Lupus-associated causal mutation in neutrophil cytosolic factor 2 (NCF2) brings unique insights to the structure and function of NADPH oxidase

Systemic lupus erythematosus (SLE), the prototypic systemic autoimmune disease, is a debilitating multisystem autoimmune disorder characterized by chronic inflammation and extensive immune dysregulation in multiple organ systems, resulting in significant morbidity and mortality. Here, we present a multidisciplinary approach resulting in the identification of neutrophil cytosolic factor 2 (NCF2) as an important risk factor for SLE and the detailed characterization of its causal variant. We show that NCF2 is strongly associated with increased SLE risk in two independent populations: childhood-onset SLE and adult-onset SLE. The association between NCF2 and SLE can be attributed to a single nonsynonymous coding mutation in exon 12, the effect of which is the substitution of histidine-389 with glutamine (H389Q) in the PB1 domain of the NCF2 protein, with glutamine being the risk allele. Computational modeling suggests that the NCF2 H389Q mutation reduces the binding efficiency of NCF2 with the guanine nucleotide exchange factor Vav1. The model predicts that NCF2/H389 residue interacts with Vav1 residues E509, N510, E556, and G559 in the ZF domain of Vav1. Furthermore, replacing H389 with Q results in 1.5 kcal/mol weaker binding. To examine the effect of the NCF2 H389Q mutation on NADPH oxidase function, site-specific mutations at the 389 position in NCF2 were tested. Results show that an H389Q mutation causes a twofold decrease in reactive oxygen species production induced by the activation of the Vav-dependent Fcγ receptor-elicited NADPH oxidase activity. Our study completes the chain of evidence from genetic association to specific molecular function.     

Enhanced cellulose degradation by targeted integration of a cohesin-fused β-glucosidase into the Clostridium thermocellum cellulosome

The conversion of recalcitrant plant-derived cellulosic biomass into biofuels is dependent on highly efficient cellulase systems that produce near-quantitative levels of soluble saccharides. Similar to other fungal and bacterial cellulase systems, the multienzyme cellulosome system of the anaerobic, cellulolytic bacterium Clostridium thermocellum is strongly inhibited by the major end product cellobiose. Cellobiose-induced inhibition can be relieved via its cleavage to noninhibitory glucose by the addition of exogenous noncellulosomal enzyme β-glucosidase; however, because the cellulosome is adsorbed to the insoluble substrate only a fraction of β-glucosidase would be available to the cellulosome. Towards this end, we designed a chimeric cohesin-fused β-glucosidase (BglA-CohII) that binds directly to the cellulosome through an unoccupied dockerin module of its major scaffoldin subunit. The β-glucosidase activity is thus focused at the immediate site of cellobiose production by the cellulosomal enzymes. BglA-CohII was shown to retain cellobiase activity and was readily incorporated into the native cellulosome complex. Surprisingly, it was found that the native C. thermocellum cellulosome exists as a homooligomer and the high-affinity interaction of BglA-CohII with the scaffoldin moiety appears to dissociate the oligomeric state of the cellulosome. Complexation of the cellulosome and BglA-CohII resulted in higher overall degradation of microcrystalline cellulose and pretreated switchgrass compared to the native cellulosome alone or in combination with wild-type BglA in solution. These results demonstrate the effect of enzyme targeting and its potential for enhanced degradation of cellulosic biomass.     

Frequency and Impact of Intensive Care Unit Complications on Moderate-Severe Traumatic Brain Injury: Early Results of the Outcome Prognostication in Traumatic Brain Injury (OPTIMISM) Study

Background

Known predictors of adverse outcomes in patients with moderate-severe TBI (msTBI) explain only a relatively small proportion of patient-related outcomes. The frequency and impact of intensive care unit complications (ICU-COMPL) on msTBI-associated outcomes are poorly understood.

Methods

In 213 consecutive msTBI patients admitted to a Level I Trauma Center neuro trauma ICU, twenty-eight ICU-COMPL (21 medical and 7 neurological) were prospectively collected and adjudicated by group consensus, using pre-defined criteria. We determined frequencies, and explored associations of ICU-COMPL and hospital discharge outcomes using multivariable logistic regression.

Results

The average age of the study sample was 53 years, and the median presenting Glasgow Coma Scale and Injury Severity Scores were 5 and 27, respectively. Hyperglycemia (79 %), fever (62 %), systemic inflammatory response syndrome (60 %), and hypotension requiring vasopressors (42 %) were the four most common medical ICU-COMPL. Herniation (39 %), intracranial rebleed (39 %), and brain edema requiring osmotherapy (37 %) were the three most common neurological ICU-COMPL. After adjusting for admission variables, duration of ventilation, and ICU length-of-stay, patients with brain edema (OR 5.8; 95 % CI 2, 16.7) had a significantly increased odds for dying during hospitalization whereas patients with hospital-acquired urinary tract infection (UTI) had a decreased odds (OR 0.05; 95 % CI 0.005, 0.6). Sensitivity analysis revealed that UTI occurred later, suggesting a non-causal association with survival. Brain herniation (OR 15.7; 95 % CI 2.6, 95.4) was associated with an unfavorable functional status (GOS 1–3).

Conclusion

ICU-COMPL are very common after msTBI, have a considerable impact on short-term outcomes, and should be considered in the prognostication of these high risk patients. Survival associations of time-dependent complications warrant cautious interpretation.     

Assessing the validity of corneal power estimation using conventional keratometry for intraocular lens power calculation in eyes with Fuch’s dystrophy undergoing Descemet membrane endothelial keratoplasty

Graefe's Archive for Clinical and Experimental Ophthalmology - The present retrospective study was designed to test the hypothesis that the postoperative posterior to preoperative anterior...     

Development and Psychometric Properties of a Computer-Based Standardized Emotional Competence Inventory (MeKKi) for Preschoolers and School-Aged Children

Child Psychiatry & Human Development - A computer-based emotional competence inventory for preschoolers and school-aged children (MeKKi) was developed to assess five components of emotional...