Enzymatic engineering of the porcine genome with transposons and recombinases

<p>Abstract</p> <p>Background</p> <p>Swine is an important agricultural commodity and biomedical model. Manipulation of the pig genome provides opportunity to improve production efficiency, enhance disease resistance, and add value to swine products. Genetic engineering can also expand the utility of pigs for modeling human disease, developing clinical treatment methodologies, or donating tissues for xenotransplantation. Realizing the full potential of pig genetic engineering requires translation of the complete repertoire of genetic tools currently employed in smaller model organisms to practical use in pigs.</p> <p>Results</p> <p>Application of transposon and recombinase technologies for manipulation of the swine genome requires characterization of their activity in pig cells. We tested four transposon systems- <it>Sleeping Beauty</it>, <it>Tol2</it>, <it>piggyBac</it>, and <it>Passport </it>in cultured porcine cells. Transposons increased the efficiency of DNA integration up to 28-fold above background and provided for precise delivery of 1 to 15 transgenes per cell. Both Cre and Flp recombinase were functional in pig cells as measured by their ability to remove a positive-negative selection cassette from 16 independent clones and over 20 independent genomic locations. We also demonstrated a Cre-dependent genetic switch capable of eliminating an intervening positive-negative selection cassette and activating GFP expression from episomal and genome-resident transposons.</p> <p>Conclusion</p> <p>We have demonstrated for the first time that transposons and recombinases are capable of mobilizing DNA into and out of the porcine genome in a precise and efficient manner. This study provides the basis for developing transposon and recombinase based tools for genetic engineering of the swine genome.</p

Cell cycle- and DNA repair pathway-specific effects of apoptosis on tumor suppression

The DNA damage response comprises DNA repair, cell-cycle checkpoint control, and DNA damage-induced apoptosis that collectively promote genomic integrity and suppress tumorigenesis. Previously, we have shown that the Chk2 kinase functions independently of the Mre11 complex (Mre11, Rad50, and Nbs1) and ATM in apoptosis and suppresses tumorigenesis resulting from hypomorphic alleles of Mre11 or Nbs1. Based on this work, we have proposed that Chk2 limits the oncogenic potential of replication-associated DNA damage. Here we further address the role of Chk2 and damage-induced apoptosis in suppressing the oncogenic potential of chromosome breaks. We show that loss of Chk2 or a mutation in p53 (R172P), which selectively impairs its function in apoptosis, rescued the lethality of mice lacking Lig4, a ligase required for nonhomologous end-joining (NHEJ) repair of DNA double-strand breaks in G0/G1. In contrast to Lig4(−/−)p53(−/−) mice, Lig4(−/−)Chk2(−/−) and Lig4(−/−)p53(R172P/R172P) mice were not prone to organ-specific, rapid tumorigenesis. Although the severe NHEJ deficiency of Lig4(−/−) was a less potent initiator of tumorigenesis in the p53(R172P/R172P) and Chk2(−/−) backgrounds, where p53 cell-cycle functions are largely intact, even mild defects in the intra-S and G2/M checkpoints caused by mutations in Nbs1 are sufficient to influence malignancy in p53(R172P/R172P) mice. We conclude that the oncogenic potential of double-strand breaks resulting from NHEJ deficiency is highly restricted by nonapoptotic functions of p53, such as the G1/S checkpoint or senescence, suggesting that the particular facets of the DNA damage response required for tumor suppression are dictated by the proliferative status of the tumor-initiating cell

Gender differences in diabetes self-care in adults with type 1 diabetes: Findings from the T1D Exchange clinic registry

Aims To evaluate gender differences in diabetes self-care components including glycemic, blood pressure and lipid control, utilization of diabetes technologies and acute diabetes complications in adults with type 1 diabetes. Methods A total of 9,481 participants >18 years were included in the analysis, 53% were female. Variables of interest included glycemic control measured by HbA1c, systolic/diastolic blood pressures, presence of dyslipidemia, insulin delivery modality, and rates of acute complications. Results Glycemic control was similar in women and men (mean HbA1c in both groups: 8.1% ± 1.6% (64 ± 16 mmol/mol), (p = 0.54). More women used insulin pump therapy (66% vs. 59%, p < 0.001) but use of sensor technology was similar (p < = 0.42). Women had higher rates of diabetic ketoacidosis (DKA) (5% vs. 3%, p < 0.001) and eating disorders (1.7% vs. 0.1%, p < 0.001). Severe hypoglycemia rates were not different between men and women (p = 0.42). Smoking (6% vs 4%, p < 0.001), systolic (125 ± 14.2 vs. 121 ± 14.4, p < 0.001) and diastolic blood pressure (73.3 ± 9.5 vs. 72.2 ± 9.3, p < 0.001) and rate of dyslipidemia (28% vs. 23%, p < 0.001) were higher in men. Conclusion While glycemic control in type 1 diabetes was similar regardless of gender, rates of DKA and eating disorders were higher in women while rates of smoking, hypertension and dyslipidemia were higher in men

Decade-long bacterial community dynamics in cystic fibrosis airways

The structure and dynamics of bacterial communities in the airways of persons with cystic fibrosis (CF) remain largely unknown. We characterized the bacterial communities in 126 sputum samples representing serial collections spanning 8–9 y from six age-matched male CF patients. Sputum DNA was analyzed by bar-coded pyrosequencing of the V3–V5 hypervariable region of the 16S rRNA gene, defining 662 operational taxonomic units (OTUs) from > 633,000 sequences. Bacterial community diversity decreased significantly over time in patients with typically progressive lung disease but remained relatively stable in patients with a mild lung disease phenotype. Antibiotic use, rather than patient age or lung function,was the primary driver of decreasing diversity. Interpatient variability in community structure exceeded intrapatient variability in serial samples. Antibiotic treatment was associated with pronounced shifts in community structure, but communities showed both short- and longterm resilience after antibiotic perturbation. There was a positive correlation between OTU occurrence and relative abundance, with a small number of persistent OTUs accounting for the greatest abundance. Significant changes in community structure, diversity, or total bacterial density at the time of pulmonary exacerbation were not observed. Despite decreasing community diversity in patients with progressive disease, total bacterial density remained relatively stable over time. These findings show the critical relationship between airway bacterial community structure, disease stage, and clinical state at the time of sample collection. These features are the key parameters with which to assess the complex ecology of the CF airway.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91945/1/2012 PNAS Decade-long bacterial community dynamics in cystic fibrosis airways.pd

State of Type 1 Diabetes Management and Outcomes from the T1D Exchange in 2016–2018

Objective: To provide a snapshot of the profile of adults and youth with type 1 diabetes (T1D) in the United States and assessment of longitudinal changes in T1D management and clinical outcomes in the T1D Exchange registry. Research Design and Methods: Data on diabetes management and outcomes from 22,697 registry participants (age 1–93 years) were collected between 2016 and 2018 and compared with data collected in 2010–2012 for 25,529 registry participants. Results: Mean HbA1c in 2016–2018 increased from 65 mmol/mol at the age of 5 years to 78 mmol/mol between ages 15 and 18, with a decrease to 64 mmol/mol by age 28 and 58–63 mmol/mol beyond age 30. The American Diabetes Association (ADA) HbA1c goal of 10-fold in children <12 years old. HbA1c levels were lower in CGM users than nonusers. Severe hypoglycemia was most frequent in participants ≥50 years old and diabetic ketoacidosis was most common in adolescents and young adults. Racial differences were evident in use of pumps and CGM and HbA1c levels. Conclusions: Data from the T1D Exchange registry demonstrate that only a minority of adults and youth with T1D in the United States achieve ADA goals for HbA1c

The SNARE Protein SNAP23 and the SNARE-Interacting Protein Munc18c in Human Skeletal Muscle Are Implicated in Insulin Resistance/Type 2 Diabetes

OBJECTIVE-Our previous studies suggest that the SNARE protein synaptosomal-associated protein of 23 kDa (SNAP23) is involved in the link between increased lipid levels and insulin resistance in cardiomyocytes. The objective was to determine whether SNAP23 may also be involved in the known association between lipid accumulation in skeletal muscle and insulin resistance/type 2 diabetes in humans, as well as to identify a potential regulator of SNAP23. RESEARCH DESIGN AND METHODS-We analyzed skeletal muscle biopsies from patients with type 2 diabetes and healthy, insulin-sensitive control subjects for expression (mRNA and protein) and intracellular localization (subcellular fractionation and immunohistochemistry) of SNAP23, and for expression of proteins known to interact with SNARE proteins. Insulin resistance was determined by a euglycemic hyperinsulinemic clamp Potential mechanisms for regulation of SNAP23 were also investigated in the skeletal muscle cell line L6. RESULTS-We showed increased SNAP23 levels in skeletal muscle from patients with type 2 diabetes compared with that from lean control subjects Moreover, SNAP23 was redistributed from the plasma membrane to the microsomal/cytosolic compartment in the patients with the type 2 diabetes Expression of the SNARE-interacting protein Munc18c was higher in skeletal muscle from patients with type 2 diabetes Studies in L6 cells showed that Munc18c promoted the expression of SNAP23. CONCLUSIONS-We have translated our previous in vitro results into humans by showing that there is a change in the distribution of SNAP23 to the interior of the cell in skeletal muscle from patients with type 2 diabetes. We also showed that Munc18c is a potential regulator of SNAP23. Diabetes 59: 1870-1878, 201

Teaching Matters, Volume 2: Essays by the faculty and staff at the University of Maine at Farmington

Essays by the faculty and staff at the University of Maine at Farmington.https://scholarworks.umf.maine.edu/publications/1087/thumbnail.jp

We are all one together : peer educators\u27 views about falls prevention education for community-dwelling older adults - a qualitative study

Background: Falls are common in older people. Despite strong evidence for effective falls prevention strategies, there appears to be limited translation of these strategies from research to clinical practice. Use of peers in delivering falls prevention education messages has been proposed to improve uptake of falls prevention strategies and facilitate translation to practice. Volunteer peer educators often deliver educational presentations on falls prevention to community-dwelling older adults. However, research evaluating the effectiveness of peer-led education approaches in falls prevention has been limited and no known study has evaluated such a program from the perspective of peer educators involved in delivering the message. The purpose of this study was to explore peer educators’ perspective about their role in delivering peer-led falls prevention education for community-dwelling older adults. Methods: A two-stage qualitative inductive constant comparative design was used.In stage one (core component) focus group interviews involving a total of eleven participants were conducted. During stage two (supplementary component) semi-structured interviews with two participants were conducted. Data were analysed thematically by two researchers independently. Key themes were identified and findings were displayed in a conceptual framework. Results: Peer educators were motivated to deliver educational presentations and importantly, to reach an optimal peer connection with their audience. Key themes identified included both personal and organisational factors that impact on educators’ capacity to facilitate their peers’ engagement with the message. Personal factors that facilitated message delivery and engagement included peer-to-peer connection and perceived credibility, while barriers included a reluctance to accept the message that they were at risk of falling by some members in the audience. Organisational factors, including ongoing training for peer educators and formative feedback following presentations, were perceived as essential because they affect successful message delivery. Conclusions: Peer educators have the potential to effectively deliver falls prevention education to older adults and influence acceptance of the message as they possess the peer-to-peer connection that facilitates optimal engagement. There is a need to consider incorporating learnings from this research into a formal large scale evaluation of the effectiveness of the peer education approach in reducing falls in older adults

Design and feasibility testing of a novel group intervention for young women who binge drink in groups

BackgroundYoung women frequently drink alcohol in groups and binge drinking within these natural drinking groups is common. This study describes the design of a theoretically and empirically based group intervention to reduce binge drinking among young women. It also evaluates their engagement with the intervention and the acceptability of the study methods.MethodsFriendship groups of women aged 18–35 years, who had two or more episodes of binge drinking (>6 UK units on one occasion; 48g of alcohol) in the previous 30 days, were recruited from the community. A face-to-face group intervention, based on the Health Action Process Approach, was delivered over three sessions. Components of the intervention were woven around fun activities, such as making alcohol free cocktails. Women were followed up four months after the intervention was delivered. Results The target of 24 groups (comprising 97 women) was recruited. The common pattern of drinking was infrequent, heavy drinking (mean consumption on the heaviest drinking day was UK 18.1 units). Process evaluation revealed that the intervention was delivered with high fidelity and acceptability of the study methods was high. The women engaged positively with intervention components and made group decisions about cutting down. Twenty two groups set goals to reduce their drinking, and these were translated into action plans. Retention of individuals at follow up was 87%.ConclusionsThis study successfully recruited groups of young women whose patterns of drinking place them at high risk of acute harm. This novel approach to delivering an alcohol intervention has potential to reduce binge drinking among young women. The high levels of engagement with key steps in the behavior change process suggests that the group intervention should be tested in a full randomised controlled trial

What's normal? Oligosaccharide concentrations and profiles in milk produced by healthy women vary geographically.

Background: Human milk is a complex fluid comprised of myriad substances, with one of the most abundant substances being a group of complex carbohydrates referred to as human milk oligosaccharides (HMOs). There has been some evidence that HMO profiles differ in populations, but few studies have rigorously explored this variability.Objectives: We tested the hypothesis that HMO profiles differ in diverse populations of healthy women. Next, we examined relations between HMO and maternal anthropometric and reproductive indexes and indirectly examined whether differences were likely related to genetic or environmental variations.Design: In this cross-sectional, observational study, milk was collected from a total of 410 healthy, breastfeeding women in 11 international cohorts and analyzed for HMOs by using high-performance liquid chromatography.Results: There was an effect of the cohort (P 4 times higher in milk collected in Sweden than in milk collected in rural Gambia (mean ± SEM: 473 ± 55 compared with 103 ± 16 nmol/mL, respectively; P < 0.05), and disialyllacto-N-tetraose (DSLNT) concentrations ranged from 216 ± 14 nmol/mL (in Sweden) to 870 ± 68 nmol/mL (in rural Gambia) (P < 0.05). Maternal age, time postpartum, weight, and body mass index were all correlated with several HMOs, and multiple differences in HMOs [e.g., lacto-N-neotetrose and DSLNT] were shown between ethnically similar (and likely genetically similar) populations who were living in different locations, which suggests that the environment may play a role in regulating the synthesis of HMOs.Conclusions: The results of this study support our hypothesis that normal HMO concentrations and profiles vary geographically, even in healthy women. Targeted genomic analyses are required to determine whether these differences are due at least in part to genetic variation. A careful examination of sociocultural, behavioral, and environmental factors is needed to determine their roles in this regard. This study was registered at clinicaltrials.gov as NCT02670278