bluuebunny/crossref_metadata_2025_split huggingface dataset:
TRPC6 deficiency attenuates renal injury and mitochondrial dysfunction in ischemia/reperfusion-induced acute kidney injury
Authors: Wang Zhen , Fu Yiling , Dai Xuemei , do Carmo Jussara , da Silva Alexandre , Mouton Alan , Li Xuan , Omoto Ana , Hall John 
Published: May 2023

Ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) is a major clinical problem without effective therapy and is a significant cause of morbidity and mortality during the perioperative period. The hallmarks of I/R-AKI include renal tubular cell injury and mitochondrial dysfunction. Transient receptor potential channel subfamily C member 6 (TRPC6), a non-selective cation channel that mediates the influx of calcium and other monovalent cations into cells, is widely expressed in the kidney, including proximal tubular cells. TRPC6 deficiency has been reported to be protective in chronic kidney diseases by reducing oxidative stress; however, its role in AKI is still controversial. In this study, we examined the role of TRPC6 during the early phase of renal injury in I/R-induced AKI. To reduce the severity and limit variability in kidney injury after I/R, we performed unilateral I/R surgery with 30 minutes of ischemia in the left kidney of 22-week-old male wild-type (WT) and whole-body TRPC6 knockout (TRPC6 KO) mice. Mitochondrial respiration rate and mitochondria-generated superoxide in the left kidney were examined 18 hours after I/R surgery by OROBOROS Oxygraph Respirometry. Serum creatinine and urinary neutrophil gelatinase-associated lipocalin (NGAL) concentration were determined in addition to histological evaluation by PAS staining in WT and TRPC6 KO mice. Our results show that the mitochondrial oxygen consumption rate was significantly higher in I/R kidneys from TRPC6 KO mice compared to WT (56.5±9.3 vs. 22.9±2.0 pmol/min/mg, n=5-6). Despite higher mitochondrial respiration, mitochondria-generated superoxide production was significantly lower in the kidney of TRPC6 KO mice. TRPC6 KO mice also exhibited significantly lower serum creatinine (0.26±0.02 vs. 0.37±0.08 mg/dL, n=7-10) and urinary NGAL levels (526.6±58.7 vs. 1313.5±192.0 ng/mL, n=6-10) than WT mice. Renal histology showed that I/R kidneys from TRPC6 KO mice have reduced tubular cell death in outer medulla areas and decreased tubular clots and inflammatory cell infiltration. These observations suggest that TRPC6 deficiency may be protective during the early phase of I/R-induced AKI by preserving mitochondrial respiration and attenuating mitochondria reactive oxygen species generation. Targeting TRPC6 and its downstream signaling pathways may provide new avenues for future I/R-induced AKI therapies. (NIDDK R00DK113280 and R01DK121411, NIGMS P20GM104357 and NIGMS U54GM115428) This is the full abstract presented at the American Physiology Summit 2023 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.
Role of Nrf2 in myocardial infarction and ischemia-reperfusion injury
Authors: Zuberi Sahar , Rafi Hira , Hussain Azhar , Hashmi Satwat 
Published: May 2023

Background: Myocardial infarction (MI) is a leading cause of morbidity and mortality in the world and is characterized by ischemic necrosis of an area of the myocardium permanently devoid of blood supply. With advancements in therapeutics, thrombolytic agents and primary percutaneous coronary intervention (PCI) can now be employed to reperfuse the ischemic area. Reperfusion, in itself generates reactive oxygen species and this causes further insult to the myocardium, thereby resulting in ischemia-reperfusion (IR) injury. Since Nrf2 is a key regulator of redox balance, it essential to determine its contribution in these two disease processes. Conventionally Nrf2 levels have been shown to rise immediately after ischemia and reperfusion but its contribution to disease process in the days that follow remains uncertain. Objective: This study intended to demonstrate the difference in Nrf2 levels one week after myocardial infarction and ischemia-reperfusion injury, respectively. Methods: Mice were divided into MI, IR injury and sham surgery group and were sacrificed 1 week after surgery. In MI model, left anterior descending artery was ligated permanently while in IR model, it was temporarily ligated for 30mins and reperfused. Infarct size was estimated using trichrome staining and expression of Nrf2 was assessed using immunohistochemistry, Western blot and ELISA. Results: Infarct size was the highest in MI group, followed by IR (MI: 31.02 ± 1.45%, IR: 13.03 ± 2.57%; p < 0.01). We observed a significantly higher expression of Nrf2 in MI group compared to IR model using immunohistochemistry, spot densitometry of Western blot (MI: 2.13 ± 0.22, IR: 1.69 ± 0.25; p = 0.039) and ELISA (MI: 80.78 ± 27.08, IR: 31.97 ± 4.35; p < 0.01). Conclusion: There is a significantly higher expression of Nrf2 in MI compared to IR injury group. Modulation of Nrf2 could be a potential target for therapeutics in the future, and its role in cardiprotection can be further investigated. Aga Khan University University Research Council Funding This is the full abstract presented at the American Physiology Summit 2023 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.
Therapeutic Potential of Extracellular Vesicles to Restore Alcohol-mediated Impairment of Myoblast Differentiation
Authors: Simon Liz , Bourgeois Brianna , Molina Patricia 
Published: May 2023

At-risk alcohol use in people living with HIV (PLWH) and chronic binge alcohol (CBA) administration in simian immunodeficiency virus (SIV)-infected macaques are associated with dysfunctional skeletal muscle mass. Our studies have shown that decreased myomiR-206 expression in skeletal muscle and myoblasts isolated from CBA/SIV macaques contributes to decreased myoblast differentiation. miRs transported in extracellular vesicles (EVs) mediate numerous cellular responses through intercellular communication. This study tested the hypothesis that delivery of miR-206 in EVs would ameliorate CBA-mediated decreased myoblast differentiation. Eight female rhesus macaques received either (CBA, 2.5g/kg/day) or water (VEH) for 14.5 months. Three months following the initiation of CBA/VEH, animals were infected with SIVmac251 and initiated on antiretroviral therapy 2.5 months later. Myoblasts were isolated from the vastus lateralis muscle at study endpoint (blood alcohol concentration= 0 mM) from each animal and used for ex vivo experiments including measuring differentiation, transfecting with a miR-206 mimic, and isolating EVs from myotube culture supernatant via ultracentrifugation. Myoblast differentiation measured by fusion index was lower in CBA myotubes compared to VEH (p<0.05). CBA decreased myotube-derived EV miR-206 expression (p<0.01). Transfection of myoblasts isolated from the CBA group with a mir-206 mimic increased myotube fusion index (p<0.05). Moreover, delivery of exogenous miR-206 in plasma-derived EVs increased myotube expression of miR-206 by over 450-fold (p<0.001) and significantly improved myoblast differentiation as measured by fusion index and myotube density (p<0.05). These results provide evidence that delivering miR-206 through EVs can increase CBA-mediated SKM stem cell differentiation. We propose these findings support the possible use of autologous plasma EVs as therapeutical vehicles devoid of the known adverse effects of synthetic cargo nanocarriers. Supported by: NIH/NIAAA P60AA009803, F30AA029358, K01AA024494. This is the full abstract presented at the American Physiology Summit 2023 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.
Gestodene, a Positive Allosteric Modulator of PAR1, Enhances PAR1-Mediated Morphological Changes in MEG-01 Cells
Authors: Park So-Hyeon , Heo Yunkyung , Lee Yechan , Jeon Hyejin , Namkung Wan 
Published: May 2023

Protease-activated receptor 1 (PAR1) is a high-affinity thrombin receptor expressed in human platelets and can be activated by low levels of thrombin. Selective inhibition of PAR1 by vorapaxar significantly inhibits thrombin-induced calcium mobilization in human platelets and increases the risk of bleeding, suggesting that positive allosteric modulator (PAM) of PAR1 may increase the risk of thrombosis. In the present study, we performed a cell-based screening to identify novel PAMs of PAR1 and found gestodene, which acts as PAM of PAR1. Gestodene enhanced both thrombin- and PAR1-AP-induced increases in intracellular calcium levels through PAR1 in a dose-dependent manner, but it did not alter the activity of PAR2 and PAR4. Gestodene increased PAR1-AP-induced internalization of PAR1 receptors and phosphorylation of ERK1/2, and the enhancing effects were significantly blocked by vorapaxar. Furthermore, gestodene potently increased PAR1-AP-induced morphological changes in the human megakaryoblastic leukemia cell line MEG-01 cells, a cellular model of PAR1-mediated morphological changes in platelets. Our results reveal that gestodene is a selective PAM of PAR1 and provide a molecular basis for the risk of venous thromboembolism induced by oral contraceptives including gestodene. This research was supported by a Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1A6A1A03023718). This is the full abstract presented at the American Physiology Summit 2023 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.
Alveolar macrophages undergo METosis in an inflammatory model of neonatal lung injury
Authors: Higazy Randa , Mohammadi Atefeh , Ivanovska Julijana , Tran Harvard , Gauda Estelle , Palaniyar Nades 
Published: May 2023

Background: Activated macrophages can produce macrophage extracellular traps (METs) - DNA strands coated with cytotoxic components that are released to immobilize pathogens and control infection. However, METs can also contribute to the inflammatory process and lead to severe tissue damage. Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature infants initiated by inflammation and oxidative stress. Gram-negative bacteria and candida increase the risk of developing BPD and are strong inducers of extracellular traps. Macrophages are the most abundant immune cells in the neonatal lung tissue, responsible for controlling the inflammatory process. We aimed to determine whether inflammation triggers METosis in a neonatal model of inflammatory lung injury. Methods: Alveolar macrophages (AMs) from bronchoalveolar lavage fluid (BALF) were isolated from Sprague Dawley rat pups on postnatal day (PND) 8. In vitro - AMs were incubated with METosis agonists (lipopolysaccharide [LPS] and phorbol myristate acetate [PMA]) or control (media) for 4h. Cells were fixed and stained for markers of METosis (myeloperoxidase [MPO] and citrullinated histone H3 [CitH3]) and DNA (DAPI) for immunofluorescence imaging. In vivo - PND6-9 pups were treated with LPS or saline intrapharyngeally and DNase enzyme or saline intraperitoneally. BALF was collected on PND10. BALF was analysed using immunofluoresence imaging and picogreen assay. Results: Immunofluorescence imaging of neonate AMs showed increased expression of METosis markers MPO, CitH3, and DNA strands with in vitro exposure to METosis agonists PMA or LPS compared to control (n =3). In vivo LPS exposure also showed evidence of increased extracellular trap formation in the BALF collected from neonate rat lung compared to control (n=3; p<0.0001); further, rats exposed to both LPS and DNAse enzyme showed decreased extracellular trap formation (p = 0.002) in comparison to the rats exposed to LPS and saline. Conclusions: To the best of our knowledge, this study is first to establish (i) rat AMs undergo METosis, (ii) a plausible role for METosis in lung injury (iii), and the potential relevance of METosis in lung injury during early development. Novel therapies targeting METosis formation may reduce lung inflammation contributing to BPD in premature infants. This work was supported by the Women's Auxiliary Fund, The Hospital for Sick Children, Toronto, Ontario, Canada This is the full abstract presented at the American Physiology Summit 2023 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.
Limb bone response to exercise training in High Runner (HR) mice
Authors: Horner Angela , Rawlings Diamond , Guzman Duron Luis , Garland Theodore 
Published: May 2023

Physical activity is a primary determinant of musculoskeletal health in vertebrates. The amount and intensity of exercise activity can impact bone morphology and density, muscle fiber type, and the material properties of passive elastic tissues such as tendon and ligaments. To further investigate the role of exercise intensity and duration on bone remodeling, we examined the effects of exercise in a unique model, a line of mice selectively bred for high voluntarily wheel running (high runner, HR) for over 90 generations. We placed HR and control line mice in cages equipped with data logging wheels for a minimum of 9-10 week training periods. Morphometric data collected from humera and femora revealed that exercised mice tended to have shorter, thinner limb bones regardless of genotype. HR mice had longer and thicker femora than control mice, but no significant morphological differences were apparent in humera. Distal femora width correlated with frequency of wheel running, and as HR mice outran control line mice threefold (in average revolutions/day) there was a significant interaction of genotype and exercise intensity. Our data support that the intensity and frequency of running impact limb bone morphology, and that hindlimbs are more responsive than forelimbs both to loading and selective breeding. This is the full abstract presented at the American Physiology Summit 2023 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.
Intrinsic aerobic capacity and hepatic mitochondrial function influences fecal energy and bile acid excretion
Authors: Kugler Benjamin , Rickabaugh Madi , Hightower Gabrielle , Lysaker Colton , Wilkins Heather , Thyfault John 
Published: May 2023

Low aerobic capacity (i.e., capacity to utilize oxygen in metabolic pathways) has proven to be a risk factor for hepatic steatosis. We have previously reported that increased hepatic mitochondrial function caused by exercise and high aerobic capacity is associated with higher fecal bile acid loss. In addition, other labs have shown that bile acid sequestrants (BA-seq) that block bile acid absorption in the gut and drives-up fecal bile acid loss is associated with an upregulation of hepatic mitochondrial function. So far, the connection between bile acid metabolism and mitochondrial function is unknown. Here we utilized rats artificially selected to be higher-capacity runners (HCR) and low-capacity runners (LCR) with distinct intrinsic aerobic capacities and hepatic mitochondrial function. We hypothesized that aerobic capacity would induce distinct differences in fecal bile acid loss and mitochondrial function when on a BA-seq. Male and female HCRs and LCRs (8 months of age) were randomly assigned to either a low-fat diet (LFD, 10% fat), high-fat diet (HFD, 45% fat), or HFD with cholestyramine (i.e., BA-Seq) for 24 weeks. Animals were euthanized, and feces and livers were collected. Fresh mitochondria were then isolated from the liver, and mitochondrial respiration and H2O2 emission was analyzed (O2k high-resolution respirometry). Statistical analysis was performed by a three-way ANOVA within sex with an alpha set at 0.05. BA-Seq increased fecal energy loss and BA content more than control diets (P<0.05 main effect of BA-Seq). However, HCRs with a BA-seq have greater fecal BA content than their LCR counterpart on a BA-Seq (P<0.05). Interestingly, male and female HCR livers displayed elevated hepatic mitochondrial respiration rates (State 2, State 3, FCCP) and mitochondrial coupling efficiency (State 2/State 3) and a reduction in free radical production (H2O2:O2) utilizing a fatty acid fuel source compared to LCRs (P<0.05, main effect of strain). However, diet and BA seq did not alter mitochondrial function in either strain. Overall, we provide evidence that elevated intrinsic aerobic capacity promotes greater sensitivity to BA-seq. However, enhanced fecal energy and BA loss do not alter hepatic mitochondrial function regardless of intrinsic aerobic capacity. R01DK121497 This is the full abstract presented at the American Physiology Summit 2023 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.
Alterations in the Placental Endothelin-1 System in Response to Hypoxia and Chronic Ischemia
Authors: George Eric , Chapman Heather , Franklin Joshua , Lartigue Elecia , Murphy Hayley 
Published: May 2023

Preeclampsia is one of the most common obstetrical complications, commonly characterized by new onset hypertension and proteinuria or other markers of end organ injury. In patients with preeclampsia, the arteries supplying the placenta develop abnormally, resulting in placental ischemia; widely believed to be responsible for the pathophysiology of this disorder. While the placenta is responsible for nutrient and waste exchange, it also releases numerous hormones from its interstitial and syncytialized trophoblasts important in pregnancy. Placental ischemia causes changes in placental hormone function, including endothelin-1 (ET-1). While ET-1 was initially characterized as a vasoconstrictor, it has been shown to be an important regulator of inflammatory and metabolic processes through its two receptors (ETA or ETB), though little is known about the role of the ET-1 system in the placenta. We hypothesized that chronic placental ischemia in vivo, and isolated hypoxia in vitro, would induce significant alteration in the expression of these individual components of the endothelin-1 system. Using the rodent reduced uterine perfusion pressure (RUPP) model to induce placental ischemia, we found that there was a significant (122±32 vs 45±12, p=0.05) decrease in the normalized expression of ETB, with a strong trend (112±26 vs 185±25, p=0.072) to increased ET-1 expression as measured by qRT-PCR. Interestingly, when we syncytialized BeWo choriocarcinoma cells and exposed them for 48 hours to oxygen tensions found in healthy (8%) and ischemic (1%) placentas, we found significant increases in ET-1 (205±79 vs 489±103, p=0.04), ETA (85±31 vs 276±67, p=0.04, and ETB (100±44 vs 388±68, p=0.05) gene expression. This suggests that individual cell types within the placenta are exhibiting differential response in endothelin signaling in response to hypoxia. The effect of endothelin on production of inflammatory cytokines was then determined. Compared to control (106±17) cells, both an ETB antagonist (163±12, p<0.05) and ET-1 itself (179±17, p<0.05) increased normalized TNF-α expression. Likewise, compared to controls (102±9), expression of the anti inflammatory IL-6 was significantly decreased with both ET-1 (69±11, p<0.05) and an ETA antagonist (70±9, p<0.05), suggesting that dysregulation of ET-1 signaling due to hypoxia could be an important regulator of inflammation in preeclampsia. Taken together, these data suggest that the placental ET-1 system could be a potential point of intervention for the management of preeclampsia. P01HL51971, P20GM104357, and R01HL137791 This is the full abstract presented at the American Physiology Summit 2023 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.
Effects of traumatic brain injury on blood pressure regulation and cardio-renal function in rats
Authors: Lorenz John , Sakthivel Srikumaran , Lorenz Suzanne , Nieman Michelle 
Published: May 2023

Traumatic Brain Injury (TBI) affects around 68 million people worldwide annually. While the neurologic effects of TBI have been extensively studied, potential effects on the autonomic nervous system have received less attention, despite clinical observations of autonomic dysfunction. We therefore sought to develop a rat model of repeated traumatic brain injury to examine the effects on cardiovascular and renal regulation, and we hypothesized that TBI would result in autonomic dysregulation of cardio-renal function. TBI was induced in male rats (250-300 gBW) under brief isoflurane anesthesia by dropping a 245g weight from a height of 1-1.5 meters onto the mid-sagittal area of the skull while the rat was suspended on a perforated tear-away platform. In the first series of experiments, blood pressure was measured continuously by telemetry over a two-week period, while rats were subjected to three successive injuries, each separated by 48 hours (repeated TBI, rTBI). Mean blood pressure was found to increase by about 7 mmHg following the third TBI (104.0 ± 1.1 to 111.0 ± 1.3 mmHg; p < 0.001, n=9). Though mild, the elevation in blood pressure was highly consistent, occurring in all of the injured rats. There were no correlate changes in heart rate observed in these rats. We then sought to examine the underlying causes of these blood pressure changes. Balance studies were performed using metabolic cages to examine salt and water intake and output before and during rTBI. Though intake of food and water were slightly affected by rTBI, no measurable effect of rTBI was observed on salt and water balance in these rats. We next measured cardiac function in anesthetized rats following rTBI and found no significant differences in any major contractile variables (LV systolic pressure, dP/tmax, dP/dtmin). In a final series of experiments, we evaluated renal blood flow during step-wise reductions in renal perfusion pressure using an aortic clamp and found that, while blood flow autoregulation was not impaired in rTBI rats, baseline renal blood flow was mildly reduced in injured rats compared to uninjured controls (3.44 ± 0.16 vs 3.94 ± 0.05 mL/min/gKW). In summary, we have generated a rat model of repeated traumatic brain injury that results in a consistent elevation of resting arterial blood pressure. Speculation that these observed changes may result from autonomic dysregulation remains to be investigated. University of Cincinnati College of Medicine Innovation Seed Grant This is the full abstract presented at the American Physiology Summit 2023 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.