Changes in MicroRNA Expression during Rabbit Hemorrhagic Disease Virus (RHDV) Infection.

Current knowledge on the role of microRNAs (miRNAs) in rabbit hemorrhagic disease virus (RHDV) infection and the pathogenesis of rabbit hemorrhagic disease (RHD) is still limited. RHDV replicates in the liver, causing hepatic necrosis and liver failure. MiRNAs are a class of short RNA molecules, and their expression profiles vary over the course of diseases, both in the tissue environment and in the bloodstream. This paper evaluates the expression of miRNAs in the liver tissue (ocu-miR-122-5p, ocu-miR-155-5p, and ocu-miR-16b-5p) and serum (ocu-miR-122-5p) of rabbits experimentally infected with RHDV. The expression levels of ocu-miR-122-5p, ocu-miR-155-5p, and ocu-miR-16b-5p in liver tissue were determined using reverse transcription quantitative real-time PCR (RT-qPCR), and the expression level of circulating ocu-miR-122-5p was established using droplet digital PCR (ddPCR). The expression levels of ocu-miR-155-5p and ocu-miR-16b-5p were significantly higher in the infected rabbits compared to the healthy rabbits (a fold-change of 5.8 and 2.5, respectively). The expression of ocu-miR-122-5p was not significantly di�erent in the liver tissue from the infected rabbits compared to the healthy rabbits (p = 0.990), while the absolute expression level of the circulating ocu-miR-122-5p was significantly higher in the infected rabbits than in the healthy rabbits (p < 0.0001). Furthermore, a functional analysis showed that ocu-miR-155-5p, ocu-miR-16b-5p, and ocu-miR-122-5p can regulate the expression of genes involved in processes correlated with acute liver failure (ALF) in rabbits. Search tool for the retrieval of interacting genes/proteins (STRING) analysis showed that the potential target genes of the three selected miRNAs may interact with each other in di�erent pathways. The results indicate the roles of these miRNAs in RHDV infection and over the course of RHD and may reflect hepatic inflammation and impairment/dysfunction in RHD

Changes in innate and adaptive immune response to Lagovirus europaeus GI.1 (Rabbit Haemorrhagic Disease Virus -RHDV) infection

Lagovirus europaeus GI.1 (Rabbit Haemorrhagic Disease Virus – RHDV) is a virus that causes rabbit haemorrhagic disease (RHD) that affects domestic and wild rabbits worldwide. Due to the fact that the impact of RHDV on the host organism, and more precisely, its influence on the immune system, is crucial for the spread of this infection in rabbits, it is very important to understand the role of the immune system components in the course of infection with this virus. The aim of the study was to present innate and adaptive immune response to three strains (V411, 1092V, Wika) of the Lagovirus europaeus GI.1 (RHDV) identified at different times. Twelve indices were examined for the innate immune response and nine for the adaptive response. The results indicate that PMN cells (polymorphonuclear cells, neutrophils) play an important role in the response to this infection and give new insights into the function of CD4+ Th and CD8+ Tc lymphocytes. The most immunogenic was the Wika strain from 1996.Lagovirus europaeus GI.1 (Rabbit Haemorrhagic Disease Virus – RHDV) infekuje króliki domowe i dzikie na całym świecie, wywołując u nich krwotoczną chorobę królików (RHD-rabbit haemorrhagic disese). Z uwagi na fakt, że wpływ RHDV na organizm żywiciela, a dokładniej jego wpływ na układ odpornościowy, ma kluczowe znaczenie dla rozprzestrzeniania się tej infekcji u królików, bardzo ważne jest poznanie roli elementów układu odpornościowego w przebiegu zakażenia tym wirusem. Dlatego też celem badań było przedstawienie zmian we wrodzonej i nabytej odpowiedzi immunologicznej po zakażeniu trzema szczepami (V411, 1092V, Wika) Lagovirus europaeus GI.1 (RHDV), zidentyfikowanymi w różnym czasie. W za-kresie wrodzonej odpowiedzi immunologicznej zbadano dwanaście wskaźników, a w nabytej dziewięć. Uzyskane rezultaty wskazują na udział komórek PMN (polimorfonuklearnych, neu-trofilii) jako ważnych elementów w odpowiedzi na to zakażenie oraz rzucają nowe spojrzenie na udział limfocytów CD4+ Th i CD8+ Tc. Najbardziej immunogenny okazał się szczepem Wika z 1996 r

Vimentin as a Cap of Invisibility: Proposed Role of Vimentin in Rabbit Hemorrhagic Disease Virus (RHDV) Infection

Vimentin is an intermediate filament, a cytoskeleton protein expressed mainly in cells of mesenchymal origin. Increasing evidence indicates that vimentin could play a key role in viral infections. Therefore, changes in tissue and extracellular vimentin expression and associated signal trails may determine/protect the fate of cells and the progression of disease caused by viral infection. Rabbit hemorrhagic disease virus (RHDV), genotype GI.1, is an etiological agent that causes a severe and highly lethal disease—RHD (rabbit hemorrhagic disease). This article evaluates the gene and protein expression of vimentin in the tissues (liver, lungs, spleen, and kidneys) and serum of rabbits experimentally infected with two RHDV variants (GI.1a). The VIM mRNA expression levels in the tissues were determined using reverse transcription quantitative real-time PCR (RT-qPCR). In addition, the amount of vimentin protein in the serum was analyzed by an ELISA test. We observed significantly elevated expression levels of VIM mRNA and protein in the liver and kidney tissues of infected rather than healthy rabbits. In addition, VIM mRNA expression was increased in the lung tissues; meanwhile, we observed only protein-enhanced vimentin in the spleen. The obtained results are significant and promising, as they indicate the role of vimentin in RHDV infection and the course of RHD. The role of vimentin in RHDV infection could potentially rely on the one hand, on creating a cap of invisibility against the intracellular viral spread, or, on the other hand, after the damage of cells, vimentin could act as a signal of tissue damage

MicroRNAs as new immunity regulators in viral and bacterial infections

MicroRNAs (miRNAs) – small, conserved RNA molecules, containing 22 to 25 nucleotides and occurring in the cells of living organisms. As regulatory molecules, they have enormous biological potential and can influence a number of cellular processes. In the context of immunology, the role of miRNAs as novel immunity regulators is invaluable. The miRNAs regulate immune phenomena at many levels - starting from the impact on the processes of maturation, proliferation and differentiation of the immune system cells, through the regulation of the secretion of their products, to the regulation of intracellular signalling pathways. In all these areas, the miRNAs can play the role of both an inducer and an inhibitor by appropriately increasing the intensity of or suppressing the immune processes they regulate. In the future, it will be possible to regulate the host’s immune response to the pathogen thanks to the properly controlled expression of miRNAs in the immune system cells.MikroRNA (miRNA), małe, konserwatywne 22–25 nukleotydowe cząsteczki RNA występujące powszechnie w komórkach żywych organizmów. Jako cząsteczki regulatorowe mają ogromny potencjał biologiczny i mogą wypływać na wiele procesów komórkowych. W kontekście immunologii nieoceniona jest rola miRNA jako nowych regulatorów odporności. MiRNA regulują zjawiska odpornościowe na wielu poziomach. Począwszy od wpływu na procesy dojrzewania, proliferacji oraz różnicowania komórek układu odpornościowego, przez regulację wydzielania ich produktów, po regulację wewnątrzkomórkowych szlaków sygnalizacyjnych. Na wszystkich tych polach miRNA może odgrywać rolę zarówno induktora, jak i inhibitora, odpowiednio zwiększając nasilenie lub wygaszając regulowane przez siebie procesy odpornościowe. W przyszłości dzięki właściwie pokierowanej ekspresji miRNA w komórkach układu odpornościowego możliwe będzie regulowanie przebiegu odpowiedzi immunologicznej gospodarza w odpowiedzi na patogen

New Insights into the Role of the Complement System in Human Viral Diseases

The complement system (CS) is part of the human immune system, consisting of more than 30 proteins that play a vital role in the protection against various pathogens and diseases, including viral diseases. Activated via three pathways, the classical pathway (CP), the lectin pathway (LP), and the alternative pathway (AP), the complement system leads to the formation of a membrane attack complex (MAC) that disrupts the membrane of target cells, leading to cell lysis and death. Due to the increasing number of reports on its role in viral diseases, which may have implications for research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), this review aims to highlight significant progress in understanding and defining the role of the complement system in four groups of diseases of viral etiology: (1) respiratory diseases; (2) acute liver failure (ALF); (3) disseminated intravascular coagulation (DIC); and (4) vector-borne diseases (VBDs). Some of these diseases already present a serious global health problem, while others are a matter of concern and require the collaboration of relevant national services and scientists with the World Health Organization (WHO) to avoid their spread

Genetic variation and phylogenetic analysis of rabbit haemorrhagic disease virus (rhdv) strains

Rabbit haemorrhagic disease virus (RHDV) belongs to the family Caliciviridae and is the etiological agent of the haemorrhagic disease, also known as rabbit plague. Its genome is a linear single-stranded (ss) RNA of 7437 nucleotides and the capsid is built from a single structural protein VP60. In connection with the discovery of new RHDV strains, there is a constant need to investigate the genetic variation of this virus and perform phylogenetic analyses which may show the evolutionary relationships among the RHDV strains. Studies on the divergence of RHDV have shown that it is genetically quite stable, although recent observations indicate that some new RHDV strains, significantly different from the original RHDV subtype and the new RHDVa subtype, are appearing. These latest findings suggest that a new group of RHDV strains has evolved. The present review summarizes the current knowledge on the genetic variation and the latest achievements in phylogenetic analyses of RHDV strains isolated in various countries

MicroRNAs participate in the regulation of apoptosis and oxidative stress-related gene expression in rabbits infected with Lagovirus europaeus GI.1 and GI.2 genotypes

MicroRNAs (miRs) are a group of small, 17–25 nucleotide, non-coding RNA that regulate gene expression at the post-transcriptional level. To date, little is known about the molecular signatures of regulatory interactions between miRs and apoptosis and oxidative stress in viral diseases. Lagovirus europaeus is a virus that causes severe disease in rabbits (Oryctolagus cuniculus) called Rabbit Hemorrhagic Disease (RHD) and belongs to the Caliciviridae family, Lagovirus genus. Within Lagovirus europaeus associated with RHD, two genotypes (GI.1 and GI.2) have been distinguished, and the GI.1 genotype includes four variants (GI.1a, GI.1b, GI.1c, and GI.1d). The study aimed to assess the expression of miRs and their target genes involved in apoptosis and oxidative stress, as well as their potential impact on the pathways during Lagovirus europaeus—two genotypes (GI.1 and GI.2) infection of different virulences in four tissues (liver, lung, kidneys, and spleen). The expression of miRs and target genes related to apoptosis and oxidative stress was determined using quantitative real-time PCR (qPCR). In this study, we evaluated the expression of miR-21 (PTEN, PDCD4), miR-16b (Bcl-2, CXCL10), miR-34a (p53, SIRT1), and miRs—related to oxidative stress—miR-122 (Bach1) and miR-132 (Nfr-2). We also examined the biomarkers of both processes (Bax, Bax/Bcl-2 ratio, Caspase-3, PARP) and HO-I as biomarkers of oxidative stress. Our report is the first to present the regulatory effects of miRs on apoptosis and oxidative stress genes in rabbit infection with Lagovirus europaeus—two genotypes (GI.1 and GI.2) in four tissues (liver, lungs, kidneys, and spleen). The regulatory effect of miRs indicates that, on the one hand, miRs can intensify apoptosis (miR-16b, miR-34a) in the examined organs in response to a viral stimulus and, on the other hand, inhibit (miR-21), which in both cases may be a determinant of the pathogenesis of RHD and tissue damage. Biomarkers of the Bax and Bax/Bcl-2 ratio promote more intense apoptosis after infection with the Lagovirus europaeus GI.2 genotype. Our findings demonstrate that miR-122 and miR-132 regulate oxidative stress in the pathogenesis of RHD, which is associated with tissue damage. The HO-1 biomarker in the course of rabbit hemorrhagic disease indicates oxidative tissue damage. Our findings show that miR-21, miR-16b, and miR-34a regulate three apoptosis pathways. Meanwhile, miR-122 and miR-132 are involved in two oxidative stress pathways

Apoptosis of peripheral blood leucocytes in rabbits infected with different strains of rabbit haemorrhagic disease virus

The pathogenicity of RHDV (rabbit haemorrhagic disease virus) is mainly associated with its affinity to blood vessels, with causing disseminated intravascular coagulations (DIC), and with the stimulation of the host immune system. Moreover, there are implications suggesting that apoptosis may be a pivotal process in understanding the basis of viral haemorrhagic disease in rabbits - a serious infectious disease causing mortality to wild and domestic rabbits. The aim of this study is to evaluate, by means of flow cytometry, the dynamics of apoptosis in peripheral blood granulocytes and lymphocytes in rabbits experimentally infected with seven different strains of RHDV and so-called antigenic variants of RHDV denominated as RHDVa, i.e.: Hungarian 24V/89, 1447V/96, 72V/2003; Austrian 01-04, 237/04, V-412 and French 05-01. The results showed that all of the RHDV and RHDVa strains cause an increase in the number of apoptotic cells throughout the infection, which might indicate the need for further analysis of the importance of this process