Nanotubes connecting B lymphocytes: High impact of differentiation-dependent lipid composition on their growth and mechanics

Nanotubes (NTs) are thin, long membranous structures forming novel, yet poorly known communication pathways between various cell types. Key mechanisms controlling their growth still remained poorly understood. Since NT-forming capacity of immature and mature B cells was found largely different, we investigated how lipid composition and molecular order of the membrane affect NT-formation. Screening B cell lines with various differentiation stages revealed that NT-growth linearly correlates with membrane ganglioside levels, while it shows maximum as a function of cholesterol level. NT-growth of B lymphocytes is promoted by raftophilic phosphatidylcholine and sphingomyelin species, various glycosphingolipids, and docosahexaenoic acid-containing inner leaflet lipids, through supporting membrane curvature, as demonstrated by comparative lipidomic analysis of mature versus immature B cell membranes. Targeted modification of membrane cholesterol and sphingolipid levels altered NT-forming capacity confirming these findings, and also highlighted that the actual lipid raft number may control NT-growth via defining the number of membrane-F-actin coupling sites. Atomic force microscopic mechano-manipulation experiments further proved that mechanical properties (elasticity or bending stiffness) of B cell NTs also depend on the actual membrane lipid composition. Data presented here highlight importance of the lipid side in controlling intercellular, nanotubular, regulatory communications in the immune system

Live cell superresolution-SIM imaging analysis of the intercellular transport of microvesicles and costimulatory proteins via nanotubes between immune cells

Halász, Henriett1,+, Ghadaksaz, Ali Reza1,2,+, Madarász, Tamás1, Huber, Krisztina2, Harami, Gábor3, Tóth, Eszter Angéla2, Osteikoetxea-Molnár, Anikó2, Kovács, Mihály3, Balogi, Zsolt5, Nyitrai, Miklós1,4, Matkó, János2,*, Szabó-Meleg, Edin

Effect of Inflammation on Female Gonadotropin-Releasing Hormone (GnRH) Neurons: Mechanisms and Consequences

Inflammation has a well-known suppressive effect on fertility. The function of gonadotropin-releasing hormone (GnRH) neurons, the central regulator of fertility is substantially altered during inflammation in females. In our review we discuss the latest results on how the function of GnRH neurons is modified by inflammation in females. We first address the various effects of inflammation on GnRH neurons and their functional consequences. Second, we survey the possible mechanisms underlying the inflammation-induced actions on GnRH neurons. The role of several factors will be discerned in transmitting inflammatory signals to the GnRH neurons: cytokines, kisspeptin, RFamide-related peptides, estradiol and the anti-inflammatory cholinergic pathway. Since aging and obesity are both characterized by reproductive decline our review also focuses on the mechanisms and pathophysiological consequences of the impact of inflammation on GnRH neurons in aging and obesity

Estradiol-Induced Epigenetically Mediated Mechanisms and Regulation of Gene Expression

Gonadal hormone 17β-estradiol (E2) and its receptors are key regulators of gene transcription by binding to estrogen responsive elements in the genome. Besides the classical genomic action, E2 regulates gene transcription via the modification of epigenetic marks on DNA and histone proteins. Depending on the reaction partner, liganded estrogen receptor (ER) promotes DNA methylation at the promoter or enhancer regions. In addition, ERs are important regulators of passive and active DNA demethylation. Furthermore, ERs cooperating with different histone modifying enzymes and chromatin remodeling complexes alter gene transcription. In this review, we survey the basic mechanisms and interactions between estrogen receptors and DNA methylation, demethylation and histone modification processes as well as chromatin remodeling complexes. The particular relevance of these mechanisms to physiological processes in memory formation, embryonic development, spermatogenesis and aging as well as in pathophysiological changes in carcinogenesis is also discussed

Adenovírus 8-as típusa okozta járványos keratoconjunctivitis molekuláris diagnosztikája = Molecular detection of adenovirus type 8 epidemic keratoconjunctivitis in Hungary

Bevezetés: A heveny kötőhártya-gyulladás (conjunctivitis) fertőzéses és nem fertőzéses eredetű lehet. A fertőzéses eredetű járványos conjunctivitisek (conjunctivitis epidemica) kórokozói vírusok, ezen belül elsősorban az adenovírusok különböző típusai. Célkitűzés: A szerzők célja egy keratoconjunctivitis járvány epidemiológiai leírása volt a virális kórokozó molekuláris kimutatásával. Módszer: A járvány – részben retrospektív – felderítésében klasszikus járványügyi módszereket alkalmaztak. A laboratóriumi etiológiai vizsgálat az adenovírus hexon régiójának kimutatásával polimeráz láncreakcióval (PCR), majd szekvenálással történt frissen gyűjtött conjunctiva-váladékból. Eredmények: A keratoconjunctivitis járványban összesen 60-an betegedtek meg 2006. október 9. és december 18-a között hét baranyai településen. A betegek átlagéletkora 51,2 év volt. A vezető tünetek a conjunctiva belövelltsége (100%), a könnyezés (94%), az idegentest-érzés (83%) és a homályos látás (76%) voltak. Az esetek felében mindkét szem érintett volt. A fertőzés közvetlen kontaktussal terjedt részben nosocomiálisan, a szemészeti szakellátás során. Nyolc conjunctivaváladékból 5-ben (62,5%) genetikailag azonos, 8-as típusú adenovírust lehetett kimutatni (HAdV8/Baranya/2006/HUN; EF210714), mely 100%-ban azonos volt egy Ausztriában 2004-ben kimutatott adenovírussal (DQ149614). Következtetések: A részben a szemészeti ellátáshoz kapcsolódó nosocomiális keratoconjunctivitis-járványt az adenovírus 8-as típusa okozta. A megbetegedés klinikai felismerése, laboratóriumi diagnosztikája és a járványügyi intézkedések együttesen szükségesek a keratoconjunctivitis-fertőzések és a következményes járvány megelőzéséhez. | Introduction: Both infectious and non-infectious forms of acute conjunctivitis are known. Viruses, especially different types of adenoviruses are the etiological agents of infectious epidemic conjunctivitis (conjunctivitis epidemica). Aims: The author’s aims were to describe an outbreak of keratoconjunctivitis and to detect the viral agent by molecular methods in Hungary. Materials and Methods: Classical epidemiological methods were used for investigation. Polymerase chain reaction (PCR) followed by sequencing were used for the detection of adenoviral hexon region from freshly collected conjunctival swabs. Results: Between 9 October and 18 December 2006, a total of 60 patients became ill with keratoconjunctivitis in 7 settlements in Southwest Hungary. Mean age was 51,2 years. Conjunctivitis (100%), lacrimation (94%), foreign body sensation (83%), and dim vision (76%) were the main clinical symptoms. Both eyes were affected in half of the cases. Direct contact was the main transmission route including nosocomial spread associated with ophtalmological practices. Five (62.5%) of 8 conjunctival swabs were PCR-positive for adenovirus type 8 (HAdV8/Baranya/2006/HUN; EF210714) which was genetically identical to adenovirus strain detected in Austria in 2004 (DQ149614). Conclusions: The outbreak of keratoconjunctivitis was partially associated with nosocomial infection caused by type 8 adenovirus. Both the recognition of the clinical illness, laboratory diagnosis and public health measures are necessary for the prevention of keratoconjunctivitis infection and epidemic

Detection and Quantification of Group C Rotaviruses in Communal Sewage▿

Group C rotaviruses have been recognized as a cause of acute gastroenteritis in humans, cattle, and swine, although the true epidemiologic and clinical importance of this virus in these hosts has not yet been fully established. A real-time PCR assay based on a broadly reactive primer pair was developed and used to quantitatively determine the viral load of group C rotaviruses in environmental samples. A total of 35 raw and 35 treated sewage samples collected at the same sampling time in four Hungarian sewage treatment plants during a survey in 2005 were tested for the presence of group C rotaviruses. The overall detection rates were 91% (32 of 35) for the influent and 57% (20 of 35) for the effluent samples. Molecular characterization of the amplified partial VP6 gene revealed the cocirculation of human and animal (i.e., bovine and porcine) strains that were easily distinguishable by melting curve analysis. Human strains yielded relatively high viral loads (mean, 1.2 × 107; median, 6.9 × 105 genome equivalents per liter influent sewage) and appeared to display seasonal activity over the study period, whereas animal strains appeared to circulate throughout the year at much lower average titers (bovine strains mean, 9.9 × 104; median, 3.0 × 104; porcine strains mean, 3.9 × 104; median, 3.1 × 104 genome equivalents per liter influent sewage). Our findings suggest that monitoring of communal sewage may provide a good surrogate for investigating the epidemiology and ecology of group C rotaviruses in humans and animals

The p53 and Calcium Regulated Actin Rearrangement in Model Cells

Long-term cellular stress maintains high intracellular Ca2+ concentrations which ultimately initiates apoptosis. Our interest is focused on how the gelsolin (GSN) and junctional mediating and regulating Y protein (JMY) play important roles in stress response. Both of these proteins can bind p53 and actin. We investigated using in vitro fluorescence spectroscopy and found that the p53 competes with actin in GSN to inhibit p53–JMY complex formation. A high Ca2+ level initializes p53 dimerization; the dimer competes with actin on JMY, which can lead to p53–JMY cotransport into the nucleus. Here we investigated how the motility and division rate of HeLa cells changes due to low-voltage electroporation of GSN or JMY in scratching assays. We revealed that JMY inhibits their motion, but that it can accelerate the cell division. GSN treatment slows down cell division but does not affect cell motility. HeLa cells fully recovered the gap 20 h after the electroporation with JMY and then started to release from the glass slides. Taken together, our in vitro results indicate that GSN and JMY may play an important role in the cellular stress response