Oocyte meiosis-coupled poly(A) polymerase α phosphorylation and activation trigger maternal mRNA translation in mice.

Mammalian oocyte maturation is driven by strictly regulated polyadenylation and translational activation of maternal mRNA stored in the cytoplasm. However, the poly(A) polymerase (PAP) that directly mediates cytoplasmic polyadenylation in mammalian oocytes has not been determined. In this study, we identified PAPα as the elusive enzyme that catalyzes cytoplasmic mRNA polyadenylation implicated in mouse oocyte maturation. PAPα was mainly localized in the germinal vesicle (GV) of fully grown oocytes but was distributed to the ooplasm after GV breakdown. Inhibition of PAPα activity impaired cytoplasmic polyadenylation and translation of maternal transcripts, thus blocking meiotic cell cycle progression. Once an oocyte resumes meiosis, activated CDK1 and ERK1/2 cooperatively mediate the phosphorylation of three serine residues of PAPα, 537, 545 and 558, thereby leading to increased activity. This mechanism is responsible for translational activation of transcripts lacking cytoplasmic polyadenylation elements in their 3'-untranslated region (3'-UTR). In turn, activated PAPα stimulated polyadenylation and translation of the mRNA encoding its own (Papola) through a positive feedback circuit. ERK1/2 promoted Papola mRNA translation in a 3'-UTR polyadenylation signal-dependent manner. Through these mechanisms, PAPα activity and levels were significantly amplified, improving the levels of global mRNA polyadenylation and translation, thus, benefiting meiotic cell cycle progression.

CNOT6L couples the selective degradation of maternal transcripts to meiotic cell cycle progression in mouse oocyte.

Meiotic resumption-coupled degradation of maternal transcripts occurs during oocyte maturation in the absence of mRNA transcription. The CCR4-NOT complex has been identified as the main eukaryotic mRNA deadenylase. In vivo functional and mechanistic information regarding its multiple subunits remains insufficient. Cnot6l, one of four genes encoding CCR4-NOT catalytic subunits, is preferentially expressed in mouse oocytes. Genetic deletion of Cnot6l impaired deadenylation and degradation of a subset of maternal mRNAs during oocyte maturation. Overtranslation of these undegraded mRNAs caused microtubule-chromosome organization defects, which led to activation of spindle assembly checkpoint and meiotic cell cycle arrest at prometaphase. Consequently, Cnot6l-/- female mice were severely subfertile. The function of CNOT6L in maturing oocytes is mediated by RNA-binding protein ZFP36L2, not maternal-to-zygotic transition licensing factor BTG4, which interacts with catalytic subunits CNOT7 and CNOT8 of CCR4-NOT Thus, recruitment of different adaptors by different catalytic subunits ensures stage-specific degradation of maternal mRNAs by CCR4-NOT This study provides the first direct genetic evidence that CCR4-NOT-dependent and particularly CNOT6L-dependent decay of selective maternal mRNAs is a prerequisite for meiotic maturation of oocytes.

[Critical quality attribute characterization of big brand TCM: taste formulation optimization strategy and application of Xiaoer Ganmao Oral Liquid based on taste quality attribute].

The taste is the quality attribute for the development and production of traditional Chinese medicine(TCM). To improve the medication compliance of the big brand TCM, Xiaoer Ganmao Oral Liquid, a correlation model between the electronic tongue sensor signal value and human sensory evaluation score was established, and an optimization strategy of taste improvement for Xiaoer Ganmao Oral Liquid was developed with the key techniques of statistical experimental design. Based on the above model, the optimal formulation was determined as follows: aspartame content of 1-2 mg·mL~(-1), acesulfame-K content of 1.5-3 mg·mL~(-1), and steviol glycoside content of 1-2 mg·mL~(-1). Furthermore, the optimal formulation was verified by human sensory evaluation. Therefore, the taste of Xiaoer Ganmao Oral Liquid was improved. Taking Xiaoer Ganmao Oral Liquid as an example, the present study developed the taste formulation optimization method based on the correlation between the electronic tongue and human sensory evaluation, which is expected to provide an important reference to improve the taste of oral liquid of TCM.

CFP1-dependent histone H3K4 trimethylation in murine oocytes facilitates ovarian follicle recruitment and ovulation in a cell-nonautonomous manner.

CxxC-finger protein 1 (CFP1)-mediated trimethylated histone H3 at lysine-4 (H3K4me3) during oocyte development enables the oocyte genome to establish the competence to generate a new organism. Nevertheless, it remains unclear to which extent this epigenetic modification forms an instructive component of ovarian follicle development. We investigated the ovarian functions using an oocyte-specific Cxxc1 knockout mouse model, in which the H3K4me3 accumulation is downregulated in oocytes of developing follicles. CFP1-dependent H3K4 trimethylation in oocytes was necessary to maintain the expression of key paracrine factors and to facilitate the communication between an oocyte and the surrounding granulosa cells. The distinct gene expression patterns in cumulus cells within preovulatory follicles were disrupted by the Cxxc1 deletion in oocytes. Both follicle growth and ovulation were compromised after CFP1 deletion, because Cxxc1 deletion in oocytes indirectly impaired essential signaling pathways in granulosa cells that mediate the functions of follicle-stimulating hormone and luteinizing hormone. Therefore, CFP1-regulated epigenetic modification of the oocyte genome influences the responses of ovarian follicles to gonadotropin in a cell-nonautonomous manner.

A combinatorial code for mRNA 3'-UTR-mediated translational control in the mouse oocyte.

Meiotic maturation of mammalian oocytes depends on the temporally and spatially regulated cytoplasmic polyadenylation and translational activation of maternal mRNAs. Cytoplasmic polyadenylation is controlled by cis-elements in the 3'-UTRs of mRNAs including the polyadenylation signal (PAS), which is bound by the cleavage and polyadenylation specificity factor (CPSF) and the cytoplasmic polyadenylation element (CPE), which recruits CPE binding proteins. Using the 3'-UTRs of mouse Cpeb1, Btg4 and Cnot6l mRNAs, we deciphered the combinatorial code that controls developmental stage-specific translation during meiotic maturation: (i) translation of a maternal transcript at the germinal vesicle (GV) stage requires one or more PASs that locate far away from CPEs; (ii) PASs distal and proximal to the 3'-end of the transcripts are equally effective in mediating translation at the GV stage, as long as they are not close to the CPEs; (iii) Both translational repression at the GV stage and activation after germinal vesicle breakdown require at least one CPE adjacent to the PAS; (iv) The numbers and positions of CPEs in relation to PASs within the 3'-UTR of a given transcript determines its repression efficiency in GV oocytes. This study reveals a previously unrecognized non-canonical mechanism by which the proximal PASs mediate 3'-terminal polyadenylation and translation of maternal transcripts.

A MAPK cascade couples maternal mRNA translation and degradation to meiotic cell cycle progression in mouse oocytes.

Mammalian oocyte maturation depends on the translational activation of stored maternal mRNAs upon meiotic resumption. Cytoplasmic polyadenylation element binding protein 1 (CPEB1) is a key oocyte factor that regulates maternal mRNA translation. However, the signal that triggers CPEB1 activation at the onset of mammalian oocyte maturation is not known. We provide evidence that a mitogen-activated protein kinase (MAPK) cascade couples maternal mRNA translation to meiotic cell cycle progression in mouse oocytes by triggering CPEB1 phosphorylation and degradation. Mutations of the phosphorylation sites or ubiquitin E3 ligase binding sites in CPEB1 have a dominant-negative effect in oocytes, and mimic the phenotype of ERK1/2 knockout, by impairing spindle assembly and mRNA translation. Overexpression of the CPEB1 downstream translation activator DAZL in ERK1/2-deficient oocytes partially rescued the meiotic defects, indicating that ERK1/2 is essential for spindle assembly, metaphase II arrest and maternal-zygotic transition (MZT) primarily by triggering the translation of key maternal mRNAs. Taken together, ERK1/2-mediated CPEB1 phosphorylation/degradation is a major mechanism of maternal mRNA translational activation, and is crucial for mouse oocyte maturation and MZT.

[Function and molecular mechanism of mitogen-activated protein kinase (MAPK) in regulating oocyte meiotic maturation and ovulation].

The mitogen-activated protein kinase (MAPK) signaling pathway is a highly conserved signal transduction pathway from yeast to human species, and is widely distributed in various eukaryotic cells. In almost all of the species studied over the past three decades, this signaling pathway plays a crucial role in the development of female germ cells and meiotic maturation. Especially in a variety of mammalian species including primates, rodents, and domestic animals, the MAPK signaling pathway is activated during the resumption of first oocyte meiosis and plays an indispensable role in meiotic spindle assembly and cell cycle progression. In granulosa cells of fully grown ovarian follicles, the MAPK pathway also mediates the physiological action of gonadotropins, including cumulus expansion, ovulation, and corpus luteum formation. Although the MAPK signaling pathway plays a wide range of physiological functions during the female reproduction process, and these functions are highly conserved in evolution, their underlying mechanisms, especially their direct and physiological target molecules, have not been sufficiently studied for a long time. In recent years, based on some new gene-editing mouse models and theoretical findings, as well as the wide application of various omics techniques, it has been further revealed that MAPK directly phosphorylates and activates the RNA binding protein cytoplasmic polyadenylation element-binding protein-1 (CPEB1), promoting poly(A) tail extension of maternal mRNA to regulate protein translation during meiotic recovery. These findings not only constitute the current basic mechanism of mammalian oocyte maturation and ovulation, but also provide useful research ideas for other related research in this field. In this review, we summarize the research findings in our laboratory and from other groups regarding the role of MAPK cascade in regulating oocyte maturation and ovulation. We also discuss the latest research progress on MAPK regulation of mRNA translation and degradation by directly activating the translation initiation complex and mRNA poly(A) polymerase by phosphorylation in the granulosa cells.

[In vitro anticoagulant activity of different processed products of Whitmania pigra by water extraction and bionic extraction].

In order to determine the scientificalness of traditionally processed Whitmania pigra, water extraction method and bionic extraction method were used respectively to extract the anticoagulating active components in W. pigra hanging dry products, talcum powder fried products and wine immersing-baked products. Activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and antithrombin activity were selected as the activity indexes to evaluate the anticoagulant activities of different processed W. pigra. Then the contents of protein in different processed W. pigra were measured by Coomassie brilliant blue method to preliminarily explain the reason of anticoagulant activity changes. When water extraction method was used, the results of APTT, PT, TT and antithrombin activity showed that the anticoagulant activities of W. pigra were decreased both in talcum powder fried products and wine immersing-baked products, and the activity order was as follows: hanging dried products> wine immersing-baked products>talcum powder fried products. This order was same as the protein content order. While when bionic extraction was used, APTT was shortened in talcum powder fried products, but all the other results indicated the anticoagulant activities of W. pigra processed products were increased, and the activity order was as follows: wine immersing-baked products>talcum powder fried products>hanging dry products. As compared with water extraction, the bionic extraction was more similar to the absorption process of W. pigra in human digestive system after oral administration and was more scientific. Therefore, the traditional processing method can not only modify the taste and smell, but also enhance the anticoagulant activity of W. pigra.

[Real-time detection of quality of Chinese materia medica: strategy of NIR model evaluation].

The definition of critical quality attributes of Chinese materia medica ( CMM) was put forward based on the top-level design concept. Nowadays, coupled with the development of rapid analytical science, rapid assessment of critical quality attributes of CMM was firstly carried out, which was the secondary discipline branch of CMM. Taking near infrared (NIR) spectroscopy as an example, which is a rapid analytical technology in pharmaceutical process over the past decade, systematic review is the chemometric parameters in NIR model evaluation. According to the characteristics of complexity of CMM and trace components analysis, a multi-source information fusion strategy of NIR model was developed for assessment of critical quality attributes of CMM. The strategy has provided guideline for NIR reliable analysis in critical quality attributes of CMM.

Experience of humanistic nursing in hemodialysis nursing for patients with diabetic kidney disease.

BACKGROUND: Diabetic kidney disease (DKD) is a prevalent complication of diabetes that often requires hemodialysis for treatment. In the field of nursing, there is a growing recognition of the importance of humanistic care, which focuses on the holistic needs of patients, including their emotional, psychological, and social well-being. However, the application of humanistic nursing in the context of hemodialysis for DKD patients remains relatively unexplored. AIM: To explore the experience of humanistic nursing in hemodialysis nursing for DKD patients. METHODS: Ninety-six DKD patients treated with hemodialysis from March 2020 to June 2022 were included in the study and divided into the control cluster (48 cases) and the study cluster (48 cases) according to different nursing methods; the control cluster was given routine nursing and the study cluster was given humanized nursing. The variances of negative emotion mark, blood glucose, renal function, the incidence of complications, life mark and nursing satisfaction before and after nur-sing were contrasted between the two clusters. RESULTS: No significant difference in negative emotion markers between the two clusters were observed before nursing (P > 0.05), and the negative emotion markers of the two clusters decreased after nursing. The Hamilton Anxiety Rating Scale and Hamilton Depression Rating Scale markers were lower in the study cluster than the control cluster. The healing rate of patients in the study cluster was significantly higher than the control cluster (97.92% vs 85.42%, P < 0.05). Blood glucose parameters were not significantly different between the groups prior to nursing (P > 0.05). However, after nursing, blood urea nitrogen and serum creatinine (SCr) levels in the study cluster were lower than those in the control cluster (P < 0.05). The incidence rate of complications was significantly lower in the study group compared to the control cluster (6.25% vs 20.83%, P < 0.05). There was no significant difference in the life markers between the two clusters before nursing. While the life markers increased after nursing for both groups, the 36-item health scale markers in the study cluster were higher than those within the control cluster (P < 0.05). Finally, the nursing satisfaction rate was 93.75% in the study cluster, compared to 75% in the control cluster (P < 0.05). CONCLUSION: In hemodialysis for DKD patients, the implementation of humanistic nursing achieved ideal results, effectively reducing patients' psychological negative emotion markers so that they can actively cooperate with the diagnosis and nursing, facilitate the control of blood glucose and the maintenance of residual renal function, reduce the occurrence of complications, and finally enhance the life quality and nursing satisfaction of patients. It is worthy of being widely popularized and applied.

PABPN1 functions as a hub in the assembly of nuclear poly(A) domains that are essential for mouse oocyte development.

Growing oocytes store a large amount of maternal mRNA to support the subsequent "maternal-zygotic transition" process. At present, it is not clear how the growing oocytes store and process the newly transcribed mRNA under physiological conditions. In this study, we report non-membrane-bound compartments, nuclear poly(A) domains (NPADs), as the hub for newly transcribed mRNA, in developing mouse oocytes. The RNA binding protein PABPN1 promotes the formation of NPAD through its N-terminal disordered domain and RNA-recognized motif by means of liquid phase separation. Pabpn1-null growing oocytes cannot form NPAD normally in vivo and have defects in stability of oocyte growing-related transcripts and formation of long 3' untranslated region isoform transcripts. Ultimately, Pabpn1fl/fl;Gdf9-Cre mice are completely sterile with primary ovarian insufficiency. These results demonstrate that NPAD formed by the phase separation properties of PABPN1-mRNA are the hub of the newly transcribed mRNA and essential for the development of oocytes and female reproduction.

The CNOT4 Subunit of the CCR4-NOT Complex is Involved in mRNA Degradation, Efficient DNA Damage Repair, and XY Chromosome Crossover during Male Germ Cell Meiosis.

The CCR4-NOT complex is a major mRNA deadenylase in eukaryotes, comprising the catalytic subunits CNOT6/6L and CNOT7/8, as well as CNOT4, a regulatory subunit with previously undetermined functions. These subunits have been hypothesized to play synergistic biochemical functions during development. Cnot7 knockout male mice have been reported to be infertile. In this study, viable Cnot6/6l double knockout mice are constructed, and the males are fertile. These results indicate that CNOT7 has CNOT6/6L-independent functions in vivo. It is also demonstrated that CNOT4 is required for post-implantation embryo development and meiosis progression during spermatogenesis. Conditional knockout of Cnot4 in male germ cells leads to defective DNA damage repair and homologous crossover between X and Y chromosomes. CNOT4 functions as a previously unrecognized mRNA adaptor of CCR4-NOT by targeting mRNAs to CNOT7 for deadenylation of poly(A) tails, thereby mediating the degradation of a subset of transcripts from the zygotene to pachytene stage. The mRNA removal promoted by the CNOT4-regulated CCR4-NOT complex during the zygotene-to-pachytene transition is crucial for the appropriate expression of genes involved in the subsequent events of spermatogenesis, normal DNA double-strand break repair during meiosis, efficient crossover between X and Y chromosomes, and ultimately, male fertility.

CNOT6/6L-mediated mRNA degradation in ovarian granulosa cells is a key mechanism of gonadotropin-triggered follicle development.

CCR4-NOT deadenylase is a major regulator of mRNA turnover. It contains two heterogeneous catalytic subunits CNOT7/8 and CNOT6/6L in vertebrates. The physiological function of each catalytic subunit is unclear due to the gene redundancy. In this study, Cnot6/6l double knockout mice are generated. Cnot6l-/- female mice are infertile, with poor ovarian responses to gonadotropins. Follicle-stimulating hormone (FSH) stimulates the transcription and translation of Cnot6 and Cnot6l in ovarian granulosa cells. CNOT6/6L function as key effectors of FSH in granulosa cells and trigger the clearance of specific transcripts in granulosa cells during preantral to antral follicle transition. These results demonstrate that FSH modulates granulosa cell function by stimulating selective translational activation and degradation of existing mRNAs, in addition to inducing de novo gene transcription. Meanwhile, this study provides in vivo evidence that CNOT6/6L-mediated mRNA deadenylation is dispensable in most somatic cell types, but is essential for female reproductive endocrine regulation.

CFP1 coordinates histone H3 lysine-4 trimethylation and meiotic cell cycle progression in mouse oocytes.

Trimethylation of histone H3 on lysine-4 (H3K4me3) is associated with gene-regulatory elements, but its transcription-independent function in cell division is unclear. CxxC-finger protein-1 (CFP1) is a major mediator of H3K4 trimethylation in mouse oocytes. Here we report that oocyte-specific knockout of Cxxc1, inhibition of CFP1 function, or abrogation of H3K4 methylation in oocytes each causes a delay of meiotic resumption as well as metaphase I arrest owing to defective spindle assembly and chromosome misalignment. These phenomena are partially attributed to insufficient phosphorylation of histone H3 at threonine-3. CDK1 triggers cell division-coupled degradation and inhibitory phosphorylation of CFP1. Preventing CFP1 degradation and phosphorylation causes CFP1 accumulation on chromosomes and impairs meiotic maturation and preimplantation embryo development. Therefore, CFP1-mediated H3K4 trimethylation provides 3a permission signal for the G2-M transition. Dual inhibition of CFP1 removes the SETD1-CFP1 complex from chromatin and ensures appropriate chromosome configuration changes during meiosis and mitosis.

CFP1 Regulates Histone H3K4 Trimethylation and Developmental Potential in Mouse Oocytes.

Trimethylation of histone H3 at lysine-4 (H3K4me3) is associated with eukaryotic gene promoters and poises their transcriptional activation during development. To examine the in vivo function of H3K4me3 in the absence of DNA replication, we deleted CXXC finger protein 1 (CFP1), the DNA-binding subunit of the SETD1 histone H3K4 methyltransferase, in developing oocytes. We find that CFP1 is required for H3K4me3 accumulation and the deposition of histone variants onto chromatin during oocyte maturation. Decreased H3K4me3 in oocytes caused global downregulation of transcription activity. Oocytes lacking CFP1 failed to complete maturation and were unable to gain developmental competence after fertilization, due to defects in cytoplasmic lattice formation, meiotic division, and maternal-zygotic transition. Our study highlights the importance of H3K4me3 in continuous histone replacement for transcriptional regulation, chromatin remodeling, and normal developmental progression in a non-replicative system.