Identification of proline-rich protein 11 as a major regulator in mouse spermatogonia maintenance via an increase in BMI1 protein stability

A single-nucleus transcriptomic atlas characterizes cell types and their molecular features in the ovary of adult Nile tilapia

In fish species, there is limited analysis of signature transcriptome profiles at the single-cell level in gonadal cells. Here, the molecular signatures of distinct ovarian cell categories in adult Nile tilapia (Oreochromis niloticus) were analysed using single-nucleus RNA sequencing (snRNA-seq). We identified four cell types (oogonia, oocytes, granulosa cell, and thecal cell) based on their specifically expressed genes and biological functions. Similarly, we found some key pathways involved in ovarian development that may affect germline-somatic interactions. A cell-to-cell communication network between the distinct cell types was constructed. We found that the bidirectional communication is mandatory for the development of germ cells and somatic cells in fish ovaries, and the granulosa cells and thecal cells play a central regulating role in the cell network in fish ovary. Additionally, we identified some novel candidate marker genes for various types of ovarian cells and also validated them using in situ hybridization. Our work reveals an ovarian atlas at the cellular and molecular levels and contributes to providing insights into oogenesis and gonad development in fish.

RNF26-mediated ubiquitination of TRIM21 promotes bladder cancer progression

RNF26 is an important E3 ubiquitin ligase that has been associated with poor prognosis in bladder cancer. However, the underlying mechanisms of RNF26 in bladder cancer tumorigenesis are not fully understood. In the present study, we found that RNF26 expression level was significantly upregulated in the bladder cancer tissues, and higher RNF26 expression is closely associated with poorer prognosis, lower immune cell infiltration, and more sensitive to immune checkpoint blockade drugs and chemotherapy drugs, including cisplatin, VEGFR-targeting drugs and MET-targeting drugs. RNF26 knockdown in UMUC3 and T24 cell lines inhibited cell growth, colony formation and migratory capacity. Meanwhile, RNF26 overexpression had the opposite effects. Mechanistically, RNF26 exerts its oncogenic function by binding to TRIM21 and promoting its ubiquitination and subsequent degradation. Moreover, we revealed ZHX3 as a downstream target of RNF26/TRIM21 pathway in bladder cancer. Taken together, we identified a novel RNF26/TRIM21/ZHX3 axis that promotes bladder cancer progression. Thus, the RNF26/TRIM21/ZHX3 axis constitutes a potential efficacy predictive marker and may serve as a therapeutic target for the treatment of bladder cancer.

ASB1 inhibits prostate cancer progression by destabilizing CHCHD3 via K48-linked ubiquitination

Prostate cancer is a major contributor to male mortality worldwide. In this study, we revealed that Ankyrin Repeat and SOCS Box Containing 1 (ASB1) expression was significantly decreased in prostate cancer tissues, correlating strongly with poor patient prognosis. Notably, the group with low ASB1 expression exhibited an increased proportion of M2 macrophages and showed resistance to immune checkpoint inhibitors and cisplatin, but remained sensitive to androgen-receptor-targeting drug bicalutamide. Silencing ASB1 enhanced prostate cancer cell proliferation, clonogenicity, and migration, whereas its overexpression exerted the opposite effects. Through quantitative mass spectrometry interactome analysis, we identified 37 novel proteins interacting with ASB1, including CHCHD3. Subsequent experiments including co-immunoprecipitation, cycloheximide treatment, and ubiquitination assays, revealed that ASB1 interacts with CHCHD3, promoting its degradation via K48-linked ubiquitination. Cell rescue experiments further demonstrated that ASB1 inhibits prostate cancer cell through the CHCHD3/reactive oxygen species (ROS) pathway. Taken together, our study indicated that ASB1 functions as a tumor suppressor by inhibiting CHCHD3/ROS signaling, thereby playing a vital part in prevention of prostate cancer proliferation, clonogenicity, and migration.

TRIM8 promotes ovarian cancer proliferation and migration by targeting VDAC2 for ubiquitination and degradation

BACKGROUND

Ovarian cancer is a common gynecological tumor with high malignant potential and poor prognosis. TRIM8, is involved in the development of various tumors, but its precise regulatory role in ovarian cancer is still unknown.

AIMS

The aim of this study was to explore the specific mechanism by which TRIM8 regulates ovarian cancer.

MATERIALS AND METHODS

We used bioinformatics analysis to screen for high expression of TRIM8 in ovarian cancer. The expression of TRIM8 in healthy and cancerous ovarian tissues was assessed by immunofluorescence. TRIM8 was silenced or overexpressed in ovarian cancer cell lines, with cell proliferation and migration evaluated by CCK8, transwell and clonal formation assays. The effect of TRIM8 on ovarian cancer cells in vivo was assessed by subcutaneous tumor formation experiments in nude mice. The potential interacting protein VDAC2 was identified by mass spectrometry. The mechanism underlying TRIM8 regulation of VDAC2 was evaluated by co-immunoprecipitation and western blotting.

RESULTS

TRIM8 was overexpressed in ovarian cancer. TRIM8 promoted the proliferation and migration of ovarian cancer cells in vitro and the growth of subcutaneous tumors in mice in vivo. TRIM8 interacted with VDAC2, weakened the stability of the protein, and promoted its polyubiquitination and subsequent degradation. Knockdown of VDAC2 increased the resistance of ovarian cancer cells to iron death, whereas overexpression of VDAC2 attenuated ovarian cancer progression induced by TRIM8 overexpression.

DISCUSSION

TRIM8 promotes ovarian cancer proliferation and migration by targeting VDAC2 for ubiquitination and degradation, these finding may provide new targets for the treatment of ovarian cancer.

CONCLUSION

TRIM8 degraded VDAC2 through the ubiquitination pathway, increased the resistance of ovarian cancer cells to iron death, and promoted the proliferation and migration of ovarian cancer.

JMJD3 regulate H3K27me3 modification via interacting directly with TET1 to affect spermatogonia self-renewal and proliferation

BACKGROUND

In epigenetic modification, histone modification and DNA methylation coordinate the regulation of spermatogonium. Not only can methylcytosine dioxygenase 1 (TET1) function as a DNA demethylase, converting 5-methylcytosine to 5-hydroxymethylcytosine, it can also form complexes with other proteins to regulate gene expression. H3K27me3, one of the common histone modifications, is involved in the regulation of stem cell maintenance and tumorigenesis by inhibiting gene transcription.

METHODS

we examined JMJD3 at both mRNA and protein levels and performed Chip-seq sequencing of H3K27me3 in TET1 overexpressing cells to search for target genes and signaling pathways of its action.

RESULTS

This study has found that JMJD3 plays a leading role in spermatogonia self-renewal and proliferation: at one extreme, the expression of the self-renewal gene GFRA1 and the proliferation-promoting gene PCNA was upregulated following the overexpression of JMJD3 in spermatogonia; at the other end of the spectrum, the expression of differentiation-promoting gene DAZL was down-regulated. Furthermore, the fact that TET1 and JMJD3 can form a protein complex to interact with H3K27me3 has also been fully proven. Then, through analyzing the sequencing results of CHIP-Seq, we found that TET1 targeted Pramel3 when it interacted with H3K27me3. Besides, TET1 overexpression not only reduced H3K27me3 deposition at Pramel3, but promoted its transcriptional activation as well, and the up-regulation of Pramel3 expression was verified in JMJD3-overexpressing spermatogonia.

CONCLUSION

In summary, our study identified a novel link between TET1 and H3K27me3 and established a Tet1-JMJD3-H3K27me3-Pramel3 axis to regulate spermatogonia self-renewal and proliferation. Judging from the evidence offered above, we can safely conclude that this study provides new ideas for further research regarding the mechanism of spermatogenesis and spermatogenesis disorders on an apparent spectrum.

Slc26a1 is not essential for spermatogenesis and male fertility in mice

Thousands of genes are expressed in the testis of mice. However, the details about their roles during spermatogenesis have not been well-clarified for most genes. The purpose of this study was to examine the effect of Slc26a1 deficiency on mouse spermatogenesis and male fertility. Slc26a1-knockout (KO) mice were generated using CRISPR/Cas9 technology on C57BL/6J background. We found no obvious differences between Slc26a1-KO and Slc26a1-WT mice in fertility tests, testicular weight, sperm concentrations, or morphology. Histological analysis found that Slc26a1-KO mouse testes had normal germ cell types and mature sperm. These findings indicated that Slc26a1 was dispensable for male fertility in mice. Our results may save time and resources by allowing other researchers to focus on genes that are more meaningful for fertility studies. We also found that mRNAs of two Slc26a family members (Slc26a5 and Slc26a11) were expressed on higher mean levels in Slc26a1-KO total mouse testes, compared to Slc26a1-WT mice. This effect was not found in mouse GC-1 and GC-2 germ cell lines with the Slc26a1 gene transiently knocked down. This result may indicate that a gene compensation phenomenon was present in the testes of Slc26a1-KO mice.

Long non-coding RNA NRSN2-AS1 promotes ovarian cancer progression through targeting PTK2/β-catenin pathway

As a common malignant tumor among women, ovarian cancer poses a serious threat to their health. This study demonstrates that long non-coding RNA NRSN2-AS1 is over-expressed in ovarian cancer tissues using patient sample and tissue microarrays. In addition, NRSN2-AS1 is shown to promote ovarian cancer cell proliferation and metastasis both in vitro and in vivo. Mechanistically, NRSN2-AS1 stabilizes protein tyrosine kinase 2 (PTK2) to activate the β-catenin pathway via repressing MG-53-mediated ubiquitinated degradation of PTK2, thereby facilitating ovarian cancer progression. Rescue experiments verify the function of the NRSN2-AS1/PTK2/β-catenin axis and the effects of MG53 on this axis in ovarian cancer cells. In conclusion, this study demonstrates the key role of the NRSN2-AS1/PTK2/β-catenin axis for the first time and explores its potential clinical applications in ovarian cancer.

BAG3 regulates bone marrow mesenchymal stem cell proliferation by targeting INTS7

Background

BAG3 is an essential regulator of cell survival and has been investigated in the context of heart disease and cancer. Our previous study used immunoprecipitation-liquid chromatography-tandem mass spectrometry to show that BAG3 might directly interact with INTS7 and regulate bone marrow mesenchymal stem cell (BMMSCs) proliferation. However, whether BAG3 bound INTS7 directly and how it regulated BMMSCs expansion was unclear.

Methods

BAG3 expression was detected by quantitative real-time PCR in BMMSCs after siRNA-mediated BAG3 knockdown. BMMSC proliferation was determined using the CCK-8 and colony formation assays. The transwell migration, flow cytometry and TUNEL assays were performed to measure BMMSC migration, cell cycle and apoptosis, respectively. Moreover, co-immunoprecipitation, protein half-life assay and western blotting analyses were used to determine the regulatory mechanism underlying the BAG3-mediated increase in BMMSC proliferation.

Results

The results showed that knocking down BAG3 in BMMSCs markedly decreased their proliferative activity, colony formation and migratory capacity, and induced cell apoptosis as well as cell cycle arrest. Meanwhile, overexpression of BAG3 had the opposite effect. Bioinformatics and BAG3-INTS7 co-immunoprecipitation analyses revealed that BAG3 directly interacted with INTS7. Moreover, the downregulation of BAG3 inhibited the expression of INTS7 and promoted its ubiquitination. We also observed that BAG3 knockdown increased the levels of reactive oxygen species and the extent of DNA damage in BMMSCs. Notably, the upregulation of INTS7 or the addition of an antioxidant scavenger could rescue the BMMSC phenotype induced by BAG3 downregulation.

Conclusions

BAG3 directly interacts with INTS7 and promotes BMMSC expansion by reducing oxidative stress.