Human mesenchymal stem cells (hMSCs) are an attractive choice for a variety of cellular therapies. hMSCs can be isolated from many different tissues and possess unique mitochondrial properties that can be used to determine their differentiation potential. Mitochondrial properties may possibly be used as a quality measure of hMSC-based products. Accordingly, the present work focuses on the mitochondrial function of hMSCs from umbilical cord blood (UCBMSC) cells and bone marrow cells from donors younger than 18 years of age (BMMSC <18) and those more than 50 years of age (BMMSC >50). Changes of ultrastructure and energy metabolism during osteogenic differentiation in all hMSC types were studied in detail. Results show that despite similar surface antigen characteristics, the UCBMSCs had smaller cell surface area and possessed more abundant rough endoplasmic reticulum than BMMSC >50. BMMSC <18 were morphologically more UCBMSC-like. UCBMSC showed dramatically higher mitochondrial-to-cytoplasm area ratio and elevated superoxide and manganese superoxide dismutase (MnSOD) levels as compared with BMMSC >50 and BMMSC <18. All hMSCs types showed changes indicative of mitochondrial activation after 2 weeks of osteogenic differentiation, and the increase in mitochondrial-to-cytoplasm area ratio appears to be one of the first steps in the differentiation process. However, BMMSC >50 showed a lower level of mitochondrial maturation and differentiation capacity. UCBMSCs and BMMSCs also showed a different pattern of exocytosed proteins and glycoproteoglycansins. These results indicate that hMSCs with similar cell surface antigen expression have different mitochondrial and functional properties, suggesting different maturation levels and other significant biological variations of the hMSCs. Therefore, it appears that mitochondrial analysis presents useful characterization criteria for hMSCs intended for clinical use.

Human mesenchymal stem cells (hMSCs) display immunosuppressive properties in vitro and the potential has also been transferred successfully to clinical trials for treatment of autoimmune diseases. OX-2 (CD200), a member of the immunoglobulin superfamily, is widely expressed in several tissues and has recently been found from hMSCs. The CD200 receptor (CD200R) occurs only in myeloid-lineage cells. The CD200-CD200R is involved in down-regulation of several immune cells, especially macrophages. The present study on 20 hMSC lines shows that the CD200 expression pattern varied from high (CD200Hi) to medium (CD200Me) and low (CD200Lo) in bone marrow-derived mesenchymal stem cell (BMMSC) lines, whereas umbilical cord blood derived mesenchymal stem cells (UCBMSCs) were constantly negative for CD200. The role of the CD200-CD200R axis in BMMSCs mediated immunosuppression was studied using THP-1 human macrophages. Interestingly, hMSCs showed greater inhibition of TNF-α secretion in co-cultures with IFN-γ primed THP-1 macrophages when compared to LPS activated cells. The ability of CD200Hi BMMSCs to suppress TNF-α secretion from IFN-γ stimulated THP-1 macrophages was significantly greater when compared to CD200Lo whereas UCBMSCs did not significantly reduce TNF-α secretion. The interference of CD200 binding to the CD200R by anti-CD200 antibody weakened the capability of BMMSCs to inhibit TNF-α secretion from IFN-γ activated THP-1 macrophages. This study clearly demonstrated that the efficiency of BMMSCs to suppress TNF-α secretion of THP-1 macrophages was dependent on the type of stimulus. Moreover, the CD200-CD200r axis could have a previously unidentified role in the BMMSC mediated immunosuppression.

Periodontitis and Chlamydia pneumoniae infection are independent risk factors for cardiovascular diseases. The aim of this study was to investigate the effect of C. pneumoniae and Aggregatibacter actinomycetemcomitans infection on hepatic inflammation and lipid homeostasis of apolipoprotein E-deficient mice. Mice were infected with viable C. pneumoniae intranasally three times for chronic infection or once for acute infection. Viable A. actinomycetemcomitans was administered 10 times intravenously alone or in concert with C. pneumoniae. Hepatic alterations were assessed by histochemistry, lipid quantification, and fatty acid profile analysis. The RNA expression levels and the presence of pathogens in the livers and lungs were detected by quantitative real-time PCR. Both pathogens were detected in the livers of the infected animals. Chronic C. pneumoniae infection induced marked changes in hepatic lipid homeostasis. A. actinomycetemcomitans infection resulted in inflammatory cell infiltration into the liver, accompanied by elevated hepatic RNA expression levels of inflammation-related genes and higher serum amyloid A and lipopolysaccharide concentrations. Our results indicate that proatherogenic pathogens infect the liver, causing proinflammatory alterations and lipid disturbances. This infection may maintain chronic systemic inflammation attributable to atherogenesis.

We identified in a yeast two-hybrid screen the EF-hand Ca2+-binding protein Cab45 as an interaction partner of Munc18b. Although the full-length Cab45 resides in Golgi lumen, we characterize a cytosolic splice variant, Cab45b, expressed in pancreatic acini. Cab45b is shown to bind 45Ca2+, and, of its three EF-hand motifs, EF-hand 2 is demonstrated to be crucial for the ion binding. Cab45b is shown to interact with Munc18b in an in vitro assay, and this interaction is enhanced in the presence of Ca2+. In this assay, Cab45b also binds the Munc18a isoform in a Ca2+-dependent manner. The endogenous Cab45b in rat acini coimmunoprecipitates with Munc18b, syntaxin 2, and syntaxin 3, soluble N-ethylmaleimide-sensitive factor attachment protein receptors with key roles in the Ca2+-triggered zymogen secretion. Furthermore, we show that Munc18b bound to syntaxin 3 recruits Cab45b onto the plasma membrane. Importantly, antibodies against Cab45b are shown to inhibit in a specific and dose-dependent manner the Ca2+-induced amylase release from streptolysin-O–permeabilized acini. The present study identifies Cab45b as a novel protein factor involved in the exocytosis of zymogens by pancreatic acini.

Atherosclerosis is a chronic disease of the arteries whose development involves a local inflammatory response characterized by the activation of different cells such as macrophages, T-lymphocytes, smooth muscle cells (SMCs) and endothelial cells (ECs). This review will summarize recent evidence for a modulatory role of the nuclear receptor ROR-α in cardiovascular disease.