Triterpenoids from the Leaves of Diospyros digyna and Their PTP1B Inhibitory Activity.

Six new 2α-hydroxy ursane triterpenoids, 3α-cis-p-coumaroyloxy-2α,19α-dihydroxy-12-ursen-28-oic acid (1), 3α-trans-p-coumaroyloxy-2α,19α-dihydroxy-12-ursen-28-oic acid (2), 3α-trans-p-coumaroyloxy-2α-hydroxy-12-ursen-28-oic acid (3), 3ß-trans-p-coumaroyloxy-2α-hydroxy-12,20(30)-ursadien-28-oic acid (4), 3ß-trans-feruloyloxy-2α-hydroxy-12,20(30)-ursadien-28-oic acid (5), and 3α-trans-feruloyloxy-2α-hydroxy-12,20(30)-ursadien-28-oic acid (6), along with eleven known triterpenoids (7-17), were isolated from the leaves of Diospyros digyna. Their chemical structures were elucidated by comprehensive analysis of UV, IR, HRESIMS, and NMR spectra. All the isolated compounds were evaluated for their PTP1B inhibitory activity. 3ß-O-trans-feruloyl-2α-hydroxy-urs-12-en-28-oic acid (13) showed the best inhibition activity with an IC50 value of 10.32 ± 1.21 µM. The molecular docking study found that the binding affinity of compound 13 for PTP1B was comparable to that of oleanolic acid (positive control).

Circ_0004872 deficiency attenuates ox-LDL-induced vascular smooth muscle cell dysfunction by miR-424-5p-dependent regulation of FRS2.

Atherosclerosis (AS) is a pivotal pathological basis of cardiovascular and cerebrovascular diseases, and circular RNAs (circRNAs) has been disclosed to exert a vital part in the progression of AS. However, the functions of circ_0004872 in the progression of AS is indistinct. In this context, we aimed to elucidate the role of circ_0004872 and the potential mechanism in AS. The level of circ_0004872, miR-424-5p and fibroblast growth factor receptor substrate 2 (FRS2) was detected using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was monitored by Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine (EDU) assays. The invasion and migration capabilities of VSMCs were tested by transwell assays and wound-healing assay, respectively. Western blot was adopted to check the protein levels of CyclinD1, Vimentin and FRS2. Dual-luciferase reporter and RNA immunoprecipitation assay were executed to manifest the interaction between miR-424-5p and circ_0004872 or FRS2. The level of circ_0004872 was increased in the serum samples of AS patients and ox-LDL-exposed VSMCs. Ox-LDL exposure triggered cell proliferation, invasion and migration ability of VSMCs. depletion of circ_0004872 partly weakened ox-LDL-mediated effects in VSMCs. Mechanistically, circ_0004872 functioned as a sponge of miR-424-5p, and miR-424-5p inhibition partly alleviated circ_0004872 deficiency-mediated influences in VSMCs. Additionally, miR-424-5p interacted with FRS2, and miR-424-5p constrained dysfunction in ox-LDL-stimulated VSMCs via reducing FRS2 level. Notably, circ_0004872 functioned as a sponge of miR-424-5p to elevate FRS2 expression. Circ_0004872 accelerated ox-LDL-induced damage via mediating miR-424-5p/FRS2 axis.

Self-Assembly of Palmitic Acid in the Presence of Choline Hydroxide.

To disperse fatty acids in aqueous solution, choline, a quaternary ammonium ion, has been used recently. So far, only the self-assembly of myristic acid (MA) in the presence of choline hydroxide as a function of the molar ratio has been investigated, and, thus, the current understanding of these fatty acid systems is still limited. We investigated the self-assembly of palmitic acid (PA) in the presence of choline hydroxide (ChOH) as a function of the molar ratio (R) between ChOH and PA. The self-assemblies were characterized by phase contrast microscopy, cryo-TEM, small-angle X-ray scattering, and 2H NMR. The ionization state of PA was determined by pH, conductivity, and FT-IR measurements. With increase in R, various self-assembled structures, including vesicles, lamellar phase, rigid membranes (large sheets, tubules, cones, and polyhedrals), and micelles, form in the PA/ChOH system, different from those of the MA/ChOH system. The change in R induces pH variation and, consequently, a change in the PA ionization state, which, in turn, regulates the molecular interactions, including hydrogen bonding and electrostatic interaction, leading to various self-assemblies. Temperature is an important factor used to tune the self-assembly transitions. The fatty acid choline systems studied here potentially may be applicable in medicine, chemical engineering, and biotechnology.

The spatial pattern of Scirpus mariqueter expansion and the associated mechanism of self-organization using unmanned aerial vehicles and its significance for coastal wetland restoration.

Understanding the spatial expansion process of salt marshes and quantifying the factors driving this expansion are crucial for the management and restoration of coastal wetlands. In this study, we aimed to illustrate the expansion process of Scirpus mariqueter using drone remote sensing and quantify its relationship with habitat quality. Our hypothesis was that landscape metrics could serve as valuable indicators for prioritizing habitat restoration efforts along the coast. We utilized drone remote sensing and adopted the simple Greenness Index to reflect the growth status of S. mariqueter. Using this index, we computed the standard deviation ellipse and growth center. To evaluate habitat quality, we developed a method based on our previous research and other relevant reports. We then conducted a quantitative analysis of the expansion process of S. mariqueter in areas with varying habitat quality. We found that S. mariqueter's optimal elevation was 3.7 m, with a range of 2.5 to 4.3 m. The threshold value for soil total nitrogen was 0.3 g/kg, and the tolerance threshold for soil salinity was 2500 ppm. These three factors, elevation, soil total nitrogen, and soil salinity, collectively influenced habitat quality, with weights of 0.68, 0.23, and 0.09, respectively, as determined through geodetector analysis. During the summer, we observed a dominance of dispersal in S. mariqueter, with the species primarily spreading to areas with increased habitat quality. Patch shapes tended to be compact and regular in this season. In contrast, during the autumn, a dominance of decline was observed, with S. mariqueter mainly distributing to areas exhibiting decreased habitat quality. Patch shapes tended to be complex and irregular in the autumn season. Eventually micro-geomorphic modification and patch shape filling methods based on UAV observations are proposed to aid wetland restoration. These findings are of utmost importance for the restoration of coastal wetlands and the enhancement of ecosystem resilience.

The role of phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG1) in regulating the progression of oral squamous cell carcinoma.

OBJECTIVE: The aim of this study was to explore the role of the tumor suppressor phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG1) on oral squamous cell carcinoma (OSCC) and its molecular mechanism. DESIGN: Immunohistochemistry detected the expression of PAG1 in normal and tumor tissues. The PAG1 overexpressed OSCC cell lines were constructed by lentivirus transfection. Cell Counting Kit-8 assay (CCK-8), clone formation and flow cytometry evaluated the impact of PAG1 on the proliferation and apoptosis of OSCC cells. RNA sequencing (RNA-seq) detected the changes in intracellular genes, and transmission electron microscope (TEM) was used to compare the number of autophagosomes in OSCC cells between Negative and PAG1 group. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and Western blot were used to determine the expression of signaling pathway-related mRNA and proteins respectively. RESULTS: In contrast to the normal tissues, PAG1 expression was significantly downregulated in tumor tissues. Treatment with lentivirus transfection, the expression of PAG1 in the OSCC cell lines was increase. Notably, transfected with PAG1-overexpressing lentivirus cells inhibited the proliferation of OSCC cells and promoted OSCC cells apoptosis. RNA-seq revealed that PAG1 mainly modulated the mitophagy and autophagy pathway, and many autophagosomes were observed in the PAG1 group using TEM. Mechanistically, we found that PAG1 upregulated the expression of autophagy related factors through inhibiting PI3K/Akt/mTOR signal pathway activation. CONCLUSION: Overexpression of PAG1 inhibited OSCC progression by activating autophagy, its mechanism might be related to inhibition of PI3K/Akt/mTOR signal pathway phosphorylation.

Effect of psoralen on the regulation of osteogenic differentiation induced by periodontal stem cell-derived exosomes.

Periodontitis is a chronic inflammatory disease that is the main cause of tooth loss in adults, and the key to periodontitis treatment is the repair and regenerate of periodontal bone tissue. Psoralen is the main component of the Psoralea corylifolia Linn, which shows antibacterial, anti-inflammatoryand osteogenic activities. It promotes the differentiation of periodontal ligament stem cells toward osteogenesis. Exosomes secreted by stem cells play important roles in information transmission during the osteogenic differentiation process. The aim of this paper was to investigate the role of psoralen in regulating osteogenic miRNA information in periodontal stem cells and in periodontal stem cells exosomes and the specific mechanism of its action. Experimental results show that exosomes of human periodontal ligament stem cell origin treated with psoralen (hPDLSCs + Pso-Exos) were not significantly different from untreated exosomes (hPDLSC-Exos) in terms of size and morphology. Thirty-five differentially expressed miRNAs were found to be upregulated and 58 differentially expressed miRNAs were found to be downregulated in the hPDLSCs + Pso-Exos compared to the hPDLSC-Exos (P < 0.05). hsa-miR-125b-5p was associated with osteogenic differentiation. Among them, hsa-miR-125b-5p was associated with osteogenic differentiation. After hsa-miR-125b-5p was inhibited, the osteogenesis level of hPDLSCs was enhanced. In summary, the osteogenic differentiation of hPDLSCs was promoted by psoralen through the downregulation of hsa-miR-125b-5p gene expression in hPDLSCs, and the expression of the hsa-miR-125b-5p gene was also downregulated in exosomes. This finding provides a new therapeutic idea for using psoralen to promote periodontal tissue regeneration.

Exploring the Influence of Hepatitis B Immunoglobulin on the Immune Response to the Hepatitis B Vaccine in a Mouse Model.

Background: The extent to which maternal antibodies against the hepatitis B surface antigen (HBsAb) acquired transplacentally affect the immune responses to the hepatitis B vaccine (HBVac) in infants is still uncertain. Objective: To explore the impact of the HBsAb on the immune response to the HBVac in a mouse model. Methods: According to the doses of the HBVac (2, 5 µg) injected, 267 BALB/c mice were divided into two groups. Each group was subdivided into 3 subgroups based on the doses of the hepatitis B immunoglobulin (HBIG) (0, 25, 50 IU) administered. The HBsAb titers were detected 4 weeks after completing the HepB vaccination. Results: Among all the mice, 40 had an HBsAb titer <100 mIU/mL (non- or low-response to the HBVac). The rates of the HBsAb titer <100 mIU/mL in 0, 25 and 50 IU HBIG groups were 1.1%, 23.1%, and 20.7%, respectively. Multivariate logistic regression analysis showed that the risk factors for low- or non-response to the HBVac were injection with the HBIG, low HBVac dose, and hypodermic injection. The mean HBsAb titers (log10) reduced gradually in the 0, 25 and 50 IU HBIG groups (P<0.001). Conclusion: The HBIG administration has negative impacts on the peak level of the HBsAb and the rate of an effective immune response. This implies that the maternal HBsAb acquired transplacentally might inhibit the immune responses to the HBVac in infants.

Preparation of Novel ICT-CMC-CD59sp Drug-Loaded Microspheres and Targeting Anti-Tumor Effect on Oral Squamous Cell Carcinoma.

The treatment of oral squamous cell carcinoma (OSCC) remains a great clinical challenge, and the malignant proliferation of OSCC cells can lead to the overexpression of CD59. In this study, a novel microsphere (ICT-CMC-CD59sp) composed of icariin (ICT), carboxymethyl chitosan (CMC), and cell differentiation antigen 59-specific ligand peptide (CD59sp) was successfully prepared by using the emulsion cross-linking method. Through the guidance of CD59sp, the microspheres can target OSCC cells and play a therapeutic role (p < 0.01). The MTT test and trypan blue staining showed that the microspheres could promote the apoptosis of oral squamous cell carcinoma and had a significant difference (p < 0.01). In this study, the regulatory effect of the microspheres on OSCC cells was investigated at the cellular level, and its therapeutic effect on OSCC was discussed, which provided a new perspective for the targeted therapy of OSCC.

Spontaneous vesicle formation and vesicle-to-α-gel transition in aqueous mixtures of sodium monododecylphosphate and guanidinium salts.

Monoalkyl phosphates (MAPs) are one kind of important single-chain weak acid/salt type surfactants, but the understanding of their aggregation behavior in water is very limited due to their insolubility at room temperature. In the current work, the effect of guanidinium salts (GuSalts) on the solubility of sodium monododecylphosphate (SDP), a typical MAP, in water was determined at 25.0 °C, and the aggregation behavior of SDP in the GuSalt/water mixtures was investigated. The solubility of SDP is significantly improved by GuSalts including GuCl, GuSO4, GuSO3, GuPO4, and GuCO3 at 25.0 °C, resulting in an isotropic phase. SDP vesicles are spontaneously formed in the isotropic phase, with a critical vesicle concentration of ∼1.0 mM independent of the type of GuSalts. A "bridging dimer" mechanism is proposed to explain the formation of SDP vesicles. The SDP vesicles have a unilamellar structure with a size of ∼80 nm and an alkyl interdigitated degree of ∼25%, and exhibit size-selective permeability. Interestingly, a temperature-induced reversible transition between vesicles and α-gels was observed for the SDP/GuSalt/H2O systems when the SDP content is higher than 20 mM. The α-gels obtained are composed of vesicles and bilayer sheets, showing similar viscoelasticity to conventional gels, although their water content is as high as ∼98 wt%. The microviscosity of SDP vesicle membranes (ca. 35.79-49.34 mPa s at 25.0 °C) and the transition temperature between vesicles and α-gels (ca. 21.0-22.8 °C) are all dependent of the type of GuSalts. This work deepens the understanding of the aggregation behavior of MAPs and also provides valuable information for their practical applications.

The expression of membrane-bound complement regulatory proteins CD46, CD55 and CD59 in oral lichen planus.

OBJECTIVE: To investigate the expression levels of membrane-anchored complement regulatory proteins (mCRPs), CD46, CD55 and CD59 in oral lichen planus (OLP), and evaluate the activation status of complement. DESIGN: Thirty-seven cases of OLP patients (20 non-erosive OLP and 17 erosive OLP) and twenty healthy controls were recruited in this study. The proteins and mRNA expression levels of CD46, CD55 and CD59 in OLP tissues were detected by western blotting and RT-qPCR respectively, and the expression levels of complement C3 and sC5b-9 in OLP patients' saliva were detected by ELISA to evaluate the activation status of complement. In addition, mucosa tissues of another 3 non-erosive OLP patients and another 3 healthy controls were collected, and the epithelial layer of two groups were separated to culture primary keratinocytes in vitro. Immunofluorescence was used to further detect the expression of mCRPs at the cellular level. RESULTS: The levels of CD46, CD55 and CD59 in OLP tissues and cells were significantly decreased compared with those of the healthy control group, and the level of complement C3 in the patients' saliva was significantly decreased, while the level of sC5b-9 was increased. CONCLUSIONS: These results suggest that the reduced expression of mCRPs keeps the complement system in a continuously active state, which may be the reason of the persistent local immune inflammatory state in OLP. This study aimed to provide new insights for the etiology and therapy of OLP.

Vesicle formation of single-chain amphiphilic 4-dodecylbenzene sulfonic acid in water and micelle-to-vesicle transition induced by wet-dry cycles.

Simple single-chain amphiphiles (SCAs) can form vesicular structures in their single-component aqueous solutions, which has attracted great attention, but the understanding of their aggregation behavior is still limited. In this work, the aggregation behavior of 4-dodecylbenzene sulfonic acid (DBSA), a typical simple SCA, in water was investigated. The structure and properties of the aggregates formed were determined. In particular, the effect of wet-dry cycles on the structures of aggregates was examined. The mechanisms of aggregate formation and structural transition were discussed. It was found that the increase of DBSA concentration can drive the occurrence of a micelle-to-vesicle transition, showing a critical micelle concentration and critical vesicle concentration of ∼0.53 and 2.14 mM, respectively. The vesicles formed coexist with micelles in solution, with a unilamellar structure and ∼80 nm size, and exhibit size-selective permeability. In addition, the vesicles show remarkable stability upon long-term storage, exposure to high temperature, and freeze-thaw cycles. The H-bonding interaction between DBSA species and the interdigitated structure of alkyl chains in bilayers play a key role in the formation and stability of DBSA vesicles. Interestingly, it was found that the wet-dry cycle can induce a micelle-to-vesicle transition and an obvious increase in the size of the original vesicles, accompanied by the formation of some multilamellar vesicles. This work provides a better understanding of the aggregation behavior of simple SCAs in their single-component aqueous solutions.

An aqueous two-phase system formed in single-component solution of α-ketooctanoic acid.

Aqueous two-phase systems (ATPSs), consisting of two immiscible water-rich phases, have received great attention. So far, all of ATPSs reported are formed by two water-soluble compounds in aqueous media. Herein, we report an ATPS formed in the single-component aqueous solution of α-ketooctanoic acid (KOCOOH), a weakly acidic surfactant, without any additives. Its formation originates from the coexistence of micelles and vesicles in the system, the former existing in the upper phase and the latter in the lower phase. The phase behavior and microstructures of KOCOOH in aqueous solution were determined. A concentration-driven stepwise aggregation was identified for the KOCOOH solution. With an increase in the KOCOOH concentration, vesicles, oil droplets, micelles, strip bilayers, and planar lamellar phase form successively; macroscopically, the system exhibits a homogeneous transparent single-phase, turbid dispersion, two phases, a bluish single-phase, and a colorless transparent single-phase in turn. The constantly changing ionization state of KOCOOH in aqueous solution plays an important role in the phase and aggregate structure transition. This work deepens the understanding of ATPSs, and the ATPS formed by KOCOOH may have potential applications such as in the separation and purification of biomolecules and the construction of hierarchical protocell models.

Engineering Electrospun Nanofibers for the Treatment of Oral Diseases.

With the increase of consumption of high-sugar foods, beverages, tobacco, and alcohol, the incidence rate of oral diseases has been increasing year by year. Statistics showed that the prevalence of oral diseases such as dental caries, dental pulpal disease, and periodontal disease has reached as high as 97% in 2015 in China. It is thus urgent to develop functional materials or products for the treatment of oral diseases. Electrospinning has been a widely used technology that is capable of utilizing polymer solution to generate micro/nano fibers under an appropriate high voltage condition. Owing to their excellent structures and biological performances, materials prepared by electrospinning technology have been used for a wide range of oral-related applications, such as tissue restoration, controlled drug release, anti-cancer, etc. In this regard, this article reviews the application and progress of electrospun nanofibers to various oral diseases in recent years. Firstly, engineering strategies of a variety of nanofiber structures together with their resultant functions will be introduced. Then, biological functions of electrospun nanofibers as well as their applications in the treatment of oral diseases are summarized and demonstrated. Finally, the development viewpoint of functional nanofibers is prospected, which is expected to lay the foundation and propose the direction for further clinical application.

Three new bisflavonols from the seeds of Hovenia dulcis Thunb. and their anti-RSV activities.

Three novel bisflavonol derivatives, Hovenianins A-C, along with 12 known flavonoids were isolated and identified from the seeds of Hovenia dulcis Thunb. Their structures were established on the basis of spectroscopic methods (MS, UV, IR, 1D and 2D NMR) and electronic circular dichroism experiments. Hovenianin A (1) was the first dimer of flavonol linked dihydroflavonol via the B rings at C-2' and C-2″'positions to be found in nature. While Hovenianins BC (2-3) were a pair of diastereoisomeric bis-dihydroflavonols firstly reported in the Hovenia genus. The in vitro antiviral activity against respiratory syncytium virus (RSV) were evaluated by cytopathic effect (CPE) reduction assay. As a result, compounds 4, 5, and 10 displayed better antiviral effect against RSV A2 strains.

Simultaneous Determination of α-Glucosidase Inhibitory Triterpenoids in Psidium guajava Using HPLC-DAD-ELSD and Pressurized Liquid Extraction.

Psidium guajava, a popular food and medicine dual purposes plant cultivated in tropical and subtropical regions, has been widely used as food crop and folk medicine, such as anti-diabetes agent, around the world. Triterpenoids have been considered as the major active ingredients of P. guajava. In the present study, a high-performance liquid chromatography coupled with diode array and evaporative light scattering detectors (HPLC-DAD-ELSD) method was developed for simultaneous determination of nine triterpenoids in P. guajava. Pressurized liquid extraction (PLE) was performed for sample preparation, and the analysis was achieved on a Cosmosil 5C18-MS-II (Nacalai Tesque, Kyoto, Japan) column eluted with gradient 0.1% aqueous formic acid-methanol system. The drift tube temperature of ELSD was set at 40 °C, and nitrogen flow-rate was at 1.6 L/min. All calibration curves for the analytes showed good linear regression (R2 > 0.9992) within test ranges. The established method was validated for intra-day and inter-day precisions (RSDs < 5%) and accuracy (recovery 94.23-106.87%). The validated method was successfully applied to determinate nine triterpenoids in 15 samples from the leave or fruit of P. guajava. In addition, the α-glucosidase inhibition assay showed good α-glucosidase inhibition activity in almost all the determined triterpenoids. The present study suggested that triterpenoids should be the quality control markers for P. guajava and HPLC-DAD-ELSD was an effective tool for the quality control of P. guajava.

Study on the Role of Salivary Flora and NF-κB Inflammatory Signal Pathway in Oral Lichen Planus.

Oral lichen planus (OLP) is an inflammatory disease. It is believed that infection and immune dysfunction play a key role in its pathogenesis, but the specific mechanism of action remains unclear. The 16s rRNA high-throughput sequencing technique was used to analyze the microbial flora structure in the saliva of OLP patients and healthy controls. The relative abundance of Derxia, Haemophilus, and Pseudomonas in the saliva of the OLP group was lower than that of the healthy control group, but there was no significant difference in the overall structure of the microbial population. In addition, we measured the protein expression levels of toll-like receptor 4 (TLR4) and nuclear factor-kappab p65 (NF-κB p65) in the tissues of OLP patients, and found that there was a significant increase and positive correlation between them (r = 0.907, P = 0.034). The expression levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in the OLP group were consistent with those of NF-κB p65. Therefore, we believe that changes in the composition ratio of microbialflora break the original balance state of flora, promote the occurrence of immune inflammatory reaction, and then lead to the generation or aggravation of OLP disease. This discovery provides new ideas for further research on OLP initiation and immune regulation mechanism.

Four new corynanthe-type alkaloids from the roots of Alstonia scholaris.

Four new corynanthe-type alkaloids, meloslines C-F (1-4), together with four known ones (5-8) were isolated from the roots of Alstonia scholaris. Their structures including absolute configurations were elucidated by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation. Compounds 1 and 2 exhibited potent vasorelaxant activity on endothelium-intact renal arteries precontracted with KCl.

Overexpression of CD59 inhibits apoptosis of T-acute lymphoblastic leukemia via AKT/Notch1 signaling pathway.

BACKGROUND: T-acute lymphoblastic leukemia (T-ALL) was a hematological malignancy characterized by the accumulation of immature T cells in bone marrow and peripheral blood. In this study, we tried to explore the physiological role of CD59 in T-ALL. METHODS: In this study, we collected the bone marrow samples from 17 T-ALL patients and 38 healthy participants to find differences in CD59 expression patterns. Then, CD59 was over-expressed in T-ALL cell line Jurkat, and its biological functions were detected. In addition, in order to understand the active site of CD59, the Trp40 was mutated. Further, we constructed a mouse model by transplanting Jurkat cells into the nude mice to verify the function of CD59 in vitro. At last, mechanism studies were performed by western blot. RESULTS: We found that the proportion of T lymphocytes expressing CD59 in bone marrow of T-ALL patients was significantly higher than that of healthy individuals. Then, we found that the overexpression of CD59 in Jurkat cells was beneficial to the cell survival by inhibiting apoptosis and promoting IL-2 secretion. In this process, Trp40 of CD59 was a key functional site. Further, the high expression of CD59 inhibited apoptosis of bone marrow and peripheral blood cells, and promoted IL-2 secretion in mouse model. At last, mechanism studies showed that the activation of AKT, STAT5 and Notch1 signaling pathways in Jurkat cells, may be involved in the regulation of apoptosis by CD59; and mutation in the Trp40 affect the interaction of CD59 with these signaling pathways. CONCLUSIONS: In conclusion, CD59 inhibited apoptosis of T-ALL by regulating AKT/Notch1 signaling pathway, providing a new perspective for the treatment of T-ALL.

Overexpression of Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomains induces cluster of differentiation 59-mediated apoptosis in Jurkat cells.

Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomains (CBP/PAG) is a membrane-bound adaptor protein that downregulates the activation of Src family kinases present in lipid rafts. To elucidate the role of CBP/PAG in human T cell activation, a cell line overexpressing CBP/PAG was constructed and the function of CBP/PAG in Jurkat cells was examined. The present study revealed that increased CBP/PAG expression in T cells significantly enhanced their apoptosis and reduced cellular activation and proliferation. Overexpression of CBP/PAG suppressed the growth of Jurkat cells by recruiting c-Src and its negative regulator, C-terminal Src kinase (CSK), to lipid rafts. The negative regulation of CBP/PAG was enhanced in the presence of anti-cluster of differentiation (CD)59 monoclonal antibodies. In addition, a significant association was revealed between the location of CBP/PAG and CD59, which were co-expressed in the same region of the cell membrane, implicating a potential overlap of the elicited signaling pathways. These results indicate that CBP/PAG functions as a negative regulator of cell signal transduction and suggest that CD59 may strengthen the role of negative feedback regulation.

A role for GPI-CD59 in promoting T-cell signal transduction via LAT.

Cluster of differentiation 59 (CD59) is a glycosylphosphatidylinositol-anchored protein. Cross-linking of CD59 with specific monoclonal antibodies can cause a series of intracellular signal transduction events. However, the underlying molecular mechanisms are poorly understood. Linker for activation of T-cells (LAT) is a crucial adaptor protein in T-cell signaling, and its phosphorylation and palmitoylation are essential for its localization and function. In a previous study by the present authors, it was demonstrated that CD59 may be responsible for LAT palmitoylation, thereby regulating T-cell signal transduction. The present study detected the co-localization of LAT and CD59 in lipid rafts by transfecting Jurkat cells with lentivirus vectors carrying the LAT-enhanced green fluorescent protein fusion protein. In addition, LAT and CD59 were shown to have a synergistic effect on the proliferation of Jurkat cells. The results also indicated that CD59 may transfer the palmitate group from phosphatidylinositol to LAT to form LAT palmitate, which then localizes to lipid rafts to regulate T-cell activation. The results of the present study provided novel insights into the role of CD59 in T-cell signal transduction.