live-imaging-of-drosophila-melanogaster-embryonic-hemocyte-migrations

Live Imaging Of <em>Drosophila melanogaster </em>Embryonic Hemocyte Migrations

Many studies address cell migration using in vitro methods, whereas the physiologically relevant environment is that of the organism itself. Here we ...

Keratocytes can become fibroblasts and myofibroblasts during corneal injury and wound healing. We used the in vitro bovine keratocyte repair model system, which involves culturing collagenase-isolated keratocytes in serum-free media and then adding serum or serum plus TGF-beta to the culture media to induce the fibroblast and myofibroblast phenotypes, respectively, to evaluate the synthesis of secreted products by the cells. Serum and serum plus TGF-beta rapidly induced the fibroblast morphology and alpha smooth muscle actin, a marker of myofibroblasts. Keratocytes cultured in serum and serum plus TGF-beta also increased the synthesis of several high molecular weight products (approximately 100kD and larger) and the accumulation of a 43kD protein shown to be osteonectin/SPARC by both sequencing tryptic peptides from the protein and by reaction with antisera to osteonectin/SPARC. Immunohistochemical staining of mouse corneas with antisera to SPARC seven days post-wounding also demonstrated an increased accumulation of SPARC in the regions undergoing repair. These results indicate SPARC accumulation is a marker for stromal repair.

Increased SPARC accumulation during corneal repair.

Erh&#xF6;hte SPARC-Akkumulation w&#xE4;hrend der Hornhaut-Reparatur.

Incisional or ablation injury to the corneal stroma is repaired by deposition of a fibrotic tissue produced by activated keratocytes, whereas cells lost from the underlying stroma after epithelial abrasion are simply replaced by keratocyte replication without expression of fibrotic markers. The purpose of this study was to investigate mechanisms that determine this differential keratocyte response.

Molecular mechanisms controlling the fibrotic repair phenotype in cornea: implications for surgical outcomes.

Molekulare Mechanismen, die die Reparatur fibrotischen Ph&#xE4;notyp in Hornhaut: Implikationen f&#xFC;r die chirurgischen Ergebnisse.

To evaluate the anti-ganglioside monoclonal antibody 3G5 as a marker of corneal keratocytes.

Monoclonal antibody (3G5)-defined ganglioside: cell surface marker of corneal keratocytes.

Monoklonale Antik&#xF6;rper (3G5) Gangliosid-definiert: Zelloberfl&#xE4;chenmarker der Hornhaut Keratozyten.

Prolactin (PRL) has long been implicated in Xenopus metamorphosis as an anti-metamorphic and/or juvenilizing hormone. Numerous studies showed that PRL could prevent effects of either endogenous or exogenous thyroid hormone (TH; T(3)). It has been shown that expression of matrix metalloproteinases (MMPs) is induced by TH during Xenopus metamorphosis. Direct in vivo evidence, however, for such anti-TH effects by PRL with respect to MMPs has not been available for the early phase of Xenopus development or metamorphosis. To understand the functional role of PRL, we investigated effects of PRL on Xenopus collagenase-3 (XCL3) and collagenase-4 (XCL4) expression in a cultured Xenopus laevis cell line, XL-177. Northern blot analysis demonstrated that XCL3 and XCL4 expression were not detected in control or T(3)-treated cells, but were differentially induced by PRL in a dose- and time-dependent fashion. Moreover, treatment with IL-1alpha as well as phorbol myristate acetate (PMA), a protein kinase C (PKC) activator, or H8, a protein kinase A (PKA) inhibitor, augmented PRL-induced collagenase expression, suggesting that multiple protein kinase pathways and cytokines may participate in PRL-induced collagenase expression. Interestingly, XCL3 expression could be induced in XL-177 cells by T(3), but only when co-cultured with prometamorphic Xenopus tadpole tails (stage 54/55), suggesting that the tails secrete a required intermediate signaling molecule(s) for T(3)-induced XCL3 expression. Taken together, these data demonstrate that XCL3 and XCL4 can be differentially induced by PRL and T(3) and further suggest that PRL is a candidate regulator of TH-independent collagenase expression during the organ/tissue remodeling which occurs in Xenopus development.

Activity and expression of Xenopus laevis matrix metalloproteinases: identification of a novel role for the hormone prolactin in regulating collagenolysis in both amphibians and mammals.

Aktivit&#xE4;t und Expression von Xenopus laevis Matrixmetalloproteinasen: Identifikation einer neuen Rolle f&#xFC;r das Hormon Prolaktin bei der Regulierung Kollagenolyse sowohl Amphibien und S&#xE4;ugetiere.

Corneal crystallins are lost from resident cells of the corneal stroma during wound repair, and this is associated with a loss of cell transparency. The goal of this study was to identify factors inducing loss of the corneal crystallin transketolase (TKT).

Uncoupling keratocyte loss of corneal crystallin from markers of fibrotic repair.

Entkopplung Keratozyten Ausfall der Corneal-Kristallin aus Marker der fibrotischen Reparatur.

The cytokine transforming growth factor-beta (TGF-beta) is a key mediator of fibrosis in all organs. Expression of fibrotic markers in repairing cutaneous wounds is reduced in mice lacking Smad3, a downstream cytoplasmic mediator of TGF-beta signaling (Ashcroft et al., 1999, Nat Cell Biol 1(5):260-266). This is correlated with a reduction in inflammation, and thus in the blood elements thought to be a significant source of TGF-beta at the wound site, the principle form being TGF-beta1. Since the major cellular source of TGF-beta in corneal wounds is the epithelium, and the principal isoform is TGF-beta2, we investigated whether Smad3 deficiency has similar anti-fibrotic effects on corneal repair. In contrast to the situation of cutaneous repair, expression of the fibrotic marker, fibronectin, was equivalent in corneal repair tissue of Smad3-/- mice as compared to their +/- littermates, even though expression of a second fibrotic marker not previously examined in cutaneous wounds, alpha-smooth muscle (sm) actin, was reduced. Also unlike in cutaneous wounds, the inflammatory response was unaffected. These differences between corneal and cutaneous repair correlated with the lack of apparent change in the levels of corneal TGF-beta2. There was a significant reduction of alpha-sm actin expression in stromal cell cultures established from Smad3-/- mice as compared to their +/- littermates, but the rate of cell proliferation stimulated by TGF-beta, as well as expression of fibronectin, was unaffected. Therefore, a deficiency in Smad3 has different effects on corneal and cutaneous repair, probably due to the difference in cellular source and principal isoform of the TGF-beta involved.

Selective reduction of fibrotic markers in repairing corneas of mice deficient in Smad3.

Die selektive Reduktion von fibrotischen Markern bei der Reparatur von Hornhaut-defizienten M&#xE4;usen Smad3.

In mammals, penetrating injuries typically heal by deposition of fibrotic "repair tissue" that fills and seals wounds but does not restore normal function. Excessive deposition of fibrotic repair tissue can lead to pathologies involving excessive scarring and contracture. In the cornea, fibrotic repair presents special challenges affecting both clarity and shape of the cornea. With the increasing popularity of surgical techniques that alter corneal refractive errors, understanding of cornea repair mechanisms has acquired new significance. The cornea has unique anatomic, cellular, molecular, and functional features that lead to important mechanistic differences in the process of repair in comparison with what occurs in skin and other organs. Moreover, corneal function calls for special outcomes. This review addresses these features from the viewpoint of the authors' research on factors of importance to understanding and improving surgical outcomes.

How the cornea heals: cornea-specific repair mechanisms affecting surgical outcomes.

Bei S&auml;ugetieren durchdringende Verletzungen heilen in der Regel durch Ablagerung von fibrotische &quot;Reparatur Gewebe&quot;, das f&uuml;llt und verschlie&szlig;t Wunden aber nicht wieder normal funktioniert. &Uuml;berm&auml;&szlig;ige Ablagerung von fibrotische Reparatur Gewebe kann zu Pathologien, die mit &uuml;berm&auml;&szlig;iger Narbenbildung und Kontraktur f&uuml;hren. In der Hornhaut pr&auml;sentiert fibrotische Reparatur besondere Anforderungen an die Klarheit und die Form der Hornhaut. Mit der zunehmenden Beliebtheit von Operationstechniken, die Hornhaut Brechungsfehler zu &auml;ndern, hat Verst&auml;ndnis f&uuml;r Hornhaut Reparaturmechanismen neue Bedeutung erworben. Die Hornhaut hat einzigartige anatomische, Zellbiologie, Molekulare und funktionelle Eigenschaften, die dazu, dass wichtige mechanistische Unterschiede in den Prozess der Reparatur im Vergleich zu dem f&uuml;hren, was geschieht in der Haut und andere Organe. Dar&uuml;ber hinaus ruft die Hornhaut Funktion f&uuml;r besondere Ergebnisse. Diese Bewertung wird diese Features aus der Sicht der Autoren Forschung auf Faktoren von Bedeutung zum Verst&auml;ndnis und zur Verbesserung der chirurgischen Ergebnisse.

Wie die Hornhaut heilt: Hornhaut-spezifische Repair-Mechanismen, die chirurgischen Ergebnisse beeinflussen.

The healing of a skin wound is a complex process involving many cell lineages. In adult tissues, repair is always accompanied by a robust inflammatory response, which is necessary to counter the potential for infection at any site where the skin barrier is breached. Unlike embryonic tissues that can repair perfectly without a remnant scar at the wound site, adult tissue repair always leads to formation of a fibrotic scar where the wound has healed. In recent years, it has become clear that the wound inflammatory response may be, at least in part, responsible for fibrosis at sites of tissue repair. In this review, we consider the beneficial vs the detrimental functions of inflammatory cells during the repair response and compare data from other tissues, the lung, and liver, where fibrosis and its resolution may be related to a damage-triggered inflammatory response. We also consider how it may be possible to molecularly disentangle the potentially good from the bad influences of inflammatory cells during tissue repair and how fundamental studies in inflammatory cell biology may prove the way forward for development of drug targets in this respect.

The inflammation-fibrosis link? A Jekyll and Hyde role for blood cells during wound repair.

Die Heilung der Wunde Haut ist ein komplexer Prozess, der mit vielen Zelle-&Uuml;bertragungslinien. Im Gewebe Erwachsener ist Reparatur immer begleitet von einer robusten Entz&uuml;ndungsreaktion, die ist notwendig, um das Potenzial f&uuml;r eine Infektion an jedem Ort zu begegnen, wo die Hautbarriere verletzt wird. Im Gegensatz zu embryonalen Gewebe, die vollkommen ohne &Uuml;berrest Narbe am Standort Wunde reparieren k&ouml;nnen, f&uuml;hrt Reparatur von Erwachsenen Gewebe immer zu Bildung von eine fibrotische Narbe wo hat die Wunde geheilt. In den letzten Jahren deutlich geworden, dass die Wunde entz&uuml;ndliche Reaktion, zumindest teilweise verantwortlich f&uuml;r Fibrose an Standorten der Reparatur von Gewebe sein kann. In diesem Bericht wir betrachten die Vorteil gegen die sch&auml;dlichen Funktionen der Entz&uuml;ndungszellen w&auml;hrend der Reparatur-Antwort und Vergleichen von Daten aus anderen Geweben, die Lunge und Leber, wo Fibrose und ihre L&ouml;sung mit einer Schaden-ausgel&ouml;ste Entz&uuml;ndungsreaktion verbunden sein k&ouml;nnen. Wir auch &uuml;berlegen, wie es w&auml;hrend der Reparatur von Gewebe molekular der potentiell guten von den schlechten Einfl&uuml;ssen von Entz&uuml;ndungszellen entwirren werden kann und wie Fundamental studies in entz&uuml;ndliche Zelle Biologie den Weg f&uuml;r die Entwicklung von Medikamenten Zielen in dieser Hinsicht erweisen k&ouml;nnte.

Article	Year
Increased SPARC accumulation during corneal repair. Experimental eye research\| PubMed ID: 12823991	2003
Molecular mechanisms controlling the fibrotic repair phenotype in cornea: implications for surgical outcomes. Investigative ophthalmology & visual science\| PubMed ID: 14507867	2003
Monoclonal antibody (3G5)-defined ganglioside: cell surface marker of corneal keratocytes. Investigative ophthalmology & visual science\| PubMed ID: 14985294	2004
Activity and expression of Xenopus laevis matrix metalloproteinases: identification of a novel role for the hormone prolactin in regulating collagenolysis in both amphibians and mammals. Journal of cellular physiology\| PubMed ID: 15281098	2004
Uncoupling keratocyte loss of corneal crystallin from markers of fibrotic repair. Investigative ophthalmology & visual science\| PubMed ID: 15505050	2004
Selective reduction of fibrotic markers in repairing corneas of mice deficient in Smad3. Journal of cellular physiology\| PubMed ID: 15521071	2005
How the cornea heals: cornea-specific repair mechanisms affecting surgical outcomes. Cornea\| PubMed ID: 16227819	2005
The inflammation-fibrosis link? A Jekyll and Hyde role for blood cells during wound repair. The Journal of investigative dermatology\| PubMed ID: 17435786	2007

Brian M. Stramer

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