The effects of PTHrP-mediated ERK activation on non-small cell lung carcinoma

Each year, more people die from lung cancer than any other cancer related death. Parathyroid hormone-related protein (PTHrP) is expressed in two-thirds of human non-small cell lung carcinoma (NSCLC), the most common form of lung cancer. Patients diagnosed with PTHrP expressing NSCLC may have better prognosis. When further studied, PTHrP positive cells increased the levels of ERK1/2 phosphorylation. Because ERK1/2 has implications on cell growth, we postulated that ERK activation in PTHrP positive cells may contribute to PTHrP's growth inhibition. To understand the role of PTHrP mediated ERK activation, an siRNA model was employed to knock down ERK1, ERK2 or ERK1 and ERK2 combined, where decreasing total ERK protein will lower phosphorylated ERK as well. ERK knockdown in ectopic PTHrP expressing cells was then tested for effects in cell proliferation and localization. ERK2 knockdown decreased proliferation in PTHrP positive cells. ERK1 knockdown increased ERK2 levels as well as increased proliferation at 72 hours, thereby suggesting a feedback mechanism between ERK1 and ERK2 in PTHrP positive cells. ERK1/ERK2 combination knockdown decreased proliferation at 72 hours, suggesting that ERK1 opposes ERK2 and inhibits proliferation. Examination of pERK cellular localization in cells ectopically expressing PTHrP demonstrates that pERK1/2 localizes to the nucleus, therefore pERK1 and pERK2 localization does not contribute to the differences in effect between isoforms. These results allude different effects between ERK isoforms where ERK2 increases proliferation and ERK1 inhibits proliferation. Therefore, PTHrP decreases proliferation through a mechanism that overpowers the pro-proliferative actions of ERK2, which may involve ERK1 activatio

How does situational engagement vary between learners, situations, and classrooms? Findings from the use of intensive longitudinal methods and cross-classified, multi-level models

Situational engagement is defined as context-sensitive, multi-dimensional, and dependent on momentary factors, like instructional practices. Yet, this type of engagement is often studied using data collection or analysis techniques that do not for the examination of the variation in situational engagement that is presumed to exist within persons and across contexts. In this study, we sought to determine the extent to which learners’ situational cognitive, behavioral, and affective engagement varies at the situational, individual learner, and classroom levels. To do so, we drew from three data sets suited to understanding the sources of variation in situational engagement; together, these data sets comprised 12,244 reports collected using intensive longitudinal methods from 1,173 youth in 50 science classrooms and outside-of-school STEM programs. Through the use of multivariate, cross-classified mixed-effects models, we found that the greatest source of variation in situational engagement was attributable to individual learners. Situational and classroom-related sources of variation were smaller than for individual sources but were each still substantia. Classroom-level variation was relatively low for all three dimensions of engagement. There were differences across the three dimensions of situational engagement, such that affective situational engagement was associated with greater variation at the situational level relative to the other dimensions, cognitive engagement was associated with more individual learner variability (and less situational variability). We discuss implications for accounting for situational variability in studies of engagement and other dynamic constructs

Using intensive longitudinal methods to quantify the sources of variability for situational engagement in science learning environments

Abstract Background Situational engagement in science is often described as context-sensitive and varying over time due to the impact of situational factors. But this type of engagement is often studied using data that are collected and analyzed in ways that do not readily permit an understanding of the situational nature of engagement. The purpose of this study is to understand—and quantify—the sources of variability for learners’ situational engagement in science, to better set the stage for future work that measures situational factors and accounts for these factors in models. Results We examined how learners' situational cognitive, behavioral, and affective engagement varies at the situational, individual learner, and classroom levels in three science learning environments (classrooms and an out-of-school program). Through the analysis of 12,244 self-reports of engagement collected using intensive longitudinal methods from 1173 youths, we found that the greatest source of variation in situational engagement was attributable to individual learners, with less being attributable to—in order—situational and classroom sources. Cognitive engagement varied relatively more between individuals, and affective engagement varied more between situations. Conclusions Given the observed variability of situational engagement across learners and contexts, it is vital for studies targeting dynamic psychological and social constructs in science learning settings to appropriately account for situational fluctuations when collecting and analyzing data

Estrogen receptor (ER)α-regulated lipocalin 2 expression in adipose tissue links obesity with breast cancer progression.

Obesity is associated with increased breast cancer (BrCA) incidence. Considering that inactivation of estrogen receptor (ER)α promotes obesity and metabolic dysfunction in women and female mice, understanding the mechanisms and tissue-specific sites of ERα action to combat metabolic-related disease, including BrCA, is of clinical importance. To study the role of ERα in adipose tissue we generated fat-specific ERα knock-out (FERKO) mice. Herein we show that ERα deletion increased adipocyte size, fat pad weight, and tissue expression and circulating levels of the secreted glycoprotein, lipocalin 2 (Lcn2), an adipokine previously associated with BrCA development. Chromatin immunoprecipitation and luciferase reporter studies showed that ERα binds the Lcn2 promoter to repress its expression. Because adipocytes constitute an important cell type of the breast microenvironment, we examined the impact of adipocyte ERα deletion on cancer cell behavior. Conditioned medium from ERα-null adipocytes and medium containing pure Lcn2 increased proliferation and migration of a subset of BrCA cells in culture. The proliferative and promigratory effects of ERα-deficient adipocyte-conditioned medium on BrCA cells was reversed by Lcn2 deletion. BrCA cell responsiveness to exogenous Lcn2 was heightened in cell types where endogenous Lcn2 expression was minimal, but components of the Lcn2 signaling pathway were enriched, i.e. SLC22A17 and 3-hydroxybutyrate dehydrogenase (BDH2). In breast tumor biopsies from women diagnosed with BrCA we found that BDH2 expression was positively associated with adiposity and circulating Lcn2 levels. Collectively these data suggest that reduction of ERα expression in adipose tissue promotes adiposity and is linked with the progression and severity of BrCA via increased adipocyte-specific Lcn2 production and enhanced tumor cell Lcn2 sensitivity

Genetic Architecture of Insulin Resistance in the Mouse

Insulin resistance (IR) is a complex trait with multiple genetic and environmental components. Confounded by large differences between the sexes, environment, and disease pathology, the genetic basis of IR has been difficult to dissect. Here we examine IR and related traits in a diverse population of more than 100 unique male and female inbred mouse strains after feeding a diet rich in fat and refined carbohydrates. Our results show dramatic variation in IR among strains of mice and widespread differences between sexes that are dependent on genotype. We uncover more than 15 genome-wide significant loci and validate a gene, Agpat5, associated with IR. We also integrate plasma metabolite levels and global gene expression from liver and adipose tissue to identify metabolite quantitative trait loci (mQTL) and expression QTL (eQTL), respectively. Our results provide a resource for analysis of interactions between diet, sex, and genetic background in IR

Skeletal muscle action of estrogen receptor α is critical for the maintenance of mitochondrial function and metabolic homeostasis in females

Impaired estrogen receptor α(ERα) action promotes obesity and metabolic dysfunction in humans and mice; however, the mechanisms underlying these phenotypes remain unknown. Considering that skeletal muscle is a primary tissue responsible for glucose disposal and oxidative metabolism, we established that reduced ERαexpression in muscle is associated with glucose intolerance and adiposity in women and female mice. To test this relationship, we generated muscle-specific ERαknockout (MERKO) mice. Impaired glucose homeostasis and increased adiposity were paralleled by diminished muscle oxidative metabolism and bioactive lipid accumulation in MERKO mice. Aberrant mitochondrial morphology, overproduction of reactive oxygen species, and impairment in basal and stress-induced mitochondrial fission dynamics, driven by imbalanced protein kinase A–regulator of calcineurin 1–calcineurin signaling through dynamin-related protein 1, tracked with reduced oxidative metabolism in MERKO muscle. Although muscle mitochondrial DNA (mtDNA) abundance was similar between the genotypes, ERαdeficiency diminished mtDNA turnover by a balanced reduction in mtDNA replication and degradation. Our findings indicate the retention of dysfunctional mitochondria in MERKO muscle and implicate ERαin the preservation of mitochondrial health and insulin sensitivity as a defense against metabolic disease in women

Skeletal muscle action of estrogen receptor α is critical for the maintenance of mitochondrial function and metabolic homeostasis in females

Impaired estrogen receptor α(ERα) action promotes obesity and metabolic dysfunction in humans and mice; however, the mechanisms underlying these phenotypes remain unknown. Considering that skeletal muscle is a primary tissue responsible for glucose disposal and oxidative metabolism, we established that reduced ERαexpression in muscle is associated with glucose intolerance and adiposity in women and female mice. To test this relationship, we generated muscle-specific ERαknockout (MERKO) mice. Impaired glucose homeostasis and increased adiposity were paralleled by diminished muscle oxidative metabolism and bioactive lipid accumulation in MERKO mice. Aberrant mitochondrial morphology, overproduction of reactive oxygen species, and impairment in basal and stress-induced mitochondrial fission dynamics, driven by imbalanced protein kinase A–regulator of calcineurin 1–calcineurin signaling through dynamin-related protein 1, tracked with reduced oxidative metabolism in MERKO muscle. Although muscle mitochondrial DNA (mtDNA) abundance was similar between the genotypes, ERαdeficiency diminished mtDNA turnover by a balanced reduction in mtDNA replication and degradation. Our findings indicate the retention of dysfunctional mitochondria in MERKO muscle and implicate ERαin the preservation of mitochondrial health and insulin sensitivity as a defense against metabolic disease in women