Mesenchymal stem cells from CD34−human umbilical cord blood

Characterization of human umbilical cord blood-derived mast cells using high-throughput expression profiling and next-generation knowledge discovery platforms

Mast cells (MCs) are tissue-resident innate immune cells that express the high-affinity receptor for immunoglobulin E and are responsible for host defense and an array of diseases related to immune system. We aimed in this study to characterize the pathways and gene signatures of human cord blood-derived MCs (hCBMCs) in comparison to cells originating from CD34- progenitors using next-generation knowledge discovery methods. CD34+ cells were isolated from human umbilical cord blood using magnetic activated cell sorting and differentiated into MCs with rhIL-6 and rhSCF supplementation for 6-8 weeks. The purity of hCBMCs was analyzed by flow cytometry exhibiting the surface markers CD117+CD34-CD45-CD23-FcεR1αdim. Total RNA from hCBMCs and CD34- cells were isolated and hybridized using microarray. Differentially expressed genes were analyzed using iPathway Guide and Pre-Ranked Gene Set Enrichment Analysis. Next-generation knowledge discovery platforms revealed MC-specific gene signatures and molecular pathways enriched in hCBMCs and pertain the immunological response repertoire.

Silencing NTPDase3 activity rehabilitates the osteogenic commitment of post-menopausal stem cell bone progenitors

BACKGROUND

Endogenously released adenine and uracil nucleotides favour the osteogenic commitment of bone marrow-derived mesenchymal stromal cells (BM-MSCs) through the activation of ATP-sensitive P2X7 and UDP-sensitive P2Y₆ receptors. Yet, these nucleotides have their osteogenic potential compromised in post-menopausal (Pm) women due to overexpression of nucleotide metabolizing enzymes, namely NTPDase3. This prompted us to investigate whether NTPDase3 gene silencing or inhibition of its enzymatic activity could rehabilitate the osteogenic potential of Pm BM-MSCs.

METHODS

MSCs were harvested from the bone marrow of Pm women (69 ± 2 years old) and younger female controls (22 ± 4 years old). The cells were allowed to grow for 35 days in an osteogenic-inducing medium in either the absence or the presence of NTPDase3 inhibitors (PSB 06126 and hN3-B3_s antibody); pre-treatment with a lentiviral short hairpin RNA (Lenti-shRNA) was used to silence the NTPDase3 gene expression. Immunofluorescence confocal microscopy was used to monitor protein cell densities. The osteogenic commitment of BM-MSCs was assessed by increases in the alkaline phosphatase (ALP) activity. The amount of the osteogenic transcription factor Osterix and the alizarin red-stained bone nodule formation. ATP was measured with the luciferin-luciferase bioluminescence assay. The kinetics of the extracellular ATP (100 µM) and UDP (100 µM) catabolism was assessed by HPLC RESULTS: The extracellular catabolism of ATP and UDP was faster in BM-MSCs from Pm women compared to younger females. The immunoreactivity against NTPDase3 increased 5.6-fold in BM-MSCs from Pm women vs. younger females. Selective inhibition or transient NTPDase3 gene silencing increased the extracellular accumulation of adenine and uracil nucleotides in cultured Pm BM-MSCs. Downregulation of NTPDase3 expression or activity rehabilitated the osteogenic commitment of Pm BM-MSCs measured as increases in ALP activity, Osterix protein cellular content and bone nodule formation; blockage of P2X7 and P2Y₆ purinoceptors prevented this effect.

CONCLUSIONS

Data suggest that NTPDase3 overexpression in BM-MSCs may be a clinical surrogate of the osteogenic differentiation impairment in Pm women. Thus, besides P2X7 and P2Y₆ receptors activation, targeting NTPDase3 may represent a novel therapeutic strategy to increase bone mass and reduce the osteoporotic risk of fractures in Pm women.

Chondrogenic differentiation of human umbilical cord blood-derived mesenchymal stem cells in vitro

Different therapeutic techniques have been developed for regeneration of articular cartilage injuries, but none has provided an optimal solution to their treatment. Human umbilical cord blood-mesenchymal Stem Cells (HUCB-MSCs) have been considered as promising alternative cell source for cartilage repair.

OBJECTIVES

Examining the success rate of MSCs isolation from HUCB as well as chondrogenic differentiation potential of HUCB-MSCs in vitro.

MATERIALS AND METHODS

32 UCB samples were collected, in addition to 5 bone marrow (BM) and 5 peripheral blood (PB) samples, taken as reference controls. Samples were used for mononuclear cells isolation from which MSCs were expanded under complete aseptic conditions, were verified morphologically and through the presence of CD44 and CD105, and absence of CD34.

RESULTS

Success rate of UCB-MSCs isolation was (25%), a rate that was lower than those of PB (40%) and BM (80%). Accordingly, certain input parameters have been recommended for successful MSCs isolation from UCB. On selecting samples in which recommended parameters were fulfilled, success rate was increased to 72%. This was together with providing optimal experiment conditions; mainly type of expansion medium, success rate reached 80%. Then, successfully expanded MSCs were subjected to chondrogenic differentiation by culturing in pelleted micromass system in presence of transforming growth factor beta-1 and chondrogenic medium devoid of fetal bovine serum to evaluate their ability to undergo chondrogenesis. Differentiation was verified microscopically using special stains, and proved by reverse transcriptase-polymerase chain reaction for expression of aggrecan and collagen II genes. In conclusion, in vitro differentiation into chondrocytes is possible from HUCB-MSCs.

Brown adipose tissue and novel therapeutic approaches to treat metabolic disorders

In humans, 2 functionally different types of adipose tissue coexist: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is involved in energy storage, whereas BAT is involved in energy expenditure. Increased amounts of WAT may contribute to the development of metabolic disorders, such as obesity-associated type 2 diabetes mellitus and cardiovascular diseases. In contrast, the thermogenic function of BAT allows high consumption of fatty acids because of the activity of uncoupling protein 1 in the internal mitochondrial membrane. Interestingly, obesity reduction and insulin sensitization have been achieved by BAT activation-regeneration in animal models. This review describes the origin, function, and differentiation mechanisms of BAT to identify new therapeutic strategies for the treatment of metabolic disorders related to obesity. On the basis of the animal studies, novel approaches for BAT regeneration combining stem cells from the adipose tissue with active components, such as melatonin, may have potential for the treatment of metabolic disorders in humans.

Stem cells of the respiratory system: from identification to differentiation into functional epithelium

We review recent progress in the stem cell biology of the respiratory system, and discuss its scientific and translational ramifications. Several studies have defined novel stem cells in postnatal lung and airways and implicated their roles in tissue homeostasis and repair. In addition, significant advances in the generation of respiratory epithelium from pluripotent stem cells (PSCs) now provide a novel and powerful platform for understanding lung development, modeling pulmonary diseases, and implementing drug screening. Finally, breakthroughs have been made in the generation of decellularized lung matrices that can serve as a scaffold for repopulation with respiratory cells derived from either postnatal or PSCs. These studies are a critical step forward towards the still distant goal of stem cell-based regenerative medicine for diseases of lung and airways.

Stem cells for reprogramming: could hUMSCs be a better choice?

Human umbilical cord mesenchymal stem cells (hUMSC) are primitive multipotent cells capable of differentiating into cells of different lineages. They can be an alternative source of pluripotent cells since they are ethically and regulatory approved, are easily obtained and have low immunogenicity compared to embryonic stem cells which are dogged with numerous controversies. hUMSC can be a great source for cell and transplantation therapy.

Human cord blood for the hypoxic-ischemic neonate

Autologous umbilical cord blood (UCB) is a possible, but unproven, treatment for acute neonatal brain damage. Mesenchymal stem cells (MSCs), which are present in UCB, are likely to be the treating cell type. UCB is effective in the treatment of neonatal rodent hypoxic-ischemic injury (HI) and other types of brain injury when the cells are delivered acutely. Other types of adult stem cells are similarly effective. However, several negative studies have been reported. The most likely mechanisms of action are participation in blood vessel regeneration, improvement of survival of intrinsic cells, perhaps via neurotrophic factors, or suppression of the release of inflammatory cells from the spleen. In the latter case, the splenic inflammatory cells released at the time of injury are thought to have an adverse effect on brain injury. The timing of the administration of the UCB with respect to the time of the injury appears to be the most important issue: the earlier the better. The risks of autologous administration of UCB are minimal. Current clinical trials with UCB are in progress, but there are no peer-reviewed reports as yet. A multicenter trial with specific inclusion criteria is needed.