The influence of lysophosphatidic acid on the immunophenotypic differentiation of human monocytes into dendritic cells.

Lysophosphatidic acid (LPA), a naturally occurring phospholipid, has been suggested to have an immunoregulatory role. We investigated the effect of LPA on differentiation of human monocytes into dendritic cells (DC). We found that LPA affects DC differentiation from monocytes by blocking the expression of CD1a molecules on their surface in a dose-dependent manner.

Influence of pertussis toxin on CD1a isoform expression in human dendritic cells.

Pertussis toxin (PTX) is an exotoxin produced by Bordetella pertussis. It is known to exert adjuvant activities inducing Th1-launched immune responses. In this study, we show that PTX can selectively block the expression of CD1a isoform during the differentiation of human monocytes into dendritic cells.

Hepatocyte growth factor effects on mesenchymal stem cells: proliferation, migration, and differentiation.

Hepatocyte growth factor (HGF), a pleiotropic cytokine of mesenchymal origin promoting migration, proliferation, and survival in a wide spectrum of cells, can also modulate different biological responses in stem cells, but the mechanisms involved are not completely understood so far. In this context, we show that short-term exposure of mesenchymal stem cells (MSCs) to HGF can induce the activation of its cognate Met receptor and the downstream effectors ERK1/2, p38MAPK, and PI3K/Akt, while long-term exposure to HGF resulted in cytoskeletal rearrangement, cell migration, and marked inhibition of proliferation through the arrest in the G1-S checkpoint. When added to MSCs, the K252A tyrosine kinase inhibitor prevented HGF-induced responses.

Atrial natriuretic peptide effects on intracellular pH changes and ROS production in HEPG2 cells: role of p38 MAPK and phospholipase D.

Aims: The present study was performed to evaluate Atrial Natriuretic Peptide (ANP) effects on intracellular pH, phospholipase D and ROS production and the possible relationship among them in HepG2 cells. Cancer extracellular microenvironment is more acidic than normal tissues and the activation of NHE-1, the only system able to regulate pHi homeostasis in this condition, can represent an important event in cell proliferation and malignant transformation.

Methods: The ANP effects on pHi were evaluated by fluorescence spectrometry.