Oncogenic FLT3 internal tandem duplication activates E2F1 to regulate purine metabolism in acute myeloid leukaemia.

Oncogene FLT3 internal tandem duplication (FLT3-ITD) mutation accounts for 30 % of acute myeloid leukaemia (AML) cases and induces transformation. Previously, we found that E2F transcription factor 1 (E2F1) was involved in AML cell differentiation. Here, we reported that E2F1 expression was aberrantly upregulated in AML patients, especially in AML patients carrying FLT3-ITD. E2F1 knockdown inhibited cell proliferation and increased cell sensitivity to chemotherapy in cultured FLT3-ITD-positive AML cells. E2F1-depleted FLT3-ITD+ AML cells lost their malignancy as shown by the reduced leukaemia burden and prolonged survival in NOD-PrkdcscidIl2rgem1/Smoc mice receiving xenografts. Additionally, FLT3-ITD-driven transformation of human CD34+ hematopoietic stem and progenitor cells was counteracted by E2F1 knockdown. Mechanistically, FLT3-ITD enhanced the expression and nuclear accumulation of E2F1 in AML cells. Further study using chromatin immunoprecipitation-sequencing and metabolomics analyses revealed that ectopic FLT3-ITD promoted the recruitment of E2F1 on genes encoding key enzymatic regulators of purine metabolism and thus supported AML cell proliferation. Together, this study demonstrates that E2F1-activated purine metabolism is a critical downstream process of FLT3-ITD in AML and a potential target for FLT3-ITD+ AML patients.

MANF ameliorates DSS-induced mouse colitis via restricting Ly6ChiCX3CR1int macrophage transformation and suppressing CHOP-BATF2 signaling pathway.

Mesencephalic astrocyte-derived neurotrophic factor (MANF), an endoplasmic reticulum stress-inducible secreting protein, has evolutionarily conserved immune-regulatory function that contributes to the negative regulation of inflammation in macrophages. In this study, we investigated the profiles of MANF in the macrophages of the patients with active inflammatory bowel disease (IBD) and the mice with experimental colitis, which was induced in both myeloid cell-specific MANF knockout mice and wild-type mice by 3% dextran sodium sulfate (DSS) for 7 days. We found that MANF expression was significantly increased in intestinal macrophages from both the mice with experimental colitis and patients with active IBD. DSS-induced colitis was exacerbated in myeloid cell-specific MANF knockout mice. Injection of recombinant human MANF (rhMANF, 10 mg·kg-1·d-1, i.v.) from D4 to D6 significantly ameliorated experimental colitis in DSS-treated mice. More importantly, MANF deficiency in myeloid cells resulted in a dramatic increase in the number of Ly6ChiCX3CRint proinflammatory macrophages in colon lamina propria of DSS-treated mice, and the proinflammatory cytokines and chemokines were upregulated as well. Meanwhile, we demonstrated that MANF attenuated Th17-mediated immunopathology by inhibiting BATF2-mediated innate immune response and downregulating CXCL9, CXCL10, CXCL11 and IL-12p40; MANF functioned as a negative regulator in inflammatory macrophages via inhibiting CHOP-BATF2 signaling pathway, thereby protecting against DSS-induced mouse colitis. These results suggest that MANF ameliorates colon injury by negatively regulating inflammatory macrophage transformation, which shed light on a potential therapeutic target for IBD.

Development and validation of a risk prediction score for the severity of acute hypertriglyceridemic pancreatitis in Chinese patients.

BACKGROUND: The frequency of acute hypertriglyceridemic pancreatitis (AHTGP) is increasing worldwide. AHTGP may be associated with a more severe clinical course and greater mortality than pancreatitis caused by other causes. Early identification of patients with severe inclination is essential for clinical decision-making and improving prognosis. Therefore, we first developed and validated a risk prediction score for the severity of AHTGP in Chinese patients. AIM: To develop and validate a risk prediction score for the severity of AHTGP in Chinese patients. METHODS: We performed a retrospective study including 243 patients with AHTGP. Patients were randomly divided into a development cohort (n = 170) and a validation cohort (n = 73). Least absolute shrinkage and selection operator and logistic regression were used to screen 42 potential predictive variables to construct a risk score for the severity of AHTGP. We evaluated the performance of the nomogram and compared it with existing scoring systems. Last, we used the best cutoff value (88.16) for severe acute pancreatitis (SAP) to determine the risk stratification classification. RESULTS: Age, the reduction in apolipoprotein A1 and the presence of pleural effusion were independent risk factors for SAP and were used to construct the nomogram (risk prediction score referred to as AAP). The concordance index of the nomogram in the development and validation groups was 0.930 and 0.928, respectively. Calibration plots demonstrate excellent agreement between the predicted and actual probabilities in SAP patients. The area under the curve of the nomogram (0.929) was better than those of the Bedside Index of Severity in AP (BISAP), Ranson, Acute Physiology and Chronic Health Evaluation (APACHE II), modified computed tomography severity index (MCTSI), and early achievable severity index scores (0.852, 0.825, 0.807, 0.831 and 0.807, respectively). In comparison with these scores, the integrated discrimination improvement and decision curve analysis showed improved accuracy in predicting SAP and better net benefits for clinical decisions. Receiver operating characteristic curve analysis was used to determine risk stratification classification for AHTGP by dividing patients into high-risk and low-risk groups according to the best cutoff value (88.16). The high-risk group (> 88.16) was closely related to the appearance of local and systemic complications, Ranson score ≥ 3, BISAP score ≥ 3, MCTSI score ≥ 4, APACHE II score ≥ 8, C-reactive protein level ≥ 190, and length of hospital stay. CONCLUSION: The nomogram could help identify AHTGP patients who are likely to develop SAP at an early stage, which is of great value in guiding clinical decisions.

Nano-enabled delivery of EGCG ameliorates silica-induced pulmonary fibrosis in rats.

Silicosis is the most serious occupational pulmonary fibrosis caused by excessive inhalation of silica particles, whereas viable therapeutic choices are constrained. Epigallocatechin gallate (EGCG) presents massive health benefits, but unfortunately with stability absence. Here, encapsulation of EGCG in poly(n-butylcyanoacrylate) nanoparticles (EGCG/PBCA-NPs) were fabricated by self-polymerization for gastrointestinal delivery in silicosis fibrosis treatment. The obtained nano-enabled delivery of EGCG was produced using a medical adhesive approved by FDA as carrier, and presented spherical particles with approximate diameter of 160 nm, a narrow PDI value of 0.2, Zeta potential value of 30 mV as well as a high EGCG incorporation (90 %) and loading efficiency (20 %). In evaluating the protect effects of nano-formulations, EGCG/PBCA-NPs shown excellent stability in gastric fluid with pH-triggered release in intestine and strong EGCG gastrointestinal retention against degradation. After daily gastrointestinal administration, EGCG/PBCA-NPs exhibited the superior anti-fibrosis efficacy in silicosis model rats induced by silica, involving lung index decline, hydroxyproline content decrease, histological improvement, collagen accumulation reduction and α-SMA down-regulation in comparison with naked EGCG. These results strongly demonstrated that PBCA-based NPs may be a promising nano-enabled delivery carrier for enhancing the gastrointestinal stability and anti-fibrotic effects of EGCG.

Hepatic paraoxonase 1 ameliorates dysfunctional high-density lipoprotein and atherosclerosis in scavenger receptor class B type I deficient mice.

BACKGROUND: High-density lipoprotein (HDL) plays an antiatherogenic role by mediating reverse cholesterol transport (RCT), antioxidation, anti-inflammation, and endothelial cell protection. Recently, series of evidence have shown that HDL can also convert to proatherogenic HDL under certain circumstances. Plasma paraoxonase 1 (PON1) as an HDL-bound esterase, is responsible for most of the antioxidant properties of HDL. However, whether PON1 can serve as a therapeutic target of dysfunctional HDL-related atherosclerosis remains unclear. METHODS: In this study, scavenger receptor class B type I deficient (Scarb1-/- ) mice were used as the animal model with dysfunctional HDL and increased atherosclerotic susceptibility. Hepatic PON1 overexpression and secretion into circulation were achieved by lentivirus injection through the tail vein. We monitored plasma lipids levels and lipoprotein profiles in Scarb1-/- mice, and measured the levels and activities of proteins associated with HDL function. Meanwhile, lipid deposition in the liver and atherosclerotic lesions was quantified. Hepatic genes relevant to HDL metabolism and inflammation were analyzed. RESULTS: The results showed the relative levels of PON1 in liver and plasma were increased by 1.1-fold and 1.6-fold, respectively, and mean plasma PON1 activity was increased by 63%. High-level PON1 increased the antioxidative and anti-inflammatory properties, promoted HDL maturation and macrophage cholesterol efflux through increasing HDL functional proteins components apolipoprotein A1 (APOA1), apolipoprotein E (APOE), and lecithin-cholesterol acyltransferase (LCAT), while decreased inflammatory protein markers, such as serum amyloid A (SAA), apolipoprotein A4 (APOA4) and alpha 1 antitrypsin (A1AT). Furthermore, hepatic PON1 overexpression linked the effects of antioxidation and anti-inflammation with HDL metabolism regulation mainly through up-regulating liver X receptor alpha (LXRα) and its downstream genes. The pleiotropic effects involved promoting HDL biogenesis by raising the level of APOA1, increasing cholesterol uptake by the liver through the APOE-low density lipoprotein receptor (LDLR) pathway, and increasing cholesterol excretion into the bile, thereby reducing hepatic steatosis and aorta atherosclerosis in Western diet-fed mice. CONCLUSIONS: Our study reveals that high-level PON1 improved dysfunctional HDL and alleviated the development of atherosclerosis in Scarb1-/- mice. It is suggested that PON1 represents a promising target of HDL-based therapeutic strategy for HDL-related atherosclerotic cardiovascular disease.

[Research development of ginkgo terpene lactones].

Ginkgo terpene lactones, as an important active ingredient from Ginkgo leaves, has high medicinal values and has been widely used in clinics. This article would review the researches both at home and abroad, including chemical composition, structure-activity relationship, analytical methods, pharmacological effects, pharmacokinetic characteristics, and so on, providing a reference for further development and utilization of ginkgo terpene lactones.

Biotransformation of ginsenosides F4 and Rg6 in zebrafish.

Ginsenosides F4 and Rg6 (GF4 and GRg6), two main active components of steamed notoginseng or red ginseng, are dehydrated disaccharide saponins. In this work, biotransformation of ginsenosides F4 and Rg6 in zebrafish was investigated by qualitatively identifying their metabolites and then proposing their possible metabolic pathways. The prediction of possible metabolism of ginsenosides F4 and Rg6 using zebrafish model which can effectively simulate existing mammals model was early and quickly performed. Metabolites of ginsenosides F4 and Rg6 after exposing to zebrafish for 24 h were identified by Ultraperformance Liquid Chromatography/Quadrupole-Time-of-Flight Mass Spectrometry. A total of 8 and 6 metabolites of ginsenosides F4 and Rg6 were identified in zebrafish, respectively. Of these, 7 and 5, including M1, M3-M5, M7-M9 and N1 (N5), N2, N4 (N9), N7-N8 were reported for the first time as far as we know. The mechanisms of their biotransformation involved were further deduced to be desugarization, glucuronidation, sulfation, dehydroxylation, loss of C-17 and/or C-23 residue pathways. It was concluded that loss of rhamnose at position C-6 and glucuronidation at position C-3 in zebrafish were considered as the main physiologic and metabolic processes of ginsenosides F4 and ginsenosides Rg6, respectively.

[Identification of saponins from Panax notoginseng in metabolites of rats].

UPLC-QTOF-MS/MS was used to identify metabolites in rat blood, urine and feces after the administration of n-butanol extract derived from steamed notoginseng. The metabolic process of saponins came from steamed notoginseng was analyzed. The metabolites were processed by PeakView software, and identified according to the structural characteristics of prototype compounds and the accurate qualitative and quantitative changes of common metabolic pathways. Four saponins metabolites were identified based on MS/MS information of metabolites, namely ginsenoside Rh4, Rk3, Rk1, Rg5,and their 15 metabolites were verified. The metabolic pathways of the four ginsenosides in n-butanol extract included glucuronidation, desugar, sulfation, dehydromethylation, and branch loss. The metabolites of main active saponin components derived from steamed Panax notoginseng were analyzed from the perspective of qualitative analysis. And the material basis for the efficacy of steamed notoginseng was further clarified.

MicroRNA-20a negatively regulates expression of NLRP3-inflammasome by targeting TXNIP in adjuvant-induced arthritis fibroblast-like synoviocytes.

OBJECTIVES: Rheumatoid arthritis (RA) is a heterogenic and systemic autoimmune disease characterized by synovitis and joint structural damage. However, the pathogenesis of RA is still obscure. It has been reported microRNA-20a (miRNA-20a) was significantly associated with the regulation of pro-inflammatory cytokines release in RA FLS. The purpose of this study was to explore the function and underlying mechanisms of miRNA-20a on NLRP3-inflammasome in adjuvant-induced arthritis (AA) fibroblast-like synoviocytes (FLSs) in vitro. METHODS: In this study, using a combination of Western blotting, Q-PCR, and ELISA analysis, we investigated the influence and function of miRNA-20a on NLRP3-inflammasome by targeting TXNIP in AA FLSs. RESULTS: In the present study, the expression of NLRP3-inflammasome was significant up-regulated in AA model in vitro. Our study indicated that silence of NLRP3 down-regulated the expression of NLRP3-inflammasome and the secretion of IL-1ß and MMP-1. Moreover, over-expression of miR-20a decreased formation of NLRP3-inflammasome, including NLRP3, ASC and caspase-1, and suppressed the secretion of IL-1ß and MMP-1, along with down-regulated the expressions of TXNIP in primary FLSs isolated from AA. With the combined use of prediction programs and luciferase assay, the rat TXNIP mRNA 3'UTR predicted to be targeted by miR-20a. Similarly, inhibitor TXNIP expression by TXNIP-siRNA markedly repressed formation of NLRP3-inflammasome and the secretion of IL-1ß and MMP-1. CONCLUSION: Taken together, these results indicate that miR-20a may play a pivotal role in the NLRP3-inflammasome by targeted inhibit TXNIP expression in AA FLSs.

G5-PEG PAMAM dendrimer incorporating nanostructured lipid carriers enhance oral bioavailability and plasma lipid-lowering effect of probucol.

This work aimed to improve the oral bioavailability and plasma lipid-lowering effect of probucol (PB) by constructing a combined drug delivery system (CDDS) composed of nanostructured lipid carrier (NLC) and PEGylated poly(amidoamine) dendrimer (PEG-PAMAM). PEG-PAMAM with dendrimer generations of 5 (G5-PEG) or 7 (G7-PEG) were incorporated in PB-NLCs to form PB-CDDSs, PB-NLCs/G5-PEG and PB-NLCs/G7-PEG. The resultant two kinds of PB-CDDSs were characterized by particle size, zeta potential, drug encapsulation efficacy, PB release rates, and physical stability. Formulation effects of NLC and CDDS on the cellular uptake of hydrophobic drug were explored in Caco-2 cells by fluorescent Cy5 dye as a hydrophobic drug model. Furthermore, in vivo pharmacokinetics of the PB-CDDS composed of G5-PEG and PB-NLCs were investigated in a low density lipoprotein receptor knockout (LDLr-/-) mouse model, including plateau plasma PB concentrations after oral administration of multiple doses, and bioavailability after oral administration of a single dose of different PB formulations. In addition, lipid-lowering effect of PB-NLCs/G5-PEG was studied. The results indicate that both G5-PEG and G7-PEG significantly improved aqueous solubility of PB. The two PB-CDDSs exhibited similar particle size (around 150nm) as PB-NLCs, but slower PB burst release rate, higher total PB release amount, and better particle morphology and storage stability than PB-NLCs. In comparison with traditional NLC, CDDS dramatically enhanced cellular uptake of Cy5 into Caco-2 cells. In vivo results demonstrate that PB-NLCs/G5-PEG had the highest plateau plasma PB concentration and oral bioavailability, and the greatest cholesterol-lowering effect in comparison with PB suspensions and PB-NLCs. Therefore, G5-PEG incorporating NLC can be exploited as a promising drug delivery system to improve oral bioavailability and lipid-lowering effect of PB.

Lipopolysaccharide/adenosine triphosphate induces IL­1ß and IL-18 secretion through the NLRP3 inflammasome in RAW264.7 murine macrophage cells.

The NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome plays pivotal roles in inflammation and autoimmunity. The NLRP3 inflammasome is activated in response to various signals, including pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs). However, its role in inflammation remains unclear. In this study, we used lipopolysaccharide (LPS) and adenosine triphosphate (ATP) to simulate an inflammatory environment as the testing model. We found that the exposure of RAW264.7 cells to LPS/ATP triggered the activation of caspase-1 (P<0.01) and the cleavage of interleukin (IL)-1ß (P<0.01), as well as the release of other cytokines, such as IL-18 (P<0.01) and IL-33 (P<0.01). Extracellular potassium chloride at a high concentration (150 mM) abrogated the secretion of IL-1ß and IL-18 (P<0.01), but did not reduce the processing of IL-33 (P>0.05). In addition, the silencing of NLRP3 with small interfering RNA (siRNA) suppressed the generation of proinflammatory cytokines, such as IL-1ß (P<0.01), IL-18 (P<0.01), but not IL-33 (P>0.05), along with the decreased mRNA and protein expression of NLRP3 and caspase-1 (P<0.05). However, extracellular potassium at a high concentration and NLRP3 siRNA did not affect the level of apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD) (ASC; P>0.05). Our results suggest that the NLRP3/ASC/caspase-1 axis participates in the regulation of pro-imflammatory cytokine secretion in RAW264.7 cells, particularly the generation of IL-1ß and IL-18.

Long-term use of methamphetamine disrupts the menstrual cycles and hypothalamic-pituitary-ovarian axis.

OBJECTIVES: Long-term use of methamphetamine (MA) induces the neuron damage and leads to multiple neuropsychiatric disorders. However, the effect of MA on the female reproductive functions has not yet been evaluated. The objective of this study was to determine the prevalence of abnormal menstrual cycling in female MA users. METHODS: Female MA users (N = 113) were recruited from the Zhangjiang Isolated Compulsory Detoxification Center. Gynecologic history and drug use history were recorded, and serum levels of follicle-stimulating hormone, luteinizing hormone, prolactin, estrogen, progesterone, and testosterone were measured. RESULTS: Long-term use of MA significantly altered the menstrual cycle, and 33.6% women suffered from abnormal uterine bleeding while using MA. Deregulation of sex hormones was observed in 73.3% of participants during abstinence. The most common patterns were simple anovular menstruation, which was caused mainly by a hypothalamic deregulation and pituitary suppression with or without ovarian suppression. Normal hormone levels were observed more frequently in participants abstinent for more than 10 months (39.5%) than in participants who were abstinent for less than 10 months (18.6%). However, no relationship was found between hormone deregulation and age or history of MA use. CONCLUSIONS: The present data demonstrate that long-term use of MA results in the disruption of menstrual cycles and dysfunction of hypothalamic-pituitary-gonadal axis in women.

The relationship between obesity and diabetic nephropathy in China.

BACKGROUND: The epidemic of diabetic nephropathy (DN) has been paralleled by rapid increases in both obesity and diabetes in China. The aim of this study was to investigate the natural history of DN and the association of obesity and renal function with diabetes. METHODS: In total, 264 patients with renal biopsy-confirmed DN were examined from 2002 to 2008 and followed up to June 2008 in our institute. Among these, 129 patients were classified into a Kidney Disease Outcomes Quality Initiative (K/DOQI) stage I subgroup. Weight status, clinico-histopathological features, the development of end-stage renal disease (ESRD) and increased proteinuria were evaluated at the baseline of biopsy and during the follow up. Lean, overweight and obese phenotypes were defined as body mass index (BMI) less than 25 kg/m2, 25-28 kg/m2, and more than 28 kg/m2 over, respectively. RESULTS: In the patients with renal biopsy-confirmed DN, BMI was 25.5 ± 3.39 kg/m2, with 122 (46.2%), 83 (31.4%) and 59 (22.3%) having lean, overweight and obese phenotypes, respectively. Mean proteinuria was 3.09 ± 2.32 g/24 h, serum creatinine was 2.02 ± 2.02 mg/dL, and creatinine clearance rate (Ccr) was 96.0 ± 54.0 mL/min/1.73 m2. Compared with obese patients, lean patients had a lower Ccr, a higher percentage of anemia, more renal lesions and higher risk for ESRD (HR = 1.812, P = 0.048). The weight in obese patients decreased significantly after 27 months, and lean patients had a longer duration of diabetes than obese patients. Regarding patients at K/DOQI stage I, patients with DN showed similar duration of diabetes regardless of weight status. Minimal weight loss was recorded in obese patients during follow-up, and they exhibited greater glomerular hyperfiltration and higher risk for increased proteinuria (HR = 2.872, P = 0.014) than lean patients. CONCLUSIONS: In China, obesity is common in DN patients undergoing biopsy. Initial high levels of proteinuria and subsequent weight loss are the major characteristics of the natural course of DN. Obesity contributed to increased proteinuria at an early stage, while the lean phenotype was associated with ESRD development, especially at the later stages.

Obesity-related glomerulopathy: body mass index and proteinuria.

BACKGROUND AND OBJECTIVES: Obesity-related glomerulopathy (ORG) is an increasing cause of end-stage renal disease, but evidence concerning the effects of treatments is rather limited. This study was aimed at exploring the renoprotective effects of weight loss on patients with ORG. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A total of 63 patients with renal biopsy-proven ORG had food and exercise intervention in the physician-supervised weight loss program and were divided into three groups on the basis of the percentage of weight change from baseline to follow-up: significant weight loss (>3% reduction in body mass index [BMI]), stable weight, or significant weight gain (>3% increase). Metabolic parameters and renal lesions were evaluated regularly for 2 years. RESULTS: After 6 months, 27 patients lost weight by 8.29 +/- 4.00%, with a mean decrease in proteinuria of 35.3%, whereas 24 months later, 27 patients achieved a 9.20 +/- 3.78% reduction in BMI and a 51.33% reduction in urine protein secretion. The levels of serum triglyceride, serum uric acid, and BP were also decreased. Contrarily, in patients with increased BMI, urine protein was increased by 28.78%. Correlation analysis showed proteinuria was associated with BMI, serum triglyceride, and uric acid, and multivariate regression analysis indicated the changes in BMI were the only predictor of proteinuria (P < 0.01). CONCLUSIONS: Weight loss intervention benefited remission of proteinuria in patients with ORG, whose function could not be replaced by conventional pharmacotherapy.

SnO2@Poly(HEMA-co-St-co-VPBA) core-shell nanoparticles designed for selectively enriching glycopeptides followed by MALDI-MS analysis.

The core-shell boronic-acid functionalized nanoparticles SnO(2)@Poly(HEMA-co-St-co-VPBA) are designed for selectively enriching glycopeptides, followed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Such 60 nm sized core-shell nanoparticles are prepared by means of copolymerization between 2-hydroxyethyl methacrylate (HEMA) grafted on SnO(2) nanoparticles, styrene, and 4-vinylphenylboronic acid (VPBA). All of the synthesis procedures are completed within 3 h. Cyclic boronate esters form between boronic-acid groups on the polymer chains and cis-diol groups on glycopeptides, and thus almost all intact glycopeptides from low-abundant horseradish peroxidase (HRP) and bovine asialofetuin (ASF) are enriched with high selectivity and efficiency. After enrichment, both intact N- and O-glycopeptides are characterized by multistage MS. Furthermore, we successfully apply this method to the human serum sample for characterizing the target glycoproteins haptoglobin and alpha-1-acid-glycoprotein. The present selective enriching method followed by multistage-MS analysis is proven to be a good choice for routine glycopeptide characterization.

Homo-binding character of LMO2 isoforms and their both synergic and antagonistic functions in regulating hematopoietic-related target genes.

BACKGROUND: The human lmo2 gene plays important roles in hematopoiesis and is associated with acute T lymphocyte leukemia. The gene encodes two protein isoforms, a longer form LMO2-L and a shorter form LMO2-S. Both isoforms function as bridge molecules to assemble their partners together to regulate their target genes. A typical LMO2 binding site consists of two elements, a GATA site and an E-box, with an interval of 9 approximately 12 bp. METHODS: In this study, the combination of MBP pulldown assay and mammalian two hybrid assay were used to confirm the homo-binding character of LMO2-L/-S isoforms. Luciferase reporter assay and Real-time PCR assay were used to detect expression levels and relative promoter activities of LMO2-L/-S isoforms. Co-transfection and Luciferase reporter assay were used to reveal the detailed regulatory pattern of LMO2-L/-S isoforms on their targets. RESULTS: Herein we report the homo-interaction character of LMO2-L and LMO2-S and their major difference in manner of regulating their target genes. Our results showed that LMO2-L and LMO2-S could only bind to themselves but not each other. It was also demonstrated that LMO2-L could either positively or negatively regulate the transcription of its different target genes, depending on the arrangement and strand location of the two elements GATA site and E-box, LMO2-S, however, performed constitutively transcriptional inhibiting function on all target genes. CONCLUSION: These results suggest that LMO2 isoforms have independent functions while there is no interaction between each other and they could play synergetic or antagonistic roles precisely in regulating their different genes involved in normal and aberrant hematopoiesis.