Expression of toll-like receptor 2 and 4 is increased in the respiratory epithelial cells of chronic idiopathic interstitial pneumonia patients

SummaryBackgroundIdiopathic interstitial pneumonia (IIP) is characterized by chronic interstitial inflammation and fibrosis. Although mounting evidence has suggested that toll-like receptor (TLR) 2 and TLR4 are involved in the pathogenesis of non-infectious lung injury in vitro and in mouse models, their roles in human IIP remain unknown.MethodsTo address this issue, we investigated the expression patterns of TLR2 and TLR4 by immunohistochemistry in resected lung tissues from patients with usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP).ResultsType II pneumocytes, bronchial epithelial cells (BECs), and alveolar macrophages accounted for the majority of TLR2- and TLR4-expressing cells in both UIP and NSIP. The numbers of TLR2 and TLR4-positive respiratory epithelial (RE) cells, including type II pneumocytes and BECs, were significantly greater in UIP and NSIP than in the control. In particular, the numbers of TLR2-positive RE cells were much greater in UIP than in NSIP. The intensities of TLR2 and TLR4 expression in type II pneumocytes were also significantly stronger in UIP and NSIP than in the control. A comparison of the TLR expression patterns between the fibroblastic and fibrotic areas in UIP indicated that the numbers TLR2 and TLR4-positive RE cells were similar in fibroblastic areas, whereas the TLR2-positive RE cells outnumbered the TLR4-positive RE cells in the fibrotic areas.ConclusionsThis study demonstrates that RE cells over-express TLR2 and TLR4 in the lungs of IIP patients. These findings suggest that high expression of TLRs may contribute to the pathogenesis of human IIP

NKT cells promote antibody-induced joint inflammation by suppressing transforming growth factor β1 production

Although NKT cells has been known to exert protective roles in the development of autoimmune diseases, the functional roles of NKT cells in the downstream events of antibody-induced joint inflammation remain unknown. Thus, we explored the functional roles of NKT cells in antibody-induced arthritis using the K/BxN serum transfer model. NKT cell–deficient mice were resistant to the development of arthritis, and wild-type mice administrated with α-galactosyl ceramide, a potent NKT cell activator, aggravated arthritis. In CD1d−/− mice, transforming growth factor (TGF)-β1 was found to be elevated in joint tissues, and the blockade of TGF-β1 using neutralizing monoclonal antibodies restored arthritis. The administration of recombinant TGF-β1 into C57BL/6 mice reduced joint inflammation. Moreover, the adoptive transfer of NKT cells into CD1d−/− mice restored arthritis and reduced TGF-β1 production. In vitro assay demonstrated that interleukin (IL)-4 and interferon (IFN)-γ were involved in suppressing TGF-β1 production in joint cells. The adoptive transfer of NKT cells from IL-4−/− or IFN-γ−/− mice did not reverse arthritis and TGF-β1 production in CD1d−/− mice. In conclusion, NKT cells producing IL-4 and IFN-γ play a role in immune complex–induced joint inflammation by regulating TGF-β1

Colorectal Lymphoid Polyposis in a Child

Lymphoid polyposis is a lymphoid hyperplasia of the gastrointestinal tract that usually presents as multiple small polyps in the colon during childhood. This should be differentiated from other neoplastic or familial polyposis of the intestine. We report a case of benign lymphoid polyposis of the colon in a 17-month-old boy who presented with perianal fistula and mucosal ulceration. Colon study and rectal examinations showed multiple polyps in the sigmoid colon and rectum. Segmental resection of the sigmoid colon and rectum showed over 100 smallt 3 - 7 mrn) sessile or pedunculated polyps that were diffusely scattered through out the removed segment. The polyps consisted of mature lymphoid tissue with numerous germinal centers, that was located mostly in the lamina propria and submucosa

Notch controls the number of intraepithelial TCRαβ+CD8αα+ T cells

Intestinal intraepithelial lymphocytes (IELs) expressing CD8αα on αβ T cells (TCRαβ+CD8αα+ IELs) have suppressive capabilities in enterocolitis, but the mechanism that maintains homeostasis and cell number is not fully understood. Here, we demonstrated that the number of TCRαβ+CD8αα+ IELs was severely reduced in mice lacking recombination signal binding protein for immunoglobulin kappa J region (Rbpj) or Notch1 and Notch2 in T cells. Rbpj-deficient TCRαβ+CD8αα+ IELs expressed low levels of Atp8a2, which encodes a protein with flippase activity that regulates phospholipid asymmetry of plasma membrane such as flipping phosphatidylserine in the inner leaflet of plasma membrane. Rbpj-deficient TCRαβ+CD8αα+ IELs cannot maintain phosphatidylserine in the inner leaflet of the plasma membrane. Furthermore, depletion of intestinal macrophages restored TCRαβ+CD8αα+ IELs in Rbpj-deficient mice, suggesting that exposure of phosphatidylserine on the plasma membrane in Rbpj-deficient TCRαβ+CD8αα+ IELs acts as an “eat-me” signal. Together, these results revealed that Notch–Atp8a2 is a fundamental regulator for IELs and highlighted that membrane phospholipid asymmetry controlled by Notch-mediated flippase expression is a critical determinant in setting or balancing the number of TCRαβ+CD8αα+ IELs

成熟T細胞の生存はHOIPを介するシグナルに依存する

T cell development in the thymus is controlled by a multistep process. The NF-κB pathway regulates T cell development as well as T cell activation at multiple differentiation stages. The linear ubiquitin chain assembly complex (LUBAC) is composed of Sharpin, HOIL-1L and HOIP, and it is crucial for regulating the NF-κB and cell death pathways. However, little is known about the roles of LUBAC in T-cell development and activation. Here, we show that in T-HOIPΔlinear mice lacking the ubiquitin ligase activity of LUBAC, thymic CD4+ or CD8+ T cell numbers were markedly reduced with severe defects in NKT cell development. HOIPΔlinear CD4+ T cells failed to phosphorylate IκBα and JNK through T cell receptor-mediated stimulation. Mature CD4+ and CD8+ T cells in T-HOIPΔlinear mice underwent apoptosis more rapidly than control T cells, and it was accompanied by lower CD127 expression on CD4+CD24low and CD8+CD24low T cells in the thymus. The enforced expression of CD127 in T-HOIPΔlinear thymocytes rescued the development of mature CD8+ T cells. Collectively, our results showed that LUBAC ligase activity is key for the survival of mature T cells, and suggest multiple roles of the NF-κB and cell death pathways in activating or maintaining T cell-mediated adaptive immune responses

Mechanisms of Acquired Resistance to AZD9291 A Mutation-Selective, Irreversible EGFR Inhibitor

IntroductionAZD9291, a third-generation and mutation-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is active against patients with EGFRT790M-mutant non–small-cell lung cancer (NSCLC) who failed prior treatment with EGFR TKIs. However, acquired resistance to AZD9291 is inevitable. In this study, we identified the mechanisms of acquired resistance to AZD9291 in EGFRT790M-mutant NSCLC.MethodsFour NSCLC patients with both an EGFR exon 19 deletion and the EGFRT790M mutation after developing acquired resistance to first-generation EGFR TKIs received AZD9291 at doses of 20 to 80 mg/day in a phase I trial (NCT01802632). Paired tumor samples before and after treatment were obtained to evaluate EGFR modifications, alternative pathway activation, and histologic transformation. Genetic alterations were analyzed using Sanger sequencing, fluorescence in situ hybridization, real-time polymerase chain reaction, and targeted exome sequencing.ResultsAll four patients achieved a partial response (median duration of response, 9 months [range, 9–11 months]) and subsequently showed resistance to AZD9291. EGFRT790M-mutant clones depopulated AZD9291-resistant tumors to below 1% (baseline, 14%–36%) in three patients with progression: one with the loss of EGFRLREAT747del/T790M-double mutant clones and two accompanied by transformation to small-cell carcinoma and focal fibroblast growth factor receptor 1 (FGFR1) amplification, respectively. EGFRT790M-mutant clones remained and the EGFR ligand was overexpressed in one patient with focal progression to AZD9291.ConclusionAcquired resistance mechanisms of AZD9291 in patients with EGFRT790M-mutant NSCLC who failed treatment with first-generation EGFR TKIs include the loss of EGFRT790M-mutant clones plus alternative pathway activation or histologic transformation and EGFR ligand–dependent activation