Type 1 interferon-inducible gene expression in QuantiFERON Gold TB-positive uveitis: A tool to stratify a high versus low risk of active tuberculosis?

QuantiFERON-Gold TB (QFT)-positive patients with undetermined cause of uveitis are problematic in terms of whether to diagnose and treat them for tuberculosis (TB). Here, we investigated whether peripheral blood expression of type 1 interferon (IFN)-inducible genes may be of use to stratify QFT-positive patients with uveitis into groups of high versus low risk of having active TB-associated uveitis. We recruited all new uveitis patients in Cipto Mangunkusumo Hospital, Jakarta, Indonesia for one year. We included 12 patients with uveitis and clinically diagnosed active pulmonary TB, 58 QFT-positive patients with uveitis of unknown cause, 10 newly diagnosed sputum-positive active pulmonary TB patients without uveitis and 23 QFT-negative healthy controls. Expression of 35 type 1 IFN-inducible genes was measured in peripheral blood cells from active pulmonary TB patients without uveitis and healthy controls. Differentially expressed genes were identified and used for further clustering analyses of the uveitis groups. A type-1 IFN gene signature score was calculated and the optimal cut-off value for this score to differentiate active pulmonary TB from healthy controls was determined and applied to QFT-positive patients with uveitis of unknown cause. Ten type 1 IFN-inducible genes were differentially expressed between active pulmonary TB and healthy controls. Expression of these 10 genes in QFT-positive patients with uveitis of unknown cause revealed three groups: 1); patients resembling active pulmonary TB, 2); patients resembling healthy controls, and 3); patients displaying an in-between gene expression pattern. A type 1 IFN gene signature score ≥5.61 displayed high sensitivity (100%) and specificity (91%) for identification of active TB. Application of this score to QFT-positive patients with uveitis of unknown cause yielded two groups with expected different likelihood (high vs. low) of having active-TB uveitis, and therefore may be useful in clinical management decisions

CHCHD10 variants in amyotrophic lateral sclerosis: where Is the evidence?

Objective: After the initial report of a CHCHD10 mutation in mitochondrial disease with features resembling amyotrophic lateral sclerosis (ALS), CHCHD10 mutations have been considered to be a frequent cause for ALS. However, the exact pathogenicity and clinical significance of these mutations remain unclear. Here, we aimed to determine the role of CHCHD10 mutations in ALS. Methods: We analyzed 4,365 whole genome sequenced ALS patients and 1,832 controls from 7 different countries and examined all nonsynonymous single nucleotide variants in CHCHD10. These were tested for association with ALS, independently and in aggregate using several genetic burden tests (including sequence kernel association test [SKAT], optimal unified test [SKAT-O], and Firth logistic regression). Results: We identified 3 new variants in cases, but only 1 was ALS-specific. lso, 1 control-specific mutation was identified. There was no increased burden of rare coding mutations among ALS patients compared to controls (p=0.86, p=0.86, and p=0.88 for SKAT, SKAT-O, and Firth, respectively). The few carriers with potential pathogenic CHCHD10 mutations exhibited a slowly progressive ALS-like phenotype with atypical features such as myopathy and deafness. Interpretation: CHCHD10 mutations seem to be a far less prevalent cause of pure ALS than previously suggested, and instead appear related to more complex phenotypes. There appears to be insufficient evidence for the pathogenicity of most previously reported variants in pure ALS. This study shows that routine testing for CHCHD10 mutations in pure ALS is not recommended and illustrates the importance of sufficient genetic and functional evidence in establishing pathogenicity of genetic variants

Project MinE: study design and pilot analyses of a large-scale whole-genome sequencing study in amyotrophic lateral sclerosis

The most recent genome-wide association study in amyotrophic lateral sclerosis (ALS) demonstrates a disproportionate contribution from low-frequency variants to genetic susceptibility to disease. We have therefore begun Project MinE, an international collaboration that seeks to analyze whole-genome sequence data of at least 15 000 ALS patients and 7500 controls. Here, we report on the design of Project MinE and pilot analyses of successfully sequenced 1169 ALS patients and 608 controls drawn from the Netherlands. As has become characteristic of sequencing studies, we find an abundance of rare genetic variation (minor allele frequency < 0.1%), the vast majority of which is absent in public datasets. Principal component analysis reveals local geographical clustering of these variants within The Netherlands. We use the whole-genome sequence data to explore the implications of poor geographical matching of cases and controls in a sequence-based disease study and to investigate how ancestry-matched, externally sequenced controls can induce false positive associations. Also, we have publicly released genome-wide minor allele counts in cases and controls, as well as results from genic burden tests

Dual role of cerebral blood flow in regional brain temperature control in the healthy newborn infant.

Small shifts in brain temperature after hypoxia-ischaemia affect cell viability. The main determinants of brain temperature are cerebral metabolism, which contributes to local heat production, and brain perfusion, which removes heat. However, few studies have addressed the effect of cerebral metabolism and perfusion on regional brain temperature in human neonates because of the lack of non-invasive cot-side monitors. This study aimed (i) to determine non-invasive monitoring tools of cerebral metabolism and perfusion by combining near-infrared spectroscopy and echocardiography, and (ii) to investigate the dependence of brain temperature on cerebral metabolism and perfusion in unsedated newborn infants. Thirty-two healthy newborn infants were recruited. They were studied with cerebral near-infrared spectroscopy, echocardiography, and a zero-heat flux tissue thermometer. A surrogate of cerebral blood flow (CBF) was measured using superior vena cava flow adjusted for cerebral volume (rSVC flow). The tissue oxygenation index, fractional oxygen extraction (FOE), and the cerebral metabolic rate of oxygen relative to rSVC flow (CMRO2 index) were also estimated. A greater rSVC flow was positively associated with higher brain temperatures, particularly for superficial structures. The CMRO2 index and rSVC flow were positively coupled. However, brain temperature was independent of FOE and the CMRO2 index. A cooler ambient temperature was associated with a greater temperature gradient between the scalp surface and the body core. Cerebral oxygen metabolism and perfusion were monitored in newborn infants without using tracers. In these healthy newborn infants, cerebral perfusion and ambient temperature were significant independent variables of brain temperature. CBF has primarily been associated with heat removal from the brain. However, our results suggest that CBF is likely to deliver heat specifically to the superficial brain. Further studies are required to assess the effect of cerebral metabolism and perfusion on regional brain temperature in low-cardiac output conditions, fever, and with therapeutic hypothermia

The suprachiasmatic nucleus controls circadian energy metabolism and hepatic insulin sensitivity.

Disturbances in the circadian system are associated with the development of type 2 diabetes mellitus. Here, we studied the direct contribution of the suprachiasmatic nucleus (SCN), the central pacemaker in the circadian system, in the development of insulin resistance. Exclusive bilateral SCN lesions in male C57Bl/6J mice, as verified by immunochemistry, showed a small but significant increase in body weight (+17%), which was accounted for by an increase in fat mass. In contrast, mice with collateral damage to the ventromedial hypothalamus and paraventricular nucleus showed severe obesity and insulin resistance. Mice with exclusive SCN ablation revealed a loss of circadian rhythm in activity, oxygen consumption, and food intake. Hyperinsulinemic-euglycemic clamp analysis 8 weeks after lesioning showed that the glucose infusion rate was significantly lower in SCN lesioned mice compared with sham-operated mice (-63%). Although insulin potently inhibited endogenous glucose production (-84%), this was greatly reduced in SCN lesioned mice (-7%), indicating severe hepatic insulin resistance. Our data show that SCN malfunctioning plays an important role in the disturbance of energy balance and suggest that an absence of central clock activity, in a genetically intact animal, may lead to the development of insulin resistance

Two human homologs of Rad23 are functionally interchangeable in complex formation and stimulation of XPC repair activity.

XPC-hHR23B protein complex is specifically involved in nucleotide excision repair (NER) of DNA lesions on transcriptionally inactive sequences as well as the nontranscribed strand of active genes. Here we demonstrate that not only highly purified recombinant hHR23B (rhHR23B) but also a second human homolog of the Saccharomyces cerevisiae Rad23 repair protein, hHR23A, stimulates the in vitro repair activity of recombinant human XPC (rhXPC), revealing functional redundancy between these human Rad23 homologs. Coprecipitation experiments with His-tagged rhHR23 as well as sedimentation velocity analysis showed that both rhHR23 proteins in vitro reconstitute a physical complex with rhXPC. Both complexes were more active than free rhXPC, indicating that complex assembly is required for the stimulation. rhHR23B was shown to stimulate an early stage of NER at or prior to incision. Furthermore, both rhHR23 proteins function in a defined NER system reconstituted with purified proteins, indicating direct involvement of hHR23 proteins in the DNA repair reaction via interaction with XPC