Pluripotency gene expression and growth control in cultures of peripheral blood monocytes during their conversion into programmable cells of monocytic origin (PCMO): evidence for a regulatory role of autocrine activin and TGF-β.

Previous studies have shown that peripheral blood monocytes can be converted in vitro to a stem cell-like cell termed PCMO as evidenced by the re-expression of pluripotency-associated genes, transient proliferation, and the ability to adopt the phenotype of hepatocytes and insulin-producing cells upon tissue-specific differentiation. However, the regulatory interactions between cultured cells governing pluripotency and mitotic activity have remained elusive. Here we asked whether activin(s) and TGF-β(s), are involved in PCMO generation.

Rac1b negatively regulates TGF-β1-induced cell motility in pancreatic ductal epithelial cells by suppressing Smad signalling.

Transforming growth factor (TGF)-β1 promotes progression of pancreatic ductal adenocarcinoma (PDAC) by enhancing epithelial-mesenchymal transition, cell migration/invasion, and metastasis, in part by cooperating with the small GTPase Rac1. Prompted by the observation of higher expression of Rac1b, an alternatively spliced Rac1 isoform, in pancreatic ductal epithelial cells and in patients with chronic pancreatitis vs. PDAC, as well as in long-time vs.

Aberrant expression and secretion of heat shock protein 90 in patients with bullous pemphigoid.

The cell stress chaperone heat shock protein 90 (Hsp90) has been implicated in inflammatory responses and its inhibition has proven successful in different mouse models of autoimmune diseases, including epidermolysis bullosa acquisita. Here, we investigated expression levels and secretory responses of Hsp90 in patients with bullous pemphigoid (BP), the most common subepidermal autoimmune blistering skin disease. In comparison to healthy controls, the following observations were made: (i) Hsp90 was highly expressed in the skin of BP patients, whereas its serum levels were decreased and inversely associated with IgG autoantibody levels against the NC16A immunodominant region of the BP180 autoantigen, (ii) in contrast, neither aberrant levels of circulating Hsp90 nor any correlation of this protein with serum autoantibodies was found in a control cohort of autoimmune bullous disease patients with pemphigus vulgaris, (iii) Hsp90 was highly expressed in and restrictedly released from peripheral blood mononuclear cells of BP patients, and (iv) Hsp90 was potently induced in and restrictedly secreted from human keratinocyte (HaCaT) cells by BP serum and isolated anti-BP180 NC16A IgG autoantibodies, respectively.

Pathogenicity of autoantibodies in anti-p200 pemphigoid.

Recently, the C-terminus of laminin γ1 has been identified as target antigen in anti-p200 pemphigoid and the disease was renamed as anti-laminin γ1 pemphigoid. However, the pathogenic relevance of these autoantibodies has not yet been demonstrated. Therefore, we employed an ex vivo model of autoantibody-mediated leukocyte-dependent neutrophil activation and dermal-epidermal separation (DES) using cryosections of human skin.

Enzymatic autoantibody glycan hydrolysis alleviates autoimmunity against type VII collagen.

Autoantibody-mediated diseases comprise a heterogeneous group of disorders in which the pathogenic potential of autoantibodies has been clearly demonstrated. In general, their treatment relies on the long-term use of systemic corticosteroids and other immunosuppressants that are associated with considerable adverse reactions. EndoS, an endoglycosidase derived from Streptococcus pyogenes, specifically hydrolyzes the N-linked glycan of native IgG and has previously been shown to modulate the interaction between the Fc portion of autoantibody and Fcγ receptors on leukocytes.

Differential roles of Smad2 and Smad3 in the regulation of TGF-β1-mediated growth inhibition and cell migration in pancreatic ductal adenocarcinoma cells: control by Rac1.

Background: Progression of pancreatic ductal adenocarcinoma (PDAC) is largely the result of genetic and/or epigenetic alterations in the transforming growth factor-beta (TGF-β)/Smad signalling pathway, eventually resulting in loss of TGF-β-mediated growth arrest and an increase in cellular migration, invasion, and metastasis. These cellular responses to TGF-β are mediated solely or partially through the canonical Smad signalling pathway which commences with activation of receptor-regulated Smads (R-Smads) Smad2 and Smad3 by the TGF-β type I receptor. However, little is known on the relative contribution of each R-Smad, the possible existence of functional antagonism, or the crosstalk with other signalling pathways in the control of TGF-β1-induced growth inhibition and cell migration.

The Src family kinase inhibitors PP2 and PP1 block TGF-beta1-mediated cellular responses by direct and differential inhibition of type I and type II TGF-beta receptors.

Both the nonreceptor tyrosine kinase Src and the receptors for transforming growth factor (TGF)-β (TβRI, TβRII) play major roles during tumorigenesis by regulating cell growth, migration/invasion and metastasis. The common Src family kinase inhibitors PP2 and PP1 effectively block Src activity in vitro and in vivo, however, they may exert non-specific effects on other kinases. In this study, we have evaluated PP2 and PP1 for their ability to inhibit TGFβ1-mediated responses in the TGF-β-responsive pancreatic adenocarcinoma cell line Panc1.

Differential roles of Src in transforming growth factor-ß regulation of growth arrest, epithelial-to-mesenchymal transition and cell migration in pancreatic ductal adenocarcinoma cells.

Both transforming growth factor (TGF)-ß and the non-receptor tyrosine kinase Src play major roles during tumorigenesis by regulating cell growth, epithelial-to-mesenchymal transition (EMT), migration/invasion and metastasis, but little is known about the signaling crosstalk between them. To interfere with Src function in vitro and in vivo many studies have employed the pharmacologic Src inhibitors PP2 and PP1. Both agents have recently been shown to be powerful inhibitors of TGF-ß receptor type I/ALK5 and type II.

The generation of programmable cells of monocytic origin involves partial repression of monocyte/macrophage markers and reactivation of pluripotency genes.

We have recently demonstrated that peripheral blood monocytes can be differentiated in vitro into hepatocyte-like cells using appropriate differentiation media. Phenotype conversion required prior in vitro culture in the presence of M-CSF, IL-3, and human serum, during which the cells acquired a state of plasticity, so were termed "programmable cells of monocytic origin" (PCMO). Here, we have further characterized the process of PCMO generation with respect to markers of monocyte-to-macrophage transition and pluripotency.

Antitumor activity of ALK1 in pancreatic carcinoma cells.

In this study, the authors investigated the expression of activin receptor-like kinase 1 (ALK1) in pancreatic carcinoma and evaluated its potential role as a tumor suppressor in vitro and in vivo. Endogenous ALK1 expression was demonstrated by immunohistochemistry in both pancreatic tumor tissue and peritumoral normal tissue from 6 patients and by RT-PCR in 8/12 established pancreatic cancer cell lines. Ectopic expression of a constitutively active (ca) ALK1 mutant in TGF-beta sensitive PANC-1 and COLO-357 cells augmented transcriptional activation of a Smad2/3 responsive reporter, and slowed down basal growth in vitro.

Adhesion and Rac1-dependent regulation of biglycan gene expression by transforming growth factor-beta. Evidence for oxidative signaling through NADPH oxidase.

Both transforming growth factor-beta (TGF-beta)-induced expression of biglycan (BGN) and activation of p38 MAPK have been implicated in cellular adhesion and migration. Here, we analyzed the role of adhesive events and the small GTPase Rac1 in TGF-beta regulation of BGN. TGF-beta1 induction of BGN expression and activation of p38 was abolished or strongly reduced when cells were kept in suspension or exposed to either the actin cytoskeleton-disrupting agent cytochalasin D or a specific chemical Rac1 inhibitor.

Transforming growth factor-beta (TGF-beta) type I receptor/ALK5-dependent activation of the GADD45beta gene mediates the induction of biglycan expression by TGF-beta.

We have recently shown that induction of biglycan (BGN) expression by transforming growth factor-beta1 (TGF-beta1) required sequential activation of both Smad and p38 mitogen-activated protein kinase signaling (Ungefroren, H., Lenschow, W., Chen, W.