PIWI/piRNA-mediated regulation of signaling pathways in cell apoptosis.

OBJECTIVE: This study aims to summarize the role of PIWIs/piRNAs in cell apoptosis through multiple signaling pathways. The PIWI-interacting RNAs (piRNAs) are among the small non-coding RNAs (sncRNAs) and are mainly expressed in germline cells. PIWI protein is the key to the biogenesis of piRNA. With the deepening of research in recent years, the PIWIs/piRNAs are expressed in a tissue-specific way in somatic cells outside the germline. In addition, researchers have found that the PIWIs/piRNAs play a regulatory role in cell apoptosis, proliferation, and necrosis by regulating key signaling pathways, such as PI3K/Akt signaling pathway, STAT signaling pathway, TGF-ß signaling pathway, and Fas signaling pathway at the transcriptional or post-transcriptional level. However, the PIWIs/piRNAs' role in cell apoptosis and its underlying mechanisms are still not fully understood. This study reviews the regulatory functions of PIWIs/piRNAs in apoptosis from the perspective of the signal pathway. MATERIALS AND METHODS: This study is a narrative review. PubMed and MEDLINE were used as the primary sources to search the following keywords: PIWI/piRNAs, signal pathway, pro-apoptotic, anti-apoptotic, and signaling pathway. RESULTS: PIWIs/piRNAs modulated pro-apoptotic or anti-apoptotic effects in a variety of cells: PIWIs/piRNAs through PI3K/Akt signaling pathway, STAT signaling pathway, TGF-ß signaling pathway, and Fas signaling pathway for pro-apoptotic or anti-apoptotic effects in cells. CONCLUSIONS: Apoptosis is a basic biological phenomenon of cell death, and it also has a great significance and complex molecular biological mechanisms. PIWI/piRNAs are closely related to various types of diseases and play a pro-apoptotic or anti-apoptotic role through the following pathways: PI3K/Akt signaling, STAT signaling, TGF-ß signaling, and Fas signaling pathways.

[Mechanism of Mycobacterium tuberculosis on interleukin-6 receptor 3'-untranslated region methylation in CD4+T cells].

Objective: To investigate the role and mechanism of DNA methylation in Mycobacterium tuberculosis (MTB lysate) -induced downregulation of interleukin-6 receptor(IL-6R) expression in CD4+T cells. Methods: A prospective study was conducted. Bisulfite sequencing (BSP) was applied to determine the methylation levels of CpG island in IL-6R promoter region and 3'untranslated region (3'UTR) region in CD4+T cells from peripheral blood mononuclear cells (PBMC) of control group (healthy person, n=10) and TB group (tuberculosis patients, n=10) in Shenzhen Third People's Hospital between 2019 and 2020. Quantitative reverse transcription-PCR (RT-qPCR) and Western blotting were used to detect the expression of IL-6R, DNMT1, DNMT3A and DNMT3B in MTB lysate-stimulated CD4+T cells and Jurkat E6-1 cells. Furthermore, PBMC in control group and Jurkat E6-1 cells activated by anti-CD3/CD28 antibody were stimulated by MTB lysates to detect the methylation levels of CpG island and IL-6R and DNMT expression. Transcriptional activity of differently methylation regions of IL-6R 3'UTR was detected by using luciferase reporter gene system. Results: IL-6R expression in TB group was lower than that in control group, but DNMT1 and DNMT3B expressions were higher than those in control group in CD4+T cells isolated from PBMC. There was no significant difference in the methylation rate of IL-6R promoter CpG island of CD4+T cells between control and TB group. However, the methylation rates of CpG island in 3'UTR region were significantly higher (P<0.001) in TB (69.5%±3.4%), compared with control (54.3%±4.7%). Besides, IL-6R expression was lower than unstimulated, while DNMT1 and DNMT3B expression was higher than unstimulated after MTB lysate-stimulation of activated control PBMC in vitro. The methylation rate of CpG island in IL-6R 3'UTR region of CD4+T cells increased from 58.8%±11.6% to 79.4%±10.9% (P<0.001) after MTB lysate-stimulated PBMC of the control. The same results were observed in the MTB lysate-stimulated CD4+T cells isolated from PBMC in control and Jurkat E6-1 cell line. Furthermore, IL-6R expression after co-treatment of the DNA methyltransferase inhibitor decitabine (5-aza) with MTB lysate was higher than that stimulated by MTB lysate alone. In addition, the methylation levels of CpG islands in the 3' UTR region of IL-6R were lower than those stimulated by MTB lysates alone after co-treatment of the DNA methyltransferase inhibitor decitabine (5-aza) with MTB lysates. The transcriptional activity of the fully unmethylated IL-6R 3'UTR CpG island reporter gene was higher than that of the fully methylated IL-6R 3'UTR CpG island. Conclusions: MTB lysates stimulation inhibited IL-6R expression transcriptionalely as well as on the protein level by inducing hypermethylation of CpG island in IL-6R 3'UTR region of CD4+T cells. The hypermethylation of CpG island in IL-6R 3'UTR region of CD4+T cells induced by MTB may be related to the increased expression of DNMT1 and DNMT3B.

Generation of a velogenic Newcastle disease virus from cDNA and expression of the green fluorescent protein.

Newcastle disease virus (NDV) is a pathogen that is important in the poultry industry worldwide. Specifically, the virulent (velogenic) NDV is a particular threat because it has now occurred frequently worldwide. The outbreaks caused by highly virulent NDV in waterfowl and especially in goose flocks, have led to greater concern in recent years as aquatic birds were previously resistant to most virulent NDV strains from chickens. The molecular determinants of host tropism, virulence and emergence of NDV isolated from diseased goose flocks are poorly understood. In the present study, we rescued a highly virulent NDV isolated from a goose using the reverse genetics approach. Infectious virus was successfully generated by cotransfection of a full-length cDNA clone of the NDV strain ZJ1 with helper plasmids. The recombinant NDV was indistinguishable from the parental wild-type virus with respect to its growth kinetics in cell culture as well as its biological properties. A recombinant NDV expressing green fluorescent protein (GFP) was generated, and GFP was subsequently detected in cells and various organs from the infected chickens.

Genomic sequence of an isolate of Newcastle disease virus isolated from an outbreak in geese: a novel six nucleotide insertion in the non-coding region of the nucleoprotein gene. Brief Report.

We have completely sequenced the genome of an isolate of Newcastle disease virus (NDV) obtained following an outbreak in geese. The genomic sequence consists of 15192 nt, which is six nt longer than the published full length genome of the NDV strains La Sota, B1, Clone-30, Beaudette C and HB V4. The six nt insertion was located in the non-coding region of the nucleoprotein (NP) gene between nt 1646 and nt 1647 of the NDV genome (numbered according to the genomic sequence of the La Sota strain). An additional 22 NDV strains were searched for the existence of this six nt insertion. NDVs in genotypes VI, VII, VIII and IX had this insertion while NDV's in genotypes I, II, III, IV, and V did not. The significance of this insertion in NDV evolution is discussed.

Pathotypical and genotypical characterization of strains of Newcastle disease virus isolated from outbreaks in chicken and goose flocks in some regions of China during 1985-2001.

Twenty-nine strains of Newcastle disease virus (NDV) isolated from outbreaks in chicken and goose flocks in several regions of China during 1985-2001 were characterized pathotypically and genotypically. All except one of these strains were velogenic. For genotyping, phylogenetic tree analysis (nt 47-420), restriction site mapping (nt 334-1682) and residue substitution analysis (residues 4-124) of the F gene were performed using sequences of our isolates and sequences of selected NDV strains from GenBank. The results revealed that most of these newly characterized strains belonged to six novel genetic groups that were designated as VIf, VIg, VIIc, VIId, VIIe and IX. The genotype IX viruses, to which the China challenge strain F48E8 used for vaccine evaluation belonged, were found only in China and still induced sporadic infections in certain areas. Isolates belonging to group VIf and VIg were distinct from previously reported members of genotype VI, with genetic distance from 2.5 to 12.1%. Subgenotype VIIc, VIId and VIIe viruses, which were distributed in clusters in the phylogenetic tree distinct from members of subgenotypes VIIa and VIIb, were responsible for disease outbreaks in chicken and goose flocks and circulated predominantly in southern China in recent years. Finally, cross-protective testing showed that specific-pathogen free (SPF) chickens vaccinated with La Sota vaccines can be fully protected against challenge by strains from genetic groups VIb, VIg, VIId and IX, indicating that the antigenic differences between strains of various genotypes are insufficient to change the cross-protection conferred by the commonly used vaccine.