Rab7-Mediated Endocytosis Establishes Patterning of Wnt Activity through Inactivation of Dkk Antagonism

Endocytosis has been proposed to modulate cell signaling activities. However, the role of endocytosis in embryogenesis, which requires coordination of multiple signaling inputs, has remained less understood. We previously showed that mouse embryos lacking a small guanosine triphosphate (GTP)-binding protein Rab7 implicated in endocytic flow are defective in gastrulation. Here, we investigate how subcellular defects associated with Rab7 deficiency are related to the observed developmental defects. Rab7-deficient embryos fail to organize mesodermal tissues due to defects in Wnt-β-catenin signaling. Visceral endoderm (VE)-specific ablation of Rab7 results in patterning defects similar to systemic Rab7 deletion. Rab7 mutants accumulate the Wnt antagonist Dkk1 in the extracellular space and in intracellular compartments throughout the VE epithelium. These data indicate that Rab7-dependent endocytosis regulates the concentration and availability of extracellular Dkk1, thereby relieving the epiblast of antagonism. This intercellular mechanism therefore organizes distinct spatiotemporal patterns of canonical Wnt activity during the peri-gastrulation stages of embryonic development

Differentiation of IL-17-Producing Invariant Natural Killer T Cells Requires Expression of the Transcription Factor c-Maf

c-Maf belongs to the large Maf family of transcription factors and plays a key role in the regulation of cytokine production and differentiation of TH2, TH17, TFH, and Tr1 cells. Invariant natural killer T (iNKT) cells can rapidly produce large quantity of TH-related cytokines such as IFN-γ, IL-4, and IL-17A upon stimulation by glycolipid antigens, such as α-galactosylceramide (α-GalCer). However, the role of c-Maf in iNKT cells and iNKT cells-mediated diseases remains poorly understood. In this study, we demonstrate that α-GalCer-stimulated iNKT cells express c-Maf transcript and protein. By using c-Maf-deficient fetal liver cell-reconstituted mice, we further show that c-Maf-deficient iNKT cells produce less IL-17A than their wild-type counterparts after α-GalCer stimulation. While c-Maf deficiency does not affect the development and activation of iNKT cells, c-Maf is essential for the induction of IL-17-producing iNKT (iNKT17) cells by IL-6, TGF-β, and IL-1β, and the optimal expression of RORγt. Accordingly, c-Maf-deficient iNKT17 cells lose the ability to recruit neutrophils into the lungs. Taken together, c-Maf is a positive regulator for the expression of IL-17A and RORγt in iNKT17 cells. It is a potential therapeutic target in iNKT17 cell-mediated inflammatory disease

Laparoscopic hepatectomy for hepatic angiomyolipoma with preoperative diagnosis of other malignancy : a report of 2 cases

Background Hepatic angiomyolipoma (HAML) is a rare liver tumor, and hepatectomy is the only effective treatment. Due to the difficulty of correct diagnosis of HAML before surgery by image studies, more than 36.6% of reported HAMLs are misdiagnosed as other malignant liver tumors before surgery. As there are only few reported cases in which HAMLs were removed using laparoscopic hepatectomy, the effectiveness of laparoscopic hepatectomy for such HAMLs in which are diagnosed as other malignant liver tumor before surgery has not been reported. Case presentation Case 1: a 58-year-old female with a history of treatment for autoimmune hepatitis was preoperatively diagnosed with hepatocellular carcinoma (size: 20 mm) in segment 7 (S7) of the liver. The tumor was removed by laparoscopic partial resection and was diagnosed as a HAML through a pathological examination. The patient's postoperative course was good, and she was recurrence-free at 37 months after the hepatectomy. Case 2: a 29-year-old female with a history of surgery for a right mature cystic teratoma was referred to our department to receive treatment for a growing 20-mm liver tumor with some calcification, which arose in S3 of the liver. A metastatic liver tumor derived from the mature cystic teratoma was suspected, and laparoscopic left lateral sectionectomy was performed. The liver tumor was diagnosed as a HAML after a pathological examination. The patient's postoperative course was unremarkable, and more than 54 months have passed since the hepatectomy without any recurrence. Conclusions Two cases in which HAMLs were preoperatively diagnosed as other malignant liver tumor were successfully removed by laparoscopic hepatectomy with a correct postoperative diagnosis. Laparoscopic hepatectomy for the present 2 cases of HAML seemed to be effective for providing a correct diagnosis after the curative removement of liver tumor with a smaller invasion compared to open hepatectomy, and for denying risk of dissemination of the malignant tumor by needle biopsy that had to be considered before ruling out malignant tumor

X-ray computed tomography imaging of a tumor with high sensitivity using gold nanoparticles conjugated to a cancer-specific antibody via polyethylene glycol chains on their surface

Contrast agents are often used to enhance the contrast of X-ray computed tomography (CT) imaging of tumors to improve diagnostic accuracy. However, because the iodine-based contrast agents currently used in hospitals are of low molecular weight, the agent is rapidly excreted from the kidney or moves to extravascular tissues through the capillary vessels, depending on its concentration gradient. This leads to nonspecific enhancement of contrast images for tissues. Here, we created gold (Au) nanoparticles as a new contrast agent to specifically image tumors with CT using an enhanced permeability and retention (EPR) effect. Au has a higher X-ray absorption coefficient than does iodine. Au nanoparticles were supported with polyethylene glycol (PEG) chains on their surface to increase the blood retention and were conjugated with a cancer-specific antibody via terminal PEG chains. The developed Au nanoparticles were injected into tumor-bearing mice, and the distribution of Au was examined with CT imaging, transmission electron microscopy, and elemental analysis using inductively coupled plasma optical emission spectrometry. The results show that specific localization of the developed Au nanoparticles in the tumor is affected by a slight difference in particle size and enhanced by the conjugation of a specific antibody against the tumor