bluuebunny/crossref_metadata_2025 huggingface dataset:
Knock‐down of ADAM17 in glutamatergic or pre‐autonomic neurons attenuates development of neurogenic hypertension
Authors: Basting Tyler M , Xu Jiaxi , Sriramula Srinivas , Murkerjee Snigdha , Lazartigues Eric
Published: November 2023

Rationale and objectives

We have previously reported that DOCA‐salt‐induced neurogenic hypertension is associated with a reduction of Angiotensin Converting Enzyme 2 (ACE2) and an increase in A Disintegrin And Metalloprotease 17 (ADAM17) activity in the hypothalamus. Blocking Angiotensin‐II type 1 receptors or silencing ADAM17 in the CNS prevented hypertension. Since ADAM17 is known to be expressed on different cell types in several brain regions and can be activated in multiple ways, we generated several specific knockout mice targeting ADAM17 in neurons, astrocytes and microglia. In one of these models, we tested the hypothesis that glutamatergic neurons expressing ADAM17 mediate ACE2 shedding from the cell membrane in neurogenic hypertension. Secondly, through selective knock‐down of ADAM17 in Sim1‐positive neurons we examined its role in pre‐autonomic neurons.

Methods

Primary neuronal cultures were used to substantiate glutamate's role in up‐regulating ADAM17 activity. In vivo, ADAM17 knock‐down mice (ADAM17 floxed crossed with either Vesicular Glutamate Transporter 2 ‐ cre or Sim1 – cre recombinase mice), and control littermates were implanted with telemetry probes for continuous recording of blood pressure (BP) and heart rate (HR) (N = 26 control; N = 3/group experimental). After baseline data were collected the mice underwent DOCA‐salt treatment (DOCA 1 mg/g body weight sc + 1% saline po) for 18–20 days.

Results

Primary neurons exposed to glutamate showed increased expression of ADAM17 activity on the cell membrane (24.5±5%). Glutamatergic ADAM17 knock‐down animals, Sim1 ADAM17 knock‐down animals, and their control littermates showed increased BP after DOCA‐salt treatment (Control: +30 ±3 mmHg; ADAM17fl/flvGlut2: +10 ±4 mmHg; ADAM17fl/flSim1: +21.4 ±5). Importantly, mean arterial pressure and HR were significantly lower in mice with ADAM17 knocked‐down from glutamatergic neurons or Sim1 neurons after DOCA‐salt treatment compared to the controls (p<0.01 for all comparisons).

Conclusions

ADAM17 expression on glutamatergic neurons or Sim1 positive neurons does not influence BP and HR during normal resting conditions. However, this is the first evidence showing that these neuronal populations of ADAM17 positive cells are playing a critical role in mediating hypertension. Under DOCA‐salt‐induced neurogenic hypertension BP and HR both increase via pathways involving glutamatergic and Sim1 neurons with ADAM17.

Support or Funding Information

NIH: HL093178 and GM106392; AHA: 12EIA8030004
Whey Protein Improves Glucose Uptake Following Exercise via DPP‐IV and IL‐6
Authors: Neidert Leslie E , Kluess Heidi A
Published: November 2023

Following a bout of exercise, glucose is taken up from the blood by the muscle as a fuel to provide energy. This occurs via translocation of GLUT4 to the muscle membrane. Interleukin 6 (IL‐6) is a modulator of GLUT4 translocation, but this can be altered by the myokine, dipeptidyl peptidase IV (DPP‐IV). The purpose of this study was to investigate glucose uptake following exercise with supplementation and the role of DPP‐IV and IL‐6 in its modulation.

Twenty‐three college‐aged participants were randomly assigned to one of three supplementation conditions (CTL: water, WPI: whey protein isolate, and CHO: fructose beverage; WPI and CHO beverages were isocaloric). On the Baseline Visit, participants completed an Oral Glucose Tolerance Test (OGTT) with no exercise or supplementation. Their Blood Glucose was monitored every 10 minutes until they “cleared” the glucose (Blood glucose<140, ADA). On their second and third visits, participants were asked to consume their supplement beverage then complete a maximal treadmill protocol until volitional fatigue. A second OGTT was completed on the second visit, and blood samples were collected via venipuncture on the third visit for IL‐6, Insulin and DPP‐IV. IL‐6 and insulin were determined via ELISAs, and DPP‐IV activity was determined by fluorescent assay.

Glucose uptake was significantly increased following exercise in the WPI group (Glucose AUC: WPI+Rest= 10600±4589mg/dl*time and WPI+EX= 5993±1013mg/dl*time; p=0.03), but not in the CTL or CHO groups. Additionally, glucose appearance (Peak‐Baseline) was decreased in the WPI group following exercise (WPI+Rest= 79±31mg/dl and WPI+EX= 40±19mg/dl; p=0.006). IL‐6 and DPP‐IV were both significantly increased in the WPI group after exercise (IL‐6: WPI+Rest= 7.72±12.06pg/ml and WPI+EX= 8.12±12.25pg/ml; p=0.004; DPP‐IV: WPI+Rest= 42.29±9.08U/L and WPI+EX=50.40±8.61U/L; p=0.008), and only IL‐6 was significantly increased following exercise in the CTL group (CTL+Rest=1.16±0.87pg/ml and CTL+EX= 1.63±0.86pg/ml; p=0.04). Insulin increased with all groups from rest following exercise (p<0.05), but there were no condition differences.

Whey protein supplementation potentiated glucose uptake possibly via IL‐6 modulated GLUT4 translocation. Because DPP‐IV was significantly increased in the WPI group only, it is possible that this was in response to the IL‐6 increase, but it did not seem to have a negative effect. This has important implications in supplementation and fuel usage during exercise, and future research should investigate the release of DPP‐IV from the muscle in response to exercise and whey protein and its interaction with IL‐6 in the interstitial space.

Support or Funding Information

This study was funded by the Auburn University College of Education Seed Grant
Changes in Osteoprotegerin and Sclerostin Across a Training Season in Olympic Female Rowers
Authors: Kurgan Nigel Kilty , Pepper Connor , Logan‐Sprenger Heather , Falk Bareket , Klentrou Panagiota
Published: November 2023

Exercise training is generally associated with an increase bone mineral density (BMD) but this adaptation is reversed during extended periods of intense training. Furthermore, examination of serum markers of bone turnover has shown an unbalanced increase in bone resorption over bone formation during high volume training. However, the molecular events that precede these changes in bone turnover remain unclear. One pathway related to mechanical loading is the Wnt signalling pathway. Osteoprotegerin (OPG) is a transcription product of Wnt signalling leading to inhibition of bone resorption. Sclerostin (SOST) is an inhibitor of Wnt signalling leading to reduced formation. Therefore, the purpose of this project was to monitor changes in OPG and SOST at times of different training volumes during the pre‐Olympic training season in female rowers. Insulin like growth factor (IGF‐1) and leptin, two other factors that are sensitive to training and have been associated with Wnt signalling were also examined. Blood samples were drawn from female heavy‐weight rowers (n=15, 27.0 ± 0.8 y, 80.9 ± 1.3 kg, 179.4 ± 1.4 cm) at baseline (T1 – 11 months pre‐Olympic Games) and following 1 (T2), 2 (T3), 6 (T4), 7 (T5) and 9 months (T6). Serum was analyzed by Multiplex assays (EMD Millipore, Toronto, CAN). Total weekly training volume was recorded over the week prior to each time point. BMD was measured at multiple sites by dual energy X‐ray absorptiometry at T1 and T6. OPG decreased significantly from T2 to T6 (−28.7%, p<0.05) and SOST levels were increased at T5 compared to T6, T4, T3 and T2 (993.1 vs. 741.0, 709.3, 759.7 and 774.2 pg/mL respectively, p<0.05). IGF‐1 was not changed over time. Leptin increased from T1 to T6 (+84%, p<0.05). Weekly training volume prior to T1 through T6 was 1020, 730, 1270, 1135, 1165 and 1200 min/wk, respectively. No change in BMD was observed at any bone site from T1 to T6. Therefore, over the course of the training season, OPG concentrations decreased while leptin and SOST concentrations increased, suggesting an increased bone formation and decreased bone resorption. In summary, bone biochemical markers were affected during the pre‐Olympic training season in female rowers, but BMD remained unchanged. However, the pattern of changes in osteokines, reflecting dynamic deviations in bone remodelling were not sensitive to changes in training volume.

Support or Funding Information

Canadian Sports Institute
The Role of Rapamycin‐Insensitive mTOR Signaling in the Regulation of Muscle Protein Synthesis in a Rat Model of Resistance Exercise
Authors: Ogasawara Riki , Suginohara Takeshi
Published: November 2023

Resistance exercise (RE) activates signaling by the mammalian target of rapamycin (mTOR), and it has been suggested that rapamycin‐sensitive mTOR signaling is necessary for the increase in muscle protein synthesis (MPS) after RE. However, recent studies have reported that rapamycin does not completely inhibit the RE‐induced increase in MPS, suggesting that rapamycin‐sensitive mTOR‐independent (rapamycin‐insensitive mTOR and mTOR‐independent) mechanisms contribute to this event. The aim of this study was to investigate whether rapamycin‐insensitive mTOR signaling plays a role in the regulation of RE‐induced increase in MPS. The right gastrocnemius muscle of male Sprague‐Dawley rats aged 11 weeks was isometrically contracted via percutaneous electrical stimulation (100Hz, 5 sets of ten 3‐s contractions, 7‐s rest between contractions, 3 min rest between sets), while the left gastrocnemius muscle served as a control. Placebo, allosteric mTOR inhibitor rapamycin, or ATP‐competitive mTOR inhibitor AZD8055 was injected intraperitoneally 1 h before RE. Muscle samples were obtained 1 and 6 h after a bout of RE. RE increased MPS (measured by) at both time points after RE in placebo group. Rapamycin completely inhibited RE‐induced MPS 1 h, but not 6 h, after RE. On the other hand, AZD8055 completely inhibited RE‐induced MPS at both time points after RE. The phosphorylation of p70S6K at Thr389 and 4E‐BP1 at Thr37/46, which are downstream targets of mTORC1, was sensitive to both rapamycin and AZD8055. However, inhibition of 4E‐BP1 phosphorylation was more pronounced by AZD8055. Moreover, only AZD8055 inhibited the phosphorylation of Akt at Ser473, a downstream target of mTORC2. We conclude that RE‐induced increase in MPS is mTOR signaling‐dependent process, and furthermore, both rapamycin‐sensitive and ‐insensitive mTOR signaling regulate this event.

Support or Funding Information

This work was supported by JSPS KAKENHI Grant No. 267028.
Whole Eggs and Egg Whites Ingestion Induce Similar Increases in Muscle Anabolic Signaling Phosphorylation after Resistance Exercise in Trained Young Men
Authors: Sawan Sidney Abou , van Vliet Stephan , Shy Evan L , Beals Joseph W , Paluska Scott A , Burd Nicholas A , Moore Daniel R
Published: November 2023

The effect of nutrient‐dense food ingestion immediately after resistance exercise as a nutritional strategy to promote muscle anabolism has not been clearly established. Given that a coordinated anabolic response is necessary for the regulation of muscle protein synthesis with exercise and protein ingestion, our aim was to determine whether egg whites or whole eggs ingestion influenced post‐exercise mechanistic target of rapamycin complex 1 (mTORC1) and mitogen‐activated protein kinase (MAPK) signaling phosphorylation in human skeletal muscle. In crossover trials, 10 healthy resistance‐trained men (21±1 y; 88±3 kg; bodyfat: 16±1%; means±SD) completed lower body resistance exercise (4 sets of 10 repetitions at 80% of 10‐RM for both leg press and leg extensions) before ingesting whole eggs (18 g protein, 17 g fat) or egg whites (18 g protein, 0 g fat) in scrambled form. Muscle biopsies were obtained before exercise and at 2 and 5H after protein ingestion to assess the phosphorylation of candidate anabolic signaling molecules by Western blotting. The phosphorylation of mTORser2448 increased ~34% above fasted at 5H following whole egg and egg white consumption (time effect; P<0.01) with no difference between conditions (P>0.66). Downstream of mTORC1, 4E‐BP1Thr37/46 was elevated above fasted at 2H (~22–44%; P<0.01) and was sustained above fasted at 5H (P<0.01) with no differences between conditions (P>0.14). There was no effect of food ingestion on S6K1Thr389 and eEF2Thr56. The phosphorylation of the MAPK ERK1/2Thr202/Tyr204 was similarly suppressed at 2 and 5H following feeding for the whole egg and egg white conditions (~430–780%; P<0.001). Ingestion of isonitrogenous amounts of whole egg and egg white similarly stimulates anabolic signaling in young trained males. These findings would suggest a similar increase in mRNA translation initiation during recovery from resistance exercise in healthy young men. Identification of the intracellular localization of mTORC1 and its colocalization with positive (e.g. Rheb) and negative (e.g. TSC2) regulators via immunofluorescence is ongoing.
Deficiency of the intermediate filament syemin causes abnormalities in striated muscle and reduces bone mass
Authors: Garcia‐Pelagio Karla P. , Moorer Megan , Buo Atum , Chen Ling , Stain Joseph , Bloch Robert
Published: November 2023

A large number of diseases ranging from skin disorders, to premature aging, to skeletal and cardiac myopathies are usually associated to mutations in genes encoding intermediate filament (IF) proteins, but synemin presence and function has not been described in skeletal tissue. IFs associate with the contractile machinery and costameres of striated muscle and with intercalated disks in the heart. It also acts as an A‐kinase anchoring protein (AKAP). We study the role of synemin in skeletal and cardiac muscle, and in bone by examining adult mice null for synemin (synm −/−). Our major finding in synm −/− mice are that: 1) Cardiac muscle shows left ventricular remodeling, contractile dysfunction and hypertrophy suggesting a mixed cardiomyopathy. 2) They present a mild skeletal muscle phenotype, a reduction in tension consistent with an increase in sarcolemmal deformability; and the organization of proteins associated with the contractile apparatus and costameres is not significantly altered and, 3) The presence of osteopenia including more than a 2‐fold reduction in trabecular bone and a reduction in cross sectional area. In total, these data suggest an important role for synemin in striated muscle and bone physiology.

Support or Funding Information

Supported partially by APS‐Physiological Genomics Fellowship and UNAM‐PAPIIT (IA209016) to KPGP; NIH to JPS (R01‐AR063631), and RJB (R01 AR 055928); to NIA to AMB (F31‐AR064673)
Anabolic response with higher protein intake is largely achieved through suppression of protein breakdown in older adults
Authors: Kim Il‐Young , Shin Yun‐A , Schutzler Scott , Azhar Gohar , Ferrando Arny A , Wolfe Robert R
Published: November 2023

Our recent metabolic study demonstrated in young healthy adults that whole body net protein accretion was greater with ingestion of a mixed meal containing ~70g vs. ~40g protein, the latter of which has previously been shown to stimulate a near maximal synthetic response in muscle. To test this relationship in aging adults, we determined whole body protein kinetics in eight older adults (69±5y, 83±14kg, 27±10kg/m2) with a crossover design in the fasted state and following ingestion of 35g (moderate protein, or MP) or 70g (higher protein, HP) protein in mixed meals. Whole body protein kinetics [i.e., protein synthesis (PS), breakdown (PB), and net balance (NB)] (mg/kg LBM/min)] were expressed as changes from fasted to fed states. Feeding resulted in positive NB at both levels of protein intake (for all; p<0.0001) but to a greater extent with HP (p<0.0001). NB was increased primarily through a greater reduction in PB (p<0.0001) and to a lesser extent the stimulation of PS (p<0.01). The increase in NB in the MP group was entirely due to a suppression of breakdown, as synthesis was not stimulated above the basal state (p>0.10). Importantly, linear relationship was observed between NB and the amount of protein intake (g/kg LBM) per meal (r = 0.997, p<0.0001). In conclusion, as in the healthy young adults, we found in older adults that the whole body anabolic response increases linearly with increasing amount of dietary protein without showing a sign of plateau, largely through a greater suppression of protein breakdown.

Support or Funding Information

The project was financially supported by Award Number UL1‐TR‐000039 and KL2‐TR‐000063 from the National Center for Advancing Translational Science (NCATS).
Docosahexaenoic Acid (DHA), not Leucine, May Protect HepG2 Cells from Palmitate‐Induced Non‐Alcoholic Fatty Liver Disease
Authors: Baum Jamie I , Carroll Timothy G , Shouse Stephanie A
Published: November 2023

Non‐alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in the United States, affecting 70 million adults and ~3% of young children. NAFLD is characterized by an accumulation of fat in the liver cells that is not caused by alcohol. NAFLD is closely associated with obesity and insulin resistance, which are precursors for development of type 2 diabetes. Recent data suggests that the PPARs (PPARα and PPARγ may be connected to the development and progression of NAFLD, which make them potential biomarkers for treating and diagnosing NAFLD. Currently, there are several approaches to treating NAFLD, including nutrition therapy and specific food recommendations. Diets high in protein, high in the branched‐chain amino acid leucine, and diets high in polyunsaturated fatty acids, such as DHA, have been linked with weight reduction and improved insulin resistance. However, neither has been evaluated as a treatment for NAFLD. Therefore, the objective of this study was to analyze the ability of leucine and DHA to act either synergistically or alone to reduce markers of NAFLD using HepG2 cells treated with palmitate as an in vitro model. HepG2 cells (80% confluent) received one of 6 treatments for 48 hours: control, vector control, 0.75 mM palmitate, 5 mM leucine + palmitate, 0.1 mM DHA + palmitate, or leucine + DHA + palmitate. Lipid deposition and markers of energy metabolism were measured. Data was analyzed using one‐way ANOVA with P < 0.05 indicating significance. There was no effect of leucine on cellular lipid deposition. However, cells treated with DHA had significantly less lipid deposition compared to cells treated with palmitate or palmitate + leucine. Palmitate increased Tfam expression compared to controls, however, there was no further effect of leucine. Palmitate + DHA and palmitate + leucine + DHA significantly increased Tfam expression compared to control, palmitate and palmitate + leucine. Palmitate significantly lowered PGC1a and PPARg expression, however treatment with DHA further decreased PGC1α and PPARγ compared to controls and palmitate, alone. Preliminary data shows no treatment effect on SIRT1 or mTOR phosphorylation. Taken together, these data suggest that DHA, not leucine, has the potential to reduce markers of NAFLD in HepG2 cells.

Support or Funding Information

Arkansas Biosciences Institute. University of Arkansas State Undergraduate Research Fellowship.
Reduced energy expenditure and increased sleep time contribute to development of ovariectomy‐induced obesity in mice fed a high fat diet
Authors: Moak Sydney P. , Browning Jackson R. , Dai Xuemai , Hall John E. , do Carmo Jussara M.
Published: November 2023

Loss of ovarian estrogen is associated with metabolic disorders, including central adiposity and insulin resistance. However, the diet‐dependent and independent mechanisms by which loss of ovarian function increases central adiposity and causes metabolic abnormalities remain unclear. In this study we examined if caloric intake, energy expenditure and sleep time are important contributors to development of ovariectomy‐induce obesity in mice fed a control or high fat diet (45%, HFD). Eleven female mice at 4 weeks were divided into two groups: Sham‐operated (n=4) and ovariectomized (OVX, n=7) groups. Mice were fed a control diet for 9 weeks and shifted to HFD for an additional 9 weeks. Food intake and body weight were measured daily and body composition was measured weekly by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), motor activity (MA), sleeping time and feeding behavior were monitored for 4 consecutive days at week 9 during control diet or HFD. OVX did not alter caloric intake (9.4±0.4 vs. 9.0±1.0 kcal/g/day), body weight (23.7±0.8 vs. 23.1±1.0 g) or body composition, MA (45.7±13 vs. 44.3±15 m/day), sleep time (4.6±0.5 vs. 4.1±0.7 hr/day based on 40 sec criterion) or fasting blood glucose (137±1.0 vs. 135±7 mg/dL), but slightly reduced EE (3.0±0.6 vs. 3.8±0.2 kcal/hr) and VO2 (1.1±0.1 vs. 1.4 vs. 0.2 ml/min) compared to Sham group. After HFD feeding, OXV mice had significantly greater weight gain (8.2±1.0 vs. 4.8±1.2 g, p<0.05), increased fat mass (12.3±1.1 vs. 8.4 ± 1.6 g, p<0.05), increased sleep time (15.4±1.6 vs. 11.4±1.4 hr/day based on 40 sec criterion, p=0.03), but similar caloric intake (12.8±1.0 vs. 14.1±1.4 kcal/g/day), lean mass (18.8±1.1 vs. 18.7±0.5 g), MA (45.4±5.2 vs. 67.6±20 m/day), fasting blood glucose (146±8 vs. 125±8 mg/dL) and reduced EE (3.3±0.4 vs. 5.5±0.2 kcal/hr) and VO2 (1.1±0.01 vs. 1.8±0.05 ml/min) compared to Sham group. These results suggest that OVX does not alter body weight homeostasis in mice fed a normal diet, but when combined with HFD reduces energy expenditure and increases sleep time without altering food intake or fasting glucose levels.

Support or Funding Information

(NHLBI‐PO1HL51971, NIGMS‐ P20GM104357 and U54GM115428)
The Link Between Obesity and the Expression of O‐linked N‐acetylglucosamine Transferase in Ictalurus punctatus
Authors: Abernathy Oaklee Layne , Spainhour Rebekah , Kobayashi Yass
Published: November 2023

The obesity epidemic in the United States is a serious concern that has driven researchers to determine genetic mechanisms that may contribute to its development. Previous studies in mice have shown that O‐linked N‐acetylglucosamine transferase (OGT) may serve as a satiety factor responsible for controlling food intake and body weight. OGT appears to signal “fullness” in the brain, and decreased OGT expression leads to massive weight gain and development of an obese phenotype in mice. In channel catfish, genetic selection toward increased growth often leads to the increased accumulation of fats in the abdomen, suggesting that channel catfish can be used as a model organism to study obesity development in humans. Screening of the catfish genome database yielded four highly homologous OGT transcripts. Primers were designed to discriminate two major transcripts containing a fifty base pair insert from the other two transcripts. The nucleotide sequence of amplicon corresponding to OGT transcripts was highly similar (>80%) to those of other fish. Because OGT expression in channel catfish has not been previously studied, the OGT expression was examined in the cDNA of brain, spleen, trunk kidney, liver, Brockman's body, and muscle tissues of “normal” phenotype catfish using RT‐PCR. OGT expression was detected in all tissues and was expressed at various levels. Currently, we are using RT‐PCR to determine quantities of OGT in the tissues. In future research, we will compare OGT expression in obese phenotype catfish to normal phenotype catfish and determine if OGT expression is decreased in obese catfish.

Support or Funding Information

Supported by the Kansas IDeA Network of Biomedical Research Excellence (P20GM103418)
Piece‐Meal: Food is more filling when cut into pieces
Authors: Tal Aner , Wansink Brian
Published: November 2023

We wished to examine whether cutting food into several pieces led to its being rated as more filling. Satiety is driven by psychological, as well as physiological, factors (Wansink 2007; Redden and Galak 2013). If people think they ate a more substantial meal, they feel fuller (Wansink et al. 2010). Perceived quantity can influence psychological satiety (Redden and Galak 2013; Wansink 2007; Tal and Wansink 2014). Here, we wish to examine whether increasing the number of units in a meal by cutting a bagel into pieces increases reported satiety.

Participants (N = 43) completed the study for credit in a behavioral lab. They were randomly assigned to one of three groups. The study was run in the afternoon. Groups alternated every half hour.

All groups were served a mini‐bagel (approximately 42.5 grams) with cream cheese. One group received the bagel whole. The other two groups received the bagel cut into four pieces. For one of those group, the bagel pieces were kept together. For the other, the pieces were spread apart. Participants were instructed to eat the bagel in its entirety. They then reported on fullness on measures of hunger, fullness, and satiation, all reported on 9‐point likert scales, added up to a summary satiety score. Measures were taken pre and post consumption, allowing calculation of increase/decrease in satiation as our dependent measure.

A follow‐up replication was conducted with a larger sample (N = 72). In the replication study, we examined moderation by liking for bagels, measured on a 9‐point likert scale.

Satiety increased the most for the pieces‐together condition (4.77). Whole bagel participants had the second highest increase in satiety (3.75), while those with the pieces apart reported the lowest increase in satiety (2.18). The effect was significant at a .04: F(2, 41) = 3.26.

In the replication study, the effect of condition was significant at a .02 level: F (2, 64) = 4.21. Those in the 4‐pieces condition reported a higher increase in satiety (3.29) relative to eating the bagel whole (2.63). Once again, bagel cut into four spread pieces led to the lowest increases in satiety (1.72). There was also a marginally significant interaction of liking and condition: F(2, 64) = 3.02, p = .056, with those expressing greater liking displaying weaker effects.

Food is perceived as more filling when divided into several pieces. Spreading the food apart mitigates the effect. This is likely because food volume appears lower when spread out, creating an overall appearance of a smaller serving. This provides evidence that it is the number of units, rather than the filling of the plate (Wadhera et al. 2012), that leads to increased satiety. Cutting food to pieces can help consumers feel fuller with similar amounts of food. Knowledge of this effect can thus help reduce overeating and consequent obesity.
Neonatal Supplemental Oxygen Exposure Promotes the Development of Metabolic Disease in Adult Rats
Authors: Sturgeon Madison , Hoover Michael , Leuhrs Rachel , Vellookunnel Shilpa , Chandrasekar Shreya , Murphy Austin , Bates Melissa
Published: November 2023

Premature infants frequently require supplemental oxygen to sustain life, but little is known about how supplemental oxygen administered during the critical developmental window after birth increases the risk of age‐related disease, including obesity and diabetes. We hypothesized that neonatal rats exposed to supplemental oxygen (OXY) would have impaired glucose tolerance and that they would develop a diabetes phenotype earlier than controls (CON), when offered a high fat diet. We used an established rat model of neonatal oxygen exposure (80% O2 for 8–14 days) and glucose tolerance was evaluated 14 days and 12 months post‐natally. To evaluate glucose tolerance, baseline blood glucose was measured after an overnight fast, followed by an intraperitoneal injection of concentrated glucose. Blood glucose was then measured 15, 30, 60 and 120 minutes post‐injection. In a second experiment, two month old OXY and CON rats were randomly assigned to an animal‐based fat diet (60% of calories from fat), or standard, low fat diet for ten weeks. At the beginning of the study and each subsequent week, glucose tolerance was measured. At 14 days and 12 months, OXY rats had higher blood glucose at 15 and 30 minutes compared to CON rats. OXY rats fed a high fat diet developed frank glucose intolerance after 4 weeks. Ten weeks of high fat diet had minimal effect on glucose tolerance in CON rats. Taken together, these data suggest that supplemental oxygen during the neonatal period may pre‐dispose the premature infant to the development of metabolic disease later in life.

Support or Funding Information

This work has been supported by funding from the University of Iowa's Department of Health and Human Physiology.
mTORC1 is Involved in the Regulation of Bardet‐Biedl Syndrome 1 (BBS1) Gene Expression
Authors: Guo Deng Fu , Bell Balyssa , Reho John J , Rahmouni Kamal
Published: November 2023

The high prevalence of obesity is associated with increased health risks such as cardiovascular disease and diabetes. A combination of genetic and environmental factors such as availability of nutrition‐rich food contributes to the epidemic of obesity. Recent studies from our group have demonstrated the importance of hypothalamic BBS genes and the BBSome for the regulation of energy homeostasis. We hypothesized that regulation of BBS genes in the hypothalamus may be altered in diet‐induced obese mice. To test this, we investigated the expression of different BBS genes in the hypothalamus of mice fed with normal diet (ND) or 60% high fat diet (HFD) for 36 weeks. Expression of Bbs1 gene, but not Bbs2, Bbs4, Bbs5, Bbs6, Bbs7, Bbs8 and Bbs9, was significantly decreased in the hypothalamus of HFD fed mice vs. to mice fed ND, by qRT‐PCR (n=6 each, p<0.05). Additionally, we found that Bbs1 gene expression was significantly down‐regulated in the hypothalamus of mice fasted for 16 hrs compared to non‐fasted mice (n=6 each, p<0.05). To gain mechanistic insights, we used mouse hypothalamic GT1‐7 cells. Interestingly, we found that exposing GT1‐7 cells to nutrients (leucine (10 mM) or glucose (4.5 g/dl)), but not insulin (10 nM) for 16 hrs significantly decreased Bbs1 expression (n=3, p<0.05). Furthermore, intracerebroventricular injection of leucine (4 μg) decreased Bbs1 expression in the hypothalamus (n=3, p=0.053). Inhibition of the nutrient sensor, mTOR complex 1 (mTORC1) with rapamycin (100 nM) restored Bbs1 expression in GT1‐7 cells treated with leucine, implicating the mTORC1 pathway in the regulation of Bbs1 gene expression in GT1‐7 cells. Given that mTORC1 interacts with IKKα/β, we then tested IKK inhibition with BMS 345541 (500 nM). We found that this also restored Bbs1 gene expression in GT1‐7 cells treated with leucine. In contrast, NFkB p65 inhibition (NBP2‐29321, 25 mM) did not alter leucine‐induced down‐regulation of Bbs1 expression in GT1‐7 cells. We conclude that overnutrition‐induced decrease in hypothalamic Bbs1 gene expression may impair the BBSome function leading to the development of obesity.

Support or Funding Information

This project is supported by NIH and AHA grants to K.R.
Protein Tyrosine Phosphatase 1B (PTP1B) Deficiency in Proopiomelanocortin (POMC) Neurons Attenuates Body Weight, Fat Mass and Liver Lipid Accumulation in Mice Fed a High Fat Diet
Authors: Aberdein Nicola , Wang Zhen , do Carmo Jussara M , Fang Taolin , Hall John E
Published: November 2023

Leptin acts on the central nervous system (CNS) to reduce appetite and body weight, improve glucose regulation, and increase energy expenditure and sympathetic nervous system (SNS) activity. Central leptin has also been shown to exert antisteatotic effects on non‐adipose tissues. However, in severe obesity there may be resistance to leptin's anorexic, antidiabetic and antisteatotic effects but sustained effects to increase SNS activity, blood pressure (BP), and heart rate (HR). Our previous studies showed that POMC neurons are important for mediating the BP, HR and glucose effects of leptin but the role of POMC neurons in mediating leptin's effects on liver lipid accumulation remain less well defined. In this study we examined if deleting PTP1B, a negative regulator of leptin signaling, specifically in POMC neurons or in the entire forebrain, would protect mice against the adverse metabolic effects of a high fat diet (HFD). Male and female mice with forebrain (PTP1Bflox/flox/CamK2R5‐Cre) or POMC specific (PTP1Bflox/flox/POMC‐Cre) PTP1B deficiency and littermate controls (PTP1Bfox/flox) were fed a HFD from 6–20 weeks of age. Compared to PTP1Bflox/flox mice, mice with PTP1B deficiency in POMC neurons or in the entire forebrain had reduced body weight gain between 6 and 20 weeks of age when fed a HFD (Δ19.1 ±1.7g vs. Δ13.7±1.1g and Δ15.3±1.4g, respectively), and attenuated increase in fat mass (Δ13.3±1.2g vs. Δ7.3±0.7g and Δ10.2±1.0g, respectively). PTP1B deficiency attenuated food intake in forebrain specific PTP1B deficient mice compared to PTP1Bflox/flox and POMC specific PTP1B deficient mice (2.0±0.1g, 2.7±0.1g and 2.5±0.1 g, respectively). Glucose tolerance, expressed as area under the curve (AUC), was improved by PTP1B deficiency in forebrain and POMC specific neurons compared to PTP1Bflox/flox mice fed a HFD (AUC 19016±1172, 23207±1534 and 27561±3088, respectively). Liver fat mass, assessed by EchoMRI at 29±0.5 weeks of age, was reduced and liver lean mass was increased in mice with PTP1B deficiency in POMC neurons or in the entire forebrain (Fat: 8.8±1.8 and 6.0±3.3 mg/g, Lean: 93.6±2.8 and 97.2±5.6 mg/g, respectively) compared to PTP1Bflox/flox mice (Fat: 14.2±2., Lean: 79.4±10.3 mg/g), indicating a healthier liver profile. These findings indicate that PTP1B signaling in POMC neurons plays an important role in regulating body weight, fat mass, glucose tolerance and liver lipid accumulation in response to a chronic HFD but effects of PTP1B on food intake are mediated mainly in forebrain neurons other than POMC.

Support or Funding Information

supported by NHLBI‐PO1HL51971 and NIGMS P20GM104357.
The Effects of Glutamate on Oxytocin Release
Authors: Badmus Yetunde Awwah , Cantley Richard , Hill Jennifer W
Published: November 2023

During pregnancy, weight gain creates a positive energy balance that serves the biological purpose of providing adequate energy stores for the upcoming extended period of lactation. However, excess adiposity is associated with a delay in the initiation of lactation and a reduced duration of breastfeeding. Glutamatergic neurons in the paraventricular nucleus (PVN) are implicated in the control of oxytocin release. Recent studies have also shown that glutamatergic target neurons in this nucleus mediate much of the ability of melanocortins to suppress feeding. Based on novel preliminary data, we hypothesize that glutamatergic neurons of the PVN influence prenatal and postnatal hyperphagia and modify the activity of oxytocin neurons involved in lactation. To test this hypothesis, we have created vglut2/sim1‐cre female mouse, in which the gene for the vesicular glutamate transporter VGLUT2 has been deleted in the PVN. To examine dysfunctional lactation in this model we evaluated multiple parameters including neonatal survival and growth, and analysis of mammary tissue and ovary tissue. In addition, circulating oxytocin, prolactin, and other hormone levels were measured. The number of pups born to homozygous vglut2/sim1 dams that survive until weaning was dramatically down compared to controls; 0% survival was observed when fostering did not occur compared to approximately 100% survival when fostering did occur. Results to date suggest that homozygous vglut2/sim1 mice show a consistent and complete deficit in milk release and a buildup of milk protein and lipids within the mammary glands. In addition, we have observed a potential subfertility phenotype observed in the vglut2/sim1 females. These results highlight a potential pathway whereby obesity and lactational deficiency may develop concurrently. Additional studies will be needed to test whether the glutamatergic neuronal populations in the PVN controlling body weight and lactation overlap.

Support or Funding Information

Supported by a Michigan Diabetes Research and Training Center Pilot & Feasibility Study Grant (P30DK092926:5556) to JWH.
Short‐term high‐fat diet induces sympathoexcitation and increases blood pressure in Wistar rats
Authors: Garcia Michelle L , Nishi Erika E , Oliveira Tales L , Sato Alex Y Simões , Oyama Lila M , Campos Ruy R , Bergamaschi Cassia T
Published: November 2023

The present study aimed to investigate the effects of short‐term high‐fat diet (HFD) on blood pressure and sympathetic vasomotor nerve activity. Furthermore, the influence of white adipose tissue (WAT) innervation on HFD‐induced cardiovascular changes was assessed. Male Wistar rats (250–300g) were divided into 3 independent groups that were treated for 8 weeks with a control diet (CT) or High‐fat diet (HFD) and HFD + WAT denervation (HFD+DNX). At the end of the sixth week of treatment a bilateral retroperitoneal WAT (rWAT) depot denervation was performed in the HFD+DNX group. After this period the mean arterial pressure (MAP), heart rate (HR), renal sympathetic nerve activity (rSNA) and splanchnic sympathetic nerve activity (sSNA) were recorded directly. HFD animals presented a significant slightly increase in MAP (109± 1; n=7 vs 101± 1 mm Hg; n=7 p<0.05) and a greatly increase in sSNA (82±10; n= 5 vs 46±10 spikes/s; n=5, p< 0.05) compared with CT group. Bilateral rWAT denervation reduced MAP (104±7 mmHg; n=7) and sSNA (57±9 spikes/s, n=5). No changes were observed in baseline HR and rSNA among groups. The present study suggests that short‐term HFD induces preferential sympathoexcitation to splanchnic territory and increases in blood pressure. Whether afferents and/or efferents from WAT participate in these responses remains to be elucidated.

Support or Funding Information

CAPES and Cnpq
Leptin Induces the Expression of the Leptin Receptor in the Hypothalamic Paraventricular Nucleus
Authors: Pelletier Nicole E. , Shi Zhigang , Levasseur Peter R. , Marks Daniel L. , Brooks Virginia L.
Published: November 2023

We recently reported that nanoinjection of leptin into the hypothalamic paraventricular nucleus (PVN) elicits a slowly developing increase in sympathetic nerve activity (SNA), despite a well‐documented paucity of leptin receptors (LepR). This result suggests that leptin may induce the expression of its own receptor. To test this hypothesis, male SD rats (n=4) were anesthetized with α‐chloralose and were instrumented with electrodes for recordings of lumbar SNA (LSNA) and with femoral catheters for infusions and recordings of mean arterial pressure (MAP) and heart rate (HR). After collecting baseline data, leptin (60 ng in 60 nL) was injected into one side of the PVN, and the artificial cerebrospinal fluid (aCSF; 60 nL) vehicle was injected into the other side. Measurements of LSNA, MAP, and HR were continued for the following 6 hr. The animals were then deeply anesthetized, and brains were collected, flash frozen, sectioned (20 μm), and stored for subsequent in situ hybridization (ISH) assay of the LepR in PVN using antisense 33P‐labeled LepR (corresponding to bases 10–407 of rat LepR). Levels of LepR in each side of the PVN were assessed in three sections by counting the total number of silver grains using custom‐designed software that subtracts background signal from selected regions. Unilateral injections of leptin into the PVN increased LSNA to 136±18 % control, MAP from 123±9 to 134±4 mmHg, and HR from 350±22 to 392±28 bpm (all P<0.05). LepR ISH revealed LepR signal on both sides of the PVN; however, the total number of silver grains was greater in the leptin‐treated side (2628±204) compared to the aCSF‐treated side (1996±47) (P<0.05). In conclusion, leptin induces the expression of its own receptor in the PVN.

Support or Funding Information

NIH HL128181, AHA 12GRNT11550018 and 15POST23040042.
Transient receptor potential vanilloid type 1 (TRPV1) activation in the Nucleus of the Solitary tract inhibits brown adipose tissue sympathetic nerve activity
Authors: Madden Christopher J
Published: November 2023

Stimulation of vagal afferent fibers or activation of neurons in the NTS (the site of vagal afferent terminals) inhibits sympathetic outflow to BAT. TRPV1 which is densely expressed in visceral vagal afferents can be directly activated by endogenous lipids to increase visceral afferent activation of neurons in the NTS. The current study investigated whether activation of TRPV1 receptors in the NTS inhibits BAT SNA and compared the level of endogenous activation of TRPV1 in rats maintained on a control chow diet or a high fat diet. In urethane/chloralose anesthetized rats maintained on a control chow diet, nanoinjection of the highly potent and selective TRPV1 receptor agonist resiniferatoxin (RTX) completely inhibited cold‐evoked BAT SNA. In rats on a control chow diet blockade of TRPV‐1 receptors in the NTS by pretreatment with the TRPV1 antagonist capsazepine (CPZ) had no effect on basal or cold‐evoked BAT SNA but prevented the RTX evoked inhibition of BAT SNA. In contrast, in rats maintained on a high fat diet for at least 8 weeks BAT SNA failed to increase during cold exposure. Nanoinjection of CPZ in the NTS reversed the HFD‐induced impairment of cooling‐evoked BAT SNA. These data demonstrate that activation of TRPV1 receptors in the NTS inhibits cold‐evoked increases in BAT SNA and suggest that in rats maintained on a high fat diet there is an elevated endogenous activation of the TRPV1 receptors in the NTS that is necessary for the high fat diet‐induced impairment of BAT activation.

Support or Funding Information

Supported by American Diabetes Association Basic Science grant #1‐13‐BS‐120.
Sphingolipid chaperone proteins modulate signal transduction and pathophysiology
Authors: Hla Timothy
Published: November 2023

Although originally thought as an intracellular second messenger, work over the past two decades have shown that sphingosine 1‐phosphate (S1P) acts primarily as an extracellular lipid mediator. Our laboratory cloned the first S1P receptor as an orphan G protein‐coupled receptor (GPCR) from vascular endothelial cells in 1990 and de‐orphaned in 1998. Some of the well‐studied actions of S1P include its essential roles in vascular development, immune cell trafficking and neuronal development. Inhibition of GPCR‐dependent S1P signaling results in therapeutic efficacy in the autoimmune disease of remitting, relapsing multiple sclerosis (RRMS). We recently discovered that the majority (~65%) of plasma S1P is chaperoned by HDL‐bound Apolipoprotein M. Plasma S1P is essential for lymphocyte trafficking. This talk will discuss the role of chaperone‐dependent signaling of HDL‐bound Apolipoprotein M. Our recent studies suggest that HDL‐bound S1P acts as a biased agonist to suppress vascular inflammation and restore endothelial function. In the immune system, HDL‐bound S1P is dispensable for immune cell trafficking but suppresses lymphopoiesis and neuroinflammation in mouse models. In the liver, ApoM‐bound S1P is critical for liver regeneration and suppression of fibrosis. Better understanding of fundamental biochemical principles involved in S1P signaling may aid in the development of novel therapeutic principles in vascular and immunological diseases.

Support or Funding Information

The work was supported by grants from the NIH and the Fondation Leducq transatlantic network program.
Tonic Glycinergic Inhibition of brown adipose tissue (BAT) Sympathetic Premotor Neurons in Rostral Raphe Pallidus (rRPa)
Authors: Conceicao Ellen Santos
Published: November 2023

The rRPa contains BAT sympathetic premotor neurons controlling BAT sympathetic nerve activity (SNA) and BAT thermogenesis. We report here the contribution of a tonic activation of glycineA receptors in the rRPa at the inhibitory regulation of BAT SNA and BAT thermogenesis, as well as cardiovascular parameters, in urethane/chloralose anesthetized, artificially‐ventilated rats. Under warm conditions, nanoinjection of strychnine (STR) into the rRPa increased BAT SNA (peak: +495% of control), BAT temperature (TBAT, + 1.1 °C), expired CO2, (+ 0.4 %), core body temperature (TCORE, + 0.2 °C), mean arterial pressure (MAP, + 4 mmHg) and heart rate (HR, + 57 bpm). Glycine (GLY) injection into the rRPa evoked a potent, 74 % inhibition of cooling‐evoked BAT SNA, and reductions in TBAT (−0.2 °C), TCORE (−0.2 °C), expired CO2 (−0.2 %), MAP (−8 mmHg), and HR (−22 bpm), but did not reduce any of these parameters after STR nanoinjection into rRPa. Nanoinjection of STR into the rRPa had no effect on the ability of nanoinjection of GABA into the rRPa to inhibit BAT SNA (−86 % of the cold‐evoked BAT SNA), and expired CO2 (−0.4 %). Blockade of glutamate receptors with AP5/CNQX into rRPa markedly inhibited the STR‐evoked increases in BAT SNA (−56 %), TBAT (−0.4 °C), expired CO2 (−0.8 %), MAP (−8 mmHg) and HR (−34 bpm). Regarding the synaptic integration occurring at the BAT sympathetic premotor neurons in the rRPa, we conclude that a tonically‐active, glycinergic inhibitory input contributes to reductions in their discharge probabilities that compete with their excitatory inputs from the DMH and brainstem sites to determine the level of BAT thermogenesis and energy expenditure.

Support or Funding Information

This work was supported by NIH R01‐NS091066 (S.F.M.).
Lactic acid bacteria isolated from Korean kimchi modulate the vitamin D receptor‐autophagy signaling pathways
Authors: Shang Mei , Zhang Yong‐Guo , Lu Rong , Jiao Yang , Xia Yinglin , Kim Cheol‐Hyun , Kang Sang‐Moo , Sun Jun
Published: November 2023

Purpose

Vitamin D receptor (VDR) plays an essential role in pathogenesis of various human diseases, including inflammatory bowel disease (IBD). Our recent study (Wang, et al, Nature Genetics, 2016) has demonstrated that human VDR is a key host factor to shape gut microbiome. Further, our study has demonstrated that intestinal epithelial VDR conditional knockout (VDRΔIEC) leads to dysbiosis. Low expressions of VDR is associated with impaired autophagy, accompanied by a reduction of ATG16L1 and LC3B (Wu, et al, Gut, 2015). Patients with IBD usually present low expression of VDR and an impaired vitamin D status. Probiotics have been used in the anti‐inflammation process of IBD. The purpose of this study is to investigate the potential effects and mechanism of probiotics in modulating the VDR‐autophagy pathways.

Methods

We tested five probiotics Lactobacillus strains (Lactobacillus plantarum PS128, Lactobacillus plantarum DK119, Lactobacillus acidophilus La5, Lactobacillus 109 and Lactobacillus reuteri 121), which were isolated from Korean Kimchi. Conditional medium (CM) was used to treat human intestinal epithelial HCT116 cells and measured the expression of VDR. Expressions of autophagy markers LC3B and regulator Beclin1 were evaluated by Western blot. Mouse embryonic fibroblast (MEF) cells with or without VDR were also used to test the change of the VDR signaling and VDR dependence of the autophagy signaling. To test the role of probiotics in anti‐inflammation, HCT116 and Caco‐2 cells were treated with 121‐ CM prior to infection with Salmonella Enteritidis. In vivo, the role of probiotic in regulating VDR‐autophagy‐apoptosis signaling was tested, using 121‐CM orally administrating to VDRloxp and VDRΔIEC mice.

Findings

Probiotics‐treated groups showed higher mRNA expression of the VDR and its target genes cathelicidin, compared to the control group, In addition, probiotic treatment could enhance beclin 1 and change the ratio of LC3B 1 and 2, indicating the activation of autophagy. Furthermore, 121‐CM treatment prior to Salmonella infection dramatically inhibited the apoptosis and inactivated NF‐kB pathway. Administration of 121CM to VDRloxp and VDRΔIEC mice for 12 and 24 hours resulted in an increase of VDR, p62 and Beclin1 expression and a decrease of Bcl‐2, Bax, phospho‐IkBα, and TLR4 expression.

Implications

We highlight the beneficial effects of these five probiotics in upregulating VDR signaling and autophagic responses and suppressing inflammation. Furthermore, these effects are associated with the VDR‐autophagy pathway. Our data indicate novel therapeutic and beneficial roles of probiotics Lactobacillus strains, isolated from Korean Kimchi, in inhibiting inflammation and infection.

Support or Funding Information

This work was supported by the NIDDK1R01DK105118‐01 to Jun Sun. Mei Shang was partially supported by International Program for Ph.D. Candidates, Sun Yat‐Sen University