bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sexual Dimorphism in Substrate Metabolism During Exercise
Authors: Abo Stéphanie , Casella Elisa , Layton Anita 
Published: May 2024

During aerobic exercise, women oxidize significantly more lipids and less carbohydrates than men. This sexual dimorphism in substrate metabolism has been attributed, in part, to the observed differences in epinephrine and glucagon levels between men and women during exercise. To identify the underpinning candidate physiological mechanisms for these sex differences, we developed a sex-specific multi-scale mathematical model that relates cellular metabolism in the organs to whole-body responses during exercise. We conducted simulations to test the hypothesis that sex differences in the exercise-induced changes to epinephrine and glucagon would result in the sexual dimorphism of hepatic metabolic flux rates via the glucagon-to-insulin ratio (GIR). Indeed, model simulations indicate that the shift towards lipid metabolism in the female model is primarily driven by the liver. The female model liver exhibits resistance to GIR-mediated glycogenolysis, which helps maintain hepatic glycogen levels. This decreases arterial glucose levels and promotes the oxidation of free fatty acids. Furthermore, in the female model, skeletal muscle relies on plasma free fatty acids as the primary fuel source, rather than intramyocellular lipids, whereas the opposite holds true for the male model. This work was supported by the Canadian Institutes of Health Research (CIHR) and the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery award. 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.
Inflammatory Responses of the Remote Organs After Tourniquet-Induced Ischemia-Reperfusion in Mouse Hindlimb
Authors: Xu Linda , Klammer Abigail , Whitney Lauren , Tu Huiyin , Barksdale Aaron , Wadman Michael , Li Yu-Long 
Published: May 2024

Tourniquet use is the most effective tool for controlling life-threatening extremity hemorrhage before other treatments and for creating bloodless operating fields in surgical procedures. However, tourniquet-induced ischemia-reperfusion (IR) also causes skeletal muscle injury and associated secondary end-organ damage. Our previous studies have demonstrated that there are involvements of inflammatory cytokines in tourniquet-induced skeletal muscle IR injuries. The objective of this study is to investigate the inflammatory responses of end-organs after tourniquet-induced mouse hindlimb IR. We hypothesized that tourniquet use would result in an inflammatory response in the remote organs. The unilateral hindlimbs of mice were subjected to 3 hours of tourniquet application by placing a rubber band at the hip joint. Then the rubber bands were released for reperfusion over different periods of time (1, 3, 7, and 14 days). The mRNA levels of IL-1β and TNFα (two inflammatory cytokines) in the lungs, liver, kidneys, and heart were measured using real-time RT-PCR analysis. In the lungs, the levels of IL-1β and TNFα mRNA were significantly elevated at day 1 after tourniquet-induced IR, then decreased at days 3 and 7, and returned to a high level at day 14. In the liver, the levels of IL-1β and TNFα mRNA were increased at day 1 and remained at a high level until day 14. However, tourniquet-induced hindlimb IR did not change the levels of IL-1β or TNFα mRNA in the kidneys or heart during the whole period of tourniquet-induced IR. In conclusion, these results suggest that the inflammatory response to tourniquet-induced hindlimb IR is different among distant organs, which will help to develop therapeutic strategies for different end-organs after tourniquet-induced hindlimb IR. NIH/NIGMS 1R01GM145736 to Y-LL. 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.
Regulatory Effect of L-Cysteine on Testosterone Biosynthesis Genes in Leydig Cells and THP-1 Monocytes
Authors: Justin Margret Jeffrey , Jain Sushil K 
Published: May 2024

Background: Spermatogenesis involves a series of complicated cellular events resulting in the production of mature spermatids. Leydig cells of the testis are essential to forming a spermatozoon. Leydig cells are the interstitial cells that reside between seminiferous tubules and their key role is in the biosynthesis of testosterone. Leydig cells also regulate testicular macrophage and are stocked with innate defense systems. CYP11A1 is a major enzyme in the biosynthesis pathway of testosterone which converts the cholesterol to pregnenolone in the mitochondria of Leydig cells. L-Cysteine (L-Cys) acts as a precursor of glutathione, an antioxidant that plays a vital role against oxidative stress damage. Previous animal studies report the protective effect of L-Cys against chemical/radiation-induced-testicular damage. This study examined the biochemical mechanisms by which L-Cys stimulates testosterone biosynthesis and relative expression of blood-testis barrier (BTB) genes in Leydig cells and THP-1 monocytes. Methodology: The THP-1 monocytes and Leydig cells were treated with L-Cys for 24 hours. Following treatment, RNA was extracted, and the expression of the testosterone biosynthesis gene and BTB genes was analyzed using quantitative RT-PCR. Data (n=4) is presented as mean ± SEM and p-values ≤0.05 are considered as significant. Results: Expression of CLDN1 (p=0.006), CLDN11 (p=0.03), and TJP1 (p=0.04) genes was significantly higher in Leydig cells than in the THP-1 monocytes. There is no significant change in the expression of testosterone-regulatory genes between Leydig cells and THP-1 monocytes. In THP-1 monocytes, L-Cys treatment significantly upregulated the expression of CYP11A1 (p=0.03), CYP19A1 (p=0.002), and BTB genes: CLDN1 (p=0.05), CLDN2 (p=0.001), CLDN4 (p=0.0006), CLDN11 (p=0.006), and TJP1 (p=0.03). Similarly, L-Cys (500uM) treatment significantly upregulated (p=0.03) the CYP11A1 gene expression in HLC, further, the expression of BTB genes: CLDN1 (p=0.03), CLDN11 (p=0.02), and TJP1 (p=0.02) was also upregulated. Conclusion: This study shows that L-Cys increases the expression of testosterone-related genes in both HLC and THP-1. The expression profile of the BTB genes was higher in HLC than in THP-1 monocytes. L-Cys supplementation upregulates the expression of the testosterone biosynthesis pathway gene which can increase spermatogenesis and reduce the male infertility risk. Funding source: NIH/NCCIH (5R33AT010637) and the Malcolm Feist Endowed Chair in Diabetes. 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.
Empagliflozin Mitigates TMAO-Induced NLRP3 Inflammation and Alters Transporter Expression in Renal Proximal Tubular Cells
Authors: Huang Chiang-Chi , Yang Jenq-Lin 
Published: May 2024

The gut-microbe-derived metabolite, trimethylamine N-oxide (TMAO), not only exhibits elevated levels but also serves as a predictor of higher mortality in patients with chronic kidney disease (CKD). In additional to CKD, elevated TMAO levels were also observed in organic anion transporter 3 (OAT 3) knockout mice and in the presence of trimethoprim, an antibiotic known for inhibiting multiple transporters on renal proximal tubule (PT) cells. These findings suggest that plasma TMAO level is a marker for diminished transporter function in PT cells. Moreover, the pro-inflammatory effects of TMAO on PT cells is relatively underexplored. Besides reno-protective effect, a recent study has shown that the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagliflozin attenuates hyperuricemia by enhancing efflux transporter function. Therefore, we propose that empagliflozin can ameliorate TMAO-induced inflammation in PT cells by regulating the expression of membrane transporters. Western blotting results revealed that empagliflozin mitigated TMAO-induced NLRP3 inflammatory cytokines IL-1β, and IL-18. Additionally, empagliflozin reduced the elevated serum levels of TMAO in a CKD mouse model resulting from 5/6 nephrectomy (5/6Nx). Immuno-fluorescent staining demonstrated that TMAO decreased the expression of the basolateral transporter organic anion transporter 1 (OAT1) but increased the expression of apical membrane transporters ATP-binding cassette super-family G member 2 (ABCG2) on the PT cells of 5/6Nx mice. Our in vitro study indicated that TMAO reduced the expression of basolateral membrane transporters OAT1 and OAT3. But empagliflozin significantly increased the expression of OAT3 and ABCG2 in TMAO-treated HK-2 cells. In summary, TMAO induced NLRP3 inflammation in PT cells, while empagliflozin ameliorated the inflammation. Empagliflozin also lowered TMAO levels and influenced transporter expressions in a CKD mouse model. In conclusion, we have shown that empagliflozin mitigate TMAO-induced NLRP3 inflammation. Beyond inhibiting SGLT2, empagliflozin possesses additional effect on the expression of membrane transporters in PT, particularly in CKD mice. This research was funded by Chang Gung Medical Foundation CMRPG8K0011 and CMRPG8M0311. 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.
Serum Proteins Infer Molecular Protection Against Inflammation in Weddell Seal (Leptonychotes weddellii) Blood
Authors: Klink Amy C , Bagchi Aranya , Hindle Allyson G 
Published: May 2024

Weddell seals ( Leptonychotes weddellii) are elite divers able to dive up to 900 meters deep and remain submerged for over 90 minutes. Weddell seals have a dramatic dive response to allow for longer, deeper dives including intense bradycardia and constriction of blood vessels, especially those supplying peripheral or visceral organs. Vasoconstriction, hypo-perfusion and subsequent re-oxygenation upon surfacing is known to induce tissue injury in terrestrial mammals via inflammation. Previous work interrogating the Weddell seal’s innate immune system suggested a component in the seal’s blood serum that protects against inflammation. We are using a mouse macrophage (RAW 264.7) cell model to characterize components of the seal’s blood that are anti-inflammatory to lipopolysaccharide (LPS). When exposed to 10 ng/mL LPS, RAW cells supplemented with deproteinated serum from adult Weddell seals lose their protection against inflammation, having 11-fold greater induction of interleukin-6 (IL-6) mRNA expression after a 6-h exposure compared to RAW cells supplemented with intact seal serum (T=3.29, p=0.01). To determine whether anti-inflammatory capacity of serum is innately present in Weddell seals or whether it is acquired in conjunction with development of diving capacity, we compared the protective effects of adult Weddell seal serum against serum from Weddell seal pups collected at approximately their age of weaning, when they had begun diving activities but do not yet dive deep. Following exposure to 10 ng/mL LPS, IL-6 expression was 69% lower in RAW cells supplemented with serum from adult seals compared to those supplemented with serum from pups (T=8.41, p=0.002), suggesting that ontogeny or diving behavior contributes to the development of anti-inflammatory serum. Analysis of adult (n=12) and pup (n=11) serum proteomes revealed a single protein, colony stimulating factor 2 receptor subunit beta (CSF2RB), with a 24-fold higher abundance in adults (PFDR<0.0001). CSF2RB is a pleiotropic cell surface receptor subunit with known functions in innate immunity, erythropoiesis, as well as tissue protection. Therefore, we hypothesize that it plays a role in the anti-inflammatory protection observed in adult seals. Defining the mechanism of action for this protein in seal serum could identify a protective adaptation that facilitates deep and long dives. In a broader context, lessons learned from an extreme diving mammals may identify anti-inflammatory strategies with new clinical relevance. NSF #1921491; #1853326; #2337400. 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.
Identifying associations of human surfactant protein A SNPs and allelic variants with retinopathy of prematurity
Authors: Colon Montanez Keishla , Brass Kelsey , Rousselle Dustin , Aston Christopher , Silveyra Patricia , Bhatti Faizah 
Published: May 2024

Retinopathy of prematurity (ROP) is the primary cause of childhood blindness worldwide. Previous studies showed that allelic single nucleotide polymorphic (SNP) variants of the human surfactant protein A genes (SP-A1, SP-A2) are associated with the development of respiratory distress syndrome and bronchopulmonary dysplasia (BPD). In this work, we hypothesized that SP-A SNPs and allelic variants are associated with altered risk of ROP in prematurely born infants. To test this hypothesis, we used a modified PCR-based method to detect variants of the SP-A1 and SP-A2 genes in a cohort of preterm infants. Infants born at <32 weeks’ gestation and/or<1500 grams were enrolled. Scavenged blood samples or cheek swabs were collected and DNA was extracted using the QIAamp DNA Mini Kit. We measured SNPs in SP-A1 and SP-A2 using Taqman probes for allelic discrimination by PCR or PCR/RFLP/sequencing method. Associations of SP-A1 and SP-A2 SNP allele frequencies with ROP and BPD were determined using chi-square and logistic regression analyses. Our results show that, of the total patient cohort (n=59), 42 patients had a BPD diagnosis (23 with ROP and 36 without ROP). DNA analysis of these samples identified associations of SP-A1 and SP-A2 SNPs and variants with ROP. For SP-A1, the following SNP associations were found for ROP using chi-square: rs1059047 (p=0.44), rs1136450 (p=0.63), rs1136451 (p=0.21), rs1059057 (p=0.52). For SP-A2, the following SNPs associations were identified with ROP: rs1059046 (p=0.51), rs17886395 (p=0.050), rs1965707 (p=0.031), rs1965708 (p=0.46). Logistic regression analysis indicated an association of ROP with the SP-A1 6A2 variant (p-value = 0.47, OR (6A2/*)=0.8036, 95%CI [0.2299 - 2.8082], OR (6A2/6A2) = 0.4327, 95%CI [0.1063 - 1.7615]), which conferred protection, as well as an association of ROP with SP-A2 6A2 (p-value = 0.0055) with decreased risk when 1A2 variant is present. We conclude that SP-A1/SP-A2 polymorphisms are associated with the presence of ROP in infants with BPD. The 6A4 SP-A1 and SP-A2 1A2 appear to confer protection in babies against ROP. Further studies will determine the mechanisms of this protective effect. Indiana University, University of Chicago Metcalf Internship Program Grant, The University of Oklahoma Health Sciences Center. 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.
Pathogenic Mechanisms Activated by NSD2 Translocations in Multiple Myeloma
Authors: Ma Guiru , Vasilyev Mikhail , Tripathi Chakrapani , Jedlicka Charles , Bates Melissa , Tomasson Michael 
Published: May 2024

The NSD2 gene is overexpressed in multiple cancers and is associated with cancer cell proliferation, invasion, and metastasis. NSD2 gene is universally present in multiple myeloma (MM) patients with t(4;14) (p16;q32) translocation, a high-risk subtype. NSD2 is characterized by different breakpoints. NSD2Δ3 breakpoint is associated with shorter survival than other breakpoints. NSD2Δ3 contains non-coding RNA ACA11 within intron 18. Additionally, 80% of t(4;14) MM patients lack the retinoblastoma tumor suppressor gene (RB1). We hypothesize that ACA11 cooperates with RB1 loss in MM pathogenesis. Also, we hypothesize that NSD2Δ3 increases protein expression driving myeloma growth. To overexpress NSD2WT, snoACA11, and NSD2Δ3 in cells, we cloned NSD2WT, and NSD2Δ3 plasmid constructs in a murine stem cell virus (MSCV)-IRES- GFP vector. We isolated primary B cells from RB1 wild-type and knock-out mice by CD43 microbeads and transduced those cells using a virus containing ACA11 and NSD2WT. ACA11 overexpression significantly increased B cell proliferation in Rb1dKO mice. This hyperproliferative phenotype is induced by reactive oxygen species (ROS) levels. However, we did not find a further increase in B cell proliferation with co-overexpression of NSD2WT and ACA11 in Rb1dKO mice. We demonstrated increased protein stability by finding higher NSD2Δ3 protein expression compared to NSD2WT protein expression in HEK293T cells. These results support our hypothesis and demonstrate oncogenic role of ACA11 in t(4;14) MM. Future work will be done to determine the cell biological effects of NSD2Δ3 and establish its role in myeloma pathogenesis. Completion of this study will advance understanding of this epigenetic NSD2 gene and potentially develop targeted drugs for NSD2, providing more individualized treatment options for these patients. University of Iowa Department of Internal Medicine. 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.
Intact DNA Repair in Differentiated Cardiomyocytes Is Essential for Maintaining Cardiac Function in Response to Pressure Overload in Mice
Authors: de Boer Martine , Hoeijmakers Jan H.J. , Duncker Dirk J. 
Published: May 2024

Introduction: DNA in every cell is continuously damaged and DNA repair mechanisms are essential for protection against DNA damage-induced aging-related diseases. For example, deficient repair of endogenously generated DNA damage in mice with cardiomyocyte-restricted inactivation of Xpg, is associated with progressive heart failure (de Boer et al. Aging Cell 2023). Here we tested the hypothesis that unrepaired DNA damage in differentiated cardiomyocytes increases cardiac vulnerability in response to hemodynamic overload. Methods: At 8 weeks of age, αMHC-Xpgc/- and control (Ctrl) mice were subjected to pressure overload by mild transverse aortic constriction (TAC). Eight weeks after TAC, left ventricular (LV) function was assessed using echocardiography and hemodynamic measurements, followed by histological and molecular analyses. Results: Cardiomyocyte-restricted inactivation of Xpg resulted in systolic as well as diastolic LV dysfunction. TAC-induced LV hypertrophy was similar in both groups (Ctrl 38%; αMHC-Xpgc/- 34%). In Ctrl mice, LV hypertrophy was accompanied by minimal LV dilation and only modest changes in systolic and diastolic LV function. Conversely, TAC in αMHC-Xpgc/- produced severe LV dilation and dysfunction and resulted in overt backward failure, demonstrated by marked increases in LV end-diastolic pressure, left atrial weight and lung fluid weight. These changes were accompanied by further increases in the expression levels of the hypertrophic marker genes atrial natriuretic peptide and beta-myosin heavy chain. Moreover, lectin staining revealed a decrease in capillary density and TUNEL staining revealed further elevated levels of myocardial apoptosis in αMHC-Xpgc/--TAC mice as compared to Ctrl-TAC mice. In addition, a significant increase of myocardial collagen content was observed in αMHC-Xpgc/--TAC but not in Ctrl-TAC mice. Conclusion: Cardiomyocyte-restricted loss of DNA repair protein Xpg increases cardiac vulnerability to develop heart failure in response to pressure-overload. These findings underscore the importance of genomic stability for maintenance of cardiac function, not only under basal conditions, but also during increased cardiac loading conditions. Supported by the Dutch Heart Foundation [Grants 2017B018-ARENA-PRIME; 2021B008-RECONNEXT]. 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.
Activation of Piezo-1 Prevents Human Microvascular Endothelial Dysfunction During Acute Inhibition of Ceramide Formation
Authors: Jaramillo-Torres Maria Jose , Senthilkumar Gopika , Lindemer Brian , Bordas-Murphy Henry , Freed Julie K. 
Published: May 2024

Despite the well-known damaging effects of elevated intracellular ceramides on human microvascular function, our recent work has shown that inhibition of ceramide formation through neutral sphingomyelinase (NSmase) promotes endothelial dysfunction in arterioles from healthy adults, manifested as endothelial production of hydrogen peroxide (H2O2), rather than nitric oxide (NO), in response to flow (flow-induced dilation; FID). Recent evidence suggests that ceramide prevents inactivation of Piezo-1, a shear-sensitive Ca2+ channel and inhibition of Piezo-1 reduces endothelial nitric oxide synthase (eNOS) activation in response to flow. Together, we hypothesized that ceramide-induced Piezo-1 activation is required to maintain NO-mediated FID in human microvessels and thus agonism of Piezo-1 during NSmase inhibition will prevent endothelial dysfunction. Arterioles (100-250μm) from healthy adults were dissected from discarded surgical adipose tissue. Vessels were cannulated in organ chambers, pre-constricted with endothelin-1, and changes in internal diameter in response to increases in flow were measured with videomicroscopy. Peroxy yellow 1 (PY1) fluorescent probe was used to assess endothelial H2O2 production in human umbilical vein endothelial cells (HUVECs). Mean% maximal dilation or fluorescent intensity±SE with two-way repeated measures ANOVA is reported. FID was preserved with Piezo-1 agonism (Yoda-1, 1μM, 30min) during NSmase inhibition (GW4869 4μM, 30min; 73±16.8, n=4 vs control 73±8.2, n=9; p>0.05), however FID was diminished in the presence of the eNOS inhibitor L-NAME (100μM; -2.6±11.3, n=5; p<0.05). A similar switch to NO-mediated FID was seen with C2-ceramide (5μM)+GW4869 (70.1±9.7 vs +L-NAME -3±9.7, n=4 both; p<0.05). NSmase inhibition increased H2O2 production in HUVECs (5.2±7.4 vs 83.0±31.6, n=6; p<0.05), an effect that was diminished with Yoda-1 (5.1±7.5, n=4; p<0.05) and C2-ceramide (10.7±9.2, n=5; p<0.05). These data suggest a role for Piezo-1 in NSmase-induced NO-signaling and provide mechanistic insight into how ceramide may exert beneficial effects within the human microvasculature. This research is supported by the National Institute of Health (NHLBI) R01HL160752 (JKF) and the American Heart Association (AHA) Predoctoral Fellowship 909315 (GSK). 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.