The rapidly increasing incidence of type 1 diabetes implies that environmental factors are involved in the pathogenesis. Enteroviruses are among the suspected environmental triggers of the disease, and the interest in exploring the possibilities to develop vaccines against these viruses has increased. Our objective was to identify enterovirus serotypes that could be involved in the initiation of the disease process by screening neutralizing antibodies against 41 different enterovirus types in a unique longitudinal sample series from a large prospective birth-cohort study. The study participants comprised 183 case children testing persistently positive for at least two diabetes-predictive autoantibodies and 366 autoantibody-negative matched control children. Coxsackievirus B1 was associated with an increased risk of β-cell autoimmunity. This risk was strongest when infection occurred a few months before autoantibodies appeared and was attenuated by the presence of maternal antibodies against the virus. Two other coxsackieviruses, B3 and B6, were associated with a reduced risk, with an interaction pattern, suggesting immunological cross-protection against coxsackievirus B1. These results support previous observations suggesting that the group B coxsackieviruses are associated with the risk of type 1 diabetes. The clustering of the risk and protective viruses to this narrow phylogenetic lineage supports the biological plausibility of this phenomenon.

CVB1 infections may contribute to the initiation of islet autoimmunity being particularly important in the insulin-driven autoimmune process.

Aims/hypothesis This case-control study was nested in a prospective birth cohort to evaluate whether the presence of enteroviruses in stools was associated with the appearance of islet autoimmunity in the Type 1 Diabetes Prediction and Prevention study in Finland. Methods Altogether, 1673 longitudinal stool samples from 129 case children who turned positive for multiple islet autoantibodies and 3108 stool samples from 282 matched control children were screened for the presence of enterovirus RNA using RT-PCR. Viral genotype was detected by sequencing.Results Case children had more enterovirus infections than control children (0.8 vs 0.6 infections per child). Timedependent analysis indicated that this excess of infections occurred more than 1 year before the first detection of islet autoantibodies (6.3 vs 2.1 infections per 10 follow-up years). No such difference was seen in infections occurring less than 1 year before islet autoantibody seroconversion or after seroconversion. The most frequent enterovirus types included coxsackievirus A4 (28% of genotyped viruses), coxsackievirus A2 (14%) and coxsackievirus A16 (11%). Conclusions/interpretationThe results suggest that enterovirus infections diagnosed by detecting viral RNA in stools are Electronic supplementary material The online version of this article

The infectious cycles of viruses are known to cause dramatic changes to host cell function. The development of microarray technology has provided means to monitor host cell responses to viral infection at the level of global changes in mRNA levels. We have applied this methodology to investigate gene expression changes caused by a small, icosahedral, single-stranded-RNA phage, PRR1 (a member of the Leviviridae family), on its host, Pseudomonas aeruginosa, at different times during its growth cycle. Viral infection in this system resulted in changes in expression levels of <4% of P. aeruginosa genes. Interestingly, the number of genes affected by viral infection was significantly lower than the number of genes affected by changes in growth conditions during the experiment. Compared with a similar study that focused on the complex, double-stranded-DNA bacterial virus PRD1, it was evident that there were no universal responses to viral infection. However, in both cases, translation was affected in infected cells.Over the past few years, microarray technology has been employed to probe the global effects of viral infection on host gene expression (26,27). The earliest microarray-based studies of host gene expression provided a very general, genome-wide picture of changes induced by viral infection. These studies, however, provided little information about the specific changes in individual genes across the entire host genome. Furthermore, investigations using this technology have largely focused on viral infections in animals and, to a lesser extent, in plants (21,30,35) or fungi (2, 3). Microarrays have been employed to detect phage-specific transcripts in infected cells (11,19), changes in the host genome (14,20), and changes in the transcriptional profiles of bacteria parasitized by lysogenic phages (7). However, to our knowledge, only two studies of virusinduced changes in host gene expression span the entire host genome. One of these studies involved a plant virus (21), and the other focused on an icosahedral, membrane-containing, double-stranded-DNA (dsDNA) phage, PRD1 (27).PRR1 is an icosahedral, single-stranded-RNA (ssRNA) phage (24) that is related to well-studied members (MS2, Qbeta, etc.) of the Leviviridae family (13). PRR1 is unique among members of the Leviviridae family in that it infects a wide range of gram-negative bacteria (8, 24), but only if they harbor an IncP-type conjugative plasmid. The PRR1 genome contains 3,573 nucleotides with only four protein-encoding genes, namely, those for the polymerase, the maturation and coat proteins, and the lytic factor (28). The PRR1 replication cycle and its effects on host cell physiology are described elsewhere (G. Daujotaitë, R. Daugelavièius, and D. H. Bamford, submitted for publication). The optimal bacterial host for PRR1 is Pseudomonas aeruginosa (24), a gram-negative, opportunistic human pathogen (15,16,18). At 6.3 million base pairs (containing 5,570 open reading frames [ORFs]), the P. aeruginosa genome is one of the largest bacterial genomes that ha...

Myeloid neoplasms with erythroid or megakaryocytic differentiation include pure erythroid leukemia (PEL), myelodysplastic syndrome (MDS) with erythroid features, and acute megakaryoblastic leukemia (FAB M7) and are characterized by poor prognosis and limited treatment options. Here, we investigate the drug sensitivity landscape of these rare malignancies. We show that acute myeloid leukemia (AML) cells with erythroid or megakaryocytic differentiation depend on the anti-apoptotic protein BCL-XL, rather than BCL-2, using combined ex vivo drug sensitivity testing, genetic perturbation, and transcriptomic profiling. High-throughput screening of &gt; 500 compounds identified the BCL-XL-selective inhibitor A-1331852 and navitoclax as highly effective against erythroid/megakaryoblastic leukemia cell lines. In contrast, these AML subtypes were resistant to the BCL-2 inhibitor venetoclax used clinically in the treatment of AML. Consistently, genome-scale CRISPR-Cas9 and RNAi screening data demonstrated striking essentiality of BCL2L1 encoding BCL-XL, but not BCL2 or MCL1, for the survival of erythroid/megakaryoblastic leukemia cell lines. Single-cell and bulk transcriptomics of patient samples with erythroid and megakaryoblastic leukemias identified high BCL2L1 expression compared to other subtypes of AML and other hematological malignancies, where BCL2 and MCL1 were more prominent. BCL-XL inhibition effectively killed blasts in AML patient samples with erythroid or megakaryocytic differentiation ex vivo and reduced tumor burden in a mouse erythroleukemia xenograft model. Combining BCL-XL inhibitor with the JAK inhibitor ruxolitinib showed synergistic and durable responses in cell lines. Our results suggest targeting BCL-XL as a potential therapy option in erythroid/megakaryoblastic leukemias and highlight an AML subgroup with potentially reduced sensitivity to venetoclax-based treatments.

No abstract

Single-stranded RNA (ssRNA) bacteriophages of the family Leviviridae infect gram-negative bacteria. They are restricted to a single host genus. Phage PRR1 is an exception, having a broad host range due to the promiscuity of the receptor encoded by the IncP plasmid. Here we report the complete genome sequence of PRR1. Three proteins homologous with those of other ssRNA phages, i.e., maturation, coat, and replicase proteins, were identified. A fourth protein has a lysis function. Comparison of PRR1 with other members of the Leviviridae family places PRR1 in the genus Levivirus with some characteristics more similar to those of members of the genus Allolevivirus.

The BCL2 inhibitor venetoclax has revolutionized the treatment of acute myeloid leukemia (AML) patients not benefitting from intensive chemotherapy. Nevertheless, treatment failure remains a challenge, and predictive markers are needed, particularly for relapsed or refractory (R/R) AML. Ex vivo drug sensitivity testing may correlate with outcomes, but its prospective predictive value remains unexplored. Here we report the results of the first stage of the prospective Phase 2 VenEx trial evaluating the utility and predictiveness of venetoclax sensitivity testing using different cell culture conditions and cell viability assays in patients receiving venetoclax-azacitidine (NCT04267081). Participants with de novo AML ineligible for intensive chemotherapy, R/R AML, or secondary AML were included. The primary endpoint was the treatment response in ex vivo sensitive participants and the key secondary endpoints were the correlation of sensitivity with responses and survival. Venetoclax sensitivity testing was successful in 38/39 participants. Experimental conditions significantly influenced predictive accuracy. Blast-specific venetoclax sensitivity measured in conditioned medium most accurately correlated with treatment outcomes; 88% of sensitive participants achieved treatment response. Median survival was significantly longer for ex vivo sensitive participants (14. 6 months for s ensitive, 3. 5 for insensitive, p < 0 . 001). T his analysis illustrates the feasibility of integrating drug-response profiling into clinical practice and demonstrates excellent predictivity.