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Armour S.M.,Harvard University | Armour S.M.,Smilow Center for Translational Research | Bennett E.J.,Harvard University | Bennett E.J.,University of California at San Diego | And 7 more authors.
Molecular and Cellular Biology | Year: 2013

Although many functions and targets have been attributed to the histone and protein deacetylase SIRT1, a comprehensive analysis of SIRT1 binding proteins yielding a high-confidence interaction map has not been established. Using a comparative statistical analysis of binding partners, we have assembled a high-confidence SIRT1 interactome. Employing this method, we identified the deubiquitinating enzyme ubiquitin-specific protease 22 (USP22), a component of the deubiquitinating module (DUBm) of the SAGA transcriptional coactivating complex, as a SIRT1-interacting partner. We found that this interaction is highly specific, requires the ZnF-UBP domain of USP22, and is disrupted by the inactivating H363Y mutation within SIRT1. Moreover, we show that USP22 is acetylated on multiple lysine residues and that alteration of a single lysine (K129) within the ZnF-UBP domain is sufficient to alter interaction of the DUBm with the core SAGA complex. Furthermore, USP22-mediated recruitment of SIRT1 activity promotes the de cetylation of individual SAGA complex components. Our results indicate an important role of SIRT1- mediated deacetylation in regulating the formation of DUBm subcomplexes within the larger SAGA complex. © 2013, American Society for Microbiology.

Tebas P.,University of Pennsylvania | Stein D.,Yeshiva University | Tang W.W.,Sangamo BioSciences | Frank I.,University of Pennsylvania | And 17 more authors.
New England Journal of Medicine | Year: 2014

BACKGROUND: CCR5 is the major coreceptor for human immunodeficiency virus (HIV). We investigated whether site-specific modification of the gene ("gene editing") - in this case, the infusion of autologous CD4 T cells in which the CCR5 gene was rendered permanently dysfunctional by a zinc-finger nuclease (ZFN) - is safe. METHODS: We enrolled 12 patients in an open-label, nonrandomized, uncontrolled study of a single dose of ZFN-modified autologous CD4 T cells. The patients had chronic aviremic HIV infection while they were receiving highly active antiretroviral therapy. Six of them underwent an interruption in antiretroviral treatment 4 weeks after the infusion of 10 billion autologous CD4 T cells, 11 to 28% of which were genetically modified with the ZFN. The primary outcome was safety as assessed by treatment-related adverse events. Secondary outcomes included measures of immune reconstitution and HIV resistance. RESULTS: One serious adverse event was associated with infusion of the ZFN-modified autologous CD4 T cells and was attributed to a transfusion reaction. The median CD4 T-cell count was 1517 per cubic millimeter at week 1, a significant increase from the preinfusion count of 448 per cubic millimeter (P<0.001). The median concentration of CCR5-modified CD4 T cells at 1 week was 250 cells per cubic millimeter. This constituted 8.8% of circulating peripheral-blood mononuclear cells and 13.9% of circulating CD4 T cells. Modified cells had an estimated mean half-life of 48 weeks. During treatment interruption and the resultant viremia, the decline in circulating CCR5-modified cells (-1.81 cells per day) was significantly less than the decline in unmodified cells (-7.25 cells per day) (P = 0.02). HIV RNA became undetectable in one of four patients who could be evaluated. The blood level of HIV DNA decreased in most patients. CONCLUSIONS: CCR5-modified autologous CD4 T-cell infusions are safe within the limits of this study. Copyright © 2014 Massachusetts Medical Society.

Barz C.S.,RWTH Aachen | Bessaih T.,Paris-Sorbonne University | Bessaih T.,French National Center for Scientific Research | Bessaih T.,French Institute of Health and Medical Research | And 5 more authors.
Brain Structure and Function | Year: 2016

Schizophrenic patients show altered sensory perception as well as changes in electrical and magnetic brain responses to sustained, frequency-modulated sensory stimulation. Both the amplitude and temporal precision of the neural responses differ in patients as compared to control subjects, and these changes are most pronounced for stimulation at gamma frequencies (20–40 Hz). In addition, patients display enhanced spontaneous gamma oscillations, which has been interpreted as ‘neural noise’ that may interfere with normal stimulus processing. To investigate electrophysiological markers of aberrant sensory processing in a model of schizophrenia, we recorded neuronal activity in primary somatosensory cortex of mice heterozygous for the schizophrenia susceptibility gene Neuregulin 1. Sensory responses to sustained 20–70 Hz whisker stimulation were analyzed with respect to firing rates, spike precision (phase locking) and gamma oscillations, and compared to baseline conditions. The mutants displayed elevated spontaneous firing rates, a reduced gain in sensory-evoked spiking and gamma activity, and reduced spike precision of 20–40 Hz responses. These findings present the first in vivo evidence of the linkage between a genetic marker and altered stimulus encoding, thus suggesting a novel electrophysiological endophenotype of schizophrenia. © 2014, Springer-Verlag Berlin Heidelberg.

Stine R.R.,Institute for Diabetes | Stine R.R.,Smilow Center for Translational Research | Shapira S.N.,Institute for Diabetes | Shapira S.N.,Smilow Center for Translational Research | And 10 more authors.
Molecular Metabolism | Year: 2016

Objective: The induction of beige/brite adipose cells in white adipose tissue (WAT) is associated with protection against high fat diet-induced obesity and insulin resistance in animals. The helix-loop-helix transcription factor Early B-Cell Factor-2 (EBF2) regulates brown adipose tissue development. Here, we asked if EBF2 regulates beige fat cell biogenesis and protects animals against obesity. Methods: In addition to primary cell culture studies, we used Ebf2 knockout mice and mice overexpressing EBF2 in the adipose tissue to study the necessity and sufficiency of EBF2 to induce beiging in vivo. Results: We found that EBF2 is required for beige adipocyte development in mice. Subcutaneous WAT or primary adipose cell cultures from Ebf2 knockout mice did not induce Uncoupling Protein 1 (UCP1) or a thermogenic program following adrenergic stimulation. Conversely, over-expression of EBF2 in adipocyte cultures induced UCP1 expression and a brown-like/beige fat-selective differentiation program. Transgenic expression of Ebf2 in adipose tissues robustly stimulated beige adipocyte development in the WAT of mice, even while housed at thermoneutrality. EBF2 overexpression was sufficient to increase mitochondrial function in WAT and protect animals against high fat diet-induced weight gain. Conclusions: Taken together, our results demonstrate that EBF2 controls the beiging process and suggest that activation of EBF2 in WAT could be used to reduce obesity. © 2015 The Authors.

Khera A.V.,Massachusetts General Hospital | Qamar A.,Smilow Center for Translational Research | Qamar A.,Cardiovascular Institute | Reilly M.P.,Smilow Center for Translational Research | And 5 more authors.
American Journal of Cardiology | Year: 2015

Recent trials demonstrated substantial improvement in lipid parameters with inhibition of proprotein convertase subtilisin-like/kexin type 9 (PCSK9). Although statins and fibrates have been reported to increase plasma PCSK9 levels, the effect of niacin on PCSK9 is unknown. We investigated the impact of niacin, atorvastatin, and fenofibrate on PCSK9 levels in 3 distinct studies. A statin-only study randomized 74 hypercholesterolemic patients to placebo, atorvastatin 10 mg/day, or atorvastatin 80 mg/day for 16 weeks. A dose-related increase in PCSK9 was noted such that atorvastatin 80 mg increased PCSK9 by a mean +27% (95% confidence interval [CI] +12 to +42), confirming the effect of statin therapy on raising PCSK9. A second study randomized 70 patients with carotid atherosclerosis to simvastatin 20 mg/day, simvastatin 80 mg/day, or simvastatin 20 mg/extended-release (ER) niacin 2 g/day. PCSK9 levels were increased with statin therapy, but decreased with the simvastatin 20 mg/ER niacin combination (mean -13%, CI -3 to -23). A final study involved 19 dyslipidemic participants on atorvastatin 10 mg with serial addition of fenofibric acid 135 mg followed by ER niacin 2 g/day. Fenofibric acid led to a +23% (CI +10 to +36, p = 0.001) increase in PCSK9; the addition of niacin resulted in a subsequent -17% decrease (CI -19 to -5, p = 0.004). A positive association was noted between change in PCSK9 and low-density lipoprotein cholesterol levels (r = 0.62, p = 0.006) with the addition of niacin. In conclusion, niacin therapy offsets the increase in PCSK9 levels noted with statin and fibrate therapy. A portion of the low-density lipoprotein cholesterol reduction seen with niacin therapy may be due to reduction in PCSK9. © 2015 Elsevier Inc.

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