bluuebunny/crossref_metadata_2025_split huggingface dataset:
Promyelocytic Leukemia Tumor Suppressor Factor (PML) as a Biochemical Signal for Integration of Synaptic Plasticity
Authors: Tejada‐Simon Maria Victoria , Butler Karlis , Oni Emmanuel 
Published: June 2021

The promyelocytic leukemia protein (PML) is a tumor suppressor factor associated with acute promyelocytic leukemia. It is involved in very important cellular processes. Recent studies suggest that PML also exerts some functions outside of the haemopoietic cells. In the brain, PML expression was found to be restricted to the neural progenitor cells of the developing neocortex, and protein ablation caused an impairment of cell differentiation and a decrease in cortical thickness, indicating that PML might be important for neurogenesis. It is well established that neural progenitor cells are also present in the hippocampus, and that hippocampal neurogenesis is required for hippocampus‐dependent learning. Thus, we hypothesize that lack of PML in the developing brain will likely lead to neurodevelopmental defects that impair neuronal plasticity and function in the adult animal affecting cognition. To test this hypothesis we examined the effect of PML ablation on 1) protein expression levels, 2) behavior, and 3) neuronal cytoarchitecture. Studying the expression of different proteins involved in synaptic plasticity and neurogenesis (Rac, Cdc42, ERK, PI3K, AKT, and mTOR) will provide a better understanding on the role of PML in the brain and how it regulates neurogenesis within the cortex and hippocampus, affecting neuronal structure and function. Additionally, performance on certain learning tasks will suggest whether PML might be relevant for cognition and mental health. Taken together, our findings point to PML as having an important role in brain function.Funding by NIH‐NS048037, UH‐I098045 (M.V.T.S.).
IGFBP‐2 Expression in MCF‐7 Cells is Regulated by the PI3K/AKT/mTOR Pathway through Sp1 Induced Increase in Transcription
Authors: Mireuta Matei , Darnel Andrew , Pollak Michael 
Published: June 2021

Insulin‐like growth factor binding protein 2 (IGFBP‐2) has been implicated in the pathophysiology of neoplasia. The PI3K/AKT/mTOR pathway has recently been implicated as a predominant regulator of IGFBP‐2 at the protein level in MCF‐7 breast cancer cells.ObjectiveTo elucidate the specific molecular mechanisms that underlie this regulation.ResultsWe show that the PI3K/AKT/mTOR pathway regulates IGFBP‐2 protein levels by modulating IGFBP‐2 mRNA abundance in MCF‐7 cells. This change is achieved by regulating transcription through a critical region present in the first 200 bp upstream of the transcription initiation site where Sp1 transcription factor binds and drives transcription. Manipulations of the PI3K/AKT/mTOR pathway lead to changes in posttranslational modifications and nuclear abundance of Sp1 transcription factor.Methods usedQRT‐PCR, ELISA, Western Blot, Luciferase reporter assays, Immunofluorescence, Chromatin immunoprecipitation.ConclusionThis work provides a mechanistic explanation for the observed effects of the PI3K/AKT/mTOR pathway on IGFBP‐2 levels in MCF‐7 cells.Matei Mireuta was supported by the graduate studentship from the Weekend to End Breast Cancer of the Jewish General Hospital Foundation.
Does cerebral blood flow & oxygenation limit maximal exercise performance in healthy humans?
Authors: Louvaris Zafeiris , VOGIATZIS IOANNIS , DIMITRIS ATHANASOPOULOS , VASILIS ANDRIANOPOULOS , PANAGIOTIS ALEXOPOULOS , HARRIETH WAGNER , HABAZETTL HELMUT , ROUSSOS CHARIS , WAGNER PETER , ZAKYNTHINOS SPYROS 
Published: June 2021

Recent reports suggest that changes in cerebral oxygenation may play a pivotal role in limiting maximal exercise capacity in humans.We investigated whether a critical change in cerebral oxygen blood flow and oxygenation may occur from modest to supra‐maximal exercise in hypoxia compared to normoxia.Cerebral blood perfusion was measured by near infrared spectroscopy using indocyanine green dye in 11 cyclists during an incremental discontinuous protocol to the limit of tolerance.During both normoxic and hypoxic (FIO2: 0.12) conditions brain blood flow significantly increased reaching identical levels, at maximal (42±5 versus 42±2 ml/min/100g) and supra‐maximal (40±5 versus 40±4 ml/min/100g) exercise. Deoxy‐hemoglobin concentration (deoxy‐Hb: an index of oxygen extraction) was greater in hypoxia compared to normoxia at maximal (13.1±1.3 vs. 2.3±0.5 μmol/L) and supra‐maximal (11.9±1.5 vs. 2.5±0.5 μmol/L) exercise. Neither in hypoxia nor in normoxia deoxy‐Hb changed significantly from modest (60% max) to supra‐maximal exercise (13.8±1.6 vs. 11.9±1.5 and 1.0±1.5 versus 2.5±0.5 μmol/L, respectively). Importantly, supra‐maximal normoxic deoxy‐Hb (2.5±0.5 μmol/L) was lower than that recorded at 60% max exercise (13.8±1.6 μmol/L) in hypoxia.Cerebral blood flow and oxygenation do not appear to be the signals that terminate exercise in humans.
Influence of contractile work and muscle fiber recruitment on skeletal muscle blood flow in humans
Authors: Richards Jennifer Clarke , Crecelius Anne R. , Kirby Brett S , Dinenno Frank A. 
Published: June 2021

Contractile work has been considered the primary determinant of skeletal muscle oxygen consumption (VO2), which is tightly coupled with blood flow (BF). Recently it was observed that within matched work conditions, the BF response following a single contraction increased with a greater degree of muscle fiber recruitment (MFR). The purpose of this study was to determine whether the primary determinant of skeletal muscle BF was contractile work or MFR during exercise. Accordingly, we measured the forearm BF response (FBF; Doppler ultrasound) during 4 minutes of rhythmic handgrip exercise (RHE) in 9 young males. Each workload (low and high) consisted of two trials matched for total work by varying the load (% maximal voluntary contraction; %MVC) and the contraction: rest ratio (low: 20%1:7 vs 10%1:3, high: 20%1:3 vs 10%1:1). Greater MFR was attained by increasing %MVC. VO2 was calculated from FBF and deep venous blood samples. Greater MFR significantly increased the FBF response at both low and high workloads (164±16 vs 139±16 p=.03 and 270±24 vs 240±20 p=.01 (ml min−1)). Greater MFR did not significantly affect VO2 (207±19 vs 177±23 p=0.3, and 327±44 vs 305±37 p=0.4(ml min−1)) at any workload, however, the ratio of ΔFBF: ΔVO2 was unchanged. Our preliminary data suggest contractile work is not the primary determinant of FBF and greater MFR may have an independent influence on FBF during RHE in humans.Supported by HL‐087952
Effect of Surface Charge of Silver and Gold Nanoparticles on the Cytotoxicity in Human Lung Carcinoma, A549 Cells
Authors: CHOI SEON YOUNG , PARK JIN HO , JANG SOO HWA , LEE HOSUB , LEE KANGTAEK , RYU PAN DONG , YANG SUNG IK , JOO SANG WOO , LEE SO YEONG 
Published: June 2021

The cytotoxicity of oppositely‐charged gold (Au) and silver (Ag) nanoparticles (NPs) was compared using 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT), lactate dehydrogenase, and fluorescence activated cell sorter (FACS) measurements. NP uptake into the A549 cells was characterized by transmission electron microscopy. According to the MTT viability assay, positively charged NPs were found to be more toxic compared to negatively charged NPs. FACS analysis demonstrated that the cells treated with both Ag and Au NPs possessing positive or negative charges showed an increase in the sub‐G1 phase suggesting that the decrease in cell viability is due to the induction of apoptotic effects in the cells. These results indicate that the surface charge effects of Ag and Au NPs on cytotoxicity is crucial for the potential application of Ag and Au NPs in biological system.This work is supported by National Research Foundation of Korea (2009‐0066580)
Effect of glucose tolerance on muscle atrophy in streptozotocin‐induced diabetic rats
Authors: Park Inhee , Lee Seunghoon , Lee Youngjeon , Hong Yonggeun 
Published: June 2021

Diabetic mellitus (DM) is characterized by an increased plasma glucose level, and reduced glucose uptake can activate protein degradation machinery leading to autophagy in skeletal muscle fibers. Thus, in this study we investigated the effect of glucose tolerance on numerous markers related to muscle atrophy in skeletal muscles obtained from streptozotocin‐induced diabetic rats. Male Sprague‐Dawley rats (n=8, eight‐week‐old) were divided into two experimental groups: diabetic (group‐DM, induced i.p. by streptozotocin at 60 mg/kg) and group‐C (treated with vehicle for eight weeks). The blood glucose level in the rats was determined each week using blood samples obtained by venipuncture of a tail vein. After eight weeks, the rats were sacrificed by decapitation and skeletal muscle tissue was collected for RNA isolation. The differential expression of muscle atrophy‐related genes such as MuRF1 and MAFbx was then analyzed. MuRF1 expression was significantly increased in the skeletal muscles of the diabetic rats. Our results indicate the expression of specific muscle atrophy‐related genes increased in diabetic‐induced muscle atrophy.Funding: BioGreen21 Program (Code No. 20070401‐034‐006‐009‐02‐00), Rural Development Administration, Korea
Evaluation of PI3K expression and its interaction with angiotensin II on central autonomic nuclei of hypertensive animals
Authors: Antunes Vagner Roberto , Buttler Leila 
Published: June 2021

There is evidence that PI3K protein is directly linked to the intracellular signaling of the angiotensin II (ANG II) pathways (via AT1 receptors) that act as a neuromodulator of autonomic outflow in spontaneous hypertensive rats (SHR). In the present study we evaluate the difference on the PI3K expression as well as its interaction with ANGII in the PVN, NTS and RVLM of SHR compared to WKY and wistar rats. Immunoblotting was performed to quantify the regulatory subunit p85 of the PI3K and phosphorilated PKB (active form) in the PVN, NTS and RVLM of SHR and normotensive rats. Moreover, we also evaluated the role of ANG II and its interaction with PI3K at the PVN level in regulating the lumbar sympathetic nerve activity (LSNA) by using an in situ arterially perfused preparation. The expression of p85 subunit did not differ among all nuclei studied at any experimental group, but the phosphorilated PKB was significantly more expressed in the PVN of SHR (1.5x) when compared to wistar and WKY. ANG II (10 μM) microinjected into the PVN elicited an increase in LSNA (18%), which was attenuated at 5 min after LY294002 (50 μM) microinjected into the same site (2%), with recovering 20 min later (17%). If there is any interaction between ANG II and PI3K pathway related to hypertensive stage it seems that PVN is the pivotal autonomic nucleus involved in the sympathoexcitation of this pathology.Research Support: FAPESP, CAPES and CNPQ.
The selection and early discovery of an anti‐HGF aptamer
Authors: Spielberger Kevin , Genga Ryan 
Published: June 2021

Hepatocyte Growth Factor (HGF) specifically binds the c‐Met receptor by forming a homodimer from two heterodimeric molecules. HGF binding to c‐Met results in a multifunctional signaling cascade that activates the upregulation of cellular proliferation under normal conditions. HGF is overexpressed in many types of cancers and increased activity of the HGF:c‐Met pathway causes tumorigenesis and metastasis. We sought to generate an aptamer to HGF that would inhibit the functional interaction between HGF and c‐Met.Aptamers are oligonucleotides that fold into three‐dimensional structures and specifically bind to ligands with high affinity. Aptamers bound to proteins can modify and/or inhibit protein‐protein interactions. Through Systematic Evolution of Ligands by EXponential enrichment (SELEX), an anti‐HGF aptamer that inhibits the HGF:c‐Met pathway was generated from a modified RNA pool. A systematic analysis was carried out to identify the aptamer's smallest functional core and to further optimize the aptamer, resulting in a high affinity, nuclease‐resistant aptamer. Addition of a polyethylene glycol moiety allows for use of aptamer in vivo. The resulting aptamer inhibits cell mobility in a cell scatter assay and reduces tumor growth in the tumor model. These results demonstrate that the anti‐HGF aptamer inhibits tumor proliferation and has the potential to be used as a cancer therapeutic.
The Function and Evolution of the Mastoid Process and Clavicle in Humans: A Natural Experiment
Authors: Osborn Michelle L , Homberger Dominique G 
Published: June 2021

We hypothesize that, in humans, the evolution of a uniquely enlarged mastoid process and clavicle was connected to the acquisition of an upright posture and of freed hands. Our biomechanical model shows that when the arms are moved or loaded, the contracting upper trapezius muscles counterbalance the added weight on the shoulders. The synchronously contracting sternocleidomastoid muscles prevent the head from being retroflexed. To test our hypotheses, we analyzed the asymmetry of biomechanically relevant character pairs in 54 right‐handed male skeletons, based on the premise that bones subjected to greater forces are larger. The humerus diameter, mastoid process width, and rise of the superior nuchal line were more often larger on the right side, while the clavicle length and scapular breadth were so on the left side. These biomechanically relevant characteristics were found in varying aggregates of 2–5 for each individual. This variability may be due to differing occupations. The forces that mold the mastoid process and clavicle in extant humans probably also selected for their robust size within the Homo lineage.Funding: LSU Robert C. West Fund to MLO; LSU Foundation to DGH
Studies on the Role of Acid Sphingomyelinase and Ceramide in the Regulation of TACE Activity and TNFalpha Secretion in Macrophages
Authors: Nikolova‐Karakashian Mariana Nikolova , Rozenova Rozenova Krasimira A. , Deevska Gergana , Karakashian Alexander 
Published: June 2021

Acid Sphingomyelinase (ASMase) activity mediates LPS signaling in various cell types. This study shows that in macrophages, ASMase is a negative regulator of LPS‐induced TNFα secretion. ASMase‐deficient (asm−/−) mice and peritoneal macrophages produce several fold more TNFα than their wild‐type (asm+/+) counterparts when stimulated with LPS, while the addition of exogenous ceramides or SMase reduces the differences. The underlying mechanism for these effects is not transcriptional but post‐translational.The TNFα converting enzyme (TACE) catalyzes the maturation of the 26kD precursor (proTNFα) to the active 17kD form (sTNFα). Asm−/− macrophages exhibited 2 to 3 fold higher TACE activity than asm+/+ macrophages and adding ceramide or SMase suppressed this difference. Our studies further showed that the activity of TACE was rate‐limiting factor for TNFα production and proTNFα that was not processed was internalized and degraded in the lysosomes. Indirect immunofluorescence experiments involving inhibitors of TACE, endocytosis, and lysosomal proteolysis showed that in asm−/− cells significant portion of proTNFα is sequestered within the early endosomes and instead of undergoing lysosomal proteolysis, it is recycled to the plasma membrane and processed to sTNFα. In conclusion, these experiments define a novel role of ASMase in regulation of TNFα secretion by macrophages.
Alcohol potentiates HIV protease inhibitor‐induced ER stress and hepatic lipotoxicity (1001.3)
Authors: Hinton Michael , Liu Runping , Zhang Xiaoxuan , Wang Xiang , Pandak William , Hylemon Phillip , Zhou Huiping 
Published: June 2021

Alcohol consumption, which is highly prevalent in HIV‐infected individuals, has been associated with the amplification of liver toxicities induced by HIV protease inhibitors (PIs). We have demonstrated that HIV PI‐induced endoplasmic reticulum (ER) stress is linked to the dysregulation of hepatic lipid metabolism. However, little is known about the mechanistic pathways by which alcohol promotes HIV PI‐induced hepatic lipotoxicity. The aim of this study was to examine the cellular mechanisms by which alcohol promotes HIV PI‐induced hepatic lipotoxicity. Methods: Primary hepatocytes isolated from rat, wild type mouse or CHOP‐/‐ mouse were treated with individual HIV PIs with or without alcohol. Activation of the ER stress was determined by real time RT‐PCR and Western Blot. Apoptosis was detected by Annexin V‐FITC/propidium iodide staining. Intracellular lipid accumulation was determined by nile red staining. Results: Alcohol and HIV PIs synergistically induced ER stress, lipid accumulation and apoptosis in primary hepatocytes. Both alcohol and HIV PI‐induced lipid accumulation and apoptosis were significantly reduced in CHOP‐/‐ hepatocytes. Conclusions: Activation of the ER stress response is a key cellular mechanism underlying alcohol and HIV PI‐induced hepatotoxicity. Inhibition of ER stress activation may represent a new strategy to prevent alcohol and HIV PI‐associated hepatic lipotoxicity.Grant Funding Source: VA Merit Award
ABO modulation of endothelial phenotypes and glycome profile in human induced pluripotent stem cell‐derived endothelial cells (1003.2)
Authors: Zhang Hanrui , Mooney Ciarán , Ishihara Mayumi , Kumagai Tadahiro , Stalnaker Stephanie , Park Seongha , Veilion Lucas , Hinkle Christine , Stout Matthew , Yang Wenli , VanDorn Daniel , Chou Stella , Bhang Dong Ha , Ryeom Sandra , Tiemeyer Michael , Wells Lance , Azadi Parastoo , Reilly Muredach 
Published: June 2021

Genome‐wide association studies have suggested that, compared to non‐O blood types, the ABO O blood type phenotype and related genotypes are associated with protection from CVD. To test the hypothesis that ABO glycosyltransferase modulates endothelial functional pathways and glycan profile, we differentiated adipose stem cell (ASC)‐derived induced pluripotent stem cell (iPSC) from individuals of different ABO blood types to endothelial cells (ECs). iPSC‐ECs exhibited cobble‐stone morphology, demonstrated capillary tube formation on matrigel, and incorporated acetylated low‐density lipoprotein. FACS analysis indicates expression of both CD31 and vascular endothelial growth factor receptor‐2 (VEGFR2). Immunocytochemical analysis of iPSC‐ECs revealed positive staining for EC markers e.g., CD31, vascular endothelial cadherin (CD144), and von Willebrand factor (vWF). The phenotypic characteristics of iPSC‐ECs were similar to that of human coronary arterial endothelial cells (hCAECs). The adhesion pattern of iPSC‐EC to a variety of extracellular matrix (ECM) was similar across O and non‐O iPSC‐EC, but ABO blood group O showed lesser adhesion to vitronectin and laminin (mean±SD; 2.37±0.19 folds in non‐O vs. O for vitronectin [p=0.02] and 2.30±0.05 folds in non‐O vs. O for laminin [p=0.004]). Further, gap closure assay showed that O type iPSC‐EC had greater migration capacity. We examined glycan profiles of pooled iPSC‐ECs and pooled hCAECs from subjects with matched blood types. N‐linked glycan profiling showed that series of high‐mannose structures were observed as main components of iPSC‐EC and hCAECs. Complex structures were observed as minor components. iPSC‐ECs which gave similar profile to that of hCAECs. Main O‐glycans in iPSC‐ECs and hCAECs was a monosialylated core 1 structure. In summary, we established the feasibility of differentiating EC from subject‐specific ASC‐iPSC as tools to define disease‐relevant ABO modification of EC functions.Grant Funding Source: NIH U01, K24
Intracellular hyaluronan protects murine fibroblasts against apoptosis (1003.3)
Authors: Wang Yan , Lauer Mark , Mack Judith , Maytin Edward 
Published: June 2021

Skin repair typically involves apoptotic cell death. We are interested in the role of hyaluronan (HA), an extracellular matrix molecule, during fibroblast‐mediated repair of injured skin. Has1/3 null mice (Has1/3), which lack hyaluronan synthases 1 and 3 (yet retain Has2) show accelerated wound closure, more fibroblasts, and fewer cleaved caspase‐3–positive dermal cells in healing wounds, suggestive of reduced apoptosis. In cultured Has1/3 fibroblasts, HA levels and Has2 mRNA expression were higher than in WT cells. Apoptosis, induced by serum starvation (SS) or UVB exposure, was reduced in the Has1/3 cells as shown by DNA fragmentation and by cleavage of caspases and PARP. Hyaluronidase, added to remove extracellular HA, surprisingly showed no effect on apoptotic susceptibility to SS or UVB. However, cells treated with 4‐MU to inhibit HA synthesis were sensitized to apoptosis induced by SS or UVB. To further establish a role for HA in protection from apoptosis, Has2 RNA interference (RNAi) was done using Has2‐specific siRNA transfection. Has2 RNAi in WT and Has1/3 fibroblasts inhibited HA synthesis by 90% and significantly increased their sensitivity to apoptosis. External addition of high MW HA failed to reverse this effect. We conclude that Has1/3 skin fibroblasts (which make relatively more HA) are more resistant to apoptosis due to the presence of intracellular HA synthesized by Has2.Grant Funding Source: supported by NHLBI
Glycoproteomics of the Zabrotes subfasciatus larval midgut associated with the insecticidal mechanism of the Olneya tesota PF2 lectin (1006.1)
Authors: Lagarda‐Díaz Irlanda , Guzmán‐Partida Ana , Geiser Dawn , Winzerling Joy , Vazquez‐Moreno Luz 
Published: June 2021

Insect midguts, as well as other animals, are rich in glycoconjugates that have important biological functions required for growth and development. Dietary lectins can bind to gut glycoconjugates and induce various insecticidal effects such as blocking of receptors or transporters and inactivation or activation of enzymes. PF2 is a lectin isolated from the seeds of Olneya tesota (Palo Fierro), and reported to cause 100% mortality of Zabrotes subfasciatus larvae (Mexican bean weevil). We evaluated recognition of the PF2 lectin by α‐amylases from Z. subfasciatus larval midgut and the effect of PF2 on α‐amylase activity. Results demonstrated PF2 decreased total midgut amylase activity. In‐gel amylase activity assay showed three enzyme isoforms, but only one isoform was recognized by PF2. The identity of this Z. subfasciatus α‐amylase was confirmed by LC‐MS/MS. We also evaluated the binding of PF2 to midgut glycoproteins at different larval stages using techniques such as chromatography, 2D‐gel electrophoresis and lectin blotting. Lectin interaction revealed differences in glycoprotein patterns at different larval stages. Analysis by LC‐MS/MS and searches of insect databases revealed several glycoproteins that may serve as potential targets for PF2 recognition. Each of the identified proteins is physiologically significant to weevil larvae and may be associated with the insecticidal mechanism of PF2.Grant Funding Source: Supported by funds from the CONACYT, the Arizona Ag Experiment Station and CALS