Tohru Miyake

The Jmjd3- Irf4 axis regulates M2 macrophage polarization and host responses against helminth infection

Polarization of macrophages to M1 or M2 cells is important for mounting responses against bacterial and helminth infections, respectively. Jumonji domain containing-3 (Jmjd3), a histone 3 Lys27 (H3K27) demethylase, has been implicated in the activation of macrophages. Here we show that Jmjd3 is essential for M2 macrophage polarization in response to helminth infection and chitin, though Jmjd3 is dispensable for M1 responses. Furthermore, Jmjd3 (also known as Kdm6b) is essential for proper bone marrow macrophage differentiation, and this function depends on demethylase activity of Jmjd3. Jmjd3 deficiency affected trimethylation of H3K27 in only a limited number of genes. Among them, we identified Irf4 as encoding a key transcription factor that controls M2 macrophage polarization. Collectively, these results show that Jmjd3-mediated H3K27 demethylation is crucial for regulating M2 macrophage development leading to anti-helminth host responses.

Zc3h12a is an RNase essential for controlling immune responses by regulating mRNA decay

Toll-like receptors (TLRs) recognize microbial components, and evoke inflammation and immune responses. TLR stimulation activates complex gene expression networks that regulate the magnitude and duration of the immune reaction. Here we identify the TLR-inducible gene Zc3h12a as an immune response modifier that has an essential role in preventing immune disorders. Zc3h12a-deficient mice suffered from severe anaemia, and most died within 12 weeks. Zc3h12a-/- mice also showed augmented serum immunoglobulin levels and autoantibody production, together with a greatly increased number of plasma cells, as well as infiltration of plasma cells to the lung. Most Zc3h12a-/- splenic T cells showed effector/memory characteristics and produced interferon-γ in response to T-cell receptor stimulation. Macrophages from Zc3h12a-/- mice showed highly increased production of interleukin (IL)-6 and IL-12p40 (also known as IL12b), but not TNF, in response to TLR ligands. Although the activation of TLR signalling pathways was normal, Il6 messenger RNA decay was severely impaired in Zc3h12a-/- macrophages. Overexpression of Zc3h12a accelerated Il6 mRNA degradation via its 3′-untranslated region (UTR), and destabilized RNAs with 3′-UTRs for genes including Il6, Il12p40 and the calcitonin receptor gene Calcr. Zc3h12a contains a putative amino-terminal nuclease domain, and the expressed protein had RNase activity, consistent with a role in the decay of Il6 mRNA. Together, these results indicate that Zc3h12a is an essential RNase that prevents immune disorders by directly controlling the stability of a set of inflammatory genes.

Poly I:C-Induced Activation of NK Cells by CD8α+ Dendritic Cells via the IPS-1 and TRIF-Dependent Pathways

NK cells play essential roles in eliminating virally infected cells and tumor cells. Polyinosinic-polycytidylic acid (poly I:C), a double-stranded RNA analog recognized by melanoma-differentiation associated gene 5 (MDA5) and TLR3, activates NK cells in vivo. MDA5 and TLR3 signal through distinct adaptor molecules, IFN-promoter stimulator-1 (IPS-1) and Toll/IL-1R domain-containing adaptor inducing IFN-β (TRIF), respectively. However, it remains unclear how NK cells are activated by poly I:C in vivo. In this study, we demonstrate that the IPS-1-dependent and the TRIF-dependent pathways are essential for NK cell activation to poly I:C stimulation in mice, whereas deficiency in either IPS-1 or TRIF only modestly impairs the poly I:C-induced NK cell activation. Furthermore, both IPS-1 and TRIF contributed to suppression of implanted B16 tumor growth in response to poly I:C administration via NK cell activation. Presence of IPS-1 and TRIF in dendritic cells (DCs), but not NK cells, was required for production of IFN-γ to poly I:C in NK cells in vitro. Moreover CD8α+ conventional dendritic cells (cDCs), but not CD8α− cDCs, expressed genes for type I IFNs, IL-6, and IL-12p40 in response to poly I:C stimulation, and were also responsible for inducing IFN-γ production in NK cells. Taken together, poly I:C activates the IPS-1- and TRIF-dependent pathways in CD8α+ cDCs, which in turn leads to NK cell activation.

Clinical potential of an antitumor drug sensitivity test and diffusion-weighted MRI in a patient with a recurrent solid pseudopapillary tumor of the pancreas

A solid pseudopapillary tumor (SPT) of the pancreas is a rare type of pancreatic neoplasm found predominantly in young women. SPTs typically behave as though benign; however, in some cases they also have malignant potential. We encountered a rare case of a recurrent SPT that developed 4 years after the initial surgery in an elderly male patient. Abdominal computed tomography (CT) revealed that the 61-year-old patient had four intra-abdominal masses, suggesting a recurrence of SPT. The patient had a history of distal pancreatectomy due to SPT in the pancreatic tail 4 years previously. These tumors showed positive signals on diffusion-weighted magnetic resonance imaging (MRI), and were treated successfully by aggressive surgical resection. Microscopic diagnosis was compatible with recurrent tumors of SPT. A chemosensitivity test, the collagen gel droplet-embedded culture drug sensitivity test (CD-DST), showed that the resected tumors were sensitive to several antitumor drugs. We suggest that the CD-DST may be used to indicate promising antitumor agents for treating SPTs with malignant tendencies. In addition, a diffusion-weighted MRI can be useful for accurately visualizing SPTs of the pancreas.

IκBζ is essential for natural killer cell activation in response to IL-12 and IL-18

IκBζ, encoded by Nfibiz, is a nuclear IκB-like protein harboring ankyrin repeats. IκBζ has been shown to regulate IL-6 production in macrophages and Th17 development in T cells. However, the role of IκBζ in natural killer (NK) cells has not be understood. In the present study, we found that the expression of IκBζ was rapidly induced in response to IL-18 in NK cells, but not in T cells. Analysis of Nfkbiz−/− mice revealed that IκBζ was essential for the production of IFN-γ production and cytotoxic activity in NK cells in response to IL-12 and/or IL-18 stimulation. IL-12/IL-18–mediated gene induction was profoundly impaired in Nfkbiz−/− NK cells. Whereas the phosphorylation of STAT4 was normally induced by IL-12 stimulation, STAT4 was not recruited to the Ifng gene regions in Nfkbiz−/− NK cells. Acetylation of histone 3 K9 on Ifng regions was also abrogated in Nfkbiz−/− NK cells. IκBζ was recruited on the proximal promoter region of the Ifng gene, and overexpression of IκBζ together with IL-12 activated the Ifng promoter. Furthermore, Nfkbiz−/− mice were highly susceptible to mouse MCMV infection. Taken together, these results demonstrate that IκBζ is essential for the activation of NK cells and antiviral host defense responses.

Prognostic impact of CD44-positive cancer stem-like cells at the invasive front of gastric cancer

Background:The invasive tumour front may provide prognostic information. We examined the relationship between the presence of cancer stem cells (CSCs) at the invasive tumour front and prognosis in gastric cancer (GC).Methods:CD44 is a CSC marker; accordingly, CD44 standard (CD44s), CD44 variant-6 (CD44v6), and CD44 variant-9 (CD44v9) expression were examined in 123 resected primary GCs and the clinical significance of CSCs at the invasive tumour front was analysed.Results:Thirteen (10.6%), 79 (64.2%), and 47 (38.2%) GCs were CD44s-, CD44v6-, and CD44v9-positive, respectively. Patients with CD44-positive expression at the invasive tumour front had significantly poorer disease-specific survival than those with negative expression (CD44s: P<0.00001, CD44v6: P=0.013, CD44v9: P=0.0002). CD44s expression at the invasive tumour front was an independent prognostic factor in resectable GC patients (hazard ratio=3.13; 95% confidence interval, 1.09–9.01; P=0.035) and was significantly associated with peritoneal (P<0.001), lymphatic (P<0.001), and haematogenous recurrences (P=0.008). In addition, the number of CD44 isoforms expressed in cancer cells at the invasive tumour front was associated with patient prognosis. No conventional clinicopathological factors were independently associated with CD44 expression at the invasive tumour front.Conclusions:CD44-positive cancer stem-like cells at the invasive tumour front indicate poor survival and can be a unique biological prognostic factor for GC.

Diagnostic potential of endotoxin scattering photometry for sepsis and septic shock.

ABSTRACT Endotoxin scattering photometry (ESP) is a novel Limulus amebocyte lysate (LAL) assay that uses a laser light-scattering particle-counting method. In the present study, we compared ESP, standard turbidimetric LAL assay, and procalcitonin assay for the evaluation of sepsis after emergency gastrointestinal surgery. A total of 174 samples were collected from 40 adult patients undergoing emergency gastrointestinal surgery and 10 patients with colorectal cancer undergoing elective surgery as nonseptic controls. Plasma endotoxin levels were measured with ESP and turbidimetric LAL assay, and plasma procalcitonin levels were assessed with a standard procalcitonin assay. Plasma endotoxin and procalcitonin levels increased corresponding to the degree of sepsis. Endotoxin scattering photometry significantly discriminated between patients with or without septic shock: sensitivity, 81.1%; specificity, 76.6%; positive predictive value, 48.4%; negative predictive value, 93.8%; and accuracy, 77.6%. The area under the receiver operating characteristic curve for septic shock with the ESP assay (endotoxin cutoff value, 23.8 pg/mL) was 0.8532 ± 0.0301 (95% confidence interval, 0.7841–0.9030; P < 0.0001). The predictive power of ESP was superior to that of turbidimetric assay (difference, 0.1965 ± 0.0588; 95% confidence interval, 0.0812–0.3117; P = 0.0008). There was no significant difference in predictive power between ESP and procalcitonin assay. Endotoxin scattering photometry also discriminated between patients with and without sepsis. Area under the receiver operating characteristic curve analysis showed that ESP had the best predictive power for diagnosing sepsis. In conclusion, compared with turbidimetric LAL assay, ESP more sensitively detected plasma endotoxin and significantly discriminated between sepsis and septic shock in patients undergoing gastrointestinal emergency surgery.

A rare case of primary choriocarcinoma in the sigmoid colon

Primary colorectal choriocarcinoma is an extremely rare neoplasm and is usually associated with a poor prognosis. Only 13 cases of colorectal choriocarcinoma have previously been reported. There is no standard chemotherapeutic regimen for this tumor type. A 68-year-old man presented with melena and was diagnosed with sigmoid colonic adenocarcinoma with multiple liver metastases. He underwent a laparoscopic sigmoidectomy. Pathology revealed choriocarcinoma with a focal component of moderately differentiated adenocarcinoma of colon origin. Based on the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) results, mFOLFOX6 and bevacizumab were administered, which suppressed aggressive tumor growth for 4 mo. The patient died 9 mo after the initial diagnosis. Our study results suggest that the standard chemotherapy regimen for colorectal cancer might have suppressive effects against primary colorectal choriocarcinoma. Moreover, CD-DST may provide, at least in part, therapeutic insight for the selection of appropriate antitumor agents for such patients.