79297 research outputs found
Sort by
Impact of Voluntary Exercise on Systemic Inflammation in a 2? Hit Model of Heart Failure With Preserved Ejection Fraction
Get PDFPOTENTIAL TARGETS FOR CARDIAC FIBROSIS AFTER MYOCARDIAL INFARCTION
No full textIn response to myocardial infarction (MI), cardiac fibroblasts (CFs) activate, proliferate, and differentiate into myofibroblasts that produce extracellular matrix (ECM) to form a stabilizing scar. While essential for repair, prolonged CFs activation can drive maladaptive remodeling. Thus, understanding CF heterogeneity and its regulation is key to limiting fibrosis without disrupting healing.
Smooth muscle alpha-actin (SMαA), encoded by Acta2, is a common marker of myofibroblast differentiation, but its functional role in cardiac fibroblasts and post-MI repair was unclear. In Chapter 2, we addressed this by creating a tamoxifen-inducible, cardiac fibroblast-specific Acta2 knockout (KO) mouse model. Surprisingly, Acta2 deletion did not affect post-MI survival, cardiac function, or infarct histology. Acta2-null myofibroblasts retained normal proliferation, migration, contractility, and filamentous actin levels. This was linked to compensatory upregulation of other actin isoforms, especially Actg2 and Acta1, with cytoplasmic isoforms predominating. In addition, we found that myocardin-related transcription factor-A is critical for myofibroblast differentiation but is not required for the compensatory effects of non-Acta2 isoforms. These findings indicate that Acta2 is not essential for cardiac fibroblast function or post-MI repair due to functional redundancy among actin isoforms.
In chapter 3, snMultiomic profiling across post-MI stages identified Runx1 as a key regulator of cardiac fibroblast (CF) dynamics. Using a fibroblast-specific Runx1 KO model (Pdgfrα-CreERT2), we observed changes in CF and immune cell gene expression over time. By day 3 post-MI, wild-type hearts showed enrichment of cell cycle and catabolic pathways compared to Runx1 KO. By day 7, Runx1 KO reduced Pleiotrophin (Ptn) expression, affecting CF–immune interactions, and downregulated chondrogenic genes including Comp, Acan, Col2a1, and Lox. GRN and epigenetic analysis confirmed Comp, Ptn, Lox, Cemip, and postn are direct Runx1 targets via promoter and enhancer regulation. Interestingly, Comp expression remained suppressed in populations lacking Runx2 compensation at 4 weeks. Functionally, Runx1 deletion in CFs reduced cardiac rupture in males, improved cardiac function and hypertrophy, and lowered SMαA expression at day 7. Runx1 deficiency reduced CF proliferation and chondrogenic capacity, while maintaining their motility, contractile function, and ECM-stabilizing properties
Gumbo Yearbook, Class of 2025
Get PDFThe Gumbo yearbook chronicles the entire academic year at LSU. In words and especially photos, the Gumbo shows the people, places, and events that make each year unique. In addition to formal portraits of schools and departments, the book contains hundreds of snapshots of students with their friends and dozens of pages showcasing organizations.https://repository.lsu.edu/gumbo/1141/thumbnail.jp
Synopsis of Mesoamerican Freziera (Pentaphylacaceae, Ericales)
No full textA synopsis of Freziera is presented for Mesoamerica. We document 14 species of Freziera for Mesoamerica, 10 of which are endemic to the region. We also describe three new species: F. aguilarii D.Santam., F. dauphinii D.Santam., and F. jefensis D.Santam. that we assess as Vulnerable to extinction (CR), Near Threatened (NT), and Endangered (E) respectively. The newly described species had previously been considered to be conspecific to F. calophylla, or F. grisebachii. We also resurrect F. lancifolia, which has previously been treated as a synonym of F. grisebachii, but which we consider to be morphologically distinct. In addition, we designate a lectotype for F. guatemalensis. Distinctive characters, distribution, habitat, phenology, and illustrations are provided. We also provide a summary of the morphology, natural history, common names, and uses for Freziera species in Mesoamerica
Behavioural infection tolerance of malaria is negatively correlated with pro-inflammatory cytokine expression in the brain of an invasive songbird
No full textInvasive species are often freed from the co-evolved parasites of their native range (“enemy release hypothesis”), leaving little benefit for the host to induce self-harming inflammatory responses against novel pathogens in the invading range. Instead, selection may favour the allocation of energetic resources to traits that facilitate growth and reproduction to increase competitive ability (“evolution of increased competitive ability hypothesis”). In extension of these hypotheses, we tested whether the globally invasive house sparrow (Passer domesticus; n = 21) exhibits sickness behaviours during acute experimental inoculation with Plasmodium relictum. Because sickness behaviours are a consequence of inflammation, we quantified cytokine expression in the liver and brain. Overall, we did not detect any changes in feeding duration, preening duration, or activity in malaria-infected sparrows (n = 10) during acute malaria infection, and infected sparrow behaviour did not differ from malaria-resistant sparrows (n = 5) or sham controls (n = 6). However, pro-inflammatory IFN-γ expression in the brain, but not the liver, was negatively correlated with infected sparrow activity, suggesting individuals that mount strong inflammatory responses are more likely to show sickness behaviours. Disease transmission is often linked with host behaviour; if invasive species behaviourally tolerate infection and maintain normal activity and sociality, they may disproportionately facilitate the spread of disease
Synthesis of bis-quaternary centers at the α-positions of cyclohexanones via Copper(I)-Catalyzed Claisen rearrangement: The substituent effect from the opposing α-quaternary center on diastereoselectivity
No full textWe report the synthesis of bis-quaternary centers at the α-positions of cyclohexanones. In this chemistry, ionization of an α-hydroxy allyl vinyl ether with Cu(MeCN)4BF4 catalyst at room temperature formed an allyloxy allyl cation that was captured by indole in a regioselective manner to create an α-quaternary center. Upon heating, the Claisen rearrangement occurred in situ to produce a second quaternary center at the opposing α′-position, thereby furnishing the targeted bis-quaternary center motif. Studies in this article examined the alkyl substituents at the α-carbon and their effect on diastereoselectivity of the Claisen rearrangement. Interestingly, the copper catalyst enhanced the trans delivery of the allyl group with respect to the indole versus the background diastereoselectivity of the uncatalyzed reaction
Modulating the Aqueous Micellar Reorganization of Sequence-Defined Ionic Peptoid Block Copolymers by Ionizable Monomer Position and Solution pH
Get PDFThe micellar aggregation of singly charged sequence-defined ionic peptoid block copolymers can be finely tuned by adjusting the position of the ionizable monomer along the chain and varying the solution pH. The pH-induced structural reorganization of these micelles was found to depend on the position of the ionizable monomer along the chain, influencing the balance of the hydrophobic interactions, excluded volume effect, and electrostatic forces (i.e., charge repulsion, solvation of the ionic monomers, counterion association) that govern the micellar structure. As the solution pH increases, positioning the ionizable monomer closer to the junction of the hydrophobic and hydrophilic blocks causes a larger reduction in the micellar size and aggregation number across two distinct regimes. In contrast, placing the ionizable monomer at the terminus of the hydrophilic block results in a smaller reduction in the micellar size and aggregation number over three regimes. This study provides new insights into leveraging the strategic positioning of ionizable monomers to design stimuli-responsive nanoassemblies capable of programmable structural reorganization
Rethinking the Lake History of Taylor Valley, Antarctica During the Ross Sea I Glaciation
Get PDFThe Ross Sea I glaciation, marked by the northward advance of the Ross Ice Sheet (RIS) in the Ross Sea, east Antarctica, corresponds with the last major expansion of the West Antarctic Ice Sheet during the last glacial period. During its advance, the RIS was grounded along the southern Victoria Land coast, completely blocking the mouths of several of the McMurdo Dry Valleys (MDVs). Several authors have proposed that very large paleolakes, proglacial to the RIS, existed in many of the MDVs. Studies of these large paleolakes have been key in the interpretation of the regional landscape, climate, hydrology, and glacier and ice sheet movements. By far the most studied of these large paleolakes is Glacial Lake Washburn (GLW) in Taylor Valley. Here, we present a comprehensive review of literature related to GLW, focusing on the waters supplying the paleolake, signatures of the paleolake itself, and signatures of past glacial movements that controlled the spatial extent of GLW. We find that while a valley-wide proglacial lake likely did exist in Taylor Valley during the early stages of the Ross Sea I glaciation, during later stages two isolated lakes occupied the eastern and western sections of the valley, confined by an expansion of local alpine glaciers. Lake levels above ~140 m asl were confined to western Taylor Valley, and major lake level changes were likely driven by RIS movements, with climate variables playing a more minor role. These results may have major implications for our understanding of the MDVs and the RIS during the Ross Sea I glaciation
Weather Impacts on Specialty Fruit Wholesale Prices
Get PDFThis article investigates the relationship between temperature and precipitation variability and wholesale specialty fruit prices in the United States. Using fixed-effects panel regression and a comprehensive dataset of monthly price observations across ten major U.S. wholesale markets (Atlanta, Baltimore, Boston, Chicago, Detroit, Los Angeles, Miami, New York, Philadelphia and San Francisco) from 2000 to 2019, we examine how weather fluctuations affect wholesale market prices for five fruits including apples, avocados, grapes, oranges, and strawberries. Our analysis categorizes temperature into discrete bins representing the number of days per month within specific temperature ranges. The results show that extreme temperatures, particularly above 80°F and below 30°F, significantly influence wholesale fruit prices. Days exceeding 80°F are associated with statistically significant price increases of up to 0.45%. Days below 30°F are also linked to price increases of 0.14% to 0.17%. Commodity-specific responses differ. Strawberries exhibit the most negative price response under heat, with prices falling by 1.14% above 80°F. Apples and oranges, in contrast, experience modest price gains. Avocados show a particularly strong price increase of 1.15% during extreme heat. These findings suggest differential sensitivity across fruit types to temperature extremes. While the underlying mechanisms are not directly tested, the observed patterns could relate to differences in perishability, storage requirements, or market structure