Detection of PCV3 in German wild boars.

BACKGROUND: Porcine circovirus 3 is a newly described circovirus circulating worldwide. PCV3 may play an etiologic role in different pig diseases. Two different genotypes of PCV3 were described, PCV3a and PCV3b. In order to analyse whether PCV3 is also present in wild boars, animals living in and near Berlin were studied. The animals had been analysed previously and were found to form two genetically distinct and geographically coherent clusters. METHODS: To detect PCV3 in wild boars, a PCR was performed, to analyse the virus in detail, parts of the sequence of the capsid protein were sequenced. In addition, a screening for PCV1 and PCV2 was performed using PCR. RESULTS: For the first time, PCV3 was detected in German wild boars, with 50% of the animals infected in one genetic cluster, and 23% in the second cluster. In both populations which were divided in the years of division of Berlin, PCV3b was detected, in one case also PCV3a was detected. In some animals, co-infections with PCV1 and PCV2 or triple infections were detected. CONCLUSION: The data show a high prevalence of PCV3 and co-infections with PCV1 and PCV2 in German wild boars. The finding of PCV3 in both clusters suggests that the virus was introduced into the animal populations before Berlin was divided. Furthermore, the methods used will be indispensable for screening for circoviruses in pigs genetically modified for xenotransplantation.

Copy Number and Prevalence of Porcine Endogenous Retroviruses (PERVs) in German Wild Boars.

Porcine endogenous retroviruses (PERVs) are integrated in the genome of pigs and are transmitted like cellular genes from parents to the offspring. Whereas PERV-A and PERV-B are present in all pigs, PERV-C was found to be in many, but not all pigs. When PERV-C is present, recombination with PERV-A may happen and the PERV-A/C recombinants are characterized by a high replication rate. Until now, nothing has been known about the copy number of PERVs in wild boars and little is known about the prevalence of the phylogenetically youngest PERV-C in ancient wild boars. Here we investigated for the first time the copy number of PERVs in different populations of wild boars in and around Berlin using droplet digital PCR. Copy numbers between 3 and 69 per genome have been measured. A lower number but a higher variability was found compared to domestic pigs, including minipigs reported earlier (Fiebig et al., Xenotransplantation, 2018). The wild boar populations differed genetically and had been isolated during the existence of the Berlin wall. Despite this, the variations in copy number were larger in a single population compared to the differences between the populations. PERV-C was found in all 92 analyzed animals. Differences in the copy number of PERV in different organs of a single wild boar indicate that PERVs are also active in wild boars, replicating and infecting new cells as has been shown in domestic pigs.

Vitamin C promotes decitabine or azacytidine induced DNA hydroxymethylation and subsequent reactivation of the epigenetically silenced tumour suppressor CDKN1A in colon cancer cells.

Epigenetic silencing of tumour suppressor genes is a key hallmark of colorectal carcinogenesis. Despite this, the therapeutic potential of epigenetic agents capable of reactivating these silenced genes remains relatively unexplored. Evidence has shown the dietary antioxidant vitamin C (ascorbate) acts as an inducer of the ten-eleven translocation (TET) dioxygenases, an enzyme family that catalyses a recently described mechanism of DNA demethylation linked to gene re-expression. In this study, we set out to determine whether vitamin C can enhance the known anti-neoplastic actions of the DNA-demethylating agents decitabine (DAC) and azacytidine (AZA) in colorectal cancer cells. Administration of vitamin C alone significantly enhanced global levels of 5-hydroxymethyl-2'-deoxycytidine (5-hmdC), without altering 5-methyl-2'-deoxycytidine (5-mdC), as would be expected upon the activation of TET dioxygenases. Concomitant treatment of vitamin C with either AZA or DAC resulted in an unexpectedly high increase of global 5-hmdC levels, one that administration of any these compounds alone could not achieve. Notably, this was also accompanied by increased expression of the tumour suppressor p21 (CDKN1A), and a significant increase in apoptotic cell induction. Our in vitro data leads us to hypothesize that the reactivation of genes in colorectal cancer cells by AZA or DAC can be improved when the 5-hmdC levels are simultaneously increased by the TET activator vitamin C. The dual administration of demethylating agents and vitamin C to colorectal cancer patients, a demographic in which vitamin C deficiencies are common, may improve responses to epigenetic therapies.