Analysing cell-free plasma DNA and SLE disease activity.

Background: Over the years, the demonstration and confirmation of cell-free DNA in the circulation has increasingly been recognized as a valuable diagnostic tool. Likewise, it has been known for some time that DNA structures that are targeted by auto-antibodies play a central role in systemic lupus erythematosis (SLE) and that DNA-antibody complexes in the circulation are one of the hallmarks of SLE. Investigating whether and to what degree fluctuations in free plasma DNA levels in patients with SLE might correspond to disease severity was therefore the goal of this investigation.

Epigenetic regulation of dendritic cell differentiation and function by oxidized phospholipids.

Dendritic cells (DCs) are the key cell type in the regulation of an adaptive immune response. Under inflammatory conditions monocytes can give rise to immunostimulatory DCs, depending on microenvironmental stimuli. Here we show that oxidized phospholipids (Ox-Pls), which are generated during inflammatory reactions, dysregulate the differentiation of DCs.

NF-kappaB independent activation of a series of proinflammatory genes by hydrogen sulfide.

A stress response has the potential to induce greater resistance to subsequent stress damage. We tested whether hydrogen sulfide (H(2)S), an important signaling molecule, also used therapeutically, and known for detrimental effects, might induce a protective stress response. Therefore, the response of fibroblast-like synoviocytes (FLS) treated with sodium hydrosulfide and mice exposed to H(2)S were examined.

The ssRNA genome of human rhinovirus induces a type I IFN response but fails to induce maturation in human monocyte-derived dendritic cells.

Dendritic cells (DCs) use pattern recognition receptors to sense invading viruses and triggering of these receptors induces a maturation program. Human rhinoviruses (HRVs) belong to the family of Picornaviridae, which have a single-stranded, coding RNA genome. Because HRV does not replicate in DCs, we used genomic RNA from HRV in this study to analyze the impact of natural occurring viral ssRNA on DC function.

Liver X receptors interfere with cytokine-induced proliferation and cell survival in normal and leukemic lymphocytes.

Liver X receptors (LXRs) are nuclear receptors regulating lipid and cholesterol metabolism. Recent data indicate an additional role of LXR in immunity by controlling dendritic cell and T-cell function and in breast and prostate cancer cells. Here, we show that LXR activation interferes with IL-2 and IL-7-induced proliferation and cell cycle progression of human T-cell blasts mainly through inhibited phosphorylation of the retinoblastoma protein and decreased expression of the cell cycle protein cyclin B.

Short term hyperthermia prevents the activation of mitogen-activated protein kinase p38.

We demonstrated earlier that hyperthermia (HT), a form of balneotherapy, suppresses transcription and translation of a number of pro-inflammatory genes. Here we show that short term HT not only acts by preventing the activation of NF-kappaB, but also by blocking the activation of the MAPK p38. Data are presented that show that the effects of HT on p38 are clearly independent of HT effects on NF-kappaB.

Comparison of PCR methods for detecting fetal RhDin maternal plasma.

Background: Aim of this study was to establish the method yielding the highest sensitivity routinely used to determine fetal RhD type and gender from maternal cell-free plasma DNA in different periods of gestation.

Methods: Plasma DNA concentrations were measured from 46 pregnant women in different gestational periods and tested for RhD using three different PCR methods on exon 7: Thermal Cycler, Taqman method on LightCycler, and melting curve analysis on LightCycler. In addition, fetal gender was determined by PCR.

The TSC-mTOR signaling pathway regulates the innate inflammatory response.

The innate inflammatory immune response must be tightly controlled to avoid damage to the host. Here, we showed that the tuberous sclerosis complex-mammalian target of rapamycin (TSC-mTOR) pathway regulated inflammatory responses after bacterial stimulation in monocytes, macrophages, and primary dendritic cells. Inhibition of mTOR by rapamycin promoted production of proinflammatory cytokines via the transcription factor NF-kappaB but blocked the release of interleukin-10 via the transcription factor STAT3.

Effects of ultra-marathon on circulating DNA and mRNA expression of pro- and anti-apoptotic genes in mononuclear cells.

We investigated the effects of an ultra-marathon on cell-free plasma DNA as well as on mRNA expression of pro-apoptotic (Bax, Bad), anti-apoptotic (Bcl-2) and cell-protective (Hsp70, Hsp27 and Hsp32) genes in mononuclear blood cells (MNCs). Blood samples were drawn from 14 athletes before and immediately after 6-h run. In addition, blood samples were also collected and analyzed 2 and 24 h after the end of the run.

Hyaluronan production in synoviocytes as a consequence of viral infections: HAS1 activation by Epstein-Barr virus and synthetic double- and single-stranded viral RNA analogs.

One of the hallmarks of arthritis is swollen joints containing unusually high quantities of hyaluronan. Intact hyaluronan molecules facilitate cell migration by acting as ligands for CD44. Hyaluronan degradation products, readily formed at sites of inflammation, also fuel inflammatory processes.

Apis mellifera venom and melittin block neither NF-kappa B-p50-DNA interactions nor the activation of NF-kappa B, instead they activate the transcription of proinflammatory genes and the release of reactive oxygen intermediates.

Many alternative treatment approaches, originating from Asia, are becoming increasingly popular in the Western hemisphere. Recently, an article published in a renowned journal reported that venom of apis mellifera (bee venom (BV)) and melittin mediate immune-modulating effects by blocking the activation of the transcription factor NF-kappaB. Such a modus operandi would corroborate the many claims of beneficial effects of BV treatment and give immediate credit to this form of therapy.

Aspects of the biology of hyaluronan, a largely neglected but extremely versatile molecule.

HA takes part in a surprisingly large number of biological processes such as embryogenesis, angiogenesis, cell motility, wound healing and cell adhesion. While substantial progress in HA research has indeed been made over the last years, many important questions have not yet been answered. One of the most pertinent questions awaiting an answer is the quest for functional differences of HA synthesized by the three HAS genes.

The anti-rheumatic gold salt aurothiomalate suppresses interleukin-1beta-induced hyaluronan accumulation by blocking HAS1 transcription and by acting as a COX-2 transcriptional repressor.

Gold compounds are among the oldest disease-modifying drugs and are still widely used today for treating rheumatoid arthritis. Despite decades of use, little is known about the mode of action of this class of drugs. Here we have demonstrated that aurothiomalate (AuTM) suppresses hyaluronan accumulation by blocking interleukin (IL)-1beta-induced hyaluronan synthase-1 transcription.

Short-term hyperthermia prevents activation of proinflammatory genes in fibroblast-like synoviocytes by blocking the activation of the transcription factor NF-kappaB.

Fibroblast-like synoviocytes (FLS) play a key role in the genesis of rheumatoid arthritis (RA). FLS are among the most versatile cells with the potential to activate an array of genes that are able to initiate and propagate inflammation in RA-affected joints. Controlling activation of FLS might hold the key to restraining inflammation in RA-affected joints.

Prostaglandin E2: a potent activator of hyaluronan synthase 1 in type-B-synoviocytes.

We demonstrated earlier that the gene HAS1 is inactive in resting type-B-synoviocytes but can be readily activated by a series of proinflammatory cytokines including IL-1beta. Here we show that in type-B-synoviocytes mRNA levels for the gene COX-2 increase more than 200-fold in response to IL-1beta treatment, whereas COX-1 mRNA levels remain virtually unchanged. We tested a series of eicosanoids and demonstrate that PGE(2) is a very potent activator of HAS1 in synoviocytes.

Expression of hyaluronan synthase genes in umbilical cord blood stem/progenitor cells.

Scientific progress reveals an ever-expanding role of hyaluronan (HA) in diverse biological functions. It has become increasingly clear that HA might also be essential for certain functions of stem cells. CD133+ cells isolated from umbilical cord blood (UCB) seem to represent an alternative to CD34+ cells as a source of transplantable haematopoietic progenitor cells.

Quinacrine but not chloroquine inhibits PMA induced upregulation of matrix metalloproteinases in leukocytes: quinacrine acts at the transcriptional level through a PLA2-independent mechanism.

Objective: Macrophages play an important role in rheumatoid arthritis (RA). RA is a disease characterized by the successive accumulation of leukocytes resulting in subsequent destruction of affected joints. Activation of matrix metalloproteinases (MMP) is essential for many physiological as well as many pathological events owing to the essential role of MMP in cell migration.

Cell-free plasma DNA: a marker for apoptosis during hemodialysis.

Background: We evaluated whether cell-free plasma DNA might be an appropriate marker for cell damage during hemodialysis (HD) and whether it correlated with annexin V expression and 7-amino-actinomycin D (7AAD) nuclear staining of blood leukocytes.

Methods: Circulating DNA, annexin V, and 7AAD were measured in HD patients before HD, 20 min after start of HD, and after HD had ended. Healthy volunteers provided control measurements.

Inhibition of human dendritic cell maturation and function by the novel immunosuppressant FK778.

Background: FK778, a derivative of the active leflunomide-metabolite, A77 1726, has been shown to be a powerful immunosuppressant in several transplantation models, particularly efficient in the prevention of chronic allograft rejection. However, the cellular and molecular mechanisms underlying these effects of FK778 have not been investigated yet in detail. Because dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) and are essential for the initiation of immune responses including acute and chronic allograft rejection, we investigated whether FK778 affects this particular cell type.

Adenovirus-mediated gene transfer of mutated IkappaB kinase and IkappaBalpha reveal NF-kappaB-dependent as well as NF-kappaB-independent pathways of HAS1 activation.

It has become increasingly clear that hyaluronan is more than the simple matrix molecule it was once thought to be but instead takes part in a multitude of biological functions. Three genes encode for hyaluronan synthases (HAS). We demonstrated earlier that HAS2 and HAS3 are constitutively activated in type-B synoviocytes (fibroblast-like synoviocytes) and, furthermore, that the only gene that readily responds to stimulation with a series of proinflammatory cytokines is HAS1.

Oxidized phospholipids negatively regulate dendritic cell maturation induced by TLRs and CD40.

Maturation of dendritic cells (DCs) induced by pathogen-derived signals via TLRs is a crucial step in the initiation of an adaptive immune response and therefore has to be well controlled. In this study, we demonstrate that oxidized phospholipids (ox-PLs), which are generated during infections, apoptosis, and tissue damage, interfere with DC activation, preventing their maturation. ox-PLs blocked TLR-3- and TLR-4-mediated induction of the costimulatory molecules CD40, CD80, CD83, and CD86, the cytokines IL-12 and TNF, as well as lymphocyte stimulatory capacity.

The malononitrilamide FK778 inhibits activation of NF-kappaB in human dendritic cells.

FK778, a derivative of the active leflunomide-metabolite, A77 1726, has been shown to be a powerful immunosuppressant in several transplantation models, particularly efficient in prevention of chronic allograft rejection. However, the cellular and molecular mechanisms underlying these effects of FK778 have not been investigated yet in detail. Because dendritic cells (DCs) are a crucial cell type in initiation of immune responses including chronic allograft rejection, we investigated whether FK778 affects this peculiar cell population.

Effects of leflunomide on hyaluronan synthases (HAS): NF-kappa B-independent suppression of IL-1-induced HAS1 transcription by leflunomide.

Despite evidence that points to unfettered hyaluronic acid (HA) production as a culprit in the progression of rheumatic disorders, little is known about differences in regulation and biological functions of the three hyaluronan synthase (HAS) genes. Testing the effects of drugs with proven anti-inflammatory effects could help to clarify biological functions of these genes. In this study, we demonstrate that leflunomide suppresses HA release in fibroblast-like synoviocytes (FLS) in a dose-dependent manner.

The active metabolite of leflunomide, A77 1726, interferes with dendritic cell function.

Leflunomide, a potent disease-modifying antirheumatic drug used in the treatment of rheumatoid arthritis (RA), exhibits anti-inflammatory, antiproliferative and immunosuppressive effects. Although most of the beneficial effects of leflunomide have been attributed to its antimetabolite activity, mainly in T cells, other targets accounting for its potency might still exist. Because of mounting evidence for a prominent role of dendritic cells (DCs) in the initiation and maintenance of the immune response in RA, we analyzed the effect of the active metabolite of leflunomide (A77 1726; LEF-M) on phenotype and function of human myleloid DCs at several stages in their life cycle.

Polyunsaturated fatty acids block dendritic cell activation and function independently of NF-kappaB activation.

Polyunsaturated fatty acids (PUFAs) modulate immune responses leading to clinically significant beneficial effects in a variety of inflammatory disorders. PUFA effects on T cells have been extensively studied, but their influence on human dendritic cells (DCs), which are the most potent antigen-presenting cells and play a key role in initiating immune responses, has not been elucidated so far. Here we show that PUFAs of the n-3 and n-6 series (arachidonic and eicosapentaenoic acid) affect human monocyte-derived DC differentiation and inhibit their activation by LPS, resulting in altered DC surface molecule expression and diminished cytokine secretion.