bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free fatty acid exacerbates diabetic kidney injury by suppressing autophagy-lysosomal function via ER stress
Authors: Zhao Xueying , George Jasmine 
Published: May 2023

Diabetic kidney disease (DKD), the leading cause of chronic kidney disease, is characterized by accumulation of renal tubule free fatty acids (FFAs) and triglyceride (TG)-enriched lipid droplets (LDs) and cell death. The present study aimed to investigate how FFA or TG induces renal tubular cell apoptosis, thereby contributing to the progression of DKD. Cell studies were conducted to define the causal role and underlying mechanism of FFA-activated ER stress and organelle dysfunction in tubular cell injury. Six-week-old wild-type (WT) and eNOS-deficient C57BL/6J mice were placed on normal diet (ND, 5% fat calories) or high-fat diet (HFD, 42% fat calories) for two weeks, and then rendered diabetic with alloxan. Alloxan injection resulted in equivalent hyperglycemia in ND and HFD-fed WT and eNOS-deficient mice. However, a massive increase in urinary albumin was observed in HFD plus alloxan-treated eNOS-deficient mice, which was accompanied by excessive accumulation of neutral lipids in damaged proximal tubules. Moreover, in the diabetic eNOS-deficient kidneys, HFD feeding resulted in suppression of autophagy-lysosomal function and increase in tubular cell apoptosis. Cell studies revealed that saturated FFA palmitate but not unsaturated oleate induced eukaryotic initiation factor (eIF)2α phosphorylation, and then stimulated the activating transcription factor (ATF)4 and C/EBP homologous protein (CHOP), which, in turn, impaired autophagy-lysosomal function, leading to cell apoptosis. In addition, we observed a dramatic upregulation of LD-associated protein ADRP expression and TG-enriched LD formation in oleate-treated renal tubular cells, which was not apparent in palmitate-treated ones. Together, this study demonstrates that accumulation of renal FFA, rather than TG, plays a crucial role in the pathogenesis of diabetic kidney injury by suppressing autophagy-lysosomal function through ER stress signaling. This work was supported by the National Institutes of Health Grants SC1DK112151 and S21MD000101. 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.
Macrophage-specific EphB2 Deficiency Mitigates Nonalcoholic Steatohepatitis-fibrosis in Mice
Authors: Kamdem Donald Severin , Egal Erika , Pellizzari Sarah , Pham Tuam , Evason Kimberley , Boudina Sihem , Henkemeyer Mark , Beaudin Anna , Mimche Patrice 
Published: May 2023

Background & Aims: Emerging evidence suggests that the receptor tyrosine kinase EphB2 regulates tissue inflammation and fibrosis. However, its contribution to non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD or NASH) remains largely unknown; thus, we aimed to determine its role. Methods: In NAFLD/NASH patients, hepatic EphB2 and serum EphrinB2 ligands were evaluated. Disease phenotyping was performed in male and female wild type (WT), EphB2-/-, EphB2-kinase-dead (EphB2K661R), EphB2-kinase-overactive (EphB2F620D) mice, and in macrophage-specific EphB2-/- mice fed the obesogenic Gubra-Amylin NASH diet for 22-28 weeks and the Choline Deficient Amino-acid improved high-fat diets for 10-12 weeks. The role of EphB2 in inflammation was investigated in bone marrow-derived macrophages. Pharmacological inhibition of EphB2 for the treatment of NASH was also evaluated in vivo. Histology, hydroxyproline assay, flow cytometry, gene expression, biochemical assays, and RNA sequencing were used to dissect the molecular mechanism underlying macrophages’ EphB2 function in NASH. Results: Hepatic EphB2 was strongly upregulated in NASH patients and correlated with NASH fibrosis score. Serum EphrinB2 was also elevated in NASH patients. In mouse models of NASH, EphB2-/- mice showed a significant reduction in liver steatosis, inflammation, and fibrosis compared to WT mice. This is supported by a significant reduction of liver fat content, pro-inflammatory and fibrotic genes in EphB2-/- compared to WT mice. EphB2 forward signaling is likely the main driver of NASH progression as depicted by the significant increase in steatosis, inflammation, and fibrosis observed in EphB2F620D compared to WT and EphB2K661R mice. Flow cytometry revealed a reduced macrophage population in EphB2-/- mice compared to WT mice.In addition, bone marrow-derived macrophages from EphB2-/- mice showed reduced inflammation when stimulated with LPS in vitro. Interestingly, macrophage-specific EphB2-/- showed a reduction of NASH fibrosis and associated metabolic syndrome. Conclusions: We have identified EphB2 as a key player in the pathogenesis of fatty liver disease in humans and mice and its therapeutic targeting could potentially mitigate NASH fibrosis and associated metabolic syndrome National Institutes of Health (NIH) 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 mitochondrial PKD on right ventricular fibrosis under pulmonary hypertension
Authors: Nieto Bridget , O-Uchi Jin , Cypress Michael , Landherr Maria , Chaput Isabel , Polina Iuliia , Suckow Mark , Jhun Bong Sook 
Published: May 2023

Introduction: Growing evidence suggests a link between right ventricular (RV) fibrosis, poor function of the pressure-overloaded RV, and mortality in pulmonary arterial hypertension (PAH). However, there are no currently available therapies that specifically target RV fibrosis. Using RV tissues from a preclinical rat PAH model, we previously reported that activation of stress-responsive protein kinase D (PKD) and phosphorylation of its substrate dynamin-related protein 1 (DRP1) occur specifically at the outer mitochondrial membrane (OMM) of RV cardiac fibroblasts (RV-CFs), but not in RV myocytes. RV-CFs isolated from PAH rats exhibited increased mitochondrial fission, mitochondrial reactive oxygen species (mROS), and proliferative signaling compared to RV-CFs from control animals, suggesting an association between PKD signaling in RV-CFs and RV fibrosis. Hypothesis: Inhibition of mitochondrial PKD signaling in CFs can attenuate RV fibrosis in PAH. Methods: Primary adult CFs from human ventricles were used for in vitro assays. A preclinical rat PAH model (Sugen 5416 injection and 3-week hypoxia followed by 4-week normoxia) was used for in vivo assays. Results: To specifically inhibit PKD activity at the OMM, an OMM-targeted dominant-negative PKD1 (mt-PKD-DN) was generated by adding an OMM-target sequence (amino acid 1-33 from human TOM20) at the N-terminus of PKD1-K612W. We confirmed that mt-PKD-DN is specifically expressed in mitochondria and decreases basal PKD activity only in mitochondria, assessed by protein fractionation. Importantly, mt-PKD-DN was able to inhibit mitochondrial fission, reduce mROS, hyperpolarize mitochondrial membrane potential, and ultimately decrease CF proliferation in vitro. To inhibit mitochondrial PKD activity in quiescent and resident CFs in vivo, we next administrated CF-selective adeno-associated virus serotype 9 (AAV9) carrying human TCF21 (hTCF21) promoter and mt-PKD-DN into the rat PAH model by tail vein injection. Introduction of AAV9-hTCF21-mt-PKD-DN or its control virus did not significantly alter baseline cardiac function. CF-specific mt-PKD-DN expression was able to significantly reduce RV hypertrophy/fibrosis, and RV-CF hyperproliferation as assessed by immunostaining of a nucleus-localized marker of active cell proliferation Ki67. Lastly, we found the partial recovery of in vivo RV function (i.e., recovery of tricuspid annular plane systolic excursion in echocardiography) in PAH rats with mt-PKD-DN. Conclusion: Targeting mitochondrial PKD may be a potential therapeutic strategy to reduce cardiac fibrosis under pathological conditions including PAH. R01HL136757 (to J.O.-U), AHA 18CDA34110091 (to B.S.J) 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.
Caveolin-3 Nitrative Modification: A Novel Mechanism of Cardiac Insulin Resistance in Pre-Diabetic Animals
Authors: Wang Yajing , Zhao Jianli , Meng Zhijun , Zhang Zhen , Liu Caihong , Gao Erhe , Lopez Bernard , Christopher Theodore , Koch Walter , Ma Xinliang 
Published: May 2023

Rationale: Diabetes-induced myocardial insulin resistance leads to cardiac injury. There is, however, no consensus on the underlying molecular mechanisms. Studies have demonstrated that diabetic hearts are resistant to other cardioprotective interventions, such as adiponectin and preconditioning. In the face of multiple therapeutic interventions, the “universal” resistance suggests the impairment of the requisite molecule(s) involved in broad pro-survival signaling cascades. Caveolin (Cav) sits on cellular membrane and coordinates transmembrane signaling. It remains unknown whether Cav3 contributes to diabetic ischemic heart failure (HF) and impaired cardiac protective signaling. Methods and Results: Mice were fed a normal diet (ND) or high-fat diet (HFD) for 2-12 weeks and subjected to myocardial ischemia and reperfusion. At four weeks of HFD feeding (pre-diabetes), insulin's cardioprotective effect was significantly blunted compared with the ND group, when insulin signaling molecules were unchanged. However, Cav3/IRβ complex formation, a prerequisite for insulin transmembrane signaling, was significantly reduced. Cav3 tyrosine nitration is prominent in the pre-diabetic heart among various post-translational modifications altering protein/protein interaction. By nitrating cardiomyocytes with SIN-1, signalsome complexes are reduced and insulin transmembrane signalling is blocked. It was determined that Cav3 nitrates at Tyr73 using mass spectrometry. A phenylalanine substitution of Tyr73 (Cav3Y73F) abolished SIN-1 induced Cav3 nitration, restored the Cav3/IRβ complex, and rescued insulin transmembrane signaling. Furthermore, cardiomyocyte-specific Cav3Y73F reexpression blocked HFD-induced Cav3 nitration, preserved Cav3 signalsome integrity, restored transmembrane signaling, and restored insulin's protective effect against ischemic HF in mice. As a result of diabetic nitrative modification at Tyr73 of Cav3, the formation of Cav3/AdipoR1 complexes and the function of adiponectin for cardioprotection are also reduced. Conclusion: In pre-diabetic hearts, nitration of Cav3 at Tyr73 leads to signal complex dissociation that leads to cardiac insulin/adiponectin resistance, contributing to the progression of ischemic heart failure. Developing early interventions geared toward preserving Cav3-centered signalsome integrity may prove effective against diabetic exacerbation of ischemic heart failure. there is no disclosure 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.
Reduction in Arterial Stiffness Is Related to Exercise Intensity
Authors: Lima Natalia , Lima Natalia , Jackson Ronald , Sherman Sara , Hibner Brooks , Fernhall Bo , Baynard Tracy , Clifford Philip 
Published: May 2023

Increased arterial stiffness is associated with cardiovascular risk and mortality. Central and peripheral arterial stiffness measured with pulse wave velocity (PWV) are known to be reduced 5 min after a single bout of dynamic exercise using a large muscle mass. The effect of small muscle mass rhythmic handgrip exercise on peripheral stiffness is unknown. In addition, it is not known whether the magnitude of reduction in peripheral arterial stiffness is related to the intensity of exercise. We hypothesized that a higher exercise intensity would result in a larger reduction in post-exercise peripheral arterial stiffness. Eight healthy young volunteers participated in this study (5 females, 28 ± 4 yrs, mean ± SD). Two Millar tonometers were placed simultaneously on the brachial and radial arteries of the exercising arm for measurement of peripheral arterial stiffness. Beat-by-beat arterial pressure was obtained by a photoplethysmographic sensor on the middle finger of the contralateral hand. Brachial-radial PWV and mean arterial pressure (MAP) were recorded before exercise then at 5-, 15-, and 30-min post-exercise. The exercise consisted of two 5-min bouts of rhythmic handgrip exercise (2sec contraction/2sec relaxation) at either 30% or 50% of their maximal voluntary contraction (MVC) performed in randomized order. Baseline brachial-radial PWV before handgrip exercise at 30% MVC was 10.7 ± 2.8 m/sec. Postexercise at 30% MVC, PWV was 9.6±2.6 m/sec at 5min, 9.8 ± 2.7 m/sec at 15min, and 11.5 ± 2.9 m/sec at 30 min (all p>0.05 compared to baseline). Before handgrip exercise at 50% MVC baseline brachial-radial PWV was 13.1 ± 3.2 m/sec. Post-exercise at 50% MVC, PWV was 9.9 ± 3.7 m/sec at 5min (p<0.05), 9.1 ± 2 m/sec at 15min (p<0.05), and 10.2 ± 3 m/sec at 30 min (p>0.05). MAP was not statistically significantly different across all time points (p > 0.05). These results show that peripheral arterial stiffness measured as brachial-radial PWV was reduced after 5-min and 15 min of rhythmic handgrip exercise at 50% MVC, but not at 30% MVC. Thus, the magnitude of reduction in PWV was related to the intensity of exercise. The observed reduction of brachial-radial PWV was not a function of changes in blood pressure which would have confounded the PWV results. This study is the first to show that small muscle mass handgrip exercise reduces peripheral PWV. 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 caspase-1 and AIM2 inflammasome in ischemia/reperfusion injury of myocardium
Authors: Senger Nathalia , Vieira-Junior Denival , Mota Joice , Marinho Claudio , Barreto-Chaves Maria Luiza 
Published: May 2023

Acute myocardial infarction induces a sterile inflammatory response, leading to cardiomyocyte damage and adverse cardiac remodeling. The contribution of inflammasomes has been involved to the cardiac remodeling, however, little is known about its potential role in cardiac hypoxia, especially the AIM2 inflammasome. Thus, the present study aimed to investigate the impact of AIM2-inflammasome absence in the myocardial susceptibility to ischemia/reperfusion (I/R) injury. For this purpose, 3-month-old male mice knockout mice for caspase-1 ( casp-/-) or AIM2 ( aim2 -/-) were used (n=5). Cardiac injury was induced in isolated heart using the ex vivo Langendorff perfusion model (20 minutes of global ischemia and 45 minutes of reperfusion). All protocols were approved by the Ethics Committee on Animal Experimentation of ICB-USP (n05402181121). Casp-/- and aim2 -/- mice showed no significant differences in heart weight to tibia length ratio when compared to wild-type mice ( WT). Supporting these results, the cardiomyocyte area, evaluated on histological slides stained with WGA (wheat germ agglutinin), was similar in all groups. In relation to functional data, post-ischemic recovery of cardiac function was similar between aim2 -/- and WT mice. However, casp-/- mice showed worse recovery after I/R, as evidenced by decreased left ventricular developed pressure (LVDP) (mmHg) and increased resistance in ventricular relaxation (TAU index). In conclusion, we provide evidences that caspase-1 is involved in myocardial susceptibility to ischemia/reperfusion (I/R) injury. Additional experiments are being conducted to increase the number of animals and to evaluate other parameters as cardiomyocyte death. FAPESP (grants number: 2019/17031-2 and 2022/0084-0). 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.
Relation between left ventricular relaxation and post-transcriptional regulation with exercise in pigs
Authors: Samani Stephanie , Freeburg Lisa , Barlow Shayne , Jones Traci , Sarzynski Mark , Zile Michael , Shazly Tarek , Spinale Francis 
Published: May 2023

Background: Regular exercise has been shown to induce physiological adaptations such as improved left ventricle (LV) function, but LV diastolic function, particularly LV chamber stiffness (LV Kc) is rarely examined. In addition, the relation between changes in LV function, particularly LV Kc with regular exercise and post-transcriptional regulator checkpoints, the microRNAs (miRs), remains unexplored. This project tested the hypothesis that an exercise protocol in pigs will cause a shift in miR profiles which would affect pathways relevant to LV Kc. Methods and Results: Pigs (n=9; 3 months) underwent a chronic treadmill protocol (4 weeks, 10° elevation, 2.5 mph, 10 minutes) and two-dimensional speckle-tracking echocardiography was performed to obtain LV ejection fraction (LV EF) and to compute LV Kc. Age and weight matched non-exercised pigs (n=6) served as referent controls. All results are reported as mean ± SEM. LV EF increased with exercise (66.7 ± 1.9 vs 82.0 ± 0.7 %, p≤0.05) whereas LV Kc fell by approximately 50% (0.56 ± 0.04 vs 0.27 ± 0.02 kPa, p≤0.05). Using an 84 miR array (rt-PCR), a total of 34 (40%) miRs changed with exercise whereas 8 miRs (miR-19a, miR-22, miR-30e, miR-99a, miR-142, miR-144, miR-199a, and miR-497) correlated to LV Kc (r= 0.543, r=0.646, r=0.671, r=0.638, r=0.814, r=0.613, r=0.575, r=0.726 respectively, p≤0.05). Specifically, these miRs mapped to functional domains relevant to LV Kc such as calcium handling/active relaxation and extracellular matrix remodeling (i.e. metallopeptidases, heparin sulfate proteoglycans, and transforming growth factor-beta). Conclusion: Chronic exercise in pigs reduced LV chamber stiffness and correlated to miRs that mapped to regulatory processes which likely contributed to this reduction. Thus, utilization of miR profiling may provide insight into exercise training effectiveness. This work was supported in part by National Institutes of Health grant R01HL130972-01A1 (F.G.S.) & R01HL5949 (F.G.S.) as well as a Merit Award from the Veterans Health Administration, BX000168-10A1 (F.G.S.) & BX005320 (F.G.S.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. 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.
CCL5 signaling is associated with impaired vascular function with age
Authors: Velusamy Prema , Grotle Ann-Katrin , Skow Rachel , Fadel Paul , Trott Daniel 
Published: May 2023

Aging is the most important and predictable risk factor for cardiovascular diseases, the major hallmarks of which are hypertension, arterial stiffness and impaired endothelial function. CCL5, a chemokine also called RANTES (Regulated upon Activation, Normal T-cell Expressed and Presumably Secreted) is expressed in T-cells and monocytes. Immune cells have been implicated in arterial inflammation and dysfunction with advancing age. More importantly T-cell activation has been known to contribute to endothelial dysfunction and large artery stiffness in rodent models of acute hypertension. In these rodent studies CCL5 mediates T-cell accumulation around the arteries. The T-box transcription factor, Eomes is the master regulator of CD8 effector and memory T-cells and plays a critical role in T-cell immune response. We previously reported that these effector CD8 cells accumulate in the aorta and mesenteric vasculature in older mice. However, whether CCL5 signaling and T-cell Eomes are associated with arterial dysfunction in older humans is unknown. Therefore, we tested the hypothesis that CCL5 signaling is associated with age related declines in vascular function. We measured plasma CCL5 in a cohort of 9 healthy young (age: 27 ± 4 years; 6 males) and 11 older individuals (age: 60 ± 9 years; 3 males). We also measured CCR5 in T-cells isolated from whole blood using flow cytometry in a subset of healthy young (n=3) and older (n=5) subjects. Endothelial function was assessed as brachial artery flow-mediated dilation (FMD; %) using duplex Doppler ultrasound. We observed that plasma CCL5 (Young: 2632.5 ± 318.5, Older: 4191.1 ± 537.87 pg/mL, p=0.0303) was significantly elevated in the aged individuals when compared to young controls. There was a strong negative correlation between plasma CCL5 levels and FMD (R2=0.5446; p=0.0040). From the flow cytometry data, we found that CD8 cells from older adults exhibited greater Eomes protein content compared to young controls (young: 2699 ± 488.08, older: 14616 ± 5104.17 MFI, p=0.0198). A large proportion of Eomeshi cells were also CCR5 positive (young: 28.65 ± 2.16, older: 46.5 ± 8.83 %, p=0.0357), suggesting that in addition to memory differentiation, Eomes may play a role in CCL5 signaling with age. These preliminary results provide evidence that CCL5 signaling, which mediates T-cell recruitment to the artery with age in animal models, is also upregulated in older adults and associated with reduced endothelial function. Further studies are warranted to delineate the mechanisms by which T-cells influence arterial function during aging in humans. This work is supported by grants from NIH K01AG061271, R01AG060395, AHA940023 (DWT) and R01 HL-127071 (PJF) 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.