bluuebunny/crossref_metadata_2025 huggingface dataset:
IGF‐1 induces proliferation and T3 causes maturation of cultured embryonic chicken cardiomyocytes
Authors: Svensson‐Holm Ann‐Charlotte B , Lindgren Isa , Österman Hanna , Altimiras Jordi
Published: June 2021

Fetal cardiac growth in mammalian models occurs primarily by cell proliferation (hyperplasia). However, close to term most cardiomyocytes lose the ability to proliferate and heart growth continues by increase in cell size (hypertrophy). The thyroid hormone T3 is an important driver of this process. In contrast, chicken cardiomyocytes keep their proliferating ability long after hatching but little information is available on the mechanisms controlling cell growth and myocyte maturation in the chicken heart. Our aim was to study the effect of T3, IGF‐1 and Ang‐II on the proliferation and growth of embryonic chicken cardiomyocytes (ECCM), enzymatically isolated from E19 chicken embryos. Hyperplasia was measured using a proliferation assay (MTS) and hypertrophy/maturation was analysed morphologically by phalloidin staining of F‐actin and nuclear staining with DAPI. We show that IGF‐1 induces a significant increase in ECCM proliferation (30%) which is absent with T3 or Ang‐II. The thyroid hormone T3 caused multinucleation while none of the treatments had any hypertrophic effect. In conclusion, our results are similar to those obtained in sheep cardiomyocytes and show that ECCM proliferation is mediated through mechanisms involving IGF‐1 while T3 causes maturation. Supported by FORMAS Centre of Excellence in Animal Welfare Science and career grant from Linköpings universitet to JA.
Lithium promotion of connexin43 protein in infarcted rats by Wnt‐ and PI3K/Akt‐dependent GSK‐3β phosphorylation signaling
Authors: Lee Tsung‐Ming , Hsu Yu‐Jung
Published: June 2021

The purpose of this study was to determine whether lithium can attenuate arrhythmias through increasing GSK‐3β/β‐catenin‐induced connexin43 by activating Wnt and phosphoinositide‐3 kinase (PI3K)/Akt after myocardial infarction. Male Wistar rats were subjected to coronary artery ligation and then randomized to either saline or lithium treatment for 4 weeks. Myocardial connexin43 levels were significantly decreased in the saline‐treated infarcted rats compared with sham. These attenuated connexin43 levels were blunted after lithium. Arrhythmic scores during programmed stimulation in the lithium‐treated infarcted rats were significantly lower than those treated with the saline‐treated infarcted rats. Lithium increased Akt phosphorylation 4.5‐fold in the border zone compared to saline after infarction. The two downstream targets of Akt, phosphorylated GSK‐3β and nuclear translocated β‐catenin were significantly increased by 11.2‐fold and 3.6‐fold, respectively. Inhibition of Wnt and PI3K/Akt signaling prevented GSK‐3β phosphorylation as well as β‐catenin nuclear translocation, and blocked the beneficial effects of lithium on connexin43 phosphorylation. Chronic use of lithium after infarction, resulting in enhanced connexin43 levels through both Wnt‐ and PI3K/Akt‐dependent GSK‐3β pathways may attenuate the arrhythmogenic response to programmed electrical stimulation.
The effects of sex and hypertension subtype on left ventricular size and function in seniors
Authors: Best Stuart , Okada Yoshiyuki , Fujimoto Naoki , Hamati Joseph , Matulevicius Susan A , Abdullah Shuaib , Levine Benjamin D , Fu Qi
Published: June 2021

We compared sex and hypertension (HTN) subtype associated differences in cardiac size and function in seniors. Fourteen normotensive (NT) men (67 ±6 [SD] yrs) and 15 women (69 ±8 yrs), 10 men (67 ±2 yrs) and 10 women (71 ±6 yrs) with stage 1 isolated systolic HTN (ISH) and 10 men (69 ±5 yrs) and 10 women (66 ±8 yrs) with systolic‐diastolic HTN (SDH) were studied. Patients were weaned from their antihypertensive drugs. All participants underwent a 3‐wk run‐in period before testing and 24‐h ambulatory blood pressure was measured. Cardiac size and function was assessed by MRI and analyzed for left ventricular mass (LVM), end diastolic volume (LVEDV) and end systolic volume (LVESV). Mass to volume ratio (MVR), ejection fraction (EF), stroke volume (SV) and cardiac output (Qc) were calculated. LVM and MVR were higher in SDH (LVM, 122.2 ±31.4g) and ISH (108.6 ±26.8g) compared to NT (92.3 ±22.5g) while EF was higher in ISH only (all P<0.05). MVR and LVM were significantly higher in the SDH compared to ISH (both P<0.05). LVEDV, LVESV, SV and Qc were not significantly different between the groups. Women had a lower normalized LVM, LVEDV and LVESV, lower MVR and higher EF than their respective male counterparts (all P<0.05). Thus HTN subtype affects cardiac size and function in seniors and may be due to greater central arterial stiffness in ISH and greater LV afterload in SDH, but the effect of sex is consistent despite the presence of hypertension.
Vascular function in cavin‐1‐deficient mice: role of arginase 1 and dimethylarginine dimethylaminohydrolase 1
Authors: Rippe Catarina , Sadegh Mardjaneh Karbalaei , Mori Michiko , Erjefält Jonas E , Albinsson Sebastian , Persson Lo , Swärd Karl
Published: June 2021

Caveolae are invaginations in the plasma membrane important for normal cardiovascular function. Mice lacking caveolin‐1, a protein involved in caveolae biogenesis, show altered vascular function. Cavin‐1/PTRF is a recently identified protein critical for caveolae formation. Our aim was to investigate vascular function in mice deficient in cavin‐1. We found that cavin‐1 knock‐out (KO) mice have increased perinatal lethality. In mice that survived to adulthood we found remodeled blood vessels both in the periphery and in the lung. A microarray performed on lungs from newborn cavin‐1 KO mice showed altered expression enzymes involved in nitric oxide (NO) production, elevated Arginase1 (Arg1) and reduced dimethylarginine dimethylaminohydrolase 1 (DDAH1). In vitro studies in small arteries using myography show an enhanced relaxation to an Arg1 inhibitor (NOHA), confirming an increased enzyme activity in cavin‐1 KO mice. Decreases in DDAH1 have been shown to lead to pulmonary hypertension. We found that the decrease in DDAH1 expression was associated with an increased pressure in the right ventricle of the heart, suggesting a mild pulmonary hypertension in cavin‐1 KO mice. In spite of this, systemic blood pressure was normal. In conclusion, we find alterations in NO regulating enzymes that may be involved in limiting NO production in cavin‐1 deficient mice and resulting in mild pulmonary hypertension.
Effect of dietary calcium supplementation on store‐operated calcium entry in coronary smooth muscle cells from Ossabaw miniature swine with coronary artery disease
Authors: Martin John Robert , Lee McKenney Mikaela , Weaver Connie M. , Sturek Michael
Published: June 2021

Coronary smooth muscle (CSM) cells of Ossabaw swine in the early stages of coronary artery disease have increased storeoperated calcium/cation entry (SOCE). Pigs (N=24) were fed for 6 months an atherogenic diet containing 0.5% Ca (control, C), or 2% Ca by supplementation with either calcium carbonate (high supplement, HS) or non‐fat milk (high dairy, HD) to determine effects on CSM SOCE. At euthanasia atherosclerosis was quantified with intravascular ultrasound and CSM cells were enzymatically isolated and loaded with fura‐2 to measure cytosolic Ca. The manganese (Mn) quench technique was used to assess SOCE after depletion of the sarcoplasmic reticulum (SR) with 5 mM caffeine. While maintaining SR depletion with 10 μM cyclopiazonic acid, the rate of quenching of fura‐2 fluorescence was measured as the percent change in pixel intensity/time (%Δ/min) to estimate SOCE. Mn quench from 64, 59, and 46 CSM (from 2 pigs/group) was in %Δ/min: C=−0.37±0.24, HD=0.04±0.01, HS=−0.42±0.51. These initial data suggest that Ca supplementation by skim milk prevented the increase in SOCE in CSM in atherosclerosis.

(Support: NIH HL062552)
A new NO donor [Ru(bpy) 2 (pyNO2](PF6) (RuBPY) free and loaded in polymeric nanoparticles (PNP) induce similar vasodilatation in normotensive (2K) and renal hypertensive rat aorta (2K‐1C).
Authors: de Campos Araujo Luciana Mattoso Pires , Silva Roberto Santana , Lopez Renata Fonseca Vianna , Bendhack Lusiane Maria
Published: June 2021

This work aimed to prepare and characterize formulations containing the RuBPY free and loaded in PNP prepared by nanoprecipitation and to verify if its formulation induces relaxation in isolated aorta from 2K‐1C and 2K rats. We have analyzed the maximum effect (ME) and potency (pD2). P values ¡Ü0.05 were significant. The average diameter, polydispersity index (pdI) and encapsulation efficiency of RuBPY were determined. Vascular reactivity experiments were performed on denuded aorta contracted with phenylephrine. The better PNP obtained presented 84.12nm average diameter and pdI 0.113. After RuBPY loaded PNP presented 104.9±1.86 nm and pdI 0.123±0.03. The developed PNP were able to encapsulate around 44.8% of RuBPY. Formulation containing RuBPY induced relaxation with similar ME and pD2 in 2K (ME:98.7±2.6%, pD2:6.32±0.098, n=3) and 2K‐1C rats (ME:101.1±0.4%, pD2:6.14 ±0.064, n=4). The pD2 was lower in RuBPY formulation than in RuBPY free, 2K (ME:112.7±34.6%, pD2:7.37±0.11, n=8) and 2K‐1C rats (ME:114.6±6.3%, pD2:7.19±0.12, n=5). RuBPY formulation is a potential vasodilator and this effect is similar in 2K and 2K‐1C rat aorta but it was less potent than RuBPY free. Supported by FAPESP and CNPq.
Decreased activation of Placental mTOR is Associated with Increase Invasive trophoblast 4EBP1 activation during Intrauterine Growth Restriction (IUGR) development in the Rat
Authors: Arroyo Juan Alberto
Published: June 2021

Intrauterine growth restriction (IUGR) is a significant obstetric complication that affects up to 8% of all pregnancies. It is known that the IUGR fetus and newborn are at significant risk for morbidity and mortality and the adult offset of hypertension and coronary heart disease. A number of placental abnormalities have been described in IUGR including decreased trophoblast invasion. mTOR is a protein that regulates cell growth in response to nutrients and growth factors. Members of the mTOR pathway also include the p70 and the 4EBP1proteins. Activation of these proteins increases protein synthesis by different pathways. Our objective was to determine the role of the mTOR pathway proteins in the placenta and invasive trophoblast cells in the in a new model of hypoxia induced IUGR in the rat. Rats were treated with hypoxia (9%) for 4 days to develop IUGR. At the time of necropsy placental and fetal weight were recorded. We observed: 1) decreased placental (21%) and fetal (24%) weights (p<0.05) 2) decreased trophoblast invasion 3) no changes in activation of mTOR and p70 proteins with a significant activation for 4EBP1 (28%; p<0.05) in the invasive trophoblast, and 4) a significant decrease in mTOR activation (48%; p<0.05) with no differences in the for p70 or 4EBP1. We conclude that the development of IUGR is correlated with a decreased in activation of the mTOR protein in the placenta and increase in 4EBP1 activity in the invading trophoblast. These results could give some insights into the physiological relevance of these pathways, if so their modification during gestation could help alleviate this disease.
Alterations in the AKT/mTOR pathway in dystroglycanopathy muscle
Authors: Foltz Steven J , Beedle Aaron M
Published: June 2021

Secondary dystroglycanopathies are a subset of muscular dystrophies caused by aberrant glycosylation of α‐Dystroglycan (DG). Hypoglycosylated αDG is unable to bind to its extracellular targets, disrupting a crucial link between the extracellular basement membrane and the intracellular cytoskeleton. FKTN, encoding fukutin, is one of several genes identified as causative for dystroglycanopathy. Similar to human patients, skeletal muscle from conditional fukutin KO mice shows a progressive dystrophic phenotype. The objective of our study is to characterize alterations in cellular signaling pathways in dystroglycanopathy disease using a conditional Fktn knockout mouse model. Using techniques to monitor gene expression, protein expression and protein phosphorylation, we find that there are alterations in multiple factors in the PI3K/AKT/mTOR signaling cascade in young Fktn KO mice. Furthermore, preliminary data suggest a differential response to pharmacological inhibition of this pathway between KO mice and age‐matched littermate controls. Our findings indicate that changes in the AKT/mTOR signaling pathway are present in young Fktn KO mice, but the precise role of AKT/mTOR signaling in dystroglycanopathy muscle requires further clarification.

Research supported by the University of Georgia College of Pharmacy.
Effect of meal size on total daily energy intake among people with type 2 diabetes
Authors: Jarvandi Soghra , Schootman Mario
Published: June 2021

We assessed the association between distribution of energy intake and total daily energy intake among individuals with type 2 diabetes, using data from 1219 men and women who completed the 1999–2004 National Health and Nutrition Examination Survey (NHANES). History of diabetes was self‐reported. Daily energy intake, overall and by meal (breakfast, lunch, dinner) and snack, was estimated from a 24‐h food frequency questionnaire. Multiple regression models were used to estimate the association between percent of daily energy intake at each meal and snack with daily energy intake. Models were controlled for sex, age, race/ethnicity, body mass index and physical activity. Intake of energy (mean ± standard deviation), as percent of total daily intake, at breakfast, lunch, dinner and snack was 22.9% ± 15.7%, 23.2% ± 20.0%, 35.2% ± 21.3%, and 12.4% ± 16.3%, respectively. A larger breakfast (≥ 20% vs. <10% of total daily calories) was associated with 293 ± 104 (mean ± standard error) kilocalories lower total daily energy intake. No association was found between meal size at lunch, dinner or snack and total energy intake. The results suggest a possible role of food pattern in daily intake of energy. Consuming a higher energy breakfast may help decrease the overall daily intake of energy, which is critical for management of type 2 diabetes.
Life's simple 7 (LSS) and its associations with coronary artery calcium (CAC): the Jackson Heart Study (JHS)
Authors: Talegawkar Sameera A , Chen Ping , Liu Jiankang , Hickson DeMarc A , Maras Janice , Manjourides Justin , Correa Adolfo , Griswold Michael , Taylor Herman A , Tucker Katherine L
Published: June 2021

The American Heart Association (AHA) defined a LSS metric, of ideal cardiovascular (CV) health factors and health behaviors as a measure consistent with healthy longevity. Associations of this metric with CAC are not well described in African Americans (AA). An ideal CV health score was created with baseline cohort data from the JHS, a population‐based cohort of AA adults, as the sum of the 7 metrics, each coded as dichotomous variables (1 point AHA ideal, 0 for other). The total score range is 0–7, categorized as 0–1, 2–4, and 5–7. CAC was assessed at approx. 4 y after baseline with CT scans; CAC was defined as Agatston score >;0. Included in these analyses were 2,148 participants (66.5% women, mean age 54.7 y) with complete data on the CV health score, CAC, and without a history of coronary heart disease or stroke at baseline. The percentage of participants with 0, 1, 2, 3, 4, 5, 6, and 7 ideal CV health scores were 3.4, 15.3, 32.1, 29.1, 14.5, 5.2, 0.5 and 0 respectively. At 4 y follow‐up, 44% of the cohort had an Agatston score >;0. After adjustment for age, sex, and education, higher scores were associated with decreased odds of CAC. Corresponding Odds Ratios were 1.0 (score 0–1, reference), 0.41 (score 2–4, 95% CI 0.31, 0.52) and 0.30 (score 5–7, 95% CI 0.18, 0.51). In this cohort of AA adults, CV health assessed using the LSS metric was independently associated with CAC, suggesting that this is a valid measure of risk in this population.
Nut intake and risk of metabolic syndrome
Authors: Jaceldo‐Siegl Karen , Oda Keiji , St John Claire , Sabaté Joan
Published: June 2021

Studies of nut intake and metabolic syndrome (MetS) risk are sparse. We examined the relationship between nut consumption and MetS in the Adventist Health Study, a population with a wide range of nut intake ranging from never to daily. The analytic sample included 747 adults with complete demographic, diet, anthropometric, and clinical data. MetS was defined according to the AHA/NHLBI diagnostic criteria. Diet was assessed by a 204‐item FFQ (validated against 24‐hr diet recalls) including 8 items on nuts. Validity correlations were moderate for tree nuts and low to moderate for peanuts and peanut butter. Intake of tree nuts (T), peanuts + peanut butter (P), and total nuts (T+P) was quantified and categorized. Odds ratios with 95% CI were estimated using multivariable logistic regression. 35% of subjects had MetS. Total and tree nuts had an inverse association with MetS. Individuals with high total nuts intake (>;3 servings/week) had 34% less MetS than individuals with low intake (<1 serving/week) (OR=0.66, 95% CI: 0.43–0.99). Consumption of 1/day of tree nuts was associated with 20% lower odds of MetS (OR=0.80, 95% CI: 0.65–0.99). Consumption of peanuts was not related to MetS. In a population with high range of nut intake, consumption of total and tree nuts but not peanuts is associated with lower MetS. This association is independent of demographic, lifestyle and other dietary factors.

Funding: NIH 1RO1 CA 94594 (data collection) and International Nut Council
Effect of heat stress on body temperature, respiratory frequency and performance of pigs
Authors: Morales Adriana , Cota Margarita , Arce Nestor , Castillo Gilberto , Cervantes Miguel , Araiza Alfonso
Published: June 2021

The effect of ambient temperature (AT) on body temperature (BT), respiratory frequency (RF), and performance of pigs was evaluated. Eighteen pigs (32.6 kg body weight) were distributed in three treatments: 1) housed at 25 °C (Comfort) and fed ad libitum (AL); 2) as in 1, but feed restricted (REST); 3) housed under heat stress (34.3 °C, HS). The AT, heat index (HI), BT, RF and pig performance were measured. The amount of feed consumed (FI) by HS pigs fed ad lib was the same offered to the REST pigs. Average HI in the Comfort and HS rooms was 81 and 102. Treatment results for AL, REST, and HS were: BT, 38.3, 37.9, 39.2 °C; RF, 60, 49, 103; weight gain (ADG), 688, 525, 501 g/d; feed intake (FI), 1.47, 1.20, 1.17, respectively. HS pigs had higher BT, RF but lower ADG and FI (P<0.01) than those in comfort. AL pigs had higher BT, RF, ADG and FI than REST pigs (P<0.01). BT and RF of HS pigs, measured from 0800 to 2000 h, increased from 38.4 to 39.6 °C and from 62 to 113, as AT increased from 26 to 42 °C. These results show a marked effect of AT on BT, RF, ADG and FI of pigs, and suggest that pigs are capable of overcoming rapid and huge AT changes when they are exposed to HS. Financial support by UABC.
Role of nitric oxide synthase on local sweat rate in older adults during intermittent exercise in the heat
Authors: Stapleton Jill , Carter Michael , Kenny Glen P.
Published: June 2021

Studies suggest that nitric oxide (NO) has a role in sweating. Older adults have a lower production of and sensitivity to NO which may explain why older adults have lower local sweat rates (LSR) compared with their younger counterparts during exercise. We examined the role of NO synthase (NOS) on LSR during intermittent exercise in the heat. Ten young (Y) and ten older (O) participants completed 3 × 15 min of cycling (rate of metabolic heat production of 600 W) separated by 15 min recovery in the heat (35ºC, 30% RH). Intradermal microdialysis probes were inserted in the forearm and perfused with either 0.9% saline (CON) or 10 mM L‐NAME (a NOS inhibitor). LSR was measured directly over each membrane. LSR was similar between Y and O during the exercise bouts at the CON (average of the 3 exercise bouts: Y; 0.96 ± 0.20 vs. O; 0.87 ± 0.25 mg·min−1·cm−2 p=0.327) and the LNAME (Y: 0.74 ± 0.18 vs. O: 0.83 ± 0.27 mg·min−1·cm−2 p=0.327) sites. However, the relative contribution of NO to the sweating response was reduced in Y (CON: 0.96 ± 0.20 vs. L‐NAME: 0.74 ± 0.18 mg·min−1·cm−2, p=0.017), but not O (CON: 0.87 ± 0.25 vs. L‐NAME: 0.83 ± 0.27 mg·min−1·cm−2, p=0.965). We conclude that the exercise‐induced increase in sweating is influenced by NO in younger adults. However, it appears that the level of influence is blunted in older individuals during high intensity exercise in the heat.

This research was funded by Natural Sciences and Engineering Research Council (RGPIN‐298159–2009, held by Dr. Kenny).
Countermeasures against post‐exercise syncope
Authors: Buck Tahisha M , Lacewell Alisha N , Halliwill John R
Published: June 2021

Following exercise, a decrease in central blood volume can compromise cerebral perfusion and result in syncope. Breathing through an impedance threshold device (ITD) has been shown to restore central blood volume under several hypovolemic conditions. Therefore, we hypothesized that ITD breathing would prevent post‐exercise syncope following a 1‐min Wingate test. We studied 19 recreationally active men and women, subjecting them to a 60° head‐up tilt during recovery from the Wingate test. Measurements included arterial pressure, heart rate, end‐tidal PCO2, and cerebral tissue oxygenation index on a control and breathing intervention (ITD) day. Mean arterial pressure was greater during the last 30 sec of head‐up tilt on the ITD day compared to the control day (97.1 ± 2.1 vs 91.9 ± 1.8 mm Hg; P < 0.05). Cerebral tissue oxygenation tended to be greater during the last 30 sec of head‐up tilt on the ITD day compared to the control day (71.8 ± 0.6 vs 70.7 ± 0.8 mm Hg; P = 0.07). The length of head‐up tilt was compared between study days for each subject. When contrasting this difference, the ITD lengthened the median tilt time by 7 min 20 sec (P = 0.20). These data suggest that the ITD may be beneficial in preventing post‐exercise syncope induced by a Wingate exercise model.
Effects of Arterial Territory on Dynamic Cerebral Autoregulation
Authors: Falvo Michael J , Blatt Melissa M , Acosta Amanda , Ghobreal Bemin , Serrador Jorge M
Published: June 2021

Studies of cerebral autoregulation are often limited to the middle and anterior cerebral arteries (MCA, ACA) and do not include the vertebral artery (VA). Therefore, it is not well known whether major cerebral arteries differ in their response to sudden changes in arterial blood pressure (ABP) as seen with a postural maneuver. 22 subjects (11 women) performed 3 sit‐to‐stand maneuvers (Age 29.6±11.5 yrs, Height 172.7±7.5 cm, 75.6±14.9 cm, BMI 25.3±4.2). Cerebral blood flow was recorded continuously (MCA, ACA, VA) along with ABP, end‐tidal CO2 and heart rate. We computed an autoregulatory index (ARI) for each artery based on Tiecks et al. (1995) model. We observed a significant main effect for arterial territory (p = 0.003; MCA: 2.6±1.7, ACA: 2.4±1.7; VA: 3.8±2.0). Pairwise comparisons (Bonferonni corrected) indicated that ARI values for the VA were significantly higher than both the MCA (p = 0.002) and ACA (p = 0.002). Our data suggest that based on ARI, the VA exhibits better autoregulation than the MCA or ACA – perhaps reflective of a protective mechanism to ensure adequate blood flow to the brainstem. Future studies should consider the inclusion of the VA into their assessment which may have particular relevance in the evaluation of several clinical disorders including orthostatic intolerance. Work supported by NJ WRIISC.
Distribution of internal and external cranial blood flows during whole body heating
Authors: Shibasaki Manabu , Sato Kohei , Okazaki Kazunobu , Miyamoto Tadayoshi , Hirasawa Ai , Ogoh Shigehiko
Published: June 2021

In hyperthermic condition, cerebral blood flow decreases while cardiac output is increased. Recently we observed the altered distribution of internal and external cranial blood flows during dynamic exercise; external carotid artery (ECA) and vertebral artery (VA) blood flows increased proportionally with workload although internal carotid artery (ICA) blood flow increased during light and mild exercises but decreased during intense exercise. The increased body temperature might modulate distribution of these blood flows. To test this hypothesis, we assessed the distribution of these blood flows during a passive heat stress. Twelve young healthy subjects dressed tube‐lined suit and rested in a supine position. ICA, ECA and VA blood flows were measured by ultrasonography. Esophageal temperature (Tes) was increased by circulating hot water through the suit. Tes was increased from 37.0±0.3 °C to 38.5±0.3 °C during whole body heating. The heat stress increased ECA blood flow from 179±76 to 409±193 ml/min, while ICA and VA blood flows decresaed from 293±63 to 235±59 ml/min and from 91±37 to 82±35 ml/min, respectively. During heat stress, ECA and VA blood flows gradually increased and decreased, respectively. Interestingly, ICA blood flow did not change until Tes was elevated by ~1 °C, then significantly decreased at the end of heat stress.
Dynamic cerebral autoregulation after acute cigarette smoking in non‐smokers and habitual smokers
Authors: Peebles Karen C , Horsman Helen M , Tzeng Yu‐Chieh
Published: June 2021

Introduction

Cigarette smoking is associated with an increased risk of stroke in a dose dependent manner. Impaired baroreceptor function, associated with hypertension and increased blood pressure (BP) variability, offers one potential mechanism for smoking‐induced stroke risk. However, studies to date have not assessed whether smoking impairs dynamic cerebral autoregulation (dCA) or the interplay between dCA and baroreflex function in smokers. Thus, this study examined the impact of acute and chronic cigarette smoking on dCA and baroreflex function.

Methods

We recruited 17 non‐smokers and 15 habitual smokers. Transfer function analysis was used to examine dCA and baroreflex sensitivity before and immediately after acute smoking (a single cigarette) during spontaneous breathing.

Results

There were no between‐group differences in dCA metrics (gain, phase and coherence) or low frequency baroreflex gain at baseline. However, both groups, showed a decrease in transfer function gain and coherence and increase in phase, after acute smoking, suggesting improved dCA. This increase in dCA was accompanied by a reduction in baroreflex gain, and increase in BP variability.

Conclusion

These novel findings suggest that an increase in dCA counteracts the impact of impaired baroreflex function, potentially buffering the delicate cerebral vessels from the increase in BP variability after acute smoking.
Consequences of neonatal sustained and intermittent hypoxia on spontaneous and evoked activities of nucleus tractus solitarius (nTS) neurons
Authors: Mayer Catherine Ann , Wilson Christopher , MacFarlane Peter
Published: June 2021

We showed previously that neonatal sustained hypoxia (SH=11% O2, postnatal (P) day 1–5) followed by chronic intermittent hypoxia (CIH=5%O2 45s/5min 8 hrs/day, P5‐P15) attenuated the ventilatory response to acute hypoxia. We hypothesized that this attenuated response was associated with impaired activity of neurons in an area of chemoafferent integration, the nucleus tractus solitarius (nTS). We used whole‐cell patch clamp recordings to examine the excitatory properties of nTS neurons monosynaptically connected to the solitary tract in neonatal (P16) rats treated with SH prior to CIH (SH+CIH). SH+CIH exposure decreased the frequency of spontaneous EPSCs in nTS neurons compared to normoxic rats. Amplitude, rise time, decay time, and area did not differ. The amplitude of evoked EPSCs in monosynaptically connected nTS neurons was increased in the SH+CIH group compared to normoxic rats. Contrary to our hypothesis, neurons from the nTS of SH+CIH exposed animals exhibit increased excitability (evoked responses), which may be a compensatory mechanism resulting from neonatal hypoxia. These data may be important to understanding the potential effects of inadequate oxygenation in the neonatal period on nTS neurons.
Structure‐based mechanism for the adaptation of apolipoprotein A‐I to the changing lipid load in Good Cholesterol
Authors: Gursky Olga
Published: June 2021

High‐density lipoproteins (HDL) and their main protein, apoA‐I, remove excess cell cholesterol and protect against atherosclerosis. Heterogeneity and large size of HDL (8–12 nm) hamper their high‐resolution structural studies. Low‐resolution studies showed that two apoA‐I molecules form an antiparallel α‐helical double belt around an HDL particle. High‐resolution structure of the C‐terminally truncated apoA‐I solved by Mei and Atkinson provides tremendous new insights into HDL structure‐function. It enables us to propose apoA‐I conformations on the small, midsize and large HDL and validate them by comparison with extensive biophysical data. We postulate that the central “constant” half of the double belt is structurally conserved while the N‐and C‐terminal “variable” half re‐arranges upon HDL growth. This includes sequential unhinging of the N‐terminal bundle around two flexible Gly‐containing regions to elongate the belt, along with concerted swing motion of the double belt around G65‐P66 and G185‐G186 hinges that are aligned on various‐size particles, to confer 2D surface curvature to spherical HDL. Our ensemble reconciles several existing HDL models and helps provide a structural framework for understanding functional interactions with ~60 other HDL‐associated proteins and, ultimately, to improve cardioprotective function of HDL. This work was supported by NIH grants HL026355 and GM067260.
Aurora Kinase A (AURKA) Regulates the Vacuolar H+‐ATPase (V‐ATPase) in Kidney Carcinoma Cells
Authors: Al‐bataineh Mohammad M. , Alzamora Rodrigo , Gong Fan , Marciszyn Allison L. , Hallows Kenneth R. , Pastor‐Soler Nuria M.
Published: June 2021

The V‐ATPase mediates kidney H+ secretion and is involved in metastasis. V‐ATPase A subunit phosphorylation at Ser175 is important for PKA‐mediated V‐ATPase activity in intercalated cells (ICs). The metabolic sensor AMP‐activated kinase (AMPK) prevents V‐ATPase apical accumulation by PKA in ICs. We hypothesized that AURKA overexpressed by aggressive carcinomas regulates the V‐ATPase in human kidney carcinoma cells (Caki‐2) via Ser‐175. AURKA is abnormally expressed in Caki‐2 cell cytoplasm and phosphorylates the V‐ATPase A subunit at Ser175 in vitro and in Caki‐2 cells. Higher pSer175 was detected from cells transfected with WT A subunit and treated with an AURKA activator, compared to untreated cells, and compared to cells expressing an S175A A‐subunit mutant. Caki‐2 cell immunolabeling revealed that an AURKA activator induced marked V‐ATPase membrane accumulation in cell projections compared to untreated cells. AURKA activation enhanced the rate of wound healing in Caki‐2 cells compared to untreated cells. AMPK activation blocked the AURKA‐induced effects on V‐ATPase membrane accumulation and wound healing. AURKA‐mediated V‐ATPase regulation may have a role in the metastatic potential of kidney carcinomas and may represent a potential therapeutic target. Supported by NIDDK.
Comparative Genomics Identifies The Mouse Bmp3 Promoter and an Upstream Evolutionary Conserved Region (ECR) in Mammals
Authors: Lowery Jonathan Wayne , LaVigne Anna W , Kokabu Shoichiro , Rosen Vicki
Published: June 2021

The Bone Morphogenetic Protein (BMP) pathway is an ancient, multi‐member signaling cascade whose basic components are found in all animals. One member, BMP3, which is found only in deuterostomes, serves a unique role as an antagonist to both the canonical BMP and Activin pathways. However, the mechanisms and cis‐regulatory regions controlling BMP3 expression remain poorly defined. With this in mind, we sought to identify the Bmp3 promoter in mouse through functional and comparative genomic analyses. We found that the minimal promoter required for expression resides within 0.8 kb upstream of Bmp3 in a region that is highly conserved with rat. We also found that an upstream region abutting the minimal promoter acts as a repressor of the minimal promoter. Strikingly, a portion of this region is conserved among all available eutherian mammal genomes (47/47), but not in any non‐eutherian animal (0/136). We also identified multiple conserved transcription factor binding sites in the Bmp3 upstream ECR, suggesting that this region may preserve common cis‐regulatory elements that govern Bmp3 expression across eutherian mammals. Since dysregulation of BMP signaling appears to play a role in human health and disease, our findings may have application in the development of novel therapeutics aimed at modulating BMP signaling in humans. This work was supported by an American Recovery & Reinvestment Act Award.
Monolayer Stress Microscopy: limitations, artifacts, and accuracy of recovered intercellular stresses
Authors: Tambe Dhananjay T. , Croutelle Ugo , Trepat Xavier , Kim Jae Hun , Millet Emil , Butler James P , Fredberg Jeffrey J
Published: June 2021

In wound healing, tissue growth, and certain cancers, the epithelial or the endothelial monolayer sheet expands. Within the expanding monolayer sheet, migration of the individual cell is strongly guided by physical forces imposed by adjacent cells. This process is called plithotaxis and was discovered using Monolayer Stress Microscopy (MSM). MSM rests upon certain simplifying assumptions, however, concerning boundary conditions, cell material properties and system dimensionality. To assess the validity of these assumptions and to quantify associated errors, here we report new analytical, numerical, and experimental investigations. For several commonly used experimental monolayer systems, the simplifying assumptions used previously lead to errors that are shown to be quite small. Out‐of‐plane components of displacement and traction fields can be safely neglected, and characteristic features of intercellular stresses that underlie plithotaxis remain largely unaffected. Taken together, these findings validate Monolayer Stress Microscopy within broad but well‐defined limits of applicability. This research was supported by the Spanish Ministry for Science and Innovation (BFU2009–07595), the European Research Council (Grant Agreement 242993) and the National Institutes of Health (R01HL102373, R01HL107561).
Effect of BAP and ZEA Growing Period on Multiplication of Eucalyptus sp. in RITA® Bioreactor
Authors: Hyodo Vivian Cristina Costa Castilho , Runho Daniela Scacci , Oliveira Mila Liparize , Ferreira Alexandre Oliveira
Published: June 2021

The objective of this study was to evaluate the effect of different cultivation periods with 6‐benzylaminopurine (BAP) and zeatin (ZEA) in bioreactor RITA® on multiplication rate, shoots physiological vigor and hyperhydricity rate. The explants used were apical buds of a Eucalyptus grandis × E. urophylla clone established in vitro and cultured in bioreactors RITA® in four different exposure periods (0 to 10, 10 to 20, 20 to 30 and 0 to 30 days) to the growth regulators BAP and ZEA at 0.5 μM in MS culture medium. Explants cultured in BAP presence showed a higher multiplication rate of new shoots compared to cultured with ZEA. The 0 to 30 days cultivation period in the presence of BAP promoted greater hyperhydricity, shoot number and percentage of elongated shoots. Explants cultured on ZEA presence in the same cultivation period were more healthy and vigorous due to the lower hyperhydricity rate. These results demonstrate the difference in growth and quality of the crop due to the type of cytokinin used in vitro culture.
Differential bacterial invasion in normal and cancer hepatocytes
Authors: Hong Jung Woo , Kim Mina , Song Sukhyun , Shin Jennifer Hyunjong
Published: June 2021

Despite numerous demonstrations of bacteria targeting and reducing tumor by inducing necrosis in several animal studies, the actual mechanisms of bacteria targeting and invading into cancer remain unclear. In this study, the differential bacterial invasion and necrosis in cancer and normal hepatocytes were analyzed using Salmonella typhimurium. Observations of bacteria exhibiting selective targeting for cancer hepatocytes (HepG2) over normal hepatocytes (THLE‐2) were made initially with a novel microfluidic platform. When cells were infected directly, cancer cells were more vulnerable to infection than normal cells, resulting in much lower survival after 90 minutes. Cancer cells featured more prominent alterations in cytoskeletal actin, indicating the importance of actin related proteins in invasion. Since myosin II plays critical roles in regulating actin filaments, we treated cells with blebbistatin and calyculin A to inhibit and enhance the activity of myosin II, respectively. Blebbistatin treatment greatly enhanced cell survival while calyculin A lowered the survival of cells against infection, signifying myosin II activity in bacterial invasion. Western blot analysis confirmed higher intrinsic level and activity of myosin II in HepG2 than THLE‐2 suggesting that the vulnerability of HepG2 against bacterial infection depends on the inherently high level of myosin II and its activity.
Supplementation with phosphatidylcholine during suckling improves the immune response of the offspring
Authors: Lewis Erin Diane , Goruk Susan , Curtis Jonathan M , Jacobs René L , Field Catherine J
Published: June 2021

Choline is essential during suckling for the development of the offspring. In the Alberta Pregnancy Outcomes and Nutrition cohort, the major forms of dietary choline were phosphatidylcholine (PC) and free choline. These forms are metabolized differently and this study was conducted to determine the effect of different forms of maternal dietary choline on immune development in the suckled offspring. Lactating dams (n=5/group) were randomized to nutritionally complete, isocaloric, high fat (20% w/w) diets of similar fatty acid compositions, containing 1.0 g/kg choline as free choline (C) or PC (PC) and 2 pups from each litter were pooled to assess the effect of diet on splenocyte function. Diet did not affect growth or the number and relative % of T or B cells in spleen. PC pups had a higher (1.56X) proportion of activated cytotoxic T cells (CD8+CD71+) compared to C pups (p<0.05). When stimulated ex vivo with Concanavalin A, cells from PC pups produced more IL‐2 (1.7X), IL‐6 (2.6X), and IFN‐γ (2.4X) compared to C pups (p<0.05). Cells from PC pups produced more IL‐6 (2.1X) and TNF‐α (1.4X) compared to C pups after stimulation with lipopolysaccharide (p<0.05). Findings suggest that providing choline in the maternal diet as PC promotes T cell maturation and function in the offspring during a critical period of immune development.

Grant Funding Source: WCHRI Studentship, NSERC, Alberta Egg Producers
The effect of Adiponectin on Intestinal Fibroblasts
Authors: Williams Cayla Marjorie , Fayad Raja , Anderson Meghan Katherine , Reaves Titus A.
Published: June 2021

Intestinal fibrosis is a common complication of inflammatory bowel disease ((IBD), dysregulated intestinal inflammation with an unknown etiology). During fibrosis, over‐active fibroblasts produce aberrant collagen, which leads to the formation of fistulas, intestinal strictures, and bowel obstructions. Adiponectin (APN), a member of the C1q/Tumor necrosis factor related proteins (CTRP), is a cytokine that is released by adipocytes and is reported as having a dual role in metabolism and immunity. Interestingly, intestinal fibrosis patients have increased levels of APN and IL‐6 (inflammatory, pro‐fibrotic cytokine). For this study, we examined the effect that APN exerts on intestinal fibroblasts. Results show that the expression of the APN receptor on fibroblasts was varied with treatment of IL‐6, IL‐10 (anti‐inflammatory cytokine) and interferon‐γ (inflammatory cytokine), and co‐immunoprecipitation results reveal that the APN receptor is linked to CD11b on the fibroblast surface. Furthermore, cellular treatment with APN caused increased adhesion of fibroblasts to type I collagen and facilitated the release IL‐6 in a concentration dependent manner. Results identify a mechanism that is initially mediated by APN, and potentially may lead to a hyper fibro proliferative‐phenotype indicative of fibrosis. This study highlights APN as a potential target molecule in the treatment of intestinal fibrosis.
CCN1/Cyr61 regulates Sonic Hedgehog Signaling through Activation of Notch‐1 in Pancreatic Carcinogenesis: A Novel Targeting Pathway for Pancreatic Cancer Therapy
Authors: Haque Inamul , De Archana , Majumder Monami , Mehta Smita , McGregor Douglas , Banerjee Sushanta K , Van Veldhuizen Peter , Banerjee Snigdha
Published: June 2021

CCN1 is a member of the CCN family of growth factors. It is associated with the development of various cancers including pancreatic ductal adenocarcinoma (PDAC). Previously we found CCN1 as an important factor in determining PDAC aggressiveness as it promotes epithelial to mesenchymal transition, tumor stemness, in vitro migration and tumorigenicity in xenograft model, possibly through the regulation of multiple miRNAs that are known to link with the progression of cancers and survival and the maintenance of cancer stem cells. CCN1 mRNA and protein expression was intensified with disease progression. However, biochemical activity and the molecular targets of CCN1 in pancreatic cancer cells are unknown. Our objective was to see whether CCN1 regulates the Sonic Hedgehog (SHh) signaling pathway, which is associated with the PDAC progression and poor prognosis. SHh regulation by CCN1 in pancreatic cancer cells is mediated through the active Notch‐1. Notably, active Notch‐1is recruited by CCN1 in these cells via the inhibition of proteasomal degradation results in stabilization of the receptor. Moreover, the functional role of CCN1 could be mediated through the interaction with the αvβ3 integrin receptor. These extensive studies propose that targeting CCN1 can provide a new treatment option for patients with pancreatic cancer since blocking CCN1 simultaneously blocks Notch1 and SHh signaling pathways.

This work was supported by VA Merit Review Grants (Sushanta K. Banerjee and Snigdha Banerjee)
Epithelial wound repair: insights into the multifaceted roles of Annexin A1
Authors: Leoni Giovanna , Neumann Philipp‐Alexander , Alam Ashfaqul , Hilgarth Roland S , Lambeth David J , Kusters Dennis , Reutelingsperger Chris , Perretti Mauro , Parkos Charles A , Neish Andrew S , Nusrat Asma
Published: June 2021

Pathologic states associated with intestinal injury result in compromised mucosal barrier function. The intestinal epithelial sheet rapidly migrates to reseal wounds and re‐establish the mucosal barrier. We report that the calcium dependent phospholipid binding protein Annexin A1 (AnxA1) is a proresolving mediator that signals via formyl peptide receptor (FPR) and NADPH oxidase‐1 (Nox1) to promote wound recovery. A therapeutic effect of exogenous AnxA1 administration on murine intestinal epithelial wound repair was observed in WT mice but not in mice lacking Nox1 in the intestine (Nox1−/−IEC). Additionally, AnxA1 protein was up‐regulated in murine intestinal wounds. In vitro studies demonstrated that AnxA1 was released into the supernatant of migrating epithelial cells. Ultracentrifugation of cell supernatants identified cleaved AnxA1 (as a 37/33kDa doublet) in a membrane fraction consistent with its release in microparticles, small (<1 μm) heterogeneous structures derived from shedding of cell membranes. Incubation of wounded epithelial cells with microparticles containing AnxA1 promoted wound closure. These findings elucidate a mechanism by which intracellular AnxA1 is cleaved and released from the epithelium within microparticles to subsequently signal via FPR and Nox1 to promote mucosal repair.
γ‐Cytoplasmic Actin Modulates Epithelial to Myofibroblast Transition in Lung Epithelial Cells
Authors: Baranwal Somesh , Gupta Pooja , Ivanov Andrei I
Published: June 2021

Epithelial to myofibroblast transition (EMyT) plays an important role in tumor progression and tissue fibrosis. EMyT is accompanied by dramatic changes in the organization of the actin cytoskeleton, although the roles of different cytoskeletal proteins in modulating such transition remain poorly understood. In the present study, we observed that siRNA‐mediated knock‐down of γ‐ cytoplasmic actin (γ‐CYA) but not β‐cytoplasmic actin induced EMyT in A549 lung epithelial cells. The EMyT was manifested by increased expression of α‐smooth muscle actin, L‐caldesmon and other contractile proteins along with disruption of focal adhesions and inhibition of cell migration. Induction of EMyT in γ‐CYA‐depleted cells depended on activation of a transcriptional regulator, Serum Response Factor and nuclear translocation of its coactivators, MRTF‐A and MRTF‐B. Furthermore, immunoprecipitation analysis revealed selective interactions of MRTFs with γ‐CYA. Finally, pharmacological inhibition of Rho kinase attenuated induction of EMyT in γ‐CYA‐depleted cells. Together, this study identifies γ‐CYA as a potent suppressor of EMyT in epithelial cells that may play roles in regulating tumor progression and tissue fibrosis. Supported by NIH grant DK083968 and DK084953 to Andrei I Ivanov
Novel role of Suppressor of Cytokine Signaling 3 in regulating LPS‐induced Matrix Metalloproteinase 13 gene expression in osteoblasts
Authors: Gao Anqi , Kantarci Alpdogan , Gao Hongwei , Van Dyke Thomas
Published: June 2021

Suppressors of cytokine signaling 3 (SOCS3) is a key regulator of cytokine signaling in macrophages and T cells. Although SOCS3 seems to contribute to the balance between the pro‐inflammatory effects of IL‐6 family of cytokines and anti‐inflammatory signaling of IL‐10 by regulating gp130/Jak/Stat3 signal transduction, how SOCS3 controls the downstream effects of TLR4 are largely unknown and current data are controversial. Furthermore, very little is known regarding its function in cells other than myeloid cells and T cells. The objective of this study is to determine the function of SOCS3 in osteoblast inflammatory responses. We examined the effects of SOCS3 on E.coli LPS‐induced gene expression of matrix metalloproteinase 13 (MMP‐13), one of central regulators of bone resorption, by over‐expressing SOCS3 protein in osteoblasts via transient transfection and evaluated the effects by quantitative real‐time PCR, luciferase assay, and western blotting. We report for the first time that LPS stimulation of osteoblasts induces the transcriptional activation of MMP‐13. Importantly, we demonstrate that SOCS3 expression leads to a significant decrease of LPS‐induced MMP‐13 expression in both primary murine calvariae osteoblasts and a mouse osteoblast‐like cell line, MC3T3‐E1. Our findings implicate SOCS3 as an important regulatory mediator in bone inflammatory diseases by targeting MMP‐13.