Long-term outcomes of endoscopic resection for well-differentiated nonampullary duodenal neuroendocrine tumors.

BACKGROUND & AIMS: Nonampullary duodenal neuroendocrine tumors (NAD-NETs) are rare with limited evidence regarding endoscopic treatment. The study aimed to investigate the efficacy and safety of endoscopic resection of well-differentiated NAD-NETs and evaluate long-term outcomes, including local recurrence and metastasis. METHODS: A total of 78 patients with NAD-NETs who underwent endoscopic resection between January 2011 and August 2022 were included. The clinicopathologic characteristics and treatment outcomes were collected and analyzed. RESULTS: En bloc resection was achieved for 74 of the tumors (94.9%) and R0 resection was obtained in 68 of the tumors (87.2%). Univariate analysis identified tumors in the second part of the duodenum, tumor size ≥ 10 mm and muscularis propria invasion as risk factors for non-curative resection. Two patients with R1 resection (vertical margin involvement) and two patients with lymphovascular invasion underwent additional surgery. Four patients experienced adverse events (5.1%), including two cases of delayed bleeding and two cases of perforation, all successfully managed conservatively. During a median follow-up period of 62.6 months, recurrence and lymph node metastasis were only detected in one patient with R1 resection 3 months after the original procedure. CONCLUSION: Endoscopic resection is safe and effective and provides a favorable long-term outcome for patients with well-differentiated NAD-NETs without regional lymph node or distant metastasis.

A single-cell transcriptional landscape of immune cells shows disease-specific changes of T cell and macrophage populations in human achalasia.

Achalasia is a rare motility disorder of the esophagus caused by the gradual degeneration of myenteric neurons. Immune-mediated ganglionitis has been proposed to underlie the loss of myenteric neurons. Here, we measure the immune cell transcriptional profile of paired lower esophageal sphincter (LES) tissue and blood samples in achalasia and controls using single-cell RNA sequencing (scRNA-seq). In achalasia, we identify a pattern of expanded immune cells and a specific transcriptional phenotype, especially in LES tissue. We show C1QC+ macrophages and tissue-resident memory T cells (TRM), especially ZNF683+ CD8+ TRM and XCL1+ CD4+ TRM, are significantly expanded and localized surrounding the myenteric plexus in the LES tissue of achalasia. C1QC+ macrophages are transcriptionally similar to microglia of the central nervous system and have a neurodegenerative dysfunctional phenotype in achalasia. TRM also expresses transcripts of dysregulated immune responses in achalasia. Moreover, inflammation increases with disease progression since immune cells are more activated in type I compared with type II achalasia. Thus, we profile the immune cell transcriptional landscape and identify C1QC+ macrophages and TRM as disease-associated immune cell subsets in achalasia.

The role of type II esophageal microbiota in achalasia: Activation of macrophages and degeneration of myenteric neurons.

OBJECTIVE: The gut microbiota plays a critical role in the appropriate development and maintenance of the enteric nervous system (ENS). Esophageal achalasia (EA) is a rare motility disorder characterized by the selective degeneration of inhibitory neurons in the esophageal myenteric plexus. This study aimed to evaluate the composition of the esophageal microbiota in achalasia and explore the potential microbial mechanisms involved in its pathogenesis. DESIGN: The lower esophageal mucosal microbiota was analyzed in patients with achalasia and control participants using 16 S rRNA sequencing. The association between the esophageal microbiota and achalasia was validated by inducing esophageal dysbiosis in C57BL/10 J and C57BL/10ScNJ (TLR4KO) mice via chronic exposure to ampicillin sodium in their drinking water. RESULTS: The esophageal microbiota in EA patients had lower diversity and a predominance of Gram-negative bacteria (Type II microbiota) compared to that in the healthy controls. Additionally, the relative abundance of Rhodobacter decreased significantly in patients with achalasia, which correlated with an enrichment of lipopolysaccharide (LPS) biosynthesis based on the COG database. Antibiotic-treated mice showed an esophageal microbiota characterized by increased abundance of Gram-negative bacteria (Type II microbiome), decreased abundance of Rhodobacter, and enriched LPS biosynthesis. Compared to the control and TLR4KO mice, the antibiotic-treated wild-type mice had higher LES resting pressure, increased LES contraction rate after carbachol stimulation, and decreased relaxation response to L-arginine. Moreover, the number of myenteric neurons decreased, while the number of lamina propria macrophages (LpMs) increased after antibiotic exposure. Furthermore, the TLR4-MYD88-NF-κB pathway was up-regulated, and the production of TNF-α, IL-1ß, and IL-6 increased in the antibiotic-treated mice. CONCLUSIONS: Patients with achalasia exhibit esophageal dysbiosis, which may induce aberrant esophageal motility.

Endoscopic resection and suturing methods for non-ampullary duodenal submucosal tumors: "mini-invasive" treatments that should never be underestimated.

OBJECTIVE: To evaluate the effectiveness and safety of endoscopic resection and various suturing methods to treat non-ampullary duodenal submucosal tumors (NAD-SMTs). DESIGN: We performed a retrospective observational study of patients with NAD-SMTs who underwent endoscopic resection at Zhongshan Hospital, Fudan University, China, between June 2017 and December 2020. Data on patient characteristics, treatments and follow-up results were collected. The association between clinicopathologic characteristics and different suturing methods or adverse events were analyzed. RESULTS: Of 128 patients analyzed, 26 underwent endoscopic mucosal resection (EMR), 64 underwent endoscopic submucosal excavation (ESE), and 38 underwent endoscopic full-thickness resection (EFTR). EMR and ESR are both appropriate for non-full-thickness lesions, whereas ESE is more appropriate for tumors located in the bulb or descending duodenum. Gastric tube drainage is more strongly recommended after ESE. Satisfactory suturing is also vital endoscopic resection of NAD-SMTs. Metallic clips are often used in EMR or ESE of non-full-thickness lesions. The pathological findings revealed that the full-thickness lesions were predominantly gastrointestinal stromal tumors (GIST), Brunner's tumor or lipoma, and the surgeons usually used purse-string sutures to close the wounds. The operation time was longer for purse-string suture closure than metallic clip closure. Eleven patients had complications. Risk factors for adverse events included large-diameter tumor (≥ 2 cm), location in the descending part of the duodenum, involvement of the fourth layer of the duodenal wall, EFTR, and GIST. CONCLUSIONS: Endoscopic resection of NAD-SMTs is effective but is associated with a high incidence of complications due to their anatomical peculiarities. Preoperative diagnosis is quite important. Careful selection of treatment and suturing methods are necessary to reduce the risk of adverse effects. Given the increased frequency of severe complications during or following duodenal endoscopic resection, this procedure should be performed by experienced endoscopists.

Improving bowel preparation for colonoscopy with a smartphone application driven by artificial intelligence.

Optimal bowel preparation is a prerequisite for a successful colonoscopy; however, the rate of inadequate bowel preparation remains relatively high. In this study, we establish a smartphone app that assesses patient bowel preparation using an artificial intelligence (AI)-based prediction system trained on labeled photographs of feces in the toilet and evaluate its impact on bowel preparation quality in colonoscopy outpatients. We conduct a prospective, single-masked, multicenter randomized clinical trial, enrolling outpatients who own a smartphone and are scheduled for a colonoscopy. We screen 578 eligible patients and randomize 524 in a 1:1 ratio to the control or AI-driven app group for bowel preparation. The study endpoints are the percentage of patients with adequate bowel preparation and the total BBPS score, compliance with dietary restrictions and purgative instructions, polyp detection rate, and adenoma detection rate (secondary). The prediction system has an accuracy of 95.15%, a specificity of 97.25%, and an area under the curve of 0.98 in the test dataset. In the full analysis set (n = 500), adequate preparation is significantly higher in the AI-driven app group (88.54 vs. 65.59%; P < 0.001). The mean BBPS score is 6.74 ± 1.25 in the AI-driven app group and 5.97 ± 1.81 in the control group (P < 0.001). The rates of compliance with dietary restrictions (93.68 vs. 83.81%, P = 0.001) and purgative instructions (96.05 vs. 84.62%, P < 0.001) are significantly higher in the AI-driven app group, as is the rate of additional purgative intake (26.88 vs. 17.41%, P = 0.011). Thus, our AI-driven smartphone app significantly improves the quality of bowel preparation and patient compliance.

A cross-sectional study reveals a chronic low-grade inflammation in achalasia.

BACKGROUND AND AIM: Immune-mediated neuroinflammation has been proposed to underlie the loss of lower esophageal sphincter (LES) myenteric neurons in achalasia. However, the immune status and key pathogenic immune subpopulations remain unclear. This study aims to evaluate the inflammatory status of patients with achalasia and their correlation with clinical characteristics, and further explore the key pathogenic subpopulations. METHODS: We investigated the complete blood cell count and inflammatory markers in a large population of patients with achalasia (n = 341) and healthy controls (n = 80). The subpopulations of lymphocytes were analyzed by flow cytometry. Immunofluorescence was used to determine immune cell infiltration in the LES. Transcriptome changes of the key subpopulation were determined by RNA sequencing analysis. RESULTS: NLR, MLR, CRP, globulin, IL-6 and IL-10 were significantly elevated in patients with achalasia. MLR and globulin were positively correlated with disease duration. The absolute count and percentage of CD8+ T cells in peripheral blood and its infiltration around ganglion in the LES were significantly increased in achalasia. Transcriptome analysis indicated that CD8+ T cells were activated and proliferative. In addition to multiple inflammatory pathways, regulation of neuroinflammatory response pathway was also significantly up-regulated in achalasia. GSEA analysis revealed a close association with autoimmune diseases. CONCLUSIONS: Patients with achalasia suffered from chronic low-grade inflammation with dysregulated immune cells and mediators associated with disease duration. CD8+ T cells might be the key pathogenic subpopulation of achalasia. Our results provide an important immune cell signature of the pathogenesis of achalasia.

Poor intracytoplasmic sperm injection outcome in infertile males with azoospermia factor c microdeletions.

OBJECTIVE: To explore whether the presence of azoospermia factor c (AZFc) microdeletions adversely affects intracytoplasmic sperm injection (ICSI) outcome. DESIGN: Retrospective cohort. SETTING: University hospital. PATIENT(S): A total of 293 patients with azoospermia or severe oligozoospermia AZFc deletions underwent 345 ICSI cycles, and 363 idiopathic patients with normal Y chromosome underwent 462 ICSI cycles. INTERVENTION(S): Testicular sperm aspiration, microdissection testicular sperm extraction. MAIN OUTCOME MEASURE(S): The main clinical outcome parameters were cumulative clinical pregnancy rate, cumulative live birth delivery rate, and no embryo suitable for transfer cycle rate. RESULT(S): Compared with the control group, the AZFc deletion group exhibited poorer ICSI outcome, with significant differences between the 2 groups for cumulative clinical pregnancy rate (45.39% vs. 67.49%; odds ratio [OR], 2.843; 95% confidence interval [CI]), cumulative live birth delivery rate (35.15% vs. 53.44%; OR, 2.234; 95% CI), no embryo suitable for transfer cycle rate (15.07% vs. 8.23%; OR, 0.565; 95% CI), fertilization rate (46.80% vs. 53.37%; adjusted ß, -0.074; 95% CI), implantation rate (28.63% vs. 31.26%; adjusted ß, -0.075; 95% CI) separately. The poor ICSI outcome of the AZFc deletion group was related to AZFc microdeletions by linear and logistic regression analyses. CONCLUSION(S): AZFc microdeletions adversely affect ICSI outcome; patients with AZFc deletion should be informed that they have reduced opportunities to be biological fathers.

Controlled hypertension under hemostasis prevents post-gastric endoscopic submucosal dissection bleeding: a prospective randomized controlled trial.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a prominent minimally invasive operative technique for treating early gastrointestinal tumors but can result in postoperative bleeding. We conducted a randomized controlled trial to determine whether increasing blood pressure under hemostasis during gastric ESD to identify potential bleeding spots reduces the risk of post-ESD bleeding. METHODS: In this randomized, controlled, single-blinded clinical trial, 309 patients with early gastric cancer who were admitted to a hospital to undergo ESD were recruited from March 2017 to February 2018 and were randomized into intervention and control groups. In the control group, patients underwent normal ESD. In the intervention group, we increased patients' blood pressure to 150 mmHg for 5 min using a norepinephrine pump (0.05 µg/kg/min initial dose) after the specimen was extracted during the ESD operation to identify and coagulate potential bleeding spots with hot biopsy forceps. Our primary outcome was the incidence of postoperative bleeding over 60-day follow-up. RESULTS: The incidence of post-ESD bleeding was lower in the intervention group (1.3%, 2/151) than in the control group (10.1%, 16/158, p = 0.01). Deeper tumor invasion was associated with a higher risk of post-ESD bleeding (5.3% in mucosal/submucosal layer 1 group vs. 12.5% in submucosal layer 2/muscularis propria group, p < 0.001). Multi-factor but not univariate analysis showed that proton pump inhibitor administration three times per day may be a better choice than twice per day. CONCLUSION: Increasing blood pressure under hemostasis during ESD to identify and coagulate potential bleeding spots could reduce the risk of delayed bleeding after gastric ESD.

Endoscopic full-thickness resection (EFTR) without laparoscopic assistance for nonampullary duodenal subepithelial lesions: our clinical experience of 32 cases.

BACKGROUND: Standard treatment for nonampullary duodenal tumors has not yet been established. In case of tumors originated from the muscularis propria (MP) layer and adherent to the serosa layer, the lesions can not be completely removed by ESD. However, with the development of the endoscopic suture technique, endoscopic full-thickness resection (EFTR) of duodenal subepithelial lesions has become possible. METHODS: We retrospectively analyzed 32 patients with nonampullary duodenal subepithelial lesions who underwent EFTR between February 2012 and January 2017. The suturing method, complications that occurred during and after the operations, perioperative management, tumor characteristics, and pathological findings were analyzed in all patients. RESULTS: The complete resection rate was 100%; all patients successfully received EFTR except for one patient who required conversion to open surgery. Severe abdominal pain was observed after the operation in one patient who then received laparoscopic exploration, and the possibility of delayed perforation was considered. Another patient showed a decline in blood oxygen saturation (SO2) and was transferred to the intensive care unit (ICU) for further management. Delayed bleeding and fistula were not observed. All patients achieved complete remission. CONCLUSION: EFTR is a safe, minimally invasive treatment modality that ensures complete eradication of the duodenal subepithelial lesions.

Epigenetic dynamics and interplay during spermatogenesis and embryogenesis: implications for male fertility and offspring health.

Mapping epigenetic modifications and identifying their roles in the regulation of spermatogenesis and embryogenesis are essential for gaining fundamental medical understandings and for clinical applications. More and more evidence has shown that specific epigenetic modifications are established during spermatogenesis, which will be transferred into oocyte via fertilisation, and play an important role in the early embryo development. Defects in epigenetic patterns may increase the risk of abnormal spermatogenesis, fertilisation failure, early embryogenesis abnormality and several other complications during pregnancy. This review mainly discusses the relationship between altered epigenetic profiles and reproductive diseases, highlighting how epigenetic defects affect the quality of sperm and embryo.

Overexpression of gelsolin reduces the proliferation and invasion of colon carcinoma cells.

The enhanced motility of cancer cells via the remodeling of the actin cytoskeleton is crucial in the process of cancer cell invasion and metastasis. It was previously demonstrated that gelsolin (GSN) may be involved as a tumor or a metastasis suppressor, depending on the cell lines and model systems used. In the present study, the effect of GSN on the growth and invasion of human colon carcinoma (CC) cells was investigated using reverse transcription quantitative polymerase chain reaction and western blotting. It was observed that upregulation of the expression of GSN in human CC cells significantly reduced the invasiveness of these cells. The expression levels of GSN were observed to be reduced in CC cells, and the reduced expression level of GSN was often associated with a poorer metastasis­free survival rate in patients with CC (P=0.04). In addition, the overexpression of GSN inhibited the invasion of CC cells in vitro. Furthermore, GSN was observed to inhibit signal transducer and activator of transcription (STAT) 3 signaling in CC cells. Together, these results suggested that GSN is critical in regulating cytoskeletal events and inhibits the invasive and/or metastatic potential of CC cells. The results obtained in the present study may improve understanding of the functional and mechanistic links between GSN as a possible tumor suppressor and the STAT3 signaling pathway, with respect to the aggressive nature of CC. In addition, the present study demonstrated the importance of GSN in regulating the invasion and metastasis of CC cells at the molecular level, suggesting that GSN may be a potential predictor of prognosis and treatment success in CC.

Lower expression of ER-α36 is associated with the development of endometrial hyperplasia in PCOS patients.

OBJECTIVE: To explore the expression change of ER-α36 in endometria of PCOS patients. METHODS: Proliferative endometria were collected and divided into three groups: CE group (n=30), proliferative endometria from control women; PCOSE group (n=30), proliferative endometria from PCOS patients; HPCOSE group (n=15), hyperplastic endometria from PCOS patients. The cellular localization of ER-α36 and ER-α66 was analyzed by immunohistochemistry, and expression of ER-α36 and ER-α66 was determined by immunohistochemistry and Real-Time Quantitative PCR. The correlation between serum hormone concentration and expression of ER-α36 and ER-α66 was analyzed. RESULTS: ER-α36 was localized on the cell surface, cytoplasm and nucleus of glandular epithelial cells of both CE and PCOSE groups, mainly on the cell surface, and ER-α66 was localized on the nucleus. The protein and mRNA expression of ER-α36 was decreased from CE, PCOSE to HPCOSE group, while expression of ER-α66 showed no obvious difference among groups. The expression ratio of ER-α36 to ER-α66 of CE, PCOSE and HPCOSE group showed a decreasing tendency. The expression of ER-α36 and its expressive ratio to ER-α66 was negatively correlated with serum concentration of LH, LH/FSH, testosterone and androstenedione. CONCLUSIONS: Lower expression of ER-α66 is associated with the development of endometrial hyperplasia in PCOS patients.

ER-α36, a novel variant of estrogen receptor α, is involved in EGFR-related carcinogenesis in endometrial cancer.

OBJECTIVE: To explore the role of estrogen receptor-α36 (ER-α36) in epidermal growth factor receptor (EGFR)-related carcinogenesis in endometrial cancer. STUDY DESIGN: The expression of ER-α36, EGFR, and phospho-extracellular signal-regulated kinase was analyzed using immunohistochemistry in endometrial cancer samples. The cellular localization of ER-α36 and EGFR was determined using immunofluorescence in the endometrial cancer Hec1A cells. The level of phospho-extracellular signal-regulated kinase of Hec1A cells was determined using Western blotting after treatment with epidermal growth factor. RESULTS: Positive rate of ER-α36 was increased in high-stage (P = .03) and high-grade (P = .224) endometrial cancer; expression of ER-α36 and EGFR exhibited a significant positive correlation (r = 0.334, P = .025) and they showed substantial colocalization on the plasma membrane of glandular cells; phospho-extracellular signal-regulated kinase positive rate in ER-α36 positive group and EGFR positive group was higher than that of ER-α36 negative group (P = .014) and EGFR negative group (P = .016); finally, ER-α36 mediated epidermal growth factor-stimulated extracellular signal-regulated kinase activation in Hec1A cells. CONCLUSION: ER-α36 mediates EGFR-related extracellular signal-regulated kinase activation in endometrial cancer.

Borealin regulates bipolar spindle formation but may not act as chromosomal passenger during mouse oocyte meiosis.

In mitosis, Borealin is a member of the chromosomal passenger complex (CPC), which plays interaction roles with INCENP and survivin in the complex. Its roles in mammalian meiosis are unknown. Here, we report the expression, localization, and function of Borealin and its relation with survivin in mouse oocyte meiosis. Borealin expression was gradually increased from GV stage to MII. Immunofluorescence results revealed that Borealin accumulated near chromosomes after GVBD, localized at the spindle poles in MI, AI and MII, and at the midbody in TI stage. Taxol and nocodazole treatment showed that the localization of Borealin was dependent on microtubule dynamics, whereas survivin was independent of this. Disruption of Borealin function by antibody injection resulted in severe spindle assembly defects, but did not affect PBE. We also found that depletion of survivin by MO injection had no effect on the localization of Borealin. In conclusion, our data suggest that Borealin is required for bipolar spindle formation, but may not regulate spindle checkpoint activity as a component of the CPC during mouse oocyte meiosis.

PAK1 regulates spindle microtubule organization during oocyte meiotic maturation.

P21-activated kinase 1 (PAK1), an effector of Rho GTPase Rac 1 and Cdc42, is required for mitotic progression. However, its functions in meiosis are unclear. In the present study, we examined the expression, localization and function of PAK1 during mouse oocyte meiotic maturation and found that PAK1 was mainly associated with the meiotic spindle microtubules. Taxol treatment resulted in localization of PAK1 on spindle and aster microtubules, while nocodazole treatment induced the dispersion of PAK1 protein into the cytoplasm. Loss-of-function of PAK1 by both inhibitor treatment and morpholino oligonucleotide injection caused disorganized spindles, decreased polar body extrusion and misaligned chromosomes. In addition, inhibition of PAK1 resulted in abnormal localization of mitogen-activated protein kinase kinase (MEK). Taken together, our results suggest that PAK1 plays an important role in spindle assembly and chromosome alignment during mouse oocyte meiotic maturation.

Septin2 is modified by SUMOylation and required for chromosome congression in mouse oocytes.

In mitosis, centrosomes nucleate microtubules that capture the sister kinetochores of each chromosome to facilitate chromosome congression. In contrast, during meiosis chromosome congression on the acentrosomal spindle is driven primarily by movement of chromosomes along laterally associated microtubule bundles. Previous studies have indicated that septin2 is required for chromosome congression and cytokinesis in mitosis, we therefore asked whether perturbation of septin2 would impair chromosome congression and cytokinesis in meiosis. We have investigated its expression, localization and function during mouse oocyte meiotic maturation. Septin2 was modified by SUMO-1 and its levels remained constant from GVBD to metaphase II stages. Septin2 was localized along the entire spindle at metaphase and at the midbody in cytokinesis. Disruption of septins function with an inhibitor and siRNA caused failure of the metaphase I /anaphase I transition and chromosome misalignment but inhibition of septins after the metaphase I stage did not affect cytokinesis. BubR1, a core component of the spindle checkpoint, was labeled on misaligned chromosomes and on chromosomes aligned at the metaphase plate in inhibitor-treated oocytes that were arrested in prometaphase I/metaphase I, suggesting activation of the spindle assembly checkpoint. Taken together, our results demonstrate that septin2 plays an important role in chromosome congression and meiotic cell cycle progression but not cytokinesis in mouse oocytes.

ER-alpha36, a variant of ER-alpha, promotes tamoxifen agonist action in endometrial cancer cells via the MAPK/ERK and PI3K/Akt pathways.

BACKGROUND: Recently, a novel variant of ER-alpha, ER-alpha36 was identified and cloned. ER-alpha36 lacks intrinsic transcription activity and mainly mediates nongenomic estrogen signaling. Here, we studied the role of nongenomic estrogen signaling pathways mediated by ER-alpha36 in tamoxifen resistance and agonist action. METHODOLOGY: The cellular localization of ER-alpha36 was examined by immunofluorescence in MCF-7 cells and Hec1A cells. MCF-7 breast cancer cells, MCF-7 cells expressing recombinant ER-alpha36 (MCF-7/ER36), Hec1A endometrial cancer cells and Hec1A cells with siRNA knockdown of ER-alpha36 (Hec1A/RNAiER36) were treated with 17beta-estradial (E2) and tamoxifen (TAM) in the absence and presence of kinase inhibitor U0126 and LY294002. We examined phosphorylation of signaling molecules and the expression of c-Myc by immunoblotting, and tumor cell growth by MTT assay. CONCLUSIONS: ER variant ER-alpha36 enhances TAM agonist activity through activation of the membrane-initiated signaling pathways in endometrial cancer, and that ER-alpha36 is involved in de novo and acquired TAM resistance in breast cancer.

Perturbation of survivin expression affects chromosome alignment and spindle checkpoint in mouse oocyte meiotic maturation.

Survivin is a member of inhibitors of apoptosis proteins (IAPs), which have multiple regulatory functions in mitosis, but its roles in meiosis remain unknown. Here, we report its expression, localization and functions in mouse oocyte meiosis. Survivin displayed a maximal expression level in GV stage, and then gradually decreased from Pro-MI to MII stages. Immunofluorescent staining showed that survivin was restricted to the germinal vesicle, associated with centromeres from pro-metaphase I to metaphase I stages, distributed at the midzone and midbody of anaphase and telophase spindles, and located to centromeres at metaphase II stages. Depletion of survivin by antibody injection and morpholino injection resulted in severe chromosome misalignment, precocious polar body extrusion, and larger-than-normal polar bodies. Overexpression of survivin resulted in severe chromosome misalignment and prometaphase I or metaphase I arrest in a large proportion of oocytes. Our data suggest that survivin is required for chromosome alignment and that it may regulate spindle checkpoint activity during mouse oocyte meiosis.

Astrin regulates meiotic spindle organization, spindle pole tethering and cell cycle progression in mouse oocytes.

Astrin has been described as a microtubule and kinetochore protein required for the maintenance of sister chromatid cohesion and centrosome integrity in human mitosis. However, its role in mammalian oocyte meiosis is unclear. In this study, we find that Astrin is mainly associated with the meiotic spindle microtubules and concentrated on spindle poles at metaphase I and metaphase II stages. Taxol treatment and immunoprecipitation show that Astrin may interact with the centrosomal proteins Aurora-A or Plk1 to regulate microtubule organization and spindle pole integrity. Loss-of-function of Astrin by RNAi and overexpression of the coiled-coil domain results in spindle disorganization, chromosome misalignment and meiosis progression arrest. Thr24, Ser66 or Ser447 may be the potential phosphorylation sites of Astrin by Plk1, as site-directed mutation of these sites causes oocyte meiotic arrest at metaphase I with highly disordered spindles and disorganized chromosomes, although mutant Astrin localizes to the spindle apparatus. Taken together, these data strongly suggest that Astrin is critical for meiotic spindle assembly and maturation in mouse oocytes.