Consequences of Both Coxsackievirus B4 and Type 1 Diabetes on Female Non-Obese Diabetic Mouse Kidneys

Despite the 2019 Executive Order on Advancing American Kidney Health Initiative, kidney disease has moved up in rank from the 9th to the 8th leading cause of death in the United States. A recent push in the field of nephrology has been to identify molecular markers and/or molecular profiles involved in kidney disease process or injury that can help identify the cause of injury and predict patient outcomes. While these studies have had moderate success, they have not yet considered that many of the health conditions that cause kidney disease (diabetes, hypertension, etc.) can also be caused by environmental factors (such as viruses), which in and of themselves can cause kidney disease. Thus, the goal of this study was to identify molecular and phenotypic profiles that can differentiate kidney injury caused by diabetes (a health condition resulting in kidney disease) and coxsackievirus B4 (CVB4) exposure (which can cause diabetes and/or kidney disease), both alone and together. Non-obese diabetic (NOD) mice were used for this study due to their susceptibility to both type 1 diabetes (T1D)- and CVB4-mediated kidney injury, in order to glean a better understanding of how hyperglycemia and viral exposure, when occurring on their own and in combination, may alter the kidneys’ molecular and phenotypic profiles. While no changes in kidney function were observed, molecular biomarkers of kidney injury were significantly up- and downregulated based on T1D and CVB4 exposure, both alone and together, but not in a predictable pattern. By combining individual biomarkers with function and phenotypic measurements (i.e., urinary albumin creatinine ratio, serum creatinine, kidney weight, and body weight), we were able to perform an unbiased separation of injury group based on the type of injury. This study provides evidence that unique kidney injury profiles within a kidney disease health condition are identifiable, and will help us to identify the causes of kidney injury in the future.

Genetic diversity of enteroviruses in patients with respiratory infection

Enterovirus genetic variability underlies the variety of clinical forms of diseases they cause. The aim of the presented study was to establish the genetic diversity of enteroviruses (EVs) that caused acute respiratory infection (ARI) in 2016–2019. Biological samples were obtained from 203 patients with various forms of ARI, EV detection was carried out by RT-PCR, followed by sequencing of the main capsid protein gene and phylogenetic reconstruction. EV RNA was detected in 34.4 % of samples, most often in children aged 1–6 years (53.1–54.8 %). Coxsackieviruses B were found in patients with respiratory enterovirus infection (EVI) significantly more often than other EVs, the dominant serotypes were Coxsackievirus B4, B5. Despite the significant genetic diversity of EVs identified in patients with ARI (three genetic lines of Coxsackievirus B5, two genotypes of Coxsackievirus B2, one genotype of Coxsackievirus B3, three genovariant Coxsackievirus B4, one genovariant Coxsackievirus B1), there is no evidence of their connection with the formation of the respiratory form of EVI.The high level of genetic variability of EVs requires regular molecular-epidemiological surveillance for the identification of emerging genetic variants and assessment of their epidemic potential.

Coxsackievirus B4 Transplacental Infection Severely Disturbs Central Tolerogenic Mechanisms in the Fetal Thymus

Thymus plays a fundamental role in central tolerance establishment, especially during fetal life, through the generation of self-tolerant T cells. This process consists in T cells education by presenting them tissue-restricted autoantigens promiscuously expressed by thymic epithelial cells (TECs), thus preventing autoimmunity. Thymus infection by Coxsackievirus B (CV-B) during fetal life is supposed to disturb thymic functions and, hence, to be an inducing or accelerating factor in the genesis of autoimmunity. To further investigate this hypothesis, in our current study, we analyzed thymic expression of autoantigens, at the transcriptional and protein level, following in utero infection by CV-B4. mRNA expression levels of Igf2 and Myo7, major autoantigens of pancreas and heart, respectively, were analyzed in whole thymus and in enriched TECs together along with both transcription factors, Aire and Fezf2, involved in autoantigens expression in the thymus. Results show that in utero infection by CV-B4 induces a significant decrease in Igf2 and Myo7 expression at both mRNA and protein level in whole thymus and in enriched TECs as well. Moreover, a correlation between viral load and autoantigens expression can be observed in the whole thymus, indicating a direct effect of in utero infection by CV-B4 on autoantigens expression. Together, these results indicate that an in utero infection of the thymus by CV-B4 may interfere with self-tolerance establishment in TECs by decreasing autoantigen expression at both mRNA and protein level and thereby increase the risk of autoimmunity onset.

Effect of Coxsackievirus B4 Infection on the Thymus: Elucidating Its Role in the Pathogenesis of Type 1 Diabetes

The thymus gland is a primary lymphoid organ for T-cell development. Various viral infections can result in disturbance of thymic functions. Medullary thymic epithelial cells (mTECs) are important for the negative selection of self-reactive T-cells to ensure central tolerance. Insulin-like growth factor 2 (IGF2) is the dominant self-peptide of the insulin family expressed in mTECs and plays a crucial role in the intra-thymic programing of central tolerance to insulin-secreting islet β-cells. Coxsackievirus B4 (CVB4) can infect and persist in the thymus of humans and mice, thus hampering the T-cell maturation and differentiation process. The modulation of IGF2 expression and protein synthesis during a CVB4 infection has been observed in vitro and in vivo in mouse models. The effect of CVB4 infections on human and mouse fetal thymus has been studied in vitro. Moreover, following the inoculation of CVB4 in pregnant mice, the thymic function in the fetus and offspring was disturbed. A defect in the intra-thymic expression of self-peptides by mTECs may be triggered by CVB4. The effects of viral infections, especially CVB4 infection, on thymic cells and functions and their possible role in the pathogenesis of type 1 diabetes (T1D) are presented.

Persistence of Coxsackievirus B4 in Pancreatic β Cells Disturbs Insulin Maturation, Pattern of Cellular Proteins, and DNA Methylation

Coxsackievirus-B4 (CV-B4) can persist in pancreatic cell lines and impair the phenoytpe and/or gene expressions in these cells; however, the models used to study this phenomenon did not produce insulin. Therefore, we investigated CV-B4 persistence and its consequences in insulin-producing pancreatic β cells. The insulin-secreting rat β cell line, INS-1, was infected with CV-B4. After lysis of a large part of the cell layer, the culture was still maintained and no additional cytopathic effect was observed. The amount of insulin in supernatants of cell cultures persistently infected with CV-B4 was not affected by the infection; in fact, a larger quantity of proinsulin was found. The mRNA expression of pro-hormone convertase 2, an enzyme involved in the maturation of proinsulin into insulin and studied using real-time reverse transcription-polymerase chain reaction, was inhibited in infected cultures. Further, the pattern of 47 cell proteins analyzed using Shotgun mass spectrometry was significantly modified. The DNA of persistently infected cell cultures was hypermethylated unlike that of controls. The persistent infection of INS-1 cells with CV-B4 had a deep impact on these cells, especially on insulin metabolism. Cellular changes caused by persistent CV-B4 infection of β cells can play a role in type 1 diabetes pathogenesis.

Epidemiological aspects of enterovirus infection in the Russian Federation during the period of 2018–2019

Aim: Analysis of enterovirus infection morbidity and characteristics of the etiological agents of this infection on some territories of Russia in 2017.Materials and methods: We investigated 7858 samples of the biological material from the patients suffering from enterovirus infection. The isolation and identification of enteroviruses were conducted by virological and molecular methods.Results: The epidemic process and the clinical picture of enterovirus infection on different territories had some peculiarities. On some territories enterovirus meningitis was the predominant form of infection, on other territories enterovirus infection with exanthema prevailed. In Saint-Petersburg, Archangel and Saratov regions the percentage of enterovirus infection cases with the clinical picture of enterovirus meningitis was significantly higher than the percentage of enterovirus infection with exanthema. In the Komi Republic, Leningrad and Murmansk regions the percentage of infection with exanthema was statistically higher than the enterovirus meningitis portion. Enteroviruses of 30 serotypes were detected in the samples of patients suffering from enterovirus infection. We determined the etiology of sporadic and epidemic cases of enterovirus infection represented by different clinical forms. On some territories the epidemic foci of enterovirus infection among children were revealed. The etiological agents of enterovirus meningitis foci in Saint-Petersburg, Murmansk and Saratov regions were Coxsackievirus B5, Coxsackievirus B4 and Echovirus 30. The foci of enterovirus infection with exanthema in Archangel, Leningrad, Murmansk and Novgorod regions were caused by Coxsackieviruses A10, A16 and A6.Conclusion: The clinical forms of enterovirus infection on some territories were provoked by enteroviruses which dominated in the circulation on one or other territory. Enteroviruses of species B, mainly Echovirus 30, Echovirus 6 and Coxsackieviruses B1–6 were the etiological agents of enterovirus meningitis. The etiological factors of enterovirus infection with exanthema were Enteroviruses of species A, mainly Coxsackieviruses of different serotypes as well as Enterovirus 71.

Coxsackievirus B4: a Undervalued Pathogen that Associated with Hand, Foot and Mouth Disease Outbreak

Objectives: This study was conducted to discover the causes of Coxsackievirus B4 (CVB4) -induced hand, foot, and mouth disease (HFMD) outbreaks and its evolutionary characteristics.Methods: In this study, we sequenced isolates obtained during the outbreak for comparative analyses with previously sequenced strains. Phylogenetic analysis and evolutionary dynamics were performed to illustrate the genetic characteristics of CVB4 in China and worldwide.Results: The nucleotide sequence of CVB4 isolated during the outbreak in 2011 was more similar to that of CVB4 isolated in Shandong Province, China in 2010 (95.7–99.4%) than to other CVB4 isolated in China (90.9–98.8%). A phylogenetic analysis showed that CVB4 originated from a common ancestor in Shandong. CVB4 strains isolated worldwide could be classified into genotypes A–E according to the VP1 region. All CVB4 strains in China belonged to genotype E. The global population diversity of CVB4 fluctuated substantially over time, and CVB4 isolated from China accounted for a significant increase in diversity of CVB4. The average nucleotide substitution rate in VP1 of Chinese CVB4 (5.20 × 10-3 substitutions/site/year) was slightly higher than that of global CVB4 (4.82 × 10-3 substitutions/site/year). Conclusions: These findings explain both the 2011 outbreak and a global increase in CVB4 diversity. In addition to improving our understanding of a major outbreak, these findings provide a basis for the development of surveillance strategies.

Modulation of IGF2 Expression in the Murine Thymus and Thymic Epithelial Cells Following Coxsackievirus-B4 Infection

Coxsackievirus B4 (CV-B4) can infect human and murine thymic epithelial cells (TECs). In a murine TEC cell line, CV-B4 can downregulate the transcription of the insulin-like growth factor 2 (Igf2) gene coding for the self-peptide of the insulin family. In this study, we show that CV-B4 infections of a murine TEC cell line decreased Igf2 P3 promoter activity by targeting a region near the transcription start site; however, the stability of Igf2 transcripts remained unchanged, indicating a regulation of Igf2 transcription. Furthermore, CV-B4 infections decreased STAT3 phosphorylation in vitro. We also showed that mice infected with CV-B4 had an altered expression of Igf2 isoforms as detected in TECs, followed by a decrease in the pro-IGF2 precursor in the thymus. Our study sheds new light on the intrathymic regulation of Igf2 transcription during CV-B4 infections and supports the hypothesis that a viral infection can disrupt central self-tolerance to insulin by decreasing Igf2 transcription in the thymic epithelium.

Environmental Surveillance through Next-Generation Sequencing to Unveil the Diversity of Human Enteroviruses beyond the Reported Clinical Cases

The knowledge about circulation of Human Enteroviruses (EVs) obtained through medical diagnosis in Argentina is scarce. Wastewater samples monthly collected in Córdoba, Argentina during 2011–2012, and then in 2017–2018 were retrospectively studied to assess the diversity of EVs in the community. Partial VP1 gene was amplified by PCR from wastewater concentrates, and amplicons were subject of next-generation sequencing and genetic analyses. There were 41 EVs detected, from which ~50% had not been previously reported in Argentina. Most of the characterized EVs (60%) were detected at both sampling periods, with similar values of intratype nucleotide diversity. Exceptions were enterovirus A71, coxsackievirus B4, echovirus 14, and echovirus 30, which diversified in 2017–2018. There was a predominance of types from EV-C in 2017–2018, evidencing a common circulation of these types throughout the year in the community. Interestingly, high genetic similarity was evidenced among environmental strains of echovirus 30 circulating in 2011–2012 and co-temporal isolates obtained from patients suffering aseptic meningitis in different locations of Argentina. This study provides an updated insight about EVs circulating in an important region of South America, and suggests a valuable role of wastewater-based epidemiology in predicting outbreaks before the onset of cases in the community.