bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism of Reactive Dilation in Soleus Feed Arteries
Authors: Gray Eric , Carter Matthew R. , Jasperse Jeffrey L.
Published: June 2021

We have previously shown that reactive dilation of isolated resistance arteries is dependent on both magnitude and duration of pressure reduction. We sought to determine the mechanism for these differences. Rat soleus feed arteries (n=54) were isolated, cannulated, and intraluminal pressure was set at either 65 or 115 cmH2O. Intraluminal pressure was reduced to 14 cmH2O from either baseline pressure for 1 or 2 min and returned abruptly to baseline pressure, causing a temporary dilation lasting 1–2 minutes. Increasing either duration or baseline pressure increased the magnitude of dilation (1m‐65 = 22.9±2, 1m‐115 = 32.2±2.4, 2m‐65 = 29±2.1, 2m‐115 = 45.1±2.8 max % dilation). Inhibition of nitric oxide production (300 μM L‐NNA) or inhibition of mechanosensitive cation channels (50 μM gadolinium) both failed to alter reactive dilation. Likewise, inhibiting depolymerization of actin filaments (100 nM jasplakinolide) did not reduce reactive dilation. Finally, neither inhibition of tyrosine kinase activity (5 μM genistein) nor inhibition of large Ca2+ activated K+ channels (BKCa) (5 μM iberiotoxin) reduced reactive dilation. These data indicate that reactive dilation of soleus feed arteries is not dependent on nitric oxide, mechanosensitive cation channels, actin depolymerization, tyrosine‐kinase activity, or BKCa. The mechanism responsible for reactive dilation of soleus feed arteries remains unknown.
Junctophilin 2 is reduced in the border zone 3 hours after a myocardial infarction in sheep heart
Authors: Ingalls Christopher , Baumann Cory , Gahlot Nidhi , Santamore William , Gorman Joseph H , Gorman Robert C
Published: June 2021

Eccentric contraction‐induced injury of skeletal muscle is associated with weakness stemming in large part from impaired voltage‐gated sarcoplasmic reticulum Ca2+ release that appears to be mediated by the loss of the triadic protein junctophilin (JP). After a myocardial infarction (MI), the myocytes in the region around the MI (i.e., border zone) appear to be lengthened while activated (i.e., eccentric contraction). If injured by eccentric contractions, these myocytes may contribute to abnormal contractile mechanics, myocardial remodeling and failure. The purpose of this study was to test the hypothesis that JP2 content is reduced in the border zone after an MI in sheep heart. Sheep left anterior descending and second diagonal coronary arteries were ligated for 1 hr followed by 2 hr of reperfusion. Immunoblotting was used to measure JP2 and tubulin content in left ventricular wall samples taken from the infarct (n=5), border zone (n=5), and control remote (n=5) regions. Three hours after inducing the MI, JP2/tubulin ratio is significantly (P<0.05) reduced in infarct (0.28±0.46) and border zone (0.58±0.56) myocardium compared to control remote region (1.52±0.29) of the heart. MI results in the preferential loss of JP2 in the border zone within 3 hours of the MI and may contribute to weakness and abnormal strain in the left ventricular myocardium. .
Conditional inactivation of the splicing regulator Tra2[beta] shifts myosin phosphatase isoforms and enhances smooth muscle sensitivity to cGMP‐mediated relaxation
Authors: Bhetwal Bhupal , Fu Kang , Mende Ylva , Perrino Brian , Wirth Brunhilde , Fisher Steven
Published: June 2021

Based on patterns of expression, correlative physiologic studies, and in vitro mini‐gene splicing assays, we have proposed that 1) the tissue‐specific splicing of Myosin Phosphatase Targeting subunit (MYPT1) 3′ alternative exon (E23), by coding for isoforms that contain or lack a C‐terminal Leucine zipper (LZ) motif, determines smooth muscle sensitivity to NO/cGMP signaling and 2) that the tissue‐specific splicing of this exon is controlled by Transformer 2β (Tra2β). To test this model in vivo we crossed SM22Cre and Tra2β flox mice for conditional inactivation of Tra2β specifically in smooth muscle cells (cKO). Homozygous mice (Cre+//f/f) were non‐viable prior to birth. In mature heterozygous mice (Cre+//f/+) small intestinal smooth muscle there was a significant loss of MYPT1 E23 splicing (WT 82±5% vs cKO 25±7%,p<0.01) associated with the expected shift to the MYPT1 LZ+ isoform. The cKO muscles generated greater total force (AUC) under isometric conditions when activated ex vivo with Carbachol (1 μM) (cKO 105+25 vs WT 63+11; p<0.01, n=6), and were more sensitive to 8‐Br‐cGMP at all concentrations tested (50–300 μM; maximum inhibition of force production: cKO 68+2% vs WT 51+3%, p<0.01, n=3). We conclude that tissue‐specific splicing of MYPT1 E23 is highly sensitive to Tra2β gene dosage. The regulated splicing of MYPT1 E23, and likely other exons, tunes smooth muscle tissue‐specific contractile function and sensitivity to NO/cGMP signaling.

This work was supported by NIH grants RO1 HL‐66171, RR08751
Bisphenol A decreases BK channel expression in rat aorta via genomic mechanisms
Authors: Asano Shinichi , Fancher Ibra Seaphus , Dick Gregory M
Published: June 2021

Bisphenol A (BPA) is an estrogenic endocrine disruptor associated with a variety of pathologies that have raised public health concerns. Epidemiological studies show a relationship between urinary BPA levels and cardiovascular diseases, but the molecular actions of BPA on the cardiovascular system remain largely unknown. Estrogen regulates the expression of large conductance voltage/Ca2+‐activated K+ (BK) channels; however, effects of BPA on BK channel expression are unknown. We tested the hypothesis that BPA regulates BK channel expression though genomic mechanisms involving nuclear estrogen receptors (ER). Rat aortae were harvested and placed in tissue culture for 48–72 hour treatment with BPA. BK channel expression was determined by RT‐PCR, Western blot, and whole‐cell patch clamp. BPA decreased the expression of BK α subunit mRNA and protein. Penitrem A‐sensitive BK current was reduced in cells from BPA‐treated aortae. The effect of BPA to reduce BK channel mRNA, protein, and current was blocked by ICI 182,780, an ER antagonist. These data suggest that BPA decreases BK channel expression via nuclear ER and may represent one mechanism by which BPA exposure is linked to cardiovascular disease. Supported by T‐32 HL‐090610.
The repeated‐bout effect is compromised in the tibialis anterior muscles of mdx mice
Authors: McBride Todd A. , Reynolds Ricco
Published: June 2021

The purpose of this study was to test the hypothesis that skeletal muscles from mdx mice would have a reduced ability to adapt to eccentric muscle contractions (EC). Tibialis anterior (TA) muscles from male C57BL/6N and mdx mice 8–10 weeks of age were exposed to either a single or multiple bouts of EC separated by 14 days. Serum creatine kinase (CK) values were measured prior to EC, and immediately, 24, and 48 hours post exercise. Resting membrane potentials (RMP) were also measured immediately following a single or multiple bouts of EC. CK values were significantly greater in mdx mice compared to C57BL/6N mice prior to performing EC. Immediately following a single bout of EC, CK values were significantly greater than pre‐exercise in both C57BL/6N and mdx mice. At 24 and 48 hours neither group was different than their respective pre‐exercise values. Immediately following a second bout of EC, CK values were not different in C57BL/6N mice, but were significantly elevated in mdx mice when compared to pre‐exercise values. Neither group was different from pre‐exercise values at 24 and 48 hours after the second bout of EC. Measurement of RMP resulted in a similar trend. Both groups were significantly depolarized following a single bout of EC. After a second bout of EC cells from C57BL/6N mice were significantly less depolarized than following a single bout, while mdx muscles had a similar significant level of depolarization as measured after a single bout of EC. Together these results indicate a significant reduction of the repeated‐bout effect in TA muscles from mdx mice.
The truth behind pre‐exercise drinks: males versus females
Authors: Anderson Justin Michael , Buryanek Bryce , Larson Dane , Bunker Aaron
Published: June 2021

It was hypothesized that the effects of pre‐exercise drinks on forearm skeletal muscle performance differ between the sexes, independent of arm. Healthy males (n=6; 22±0 years old) and females (n=6, 21±1 years old) performed a maximal hand‐grip exercise in either arm 30‐minutes after consuming different pre‐exercise drinks including: water (the control), Red Bull™, and N.O. Shotgun™. Subjects participated in three different experimental sessions over the course of 3‐weeks, a different drink each session in random order, with a 6‐day rest period between each session to allow for the subjects to fully recover from each workout. A combination of Powerlab‐26T, LabChart™, and a hand dynamometer were used to measure time to fatigue (TTF) in each subject. Mean male Body Mass Index (21.0±0.2kg/m2) did not differ from female (21.2±0.62kg/m2) values. Male right forearm girth (25.5±1.5cm) did not differ from female right forearm girth (26.0±1cm). TTF results showed that consumption of Red Bull or N.O. Shotgun did not differ between the sexes for either arm (p<0.05). It is concluded that Red Bull and N.O. Shotgun do not have significant differential effects on forearm skeletal muscle performance between the sexes. This work was supported by: Morningside College Ver Steeg Funds.
Loss of skeletal muscle oxidative phenotype and endurance in mild‐to‐moderate COPD
Authors: Slot Ilse , van den Borst Bram , Hellwig Valéry , Kelders Marco , Schols Annemie , Gosker Harry
Published: June 2021

Loss of skeletal muscle oxidative phenotype (OXPHEN) and subsequent impaired muscle endurance are hallmarks of severe COPD, but less is known regarding these in mild‐to‐moderate COPD. We studied muscle OXPHEN in relation to muscle endurance in mild‐to‐moderate COPD patients (mean FEV1 58±16 %pred).

Quadriceps biopsies were collected from 29 clinically stable mild‐to‐ moderate COPD patients and 15 controls to analyze fiber type distribution and gene expression levels of oxidative and glycolytic markers. Quadriceps strength and fatigability were determined by peak torque and temporal decline in torque respectively, during 30 maximal voluntary isokinetic leg extensions.

Compared to controls, COPD patients had significantly lower fiber type I proportions, oxidative PGC1α and MyHC I mRNA levels, and higher glycolytic PFKM expression. Muscle strength was not different, but endurance was reduced in COPD and correlated with gene expression of PGC1α and MyHC I. A trend was observed with % type I fibers. No markers correlated with FEV1.

To our knowledge this is the first time that loss of muscle OXPHEN associated with impaired muscle endurance is observed in patients with mild‐to‐moderate COPD. This supports the indication for and efficacy of lifestyle intervention targeting muscle function in less advanced COPD as previously proven in a RCT (Van Wetering et al. Thorax 2010).

Performed within TI Pharma T1‐201.
Arterial PCO2 (PaCO2) can be accurately estimated using end‐tidal PCO2 (PETCO2) during rest and exercise in obese subjects
Authors: Bernhardt Vipa , Straub Allison M , Lavin Kaleen M , Lorenzo Santiago , Babb Tony G , Zavorsky Gerald S
Published: June 2021

Obesity affects lung function, gas exchange and imposes mechanical ventilatory limitations during exercise that could disrupt the predictability of PaCO2 from PETCO2. 22 women (37 yrs, 50 BMI) and 16 men (40 yrs, 51 BMI) underwent a ramped cardiopulmonary exercise test to exhaustion. PETCO2 was recorded from expired gases simultaneously with arterial blood gases (radial arterial catheter) at rest, at minute 4 (submax) and at peak exercise. To estimate PaCO2 from PETCO2 and tidal volume (VT), the equation derived by Jones et al. (JAP 1979) was used: PJCO2 = 5.5 + 0.9PETCO2 – 2.1VT.

Using independent t‐tests, no significant differences were found between men and women in PETCO2 or PaCO2 values at rest, submax or peak exercise, and were combined in further analyses. Paired t‐tests revealed that PETCO2 was not different from PaCO2 at rest (PETCO2 = 37.1 mmHg vs PaCO2 = 37.6 mmHg, p = 0.14). However, at submax and peak exercise PETCO2 was higher than PaCO2 (submax: 42.4 mmHg vs 40.0 mmHg, p < 0.001; peak: 39.9 mmHg vs 37.6 mmHg, p < 0.001). PJCO2 was not different from PaCO2 (submax: p = 0.65; peak: p = 0.07).

Although obesity places a substantial load on the respiratory system, these obese individuals exhibited normal values in terms of CO2 clearance (i.e. PETCO2 – PaCO2). PJCO2 estimates corresponded more closely with PaCO2 than PETCO2 during exercise.

Supported by HL096782, King Charitable Foundation Trust.
Effects of Spinal Cord Section on Inspiratory Pressure Generation During High Frequency Spinal Cord Stimulation (HF‐SCS)
Authors: Kowalski Krzysztof E , DiMarco Anthony F
Published: June 2021

Objective

HF‐SCS is a novel and more physiologic method of inspiratory muscle activation which involves activation of spinal cord pathways. The specific pathways by which inspiratory motoneurons are activated by this method however are unknown. The aim of the present study was to evaluate the potential role of upper cervical inspiratory neurons on the observed responses.

Methods

In 6 anesthetized and spinalized (C1 level) dogs, HF‐SCS was applied at T2 level. Airway pressure generation (P) was monitored as an index of the degree of inspiratory muscle activation before and following sequential spinal sections at the C4 (to eliminate upper cervical propriospinal neurons) and subsequently the C8 level.

Results

During HF‐SCS, P at FRC was 68±6 cmH2O. Sequential bilateral dorsal columns (DC), lateral funiculi (LF) and complete section (CS) at C4, resulted in no significant changes in P (69±5, 67±5 and 65±7 cmH2O respectively, NS). While DC section at C8 resulted in no changes in P (63±5 cmH2O), LF section resulted in significant reduction in P to 18±3 cmH2O (p<0.05). Subsequent CS resulted in no further reduction in P (14±1 cmH2O, NS).

Conclusion

During upper thoracic HF‐SCS, activation of the phrenic motoneuron pools does not involve upper cervical propriospinal inputs. The phrenic motoneuron pools are activated via spinal pathways located bilaterally in the lateral funiculi.

Support: NIH‐NINDS (R01NS064157).
Changes in central respiratory patterns and activity following acute lung injury in the in situ rat preparation
Authors: Zaylor Abigail Rose , Nethery David , Hsieh Yee-Hsee , Dick Thomas E , Jacono Frank J
Published: June 2021

We have quantified changes in the variability of the respiratory patterns after acute lung injury (ALI) and reported increased respiratory rate and increased measures of linear and nonlinear variability by using Mutual Information (MI) and Nonlinear Complexity Index (NLCI). These changes are associated with lung and brainstem inflammatory responses. We hypothesize that changes in respiratory pattern after ALI are, in part, mediated centrally. To test our hypothesis we administered either bleomycin (0.5U in 50 μL of saline, n=9) or saline (50 μL, n=9) intratracheally to rats (Sprague‐Dawley, Harlan, P21–22). After 7d, central respiratory patterns were measured by recording the left phrenic, hypoglossal and vagal nerve activities using a perfused in situ preparation. Comparing in situ preparations from bleomycin to saline‐treated rats, bleomycin‐treated rats exhibited: 1) higher burst frequency (26 ± 4 vs. 20 ± 4 bpm, p=0.01), 2) lower coefficient of variation (p=0.01) integrated vagal nerve activity had 3) greater MI (p=0.01) and NLCI (p=0.01) and 4) phrenic and vagal nerve activities displayed increased early inspiratory activity. Fundamental changes in the respiratory patterns evoked by ALI persisted in the absence of vagal feedback from lung or blood chemistry indicating that central mechanisms are involved in generating the respiratory pattern after 7d of ALI. Supported by HL 087377, VA Research Service
Knock‐down of Vmat2 in Mouse Right Striatum and Physical Activity
Authors: Schmitt Emily E. , Ferguson David P. , Lightfoot J. Timothy
Published: June 2021

In spite of significant evidence that daily activity is controlled primarily by genetic mechanisms, there is little data available regarding the mechanisms of action. We investigated the role of vesicular monomine transporter type 2 (Vmat2) in regulating wheel‐running activity in mice and to determine the time course of gene silencing using vivo‐morpholinos. All aspects of this study were conducted in conformance with the FASEB Statement of Principles for the use of animals in research and education. We randomly assigned 24, 8 week old male C57Bl/6J mice to one of two groups: an access to running wheel group and a fixed running wheel group. All animals received a tail‐vein injection (11mg/kg) of Vmat2‐targeted vivo‐morpholino for three consecutive days. One mouse from each group was sacrificed each day. Western Blotting was used to track efficacy of gene knock‐down. Vmat2 expression decreased with morpholino injection, but no differences were found between wheel and fixed wheel groups (p=0.29). Physical activity was initially decreased after Vmat2 knock‐down (days 1–5), with activity on days 6–10 significantly increasing (p=0.0016) toward baseline values. In conclusion wheel exposure did not affect efficacy of Vmat2 knock‐down. Further, transiently silencing Vmat2 resulted in a transient decrease in physical activity suggesting that Vmat2 may play a role in regulating activity.
Shear‐responsive miR‐155 Regulates Endothelial Cell Phenotype and Function
Authors: Weber Martina , Kim Sinae , Patterson Nicole , Searles Charles D.
Published: June 2021

In endothelial cells (ECs), unidirectional shear stress (USS) changes gene expression and promotes an atheroprotective cell phenotype, whereas low or oscillatory shear stress induces an atherogenic phenotype. We found that miR‐155 expression was increased 4 fold in response to USS, compared to oscillatory shear stress conditions. Transfection of miR‐155 mimic into human ECs dramatically altered the actin cytoskeleton organization. ECs overexpressing miR‐155 had less F‐ actin and less focal adhesions, indicated by a decrease in Vinculin and p‐FAK protein (p=0.016 and p=0.018). Furthermore, miR‐155 suppressed two key regulators of the EC cytoskeleton: RhoA (decreased 75%) and myosin light chain kinase (MYLK, decreased 40%). These miR‐ 155 mediated changes were associated with less EC migration (p=0.0106) and proliferation (p=0.0002). Also, ECs overexpressing miR‐155 showed less monocyte adhesion compared to control cells (p=0.0002). In vivo, miR‐155 expression was increased in the atheroprotected thoracic aorta (p=0.0012), where shear stress is unidirectional, compared to the atherosusceptible lower curvature of the aortic arch, where shear stress is low. In conclusion, we demonstrate that miR‐155 expression is regulated by shear‐stress in vitro and in vivo and suggest that miR‐155 induced changes in RhoA and MYLK expression are important for maintaining an atheroprotective phenotype in human ECs.
Dynamics of the cecal microbial community of an extreme hibernator, the arctic ground squirrel
Authors: Stevenson Tim , Buck Loren , Quinlan Brian , Duddleston Khrystyne
Published: June 2021

Arctic ground squirrels (Urocitellus parryii) acquire most of their necessary energy stores (primarily fat, 5 to 45% increase) to survive hibernation during the 3 weeks preceding immergence. Studies in humans and mice show the gut microflora of obese individuals is efficient in extracting energy from carbohydrates and promotes host storage of triglycerides into adipose tissue, suggesting the gut microbiota of arctic ground squirrels may play an important role in pre‐hibernation fattening.. In order to study changes in gut microflora, cecal samples were collected from captive‐born juvenile squirrels at 4 time points (n=10) from weaning to hibernation. Mean squirrel mass increased linearly with age (R2= 0.9652), while mean abdominal white fat mass increased exponentially (R2 = 0.9982). Cecal content peaked at 6 weeks post‐weaning (15g ± 4.75). The percent live cells increased linearly from 63.31% ± 3.84 to 80.04% ± 5.00 throughout the active season (R2= 0.9989), while percent dead and injured cells decreased linearly, 28.77% ± 3.93 to 17.14% ± 5.67 and 7.87% ± 1.64 to 2.76% ± 0.84, respectively (R2= 0.9804 and 0.9899, respectively). These results suggest that microbial cell viability increases throughout development and pre‐hibernation fattening. Additional analyses conducted includes microbial community diversity using 16s rDNA genes, and short chain fatty acid analysis to investigate microbial activity.
Folate modulates adipocyte promoter methylation and lipid filling and release
Authors: Gouffon Julia S , Johnstone Megan , Zemel Michael B
Published: June 2021

Nutritional inputs may modify gene promoter methylation and thereby affect adipocyte metabolism. We differentiated 3T3L1 adipocytes under low, standard and enhanced folate levels followed by maturation under similar treatments plus the methyl donor S‐adenosylmethionine (SAM) and methylation inhibitor, 5‐aza‐2‐deoxycitidine (2DC). Folate exposure during differentiation dose‐dependently decreased triglyceride accumulation, lipolysis and proliferation (p<0.001) while folate exposure during maturation dose‐dependently increased triglyceride accumulation and lipolysis (p<0.001). Adipocytes differentiated under low folate conditions showed increased mRNA levels of key metabolic genes after exposure to high folate conditions during maturation ; hormone sensitive lipase (Lipe, +54.25%), fatty acid synthase (Fasn, +288%), glucose transporter 4 (Glut4,+141%), leptin (Lep, +450%). Adipocyte genomic DNA was hybridized against Nimblegen whole genome CpG promoter arrays and RNA on Affymetrix Mouse arrays. Low folate exposure during maturation decreased promoter methylatation in Lipe and carboxylesterase (CES) with increased gene expression relative to standard conditions (1.17 & 4.14 FC respectively). Thus, adipocyte exposure to methyl donors during and following differentiation modulates lipid accumulation, and low folate during differentiation may promote lipid filling.

Grant Funding Source : Internal Award
The fetal programming of dietary fructose and saturated fat on hepatic quercetin glucuronidation in rats
Authors: Chen C-Y. Oliver , Bryant Nyssa , Blumberg Jeffrey , Serra Aida
Published: June 2021

Polyphenol metabolites generated by phase II enzymes in vivo are bioactive. However, data on the impact of diet and fetal programming on the activity of microsomal UDP‐glucuronosyltransferase (UGT) are limited. We examined the effect of parental exposure to a diet high in fructose and saturated fat (SFF) 1 mo before conception and during gestation and lactation on in vitro hepatic UGT activity toward quercetin (Q) in parent (F0) and offspring (F1) rats. The SFF diet included 9.9% coconut fat, 0.5% cholesterol, 30% fructose, and 30% glucose and the control diet (C) 11% corn oil and 60% glucose. After weaning, all offspring were fed C diet for 12 wk. UGT activity was determined with 30 μM Q and 12.5 μg protein in 100 μL after a 15‐min incubation at 37°C. There was a sex and diet interaction on production rate of 3’‐ (3’‐OH), 4’‐ (4’‐OH), 7‐Q‐glucuronide (7‐OH), and total Q glucuronide (TQG). In F0 females, the production rate of 3’‐OH and TQG was decreased by 29 and 35% by SFF as compared to C (P ≤0.05). SFF led to a 22% difference in 4’‐OH production rate between females and males of the F0. In F1, the production rate of 7‐OH in C females was 59% larger than C males, but not different in SFF rats. Thus, high dietary fructose and saturated fat may decrease UGT activity toward Q in female rats and in utero exposure to this diet may decrease UGT activity in female offspring, possibly via epigenetic mechanisms.
The reaction of HOCl and cyanocobalamin: corrin destruction and the liberation of cyanogen chloride
Authors: Maitra Dhiman , Byun Jaeman , Souza Carlos Eduardo A. , Banerjee Jashoman , Andreana Peter R. , Pennathur Subramaniam , Abu-Soud Husam M.
Published: June 2021

Elevated hypochlorous acid (HOCl) has been associated with the development of several pathological conditions such as inflammation, heart disease, and cancer through its ability to modify different biomolecules. HOCl is a potent oxidant generated by the myeloperoxidase‐hydrogen peroxide‐chloride system. Recently, we have shown that higher levels of HOCl can cause heme destruction and free iron release from hemoglobin and erythrocytes. Our current finding extends this work and demonstrates the ability of HOCl to mediate the destruction of metal‐ion derivatives of tetrapyrrole macrocyclic rings, such as cyanocobalamin (Cobl), a common pharmacological form of vitamin B12. Cobl is a water‐soluble vitamin that plays an essential role as an enzyme cofactor and antioxidant, modulating nucleic acid metabolism and gene regulation. It is widely used as a therapeutic agent and supplement because of its efficacy and stability. In this report, we demonstrate that while Cobl can be an excellent antioxidant, exposure to high levels of HOCl can overcome the beneficial effects of Cobl and generate proinflammatory reaction products. Our rapid kinetic, HPLC and mass spectrometric analyses showed that HOCl can mediate corrin ring destruction and liberate cyanogen chloride through a mechanism that initially involves α‐axial ligand replacement in Cobl to form a chlorinated derivative, hydrolysis, and cleavage of the phosphonucleotide moiety. The susceptibility of Cobl to HOCl mediated degradation was compared with other vitamin B12 derivatives. Taken together, this is the first report of the generation of toxic molecular products through the interaction of Cobl with HOCl.

Grant Funding Source : NIH
Predictors of Performance in Anatomical Sciences Courses: What Really Matters?
Authors: Lufler Rebecca S.
Published: June 2021

The purpose of this study is to determine if factors previously related to learning in medical school courses predict performance in anatomical sciences courses. Data was collected from first‐year medical students at Tufts University School of Medicine (N= 119). A survey, Mental Rotations Test, and VARK learning preferences inventory were given to students at the beginning of year 1. Course scores were collected at the end of Year 1. Predictor variables included: gender, age, learning style, visual‐spatial ability, MCAT score, and undergraduate major. Outcome variables include final course scores in clinical anatomy (A), head and neck anatomy (HNA), neuroscience (N), and tissue and organ biology (TOB). Statistical analyses were performed using linear regression and standardized beta estimates (relative predictive value of each predictor) were calculated. MCAT scores were predictive of performance in all anatomical sciences courses (A β=0.28, p=0.002; HNA β =0.21, p=0.02; N β =0.31, p=0.001; TOB β =0.30, p=0.002). MRT scores were predictive of performance in HNA but no other courses (HNA β=0.21, p=0.04; A β=0.14, p=0.14; N β=0.04, p=0.7; TOB β=0.05, p=0.6). Other predictors were not significantly predictive of performance in any course. These results demonstrate that although previous studies relate the above predictors to performance in medical courses, only MCAT was consistently predictive of scores in the anatomical sciences.

Grant Funding Source : None
Trends in Neurobiology and Neuroanatomy – Survey Results from North American Dental Course Directors
Authors: Gould Douglas , Hutchins Bob , Atsas Stavros , Lambert H. Wayne
Published: June 2021

The Neurobiology and Neuroanatomy component of The Basic Science Survey Series for Dentistry was conducted to assess how undergraduate dental students are taught neuroscience topics via a Web‐based survey completed by course directors. The purpose of this project was to help dental faculties with curricular planning by establishing what neurobiology and/or neuroanatomy topics are taught, assess the level of faculty involvement in such teaching, and identify other key pedagogical considerations in the dental basic sciences. The response to the survey was impressive from the 67 North American dental programs – 66/67 responding (a 98.5% response rate). The results of the survey indicate amongst other things, that: 1) the use of computer‐assisted instruction has increased; 2) emphasis on clinical topics has increased; 3) reliance on medical school faculty and facilities remains high; 4) a pattern of increased use of integrated curricula among dental schools has emerged; 5) a trend for a decrease in student contact hours is ongoing; and 6) neuroscience educators are aging. These data will provide the framework by which course directors and administrators, in need of curricular information, can make more informed decisions regarding the appropriateness of content, provide guidance in evaluation of their program and help with strategic planning for future endeavors.
Heart making and heart breaking: The molecular circuitry of cardiac development, disease and regeneration
Authors: Olson Eric N
Published: June 2021

Heart disease remains the primary cause of morbidity and mortality in the developed world. A major reason for this is that the adult human heart has limited regenerative capacity following injury. The default healing response in the adult heart involves replacement of cardiac muscle with fibrous, noncontractile scar tissue with consequent loss of contractility. In recent studies, we found that the hearts of neonatal mice can fully regenerate after partial surgical resection, but this capacity is lost early in life. We are currently exploring the molecular underpinnings of the neonatal regenerative response of the heart, with the long‐term goal of discovering combinations of genes and drugs that promote cardiac repair and regeneration. We are also optimizing strategies for reprogramming of cardiac fibroblasts toward a cardiomyocyte cell fate as a means of replacing heart muscle following myocardial infarction. It has recently become apparent that microRNAs play key roles in modulating the response of the heart to injury. We have identified signature expression patterns of microRNAs associated with diverse cardiovascular disorders, including pathological cardiac hypertrophy, heart failure, myocardial infarction, vascular stenosis and angiogenesis. Gain‐and loss‐of‐function studies in mice have revealed striking functions for these microRNAs in numerous facets of cardiac biology, including the control of sarcomere formation, fibrosis, hypoxia, regeneration and myocyte survival. Disease‐inducing microRNAs can be persistently silenced in vivo through systemic delivery of anti‐miRs, allowing for therapeutic modulation of disease mechanisms. Recent advances in understanding the mechanisms of cardiac injury and regeneration as well as strategies for promoting cardiac repair through modulation of intrinsic regenerative mechanisms will be discussed.
Cholesterol Metabolism in Mycobacterium tuberculosis: Chewing Through the Fat
Authors: Nesbitt Natasha Monic , Dubnau Eugenie , Kisker Caroline , Lu Rui , Russell David G , Schäfer Christin , Sherman David R , Smith Issar , Thomas Suzanne T , VanderVen Brian C , Yang Xinxin , Sampson Nicole S
Published: June 2021

New drugs with novel mechanisms of action are required to meet the severe threat to human health posed by the emergence of drug resistant strains of M. tuberculosis (M. tb). M. tb imports and metabolizes host cholesterol during infection, which is critical for the maintenance of M. tb infection. Both the igr operon and fadA5 are required for in vitro growth using cholesterol as a sole carbon source and for full virulence of M. tb in the mouse model of in vivo infection. We have elucidated the function of these genes, their corresponding enzymes and their role in cholesterol metabolism using a combination of transcriptional profiling, bioinformatics, enzymology, biochemistry and metabolic phenotype screening. The 2’propanoyl CoA side chain cleavage intermediate undergoes β‐oxidation catalyzed by FadE28/29, a heterotetrameric acyl CoA dehydrogenase, and Rv3542c/3541c, a heterotetrameric enoyl CoA hydratase; both are encoded by the igr operon. FadA5 is a thiolase that catalyzes side chain cleavage. Ultimately, drug discovery targeting these enzymes will provide inhibitors that attenuate M. tb growth and persistence in vivo.

NIH (AI065251, AI092455, HL53306, S10RR021008 to NSS, A1044856, AI065987 to IS, DK007521 to NMN R01AI067027 to DGR) DOE‐GAANN to STT
MEASURING AND MODELING LIFE‐DEATH DECISIONS IN SINGLE CELLS
Authors: Sorger Peter K. , Lopez Carlos , Flusberg Deborah , Eydgahi Hoda , Bachman John , Sims Joshua , Chen William , Spencer Sabrina , Gaudet Suzanne
Published: June 2021

At the level of single living cells, signal transduction involves remarkably complex biochemistry and great variability from one cell to the next. However, cells achieve exquisite control over fate decisions and subtle mutations that interfere with decision making cause disease. How can variability among genetically identical cells be reconciled with an apparent requirement for precise control over biochemical reactons, what is the impact of non‐genetic variability on the evolution of tumors and what are the implications for drug responses in patients?

I will begin to address these issues with an emphasis extrinsic apoptosis induced by the TNF family member TRAIL. TRAIL is involved in natural immune surveillance of tumors and is also in development as a therapeutic agent. Some TRAIL‐treated human cells die within ~40 min, some only after 12 hr. and yet others live indefinitely. We have explored three explanations for these differences: (i) genetic or epigenetic variation (ii) the involvement of stochastic fluctuations (iii) transient but deterministic differences in cell state. I will illustrate how all three interact on different time scales to determine those aspects of cellular physiology that are highly invariant and those that are variable.

I will also illustrate how studying such problems can be tackled by mathematical analysis of the underlying biochemistry. This involves a continuous interplay between (i) model generation, and variation (ii) calibration of models against experimental data and (iii) model verification through empirical testing of specific molecular hypotheses. I will describe a means to instantiate diverse biochemical hypotheses in networks of differential equations (using a new rules‐based meta‐language PySB) and to rigorously compare predictions to experimental data (via Bayesian parameter estimation). I will also describe strategies for collecting the necessary measurements from single‐cell studies and our attempts to push this into the mouse. I will advance the hypotheses that “systems‐based” approaches are nearing the point that it is possible to replace informal pathway pictures (which dominate molecular biology) with probabilistic mathematical constructs that assign rigorous “degrees of belief” to specific biochemical hypothesis. Finally, I hope to demonstrate that such approaches can be understood and used by a broad community of molecular biologists.
AMPK Control of Metabolic Signaling
Authors: Shaw Reuben
Published: June 2021

One of the central regulators of cellular and organismal metabolism in eukaryotes is AMP‐activated protein kinase (AMPK), which is activated when intracellular ATP production decreases. AMPK has critical roles in regulating growth and reprogramming metabolism, and has recently been connected to cellular processes such as autophagy and cell polarity. As AMPK is activated in response to a variety of stresses, in response to exercise, and by the widely used type 2 diabetes therapeutic metformin. Our laboratory has performed a three‐pronged screen to identify novel substrates of AMPK that may mediate its effects on metabolism and growth control. One of the first such novel substrates we reported was the mTOR‐binding subunit raptor. Phosphorylation of raptor by AMPK is required for the inhibition of mTORC1 and for cell cycle arrest following energy stress. More recently we have found additional connections between AMPK and the control of autophagy, discovering that AMPK directly phosphorylates and activates the ULK1/hATG1 kinase to initiate autophagy. We showed that the AMPK regulation of ULK1 is essential for mitochondrial homeostasis and cell survival under starvation conditions. Collectively, these studies have uncovered novel conserved effectors of LKB1 and AMPK that mediates its role as a metabolic checkpoint coordinating cell growth with energy status. We have also recently uncovered a number of new substrates of AMPK that play key roles in transcriptional control of metabolism, including the Class IIa family of HDACs and the Srebp1 transcription factor. Finally, we are examining whether biguanide compounds including phenformin and metformin, which activate the LKB1/AMPK pathway and are clinically used for treatment of type 2 diabetes, may show utility in the treatment of different mouse models of cancer. The connection between LKB1, AMPK, and mTOR signaling further illustrates molecular connections underlying the development of both cancer and metabolic syndrome.
NMR EBC metabonomic to assess the nutricecutic effect in COPD. A pilot study of oral administration of a curcumin based herbal preparation
Authors: Scapagnini G , Abraham Nader , Davinelli S , de Laurentiis G , Paris D , Melck D , Motta A , Matteo S , Bianco A
Published: June 2021

Nuclear Magnetic Resonance (NMR)‐based metabonomics of EBC is able to separate healthy subjects from patients affected by Chronic Obstructive Pulmonary Disease (COPD), identifying profiles based on cellular oxidative pattern. It is unknown if EBC of COPD patients is altered by treatment of patients with specific exogenous nutrients, and if NMR spectroscopy is able to detect metabolic changes. In this preliminary open label study we evaluated the effect of daily oral administration of high dosage of a curcumin‐based herbal preparation on EBC in a cohort of COPD patients by using NMR spectroscopy. 10 COPD (63.3 ± 7.9) patients were evaluated at baseline and after 12 weeks of oral administration of curcumin once a day, collecting during each visit EBC samples, clinical (breath, cough, sputum and night awakening, BSCN, score) data and spirometry. EBC collected from each patient (at the end of treatment and baseline) were different in NMR spectra profiles and in comparison with spectra of curcumin alone. Notably, a completely different profile is observed in treated patients, with many new resonances appearing in the spectra. Among clinical parameters, BSCN score was 4.9 ± 0.9 at baseline and 7.5 ± 1.0 at time 12 wks, while FEV1 values resulted slightly but not significantly increased at the end of treatment. NMR metabonomic is a sensitive method to explore the nutriceutic effects of antioxidant on EBC in patients of COPD.
A Nationwide Qualitative Assessment of Third and Fourth Year Medical Students’ Views of Childhood Obesity
Authors: Cooke Natalie K. , Raad Alice A. , Alexander De'Ja S. , Lang Brittany A. , Wheeley Jennifer R. , Goodell L. Suzanne
Published: June 2021

Medical professionals need to be prepared to both treat and prevent childhood obesity (CO) and therefore need to understand the multifactorial causes and consequences of CO. In order to qualitatively determine medical students’ views of CO, researchers conducted individual interviews with third and fourth year allopathic and osteopathic medical students across the nation. Researchers asked students to describe the term CO, explain the causes, consequences, prevention, and treatment of CO, and enumerate additional resources they might need to treat and prevent CO. Researchers asked students to give examples from their coursework and rotations. Transcript analysis revealed that students were not confident in educating patients to make dietary and lifestyle changes because this is not taught in medical school. Students who had more knowledge about CO were those who had or were pursuing an additional graduate degree, had volunteered with prevention programs, or had a personal interest in the subject. Many students felt that while they are learning about medical conditions and metabolic disorders, they are not learning the more practical knowledge they need to prevent and treat CO. Medical schools need to provide students both with information about CO and the more skills‐based knowledge to prevent and treat CO, whether through additional time allotted in medical school or through continuing education.

Grant Funding Source : N/A
Cloning, sequencing, and expression of a subset of selenoprotein transcripts in the turkey (Meleagris gallopavo)
Authors: Sunde Roger A , Sunde Gavin R , Sunde Colin M , Sunde Milton L , Evenson Jacqueline K
Published: June 2021

We recently reported that the minimum Se requirement for male turkey poults is 0.3 μg Se/g – three times higher than requirements found in rodent – based on liver and gizzard Gpx4 and Gpx1 activities (Exp Biol Med 235:23 (2010)). We also found that levels and Se regulation of Gpx4 activity and mRNA in turkeys are distinct from those in mammals. Thus we initiated cloning of turkey selenoprotein transcripts as a preliminary step to investigate Se regulation of the full selenoproteome. Using homology of mammalian and G. gallus (chicken) transcripts and proteins, primers for qRT‐PCR were designed to examine the relative expression of selenoproteins in total RNA isolated from 6 turkey tissues (liver, heart, kidney, gizzard, thigh, breast) of an adult male Nicholas‐strain (white) turkey. Fold‐changes in different tissues relative to liver were: for kidney, Gpx1 11X, Txnrd1 4X, Sepn1 3X, Sepw1 3X; for heart, Sepw1 6X, Sepn1 4X, Dio2 4X; for gizzard, Sepn1 6X, Selm 3X, Sepw1 2X; for breast, Sepw1 6X; for thigh, Sepw1 4X, Dio2 3X, Sepn1 2X. 3ˈ‐RACE was used to clone and sequence 17 selenoproteins, including 5 selenoproteins (Gpx3, Sepp1, Sepp2, Sepw1, Sep15) currently not predicted by the 2010 next‐generation sequencing of the turkey genome (PloS Biology 8:e1000475 (2010)). These sequences will be used to develop molecular biomarkers to characterize Se regulation in the turkey. (UW Hatch WI04909 and Selenium Nutrition Research Fund)
The GTPase ARFRP1 controls assembly of apoA1 to and lipidation of chylomicron in the Golgi of intestinal enterocyte
Authors: Jaschke Alexander , Chung Bomee , Hesse Deike , Kluge Reinhart , Heeren Joerg , Joost Hans-Georg , Schürmann Annette
Published: June 2021

Intestinal lipid metabolism is comprised of multi‐steps of vesicle trafficking. ADP‐ribosylation factor‐related protein 1 (ARFRP1) regulates protein trafficking between intracellular organelles. To study the role of ARFRP1 in intestinal lipid metabolism, Arfrp1 was deleted in mouse intestine (Arfrp1vil−/−), or depleted by siRNA transfection in Caco‐2 cells. Lipid absorption and lipoprotein production were examined. Decreased lipid absorption was detected in oral fat tolerance test in Arfrp1vil−/− mice. However, the apolipoprotein (Apo) B48 and ApoA4 in the plasma were higher, whereas the level of ApoA1 was markedly lower. Fractionation of the plasma showed that the chylomicron fractions of Arfrp1vil−/− mice contain lower triglyceride level, indicating that the Arfrp1vil−/− enterocytes produce a large number of chylomicron particles that are smaller in size containing less fat. Caco‐2 cells demonstrated that the defect in Arfrp1 expression caused decreased lipid release, but normal lipid uptake. In conclusion, ARFRP1 plays important roles in chylomicron lipidation in the Golgi and the secretion of ApoA1 in the intestine.

Grant Funding Source : Deutsche Forschungsgemeinschaft (Schu 750/5‐2; Schu 750/5‐3; GRK 1459; SFB958), Alexander von Humboldt Foundation
Although Equally Obese, High Fat Diet (HF)‐Fed Ovariectomized (O) Mice Respond with Greater Adipose Tissue (AT) Inflammation Than Sham‐Operated (S) Mice
Authors: Potter Victoria Jeanne Vieira , Strissel Katherine , Obin Martin S , Greenberg Andrew S
Published: June 2021

How O and S mice differ in response to HF in regards to AT inflammation, insulin resistance (IR), and hepatic steatosis (HS) was investigated. O and S mice (11 wk, n=16) were fed normal chow diet (NC) for 12 wks and then either switched to HF or continued on NC for 14 wks. Mice were compared for total (MRI) and regional (fat pad weight) body fat, IR (HOMA), HS (mgTG), AT immune cell content (FACS) and AT gene expression (qPCR). Data were analyzed using t‐tests and presented as mean±SEM.

O started heavier (33.5±0.8 vs. 27.4±0.8 g, p<0.05) with more body fat (34.6±1.5% vs. 17.6±1.9%, p<0.05) but S gained more rapidly on HF resulting in equally obese mice (48.6±1.0 g, 50.5% fat and 48.4±1.2 g, 47.7% fat for S and O on HF, p=0.24 (g), p=0.12 (% fat)). While neither NC group had HS (between groups, p=0.67), HS scores increased with HF (p<0.05 compared to NC) 2.8‐fold for S (136.3±26.4) and 2.6‐fold for O (127.5±22.5 mgTG/g) (between groups, p=0.81). On NC, O had higher HOMA‐IR (17.4±2.8 vs. 5.2±1.6, p<0.05) whereas both HF groups were IR (34.3±7.8 vs. 23.5±2.3 for O and S, p=0.23). HF increased AT T‐cells with O tending to have more than S (616±237 vs. 205±28 CD3+/10K events, p=0.097). O also had greater AT inflammatory gene expression (+2.1‐fold F480, +2.6‐fold CD11c, +7.3‐fold MCP1, +3.8‐fold IL12p40 compared to S, p<0.05).

Postmenopausal women may be more sensitive to HF‐induced metabolic disturbances, an effect that is uncoupled from obesity.

Grant Funding Source: NIDDK
Dietary vitamin D3 restriction differentially alters quadriceps contractile proteins in both sexes in the transgenic G93A mouse model of amyotrophic lateral sclerosis: a pilot study
Authors: Milionis Angelica , Parkhomenko Egor , Solomon Jesse Adam , Gianforcaro Alexandro , Hamadeh Mazen Jamal
Published: June 2021

Background

We previously demonstrated that dietary vitamin D3 (D3) restriction hastened the decline in functional outcomes following disease onset in the G93A mouse model of amyotrophic lateral sclerosis (ALS). ALS is a fatal neuromuscular disease characterized by motor neuron death, muscle weakness and progressive paralysis.

Objective

In this pilot study, we investigated the effects of dietary D3 at 2.5% the adequate intake (AI) in G93A mice on quadriceps contractile proteins (α‐actin; troponin C, trop C), inflammation (IL‐6), cell stress response (Hsp70), mitochondrial efficiency (UCP3) and apoptosis (CASP3 cleaved/pro ratio), mechanisms contributing to ALS pathology.

Methods

Starting at age 25 d, 42 G93A mice were provided food ad libitum with either adequate (AI; 1 IU D3/g feed; 12 M, 11 F) or deficient (DEF; 0.025 IU D3/g feed; 10 M, 9 F) D3. Differences in quadriceps protein content were considered significant at P ≤ 0.10.

Results

In males, DEF had 34% lower α‐actin (P = 0.096) and 38% higher trop C (P = 0.031) vs AI. In females, DEF had 32% lower trop C vs AI (P = 0.020). DEF males had 16% higher UCP3 (P = 0.093) and 57% higher trop C vs DEF females (P = 0.021).

Conclusion

Dietary D3 restriction differentially alters markers of muscle contractile proteins in both sexes in G39A mice, which may explain the associated decline in functional capacity. (Supported by NSERC and Faculty of Health‐York U).

Grant Funding Source : Supported by NSERC and Faculty of Health‐York U