👤 Simon T Holden

This study was aimed at assessing the diagnostic utility of whole genome sequence analysis in a well-characterised research cohort of individuals referred with a clinical suspicion of Cornelia de Lange syndrome (CdLS) in whom prior genetic testing had not identified a causative variant. Short-read whole genome sequencing was performed on 195 individuals from 105 families, 108 of whom were affected. 100/108 of the affected individuals had prior relevant genetic testing, with no pathogenic variant being identified. The study group comprised 42 trios in which both parental samples were available for testing (42 affected individuals and 126 unaffected parents), 61 singletons (unrelated affected individuals), and two families with more than one affected individual. The results showed that 32 unrelated probands from 105 families (30.5%) had likely causative coding region-disrupting variants. Four loci were identified in > 1 proband: Show less

The NEDD4-like E3 ubiquitin ligase, WWP2, is involved in a range of host processes from cell differentiation to T cell immunity. Ligase activity is tightly regulated, with WWP2 being held in an autoinhibited state. The binding of a PY motif-containing adaptor, an Ndfip, via the WW domains of NEDD4-like E3 ubiquitin ligases leads to their disinhibition. Here, we show that the canonical Ndfip, NDFIP2, requires multiple PY motifs for interaction with and activation of WWP2. In contrast, the single PY-motif containing Ndfips TMEM127 and SUSD6 functions as a co-disinhibitory pair. TMEM127 and the Salmonella protein SteD also function as a co-disinhibitory pair. However, SteD requires a different region of WWP2, the C2 domain, for interaction with WWP2, and this interaction results in disinhibition of WWP2. These findings demonstrate a range of ways that Ndfips can disinhibit WWP2. To our knowledge, these are the first examples of two Ndfips functioning as co-disinhibitory pairs, and of a bacterial effector that disinhibits an E3 ubiquitin ligase. Show less

The Salmonella enterica effector SteD depletes mature MHC class II (mMHCII) molecules from the surface of infected antigen-presenting cells through ubiquitination of the cytoplasmic tail of the mMHCII β chain. This requires the Nedd4 family HECT E3 ubiquitin ligase Wwp2 and a tumor-suppressing transmembrane protein adaptor Tmem127. Here, through a proteomic screen of dendritic cells, we found that SteD targets the plasma membrane protein CD97 for degradation by a similar mechanism. SteD enhanced ubiquitination of CD97 on K555 and mutation of this residue eliminated the effect of SteD on CD97 surface levels. We showed that CD97 localises to and stabilises the immunological synapse between dendritic cells and T cells. Removal of CD97 by SteD inhibited dendritic cell-T cell interactions and reduced T cell activation, independently of its effect on MHCII. Therefore, SteD suppresses T cell immunity by two distinct processes. Show less

The Salmonella enterica effector SteD depletes mature MHC class II (mMHCII) molecules from the surface of infected antigen-presenting cells through ubiquitination of the cytoplasmic tail of the mMHCII β chain. Here, through a genome-wide mutant screen of human antigen-presenting cells, we show that the NEDD4 family HECT E3 ubiquitin ligase WWP2 and a tumor-suppressing transmembrane protein of unknown biochemical function, TMEM127, are required for SteD-dependent ubiquitination of mMHCII. Although evidently not involved in normal regulation of mMHCII, TMEM127 was essential for SteD to suppress both mMHCII antigen presentation in mouse dendritic cells and MHCII-dependent CD4 Show less

Low back pain (LBP) is responsible for more than 2.5 million visits to US emergency departments (EDs) annually. These patients are usually treated with nonsteroidal anti-inflammatory drugs, acetaminophen, opioids, or skeletal muscle relaxants, often in combination. To compare functional outcomes and pain at 1 week and 3 months after an ED visit for acute LBP among patients randomized to a 10-day course of (1) naproxen + placebo; (2) naproxen + cyclobenzaprine; or (3) naproxen + oxycodone/acetaminophen. This randomized, double-blind, 3-group study was conducted at one urban ED in the Bronx, New York City. Patients who presented with nontraumatic, nonradicular LBP of 2 weeks' duration or less were eligible for enrollment upon ED discharge if they had a score greater than 5 on the Roland-Morris Disability Questionnaire (RMDQ). The RMDQ is a 24-item questionnaire commonly used to measure LBP and related functional impairment on which 0 indicates no functional impairment and 24 indicates maximum impairment. Beginning in April 2012, a total of 2588 patients were approached for enrollment. Of the 323 deemed eligible for participation, 107 were randomized to receive placebo and 108 each to cyclobenzaprine and to oxycodone/acetaminophen. Follow-up was completed in December 2014. All participants were given 20 tablets of naproxen, 500 mg, to be taken twice a day. They were randomized to receive either 60 tablets of placebo; cyclobenzaprine, 5 mg; or oxycodone, 5 mg/acetaminophen, 325 mg. Participants were instructed to take 1 or 2 of these tablets every 8 hours, as needed for LBP. They also received a standardized 10-minute LBP educational session prior to discharge. The primary outcome was improvement in RMDQ between ED discharge and 1 week later. Demographic characteristics were comparable among the 3 groups. At baseline, median RMDQ score in the placebo group was 20 (interquartile range [IQR],17-21), in the cyclobenzaprine group 19 (IQR,17-21), and in the oxycodone/acetaminophen group 20 (IQR,17-22). At 1-week follow-up, the mean RMDQ improvement was 9.8 in the placebo group, 10.1 in the cyclobenzaprine group, and 11.1 in the oxycodone/acetaminophen group. Between-group difference in mean RMDQ improvement for cyclobenzaprine vs placebo was 0.3 (98.3% CI, -2.6 to 3.2; P = .77), for oxycodone/acetaminophen vs placebo, 1.3 (98.3% CI, -1.5 to 4.1; P = .28), and for oxycodone/acetaminophen vs cyclobenzaprine, 0.9 (98.3% CI, -2.1 to 3.9; P = .45). Among patients with acute, nontraumatic, nonradicular LBP presenting to the ED, adding cyclobenzaprine or oxycodone/acetaminophen to naproxen alone did not improve functional outcomes or pain at 1-week follow-up. These findings do not support use of these additional medications in this setting. clinicaltrials.gov Identifier: NCT01587274. Show less

We examined the effect of ileal infusions of lipid emulsion on mRNA levels and biosynthesis of apolipoprotein A-IV (apo A-IV) in jejunal Thiry-Vella fistulas in rats. The rats were surgically prepared with jejunal Thiry-Vella fistulas; after recovery they were deprived of food, equipped with ileal infusion cannulas, then given 8 hr ileal infusions of fatty acid/monoglyceride emulsions. Mucosal synthesis and transcript levels of apo A-IV in the Thiry-Vella loop were then measured. Lipid infusion produced a two-fold stimulation in incorporation of 3H-leucine into apo A-IV-specific protein, but had no significant effect on apo A-IV mRNA levels. These results support the hypothesis that a lipid-elicited, distal gut-derived, systemic signal stimulates the production of apo A-IV by a post-transcriptional mechanism. Show less

We examined the role of vagal innervation in lipid-stimulated increases in expression and synthesis of intestinal apolipoprotein A-IV (apoA-IV). In rats with duodenal cannulas and superior mesenteric lymph fistulas given duodenal infusions of lipid emulsion, vagotomy had no effect on either intestinal lipid transport, lymphatic apoA-IV output, or jejunal mucosal apoA-IV synthesis. In rats with jejunal Thiry-Vella fistulas, ileal lipid infusion elicited a twofold stimulation of apoA-IV synthesis without affecting apoA-IV mRNA levels; vagotomy blocked this increase in apoA-IV synthesis. Direct perfusion of jejunal Thiry-Vella fistulas produced 2- to 2.5-fold increases in both apoA-IV synthesis and mRNA levels in the Thiry-Vella segment; these effects were not influenced by vagal denervation. These results suggest two mechanisms whereby lipid stimulates intestinal apoA-IV production: 1) a vagal-dependent stimulation of jejunal apoA-IV synthesis by distal gut lipid that is independent of changes in apoA-IV mRNA levels and 2) a direct stimulatory effect of proximal gut lipid on both synthesis and mRNA levels of jejunal apoA-IV that is independent of vagal innervation. Show less