bluuebunny/crossref_metadata_2025_split huggingface dataset:
All stressed out: physical tension drives mesenchymal‐to‐epithelial transition in heart progenitor cells
Authors: Davidson Lance , Jackson Timothy R , Kim Hye Young 
Published: June 2021

Proper heart formation involves coordinated movements by endoderm and mesenchymal heart progenitor cells (HPCs). Bilateral populations of HPCs begin these movements as mesenchymal cells but transition to epithelial before they form the ventral heart trough. Originating from the lateral plate mesoderm in the frog Xenopus laevis HPCs first localize aPKC to a putative apical surface then assemble apical junctions rich in ZO‐1 well in advance of reaching the ventral midline. Ex vivo and intra vital imaging reveals that cells undergoing MET exhibit stereotypical changes in collective migration and traction forces. This “phase‐transition” supports observations in chicken and zebrafish and suggest that mesenchymal HPCs are initially carried to the midline by endoderm but complete their movements as epithelia via traction‐mediated migration. To understand the role of mechanics in the spatial and temporal control of this mesenchymal‐to‐epithelial transition (MET) we carried out a biomechanical analysis of the heart forming region (HFR). Time‐lapse imaging of the HFR reveals a complex pattern of shape change, first contracting in the anterior‐posterior direction then elongating. Strain maps from this analysis combined with biomechanical measurements of tissue compliance with microaspiration reveal MET coincides with peak levels of tissue stress in the HFR suggesting mechanical cues from the microenvironment are responsible for inducing MET in the HPCs. To test such a role for tissue stress we took three different approaches to modulating mechanics: 1) overexpression of constitutive active Rho‐GEF, 2) incubation with activators and inhibitors of cell contractility, and 3) exogenously applied strain. Overexpression of contractility by targeted mRNA injections revealed that MET could be driven non‐cell autonomously by stiffening endoderm. Transient disruptions in MET with small molecule inhibitors and activators of contractility revealed decreased contractility could inhibit while increased contractility could precociously induce MET. Finally, using only physical means to strain the HFR we were also able to induce early MET. Each of these three perturbations of the mechanical microenvironment resulted in specific defects in the architecture of the larval heart which manifest in defects in cardiac output. Thus, using biophysical and cell biological methods we identified endogenous changes in the mechanical microenvironment in the heart forming region (HFR) that appear to drive HPCs into a mesenchymal‐to‐epithelial transition and how lesions in that regulation impact heart structure and function.Support or Funding InformationNational Science Foundation (CBET‐1547790), National Institutes of Health (R01HD044750; R56HL13495) and the Cardiovascular Bioengineering Training Program (NIH NHLBI T32 HL076124).
Mechanistic pathways to unusual outcomes in reactions of iron‐dependent oxygenases
Authors: Bollinger J. Martin , Krebs Carsten 
Published: June 2021

Non‐heme‐iron (NH‐Fe) enzymes activate O2 for an array of biomedically, agriculturally, and environmentally important oxidation reactions. Our past decade's work has characterized iron(IV)‐oxo (ferryl) complexes in several such NH‐Fe enzymes.1 In all such systems that transform aliphatic carbon centers, the ferryl complexes generate substrate radicals by abstracting hydrogen (H•),2–6 leading to formation of new C–O,2–4 C–Cl/Br,5,6 or C–S bonds.1 Motivated by our success in rationalizing the divergent outcomes of the NH‐Fe‐ and 2‐ (oxo)glutarate‐dependent aliphatic hydroxylases and halogenases,7 we now seek both to exploit the ferryl manifold for novel, unnatural carbon‐functionalization reactions8 and to explain the structural and mechanistic bases for several other natural reaction types – including 1,3‐dehydrogenation of an alcohol to epoxide,9 stereo‐inversion of a chiral carbon,10 and desaturation and cleavage of C–C bonds – that are initiated by ferryl complexes in other NH‐Fe enzymes. Insight obtained will inform development of new biocatalytic synthetic routes and combinatorial design of new antibiotic and anticancer drugs.Support or Funding InformationNational Institutes of Health GM118812, GM113106, and GM069657; National Science Foundation CHE‐0724084 and MCB‐0642058.
Energy restriction upregulates circulating myomiR expression in vivo and in vitro
Authors: Margolis Lee M , Rivas Dontato A , Pasiakos Stefan M , McClung James P , Ceglia Lisa , Fielding Roger A 
Published: June 2021

Energy restriction (ER)‐induced weightloss attenuates the rate of protein synthesis, which over time can result inreductions in skeletal muscle mass. Recently, changes in the expression of circulating muscle‐specific microRNA (c‐myomiR)have been suggested to reflect rates of protein synthesis. However, whether an increased expression ofc‐myomiR are associated with lower rates of protein synthesis remains undefined. The present investigation sought to determine whether ER influences c‐myomiR expression, and if changes in c‐myomiR are associated with rates of protein synthesis both in vivo (humans) and in vitro (cultured myocytes). Sixteen older (64 ± 2 yrs) overweight (28.5 ±1.2 kg·m−2) males enrolled in this 35‐day controlled feedingtrial. A 7‐day weight maintenance (WM)period was followed by 28 days of 30% ER; whole‐body protein turnover (15N‐glycine)and c‐myomiR (miR‐1–3p, miR‐133a‐3p, miR‐133b, miR‐206) expression was assessed by RT‐qPCR at the conclusions of WM and ER. Participants lost 4.4 ± 0.3 kg body mass during ER (P < 0.05). Overall, ER upregulated c‐myomiR expression compared to WM (P < 0.05). Expression ofc‐myomiR was inversely associated (r= −0.700, P < 0.05) with whole‐body protein synthesis after ER. Similarly, assessing the expression of c‐myomiR obtained from media that C2C12myotubes were cultured; ER increased c‐myomiR expression by 2.9 ± 0.1 fold and lowered the protein synthesis rate by 2.1 ±0.2 fold compared to control. Corroboration of in vitro and in vivo findings indicates that increased expressions of c‐myomiR maybe noninvasive markers reflective of ER‐induced reductions in the rate protein synthesis.Support or Funding InformationThis material is based on the work supported by the U.S. Department of Agriculture(USDA), under agreement No. 58‐1950‐4‐003 and the US Army Medical Research and Material Command. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the USDA. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. The study was also supported by the Boston Claude D. Pepper Center Older American Independence Centers (OAIC;1P30AG031679). L.M.M is supported by T32NIDDK training grant # 5T32DK062032‐23. D.A.R. is supported by NIA K01 award # KAG047247A‐A1.
Serum 24,25‐dihydroxyvitamin D Is Suppressed Across Pregnancy In Adolescents with Low Vitamin D Status
Authors: Best Cora M. , Pressman Eva K. , Cooper Elizabeth , Queenan Ruth Anne , O'Brien Kimberly O. 
Published: June 2021

BackgroundLow maternal serum 25(OH)D has been associated with preeclampsia, low birth weight, and offspring bone health. Serum concentrations of the hormone 1,25(OH)2D (calcitriol) rise in pregnancy, yet the importance of calcitriol and parathyroid hormone (PTH) to calcium homeostasis during pregnancy is uncertain. Possible alterations in serum 24,25(OH)2D, the catabolite of 25(OH)D, remain largely unexplored across gestation, and assessment of 24,25(OH)2D could improve understanding of pregnancy adaptations in vitamin D metabolism.MethodsWe supplemented 79 pregnant adolescents at risk of vitamin D inadequacy with 2000 International Units (IU) or 200 IU of vitamin D3 daily and sought to determine how the serum 25(OH)D response related to circulating calcitriol, 24,25(OH)2D, and PTH. Serum was collected at study entry, midway through the study, and delivery. We measured serum 25(OH)D, calcitriol, and 24,25(OH)2D by LC‐MS/MS and PTH by immunoassay. We used pre‐post and longitudinal analyses to assess change in serum markers.ResultsAt study entry (18 ± 5 wk gestation, mean ± sd), serum 25(OH)D was 25 ± 9 ng/ml, and it changed 0.5 ± 10 ng/ml between entry and delivery. Calcitriol was elevated above non‐pregnant levels at entry and peaked in the 3rd trimester. Calcitriol and 25(OH)D were weakly correlated at delivery, yet baseline and change in 25(OH)D did not predict calcitriol concentrations across pregnancy. In contrast, serum 24,25(OH)2D and 25(OH)D were highly correlated throughout pregnancy (r≥0.85, p<0.001), but change in 24,25(OH)2D relative to that of 25(OH)D varied by baseline vitamin D status. When serum 25(OH)D increased any amount over pregnancy, the increase in 24,25(OH)2D was attenuated in teens with baseline 25(OH)D <20 ng/ml (n=27) vs. ≥20 ng/ml (n=52). Change in 24,25(OH)2D was related to change in serum calcium (r=0.40, p=0.001). Change in the 1,25(OH)2D/24,25(OH)2D ratio was positively related to change in serum PTH (r=0.30, p=0.02), a hormone that elevates 1,25(OH)2D and suppresses the renal 24‐hydroxylase in the non‐pregnant state. Those with baseline 25(OH)D <20 ng/ml drove this association of 1,25(OH)2D/24,25(OH)2D and PTH (p=0.01).ConclusionsOur results imply that production of 24,25(OH)2D across pregnancy is suppressed/constrained when 25(OH)D supply is limited, perhaps to preserve 25(OH)D and adequate production of calcitriol. Serum 24,25(OH)2D and vitamin D metabolite ratios may be useful indicators of vitamin D and calcium homeostasis during pregnancy.Support or Funding InformationThis research was supported by USDA grant 2011‐03424 and NIH award T32‐DK007158. Content does not represent the official views of the NIH.
Impact of Maternal Obesity and High Fat Diet during Pregnancy and Lactation on Offspring Body Weight, Immune Function, and Resistance to Influenza Infection
Authors: Guo Weimin , Wu Dayong , Li Lijun , Smith Donald E. , Meydani Simin Nikbin 
Published: June 2021

Studies have suggested that obesity is associated with immune dysfunction and higher risk of infection. Maternal obesity is thought to affect body weight which may in turn alter immune function in offspring. However, the relative contribution of maternal factors (maternal obesity versus high fat diet during pregnancy and lactation) to the changes in body weight, immune function, and response to infection in the offspring is not well‐understood. To address this, we fed outbred 1‐mo old female CD‐1 mice a high fat (HF, 45%) diet or a low fat (LF, 10%) control diet to induce obesity. After 5‐mo on the respective diets, mice fed the high fat diet had considerable variation in weight gain. Thus, based on body weight, we further divided the mice in the HF group into two sub‐groups: obesity‐prone (high fat obese, HF‐O) and obesity‐resistant (high fat lean, HF‐L) groups. This provided us with the opportunity to separate the impact of obesity from that of high fat diet during pregnancy. Dams in all 3 groups (LF, HF‐O, HF‐L) were mated with 3‐mo old male CD1 mice fed a standard chow diet. All dams continued to be fed their respective diet during pregnancy and lactation. The offspring born to LF, HF‐L, and HF‐O dams were fed standard chow and monitored for their body weight. At 10‐mo of age, they were infected with influenza virus (A/Puerto Rico/8/34) and then monitored daily for symptoms until day 8 post‐infection when they were euthanized and tissues collected for analysis. Results showed that while offspring in all groups exhibited post‐infection weight loss, offspring of HF‐L group had the most weight loss. Further, both male and female offspring born to HF‐L dams had significantly more severe lung pathology compared to those born to HF‐O dams. In addition, female offspring born to HF‐O dams had significantly higher CD3 or CD3/CD28‐stimulated lymphocyte proliferation than those born to LF dams, and also had significantly lower % cytotoxic T cells (CD8+ cells) than those born to LF dams and HF‐L dams. Percentage of total T cells (CD3+), helper T cells (CD4+), and regulatory T cells (CD4+CD25+) in spleen were significantly lower in the male offspring of HF‐O dams compared with the male offspring of HF‐L dams. Taken together our results showed that maternal obesity, independent of high fat diet, influences immune response and resistance to influenza infection. Contrary to our expectation, offspring born to obese mothers had less pathology and weight loss and better T cell function following influenza infection. While the underlying mechanisms of varied resistance to influenza infection are not completely understood, our results suggest that they might be, at least in part, related to differences in T cell profile and function.Support or Funding InformationSupported by the USDA under contract #58‐1950‐4‐003
Both paternal exercise and healthy diet are required to protect offspring from high fat diet‐induced obesity and type 2 diabetes risk in mice
Authors: Claycombe Kate J , Krout Danielle , Garcia Rolando , Roemmich James 
Published: June 2021

ObjectivePaternal eating and physical activity behaviors peri‐conception may influence offspring obesity and type 2 diabetes (T2D) risk. A recent study showed that paternal exercise increased offspring susceptibility to obesity when the offspring consumed a high fat (HF) diet. However, it is not yet known how paternal HF diet and paternal exercise interact to alter offspring adiposity and T2D risk.MethodThree week old male C57BL/6J mice were fed a control normal fat (NF) diet (16% fat) or a HF diet (45% fat) and provided voluntary wheel running exercise or cage activity (sedentary) for 3 months prior to mating with NF diet‐fed dams. After weaning, male offspring were fed NF or HF diet for 3 months.ResultsCompared to offspring born from cage‐active fathers fed a NF diet, offspring of cage‐active fathers fed a HF diet had decreased body weights at postnatal days 5, 12, and 21 as well as increased insulin resistance at 5 months of age. Paternal HF diet‐induced changes in offspring body weights early in post‐natal life and insulin resistance in adulthood were abolished when fathers exercised. In addition, paternal exercise prevented postnatal HF diet‐induced body and adipose tissue weight increases in offspring at 5 months of age, but only when fathers were fed NF diets.ConclusionThese findings suggest that paternal exercise reduces risk for adiposity and insulin resistance in offspring exposed to a HF diet, but only when fathers consumed a NF diet and exercised. A paternal NF diet alone, without paternal exercise, did not protect HF diet‐induced body and adipose tissue weight gains in offspring. Future studies will determine physiological mechanisms underlying beneficial effects of combined exercise and diet through paternal lineage.Support or Funding InformationThis work was supported by USDA Agricultural Research Service Project #3062‐51000‐052‐00D.
Alveolar Macrophage Heterogeneity As A Driver Of Age‐Related Responses To Influenza A Infection
Authors: McQuattie‐Pimentel Alexandra Cristina , Chen Ching‐I , Reyfman Paul , Morales‐Nebreda Luisa , Walter James , Chi Monica , Ridge Karen , Perlman Harris , Budinger GR Scott , Misharin Alexander 
Published: June 2021

RationaleSeasonal influenza A virus infection causes at least 20,000–50,000 deaths in the United States each year and causes disproportionate morbidity and mortality in older individuals. We and others have found similarly disproportionate mortality in aged mice infected with influenza A. An important role for alveolar macrophages in the response to influenza A infection is recognized. Strategies to therapeutically target alveolar macrophages during lung injury have considered that they are a single population of monocyte‐derived cells. This paradigm has been challenged by studies that identified tissue‐resident alveolar macrophages (TR‐AM) as highly specialized cells that populate the lung shortly after birth and persist over the lifespan.MethodsWe aged bone marrow chimeric C57Bl/6 (CD45.1 donor into CD45.2 host) mice generated with thoracic shielding followed by busulfan depletion of the remaining bone marrow. The resulting chimeric mice (>99% donor monocytes in blood, >99 % recipient in tissue resident alveolar macrophages), were treated with influenza A (A/WSN/33) virus, or bleomycin.ResultsSevere injury early in life alters the alveolar macrophage landscape during aging. We treated shielded‐bone‐marrow chimeric mice with influenza A or bleomycin and measured the ratio between Mo‐AM and TR‐AM 10 months later. We found that TR‐AM were remarkably stable, constituting >95% of alveolar macrophages in naïve mice at 14 months of age. In contrast, in mice infected with influenza A (A/WSN/33) virus, 100pfu at 8 weeks post bone marrow transfer (4 months of age), approximately 50% of the alveolar macrophages were monocyte‐derived 10 months later. To determine whether this finding was unique to influenza A, we treated a separate cohort of shielded‐bone‐marrow chimeric mice with bleomycin and obtained similar results. Next, we sought to determine whether the differences in gene expression between TR‐AM and Mo‐AM we observed during injury and fibrosis persisted over the lifespan. Ten months after bleomycin treatment or influenza A infection, TR‐AM and Mo‐AM were not disgtinguishable by flow cytometry. A comparison of the transcriptomes of TR‐AM and Mo‐AM 10 months after bleomycin administration revealed only 101 differentially expressed genes.ConclusionThis finding suggests that a severe injury early in life can permanently reshape the alveolar macrophage landscape with respect to its developmental origins. If monocyte‐derived alveolar macrophages differ in their response to challenge, this might explain some of the age‐related susceptibility to influenza A infection.Support or Funding InformationAG049665, HL071643, ES013995, The Veterans Administration, DOD W81XWH‐15‐1‐0215
What Do People Eat When They Don't Eat Meat? An Evaluation of Dietary Quality Using the National Health and Nutrition Examination Survey (NHANES), 2007–2012
Authors: Conrad Zach , Karlsen Micaela , Chui Kenneth , Jahns Lisa 
Published: June 2021

ObjectiveTo compare diet quality scores between adult non‐meat eaters and meat eaters, and to compare the consumption of diet components across quintiles of diet quality.DesignCross‐sectional analysis. Healthy Eating Index‐2010 (HEI‐2010) and Alternative Healthy Eating Index‐2010 (AHEI‐2010) were used to assess mean diet quality. Differences in consumption of diet components between quintiles of diet quality were tested using post hoc Wald tests.SettingThe National Health and Nutrition Examination Survey (NHANES), 2007–2012.SubjectsThe sample consisted of 16,688 respondents ≥20 y, including 281 individuals that reported not consuming meat, fowl, or seafood on two non‐consecutive days of dietary recall. Dietary data were obtained from one dietary recall per individual.ResultsNon‐meat eaters had substantially greater HEI‐2010 and AHEI‐2010 scores compared to meat eaters (P<0.05). Among non‐meat eaters, mean consumption across HEI‐2010 quintiles demonstrated different (P<0.05) amounts of empty calories, whole fruit, and plant proteins. Mean consumption across AHEI‐2010 quintiles demonstrated different (P<0.05) amounts of nuts and legumes, vegetables, and polyunsaturated fatty acids.ConclusionsPublic health messages targeted at vegetarians and others who may choose to eat meat‐free on certain days should emphasize decreased consumption of empty calories, and increased consumption of whole grains, plant proteins, nuts and legumes, and vegetables as a way to improve overall dietary quality.Support or Funding InformationUSDA 3062‐51000–51‐00D
The Role of Scleraxis in Intestinal Fibroblasts
Authors: Johnson Charles , Nillas Andrea , Reaves Titus A. 
Published: June 2021

Scleraxis is a transcription factor in the BHLH family originally shown to regulate the development of embryonic tissue into tendon and bone—suggesting a link to collagen production and release. Recently, scleraxis has been shown to play a role in the development cardiac fibrosis. Organ fibrosis typically follows inflammation and involves over activation of myofibroblasts (activated fibroblasts that express α‐smooth muscle actin). Intestinal fibrosis is a somewhat common complication of Inflammatory Bowel Disease (IBD), which primarily includes Crohn's Disease (CD) and Ulcerative Colitis (UC). Intestinal fibrosis is characterized by dysregulated and excessive production of collagen from fibroblasts that results in excessive contraction in the intestine, intestinal stricture and bowel obstruction. Interestingly, approximately 20–25% of IBD patients will develop fibrosis. We hypothesize that scleraxis is expressed by intestinal fibroblasts and can modify the activation of such fibroblasts. Transfection (siRNA) studies show that when scleraxis is reduced in fibroblasts there is an increase in intestinal fibroblast attachment to fibrinogen (CD11b ligand). While exposure of fibroblasts to cytokines does not appear to regulate its expression, scleraxis expression is increased in IBD intestines. Immuno‐purification studies reveal that scleraxis may have a physical link to CD11b suggesting that they may have similar signaling pathways. These results highlight scleraxis as a target molecule in the treatment of diseases involving the over‐activation of fibroblasts.Support or Funding Information5T35DK007431‐32 and and National Science Foundation RII
GPCRs in Pulmonary Arterial Smooth Muscle Cells as Novel Targets in Pulmonary Arterial Hypertension
Authors: Gorr Matthew W , Sriram Krishna , Insel Paul A 
Published: June 2021

Pulmonary arterial hypertension (PAH) is a progressive disease that can eventually result in right heart failure and premature death. The pulmonary arterial tree in PAH narrows and limits the blood supply to the lungs, due predominately to the hyperproliferation and hyperconstriction of pulmonary artery smooth muscle cells (PASMCs). Current therapies for PAH have limited long‐term benefits (in particular, on mortality) and multiple side‐effects, including systemic hypotension. Thus, new means to target PASMCs has the potential to improve therapy for PAH. To this end, we have assessed mRNA expression of G‐protein coupled receptors (GPCRs) using Taq‐man GPCR arrays and RNA‐seq from PASMCs acquired from patients (n=4) with PAH and healthy control subjects (n=4). GPCR array analysis revealed that 91 GPCRs were expressed on average across all samples with most them shared amongst replicates (82 in control and 76 in PAH samples). Thirty‐one GPCRs, including 13 orphan GPCRs (without known physiologic agonists) were highly expressed (average delta cycle threshold < 20) across all samples. In PAH‐PASMCs, 27 and 40 GPCRs were >2‐fold more highly or lower expressed, respectively, than in control‐PASMCs. RNA‐seq analysis confirmed these results. Initial studies indicate enhanced functional activity (proliferation and signaling) of at least one of the more highly expressed GPCRs. Together, these results suggest that newly recognized, more highly expressed GPCRs in PAH‐PASMCs are potential therapeutic targets for this disease. Although further work is needed to validate such GPCRs, we propose that the use of unbiased strategies to identify GPCRs in PASMCs can provide a novel way to discover potential drivers of pathophysiology and therapeutic targets for PAH and other diseases.Support or Funding InformationSupported by Department of Defense (W81XWH‐14‐1‐0372) and the National Institutes of Health (5T32HL007444‐33)