ING3 Is Essential for Asymmetric Cell Division during Mouse Oocyte Maturation.

ING3 (inhibitor of growth family, member 3) is a subunit of the nucleosome acetyltransferase of histone 4 (NuA4) complex, which activates gene expression. ING3, which contains a plant homeodomain (PHD) motif that can bind to trimethylated lysine 4 on histone H3 (H3K4me3), is ubiquitously expressed in mammalian tissues and governs transcriptional regulation, cell cycle control, and apoptosis via p53-mediated transcription or the Fas/caspase-8 pathway. Thus, ING3 plays a number of important roles in various somatic cells. However, the role(s) of ING3 in germ cells remains unknown. Here, we show that loss of ING3 function led to the failure of asymmetric cell division and cortical reorganization in the mouse oocyte. Immunostaining showed that in fully grown germinal vesicle (GV) oocytes, ING3 localized predominantly in the GV. After germinal vesicle breakdown (GVBD), ING3 homogeneously localized in the cytoplasm. In oocytes where Ing3 was targeted by siRNA microinjection, we observed symmetric cell division during mouse oocyte maturation. In those oocytes, oocyte polarization was not established due to the failure to form an actin cap or a cortical granule-free domain (CGFD), the lack of which inhibited spindle migration. These features were among the main causes of abnormal symmetric cell division. Interestingly, an analysis of the mRNA expression levels of genes related to asymmetric cell division revealed that only mTOR was downregulated, and, furthermore, that genes downstream of mTOR (e.g., Cdc42, Rac1, and RhoA) were also downregulated in siIng3-injected oocytes. Therefore, ING3 may regulate asymmetric cell division through the mTOR pathway during mouse oocyte maturation

Dietary therapy for patients with chronic pancreatitis in Japan: a cross-sectional online survey of physicians and registered dietitians

Background: This study was aimed towards understanding the current status of dietary therapy for patients with pancreatic exocrine insufficiency (PEI) in Japan and its alignment with Japanese recommendations for high-fat intake and concomitant high-potency pancreatic enzyme replacement therapy (PERT) by surveying treating physicians and registered dietitians. Methods: The 19-item physicians’ online questionnaire collected data about the number of patients with PEI treated, methods used to assess PEI and nutritional status in patients with PEI, as well as provision of dietary guidance and details of treatment with PERT. The 10-item registered dietitians’ online questionnaire captured data about the provision of dietary guidance, including setting (inpatient or outpatient) and details of nutritional guidance provided to patients. Results: Overall, 35 physicians and 23 dietitians completed the respective questionnaires. The primary cause of PEI in patients treated by physicians during the previous month was chronic pancreatitis (80.5%). Of 30 (86%) physicians who reported implementing dietary guidance for patients with PEI, less than half (43%) followed national guidelines and most (83%) implemented a low-fat diet. The use of PERT in recently treated patients with PEI was low. Amongst 11 (48%) dietitians who reported providing dietary guidance to patients with chronic pancreatitis and PEI, 7 (64%) recommended restricting fat intake in patients with uncompensated chronic pancreatitis. Dietitians overall were more likely to provide guidance about alcohol avoidance (91%) than smoking cessation (48%) to appropriate patients. Conclusion: This survey suggests that additional educational efforts are required to align the management practices of physicians and registered dietitians with evidence-based clinical practice guidelines for Japanese patients with chronic pancreatitis and PEI

Potential drug‐induced constipation: A retrospective study using a Japanese claims database

Abstract Background and Aim Detailed clinical information regarding drug‐induced constipation (DIC) is limited. This study aimed to investigate the real‐world situation of DIC. Methods This retrospective study used data from a Japanese claims database registered from 2014 to 2021. The constipation cohort included subjects with at least one record of treated constipation, while the non‐constipation cohort was selected through random stratified sampling method, to match the constipation cohort by gender. The study population and control with at least one history of a known causative drug (CD) were matched 1:1 using propensity scores. The proportion of potential DIC (pDIC), the timing of diagnosis for pDIC, and the proportion of prescriptions by drug class for both the CDs and the laxatives were calculated, while logistic regression analysis was performed to explore additional associated factors. Results Of the 4 533 905 subjects, 178 852 were eligible in both the study population and the control. The pDIC group comprised of 19 485 patients, which accounted for 10.9% of all treated constipation subjects, while the non‐constipation with CD group had 10 430 subjects. The median duration between the recorded CD prescription and treated constipation was 38.0 days. The most frequently prescribed CD was cardiovascular drugs (47.9%). All CD classes, being male, and some comorbidities were associated with the occurrence of pDIC. Conclusion The pDIC subjects accounted for about 11% of all treated constipation cases. Since DIC requires different treatment regimens compared to other constipation types, physicians should be cognizant to provide patients with optimized treatments

Histone methyltransferase Smyd3 regulates early embryonic lineage commitment in mice.

SET and MYND domain-containing protein 3 (Smyd3) is a histone H3 lysine 4 (H3K4) di- and tri-methyltransferase that forms a transcriptional complex with RNA polymerase II and activates the transcription of oncogenes and cell cycle genes in human cancer cells. However, the study of Smyd3 in mammalian early embryonic development has not yet been addressed. In the present study, we investigated the expression pattern of Smyd3 in mouse preimplantation embryos and the effects of RNA interference (RNAi)-mediated Smyd3 repression on the development of mouse embryos. We showed that Smyd3 mRNA levels increased after the two-cell stage, peaked at the four-cell stage, and gradually decreased thereafter. Moreover, in two-cell to eight-cell embryos, SMYD3 staining was more intense in the nuclei than it was in the cytoplasm. In Smyd3-knockdown embryos, the percentage of inner cell mass (ICM)-derived colony formation and trophectoderm (TE)-derived cell attachment were significantly decreased, which resulted in a reduction in the number of viable offspring. Furthermore, the expression of Oct4 and Cdx2 during mid-preimplantation gene activation was significantly decreased in Smyd3-knockdown embryos. In addition, the transcription levels of ICM and epiblast markers, such as Oct4, Nanog, and Sox2, the transcription levels of primitive endoderm markers, such as Gata6, and the transcription levels of TE markers, such as Cdx2 and Eomes, were significantly decreased in Smyd3-knockdown blastocysts. These findings indicate that SMYD3 plays an important role in early embryonic lineage commitment and peri-implantation development through the activation of lineage-specific genes

CHD1 acts via the Hmgpi pathway to regulate mouse early embryogenesis

The protein CHD1 is a member of the family of ATPase-dependent chromatin remodeling factors. CHD1, which recognizes trimethylated histone H3 lysine 4, has been implicated in transcriptional activation in organisms ranging from yeast to humans. It is required for pre-mRNA maturation, maintenance of mouse embryonic stem cell pluripotency and rapid growth of the mouse epiblast. However, the function(s) of CHD1 in mouse preimplantation embryos has not yet been examined. Here, we show that loss of CHD1 function led to embryonic lethality after implantation. In mouse embryos in which Chd1 was targeted by siRNA microinjection, the expression of the key regulators of cell fate specification Pou5f1 (also known as Oct4), Nanog and Cdx2 was dramatically decreased, starting at mid-preimplantation gene activation (MGA). Moreover, expression of Hmgpi and Klf5, which regulate Pou5f1, Nanog and Cdx2, was also significantly suppressed at zygotic gene activation (ZGA). Suppression of Hmgpi expression in Chd1-knockdown embryos continued until the blastocyst stage, whereas suppression of Klf5 expression was relieved by the morula stage. Next, we rescued HMGPI expression via Hmgpi mRNA microinjection in Chd1-knockdown embryos. Consequently, Pou5f1, Nanog and Cdx2 expression was restored at MGA and live offspring were recovered. These findings indicate that CHD1 plays important roles in mouse early embryogenesis via activation of Hmgpi at ZGA

Histone methyltransferase Smyd3 regulates early embryonic lineage commitment in mice.

SET and MYND domain-containing protein 3 (Smyd3) is a histone H3 lysine 4 (H3K4) di- and tri-methyltransferase that forms a transcriptional complex with RNA polymerase II and activates the transcription of oncogenes and cell cycle genes in human cancer cells. However, the study of Smyd3 in mammalian early embryonic development has not yet been addressed. In the present study, we investigated the expression pattern of Smyd3 in mouse preimplantation embryos and the effects of RNA interference (RNAi)-mediated Smyd3 repression on the development of mouse embryos. We showed that Smyd3 mRNA levels increased after the two-cell stage, peaked at the four-cell stage, and gradually decreased thereafter. Moreover, in two-cell to eight-cell embryos, SMYD3 staining was more intense in the nuclei than it was in the cytoplasm. In Smyd3-knockdown embryos, the percentage of inner cell mass (ICM)-derived colony formation and trophectoderm (TE)-derived cell attachment were significantly decreased, which resulted in a reduction in the number of viable offspring. Furthermore, the expression of Oct4 and Cdx2 during mid-preimplantation gene activation was significantly decreased in Smyd3-knockdown embryos. In addition, the transcription levels of ICM and epiblast markers, such as Oct4, Nanog, and Sox2, the transcription levels of primitive endoderm markers, such as Gata6, and the transcription levels of TE markers, such as Cdx2 and Eomes, were significantly decreased in Smyd3-knockdown blastocysts. These findings indicate that SMYD3 plays an important role in early embryonic lineage commitment and peri-implantation development through the activation of lineage-specific genes