bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification and Characterization of Bacterial and Host Factors Involved in Microtubule Disassembly in Epithelial Cells during Edwardsiella Infections
Authors: Aggarwal Priyanka , Wang Qiyao , Liu Qin , Leung Ka Yin , Guttman Julian Andrew 
Published: November 2023

Enteric bacteria from the genus Edwardsiella cause great losses to a variety of commercially important fish such as the Japanese Eel, Channel Catfish and Turbot. In humans, they cause a gastroenteritis‐like phenotype. These bacteria are known to infect both inflammatory and epithelial cells. Although macrophages are by far the best‐studied cell types during these infections, epithelial cell studies have lagged primarily due to poor infection models. Because these bacteria resemble other intestinal pathogens and because the host cytoskeleton is a common target of intestinal pathogens, we hypothesized that similar infections could be established to evaluate host actin, intermediate filament and microtubule alterations. Here we established two different epithelial cell infections using HeLa and CaCo‐2 cells and demonstrate that only the microtubule cytoskeleton is noticeably altered by these bacteria. We found that microtubules are initially severed then completely disassembled during Edwardsiella infections. To identify the bacterial and host components involved in this phenotype, we screened a 2,758 mutant Edwardsiella genome transposon insertion library and localized all known host microtubule‐severing enzymes (katanin, spastin, and fidgetin). Using the screening approach we were able to narrow the 2,758 Edwardsiella mutants/genes to 15 that are key players in causing MT disassembly in epithelial cells. Immunolocalization experiments showed the katanin subunit A‐like 1, katanin subunit B 1, and katanin subunit B‐like 1 at microtubule cut sites, suggesting their involvement in the microtubule disassembly event. This work not only provides the first evidence of host cytoskeletal alterations during Edwardsiella infections, but also provides a resource for further characterization of molecular components involved in microtubule disassembly in general.Support or Funding InformationFunding source: Natural Sciences and Engineering Research Council of Canada (NSERC)and SFU BISC department funds
Palladin Can Compensate for Arp2/3 Complex Defects and Structurally Organizes Actin‐Rich Structures Generated during Listeria monocytogenes Infections
Authors: Dhanda Aaron S , Vogl A Wayne , Otey Carol A , Beck Moriah R , Guttman Julian A 
Published: November 2023

The actin cytoskeleton is co‐opted by the invasive and motile bacteria Listeria monocytogenes (Listeria) for their entry, intracellular motility and dissemination from one cell to another. Once inside host cells, these bacteria are propelled by bacterially‐generated, Arp2/3‐based, actin‐rich structures called comet tails. The host protein palladin is a crucial actin crosslinker of motile actin‐based structures generated during eukaryotic cell motility. Recently, palladin has been shown to nucleate branched actin filament arrays in vitro. Whether this new actin‐nucleating role of palladin is involved in powering cell motility remains unknown. Here we set out to test the hypothesis that palladin is a crucial component of bacterially‐induced actin‐rich structures generated during Listeria infections and simultaneously used Listeria as a model to uncover new physiological functions of palladin. Through immunofluorescence microscopy we initially identified palladin at sites of bacterial entry and at motile comet tails. Infections of epithelial cells depleted of palladin through RNAi revealed that palladin was dispensable for bacterial invasion. However, when comet tails were examined, we found that they were significantly shorter and severely misshapen in the absence of palladin. Furthermore, when palladin mutants defective for actin or VASP binding were overexpressed, comet tails either disintegrated at their distal ends or became progressively thinner as they moved, suggesting that palladin is a crucial organizer of the actin arrays within comet tails. Using electron microscopy, we further demonstrated that comet tail thinning resulted in switching of the actin network from branched actin arrays to parallel actin bundles. Finally, to determine if palladin's actin‐nucleating function could compensate for the Arp2/3 complex during comet tail motility, we overexpressed palladin in cells treated with the Arp2/3 inhibitor CK‐666. Remarkably, in the presence of CK‐666, Listeria could initiate and maintain comet tail motility in palladin overexpressing cells, whereas Listeria motility immediately ceased in cells with endogenous levels of palladin. Taken together we show that palladin is essential for normal comet tail function as well as morphology, and when overexpressed, can compensate for Arp2/3 complex functional defects during bacterial actin‐based motility.Support or Funding InformationGrant Funding Source: NSERC (grant no. 355316 to J.A.G and grant no. 155397‐2013 to A.W.V), NIH and SFU departmental funds
IP3R, TRPM6 and Homer1 are Localized to ER‐PM Contact Sites at Tubulobulbar Complexes in Rat Testis
Authors: Adams Arlo , Vogl A. Wayne 
Published: November 2023

The seminiferous epithelium is the site of spermatogenesis; the cellular basis for male fertility. Large junction complexes between Sertoli cells act to control the movement of differentiating spermatogenic cells while those between Sertoli cells and late spermatids connect these late spermatids to the apex of the epithelium. During spermatogenesis, turnover of these junction complexes must occur so that the next generation of spermatogenic cells can move into the epithelium, and mature spermatozoa can be released into the seminiferous tubules. Structures called Tubulobulbar Complexes (TBCs) have been implicated in junction turnover due to their appearance during turnover and their necessity in allowing sperm release. TBCs likely drive the internalization of junction complexes but how Sertoli cells control the development and degradation of TBCs is unknown. TBC regulation may be a product of a well‐known yet functionally unestablished contact site between TBC bulbs and cisternae of ER. Because calcium exchange occurs at other ER‐plasma membrane contact sites such as those between ER and endosomes, we chose to probe for the IP3R calcium channel. Using bioinformatics, we found potential protein binding partners for IP3R in the form of the TRPM6 plasma membrane calcium channel and the homer1 scaffolding protein. Using a high‐resolution pre‐embedding immunoelectron microscopy technique we localized all three proteins to the TBC‐ER contact site. This data suggests the potential for scaffolding of IP3R to TRPM6 via homer1 at TBC‐ER contacts and opens up the possibility for calcium exchange as an important function of the ER at these sites.Support or Funding InformationSupported by a NSERC Discovery Grant (#155397‐2013) to AWV
Cadherin‐6B Proteolysis Controls The Neural Crest Cell Epithelial‐to‐Mesenchymal Transition Through Transcriptional Regulation
Authors: Taneyhill Lisa 
Published: November 2023

During epithelial‐to‐mesenchymal transitions (EMTs), cells disassemble cadherin‐based adherens junctions to segregate from the epithelia. Chick premigratory cranial neural crest cells reduce Cadherin‐6B (Cad6B) levels through several mechanisms, including proteolysis, to permit their EMT and migration. Serial processing of Cad6B by ADAMs and γ‐secretase generates an intracellular C‐terminal fragment (CTF2) that could acquire additional functions independent of full‐length Cad6B. Here we report that Cad6B CTF2 possesses a novel pro‐EMT role by up‐regulating EMT effector genes in vivo. Following proteolysis, CTF2 remains associated with β‐catenin, which stabilizes and redistributes both proteins to the cytosol and nucleus, leading to an increase in β‐catenin, CyclinD1, Snail2, and Snail2 promoter‐based GFP expression in vivo. A CTF2 β‐catenin‐binding mutant, however, fails to alter gene expression, indicating that CTF2 modulates β‐catenin‐responsive EMT effector genes. Notably, CTF2 associates with the endogenous Snail2 promoter in the cranial neural crest, providing, for the first time, evidence that a cadherin CTF2 can bind to chromatin in vivo. Furthermore, this association with chromatin is dependent upon an intact β‐catenin‐binding domain within CTF2. Collectively, our data reveal how Cad6B proteolysis orchestrates multiple pro‐EMT regulatory inputs, including a reduction in adhesion within the premigratory neural crest cell population and up‐regulation of the Cad6B repressor Snail2, to ensure proper cranial neural crest cell EMT and appropriate patterning of the vertebrate embryo.Support or Funding InformationThis work was supported by NIH grants R01DE024217 and F32DE022990 and a Research Scholar Grant, RSG‐15‐023‐01‐CSM, from the American Cancer Society.
Investigating UBA1 distribution and its relevance to Spinal Muscular Atrophy
Authors: Maani Amr , Shorrock Hannah , Gillingwater Tom 
Published: November 2023

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by the degeneration of lower motor neurons. SMA is the most common genetic cause of infant mortality and is caused by a homozygous deletion of the Survival Motor Neuron 1 gene (SMN1). There is currently no effective therapy. However, experiments on animal models targeting UBA1 pathways have shown improvements in neuromuscular phenotype. Studies have shown that there is a reduction of UBA1 in SMA and that mutations in UBA1 can cause X‐linked SMA. Nevertheless, the mechanism by which UBA1 mediates degeneration in SMA is unclear. This project investigated the role of UBA1 in SMA and, more specifically, the relevance of sub‐cellular UBA1 distribution in SMA. UBA1 distribution in post‐mitotic cells, including cultured primary neurons, was studied to identify whether UBA1 distribution is disrupted in cell models of SMA. UBA1 distribution was also studied in HEK293 cells to confirm the distribution in dividing cells. This study confirmed that UBA1 distribution changes over time in cultured motor neurons and that there is a reduction of nuclear UBA1 in SMA motor neurons. Results suggest that understanding UBA1 distribution in SMA will be essential to future studies in reaching a therapeutic cure.Support or Funding InformationThe University of Edinburgh
Changes in the extracellular matrix following ischemic stroke in the rat
Authors: Patel Monal , McClain Allison , Meyer Alice , Andrews Ellen 
Published: November 2023

Ischemic strokes results in immediate inflammation and neuronal cell death. The amount of functional recovery that is seen following a central nervous system (CNS) injury is limited. Recent studies have shown that chondroitin sulfate proteoglycans (CSPGs) contribute to the lack of functional plasticity due to their inhibition of neurite outgrowth. Previous research indicates that there is limited neuroplasticity (neurite outgrowth) from the uninjured contralateral hemisphere and this neuroplasticity can be enhanced with various therapeutic treatments (anti‐nogo, adult human bone marrow stem cells, etc.). Astrocytes and microglia are involved in the post‐ischemic inflammatory response, and contribute to the changing extracellular matrix (ECM) by both producing CSPGs and producing enzymes that can alter CSPGs and the ECM in the ischemic core and penumbra region. Alterations to CSPG expression, the ECM and the glial response may be altered in the contralateral sensorimotor cortex to allow for the limited neuroplasticity seen after injury. In the present study, we investigated glial activation and CSPG expression in the sensorimotor cortex after an ischemic stroke in the rat, both ipsilateral and contralateral to the lesion 3, 7, 14 and 28 days post stroke. Both neurocan expression and GFAP expression increased at 14 days in the ipsilateral sensorimotor cortex. Total neurocan expression is significantly increased 14 days post stroke in the ipsilateral sensorimotor cortex as compared to control. GFAP expression (indicative of activated astrocytes) is significantly increased in the sensorimotor cortex surrounding the lesion at 14 days post stroke as compared to control. Both aggrecan and CD11b (microglia) expression are stable at 3 and 14 days post stroke as compared to controls. Western blot analysis of CSPG expression at 7 days and 28 days post injury is under investigation. CSPG distribution at all time points (3 day, 7 day, 14 day, 28 days post injury) is being analyzed via immunohistochemistry.These results may help pinpoint the best time and location of treatment to help restore function following an ischemic stroke.Support or Funding InformationSupported by Midwestern University
Therapeutic effects of long‐term systemic adipose‐derived stem cell conditioned medium in a mouse model of amyotrophic lateral sclerosis
Authors: Walker Chandler L. , Kennedy Felicia M. , Fry Colin M. E. , Iyer Abhirami K. , Du Yansheng , March Keith , Jones Kathryn J. 
Published: November 2023

Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disease involving motor neuron (MN) loss, muscle paralysis and death. The gold standard animal model of ALS, the superoxide dismutase 1 (SOD1) transgenic mouse model exhibits similar clinical progression through pre‐symptomatic, symptomatic, and end stages of disease. Disease onset occurs pre‐symptomatically by 47 days of age in SOD1G93A mutant mice. Prior research revealed initial hindlimb muscle denervation, with progressive neuromuscular junction (NMJ) loss over time. Our previous data indicate systemic daily therapy of adipose‐derived stem cell conditioned medium (ASC‐CM), beginning at symptom onset, delayed onset and symptom progression and extended survival in SOD1G93A mice, suggesting a central mechanism of action. In addition, we observed that daily ASC‐CM therapy starting at 35 days of age, when NMJ innervation resembles non‐diseased mice, significantly attenuated NMJ loss by day 47 in SOD1G93A mice. We then hypothesized that long‐term systemic ASC‐CM therapy could potentially provide enhanced functional and survival benefits through both peripheral and central mechanisms compared to post‐symptom onset therapy. To test this hypothesis, sixteen SOD1G93A and sixteen wild‐type (WT) mice received either systemic daily ASC‐CM or vehicle control medium beginning at 35 days of age until day 63, followed by a twice‐weekly treatment regimen until animal end stage. Starting at 63 days of age, we performed a battery of behavioral assessments testing gait, grip endurance, tail elevation, and rearing, among other behaviors, to identify any therapeutic effects on symptom onset and progression. At end stage, NMJ innervation of the medial gastrocnemius muscle and lumbar motor neuron survival will be assessed. Though the study is still underway, initial analyses have identified possible functional benefits of long‐term ASC‐CM therapy. Based on our previous pre‐symptomatic and symptomatic treatment data, we predict that systemic ASC‐CM therapy may prevent hindlimb muscle denervation and act centrally to ameliorate functional decline and impart survival benefits in the SOD1G93A ALS mouse model.Support or Funding InformationNIH T32 HL79995 (CLW); IU Collaborative Research Grant 2214076 (KJJ & KM)
DNA methylation and mRNA expression in the dmPFC are altered after protracted withdrawal from cocaine self‐administration
Authors: Ploense Kyle , Vieira Philip , Kippin Tod 
Published: November 2023

Cocaine addiction is a chronic disorder that involves excessive, uncontrolled drug consumption. Both humans and rodents will escalate the amount of cocaine taken when it is readily available indicating that excessive intake is dependent on prior consumption. In rodents, however, escalation is not observed when access is restricted to “limited” (i.e. 1 hr) daily sessions. Here, we investigated whether control over drug intake or drug exposure are the critical factors in escalation by employing a mixed limited‐contingent exposure and prolonged noncontingent exposure model. . Rats were implanted with a permanent jugular catheter and then allowed to lever press to self‐administer (FI20 with a 20 s light cue paired with each infusion) saline vehicle (0.1 ml/infusion) or cocaine (0.25 mg/infusion) under 3 conditions: limited‐access (1 h/ day), extended‐access (6 h/day), and 1 h limited‐access + 5 h non‐contingent exposure (via yoking to extended access rats) to cocaine. Based on the first 10 min and first hour of daily access, we observed rapid escalation of cocaine intake in both the extended‐access and limited‐access + non‐contingent conditions (ps < 0.05). We also observed a delayed escalation of cocaine intake in the limited‐access condition within the first 10 min of self‐administration (p < 0.05), but not across the 1 h of cocaine availability. Interestingly, escalation of cocaine intake was accelerated in the limited + non‐contingent‐access condition relative to the extended‐access condition. However, relative to the other cocaine conditions, the limited‐access + non‐contingent group exhibited markedly more non‐reinforced responses indicating that distinct behavioral mechanisms drive escalation by contingent versus noncontingent drug exposure (ps<0.05). Additionally, post‐mortem quantification of homer2 (a gene implicated in cocaine intake and associated) mRNA expression within the dmPFC indicated elevation only in the extended‐access conditions (p<0.05). Rises in homer2 mRNA were associated with distinct levels of DNA methylation, hydroxymethylation, and transcription factor binding to the Homer2 gene. Together, these findings indicate that either contingent or non‐contingent “excessive” cocaine exposure supports escalation but have differential effects on the temporal patterning of operant responsiveness as well as molecular correlates of escalation.Support or Funding InformationThis research was supported by NIH grants DA‐027115 and DA‐027525 (TEK) and DA024038 (KKS), as well as funding from and the W.M. Keck Foundation (TEK)
Different expression of miRNA in the elderly with cognitive impairment and control group in aluminum exposed mining area
Authors: Ma Huina , Huang Hehua , Tang Lingling , Zhou Shanjin , Chen Bingpu , Ling Yanwu 
Published: November 2023

Alzheimer's disease (AD) is a nerve degenerative disease, it's intimately connected with the genetic and environmental factors. Previous work showed high aluminum exposure may be a risk factor of AD in the mining area. The dysregulation of miRNA expression has been found to be closely associated with AD. Cognitive function was measured by mini‐mental state examination(MMSE). The contents of trace elements (Al) in blood were determined using ICP‐AES. We analyzed the expression of miRNAs in peripheral blood of a total of 360 Cognitive impairment group (n=156) and healthy controls (n=204) by quantitative reverse transcriptase polymerase chain reaction (qRT‐PCR). Data assays show 7 miRNAs displayed significantly different expression levels in Cognitive impairment group serum compared with controls in aluminum mining area. Indicate that deregulated miRNAs in blood might be used as biomarkers in the diagnosis of early AD or other dementia disease.Support or Funding InformationSupported by National Natural Science Foundation of ChinaNO.31560294
Motor neuron scaling and somatic growth in normal and transgenic rainbow trout, Oncorhynchus mykiss
Authors: Anderson Curt W , Feurborn Ethan T , Bradley Terence M , Rodnick Kenneth J 
Published: November 2023

Teleost fishes demonstrate indeterminate growth and a dramatic increase in body mass over their life cycle. Myotonal muscle mass comprises >60% of the adult body mass in active species and effective growth and development of functional capability requires interactions between multuinucleated muscle fibers (myocytes) and motor neurons. Basically, as all organisms grow and develops, the nervous system must compensate for the change in size. While numerous studies have examined myogenesis, muscle fiber recruitment and hypertrophy, and phenotypic plasticity in fishes, our understanding of the myocyte/neuron linkage during development is extremely limited. The goal of this project is to determine how motor neurons in rainbow trout change through development and how this change can be viewed through principles of scaling. Sections of spinal cord were removed at the rostral, medial, and caudal positions from normal and genetically modified rainbow trout to overexpress follistatin, which antagonizes myostatin and increases myotonal muscle. Increased muscling in these transgenic trout is due primarily to myocyte hyperplasia. Spinal cords (n= 35) were sectioned on a microtome and stained with acridine orange. Sections were analyzed to 1) measure the cross sectional area of the spinal cord and ventral horn motor neurons and 2) determine how motor neurons develop to compensate for growth in total muscle mass. The average motor neuron area from normal rainbow trout revealed an unusual allometric relationship compared to endothermic animals. As the mass of the fish increased there was a positive (r2 = 0.961) correlation to the motor neuron area. Compared with normal rainbow trout, transgenic trout had an average neuron area similar to that of the normal trout, but relative to per gram of body mass motor neuron is significantly less, suggesting that the motor unit size – the number of skeletal muscle fibers per motor neuron ‐ increases with an increase in muscle mass. Previous studies suggest that neuron size in endothermic organisms follow a pattern of metabolic allometric scaling, yet motor neuron from ectotherms in this study had scaling coefficient of just 0.204. These findings suggest that as the axial muscle increases mass in normal and transgenic rainbow trout, the peripheral nervous system is not undergoing a similar growth in neuron size.Support or Funding InformationNIH Grant #P20 RR0116454
Swine Barn Dust Exposure Activates Microglia through Induction of Oxidative Stress and the Resultant Neuroinflammation Appears to Involve HMGB1 and RAGE Signaling
Authors: Massey Nyzil , Puttachary Sreekanth , Mahadev‐Bhat Sanjana , Shrestha Denusha , Kanthasamy Anumantha G , Charavaryamath Chandrashekhar 
Published: November 2023

Large swine farms employ full time workers who are exposed to occupational contaminants including organic dust, LPS, peptidoglycan and gases. Exposed workers mainly report bronchitis, asthma and loss of lung function. Most studies have focused on mechanisms of inflammation underlying respiratory symptoms. But effect of a continued exposure to swine barn dust on other vital organs such as brain have not been studied. Brain microglial cells are similar to macrophages of other organs in immune activation. Therefore, we tested a hypothesis that swine barn dust extract (SBDE) activates microglial cells of the brain.Settled dust from commercial swine operations was collected, buffer extract prepared and filter sterilized. Mouse microglial cell line (C57BL6) were treated with SBDE or lipolysachharide (LPS) or peptidoglycan (PGN) or medium and stained for the expression of, Iba1, gp91 phox (reactive oxygen species indicator), HMGB1 (high‐mobility group box‐1), RAGE (receptor for advanced glycation end products) and DAPI at 0, 6, 12, 24 and 48 h post treatment.Microglia morphologically appeared reactive with an upregulation gp91 phox by 24 hours post PGN or SBDE treatment. At 48 hours, SBDE treated microglia demonstrated translocation of nuclear HMGB1 into the cytoplasm. RAGE (transmembrane) was co‐localized with cytoplasmic HMGB1 in SBDE treated microglia.All these findings demonstrate that swine barn dust exposure can cause activation of microglia and induce oxidative stress. The resultant neuroinflammation appears to involve HMGB1 and RAGE signaling.Support or Funding InformationIowa State University, Ames, IA