bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Renal Denervation and Celiac Ganglionectomy on Mean Arterial Pressure in the Hypertensive Schlager (BPH/2J) Mice
Authors: Gauthier Madeline M , Breitenstein Claire , Asirvatham‐Jeyaraj Ninitha , Osborn John W 
Published: November 2023

Renal denervation (RDNx) lowers mean arterial pressure (MAP) in a number of models of hypertension. Less well studied is the effect of celiac ganglionectomy (CGx), a procedure that has proven equally effective at lowering MAP in some animal models. The mechanism of action of both surgical interventions remains unknown, however evidence suggests RDNx may affect the presence of inflammatory markers in the kidneys. In this study, we hypothesized that RDNx and CGx would both lower MAP in genetically hypertensive Schlager (BPH/2J) mice and that this would correlate with a decrease in sympathetic activity and a decrease in proinflammatory cytokines. BPH/2J mice underwent radiotelemeter implantation for monitoring of MAP followed by a 7–10 day convalescence period, after which control data was collected for 2 days. Next, mice were randomly subjected to one of three treatments: RDNx, CGx, or sham. MAP and heart rate were recorded for 14 days post‐operatively. Baseline MAP in the three groups was similar (~130mmHg). On post‐operative day 14, MAP in both RDNx (−13 ± 2 mmHg) and CGx (−8 ± 0.3 mmHg) decreased, but was not affected in sham controls (−6 +/− 10 mmHg). The change in heart rate (beats/min) was not different between groups 14 days after surgery (−24 ± 4 in sham, −21 ± 33 in RDNx and −41 ± 18 in CGx). To assess the effect of RDNx on renal cytokines in BPH/2J hypertension, tissues were collected from RDNx and sham‐treated animals two weeks post‐treatment. Tissues were then analyzed by quantitative real time polymerase chain reaction (qRT‐PCR). RDNx decreased mRNA expression of the proinflammatory cytokines interleukin 1 beta and tumor necrosis factor alpha in BPH/2J mice 2 weeks after surgery. Future studies will explore the link between targeted sympathetic ablation, inflammation and change in mean arterial pressure in the hypertensive Schlager mice.Support or Funding InformationThis study was supported in part by the National Institute of Health 5RO1HL11647602 to J.W.O. Other grant support: R01‐HL 067357‐15 and Undergraduate Research Opportunities Program
Impaired Cyclic Nucleotide Signalling in Pre‐Hypertensive Spontaneously Hypertensive Rats: A Dichotomy of Pathways?
Authors: Bardsley Emma , Paterson David J 
Published: November 2023

BackgroundSpontaneously hypertensive rats (SHRs) and young pre‐hypertensive SHRs (pre‐SHR) have enhanced cardiac sympathetic activity; a feature underpinned by abnormal calcium‐dependent exocytosis. The crosstalk between cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in peripheral sympathetic stellate neurons is poorly understood.AimWe used Förster Resonance Energy Transfer (FRET) to test whether there is a difference in cAMP and protein kinase A (PKA) activity in post‐ganglionic sympathetic neurons (PGSNs) obtained from 4‐week pre‐SHR compared with normotensive controls. Furthermore, we sought to determine whether activation of the cGMP‐PKG signalling pathway modulates cytosolic cAMP concentrations and its effector PKA, in sympathetic stellate neurons obtained from Wistar and pre‐SHR.MethodCardiac stellate neurons were isolated from male Wistar rats and pre‐SHR at 4‐weeks. On the day of culture, stellates were infected with either cAMP or PKA reporter adenovirus particles for 24 hours, and FRET experiments were carried out 3–4 days post‐isolation. Data were obtained from neurons expressing FRET biosensors using dual‐emission imaging, where YFP and CFP emission intensities were measured. During imaging, cells were perfused continuously with Tyrode's, or stimulated with forskolin (0.1–25μM) and saturating concentrations of 3‐isobutyl‐1‐methylxanthine (IBMX; 100μM). In alternative experiments, neurons were perfused with 8‐bromoguanosine (8‐br‐cGMP; 100μM) prior to saturation with forskolin (25μM) and IBMX (100μM). All raw percentage FRET changes were subsequently normalised to the maximal FRET change at saturation.ResultsThere was no significant difference between cAMP or PKA activity in response to forskolin administration in 4‐week stellates obtained from Wistar and pre‐SHR; however, cAMP and PKA responses to 8‐br‐cGMP were significantly different in PGSNs from the two strains. In neurons obtained from pre‐SHRs there was no change in PKA in response to 8‐br‐cGMP. Conversely, in Wistar stellate neurons, administration of the cGMP analogue facilitated a rapid increase in PKA activity (66%). Here we show that the responses to 8‐br‐cGMP results in a dichotomy in cyclic nucleotide signalling pathways in PGSNs from young Wistar versus pre‐SHR neurons. These findings suggest that the interaction between the two cyclic nucleotide signalling pathways may differ in PGSNs from the two phenotypes, prior to the onset of hypertension; either as a result of differential phosphodiesterase (PDE) profiles, or physiological uncoupling in response to diverse signalling microdomains.Support or Funding InformationThis work was supported by the Wellcome Trust Ion Channels and Disease (OXION) Initiative
The connectome of rostral ventrolateral medulla C1 neurons
Authors: Le Sheng , Dempsey Bowen , Turner Anita , Allen Andrew , Goodchild Ann , McMullan Simon 
Published: November 2023

The transcription factor Phox2b is co‐expressed on a large proportion of rostral ventrolateral medulla (RVLM) sympathetic premotor neurons. This population is thought to play a key role in the transmission of vasomotor sympathetic drive and represents a major site of convergence for multiple descending and reflex pathways that co‐ordinate sympathetic nerve activity. Elucidating the organization of the circuits that control these neurons is a key research objective. Here we present brain‐wide connectomic maps of neurons that provide monosynaptic drive to RVLM C1 neurons, generated using a two‐step restricted trans‐synaptic viral tracing strategy. Phox2b expressing C1 neurons were first transduced with a lentiviral vector to express a cassette containing the cognate avian receptor TVA and rabies G‐protein. TVA‐expressing neurons were then selectively infected with a reporter‐expressing rabies variant, SADΔG (EnvA)‐RFP, which retrogradely and trans‐synaptically labelled neurons that provide monosynaptic drive to Phox2b‐positive neurons.By precisely targeting rabies injections to the core of the RVLM we were able to restrict rabies ‘seeding’ to small numbers of RVLM C1 neurons immediately caudal to the facial nucleus, and then map the locations of neurons that provide monosynaptic input to the seed population. We observed reproducible patterns of inputs arising from the dorsal, contralateral, and midline medulla, and local RVLM interneurons and neurons likely to reside within the Bötzinger, pre‐Bötzinger, and ventral respiratory groups. Distant inputs were identified in the pons and midbrain, and included previously suspected sites of monosynaptic drive such as the paraventricular nucleus of the hypothalamus.
Maternal protein intake as a determinant of the total number of motor units and muscle fibres in mice
Authors: Vasilaki Aphrodite , Giakoumaki Ifigeneia , Pollock Natalie , Goljanek‐Whysall Katarzyna , McArdle Anne , Sayer Avan Aihie 
Published: November 2023

Age‐related sarcopenia is characterized by reduction in the number of myofibres and an additional weakening of the remaining fibres, resulting in a reduction in muscle mass and function. Studies associate these changes with poor maternal malnutrition. However, very little is known about the effect of the maternal protein intake on the number of motor units in offspring. The aim of this study was to examine the effect of maintaining females on a low‐protein diet on the number of muscle fibres in offspring and whether any changes can be modulated by optimization of the nutrition in early post‐natal stages. Studies were undertaken in Thy1‐YFP16 mice that express yellow fluorescent protein only in neuronal cells. Female mice were fed either a normal (20%) or a low‐protein (5%) diet. Newborn pups were cross‐fostered to different lactating dams (maintained on 20% or 5% diet) within 24 h after birth, generating 4 groups: Normal‐to‐Normal (N‐N), Normal‐to‐Low (N‐L), Low‐to‐Normal (L‐N) and Low‐to‐Low (L‐L). Pups were culled at weaning (21 days) by cervical dislocation and the body weight recorded. One EDL was removed and snap frozen, sectioned and the total number of fibres counted. To visualize the neuromuscular junctions (NMJs), the second EDL muscle was removed and fixed in 4% p‐formaldehyde. Muscles were incubated for 30‐min with 5 μg/mL Alexa 594‐conjugated a‐Bungarotoxin (BTX).Data showed that mice born from dams on 20% diet but fed post‐natally by a foster dam on 5% diet (N‐L) show significant reductions in body size and body weight whereas mice born from dams on 5% diet but fed post‐natally by a dam on 20% diet (L‐N) did not show such changes when compared with pups from dams on 20% diet throughout the in utero and post‐natal periods [(N‐N); N‐N: 6.6±0.3g vs. N‐L: 3.56±0.15g)]. Muscle fibre cross sectional areas (CSAs) and innervation and the total number of muscle fibres were reduced in the N‐L compared with the N‐N group whereas in the L‐N only the total number of muscle fibres where affected (N‐N: 1450±51 vs. N‐L: 1231±67 vs. L‐N: 1270±51). Mice born from dams on 5% diet and fed post‐natally by a dam on a 5% diet (L‐L) show a reduced body size, body weight, muscle size and muscle fibre CSAs compared with the N‐N but these reductions were not as profound as in the N‐L group. Thus, data suggests that, in mice, poor maternal protein intake, either only in utero or only post‐natally, results in a significant loss of muscle fibres and that interventions post‐natally are able to reverse the detrimental effects in utero.Support or Funding InformationSupported by the British Physiological Society
FGGY Carbohydrate Kinase Domain Containing is Upregulated during Neurogenic Skeletal Muscle Atrophy
Authors: De Las Casas Bella , Waddell David 
Published: November 2023

Skeletal muscle atrophy results from a range of physiological conditions, including denervation, corticosteroid exposure and aging. In order to better characterize the molecular genetic events of neurogenic atrophy, the gastrocnemius muscle was isolated from mice following 3 days and 14 days of sciatic nerve denervation. The gene expression profile in the denervated muscle tissue was then analyzed by microarray and compared to control muscle tissue in order to identify novel neurogenic atrophy‐induced genes. The microarray data revealed for the first time that FGGY carbohydrate kinase domain containing (Fggy) is expressed in skeletal muscle and is significantly induced in response to denervation. Bioinformatic analysis of the Fggy gene locus in mice reveals two validated alternative variants with distinct transcription initiation sites. In order to confirm that Fggy is expressed in muscle cells, the cDNA of the two validated alternative splice variants of Fggy were cloned from the C2C12 mouse myoblast cell line. The results presented here in combination with additional research into the transcriptional regulation and function of Fggy will help contribute new insight into the molecular mechanisms of skeletal muscle atrophy. Furthermore the identification and characterization of novel genes that are activated during neurogenic atrophy helps improve our understanding of the molecular and cellular events that lead to muscle wasting and could eventually lead to new therapeutic targets in the future.Support or Funding InformationUniversity of North Florida Transformational Learning Opportunity Grant
Low‐Frequency Electrical Stimulation (Acu‐LFES) attenuates denervation‐induced muscle atrophy by increasing muscle regeneration
Authors: Wang Xiaonan H , Klein Janet D. , Wang haidong 
Published: November 2023

Muscle wasting occurs in a variety of clinical situations including denervation. There is no effective pharmacologic treatment for muscle wasting. In this study, we used a tibial nerve denervation model to test acupuncture plus low frequency electric stimulation (Acu‐LFES) as a therapeutic strategy for muscle atrophy. Acupuncture needles were connected to an SDZ‐II electronic acupuncture device delivering pulses at 20Hz and 1mA, the treatment is 15 minutes daily for 2 weeks. Acu‐LFES prevented soleus and plantaris muscle weight loss and increased muscle cross‐ sectional area in denervated mice. The abundance of Pax7, MyoD, myogenin and embryo myosin heavy chain was significantly increased by Acu‐LFES in both normal and denervated muscle. The number of central nuclei was increased in Acu‐LFES treated muscle fibers. Phosphorylation of Akt was downregulated by denervation leading to a decline in muscle mass; however, Acu‐LFES prevented the denervation‐induced decline by upregulation of the IGF‐1 signaling pathway. Acu‐LFES reduced the abundance of muscle catabolic proteins forkhead O transcription factor and myostatin, contributing to the attenuated muscle atrophy. Acu‐LFES stimulated the expression of macrophage markers (F4/80, IL‐1b and arginase‐1) and inflammatory cytokines (IL‐6, IFNg and TNFa) in normal and denervated muscle. Acu‐LFES also stimulated production of the muscle specific microRNAs miR‐1 and miR‐206. We conclude that increased muscle regeneration is associated with the Acu‐LFES sparing of muscle mass in denervation‐induced skeletal muscle atrophy. Upregulation of IGF‐1, downregulation of myostatin and alteration of microRNAs contribute to Acu‐LFES‐induced myogenesis.Support or Funding InformationNIH/NIAMS: R01 AR060268
Sarcolipin is Upregulated in Response to Soleus Unloading Caused by Tenotomy and Opposes Muscle Atrophy
Authors: Fajardo Val Andrew , Rietze Bradley A , Chambers Paige J , Quadrilatero Joe , Tupling A. Russell 
Published: November 2023

Previous studies have shown that sarcolipin (SLN), a small inhibitor of the sarco(endo)plasmic reticulum Ca2+‐ATPase (SERCA) pump, is upregulated in conditions of muscle atrophy. To date, however, the role of SLN in muscle atrophy remains unknown. In another unpublished study from our laboratory, we mechanically overloaded plantaris muscles by performing soleus and gastrocnemius tenotomy (surgical transection of the tendon), and found that SLN is critical in mediating muscle growth and fiber type remodeling. In this study we questioned the role of SLN in the tenotomized soleus, which is a model of muscle unloading known to cause muscle degeneration, atrophy, and a fast‐glycolytic muscle phenotype. We hypothesized that in the absence of Sln, soleus muscles would exhibit greater muscle atrophy and an accelerated slow‐to‐fast fiber type shift. Our results show that 2 weeks after tenotomy, SLN protein was upregulated 14‐fold (P ≤ 0.05) in WT muscle compared with sham. Furthermore, removing this 14‐fold upregulation led to a greater percent reduction in soleus muscle mass relative to body weight in SlnKO mice compared with WT (WT, −51.0 ± 3.5% vs. SlnKO, −59.0 ± 1.8%, P ≤ 0.05). In addition, significant reductions in myofiber cross‐sectional area were found in WT mice (−29% to −38%, P ≤ 0.05, two‐way repeated ANOVA), and also in SlnKO mice, but perhaps to a greater extent (−33% to −42%, P ≤ 0.05, two‐way repeated ANOVA). With respect to the slow‐to‐fast fiber type shift, the WT mice exhibited a partial shift in response to tenotomy with a significant decrease and trending increase in type IIA (P ≤ 0.05) and type IIX (P = 0.10) fiber percent, respectively. In contrast, in response to tenotomy, SlnKO mice exhibited an accelerated slow‐to‐fast fibre type shift with a significant decrease in type I (P ≤ 0.05) and increase in type IIX (P ≤ 0.05) fiber percent, respectively. Since calcineurin stabilizes the deleterious effects of reduced mechanical loading, we examined the phosphorylation status of its well‐known substrate nuclear factor of activated T‐cell (pNFAT). Our results show that, in response to tenotomy, WT soleus muscles had significantly lower pNFAT compared with sham (−57%, P ≤ 0.05); however pNFAT was not different between SlnKO sham and tenotomized soleus muscles. Thus, our results show that SLN upregulation in tenotomized soleus muscles is required to counteract muscle atrophy and the transition to the fast, glycolytic fiber phenotype, and may do so through its stimulatory effect on calcineurin.Support or Funding InformationThis work was supported by the Canadian Institutes of Health Research (CIHR; MOP 86618 and MOP 47296 to A.R.T).
Spatiotemporal Organization Of Signaling: From Plasma Membrane To Chromatin
Authors: Gingras Anne‐Claude 
Published: November 2023

Compartmentalization is essential for all complex forms of life. In eukaryotic cells, membrane‐bound organelles, as well as a multitude of protein‐ and nucleic acid‐rich subcellular structures, maintain boundaries and serve as enrichment zones to promote and regulate protein function. Consistent with the critical importance of these boundaries, alterations in the machinery that mediate protein transport between these compartments has been implicated in a number of diverse diseases. Signaling molecules are no exception, and must be targeted to specific locations for proper activation in time and place.Understanding the composition of each cellular “compartment” (be it a classical organelle or a large protein complex) remains a challenging task. For soluble protein complexes, approaches such as affinity purification other biochemical fractionation coupled to mass spectrometry provides important insight, including on the temporal regulation of signaling, but this is not the case for detergent‐insoluble components. Classically, both microscopy and organellar purifications have been employed for identifying the composition of these structures, but these approaches have limitations, notably in resolution for standard high‐throughput fluorescence microscopy and in the difficulty in purifying some of the structures (e.g. p‐bodies) for approaches based on biochemical isolations. Prompted by the recent implementation in vivo biotinylation approaches such as BioID, we have begun the systematic mapping of the composition of various subcellular structures, using as baits proteins (or protein fragments) which are well‐characterized markers for a specified location. We report here our low‐resolution map of a human cell (currently defined from BioID profiling of 100 marker proteins), including various membrane compartments, cytoskeletal structures and nuclear subdomains. We will also introduce a higher resolution map of RNA‐containing cellular structures, including the p‐bodies and the stress granules that regulate mRNA stability, and new data on signaling pathways that span insoluble compartments. We demonstrate in vivo biotinylation to be a scalable approach capable of revealing protein complexes as well as their association into larger structures.Support or Funding InformationWork in the Gingras lab was primarily supported by the Canadian Institutes for Health Research (Foundation grant) and the Natural Sciences and Engineering Research Council of Canada (Discovery grant). Additional funding was provided by Genome Canada through Ontario Genomics.
Overexpression of Muscle Ring Finger 1 Reduces Mitochondrial Volume in Cardiomyocytes
Authors: Parikh Chirag , Kobayashi Satoru , Gerdes Martin , Willis Monte S , Liang Qiangrong 
Published: November 2023

ObjectivesMuscle Ring Finger 1 (MuRF1) is an ubiquitin E3 ligase that participates in atrophy of cardiac myocytes, and when upregulated, increases risk of dilated cardiomyopathy. While many studies have shown the regressive atrophy that MuRF1 participates in, more recent studies also indicate that increased expression of MuRF1 results in broad disruption of metabolic functions in cardiac tissues and in particular, mitochondria. However, it is unclear what role MuRF1 plays with mitochondrial regulation. Since the energy requirement in cardiac muscle cells is high, mitochondrial homeostasis is tightly regulated by multiple processes which include fusion, fission, mitophagy and biogenesis. This study aimed to determine whether MuRF1 plays a role in regulation of these processes by examining the morphological changes of mitochondria and their relationship with cell viability.MethodsH9C2 Cardiomyoblast cell line was pretreated with an adenovirus‐encoded mitochondrial‐targeting protein, mtRosella, a construct that results in fluorescence of mitochondria, allowing examination of morphology and mitophagy. Following this, these cells were infected with an adenovirus encoding MuRF1 to increase the protein expression levels of MuRF1. Change in MT morphology was determined with confocal microscopy. Morphological descriptors (count, average size, major and minor axes) were measured using ImageJ analysis software to describe changes in the degree of mitochondria size, fragmentation, and mitophagy. Additionally, propidium iodide staining was used in an identical setup to determine if MuRF1 overexpression affects cell viability.ResultsMorphometric analysis demonstrated that overexpression of MuRF1 in H9C2 cells did not change the count of mitochondria, but decreased the size of mitochondria. Both major and minor axes were decreased in the overexpression group. In addition, mitophagy levels did not differ in the overexpression group versus the control. Finally, propidium iodide staining did not show an increase in cell death in the overexpression group, a finding that agrees with other study findings. Further study is needed to determine if MuRF1 affects mitochondrial biogenesis to reduce the mitochondrial size.ConclusionOverexpression of MuRF1 is sufficient to reduce mitochondrial size but it does not have an effect on mitochondrial number and mitophagy. The reduced mitochondrial size may reduce the overall capacity of mitochondrial metabolic function and increase the sensitivity of the cardiomyocyte or the heart to pathological stresses such as ischemia and chemotherapy.Support or Funding InformationNIH Grant 1R15HL120027‐01A1
Diet Restriction Exacerbates Memory Loss in Alzheimer's Disease Drosophila melanogaster Model Flies
Authors: Damschroder Deena Jan , Paddock Brie 
Published: November 2023

Major risk factors for the development of Alzheimer's disease (AD) include aging and diabetes. Although among the top ten leading causes of death in the U.S., there is still no cure for AD (Ho, 2004). It is believed that diet restriction (DR) and caloric restriction (CR) increase lifespan due to the fact that they slow the aging process and oxidation process, two processes which contribute to AD (Cline, 2000). It is unclear whether the extension of lifespan in humans and animal models corresponds with a delay in degeneration associated with aging (Burger et al 2010). This study uses the aversive phototaxis assay (Ali et al., 2011) to examine how diets consisting of reduced sucrose and reduced yeast affect the memory in a Drosophila model of AD. Our results support the hypothesis that nutrient availability plays a key role in the pathogenesis of AD, but that CR is not necessarily protective against neuronal deterioration.Support or Funding InformationCollege of Arts and Sciences, Arcadia University