bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age‐Related Changes in Macrophage Proliferative Capacity in Response to Chronic Inflammation and Inhaled Ozone
Authors: Liu Ziping , Groves Angela , Golden Thea , Laskin Debra , Gow Andrew 
Published: November 2023

RationaleResident pulmonary macrophages originate from embryonic progenitor cells. In response to injury resident macrophages can be depleted and are replaced from the finite progenitor pool or from blood monocytes. We previously reported that mice lacking surfactant protein‐D (SftpD−/−) display chronic inflammation and are hypersensitive to ozone‐induced lung injury.ObjectiveIn these studies we examined whether constitutive inflammation in SftpD−/− mice results in a loss of the resident progenitor pool, leading to increased recruitment from the vasculature in response to ozone‐induced injury.MethodsC57BL/6J (WT) and SftpD−/− mice (8, 27, and 80 wk) were exposed to air or ozone (0.8 ppm, 3 h)r. After 3 days, lung sections were prepared and stained for Ki‐67 (a marker of proliferative capacity), CD11b and Cd11c (surface markers of pulmonary residency or recruitment) and scored on a scale of 0 to 3.ResultsReduced expression of Ki‐67 was observed in lungs of 80‐week mice relative to 27 and 8 week mice (p<0.05); this effect was greater in SftpD−/− mice which showed upregulation of Ki‐67 at 8 weeks of age. Across all ages Ki‐67 staining was greater in SftpD−/− mice than in WT, although these differences were lowest at 27 weeks. These results correlate with previously observed increases in inflammatory staining in Sftpd−/− mice. A significant interaction between age and ozone responsiveness was noted in SftpD−/− mice. At 8 weeks of age ozone exposure increased Ki‐67 staining, while at 80 weeks of age this response was reversed. Consistently for both Ki‐67 staining and leukocyte infiltration, the 27‐week old mice were the least responsive. Qualitatively, leukocyte recruitment in the SftpD−/− mice resulted in congregation into granuloma‐like structures. The granuloma structures stained positively for Ki‐67 in their center within 8‐week‐old mice, but this expression was lost with age. Spearman correlation for CD11b and CD11c confirmed that proliferating cells within the lung are of pulmonary origin. Of note Ki‐67 staining was not observed in the large foamy cells previously identified in this model as expressing the antioxidant enzyme HO‐1DiscussionThese results support the hypothesis that with age there is a loss of proliferative capacity within the macrophages of the lung in both WT and SPD−/− mice. In the background of chronic inflammation, ozone exposure leads to increased proliferation and activation of resident macrophages in young mice. However, in 80‐week‐old mice ozone exposure results in loss of resident proliferative inflammatory cells and recruitment of acutely activated myeloid cells. This indicates that in the context of inflammation/injury there is a greater reliance on recruited cells. This may represent a significant mechanism within senescence related alterations in pulmonary inflammatory response.Support or Funding Information(NIH HL086621, HL096426, ES004738, AR055073, ES005022)
Mitigation of Hypoxic‐Ischemic Damage in Newborn Rats by Misoprostol, a Prostaglandin E2 Receptor Agonist
Authors: Martens Matthew , Blaney Caitlin , Archiblad Alyssa , Nguyen Lucas , Rampitsch Christof , Gordon Joseph , Ivanco Tammy , Diehl‐Jones William L 
Published: November 2023

Hypoxic‐Ischemic (HI) episodes occur in approximately 50% of preterm infants and result in significant morbidity and mortality. HI activates the nuclear transcription factor HIF1α, which in turn up‐regulates a variety of antioxidant response element‐driven genes including Bnip3, whose protein product has a pivotal role in hypoxia‐induced apoptosis and/or necrosis. Increased Bnip3 expression has been implicated in necrotizing enterocolistis (NEC), an inflammatory bowel disease of premature infants. Previously our laboratory has shown that Misoprostol, a prostaglandin E2 receptor agonist, mitigates the effects of Bnip3 in an enterocyte cell model. We hypothesized that misoprostol regulates intestinal Bnip3 activity in a rat model of HI. Dams and their pups were exposed to environmental hypoxia (10% O2) or normoxia (21% O2) from post‐natal days (PND) 3–10. Experimental animals were injected subcutaneously with 0.1mg/kg Misoprostol each day between PND 3–10, while control animals received saline injections over the same period. PND10 pups were sacrificed, and transverse colon regions were isolated and analyzed for Bnip3 protein expression via western blotting. HI induced a 17‐fold increase in Bnip3 protein expression (p<0.001); in contrast, Misoprostol induced a 72% decrease in protein expression (p<0.05) in hypoxic rats. To explore this effect mechanistically, we examined mitochondrial permeability transition pore (mPTP) opening in HEK293 cells. As expected, Bnip3 transfection increased mPTP opening, whereas Misoprostol inhibited mPTP opening in cells transfected with Bnip3. Furthermore, cotransfection with both Bnip3 and protein kinase A (PKA) mitigated Bnip3‐induced cell death in 3T3 fibroblasts. Finally, we present data showing that PKA phosphorylates Bnip3 protein. We suggest that misoprostol may attenuate hypoxia‐induced cell death via cAMP/PKA signaling pathways.Support or Funding InformationAthabasca UniversityNatural Sciences and Engineering Research Council of CanadaChildren's Hospital Research Institute of Manitoba
A Novel Interaction between Thyroid Receptor Interacting Protein 13 with Tetratricopeptide Repeat Domain 5 Regulates p53 Activity in Murine Inner Medullary Collecting Duct Cells
Authors: Hama Taketsugu , Pressly Jeffrey David , O'Brien Shannon , Park Frank 
Published: November 2023

Renal epithelial cells adapt to biological stressors to maintain their normal biological function. Repair pathways are initiated within the damaged tubular epithelial cells and allow for recovery from the biological stress, whereas more severe injury may circumvent the recovery phase by activating programmed cell death pathways. Emerging evidence has uncovered that thyroid receptor interacting protein 13 (TRIP13) may play a crucial role in the repair process of genomic DNA following damage stimuli. Towards this end, our lab has recently identified increased production of Trip13 transcript levels in renal tubular epithelial cells following acute kidney injury, but there is a paucity of data regarding its mechanism of action in the kidney. In this study we investigated the relationship between TRIP13 and p53, a pivotal transcription factor that acts as a central hub for signal transduction pathways to direct a multifaceted signaling output following biological stress. To investigate the effect of TRIP13 in response to DNA damage, we initially exposed genetic knockdown of TRIP13 in murine inner medullary collecting duct cells to H2O2, which is known to induce double strand breaks. We demonstrated a significant reduction in cell numbers by 40–50% compared to IMCD‐Ctrl and also revealed increased levels of phospho‐p53 (Serine 15) and total p53 following H2O2 insult compared to the IMCD‐Ctrl cells. To further investigate the mechanism by which TRIP13 induces p53 levels and/or activity, we pursued a yeast two‐hybrid screen approach to identify new protein‐protein interactions that could participate in this response. Our yeast two‐hybrid approach identified a protein, tetratricopeptide repeat domain 5 (TTC5), which is known to function as a stress‐inducible transcription p53 cofactor to augment p53 expression, stability and/or activity. Confirmation of a direct interaction between TRIP13 and TTC5 was demonstrated using co‐immunoprecipitation techniques. Moreover, fluorescent microscopy revealed that TRIP13 was largely localized to the cytoplasm with modest signals from the nucleus. In the presence of over‐expressed TTC5, TRIP13 was strongly detected in the nucleus. Western blotting using nuclear fractionation revealed that p53 induction was reduced in overexpression of EGFP‐TRIP13 and myc‐TTC5 compared to control conditions. Thus, our data suggests that TRIP13 interacts with TTC5 to reduce p53 activity following DNA damage.Support or Funding InformationThis study was funded by NIH RO1‐DK90123, and UTHSC seed grant program.
BNIP3 Regulation of Intracellular Calcium
Authors: Field Jared , da Silva Rosa Simone , Mughal Wajihah , Hai Yan , Gordon Joseph , Diehl‐Jones William L 
Published: November 2023

Necrotizing enterocolitis is the most common gastrointestinal emergency affecting low‐birth weight premature infants, with an incidence between 3% and 10% in infants less than 1500 grams, and mortality ranging from 15% to 30%. The pathogenesis of NEC is not clearly defined, but is likely a multifactorial disease wherein intestinal ischemia and hypoxia play fundamental roles. The hypoxia‐inducible death gene Bnip3 has been recently identified as a key regulator of NEC, yet the molecular mechanisms surrounding Bnip3‐induced enterocyte necrosis are not fully defined. Calcium‐mediated opening of the mitochondrial permeability transition pore (mPTP) has been identified as an important precursor event to necrotic cell death. Therefore, we tested the hypothesis that Bnip3 initiates calcium‐dependent PTP opening in cultured cells. We demonstrate that expression of Bnip3 increases mitochondrial calcium content, determined by Rhod2 staining, and that this effect is attenuated by expression of the inhibitory alternative splice variant Bnip3ΔEx3. Consistent with these findings, Bnip3 expression opens the mPTP, which was also prevented by Bnip3ΔEx3. Using organelle‐targeted calcium indicators, we found that Bnip3ΔEx3 did not inhibit Bnip3‐induced calcium release from the endoplasmic reticulum. However, Bnip3ΔEx3 expression re‐directed calcium release and promoted nuclear accumulation of calcium. These novel findings indicate that Bnip3ΔEx3 may protect cells from necrosis by promoting calcium‐dependent signaling pathways that converge on the nucleus, and provide a novel mechanism that may serve to protect enterocytes from hypoxic injury during NEC.Support or Funding InformationAthabasca UniversityChildren's Hospital Research Institute of ManitobaNatural Sciences and Engineering Research Council of Canada
5‐methoxytryptophan Prevents High‐Glucose Induced Mesenchymal Stem cell Senescence through Alteration of Lysosome Mass
Authors: Chang Tzu‐Ching , Shiue Ying‐Chang , Hsu Min‐Fen , Wu Kenneth K. 
Published: November 2023

Bone marrow‐derived mesenchymal stem cells (BMSCs) have great therapeutic potential for many diseases. However, stressful environment may lead BMSCs to premature senescence, resulting in altered cellular characteristics and functions. We had recently reported that high glucose (HG) stress induced BMSC senescence via up‐regulating autophagy. Inhibition of ROS activity with N‐acetylcysteine prevented BMSCs from HG‐induced autophagy and senescence. In this study, we have determined the role of 5‐methoxytryptophan (5‐MTP) on preventing HG‐induced BMSC senescence. 5‐MTP was detected in the conditioned medium (CM) of BMSCs cultured at low glucose (LG) and reduced in CM of cells cultured at HG. Exogenous addition of 5‐MTP reduced p21 and p16 expression in HG‐induced senescent BMSCs. Moreover, 5‐MTP attenuated the activity of senescence associated‐β‐galactocidase (SA‐β‐gal) in HG‐BMSC. Since lysosomes have a crucial role on cellular senescence, we evaluated the effect of 5‐MTP on lysosome by lysotracker staining. Lysotracker‐positive cells were increased in HG‐BMSCs compared to LG‐BMSCs. 5‐MTP addition abrogated lysosome increase in HG‐BMSCs. Our data also revealed that 5‐MTP reduced the glycosylation of LAMP‐1, a membrane protein of lysosome which is involved in lysosome stabilization, in HG‐BMSCs. Like the effects of 5‐MTP, inhibition of LAMP‐1 glycosylation with endoH in HG‐BMSCs attenuated the lysosome mass and SA‐β‐gal activity. Furthermore, both 5‐MTP and endoH could suppress the inflammatory cytokine, IL‐6, secretion from HG‐BMSCs. Taken together, these results indicate that 5‐MTP prevents BMSCs from high glucose‐induced senescence and secretory phenotype, which may be mediated by altering lysosome hemostasis.Support or Funding InformationMOST‐103‐2321‐B‐039‐006
Multisensory Integration in the Developing Brain of the Xenopus laevis Tadpole
Authors: Carrillo Oscar A , Truszkowski Torrey 
Published: November 2023

Perception of meaningful experiences requires that we combine multiple sensory modalities through a process called multisensory integration (MSI). Previous work on the mammalian superior colliculus has revealed the phenomenology of MSI, but little is known about the underlying biophysical mechanisms. In the Xenopus laevis tadpole, a homologue of the superior colliculus, the optic tectum, is directly involved in MSI and is an emerging model for the study of MSI. NMDA receptors (NMDARs) can serve as coincidence detectors in neurons allowing for non‐linear integration of synaptic input, so we hypothesized that NMDARs may play important roles in mediating single‐neuron MSI and, thus, blocking NMDA receptors will stunt MSI in tectal neurons. We also predict that low‐intensity multisensory stimuli undergo greater MSI than high‐intensity multisensory stimuli. We employed multisensory behavioral experiments and electrophysiological recordings to address these questions. Behavioral results indicate that multisensory stimuli not only result in significantly greater startle responses than unisensory stimuli, but that tadpoles use MSI to a greater extent when both stimuli are low‐intensity as compared to one of the stimuli being high‐intensity. Electrophysiology results indicate that low‐intensity multisensory stimuli have greater signal enhancement (5.57 ±1.01) than high‐intensity multisensory stimuli (1.17 ±0.06). Additionally, the low‐intensity multisensory stimuli group has greater MSI (3.18 ±0.68) than the NMDA‐antagonist group (1.34 ±0.34). These preliminary findings suggest that MSI is more useful for enhancing low‐intensity multisensory stimuli and that the NMDA receptor is at least partially involved with MSI on a cellular level.Support or Funding InformationAmerican Physiological Society, National Institute of Neurological Disorders and Stroke
BRIEF ISOCAPNIC HYPEROXIA INCREASES SYMPATHETIC VASCULAR TRANSDUCTION DURING SYMPATHOEXCITATORY MANEUVERS IN HEALTHY HUMANS
Authors: Silva Bruno M. , Machado Alessandro C. , Vianna Lauro C. , Barbosa Thales C. , Prodel Eliza , Fernandes Igor A. , Nobrega Antonio C. 
Published: November 2023

Oxygen supplementation is fundamental in medical care to avoid hypoxia. However, excessive use of oxygen is common in clinical practice, which has been associated with adverse cardiovascular events. Vasoconstriction and, consequently, increase in systemic vascular resistance (SVR) is a clinically relevant side effect of hyperoxia. But interestingly, muscle sympathetic nerve activity (MSNA) does not change or even decreases during hyperoxia. Thus, we hypothesized that hyperoxia increases the ability of muscle sympathetic nerve activity (MSNA) to effect vascular responses (i.e., sympathetic vascular transduction ‐ SPVT), particularly when MSNA is elevated. Healthy young men, aged 18–40 years, were submitted to 3 minutes of rest (n = 6), 3 minutes of post exercise ischemia (PEI; n = 8), and 2 minutes of cold pressor test (CPT; n = 6). Each protocol was conducted in isocapnic normoxia (21% O2; control) and isocapnic hyperoxia (100% O2), in random order. Respiratory rate was controlled using a metronome and tidal volume using verbal feedback to yield similar ventilation between and within protocols. This was done to minimize the influence of ventilation on cardiovascular variables and MSNA. Respiration (metabolic analyzer), hemodynamics (electrocardiogram and finger photoplethysmography), and MSNA (microneurography) were continuously recorded. SPVT was estimated by the ratio between mean values of SVR and MSNA total activity. At rest, hyperoxia did not change cardiac output (CO), SVR, mean arterial pressure (MAP), MSNA total activity, and SPVT. During PEI, hyperoxia decreased CO (Δ −10 ± 3%, mean ± SEM, P = 0.01) and increased SVR (Δ 16 ± 6%, P = 0.03). As a result, MAP did not change. Besides, hyperoxia decreased MSNA total activity (Δ −20 ± 6%, P < 0.01) and increased SPVT (Δ 49 ± 12%, P = 0.05). During CPT, hyperoxia tended to decrease CO (Δ −11 ± 5%, P = 0.08), tended to increase SVR (Δ 18 ± 8%, P = 0.08), and did not change MAP. Moreover, hyperoxia decreased MSNA total activity (Δ −12 ± 10%, P < 0.01) and increased SPVT (Δ 39 ± 11%, P = 0.05). In conclusion, brief isocapnic hyperoxia did not increase SPVT during rest, but increased SPVT during sympathoexcitatory maneuvers in healthy humans.Support or Funding InformationSão Paulo Research Foundation (FAPESP), National Counsel of Technological and Scientific Development (CNPq), and Research Support Foundation of the State of Rio de Janeiro (FAPERJ).
Time Course of Structural and Functional Adaptations of Mesenteric Resistance Vasculature after High Thoracic Spinal Cord Injury
Authors: Popok David , West Christopher , Frias Barbara , Laher Ismail , Krassioukov Andrei 
Published: November 2023

BackgroundSpinal cord injury (SCI) disrupts autonomic pathways and consequently perturbs cardiovascular homeostasis. Injuries above T6 results in loss of descending sympathetic control of the splanchnic vasculature. Blood pressure regulation is impaired resulting in resting hypotension and episodic hypertension, the latter of which is known as a life threatening condition called autonomic dysreflexia (AD). These fluctuations in arterial blood pressure following SCI may also result in dysfunction and maladaptive remodelling at the level of the splanchnic resistance vasculature.ObjectiveTo examine the time course of structural and functional adaptations of resistance mesenteric vasculature in a complete T3 transection rodent model.Design/Method15 male Wistar rats were randomly assigned to three groups: T3 SCI 1 Week (n=5), T3 SCI 1 Month (n=5), and Uninjured Control (n=5). Functional and structural assessment of primary mesenteric arteries were assessed ex vivo using a pressure myograph system. In addition to vessel morphology and myogenic tone, functional assessment of vasocontractility was assessed using α1 adrenoceptor agonist phenylephrine (PE) and methoxamine (MET).ResultsMyogenic tone is significantly impaired in the T3 SCI 1 Week and T3 SCI 1 Month groups compared to the Uninjured Control group (p = 0.0212 and p=0.0059, respectively). EC50 values were extrapolated from PE dose response curves and were lower for both the T3 SCI 1 Week and T3 SCI 1 Month groups compared to the Uninjured Control group (p<0.0001 and p=0.0004, respectively). There are no significant differences found between EC50 values determined for MET. Wall thickness is decreased and vessel diameter is increased in the T3 SCI 1 Month group compared to the Uninjured Control group (p=0.0221 and p=0.066, respectively).ConclusionHypersensitivity to the α1 adrenoceptor agonist PE but not MET suggest deficiency in the reuptake of norepinephrine in resistance mesenteric vasculature. Decreased wall thickness, in addition to an increased vessel diameter may suggest chronic outward hypotrophic remodelling.Support or Funding InformationThis research was funded by the Canadian Institute of Health Research and the Heart and Stroke Foundation of BC and Yukon.
Ca2+ Transients In And Release Of Norepinephrine From Sympathetic Varicosities In Rat Mesenteric Small Arteries – Importance For Force Development
Authors: Aalkjaer Christian , Tarasova Olga , Nilsson Holger 
Published: November 2023

The role of Ca2+ in the sympathetic varicosity in the vascular wall for transmitter release is only inferred from the effect of Ca2+ channel blockers.Here we measured Ca2+ transients directly in nervefibers (confocal microscopy after loading of a Ca2+ sensitive dye into the nerves selectively or into nerves and Schwann cells), norepinephrine (NE) release and in isolated rat mesenteric small arteries.Electrical field stimulation caused a frequency dependent increase of nerve Ca2+, NE release and force development. All three effects were blocked by 100 nM ω‐Conotoxin GVIA and by tetrodotoxin. In arteries where both nerves and Schwann cells were loaded areas where nuclear stain demonstrated the presence of nuclei, field stimulation had little effect on Ca2+, while response to ATP was seen. In contrast ATP had little effect on Ca2+ transients in nerves, where good responses to field stimulation were seen. Acetylcholine (10 μM) caused complete inhibition of field stimulation induced Ca2+ increase, NE release and force development, while 4‐aminopyridine (10 μM) increased all three paramters 2–3 times.It is possible to image Ca2+ in neurons and in Schwann cells in the vascular wall. Acetylcholine induced reduction in NE release is associated with decreased Ca2+ and 4‐AP induced increase of NE release is associated with increased Ca2+ probably mediated by K+ channels belonging to the Kv3 family.Support or Funding InformationDanish Heart Foundation, Danish Research Council, Lundbeck Foundation
Baroreflex Function and Salt Sensitivity Among Normotensives
Authors: Matthews Evan Lee , Coyle Dana E , Brian Michael S , Edwards David G , Stocker Sean D , Farquhar William B 
Published: November 2023

High degrees of salt sensitivity among normotensive individuals increases the risk for cardiovascular disease and death. Salt sensitive rodent models display impaired baroreflex sensitivity, a trait thought to contribute to poor cardiovascular health. Thus, we hypothesized that increased salt sensitivity (SS) in normotensive humans would be associated with decreased cardiac baroreflex sensitivity (CBRS) and decreased high frequency heart rate variability (HF‐HRV). Eighty‐seven healthy normotensive men and women completed 1 week of high (300mmol/day) and 1 week of low (20mmol/day) dietary sodium (random order) with 24hr mean arterial pressure (MAP) assessed on the last day of each diet. The change in 24hr MAP from low to high sodium was used as an index of SS. Of these 87 individuals, 50 agreed to return to the lab for testing under a habitual sodium intake condition. Eight were excluded from this analysis due to the presence of ectopic heart beats. Thus 42 (24 males) are presented in this analysis (age 39±2yrs [range 22–60yrs], BMI 24.3±0.5kg/m2, MAP 83±1mmHg, HR 59±1bpm, habitual urine sodium 93±7mmol/24hr). Electrocardiogram derived R‐R interval and beat‐by‐beat systolic blood pressure (SBP) were measured during 5 minutes of supine rest. Cardiac baroreflex analysis via the sequencing method was used to determine up sequence (concurrent increase in R‐R interval and SBP) and down sequence (concurrent decrease in R‐R interval and SBP) baroreflex sensitivity. Time domain heart rate variability analysis was performed using a fast Fourier transformation focusing on high frequency power. Linear regression analysis between SS and the variables of interest was performed. Among this cohort of normotensive adults, SS was associated with decreased HF‐HRV (r = −0.349, p = 0.046) and tended to be associated with decreased up sequence CBRS (r = −0.309, p = 0.096). However, multiple regression analysis accounting for age revealed that there was no relationship between SS and either HF‐HRV (age adjusted p=0.369) or up sequence CBRS (age adjusted p=0.712). Thus, these data suggest that the relation between increased SS and decreased HF‐HRV and CBRS is largely driven by the association of SS with age.Support or Funding InformationResearch supported by NIH R01 HL104106, & ACSM Foundation Research Grant.