microRNA-124 regulates Notch and NeuroD1 to mediate transition states of neuronal development

Zebrafish: A trending model for gut-brain axis investigation

Zebrafish (Danio rerio) has ascended as a pivotal model organism in the realm of gut-brain axis research, principally owing to its high-throughput experimental capabilities and evolutionary alignment with mammals. The inherent transparency of zebrafish embryos facilitates unprecedented real-time imaging, affording unparalleled insights into the intricate dynamics of bidirectional communication between the gut and the brain. Noteworthy are the structural and functional parallels shared between the zebrafish and mammalian gut-brain axis components, rendering zebrafish an invaluable model for probing the molecular and cellular intricacies inherent in this critical physiological interaction. Recent investigations in zebrafish have systematically explored the impact of gut microbiota on neurodevelopment, behaviour, and disease susceptibility, underscoring the model's prowess in unravelling the multifaceted influence of microbial communities in shaping gut-brain interactions. Leveraging the genetic manipulability inherent in zebrafish, researchers have embarked on targeted explorations of specific pathways and molecular mechanisms, providing nuanced insights into the fundamental functioning of the gut-brain axis. This comprehensive review synthesizes pivotal findings and methodological advancements derived from zebrafish-based gut-brain axis research, accentuating the model's potential to significantly advance our understanding of this complex interplay. Furthermore, it underscores the translational significance of these insights, offering promising avenues for the identification of therapeutic targets in neuro-gastroenterological disorders and psychiatric conditions intricately linked with gut-brain interactions.

MicroRNA-124a regulates the differentiation of bone marrow mesenchymal stem cells into neurons

OBJECTIVE

This study investigated the effects of microRNA-124a on the differentiation of bone marrow mesenchymal stem cells (BMSCs) and its underlying mechanism.

METHODS

Flow cytometry was used for isolation and identification of BMSCs. Real-time polymerase chain reaction (RT-PCR) was used to detect gene mRNA expression. Apoptosis was detected using Annexin V-FITC/PI Apoptosis Detection Kit. Cell proliferation ability was tested using Cell Counting Kit-8 (CCK-8). The differentiation of BMSCs into neuron inducers β-thiol ethanol or baicalin formed the basis of the study.

RESULTS

β-thiol ethanol markedly suppressed the microRNA-124a expression of BMSCs, baicalin markedly induced the microRNA-124a expression of BMSCs and β-thiol ethanol or baicalin promoted apoptosis and reduced the growth of BMSCs. Only the microRNA-124a inhibitor did not affect apoptosis or the differentiation of BMSCs, and it increased the effects of β-thiol ethanol or baicalin on the apoptosis of BMSCs.

CONCLUSION

β-thiol ethanol and baicalin treatment could affect microRNA-124a expression in BMSCs. We demonstrated that microRNA-124a promoted the differentiation of BMSCs into neurons.

RNA localization to the mitotic spindle is essential for early development and is regulated by kinesin-1 and dynein

Mitosis is a fundamental and highly regulated process that acts to faithfully segregate chromosomes into two identical daughter cells. Localization of gene transcripts involved in mitosis to the mitotic spindle might be an evolutionarily conserved mechanism to ensure that mitosis occurs in a timely manner. We identified many RNA transcripts that encode proteins involved in mitosis localized at the mitotic spindles in dividing sea urchin embryos and mammalian cells. Disruption of microtubule polymerization, kinesin-1 or dynein results in lack of spindle localization of these transcripts in the sea urchin embryo. Furthermore, results indicate that the cytoplasmic polyadenylation element (CPE) within the 3'UTR of the Aurora B transcript, a recognition sequence for CPEB, is essential for RNA localization to the mitotic spindle in the sea urchin embryo. Blocking this sequence results in arrested development during early cleavage stages, suggesting that RNA localization to the mitotic spindle might be a regulatory mechanism of cell division that is important for early development.

NeuroD1 localizes to the presumptive ganglia and gut of the sea urchin larvae

NeuroD is a transcription factor (TF) that plays a dual role in vertebrate neurogenesis and glucose homeostasis in the pancreas. We identified a NeuroD antibody developed against human that cross-reacts with the sea urchin NeuroD1. NeuroD1 protein localizes to the presumptive ganglia and neurofilament structures in the ciliary band of the sea urchin larvae. In addition, we also observed NeuroD1 in the perinuclear region in the sea urchin gut which is analogous to the mammalian pancreas. These results suggest that NeuroD1 may play an evolutionarily conserved role in the invertebrate sea urchin.