bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loss Of Nicotinamide Nucleotide Transhydrogenase Promotes Redox Dependent Endothelial Activation In Atherosclerosis
Authors: Rao Shashanka , Gautier Nicole , Woolard Matthew , Orr A. Wayne , Krzywanski David 
Published: May 2023

Heart disease is the leading cause of death in the United States and atherosclerosis accounts for nearly 75% of all deaths from heart disease. Atherosclerosis is a chronic inflammatory disease and mitochondrial reactive oxygen species (mtROS) are critical contributors to disease development. Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial protein that maintains mitochondrial NADPH pools and supports the enzymatic degradation of mtROS. Preliminary data indicates that NNT expression is decreased in the endothelium of human atherosclerotic plaques and we sought to test the hypothesis that the loss of NNT increases mtROS and promotes atherosclerosis by enhancing endothelial and vascular dysfunction. Previous we have demonstrated that the loss of NNT was associated with increased vascular ROS production, plaque formation, and plaque size in response to treatment with PCSK9 and high fat diet (HFD). We now show that the loss of NNT in endothelial specific NNT knockout mice promotes enhanced endothelial VCAM-1 expression in response to HFD and disturbed flow. Similarly, in vitro, the loss of NNT promoted both VCAM-1 and ICAM-1 expression in response to oxLDL. Increased adhesion molecule expression associated with the loss of NNT also augmented monocyte adhesion in response to oxLDL consistent with vascular inflammation observed in early atherosclerosis. Additionally, macrophages isolated from NNT knockout mice display enhanced M1 polarization, decreased lipid uptake, and impaired lipid utilization. Co- treatment with the mitochondria targeted antioxidant MitoEbselen is able to normalize both endothelial and macrophage function, underscoring a critical role for mtROS in promoting an inflammatory phenotype in these cells. In both global and endothelial cell specific NNT knockout mice the loss of NNT was associated with increased necrotic core formation in response to PCSK9 treatment and 16 weeks of high fat diet. Taken together, these data indicate that decreased NNT expression promotes endothelial activation, increased inflammatory cell trafficking, macrophage metabolic dysfunction and M1 polarization that could contribute to an acceleration of necrotic core development and severe atherosclerotic disease. NIH P20GM121307. NIH 1 R01 HL145171-01A1 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.
Fibroblast activation protein modulates left ventricular growth and matrix remodeling
Authors: Churillo Amelia , Freeburg Lisa , Samani Stephanie , MacLaren Janna , Saravanan Pranav , Jones Traci , Spinale Francis 
Published: May 2023

Background: Fibroblast Activation Protein (FAP) is abundantly expressed in cancer associated fibroblasts and contributes to activation of proteolytic cascades which alter extracellular matrix (ECM) remodeling. However, whether and to what degree FAP influences left ventricular (LV) function and myocardial structure remains unclear. The present project tested the hypothesis that genetic ablation of FAP would modify LV structure and function in the absence of a pathological stimulus. Methods and Results: Transgenic mice with FAP gene deletion (FAPKO, C57BL/6 background, 3 months of age, n=24) and age matched wild type (WT, n=24) underwent high fidelity LV echocardiography to measure LV ejection fraction, LV end diastolic volume, and LV mass. All results are reported as mean ± SEM. While LV function (62 ± 1 vs. 65 ± 2 %) and volumes (68 ± 4 vs. 70 ± 4 μL) were within normal limits, LV mass to body weight ratio increased (4.9 ± 0.3 vs. 6.1 ± 0.5 mg/g, p<0.05) in the FAPKO mice. LV myocyte cross sectional area (CSA) (168 ± 24 vs. 210 ± 13 μm2, p<0.05) and collagen content (3.3 ± 0.3 vs. 6.1 ± 0.8%, p=0.07) measured by histomorphometry were increased in FAPKO mice. Using rtPCR, increased levels of collagen type I (1.03 ± 0.07 vs. 1.38 ± 0.19 fold change, p<0.05) and type III (1.04 ± 0.08 vs. 1.74 ± 0.26 fold change, p<0.05) were observed in the FAPKO group. Transforming Growth Factor Beta 2 (TGFβ2) (1.04 ± 0.10 vs. 0.74 ± 0.06 fold change, p<0.05) and Snail Family Transcription Repressor 1 (Snai1) (1.11 ± 0.14 vs. 0.77 ± 0.08 fold change, p<0.05) levels were significantly decreased in the FAPKO mice. Conclusion: Increased LV mass and myocyte CSA accompanied by increased collagen content and expression indicated that LV hypertrophy occurred with genetic deletion of FAP. Shifts in the TGF axis and Snai1 suggests that fibroblast endothelial-mesenchymal transition occurred in the absence of FAP. These findings demonstrated for the first time that FAP, most commonly associated with cancer associated fibroblasts, can alter LV myocardial structure. 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.
Deletion of miR-92 and its cluster promotes metabolic and arterial dysfunction, and atherosclerosis
Authors: Gogulamudi Venkateswara , Kim John , Donato Anthony , Lesniewski Lisa 
Published: May 2023

Atherosclerosis, the leading cause of death in the US, is a chronic inflammatory disorder that is associated with arterial dysfunction and hyperlipidemia. Dysfunction of the endothelium, a single layer of cells lining the inside of arteries, is a primary risk factor for atherosclerosis. Endothelial dysfunction is characterized by altered cell metabolism and impaired vasodilation. MicroRNAs (miRs) are small non-coding RNAs that are key regulators of metabolic and cardiovascular diseases. miR-92 has also been shown to be a modulator of endothelial function. We hypothesized that deleting miR-92 would alter endothelial cell metabolism, cause vascular dysfunction, and worsen atherosclerosis. We utilized male and female whole-body miR-92 knockout (miR-92 KO) mice. Hyperlipidemia was induced by administering a single dose of Pcsk9 containing adeno-associated virus, after which mice were fed an atherogenic diet for 16 weeks until aortas were collected to assess atherosclerotic plaque burden. We assessed measures of mitochondrial metabolism in isolated primary endothelial cells (ECs), arterial function, and aortic plaque burden. Using Seahorse technology, we found that primary ECs from miR-92 knockout mice demonstrated a 25% higher rate of oxygen consumption (p<0.02), 25% higher spare respiration (p<0.02), and 61% higher proton leak (p<0.01) compared with wild-type (WT) ECs, indicating increased oxidative phosphorylation. Endothelial-dependent dilation was lower in miR-92 KO mice response to acetylcholine (Ach, 10-9 to 10-4 M) (maximal dilation: 72.2% vs. 38.6%, p<0.001) compared with WT mice, indicative of endothelial dysfunction. miR-92 deletion also increased pulse wave velocity (272.6 vs. 297.2 cm/s, p<0.02), a measure of large artery stiffness. Percent plaque area in the aorta was higher in miR92-deficient mice compared to WT mice (1.0 vs. 2.78%, p<0.03). In conclusion, these findings suggest that deletion of miR-92 and its cluster results in a shift towards oxidative phosphorylation in the endothelium, and this is associated with impaired vascular function and a small, but significant, increase in atherosclerotic plaque development. Together, these results suggest that miR-92 may be a potential therapeutic target to improve arterial dysfunction and reduce atherosclerosis. National Institute on Aging (R01 AG048366 and R01 AG060395) and US Department of Veterans Affairs (I01 BX004492) 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.
Transcriptional repression of the MRTF/SRF-cytoskeleton pathway by Rev-erba promotes beigeing via adipogenic progenitor fate switch
Authors: Xiong Xuekai , Li Weini , Kiperman Tali , Ma Ke 
Published: May 2023

The circadian clock exerts temporal control in metabolic processes to maintain homeostasis, with its disruption leading to the development of obesity and insulin resistance. Adipose fibrosis in obese subjects exacerbates insulin resistance by restricting healthy tissue expansion and remodeling. Rev-erbα is a key circadian clock repressor that displays circadian rhythmic expression in adipose tissue, although its role in adipose tissue fibrosis is not known. Here we show that Rev-ebα inhibits the fibrogenic fate of adipocyte progenitors while promoting beige adipogenic potential via transcription repression of the MRTF/SRF-actin cytoskeleton axis. ChIP-seq analysis of Rev-erbα cistrome in adipogenic precursors identified its transcriptional control of pathways involved in cytoskeleton modulation, including established myofibroblast gene markers small muscle α-actin and Tropomysin. Gain-of-function of Rev-erbα in beige adipogenic precursors markedly suppressed MRTF/SRF activity with enhanced beige differentiation, while Rev-erbα silencing suppressed beige adipogenesis. Prrx1-Cre-mediated subcutaneous beige fat-selective Rev-erbα knock-in induced browning with augmented mitochondrial metabolism, resulting in increased energy expenditure, resistance to obesity and insulin sensitivity. Furthermore, single cell RNA-seq of beige progenitors with Rev-erbα overexpression revealed striking loss of preadipcyte-like (PAL) subpopulations with myofibroblastic characteristics that arise from pericyte lineage. PAL beige progenitors displayed enrichment of epithelial mesenchymal transition-related gene signature and contractile program as compared to preadipocytes. Preadipocyte population with Rev-erbα overexpression exhibited activated oxidative phosphorylation pathway with inhibition of myofibrolast characteristics. Taken together, our findings identify a novel regulatory function of Rev-erbα in modulating adipogenic progenitor fate choice that may promote adipose tissue beigeing while suppressing fibrotic complications. NIDDK grant 1R01DK112794, 1R01DK130499 and AR-DMRI 2023 T2D Innovation 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.
Galanin inhibition of wake-active histaminergic neurons
Authors: Michael Natalie , Khouma Axelle , Caron Alexandre , Plamondon Julie 
Published: May 2023

Histaminergic neurons are a population of wake-active neurons confined to the tuberomammillary nucleus (TMN) in the posterior hypothalamus. They form a crucial component of the ‘sleep switch’ in the brain and promote arousal when activated. The histaminergic neurons are strongly innervated by ventrolateral preoptic area (VLPO) neurons expressing galanin, a neuropeptide associated with sleep promotion. While recent studies have confirmed the importance of VLPO projections to the TMN in initiating and maintaining sleep, the ability of galanin to modulate the activity of the wake-promoting histaminergic neurons of the TMN has largely been overlooked. Therefore, we aimed to determine the mechanisms by which galanin alters the electrical excitability of genetically identified histaminergic neurons. We hypothesized that galanin inhibits histaminergic neuron activity via direct post-synaptic activation of galanin 1 receptors (GalR1). Whole-cell patch-clamp electrophysiology was performed on hypothalamic brain slices from mice expressing tdTomato fluorescence in cells expressing histidine decarboxylase (HDC), the sole enzyme required for histamine synthesis (HDCCre::tdTomato mice). RNAscope® in situ hybridization was used to explore Gal1R mRNA expression in HDC expressing neurons. Whole-cell current-clamp recordings in male mice revealed that galanin (100nM) inhibits the majority of HDC neurons. The galanin-induced inhibition was associated with a hyperpolarization of the membrane potential and a decrease in firing frequency. Consistent with our hypothesis, a selective galanin 2 receptor (Gal2R) agonist (M1145 - 200nM) had no effect on male HDC neuron activity. RNAscope® studies in male mice revealed co-expression of Gal1R mRNA in a large proportion of HDC-expressing neurons. Interestingly, the galanin-induced inhibition of HDC neuron electrical excitability was less pronounced in female mice. Overall, our data point to an important role of post-synaptic Gal1Rs expressed on histaminergic neurons in mediating galanin’s inhibitory effects in the TMN. Our data also suggest that sex differences exist in histaminergic neuron responsiveness to galanin. These findings are consistent with the idea that some of the sleep promoting effects of VLPO neuron activation occur through galanin’s ability to inhibit the wake-active histaminergic neurons. Sleep Research Society (SRS), Canada First Research Excellence Fund (Sentinel North Partnered Research Chair in Sleep Pharmacometabolism), Fondation Institut Universitaire de Cardiologie et de Pneumologie de Quebec (FIUCPQ), Fonds de recherche de Quebec - Sante (FRQS). 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.
Aging Is Associated with a Circulating Endothelial Cell-Derived Microvesicle Phenotype that Impairs Cerebral Fibrinolytic Capacity
Authors: Berry Auburn , Garcia Vinicius , Wegerson Kendra , Cardenas Hannah , Ostrander Emily , Fandl Hannah , Greiner Jared , Stauffer Brian , DeSouza Christopher 
Published: May 2023

Aging is associated with increased risk and prevalence of ischemic stroke. Endothelial cell dysfunction is considered to be a central mechanism underlying the age-related increase in cerebrovascular accidents (CVA). However, the direct, and indirect, effects of aging on endothelial cell biology are diverse and not completely understood. Reduced endogenous fibrinolytic activity is a central etiologic factor underlying ischemic stroke. Endothelial cells are the primary site of synthesis and release of tissue-type plasminogen activator (t-PA), the main plasminogen activator in fibrinolysis and central regulator. Clinical interest in circulating extracellular vesicles, particularly endothelial cell-derived microvesicles (EMVs), has intensified due to their involvement in the development and progression of endothelial dysfunction and CVA. The aim of this study was to determine, in vitro, the effect of circulating EMVs isolated from young and older adults on brain endothelial cell fibrinolytic capacity. We hypothesized that EMVs from older adults would reduce brain endothelial cell t-PA production and release and increase PAI-1 production compared with EMVs from young adults. Twenty-two healthy, non-obese, normotensive, sedentary adults were studied: 10 young (6M/4F; age: 25±1 yr) and 12 older (7M/5F; 64±2 yr). EMV identification (CD144+) and isolation from peripheral blood were performed by flow cytometry. Human cerebral microvascular endothelial cells (hCMECs) were cultured and separately treated with EMVs from each subject. Cultured hCMECs were treated with EMVs in the absence and presence of thrombin (1 unit/mL) for 24 hours. Basal expression of t-PA (25.2±1.5 vs 39.8±1.8 AU) and the t-PA response to thrombin (32.5±1.5 vs 57.2±2.2 AU) were significantly lower (~35%) in hCMECs treated with EMVs from older compared with young adults. Concordant with changes in cell protein expression, basal t-PA production (55.2±3.5 vs 70.1±3.7 ng/mL) and thrombin-stimulated t-PA production (61.9±3.7 vs 88.4±3.8 ng/mL) was significantly lower in cells treated with EMVs from older adults. In conclusion, circulating EMVs may contribute to the increased risk of ischemic stroke with aging by impairing brain endothelial cell fibrinolytic capacity. Diminished capacity of the endothelium to release t-PA is a key mechanistic factor underlying cerebral thrombosis. Nothing to Disclose 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.
Renoprotective and anti-inflammatory effects of growth differentiation factor 15 (GDF15) in mice with diet-induced obesity
Authors: Zheng Hong , Liu Xuefei , Boomer Shane 
Published: May 2023

Growth differentiation factor 15 (GDF15) is a stress-responsive cytokine studied recently for its role in multiple biological processes and diseases. This transforming growth factor beta (TGF-b) family member has been investigated as a therapeutic agent and biomarker for obesity and associated cardiovascular diseases. Studies have shown the anti-inflammation, anti-obesity, and anti-diabetic effects of GDF15, but few have focused on the role of GDF15 in the kidneys. In this study, we hypothesized that GDF15 ameliorates obesity-induced inflammation and fibrosis in the kidney. We treated wild-type (WT) and GDF15 transgenic (NAG) mice with high-fat diets (HFD) (42% calories from fat) or normal chow. Analysis of four groups of mice (WT, WT+HFD, NAG, and NAG+HFD) illustrated significantly reduced levels of kidney fibrosis (a-SMA, TGF-b) and inflammation (NFkB, TNF-a) in the NAG with HFD mice. The kidney injury markers NGAL and TIM-1 were significantly reduced in the NAG+HFD mice. We also found decreased urinary norepinephrine excretion and serum creatinine, and increased glomerular filtration rate, urine volume, and sodium excretion in GDF15 transgenic mice with HFD. Further, in vitro study showed that GDF15 treatment reduced norepinephrine-induced kidney fibrosis and pro-inflammatory cytokine production in cultured kidney HK-2 and LLC cells. These results suggest GDF15 is a possible therapeutic target for kidney injury via its anti-inflammatory and anti-fibrosis protective effects. Funded by NIH R01-DK-114663 & R01-DK-129311 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.
Investigating vitamin D insufficiency in claudin-2 and claudin-12 knockout mice
Authors: Young Kennedi , Alexander R. Todd 
Published: May 2023

Infants and children require a net positive calcium (Ca2+) balance to achieve optimal bone mineral density by early adulthood. Active vitamin D (calcitriol) increases blood Ca2+ levels by increasing intestinal absorption and renal reabsorption of Ca2+ as well as bone remodelling. In both the kidney and intestine, Ca2+ is absorbed both paracellularly, through claudin proteins that make up the tight junction, and transcellularly, through Ca2+ specific transporters and channels. Claudins-2 and -12 are tight junction proteins that mediate Ca2+ permeability across renal and intestinal cell culture epithelial layers. Claudin-2 and claudin-12 double knockout (DKO) mice have a perturbed Ca2+ balance resulting in hypocalcemia, hypercalciuria and decreased bone mineralization. Interestingly, DKO mice did not have increased calcitriol levels or upregulation of Cyp27b1 (the key enzyme regulating serum calcitriol levels), despite a significant increase in serum parathyroid hormone (PTH) levels and decreased serum Ca2+ compared to wild-type mice. We hypothesize therefore that claudin-2 and/or claudin-12 are necessary for optimal PTHR1 signalling to increase Cyp27b1 expression, and thus calcitriol production in the proximal tubule (PT). To address this, we first administered wild-type and double knockout mice calcitriol and found that they could increase their blood calcium levels, though not to the same extent as WT, consistent with the DKO animals not having vitamin D resistance. Next we put wild-type and DKO animals on a low calcium diet. The DKO mice were able to increase their serum calcitriol levels and Cyp27b1 expression under these conditions, consistent with attenuated regulation and not abolition of PTHR1 signalling. Next we examined PTHR1 signaling in HEK-293 cells and a CYP27B1 reporter construct. We found that in HEK cells, PTH treatment results in increased expression of the CYP27B1 promoter construct, and that claudin-2 expression alone, increased promoter expression to the same extent as PTH. Additionally, calcitriol suppressed CYP27B1 promoter expression, however this suppression was abolished when claudin-2, but not claudin-12, was expressed. In primary mouse proximal tubule cells, PTH significantly increased Cyp27b1 mRNA expression compared to controls. In future experiments we will investigate the effects of claudin-2 and/or claudin-12 on PTH-induced Cyp27b1 mRNA expression using primary proximal tubule cells from claudin-2, claudin-12 or claudin-2/12 DKO mice. This work will tease out the role of the proximal tubule tight junction proteins claudin-2 and -12 in regulating calcitriol levels. Funding: Alberta Innovates, NSERC and CIHR 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.