Keratin 8 mutations in transgenic mice predispose to lung injury

Dual-color live imaging unveils stepwise organization of multiple basal body arrays by cytoskeletons

For mucociliary clearance of pathogens, tracheal multiciliated epithelial cells (MCCs) organize coordinated beating of cilia, which originate from basal bodies (BBs) with basal feet (BFs) on one side. To clarify the self-organizing mechanism of coordinated intracellular BB-arrays composed of a well-ordered BB-alignment and unidirectional BB-orientation, determined by the direction of BB to BF, we generated double transgenic mice with GFP-centrin2-labeled BBs and mRuby3-Cep128-labeled BFs for long-term, high-resolution, dual-color live-cell imaging in primary-cultured tracheal MCCs. At early timepoints of MCC differentiation, BB-orientation and BB-local alignment antecedently coordinated in an apical microtubule-dependent manner. Later during MCC differentiation, fluctuations in BB-orientation were restricted, and locally aligned BB-arrays were further coordinated to align across the entire cell (BB-global alignment), mainly in an apical intermediate-sized filament-lattice-dependent manner. Thus, the high coordination of the BB-array was established for efficient mucociliary clearance as the primary defense against pathogen infection, identifying apical cytoskeletons as potential therapeutic targets.

Intermediate filament proteins are reliable immunohistological biomarkers to help diagnose multiple tissue-specific diseases

Cytoskeletal networks are proteins that effectively maintain cell integrity and provide mechanical support to cells by actively transmitting mechanical signals. Intermediate filaments, which are from the cytoskeleton family and are 10 nanometres in diameter, are unlike actin and microtubules, which are highly dynamic cytoskeletal elements. Intermediate filaments are flexible at low strain, harden at high strain and resist breaking. For this reason, these filaments fulfil structural functions by providing mechanical support to the cells through their different strain-hardening properties. Intermediate filaments are suitable in that cells both cope with mechanical forces and modulate signal transmission. These filaments are composed of fibrous proteins that exhibit a central α-helical rod domain with a conserved substructure. Intermediate filament proteins are divided into six groups. Type I and type II include acidic and basic keratins, type III, vimentin, desmin, peripheralin and glial fibrillary acidic protein (GFAP), respectively. Type IV intermediate filament group includes neurofilament proteins and a fourth neurofilament subunit, α-internexin proteins. Type V consists of lamins located in the nucleus, and the type VI group consists of lens-specific intermediate filaments, CP49/phakinin and filen. Intermediate filament proteins show specific immunoreactivity in differentiating cells and mature cells of various types. Various carcinomas such as colorectal, urothelial and ovarian, diseases such as chronic pancreatitis, cirrhosis, hepatitis and cataract have been associated with intermediate filaments. Accordingly, this section reviews available immunohistochemical antibodies to intermediate filament proteins. Identification of intermediate filament proteins by methodological methods may contribute to the understanding of complex diseases.

[Viral hepatitis A to E: prevalence, pathogen characteristics, and pathogenesis]

Bei der viralen Hepatitis handelt es sich um eine akute oder chronische Entzündung der Leber, die durch verschiedene Viren verursacht wird. Weltweit leiden derzeit ca. 325 Mio. Menschen an der chronischen Form. Jährlich versterben insgesamt ca. 1,6 Mio. an den Folgen einer viralen Hepatitis. Die Hepatitisviren werden in 5 Erregergruppen unterteilt, die mit den Buchstaben A bis E bezeichnet werden (HAV–HEV). Diese unterscheiden sich in Phylogenie, Übertragung, Epidemiologie, Wirtsspezifität, Lebenszyklus, Struktur und in speziellen Aspekten der Pathogenese.

Das strikt humanpathogene HAV, Teil der Familie Picornaviridae, induziert meist nur akute Hepatitiden und ist primär in Entwicklungsländern verbreitet. Das den Hepeviridae zugeordnete HEV beschreibt eine ähnliche Epidemiologie, ist jedoch durch sein zoonotisches Potenzial auch in Industrienationen weitverbreitet und kann zusätzlich eine chronische Erkrankung induzieren. Eine Chronifizierung tritt ebenso bei dem weltweit verbreiteten HBV (Hepadnaviridae) auf, dessen Satellitenvirus HDV (Kolmioviridae) das vorhandene kanzerogene Potenzial noch einmal erhöht. Das ebenfalls weltweit verbreitete HCV (Flaviviridae) birgt ein äußerst hohes Risiko der Chronifizierung und somit ebenfalls ein stark erhöhtes, kanzerogenes Potenzial.

Die Erreger der viralen Hepatitis unterscheiden sich in ihren Eigenschaften und Lebenszyklen. Eine differenzierte Betrachtung im Hinblick auf Epidemiologie, Nachweismethoden und Prävention ist daher angezeigt. Obwohl robuste Therapien, und im Falle einzelner Erreger auch Vakzine, vorhanden sind, muss die Forschung insbesondere in Hinblick auf die armutsassoziierten Erreger erheblich vorangetrieben werden.