Flt3 ligand treatment modulates parasitemia during infection with rodent malaria parasites via MyD88- and IFN-γ-dependent mechanisms

We previously showed that treatment of mice with the Flt3 ligand (Flt3L) prevents development of lethal experimental cerebral malaria and inhibits parasitemia during Plasmodium berghei ANKA (PbA) infection. In this study, we investigated the mechanisms underlying the reduction of parasitemia in Flt3L-treated mice. Studies using gene knockout mice and antibody treatment indicated that the anti-parasitemia effect of Flt3L was mediated by innate immune system and was dependent on MyD88, IFN-γ, IL-12 and natural killer (NK) cells. The number of NK cells and their ability to produce IFN-γ was enhanced in Flt3L-treated mice. Phagocytic activity of splenocytes was increased in Flt3L-treated mice after PbA infection when compared with that in untreated mice, and this activity was mainly mediated by the accumulation of F4/80(mid) CD11b(+) cells in the spleen. In both MyD88(-/-) and IFN-γ(-/-) mice, the proportion of F4/80(mid) CD11b(+) cells was not increased in the spleen of Flt3L-treated mice after infection. These correlations suggest that NK cells produce IFN-γ in Flt3L-treated mice, and accumulation of F4/80(mid) CD11b(+) cells in the spleen is promoted by an IFN-γ -dependent manner, culminating in the inhibition of parasitemia. These findings imply that Flt3L promotes effective innate immunity against malaria infection mediated by interplay among varieties of innate immune cells.

Transcriptional regulation of immediate-early gene response by THOC5, a member of mRNA export complex, contributes to the M-CSF-induced macrophage differentiation

Hematopoiesis and commitment to a restricted lineage are guided by a timely expressed set of cytokine receptors and their downstream transcription factors. A member of the mRNA export complex, THOC5 (suppressors of the transcriptional defects of hpr1 delta by overexpression complex 5) is a substrate for several tyrosine kinases such as macrophage colony-stimulating factor (M-CSF) receptor and various leukemogenic tyrosine kinases, such as Bcr-Abl, or NPM-ALK. THOC5 tyrosine phosphorylation is elevated in stem cells from patients with chronic myeloid leukemia, suggesting that THOC5 may be involved in leukemia development. THOC5 is also an essential element in the maintenance of hematopoiesis in adult mice. In this report, we show that THOC5 is located in the nuclear speckles, and that it is translocated from the nucleus to cytoplasm during M-CSF-induced bone marrow-derived macrophage differentiation. Furthermore, we have identified THOC5 target genes by trancriptome analysis, using tamoxifen-inducible THOC5 knockout macrophages. Although only 99 genes were downregulated in THOC5-depleted macrophages, half of the genes are involved in differentiation and/or migration. These include well-known regulators of myeloid differentiation inhibitor of DNA binding (Id)1, Id3, Smad family member 6 (Smad6) and Homeobox (Hox)A1. In addition, a subset of M-CSF-inducible genes, such as Ets family mRNAs are THOC5 target mRNAs. Upon depletion of THOC5, unspliced v-ets erythroblastosis virus E26 oncogene homolog (Ets1) mRNA was accumulated in the nucleus. Furthermore, THOC5 was recruited to chromatin where Ets1 was transcribed and bound to unspliced and spliced Ets1 transcripts, indicating that THOC5 has a role in processing/export of M-CSF-inducible genes. In conclusion, regulation of immediate-early gene response by THOC5, a member of mRNA export complex contributes to the M-CSF-induced macrophage differentiation.

Phase 1 study of lenvatinib combined with carboplatin and paclitaxel in patients with non-small-cell lung cancer

BACKGROUND

This dose-finding study evaluated lenvatinib, an oral multitargeted receptor tyrosine kinase inhibitor, in combination with carboplatin/paclitaxel in chemotherapy-naïve non-small-cell lung cancer (NSCLC) patients.

PATIENTS AND METHODS

Patients received lenvatinib twice daily (BID) with carboplatin (area under the curve 6 mg ml(-1) min(-1), day 1)/paclitaxel (200 mg m(-2), day 1) every 3 weeks. The initial dose of lenvatinib was 6 mg BID. The primary end point was maximum tolerated dose (MTD) of lenvatinib. At the MTD, the cohort was expanded by 16 patients. Safety, pharmacokinetics, pharmacodynamics, and antitumor effects were evaluated.

RESULTS

Twenty-eight patients were treated. At 6 mg BID, dose-limiting toxicities (DLTs) included febrile neutropenia/gingival infection (n=2). No DLTs occurred with 4 mg BID, the recommended MTD for the expansion. Common grade 3/4 toxicities included neutropenia, leukopenia, hypertension, and thrombocytopenia. The combination had no significant impact on individual drug pharmacokinetics. Response rate and median progression-free survival were 68% and 9.0 months, respectively, with 4 mg BID. In the plasma biomarker analysis, stromal cell-derived factor 1α, stem cell factor, and granulocyte colony-stimulating factor correlated with antitumor activity.

CONCLUSION

The MTD for lenvatinib with carboplatin/paclitaxel is 4 mg BID in advanced NSCLC patients. This regimen demonstrated manageable tolerability and encouraging antitumor activity.

Activin A is stimulated by tumor necrosis factor-alpha and modulates collagen gene expression in human amniotic cells

BACKGROUND

Accumulating evidence supports the idea of activin A as a modulator of inflammation. In human pregnancy, elevated activin A concentrations in amniotic fluid are reported in women with intra-amniotic infection and inflammation- induced pre-term birth.

AIM

To test the hypothesis that activin A was involved in the pathophysiology of amnionitis, we evaluated the effects of tumor necrosis factor-α and lipopolysaccharide on activin A production in human amniotic epithelial cells, and the effects of activin A on the expression of collagen mRNA in amniotic mesenchymal cells.

MATERIALS AND METHODS

Amniotic membranes were obtained from patients without systemic disease, signs of premature delivery or fetal complications, during elective cesarean sections at term. Amniotic epithelial cells and mesenchymal cells were separately obtained by enzymatic digestion and cultured. Activin A was measured by enzyme-linked immunosorbent assay and collagen mRNA levels were assessed by quantitative PCR.

RESULTS

Amniotic epithelial cells produced activin A in a cell density- and time-dependent manner. Tumor necrosis factor- α enhanced activin A production in a time-dependent (48-120 h) and dose-dependent (10-300 ng/ml) manner in amniotic epithelial cells. Lipopolysaccharide also stimulated activin A production, but the effect was less prominent. In amniotic mesenchymal cells, the effect of activin A on the expression of type I and type III collagen mRNA was suppressive.

CONCLUSIONS

Tumor necrosis factor-α and lipopolysaccharide stimulated activin A production in amniotic epithelial cells, and activin A modulated expression of collagen mRNA in amniotic mesenchymal cells. These results support the idea that activin A is involved in the pathophysiology of amnionitis.

Gene silencing in Escherichia coli using antisense RNAs expressed from doxycycline-inducible vectors

Here, we report on the construction of doxycycline (tetracycline analogue)-inducible vectors that express antisense RNAs in Escherichia coli. Using these vectors, the expression of genes of interest can be silenced conditionally. The expression of antisense RNAs from the vectors was more tightly regulated than the previously constructed isopropyl-β-D-galactopyranoside-inducible vectors. Furthermore, expression levels of antisense RNAs were enhanced by combining the doxycycline-inducible promoter with the T7 promoter-T7 RNA polymerase system; the T7 RNA polymerase gene, under control of the doxycycline-inducible promoter, was integrated into the lacZ locus of the genome without leaving any antibiotic marker. These vectors are useful for investigating gene functions or altering cell phenotypes for biotechnological and industrial applications.

SIGNIFICANCE AND IMPACT OF THE STUDY

A gene silencing method using antisense RNAs in Escherichia coli is described, which facilitates the investigation of bacterial gene function. In particular, the method is suitable for comprehensive analyses or phenotypic analyses of genes essential for growth. Here, we describe expansion of vector variations for expressing antisense RNAs, allowing choice of a vector appropriate for the target genes or experimental purpose.

A comparison between intraductal papillary neoplasms of the biliary tract (BT-IPMNs) and intraductal papillary mucinous neoplasms of the pancreas (P-IPMNs) reveals distinct clinical manifestations and outcomes

BACKGROUND

Intraductal papillary mucinous neoplasm of the biliary tract (BT-IPMN) has been increasingly recognized as a biliary counterpart of intraductal papillary mucinous neoplasm of the pancreas (P-IPMN). However, there is limited information regarding whether BT-IPMNs and P-IPMNs behave in a similar fashion.

METHODS

We retrospectively compared clinicopathological variables between 9 patients with BT-IPMN and 44 patients with P-IPMN.

RESULTS

There was no significant difference in age between patients with BT-IPMN and those with P-IPMN. The male/female ratio was significantly higher in patients with P-IPMN than in those with BT-IPMN (P = 0.012). Clinical presentation with jaundice was more common in patients with BT-IPMN (67%) than in those with P-IPMN (4.5%, P = 0.002). In addition, serum levels of CEA and CA19-9 were higher in patients with BT-IPMN than in those with P-IPMN (P = 0.019 and P = 0.002, respectively). The pathological diagnosis of malignancy was significantly more common in patients with BT-IPMN (89%) than in those with P-IPMN (23%, P = 0.002). The association with invasive carcinoma was significantly more frequent in patients with BT-IPMN (44.4%) than in those with P-IPMN (6.8%, P = 0.008). Furthermore, survival time after surgical resection was significantly shorter in patients with BT-IPMN than in those with P-IPMN (P = 0.002).

CONCLUSION

These findings reveal differences in clinicopathological features and prognosis between BT-IPMN and P-IPMN, thereby suggesting distinct biological pathways underlying the pathogenesis of these neoplasms.