bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation by Astrocytes of AMPA Currents in the NTS Neurons of Mice Is Reduced by Short Term-Sustained Hypoxia
Authors: Accorsi-Mendonça Daniela , Lima-Silveira Ludmila , Machado Benedito H
Published: May 2024

Hypoxia due to reduction in the partial pressure of oxygen in the arterial blood (PaO2) activates the afferents of peripheral chemoreflex to produce cardiovascular and respiratory adjustments to bring PaO2 back to the normal range. Herein we evaluated the possible changes of astrocytic modulation on glutamatergic transmission in NTS neurons of mice submitted to short term-sustained hypoxia (SH). To reach this goal, we used Male C57Bl/6J mice (18-20g), which were submitted to SH (FiO2 0.1) or normoxia for 24 hours. Brainstem slices and whole-cell patch clamp technique were used to evaluate the synaptic transmission in NTS neurons. The intracellular calcium concentration in NTS astrocytes was evaluated by multiphoton microscopy and transgenic Aldh-CRE-GCAMP6f mice (Institutional Ethical Committee Approvals: #016/2018 and #1109/2022R1). SH increased the amplitude of TS-evoked AMPA currents [control: -72.8 ± 13.3 pA ( n = 12) vs SH: -120 ± 14.4 pA ( n = 21)] in NTS neurons with no changes on the rise- or decay-time. SH also increased the amplitude [control: 35.88 ± 7.9 pA ( n = 12) vs SH: 72.74 ± 15.47 pA ( n = 10)] and decay time [control: 61.8 ± 15.2 ms ( n = 9) vs SH: 286 ± 86.7 ms ( n = 10)] of TS evoked-NMDA currents in neurons, while the amplitude of extrasynaptic NMDA currents [control: 28.7 ± 7.4 pA ( n = 10) vs SH: 24.7 ± 3.2 pA ( n = 7)] was not affected. Perfusion with fluoracetate (FAC), a glial metabolism inhibitor, decreased the amplitude of TS-evoked AMPA currents in control group [aCSF: -54.29 ± 16.1 pA vs aCSF + FAC: -24.43 ± 6.82 pA ( n =9)] without affecting AMPA currents in SH neurons [aCSF: -124.5 ± 35.27 pA vs aCSF + FAC: -130.5 ± 50.16 pA ( n =8)]. The passive properties of astrocytes did not change after SH [RMP: -83.73 ± 11.85 mV ( n =10) vs −83.63 ± 11.86 mV ( n =10); Rinput: 123 ± 127.5 MΩ ( n =9) vs 208 ± 212.7 MΩ ( n =10)]. The increase in intracellular calcium concentration induced by AMPA in the astrocytes of control and SH mice was similar [Control: 112.8 ± 15.41 ΔF/F0 (n=68 ROIs) vs SH: 56.38 ± 18.31 ΔF/F0 (n=13 ROIs)]. The data shows that SH increased the evoked glutamatergic currents in NTS neurons of mice, probably due to a reduction in the astrocytic modulation of excitatory transmission by mechanisms apparently independent of astrocytic intracellular calcium.

FAPESP (2018/15957-2, 2018/02336-0 and 2022/05237-8), CNPq (309338/2020-4) and CAPES-PROEX (23038.006922/2021-31).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Impaired excitability of nucleus tractus solitarius neurons in a neonatal rat model of hyperbilirubinemia
Authors: Mayer Catherine , Rickman Nicholas , Bearer Cynthia , MacFarlane Peter
Published: May 2024

Hyperbilirubinemia is associated with multiple morbidities including apnea of prematurity in preterm infants. Bilirubin, a byproduct of hemoglobin breakdown, is not excreted normally and results in high circulating levels giving rise to a state of hyperbilirubinemia. Free bilirubin (not bound to albumin) can cross the blood-brain barrier and be neurotoxic. Prior studies have shown that a systemic injection of bilirubin accumulates in the brainstem and is associated with an impaired ventilatory response to hypercapnia and an augmented hypoxic ventilatory depression. Here, using the Gunn rat model of endogenous hyperbilirubinemia, we investigated its effects on the excitability of neurons of the nucleus tractus solitarius (NTS). The homozygous Gunn rat (jj) model of hyperbilirubinemia lacks uridine diphosphate-glucuronosyltransferase-1A1, an enzyme which is needed to catabolize bilirubin. Heterozygous Nj Gunn rat pups were used for control. On postnatal (P) day 5, Nj and jj rat pups received either a 200mg/kg intraperitoneal injection of sulfadimethoxine (SDMX), which dissociates bilirubin from albumin resulting in increased levels of circulating free bilirubin, or an equivalent amount of saline as a vehicle control. Whole cell patch clamp was performed on NTS neurons two days later (P7) to assess characteristics of evoked excitatory postsynaptic currents (eEPSC).The amplitude of the evoked stimulus response to a 20Hz stimulus train was significantly increased in NTS neurons from jj+saline pups when compared to cells from Nj+saline and Nj+SDMX animals (p<0.05). This increased amplitude was no longer present after SDMX treatment of jj pups. Additionally, jj+saline NTS neurons did not exhibit any failure to solitary tract stimulation, whereas SDMX treatment significantly increased the failure rate during a 20Hz stimulus train (jj+saline =0.0%±0.0, jj+SDMX= 18.63%±8.82, p<0.05). Comparison of failure rate of jj+saline to Nj+saline (6.63%±3.12, p<0.05) was also statistically significant. The hyper-responsive NTS neurons of jj+saline rats may be an adaptive response to the deleterious effects of circulating (bound and unbound) bilirubin. However, the impaired response of neurons in jj+SDMX rats may reflect neurotoxic effects of increased free bilirubin leading to impaired neurotransmission. The latter is consistent with the high failure rate of NTS neurons in jj+SDMX rats. These data may have implications for impaired respiratory control mechanisms involved in mediating essential vagally mediated ventilatory defense responses to hypoxemia and may contribute to the apnea of prematurity associated with hyperbilirubinemia in preterm infants.

William and Lois Briggs Endowment.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Enteral Agonism of the Farnesoid X Receptor-Fibroblast Growth Factor 19 Axis Prevents Cholestasis in TPN-Fed Piglets
Authors: Elefson Sarah , Vonderho Caitlin , Melendez Hebeib Valeria , Stoll Barbara , Mohammad Mahmoud , Chacko Shaji , Guthrie Gregory
Published: May 2024

Total parenteral nutrition (TPN) administration provides necessary nutrients to infants who cannot tolerate enteral feedings. However, the use of TPN can result in cholestasis which can cause parenteral nutrition-associated liver diseases. Previous mitigation strategies for cholestasis have included administering bile acids enterally to encourage normal bile acid metabolism. The objective of this study was to determine if treatment of either ursodeoxycholic acid (UDCA), Tropifexor (TPX), or fibroblast growth factor 19 (FGF19) will prevent cholestasis in a piglet TPN model through the activation of the farnesoid X receptor (FXR)-FGF19 axis. We hypothesize that UDCA will have minimum effects on FXR while TPX, a potent FXR agonist, will significantly affect the FXR pathway, and FGF19 will reduce bile acid synthesis to alleviate cholestasis. Piglets received TPN for 3 weeks and were treated enterally with either UDCA (25 mg/kg*day) or TPX (7.5 μg/kg*day) with minimal milk-based formula (12 mL/kg*day), or daily intravenous FGF19 (0.25 mg/d) injection. Body weight gain was not different after 3 weeks. Plasma markers of cholestasis such as of total bile acids, bilirubin, and gamma-glutamyl transferase were lower in pigs that received TPX compared to the control treatment at the end of the study. Circulating levels of FGF19 and tissue concentrations of total bile acids were not different across treatments. In the ileum, TPX increased mRNA expression of FGF19, ileal lipid binding protein, and organic solute transporter α compared to the control pigs. All treatments reduced the mRNA expression of apical sodium-dependent bile acid transporter compared to the control treatment. TPX also increased mRNA expression of small heterodimer protein and bile salt export pump in the liver. Overall, we conclude that UDCA and FGF19 had minimal effects on cholestasis, whereas TPX prevented cholestasis in part via activation of the FXR-FGF19 axis in TPN fed piglets.

NIDDK R01-DK094616 K01 DK129408 T32 NIH grant DK07664.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Salivary biomarkers as assessment of metabolic function and inflammation in children with obesity
Authors: Kemp Keri , Orihuela Catheryn , Evans Retta , Mrug Sylvie
Published: May 2024

Childhood obesity increases adult metabolic and cardiovascular disease risk. Using blood for long-term biomarker analysis in children is problematic because of the discomfort, pain, and anxiety associated with frequent blood draws. Noninvasive methods are vital for predicting childhood obesity complications. This study examined body mass index-for-age percentile scores (zBMI) as a predictor of salivary biomarkers of metabolism and inflammation, including insulin and C-Reactive Protein (CRP), over time. A school sample of 288 adolescents (Mage = 12.1 at study initiation; 46% female; 48% Black, 37% non-Hispanic White, 15% Hispanic or other minorities) were enrolled from greater Birmingham, Alabama. Participants provided salivary samples across four days once per year from 2019–2021. In year 1 of the study, 19% of adolescents were overweight, 18% had obesity, 6.6% had severe obesity, and 7.3% had very severe obesity based on the 2022 CDC Extended BMI-for-Age Growth Charts. Multivariable models showed that lower parental income was associated with an increased risk of obesity (OR = 0.91; 95% CI = 0.85, 0.97; p = 0.009). Greater concentrated poverty, a measure of spatial distribution of socioeconomic deprivation, was associated with an increased risk of severe or very severe obesity (OR = 1.58; 95% CI = 1.01, 2.46; p = 0.043). However, race/ethnicity was not associated with obesity risk. Longitudinal analyses showed that greater zBMI in year 1 was associated with greater salivary CRP ( β = 0.188, SE = 0.058, p = 0.001) and insulin ( β = 0.263, SE = 0.076, p<0.001) in years 2 and 3 of the study after adjusting for year 1 biomarker levels, sex, race/ethnicity, and concentrated poverty. Multivariable models indicated that an accelerated increase in zBMI/year was associated with an accelerated increase in CRP/year ( β = 0.119, SE = 0.048, p = 0.014), but there was no association between the rates of change in zBMI and insulin. Future analyses will incorporate additional hormones, such as adiponectin, and inflammatory cytokines measured in saliva. In conclusion, these results indicate that salivary biomarkers can capture physiological differences associated with zBMI in school-age children. Saliva may constitute a useful non-invasive tool for evaluating markers of inflammation and/or metabolism related to zBMI in children outside clinical settings.

This research was supported by an Institute of Education Sciences, U.S. Department of Education Grant (R305A180074) to SM and RE and a National Heart, Lung, and Blood Institute K99R00 Grant (1K99HL165091-01A1) to KMK.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Ad Libitum Drinking Prevents Body Mass Loss Across Consecutive Workdays in Heat
Authors: Rawlings Alexander , Kozlin Michael , Przybysz Johnathan , Cavuoto Lora , Schlader Zachary , Pryor Riana
Published: May 2024

Hydration practices across consecutive days of heavy-intensity work in heat when fluid is freely available is unknown. Without this information it remains unknown whether hydration modifies heat strain under hot working conditions and whether worker recommendations adequately maintain hydration status. We hypothesized that participants would maintain hydration status including daily percent change in body mass across workdays. Fifteen healthy, unacclimated participants (7 Females, Age: 27±6 y, Body mass: 75.0±14.4 kg, Body fat: 26.6±5.8%) completed three consecutive days (Day 1, Day 2, Day 3) of 4 h of 395±10 W work to a work/rest cycle of 45/15 min in a 36.3±0.8°C, 21±5% relative humidity environment. Participants were offered 237 mL of a sport drink every 20 min to consume ad libitum. Urine flow rate (UFR) was measured before work. Urine specific gravity (USG) and nude body mass were measured before and after work. Thirst and fluid consumption were measured throughout work. USG before work was not different between Day 1 (1.013±0.010) and Day 2 (1.013±0.010, p=0.822), but was greater before work on Day 3 (1.015±0.010, p=0.046) compared to Day 2. Change in USG from before to after work was not different between Day 1 (+0.003±0.008) and Day 2 (+0.000±0.006, p=0.123), but was lower on Day 3 (-0.002±0.006, p=0.021) compared to Day 1, with no difference between Day 2 and Day 3 (p=0.058). Before work body mass was not different across days (p=0.103). Daily percent change in body mass was not different across days (p=0.366, Day 1: 0.53±1.11%, Day 2: 0.18±0.95%, Day 3: 0.18±0.81%), indicating weight gain each day. Sweat rate (p=0.790) and UFR (p=0.469) were not different among days. Participants consumed 77±18% (Day 1), 82±19% (Day 2), and 82±16% (Day 3) of fluid offered (p=0.401), equaling 31±10 mL/kg (Day 1), 33±11 mL/kg (Day 2), 33±10 mL/kg (Day 3) (p=0.370). Maximum thirst was greater on Day 1 (3.5±1.1) compared to Day 3 (2.9±1.0, p=0.045) with no difference between Day 1 and Day 2 (3.4±1.4, p=0.648) or between Day 2 and Day 3 (p=0.121). This study demonstrates consistent hydration practices and no differences in hydration status across three consecutive days of high-intensity work in heat when fluid is freely available. Under these conditions, workers can consume fluids ad libitum and worker recommendations for hydration during heat stress should be revisited.

This project was funded my the National Institute for Occupational Safety and Health (1K01OH012016-01A1).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Homeostatic regulation of circuit activity through temperature-sensing rather than activity-sensing
Authors: Cannon Delaney , Santin Joseph
Published: May 2024

Electrical signaling between nerve cells coordinates essential functions of the body. However, neurons face their own regulatory challenges, as they need to produce relatively constant activity patterns as the environment changes. Like homeostatic control that occurs within other organ systems, neural circuits are subject to homeostatic regulation as well, whereby deviations from a set point level of activity elicit corrective responses to maintain circuit output. To achieve this end, neural systems are thought to sense variables that relate to neuronal activity, such as firing rate, ion concentrations, and neuromodulators, to detect when an imbalance in activity occurs. While recording rhythmic motor activity associated with breathing in the American bullfrog, we made the surprising observation that acute cooling to 10°C silenced network activity, but after several minutes, bursting resumed and then overshot baseline frequency upon rewarming. Burst frequency drifted back to the initial value over tens of minutes, consistent with the fast regulation of an activity set point (n=9). Time controls with no temperature changes were stable throughout this period (n=7). Exposing the network to manipulations inducing similar perturbations that silence activity over the same timescale– hypoxia (n=6), glycine (n=6), and tetrodotoxin (n=4)– did not engage feedback regulation. These results suggested that temperature sensing, rather than activity sensing, controls network output. Cation channels activated by cooling in amphibians (TRPM8, n=4; TRPV3, n=4) and L-type Ca2+ channels (n=4) did not contribute to these responses. Experimental activation of the Na+/K+ pump with monensin, which raises intracellular Na+, reduced the compensation response both in the cold (p=0.01, unpaired t-test) and in the overshoot phase following warming, suggesting that cold-dependent inhibition of the Na+/K+ pump enhances network excitability. Finally, NMDA-glutamate receptors played a role in constraining the amount of compensation, as block of NMDARs with D-APV led to compensation that greatly exceeded those observed in the control experiments (n=5, p<0.0001, unpaired t-test), remaining elevated above baseline upon rewarming in all experiments. The cellular mechanisms by which raising intracellular Na+ with monensin and NMDAR signaling influence compensation responses are ongoing. Overall, these results uncover a temperature-sensitive control system that regulates activity in neural circuits. Our results introduce that some neural systems may replace typical activity sensors with regulatory systems that are instead tuned to environmental cues to defend activity set points.

R01NS114514, R15NS112920-01A1.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
β-catenin Signaling Drives Intestinal Epithelial Production of Interleukin-33
Authors: Schumacher Michael , Thai Megan , Liu Cambrian , Frey Mark
Published: May 2024

Background: Interleukin (IL)-33 is a key responder to intestinal infection, injury, and inflammation. It drives protective epithelial re-modeling via a stromal-epithelial circuit. However, we know little about the regulation of epithelial IL-33 at homeostasis and in disease. Our group previously found that colonic epithelial production of IL-33 is restrained by the inflammation-responsive signaling regulator, Sprouty2. Loss of Sprouty2 activates GSK3β (a key mediator of canonical Wnt/β-catenin signaling) and induces IL-33 in the colon, but the specific role of β-catenin and Wnt pathway components involved in this induction are unknown. Hypothesis: Canonical Wnt/β-catenin signaling induces colonic epithelial expression of IL-33. Methods: Bulk and single-cell RNAseq were performed on colons from mice with an intestinal epithelial-specific Sprouty2 deletion (Spry2IEKO) or littermate controls and subjected to gene enrichment and Panther pathway analyses. Colonic epithelial cell cultures were treated with Wnt3a and R-spondin to activate β-catenin signaling; small molecule inhibitors were used to inhibit CBP- or p300-mediated β-catenin signaling arms. IL-33 levels were assayed by qPCR and ELISA. Results: Analysis of significantly altered genes in Spry2IEKO colons by Panther analysis found an enrichment in genes regulated by canonical Wnt signaling (FDR 3.72E-02), correlating with increased IL-33 observed in these mice. Analysis of single-cell RNAseq suggests colonic epithelial IL-33 is predominantly expressed in the stem and progenitor cell niche. Colonic epithelial cells treated with Wnt ligand showed a significant induction in IL-33 (p<0.05) at both RNA and protein levels. Inhibition of CBP-mediated but not p300-mediated β-catenin signaling prevented IL-33 induction, correlating with decreased expression of the CBP inhibitor, Psen1, in Spry2IEKO colons. Conclusion: CBP-mediated β-catenin signaling promotes colonic epithelial expression of IL-33. Acute inflammation-mediated loss of Sprouty2 drives IL-33 induction in the stem cell niche as a protective response to injury or infection.

NIH K01DK131390 (MS); Crohn's and Colitis Foundation CDA (MS); NIH R01DK135954 (CL); NIH R01DK119694 (MF).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Mitochondrial NAD Profile in a Rat Model of Attention-Deficit/Hyperactivity Disorder
Authors: Schwarzer Hannalyn , Brandauer Josef
Published: May 2024

Mitochondria require nicotinamide adenine dinucleotide (NAD) to satisfy cellular energy needs. Mitochondrial stress has been reported in skeletal muscle tissue of humans with attention-deficit/hyperactivity disorder. NAD deficiency may indicate mitochondrial stress that can be assessed through NAD concentration assays and Western blotting of Nampt and Sirtuin 3 (SIRT3) proteins. Nampt is the rate-limiting enzyme in intracellular NAD recycling, while SIRT3 is an NAD-dependent protein deacetylase that regulates mitochondrial mass and activity. The objective of this study was to investigate skeletal muscle and liver tissues of rat strains that exhibit behaviors associated with ADHD. We hypothesized that tissues from rat models with ADHD-like behavior (Lewis and F344 strains) would have lower NAD concentrations and reduced Nampt and SIRT3 protein expression relative to the control strain (Sprague Dawley). To examine this hypothesis, we performed fluorescence tissue NAD concentration assays. We found a significant difference in liver NAD between Sprague Dawley and F344 rats (Sprague Dawley, 0.14 ± 0.07 mM/mg [mean ± standard deviation], F344, 0.22 ± 0.11; p < 0.05). Western blot analysis for Nampt and SIRT3 proteins revealed a significant difference between the F344 and Sprague Dawley rats for Nampt protein in the extensor digitorum longus (EDL) muscle (Sprague Dawley, 1043930 ± 303677 arbitrary units [AU], F344, 1729014 ± 553568 AU; p < 0.05). Our results indicate minor differences in tissue NAD concentration and Nampt protein expression in rat models with ADHD-like behaviors. This could be indicative of differential mitochondrial function in skeletal muscle or liver tissues. Further studies will examine the implications of increasing nicotinamide riboside in the skeletal muscles to observe the effects of NAD functioning.

This work was supported by funds provided by the Cross-Disciplinary Science Institute at Gettysburg College (X-SIG) (HMS, JB) and a Gettysburg College Professional Development Grant (JB).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Exploring the synergistic potential of probiotics and vitamin D to ameliorate acute TNBS-induced colitis in mice
Authors: Lopez Jonathan , Ramos-Plaza Vivianka , Rodriguez-Morales Bryan M. , Cruz Myrella L. , Appleyard Caroline B.
Published: May 2024

Inflammatory Bowel Disease (IBD), either Crohn’s disease or Ulcerative Colitis, are diseases characterized by chronic inflammation of the gastrointestinal tract, disruption of mucosal barrier, gut dysbiosis and vitamin D deficiency. The use of probiotics or vitamin D supplements have been studied individually in different colitis models to determine their beneficial effects by increasing tight junction proteins such as occludin. However, the synergistic effects of combining these treatments to target tight junction expression are still unknown. Therefore, the objective of this research was to demonstrate the effcacy of probiotics and high dietary vitamin D to ameliorate colonic inflammation by increasing mucosal barrier integrity. We hypothesized that co-administration of a probiotic mixture with vitamin D would reduce colitis-induced inflammation by increasing tight junction expression. For the methodology, male and female C57BL/6 mice were divided into four treatment groups: Colitis+Vehicle (n=10), Colitis+Probiotic (n=10), Colitis+Vitamin D (n=11), Colitis+Probiotic+Vitamin D (n=7). Animals received seven days of pretreatment with Vivomixx probiotics in water, high vitamin D (5IU/g) in food, or both. On day 7, animals were anesthetized lightly, and colitis induction was done by intracolonic administration of 0.1mL of 4mg TNBS in 30% ethanol. Water, food, and body weight were monitored daily. Animals were sacrificed on day ten, the colonic tissue was removed and assessed for inflammation then stained for occludin expression by immunofluorescence, and probiotic colonization was confirmed within fecal samples by RT-PCR amplification of S. Thermophilus gene. Results indicate that all animals decreased weight after colitis induction, but only animals receiving probiotic had a slight recovery by day 10. Animals receiving the probiotic mixture had higher S. Thermophilus expression in fecal samples compared to vehicle (p<0.001) indicating appropriate colonization. A significant reduction in macroscopic damage score (3.92 vs. 7.42, p<0.05) and microscopic score (3.42 vs 7.20, p<0.01) was found in animals with Probiotic+Vitamin D compared to vehicle. Although an increase in occludin expression was observed with probiotic administration it did not reach statistical significance. In conclusion, findings indicate a beneficial effect of combining probiotics and vitamin D on colonic tissue damage in an animal model of acute colitis but this did not impact the tight junction protein occludin.

This work was supported by RISE (R25GM082406), G-RISE (T32GM144896), PRI MD Summer Program and Porter Physiology Development Fellowship.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Lack of Renal NHE1 Exacerbates Lithium-Induced Nephrogenic Diabetes Insipidus
Authors: Blanco Gabriella , Thomas Linto , Dominguez Rieg Jessica Ann , Rieg Timo
Published: May 2024

The sodium-hydrogen exchanger isoform 1 (NHE1) is a transporter with roles in transepithelial Na+/H+ transport, intracellular pH (pHi), and cell volume regulation. Within the kidney, we localized NHE1 to the basolateral membrane of the distal parts of the nephron and collecting duct (co-labelling with AQP2 for principal cells and H+-ATPase B1 subunit for all 3 types of intercalated cells: type A, B, and non-A-non-B). We have previously shown that lack of NHE3 does not affect Li+ clearance, and other studies have shown that NHE1 transports Li+ preferably compared to NHE3. Therefore we hypothesized that NHE1 plays a critical role in Li+-induced nephrogenic diabetes insipidus. To address this question, we used newly generated mice which lack NHE1 protein in the tubule/collecting duct system (NHE1KS-KO) of the kidney. After baseline measurements, control (n=12) and NHE1KS-KO (n=9) mice were switched to a Li+-containing diet (0.2% LiCl [40 mmol/kg], Harlan Teklad, TD09326) for 4 weeks. Urine osmolality was not different between groups under baseline conditions (control: 2641±178, NHE1KS-KO: 2716±244 mmol/kg). In response to Li+, urine osmolality reached a minimum after 7 days that was sustained until the end of the experimental period. Of note, urine osmolality was ~500 mmol/kg lower in NHE1KS-KO versus control mice (1125±170 versus 475±94 mmol/kg, P<0.05) despite genotypes having comparable plasma Li+ concentrations (0.48±0.1 versus 0.45±0.1 mmol/L). Plasma Na+ concentrations were not significantly different under baseline conditions (149±0.5 versus 148±0.4 mmol/L) but increased to a significantly greater extent in NHE1KS-KO versus control mice (156±1.9 versus 152±0.5 mmol/L, P<0.05). Along those lines, plasma Cl− was significantly greater in NHE1KS-KO versus control mice at the end of the experimental period (117±1.9 versus 111±0.4 mmol/L, P<0.05). Taken together, our data indicate that NHE1 in principal cells plays an important role in the development of nephrogenic diabetes insipidus as well as the development of hypernatremia and hyperchloremia.

This work was supported by a VA Merit Review Award IBX004968A (to Dr. Rieg) and a Pilot Project from the USF Microbiomes Institute (to T.R. and J.D.R).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Caki-1 Spheroids as a 3D Model for Studying Free Fatty Acid-Induced Proximal Tubule Lipotoxicity
Authors: Battle Dana , Qiu Xiangzhe , Alex Marilyn , Rivers London , Zhao Xueying
Published: May 2024

Three-dimensional (3D) multicellular spheroid shows a biological complexity resembling native tissue in comparison to conventional monolayer cultures, making it a better model system to assess drug effcacy and cytotoxicity. The main aim of this study was to examine the usefulness of Caki-1, a human proximal tubule (PT) representative cell line, as a 3D model system for studying free fatty acid-induced PT lipotoxicity. Caki-1 spheroids were generated and maintained on ultra-low attachment plates and characterized regarding time-dependent changes in morphology and functionality. In optimal 3D culture conditions, Caki-1 cells formed well-defined large compact 3D spheroids with uniform morphology, good circularity, and increased diameter from days 2-10. There was no change when the spheroids were incubated with lipid-free bovine serum albumin (BSA, 0.5%) from day 6 to 10. Chronic exposure to palmitate (300 μM) resulted in dispersed and flattened spheroid morphology, with a larger number of dead cells in the peripheral layers and decreased spheroid core. Moreover, palmitate-treated spheroids showed a significant increase in caspase-3 activity at the external layers of the spheroids, suggesting that the detached cells underwent apoptosis. Simultaneous addition of oleate (200 μM) prevents palmitate-induced spheroid disintegration and cell death in Caki-1 3D culture. Mechanistically, palmitate triggered endoplasmic reticulum (ER) stress and autophagy dysfunction, as evidenced by significantly increased protein levels of ER stress markers AFT4 and CHOP, and autophagy substrate p62. Oleate upregulated adipose differentiation-related protein (ADRP, a lipid droplet-associated protein), and promoted lipid droplet formation in palmitate-treated Caki-1 cells. These results indicate that Caki-1 3D spheroids are a simple and reproducible in vitro system for lipotoxicity study. It can potentially be used for evaluating human renal proximal tubular toxicity and drug screening.

NIH/NIGMS R16GM149499, NIH TL1DK136047.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The use of micro-computed tomography to investigate splenic control of resting oxygen consumption in Tenrec ecaudatus
Authors: Smith Gilbecca Rae , Silva Rubio Claudia , van Breukelen Frank
Published: May 2024

The canonical functions of the spleen e.g. immune function, blood filtering, and iron recycling overshadow its known role as a blood storage organ in mammals. Boreoeutherians or modern mammals, such as race horses and dogs, experience splenic contractions during exercise where a 30-40% increase in red blood cell availability is associated with an increase in oxygen consumption. Early data (pre-1960) suggest that splenic sequestration may be used in hibernators. Tenrec ecaudatus are basoendothermic mammals that possess numerous ancestral features such as a cloaca. We posit that tenrecs may provide evolutionary insight into the ancestral function of the spleen. Tenrecs may experience as much as a 25-fold variation in resting oxygen consumption as well as a 14-fold variation in spleen size. We contend that sequestration of red blood cells to the spleen in tenrecs controls oxygen consumption. Here, we present data that directly tests the association of spleen size and oxygen consumption using micro-computed tomography. We contend the boreoeutherian functions of the spleen may be a derived condition afforded by a heightened level of endothermy/homeothermy and its associated higher level of homeostasis.

National Science Foundation, Department of Education.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Plasma circulating extracellular vesicles indicate dysregulation of synaptic vesicle-associated signaling pathways in SHIV-infected rhesus macaque
Authors: Chandra Partha , Panner Selvam Manesh Kumar , Braun Stephen , Castorena-Gonzalez Jorge , Rutkai Ibolya , Sikka Suresh , Busija David
Published: May 2024

Background: Recent studies point out the involvement of circulating extracellular vesicles (crEVs), in regulating neurotransmission via transferring proteins, lipids, and nucleic acids. Recently, we reported that plasma crEV proteins of either simian human immunodeficiency virus (SHIV) infected rhesus macaque or HIV-infected patient indicate a link to neuropathogenesis. Here, we tested the hypothesis that crEV proteins are indicative of dysfunction of synaptic vesicle (SV)-associated signaling pathways of SHIV-infected rhesus macaques. Methods: Plasma crEVs were isolated from SHIV-infected (SHIV-crEVs) and uninfected (CTL-crEVs) rhesus macaque and characterized by the ZetaView analyzer. Proteomic analysis of the isolated crEVs was performed using liquid chromatography/mass spectrometry (LC-MS/MS). Results: Our ZetaView analysis indicated that isolated crEVs were predominantly exosomes (particle size < 150 nm). In the LC-MS/MS study, 5,654 proteins were quantified, with 236 proteins (~ 4%) significantly differentially expressed between SHIV-crEVs and CTL-crEVs. Several SV and SV-signaling pathway associated proteins were quantified by tandem mass tags-based proteomic analysis both in SHIV-crEVs and CTL-crEVs. We observed that synaptogyrin, synaptotagmins, synaptobrevin, synaptosomal-associated proteins, syntaxin, and other SV-associated proteins were abundantly under expressed in SHIV-crEVs than in CTL-crEVs. Ingenuity Pathway Analysis demonstrated that proteins in SHIV-crEVs were involved in the deactivation of synaptogenesis, synaptic long-term protentiation/depression, and glutamate receptor signaling pathways. On the other hand, semaphorin neuronal repulsive signaling pathway and amyloid processing were activated in SHIV-crEVs. Bioinformatic analysis revealed that these proteins in SHIV-crEVs were involved in several CNS-related disorders/diseases such as abnormal morphology of synapses, motor dysfunction and movement disorder, seizure disorder, early/progressive neurological disorder, cognitive impairment, tauopathy, dementia, and Alzheimer’s disease. Conclusions: Our novel findings suggest that plasma crEVs could be an attractive noninvasive technique, which may elucidate the development of neuronal dysfunction and progression of neurological diseases.

Funding: AG075988, HL148836, AG063345, AI110158, HL141143, HL168568, and the Louisiana Board of Regents Endowed Chairs for Eminent Scholars program.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The laterodorsal tegmental nucleus improves breathing and sleep in a Parkinson’s disease animal model
Authors: Miranda Nicole , Oliveira Luiz , Moreira Thiago , Kalume Franck , Ramirez Jan Marino , Takakura Ana
Published: May 2024

Parkinson's disease (PD) is a neurological disorder resulting from the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). PD is characterized by classical and non-classical symptoms including respiratory instability and sleep disturbances. An important region for the control of sleep and possibly respiration is the laterodorsal tegmental nucleus (LDTg), a nucleus composed of cholinergic, glutamatergic, and GABAergic neurons. We hypothesize that stimulation of cholinergic neurons in the LDTg can lead to improvements in sleep and respiratory disturbances in a murine model of PD. Adult mice (CEUA: 6641200919 and SCRI: 18819) that express the fluorescent green protein in cholinergic cells (Chat-cre, ai6) received bilateral injections of AAV-hM3Dq-mCherry or AAV-mCherry vectors into LDTg. After ten days, the animals received nigrostriatal injections of vehicle or 6-hydroxydopamine (6-OHDA, 10 μg/μl). Eight days later, we implanted EEG and EMG electrodes. In 6-OHDA-injected mice, there was a 79% and 29% reduction in the number of dopaminergic neurons in SNpc and cholinergic neurons in LDTg, respectively. This reduction was associated with an increase in the number of apneas and a 17% and 26% reduction in respiratory frequency during non-REM (NREMs) and REM (REMs) sleep, respectively. In the same animals, there was also a decrease in wakefulness time, and an increase in total sleep time. Selective pharmacogenetic stimulation of ChAT+ neurons of the LDTg rescued the respiratory frequency during REMs and reduced the number of apneas both in NREMs and REMs in 6-OHDA mice. These results demonstrate that in this PD model the LDTg plays a significant role in respiratory changes associated with sleep regulation.

FAPESP, CAPES, CNPq and NIH.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Knowledge and Testing of Hepatitis B Virus Infection and Vaccination Awareness among University Students in Kumasi, Ghana: A Cross-Sectional Study
Authors: Abban Elizabeth , Owusu Emmanuel , Kwakye-Abebrese Benedicta , Koduah Bright , Boateng Hannah , Korsah Emmanuel Ekow , Effah Alfred , Akpobi Solomon , Avoh-Ackah Emmanuel , Senu Ebenezer
Published: May 2024

Background. Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV) and major global health problem, affecting millions of people globally. Whilst college or university students could serve as a positive vehicle that may aid in the propagation of education in the communities, there is currently paucity of data on knowledge of HBV and vaccination awareness among university students in Ghana. This study therefore assessed knowledge on hepatitis B virus infection, testing, and vaccination awareness among science and non-science students in Ghana. Method. This cross-sectional study included 386 students from the Garden City University College, Kumasi, Ghana, from February to June 2022. A well-structured questionnaire was used to obtain data on knowledge, testing, HBV vaccination status, and sociodemographic characteristics of participants. All statistical analyses were done using SPSS Version 26.0 and GraphPad prism version 8.0. A Chi-square test statistic and logistics regression analyses were used to determine factors associated with study variables among study participants. p value of <0.05 and 95% confidence interval were considered statistically significant. Results. About half (51.5%) of the participants had adequate knowledge on hepatitis B infection with 22.3% demonstrating poor knowledge on hepatitis B infection. A little more than average (51.6%) previously tested for hepatitis B (HBV) whilst 32.9% were highly aware of hepatitis B vaccination and 33.9% were not aware of hepatitis B vaccination. This study found that ethnicity of students (p=0.0020), family history of hepatitis B infection (p=0.0160), and academic cumulative weighted average (CWA) (p=0.0020) were significantly associated with knowledge about hepatitis B infection. Also, students reading science-related programs had more than twice the odds (aOR = 2.56, 95% CI (1.03–5.08), p=0.0210) of having tested for HBV infections before compared to students who read non-science programs. Furthermore, sex (p<0.0001), family history of HBV vaccination (p=0.0260), CWA (p=0.0060), and the program of students (p=0.0020) were significantly associated with awareness of HBV vaccination. Conclusion. Knowledge of HBV infection among university students is satisfactory but awareness of HBV vaccination and testing is poor. There is a need to enhance educational interventions to improve the general knowledge of HBV infection, testing, and vaccination in Ghana especially among non-science students.
Dietary Threonine Promoted the Growth and Ovarian Development of the Red Swamp Crayfish (Procambarus clarkii)
Authors: Yao Haihang , Cao Manxia , Zhang Jianmin , Xie Shouqi , Luo Kai , Xiao Wenfu , Dong Lixue , Gao Weihua , Tian Juan
Published: May 2024

To explore the effects of dietary threonine on growth and ovarian development of red swamp crayfish (Procambarus clarkii), crayfish (5.48 ± 0.19 g) were fed six isoproteic and isoenergetic diets with varying levels of threonine (7.16 g/kg (control), 9.19, 12.74, 16.44, 20.83, and 23.78 g/kg) for 8 weeks. The results showed that weight gain rate, feed conversion ratio, protein efficiency rate, protein deposition rate, and essential amino acid deposition rates obtained the optimal values when the dietary threonine level was 12.74 or 16.44 g/kg. Compared to the control group, the 12.74 g/kg group exhibited enhanced nonspecific immunity and antioxidant properties. The 16.44 g/kg group demonstrated a significant increase in the frequency of B cells and R cells in the hepatopancreas, the length and width of intestinal villi, and the activities of protease and lipase. It also showed elevated ecdysterone hormone, gonadal index (GI), cAMP content, and the relative abundance of beneficial intestinal microflora. Compared to the control group, the mRNA expression of mTOR, S6K1, 4EBP1, EcR, RXR, chitinase, PKA, Vg, cdc2, and cyclin B was significantly upregulated, and the mRNA expression of MIH was significantly downregulated in the 16.44 g/kg group. Overall, optimal dietary threonine could improve intestinal health, regulate immune function, and enhance protein utilization, molting, and growth performance of red swamp crayfish. Additionally, it improved the synthesis of yolk substance and facilitated the development of ovarian cells of female crayfish. The optimal threonine level was 14.87–16.94 g/kg (dry matter), corresponding to 42.51–48.42 g/kg of dietary protein in red swamp crayfish.
Modelling Land Surface Temperature Variation in New Guinea Island from 2000 to 2019 Using a Cubic Spline Model
Authors: Munawar Munawar , McNeil Rhysa , Prasetya Tofan Agung Eka , Jani Rohana , McNeil Don , Pongsiri Nitinun
Published: May 2024

Land surface temperature (LST) is a critical indicator variable in climate science. In this study, the variation of LST on the island of New Guinea during 2000 to 2019 was investigated using a cubic spline model and a multivariate regression model. The data were obtained from the National Aeronautics and Space Administration moderate resolution imaging spectroradiometer database. This study focused on 90 subregions with 105-pixels of latitude 90 kilometer apart. These subregions were categorized into 10 super-regions. The results showed that the mean change in LST for all 90 subregions was +0.086°C per decade with a confidence interval of (0.028, 0.144)oC. There were five super-regions with a significant mean LST change. LST increased significantly in the central-north, central-south of the island (super-regions B1, C1, and C2 with 0.117°C, 0.162°C, and 0.185°C, respectively) and the southern part of Papua New Guinea (super-region E2 with 0.217°C), whereas it decreased in the middle part of the Indonesian territories (A2 with −0.122°C). The results also showed that LST variation occurs at the subregional level. Climate change mitigation methods are critical for reducing temperature rise and limiting any negative effects on the region.
Determination of the Appropriate Blended Inorganic Fertilizer Rate Recommendation for the Optimal Common Bean (Phaseolus vulgaris L.) Grain Yield and Profitability in the Dawuro Zone, Ethiopia
Authors: Daemo Berhanu Bilate , Wolancho Getahun Bore , Wakalto Dawit Dalga
Published: May 2024

Soil fertility decline is a significant factor affecting crop production. In a specific area, fertilizer application for a crop depends on soil type and profitability. Moreover, optimizing chemical fertilizer utilization in crop production is crucial from both environmental and economic perspectives. However, there is limited information available on the optimum NPSB fertilizer rate for common bean production in the study area. Thus, the study aimed to establish area-specific NPSB fertilizer rate recommendations for optimal grain yield and profitability of common bean. The field experiment was conducted in two locations in the 2019 and 2020 cropping seasons. The treatments included 0, 25, 50, 75, 100, 125, 150, 175, and 200 kg·ha−1 NPSB fertilizer rates, and they were planted using a randomized complete block design with three replications. The combined location analysis of variance indicated that the application of NPSB fertilizer significantly influenced plant height, number of pods per plant, number of seeds per pod, hundred-seed weight, biomass yield, grain yield, and harvest index. The highest grain yields (2815 kg·ha−1 and 3433 kg·ha−1) were recorded with the application of a 125 kg·ha−1 NPSB blended fertilizer rate, while the lowest grain yields (1429 kg·ha−1 and 1500 kg·ha−1) were produced from the nonfertilizer applied plot in Deneba and Wara, respectively. The combined location mean showed that the maximum grain yield (3124 kg·ha−1), followed by 2710 kg·ha−1, was produced by the application of 125 and 100 kg·ha−1 NPSB fertilizer rates, respectively. The data indicate that raising the NPSB fertilizer rate from 0 to 125 kg·ha−1 would greatly boost grain yield in the common bean in both locations in a similar manner. The economic analysis revealed that applying 125 kg·ha−1 of NPSB fertilizer earned the highest net benefits (140453.2 ETB·ha−1) with the highest marginal rate of return (1745.26%). Therefore, for high yield and profitability of common bean, a rate of 125 kg·ha−1 NPSB fertilizer is suggested in the study area and similar agro-ecological zones.
Supplementary table 3 from A Phase II Study of ERK Inhibition by Ulixertinib (BVD-523) in Metastatic Uveal Melanoma
Authors: Buchbinder Elizabeth I. , Cohen Justine V. , Tarantino Giuseppe , Lian Christine G. , Liu David , Haq Rizwan , Hodi F. Stephen , Lawrence Donald P. , Giobbie-Hurder Anita , Knoerzer Deborah , Sullivan Ryan J.
Published: May 2024

Supplementary table 3: Adverse Events/toxicities felt to be at least possibly related to drug.
FIGURE 1 from A Phase II Study of ERK Inhibition by Ulixertinib (BVD-523) in Metastatic Uveal Melanoma
Authors: Buchbinder Elizabeth I. , Cohen Justine V. , Tarantino Giuseppe , Lian Christine G. , Liu David , Haq Rizwan , Hodi F. Stephen , Lawrence Donald P. , Giobbie-Hurder Anita , Knoerzer Deborah , Sullivan Ryan J.
Published: May 2024

Waterfall plot: depiction of percent tumor change among evaluable patients.