Suppression of proinflammatory cytokines in monocytes by a tetravalent guanylhydrazone

Hypusination-induced DHPS/eIF5A pathway as a new therapeutic strategy for human diseases: A mechanistic review and structural classification of DHPS inhibitors

The discovery of new therapeutic strategies for diseases is essential for drug research. Deoxyhypusine synthase (DHPS) is a critical enzyme that modifies the conversion of the eukaryotic translation initiation factor 5A (eIF5A) precursor into physiologically active eIF5A (eIF5A-Hyp). Recent studies have revealed that the hypusine modifying of DHPS on eIF5A has an essential regulatory role in human diseases. The hypusination-induced DHPS/eIF5A pathway has been shown to play an essential role in various cancers, and it could regulate immune-related diseases, glucose metabolism-related diseases, neurological-related diseases, and aging. In addition, DHPS has a more defined substrate and a well-defined structure within the active pocket than eIF5A. More and more researchers are focusing on the prospect of advanced development of DHPS inhibitors. This review summarizes the regulatory mechanisms of the hypusination-induced DHPS/eIF5A pathway in a variety of diseases in addition to the inhibitors related to this pathway; it highlights and analyzes the structural features and mechanisms of action of DHPS inhibitors and expands the prospects of future drug development using DHPS as an anticancer target.

Dual red and near-infrared light-emitting diode irradiation ameliorates LPS-induced otitis media in a rat model

Objective: Otitis media (OM) is an infectious and inflammatory disease of the middle ear (ME) that often recurs and requires long-term antibiotic treatment. Light emitting diode (LED)-based devices have shown therapeutic efficacy in reducing inflammation. This study aimed to investigate the anti-inflammatory effects of red and near-infrared (NIR) LED irradiation on lipopolysaccharide (LPS)-induced OM in rats, human middle ear epithelial cells (HMEECs), and murine macrophage cells (RAW 264.7). Methods: An animal model was established by LPS injection (2.0 mg/mL) into the ME of rats via the tympanic membrane. A red/NIR LED system was used to irradiate the rats (655/842 nm, intensity: 102 mW/m², time: 30 min/day for 3 days and cells (653/842 nm, intensity: 49.4 mW/m², time: 3 h) after LPS exposure. Hematoxylin and eosin staining was performed to examine pathomorphological changes in the tympanic cavity of the ME of the rats. Enzyme-linked immunosorbent assay, immunoblotting, and RT-qPCR analyses were used to determine the mRNA and protein expression levels of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α). Mitogen-activated protein kinases (MAPKs) signaling was examined to elucidate the molecular mechanism underlying the reduction of LPS-induced pro-inflammatory cytokines following LED irradiation. Results: The ME mucosal thickness and inflammatory cell deposits were increased by LPS injection, which were reduced by LED irradiation. The protein expression levels of IL-1β, IL-6, and TNF-α were significantly reduced in the LED-irradiated OM group. LED irradiation strongly inhibited the production of LPS-stimulated IL-1β, IL-6, and TNF-α in HMEECs and RAW 264.7 cells without cytotoxicity in vitro. Furthermore, the phosphorylation of ERK, p38, and JNK was inhibited by LED irradiation. Conclusion: This study demonstrated that red/NIR LED irradiation effectively suppressed inflammation caused by OM. Moreover, red/NIR LED irradiation reduced pro-inflammatory cytokine production in HMEECs and RAW 264.7 cells through the blockade of MAPK signaling.

CNS-Spleen Axis - a Close Interplay in Mediating Inflammatory Responses in Burn Patients and a Key to Novel Burn Therapeutics

Severe burn-induced inflammation and subsequent hypermetabolic response can lead to profound infection and sepsis, resulting in multiple organ failure and high mortality risk in patients. This represents an extremely challenging issue for clinicians as sepsis is the leading cause of mortality in burn patients. Since hyperinflammation and immune dysfunction are a result of an immune imbalance, restoring these conditions seem to have promising benefits for burn patients. A key network that modulates the immune balance is the central nervous system (CNS)-spleen axis, which coordinates multiple signaling pathways, including sympathetic and parasympathetic pathways. Modulating inflammation is a key strategy that researchers use to understand neuroimmunomodulation in other hyperinflammatory disease models and modulating the CNS-spleen axis has led to improved clinical outcomes in patients. As the immune balance is paramount for recovery in burn-induced sepsis and patients with hyperinflammatory conditions, it appears that severe burn injuries substantially alter this CNS-spleen axis. Therefore, it is essential to address and discuss the potential therapeutic techniques that target the CNS-spleen axis that aim to restore homeostasis in burn patients. To understand this in detail, we have conducted a systematic review to explore the role of the CNS-spleen axis and its impact on immunomodulation concerning the burn-induced hypermetabolic response and associated sepsis complications. Furthermore, this thorough review explores the role of the spleen, CNS-spleen axis in the ebb and flow phases following a severe burn, how this axis induces metabolic factors and immune dysfunction, and therapeutic techniques and chemical interventions that restore the immune balance via neuroimmunomodulation.

Biodegradable amino acid-based poly(ester amine) with tunable immunomodulating properties and their in vitro and in vivo wound healing studies in diabetic rats' wounds

The objective of this study is to design a new family of biodegradable synthetic polymeric biomaterials for providing a tunable inhibition of macrophage's nitric oxide synthase (NOS) pathway. l-Arginine (Arg) is the common substrate for NOS and arginase. Both two metabolic pathways participate in the wound healing process. An impaired wound healing, such as diabetic or other chronic wounds is usually associated with an overproduction of NO by macrophages via the NOS pathway. In this study, a new family of l-nitroarginine (NOArg) based polyester amide (NOArg-PEA) and NOArg-Arg PEA copolymers (co-PEA) were designed and synthesized with different composition ratios. The NOArg-PEA and NOArg-Arg co-PEAs are biodegradable (more than 50% degradation in vitro in 4 days at 37 °C), biocompatible and did not activate the resting macrophage immune response per se. When classically activated or alternatively activated macrophages (CAM/AAM) were incubated with NOArg-PEA and NOArg-Arg co-PEAs, the treatments decreased the NO production of CAM, increased the arginase activity in both CAM and AAM, increased TGF-β1 production of CAM to various degrees and had no significant effect on TNF-α production. Diabetic rat models were used to evaluate the efficacy of NOArg-PEA and NOArg-Arg co-PEAs on wound healing. Diabetic rats treated with 2-NOArg-4 PEA, 2-NOArg-4-Arg-4 20/80, and 2-NOArg-4-Arg-4 50/50 biomaterials achieved 40%-80% faster-wound healing when compared with the control on day 7. The data from the histological and immunohistochemical analysis showed that the 2-NOArg-4-Arg-4 20/80 and 2-NOArg-4-Arg-4 50/50 treatments led to more AAM phenotypes (CD206) and arginase I production in wound tissue than the control during the first 7 days, i.e., suggesting pro-healing wound microenvironment with improved re-epithelialization of wound healing. A similar trend was retained until day 14. The 2-NOArg-4-Arg-4 20/80 and 2-NOArg-4-Arg-4 50/50 treatments also increased the collagen deposition and angiogenesis in the healing wound between day 7 and day 14. Both in vitro and in vivo data of this study showed that this new family of NOArg-Arg co-PEA biomaterials have the potential as viable alternatives for treating impaired wound healing, such as diabetic or other types of chronic wounds. STATEMENT OF SIGNIFICANCE: Diabetic or other chronic wounds is usually associated with an overproduction of NO and pro-inflammatory signals by macrophages. Arginine supplement or NOS inhibitors administration failed to achieve an expected improved wound healing because of the dynamic complexity of arginine catabolism, the difficulty in transition from pro-inflammatory to pro-healing, and the short-term efficacy. We designed and synthesized a new family of water-soluble and degradable nitroarginine-arginine polyester amides to rebalance NOS/arginase metabolism pathways of macrophages. They showed tunable immunomodulating properties in vitro. The in vivo studies were performed to evaluate their efficacy in accelerating the healing. These new biomaterials have the potential as viable alternatives for treating impaired wound healing. The general audience of Acta Biomaterialia should be interested in these findings.

Neuro-immune interactions in inflammation and host defense: Implications for transplantation

Sensory and autonomic neurons of the peripheral nervous system (PNS) play a critical role in regulating the immune system during tissue inflammation and host defense. Recent studies have identified the molecular mechanisms underlying the bidirectional communication between the nervous system and the immune system. Here, we highlight the studies that demonstrate the importance of the neuro-immune interactions in health and disease. Nociceptor sensory neurons detect immune mediators to produce pain, and release neuropeptides that act on the immune system to regulate inflammation. In parallel, neural reflex circuits including the vagus nerve-based inflammatory reflex are physiological regulators of inflammatory responses and cytokine production. In transplantation, neuro-immune communication could significantly impact the processes of host-pathogen defense, organ rejection, and wound healing. Emerging approaches to target the PNS such as bioelectronics could be useful in improving the outcome of transplantation. Therefore, understanding how the nervous system shapes the immune response could have important therapeutic ramifications for transplantation medicine.

The multi-target effects of CNI-1493: convergence of anti-amylodogenic and anti-inflammatory properties in animal models of Alzheimer's disease

After several decades of Alzheimer's disease (AD) research and failed clinical trials, one can speculate that targeting a single pathway is not sufficient. However, a cocktail of novel therapeutics will constitute a challenging clinical trial. A more plausible approach will capitalize on a drug that has relevant and synergistic multiple-target effects in AD. We have previously demonstrated the efficacy of CNI-1493 in the CRND8 transgenic AD mouse model. Similar to many anti-inflammatory drugs that were tested in preclinical model of AD, it was speculated that the significant effect of CNI-1493 is due to its established anti-inflammatory properties in rodents and humans. In the present study, we set out to elucidate the protective mechanism of CNI-1493 as a drug simultaneously targeting several aspects of AD pathology. Using C1213, a highly similar analogue of CNI-1493 that lacks anti-inflammatory properties, we show that both compounds directly interact with soluble and insoluble Amyloid β (Aβ) aggregates and attenuate Aβ cytotoxicity in vitro. Additionally, CNI-1493 and C1213 ameliorated Aβ-induced behavioral deficits in nematodes. Finally, C1213 reduced Aβ plaque burden and cognitive deficits in transgenic CRND8 mice to a similar extent as previously shown with CNI-1493. Taken together, our findings suggest anti-amyloidogenic activity as a relevant component for the in-vivo efficacy of CNI-1493 and its analogue C1213. Thus, CNI-1493, a drug with proven safety in humans, is a viable candidate for novel multi-target therapeutic approaches to AD.

Protection against lethal polymicrobial sepsis by CNI-1493, an inhibitor of pro-inflammatory cytokine synthesis

Polymicrobial sepsis caused by cecal ligation and puncture (CLP) in mice produces the inflammatory and pathological sequelae of lung neutrophil infiltration, adult respiratory distress syndrome (ARDS) and death. These sequelae are dependent upon the synergistic interaction between several inflammatory mediators, including tumor necrosis factor (TNF), interleukin 1 (IL-1 ), and nitric oxide (NO). The overlapping spectrum of multiple mediator toxicity has hampered efforts to develop therapies for sepsis based on selective inhibition of a single mediator. Therefore, we tested the hypothesis that inhibition of multiple pro-inflammatory mediators would abrogate lethality. Our results show that administration of a tetravalent guanylhydrazone compound (CNI-1493) protected mice against 10 day mortality in CLP. Evidence of suppression of the cytokine cascade was given by decreased serum levels of TNF and IL-6 in CNI-1493 treated animals (TNF reduced 60% as compared to controls; IL-6 reduced 90% compared to controls; P < 0.05), and decreased levels of the acute-phase protein serum amyloid A response measured 24 h after CLP. Serum nitrites/nitrates, which give an index of NO production, were also significantly reduced (50%). Protection against CLP induced lung damage was observed as attenuation of edema and alveolar neutrophil infiltration, suppression of pulmonary TNF levels, and reduction of TUNEL-positive staining in lung. We conclude that CNI-1493 effectively inhibits the synthesis of multiple pro-inflammatory mediators and protects against death during polymicrobial sepsis.

Neural inhibition of inflammation: the cholinergic anti-inflammatory pathway

The innate immune system is activated by infection and injury to release pro-inflammatory cytokines, which activate macrophages and neutrophils and modulate specific cellular responses. The magnitude of the cytokine response is critical, because a deficient response may result in secondary infections, while an excessive response may be more injurious than the original insult. We recently described a neural pathway, termed the `cholinergic anti-inflammatory pathway', that reflexively monitors and adjusts the inflammatory response by inhibiting pro-inflammatory cytokine synthesis. Efferent signals in the vagus nerve provide a direct mechanism for neural regulation of the immune response that is rapid, localized, and integrated. Vagus nerve stimulation inhibits the release of TNF, HMGB1, and other cytokines, and protects against endotoxemia and ischemia-reperfusion injury. This newly identified physiological mechanism of maintaining immunological homeostasis suggests that novel therapeutics may effectively modulate inflammatory responses by activating the cholinergic anti-inflammatory pathway.

Experimental Anti-Inflammatory Drug Semapimod Inhibits TLR Signaling by Targeting the TLR Chaperone gp96

Semapimod, a tetravalent guanylhydrazone, suppresses inflammatory cytokine production and has potential in a variety of inflammatory and autoimmune disorders. The mechanism of action of Semapimod is not well understood. In this study, we demonstrate that in rat IEC-6 intestinal epithelioid cells, Semapimod inhibits activation of p38 MAPK and NF-κB and induction of cyclooxygenase-2 by TLR ligands, but not by IL-1β or stresses. Semapimod inhibits TLR4 signaling (IC50 ≈0.3 μmol) and acts by desensitizing cells to LPS; it fails to block responses to LPS concentrations of ≥5 μg/ml. Inhibition of TLR signaling by Semapimod is almost instantaneous: the drug is effective when applied simultaneously with LPS. Semapimod blocks cell-surface recruitment of the MyD88 adapter, one of the earliest events in TLR signaling. gp96, the endoplasmic reticulum-localized chaperone of the HSP90 family critically involved in the biogenesis of TLRs, was identified as a target of Semapimod using ATP-desthiobiotin pulldown and mass spectroscopy. Semapimod inhibits ATP-binding and ATPase activities of gp96 in vitro (IC50 ≈0.2-0.4 μmol). On prolonged exposure, Semapimod causes accumulation of TLR4 and TLR9 in perinuclear space, consistent with endoplasmic reticulum retention, an anticipated consequence of impaired gp96 chaperone function. Our data indicate that Semapimod desensitizes TLR signaling via its effect on the TLR chaperone gp96. Fast inhibition by Semapimod is consistent with gp96 participating in high-affinity sensing of TLR ligands in addition to its role as a TLR chaperone.

The Macrophage Inhibitor CNI-1493 Blocks Metastasis in a Mouse Model of Ewing Sarcoma through Inhibition of Extravasation

Metastatic Ewing Sarcoma carries a poor prognosis, and novel therapeutics to prevent and treat metastatic disease are greatly needed. Recent evidence demonstrates that tumor-associated macrophages in Ewing Sarcoma are associated with more advanced disease. While some macrophage phenotypes (M1) exhibit anti-tumor activity, distinct phenotypes (M2) may contribute to malignant progression and metastasis. In this study, we show that M2 macrophages promote Ewing Sarcoma invasion and extravasation, pointing to a potential target of anti-metastatic therapy. CNI-1493 is a selective inhibitor of macrophage function and has shown to be safe in clinical trials as an anti-inflammatory agent. In a xenograft mouse model of metastatic Ewing Sarcoma, CNI-1493 treatment dramatically reduces metastatic tumor burden. Furthermore, metastases in treated animals have a less invasive morphology. We show in vitro that CNI-1493 decreases M2-stimulated Ewing Sarcoma tumor cell invasion and extravasation, offering a functional mechanism through which CNI-1493 attenuates metastasis. These data indicate that CNI-1493 may be a safe and effective adjuvant agent for the prevention and treatment of metastatic Ewing Sarcoma.

Semapimod sensitizes glioblastoma tumors to ionizing radiation by targeting microglia

Glioblastoma is the most malignant and lethal form of astrocytoma, with patients having a median survival time of approximately 15 months with current therapeutic modalities. It is therefore important to identify novel therapeutics. There is mounting evidence that microglia (specialized brain-resident macrophages) play a significant role in the development and progression of glioblastoma tumors. In this paper we show that microglia, in addition to stimulating glioblastoma cell invasion, also promote glioblastoma cell proliferation and resistance to ionizing radiation in vitro. We found that semapimod, a drug that selectively interferes with the function of macrophages and microglia, potently inhibits microglia-stimulated GL261 invasion, without affecting serum-stimulated glioblastoma cell invasion. Semapimod also inhibits microglia-stimulated resistance of glioblastoma cells to radiation, but has no significant effect on microglia-stimulated glioblastoma cell proliferation. We also found that intracranially administered semapimod strongly increases the survival of GL261 tumor-bearing animals in combination with radiation, but has no significant benefit in the absence of radiation. In conclusion, our observations indicate that semapimod sensitizes glioblastoma tumors to ionizing radiation by targeting microglia and/or infiltrating macrophages.

The novel guanylhydrazone CPSI-2364 ameliorates ischemia reperfusion injury after experimental small bowel transplantation

BACKGROUND

Resident macrophages within the tunica muscularis are known to play a crucial role in initiating severe inflammation in response to ischemia reperfusion injury after intestinal transplantation contributing to graft dysmotility, bacterial translocation, and possibly, acute rejection. The p38 mitogen-activated protein kinase is a key player in the signaling of proinflammatory cytokine synthesis in macrophages. Therefore, we investigated the effects of CPSI-2364, an apparent macrophage-specific inhibitor of the p38 mitogen-activated protein kinase pathway in an isogenic intestinal rat transplantation model.

METHODS

Recipient and donor animals were treated perioperatively with CPSI-2364 (1 mg/kg, intravenously) or vehicle solution. Nontransplanted animals served as control. Animals were killed 30 min, 3 hr, and 18 hr after reperfusion.

RESULTS

CPSI-2364 treatment resulted in significantly less leukocyte infiltration and significantly improved graft motor function (18 hr). Messenger RNA expression of proinflammatory cytokines (interleukin 6) and kinetic active mediators (NO) was reduced by CPSI-2364 in the early phase after transplantation. Histologic evaluation revealed the protective effects of CPSI-2364 treatment by a significantly less destruction of mucosal integrity at all time points. Perioperative treatment with CPSI-2364 improves graft motor function through impaired inflammatory responses to ischemia reperfusion injury by inhibition of proinflammatory cytokines and suppression of nitric oxide production in macrophages.

CONCLUSIONS

CPSI-2364 presents as a promising complementary pharmacological approach preventing postoperative dysmotility for clinical intestinal transplantation.

CNI-1493 attenuates neuroinflammation and dopaminergic neurodegeneration in the acute MPTP mouse model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is associated with neurodegeneration of dopaminergic neurons in the substantia nigra. Neuroinflammatory processes have been shown to be a key component of this neurodegeneration and, as such, small molecule compounds which inhibit these inflammatory events are a critical research focus.

OBJECTIVE

CNI-1493 is an anti-inflammatory compound that strongly inhibits macrophages and also stimulates the cholinergic anti-inflammatory pathway. We have examined whether CNI-1493 has a neuroprotective effect in the acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD.

METHODS

CNI-1493 (8 mg/kg i.p.) or placebo administration was started 1 day before MPTP intoxication and repeated daily until sacrifice after MPTP intoxication. C57/Bl6 mice - either treated with CNI-1493 or with placebo - were injected intraperitoneally 4 times at 2-hour intervals with either 20 mg/kg MPTP-HCl or a corresponding volume of saline. Two or 7 days after the end of the MPTP intoxication, the animals were killed and their brains were processed for further analysis.

RESULTS

Administration of CNI-1493 markedly protected tyrosine hydroxylase-positive substantia nigra neurons against MPTP neurotoxicity. CNI-1493 treatment in the MPTP model was also accompanied by a profound reduction of activated microglia within the substantia nigra, as measured by ionized calcium-binding adapter molecule-1 staining.

CONCLUSIONS

These findings support that CNI-1493 could reduce the MPTP-induced toxicity likely by inhibition of neuroinflammatory responses. The neuroprotective effect of CNI-1493 suggests that CNI-1493 might be a valuable neuroprotective candidate in the future treatment of PD.

Neural reflexes in inflammation and immunity

The mammalian immune system and the nervous system coevolved under the influence of infection and sterile injury. Knowledge of homeostatic mechanisms by which the nervous system controls organ function was originally applied to the cardiovascular, gastrointestinal, musculoskeletal, and other body systems. Development of advanced neurophysiological and immunological techniques recently enabled the study of reflex neural circuits that maintain immunological homeostasis, and are essential for health in mammals. Such reflexes are evolutionarily ancient, dating back to invertebrate nematode worms that possess primitive immune and nervous systems. Failure of these reflex mechanisms in mammals contributes to nonresolving inflammation and disease. It is also possible to target these neural pathways using electrical nerve stimulators and pharmacological agents to hasten the resolution of inflammation and provide therapeutic benefit.

Microencapsulated drug delivery: a new approach to pro-inflammatory cytokine inhibition

CONTEXT

This article reviews the use of albumin microcapsules 3-4 µm in size containing cytokine inhibiting drugs which include neutralizing antibodies to TNF and IL1, CNI-1493, antisense oligonucleotides to TNF and NF-kappaB, and the antioxidant catalase.

OBJECTIVE

Describe the effects, cellular uptake and distribution of microencapsulated drugs and the effect in both a peritonitis model of infection and a model of adjuvant-induced arthritis.

METHODS

The studies performed by our group are reviewed, the only such studies available.

RESULTS

Microencapsulation of these compounds produced high intracellular drug concentrations due to rapid uptake by phagocytic cells, including endothelial cells, without toxicity. All compounds produced excellent inhibition of TNF and IL1 resulting in improved animal survival in a peritonitis model of septic shock and inflammation in an arthritis model.

CONCLUSION

Albumin microencapsulated pro-inflammatory cytokine inhibiting compounds are superior to equivalent concentration of these compounds administered in solution form.

Synergism in survival to endotoxic shock in rats given microencapsulated CNI-1493 and antisense oligomers to NF-kappaB

The synthesis of TNF may be inhibited at the transcriptional level by antisense to either TNF or NF-kappaB or at the post-transcriptional level by CNI-1493, a guanylhydrazone compound which inhibits p38 MAP kinase activity. Previous studies have demonstrated that targeting macrophages and other phagocytic cells by intracellular drug delivery using albumin microcapsules containing either antisense oligomers to NF-kappaB or CNI-1493 greatly enhances intracellular drug concentration and survival in both endotoxic shock and sepsis models. It is the purpose of this study to determine if microencapsulated drugs acting at different stages in the synthesis of TNF are synergistic. Four groups of 10 rats each were given 15 mg kg(-1) of E.coli endotoxin and treated with (1) CNI-1493 1 mg kg(-1), (2) antisense oligomers to NF-kappaB at 100 mcg, (3) CNI-1493 1 mg kg(-1) plus antisense kappa to NF- at 100 mg kg(-1) and (4) CNI-1493 200 mg kg(-1) plus antisense oligomer to NF-kappaB at 200 mg kg(-1). TNF and IL1 were measured by ELISA at 4, 8, 24 and 48 h. The rats were observed for 5 days. The combination of CNI-1493 and antisense oligomers to NF-kappaB inhibited TNF 41% greater that CNI alone and 51% greater than antisense oligomers to NF-kappaB alone at 4 h after endotoxin administration. Survival at 5 days with CNI alone was 0%, 20% with antisense oligomers to NF-kappaB and 60% with the combination. In conclusion, synergism in survival occurs using microencapsulated drugs acting at different points in the synthesis of TNF was demonstrated using an in-vivo model of endotoxic shock. Both the amount of TNF inhibition and the mortality were significantly improved with combination therapy. Multiple drugs acting at different sites in the synthesis of TNF may be useful in the treatment of disease states characterized by pro-inflammatory cytokine release.

Patented small molecules against psoriasis

BACKGROUND

It is hypothesized that psoriasis is an autoimmune disease. The most recent therapeutic approach that proved to be more effective than earlier methods of treatment is the use of mAb/fusion proteins. Efforts nowadays are focused on investigating the antipsoriatic affect of small molecules that can be administered orally, some of which are capable of entering cells, and being selective in targeting intracellular pathways.

OBJECTIVE

Preclinical patented small molecules that are recommended for the treatment of psoriasis are reviewed. Emphasis is placed on their mechanism of action.

METHODS

http://ep.espacenet.com/ , Pubmed, Scopus and Google websites were the main sources used for the patented small molecule search. A number of patents were poorly described and difficulties were faced in trying to figure out the patentee(s) explanation. Moreover, most patents were recommended for the treatment of a number of autoimmune diseases and cancer, and not only for psoriasis.

RESULTS/CONCLUSIONS

Small molecules that inhibit the activation of T lymphocytes, leukocyte trafficking, leukotriene activity/production and angiogenesis, and promote apoptosis have been patented. Small molecules that have been patented for the treatment of other autoimmune diseases and could be used for treating psoriasis are described. Moreover, other possible mechanistic approaches using small molecules are discussed.

Proinflammatory cytokines in CRP baseline regulation

Low-grade inflammation, a minor elevation in the baseline concentration of inflammatory markers such as C-reactive protein (CRP), is nowadays recognized as an important underlying condition in many common diseases. Concentrations of CRP under 10 mg/1 are called low-grade inflammation and values above that are considered as clinically significant inflammatory states. Epidemiological studies have revealed demographic and socioeconomic factors that associate with CRP concentration; these include age, sex, birth weight, ethnicity, socioeconomic status, body mass index (BMI), fiber consumption, alcohol intake, and dietary fatty acids. At the molecular level, production of CRP is induced by proinflammatory cytokines IL-1, IL-6, and IL-17 in the liver, although extra hepatic production most likely contributes to systemic concentrations. The cytokines are produced in response to, for example, steroid hormones, thrombin, C5a, bradykinin, other cytokines, UV-light, neuropeptides and bacterial components, such as lipopolysaccharide. Cytokines exert their biological effects on CRP by signaling through their receptors on hepatic cells and activating different kinases and phosphatases leading to translocation of various transcription factors on CRP gene promoter and production of CRP protein. Genetic polymorphisms in the interleukin genes as well as in CRP gene have been associated with minor elevation in CRP. As minor elevation in CRP is associated with both inflammatory and noninflammatory conditions, it should be noticed that the elevation might just reflect distressed or injured cells homeostasis maintenance in everyday life, rather than inflammation with classical symptoms of redness, swelling, heat, and pain.

Local and systemic chemokine patterns in a human musculoskeletal trauma model

OBJECTIVE AND DESIGN

This prospective study aims to identify differences in local and systemic chemokines kinetics within 24 h of a standardised human surgical trauma (total hip arthroplasty) and their impact on systemic polymorphonuclear cells.

MATERIALS AND METHODS

We examined seven patients with coxarthrosis, but without comorbidity, who had a total hip arthroplasty. Local drained blood and systemic blood samples were collected at wound closure and at 1, 4, and 24 h after surgery. Chemokines were measured using a multiplex antibody bead kit. Venous whole blood cell counts were taken at the same points in time.

RESULTS

There is a significant postoperative local burst of CCL2 and CXCL8 while systemic levels stay unchanged. The systemic levels of CCL3, CCL4, CCL5, CCL11, CXCL9, and CXCL10 were significantly reduced at 24 h post-surgery, but local levels remain unchanged or had only modest changes. There was a significant postoperative rise in monocytes and neutrophils.

CONCLUSION

There is fundamental difference between local and systemic chemokine kinetics in the human trauma model studied. High postoperative concentrations of CCL2 and CXCL8 at the site of inflammation form a gradient that contributes to the recruitment of neutrophils and monocytes at the trauma site.

Inhibition of p38 mitogen-activated protein kinase pathway as prophylaxis of postoperative ileus in mice

BACKGROUND & AIMS

Postoperative ileus, an iatrogenic complication of abdominal surgery, is mediated by severe inflammation of the tunica muscularis. Macrophages that reside in the muscularis have important roles in initiating the inflammation. We investigated whether activation of the p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase is involved in the genesis of postoperative ileus, and whether p38-MAPK inhibition by the macrophage-specific inhibitor semapimod prevents intestinal dysmotility.

METHODS

Postoperative ileus was induced by intestinal manipulation of the small bowel in mice. Protein kinase phosphorylation was assessed by immunoblotting of muscularis externa preparations. Proinflammatory gene expression was quantified by real-time polymerase chain reaction. Myeloperoxidase histochemistry for neutrophils was performed in jejunal segments. Nitric oxide production was measured by Griess reaction in smooth-muscle organ culture supernatants. Jejunal contractility was assessed within an organ bath setup. Intestinal motility was analyzed by gastrointestinal and colonic transit measurements.

RESULTS

High levels of p38-MAPK and stress-activated protein kinase phosphorylation were observed immediately after intestinal manipulation. Semapimod treatment led to a significant decrease of p38-MAPK phosphorylation in macrophages; proinflammatory gene expression of macrophage inflammatory protein-1alpha, interleukin-6, monocyte chemoattractant protein-1, and intercellular adhesion molecule-1; and neutrophil infiltration. Furthermore, semapimod completely abrogated nitric oxide production within the tunica muscularis. Subsequently, semapimod prevented the suppression of smooth muscle contractility and small intestinal and colonic motility after intestinal manipulation.

CONCLUSION

A single preoperative semapimod administration prevents intestinal macrophage activation and subsequent gastrointestinal dysmotility induced by abdominal surgery. Semapimod inhibits p38-MAPK and nitric oxide production in macrophages, making it a promising strategy for prophylaxis of postoperative ileus.

Blockade of endogenous proinflammatory cytokines ameliorates endothelial dysfunction in obese Zucker rats

To study the role of endogenous proinflammatory cytokines in endothelial dysfunction in diabetes, we administered semapimod, an inhibitor of proinflammatory cytokine production, to obese Zucker (OZ) rats, and examined its effect on endothelium-dependent vasorelaxation. Endothelium-dependent vasorelaxation induced by acetylcholine and adrenomedullin (AM) was significantly reduced in OZ rats compared to a control group of lean Zucker rats. Semapimod significantly restored endothelium-dependent vasorelaxation in OZ rats. This effect of semapimod was well correlated with the reduction in the serum concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-6, and C-reactive protein, as well as with the recovery of AM-induced Akt phosphorylation and cGMP production. Furthermore, acute administration of TNF-alpha significantly suppressed endothelium-dependent vasorelaxation and AM-induced cGMP production. These results implicate endogenous proinflammatory cytokines, especially TNF-alpha, in endothelial dysfunction in diabetes, and indicate that blockade of these cytokines will be a promising strategy for inhibiting the progression of vascular inflammation.

CNI-1493 inhibits Abeta production, plaque formation, and cognitive deterioration in an animal model of Alzheimer's disease

Alzheimer's disease (AD) is characterized by neuronal atrophy caused by soluble amyloid β protein (Aβ) peptide “oligomers” and a microglial-mediated inflammatory response elicited by extensive amyloid deposition in the brain. We show that CNI-1493, a tetravalent guanylhydrazone with established antiinflammatory properties, interferes with Aβ assembly and protects neuronal cells from the toxic effect of soluble Aβ oligomers. Administration of CNI-1493 to TgCRND8 mice overexpressing human amyloid precursor protein (APP) for a treatment period of 8 wk significantly reduced Aβ deposition. CNI-1493 treatment resulted in 70% reduction of amyloid plaque area in the cortex and 87% reduction in the hippocampus of these animals. Administration of CNI-1493 significantly improved memory performance in a cognition task compared with vehicle-treated mice. In vitro analysis of CNI-1493 on APP processing in an APP-overexpressing cell line revealed a significant dose-dependent decrease of total Aβ accumulation. This study indicates that the antiinflammatory agent CNI-1493 can ameliorate the pathophysiology and cognitive defects in a murine model of AD.

The guanylhydrazone CNI-1493: an inhibitor with dual activity against malaria-inhibition of host cell pro-inflammatory cytokine release and parasitic deoxyhypusine synthase

Malaria is still a major cause of death in the tropics. There is an urgent need for new anti-malarial drugs because drug-resistant plasmodia frequently occur. Over recent years, we elucidated the biosynthesis of hypusine, a novel amino acid contained in eukaryotic initiation factor 5A (eIF-5A) in Plasmodium. Hypusine biosynthesis involves catalysis of deoxyhypusine synthase (DHS) in the first step of post-translational modification. In a screen for new inhibitors of purified plasmodium DHS, CNI-1493, a novel selective pro-inflammatory cytokine inhibitor used in clinical phase II for the treatment of Crohn's disease, inhibited the enzyme of the parasite 3-fold at a concentration of 2 microM. In vitro experiments with 200 microM CNI-1493 in Plasmodium-infected erythrocytes, which lack nuclei and DHS protein, showed a parasite clearance within 2 days. This can presumably be attributed to an anti-proliferating effect because of the inhibition of DHS by the parasite. The determined IC50 of CNI-1493 was 135.79 microM after 72 h. In vivo application of this substance in Plasmodium berghei ANKA-infected C57BL/6 mice significantly reduced parasitemia after dosage of 1 mg/kg or 4 mg/kg/body weight and prevented death of mice with cerebral malaria. This effect was paralleled by a decrease in serum TNF levels of the mice. We suggest that the new mechanism of CNI-1493 is caused by a decrease in modified eIF-5A biosynthesis with a downstream effect on the TNF synthesis of the host. From the current data, we consider CNI-1493 to be a promising drug for anti-malarial therapy because of its combined action, i.e., the decrease in eIF-5A biosynthesis of the parasite and host cell TNF biosynthesis.

A novel inhibitor of inflammatory cytokine production (CNI-1493) reduces rodent post-hemorrhagic vasospasm

INTRODUCTION

Cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) is a devastating complication, yet despite multiple lines of investigation an effective treatment remains lacking. Cytokine-mediated inflammation has been implicated as a causative factor in the development of posthemorrhagic vasospasm. In previous experiments using the rat femoral artery model of vasospasm, we demonstrated that elevated levels of the proinflammatory cytokine interleukin (IL)-6 are present after hemorrhage and that a polyclonal antibody against IL-6 is capable of attenuating experimental vasospasm.

METHODS

In the present study, we tested the ability of a novel selective proinflammatory cytokine inhibitor (CNI-1493) to protect against the occurrence of experimental vasospasm in the same rat femoral artery model. CNI-1493 was administered by injection directly into the blood-filled femoral pouches of animals at the time of their initial surgery (hemorrhage). Control animals received an equal volume of vehicle alone. Animals were killed at 8 days posthemorrhage and degree of vasospasm was assessed by image analysis of artery cross-sectional area. In a separate series of experiments, enzyme-linked immunosorbent assay (ELISA) was used to assess levels of the proinflammatory cytokine IL-6 and the prototypical antiinflammatory cytokine transforming growth factor (TGF)-beta1 after treatment with CNI-1493.

RESULTS

Pretreatment with CNI-1493 provided dose-dependent attenuation of posthemorrhagic vasospasm, with the highest dose (200 microg in 8 microL dH2O) causing complete reversal of vasospasm (vessel cross-sectional area ratio 1.06 +/- 0.04 versus 0.87 +/- 0.06, p < 0.05, one-way analysis of variance). Assessment of cytokine levels by ELISA confirmed the selectivity of CNI-1493 by demonstrating significant reductions in IL-6 levels, but no suppression of TGF-beta1 levels.

CONCLUSIONS

These findings support the conclusion that inflammatory cytokines, in particular IL-6, play an important role in development of vasospasm in the rat femoral artery model. Furthermore, these results suggest that the inhibition of inflammatory cytokines may be an appropriate strategy for the treatment of vasospasm after SAH.

The role of the intestinal barrier in the pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in neonates and is increasing in frequency because of recent advances in neonatal care. NEC develops in a stressed preterm infant in the setting of intestinal barrier disruption, systemic inflammation, and leads to, multisystem organ failure. The intestinal barrier lies at the interface between microbes within the intestinal lumen and the immune system of the host, and has both immunological and mechanical components. These components serve to protect the host from invading pathogens and, at the same time, provide a surface area for nutrient absorption. Factors that lead to impairments in the function of the intestinal barrier may predispose the host to the invasion of gut-derived microbes and to the development of systemic inflammatory disease. This process, termed "bacterial translocation," may be compounded during instances in which the mechanisms that regulate the repair of the intestinal barrier are disrupted. Bacterial translocation is of particular concern to the newborn patient, in which immaturity of the mechanical barrier and incomplete development of the host immune system combine to render the host at particular risk for the development of intestinal inflammation. This review will serve to provide an overview of recent evidence regarding the components of the intestinal barrier, and the mechanisms by which disruptions in barrier function may contribute to the pathogenesis of NEC.

Tumor necrosis factor as a pharmacological target

As indicated by its name, tumor necrosis factor (TNF), cloned in 1985, was originally described as a macrophage-derived endogenous mediator that can induce hemorrhagic necrosis of solid tumors and kill some tumor cell lines in vitro. Unfortunately, its promising use as an anticancer agent was biased by its toxicity, which was clear soon from the first clinical trials with TNF in cancer. Almost at the same time TNF was being developed as an anticancer drug, it became clear that TNF was identical to a mediator responsible for cachexia associated with sepsis, which was termed cachectin. This research led to the finding that TNF is, in fact, the main lethal mediator of sepsis and to the publication of a huge number of articles showing that TNF inhibits the toxic effects of bacterial endotoxins, which are now described as systemic inflammatory response. Although the clinical trials with anti-TNF in sepsis have not been successful thus far, undoubtedly as a result of the complexity of this clinical setting, these studies ultimately led to the identification of TNF as a key inflammatory mediator and to the development of anti-TNF molecules (soluble receptors and antibodies) for important diseases including rheumatoid arthritis and Crohn’s disease. On the other side, the mechanisms by which TNF and related molecules induce cell death have been studied in depth, and their knowledge might, in the future, suggest means of improve the therapeutic index of TNF in cancer.

Pathophysiology of pulmonary complications of acute pancreatitis

Acute pancreatitis in its severe form is complicated by multiple organ system dysfunction, most importantly by pulmonary complications which include hypoxia, acute respiratory distress syndrome, atelectasis, and pleural effusion. The pathogenesis of some of the above complications is attributed to the production of noxious cytokines. Clinically significant is the early onset of pleural effusion, which heralds a poor outcome of acute pancreatitis. The role of circulating trypsin, phospholipase A2, platelet activating factor, release of free fatty acids, chemoattractants such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, IL-8, fMet-leu-phe (a bacterial wall product), nitric oxide, substance P, and macrophage inhibitor factor is currently studied. The hope is that future management of acute pancreatitis with a better understanding of the pathogenesis of lung injury will be directed against the production of noxious cytokines.

Drug insight: novel small molecules and drugs for immunosuppression

Gastrointestinal diseases can result from the inadequate or excessive response of the immune system to self or innocuous antigens. Moreover, the physiologic activation of the immune system against non-self antigens is a major clinical problem in liver organ transplantation. At present, many drugs are available that suppress the activation of the immune system, although most of the currently used immunosuppressive drugs lack specificity in terms of their molecular targets and, therefore, have the potential to generate numerous side effects. The advances that have been made in understanding the molecular events that underlie the activation of the immune system have led to the development of a new generation of 'small molecules' that are endowed with immunosuppressive properties and can serve as immunomodulatory agents. Among these new small molecules, inhibitors of Janus kinase 3, p21-Rac1 and p38 mitogen-activated protein kinase represent the most innovative approach to immunosuppression, and could be a promising alternative to current immunosuppressive therapies. Here, we report on the progress that has been made in the development of small molecules in the field of gastroenterology.

Recombinant HMGB1 with cytokine-stimulating activity

We describe methods for the isolation, purification, and characterization of full-length high-mobility group box 1 (HMGB1) and truncated mutants expressed in bacteria and in mammalian Chinese Hamster Ovary (CHO) cells. HMGB1 is an abundant nuclear and cytoplasmic protein, highly conserved across species and widely distributed in eukaryotic cells from yeast to man. As a ubiquitous nuclear DNA binding protein, HMGB1 binds DNA, facilitates gene transcription, and stabilizes nucleosome structure. In addition to these intracellular roles, HMGB1 can be released into the extracellular milieu by activated innate immune cells (i.e., macrophages, monocytes) and functions as a mediator of lethal endotoxemia and sepsis. The proinflammatory cytokine activity of HMGB1 has become an intense area of research and recombinant protein can be a useful tool to probe HMGB1 functions. Due to its dipolar charged properties, HMGB1 isolated by some methods can be contaminated with bacterial products (such as CpG DNA or lipopolysaccharide [LPS]) that may interfere with immunological analyses. Here we report our newly developed methods for the isolation and purification of biologically active HMGB1 from bacteria or mammalian CHO cells that is essentially free of contaminants. This strategy provides an important advance in methodology to facilitate future HMGB1 studies.

Effects of CNI-1493 on human granulocyte functions

During acute bacterial infections such as sepsis and meningitis, activation of inflammatory mediators such as nitric oxide (NO) plays a crucial role in both pathogenesis and host defense. We have previously reported that CNI-1493, a macrophage deactivator, reduced mortality in infant rats infected with Haemophilus influenzae type b (Hib) with associated decrease in the number of granulocytes in the infected tissue. The aim of the present study was to investigate how CNI-1493 affects granulocytes and macrophages in vitro. Murine macrophages (RAW 264.7) pre-incubated with CNI-1493 prior to activation with lipopolysaccharide (LPS)/interferon gamma (IFNgamma) had decreased NO production measured as NO(2)(-)/NO(3)(-) levels and reduction in inducible NO-synthase (iNOS) expression. Reactive oxygen species (ROS) production was increased in formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated granulocytes following CNI-1493 treatment, whereas F-actin content, motility and chemotaxis were decreased under the same conditions. The effects of CNI-1493 on both NO production in LPS/IFNgamma-activated macrophages and ROS production, F-actin content, motility and chemotaxis in granulocytes, may contribute to the reduced inflammatory response and increased survival in Hib-infected animals treated with CNI-1493.

Revisiting the immunomodulators tacrolimus, methotrexate, and mycophenolate mofetil: their mechanisms of action and role in the treatment of IBD

Inflammatory bowel diseases (IBDs) are thought to result from unopposed immune responses to normal gut flora in a genetically susceptible host. A variety of immunomodulating therapies are applied for the treatment of patients with IBDs. The first-line treatment for IBDs consists of 5-aminosalicylate and/or budesonide. However, these first-line therapies are often not suitable for continuous treatment or do not suffice for the treatment of severe IBD. Recently, efforts have been made to generate novel selective drugs that are more effective and have fewer side effects. Despite promising results, most of these novel drugs are still in a developmental stage and unavailable for clinical application. Yet, another class of established immunomodulators exists that is successful in the treatment of inflammatory bowel diseases. While waiting for emerging novel therapies, the use of these more established drugs should be considered. Furthermore, one of the advantages of using established immunomodulators is the well-documented knowledge on the long-term side effects and on the mechanisms of action. In this review, the authors discuss 3 well-known immunomodulators that are being applied with increased frequency for the treatment of IBD: tacrolimus, methotrexate, and mycophenolate mofetil. These agents have been used for many years as treatment modalities for immunosuppression after organ transplantation, for the treatment of cancer, and for immunomodulation in several other immune-mediated diseases. First, this review discusses the potential targets for immunomodulating therapies in IBDs. Second, the immunomodulating mechanisms and effects of the 3 immunomodulators are discussed in relationship to these treatment targets.

Semapimod Reduces the Depth of Injury Resulting in Enhanced Re-epithelialization of Partial-Thickness Burns in Swine

Studies suggest that tumor necrosis factor alpha (TNF-alpha) plays a role in burn pathogenesis. We conducted a randomized controlled experiment in swine to determine whether a novel macrophage inhibitor, semapimod (formerly known as CNI-1493), would blunt the local production of TNF-alpha, interleukin (IL)-1, and IL-6 in burns leading to less injury extension and faster re-epithelialization. After creating second-degree burns, animals received one or two intravenous boluses of semapimod 1 mg/kg or normal saline, and all burns were treated with silver sulfadiazine. The depth of follicular necrosis and thrombosis was reduced by either one or two doses of semapimod (P=.04 and .02, respectively). However, no differences were noted between groups in cytokine levels. Depth of scarring was similar in all groups. We conclude that Semapimod reduces the depth of follicular necrosis and thrombosis after second-degree burns in swine, indirectly resulting in more rapid re-epithelialization. However, this affect does not appear to be mediated by reduced local TNF-alpha, IL-1, or IL-6 protein levels.

Specific inhibition of c-Raf activity by semapimod induces clinical remission in severe Crohn's disease

There is a substantial need for novel treatment strategies in Crohn's disease (CD), a chronic relapsing inflammatory disease of the gut. In an earlier study, we reported clinical efficacy of a 2-wk treatment with semapimod (CNI-1493) in 12 patients with therapy resistant CD. The aim of this study was to identify the cellular target underlying semapimod action. In vitro experiments with murine macrophages showed impaired MAPK signaling and decreased cytokine production due to semapimod treatment. In vitro kinase assays revealed c-Raf as a direct molecular target of semapimod, and semapimod did not affect b-Raf enzymatic activity. Immunohistochemistry performed on paired colon biopsies obtained from CD patients (n = 6) demonstrated increased expression of phospho-MEK, the substrate of Raf. Strikingly, phospho-MEK levels were significantly decreased in patients with a good clinical response to semapimod, but no decrease in phospho-MEK expression was observed in a clinically nonresponsive patient. In conclusion, this study identifies c-Raf as a molecular target of semapimod action and suggests that decreased c-Raf activity correlates with clinical benefit in CD. Our observations indicate that c-Raf inhibitors are prime candidates for the treatment of CD.

Tumor necrosis factor as a pharmacological target

As indicated by its name, tumor necrosis factor (TNF), cloned in 1985, was originally described as a macrophage-derived endogenous mediator that can induce hemorrhagic necrosis of solid tumors and kill some tumor cell lines in vitro. Unfortunately, its promising use as an anticancer agent was biased by its toxicity, which was clear soon from the first clinical trials with TNF in cancer. Almost at the same time TNF was being developed as an anticancer drug, it became clear that TNF was identical to a mediator responsible for cachexia associated with sepsis, which was termed cachectin. This research led to the finding that TNF is, in fact, the main lethal mediator of sepsis and to the publication of a huge number of articles showing that TNF inhibits the toxic effects of bacterial endotoxins, which are now described as systemic inflammatory response. Although the clinical trials with anti-TNF in sepsis have not been successful thus far, undoubtedly as a result of the complexity of this clinical setting, these studies ultimately led to the identification of TNF as a key inflammatory mediator and to the development of anti-TNF molecules (soluble receptors and antibodies) for important diseases including rheumatoid arthritis and Crohn's disease. On the other side, the mechanisms by which TNF and related molecules induce cell death have been studied in depth, and their knowledge might, in the future, suggest means of improve the therapeutic index of TNF in cancer.

High-mobility group box 1 protein is an inflammatory mediator in necrotizing enterocolitis: protective effect of the macrophage deactivator semapimod

High-mobility group box 1 (HMGB1) is a late mediator of endotoxemia known to stimulate the production of proinflammatory cytokines that are putative mediators of intestinal inflammation associated with necrotizing enterocolitis (NEC). We hypothesized that HMGB1 is also involved in the pathogenesis of NEC. We examined the expression of HMGB1 and the effect of the novel drug semapimod on intestinal inflammation in an experimental model of NEC in neonatal rats. Newborn rats were subjected to hypoxia and fed a conventional formula by gavage (FFH) or were breast fed (BF). Rats were killed on day 4, and the distal ileum was harvested for morphological studies and Western blot analysis. FFH newborn rats but not BF controls developed intestinal inflammation similar to the histological changes observed in human NEC. We found that the expression of HMGB1 and its receptor for advanced glycation end products (RAGE) as well as that of other apoptosis/inflammation-related proteins (Bad, Bax, inducible nitric oxide synthase, and cyclooxygenase 2) was upregulated in the ileal mucosa of FFH newborn rats compared with BF animals. Administration of the drug semapimod inhibited the upregulation of those proteins and partially protected the animals against the FFH-induced intestinal injury. Elevated levels of HMGB1 were also found in ileal samples from infants undergoing intestinal resection for acute NEC. Our results implicate HMGB1 and RAGE as important mediators of enterocyte cell death and hypoxia-induced injury in NEC and support the hypothesis that inhibitors such as semapimod might play a therapeutic role in chronic intestinal inflammation characterized by this animal model.

Blockade of endogenous cytokines mitigates neointimal formation in obese Zucker rats

BACKGROUND

It is well known that diabetes mellitus is a major risk factor for vascular diseases such as atherosclerosis and restenosis after angioplasty. It has become clear that advanced glycation end products (AGE) and their receptor (RAGE) are implicated in vascular diseases, especially in diabetes mellitus. Nevertheless, the mechanisms by which diabetes mellitus is often associated with vascular diseases remain unclear.

METHODS AND RESULTS

To study the role of endogenous cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 in the development of vascular diseases and in the expression of RAGE, we used semapimod, a pharmacological inhibitor of cytokine production, and examined its effect on neointimal formation in the femoral artery of obese Zucker (OZ) rats. We also used an adenovirus construct expressing a dominant negative mutant of the receptor for TNF-alpha (AdTNFRDeltaC) to block the action of endogenous TNF-alpha. Semapimod significantly suppressed neointimal formation and RAGE expression in OZ rats compared with untreated OZ rats. This inhibitory effect of semapimod on neointimal formation was overcome by infection of an adenovirus expressing RAGE into the femoral artery of OZ rats. Furthermore, AdTNFRDeltaC infection significantly suppressed neointimal formation and RAGE expression in the femoral artery of OZ rats.

CONCLUSIONS

These results suggest that endogenous cytokines, especially TNF-alpha, were implicated in neointimal formation in OZ rats and that RAGE was a mediator of the effect of these cytokines on neointimal formation.

MAPK signalling pathways as molecular targets for anti-inflammatory therapy--from molecular mechanisms to therapeutic benefits

Excessive inflammation is becoming accepted as a critical factor in many human diseases, including inflammatory and autoimmune disorders, neurodegenerative conditions, infection, cardiovascular diseases, and cancer. Cerebral ischemia and neurodegenerative diseases are accompanied by a marked inflammatory reaction that is initiated by expression of cytokines, adhesion molecules, and other inflammatory mediators, including prostanoids and nitric oxide. This review discusses recent advances regarding the detrimental effects of inflammation, the regulation of inflammatory signalling pathways in various diseases, and the potential molecular targets for anti-inflammatory therapy. Mitogen-activated protein kinases (MAPKs) are a family of serine/threonine protein kinases that mediate fundamental biological processes and cellular responses to external stress signals. Increased activity of MAPK, in particular p38 MAPK, and their involvement in the regulation of the synthesis of inflammation mediators at the level of transcription and translation, make them potential targets for anti-inflammatory therapeutics. Inhibitors targeting p38 MAPK and JNK pathways have been developed, and preclinical data suggest that they exhibit anti-inflammatory activity. This review discusses how these novel drugs modulate the activity of the p38 MAPK and JNK signalling cascades, and exhibit anti-inflammatory effects in preclinical disease models, primarily through the inhibition of the expression of inflammatory mediators. Use of MAPK inhibitors emerges as an attractive strategy because they are capable of reducing both the synthesis of pro-inflammatory cytokines and their signalling. Moreover, many of these drugs are small molecules that can be administered orally, and initial results of clinical trials have shown clinical benefits in patients with chronic inflammatory disease.

Inhibition of tumor necrosis factor-alpha improves physiological angiogenesis and reduces pathological neovascularization in ischemic retinopathy

The present study was undertaken to test whether inhibition of the proangiogenic inflammatory cytokine tumor necrosis factor (TNF)-alpha can modulate retinal hypoxia and preretinal neovascularization in a murine model of oxygen-induced retinopathy (OIR). OIR was produced in TNF-alpha-/- and wild-type (WT) control C57B6 neonatal mice by exposure to 75% oxygen between postnatal days 7 and 12 (P7 to P12). Half of each WT litter was treated with the cytokine inhibitor semapimod (formerly known as CNI-1493) (5 mg/kg) by daily intraperitoneal injection from the time of reintroduction to room air at P12 until P17. The extent of preretinal neovascularization and intraretinal revascularization was quantified by image analysis of retinal flat-mounts and retinal hypoxia correlated with vascularization by immunofluorescent localization of the hypoxia-sensitive drug pimonidazole (hypoxyprobe, HP). HP adducts were also characterized by Western analysis and quantified by competitive enzyme-linked immunosorbent assay. TNF-alpha-/- and WT mice showed a similar sensitivity to hyperoxia-induced retinal ischemia at P12. At P13 some delay in early reperfusion was evident in TNF-alpha-/- and WT mice treated with semapimod. However, at P17 both these groups had significantly better vascular recovery with less ischemic/hypoxic retina and preretinal neovascularization compared to untreated retinopathy in WT mice. Immunohistochemistry showed deposition of HP in the avascular inner retina but not in areas underlying preretinal neovascularization, indicating that such aberrant vasculature can reduce retinal hypoxia. Inhibition of TNF-alpha significantly improves vascular recovery within ischemic tissue and reduces pathological neovascularization in OIR. HP provides a useful tool for mapping and quantifying tissue hypoxia in experimental ischemic retinopathy.

Macrophage inhibitor, semapimod, reduces tumor necrosis factor-alpha in myocardium in a rat model of ischemic heart failure

Pharmaceutical agents aimed at reducing tumor necrosis factor-alpha (TNF-alpha) levels appeared to be attractive possibilities in the medical management of heart failure, as heart failure was shown to be associated with high TNF-alpha levels. However, therapies specifically targeting TNF-alpha failed to show any survival benefit. We examined whether a broad inhibition of inflammatory cytokine production secondary to macrophage inhibition would be more effective at improving cardiac function in the setting of heart failure. To this end, we studied Semapimod (formerly known as CNI-1493), a synthetic guanylhydrazone that inhibits macrophage activation and the production of several inflammatory cytokines. Left anterior descending coronary ligation surgery was performed on each animal to induce a myocardial infarction. After confirming heart failure by echocardiography, the animals were randomly assigned to one of four groups: (1) rats with myocardial infarct receiving high-dose Semapimod, 10 mg/kg/d (MI-H, N = 13); (2) rats with myocardial infarct receiving low-dose Semapimod, 3 mg/kg/d (MI-L, N = 9); (3) rats with myocardial infarct receiving vehicle treatment, 2.5% mannitol in water (MI-0, N = 9); and (4) control rats with sham operation and vehicle treatment (Sham, N = 10). Both Semapimod and vehicle treatments were administered by daily tail vein injections over a course of five days. Echoes were repeated at 2, 5, and 9 weeks following treatment. At 9 weeks, hemodynamic data were collected and the animals were euthanized. Trichrome staining was done to assess infarct, and immunohistochemistry was performed to assess TNF-alpha levels. Prior to drug administration, serum was taken from 5 random rats. No detectable level of TNF-alpha was seen (lower limit of detection for the assay used = 12.5 pg/mL). Also prior to any treatment, echocardiography confirmed significant cardiac impairment of rats undergoing LAD ligation as compared with sham. Over the course of the 9 weeks, there were 4 deaths, all in the MI-H group. There was no difference between Semapimod-treated animals and vehicle-treated MI animals in any echocardiographic or hemodynamic parameter. TNF-alpha staining in the noninfarcted region was evident only in the MI groups, not the sham group. When blindly compared on a semiquantitative scale (ie, 0 = no visible staining to 3 = marked staining), a significant difference in staining was observed between MI-0 versus MI-H (1.19 +/- 0.32 versus 0.33 +/- 0.14; P = 0.03) and between MI-0 and MI-L (1.19 +/- 0.32 versus 0.39 +/- 0.22; P = 0.05). In this setting, despite the fact that Semapimod treatment decreased tissue TNF-alpha levels, it did not improve cardiac function, and at high doses it was associated with higher mortality. These results in a rodent model confirm the results of clinical trials with etanercept and infliximab (ie, that decreasing TNF levels in plasma or tissues does not improve cardiac function and may actually increase mortality).

Potential new therapies for the treatment of acute pancreatitis

The treatment of acute pancreatitis has remained virtually unchanged for the past 50 years, in large part due to a poor understanding of the initial intracellular events. Furthermore, there is a lack of knowledge regarding the mediator(s) responsible for the progression of the disease from local pancreatic inflammation to a systemic inflammatory disease, as well as the mediator(s) responsible for distant organ dysfunction and failure. With recent advances in the pathophysiology of pancreatitis, in particular the role of the inflammatory mediators interleukin-1 beta, tumour necrosis factor alpha and platelet-activating factor, the potential for new effective therapies has been realised. At present, a number of inflammatory mediator antagonists are being tested in humans, with the hope that we may soon develop a specific treatment for a disease, which thus far, has none.

Identification of cellular deoxyhypusine synthase as a novel target for antiretroviral therapy

The introduction of highly active antiretroviral therapy (HAART) has significantly decreased morbidity and mortality among patients infected with HIV-1. However, HIV-1 can acquire resistance against all currently available antiretroviral drugs targeting viral reverse transcriptase, protease, and gp41. Moreover, in a growing number of patients, the development of multidrug-resistant viruses compromises HAART efficacy and limits therapeutic options. Therefore, it is an ongoing task to develop new drugs and to identify new targets for antiretroviral therapy. Here, we identified the guanylhydrazone CNI-1493 as an efficient inhibitor of human deoxyhypusine synthase (DHS). By inhibiting DHS, this compound suppresses hypusine formation and, thereby, activation of eukaryotic initiation factor 5A (eIF-5A), a cellular cofactor of the HIV-1 Rev regulatory protein. We demonstrate that inhibition of DHS by CNI-1493 or RNA interference efficiently suppressed the retroviral replication cycle in cell culture and primary cells. We show that CNI-1493 inhibits replication of macrophage- and T cell-tropic laboratory strains, clinical isolates, and viral strains with high-level resistance to inhibitors of viral protease and reverse transcriptase. Moreover, no measurable drug-induced adverse effects on cell cycle transition, apoptosis, and general cytotoxicity were observed. Therefore, human DHS represents a novel and promising drug target for the development of advanced antiretroviral therapies, particularly for the inhibition of multidrug-resistant viruses.

The role of the AU-rich elements of mRNAs in controlling translation

Adenosine- and uridine-rich elements (AREs) located in 3'-untranslated regions are the best-known determinants of RNA instability. These elements have also been shown to control translation in certain mRNAs, including mRNAs for prominent pro-inflammatory and tumor growth-related proteins, and physiological anti-inflammatory processes that target ARE-controlled translation of mRNAs coding for pro-inflammatory proteins have been described. A major research effort is now being made to understand the mechanisms by which the translation of these mRNAs is controlled and the signalling pathways involved. This review focuses on the role of ARE-containing gene translation in inflammation, and the disease models that have improved our understanding of ARE-mediated translational control.

In vivo and in vitro cytokine modulatory activity of newly synthesised 2-aminotetraline derivatives

In the present study, the protective effect of newly synthesised 2-aminotetralines was investigated in murine models of toxic shock. A few derivatives protected mice against lethality induced by lipopolysaccharide from different bacterial strains and shock induced by staphylococcal enterotoxin B in mice sensitized by D-Galactosamine (D-Galn). Notably, one derivative, S(-)-2-amino-6-fluoro-7-methoxy-1,2,3,4 tetrahydronaphthalene hydrochloride (ST1214), was also effective when administered orally (30 mg kg-1) in a therapeutic regimen. ST1214 markedly inhibited the production of the proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), Interleukin-1beta (IL-1beta), Interleukin-12 (IL-12), interferon-gamma (IFN-gamma), as well as the inflammatory mediator nitric oxide (NO), and concurrently enhanced the production of the anti-inflammatory cytokine IL-10. Moreover, ST1214 dose-dependently reduced TNF-alpha production by human peripheral blood mononuclear cells and promonocytic THP-1 cells in vitro. In the latter, ST1214 was found to inhibit lipopolysaccharide-induced TNF-alpha secretion but not cytokine mRNA accumulation. These results suggest that the mechanism of action of ST1214 involves blockade of posttranscriptional events of TNF-alpha production, apparently independent of p38 and ERK kinase activity. These results show beneficial effects of 2-aminotetralines in murine shock models and indicate a distinct counter-regulatory activity in down-regulating proinflammatory cytokine response, and upregulating IL-10. One derivative, i.e., ST1214, can be regarded as a lead compound in the development of novel drugs effective in anti-inflammatory strategies.

CNI-1493 mediated suppression of dendritic cell activation in vitro and in vivo

The tetravalent guanylhydrazone CNI-1493 (CNI-1493) has been shown to inhibit macrophage activation, reduce systemic inflammation as well as proinflammatory cytokine production. Here we report for the first time that CNI-1493 also influences the biology of dendritic cells (DC). In order to become potent T cell stimulators of DC have to mature. Interestingly, when CNI-1493 was added to the maturation stimulus the expression of a typical DC-maturation marker i.e. CD83 was reduced. Subsequent functional in vitro analyses showed that DC-mediated T-cell stimulation was clearly reduced in CNI-1493-treated DC, underlining the functional impact that CNI-1493 on DC biology. Furthermore, the effect of CNI-1493 was analyzed in vivo using the experimental autoimmune encephalomyelitis (EAE) model in C57BL/6 mice. Interestingly, in a prophylactic treatment regimen CNI-1493 prevented the paralysis associated with EAE almost completely. In addition, when applied in an early therapeutic setting CNI-1493 also reduced the clinical EAE symptoms. In summary, we show for the first time, that in addition to the earlier reported effects on macrophages, CNI-1493 also influences the function and biology of DC. Since DC are the only antigen-presenting cells (APC) known today to be able to prime naive T cells, the findings reported herein are highly relevant for the therapeutic application of CNI-1493.

Macrophage participation in influenza-induced sleep enhancement in C57BL/6J mice

Mice develop changes in sleep during the nonspecific immune response that occurs during the initial few days after inoculation with influenza virus. T lymphocytes, neutrophils, macrophages, and natural killer (NK) cells all participate in the early host response to influenza infection. All of these cell types are potential sources of endogenous substances that modulate sleep, but the contributory role of each cell type to the alteration of somnolence during infection has not been determined. To investigate which cell types contribute to the sleep enhancement that develops during influenza infection in mice, the sleep patterns of C57BL/6J mice with perturbations of particular facets of host immune response capabilities were assessed before and after influenza infection. Targeted mutation of the gene Ccl3 (macrophage inflammatory protein 1 alpha) prevented development of the dark phase sleep enhancement that is characteristic of C57BL/6J mice after influenza infection. Other experimental treatments that impair macrophage or monocyte function also produced significant (administration of pentoxifylline or CNI-1493) or marginally significant (deletion of the interferon-gamma gene or intranasal administration of carrageenan) changes in influenza-induced sleep enhancement in C57BL/6J mice. In contrast, functional impairments of NK cells, neutrophils, and T lymphocytes did not significantly influence sleep responses. These data therefore support a contributory role for macrophages, but not for NK cells, neutrophils, and T lymphocytes, in eliciting the sleep response typical of influenza-infected C57BL/6J mice.