Expression of NF45 in laryngeal squamous cell carcinoma and its effect on radiation sensitivity of tumor cells / 中华放射肿瘤学杂志

Objective:To investigate the expression of double-stranded RNA-binding protein nuclear factor 45 (NF45) in laryngeal squamous cell carcinoma (LSCC), and the effect of NF45 on the radiation sensitivity of LSCC cells and its mechanism.Methods:NF45 expression in LSCC and adjacent tissues was detected by real-time reverse transcription PCR (qRT-PCR) and immunohistochemical staining. The NF45-ShRNA lentivirus was transfected into Hep-2 cells, and cell transfection efficiency was determined by qRT-PCR and Western blot . Hep-2 cells were randomly divided into the control group, 2 Gy group, sh-NC+2 Gy group and sh-NF45+2 Gy group. Lentivirus infection and 2Gy X-ray irradiation treatment were carried out. Cell proliferation activity was assessed by CCK-8 assay. Apoptosis rate was determined by flow cytometry. Hep-2 cells in each group were treated with mCherry-EGFP-LC3B. The levels of autophagy were detected by immunofluorescence staining. The ratio of autophagy-related protein microtubule-associated protein 1 light chain 3 (LC3)-Ⅱ/LC3-Ⅰ and the expression levels of Beclin-1 and p62 proteins were determined by Western blot.Results:The expression level of NF45 in LSCC tissues was significantly higher than that in adjacent tissues ( P<0.01). The relative expression levels of NF45 mRNA and protein in Hep-2 cells infected with NF45-shRNA were significantly lower than those in the control and sh-NC groups (all P<0.05). Compared with the control group, the cell proliferation activity was decreased, the apoptosis rate was increased, the intracellular autophagy-lysosome were increased, the ratio of LC3-Ⅱ/LC3-Ⅰ was increased, the relative expression levels of Beclin-1 protein were up-regulated, and the relative expression levels of p62 protein were down-regulated in the 2 Gy, sh-NC+2 Gy and sh-NF45+2 Gy groups (all P<0.05). Compared with the 2 Gy group, the cell proliferation activity was decreased, the apoptosis rate was increased, the intracellular autophagy lysosomes were increased, the LC3-Ⅱ/LC3-Ⅰ ratio was increased, the relative expression of Beclin-1 protein was up-regulated, and the relative expression of p62 protein was down-regulated in the sh-NF45+2 Gy group (all P<0.05). Conclusions:The expression of NF45 is up-regulated in LSCC tissues. Targeted down-regulation of NF45 expression can inhibit the proliferation activity of LSCC cells, promote cell apoptosis, and improve the sensitivity of tumor cells to radiation. The mechanism may be related to the regulation of autophagy levels.

Post-transcriptional gene silencing: Basic concepts and applications

Post-transcriptional gene silencing (PTGS)-mediated gene silencing exploits the cellular mechanism whereintranscripts having sequence similarity to the double-stranded RNA (dsRNA) molecules present in the cell will besubjected to degradation. PTGS is closely related to natural processes such as RNA-mediated virus resistance andcross-protection in plants. Gene silencing and the cellular machinery for affecting this phenomenon might haveevolved as a natural protective measure against viral infection in plants. In PTGS, small interfering RNA (siRNA)molecules of 21–23 nucleotides length act as homology guides for triggering the systemic degradation of transcriptshomologous to the siRNA molecules. PTGS phenomenon, first discovered in transgenic petunia plants harbouringchalcone synthase gene and termed co-suppression, has been subsequently exploited to target specific gene transcripts for degradation leading to manifestation of desirable traits in crop plants. Targeted gene silencing has beenachieved either through the introduction of DNA constructs encoding dsRNA or antisense RNA or by deploying cosuppression constructs producing siRNAs against the transcript of interest. Understanding the mechanism of genesilencing has led to the development of several alternative strategies for inducing gene silencing in a precise andcontrolled way. This has paved the way for using PTGS as one ofthe chief functional genomicstools in plants and hashelped in unraveling the mechanism of many cellular processes and identifying the focal points in pathways, besides,opening new vistas in genetic engineering of plants for human benefits. PTGS has shown great potential in silencingthe deleterious genes efficiently so that value-added plant products could be obtained. Thus, PTGS has ushered in anew era in the genetic manipulation of plants for both applied and basic studies. In this review, we have outlined thebasics of RNAi-mediated gene silencing and summarized the work carried out at our institute using this approach, ascase studies. In particular, adopting RNAi-mediated gene silencing (a) as a method to restore fertility in transgenicmale sterile lines developed based on orfH522 gene from sunflower PET1-CMS source, (b) as a tool to suppress theproduction of toxic proteins, ricin and RCA, in castor, and (c) as an approach to induce bud necrosis virus resistancein sunflower has been discussed. Examples from other plant systems also have been mentioned to exemplify theconcept and utility of gene silencing in crop plants.

Function and Characterization of the Argonaute2 Gene in the RNA Interference Pathway in the Diamondback Moth

Arch BiochemMol Biol2019;10(4):035-051DOI: 10.26502/abmb.007Archives of Biochemistry and Molecular BiologyVol. 10 No. 4 -December2019. 36AbstractArgonaute2 (AGO2) is a core catalytic component of the RNA-induces silencing complex (RISC) that binds to small guide RNAs containing small interfering RNA (siRNA) and microRNA (miRNA). The guide RNA leads RISC to the complementary mRNA for gene suppression. We cloned the full length cDNA (2193 bp) of the Ago2gene (PxAgo2) from diamondback moth (DBM, Plutella xylostella). The predicted PxAgo2 protein hadan83 kDa molecular weight withatheoretical isoelectric point of 9.39. The phylogenetic tree showed a high similarity of PxAgo2with Bombyx moriAgo2 (BmAgo2). Western blot and RT-qPCR analyses showed a clear increase in the PxAgo2 mRNA and protein expression levels in the egg, 4thinstar larva, pre-pupa, pupa and adult. The double-stranded RNA-mediated RNAi of PxAgo2in DBM larvae was found 3 h after dsRNA injection,and the knockdown level was increased over time up to 36 h. PxAgo2silencing recovered the expression of PxBurs-?(Bursicon-? inDBM) to the normal expression level, which was suppressed bydsPxBurs-?in a DBM cell line. The overexpression of PxAgo2fundamentally enhanced the PxBurs-? silencing efficiency in DBM cells. Our findings reveal that PxAgo2is involved in the dsRNA-regulated gene silencing mechanism and performs a crucial function in the RNAi process ofDBM

Mechanism of migration and release of high mobility group box-1 / 中南大学学报(医学版)

High mobility group box-1 (HMGB1) is an evolutionarily conserved protein,which widely exists in mammals.HMGB 1 contains the nucleus localization sequences.Intracellular and extracellular HMGB1 shows different biological functions.Extracellular HMGB1 is closely related to sepsis,cancer,rheumatoid immune,atherosclerosis,ischemia-reperfusion injury and so on.The mobilization of HMGB 1 from the nucleus to the cytoplasm and subsequent release involves the processes of post-translation modification,active secretion and nuclear localization.

PKR as a Regulator of Inflammasome Activation

Detection of pathogen by pattern recognition receptors leads to activation of inflammasome which plays a crucial role in immune system. The inflammasome regulates the release of cytokines, such as interleukin (IL)-1beta, IL-18 and high-mobility group box 1 (HMGB1). Double-stranded RNA-dependent protein kinase (PKR) is a critical component of an inflammatory complex. Recently, the critical role of PKR was reported in regulation of multiple inflammasomes.

MicroARNs: una visión molecular / MicroRNA (miRNA): A molecular view

Los microARNs son ARN pequeños de aproximadamente 22 nucleótidos de longitud que participan en la regulación de muchos procesos celulares y, su alteración está asociada con el desarrollo de diferentes patologías, especialmente cáncer. Gracias al uso de las herramientas de bioinformática es posible determinar su distribución en el genoma y sus funciones en diferentes tejidos. La mayoría de microARNs son producidos en una vía canónica a partir de un transcripto primario largo, en un proceso secuencial de dos reacciones guiadas principalmente por dos enzimas, Drosha en el núcleo y Dicer en el citoplasma. Sin embargo, actualmente han sido descritas algunas vías no canónicas de generación de microARNs. El objetivo de esta revisión es describir el proceso de generación de microARNs y la maquinaria involucrada en su generación con el propósito de lograr alcanzar un mejor entendimiento de los diferentes procesos en los cuales están involucrados. Salud UIS 2011; 43 (3): 289-297.

MicroRNAs are small RNAs of approximately 22 nucleotides in length that participate in the regulation of many cellular processes and it alteration is associated with the development of different pathologies in particular, cancer. Using bioinformatics tools is possible determine their wide distribution in the genome and their functions in different tissues. Mostly of microRNAs are produced in a canonical way from a long primary transcript, in a sequential process of two reactions guided mostly by two enzymes: Drosha in the nucleus and Dicer in the cytoplasm. However, it has been described some pathways non-canonical for the generation of microRNAs. The aim of this review is to describe the generation process of microRNAs and the machinery involved in their generation for the purpose of achieving a better understanding of the different processes they are involved. Salud UIS 2011; 43 (3): 289-297.

The presence of dsRNA virus in Trichomonas vaginalis isolates from symptomatic and asymptomatic Indian women and its correlation with in vitro metronidazole sensitivity.

Purpose: Trichomonas vaginalis, a protozoan parasite, is the causative agent of human trichomoniasis, the most common non-viral sexually transmitted disease. The infection encompasses from a complete asymptomatic presentation to severe sequelae; yet, the virulence markers have been poorly understood. It is suggested that the presence of Trichomonas vaginalis virus (TVV) in T. vaginalis may have an impact on its virulence, and its relatedness to in vitro metronidazole resistance has been reported. The aim of the study was to assess the presence of TVV in fresh and Long -Term Cultivated ( LTC) maintained T. vaginalis isolates from symptomatic (S) and asymptomatic (AS) Indian women and its relatedness, if any, with symptomatology and in vitro drug sensitivity. Materials and Methods: One thousand women (537 S and 463 AS) were screened for the presence of T. vaginalis by wet smear and culture examination of vaginal swab and urine sample. Fresh and LTC (6 months-2 years) maintained 15 isolates each from 15 S and 15 AS women were subjected to agarose gel electrophoresis following total cellular RNA extraction to evaluate the presence of double stranded (ds) RNA viral infection. The susceptibility of isolates to metronidazole was determined in vitro. Results: On agarose gel electrophoresis, three bands (5.5, 2.5 and 1.5 kb) were observed in all the 30 fresh isolates from 15 S and 15 AS women and only in 7 LTC isolates from 3 S and 4 AS women. All the fresh isolates harbouring TVV were found to be sensitive to metronidazole in vitro irrespective of the symptomatology of subjects, and out of seven LTC isolates harbouring TVV, six were sensitive to metronidazole and one showed borderline resistance. Conclusions: The results suggest that the presence of TVV alone may not be a virulence marker and loss of TVV on LTC appears to be related to drug resistance. The T. vaginalis Indian isolates are sensitive to metronidazole.

Establishment and application of a tandem affinity purification system of innate immune regulatory protein PKR / 中华微生物学和免疫学杂志

Objective To establish a tandem affinity purification(TAP) system of innate immune-regulatory protein PKR and analyze PKR function, for the future screen and identification of novel PKR-interaction proteins. Methods PKR gene was amplified by PCR, and then cloned into a mammalian expression vector pcTAP-A. Recombinant pcTAP-PKR was transfected into PKR knock-down(PKRkd) HeLa cells by LipofectAMINE 2000,and the PKR overexpressed HeLa cells were harvested for mitogen-activated protein kinases(MAPK) activation analysis. Cell extracts of PKR overexpressed cells were purified using TAP kit and examined by Western blot. Results Cal modulin resin(CBP) and streptavidin resin(SBP) tagged PKR was detected in PKRkd HeLa cells as early as 24 h upon transfection with pcTAP-PKR, and its expression decreased at later time points. The overexpression of PKR was autophosphorylated, and thus involved in the regulation of MAPK actviation. After small-scale TAP kit purification, PKR protein was detectable by Western blot. Conclusion We have successfully established a TAP system that over-expresses functional PKR, providing a useful tool for the future study on the identification of PKR interacting proteins.

Grandes alcances de los RNAs pequeños RNA de interferencia y microRNA / Great potential of small RNas: RNA interference and microRNA

Double-stranded RNA (dsRNA) induces a sequence-specific silencing in eukaryotic cells. This silencing process beggins when long dsRNA is cleaved to 21 to 26 long small RNA by means of the RNAse III-type enzyme Dicer. These small dsRNA are included into silencing effector complexes, that are targeted to complementary sequences. Small RNA dependent gene silencing can be achieved by distinct mechanisms based depending mainly on the nature of target sequences and on the proteins present in the effector complex. The route of interference RNA (RNAi) begins when Dicer yields small interference RNA (siR-NA) that bind to complementary mRNA for its degradation, forming the RISC complex. siRNA are naturally formed from transposons and dsRNA viruses during its replication, as well as from other bidirectional transcribed repetitive sequences. Some of the enzymes thar are part of the RNAi machinery, including Dicer, are encoded by multigene families in many species, that also play a role in other mechanisms of RND-dependent gene silencing. MicroRNA's (miRNA) are other small RNA's that can induce gene silencing at the mRNA level. These are formed in a general manner when Dicer process hairpin structures resulting from the transcription of non-coding sequences from plant and animal genomes. miRNA's are integrated into a RISC-like complex, after which, depending on their degree of complementarity with target mRNA, can either repress translation or induce mRNA degradation. miRNA-dependent silencing is essential for the development of multicellular organisms. Artificial RNAi induction by means of siRNA or miRNA is being used as a tool to inactivate gene expression in culture cells and in living organisms. This review focuses on the progress in the understanding of the mechanisms involved in gene regulation by RNA in animals and details some current efforts to apply theses phenomena as a tool in research and in the therapeutic of human diseases.

El RNA de doble cadena puede inducir un silenciamiento secuencia-específico en eucarionte. Este proceso de silenciamiento se inicia cuando el RNAdc largo es procesado a RNA pequeño de 21 a 26 nucleótidos mediante la enzima RNAsa III Dicer. Estos RNA pequeños se incorporan a complejos efectores de silenciamiento, que son guiados a secuencias complementarias blanco. Existen diferentes tipos de silenciamiento, cuyas diferencias se basan principalmente en la naturaleza de la secuencia blanco y en la composición proteica de los complejos efectores. La ruta del RNA de interferencia (RNAi) se inicia cuando Dicer genera pequeños RNA de interferencia (siRNA) que se unen por complementariedad al mRNA para su degradación, utilizando el complejo RISC. De manera natural, los siRNA se originan de transposones y virus que producen RNAdc durante su replicación, así como también de otras secuencias repetidas transcritas bidireccionalmente. Algunas de las enzimas que conforman la maquinaria del RNAi como Dicer, entre otras, son codificadas por familias multigénicas en varias especies y también participan en otros mecanismos de silenciamiento mediado por RNA. Los microRNA son otros RNA pequeños que pueden inducir silenciamiento al unirse al mRNA. Éstos se generan de manera general cuando Dicer procesa estructuras de horquilla compuestas de regiones no codificantes, en genomas de plantas y animales. Los miRNA se incorporan a un complejo similar a RISC y, dependiendo de su grado de complementariedad con el mRNA blanco, pueden tener represión traduccional o bien digerir el mRNA. El silenciamiento mediado por miRNA es esencial para el desarrollo de plantas y animales. La inducción artificial del RNAi mediante siRNA o miRNA ha sido adoptada como una herramienta para inactivar la expresión génica, tanto en células en cultivo como en organismos vivos. En esta revisión se muestra el gran progreso en el entendimiento de los mecanismos que participan en la regulación génica mediada por RNA en animales y detalla algunos esfuerzos actuales para encauzar a estos mecanismos como una herramienta en la investigación y como posible terapia en enfermedades.