Long Noncoding RNA Signatures Induced by Toll-Like Receptor 7 and Type I Interferon Signaling in Activated Human Plasmacytoid Dendritic Cells

Cryptococcosis Inhibits the Immune Response of Dendritic Cells Through the snhg1-miR-145a-3p-Bcl2 Axis

OBJECTIVES

Dendritic cells are one of the first host cells that cryptococcus encounters. However, the correlations among cryptococcus, dendritic cells, and long noncoding RNA remain unclear. This study was undertaken to investigate the effects of long noncoding RNAs on dendritic cells with cryptococcus infection.

MATERIALS AND METHODS

We treated dendritic cells with cryptococcus and then detected expression of CD80, CD86, and major histocompatibility complex class II in dendritic cells with a real-time fluorescent quantitative polymerase chain reaction assay. We used nextgeneration sequencing and bioinformatics analysis to determine the competitive endogenous RNA mechanisms, confirmed via real-time polymerase chain reaction, dual luciferase reporter, and RNA-binding protein immunoprecipitation assays.

RESULTS

After treatment of dendritic cells with 1 × 108 CFU/mL cryptococcus for 12 hours, dendritic cell viability was normal, whereas mRNA expression levels of CD80, CD86, and major histocompatibility complex class II in dendritic cells were substantially increased. With next-generation sequencing, we discovered 4 small nucleolar RNA host genes (snhg1, snhg3, snhg4, and snhg16) in cryptococcus-treated dendritic cells compared with wild-type dendritic cells. Bioinformatics analysis combined with real-time polymerase chain reaction led us to speculate that cryptococcus may affect the maturation and apoptosis of dendritic cells by regulating snhg1-miR-145a-3p-Bcl2. Further polymerase chain reaction, dual luciferase reporter, and RNA-binding protein immunoprecipitation experiments revealed that snhg1 acted as a sponge for miR145a-3p to inhibit the expression of miR-145a-3p and that miR-145a-3p promoted the expression of Bcl2 by directly targeting the 3'-UTR of Bcl2. Functional recovery experiments showed that cryptococcus promoted the maturation and apoptosis and inhibited the proliferation of dendritic cells through the snhg1-Bcl2 pathway.

CONCLUSIONS

This study lays a foundation for the further understanding of the pathogenic role of snhg1-miR-145a-3p-Bcl2 axis in cryptococcosis.

Roles of RNA-binding proteins in immune diseases and cancer

Genetic information that is transcribed from DNA to mRNA, and then translated from mRNA to protein, is regulated by complex and sophisticated post-transcriptional mechanisms. Recently, it has become clear that mRNA degradation not only acts to remove unnecessary mRNA, but is also closely associated with the regulation of translation initiation, and is essential for maintaining cellular homeostasis. Various RNA-binding proteins (RBPs) have been reported to play central roles in the mechanisms of mRNA stability and translation initiation through various signal transduction pathways, and to modulate gene expression faster than the transcription process via post-transcriptional modifications in response to intracellular and extracellular stimuli, without de novo protein synthesis. On the other hand, inflammation is necessary for the elimination of pathogens associated with infection, and is tightly controlled to avoid the overexpression of inflammatory cytokines, such as interleukin 6 (IL-6) and tumor necrosis factor (TNF). It is increasingly becoming clear that RBPs play important roles in the post-transcriptional regulation of these immune responses. Furthermore, it has been shown that the aberrant regulation of RBPs leads to chronic inflammation and autoimmune diseases. Although it has been recognized since the time of Rudolf Virchow in the 19th century that cancer-associated inflammation contributes to tumor onset and progression, involvement of the disruption of the balance between anti-tumor immunity via the immune surveillance system and pro-tumor immunity by cancer-associated inflammation in the malignant transformation of cancer remains elusive. Recently, the dysregulated expression and activation of representative RBPs involved in regulation of the production of pro-inflammatory cytokines have been shown to be involved in tumor progression. In this review, we summarize the recent progress in our understanding of the functional roles of these RBPs in several types of immune responses, and the involvement of RBP dysregulation in the pathogenesis of immune diseases and cancer, and discuss possible therapeutic strategies against cancer by targeting RBPs, coupled with immunotherapy.

[Research progress on the relationship between lncRNA and the pathogenesis of allergic rhinitis]

Long non-coding RNA（lncRNA） belongs to the category of non-coding RNA, which length exceeds 200 nucleotides and can hardly encode the expression of proteins. Based on the data from several clinical researches, it is considered that lncRNA not only plays the biological role in epigenetics, transcriptional and post-transcriptional levels, but also abnormally expresses in inflammatory response and the related diseases. In recent years, with the intensive study of gene expression regulation of allergic rhinitis（AR）, it has been found that a variety of non-coding RNA, including lncRNA, have close relationship with the occurrence and development of AR. This review mainly summarized the biological function, immunomodulatory effect of lncRNA and the relationship between the lncRNA and the pathogenesis of AR, providing new thoughts and strategies for the further research, prevention as well as the treatment of AR.

RNA regulatory mechanisms that control antiviral innate immunity

From the initial sensing of viral nucleotides by pattern recognition receptors, through the induction of type I and III interferons (IFN), upregulation of antiviral effector proteins, and resolution of the inflammatory response, each step of innate immune signaling is under tight control. Though innate immunity is often associated with broad regulation at the level of gene transcription, RNA-centric post-transcriptional processes have emerged as critical mechanisms for ensuring a proper antiviral response. Here, we explore the diverse RNA regulatory mechanisms that modulate the innate antiviral immune response, with a focus on RNA sensing by RIG-I-like receptors (RLR), interferon (IFN) and IFN signaling pathways, viral pathogenesis, and host genetic variation that contributes to these processes. We address the post-transcriptional interactions with RNA-binding proteins, non-coding RNAs, transcript elements, and modifications that control mRNA stability, as well as alternative splicing events that modulate the innate immune antiviral response.

An integrated analysis of lncRNA and mRNA expression profiles in the kidneys of mice with lupus nephritis

Long noncoding RNAs (lncRNAs) are persistently expressed and have been described as potential biomarkers and therapeutic targets in various diseases. However, there is limited information regarding lncRNA expression in the tissue of kidney exhibiting lupus nephritis (LN)a serious complication of systemic lupus erythematosus (SLE). In this study, RNA sequencing (RNA-seq) was performed to characterize the lncRNA and mRNA expression in kidney tissues from LN (MRL/lpr) and control mice. We identified 12,979 novel lncRNAs in mouse. The expression profiles of both mRNAs and lncRNAs were differed significantly between LN and control mice. In particular, there were more upregulated lncRNAs and mRNAs than downregulated ones in the kidney tissues of LN mice. However, GO analysis showed that more downregulated genes were enriched in immune and inflammatory response-associated pathways. KEGG analysis showed that both downregulated and upregulated genes were enriched in a number of pathways, including the SLE pathway, and approximately half of these SLE-associated genes encoded inflammatory factors. Moreover, we observed that 2,181 DElncRNAs may have targeted and regulated the expression of 778 mRNAs in LN kidney tissues. The results of this study showed that 11 DElncRNAs targeted and were co-expressed with six immune and SLE-associated genes. qPCR analysis confirmed that lncRNA Gm20513 positively regulated the expression of the SLE-associated gene H2-Aa. In conclusion, the results of our study demonstrates that lncRNAs influence the progression of LN and provide some cues for further study of lncRNAs in LN. These results regarding the lncRNA-mRNAregulatory network may have important value in LN diagnosis and therapy.

Plasmacytoid Dendritic Cell Infiltration in Acute Myeloid Leukemia

Introduction

Increasing evidence has demonstrated that plasmacytoid dendritic cells (PDCs) in the tumor microenvironment (TME) play an important role in tumorigenesis and progression. PDC infiltration has been found in certain malignancies such as classic Hodgkin’s lymphoma and chronic myelomonocytic leukemia. Our previous work reported that PDC infiltration could occur in acute myeloid leukemia (AML), but the clinical significance of PDC in AML has not been thoroughly investigated.

Patients and Methods

Here, we evaluated the clinical significance of PDC to AML transition in a leukemia microenvironment. The frequency of PDCs in 80 acute myelomonocytic leukemia (AML-M4) and 83 acute monocytic leukemia (AML-M5) patients was determined by flow cytometry.

Results

We found 62 cases with PDC infiltration. These patients showed higher numbers of bone marrow blasts, higher mean Hb concentration, and required more cycles of chemotherapy before achieving complete remission (CR), but had lower white blood cell and platelet counts compared to patients without PDC infiltration. Drug sensitivity analysis showed that patients with PDC infiltration had lower sensitivity to standard chemotherapy regimens. Kaplan–Meier survival curves demonstrated that patients with PDC infiltration had a shorter overall survival (OS) time and progression-free survival time.

Discussion

These results suggested that PDC infiltration can be used for risk stratification of AML-M4/M5, and PDCs may transdifferentiate into leukemia in an AML microenvironment.

LncRNAs in the Type I Interferon Antiviral Response

The proper functioning of the immune system requires a robust control over a delicate equilibrium between an ineffective response and immune overactivation. Poor responses to viral insults may lead to chronic or overwhelming infection, whereas unrestrained activation can cause autoimmune diseases and cancer. Control over the magnitude and duration of the antiviral immune response is exerted by a finely tuned positive or negative regulation at the DNA, RNA, and protein level of members of the type I interferon (IFN) signaling pathways and on the expression and activity of antiviral and proinflammatory factors. As summarized in this review, committed research during the last decade has shown that several of these processes are exquisitely regulated by long non-coding RNAs (lncRNAs), transcripts with poor coding capacity, but highly versatile functions. After infection, viruses, and the antiviral response they trigger, deregulate the expression of a subset of specific lncRNAs that function to promote or repress viral replication by inactivating or potentiating the antiviral response, respectively. These IFN-related lncRNAs are also highly tissue- and cell-type-specific, rendering them as promising biomarkers or therapeutic candidates to modulate specific stages of the antiviral immune response with fewer adverse effects.