The rockefeller university

Therapeutic interventions in colorectal cancer are dependent on immune responses to dying epithelial cells that are modulated by specific members of the gut microbiota.

Dynamic trafficking of G protein-coupled receptors (GPCRs) out of cilia is mediated by the BBSome. In concert with its membrane recruitment factor, the small GTPase ARL6/BBS3, the BBSome ferries GPCRs across the transition zone, a diffusion barrier at the base of cilia. Here, we present the near-atomic structures of the BBSome by itself and in complex with ARL6(GTP), and we describe the changes in BBSome conformation induced by ARL6(GTP) binding. Modeling the interactions of the BBSome with membranes and the GPCR Smoothened (SMO) reveals that SMO, and likely also other GPCR cargoes, must release their amphipathic helix 8 from the membrane to be recognized by the BBSome.

Mendelian susceptibility to mycobacterial disease (MSMD) is characterized by a selective predisposition to clinical disease caused by the Bacille Calmette-Guerin (BCG) vaccine and environmental mycobacteria. The known genetic etiologies of MSMD are inborn errors of IFN-gamma immunity due to mutations of 15 genes controlling the production of or response to IFN-gamma. Since the first MSMD-causing mutations were reported in 1996, biallelic mutations in the genes encoding IFN-gamma receptor 1 (IFN-gamma R1) and IFN-gamma R2 have been reported in many patients of diverse ancestries. Surprisingly, mutations of the gene encoding the IFN-gamma cytokine itself have not been reported, raising the remote possibility that there might be other agonists of the IFN-gamma receptor. We describe 2 Lebanese cousins with MSMD, living in Kuwait, who are both homozygous for a small deletion within the IFNG gene (c.354_357del), causing a frameshift that generates a premature stop codon (p.T1191fs4*). The mutant allele is loss of expression and loss of function. We also show that the patients' herpesvirus Saimiri-immortalized T lymphocytes did not produce IFN-gamma, a phenotype that can be rescued by retrotransduction with WT IFNG cDNA. The blood T and NK lymphocytes from these patients also failed to produce and secrete detectable amounts of IFN-gamma. Finally, we show that human IFNG has evolved under stronger negative selection than IFNGIV or IFNGR2, suggesting that it is less tolerant to heterozygous deleterious mutations than IFNGIV or IFNGR2. This may account for the rarity of patients with autosomal-recessive, complete IFN-gamma deficiency relative to patients with complete IFN-gamma R1 and IFN-gamma R2 deficiencies.

Background There is a need for valid and reliable biomarkers in hidradenitis suppurativa (HS) for diagnosis and disease activity monitoring. Imaging-based biomarkers have the potential to fulfil this unmet need but no evaluation of analytical or clinical validity has yet been undertaken. Objectives To evaluate the analytical and clinical validity of sonographic epidermal thickness, Doppler ultrasound and dermal tunnel diameter in patients with HS. Methods Twenty-two participants with HS were recruited and underwent a total of 65 matched ultrasound and skin biopsies of lesional, perilesional and unaffected tissue. Ultrasound measurements were performed in triplicate with mean values used. Skin biopsies underwent immunohistochemistry as per previously published methods. Analytical validity was assessed in individual ultrasound-biopsy pairs (n= 65) by comparisons of sonographic variables with histological correlates. Clinical validity was assessed in individual patients (n= 22) by comparing measures of overall disease activity with sonographic outcomes. Results Epidermal thickness, dermal tunnel diameter and power Doppler intensity were assessed. Sonographic epidermal thickness and dermal tunnel diameter have high analytical validity with corresponding histological measurements. Power Doppler intensity demonstrated high correlation with dermal CD3(+)and CD11c(+)cell counts but not neutrophil elastase-positive cells. Power Doppler ultrasound has significant correlation with pain scores, abscess and nodule count, International HS Severity Scoring System score and number of draining tunnels. Conclusions Sonographic epidermal thickness and dermal tunnel diameter have acceptable levels of analytical validity in the assessment of HS lesions. Power Doppler intensity demonstrates acceptable clinical and analytical validity, suggesting it is a valid imaging-based biomarker in HS.

Many bacteria can cause pyogenic lesions in humans. Most of these bacteria are harmless in most individuals, but they, nevertheless, cause significant morbidity and mortality worldwide. The inherited and acquired immunodeficiencies underlying these pyogenic infections differ between bacteria. This short review focuses on two emblematic pyogenic bacteria: pneumococcus (Streptococcus pneumoniae) and Staphylococcus, both of which are Gram-positive encapsulated bacteria. We will discuss the contribution of human genetic studies to the identification of germline mutations of the TLR and IL-1R pathways.

Interferon-gamma receptor 1 (IFN gamma R1) deficiency is one of the inborn errors of IFN-gamma immunity underlying Mendelian Susceptibility to Mycobacterial Disease (MSMD). This molecular circuit plays a crucial role in regulating the interaction between dendritic cells (DCs) and T lymphocytes, thus affecting DCs activation, maturation, and priming of T cells involved in the immune response against intracellular pathogens. We studied a girl who developed at the age of 2.5 years aMycobacterium aviuminfection characterized by disseminated necrotizing granulomatous lymphadenitis, and we compared her findings with other patients with the same genetic condition. The patient carried a heterozygous 818del4 mutation in theIFNGR1gene responsible of autosomal dominant (AD) partial IFN gamma R1 deficiency. During the acute infection blood cells immunophenotyping showed a marked reduction in DCs counts, including both myeloid (mDCs) and plasmacytoid (pDCs) subsets, that reversed after successful prolonged antimicrobial therapy. Histology of her abdomen lymph node revealed a profound depletion of tissue pDCs, as compared to other age-matched granulomatous lymphadenitis of mycobacterial origin. Circulating DCs depletion was also observed in another patient with AD partial IFN gamma R1 deficiency during mycobacterial infection. To conclude, AD partial IFN gamma R1 deficiency can be associated with a transient decrease in both circulating and tissular DCs during acute mycobacterial infection, suggesting that DCs counts monitoring might constitute a useful marker of treatment response.

Comparative transcriptomics between differentiating human pluripotent stem cells (hPSCs) and developing mouse neurons offers a powerful approach to compare genetic and epigenetic pathways in human and mouse neurons. To analyze human Purkinje cell (PC) differentiation, we optimized a protocol to generate human pluripotent stem cell-derived Purkinje cells (hPSC-PCs) that formed synapses when cultured with mouse cerebellar glia and granule cells and fired large calcium currents, measured with the genetically encoded calcium indicator jRGECO1a. To directly compare global gene expression of hPSC-PCs with developing mouse PCs, we used translating ribosomal affinity purification (TRAP). As a first step, we used Tg(Pcp2-L10a-Egfp) TRAP mice to profile actively transcribed genes in developing postnatal mouse PCs and used metagene projection to identify the most salient patterns of PC gene expression over time. We then created a transgenic Pcp2-L10a-Egfp TRAP hPSC line to profile gene expression in differentiating hPSC-PCs, finding that the key gene expression pathways of differentiated hPSC-PCs most closely matched those of late juvenile mouse PCs (P21). Comparative bioinformatics identified classical PC gene signatures as well as novelmitochondrial and autophagy gene pathways during the differentiation of both mouse and human PCs. In addition, we identified genes expressed in hPSC-PCs but not mouse PCs and confirmed protein expression of a novel human PC gene, CD40LG, expressed in both hPSC-PCs and native human cerebellar tissue. This study therefore provides a direct comparison of hPSC-PC and mouse PC gene expression and a robust method for generating differentiated hPSC-PCs with human-specific gene expression for modeling developmental and degenerative cerebellar disorders.

Autosomal dominant hyper-IgE syndrome (AD-HIES) is typically caused by dominant-negative (DN) STAT3 mutations. Patients suffer from cold staphylococcal lesions and mucocutaneous candidiasis, severe allergy, and skeletal abnormalities. We report 12 patients from 8 unrelated kindreds with AD-HIES due to DN IL6ST mutations. We identified seven different truncating mutations, one of which was recurrent. The mutant alleles encode GP130 receptors bearing the transmembrane domain but lacking both the recycling motif and all four STAT3-recruiting tyrosine residues. Upon overexpression, the mutant proteins accumulate at the cell surface and are loss of function and DN for cellular responses to IL-6, IL-11, LIF, and OSM. Moreover, the patients' heterozygous leukocytes and fibroblasts respond poorly to IL-6 and IL-11. Consistently, patients with STAT3 and IL6ST mutations display infectious and allergic manifestations of IL-6R deficiency, and some of the skeletal abnormalities of IL-11R deficiency. DN STAT3 and IL6ST mutations thus appear to underlie clinical phenocopies through impairment of the IL-6 and IL-11 response pathways.