Development and Validation of a Simple, Fast, and Accessible HPLC-UV Method for Cannabinoids Determination in Cannabis sativa L. Extracts and Medicinal Oils.

INTRODUCTION: Cannabis sativa L. is a well-recognized medicinal plant. Cannabis regulations in Argentina are insufficient to solve the problem of patient access to full-spectrum cannabis-based products. So, the market of artisanal products with unknown quality and dosage of cannabinoids is increasing, and so is the local demand and need for analyzing these products. However, much of the latest validated methodologies for cannabinoid quantification include expensive instrumentation that is not always available in laboratories of health institutions in Argentina. METHODS: The aim of this work was to develop and validate a simple and rapid HPLC-UV method for the identification and quantification of principal cannabinoids in cannabis resins, inflorescences, and medicinal oils using standard HPLC equipment. The cannabinoids selected for validation were cannabidiol acid (CBDA), cannabigerol (CBG), cannabidiol (CBD), cannabinol (CBN), delta-9-tetrahydrocannabinol (Δ9-THC), cannabichromene (CBC), and tetrahydrocannabinol acid (THCA). A method for the simultaneous identification and quantification of these 7 main cannabinoids was developed and then validated. Some data parameters were comparable to other reports with more sophisticated analytical instruments for the analysis of cannabis. The assessed limits of detection and the limits of quantitation ranged from 0.9 to 3.66 µg/mL and 2.78 to 11.09 µg/mL, respectively. The concentration-response relationship of the method indicated a linear relationship between the concentration and peak area with R2 values of > 0.99 for all 7 cannabinoids. RESULTS: The relative standard deviation (RSD%) varied from 2.34 to 4.82 for intraday repeatability and from 1.16 to 3.15 for interday repeatability. The percentage of recovery values was between 94 to 115% (resins) and 80 to 103% (inflorescence extract). The cannabis industry is growing rapidly, and there is a need for reliable testing methods to ensure the safety and efficacy of cannabis products. In addition, current methods for cannabinoid analysis are often time-consuming and expensive, while the HPLC-UV method herein reported is a simple, rapid, accurate, and cost-effective alternative for the analysis of cannabinoids in cannabis resins, inflorescences, and medicinal oils. CONCLUSION: This method will be proposed to be included in the Cannabis sativa L. monograph of the Argentine Pharmacopoeia.

Granulocyte-colony stimulating factor in acute-on-chronic liver failure: Systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIMS: A dysfunctional immune response is key to the pathogenesis of acute-on-chronic liver failure (ACLF). It has been suggested that treatment with granulocyte colony-stimulating factor (G-CSF) increases survival in patients with ACLF by improving immune cell dysfunction and promoting liver regeneration. The aim of the study is to evaluate the survival benefit associated with G-CSF administration compared with standard medical therapy (SMT) in ACLF. METHODS: Systematic review and meta-analysis of randomized controlled trials. The primary outcome was survival at 60-90 days. We searched Ovid Medline, EMBASE, and Cochrane Central Register of Controlled Trials from inception to August 2021. Manual searches of reference lists in relevant articles and conference proceedings were also included. The revised Cochrane risk-of-bias tool was used for quality and risk of bias assessment. Two independent investigators extracted the data, and disagreements were solved by a third collaborator. RESULTS: The initial search identified 142 studies. Four randomized controlled trials were selected for quantitative analysis including 310 patients (154 G-CSF and 156 SMT). Significant heterogeneity was observed (I2=74%, Chi2=11.57, p=0.009). G-CSF administration did not improve survival in patients with ACLF (random-effects model, risk ratio=0.64 [95% CI 0.39, 1.07]). However, when considering only the results from the studies performed in Asia, a significant decrease on mortality was observed (risk ratio=0.53 [95% CI 0.35, 0.81]). Severity scores (MELD and Child) and CD34+ peripheral cells mobilization did not significantly improve with G-CSF. CONCLUSION: In a systematic review and meta-analysis, G-CSF administration did not significantly improve overall survival compared to SMT in patients with ACLF. The beneficial effects observed in Asian studies, as opposed to the European region, suggest that specific populations may benefit from further research aiming to identify certain subgroups with favourable outcomes when using G-CSF.

Endoscopist-directed propofol is more efficient than anesthesiologist-administered propofol in patients at low-intermediate anesthetic risk.

OBJECTIVE: Endoscopist-directed propofol (EDP) sedation is becoming more popular, with a reported safety and efficacy similar to anesthesiologist-administered propofol (AAP). The aim of this study is to compare the efficiency of EDP and AAP in patients of low-intermediate anesthetic risk. METHODS: A prospective cost-effectiveness comparison study was conducted. The costs of the endoscopic procedures in the EDP and AAP group were calculated using the full cost methodology after breaking down the endoscopic activity into relative value units to allocate costs in an equitable way. To determine the effectiveness, adverse events related to endoscopic sedation and the number of incomplete procedures were registered for the EDP group and compared with those published by anesthesiologists for AAP. RESULTS: A total of 1165 and 18 919 endoscopic procedures were, respectively, included in the EDP and AAP groups. The average costs of EDP vs. AAP for gastroscopy, colonoscopy and endoscopic ultrasound were &OV0556; 182.81 vs. &OV0556; 332.93, &OV0556; 297.07 vs. &OV0556; 459.76, and &OV0556; 319.92 vs. &OV0556; 485.12, respectively. No significant differences were detected regarding the rate of overall adverse events (4.43 vs. 4.46%) or serious adverse events (0 vs. 0.17%); the rate of arterial hypotension was significantly lower in the EDP group: 0.34 vs. 1.78% [odds ratio (OR), 0.19; 95% confidence interval (CI), 0.08-0.46] and the desaturation rate was significantly lower in the AAP group: 3.26 vs. 1.29% (OR, 2.58; 95% CI, 1.85-3.60). No significant differences were found in terms of incomplete examinations (0.17 vs. 0.14%). CONCLUSION: In patients with low-intermediate anesthetic risk referred for an endoscopic examination, EDP appears to be more efficient than AAP.

RECQL5: Another DNA helicase potentially involved in hereditary breast cancer susceptibility.

There is still around 50% of the familial breast cancer (BC) cases with an undefined genetic cause, here we have used next-generation sequencing (NGS) technology to identify new BC susceptibility genes. This approach has led to the identification of RECQL5, a member of RECQL-helicases family, as a new BC susceptibility candidate, which deserves further study. We have used a combination of whole exome sequencing in a family negative for mutations in BRCA1/2 throughout (BRCAX), in which we found a probably deleterious variant in RECQL5, and targeted NGS of the complete coding regions and exon-intron boundaries of the candidate gene in 699 BC Spanish BRCAX families and 665 controls. Functional characterization and in silico inference of pathogenicity were performed to evaluate the deleterious effect of detected variants. We found at least seven deleterious or likely deleterious variants among the cases and only one in controls. These results prompt us to propose RECQL5 as a gene that would be worth to analyze in larger studies to explore its possible implication in BC susceptibility.

Genomic characterization of individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced lung cancer.

Single nucleotide polymorphisms (SNPs) may modulate individual susceptibility to carcinogens. We designed a genome-wide association study to characterize individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced non-small cell lung cancer (NSCLC), and we validated our results. We hypothesized that this strategy would enrich the frequencies of the alleles that contribute to the observed traits. We genotyped 2.37 million SNPs in 95 extreme phenotype individuals, that is: heavy smokers that either developed NSCLC at an early age (extreme cases); or did not present NSCLC at an advanced age (extreme controls), selected from a discovery set (n = 3631). We validated significant SNPs in 133 additional subjects with extreme phenotypes selected from databases including >39,000 individuals. Two SNPs were validated: rs12660420 (pcombined  = 5.66 × 10-5 ; ORcombined  = 2.80), mapping to a noncoding transcript exon of PDE10A; and rs6835978 (pcombined  = 1.02 × 10-4 ; ORcombined  = 2.57), an intronic variant in ATP10D. We assessed the relevance of both proteins in early-stage NSCLC. PDE10A and ATP10DmRNA expressions correlated with survival in 821 stage I-II NSCLC patients (p = 0.01 and p < 0.0001). PDE10A protein expression correlated with survival in 149 patients with stage I-II NSCLC (p = 0.002). In conclusion, we validated two variants associated with extreme phenotypes of high and low risk of developing tobacco-induced NSCLC. Our findings may allow to identify individuals presenting high and low risk to develop tobacco-induced NSCLC and to characterize molecular mechanisms of carcinogenesis and resistance to develop NSCLC.

Polyphenol-Rich Fraction from Larrea divaricata and its Main Flavonoid Quercetin-3-Methyl Ether Induce Apoptosis in Lymphoma Cells Through Nitrosative Stress.

Larrea divaricata is a plant with antiproliferative principles. We have previously identified the flavonoid quercetin-3-methyl ether (Q-3-ME) in an ethyl acetate fraction (EA). Both the extract and Q-3-ME were found to be effective against the EL-4 T lymphoma cell line. However, the mechanism underlying the inhibition of tumor cell proliferation remains to be elucidated. In this work, we analyzed the role of nitric oxide (NO) in the induction of apoptosis mediated by Q-3-ME and EA. Both treatments were able to induce apoptosis in a concentration-dependent and time-dependent manner. The western blot analysis revealed a sequential activation of caspases-9 and 3, followed by poly-(ADP-ribose)-polymerase cleavage. EA and Q-3-ME lowered the mitochondrial membrane potential, showing the activation of the intrinsic pathway of apoptosis. Q-3-ME and EA increased NO production and inducible NO synthase expression in tumor cells. The involvement of NO in cell death was confirmed by the nitric oxide synthases inhibitor L-NAME. In addition, EA and Q-3-ME induced a cell cycle arrest in G0/G1 phase. These drugs did not affect normal cell viability. This data suggested that EA and Q-3-ME induce an increase in NO production that would lead to the cell cycle arrest and the activation of the intrinsic pathway of apoptosis. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacological mechanism underlying the antinociceptive activity of vanillic acid.

Vanillic acid is found at high concentrations in many plants used in traditional medicine. It has been associated with a variety of pharmacologic activities such as carcinogenesis inhibition, apoptosis and inflammation; however, it has become most popular for its pleasant creamy odor. Since there are few reports concerning the antinociceptive activity of this phenolic compound, the aim of this work was to study this activity in in vivo animal models. Vanillic acid was administered by the intraperitoneal route producing a dose-dependent inhibition of the acetic acid-induced writhing response (ED50: 9.3mg/kg). The antinociceptive activity was inhibited by the pretreatment with ondansetron and yohimbine, indicating that the serotoninergic and adrenergic systems could participate in the mechanism underlying the analgesic activity of vanillic acid. This compound was also demonstrated to interact with ASICs (Acid-sensing Ion Channels) as well as with TPRV1, TRPA1, and TRPM8 receptors in vivo. Furthermore, vanillic acid did not interfere with the locomotor function or motor coordination. The plasmatic phenolic content, analyzed by HPLC, showed that its t1/2 and AUC were 0.123h and 1.38µg·h/mL; respectively. In conclusion, vanillic acid might represent a potential therapeutic option for the treatment of pain.

Standard versus continuous administration of capecitabine in metastatic breast cancer (GEICAM/2009-05): a randomized, noninferiority phase II trial with a pharmacogenetic analysis.

BACKGROUND: The approved capecitabine regimen as monotherapy in metastatic breast cancer (MBC) is 1,250 mg/m(2) twice daily for 2 weeks on and 1 week off (Cint). Dose modifications are often required because of severe hand-foot syndrome (HFS). We tested a continuous regimen with a lower daily dose but a similar cumulative dose in an attempt to reduce the severity of adverse events (AEs) while maintaining efficacy. METHODS: We randomized 195 patients with HER-2/neu-negative MBC to capecitabine 800 mg/m(2) twice daily throughout the 21-day cycle (Ccont) or to Cint to assess noninferiority in the percentage of patients free of progression at 1 year. Secondary endpoints included efficacy and safety. Associations between polymorphisms in capecitabine metabolism-related genes and drug response were assessed. RESULTS: The percentage of patients free of progression at 1 year was 27.3% with Cint versus 25.3% with Ccont (difference of -2.0%; 95% confidence interval: -15.5% to 11.5%, exceeding the 15% deemed noninferior). Differences regarding other efficacy variables were also not found. Grade 3-4 HFS was the most frequent AE (41.1% in Cint vs. 42.3% in Ccont). Grade 3-4 neutropenia, thrombocytopenia, diarrhea, and stomatitis were more frequent with Cint. A 5' untranslated region polymorphism in the carboxylesterase 2 gene was associated with HFS. One polymorphism in cytidine deaminase and two in thymidine phosphorylase were associated with survival. CONCLUSION: Our study was unable to show noninferiority with the continuous capecitabine regimen (Ccont) compared with the approved intermittent regimen (Cint). Further investigation is required to improve HFS. Polymorphisms in several genes might contribute to interindividual differences in response to capecitabine.

DNA glycosylases involved in base excision repair may be associated with cancer risk in BRCA1 and BRCA2 mutation carriers.

Single Nucleotide Polymorphisms (SNPs) in genes involved in the DNA Base Excision Repair (BER) pathway could be associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between one of the components of the BER pathway, PARP1 (poly ADP ribose polymerase), and both BRCA1 and BRCA2. In the present study, we have performed a comprehensive analysis of 18 genes involved in BER using a tagging SNP approach in a large series of BRCA1 and BRCA2 mutation carriers. 144 SNPs were analyzed in a two stage study involving 23,463 carriers from the CIMBA consortium (the Consortium of Investigators of Modifiers of BRCA1 and BRCA2). Eleven SNPs showed evidence of association with breast and/or ovarian cancer at p<0.05 in the combined analysis. Four of the five genes for which strongest evidence of association was observed were DNA glycosylases. The strongest evidence was for rs1466785 in the NEIL2 (endonuclease VIII-like 2) gene (HR: 1.09, 95% CI (1.03-1.16), p = 2.7 × 10(-3)) for association with breast cancer risk in BRCA2 mutation carriers, and rs2304277 in the OGG1 (8-guanine DNA glycosylase) gene, with ovarian cancer risk in BRCA1 mutation carriers (HR: 1.12 95%CI: 1.03-1.21, p = 4.8 × 10(-3)). DNA glycosylases involved in the first steps of the BER pathway may be associated with cancer risk in BRCA1/2 mutation carriers and should be more comprehensively studied.

Identification of genetic variants associated with capecitabine-induced hand-foot syndrome through integration of patient and cell line genomic analyses.

OBJECTIVE: A primary challenge in identifying replicable pharmacogenomic markers from clinical genomewide association study (GWAS) trials in oncology is the difficulty in performing a second large clinical trial with the same drugs and dosage regimen. We sought to overcome this challenge by incorporating GWAS results from cell-based studies using the same chemotherapy as a clinical cohort. METHODS: In this study, we test whether the overlap between genetic variants identified in a preclinical study and a clinical study on capecitabine is more than expected by chance. A GWAS of capecitabine-induced cytotoxicity was performed in 164 lymphoblastoid cell lines derived from the CEU HapMap population and compared with a GWAS of hand-foot syndrome (HFS), the most frequent capecitabine-induced adverse drug reaction, in Spanish breast and colorectal cancer patients (n=160) treated with capecitabine. RESULTS: We observed an overlap of 16 single nucleotide polymorphisms associated with capecitabine-induced cytotoxicity (P<0.001) in lymphoblastoid cell lines and HFS (P<0.05) in patients, which is a greater overlap than expected by chance (genotype-phenotype permutation empirical P=0.015). Ten tag single nucleotide polymorphisms, which cover the overlap loci, were genotyped in a second patient cohort (n=85) and one of them, rs9936750, was associated with capecitabine-induced HFS (P=0.0076). CONCLUSION: The enrichment results imply that cellular models of capecitabine-induced cytotoxicity may capture components of the underlying polygenic architecture of related toxicities in patients.

A fraction containing kaempferol-3,4'-dimethylether from Larrea divaricata Cav. induces macrophage activation on mice infected with Candida albicans.

Larrea divaricata Cav. is a plant growing in South America. Both the infusion and a derived fraction (F1) of L. divaricata have proved to have immunomodulatory properties. Moreover, F1 can activate macrophages obtained from mice infected with Candida albicans. In this work, F1 was administrated to infected animals, and the state and type of activation of resident macrophages were studied. Results showed that F1 was able to activate macrophages obtained from infected mice by both classical and alternative pathways, probably by inducing a translocation of nuclear factor kappa-B. F1 increases not only the lysosomal activity of macrophages but also the production of phagosomal superoxide anion as a consequence of the activation of the Nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) complex. F1 induced an increase in the macrophage capacity to kill the fungus, which was reflected in a decrease in the levels of colonization of organs. A main flavonoid, kaempferol-3,4'-dimethylether, was identified in F1 by HPLC. This compound increased in vitro production of nitric oxide in heat-killed C. albicans-stimulated macrophages. The flavonoid could thus be considered one of the responsible molecules mediating the overall effects of F1 on the immune system in infected animals.

A fraction rich in phenyl propanoids from L. divaricata aqueous extract is capable of inducing apoptosis, in relation to H2O2 modulation, on a murine lymphoma cell line.

Leukemia and lymphoma are a group of heterogeneous neoplastic disorder of white blood cells characterized by the uncontrolled proliferation and block in differentiation of hematopoietic cells. Nowadays, there is an interest in therapy with drugs of plant origin because conventional medicine can be inefficient or also results in side effects. Larrea divaricata Cav., is a plant widely distributed in Argentina that possess antiproliferative and antioxidant activities reported. Nordihydroguaiaretic acid (NDGA) was previously found in the plant and related to both antiproliferative and pro-proliferative actions on a lymphoma cell line. In order to demonstrate whether the presence of NDGA may be beneficial or not in the antiproliferative action of the aqueous extract, the extract of L. divaricata was submitted to a fractionation and fractions with and without NDGA were studied in a murine lymphocitic leukemia cell line (EL-4) proliferation. The effect of the most active fraction was studied in relation to H2O2 modulation and the synergistic action between compounds, found in fractions, was analyzed. The presence of NDGA was not a detonator for pro-proliferative action and its presence could be beneficial in low concentrations allowing a synergist antiproliferative action with other compounds.

Efficacy and safety of ERCP in a low-volume hospital.

BACKGROUND AND AIMS: there is little scientific evidence on the outcomes of endoscopic retrograde cholangiopancreatography (ERCP) performed in low-volume hospitals; however, in our country, it is growing up its implementation. The objectives of our study were to evaluate the efficacy and safety of this technique performed by two endoscopists with basic training in a center of this nature and analyze the learning curve in the first procedures. PATIENTS AND METHODS: single-center retrospective study of the first 200 ERCP performed in our hospital (analyzing the evolution between the first 100 and 100 following procedures), comparing them with the quality standards proposed in the literature. RESULTS: from February 2009 to April 2011, we performed 200 ERCP in 169 patients, and the most common indications were: Choledocholithiasis (77 %), tumors (14.5 %) and other conditions (8.5 %). The cannulation rate rose from 85 % in the first 100 ERCPto 89 % in the next 100 procedures, clinical success from 81 % to 87 %, decreasing the post-ERCP acute pancreatitis rate from 11 % to 4 %, upper gastrointestinal bleeding (UGIB) from 3 % to 2 % and acute cholangitis from 4 % to 1 %. There was a death from a massive UGIB in a cirrhotic patient in the first group of patients and a case of biliary perforation resolved by surgery in the second one. CONCLUSIONS: the results obtained after performing 200 procedures support the ability to practice ERCP in low-volume hospitals obtaining levels of efficacy and safety in accordance with published quality standards.

Macrophages activation by a purified fraction, free of nordihydroguaiaretic acid (NDGA), from Larrea divaricata Cav. as a potential novel therapy against Candida albicans.

Larrea divaricata Cav. (jarilla) is a plant with well-documented applications in Argentinean folk medicine. In order to determine if the treatment with a purified fraction named F1 was capable to maintain a state of priming of macrophages after 15 days of mice infection with Candida albicans. Infected and uninfected mice were used. The effect of F1 on: cytosolic protein levels, apoptosis, phagocytosis, reactive oxygen species production, nitric oxide (NO), cell activity, lysosomal activity and the tissue fungal burden were studied. The results showed that F1 increased macrophages yeast phagocytosis and reactive oxygen species and NO production. All these effects were related to a decrease of cell activity and possible apoptosis. In conclusion, it was observed that F1 could induce a state of long-term activation of macrophages, since we observed increased activity of macrophages 15 days after infection, and it could be related to the elimination of C. albicans. These data may suggest that F1 fraction could be useful against disseminated candidiasis in patients and further studies on this field are desirable.

Chemical study and anti-inflammatory activity of Capsicum chacoense and C. baccatum

Capsicum species, Solanaceae, have been used for centuries as food additives by populations of different regions of the world. Capsaicin (trans-methyl-N-vainillyl-nonenamide) is the main pungent compound extracted from the red hot pepper fruit (Capsicum spp.). The capsaicin content was determined by means of a HPLC method. The results showed that Capsicum chacoense Hunz., contains similar amounts of capsaicin (13.9 mg/100 g of dry fruit) in comparison with Capsicum baccatum L. (12.6 mg/100 g) and Capsicum annum L. (10.1 mg/100 g). Dichloromethane (CH2Cl2) and ethanol (EtOH) extracts of C. chacoense elicited a 46% and 38 % of inhibition on the arachidonic acid (AA) pathway in ear edema respectively while the CH2Cl2 and EtOH extracts of C. baccatum inhibited 52% and 35% the arachidonic acid response respectively.

Genetic polymorphisms among C57BL/6 mouse inbred strains.

Mice from the inbred C57BL/6 strain have been commonly used for the generation and analysis of transgenic and knockout animal models. However, several C57BL/6 substrains exist, and these are genetically and phenotypically different. In addition, each of these substrains can be purchased from different animal providers and, in some cases, they have maintained their breeding stocks separated for a long time, allowing genetic differences to accumulate due to individual variability and genetic drift. With the aim of describing the differences in the genotype of several C57BL/6 substrains, we applied the Illumina(®) Mouse Medium Density Linkage Mapping panel, with 1,449 single nucleotide polymorphisms (SNPs), to individuals from ten C57BL/6-related strains: C57BL/6JArc, C57BL/6J from The Jackson Lab, C57BL/6J from Crl, C57BL6/JRccHsd, C57BL/6JOlaHsd, C57BL/6JBomTac, B6(Cg)-Tyr ( c-2j )/J, C57BL/6NCrl, C57BL/6NHsd and C57BL/6NTac. Twelve SNPs were found informative to discriminate among the mouse strains considered. Mice derived from the original C57BL/6J: C57BL/6JArc, C57BL/6J from The Jackson Lab and C57BL/6J from Crl, were indistinguishable. Similarly, all C57BL/6N substrains displayed the same genotype, whereas the additional substrains showed intermediate cases with substrain-specific polymorphisms. These results will be instrumental for the correct genetic monitoring and appropriate mouse colony handling of different transgenic and knockout mice produced in distinct C57BL/6 inbred substrains.

'In vivo' and 'in vitro' activity of Larrea divaricata Cav. on EL-4 cells.

Larrea divaricata is a plant widely used in folk medicine in Argentina. It has been demonstrated that an aqueous extract of L. divaricata possesses a biphasic effect on cell proliferation, at low concentrations exerts a stimulatory action and at high concentrations exerts anti-proliferative effects upon the T lymphoma BW 5147; therefore, we propose in this paper to test the effect of the extract 'in vitro' and 'in vivo' in another T-cell lymphoma named EL-4. It was analyzed 'in vitro' cell proliferation by tritiated thymidine uptake and the effect of the extract on tumors induced in mice analyzing tumor progression and survival.The results showed that the aqueous extract induced the proliferation of tumor cells at all the concentrations studied. The results 'in vivo' showed that the aqueous extract stimulated significantly the size of tumors and that untreated mice lived longer than those treated. It is important to be very careful when plant extracts are selected for the treatment of several diseases. Consequently, before using a plant extract, specific scientific studies must be undertaken on different models to certificate therapeutic and adverse effects. Moreover, it can be said that L. divaricata has a specific anti-tumor mechanism of action depending on the targets.

A pivotal role of the basic leucine zipper transcription factor bZIP53 in the regulation of Arabidopsis seed maturation gene expression based on heterodimerization and protein complex formation.

Transcription of Arabidopsis thaliana seed maturation (MAT) genes is controlled by members of several transcription factor families, such as basic leucine zippers (bZIPs), B3s, MYBs, and DOFs. In this work, we identify Arabidopsis bZIP53 as a novel transcriptional regulator of MAT genes. bZIP53 expression in developing seeds precedes and overlaps that of its target genes. Gain- and loss-of-function approaches indicate a correlation between the amount of bZIP53 protein and MAT gene expression. Specific in vivo and in vitro binding of bZIP53 protein to a G-box element in the albumin 2S2 promoter is demonstrated. Importantly, heterodimerization with bZIP10 or bZIP25, previously described bZIP regulators of MAT gene expression, significantly enhances DNA binding activity and produces a synergistic increase in target gene activation. Full-level target gene activation is strongly correlated with the ratio of the correspondent bZIP heterodimerization partners. Whereas bZIP53 does not interact with ABI3, a crucial transcriptional regulator in Arabidopsis seeds, ternary complex formation between the bZIP heterodimers and ABI3 increases the expression of MAT genes in planta. We therefore propose that heterodimers containing bZIP53 participate in enhanceosome formation to produce a dramatic increase in MAT gene transcription.