Increasing evidence indicated that neuroinflammation was involved in progression of Parkinson\'s disease (PD). Long noncoding RNAs (lncRNAs) played important roles in regulating inflammatory processes in multiple kinds of human diseases such as cancer diabetes, cardiomyopathy, and neurodegenerative disorders. The mechanisms by which lncRNAs regulated PD related inflammation and dopaminergic neuronal loss have not yet been fully elucidated. In current study, we intended to explore the function and potential mechanism of lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in regulating inflammasome activation in PD. Functional assays confirmed that knockdown of KCNQ1OT1 suppress microglial NLR family pyrin domain containing 3 (NLRP3) inflammasome activation and attenuated dopaminergic neuronal loss in PD model mice. As KCNQ1OT1 located in both cytoplasm and nucleus of microglia, we demonstrated that KCNQ1OT1 promoted microglial NLRP3 inflammasome activation by competitive binding with miR-186 in cytoplasm and inhibited pri-miR-186 mediated NLRP3 silencing through recruitment of DiGeorge syndrome critical region gene 8 (DGCR8) in nucleus, respectively. Our study found a novel lncRNA-pri-miRNA/mature miRNA-mRNA regulatory network in microglia mediated NLRP3 inflammasome activation and dopaminergic neuronal loss, provided further insights for the treatment of Parkinson\'s disease.

During implantation, embryos undergo an unpolarized-to-polarized transition to initiate postimplantation morphogenesis. However, the underlying molecular mechanism is unknown. Here, we identify a transient transcriptional activation governing embryonic morphogenesis and pluripotency transition during implantation. In naive pluripotent embryonic stem cells (ESCs), which represent preimplantation embryos, we find that the microprocessor component DGCR8 can recognize stem-loop structures within nascent mRNAs to sequester transcriptional coactivator FLII to suppress transcription directly. When mESCs exit from naive pluripotency, the ERK/RSK/P70S6K pathway rapidly activates, leading to FLII phosphorylation and disruption of DGCR8/FLII interaction. Phosphorylated FLII can bind to transcription factor JUN, activating cell migration-related genes to establish poised pluripotency akin to implanting embryos. Resequestration of FLII by DGCR8 drives poised ESCs into formative pluripotency. In summary, we identify a DGCR8/FLII/JUN-mediated transient transcriptional activation mechanism. Disruption of this mechanism inhibits naive-poised-formative pluripotency transition and the corresponding unpolarized-to-polarized transition during embryo implantation, which are conserved in mice and humans.

MicroRNAs (miRNAs) act as negative regulators for protein-coding gene expression impacting cell proliferation, differentiation, and survival. These miRNAs are frequently dysregulated in cancer and constitute classes of blood-based biomarkers useful for cancer detection and prognosis definition. In thyroid cancer (TC), the miRNA biogenesis pathway plays a pivotal role in thyroid gland formation, ensuring proper follicle development and hormone production. Several alterations in the miRNA biogenesis genes are reported as a causality for miRNA dysregulation. Mutations in microprocessor component genes are linked to an increased risk of developing TC; in particular, a recurrent mutation affecting DGCR8, the E518K. In this review, we explore these novel findings and resume the current state-of-the-art in miRNAs in thyroid carcinomas.

The DGCR8 gene, encoding a critical miRNA processing protein, maps within the hemizygous region in patients with 22q11.2 deletion syndrome. Most patients have malformations of the cardiac outflow tract that is derived in part from the anterior second heart field (aSHF) mesoderm. To understand the function of Dgcr8 in the aSHF, we inactivated it in mice using Mef2c-AHF-Cre. Inactivation resulted in a fully penetrant persistent truncus arteriosus and a hypoplastic right ventricle leading to lethality by E14.5. To understand the molecular mechanism for this phenotype, we performed gene expression profiling of the aSHF and the cardiac outflow tract with right ventricle in conditional null versus normal mouse littermates at stage E9.5 prior to morphology changes. We identified dysregulation of mRNA gene expression, of which some are relevant to cardiogenesis. Many pri-miRNA genes were strongly increased in expression in mutant embryos along with reduced expression of mature miRNA genes. We further examined the individual, mature miRNAs that were decreased in expression along with pri-miRNAs that were accumulated that could be direct effects due to loss of Dgcr8. Among these genes, were miR-1a, miR-133a, miR-134, miR143 and miR145a, which have known functions in heart development. These early mRNA and miRNA changes may in part, explain the first steps that lead to the resulting phenotype in Dgcr8 aSHF conditional mutant embryos.

The Microprocessor complex (MP) is a vital component in the biogenesis of microRNAs (miRNAs) in animals. It plays a crucial role in the biogenesis of microRNAs (miRNAs) in mammals as it cleaves primary miRNAs (pri-miRNAs) to initiate their production. The accurate enzymatic activity of MP is critical to ensuring proper sequencing and expression of miRNAs and their correct cellular functions. RNA elements in pri-miRNAs, including secondary structures and sequencing motifs, RNA editing and modifications, and cofactors, can impact MP cleavage and affect miRNA expression and sequence. To evaluate MP cleavage activity with various RNA substrates under different conditions, we set up an in vitro pri-miRNA cleavage assay. This involves purifying human MP from HEK293E cells, synthesizing pri-miRNAs using in vitro transcription, and performing pri-miRNA cleavage assays using basic laboratory equipment and reagents. These procedures can be performed in various labs and improved for high-throughput analysis of enzymatic activities with thousands of RNA substrates.

Microprocessor (MP), DROSHA-DGCR8, processes primary miRNA transcripts (pri-miRNAs) to initiate miRNA biogenesis. The canonical cleavage mechanism of MP has been extensively investigated and comprehensively validated for two decades. However, this canonical mechanism cannot account for the processing of certain pri-miRNAs in animals. In this study, by conducting high-throughput pri-miRNA cleavage assays for approximately 260,000 pri-miRNA sequences, we discovered and comprehensively characterized a noncanonical cleavage mechanism of MP. This noncanonical mechanism does not need several RNA and protein elements essential for the canonical mechanism; instead, it utilizes previously unrecognized DROSHA dsRNA recognition sites (DRESs). Interestingly, the noncanonical mechanism is conserved across animals and plays a particularly significant role in C. elegans. Our established noncanonical mechanism elucidates MP cleavage in numerous RNA substrates unaccounted for by the canonical mechanism in animals. This study suggests a broader substrate repertoire of animal MPs and an expanded regulatory landscape for miRNA biogenesis.

miRNAs, small non-coding RNAs that regulate gene expression, are involved in various pathological processes, including viral infections. Virus infections may interfere with the miRNA pathway through the inhibition of genes involved in miRNA biogenesis. A reduction in the number and the levels of miRNAs expressed in nasopharyngeal swabs of patients with severe COVID-19 was lately observed by us, pointing towards the potential of miRNAs as possible diagnostic or prognostic biomarkers for predicting outcomes among patients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. The objective of the present study was to investigate whether SARS-CoV-2 infection influences the expression levels of messenger RNAs (mRNAs) of key genes involved in miRNA biogenesis. mRNA levels of AGO2, DICER1, DGCR8, DROSHA, and Exportin-5 (XPO5) were measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR) in nasopharyngeal swab specimens from patients with COVID-19 and controls, as well as in cells infected with SARS-CoV-2 in vitro. Our data showed that the mRNA expression levels of AGO2, DICER1, DGCR8, DROSHA, and XPO5 were not significantly different in patients with severe COVID-19 when compared to patients with non-severe COVID-19 and controls. Similarly, the mRNA expression of these genes was not affected by SARS-CoV-2 infection in NHBE and Calu-3 cells. However, in Vero E6 cells, AGO2, DICER1, DGCR8, and XPO5 mRNA levels were slightly upregulated 24 h after infection with SARS-CoV-2. In conclusion, we did not find evidence for downregulation of mRNA levels of miRNA biogenesis genes during SARS-CoV-2 infection, neither ex vivo nor in vitro.

Oral squamous cell carcinoma (OSCC) remains the most prevalent malignance in the head and neck with highly aggressive attributes. This study investigates the functions of nuclear receptor interacting protein 1 (NRIP1) and its target transcripts in the progression of OSCC. By analyzing four OSCC-related Gene Expression Omnibus (GEO) datasets (GSE9844, GSE23558, GSE25104 and GSE74530) and querying bioinformatics systems, we obtained NRIP1 as an aberrantly highly expressed transcription factor in OSCC. Increased NRIP1 was detected in OSCC cell lines. Artificial downregulation of NRIP1 significantly suppressed proliferation, migration and invasion, resistance to apoptosis, tumorigenicity, and in vivo metastatic potential of OSCC cells. Moreover, the bioinformatics analyses suggested nuclear receptor binding SET domain protein 2 (NSD2) as a target of NRIP1 and DGCR8 microprocessor complex subunit (DGCR8) as a target of NSD2. Indeed, we validated by chromatin immunoprecipitation and luciferase assays that NRIP1 activated the transcription of NSD2, and NSD2 increased DGCR8 transcription by modulating histone methylation near the DGCR8 promoter. Either NSD2 or DGCR8 upregulation in OSCC cells rescued their malignant properties. Collectively, this study demonstrates that NRIP1 augments malignant properties of OSCC cells by activating NSD2-mediated histone methylation of DGCR8.

We have previously shown that the microRNA (miRNA) processor complex consisting of the RNAse Drosha and the DiGeorge Critical Region (DGCR) 8 protein is essential for B cell maturation. To determine whether miRNA processing is required to initiate T cell-mediated antibody responses, we deleted DGCR8 in maturing B2 cells by crossing a mouse with loxP-flanked DGCR8 alleles with a CD23-Cre mouse. As expected, non-immunized mice showed reduced numbers of mature B2 cells and IgG-secreting cells and diminished serum IgG titers. In accordance, germinal centers and antigen-specific IgG-secreting cells were absent in mice immunized with T-dependent antigens. Therefore, DGCR8 is required to mount an efficient T-dependent antibody response. However, DGCR8 deletion in B1 cells was incomplete, resulting in unaltered B1 cell numbers and normal IgM and IgA titers in DGCR8-knock-out mice. Therefore, this mouse model could be used to analyze B1 responses in the absence of functional B2 cells.

DGCR8 emerged recently as miRNAs biogenesis pathway protein with a highlighted role in thyroid disease. This study aimed to characterize this miRNA biogenesis component, in particular the p.(E518K) mutation and DGCR8 expression in a series of thyroid lesions. The series of thyroid lesions was genotyped for the c.1552G>A p.(E518K) mutation. When frozen tissue was available, DGCR8 mRNA expression was analysed by qPCR. Formalin-fixed paraffin-embedded tissues were studied for DGCR8 immunoexpression. We present for the first time the p.(E518K) mutation in a case of poorly differentiated thyroid carcinoma and present the deregulation of DGCR8 expression at mRNA level in follicular-patterned tumours. The obtained data solidify DGCR8 as another important player of miRNA-related gene mutations in thyroid tumorigenesis, particularly in follicular-patterned thyroid tumours.