bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of 1α, 25 dihydroxyvitamin D on muscle hypertrophy and insulin signaling
Authors: Pinkston Catherine Marie , Teegarden Dorothy 
Published: June 2021

Clinical studies suggest that vitamin D may improve muscle function and insulin sensitivity. The aim of this study was to investigate the effect of the active metabolite of vitamin D, 1α, 25 dihydroxyvitamin D (1,25D), on muscle hypertrophy and insulin signaling in differentiated C2C12 myocytes. Co‐treatment of cells for 72 hr with 1,25D (10 nM) + insulin (100 nM) resulted in an increase in hypertrophy (21.46±0.27 protein/DNA) compared to insulin (15.76±1.09, p=0.005) or 1,25D treated cells (14.27±1.68). 1,25D + insulin treatment also increased basal insulin signaling (phosphorylated AKT/total AKT protein levels, 2.1±0.18 fold) compared to insulin (1.06±0.23, p=0.01) or 1,25D (1.03±0.08, p=0.003). In addition, insulin receptor mRNA expression levels increased following 72 hr treatment with 1,25D (4.73±1.70 fold, p=0.02) compared to vehicle (1.00±0.29). Consistent with this, 1,25D treatment for 72 hrs followed by 20 minute insulin stimulation increased phosphorylated AKT/total AKT (3.41±0.46 fold) compared to vehicle treated cells (1.00±0.91, p=0.03). This study suggests 1,25D enhances muscle hypertrophy as well as basal and insulin‐stimulated insulin signaling, potentially by increasing the expression of the insulin receptor in skeletal muscle cells. These results may, in part, explain the beneficial effects of vitamin D on muscle and insulin resistance. Supported by NIH DK069965.Grant Funding SourceNIH DK069965
Regulation of the G protein βγ subunits through the covalent modification of Gβ
Authors: Dessal Axel Lionel , Smrcka Alan 
Published: June 2021

The βγ‐subunits of G protein (Gβγ) dissociate from the a‐subunit (Ga) upon activation of G protein‐coupled receptors. Once free, Gβγ is able to regulate many target proteins, including phospholipase Cβ2 (PLCβ2), phosphoinositide 3‐kinase γ (PI3Kγ) and G protein‐coupled receptor kinase 2 (GRK2). Because overactivation of Gβγ signaling has been implicated in the pathophysiology of several diseases, inhibitors of Gβγ might be very valuable from a pharmacological point of view. Our group has used a combination of virtual and manual screening to find small molecules that bind to a protein‐protein interaction "hot spot" on the β subunit. These compounds inhibit the binding of a phage displaying the SIGKAFKILGYPDYD peptide (SIGK) to Gβγ in an enzyme‐linked immunosorbent assay (ELISA) at concentrations in the nM to µM range. Recently, we discovered that some of the small molecules, like cystamine and selenocystamine, disrupt Gβγ function by a redox mechanism. Their effect can be reversed by the addition of dithiothreitol (DTT). Mass spectrometry indicates that selenocystamine forms a selenylsulfide bridge at preferentially one position, and mutagenesis studies suggest that both cystamine and selenocystamine act on cysteine 204 of the βsubunit. This is the first evidence that protein‐protein interactions with Gβγ can be regulated in a reversible redox manner.This work was supported by NIH grant GM60286‐08.
Role of sigma receptors in attenuation of methamphetamine‐induced neurotoxicity in vitro
Authors: Vedam Shreedeepalakshmi , Mastumoto Rae R. , Coop Andrew 
Published: June 2021

Methamphetamine (Meth) abuse is a growing health concern because of its capability to cause neurotoxicity and death. Currently, no pharmacotherapy exists to treat Meth‐ induced neurotoxicity. Initial drug targets focused on dopamine, which were limited in effectiveness; alternative targets for medication development are sigma receptors due to Meth's interactions with them. The goal of this study was to evaluate the involvement of sigma receptors in Meth‐induced neurotoxicity in vitro. NG108‐15 cells were incubated with various concentrations of Meth up to 48 hrs. Cytotoxicity was quantified using cell morphology scores. Cultured cells treated with Meth exhibited significant worsening of cells morphology scores in a time‐ and concentration‐dependent manner. AC927, a sigma receptor antagonist attenuated the cytotoxicity of Meth at concentrations that did not significantly alter cell morphology. Together, the results suggest that NG108‐15 cells can serve as an in vitro model for studying Meth‐induced neurotoxicity and AC927 can serve as a good lead molecule for developing pharmacotherapies for Meth.Funding: NIH DA011979, DA013978.
Modeling Skeletal Muscle Angiogenesis from the Molecular to the Tissue Level
Authors: Qutub Amina Ann , Liu Gang , Vempati Prakash , Popel Aleksander S. 
Published: June 2021

We present a multiscale model of angiogenesis that integrates individual modules representing blood flow, oxygen transport, growth factor distribution and signaling, cell sensing, cell movement and cell proliferation. This integration will be used to better understand underlying biological mechanisms from the molecular level up through the organ systems level; examine the effects of pathological conditions on skeletal muscle capillary growth; and test new therapeutic strategies. Model methodology includes partial differential equations, stochastic models, complex logical rules, and agent‐based architectures. Spatial and time scales range from ligand‐receptor interactions and intracellular signaling occurring on the order of seconds and minutes, to cell‐level movement and cell‐matrix interactions over minutes to hours, to vessel formation and tissue level responses over hours to days.We introduce the individual modules and describe our methodology for integration, which involves wrapping models (written in different programming languages) in a Java‐based dynamic link library format that allows for a central controller to readily pass parameters between the models. We present results from the coordination of modules: the effects of hypoxia in skeletal muscle from the molecular‐detailed changes in HIF1‐initiated VEGF secretion and VEGF‐VEGFR signaling; to endothelial cell activation, cell movement in response to VEGF gradients, and capillary branching as a function of the Notch ligand DLL4; to the resulting new capillary network and altered pattern of blood flow. This angiogenesis multiscale modeling and integration will be a tool in rational drug development and therapeutic regime design, and encourage related angiogenesis experiments.
Changes in muscle carnosine of subjects with 4 weeks supplementation with a controlled release formulation of beta‐alanine (Carnosyn™), and for 6 weeks post
Authors: Harris Roger C , Jones Glenys A , Kim Hyo J , Kim Chang K , Price Karen A , Wise John A 
Published: June 2021

Muscle Carnosine (M‐Carn) synthesis is limited by the availability of ?‐Alanine ( ?‐Ala) but can be increased by supplementation with ?‐Ala. This is of interest to athletes since increased levels of muscle M‐Carn have previously been shown to improve exercise performance. Above 10mg/kg bwt, however, ?‐Ala in solution or rapidly‐dissolving capsules causes symptoms of paraesthesia, despite the amount being less than that available from normal meat ingestion.PURPOSETo investigate the change in M‐Carn in subjects supplemented with a controlled‐release ?‐Ala formulation.METHODSeven males received 2x800mg ?‐Ala controlled release tablets, 4/d for 4w. Controlled release tablets were Carnosyn(tm) supplied by Collegiate Sports Nutrition. A muscle biopsy from the vastus lateralis was taken at 0 and 4w, and 3 and 6w post supplementation. No control group was included as several previous studies have demonstrated no change in M‐Carn without ?‐Ala supplementation.RESULTSSubjects did not experience paraesthesia. Mean (±SD) M‐Carn at 0 and 4w, and, 3 and 6w post supplementation were 25.9±4.3, 41.3±5.5, 38.3±6.7 and 35.4±5.5 mmol.kg−1 dry muscle. Post supplementation M‐Carn declined via first‐order kinetics with a half‐life (t½) determined to be 8.6w.CONCLUSIONThe controlled release ?‐Ala formulation was effective in raising M‐Carn. Following supplementation, levels of M‐Carn declined slowly with a t½ ~9w.
Caveolin‐3 KO Mice Develop Dyslipidemia with Impaired Substrate Utilization in Skeletal Muscle.
Authors: Capozza Franco , Trimmer Casey , Lisanti Michael P 
Published: June 2021

Caveolin‐3 (Cav‐3) is expressed predominantly in skeletal muscle fibers where it drives Caveolae formation at the muscle cell's plasma membrane (sarcolemma). We and others have previously shown that mice with a genetic ablation of Cav‐3 develop glucose intolerance, insulin resistance, and obesity. The main objective of this study is to determine the effect of Cav‐3 ablation on whole‐body/tissue lipid metabolism. To address this issue, several metabolic parameters were analyzed in the plasma of young and older Cav‐3 KO mice. In addition, by employing radiolabeled metabolic substrates, we directly determined the contribution of skeletal muscle to the plasma dyslipidemia of Cav‐3 KO mice. In summary, the current study shows that an absence of Cav‐3 leads to dyslipidemia in mice. The primary defect can be localized to the skeletal muscle and is secondary to altered muscle substrate utilization caused by Cav‐3 ablation.Support: American Heart Association; BGIA
Interleukin‐6 Signaling Mediates Human Muscle Satellite Cell Proliferation Following Acute Muscle Damage
Authors: McKay Bryon Robert , De Lisio Michael , Johnston Adam P. W. , Phillips Stuart M. , Tarnopolsky Mark A. , Parise Gianni 
Published: June 2021

Interleukin‐6 (IL‐6) has been implicated in satellite cell (SC)‐mediated muscle hypertrophy in animals; however, the role of IL‐6 in the SC response to acute injury in humans remains to be elucidated. Eight subjects (22 ± 1 y; 79 ± 8 kg) performed 300 maximal leg lengthening contractions (3.14 rad.s−1). Blood and muscle samples were collected before and at 4 (T4), 24 (T24), 72 (T72), and 120 hr (T120) post intervention. IL‐6, IL‐6 receptor (IL‐6R), Cyclin D1, SOCS3 mRNA and serum IL‐6 protein were measured. JAK2 and STAT3 phosphorylated and total protein and immunohistochemistry for phosphorylated STAT3 (p‐STAT3), IL‐6 and Pax7 were analyzed across all time‐points. Serum IL‐6 increased 200% by T4, while IL‐6 mRNA increased 4.5‐fold at T4, and IL‐6R mRNA increased 5‐fold at T4. Serum IL‐6 strongly correlated to muscle IL‐6 mRNA (r2 = 0.89, p = 0.02). The number of Pax7+ cells (% myonuclei) increased 74% at T24, peaking at T72 (157% increase from PRE). SC that were IL‐6+ (% of Pax7+ cells) increased from 2% at PRE, to 60% at T4 and peaked at T24 (80% of SC). By T72, IL‐6+ SC dropped to PRE values. There was no change in JAK2, p‐JAK2, STAT3 or p‐STAT3 whole muscle protein; however, p‐STAT3 localized to the SC at T4. Cyclin D1 increased T4 and T24 (6‐fold), and SOCS3 increased 6‐fold at T24. These data suggest that IL‐6, signaling via the JAK/STAT3 pathway, mediates SC proliferation following acute myotrauma in humans.Supported by NSERC
Chronic hypoxia decreases response to central chemoreceptor stimulation in the nucleus tractus solitarius (NTS)
Authors: Wilkinson Katherine A. , Nichols Nicole L. , Putnam Robert W. , Powell Frank L. 
Published: June 2021

One hallmark of acclimatization to chronic hypoxia (CH) is hyperventilation and a lower arterial carbon dioxide (CO2) level. These effects persist upon return to normoxia, suggesting a change in the regulation of CO2 during CH. We tested the hypothesis that plasticity in one central chemoreceptor site, the NTS, contributes to altered CO2 regulation in CH. In urethane‐anesthetized rats, we stimulated chemoreceptors in the NTS by a unilateral microinjection of acetazolamide (ACZ, 1 nl of 0.3 μM), to produce focal acidosis. The product of rectified, integrated phrenic nerve amplitude and frequency (Phr) was measured 30 min after ACZ in normoxic control (N; n=5) and CH rats (n=5). ACZ increased Phr significantly more in N rats than CH rats (N=263±14%; CH=83±18%; p<0.001). ACZ in adjacent brainstem regions had no effect on Phr. All rats showed the capacity to increase Phr to a 10% inspired CO2 challenge following ACZ, suggesting that the dose of ACZ did not produce a maximal phrenic response. These results indicate plasticity in chemosensitivity in the NTS but they cannot easily explain the lower CO2 set point with CH.Supported by NIH HL81823 (FLP) and AHA 0615069Y (KAW).
Generating Flash files of Your Lectures: Good Practice Strategies Helping Students Engage with Their Learning
Authors: Dallemagne Catherine 
Published: June 2021

Our students come from diverse backgrounds. They need flexibility in their learning. First year students tend to worry when they miss lectures or part of lectures. Having the lecture as an on line resource allows students to miss a lecture without stressing about it and to be more relaxed in the lecture, knowing that anything they may miss will be available later.The resource: The Windows based program from Blueberry Software (not Blackberry!) ‐ BB Flashback ‐ allows the simultaneous recording of the computer screen together with the audio, as well as Webcam recording.Editing capabilities include adding pause buttons, graphics and text to the file before exporting it in a flash file. Any diagrams drawn on the board or shown via visualiser can be photographed and easily incorporated.The audio from the file can be extracted if required to be posted as podcast. Exporting modes other than Flash are also available, allowing vodcasting if you wish.What you will need:‐ the recording software: it can be installed on the lecture hall computer just prior to lecture if needed‐ a computer: either the ones in lecture halls, especially if fitted with audio recording, or a laptop (I have used audio recording via Bluetooth for mobility).Feedback from students has been positive and will be presented on the poster.
The Protective Role of T cells against Angiogenic Potential of Pulmonary Endothelial Cells
Authors: Taraseviciene‐Stewart Laima , Slepikas Liudas , Fragoso Miguel , Gerasimovskaya Evgenia 
Published: June 2021

RationaleIn contrast to the euthymic rats, chronic hypoxia in the athymic rats induces non‐reversible severe pulmonary hypertension and remodeling. Here we investigate whether T cells play a protective role against the development of pulmonary hypertension by suppressing angioproliferative potential of endothelial cells (EC).MethodsRats were exposed to chronic hypoxia for 3 weeks. Pulmonary artery pressures (PAP) and right ventricle hypertrophy (RV/LV+S) were measured. Vascular remodeling was assessed by immunohistochemistry (IHC). The de‐differentiated endothelial cell population (DD‐EC) was obtained by excessive trypsinization of human umbilical vein endothelial cells (HUVEC). Carboxyfluorescein diacetate (CFDA)‐labeled DD‐EC were injected into the euthymic and athymic rats.ResultsHypoxic exposure of athymic rats resulted in a significant pulmonary vascular remodeling, high PAP (PAP = 42±0.6 versus 33±0.4 mmHg) and right ventricle hypertrophy (RV/LV+S = 0.7±0.08 versus 0.45±0.02). CFDA‐labeled DD‐EC were present in the circulation, but not in the lungs of euthymic rats. In contrast, in the athymic rats, CFDA‐DD‐ECs were found in the lung vascular wall.ConclusionsT cells play a protective role against hypoxia‐induced pulmonary hypertension and remodeling. In the immune competent animals the angioproliferative DD‐ECs do not reside in the lung, but once they escape immune control (athymic rat), they colonize in the lung vasculature. Our data suggest that T cells play a protective role in suppressing angioproliferative potential of vascular endothelial cells.Funded by AHA 0735388N and AHA 0665464Z
Heart hypertrophy in response to pressure overload in TSP4 knockout mice
Authors: Frolova Ella , Sopko Nikolai , Penn Marc , Stenina Olga , Plow Edward 
Published: June 2021

Thrombospondin‐4 (TSP4) is abundant in the heart in blood vessels, including capillaries and the aorta. TSP4 expression increases in hypertrophic and failing hearts and in response to ischemia. TSP4 KO and WT mice were subjected to transverse aortic constriction (TAC). 2 and 20 weeks later TSP4 KO hearts revealed more extensive hypertrophy and higher HW/BW (heart weight/ body weight) ratio compared to WT mice, and the differences were magnified with age: 6.7(0.2 in WT versus 7.4(0.2 in KO of 23 weeks, 4.7(1 in WT versus 9(3 KO at 55 weeks, and 4.3(0.8 in WT versus 8.5(3 in KO at 82 weeks. The increased hypertrophy in TAC TSP4 KO mice was due to higher deposition of collagen. The fibrosis fraction was calculated as the ratio of Masson's trichrome stained connective tissue area to total myocardial area: WT ‐ 7.4%(2.6, KO ‐ 9.6%(5.9 at 23 weeks 20 weeks after TAC; WT ‐ 3.8%(2, KO ‐ 11.2%(8.4 at 55 weeks, 20 weeks after TAC; and WT ‐ 4.6%(2.1, KO ‐ 16.8%(3 at 82 weeks, 2 weeks after TAC.TSP4 KO hearts experienced the overload even in normal conditions: the cardiomyocytes in sham operated KO trended to be smaller in size; in hearts of old sham KO mice fibrosis fraction was 2 times larger than in WT mice hearts and non‐operated KO hearts showed 1.8 fold increase in glucose uptake.We conclude that TSP4 is involved in adaptive responses of the heart to pressure overload, suggesting its important role in tissue remodeling. P50 HL077107; R01 DK067532
Collagenase 3 (MMP13) modulates activation of Transforming Growth Factor b (TGFb) by hypertrophic growth plate chondrocytes
Authors: Averna Tiffany , Lehner Joseph , Lau Shukkwan , Routson Stephanie , Selim Abdulhafez , D'Angelo Marina 
Published: June 2021

MMP13 expression is concomitant with onset of chondrocyte hypertrophy in the growth plate and can activate TGFβ produced by chondrocytes. Our previous binding studies indicated significant binding of a 19 amino acid MMP13‐derived peptide with the large latent TGFβ complex. Bioinformatics data indicate the site of interaction within close proximity of a non‐catalytic region in MMP13. We hypothesized that MMP13‐derived peptide could competitively inhibit MMP13 binding leading to reduced TGFβ activation. Serum‐free, primary hypertrophic chondrocyte cultures were treated with 10, 100 and 250nM of the peptide and endogenously activated TGFβ measured via ELISA and immunoblot. At 24 hours, the 250nM dose of peptide significantly induced a 5‐fold decrease in activated TGFβ without any change in the total TGFβ produced and this effect was reduced by 48 hours. These data suggest that the MMP13‐19 peptide can interfere with TGFβ activation without effects on total TGFβ produced. In osteoarthritis, aberrant activation of TGFβ?leads to cartilage degradation and inhibitors of the MMP catalytic domain have been used to stop this degradation, but with detrimental side‐effects. This study describes a method of reversible targeted disruption of MMP13 interaction with the TGFβ large latent complex independent of the catalytic site promising novel therapeutic approaches in the treatment of osteoarthritis. Supported by CCDAGrant Funding SourceCCDA
Articular Chondroprogenitors as tools for cartilage tissue engineering
Authors: Bishop Joanna Charlotte , Khan Ilyas , Williams Rebecca , Archer Charles 
Published: June 2021

The use of stem/progenitor cells to form good quality cartilage matrix has been targeted as a therapeutic goal for cartilage repair treatment. We have characterised a progenitor cell population that resides in the surface layer of neonatal bovine articular cartilage [1]. Here, we assess the progenitor cell's chondrogenic potential.Cloned chondroprogenitors exhibited exponential growth for the first 20 population doublings (PD), then slower linear growth with evidence of replicative senescence at later passages. Mean telomere lengths of exponentially growing chondroprogenitors were significantly longer than dedifferentiated chondrocytes that had undergone a similar number of PD (P<0.05). Chondroprogenitors also had 2.6‐fold greater telomerase activity and maintained sox9 and Notch‐1 mRNA expression whereas dedifferentiated chondrocytes demonstrated little or no detectable expression. Induced differentiation to cartilage in 3D pellet cultures, demonstrated sox9, Notch‐1, aggrecan and PCNA expression.Maintenenace of telomerase activity, Notch‐1 and sox9 gene expression distinguish clonal chondroprogenitor cells from dedifferentiated chondrocytes. When placed in chondrogenic medium chondroprogenitors appear to engage in co‐ordinated growth and differentiation in stark contrast to dedifferentiated chondrocytes. UK DBERF
Periodontium derived osteoprogenitors isolated from αSMA‐GFP mice expressed bone and stem cell markers
Authors: SANMIGUEL SYMONE MARQUEZ , Li Haitao , Igwe John , Ferrer Vesna , Aguila Hector , Kalajzic Ivo 
Published: June 2021

PurposeThis study was conducted to determine if the αSMA promoter would direct GFP expression in osteoprogenitor cells of dental follicle and periodontal ligament.MethodsEpifluorescence was evaluated in histological sections of mandibles derived from neonatal and 4‐6 week old mice. Transgene expression was also evaluated in primary cultures derived from dental follicle (mDF) and periodontal ligament (mPDL). Osteogenic differentiation was determined by RNA expression of bone markers, histochemical staining for alkaline phosphatase (ALP) and detection of mineralized nodules by xylenol orange. Flow cytometry (FACS) was used to determine cellular profile of freshly isolated or cultured αSMA positive cells.ResultsαSMA‐GFP expression was observed in the dental follicle, and in apical regions of the root. Strong expression of αSMA‐GFP was observed during early culture stages and diminished as mineralization progressed. Intense ALP activity, presence of mineralized nodules and increased expression of bone sialoprotein and dentin matrix protein‐1 following two weeks of osteogenic induction was observed. FACS analysis revealed that freshly digested mDF cells expressed the mesenchymal markersThy‐1 (40%) and Sca‐1 (8.79%).ConclusionαSMA promoter has the potential to identify a population of mesenchymal progenitor cells residing within the dental follicle and periodontal ligament.Grant Funding SourceNIH GRANTU24DE06495
Apin participates in establishment of the incompletely‐differentiated junctional epithelium around teeth
Authors: Nishio Clarice , Wazen Rima , Moffat Pierre , Nanci Antonio 
Published: June 2021

A novel gene, Apin (Odam), belonging to a gene cluster encoding for proteins involved in the regulation of mineralization, was cloned in our laboratory. Initial studies suggested that Apin might mediate adhesion of the portion of the gingiva that attaches to the tooth surface (junctional epithelium; JE). It is also expressed in many epithelial cancers, including odontogenic tumors.PurposeTo validate the implication of Apin in JE formation by comparing its distribution in normal and regenerating gingiva. Materials and methods: Gingivectomies were done on the maxillae of adult rats. The contralateral maxilla was left intact as a control. Animals were sacrificed on days 0‐7 after surgery and maxillae were processed for paraffin embedding and immunolabeling for Apin.ResultsIn control samples, Apin was localized among cells of the JE and along its interface with the tooth. No labeling was seen in the residual gingiva at day 0. Over time, Apin labeling reappeared in the regenerating JE emerging from the gingiva. By day 7, the labeling pattern was similar to controls.ConclusionThe interfacial localization of Apin suggests that it plays a role in adhesion. Its presence among cells of the JE, an incompletely differentiated epithelium, and its expression in epithelial tumors indicates that Apin may also be implicated in other cellular activities such as differentiation. Support by CIHR and Department of Foreign Affairs.