Medical Microbiology Commons^™

Observations Of Shear Stress Effects On Staphylococcus Aureus Biofilm Formation, Erica Sherman, Kenneth W. Bayles, Derek E. Moormeier, Jennifer L. Endres, Timothy Wei

Journal Articles: Pathology and Microbiology

Staphylococcus aureus bacteria form biofilms and distinctive microcolony or "tower" structures that facilitate their ability to tolerate antibiotic treatment and to spread within the human body. The formation of microcolonies, which break off, get carried downstream, and serve to initiate biofilms in other parts of the body, is of particular interest here. It is known that flow conditions play a role in the development, dispersion, and propagation of biofilms in general. The influence of flow on microcolony formation and, ultimately, what factors lead to microcolony development are, however, not well understood. The hypothesis being examined is that microcolony structures form …

Urease Is An Essential Component Of The Acid Response Network Of Staphylococcus Aureus And Is Required For A Persistent Murine Kidney Infection, Chunyi Zhou, Fatema Bhinderwala, Mckenzie K. Lehman, Vinai Chittezham Thomas, Sujata S. Chaudhari, Kelsey J. Yamada, Kirk W. Foster, Robert Powers, Tammy Kielian, Paul D. Fey

Journal Articles: Pathology and Microbiology

Staphylococcus aureus causes acute and chronic infections resulting in significant morbidity. Urease, an enzyme that generates NH3 and CO2 from urea, is key to pH homeostasis in bacterial pathogens under acidic stress and nitrogen limitation. However, the function of urease in S. aureus niche colonization and nitrogen metabolism has not been extensively studied. We discovered that urease is essential for pH homeostasis and viability in urea-rich environments under weak acid stress. The regulation of urease transcription by CcpA, Agr, and CodY was identified in this study, implying a complex network that controls urease expression in response to changes in metabolic …

Oligomerization Of Bacterially Expressed H1n1 Recombinant Hemagglutinin Contributes To Protection Against Viral Challenge, Tess E. Kuenstling, Anthony R. Sambol, Steven H. Hinrichs, Marilynn A. Larson

Journal Articles: Pathology and Microbiology

Vaccination is the most effective intervention to prevent influenza and control the spread of the virus. Alternatives are needed to the traditional egg-based vaccine strategy for a more rapid response to new outbreaks. Two different hemagglutinin (HA) fragments (rHA1_1-326 and rHA1_53-269) derived from influenza A virus subtype H1N1 were expressed in Escherichia coli and characterized by immunoblot, gel filtration, hemagglutination, and competitive binding assays. rHA1_1-326 included neutralizing epitopes and the trimerization domain, whereas rHA1_53-269 included only the head of HA with the neutralizing epitopes. Mice were immunized with rHA1_1-326 or rHA1_53-269, and …

Searching For Novel Biomarkers Using A Mouse Model Of Cln3-Batten Disease, Derek Timm, Jacob T. Cain, Ryan D. Geraets, Katherine A. White, Seung Yon Koh, Tammy Kielian, David A. Pearce, Michelle L. Hastings, Jill M. Weimer

Journal Articles: Pathology and Microbiology

CLN3-Batten disease is a rare, autosomal recessive disorder involving seizures, visual, motor and cognitive decline, and premature death. The Cln3Δex7/8 mouse model recapitulates several phenotypic characteristics of the most common 1.02kb disease-associated deletion. Identification of reproducible biomarker(s) to facilitate longitudinal monitoring of disease progression and provide readouts for therapeutic response has remained elusive. One factor that has complicated the identification of suitable biomarkers in this mouse model has been that variations in animal husbandry appear to significantly influence readouts. In the current study, we cross-compared a number of biological parameters in blood from Cln3Δex7/8 mice and control, non-disease mice on …

Novel Long-Chain Compounds With Both Immunomodulatory And Mena Inhibitory Activities Against Staphylococcus Aureus And Its Biofilm., Seoung-Ryoung Choi, Joel Frandsen, Prabagaran Narayanasamy

Journal Articles: Pathology and Microbiology

Menaquinone (MK) biosynthesis pathway is a potential target for evaluating antimicrobials in gram-positive bacteria. Here, 1,4-dihydroxy-2-naphthoate prenyltransferase (MenA) was targeted to reduce methicillin-resistant Staphylococcus aureus (MRSA) growth. MenA inhibiting, long chain-based compounds were designed, synthesized and evaluated against MRSA and menaquinone utilizing bacteria in aerobic conditions. The results showed that these bacteria were susceptible to most of the compounds. Menaquinone (MK-4) supplementation rescued MRSA growth, suggesting these compounds inhibit MK biosynthesis. 3a and 7c exhibited promising inhibitory activities with MICs ranging 1-8 μg/mL against MRSA strains. The compounds did not facilitate small colony variant formation. These compounds also inhibited the …

Gallium Nanoparticles Facilitate Phagosome Maturation And Inhibit Growth Of Virulent Mycobacterium Tuberculosis In Macrophages., Seoung-Ryoung Choi, Bradley E. Britigan, David M. Moran, Prabagaran Narayanasamy

Journal Articles: Pathology and Microbiology

New treatments and novel drugs are required to counter the growing problem of drug-resistant strains of Mycobacterium tuberculosis (M.tb). Our approach against drug resistant M.tb, as well as other intracellular pathogens, is by targeted drug delivery using nanoformulations of drugs already in use, as well as drugs in development. Among the latter are gallium (III) (Ga)-based compounds. In the current work, six different types of Ga and rifampin nanoparticles were prepared in such a way as to enhance targeting of M.tb infected-macrophages. They were then tested for their ability to inhibit growth of a fully pathogenic strain (H37Rv) or a …

Neuroprotection Through Flavonoid: Enhancement Of The Glyoxalase Pathway., Joel Frandsen, Prabagaran Narayanasamy

Journal Articles: Pathology and Microbiology

The glyoxalase pathway functions to detoxify reactive dicarbonyl compounds, most importantly methylglyoxal. The glyoxalase pathway is an antioxidant defense mechanism that is essential for neuroprotection. Excessive concentrations of methylglyoxal have deleterious effects on cells, leading to increased levels of inflammation and oxidative stress. Neurodegenerative diseases - including Alzheimer's, Parkinson's, Aging and Autism Spectrum Disorder - are often induced or exacerbated by accumulation of methylglyoxal. Antioxidant compounds possess several distinct mechanisms that enhance the glyoxalase pathway and function as neuroprotectants. Flavonoids are well-researched secondary plant metabolites that appear to be effective in reducing levels of oxidative stress and inflammation in neural …

Membrane-Active Epithelial Keratin 6a Fragments (Kamps) Are Unique Human Antimicrobial Peptides With A Non-Αβ Structure., Judy T.Y. Lee, Guangshun Wang, Yu Tong Tam, Connie Tam

Journal Articles: Pathology and Microbiology

Antibiotic resistance is a pressing global health problem that threatens millions of lives each year. Natural antimicrobial peptides and their synthetic derivatives, including peptoids and peptidomimetics, are promising candidates as novel antibiotics. Recently, the C-terminal glycine-rich fragments of human epithelial keratin 6A were found to have bactericidal and cytoprotective activities. Here, we used an improved 2-dimensional NMR method coupled with a new protocol for structural refinement by low temperature simulated annealing to characterize the solution structure of these kerain-derived antimicrobial peptides (KAMPs). Two specific KAMPs in complex with membrane mimicking sodium dodecyl sulfate (SDS) micelles displayed amphipathic conformations with only …

Il-10 Plays An Important Role In The Control Of Inflammation But Not In The Bacterial Burden In S. Epidermidis Cns Catheter Infection., Yenis M. Gutierrez-Murgas, Gwenn Skar, Danielle Ramirez, Matthew Beaver, Jessica N. Snowden

Journal Articles: Pathology and Microbiology

BACKGROUND: Shunt infection is a frequent and serious complication in the surgical treatment in hydrocephalus. Previous studies have shown an attenuated immune response to these biofilm-mediated infections. We proposed that IL-10 reduces the inflammatory response to Staphylococcus epidermidis (S. epidermidis) CNS catheter infection.

METHODS: In this study, a murine model of catheter-associated S. epidermidis biofilm infection in the CNS was generated based on a well-established similar model for S. aureus. The catheters were pre-coated with a clinically derived biofilm-forming strain of S. epidermidis (strain 1457) which were then stereotactically implanted into the lateral left ventricle of 8-week-old C57BL/6 and IL-10 …

Nox2-Derived Oxidative Stress Results In Inefficacy Of Antibiotics Against Post-Influenza S. Aureus Pneumonia., Keer Sun, Vijaya Kumar Yajjala, Christopher Bauer, G. Talmon, Karl J. Fischer, Tammy Kielian, Dennis W. Metzger

Journal Articles: Pathology and Microbiology

Clinical post-influenza Staphylococcus aureus pneumonia is characterized by extensive lung inflammation associated with severe morbidity and mortality even after appropriate antibiotic treatment. In this study, we show that antibiotics rescue nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (Nox2)-deficient mice but fail to fully protect WT animals from influenza and S. aureus coinfection. Further experiments indicate that the inefficacy of antibiotics against coinfection is attributable to oxidative stress-associated inflammatory lung injury. However, Nox2-induced lung damage during coinfection was not associated with aggravated inflammatory cytokine response or cell infiltration but rather caused by reduced survival of myeloid cells. Specifically, oxidative stress increased …

Moving Towards Effective Therapeutic Strategies For Neuronal Ceroid Lipofuscinosis., Ryan D. Geraets, Seung Yon Koh, Michelle L. Hastings, Tammy Kielian, David A. Pearce, Jill M. Weimer

Journal Articles: Pathology and Microbiology

The Neuronal Ceroid Lipofuscinoses (NCLs) are a family of autosomal recessive neurodegenerative disorders that annually affect 1:100,000 live births worldwide. This family of diseases results from mutations in one of 14 different genes that share common clinical and pathological etiologies. Clinically, the diseases are subcategorized into infantile, late-infantile, juvenile and adult forms based on their age of onset. Though the disease phenotypes may vary in their age and order of presentation, all typically include progressive visual deterioration and blindness, cognitive impairment, motor deficits and seizures. Pathological hallmarks of NCLs include the accumulation of storage material or ceroid in the lysosome, …

Neuroinflammatory Paradigms In Lysosomal Storage Diseases., Megan Bosch, Tammy Kielian

Journal Articles: Pathology and Microbiology

Lysosomal storage diseases (LSDs) include approximately 70 distinct disorders that collectively account for 14% of all inherited metabolic diseases. LSDs are caused by mutations in various enzymes/proteins that disrupt lysosomal function, which impairs macromolecule degradation following endosome-lysosome and phagosome-lysosome fusion and autophagy, ultimately disrupting cellular homeostasis. LSDs are pathologically typified by lysosomal inclusions composed of a heterogeneous mixture of various proteins and lipids that can be found throughout the body. However, in many cases the CNS is dramatically affected, which may result from heightened neuronal vulnerability based on their post-mitotic state. Besides intrinsic neuronal defects, another emerging factor common to …

Primary Sclerosing Epithelioid Fibrosarcoma Of Kidney With Variant Histomorphologic Features: Report Of 2 Cases And Review Of The Literature., Dilek Ertoy Baydar, Kemal Kosemehmetoglu, Oguz Aydin, Julia A. Bridge, Berrin Buyukeren, Fazil Tuncay Aki

Journal Articles: Pathology and Microbiology

The authors present two cases of primary sclerosing epithelioid fibrosarcoma (SEF) of the kidney. Both patients had a mass in the upper part of the left kidney without any primary extrarenal neoplastic lesions. Grossly, the tumors were solid masses both measuring 7.5 cm in the greatest diameter. Histologically, one of the lesions exhibited a predominantly lobular growth of round or oval small uniform epithelioid cells in variable cellularity. Circular zones of crowded tumor cells alternating with hypocellular collagenous tissue in a concentric fashion around entrapped native renal tubules were distinctive. The second case was distinctive with significant cytological atypia in …

Identifying The Critical Domain Of Ll-37 Involved In Mediating Neutrophil Activation In The Presence Of Influenza Virus: Functional And Structural Analysis., Shweta Tripathi, Guangshun Wang, Mitchell White, Michael Rynkiewicz, Barbara Seaton, Kevan Hartshorn

Journal Articles: Pathology and Microbiology

The human cathelicidin LL-37 has been shown to play a role in host defense against influenza A viruses (IAV) through direct antiviral effects and through modulating inflammatory responses to infection. We recently showed that LL-37 increases neutrophil respiratory burst and neutrophil extracellular trap (NET) responses to IAV through engaging formyl peptide receptor 2 (FPR-2). In this paper we show that a fragment of LL-37, GI-20, which is composed of the central helical segment of the peptide, has similar effects as LL-37 on neutrophil activation. In addition to increasing respiratory burst and NET responses of the cells to IAV through an …

Staphylococcus Aureus Biofilms Induce Macrophage Dysfunction Through Leukocidin Ab And Alpha-Toxin., Tyler D. Scherr, Mark L. Hanke, Ouwen Huang, David B.A. James, Alexander R. Horswill, Kenneth W. Bayles, Paul D. Fey, Victor J. Torres, Tammy Kielian

Journal Articles: Pathology and Microbiology

UNLABELLED: The macrophage response to planktonic Staphylococcus aureus involves the induction of proinflammatory microbicidal activity. However, S. aureus biofilms can interfere with these responses in part by polarizing macrophages toward an anti-inflammatory profibrotic phenotype. Here we demonstrate that conditioned medium from mature S. aureus biofilms inhibited macrophage phagocytosis and induced cytotoxicity, suggesting the involvement of a secreted factor(s). Iterative testing found the active factor(s) to be proteinaceous and partially agr-dependent. Quantitative mass spectrometry identified alpha-toxin (Hla) and leukocidin AB (LukAB) as critical molecules secreted by S. aureus biofilms that inhibit murine macrophage phagocytosis and promote cytotoxicity. A role for Hla …

Irreversible Dual Inhibitory Mode: The Novel Btk Inhibitor Pls-123 Demonstrates Promising Anti-Tumor Activity In Human B-Cell Lymphoma., Ning Ding, Xitao Li, Yunfei Shi, Lingyan Ping, Lina Wu, Kai Fu, Lixia Feng, Xiaohui Zheng, Yuqin Song, Zhengying Pan, Jun Zhu

Journal Articles: Pathology and Microbiology

The B-cell receptor (BCR) signaling pathway has gained significant attention as a therapeutic target in B-cell malignancies. Recently, several drugs that target the BCR signaling pathway, especially the Btk inhibitor ibrutinib, have demonstrated notable therapeutic effects in relapsed/refractory patients, which indicates that pharmacological inhibition of BCR pathway holds promise in B-cell lymphoma treatment. Here we present a novel covalent irreversible Btk inhibitor PLS-123 with more potent anti-proliferative activity compared with ibrutinib in multiple cellular and in vivo models through effective apoptosis induction and dual-action inhibitory mode of Btk activation. The phosphorylation of BCR downstream activating AKT/mTOR and MAPK signal pathways …

Loss Of Cbl And Cbl-B Ubiquitin Ligases Abrogates Hematopoietic Stem Cell Quiescence And Sensitizes Leukemic Disease To Chemotherapy., Wei An, Scott A. Nadeau, Bhopal C. Mohapatra, Dan Feng, Neha Zutshi, Matthew D. Storck, Priyanka Arya, James E. Talmadge, Jane L. Meza, Vimla Band, Hamid Band

Journal Articles: Pathology and Microbiology

Cbl and Cbl-b are tyrosine kinase-directed RING finger type ubiquitin ligases (E3s) that negatively regulate cellular activation pathways. E3 activity-disrupting human Cbl mutations are associated with myeloproliferative disorders (MPD) that are reproduced in mice with Cbl RING finger mutant knock-in or hematopoietic Cbl and Cbl-b double knockout. However, the role of Cbl proteins in hematopoietic stem cell (HSC) homeostasis, especially in the context of MPD is unclear. Here we demonstrate that HSC expansion and MPD development upon combined Cbl and Cbl-b deletion are dependent on HSCs. Cell cycle analysis demonstrated that DKO HSCs exhibit reduced quiescence associated with compromised reconstitution …

Antiviral Activity Of The Human Cathelicidin, Ll-37, And Derived Peptides On Seasonal And Pandemic Influenza A Viruses., Shweta Tripathi, Guangshun Wang, Mitchell White, Li Qi, Jeffery Taubenberger, Kevan L. Hartshorn

Journal Articles: Pathology and Microbiology

Human LL-37, a cationic antimicrobial peptide, was recently shown to have antiviral activity against influenza A virus (IAV) strains in vitro and in vivo. In this study we compared the anti-influenza activity of LL-37 with that of several fragments derived from LL-37. We first tested the peptides against a seasonal H3N2 strain and the mouse adapted H1N1 strain, PR-8. The N-terminal fragment, LL-23, had slight neutralizing activity against these strains. In LL-23V9 serine 9 is substituted by valine creating a continuous hydrophobic surface. LL-23V9 has been shown to have increased anti-bacterial activity compared to LL-23 and we now show slightly …

Antimicrobial Peptides In 2014., Guangshun Wang, Biswajit Mishra, Kyle Lau, Tamara Lushnikova, Radha Golla, Xiuqing Wang

Journal Articles: Pathology and Microbiology

This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release …

Prolonged-Acting, Multi-Targeting Gallium Nanoparticles Potently Inhibit Growth Of Both Hiv And Mycobacteria In Co-Infected Human Macrophages., Prabagaran Narayanasamy, Barbara L. Switzer, Bradley E. Britigan

Journal Articles: Pathology and Microbiology

Human immunodeficiency virus (HIV) infection and Mycobacterium tuberculosis (TB) are responsible for two of the major global human infectious diseases that result in significant morbidity, mortality and socioeconomic impact. Furthermore, severity and disease prevention of both infections is enhanced by co-infection. Parallel limitations also exist in access to effective drug therapy and the emergence of resistance. Furthermore, drug-drug interactions have proven problematic during treatment of co-incident HIV and TB infections. Thus, improvements in drug access and simplified treatment regimens are needed immediately. One of the key host cells infected by both HIV and TB is the mononuclear phagocyte (MP; monocyte, …

Classification Of Current Anticancer Immunotherapies., Lorenzo Galluzzi, Erika Vacchelli, José-Manuel Bravo-San Pedro, Aitziber Buqué, Laura Senovilla, Elisa Elena Baracco, Norma Bloy, Francesca Castoldi, Jean-Pierre Abastado, Patrizia Agostinis, Ron N. Apte, Fernando Aranda, Maha Ayyoub, Philipp Beckhove, Jean-Yves Blay, Laura Bracci, Anne Caignard, Chiara Castelli, Federica Cavallo, Estaban Celis, Vincenzo Cerundolo, Aled Clayton, Mario P. Colombo, Lisa Coussens, Madhav V. Dhodapkar, Alexander M. Eggermont, Douglas T. Fearon, Wolf H. Fridman, Jitka Fučíková, Dmitry I. Gabrilovich, Jérôme Galon, Abhishek Garg, François Ghiringhelli, Giuseppe Giaccone, Eli Gilboa, Sacha Gnjatic, Axel Hoos, Anne Hosmalin, Dirk Jäger, Pawel Kalinski, Klas Kärre, Oliver Kepp, Rolf Kiessling, John M. Kirkwood, Eva Klein, Alexander Knuth, Claire E. Lewis, Roland Liblau, Michael T. Lotze, Enrico Lugli, Jean-Pierre Mach, Fabrizio Mattei, Domenico Mavilio, Ignacio Melero, Cornelis J. Melief, Elizabeth A. Mittendorf, Lorenzo Moretta, Adekunke Odunsi, Hideho Okada, Anna Karolina Palucka, Marcus E. Peter, Kenneth J. Pienta, Angel Porgador, George C. Prendergast, Gabriel A. Rabinovich, Nicholas P. Restifo, Naiyer Rizvi, Catherine Sautès-Fridman, Hans Schreiber, Barbara Seliger, Hiroshi Shiku, Bruno Silva-Santos, Mark J. Smyth, Daniel E. Speiser, Radek Spisek, Pramod K. Srivastava, James E. Talmadge, Eric Tartour, Sjoerd H. Van Der Burg, Benoît J. Van Den Eynde, Richard Vile, Hermann Wagner, Jeffrey S. Weber, Theresa L. Whiteside, Jedd D. Wolchok, Laurence Zitvogel, Weiping Zou, Guido Kroemer

Journal Articles: Pathology and Microbiology

During the past decades, anticancer immunotherapy has evolved from a promising therapeutic option to a robust clinical reality. Many immunotherapeutic regimens are now approved by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, and many others are being investigated as standalone therapeutic interventions or combined with conventional treatments in clinical studies. Immunotherapies may be subdivided into "passive" and "active" based on their ability to engage the host immune system against cancer. Since the anticancer activity of most passive immunotherapeutics (including tumor-targeting monoclonal antibodies) also relies on the host immune system, this classification …

Expression Of Suppressor Of Cytokine Signaling 1 (Socs1) Impairs Viral Clearance And Exacerbates Lung Injury During Influenza Infection., Keer Sun, Sharon Salmon, Vijaya Kumar Yajjala, Christopher Bauer, Dennis W. Metzger

Journal Articles: Pathology and Microbiology

Suppressor of cytokine signaling (SOCS) proteins are inducible feedback inhibitors of cytokine signaling. SOCS1-/- mice die within three weeks postnatally due to IFN-γ-induced hyperinflammation. Since it is well established that IFN-γ is dispensable for protection against influenza infection, we generated SOCS1-/-IFN-γ-/- mice to determine whether SOCS1 regulates antiviral immunity in vivo. Here we show that SOCS1-/-IFN-γ-/- mice exhibited significantly enhanced resistance to influenza infection, as evidenced by improved viral clearance, attenuated acute lung damage, and consequently increased survival rates compared to either IFN-γ-/- or WT animals. Enhanced viral clearance in SOCS1-/-IFN-γ-/- mice coincided with a rapid onset of adaptive immune …

Temporal And Stochastic Control Of Staphylococcus Aureus Biofilm Development., Derek E. Moormeier, Jeffrey L. Bose, Alexander R. Horswill, Kenneth W. Bayles

Journal Articles: Pathology and Microbiology

Biofilm communities contain distinct microniches that result in metabolic heterogeneity and variability in gene expression. Previously, these niches were visualized within Staphylococcus aureus biofilms by observing differential expression of the cid and lrg operons during tower formation. In the present study, we examined early biofilm development and identified two new stages (designated "multiplication" and "exodus") that were associated with changes in matrix composition and a distinct reorganization of the cells as the biofilm matured. The initial attachment and multiplication stages were shown to be protease sensitive but independent of most cell surface-associated proteins. Interestingly, after 6 h of growth, an …

Transformation Of Human Cathelicidin Ll-37 Into Selective, Stable, And Potent Antimicrobial Compounds., Guangshun Wang, Mark L. Hanke, Biswajit Mishra, Tamara Lushnikova, Cortney E. Heim, Vinai Chittezham Thomas, Kenneth W. Bayles, Tammy Kielian

Journal Articles: Pathology and Microbiology

This Letter reports a family of novel antimicrobial compounds obtained by combining peptide library screening with structure-based design. Library screening led to the identification of a human LL-37 peptide resistant to chymotrypsin. This d-amino-acid-containing peptide template was active against Escherichia coli but not methicillin-resistant Staphylococcus aureus (MRSA). It possesses a unique nonclassic amphipathic structure with hydrophobic defects. By repairing the hydrophobic defects, the peptide (17BIPHE2) gained activity against the ESKAPE pathogens, including Enterococcus faecium, S. aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter species. In vitro, 17BIPHE2 could disrupt bacterial membranes and bind to DNA. In vivo, the peptide …

Hemichannels In Neurodegenerative Diseases: Is There A Link To Pathology?, Megan Bosch, Tammy Kielian

Journal Articles: Pathology and Microbiology

Although originally considered a structural component of gap junctions, connexin hemichannels (HCs) are now recognized as functional entities capable of influencing metabolic gradients within the CNS, allowing direct communication between the intra- and extracellular milieus. Besides connexins, HCs can also be formed by pannexins, which are not capable of gap junction assembly. Both positive and negative effects have been attributed to HC activity in the context of neurodegenerative diseases. For example, HCs can exert neuroprotective effects by promoting the uptake of neurotoxic molecules, whereas chronic HC opening can disrupt molecular gradients leading to cellular dysfunction and death. The latter scenario …

Clinical And Biochemical Function Of Polymorphic Nr0b1 Ggaa-Microsatellites In Ewing Sarcoma: A Report From The Children's Oncology Group., Michael J. Monument, Kirsten M. Johnson, Elizabeth Mcilvaine, Lisa Abegglen, W. Scott Watkins, Lynn B. Jorde, Richard B. Womer, Natalie Beeler, Laura Monovich, Elizabeth R. Lawlor, Julia A. Bridge, Joshua D. Schiffman, Mark D Krailo, R. Lor Randall, Stephen L. Lessnick

Journal Articles: Pathology and Microbiology

BACKGROUND: The genetics involved in Ewing sarcoma susceptibility and prognosis are poorly understood. EWS/FLI and related EWS/ETS chimeras upregulate numerous gene targets via promoter-based GGAA-microsatellite response elements. These microsatellites are highly polymorphic in humans, and preliminary evidence suggests EWS/FLI-mediated gene expression is highly dependent on the number of GGAA motifs within the microsatellite.

OBJECTIVES: Here we sought to examine the polymorphic spectrum of a GGAA-microsatellite within the NR0B1 promoter (a critical EWS/FLI target) in primary Ewing sarcoma tumors, and characterize how this polymorphism influences gene expression and clinical outcomes.

RESULTS: A complex, bimodal pattern of EWS/FLI-mediated gene expression was observed …

A Central Role For Carbon-Overflow Pathways In The Modulation Of Bacterial Cell Death., Vinai Chittezham Thomas, Marat Sadykov, Sujata S. Chaudhari, Joselyn Jones, Jennifer L. Endres, Todd J. Widhelm, Jong-Sam Ahn, Randeep S. Jawa, Matthew C. Zimmerman, Kenneth W. Bayles

Journal Articles: Pathology and Microbiology

Similar to developmental programs in eukaryotes, the death of a subpopulation of cells is thought to benefit bacterial biofilm development. However mechanisms that mediate a tight control over cell death are not clearly understood at the population level. Here we reveal that CidR dependent pyruvate oxidase (CidC) and α-acetolactate synthase/decarboxylase (AlsSD) overflow metabolic pathways, which are active during staphylococcal biofilm development, modulate cell death to achieve optimal biofilm biomass. Whereas acetate derived from CidC activity potentiates cell death in cells by a mechanism dependent on intracellular acidification and respiratory inhibition, AlsSD activity effectively counters CidC action by diverting carbon flux …

Human Antimicrobial Peptides And Proteins, Guangshun Wang

Journal Articles: Pathology and Microbiology

As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids …

Evidence For Aberrant Astrocyte Hemichannel Activity In Juvenile Neuronal Ceroid Lipofuscinosis (Jncl)., Maria Burkovetskaya, Nikolay Karpuk, Juan Xiong, Megan Bosch, Michael D. Boska, Hideyuki Takeuchi, Akio Suzumura, Tammy Kielian

Journal Articles: Pathology and Microbiology

Juvenile Neuronal Ceroid Lipofuscinosis (JNCL) is a lysosomal storage disease caused by an autosomal recessive mutation in CLN3 that leads to vision loss, progressive cognitive and motor decline, and premature death. Morphological evidence of astrocyte activation occurs early in the disease process and coincides with regions where neuronal loss eventually ensues. However, the consequences of CLN3 mutation on astrocyte function remain relatively ill-defined. Astrocytes play a critical role in CNS homeostasis, in part, by their ability to regulate the extracellular milieu via the formation of extensive syncytial networks coupled by gap junction (GJ) channels. In contrast, unopposed hemichannels (HCs) have …

Functional Proteomic Analysis Reveals The Involvement Of Kiaa1199 In Breast Cancer Growth, Motility And Invasiveness., Mohammad-Saeid Jami, Jinxuan Hou, Miao Liu, M L. Varney, Hesham Hassan, Jixin Dong, Liying Geng, J. Wang, Fang Yu, Xin Huang, Hong Peng, Kai Fu, Yan Li, Rakesh Singh, Shi-Jian Ding

Journal Articles: Pathology and Microbiology

BACKGROUND: KIAA1199 is a recently identified novel gene that is up-regulated in human cancer with poor survival. Our proteomic study on signaling polarity in chemotactic cells revealed KIAA1199 as a novel protein target that may be involved in cellular chemotaxis and motility. In the present study, we examined the functional significance of KIAA1199 expression in breast cancer growth, motility and invasiveness.

METHODS: We validated the previous microarray observation by tissue microarray immunohistochemistry using a TMA slide containing 12 breast tumor tissue cores and 12 corresponding normal tissues. We performed the shRNA-mediated knockdown of KIAA1199 in MDA-MB-231 and HS578T cells to …