👤 Dale S Bond

This study used compositional data techniques that address the interdependence of 24-h movement behaviors (sleep, sedentary behavior [SB], light-intensity physical activity [LPA], moderate-to-vigorous intensity physical activity [MVPA]) to examine: (1) how patients undergoing metabolic bariatric surgery (MBS) allocate time among these behaviors before MBS, and (2) whether overall time-use composition and modeled reallocation patterns relate to early weight loss after MBS. Participants wore an accelerometer 24 h/day for 10 days before MBS to measure time in sleep, SB, LPA, and MVPA. Isotemporal substitution models estimated differences in 6-month post-MBS percentage total weight loss (%TWL) associated with reallocations of these pre-surgery movement behaviors. Forty-five participants provided valid data. Pre-MBS time-use composition was associated with %TWL (23.8 ± 5.1%; F = 2.66, p = 0.047). Reallocating 15-60 SB or LPA minutes/day to MVPA was estimated to relate to 0.9-3.5% greater %TWL. Reallocating 15-30 MVPA minutes/day to SB or LPA was estimated to relate to 1.4-5.0% less %TWL (all comparisons p < 0.05). Other reallocations were non-significant. In conclusion, modeled shifts in time from SB or LPA to MVPA and vice versa were associated with estimated increases or decreases in early post-surgical weight loss, respectively. Experimental research is needed to clarify causal relationships and inform interventions to improve MBS outcomes. Show less

T-cell acute lymphoblastic leukemias (T-ALL) represent 15% of pediatric and 25% of adult ALL. Since they have a particularly poor outcome in relapsed/refractory cases, identifying prognosis factors at diagnosis is crucial to adapting treatment for high-risk patients. Unlike acute myeloid leukemia and BCP ALL, chromosomal rearrangements leading to chimeric fusion-proteins with strong prognosis impact are sparsely reported in T-ALL. To address this issue an RT-MPLA assay was applied to a consecutive series of 522 adult and pediatric T-ALLs and identified a fusion transcript in 20% of cases. PICALM-MLLT10 (4%, n = 23), NUP214-ABL1 (3%, n = 19) and SET-NUP214 (3%, n = 18) were the most frequent. The clinico-biological characteristics linked to fusion transcripts in a subset of 235 patients (138 adults in the GRAALL2003/05 trials and 97 children from the FRALLE2000 trial) were analyzed to identify their prognosis impact. Patients with HOXA trans-deregulated T-ALLs with MLLT10, KMT2A and SET fusion transcripts (17%, 39/235) had a worse prognosis with a 5-year EFS of 35.7% vs 63.7% (HR = 1.63; p = 0.04) and a trend for a higher cumulative incidence of relapse (5-year CIR = 45.7% vs 25.2%, HR = 1.6; p = 0.11). Fusion transcripts status in T-ALL can be robustly identified by RT-MLPA, facilitating risk adapted treatment strategies for high-risk patients. Show less

Yeasts provide an excellent genetically tractable eukaryotic system for investigating the function of genes in their biological context, and are especially relevant for those conserved genes that cause disease. We study the role of Show less

Owing to the loss of heterochromatin integrity that occurs during thyroid tumorigenesis, the expression of Heterochromatin Protein 1 isoforms HP1α and HP1β was assessed by immunohistochemistry in 189 thyroid tumors and non-neoplastic tissues. Expression of HP1β was significantly decreased in all thyroid lesions, except in follicular adenomas, when compared with matched adjacent normal tissue. This loss of HP1β expression may in part be caused by microRNA dysregulation. An example is miR-205, a microRNA that is abundantly upregulated in thyroid carcinomas and shown to reduce the expression of HP1β. In contrast to HP1β, HP1α expression was only reduced in metastatic carcinomas and poorly differentiated lesions. These results suggest the reduction of HP1β followed by a decrease in HP1α contributes to the pathogenesis of thyroid carcinomas, and their loss is a potential marker of thyroid malignancy and metastatic potential, respectively. Show less

Compartmentalization of cAMP-dependent protein kinase A (PKA) by A-kinase anchoring proteins (AKAPs) targets PKA to distinct subcellular locations in many cell types. However, the question of whether AKAP-mediated PKA anchoring in the heart regulates cardiac contractile function has not been addressed. We disrupted AKAP-mediated PKA anchoring in cardiac myocytes by introducing, via adenovirus-mediated gene transfer, Ht31, a peptide that binds the PKA regulatory subunit type II (RII) with high affinity. This peptide competes with endogenous AKAPs for RII binding. Ht31P (a proline-substituted derivative), which does not bind RII, was used as a negative control. We then investigated the effects of Ht31 expression on RII distribution, Ca(2+) cycling, cell shortening, and PKA-dependent substrate phosphorylation. By confocal microscopy, we showed redistribution of RII from the perinuclear region and from periodic transverse striations in Ht31P-expressing cells to a diffuse cytosolic localization in Ht31-expressing cells. In the presence of 10 nmol/L isoproterenol, Ht31-expressing myocytes displayed an increased rate and amplitude of cell shortening and relaxation compared with control cells (uninfected and Ht31P-expressing myocytes); with isoproterenol stimulation we observed decreased time to 90% decline in Ca(2+) but no significant difference between Ht31-expressing and control cells in the rate of Ca(2+) cycling or amplitude of the Ca(2+) transient. The increase in PKA-dependent phosphorylation of troponin I and myosin binding protein C on isoproterenol stimulation was significantly reduced in Ht31-expressing cells compared with controls. Our results demonstrate that, in response to beta-adrenergic stimulation, cardiomyocyte function and substrate phosphorylation by PKA is regulated by targeting of PKA by AKAPs. Show less

cAMP-dependent protein kinase (PKA) regulates a broad range of cellular responses in the cardiac myocyte. Downstream regulation of the PKA pathway is mediated by a class of scaffolding proteins called A-kinase anchoring proteins (AKAPs), which sequester PKA to specific subcellular locations through binding to its regulatory subunit (R). However, the effect of RII autophosphorylation on AKAP binding and the degree of RII autophosphorylation in failing and nonfailing human hearts remains unknown. We investigated AKAP-RII binding by overlay analysis and surface plasmon resonance spectroscopy and measured RII autophosphorylation in human hearts by backphosphorylation. Binding of Ht31 peptide (representing the RII-binding region of AKAPs) to cardiac RII was increased approximately 145% (P<0.01) for autophosphorylated RII relative to unphosphorylated control. By surface plasmon resonance, RII autophosphorylation significantly increased binding affinity to Ht31 by approximately 200% (P<0.01). Baseline PKA-dependent phosphorylation of RII was significantly decreased approximately 30% (P<0.05) in human hearts with dilated cardiomyopathy compared with nonfailing controls. These results suggest that AKAP binding of PKA in the heart is regulated by RII autophosphorylation. Therefore AKAP targeting of PKA may be reduced in patients with end-stage heart failure. This mechanism may be responsible for the decreased cAMP-dependent phosphorylation of proteins in dilated cardiomyopathy that we and others have previously observed. Show less

Stimulation of beta-adrenergic receptors activates type I and II cyclic AMP-dependent protein kinase A, resulting in phosphorylation of various proteins in the heart. It has been proposed that PKA II compartmentalization by A-kinase-anchoring proteins (AKAPs) regulates cyclic AMP-dependent signaling in the cell. We investigated the expression and localization of AKAP100 in adult hearts. By immunoblotting, we identified AKAP100 in adult rat and human hearts, and showed that type I and II regulatory (RI and II) subunits of PKA are present in the rat heart. By immunofluorescence and confocal microscopy of rat cardiac myocytes and cryostat sections of rat left ventricle papillary muscles, we localized AKAP100 to the nucleus, sarcolemma, intercalated disc, and at the level of the Z-line. After double immunostaining of transverse cross-sections of the papillary muscles with AKAP100 plus alpha-actinin-specific antibodies or AKAP100 plus ryanodine receptor-specific antibodies, confocal images showed AKAP100 localization at the region of the transverse tubule/junctional sarcoplasmic reticulum. RI is distributed differently from RII in the myocytes. RII, but not RI, was colocalized with AKAP100 in the rat heart. Our studies suggest that AKAP100 tethers PKA II to multiple subcellular compartments for phosphorylation of different pools of substrate proteins in the heart. Show less