A comprehensive method protocol for annotation and integrated functional understanding of lncRNAs

Long noncoding RNA protein-disulfide isomerase-associated 3 regulated high glucose-induced podocyte apoptosis in diabetic nephropathy through targeting miR-139-3p

BACKGROUND

Podocyte apoptosis plays a vital role in proteinuria pathogenesis in diabetic nephropathy (DN). The regulatory relationship between long noncoding RNAs (lncRNAs) and podocyte apoptosis has recently become another research hot spot in the DN field.

AIM

To investigate whether lncRNA protein-disulfide isomerase-associated 3 (Pdia3) could regulate podocyte apoptosis through miR-139-3p and revealed the underlying mechanism.

METHODS

Using normal glucose or high glucose (HG)-cultured podocytes, the cellular functions and exact mechanisms underlying the regulatory effects of lncRNA Pdia3 on podocyte apoptosis and endoplasmic reticulum stress (ERS) were explored. LncRNA Pdia3 and miR-139-3p expression were measured through quantitative real-time polymerase chain reaction. Relative cell viability was detected through the cell counting kit-8 colorimetric assay. The podocyte apoptosis rate in each group was measured through flow cytometry. The interaction between lncRNA Pdia3 and miR-139-3p was examined through the dual luciferase reporter assay. Finally, western blotting was performed to detect the effect of lncRNA Pdia3 on podocyte apoptosis and ERS via miR-139-3p.

RESULTS

The expression of lncRNA Pdia3 was significantly downregulated in HG-cultured podocytes. Next, lncRNA Pdia3 was involved in HG-induced podocyte apoptosis. Furthermore, the dual luciferase reporter assay confirmed the direct interaction between lncRNA Pdia3 and miR-139-3p. LncRNA Pdia3 overexpression attenuated podocyte apoptosis and ERS through miR-139-3p in HG-cultured podocytes.

CONCLUSION

Taken together, this study demonstrated that lncRNA Pdia3 overexpression could attenuate HG-induced podocyte apoptosis and ERS by acting as a competing endogenous RNA of miR-139-3p, which might provide a potential therapeutic target for DN.

m6A-mediated lncRNA MAPKAPK5-AS1 induces apoptosis and suppresses inflammation via regulating miR-146a-3p/SIRT1/NF-κB axis in rheumatoid arthritis

To investigate the role of m6A-mediated lncRNA MAPKAPK5-AS1 (MK5-AS1) in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) and its underlying molecular mechanism. RT-qPCR, western blot, flow cytometry (FCM), and enzyme-linked immunosorbent assay (ELISA) were utilized for evaluating inflammation and apoptosis. Next, RIP, RNA pull-down, dual-luciferase reporter gene assay, and a series of rescue experiments were performed to explore the regulatory mechanisms of MK5-AS1 and its sponge-like action in RA-FLSs. The regulatory relationships between MK5-AS1 and WTAP were explored using the MeRIP-qPCR assay and RT-qPCR. Finally, the critical RNAs in the ceRNA axis were verified in the clinical cohort. MK5-AS1 was poorly expressed and miR-146a-3p was overexpressed in co-cultured RA-FLSs. MK5-AS1 overexpression could inhibit inflammatory responses and promote cell apoptosis in the co-cultured RA-FLSs. MK5-AS1 bound to miR-146a-3p to target SIRT1, thereby affecting inflammatory responses and cell apoptosis in the co-cultured RA-FLSs. SIRT1 knockdown or miR-146a-3p overexpression reversed the impacts of MK5-AS1 overexpression on co-cultured RA-FLSs inflammation and apoptosis. Moreover, WTAP was downregulated, and induced the inhibition of MK5-AS1 by promoting its RNA transcript stability. Clinically, MK5-AS1 was downregulated in RA-PBMCS and correlated with the clinical characteristics of RA. Our study elucidated that m6A-mediated MK5-AS1 sequestered miR-146a-3p to suppress SIRT1 expression in co-cultured RA-FLSs, thus providing a new insight into the treatment of rheumatoid arthritis.

Long non-coding RNAs in oncourology

For several decades, research in tumor biology has focused on the involvement of genes encoding a protein. Only recently has it been discovered that a whole class of molecules called non-coding RNAs (ncRNAs) play a key regulatory role in health and disease. Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs longer than 200 nucleotides. It has been found that lncRNAs play a fundamental role in the biology of many types of tumors, including tumors of the genitourinary system. As a result, hundreds of clinical trials dedicated to oncourology have begun, using lncRNA as new biomarkers or treatments. Identifying new specific biomarkers, in the form of lncRNAs, will increase the ability to differentiate the tumor and other processes, determine the localization and extent of the tumor, and the ability to predict the course of the disease, and plan treatment. Therapy of tumors, especially malignant ones, is also a difficult task. When surgery and chemotherapy fail, radiation therapy becomes the treatment choice. Therefore, the possibility that lncRNAs could represent innovative therapeutic agents or targets is an exciting idea. However, the possibility of their use in modern clinical practice is limited, and this is associated with several problems at the pre-, analytical and post-analytical stages. Another problem in the study of lncRNAs is the large number and variety of their functions in tumors. Therefore, solving technological problems in lncRNAs study in oncourology may open up new possibilities for lncRNAs use in modern clinical practice.

Genome-wide analysis of lncRNA stability in human

Transcript stability is associated with many biological processes, and the factors affecting mRNA stability have been extensively studied. However, little is known about the features related to human long noncoding RNA (lncRNA) stability. By inhibiting transcription and collecting samples in 10 time points, genome-wide RNA-seq studies was performed in human lung adenocarcinoma cells (A549) and RNA half-life datasets were constructed. The following observations were obtained. First, the half-life distributions of both lncRNAs and messanger RNAs (mRNAs) with one exon (lnc-human1 and m-human1) were significantly different from those of both lncRNAs and mRNAs with more than one exon (lnc-human2 and m-human2). Furthermore, some factors such as full-length transcript secondary structures played a contrary role in lnc-human1 and m-human2. Second, through the half-life comparisons of nucleus- and cytoplasm-specific and common lncRNAs and mRNAs, lncRNAs (mRNAs) in the nucleus were found to be less stable than those in the cytoplasm, which was derived from transcripts themselves rather than cellular location. Third, kmers-based protein−RNA or RNA−RNA interactions promoted lncRNA stability from lnc-human1 and decreased mRNA stability from m-human2 with high probability. Finally, through applying deep learning−based regression, a non-linear relationship was found to exist between the half-lives of lncRNAs (mRNAs) and related factors. The present study established lncRNA and mRNA half-life regulation networks in the A549 cell line and shed new light on the degradation behaviors of both lncRNAs and mRNAs.

Transcript stability is important for many biological processes. However, little is known about the features related to human lncRNA stability. Through quantitative analysis between the half-lives of lncRNAs (mRNAs) and various factors, we found a nonlinear relationship between the half-lives of lncRNAs (mRNAs) and the related factors and their combinations. Our research provided a comprehensive understanding of lncRNA stability. Further efforts are needed to develop an accurate quantitative prediction model for the half-lives of lncRNA (mRNA).