Pasquale Maffia

Phytochemical compounds involved in the anti-inflammatory effect of propolis extract

Two ethanolic propolis extracts (EPE) with and without the caffeic acid phenethyl ester (CAPE), CAPE and galangin (major components of propolis) were investigated for anti-inflammatory activity in rats using carrageenin foot oedema, carrageenin pleurisy and adjuvant arthritis. In our experiments, EPE with CAPE and CAPE alone significantly inhibited carrageenin oedema, carrageenin pleurisy and adjuvant arthritis. In contrast EPE without CAPE and galangin did not exhibit anti-inflammatory effects in acute and chronic inflammation. These results suggest that the anti-inflammatory activity of propolis is due to CAPE.

Hydrogen sulfide as a mediator of human corpus cavernosum smooth-muscle relaxation

Hydrogen sulfide (H2S) is synthesized by 2 enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). l-Cysteine (l-Cys) acts as a natural substrate for the synthesis of H2S. Human penile tissue possesses both CBS and CSE, and tissue homogenates efficiently convert l-Cys to H2S. CBS and CSE are localized in the muscular trabeculae and the smooth-muscle component of the penile artery, whereas CSE but not CBS is also expressed in peripheral nerves. Exogenous H2S [sodium hydrogen sulfide (NaHS)] or l-Cys causes a concentration-dependent relaxation of strips of human corpus cavernosum. l-Cys relaxation is inhibited by the CBS inhibitor, aminoxyacetic acid (AOAA). Electrical field stimulation of human penile tissue, under resting conditions, causes an increase in tension that is significantly potentiated by either propargylglycine (PAG; CSE inhibitor) or AOAA. In rats, NaHS and l-Cys promote penile erection, and the response to l-Cys is blocked by PAG. Our data demonstrate that the l-Cys/H2S pathway mediates human corpus cavernosum smooth-muscle relaxation.

The endocannabinoid system and the molecular basis of paralytic ileus in mice

The endocannabinoid system (i.e., the cannabinoid receptors and their endogenous ligands) plays an important role in the physiological control of intestinal motility. However, its participation in intestinal pathological states is still poorly understood. In the present study, we investigated the possible role of the endocannabinoid system in the pathogenesis of paralytic ileus, a pathological state consisting of decreased intestinal motility following peritonitis, surgery, or other noxious situations. Ileus was induced by i.p. administration of acetic acid, and gastrointestinal propulsion was assessed by the charcoal method. Endocannabinoid levels were measured by isotope‐dilution gas chromatography‐mass spectrometry, whereas cannabinoid CB1 receptors were identified by immunohistochemistry. Acetic acid administration inhibited gastrointestinal transit (ileus), and this effect was accompanied by increased levels of the endocannabinoid anandamide compared with control mice and by overexpression of CB1 receptors in myenteric nerves. Furthermore, acetic acid‐induced ileus was alleviated by the CB1 receptor antagonist SR141716A and worsened by VDM11, a selective inhibitor of anandamide cellular uptake (and hence inactivation). From these findings, it can be concluded that the intestinal hypomotility typical of paralytic ileus is due, at least in part, to the enhancement of anandamide levels and CB1 expression during this condition, and that selective, nonpsychotropic CB1 receptor antagonists could represent new drugs to treat this disorder.

Plasmacytoid Dendritic Cells Play a Key Role in Promoting Atherosclerosis in Apolipoprotein E–Deficient Mice

Objective—Clinical studies have identified that reduced numbers of circulating plasmacytoid dendritic cells (pDCs) act as a predictor of cardiovascular events in coronary artery disease and that pDCs are detectable in the shoulder region of human atherosclerotic plaques, where rupture is most likely to occur. Results from animal models are controversial, with pDCs seen to inhibit or promote lesion development depending on the experimental settings. Here, we investigated the role of pDCs in atherosclerosis in apolipoprotein E−deficient mice. Methods and Results—We demonstrated that the aorta and spleen of both apolipoprotein E−deficient and C57BL/6 mice displayed similar numbers of pDCs, with similar activation status. In contrast, assessment of antigen uptake/presentation using the E&agr;/Y-Ae system revealed that aortic pDCs in apolipoprotein E−deficient- mice were capable of presenting in vivo systemically administered antigen. Continuous treatment of apolipoprotein E−deficient mice with anti−mouse plasmacytoid dendritic cell antigen 1 (mPDCA-1) antibody caused specific depletion of pDCs in the aorta and spleen and significantly reduced atherosclerosis formation in the aortic sinus (by 46%; P<0.001). Depletion of pDCs also reduced macrophages (by 34%; P<0.05) and increased collagen content (by 41%; P<0.05) in aortic plaques, implying a more stable plaque phenotype. Additionally, pDC depletion reduced splenic T-cell activation and inhibited interleukin-12, chemokine (C-X-C motif) ligand 1, monokine induced by interferon-&ggr;, interferon &ggr;−induced protein 10, and vascular endothelium growth factor serum levels. Conclusion—These results identify a critical role for pDCs in atherosclerosis and suggest a potential role for pDC targeting in the control of the pathology.

Effect of a propolis extract and caffeic acid phenethyl ester on formation of aberrant crypt foci and tumors in the rat colon.

We have studied the effect of propolis and its main active ingredient caffeic acid phenetyl ester (CAPE) on formation of aberrant crypt foci (ACF) and tumors in the rat colon in vivo. CAPE (50 mg/kg i.p.) reduced the formation of ACF and tumor induced by azoxymethane, while propolis ethanolic extract was without effect. These results suggest a potential anti-carcinogenesis of CAPE but not propolis.

Artery tertiary lymphoid organs control aorta immunity and protect against atherosclerosis via vascular smooth muscle cell Lymphotoxin β receptors

Summary Tertiary lymphoid organs (TLOs) emerge during nonresolving peripheral inflammation, but their impact on disease progression remains unknown. We have found in aged Apoe−/− mice that artery TLOs (ATLOs) controlled highly territorialized aorta T cell responses. ATLOs promoted T cell recruitment, primed CD4+ T cells, generated CD4+, CD8+, T regulatory (Treg) effector and central memory cells, converted naive CD4+ T cells into induced Treg cells, and presented antigen by an unusual set of dendritic cells and B cells. Meanwhile, vascular smooth muscle cell lymphotoxin β receptors (VSMC-LTβRs) protected against atherosclerosis by maintaining structure, cellularity, and size of ATLOs though VSMC-LTβRs did not affect secondary lymphoid organs: Atherosclerosis was markedly exacerbated in Apoe−/−Ltbr−/− and to a similar extent in aged Apoe−/−Ltbrfl/flTagln-cre mice. These data support the conclusion that the immune system employs ATLOs to organize aorta T cell homeostasis during aging and that VSMC-LTβRs participate in atherosclerosis protection via ATLOs.

Glycolipids from sponges. IV. Immunomodulating glycosyl ceramides from the marine sponge agelas dispar.

The GSL composition of the marine sponge Agelas dispar was investigated. In addition to four GSLs previously isolated from Agelas clathrodes (2 and 4), Agelas conifera (3), and Agelas longissima (5), the novel triglycosylceramide 1a was isolated as a major component of the GSL mixture. All the isolated GSLs were tested using the MLR assay, and only some of them were shown to be immunoactivating agents, suggesting a possible structure-activity relationship.

Role of cyclopentenone prostaglandins in rat carrageenin pleurisy.

In this study, using rat carrageenin‐induced pleurisy, we found that treatment of rats with either indomethacin or NS‐398 suppressed the pleurisy at 2 h but significantly exacerbated this reaction at 48 h. Exacerbated inflammation was associated with reduced prostaglandin D2 levels, decreased heat shock factor 1 (HSF1) activation, reduced hsp72 expression and increased activation of nuclear factor κB (NF‐κB). Replacement of cyclopentenone prostaglandins by treating rats with either prostaglandin J2 or prostaglandin D2 reversed the exacerbating effects of cyclooxygenase inhibitors leading to the resolution of the reaction. In conclusion, we demonstrate that cyclopentenone prostaglandins may act as anti‐inflammatory mediators by inducing in inflammatory cells HSF1‐dependent hsp72 expression and NF‐κB inhibition, two crucial events for the remission of inflammation.

MHC Class II–Restricted Antigen Presentation by Plasmacytoid Dendritic Cells Drives Proatherogenic T Cell Immunity

Background— Plasmacytoid dendritic cells (pDCs) bridge innate and adaptive immune responses and are important regulators of immuno-inflammatory diseases. However, their role in atherosclerosis remains elusive. Methods and Results— Here, we used genetic approaches to investigate the role of pDCs in atherosclerosis. Selective pDC deficiency in vivo was achieved using CD11c-Cre × Tcf4–/flox bone marrow transplanted into Ldlr–/– mice. Compared with control Ldlr–/– chimeric mice, CD11c-Cre × Tcf4–/flox mice had reduced atherosclerosis levels. To begin to understand the mechanisms by which pDCs regulate atherosclerosis, we studied chimeric Ldlr–/– mice with selective MHCII deficiency on pDCs. Significantly, these mice also developed reduced atherosclerosis compared with controls without reductions in pDC numbers or changes in conventional DCs. MHCII-deficient pDCs showed defective stimulation of apolipoprotein B100–specific CD4+ T cells in response to native low-density lipoprotein, whereas production of interferon-&agr; was not affected. Finally, the atheroprotective effect of selective MHCII deficiency in pDCs was associated with significant reductions of proatherogenic T cell–derived interferon-&ggr; and lesional T cell infiltration, and was abrogated in CD4+ T cell–depleted animals. Conclusions— This study supports a proatherogenic role for pDCs in murine atherosclerosis and identifies a critical role for MHCII-restricted antigen presentation by pDCs in driving proatherogenic T cell immunity.

Inducing Experimental Arthritis and Breaking Self-Tolerance to Joint-Specific Antigens with Trackable, Ovalbumin-Specific T Cells

The importance of T cell Ag specificity and Th1 vs Th2 phenotype in synovial inflammation remains controversial. Using OVA-specific TCR transgenic T cells from DO11.10 mice, we demonstrate that mice receiving Th1, but not Th2, cells display a transient arthritis following immunization that is characterized by synovial hyperplasia, cellular infiltration, and cartilage erosion. OVA-specific T cells also accumulated in inflamed joints, suggesting that they could exert their inflammatory effect locally in the joint or in the draining lymph node. Importantly, this pathology was accompanied by a breakdown in self-tolerance, as evidenced by the induction of collagen-specific T and B cell responses. This model directly demonstrates a pivotal role for Th1 cells of an irrelevant specificity in the development of inflammatory arthritis. Furthermore, the ability to track these cells in vivo will make feasible studies revealing the dynamic role of T cells in arthritis.