Cysteine-type cathepsins promote the effector phase of acute cutaneous delayed-type hypersensitivity reactions.

Cysteine-type cathepsins such as cathepsin B are involved in various steps of inflammatory processes such as antigen processing and angiogenesis. Here, we uncovered the role of cysteine-type cathepsins in the effector phase of T cell-driven cutaneous delayed-type hypersensitivity reactions (DTHR) and the implication of this role on therapeutic cathepsin B-specific inhibition. Methods: Wild-type, cathepsin B-deficient (Ctsb-/-) and cathepsin Z-deficient (Ctsz-/-) mice were sensitized with 2,4,6-trinitrochlorobenzene (TNCB) on the abdomen and challenged with TNCB on the right ear to induce acute and chronic cutaneous DTHR. The severity of cutaneous DTHR was assessed by evaluating ear swelling responses and histopathology. We performed fluorescence microscopy on tissue from inflamed ears and lymph nodes of wild-type mice, as well as on biopsies from psoriasis patients, focusing on cathepsin B expression by T cells, B cells, macrophages, dendritic cells and NK cells. Cathepsin activity was determined noninvasively by optical imaging employing protease-activated substrate-like probes. Cathepsin expression and activity were validated ex vivo by covalent active site labeling of proteases and Western blotting. Results: Noninvasive in vivo optical imaging revealed strong cysteine-type cathepsin activity in inflamed ears and draining lymph nodes in acute and chronic cutaneous DTHR. In inflamed ears and draining lymph nodes, cathepsin B was expressed by neutrophils, dendritic cells, macrophages, B, T and natural killer (NK) cells. Similar expression patterns were found in psoriatic plaques of patients. The biochemical methods confirmed active cathepsin B in tissues of mice with cutaneous DTHR. Topically applied cathepsin B inhibitors significantly reduced ear swelling in acute but not chronic DTHR. Compared with wild-type mice, Ctsb-/- mice exhibited an enhanced ear swelling response during acute DTHR despite a lack of cathepsin B expression. Cathepsin Z, a protease closely related to cathepsin B, revealed compensatory expression in inflamed ears of Ctsb-/- mice, while cathepsin B expression was reciprocally elevated in Ctsz-/- mice. Conclusion: Cathepsin B is actively involved in the effector phase of acute cutaneous DTHR. Thus, topically applied cathepsin B inhibitors might effectively limit DTHR such as contact dermatitis or psoriasis. However, the cathepsin B and Z knockout mouse experiments suggested a complementary role for these two cysteine-type proteases.

Inhibition of 5-lipoxygenase and skin inflammation by the aerial parts of Artemisia capillaris and its constituents.

The aerial parts of Artemisia capillaris Thunberg (Compositae) have been used in Chinese medicine as a liver protective agent, diuretic, and for amelioration of skin inflammatory conditions. This study was conducted to establish the scientific rationale for treating skin inflammation and to find active principles from A. capillaris. To accomplish these goals, the 70% ethanol extract of the aerial parts of A. capillaris (AR) was prepared and its 5-lipoxygenase (5-LOX) inhibitory action was studied since 5-LOX products are known to be involved in several allergic and skin inflammatory disorders. AR showed potent inhibitory activity against 5-LOX-catalyzed leukotriene production by ionophore-induced rat basophilic leukemia-1 cells, with an IC(50) of < 1.0 µg/mL. Nine major compounds, scopoletin, scopolin, scoparone, esculetin, quercetin, capillarisin, isorhamnetin, 3-O-robinobioside, isorhamnetin 3-O-galactoside and chlorogenic acid, were isolated from A. capillaris, and their effects were examined to identify the active principle(s). Several coumarin and flavonoid derivatives were found to be 5-LOX inhibitors. In particular, esculetin and quercetin were potent inhibitors, with IC(50) values of 6.6 and 0.7 µM, respectively. Against arachidonic acid-induced ear edema in mice, AR, and esculetin strongly inhibited edematic response. AR and esculetin also inhibited delayed-type hypersensitivity response in mice. In conclusion, AR and some of their major constituents are 5-LOX inhibitors, and these in vitro and in vivo activities may contribute to the therapeutic potential of AR in skin inflammatory disorders in traditional medicine.

Involvement of tyrosine kinase-2 in both the IL-12/Th1 and IL-23/Th17 axes in vivo.

Tyrosine kinase-2 (Tyk2), a member of the Jak family of kinases, mediates the signals triggered by various cytokines, including type I IFNs, IL-12, and IL-23. In the current study, we investigated the in vivo involvement of Tyk2 in several IL-12/Th1- and IL-23/Th17-mediated models of experimental diseases, including methylated BSA injection-induced footpad thickness, imiquimod-induced psoriasis-like skin inflammation, and dextran sulfate sodium- or 2,4,6-trinitrobenzene sulfonic acid-induced colitis. In these disease models, Tyk2 deficiency influenced the phenotypes in immunity and/or inflammation. Our findings demonstrate a somewhat broader contribution of Tyk2 to immune systems than previously expected and suggest that Tyk2 may represent an important candidate for drug development by targeting both the IL-12/Th1 and IL-23/Th17 axes.

The p110 delta isoform of phosphatidylinositol 3-kinase controls the quality of secondary anti-Leishmania immunity by regulating expansion and effector function of memory T cell subsets.

We showed previously that mice with an inactivating knockin mutation in the p110delta isoform of PI3K (referred to as p110delta(D910A) mice) displayed enhanced primary resistance to Leishmania major despite mounting paradoxically impaired T cell responses. In this study, we show that p110delta(D910A) mice are impaired in their secondary (memory) anti-Leishmania responses in vitro and in vivo. Following secondary L. major challenge, p110delta(D910A) mice exhibited reduced delayed-type hypersensitivity response and weaker parasite control compared to wild-type mice. Using adoptive transfer experiments, we show that immune T cells from healed p110delta(D910A) mice were impaired in their proliferation and effector cytokine (IFN-gamma) responses upon L. major challenge. Interestingly, Leishmania-reactive T cells from healed p110delta(D910A) mice contain severalfold lower numbers of CD62L(lo) and CD62(hi) T cells than those from healed wild-type mice. The reduction in numbers of CD62L(lo) T cells in p110delta(D910A) mice is due to failure of their CD62L(hi) T cells to downregulate CD62L expression in response to L. major. Furthermore, although CD62L(lo) cells from p110delta(D910A) mice could home efficiently to lymphoid organs, their ability to exit these tissues and emigrate to cutaneous sites of infection was greatly impaired. Collectively, our data identify PI3K signaling as important events that control memory T cell subset differentiation, generation, effector function, and recruitment to cutaneous tissues and suggest that manipulating this pathway could provide means of enhancing desired memory T cell subset, response during vaccination, or both.

Therapeutic effect of exosomes from indoleamine 2,3-dioxygenase-positive dendritic cells in collagen-induced arthritis and delayed-type hypersensitivity disease models.

OBJECTIVE: We have demonstrated previously that dendritic cells (DCs) modified with immunosuppressive cytokines, and exosomes derived from DCs can suppress the onset of murine collagen-induced arthritis (CIA) and reduce the severity of established arthritis. Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-degrading enzyme that is important for immune regulation and tolerance maintenance. DCs expressing functional IDO can inhibit T cells by depleting them of essential tryptophan and/or by producing toxic metabolites, as well as by generating Treg cells. This study was undertaken to examine the immunosuppressive effects of bone marrow (BM)-derived DCs genetically modified to express IDO, and of exosomes derived from IDO-positive DCs. METHODS: BM-derived DCs were adenovirally transduced with IDO or CTLA-4Ig (an inducer of IDO), and the resulting DCs and exosomes were tested for their immunosuppressive ability in the CIA and delayed-type hypersensitivity (DTH) murine models. RESULTS: Both DCs and exosomes derived from DCs overexpressing IDO had an antiinflammatory effect in CIA and DTH murine models. The suppressive effects were partially dependent on B7 costimulatory molecules. In addition, gene transfer of CTLA-4Ig to DCs resulted in induction of IDO in the DCs and in exosomes able to reduce inflammation in an IDO-dependent manner. CONCLUSION: These results demonstrate that both IDO-expressing DCs and DC-derived exosomes are immunosuppressive and antiinflammatory, and are able to reverse established arthritis. Therefore, exosomes from IDO-positive DCs may represent a novel therapy for rheumatoid arthritis.

[Influence repeated stress on immune responciveness and monooxigenase activity of normotensive and hypertensive rats].

Repeated stress led to antipodal directions in immune system and cytochrome P450 activities of normotensive and hypertensive rats. Enhancement of the Reaction of Delayed Hypersensitivity, suppression of cytochrome P450-mediated monooxigenase activities were observed in Wistar rats. On the contrary, in the NISAG decrease of the Reaction Delayed Hypersensitivity, elevation of cytochrome P450-mediated monooxigenase activities were observed, as comparison with Wistar rats.

Indoleamine 2,3-dioxygenase (IDO) is involved in promoting the development of anterior chamber-associated immune deviation.

Indoleamine 2,3-dioxygenase (IDO), a rate-limiting enzyme in the tryptophan catabolism, has been shown to play an important role in various forms of immune tolerance. Since anterior chamber associated immune deviation (ACAID) is a systemic immune tolerance elicited by introducing exogenous antigens into the anterior chamber of the eye, we investigated the expression and function of IDO in the development of this ocular tolerance. ACAID was induced in BALB/c mice by an intracameral injection of 50mug ovalbumin (OVA). The IDO expression in the splenocytes during ACAID was determined by fluorescent quantitative real-time PCR, Western blot analysis and immunohistochemistry. The development of ACAID was evaluated by the delayed-type hypersensitivity (DTH) response after intraperitoneal injection of an IDO inhibitor 1-methyl-dl-tryptophan (1-MT). Secretion of IFN-gamma and IL-4 by splenocytes and lymph node cells from the mice treated with or without 1-MT were also evaluated using intracellular cytokine staining. Our results showed that the IDO expression was significantly increased at both mRNA and protein levels following OVA intracameral injection. Inhibition of IDO with 1-MT prevented the development of ACAID, which was indicated by the re-appearance of the OVA-specific DTH response. IL-4 was significantly reduced and IFN-gamma was partially recovered after the treatment of 1-MT. Our study reveal that IDO is up-regulated during ACAID and IDO inhibitor prevents ACAID generation, suggesting that IDO is involved in the development of this immune tolerance.

Essential role for hematopoietic prostaglandin D2 synthase in the control of delayed type hypersensitivity.

Hematopoietic prostaglandin D(2) synthase (hPGD(2)S) metabolizes cyclooxygenase-derived prostaglandin (PG) H(2) to PGD(2), which is dehydrated to cyclopentenone PGs, including 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)). PGD(2) acts through two receptors (DP1 and DP2/CRTH2), whereas 15d-PGJ(2) can activate peroxisome proliferator-activated receptors or inhibit a range of proinflammatory signaling pathways, including NF-kappaB. Despite eliciting asthmatic and allergic reactions through the generation of PGD(2), it is not known what role hPGD(2)S plays in T helper (Th)1-driven adaptive immunity. To investigate this question, the severity and duration of a delayed type hypersensitivity reaction was examined in hPGD(2)S knockout and transgenic mice. Compared with their respective controls, knockouts displayed a more severe inflammatory response that failed to resolve, characterized histologically as persistent acute inflammation, whereas transgenic mice had little detectable inflammation. Lymphocytes isolated from inguinal lymph nodes of hPGD(2)S(-/-) animals showed hyperproliferation and increased IL-2 synthesis effects that were rescued by 15d-PGJ(2), but not PGD(2), working through either of its receptors. Crucially, 15d-PGJ(2) exerted its suppressive effects through the inhibition of NF-kappaB activation and not through peroxisome proliferator-activated receptor signaling. In contrast, lymph node cultures from transgenics proliferated more slowly and synthesized significantly less IL-2 than controls. Therefore, contrary to its role in driving Th2-like responses, this report shows that hPGD(2)S may act as an internal braking signal essential for bringing about the resolution of Th1-driven delayed type hypersensitivity reactions. Consequently, hPGD(2)S-derived cyclopentenone PGs may protect against inflammatory diseases, where T lymphocytes play a pathogenic role, as in rheumatoid arthritis, atopic eczema, and chronic rejection.

Role of endothelial heparanase in delayed-type hypersensitivity.

Heparanase is an endoglycosidase that cleaves heparan sulfate (HS), the main polysaccharide of the basement membrane (BM). HS is responsible for BM integrity and barrier function. Hence, enzymatic degradation of HS in the vascular subendothelial BM is a prerequisite for extravasation of immune cells and plasma components during inflammation. Here, we demonstrate a highly coordinated local heparanase induction upon elicitation of delayed-type hypersensitivity (DTH) reaction in the mouse ear. By monitoring in vivo activation of luciferase gene driven by the heparanase promoter, we demonstrate activation of heparanase transcription at an early stage of DTH. We report that heparanase is produced locally by the endothelium at the site of DTH-associated inflammation. Key DTH mediators, tumor necrosis factor-alpha and interferon-gamma, were found to induce heparanase in cultured endothelial cells. Endothelium emerges as an essential cellular source of heparanase enzymatic activity that, in turn, allows for remodeling of the vascular BM, increased vessel permeability, and extravasation of leukocytes and plasma proteins. In vivo administration of antiheparanase siRNA or an inhibitor of heparanase enzymatic activity effectively halted DTH inflammatory response. Collectively, our results highlight the decisive role of endothelial heparanase in DTH inflammation and its potential as a promising target for anti-inflammatory drug development.

Histamine intolerance-like symptoms in healthy volunteers after oral provocation with liquid histamine.

Histamine in food at non-toxic doses has been proposed to be a major cause of food intolerance causing symptoms like diarrhea, hypotension, headache, pruritus and flush ("histamine intolerance"). Histamine-rich foods such as cheese, sausages, sauerkraut, tuna, tomatoes, and alcoholic beverages may contain histamine up to 500 mg/kg. We conducted a randomized, double-blind, placebo-controlled cross-over study in 10 healthy females (age range 22-36 years, mean 29.1 +/- 5.4) who were hospitalized and challenged on two consecutive days with placebo (peppermint tea) or 75 mg of pure histamine (equaling 124 mg histamine dihydrochloride, dissolved in peppermint tea). Objective parameters (heart rate, blood pressure, skin temperature, peak flow) as well as a total clinical symptom score using a standardized protocol were recorded at baseline, 10, 20, 40, 80 minutes, and 24 hours. The subjects received a histamine-free diet also low in allergen 24 hours before hospitalization and over the whole observation period. Blood samples were drawn at baseline, 10, 20, 40, and 80 minutes, and histamine and the histamine-degrading enzyme diamine oxidase (DAO) were determined. After histamine challenge, 5 of 10 subjects showed no reaction. One individual experienced tachycardia, mild hypotension after 20 minutes, sneezing, itching of the nose, and rhinorrhea after 60 minutes. Four subjects experienced delayed symptoms like diarrhea (4x), flatulence (3x), headache (3x), pruritus (2x) and ocular symptoms (1x) starting 3 to 24 hours after provocation. No subject reacted to placebo. No changes were observed in histamine and DAO levels within the first 80 minutes in non-reactors as well as reactors. There was no difference in challenge with histamine versus challenge with placebo. We conclude that 75 mg of pure liquid oral histamine--a dose found in normal meals--can provoke immediate as well as delayed symptoms in 50% of healthy females without a history of food intolerance.

Early delayed-type hypersensitivity eosinophil infiltrates depend on T helper 2 cytokines and interferon-gamma via CXCR3 chemokines.

We investigated the role of T helper (Th)1- and Th2-type cytokines in delayed-type hypersensitivity to soluble protein antigens elicited early postimmunization. Mice were sensitized by intradermal injection without adjuvants, or subcutaneously with complete Freund's adjuvant, and subsequently ear challenged intradermally. As soon as day 3, antigen-specific eosinophil-rich responses were elicited in wild-type mice, but not in T-cell receptor-alpha-/- mice without adjuvant. Draining lymph node T cells stimulated with antigen secreted interleukin (IL)-4, IL-5 and interferon-gamma (IFN-gamma). IFN-gamma-dependent specific immunoglobulin G (IgG)2a and IL-4-dependent IgG1 were also generated. Delayed-type hypersensitivity ear swelling and local eosinophil recruitment were decreased in IL-5-/-, IL-4-/- and signal transducer and activator of transcription-6 (STAT-6)-/- mice, and with anti-IL-4 treatment of wild-type mice, suggesting Th2 mechanisms. Interestingly, responses were also decreased in IFN-gamma-/- mice, and IFN-gamma protein and the IFN-gamma-inducible CXC chemokine, IP-10, were present in 24-hr ear tissue extracts, suggesting Th1 effects. Finally, ear swelling, total histology and eosinophils were decreased in mice deficient in CXCR3, the chemokine receptor for IP-10. These results suggest that both a Th2-like (IL-5, IL-4 and STAT-6) and a Th1-like (IFN-gamma, IP-10, CXCR3) pathway contribute to eosinophil recruitment in early delayed-type hypersensitivity.

Significant accumulations of cathepsin B and prolylendopeptidase in inflammatory focus of delayed-type hypersensitivity induced by Mycobacterium tuberculosis in mice.

To clarify what kinds of proteinases are secreted into the foci of allergic-inflammation involving delayed-type hypersensitivity reaction, we examined the characteristic releases of various proteinases into the foci of Mycobacterium tuberculosis (M. tuber.)-induced delayed-type allergic-inflammation in mice. The significant activities of cathepsin B and prolylendopeptidase were observed in the washing-fluids of subcutaneous inflammatory foci of M. tuber.-induced delayed-type allergic-inflammation, but not M. tuber.-induced acute-inflammation. The SDS-resistant complex of cathepsin B and a protein substrate with apparent molecular mass of 74 kDa was observed by Western blot analysis. On the other hand, no significant accumulations of other proteinases, such as matrix metalloproteinases, cathepsin D, and serine proteinases, were determined. CA-074, a specific inhibitor of cathepsin B, suppressed both swelling and cathepsin B activity in the footpad having M. tuber.-induced delayed-type allergic-inflammation in vivo. These results suggest that cathepsin B may play an important role in the formation of M. tuber.-induced delayed-type allergic-inflammation.

Blunted stress responses in delayed type hypersensitivity in mice lacking the neuronal isoform of nitric oxide synthase.

Nitric oxide (NO) is implicated in inflammation and hypothalamic-pituitary responses to immune stimuli; however, the specific role of NO from neurons during stress-induced immune responses remains unspecified. We measured antigen-specific delayed-type-hypersensitivity (DTH) responses in the skin of wild-type (WT) and neuronal nitric oxide synthase knockout (nNOS(-/-)) mice at baseline and after 2 h of restraint. Baseline corticosterone concentrations were higher in nNOS(-/-) than WT mice. However, stress-induced increases in corticosterone were dampened in nNOS(-/-) mice, and restraint suppressed DTH only in WT animals. Furthermore, WT mice lost more body mass after stress, and exhibited more anxiety-like behavior in the open field, than nNOS(-/-) mice. Neuronal NO appears to be involved in the neuroendocrine-immune response to stress, perhaps via glucocorticoid regulation.

Cu/Zn superoxide dismutase plays important role in immune response.

Activation of macrophages leads to the secretion of cytokines and enzymes that shape the inflammatory response and increase metabolic processes. This, in turn, results in increased production of reactive oxygen species. The role of Cu/Zn superoxide dismutase (SOD-1), an important enzyme in cellular oxygen metabolism, was examined in activated peritoneal elicited macrophages (PEM) and in several inflammatory processes in vivo. LPS and TNF-alpha induced SOD-1 in PEM. SOD-1 induction by LPS was mainly via extracellular signal-regulated kinase-1 activation. Transgenic mice overexpressing SOD-1 demonstrated a significant increase in the release of TNF-alpha and of the metalloproteinases MMP-2 and MMP-9 from PEM. Disulfiram (DSF), an inhibitor of SOD-1, strongly inhibited the release of TNF-alpha, vascular endothelial growth factor, and MMP-2 and MMP-9 from cultured activated PEM. These effects were prevented by addition of antioxidants, further indicating involvement of reactive oxygen species. In vivo, transgenic mice overexpressing SOD-1 demonstrated a 4-fold increase in serum TNF-alpha levels and 2-fold stronger delayed-type hypersensitivity reaction as compared with control nontransgenic mice. Conversely, oral administration of DSF lowered TNF-alpha serum level by 4-fold, lowered the delayed-type hypersensitivity response in a dose-dependent manner, and significantly inhibited adjuvant arthritis in Lewis rats. The data suggest an important role for SOD-1 in inflammation, establish DSF as a potential inhibitor of inflammation, and raise the possibility that regulation of SOD-1 activity may be important in the treatment of immune-dependent pathologies.

A novel role of alkaline phosphatase in protection from immunological liver injury in mice.

AIMS/BACKGROUND: Little is known about the role of alkaline phosphatase (AP) in liver diseases, except for its elevation in jaundice or cholestasis. Its substrate, endotoxin, is usually elevated in patients as well as animals with liver damage. This study aimed to provide evidence for its new role as protection against immunological liver damage. METHODS: Liver injury was induced in mice by delayed-type hypersensitivity to picryl chloride. AP activity was measured using a commercial kit. RESULTS: In acute liver injury, a significant decrease in AP activity in serum was observed but there was an increase in liver tissue. Single administration of cyclophosphamide before sensitization with picryl chloride exacerbated the liver injury, with more serious AP changes, while consecutive use after the sensitization alleviated the injury with a recovery from the changes. When liver injury proceeded for 1 week, both serum and liver showed decreased AP activity. Lipopolysaccharide facilitated alanine transaminase release from levamisole-pretreated but not non-treated hepatocytes from naive mice. However, the release was confirmed from liver slices of mice with liver injury proceeding for 1 week, even without levamisole pretreatment. CONCLUSION: The development of liver injury may lead to a dysfunction in AP synthesis and release. Levamisole may make normal hepatocytes, like the hepatocytes from liver-injured mice, highly sensitive to lipopolysaccharide through inhibiting AP synthesis. The findings obtained in this study suggest that AP may contribute to protection from injury by a mechanism involving neutralization of endotoxin.

Nonhematopoietic expression of Janus kinase 3 is required for efficient recruitment of Th2 lymphocytes and eosinophils in OVA-induced airway inflammation.

Tyrosine kinases of the Janus kinase (Jak) family transduce signals from the type I and type II cytokine receptors. Jak3 is unique in this family because its expression must be induced and is predominantly limited to cells of the lymphoid and myeloid lineages. Deficient expression of Jak3 interferes with normal development and function of T, B, and NK cells. Using irradiated Jak3-deficient (Jak3-/-) mice reconstituted with normal bone marrow (Jak3-/-chimeric mice), we have investigated possible actions of Jak3 outside of the hematopoietic system. We show that efficient recruitment of inflammatory cells to the airways of OVA-sensitized mice challenged with aerosolized OVA requires the expression of Jak3 in radioresistant nonhematopoietic cells. Failure to develop eosinophil-predominant airway inflammation in Jak3-/- chimeric mice is not due to failure of T cell sensitization, because Jak3-/- chimeric mice showed delayed-type hypersensitivity responses indistinguishable from wild-type chimeric mice. Jak3-/- chimeric mice, however, express less endothelial-associated VCAM-1 after airway Ag challenge. Given the key role of VCAM-1 in recruitment of Th2 cells and eosinophils, our data suggest that Jak3 in airway-associated endothelial cells is required for the expression of eosinophilic airway inflammation. This requirement for nonhematopoietic expression of Jak3 represents the first demonstration of a physiological function of Jak3 outside of the lymphoid lineages.

[Effect of the cholinesterase reactivator dipyroxime in various models of delayed hypersensitivity during acute intoxication by acrylonitrile]. / Vliianie reaktivatora kholinésterazy dipiroksima na formirovanie giperchuvstvitel'nosti zamedlennogo tipa.

Delayed type hypersensitivity (DTH) response with respect to sheep erythrocytes was studied on various models in CBA mice against the background of acute intoxication with nitrile acrylic acid (NAA). The effect of dipiroxime on the DTH response under these conditions was determined and the relationship of these reactions with the activity of alpha-naphthylbutyratesterase in splenic cells and popliteal lymph nodes was assessed. Dipiroxime partly recovered DTH in various experimental series (except for the reaction of suppressor cell transfer) by restoring the alpha-naphthylbutyratesterase activity in cells of the lymphoid organs studied.

Heme oxygenase isoform expression in cellular and antibody-mediated models of acute inflammation in the rat.

Heme oxygenase (HO) is the rate-limiting enzyme in the catabolism of heme to biliverdin, carbon monoxide (CO), and free iron. The enzyme exists as a constitutive isoform (HO-2) and an inducible isoform (HO-1), which is also a stress protein (HSP32). HO-1 has previously been shown to be associated with the resolution phase of a non-immune model of acute inflammation. In addition, elevation of the enzyme was markedly anti-inflammatory. In the present study, these observations have been extended to two pleural models of immune-driven inflammation in the rat, an immediate type III hypersensitivity (Arthus) reaction and a delayed type IV hypersensitivity reaction. Whilst these models have differing inflammatory mechanisms and time courses, they both showed HO activity to be maximal during the resolution phase. This activity was associated with increases in exudate bilirubin (a breakdown product of biliverdin) and increased expression of HO-1. Immunocytochemical analysis of inflammatory cell smears from the two models showed that HO-1 and HO-2 expression was restricted to mononuclear cells in the type IV hypersensitivity reaction, but included the polymorphonuclear cell population in the type III hypersensitivity reaction. Thus, irrespective of the pathogenesis of the lesion, evidence is accumulating to suggest that HO-1 has a universal role in the resolution of inflammation.

Alpha(1,3)-fucosyltransferase VII and alpha(2,3)-sialyltransferase IV are up-regulated in activated CD4 T cells and maintained after their differentiation into Th1 and migration into inflammatory sites.

Activated Th1 CD4 T cells bind to P-selectin and migrate into inflamed tissue, whereas Th2 cells do not. We show that alpha(1, 3)-fucosyltransferase VII (FucT-VII) and alpha(2, 3)-sialyltransferase IV (ST3GalIV), which are crucial for the biosynthesis of functional P-selectin ligands, are absent in naive CD4 T cells, but are rapidly up-regulated upon activation. Th1 or Th2 differentiation in the presence of polarizing cytokines leads to down-regulation of FucT-VII mRNA selectively in Th2 but not in Th1 cells. Influencing the differentiation by varying the priming dose of antigenic peptide results in similar FucT-VII down-regulation only in Ag-specific Th2 cells. ST3GalIV levels remain elevated. FucT-VII and ST3GalIV mRNAs are also up-regulated by Th1 cells primed in vivo and recruited into the lymph nodes draining delayed-type hypersensitivity sites. We identify FucT-VII gene expression as a principal difference between Th1 and Th2 cells, and underscore the importance of FucT-VII and ST3GalIV expression for the biosynthesis of functional selectin ligands.

[Matrix metalloproteinases. Potential targets for new treatments in inflammatory demyelinating diseases of the nervous system]. / Matrix-Metalloproteinasen. Mögliche Ansatzpunkte neuer Therapien bei entzündlich demyelinisierenden Erkrankungen des Nervensystems.

Inflammatory demyelinating diseases of the nervous system, such as multiple sclerosis or the Guillain-Barré syndrome represent severely disabling disorders, often seen by the neurologist, with still only limited means for therapeutical intervention. The underlying pathomechanisms remain in large part elusive, however mounting evidence suggests that enzymes of the family of matrix metalloproteinases are of relevance in the pathogenesis of these disorders. Experimental in vivo data as well as results from other medical fields emphasize that the selective inhibition of these proteases could be a promising therapeutical approach. The following review summarizes the role of matrix metalloproteinases in inflammatory demyelinating diseases of the central as well as peripheral nervous system and discusses the therapeutical application of synthetic inhibitors in these disorders.