bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histone Variant MacroH2A1 Marks Liver Aging and Orchestrates the Escape from Senescence Induced by DNA Hypomethylation in Hepatocellular Carcinoma
Authors: Vinciguerra Manlio , Borghesan Michela , Rappa Francesca , Panebianco Concita , Cappello Francesco , Pata Illar , Buschbeck Marcus , Sedivy John , Fusilli Caterina , Mazza Tommaso , Pazienza Valerio 
Published: June 2021

The epigenetic basis of age‐associated progression of liver diseases towards hepatocellular carcinoma (HCC) is unclear. MacroH2A1 is a variant of histone H2A1, present in the two isoforms, with fundamental roles in cell homeostasis. MacroH2A1 is a marker of senescence associated heterochromatic foci (SAHF) and synergizes with DNA demethylating chemotherapic agent 5‐aza‐2'‐deoxycytidine (5‐aza‐dC) in silencing tumor suppressor genes in human fibroblasts.We show that protein levels of macroH2A1 isoforms are increased in the livers of old rodents and humans, and in human HCC tissue. Human HCC cells overexpressing macroH2A1 escape a 5‐aza‐dC‐induced senescent phenotype, as determined by cell proliferation/migration/cell cycle assays and b‐gal staining, and exhibit a synergistic global DNA hypomethylation. Deletion of macroH2A1 had opposite, pro‐senescence effects in presence of drug dependent DNA hypomethylation. System analysis of ChIP‐Seq combined with RNA‐Seq data revealed complex macroH2A1 genome occupancy correlated with anti‐senescence transcriptional patterns.We propose macroH2A1 as a strong candidate target for epigenetic‐ and senescence‐based HCC chemotherapy.
PDI via Nrf2 Contributes to the Regulation of Renal AT1 Receptor Function and Blood Pressure
Authors: wang xitao , Asghar Mohammad 
Published: June 2021

We recently reported that age‐associated oxidative stress plays a causal role in high renal angiotensin AT1 receptor (AT1R) function and blood pressure (BP) in the aging Fischer Brown Norway (FNB) rats. This indicates that redox balance is crucial for normal AT1R function and BP. Our objective was to understand the mechanism responsible for the higher oxidative stress in the aging kidneys contributing to impaired AT1R function and high BP in the aged FBNs. Keap1‐Nrf2 system is the master cytoprotective regulatory pathway in the kidney against oxidative stress. Nrf2 transcription factor protects kidney from oxidative stress by activating the transcription of diverse antioxidant and detoxifying enzymes. Kelch‐like ECH‐associated protein 1 (keap1) constitutively represses Nrf2 activity by sequestering Nrf2 in cytosol. We hypothesize that protein disulfide isomerase (PDI), an enzyme involved in isomerization reaction, regulates keap1 and Nrf2. Nrf2, keap1 and PDI were determined by Western blotting and/or immunohistochemistry in both the kidney cortical tissue of FBNs and human kidney 2 (HK2) cells. We found that the aging kidney had low levels of PDI, which was associated with low nuclear levels of Nrf2 and high cytosolic levels of keap1 in the aging FBNs. Moreover, PDI inhibition by bacitracin in HK2 cells significantly reduced Nrf2 accumulation in the nuclei. PDI siRNA treatment in HK2 cells decreased the level of PDI while increased the level of keap1. These data suggest that PDI via keap1 and Nrf2 may be involved in redox balance, contributing to the regulation of AT1R function and BP in aging.Source of Research Support: NIH/NIA, AG039856
Neutralization of Aβ‐amyloid induced toxicity by oligomer 'trapping'
Authors: Multhaup Gerhard , Barucker Christian , Althoff Veit , McKinney Anne 
Published: June 2021

ObjectivesThe transmembrane sequence (TMS) of APP (Aβ residues 29 to 49) is a key determinant of Aβ42 oligomerization and toxicity, with G33 being the critical residue (Harmeier et al., 2009). A systematic analysis of Aβ‐lipid interactions revealed that residues 29 to 49of the neurotoxic Aβ42 bind more strongly to sphingomyelin (SM), GM1, phosphatidylcholine (PC), and a mixture of neuronal lipid membranes (BTLE) than its non‐toxic counterparts Aβ40 and Aβ42 G33I. As the contact site likely represents a drug target site, potential molecules interfering with Aβ‐lipid interactions should enable the design of amyloid selective therapeutics.MethodsSurface plasmon resonance (SPR), Size‐exclusion chromatography (SEC), organotypic slice cultures, MALDI‐MS, electron microscopy, and Drosophila melanogaster as an in vivo model for AD.ResultsTo date, we have found that an eight amino acid peptide (a so‐called “Aβ42‐oligomer interacting peptide” ‐ AIP) with alternating hydrophobic and hydrophilic amino acids neutralizes Aβ42‐induced neurotoxicity by binding to preferentially highly toxic Aβ tetra‐/hexamers. Our data indicates (i) that co‐administration of AIP with Aβ42 prevents the loss of synaptic spine density and rescues long‐term potentiation (LTP) in organotypic slice cultures, and (ii) that the AIP exhibits protective effects in our in vivo model for AD.ConclusionsMembrane regions with a high percentage of SM, such as “lipid rafts” could be of particular importance for the interaction with Aβ42 and may play a crucial role in mediating amyloid in vivo toxicity. The development of compounds that interfere with toxic Aβ‐lipid interactions may have a preventive and therapeutic potential.
Pharmacogenomics of Methotrexate in Rheumatoid Arthritis Patients
Authors: Hagras Magda , Al Attar Suzan , Abuzenadah Adel , Fathaldin Omer , Aseri Ahmed , Sulaiman Mansour , Raddadi Rajaa , Goeb Vincent 
Published: June 2021

Patients with rheumatoid arthritis receiving methotrexate show different responses to treatment. Therefore, this study investigate whether changes in efficacy and toxicity were correlated with allele frequency of different enzymes dealing with methotrexate. Sixty Adult Saudi patients of both sex diagnosed with rheumatoid arthritis receiving methotrexate were recruited, from King Abdulaziz University Hospital, starting from December 2013 to Nov. 2014. Blood sample was withdrawn for genetic analysis of rs717620, rs1045642, rs1232027 and rs1650697 using the Taqman RT‐PCR. Effectiveness and toxicity were evaluated. Forty nine were females, 40.9 ± 9.1 year with disease duration 4.7±5.5 yr, duration of MTX was 36.1 ± 29.6 months and the MTX dose was 12.7±3.7 mg/wk. The mean DAS at baseline was 3.19±1.6. Results revealed that Allele frequency for Homozygous G of ABCC2 (rs717620) is 60%, hetero CTfor ABCB1 (rs1045642) is 56.7%, Allele frequency for Hetero GA of DHFR (G>A) (rs1232027) is 51.7%, Homo C for DHFR (C>T) (rs1650697) is 65.0%. The association of allele with nausea, vomiting, hair loss, photosensitivity, chest symptoms, menstrual symptoms, bone ache and deformities were not significant. In conclusion: No correlation between toxicity and allele frequency.
Characterization of a Novel “Thaw and Go” Cell‐based Transporter Model for Studying SLC Transporters
Authors: Wang Jie , Bourgea Joanne , Cooper Kirsten , Patten Christopher , Li Na 
Published: June 2021

ObjectiveDevelopment and characterization of a novel cell‐based transporter model to study regulatory agencies (USFDA/EMA) recommended and industry important SLC transporters.MethodsCryopreserved HEK293 cells which transiently overexpress OATP1B1*1a (wild‐type), OATP1B3, OAT1, OAT3, OCT1, OCT2, MATE1, MATE2‐K, OATP1A2, OATP2B1, PEPT1, PEPT2, NTCP and empty vector, respectively, were thawed and plated on 24‐well Poly‐D‐Lysine coated plates, and then refed with plating media in the presence or absence of 2mM sodium butyrate at 3‐4 hours post plating. Uptake assays were performed at 24 hrs post plating. Following two washes, cells were pre‐equilibrated with HBSS buffer for 10min, MATE1 and MATE2‐K cells require extra incubation with HBSS buffer containing NH4Cl. The cells were then incubated with substrate or inhibitor for desired amount of time. After the assay was terminated, the cells were lysed and subjected to analysis.ResultsThe novel SLC transporter model, including OATP1B1*1a (wild‐type), OATP1B3, OAT1, OAT3, OCT1, OCT2, MATE1, MATE2‐K, OATP1A2, OATP2B1, PEPT1, PEPT2, and NTCP cells, was characterized for time and substrate concentration‐dependent uptake (Km and Vmax determinations) using prototypical substrates as well as known drug substrates. The model was also validated using selected prototypical transporter inhibitors recommended by regulatory agencies. The kinetic profiles of the selected substrates and IC50 of selected inhibitors were comparable to the published literature and also consistent across independent laboratories. As an example, OATP1B1*1a Km comparison using various substrates is demonstrated below.

OATP1B1*1a Substrates

Estradiol‐17β‐Glucuronide
Estrone‐3‐Sulfate
Rosuvastatin
Fluorescein Methotrexate

Km (µM) using Corning® OATP1B1*1a Cells
6.2
0.4
14.2
5.2

Km (µM) reported in literature
6.3
0.46
13.1
3.8

ConclusionsThe data demonstrated this new SLC transporter model is a validated and compliant in vitro tool to study drug interactions with SLC transporters recommended by regulatory agencies (USFDA/EMA) and industry. This novel cell‐based transporter model eliminates the need for intensive cell culture and maintenance, as well as providing consistent lot‐to‐lot performance.
Lactate Dehydrogenase is Unrelated to Lactic Acid Production in MDA‐MB‐231 Human Breast Cancer Cells
Authors: Mack Nzinga , Mazzio Elizabeth , Bauer David , Soliman Karam 
Published: June 2021

BackgroundA well‐known characteristic of tumor cells is the propensity to produce lactic acid under normoxia and hyperoxia, also referred to as the Warburg effect. High levels of lactic acid are believed to be associated with elevated expression of lactate dehydrogenase A (LDHA), a gene upregulated in diverse aggressive malignancies.MethodsIn this study, ShRNAs were used to permanently knock down the expression of LDHA in human breast cancer MDA‐MB 231 cells. LDHA knockdown was confirmed by Western Blot analysis. Dual analysis of lactic acid production was done via colormetric assay and HPLC, where the data shows no reduction in lactic acid production in knockdowns versus controls. Protein expression of various subtypes of LDH was investigated in order to determine if other subtypes were upregulated.ResultsThere was no change in the protein expression of other subtypes of LDH.ConclusionLactate production in LDHA knockdowns is unrelated to the LDH protein, which calls into question the relationship between glycolysis and the upregulation of lactic acid production in MDA‐MB231 cells. Further analysis will require genomic or proteomic profiling to discover shifts in genes or proteins that are responsible for this sustained production of lactate.
Characterization of Diabetic Cardiomyopathy: A Role for KDAC Activity
Authors: Waldman Maayan , Arad Michael , Leviner Dror , Aravot Dan , Laniado‐Schwartzman Michal , Abraham Nader , Hochhauser Edith 
Published: June 2021

The molecular mechanisms leading to myocyte injury, hypertrophy and dysfunction in the diabetic heart are triggered by the characteristic metabolic abnormalities, and by abnormal energetics. Lysine (K) deacetylases (KDACs) inhibition was shown to be protective in models of doxorubicin cardiotoxicity through the reduction of fibrosis, decreased inflammation and the upregulation of antioxidant defenses. KDACs' role in the pathogenesis of diabetic heart disease is unknown.We used a murine model of leptin resistance (db/db mice). These mice were treated for 1 month with angiotensin II to induce severe cardiomyopathy. Echocardiography heart morphology, biochemical markers of injury were measured in the serum and KDAC activity and signaling was measured in cardiac tissues by Western blot and real time qPCR.Hypertensive diabetic mice developed a unique cardiomyopathy characterized by preserved fractional shortening (FS), thickened left ventricle wall and smaller ventricle cavity. Histological staining revealed infiltration of immune cells and extensive fibrosis. Biochemical markers indicated metabolic syndrome. Hypertrophic markers of diabetic hearts exhibited elevated BNP and MMP2 and lower KDAC activity. Elucidating the role of epigenetic mechanisms and KDAC in the development of diabetic cardiomyopathy in order to search for therapeutic strategies based on pharmacological manipulation of histone acetylation, is needed. Funded by Tel Aviv University.
Effects of Telmisartan and Treadmill Running on Bone Mineral Density in Spontaneously Hypertensive Rats
Authors: Bissoli Nazare , Medeiros Ana Raquel , Nonaka Keico , Pereira Rosa Maria , Ruffoni Leandro , Takayama Liliam , Birocale Marcos Antonio 
Published: June 2021

IntroductionIn the present study, we compared telmisartan, an angiotensin AT1 receptor blocker (ARB), and treadmill running exercise training on bone mineral density (BMD) and biomechanical properties of spontaneously hypertensive rats (SHR). This study was designed to assess changes in BMD and bone biomechanical properties in male SHR treated with telmisartan (T) or undergoing physical activity.MethodsWe used treadmill running (18 m/min/60min/d) and T (5 mg/kg/d) by a 8 weeks period in 3‐month‐old male SHR that were divided randomly into the following 3 groups: Sedentary (S), T and Exercise (E). At the end of protocol, BMD of femur and fifth lumbar vertebra was detected using DXA, and biomechanical properties of these bones were measured by the three‐point bending test. Blood pressure of all groups was measured using a tail‐cuffmanometer.ResultsT and treadmill running, compared to sedentary regimen, reduced blood pressure, but T did not improve bone characteristics, and instead reduced both BMD and bone biomechanical properties. Treadmill running in the study design kept the bone characteristics evaluated and, nevertheless, when comparing to telmisartan use, was effective in maintaining the health of the bone.ConclusionsOur data showed that T negatively affects bone mass and quality evaluated in spontaneously hypertensive rats and is necessary more studies to better evaluate the effect of this drug on the bone proprieties.
Effects of Maternal Separation on Behavior and Cardiovascular Function in the Wistar‐Kyoto Rat
Authors: Rana Samir , McCoy Chelsea , Pugh Phyllis , Wyss J. Michael , Clinton Sarah , Kerman Ilan 
Published: June 2021

Early‐life experiences can have long‐term effects on cardiovascular function and are likely mediated by a host of factors, such as inborn stress sensitivity and epigenetic alterations. To begin addressing this issue we exposed Wistar‐Kyoto (WKY) rats to 180 min. maternal separation (MS) from postnatal day (P)1 to P14, while control rats experienced neonatal handling (NH; 15 min separation). Animals were weaned at P21, developed to adulthood undisturbed, assessed depressive‐ and anxiety‐ like behaviors followed by continuous blood pressure monitoring using radiotelemetry. Upon completion of cardiovascular recordings, whole genome methylation was quantified within select brain regions. Results of our behavioral analyses showed that MS‐exposed rats exhibited decreased depression‐ and anxiety‐ like behaviors along with augmented social behaviors in adulthood. Cardiovascular recordings revealed that MS resulted in the decrease of resting heart rate throughout life, which was accompanied by an increase in baroreflex sensitivity. These protective baseline effects were accompanied by improved cardiovascular recovery to social stress in the MS‐exposed rats. These behavioral and cardiovascular changes were also correlated with an increase in whole genome methylation within the hippocampus, but not other brain regions. Our data demonstrate protective behavioral and cardiovascular effects of MS in WKY rats, which may be related to their inborn stress reactivity. Epigenetic alterations within the hippocampus may contribute to the emergence of these effects.Support: R00MH081927 (IAK), R01MH105447 (SMC), 13PRE16940050 (SR), P30 NS47466 (UAB core)
Effects of Voluntary Exercise Preconditioning on Ang II‐Induced Cardiovascular Pathophysiology in the Mouse
Authors: Wilson Brittany , Forrester Steven , Kawata Keisuke , Kim Boa , Park Joon‐Young 
Published: June 2021

PurposeTo determine the effect of five weeks of voluntary wheel exercise on cardiovascular pathophenotypes caused by angiotensin II.MethodsTwenty‐one C57BL/6J mice were assigned into 4 groups; Sedentary Saline (SS), Sedentary AngII (SAII), Voluntary Wheel Saline (VWS), Voluntary Wheel AngII (VWAII). VW mice had access ad libitum to an exercise wheel for five weeks. AngII was infused at a rate of 700 ug/kg/day for the following two weeks. Echocardiography was performed using Vevo 2100 in parasternal short axis view on the mice after two weeks AngII or Saline infusion.ResultsHeart weight (HW) was significantly higher in VWS and SAII (161.0 & 164.8 mg) compared to SS (139.8 mg; P<.05). HW to body weight (mg/g) was significantly higher in SAII compared to SS (6.1 vs 5.2 mg/g; P<.05). There was a strong pattern that VWAII showed higher HW:BW compared to VWS (6.4 vs 5.7 mg/g; P=.052). Posterior wall thickness in diastole (PWd) was significantly greater in VWAII compared to VWS (1.2 vs 0.9mm; P<.05). Ejection Fraction (EF) was significantly higher in VWS compared to SS (59.3 vs 54.6%, P<.05). VWS showed higher EF compared to VWAII (59.3 vs. 55.4%; P=.053). Fractional Shortening (FS) was significantly higher in VWS compared to SS (30.9 vs 27.8%; P<.05). VWS had significantly higher FS compared to VWAII (30.9 vs 28.2%; P<.05).ConclusionAngII, regardless of exercise preconditioning increased HW:BW ratio. Five weeks of VW exercise preconditioning rescued the deleterious effect of AngII on EF and FS compared to SAII mice. Future studies are warranted to identify molecular mechanism of protective effect of exercise on AngII induced hypertrophy.AHA Scientist Development Grant 12SDG12070327 255 (to J.‐Y. Park)
Knockout of Toll‐like Receptors 2 and 4 Prevents Renal Ischemia‐Reperfusion‐Induced Cardiac Hypertrophy
Authors: Trentin‐Sonoda Mayra , Cirino‐Silva Rogério , Vieira Abrahão Mariana , Monnerat‐Cahli Gustavo , Medei Emiliano , Sorelli Carneiro‐Ramos Marcela 
Published: June 2021

BackgroundIt is known that renal ischemia reperfusion (I/R) generates a systemic inflammatory state, promoting molecular and morphological changes in the heart tissue, but the mechanisms remain unknown. TLRs are largely studied in the heart and are known to participate of inflammatory process, moreover it has been demonstrated their role in cardiac hypertrophy (CH) development.AimThe aim of this study was to investigate whether cardiac TLRs pathways are involved in renal I/R‐induced CH.Methods/ResultsC57BL/6J, TLR2‐/‐ and TLR4‐/‐ mice were subjected to unilateral 60 min renal ischemia followed by reperfusion for 5, 8, 12 and 15 days. A serum peak of inflammatory cytokines was observed after 5 days of reperfusion. Heart weight/tibia length (HW/TL) ratio was increased after 12 days of reperfusion, as well as CH markers BNP and alpha‐actin. Cardiac electrical activity showed longer QT, QTc and action potential duration after 15 days. Cardiac TLRs, NF‐kB, MyD88, HSP60 and 70 mRNA levels were increased in the 15‐days group. After 15 days of reperfusion, the absence of TLRs prevented CH development, as reflected by similar values of HW/TL compared to transgenic non‐ischemic mice, as well as lower expression of HSP and NF‐kB, suggesting that renal IR‐induced increase of these molecules was prevented.ConclusionsThese results indicate that (i) TLRs play a key role on renal IR‐induced CH; (ii) prevention of hypertrophic response was independent of renal function recovery; (iii) TLR2 and TLR4 selectively regulate the systemic inflammatory profile.
Resveratrol Attenuates Vasocontractile Responses to Phenylephrine and Potassium Chloride via a Nitric Oxide Synthase– and Endothelium–Independent Mechanism
Authors: Holder Peter , Denniss Steven , Rush James 
Published: June 2021

This study examined the effect of acute pre‐incubation without or with resveratrol (RSV) at increasing in‐bath concentrations (0, 20, 50, or 100 µM) on the dose‐dependent vasocontractile response stimulated by either the α1‐adrenergic receptor agonist phenylephrine (PE; ‐9.0 to ‐5.0 LogM) or potassium chloride (KCl; 0 to 60 mM) in isometrically‐mounted common carotid artery rings isolated from 20‐30 week old Spontaneously Hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). In both SHR and WKY, the contractile dose‐response curve to PE was increasingly blunted by preincubation with 20, 50, and 100 µM RSV, as evidenced by a RSV concentration‐dependent rightward shift of EC50 and decrease in maximum amplitude and area under the curve (p<0.05). The contractile dose‐response curve to KCl was similarly affected by preincubation with increasing concentrations of RSV (p<0.05). Neither nitric oxide synthase (NOS) inhibition nor endothelium removal was found to affect the ability of 50 µM RSV to attenuate either PE‐ or KCl‐stimulated contraction in SHR or WKY. These data indicate that RSV can attenuate vasocontractile activity stimulated by either receptor‐mediated (PE) activation or voltage‐mediated (KCl) activation via a vascular wall cell‐signaling mechanism that is independent of NOS or the endothelium. This suggests that RSV may act to attenuate contraction in the vascular wall by directly affecting central pathways of contractile activation, such as vascular smooth muscle calcium handling and/or sensitivity.Funded by NSERC Canada
Excess Alcohol Consumption and Cardiac Fibrosis
Authors: McCalister Aaron , Mouton Alan , Kay McKenzie , Gardner Jason 
Published: June 2021

BackgroundAlcoholic Cardiomyopathy (ACM) is characterized by chronic alcohol consumption resulting in ventricular dilatation and cardiac fibrosis (CF). This CF is due to an increase in extracellular matrix components, including Collagens I and III.Statement of PurposeThe purpose of this study is to determine the effect of chronic alcohol consumption on the expression of cardiac proteins Collagen I and III.MethodologyAdult male Sprague‐Dawley rats were exposed to ethanol vapor to achieve approximately 200 mg/dl blood alcohol levels. Rats were exposed to ethanol for 10 weeks, receiving 14 hours on and 10 hour off daily. Left ventricle and livers were harvested and snap frozen for Western Blot analysis. Tissue samples were homogenized in RIPA buffer. Protein concentration was determined by Bradford Assay. Protein samples were separated by SDS‐PAGE and transferred onto PVDF membranes, which were probed with primary antibodies for CYP2E1, alcohol dehydrogenase (ADH), or collagens I and III. Membranes were then exposed to a luminescence detection reagent for protein detection.ResultsLivers were analyzed for the expression of CYP2E1 and ADH. Cardiac tissues were analyzed for the expression of collagen types I and III. Liver expression of protein CYP2E1 was increased due to alcohol exposure, whereas ADH was decreased. Cardiac expression of collagens was increased by alcohol.ConclusionChronic alcohol consumption may lead to cardiac fibrosis.