bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deficiency of AMP‐Activated Protein Kinase Alpha 1 Promotes the Vulnerability of Atherosclerotic Plaques at Brachiocephalic Arteries
Authors: DING YE , Zhang Miao , Song Ping , Zou Ming‐hui 
Published: November 2023

BackgroundAtherosclerotic plaque rupture is the most important mechanism responsible for the sudden and unpredictable onset of acute coronary syndromes. We had previously demonstrated that genetic deletion of AMP‐activated protein kinase (AMPK), a master sensor and regulator of energy and redox homeostasis, instigates endothelial dysfunction and accelerates atherosclerosis in mice in vivo. In addition, we have reported that genetically inactivate AMPKα2 in Vascular Smooth Muscle Cells (VSMC) aggravates atherosclerotic plaque instability. However, the roles of AMPKα1, another essential isoform of AMPKα, with respect to atherosclerotic plaque stability remains unclear.ObjectiveThe aim of this study was to evaluate the specific impact of AMPKα1 on atherosclerotic plaque stability in the brachiocephalic arteries (advanced atherosclerosis), and to elucidate the underlying mechanisms.Methods and ResultsAtherosclerotic plaque stability were monitored in the brachiocephalic arteries isolated from Apoe−/− or Apoe−/−AMPKα1−/− mice fed western diet for 10 weeks. We identified that Apoe−/− AMPKα1−/− mice showed multiple features indicative of unstable atherosclerotic plaque relative to Apoe−/− mice. The plaques located in the brachiocephalic artery of Apoe−/−AMPKα1−/− mice displayed higher incidence of intra‐plaque hemorrhage, the presence of buried fibrous caps, and discontinuity of the fibrous caps compared to those found in Apoe−/− mice. Further, the necrotic core sizes and macrophage contents were significantly increased in Apoe−/−AMPKα1−/− mice relative to those from Apoe−/− mice. Conversely, VSMC contents, fibrous cap thickness and plaque collagen contents, which were widely used as indicators of stable plaque, were markedly decreased in Apoe−/−AMPKα1−/− mice when compared to those in Apoe−/− mice. Importantly, the production and activity of macrophage derived MMP9, which is a critical factor in the rupture of unstable atherosclerotic plaques, were significantly increased in brachiocephalic arteries and aortas from Apoe−/−AMPKα1−/− mice. This result was further confirmed in Bone Marrow Derived Macrophages (BMDM) isolated from AMPKα1 deletion mice. Furthermore, we found that AMPKα1 deficiency promoted VSMC apoptosis both in the plaque and in cultured cells. We identified that AMPKα1 deletion increases expression of pNF‐κB p65 both in BMDM and in VSMCs, suggesting that AMPKα1 deletion activates NF‐κB pathway. NF‐κB inhibition with pharmacological inhibitor or siRNA‐mediated silencing of NF‐κBp65 abolished the increase of MMP9 in macrophage and VSMC apoptosis induced by AMPKα1 deficiency.ConclusionsTaken together, this study demonstrates that AMPKα1 deficiency result in increased activity of macrophage MMP9 and induces VSMC apoptosis, which subsequently promotes atherosclerotic plaque instability in NF‐κB‐dependent manner.
Production of TLRs triggered pro‐inflammatory cytokines through calcium dependent and independent pathways in HaCaT cells
Authors: Kim Eunok , Ha Injin , Kim Kyuseok , Park Dain , Lee Min Young 
Published: November 2023

Keratinocytes can be activated by Propionibacterium acnes (P. acne) and lead to the production of pro‐inflammatory cytokines. P. acnes stimulates the production of pro‐inflammatory cytokines via Toll‐like receptor2 (TLR2) and TLR4. In this study, we examined the effects of P. acne on production of cytokines via TLR2 and TLR4 in the HaCaT cells. First, we compared the calcium release from HaCaT, immortalized keratinocytes and THP‐1 monocytes after stimulation with TLR ligands. Our results show that during inflammatory reaction, TLR2 activation with TLR2 ligand increase intracellular calcium influx but not TLR4 in HaCaT. However activation with both of TLR2 and TLR4 ligands increase intracellular calcium influx in THP‐1 monocytes cells. These data suggest that only TLR2 activation in HaCaT cells induce calcium increase different from THP‐1. Furthermore RT‐PCR analysis revealed that TLR2 stimulation induces expression of the epidermal differentiation marker, Keratin 1. These results demonstrate that TLR2 stimulation by P. acnes induce abnormal keratinization and that TLR2 and TLR4 activation increase production of pro‐inflammatory cytokines (IL‐1a, IL‐1b, IL‐6 and IL‐8) in HaCaT cells. The production of pro‐inflammatory cytokines and chemokines in keratinocytes can recruits macrophage cells into keratinocytes and induces inflammation. In conclusion, these results suggest that production of pro‐inflammatory cytokines by TLR2 and TLR4 in HaCaT cells is induced through TLR2 induced calcium dependent and TLR4 induced calcium independent pathway.Support or Funding InformationThis study was supported by a grant from the Traditional Korean Medicine R&D Project, Ministry of Health & Welfare, Republic of Korea. (HI16C0801)
Biology of the lumbar zygapophyseal joint and its clinical implications
Authors: Cramer Gregory D 
Published: November 2023

This session will begin with a brief review of relevant clinical anatomy (including microscopic anatomy) of the lumbar zygapophyseal (Z, facet) joints. The results of a series of mechanisms‐based, proof of concept, animal and human studies will then be summarized. The studies were designed to investigate a fundamental hypothesis of a beneficial effect of spinal manipulation (SM). Briefly, the hypothesis states that the Z joints, which are known pain generators, become hypomobile for a variety of reasons and that connective tissue adhesions develop in these hypomobile Z joints. SM is hypothesized to gap the Z joint facet surfaces, which re‐establishes normal joint movement by, in part, breaking up or preventing the formation of the joint adhesions. Our previous work identified time dependent Z joint adhesions and degenerative changes following induced spinal hypomobility in a rat model. Important to subsequent studies, such Z joint changes are thought to be accompanied by crepitus (joint sounds). In concurrent research, we assessed healthy human subjects (n=64) and subjects with acute and subacute LBP (n=112). We found that the lumbar Z joints gapped during both side‐posture positioning and during SM, and the joints gapped significantly more during SM (following two weeks of treatment for LBP subjects). We then used accelerometers to assess the vibrations associated with Z joint gapping induced cavitation during SM and side‐posture positioning. We identified the specific lumbar Z joints or sacroiliac joints from which cavitations originated during lumbar SM (n=30) and non‐SM controls (n=10) and found a positive correlation between cavitation and Z joint gapping. More recently we assessed healthy (n=5) and low back pain (LBP, n=5) subjects from 3 different age groups (18–25, 26–45, and 46–65 years) to evaluate Z joint crepitus during full ranges of motion before and after SM. This was done to determine the feasibility of using crepitus as a potential biomarker for Z joint hypomobility. In this pilot study, crepitus prevalence increased with age, was higher in LBP than healthy subjects, and overall decreased following SM. We concluded that crepitus assessment using accelerometers has the potential of being an outcome measure for assessing Z joint function during movement and the effects of LBP treatments (e.g., SM) on Z joint function. The session will conclude with a brief discussion of future research planned to further assess non‐invasive, acoustic measures of Z joint function. When combined with imaging (e.g., US) and measures of pain and function, such acoustic measures could help evaluate the relationships among Z joint degeneration and various treatment methods.Support or Funding InformationNIH/NCCIH grants 1‐3R01 AT000123
Hedgehog Signaling in Cardiac Development and Disease
Authors: Moskowitz Ivan 
Published: November 2023

Congenital Heart Disease (CHD), malformations of the heart present at birth, is the most common class of life‐threatening birth defect. Atrioventricular septal defects (AVSDs) are a common and serious form of CHD in humans, comprising 5–10% of all CHD cases and a greater proportion of those requiring surgical correction. Gaining a mechanistic understanding of atrioventricular septation is an essential goal for improving clinical approaches to structural heart disease. Whereas the canonical view of atrioventricular septation was based on intracardiac events centered at the endocardial cushion, recent work demonstrates that cilia‐required Sonic hedgehog (Shh) signaling in the Second Heart Field, outside of the heart proper, drives atrioventricular septation. We harness our new understanding of atrioventricular septation to address the molecular developmental mechanisms underlying ASVDs in more detail. Hh signaling is transduced by the GLI family of transcription factors (TFs). We have previously described a genetic interaction between the cardiogenic TF TBX5 and GLI TFs in the SHF that promotes atrioventricular septation. These studies suggest that Hh signaling‐dependent GLI TFs and cardiogenic TFs co‐regulate a gene regulatory network critical for the specification of atrial septum progenitors. We will present new data that test predictions of this model.Support or Funding InformationThis work has been supported by grants from the NIH (R01 HL092153 and R01HL124836) and AHA (13EIA14690081)
The Role of Long Non‐Coding RNAs in Nuclear Organization and Disease
Authors: Spector David L. 
Published: November 2023

Genome‐wide analyses have identified approximately 16,000 human long non‐coding RNA (lncRNA) genes representing approximately 27% of annotated human genes. LncRNAs tend to localize to cell nuclei implying roles in gene expression and/or nuclear organization. While the number of currently annotated lncRNA genes is close to the number of protein‐coding genes we know relatively little in regard to the molecular mechanisms by which these RNA molecules exert their functions. I will discuss an interesting mouse (19qA) and human (11q13.1) genomic region that harbors 2 lncRNA genes, Neat1 and Malat1. Evidence will be presented for an architectural role of Neat1 in the establishment and maintenance of a nuclear domain called paraspeckles, and Malat1 in regulating gene expression and RNA splicing in breast cancer progression.Support or Funding InformationD.L.S. is supported by NIGMS 42694 and NCI 5PO1CA013106□Project 3
Context‐specific action of ribosomal antibiotics
Authors: Vazquez‐Laslop Nora , Mankin Alexander 
Published: November 2023

Ribosomes are the makers of all cellular proteins and one of the preferred targets of clinically important antibacterials. Polymerization of amino acids into polypeptides occurs at the peptidyl transferase center (PTC), which resides in the large subunit of the ribosome. The nascent protein is then threaded through the exit tunnel in its way out to the cytoplasm. The classic natural compound chloramphenicol and the synthetic antibiotic linezolid specifically bind to the PTC, hindering accommodation of the aminoacylated tRNA substrate, and thus inhibiting formation of peptide bonds. Antibiotics belonging to the macrolide family, such as the natural erythromycin and the semisynthetic ketolides, partially block the exit tunnel, obstructing the passage of the nascent peptide. The classic models for the action of PTC‐ or exit tunnel‐targeting antibiotics have suggested that inhibition of protein synthesis occurs indiscriminately. However, the ribosome profiling analysis of the global translation of bacteria exposed to the drugs and biochemical experiments in cell free systems have revealed that these compounds stall translation in a context specific manner. The PTC‐ and exit tunnel‐targeting compounds show different specificities but, in both cases, the context is dictated by the sequence of the nascent protein. Our findings demonstrate that the protein residing in the exit tunnel influences the properties of the PTC, including its ability to bind inhibitors of translation. Therefore, the mechanism of action of antibiotics is directly affected by the functional link between the exit tunnel and the catalytic core of the ribosome. Non‐universal inhibition of protein synthesis may also apply to other classes of ribosomal‐targeting drugs. Development of antibiotics with improved antibacterial activity may depend on our understanding of their context specific mode of action.Support or Funding InformationNational Institutes of Health Grant R01GM106386National Institutes of Health Grant AI125518Melinta TherapeuticsCempra Pharmaceuticals
MAPK substrate phosphoproteomics screen identifies GRAB as a novel MKP‐5‐regulated MAPK substrate
Authors: Bennett Anton M. 
Published: November 2023

The mitogen‐activated protein kinases (MAPKs) have been shown to regulate skeletal muscle function. Previously, we showed that MAPK phosphatase‐5 (MKP5) negatively regulates regeneration of skeletal muscle through inhibition of p38 MAPK and c‐Jun N‐terminal kinase (JNK) activities. However, the identity and contribution of MKP5‐dependent MAPK targets in the regulation of skeletal muscle function and regenerative myogenesis has not been established. In order to identify MKP5‐dependent MAPK substrates in skeletal muscle, we performed a global differential phospho‐MAPK substrate screen in regenerating skeletal muscles of wild type and Mkp5−/− mice. The results of this screen identified several MKP5‐dependent MAPK substrates that were differentially phosphorylated during muscle regeneration. We discovered a novel MKP5‐regulated MAPK substrate, called guanine nucleotide exchange factor for Rab3A (GRAB) that was hyper phosphorylated by 8‐fold in skeletal muscles of Mkp5−/− mice as compared with wild type mice. We identified that GRAB serine 169 is a novel site of phosphorylation mediated by JNK. Myoblasts overexpressing a phosphorylation‐defective mutant of GRAB (GRAB‐S169A) did not impair myoblast proliferation but inhibited the ability of C2C12 myoblasts to differentiate. We found that GRAB phosphorylation at Ser169 was required for the secretion of the pro‐myogenic cytokine interleukin 6 (IL‐6). Consistent with this observation, MKP5‐deficient mice exhibited increased circulating expression of IL‐6 as compared with wild type mice. Collectively, these data demonstrate a novel mechanism whereby MKP5‐mediated regulation of MAPK activity negatively regulates phosphorylation of GRAB which in turn is responsible for the secretion of the pro‐myogenic cytokine, IL‐6. These data are consistent with the notion that MKP5 serves as an essential regulator of MAPK‐dependent signaling in skeletal muscle.Support or Funding InformationNIH/NIAMS RO1 AR066601
Genetic analysis of pathogenesis in Toxoplasma gondii
Authors: Sibley L. David 
Published: November 2023

Toxoplasma gondii is a widespread parasite of animals that also causes opportunistic infections in humans. Forward genetic mapping studies and comparative genomic analyses of diverse strains have collectively demonstrated that virulence is largely mediated by expansion of several families of secretory pathogenesis determinants (SPDs). Among these are secreted effectors that bind to host transcription factors to disrupt host gene expression. For example, the recently described Inhibitor of STAT1 Transcription (TgIST) blocks the effect of interferon gamma, which is normally mediated by this host transcription factor. TgIST is secreted across the parasitophorous vacuole by a parasite‐encoded export pathway on the vacuole membrane. Within the host cell, TgIST binds to active phosphorylated STAT1 homodimers that are found tightly bound to promoter elements in nucleus, yet paradoxically transcription is blocked. Biochemical studies revealed that TgIST works by recruiting the Nucleosome Remodeling and Repressive complex (NuRD), which modifies chromatin to suppress gene expression. TgIST is predicted to be a highly unstructured protein, suggesting it recognizes its binding partners through induced fit – a property shared by many transcriptional co‐factors. TgIST is conserved among all strains of T. gondii and it mediates repression of type I, II and III interferons, thus dampening immunity. These studies reveal the molecular mechanism of how SPDs mediate changes in host gene expression to block innate immunity and contribute to pathogenesis.Support or Funding InformationSupported by grants from the NIH.
Metabolic and transcriptional alterations observed in the early stages of cardiac substrate switching hint at novel mTOR‐regulated hypertrophy signaling pathways
Authors: Pascual Florencia , Schisler Jonathan C. , Grevengoed Trisha J. , Coleman Rosalind A. 
Published: November 2023

Cardiomyocyte‐specific deficiency of long‐chain acyl‐CoA synthetase 1 (Acsl1H−/−) results in a block in FA oxidation, rendering the heart dependent on the oxidation of glucose for contractile energy. Ten weeks after temporally‐induced Acsl1 inactivation, knockout hearts exhibit a 90% reduction in total ACSL activity and FA oxidation, and a compensatory increase in glucose uptake, as well as the development of mTOR‐mediated hypertrophy and diastolic dysfunction. Concomitant treatment with the mTOR inhibitor rapamycin for 10 weeks prevents cardiac hypertrophy due to the attenuation in the abnormal expression of hypertrophy‐associated genes as well as a block in ventricular S6K phosphorylation, suggesting heart‐specific mTOR signaling. The current work examines the early changes in gene expression, metabolites, and cardiac function as the Acsl1‐deficient heart adapts to the loss of FA substrate. Two weeks after cardiac‐specific Acsl1 ablation, ACSL activity decreased 60% and glucose and FA uptake were markedly altered, consistent with a shift toward glycolytic oxidation. Strikingly, this partial inhibition of FA activation was sufficient to elicit cardiac hypertrophy, the development of which was reversed by concomitant rapamycin treatment. No significant changes were observed in plasma glucose, NEFA, free glycerol or TAG, indicating that systemic metabolic homeostasis was not affected by short‐term cardiac Acsl1 deficiency. However, rapamycin‐responsive changes to the metabolic fingerprint and transcriptional response of Acsl1H−/− hearts were observed, many of which were unique to the two week time point. Notably, alterations in the rapamycin‐sensitive mTOR genes identified in the ten week cardiac Acsl1 inactivation model were not evident at two weeks, despite the observed development of cardiac hypertrophy in both temporal knockout models. In addition, changes in expression of fibrosis genes were detected only in the short‐term Acsl1 abrogation model. Taken as a whole, these results support the notion that cardiac hypertrophy can develop via a novel pathway. Additional analyses of microarray and metabolomic data, as well as histological studies of fibrosis and hypertrophy, will allow us to elucidate the interrelationship between hypertrophy, cardiac dysfunction, and substrate use in heart.Support or Funding InformationSupported by DK59935 and a grant from the American Heart Association 12GRNT12030144.
Diet Quality Declines and Differs by Race in Early Childhood
Authors: Reynolds Kelly Anne , Kalkwarf Heidi , Summer Suzanne , Khoury Phil , Gavin Marcia , Woo Jessica G 
Published: November 2023

IntroductionDiet quality is an important determinant of health in children, but little is known about how diet quality progresses during early childhood. We hypothesized that overall diet quality, assessed by the 2010 Healthy Eating Index, would decline during early childhood.MethodsThree hundred seventy‐two (372) healthy 3‐year‐old children were recruited from the Greater Cincinnati area and assessed every 4 months until age 7 at in‐person clinical visits, for a total of 13 visits. Parents completed 3‐day diet diaries at each visit which were analyzed for nutrient composition using the Nutrition Data Systems for Research system (NDSR). The 2010 Healthy Eating Index (HEI) total and food‐group component scores were calculated and averaged by year of study. Longitudinal mixed modeling was used to evaluate longitudinal trends.ResultsThe population was 52% (195/372) male, 78% (290/372) white and 83% (308/372) completed the final visit. HEI total scores at age 3 were poor (mean±SE: 45.2±0.4) and declined significantly between ages 3–7 (p<0.0001). None of the participants had “good” quality diet (HEI>80) at any point in the study. HEI total scores differed by race, with white children having significantly higher scores (p=0.05, Figure 1). HEI component scores showed a mixed pattern, with some significantly improving (protein [Figure 2], vegetables and fatty acids), some significantly worsening (dairy, refined grains, sodium, whole fruit and total fruit); other component scores did not change. Differences by race also varied, with African‐Americans having consistently better scores for vegetables, greens and beans, protein and fatty acids (all p<0.0001, Figure 2), while white children had better scores for dairy, sodium and refined grains (all p<0.0005).ConclusionsThe average HEI scores for young children showed poor baseline diet quality at age 3 that became gradually worse throughout early childhood. The varying patterns in HEI component scores indicate specific areas of focus for early dietary intervention, which may differ by race.
Macronutrient composition of early childhood diet is associated with growth and adiposity
Authors: Voortman Trudy , Braun Kim V.E. , Jaddoe Vincent W.V. , Franco Oscar H. 
Published: November 2023

BackgroundPrevious studies suggest that high protein intake in infancy leads to a higher body mass index. However, it is not clear whether lean or fat mass are affected and what the role is of the other macronutrients in the diet. We examined associations of macronutrient composition of the diet in early childhood with growth and detailed measures of body composition up to the age of 9 years.MethodsThis study was performed among 3,564 children participating in a population‐based cohort study in the Netherlands. Dietary intake was assessed with food‐frequency questionnaires at age 1 year. We calculated intakes of total protein and protein from different sources; of total carbohydrates, fiber, polysaccharides, monosaccharides and disaccharides; and of total, saturated, monounsaturated and polyunsaturated fat. Height and weight were repeatedly measured between the ages of 1 and 9 years. Fat and fat‐free mass were measured at 6 and 9 years using dual X‐ray absorptiometry. We calculated age‐ and sex‐specific SD scores for height, weight, body mass index (BMI), fat‐mass index (FMI), and fat‐free mass index (FFMI). Macronutrient intakes were expressed in energy percentages and entered in multivariable linear mixed models in which we examined different macronutrient replacement effects. Models were adjusted for maternal age, education, BMI, and smoking and for child's sex, age, ethnicity, birth weight, having received breastfeeding, diet quality, television watching, and playing sports.ResultsMean (±SD) macronutrient intakes were 12.9 (±2.4) E% from protein, 28.6 (±5.6) E% from fat, and 58.4 (±5.9) E% from carbohydrates. Results from multivariable models showed that higher intake of total and animal protein (both dairy and non‐dairy) was associated with a higher height, weight and BMI up to the age of 9 years, irrespective of whether it was replacing carbohydrates or fats in the diet. Further analyses showed that the positive association with BMI was completely explained by a higher FMI, and not by FFMI. In multivariable models, no significant associations were observed for any of the other macronutrients.ConclusionsOur results suggest that high protein intake, particularly animal protein, in early childhood is associated with a higher body fat mass, but not fat‐free mass. Future studies are needed to examine the optimal range of protein intake and macronutrient composition of the diet for infants and young children.