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Cell Death Discovery Jun 2024Despite the advances in the understanding of reproductive physiology, the mechanisms underlying ovarian aging are still not deciphered. Recent research found an...
Despite the advances in the understanding of reproductive physiology, the mechanisms underlying ovarian aging are still not deciphered. Recent research found an association between impaired ATM-mediated DNA double-strand break (DSB) repair mechanisms and oocyte aging. However, direct evidence connecting ATM-mediated pathway function decline and impaired oocyte quality is lacking. The objective of this study was to determine the role of ATM-mediated DNA DSB repair in the maintenance of oocyte quality in a mouse oocyte knockdown model. Gene interference, in vitro culture, parthenogenesis coupled with genotoxicity assay approaches, as well as molecular cytogenetic analyses based upon next-generation sequencing, were used to test the hypothesis that intact ATM function is critical in the maintenance of oocyte quality. We found that ATM knockdown impaired oocyte quality, resulting in poor embryo development. ATM knockdown significantly lowered or blocked the progression of meiosis in vitro, as well as retarding and reducing embryo cleavage after parthenogenesis. After ATM knockdown, all embryos were of poor quality, and none reached the blastocyst stage. ATM knockdown was also associated with an increased aneuploidy rate compared to controls. Finally, ATM knockdown increased the sensitivity of the oocytes to a genotoxic active metabolite of cyclophosphamide, with increased formation of DNA DSBs, reduced survival, and earlier apoptotic death compared to controls. These findings suggest a key role for ATM in maintaining oocyte quality and resistance to genotoxic stress, and that the previously observed age-induced decline in oocyte ATM function may be a prime factor contributing to oocyte aging.
PubMed: 38914566
DOI: 10.1038/s41420-024-02041-z -
Nature Communications Jun 2024The NuA3 complex is a major regulator of gene transcription and the cell cycle in yeast. Five core subunits are required for complex assembly and function, but it...
The NuA3 complex is a major regulator of gene transcription and the cell cycle in yeast. Five core subunits are required for complex assembly and function, but it remains unclear how these subunits interact to form the complex. Here, we report that the Taf14 subunit of the NuA3 complex binds to two other subunits of the complex, Yng1 and Sas3, and describe the molecular mechanism by which the extra-terminal domain of Taf14 recognizes the conserved motif present in Yng1 and Sas3. Structural, biochemical, and mutational analyses show that two motifs are sandwiched between the two extra-terminal domains of Taf14. The head-to-toe dimeric complex enhances the DNA binding activity of Taf14, and the formation of the hetero-dimer involving the motifs of Yng1 and Sas3 is driven by sequence complementarity. In vivo assays in yeast demonstrate that the interactions of Taf14 with both Sas3 and Yng1 are required for proper function of the NuA3 complex in gene transcription and DNA repair. Our findings suggest a potential basis for the assembly of three core subunits of the NuA3 complex, Taf14, Yng1 and Sas3.
Topics: Saccharomyces cerevisiae Proteins; Saccharomyces cerevisiae; Protein Binding; Transcription Factor TFIID; Protein Subunits; TATA-Binding Protein Associated Factors; Histone Acetyltransferases; Protein Multimerization; Models, Molecular; Transcription, Genetic; Amino Acid Sequence
PubMed: 38914563
DOI: 10.1038/s41467-024-49730-y -
JCI Insight Jun 2024Spermatogenesis requires precise posttranslational control in the endoplasmic reticulum (ER), but the mechanism remains largely unknown. The protein disulfide isomerase...
Spermatogenesis requires precise posttranslational control in the endoplasmic reticulum (ER), but the mechanism remains largely unknown. The protein disulfide isomerase (PDI) family is a group of thiol oxidoreductases responsible for catalyzing the disulfide bond formation of nascent proteins. In this study, we generated 14 strains of KO mice lacking the PDI family enzymes and found that only PDI deficiency caused spermatogenesis defects. Both inducible whole-body PDI-KO (UBC-Cre/Pdifl/fl) mice and premeiotic PDI-KO (Stra8-Cre/Pdifl/fl) mice experienced a significant decrease in germ cells, testicular atrophy, oligospermia, and complete male infertility. Stra8-Cre/Pdifl/fl spermatocytes had significantly upregulated ER stress-related proteins (GRP78 and XBP1) and apoptosis-related proteins (Cleaved caspase-3 and BAX), together with cell apoptosis. PDI deletion led to delayed DNA double-strand break repair and improper crossover at the pachytene spermatocytes. Quantitative mass spectrometry indicated that PDI deficiency downregulated vital proteins in spermatogenesis such as HSPA4L, SHCBP1L, and DDX4, consistent with the proteins' physical association with PDI in normal testes tissue. Furthermore, PDI served as a thiol oxidase for disulfide bond formation of SHCBP1L. Thus, PDI plays an essential role in protein quality control for spermatogenesis in mice.
Topics: Animals; Male; Spermatogenesis; Protein Disulfide-Isomerases; Mice; Mice, Knockout; Testis; Endoplasmic Reticulum Chaperone BiP; Infertility, Male; Apoptosis; Spermatocytes; Endoplasmic Reticulum Stress; Oligospermia
PubMed: 38912589
DOI: 10.1172/jci.insight.177743 -
Heliyon Jun 2024Gastrointestinal cancer poses a considerable global health risk, encompassing a heterogeneous spectrum of malignancies that afflict the gastrointestinal tract. It is...
BACKGROUND
Gastrointestinal cancer poses a considerable global health risk, encompassing a heterogeneous spectrum of malignancies that afflict the gastrointestinal tract. It is significant to develop efficacious therapeutic agents, as they are indispensable for both the treatment and prevention of this formidable disease.
METHODS
In this study, we synthesized a novel thiophene derivative, designated as compound 1312. An assessment was performed to investigate its anti-proliferative activity in several cancer cell lines (GES-1, EC9706, SGC7901, and HT-29). Furthermore, we performed molecular biology techniques to investigate the inhibitory impact of compound 1312 on gastrointestinal cell lines SGC-7901 and HT-29.
RESULTS
Our findings reveal that compound 1312 exhibits significant efficacy in suppressing colony formation of cancer cells. Notably, it triggers cell cycle arrest at the G2/M phase in gastrointestinal cell lines SGC7901 and HT-29. Compound 1312 was confirmed to exert inhibitory effects on cell migration and invasion in SGC7901. Additionally, the compound elicits apoptotic cell death through the activation of the DNA repair enzyme poly (ADP-ribose) polymerase (PARP) and the caspase signaling cascade. Furthermore, experiments revealed that compound 1312 effectively suppresses both the β-tubulin cytoskeletal network and the Wnt/β-catenin signaling pathway. These multifaceted anti-cancer activities highlight the potential of compound 1312 as a promising therapeutic agent for the treatment of gastrointestinal malignancies.
CONCLUSION
This study indicates the promising potential of compound 1312 as a prospective candidate agent for gastrointestinal cancer treatment. Further comprehensive investigations are needed to explore its therapeutic efficacy in greater detail.
PubMed: 38912446
DOI: 10.1016/j.heliyon.2024.e32241 -
Frontiers in Pharmacology 2024Maintaining the structural integrity of genomic chromosomal DNA is an essential role of cellular life and requires two important biological mechanisms: the DNA damage... (Review)
Review
Maintaining the structural integrity of genomic chromosomal DNA is an essential role of cellular life and requires two important biological mechanisms: the DNA damage response (DDR) mechanism and telomere protection mechanism at chromosome ends. Because abnormalities in telomeres and cellular DDR regulation are strongly associated with human aging and cancer, there is a reciprocal regulation of telomeres and cellular DDR. Moreover, several drug treatments for DDR are currently available. This paper reviews the progress in research on the interaction between telomeres and cellular DNA damage repair pathways. The research on the crosstalk between telomere damage and DDR is important for improving the efficacy of tumor treatment. However, further studies are required to confirm this hypothesis.
PubMed: 38910895
DOI: 10.3389/fphar.2024.1379166 -
Cureus May 2024A focal serous tubal intraepithelial lesion (STIL) is a rare lesion found on fallopian tubes that are characterized by atypical epithelial cells exhibiting morphological...
An Incidental Fallopian Tube Focal Serous Tubal Intraepithelial Lesion (STIL) Discovered on a Postoperative Pathology Report Following Hysterectomy and Salpingectomy: A Case Report.
A focal serous tubal intraepithelial lesion (STIL) is a rare lesion found on fallopian tubes that are characterized by atypical epithelial cells exhibiting morphological abnormalities with the accumulation of mutant p53 proteins. The p53 gene is a tumor suppressor gene, and when mutated gives rise to mutant p53 proteins that promote cancer cell growth and survival. We present a case of a 47-year-old gravida 2, para 2002 (G2P2) female who presented to the outpatient clinic with bilateral lower quadrant abdominal pain and back pain of four years' duration. The patient's history included endometriosis with lysis of adhesions and gynecological laparoscopy, leiomyomata, infertility, ovarian cyst, dysmenorrhea, two full term births, and Essure implants used for contraception; her family history included maternal grandfather with breast cancer. Multiple fibroids and endometriosis were confirmed on pelvic ultrasound (US) and magnetic resonance imaging (MRI). Due to worsening pain, the patient chose to have an elective hysterectomy and Essure implant removal with bilateral salpingectomy. The postoperative pathology report revealed a right fallopian tube with a STIL. Multiple genetic mutations are known to contribute to the development of STILs including p53 and the breast cancer gene (BRCA). There are two BRCA genes, BRCA1 and BRCA2, that have many functions including producing proteins that repair damaged DNA. When mutated, this allows cells to divide and change rapidly, leading to certain types of cancer. Given the patient's family history of breast cancer, the patient was tested for BRCA1 and BRCA2 for which the results were negative. However, even without having a BRCA mutation that is known to increase the risk of ovarian, fallopian tube, and peritoneal cancers, STILs continue to pose an increased risk of high-grade serous ovarian carcinoma (HGSOC). This case demonstrates the reasoning behind prophylactic salpingectomies alongside hysterectomies and the significance of the postoperative pathology report from gynecological procedures.
PubMed: 38910622
DOI: 10.7759/cureus.60992 -
Reproductive Toxicology (Elmsford, N.Y.) Jun 2024Previous retrospective cohort studies have found that, compared with oxygen tension in the uterus and fallopian tubes (2 %-8 %), exposure of pre-implantation embryos...
Previous retrospective cohort studies have found that, compared with oxygen tension in the uterus and fallopian tubes (2 %-8 %), exposure of pre-implantation embryos to atmospheric oxygen tension (AtmO, 20 %) during assisted reproductive technology(ART) can affect embryo quality, pregnancy outcomes and offspring health. However, current research on the effects and mechanisms of AtmO on the development of embryos and offspring is mainly limited to animal experiments. Human embryonic stem cells (hESCs) play a special and irreplaceable role in the study of early human embryonic development. In this study, we used hESCs as a model to elucidate the possible effects and mechanisms of AtmO exposure on human embryonic development. We found that exposure to AtmO can reduce cell viability, produce oxidative stress, increase DNA damage, initiate DNA repair, activate autophagy, and increase cell apoptosis. We also noticed that approximately 50 % of hESCs survived, adapted and proliferated through high expression of self-renewal and pluripotency regulatory factors, and affected embryoid body differentiation. These data indicate that hESCs experience oxidative stress, accumulation of DNA damage, and activate DNA damage response under the selective pressure of AtmO.Some hESCs undergo cell death, whereas other hESCs adapt and proliferate through increased expression of self-renewal genes. The current findings provide in vitro evidence that exposure to AtmO during the early preimplantation stage negatively affects hESCs.
PubMed: 38909692
DOI: 10.1016/j.reprotox.2024.108648 -
Nature Communications Jun 2024DNA double-strand breaks are repaired by multiple pathways, including non-homologous end-joining (NHEJ) and microhomology-mediated end-joining (MMEJ). The balance of...
DNA double-strand breaks are repaired by multiple pathways, including non-homologous end-joining (NHEJ) and microhomology-mediated end-joining (MMEJ). The balance of these pathways is dependent on the local chromatin context, but the underlying mechanisms are poorly understood. By combining knockout screening with a dual MMEJ:NHEJ reporter inserted in 19 different chromatin environments, we identified dozens of DNA repair proteins that modulate pathway balance dependent on the local chromatin state. Proteins that favor NHEJ mostly synergize with euchromatin, while proteins that favor MMEJ generally synergize with distinct types of heterochromatin. Examples of the former are BRCA2 and POLL, and of the latter the FANC complex and ATM. Moreover, in a diversity of human cancer types, loss of several of these proteins alters the distribution of pathway-specific mutations between heterochromatin and euchromatin. Together, these results uncover a complex network of proteins that regulate MMEJ:NHEJ balance in a chromatin context-dependent manner.
Topics: DNA Breaks, Double-Stranded; Humans; DNA End-Joining Repair; Chromatin; Heterochromatin; Euchromatin; BRCA2 Protein; Ataxia Telangiectasia Mutated Proteins; DNA Repair
PubMed: 38909016
DOI: 10.1038/s41467-024-49232-x -
Journal of Molecular Biology Jun 2024CTC1-STN1-TEN1 (CST) is a single-stranded DNA binding protein vital for telomere length maintenance with additional genome-wide roles in DNA replication and repair....
CTC1-STN1-TEN1 (CST) is a single-stranded DNA binding protein vital for telomere length maintenance with additional genome-wide roles in DNA replication and repair. While CST was previously shown to function in double-strand break repair and promote replication restart, it is currently unclear whether it has specialized roles in other DNA repair pathways. Proper and efficient repair of DNA is critical to protecting genome integrity. Telomeres and other G-rich regions are strongly predisposed to oxidative DNA damage in the form of 8-oxoguanines, which are typically repaired by the base-excision repair (BER) pathway. Moreover, recent studies suggest that CST functions in the repair of oxidative DNA lesions. Therefore, we tested whether CST interacts with and regulates BER protein activity. Here, we show that CST robustly stimulates proteins involved in BER, including OGG1, Pol β, APE1, and LIGI, on both telomeric and non-telomeric DNA substrates. Biochemical reconstitution of the pathway indicates that CST stimulates BER. Finally, knockout of STN1 or CTC1 leads to increased levels of 8-oxoguanine, suggesting defective BER in the absence of CST. Combined, our results define an undiscovered function of CST in BER, where it acts as a stimulatory factor to promote efficient genome-wide oxidative repair.
PubMed: 38908783
DOI: 10.1016/j.jmb.2024.168672 -
The Journal of Investigative Dermatology Jun 2024Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high mortality rate. MC polyomavirus (MCPyV) causes 80% of MCCs, encoding the viral oncogenes small T...
Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high mortality rate. MC polyomavirus (MCPyV) causes 80% of MCCs, encoding the viral oncogenes small T (sT) and truncated large T antigens (tLT). These proteins impair the Rb1-dependent G1/S checkpoint blockade and subvert the host cell epigenome to promote cancer. Whole proteome analysis and proximal interactomics identified a tLT-dependent deregulation of DNA damage response (DDR). Our investigation revealed a previously unreported interaction between tLT and the histone methyltransferase EHMT2, to our knowledge. T Antigens knockdown reduced DDR protein levels and increased levels of the DNA damage marker γH2Ax. EHMT2 normally promotes H3K9 methylation and DDR signaling. Given that inhibition of EHMT2 did not significantly change the MCC cells proteome, tLT-EHMT2 interaction could affect the DDR. With tLT, we report that EHMT2 gained DNA damage repair proximal interactors. EHMT2 inhibition rescued proliferation in MCC cells depleted for their T antigens, suggesting impaired DDR and/or lack of checkpoint efficiency. Combined tLT and EHMT2 inhibition led to altered DDR, evidenced by multiple signaling alterations. Here we show that tLT hijacks multiple components of the DNA damage machinery to enhance tolerance to DNA damage in MCC cells, which could explain the genetic stability of these cancers.
PubMed: 38908781
DOI: 10.1016/j.jid.2024.04.034