bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cortical and trabecular bone density distribution in primate and felid limb epiphyses
Authors: Perry Taylor A , Chirchir Habiba 
Published: June 2021

Studies show that cortical and trabecular bone are responsive to mechanical loading, albeit in different ways. Increased loading results in an increase in trabecular bone density in epiphyses, whereas articular cortical bone is conserved to maintain joint congruity. However, the co‐distribution of articular cortical and trabecular bone density in joints has not been reported within a mechanical loading context, and in reference to locomotor behavior. This study analyzes cortical and trabecular bone density co‐distribution based on habitual loading in multiple limb elements across taxa with different locomotor behaviors (bipeds, terrestrial quadrupeds and arboreal quadrupeds). We predict that joints subjected to greater loading during locomotion will have an increased ratio of trabecular bone density to cortical bone than those that experience reduced loading. Specifically, we predict that non‐primate quadrupeds known to experience greater substrate reaction forces on the forelimb than hindlimb will exhibit greater trabecular to cortical bone density ratio in the forelimb epiphyses than the primate quadrupeds. We test this prediction using peripheral quantitative computed tomography (pQCT) measuring trabecular and cortical bone density in primates and felids. Results from one‐way ANOVA with Tukey post‐hoc corrections show that the femoral head in all locomotor groups studied display the least ratio between trabecular and cortical bone density in comparison to other limb elements. Additionally, other elements did not follow predicted patterns of bone density distribution based on locomotor behavior. Instead, they vary according to phylogeny. The results indicate that the femoral head, a relatively large epiphyseal element, displays greater density ‐ both cortical and trabecular ‐ regardless of locomotor repertoire. This suggests there are potentially non‐loading factors influencing observed bone distribution patterns. Furthermore, this study correlates bone density, fracture susceptibility, and injury risk, which have significant clinical applications.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Nondestructive Measurement of Regenerated Esophageal Biaxial Mechanical Properties Utilizing Sonometry For Determination of Directional Esophageal Regeneration
Authors: Aho Johnathon M , Barron Matthew R , Qiang Bo M , Wigle Dennis A , Tschumperlin Daniel M , Urban Matthew W 
Published: June 2021

Esophageal diseases often necessitate resection of tissue. Current reconstruction options using autologous conduits such as stomach, colon, and small bowel have significant morbidity. Given these limitations in current therapy, we have developed a large animal model to regenerate short segments of esophageal tissue after circumferential full thickness resection. This is performed by implantation of an electrospun polyurethane tissue engineered graft which results in esophageal regrowth. These implantations have been performed both with cell based seeding the polymer scaffold and without with comparable regenerative results. It is possible that esophageal regeneration in this model has unequal contributions from either the proximal or distal esophagus. To determine preferential directionality of regeneration we aim to utilize biomechanical markers to suggest that there are unequal proximal and distal contributions to regenerated tissue. Given limited availability of regenerated tissue, use of a non‐destructive method to perform this testing would have significant utility. Through using our previously validated non‐destructive sonometric ex vivo method we aim to determine differences in mechanical behavior of the regenerated tissue in comparison to proximal and distal esophageal tissues. Using this method we are able to determine longitudinal and circumferential moduli and derive strain energy functions and parameters. Within this work we demonstrate that there are differences in mechanical behavior and that the regenerated tissue behaves more comparably to proximal esophageal tissue suggesting preferential regrowth and unequal contribution to regenerated tissue.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mitochondrial Impairment Upregulates MICOS Expression in a Human Microglial Cell Model
Authors: Carot Alejandra Bargues , Malovic Emir , Jin Huajun , Anantharam Vellareddy , Kanthasamy Arthi , Kanthasamy Anumantha 
Published: June 2021

Mitochondrial dysfunction and oxidative stress have been implicated as key pathological mechanisms underlying the dopaminergic neurodegenerative process of Parkinson's disease. The mitochondrial contact site and cristae‐organizing system (MICOS) complex, formed by two subcomplexes with a total of 7 subunits, is associated with the formation and maintenance of mitochondrial cristae structure and respiratory complexes as well as in the regulation of mitochondrial import machinery. Alterations of MICOS subunit protein levels, mutations, and protein modifications have been associated with distinct human diseases, including Parkinson's disease, diabetic cardiomyopathy, epilepsy, and cancer. Previous studies using the classic mitochondrial complex‐1 inhibitor rotenone have shown that overexpression of Mic60 attenuates the rotenone‐induced cell death and increased mitochondrial respiration and spare respiratory capacity in PC12 and SH‐SY5Y dopaminergic cell models. We recently reported that mitochondrial impairment in microglia amplifies the neuroinflammatory response in cell and animal models of rotenone‐induced neurotoxicity. To further understand the cellular mechanism underlying mitochondrial impairment and neuroinflammation, we investigated the effect of rotenone on MICOS subunits, specifically Mic27 and Mic60, in the novel C20 human microglia cell model. Our immunocytochemical, qPCR and Western blot analyses revealed that exposing C20 cells to rotenone for 24 hours induced the upregulation of Mic27 and Mic60. Microglia are known to be extremely resilient cells whose metabolic states differ greatly in comparison to neurons. Therefore, our future studies will determine if the upregulation of MICOS subunits in microglia represents a compensatory mechanism to relieve mitochondrial stress.Support or Funding Information(NIH grants NS100090, NS088206 and ES027245)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Investigating the Kinetic Effects of the Allosteric Interaction Between Newly‐Discovered Dynamic Hydrogen‐Bonded Residues and the HINT1 Active Site
Authors: Wang David , Strom Alexander , Wagner Carston R. 
Published: June 2021

Histidine Triad Nucleotide binding proteins (HINTs) are an ancient class of enzyme notable for their acyl‐AMP hydrolase and phosphoramidase activity. This class of protein is of research significance due to its involvement in antiviral prodrug activation, as well as its natural role in opioid tolerance. Previously, the Wagner Lab has published the substrate specificity profile, full kinetic mechanism, and kinetics assay for the HINT isozyme HINT1. However, the active site dynamics of this enzyme have yet to be elucidated.Recent insights into the structural dynamics of HINT enzymes found via CPMG‐NMR and discovered by the Wagner Lab have revealed a potential site of regulation for the kinetic rates of HINT1. We hypothesize that a subtle allosteric interaction exists between the active site of HINT1 and the previously unrecognized distant site through a channel of conserved waters, which plays a key role in the active site dynamics and kinetics.Thus, with the goal of investigating the kinetic properties of this potential allosteric interaction, two genetic mutants of the enzyme HINT1 were produced to eliminate or alter the interactions between the highly dynamic residues Q62 and E100. Both steady‐state and stopped flow pre‐steady state kinetic analyses were performed on the mutants to determine any significant changes to their kinetics. Furthermore, circular dichroism analysis of both mutants was performed to ensure that both mutants were structurally sound, with no significant enzyme misfolding.Through these analyses, it was found that the kcat and Km of the HINT1 mutants were altered significantly and predictably through the pair of successive mutations. Through process of elimination, these findings informed us that these mutations to the dynamic residue Q62 must be altering the rate of intermediate hydrolysis at the HINT1 active site, a site previously thought unlikely to be altered.Support or Funding InformationPartial funding of this study by the University of Minnesota Office of Undergraduate Research is gratefully acknowledged.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Identifying an Allosteric Switch Region in Human SIRT1
Authors: Huynh Angelina , Amaya Carina Araceli , Montermoso Saira , Lustig Brooke , Wang Ningkun 
Published: June 2021

SIRT1 is an NAD+‐dependent lysine deacetylase that is implicated in age‐related diseases and is a potential therapeutic target for drug development. The N‐terminal domain is highly disordered and is usually removed prior to crystallization of the enzyme. However, it has been known to physically interact with the catalytic core to increase enzyme activity. The mechanism of this remains unknown. STAC binding domain (SBD), within the N‐terminal region, is the binding site for sirtuin‐activating compounds (STACs) such as resveratrol, which is known to enhance SIRT1 activity towards peptide substrates including p53W. An allosteric switch is hypothesized as a single or multiple residues responsible for a change in secondary structure essential for allosteric activity and mostly found in disordered regions. Detailed information on switch regions remains unexplored due to the challenges of crystallizing the disordered regions. Our project aims to identify and confirm an allosteric switch region within the N‐terminal domain of SIRT1. The first aim is to computationally identify a switch region in SIRT1 using sequence‐and homology‐based descriptors. A possible switch region is hypothesized as having (1) high secondary structure variability, (2) low sequence entropy, and (3) low sequence disorder propensity, inferred by a combination of predictors. Applying these predictors to the full sequence of SIRT1 showed that such a switch may occur within residues 186–193 (TFVQQHLM) of the SBD. The second aim is to experimentally confirm these predictions. We have mutated the predicted region to serine residues: 186–189S, 190–193S, 188S, and 192S. The enzyme kinetics of the mutants remain relatively similar to the wild‐type SIRT1. We then tested these mutants for susceptibility to allosteric modulations by assaying their enzyme activity towards p53W with and without resveratrol. No increase in activity with the addition of resveratrol would confirm that these residues are involved in an allosteric switch. These results will inform the accuracy of the computational descriptors and provide a better understanding of the regulation of this enzyme in the cellular system.Support or Funding InformationCalifornia State University Program for Education and Research in Biotechnology; Louis Stokes Alliance for Minority ParticipationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A Securinine Derivative as a Novel Treatment for Acute Myeloid Leukemia
Authors: Oldford Natasha R. , Karunanithi Sheela , Liu Ruifu , Hou Youngchun , Stetson Lindsay , Roe Anne , Lee Grace , Goyco Juan Valentin , Moreton Stephen , Wald David 
Published: June 2021

Acute Myeloid Leukemia (AML) is a rapidly developing cancer of the bone marrow, with a five‐year survival rate of 27.4%. Current methods of treatment are toxic to older patients, creating a need for new treatment options that are more optimal for patient's health. One potential new treatment is with securinine, a natural compound from the Securinega suffruticosa plant that inhibits AML cell growth. Novel securinine derivatives were tested through cell viability assays, and compound 250 was found to exhibit anti‐cancer properties at a higher potency and lower toxicity than the parent drug. 250 was tested in in vivo AML models that exhibited a decrease in the AML burden on the mouse. Further experiments showed that 250 was able to inhibit thioredoxin reductase, an enzyme which maintains redox homeostasis within the cell. This resulted in negatively affecting AML cell metabolism. Nicotinamide add back experiments with 250 treatment allowed the cells to overcome the cytoxicity and decreased the cell death compared to 250 alone. When analyzing various cancers, it was found that AML cell lines had much lower amounts of Thioredoxin reductase compared to solid cancer lines, leading to 250's potent effect on AML cell lines. Future studies may focus on the effect of 250 on p‐38 activation, and p‐38's relevance in 250 mediated AML cell death.Support or Funding InformationThe research was supported by the NIH grant R43CA22870.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mice lacking membrane‐localized estrogen receptor 1 (mESR1) are partially protected from reproductive pathologies resulting from developmental diethylstilbestrol (DES) exposure
Authors: Ortega Madison Taylor , Cooke Paul S. , Medrano Theresa I. , Mesa Ana M. , Nanjappa Manjunatha K. , Caldo Paul D. , Mao Jiude , Kinkade Jessica A. , Levin Ellis R. , Rosenfeld Cheryl S. 
Published: June 2021

Both membrane and nuclear fractions of estrogen receptor 1 (ESR1) mediate 17β‐estradiol (E2) actions. Mice expressing nuclear (n)ESR1 but lacking membrane (m)ESR1 (nuclear‐only estrogen receptor 1 [NOER] mice) show reduced E2 responsivity and reproductive abnormalities culminating in adult male and female infertility. Using this model, we investigated whether reproductive abnormalities caused by the synthetic estrogen diethylstilbestrol (DES) are mitigated by mESR1 ablation. To test this, homozygous and heterozygous wild‐type (WT and HET, respectively) male and female mice and NOER mice were subcutaneously injected with DES (1 mg/g BW) or vehicle daily from postnatal day (PND) 1–5. Uterine histology was assessed in select DES‐treated femalesa at PND 5, whereas others were ovariectomized at PND 60 and treated with E2 (10 ng/g BW) or vehicle 2 weeks later. In WT females, DES resulted in ovary‐independentepithelial proliferation in the vagina and uterus. These changes were absent in DES‐treated NOER females. Uterine gene expression paralleled cell proliferation differences with neonatal DES inducing ovary‐independent adult expression of classical E2‐induced transcripts (e.g., Lf, Ezh2) in WT but not NOER mice. Males were examined around PND 90. DES‐treated WT and heterozygous males showed smaller testes and increased incidence of bacterial pyogranulomatous inflammation encompassing the testes, epididymis and in some cases the ductus deferens with spread to lumbar lymph nodes; such changes were largely absent in NOER males. Results indicate male and female NOER mice are protected from deleterious effects of neonatal DES and thus, mESR1 signaling is required for adult manifestation of DES‐induced reproductive pathologies.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Multiple Persistent Environmental Chemicals at Low Concentrations Differentially Regulates Fatty Acids/Lipids in Wild Type and PPARAa−/− Mice
Authors: Gonnabathula Pavani K , Yakubu Momoh A 
Published: June 2021

Many chemicals are detected in the environment at very low levels, they were viewed as being incapable of causing harm. Their risks to human health and associated environment are now emerging. But effects of their multiple interactions at cellular and molecular levels is unknown. We have investigated the effects of treatment of wild type and PPARα knockout mice on fatty acid contents in different organs. Mice were treated with low concentrations of multiple persistent environmental chemicals: atrazine, dieldrin, endrin, endosulfan and anthracene (1–100ng/L) in drinking water for six weeks and brain, liver, kidney, heart and spleen were collected, processed for fatty acid/lipid contents determination by GC/MS. The percentage changes in the levels of the fatty acid following treatment were calculated for wild type (WT) and PPARα −/− (KO). The changes (WT and KO) were compared to find the effects of treatment and the genetic (PPARα) influence on the regulation of fatty acid levels. Our results show differential presence of fatty acids: hexadecanoic acid, hexadecanoic acid methyl ester, hexadecanamide, 9‐octadecanemaide, pentadecanoic acid, octadecanoid acid, arachidonic acid, and cholesterol in the different organs as well as their differential regulation in the WT and KO. Results are summarized in Tables 1 and 2. Briefly, treatment increased 9‐octadecanemaide by 145% (WT) and 38% (KO) in the heart, reduced in the kidney 17% (WT), 29% (KO); hexadecanoic acid, octadecanoic acid was increased 0% (WT) but by 178% and 110% respectively (KO) (kidney), octadecanoic acid went up by 334% (KO) with not change in WT, hexadecanamide increased by 92% in KO Liver with 5% in WT. Generally, more perturbations in the regulation of the levels of fatty acid species in the KO than in the WT. These results indicate that multiple persistent environmental chemicals at low concentrations have limited effects on fatty acid dynamics in the WT but enhanced possible dysregulations in the PPARAα−/− mice.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
PKCα Mediates mTORC1 Activation in Non‐Small Cell Lung Carcinoma Cells with EGFR Deletion Mutation
Authors: Salama Mohamed Fouda , Liu Mengling , Clarke Christopher , Espaillat Mel Pilar , Haley John , Obeid Lina , Hannun Yusuf 
Published: June 2021

Constitutively active epidermal growth factor receptor (EGFR) mutations play critical roles in the development and progression of non‐small cell lung cancer (NSCLC). Patients with EGFR mutations are initially sensitive to EGFR‐tyrosine kinase inhibitors; however, they eventually develop drug resistance. Therefore, thorough understanding of mutant EGFR signaling is crucial in order to avoid such resistance and develop novel control therapeutic strategies. In the present study, we observed high PKCα expression in lung adenocarcinomas and in NSCLC cells with EGFR exon 19 deletion mutation. Next, we examined the role of the highly expressed PKCα in the signaling pathways downstream of mutant EGFR. Our results demonstrated that targeting PKCα either by pharmacological inhibition or downregulation impaired mTORC1 signaling, decreased proliferation, and induced caspase‐3 dependent apoptosis in cells with EGFR mutation. Moreover, PKCα gain of function was sufficient to induce proliferation of cells with wild‐type EGFR when grown under low serum conditions that was further increased when co‐expressed with mutant EGFR. Our results clearly demonstrate important roles of PKCα in regulating mTORC1 activity in NSCLC cells with mutant EGFR, whereby a switch occurs from a PKCα‐independent to a PKCα‐dependent signaling. The results suggest that PKCα could be synergistically targeted for the treatment of NSCLC with constitutively active mutant EGFR.Support or Funding Information1. This work was supported by NCI grant CA97132This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Annexin V and gaussia luciferase fusion protein studies for bioluminescence apoptosis detection
Authors: Perez Andres 
Published: June 2021

Programmed cellular death, otherwise known as apoptosis, is a hallmark of many prominent diseases ranging from cancerous to neurodegenerative. Due to this common cellular fate found in a variety of diseases, it has become a goal to develop and construct a mechanism through which apoptotic cells can be detected with a high selectivity. Herein, we describe the development of a class of biosensors are capable of identifying these cells destined for apoptosis through the use of Annexin V alongside a bioluminescent reporter expressed as a single fusion protein. In this work, the bioluminescent protein used is Gaussia luciferase (GLuc), natively expressed by the copepod Gaussia princeps. Annexin V is a protein innately found in the human body that will bind to phosphatidylserine (PS), a membrane phospholipid that shifts towards the outer membrane when the cell has become apoptotic, a key marker of regulated cell death. By combining Annexin V with Gaussia luciferase, we developed a a fusion protein (AgFP), and demonstrated it to be stable, show correlating results when testing for bioluminescence. Analyses through in vitro studies show the potency that the fusion protein, AgFP, does not inhibit either component of the construct from either binding PS or generating bioluminescent signals. Future prognosis of this Annexin‐Gaussia fusion protein includes testing using in vivo models with certain pathologies and determining whether bioluminescence is seen in the target area at a level of affinity and selectivity that can be statistically significant in detecting apoptosis. End stage applications of the fusion protein construct would be an effective and reliable way to screen various areas of the human body for abnormal rates of apoptosis and possibly intervene before some of these lethal diseases become too advanced.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.