scholarly journals A nuclear import pathway exploited by pathogenic noncoding RNAs

2021 ◽  
Author(s):  
Junfei Ma ◽  
Shachinthaka D. Dissanayaka Mudiyanselage ◽  
Woong June Park ◽  
Mo Wang ◽  
Ryuta Takeda ◽  
...  

AbstractThe prevailing view regarding intracellular RNA trafficking in eukaryotic cells describes that RNAs transcribed in the nucleus either stay in the nucleus or cross the nuclear envelope entering the cytoplasm for function. Interestingly, emerging evidence illustrates numerous functional RNAs trafficking in the reverse direction from the cytoplasm to the nucleus. However, the mechanism underlying the RNA nuclear import has not been well elucidated. Viroids are single-stranded circular noncoding RNAs that infect plants. Using nuclear-replicating viroids as a model, we showed that cellular Importin alpha-4 is likely involved in viroid RNA nuclear import, empirically supporting the involvement of Importin-based cellular pathway in RNA nuclear import. We also confirmed the involvement of a cellular protein (Virp1) that binds both Importin alpha-4 and viroids. Furthermore, a conserved C-loop in nuclear-replicating viroids is critical for Virp1 binding. Disrupting C-loop impairs Virp1 binding, viroid nuclear accumulation and infectivity. Further, C-loop exists in a subviral satellite noncoding RNA that relies on Virp1 for nuclear import. These results have significant implications for understanding the infection process of subviral agents. In addition, our data outline a cellular pathway responsible for the nuclear import of RNAs and uncover a 3-dimensional RNA motif-based regulation over RNA nuclear import.

2020 ◽  
Vol 8 (12) ◽  
pp. 2044
Author(s):  
Hyesu Seo ◽  
Ying Wang ◽  
Woong June Park

Viroids are single-stranded noncoding RNA molecules of 250–400 nucleotides that cause plant diseases. One of the two families of viroids is Pospiviroidae, the members of which replicate in the nuclei of host cells. To replicate in plants, viroids of Pospiviroidae must enter the nucleus. However, the nuclear import of viroids remains understudied. In this work, we documented the time-dependent characteristics of the changes in microinjected fluorescently labeled potato spindle tuber viroid (PSTVd). The cytoplasmic fluorescence disappeared gradually, with only nuclear fluorescence remaining as the PSTVd injected in the cytoplasm was imported into the nucleus. Through this work, we determined that the time for half-maximal nuclear accumulation of the viroid was about 23 min. Interestingly, we found some cells where the nuclear import did not occur, despite the high level of cytosolic viroid injected. In some cells, the injected viroids disappeared within 10–20 min. The nuclear import of PSTVd is not a simple concentration-dependent process but was probably under the regulation of diverse factors that may be missing from some cells used for our observation.


2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
F. P. Fabrizio ◽  
A. Sparaneo ◽  
D. Trombetta ◽  
L. A. Muscarella

Oxidative and electrophilic changes in cells are mainly coordinated by the KEAP1/NRF2 (Kelch-like erythroid-derived cap-n-collar homology- (ECH-) associated protein-1/nuclear factor (erythroid-derived 2)-like 2) axis. The physical interaction between these two proteins promotes the expression of several antioxidant defense genes in response to exogenous and endogenous insults. Recent studies demonstrated that KEAP1/NRF2 axis dysfunction is also strongly related to tumor progression and chemo- and radiotherapy resistance of cancer cells. In solid tumors, the KEAP1/NRF2 system is constitutively activated by the loss ofKEAP1or gain ofNFE2L2functions that leads to its nuclear accumulation and enhances the transcription of many cytoprotective genes. In addition to point mutations, epigenetic abnormalities, as aberrant promoter methylation, and microRNA (miRNA) and long noncoding RNA (lncRNA) deregulation were reported as emerging mechanisms of KEAP1/NRF2 axis modulation. This review will summarize the current knowledge about the epigenetic mechanisms that deregulate the KEAP1/NRF2 cascade in solid tumors and their potential usefulness as prognostic and predictive molecular markers.


2005 ◽  
Vol 25 (8) ◽  
pp. 3087-3108 ◽  
Author(s):  
Wei Hu ◽  
Alana S. Philips ◽  
Juliana C. Kwok ◽  
Michael Eisbacher ◽  
Beng H. Chong

ABSTRACT The Ets factor Friend leukemia integration 1 (Fli-1) is an important regulator of megakaryocytic (Mk) differentiation. Here, we demonstrate two novel nuclear localization signals (NLSs) within Fli-1: one (NLS1) is located at the N terminus, and another (NLS2) is within the Ets domain. Nuclear accumulation of Fli-1 reflected the combined functional effects of the two discrete NLSs. Each NLS can independently direct nuclear transport of a carrier protein, with mutations within the NLSs affecting nuclear accumulation. NLS1 has a bipartite motif, whereas the NLS2 region contains a nonclassical NLS. Both NLSs bind importin alpha (IMPα) and IMPβ, with NLS1 and NLS2 being predominantly recognized by IMPα and IMPβ, respectively. Fli-1 also contains one nuclear export signal. Leptomycin B abolished its cytoplasmic accumulation, showing CRM1 dependency. We demonstrate that Ets domain binding to specific target DNA effectively blocks IMP binding, indicating that the targeted DNA binding plays a role in localizing Fli-1 to its destination and releasing IMPs for recycling back to the cytoplasm. Finally, by analyzing full-length Fli-1 carrying NLS1, NLS2, and combined NLS1-NLS2 mutations, we conclude that two functional NLSs exist in Fli-1 and that each NLS is sufficient to target Fli-1 to the nucleus for activation of Mk-specific genes.


Oncogene ◽  
2021 ◽  
Vol 40 (17) ◽  
pp. 3164-3179
Author(s):  
Yang Liu ◽  
Tianchi Tang ◽  
Xiaosheng Yang ◽  
Peng Qin ◽  
Pusen Wang ◽  
...  

AbstractPancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies and rapidly progressive diseases. Exosomes and long noncoding RNAs (lncRNAs) are emerging as vital mediators in tumor cells and their microenvironment. However, the detailed roles and mechanisms of exosomal lncRNAs in PDAC progression remain unknown. Here, we aimed to clarify the clinical significance and mechanisms of exosomal lncRNA 01133 (LINC01133) in PDAC. We analyzed the expression of LINC01133 in PDAC and found that exosomal LINC01133 expression was high and positively correlated with higher TNM stage and poor overall survival rate of PDAC patients. Further research demonstrated that Periostin could increase exosome secretion and then enhance LINC01133 expression. In addition, Periostin increased p-EGFR, p-Erk, and c-myc expression, and c-myc could bind to the LINC01133 promoter region. These findings suggested that LINC01133 can be regulated by Periostin via EGFR pathway activity. We also observed that LINC01133 promoted the proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) of pancreatic cancer cells. We subsequently evaluated the effect of LINC01133 on the Wnt/β-catenin pathway and confirmed that LINC01133 can interact with Enhancer Of Zeste Homolog 2 (EZH2) and then promote H3K27 trimethylation. This can further silence AXIN2 and suppress GSK3 activity, ultimately activating β-catenin. Collectively, these data indicate that exosomal LINC01133 plays an important role in pancreatic tumor progression, and targeting LINC01133 may provide a potential treatment strategy for PDAC.


2018 ◽  
Vol 18 (6) ◽  
pp. 538-557 ◽  
Author(s):  
Soraya Sajadimajd ◽  
Mozafar Khazaei

Oxidative stress due to imbalance between ROS production and detoxification plays a pivotal role in determining cell fate. In response to the excessive ROS, apoptotic signaling pathway is activated to promote normal cell death. However, through deregulation of biomolecules, high amount of ROS promotes carcinogenesis in cells with defective signaling factors. In this line, NRF2 appears to be as a master regulator, which protects cells from oxidative and electrophilic stress. Nrf2 is an intracellular transcription factor that regulates the expression of a number of genes to encode anti-oxidative enzymes, detoxifying factors, anti-apoptotic proteins and drug transporters. Under normal condition, Nrf2 is commonly degraded in cytoplasm by interaction with Keap1 inhibitor as an adaptor for ubiquitination factors. However, high amount of ROS activates tyrosine kinases to dissociate Nrf2: Keap1 complex, nuclear import of Nrf2 and coordinated activation of cytoprotective gene expression. Nevertheless, deregulation of Nrf2 and/or Keap1 due to mutation and activated upstream oncogenes is associated with nuclear accumulation and constitutive activation of Nrf2 to protect cells from apoptosis and induce proliferation, metastasis and chemoresistance. Owning to the interplay of ROS and Nrf2 signaling pathways with carcinogenesis, Nrf2 modulation seems to be important in the personalization of cancer therapy.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 251.1-251
Author(s):  
J. M. Kim ◽  
H. J. Kang ◽  
S. J. Jung ◽  
B. W. Song ◽  
H. J. Jeong ◽  
...  

Background:Long noncoding RNAs (lncRNAs) have recently emerged as important biological regulators and the aberrant expression of lncRNAs has been reported in various diseases including cancer, cardiovascular disease, and diabetes mellitus. However, the role of lncRNAs in the pathogenesis of rheumatoid arthritis (RA) remains unknown.Objectives:Thus, we studied lncRNAs influenced by IL-1, which is one of the key mediators in the pathogenesis of RA, and also investigated whether regulation of NF-κB activation, which is known to be induced by IL-1, could lead to the changes of expression of those lncRNAs.Methods:Fibroblast-like synoviocytes (FLS) were obtained from the knee joints of the patients with RA. The next-generation sequencing (NGS) data were analyzed to identify differentially expressed lncRNAs between unstimulated RA FLS and IL-1-stimulated RA FLS. The expression levels of the top 5 candidates in NGS data were validated by RT-qPCR using extended number of unstimulated RA FLS and IL-1-stimulated RA FLS. IMD-0560, an inhibitor of IκB kinase (IKK) was used for the regulation of NF-κB activation. Activation and inhibition of NF-κB were confirmed by Western blotting. Changed expressions of the lncRNAs were identified by RT-qPCR.Results:NGS analysis revealed up-regulated 30 lncRNAs and down-regulated 15 lncRNAs in IL-1-treated RA FLS compared with unstimulated RA FLS. Top 5 lncRNAs were selected among 30 lncRNAs up-regulated by IL-1 in RA FLS based on fold-change with P-value cutoff. The up-regulated lncRNAs including NR_046035, NR_027783, NR_033422, NR_003133, and NR_049759 were validated by RT-qPCR. IMD-0560 inhibited phosphorylation of IκBα induced by IL-1 in RA FLS. Overexpression of lncRNAs induced by IL-1 was also inhibited by IMD-0560 in RA FLS.Conclusion:Our study revealed that IL-1 increased the expression of NR_046035, NR_027783, NR_033422, NR_003133, and NR_049759 in RA FLS. In addition, the expression of these lncRNAs was regulated by inhibition of NF-κB activation. Thus, our data suggest that the lncRNAs might be involved in the pathogenesis of RA through NF-κB signaling pathway.References:[1]Long noncoding RNAs and human disease. Trends Cell Biol. 2011 Jun;21(6):354-61.[2]A long noncoding RNA mediates both activation and repression of immune response genes. Science. 2013 Aug 16;341(6147):789-92.[3]Long noncoding RNA expression profile in fibroblast-like synoviocytes from patients with rheumatoid arthritis. Arthritis Res Ther. 2016 Oct 6;18(1):227.Disclosure of Interests:None declared


2018 ◽  
Vol 39 (01) ◽  
pp. 013-025 ◽  
Author(s):  
Massimiliano Salati ◽  
Chiara Braconi

AbstractCholangiocarcinomas (CCAs) are tumors with a dismal prognosis. Early diagnosis is a key challenge because of the lack of specific symptoms, and the curability rate is low due to the difficulty in achieving a radical resection and the intrinsic chemoresistance of CCA cells. Noncoding RNAs (ncRNAs) are transcripts that are not translated into proteins but exert their functional role by regulating the transcription and translation of other genes. The discovery of the first ncRNA dates back to 1993 when the microRNA (miRNA) lin-4 was discovered in Caenorhabditis elegans. Only 10 years later, miRNAs were shown to play an oncogenic role in cancer cells and within 20 years miRNA therapeutics were tested in humans. Here, the authors review the latest evidence for a role for ncRNAs in CCA and discuss the promise and challenges associated with the introduction of ncRNAs into clinical practice.


2017 ◽  
Vol 216 (11) ◽  
pp. 3497-3507 ◽  
Author(s):  
Ronald L Neppl ◽  
Chia-Ling Wu ◽  
Kenneth Walsh

Skeletal muscle exhibits remarkable plasticity in its ability to modulate its mass in response to the physiologic changes associated with functional use, systemic disease, and aging. Although a gradual loss of muscle mass normally occurs with advancing age, its increasingly rapid progression results in sarcopenia in a subset of individuals. The identities of muscle-enriched, long noncoding RNAs that regulate this process are unknown. Here, we identify a long noncoding RNA, named Chronos, whose expression in muscle is positively regulated with advancing age and negatively regulated during Akt1-mediated growth. Inhibition of Chronos induces myofiber hypertrophy both in vitro and in vivo, in part, through the epigenetic modulation of Bmp7 signaling.


Author(s):  
Wei Wang ◽  
Ni Yang ◽  
Ri Wen ◽  
Chun-Feng Liu ◽  
Tie-Ning Zhang

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection and is characterized by a hyperinflammatory state accompanied by immunosuppression. Long noncoding RNAs (lncRNAs) are noncoding RNAs longer than 200 nucleotides and have important roles in mediating various biological processes. Recently, lncRNAs were found to exert both promotive and inhibitory immune functions in sepsis, thus participating in sepsis regulation. Additionally, several studies have revealed that lncRNAs are involved in sepsis-induced organ dysfunctions, including cardiovascular dysfunction, acute lung injury, and acute kidney injury. Considering the lack of effective biomarkers for early identification and specific treatment for sepsis, lncRNAs may be promising biomarkers and even targets for sepsis therapies. This review systematically highlights the recent advances regarding the roles of lncRNAs in sepsis and sheds light on their use as potential biomarkers and treatment targets for sepsis.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yan Zhang ◽  
Xianwu Chen ◽  
Juntao Lin ◽  
Xiaodong Jin

AbstractBladder cancer (BCa) is one of the 10 most common cancers with high morbidity and mortality worldwide. Long noncoding RNAs (lncRNAs), a large class of noncoding RNA transcripts, consist of more than 200 nucleotides and play a significant role in the regulation of molecular interactions and cellular pathways during the occurrence and development of various cancers. In recent years, with the rapid advancement of high-throughput gene sequencing technology, several differentially expressed lncRNAs have been discovered in BCa, and their functions have been proven to have an impact on BCa development, such as cell growth and proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and drug-resistance. Furthermore, evidence suggests that lncRNAs are significantly associated with BCa patients’ clinicopathological characteristics, especially tumor grade, TNM stage, and clinical progression stage. In addition, lncRNAs have the potential to more accurately predict BCa patient prognosis, suggesting their potential as diagnostic and prognostic biomarkers for BCa patients in the future. In this review, we briefly summarize and discuss recent research progress on BCa-associated lncRNAs, while focusing on their biological functions and mechanisms, clinical significance, and targeted therapy in BCa oncogenesis and malignant progression.


Sign in / Sign up

Export Citation Format

Share Document