bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Substrates for DNA Cytidine Deaminase APOBEC3B with Possible Implications for Alkylating Agent Chemotherapy
Authors: Chapman Joseph , Custance Michael , Shen Birong , Furano Anthony V 
Published: June 2021

Mutations mediated by APOBEC3B (A3B), a single‐strand specific cytidine deaminase, are common in various human cancers, often occurring in long, strand‐coordinated clusters, but also as isolated lesions. The clusters are thought to result from transient single‐stranded DNA generated during replication, recombination, transcription, or, as we recently adduced, DNA repair. A3B has a strong preference for C in a 5′‐TpC‐3′ (TpC) context and catalyzes hydrolysis of the primary amine to generate uracil. Subsequent repair results in mutation of C's to approximately equal numbers of transitions (T) and transversions (A or G), by which A3B‐mediated mutations are identified. We report here that A3B, in some instances, can deaminate cytosine residues in a double‐stranded DNA context in vitro. For example, a C paired to O6‐methylguanine (O6meG), if in a TpC context, is deaminated by A3B, likely due to weak hydrogen bonding between the cytosine primary amine and the guanine carbonyl group. Additionally, an abasic (AP) site opposite a C, or adjacent to the G of a C/G pair, renders the C susceptible to deamination. These results could account for the isolated, non‐clustered A3B mutations observed in many cancers. However, AP sites are common DNA lesions, and O6meG levels increase under alkylating conditions caused by environmental nitrosamines and certain chemotherapeutic treatments. Therefore, these foci could contribute to A3B‐mediated mutations in all cells.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The effects of triptolide on inflammatory responses in endothelial cells
Authors: Wang Youping , Song Chundong , Liu Suxiao , Cui Lin , Gao Yuan , Shen Si , Zhu Minjun , Xu Hui 
Published: June 2021

It is widely held that endothelial dysfunction plays a crucial role in various pathological inflammatory conditions. Although triptolide, an active ingredient of Traditional Chinese Medicine Tripterygium wilfordii Hook.F., has been shown to possess anti‐inflammatory effects in vivo, little information is available that describes the effects of triptolide on inflammatory responses in endothelial cells (ECs). In this study, we determined whether triptolide suppresses inflammatory responses of ECs via inhibition of NF‐κB signaling. In human umbilical vein endothelial cells (HUVECs), treatment with lipopolysaccharide (LPS) enhanced cytokine and chemokine production, adhesion molecule expression, and monocyte adhesion. These effects were associated with increased activation of NF‐κB pathway. Furthermore, we found that pretreatment with triptolide dose‐dependently attenuated LPS‐induced actions. Our results indicate that triptolide suppresses the inflammatory responses of ECs via the inhibition of NF‐κB signaling. [This work was supported by the National Natural Science Foundation of China (No. 81673734) and Henan Provincial Science and Technique Foundation for International Cooperation Program (No. 162102410048)].Support or Funding InformationThis work was supported by the National Natural Science Foundation of China (No. 81673734) and Henan Provincial Science and Technique Foundation for International Cooperation Program (No. 162102410048)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Implications for Growth Differentiation Factor – 11 in Cardiovascular Disease and Metabolic Syndrome
Authors: Jamaiyar Anurag , Xu Yanyong , Wan Weiguo , Enrick Molly , Kolz Christopher L , Zhang Yanqiao , Chilian William M , Yin Liya 
Published: June 2021

While cardiovascular disease is the largest cause of mortality in the United States, its severity is especially pronounced in metabolic syndrome patients. In previous studies, we have shown that coronary collateral growth (CCG) was impaired in Zucker Obese Fatty (ZOF) rats, a rat model of metabolic syndrome while coronary collateral grew extensively in Zucker Lean (ZLN) rats after a 10‐day repetitive ischemia (RI) protocol. To understand the underlying mechanism, we performed microarray and RNA‐seq to profile the gene expression of ischemic heart during coronary collateral growth in ZLN and ZOF rats which underwent the RI protocol. One of the most downregulated genes is Growth Differentiation Factor 11 (Gdf11), which was found to be significantly reduced in ZOF rat hearts compared to ZLN rat hearts and its expression was validated by quantitative RT‐PCR (n = 6). Moreover, Gdf11 mRNA expression is significantly decreased in both diabetic (db/db) and obese (ob/ob) mouse hearts compared to age‐matched wild type mice. To study the role of Gdf11 in vascular dysfunction in metabolic disorder, vascular endothelial cells and induced vascular progenitor cells (iVPCs) were treated with high glucose and high lipid (linoleic, oleic and palmitic acid). Interestingly, Gdf11 expression was decreased significantly under these treatments. Furthermore, we study the role of Gdf11 in the cardiovascular development and diseases using Gdf11 knockout mice with a LacZ gene knock in, which could track the gene expression of Gdf11 by LacZ staining. Whole‐mount of X‐gal staining showed that that Gdf11 is mostly expressed in the vasculature of the heart. Histological analyses confirmed that Gdf11 is expressed in blood vessels throughout the myocardium. These preliminary data suggested that 1) Gdf11 is downregulated in the heart of rodent models of metabolic syndrome and it might contribute to impaired coronary collateral growth in ZOF rats; 2) high glucose or high fatty acid affects the Gdf11 expression; 3) genetic studies show that Gdf11 is highly expressed in myocardial blood vessels, which suggests the role of Gdf11 in vascular growth. Gdf11 is controversial in its function in aging. However, our study is more focused on the function of Gdf11 in cardiovascular development and diseases. Using a Gdf11 knockout model will enable us to interrogate this controversy.Support or Funding InformationThe research is funded by National Institutes of Health grant 2R01HL103227‐05(YZ, LY), 1R01HL135110‐01 (WMC, LY), 1 R01 HL137008‐01A1 (LY), 1R15HL115540‐01 (LY) and 14BGIA18770028 from American Heart Association.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Interactions of Angiotensin Converting Enzyme 2 with Fascin‐1 as a Novel Mechanism in Regulation of its Enzymatic Activity
Authors: Ogunlade Blessing , Guidry Jesse J , Lazartigues Eric , Filipeanu Catalin 
Published: June 2021

Angiotensin converting enzyme 2 (ACE2) catalyzes the conversion of Angiotensin (Ang)‐II to Ang‐(1–7), attenuating the deleterious effects of angiotensin type 1 receptor (AT1R) activation on the cardiovascular functions. Our group originally demonstrated that increased Ang‐II levels stimulate interactions between ACE2 and AT1R followed by enzyme degradation into lysosomes, overall leading to a diminished compensatory activity against overactive renin‐angiotensin system. Although we showed that lysosomal inhibitors largely prevent Ang‐II mediated hypertension in vivo, the cellular mechanisms regulating ACE2 degradation by elevated Ang‐II remain largely unknown.To start elucidating these aspects, we performed a proteomic experiment in Neuro2A cells to find binding partners of ACE2 which interactions are modulated by Ang‐II. Surprisingly, only fascin‐1, an actin‐bundling protein displayed differential interactions with ACE2 in these conditions, suggesting that it may be involved in ACE2 internalization and degradation. The interactions between ACE2 and fascin‐1 were confirmed by confocal microscopy. These experiments also demonstrated that in control conditions ACE2/fascin‐1 complexes are localized at the plasma membrane. Treatment with Ang‐II (100 nM, 4 h) induced internalization of these complexes within cytoplasm. Preliminary experiments determining the total cellular levels of ACE2 in transfected HEK293T by western‐blot demonstrated that Ang‐II treatment for 18 h significantly decrease the cellular enzyme levels. In contrast, in cells overexpressing fascin‐1, ACE2 cellular levels were preserved despite treatment with Ang‐II. Similarly, in HEK293T cells co‐transfected with ACE2 and AT1R, treatment with Ang‐II (100 nM, 4 h) diminished the basal enzymatic activity (18382 ±2430) by 36 ±12%. Overexpression of fascin‐1 did not significantly change ACE2 basal activity (86 ±24%), but in these cells Ang‐II was unable to decrease enzymatic activity (85 ± 28% ).In conclusion, our results reveal for the first time a potential role of fascin‐1 in cardiovascular diseases. As an ACE2 binding partner, fascin‐1 may prevent enzyme degradation in presence of elevated Ang‐II and it appears that its cellular levels are critical in prevention of the deleterious effects of overactive renin‐angiotensin system. Also, these data highlight fascin‐1 as an additional possible therapeutic target in the treatment of cardiovascular diseases.Support or Funding Information5 P30 GM106392‐03 (JJG). NHLBI HL093178 (EL) and a Bridge Grant from Howard University (CMF).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Protective Mechanisms of Physical Activity in Vascular Dysfunction in High‐Fat Diet‐Induced Obesity Via Attenuation of NLRP3 Inflammasome Activation in Mouse Aorta
Authors: Lee Jonghae , Hong Junyoung , Umetani Michihisa , LaVoy Emily , Park Yoonjung 
Published: June 2021

PURPOSEInflammasomes play a pivotal role in inflammatory milieu in vascular pathology via caspase‐1 mediated pyroptosis and IL‐1β processing, but physical activity ameliorates the obesity‐associated inflammation and vascular dysfunction. Thus, we investigated the protective effect of physical activity on the NLRP3 inflammasome‐associated vascular dysfunction and its potential underlying mechanisms.METHODS: C57BL/6J male mice were randomly divided into four groups: (1) control low‐fat diet (LF‐SED), (2) LF diet with free access to a voluntary running wheel (LF‐RUN), (3) high‐fat diet (HF‐SED; 45% of calories from fat), and (4) HF‐RUN. To test effects of HF diet and physical activity in NLRP3 inflammasome‐related signaling pathways, nitric oxide (NO), and oxidative stress in mouse aorta, RT‐qPCR and immunofluorescence staining were performed.RESULTSVoluntary running decreased key markers of NLRP3 inflammasome activation, caspase‐1 and IL‐1β, in whole aortic vessel of obese mice. HF‐RUN restored diet‐induced reduction of NO production compared to HF‐SED. Intracellular superoxide production was elevated in HF‐SED mice compared to LF‐SED and LF‐RUN while it was reduced in HF‐RUN mouse aorta.CONCLUSIONOur findings suggest that physical activity protects diet‐induced aortic vascular dysfunction by suppressing NLRP3 inflammasome activation and improved NO bioavailability via reduced oxidative stress.Support or Funding InformationThis study was supported by grants from the Cardiovascular Research Foundation Asia (#16215 to Y.P.) and the University of Houston (Small Grant Program to Y.P.).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Changes in Peak Oxygen Uptake (VO2peak) Following Renal Transplant: Results after 3‐year Follow‐up
Authors: Bushroe Cody M , Chakkera Harini A , Angadi Siddhartha S 
Published: June 2021

BackgroundData regarding changes in markers of cardiovascular and all‐cause mortality, namely, VO2peak and minute ventilation/carbon dioxide production (VE/VCO2) slope following renal transplantation past 1‐year post‐transplant are lacking. We examined changes in VO2peak and VE/VCO2 before and after ~3‐years after renal transplantation.MethodsEighteen patients (age 56.2 ± 2.5 years; 82.9 ± 4.9 kg; 9 male) completed an exercise test to exhaustion using a ramp treadmill protocol. Subjects underwent pre‐transplant exercise testing (PreTx) following which they were placed on the transplant wait‐list. Average time on the waitlist was 15.6 ± 2 months. Following transplant, subjects underwent follow‐up maximal exercise testing using the same protocol (PostTx). Mean duration to post‐transplant exercise testing was 35 ± 2 months. Gas exchange data, heart rate and respiratory exchange ratios were recorded throughout exercise testing. All variables are reported as mean ± standard error. α was set at 0.05 and a paired t‐test carried out to examine changes in VO2peak and maximal VE/VCO2 slope before and after transplant.ResultsSignificant reductions in relative VO2peak were observed from PreTx = 15.2 ± 0.8 mL/kg/min to PostTX = 12.2 ± 0.4 mL/kg/min (p = 0.002 ). Also, significant increases in Ve/VCO2 were observed from PreTx = 30 ± 1.4 to PostTx = 43 ± 1.6 (p < .001).ConclusionsLong term follow‐up (~3‐years) in this small cohort of patients following renal transplantation demonstrated significant reductions in VO2peak (20%) and worsening of the VE/VCO2 slope (30%) which are modifiable markers of mortality risk. This underscores the need for larger cohort studies to be undertaken in this population given that these markers are independently linked to cardiovascular and all‐cause mortality risk. These data may have implications for cardiovascular stratification and cardiovascular risk reduction in this population.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effect of Acetylation on Liquid‐Liquid Phase Separation and Amyloid Fibril Formation of Tau
Authors: Zhao Ziting , Gao Meng , Huang Yongqi 
Published: June 2021

The function of proteins depends on their phase behavior. When the concentration of a protein exceeds a critical value, it may undergo liquid‐liquid phase separation, leading to demixing of proteins from solution. The resulted liquid droplets are dense and protein‐rich. The microtubule associated protein tau can enrich tubulin by forming liquid droplets, which promotes the formation of microtubule bundles. On the other hand, aberrant aggregation of Tau into neurofibrillary tangles correlates with the progressive destruction of nerve cells. Therefore, studying the aggregating mechanism of tau and drug design targeting tau fibrils are critical for the therapy of Alzheimer's disease. Recent studies have shown that lysine acetylation plays an important role in modulating tau aggregation and microtubule assembly. Considering the potential correlations between liquid‐liquid phase separation and amyloid formation, here we investigated the effect of lysine acetylation on the phase behavior and function of tau in vitro. We used site‐directed mutagenesis, light scattering, thioflavin T florescence assay, and microrheology to study the liquid‐liquid phase separation and aggregation of tau. Consistent with previous observations, acetylation on K274/K321 (mimicked by K274Q/K321Q) significantly impaired tau aggregation whereas acetylation on K280/K281/K369 (mimicked by K280Q/K281Q/K369Q) significantly promoted tau filament formation as compared with the WT protein. Although acetylation on K274/K321 and K280/K281/K369 differentially affected tau aggregation, both acetylation patterns promoted liquid‐liquid phase separation of tau. Moreover, microrheology characterization and protein concentration determination showed that the droplets formed by acetylated tau were denser than the WT protein, suggesting that more intermolecular interactions were form upon lysine acetylation. These results show that lysine residues within the MT‐binding repeats regulate the phase behavior of tau via complex interactions.Support or Funding InformationThis work was supported by National Natural Science Foundation of China (Grant number: 21603121) and Hubei University of Technology.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Resuscitation from Hemorrhagic Shock with High Molecular Weight Polymerized Hemoglobin
Authors: Williams Alexander Thomas , Palmer Andre , Cabrales Pedro 
Published: June 2021

BackgroundHemoglobin (Hb) based oxygen carriers (HBOCs) have been proposed as an alternative to red blood cells (RBCs) for transfusion medicine. Lack of mechanistic analysis lead to clinical evaluation of low molecular weight (MW) HBOCs, which failed in phase III clinical trials due to a myriad of side effects not seen in pre‐clinical trials. Increasing the MW of HBOCs can decrease these side effects by confining HBOCs to the vascular space and increasing nitric oxide generation. HBOCs are advantageous to blood due to their non‐immunogenic properties and potential to use non‐human hb sources, among others. In this study we compare the efficacy of fresh blood, freshly synthesized polymerized bovine hb (PolybHb), and PolybHb stored for 2 years in restoring cardiac function after hemorrhagic shock.MethodsPolybHb was synthesized in the low oxygen affinity (T) state with a 35:1 ratio of glutaraldehyde to bovine Hb, and then subjected to 8–9 cycles of diafiltration. This resulted in a PolybHb solution containing only polymerized Hb molecules < 0.2 uM and >500kDa. PolybHb was then frozen at −80°C and stored until used. Fresh red blood cells were prepared from the blood removed during hemorrhage by centrifugation at 1000g for 7 minutes, removal of the buffy coat, hemoconcentration to a hematocrit of 50%. Rats (200–250g) were hemorrhaged for 50% of their blood volume, held in hypovolemia for 30 minutes, and resuscitated to recover blood pressure to 90% pre‐hemorrhage with fresh autologous blood (fresh blood), PolybHb generated within 3 months of the study (PolybHb 2017), or PolybHb generated two years prior to the study (PolybHb 2015).ResultsShock resulted in impaired oxygen delivery and cardiac function. Resuscitation with fresh blood, PolybHb 2017, and PolybHb 2015 restored cardiac function and systemic vascular resistance. Slightly more PolybHb was infused before restoration of 90% pre‐hemorrhage MAP was achieved, but the volume was not statistically significant. Likely as a result of the higher resuscitation volume, stroke volume and stroke work increased more in animals resuscitated with PolybHb than fresh autologous blood. PolybHb did not impair cardiac contractility nor cause excessive vasoconstriction.ConclusionsStudies indicate that PolybHb is as efficacious as fresh autologous blood in restoring cardiac function in rats after hemorrhagic shock. Additionally, PolybHb can be safely stored at −80°C for two years and retain efficacy, unlike red blood cells.Support or Funding InformationNIH Grants from the National Heart Lung and Blood Institute, T32‐HL105373, P01‐HL110900, R01‐HL126945This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Letrozole Treatment of Pubertal Female Mice Results in Impaired Insulin Action in Skeletal Muscle
Authors: Hernandez‐Carretero Angelina Marie , Martins Vitor , Riopel Matthew , Ho Bryan , Schenk Simon , Thackray Varykina 
Published: June 2021

Approximately 6–15% of women worldwide are affected by polycystic ovary syndrome (PCOS). Although PCOS was originally described as a reproductive disorder with associated obesity, over 30 years of clinical research have confirmed that it is also a metabolic disorder. Hyperandrogenism is the strongest predictor of metabolic dysfunction associated with PCOS. In addition to infertility, women with PCOS diagnosed with hyperandrogenism and ovulatory dysfunction have an increased risk of developing gestational diabetes, type 2 diabetes, cardiovascular disease, and non‐alcoholic fatty liver disease. We previously developed a mouse model that uses the aromatase inhibitor, letrozole to elevate endogenous testosterone levels in female mice. This mouse model has hallmarks of PCOS including hyperandrogenism, anovulation and polycystic ovaries. In addition, we showed that letrozole treatment results in increased weight, abdominal adiposity, dysglycemia, hyperinsulinemia, and insulin resistance. In the current study, we further characterized the metabolic dysfunction that occurs after letrozole treatment to determine whether systemic impairment in insulin sensitivity is associated with lower insulin‐stimulated glucose disposal in peripheral insulin target tissues, such as liver or skeletal muscle. We performed hyperinsulinemic‐euglycemic clamp studies and observed that letrozole‐treated mice were indeed insulin resistant independent of body weight. Additionally, letrozole‐treated mice had an overall lower glucose infusion rate and glucose turnover, when normalized to body weight. Moreover, letrozole‐treated mice exhibited an impaired insulin‐stimulated glucose disposal rate, which is indicative of insulin resistance in skeletal muscle. In contrast, there was no difference observed in insulin‐stimulated suppression of hepatic glucose production. Lastly, ex vivo 2‐deoxyglucose uptake into skeletal muscle upon insulin stimulation was significantly reduced in letrozole‐treated mice compared to placebo. These results are in agreement with our previous findings that indicated skeletal muscle‐specific insulin signaling (as measured by AKT phosphorylation) was blunted in letrozole‐treated mice. In summary, we demonstrated that the letrozole‐induced PCOS mouse model exhibits impaired insulin action in skeletal muscle. Future studies will focus on mechanisms involved in skeletal insulin resistance in this mouse model.Support or Funding InformationSupported by NIH Grant P50 HD012303, AHA 16POST29990015 to M.R., and NIH NIGMS K12GM068524 to A.H‐C.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.