bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolutionary Variation and Biomechanics of the Avian Furcula
Authors: Sullivan Samuel Patrick , Middleton Kevin M. , Holliday Casey M. 
Published: April 2020

The avian wishbone, or furcula, serves as the cranial‐most attachment of the m. pectoralis in most birds, variably connects to the coracoid and sternum, and is morphologically diverse across the clade. Furcula shape and microstructure covary with flight style, suggesting its functional importance to flight. Several overlapping hypotheses have been proposed for furcular morphology, such as aiding wing protraction or increasing ventilation efficiency, but the bone remains an enigmatic part of the avian pectoral girdle. In particular, we have little understanding of how furcula morphology and material properties relates to other pectoral structures, including flight muscles such as m. sternocoracoideus. Despite the hypothesized significance of the furcula in the origin of flight and diversification of flight styles, further work needs to be done to understand its functional properties among extant taxa.In order to explore variation in the furcula and pectoral structures relative to flight style, we studied members of 12 bird families using a three‐pronged approach. Specifically, we examined 1) the shape of the furcula in relation to its in situ orientation using non‐contrast computed tomography (CT), 2) the relative size of m. pectoralis and its subdivisions using contrast‐enhanced CT (DiceCT), and 3) the functional potential of the m. sternocoracoideus to effect or respond to furcula deformation using muscle lever analysis, material properties testing, and muscle spindle histology.We found substantial differences in furcular orientation, muscular proportions, and furcula material properties across the sample. Whereas earlier studies found a relatively weak correlation between flight style and furcula shape, we found that accounting for in situ furcula orientation improves the correlation between shape and flight style. Birds with more anteriorly‐curved furculae also show a relatively larger cranial division of m. pectoralis. These results support the hypothesis that furcula curvature mediates the protractive capability of m. pectoralis during downstroke. Notably, muscular differences between furculate and afurculate species of parrots (Psittaciformes) were insignificant despite similar flight styles, suggesting that other musculoskeletal structures may take on the functional role of the furcula in certain clades. We also found little variation in m. sternocoracoideus regarding spindle density and muscle moments about the coracosternal joint. The small size and suboptimal location of m. sternocoracoideus suggests that it serves a proprioceptive role, perhaps necessary to assess interglenoid distance during flight, rather than to laterally spread the furcula via the coracoids. Nevertheless, its morphological disparity across our sample remains unexplained.Support or Funding InformationUniversity of Missouri Life Sciences Fellowship
The ErbB3 receptor tyrosine kinase regulates expression of Notch target genes and intestinal stem cell markers.
Authors: Hsieh Jonathan J. , Almohazey Dana , Frey Mark R. 
Published: April 2020

BackgroundStem cell‐driven regeneration of the intestinal epithelium is important for recovery of damage from insults including inflammation, chemotherapy, and radiation. This process is controlled through tight regulation of intestinal stem cells (ISCs). Our lab has previously reported that intestine‐specific knockout of the receptor tyrosine kinase ErbB3 leads to precocious development of Paneth cells and increased Paneth cell numbers in mice the mouse intestinal epithelium. Since Paneth cells can play a supportive role for ISCs, we tested the hypothesis that altered ErbB3 signaling results in changes in the ISC compartment.MethodsWe crossed ErbB3flox/flox mice with mice expressing villin promoter‐driven Cre to generate an intestinal epithelial‐specific ErbB3 knockout mouse model (ErbB3‐IEKO). Ileal samples were collected from these mice, fixed, and embedded in paraffin for immunostaining. Tissue samples from the ileum were also processed for RNA and protein for qPCR and immunoblots. Samples were probed for Notch target genes and Notch ligands due to the importance of Notch signaling in maintaining the intestinal stem cell compartment. Enteroids were generated from ileum of C57Bl/6 mice and treated with the ErbB3 ligand Nrg‐1β. To activate and inactivate Notch experimentally, enteroids and HT29 cells were treated with valproic acid (VPA) and the γ‐secretase inhibitor DAPT respectively.ResultsqPCR of ErbB3‐IEKO ileum showed increased expression of Lgr5 (rapid‐cycling ISCs) and Bmi1 (facultative ISCs or secretory progenitors capable of regenerating ISCs). Ileal sections also showed increased numbers of Lgr5+ cells by in situ hybridization, and western blots showed increased protein levels of Bmi1 in ErbB3‐IEKO ileum. qPCR of ErbB3‐IEKO ileum showed increased expression of Notch target genes Hey1, Hey2, and Heyl, as well as expression of Notch ligands Dll1, Jag1, and Jag2. Enteroids treated with Nrg‐1β had decreased expression of Hey1, Lgr5, and Bmi1. Enteroids and HT29 cells treated with VPA to activate Notch had decreased expression of ErbB3 RNA; this was abrogated by DAPT treatment.ConclusionErbB3 negatively regulates expression of Lgr5 and Bmi1, markers for fast‐cycling and quiescent ISCs, respectively, indicating a possible role for ErbB3 in the ISC niche. Furthermore, ErbB3 and Notch appear to negatively regulate one another, suggesting a possible mechanism for ErbB3’s effects on ISCs and intestinal cell differentiation.Support or Funding InformationThis work was supported by NIH award R01DK095004.
Cellular Fractionation Identifies the N‐ and C‐ Termini Contributions Toward Membrane Association of the Rho GTPase TCL
Authors: Erickson Jeffery A. , Esoe Dave-Preston I. , Tader Brooke R. , Hamann Michael J. 
Published: April 2020

TCL is a poorly characterized Rho‐family GTPase; however, our lab has performed detailed structure/function analysis of TCL to gain insight into its cellular biochemistry. We have found that its unique N‐terminal extension promotes GTP‐loading of TCL and plasma membrane localization. Deletion of this TCL‐specific sequence promotes localization of TCL to intracellular vesicles. To further explore the role of the N‐terminal and C‐terminal sequences on TCL localization, plasmids encoding Venus were manipulated to include amino acids 1–24 of TCL at the N‐terminus of Venus and amino acids 198–214 at the C‐terminus of Venus. Additional N‐ and C‐terminus deletion mutants of YFP‐tagged TCL were also produced. These plasmids have been transfected into HeLa cells, and subcellular localization of the expressed proteins assessed by fluorescence microscopy and a fractionation procedure. Our results show a clear role for the C‐ terminus of TCL in facilitating membrane localization, but no significant localization directly related to the N‐terminus. Defining how TCL localizes to different cellular membrane environments will help us to understand more clearly its role focal adhesion dynamics, as well as how these dynamics may relate to melanoma development and tumor‐associated angiogenesis.Support or Funding InformationThis work was supported by Bemidji State University Biology Department and the College of Business, Mathematics, and Science. Support was also provided through the Neilson Foundation, Bemidji, MN and Regenerative Medicine Minnesota (RMM‐2017‐EP‐04).
The ciliary localized GPCR, MCHR1, modulates odor responses in the olfactory bulb
Authors: McIntyre Jeremy C. , Jasson Kalene , Ross Jordan , Fletcher Max , Reed Randy 
Published: April 2020

The sense of smell is essential for maintaining full human health and quality of life. It plays an important role in the detection of environmental dangers as well guiding decisions such as what foods to eat. However, olfactory processing is influenced by the physiological state of an organism. Physiological changes such can be integrated in the hypothalamus, through populations of neurons expressing various neuropeptides. One of these peptides is melanin‐concentrating hormone (MCH) which functions in both promoting feeding and sleep. Neurons expressing MCH project to several areas of the brain including the olfactory bulb (OB), where the MCH receptor, MCHR1, a g‐protein coupled receptor, is expressed. MCH signaling has been implicated in olfactory driven behaviors, however the mechanism by which it does so is unknown. In rodents, there is a single MCH receptor, MCHR1, which is enriched in neuronal primary cilia. To better understand the mechanism by which MCHR1 signaling affects olfactory behaviors we have first analyzed its distribution in the OB. Using antibody labeling, we find that MCHR1 localizes to cilia of interneurons in the granule cell and glomerular layers. To further confirm this, and generate a potential tool for future studies, we used CRISPR/CAS9 to fuse mCherry to the n‐terminus of MCHR1 (mCherry:MCHR1). Expression of mCherry:MCHR1 matches that of endogenous MCHR1, localizing to the primary cilium of granule cells and a subset of periglomerular cells. MCHR1, and mCherry:MCHR1, is not detected in the primary cilia of mitral cells, the primary output neurons of the olfactory bulb. To test the neuromodulatory role of MCHR1 in olfactory signaling, we have performed functional imaging experiments of the OB in response to odorant stimulation. Using epifluorescence calcium imaging, we find that glomerular responses of mitral/tufted cells are enhanced following administration of an MCHR1 antagonist, SNAP‐94847, (t(157) = 5.425, p <0.0001) while application of MCH decreases glomerular responses (t(99) = 10.98, p <0.0001). Together these data suggest that the ciliary GPCR, MCHR1 contributes to modulation of olfactory function. Furthermore, our newly generated mouse line will aid in studying the role of MCHR1 in other brain regions and will aid in determining the importance of ciliary localization of specific GPCRs in modulating neuronal function.Support or Funding InformationSupport was provided by R00DC013555 and pilot grans from the University of Florida Center for Smell and Taste, and a UF MBI pilot project (JCM), T32DC015994 (KRJ) F31DC 016485 (JMR) and R01DC004553 (RRR)
Mathematical Modeling of Lymph Flow in a network of Lymphatic Vessels
Authors: Dabiri Yaghoub , Lu Xiao , Guo Xiaomei , Patel Bhavesh , Kassab Ghassan 
Published: April 2020

IntroductionLymphatic system is an important part of the circulation system. Assessment of alterations in lymphatic flow in diseased conditions could lead to better treatment strategies. In vivo determination of the flow and pressure in the lymphatic vessels can be challenging. Computational modeling can be used to simulate the lymph flow in silico. The goal of this study was to develop a platform whereby the lymphatic flow in a network of vessels can be simulated. The mathematical model was based on animal experiments.MethodsWe conducted swine experiments whereby the connections between lymphatic vessels in the hind limb were visualized. The length and dimeter of the vessels were also determined from animal experiments. Finite element (FE) method was used to discretize one dimensional lymph flow equations. The lymph vessels were considered as extensible cylinders where the relation between pressure drop and flow was based on experimental data. Also, for valves, the relation between pressure drop and flow was based on experimental data. At junctions we assumed pressure drop is negligible and the flow in the proximal vessel is equal to the sum of flow in distal vessels. The inflow velocities at the distal vessels and the pressure at the proximal vessel were used as boundary conditions. We conducted a time‐dependent analysis where the initial conditions were obtained from a steady state solution.Results and DiscussionWhen number of the elements and time steps were increased the solution converged. For a steady‐state rigid vessel, the results were in agreement with the Poiseuille's law. Also, for a branch with rigid vessels the results were in agreement with analytical solutions. For models with extensible vessels, the computed pressure and velocities corresponded to the experimental data. The platform was applicable to junctions with different number of vessels. Because the dimension of lymphatic vessels is noticeably small, measurement of diameters, flow and pressure is challenging, which limits the data that can be fed to the numerical model. As a future direction, this platform could be used to predict flow characteristics in different disease conditions, and possibility to perform more efficient amputations.ConclusionComputational modeling was utilized to simulate flow and pressure in lymphatic vessels. There are limitations in measurements of flow characteristics in the lymphatic vessels. Our computational framework could be used to better understanding of lymphatic system functionality in health and disease, and to simulate outcomes which are difficult to determine experimentally.Support or Funding InformationThis work was supported by the Office of the Assistant Secretary of Defense for Health Affairs, through the Defense Medical Research and Development Program under Award No. W81XWH‐19‐1‐0087. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Department of Defense
Metabolic Alterations in Cardiomyocytes are Associated with Methamphetamine‐Induced Cardiomyopathy
Authors: Von Lotten Mallory , Abdullah Chowdhury S. , Aishwarya Richa , Alam Shafiul , Morshed Mahboob , Remex Naznin Sultana , Orr A. Wayne , Goeders Nicholas E. , Kevil Christopher G. , Hartman Brandon , King Judy A. , Traylor James , Bhuiyan Md. Shenuarin 
Published: April 2020

IntroductionIllicit use of Methamphetamine (METH) in humans is associated with cardiac dysfunction known as METH‐induced cardiomyopathy. Specifically, the stimulant inhibits mitochondrial bioenergetics, resulting in energy deprivation, which may ultimately lead to the activation of the adaptive autophagy process.ObjectivesWe aim to determine the METH‐induced metabolic alterations in cardiomyocytes leading to the development of the METH‐associated cardiomyopathy.Methods and ResultsAutopsy heart samples from humans with a positive toxicology for METH use showed substantial fibrosis in the heart. ‘Binge’ METH‐administration in mice for four weeks developed cardiac hypertrophy and fibrosis in the heart. Mitochondria isolated from the METH‐treated heart showed defects in mitochondrial respiration. Western blot analysis of autophagy regulatory protein expression ‘Binge’ METH‐treated mice showed increased expression of LC3B‐II and p62 proteins. To determine the direct non‐catecholamine dependent effect of METH on cardiomyocytes, we treated primary cardiomyocytes with different doses of METH (100 and 250 μM). Western Blot analysis showed a dose and time‐dependent increase in the expression of LC3B‐II and autophagy‐related protein 7 (Atg7). We also observed increased phosphorylation of cellular metabolism‐related proteins, i.e., phosphorylated FOXO1 (at Ser 256) and FOXO3a (at Ser 253). We conducted autophagy flux assay to confirm the METH‐induced activation of autophagy exposing cardiomyocytes with METH (250 μM for 24 hours) followed by treatment with lysosomal inhibitor BafilomycinA1 (50nM for 3 hours). Western Blot analysis showed increased expression of LC3B‐II in BafA1 treated cardiomyocytes suggesting activation of autophagy following METH‐exposure.ConclusionsWe report that METH use causes adverse fibrotic remodeling in hearts from both human and pre‐clinical mouse model. We found that METH suppresses mitochondrial respiration in cardiomyocytes that elicit adaptive activation of autophagy and autophagy regulatory proteins as a response to METH‐induced energy deprivation.Support or Funding InformationThis project was performed as part of the CURIOUS program supported by grant R25HL147665 from the NIH/NHLBI. This work was further supported by NIH/NHLBI grants R00 HL122354, R01HL145753, R01HL145753‐01S1 and PGM121307A to Dr. Bhuiyan. American Heart Association postdoctoral fellowship to Dr. Alam; Malcolm Fiest post‐ and pre‐doctoral fellowships to Dr. Abdullah and Aishwarya by CCDS, LSUHSC‐S.
Understanding fundamental aspects of respiratory control in dystrophin‐deficient mice
Authors: Burns David P. 
Published: April 2020

Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease associated with respiratory‐related morbidity and mortality. DMD is characterised by severe skeletal muscle weakness, which extends to the striated muscles of breathing. Our recent research has explored deficits and compensation in the respiratory control network governing respiratory homeostasis in a pre‐clinical model of DMD, the mdx mouse. Deficits at multiple sites of the network provide considerable challenges to respiratory control, including carotid body hypo‐activity (sensory deficit) and diaphragm dysfunction (
Burns et al., 2017). Despite profound diaphragm weakness and lower muscle activation during maximum non‐ventilatory efforts, inspiratory pressure‐generating capacity is preserved in young adult mdx mice, revealing compensation in support of respiratory system performance that is adequate, at least early in dystrophic disease (
Burns et al., 2019). Our findings point to a considerable reserve in the capacity of the respiratory neuromuscular system to perform a broad range of function, resulting from the recruitment of auxiliary muscles in support of peak respiratory‐related performance. We propose that a progressive loss of compensation during advancing disease, combined with diaphragm dysfunction, underpins the development of respiratory morbidity in dystrophic diseases. Studies utilising anti‐inflammatory, anti‐stress and anti‐oxidant pharmacotherapy strategies indicate that interventions aimed at preserving muscle fibre complement and promoting muscle fibre quality in mdx respiratory muscles can alleviate breathing and muscle functional deficits (
Burns et al. 2018). Dr. Burns will discuss current knowledge gaps and the need to better appreciate fundamental aspects of respiratory control in pre‐clinical models so as to better inform intervention strategies in human DMD.Support or Funding InformationDepartment of Physiology, University College Cork and The Physiological Society.
Effect of Cerebral Blood Flow on Cognition across Healthy Adulthood
Authors: Shoemaker Leena N. , Wilson Luke C. , Lucas Samuel J.E. , Machado Liana , Walker Robert J. , Cotter James D. 
Published: April 2020

Both cognitive function and cerebral blood flow (CBF) decline across the lifespan. However, the relation between them remains unclear, particularly in the context of aging. Furthermore, fitness improves both cognition and CBF, and may be associated with preserved cognitive and cerebrovascular function in an older population.PurposeThe aims of this study were to 1) clarify the effect of CBF on cognition across healthy adulthood, and the extent to which age‐related reductions are modulated by the usually‐observed impairment in cerebrovascular function, and 2) examine the association of aerobic fitness on baseline CBF and cognitive performance in healthy young and older adults.MethodUsing a placebo‐controlled, single‐blinded, randomized cross‐over design, we tested the hypothesis that an acute reduction in CBF (using indomethacin [1.2 mg/kg oral dose]) would impair cognition in both young (n = 13; 25 ± 4y) and older (n = 12; 58 ± 6y) adults. Cerebrovascular function was assessed using blood velocity in the middle cerebral artery (MCAv; Transcranial Doppler Ultrasound). Cerebrovascular CO2 reactivity (CVRCO2) was calculated as the change in MCAv for a given change in end‐tidal CO2 (mm Hg). Cognitive function was measured using visuomotor, inhibitory, and mental switching response time tasks. Aerobic fitness was predicted using a submaximal exercise test (i.e., V̇O2peak). Linear and rank‐based mixed models were used to assess the individual and interactive effects of cerebrovascular function and cognition, while accounting for age, sex, and aerobic fitness.ResultsOlder adults had 11% lower MCAv and 15% worse response time overall (all p ≤ 0.049), but not reliably lower CVRCO2 (p ≥ 0.16). Indomethacin decreased MCAv by 26 ± 11% and CVRCO2 by 69 ± 25% (all p < 0.01), regardless of age. The degree of indomethacin‐induced reductions in CVRCO2 was strongly associated with baseline CVRCO2 (r = 0.87, p < 0.01). Visuomotor response time was 6 ± 13% slower after indomethacin (p = 0.04), but this impairment was not linearly associated with decreases of MCAv (r = −0.26). Finally, aerobic fitness was not associated with baseline CBF in either group (r ≤ 0.14), and was only weakly associated with response time performance in young (r ≤ −0.34), but not older (r ≤ 0.21) adults.ConclusionThe impairments in cognitive function from indomethacin were not evidently associated with the 26% reduction in cerebral perfusion, even in older adults. Compared to young, older adults had worse cognitive performance and decreased CBF but did not have impaired cerebrovascular function. Aerobic fitness was only weakly associated with resting CBF and cognition in both young and older adults. Therefore, cognitive performance may not be influenced by a ≤26% reduction in CBF per se in healthy young and older adults.Support or Funding InformationFunding support from the School of Physical Education, Sport and Exercise Sciences, and Department of Medicine.
Actigraphic Measures of Sleep and White Matter Volume in a Bi‐Racial Cohort
Authors: Hossain Sharmin , Gamaldo Alyssa , Shiroma Eric J. , Katzel Leslie I. , Davatzikos Christos , Erus Guray , Gullapalli Rao P. , Seliger Stephen L. , Evans Michele K. , Zonderman Alan B. , Waldstein Shari R. 
Published: April 2020

ObjectivesAbout 50% of adults report some form of sleep disturbance with deleterious impact on cerebral white matter (WM). Here, we investigated interactive relations of sleep duration or quality and race on cerebral WM volumes in a largely middle‐aged, bi‐racial cohort.MethodsThe cross‐sectional Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) Scan study yielded 119 stroke and dementia‐free participants (mean age ~51y; 37% African American; ~48% women) with complete actigraphy, magnetic resonance imaging (MRI), and covariate data. A triaxial accelerometer (ActiGraph GT3X+, ActiGraph Corp) worn on the wrists for up to seven consecutive days, provided measures of total sleep time (TST), sleep efficiency (SE), and wake after sleep onset (WASO). Self‐rated sleep quality was assessed via the Pittsburgh Sleep Quality Index (PSQI). Brain MRI, acquired by 3.0 Tesla scanner, yielded quantitative measures of average WM volumes for total brain, total lesion, frontal, occipital, temporal, and parietal lobes. Multivariable linear regression analyzed interactive relations of each sleep variable and race to WM outcomes: model 1‐adjusted for age, sex, and race; model 2‐model 1+ body mass index, smoking, alcohol use, and depressive symptoms. Results are expressed as regression coefficients (β), p‐value.ResultsFollowing adjustments, TST*race interactions were noted for total (17.15, <0.05), frontal (13.17, <0.05), and parietal (7.77, <0.05) WM volumes. Shorter sleep duration was related to lower volumes in African Americans but greater volumes in Whites. PSQI*race interactions for total (59.62, <0.01), frontal (40.07, <0.01) and parietal (17.84, <0.05) WM showed relations of poorer sleep quality to lesser WM volumes in African Americans only.ConclusionShorter sleep duration and lesser self‐reported sleep quality were related to lower total and regional WM volumes among African Americans. The mechanisms underlying these racial differences warrant further investigation and may help explain neuropsychological health disparities.Support or Funding InformationSupported by National Institutes of Health grants ZIA‐AG000195 (MKE), R01‐AG034161 (SRW), and the University of Maryland Claude D. Pepper Older Americans Independence Center (P30 AG028747).