bluuebunny/crossref_metadata_2025_split huggingface dataset:
A High Fat Diet in Pregnancy Modifies Mouse Maternal Behaviour
Authors: Moazzam Showall , Noorjahan Noshin , Jarmasz Jessica S. , Jin Yan , Siddiqui Tabrez J. , Cattini Peter A. 
Published: April 2020

BackgroundAbout a third of pregnant women of age 20–39 are obese, which carries significant risks for the mother and fetus, and adversely impacts pregnancy outcome. Specifically, women with obesity are at increased risk for peripartum depression. Maternal behaviour in mice is influenced by changes in hormone signaling in pregnancy, which is associated with effects on adult neurogenesis in the brain. Thus, we used mouse as a model system to gain further insight into the possible relationship between overeating/obesity and brain physiology and maternal behaviour.ObjectiveTo assess the ability of a high‐fat diet (HFD) versus a regular chow diet (CD), starting up to 10 weeks pre‐pregnancy, to modify glucose clearance before and during pregnancy and affect maternal behaviour in the CD1 mouse.ApproachTwo groups of 3–4 week‐old female CD1 mice were fed a HFD (fat=60 kcal%; carbohydrate=20 kcal%; protein=20 kcal%) or CD (fat=14 kcal%; carbohydrate=60 kcal%; protein=26 kcal%) and maintained on their respective diets throughout the study and weighed periodically. After at least 4 weeks of feeding on their diets, mice were allowed to breed. Glucose tolerance was tested using 2 g/kg of i.p. glucose at gestational day (GD) ‐1) after fasting (16 hours‐overnight) as well as during pregnancy at GD16.5. An even number of pregnant and non‐pregnant females were selected for each diet for maternal behaviour testing. Tests include an assessment of nest building at GD16.5–17 (use of nesting material and nest quality), and after birth pup retrieval at postpartum day (PD) 3, 4 and 5 (time of retrieval of each of the four pups within six minutes) using video capture.ResultsThe HFD led to a significant increase in weight relative to mice fed a CD. HFD impaired glucose‐load clearances at GD ‐1 and 16.5 (p<0.05) compared to mice fed a CD. Mice fed on HFD performed poorly in the nest building task (p<0.01) as well as demonstrated a reduced completion rate on the pup retrieval test on PD3 (CD=8/10 vs. HFD 2/9 mice) but their retrieval response latency was improved by PD4 (CD=8/10 vs. HFD 8/9 mice) and PD5 (CD=7/10 vs. HFD 7/9 mice).ConclusionsInitial observations suggest that a HFD for at least 4 weeks before and during pregnancy results in overweight CD1 mice with impaired glucose clearance, and a negative effect on maternal behaviour as assessed by nest‐building during pregnancy and pup retrieval postpartum; however, with regard to the latter, mice on the HFD show the ability to learn. Additional behavioural tests for locomotion, anxiety, risk avoidance and object recognition memory during or after pregnancy, as well as associated changes in hormonal signaling and adult neurogenesis are also currently under investigation.
Cannabinoid receptor‐1 expressing interneurons require postsynaptic dystroglycan for targeting during postnatal brain development
Authors: Miller Daniel S. , Wright Kevin M. 
Published: April 2020

Dystroglycan is a transmembrane glycoprotein highly expressed in muscle and brain that links the extracellular matrix to the actin cytoskeleton through its two subunits, a heavily glycosylated extracellular subunit alpha dystroglycan (a‐DG), and the membrane spanning beta‐dystroglycan (b‐DG). Glycosylation of dystroglycan by at least 18 enzymes is essential for its ability to bind extracellular ligands throughout development. Mutations in genes encoding glycosyltransferases such as B4gat1 and ISPD reduce dystroglycan function and cause a spectrum of congenital muscular dystrophies characterized by muscle weakness, brain malformations, and cognitive deficits. In the brain, dystroglycan is expressed by both glia and excitatory neurons, but its specific function in neurons has remained elusive. Recently, neuronal dystroglycan was discovered to be important for the formation of presynaptic cannabinoid receptor 1 (CB1R) synapses derived from cholecystokinin (CCK) interneurons, a population of inhibitory cells in the forebrain. However, the mechanism by which dystroglycan regulates the development of CCK/CB1R+ inhibitory synapses remains unknown. In the present study, we use multiple mouse lines to determine how dystroglycan regulates CB1R+ synapse development, including mouse models of dystroglycanopathy (B4gat1, ISPD), conditional genetic deletion of dystroglycan from neurons and glia (Dag1‐cKO: Nex‐Cre, Emx‐Cre, Nestin‐Cre), and a mouse lacking the intracellular signaling domain of dystroglycan (Dag1ICD). We found that deletion of dystroglycan specifically from excitatory neurons resulted in the loss of nearly all presynaptic CB1R+ terminals within the first week after birth. Surprisingly, deletion of dystroglycan from both neurons and glia using Nestin‐Cre or Emx‐Cre resulted in abnormal targeting of CB1R+ terminals. We also find that maintenance of CB1R+ terminals in adulthood does not require full glycosylation of a‐DG or the intracellular signaling domain of b‐DG. Collectively, these results suggest that dystroglycan may be required for the proper targeting of CB1R+ synapses during postnatal brain development.Support or Funding InformationNINDS R01 NS091027 (KMW)NINDS F31 NS108522 (DSM)ARCS Fellowship (DSM)Tartar Fellowship (DSM)
Effect of ankle joint position on triceps surae motor unit firing rates
Authors: Hali Kalter , Zero Alexander M. , Fanous Jacob , Rice Charles L. 
Published: April 2020

The triceps surae is an interesting model to study the effect of muscle length changes on motor unit properties for two reasons. First, the gastrocnemii components show lower motor unit discharge rates (MUDRs) when shortened by knee joint flexion as compared to an extended knee joint, whereas all other muscles studied display either higher or similar MUDRs in a shortened compared to a lengthened position. Second, the soleus receives strong afferent feedback due to its predominantly type I muscle fiber composition indicating that muscle length changes may have a great effect on its motor unit properties. The limited previous studies have not explored how changes in ankle joint position affect the triceps surae muscles. Thus, the purpose of this study was to compare MUDRs of the bi‐articular medial gastrocnemius (MG) and mono‐articular soleus at two ankle joint positions, 30° dorsiflexion and 20° plantar flexion, during the common task of plantar flexion. Four young, healthy men (~24 years old) were seated upright in a leg dynamometer with both the hip and knee joint angles at 90°. Subjects performed two ~3s isometric plantar flexion maximal voluntary contractions (MVC) at each ankle joint position. Tungsten electrodes were then used to record MUDRs from the MG and soleus during separate steady state 3–10s isometric plantar flexion contractions at 25, 50, 75, and 100% MVC at one ankle joint position. After a series of contractions, the ankle joint angle was changed and the subjects performed another series of plantar flexion contractions at each torque level. Initial ankle joint position and the order of contractions performed were randomized prior to each testing session. Subjects visited the lab multiple times to repeat the intervention in order to sample from many motor units. The mean MVC torque was 53% lower in the shortened (20° plantar flexion; 105Nm) compared to the lengthened (30° dorsiflexion; 223Nm) position. A total of 487 motor units from the MG (n=228) and soleus (n=259) were identified. Mean MG MUDRs at 25, 50, 75 and 100% MVC were lower by 8, 0, 17 and 14%, respectively in the dorsiflexed compared to the plantar flexed position. Similarly, mean soleus MUDRs were lower by 8, 12, 25 and 25% at 25, 50, 75 and 100% MVC, respectively in the dorsiflexed compared to the plantar flexed position. These preliminary findings indicate that shortening the MG and soleus by placing the ankle joint in a plantar flexed position leads to higher MUDRs as compared to a dorsiflexed position. This may serve as a compensatory mechanism for the decreased torque producing capability of the triceps surae in a shortened (plantar flexed) position.Support or Funding InformationFunded by NSERC.
The role of bilirubin and heme metabolism in neuronal stress signaling
Authors: Paul Bindu Diana , Vasavda Chirag , Kothari Ruchita , Malla Adarsha , Ricco Cristina , Snowman Adele , Tokhunts Robert , Sedlak Thomas W. , Snyder Solomon 
Published: April 2020

Bilirubin is amongst the most frequently measured peripheral metabolites, yet its roles in vivo are not totally understood. Believed to be a marker for liver function, it is now increasingly evident that bilirubin plays vital roles in the brain. Bilirubin is synthesized by Biliverdin reductase (BVR) from biliverdin, which in turn is derived from heme. BVR exists as two isoforms, BVR‐A and BVR‐B, of which BVR‐A is enriched in the brain. In addition to its role in bilirubin generation, BVR‐A is a kinase and transcription factor, and participates in several signaling pathways. Besides, these activities, the BVR pathway plays significant roles in maintenance of redox homeostasis in cells. Cell culture studies have shown that depletion of BlvrA, the gene encoding BVRA causes elevated oxidative stress and associated cellular damage. Using BlvrA−/− mice, we show that BVRA is the major enzyme responsible for bilirubin production. The gall bladders of these mice are green due to accumulation of biliverdin and inability to produce bilirubin. We analyzed the effects of bilirubin depletion in the brain using these mice. Paucity of bilirubin leads to elevated superoxide production in the brain and altered cytoprotective response to stress stimuli. These mice are defective in several antioxidant defense pathways. BlvrA mice also display a variety of behavioral abnormalities including cognitive deficits. We further show that bilirubin is a potent and direct superoxide scavenger in vivo, which accounts for its role in maintenance of redox balance. Treatment of mice with N‐methyl D‐aspartate (NMDA), an excitotoxin, results in increased neuronal death and larger lesions in BlvrA−/− mice. NMDA receptor activation is known to elevate superoxide production via the NADPH oxidases, enzymes which are known to be inhibited by the BVR‐bilirubin pathway. Taken together, our findings uncover important roles for BVR in neuroprotective processes. Modulating the BVR/bilirubin pathway may offer therapeutic benefits in neurodegenerative diseases involving redox imbalance.Support or Funding InformationNIH grants
MH18501(to S.H.S.)
Dysregulated hydrogen sulfide metabolism links aberrant neuronal stress responses and neurodegeneration in Huntington's disease
Authors: Paul Bindu Diana , Snyder Solomon H. 
Published: April 2020

Hydrogen sulfide (H2S) is a gaseous signaling molecule that plays central roles in a myriad of physiological processes ranging from response to oxidative stress and transcriptional regulation. Hydrogen sulfide is synthesized endogenously from the semi‐essential amino acid cysteine via the reverse transsulfuration pathway. Thus disrupted cysteine metabolism may also lead to aberrant H2S signaling. One of the modes by which hydrogen sulfide signals is by a posttranslational modification designated as sulfhydration/persulfidation, which occurs on reactive cysteine residues on target proteins, where the reactive SH group is converted to an SSH group. Sulfhydration is a highly prevalent modification which modifies the structure and/or activity of target proteins. Research on H2S and persulfidation is still in its infancy. We show here that H2S is generated in response to stress stimuli such as Golgi stress and oxidative stress in neurons, which modulates sulfhydration levels to modulate signaling pathways. We further show that these cytoprotective stress responses are compromised in striatal cell culture model and the R6/2 and Q175 mouse models of Huntington’s disease (HD). We have shown previously that the biosynthetic enzyme for cysteine and H2S in neurons, cystathionine g‐lyase (CSE) is depleted in HD and mediates neurodegeneraton. HD is a neurodegenerative disease which is triggered by expansion of polyglutamine repeats in the protein huntingtin, which causes it to aggregate and elicit multi‐system toxicity. Restoring H2S balance in cells mitigates neuronal dysfunction in neurodegenerative diseases such as HD. A screen for regulators of the transsulfuration pathway has resulted in identification of compounds that modulate cysteine balance and disease progression in HD.Support or Funding InformationUnited States Public Health Service (USPHS) grants
DA000266 and
MH18501 to S.H.S.
Monitoring the activity and screening for selectivity of various classes of cAMP‐Phosphodiesterases (cAMP‐PDEs) using a homogenous HTS formatted bioluminescent platform
Authors: Goueli Said , Hsiao Kevin , Mondal Subhanjan , Zegzouti Hicham 
Published: April 2020

Age associated decline in cognitive functioning present a monumental problem as manifested in the appearance of neurodegenerative diseases such as dementia, Alzheimer diseases, depression, and schizophrenia. Furthermore, the FDA approval of PDE‐5 inhibitors for erectile disfunction and the utility of these inhibitors in treatment of serious diseases such as pulmonary hypertension validates these group of enzymes as significant drug targets. The need to monitor the activity of these enzymes in a homogenous, easy to perform and highly reproducible, and sensitive format will be highly desirable. Towards this goal, we have developed a bioluminescent assay that monitor their activity using very low enzyme concentrations in 384‐well formats, and easy to perform protocol. We have used this assay to monitor the activity of several cAMP‐PDES such as PDE3, PDE4, and PDE10 as examples and were able to detect their activity using nanogram of enzyme concentrations. The assay enabled us to check for selectivity of various known inhibitors that are selective for their targeted enzyme. We also generated IC50 (inhibitor concentration that inhibit enzyme activity by 50%), that are similar to those reported in the literature. This assay can be also used to profile several inhibitors against various cAMP‐PDEs and thus, it may facilitate the development of novel therapeutics towards these enzymes.Support or Funding InformationThis research was supported by Promega Corp.
“Kidney and urinary metabolic profiles of monosodium glutamate consumption in Wistar rats”
Authors: Nahok Kanokwan , Thanan Raynoo , Silsirivanit Atit , Selmi Carlo , Cha’on Ubon 
Published: April 2020

While its effects on human health are still debated, monosodium glutamate (MSG) has been widely used globally for at least five decades. Since there are no reliable biomarkers of MSG consumption in human, the monitoring of harmful effects of MSG intake on human health is not feasible. We aim to investigate the kidney and urinary metabolic profiles of MSG consumption in animals. Adult male Wistar rats were assigned into 4 groups, including receiving water with 1 g% MSG added, 0.34 g% NaCl added, 2.4 g% NaHCO3 and normal drinking water. Urine chemistries were analyzed before and after 2 weeks of MSG‐treatment. Urinary metabolic profile was determined after MSG supplementation using NMR technique. Kidney tissue were also investigated for ion‐exchanger genes expression including its metabolites. The results revealed that the MSG‐ and alkaline‐treated groups had significantly higher levels of urine pH, urine sodium and bicarbonate compared to controls. This corresponds to the lower expression of ion‐exchanger genes (CAII, NBC1, and AE1) involved in bicarbonate reabsorption in kidney of MSG‐ and alkaline‐treated groups compared to controls. The kidney metabolic profile of MSG and control groups were also investigated. We found that trimethylamine had significantly higher level in MSG group, whereas the higher levels of pyridoxine found in controls. In conclusion, MSG‐treated rats are able to induce alkaline urine, reduce bicarbonate reabsorption and generate the urinary metabolic profiles similar to that of alkali supplemented animals. Moreover, the urinary and kidney metabolomics revealed that there is a connection between the uremic toxin and MSG consumption in rats.Support or Funding InformationThe Royal Golden Jubilee Ph.D. Program (RGJ‐Ph.D. Program) (PHD/0124/2558). The Invitation research fund (IN62137), Faculty of Medicine, Khon Kaen University, Thailand.
Inhibiting Cytoskeletal Remodeling Increases Tension Cost in Airway Smooth Muscle
Authors: Jensen Cole , Kafaji Mustafa , Han Young , Sieck Gary 
Published: April 2020

Cytoskeletal remodeling in smooth muscle occurs with activation and involves actin polymerization. Remodeling of the cortical cytoskeleton allows tethering of contractile proteins and force transmission to the extracellular matrix. Smooth muscle contraction involves cross‐bridge cycling and ATP hydrolysis, which are both sensitive to loading. During isometric activation, the rate of ATP hydrolysis is initially high but declines with time reaching a steady‐state, while peak force is maintained. Thus, tension cost, i.e., the rate of ATP hydrolysis per unit of force, decreases over time, reflecting increased efficiency of smooth muscle activation. We hypothesize that the time‐dependent decrease in ATP hydrolysis rate and tension cost is due to cytoskeletal remodeling and an increase in internal loading on cross‐bridges. In permeabilized porcine airway smooth muscle (ASM) strips, isometric force and ATP hydrolysis rate were simultaneously measured after maximum Ca2+ activation (pCa 4.0). From each animal, two ASM strips were tested: 1) Inhibition of actin polymerization and cytoskeletal remodeling using Cytochalasin‐D (Cyto‐D; treated (1 μM for 30 min); and 2) Untreated controls. Compared to untreated controls, Cyto‐D‐induced inhibition of actin polymerization reduced both peak and steady‐state isometric force by ~40%, while peak and steady‐state ATP hydrolysis rate increased by ~30% and ~20%, respectively. As a result, at peak and steady‐state, tension cost increased by ~100% and ~60%, respectively, following Cyto‐D treatment. These results support our hypothesis that the time‐dependent decrease in ATP hydrolysis rate reflects an increase in internal load on cross‐bridges via cytoskeletal remodeling. Cyto‐D inhibition of cytoskeletal remodeling impairs contractile protein tethering and thus reduces internal loading, resulting in faster cross‐bridge cycling and increased ATP hydrolysis rate.Support or Funding InformationSupported by NIH grant HL126451(GCS), HL150890 (GCS) and the Mayo Clinic
Mechanisms Underlying TNFα‐Induced Hyperreactivity in Airway Smooth Muscle
Authors: Kafaji Mustafa , Jensen Cole , Han Young , Delmotte Philippe , Dogan Murat , Sieck Gary 
Published: April 2020

Inflammation and pro‐inflammatory cytokines (e.g., TNFα, IL‐13) induce airway smooth muscle (ASM) hyper‐reactivity and remodeling characteristic of asthma. We hypothesized that exposure to TNFα (and IL‐13) increases isometric force generation in porcine ASM via several underlying mechanisms: 1) increasing sensitivity to ACh stimulation; 2) enhancing the cytosolic Ca2+ ([Ca2+]cyt) response to ACh; 3) increasing the Ca2+ sensitivity of force generation; 4) enhancing the Ca2+‐dependent phosphorylation of myosin regulator light chain (rMLC); 5) promoting expression of non‐muscle rMLC; 6) increasing actin and myosin heavy chain (MyHC) content (i.e., the number of contractile units); and/or 7) promoting cytoskeletal remodeling (actin polymerization). Studies were performed on intact ASM strips (~1 mm wide × ~5 mm long) dissected from porcine tracheas obtained from a local abattoir. The ASM strips were placed in PSS with and without TNFα (100 ng/ml) for 24 h. The ACh concentration dependence of force generation ASM was determined (ACh range from 10 nM to 1mM), and the EC50 (i.e., the ACh concentration that produces 50% of maximal ASM force) was determined. In control, untreated ASM, the EC50 for ACh was 2.6 μM compared to 1.3 μM following TNFα treatment. We found that across all ACh concentrations, ASM force increased after TNFα treatment with an ~50% increase in maximum ASM force. The [Ca2+]cyt response induced by the EC50 [ACh] was similar in control and TNFα treated ASM. Thus, with an increase in force and no effect on [Ca2+]cyt, there was an apparent increase in Ca2+ sensitivity of force after TNFα treatment. However, in both control and TNFα treated ASM, the extent of rMLC phosphorylation induced by ACh stimulation was not affected by TNFα treatment. Importantly, the extent of rMLC phosphorylation at the ACh EC50 was comparable between control and TNFα treatment indicating no change in Ca2+ sensitivity. The expression of non‐muscle rMLC (determined by 2D gel electrophoresis) was also unaffected by TNFα treatment. Total actin and MyHC concentrations increased by ~45% following TNFα treatment; thus, the number of contractile units contributing to force increased. This was reflected by a marked increase in the Ca2+ activation of ATP consumption (cross‐bridge cycling) of ASM following TNFα treatment. Cytoskeletal remodeling was evaluated by ACh‐induced actin polymerization (F‐/G‐actin ratio) but was found to be unaffected by TNFa treatment. Together, our results show that two primary mechanisms underlie the marked increase in ASM force generation induced by 24‐h TNFα exposure: 1) an increase in ACh sensitivity, and 2) an increase in actin and MyHC concentrations (number of contractile units).Support or Funding InformationSupported by NIH grant HL126451 (GCS) and HL150890 (GCS)