UXT is a novel regulatory factor of regulatory T cells associated with Foxp3

UXT at the crossroads of cell death, immunity and neurodegenerative diseases

The ubiquitous expressed transcript (UXT), a member of the prefoldin-like protein family, modulates regulated cell death (RCD) such as apoptosis and autophagy-mediated cell death through nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), P53, P62, and methylation, and is involved in the regulation of cell metabolism, thereby affecting tumor progression. UXT also maintains immune homeostasis and reduces proteotoxicity in neuro-degenerative diseases through selective autophagy and molecular chaperones. Herein, we review and further elucidate the mechanisms by which UXT affects the regulation of cell death, maintenance of immune homeostasis, and neurodegenerative diseases and discuss the possible UXT involvement in the regulation of ferroptosis and immunogenic cell death, and targeting it to improve cancer treatment outcomes by regulating cell death and immune surveillance.

HOXD9 transcriptionally induced UXT facilitate breast cancer progression via epigenetic modification of RND3

BACKGROUND

Ubiquitously expressed transcript (UXT) is a prefoldin-like protein. It was reported that UXT played vital role in several cancer types. However, functional role of UXT in breast cancer need further investigation.

METHODS

mRNA level or protein level of were determined by qRT-PCR or western blots. Proliferation of breast cancer cells was evaluated by CCK-8 assay and EdU assay. Migrative and invasive ability of cells were determined by wound healing assay and transwell assay. Transcriptional activation of UXT was determined by dual luciferase activity. The enrichment of H3K27me3 and EZH2 on the promoter of RND3 was evaluated by ChIP assay. The methylation of RND3 promoter was determined by MSP assay. In vivo function of UXT was evaluated by xenograft model.

RESULTS

Our results indicated that UXT was elevated in breast cancer and associated with poor prognosis. HOXD9 elevated expression of UXT via transcriptional activation. UXT knockdown impaired the proliferation, migration and invasion. Rescue experiments suggested that UXT promoted malignant phenotypes of breast cancer cells via epigenetically repressing RND3. Moreover, UXT promoted tumorigeneses and metastasis of breast cancer cell in vivo.

CONCLUSION

Inhibition of UXT impaired proliferation and metastasis of cancer cell via promoting RND3. Moreover, UXT epigenetically repressed the expression of RND3 via recruiting EZH2 in the promoter of RND3.

Ubiquitous expressed transcript promotes tumorigenesis by acting as a positive modulator of the polycomb repressive complex 2 in clear cell renal cell carcinoma

BACKGROUND

The ubiquitous expressed transcript (UXT) plays a key role in various tumors by regulating transcriptional activity of multiple transcription factors, including androgen receptor (AR). However, the role of UXT in clear cell renal cell carcinoma (ccRCC) is still unknown.

METHODS

Yeast two-hybrid screening, GST pull-down and co-immunoprecipitation assays were performed to detect the interacting protein of UXT. Chromatin immunoprecipitation (ChIP) was performed to investigate the levels of histone H3 lysine 27 trimethylation at the HOXA9 promoters. CCK-8 assays, colony formation assays and Transwell assays were performed to detect the proliferation, colony formation, migration and invasion of renal cancer cells. Quantitative PCR analysis was performed to detect the expressions of UXT in human ccRCC samples.

RESULTS

The enhancer of zeste homolog 2 (EZH2) is a novel UXT interacting protein and UXT interacts with EZH2 in the nucleus. In addition, UXT interacts with the polycomb repressive complex 2 (PRC2) through directly binding to EZH2 and suppressor of zeste 12 homolog (SUZ12), but not to embryonic ectoderm development (EED). Moreover, the UXT activates EZH2 histone methyltransferase activity by facilitating EZH2 binding with SUZ12. We further provided striking evidences that knockdown of UXT inhibits proliferation, colony formation, migration and invasion of renal cancer cells, in an EZH2-dependent manner. Importantly, the upregulation of UXT expression was observed in clinical ccRCC samples, and the high expression level of UXT was associated with advanced stage, distant metastasis and poor overall survival in patients with ccRCC.

CONCLUSION

The UXT is a novel regulator of the PRC2 and acts as a renal cancer oncogene that affects the progression and survival of ccRCC patients.

Meta-Analysis of Maternal and Fetal Transcriptomic Data Elucidates the Role of Adaptive and Innate Immunity in Preterm Birth

Preterm birth (PTB) is the leading cause of newborn deaths around the world. Spontaneous preterm birth (sPTB) accounts for two-thirds of all PTBs; however, there remains an unmet need of detecting and preventing sPTB. Although the dysregulation of the immune system has been implicated in various studies, small sizes and irreproducibility of results have limited identification of its role. Here, we present a cross-study meta-analysis to evaluate genome-wide differential gene expression signals in sPTB. A comprehensive search of the NIH genomic database for studies related to sPTB with maternal whole blood samples resulted in data from three separate studies consisting of 339 samples. After aggregating and normalizing these transcriptomic datasets and performing a meta-analysis, we identified 210 genes that were differentially expressed in sPTB relative to term birth. These genes were enriched in immune-related pathways, showing upregulation of innate immunity and downregulation of adaptive immunity in women who delivered preterm. An additional analysis found several of these differentially expressed at mid-gestation, suggesting their potential to be clinically relevant biomarkers. Furthermore, a complementary analysis identified 473 genes differentially expressed in preterm cord blood samples. However, these genes demonstrated downregulation of the innate immune system, a stark contrast to findings using maternal blood samples. These immune-related findings were further confirmed by cell deconvolution as well as upstream transcription and cytokine regulation analyses. Overall, this study identified a strong immune signature related to sPTB as well as several potential biomarkers that could be translated to clinical use.

The molecular basis of immune regulation in autoimmunity

Autoimmune diseases can be triggered and modulated by various molecular and cellular characteristics. The mechanisms of autoimmunity and the pathogenesis of autoimmune diseases have been investigated for several decades. It is well accepted that autoimmunity is caused by dysregulated/dysfunctional immune susceptible genes and environmental factors. There are multiple physiological mechanisms that regulate and control self-reactivity, but which can also lead to tolerance breakdown when in defect. The majority of autoreactive T or B cells are eliminated during the development of central tolerance by negative selection. Regulatory cells such as Tregs (regulatory T) and MSCs (mesenchymal stem cells), and molecules such as CTLA-4 (cytotoxic T-lymphocyte associated antigen 4) and IL (interleukin) 10 (IL-10), help to eliminate autoreactive cells that escaped to the periphery in order to prevent development of autoimmunity. Knowledge of the molecular basis of immune regulation is needed to further our understanding of the underlying mechanisms of loss of tolerance in autoimmune diseases and pave the way for the development of more effective, specific, and safer therapeutic interventions.

Efficient nucleic acid delivery to murine regulatory T cells by gold nanoparticle conjugates

Immune responses have to be tightly controlled to guarantee maintenance of immunological tolerance and efficient clearance of pathogens and tumorigenic cells without induction of unspecific side effects. CD4⁺ CD25⁺ regulatory T cells (Tregs) play an important role in these processes due to their immunosuppressive function. Genetic modification of Tregs would be helpful to understand which molecules and pathways are involved in their function, but currently available methods are limited by time, costs or efficacy. Here, we made use of biofunctionalized gold nanoparticles as non-viral carriers to transport genetic information into murine Tregs. Confocal microscopy and transmission electron microscopy revealed an efficient uptake of the bioconjugates by Tregs. Most importantly, coupling eGFP-siRNA to those particles resulted in a dose and time dependent reduction of up to 50% of eGFP expression in Tregs isolated from Foxp3eGFP reporter mice. Thus, gold particles represent a suitable carrier for efficient import of nucleic acids into murine CD4⁺ CD25⁺ Tregs, superior to electroporation.

The EZH1-SUZ12 complex positively regulates the transcription of NF-κB target genes through interaction with UXT

Unlike other members of the polycomb group protein family, EZH1 has been shown to positively associate with active transcription on a genome-wide scale. However, the underlying mechanism for this behavior still remains elusive. Here, we report that EZH1 physically interacts with UXT, a small chaperon-like transcription co-activator. UXT specifically interacts with EZH1 and SUZ12, but not EED. Similar to upon knockdown of UXT, knockdown of EZH1 or SUZ12 through RNA interference in the cell impairs the transcriptional activation of nuclear factor (NF)-κB target genes induced by TNFα. EZH1 deficiency also increases TNFα-induced cell death. Interestingly, chromatin immunoprecipitation and the following next-generation sequencing analysis show that H3K27 mono-, di- and tri-methylation on NF-κB target genes are not affected in EZH1- or UXT-deficient cells. EZH1 also does not affect the translocation of the p65 subunit of NF-κB (also known as RELA) from the cytosol to the nucleus. Instead, EZH1 and SUZ12 regulate the recruitment of p65 and RNA Pol II to target genes. Taken together, our study shows that EZH1 and SUZ12 act as positive regulators for NF-κB signaling and demonstrates that EZH1, SUZ12 and UXT work synergistically to regulate pathway activation in the nucleus.