BackgroundMesenchymal stromal cells (MSCs) are attractive for cell-based therapies ranging from regenerative medicine and tissue engineering to immunomodulation. However, clinical efficacy is variable and it is unclear how the phenotypes defining bone marrow (BM)-derived MSCs as well as donor characteristics affect their functional properties.MethodsBM-MSCs were isolated from 53 (25 female, 28 male; age: 13 to 80 years) donors and analyzed by: (1) phenotype using flow cytometry and cell size measurement; (2) in vitro growth kinetics using population doubling time; (3) colony formation capacity and telomerase activity; and (4) function by in vitro differentiation capacity, suppression of T cell proliferation, cytokines and trophic factors secretion, and hormone and growth factor receptor expression. Additionally, expression of Oct4, Nanog, Prdm14 and SOX2 mRNA was compared to pluripotent stem cells.ResultsBM-MSCs from younger donors showed increased expression of MCAM, VCAM-1, ALCAM, PDGFRβ, PDL-1, Thy1 and CD71, and led to lower IL-6 production when co-cultured with activated T cells. Female BM-MSCs showed increased expression of IFN-γR1 and IL-6β, and were more potent in T cell proliferation suppression. High-clonogenic BM-MSCs were smaller, divided more rapidly and were more frequent in BM-MSC preparations from younger female donors. CD10, β1integrin, HCAM, CD71, VCAM-1, IFN-γR1, MCAM, ALCAM, LNGFR and HLA ABC were correlated to BM-MSC preparations with high clonogenic potential and expression of IFN-γR1, MCAM and HLA ABC was associated with rapid growth of BM-MSCs. The mesodermal differentiation capacity of BM-MSCs was unaffected by donor age or gender but was affected by phenotype (CD10, IFN-γR1, GD2). BM-MSCs from female and male donors expressed androgen receptor and FGFR3, and secreted VEGF-A, HGF, LIF, Angiopoietin-1, basic fibroblast growth factor (bFGF) and NGFB. HGF secretion correlated negatively to the expression of CD71, CD140b and Galectin 1. The expression of Oct4, Nanog and Prdm14 mRNA in BM-MSCs was much lower compared to pluripotent stem cells and was not related to donor age or gender. Prdm14 mRNA expression correlated positively to the clonogenic potential of BM-MSCs.ConclusionsBy identifying donor-related effects and assigning phenotypes of BM-MSC preparations to functional properties, we provide useful tools for assay development and production for clinical applications of BM-MSC preparations.

The anti-inflammatory drug licofelone [ϭML3000; 2-[6-(4-chlorophenyl)-2,2-dimethyl-7-phenyl-2,3-dihydro-1H-pyrrolizin-5-yl] acetic acid], currently undergoing phase III trials for osteoarthritis, inhibits the prostaglandin (PG) and leukotriene biosynthetic pathway. Licofelone was reported to suppress the formation of PGE 2 in various cell-based test systems, but the underlying molecular mechanisms are not entirely clear. Here, we examined the direct interference of licofelone with enzymes participating in PGE 2 biosynthesis, that is, cyclooxygenase (COX)-1 and COX-2 as well as microsomal PGE 2 synthase (mPGES)-1. Licofelone concentration-dependently inhibited isolated COX-1 (IC 50 ϭ 0.8 M), whereas isolated COX-2 was less affected (IC 50 Ͼ 30 M). However, licofelone efficiently blocked the conversion of PGH 2 to PGE 2 mediated by mPGES-1 (IC 50 ϭ 6 M) derived from microsomes of interleukin-1␤-treated A549 cells, being about equipotent to 3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2,2-dimethylpropanoic acid (MK-886), a well recognized mPGES-1 inhibitor. In intact interleukin-1␤-treated A549 cells, licofelone potently (IC 50 Ͻ 1 M) blocked formation of PGE 2 in response to calcimycin (A23187) plus exogenous arachidonic acid, but the concomitant generation of 6-keto PGF 1␣ , used as a biomarker for COX-2 activity, was not inhibited. We conclude that licofelone suppresses inflammatory PGE 2 formation preferentially by inhibiting mPGES-1 at concentrations that do not affect COX-2, implying an attractive and thus far unique molecular pharmacological dynamics as inhibitor of COX-1, the 5-lipoxygenase pathway, and of mPGES-1.Prostaglandins (PGs) and leukotrienes are powerful bioactive lipid mediators that are involved not only in numerous homeostatic biological functions but also in inflammation (Funk, 2001). The biosynthesis of PGs is initialized by COX isoenzymes, namely, COX-1, a constitutively expressed enzyme in numerous cell types thought to provide PGs mainly for physiological functions; and COX-2, an inducible isoform in inflammatory cells, primarily producing PGs relevant for inflammation, fever, and pain (Hawkey, 1999). After conversion of arachidonic acid to PGH 2 by COX enzymes, PGH 2 is subsequently isomerized by three different PGE 2 synthases to PGE 2 . Whereas the cytosolic PGE 2 synthase (cPGES) and the membrane-bound PGE 2 synthase (mPGES)-2 are constitutive enzymes, the mPGES-1 is an inducible isoform (Samuelsson et al., 2007). Cotransfection experiments of COX-1/2 with PGES isoenzymes imply that select molecular interactions between COX and PGES isoenzymes cause preferential functional coupling (Murakami et al., 2000;Samuelsson et al., 2007). Thus, cPGES uses PGH 2 produced by COX-1, whereas mPGES-1 receives PGH 2 from COX-2. PGE 2 plays a major role in the pathophysiology of inflammation, pain, and pyresis, but it also regulates physiological functions in the gastrointestinal tract, the kidney, and in the immune and nervous system (Smith, 1989). The nonsteroidal anti-inflamm...

5-Lipoxygenase initiates the biosynthesis of leukotrienes, lipid mediators involved in normal host defense and in inflammatory and allergic disorders. Despite an obvious gender bias in leukotriene-related diseases (e.g., asthma), gender aspects have been neglected in studies on leukotrienes and 5-lipoxygenase. Here, we show that leukotriene formation in stimulated whole blood or neutrophils from males is substantially lower compared with females, accompanied by changed 5-lipoxygenase trafficking. This is due to gender-specific differential activation of extracellular signal-regulated kinases (ERKs). The differences are directly related to variant male/female testosterone plus 5␣-dihydrotestosterone levels, and addition of 5␣-dihydrotestosterone to female blood or neutrophils reduced the high (female) LT biosynthesis capacity to low (male) levels. In conclusion, regulation of ERKs and leukotriene formation by androgens constitutes a molecular basis for gender differences in the inflammatory response, and in inflammatory diseases such as asthma. 5-lipoxygenase ͉ arachidonic acid

Microglia, the resident macrophages of the brain, typically react to injuries or chronic diseases with proliferation and expression of differentiated features, such as production of cytokines associated with inflammatory events. Regulation and control of microglial cytokine expression, therefore, is a major focus of scientific interest. It has been shown that GMCSF and Il‐3 are potent mitogens for microglia. Moreover, Il‐3 and other cytokines are products of microglia. It is shown here that interleukin‐1 (Il‐1) as well as tumor necrosis factor (TNFα) increased microglial proliferation in mixed astrocyte‐microglial cultures but had no mitogenic effects on isolated microglia. © Wiley‐Liss, Inc. Lipopolysaccharide (LPS), the bacterial endotoxin, irreversibly inhibited microglial cell division in both mixed astrocyte‐microglial cultures and in isolated microglial cultures. By contrast, the corticosteroids hydrocortisone and aldosterone and the synthetic glucocorticoid dexamethasone reversibly inhibited microglial proliferation. They also antagonized the stimulatory effects of Il‐3 and granulocyte macrophage colony‐stimulating factor (GMCSF). Estradiol and progesterone had no significant effects on mixed cultures but inhibited microglial proliferation in isolated cultures. Conditioned media from mixed cultures, isolated cultures, from the WEHI‐2B cell line, or from fresh (serum‐supplemented) media stimulated microglial proliferation to various extents. In summary, cytokine‐mediated microglial proliferation can be down‐regulated by a variety of steroid hormones. Along with their unimpaired access to brain cells in general, corticosteroids likely maintain an inhibitory tonus on microglial proliferation. It is hypothesized that this inhibition is overcome locally and temporally in brain injury and repair. © Wiley‐Liss, Inc.

Primary rat astrocyte cultures were used to isolate a macrophage population that does not adhere to the confluent glial cells. The cells multiplied vigorously in coculture with astrocytes during the 14 d culture period, provided that functionally active lipopolysaccharide (LPS) was either absent or present in very low concentrations. Based on morphological, immunocytochemical, and pharmacological data, it was concluded that the isolated cells were microglia, the resident macrophages of the brain. The findings characterized them as a distinct cell population that shares features both of peritoneal macrophages and of astroglial cells. Like peritoneal macrophages, the isolated cells were able to phagocytize as shown by their ingestion of latex beads and uptake of L-leucyl methylester. Furthermore, they were immunocytochemically stainable by a specific monoclonal antibody (ED 1) against a macrophage-specific antigen (Dijkstra et al., 1985). They also synthesized prostaglandin E2 (PGE2) and secreted interleukin 1 (IL-1) upon stimulation with LPS. Upon stimulation with the ionophore A23187, PGD2, the predominant prostaglandin of the brain, was the major PG metabolite released by these cells. In contrast to peritoneal macrophages, microglial cells were able to multiply. Proliferation of microglial cells in coculture with astrocytes was suppressed when 2 ng LPS/ml or higher concentrations were added to astroglial culture media. These astrocyte cultures, which contained approximately 1% microglia, were used to investigate the influence of LPS on prostaglandin and IL-1 secretion in order to compare astroglial and microglial features. Increasing LPS concentrations induced increased PGE2 secretion, whereas PGD2 secretion was essentially unaffected by LPS. The critical influence of LPS contaminations in most of the commercially available animal sera used for astrocyte cultures on cellular composition in general and on metabolism of hormones and growth factors in particular is discussed.