Publications by authors named "Ryan E Tyler"

15 Publications

  • Page 1 of 1

High frequency of anti-DSG 2 antibodies in post COVID-19 serum samples.

J Mol Cell Cardiol 2022 Jun 25;170:121-123. Epub 2022 Jun 25.

National Heart Centre, Singapore; Sengkang General Hospital, Singapore.

Background: There is growing recognition that COVID-19 does cause cardiac sequelae. The underlying mechanisms involved are still poorly understood to date. Viral infections, including COVID-19, have been hypothesized to contribute to autoimmunity, by exposing previously hidden cryptic epitopes on damaged cells to an activated immune system. Given the high incidence of cardiac involvement seen in COVID-19, our aim was to determine the frequency of anti-DSG2 antibodies in a population of post COVID-19 patients.

Methods And Results: 300 convalescent serum samples were obtained from a group of post COVID-19 infected patients from October 2020 to February 2021. 154 samples were drawn 6 months post-COVID-19 infection and 146 samples were drawn 9 months post COVID infection. 17 samples were obtained from the same patient at the 6- and 9- month mark. An electrochemiluminescent-based immunoassay utilizing the extracellular domain of DSG2 for antibody capture was used. The mean signal intensity of anti-DSG2 antibodies in the post COVID-19 samples was significantly higher than that of a healthy control population (19 ± 83.2 in the post-COVID-19 sample vs. 2.1 ± 7.2 (p < 0. 0001) in the negative control healthy population). Of note, 29.3% of the post COVID-19 infection samples demonstrated a signal higher than the 90th percentile of the control population and 8.7% were higher than the median found in ARVC patients. The signal intensity between the 6-month and 9-month samples did not differ significantly.

Conclusions: We report for the first time that recovered COVID-19 patients demonstrate significantly higher and sustained levels of anti-DSG2 autoantibodies as compared to a healthy control population, comparable to that of a diagnosed ARVC group.
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http://dx.doi.org/10.1016/j.yjmcc.2022.06.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9233549PMC
June 2022

The effects of predator odor (TMT) exposure and mGlu NAM pretreatment on behavioral and NMDA receptor adaptations in the brain.

Neuropharmacology 2022 04 7;207:108943. Epub 2022 Jan 7.

Neuroscience Curriculum, School of Medicine, University of North Carolina - Chapel Hill, Chapel Hill, NC, USA; Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, NC, USA; Department of Psychiatry, School of Medicine, University of North Carolina, Chapel Hill, NC, USA. Electronic address:

A stressor can trigger lasting adaptations that contribute to neuropsychiatric disorders. Predator odor (TMT) exposure is an innate stressor that may activate the metabotropic glutamate receptor 3 (mGlu) to produce stress adaptations. To evaluate functional involvement, the mGlu negative allosteric modulator (NAM, VU6010572; 3 mg/kg, i.p.) was administered before TMT exposure in male, Long Evans rats. Two weeks after, rats underwent context re-exposure, elevated zero maze (ZM), and acoustic startle (ASR) behavioral tests, followed by RT-PCR gene expression in the insular cortex and bed nucleus of the stria terminalis (BNST) to evaluate lasting behavioral and molecular adaptations from the stressor. Rats displayed stress-reactive behaviors in response to TMT exposure that were not affected by VU6010572. Freezing and hyperactivity were observed during the context re-exposure, and mGlu-NAM pretreatment during stressor prevented the context freezing response. TMT exposure did not affect ZM or ASR measures, but VU6010572 increased time spent in the open arms of the ZM and ASR habituation regardless of stressor treatment. In the insular cortex, TMT exposure increased expression of mGlu (Grm3, Grm5) and NMDA (GriN2A, GriN2B, GriN2C, GriN3A, GriN3B) receptor transcripts, and mGlu-NAM pretreatment blocked GriN3B upregulation. In the BNST, TMT exposure increased expression of GriN2B and GriN3B in vehicle-treated rats, but decreased expression in the mGlu-NAM group. Similar to the insular cortex, mGlu-NAM reversed the stressor-induced upregulation of GriN3B in the BNST. mGlu-NAM also upregulated GriN2A, GriN2B, GriN3B and Grm2 in the control group, but not the TMT group. Together, these data implicate mGlu receptor signaling in some lasting adaptations of predator odor stressor and anxiolytic-like effects.
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http://dx.doi.org/10.1016/j.neuropharm.2022.108943DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8844221PMC
April 2022

Interoception and alcohol: Mechanisms, networks, and implications.

Neuropharmacology 2021 12 23;200:108807. Epub 2021 Sep 23.

Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, USA; Neuroscience Curriculum, University of North Carolina at Chapel Hill, School of Medicine, USA; Department of Psychiatry, University of North Carolina at Chapel Hill, School of Medicine, USA. Electronic address:

Interoception refers to the perception of the internal state of the body and is increasingly being recognized as an important factor in mental health disorders. Drugs of abuse produce powerful interoceptive states that are upstream of behaviors that drive and influence drug intake, and addiction pathology is impacted by interoceptive processes. The goal of the present review is to discuss interoceptive processes related to alcohol. We will cover physiological responses to alcohol, how interoceptive states can impact drinking, and the recruitment of brain networks as informed by clinical research. We also review the molecular and brain circuitry mechanisms of alcohol interoceptive effects as informed by preclinical studies. Finally, we will discuss emerging treatments with consideration of interoception processes. As our understanding of the role of interoception in drug and alcohol use grows, we suggest that the convergence of information provided by clinical and preclinical studies will be increasingly important. Given the complexity of interoceptive processing and the multitude of brain regions involved, an overarching network-based framework can provide context for how focused manipulations modulate interoceptive processing as a whole. In turn, preclinical studies can systematically determine the roles of individual nodes and their molecular underpinnings in a given network, potentially suggesting new therapeutic targets and directions. As interoceptive processing drives and influences motivation, emotion, and subsequent behavior, consideration of interoception is important for our understanding of processes that drive ongoing drinking and relapse.
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http://dx.doi.org/10.1016/j.neuropharm.2021.108807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8541934PMC
December 2021

(3α,5α)3-hydroxypregnan-20-one (3α,5α-THP) regulation of hypothalamic and extrahypothalamic corticotropin releasing factor (CRF): Sexual dimorphism and brain region specificity in Sprague Dawley rats.

Neuropharmacology 2021 03 16;186:108463. Epub 2021 Jan 16.

Department of Psychiatry, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA; Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, 27599, USA. Electronic address:

CRF is the main activator of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress. CRF neurons are found mainly in the hypothalamus, but CRF positive cells and CRF1 receptors are also found in extrahypothalamic structures, including amygdala (CeA), hippocampus, NAc and VTA. CRF release in the hypothalamus is regulated by inhibitory GABAergic interneurons and extrahypothalamic glutamatergic inputs, and disruption of this balance is found in stress-related disorders and addiction. (3α,5α)3-hydroxypregnan-20-one (3α,5α-THP), the most potent positive modulator of GABA receptors, attenuates the stress response reducing hypothalamic CRF mRNA expression and ACTH and corticosterone serum levels. In this study, we explored 3α,5α-THP regulation of hypothalamic and extrahypothalamic CRF mRNA and peptide expression, in male and female Sprague Dawley rats, following vehicle or 3α,5α-THP administration (15 mg/kg). In the hypothalamus, we found sex differences in CRF mRNA expression (females +74%, p < 0.01) and CRF peptide levels (females -71%, p < 0.001). 3α,5α-THP administration reduced hypothalamic CRF mRNA expression only in males (-50%, p < 0.05) and did not alter CRF peptide expression in either sex. In hippocampus and CeA, 3α,5α-THP administration reduced CRF peptide concentrations only in the male (hippocampus -29%, p < 0.05; CeA -62%, p < 0.01). In contrast, 3α,5α-THP injection increased CRF peptide concentration in the VTA of both males (+32%, p < 0.01) and females (+26%, p < 0.01). The results show sex and region-specific regulation of CRF signals and the response to 3α,5α-THP administration. This data may be key to successful development of therapeutic approaches for stress-related disorders and addiction.
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http://dx.doi.org/10.1016/j.neuropharm.2021.108463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010646PMC
March 2021

Increased alcohol self-administration following exposure to the predator odor TMT in active coping female rats.

Behav Brain Res 2021 03 14;402:113068. Epub 2020 Dec 14.

Bowles Center for Alcohol Studies, United States; Neuroscience Curriculum, United States; Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States. Electronic address:

Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are highly comorbid. Additionally, individual differences in response to stress suggest resilient and susceptible populations. The current study exposed male and female Long Evans rats to the synthetically produced predator odor 2,5-dihydro-2,4,5-trimethylthiazoline (TMT) to examine individual differences in stress-reactive behaviors (digging and immobility) and whether these differences were related to subsequent alcohol drinking. Male and female Long Evans rats were trained on operant alcohol self-administration. After 9 sessions, rats underwent exposure to TMT or water (Control) in a distinct context. 6 days after TMT exposure, rats underwent re-exposure to the TMT-paired context (without TMT), and a series of behavioral assessments (acoustic startle, zero maze, light/dark box), after which rats resumed alcohol self-administration. TMT subgroups were created using a ratio of digging to immobility behavior during TMT exposure and rats with a ratio score < 1.0 or> 1.0 were grouped into TMT-1 (low digging/high immobility) or TMT-2 (high digging/low immobility), respectively. All male rats exposed to TMT met criteria for TMT-1, while female rats were divided into the two subgroups. In females, high digging/low immobility behavior during TMT exposure (TMT-2) was related to increased alcohol self-administration, but this was not observed in males or females that engaged in low digging/high immobility (TMT-1). These data show that individual differences in stress-reactivity can lead to lasting behavioral changes which may lead to a better understanding of increases in alcohol drinking following stress in females.
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http://dx.doi.org/10.1016/j.bbr.2020.113068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882035PMC
March 2021

Exposure to the predator odor TMT induces early and late differential gene expression related to stress and excitatory synaptic function throughout the brain in male rats.

Genes Brain Behav 2020 11 25;19(8):e12684. Epub 2020 Aug 25.

Neuroscience Curriculum, School of Medicine, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, USA.

Persistent changes in brain stress and glutamatergic function are associated with post-traumatic stress disorder (PTSD). Rodent exposure to the predator odor trimethylthiazoline (TMT) is an innate stressor that produces lasting behavioral consequences relevant to PTSD. As such, the goal of the present study was to assess early (6 hours and 2 days-Experiment 1) and late (4 weeks-Experiment 2) changes to gene expression (RT-PCR) related to stress and excitatory function following TMT exposure in male, Long-Evans rats. During TMT exposure, rats engaged in stress reactive behaviors, including digging and immobility. Further, the TMT group displayed enhanced exploration and mobility in the TMT-paired context 1 week after exposure, suggesting a lasting contextual reactivity. Gene expression analyses revealed upregulated FKBP5 6 hours post-TMT in the hypothalamus and dorsal hippocampus. Two days after TMT, GRM3 was downregulated in the prelimbic cortex and dorsal hippocampus, but upregulated in the nucleus accumbens. This may reflect an early stress response (FKBP5) that resulted in later glutamatergic adaptation (GRM3). Finally, another experiment 4 weeks after TMT exposure showed several differentially expressed genes known to mediate excitatory tripartite synaptic function in the prelimbic cortex (GRM5, DLG4 and SLC1A3 upregulated), infralimbic cortex (GRM2 downregulated, Homer1 upregulated), nucleus accumbens (GRM7 and SLC1A3 downregulated), dorsal hippocampus (FKBP5 and NR3C2 upregulated, SHANK3 downregulated) and ventral hippocampus (CNR1, GRM7, GRM5, SHANK3 and Homer1 downregulated). These data show that TMT exposure induces stress and excitatory molecular adaptations, which could help us understand the persistent glutamatergic dysfunction observed in PTSD.
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http://dx.doi.org/10.1111/gbb.12684DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655719PMC
November 2020

Detecting neuroinflammation in the brain following chronic alcohol exposure in rats: A comparison between in vivo and in vitro TSPO radioligand binding.

Eur J Neurosci 2019 07 25;50(1):1831-1842. Epub 2019 Mar 25.

National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland.

Excessive alcohol consumption is associated with neuroinflammation, which likely contributes to alcohol-related pathology. However, positron emission tomography (PET) studies using radioligands for the 18-kDa translocator protein (TSPO), which is considered a biomarker of neuroinflammation, reported decreased binding in alcohol use disorder (AUD) participants compared to controls. In contrast, autoradiographic findings in alcohol exposed rats reported increases in TSPO radioligand binding. To assess if these discrepancies reflected differences between in vitro and in vivo methodologies, we compared in vitro autoradiography (using [ H]PBR28 and [ H]PK11195) with in vivo PET (using [ C]PBR28) in male, Wistar rats exposed to chronic alcohol-vapor (dependent n = 10) and in rats exposed to air-vapor (nondependent n = 10). PET scans were obtained with [ C]PBR28, after which rats were euthanized and the brains were harvested for autoradiography with [ H]PBR28 and [ H]PK11195 (n = 7 dependent and n = 7 nondependent), and binding quantified in hippocampus, thalamus, and parietal cortex. Autoradiography revealed significantly higher binding in alcohol-dependent rats for both radioligands in thalamus and hippocampus (trend level for [ H]PBR28) compared to nondependent rats, and these group differences were stronger for [ H]PK11195 than [ H]PBR28. In contrast, PET measures obtained in the same rats showed no group difference in [ C]PBR28 binding. Our in vitro data are consistent with neuroinflammation associated with chronic alcohol exposure. Failure to observe similar increases in [ C]PBR28 binding in vivo suggests the possibility that a mechanism mediated by chronic alcohol exposure interferes with [ C]PBR28 binding to TSPO in vivo. These data question the sensitivity of PBR28 PET as a methodology to assess neuroinflammation in AUD.
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http://dx.doi.org/10.1111/ejn.14392DOI Listing
July 2019

Unassembled CD147 is an endogenous endoplasmic reticulum-associated degradation substrate.

Mol Biol Cell 2012 Dec 24;23(24):4668-78. Epub 2012 Oct 24.

Department of Biology, Stanford University, Stanford, CA 94305, USA.

Degradation of folding- or assembly-defective proteins by the endoplasmic reticulum-associated degradation (ERAD) ubiquitin ligase, Hrd1, is facilitated by a process that involves recognition of demannosylated N-glycans by the lectin OS-9/XTP3-B via the adaptor protein SEL1L. Most of our knowledge of the machinery that commits proteins to this fate in metazoans comes from studies of overexpressed mutant proteins in heterologous cells. In this study, we used mass spectrometry to identify core-glycoslyated CD147 (CD147(CG)) as an endogenous substrate of the ERAD system that accumulates in a complex with OS-9 following SEL1L depletion. CD147 is an obligatory assembly factor for monocarboxylate transporters. The majority of newly synthesized endogenous CD147(CG) was degraded by the proteasome in a Hrd1-dependent manner. CD147(CG) turnover was blocked by kifunensine, and interaction of OS-9 and XTP3-B with CD147(CG) was inhibited by mutations to conserved residues in their lectin domains. These data establish unassembled CD147(CG) as an endogenous, constitutive ERAD substrate of the OS-9/SEL1L/Hrd1 pathway.
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http://dx.doi.org/10.1091/mbc.E12-06-0428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521676PMC
December 2012

Defining human ERAD networks through an integrative mapping strategy.

Nat Cell Biol 2011 Nov 27;14(1):93-105. Epub 2011 Nov 27.

Department of Biology & Bio-X Program, Stanford University, Stanford, California 94305, USA.

Proteins that fail to correctly fold or assemble into oligomeric complexes in the endoplasmic reticulum (ER) are degraded by a ubiquitin- and proteasome-dependent process known as ER-associated degradation (ERAD). Although many individual components of the ERAD system have been identified, how these proteins are organized into a functional network that coordinates recognition, ubiquitylation and dislocation of substrates across the ER membrane is not well understood. We have investigated the functional organization of the mammalian ERAD system using a systems-level strategy that integrates proteomics, functional genomics and the transcriptional response to ER stress. This analysis supports an adaptive organization for the mammalian ERAD machinery and reveals a number of metazoan-specific genes not previously linked to ERAD.
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http://dx.doi.org/10.1038/ncb2383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3250479PMC
November 2011

OS-9 and GRP94 deliver mutant alpha1-antitrypsin to the Hrd1-SEL1L ubiquitin ligase complex for ERAD.

Nat Cell Biol 2008 Mar 10;10(3):272-82. Epub 2008 Feb 10.

Department of Biological Sciences & Bio-X Program, Stanford University, Lorry Lokey Bldg, 337 Campus Drive, Stanford, CA 94305, USA.

Terminally misfolded or unassembled proteins in the early secretory pathway are degraded by a ubiquitin- and proteasome-dependent process known as ER-associated degradation (ERAD). How substrates of this pathway are recognized within the ER and delivered to the cytoplasmic ubiquitin-conjugating machinery is unknown. We report here that OS-9 and XTP3-B/Erlectin are ER-resident glycoproteins that bind to ERAD substrates and, through the SEL1L adaptor, to the ER-membrane-embedded ubiquitin ligase Hrd1. Both proteins contain conserved mannose 6-phosphate receptor homology (MRH) domains, which are required for interaction with SEL1L, but not with substrate. OS-9 associates with the ER chaperone GRP94 which, together with Hrd1 and SEL1L, is required for the degradation of an ERAD substrate, mutant alpha(1)-antitrypsin. These data suggest that XTP3-B and OS-9 are components of distinct, partially redundant, quality control surveillance pathways that coordinate protein folding with membrane dislocation and ubiquitin conjugation in mammalian cells.
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http://dx.doi.org/10.1038/ncb1689DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2757077PMC
March 2008

Ternary complex formation on the adenovirus packaging sequence by the IVa2 and L4 22-kilodalton proteins.

J Virol 2007 Nov 5;81(22):12450-7. Epub 2007 Sep 5.

Department of Microbiology and Immunology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA.

Assembly of infectious adenovirus particles requires seven functionally redundant elements at the left end of the genome, termed A repeats, that direct packaging of the DNA. Previous studies revealed that the viral IVa2 protein alone interacts with specific sequences in the A repeats but that additional IVa2-containing complexes observed during infection require the viral L4 22-kDa protein. In this report, we purified a recombinant form of the 22-kDa protein to characterize its DNA binding properties. In electrophoretic mobility shift assay analyses, the 22-kDa protein alone did not interact with the A repeats but it did form complexes on them in the presence of the IVa2 protein. These complexes were identical to those seen in extracts from infected cells and had the same DNA sequence dependence. Furthermore, we provide data that the 22-kDa protein enhances binding of the IVa2 protein to the A repeats and that multiple binding sites in the packaging sequence augment this activity. These data support a cooperative role of the IVa2 and 22-kDa proteins in packaging and assembly.
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http://dx.doi.org/10.1128/JVI.01470-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2168966PMC
November 2007

Formation of a multiple protein complex on the adenovirus packaging sequence by the IVa2 protein.

J Virol 2007 Apr 17;81(7):3447-54. Epub 2007 Jan 17.

University of Michigan Medical School, 1500 East Medical Center Drive, 6304 Cancer Center, Ann Arbor, MI 48109-0942, USA.

During adenovirus virion assembly, the packaging sequence mediates the encapsidation of the viral genome. This sequence is composed of seven functional units, termed A repeats. Recent evidence suggests that the adenovirus IVa2 protein binds the packaging sequence and is involved in packaging of the genome. Study of the IVa2-packaging sequence interaction has been hindered by difficulty in purifying the protein produced in virus-infected cells or by recombinant techniques. We report the first purification of a recombinant untagged version of the adenovirus IVa2 protein and characterize its binding to the packaging sequence in vitro. Our data indicate that there is more than one IVa2 binding site within the packaging sequence and that IVa2 binding to DNA requires the A-repeat consensus, 5'-TTTG-(N(8))-CG-3'. Furthermore, we present evidence that IVa2 forms a multimeric complex on the packaging sequence. These data support a model in which adenovirus DNA packaging occurs via the formation of a IVa2 multiprotein complex on the packaging sequence.
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http://dx.doi.org/10.1128/JVI.02097-06DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1866038PMC
April 2007

Analysis of the interaction of the adenovirus L1 52/55-kilodalton and IVa2 proteins with the packaging sequence in vivo and in vitro.

J Virol 2005 Feb;79(4):2366-74

Department of Microbiology and Immunology and Comprehensive Cancer Center, University of Michigan Medical School, 1500 E. Medical Center Dr., Ann Arbor, MI 48109-0942, USA.

We previously showed that the adenovirus IVa2 and L1 52/55-kDa proteins interact in infected cells and the IVa2 protein is part of two virus-specific complexes (x and y) formed in vitro with repeated elements of the packaging sequence called the A1-A2 repeats. Here we demonstrate that both the IVa2 and L1 52/55-kDa proteins bind in vivo to the packaging sequence and that each protein-DNA interaction is independent of the other. There is a strong and direct interaction of the IVa2 protein with DNA in vitro. This interaction is observed when probes containing the A1-A2 or A4-A5 repeats are used, but it is not found by using an A5-A6 probe. Furthermore, we show that complex x is likely a heterodimer of IVa2 and an unknown viral protein, while complex y is a monomer or multimer of IVa2. No in vitro interaction of purified L1 52/55-kDa protein with the packaging sequence was found, suggesting that the L1 52/55-kDa protein-DNA interaction may be mediated by an intermediate protein. Results support roles for both the L1 52/55-kDa and IVa2 proteins in DNA encapsidation.
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http://dx.doi.org/10.1128/JVI.79.4.2366-2374.2005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC546600PMC
February 2005

In Silico Metabolic Model and Protein Expression of Haemophilus influenzae Strain Rd KW20 in Rich Medium.

OMICS 2004 ;8(1):25-41

Department of Bioengineering, University of California at San Diego, La Jolla, California, USA.

The intermediary metabolism of Haemophilus influenzae strain Rd KW20 was studied by a combination of protein expression analysis using a recently developed direct proteomics approach, mutational analysis, and mathematical modeling. Special emphasis was placed on carbon utilization, sugar fermentation, TCA cycle, and electron transport of H. influenzae cells grown microaerobically and anaerobically in a rich medium. The data indicate that several H. influenzae metabolic proteins similar to Escherichia coli proteins, known to be regulated by low concentrations of oxygen, were well expressed in both growth conditions in H. influenzae. An in silico model of the H. influenzae metabolic network was used to study the effects of selective deletion of certain enzymatic steps. This allowed us to define proteins predicted to be essential or non-essential for cell growth and to address numerous unresolved questions about intermediary metabolism of H. influenzae. Comparison of data from in vivo protein expression with the protein list associated with a genome-scale metabolic model showed significant coverage of the known metabolic proteome. This study demonstrates the significance of an integrated approach to the characterization of H. influenzae metabolism.
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http://dx.doi.org/10.1089/153623104773547471DOI Listing
November 2004

L12 enhances gonococcal transcytosis of polarized Hec1B cells via the lutropin receptor.

Microb Pathog 2002 Mar;32(3):117-25

Department of Microbiology and Immunology, School of Medicine and Dentistry, Rochester, NY 14642, U.S.A.

We previously reported that gonococci convert to a more invasive phenotype (Inv(+)GC) following contact with cells expressing the lutropin receptor (LHr) and that Inv(+)GC express a novel adhesin that interacts with LHr. We propose that this adhesion allows Inv(+)GC to activate LHr and induce gonococcal transcytosis, usurping normal LHr function in fallopian and endometrial epithelium, which is to transport fetal chorionic gonadotropin (hCG) into the mother. Infected polarized Hec1B monolayers, grown on collagen-coated transwells, showed that the passage of GC across the monolayer occurred rapidly, within 30 min, and proceeded at a constant rate with Inv(+)GC passage three-fold faster than GC grown in tissue culture media alone (Inv(-)GC). Electron microscopy found that Inv(+)GC triggered pseudopod formation around the bacterium, with GC found throughout the Hec1B targets within 30 min, while Inv(-)GC did neither. Pre-treatment of Inv(-)GC with recombinant ribosomal protein L12, a gonococcal "hCG-like" protein previously shown to increase invasion, also increased Inv(-)GC transcytosis to the rate of Inv(+)GC. This enhancement was completely abolished by addition of luteinizing hormone, a cognate ligand of LHr. This is convincing evidence that surface expressed L12 mediates gonococcal invasion and transcytosis via LHr, a mechanism that could be important in the development of invasive gonococcal disease in women.
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http://dx.doi.org/10.1006/mpat.2001.0484DOI Listing
March 2002
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