Serology and molecular genetic analysis of two unrelated individuals with the same novel CisAB blood type.

OBJECTIVE: This study aims to report two unrelated individuals with the same novel CisAB blood type and confirm this rare blood type using a comprehensive approach that combines serological and molecular biology techniques. METHODS: Peripheral blood samples were collected from two patients and their family members. ABO blood typing and antibody detection were performed using conventional tube methods. Molecular biology techniques were employed to amplify and sequence the 6th and 7th exons of the ABO gene, with reference to gene mutation databases provided by NCBI and ISBT. RESULTS: The genotypes of the two unrelated individuals were identical and were confirmed as a new genotype through ISBT gene database comparison. Serological testing results showed different antigen reaction patterns, especially in terms of reverse typing. Gene sequencing identified a series of mutation points, and both unrelated individuals and one of their daughters had mutations at 297 A>G, 526 C>G, 657 C>T, 703 G>A, 803 G>C, and 930 G>A. According to the comprehensive results from The Blood Group Antigen Gene Mutation Database provided by NCBI, the genotype was determined as Bw37. However, based on the results from Names for ABO (ISBT 001) blood group alleles v1.1 171023, the sequencing results indicated a novel mutation combination not found in the ISBT database. Considering the serological reactions of all three individuals, the final determination was CisAB. CONCLUSIONS: This study confirmed the novel CisAB blood type in two individuals through the comprehensive application of serology and molecular biology techniques. The identified gene mutation points were not recorded in known databases, emphasizing the uniqueness of CisAB blood types. This research provides important insights into the genetic basis of ABO subtypes and the characteristics of CisAB blood types, and the relevant results have been submitted to the ISBT website for further research.

Molecular Genetic Analysis of Para-Bombay Phenotype in Chinese: Identification of a Novel FUT1 Allele.

BACKGROUND: The goal was to identify a novel FUT1 allele and to study serologic and gene feature of the para-Bombay blood type of one expectant mother in Xinjiang, China. METHODS: ABO and Lewis groups were recognized by standard serologic techniques in an ABO typing discrepancy specimen from one person at the Tianjin Blood Center. DNA (deoxyribonucleic acid) was collected and polymerase chain reactions with sequence-specific primers (PCR-SSP) were performed to sequence exons 6 and 7 of ABO gene, exon 4 of FUT1 gene, and exon 2 of FUT2. PCR products were sequenced to identify ABO groups and the variation sites. The genotype was determined by family study. RESULTS: In our laboratory testing, erythrocytes from the proposita did not react with anti-A and anti-B reagents. B antigen was discovered only after adsorption and elution. Red cells were nonreactive with monoclonal anti-H. The sera of the proposita contained anti-A and were weakly agglutinated by B cells. The hybrid 902 A>G mutation was detected in the proposita's father and mother. The proposita has the same mutation 902 A>G, which was conjectured as homozygosity for 902 A>G. CONCLUSIONS: One novel mutation of FUT1 gene was observed in our laboratory. It has never been reported previously. The para-Bombay phenotype in the proposita originating from Xinjiang (China) results from homozygosity for FUT1 902 A>G, together with 357 C>T of FUT2.

Development of Icephilic ACTIVE Glycopeptides for Cryopreservation of Human Erythrocytes.

Ice formation and recrystallization exert severe impairments to cellular cryopreservation. In light of cell-damaging washing procedures in the current glycerol approach, many researches have been devoted to the development of biocompatible cryoprotectants for optimal bioprotection of human erythrocytes. Herein, we develop a novel ACTIVE glycopeptide of saccharide-grafted ε-poly(L-lysine), that can be credited with adsorption on membrane surfaces, cryopreservation with trehalose, and icephilicity for validity of human erythrocytes. Then, by Borch reductive amination or amidation, glucose, lactose, maltose, maltotriose, or trehalose was tethered to ε-polylysine. The synthesized ACTIVE glycopeptides with intrinsic icephilicity could localize on the membrane surface of human erythrocytes and improve cryopreservation with trehalose, so that remarkable post-thaw cryosurvival of human erythrocytes was achieved with a slight variation in cell morphology and functions. Human erythrocytes (∼50% hematocrit) in cryostores could maintain high cryosurvival above 74%, even after plunged in liquid nitrogen for 6 months. Analyses of differential scanning calorimetry, Raman spectroscopy, and dynamic ice shaping suggested that this cryopreservation protocol combined with the ACTIVE glycopeptide and trehalose could enhance the hydrogen bond network in nonfrozen solutions, resulting in inhibition of recrystallization and growth of ice. Therefore, the ACTIVE glycopeptide can be applied as a trehalose-associated "chaperone", providing a new way to serve as a candidate in glycerol-free human erythrocyte cryopreservation.

[Molecular analysis of 23 cases of B subgroup].

OBJECTIVE: To explore the molecular reasons of weak expression of B antigen on the red cell. METHODS: Serological test for blood group was carried out, including red cell and plasma grouping, and anti-A1 and anti-H testing, and confirming weak A or B antigens by adsorption and elution. Exons 1-7 were sequenced directly, and one of them was cloned and sequenced. RESULTS: All of the 23 samples showed the weak B antigen by serological method. The alleles of the subgroups were identified by DNA sequencing, including 2 Bel subgroup, 4 B3 subgroup, 14 Bw subgroup, 2 CisAB subgroup and a novel allele. The novel allele showed a nucleotide substitution 662G>A in the exon 7, and the sequence was submitted to Blood Group Antigen Gene Mutation Database, and the novel allele was named Bel10. CONCLUSION: Nucleotide substitution in exon results in blood subgroup, which showed that the antigens were weakened, and Bw phenotype was the most frequently subgroup.

Identification and Blood Transfusion of Rare B(A) Blood Group.

BACKGROUND: To study serologic and gene characteristics of the B(A) blood group of one patient in Tianjin, China. To investigate the blood transfusion for patients with B(A) blood group. METHODS: ABO subgroups were identified by standard serologic techniques in ABO typing discrepancy sample from one patient at the Tianjin Medical University General Hospital. DNA (deoxyribonucleic acid) was collected from his sample and PCR (polymerase chain reaction) was used to sequence exons 6 and 7. PCR products were sequenced to identify ABO subgroups and the B(A) allele. Molecular genotyping of the ABO gene was performed by DNA sequencing of exons 6 and 7 of the ABO gene. RESULTS: The patient's red cells showed mixed field agglutination reaction (MF) with anti-A and weak reaction (W+) with anti-H. However, it has strong agglutination reaction with anti-B. The patient's serum showed the presence of anti-A antibody, while it can't react with B cell. The serological characteristics of the patient's red cells were similar to AxB subtype. Variation sites were confirmed at 261delG, 297 A>G, 526 C>G, 640 A>G, 657 C>T, 703 G>A, 796 C>A, 803 G>C, 930 G>A in exon 6 and 7 of the ABO gene. The sequence was similar to B101 except for nt640 (A>G). Genotyping indicated that the specimen was B(A)04. CONCLUSIONS: Molecular genotyping confirmed the ABO status as B(A)04. The B(A) blood group is associated with a complicated serologic phenotype and DNA detection is necessary for this atypical phenotype sample. To ensure the safety of transfusion, this study developed an emergency transfusion procedure for patients with B(A) type.

A Dynamic Membrane-Active Glycopeptide for Enhanced Protection of Human Red Blood Cells against Freeze-Stress.

Intracellular delivery of freezing-tolerant trehalose is crucial for cryopreservation of red blood cells (RBCs) and previous strategies based on membrane-disruptive activity usually generate severe hemolysis. Herein, a dynamic membrane-active glycopeptide is developed by grafting with 25% maltotriose and 50% p-benzyl alcohol for the first time to effectively facilitate entry of membrane-impermeable trehalose in human RBCs with low hemolysis. Results of the mechanism acting on cell membranes suggest that reversible adsorption of such benzyl alcohol-grafted glycopeptide on cell surfaces upon weak perturbation with phospholipids and dynamic transition toward membrane stabilization are essential for keeping cellular biofunctions. Furthermore, the functionalized glycopeptide is indicative of typical α-helical/ß-sheet structure-driven regulations of ice crystals during freeze-thaw, thereby strongly promoting efficient cryopreservation. Such all-in-one glycopeptide enables achieving both high cell recovery post-thaw >85% and exceptional cryosurvival >95% in direct freezing protocols. The rationally designed benzyl alcohol-modified glycopeptide permits the development of a competent platform with high generality for protection of blood cells against freeze-stress.

NonFreezable Preservation of Human Red Blood Cells at -8 °C.

Red blood cell (RBC) preservation is very important in human health. The RBCs are usually preserved at 4 ± 2 °C without freezing or at a very low temperature (-80 °C or liquid nitrogen) with deep freezing. Herein, non freezable preservation of RBCs at a subzero temperature is reported to prolong the preservation time compared with that at 4 ± 2 °C. By adding glycerol and poly(ethylene glycol) (PEG) (average number molecular weight 400, PEG-400) into the preservation solution, the freezing point is decreased and the hemolysis is kept low. The cell metabolism of stored RBCs at -8 °C is reduced, and the shelf life of RBCs extends up to at least 70 days. At the end of preservation, the pH decreases a little bit to demonstrate the low metabolic rate of RBCs stored at subzero temperatures. After quick washing, the RBC survival rate is ca. 95%. The adenosine triphosphate, 2,3-diphosphoglycerate, and cell deformation ability of the washed RBCs are maintained at a high level, while the malondialdehyde is relatively low, which verifies the high quality of RBCs stored at this condition.

Cryopreservation of human erythrocytes through high intracellular trehalose with membrane stabilization of maltotriose-grafted ε-poly(L-lysine).

Cryopreservation of human erythrocytes via suitable cryoprotectants is essential for transfusion during emergencies, but the conventional glycerolization method requires a tedious thawing-deglycerolization process. Alternatively, trehalose, a nonreducing disaccharide, has gained much attention as a biocompatible cryoprotectant due to its nature in living organisms capable of surviving extreme cold and desiccation. In this work, cryopreservation of human erythrocytes was realized through high intracellular trehalose enhanced by benzyl alcohol at 4 °C with membrane stabilization of maltotriose-grafted ε-poly(L-lysine). Intracellular trehalose could reach 94.2 ± 12.1 mM with slight impacts on morphology and cell functions, and the post-storage cryosurvival of human erythrocytes could achieve 96.2 ± 3.4% via membrane protection by the glycopeptide. It has been demonstrated that the functional glycopeptide performed as an extracellular cryoprotectant accompanied by high intracellular trehalose for synergistic cryopreservation of human erythrocytes in the biocompatible glycerol-free conditions. This two-step approach involving augmentation of intracellular trehalose at a hypothermic temperature and membrane stabilization of the functional glycopeptide could be an alternative way for human cell cryopreservation.

Membrane stabilization versus perturbation by aromatic monoamine-modified γ-PGA for cryopreservation of human RBCs with high intracellular trehalose.

As a nonreducing disaccharide, trehalose can be used as a biocompatible cryoprotectant for solvent-free cell cryopreservation, but the membrane-impermeability limits its cryoprotective efficiency. Herein, a series of aromatic monoamines with a 1-4 methylene spacer were grafted onto γ-poly(glutamic acid) (γ-PGA) for promoting intracellular trehalose uptake in human red blood cells (hRBCs) via membrane perturbation. The self-assembled nanoparticles of the obtained amphiphilic γ-PGA could be adsorbed on the cell membrane by the hydrophobic interaction to disturb the lipid arrangement and increase the membrane permeability of trehalose under hypertonic conditions. Results suggested that the intracellular trehalose could be enhanced progressively with the methylene spacer length, significantly increasing to 75.1 ± 0.7 mM by incubating hRBCs in 0.8 M trehalose containing phenylbutylamine-grafted γ-PGA at 4 °C for 24 h. Meanwhile, the other three polymers exhibited membrane stabilization in addition to improved intracellular trehalose, maintaining the membrane integrity during cryopreservation to achieve high cryosurvival. Molecular dynamics simulation further confirmed that defects could be formed by interaction of the above four amphiphilic polymers on the modeled phospholipid bilayer. It was believed that glycerol-free cryopreservation of human cells could be realized by using trehalose as the biocompatible cryoprotectant, and membrane stabilization can be a compensatory approach to membrane perturbation during impermeable biomolecule delivery.

The hyposensitive N187D P2X7 mutant promotes malignant progression in nude mice.

Nucleotides are new players in the intercellular communication network. P2X7 is a member of the P2X family of receptors, which are ATP-gated plasma membrane ion channels with diverse biological functions. Abnormal expression and dysfunction of P2X7 have been reported in leukemias. Here, we report a new P2X7 mutant (an A(559)-to-G substitution causing N187D P2X7) cloned from J6-1 leukemia cells. The characteristics of N187D P2X7 were studied by establishing stably transfected K562 cell lines. Our results show that N187D P2X7 required a higher concentration of agonist for its activation, leading to Ca(2+) influx (EC(50) = 293.3 ± 6.6 µm for the mutant and 93.6 ± 2.2 µm for wild-type P2X7) and ERK phosphorylation, which were not caused by differential cell-surface expression or related to high ATPase activity on the cell surface and in the extracellular space. K562 cells expressing this N187D mutant showed a proliferative advantage and reduced pro-apoptosis effects in vitro and in vivo. Furthermore, elevated angiogenesis and CD206-positive macrophage infiltration were found in tumor tissues formed by K562-M cells. In addition, higher expression of VEGF and MCP1 could be detected in tumor tissues formed by K562-M cells. Our results suggest that N187D P2X7, representing mutants hyposensitive to agonist, might be a positive regulator in the progression of hematopoietic malignancies.

Abnormal expression of ADAR1 isoforms in Chinese pediatric acute leukemias.

The posttranscriptional RNA editing by the type 1 adenosine deaminase acting on RNAs (ADAR1), expressed as p110 and p150 isoforms, is important for both physiological and pathological processes. Their expression and significance in leukemias remain unknown. Here, we investigated the expression of ADAR1 in Chinese pediatric acute leukemias by real-time PCR and Western blot. The results showed that significant high expression of p110 was detected in leukemias, especially in B-ALL, whereas a slight increase of p150 could be observed. Furthermore, the decrease of p110 expression was observed in B-ALL patients achieving complete remission. Moreover, among prognostic risk groups in ALL, the highest expressions of p110 and p150 were detected in standard-risk group, whereas their lowest expressions were in high-risk group. This observation was further confirmed in comparisons between good and poor prognostic groups based on prognostic related clinical features. These results demonstrated that ADAR1 isoforms showed different expression patterns, suggesting that they might play different roles in pediatric leukemias. Our results will help us for the better understanding of RNA editing, exploring the potential target for the treatment, and making prognostic evaluation in childhood leukemias.

Abnormal expression of P2X family receptors in Chinese pediatric acute leukemias.

Nucleotides are new players in intercellular communication network. P2X family receptors are ATP-gated plasma membrane ion channels with diverse biological functions. Their distribution patterns and significance in pediatric leukemias have not been established. Here we investigated the expression of P2X receptors in BMMC samples from Chinese pediatric acute leukemias. Real-time PCR and Western blot results showed that P2X1, P2X4, P2X5 and P2X7 receptors were simultaneously over expressed in leukemias compared with controls, whereas P2X2, P2X3 and P2X6 were absent or marginally expressed in both groups. It was worth noting that the co-expression feature of them, especially between P2X4 and P2X7, could be observed and the highest expression of P2X7 was detected in relapsed patients. Moreover, concomitant decrease of P2X4, P2X5 and P2X7 expressions was observed at CR stage in a follow-up study. Functional P2X7 was also verified. These results suggested that P2X1, P2X4, P2X5 and P2X7 were hematopoiesis-related P2X receptors, and their signaling, especially for P2X7, might play important roles in pediatric leukemias. P2X receptors might co-operatively contribute to the malignant phenotype in human pediatric leukemias.

[Construction and expression of the recombinant plasmid containing BddhFVIII in HepG2 cells].

OBJECTIVE: To get stable cell line expressing B domain-deleted human FVIII (BDDhFVIII) by constructing the eukaryotic expression plasmid. METHODS: Eukaryotic expression plasmid containing BDDhFVIII was constructed and transfected into HepG2 cells via electroporation. The expression and purification of the target protein was detected by Western blot. RESULTS: Results of enzyme digestion and sequence analysis demonstrated that the gene of BDDhFVIII was correctly inserted into the eukaryotic expression vector pcDNA4/v5-his. Western blot confirmed the successful expression of BDDhFVIII at the protein levels in HepG2 cells. CONCLUSION: The constructed eukaryotic expression vector was able to generate high level expression of human FVIII in HepG2 cells, thus could construct human blood coagulation FVIII stable cell line successfully.

[Expression of ADAR1 isoforms in murine acute T-ALL leukemia model].

This study was purposed to investigate the expression of ADAR1 isoforms of P110 and P150 during the development of murine leukemia. A Notch1 over-expressing murine T cell acute lymphoblastic leukemia model was used to study the expression of ADAR1. BMMNC were isolated at different stages of disease and CD45.2(+)GFP(+) leukemia cells were sorted by flow cytometry at late stage. The expression of ADAR1 was detected by real time quantitative PCR. The results showed that mouse bone marrow cells from both leukemia and control groups expressed P110 and P150. Difference of P110 and P150 mRNA expression were observed during the development of leukemia. The expression of P110 dramatically increased and was significantly higher than that in control group. However, the expression level of P150 in leukemia group decreased stably and reached one-fourth of that in control group at 14 day. Furthermore, similar expression patterns could be detected in sorted CD45.2(+)GFP(+) leukemia cells. It is concluded that the mRNA expressions of P110 and P150 show diverse patterns in the development of leukemia, suggesting that RNA editing mediated by ADAR1 isoforms may play different roles in leukemia.

A special linker between macrophage and hematopoietic malignant cells: membrane form of macrophage colony-stimulating factor.

The membrane form of macrophage colony-stimulating factor (mM-CSF) is an alternative splicing variant of this cytokine. Although its high expression was detected in hematopoietic malignancies, its physiologic and pathologic roles in hematopoietic system have not been established. In this report, stable transfectant clones expressing mM-CSF (Namalwa-M and Ramos-M) were obtained, which showed reduced proliferation potential in vitro. Moreover, the in vivo study showed that Namalwa-M and Ramos-M exhibited enhanced oncogenicity in tumor size in nude mice model, which could be inhibited by M-CSF monoclonal antibody. A remarkable increase in infiltrating macrophage and the vessel densities was found in tumor tissues formed by lymphoma cell lines that stably expressed mM-CSF, which suggested the involvement of macrophages in this process. The in vitro results using coculture system showed that macrophages could promote Namalwa-M and Ramos-M proliferation and activate extracellular signal-regulated kinase/mitogen-activated protein kinase signal pathway. In addition, the expression of murine origin vascular endothelial growth factor, basic fibroblast growth factor, and hepatocyte growth factor was elevated in Namalwa-M formed tumor tissues. These results suggested that mM-CSF should be a positive regulator in the development of hematopoietic malignancies by abnormally activating infiltrating macrophages, which in turn promote the malignant development. Thus, mM-CSF may be a critical linker between macrophages and malignant cells in the development of hematopoietic malignancies.