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"Stewart, Rachel M"
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The LINC complex transmits integrin-dependent tension to the nuclear lamina and represses epidermal differentiation
2021
While the mechanisms by which chemical signals control cell fate have been well studied, the impact of mechanical inputs on cell fate decisions is not well understood. Here, using the well-defined system of keratinocyte differentiation in the skin, we examine whether and how direct force transmission to the nucleus regulates epidermal cell fate. Using a molecular biosensor, we find that tension on the nucleus through linker of nucleoskeleton and cytoskeleton (LINC) complexes requires integrin engagement in undifferentiated epidermal stem cells and is released during differentiation concomitant with decreased tension on A-type lamins. LINC complex ablation in mice reveals that LINC complexes are required to repress epidermal differentiation in vivo and in vitro and influence accessibility of epidermal differentiation genes, suggesting that force transduction from engaged integrins to the nucleus plays a role in maintaining keratinocyte progenitors. This work reveals a direct mechanotransduction pathway capable of relaying adhesion-specific signals to regulate cell fate.
Journal Article
Three-Tier Models of Reading and Behavior
by
Benner, Gregory J.
,
Marchand-Martella, Nancy E.
,
Martella, Ronald C.
in
Academic Achievement
,
Academic Failure
,
Antisocial Behavior
2007
The purpose of this study was to analyze the research literature on three-tier models of reading and behavior and to provide a descriptive analysis and meta-analytic review of these models. An in-depth review of 17 articles was conducted on the similarities and differences between and among three-tier models of reading (n = 5), models of behavior (n = 7), and integrated models (combining reading and behavior; n = 5). Descriptive analyses were conducted across three areas: student populations, intervention level, and setting. Finally, a meta-analytic review was completed of 11 of the 17 investigations. Scientific evidence shows that one or more levels of these three-tier models leads to improved reading or behavior performance; however, there is a paucity of research detailing the integration of three-tier reading and behavior models. Limitations and directions for future research are discussed.
Journal Article
Ablation of SUN2-containing LINC complexes drives cardiac hypertrophy without interstitial fibrosis
by
King, Megan C
,
Rodriguez, Elisa C
,
Stewart, Rachel M
in
AKT protein
,
Cardiomyocytes
,
Cell Biology
2019
The cardiomyocyte cytoskeleton, including the sarcomeric contractile apparatus, forms a cohesive network with cellular adhesions at the plasma membrane and nuclear-cytoskeletal linkages (LINC complexes) at the nuclear envelope. Human cardiomyopathies are genetically linked to the LINC complex and A-type lamins, but an full understanding of disease etiology in these patients is lacking. Here we show SUN2-null mice display cardiac hypertrophy coincident with enhanced AKT/MAPK signaling, as has been described previously for mice lacking A-type lamins. Surprisingly, in contrast to lamin A/C-null mice, SUN2-null mice fail to show coincident fibrosis or upregulation of pathological hypertrophy markers. Thus, cardiac hypertrophy is uncoupled from pro-fibrotic signaling in this mouse model, which we tie to a requirement for the LINC complex in productive TGFβ signaling. In the absence of SUN2, we detect elevated levels of the integral inner nuclear membrane protein MAN1, an established negative regulator of TGFβ signaling, at the nuclear envelope. We suggest that A-type lamins and SUN2 play antagonistic roles in the modulation of pro-fibrotic signaling through opposite effects on MAN1 levels at the nuclear lamina, suggesting a new perspective on disease etiology.
GOP team takes to the road CAMPAIGN '96 Lawmakers and activists fan across California to spread Dole's message
Republicans Bob Dole and Jack Kemp launched their 81-day uphill battle for the White House, telling tumultuous outdoor rallies in two battleground states that they will reach out to every American to gain the office needed to implement a 15 percent tax cut. After a stop in Denver Friday, the newly formed Dole-Kemp team was to be in Springfield, Ill., and Buffalo, N.Y., for campaign appearances Saturday and Sunday. But first, Dole appeared at a morning farewell appearance in San Diego before GOP leadership Friday.
Newspaper Article
Collagen prolyl 4-hydroxylase 1 is essential for HIF-1α stabilization and TNBC chemoresistance
2018
Collagen prolyl 4-hydroxylase (P4H) expression and collagen hydroxylation in cancer cells are necessary for breast cancer progression. Here, we show that P4H alpha 1 subunit (P4HA1) protein expression is induced in triple-negative breast cancer (TNBC) and HER2 positive breast cancer. By modulating alpha ketoglutarate (α-KG) and succinate levels P4HA1 expression reduces proline hydroxylation on hypoxia-inducible factor (HIF) 1α, enhancing its stability in cancer cells. Activation of the P4HA/HIF-1 axis enhances cancer cell stemness, accompanied by decreased oxidative phosphorylation and reactive oxygen species (ROS) levels. Inhibition of P4HA1 sensitizes TNBC to the chemotherapeutic agent docetaxel and doxorubicin in xenografts and patient-derived models. We also show that increased P4HA1 expression correlates with short relapse-free survival in TNBC patients who received chemotherapy. These results suggest that P4HA1 promotes chemoresistance by modulating HIF-1-dependent cancer cell stemness. Targeting collagen P4H is a promising strategy to inhibit tumor progression and sensitize TNBC to chemotherapeutic agents.
Hyperactivation of HIF-1α is crucial in progression of triple-negative breast cancer, but how HIF-1α stability is maintained in a hypoxia-independent manner is unclear. Here, the authors show collagen prolyl-4-hydroylase 1 stabilises HIF-1α and is involved in chemoresistance in TNBC.
Journal Article
Very Low Prevalence of Vaccine Human Papillomavirus Types Among 18- to 35-Year Old Australian Women 9 Years Following Implementation of Vaccination
2018
Prevalence of quadrivalent vaccine-targeted HPV types has declined by 92% among women aged 18–35. Strong herd protection, and the effectiveness of less than 3 doses of the vaccine, have likely contributed to the size of these reductions.
Abstract
Introduction
A quadrivalent human papillomavirus vaccination program targeting females aged 12–13 years commenced in Australia in 2007, with catch-up vaccination of 14–26 year olds through 2009. We evaluated the program’s impact on HPV prevalence among women aged 18–35 in 2015.
Methods
HPV prevalence among women aged 18–24 and 25–35 was compared with prevalence in these age groups in 2005–2007. For women aged 18–24, we also compared prevalence with that in a postvaccine study conducted in 2010–2012.
Results
For the 2015 sample, Vaccination Register-confirmed 3-dose coverage was 53.3% (65.0% and 40.3% aged 18–24 and 25–35, respectively). Prevalence of vaccine HPV types decreased from 22.7% (2005–2007) and 7.3% (2010–2012), to 1.5% (2015) (P trend < .001) among women aged 18–24, and from 11.8% (2005–2007) to 1.1% (2015) (P = .001) among those aged 25–35.
Conclusions
This study, reporting the longest surveillance follow-up to date, shows prevalence of vaccine-targeted HPV types has continued to decline among young women. A substantial fall also occurred in women aged 25–35, despite lower coverage. Strong herd protection and effectiveness of less than 3 vaccine doses likely contributed to these reductions.
Journal Article
Spatiotemporal immune zonation of the human kidney
by
Sebire, Neil
,
Coleman, Nicholas
,
Aho, Tevita
in
Adult
,
Animals
,
Antiinfectives and antibacterials
2019
Tissue-resident immune cells are important for organ homeostasis and defense. The epithelium may contribute to these functions directly or by cross-talk with immune cells. We used single-cell RNA sequencing to resolve the spatiotemporal immune topology of the human kidney. We reveal anatomically defined expression patterns of immune genes within the epithelial compartment, with antimicrobial peptide transcripts evident in pelvic epithelium in the mature, but not fetal, kidney. A network of tissue-resident myeloid and lymphoid immune cells was evident in both fetal and mature kidney, with postnatal acquisition of transcriptional programs that promote infection-defense capabilities. Epithelial-immune cross-talk orchestrated localization of antibacterial macrophages and neutrophils to the regions of the kidney most susceptible to infection. Overall, our study provides a global overview of how the immune landscape of the human kidney is zonated to counter the dominant immunological challenge.
Journal Article
Vitamin D deficiency contributes directly to the acute respiratory distress syndrome (ARDS)
2015
RationaleVitamin D deficiency has been implicated as a pathogenic factor in sepsis and intensive therapy unit mortality but has not been assessed as a risk factor for acute respiratory distress syndrome (ARDS). Causality of these associations has never been demonstrated.ObjectivesTo determine if ARDS is associated with vitamin D deficiency in a clinical setting and to determine if vitamin D deficiency in experimental models of ARDS influences its severity.MethodsHuman, murine and in vitro primary alveolar epithelial cell work were included in this study.FindingsVitamin D deficiency (plasma 25(OH)D levels <50 nmol/L) was ubiquitous in patients with ARDS and present in the vast majority of patients at risk of developing ARDS following oesophagectomy. In a murine model of intratracheal lipopolysaccharide challenge, dietary-induced vitamin D deficiency resulted in exaggerated alveolar inflammation, epithelial damage and hypoxia. In vitro, vitamin D has trophic effects on primary human alveolar epithelial cells affecting >600 genes. In a clinical setting, pharmacological repletion of vitamin D prior to oesophagectomy reduced the observed changes of in vivo measurements of alveolar capillary damage seen in deficient patients.ConclusionsVitamin D deficiency is common in people who develop ARDS. This deficiency of vitamin D appears to contribute to the development of the condition, and approaches to correct vitamin D deficiency in patients at risk of ARDS should be developed.Trial registrationUKCRN ID 11994.
Journal Article
Assessment of Trinidad community stakeholder perspectives on the use of yeast interfering RNA-baited ovitraps for biorational control of Aedes mosquitoes
by
Stewart, Akilah T. M.
,
Hapairai, Limb K.
,
Duman-Scheel, Molly
in
Aedes
,
Aquatic insects
,
Biology and Life Sciences
2021
Dengue, Zika, chikungunya and yellow fever viruses continue to be a major public health burden. Aedes mosquitoes, the primary vectors responsible for transmitting these viral pathogens, continue to flourish due to local challenges in vector control management. Yeast interfering RNA-baited larval lethal ovitraps are being developed as a novel biorational control tool for Aedes mosquitoes. This intervention circumvents increasing issues with insecticide resistance and poses no known threat to non-target organisms. In an effort to create public awareness of this alternative vector control strategy, gain stakeholder feedback regarding product design and acceptance of the new intervention, and build capacity for its potential integration into existing mosquito control programs, this investigation pursued community stakeholder engagement activities, which were undertaken in Trinidad and Tobago. Three forms of assessment, including paper surveys, community forums, and household interviews, were used with the goal of evaluating local community stakeholders’ knowledge of mosquitoes, vector control practices, and perceptions of the new technology. These activities facilitated evaluation of the hypothesis that the ovitraps would be broadly accepted by community stakeholders as a means of biorational control for Aedes mosquitoes. A comparison of the types of stakeholder input communicated through use of the three assessment tools highlighted the utility and merit of using each tool for assessing new global health interventions. Most study participants reported a general willingness to purchase an ovitrap on condition that it would be affordable and safe for human health and the environment. Stakeholders provided valuable input on product design, distribution, and operation. A need for educational campaigns that provide a mechanism for educating stakeholders about vector ecology and management was highlighted. The results of the investigation, which are likely applicable to many other Caribbean nations and other countries with heavy arboviral disease burdens, were supportive of supplementation of existing vector control strategies through the use of the yeast RNAi-based ovitraps.
Journal Article
Multiple processes contribute to methane emission in a riparian cottonwood forest ecosystem
by
Rood, Stewart B.
,
Scherloski, Lauren M.
,
Selinger, L. Brent
in
Aquatic ecosystems
,
Biogeochemistry
,
Boundary layers
2021
• Methane emission from trees may partially or completely offset the methane sink in upland soils, the only process that has been regularly included in methane budgets for forest ecosystems. Our objective was to analyze multiple biogeochemical processes that influence the production, oxidation and transport of methane in a riparian cottonwood ecosystem and its adjacent river.
• We combined chamber flux measurements on tree stems, forest soil and the river surface with eddy covariance measurements of methane net ecosystem exchange. In addition, we tested whether methanogens were present in cottonwood stems, shallow soil layers and alluvial groundwater.
• Average midday peak in net methane emission measured by eddy covariance was c. 12 nmol m−2 s−1. The average uptake of methane by soils (0.87 nmol m−2 s−1) was largely offset by tree stem methane emission (0.75 nmol m−2 s−1). There was evidence of methanogens in tree stems but not in shallow soil.
• Growing season (May–September) cumulative net methane emission (17.4 mmol CH₄ m−2) included methane produced in cottonwood stems and methane input to the nocturnal boundary layer from the forest and the adjacent river. The multiple processes contributing to methane emission illustrated the linked nature of these adjacent terrestrial and aquatic ecosystems.
Journal Article