CCL5 is induced by TLR 3 signaling in HuCCT1 human biliary epithelial cells: possible involvement in the pathogenesis of biliary atresia.

Biliary atresia (BA) is a disease of the newborn that is characterized by progressive, inflammatory and sclerosing cholangiopathy. Innate immune responses to viral components are thought to be involved in the pathogenesis of BA. It is also reported that some chemokines, such as CCL5, are possibly involved in the pathogenesis of experimental animal model of BA. We treated human biliary epithelial HuCCT1 cells with polyinosinic-polycytidylic acid (poly IC), an authentic double-stranded RNA (dsRNA) which mimics viral RNA, and analyzed the CCL5 expression by quantitative reverse transcription-PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). To examine the regulation mechanisms of CCL5, we subjected the cells to RNA interference (siRNA) against Toll-like receptor 3 (TLR3), interferon (IFN)-ß, NF-κB p65 and IFN regulatory factor (IRF) 3. Immunohistochemical staining for CCL5 was also performed in tissues from patients with BA. Poly IC induced CCL5 expression in HuCCT1 cells. CCL5 expression induced by poly IC was inhibited by the knockdown of TLR3, p65 or IRF3, but it was not affected by knockdown of IFN-ß. Immunohistochemical staining showed that CCL5 was strongly expressed in biliary epithelial cells of patients with BA. The current study suggests that TLR3 signaling induces CCL5 expression via NF-κB and IRF3 in bile duct cells, and this pathway may be involved in the pathogenesis of BA.

Interferon (IFN)-induced protein 35 (IFI35) negatively regulates IFN-ß-phosphorylated STAT1-RIG-I-CXCL10/CCL5 axis in U373MG astrocytoma cells treated with polyinosinic-polycytidylic acid.

Interferon (IFN)-stimulated genes (ISGs) exert multiple functions in immune system. IFN-induced protein 35 (IFI35) is a member of ISGs, and has been suggested to regulate innate immune reaction. However, the physiological functions and pathological roles of IFI35 in the central nervous system are not characterized well. In the present study, we found that the expression of IFI35 was induced by a Toll-like receptor 3 (TLR3) ligand polyinosinic-polycytidylic acid (poly IC) in U373MG human astrocytoma cells. Knockdown of IFI35 using RNA interference resulted in increased expression of IFN-ß, phosphorylated STAT1 (P-STAT1), retinoic acid-inducible gene-I (RIG-I), CXCL10 and CCL5 induced by poly IC. Poly IC-induced expression of CXCL10 and CCL5 was decreased by knockdown of RIG-I. These results suggest that IFI35 may negatively regulate the TLR3-IFN-ß-P-STAT1-RIG-I-CXCL10/CCL5 axis in U373MG cells, and IFI35 may play a role at least partially in the regulation of innate immune reactions in astrocytes.

Interferon-Stimulated Gene 15, a Type I Interferon-Dependent Transcript, Is Involved in a Negative Feedback Loop in Innate Immune Reactions in Human Mesangial Cells.

BACKGROUND: Since innate immunity plays a pivotal role in the pathogenesis of glomerulonephritis, the activation of toll-like receptor (TLR) 3/type I interferon (IFN) cascades is important in glomerular inflammation. However, the role of IFN-stimulated gene 15 (ISG15), a type IFN-dependent transcript, in glomerular inflammation is unclear. We, therefore, examined the role of ISG15 in innate immune reactions induced by TLR3 signaling in cultured human mesangial cells (MCs). METHODS: We treated MCs with polyinosinic-polycytidylic acid (poly IC), an authentic double-stranded RNA, and analyzed the ISG15 expression by reverse transcription-polymerase chain reaction and western blotting. To examine the regulation of ISG15 expression, we subjected MCs to RNA interference (siRNA) against TLR3, IFN-ß, ISG56, and melanoma differentiation-associated gene 5 (MDA5). RESULTS: ISG15 expression induced by poly IC in MCs was inhibited by siRNA against TLR3 and IFN-ß, whereas silencing of ISG56 or MDA5 had no effect. A knockdown of ISG15 upregulated the expression of ISG56, MDA5, CXCL10 and phosphorylated signal transducers and activators of transcription protein 1 (P-STAT1), while a knockdown of ubiquitin-like modifier activating enzyme 7, a key enzyme that conjugates ISG15 to target proteins, did not affect the expression. Knockdown of ubiquitin specific protease 18, an ISG15 isopeptidase, also upregulated P-STAT1, ISG56, MDA5 and CXCL10. CONCLUSION: Since unconjugated free ISG15 negatively regulates the phosphorylation of STAT1 and its downstream reactions, ISG15 dysregulation may be involved in the pathogenesis of glomerular inflammation. We believe that suitable interventions in these innate immune cascades is desirable for the future therapeutic strategies for glomerulonephritis.

[A case of pneumatosis cystoides intestinalis after neoadjuvant chemotherapy for esophageal cancer].

A man in his 60s was diagnosed with esophageal cancer (T3, N0, StageII) and treated with 5-fluorouracil and cisplatin as neoadjuvant chemotherapy (NAC). On day 18 of the second NAC course, the patient developed febrile neutropenia, and a computed tomography (CT) scan showed pneumatosis cystoides intestinalis (PCI) of the ascending and transverse colon, free air around the ascending colon, thickening of the gallbladder wall, pleural effusion, and ascites. Because there were no signs of peritoneal irritation and intestinal perforation was ruled out, conservative treatment was selected. Seven days after PCI was diagnosed, CT showed improvement in PCI and the free air had disappeared, and 26 days after the diagnosis, a subtotal esophagectomy was performed. Observation of the abdomen did not show a thickened wall or stenosis of the ascending or transverse colon. PCI could be treated conservatively, even with free air in the abdominal cavity, by comprehensively assessing not only the imaging but also the physical findings. We were able to perform radical resection of the esophageal cancer without excessive treatment for PCI.

Jejunal intussusception associated with lymphoma in a horse.

A 2-year-old Thoroughbred horse presented with acute onset of colitis, and the intussuscepted jejunum was surgically resected. A transmural mass protruding into the lumen was found at the leading edge of the intussusceptum. Based on histological and immunohistochemical examinations, the mass was diagnosed as diffuse large B-cell lymphoma with metastasis to the mesenteric lymph nodes. Anatomical localization of the mass in the intussusception and absence of other obvious underlying diseases indicated that the intussusception had occurred in association with the mass. To our knowledge, this case is the first report of equine intussusception associated with focal intestinal lymphoma.