bluuebunny/crossref_metadata_2025_split huggingface dataset:
The function of cAMP responsive element modulator (CREM) in PDGF induced proliferation of vascular smooth muscle cells
Authors: Seidl Matthias Dodo , Hildebrandt Iris , Klugstedt Christian , Nunes Frank , Endo Shogo , Kojima Nobuhiko , Schmitz Wilhelm , Müller Frank Ulrich 
Published: June 2021

The transcription factor CREM plays an important role in cAMP mediated gene expression. Here we want to clarify the role of CREM in vasculature particularly with regard to the regulation of VSMCs proliferation, using CREM (CKO) and CREM isoform ICER (IKO) deficient mice.CKO mice showed an increase of neointima formation associated with a higher proliferation rate of aortic VSMCs under platelet‐derived growth factor (PDGF) treatment. The PDGF alpha receptor (Pdgfra) promoter was inducible by cAMP and mRNA was upregulated in aortae and PDGF‐treated primary VSMCs of CKO mice. In untreated IKO‐VSMCs the proportion of proliferating cells was higher as compared to WT‐VSMCs, while no differences were observed under PDGF treatment. Induction of cAMP by forskolin reduced the proliferation rate of both IKO and WT‐VSMCs under PDGF treatment.Accordingly, ICER was linked to the elevated proliferation of VSMCs under non‐stimulated conditions, however, other CREM isoforms than ICER inhibit PDGF‐mediated proliferation of VSMCs possibly by modulation of cAMP‐dependent Pdgfra gene regulation. (supported by DFG)
Inhibition of Soluble Epoxide Hydrolase Augments Hypoxic Pulmonary Vasoconstriction and Improves Gas Exchange in Mice
Authors: Beloiartsev Arkadi , Ventocilla Christian , Winkler Jeffrey D. , Bloch Kenneth D. , Zapol Warren M. 
Published: June 2021

Recent studies report that cytochrome P‐450‐derived epoxyeicosatrienoic acids (EETs) increase pulmonary vascular tone. We hypothesized that inhibiting the metabolism of EETs by inhibition of soluble epoxide hydrolase (sEH) would augment hypoxic pulmonary vasoconstriction (HPV) and improve gas exchange.Mice were anesthetized, intubated, and ventilated at FIO2=1. Animals received an i.v. infusion of the sEH inhibitor, IK‐950, or vehicle 30 minutes prior to assessing HPV. After thoracotomy, pulmonary artery pressure (PAP) and left lung blood flow (QLPA) were measured before and during transient inferior vena cava occlusion. Left lung pulmonary vascular resistance (PVRL) was calculated from the slope of the PAP‐QLPA relationship. The pulmonary vasoconstrictor response to unilateral left lung hypoxia was estimated by comparing PVRL before and after left main stem bronchial occlusion (LMBO).Infusion of vehicle or IK‐950 did not change baseline hemodynamic parameters. LMBO increased PVRL, without changing PAP in both vehicle‐and IK‐950‐pretreated mice. Increase in PVRL during LMBO was greater in mice pretreated with IK‐950 than in those pretreated with vehicle (Table). PaO2 after LMBO was greater in mice pretreated with IK‐950 than in those pretreated with vehicle.Taken together, these results indicate that IK‐950 acts as a selective pulmonary vasoconstrictor of hypoxic lung regions, enhancing the perfusion of ventilated lung regions.
Regulation of cell motility by Na+/H+ exchanger NHE1: implications for cancer development
Authors: Pedersen Stine Falsig 
Published: June 2021

Essential roles of ion channels and transporters in regulation of cell motility have been discovered within the last decade. Here, I review recent evidence from our laboratory and others regarding the roles of the Na+/H+ exchanger NHE1 in cell motility, with particular focus on the implications for cancer metastasis. In many cell types, NHE1 localizes to the leading edge of migrating cells and regulates directional cell motility by mechanisms which include the formation of intra‐ and extracellular pH‐gradients and likely also direct protein‐protein interactions and local cell volume changes. In addition, NHE1 localizes strongly to invadopodia: actin‐rich structures assigned essential roles in invading cells. Here, NHE1 appears to be involved in both invadopodia formation and in their extracellular matrix‐degrading function. NHE1 is upregulated in a wide range of human cancers, and inhibition/knockdown of NHE1 attenuates metastasis in several cancer models. However, under some conditions, NHE1 inhibition/knockdown increases adhesiveness and motility, suggesting that the specific role of NHE1 is context‐dependent. In conclusion, NHE1 plays important roles in controlling cell motility. However, to exploit the obvious potential of interfering with NHE1 function to treat cancer metastasis, greater mechanistic understanding of the mechanisms is needed.Funding: Danish Cancer Society, Danish Research Council
Mechanisms of interferon gamma‐induced suppression of aquaporin 1 in murine intestinal epithelium
Authors: Dicay Michael , Ronaghan Natalie , Peplowski Michael , Carati Colin , MacNaughton Wallace K. 
Published: June 2021

Chronic diseases like IBD are characterized by high levels of IFNγ and abnormal intestinal transepithelial fluid flux. The water channel protein Aquaporin 1 (AQP1) is widely expressed on intestinal epithelial cells with the primary purpose of regulating transmembrane water flux. To investigate the deficiencies in water transport associated with IBD, we sought to determine the cellular signaling mechanisms by which IFNγ modulates AQP1 expression in the mouse intestinal epithelium.CMT93 cells treated with IFNγ significantly decreased constitutive AQP1 levels detected by immunofluorescence. Pre‐treatment with either the JAK1 inhibitor or STAT3 siRNA, prior to IFNγ administration resulted in the amelioration of the IFNγ‐induced suppression of AQP1 protein expression. Conversely, IRF‐2 siRNA pre‐treatment further decreased AQP1 protein levels following IFNγ treatment.Inflammatory cytokines present during IBD are able to influence AQP1 levels and may contribute to the water transport deficiencies associated with these disorders. In this study, the results suggest that decreased epithelial AQP1 expression exerted by IFNγ in CMT93 cells is regulated by JAK1 and STAT3. Of note, IRF‐2 which is normally considered to be a negative regulator of IFNγ signaling, acted in a positive regulatory fashion by further decreasing AQP1 protein signal.Source of funding: Crohn's & Colitis Foundation of Canada
Sex differences in the effects of β‐estradiol on ENaC current in cell culture
Authors: Mitzelfelt Jeremiah D , Greenlee Megan M , Eaton Douglas C 
Published: June 2021

Using cell‐attached patch clamp, we have previously shown that β‐estradiol (E2) activates epithelial sodium channels (ENaC) in alveolar cells. In an attempt to develop a high throughput electrophysiological assay to test the effect of estradiol (E2) and estrogen receptor agonists/antagonists on ENaC, we examined the effect of E2 on amiloride‐sensitive transepithelial current (TEC) in two kidney cell lines (2F3 and mpkccd) with known ENaC activity. E2 had no effect on amiloride sensitive current in either of these cell lines. The lack of an E2 response in the 2F3 and mpkccd cells may result from differences in tissue origin (lung vs. kidney) or sex of the donor animal (male for 2F3 and mpkccd cells, female for L2 cells). To address this question, we measured TEC in MDCK cells, a kidney cell line from a female dog. E2 increased amiloride‐sensitive TEC in MDCK cells. These data suggest that E2 increases ENaC current in females only and may play a role in sex differences in the rate and severity of diseases involving ENaC.Funding: NIH R37DK037963, K12GM000680 and T32HL076118
The interactive effects of K+ and Cl− on force generation in skeletal muscles: impact at the onset of exercise
Authors: Higgins Amanda Marie , Renaud Jean‐Marc 
Published: June 2021

It is now established that interstitial [K+] ([K+]int) increases to 12–14 mM even during moderate exercise. Although it is known that such increases in [K+]int contribute to the decrease in force during fatigue, recent studies suggest that at the onset of exercise small increases in [K+]int actually potentiates force and K+‐induced force depression is prevented by decreases in Cl− conductance (GCl). However, most studies were carried out at temperatures ranging from 25°–30°C or under very specific stimulation frequencies. The objective of this study was to document how the [K+]int – force relationship is modulated at 37°C, at different frequencies and under different GCl in order to better understand how muscle performance can be maximized at the onset of muscle activity.At a stimulation frequency allowing for maximal tetanic force, soleus muscle started to lose force at 10 and was completely lost by 13. EDL muscles were less sensitive to [K+]int, such that loss of force started at 13 and was completely lost by 15mM. The critical [K+]int required for tetanic force depression to start at 37°C is much higher than the critical [K+]int reported at lower temperatures. Twitch force was potentiated by 80–100% as [K+]int was elevated from 8–11 for soleus and from 8–13.5mM in EDL, while further increases in [K+]int caused a gradual decline in twitch force. Potentiation up to 150% can also occur at frequencies of 1–30Hz in soleus, and 1–100Hz for EDL. The major effect of reducing GCl was an increase in the critical [K+]int that caused a depression of force.
Resistance Training and CLA/n‐3 Administration Improve Myofiber Size and Myogenic Capacity in High Fat Diet‐Fed Mice
Authors: Lee Sang‐Rok , Jo Edward , Khamoui Andy V , Park Bong‐Sup , Zourdos Michael C , Panton Lynn B , Ormsbee Michael J , Kim Jeong‐Su 
Published: June 2021

Conjugated linoleic acid (CLA) and omega‐3 fatty acids (n‐3) have received great attention due to their health enhancing benefits. However, the morphogenetic capacity of skeletal muscle during high fat diet (HFD)‐induced obesity and the efficacy of CLA/n‐3 remain to be established. Therefore, we investigated the effects of 20 wks of CLA/n‐3 administration and resistance exercise (RE) on muscle cross sectional area (CSA) and myogenic capacity in HFD‐fed mice. Once sacrificing eight C57BL/6 male mice (age=9 mo), the remaining animals were randomly assigned to five experimental groups (n=10/group): 1) normal diet (C), 2) high fat diet (H), 3) HFD + RE (HE), 4) HFD + CLA/n‐3 (HCN), or 5) HFD + RE + CLA/n‐3 (HECN). Progressive RE was administered on a ladder climbing device 3d/wk for 20 wks. The supplement consisted of 1% CLA and 1% n‐3. Immunohistochemical techniques were employed to evaluate myofiber CSA and the numbers of satellite cell (SC) and myonuclei. Data were analyzed with one‐way ANOVA and significance was set at p<0.05. Muscle CSA significantly reduced in H (−23%) and HCN (−19%) from baseline while maintained in C, HE, and HECN. Only H exhibited a significant decrease in the numbers of SC (−17%) and myonuclei (−19%) from baseline with no change in C, HE, HCN, and HECN. Our findings indicate that 20‐wk HFD induced myofiber atrophy and impaired myogenic capacity. These impairments were improved partially by RE and/or CLA/n‐3 administration.Study partly supported by Sekwang Inc., Vital Pharmaceuticals, and Ocean Nutrition
High fat diet decreases glucose‐dependent modulation of 5‐HT responses in gastrointestinal vagal afferent neurons
Authors: Troy Amanda E , Browning Kirsteen N 
Published: June 2021

5‐hydroxytryptamine (5‐HT) release from intestinal enteroendocrine cells activates gastrointestinal (GI) vagal afferent neurons inducing a vagally‐mediated gastric relaxation and satiation. Since glucose modulates the response of GI vagal afferent neurons to 5‐HT, we hypothesized that exposure to a high fat diet (HFD) may affect these actions of glucose.Rats were fed control or HFD (18% or 60% kcal from fat, respectively) from 4 weeks of age for 8 weeks. Electrophysiological recordings were made from acutely dissociated GI vagal afferent neurons and immunocytochemical studies assessed the neuronal distribution of 5‐HT3 receptors.5‐HT induced an inward current which was sensitive to glucose in the majority (12/13) of control GI vagal afferent neurons. The proportion of 5‐HT‐sensitive GI vagal afferent neurons was unaffected by HFD (5/6 & 5/6 neurons after 1 & 8 weeks respectively, P>;0.05 vs control). HFD attenuated glucose modulation of the 5‐HT response; after 1 week, glucose modulated the 5‐HT response in only 1/5 HFD neurons (151, 183 and 354pA in response to 2.5, 5, and 10mM glucose) while after 8 weeks, 0/5 HFD neurons were affected by glucose. Furthermore, after HFD glucose was unable to alter the proportion of membrane‐associated 5‐HT3 receptors (28±0.8% at 2.5mM to 29±0.7% at 20mM glucose) in contrast to previous control studies (24±1.8% at 2.5mM to 37±2.6% at 20mM glucose).These data suggest that, while exposure to HFD does not affect the responsiveness of GI vagal afferent neurons to 5‐HT, it diminishes the ability of glucose to regulate 5‐HT responses. This suggests that glucose‐dependent vagal afferent signaling is compromised by relatively short periods of exposure to HFD well in advance of the development of obesity.Supported by NIH DK078364
Inhibition of RhoA/Rho Kinase Pathway and Contraction by Endogenous and Exogenous Hydrogen Sulfide in Gastrointestinal Smooth Muscle
Authors: Nalli Ancy D , Rajagopal Senthilkumar , Mahavadi Sunila , Grider John R , Murthy Karnam S 
Published: June 2021

Inhibitory neurotransmitters, chiefly nitric oxide and vasoactive intestinal peptide, cause MLC20 dephosphorylation and smooth muscle relaxation via inhibition of MLCK and activation of MLCP. H2S produced by commensal bacteria in the colon or synthesized from L‐cysteine via cystathionine‐γ‐lyase (CSE) and cystathionine‐β‐synthase (CBS) regulates smooth muscle tone.AimTo examine the expression of CSE and CBS in gastrointestinal smooth muscle and to elucidate the molecular mechanism of H2S‐induced muscle relaxation.MethodsExpression of CSE and CBS was analyzed by RT‐PCR and western blot. The effect of H2S on carbachol‐induced muscle contraction and Rho kinase activity was examined using an endogenous activator (L‐cysteine) of CSE and CBS and an exogenous H2S donor (NaHS).ResultsExpression of CSE, but not CBS was detected in smooth muscle cells of stomach and colon from mouse, rabbit and human. Carbachol‐induced contraction in muscle strips and muscle cells, and increase in Rho kinase activity were inhibited by L‐cysteine or NaHS in a concentration‐dependent manner (1 to 100 mM). Glibenclamide, an inhibitor of KATP channels and a known target of H2S, had no effect on the inhibition of contraction by H2S.ConclusionBoth endogenous and exogenous H2S induce muscle relaxation, and the mechanism is via the inhibition of RhoA/Rho kinase activity leading to stimulation of MLCP activity and muscle relaxation.
Pro‐Resolving Mediator Production by Human Phagocytes and their Transcellular Biosynthesis with Microparticles in Inflammation‐Resolution
Authors: Dalli Jesmond , Serhan Charles 
Published: June 2021

Phagocytes are central in orchestrating the acute host response during inflammation and its timely resolution. Using lipid mediator (LM) metabololipidomcs, we assessed LM levels in neutrophils (PMN), apoptotic PMN and macrophages. During efferocytosis, macrophages upregulate the biosynthesis of specialized pro‐resolving mediators (SPM), including resolvin (Rv) D1 and RvD2, that were further elevated by PMN microparticles (MP). Using deuterium labeled precursors we found that both apoptotic PMN and MP donated precursors to macrophages that were utilized for transcellular SPM biosynthesis. Fresh PMN from peripheral blood with zymosan gave predominantly leukotriene B4, whereas apoptotic PMN displayed both elevated prostaglandin E2 and lipoxin (LX) B4. Lineage differentiated macrophages showed distinct LM profiles where M2 macrophages gave higher SPM including maresin 1 and lower prostaglandins then M1. These profiles were regulated during efferocytosis where M1 cells gave increased SPM including LXA4 while overall LM biosynthesis was reduced in M2. Together these findings establish the LM signatures of human phagocytes and their regulation during distinct stages of acute inflammation‐resolution.This work was supported by the NIH (grants GM038765 and GM095467).
Sphingosine‐1 phosphate receptor‐1 desensitization mediated by isoforms of protein kinase C: receptor phosphorylation
Authors: Morquecho‐León Marco Antonio , Bazúa‐Valenti Silvana , Romero‐Ávila María Teresa , García‐Sáinz Jesús Adolfo 
Published: June 2021

Sphingosine‐1 phosphate (S1P) is important in the regulation of angiogenesis, vascular permeability and stability, development of new blood vessels, vascular maturation, cardiac development, immunity and cellular mobility routing. A deficiency in the regulation of sphingosine phosphate receptor type 1 (S1PR1) can cause health disorders, such as development of autoimmune diseases or formation of new vasculature in solid tumors.Although it is known that PKC phosphorylates and possibly regulates S1PR1, we don't know which PKC isoforms are involved, as well as target sites. In the present investigation we have found that S1PR1 is phosphorylated by the action of 12‐O‐tetradecanoylphorbol‐13‐acetate, a direct activator of PKCs, and that this phosphorylation does not occur when using a general inhibitor of PKCs bisindolylmaleimide and decreases by approximately 90% when using a specific inhibitor for PKCα (Gö6976).Using dominant negative isoforms of PKC α and βII we found that receptor phosphorylation mediated by TPA was prevented in approximately 50% and 40% respectively. Site directed mutagenesis showed that the mutant receptor ‐changes serines 351, 353, 355, 358 and 359 to alanines‐(S1PR1–5A) phosphorylation decrease nearly to basal levels in both S1P and TPA stimulations.Research sponsored by DGAPA IN200812 and CONACyT 177556
Effect of Hydrogen Sulfide on Isolated Bovine Ocular Smooth Muscle
Authors: Okpobiri Anita Chinwe , Njie‐Mbye Ya Fatou , Robinson Jenaye , Chitnis Madhura , Opere Catherine , Ohia Sunny 
Published: June 2021

PurposeTo investigate the pharmacological effects of the amino acid, L‐cysteine, a substrate for hydrogen sulfide (H2S) production, on isolated pre‐contracted bovine iris‐ciliary muscle. Furthermore, we examined the mechanism of action of L‐cysteine in eliciting relaxations of this tissue.MethodsBovine iris‐ciliary muscle strips were mounted in organ baths containing oxygenated Krebs buffer (pH 7.4, 37□ C). Changes in isometric tension were recorded and analyzed via Force‐displacement transducers. Effects of L‐cysteine on carbachol‐induced tone were studied in the presence of enzyme inhibitors for H2S biosynthetic pathway (AOA; cystathionine β‐synthase inhibitor) and prostanoids (flurbiprofen; cyclo‐oxygenase (COX) inhibitor).ResultsL‐cysteine (0.01 nM–100 μM) evoked a dose‐related relaxation of carbachol‐induced tone in bovine iris‐ciliary muscle, reaching a maximum inhibition of 88% at 10 μM (with an IC50 of 2 nM). Relaxations elicited by L‐cysteine were unaffected by pretreatment of tissues with flurbiprofen (3 μM). The inhibitor of cystathionine β‐synthase, AOA (10 μM) blocked only relaxations caused by high concentrations of L‐cysteine (>; 500 nM).ConclusionsL‐cysteine can relax pre‐contracted bovine iris‐ciliary muscle, and this effect is dependent on endogenous production of H2S. Furthermore, prostanoids are not involved in the inhibitory action of L‐cysteine in this smooth muscle.
Heterogeneity of cardiac myocyte contractile properties during long‐term stimulation; substrate effects
Authors: Barton Gregory , Diffee Gary 
Published: June 2021

Substrate utilization in the heart is well documented and favors fatty acid oxidation in normal healthy hearts. Most studies looking at metabolic effects on contractile properties have been done in the whole heart and little information is known about the cellular contractile response to different substrates. To determine potential substrate effects on contractile properties in isolated myocytes, we measured percent shortening and rate of shortening at time 0 (T0) and after 10 minutes (T10) of continuous stimulation at 1 Hz in myocytes isolated from healthy hearts and bathed in either 11mM glucose (G) or 0.1mM palmitate (P) during contractile measurements. We determined not only mean shortening but the distribution of shortening properties among cells in order to determine how much heterogeneity there was among myocytes. Mean shortening was significantly greater in P (12.2 %) than in G (9.8%). Although the mean shortening significantly decreased in both groups at T10 compared to T0, analysis of the distribution showed nearly all cells decreased % shortening at T10 in P, while the cells in G demonstrated a more heterogeneous response at T10, with one‐third of the cells showing an increased shortening. These results suggest substrate does influence shortening properties, and distributional analysis reveals significant heterogeneity among cells in their response to different substrates.Supported by NIH AG 030423
The Effects of Palmitic Acid and Oleic Acid on Macrophage Gene Expression
Authors: Reyes Ariel Delos , Camell Christina , Smith C. Wayne , Rumbaut Rolando E. 
Published: June 2021

Macrophages are critical in regulating inflammation and can be polarized to promote or inhibit inflammation. They have crucial roles in the clearance of excess fatty‐acids; however, their response to individual fatty‐acids are unclear. We hypothesized that bone marrow derived macrophages (BMDMs) treated with oleic acid will have increased anti‐inflammatory gene expression, and BMDM treated with palmitic acid will have increased pro‐inflammatory gene expression. We tested this hypothesis by culturing murine BMDM in the presence of oleic or palmitic acid and analyzing gene expression of markers for pro‐inflammatory (TNFα, CD11c and iNOS) and anti‐inflammatory macrophages (Arg1, MGL1, CD206, Chi3L3 and RETNLA). Palmitic acid increased TNFα expression though decreased CD11c and iNOS expression, whereas oleic acid increased Arg1 and MGL1 expression in BMDMs. We found no change in other genes examined. Additional macrophage markers and samples would need to be analyzed to clearly identify if fatty‐acids can polarize BMDMs; however, our data suggests that individual fatty‐acids can regulate expression of some pro‐ and anti‐inflammatory macrophage markers.Support: APS Frontiers in Physiology Fellowship; NRSA F‐31‐DK084841‐04; USDA/ARS CHRC 6250–51000‐055
PGC‐1α deletion accelerates angiotensin II induced endothelial dysfunction by increasing mitochondrial oxidative stress and vascular aging
Authors: Schulz Eberhard , Kröller‐Schön Swenja , Jansen Thomas , Schüler Andrea , Oelze Matthias , Wenzel Philip , Hausding Michael , Kerakrodi Jasmin Ghaemi , Daiber Andreas , Münzel Thomas 
Published: June 2021

ObjectivePeroxisome proliferator coactivator 1α (PGC‐1α) is an important mediator of mitochondrial biogenesis and function. Since dysfunctional mitochondria might be involved in the pathogenesis of vascular disease, the current study was designed to investigate the effects of in vivo PGC‐1α deficiency during chronic angiotensin II (ATII) treatment.Methods and ResultsATII infusion at subpressor dose (0.1mg/kg/d) resulted in mild endothelial dysfunction in wildtype mice, which was significantly aggravated in PGC‐1α knockout mice. In parallel, mitochondrial oxidative stress was increased in aortic rings from ATII‐treated PGC‐1α knockout mice while no change in NO production was observed. The increase in mitochondrial ROS was associated with premature vascular aging (p16INK4 and Chk‐2 expression) and enhanced activity of the pro‐apoptotic JNK signaling pathway. In vivo treatment with the mitochondrial targeted antioxidant mitoTEMPO corrected endothelial dysfunction in ATII‐treated PGC‐1α knockout but not in wildytpe mice, suggesting a crucial role of mitochondrial ROS in this process.ConclusionsPGC‐1α deletion impairs endothelial function during chronic angiotensin II infusion by increasing mitochondrial ROS production, which results in premature vascular aging and apoptosis.