IL‐4‐induced gene 1 maintains high Tob1 expression that contributes to TCR unresponsiveness in human T helper 17 cells

Human Th17 cells have a limited proliferative capacity compared to other T‐cell subsets. We have shown that human Th17 cells display impaired IL‐2 production due to IL‐4‐induced gene 1 (IL4I1) upregulation. Here, we show that in human Th17 cells, IL4I1 also maintains high levels of Tob1, a member of the Tob/BTG (B‐cell traslocation gene) antiproliferative protein family, which prevents cell‐cycle progression mediated by TCR stimulation. Indeed, Th17 cells exhibited higher levels of Tob1 than Th1 cells in both resting and TCR‐activated conditions. Accordingly, the expression of positive regulators of the cell cycle (cyclin A, B, C, and E and Cdk2), as well as of Skp2, which promotes Tob1 degradation, was lower in Th17 cells than in Th1 cells. Tob1 expression in human Th17 cells correlated with both RAR (retinoic acid receptor)‐related orphan receptor C (RORC) and IL4I1 levels. However, RORC was not directly involved in the regulation of Tob1 expression, whereas IL4I1 silencing in Th17 cells induced a substantial decrease of Tob1 expression. These data suggest that IL4I1 upregulation in human Th17 cells limits their TCR‐mediated expansion not only by blocking the molecular pathway involved in the activation of the IL‐2 promoter, but also by maintaining high levels of Tob1, which impairs entry into the cell cycle.     

Intestinal transplantation: a review

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. Intestinal transplantation is now recognized as a treatment for patients who develop complications of parenteral nutrition and in whom attempts at intestinal rehabilitation have failed. Patients with parenteral nutrition related liver disease will require a liver graft typically part of a multivisceral transplant. Isolated intestinal transplants are more commonly performed in adults while multivisceral transplants are most commonly performed in infants. Isolated intestinal transplants have the best short-term outcome, with over 80?% survival at 1?year. Patients requiring multivisceral transplants have a high rate of attrition with a 1?year survival less than 70?%. Prognostic factors for a poor outcome include patient hospitalization at the time of transplant and donor age greater than 40?years while systemic sepsis and acute rejection are the major determinant of early postoperative outcome. For patients surviving the first year the outcome of transplantation of the liver in addition to intestine affords some survival advantage though long-term outcome does not yet match other abdominal organs. Outcomes for intestinal retransplantation are poor as a result of immunology and patient debility. Overall intestinal transplantation continues to develop and is a clear indication with cost and quality of life advantages in patients with intestinal failure that do not remain stable on parenteral nutrition.     

Crystal structure of a eukaryotic zinc-dependent histone deacetylase, human HDAC8, complexed with a hydroxamic acid inhibitor

Histone deacetylases (HDACs) are a family of enzymes involved in the regulation of gene expression, DNA repair, and stress response. These processes often are altered in tumors, and HDAC inhibitors have had pronounced antitumor activity with promising results in clinical trials. Here, we report the crystal structure of human HDAC8 in complex with a hydroxamic acid inhibitor. Such a structure of a eukaryotic zinc-dependent HDAC has not be described previously. Similar to bacterial HDAC-like protein, HDAC8 folds in a single alpha/beta domain. The inhibitor and the zinc-binding sites are similar in both proteins. However, significant differences are observed in the length and structure of the loops surrounding the active site, including the presence of two potassium ions in HDAC8 structure, one of which interacts with key catalytic residues. CD data suggest a direct role of potassium in the fold stabilization of HDAC8. Knockdown of HDAC8 by RNA interference inhibits growth of human lung, colon, and cervical cancer cell lines, highlighting the importance of this HDAC subtype for tumor cell proliferation. Our findings open the way for the design and development of selective inhibitors of HDAC8 as possible antitumor agents.     

Sleep architecture and NREM alterations in children and adolescents with Asperger syndrome

STUDY OBJECTIVES: To analyze sleep in children with Asperger syndrome (AS) by means of standard sleep questionnaires, to evaluate sleep architecture and NREM sleep alterations by means of cyclic alternating pattern (CAP) and to correlate objective sleep parameters with cognitive behavioral measures. DESIGN: Cross-sectional study involving validated sleep questionnaires, neuropsychological scales, and PSG recording. SETTING: Sleep medicine center. PARTICIPANTS: Eight children with AS, 10 children with autism, and 12 healthy control children. INTERVENTIONS: N/A MEASUREMENTS AND RESULTS: Children with AS had a higher prevalence of problems of initiating sleep and daytime sleepiness. Sleep architecture parameters showed minor differences between the 3 groups. CAP parameters showed an increased percentage of A1 and a decreased percentage of A2 subtypes in subjects with AS vs. controls. All A subtype indexes (number per hour of NREM sleep) were decreased, mostly in sleep stage 2 but not in SWS. With respect to children with autism, subjects with AS showed increased CAP rate in SWS and A1 percentage. In subjects with AS, verbal IQ had a significant positive correlation with total CAP rate and CAP rate in SWS and with global and SWS A1 index. The percentage of A2 negatively correlated with full scale IQ, verbal and performance IQ. CBCL total score correlated positively with CAP rate and A1 index while externalizing score correlated negatively with A3%. CONCLUSIONS: This study shows peculiar CAP modifications in children with AS and represents an attempt to correlate the quantification of sleep EEG oscillations with the degree of mental ability/disability.     

Cholesterol crystallization in human atherosclerosis is triggered in smooth muscle cells during the transition from fatty streak to fibroatheroma

Recent studies have shown that in addition to being major constituents of the atheromatous core, solid cholesterol crystals (CCs) promote atherosclerotic lesion development and rupture by causing mechanical damage and exerting cytotoxic and pro‐inflammatory effects. These findings suggest that targeting CCs might represent a therapeutic strategy for plaque stabilization. However, little is known about how cholesterol crystallization is initiated in human atherothrombotic disease. Here, we investigated these mechanisms. We performed a thorough immunohistological analysis of non‐embedded, minimally processed human aortic tissues, combining polarized light and fluorescence microscopy. We found that CC formation was initiated during the fatty streak to fibroatheroma transition in tight association with the death of intralesional smooth muscle cells (SMCs). Cholesterol‐loaded human SMCs were capable of producing CCs in vitro, a process that was enhanced by type I collagen and by inhibition of autophagy and cholesterol esterification. The fibrous transition, which was characterized by increased type I collagen expression, was associated with changes in the expression of autophagy and cholesterol flux‐related genes, including a decrease in the autophagic adapter p62 and an increase in the cholesterol intracellular transporter Niemann–Pick C1. Collagen was identified as a potent inducer of these changes in SMCs. Collagen‐induced changes in cholesterol metabolism and autophagy flux in smooth muscle foam cells at the fibrolipid transition likely contribute to initiate cholesterol crystallization in human atherosclerosis. Also, our data are in support of a protective role of autophagy against CC formation. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

The CDC2 I-G-T haplotype associated with the APOE epsilon4 allele increases the risk of sporadic Alzheimer's disease in Sicily

The cell division cycle 2 (CDC2) gene is a candidate susceptibility gene for Alzheimer's disease (AD). We investigated the CDC2 genotype, and allele and haplotype frequencies in AD patients and matched controls, distinguishing between apolipoprotein E (APOE) epsilon4 allele carriers and non-carriers. APOE epsilon4 is an established predictor of AD risk. APOE and CDC2 genotypes were examined in 109 sporadic AD patients and in 110 healthy age- and sex-matched controls from Sicily. The epsilon4 allele of APOE was predictive of AD risk in our study group (odds ratio: 5.37, 95% CI 2.77-10.41; P<0.0001). Genotype and allele frequencies of the three tested CDC2 polymorphisms (Ex6+7I/D, Ex7-15 G>A, Ex7-14 T>A) were not significantly different between AD patients and controls. However, a significant different distribution of a specific CDC2 haplotype (I-G-T) was found between AD patients and controls when analyzing APOE epsilon4-positive subjects (P=0.0288). Moreover, the combined presence of the I-G-T haplotype and the epsilon4 allele almost doubled the risk of AD (odds ratio: 10.09, 95% CI 3.88-26.25; P<0.0001) compared to carriers of epsilon4 alone. This study suggests that the I-G-T haplotype of the CDC2 gene increases the risk of AD in APOE epsilon4 carriers.     

Searching for a marker of REM sleep behavior disorder: submentalis muscle EMG amplitude analysis during sleep in patients with narcolepsy/cataplexy

STUDY OBJECTIVES: To evaluate the amplitude of submentalis muscle EMG activity during sleep in patients with narcolepsy/cataplexy with or without REM sleep behavior disorder (RBD). DESIGN: Observational study with consecutive recruitment. SETTINGS: Sleep laboratory. PATIENTS: Thirty-four patients with narcolepsy/cataplexy and 35 age-matched normal controls. MEASUREMENTS AND RESULTS: Half the patients (17 subjects) had a clinical and video polysomnographic diagnosis of RBD. The average amplitude of the rectified submentalis muscle EMG signal was used to assess muscle atonia, and the new REM sleep Atonia Index was computed. Chin muscle activations were detected and their duration and interval analyzed. REM sleep Atonia Index was lower in both patient groups (with narcolepsy patients with RBD showing the lowest values) with respect to controls, and it did not correlate with age as it did in controls. The total number of chin EMG activations was significantly higher in both patient groups than controls. No significant differences were found between the two groups of patients, although more chin EMG activations were noted in narcolepsy patients with RBD than those without. CONCLUSIONS: Elevated muscle activity during REM sleep is the only polysomnographic marker of RBD. This study shows that polysomnographically evident RBD is present in many patients with narcolepsy/ cataplexy. This condition might be specific to narcolepsy/cataplexy, reflecting a peculiar form of REM sleep related motor dyscontrol (i.e., status dissociatus), paving the way to enacting dream behaviors, and correlated with the specific neurochemical and neuropathological substrate of narcolepsy/cataplexy.     

Experimental Calcification of the Myocardium: Ultrastructural and Histochemical Investigations

Focal areas of calcification are frequent in rat myocardium 30 and 60 days after administration of dihydrotachysterol. These areas are PAS-positive, stain deeply with alcian blue and show high affinity for colloidal iron. Calcification is almost completely confined to intracellular structures. Small clusters of needle-shaped crystals are first found in apparently undamaged mitochondria in undamaged myocardial cells. When all the mitochondria are calcified, the cell degenerates, and inorganic crystals are laid down in relationship with its myofilaments. In other myocardial cells, clusters of amorphous or finely granular inorganic substance are found in both mitochondria and myofibrils. Both structures show signs of advanced degeneration. Inorganic substance has only occasionally been found within the structures of the sarcoplasmic reticulum. These structures do not seem to be involved in myocardial calcification under the present experimental conditions. Calcification of myocardial cells gives rise to a cellular reaction. Many macrophagic cells surround the calcified areas, which are rapidly reabsorbed. The present results show that myocardial mitochondria are actively engaged in controlling the intracellular concentration and movement of calcium ions. Their role in the myocardial contraction-relaxation cycle and the possible mechanism of myocardial calcification are discussed.