Inferring Tissue-Specific, TLR4-Dependent Type 17 Immune Interactions in Experimental Trauma/Hemorrhagic Shock and Resuscitation Using Computational Modeling.

Trauma/hemorrhagic shock followed by resuscitation (T/HS-R) results in multi-system inflammation and organ dysfunction, in part driven by binding of damage-associated molecular pattern molecules to Toll-like Receptor 4 (TLR4). We carried out experimental T/HS-R (pseudo-fracture plus 2 h of shock followed by 0-22 h of resuscitation) in C57BL/6 (wild type [WT]) and TLR4-null (TLR4-/-) mice, and then defined the dynamics of 20 protein-level inflammatory mediators in the heart, gut, lung, liver, spleen, kidney, and systemic circulation. Cross-correlation and Principal Component Analysis (PCA) on data from the 7 tissues sampled suggested that TLR4-/- samples express multiple inflammatory mediators in a small subset of tissue compartments as compared to the WT samples, in which many inflammatory mediators were localized non-specifically to nearly all compartments. We and others have previously defined a central role for type 17 immune cells in human trauma. Accordingly, correlations between IL-17A and GM-CSF (indicative of pathogenic Th17 cells); between IL-17A and IL-10 (indicative of non-pathogenic Th17 cells); and IL-17A and TNF (indicative of memory/effector T cells) were assessed across all tissues studied. In both WT and TLR4-/- mice, positive correlations were observed between IL-17A and GM-CSF, IL-10, and TNF in the kidney and gut. In contrast, the variable and dynamic presence of both pathogenic and non-pathogenic Th17 cells was inferred in the systemic circulation of TLR4-/- mice over time, suggesting a role for TLR4 in efflux of these cells into peripheral tissues. Hypergraph analysis - used to define dynamic, cross compartment networks - in concert with PCA-suggested that IL-17A was present persistently in all tissues at all sampled time points except for its absence in the plasma at 0.5h in the WT group, supporting the hypothesis that T/HS-R induces efflux of Th17 cells from the circulation and into specific tissues. These analyses suggest a complex, context-specific role for TLR4 and type 17 immunity following T/HS-R.

ER stress preconditioning ameliorates liver damage after hemorrhagic shock and reperfusion.

The mismatch of oxygen supply and demand during hemorrhagic shock disturbs endoplasmic reticulum (ER) homeostasis. The resulting accumulation of unfolded proteins in the ER lumen, which is a condition that is defined as ER stress, triggers the unfolded protein response (UPR). Since the UPR influences the extent of organ damage following hemorrhagic shock/reperfusion (HS/R) and mediates the protective effects of stress preconditioning before ischemia-reperfusion injury, the current study investigated the mechanisms of ER stress preconditioning and its impact on post-hemorrhagic liver damage. Male C56BL/6-mice were injected intraperitoneally with the ER stress inductor tunicamycin (TM) or its drug vehicle 48 h prior to being subjected to a 90 min pressure-controlled hemorrhagic shock (30±5 mmHg). A period of 14 h after hemorrhagic shock induction, mice were sacrificed. Hepatocellular damage was quantified by analyzing hepatic transaminases and hematoxylin-eosin stained liver tissue sections. Additionally, the topographic expression patterns of the ER stress marker binding immunoglobulin protein (BiP), UPR signaling pathways, and the autophagy marker Beclin1 were evaluated. TM injection significantly increased BiP expression and modified the topographic expression patterns of the UPR signaling proteins. In addition, immunohistochemical analysis of Beclin1 revealed an increased pericentral staining intensity following TM pretreatment. The histologic analysis of hepatocellular damage demonstrated a significant reduction in cell death areas in HS/R+TM (P=0.024). ER stress preconditioning influences the UPR and alleviates post-hemorrhagic liver damage. The beneficial effects were, at least partially, mediated by the upregulation of BiP and autophagy induction. These results underscore the importance of the UPR in the context of HS/R and may help identify novel therapeutic targets.

Modulation of Endoplasmic Reticulum Stress Influences Ischemia-Reperfusion Injury After Hemorrhagic Shock.

BACKGROUND: Impaired function of the endoplasmic reticulum (ER) results in ER stress, an accumulation of proteins in the ER lumen. ER stress is a major contributor to inflammatory diseases and is part of the pathomechanism of ischemia-reperfusion injury (IRI). Since severe traumatic injury is often accompanied by remote organ damage and immune cell dysfunction, we investigated the influence of ER stress modulation on the systemic inflammatory response and liver damage after hemorrhagic shock and reperfusion (HS/R). MATERIAL AND METHODS: Male C56BL/6-mice were subjected to hemorrhagic shock with a mean arterial pressure of 30 ±â€Š5 mm Hg. After 90 min mice were resuscitated with Ringer solution. Either the ER stress inductor tunicamycin (TM), its drug vehicle (DV), or the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) were added to reperfusion solution. Animals were sacrificed 14 h after shock induction and plasma concentrations of liver transaminases as well as inflammatory cytokines were measured. In addition, liver tissue sections were embedded in paraffin. For the quantification of hepatocellular damage hematoxylin and eosin stained tissue sections were analyzed. Furthermore, the topographic patterns of ER stress marker proteins were evaluated using immunohistochemistry. RESULTS: ER stress modulation influenced the topographic pattern of ER stress marker proteins. The alterations were particularly seen in the transition zone between vital liver parenchyma and cell death areas. Furthermore, the application of tunicamycin during reperfusion inhibited the secretion of pro-inflammatory cytokines and increased the hepatocellular damage significantly. However, the injection of TUDCA resulted in a significantly reduced liver damage, as seen by lower transaminases and smaller cell death areas. CONCLUSION: ER stress modulation influences post-hemorrhagic IRI. Moreover, the ER stress inhibitor TUDCA diminished the hepatocellular damage following HS/R significantly. This may help to provide a therapeutic target to ameliorate the clinical outcome after trauma-hemorrhage.

A computational analysis of dynamic, multi-organ inflammatory crosstalk induced by endotoxin in mice.

Bacterial lipopolysaccharide (LPS) induces an acute inflammatory response across multiple organs, primarily via Toll-like receptor 4 (TLR4). We sought to define novel aspects of the complex spatiotemporal dynamics of LPS-induced inflammation using computational modeling, with a special focus on the timing of pathological systemic spillover. An analysis of principal drivers of LPS-induced inflammation in the heart, gut, lung, liver, spleen, and kidney to assess organ-specific dynamics, as well as in the plasma (as an assessment of systemic spillover), was carried out using data on 20 protein-level inflammatory mediators measured over 0-48h in both C57BL/6 and TLR4-null mice. Using a suite of computational techniques, including a time-interval variant of Principal Component Analysis, we confirm key roles for cytokines such as tumor necrosis factor-α and interleukin-17A, define a temporal hierarchy of organ-localized inflammation, and infer the point at which organ-localized inflammation spills over systemically. Thus, by employing a systems biology approach, we obtain a novel perspective on the time- and organ-specific components in the propagation of acute systemic inflammation.

Hepatic topographical changes of endoplasmic reticulum stress and unfolded protein response signaling after hemorrhagic shock and reperfusion.

BACKGROUND: Endoplasmic reticulum (ER) stress plays a crucial role in cell death decisions in context of various diseases. Although it is known that ER stress occurs in livers subjected to hemorrhagic shock and reperfusion (HS/R), there is no understanding about the influence of the liver architecture on ER stress and the activation of the unfolded protein response (UPR). MATERIALS AND METHODS: Mice were subjected to a pressure-controlled HS (30 ± 5 mmHg) for 90 min. Mice were sacrificed 2, 4, 6, 8, 10, 14, 18, and 24 h after shock induction. Plasma levels of inflammatory cytokines (IL-6, CXCL1, CXCL9, CXCL10, CCL2, CCL3) and transaminases were measured. Hematoxylin and eosin stains of paraffin-embedded liver tissue sections were evaluated for liver damage. Immunohistochemistry was used to analyze the hepatic topography of ER stress marker binding immunoglobulin protein and the activation of the three major pathways of the UPR. RESULTS: Compared with sham-operated mice, HS/R led to profound liver damage and an elevation of inflammatory cytokines. We found time-dependent topographical changes of ER stress in the livers. Furthermore, the three major pathways of the UPR represented by protein kinase RNA-like ER kinase, activating transcription factor 6, and inositol-requiring enzyme 1 were activated in differing ways dependent on the zonation within the liver acinus. CONCLUSIONS: These findings show that the liver architecture must be taken into account when investigating the role of ER stress and the UPR in ischemia-reperfusion injury after HS/R.

Toll-Like Receptor 4 on both Myeloid Cells and Dendritic Cells Is Required for Systemic Inflammation and Organ Damage after Hemorrhagic Shock with Tissue Trauma in Mice.

Trauma combined with hemorrhagic shock (HS/T) leads to systemic inflammation, which results in organ injury. Toll-like Receptor 4 (TLR4)-signaling activation contributes to the initiation of inflammatory pathways following HS/T but its cell-specific roles in this setting are not known. We assessed the importance of TLR4 on leukocytes of myeloid lineage and dendritic cells (DCs) to the early systemic inflammatory response following HS/T. Mice were subjected to HS/T and 20 inflammatory mediators were measured in plasma followed by Dynamic Bayesian Network (DBN) Analysis. Organ damage was assessed by histology and plasma ALT levels. The role of TLR4 was determined using TLR4-/-, MyD88-/-, and Trif-/- C57BL/6 (B6) mice, and by in vivo administration of a TLR4-specific neutralizing monoclonal antibody (mAb). The contribution of TLR4 expressed by myeloid leukocytes and DC was determined by generating cell-specific TLR4-/- B6 mice, including Lyz-Cre × TLR4loxP/loxP, and CD11c-Cre × TLR4loxP/loxP B6 mice. Adoptive transfer of bone marrow-derived TLR4+/+ or TLR4-/- DC into TLR4-/- mice confirmed the contribution of TLR4 on DC to the systemic inflammatory response after HS/T. Using both global knockout mice and the TLR4-blocking mAb 1A6 we established a central role for TLR4 in driving systemic inflammation. Using cell-selective TLR4-/- B6 mice, we found that TLR4 expression on both myeloid cells and CD11chigh DC is required for increases in systemic cytokine levels and organ damage after HS/T. We confirmed the capacity of TLR4 on CD11chigh DC to promote inflammation and liver damage using adoptive transfer of TLR4+/+ conventional (CD11chigh) DC into TLR4-/- mice. DBN inference identified CXC chemokines as proximal drivers of dynamic changes in the circulating levels of cytokines/chemokines after HS/T. TLR4 on DC was found to contribute selectively to the elevations in these proximal drivers. TLR4 on both myeloid cells and conventional DC is required for the initial systemic inflammation and organ damage in a mouse model of HS/T. This includes a role for TLR4 on DC in promoting increases in the early inflammatory networks identified in HS/T. These data establish DC along with macrophages as essential to the recognition of tissue damage and stress following tissue trauma with HS.

The treatment of nonunions with application of BMP-7 increases the expression pattern for angiogenic and inflammable cytokines: a matched pair analysis.

The local application of bone morphogenetic protein-7 (BMP-7) in combination with the transplantation of autologous bone graft improves the outcome in nonunion treatment; however, the specific reasons remain unclear. In this study, we sought to determine if the local application of BMP-7 contributes to improved bone regeneration in nonunion therapy by modulation of the angiogenic and inflammable cytokine expression patterns of the early inflammation response. Therefore, we utilized the analysis of serological cytokine expression patterns. As a matched pair analysis, best-fitting patients who were treated with transplantation of autologous bone graft (G1, n=10) were compared with patients who were treated with additional application of BMP-7 (G2, n=10). The changes in the cytokine expression patterns were monitored and correlated to clinical data of bone healing. Significant differences in angiogenesis potential (vascular endothelial growth factor [VEGF] serum levels) could be found in the first days after surgery (P<0.05). Furthermore, the increase and absolute amount of VEGF levels in the BMP-7 group were considerably higher than in the control group during the first 2 weeks after surgery. The expression pattern of inflammable cytokines showed noticeable differences in the time point of significant elevated levels, in particular, inflammable cytokines showed an earlier peak in G2. Furthermore, interleukin-6 was significantly elevated within the first week only, comparing G2 to G1 (P<0.05). Our findings indicate that BMP-7 induces an early and more intense expression of VEGF via a direct and postulated indirect pathway, thereby providing a favorable environment for bone healing. Moreover, application of BMP-7 leads to an earlier expression of known proinflammatory cytokines. The results of this study show that application of BMP-7 leads to costimulatory effect on both angiogenic and inflammable cytokine expression patterns that may serve as a possible stimulus for bone regeneration.

Tlr2 on Bone Marrow and Non-Bone Marrow Derived Cells Regulates Inflammation and Organ Injury in Cooperation with Tlr4 During Resuscitated Hemorrhagic Shock.

BACKGROUND: Although the role of TLR4 in driving inflammation and organ injury after hemorrhagic shock and resuscitation (H/R) is well established, the role of TLR2-another receptor for damage-associated molecular pattern (DAMP) molecules-is not. In this study, we used a combination of TLR2 and wild type (WT) mice treated with anti-TLR2 and anti-TLR4 neutralizing monoclonal antibodies (mAb) to discern the contribution of TLR2 relative to TLR4 to the systemic inflammatory response in murine H/R. MATERIAL AND METHODS: WT mice, TLR2, and WT mice receiving an anti-TLR2 or an anti-TLR4 mAB (given as a pretreatment) were sacrificed at 6 or 20 h post-H/R. Bone marrow TLR2/WT chimeric mice were created to assess the importance of immune and nonimmune cell-associated TLR2. RESULTS: TLR2 mice subjected to H/R exhibited significantly less liver damage and lower markers of systemic inflammation only at 20 h. Bone marrow chimeric mice using combinations of TLR2 mice and WT mice demonstrated that TLR2 on non-bone marrow derived cells played a dominant role in the differences at 20 h. Interestingly, WT mice treated with anti-TLR2 mAB demonstrated a reduction in organ damage and systemic inflammation at both 6 and 20 h following H/R. A combination of anti-TLR2 mAB and anti-TLR4 mAB showed that both receptors drive IP-10 and KC levels and that there is cooperation for increases in IL-6, MIG, and MCP-1 levels between TLR2 and TLR4. CONCLUSION: These data also support the conclusion that TLR2 and TLR4 act in concert as important receptors in the host immune response to H/R.

Validity of subjective smoking status in orthopedic patients.

PURPOSE: In this level 1 diagnostic study, we analyzed the validity of subjective smoking status and, as secondary research question, the smoking cessation adherence in orthopedic patients during a routine hospital stay of nonunion patients by measuring serum cotinine. METHODS: We included patients undergoing revision surgery due to nonunion of long bones. Patients were interviewed about their smoking status. Blood samples were taken from all the patients prior to surgery and for an additional 6 weeks following surgery. Serum levels of cotinine were measured, and coherence between subjective smoking status and objective cotinine analysis was evaluated. RESULTS: Between March 2012 and August 2014, we enrolled 136 patients. Six of the 26 "previous smokers" (23%) and four of the 65 "nonsmokers" (6%) had serum cotinine above cutoff levels. In self-labeled smokers, serum cotinine levels averaged at 2,367.4±14,885.9 ng/mL (with a median of 100 ng/mL), whereas in previous smokers the levels averaged at 4,270±19,619.4 ng/mL (with a median of 0 ng/mL) and in the nonsmokers group the levels averaged at 12±53.9 ng/mL (with a median of 0.03 ng/mL). Overall, the subjective smoking status matched serum cotinine testing in 88% of the cases. Sensitivity was 79.6% and specificity was 93.1%. Ninety-one percent of the patients with preoperative positive serum values were still positive at follow-up. CONCLUSION: In this study, we could show that subjective smoking status in orthopedic patients is predominantly reliable as validated by objective cotinine measurements; however, patients who declare themselves as "previous smokers" are at elevated risk for underreporting continued smoking and patients who smoked preoperatively are at high risk for continuing their habit. In the future, caregivers should consider introducing effective treatments for smoking cessation to smokers and furthermore offer effective treatments to maintain smoking cessation in previous smokers during their routine consultation prior to orthopedic and trauma surgery.

Serum sCD95L concentration in patients with spinal cord injury.

OBJECTIVE: To determine serum concentrations of soluble CD95 ligand (sCD95L) in patients with traumatic spinal cord injury. METHODS: Patients with traumatic spinal cord injury were recruited. Blood was collected on admission to hospital and at 4 h, 9 h, 12 h, 24 h, 3 days, 7 days, and 2, 4, 8 and 12 weeks postadmission. Serum concentrations of sCD95L were determined via immunoassay. RESULT: The study included 23 patients. Mean sCD95L concentrations were significantly lower at 4 h, 9 h, 12 h and 24 h than at admission, and were significantly higher at 8 and 12 weeks, compared with admission. CONCLUSION: The serum sCD95L concentration fell significantly during the first 24 h after traumatic spinal cord injury. Concentrations then rose, becoming significantly higher than admission levels at 8 weeks. sCD95L may represent a possible therapeutic target for traumatic spinal cord injury.

Delayed neutralization of interleukin 6 reduces organ injury, selectively suppresses inflammatory mediator, and partially normalizes immune dysfunction following trauma and hemorrhagic shock.

An excessive and uncontrolled systemic inflammatory response is associated with organ failure, immunodepression, and increased susceptibility to nosocomial infection following trauma. Interleukin 6 (IL-6) plays a particularly prominent role in the host immune response after trauma with hemorrhage. However, as a result of its pleiotropic functions, the effect of IL-6 in trauma and hemorrhage is still controversial. It remains unclear whether suppression of IL-6 after hemorrhagic shock and trauma will attenuate organ injury and immunosuppression. In this study, C57BL/6 mice were treated with anti-mouse IL-6 monoclonal antibody immediately prior to resuscitation in an experimental model combining hemorrhagic shock and lower-extremity injury. Interleukin 6 levels and signaling were transiently suppressed following administrations of anti-IL-6 monoclonal antibody following hemorrhagic shock and lower-extremity injury. This resulted in reduced lung and liver injury, as well as suppression in the levels of key inflammatory mediators including IL-10, keratinocyte-derived chemokine, monocyte chemoattractant protein 1, and macrophage inhibitory protein 1α at both 6 and 24 h. Furthermore, the shift to TH2 cytokine production and suppressed lymphocyte response were partly prevented. These results demonstrate that IL-6 is not only a biomarker but also an important driver of injury-induced inflammation and immune suppression in mice. Rapid measurement of IL-6 levels in the early phase of postinjury care could be used to guide IL-6-based interventions.

Eritoran attenuates tissue damage and inflammation in hemorrhagic shock/trauma.

BACKGROUND: Severe injury and associated hemorrhagic shock lead to an inflammatory response and subsequent increased tissue damage. Numerous reports have shown that injury-induced inflammation and the associated end-organ damage is driven by Toll-like receptor 4 (TLR4) activation via damage-associated molecular patterns. We examined the effectiveness of Eritoran tetrasodium (E5564), an inhibitor of TLR4 function, in reducing inflammation induced during hemorrhagic shock with resuscitation (HS/R) or after peripheral tissue injury (bilateral femur fracture, BFF). MATERIAL AND METHODS: Mice underwent HS/R or BFF with or without injection of Eritoran (5 mg/kg body weight) or vehicle control given before, both before and after, or only after HS/R or BFF. Mice were sacrificed after 6 h and plasma and tissue cytokines, liver damage (histology; aspartate aminotransferase/alanine aminotransferase), and inflammation (NF-κB) and gut permeability were assessed. RESULTS: In HS/R Eritoran significantly reduced liver damage (values ± SEM: alanine aminotransferase 9910 ± 3680 U/L versus 1239 ± 327 U/L and aspartate aminotransferase 5863 ± 2000 U/L versus 1246 ± 243 U/L, P < 0.01) at 6 h compared with control when given just before HS and again just prior to resuscitation. Eritoran administration also led to lower IL-6 levels in plasma and liver and less NF-κB activation in liver. Increases in gut barrier permeability induced by HS/R were also prevented with Eritoran. Eritoran similarly diminished BFF-mediated systemic inflammatory responses. CONCLUSION: These data suggest Eritoran can inhibit tissue damage and inflammation induced via TLR4/myeloid differentiation factor 2 signaling from damage-associated molecular patterns released during HS/R or BFF. Eritoran may represent a promising therapeutic for trauma patients to prevent multiple organ failure.

CD14 contributes to warm hepatic ischemia-reperfusion injury in mice.

INTRODUCTION: Ischemia/reperfusion (I/R) of the liver contributes to the pathobiology of liver injury in transplantation, liver surgery, and hemorrhagic shock. Ischemia/reperfusion induces an inflammatory response that is driven, in part, by Toll-like receptor 4 (TLR) signaling. CD14 is known to participate in the function of TLR4. We hypothesized that CD14 would be involved in the pathobiology of warm hepatic I/R. METHODS: Using a 70% liver inflow inclusion model, CD14 knockout and wild-type (WT) mice were subjected to 1-h warm ischemia followed by reperfusion. CD14 mRNA, circulating transaminase, interleukin 6, soluble CD14, and high-mobility group box 1 (HMGB1) levels were measured. CD14 neutralizing antibody or isotype control antibody was given before ischemia or reperfusion for CD14 blockade in WT mice. Recombinant HMGB1 was given before reperfusion in some experiments to test if liver injury worsens. RESULTS: There was an upregulation of CD14 mRNA in reperfused livers together with increased soluble CD14 levels in the circulation. Compared with WT control mice, CD14 knockout mice had much lower alanine aminotransferase and interleukin 6 levels at 6 and 24 h following I/R, and much less liver necrosis by histology. TUNEL (terminal deoxynucleotidyl-transferase dUTP nick end labeling) staining displayed less apoptosis at 24 h in the absence of CD14. CD14 blockage by neutralizing antibody also attenuated liver injury and the inflammatory response in C57BL/6 mice following I/R, but did not provide additional protection to TLR4 mutant C3H/Hej mice. CD14 deficiency did not change circulating HMGB1 levels following I/R (6 h). A dose of recombinant HMGB1, which worsened hepatic injury when given before reperfusion in WT mice, did not increase liver damage in CD14-deficient mice. CONCLUSIONS: CD14 is actively involved in hepatic I/R injury. Its deficiency or blockade ischemia attenuates liver injury and inflammatory response. CD14 mediates liver damage and inflammatory responses in the setting of warm hepatic I/R in mice.

Cellular-specific role of toll-like receptor 4 in hepatic ischemia-reperfusion injury in mice.

UNLABELLED: Ischemia-reperfusion (I/R) injury is a process whereby an initial hypoxic insult and subsequent return of blood flow leads to the propagation of innate immune responses and organ injury. The necessity of the pattern recognition receptor, Toll-like receptor (TLR)4, for this innate immune response has been previously shown. However, TLR4 is present on various cell types of the liver, both immune and nonimmune cells. Therefore, we sought to determine the role of TLR4 in individual cell populations, specifically, parenchymal hepatocytes (HCs), myeloid cells, including Kupffer cells, and dendritic cells (DCs) subsequent to hepatic I/R. When HC-specific (Alb-TLR4(-/-) ) and myeloid-cell-specific (Lyz-TLR4(-/-) ) TLR4 knockout (KO) mice were subjected to warm hepatic ischemia, there was significant protection in these mice, compared to wild type (WT). However, the protection afforded in these two strains was significantly less than global TLR4 KO (TLR4(-/-) ) mice. DC-specific TLR4(-/-) (CD11c-TLR4(-/-) ) mice had significantly increased hepatocellular damage, compared to WT mice. Circulating levels of high-mobility group box 1 (HMGB1) were significantly reduced in Alb-TLR4(-/-) mice, compared to WT, Lyz-TLR4(-/-) , CD11c-TLR4(-/-) mice and equivalent to global TLR4(-/-) mice, suggesting that TLR4-mediated HMGB1 release from HCs may be a source of HMGB1 after I/R. HCs exposed to hypoxia responded by rapidly phosphorylating the mitogen-activated protein kinases, c-Jun-N-terminal kinase (JNK) and p38, in a TLR4-dependent manner; inhibition of JNK decreased release of HMGB1 after both hypoxia in vitro and I/R in vivo. CONCLUSION: These results provide insight into the individual cellular response of TLR4. The parenchymal HC is an active participant in sterile inflammatory response after I/R through TLR4-mediated activation of proinflammatory signaling and release of danger signals, such as HMGB1.

Time dependency and topography of hepatic nuclear factor κB activation after hemorrhagic shock and resuscitation in mice.

The leading causes of death in people aged 1 to 44 years are unintentional injuries with associated hemorrhagic shock. Hemorrhagic shock followed by resuscitation (H/R) activates the nuclear factor κB (NF-κB) pathway. To further address the association between liver damage and NF-κB activation, we analyzed the H/R-induced activation of NF-κB using cis-NF-κB reporter gene mice. In these mice, the expression of green fluorescent protein (GFP) is linked to the activation of NF-κB, and therefore tracing of GFP colocalizes NF-κB activation. Mice were hemorrhaged to a mean arterial blood pressure of 30mmHg for 90 min, followed by resuscitation. Six, 14, or 24 h after resuscitation, mice were killed. Compared with sham-operated mice, H/R led to a profound hepatic and cellular damage as measured by aspartate aminotransferase, creatine kinase, and lactate dehydrogenase levels, which was accompanied by an elevation in interleukin 6 levels and hepatic leukocyte infiltration. Interleukin 10 levels in plasma were elevated 6 h after H/R. Using serial liver sections, we found an association between necrotic areas, oxidative stress, and enhanced GFP-positive cells. Furthermore, enhanced GFP-positive cells surrounded areas of necrotic liver tissue, predominantly in a penumbra-like-shape pericentrally. These results elucidate spatial relationship between oxidative stress, liver necrosis, and NF-κB activation, using an in vivo approach and therefore might help to further analyze mechanisms of NF-κB activation after resuscitated blood loss.

Mast cells play a critical role in the systemic inflammatory response and end-organ injury resulting from trauma.

BACKGROUND: Much of the morbidity after trauma results from excessive activation of the innate immune system. This is manifested as a systemic inflammatory response and associated end-organ damage. Although mast cells are known to be important in many immune responses, their role in the systemic response to severe trauma is unknown. STUDY DESIGN: C57BL/6J-KitW-sh/BsmJ (mast cell deficient) and wild type mice were subjected to 1.5 hours of hemorrhagic shock plus bilateral femur fracture and soft tissue injury (HS/T), followed by resuscitation at 4.5 hours. Blood withdrawal volumes, mean arterial pressures, circulating cytokine, chemokine, high mobility group box-1 (HMGB-1), double strain DNA (dsDNA), transaminase levels, and histology in liver and lung were compared between groups. RESULTS: Mast cell deficient mice exhibited greater hemodynamic stability than wild type mice. At baseline, the mast cell deficient mice exhibited no difference in any of the organ injury or inflammatory markers measured. As expected, wild type mice subjected to HS/T exhibited end-organ damage manifested by marked increases in circulating alanine transaminase, aspartate aminotransferase, and dsDNA levels, as well as histologic evidence of tissue necrosis. In clear contrast, mast cell deficient mice exhibited almost no tissue damage. Similarly, the magnitude of increased circulating cytokine and chemokine induced by HS/T was much less in the mast cell deficient mice than in the wild type group. CONCLUSIONS: Mast cell deficiency resulted in a damped systemic inflammatory response, greatly attenuated multiple organ injury, and more stable hemodynamics in HS/T. So mast cells appear to be a critical component of the initial host response to severe injury.

SelTarbase, a database of human mononucleotide-microsatellite mutations and their potential impact to tumorigenesis and immunology.

About 15% of human colorectal cancers and, at varying degrees, other tumor entities as well as nearly all tumors related to Lynch syndrome are hallmarked by microsatellite instability (MSI) as a result of a defective mismatch repair system. The functional impact of resulting mutations depends on their genomic localization. Alterations within coding mononucleotide repeat tracts (MNRs) can lead to protein truncation and formation of neopeptides, whereas alterations within untranslated MNRs can alter transcription level or transcript stability. These mutations may provide selective advantage or disadvantage to affected cells. They may further concern the biology of microsatellite unstable cells, e.g. by generating immunogenic peptides induced by frameshifts mutations. The Selective Targets database (http://www.seltarbase.org) is a curated database of a growing number of public MNR mutation data in microsatellite unstable human tumors. Regression calculations for various MSI-H tumor entities indicating statistically deviant mutation frequencies predict TGFBR2, BAX, ACVR2A and others that are shown or highly suspected to be involved in MSI tumorigenesis. Many useful tools for further analyzing genomic DNA, derived wild-type and mutated cDNAs and peptides are integrated. A comprehensive database of all human coding, untranslated, non-coding RNA- and intronic MNRs (MNR_ensembl) is also included. Herewith, SelTarbase presents as a plenty instrument for MSI-carcinogenesis-related research, diagnostics and therapy.

Frameshift mutations in coding repeats of protein tyrosine phosphatase genes in colorectal tumors with microsatellite instability.

BACKGROUND: Protein tyrosine phosphatases (PTPs) like their antagonizing protein tyrosine kinases are key regulators of signal transduction thereby assuring normal control of cellular growth and differentiation. Increasing evidence suggests that mutations in PTP genes are associated with human malignancies. For example, mutational analysis of the tyrosine phosphatase (PTP) gene superfamily uncovered genetic alterations in about 26% of colorectal tumors. Since in these studies tumors have not been stratified according to genetic instability status we hypothesized that colorectal tumors characterized by high-level of microsatellite instability (MSI-H) might show an increased frequency of frameshift mutations in those PTP genes that harbor long mononucleotide repeats in their coding region (cMNR). RESULTS: Using bioinformatic analysis we identified 16 PTP candidate genes with long cMNRs that were examined for genetic alterations in 19 MSI-H colon cell lines, 54 MSI-H colorectal cancers, and 17 MSI-H colorectal adenomas. Frameshift mutations were identified only in 6 PTP genes, of which PTPN21 show the highest mutation frequency at all in MSI-H tumors (17%). CONCLUSION: Although about 32% of MSI-H tumors showed at least one affected PTP gene, and cMNR mutation rates in PTPN21, PTPRS, and PTPN5 are higher than the mean mutation frequency of MNRs of the same length, mutations within PTP genes do not seem to play a common role in MSI tumorigenesis, since no cMNR mutation frequency reached statistical significance and therefore, failed prediction as a Positive Selective Target Gene.