Ex vivo expansions of megakaryocytopoiesis from placental and umbilical cord blood CD34(+) cells in serum-free culture supplemented with proteoglycans extracted from the nasal cartilage of salmon heads and the nasal septum cartilage of whale

Clinical impact of glycans in platelet and megakaryocyte biology

Humans produce and remove 1011 platelets daily to maintain a steady-state platelet count. The tight regulation of platelet production and removal from the blood circulation prevents anomalies in both processes from resulting in reduced or increased platelet count, often associated with the risk of bleeding or overt thrombus formation, respectively. This review focuses on the role of glycans, also known as carbohydrates or oligosaccharides, including N- and O-glycans, proteoglycans, and glycosaminoglycans, in human and mouse platelet and megakaryocyte physiology. Based on recent clinical observations and mouse models, we focused on the pathologic aspects of glycan biosynthesis and degradation and their effects on platelet numbers and megakaryocyte function.

Characterization of Proteoglycan and Hyaluronan in Hot Water Extract from Salmon Cartilage

Salmon cartilage proteoglycan fractions have recently gained favor as ingredients of functional food and cosmetics. An optimal hot water method to extract proteoglycan from salmon cartilage has recently been developed. The extracted cartilage includes hyaluronan and collagen in addition to proteoglycan as counterparts that interact with each other. In this study, biochemical analyses and atomic force microscopical analysis revealed global molecular images of proteoglycan in the hot water extract. More than seventy percent of proteoglycans in this extract maintained their whole native structures. Hyaluronan purified from the hot water extract showed a distribution with high molecular weight similar to hyaluronan considered to be native hyaluronan in cartilage. The current data is evidence of the quality of this hot water cartilage extract.

Arachidonic acid and Docosahexanoic acid enhance platelet formation from human apheresis-derived CD34+ cells

An Aberration in megakaryopoiesis and thrombopoiesis, 2 important processes that maintain hemostasis, leads to thrombocytopenia. Though platelet transfusions are used to treat this condition, blood banks frequently face a shortage of platelets. Therefore, methods to generate platelets on a large scale are strongly desirable. However, to generate megakaryocytes (MKs) and platelets (PLTs) in numbers sufficient for clinical application, it is essential to understand the mechanism of platelet production and explore efficient strategies accordingly. We have earlier reported that the N-6 and N-3 poly-unsaturated fatty acids (PUFAs), Arachidonic acid (AA)/Docosahexanoic acid (DHA) have beneficial effect on the generation of MKs and PLTs from umbilical cord blood derived CD34⁺ cells. Here we tested if a similar effect is observed with peripheral blood derived CD34⁺ cells, which are more commonly used in transplantation settings. We found a significant enhancement in cell numbers, surface marker expression, cellular ploidy and expression of cytoskeletal components during PLT biogenesis in cultures exposed to media containing AA/DHA than control cultures that were not exposed to these PUFAs. The test cells engrafted more efficiently in NOD/SCID mice than control cells. AA/DHA appears to have enhanced MK/PLT generation through upregulation of the NOTCH and AKT pathways. Our data show that PUFAs could be valuable additives in the culture system for large scale production of platelets for clinical applications.

Proteoglycan from salmon nasal cartridge [corrected] promotes in vitro wound healing of fibroblast monolayers via the CD44 receptor

Proteoglycans (PGs) are involved in various cellular functions including cell growth, adhesion, and differentiation; however, their physiological roles are not fully understood. In this study, we examined the effect of PG purified from salmon nasal cartilage (SNC-PG) on wound closure using tissue-cultured cell monolayers, an in vitro wound-healing assay. The results indicated that SNC-PG significantly promoted wound closure in NIH/3T3 cell monolayers by stimulating both cell proliferation and cell migration. SNC-PG was effective in concentrations from 0.1 to 10μg/ml, but showed much less effect at higher concentrations (100-1000μg/ml). The effect of SNC-PG was abolished by chondroitinase ABC, indicating that chondroitin sulfates (CSs), a major component of glycosaminoglycans (GAGs) in SNC-PG, are crucial for the SNC-PG effect. Furthermore, chondroitin 6-sulfate (C-6-S), a major CS of SNC-PG GAGs, could partially reproduce the SNC-PG effect and partially inhibit the binding of SNC-PG to cells, suggesting that SNC-PG exerts its effect through an interaction between the GAGs in SNC-PG and the cell surface. Neutralization by anti-CD44 antibodies or CD44 knockdown abolished SNC-PG binding to the cells and the SNC-PG effect on wound closure. These results suggest that interactions between CS-rich GAG-chains of SNC-PG and CD44 on the cell surface are responsible for the SNC-PG effect on wound closure.

Biochemical and atomic force microscopic characterization of salmon nasal cartilage proteoglycan

Biological activities of salmon nasal cartilage proteoglycan fractions are known, however, structural information is lacking. Recently, the major proteoglycan of this cartilage was identified as aggrecan. In this study, global molecular images and glycosaminoglycan structure of salmon nasal cartilage aggrecan purified from 4M guanidine hydrochloride extract were analyzed using HPLCs and atomic force microscopy with bovine tracheal cartilage aggrecan as a control. The estimated numbers of sulfates per disaccharide unit of chondroitin sulfate chains of salmon and bovine aggrecans were similar (approximately 0.85). However, the disaccharide composition showed a higher proportion of chondroitin 6-sulfate units in salmon aggrecan, 60%, compared to 40% in bovine. Gel filtration HPLC and monosaccharide analysis showed the salmon aggrecan had a lower number (approximately one-third), but 1.5-3.3 times longer chondroitin sulfate chains than the bovine aggrecan. Atomic force microscopic molecular images of aggrecan supported the images predicted by biochemical analyses.

Three-stage ex vivo expansion of high-ploidy megakaryocytic cells: toward large-scale platelet production

Hematopoietic stem and progenitor cells (HSPCs) have been cultured using a wide variety of cytokines to promote differentiation into megakaryocytic cells (Mks), the precursors to platelets. Greater Mk DNA content, or ploidy, has been correlated with increased platelet release. Gradients of pH, pO2, and signaling factors regulate megakaryopoiesis in the bone marrow niche. In this study, we demonstrate that a 3-phase culture process with increasing pH and pO2 and different cytokine cocktails greatly increases megakaryocyte production. CD34(+) HSPCs were first cultured at 5% O2 and pH 7.2 with a cytokine cocktail previously shown to promote Mk progenitor production. At day 5, cells were shifted to 20% O2 and pH 7.4 and maintained in 1 of 17 cytokine cocktails identified using a 2(4) factorial design of experiments method to evaluate the effects of interleukin (IL)-3, IL-6, IL-9, and high- or low-dose stem cell factor (SCF), in conjunction with thrombopoietin (Tpo) and IL-11, on expansion of mature Mks from progenitors. The combination of Tpo, high-dose SCF, IL-3, IL-9, and IL-11 best promoted Mk expansion. IL-3 greatly increased total cell fold expansion, but this was partially offset by lower Mk purity. IL-9 promoted CD41 and CD42b expression. High-dose (100 ng/mL) SCF increased Mk production and ploidy. Different commercial media and IL-3 sources substantially impacted differentiation, and X-VIVO 10 serum-free media best supported mature Mk expansion. Shifting from pH 7.4 to pH 7.6 at day 7 increased Mk production by 30%. Treatment with nicotinamide at day 7 or day 8 more than doubled the fraction of high-ploidy (>4N) Mks. Ultimately, the 3-phase culture system gave rise to 44.5±8.1 Mks and 8.5±3.1 high-ploidy Mks per input HSPC. Further optimization was required to improve platelet production. Using Iscove's modified Dulbecco's medium (IMDM)+20% BSA, insulin and transferin (BIT) 9500 Serum Substitute greatly improved the frequency and quality of Mk proplatelet extensions without affecting Mk expansion, commitment, or polyploidization in the 3-phase process. Mks cultured in IMDM+20% BIT 9500 gave rise to platelets with functional activity similar to that of fresh platelets from normal donors, as evidenced by basal tubulin distribution and the expression of surface markers and spreading in response to platelet agonists.

Polyunsaturated fatty acids confer cryoresistance on megakaryocytes generated from cord blood and also enhance megakaryocyte production from cryopreserved cord blood cells

BACKGROUND AIMS

Previous data have shown that the addition of docosahexanoic acid (DHA)/arachidonic acid (AA) has a beneficial effect on cytokine-mediated in vitro generation of megakaryocytes (MK) from umbilical cord blood (UCB).Cryopreservation forms an inherent part of UCB banking and MK progenitors are known to be very sensitive to the stresses of freezing. It is therefore imperative to generate functional cells from cryopreserved cells, and the generated cells need to be cryopreserved until used. In the present study, cryopreservation of ex vivo-expanded MK as well as MK generation from cryopreserved UCB samples was investigated.

METHODS

MK generated with or without DHA/AA were cryopreserved in freezing medium containing 10% dimethyl sulfoxide (DMSO). Freezing efficacy was tested by quantitating MK after revival. Cryopreserved CD34(+) cells were cultured with stem cell factor (SCF) and thrombopoietin (TPO), in the presence and absence of DHA/AA for 10 days, and then quantitated for MK. Results. We observed a 1.5-3-fold increase in MK numbers, their progenitor content and their expression of phenotypic markers and MK-related transcription factors. DHA/AA sets showed a 2-5-fold improved engraftment in NOD/SCID mice. These data showed that the beneficial effect of DHA/AA obtained during MK expansion was not altered after freezing stress. The enhancement in MK generation obtained from fresh cord blood (CB) cells was reproduced with comparable efficiency when we used cryopreserved CB samples.

CONCLUSIONS

Taken together, our data suggest that in vitro-generated DHA/AA MK survive cryoinjuries in a functionally better state. DHA/AA support a more efficient generation of MK from cryopreserved UCB.

Proteoglycans regulate the chemotaxis of dendritic cells derived from human peripheral blood monocytes

Dendritic cells (DCs) are a type of antigen-presenting cell which play an essential role in the immune system. The transition from immature DC (iDCs) to mature DCs (mDCs) requires appropriate maturation stimuli, such as pro-inflammatory cytokines or pathogen-derived components. Proteoglycans (PGs), which are composed of core proteins and the glycosaminoglycans that bind to them, are one of the main components of the extracellular matrix around pathogens such as bacteria. This study investigated the effects of PG extracted from the nasal septum cartilage of whale (W-PG) on the maturation of DCs derived from human peripheral blood monocytes. iDCs were prepared from human monocytes using granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The iDCs were stimulated by W-PG alone. In another type of experiment, the iDCs were stimulated by MIX (tumor necrosis factor-alpha (TNF-alpha), IL-1beta, IL-6 and prostaglandin E(2) (PGE(2))) or a combination of MIX plus W-PG. The stimulation of W-PG alone did not induce the phenotypic maturation from iDCs. However, W-PG promoted the up-regulation of chemokine receptor CCR7-surface expression and the chemotactic responsiveness to CCR7 ligand macrophage inflammatory protein-3beta on MIX-stimulated mDCs although W-PG did not influence matrix metalloproteinase-9 activity which is an important factor in DC migration through the extracellular matrix. The findings that W-PG can selectively regulate the chemotactic activity of DCs in vitro under inflammatory conditions therefore indicate that the interaction of PGs with immune cells including DCs plays an important role in the immune response under the milieu of innate immunity.

Identification of proteoglycan from salmon nasal cartilage

There has been no structural information about the core protein of salmon nasal cartilage proteoglycan although its physiological activities have been investigated. Internal amino acid sequencing using nano-LC/MS/MS revealed that the salmon proteoglycan was aggrecan. Primer walk sequencing based on the amino acid information determined that the salmon aggrecan cDNA is comprised of 4207bp nucleotides predicted to encode 1324 amino acids with a molecular mass of 143,276. It exhibited significant similarities to predicted pufferfish aggrecan, zebrafish similar to aggrecan, zebrafish aggrecan, bovine aggrecan and human aggrecan isoform 2 precursor; whose amino acid identities were 56%, 55%, 49%, 31% and 30%, respectively. Salmon cartilage aggrecan had globular domains G1, G2 and G3 as in mammalian aggrecans. Neither the putative keratan sulfate attachment domain enriched with serine, glutamic acid and proline, nor the putative chondroitin sulfate attachment domain with repeating amino acid sequence containing serine-glycine, found in mammalian aggrecans were observed in salmon, however, random serine-glycine (or glycine-serine) sequences predicted to the sugar chain attachment sites were observed. Based on cDNA analysis and amino acid analysis after β-elimination, the ratio of serine attached to sugar chains was calculated to be approximately 37.7% of total serine, that is, 46 of 123 serine residues.

Effects of proteoglycan extracted from nasal cartilage of salmon heads on maturation of dendritic cells derived from human peripheral blood monocytes

Dendritic cells (DCs) play an essential role in the immune system. The transition from immature DC (iDCs) to mature DCs (mDCs) requires appropriate stimuli such as pro-inflammatory cytokines. Proteoglycans (PGs) are one of the main components of extracellular matrix, and some types of PGs are known to induce maturation of murine DCs. Recent studies have investigated the potential benefits of PG from nasal cartilage of salmon head (S-PG). This study investigated the effects of S-PG on maturation of human monocyte-derived DCs. iDCs were prepared from human monocytes using the appropriate cytokines and then stimulated by S-PG alone. In another experiment, iDCs were stimulated by a combination of pro-inflammatory cytokines (MIX) plus S-PG. Although the stimulation of S-PG alone did not induce phenotypic maturation from iDCs, CD40 expression on DCs stimulated by S-PG alone was lower than that of iDCs. In contrast, the phenotypic and functional characteristics of DCs stimulated by MIX+S-PG were similar to those of DCs stimulated by MIX alone. As a result, S-PG did not demonstrate a significant effect with regard to maturation of human monocyte-derived DCs.

Enhanced generation of megakaryocytes from umbilical cord blood-derived CD34(+) cells expanded in the presence of two nutraceuticals, docosahexanoic acid and arachidonic acid, as supplements to the cytokine-containing medium

BACKGROUND AIMS

Ex vivo generation of megakaryocytes (MK) from hematopoietic stem cells (HSC) is important for both basic research, to understand the mechanism of platelet biogenesis, and clinical infusions, for rapid platelet recovery in thrombocytopenic patients. We investigated the role of two nutraceuticals, docosahexanoic acid (DHA) and arachidonic acid (AA), in the in vitro generation of MK.

METHODS

Umbilical cord blood (UCB)-derived CD34+cells were cultured with stem cell factor (SCF) and thrombopoietin (TPO) in the presence (test) or absence (control) of the two additives. On day 10, MK and platelets generated were quantitated by morphologic, phenotypic and functional assays.

RESULTS

The cell yield of MK and platelet numbers were significantly higher in test compared with control cells. Phenotypic analyzes and gene expression profiles confirmed these findings. Functional properties, such as colony-forming unit (CFU)-MK formation, chemotaxis and platelet activation, were found to be enhanced in cells cultured with nutraceuticals. The engraftment potential of ex vivo-expanded cells was studied in NOD/SCID mice. Mice that received MK cultured in the presence of DHA/AA engrafted better. There was a reduction in apoptosis and total reactive oxygen species (ROS) levels in the CD41(+) compartment of the test compared with control sets. The data suggest that these compounds probably exert their beneficial effect by modulating apoptotic and redox pathways.

CONCLUSIONS

Use of nutraceuticals like DHA and AA may prove to be a useful strategy for efficient generation of MK and platelets from cord blood cells, for future use in clinics and basic research.