bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atg16L1 Knockout Induces Insulin Resistance through Proteasomal IRS1 Degradation, Mediated by the Induction of ER Stress
Authors: Frendo‐Cumbo Scott , Jaldin‐Fincati Javier , Brumell John H. , Klip Amira 
Published: June 2021

Insulin resistance is a defining feature of type 2 diabetes, yet our understanding of the progression and development of insulin resistance is incomplete. Recently, deficient autophagy, a bulk degradation pathway, was associated with the induction of insulin resistance, although the causative mechanism remains unknown. We sought to investigate the underlying signals responsible for how deficient autophagy induces insulin resistance. We report that knockout of an essential autophagy protein, Autophagy Related 16L1 (Atg16L1), in mouse embryonic fibroblasts (MEFs) markedly decreases insulin and insulin‐like growth factor 1 (IGF1)‐stimulated Akt recruitment to the cellular membrane and phosphorylation on S473 and T308, as well as cortical actin remodelling. Atg16L1 KO did not adversely affect insulin receptor (IR) or IGF1 receptor content, cell surface IR localization or 125I‐insulin binding. However, Atg16L1 KO MEFs and Atg16L1 depleted HeLa cells displayed reduced protein content of Insulin Receptor Substrates (IRS1 and IRS2), pivotal proximal signals in insulin signaling known to be dysregulated in insulin resistant and diabetic states. Corroborating these findings, visceral adipose tissue of high fat‐fed mice displayed lower Atg16L1 mRNA and IRS1 protein content. Expression of IRS1myc recovered insulin‐stimulated Akt phosphorylation in KO MEFs. Treatment of KO MEFs with the proteasome inhibitor MG132restored IRS1 protein content and insulin‐stimulated Akt phosphorylation. Moreover, ER stress, which induces insulin resistance at the level of IRS1, was upregulated in Atg16L1 KO MEFs. Alleviating ER stress with the chemical chaperone phenylbutyrate increased IRS1 protein expression and insulin stimulated Akt phosphorylation similar to MG132. Together, we show that Atg16L1 KO induces insulin and IGF1 resistance through the induction of ER stress, leading to targeted proteasomal degradation of IRS1.Support or Funding InformationS.F.C was supported by an NSERC Alexander Graham Bell Canada Graduate Scholarship‐Doctoral (CGS D), as well as Restracomp and a 2018 Pricewaterhouse Coopers Student Bursary from the Hospital for Sick Children.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Human Craniofacial Spliceosomopathies
Authors: Bernier Francois 
Published: June 2021

Germline mutation of core components of the spliceosomes have been associated with a range of clinical disorders from isolated retinitis pigmentosa (RP) to developmental syndromes, while somatic mutations of spliceosome components are linked to cell cycle dysregulation and cancer. Recently a group of craniofacial and skeletal disorders caused by dominant mutations in spliceosomal genes has emerged. The first of these to be identified is mandibulofacial dysostosis type Guion‐Almeida (MFDGA), caused by haploinsufficiency of the U5 snRNP component EFTUD2. We recently identified haploinsufficiency of SF3B4 as the cause of Nager syndrome, an acrofacial dysostosis (AFD), although only in 60% of cases suggesting genetic heterogeneity. Mutation of SF3B4 was subsequently reported in AFD Rodriquez type. SF3B4 is part of the U2 snRNP of the major spliceosome. We also identified heterozygous mutations in a highly conserved regulatory exon of SNRPBas the cause of cerebro‐costo‐mandibular syndrome (CCMS). Our experimental data show that these mutations disturb highly conserved exonic splicing silencer sequences crucial to the regulation of the gene's expression. SNRPB encodes a component of the Sm complex of the spliceosome. Additional craniofacial spliceosomopathies result from mutations in splicing factors TXNL4A, RBM8A and CWC27. The frequent involvement of craniofacial structures invite questions on the sensitivity of craniofacial and in particular pharyngeal arch development to spliceosomal defects, and on the role of the spliceosome in the regulation of development. The report of a young patient with Nager syndrome with bilateral synchronous breast cancer raises the possibility of a link between germline mutation of splicing factors and cancer predisposition. We also have a patient with a pathogenic SNRPB mutation who is non‐penetrant for CCMS syndrome but was diagnosed with early onset breast cancer, further linking heritable splicing mutations with cancer predisposition.Many of the craniofacial spliceosomopathies share overlapping features with Treacher‐Collins syndrome (TCS), a ribosomopathy. We are currently validating mutations in a ribosomal gene in two patients with typical Nager syndrome. This finding may provide unique insight into the overlapping roles of transcription and translation in craniofacial development. A combination of human genetics and model systems research will be required to further unravel the role of the spliceosome and the ribosome in craniofacial and skeletal development.Support or Funding InformationGenome Canada, Alberta Children's Hospital Research Institute, Genome AlbertaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Alterations in Sirt1 Attenuate Host Defense to Pneumococcal Infection in Sickle Cell Disease
Authors: Bedi Brahmchetna , Kang Bum‐Yong , Hart C Michael , Sadikot Ruxana T 
Published: June 2021

Sickle cell disease (SCD) is the most common inherited blood disorder in the United States. Bacterial pneumonia caused by Streptococcus pneumoniae, a gram‐positive pathogen, is a major contributor of morbidity and mortality in patients with SCD. Hence there is an urgent need to develop new strategies to enhance host defense for combating Pneumococcal infections in SCD. Hemolytic disorders such as SCD are characterized by the presence of large amounts of extracellular heme. Heme is a multifaceted contributor to cellular stress and a deregulator of cellular homeostasis, including host defense. We attempt to bridge the gap between dysregulation of cellular homeostasis and infection susceptibility caused by the presence of heme. Sirtuin1 (Sirt1), a protein deacetylase and an intracellular target of Resveratrol (RSV), has been shown to be attenuated in conditions of increased oxidative stress by heme. Heme induces the generation of reactive oxygen species (ROS) through the activation of NADPH oxidase. Human aortic endothelial cells (HAECs) treated with hem‐bound iron (hemin, 5 mM) showed a dose‐ and time‐dependent decrease in Sirt1 expression. This decrease in Sirt1 expression was concomitant with a significant increase in NAPDH oxidase (NOX4) expression. Increase in NOX4 expression was regulated by miR‐301b. Further, we found that depletion of Sirt1 in HAECs did not affect NOX4 expression, whereas knockdown in HAEC NOX4 significantly attenuated Sirt1 levels. These results indicate that NOX4 modulates Sirt1 expression. Total RNAs were isolated from lungs of sickle cell (SS) mice and littermate control (AA) mice at age 15–17 weeks. Levels of Sirt1 an NOX4 in lungs of SS mice were compared to AA mice using qRT‐PCR and Western blot analysis. Levels of Sirt1 were decreased in SS mouse lungs whereas NOX4 expression was increased, as compared with AA mouse lungs. The effect of hemin treatment on HAECs as well as silencing Sirt1 also significantly repressed the expression levels of anti‐microbial peptide (AMP), human beta defensin (hBD2), indicating alterations in host immunity. Treatment with RSV reversed these effects. RSV can be explored as a therapeutic modality to enhance host defenseSupport or Funding InformationDepartment of Veterans Affairs 2I01BX001786 (RTS)NIH HL133053 (BYK)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Transcriptional Response to Intermittent Hypoxia in the Heart of Germ‐Free Mice
Authors: Zhou Dan , Hartley Iain , Poulsen Orit , Xue Jin , Haddad Gabriel G 
Published: June 2021

Accumulating evidence has demonstrated that the gut microbiota plays a critical role in health and disease and regulates the organismal response to environmental stresses. For example, we have found that intermittent hypoxia/hypercapnia (IHH), a condition mimicking obstructive sleep apnea in humans, induced significant alterations in gut microbiome/metabolism and enhanced atherogenesis and progression in two atherosclerosis mouse models (i.e., the LDLR−/− and ApoE−/− mice). Indeed, with a joint microbiome and metabolome analysis, we have determined that IHH‐induced remarkable compositional changes in both microbial (>10%, most remarkably in Clostridia) and metabolites (>22%) in the gut of LDLR−/− mice, which are tightly correlated with a significantly enhanced atherosclerotic lesion formation in pulmonary arteries and aorta. In the current project, in order to further understand the role of the microbiome in the cardiovascular response to hypoxia and/or hypercapnia, we developed a set up that allows the treatment of experimental mice with different levels of O2 and/or CO2 in a germ‐free environment. Using this experimental set up, we studied the impact of the microbiome on transcriptional response to intermittent hypoxia (IH) in the left ventricle of mouse heart. We identified modest but significant changes in gene expression in both conventionally reared and germ‐free mice under IH condition. We found 52 significantly altered genes (19 up‐regulated and 33 down‐regulated) in the conventional mice and 76 significantly altered genes (24 upregulated and 52 down‐regulated) in the germ‐free mice. In addition, we found that these significantly altered genes play important roles in the development and function of cardiomyocytes and endothelial cells. Interestingly, there were only 15 genes (2 up‐regulated and 13 down‐regulated) that were commonly altered in both conventional and germ‐free mice, representing 28% changes in conventional mice and 20% changes in germ‐free mice, respectively. In summary, we discovered that IH induces distinct transcriptional alterations between conventional and germ‐free mice, which demonstrates that microbiome plays a critical role in the transcriptional response to IH in the left ventricle of mouse heart.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Stress Tolerance and Protein O‐GlcNAc Regulation in Neuroblastoma Cells under Hypoglycemic Condition
Authors: Nagy Zsófia , Kátai Emese , Miseta Attila , Nagy Tamas 
Published: June 2021

Alzheimer's disease is often referred to as type III diabetes since many studies demonstrated that glucose metabolism is significantly decreased in these patients. The exact mechanism how this metabolic change leads to Alzheimer's is still unclear. However Protein O‐linked N‐acetylglucosamine modification (O‐GlcNAc) may play a pivotal role in this process. O‐GlcNAc modification is a reversible post‐translational modification influenced by substrate availability (hexosamine pathway and UDP‐GlcNAc) which depends on glucose metabolism. Importantly, O‐GlcNAc and phosphorylation seems to be in balance on Tau‐protein, which may form neurofibrillary tangles if hyperphosphorylated. Despite of O‐GlcNAc's obvious connection to glucose metabolism, the level of O‐GlcNAc modification under hypoglycemic condition was not in the focus of research. Thus, the objective of this study was to investigate the relationship between O‐GlcNAc modification and Tau phosphorylation in a hypoglycemic cell culture model.We cultured the neuroblastoma cell line SH‐SY5Y in various amount of glucose‐containing media (5.5, 3, 1.5, 1, 0.5, 0.25 mM). In the first set of experiments, the glucose concentrations were kept constant for 96 hours. In a second set of experiments, we let the cells run out of glucose. Cell viability was analyzed by flow cytometry and direct microscopic observation. O‐GlcNAc, Tau‐Ps199, total Tau levels were detected by Western‐blot.We have found that SH‐SY5Y cells were resistant to very low level of glucose since the viability, cell morphology did not change significantly when compared to 5.5 mM glucose condition, as long as the media glucose was replenished to maintain the low, but steady level. However, when the cells were left to metabolize all of the glucose, the viability quickly deteriorated. O‐GlcNAc levels and P‐Tau levels were also steady, independent of the glucose concentration. In the second set of experiments, soon after glucose was completely depleted by the cells, O‐GlcNAc initially decreased then significantly elevated when detected with O‐GlcNAc specific antibody CTD110.6.In conclusion, our data suggest that hypoglycemic glucose concentrations could be still sufficient for neuronal cells, however glucose fasting quickly leads to cellular stress and eventually, cell death. In the future, we plan to study whether nutrient supplements, such as beta‐hydroxy‐butirate or galactose might alleviate or delay the effect of the unavailable glucose.Support or Funding InformationThis work was funded by the Research Fund of the University of Pécs, Faculty of Medicine (AOK‐KA 2018) and the EU founded Hungarian project GINOP 2.3.2.‐15 (grant No.: 2.3.2.‐15‐2016‐00050).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Human Resilience and the Gut Microbiome
Authors: Rusling Matthew , Johnson Joseph , Shoskes Aaron , Jie Chunfa , Yuan Lilian 
Published: June 2021

ObjectiveThis project evaluated the relationship of gut microbiome composition of first year medical students and stress resilience over a period of 4 months. Our objective was to identify gut microbiome characteristics of individuals that showed long term stress resilience.MethodsStudents were voluntarily recruited and screened for lifestyle and environmental factors. Their degree of psychologic stress at 3 timepoints during the first semester was measured with Cohen's perceived stress scale and PHQ‐9 depression scores. Fecal samples were collected at the same time using uBiome home kits at participant convenience. Samples were processed by uBiome and amplified for the 16s V4 gene. Stress and depression scores were normalized and summed to produce a psychologic index score. These scores were used to identify what microbiome characteristics may be correlated to stress resiliency of susceptibility. Metagenomic workup was performed using QIIME, MetaComet, and R Studio.Summary of resultsAcross phyla present in 100% of samples, none were independently correlated with psychologic scores using a linear model while Bacteroidete:Firmicute ratio showed a significant negative linear correlation with the psychologic index (Pearon's, p=0.05, R=−0.24). Phylogenetic assembly of participants by microbiome relatedness found that 100% of subjects who were resilient to stress across all timepoints (n=8) were phylogenetically clustered in adjacent positions, showing a high degree of temporal stability. Of participants who were not durably resilient to stress, only 62% of participants (n=8) showed microbiomes that were phylogenetically related across the same 4 month period. We identified 2,102 Operational Taxonomic Units (OTUs) which were unique to the durable resilience group and 94 OTUs which were unique to the susceptible group. Of the 4,794 observed OTUs, 6.1% (n=294) were significantly different between groups by Kruskal‐Wallis before post‐test adjustment.ConclusionFindings of a correlation between an index accounting for stress and depression and the abundance of Bacteroidetes: Firmicutes, and a relationship between durable resiliency and microbiome stability support that the gut microbiome may play an important role in stress resilience at a time scale of 4 months. More research is indicated in this field to identify microbiome characteristics which are responsible for stress resilience. These may include the presence or absence of specific taxa or ratios between taxa, such as the Bacteroidete:Firmicute ratio. Eventually, a better understanding of the role of the gut microbiome in stress resilience may someday create opportunities to help those with conditions which are characterized by low stress resilience when faced with new challenges. We hope someday that exploration of the microbiome will produce actionable, clinically relevant opportunities.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Sex‐specific differences in emergence patterns of solitary, cavity‐nesting bee, Megachile rotundata
Authors: DeBardlabon Korie Michelle , Bennett Meghan M , Yocum George D , Rinehart Joseph P , Greenlee Kendra 
Published: June 2021

Circadian rhythms play an important role in synchronizing biological processes. These rhythms are often influenced by semi‐predictable period cues, such as photoperiod or thermoperiod, often referred to as zeitgebers. The alfalfa leafcutting bee, Megachile rotundata, is a solitary, cavity‐nesting bee known to synchronize its emergence with thermoperiods as the dominant cue. Bees emerge as adults from brood cells. Brood cells are constructed by females with leaves and provisioned with pollen and nectar. One egg is laid in each brood cell, and a nest is composed of multiple brood cells in series in the cavity. Offspring go through all of juvenile development and metamorphosis in the cavity. It is unknown if certain variations in thermoperiod affects the timing of emergence. Because brood cells are built in series in the nest, adult offspring must emerge in a specific order to prevent bees placed at the back of the cavity from emerging before those in the front. If a bee in the back were to emerge first it would chew through its siblings' brood cells, potentially killing them, in order to exit the cavity. Thus, regulating emergence is important. On average, male M. rotundata are smaller than females, and often the brood cells at the front of cavities contain male offspring. Because of this, bee weight and sex are hypothesized to affect timing of emergence. To test this hypothesis, we disarticulated nests and placed individual brood cells in an apparatus that automatically records emergence time. We placed bees in various thermoperiods and recorded emergence time, sex, and dry weight of adult bees. It is well known that adult male offspring begin emerging days before females. In this study male offspring emerged earlier in the day than females which could be important for mating strategies. Understanding the roles sex and weight play in emergence and how these factors interact with different thermoperiods will help us to understand the maternal contribution to offspring development.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Orexin Receptor‐1 Inactivation Facilitates Lung Motor Activity during In Vitro Hypercapnic Stimulation of Pre‐metamorphic Bullfrogs
Authors: Janes Tara , Fonseca Elisa , Fournier Stéphanie , Gargaglioni Luciane , Kinkead Richard 
Published: June 2021

The mechanisms regulating amphibian respiration change dramatically during development as the animal transitions from aquatic to aerial breathing. Gill ventilation is the primary mechanism for oxygen acquisition in early stages, but infrequent lung breaths also occur. Interestingly, activating central chemoreceptive pathways (i.e. hypercapnia, hypoxia) can stimulate lung motor activity in tadpoles. Yet, the mechanisms which modulate chemosensitivity at various stages of development remain poorly understood in amphibians. Orexin is a critical hypothalamic neurotransmitter that is highly conserved across vertebrates and regulates important functions including sleep‐wake states, feeding, and breathing. In many vertebrates, orexinergic neurons are profoundly excited by increased CO2 (and decreased pH), suggesting that they are intrinsically chemosensitive. We hypothesized that antagonism of the orexin receptor‐1 (OX1R) would blunt the increased ventilatory response to hypercapnia in pre‐metamorphic tadpoles of the American bullfrog (Lithobates catesbeianus). Using tadpole brainstem preparations (Taylor‐Kollros stages: IV–XII), we determined the effects of hypercapnia alone (5% CO2, 20 mins), or in the presence of an OX1R antagonist (SB‐334867, 10μM) on respiratory motor activity recorded from cranial nerves V, VII and X. Isolated brainstems were transected rostral to the optic nerve to maintain an intact hypothalamus. Contrary to previous reports performed on preparations without the hypothalamus, our data showed no significant effect of hypercapnia on the frequency of lung bursting in this stage group. However, blocking OX1R's during hypercapnia revealed a significant ventilatory response observable as an increase in lung burst frequency (baseline respiratory motor activity was not affected by SB‐334867). Although these results were contrary to our hypothesis, they demonstrate that orexin inhibits the central CO2 chemoreflex of pre‐metamorphic bullfrog tadpoles.Support or Funding InformationThis work was supported by the Emerging Leaders in the Americas Program and Fonds de Recherche de Quebec ‐ Nature et Technologies awarded to E. Fonseca. Additional support was provided by the Fonds de Recherche du Québec ‐ Santé (FRQS) for T. Janes and an NSERC Discovery Grant awarded to R. Kinkead.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
African Spiny Mice as a Comparative Model of Spinal Cord Injury Repair and Recovery
Authors: Orr Michael , Bailey William , Richards Kirsten , Kopper Timothy , Seifert Ashley , Gensel John 
Published: June 2021

The adult mammalian central nervous system does not regeneration after injury. Spinal cord injury (SCI) results in a complex cascade of secondary damage responses that can exacerbate the initial injury or facilitate recovery. While inflammatory and fibrotic responses are known to be key regulators in promoting or repressing SCI repair, our understanding of their exact role in spinal regeneration is still evolving. While a mammalian model of enhanced regeneration would be invaluable for SCI studies, none currently exist. Translating therapies from non‐mammalian models that demonstrate spinal cord regeneration to mammals is complicated by a host of interspecific physiological differences. African spiny mice (genus Acomys) are a unique group of rodents that can regenerate full‐thickness skin, musculoskeletal tissue in the ear pinna, and recover from severe kidney injury. Multi‐organ tissue regeneration occurs coincident with inflammatory and scarring responses that are distinct from those of the non‐regenerating laboratory mouse (genus Mus). However, there are no published studies of Acomys regenerative capacity in the spinal cord. The objective of this study was to evaluate the potential of Acomys as a mammalian model of enhanced repair/recovery following spinal cord injury. Through histological analysis of uninjured tissue, we found that Acomys and Mus have similar gross neuroanatomical spinal structures. After SCI, motor and sensory functional tests revealed distinct functional recovery profiles between Acomys and Mus. Ongoing cellular studies of injured spinal tissue are investigating the macrophage and extracellular matrix profiles, which we predict to differ based on inflammatory and scarring responses to peripheral injuries. These preliminary data suggest that while Acomys and Mus have similar baseline spinal anatomy, the physiological response to injury is distinct and may provide insight to critical features leading mammalian SCI recovery and regeneration.Support or Funding Information5T32 NS077889This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.