bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel cystine transporter in renal proximal tubule identified as a “missing partner” of cystinuria‐related membrane protein rBAT/SLC3A1
Authors: Nagamori Shushi , Wiriyasermkul Pattama , Nakagomi Saya , Okuyama Hirohisa , Okuda Suguru , Ohgaki Ryuichi Ohgaki , Kanai Yoshikatsu 
Published: November 2023

Heteromeric amino acid transporter (HAT) family is one of the major amino acid transporter families responsible for cellular uptake and epithelial transport. HATs form heterodimers composed of a 12 membrane spanning light chain (SLC7) that catalyzes transport functions and a single membrane spanning heavy chain (SLC3) essential for plasma membrane localization and stabilization of the light chains. Among HAT family, the heterodimer of b0,+AT/SLC7A9 and its auxiliary subunit rBAT/SLC3A1 is responsible for cystine reabsorption in renal proximal tubules. The mutations in either subunits cause cystinuria, an inherited aminoaciduria with impaired renal reabsorption of cystine and dibasic amino acids. However, an unsolved paradox is that rBAT is highly expressed in S3 segment, the late proximal tubules, whereas b0,+AT expression is the highest in S1 segment, the early proximal tubules. Therefore, the presence of unknown partner of rBAT in S3 segment has been proposed. In this study, by means of co‐immunoprecipitation followed by mass spectrometry, we have found that AGT1/SLC7A13 is the missing partner of rBAT. AGT1 is localized in the apical membrane of S3 segment, where it forms a heterodimer with rBAT. Proteoliposomes reconstituted purified AGT1‐rBAT heterodimer transported cystine, aspartate and glutamate. In the apical membrane of the S3 segment, AGT1 is suggested to locate itself in close proximity to sodium‐dependent acidic amino acid transporter EAAC1 for efficient functional coupling. EAAC1 is proposed to take up aspartate and glutamate released into luminal fluid by AGT1 due to its countertransport so that preventing the urinary loss of aspartate and glutamate. Taken all together, AGT1 is the long‐postulated second cystine transporter in S3 segment of proximal tubules and a candidate to be involved in isolated cystinuria.Support or Funding InformationThis work was supported in part by Grants‐in‐Aid for Scientific Research on Priority Areas of “Transportsome” (to Y.K.) and Innovative Areas “HD Physiology” (to S. Nagamori) from the Ministry of Education, Culture, Sports, Science and Technology of Japan; Grants‐in‐Aid for Scientific Research (to Y.K. and S. Nagamori) from the Japan Society for the Promotion of Science.
Tricyclic antidepressants as inhibitors of the multidrug transporter, human OCT2: Influence of structural similarity to inhibitory efficacy
Authors: Terpstra Jennifer , Wright Stephen H 
Published: November 2023

Organic cation transporter 2 (OCT2) mediates the initial step in renal secretion of organic cations, which comprise approximately 40% of currently prescribed drugs. Due to its potential as a target for unwanted drug‐drug interactions (DDIs), much attention has been directed toward understanding the basis of OCT2 selectivity. These studies typically assess selectivity based on inhibition profiles for OCT2‐mediated transport of a probe substrate produced by a structurally diverse range of test inhibitors. Here we assessed the profile of OCT2 inhibition produced by 9 structurally similar inhibitors, i.e., a set of tricyclic antidepressants (TCAs). Structural similarity was assessed by Tanimoto coefficients, which ranged from 0.5 to 0.83. As the measure of transport activity we determined uptake of a fluorescent substrate, N,N,N‐trimethyl‐2‐[methyl(7‐nitrobenzo[c][l,2,5]oxadiazol‐4‐yl)amino]ethanaminium iodide (NBD‐MTMA) into cells stably expressing OCT2. Uptake was effectively linear for 5 min, and the Jmax and apparent Kt values for NBD‐MTMA were 25 ± 5.2 pmol cm−2 min−1, and 11.7 ± 5.7 μM, respectively. Despite the structural similarity of the test inhibitors, IC50 values varied by up to 100 fold, from as low as 0.2 ± 0.02 to 0.4 ± 0.03 μM (Amitriptyline and Doxepin), to 2.1 ± 0.07 to 3.1 ± 0.05 μM (for Imipramine and Protriptyline), to as large as 20.2 ± 4.14 to 27.7 ± 1.8 μM (for Chlorpromazine and Butriptyline). There was no correlation between degree of similarity (based on Tanimoto coefficients) and pairwise comparison of IC50 values for all the TCAs tested. The comparatively high affinity of OCT2 for Amitriptyline and Doxepin, combined with reported unbound Cmax levels, resulted in Cmaxub/IC50 ratios that exceed 0.1, highlighting them as potential perpetrators of unwanted DDIs. These data show that similarity of structure is not a good criterion for predicting inhibitory interaction with OCT2.Support or Funding InformationNIH grant 5R01DK58251
The Effect of Maternal Separation and Early Environmental Enrichment on the Rat Colon
Authors: Colón‐Echevarría Claudia , Cruz Myrella L , Doreste Raura , Torres‐Reveron Annelyn , Appleyard Caroline B 
Published: November 2023

BackgroundEarly life stress has been associated with increasing the risk of developing gastrointestinal disorders by disrupting the brain‐gut axis function. Maternal separation (MS) in rats is a well‐studied model of early life stress and has been linked to inflammation in adulthood in conditions such as inflammatory bowel disease and irritable bowel syndrome. Environmental enrichment (EE) has been hypothesized to prevent the damaging effects of stress exposure by stabilizing the hypothalamic‐pituitary‐adrenal axis but there is no timeframe yet established to pinpoint when this treatment is more effective.AimInvestigate whether maternal separation causes intestinal inflammation and whether early environmental enrichment can reverse any alterations.MethodsSprague‐Dawley rat pups (both male and female, n=4–6/treatment group/gender) were separated from the mother for 3 hours/day from postnatal day one until 21 days of age. Rats were kept in either standard housing or environmental enrichment boxes, until postnatal day 78 when forced swim and open field‐testing were performed before sacrifice. Colon tissues were removed and paraffin embedded, after which microscopic scoring, crypt length and mast cell counts were evaluated.ResultsMS caused an increase in microscopic colon damage compared to normal controls (not exposed to MS or EE) in both females (p<0.05) and males (p<0.001). MS animals also had longer crypt length and increased mast cells. Males showed greater damage than female rats after MS protocol and EE, however enriched males showed a decrease in depressive‐like behaviors while enrichment did not have any effect in females. The early environmental enrichment did not reverse the damage caused in maternally separated rats but tended to decrease mast cell infiltration.ConclusionMS caused inflammation in the colonic tissue, which was not attenuated by early EE. Damage to the mucosal barrier by MS may be due to loss of tight junction proteins. Future studies need to be performed to evaluate the effect of later environmental enrichment on MS rats.Support or Funding InformationSupported in part by R25GM082406, K07AT008027, and MD007579.
Changes in Gastric Myoelectrical Activity in Response to Selected Cranial Osteopathic Manipulations in Healthy Young Individuals
Authors: Ioudina Marina , Toder Eric , Samra Parneet , Kaldawi Sami 
Published: November 2023

Osteopathic manipulations in the cranial field (cranial manipulation, CM) are a part of osteopathic manipulative treatment and are commonly used to treat patients. It is suggested that CM affects the autonomic nervous system. We hypothesized that CM may have an effect on the digestive system and have conducted this study to measure gastric electrical activity in response to selected CM using non‐invasive cutaneous electrogastrography (EGG). Healthy 25–35 year old men and women participated in this study. All CM were performed by one osteopathic physician and data were recorded and analyzed using BIOPAC Systems, Inc. equipment and software. CM effectiveness was evaluated based on the changes in the amplitude of the EGG in the frequency range that is associated with gastric slow waves.Our preliminary results indicate that CM appears to decrease the amplitude of the EGG. These data suggest that selected cranial manipulations may affect gastric motility.Support or Funding InformationThis project was funded by the TUN Research Grant Award.
PERFORMANCE IN GROSS ANATOMY AND IDENTIFICATION OF STUDENTS NEEDING ASSISTANCE/GUIDANCE IN LEARNING
Authors: Zill Sasha 
Published: November 2023

GoalThe goal of this study is to improve teaching of Gross Anatomy to first year medical students and enhance performance on Step 1 Board Examinations by utilizing questions on Anatomy written examinations as a metric for early identification of students needing assistance/guidance in learning.MethodsThe data base was derived from tests given to first year medical students as part of training in a required course in Gross Anatomy. Multiple choice questions (written by the investigator) were part of written examinations given in different body regions. The specific questions were in the areas of: General Introduction to the Nervous System; Anatomy of the Lower Extremity; Anatomy of Head and Neck. Student scores on specific questions were analyzed from records kept by investigator. Data on class performance in subsequent Step 1 Board Examinations were derived from reports generated by our school.ResultsComparison of the mean scores on written examinations in Gross Anatomy showed no clear relationship with subsequent performance of the classes on Step 1 National Board Examinations. However, there was a significant correlation between the number of students having difficulty with Gross Anatomy and subsequent board exam performance (P = <0.0001, Student's T test).DiscussionThe results to date indicate that performance on questions in Gross Anatomy examinations may be a useful metric in identifying students that may require assistance in learning body structure and medical terminology. The lack of correlation of overall performance in Gross Anatomy and Board exams could readily reflect the decrease in the number questions that directly test anatomical knowledge. However, it is important note that the mean performance of classes on the Gross Anatomy examinations was quite high and the many questions were asked repeatedly with no attempt to make them more discriminative. The specific causes of difficulties encountered by some students are unclear but may reflect their academic background and extent of training in Anatomy prior to entrance into medical school. Overall, these results suggest that analysis of questions in Gross Anatomy may be of considerable utility in early identification students and remediation of students that have difficulty in the basic core of knowledge and language of medicine.
Skeletal Muscle PPARδ Increases Acutely with Resistance Exercise Inversely Proportional to Body Fat Percentage
Authors: Chen Vincent CW , Lee Chang Woock , Bui Steve , Lee Teak V , Riechman Steven E 
Published: November 2023

PurposePPARδ expression in skeletal muscle has been shown to increase in response to resistance exercise training in our laboratory. However, it is unclear whether PPARδ expression is affected by a single bout of resistance exercise. Since dyslipidemia is associated with excess body fat, we examined the relationship between the change of PPARδ content and percent body fat in response to one bout of whole body resistance exercise.MethodsEleven untrained young men (N=4) and women (N=7) performed one bout of whole body resistance exercise that included leg press and leg extension for emphasis on quadriceps femoris muscles. Body fat percentage was measured by DEXA before exercise. Muscle biopsies were performed on the vastus lateralis muscles 24 hours before and 24 hours after the exercise. Western Blotting was conducted to quantify the PPARδ content.ResultsWith body fat percentage as a covariate, PPARδ levels increased by 49.1% (p<0.001) after one bout of resistance exercise. The amount of changes in PPARδ was inversely proportional to the body fat percentage (R2=0.769, P=0.001).ConclusionOur data suggest that when adjusted for body fat percentage, resistance exercise may acutely increase PPARδ content, which may be a key factor of lipid metabolism.Support or Funding Information1. The Sydney & J.L. Huffines Institute for Sports Medicine & Human Performance 2. American College of Sports Medicine‐ Texas Chapter (TACSM) 3. Department of Health and Kinesiology, Texas A&M University 4. College of Education and Human Development, Texas A&M University
Age Dependent Changes in Muscle Expression of Enzymes Effecting The Production of Testosterone and Dihydrotestosterone in Young and Old Mice and the C2C12 Cell Line
Authors: Pearson Tim , Powell Penny 
Published: November 2023

BackgroundSarcopenia is a debilitating condition that exhibits a progressive decline in skeletal muscle mass and function with age. Sarcopenia can lead to an increased susceptibility to falls and can result in the loss of independent living. Despite this, the causes and mechanism(s) underlying sarcopenia are not fully understood.MethodsYoung (3 month) and aged (>22 month) male mouse extensor digitorum longus (edl; a fast‐twitch muscle), soleus (a slow‐twitch muscle), and anterior tibialis muscle bundles were rapidly isolated and subsequently prepared for use in western blotting. The expression of enzymes influencing testosterone (T) and dihydrotestosterone (DHT) production were investigated in the different age groups, with similar protein targets being investigated in C2C12 myoblast and myotube cells after treatments with either DHT (5nM) or T (30nM).ResultsOverall, all muscles investigated showed more pronounced expression of 5α‐reductase‐2 than that of 5α‐reductase‐1, both of which generate DHT from T, irrespective of age. Both reductases were more abundant in aged muscles, irrespective of muscle type except that of the anterior tibialis for reductase‐2 which was reduced with age. We report androgen receptor expression in myoblasts that increased significantly with exposure to DHT or T, whereas the expression of the androgen receptor in myotubes was only weakly detectable. In response to the DHT or T treatments, myoblast expression of; aromatase, 5α‐reductase‐1/2, 17‐β‐hydroxysteroid dehydrogenase, Myo‐D, Pax7 and the amino acid transporters SNAT2 and LAT2 were unchanged. Interestingly myotubes showed increased expression upon exposure to DHT or T of Myo‐D and trends to increased expression of 5α‐reductase‐2 and SNAT2 with no change in Pax7, aromatase, 17‐β‐hydroxysteroid dehydrogenase or LAT2.ConclusionFrom these results we suggest that a component of sarcopenia may arise from an age‐dependent reduction of the DHT or T dependant anabolic stimulus. We also suggest that muscles such as the soleus and edl attempt to resist this reduction in androgens by locally generating DHT by enhancing expression of 5α‐reductase enzymes. A possible mechanism of action to DHT exposure may involve active satellite cells and the increased expression of SNAT2 to then modify amino acid transport into muscle, where both of these may influence positively muscle viability.Support or Funding InformationFunded by the BBSRC.
Measuring Damaged Area is More Reliable than Counting Damaged Myofibers in Cross Sections of Injured Skeletal Muscle
Authors: Abro Valerie M , Begam Morium , Roche Joseph A 
Published: November 2023

BACKGROUNDHistological studies of dystrophic and/or injured skeletal muscle, often involve quantifying the extent of myofiber damage. Our laboratory's current standard operating procedure is to count damaged and intact fibers in a cross section, and express myofiber damage as (Damaged Fibers/Total Fibers) X 100. However, it can be difficult to estimate the number of fibers in a region where myofiber boundaries have been obliterated due to extensive tissue damage. We therefore compared the inter‐rater reliability between an expert and a novice, for quantifying myofiber damage, based on counting damaged myofibers or measuring damaged area. We hypothesized that measuring damaged area has a higher inter‐rater reliability than counting damaged myofibers.METHODSFive unique digital images (Zeiss Axio Scope.A1 LED FL‐LED microscope, 20X objective) were analyzed by a novice (2 weeks of experience) and an expert (13 years of experience) with Image J software. Images were of cross sections of injured mdx mouse skeletal muscle, stained with fluorescently‐labeled antibodies to mouse IgG, since IgG entry is a marker of myofiber damage. Counts of IgG‐positive (IgG+) fibers and measurements of IgG+ areas were compared for intra‐rater reliability, and data from each method were compared between novice and expert for inter‐rater reliability.RESULTSThe Pearson's Correlation Coefficients (R scores) for intra‐rater reliability between IgG+ fibers Vs IgG+ area were 0.9934 for novice and 0.9437 for expert (R = 0.9626 for novice and expert combined). The inter‐rater reliability between novice and expert was higher for IgG+ area than for IgG+ fibers (R = 0.9845 and 0.9275, respectively).DISCUSSION AND CONCLUSIONWhile assessing myofiber damage histologically, measuring damaged area is more reliable than counting damaged myofibers. Moreover, measuring damaged area can be performed in about 25% of the time than counting individual damaged and intact myofibers.Support or Funding InformationSupported by a Faculty Startup Package to JAR from Wayne State University, and a grant to JAR from the Jain Foundation Inc.
Electrical Stimulation Mimics Endurance Exercise‐induced Autophagy in Skeletal Muscle
Authors: JANG YONGCHUL , KWON INSU , LANNING SARAH , SPRINGER CHARLES , LAGGAN BRETT T , COSIO‐LIMA LUDMILA , LEE YOUNGIL 
Published: November 2023

Autophagy, a cellular recycling process, plays a crucial role in maintenance of cellular function, and has emerged as a potential therapeutic strategy in chronic adult diseases such as diabetes and cancer. While muscle contraction by endurance exercise is known to cause autophagy, whether muscle contraction induced by electrical stimulation (ESTIM) can mimic an exercise effect remains unknown. Here we showed that four weeks of ESTIM (40 min/day, four days/week) upregulate autophagy flux. Four healthy female subjects, aged 18–24 years participated in the study. Prior to and post ESTIM, muscle samples were collected by a needle biopsy from quadriceps of dominant (control) and non‐dominant legs (experiment), onto which ESTIM was applied, respectively. Our data demonstrated that ESTIM significantly increased autophagic flux as evidenced by an increase in the ratio of LC3II to LC3I and LC3II levels, as well as a decline in P62 levels. Intriguingly, ESTIM‐mediated autophagy coincided with Beclin‐1 and Atg7 downregulation, whereas upregulation of BNIP3, a strong autophagy promoter ensued in response to ETIM compared to untreated muscles. Also, HSP70 reported to be a lysosome function enhancer arose by ESTIM. We assessed if ESTIM results in mitochondrial biogenesis and observed that, despite a significant decline in levels of PGC‐1α and NFR‐1, ESTIM exhibited enhanced levels of mitochondrial complex II (SDHB) in parallel with a mitochondrial transcription factor, TFAM. Taken together, our results suggest for the first time that chronic ESTIM induces autophagy in the absence of upregulation of Beclin1 and Atg7, but in the presence of BNIP3. Furthermore, ESTIM may be an important therapeutic approach that can imitate an exercise effect with regard to mitochondrial biogenesis.Support or Funding InformationThe authors gratefully acknowledge the research support for the University of West Florida Scholarly and Creative Activities Committee.
Intra Renal Bradykinin Blunted the Baroreflex Control of Renal Sympathetic Nerve Activity in Anaesthetized Rats
Authors: Akhtar Safia , Sattar Munavvar Zubaid Abdul , Rathore Hassaan Anwer , Ahmad Ashfaq , Abdullah Nor Azizan , John Edward James 
Published: November 2023

There is evidence that bradykinin (BK) results in increased afferent renal nerve activity (ARNA) which leads to sympathetic over activity. This study investigates whether bradykinin supresses high and low‐pressure baroreceptor regulation of renal sympathetic nerve activity (RSNA) in rats. Rats were anaesthetized by means of the administration of 1 mL (i.p.) of a chloralose–urethane mixture (16.5 and 250 mg mL−1 respectively). BK or saline were infused into the cortico‐medullary border of the ipsilateral kidney and RSNA recordings were made from the contralateral (left) kidney. Baroreflex gain curves for RSNA were generated by increasing and decreasing blood pressure using i.v. doses of phenylephrine and sodium nitroprusside (50 μg in a volume of 0.2 mL for each) while the low‐pressure or cardiopulmonary receptors were stimulated by infusing an acute saline volume load for 30 mins. Intrarenal infusion of BK reduced high pressure baroreflex sensitivity for RSNA by 32% (P < 0.05) compared with that of saline infused animals. Volume expansion resulted in greater renal sympatho‐inhibition by 43% (P < 0.05) in rats with saline infusion, whereas BK infused rats shows non‐significant renal sympatho‐inhibition by 12%. Intrarenal infusion of BK causes dysregulation of the arterial and cardiopulmonary baroreflexes. These findings reveal a significant role of the inflammatory mediator, BK which would blunt the normal cardiovascular homeostasis and can contribute to a deranged autonomic control.Support or Funding InformationThe authors fully acknowledge the Universiti Sains Malaysia Research Undergraduate (USM‐RU) grant (1001/PFARMASI/815078) provided by Universiti Sains Malaysia, Malaysia.Safia Akhtar is a recipient of a USM Fellowship [P‐FD0091/11(R)] from the Institute of Post‐Graduate Studies (IPS), Universiti Sains Malaysia (USM), Penang, Malaysia