Estrogen Regulates Estrogen Receptors and Antioxidant Gene Expression in Mouse Skeletal Muscle

Background: Estrogens are associated with the loss of skeletal muscle strength in women with age. Ovarian hormone removal by ovariectomy in mice leads to a loss of muscle strength, which is reversed with 17β-estradiol replacement. Aging is also associated with an increase in antioxidant stress, and estrogens can improve antioxidant status via their interaction with estrogen receptors (ER) to regulate antioxidant gene expression. The purpose of this study was to determine if ER and antioxidant gene expression in skeletal muscle are responsive to changes in circulating estradiol, and if ERs regulate antioxidant gene expression in this tissue. Methodology/Principal Findings: Adult C57BL/6 mice underwent ovariectomies or sham surgeries to remove circulating estrogens. These mice were implanted with placebo or 17β-estradiol pellets acutely or chronically. A separate experiment examined mice that received weekly injections of Faslodex to chronically block ERs. Skeletal muscles were analyzed for expression of ER genes and proteins and antioxidant genes. ERα was the most abundant, followed by Gper and ERβ in both soleus and EDL muscles. The loss of estrogens through ovariectomy induced ERα gene and protein expression in the soleus, EDL, and TA muscles at both the acute and chronic time points. Gpx3 mRNA was also induced both acutely and chronically in all 3 muscles in mice receiving 17β-estradiol. When ERs were blocked using Faslodex, Gpx3 mRNA was downregulated in the soleus muscle, but not the EDL and TA muscles. Conclusions/Significance: These data suggest that Gpx3 and ERα gene expression are sensitive to circulating estrogens in skeletal muscle. ERs may regulate Gpx3 gene expression in the soleus muscle, but skeletal muscle regulation of Gpx3 via ERs is dependent upon muscle type. Further work is needed to determine the indirect effects of estrogen and ERα on Gpx3 expression in skeletal muscle, and their importance in the aging process

Aligning systems science and community-based participatory research: A case example of the Community Health Advocacy and Research Alliance (CHARA).

Partnered research may help bridge the gap between research and practice. Community-based participatory research (CBPR) supports collaboration between scientific researchers and community members that is designed to improve capacity, enhance trust, and address health disparities. Systems science aims to understand the complex ways human-ecological coupled systems interact and apply knowledge to management practices. Although CBPR and systems science display complementary principles, only a few articles describe synergies between these 2 approaches. In this article, we explore opportunities to utilize concepts from systems science to understand the development, evolution, and sustainability of 1 CBPR partnership: The Community Health Advocacy and Research Alliance (CHARA). Systems science tools may help CHARA and other CBPR partnerships sustain their core identities while co-evolving in conjunction with individual members, community priorities, and a changing healthcare landscape. Our goal is to highlight CHARA as a case for applying the complementary approaches of CBPR and systems science to (1) improve academic/community partnership functioning and sustainability, (2) ensure that research addresses the priorities and needs of end users, and (3) support more timely application of scientific discoveries into routine practice

Transgenic overexpression of γ-cytoplasmic actin protects against eccentric contraction-induced force loss in mdx mice

<p>Abstract</p> <p>Background</p> <p>γ-cytoplasmic (γ-_cyto) actin levels are elevated in dystrophin-deficient <it>mdx </it>mouse skeletal muscle. The purpose of this study was to determine whether further elevation of γ-_cytoactin levels improve or exacerbate the dystrophic phenotype of <it>mdx </it>mice.</p> <p>Methods</p> <p>We transgenically overexpressed γ-_cytoactin, specifically in skeletal muscle of mdx mice (<it>mdx</it>-TG), and compared skeletal muscle pathology and force-generating capacity between <it>mdx </it>and <it>mdx</it>-TG mice at different ages. We investigated the mechanism by which γ-_cytoactin provides protection from force loss by studying the role of calcium channels and stretch-activated channels in isolated skeletal muscles and muscle fibers. Analysis of variance or independent <it>t</it>-tests were used to detect statistical differences between groups.</p> <p>Results</p> <p>Levels of γ-_cytoactin in <it>mdx</it>-TG skeletal muscle were elevated 200-fold compared to <it>mdx </it>skeletal muscle and incorporated into thin filaments. Overexpression of γ-_cytoactin had little effect on most parameters of <it>mdx </it>muscle pathology. However, γ-_cytoactin provided statistically significant protection against force loss during eccentric contractions. Store-operated calcium entry across the sarcolemma did not differ between <it>mdx </it>fibers compared to wild-type fibers. Additionally, the omission of extracellular calcium or the addition of streptomycin to block stretch-activated channels did not improve the force-generating capacity of isolated extensor digitorum longus muscles from <it>mdx </it>mice during eccentric contractions.</p> <p>Conclusions</p> <p>The data presented in this study indicate that upregulation of γ-_cytoactin in dystrophic skeletal muscle can attenuate force loss during eccentric contractions and that the mechanism is independent of activation of stretch-activated channels and the accumulation of extracellular calcium.</p

Attitudes and Beliefs Regarding Pain in Interprofessional Education: A Multifaceted Dilemma

Purpose: To evaluate entry-level physical and occupational therapy student attitudes and beliefs toward treating a person with pain, at various levels of their didactic learning. Description: Across health professions, pain education varies considerably with its curricula of pain definitions, management principles, and interprofessional collaboration. The result of this discord has led to a broad range of behaviors and attitudes among health professions and their students, which can ultimately affect a person’s participation in society. Literature supports the importance of a curriculum that addresses students’ attitudes and beliefs toward treating people in pain in an attempt to preclude the formation of negative attitudes during clinical practice. Summary of Use: A modified open-ended sentence stem format was used to gather the qualitative data of 241 graduate students enrolled in occupational and physical therapy entry-level programs to assess their knowledge and attitudes toward pain. Students completed a questionnaire including two open-ended sentence stems. Verbatim transcripts of the students’ responses were thematically analyzed by five-blinded faculty, who constructed nine themes that reflected students’ responses. Interrater reliability was strong with an average of 89.4% agreement rating (range 68.1-97.6%). Analysis of the responses to the first stem, “People in pain are…” yielded four themes: 1) negative mood sate (suffering/unhappy); 2) negative trait or characteristic (wimpy/uncooperative); 3) needy; and 4) having real problems. The percentages of the students’ attitudes reflected in each theme were 28.8%, 5.1%, 42.7%, 23.4% respectively. Responses were dominated by themes related to a negative mood state and being needy. Negative attitudes toward treatment of persons in pain have been shown to contribute to disparities in pain care. Analysis of responses to the second stem question, “Working with patients in pain will be …” yielded five themes: 1) intellectually stimulating; 2) worthwhile/rewarding; 3) unpleasant/difficult; 4) challenging/complex; and 5) routine in practice. The frequency of responses were 8.3%, 33%, 19.8%, 38.9%, and 12.6% respectively and were dominated by themes suggesting that working with people in pain will be challenging yet rewarding. Importance to Member: Despite the frequency of pain problems in society, pain and the treatment of people in pain have not been major components of healthcare education. The International Association for the Study of Pain (IASP) provides a guideline for knowledge of pain management for entry-level physical and occupational therapists. Knowing what preconceived attitudes and beliefs students have in treating persons with pain can help drive the development of a pain curriculum that is both academically inclusive and behaviorally influential. As educators, we have the opportunity to address this multifaceted dilemma to meet the IASP guidelines and bridge the gap between interprofessional pain education and the optimal treatment of those in pain

Dominant lethal pathologies in male mice engineered to contain an X-linked DUX4 transgene

Facioscapulohumeral muscular dystrophy (FSHD) is an enigmatic disease associated with epigenetic alterations in the subtelomeric heterochromatin of the D4Z4 macrosatellite repeat. Each repeat unit encodes DUX4, a gene that is normally silent in most tissues. Besides muscular loss, most patients suffer retinal vascular telangiectasias. To generate an animal model, we introduced a doxycycline-inducible transgene encoding DUX4 and 3' genomic DNA into a euchromatic region of the mouse X chromosome. Without induction, DUX4 RNA was expressed at low levels in many tissues and animals displayed a variety of unexpected dominant leaky phenotypes, including male-specific lethality. Remarkably, rare live-born males expressed DUX4 RNA in the retina and presented a retinal vascular telangiectasia. By using doxycycline to induce DUX4 expression in satellite cells, we observed impaired myogenesis in vitro and in vivo. This mouse model, which shows pathologies due to FSHD-related D4Z4 sequences, is likely to be useful for testing anti-DUX4 therapies in FSHD

Dorsoventral Patterning in Hemichordates: Insights into Early Chordate Evolution

We have compared the dorsoventral development of hemichordates and chordates to deduce the organization of their common ancestor, and hence to identify the evolutionary modifications of the chordate body axis after the lineages split. In the hemichordate embryo, genes encoding bone morphogenetic proteins (Bmp) 2/4 and 5/8, as well as several genes for modulators of Bmp activity, are expressed in a thin stripe of ectoderm on one midline, historically called “dorsal.” On the opposite midline, the genes encoding Chordin and Anti-dorsalizing morphogenetic protein (Admp) are expressed. Thus, we find a Bmp-Chordin developmental axis preceding and underlying the anatomical dorsoventral axis of hemichordates, adding to the evidence from Drosophila and chordates that this axis may be at least as ancient as the first bilateral animals. Numerous genes encoding transcription factors and signaling ligands are expressed in the three germ layers of hemichordate embryos in distinct dorsoventral domains, such as pox neuro, pituitary homeobox, distalless, and tbx2/3 on the Bmp side and netrin, mnx, mox, and single-minded on the Chordin-Admp side. When we expose the embryo to excess Bmp protein, or when we deplete endogenous Bmp by small interfering RNA injections, these expression domains expand or contract, reflecting their activation or repression by Bmp, and the embryos develop as dorsalized or ventralized limit forms. Dorsoventral patterning is independent of anterior/posterior patterning, as in Drosophila but not chordates. Unlike both chordates and Drosophila, neural gene expression in hemichordates is not repressed by high Bmp levels, consistent with their development of a diffuse rather than centralized nervous system. We suggest that the common ancestor of hemichordates and chordates did not use its Bmp-Chordin axis to segregate epidermal and neural ectoderm but to pattern many other dorsoventral aspects of the germ layers, including neural cell fates within a diffuse nervous system. Accordingly, centralization was added in the chordate line by neural-epidermal segregation, mediated by the pre-existing Bmp-Chordin axis. Finally, since hemichordates develop the mouth on the non-Bmp side, like arthropods but opposite to chordates, the mouth and Bmp-Chordin axis may have rearranged in the chordate line, one relative to the other.</p

BTZ black holes and the near-horizon geometry of higher-dimensional black holes

We investigate the connection between the BTZ black holes and the near-horizon geometry of higher-dimensional black holes. Under mild conditions, we show that (i) if a black hole has a global structure of the type of the non-extremal Reissner-Nordstrom black holes, its near-horizon geometry is $AdS_2$ times a sphere, and further (ii) if such a black hole is obtained from a boosted black string by dimensional reduction, the near-horizon geometry of the latter contains a BTZ black hole. Because of these facts, the calculation of the Bekenstein-Hawking entropy and the absorption cross-sections of scalar fields is essentially reduced to the corresponding calculation in the BTZ geometry under appropriate conditions. This holds even if the geometry is not supersymmetric in the extremal limit. Several examples are discussed. We also discuss some generalizations to geometries which do not have $AdS$ near the horizon.Comment: 19 pages, LaTex, (v2) a comment on black holes with 2 and 3 charges added, (v3) some phrases made more precise, references added, minor changes; version to appear in Phys. Rev.

Loss of peroxiredoxin-2 exacerbates eccentric contraction-induced force loss in dystrophin-deficient muscle

Force loss in skeletal muscle exposed to eccentric contraction is often attributed to injury. We show that EDL muscles from dystrophin-deficient mdx mice recover 65% of lost force within 120 min of eccentric contraction and exhibit minimal force loss when the interval between contractions is increased from 3 to 30 min. A proteomic screen of mdx muscle identified an 80% reduction in the antioxidant peroxiredoxin-2, likely due to proteolytic degradation following hyperoxidation by NADPH Oxidase 2. Eccentric contraction-induced force loss in mdx muscle was exacerbated by peroxiredoxin-2 ablation, and improved by peroxiredoxin-2 overexpression or myoglobin knockout. Finally, overexpression of γcyto- or βcyto-actin protects mdx muscle from eccentric contraction-induced force loss by blocking NADPH Oxidase 2 through a mechanism dependent on cysteine 272 unique to cytoplasmic actins. Our data suggest that eccentric contraction-induced force loss may function as an adaptive circuit breaker that protects mdx muscle from injurious contractions

Functional Substitution by TAT-Utrophin in Dystrophin-Deficient Mice

James Ervasti and colleagues show that injection of a truncated form of utrophin transduced all tissues examined, integrated with members of the dystrophin complex, and reduced serum levels of creatine kinase in a mouse model of muscular dystrophy