bluuebunny/crossref_metadata_2025 huggingface dataset:
APOL1‐like gene insertion associated with increased blood pressure in the African Green Monkey
Authors: Rhoads Megan K. , Weaver Chelsea C. , Osborn Jeffrey L.
Published: June 2021

End stage renal disease affects 660,000 adults in the United States and disproportionally affects people of African descent. Studies have identified two alleles in the apolipoprotein L1 (APOL1) gene that are expressed in high frequency in African‐ American populations and may contribute to a 4–5 fold increased incidence of end stage renal disease (ESRD) in this demographic. The African Green Monkey (AGM, Chlorocebus aethiops sabaeus) is an Old World monkey species that develops spontaneous hypertension and is indigenous from the regions of Africa from which the two APOL1 alleles are known to exist in humans. We have recently reported that the AGM exhibits renal glomerular and vascular pathologies in conjunction with significant spontaneous hypertension. Furthermore, we report elsewhere that this spontaneous hypertension in the AGM is associated with significant proteinuria even when the animals are prehypertensive; suggesting that altered renal glomerular and/or tubular function in regulating protein excretion may precede the development of spontaneous hypertension in the AGM. This study hypothesized that gene sequence changes in the APOL1‐like gene region may be expressed in the AGM and are associated with increased blood pressure and altered renal function, similar to the human population. DNA was extracted from whole blood or frozen tissue in 44 adult males and the APOL1‐like gene region was sequenced. Bioinformatic analysis identified a 6 nucleotide insertion at base 329 that was positively associated with increased systolic blood pressures (p<0.05). Within the cohort, 2 animals were found to be homozygous for the sequenced insertion (mean ± SE SBP: 206.6±0.1 mmHg), 10 animals were heterozygous (SBP: 136.6±14.6 mmHg), and 32 animals did not have the insertion (SBP: 135.7± 7 mmHg). This data suggests that the insertion in the APOL1‐like gene may affect blood pressure regulation (and/or kidney function) in the AGM, providing a novel and exciting nonhuman primate model to study the progression of ESRD in a non‐human primate species that expresses variations within the APOL1 gene, which is known to correlate with early onset ESRD in African Americans. Ongoing studies are focused on increasing the AGM cohort size, adding normotensive and hypertensive females to the sequenced cohort, and collection of renal functional data on all sequenced animals to determine the effect of the APOL1‐like insertion on kidney function and blood pressure regulation in the AGM.

Support or Funding Information

Funding provided by Biomedical Science Research Group, LLC.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
EXERCISE TRAINING DOES NOT ALTER PROSTATE TUMOR CELL GROWTH IN RAT SERUM OR PROSTATE CONDITIONED MEDIA
Authors: Ardery Savannah , Horn Andrew , Opoku‐Acheampong Alexander , Baumfalk Dryden , Behnke Brad
Published: June 2021

Prostate cancer is the second leading cause of cancer‐related deaths in men in the United States with tumor aggressiveness (i.e., metastatic potential, ability to infiltrate surrounding tissue) being negatively related to patient prognosis and survivorship. Although there is promising data that exercise training may alter the tumor microenvironment to facilitate conventional treatment, the effects of exercise on prostate cancer growth is equivocal. Key facets of tumor aggressiveness include the ability of the tumor to spread (infiltrate) to surrounding tissue as well as for tumor cells to survive in the general circulation. Thus, we hypothesize that exercise training changes the tumor growth‐supporting environment of prostate tissue as well as blood serum to slow the migration of prostate cancer cells. The effects of exercise training on serum and prostate conditioned media (PCM) upon migration of prostate cancer cells in vitro was evaluated in this study. Blood serum was collected, and conditioned media was prepared from the prostates of sedentary (n = 10) and moderate‐intensity exercise‐trained (treadmill exercise for 5 days/week at 15 m/min, 15° incline for 60 min/day for 10–11 weeks; n = 10) male Copenhagen rats (~6 mo old). Cell migration of Dunning R‐3327 AT‐1 prostate cancer cells was determined via cell exclusion zone assay using serum, serum and fetal bovine serum (FBS), and prostate conditioned media from both rat groups for 24–96 hours. There was no significant difference in cell migration between serum alone, serum and FBS, or PCM from exercise‐trained rats compared to sedentary control, respectively, at any time point (e.g., PCM @96 hrs, Exercised Trained 514 ± 35 vs. Sedentary 508 ± 37 cells/field, p > 0.05). Although there is evidence suggesting exercise training can mitigate the pro tumor growth environment of adipose tissue, our data does not support an effect of exercise training on the tumor growth‐supporting environment of the prostate from in vitro measures. Future studies, using a more physiological oxygen range for in vitro tumor cell growth and/or conducted in vivo, are needed to corroborate or refute these initial results.

Support or Funding Information

American Cancer Society RSG‐14‐150‐1‐CCE (BJB)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Muscle protein synthesis during the early period of resistance training in rat
Authors: Kotani Takaya , Takegaki Junya , Noda Masahumi , Takagi Ryo , Nakazato Koichi , Ishii Naokata
Published: June 2021

Increase in muscle protein synthesis (MPS) by resistance exercise (RE) has been thought to be caused by increases in translational efficiency (major regulator: mammalian target of rapamycin (mTOR) signaling pathway) and translational capacity (ribosome content).

It has been shown that repeated bouts of RE leads to the attenuation of the activation of mTOR signaling and the increase in ribosome content after a bout of RE (Ogasawara et al. 2013). However, it is unknown whether MPS response to RE is also declined when exercise bout is repeated.

Purpose

To see if the acclimatization occurs in the response of protein metabolism to exercise during the course of RE , the present study investigated the changes in MPS, mTOR signaling pathway and ribosome content with the increase of RE bout.

Method

Male Sprague‐Dawley rats were randomly assigned into three groups: Sedentary (SED), resistance‐trained with 1 bout (1B), 3 bouts (3B). RE protocol consisted of 50 repetitions of maximal isometric contraction of the gastrocnemius muscle elicited by direct electric stimulation under anesthesia. A day recovery period was taken between each bout. Muscle samples were collected 6h after the last RE session.

Results

Amount of puromycin‐labeled peptides was larger in trained groups than in SED, but no significant difference was seen between 1B and 3B. Posphorylation of p70S6K was larger in trained groups than in SED, and significantly larger in 1B than in 3B. By contrast, ribosomal RNA content was larger in trained groups than in SED, and significantly larger in 3B than in 1B.

Conclusion

MPS after repeated bouts of RE was unchanged from that after a single bout in spite of the attenuated response of mTOR signaling. This may be caused by the compensatory increase in ribosome content with the increase in the exercise bout.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Defining Acceptable Cold‐Water Immersion Times for the Treatment of Exertional Hyperthermia When Rectal Temperature Measurements are not Available
Authors: Poirier Martin P. , Notley Sean R. , Gagnon Daniel , McGinn Ryan R. , Friesen Brian J. , Flouris Andreas D. , Kenny Glen P.
Published: June 2021

Exertional hyperthermia is most effectively treated with immediate whole‐body cold‐water immersion to rapidly cool the body to the safe rectal temperature (Tre) of 38.6°C, which is the cooling limit recommended to negate any risk associated with overcooling hyperthermic individuals. However, the safe use of cold‐water immersion is reliant on real‐time measurement of Tre to identify the appropriate immersion time, which is often unavailable in emergency situations. The purpose of this study was to determine appropriate immersion times for the immediate treatment of exertional hyperthermia for a range of water temperatures (2°C to 26°C) and following a treatment delay (20 min and 40 min) to guide emergency management in the absence of continuous Tre measurements. Data were extracted from seven published studies (143 experimental sessions) involving 79 participants (65 males, 14 females; age: 26 ± 6 years; height: 177 ± 9 cm; weight, 76.9 ± 13.0 kg; body fat: 17.3 ± 6.9%; peak oxygen consumption: 56.9 ± 7.9 mL/kg/min). In each study, individuals rendered hyperthermic (Tre 39.5–40.0°C) during exercise in the heat were treated immediately with immersion in water at 2°C, 8°C, 14°C, or 26°C. Separate study conditions assessed cold‐water immersion (2°C) following a 20 and 40 min treatment delay. From these data, receiver operating characteristics curves were used to define acceptable cooling times (time for Tre to reach 38.6°C) for each condition (all p<0.05). Our analysis revealed that 9 min would be the recommended cooling time for immersion in water temperatures ranging from 2°C to 8°C (average sensitivity at 2°C: 0.84, average sensitivity at 8°C: 0.82; average specificity at 2°C: 0.82, average specificity at 8°C: 0.96). For immersion in water temperatures between 14°C and 20°C, the suggested cooling time was 10 min (average sensitivity: 0.80; average specificity: 0.76), whereas it was 14 min at 26°C (average sensitivity: 0.73; average specificity: 0.79). When the gold standard water temperature of 2°C is available, a cooling time of 11 min is recommended if immersion is delayed between 20 and 40 min (average sensitivity: 0.84; average specificity: 0.94). Our results provide the first clinical guidance to health practitioners for the emergency treatment of exertional hyperthermia using water immersion at a range of water temperatures and following a treatment delay when Tre measurements are unavailable.

Support or Funding Information

Natural Sciences and Engineering Research Council of Canada (grant held by Dr. Glen P. Kenny).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Growing Evidence that Periderm is Essential for Orofacial and Epidermal Development
Authors: Schutte Brian C.
Published: June 2021

Orofacial clefting is one of the most common birth defects, affecting about 1/700 births world wide. The cause of orofacial clefting is complex, including multiple genetic and environmental factors. To date, genome wide association studies have identified 36 loci that contribute risk, and linkage studies have identified the gene involved in 249 rare syndromes. However, these loci still only account for a fraction of the overall heritability of orofacial clefting. To determine the “missing heritability”, we need a better understanding of the pathological mechanisms that lead to orofacial clefts. Recent human and animal genetic studies suggest that proper periderm development is one essential pathway during palatogenesis. The periderm is the superficial layer of squamous epithelial cells that covers the ectoderm of mammalian embryos. During palatogenesis, the periderm covering the medial edge of the palatal shelves must degenerate at a precise moment to allow palatal fusion. If the periderm degenerates too early, or too late, the palatal shelves may not fuse, leading to a cleft palate. Based on mutant mouse studies, 20 genes have been identified as essential for proper periderm development. Significantly, DNA variation in 13 of the 20 genes causes and/or contributes risk for orofacial clefting in humans, including transcription factors (IRF6, GRHL3, TP63, TBX1, TFAP2A) and cell signaling molecules (FGF10, FGFR2, NOG, RIPK4, TGFB3). Several of these genes were also shown to be required for development of the enveloping layer during zebrafish embryogenesis. Like the mammalian periderm, the enveloping layer is the superficial layer of epithelium that surrounds the zebrafish embryo. The apparently conserved functions of these genes in periderm and enveloping layer has allowed the development of robust functional assays in zebrafish for testing potentially pathogenic mutations found in patient with orofacial cleft. Moreover, the significance of this set of genes is not limited to development, as somatic mutations and altered expression has been associated with cancer, especially squamous cell carcinoma.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
LMCD1 acts as a coactivator for E2F1 in CDC6 expression to promote human aortic smooth muscle cell replication and atherogenesis
Authors: Singh Nikhlesh K. , Janjanam Jagadeesh , Zhang Baolin , Mani Arul M. , Traylor James G. , Orr A. Wayne , Rao Gadiparthi N.
Published: June 2021

In exploring the mechanisms underlying restenosis, we have identified LMCD1 as a highly responsive gene to thrombin in human aortic smooth muscle cells (HASMCs). Depletion of LMCD1 levels inhibited human but not murine vascular smooth muscle cell replication. LMCD1 via interacting with E2F1 mediates thrombin‐induced CDC6 expression in the regulation of HASMC replication. Thrombin‐induced LMCD1 and CDC6 expression exhibited a requirement for PAR1‐mediated Gαq/11‐dependent PLCβ3 activation. In addition, the expression of LMCD1 was highly induced in SMC of human atherosclerotic lesions and correlated with CDC6 expression and replication marker Ki67. Furthermore, the LMCD1 and SMCαactin‐positive cells were found to possess higher cholesterol levels in the atherosclerotic lesions. Thus, these findings for the first time show that LMCD1 via acting as a coactivator for E2F1 in CDC6 expression modulates HASMC replication and hence promotes human atherogenesis.

Support or Funding Information

This work was supported by grants HL069908 and HL103575 (to GNR) and HL098435 and HL133497 (to AWO) from NHLBI of NIH.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Evidence for Activation of Host Cell Protein Kinase C Signaling from Proteomics Analysis of Coxiella burnetii‐Infected THP‐1 Cells
Authors: Funk Cornelius Joel , Jackson Christa
Published: June 2021

The bacterium Coxiella burnetii can infect cells found in the human lung and cause a respiratory tract infection that manifests as Q‐fever disease. The acute infection typically results in mild flu‐like symptoms that are treatable with antibiotics; however, chronic infections can lead to endocarditis, hepatitis, or death, if left untreated. Bacteria enter alveolar macrophages within a phagosome, but rather than being destroyed by the hydrolytic lysosomal enzymes, C. burnetii induces the host cell to develop a lysosome‐like organelle designated the parasitophorous vacuole (PV) where replication takes place. The PV grows in size to accommodate the increasing number of replicating cells before the bacterial cells are released as the host cell is destroyed. The objective of this study was to identify Protein Kinase C (PKC) substrates and other activated cell signaling pathways using proteomics. Proteins from infected and uninfected THP‐1 cell samples were labeled using isobaric tagging and analyzed using an ion trap mass analyzer (LC‐MS/MS) to identify proteins and post‐translational modifications that were altered during infection. Previous work indicated that C. burnetii infections lead to activation of several Protein Kinase C (PKC) isoforms, which in turn lead to phosphorylation of the PKC substrate MARCKS. Analysis of infected THP‐1 cell samples identified two additional PKC substrates that were phosphorylated during the infection, MARCKSL1 (a MARCKS‐related protein) and ABCA1 (a cholesterol efflux protein). Additional analysis indicated that both proteins were upregulated during the infection at the gene and protein level using qPCR and immunoblotting, respectively. These results provide additional evidence that PKC cell signaling is altered during C. burnetii infection of the host cell and may provide insight into critical events that can be targeted for inhibition of the infection.

Support or Funding Information

Supported by a grant from Arkansas INBRE (NIH NIGMS P20 GM103429).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Human Macrophage Derived Myeloperoxidase Exacerbates Nonalcoholic Steatohepatitis Disease (NASH) in Diet‐induced Obesity
Authors: Katunga Lalage A. , Franke Jacob D. , Schulte Kevin A. , Ford David A.
Published: June 2021

Background

Hepatic infiltration of polymorphonuclear leukocytes (PMNs) is a key driver of pathogenesis in non‐alcoholic steatohepatitis (NASH). Lipotoxicity arising from elevated free fatty acids in NASH is postulated to advance PMN activation and recruitment. Myeloperoxidase (MPO), a PMN‐derived enzyme mechanistically linked to oxidative stress (ROS) in inflammation, may contribute to this feedback. Chlorinated fatty acids (2‐ClFAs) are an MPO by‐product produced when HOCl targets plasmalogen phospholipids. 2‐CIFAs induce PMN activation, adhesion and ROS mediated cellular damage. In human patients, a strong positive correlation between MPO expressing cells and severity of NASH has been observed. However, mouse macrophages lack MPO and this is a critical limitation of current models. As a result, the contribution of MPO to NASH remains poorly understood.

Methods

To investigate the role of MPO in NASH, C57Bl/6J mice expressing macrophage transgenic human MPO (hMPOTg) were fed a 40% high fat (HF) diet for 10 weeks. At the end of the study biomarkers of hepatocellular damage and PMN infiltration were measured. Alterations in lipid species were detected using electrospray ionization tandem mass spectrometry (ESI‐MS/MS) lipidomics in order to elucidate contributing lipids to NASH.

Results

Here we show hMPOTg is associated with significant alteration in the hepatic lipidome, increased infiltration of PMNs, levels of MPO lipid by‐products and exacerbated hepatic steatosis. HF fed hMPOTg mice showed greater weight gain and hepatomegaly. Increased infiltration of PMN in hMPOTg HF livers was supported by immunohistochemistry and PCR analysis of PMN biomarkers. Significantly higher triglyceride levels were detected in hMPOTg HF fed plasma and livers. Major hepatic lipid species of cholesterol esters, phosphatidylcholine, and phosphatidylserine were also significantly altered. Systemic pro‐inflammatory 2‐CIFA levels were increased in HF fed hMPOTg.

Conclusion

Together, our results highlight the significant contribution of hMPO to hepatic lipid homeostasis. MPO is currently exploited as a biomarker and therapeutic target in cardiovascular disease. Expanding our understanding of MPO may extend the benefits of similar therapeutic strategies to patients suffering from NASH and metabolic syndrome.
Sympathetic nerve response to optogenetic inhibition of PVN‐RVLM neurons in anesthetized rats with heart failure
Authors: Hanai Eri , Kumada Nao , Watanabe Tatsuo , Koba Satoshi
Published: June 2021

Central neuronal cell groups that underlie enhanced sympathetic nerve activity (SNA) in heart failure (HF) have not been identified. Here, we tested the hypothesis that paraventricular hypothalamic nucleus (PVN) neurons that send axonal projections to the rostral ventrolateral medulla (RVLM) mediate this abnormality by examining the effect of optogenetic inhibition of PVN‐RVLM neuron activity on renal SNA (RSNA) in anesthetized rats after myocardial infarction (MI). More than one week after left coronary artery ligation to induce MI, rats received bilateral microinjection into the PVN of an adeno‐associated virus (AAV) vector that encodes reporter protein mcherry (control‐MI rats, N=6) or the light‐activated inhibitory opsin Archaerhodopsin‐eYFP (ArchT‐MI rats, N=12). The AAV vector encoding ArchT‐eYFP was also bilaterally microinjected into the PVN of the sham‐operated rats (ArchT‐sham rats, N=6). More than three weeks later, intermittent bouts (1‐ to 4‐sec stimulation to non‐stimulation) of photostimulation (532 nm wavelength, 5 mW) for 1 min were bilaterally provided to the RVLM of rats anesthetized with a mixture of urethane and α‐chloralose. The RSNA responses to 12 optogenetic stimulations were superimposed on one another and averaged. The superimposing analysis showed that 1‐sec photostimulation significantly (P<0.05) changed RSNA from baseline in ArchT‐MI rats while this stimulation had no effect in control‐MI or ArchT‐sham rats. During the early 500‐msec period of 1‐sec photostimulation, the RSNA changes from baseline were not significant or did not differ among rat groups (+7 ± 6, +4 ± 15, and +14 ± 10% for ArchT‐MI, control‐MI, and ArchT‐sham rats, respectively). During the late 500‐msec period, on the other hand, a significant RSNA inhibition from baseline was detected in ArchT‐MI rats (−35 ± 10%), which was significantly different from the RSNA changes in control‐MI and ArchT‐sham rats (+6 ± 9 and +15 ± 11%). Left ventricular end‐diastolic pressure was increased in rats after MI [+7 ± 3 mmHg, 40 ± 5% of infarct size (IS)] as compared to sham‐operated rats (+2 ± 0 mmHg, 0 ± 0% of IS), indicating heart dysfunction in rats after MI. Taken together, we suggest that dysfunction of PVN‐RVLM neurons underlies enhanced SNA in HF.

Support or Funding Information

Supported by JSPS KAKENHI 15H05367 (SK) & 16K15190 (SK), the Nakatomi Foundation grant (SK), and the Takeda Science Foundation grant (SK).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Salt Diet Influences Endothelin‐1 Signaling in Renal Sensory Nerves
Authors: Becker Bryan K. , Speed Joshua S. , Pollock David M.
Published: June 2021

Renal denervation is an effective anti‐hypertensive treatment in both humans and many animal models. However, it is unclear if the benefits of renal denervation are due to severing of the efferent (motor) nerves, afferent (sensory) nerves, or both. Recently, we reported that total renal denervation lowered blood pressure and global sympathetic tone in a model of endothelin B receptor (ETB‐R) deficiency without affecting renal excretory function or sodium balance suggesting a role for the afferent nerves in mediating hypertension and sympathetic tone in this model. High salt diet and endothelin‐1 signaling sensitize afferent activity, but the long‐term consequences and mechanisms of afferent sensitization are still relatively unknown. Thus we hypothesized that changes in salt diet would alter the gene expression profiles in renal afferent nerves following a high or low salt diet or endothelin receptor antagonist treatment. We isolated dorsal root ganglia (DRG) that contain the cell bodies of renal afferent nerves from Sprague‐Dawley rats fed either normal salt (NS, 0.49% NaCl), low salt (LS, 0.04% NaCl), or high salt (HS, 4.0% NaCl) for three weeks, or normal salt with 10 mg/kg/d ABT‐627 (ETA‐R antagonist) or 30 mg/kg/d A‐192621 (ETB‐R antagonist) for one week for qRT‐PCR analysis. Rats fed HS diet had significantly elevated expression of brain‐derived neurotrophic factor compared to NS (5.9 ± 1.8 relative to NS; p=0.04, n=3–4/group) indicating that HS diet activates renal afferent nerves as has been previously reported. Animals fed LS diet were not significantly different than NS. Neither salt diet had a significant effect on endothelin‐1 expression in DRG. Surprisingly, both LS and HS diets decreased the expression of both ETA‐R (0.7 ± 0.01 relative to NS p=0.1 and 0.4 ± 0.2 relative to NS p=0.04; respectively) and ETB‐R (0.5 ± 0.03 relative to NS p<0.001; and 0.5 ± 0.1 relative to NS p<0.001; respectively). Antagonism of ETA‐R resulted in a 2.0 ± 0.3 fold increase in endothelin‐1 expression in DRG compared to NS (p=0.02), while ETB‐R blockade had no effect (p=0.99) compared to NS, suggesting that ETA‐R activity may suppress endothelin‐1 expression in renal afferent nerves. These data suggest that salt diet influences activity of renal afferent nerves and that endothelin‐1 signaling in afferent nerves may be important modulators of activity.

Support or Funding Information

T32HL007457 to BKB; K99HL127178 to JSS; and P01HL136267 to DMP

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Relationship Between Heart Rate Variability (HRV) and Anxiety Through Music Intervention
Authors: Tolley Annalise Julia , Vick Robert Stephen
Published: June 2021

Background

Research shows that lower heart rate variability (HRV) is associated with multiple health risks, including early mortality, congestive heart failure and mental illness. Research on the relationship between HRV and anxiety has been inconclusive but should be studied, as HRV may be a noninvasive indicator of overall mental health. Music has been used as an inexpensive intervention method to significantly lower self‐reported anxiety in multiple populations.

Objective

To determine the strength of the possible relationship between anxiety and HRV with music intervention.

Subjects and Methods

A within‐subjects experimental design was used with undergraduate students (n=32). Self‐reported anxiety used STAI, followed by the collection of seven minutes of baseline EKG data. Seven minutes of pre‐selected, “relaxing” music was played (intervention) while physiological indices were again collected. The STAI was re‐administered.

Results

After music intervention, significant reduction in anxiety (p<0.001) and heart rate was demonstrated (p<0.01), with a significant increase in RR (p<0.01), SDRR (p<0.01), and pRR50 (p<0.01). No correlation was found between the change in anxiety and physiological indices (p=0.737).

Conclusions

Undergraduate students may benefit from music intervention, as music significantly improved self‐reported anxiety and physiological anxiety, as measured by STAI score and HRV, respectively. However, these improvements seemed to occur independently, thus decreasing the strength of the proposed relationship between HRV and anxiety in the literature. Elon University IRB #17‐083.

Support or Funding Information

Research supported by Elon University Undergraduate Research Program (URP) and Elon College Fellows (ECF) program.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Chronic Hypoxia Attenuates Endothelium‐dependent Hyperpolarization‐induced Vascular Relaxation in Pulmonary Artery and Leads to Pulmonary Hypertension
Authors: Zhang Qian , Varghese Mathews Valuparampil , Si Rui , Tsuji‐Hosokawa Atsumi , Watanabe Makiko , Hosokawa Susumu , Wang Jian , Makino Ayako
Published: June 2021

Endothelial cell dysfunction is implicated in the development and progression of many cardiovascular diseases including pulmonary hypertension (PH). It has been well documented that endothelium‐dependent relaxation (EDR) is attenuated due to decreased NO bioavailability in pulmonary artery (PA) of PH model animals; however there is few report investigating the role of endothelium‐dependent hyperpolarization (EDH)‐mediated vascular relaxation in PH. In this study, we examined the role of chronic hypoxia on EDH‐induced pulmonary arterial relaxation with a special focus on connexin 40 (Cx40). Connexins are a group of membrane proteins that form gap junctions between the cells and serve as a tunnel during electrical propagation (e.g., hyperpolarization). Cx40 is predominantly expressed in vascular endothelial cells (ECs). We first examined vasorelaxant properties in the different size of PAs dissected from wild type (Wt) and Cx40 knockout (KO) mice. There was no difference of acetylcholine (ACh)‐induced relaxation (i.e., EDR) in second order of PAs between Wt mice and Cx40 KO mice, while EDR was significantly attenuated in the fourth order of PAs of Cx40 KO mice compared to the Wt mice. In the second order of PAs, we did not observe EDH‐dependent vascular relaxation in both Wt and Cx40 KO mice. In the fourth order of PAs, strong EDH‐dependent relaxation was observed in Wt mice and it was significantly reduced in Cx40 KO mice. Cx40 KO mice exhibited a significant increase in right ventricle systolic pressure (RVSP) compared to Wt mice. Chronic hypoxia (10% O2, 4 weeks) increased RVSP in both Wt and Cx40 KO mice and Cx40 KO mice exposed to hypoxia exhibited significantly higher RVSP than Wt mice exposed to hypoxia. Furthermore, chronic hypoxia attenuated EDR and EDH‐dependent relaxation in the fourth order of PAs from Wt mice; however, there was no difference of EDR and EDH‐dependent relaxation in the fourth order of PAs in Cx40 KO mice. Mouse pulmonary endothelial cells isolated from hypoxia‐exposed Wt mice exhibited significant decrease in Cx40 protein level compared to Wt mice exposed to normoxia. These data suggest that chronic hypoxia decreases Cx40 protein expression and attenuates EDH in small PAs that subsequently leads to increase in pulmonary arterial resistance and develops pulmonary hypertension.

Support or Funding Information

NIH R01HL115578

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Increased Glycolysis Contributes to Pulmonary Vascular Remodeling via ERK‐dependent Calpain Activation in Pulmonary Arterial Hypertension
Authors: Kovacs Laszlo , Cao Yapeng , Han Weihong , Meadows Louise , Kovacs‐Kasa Anita , Verin Alexander , Barman Scott , Huo Yuqing , Su Yunchao
Published: June 2021

Pulmonary arterial hypertension (PAH) is a life‐threatening lung disease which is characterized by pulmonary vascular remodeling due to the abnormal proliferation of vascular smooth muscle cell (SMCs) and overproduction of extracellular matrix (ECM) proteins including collagen. It has been shown that a number of growth factors such as platelet‐derived growth factor (PDGF) as well as the metabolic shift in energy production from oxidative phosphorylation to glycolysis participate in PAH in animal models and patients. We recently reported that calpain mediates collagen synthesis and proliferation of pulmonary arterial SMCs (PASMCs) contributing to the pathogenesis of PAH. The aim of this study is to investigate the mechanisms by which glycolytic shift induces calpain activation in PAH. PASMCs were incubated with PDGF‐BB (10 ng/ml) for 24 h, after which protein content of 6‐Phosphofructo‐2‐kinase/fructose‐2, 6‐bisphosphatase 3 (PFKFB3) and lactate concentration in the cell lysates and in the culture medium were measured. We found that PDGF‐BB significantly increases the protein levels of PFKFB3 and the lactate production. Our results also showed that inhibition of PFKFB3 attenuates PDGF‐induced calpain activity, collagen synthesis and proliferation of PASMCs. Treatment of PASMCs with lactate markedly increased the activities of calpain and extracellular signal–regulated kinase (ERK) without affecting the protein levels of calpain‐1, calpain‐2 and calpastatin in PASMCs suggesting that it may regulate the calpain activity via posttranslational mechanism. Moreover, inhibition of calpain‐2, but not calpain‐1, attenuates the lactate‐induced collagen synthesis and proliferation of PASMCs. In addition, pre‐treatment of the PASMCs with ERK 1/2 inhibitor PD98059 diminishes increases in calpain‐2 phosphorylation at serine 50, collagen synthesis and proliferation of PASMCs induced by lactate. More importantly, pharmacological inhibition of ERK 1/2 by PD98059 attenuates the progression of Sugen/Hypoxia‐induced pulmonary hypertension and pulmonary vascular remodeling in rats. In summary, we have demonstrated that ERK‐stimulated calpain signaling is a critical pathway in PAH which mediates cell proliferation and collagen synthesis in pulmonary vascular smooth muscle cells via enhanced glycolysis.

Support or Funding Information

Supported by NIH (YS), Department of Veterans Affairs (YS), FAMRI (YS) and AHA (LK).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Role of G protein‐coupled estrogen receptors in pulmonary hypertension
Authors: Wolfel Logan C. , Detweiler Neil D. , Cross Laura Weise , Hathaway Helen J. , Jernigan Nikki L. , Prossnitz Eric R. , Resta Thomas C. , Snow Jessica B.
Published: June 2021

Chronic hypoxia (CH) resulting from chronic obstructive pulmonary disease, sleep apnea, and high altitude exposure leads to oxidative stress and increased pulmonary vascular resistance. The resultant pulmonary hypertension (PH) contributes to right ventricular hypertrophy and may culminate in right heart failure, peripheral edema, and dyspnea. Because the G protein‐coupled estrogen receptor (GPER) has been implicated in oxidative stress in systemic hypertension, we hypothesized that GPER contributes to the development of CH‐induced PH. To test this hypothesis, we assessed indices of PH in female wild type (WT) and GPER knockout (KO) mice exposed to normoxia or CH (4 wk, PB= 0.5 atm) (n= 4–6/group). Right ventricular systolic pressure (RVSP) was measured by direct cardiac puncture during isoflurane anesthesia. In addition, right ventricular hypertrophy and polycythemic responses to CH were determined from Fulton's index (right ventricle/(left ventricle + septum weight)) and hematocrit, respectively. CH resulted in greater RVSP in WT mice (p<0.05), indicative of PH. Although CH also tended to increase Fulton's index and hematocrit in WT mice, these responses did not reach statistical significance. GPER KO mice unexpectedly showed significantly (p < 0.05) elevated RVSP, right ventricular hypertrophy and hematocrit compared to WT controls under normoxic conditions. Furthermore, these responses to GPER knockdown were not potentiated by CH. We conclude that GPER deficiency results in PH under normoxic conditions, supporting a role for GPER in the maintenance of the pulmonary circulation as a low‐pressure circuit.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ryanodine Receptor 1 mRNA Expression is Increased by Post‐Natal Maturation and Long Term Hypoxia in Sheep Pulmonary Arteries
Authors: Murray Samuel , Dasgupta Chiranjib , Zhang Lubo , Wilson Sean M.
Published: June 2021

Ryanodine receptors (RyRs) are well regarded for being important to vasorelaxation that occurs during the birth transition and with hypoxic pulmonary vasoconstrictor responses. Previous studies from our group show that RyR mediated Ca2+ spark events are suppressed in fetal pulmonary arterial myocytes and that these events are significantly modified by exposure to long term high altitude hypoxia. To begin to resolve the molecular underpinnings of these physiological responses we performed quantitative real time PCR for mRNA expression of the RyR1 isoform, which is one of three relevant isoforms that are likely to be expressed in pulmonary arterial myocytes. Pulmonary arterial (PA) segments were isolated from near‐term fetal or adult sheep housed at low altitude (300m) or exposed to high altitude (3,801m) for over 100 days. Comparisons of RyR1 mRNA expression were then made to the housekeeping gene beta‐actin. Based on these preliminary studies we found that the ΔCt for RyR1 mRNA expression relative to beta actin was significantly lower in the fetus relative to the adult independent of altitude. The ΔΔCt corresponded to a 12–17 fold increase in RyR1 mRNA expression due to maturation, which potentially accounts for previously shown maturational related enhancements in Ca2+ spark activity. Altitude caused a 2.8 fold increase in RyR1 mRNA expression in adult PA that correlate with previously shown maturational induced increases in spark activity. Interestingly, a 3.8 fold increase in RyR1 mRNA expression observed in fetal PA following hypoxia did not correspond to the hypoxia‐related depression in Ca2+ spark activity that we previously reported. Overall, these preliminary studies show pronounced changes in RyR1 mRNA expression that are likely to be important drivers of pulmonary vascular development as well as underlie pathologies due to long term high altitude exposure.

Support or Funding Information

This work is supported by The National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development grant number HD083132 and HD069746.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Differential Respiratory Response of Isolated Cardiac Mitochondria from Young and Aged Mice towards Nitric Oxide Synthase Inhibitors
Authors: Sakamuri Siva SVP. , Sure Venkata NLR. , Sperling Jared A. , Mahalingam Padmini S. , Dholakia Monica H. , Evans Wesley R. , Katakam Prasad VG.
Published: June 2021

Mitochondrial respiratory dysfunction is proposed to be an important underlying mechanism in the aging‐induced cardiac abnormalities. Identifying the mechanisms involved in the development of aging‐induced respiratory dysfunction in cardiac mitochondria could be useful to develop therapeutic strategies to reduce the risk of developing cardiovascular diseases. Role of mitochondrial nitric oxide synthase (NOS) to aging‐induced respiratory changes in cardiac mitochondria are not studied previously. Here we treated the isolated cardiac mitochondria from young (3 months) and old mice (18 months) hearts with neuronal NOS inhibitor (nNOS, ARL 17477 dihydrochloride or ARL) and endothelial NOS inhibitor (eNOS, N5‐(1‐Iminoethyl)‐L‐ornithine or NIO) and studied the respiratory characteristics using Seahorse Xfe24 analyzer.

Results

Mitochondria from the old mice hearts exhibited significantly increased basal respiration (24.7%, 169.0±14.0 vs 135.5±5.1, p≤0.05) with unchanged ATP production. They also showed a significant decrease in state IIIu respiration (23%, 635.4±40.2 vs 826.4±49.2, p≤0.05) and also the membrane potential. Both ARL and NIO treatments significantly decreased state IIIu respiration (22.1%, 643.7±34.4 vs 826.4±49.2, p≤0.05 & 23.9%, 448±18.5 vs 587.1±34.8, p≤0.05 respectively) in mitochondria from young mice hearts without affecting membrane potential and oxidative stress parameters. Interestingly, ARL and NIO neither induced similar responses in the mitochondria from the old mice hearts nor they corrected the aging‐induced decline in state IIIu respiration and membrane potential. Mitochondria from the old mice hearts have increased nNOS protein levels (421%, 1.98±0.80 vs 0.38±0.20, p≤0.05) with decreased protein S‐nitrosylation (46.25%, 8.3±1.5 vs 15.44±3.2, p≤0.07). The observed differential respiratory responses of cardiac mitochondria from young and old mice following nNOS and eNOS inhibitors were associated with reduced protein S‐nitrosylation in mitochondria from young mice hearts (64.2%, 5.53±0.35 vs 15.44±3.2, p≤0.05 & 65.7%, 5.3±0.84 vs 15.44±3.2, p≤0.05 respectively) with unaltered nitrosylation in mitochondria from old mice hearts.

Conclusions

Thus the functional loss of mitochondrial nNOS and eNOS in the aged hearts accompanied by the reduced NO‐mediated regulation of mitochondrial proteins contributes to the aging‐induced mitochondrial dysfunction.

Support or Funding Information

American Heart Association (PVG: 14SDG20490359 and VNS: 16PRE31450006) and National Institute of Health: National Institute of Neurological Disorders and Stroke and National Institute of General Medical Sciences (PVK: R01NS094834).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Contraction and Relaxation Coupling Unaffected by Disease in Canine and Human Myocardium
Authors: Santini Jorge , Repas Steven J. , Canan Benjamin D. , Billman George E. , Kilic Ahmet , Whitson Bryan , Janssen Paul M.L
Published: June 2021

In healthy rodent isolated ventricular myocardium, a strong positive correlation (R2>0.95) has been observed between the rate of contraction versus rate of relaxation. Additionally, this correlation remains when muscles are stimulated to contract at different length, different frequency and various levels of beta‐adrenergic stimulation. However, there are drastic differences in EC coupling in small rodents versus larger mammals, including humans. Human and other large mammals, such as dogs, have a much wider range (~10 fold) of modulation of cardiac force and kinetics, thus it is unclear if a contraction‐relaxation coupling exists in larger mammals. In addition, it is unknown if such a relationship would be effected by disease. In this study, we investigated whether there is a correlation between maximal speed of contraction (dF/dt) and relaxation (‐dF/dt) in normal and exercise trained canines, with or without a myocardial infarction, as well as in normal human non‐failing, failing ischemic and failing non‐ischemic myocardium. Preliminary analysis on n=42 canines and N=54 humans suggests that there is a tight coupling between the maximal speed of contraction and relaxation in normal canine (R2=0.99) and non‐failing human myocardium (R2=0.99), with nearly identical slopes of this correlation. Additionally, within exercise or diseased hearts, there is no significant change with this correlation or slope of contraction‐relaxation coupling. We conclude that contraction‐relaxation coupling is a fundamental property that is unaffected by physiological contractile regulatory mechanisms.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Exosomal MicroRNA‐27a Passenger Strand Was Upregulated in Chronic Heart Failure
Authors: Tian Changhai , Gao Lie , Zucker Irving H.
Published: June 2021

Under cardiac stress, the heart undergoes extensive cardiac remodeling that results in cardiac fibrosis and hypertrophy, which contribute to chronic heart failure (CHF). Data from our lab revealed that microRNA‐27a contributes to the Nrf2 translational inhibition in cardiomyocytes through the communication with cardiac fibroblast‐derived exosomes. Interestingly, microRNA‐27a passenger strand (also call microRNA‐27a*) in infarcted cardiac tissues and extracellular exosomes shows a relatively high abundance which normally undergoes intracellular degradation (Figure. 1). However, the role of microRNA‐27a* in the onset and progression of CHF remains unclear. A bioinformatics analysis using TargetScan software revealed that PDZ and LIM domain 5 (PDLIM5) is one of potential targets of miroRNA‐27a*, and cardiomyocyte‐specific PDLIM5 knock‐out mice have been shown to develop cardiomyopathy, suggesting that PDLIM5 plays a major role in cardiac muscle structure and function, and may contribute to the progression of cardiomyocyte hypertrophy. Thus, we hypothesize that microRNA‐27a* may regulate PDLIM5 through exosomal communication with cardiomyocytes in chronic heart failure. Using western blotting analysis, we demonstrate down‐regulation of PDLIM5 in the infarcted heart compared to normal heart (Figure. 2), which correlated with the alterations of microRNA‐27a* in both of infarcted heart tissue and plasma. Additionally, our in vitro cell culture studies demonstrate that extracellular exosomes secreted by angiotensin II‐treated cardiac fibroblasts enriched abundant microRNA‐27a*, which promoted hypertrophic gene expression in cardiomyocytes. These findings suggest that exosomal microRNA‐27a* secreted by cardiac fibroblasts in response to cardiac stress, may act as a paracrine signaling mediator of cardiomyocyte remodeling that has potential as a therapeutic target and one of diagnostic markers.

Support or Funding Information

This work was supported by National Institutes of Health National Heart, Lung, and Blood Institute grant PO1 HL 62222 (IHZ)

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Association between cardio‐metabolic risk factors, plasma catecholamines and cognitive performance in Mexican pre‐adolescents
Authors: Soto‐Piña Alexandra Estela , Flores‐Reséndiz Constantino , Valdés‐Ramos Roxana , Benítez‐Arciniega Alejandra Donají , Martínez‐Carrillo Beatriz
Published: June 2021

Cardiovascular and metabolic syndrome (MS) risk factors are associated with the generation of vascular cognitive impairment and aging. Dislipidemia and obesity are two of the main factors that promote cognitive decline because of the accumulation of fat in vascular tissue and neuroendocrine disruption. In order to prevent the development of these alterations into chronic diseases, it is important to identify and correct them at earlier life stages. The hypothesis of this study was that metabolic risk factors and sympathoadrenal alterations in pre‐adolescents are associated with cognitive dysfunction. Our aim was to determine whether there is a correlation between cardio‐metabolic risk factors, plasma catecholamines as well as memory, attention and executive functions. We performed a cross‐sectional study where 139 pre‐adolescents 10–14 years old were involved. Memory, attention and executive functions were evaluated using Neuropsi test. Blood concentrations of Triacylglycerols (TG), cholesterol, low density lipoprotein‐cholesterol (LDL‐c), very low lipoprotein‐cholesterol (VLDL‐C), high density lipoprotein cholesterol (HDL‐C) and plasma catecholamines were measured as well. Pearson correlation and multivariate regression analyses were performed to find a relation between these variables. We found that TG and VLDL‐C were negatively related to memory (−0.19 and −0.19, respectively; *p<0.05,). Multivariate regression analysis for memory and executive functions showed that each one has a negative relation with HDL‐c (B= −1.12 and −0.8, respectively; *p<0.05). Moreover, plasma epinephrine was inversely related to executive functions (B=−0–05; *p<0.05). Therefore, elevations of LDL‐c, TG and epinephrine as well as low HDL‐c blood concentrations can alter cognitive performance during pre‐adolescence.

Support or Funding Information

This investigation was supported by grants 3838/2014FSH and 3561/2015PIC from Universidad Autónoma del Estado de México.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.