bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversal of Stem Cell Mobilopathy and Enhanced Vascular Repair by Angiotensin‐(1‐7) in Diabetes
Authors: Vasam Goutham , Jarajapu Yagna 
Published: November 2023

Bone marrow stem/progenitor cells (BMSPCs) are mobilized in response to ischemic injury. BMSPCs accelerate vascular repair by re‐endothelialization and revascularization of ischemic areas. Long‐term diabetes causes impairment of mobilization, a.k.a. stem cell mobilopathy, which has now been considered as a major contributing factor for the development of macro and microvascular complications and end‐organ damage. This study evaluated the beneficial effects of Angiotensin (Ang)‐(1‐7), a member of the protective axis of renin angiotensin system, in diabetic stem cell mobilopathy and ischemic vascular repair. Control or streptozotocin (STZ)‐induced type 1 diabetic mice, and type 2 diabetic db/db mice and their lean‐control mice were administered with Ang‐(1‐7) (1 μg/kg/min) or normal saline using subcutaneous osmotic pumps for four weeks. Circulating BMSPCs were enumerated before and after the treatment by flow cytometric enumeration of lineage‐negative (Lin−), Sca‐1 and c‐Kit (LSK) or by Colony Forming Unit (CFU) assay. Hind‐limb ischemia (HLI) was induced by femoral artery ligation; mobilized BMSPCs and blood flow recovery were determined over a period of 10 days post‐HLI by using Laser Doppler blood flow imaging system. Vascular repair was assessed by quantification of capillary density in the ischemic skeletal muscle by immunohistochemistry. The number of circulating BMSPCs are decreased (P<0.01, n=8) in STZ‐ and db/db mice compared to their respective controls. Circulating BMSPCs were increased in control mice in response to ischemic injury, that showed peak response at day‐2 following the injury and returned to normal by day 10 (n=6–8). Blood flow was recovered to 90% of contralateral non‐ischemic limb by day 10. Ischemia‐induced mobilization of BMSPCs was impaired in both models in response to ischemic injury (P<0.001 vs respective controls, n=6–8). This dysfunction was associated with delayed and decreased blood flow recovery (P<0.001, n=6–8), and impaired neovascularization (P<0.001, n=6–8) of ischemic areas. Ang‐(1‐7) treatment increased/normalized the circulating LSK cells, and restored their mobilization following ischemic injury in STZ‐ and db/db mice (n=6–8). Blood flow recovery was accelerated and normalized with enhanced neovascularization of ischemic areas in both models of diabetes by Ang‐(1‐7) compared to the untreated (n=6–8). To our surprise, this protective response was associated with increased Rho‐kinase activity, specifically in the BMSPCs but not in the peripheral cardiovascular tissues (n=5). This study provides compelling evidence for the reversal of diabetic stem cell mobilopathy, and enhanced ischemic vascular repair in diabetes by Ang‐(1‐7) treatment.Support or Funding InformationThis work is partly supported by American Heart Association, and the Core Biology Facility at North Dakota State University that was made possible by NIH‐NIGMS (P30 GM103332‐01).
Salivary Peptides Regulate Intracellular Calcium in Rat Pancreatic Beta Cells
Authors: Edwards Lincoln P , Fakhouri Walid D , Ardestani Pegah Memar , Zarezadeh Hossein 
Published: November 2023

ObjectivesProline Rich Proteins (PRPs), secreted by parotid gland, have a variety of functions including anti‐caries and anti‐bacterial properties, but less is known about their actions outside the oral cavity. One of these proteins, called Parotid Hormone (PH) in Sus scrofa, is believed to play a significant role in the maintenance of healthy dentin and have effects on other organs including pancreas by having regulatory effects on maintaining the sensitivity of beta cells to circulating glucose. Basic Salivary Proline Rich Protein 2 and 3 (PRB2 & PRB3), in human, have the highest sequence homology with porcine Parotid Hormone. Changes in cytosolic calcium ion concentration constitute an important element of signal transduction that may lead to insulin release. We hypothesized that PH, PRB2 and PRB3 are involved in insulin stimulation by regulating the intracellular calcium ion levels in pancreatic beta cells.MethodsCultured RIN‐m beta cells from Rattus Norvegicus were used as an in vitro model for measuring intra‐cellular calcium levels using the fluorescent dye Fura2‐AM. Cells in calcium‐rich or calcium‐free medium were treated with PH (34nmoles/200 μL), PRB2 (11nmoles/200μL) or PRB3 (11nmoles/200μL). In some experiments cells were pretreated with the L‐type calcium channel blocker diltiazem (10μM) or with thapsigargin (2μM) to deplete internal calcium stores, before treatment with the peptides.ResultsPH, PRB2 and PRB3 increased intracellular calcium levels in cultured beta cells by 3‐, 10‐ and 3‐fold respectively. In calcium‐free medium, no change was observed in intracellular calcium level after treatment with PH or PRB2; however treatment with PRB3 caused an increase in intracellular calcium level. Interestingly, calcium uptake by cells following PH and PRB2 treatment was partially blocked by diltiazem (10μM), whereas thapsigargin (2μM) treatment blocked the response caused by PRB3.ConclusionSalivary peptides PH, PRB2 and PRB3 show differential regulation of intracellular calcium in RIN‐m beta cells. Our data indicates that PH and PRB2 regulate an influx of external calcium partially through L‐type calcium channels, while PRB3 potentially regulates an increase of calcium from internal stores. In summary, our results suggest that PH, PRB2 and PRB3 may have regulatory functions beyond those that have been described in the literature, and may play a role in a parotid‐pancreatic axis.Support or Funding InformationDepartmental funding from the Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center at Houston, School of Dentistry.
α4‐selective GABAA Receptor Positive Allosteric Modulator Attenuates The “Asthma‐Like Phenotype” In A Murine Asthma Model
Authors: FORKUO GLORIA , Nieman Amanda , Yu Olivia , Guthrie Margaret , Yuan Nina , Kodali Revathi , Jahan Rajwana , Stephen Michael , Poe Michael , Hartzler Benjamin , Emala Charles , Cook James , Stafford Douglas , Arnold Leggy 
Published: November 2023

Asthma is a chronic inflammatory disease of the airways characterized by inflammation, mucous metaplasia and airway hyperresponsiveness. The chronic use of current treatment options is associated with adverse side effects, which warrants the development of new asthma therapies. An emerging new target to treat asthma is the GABAA receptor, which is a heteropentameric ligand‐gated chloride channel consisting of combinations of 19 different subunits (α1–6, β1–3, γ1–3, δ, ɛ, π, θ, ρ1–3). Exhaustively studied in the brain, GABAA receptors have lately been linked to inflammation, mucous production and airway hyperresponsiveness. We hypothesize that compounds with specificity towards a particular GABAA receptor assembly act tissue‐specifically and exhibit a well defined pharmacological profile. In this study, we determined the expression of GABAA receptor subunits in mouse lungs and the effects of a novel α4 subtype‐selective GABAAR modulator, XHE‐III‐74EE and its metabolite XHE‐III‐74A (has α4 selectivity and weak α5 selectivity) in an ovalbumin sensitized and challenged (Ova S/C) murine model of asthma. We observed that, chronic treatment with XHE‐III‐74EE but not XHE‐III‐74A significantly reduced airway hyperresponsiveness in Ova S/C mice. In addition, acute treatment with XHE‐III‐74A but not XHE‐III‐74EE decreased airway eosinophilia. Our results support the hypothesis that airway hyper‐responsiveness and inflammation can be targeted with α4/α5 subtype‐selective GABAAR modulators.Support or Funding InformationNational Institute of Neurological Disorders and Stroke [R01NS076517], National Institute of Mental Health [R01MH096463], National Heart, Lung and Blood Institute [R01HL118561], University of Wisconsin Milwaukee, UWM Research Foundation (Catalyst Grant), UWM Department of Chemistry and Biochemistry, and UWM Graduate School (RGI Grant), Milwaukee Institute for Drug Discovery
Therapeutic Potentials of Small‐Molecule Inhibitors Targeting Exchange Protein Activated by cAMP (EPAC)
Authors: Cheng Xiaodong , Zhu Yingmin , Mei Fang 
Published: November 2023

The pleotropic second messenger cAMP is an important stress signal that regulates a multitude of physiological functions under normal and diseased conditions. The major cellular effects of cAMP are transduced by two ubiquitously expressed intracellular cAMP receptors, protein kinase A (PKA) and exchange protein directly activated by cAMP (EPAC) in human. Using genetically engineered EPAC knockout mouse models, we have demonstrated that EPAC proteins play important roles in the development of major human diseases, including obesity, cancer and chronic pain etc. Furthermore, we have developed first‐in‐class EPAC specific inhibitors with favorable in vivo pharmacological and toxicological profiles. Applications of EPAC inhibitors in various animal disease models recapitulate the genetic phenotypes of EPAC knockout mice. These Studies validate the therapeutic potentials of small molecule EPAC specific inhibitors.Support or Funding InformationResearch is supported by grants from the National Institute Health (GM061770, GM106218 and AI111464).
Antihiperglycemic Effect of 5‐HT2 Receptor Stimulation Induced by indorenate, a serotonin analog
Authors: Hong Enrique , de Lourdes Medina Juana María , Silva‐Arzave Abigail 
Published: November 2023

The role of 5‐Hydroxytryptamine in the regulation of glycemia has been a controversial item for some time, however, there are recent findings suggesting that 5‐HT1A receptor stimulation increases the glycemia, while 5‐HT2 receptors do the opposite. Therefore, we decided to investigate the effect of indorenate, a central antihypertensive agent exerting this action by 5‐HT1A central receptor stimulation, but also possessing a 5‐HT2 peripheral receptor stimulation. Since less than 1 % of the oral administered dose penetrates into the CNS, most of the compound could stimulate the 5‐HT2 peripheral receptors leading to an antihyperglycemic effect. The oral dose of glucose (2g/kg) to fasted Wistar rats was followed by a hyperglycemia that was maximal one hr later, this effect was suppressed by the previous administration of an oral dose of 10 mg/kg of indorenate, however, metformin at an oral dose of 300 mg/kg only produce a slight, but significant decrease in hyperglycemia. Pelanserin, a 5‐HT2 antagonist, blocked the effect of indorenate, but WAY 100635, a 5HT‐1A agonist, did not. Indorenate also increase the glucose velocity needed to maintain blood glucose levels constant in an euglycemic insulin clamp in anesthetized Wistar rats. The present data suggest that indorenate may have a potential therapeutic usefulness in both, metabolic syndrome and in type2 diabetes.Support or Funding InformationAuthors are indebt to the SECITIDF for its support.
The Role of O‐GlcNAcylation in Regulating Mitochondrial Function in Cardiomyocytes
Authors: Wright JaLessa Nicole , Kramer Philip , Benavides Gloria , Johnson Michelle S. , Zhang Jianhua , Darley‐Usmar Victor , Chatham John 
Published: November 2023

The post‐translational modification of proteins by O‐linked‐N‐acetylglucosamine (O‐GlcNAc) is elevated in diabetes, and has been implicated in the adverse effects of diabetes on the heart including impaired mitochondrial function. Several studies have reported that the adverse effects of hyperglycemia on mitochondrial function are mediated via O‐GlcNAcylation of specific mitochondrial proteins such as NDUFA9 of complex I, complex III subunits core 1 and 2, as well as mitochondrial DNA‐encoded subunit I of complex IV. Moreover, a recent O‐GlcNAc profiling study revealed that numerous mitochondrial proteins were O‐GlcNAcylated, many of which are associated with oxidative phosphorylation i.e., NDUFS1 and ATP5A1. Conversely, it has also been reported that increasing O‐GlcNAc levels with thiamet‐G, a highly selective inhibitor for OGA, which catalyzes the removal of O‐GlcNAc from proteins, had no effect on mitochondrial function. Therefore the goal of this study was to better understand the effects of short‐term increases in O‐GlcNAcylation on mitochondrial function. AC16 cells, an immortalized human cardiac cell line, were treated with thiamet‐G (0.1, 1, 3 and 5 μM) to increase O‐GlcNAc for 1, 2, 4 and 6 h, followed by quantitative assessment of mitochondria bioenergetics using the Seahorse Extracellular Flux Analyzer. In a second series of experiments a 2 h recovery period, following thiamet‐G was introduced prior to measurement of mitochondrial bioenergetics. We found that a 2 h treatment with 3 μM thiamet‐G significantly increased maximal oxygen consumption rates (OCR), from a rate of 14 to 20 pmol/min/μg protein regardless of the duration of treatment. Surprisingly, after a 2 h recovery period there was an approximately 2‐fold decrease in maximal OCR and reserve capacity in untreated cells, while 3μM thiamet‐G doubled OCR to an average of 15 pmol/min/μg protein. In addition to increasing OCR; 3μM thiamet‐G also increased extracellular acidification (ECAR) rates. Thus, augmentation of O‐GlcNAcylation in AC16 cells with thiamet‐G stimulates both OCR and ECAR consistent with increased oxidative and glycolytic metabolism. Interestingly however, at 5μM thiamet‐G both OCR and ECAR were reduced compared to 3μM. In conclusion increasing O‐GlcNAc via thiamet‐G clearly influences both mitochondrial and glycolytic metabolism, suggesting that there is a subtle interaction between O‐GlcNAcylation and cellular metabolism. Future studies will investigate the mechanism(s) underlying the metabolic switch induced by increasing O‐GlcNAc levels as well as determine how this contributes to the response of mitochondria to cellular stress.I would like to thank the members of the Chatham and Darley‐Usmar labs for their assistance and support with this project.Support or Funding InformationThis work is supported by NIH grant 5T32HL007918‐17, HL101192 and UAB School of Medicine Multi‐Investigator Pilot Grant
CaMKIId As a Nodal Mediator of Insulin Signaling and Adrenergic Signaling in Cardiomyocytes – a Signaling Network Map Profiling by Quantitative Phospho‐proteomics
Authors: Dewan Sukriti , Campos Alex , Wu Shuangding , Stowe Jennifer , Wolf Alex , Bers Donald M , Brill Laurence M , Brown Joan H , McCulloch Andrew 
Published: November 2023

BackgroundCalcium and calmodulin mediated protein kinase II (CaMKIId) plays a key role in regulating cardiac physiology. Upregulated expression and activation of CaMKIId is reported in HF. While cardiac specific over‐expression of CaMKIIdc isoform leads to progressive HF in mice, cardiac specific knockout (KO) of CaMKIId isoform develop hypertrophy but do not progress into end‐stage HF. To elucidate the exact role of CaMKIId as a cardioprotective target, it is pertinent to investigate the signaling mechanisms altered by CaMKIId targets and study the pleiotropic effects of these interactions.AimThe purpose of this study is to identify novel CaMKIId signaling targets and interactions thereof, using a sensitive, wide‐range and quantitative, mass spectrometry‐based phosphoproteomics approach in acutely stressed isolated cardiomyocytes.MethodsTo identify putative downstream CaMKIId targets, mice were divided into two groups ‐ CaMKIId KO and control group. Adult cardiomyocytes were freshly isolated by the Langendorff method. A total of 3 biological replicates (pooled from 12 animals) were used per genotype for the present study. Isolated cardiomyocytes were treated with 10uM of isoproterenol for 5 minutes to induce CaMKIId activation via beta‐adrenergic stimulation. Enriched phosphopeptides from CaMKIId KO and control mice samples were differentially quantified high‐resolution liquid chromatography mass spectrometry (LC‐MS/MS). All mass spectra from Phospho‐ and Total samples were analyzed with MaxQuant software. For pathway analysis, proteins with differentially regulated phospho‐sites were keyed in ClueGo (Cytoscape plug‐in) and Ingenuity Pathway Analysis (IPA); and the resulting enriched signaling pathways were functionally grouped by parsing through KEGG, Reactome and Wiki Signaling Pathway databases. These functional signaling groups were then visualized as a comprehensive interconnected network. An interaction map of all enriched signaling pathways with differentially regulated phospho‐proteins was generated. Flourimetric glucose uptake assays and western blots were used to quantify insulin resistance under stress conditions and mechanisms thereof.ResultsKey network hubs and pathways that were predicted to be involved in CaMKIId signaling are cardiac contraction, cAMP signaling, beta‐adrenergic signaling and insulin signaling. Specifically we were able to identify Insulin signaling pathway as a novel pathway being regulated by CaMKIId inhibition.ConclusionCaMKIId is a key mediator of contractility, electrophysiology, calcium handling and insulin signaling within cardiomyocytes.Support or Funding InformationNIH grant 1R01HL105242
Failing Hearts are More Sensitive to Sympathetic, But Less Sensitive to Vagal Induced Atrial Fibrillation in Rats
Authors: Delfiner Matthew S. , Li Ying , Gerdes A. Martin , Zhang Youhua 
Published: November 2023

IntroductionBoth vagal (VS) and sympathetic (SS) stimulation have been shown to increase atrial fibrillation (AF) inducibility, with VS being more arrhythmogenic in normal hearts. Heart failure (HF) results in autonomic dysfunction, characterized by sympathetic activation and vagal withdrawal, and is associated with an increased incidence of AF. However, it is unknown whether failing hearts respond differently to autonomic stimulation in AF inducibility.MethodsMyocardial infarction was produced by left anterior coronary artery ligation in 9 rats, with 10 sham‐operated animals serving as controls. Infarcted rats developed HF 2 months after surgery as determined by echocardiography and hemodynamic measurements. AF inducibility was tested under anesthesia at terminal experiments by burst pacing (200 impulses at 50 Hz) in 5 consecutive episodes. The occurrence and duration of spontaneous AF after burst pacing was determined in each episode. AF inducibility was evaluated at baseline, during right cervical vagus nerve stimulation (30 Hz, 0.1 ms duration and 1 mA), and during SS with isoproterenol infusion (0.1ug/kg/min).ResultsSee figure. Compared to controls, HF increased AF inducibility. Both the incidence and duration (not shown) were increased at baseline. AF inducibility was augmented in both groups by VS. However, the magnitude of increase was less in the HF group (increased 49% in HF vs 80% in controls). AF inducibility was significantly increased in HF hearts under SS, compared with sham‐controls.ConclusionsAutonomic stimulation can increase AF inducibility in both HF and control animals. Compared to controls, failing hearts are less sensitive to VS, but more sensitive to SS. The increased sensitivity of failing hearts to SS may explain why “sympathetic AF” is typically seen in patients with structural heart disease and “vagal AF” is usually seen in normal hearts.
Myocardial Electrotonic Coupling Modulates Repolarization Heterogeneities in vivo: Implications for the Assessment of Pro‐Arrhythmic Liabilities in vitro and in silico
Authors: del Rio Carlos L , Hamlin Robert L , Billman George E 
Published: November 2023

Passive electrical properties determining electrotonic cell‐to‐cell coupling in the myocardium can modulate repolarization disturbances/heterogeneities; in short, poorly‐coupled cells exert limited electrotonic influence(s) over their neighbors (i.e., lower space constant) facilitating induced/acquired heterogeneities, and therefore, pro‐arrhythmic potential/behaviors. This study investigated, both in vivo and in silico, the effects of changes in myocardial electrotonic coupling on clinically‐relevant indices of arrhythmic liabilities.Electrotonic coupling in vivo, both at rest and/or during acute ischemia, was modulated by interventions affecting autonomic balance/β‐adrenoceptor (β‐AR) signaling. At rest, acute ischemia induced marked electrotonic uncoupling but β‐AR activation enhanced it; ischemic passive electrical derangements were blunted by vagal‐nerve stimulation and complete/partial β‐AR blockade but were enhanced by exercise. Overall, electrotonic derangements were well correlated with changes in the rate‐corrected QT‐interval (QTc, R2 =0.89, P<0.05) and/or the with duration (terminal‐portion) of the T‐wave (TPEc, R2 = 0.81, P < 0.05); these responses were well‐modeled in silico by introducing (only) aspatially heterogeneous coupling resistance in a one dimensional structure of propagating cardiac action potentials following the Luo‐Rudy formulation. Electrotonic uncoupling also predicted ischemic T‐wave alternans (TWA, R2 = 0.82, P<0.05), a known risk‐marker for malignant arrhythmias in the clinic.Taken together, these data demonstrate that the degree of ventricular electrotonic uncoupling can explain, at least partially, pro‐arrhythmic electrocardiographic changes reflective of myocardial repolarization abnormalities in vivo, and therefore, it must be considered when examining pro‐arrhythmic liabilities in vitro and/or in silico.
Osteopontin Attenuates Changes in Cerebrovascular Structure‐Function Relations Induced by Subarachnoid Hemorrhage in Rat Brain
Authors: Kim Dahlim , Doan Coleen , Carreon Desirelys , Budbazar Enkhjargal , Zhang John H , Pearce William J 
Published: November 2023

Subarachnoid hemorrhage (SAH) is a common injury involving a complex and incompletely understood etiology. The present study explores the hypothesis that brain injury caused by SAH involves major changes in the structure and function of small cerebral arteries, in addition to its well‐known effects on neurons, glia and capillary endothelium. To evaluate this hypothesis, we studied the effects of SAH via endovascular perforation of the bifurcation of the anterior and middle cerebral arteries (MCA) in the adult rat brain. Artery samples were harvested 24 hours post‐injury for assessment of vascular structure and function. To test if the 44 kDa extracellular matrix protein Osteopontin (OPN) could serve as a vasoprotectant, some animals were treated with OPN via intranasal administration (5 μg in 50 μl PBS) at 1 hour post‐injury. As indicated by MLCK‐MLC20 colocalization quantified via confocal microscopy, SAH caused a significant 32% increase in contractile differentiation. This effect of SAH was attenuated by 66% (11% increase) following treatment with OPN. Simultaneously, SAH decreased the magnitude of the cytosolic calcium response to potassium depolarization by 28 nM (19%), and this effect was reversed to an increase of 41nM (49%) after OPN treatment. Additionally, SAH caused a passive dilation of 13 μM compared to untreated Sham control arteries, and after OPN treatment, this dilation was reduced to only 4 μM (69% reduction). Together, these results illustrate that SAH induces vascular injury that is largely prevented by intranasal treatment with OPN. Specifically, SAH promotes passive dilation and increased contractile differentiation, but compromises regulation of cytosolic calcium; these effects are consistent with the development of cerebral vasospasm and/or loss of cerebral autoregulation, both of which are well‐known consequences of SAH. Interestingly, OPN can bind and activate multiple integrin receptors, can promote inflammation via neutrophil recruitment, and can interact with other vasotrophic growth factors such as VEGF. It is not clear which, if any or all of these factors contribute to its neuroprotective profile. The present study strongly suggests that OPN is also vasoprotective within the context of SAH, which may contribute significantly to its neuroprotective efficacy.Support or Funding InformationThese studies were supported by an NIH Program Project grant from NINDS (NS082184), and an NIH R01 grant also from NINDS (NS076945).