31 research outputs found
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Aortic pathology from protein kinase G activation is prevented by an antioxidant vitamin B12 analog.
People heterozygous for an activating mutation in protein kinase G1 (PRKG1, p.Arg177Gln) develop thoracic aortic aneurysms and dissections (TAAD) as young adults. Here we report that mice heterozygous for the mutation have a three-fold increase in basal protein kinase G (PKG) activity, and develop age-dependent aortic dilation. Prkg1R177Q/+ aortas show increased smooth muscle cell apoptosis, elastin fiber breaks, and oxidative stress compared to aortas from wild type littermates. Transverse aortic constriction (TAC)-to increase wall stress in the ascending aorta-induces severe aortic pathology and mortality from aortic rupture in young mutant mice. The free radical-neutralizing vitamin B12-analog cobinamide completely prevents age-related aortic wall degeneration, and the unrelated anti-oxidant N-acetylcysteine ameliorates TAC-induced pathology. Thus, increased basal PKG activity induces oxidative stress in the aorta, raising concern about the widespread clinical use of PKG-activating drugs. Cobinamide could be a treatment for aortic aneurysms where oxidative stress contributes to the disease, including Marfan syndrome
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A plasma membrane-associated form of the androgen receptor enhances nuclear androgen signaling in osteoblasts and prostate cancer cells.
Androgen binding to the androgen receptor (AR) in the cytoplasm induces the AR to translocate to the nucleus, where it regulates the expression of target genes. Here, we found that androgens rapidly activated a plasma membrane-associated signaling node that enhanced nuclear AR functions. In murine primary osteoblasts, dihydrotestosterone (DHT) binding to a membrane-associated form of AR stimulated plasma membrane-associated protein kinase G type 2 (PKG2), leading to the activation of multiple kinases, including ERK. Phosphorylation of AR at Ser515 by ERK increased the nuclear accumulation and binding of AR to the promoter of Ctnnb1, which encodes the transcription factor β-catenin. In male mouse osteoblasts and human prostate cancer cells, DHT induced the expression of Ctnnb1 and CTNN1B, respectively, as well as β-catenin target genes, stimulating the proliferation, survival, and differentiation of osteoblasts and the proliferation of prostate cancer cells in a PKG2-dependent fashion. Because β-catenin is a master regulator of skeletal homeostasis, these results explain the reported male-specific osteoporotic phenotype of mice lacking PKG2 in osteoblasts and imply that PKG2-dependent AR signaling is essential for maintaining bone mass in vivo. Our results suggest that widely used pharmacological PKG activators, such as sildenafil, could be beneficial for male and estrogen-deficient female patients with osteoporosis but detrimental in patients with prostate cancer
STBase: one million species trees for comparative biology.
Comprehensively sampled phylogenetic trees provide the most compelling foundations for strong inferences in comparative evolutionary biology. Mismatches are common, however, between the taxa for which comparative data are available and the taxa sampled by published phylogenetic analyses. Moreover, many published phylogenies are gene trees, which cannot always be adapted immediately for species level comparisons because of discordance, gene duplication, and other confounding biological processes. A new database, STBase, lets comparative biologists quickly retrieve species level phylogenetic hypotheses in response to a query list of species names. The database consists of 1 million single- and multi-locus data sets, each with a confidence set of 1000 putative species trees, computed from GenBank sequence data for 413,000 eukaryotic taxa. Two bodies of theoretical work are leveraged to aid in the assembly of multi-locus concatenated data sets for species tree construction. First, multiply labeled gene trees are pruned to conflict-free singly-labeled species-level trees that can be combined between loci. Second, impacts of missing data in multi-locus data sets are ameliorated by assembling only decisive data sets. Data sets overlapping with the user's query are ranked using a scheme that depends on user-provided weights for tree quality and for taxonomic overlap of the tree with the query. Retrieval times are independent of the size of the database, typically a few seconds. Tree quality is assessed by a real-time evaluation of bootstrap support on just the overlapping subtree. Associated sequence alignments, tree files and metadata can be downloaded for subsequent analysis. STBase provides a tool for comparative biologists interested in exploiting the most relevant sequence data available for the taxa of interest. It may also serve as a prototype for future species tree oriented databases and as a resource for assembly of larger species phylogenies from precomputed trees
WalkRollMap.org: Crowdsourcing barriers to mobility
Walking is a simple way to improve health through physical activity. Yet many people experience barriers to walking from a variety of physical, social, and psychological factors that impact their mobility. A challenge for managing and studying pedestrian environments is that barriers often occur at local scales (e.g., sidewalk features), yet such fine scale data on pedestrian facilities and experiences are often lacking or out of date. In response, our team developed WalkRollMap.org an online mapping tool that empowers communities by providing them with tools for crowdsourcing their own open data source. In this manuscript we highlight key functions of the tool, discuss initial approaches to community outreach, and share trends in reporting from the first nine months of operation. As of July 27, 2022, there have been 897 reports, of which 53% served to identify hazards, 34% missing amenities, and 14% incidents. The most frequently reported issues were related to sidewalks (15%), driver behavior (19%), and marked crosswalks (7%). The most common suggested amenities were sidewalks, marked crosswalks, connections (i.e., pathways between streets), and curb cuts. The most common types of incidents all included conflicts with vehicles. Data compiled through WalkRollMap.org offer unique potential for local and timely information on microscale barriers to mobility and are available for use by anyone as data are open and downloadable
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The Antioxidant/Nitric Oxide-Quenching Agent Cobinamide Prevents Aortic Disease in a Mouse Model of Marfan Syndrome.
Major pathologic changes in the proximal aorta underlie the life-threatening aortic aneurysms and dissections in Marfan Syndrome; current treatments delay aneurysm development without addressing the primary pathology. Because excess oxidative stress and nitric oxide/protein kinase G signaling likely contribute to the aortopathy, we hypothesized that cobinamide, a strong antioxidant that can attenuate nitric oxide signaling, could be uniquely suited to prevent aortic disease. In a well-characterized mouse model of Marfan Syndrome, cobinamide dramatically reduced elastin breaks, prevented excess collagen deposition and smooth muscle cell apoptosis, and blocked DNA, lipid, and protein oxidation and excess nitric oxide/protein kinase G signaling in the ascending aorta. Consistent with preventing pathologic changes, cobinamide diminished aortic root dilation without affecting blood pressure. Cobinamide exhibited excellent safety and pharmacokinetic profiles indicating it could be a practical treatment. We conclude that cobinamide deserves further study as a disease-modifying treatment of Marfan Syndrome
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High blood pressure and lost EDHF response in redox dead Cys42Ser PKGIα knock-in mouse
Illustration of the multree reduction algorithm [37].
<p>The upper tree is a multree, i.e., it has at least one label that is found on more than one terminal. Furthermore, it displays quartets (subtrees on four taxa) that are in conflict: <i>BD</i>|<i>EC</i> conflicts with <i>BC</i>|<i>DE</i>. The reduced form of the tree, below, is a singly-labeled tree. This is a conservative statement about species relationships in the sense that it eliminates conflict (while introducing no new information).</p
Summary statistics for the three kinds of data sets.
<p>Summary statistics for the three kinds of data sets.</p