BACKGROUND: Brain organoids are believed to be able to regenerate impaired neural circuits and reinstate brain functionality. The neuronal activity of organoids is considered a crucial factor for restoring host function after implantation. However, the optimal stage of brain organoid post-transplantation has not yet been established. External electrical signal plays a crucial role in the physiology and development of a majority of human tissues. However, whether electrical input modulates the development of brain organoids, making them ideal transplant donors, is elusive.
METHODS: Bioelectricity was input into cortical organoids by electrical stimulation (ES) with a multi-electrode array (MEA) to obtain a better-transplanted candidate with better viability and maturity, realizing structural-functional integration with the host brain.
RESULTS: We found that electrical stimulation facilitated the differentiation and maturation of organoids, displaying well-defined cortical plates and robust functional electrophysiology, which was probably mediated via the pathway of calcium-calmodulin (CaM) dependent protein kinase II (CAMK II)-protein kinase A (PKA)-cyclic-AMP response binding protein (pCREB). The ES-pretreated D40 organoids displayed superior cell viability and higher cell maturity, and were selected to transplant into the damaged primary sensory cortex (S1) of host. The enhanced maturation was exhibited within grafts after transplantation, including synapses and complex functional activities. Moreover, structural-functional integration between grafts and host was observed, conducive to strengthening functional connectivity and restoring the function of the host injury.
CONCLUSIONS: Our findings supported that electrical stimulation could promote the development of cortical organoids. ES-pretreated organoids were better transplanted donors for strengthening connectivity between grafts and host. Our work presented a new physical approach to regulating organoids, potentially providing a novel translational strategy for functional recovery after brain injury. In the future, the development of 3D flexible electrodes is anticipated to overcome the drawbacks of 2D planar MEA, promisingly achieving multimodal stimulation and long-term recordings of brain organoids.

To induce sexual maturation in captivity, eels rely on hormonal treatments, but this process is costly and time-consuming. As an alternative, different types of conditioning, also referred as pre-treatment, have been assessed to ease hormonal treatment response. Recent studies have shown that migrating eels experience a wide range of temperatures, varying from 12 °C at night to as low as to 8 °C during the day. Therefore, this study evaluates the effects of low-temperature (10 °C) seawater pre-treatments of different durations (2 and 4 weeks) on male eel reproduction. The eye, gonadosomatic and hepatosomatic indexes from control (without thermic seawater pre-treatment) and pre-treated fish were measured. Blood and testis samples were also collected for sex steroid and histology analysis, respectively. Eels pre-treated for 2 weeks demonstrated increased progestin levels, comparing with the control group. Eels pre-treated for 4 weeks showed significantly higher gonadosomatic index and elevated androgens and estradiol levels in comparison with the remaining groups. In eels pre-treated for 2 and 4 weeks, there was an increase in the proportion of spermatogonia type B cells compared to undifferentiated spermatogonia type A, a differentiation process that was not observed in the control group. Cold seawater pre-treatment induced early sexual maturation, including steroid production, which consequently stimulated biometric changes and increased spermatogonia differentiation. Following the pre-treatments, eels started receiving standard hormonal treatment (with recombinant human chorionic gonadotropin at 20 °C). Pre-treated males started to spermiate earlier than the control group. In some treatment weeks, pre-treated individuals registered higher values of sperm density, motility, and kinetic parameters. Moreover, an economic evaluation was carried out relating the investment made in terms of hormone injections with the volume of high-quality sperm obtained from each experimental group. The low temperature pre-treatments demonstrated their economic effectiveness in terms of hormone treatment profitability, increasing the production of high-quality sperm in the European eel. Thus, this in vivo study suggests that cold seawater pre-treatment may increase sensitivity to the hormone applied during standard maturation treatment.

The volatile profiles of wheat flour during maturation were examined through headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with electronic nose (E-nose) and electronic tongue (E-tongue) analyses. The wheat flour underwent maturation under three distinct conditions for predetermined durations. While GC/MS coupled with E-tongue exhibited discernment capability among wheat flour samples subjected to varying maturation conditions, E-nose analysis solely relying on principal component analysis failed to achieve discrimination. 83 volatile compounds were identified in wheat flour, with the highest abundance observed in samples matured for 50 d at 25 °C. Notably, trans-2-Nonenal, decanal, and nonanal were the main contributors to the characteristic flavor profile of wheat flour. Integration of HS-SPME-GC/MS with E-tongue indicated superior flavor development and practical viability in wheat flour matured for 50 d at 25 °C. This study furnishes a theoretical groundwork for enhancing the flavor profiles of wheat flour and its derivative products.

Football is a team sport played worldwide and specific competition demands are needed since young categories. Several physiological and psychological aspects could influence the selection process, and adolescent investigations still be necessary. This retrospective study aims to compare anthropometric and performance features between selected and unselected adolescent footballers. The sample size was 78 players from U10 to U12 categories. Maturation, RAE, anthropometry, and physical performance (repeated sprint ability (RSA), 15-m sprint, countermovement jump (CMJ) and Harre\'s test) were evaluated (mean ± SD). 33.3 % of players were selected (height = 144.06 ± 6.74 cm, weight = 35.38 ± 4.56 kg) and 66.7 % were unselected (height = 143.06 ± 8.34 cm, weight = 35.94 ± 6.24 kg). Selected U10 were leaner and got the peak of height velocity (APHV) earlier (p < 0.05) than unselected U10 players, while U11 selected were faster than unselected (p < 0.05). Also, the RSA test, APHV and the humeral width well discriminated among the selection (χ 2 (3) = 12; p < 0.01). Football field technicians involved in scouting need quantitative and qualitative information that could help to predict talented players. Although physical performance test results and body height led to decisions, further anthropometric features and maturation could provide relevant support.

The adult mammalian heart has extremely limited cardiac regenerative capacity. Most cardiomyocytes live in a state of permanent cell-cycle arrest and are unable to re-enter the cycle. Cardiomyocytes switch from cell proliferation to a maturation state during neonatal development. Although several signaling pathways are involved in this transition, the molecular mechanisms by which these inputs coordinately regulate cardiomyocyte maturation are not fully understood. Retinoic acid (RA) plays a pivotal role in development, morphogenesis, and regeneration. Despite the importance of RA signaling in embryo heart development, little is known about its function in the early postnatal period. We found that mRNA expression of aldehyde dehydrogenase 1 family member A2 (Aldh1a2), which encodes the key enzyme for synthesizing all-trans retinoic acid (ATRA) and is an important regulator for RA signaling, was transiently upregulated in neonatal mouse ventricles. Single-cell transcriptome analysis and immunohistochemistry revealed that Aldh1a2 expression was enriched in cardiac fibroblasts during the early postnatal period. Administration of ATRA inhibited cardiomyocyte proliferation in cultured neonatal rat cardiomyocytes and human cardiomyocytes. RNA-seq analysis indicated that cell proliferation-related genes were downregulated in prenatal rat ventricular cardiomyocytes treated with ATRA, while cardiomyocyte maturation-related genes were upregulated. These findings suggest that RA signaling derived from cardiac fibroblasts is one of the key regulators of cardiomyocyte proliferation and maturation during neonatal heart development.

Microglia are the resident immune cells of the brain. As such, they rapidly detect changes in normal brain homeostasis and accurately respond by fine-tuning in a tightly regulated manner their morphology, gene expression, and functional behavior. Depending on the nature of these changes, microglia can thicken and retract their processes, proliferate and migrate, release numerous signaling factors and compounds influencing neuronal physiology (e.g., cytokines and trophic factors), in addition to secreting proteases able to transform the extracellular matrix, and phagocytosing various types of cellular debris, etc. Because microglia also transform rapidly (on a time scale of minutes) during experimental procedures, studying these very special cells requires methods that are specifically non-invasive. The development of such methods has provided unprecedented insights into the roles of microglia during normal physiological conditions. In particular, transcranial two-photon in vivo imaging revealed that presumably \"resting\" microglia continuously survey the brain parenchyma with their highly motile processes, in addition to modulating their structural and functional interactions with neuronal circuits along the changes in neuronal activity and behavioral experience occurring throughout the lifespan. In this chapter, we will describe how surveillant microglia interact with synaptic elements and modulate the number, maturation, function, and plasticity of synapses in the healthy developing, mature, and aging brain, with consequences on neuronal activity, learning and memory, and the behavioral outcome.

The words that children learn change over time in predictable ways. The first words that infants acquire are generally ones that are both frequent and highly imageable. Older infants also learn words that are more abstract and some that are less common. It is unclear whether this pattern is attributable to maturational factors (i.e., younger children lack sufficiently developed cognitive faculties needed to learn abstract words) or linguistic factors (i.e., younger children lack sufficient knowledge of their language to use grammatical or contextual cues needed to figure out the meaning of more abstract words). The present study explores this question by comparing vocabulary acquisition in 53 preschool-aged children (M = 51 months, range = 30-76 months) who were adopted from China and Eastern Europe after two and half years of age and 53 vocabulary-matched infant controls born and raised in English speaking families in North America (M = 24 months, range = 16-33 months). Vocabulary was assessed using the MB-CDI Words and Sentences form, word frequency was estimated from the CHILDES database, and imageability was measured using adult ratings of how easily words could be pictured mentally. Both groups were more likely to know words that were both highly frequent and imageable (resulting in an over-additive interaction). Knowledge of a word was also independently affected by the syntactic category that it belongs to. Adopted preschoolers\' vocabulary was slightly less affected by imageability. These findings were replicated in a comparison with a larger sample of vocabulary-matched controls drawn from the MB-CDI norming study (M = 22 months, range = 16-30 months; 33 girls). These results suggest that the patterns of acquisition in children\'s early vocabulary are primarily driven by the accrual of linguistic knowledge, but that vocabulary may also be affected by differences in early life experiences or conceptual knowledge.

BACKGROUND: Within the follicular fluid, extracellular vesicles (EVs) guide oocyte growth through their cargo microRNAs (miRNAs). Here, we investigated the role of EVs and their cargo miRNAs by linking the miRNAs found in EVs, derived from the fluid of an individual follicle, to the ability of its oocyte to become a blastocyst (competent) or not (non-competent).
METHODS: Bovine antral follicles were dissected, categorized as small (2-4 mm) or large (5-8 mm) and the corresponding oocytes were subjected to individual maturation, fertilization and embryo culture to the blastocyst stage. Follicular fluid was pooled in 4 groups (4 replicates) based on follicle size and competence of the corresponding oocyte to produce a blastocyst. Follicular fluid-derived EVs were isolated, characterized, and subjected to miRNA-sequencing (Illumina Miseq) to assess differential expression (DE) in the 4 groups. Functional validation of the effect of miR-34c on embryo development was performed by supplementation of mimics and inhibitors during in vitro maturation (IVM).
RESULTS: We identified 16 DE miRNAs linked to oocyte competence when follicular size was not considered. Within the large and small follicles, 46 DE miRNAs were driving blastocyst formation in each group. Comparison of EVs from competent small and large follicles revealed 90 DE miRNAs. Cell regulation, cell differentiation, cell cycle, and metabolic process regulation were the most enriched pathways targeted by the DE miRNAs from competent oocytes. We identified bta-miR-34c as the most abundant in follicular fluid containing competent oocytes. Supplementation of miR-34c mimic and inhibitor during IVM did not affect embryo development. However, blastocyst quality, as evidenced by higher cell numbers, was significantly improved following oocyte IVM in the presence of miR-34c mimics, while miR-34c inhibitors resulted in the opposite effect.
CONCLUSIONS: This study demonstrates the regulatory effect of miRNAs from follicular fluid-derived EVs on oocyte competence acquisition, providing a further basis for understanding the significance of miRNAs in oocyte maturation and embryonic development. Up-regulation of miR-34c in EVs from follicular fluid containing competent oocytes and the positive impact of miR-34c mimics added during IVM on the resulting blastocysts indicate its pivotal role in oocyte competence.

Advanced glycation end products (AGEs) are the final products of the Maillard reaction, formed through the interaction of carbohydrates and proteins. Reactive dicarbonyl compounds such as methylglyoxal (MGO) serve as precursors for AGEs formation. Elevated levels of MGO/AGEs are observed in conditions like obesity, polycystic ovarian syndrome (PCOS), and diabetes, negatively impacting oocyte development. Previous studies have shown that hydrogen sulfide, a gasotransmitter with anti-AGEs effects, is produced in a process influenced by vitamin B6. R-α-lipoic acid (ALA) inhibits protein glycation and AGEs formation while stimulating glutathione (GSH) production. Taurine mitigates oxidative stress and acts as an anti-glycation compound, preventing in vitro glycation and AGEs accumulation. This study aimed to explore the ameliorative effects of a micronutrient support (Taurine, ALA and B6: TAB) on mouse oocytes challenged with MGO. Our results indicate that MGO reduces oocyte developmental competence, while TAB supplementation improves maturation, fertilization, and blastocyst formation rates. TAB also restores cell lineage allocation, redox balance and mitigates mitochondrial dysfunction in MGO-challenged oocytes. Furthermore, cumulus cells express key enzymes in the transsulfuration pathway, and TAB enhances their mRNA expression. However, TAB does not rescue MGO-induced damage in denuded oocytes, emphasizing the supportive role of cumulus cells. Overall, these findings suggest that TAB interventions may have significant implications for addressing reproductive dysfunctions associated with elevated MGO/AGEs levels. This study highlights the potential of TAB supplementation in preserving the developmental competence of COCs exposed to MGO stress, providing insights into mitigating the impact of dicarbonyl stress on oocyte quality and reproductive outcomes.

Sertoli cells, omnipresent, somatic cells within the seminiferous tubules of the mammalian testis are essential to male fertility. Sertoli cells maintain the integrity of the testicular microenvironment, regulate hormone synthesis, and of particular importance, synthesize the active derivative of vitamin A, all trans retinoic acid (atRA), which is required for germ cell differentiation and the commitment of male germ cells to meiosis. Stages VIII-IX, when atRA synthesis occurs in the testis, coincides with multiple germ cell development and testicular restructuring events that rely on Sertoli cell gene products to proceed normally. In this study, we have synchronized and captured the mouse testis at four recurrent points of atRA synthesis to observe transcriptomic changes within Sertoli cells as mice age and the Sertoli cells are exposed to increasingly developed germ cell subtypes. This work provides comprehensive, high-resolution characterization of the timing of induction of functional Sertoli cell genes across the first wave of spermatogenesis, and outlines in silico predictions of germ cell derived signaling mechanisms targeting Sertoli cells. We have found that Sertoli cells adapt to their environment, especially to the needs of the germ cell populations present and establish germ-Sertoli cell and Sertoli-Sertoli cell junctions early, but gain many of their known immune-regulatory and protein secretory functions in preparation for spermiogenesis and spermiation. Additionally, we have found unique patterns of germ-Sertoli signaling present at each endogenous pulse of atRA, suggesting individual functions of the various germ cells in germ-Sertoli communication.