Macrophage migration inhibitory factor-mediated mast cell extracellular traps induce inflammatory responses upon Fusobacterium nucleatum infection.

Mast cell extracellular traps (MCETs) released by mast cells contribute to host defense. In this study, we investigated the effects of MCETs released from mast cells after infection with a periodontal pathogen Fusobacterium nucleatum. We found that F. nucleatum induced MCET release from mast cells, and that MCETs expressed macrophage migration inhibitory factor (MIF). Notably, MIF bound to MCETs induced proinflammatory cytokine production by monocytic cells. These findings suggest that MIF expressed on MCETs, released from mast cells upon infection with F. nucleatum, promotes inflammatory responses that may be associated with the pathogenesis of periodontal disease.

Hericium erinaceus ethanol extract and ergosterol exert anti-inflammatory activities by neutralizing lipopolysaccharide-induced pro-inflammatory cytokine production in human monocytes.

Edible mushrooms are known to exert anti-inflammatory effects. In this study, the effects of ethanol extracts from edible mushrooms, such as Hericium erinaceus, and other edible mushrooms on inflammatory responses were investigated. Experiments were conducted using the inflammatory responses of human monocytes induced by lipopolysaccharide (LPS), a bacterial component, that provokes inflammation. Notably, we demonstrated that LPS mixed with ethanol and hot water extracts derived from edible mushrooms attenuated the production of inflammatory cytokines, such as interleukin (IL)-1ß, -6, and -8, induced by LPS in human monocytic cell cultures. Moreover, we found that the ethanol extract of H. erinaceus contained ergosterol, which attenuated IL-8 production in LPS-stimulated cells. Subsequent component analysis of the ethanol extract of H. erinaceus revealed that ergosterol binds to lipid A to attenuate LPS-induced inflammation. Together, our findings suggest that ergosterol in ethanol extracts from edible mushrooms can prevent the induction of inflammation by binding to LPS.

Structural modification of Escherichia coli lipid A by myristoyltransferase gene from Klebsiella pneumoniae.

Lipid A in lipopolysaccharide (LPS) of Escherichia coli mutant strains was modified by the introduction of myristoyltransferase gene cloned from Klebsiella pneumoniae. When the gene was introduced into the mutant having lipid A containing only 3-hydroxymyristic acids, it produced lipid A with two additional myristic acids (C14:0 ). When the same gene was introduced into the mutant with pentaacylated lipid A containing one lauric acid (C12:0 ), C12:0 was replaced by C14:0 . IL-6-inducing activity of LPS with modified lipid A structure suggested that C12:0 in lipid A could be replaced by C14:0 without changing the immunostimulating activity.

Modification of lipid A structure and activity by the introduction of palmitoyltransferase gene to the acyltransferase-knockout mutant of Escherichia coli.

Lauroyltransferase gene (lpxL), Myristoyltransferase gene (lpxM) and palmitoyltransferase gene (crcA) of Escherichia coli BL21 were independently disrupted by the insertional mutations. The knockout mutant of two transferase genes (lpxL and crcA) produced lipid A with no lauric or palmitic acids and only a little amount of myristic acid. The mutant was susceptible to polymyxin B, but showed comparable growth with the wild-type strain at 30°C. The palmitoyltransferase gene from E. coli (crcA) or Salmonella (pagP) was amplified by PCR, cloned in pUC119, and transferred into the double-knockout mutant by transformation. The transformant contained palmitic acid in the lipid A, and recovered resistance to polymyxin B. Mass spectrometric analysis revealed that palmitic acid was linked to the hydroxyl group of 3-hydroxymyristic acid at C-2 position of proximal (reducing-end) glucosamine. LPS from the double-knockout mutant showed reduced IL-6-inducing activity to macrophage-like line cells compared to that of the wild-type strain, and the activity was only slightly restored by the introduction of palmitic acid to the lipid A. These results suggested that the introduction of one palmitic acid was enough to recover the integrity of the outer membrane, but not enough for the stimulation of macrophages.

CD40 ligand gene and Kawasaki disease.

Kawasaki disease (KD) is an acute systemic vasculitis syndrome of infants and young children. Although its etiology is largely unknown, epidemiological findings suggest that genetic factors play a role in the pathogenesis of KD. To identify genetic factors, affected sib-pair analysis has been performed. One of the identified peaks was located on the Xq26 region. A recent report of elevated expression of CD40 ligand (CD40L), which maps to Xq26, during the acute-phase KD, and its relationship to the development of coronary artery lesions (CAL) prompted us to screen for polymorphism of CD40L and to study the association of the gene to KD. A newly identified SNP in intron 4 (IVS4+121 A>G) is marginally over-represented in KD patients as compared to controls (109/602, 18.1 vs 111/737, 15.1%). When male KD patients with CAL were analyzed as a patient group, the SNP was significantly more frequent than in controls (15/58, 25.9%, vs 111/737, 15.1%, OR=2.0, 95% CI=1.07-3.66; P=0.030). Interestingly, this variation was extremely rare in a control Caucasian population (1/145, 0.7%). Our results suggest a role of CD40L in the pathogenesis of CAL and might explain the excess of males affected with KD.

Novel tryptamine-related substances, 5-sulphatoxydiacetyltryptamine, 5-hydroxydiacetyltryptamine, and reduced melatonin in human urine and the determination of those compounds, 6-sulphatoxymelatonin, and melatonin with fluorometric HPLC.

During our studies to establish a method for identifying tryptamine-related substances in human urine, we detected three large peaks of unknown origin in an HPLC chromatogram. Fluorometric HPLC and HPLC-TOF-MS/MS analyses led to the identification of these substances as 6-sulphatoxymelatonin, 5-sulphatoxydiacetyltryptamine, and reduced melatonin. This is the first report of the latter two compounds in human urine. Here, we report the results of two fluorometric HPLC assays of these three substances, as well as melatonin, 6-hydroxymelatonin, and 5-hydroxydiacetyltryptamine, using synthesized standards and discuss the possibility that 5-hydroxydiacetyltryptamine (the parent substance of 5-sulphatoxydiacetyltryptamine) and reduced melatonin have radical scavenging activity.

Serum antibodies of periodontitis patients compared to the lipopolysaccharides of Porphyromonas gingivalis and Fusobacterium nucleatum.

Serum antibody titers against the lipopolysaccharides (LPSs) of Porphyromonas gingivalis and Fusobacterium nucleatum were compared between 9 periodontitis patients and 24 healthy persons. The IgG titers against the LPSs of P. gingivalis ATCC 33277(T) and W50 were clearly higher in the patients than in the healthy persons. However, IgM titers against the LPSs of P. gingivalis strains were relatively low, and no significant difference was observed between the patients and healthy persons. On the other hand, IgG and IgM titers against the LPS of Fusobacterium nucleatum JCM 8532(T) in some patients were significantly higher than those in the healthy persons, although the difference in IgG titers was not large compared to that of the LPS of P. gingivalis. These results suggest that the antibody measurement of patients' sera against the LPS of periodontal bacteria can be applied for the diagnosis of periodontitis.