Identifying transplant recipients in whom immunological tolerance is established or is developing would allow an individually tailored approach to their posttransplantation management. In this study, we aimed to develop reliable and reproducible in vitro assays capable of detecting tolerance in renal transplant recipients. Several biomarkers and bioassays were screened on a training set that included 11 operationally tolerant renal transplant recipients, recipient groups following different immunosuppressive regimes, recipients undergoing chronic rejection, and healthy controls. Highly predictive assays were repeated on an independent test set that included 24 tolerant renal transplant recipients. Tolerant patients displayed an expansion of peripheral blood B and NK lymphocytes, fewer activated CD4 + T cells, a lack of donor-specific antibodies, donor-specific hyporesponsiveness of CD4 + T cells, and a high ratio of forkhead box P3 to α-1,2-mannosidase gene expression. Microarray analysis further revealed in tolerant recipients a bias toward differential expression of B cell-related genes and their associated molecular pathways. By combining these indices of tolerance as a cross-platform biomarker signature, we were able to identify tolerant recipients in both the training set and the test set. This study provides an immunological profile of the tolerant state that, with further validation, should inform and shape drug-weaning protocols in renal transplant recipients.

T-bet and GATA3 regulate the CD4+ T cell Th1/Th2 cell fate decision but little is known about the interplay between these factors outside of the murine Ifng and Il4/Il5/Il13 loci. Here we show that T-bet and GATA3 bind to multiple distal sites at immune regulatory genes in human effector T cells. These sites display markers of functional elements, act as enhancers in reporter assays and are associated with a requirement for T-bet and GATA3. Furthermore, we demonstrate that both factors bind distal sites at Tbx21 and that T-bet directly activates its own expression. We also show that in Th1 cells, GATA3 is distributed away from Th2 genes, instead occupying T-bet binding sites at Th1 genes, and that T-bet is sufficient to induce GATA3 binding at these sites. We propose these aspects of T-bet and GATA3 function are important for Th1/Th2 differentiation and for understanding transcription factor interactions in other T cell lineage decisions.

Chronic kidney disease (CKD), impairment of kidney function, is a serious public health problem, and the assessment of genetic factors influencing kidney function has substantial clinical relevance. Here, we report a meta-analysis of genome-wide association studies for kidney function–related traits, including 71,149 east Asian individuals from 18 studies in 11 population-, hospital- or family-based cohorts, conducted as part of the Asian Genetic Epidemiology Network (AGEN). Our meta-analysis identified 17 loci newly associated with kidney function–related traits, including the concentrations of blood urea nitrogen, uric acid and serum creatinine and estimated glomerular filtration rate based on serum creatinine levels (eGFRcrea) (P < 5.0 × 10−8). We further examined these loci with in silico replication in individuals of European ancestry from the KidneyGen, CKDGen and GUGC consortia, including a combined total of ~110,347 individuals. We identify pleiotropic associations among these loci with kidney function–related traits and risk of CKD. These findings provide new insights into the genetics of kidney function.

Key Points• C3aR activation increases ATP efflux, NLRP3 inflammasome activation, and IL-1b secretion in human monocytes.• C3aR-activated monocytes drive Th17 responses in vitro and likely in vivo.Interleukin-1b (IL-1b) is a proinflammatory cytokine and a therapeutic target in several chronic autoimmune states. Monocytes and macrophages are the major sources of IL-1b. IL1b production by these cells requires Toll-like receptor (TLR) and adenosine triphosphate (ATP)-mediated P2X purinoceptor 7 (P2X7) signals, which together activate the inflammasome. However, how TLR signals and ATP availability are regulated during monocyte activation is unclear and the involvement of another danger signal system has been proposed. Here, we demonstrate that both lipopolysaccharide (LPS) and the anaphylatoxin C3a are needed for IL-1b production in human macrophages and dendritic cells, while in monocytes, C3a enhanced the secretion of LPS-induced IL-1b. C3a and LPS-stimulated monocytes increased T helper 17 (Th17) cell induction in vitro, and human rejecting, but not nonrejecting, kidney transplant biopsies were characterized by local generation of C3a and monocyte and Th17 cell infiltration. Mechanistically, C3a drives IL-1b production in monocytes by controlling the release of intracellular ATP into the extracellular space via regulation of as-yet unidentified ATPreleasing channels in an extracellular signal-regulated kinase 1/2-dependent fashion. These data define a novel function for complement in inflammasome activation in monocytes and suggest that C3aR-mediated signaling is a vital component of the IL1b-Th17 axis. (Blood. 2013;122(20):3473-3481) IntroductionInterleukin-1b (IL-1b) is a key proinflammatory cytokine involved in host responses to pathogens and tissue injury. IL-1b has gathered substantial interest in recent years because several autoimmune disorders respond specifically to IL-1 receptor blockade using either soluble IL-1 receptor antagonists or blocking monoclonal antibodies (mAbs).1 In addition to inducing neutrophil activation and histamine release by mast cells and maintaining epithelial cell integrity, 2 IL-1b also plays a central role in modulating adaptive effector T-cell responses by preferentially inducing T helper 1 (Th1) and Th17 differentiation.3 In humans, CD4 1 T cells require IL-1b and IL-6 to differentiate into Th17 cells, 4 which contribute to the pathophysiology of inflammatory and autoimmune diseases 5 as well as ischemia reperfusion injury (IRI) and transplant rejection. Monocytes, macrophages, and dendritic cells (DCs) are major IL-1b sources and release this cytokine in response to stimuli such as pathogen-associated or danger-associated molecular patterns (PAMPs or DAMPs) mediated by signaling via several Toll-like receptor (TLR) pathways. 7 Although consensus exists that IL-1b generation requires processing of the 31 K D inactive pro-IL-1b to the 17 K D active form by caspase-1 activation via an inflammasome complex (eg, NLRP3), 8,9 signals leading to NLRP3 and caspase-1 activation are...

Chronic kidney disease (CKD), the result of permanent loss of kidney function, is a major global problem. We identify common genetic variants at chr2p12-p13, chr6q26, chr17q23 and chr19q13 associated with serum creatinine, a marker of kidney function (P=10−10 to 10−15). SNPs rs10206899 (near NAT8, chr2p12-p13) and rs4805834 (near SLC7A9, chr19q13) were also associated with CKD. Our findings provide new insight into metabolic, solute and drug-transport pathways underlying susceptibility to CKD.

Asymmetric cell division is an important mechanism for generating cellular diversity, however, techniques for measuring the distribution of fate-regulating molecules during mitosis have been hampered by a lack of objectivity, quantitation, and statistical robustness. Here we describe a novel imaging flow cytometric approach that is able to report a cells proliferative history and cell cycle position using dye dilution, pH3, and PI staining to then measure the spatial distribution of fluorescent signals during mitosis using CCD-derived imagery. Using Jurkat cells, resolution of the fluorescently labeled populations was comparable to traditional PMT based cytometers thus eliminating the need to sort cells with specific division histories for microscopy. Subdividing mitotic stages by morphology allowed us to determine the time spent in each cell cycle phase using mathematical modeling approaches. Furthermore high sample throughput allowed us to collect statistically relevant numbers of cells without the need to use blocking agents that artificially enrich for mitotic events. The fluorescent imagery was used to measure PKCf protein and EEA-11 endosome distribution during different mitotic phases in Jurkat cells. While telophase cells represented the favorable population for measuring asymmetry, asynchronously dividing cells spent approximately 43 seconds in this stage, explaining why they were present at such low frequencies. This necessitated the acquisition of large cell numbers. Interestingly we found that PKCf was inherited asymmetrically in 2.5% of all telophasic events whereas endosome inheritance was significantly more symmetrical. Furthermore, molecular polarity at early mitotic phases was a poor indicator of asymmetry during telophase highlighting that, though rare, telophasic events represented the best candidates for asymmetry studies. In summary, this technique combines the spatial information afforded by fluorescence microscopy with the statistical wealth and objectivity of traditional flow cytometry, overcoming the key limitations of existing approaches for studying asymmetry during mitosis. ' 2011International Society for Advancement of Cytometry Key termsimaging flow cytometry; cell cycle analysis; asymmetric cell division; flow cytometry; image analysis DETERMINING how fate decisions are made at the molecular level is key to understanding how single cell progenitors can generate different specialized cell types. This diversification can occur in two ways. When a cell divides by mitosis, equal distribution of fate determining molecules across the plane of cytokinesis will produce two identical daughter cells that can differentiate in response to extrinsic stimuli. Alternatively, if fate determinants are apportioned asymmetrically prior to cytokinesis, two qualitatively and quantitatively distinct progeny will be generated by division (1,2). Asymmetric division is a key process for driving cellular diversity in developmental biology (3-7), stem cell biology (4,(8)(9)(10) and also recently in...

SummaryLow-grade inflammation in fat is associated with insulin resistance, although the mechanisms are unclear. We report that mice deficient in the immune cell transcription factor T-bet have lower energy expenditure and increased visceral fat compared with wild-type mice, yet paradoxically are more insulin sensitive. This striking phenotype, present in young T-bet−/− mice, persisted with high-fat diet and increasing host age and was associated with altered immune cell numbers and cytokine secretion specifically in visceral adipose tissue. However, the favorable metabolic phenotype observed in T-bet-deficient hosts was lost in T-bet−/− mice also lacking adaptive immunity (T-bet−/−xRag2−/−), demonstrating that T-bet expression in the adaptive rather than the innate immune system impacts host glucose homeostasis. Indeed, adoptive transfer of T-bet-deficient, but not wild-type, CD4+ T cells to Rag2−/− mice improved insulin sensitivity. Our results reveal a role for T-bet in metabolic physiology and obesity-associated insulin resistance.

The mechanisms controlling CD4+ T cell switching from an effector to an anti-inflammatory (IL-10+) phenotype play an important role in the persistence of chronic inflammatory diseases. Here, we identify the cholesterol biosynthesis pathway as a key regulator of this process. Pathway analysis of cultured cytokine-producing human T cells reveals a significant association between IL-10 and cholesterol metabolism gene expression. Inhibition of the cholesterol biosynthesis pathway with atorvastatin or 25-hydroxycholesterol during switching from IFNγ+ to IL-10+ shows a specific block in immune resolution, defined as a significant decrease in IL-10 expression. Mechanistically, the master transcriptional regulator of IL10 in T cells, c-Maf, is significantly decreased by physiological levels of 25-hydroxycholesterol. Strikingly, progression to rheumatoid arthritis is associated with altered expression of cholesterol biosynthesis genes in synovial biopsies of predisposed individuals. Our data reveal a link between sterol metabolism and the regulation of the anti-inflammatory response in human CD4+ T cells.