/SLC1A5 pathway.

Conclusion

Silibinin plays an anti-tumor role in GBM process, which may be achieved via inhibiting YY1/SLC1A5 pathway.

Vitamin D binding protein (VDBP) hijacks twist1 to inhibit vasculogenic mimicry in hepatocellular carcinoma

Rationale: Vitamin D (VD) has been suggested to have antitumor effects, however, research on the role of its transporter vitamin D-binding protein (VDBP, gene name as GC) in tumors is limited. In this study, we demonstrated the mechanism underlying the inhibition of vasculogenic mimicry (VM) by VDBP in hepatocellular carcinoma (HCC) and proposed an anti-tumor strategy of combining anti-PD-1 therapy with VD. Methods: Three-dimensional cell culture models and mice with hepatocyte-specific GC deletion were utilized to study the correlation between VDBP expression and VM. A patient-derived tumor xenograft (PDX) model was further applied to validate the therapeutic efficacy of VD in combination with an anti-PD-1 drug. Results: The study revealed that VDBP expression is negatively correlated with VM in HCC patients and elevated VDBP expression is associated with a favorable prognosis. The mechanism studies suggested VDBP hindered the binding of Twist1 on the promoter of VE-cadherin by interacting with its helix-loop-helix DNA binding domain, ultimately leading to the inhibition of VM. Furthermore, VD facilitated the translocation of the vitamin D receptor (VDR) into the nucleus where VDR interacts with Yin Yang 1 (YY1), leading to the transcriptional activation of VDBP. We further demonstrated that the combination of VD and anti-PD-1 led to an improvement in the anti-tumor efficacy of an anti-PD-1 drug. Conclusion: Collectively, we identified VDBP as an important prognostic biomarker in HCC patients and uncovered it as a therapeutic target for enhancing the efficacy of immune therapy.

SMURF1 activates the cGAS/STING/IFN-1 signal axis by mediating YY1 ubiquitination to accelerate the progression of lupus nephritis

Aggravated endoplasmic reticulum stress (ERS) and apoptosis in podocytes play an important role in lupus nephritis (LN) progression, but its mechanism is still unclear. Herein, the role of SMURF1 in regulating podocytes apoptosis and ERS during LN progression were investigated. MRL/lpr mice was used as LN model in vivo. HE staining was performed to analyze histopathological changes. Mouse podocytes (MPC5 cells) were treated with serum IgG from LN patients (LN-IgG) to construct LN model in vitro. CCK8 assay was adopted to determine the viability. Cell apoptosis was measured using flow cytometry and TUNEL staining. The interactions between SMURF1, YY1 and cGAS were analyzed using ChIP and/or dual-luciferase reporter gene and/or Co-IP assays. YY1 ubiquitination was analyzed by ubiquitination analysis. Our results found that SMURF1, cGAS and STING mRNA levels were markedly increased in serum samples of LN patients, while YY1 was downregulated. YY1 upregulation reduced LN-IgG-induced ERS and apoptosis in podocytes. Moreover, SMURF1 upregulation reduced YY1 protein stability and expression by ubiquitinating YY1 in podocytes. Rescue studies revealed that YY1 knockdown abrogated the inhibition of SMURF1 downregulation on LN-IgG-induced ERS and apoptosis in podocytes. It was also turned out that YY1 alleviated podocytes injury in LN by transcriptional inhibition cGAS/STING/IFN-1 signal axis. Finally, SMURF1 knockdown inhibited LN progression in vivo. In short, SMURF1 upregulation activated the cGAS/STING/IFN-1 signal axis by regulating YY1 ubiquitination to facilitate apoptosis in podocytes during LN progression.

Interplay between lncRNA RP11-367G18.1 variant 2 and YY1 plays a vital role in hypoxia-mediated gene expression and tumorigenesis

BACKGROUND

The hypoxia-responsive long non-coding RNA, RP11-367G18.1, has recently been reported to induce histone 4 lysine 16 acetylation (H4K16Ac) through its variant 2; however, the underlying molecular mechanism remains poorly understood.

METHODS

RNA pull-down assay and liquid chromatography-tandem mass spectrometry were performed to identify RP11-367G18.1 variant 2-binding partner. The molecular events were examined utilizing western blot analysis, real-time PCR, luciferase reporter assay, chromatin immunoprecipitation, and chromatin isolation by RNA purification assays. The migration, invasion, soft agar colony formation, and in vivo xenograft experiments were conducted to evaluate the impact of RP11-367G18.1 variant 2-YY1 complex on tumor progression.

RESULTS

In this study, RNA sequencing data revealed that hypoxia and RP11-367G18.1 variant 2 co-regulated genes were enriched in tumor-related pathways. YY1 was identified as an RP11-367G18.1 variant 2-binding partner that activates the H4K16Ac mark. YY1 was upregulated under hypoxic conditions and served as a target gene for hypoxia-inducible factor-1α. RP11-367G18.1 variant 2 colocalized with YY1 and H4K16Ac in the nucleus under hypoxic conditions. Head and neck cancer tissues had higher levels of RP11-367G18.1 and YY1 which were associated with poor patient outcomes. RP11-367G18.1 variant 2-YY1 complex contributes to hypoxia-induced epithelial-mesenchymal transition, cell migration, invasion, and tumorigenicity. YY1 regulated hypoxia-induced genes dependent on RP11-367G18.1 variant 2.

CONCLUSIONS

RP11-367G18.1 variant 2-YY1 complex mediates the tumor-promoting effects of hypoxia, suggesting that this complex can be targeted as a novel therapeutic strategy for cancer treatment.

Epigenetic regulation of enhancer of zeste homolog 2 (EZH2) -Yin Yang 1 (YY1) axis in cancer

In accordance with the World Health Organization, cancer is the second leading cause of death in patients. In recent years, the number of cancer patients has been growing, and the occurrence of cancer in people is becoming more common, primarily due to lifestyle factors. Yin Yang 1 (YY1) is a transcription factor that is widespread throughout. It is a zinc finger protein, falling under the GLI-Kruppel class. YY1 is known to regulate transcriptional activation and repression of various genes associated with different cellular processes such as DNA repair, autophagy, cell survival and apoptosis, and cell division. Meanwhile, EZH2 is a histone-lysine N-methyltransferase enzyme encoded by gene 7 in humans. Its main function involves catalyzing the addition of methyl groups to histone H3 at lysine 27 (H3K27me3), and it is involved in regulating CD8 + T cell fate and function. It is a subunit of a Polycomb repressor complex 2 (PRC2). The EZH2 gene encodes for an enzyme that is involved in histone methylation and transcriptional repression. It adds methyl groups to lysine 27 on histone H3 (H3K27me3) with the help of the cofactor S-adenosyl-L-methionine. In addition to its role in epigenetic regulation, EZH2 also acts as a regulator of CD8+ T cell fate and function. EZH2 has been implicated in T Cell Receptor (TCR) signaling via the regulation of actin polymerization. In fact, EZH2 is involved in numerous signaling pathways that lead to tumorigenesis. EZH2 is mutated in cancer and shows overexpression. Due to its mutation and overexpression, the cells that help combat cancer are suppressed and carcinogenicity is promoted. The association of EZH2 and YY1 poses an intriguing mechanism in relation to cancer.

Assessing the dynamics and macromolecular interactions of the intrinsically disordered protein YY1

YY1 is a ubiquitously expressed, intrinsically disordered transcription factor involved in neural development. The oligomeric state of YY1 varies depending on the environment. These structural changes may alter its DNA binding ability and hence its transcriptional activity. Just as YY1's oligomeric state can impact its role in transcription, so does its interaction with other proteins such as FOXP2. The aim of this work is to study the structure and dynamics of YY1 so as to determine the influence of oligomerisation and associations with FOXP2 on its DNA binding mechanism. The results confirm that YY1 is primarily a disordered protein, but it does consist of certain specific structured regions. We observed that YY1 quaternary structure is a heterogenous mixture of oligomers, the overall size of which is dependent on ionic strength. Both YY1 oligomerisation and its dynamic behaviour are further subject to changes upon DNA binding, whereby increases in DNA concentration result in a decrease in the size of YY1 oligomers. YY1 and the FOXP2 forkhead domain were found to interact with each other both in isolation and in the presence of YY1-specific DNA. The heterogeneous, dynamic multimerisation of YY1 identified in this work is, therefore likely to be important for its ability to make heterologous associations with other proteins such as FOXP2. The interactions that YY1 makes with itself, FOXP2 and DNA form part of an intricate mechanism of transcriptional regulation by YY1, which is vital for appropriate neural development.

CENPA functions as a transcriptional regulator to promote hepatocellular carcinoma progression via cooperating with YY1

The centromere proteins (CENPs), a critical mitosis-related protein complexes, are involved in the kinetochore assembly and chromosome segregation. In this study, we identified that CENPA was significantly up-regulated in HCC and highly expressed CENPA correlated with poor prognosis for HCC patients. Knockdown of CENPA inhibited HCC cell proliferation and tumor growth in vitro and in vivo. Mechanistically, CENPA transcriptionally activated and cooperated with YY1 to drive the expression of cyclin D1 (CCND1) and neuropilin 2 (NRP2). Moreover, we identified that CENPA can be lactylated at lysine 124 (K124). The lactylation of CENPA at K124 promotes CENPA activation, leading to enhanced expression of its target genes. In summary, CENPA function as a transcriptional regulator to promote HCC via cooperating with YY1. Targeting the CENPA-YY1-CCND1/NRP2 axis may provide candidate therapeutic targets for HCC.

Cross-Talks between RKIP and YY1 through a Multilevel Bioinformatics Pan-Cancer Analysis

Recent studies suggest that PEBP1 (also known as RKIP) and YY1, despite having distinct molecular functions, may interact and mutually influence each other's activity. They exhibit reciprocal control over each other's expression through regulatory loops, prompting the hypothesis that their interplay could be pivotal in cancer advancement and resistance to drugs. To delve into this interplay's functional characteristics, we conducted a comprehensive analysis using bioinformatics tools across a range of cancers. Our results confirm the association between elevated YY1 mRNA levels and varying survival outcomes in diverse tumors. Furthermore, we observed differing degrees of inhibitory or activating effects of these two genes in apoptosis, cell cycle, DNA damage, and other cancer pathways, along with correlations between their mRNA expression and immune infiltration. Additionally, YY1/PEBP1 expression and methylation displayed connections with genomic alterations across different cancer types. Notably, we uncovered links between the two genes and different indicators of immunosuppression, such as immune checkpoint blockade response and T-cell dysfunction/exclusion levels, across different patient groups. Overall, our findings underscore the significant role of the interplay between YY1 and PEBP1 in cancer progression, influencing genomic changes, tumor immunity, or the tumor microenvironment. Additionally, these two gene products appear to impact the sensitivity of anticancer drugs, opening new avenues for cancer therapy.

Yin Yang 1 controls cerebellar astrocyte maturation

Diverse subpopulations of astrocytes tile different brain regions to accommodate local requirements of neurons and associated neuronal circuits. Nevertheless, molecular mechanisms governing astrocyte diversity remain mostly unknown. We explored the role of a zinc finger transcription factor Yin Yang 1 (YY1) that is expressed in astrocytes. We found that specific deletion of YY1 from astrocytes causes severe motor deficits in mice, induces Bergmann gliosis, and results in simultaneous loss of GFAP expression in velate and fibrous cerebellar astrocytes. Single cell RNA-seq analysis showed that YY1 exerts specific effects on gene expression in subpopulations of cerebellar astrocytes. We found that although YY1 is dispensable for the initial stages of astrocyte development, it regulates subtype-specific gene expression during astrocyte maturation. Moreover, YY1 is continuously needed to maintain mature astrocytes in the adult cerebellum. Our findings suggest that YY1 plays critical roles regulating cerebellar astrocyte maturation during development and maintaining a mature phenotype of astrocytes in the adult cerebellum.

Risk SNP in a transcript of RP11-638I2.4 increases lncRNA-YY1 interaction and pancreatic cancer susceptibility

Tens of thousands of long non-coding RNAs (lncRNAs) have been identified through RNA-seq analysis, but the biological and pathological significance remains unclear. By integrating the genome-wide lncRNA data with a cross-ancestry meta-analysis of PDAC GWASs, we depicted a comprehensive atlas of pancreatic ductal adenocarcinoma (PDAC)-associated lncRNAs, containing 1,204 lncRNA (445 novel lncRNAs and 759 GENCODE annotated lncRNAs) and 4,368 variants. Furthermore, we found that PDAC-associated lncRNAs could function by altering chromatin activity, transcription factors, and RNA-binding proteins binding affinity. Importantly, genetic variants linked to PDAC are preferentially found at PDAC-associated lncRNA regions, supporting the biological and clinical relevance of PDAC-associated lncRNAs. Finally, we prioritized a novel transcript (MICT00000110172.1) of RP11-638I2.4 as a potential tumor promoter. MICT00000110172.1 is able to reinforce the interaction with YY1, which could reverse the effect of YY1 on pancreatic cancer cell cycle arrest to promote the pancreatic cancer growth. G > A change at rs2757535 in the second exon of MICT00000110172.1 induces a spatial structural change and creates a target region for YY1 binding, which enforces the effect of MICT00000110172.1 in an allele-specific manner, and thus confers susceptibility to tumorigenesis. In summary, our results extend the repertoire of PDAC-associated lncRNAs that could act as a starting point for future functional explorations, and the identification of lncRNA-based target therapy.

METTL3 facilitates multiple myeloma tumorigenesis by enhancing YY1 stability and pri-microRNA-27 maturation in m6A-dependent manner

Multiple myeloma (MM) is a pernicious plasma cell disorder and has a poor prognosis. N6-methyladenosine (m6A) is an abundant epigenetic RNA modification and is important in cancer progression. Nevertheless, the function of m6A and its regulator METTL3 in MM are rarely reported. Here, we identified the m6A "writers", METTL3, was enhanced in MM and found that Yin Yang 1 (YY1) and primary-miR-27a-3p were the potential target for METTL3. METTL3 promoted primary-miR-27a-3p maturation and YY1 mRNA stability in an m6A manner. YY1 also was found to facilitate miR-27a-3p transcription. METTL3 affected the growth, apoptosis, and stemness of MM cells through accelerating the stability of YY1 mRNA and the maturation of primary-miR-27a-3p in vitro and in vivo. Our results reveal the key function of the METTL3/YY1/miR-27a-3p axis in MM and may provide fresh insights into MM therapy.

Competition between p53 and YY1 determines PHGDH expression and malignancy in bladder cancer

PURPOSE

Serine metabolism is frequently dysregulated in many types of cancers and the tumor suppressor p53 is recently emerging as a key regulator of serine metabolism. However, the detailed mechanism remains unknown. Here, we investigate the role and underlying mechanisms of how p53 regulates the serine synthesis pathway (SSP) in bladder cancer (BLCA).

METHODS

Two BLCA cell lines RT-4 (WT p53) and RT-112 (p53 R248Q) were manipulated by applying CRISPR/Cas9 to examine metabolic differences under WT and mutant p53 status. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and non-targeted metabolomics analysis were adopted to identify metabolomes changes between WT and p53 mutant BLCA cells. Bioinformatics analysis using the cancer genome atlas and Gene Expression Omnibus datasets and immunohistochemistry (IHC) staining was used to investigate PHGDH expression. Loss-of-function of PHGDH and subcutaneous xenograft model was adopted to investigate the function of PHGDH in mice BLCA. Chromatin immunoprecipitation (Ch-IP) assay was performed to analyze the relationships between YY1, p53, SIRT1 and PHGDH expression.

RESULTS

SSP is one of the most prominent dysregulated metabolic pathways by comparing the metabolomes changes between wild-type (WT) p53 and mutant p53 of BLCA cells. TP53 gene mutation shows a positive correlation with PHGDH expression in TCGA-BLCA database. PHGDH depletion disturbs the reactive oxygen species homeostasis and attenuates the xenograft growth in the mouse model. Further, we demonstrate WT p53 inhibits PHGDH expression by recruiting SIRT1 to the PHGDH promoter. Interestingly, the DNA binding motifs of YY1 and p53 in the PHGDH promoter are partially overlapped which causes competition between the two transcription factors. This competitive regulation of PHGDH is functionally linked to the xenograft growth in mice.

CONCLUSION

YY1 drives PHGDH expression in the context of mutant p53 and promotes bladder tumorigenesis, which preliminarily explains the relationship between high-frequency mutations of p53 and dysfunctional serine metabolism in bladder cancer.

Yin Yang 1 promotes the neuroendocrine differentiation of prostate cancer cells via the non-canonical WNT pathway (FYN/STAT3)

BACKGROUND

A growing number of studies have shown that Yin Yang 1 (YY1) promotes the development of multiple tumours. The purpose of the current study was to determine the mechanism by which YY1 mediates neuroendocrine differentiation of prostate cancer (NEPC) cells undergoing cellular plasticity.

METHODS

Using the Cancer Genome Atlas and Gene Expression Omnibus (GEO) databases, we bioinformatically analyzed YY1 expression in prostate cancer (PCa). Aberrant YY1 expression was validated in different PCa tissues and cell lines via quantitative reverse transcription polymerase chain reaction, western blotting, and immunohistochemistry. In vivo and in vitro functional assays verified the oncogenicity of YY1 in PCa. Further functional assays showed that ectopic expression of YY1 promoted cellular plasticity in PCa cells via epithelial-mesenchymal transition induction and neuroendocrine differentiation.

RESULTS

Androgen deprivation therapy induced a decrease in YY1 protein ubiquitination, enhanced its stability, and thus enhanced the transcriptional activity of FZD8. Castration enhanced FZD8 binding to Wnt9A and mediated cellular plasticity by activating the non-canonical Wnt (FZD8/FYN/STAT3) pathway.

CONCLUSIONS

We identified YY1 as a novel dysregulated transcription factor that plays an important role in NEPC progression in this study. We believe that an in-depth investigation of the mechanism underlying YY1-mediated disease may lead to improved NEPC therapies.

YY1 is regulated by ALKBH5-mediated m6A modification and promotes autophagy and cancer progression through targeting ATG4B

YY1 affects tumorigenesis and metastasis in multiple ways. However, the function of YY1 and the potential mechanisms through which it operates in gastric cancer (GC) progression by regulating autophagy remains poorly understood. This study aimed to assess the essential transcription factors (TFs) involved in autophagy regulation in GC. Western blot, RFP-GFP-LC3 double fluorescence and transmission electron microscopy (TEM) assays were used to probe autophagy activity in GC cells. Methylated RNA immunoprecipitation (MeRIP) was utilized to evaluate the ALKBH5-regulated m6A levels of YY1. Gain- and loss-of-function assays were employed in the scrutiny of the biological effects of the ALKBH5/YY1/ATG4B axis on cancer cell proliferation and invasion abilities in vitro. Per the findings, YY1 was identified as a crucial transcriptional activator of cancer autophagy-related genes and promoted the proliferation and aggressiveness of cancer cells associated with enhanced ATG4B-mediated autophagy. However, ectopic ALKBH5 expression abolished the YY1-induced effect via m6A modification. Importantly, YTHDF1 facilitated the mRNA stability of YY1 through m6A recognition. Collectively, this study found that YY1 was regulated by ALKBH5 and YTHDF1-mediated m6A modification and served as an autophagy-dependent tumor driver to accelerate cancer progression through ATG4B transactivation, providing an exploitable therapeutic target for GC.

Identification and functional validation of an enhancer variant in the 9p21.3 locus associated with glaucoma risk and elevated expression of p16INK4a

Glaucoma is a leading cause of irreversible blindness, with advanced age being the single most significant risk factor. However, the mechanisms underlying the relationship between aging and glaucoma remain unclear. Genome-wide association studies (GWAS) have successfully identified genetic variants strongly associated with increased glaucoma risk. Understanding how these variants function in pathogenesis is crucial for translating genetic associations into molecular mechanisms and, ultimately, clinical applications. The chromosome 9p21.3 locus is among the most replicated glaucoma risk loci discovered by GWAS. Nonetheless, the absence of protein-coding genes in the locus makes interpreting the disease association challenging, leaving the causal variant and molecular mechanism elusive. In this study, we report the identification of a functional glaucoma risk variant, rs6475604. By employing computational and experimental methods, we demonstrated that rs6475604 resides in a repressive regulatory element. Risk allele of rs6475604 disrupts the binding of YY1, a transcription factor known to repress the expression of a neighboring gene in 9p21.3, p16INK4A, which plays a crucial role in cellular senescence and aging. These findings suggest that the glaucoma disease variant contributes to accelerated senescence, providing a molecular link between glaucoma risk and an essential cellular mechanism for human aging.

Downregulation of MicroRNA-29-3p Following Percutaneous Coronary Intervention: An Implication of YY1/IRAK1 Pathway in the Post-Vascular Injury Inflammation

This study explored the expression of microRNA (miR)-29b-3p following percutaneous coronary intervention (PCI) and the implication of its downstream Yin Yang 1 (YY1)/interleukin (IL)-1 receptor-associated kinase 1 (IRAK1) pathway in post-vascular injury inflammation. Blood samples were collected for analysis of plasma miR-29b-3p from patients with acute coronary syndrome before surgery, 1 day after PCI, and 30 days after PCI. Lipopolysaccharide (LPS)-treated human coronary artery endothelial cells (HCAECs) were transfected with miR-29b-3p mimic/inhibitor or YY1 shRNA and underwent viability tests. Enzyme-linked immunosorbent assay was performed to detect the levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), IL-1β, IL-6, and tumor necrosis factor (TNF)-α in serum and cell culture supernatant. Dual-luciferase reporter and RNA/chromatin immunoprecipitation were used to confirm the targeting relationships among miR-29b-3p, YY1, and IRAK1. A rat model of intraluminal injury of the common femoral artery was established to address the role of miR-29b-3p and relevant mechanisms. miR-29b-3p was lowly expressed, and sVCAM-1, IL-1β, IL-6, and TNF-α were upregulated 1 day after PCI and 24 h after LPS treatment. miR-29b-3p overexpression or YY1 knockdown alleviated LPS-induced inflammatory responses and improved the viability of HCAECs. miR-29b-3p inhibition aggravated LPS-induced inflammatory injury in HCAECs. miR-29b-3p bound to YY1 mRNA and inhibited the expression of YY1 protein. YY1 bound to the IRAK1 promoter and activated the transcription of IRAK1. Upregulation of miR-29b-3p suppressed the inflammatory response after intraluminal injury of the common femoral artery in rats. In conclusion, dysregulation of the YY1/IRAK1 pathway via miR-29b-3p downregulation may be implicated in post-vascular injury inflammation.

Role of YY1 in the Regulation of Anti-Apoptotic Gene Products in Drug-Resistant Cancer Cells

Cancer is a leading cause of death among the various diseases encountered in humans. Cancer is not a single entity and consists of numerous different types and subtypes that require various treatment regimens. In the last decade, several milestones in cancer treatments were accomplished, such as specific targeting agents or revitalizing the dormant anti-tumor immune response. These milestones have resulted in significant positive clinical responses as well as tumor regression and the prolongation of survival in subsets of cancer patients. Hence, in non-responding patients and non-responding relapsed patients, cancers develop intrinsic mechanisms of resistance to cell death via the overexpression of anti-apoptotic gene products. In parallel, the majority of resistant cancers have been reported to overexpress a transcription factor, Yin Yang 1 (YY1), which regulates the chemo-immuno-resistance of cancer cells to therapeutic anticancer cytotoxic agents. The relationship between the overexpression of YY1 and several anti-apoptotic gene products, such as B-cell lymphoma 2 protein (Bcl-2), B-cell lymphoma extra-large (Bcl-xL), myeloid cell leukemia 1 (Mcl-1) and survivin, is investigated in this paper. The findings demonstrate that these anti-apoptotic gene products are regulated, in part, by YY1 at the transcriptional, epigenetic, post-transcriptional and translational levels. While targeting each of the anti-apoptotic gene products individually has been examined and clinically tested for some, this targeting strategy is not effective due to compensation by other overexpressed anti-apoptotic gene products. In contrast, targeting YY1 directly, through small interfering RNAs (siRNAs), gene editing or small molecule inhibitors, can be therapeutically more effective and generalized in YY1-overexpressed resistant cancers.

Yin Yang 1 suppresses tumor invasion and metastasis in nasopharyngeal carcinoma by negatively regulating eIF4E transcriptional activity and expression

Tumor metastasis is a leading cause of death in nasopharyngeal carcinoma (NPC) patients. Previous research has identified that transcription factor Yin Yang 1 (YY1) acts as a tumor suppressor that inhibits cell proliferation and tumor growth in NPC; however, the role and the molecular mechanisms of YY1 in NPC invasion and metastasis remain unclear. In this study, we discovered that YY1 could inhibit the migration and invasion of NPC cells in vitro as well as NPC xenograft tumor metastasis in vivo. Furthermore, we identified eIF4E as a direct downstream target of YY1, and YY1 could negatively regulate the expression of eIF4E at transcriptional level. Moreover, we found that eIF4E promoted the migration and invasion of NPC cells as well as NPC lung metastasis, suggesting its potential as a pro-metastatic mediator in NPC. Importantly, restoring eIF4E expression could partially reverse the inhibitory effects of YY1 on NPC malignancy. In consistent with these findings, the expression of YY1 was downregulated while eIF4E was upregulated in NPC patients with metastasis, and there was a negative correlation between YY1 and eIF4E expression. Collectively, our results indicate that YY1 suppresses the invasion and metastasis of NPC by negatively regulating eIF4E transcription. Therefore, targeting the YY1/eIF4E transcriptional axis could be a potential therapeutic strategy for the treatment of patients with NPC.

YY1 Knockdown Relieves the Differentiation Block and Restores Apoptosis in AML Cells

In this study we analyzed the expression of Yin and Yang 1 protein (YY1), a member of the noncanonical PcG complexes, in AML patient samples and AML cell lines and the effect of YY1 downregulation on the AML differentiation block. Our results show that YY1 is significantly overexpressed in AML patient samples and AML cell lines and that YY1 knockdown relieves the differentiation block. YY1 downregulation in two AML cell lines (HL-60 and OCI-AML3) and one AML patient sample restored the expression of members of the CEBP protein family, increased the expression of extrinsic growth factors/receptors and surface antigenic markers, induced morphological cell characteristics typical of myeloid differentiation, and sensitized cells to retinoic acid treatment and to apoptosis. Overall, our data show that YY1 is not a secondary regulator of myeloid differentiation but that, if overexpressed, it can play a predominant role in myeloid differentiation block.

Decidual macrophages derived NO downregulates PD-L1 in trophoblasts leading to decreased Treg cells in recurrent miscarriage

Introduction

Placental trophoblasts contribute to regulatory T (Treg) function via the programmed cell death-1 (PD-1)/PD-1 ligand 1 (PD-L1) pathway during normal pregnancy. Decreased expression of PD-L1 in trophoblasts was closely associated with Treg deficiency in the development of pregnancy failure. Thus, targeting PD-L1 might be a novel therapy to prevent pregnancy loss. However, the mechanisms for modulating the expression of PD-L1 in trophoblasts are an enigma.

Methods

The proportion of decidual Treg cells, and the profile of decidual macrophages (DMs) sampled from women with normal pregnancy (NP) and recurrent miscarriage (RM) were evaluated by flow cytometry. The expression of Yin and Yang 1 protein (YY1) and PD-L1 in human villous were measured by Immunohistochemistry (IHC), qRT-PCR and western blot. The determination of soluble PD-L1 (sPD-L1) in serum from NP and RM, and trophoblast conditioned media (TCM) was performed by the PD-L1 SimpleStep ELISA kit. Knockdown of YY1 was processed in the human trophoblast derived cell lines, HTR-8 and Bewo, with siYY1 transfection. Peripheral naïve CD4⁺ T cells were isolated from women with NP for the in vitro culture. The percentages of Treg cells differentiated from peripheral naïve CD4⁺ T cells were measured by flow cytometry. The interaction between YY1 and CD274 was proved by CHIP. The expression of inducible nitric oxide synthase (iNOS) in decidua was evaluated by IHC. The level of NO in serum from women with NP and RM was determined by the Griess reagent system. The effects of NO on YY1 were determined by the in vitro culture of HTR-8 cells with the NO donor, SNAP. The in vivo model comprising twelve pregnant mice and underwent different treatment. The percentages of Treg cells in murine uterus were measured by flow cytometry. Similarly, Western blot and IHC were performed to determine the expression of YY1 and PD-L1 in murine placenta.

Results

Decreased expression of YY1 and PD-L1 in trophoblasts and lower proportion of decidual Treg cells were observed in patients with RM. Knockdown of YY1 contributes to a lower expression of YY1 and PD-L1. Soluble PD-L1 in the supernatant from HTR-8 cells was also decreased with siYY1 administration. Lower Treg differentiation was observed in the presence of supernatant from HTR-8 cells treated with siYY1. CHIP analysis revealed that endogenous YY1 directly occupied the promoter region of the CD274 (PD-L1) gene. Accompanied with increased M1 DMs, higher NO was observed in serum sampled from patients with RM. In the presence of Reduced expression of YY1 and PD-L1 was observed in HTR-8 cells with the treatment of SNAP. Furthermore, less Treg differentiation was observed with SNAP treated TCM. Moreover, our in vivo data found that YY1 deficiency was associated with decreased PD-L1, which further resulting in less Treg differentiation and Treg deficiency at the maternal-fetal interface and increased embryo loss.

Discussion

Our work found the modulatory capacity of YY1 on PD-L1 in trophoblasts during early pregnancy. Furthermore, reduced YY1 was supposed resulting from higher levels of NO produced from the M1 DMs in RM.

Prognostic Implication of YY1 and CP2c Expression in Patients with Primary Breast Cancer

Yin Yang 1 (YY1) is a transcription factor that regulates epigenetic pathways and protein modifications. CP2c is a transcription factor that functions as an oncogene to regulate cell proliferation. YY1 is known to interact with CP2c to suppress CP2c's transcriptional activity. This study aimed to investigate YY1 and CP2c expression in breast cancer and prognostic implications. In this study, YY1 and CP2c expression was evaluated using immunohistochemical staining, Western blot and RT-PCR assays. Of 491 patients with primary breast cancer, 138 patients showed YY1 overexpression. Luminal subtype and early stage were associated with overexpression (p < 0.001). After a median follow-up of 68 months, YY1 overexpression was found to be associated with a better prognosis (disease-free survival rates of 92.0% vs. 79.2%, p = 0.014). In Cox proportional hazards model, YY1 overexpression functioned as an independent prognostic factor after adjustment of hormone receptor/HER2 status and tumor size (hazard ratio of 0.50, 95% CI 0.26-0.98, p = 0.042). Quantitative analysis of YY1 and CP2c protein expression in tumors revealed a negative correlation between them. In conclusion, YY1 overexpression is a favorable prognostic biomarker in patients with breast cancer, and it has a negative correlation with CP2c at the protein level.

Dynamic nucleosome remodeling mediated by YY1 underlies early mouse development

Nucleosome positioning can alter the accessibility of DNA-binding proteins to their cognate DNA elements, and thus its precise control is essential for cell identity and function. Mammalian preimplantation embryos undergo temporal changes in gene expression and cell potency, suggesting the involvement of dynamic epigenetic control during this developmental phase. However, the dynamics of nucleosome organization during early development are poorly understood. In this study, using a low-input MNase-seq method, we show that nucleosome positioning is globally obscure in zygotes but becomes well defined during subsequent development. Down-regulation of the chromatin assembly in embryonic stem cells can partially reverse nucleosome organization into a zygote-like pattern, suggesting a possible link between the chromatin assembly pathway and fuzzy nucleosomes in zygotes. We also reveal that YY1, a zinc finger-containing transcription factor expressed upon zygotic genome activation, regulates the de novo formation of well-positioned nucleosome arrays at the regulatory elements through identifying YY1-binding sites in eight-cell embryos. The YY1-binding regions acquire H3K27ac enrichment around the eight-cell and morula stages, and YY1 depletion impairs the morula-to-blastocyst transition. Thus, our study delineates the remodeling of nucleosome organization and its underlying mechanism during early mouse development.

eIF3a sustains non-small cell lung cancer stem cell-like properties by promoting YY1-mediated transcriptional activation of β-catenin

Cancer stem cells (CSCs) are the leading cause of recurrence and poor prognosis in non-small cell lung cancer (NSCLC). Eukaryotic translation initiation factor 3a (eIF3a) participates in many tumor development processes, such as metastasis, therapy resistance, and glycolysis, all of which are closely associated with the presence of CSCs. However, whether eIF3a maintains NSCLC-CSC-like properties remains to be elucidated. In this study, eIF3a was highly expressed in lung cancer tissues and was linked to poor prognosis. eIF3a was also highly expressed in CSC-enriched spheres compared with adherent monolayer cells. Moreover, eIF3a is required for NSCLC stem cell-like traits maintenance in vitro and in vivo. Mechanistically, eIF3a activates the Wnt/β-catenin signaling pathway, promoting the transcription of cancer stem cell markers. Specifically, eIF3a promotes the transcriptional activation of β-catenin and mediates its nuclear accumulation to form a complex with T cell factor 4 (TCF4). However, eIF3a has no significant effect on protein stability and translation. Proteomics analysis revealed that the candidate transcription factor, Yin Yang 1 (YY1), mediates the activated effect of eIF3a on β-catenin. Overall, the findings of this study implied that eIF3a contributes to the maintenance of NSCLC stem cell-like characteristics through the Wnt/β-catenin pathway. eIF3a is a potential target for the treatment and prognosis of NSCLC.

PGC7 regulates H3K27 me3 modification by inhibiting the interaction of YY1 with PRC2

PGC7(Dppa3 or Stella) is a small inherently disordered protein that mainly expressed in oocytes and plays a vital role in the regulation of DNA methylation reprograming in imprinted loci through interacting with other proteins. Most of PGC7-deficient zygotes are blocked at 2-cell stage with an increased H3K27 me3 level in the nucleus. Our previous work has indicated that PGC7 interacts with yin-yang1 (YY1) which is essential for recruitment of EZH2-containing PRC2 to H3K27 me3 modification sites. Here we found that the presence of PGC7 weakened the interaction between YY1 and PRC2 without disrupting the assembly of core subunits of the PRC2 complex. Additionally, PGC7 promoted AKT to phosphorylate serine 21 of EZH2, resulting in inhibition of EZH2 activity and the dissociation of EZH2 from YY1, thereby decreasing H3K27 me3 level. In zygotes, the PGC7-deficient and AKT inhibitor MK2206 both promoted EZH2 to enter the pronuclei but without disturbing the subcellular localization of YY1, and caused an increase in the level of H3K27 me3 in the pronuclei, as well as inhibition of the expression of zygote-activating genes regulated by H3K27 me3 in 2-cell embryos. In summary, PGC7 could affect zygotic genome activation during early embryonic development by regulating the level of H3K27 me3 through regulation of PRC2 recruitment, EZH2 activity and subcellular localization.

USP8 mitigates cognitive dysfunction of mice with sepsis-associated encephalopathy

BACKGROUND

Sepsis-associated encephalopathy (SAE) is a serious complication of sepsis which results from neuroinflammation and could lead to cognitive dysfunction. Ubiquitin-specific peptidase 8 (USP8) is involved in cognitive dysfunction. This study investigated the mechanism by which USP8 plays a role in cognitive dysfunction of SAE mice.

METHODS

The SAE models were established by performing cecal ligation and puncture in the mice. Subsequently, a series of tests and procedures were conducted to assess the cognitive dysfunction and pathological impairment of mice, including the Morris water maze test, Y-maze test, open field test, tail suspension test, fear conditioning test, and haematoxylin-eosin staining. The levels of USP8 and Yin Yang 1 (YY1) in brain tissues of mice were detected. In order to determine the effects of USP8 or YY1 on cognitive function, SAE mice were injected with an adenovirus-packaged vector that had overexpressed levels of USP8 or YY1 short hairpin RNA. The binding of USP8 to YY1 and the ubiquitination level of YY1 were analyzed using immunoprecipitation and ubiquitination experiments. Lastly, chromatin immunoprecipitation was carried out to analyze enrichment of YY1 on the USP8 promoter.

RESULTS

In SAE models, USP8 and YY1 were downregulated and cognitive functions were impaired. USP8 overexpression upregulated YY1 and attenuated the brain histopathological damage and cognitive dysfunction in SAE mice. USP8 upregulated YY1 protein level through deubiquitination, while YY1 was enriched on the USP8 promoter and activated USP8 transcription. The effects of USP8 overexpression on SAE mice was reversed secondary to YY1 silencing.

CONCLUSION

USP8 upregulated YY1 protein level through deubiquitination and YY1 activated USP8 transcription, and USP8-YY1 feedback loop attenuated cognitive dysfunction in SAE mice, which could potentially serve as a novel theoretical foundation for the management of SAE.

SETD7 promotes metastasis of triple-negative breast cancer by YY1 lysine methylation

Breast cancer has gradually become the predominant cause for cancer-associated death in women. The metastatic dissemination and underlying mechanisms of triple-negative breast cancer (TNBC) are not sufficiently understood. (Su(var)3-9, enhancer of zeste, Trithorax) domain-containing protein 7 (SETD7) is vital for promoting the metastasis of TNBC, as demonstrated in this study. Clinical outcomes were significantly worse in primary metastatic TNBC with upregulated SETD7. Overexpression of SETD7 in vitro and in vivo promotes migration of TNBC cells. Two highly conserved lysine (K) residues K173 and K411 of Yin Yang 1 (YY1) are methylated by SETD7. Further, we found that SETD7-mediated K173 residue methylation protects YY1 from the ubiquitin-proteasome degradation. Mechanistically, it was found that the SETD7/YY1 axis regulates epithelial-mesenchymal transition (EMT) and tumor cell migration via the ERK/MAPK pathway in TNBC. The findings indicated that TNBC metastasis is driven by a novel pathway, which may be a promising target for advanced TNBC treatment.

The New Youngest Case of Grange Syndrome with a Novel Biallelic Pathogenic Variant in YY1AP1

Introduction

Grange syndrome (OMIM 602531) is characterized by a constellation of symptoms of hypertension, stenosis, or occlusion of different arteries (including the cerebral, renal, abdominal, and coronary vessels) with a variable occurrence of brachysyndactyly, bone fragility, and congenital heart defects. Learning disabilities were also reported in some cases. Biallelic pathogenic variants in YY1AP1 are associated with the syndrome. Only 14 individuals with this ultra-rare syndrome (12 of them were molecularly confirmed) have hitherto been reported in the literature.

Case Presentation

We herein describe a 11/2-year-old additional female case of Grange syndrome with hypertension, patent ductus arteriosus, and brachysyndactyly who was subsequently confirmed to carry a novel homozygous frameshift variant (c.2291del; p.Pro764Leufs*12) in the YY1AP1 gene through whole-exome sequencing.

Conclusion

This report extends the allelic spectrum in Grange syndrome and helps provide insight into the potential role of YY1AP1 in the regulation of cellular processes.

Depletion of enhancer zeste homolog 2 (EZH2) directs transcription factors associated with T cell differentiation through epigenetic regulation of Yin Yang 1(YY1) in combating non-small cell lung cancer (NSCLC)

Non-Small Cell Lung Cancer (NSCLC) is the leading cause of death in all countries alike. In the current study, we have found out that Histone H3Lys4trimethylation is abnormal on YY1 in CD4⁺T Helper (T_H) cells of NSCLC patients which is evident by Histone H3Lys27 trimethylation mediated via EZH2. We investigated the status of Yin Yang 1 (YY1) and the involvement of certain transcription factors that lead to tumorigenesis after depleting endogenous EZH2 in vitro by CRISPR/Cas9 in the CD4⁺T_H1-or-T_H2-polarized cells isolated initially as CD4⁺T_H0 cells from the PBMC of the control subjects and patients suffering from NSCLC. After depletion of endogenous EZH2, RT-qPCR based mRNA expression analysis showed that there was an increase in the expression of T_H1 specific genes and a decrease in the expression of T_H2 specific genes in NSCLC patients CD4⁺T_H cells. We can conclude that this group of NSCLC patients may have the tendency at least in vitro to elucidate adaptive/protective immunity through the depletion of endogenous EZH2 along with the reduction in the expression of YY1. Moreover, depletion of EZH2 not only suppressed the CD4⁺CD25⁺FOXP3⁺Regulatory T cells (Treg) but also it aided the generation of CD8⁺Cytotoxic T Lymphocytes (CTL) which were involved in killing of the NSCLC cells. Thus the transcription factors involved in EZH2 mediated T cell differentiation linked to malignancies offers us an appealing avenue of targeted therapeutic intervention for NSCLC.

The HDAC2/YY1/c-Myc signaling axis regulates lung cancer cell migration and proliferation

Lung cancer is among the most aggressive types of malignant tumors that contributes to cancer-associated deaths worldwide with a high occurrence and fatality rate. Histone deacetylase 2 (HDAC2), prevent the aberrant transcription of a number of genes that are primarily responsible for controlling the cell cycle, cell proliferation, and signaling pathways in numerous cancers. Previous studies reported the role of HDACs and YY1 in the growth and development of several cancers. Although, it is noteworthy that remarkable efforts have been taken for the treatment of lung cancer using molecularly targeted therapies and chemotherapeutic agents, but the outcome is still poor for this critically persistent cancer. Therefore, the aim of the present study is to identify an efficacious, novel therapeutic biomarkers for the successful diagnosis of lung cancer at the early stage of the disease and the molecular insights involved. In the present study, qPCR and western bot data revealed that the expression level of HDAC2 and YY1 were upregulated in the cell lines and tumor samples of lung cancer patients. Moreover, MTT, qPCR, western blot, cell cycle analysis, and migration assays showed that inhibition of HDAC2 reduced YY1 expression, similarly, depletion of YY1 using knockdown approach inhibited the proliferation, migration, invasion, and blockage of the cell cycle by suppressing c-Myc in lung cancer cell lines. In conclusion, the current study findings support the notion that HDAC2's anticancer role was attributed through YY1 regulation by targeting c-Myc and could act as potential novel candidate biomarker for the lung cancer diagnosis.

The regulatory effect of the YY1/miR‑HCC2/BAMBI axis on the stemness of liver cancer cells

Cancer stem cells serve key roles in liver cancer recurrence and metastasis. Therefore, the present study evaluated novel regulators of stem cell factor expression to identify novel therapeutic strategies that could target liver cancer stem cells. Deep sequencing was performed to identify novel microRNAs (miRNAs) that were specifically altered in liver cancer tissues. The expression levels of stem cell markers were investigated by reverse transcription‑quantitative PCR and western blotting. Sphere formation assays and flow cytometry were used to assess tumor sphere‑forming ability and evaluate the population of cluster of differentiation 90⁺ cells. Tumor xenograft analyses were used to evaluate tumorigenicity, metastasis and stemness in vivo. Bioinformatics analyses and enhanced green fluorescent protein reporter assays or luciferase reporter assays were performed to identify the direct targets of miR‑HCC2 and its upstream transcription factors. MiR‑HCC2 strongly promoted the cancer stem cell‑like properties of liver cancer cells in vitro; it also contributed to tumorigenicity, metastasis and stemness in vivo. Bone morphogenic protein and activin membrane‑bound inhibitor homolog, a direct target of miR‑HCC2, activated the Wnt/β‑catenin signaling pathway to promote stemness in liver cancer cells. The transcription factor YY1 bound to the promoter of miR‑HCC2 and activated its transcription. The present study demonstrated the importance of miR‑HCC2 in the induction of stemness in liver cancer, providing new insights into liver cancer metastasis and recurrence.

Aggressive versus indolent insulinomas: new clinicopathological insights

Insulinomas are rare functional pancreatic neuroendocrine tumors. While most insulinomas are indolent and cured after surgery, 10-15% of cases show aggressive or malignant tumor behavior and metastasize locally or to distant organs. Patients with metastatic insulinoma survive significantly shorter. Recognizing aggressive insulinomas can help to predict prognosis, guide therapy and determine follow-up intensity after surgery. This review offers a summary of the literature on the significant clinical, pathological, genetic and epigenetic differences between indolent and aggressive insulinomas. Aggressive insulinomas are characterized by rapid onset of symptoms, larger size, expression of ARX and alpha-1-antitrypsin and decreased or absent immunohistochemical expression of insulin, PDX1 and GLP-1R. Moreover, aggressive insulinomas often harbor ATRX or DAXX mutations, the alternative lengthening of telomeres phenotype and chromosomal instability. Tumor grade and MEN1 and YY1 mutations are less useful for predicting behavior. Aggressive insulinomas have similarities to normal alpha-cells and non-functional pancreatic neuroendocrine tumors, while indolent insulinomas remain closely related to normal beta-cells. In conclusion, indolent and aggressive insulinoma are different entities, and distinguishing these will have future clinical value in determining prognosis and treatment.

Long non‑coding RNA BLACAT2/miR‑378a‑3p/YY1 feedback loop promotes the proliferation, migration and invasion of uterine corpus endometrial carcinoma

Uterine corpus endometrial carcinoma (UCEC) is a common gynecological malignancy with high rates of mortality and morbidity. The expression of long non‑coding RNA bladder cancer‑associated transcript 2 (BLACAT2) has been previously found to be aberrantly upregulated in UCEC. However, the regulatory consequences of this in UCEC progression remain poorly understood. In the present study, human UCEC cell lines AN3CA and HEC‑1‑A were infected with lentiviruses to overexpress BLACAT2 (Lv‑BLACAT2) or knock down BLACAT2 using short hairpin RNA (Lv‑shBLACAT2). BLACAT2 overexpression was found to promote the G1/S transition of cell cycle progression and UCEC cell proliferation. In addition, BLACAT2 overexpression was observed to facilitate UCEC cell migration and invasion. By contrast, BLACAT2 knockdown resulted in inhibitory effects in UCEC cell physiology. BLACAT2 overexpression also contributed to the activation of the MEK/ERK pathway. Subsequently, BLACAT2 was demonstrated to bind to microRNA (miR)‑378a‑3p according to dual‑luciferase assays, where it appeared to function as a sponge of miR‑378a‑3p in 293T cells. miR‑378a‑3p overexpression was found to suppress UCEC cell proliferation, invasion, and ERK activation. Lentivirus‑mediated knockdown of its target, the transcription factor Yin Yang‑1 (YY1), was observed to reverse the oncogenic effects of BLACAT2 overexpression. Furthermore, YY1 was found to bind to the promoter of BLACAT2, suggesting that YY1 can regulate BLACAT2 expression. To conclude, results from the present study suggest that BLACAT2, miR‑378a‑3p and YY1 can form a feedback loop instead of an unidirectional axis, which can in turn regulate UCEC tumorigenesis through the MEK/ERK pathway. The present study furthered the understanding of UCEC tumorigenesis and may provide novel therapeutic targets for UCEC treatment.

YY1 lactylation in microglia promotes angiogenesis through transcription activation-mediated upregulation of FGF2

BACKGROUND

Ocular neovascularization is a leading cause of blindness. Retinal microglia have been implicated in hypoxia-induced angiogenesis and vasculopathy, but the underlying mechanisms are not entirely clear. Lactylation is a novel lactate-derived posttranslational modification that plays key roles in multiple cellular processes. Since hypoxia in ischemic retinopathy is a precipitating factor for retinal neovascularization, lactylation is very likely to be involved in this process. The present study aimed to explore the role of lactylation in retinal neovascularization and identify new therapeutic targets for retinal neovascular diseases.

RESULTS

Microglial depletion by the colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX3397 suppresses retinal neovascularization in oxygen-induced retinopathy. Hypoxia increased lactylation in microglia and accelerates FGF2 expression, promoting retinal neovascularization. We identify 77 sites of 67 proteins with increased lactylation in the context of increased lactate under hypoxia. Our results show that the nonhistone protein Yin Yang-1 (YY1), a transcription factor, is lactylated at lysine 183 (K183), which is regulated by p300. Hyperlactylated YY1 directly enhances FGF2 transcription and promotes angiogenesis. YY1 mutation at K183 eliminates these effects. Overexpression of p300 increases YY1 lactylation and enhances angiogenesis in vitro and administration of the p300 inhibitor A485 greatly suppresses vascularization in vivo and in vitro.

CONCLUSIONS

Our results suggest that YY1 lactylation in microglia plays an important role in retinal neovascularization by upregulating FGF2 expression. Targeting the lactate/p300/YY1 lactylation/FGF2 axis may provide new therapeutic targets for proliferative retinopathies.

Regulation of TREM2 expression by transcription factor YY1 and its protective effect against Alzheimer's Disease

TREM2 encoding the transmembrane receptor protein TREM2 is a risk gene of Alzheimer's disease (AD), and the impairment of TREM2 functions in microglia due to mutations in TREM2 may significantly increase the risk of AD by promoting AD pathologies. However, how the expression of TREM2 is regulated and the transcription factors required for TREM2 expression are largely unknown. By luciferase assay, DNA pull-down and in silico predictions, we identified ying-yang-1(YY1) as a binding protein of the minimal promoter of the TREM2 gene, and the binding was further confirmed by EMSA and DNA pull-down assay. shRNA-mediated YY1 silencing significantly reduced the activity of the TREM2 minimal promoter and TREM2 protein levels in the microglial cell line BV2 and the neuroblastoma Neuro2A. Furthermore, we found that the levels of TREM2 and YY1 were both downregulated in lipopolysaccharide (LPS)-treated BV2 cells and in the brain of AD model mice. These results demonstrated that YY1 plays a crucial role in regulation of TREM2 expression. Our study suggests that microglial YY1 could be targeted to maintain TREM2 expression for AD prevention and therapy.

Myocardial brain-derived neurotrophic factor regulates cardiac bioenergetics through the transcription factor Yin Yang 1

AIMS

Brain-derived neurotrophic factor (BDNF) is markedly decreased in heart failure patients. Both BDNF and its receptor, tropomyosin-related kinase receptor (TrkB), are expressed in cardiomyocytes; however, the role of myocardial BDNF signalling in cardiac pathophysiology is poorly understood. Here, we investigated the role of BDNF/TrkB signalling in cardiac stress response to exercise and pathological stress.

METHODS AND RESULTS

We found that myocardial BDNF expression was increased in mice with swimming exercise but decreased in a mouse heart failure model and human failing hearts. Cardiac-specific TrkB knockout (cTrkB KO) mice displayed a blunted adaptive cardiac response to exercise, with attenuated upregulation of transcription factor networks controlling mitochondrial biogenesis/metabolism, including peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α). In response to pathological stress (transaortic constriction, TAC), cTrkB KO mice showed an exacerbated heart failure progression. The downregulation of PGC-1α in cTrkB KO mice exposed to exercise or TAC resulted in decreased cardiac energetics. We further unravelled that BDNF induces PGC-1α upregulation and bioenergetics through a novel signalling pathway, the pleiotropic transcription factor Yin Yang 1.

CONCLUSION

Taken together, our findings suggest that myocardial BDNF plays a critical role in regulating cellular energetics in the cardiac stress response.

Hydrogen regulates mitochondrial quality to protect glial cells and alleviates sepsis-associated encephalopathy by Nrf2/YY1 complex promoting HO-1 expression

BACKGROUND

Sepsis-associated encephalopathy (SAE) is a complication of the central nervous system in patients with sepsis. Currently, no effective treatment for sepsis is available. Hydrogen plays a protective role in different diseases; however, the detailed mechanism of hydrogen-treated disease remains unclear. The purpose of this study was to investigate the effect of hydrogen on SAE in vitro and in vivo and the mechanism of hydrogen in mitochondrial dynamics and its function in astrocytes and microglia stimulated by lipopolysaccharides (LPSs).

METHODS

Animal models of SAE were generated by cecal ligation and puncture, and the SAE model was established by in vitro LPS stimulation. MTT, lactate dehydrogenase (LDH), reactive oxygen species (ROS), heme oxygenase-1 (HO-1) activity, mitochondrial membrane potential (MMP), and cell apoptosis assays were used to determine the effect of hydrogen on astrocytes and microglia stimulated by LPSs. The relationships between nuclear factor erythroid 2-related factor 2 (Nrf2), YY1, and HO-1 were examined by chromatin immunoprecipitation and co-immunoprecipitation. Mitochondrial homeostasis-related proteins in LPS-stimulated glial cells and brain tissues of SAE mice were detected by western blotting. The effects of hydrogen treatment in the SAE mouse model were investigated using Morris water maze and Y-maze analyses.

RESULTS

After performing experiments with different concentrations of LPSs in vitro, we selected 1000 ng/ml for subsequent experiments. Hydrogen attenuated the increase in ROS, LDH, and apoptosis and promoted decreases in cell activity and MMP, further promoting an increase in HO-1 expression induced by LPSs in astrocytes and microglia. Moreover, hydrogen further promoted the expression of Nrf2, HO-1, PGC-1α, TFAM, PARKIN, and PINK1, inhibited LPS-induced OPA1 and MFN2 expression in astrocytes and microglia, and downregulated the expression of DRP1 after LPS induction. Intriguingly, hydrogen treatment enhanced the binding between Nrf2 and YY1. However, silencing Nrf2 or YY1 abolished the protective effects of hydrogen on cell activity, LDH, ROS, and MMP; apoptosis; and regulation of Nrf2, HO-1, PGC-1α, TFAM, OPA1, DRP1, MFN2, PARKIN, and PINK1 in microglia. Finally, hydrogen treatment improved the results of behavioral detection, apoptosis, Nrf2, HO-1, PGC-1α, TFAM, OPA1, DRP1, MFN2, PARKIN, PINK1, and cytokines in SAE in vivo.

CONCLUSIONS

Hydrogen improved cell injury and mitochondrial quality, which were associated with HO-1 expression promoted by the Nrf2/YY1 complex in vitro. Thus, hydrogen treatment may represent a novel therapeutic method for treating SAE.

Skewed X-chromosome Inactivation in Women with Idiopathic Intellectual Disability is Indicative of Pathogenic Variants

Intellectual disability (ID) is an early onset impairment in cognitive functioning and adaptive behavior, affecting approximately 1% of the population worldwide. Extreme skewing of X-chromosome inactivation (XCI) can be associated with ID phenotypes caused by pathogenic variants in the X chromosome. We analyzed the XCI pattern in blood samples of 194 women with idiopathic ID, using the androgen receptor gene (AR) methylation assay. Among the 136 patients who were informative, 11 (8%) presented with extreme or total XCI skewing (≥ 90%), which was significantly higher than expected by chance. Whole-exome data obtained from these 11 patients revealed the presence of dominant pathogenic variants in eight of them, all sporadic cases, resulting in a molecular diagnostic rate of 73% (8/11 patients). All variants were mapped to ID-related genes with dominant phenotypes: four variants in the X-linked genes DDX3X (an XCI escape gene; two cases), WDR45, and PDHA1, and four variants in the autosomal genes KCNB1, CTNNB1, YY1, and ANKRD11. Three of the autosomal genes had no obvious correlation with the observed XCI skewing. However, YY1 is a known transcriptional repressor that acts in the binding of the XIST long noncoding RNA on the inactive X chromosome, providing a mechanistic link between the pathogenic variant and the detected skewed XCI in the carrier. These data confirm that extreme XCI skewing in females with ID is highly indicative of causative X-linked pathogenic variants, and point to the possibility of identifying causative variants in autosomal genes with a XCI role.

Identification of miR-192 target genes in porcine endometrial epithelial cells based on miRNA pull-down

INTRODUCTION

MicroRNAs (miRNAs)-a class of small endogenous non-coding RNAs-are widely involved in post-transcriptional gene regulation of numerous physiological processes. High-throughput sequencing revealed that the miR-192 expression level appeared to be significantly higher in the blood exosomes of sows at early gestation than that in non-pregnant sows. Furthermore, miR-192 was hypothesized to have a regulatory role in embryo implantation; however, the target genes involved in exerting the regulatory function of miR-192 required further elucidation.

METHODS

In the present study, potential target genes of miR-192 in porcine endometrial epithelial cells (PEECs) were identified through biotin-labeled miRNA pull-down; functional and pathway enrichment analysis was performed via gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment. Bioinformatic analyses were concurrently used to predict the potential target genes associated with sow embryo implantation. In addition, double luciferase reporter vectors, reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR), and Western blot were performed to verify the targeting and regulatory roles of the abovementioned target genes.

RESULTS

A total of 1688 differentially expressed mRNAs were identified via miRNA pull-down. Through RT-qPCR, the accuracy of the sequencing data was verified. In the bioinformatics analysis, potential target genes of miR-192 appeared to form a dense inter-regulatory network and regulated multiple signaling pathways, such as metabolic pathways and the PI3K-Akt, MAPKs, and mTOR signaling pathways, that are relevant to the mammalian embryo implantation process. In addition, CSK (C-terminal Src kinase) and YY1 (Yin-Yang-1) were predicted to be potential candidates, and we validated that miR-192 directly targets and suppresses the expression of the CSK and YY1 genes.

CONCLUSION

We screened 1688 potential target genes of miR-192 were screened, and CSK and YY1 were identified as miR-192 target genes. The outcomes of the present study provide novel insights into the regulatory mechanism of porcine embryo implantation and the identification of miRNA target genes.

SIRT1 is transcriptionally repressed by YY1 and suppresses ferroptosis in rheumatoid arthritis

BACKGROUND

Sirtuin 1 (SIRT1) is reported downregulated in rheumatoid arthritis (RA), and the protective effects of SIRT1 on tissue damage and organ failure may be related to cellular ferroptosis. However, the exact mechanism by which SIRT1 regulates RA remains unclear.

METHODS

Quantitative real-time PCR (qPCR) and western blot assays were performed to explore the expressions of SIRT1 and Yin Yang 1 (YY1). CCK-8 assay was used for cytoactive detection. The interaction between SIRT1 and YY1 was validated by dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP). DCFH-DA assay and iron assay were applied to detect the reactive oxygen species (ROS) and iron ion levels.

RESULTS

In the serum of RA patients, SIRT1 was downregulated, but YY1 was upregulated. In LPS-induced synoviocytes, SIRT1 could increase cell viability and decrease ROS and iron levels. Mechanistically, YY1 downregulated the expression of SIRT1 by inhibiting its transcription. YY1 overexpression partly revised the effects of SIRT1 on ferroptosis in synoviocytes.

CONCLUSION

SIRT1 is transcriptionally repressed by YY1 and inhibits the ferroptosis of synoviocytes induced by LPS, so as to relieve the pathological process of RA. Therefore, SIRT1 might be a new diagnosis and therapeutic target of RA.

Hsa_circ_0001925 promotes malignant progression in triple-negative breast cancer via miR-1299/YY1 axis

BACKGROUND

Circular RNAs (circRNAs) are related to the pathogenesis and progression of triple-negative breast cancer (TNBC). The aim of this study was to investigate the role and mechanism of hsa_circ_0001925 in TNBC progression.

METHODS

Hsa_circ_0001925, microRNA (miR)-1299 and Yin Yang 1 (YY1) levels were examined in TNBC via reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry, wound healing assay and tube formation assay were conducted to estimate the effects of hsa_circ_0001925 on malignant phenotypes of TNBC tumors. Several protein levels were measured with western blot. The regulatory relationship between miR-1299 and hsa_circ_0001925 or YY1 was validated using a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft assay was used to estimate the effect of hsa_circ_0001925 in TNBC in vivo.

RESULTS

Hsa_circ_0001925 and YY1 levels were upregulated, while miR-1299 abundance was downregulated in TNBC tissues and cells. Hsa_circ_0001925 silencing constrained cell proliferation, migration and angiogenesis whereas it promoted apoptosis in vitro, and hsa_circ_0001925 silencing significantly curbed xenograft tumor growth in vivo. Hsa_circ_0001925 acted as a miRNA sponge for miR-1299. Hsa_circ_0001925 decreased YY1 expression by sponging miR-1299. MiR-1299 downregulation alleviated the effects of hsa_circ_0001925 knockdown on BC progression. MiR-1299 interacted with the 3' untranslated region (3' UTR) of YY1, and YY1 overexpression partly reversed the effects of miR-1299 overexpression on BC progression.

CONCLUSION

Our findings showed that hsa_circ_0001925 mediated TNBC progression via regulating miR-1299/YY1 axis, providing a potential target for BC treatment.

Salt-like transcription factor 4 promotes laryngeal cancer progression through transcriptional activation of ubiquitin-specific protease 21 to stabilize Yin Yang 1

Laryngeal cancer (LC) is a rare and challenging clinical problem. Our aim was to investigate the mechanism of salt-like transcription factor 4 (SALL4) in LC. LC tissue and paracancerous tissue were collected. Relative mRNA or protein levels were measured by quantitative real-time polymerase chain reaction or Western blot. MTT, wound healing, and transwell assay were performed to evaluate cell proliferation, migration and invasion. The binding relationship between SALL4 and USP21 promoter was verified by dual-luciferase assay and ChIP. Co-IP and glutathione-S-transferase (GST)-pull down were performed to measure the protein interaction between USP21 and YY1. Additionally, YY1 ubiquitination level was analyzed. It was found that SALL4 mRNA and SALL4 protein levels were elevated in LC clinical tissues and various LC cells. Knockdown of SALL4 inhibited epithelial-mesenchymal transition (EMT) of LC cells. USP21 was transcriptionally activated by SALL4. Co-IP and GST-pull down confirmed USP21 interacted with YY1. USP21 protected YY1 from degradation through deubiquitination. Furthermore, overexpression of USP21 reversed the effect of knockdown of SALL4 on YY1 and EMT in LC cells. In general, SALL4 facilitated EMT of LC cells through modulating USP21/YY1 axis.

YY1 was indispensable for the alleviation of quercetin on diabetic nephropathy-associated tubulointerstitial inflammation

BACKGROUND

The emergence of tubulointerstitial inflammation (TI) could accelerate the development of tubulointerstitial fibrosis (TIF) of diabetic nephropathy (DN). Yin Yang 1 (YY1) was a new pro-inflammatory mediator and became the important target of DN-related TIF. Quercetin performed an effective role in anti-inflammation and was probable to bind to YY1. However, the role of YY1 in quercetin's anti-inflammatory effect on DN-related TIF was uncovered.

PURPOSE

To investigate the potential effect and mechanism of quercetin against DN-related TI.

STUDY DESIGN AND METHODS

The protein levels of YY1 were examined in the renal tubular epithelial cells (RTECs) of db/db mice and HG-cultured HK-2 cells. Molecular modeling studies and YY1 overexpression lentivirus vector were selected to further confirm the indispensable part of YY1 in quercetin's TI protection in vitro. Luciferase assay and chromatin immunoprecipitation (ChIP) assay were carried out to identify whether YY1 directly regulated IL-6/STAT3 signaling by binding to the IL-6 promoter in quercetin's TI protection in vitro. At last, the important role of YY1-mediated IL-6/STAT3 signaling in quercetin's TIF protection effect was further identified by using of YY1 overexpression lentivirus vector and IL-6 specific inhibitor tocilizumab.

RESULTS

Along with the alleviated tubulointerstitial injury by quercetin in the RTECs of db/db mice and HK-2 cells stimulated by HG, YY1-mediated IL-6/STAT-3 pathway involved in TI protection of quercetin in vivo and in vitro. Quercetin bound to YY1 and decreased its protein expression, and YY1 directly suppressed IL-6 transcription by bounding to its promoter, resulting in the alleviation of inflammation by inactivating of IL-6/STAT-3 pathway in vitro. YY1-mediated IL-6/STAT-3 pathway was also indispensable for the alleviation of quercetin on DN-associated TIF.

CONCLUSION

YY1 could not be absent from quercetin's anti-inflammatory effect on DN-associated TIF via alleviating IL-6/STAT-3 pathway mediated TI.