Interferon-gamma is a therapeutic target molecule for prevention of postoperative adhesion formation

Data mining of atherosclerotic plaque transcriptomes predicts STAT1-dependent inflammatory signal integration in vascular disease

Atherosclerotic plaque development involves multiple extra- and intra-cellular signals engaging cells from the immune system and from the vasculature. Pro-inflammatory pathways activated by interferon gamma (IFNγ) and toll-like receptor 4 (TLR4) ligands are profoundly involved in plaque formation and have been shown to involve cross-talk in all atheroma-interacting cell types leading to increased activation of signal transducer and activator of transcription-1 (STAT1) and elevated expression of pro-inflammatory mediators. Here we demonstrate that in Gene Expression Omnibus repository (GEO) deposited microarray datasets, obtained from human coronary and carotid atherosclerotic plaques, a significant increase in expression of pro-inflammatory and immunomodulatory genes can be detected. Moreover, increased expression of multiple chemokines, adhesion molecules and matrix-remodeling molecules was commonly detected in both plaque types and correlated with the presence of putative STAT1 binding sites in their promoters, suggesting strong involvement of STAT1 in plaque development. We also provide evidence to suggest that STAT1-nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) or STAT1-interferon-regulated factor (IRF) regulatory modules are over-represented in the promoters of these inflammatory genes, which points to a possible contribution of IFNγ and TLR4 cross-talk in the process of atherogenesis. Finally, a subset of these genes encodes for secreted proteins that could serve as a basis of a non-invasive diagnostic assay. The results of our in silico analysis in vitro provide potential evidence that STAT1-dependent IFNγ-TLR4 cross-talk plays a crucial role in coronary and carotid artery plaque development and identifies a STAT1-dependent gene signature that could represent a novel diagnostic tool to monitor and diagnose plaque progression in human atherosclerosis.

The neurokinin 1 receptor regulates peritoneal fibrinolytic activity and postoperative adhesion formation

BACKGROUND

Intra-abdominal adhesions are a common source of postoperative morbidity. Previous studies in our laboratory have shown that a neurokinin 1 receptor antagonist (NK-1RA) reduces abdominal adhesion formation and increases peritoneal fibrinolytic activity. However, the cellular pathway by which the antagonist exerts its effects is unclear, as cultured peritoneal mesothelial cells exposed to the NK-1RA show increases in fibrinolytic activity despite having very low expression of neurokinin 1 receptor (NK-1R) messenger RNA and protein. Our aim was to determine whether the NK-1R plays an essential role in the adhesion-reducing effects of the NK-1RA, or if the NK-1RA is acting independently of the receptor.

METHODS

Homozygous NK-1R knockout mice and age matched wild-type mice underwent laparotomy with cecal cautery to induce adhesions. At the time of surgery, mice received a single intraperitoneal dose of either NK-1RA (25 mg/kg) or saline alone. Adhesion severity at the site of cecal cautery was assessed on postoperative day 7. In a separate experiment, peritoneal fluid was collected from wild type and NK-1R knockout mice 24 h after laparotomy with cecal cautery and administration of either NK-1RA or saline. Tissue plasminogen activator levels, representative of total fibrinolytic activity, were then measured in peritoneal fluid.

RESULTS

In wild-type mice, NK-1RA administration significantly decreased adhesion formation compared with saline controls. Among the NK-1R knockout mice, there was no significant reduction in adhesion formation by the NK-1RA. Fibrinolytic activity increased 244% in wild-type mice administered NK-1RA compared with saline controls; however, the NK-1RA did not raise fibrinolytic activity above saline controls in NK-1R knockout mice.

CONCLUSIONS

These data indicate that the NK-1R mediates the adhesion-reducing effects of the NK-1RA, in part, by the upregulation of peritoneal fibrinolysis, and suggest that the NK-1R is a promising therapeutic target for adhesion prevention.

Interferon γ and plasminogen activator inhibitor 1 regulate adhesion formation after partial hepatectomy

BACKGROUND

The pathophysiology of intra-abdominal adhesions has not been studied extensively. The aim of this study was to elucidate the molecular mechanisms underlying adhesion formation in a murine model and in patients undergoing hepatectomy.

METHODS

Partial hepatectomy was performed using bipolar forceps in mice. Wild-type mice, antibodies to CD4 and interferon (IFN) γ, IFN-γ, natural killer T (NKT) cells and plasminogen activator inhibitor (PAI) 1 knockout (KO) mice were used. Recombinant hepatocyte growth factor (HGF) was tested for its ability to prevent adhesions. Liver specimens were obtained during surgery from patients undergoing hepatectomy. Adhesion formation was evaluated using a scoring system that ranged from 0 (no adhesions) to 5 (severe adhesions). Levels of IFN-γ and PAI-1 mRNA, and protein concentration of PAI-I were measured, and fluorescence immunostaining was performed.

RESULTS

Adhesion formation depended on IFN-γ produced by NKT cells, and NKT KO mice developed few adhesions (mean(s.d.) 1·7(0·3) versus 4·6(0·4) in wild-type mice; P = 0·037). In wild-type mice, the level of PAI-1 mRNA increased after hepatectomy, followed by a decrease in the tissue plasminogen activator (tPA) mRNA level. Adhesion formation was inhibited completely in PAI-1 KO mice (0(0) versus 4·1(0·8) in wild-type mice; P = 0·002). HGF inhibited formation of abdominal adhesions after hepatectomy by reducing IFN-γ and PAI-1 levels, and increasing tPA levels compared with those in mice treated with phosphate-buffered saline (P < 0·001, P = 0·002 and P = 0·035 respectively). In human liver specimens, NKT cells accumulated in the liver after hepatectomy, and PAI-1 expression was increased 5·25-fold (P = 0·030).

CONCLUSION

IFN-γ is a key molecule for abdominal adhesion formation after hepatectomy, acting via the reciprocal balance of PAI-1 and tPA. This molecular mechanism may also regulate adhesion formation in patients following hepatectomy. HGF inhibited formation of adhesions by regulating IFN-γ and PAI-1, suggesting that it may be an important target for prevention of adhesions after hepatectomy. SURGICAL RELEVANCE: Postoperative intra-abdominal adhesions can be asymptomatic or cause significant morbidity and mortality. Adhesion formation after hepatectomy has not been studied extensively. In the present study, the molecular mechanisms underlying intra-abdominal adhesions after hepatectomy were investigated in a murine model and in patients. Interferon (IFN) γ produced by natural killer T cells is a key molecule for adhesion formation after hepatectomy in mice, acting via the reciprocal balance between plasminogen activator inhibitor (PAI) 1 and tissue plasminogen activator, the pivotal factors in fibrinolytic activity. This mechanism was also involved in the regulation of adhesions in human tissue samples. Hepatocyte growth factor (HGF) strongly inhibited adhesion formation by regulating IFN-γ and PAI-1. These results indicate that IFN-γ and PAI-1 are possible therapeutic targets, and HGF could prevent postoperative adhesion formation after hepatectomy.

Berberine hydrochloride prevents postsurgery intestinal adhesion and inflammation in rats

Intestinal adhesion, characterized by connection of the loops of the intestine with other abdominal organs by fibrous tissue bands, remains an inevitable event of abdominal operations and can cause a number of complications. Berberine hydrochloride (berberine), a natural plant alkaloid derived from Chinese herbal medicine, is characterized by diverse pharmacological effects, such as anticancer and lower elevated blood glucose. This study is designed to investigate the effects of berberine on adhesion and inflammation after abdominal surgeries and the underlying molecular mechanisms. Adhesion severity grades and collagen deposition were assessed 14 days after surgery. We evaluated the levels of intercellular adhesion molecule-1 (ICAM-1) and inflammatory cytokines interleukin-1β (IL-1β), IL-6, transforming growth factor β (TGF-β), tumor necrosis factor-α (TNF-α), and examined transforming growth factor-activated kinase 1 (TAK1)/c-Jun N-terminal kinase (JNK) and TAK1/nuclear factor κB (NF-κB) signaling. The surgery group experienced the most severe adhesions, and berberine strikingly reduced the density and severity of adhesion. Results showed significant lower expression of IL-1β, IL-6, TGF-β, TNF-α, and ICAM-1, in berberine groups compared with the operation group. Activities of phosphorylated JNK and phosphorylated NF-κB were inhibited in the berberine groups compared with the surgery group. Our novel findings identified berberine hydrochloride as a promising strategy to prevent adhesion by downregulating ICAM-1 and reduce inflammation by inhibiting the TAK1/JNK and TAK1/NF-κB signaling after abdominal surgery, which brought out a good therapeutic approach for the development of clinical application for postoperative abdominal adhesion and inflammation.

Peritoneal cell sheets composed of mesothelial cells and fibroblasts prevent intra-abdominal adhesion formation in a rat model

Postoperative intra-abdominal adhesions remain an unsolved problem despite significant progress in the surgical procedures themselves. They often lead to small-bowel obstruction, chronic abdominal and pelvic pain, as well as female infertility. The loss of mesothelial cells and several components of the inflammatory system following injury to the peritoneum results in fibrin formation and angiogenesis. The remaining fibrin matrix and angiogenesis lead to replacement by fibroblasts and fibrous band formation. The aim of this study was to develop a new therapeutic method of preventing intra-abdominal adhesions. We fabricated transplantable peritoneal cell sheets from the rat peritoneum by cell sheet engineering using a temperature-responsive culture system. The peritoneal cell sheets developed were composed of an upper monolayer of mesothelial cells and underlying multilayered fibroblasts, similar to the peritoneum in vivo. Transplantation of peritoneal cell sheets prevented tissue adhesion, fibrin deposition and angiogenesis, and, moreover, lymphangiogenesis and macrophage infiltration in a rat caecum cauterization adhesion model. Copyright © 2013 John Wiley & Sons, Ltd.

Novel thermosensitive hydrogel for preventing formation of abdominal adhesions

Adhesions can form after almost any type of abdominal surgery. Postoperative adhesions can be prevented by improved surgical techniques, such as reducing surgical trauma, preventing ischemia, and avoiding exposure of the peritoneal cavity to foreign materials. Although improved surgical techniques can potentially reduce formation of adhesions, they cannot be eliminated completely. Therefore, finding more effective methods to prevent postoperative adhesions is imperative. Recently, we found that a novel thermosensitive hydrogel, ie, poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) had the potential to prevent postoperative adhesions. Using the ring-opening polymerization method we prepared a PCEC copolymer which could be dissolved and assembled at 55°C into PCEC micelles with mean size of 25 nm. At body temperature, a solution containing PCEC micelles could convert into a hydrogel. The PCEC copolymer was biodegradable and had low toxicity in vitro and in vivo. We found that most animals in a hydrogel-treated group (n = 10) did not develop adhesions. In contrast, 10 untreated animals developed adhesions that could only be separated by sharp dissection (P < 0.001). The hydrogel could adhere to peritoneal wounds and degraded gradually over 7-9 days, transforming into a viscous fuid that was completely absorbed within 12 days. The injured parietal and visceral peritoneum remesothelialized over about seven and nine days, respectively. This study confirms that PCEC hydrogel has potential application in the prevention of postoperative adhesions.

Preservation of peritoneal fibrinolysis owing to decreased transcription of plasminogen activator inhibitor-1 in peritoneal mesothelial cells suppresses postoperative adhesion formation in laparoscopic surgery

BACKGROUND

Postoperative adhesion formation is regulated by peritoneal fibrinolysis, which is determined by tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). This study compared peritoneal fibrinolysis and adhesion formation after laparoscopic surgery (LAP) and open surgery (OP).

METHODS

We divided 154 male rats into 3 groups after cecal cauterization: Control, no treatment; LAP, CO2 pneumoperitoneum at 5 mmHg for 60 minutes; and OP, laparotomy for 60 minutes. Adhesions were quantified at day 7. The activity and mRNA level of tPA and PAI-1 were determined by enzyme-linked immunosorbent assay in plasma and peritoneal lavage and by real-time polymerase chain reaction in peritoneal mesothelial cells from omentum. We also examined peritoneal fibrinolysis in human gastric cancer patients treated with LAP (n = 14) or OP (n = 10).

RESULTS

In the animal study, adhesion scores, PAI-1 activity in peritoneal lavage fluid, and PAI-1 mRNA levels in peritoneal mesothelium were significantly greater in the OP group than the control and LAP groups. In the human study, postoperative PAI-1 mRNA levels were significantly greater in the OP group than the LAP group. Additionally, PAI-1 mRNA levels and subsequent adhesion formation were induced by prolonged operative time in the OP group, but not the LAP group.

CONCLUSION

Preservation of peritoneal fibrinolysis owing to decreased PAI-1 expression at the transcriptional level in peritoneal mesothelial cells is associated with suppression of postoperative adhesion formation in LAP. PAI-1 mRNA levels and subsequent adhesion formation were not induced by prolonged operative time in LAP. These results highlight the less invasiveness nature of LAP.

Comprehensive analysis of chemokines and cytokines secreted in the peritoneal cavity during laparotomy

We recently found that chemokine-driven peritoneal cell aggregation is the primary mechanism of postoperative adhesion in a mouse model. To investigate this in humans, paired samples of peritoneal lavage fluid were obtained from seven patients immediately after incision (preoperative) and before closure (postoperative), and were assayed for the presence of 27 cytokines and chemokines using multiplex beads assay. As a result, IL-6 and CCL5 showed the most striking increase during operation. Recombinant CCL5 or lavage fluid induced chemotaxis of human peripheral blood mononuclear cells. We propose that CCL5 is possibly involved in the mechanism of postoperative adhesion in humans.

Adhesion prevention in patients with multiple cesarean deliveries

Adhesion formation is a well-known complication of abdominal surgery. Although one third of all deliveries in the United States are by cesarean delivery (CD), little is known about adhesions in the obstetric setting. Various surgical techniques for reducing adhesion formation following CD have been investigated. The relative benefits of peritoneal closure and single-layer uterine closure are areas of continued research and debate. Adhesion prevention products are also becoming more commonplace in gynecologic surgery. Two membrane/adhesion barriers have been approved in the United States. A barrier consisting of oxidized regenerated cellulose (Interceed absorbable adhesion barrier) has been shown to reduce adhesions during microsurgery. Its use may be limited following CD because complete hemostasis is crucial to its efficacy. Seprafilm adhesion barrier, composed of hyaluronic acid and carboxymethylcellulose, is approved for use in abdominal or pelvic laparotomy. Preliminary data suggest that it may be effective for reducing adhesions following CD. This article discusses what is currently known about adhesion prevention in the obstetric population and highlights the paucity of level I evidence available to clinicians in this setting.

Prevention of NKT cell activation accelerates cutaneous wound closure and alters local inflammatory signals

We previously reported that in the absence of NKT cells, wound closure was accelerated in a murine excisional punch wound model. Here, we explored whether purposefully inhibiting NKT cell activation had similar effects on wound closure and the dermal inflammatory response to injury. We found that prevention of NKT cell activation accelerated wound closure in a dose-responsive manner. If anti-CD1d was administered before wounding, NKT cell infiltration into cutaneous wounds was diminished without quantitative changes in cellular infiltrates. Furthermore, prevention of NKT cell activation transiently enhanced the local production of a subset of chemokines, including MIP-2, MCP-1, MIP-1α, and MIP-1β, and altered the relative expression of CD69 and CXCR2 on the surface of both circulating and wound NKT cells. Taken together, these findings suggest that wounding activates NKT cells via CD1d presentation of glycolipid antigen and help further define a role for NKT cells in the regulation of wound inflammation and closure. Many soluble factors have been targeted as potential wound healing therapies, but their clinical success has been limited. Given our findings, the NKT cell may be an attractive target for wound healing therapies.

Inhibition of surgical trauma-enhanced peritoneal dissemination of tumor cells by human catalase derivatives in mice

Surgical trauma, which is inevitably associated with the surgical removal of cancer, has been reported to accelerate tumor metastasis. The close association of reactive oxygen species with the trauma and tumor metastasis supports the possibility of using antioxidants for the inhibition of metastasis. To inhibit surgical trauma-enhanced peritoneal dissemination, human catalase (hCAT) derivatives, i.e., hCAT-nona-arginine peptide (hCAT-R9) and hCAT-albumin-binding peptide (hCAT-ABP), were designed to increase the retention time of the antioxidant enzyme in the abdominal cavity after intraperitoneal administration. Both (125)I-labeled derivatives showed significantly prolonged retention in the cavity compared to (125)I-hCAT. Cauterization of the cecum of mice with a hot iron, an experimental model of surgical trauma, induced abdominal adhesions. In addition, cauterization followed by colon26 tumor cell inoculation increased lipid peroxidation in the cecum and mRNA expression of molecules associated with tissue repair/adhesion and inflammation in the peritoneum. hCAT derivatives significantly suppressed the increased mRNA expression. The cauterization also increased the number of tumor cells in the abdominal organs, and the number was significantly reduced by hCAT-R9 or hCAT-ABP. These results indicate that hCAT-R9 and hCAT-ABP, both of which have a long retention time in the peritoneal cavity, can be effective at inhibiting surgery-induced peritoneal metastasis.

Absence of IFN-γ accelerates thrombus resolution through enhanced MMP-9 and VEGF expression in mice

Deep vein thrombosis (DVT) is a major cause of pulmonary thromboembolism, a leading cause of death in individuals with DVT. Several lines of evidence indicate proinflammatory cytokines such as TNF-α are involved in thrombus formation and resolution, but the roles of IFN-γ remain unclear. To address this issue, we performed ligation of the inferior vena cava to induce DVT in WT and IFN-γ-deficient (Ifng-/-) mice. In WT mice, intrathrombotic IFN-γ levels were elevated progressively as the postligation interval was extended. Thrombus size was substantially smaller at 10 and 14 days in Ifng-/- mice than in WT mice. Intrathrombotic collagen content was remarkably reduced at more than 10 days after the ligation in Ifng-/- mice compared with WT mice. The expression and activity of MMP-9, but not MMP-2, was higher at the late phase in Ifng-/- mice than in WT mice. Moreover, intrathrombotic recanalization was increased in Ifng-/- mice, with enhanced Vegf gene expression, compared with that in WT mice. Activation of the IFN-γ/Stat1 signal pathway suppressed PMA-induced Mmp9 and Vegf gene expression in peritoneal macrophages. Furthermore, administration of anti-IFN-γ mAbs accelerated thrombus resolution in WT mice. Collectively, these findings indicate that IFN-γ can have detrimental roles in thrombus resolution and may be a good molecular target for the acceleration of thrombus resolution in individuals with DVT.

Adhesion awareness: a national survey of surgeons

Background

Postoperative adhesions are the most frequent complication of abdominal surgery, leading to high morbidity, mortality, and costs. However, the problem seems to be neglected by surgeons for largely unknown reasons.

Methods

A survey assessing knowledge and personal opinion about the extent and impact of adhesions was sent to all Dutch surgeons and surgical trainees. The informed-consent process and application of antiadhesive agents were questioned in addition.

Results

The response rate was 34.4%. Two thirds of all respondents (67.7%) agreed that adhesions exert a clinically relevant, negative effect. A negative perception of adhesions correlated with a positive attitude regarding adhesion prevention (ρ = 0.182, p < 0.001). However, underestimation of the extent and impact of adhesions resulted in low knowledge scores (mean test score 37.6%). Lower scores correlated with more uncertainty about indications for antiadhesive agents which, in turn, correlated with never having used any of these agents (ρ = 0.140, p = 0.002; ρ = 0.095, p = 0.035; respectively). Four in 10 respondents (40.9%) indicated that they never inform patients on adhesions and only 9.8% informed patients routinely. A majority of surgeons (55.9%) used antiadhesive agents in the past, but only a minority (13.4%) did in the previous year. Of trainees, 82.1% foresaw an increase in the use of antiadhesive agents compared to 64.5% of surgeons (p < 0.001).

Conclusions

The magnitude of the problem of postoperative adhesions is underestimated and informed consent is provided inadequately by Dutch surgeons. Exerting adhesion prevention is related to the perception of and knowledge about adhesions.

Prevention of post-surgical abdominal adhesions by a novel biodegradable thermosensitive PECE hydrogel

Background

Post-operative peritoneal adhesions are common and serious complications for modern medicine. We aim to prevent post-surgical adhesions using biodegradable and thermosensitive poly(ethylene glycol)-poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) hydrogel. In this work, we investigated the effect of PECE hydrogel on preventing post-surgical abdominal adhesions in mouse and rat models.

Results

The PECE hydrogel in sol state could be transformed into gel in less than 20 s at 37°C. In addition, the PECE hydrogel could be easily adhered to the damaged peritoneal surfaces, and be gradually degraded and absorbed by the body within 14 days along with the healing of peritoneal wounds. A notable efficacy of the PECE hydrogel in preventing peritoneal adhesions was demonstrated in the animal models. In contrast, all untreated animals developed adhesions requiring sharp dissection. Furthermore, no significant histopathological changes were observed in main organs of the hydrogel-treated animals.

Conclusion

Our results suggested that the thermosensitive PECE hydrogel was an effective, safe, and convenient agent on preventing post-surgical intro-abdominal adhesions.

Peritoneal damage: the inflammatory response and clinical implications of the neuro-immuno-humoral axis

BACKGROUND

The peritoneum is a bilayer serous membrane that lines the abdominal cavity. We present a review of peritoneal structure and physiology, with a focus on the peritoneal inflammatory response to surgical injury and its clinical implications.

METHODS

We conducted a nonsystematic clinical review. A search of the Ovid MEDLINE database from 1950 through January 2009 was performed using the following search terms: peritoneum, adhesions, cytokine, inflammation, and surgery.

RESULTS

The peritoneum is a metabolically active organ, responding to insult through a complex array of immunologic and inflammatory cascades. This response increases with the duration and extent of injury and is central to the concept of surgical stress, manifesting via a combination of systemic effects, and local neural pathways via the neuro-immuno-humoral axis. There may be a decreased systemic inflammatory response after minimally invasive surgery; however, it is unclear whether this is due to a reduced local peritoneal reaction.

CONCLUSIONS

Interventions that dampen the peritoneal response and/or block the neuro-immuno-humoral pathway should be further investigated as possible avenues of enhancing recovery after surgery, and reducing postoperative complications.

Anti-colitis and -adhesion effects of daikenchuto via endogenous adrenomedullin enhancement in Crohn's disease mouse model

BACKGROUND AND AIMS

Adrenomedullin (ADM) is a member of the calcitonin family of regulatory peptides, and is reported to have anti-inflammatory effects in animal models of Crohn's disease (CD). We investigated the therapeutic effects of daikenchuto (DKT), an extracted Japanese herbal medicine, on the regulation of endogenous ADM in the gastrointestinal tract in a CD mouse model.

METHODS

Colitis was induced in mice by intrarectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS); afterwards, DKT was given orally. Colonic damage was assessed on day 3 by macroscopic and microscopic observation, enzyme immunoassays of proinflammatory cytokines in the colonic mucosa, and serum amyloid A (SAA), a hepatic acute-phase protein. To determine the involvement of ADM, an ADM antagonist was instilled intrarectally before DKT administration. The effect of DKT on ADM production by intestinal epithelial cells was evaluated by enzyme immunoassay and real-time PCR.

RESULTS

DKT significantly attenuated mucosal damage and colonic inflammatory adhesions, and inhibited elevations of SAA in plasma and the proinflammatory cytokines TNFα and IFNγ in the colon. Small and large intestinal epithelial cells produced higher levels of ADM after DKT stimulation. A DKT-treated IEC-6 cell line also showed enhanced ADM production at protein and mRNA levels. Abolition of this effect by pretreatment with an ADM antagonist shows that DKT appears to exert its anti-colitis effect via up-regulation of endogenous ADM in the intestinal tract.

CONCLUSION

DKT exerts beneficial effects in a CD mouse model through endogenous release and production of ADM. Endogenous ADM may be a therapeutic target for CD.

Co-receptor choice by V alpha14i NKT cells is driven by Th-POK expression rather than avoidance of CD8-mediated negative selection

Mouse natural killer T (NKT) cells with an invariant Vα14-Jα18 rearrangement (Vα14 invariant [Vα14i] NKT cells) are either CD4⁺CD8⁻ or CD4⁻CD8⁻. Because transgenic mice with forced CD8 expression in all T cells exhibited a profound NKT cell deficit, the absence of CD8 has been attributed to negative selection. We now present evidence that CD8 does not serve as a coreceptor for CD1d recognition and that the defect in development in CD8 transgene homozygous mice is the result of a reduction in secondary T cell receptor α rearrangements. Thymocytes from mice hemizygous for the CD8 transgene have a less severe rearrangement defect and have functional CD8⁺ Vα14i NKT cells. Furthermore, we demonstrate that the transcription factor Th, Poxviruses and Zinc finger, and Krüppel family (Th-POK) is expressed by Vα14i NKT cells throughout their differentiation and is necessary both to silence CD8 expression and for the functional maturity of Vα14i NKT cells. We therefore suggest that Th-POK expression is required for the normal development of Vα14i NKT cells and that the absence of CD8 expression by these cells is a by-product of such expression, as opposed to the result of negative selection of CD8-expressing Vα14i NKT cells.

T cell Ig domain and mucin domain 1 engagement on invariant NKT cells in the presence of TCR stimulation enhances IL-4 production but inhibits IFN-gamma production

The T cell Ig domain and mucin domain (TIM)1 protein expressed on the surface of Th2 cells regulates the immune response by modulating cytokine production. However, the functional roles of TIM1 have not been examined in NKT cells. Therefore, we investigated the immunologic effects of TIM1 on NKT cells. We found that mouse NK1.1(+)TCR-beta(+), alpha-galactosyl ceramide/CD1d dimer(+) NKT, and NKT hybridoma (DN32.D3) cells constitutively express TIM1 and TIM4 on their surface. Engagement of TIM1 on NKT cells by any of several anti-TIM1 mAbs suppressed the production of IFN-gamma in the presence of TCR stimulation in vitro and in vivo, whereas the effects of such engagement on Th2 cytokine production by the NKT cells varied with the particular anti-TIM1 Ab clone. Moreover, in DN32.D3 TIM4-knockdown NKT hybridoma cells, TIM1 engagement by rTIM1 or TIM4 enhanced IL-4 production while inhibiting IFN-gamma production in the presence of alpha-galactosyl ceramide stimulation. TIM1 engagement increased GATA-3 expression but reduced T-bet expression in NKT cells in the presence of TCR engagement. The adoptive transfer of NKT cells preincubated with anti-TIM1 mAbs into Jalpha18(-/-) mice aggravated bleomycin-induced pulmonary fibrosis by suppressing IFN-gamma production. Taken together, these results suggest that TIM1 costimulation on NKT cells enhances the cellular production of IL-4 while inhibiting the production of IFN-gamma. Thus, as a differential regulator of the immune response, TIM1 on NKT cells may be a useful therapeutic target for immune diseases.

The role of interleukin-1beta and platelet-derived growth factor-AB in antifibrosis mediated by native human interferon alpha

BACKGROUND

Commercial preparations of native human interferon alpha (nHuIFN-alpha) contain several subtypes of interferon-alpha (IFN-alpha) and traces of other cytokines. Recently, we described its antifibrotic potential and showed nHuIFN-alpha to have a greater effect than that of recombinant human IFN-alpha (rHuIFN-alpha). We hypothesized that cooperation between different cytokines in the nHuIFN-alpha preparation is essential for this effect. Considerable concentrations of interleukin-1beta (IL-1beta) and platelet-derived growth factor AB (PDGF-AB) are present in the nHuIFN-alpha preparations.

METHODS

We tested the viability and the expression of procollagen type I messenger RNA (mRNA) in MRC5 fibroblasts treated with interleukin-1 beta (IL-1beta) and/or PDGF-AB, or the corresponding antibodies in combination with rHuIFN-alpha or nHuIFN-alpha.

RESULTS

We showed that neither IL-1beta nor PDGF-AB significantly affect the viability of MRC5 cells. Furthermore, cell viability was not affected when IL-1beta or PDGF-AB were applied along with rHuIFN-alpha, relative to the viability of cells treated with rHuIFN-alpha only. In contrast, both cytokines suppressed the synthesis of procollagen type I mRNA. When coadministered with rHuIFN-alpha, IL-1beta enhanced the suppression induced by rHuIFN-alpha. Conversely, PDGF-AB acted as an antagonist of rHuIFN-alpha and restored partially the synthesis of procollagen type I mRNA. Interestingly, the addition of IL-1beta to the PDGF-AB/rHuIFN-alpha mix not only abolished the antagonistic activity of PDGF-AB but also decreased the synthesis of procollagen type I mRNA beyond the level achieved by IL-1beta/rHuIFN-alpha. Therefore, IL-1beta was able to reverse the activity of PDGF-AB.

CONCLUSION

Our study suggests that IL-1beta is an important component of nHuIFN-alpha preparations, acting directly and indirectly to modulate the action of other components. This study provides insight into these complex cytokine networks, which is necessary for better and safer antifibrotic therapy.

IFN-gamma is a master regulator of endotoxin shock syndrome in mice primed with heat-killed Propionibacterium acnes

Hyper-coagulation, hypothermia, systemic inflammatory responses and shock are major clinical manifestations of endotoxin shock syndrome in human. As previously reported, mice primed with heat-killed Propionibacterium acnes are highly susceptible to the action of LPS to induce tumour necrosis factor (TNF)-alpha and to that of TNF-alpha to trigger lethal shock. Here we investigated the mechanisms underlying the P. acnes-induced sensitization to LPS and TNF-alpha and the development of individual symptoms after subsequent challenge with LPS or TNF-alpha. Propionibacterium acnes-primed wild-type (WT) mice, but not naive mice, exhibited hyper-coagulation with elevated levels of thrombin-antithrombin complexes and anti-fibrinolytic plasminogen activator inhibitor 1 in their plasma, hypothermia, systemic inflammatory responses and high mortality rate after LPS or TNF-alpha challenge. Propionibacterium acnes treatment reportedly induces both T(h)1 and T(h)17 cell development. Propionibacterium acnes-primed Il12p40(-/-) and Ifngamma(-/-) mice, while not Il17A(-/-) mice, evaded all these symptoms/signs upon LPS or TNF-alpha challenge, indicating essential requirement of IL-12-IFN-gamma axis for the sensitization to LPS and TNF-alpha. Furthermore, IFN-gamma blockade just before LPS challenge could prevent P. acnes-primed WT mice from endotoxin shock syndrome. These results demonstrated requirement of IFN-gamma to the development of endotoxin shock and suggested it as a potent therapeutic target for the treatment of septic shock.

Cytokine orchestration in post-operative peritoneal adhesion formation

Peritoneal adhesions are a near inevitable occurrence after laparotomy and a major cause of both patient and physician misery. To date, clinical attempts at their amelioration have concentrated on manipulating the physical factors that affect their development despite a wealth of experimental data elucidating the molecular mechanisms that underlie their initiation, development and maturation. However, the advent of targeted, specific anti-cytokine agents as directed therapy for inflammatory and neoplastic conditions raises the prospect of a new era for anti-adhesion strategies. To harness this potential will require considerable cross-disciplinary collaboration and that surgeon-scientists propel themselves to the forefront of this emerging field.