Angeborene Immunität: Bedeutung des Toll-Like Rezeptors 9 für die Entstehung der septischen Kardiomyopathie durch bakterielle DNA

Die Rolle des Angeborenen Immunsystems („innate immunity“) wurde lange Zeit nicht beachtet. Die Entdeckung der Toll-Like Rezeptoren (TLRs) hat dazu beigetragen, ihre Funktion besser zu verstehen, da sie sowohl in parenchymatischen Zellen der Gewebe als auch den zirkulierenden Immunzellen nachweisen lassen. Die Expression verschiedener TLRs wurde mehrfach im Myokard nachgewiesen. An Wildtyp- (WT) und TLR9-defizienten (TLR9-D) Mäusen wurde nach Stimulation mit synthetischen, immunstimulatorischen Oligonukleotiden (CpG-ODN) die Rolle von myokardialem TLR9 für die Entstehung einer septischen Kardiomyopathie untersucht. In der vorliegenden Arbeit wurde demonstriert, dass die Expression von TLR9 durch CpG-ODN reguliert wurde. In Kardiomyozyten erfolgte die Aufnahme von CpG-ODN ins Zytosol und den Nukleus unabhängig von der Präsenz von TLR9. Jedoch wurde die Aufnahme wurde durch TLR9 beschleunigt. Mit CpG-ODN wird in WT-Mäusen die Induktion von Mediatoren des Toll/IL-1-Signaltransduktionsweges eingeleitet. Die Aktivierung von NFkB und die Produktion pro-inflammatorischer Zytokine wurden im kardialen Gewebe nachgewiesen. In WT-Mäusen war die Zytokiproduktion im Vergleich zu TLR9-D Mäusen signifikant erhöht. Die Migration von Immunzellen in Herzen blieb aus. Dieses Ergebnis weist darauf hinweisen, dass der Ursprung der erhöhten Zytokinkonzentration von kardial-lokalisierten Zellen ausging. Knochenmarks(KM)-chimäre Mäusen, deren zirkulierende Immunzellen kein TLR9 exprimierten, zeigten eine Veränderung in ihrer Zytokinproduktion. Die Expression von IL-6 wurde verstärkt, wogegen die von TNF-α stark vermindert war. Der Vergleich zwischen Herz und Lunge hat zudem gezeigt, dass eine organspezifische Regulation vorliegt. Die Induktion der induzierbaren Stickstoffmonoxid-Synthetase (iNOS), die nur in WT-Mäusen nachgewiesen wurde, lieferte einen Hinweis auf das Vorliegen einer linksventrikulären Dysfunktion, die im Rahmen einer septischen Kardiomyopathie auftritt. Jedoch wurde innerhalb des Beobachtungszeitraumes keine Abnahme der Herzkontraktilität in vivo erfasst. Kontraktilitätsmessungen an einzelnen, linksventrikulären Kardiomyozyten belegten jedoch, dass CpG-ODN einen Einfluss in WT-Zellen hatte. In Zellen von TLR9-D Mäusen blieben diese Effekte aus. Zudem wurde in WT-Zellen die Kontraktilität durch den iNOS-Inhibitor S-Methylthioharnstoff (SMT) verbessert.Innate Immunity: Importance of Toll-Like receptor 9 in the development of septic cardiomyopathy by bacterial DNA The role of innate immunity was not paid attention for a long time. The identification of Toll-Like receptors (TLRs) was a major advance in understanding their function, as they are expressed in parenchymatic cells of tissues and circulating immune cells. Myocardial expression of TLRs was demonstrated several times. Wild-type (WT) and TLR9-deficient (TLR9-D) mice were stimulated with synthetic, immunostimulatory oligonucleotides (CpG-ODN) to investigate the role of myocardial TLR9 in the development of cardiomyopathy. These studies demonstrated the regulation of TLR9 by CpG-ODN. The uptake of CpG-ODN was demonstrated in the cytosol and the nucleus of cardiomyocytes, independently of the presence of TLR9. However, TLR9 accelerated the uptake. In WT mice, CpG-ODN initiated the induction of mediators in Toll/IL-1 signaling. Activation of NFkB and production of pro-inflammatory cytokines were detected in cardiac tissue. In contrast to TLR9-D mice, cytokine production was significantly elevated in WT mice. Migration of immune cells into the heart was absent. The results indicate that cardial localized cells were the source of elevated cytokine concentrations. Bone-marrow derived chimeric mice lacking TLR9 in circulating immune cells displayed an alteration in cytokine production. IL-6 expression was increased, whereas TNF-α was strongly diminished. Comparison of heart and lung in cytokine expression demonstrated organ-specific regulation. Induction of inducible nitric oxide synthase (iNOS) was detected in WT-mice which indicates the presence of left ventricular dysfunction contributing to septic cardiomyopathy. However, during observation a decrease in heart contractility was not recorded in vivo. Contractility measurements of isolated ventricular cardiomyocytes demonstrated the influence CpG-ODN in WT cells. These effects were absent in cells of TLR9-D mice. Application of the specific iNOS inhibitor S-methylisothiourea (SMT) improved contractility of WT cells

Toll-Like Receptor 9 Promotes Cardiac Inflammation and Heart Failure during Polymicrobial Sepsis

Background. Aim was to elucidate the role of toll-like receptor 9 (TLR9) in cardiac inflammation and septic heart failure in a murine model of polymicrobial sepsis. Methods. Sepsis was induced via colon ascendens stent peritonitis (CASP) in C57BL/6 wild-type (WT) and TLR9-deficient (TLR9-D) mice. Bacterial load in the peritoneal cavity and cardiac expression of inflammatory mediators were determined at 6, 12, 18, 24, and 36 h. Eighteen hours after CASP cardiac function was monitored in vivo. Sarcomere length of isolated cardiomyocytes was measured at 0.5 to 10 Hz after incubation with heat-inactivated bacteria. Results. CASP led to continuous release of bacteria into the peritoneal cavity, an increase of cytokines, and differential regulation of receptors of innate immunity in the heart. Eighteen hours after CASP WT mice developed septic heart failure characterised by reduction of end-systolic pressure, stroke volume, cardiac output, and parameters of contractility. This coincided with reduced cardiomyocyte sarcomere shortening. TLR9 deficiency resulted in significant reduction of cardiac inflammation and a sustained heart function. This was consistent with reduced mortality in TLR9-D compared to WT mice. Conclusions. In polymicrobial sepsis TLR9 signalling is pivotal to cardiac inflammation and septic heart failure

CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo-1

<p><b>Copyright information:</b></p><p>Taken from "CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo"</p><p>http://respiratory-research.com/content/8/1/72</p><p>Respiratory Research 2007;8(1):72-72.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2173891.</p><p></p> 2 hrs after stimulation with CpG-ODN, whereas there was only a reduced NFκB-DNA binding activity in TLR9-D mice detectable by EMSA

CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo-3

<p><b>Copyright information:</b></p><p>Taken from "CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo"</p><p>http://respiratory-research.com/content/8/1/72</p><p>Respiratory Research 2007;8(1):72-72.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2173891.</p><p></p>e at different time points following CpG-ODN stimulation. Results were normalized to total protein content of lung tissue. A maximum in cytokine production was observed 2 hrs after CpG-ODN challenge. TNF-α (A) and IL-1β (B) protein expression were significantly higher in WT compared to TLR9-D mice (mean ± SEM; * < 0.05)

Stabilization of a Cobalt Cobalt Bond by Two Cyclic Alkyl Amino Carbenes

10.1021/ja4123285JOURNAL OF THE AMERICAN CHEMICAL SOCIETY13651770-177

CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo-4

<p><b>Copyright information:</b></p><p>Taken from "CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo"</p><p>http://respiratory-research.com/content/8/1/72</p><p>Respiratory Research 2007;8(1):72-72.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2173891.</p><p></p>hnique. CpG-ODN led to a significant increase in plasma cytokine levels of TNF-α and IL-6 within 2 hrs (mean ± SEM; * < 0.05)

CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo-0

<p><b>Copyright information:</b></p><p>Taken from "CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo"</p><p>http://respiratory-research.com/content/8/1/72</p><p>Respiratory Research 2007;8(1):72-72.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2173891.</p><p></p>is (B, C). All data were normalized to control (0 h) (C). TLR9 was present even under base line conditions; however, no significant increase in TLR9 was observed after CpG-ODN stimulation (n = 3/group)

CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo-6

<p><b>Copyright information:</b></p><p>Taken from "CpG oligonucleotide activates Toll-like receptor 9 and causes lung inflammation in vivo"</p><p>http://respiratory-research.com/content/8/1/72</p><p>Respiratory Research 2007;8(1):72-72.</p><p>Published online 9 Oct 2007</p><p>PMCID:PMC2173891.</p><p></p>CpG-ODN challenge total cell counts were significantly higher in WT mice compared to TLR9-D animals (A). In WT animals a significant increase of neutrophils (PMNs) after CpG-ODN stimulation was observed (B), which was absent in TLR9-D mice (mean ± SEM; * < 0.05)