HDAC6-dependent deacetylation of NGF dictates its ubiquitination and maintains primordial follicle dormancy.

Rationale: Primordial follicles are limited in number and cannot be regenerated, dormant primordial follicles cannot be reversed once they enter a growth state. Therefore, the length of the female reproductive lifespan depends on the orderly progression and selective activation of primordial follicles, the mechanism of which remains unclear. Methods: We used human ovarian cortical biopsy specimens, granulosa cells from diminished ovarian reserve (DOR) patients, Hdac6-overexpressing transgenic mouse model, and RNA sequencing to analyze the crucial roles of histone deacetylase 6 (HDAC6) in fertility preservation and primordial follicle activation. Results: In the present study, we found that HDAC6 was highly expressed in most dormant primordial follicles. The HDAC6 expression was reduced accompanying reproductive senescence in human and mouse ovaries. Overexpression of Hdac6 delayed the rate of primordial follicle activation, thereby prolonging the mouse reproductive lifespan. Short-term inhibition of HDAC6 promoted primordial follicle activation and follicular development in humans and mice. Mechanism studies revealed that HDAC6 directly interacted with NGF, reducing acetylation modification of NGF and thereby accelerating its ubiquitination degradation. Consequently, the reduced NGF protein level maintained the dormancy of primordial follicles. Conclusions: The physiological significance of the high expression of HDAC6 in most primordial follicles is to reduce NGF expression and prevent primordial follicle activation to maintain female fertility. Reduced HDAC6 expression increases NGF expression in primordial follicles, activating their development and contributing to reproduction. Our study provides a clinical reference value for fertility preservation.

Exploring the interaction of cognition and emotion in small group collaborative discourse by Heuristic Mining Algorithm (HMA) and Inductive Miner Algorithm (IMA).

This study explored the interaction between cognition and emotion in blended collaborative learning. The participants (n = 30) of this study were undergraduate students enrolled in a 16-week course on information technology teaching. These students were divided into six groups of five people each. The behavior modes of the participants were analyzed using a heuristic mining algorithm and inductive miner algorithm. Compared with the groups with low task scores, the high-scoring groups exhibited more reflection phases and cycles in the interaction process and thus more frequent self-evaluation and regulation behavior for forethought and performance. Moreover, the frequency of emotion events unrelated with cognition was higher for the high-scoring groups than for the low-scoring groups. On the basis of the research results, this paper presents suggestions for developing online and offline blended courses.

Improving the Behavioral Intention of Continuous Online Learning Among Learners in Higher Education During COVID-19.

The COVID-19 pandemic caused colleges and universities to rely heavily on online learning to continue knowledge dissemination to learners. This study used the second-generation model of unified theory of acceptance and use of technology (UTAUT2) to comprehensively analyze the mediating effects of self-efficacy, which affects learners' effective use of online tools for learning, and capability of metacognition and self-regulation, which can independently adjust learning progress into the UTAUT2 model, on the learner's willingness to continue online learning [i.e., their behavioral intention (BI)] by constructing a UTAUT2-based e-learning model. This study administered questionnaires to undergraduates in universities in East China to collect data. The effects of performance expectancy, effort expectancy (EE), social influence (SI), and facilitating conditions (FCs), hedonic motivation (HM), price value (PV), and habits on BI (directly or through mediators) were analyzed through data analysis and structural equation modeling, and the UTAUT2-based e-learning model was accordingly modified. The results indicated that the self-efficacy enhanced the effects of EE, SI, FCs, HM, and PV on learners' BI; that metacognition and self-regulation (MS) capabilities enhanced the effects of EE on learners' BI; and that habits had a direct and strong effect on BI. This study also provided some suggestions to enhance higher education learners' willingness to continue online learning, such as improving social recognition and support, careful design of teaching content, easy-to-use technology, financial support. These results and suggestions may guide colleges and universities in conducting, continuing, or enhancing online education, particularly as the pandemic continues.

miR-25 and miR-92b regulate insulin biosynthesis and pancreatic ß-cell apoptosis.

PURPOSE: Pancreatic ß-cell failure is a central hallmark of the pathogenesis of diabetes mellitus; however, the molecular basis underlying chronic inflammation-caused ß-cell failure remains unclear. This study reported here specifically assessed the association between miR-25/miR-92b family and ß-cell failure in diabetes. METHODS: IL-1ß and two additional ER stress activators, palmitate and tunicamycin were applied to evaluate the expression level miR-25 by Taqman® RT-PCR. Glucose- and potassium-stimulated insulin secretion assays were performed to assess ß-cell function. Dual-luciferase activity, and western blotting assays were utilized for miR-25 target gene verification. CCK-8 and TUNEL staining were used to evaluate ß-cell viability and apoptosis. RESULTS: miRNA ChIP identified the increased level of miR-25 in INS-1 cells by IL-1ß treatment. Expression levels of miR-25 were significantly upregulated with the treatment of IL-1ß, palmitate or tunicamycin in both INS-1 cells and human islets. Ectopic elevation of miR-25 recapitulated most featured ß-cell defects caused by IL-1ß, including inhibition of insulin biosynthesis and increased ß-cell apoptosis. These detrimental effects of miR-25 relied on its seed sequence recognition and repressed expression of its target genes Neurod1 and Mcl1. The miR-25/NEUROD1 axis reduced insulin biosynthesis via transcriptional regulation of ß-cell specific genes. The miR-25/MCL1 axis caused ß-cell apoptosis in a CASPASE-3/PARP1-dependent manner. Comparable impairments were generated by miR-92b and miR-25, emphasizing the redundant biological roles of miRNA family members with the same seed sequence. CONCLUSION: MiR-25/miR-92b family plays a major role in ß-cell failure occurring under inflammation and diabetes states.

Role of the cofilin 2 gene in regulating the myosin heavy chain genes in mouse myoblast C2C12 cells.

The cofilin 2 (CFL2) and myosin heavy chain (MyHC) genes play a key role in muscle development and myofibrillar formation. The aim of the present study was to investigate the effect of CFL2 on genes involved in fiber formation and the mechanisms underlying this process. Undifferentiated and differentiated C2C12 cells (UDT and DT, respectively) were transfected with CFL2 small interfering RNA (siRNA). CFL2 mRNA and protein levels were assessed using reverse transcription polymerase chain reaction (RT-PCR) and western blotting, respectively. MyHC gene expression in UDT and signaling pathway-related factors were observed with quantitative PCR (RT­qPCR) and western blotting. Fluorescence microscopy was used to analyze the cytoskeletal effects of CFL2. The mRNA and protein expressions of CFL2, four MyHC isoforms (MyHC-I, MyHC-IIa, MyHC-IIb and MyHC-IIx), p38 mitogen-activated protein kinase, cAMP-response element-binding protein, AMP-activated protein kinase α1, and myocyte enhancer factor 2C, were significantly decreased in UDT. However, extracellular signal-regulated kinase 2 expression was significantly increased. Slightly decreased CFL2 protein and mRNA expression was observed in DT C2C12 cells transfected with CFL2 siRNA. Fluorescence microscopy revealed a significant decrease of CFL2 in the cytoplasm, but not the nucleus, of UDT, compared with normal cells. These results indicated that the mouse CFL2 gene may be involved in the regulation of MyHC via the key signaling molecules of CFL2-related signaling pathways.