Inhibitory Effects of Chlorella Extract on Airway Hyperresponsiveness and Airway Remodeling in a Murine Model of Asthma

Chlorella extract （CE） has been shown to induce production of T helper-1 cytokines, and regulate serum IgE levels in animal models of asthma. We aimed to evaluate whether CE could inhibit ovalbumin （OVA）-induced airway hyperresponsiveness （AHR） and airway remodeling in a murine model of asthma. Balb/c mice were allocated to four groups: a control group （no OVA exposure, not given CE）, a CE group （no OVA exposure, given CE）, an asthma group （sensitized/challenged with OVA, not given CE） and a CE＋asthma group （sensitized/challenged with OVA, given CE）. In the asthma and CE＋asthma groups, mice were sensitized with OVA on day 0 and day 12, and then challenged with OVA on three consecutive days. In the CE and CE＋asthma groups, the mice were given feed containing 2％ CE. We assessed AHR to methacholine, and analyzed bronchoalveolar lavage fluid （BALF）, serum, lung tissue and spleen cells. Administration of CE was associated with significantly lower AHR in OVA-sensitized and challenged mice. CE administration was also associated with marked reduction of total cells, eosinophils and T helper-2 cytokines （IL-4, IL-5 and IL-13） in BALF. In addition, administration of CE significantly decreased the numbers of periodic acid-Schiff （PAS）-positive cells in OVA-sensitized and challenged mice. Administration of CE also directly suppressed IL-4, IL-5 and IL-13 production in spleen cells of OVA-sensitized and challenged mice. These results indicate that CE can partly prevent AHR and airway remodeling in a murine model of asthma

Type II Natural Killer T Cells that Recognize Sterol Carrier Protein 2 Are Implicated in Vascular Inflammation in the Rat Model of Systemic Connective Tissue Diseases

We previously generated a rat model that developed systemic connective tissue diseases, including synovitis, myositis, and small-vessel vasculitis (SVV), and established a vascular endothelial cell–reactive T-cell clone, VASC-1, from the model. VASC-1 was determined to be a type II natural killer T-cell clone. In this study, we attempted to identify the antigen recognized by VASC-1. The monkey-derived cell line COS-7 was used because VASC-1 does not bind naturally to COS-7, although the amino acid sequences are well conserved between monkey CD1d and rat CD1d. We generated 98 COS-7 clones transfected with miscellaneous rat cDNA and screened them for VASC-1 binding. Consequently, we found one clone, 4D2, which could bind to VASC-1. Sequencing identified the rat cDNA introduced into 4D2 as sterol carrier protein 2 (SCP2). When VASC-1 was co-cultured with SCP2 knockdown rat vascular endothelial cells, VASC-1 binding was reduced significantly. Moreover, we designed a series of rat SCP2 peptides and introduced them into COS-7 cells. On the basis of VASC-1 binding and proliferation, we revealed that the peptide rSCP2518-532 included the epitope recognized by VASC-1. Furthermore, immunization with rSCP2518-532 accelerated the development of SVV in the rat model. The collective findings suggest that type II natural killer T cells reactive with autologous SCP2 are implicated in vascular inflammation in the rat model

Lipid Profile of Activated Macrophages and Contribution of Group V Phospholipase A2

Macrophages activated by Interleukin (IL)-4 (M2) or LPS+ Interferon (IFN)γ (M1) perform specific functions respectively in type 2 inflammation and killing of pathogens. Group V phospholipase A2 (Pla2g5) is required for the development and functions of IL-4-activated macrophages and phagocytosis of pathogens. Pla2g5-generated bioactive lipids, including lysophospholipids (LysoPLs), fatty acids (FAs), and eicosanoids, have a role in many diseases. However, little is known about their production by differentially activated macrophages. We performed an unbiased mass-spectrometry analysis of phospholipids (PLs), LysoPLs, FAs, and eicosanoids produced by Wild Type (WT) and Pla2g5-null IL-4-activated bone marrow-derived macrophages (IL-4)BM-Macs (M2) and (LPS+IFNγ)BM-Macs (M1). Phosphatidylcholine (PC) was preferentially metabolized in (LPS+IFNγ)BM-Macs and Phosphatidylethanolamine (PE) in (IL-4)BM-Macs, with Pla2g5 contributing mostly to metabolization of selected PE molecules. While Pla2g5 produced palmitic acid (PA) in (LPS+IFNγ)BM-Macs, the absence of Pla2g5 increased myristic acid (MA) in (IL-4)BM-Macs. Among eicosanoids, Prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2) were significantly reduced in (IL-4)BM-Macs and (LPS+IFNγ)BM-Macs lacking Pla2g5. Instead, the IL-4-induced increase in 20-carboxy arachidonic acid (20CooH AA) was dependent on Pla2g5, as was the production of 12-hydroxy-heptadecatrienoic acid (12-HHTrE) in (LPS+IFNγ)BM-Macs. Thus, Pla2g5 contributes to PE metabolization, PGE2 and PGD2 production independently of the type of activation, while in (IL-4)BM-Macs, Pla2g5 regulates selective lipid pathways and likely novel functions

Anti-IgE therapy for allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is a severe type of asthma. Some cases are resistant to treatment, even with regular use of antiasthmatic drugs and antifungal agents. The diagnosis of ABPA was made in a 40-year-old patient with ABPA according to the Rosenberg-Patterson criteria. Symptoms were not controlled despite regular use of antiasthmatic drugs, daily systemic steroids, and antifungal agents. Omalizumab, administered in an attempt to stabilize these uncontrolled symptoms, was effective with no adverse events. Our experience suggests omalizumab is a potential candidate drug for controlling steroid-dependent ABPA

Macrophages regulate lung ILC2 activation via Pla2g5-dependent mechanisms

Group V phospholipase A2 (Pla2g5) is a lipid-generating enzyme necessary for macrophage effector functions in pulmonary inflammation. However, the lipid mediators involved and their cellular targets have not been identified. Mice lacking Pla2g5 showed markedly reduced lung ILC2 activation and eosinophilia following repetitive Alternaria Alternata inhalation. While Pla2g5-null mice had Wt levels of immediate IL-33 release after one Alternaria dose, they failed to upregulate IL-33 in macrophages following repeated Alternaria administration. Unexpectedly, while adoptive transfer of bone marrow-derived (BM)-macrophages restored ILC2 activation and eosinophilia in Alternaria-exposed Pla2g5-null mice, exogenous IL-33 did not. Conversely, transfers of Pla2g5-null BM-macrophages reduced inflammation in Alternaria-exposed Wt mice. Mass spectrometry analysis of free fatty acids (FFAs) demonstrated significantly reduced FFAs (including linoleic acid (LA) and oleic acid (OA)) in lung and BM-macrophages lacking Pla2g5. Exogenous administration of LA or LA+OA to Wt mice sharply potentiated IL-33-induced lung eosinophilia and ILC2 expansion in-vitro and in-vivo. In contrast, OA potentiated IL-33-induced inflammation and ILC2 expansion in Pla2g5-null mice, but LA was inactive both in-vivo and in-vitro. Notably, Pla2g5-null ILC2s showed significantly reduced expression of the FFA-receptor-1 compared to Wt ILC2s. Thus, macrophage-associated Pla2g5 contributes significantly to type-2 immunity through regulation of IL-33 induction and FFA-driven ILC2 activation