Effects of seawater and freshwater challenges on the Gh/Igf system in the saline-tolerant blackchin tilapia (Sarotherodon melanotheron).

Prolactin (Prl) and growth hormone (Gh) as well as insulin-like growth factor 1 (Igf1) are involved in the physiological adaptation of fish to varying salinities. The Igfs have been also ascribed other physiological roles during development, growth, reproduction and immune regulation. However, the main emphasis in the investigation of osmoregulatory responses has been the endocrine, liver-derived Igf1 route and local regulation within the liver and osmoregulatory organs. Few studies have focused on the impact of salinity alterations on the Gh/Igf-system within the neuroendocrine and immune systems and particularly in a salinity-tolerant species, such as the blackchin tilapia Sarotherodon melanotheron. This species is tolerant to hypersalinity and saline variations, but it is confronted by severe climate changes in the Saloum inverse estuary. Here we investigated bidirectional effects of increased salinity followed by its decrease on the gene regulation of prl, gh, igf1, igf2, Gh receptor and the tumor-necrosis factor a. A mixed population of sexually mature 14-month old blackchin tilapia adapted to freshwater were first exposed to seawater for one week and then to fresh water for another week. Brain, pituitary, head kidney and spleen were excised at 4 h, 1, 2, 3 and 7 days after both exposures and revealed differential expression patterns. This investigation should give us a better understanding of the role of the Gh/Igf system within the neuroendocrine and immune organs and the impact of bidirectional saline challenges on fish osmoregulation in non-osmoregulatory organs, notably the complex orchestration of growth factors and cytokines.

CD40 Agonist Monoclonal Antibody-Mediated Hepatitis in TNF-Receptor 1 Gene Knockout Mice.

Tumor necrosis factor-alpha (TNF-α) plays an important role in liver inflammation. CD40-CD40 ligand (CD40-CD40L) is a key receptor-ligand signaling pair involved in the adaptive immune response and pathogenesis of autoimmune diseases. In mice, CD40 activation leads to sickness behavior syndrome (SBS) comprising weight loss, sleep disruption and depression, which can be blocked by administration of the TNF-inhibitor etanercept. In the present study, we assessed the extent of hepatic inflammation in mice devoid of the TNF-receptor 1 (TNFR1)-mediated signaling pathway. The TNFR1-depleted (TNFR1-/-) adult mice and their wild type littermates were given a single intra-peritoneal injection of CD40 agonist monoclonal antibody (mAb) or rat IgG2a isotope control. As described previously, TNFR1-/- mice were protected from SBS upon CD40 mAb treatment. Cd40, tnf and tnfr1 mRNA and Tnf-α peptide were increased in the liver of CD40 mAb-stimulated wild type mice. Serum alanine aminotransferase was elevated in both CD40-activated wild type and TNFR1-/- mice. TNFR1-/- mice showed much less intra-parenchymal infiltrates, hepatocellular necrosis, and perivascular clusters upon CD40 mAb activation than their wild type littermates. A gene expression microarray detected increased activity of metabolic and detoxification pathways and decreased activity of inflammatory pathways. We conclude that immune activation and development of liver inflammation in CD40L interactions depend on TNFR1-mediated signaling pathways and are counteracted by alterations in metabolic pathways.

Expression pattern of estrogen receptors α and ß and G-protein-coupled estrogen receptor 1 in the human testis.

Estrogen signaling is considered to play an important role in spermatogenesis, spermiogenesis and male fertility. Estrogens can act via the two nuclear estrogen receptors ESR1 (ERα) and ESR2 (ERß) or via the intracellular G-protein-coupled estrogen receptor 1 (GPER, formerly GPR30). Several reports on the localization and expression of all three receptors in the human testis have been published but are controversial particularly in case of ERα. Contrary to previous studies, we decided therefore to evaluate expression of all three receptors in the testis by a number of different methods and in comparison with MCF-7 cells. Using qPCR, we could show that mRNA expression of ERα is considerably lower and expression of ERß and GPER much higher in the testis than in MCF-7 cells. RT-PCR after laser-assisted microdissection of tubular and interstitial compartments from normal and Sertoli cell only syndrome testes plus in situ hybridization and immunohistochemical analyses of the same samples demonstrated that there is very low expression of ERα in germ cells and in single interstitial cells, very high expression of ERß in germ cells and Sertoli cells and high expression of GPER in interstitial cells and less in Sertoli cells.

Tenogenic differentiation of equine adipose-tissue-derived stem cells under the influence of tensile strain, growth differentiation factors and various oxygen tensions.

Mesenchymal stem cells have become extremely interesting for regenerative medicine and tissue engineering in the horse. Stem cell therapy has been proven to be a powerful and successful instrument, in particular for the healing of tendon lesions. We pre-differentiated equine adipose-tissue-derived stem cells (ASCs) in a collagen I gel scaffold by applying tensile strain, growth differentiation factors (GDFs) and various oxygen tensions in order to determine the optimal conditions for in vitro differentiation toward the tenogenic lineage. We compared the influence of 3% versus 21% oxygen tension, the use of GDF 5, GDF 6 and GDF 7 and the application of uniaxial tensile strain versus no mechanical stimulation on differentiation results as evaluated by cell morphology and by the expression of the tendon-relevant genes collagen I, collagen III, cartilage oligomeric matrix protein and scleraxis. The best results were obtained with an oxygen tension of 21%, tensile stimulation and supplementation with GDF 5 or GDF 7. This approach raises the hope that the in vivo application of pre-differentiated stem cells will improve healing and recovery time in comparison with treatment involving undifferentiated stem cells.

Light- and transmission-electron-microscopic investigations on distribution of CD44, connexin 43 and actin cytoskeleton during the foreign body reaction to a nanoparticular hydroxyapatite in mini-pigs.

Foreign body giant cells (FBGCs) are formed by fusion of mononucleated macrophages during the foreign body response to a nanoparticulate hydroxyapatite (HA) implanted in defects of mini-pig femura. The molecular mechanisms underlying the formation of FBGCs are still largely obscure. Here we propose connexin 43 (cx43) and CD44 as candidate molecules involved in the fusion process. Immunohistochemistry and ultrastructural immunogold labeling indicated that cx43 is present within the ruffled border of FBGCs and is the main component of gap junctions formed between fusing macrophages. CD44 was strongly expressed during clustering and fusion of mononucleated macrophages. FBGCs adhering apically at the implanted HA showed CD44 reactivity only along the basolateral aspects of the plasma membranes, while podosome formation was observed within the sealing zone and ruffled border. Taken together, these findings demonstrate that cx43 and CD44 are part of the fusion machinery responsible for the formation of FBGCs. Furthermore, the results of microfilament and cx43 labeling suggest a functional role for podosomes and hemi-channels in biomaterial degradation.

Isolation, culture and chondrogenic differentiation of canine adipose tissue- and bone marrow-derived mesenchymal stem cells--a comparative study.

In the dog, mesenchymal stem cells (MSCs) have been shown to reside in the bone marrow (bone marrow-derived mesenchymal stem cells: BM-MSCs) as well as in the adipose tissue (adipose tissue-derived stem cells: ADSCs). Potential application fields for these multipotent MSCs in small animal practice are joint diseases as MSCs of both sources have shown to possess chondrogenic differentiation ability. However, it is not clear whether the chondrogenic differentiation potential of cells of these two distinct tissues is truly equal. Therefore, we compared MSCs of both origins in this study in terms of their chondrogenic differentiation ability and suitability for clinical application. BM-MSCs harvested from the femoral neck and ADSCs from intra-abdominal fat tissue were examined for their morphology, population doubling time (PDT) and CD90 surface antigen expression. RT-PCR served to assess expression of pluripotency marker Oct4 and early differentiation marker genes. Chondrogenic differentiation ability was compared and validated using histochemistry, transmission electron microscopy (TEM) and quantitative RT-PCR. Both cell populations presented a highly similar morphology and marker expression in an undifferentiated stage except that freshly isolated ADSCs demonstrated a significantly faster PDT than BM-MSCs. In contrast, BM-MSCs revealed a morphological superior cartilage formation by the production of a more abundant and structured hyaline matrix and higher expression of lineage specific genes under the applied standard differentiation protocol. However, further investigations are necessary in order to find out if chondrogenic differentiation can be improved in canine ADSCs using different protocols and/or supplements.

Further insights into the characterization of equine adipose tissue-derived mesenchymal stem cells.

Adipose tissue-derived stem cells (ADSCs) represent a promising subpopulation of adult stem cells for tissue engineering applications in veterinary medicine. In this study we focused on the morphological and molecular biological properties of the ADSCs. The expression of stem cell markers Oct4, Nanog and the surface markers CD90 and CD105 were detected using RT-PCR. ADSCs showed a proliferative potential and were capable of adipogenic and osteogenic differentiation. Expression of Alkaline phosphatase (AP), phosphoprotein (SPP1), Runx2 and osteocalcin (OC) mRNA were positive in osteogenic lineages and peroxisome proliferator activated receptor (Pparγ2) mRNA was positive in adipogenic lineages. ADSCs show stem cell and surface marker profiles and differentiation characteristics that are similar to but distinct from other adult stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs). The availability of an easily accessible and reproducible cell source may greatly facilitate the development of stem cell based tissue engineering and therapies for regenerative equine medicine.

Effects of non-steroidal anti-inflammatory drugs on proliferation, differentiation and migration in equine mesenchymal stem cells.

In equine medicine, stem cell therapies for orthopaedic diseases are routinely accompanied by application of NSAIDs (non-steroidal anti-inflammatory drugs). Thus, it has to be analysed how NSAIDs actually affect the growth and differentiation potential of MSCs (mesenchymal stem cells) in vitro in order to predict the influence of NSAIDs such as phenylbutazone, meloxicam, celecoxib and flunixin on MSCs after grafting in vivo. The effects of NSAIDs were evaluated regarding cell viability and proliferation. Additionally, the multilineage differentiation capacity and cell migration was analysed. NSAIDs at lower concentrations (0.1-1 µM for celecoxib and meloxicam and 10-50 µM for flunixin) exert a positive effect on cell proliferation and migration, while at higher concentrations (10-200 µM for celecoxib and meloxicam and 100-1000 µM for flunixin and phenylbutazone), there is rather a negative influence. While there is hardly any influence on the adipogenic as well as on the chondrogenic MSC differentiation, the osteogenic differentiation potential, as demonstrated with the von Kossa staining, is significantly disturbed. Thus, it can be concluded that the effects of NSAIDs on MSCs are largely dependent on the concentrations used. Additionally, for some differentiation lineages, also the choice of NSAID is critical.