Metabolism is a critical immune regulator under physiologic and pathologic conditions. Culminating evidence has disentangled the contribution of distinct metabolic pathways, namely glucolysis, pentose phosphate, fatty acid oxidation, glutaminolysis, Krebs cycle and oxidative phosphorylation, in modulating innate and adaptive immune cells based on their activation/differentiation state. Metabolic aberrations and changes in the intracellular levels of specific metabolites are linked to the inflammatory phenotype of immune cells implicated in autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis and diabetes. Notably, targeting metabolism such as the mTOR by rapamycin, hexokinase by 2-deoxy-D-glucose, AMP-activated protein kinase by metformin, may be used to ameliorate autoimmune inflammation. Accordingly, research in immunometabolism is expected to offer novel opportunities for monitoring and treating immune-mediated diseases.

Objectives: Asymptomatic bacteriuria (ASB) is a common finding in patients with diabetes. Moreover, patients with diabetes and ASB have a greater risk for symptomatic urinary tract infections and associated severe complications. The aim of this study was to estimate the prevalence of ASB, as well as to identify independent risk factors and related pathogens associated with ASB in female and male patients with type 2 diabetes mellitus (T2D). Methods: This prospective case-control study was performed at the University hospital, and the Venezeleion General Hospital, Heraklion, Greece between 2012 and 2019. All patients with T2D attending the diabetes and hypertension outpatient clinics at both hospitals were enrolled, and data regarding their medical history and clinical and laboratory profiles were recorded. Asymptomatic patients with positive urine cultures were assigned as cases while those with negative urine cultures were designated as controls. Results: A total of 437 adult patients of which 61% were female and 39% were male patients with a mean age of 70.5 ± 9.6 years, were enrolled. The prevalence of ASB was 20.1%, in total. ASB was noted in 27% of female participants and 9.4% of male participants. Higher glycated hemoglobin (OR = 3.921, 95%CI: 1.521–10.109, p < 0.001) and urinary tract infection within the previous year (OR = 13.254, 95%CI: 2.245–78.241, p < 0.001) were independently positively associated with ASB, while higher levels of vitamin B12 were independently negatively associated with ASB (OR = 0.994 per ng/mL, 95%CI: 0.989–0.999, p < 0.001). Conclusions: Development of ASB was associated with specific factors, some of which may be modifiable. Interestingly, high B12 was found to be negatively associated with ASB.

It is becoming increasingly appreciated that the non-coding genome may have a great impact on the regulation of chromatin structure and gene expression. The innate immune response can be mediated upon lipopolysaccharide stimulation of macrophages which leads to immediate transcriptional activation of early responsive genes including tumor necrosis factor alpha (Tnfα). The functional role of non-coding RNAs, such as lncRNAs and microRNAs, on the transcriptional activation of proinflammatory genes and the subsequent regulation of the innate immune response is still lacking mechanistic insights. In this study we wanted to unravel the functional role of the lncRNA SeT, which is encoded from the murine Tnfα gene locus, and miR-155 on the transcriptional regulation of the Tnfα gene. We utilized genetically modified mice harboring either a deletion of the SeT promoter elements or the mature miR-155 and studied the response of macrophages to lipopolysaccharide (LPS) stimulation. We found that decreased expression of the lncRNA SeT in murine primary macrophages resulted in increased mortality of mice challenged with LPS, which was corroborated by increased Tnfα steady state mRNA levels and a higher frequency of biallelically expressing macrophages. On the contrary, miR-155 deletion resulted in reduced Tnfα mRNA levels supported by a lower frequency of biallelically expressing macrophages upon stimulation with LPS. In both cases, in the absence of either lncRNA SeT or miR-155 we observed a deregulation of the Tnfα allele homologous pairing, previously shown to regulate the switch from mono- to bi-allelic gene expression. Although lncRNA SeT was not found to be a direct target of miR-155 its stability was increased upon miR-155 deletion. This study suggests a role of the non-coding genome in mediating Tnfα mRNA dosage control based on the regulation of homologous pairing of gene alleles and their subsequent biallelic expression.

microRNAs are of vital importance for the regulation of the adaptive and innate immune responses, modulating gene expression at the post transcriptional level. Although there is cumulative information regarding the steady state mature microRNA levels and their respective targets, little is known about the effect of the three-dimensional chromatin architecture on the transcriptional regulation of microRNA gene loci. Here, we sought to investigate the effect of subnuclear localization on the transcriptional activation of eight murine microRNA loci in the immune system. Our results show that microRNA genes display a preferential monoallelic gene expression profile accompanied with perinuclear localization irrespectively of their transcription status or differentiation state. The expression profile and perinuclear localization are developmentally conserved while microRNA gene loci localization outside constitutive lamin associated domains is cross-species conserved. Our findings provide support for an active nuclear periphery and its role in chromatin organization of the non-coding genome.

binds FcgRs, as well as some nuclear proteins, including snRNPs. Pentameric (native) CRP has previously been suggested to inhibit production of IFNs in peripheral mononuclear cells (PBMCs) in response to ICs formed by autoantibodies against snRNP, an effect which was further investigated herein. Methods PBMCs or magnetically (MACS) purified pDCs were retrieved from whole blood of healthy volunteers. Type I IFN gene transcription and production was stimulated by addition of snRNP containing ICs ± pentameric CRP (pCRP) or monomeric CRP (mCRP) in different sequential order. IC formation was achieved through simultaneous addition of snRNP and bulk IgG, retrieved from an SLE patient with high levels of snRNP autoantibodies, directly to the cells. Type I IFNs and inflammatory cytokines were investigated using quantitative PCR, ELISA and cytometric bead array, and cells responsible for production of the IFNs were characterized using flow cytometry. For statistics a two-tailed t-test was performed. Results pCRP had an inhibitory effect on the IFN gene expression in PBMCs after incubation with ICs, p=0.044 for IFNa4 and p=0.047 for IFNb at the 4h time-point compared to IC only. pCRP also showed a dose-dependent inhibitory effect on the type I IFN production in the cells. The monomeric form of CRP showed modest or no effect on IFN levels, p=0.82 for IFNa4 and p=0.58 for IFNb at the 4h time-point compared to IC only. A pre-incubation of the cells with pCRP increased the inhibitory effects compared to simultaneous addition of pCRP and ICs, suggesting that initial binding to the cells is a critical step for inhibition. Flow cytometry suggested that pDCs are the main producer of the type I IFNs. In addition, pCRP seems to have a more general inhibitory effect on type I IFNs, as seen in the reduction of IFN production in response to the TLR-9 ligand CpG. Conclusions pCRP has a distinct inhibitory effect on type I IFNs, which is largely not seen for the dissociated form of CRP (mCRP). The more general inhibitory effects shown by pCRP highlights its immune regulatory function in pathologies characterized by high production of type I IFNs. The identity of the initial receptors responsible for pCRP mediated effects, as well as of the involved signaling pathways, will be further investigated.

A remarkable, yet poorly explained feature of Systemic Lupus Erythematosus (SLE) is the propensity to flare following a preceding period of disease inactivity. The clinical burden of lupus flares is substantial since they often tend to involve multiple or major organs, and carry a near two-fold increased risk for accrual of irreversible organ damage. The cellular and molecular mechanisms underlying the progression of SLE from inactive to active state remain ill-defined. Application of novel sequencing technologies together with cellular immunology assays, have illustrated the important role of multiple types of both innate and adaptive cells and associated pathways. We have previously described significant differences in the blood transcriptome of SLE patients at active versus inactive disease, and we have also defined genome regions (domains) with co-ordinated expression of genes implicated in the disease. In the present study, we aim to decipher the cellular and molecular basis of SLE exacerbations by utilising novel single-cell sequencing approaches, which allow us to characterise the transcriptional and epigenetic landscapes of thousands of cells in the peripheral blood of patients. The significance of the study lies in the detailed characterisation of the molecular and regulatory program of immune cell subpopulations that underlie progression from inactive to active SLE. Accordingly, our results may be exploited to identify biomarkers for disease monitoring and novel therapeutic targets.

Background and Objectives: Asymptomatic bacteriuria (ASB) appears to have a higher prevalence in diabetics and has been associated with various genetic polymorphisms of the innate immune system. Single nucleotide polymorphisms (SNPs) of the C1q gene that encodes for the trigger molecule of the classical complement pathway increase the risk of bacterial infections as well as other diseases. In the present study, we sought to investigate the association of C1q rs292001 (G > A) SNP with ASB in patients with type 2 diabetes (T2D). Materials and Methods: In this case-control study, performed at the University and the Venizeleion General Hospital of Heraklion, Crete, Greece, 75 adult male and female Cretan patients with T2D and ASB and 75 adult male and female Cretan patients with T2D but without ASB were enrolled and genotyped for rs292001 SNP of C1q gene. Genetic analysis was based on the polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RLFPs) methods. Results: Τhe frequency of homozygotes for the G/G genotype of C1q rs292001 was significantly higher in patients with T2D and ASB than in the control group (p-value = 0.0480, OR = 2.952, 95% CI: 1.052–7.542). Conclusions: Τhe present study provides the first evidence of an association between the C1q rs292001 SNP and an increased susceptibility for ASB in an adult Cretan population with T2D, thus suggesting that this SNP can be encountered as a risk factor for the presence of ASB in patients with T2D.