Efficient generation of induced pluripotent stem cell lines from healthy donors' peripheral blood mononuclear cells of different genders.

Peripheral blood mononuclear cell (PBMC) are recognized as a conveniently collected reprogramming resource. Several methods are available in academia to reprogram PBMC into induced pluripotent stem cells (iPSC). In this research, we reprogrammed PBMC of different genders by using non-integrative non-viral liposome electrotransfer containing the reprogramming factors OCT4, SOX2, KLF4, and c-MYC. The three obtained iPSC cell lines were karyotypically normal and showed significant tritiated differentiation potential in vitro and in vivo. Our study provided an efficient procedure for reprogramming PBMC into iPSC and obtained three well-functioning iPSC, that may contribute to advance personalized cell therapy in the future.

Deciphering the biotic and abiotic drivers of coalescence asymmetry between soil and manure microbiomes.

Manure application improves soil fertility, yet its implications on the success of invasion of manure-borne microorganisms in the soil are poorly understood. Here, we assessed the importance of abiotic and biotic factors in modulating the extent to which manure-borne fungal and bacterial communities can invade resident soil microbial communities. For this purpose, we applied varying frequencies of two different amounts of manure to nine soils differing in physico-chemical properties, as well as in land-use history, over 180 days and monitored changes in bacterial and fungal communities. Variance partitioning revealed differential contributions of abiotic and biotic factors to invasion success, which together accounted for up to 82 % of the variance explained. We showed that the effects of interactions between biotic and abiotic factors increased with coalescence frequency and manure amount for the bacterial and fungal communities, respectively. Both abiotic and biotic factors were important for modulating coalescence asymmetry for the bacterial community, whereas abiotic factors had a greater effect on the fungal community. These results provide new insights into the drivers of coalescence events between manure and resident soil microbial communities. Moreover, our findings highlight the roles of the mixing ratio and frequency of coalescence events in modulating the survival of manure-borne microorganisms.

Experimental Study on Thermal Conductivity of Water-Based Magnetic Fluid Loaded with Different Nanoparticles.

Magnetic fluids, a new type of energy transfer fluid with tunable properties, have garnered significant interest from researchers worldwide. Hybrid magnetic fluids prepared by adding different types of nanoparticles exhibit superior thermophysical properties and functional characteristics. In this paper, we prepared a water-based magnetic fluid loaded with multi-walled carbon nanotubes (MCNTs), silver (Ag), and copper (Cu) to enhance thermal conductivity. Using a transient double hot-wire method, we designed and built an experimental measurement system for the thermal conductivity of magnetic fluids with an average measurement error of less than 5%. We studied the thermal conductivity of hybrid magnetic fluids under different conditions and evaluated the advantages and disadvantages of various models, including the Maxwell model, H&C model, Tim model, Y&C model, and Evans model. Our results show that MF+MCNTs, MF+Ag, and MF+Cu nanofluids can all improve the thermal conductivity of the carrier fluid, with MF+MCNTs exhibiting the best improvement effect of 10.93%. Among the five models evaluated, the Evans model had the best predictive effect with a deviation range within 5%. This work provides theoretical and practical reference for enhancing the thermal conductivity of magnetic fluids and provides a more accurate theoretical model for calculating the thermal conductivity of hybrid magnetic fluids.

Tenofovir disoproxil fumarate mediates neuronal injury by inducing neurotoxicity.

PURPOSE: Highly active antiretroviral therapy (HAART) is an accepted treatment option for patients with virus infection. Mounting evidence indicated that persistent HAART treatment is implicated with increased morbidity of HIV-associated neurocognitive disorders (HAND) in patients. Tenofovir disoproxil fumarate (TDF), a novel nucleotide reverse transcriptase inhibitor (NRTI), was used in patients with HIV co-infected with HBV. And it is still a vital first-line antiretroviral compounds in HAART. However, whether persistent treatment with TDF is involved in HAND development remains to be further elucidated. In this study, we aimed to discuss the neurotoxicity of TDF. METHODS: We used SH-SY5Y cells and primary neuronal cells to evaluate the neurotoxicity of TDF in vitro. The cytotoxicity of TDF on SH-SY5Y cells and primary neuronal cells was evaluated by the cell viability and LDH levels by MTT assay and LDH kit, respectively. Hoechst 33342 staining, TUNEL assay and flow cytometry were performed to evaluate the cells apoptosis. The intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) production were measured by commercial kits. In addition, the activation level of caspase-3 was evaluated using spectrophotometry and western blotting. RESULTS: Our results showed that TDF treatment significantly induced cell viability and induced apoptosis of SH-SY5Y cells and primary neuronal cells. Furthermore, the ROS levels and MDA productions were significantly up-regulated in nerve cells treated with TDF.  CONCLUSION: Our findings indicated that TDF may induce neuronal cell apoptosis through increasing the intracellular ROS and the expression level of caspase-3, which may be related to the increasing prevalence of HAND.

Efficient generation of induced pluripotent stem cell lines from peripheral blood mononuclear cells.

Peripheral blood mononuclear cells (PBMCs) have been widely considered as a more convenient and almost unlimited reprogramming resource, while the reprogramming procedure and efficiency still need to be improved. We reprogrammed the PBMCs by using non-integrative non-viral vectors liposome electrotransfer containing the reprogramming factors OCT4, SOX2, KLF4, and c-MYC. The iPSC lines exhibited a normal karyotype with their corresponding PBMCs and exhibited significant cellular pluripotency. Teratoma formation assay revealed that the iPSCs we generated could differentiate into three embryonic germ layers. Our study provides a more effective procedure for peripheral blood monocyte reprogramming to iPSC, and promotes its future application.

Calculation of the Maximum Temperature of Diester-Based Magnetic Fluid Layers in High-Speed Seals.

Magnetic fluids, as smart nanomaterials, have been successfully used in sealing applications and other fields. However, the temperature of magnetic fluids in the sealing gap is a key factor affecting sealing performances, limiting their application in high-speed sealing fields. Since obtaining a direct measurement of the magnetic fluid's temperature is difficult, due to the small clearance, accurately calculating the maximum temperature of the magnetic fluid layer in high-speed seals is crucial. Herein, a mathematical model for calculating the maximum temperature of the magnetic fluid layer was established, by using a reasonable simplification of high-speed sealing conditions, and the calculation formula was modified by studying the rheological properties of the diester-based magnetic fluid. The results suggest that the calculation of the maximum temperature is influenced by viscous dissipation, and both are related to the rheological characteristics of magnetic fluids. When the influence of rheological properties is ignored, the calculation results are not accurate for higher-velocity seals, but the calculation model applies to lower-velocity seals. When the influence of rheological properties is considered, the calculation results obtained by the corrected formula are more accurate, and they are applicable to both lower- and higher-velocity seals. This work can help us more accurately and conveniently estimate the maximum temperature of magnetic fluids in high-speed seal applications, which is of theoretical and practical research significance for determining sealing performances and thermal designs.

Regulation Mechanism for Friction Coefficient of Poly(vinylphosphoric acid) (PVPA) Superlubricity System Based on Ionic Properties.

Adjustable lubrication aims to achieve active control of the relative motion of the friction interface, providing a new idea for intelligent operation. A new phenomenon of sudden changes of friction coefficient (COF) in the poly(vinylphosphoric acid) (PVPA) superlubricity system by mixing different lubricants, was found in this study. It was found that anions were the critical factor for the COF change. The change degrees of the COF were investigated by a universal micro tribometer (UMT). A quartz crystal microbalance (QCM)-D was used to analyze the adsorption quantity of anions on the PVPA surface. The hydratability of the PVPA interface was controlled by changing the anionic properties (the amount of charge and structure), thus regulating the COF. The adsorption difference of anions is an important reasoning of how anionic properties can regulate the hydratability. It was analyzed by molecular dynamics simulation. For anions carrying different numbers of charges or double bonds, the adsorption quantity of anions was mainly affected by the adsorption degree on the PVPA surface, while the adsorption quantity of anions with different molecular configuration was synergistically regulated by the adsorption degree and adsorption area of anions on the PVPA surface. This work can be used to develop smart surfaces for applications.

The epidemiology of atrial fibrillation in Chinese postmenopausal women and its association with age of menopause.

OBJECTIVES: To investigate the epidemiology of atrial fibrillation (AF) in postmenopausal women and to evaluate the association between age of menopause and AF. STUDY DESIGN: A total of 9117 postmenopausal women were selected from a cross-sectional study conducted among the general population of north-east China from September 2017 and March 2019. MAIN OUTCOME MEASURES: AF was diagnosed according to self-reported medical history of AF and/or current ECG findings. The epidemiology of AF including prevalence, awareness, use of anticoagulants and cardiovascular risk factors in postmenopausal women were carefully assessed. The association between age of menopause and AF was evaluated by stepwise logistic regression. RESULTS: The prevalence of AF was up to 1.1 % (95 % CI, 0.9 %-1.3 %) in postmenopausal women, but the awareness of it was 61.2 %. The proportion of AF patients requiring treatment with an oral anticoagulant (OAC) was as high as 87.8 % according to CHA2DS2-VASc score, while only 5.8 % of them received it. The prevalence of cardiovascular risks factors was high among postmenopausal women with AF, but awareness, treatment and control of these comorbidities were unacceptably low. Compared with the women with premature menopause (< 45 years), participants reporting onset of menopause at 50-54 years had a significantly lower risk of AF (OR 0.49, 95 % CI 0.27-0.91). CONCLUSIONS: The widespread use of OAC and the control of cardiovascular risk factors in postmenopausal women with AF was of great significance in preventing AF-related stroke. The history of premature menopause provided a reliable opportunity for primary prevention of AF.

MicroRNA-221 sensitizes chronic myeloid leukemia cells to imatinib by targeting STAT5.

MicroRNAs (miRNAs) are involved in various processes from the development to drug resistance of tumors, including chronic myeloid leukemia (CML). In this study, we examined the STAT5-related miRNA-expression profile in CML cell lines (K562 and imatinib-resistant K562/G) by quantitative real-time reverse-transcriptase polymerase chain reactions. MiR-221 expression was markedly decreased in K562/G cells and peripheral blood mononuclear cells from patients with treatment failure, when compared to imatinib-sensitive CML cells and patients with optimal responses respectively. We also observed the expression of STAT5 inversely correlated with miR-221 expression in K562 and KBM5 cells. Additionally, STAT5 was validated as a direct target of miR-221 in dual-luciferase reporter vector assays. MiR-221 restoration and STAT5 knockdown in K562/G cells increased the sensitivity of CML cells to imatinib by reducing the Bcl2: Bax ratio. Collectively, our data suggested that miR-221-STAT5 axis played crucial roles in controlling the sensitivity of CML cells to imatinib.

Combined usage of Wilms' tumor gene quantitative analysis and multiparameter flow cytometry for minimal residual disease monitoring of acute myeloid leukemia patients after allogeneic hematopoietic stem cells transplantation.

High expression of the Wilms' tumor gene (WT1) in acute myeloid leukemia (AML) has been considered as a sensitive marker of minimal residual disease (MRD). The present study investigated the significance of quantitative analysis of WT1 mRNA, combined with multiparameter flow cytometry (MFC) regarding its efficacy and prognostic as well as relapse prediction value for leukemia patients with hematopoietic stem cell transplantation. Reverse-transcription quantitative polymerase chain reaction analysis demonstrated that the expression of WT1 in the initial and relapse group was significant higher than that in the complete remission (CR) group (P<0.01). WT1 and the donor chimerism were negatively correlated (r=-0.73, P<0.05). In all AML patients, WT1 was the highest in the M3 subtype and the lowest in the M1 subtype. Follow-up of 12 AML patients demonstrated that WT1 gene expression levels markedly decreased after CR, but obviously increased after relapse, as did the rate of the leukemia cells detected by MFC. The combined usage of MFC and WT1 monitoring contributed to an improved detection rate of relapse (91.7%), and may be used to monitor MRD, assess the treatment efficacy and prognosis, and predict the risk of recurrence in leukemia patients without specific molecular markers after allogeneic hematopoietic stem cell transplantation.

Persistent STAT5-mediated ROS production and involvement of aberrant p53 apoptotic signaling in the resistance of chronic myeloid leukemia to imatinib.

The persistent activation of signal transducer and activator of transcription 5 (STAT5) may principally be attributed to breakpoint cluster region (BCR)-Abelson murine leukemia viral oncogene homolog 1 (ABL1), and have multi-faceted effects in the development of chronic myeloid leukemia (CML). The p53 protein network regulates important mechanisms in DNA damage repair, cell cycle regulation/checkpoints, and cell senescence and apoptosis, as demonstrated by its ability to positively regulate the expression of various pro-apoptotic genes, including B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax). In the present study, it was observed that the mRNA levels of STAT5A and STAT5B were upregulated in patients with imatinib-resistant CML and in the imatinib-resistant K562/G CML cell line. In addition, increased expression of STAT5 was observed in the BCR-ABL1 mutation group, compared with that in the non-BCR-ABL1 mutation group, regardless of patient imatinib resistance state. Elevated levels of reactive oxygen species (ROS) and DNA double-strand breaks were identified in K562/G cells using flow cytometric and phosphorylated H2AX (γ-H2AX) foci immunofluorescence assays, respectively, compared with the imatinib-sensitive K562 cells. The levels of intracellular ROS and γ-H2AX were decreased by the ROS scavenger (N-acetylcysteine), and ROS levels were also markedly reduced by STAT5 inhibitor (SH-4-54). In addition, imatinib significantly inhibited the proliferation of K562 and K562/G cells, with half maximal inhibitory concentration values of 0.17±0.07 and 14.78±0.43 µM, respectively, and the levels of apoptosis were significantly different between K562 and K562/G cells following treatment with imatinib. The mRNA and protein levels of STAT5 and mouse double minute 2 homolog (MDM2) were upregulated, whereas those of Bax were downregulated in K562/G cells, as determined using western blot analysis. Additionally, although the two cell lines exhibited relatively low protein expression levels of p53, lower levels of p53 and TPp53BP1 transcripts were detected in the K562/G cells. Taken together, these findings suggest that the resistance of CML to the tyrosine kinase inhibitor, imatinib, may be associated with persistent STAT5-mediated ROS production, and the abnormality of the p53 pathway.

Gaze Patterns in Auditory-Visual Perception of Emotion by Children with Hearing Aids and Hearing Children.

This study investigated eye-movement patterns during emotion perception for children with hearing aids and hearing children. Seventy-eight participants aged from 3 to 7 were asked to watch videos with a facial expression followed by an oral statement, and these two cues were either congruent or incongruent in emotional valence. Results showed that while hearing children paid more attention to the upper part of the face, children with hearing aids paid more attention to the lower part of the face after the oral statement was presented, especially for the neutral facial expression/neutral oral statement condition. These results suggest that children with hearing aids have an altered eye contact pattern with others and a difficulty in matching visual and voice cues in emotion perception. The negative cause and effect of these gaze patterns should be avoided in earlier rehabilitation for hearing-impaired children with assistive devices.

[Influences of biochar and nitrogen fertilizer on soil nematode assemblage of upland red soil].

The use of biochar as soil remediation amendment has received more and more concerns, but little attention has been paid to its effect on soil fauna. Based on the field experiment in an upland red soil, we studied the influences of different application rates of biochar (0, 10, 20, 30, 40 t · hm⁻²) and nitrogen fertilizer (60, 90, 120 kg N · hm⁻²) on soil basic properties and nematode assemblages during drought and wet periods. Our results showed that the biochar amendment significantly affect soil moisture and pH regardless of drought or wet period. With the increasing of biochar application, soil pH significantly increased, while soil moisture increased first and then decreased. Soil microbial properties (microbial biomass C, microbial biomass N, microbial biomass C/N, basal respiration) were also significantly affected by the application of biochar and N fertilizer. Low doses of biochar could stimulate the microbial activity, while high doses depressed microbial activity. For example, averaged across different N application rates, biochar amendment at less than 30 t · hm⁻² could increase microbial activity in the drought and wet periods. Besides, the effects of biochar also depended on wet or drought period. When the biochar application rate higher than 30 t · hm⁻², the microbial biomass C was significantly higher in the drought period than the control, but no differences were observed in the wet period. On the contrary, microbial biomass N showed a reverse pattern. Dissolved organic matter and mineral N were affected by biochar and N fertilizer significantly in the drought period, however, in the wet period they were only affected by N fertilizer rather than biochar. There was significant interaction between biochar and N fertilizer on soil nematode abundance and nematode trophic composition independent of sampling period. Combined high doses of both biochar and N fertilization promoted soil nematode abundance. Moreover, the biochar amendment increased the proportion of fungivores especially in the drought period, suggesting the biochar was the preferred fungal energy channel in comparison to soil without biochar addition. In summary, complex patterns occurred not only due to the application rate of biochar as well as their interactions with N fertilization but also due to the drought and wet periods. It is, therefore, necessary to consider different ecological factors when evaluating the effects of biochar in future.

Soil Nitrogen Status Modifies Rice Root Response to Nematode-Bacteria Interactions in the Rhizosphere.

It has been hypothesized that faunal activity in the rhizosphere influences root growth via an auxin-dependent pathway. In this study, two methods were used to adjust nematode and bacterial populations within experimental soils. One is "exclusion", where soil mixed with pig manure was placed in two bags with different mesh sizes (1mm and 5µm diameter), and then surrounded by an outer layer of unamended soil resulting in soil with a greater populations of bacterial-feeding nematodes (1mm) and a control treatment (5µm). The second method is "inoculation", whereby autoclaved soil was inoculated with bacteria (E. coli and Pseudomonas) and Nematodes (Cephalobus and C. elegans). In order to detect the changes in the rice's perception of auxin under different nutrient and auxin conditions in the presence of soil bacterial-feeding nematodes, responses of soil chemistry (NH4+, NO3- and indole acetic acid (IAA)), rice root growth and the expression of an auxin responsive gene GH3-2 were measured. Results showed that, under low soil nutrient conditions (exclusion), low NO3- correlated with increased root branching and IAA correlated with increased root elongation and GH3-2 expression. However, under high soil nutrient conditions (inoculation), a high NH4+ to NO3- ratio promoted an increase in root surface area and there was an additional influence of NH4+ and NO3- on GH3-2 expression. Thus it was concluded that soil bacterial-feeding nematodes influenced soil nutritional status and soil IAA content, promoting root growth via an auxin dependent pathway that was offset by soil nitrogen status.

The reduced bioavailability of copper by nano-TiO2 attenuates the toxicity to Microcystis aeruginosa.

Nano-TiO2 is a widely applied nanoparticle (NPs) and co-exists with other pollutants such as heavy metals in aquatic environments. However, minimal knowledge is available concerning the ecological risk of these mixtures. Our study reported that at no toxic effect concentrations of TiO2 nanoparticles (5 mg/L), the toxicity of Cu ions to the algae Microcystis aeruginosa was significantly attenuated by TiO2 nanoparticles. Specifically, the concentration of photosynthetic pigments (i.e., concentration of Chla) increased 37% when comparing only Cu ions treated and the nano-TiO2-Cu co-incubation. The levels of phycocyanin (PC), allophycocyanin (APC), phycoerythrin (PE), and phycobiliprotein (PBPs) were also recovered at levels ranging from 23 to 35% after 72 h. For oxidative indexes, the decreased activities of the superoxide dismutase (SOD), peroxidase (POD) content, and malondialdehyde (MDA) with the existence of nano-TiO2 displayed a lower level compared to Cu ions treatment only at 24 and 48 h. This toxicity attenuation can be confirmed by subcellular structures because the impairment to cellular membranes and organelles reduced with the presence of nano-TiO2. The potential mechanisms of the antagonism between the nano-TiO2 and Cu ions can be partially attributed to the sorption of copper onto TiO2 nanoparticles, which fitted the Freundlich isotherm (coefficient = 0.967). The decreased bioavailability of Cu ions protected algae cells from being attacked by free Cu ions. Given the abundance of released nanoparticles and unique physicochemical property of nanoparticles, our results elucidated the ecosafety of nanoparticles and co-substrates in aquatic systems.

[Observation on therapeutic effect of acupuncture combined with medicine on mild cognition disorders in patients with post-stroke].

OBJECTIVE: To explore the curative effect and safety of acupuncture for mild cognitive disorders after stroke. METHODS: Randomized controlled trial was adopted and one hundred cases conforming to criteria were divided into a combined acupuncture and medication group (group A) and a medication group (group B), 50 cases in each group. The basic treatment of cerebrovascular disease was applied in two groups. The group A treated was with acupuncture at Baihui (GV 20), Shenting (GV 24) and Qucha (BL 4) etc. and oral administration of Nimodipine. In group B, Nimodipine was taken orally. The treatment lasted for 3 months, the scores of Mini-Mental State Examination (MMSE), modified Hasegawa Dementia Scale (HDS-R) and Barthel Index (BI) were observed before and after treatment in two groups. RESULTS: The total effective rate in group A was 66.7% (32/48), which was superior to 30.4% (14/46) in group B (P < 0.05). The scores of MMSE, HDS-R and BI after treatment were apparently improved as compared with those before treatment in two groups (all P < 0.01). The improvements in group A were superior to those in group B (all P < 0.05). There was no adverse event reported during the treatment in two groups. CONCLUSION: Acupuncture can improve activity of daily living and has significant effect in treating mild cognition disorders after stroke without adverse reactions.

[Clinical observation on therapeutic effect of three-step acupuncture for the secondary prevention of ischemic cerebral apoplexy].

OBJECTIVE: To observe the therapeutic effect and safety of three-step acupuncture for the secondary prevention of ischemic cerebral apoplexy. METHODS: One hundred and twenty cases of first-episode ischemic cerebral apoplexy were randomly divided into an observation group and a control group according to the visiting sequence, 60 cases in each group. Both groups were treated on the basis of the routine treatment, the observation group was treated with three-step acupuncture combined with oral administration of Aspirin for six months. The threestep acupuncture includs scalp acupuncture, body point acupuncture and rehabilitation training. The control group was treated with oral administration of Aspirin alone. Six-month follow-up was done in two groups. Then the recurrence rate of ischemic cerebral apoplexy, the improvement of neurologic impairment, activity of daily living and TCM symptom scores and the safety of three-step acupuncture between two groups were compared. RESULTS: The recurrence rate was 10.2% (5/49) in observation group, and 16.7% (9/54) in control group. There was no significant difference between two groups (P > 0.05). The observation group was superior to the control group in improving the scores of the neurologic impairment, activity of daily living and TCM symptom (P < 0.01, P < 0.001). There was no severe adverse reaction in two groups except 2 cases of gastrointestinal reaction caused by oral administration of Aspirin in control group. CONCLUSION: Three-step acupuncture has a certain therapeutic effect for both treatment and the secondary prevention of ischemic cerebral apoplexy, and it is one of the safe and effective methods for treating and preventing ischemic cerebral apoplexy in clinic.

Determination of Prometryne in water and soil by HPLC-UV using cloud-point extraction.

A CPE-HPLC (UV) method has been developed for the determination of Prometryne. In this method, non-ionic surfactant Triton X-114 was first used to extract and pre-concentrate Prometryne from water and soil samples. The separation and determination of Prometryne were then carried out in an HPLC-UV system with isocratic elution using a detector set at 254 nm wavelength. The parameters and variables that affected the extraction were also investigated and the optimal conditions were found to be 0.5% of Triton X-114 (w/v), 3% of NaCl (w/v) and heat-assisted at 50 degrees C for 30 min. Using these conditions, the recovery rates of Prometryne ranged from 92.84% to 99.23% in water and 85.48% to 93.67% in soil, respectively, with all the relative standard deviations less than 3.05%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.5 microg L(-1) and 11.0 microg L(-1) in water and 4.0 microg kg(-1) and 13.0 microg kg(-1) in soil, respectively. Thus, we developed a method that has proven to be an efficient, green, rapid and inexpensive approach for extraction and determination of Prometryne from soil samples.

[Community structure of collembolan in degraded red soil under different restoration vegetation types].

With the degraded red soils of eroded bare land (I), xeric mesophilous herbosa (II), sparse coniferous woodland (III), coniferous woodland (IV), coniferous-broadleaf mixed woodland (V), and evergreen broadleaf forest (CK) as test objects, this paper studied the effects of vegetation restoration on the collembolan communities in degraded red soil. A total of 23 genera belonging to seven families and two suborders were observed, including dominant taxa such as Folsomia, Folsomina, and Sminthurinus. The characteristics of soil collembolan community were analyzed by using the indices such as individual density, taxa number, diversity, abundance, and evenness. The test indices were the lowest in I, and the highest in CK. The soil collembolan communities in II, III, IV and V were restored to some extent, but the restoration was still at early stage, with less difference observed. Bray-Curtis index had the largest difference (0.99) between eroded bare land and CK, larger differences between the four restored plantations and CK, and less difference between four restored plantations.

Overexpression of sorcin in multidrug resistant human leukemia cells and its role in regulating cell apoptosis.

In an attempt to identify novel proteins involved in the emergence of multidrug resistance (MDR) in leukemia cells, we adopted a proteomics approach to analyze protein expression patterns in leukemia cell lines, K562, and its MDR counterpart, K562/A02. Combining high-resolution two-dimensional gel electrophoresis and mass spectrometry, we compared the protein expression profiles between K562 and K562/A02. A total number of 22 protein spots with altered abundances of more than 2-fold were detected and 14 proteins were successfully identified. Consistent with our previous observations by cDNA microarray, sorcin, a 22-kDa calcium-binding protein, was also identified by this proteomic approach with a 10.4-fold up-regulation in K562/A02 cells. Overexpression of sorcin protein in K562 cells by gene transfection led to significantly reduced cytosolic calcium level and increased resistance to cell apoptosis. Further, leukemia cell lines over-expressing sorcin also showed up-regulation of Bcl-2, along with decreased level of Bax. Taken together, our results suggest that sorcin plays an important role in the emergence of MDR in leukemia cells via regulating cell apoptosis pathways, thus may represent both a new MDR marker for prognosis and a good target for anti-MDR drug development.