bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuregulin improves neuromuscular transmission in diaphragm muscle of young rats
Authors: Ermilov Leonid G , Mantilla Carlos B , Sieck Dylan C , Zhan Wen‐Zhi , Sieck Gary C 
Published: June 2021

Neuregulin (NRG) is important for expression of acetylcholine (ACh) receptors during development of the neuromuscular junction (NMJ). NRG treatment significantly increases ACh‐induced currents in hippocampal neurons, but it is not known if NRG exerts a similar effect at NMJs. Diaphragm muscle (DIAm)‐phrenic nerve preparations from 7‐ and 14‐day old rats were used to determine the effects of NRG (heregulin β177–244) on neuromuscular transmission and DIAm contractile properties. Neuromuscular transmission failure (NMTF) was assessed by the difference in force elicited by repetitive phrenic nerve stimulation (0.2 ms pulses in 40 Hz, 330 ms trains) and superimposed, intermittent direct DIAm stimulation (1 ms pulses in 40 Hz, 330 ms trains applied every 15 seconds). NMTF was higher in 7‐day old compared to 14‐day old rats (76% vs. 65%; p<0.05). Exogenous NRG treatment significantly improved neuromuscular transmission in 7‐day old rats (NMTF: 52%; p<0.05), but not in 14‐day old rats (65%). Isometric DIAm contractile properties were not affected by NRG treatment in either age group. These results indicate that NRG has important synaptic effects during early postnatal development of the DIAm. Whether NRG effects on neuromuscular transmission result from acute changes in AChR expression or alternative mechanisms remains to be explored.Supported by NIH grant AR51173 and a Career Development Award from Mayo Clinic.
Neurotrophins improve neuromuscular transmission in rats with myasthenia gravis
Authors: Mantilla Carlos B , Ermilov Leonid G , Zhan Wen‐Zhi 
Published: June 2021

Myasthenia gravis is a disease of the neuromuscular junction (NMJ) associated with autoimmune destruction of the motor end‐plate. Inhibitors of acetylcholine (ACh) esterase are commonly used to mitigate symptoms by increasing ACh availability at the NMJ. Brain‐derived neurotrophic factor (BDNF) improves neuromuscular transmission in the rat diaphragm muscle (DIAm) by maintaining ACh release with repeated activation. We hypothesized that BDNF will mitigate the deficit of neuromuscular transmission in a passive transfer model of myasthenia gravis. Female Lewis rats were injected with vehicle, McAb1 (that does not induce myasthenia), and a myasthenogenic McAb3 antibody. Neuromuscular transmission failure (NMTF) was determined in DIAm‐phrenic nerve preparations by comparing the isometric force evoked by phrenic nerve stimulation and that evoked by superimposed direct muscle stimulation. After 2 min of repetitive stimulation, neuromuscular transmission was significantly impaired in myasthenic animals (NMTF: 80%) compared to vehicle and McAb1 animals (NMTF: ~60%). Exogenous BDNF treatment significantly improved neuromuscular transmission in all groups and NMTF in McAb3‐treated rats was no longer different from control or McAb1‐treated animals. We conclude that BDNF improves neuromuscular transmission in adult myasthenic rats.Supported by a Career Development Award from Mayo Clinic.
A polymer chip‐based technology for the investigation of small resistance arteries
Authors: Voigtlaender‐Bolz Julia , Yasotharan Sanjesh , Vagaon Andrei , Lochovsky Conrad , Guenther Axel , Bolz Steffen‐Sebastian 
Published: June 2021

Growing consensus links hypertension, a primary cardiovascular risk factor, to elevated peripheral resistance. Advanced research on peripheral resistance arteries (RA) is therefore essential to improve our knowledge regarding hypertension and existing treatment strategies. Current experimental approaches (i.e., pressure myography) are time intensive, not high throughput ready and require highly skilled personnel. To overcome these limitations, we have designed and fabricated a microfluidic device that allows RAs to be reversibly loaded, fixed, and perfused on a polymer chip (AoC). The current study aims to validate the AoC in relation to the classical cannulation approach.Dose response curves for phenylephrine (PE) and acetylcholine (ACh) were virtually identical for mesenteric RAs tested on the AoC and those studied on a conventional pressure myograph. Arteries kept in culture on the AoC for 24h prior to functional testing showed fully maintained responses to PE and ACh. On‐chip vessel loading with Fura‐2 revealed irregular Ca2+ oscillations that were synchronized following PE treatment.This study presents a fast, easy to manage, low cost, scalable and high throughput‐ready technology that will drastically facilitate microvascular research. Based on its innovative features, the AoC has great potential for application in drug development and on‐site clinical use (personalized medicine).
Protein Tyrosine Nitration and Glutathionylation Impairs Pro‐Survival Mechanisms of Akt in CryABmut Cardiomyopathy in Mice
Authors: Soorappan Rajasekaran Namakkal , Varadharaj Saradhadevi , Zhang Huali , Zweier Jay L , Benjamin Ivor J 
Published: June 2021

BackgroundSerine‐threonine Akt affords powerful cellular protection but the role of this pro‐survival pathway in hR120GCryAB‐TG cardiomyopathy remains poorly defined. We hypothesized that chronic oxidative modifications and sequestration of Akt could impair the pro‐survival mechanisms in the hR120GCryAB‐TG leading to heart failure.MethodsTo gain further insights, we have determined biochemical markers of oxidative modifications.ResultsWestern blot and immunohistochemical analyses indicated increased protein kinase‐B (PKB/Akt) is sequestered into the protein aggregates containing hR120GCryAB in myopathic hearts compared with the non‐transgenic (NTG) controls. Increased S‐glutathionylation and tyrosine nitrosylation were present in the 3 and 6 months old TG mice, suggesting potential role in inactivation of pro‐survival mechanisms of Akt. Surprisingly, we found increased Akt kinase (substrate: GSK3‐α/β) activity in vitro in the hR120GCryAB‐TG hearts compared with the NTG, suggesting chronic Akt activation is coupled with cardiac hypertrophy and progression of cardiaomyopathy.ConclusionsTaken together, these findings implicate chronic activation and sequestration of Akt in the pathogenesis of hR120GCryAB‐induced cardiotoxicity.
Bone marrow cell therapy modulates remodeling of the myocardium remnant to experimental infarction in the rat: effects on the contractility and calcium handling proteins
Authors: dos Santos Leonardo , Gonçalves Giovana A. , Santos Alexandra A. , Davel Ana P. , Krieger Jose E. , Rossoni Luciana V. , Tucci Paulo J. 
Published: June 2021

We evaluated the effects of bone marrow‐derived mononuclear cells (MNC) on the left ventricular (LV) function, and functional and molecular remodeling of tissue remnant to myocardial infarct (MI) in the rat. Saline (MI group) or 6×106 MNC (MI+MNC) were injected in the infarct border zone of Lewis inbred rats 48h after coronary occlusion and compared to a sham group (SO). After 6 weeks, infarct size of MI+MNC (38±2%) turned smaller than MI (44±2%), and LV dilatation and dysfunction were partially attenuated. Interestingly, developed force of isolated LV muscle samples was impaired in MI (2.6±0.4g/mm2) but fully preserved in MI+MNC (5.6±0.7) when compared to SO (5.9±0.5), in spite of sizable infarcts. Contractile responses to calcium and beta‐agonist were better in muscles from MI+MNC, as well as the post‐rest potentiation of force. Concordantly, decreases in sarcoplasmic Ca2+ATPase (46%), total (47%) and Ser16‐phosphorylated phospholamban (65%) were prevented by MNC (5, 10 and 9% respectively). While no changes were noted on α1‐Na+K+ATPase, decrease in α2 isoform due to MI was not influenced by MNC. We added evidences that MNC injection restricts post‐MI cardiac dysfunction. Also, our results indicated that this therapy preserved mechanics of myocardium remnant to infarct associated to prevention on specific calcium handling protein alterations.Supported by FAPESP and CNPq.
Adenosine attenuates the lipopolysaccharide (LPS) induced endothelial barrier dysfunction in murine model of acute lung injury
Authors: Gonzales Joyce N , Gorshkov Boris A , Umapathy NS , Black Stephen M , Verin Alexander D 
Published: June 2021

RationaleAcute lung injury (ALI) affects approximately 200,000 people in the United States every year. A basic cause is pulmonary endothelial cell (EC) barrier disruption and the ensuing inflammation and increased permeability of the EC. Our previous studies on the human pulmonary arterial endothelial cells have shown that adenosine (AD), an endogenous purine nucleoside, attenuates the EC barrier. The goal of our experiments was to evaluate AD attenuation on the EC barrier in LPS treated mice.ResultsOur preliminary data indicate that mice challenged with LPS demonstrated an inflammatory response typical for ALI compared with normal saline (NS) treated controls. Microscopic examination of bronchoalveolar (BAL) showed fewer neutrophils in control and LPS/AD treated mice compared to LPS challenged mice. Protein and EBD extravasation analysis showed a decrease in the LPS/AD treated mice compared to LPS alone.ConclusionsAD attenuated the LPS‐induced permeability increase as evidenced by decreased leakage of protein and in the BAL and EBD extravasation into the lung. In addition, AD also decreased lung inflammation measured by BAL neutrophil cell counts. Further studies into the AD‐mediated signaling mechanisms in protecting the EC barrier may help elucidate the molecular pathways involved in EC barrier regulation. This work was supported by NIHLBI grant HL 083327 (ADV) and MCG PSRP grant (NSU).
Vascular dysfunction in adult mice generated by assisted reproductive technologies
Authors: Rexhaj Emrush , Scherrer Urs , Sartori Claudio 
Published: June 2021

Environmental influences acting early in life may predispose to premature cardiovascular disease. Assisted reproductive technologies (ART) involve the manipulation of early embryos at a time when they may be particularly vulnerable to external disturbances. We hypothesized ART predisposes to vascular dysfunction later in life.We therefore assessed vascular function in vitro (mesenteric artery) and in vivo (blood pressure, carotid artery) in young adult (10 wks) ART and control mice.In ART mice endothelium‐dependent mesenteric‐artery vasodilation in vitro was markedly impaired (P<.001 vs. control). This endothelial dysfunction in vitro was associated with arterial hypertension in vivo (108±4 vs. 103±4 mmHg, X±SE, P=.02, ART vs. ctrl). Most interestingly, male ART offspring transmitted their vascular dysfunction to the next generation, suggesting an epigenetic mechanism. To test for this possibility, we examined the effects of the histone deacetylase inhibitor Butyrate (2 mg/kg/day, i.p. for 2 wks) to male offspring of ART. Butyrate normalized vascular function in these animals (P<.001 vs. ctrls) and prevented the transmission of this defect to the next generation (P<0.001 butyrate vs. vehicle). We demonstrate for the first time that ART induces premature systemic vascular dysfunction in mice by an epigenetic mechanism. We speculate that ART may induce a similar problem in humans.Grant Funding Source: Swiss National Science Foundation
Bone Marrow‐Derived Cells Stimulate Healing by Modulating Early Inflammatory Processes
Authors: Schatteman Gina C , Jiao Chunhua , Leymaster Nicholas , Timpe Josh , Dunnwald Martine 
Published: June 2021

Improvements in healing and vascular growth from acute exogenous bone marrow‐derived cell (BMDC) therapy are apparent by a few days after injury, suggesting that BMDCs modulate early inflammatory events. That MCP‐1 is essential for BMDC mediated healing supports this hypothesis. To examine BMDC impact on inflammatory processes and subsequent growth factor production, BMDCs from healthy (wt), obese diabetic (db) and monocyte chemoattractant protein‐1 (MCP‐1‐) knockout mice were injected into ischemic mouse hindlimbs. (BMDCs from C57Bl/6 but not db or MCP‐1‐ mice stimulate MCP‐1 production and promote limb healing.) Fewer immunolabeled monocytes (day 3) and neutrophils (day 1) were seen in ischemic limbs treated with BMDCs from db and MCP‐1‐ mice than those that received cells from wt mice. However, levels of six pro‐angiogenic growth factors measured by ELISA at days 1, 3, and 5 did not correlate with the extent of monocyte/neutrophil infiltration or healing. We observed a complex temporally regulated pattern of growth factor expression in ischemic muscle that differed depending on cell treatment, but at all time points for all factors differences were at most 2‐fold. Thus, BMDCs may stimulate healing by an immunomodulatory process that only modestly impacts pro‐angiogenic growth factor expression and that may not require their upregulation to induce vascular growth and healing.Support: NIH DK55965
Disambiguating Muscular Forces Effecting Hyoid Movement in Pharyngeal Phase of Deglutition
Authors: Pearson William G. , Zumwalt Ann 
Published: June 2021

IntroductionSuperior and anterior hyoid movements are important clinical events in the pharyngeal phase of swallowing. Fluoroscopy charts the movement of the bone but cannot assess soft tissue. Electromyography specifies muscle activation but not the structural effect of depolarization. This cross‐sectional study uses a cadaver model to generate the continuous data needed to establish an anatomical foundation for these movements.MethodsMeasurements to determine physiological cross‐sectional areas (PCSA) of swallowing muscles were taken from 7 formalin‐fixed cadavers. Cartesian attachment coordinates and PCSAs were used to calculate i and j unit force vectors where i and j represent anterior and superior movements, respectively. Three functional muscle groups were established for analysis of variance (ANOVA): mylohyoid and stylohyoid (MH‐SH), digastrics (DG), and geniohyoid (GH).ResultsANOVA with Tukey HSD showed a statistical difference in i unit force vectors (GH > DG [p < .01], GH > MH‐SH [p < .01], DG > MH‐SH [p < .05]) and j unit force vectors (MH‐SH > DG [p < .01], MH‐SH > GH [p < .01]).DiscussionThe GH is primarily responsible for the anterior excursion of the hyoid during swallowing while the MH‐SH elevates the hyoid. This is the first in a series of investigations to elucidate the anatomical substrate of pharyngeal deglutition to enable clinicians to better understand and treat dysphagia.Grant Funding Source: n/a
Migration and differentiation of epicardial cells stimulated by TGFβ1, TGFβ2, or BMP‐2 do not require the Type III Transforming Growth Factor β receptor
Authors: Austin Anita , Compton Leigh A , Love Joseph D , Sanchez Nora A , Brown Christopher B , Barnett Joey V 
Published: June 2021

Transforming Growth Factor β (TGFβ) Receptor III (TGFβR3) binds all three TGFβ ligands, inhibin, and Bone Morphogenic Protein‐2 (BMP‐2). Since TGFβ causes epicardial cell differentiation into smooth muscle in vitro we asked if Tgfbr3 null epicardial cells differentiate in response to TGFβ or BMP‐2. Wiltype and Tgfbr3−/− immortalized mouse epicardial cells (ED 11.5) were cultured in the presence or absence of ligands for 72 hours and scored by immunohistochemistry, QT‐PCR, or a reportor assay for Smooth Muscle 22 alpha (SM22α). Wildtype and Tgfbr3−/− cells lose epithelial character and undergo smooth muscle differentiation in response to 250 pM TGFβ1 or TGFβ2. Induction of SM22α in wildtype cells occurred with an EC50 of 12.5 pM. BMP‐2 (5 nM) induced the loss of Zonula Occludens‐1 (ZO‐1) but failed to induce the smooth muscle markers SM22α, smooth muscle α‐actin (SMαA) or calponin. Inhibition of activin receptor‐like kinase (ALK) 5 with 2.5 μM SB431542 blocked the effects of TGFβ1 and TGFβ2, but not BMP‐2. Pre‐ and co‐incubation of cells with 5 nM BMP‐2 did not block the ability of 250 pM TGFβ1 or TGFβ2 to induce smooth muscle markers. These data demonstrate that BMP2 induces epicardial cell motility without smooth muscle differentiation and that TGFβR3 is not required for epicardial cell responsiveness to TGFβ or BMP‐2.Funding: HL085708, NIGMS 5K12GM068543Grant Funding Source: NIH HL
Nerve and Vascular Regeneration in Bone Transport Osteogenesis
Authors: Malavia Veera , Kontogiorgos E , Elsalanty ME , Dechow PC , Opperman LA 
Published: June 2021

ObjectiveTo evaluate blood vessel and nerve formation in mandibular regenerate bone reconstructed by distraction osteogenesis (DO).MethodsIn 10 dogs, a 30–40mm mandibular defect was created. A bone transport reconstruction device was used to create regenerate across the gap, using standard DO criteria, followed by 6 week of consolidation. Three implants were placed on the regenerate and control sides. One group (n=5) was left to heal for 12 weeks and the other (n=5) for 18 weeks. After sacrifice, regenerate and control bone was prepared for histology and n=2–3 slides/group were analyzed. One examiner blinded to the experiment counted numbers of blood vessels and nerves.ResultsRegenerate bone had significantly more blood vessels than control bone. Increased vascularity of the regenerate appeared to be due to the formation of new small blood vessels. Healing time had no effect on the number of blood vessels in the regenerate. Nerve number increased from 12 to 18 weeks for both groups. In the control group the number of small nerves increased; the regenerate group showed an increase in small and large nerves.ConclusionThe increased vascularity of the regenerate relates to new bone regeneration. Increased innervation of regenerate appears due to nerve generation in new bone, while in controls nerve damage due to implant placement might increase small nerve sprouting.Grant Funding Source: Supported by grants DE017259 and DE15437 from NIDCR
Mechanism and regulation of RNA Polymerase II transcription
Authors: Hahn Steven 
Published: June 2021

Recruitment of the RNA polymerase II (Pol II) transcription machinery at promoters involves the coordinated action of transcription activators and coactivators that facilitate positioning of Pol II and the general transcription factors at a promoter. This preinitiation complex (PIC) is poised to undergo a conformational change into an active conformation (open complex) with the melted template DNA strand in the enzyme active site. To understand the recruitment and transcription initiation steps, we have solved the structure of an activator‐coactivator complex and used biochemical probes to model the architecture of the PIC containing the general factor TFIIF.The yeast activator Gcn4 contains tandem acidic activation domains that interact with the Mediator coactivator subunit Gal11/Med15. The central Gcn4 activation domain adopts a helical structure when bound to Gal11 with three hydrophobic residues contacting a small hydrophobic surface of Gal11 with micromolar affinity. Unlike other activator‐target structures, there are no observed electrostatic interactions to help determine Gcn4 orientation. This simple and versatile interface can explain how acidic activators interact with multiple targets.The general transcription factor TFIIF functions at several steps in transcription initiation including PIC formation and start site selection. We find that in the PIC, two structured TFIIF domains bind Pol II at separate locations far from the active site with the TFIIF dimerization domain on the Pol II lobe and the winged helix domain of the TFIIF small subunit Tfg2 above the Pol II protrusion. Anchoring of these two structured TFIIF domains at separate sites locates an essential and unstructured region of Tfg2 near the Pol II cleft where it is in a position to interact with flexible regions of Pol II and the general factor TFIIB to promote initiation and start site selection.
The effect of physiological concentrations of six hormones on the growth of breast and prostate cell lines treated with human serum
Authors: Esfahani Amin , Bashyam Balachandran , Kendall Cyril WC , Srichaikul Korbua , Archer Michael C , Jenkins David JA 
Published: June 2021

BackgroundThe majority of cell culture studies assess the effect of hormones on cancer cell growth using media supplemented with charcoal treated serum (CTS). Our objective was to determine the effect of various hormones on the growth of breast and prostate cancer cells incubated in untreated whole human serum (PHS).MethodsMCF‐7, MCF‐10A breast and LNCaP prostate cancer cell lines supplemented with PHS were treated with two physiological concentrations of six hormones (17β‐estradiol (E2), dehydroepiandosterone (DHEA), dihydrotestosterone (DHT), testosterone (T), insulin and glucagon). Cell viability was measured after 72 hours using the MTS assay.ResultsAll hormones stimulated growth of MCF‐7 cells (p<0.05). MCF‐10A cell growth was inhibited by DHEA, DHT and T (p<0.05), unaffected by E2 and glucagon, and stimulated by insulin (p<0.05). LNCaP cell growth was stimulated by the highest concentration of DHEA and DHT (p<0.05) and inhibited by the highest concentration of E2 (p<0.05). Insulin and T did not alter LNCaP growth. PHS lowered the magnitude of the hormonal effect by comparison to CTS.ConclusionsUnexpectedly, high concentrations of testosterone did not stimulate LNCaP cell growth and we observed for the first time that glucagon stimulates breast cancer cell growth. (Funding provided by Canada Research Chair discretionary funds)
Plasma hepcidin is a modest predictor of dietary iron bioavailability in humans, whereas oral iron loading, measured by stable‐isotope appearance curves, increases plasma hepcidin
Authors: Troesch Barbara , Biebinger Ralf , Egli Ines , Zeder Christophe , Hurrell Richard , Zimmermann Michael 
Published: June 2021

Plasma hepcidin appears to be a major regulator of iron absorption and homeostasis, but there are few data in humans.We aimed to see if circulating hepcidin predicted iron bioavailability and to measure the plasma hepcidin response to varying amounts of absorbed iron.In study 1, women (n = 98) with serum ferritin concentrations < 25 or > 40 μg/L were given stable isotope–labeled meals with ferrous sulfate (FeSO4), ferrous fumarate (FeC4H2O4), or ferric pyrophosphate (FePPi). Then, plasma hepcidin and iron absorption were measured. In study 2, iron‐sufficient men (n = 4) were given oral doses of 3.8 mg and 60 mg iron as labeled FeSO4. The stable isotope appearance and the plasma hepcidin curve were measured over 6 h.In study 1, plasma hepcidin and ferritin strongly correlated (r = 0.79, P < 0.001). Plasma hepcidin significantly, but modestly, predicted iron bioavailability from FeSO4 and FeC4H2O4 (r = 20.51 and 20.46, respectively; P < 0.0001) but not from FePPi (r = 20.30, P = 0.056). In study 2, the 3.8 mg dose increased circulating absorbed iron to 0.42 μmol/L but did not increase plasma hepcidin. The 60 mg dose increased mean circulating absorbed iron to 5.9 μmol/L and produced a ~30% increase in plasma hepcidin at 6 h (P < 0.01).Plasma hepcidin is only a modest predictor of dietary iron bioavailability. Oral iron loading increases circulating hepcidin.The ETHZ and DSM Nutritional Products financially supported this study.