Aberrant cholesterol metabolic signaling impairs antitumor immunosurveillance through natural killer T cell dysfunction in obese liver.

Obesity is a major risk factor for cancers including hepatocellular carcinoma (HCC) that develops from a background of non-alcoholic fatty liver disease (NAFLD). Hypercholesterolemia is a common comorbidity of obesity. Although cholesterol biosynthesis mainly occurs in the liver, its role in HCC development of obese people remains obscure. Using high-fat high-carbohydrate diet-associated orthotopic and spontaneous NAFLD-HCC mouse models, we found that hepatic cholesterol accumulation in obesity selectively suppressed natural killer T (NKT) cell-mediated antitumor immunosurveillance. Transcriptome analysis of human liver revealed aberrant cholesterol metabolism and NKT cell dysfunction in NAFLD patients. Notably, cholesterol-lowering rosuvastatin restored NKT expansion and cytotoxicity to prevent obesogenic diet-promoted HCC development. Moreover, suppression of hepatic cholesterol biosynthesis by a mammalian target of rapamycin (mTOR) inhibitor vistusertib preceded tumor regression, which was abolished by NKT inactivation but not CD8+ T cell depletion. Mechanistically, sterol regulatory element-binding protein 2 (SREBP2)-driven excessive cholesterol production from hepatocytes induced lipid peroxide accumulation and deficient cytotoxicity in NKT cells, which were supported by findings in people with obesity, NAFLD and NAFLD-HCC. This study highlights mTORC1/SREBP2/cholesterol-mediated NKT dysfunction in the tumor-promoting NAFLD liver microenvironment, providing intervention strategies that invigorating NKT cells to control HCC in the obesity epidemic.

Rotavirus is frequent among adults hospitalised for acute gastroenteritis.

INTRODUCTION: Rotavirus infection is the most common aetiology of acute gastroenteritis (AGE) among young children. In adults, diagnostics focus mainly on bacterial causes, though recent studies suggest that rotavirus is a frequent agent. The aim of this study was to examine the proportion of rotavirus in adults hospitalised with AGE and to identify possible predictors. METHODS: During a 24-month period from 1 May 2010 adults (> 15 years) with AGE admitted to one of four hospitals in the Central Denmark Region were examined for rotavirus with VIKIA Rota-Adeno rapid test in addition to routine culture for bacterial pathogens. RESULTS: A total of 265 adult patients were included. 9.4% tested positive for rotavirus. Enteropathogenic bacteria were found in 24.5% of the cases. In the majority of cases (62.3%), no pathogen was found. Overall, rotavirus was the second-most frequent pathogen, exceeded only by Campylobacter spp. Immunosuppression and a C-reactive protein (CRP) below 50 mg/l (0-8 mg/l) were associated with rotavirus. The seasonality of rotavirus differed markedly from that of bacterial gastroenteritis. CONCLUSION: Rotavirus is the second-most frequently identified pathogen in adults hospitalised with AGE. Close contact to children or travel activity does not predict rotavirus gastroenteritis, but immunosuppression and a CRP below 50 mg/l do. The seasonality of rotavirus differs from that of bacterial gastroenteritis, making rotavirus the most frequently identified cause of AGE in adults admitted to hospital in the colder months. FUNDING: The trial was funded by an unrestricted grant from Sanofi Pasteur MSD. TRIAL REGISTRATION: not relevant.

Immunodominant fragments of myelin basic protein initiate T cell-dependent pain.

BACKGROUND: The myelin sheath provides electrical insulation of mechanosensory Aß-afferent fibers. Myelin-degrading matrix metalloproteinases (MMPs) damage the myelin sheath. The resulting electrical instability of Aß-fibers is believed to activate the nociceptive circuitry in Aß-fibers and initiate pain from innocuous tactile stimulation (mechanical allodynia). The precise molecular mechanisms, responsible for the development of this neuropathic pain state after nerve injury (for example, chronic constriction injury, CCI), are not well understood. METHODS AND RESULTS: Using mass spectrometry of the whole sciatic nerve proteome followed by bioinformatics analyses, we determined that the pathways, which are classified as the Infectious Disease and T-helper cell signaling, are readily activated in the nerves post-CCI. Inhibition of MMP-9/MMP-2 suppressed CCI-induced mechanical allodynia and concomitant TNF-α and IL-17A expression in nerves. MMP-9 proteolysis of myelin basic protein (MBP) generated the MBP84-104 and MBP68-86 digest peptides, which are prominent immunogenic epitopes. In agreement, the endogenous MBP69-86 epitope co-localized with MHCII and MMP-9 in Schwann cells and along the nodes of Ranvier. Administration of either the MBP84-104 or MBP68-86 peptides into the naïve nerve rapidly produced robust mechanical allodynia with a concomitant increase in T cells and MHCII-reactive cell populations at the injection site. As shown by the genome-wide expression profiling, a single intraneural MBP84-104 injection stimulated the inflammatory, immune cell trafficking, and antigen presentation pathways in the injected naïve nerves and the associated spinal cords. Both MBP84-104-induced mechanical allodynia and characteristic pathway activation were remarkably less prominent in the T cell-deficient athymic nude rats. CONCLUSIONS: These data implicate MBP as a novel mediator of pain. Furthermore, the action of MMPs expressed within 1 day post-injury is critical to the generation of tactile allodynia, neuroinflammation, and the immunodominant MBP digest peptides in nerve. These MBP peptides initiate mechanical allodynia in both a T cell-dependent and -independent manner. In the course of Wallerian degeneration, the repeated exposure of the cryptic MBP epitopes, which are normally sheltered from immunosurveillance, may induce the MBP-specific T cell clones and a self-sustaining immune reaction, which may together contribute to the transition of acute pain into a chronic neuropathic pain state.

Gestión técnica de una unidad de inmunoterapia / Technical gestion in the immunotherapy unit

Antecedentes y objetivos: La administración de inmunoterapia (IT) por vía subcutánea es un tratamiento no exento de riesgos, por lo que su administración debe llevarse a cabo siguiendo estrictos protocolos de actuación. El objetivo del estudio es establecer los criterios de monitorización de los pacientes en una Unidad de Inmunoterapia para reducir el riesgo de aparición de reacciones adversas. Material y métodos: Un total de 378 pacientes diagnosticados de rinitis y/o asma por sensibilización a distintos aeroalergenos (ácaros, pólenes, epitelios y hongos) fueron atendidos en nuestra Unidad durante un período de 15 meses. Todos ellos fueron tratados con extractos estandarizados biológicamente. La monitorización de los enfermos se llevó a cabo con la ayuda de un programa informático (InmunoWin®). Resultados: Se administraron un total de 4.383 dosis. Aparecieron un total de 34 reacciones adversas (0,8 por ciento), de las cuales sólo una fue sistémica (0,02 por ciento). Ésta consistió en un broncoespasmo leve, que se controló inmediatamente. Conclusiones: La correcta monitorización de los pacientes, en la cual la informática juega un papel destacado, en el momento en el que se les administra una dosis de IT, reduce drásticamente el porcentaje de reacciones sistémicas y se demuestra que la IT es un tratamiento seguro cuando se administra bajo las debidas condiciones (AU)