Structure and function of the human Poly(ADP-ribose) polymerase enzyme family

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2013.Cataloged from PDF version of thesis.Includes bibliographical references.The poly(ADP-ribose) polymerase (PARP) family of enzymes in humans is comprised of 17 proteins. PARP-1, the first member of the family, synthesizes a large, complex post-translational modification, poly(ADP-ribose). While PARP-1 and some other PARPs have been extensively functionally characterized, the enzymatic and cellular functions of many PARPs are unknown. This thesis presents work that seeks to characterize the enzymatic functions of the PARP family. First, experimental demonstration of the automodification capacity of each PARP is presented. We find that PARP enzymatic activity largely conforms to bioinformatic predictions of PARP activity. Then, we seek to provide a structural rationale for these enzymatic capabilities based on the analysis of extant and modeled crystal structures of each PARP. We present a structural hypothesis for catalytic differences among PARPs. Finally, we examine methods for the identification of cellular targets of PARP activity and functional interaction partners of PARPs. Together, these elements of PARP characterization will aid in the discovery of physiologically relevant targets and a mechanistic understanding of PARP enzymatic activity in the cellular context.by Jennifer E. Rood.Ph.D

Fracking Up the Future: Recommendations for Hydraulic Fracturing in Gonzales County, TX

Despite its economic appeal, hydraulic fracturing (fracking) has sparked bitter controversy. Allegations of toxic fracking fluids and fracking-induced droughts have made fracking a major public health and environmental concern in the United States. Fracking is dependent on local conditions to a large degree; therefore, we focus on Gonzales County, located within Texas’ Eagle Ford shale region, in order to address county-specific concerns. However, our findings can be applied to help create sustainable practices for fracking in any context. Unfortunately, regulations are limited due to the 2005 Energy Policy Act that prevents federal agencies, including the EPA, from regulating fracking. In order to minimize the external costs of fracking, our research indicates that effective regulations need to be enacted to protect people and the environment from major fracking concerns including overdrawn water sources, wastewater contamination, and chemical releases. We propose that implementing effective regulation will make fracking safer and more profitable for all stakeholders in the long run. Using the catastrophic Deepwater Horizon oil spill in the Gulf of Mexico, we provide a comparison model that is analogous to the current Railroad Commission of Texas’ regulations on fracking. Furthermore, we outline a case study on post-fracking water to demonstrate how a thorough analysis of current practices can create robust recommendations for safer and sustainable fracking practices in the Eagle Ford shale. Finally, our recommendations for fracking in Gonzales County provide possible solutions to many of the concerns associated with fracking

The Importance of Shared Language in Rural Behavioral Health Interventions: An Exploratory Linguistic Analysis

A focus on the use of shared language to enhance congruence in interventionist-client dialogue is missing from traditional research on evidence-based practices and rural behavioral health. This study incorporates qualitative interactional sociolinguistics, which includes discourse analysis (typically written or audio recordings of face-to-face encounters with 11 clients and a study interventionist), to describe those speech patterns in a broad sense (dialect), as well as more specific use of communicative strategies to increase parity in the interaction between a rural interventionist delivering an evidence-based practice in the context of a research study with rural women opioid users in a non-therapeutic context. Study findings indicated that in the context of delivering the intervention, use of a shared language, language pattern congruence, and communication styles can greatly augment the intent of the approach with vulnerable populations. In addition, other communicative strategies connected with traditional Appalachian values – such as religion, home, and family – were also important. This study makes an important contribution to behavioral health research and practice by understanding critical factors that may influence evidence-based practice delivery, particularly in real-world settings with vulnerable populations. These findings have important implications for the utilization of creative approaches to understand critical components of the clinical interaction as indicators of fidelity

Effect of Dietary Composition of Weight Loss Diets on High Sensitivity C-Reactive Protein: The Randomized POUNDS LOST Trial

Overweight and obesity are associated with increased high sensitivity C-reactive protein (hsCRP) levels. The purpose of this study was to determine if weight loss diets differing in fat, protein, or carbohydrate composition differentially reduce hsCRP. POUNDS (Preventing Overweight Using Novel Dietary Strategies) LOST was a two-year trial of overweight and obese adults randomly allocated to one of four weight loss diets with targeted percentages of energy derived from fat, protein, and carbohydrates (20,15,65%;20,25,55%;40,15,45%;40,25,35%, respectively). hsCRP was measured at baseline, 6, and 24 months among 710 participants, and adiposity as measured by dual X-ray absorptiometry (N=340) or abdominal computed tomography (N=126) was correlated with hsCRP change. At 6 months, hsCRP was reduced in all trial participants by −24.7% (IQR +7%,−50%), weight by −6.7% (IQR −3%,−11%), and waist circumference by −6.0% (IQR −3%,−10%) (all P<.002), with no significant differences according to dietary composition. The percent change in hsCRP at 6 and 24 months correlated modestly with change in weight, waist circumference, fasting insulin, fasting glucose, HOMA, and most lipid levels. Reductions in hsCRP persisted despite an approximate 50% regain of weight by 24 months. The percent change in hsCRP at 24 months significantly correlated with changes in total body fat (r=0.42), total abdominal adiposity (r=0.52), subcutaneous abdominal adiposity (r=0.52), visceral adiposity (r=0.47), and hepatic tissue density (r=−0.34) (all P<0.0006). In conclusion, weight loss decreased hsCRP by similar magnitude, irrespective of dietary composition. Clinicians concerned about inflammation and cardiovascular risk should recommend weight loss diets most likely to succeed for their patients

High protein diet maintains glucose production during exercise-induced energy deficit: a controlled trial

<p>Abstract</p> <p>Background</p> <p>Inadequate energy intake induces changes in endogenous glucose production (GP) to preserve muscle mass. Whether addition provision of dietary protein modulates GP response to energy deficit is unclear. The objective was to determine whether exercise-induced energy deficit effects on glucose metabolism are mitigated by increased dietary protein.</p> <p>Methods</p> <p>Nineteen men ([mean ± SD] 23 ± 2 y, VO_2peak59 ± 5 ml·kg^-1·min^-1) were divided into three groups, two consuming moderate (MP; 0.9 g protein kg^-1d^-1), and one high (HP; 1.8 g protein kg^-1d^-1) protein diets (55% energy from carbohydrate) for 11 days. Following 4 days of energy balance (D1-4), energy expenditure was increased for 7 days (D5-12) in all groups. Energy intake was unchanged in two, creating a 1000 kcal d^-1deficit (DEF-MP, DEF-HP; n = 6, both groups), whereas energy balance was maintained in the third (BAL-MP, n = 7). Biochemical markers of substrate metabolism were measured during fasting rest on D4 and D12, as were GP and contribution of gluconeogenesis to endogenous glucose production (<it>f</it>_gng) using 4-h primed, continuous infusions of [6,6-²H₂]glucose (dilution-method) and [2-¹³C]glycerol (MIDA technique). Glycogen breakdown (GB) was derived from GP and <it>f</it>_gng.</p> <p>Results</p> <p>Plasma β-hydroxybutyrate levels increased, and plasma glucose and insulin declined from D4 to D12, regardless of group. DEF-MP experienced decreased plasma GP from D4 to D12 ([mean change ± SD] 0.24 ± 0.24 mg·kg^-1·min^-1), due to reduced GB from D4 (1.40 ± 0.28 mg·kg^-1·min^-1) to D12 (1.16 ± 0.17 mg·kg^-1·min^-1), P < 0.05. Conversely, BAL-MP and DEF-HP sustained GP from D4 to D12 ([mean change ± SD] 0.1 ± 0.5 and 0.0 ± 0.2 mg·kg^-1·min^-1, respectively) by maintaining GB.</p> <p>Conclusion</p> <p>Exercise-induced energy deficit decreased GP and additional dietary protein mitigated that effect.</p

Vitamin D status in female military personnel during combat training

Vitamin D is an essential nutrient for maintaining bone health. Recent data suggest that vitamin D and calcium supplementation might affect stress fracture incidence in military personnel. Although stress fracture is a health risk for military personnel during training, no study has investigated changes in vitamin D status in Soldiers during United States (US) Army basic combat training (BCT). This longitudinal study aimed to determine the effects of BCT on 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) levels in female Soldiers. Serum 25(OH)D and PTH were assessed in 74 fasted Soldier volunteers before and after an 8-week BCT course conducted between August and October in Columbia, South Carolina. In the total study population, 25(OH)D levels decreased (mean ± SD) from 72.9 ± 30.0 to 63.3 ± 19.8 nmol/L (P < 0.05) and PTH levels increased from 36.2 ± 15.8 to 47.5 ± 21.2 pg/mL (P < 0.05) during BCT. Ethnicity affected changes in vitamin D status (ethnicity-by-time interaction, P < 0.05); 25(OH)D decreased (P < 0.05) in both Hispanic and non-Hispanic whites, but did not change in non-Hispanic blacks. Ethnicity did not affect BCT-induced changes in PTH. These data indicate that vitamin D status in female Soldiers may decline during military training in the late summer and early autumn months in the Southeastern US. Future studies should strive to determine the impact of military clothing and seasonality on vitamin D status, as well as the functional impact of declining vitamin D status on bone health

Cadmium Exposure and Pancreatic Cancer in South Louisiana

Cadmium has been hypothesized to be a pancreatic carcinogen. We test the hypothesis that cadmium exposure is a risk factor for pancreatic cancer with a population-based case-control study sampled from a population with persistently high rates of pancreatic cancer (south Louisiana). We tested potential dietary and nondietary sources of cadmium for their association with urinary cadmium concentrations which reflect long-term exposure to cadmium due to the accumulation of cadmium in the kidney cortex. Increasing urinary cadmium concentrations were significantly associated with an increasing risk of pancreatic cancer (2nd quartile OR = 3.34, 3rd = 5.58, 4th = 7.70; test for trend P ≤ 0.0001). Potential sources of cadmium exposure, as documented in the scientific literature, found to be statistically significantly associated with increased risk of pancreatic cancer included working as a plumber, pipefitter or welder (OR = 5.88) and high consumption levels of red meat (4th quartile OR = 6.18) and grains (4th quartile OR = 3.38). Current cigarette smoking, at least 80 pack years of smoking, occupational exposure to cadmium and paints, working in a shipyard, and high consumption of grains were found to be statistically significantly associated with increased concentrations of urinary cadmium. This study provides epidemiologic evidence that cadmium is a potential human pancreatic carcinogen

Reduced adipose tissue oxygenation in human obesity evidence for rarefaction, macrophage chemotaxis, and inflammation without an angiogenic response

OBJECTIVE-Based on rodent studies, we examined the hypothesis that increased adipose tissue (AT) mass in obesity without an adequate support of vascularization might lead to hypoxia, macrophage infiltration, and inflammation. RESEARCH DESIGN AND METHODS-Oxygen partial pressure (AT pO 2) and AT temperature in abdominal AT (9 lean and 12 overweight/obese men and women) was measured by direct insertion of a polarographic Clark electrode. Body composition was measured by dual-energy X-ray absorptiometry, and insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp. Abdominal subcutaneous tissue was used for staining, quantitative RT-PCR, and chemokine secretion assay. RESULTS-AT pO 2 was lower in overweight/obese subjects than lean subjects (47 ± 10.6 vs. 55 ± 9.1 mmHg); however, this level of pO 2 did not activate the classic hypoxia targets (pyruvate dehydrogenase kinase and vascular endothelial growth factor [VEGF]). AT pO 2 was negatively correlated with percent body fat (R =-0.50, P \u3c 0.05). Compared with lean subjects, overweight/ obese subjects had 44% lower capillary density and 58% lower VEGF, suggesting AT rarefaction (capillary drop out). This might be due to lower peroxisome proliferator-activated receptor γ1 and higher collagen VI mRNA expression, which correlated with AT pO 2 (P \u3c 0.05). Of clinical importance, AT pO 2 negatively correlated with CD68 mRNA and macrophage inflammatory protein 1α secretion (R =-0.58, R =-0.79, P \u3c 0.05), suggesting that lower AT pO 2 could drive AT inflammation in obesity. CONCLUSIONS-Adipose tissue rarefaction might lie upstream of both low AT pO 2 and inflammation in obesity. These results suggest novel approaches to treat the dysfunctional AT found in obesity. © 2009 by the American Diabetes Association

The International Atomic Energy Agency International Doubly Labelled Water Database : Aims, Scope and Procedures

Funding Sources The database is generously supported by the IAEA and by the companies Taiyo Nippon Sanso, SERCON and ISOTEC. We are grateful to these companies for their support and especially to Takashi Oono for his tremendous efforts at fund raising on our be half. The authors also gratefully acknowledge funding from the US National Science Foundation (BCS-1824466) awarded to Herman Pontzer. The funders played no role in the content of this manuscript. Open access provided with a grant from the International Atomic Energy Agency. Author Contributions All authors contributed to the drafting and editing of the manuscript and to construction of the IAEA DLW database.Peer reviewedPublisher PD

An ethanolic extract of artemisia scoparia inhibits lipolysis in vivo and has antilipolytic effects on murine adipocytes in vitro

© 2018, American Physiological Society. All rights reserved. An ethanolic extract of Artemisia scoparia (SCO) has metabolically favorable effects on adipocyte development and function in vitro and in vivo. In diet-induced obese mice, SCO supplementation significantly reduced fasting glucose and insulin levels. Given the importance of adipocyte lipolysis in metabolic health, we hypothesized that SCO modulates lipolysis in vitro and in vivo. Free fatty acids and glycerol were measured in the sera of mice fed a high-fat diet with or without SCO supplementation. In cultured 3T3-L1 adipocytes, the effects of SCO on lipolysis were assessed by measuring glycerol and free fatty acid release. Microarray analysis, qPCR, and immunoblotting were used to assess gene expression and protein abundance. We found that SCO supplementation of a high-fat diet in mice substantially reduces circulating glycerol and free fatty acid levels, and we observed a cell-autonomous effect of SCO to significantly attenuate tumor necrosis factor-α (TNFα)-induced lipolysis in cultured adipocytes. Although several prolipolytic and antilipolytic genes were identified by microarray analysis of subcutaneous and visceral adipose tissue from SCO-fed mice, regulation of these genes did not consistently correlate with SCO’s ability to reduce lipolytic metabolites in sera or cell culture media. However, in the presence of TNFα in cultured adipocytes, SCO induced antilipolytic changes in phosphorylation of hormone-sensitive lipase and perilipin. Together, these data suggest that the antilipolytic effects of SCO on adipose tissue play a role in the ability of this botanical extract to improve whole body metabolic parameters and support its use as a dietary supplement to promote metabolic resiliency