KCNQ1OT1 contributes to sorafenib resistance and programmed death­ligand­1­mediated immune escape via sponging miR­506 in hepatocellular carcinoma cells.

Drug resistance and immune escape of tumor cells severely compromise the treatment efficiency of hepatocellular carcinoma (HCC). Long non­coding RNA KCNQ1 overlapping transcript 1 (lncRNA KCNQ1OT1) has been shown to be involved in drug resistance in several cancers. The aim of the present study was to investigate the role of KCNQ1OT1 in sorafenib resistance and immune escape of HCC cells. Reverse transcription­quantitative PCR analysis, western blotting and immunohistochemistry were performed to detect the expression of KCNQ1OT1, miR­506 and programmed death­ligand­1 (PD­L1). Cell Counting Kit­8 assay, flow cytometry and Transwell assays were used to evaluate IC50 value, cell apoptosis and metastasis. ELISA was performed to detect the secretion of cytokines. Dual­luciferase reporter assay was conducted to verify the targeting relationships between miR­506 and KCNQ1OT1 or PD­L1. KCNQ1OT1 and PD­L1 were found to be upregulated and miR­506 was downregulated in sorafenib­resistant HCC tissues and cells. Furthermore, KCNQ1OT1 knockdown reduced the IC50 value of sorafenib, suppressed cell metastasis and promoted apoptosis in sorafenib­resistant HCC cells. Moreover, KCNQ1OT1 knockdown changed the tumor microenvironment and T­cell apoptosis in a sorafenib­resistant HCC/T­cell co­culture model. In addition, it was demonstrated that KCNQ1OT1 functioned as a competing endogenous RNA of miR­506 and increased PD­L1 expression in sorafenib­resistant HCC cells. miR­506 inhibition abolished the effects of KCNQ1OT1 knockdown on sorafenib sensitivity, tumor growth, the tumor microenvironment and T­cell apoptosis. In conclusion, KCNQ1OT1 knockdown inhibited sorafenib resistance and PD­L1­mediated immune escape by sponging miR­506 in sorafenib­resistant HCC cells.

Subclade 2.2.1-Specific Human Monoclonal Antibodies That Recognize an Epitope in Antigenic Site A of Influenza A(H5) Virus HA Detected between 2015 and 2018.

Highly pathogenic avian H5 influenza viruses persist among poultry and wild birds throughout the world. They sometimes cause interspecies transmission between avian and mammalian hosts. H5 viruses possessing the HA of subclade 2.3.4.4, 2.3.2.1, 2.2.1, or 7.2 were detected between 2015 and 2018. To understand the neutralizing epitopes of H5-HA, we characterized 15 human monoclonal antibodies (mAbs) against the HA of H5 viruses, which were obtained from volunteers who received the H5N1 vaccine that contains a subclade 2.2.1 or 2.1.3.2 virus as an antigen. Twelve mAbs were specific for the HA of subclade 2.2.1, two mAbs were specific for the HA of subclade 2.1.3.2, and one mAb was specific for the HA of both. Of the 15 mAbs analyzed, nine, which were specific for the HA of subclade 2.2.1, and shared the VH and VL genes, possessed hemagglutination inhibition and neutralizing activities, whereas the others did not. A single amino acid substitution or insertion at positions 144-147 in antigenic site A conferred resistance against these nine mAbs to the subclade 2.2.1 viruses. The amino acids at positions 144-147 are highly conserved among subclade 2.2.1, but differ from those of other subclades. These results show that the neutralizing epitope including amino acids at positions 144-147 is targeted by human antibodies, and plays a role in the antigenic difference between subclade 2.2.1 and other subclades.

Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen.

BACKGROUND: Outbreaks caused by asexual lineages of fungal and oomycete pathogens are a continuing threat to crops, wild animals and natural ecosystems (Fisher MC, Henk DA, Briggs CJ, Brownstein JS, Madoff LC, McCraw SL, Gurr SJ, Nature 484:186-194, 2012; Kupferschmidt K, Science 337:636-638, 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl MF, Thomma BP, BioEssays 36:335-345, 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Goodwin SB, Cohen BA, Fry WE, Proc Natl Acad Sci USA 91:11591-11595, 1994; Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10:e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Cooke DEL, Cano LM, Raffaele S, Bain RA, Cooke LR, Etherington GJ, Deahl KL, Farrer RA, Gilroy EM, Goss EM, et al. PLoS Pathog 8:e1002940, 2012). However, the dynamics of genome evolution within these clonal lineages have not been determined. The objective of this study was to use a comparative genomics and transcriptomics approach to determine the molecular mechanisms that underpin phenotypic variation within a clonal lineage of P. infestans. RESULTS: Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by comparing strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Delgado RA, Monteros-Altamirano AR, Li Y, Visser RGF, van der Lee TAJ, Vosman B, Plant Pathol 62:1081-1088, 2013; Forbes GA, Escobar XC, Ayala CC, Revelo J, Ordonez ME, Fry BA, Doucett K, Fry WE, Phytopathology 87:375-380, 1997; Oyarzun PJ, Pozo A, Ordonez ME, Doucett K, Forbes GA, Phytopathology 88:265-271, 1998). We detected numerous examples of structural variation, nucleotide polymorphisms and loss of heterozygosity within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. CONCLUSIONS: Our findings highlight the molecular changes underpinning the exceptional genetic and phenotypic plasticity associated with host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen. We observed that the asexual P. infestans lineage EC-1 can exhibit phenotypic plasticity in the absence of apparent genetic mutations resulting in virulence on a potato carrying the Rpi-vnt1.1 gene. Such variant alleles may be epialleles that arose through epigenetic changes in the underlying genes.

Ébolavirus: biología molecular y evasión de la respuesta inmune / Ebolavirus: molecular biology and immune response evasion

La actual epidemia de enfermedad por virus Ébola que azota al África Occidental ha cobrado la vida de alrededor de 9 000 personas con más de 22 000 infectados en seis países, y algunos casos aislados han llegado a ciudades de Europa y Estados Unidos. Aunque el curso clínico de la enfermedad es bien conocido, los mecanismos específicos que explican su patogenicidad no han sido completamente delineados. Los casos fatales de infección por Ébolavirus están marcados por un fallo catastrófico de las respuestas inmune innata y adaptativa, mediado por proteínas codificadas por el virus, así como por propiedades asociadas a su estructura. El genoma del Ébolavirus está constituido solamente por siete genes que codifican unas 10 proteínas, suficientes para desencadenar una enfermedad cuya letalidad varía del 40 al 90 por ciento. En el centro de la desregulación inducida por el Ébola se encuentra una temprana y coordinada actuación de las proteínas VP24, VP30 y VP35, que conduce a niveles elevados de replicación viral, a una inapropiada temporización de la cascada de liberación de linfocinas y a la muerte, tanto de células presentadoras de antígenos, como de células efectoras. Los complejos mecanismos del Ébola para regular selectivamente la respuesta inmune y su patogenicidad variable en diferentes especies hospederas, convierten a este virus en un adversario formidable, así como de un notable interés científico(AU)

The current Ebolavirus disease outbreak that strikes West Africa has claimed the life of around 9 000 people and has infected more than 22 000 in six countries, and some isolated cases have reached cities of Europe and the United States. Though the clinical course of the disease is well known, the specific mechanisms of its pathogenicity have not been fully delineated yet. Fatal cases of Ebolavirus disease are marked by a catastrophic failure of both innate and adaptive immune responses, mediated by virus-encoded proteins as well as properties associated with its structure. Ebolavirus genome comprises only seven genes encoding about 10 proteins, enough to cause a disease which fatality fluctuates from 40 to 90 percent. At the heart of Ebola-induced immune dysregulation is an early and coordinated disruption by VP24, VP30, and VP35 that leads to elevated levels of virus replication, a cascade of inappropriately timed cytokine release, and death of both antigen-presenting and responding immune cells. The complex mechanisms of Ebola to selectively regulate immune responses and its variable pathogenicity in different host species makes this virus both, a challenging foe and scientifically interesting(AU)

Effect of Chinese medicine therapy for strengthening-Pi and nourishing-Shen in preventing lamivudine induced YMDD mutation and its immunologic mechanism.

OBJECTIVE: To observe the effect of Chinese medicine therapy for strengthening-Pi and nourishing-Shen (SPNS) in preventing lamivudine induced YMDD mutation and its immunological mechanism. METHODS: One hundred and sixty chronic hepatitis B (CHB) patients with positive HBeAg were equally assigned to two groups at random: the observation group and the control group. Patients in the observation group were treated with lamivudine combined with SPNS, and those in the control group were treated with lamivudine only, with the treatment lasting for 52 weeks in total. Changes in indexes, including liver function, HbeAg, HBV-DNA, YMDD variation, CD(4), CD(4)/CD(8) ratio, interferon-gamma (IFN-gamma), interleukin-4 (IL-4), blood routine, renal function, as well as any adverse reactions that occurred in patients, were observed at different time points. RESULTS: The ALT, AST recovery rate and HBV-DNA negatively inversing rate at the 24th week, the 36th week and the 52nd week were all higher (P<0.05); meanwhile, the YMDD mutation rate at the 36th week and the 52nd week was lower (P<0.05) in the observation group than in the control group. The posttreatment levels of CD(4), CD(4)/CD(8) ratio, IFN-gamma, and IL-4 as well as the pre-post treatment difference of these indexes in the observation group were significantly different from those in the control group (P<0.05). CONCLUSION: Chinese medicine SPNS therapy can significantly reduce the YMDD variation of HBV, and the mechanism may be related to its regulation of the CD(4) level, CD(4)/CD(8) ratio and Th1/Th2 balance.