MicroRNA profiling of mouse cortical progenitors and neurons reveals miR-486-5p as a regulator of neurogenesis

Circulating MicroRNAs as a biomarker signature of perinatal asphyxia

AIM

This study aimed to explore whether microRNAs (miRNAs) could serve as biomarkers of perinatal asphyxia and whether they were correlated with severity of brain magnetic resonance imaging.

METHODS

We prospectively enrolled 26 full-term newborns, including 10 with perinatal asphyxia and 16 healthy controls. Plasma samples were collected at 0-6 h and 7 days of age. Encephalopathy was classified according to modified Sarnat staging. Magnetic resonance imaging was performed in surviving infants within 30 days of birth, and a score was established. We used next-generation sequencing to explore differentially expressed miRNAs, which were then further validated using quantitative reverse transcription real-time polymerase chain reaction (RT-PCR).

RESULTS

A significantly lower expression of miR-486-5p was found at 0-6 h of age in the asphyxiated newborns compared with the healthy controls (p = 0.005). The area under the receiver operating characteristic curve (AUC) of miR-486-5p at 0-6 h of age to differentiate the perinatal asphyxia group from the healthy control group was 0.831, and the AUC to differentiate newborns eligible for therapeutic hypothermia from others was 0.782. In addition, a lower expression of miR-486-5p at 7 days of age was noted in the asphyxiated newborns with adverse outcomes compared to those with normal outcomes.

CONCLUSION

MiR-486-5p may be a biomarker of perinatal asphyxia in newborns, and further research is warranted to clarify its role.

MicroRNAs in Umbilical Cord Blood and Development in Full-Term Newborns: A Prospective Study

Background

Exploring the epigenetic regulations, such as microRNA, in newborns holds significant promise for enhancing our ability to address and potentially prevent early-life developmental delays.

Objectives

Hence, this research seeks to investigate if the expression of miRNA in the umbilical cord blood of infants can forecast their developmental outcomes as they grow older.

Design and method

We enrolled 143 full-term newborns, delivered either via cesarean section (CS) or through natural spontaneous delivery (NSD). We then analyzed the profiles of specific miRNAs (miR-486-5p, miR-126-5p, miR-140-3p, miR-151a-3p, miR-142-5p, and miR-30e-5p) in the umbilical cord blood of these infants. Subsequently, we performed follow-up assessments using Bayley-III scores when the cohort reached 1 year of age. Furthermore, we conducted pathway-enrichment analyses on the target genes associated with these examined miRNAs.

Results

When comparing newborns delivered via cesarean section (CS) to those born via natural spontaneous delivery (NSD), we observed notable differences. Specifically, newborns through NSD displayed significantly higher ΔCt values for miR-486-5p, alongside lower ΔCt values for miR-126-5p and miR-151a-3p in their cord blood. At 1 year of age, cognitive development was significantly linked to the ΔCt values of miR-140-3p and miR-142-5p, while language development showed a significant association with the ΔCt values of miR-140-3p. Moreover, our pathway enrichment analyses revealed that the target genes of these miRNAs were consistently involved in the pathways related to neurons, such as axon guidance and the neurotrophin signaling pathway.

Conclusion

In summary, this study represents a pioneering effort in elucidating the potential connections between miRNA levels in cord blood and the health indicators and neurodevelopment of newborns at 1 year of age. Our findings underscore the significance of miRNA levels at birth in influencing mechanisms related to neurodevelopment.

Endogenous neural stem cells characterization using omics approaches: Current knowledge in health and disease

Neural stem cells (NSCs), an invaluable source of neuronal and glial progeny, have been widely interrogated in the last twenty years, mainly to understand their therapeutic potential. Most of the studies were performed with cells derived from pluripotent stem cells of either rodents or humans, and have mainly focused on their potential in regenerative medicine. High-throughput omics technologies, such as transcriptomics, epigenetics, proteomics, and metabolomics, which exploded in the past decade, represent a powerful tool to investigate the molecular mechanisms characterizing the heterogeneity of endogenous NSCs. The transition from bulk studies to single cell approaches brought significant insights by revealing complex system phenotypes, from the molecular to the organism level. Here, we will discuss the current literature that has been greatly enriched in the “omics era”, successfully exploring the nature and function of endogenous NSCs and the process of neurogenesis. Overall, the information obtained from omics studies of endogenous NSCs provides a sharper picture of NSCs function during neurodevelopment in healthy and in perturbed environments.

MicroRNA Profiling of Self-Renewing Human Neural Stem Cells Reveals Novel Sets of Differentially Expressed microRNAs During Neural Differentiation In Vitro

The involvement of microRNAs (miRNAs) in orchestrating self-renewal and differentiation of stem cells has been revealed in a number of recent studies. And while in human pluripotent stem cells, miRNAs have been directly linked to the core pluripotency network, including the cell cycle regulation and the maintenance of the self-renewing capacity, their role in the onset of differentiation in other contexts, such as determination of neural cell fate, remains poorly described. To bridge this gap, we used three model cell types to study miRNA expression patterns: human embryonic stem cells (hESCs), hESCs-derived self-renewing neural stem cells (NSCs), and differentiating NSCs. The comprehensive miRNA profiling presented here reveals novel sets of miRNAs differentially expressed during human neural cell fate determination in vitro. Furthermore, we report a miRNA expression profile of self-renewing human NSCs, which has been lacking to this date. Our data also indicates that miRNA clusters enriched in NSCs share the target-determining seed sequence with cell cycle regulatory miRNAs expressed in pluripotent hESCs. Lastly, our mechanistic experiments confirmed that cluster miR-17-92, one of the NSCs-enriched clusters, is directly transcriptionally regulated by transcription factor c-MYC.

Dynamic miRNA profile of host T cells during early hepatic stages of Schistosoma japonicum infection

Schistosomes undergo complicated migration in final hosts during infection, associated with differential immune responses. It has been shown that CD4⁺ T cells play critical roles in response to Schistosoma infections and accumulated documents have indicated that miRNAs tightly regulate T cell activity. However, miRNA profiles in host T cells associated with Schistosoma infection remain poorly characterized. Therefore, we undertook the study and systematically characterized T cell miRNA profiles from the livers and blood of S. japonicum infected C57BL/6J mice at 14- and 21-days post-infection. We observed 508 and 504 miRNAs, in which 264 miRNAs were co-detected in T cells isolated from blood and livers, respectively. The comparative analysis of T cell miRNAs from uninfected and infected C57BL/6J mice blood showed that miR-486b-5p/3p expression was significantly downregulated and linked to various T cell immune responses and miR-375-5p was highly upregulated, associated with Wnt signaling and pluripotency, Delta notch signaling pathways, etc. Whereas hepatic T cells showed miR-466b-3p, miR-486b-3p, miR-1969, and miR-375 were differentially expressed compared to the uninfected control. The different expressions of some miRNAs were further corroborated in isolated T cells from mice and in vitro cultured EL-4 cells treated with S. japonicum worm antigens by RT-qPCR and similar results were found. In addition, bioinformatics analysis combined with RT-qPCR validation of selected targets associated with the immune system and parasite-caused infectious disease showed a significant increase in the expression of Ctla4, Atg5, Hgf, Vcl and Arpc4 and a decreased expression of Fermt3, Pik3r1, Myd88, Nfkbie, Ppp1r12a, Ppp3r1, Nfyb, Atg12, Ube2n, Tyrobp, Cxcr4 and Tollip. Overall, these results unveil the comprehensive repertoire of T cell miRNAs during S. japonicum infection, suggesting that the circulatory (blood) and liver systems have distinct miRNAs landscapes that may be important for regulating T cell immune response. Altogether, our findings indicated a dynamic expression pattern of T cell miRNAs during the hepatic stages of S. japonicum infection.

miRNA-486-5p: signaling targets and role in non-malignant disease

MicroRNAs (miRNAs) are short non-coding RNAs, highly conserved between species, that are powerful regulators of gene expression. Aberrant expression of miRNAs alters biological processes and pathways linked to human disease. miR-486-5p is a muscle-enriched miRNA localized to the cytoplasm and nucleus, and is highly abundant in human plasma and enriched in small extracellular vesicles. Studies of malignant and non-malignant diseases, including kidney diseases, have found correlations with circulating miR-486-5p levels, supporting its role as a potential biomarker. Pre-clinical studies of non-malignant diseases have identified miR-486-5p targets that regulate major signaling pathways involved in cellular proliferation, migration, angiogenesis, and apoptosis. Validated miR-486-5p targets include phosphatase and tensin homolog (PTEN) and FoXO1, whose suppression activates phosphatidyl inositol-3-kinase (PI3K)/Akt signaling. Targeting of Smad1/2/4 and IGF-1 by miR-486-5p inhibits transforming growth factor (TGF)-β and insulin-like growth factor-1 (IGF-1) signaling, respectively. Other miR-486-5p targets include matrix metalloproteinase-19 (MMP-19), Sp5, histone acetyltransferase 1 (HAT1), and nuclear factor of activated T cells-5 (NFAT5). In this review, we examine the biogenesis, regulation, validated gene targets and biological effects of miR-486-5p in non-malignant diseases.

Therapeutic Potential of Exosomes Derived from Adipose Tissue-Sourced Mesenchymal Stem Cells in the Treatment of Neural and Retinal Diseases

Therapeutic agents that are able to prevent or attenuate inflammation and ischemia-induced injury of neural and retinal cells could be used for the treatment of neural and retinal diseases. Exosomes derived from adipose tissue-sourced mesenchymal stem cells (AT-MSC-Exos) are extracellular vesicles that contain neurotrophins, immunoregulatory and angio-modulatory factors secreted by their parental cells. AT-MSC-Exos are enriched with bioactive molecules (microRNAs (miRNAs), enzymes, cytokines, chemokines, immunoregulatory, trophic, and growth factors), that alleviate inflammation and promote the survival of injured cells in neural and retinal tissues. Due to the nano-sized dimension and bilayer lipid envelope, AT-MSC-Exos easily bypass blood–brain and blood–retinal barriers and deliver their cargo directly into the target cells. Accordingly, a large number of experimental studies demonstrated the beneficial effects of AT-MSC-Exos in the treatment of neural and retinal diseases. By delivering neurotrophins, AT-MSC-Exos prevent apoptosis of injured neurons and retinal cells and promote neuritogenesis. AT-MSC-Exos alleviate inflammation in the injured brain, spinal cord, and retinas by delivering immunoregulatory factors in immune cells, suppressing their inflammatory properties. AT-MSC-Exos may act as biological mediators that deliver pro-angiogenic miRNAs in endothelial cells, enabling re-vascularization of ischemic neural and retinal tissues. Herewith, we summarized current knowledge about molecular mechanisms which were responsible for the beneficial effects of AT-MSC-Exos in the treatment of neural and retinal diseases, emphasizing their therapeutic potential in neurology and ophthalmology.

MicroRNAs Instruct and Maintain Cell Type Diversity in the Nervous System

Characterizing the diverse cell types that make up the nervous system is essential for understanding how the nervous system is structured and ultimately how it functions. The astonishing range of cellular diversity found in the nervous system emerges from a small pool of neural progenitor cells. These progenitors and their neuronal progeny proceed through sequential gene expression programs to produce different cell lineages and acquire distinct cell fates. These gene expression programs must be tightly regulated in order for the cells to achieve and maintain the proper differentiated state, remain functional throughout life, and avoid cell death. Disruption of developmental programs is associated with a wide range of abnormalities in brain structure and function, further indicating that elucidating their contribution to cellular diversity will be key to understanding brain health. A growing body of evidence suggests that tight regulation of developmental genes requires post-transcriptional regulation of the transcriptome by microRNAs (miRNAs). miRNAs are small non-coding RNAs that function by binding to mRNA targets containing complementary sequences and repressing their translation into protein, thereby providing a layer of precise spatial and temporal control over gene expression. Moreover, the expression profiles and targets of miRNAs show great specificity for distinct cell types, brain regions and developmental stages, suggesting that they are an important parameter of cell type identity. Here, we provide an overview of miRNAs that are critically involved in establishing neural cell identities, focusing on how miRNA-mediated regulation of gene expression modulates neural progenitor expansion, cell fate determination, cell migration, neuronal and glial subtype specification, and finally cell maintenance and survival.