How much (evil) intelligence can be encoded by 30 kb?

Genomes of most RNA viruses are rarely larger than the size of an average human gene (10-15 kb) and still code for a number of biologically active polypeptides that modify the immune system and metabolism of the host organism in an amazingly complex way. Prolonged coevolution developed tricks by which viruses can dodge many protective mechanisms of the host and lead to the formation of molecular mimicry patterns. Some viruses inhibit the interferon response, interfere with the membrane destroying effects of the activated complement cascade. They can replicate in cellular compartments formed by inner membranes of the cell hiding their characteristic features from diverse pattern recognition receptors. In many cases-and in this respect, the new coronavirus is a champion-they can exploit our own defensive mechanisms to cause serious harm, severe symptoms and frequently deadly disease.

Visible Light-Generated Antiviral Effect on Plasmonic Ag-TiO2-Based Reactive Nanocomposite Thin Film.

The recent coronavirus pandemic pointed out the vulnerability of humanity to new emerging infectious diseases. Experts warn that future pandemics may emerge more frequently with greater devastating effects on population health and the world economy. Although viruses are unable to propagate on lifeless surfaces, they can retain their infectivity and spread further on contact with these surfaces. The objective of our study is to analyze photoreactive composite films that exert antiviral effects upon illumination. Reactive plasmonic titanium dioxide-based polymeric nanocomposite film was prepared with a thickness of 1-1.5 µm, which produces reactive oxygen species (ROS) under visible light irradiation (λ ≥ 435 nm). These species are suitable for photooxidation of adsorbed organic molecules (e.g., benzoic acid) on the nanocomposite surface. Moreover, high molecular weight proteins are also degraded or partially oxidized in this process on the composite surface. Since the Ag0-TiO2/polymer composite film used showed excellent reactivity in the formation of OH• radicals, the photocatalytic effect on high molecular weight (M = ∼66.000 Da) bovine serum albumin (BSA) protein was investigated. Given that changes in the structure of the protein were observed upon exposure to light, we assumed virucidal effect of the illuminated photoreactive composite film. We tested this hypothesis using an airborne-transmitted herpesvirus. As a result, we obtained a drastic decrease in infection capability of the virus on the photoreactive surface compared to the control surface.

Opportunity of periodic monitoring of COVID-19 patients, asymptomatic virus carriers, and postinfectious individuals with IgM/IgG rapid antibody tests among healthcare workers during SARS-CoV-2 pandemic. / A COVID-19-betegek, tünetmentes hordozók, illetve a betegségen már átesettek periodikus monitorizálási lehetosége IgM/IgG antitest alapú gyorstesztekkel az egészségügyi személyzet körében a SARS-CoV-2-járvány idején.

The first Hungarian COVID-19 case was reported on March 4, 2020 by Hungarian officials. Healthcare workers (HCWs) are at the highest risk of contracting the novel coronavirus (SARS-CoV-2), with 12% of total coronavirus cases confirmed among them recently. 80% of the infected persons show only mild, moderate symptoms or stay asymptomatic. The single-stranded viral RNA can be detected by RT-PCR from the respiratory tract, urine, blood and, particulary in children, from stool samples for 30-40 days. We have no valid data of how many HCWs have been infected since the Hungarian SARS-CoV-2 outbreak, due to the lack of the systematic screening. HCWs could play a critical role in transmission and might jeopardize the health of both their patients and their own family members. Both cross-sectional and longitudinal sudies are recommended to evaluate the ratio of the recovered, i.e., "already protected", the ones in the acute phase, i.e., "the infectious", and the virus-naive, i.e., "at risk" workers. Of the available molecular diagnostic options, in addition to RT-PCR it would be advisable to introduce the novel rapid antibody tests which can give quick results, reveal the timeline of the infection, are easy to handle, inexpensive and can be used periodically to monitor HCWs' viral status during the still unkown duration of the SARS-CoV-2 pandemic. Orv Hetil. 2020; 161(21): 854-860.

Contribution of syndecans to lipoplex-mediated gene delivery.

The long awaited breakthrough of gene therapy significantly depends on the in vivo efficiency of targeted intracellular delivery. Hidden details of cellular uptake present a great hurdle for non-viral gene delivery with liposomes. Growing scientific evidence supports the involvement of polyanionic cell surface carbohydrates in cellular internalization of cationic liposomes. Syndecans, a highly conserved family of transmembrane heparan sulfate proteoglycans serve attachment sites for great variety of cationic ligands including growth factors, cytokines and even parasites. In the present study we quantitatively measured the contribution of various syndecan isoforms to liposome-mediated gene transfer. The obtained data show the superiority of syndecan-4, the ubiquitously expressed isoform of the syndecan family, in cellular uptake of liposomes. Applied mutational analysis demonstrated that gene delivery could be abolished by mutating the glycosaminoglycan attachment site of syndecans, highlighting the importance of polyanionic heparan sulfate side chains in the attachment of cationic liposomes. Blocking sulfation of syndecans also diminished gene delivery, a finding that confirms the essential role of polyanionic charges in binding cationic liposomes. Mutating other parts of the syndecan extracellular domain, including the cell-binding domain, had clearly smaller effect on liposome internalization. Mutational analyses also revealed that superiority of syndecan-4 in liposome-mediated gene delivery is significantly influenced by its cytoplasmic domain that orchestrates signaling pathways leading to macropinocytosis. In summary our study present a mechanistic insight into syndecan-mediated macropinocytic uptake of lipoplexes and highlights syndecan-4 as a superior target for cationic liposomes.

Importance of reverse signaling of the TNF superfamily in immune regulation.

TNF-related ligands (with the exception of lymphotoxin-α) are synthesized as type II transmembrane proteins, though many of them also have soluble forms. An increasing number of publications report that these 'ligands' behave as receptors, activating intracellular signaling pathways when interacting with cognate 'receptors' or agonistic antibodies. Most members of the TNF family and their receptors influence survival, proliferation, differentiation or activation of immune cells. The elicited 'reverse signals' also have significant importance. They proved to be involved in the activation of APCs, T and B cells, differentiation of osteoclasts and apoptosis of activated macrophages. They influence the balance between destructive immune response and tolerance. Several examples show that therapeutic manipulation of the reverse signal can help to treat malignancies as well as autoimmune disorders.

Casein kinase 2-interacting protein-1, an inflammatory signaling molecule interferes with TNF reverse signaling in human model cells.

When transmembrane form of tumor necrosis factor (mTNF) interacts with its cognate receptors or agonistic antibodies signaling pathways are activated in the ligand expressing cells. This "reverse signaling" appears a fine-tuning control mechanism in the immune response. Despite a clinical relevance key molecules of TNF reverse signaling and their functions remain elusive. We examined the role of CKIP-1, an interacting partner of the N terminal fragment of mTNF in inflammation and TNF reverse signaling. We found that CKIP-1 expression was elevated upon LPS challenge in THP-1 human monocyte model cells. Overexpression of CKIP-1 triggered classical activation of THP-1 cells and transactivated the human TNF promoter when co-expressed with c-Jun in the HEK293 model system. TNF reverse signaling induced a massive translocation of CKIP-1 from the plasma membrane to intracellular compartments in THP-1 cells. Expression of the N terminal fragment of mTNF in HEK293 cells resembled the effects of TNF reverse signaling with respect to relocalization of CKIP-1. In parallel with the translocation, CKIP-1-triggered activation of THP-1 cells was antagonized by TNF reverse signaling. Similarly, the presence of the N terminal fragment of mTNF inhibited CKIP-1 mediated TNF promoter activation in HEK293 cells. Both TNF reverse signaling in THP-1 cells and expression of the N terminal fragment of mTNF in HEK293 cells were found to induce apoptosis that could be prevented by overexpression of CKIP-1. Our findings demonstrate that CKIP-1 activates pro-inflammatory pathways and interferes with TNF reverse signaling induced apoptosis in human model cells.

Lysosomal rerouting of Hsp70 trafficking as a potential immune activating tool for targeting melanoma.

Tumor specific cell surface localization and release of the stress inducible heat shock protein 70 (Hsp70) stimulate the immune system against cancer cells. A key immune stimulatory function of tumor-derived Hsp70 has been exemplified with the murine melanoma cell model, B16 overexpressing exogenous Hsp70. Despite the therapeutic potential mechanism of Hsp70 transport to the surface and release remained poorly understood. We investigated principles of Hsp70 trafficking in B16 melanoma cells with low and high level of Hsp70. In cells with low level of Hsp70 apparent trafficking of Hsp70 was mediated by endosomes. Excess Hsp70 triggered a series of changes such as a switch of Hsp70 trafficking from endosomes to lysosomes and a concomitant accumulation of Hsp70 in lysosomes. Moreover, lysosomal rerouting resulted in an elevated concentration of surface Hsp70 and enabled active release of Hsp70. In fact, hyperthermia, a clinically applicable approach triggered immediate active lysosomal release of soluble Hsp70 from cells with excess Hsp70. Furthermore, excess Hsp70 enabled targeting of internalized surface Hsp70 to lysosomes, allowing in turn heat-induced secretion of surface Hsp70. Altogether, we show that excess Hsp70 expressed in B16 melanoma cells diverts Hsp70 trafficking from endosomes to lysosomes, thereby supporting its surface localization and lysosomal release. Controlled excess-induced lysosomal rerouting and secretion of Hsp70 is proposed as a promising tool to stimulate anti-tumor immunity targeting melanoma.

Interactions between LPS moieties and macrophage pattern recognition receptors.

Mammalian host organisms live their life constantly interacting with pathogenic and non-pathogenic Gram-negative bacteria. Commensal/symbiont strains are tolerated in the gut, while pathogens are kept at bay by the immune system. In contrast both commensals and pathogenic bacteria are targets of the immune system outside of the digestive system. Immune cells are activated upon contact with different constituents of bacterial cells like peptidoglycan, outer membrane proteins, fimbriae, bacterial DNA, etc. One of the dominant molecular targets affecting the immune cells is the lipopolysaccharide (LPS), an essential molecule of the cell wall of Gram-negative bacteria. In this review we discuss interactions of macrophages with the main LPS moieties lipid A, core and O-antigen regions.

Melanoma cell-derived exosomes alter macrophage and dendritic cell functions in vitro.

To clarify controversies in the literature of the field, we have purified and characterized B16F1 melanoma cell derived exosomes (mcd-exosomes) then we attempted to dissect their immunological activities. We tested how mcd-exosomes influence CD4+ T cell proliferation induced by bone marrow derived dendritic cells; we quantified NF-κB activation in mature macrophages stimulated with mcd-exosomes, and we compared the cytokine profile of LPS-stimulated, IL-4 induced, and mcd-exosome treated macrophages. We observed that mcd-exosomes helped the maturation of dendritic cells, enhancing T cell proliferation induced by the treated dendritic cells. The exosomes also activated macrophages, as measured by NF-κB activation. The cytokine and chemokine profile of macrophages treated with tumor cell derived exosomes showed marked differences from those induced by either LPS or IL-4, and it suggested that exosomes may play a role in the tumor progression and metastasis formation through supporting tumor immune escape mechanisms.

Effects of Kupffer cell blockade on the hepatic expression of metallothionein and heme oxygenase genes in endotoxemic rats with obstructive jaundice.

AIMS: Heme oxygenase (HO) and metallothionein (MT) genes are rapidly upregulated in the liver by pro-inflammatory cytokines and/or endotoxin as protection against cellular stress and inflammation. Gadolinium chloride (GdCl3)-induced Kupffer cell blockade has beneficial consequences in endotoxemia following bile duct ligation. Herein we further characterized the effects of Kupffer cell inhibition on the activation of the antioxidant defense system (HO and MT gene expressions, and antioxidant enzyme activities) in response to endotoxemia and obstructive jaundice. MAIN METHODS: The isoform-specific expression of MT and HO genes was assessed (RT-PCR) in rat livers following 3-day bile duct ligation, 2-h lipopolysaccharide treatment (1mg/kg) or their combination, with or without GdCl3 pretreatment (10 mg/kg, 24h before endotoxin). Lipid peroxidation, DNA damage and hepatic antioxidant enzyme activities were also assessed. KEY FINDINGS: All these challenges induced similar extents of DNA damage, whereas the lipid peroxidation increased only when endotoxemia was combined with biliary obstruction. The MT and HO mRNA levels displayed isoform-specific changes: those of MT-1 and HO-2 did not change appreciably, whereas those of MT-2 and HO-1 increased significantly in 2-h endotoxemia, with or without obstructive jaundice. Among the enzymes reflecting the endogenous protective mechanisms, the catalase and copper/zinc-superoxide dismutase levels decreased, while that of Mn-SOD slightly increased. Interestingly, GdCl3 alone induced lipid peroxidation, DNA damage and MT-2 expression. In response to GdCl3, HO-1 induction was significantly lower in each model. SIGNIFICANCE: Despite its moderate hepatocellular toxicity, the ameliorated stress-induced hepatic reactions provided by GdCl3 may contribute to its protective effects.

[Consequences of Kupffer cell blockade on endotoxin-induced inflammatory and hepatic microcirculatory reactions during experimental biliary obstruction]. / A Kupffer-sejt gátlásának hatása az endotoxin indukálta gyulladásos válaszreakciókra és a máj mikrokeringési változásaira kísérletes obstructiós icterusban.

INTRODUCTION/AIMS: In the clinical practice, biliary obstruction often leads to septic complications causing systemic and hepatic inflammatory reactions, which increases mortality and morbidity. Hepatic Kupffer cells (KC) play a pivotal role in this process. Herein we examined the consequences of bile duct ligation during endotoxaemia and the effects of KCs. MATERIAL AND METHODS: In the first part of our experiment, the survival rate of male Wistar rats in 48-hr endotoxaemia with or without bile duct ligation was assessed. Time-dependent changes in pro-inflammatory TNF-alpha and IL-6 levels were also monitored. In the second series, hepatic capillary perfusion, neutrophil-endothelial interactions and KC activity were assessed using fluorescence intravital videomicroscopy. KC blockade was induced by gadolinium chloride (GdCl3) pretreatment. RESULTS: Serum TNF-alpha and IL-6 levels were significantly increased in early endotoxaemia. Survival rate was deteriorated, while TNF-alpha and IL-6 releases, KC activity and leukocyte activation were increased if obstructive jaundice was also induced. KC blockade improved survival and reduced TNF-alpha and IL-6 productions without ameliorating perfusion failure. CONCLUSIONS: In the presence of biliary obstruction, inflammatory and microcirculatory consequences of endotoxaemia are enhanced. The alleviating effect of KC blockade may underline the pathophysiological role of KCs in these conditions.

The role of lipopolysaccharide moieties in macrophage response to Escherichia coli.

Lipopolysaccharide (LPS) is the main component of Gram-negative bacteria that - upon infection - activates the host immune system and is crucial in fighting pathogens as well as in the induction of sepsis. In the present study we addressed the question whether the key structural components of LPS equally take part in the activation of different macrophage immune responses. By genomic modifications of Escherichia coli MG1655, we constructed a series of strains harboring complete and truncated forms of LPS in their cell wall. These strains were exposed to RAW 264.7 macrophages, after which phagocytosis, fast release of pre-synthesized TNF and activation of NF-kappaB signal transduction pathway were quantified. According to our results the core and lipid A moieties are involved in immune recognition. The most ancient part, lipid A is crucial in evoking immediate TNF release and activation of NF-kappaB. The O-antigen inhibits phagocytosis, leading to immune evasion.

Expression of immunoregulatory tumor necrosis factor-like molecule TL1A in chicken chondrocyte differentiation.

The proinflammatory cytokine tumor necrosis factor (TNF) alpha is not encoded in the chicken genome. However, 1 member of the TNF family, TNF-like molecule 1A (TL1A), which is an important immunoregulatory protein, has recently been characterized in chickens. In this study, chicken TL1A (chTL1A) and 1 of its receptors, decoy receptor 3 (DcR3) were found to be expressed in developing bone of 14.5-day-old chicken embryos. Chicken chondrocytes were shown to express TL1A by polymerase chain reaction (PCR) amplification of cDNA and by immunohistochemical studies. Tissue expression was localized to the epiphyeal region of tubular bones, particularly cells of the epiphyseal plate, the outer chondrocytes of the cartilage-interfacing synovia, most of the synovial cells, and the stromal fibroblastic cells of the vascular channels of the femoral head. A tissue-specific developmental function of TL1A was supported by the presence of DcR3 in the embryonic connective tissue.

Tribbles-2 is a novel regulator of inflammatory activation of monocytes.

Inflammatory activation of monocytes is an essential part of both innate immune responses and the pathogenesis of conditions such as atherosclerosis. However, the mechanisms which modulate the response of monocytes to inflammatory stimuli are still poorly understood. Here, we report that tribbles-2 (trb-2) is a novel regulator of inflammatory activation of monocytes. Down-regulation of trb-2 levels potentiates LPS-induced IL-8 production via enhanced activation of the extracellular signal-regulated kinase and jun kinase mitogen-activated protein kinase (MAPK) pathways. In keeping with this, the endogenous level of trb-2 expression in human primary monocytes is inversely correlated to the cell's ability to produce IL-8. We show that trb-2 is a binding partner and a negative regulator of selected MAPKs. The potential in vivo relevance of these findings is highlighted by the observation that modified low-density lipoprotein profoundly down-regulates trb-2 expression, which may, in turn, significantly contribute to the inflammatory processes in the development of vascular disease. Taken together, our results define trb-2 as a potent novel regulator of monocyte biology, controlling the activation of these cells.

Kupffer cell blockade improves the endotoxin-induced microcirculatory inflammatory response in obstructive jaundice.

Cholestasis predisposes to hypersensitivity to LPS, leading to potential septic complications. We set out to characterize the involvement of Kupffer cell (KC) activation in the hepatic microcirculatory and structural consequences of obstructive jaundice in the presence and absence of acute endotoxemia. The hepatic microcirculatory consequences of 3-day extrahepatic bile duct ligation (BDL) were assessed in rats. The contributions of changes in hepatic perfusion, leukocyte influx, and proinflammatory cytokine release to the development of hepatic structural damage were also determined. Furthermore, the corresponding consequences of BDL in combination with acute (2-h) endotoxemia (1 mg kg(-1) LPS, i.v.) were compared with those observed after LPS alone. In a second series, the same protocols were applied in identical groups of rats where the KC function was inhibited with 24-h gadolinium chloride pretreatment (10 mg kg(-1), i.v.). Bile duct ligation induced minor inflammatory reactions but caused a marked reduction in hepatic sinusoidal perfusion and severe histological damage. LPS treatment, however, elicited an approximately 5-fold increase in leukocyte adherence in the central venules and pronounced IL-6 and TNF-alpha release, but without significant structural damage. The combination of BDL with LPS enhanced the perfusion failure, leukocyte sticking/deposition, and proinflammatory cytokine release; most of these changes can be effectively ameliorated by gadolinium chloride. In conclusion, when obstructive jaundice is followed by a second hit of LPS, perfusion failure, liver inflammation, and structural damage are enhanced, the KCs playing a decisive role in this scenario. Therapeutic strategies aimed at KC blockade can potentially reduce the risk of inflammatory complications in cholestasis.

Effects of glucocorticoid agonist and antagonist on the pathogenesis of L-arginine-induced acute pancreatitis in rat.

OBJECTIVES: To investigate the consequences of treatment with an exogenous glucocorticoid agonist (methylprednisolone) and antagonist (RU-38486) on the local and systemic responses in L-arginine-induced acute pancreatitis in rats. METHODS: The methylprednisolone and RU-38486 were administered just before pancreatitis induction. Plasma amylase activity, interleukin 6 activity, pancreatic weight/body weight ratio, plasma macrophage migration inhibitory factor (MIF) concentration, and pancreatic nuclear transcription factor (NF) kappaB activity were determined. The extents of pancreas, liver, and lung injuries were assessed by histology. RESULTS: Acute pancreatitis resulted in NF-kappaB activation and proinflammatory cytokine release in rats. In the glucocorticoid agonist group, plasma amylase and interleukin 6 levels were significantly decreased as compared with those of RU-38486 and nontreated groups. Antagonist treatment led to significantly higher MIF production at 8 and 12 hours after L-arginine injection as compared with the agonist-treated and nontreated groups. Glucocorticoid agonist treatment significantly decreased the level of NF-kappaB 24 hours after pancreatitis induction. Histological investigations showed protective effect of agonist treatment on acute pancreatitis-induced tissue damage in the pancreas and lung. CONCLUSIONS: These results corroborated the importance of MIF in acute pancreatitis. The glucocorticoid-dependent mechanisms seem to play a crucial role in the control of the inflammatory response and tissue damage in L-arginine-induced experimental acute pancreatitis.

Gene expression dynamics in deer antler: mesenchymal differentiation toward chondrogenesis.

Annual re-growth of deer antler represents a unique example of complete organ regeneration. Because antler mesenchymal cells retain their embryonic capacity to develop into cartilage or bone, studying antler development provides a natural system to follow gene expression changes during mesenchymal differentiation toward chondrogenic/osteogenic lineage. To identify novel genes involved either in early events of mesenchymal cell specialization or in robust bone development, we have introduced a 3 K heterologous microarray set-up (deer cDNA versus mouse template). Fifteen genes were differentially expressed; genes for housekeeping, regulatory functions (components of different signaling pathways, including FGF, TGFbeta, Wnt), and genes encoding members of the Polycomb group were represented. Expression dynamics for genes are visualized by an expression logo. The expression profile of the gene C21orf70 of unknown function is described along with the effects when over-expressed; furthermore the nuclear localization of the cognate protein is shown. In this report, we demonstrate the particular advantage of the velvet antler model in bone research for: (1) identification of mesenchymal and precartilaginous genes and (2) targeting genes upregulated in robust cartilage development.

In vitro and in vivo nuclear factor-kappaB inhibitory effects of the cell-penetrating penetratin peptide.

Penetratin is a cationic cell-penetrating peptide that has been frequently used for the intracellular delivery of polar bioactive compounds. Recent studies have just revealed the major role of polyanionic membrane proteoglycans and cholesterol-enriched lipid rafts in the uptake of the peptide. Both proteoglycans and lipid-rafts influence inflammatory processes by binding a wide array of proinflammatory mediators; thus, we decided to analyze the effect of penetratin on in vitro and in vivo inflammatory responses. Our in vitro luciferase gene assays demonstrated that penetratin decreased transcriptional activity of nuclear factor-kappaB (NF-kappaB) in tumor necrosis factor (TNF)-stimulated L929 fibroblasts and lipopolysaccharide-activated RAW 264.7 macrophages. Penetratin also inhibited TNF-induced intercellular adhesion molecule-1 expression in human endothelial HMEC-1 cells. Exogenous heparan sulfate abolished the in vitro NF-kappaB inhibitory effects of the peptide. Uptake experiments showed that penetratin was internalized by all of the above-mentioned cell lines in vitro and rapidly entered the cells of the lung and pancreas in vivo. In an in vivo rat model of acute pancreatitis, a disease induced by elevated activities of stress-responsive transcription factors like NF-kappaB, pretreatment with only 2 mg/kg penetratin attenuated the severity of pancreatic inflammation by interfering with IkappaB degradation and subsequent nuclear import of NF-kappaB, inhibiting the expression of proinflammatory genes and improving the monitored laboratory and histological parameters of pancreatitis and associated oxidative stress.

Pentoxifylline and its major oxidative metabolites exhibit different pharmacological properties.

Previous investigations indicate that some of the metabolites of the hemorheological agent pentoxifylline (PTX), namely 1-(5-hydroxyhexyl)-3,7-dimethylxanthine (M1), 1-(4-carboxybutyl)-3,7-dimethylxanthine (M4) and 1-(3-carboxypropyl)-3,7-dimethylxanthine (M5), concur to some of the biological effects of the drug. However, information on the bioactivity of the major circulating oxidative metabolites of PTX (M4 and M5) is scanty. Here, we compared the effects of M4 and M5 with that of PTX and its major reductive metabolite, M1, on TNF-alpha production and cytotoxicity, endothelial cell proliferation and on the ATPase activity related to some ATP-binding cassette (ABC) transporters. Unlike PTX and M1, M4 and M5 poorly inhibited lipopolysaccaride-stimulated tumor necrosis factor-alpha (TNF-alpha) release by RAW 264.7 murine macrophages, and did not affect at all cell proliferation and upregulation of TNF-alpha-induced vascular cell adhesion molecule-1 (VCAM-1) in H5V endothelioma cells. By contrast, M4 and M5 were more effective than PTX and M1 in protecting WC/1 murine fibrosarcoma cells from TNF-alpha cytotoxicity. Moreover, results from ATP hydrolase assays indicated that neither PTX nor its tested metabolites interacted significantly with the human multidrug resistance transporters p-glycoprotein/multidrug resistance 1 (MDR1), multidrug resistance-related protein 1 (MRP1), and breast cancer resistance protein (BCRP). Based on these results and literature data, M5, retaining some of the PTX effects but lacking in significant inhibition of TNF-alpha production, may be a promising candidate drug for certain pathologic conditions.

The proteasome inhibitor MG132 protects against acute pancreatitis.

The cell-permeant MG132 tripeptide (Z-Leu-Leu-Leu-aldehyde) is a peptide aldehyde proteasome inhibitor that also inhibits other proteases, including calpains and cathepsins. By blocking the proteasome, this tripeptide has been shown to induce the expression of cell-protective heat shock proteins (HSPs) in vitro. Effects of MG132 were studied in an in vivo model of acute pancreatitis. Pancreatitis was induced in male Wistar rats by injecting 2 x 100 microug/kg cholecystokinin octapeptide intraperitoneally (ip) at an interval of 1 h. Pretreating the animals with 10 mg/kg MG132 ip before the induction of pancreatitis significantly inhibited IkappaB degradation and subsequent activation of nuclear factor-kappaB (NF-kappaB). MG132 also increased HSP72 expression. Induction of HSP72 and inhibition of NF-kappaB improved parameters of acute pancreatitis. Thus MG132 significantly decreased serum amylase, pancreatic weight/body weight ratio, pancreatic myeloperoxidase activity, proinflammatory cytokine concentrations, and the expression of pancreatitis-associated protein. Parameters of oxidative stress (GSH, MDA, SOD, etc.) were improved in both the serum and the pancreas. Histopathological examinations revealed that pancreatic specimens of animals pretreated with the peptide demonstrated milder edema, cellular damage, and inflammatory activity. Our findings show that simultaneous inhibition of calpains, cathepsins, and the proteasome with MG132 prevents the onset of acute pancreatitis.