Pseudouridylation defect due to DKC1 and NOP10 mutations causes nephrotic syndrome with cataracts, hearing impairment, and enterocolitis.

RNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in DKC1, NOP10, or NHP2 cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition. Here, we report a phenotype comprising nephrotic syndrome, cataracts, sensorineural deafness, enterocolitis, and early lethality in two pedigrees: males with DKC1 p.Glu206Lys and two children with homozygous NOP10 p.Thr16Met. Females with heterozygous DKC1 p.Glu206Lys developed cataracts and sensorineural deafness, but nephrotic syndrome in only one case of skewed X-inactivation. We found telomere attrition in both pedigrees, but no mucocutaneous abnormalities suggestive of DC. Both mutations fall at the dyskerin-NOP10 binding interface in a region distinct from those implicated in DC, impair the dyskerin-NOP10 interaction, and disrupt the catalytic pseudouridylation site. Accordingly, we found reduced pseudouridine levels in the ribosomal RNA (rRNA) of the patients. Zebrafish dkc1 mutants recapitulate the human phenotype and show reduced 18S pseudouridylation, ribosomal dysregulation, and a cell-cycle defect in the absence of telomere attrition. We therefore propose that this human disorder is the consequence of defective snoRNP pseudouridylation and ribosomal dysfunction.

Effects of non-steroidal anti-inflammatory drugs and other eicosanoid pathway modifiers on antiviral and allergic responses: EAACI task force on eicosanoids consensus report in times of COVID-19.

Non-steroidal anti-inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti-inflammatory, antipyretic, and analgesic effects are applied against symptoms of respiratory infections, including SARS-CoV-2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID-19 also revealed the gaps in our understanding of their mechanism of action, selectivity, and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs-exacerbated respiratory disease (NERD). In this context, the consensus report summarizes currently available knowledge, novel discoveries, and controversies regarding the use of NSAIDs in COVID-19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID-19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarize the major knowledge gaps and unmet needs in current eicosanoid research.

Current perspective on eicosanoids in asthma and allergic diseases: EAACI Task Force consensus report, part I.

Eicosanoids are biologically active lipid mediators, comprising prostaglandins, leukotrienes, thromboxanes, and lipoxins, involved in several pathophysiological processes relevant to asthma, allergies, and allied diseases. Prostaglandins and leukotrienes are the most studied eicosanoids and established inducers of airway pathophysiology including bronchoconstriction and airway inflammation. Drugs inhibiting the synthesis of lipid mediators or their effects, such as leukotriene synthesis inhibitors, leukotriene receptors antagonists, and more recently prostaglandin D2 receptor antagonists, have been shown to modulate features of asthma and allergic diseases. This review, produced by an European Academy of Allergy and Clinical Immunology (EAACI) task force, highlights our current understanding of eicosanoid biology and its role in mediating human pathology, with a focus on new findings relevant for clinical practice, development of novel therapeutics, and future research opportunities.

A rare case of polyglandular autoimmune syndrome type IIIc with primary antibody failure.

Primary antibody deficiency syndromes are a rare group of disorders present at any age, with complex polygenic disorders. We report the forth case of polyglandular autoimmune syndrome (PAS) type IIIc worldwide with complex clinical features and no family history of endocrine disorders or primary immunodeficiencies. Our patient, a 44-year-old Caucasian female was diagnosed with PAS type IIIc due to the presence of autoimmune thyroiditis, autoimmune alopecia diffusa and primary ovarian insufficiency, associated with lymphoproliferative disease and primary antibody failure. Treatment included lifelong intravenous immunoglobulin, supplements and antibiotics. The clinical complexity and rare occurrence made it challenging to determine diagnosis and provide better treatment for the patient. The current case provides an insight of the challenges to determine primary antibody failure signs in the presence of PAS which will further help to determine diagnosis and therapeutic treatment for PAS patients.

T-Cell Subsets in Rheumatoid Arthritis Patients on Long-Term Anti-TNF or IL-6 Receptor Blocker Therapy.

Data on the impact of biological therapies on the T-cell phenotype in rheumatoid arthritis are limited. Here, we prospectively measured the percentages of 15 circulating T-cell subtypes using flow cytometry. We obtained transversal and longitudinal data in 30 anti-TNF responders, 19 secondary anti-TNF nonresponders, and 43 IL-6R antagonist responders, before, 8 weeks and at least 6 months after biological therapy. Untreated RA patients and healthy controls were also included. The important findings are the following: (1) the proportion of regulatory T-cells (Tregs) which are decreased in untreated RA patients becomes normal in all long-term-treated groups; (2) in anti-TNF responders as well as in nonresponders, the frequencies of naïve CD4+ and CD8+ cells are lower, whereas those of proinflammatory Th1, Th2, and Th17 cells and HLA-DR+-activated cells are higher than those in untreated RA or healthy controls; (3) in IL-6R responders, Th1 proportion is decreased, while that of Th2 and Th17 is increased as compared to that in anti-TNF-treated patients and controls; (4) pending confirmation, a CD4CD69 ratio < 2.43 at baseline, could be useful to predict a good therapeutic response to anti-TNF therapy. This study provides comprehensive information regarding the long-term impacts of those biological therapies on the ecotaxis of T-cells in RA. The ClinicalTrials.gov registration number of our study is NCT03266822.

Expression of lymphocyte activation markers of preterm neonates is associated with perinatal complications.

BACKGROUND: Inappropriate activation of T lymphocytes plays an important role in perinatal complications. However, data on T lymphocyte activation markers of preterm infants is scarce. We investigated the association between gender, gestational and postnatal age, preeclampsia (PE), premature rupture of membranes (PROM) as well as prenatal steroid treatment (PS) and the frequency of activated T lymphocyte subsets (HLA-DR+, CD69+, CD25+, CD62L+) and major T lymphocyte subpopulations (CD4, CD8, Th1, Th2, naïve, memory) in peripheral blood during the first postnatal week in preterm infants. RESULTS: Cord blood and peripheral blood samples were collected from 43 preterm infants on the 1st, 3rd, and 7th days of life. We assessed the frequency of the above T lymphocyte subsets using flow cytometry. The 'mixed effect model' was used to analyze the effects of clinical parameters on T lymphocyte markers. The frequency of CD25+ T lymphocytes was higher in PROM. The frequency of CD4+ and CD8+ cells and the CD4+/CD8+ cell ratio was decreased in PE. The frequency of CD62L+ T lymphocytes was higher in male compared with female infants. PS did not affect the frequency of the investigated markers. CD4+ CD25+ cells had a lower frequency at birth than on day 7. Th2 lymphocytes had a lower frequency on postnatal days 1 and 3 when compared to day 7. CONCLUSIONS: Our observations indicate that alterations affecting the expression of T lymphocyte activation markers are associated with the above factors and may play a role in the development of perinatal complications.

Specific T-Cell Subsets Can Predict the Efficacy of Anti-TNF Treatment in Inflammatory Bowel Diseases.

The effect of TNF-blockers on T-lymphocyte subsets is largely unknown in inflammatory bowel diseases (IBDs). The aim of the present study was to analyze the prevalence of T-cell subtypes and their correlation to therapeutic response. Sixty-eight patients with Crohn's disease (CD), 46 with ulcerative colitis (UC) were enrolled. (1) The clinical course was followed after the initiation of TNF-blockers (prospective study). (2) The immunophenotype was also compared between long-term anti-TNF treated-responders and non-responders (cross-sectional study). The results were compared with those of therapy-naïve patients with active disease and those in remission with non-biological immunosuppressive therapy, and with healthy controls. Fourteen subtypes of peripheral blood T cells were measured with flow cytometry. The prevalence of Th2 and Th17 cells, of HLA-DR- and CD69-positive CD4 and CD8 cells, was higher, whereas the percentage of CD45RA-positive CD4 and CD8 cells was lower in both IBDs than in controls. CD8CD69 cell frequency was lower in remission, and decreased during anti-TNF therapy in CD responders. CD8CD45RO memory cells had higher prevalence in UC non-responders than in those starting anti-TNF. CD4CD45RO percentage < 49.05 at the initiation of TNF-blockers was predictive of a subsequent therapeutic response in CD, and Th2 and Th17 prevalence correlated with the duration of remission on TNF-blockers in UC. This study provided a detailed description of the T-cell composition in IBDs. CD8CD69 prevalence may be an activity marker in CD, and CD4CD45RO, Th2 and Th17 levels could be predictive for a therapeutic response to anti-TNF.

A New Cerkl Mouse Model Generated by CRISPR-Cas9 Shows Progressive Retinal Degeneration and Altered Morphological and Electrophysiological Phenotype.

Purpose: Close to 100 genes cause retinitis pigmentosa, a Mendelian rare disease that affects 1 out of 4000 people worldwide. Mutations in the ceramide kinase-like gene (CERKL) are a prevalent cause of autosomal recessive cause retinitis pigmentosa and cone-rod dystrophy, but the functional role of this gene in the retina has yet to be fully determined. We aimed to generate a mouse model that resembles the phenotypic traits of patients carrying CERKL mutations to undertake functional studies and assay therapeutic approaches. Methods: The Cerkl locus has been deleted (around 97 kb of genomic DNA) by gene editing using the CRISPR-Cas9 D10A nickase. Because the deletion of the Cerkl locus is lethal in mice in homozygosis, a double heterozygote mouse model with less than 10% residual Cerkl expression has been generated. The phenotypic alterations of the retina of this new model have been characterized at the morphological and electrophysiological levels. Results: This CerklKD/KO model shows retinal degeneration, with a decreased number of cones and progressive photoreceptor loss, poorly stacked photoreceptor outer segment membranes, defective retinal pigment epithelium phagocytosis, and altered electrophysiological recordings in aged retinas. Conclusions: To our knowledge, this is the first Cerkl mouse model to mimic many of the phenotypic traits, including the slow but progressive retinal degeneration, shown by human patients carrying CERKL mutations. This useful model will provide unprecedented insights into the retinal molecular pathways altered in these patients and will contribute to the design of effective treatments.

Effects of caffeine and phosphodiesterase inhibitors on activation of neonatal T lymphocytes.

Caffeine and selective PDE inhibitors are widely used in clinical management of preterm and term neonates. However, little is known about how these compounds interact with the neonatal adaptive immune system. We aimed to describe the effects of caffeine, milrinone and sildenafil on the activation and cytokine production of T cells from umbilical cord blood (UCB) compared to adult peripheral blood (APB). We isolated mononuclear cells from 10 APB and 6 UCB samples. We assessed intracellular cytokine production (IFN-γ, IL-2, IL-4, IL-6, IL-17) of stimulated CD4 cells and parameters of calcium influx and ROS production following treatment with caffeine, milrinone, sildenafil, dbcAMP or a specific A2A receptor antagonist, ZM241385 using flow cytometry. In ABP, only ZM241385 caused a 1.14-fold increase in calcium influx, while all compounds increased calcium influx in UCB. This effect was more pronounced in case of caffeine (1.41-fold) and dbcAMP (1.3-fold) compared to milrinone (1.22-fold), sildenafil (1.23-fold) or ZM241385 (1.23-fold). Intracellular levels of the studied cytokines were unaffected by the applied compounds in both APB and UCB samples. Caffeine increases calcium influx upon activation in neonatal T lymphocytes to a larger extent than milrinone or sildenafil. This effect appears to be mediated primarily via increased cAMP levels rather than A2A receptor inhibition. Overall, the application of caffeine, sildenafil or milrinone does not appear to have immunosuppressive effects on neonatal T cells.

Immune cell subsets, cytokine and cortisol levels during the first week of life in neonates born to pre-eclamptic mothers.

PROBLEM: To address the hypothesis that pre-eclampsia (PE) impacts the fetal immune system, we investigated the prevalence of distinct immune cell subsets along with plasma cortisol and cytokine levels in pre-term newborns of PE mothers. METHOD OF STUDY: Cord blood and peripheral blood samples on the 1st, 3rd and 7th postnatal days of life were collected from 14 pre-term infants affected by PE and 14 non-PE pregnancies. We measured plasma cortisol and cytokine levels with immunoassays and assessed the prevalence of T, NK and DC subsets using flow cytometry. RESULTS: The prevalence of CD4+ cells was lower in PE infants, while that of memory T cells was higher. Myeloid DCs had a lower prevalence in PE neonates. Cytokine and cortisol levels were lower in PE neonates. CONCLUSION: Our observations show that PE pregnancies are associated with altered newborn immune status during the first week of life.

Plasma vitamin D levels at birth and immune status of preterm infants.

BACKGROUND: Vitamin D has an important immunomodulatory role. We investigated whether vitamin D levels at birth may associate with immune status in preterm infants. METHODS: Cord blood samples were collected from 28 preterm infants born ≤30 weeks of gestation. Infants were divided into groups below and above median vitamin D level. We measured plasma cortisol and cytokine levels and also assessed the peripheral prevalence of distinct immune cell subsets using flow cytometry. The mixed effect model was used to analyse the effects of vitamin D, plasma cortisol levels and gestational age on cytokine levels and immune phenotype. RESULTS: Vitamin D level in our cohort was 23.3 [9.9-45.4]ng/ml (median [range]). In infants with vitamin D level below the median the prevalence of CD4+ CXCR3+ (Th1) and CD8+ CXCR3+ cell subsets was higher, while the prevalence of CD4+ CCR4+ (Th2), CD8+ CCR4+ and plasmacytoid dendritic cell (pDC) subsets was lower than in those with vitamin D level above median. pDCs and Th2 lymphocytes were the only cell subsets which were only influenced by vitamin D levels, but not by plasma cortisol and gestational age. No association between vitamin D level and any of the tested plasma cytokine levels was detected. CONCLUSIONS: Vitamin D levels may together with cortisol levels and gestational age have an effect on Th1/Th2 balance and the prevalence of plasmocytoid dendritic cells in the preterm newborn.

High transcriptional complexity of the retinitis pigmentosa CERKL gene in human and mouse.

PURPOSE: To shed light on the pathogenicity of the mutations in the retinitis pigmentosa gene CERKL, the authors aimed to characterize its transcriptional repertoire and focused on the use of distinct promoters and alternative splicing in human and mouse tissues. METHODS: In silico genomic and transcriptomic computational customized analysis, combined with experimental RT-PCRs on different human and murine tissues and cell lines and immunohistochemistry, have been used to characterize the transcriptional spectrum of CERKL. In the mouse retina, Cerkl is detected primarily in ganglion cells and cones but can also be observed in rods. Cerkl is mainly cytosolic. It localizes in the outer segments of photoreceptors and in the perinuclear regions of some cells. RESULTS: An unexpected multiplicity of CERKL transcriptional start sites (four in each species) plus a high variety of alternative splicing events primarily affecting the 5' half of the gene generate >20 fully validated mRNA isoforms in human and 23 in mouse. Moreover, several translational start sites, compatible with a wide display of functional domains, contribute to the final protein complexity. CONCLUSIONS: This combined approach of in silico and experimental characterization of the CERKL gene provides a comprehensive picture of the species-specific transcriptional products in the retina, underscores highly tuned gene regulation in different tissues, and establishes a framework for the study of CERKL genotype-phenotype correlations.