NKT lymphocyte polarization determined by microenvironment signaling: a role for CD8+ lymphocytes and beta-glycosphingolipids

Natural killer T-cell (NKT) regulatory lymphocytes have been shown to behave differently in various immune settings. The aim of the present study was to determine the effect of microenvironmental signaling on NKT polarization and the process of active CD8 and NKT intrahepatic lymphocyte sequestration. In an in vitro assay, double negative (DN) NKT hybridoma cells were incubated with Hep3B hepatoma cells. This caused a significant increase in the secretion of alpha-fetoprotein (AFP) from Hep3B cells. When NKT cells were exposed to beta-glucoslyceramide (beta-GC) prior to incubation, Hep3B cells exhibited increased proliferation, increased IFN secretion, and reduced AFP secretion. In vivo, the adoptive transfer of na?ve DN NKT cells into athymic nude-nu mice transplanted with human Hep3B hepatocellular carcinoma (HCC) caused accelerated tumor growth. This effect was inhibited by prior ex vivo exposure of DN NKT lymphocytes to beta-GC. To assess the effect of the immunological environment on NKT cells, immune mediated hepatitis and colitis were induced simultaneously in mice. Induction of TNBS colitis prior to administration of concanavalin A (Con A) hepatitis resulted in an aggravation of the liver damage caused by Con A hepatitis alone. This effect was associated with reduced intrahepatic CD8+ T cell trapping and an increase in intrahepatic NKT cells. The presence of different ligands altered host microenvironment signaling and influenced the fate and polarization of NKT cells and the sequestration of active intrahepatic lymphocytes. These data support the notion that NKT regulatory lymphocytes have an inherent plasticity that may be important for their regulatory function.     

Heparanase enhances early hepatocyte inclusion in the recipient liver after transplantation in partially hepatectomized rats

Hepatocyte transplantation is an emerging approach for the treatment of liver diseases. However, broad clinical application of this method has been limited by restricted source of cells and low efficiency of cell integration within the recipient liver. Heparanase cleaves heparan sulfate proteoglycans in the extracellular matrix and basement membrane, activity that affects cellular invasion associated with cancer metastasis and inflammation. This activity has a multifunctional effect on cell-cell interaction, cell adhesion, and angiogenesis. All these factors are important for successful integration of transplanted hepatocytes. Male donor hepatocytes pretreated with heparanase or untreated were transplanted into recipient female rat spleen following partial hepatectomy. Engraftment efficacy was evaluated by PCR for Y chromosome, histology and PCNA, and heparanase immunohistochemistry. In addition, proliferative activity of hepatocytes in vitro was determined by bromodeoxyuridine immunostaining. The number of heparanase-treated cells detected in the recipient liver was significantly increased three- to fivefold within 24-48 h posttransplantation and twofold at 14 days compared with untreated cells. The transplanted hepatocytes treated with heparanase were clearly seen inside portal vein radicles as cell aggregates up to 72 h posttransplantation. The number of portal radicles filled with heparanase-treated hepatocytes was increased compared to control early after transplantation. Heparanase treatment enhanced hepatocyte and sinusoidal endothelial cell proliferation in the liver, and hepatocyte proliferation within the spleen tissue. Preliminary in vitro studies with isolated hepatocytes treated with heparanase showed increased proliferative activity within 24-48 h of cell culture. These results suggest that preincubation of hepatocytes with heparanase increases the presence of hepatocytes within the recipient liver early following cell transplantation and stimulates both hepatocyte and sinusoidal endothelial cell proliferation.     

Distress and anxiety associated with COVID-19 among Jewish and Arab pregnant women in Israel

ABSTRACT

Introduction

The fact that little is yet known about the possible implications of COVID-19 for pregnancy, puts pregnant women at greater risk of heightened anxiety and psychological distress. In this study, we sought to explore the psychological distress and COVID-19-related anxiety of pregnant women during the crisis.     

Right ductus arteriosus: facts and theory

ObjectiveTo report fetal right-sided persistent ductus arteriosus (RPDA) in association with right aortic arch (RAA).Study designExtensive sonographic fetal anatomical scans were consecutively performed on 19,874 private, self-referred pregnant women who wanted early sonographic detection of fetal anomalies.ResultsOf 19,874 transvaginal (TVS) sonographic examinations 40 fetuses had right aortic arch (RAA) and four of them (10%) had RPDA. We also diagnosed seven cases of RPDA with involvement of the left aortic arch where a right-curving pattern (“L” shape) parallel to the right pulmonary artery was suggestive of Rt. DA with left aortic arch. Only one (9%) of the RPDA cases was associated with a cardiac anomaly (double outlet right ventricle). None of the other eight RPDA cases had any discernible anomalies, and all of the fetuses with RPDA had normal karyotypes.ConclusionsIn 10% of the fetuses with right aortic arch the ductal arch was also on the right side. An unusual-looking DA may be a RPDA associated with the left aortic arch.In most cases, the RPDA is a normal variant not associated with other anomalies.     

Genetic testing for hearing loss: different motivations for the same outcome

Autism is a complex genetic disorder. Chromosome 15 is of particular interest in this disorder, because of previous reports of individuals with autism with chromosomal abnormalities in the 15q11-q13 region. Transmission disequilibrium between polymorphisms in this region and autism has been also been reported in some, but not all studies. Recently, a novel maternally expressed gene, ATP10C, was characterized and mapped to the chromosome 15q11-q13 region, 200 kb distal to UBE3A. It encodes a putative aminophospholipid translocase likely to be involved in the asymmetric distribution of proteins in the cell membrane. Preferential maternal expression has been demonstrated in fibroblasts and brain. Because of its physical location and imprinting pattern, ATP10C was considered to be a candidate gene for chromosome 15-associated autism. In an effort to find the genes responsible for autism in this chromosomal region, 1.5 kb of the 5' flanking region, as well as the coding and splicing regions of ATP10C, were screened for sequence variants. Several polymorphic markers including five nonsynonymous SNPs were identified. To investigate transmission disequilibrium between ATP10C and autism, a family-based association study was conducted for 14 markers in 115 autism trios. No significant transmission disequilibrium was found, suggesting ATP10C is unlikely to contribute strongly to susceptibility to autism in these families. However, due to limited power to detect genes of modest effect, the possible functional role of the nonsynonymous SNPs and the functional implications of the SNPs identified from 5' flanking region and intron 2 splicing region may be evaluated in further studies.     

Immune-deficient SCID and NOD/SCID mice models as functional assays for studying normal and malignant human hematopoiesis

 Many events and requirements of the developmental program of human hematopoietic stem cells have not yet been discovered. A major impediment has been the lack of an appropriate experimental system. At present the conditions for maintaining human stem cells in vitro are not fully known. As a result within a short period the small stem cell pool is lost due to differentiation, making it difficult to examine the correlation between these cells and their function in vivo. Most of our knowledge of hematopoietic stem cells is from animal models in which purified stem cell canididates are assayed based on their functional ability to rescue lethally conditioned recipients. The permanent correction of many genetic disorders of the hematopoietic system requires efficient methods for introducing genes into stem cells in vitro. However, progress has been hindered by the absence of preclinical models that assay the repopulating capacity of primitive human cells. In addition, the development of therapy for malignant diseases also requires assays to identify the target leukemic stem cells based on their ability to initiate the disease. The recent development of methods to transplant or implant both normal and leukemic cells into immune-deficient mice provides the foundation for human stem cell assays. These models assay the repopulating capacity of primitive human cells and provide an important approach to identify and characterize human stem cells, both normal and leukemic. This review focuses on the development of functional assays for normal and leukemic human stem cells and on the new insights that these models are beginning to provide on the organization of the human stem cell hierarchy. Received: 27 January 1997 / Accepted: 3 April 1997