Interaction between polymorphisms in SLC6A4 and BDNF on major depressive disorder in a sample of the argentinean population / Interacción entre polimorfismos en SLC6A4 y BDNF en el trastorno depresivo mayor en una muestra de la población argentina

The dysfunction in the serotoninergic neurotransmission has been classically associated with major depressive disorder (MDD); however, other pathways and processes seem to have a role in this illness, such as neurogenesis and related molecules: the Brain-Derived Neurotrophic Factor (BDNF) and the Apolipoprotein E (APOE). There are many reports that indicate an association between certain polymorphism in these genes and MDD. The aim of our study was to analyze the possible association between MDD and polymorphisms in HTR2A (5-hydroxytryptamine receptor 2A), BDNF and APOE genes in a sample of the Argentinean population previously studied for 2 polymorphisms in SLC6A4 (Solute Carrier Family 6 Member 4) gene. Five polymorphisms were studied (rs6311 and rs6313 in HTR2A; rs429358 and rs7412 in APOE, and rs6265 in BDNF) in 95 MDD patients and 107 non-related controls. No statistically significant differences were observed between groups when analyzing the association with a single marker using logistic regression; however, when a possible combinatory effect of the polymorphisms (including previously studied polymorphisms in SLC6A4 gene) was analyzed using a dominant model for the risk alleles, the genotypes L/S_10/12_G/A (OR=3.57(95%CI=1.43-8.93); p=0.004, adjusted p-value=0.01) in SLC6A4 and BDNF genes and L/S_10/12_T/C_3/3_G/A in SLC6A4, HTR2A, APOE and BDNF genes (OR=5.99(95%CI=1.66-21.56); p=0.002, adjusted p-value=0.07), were more prevalent in patients than in controls (20%vs.6% and 15%vs.3%, respectively). Even though it is necessary to replicate these findings in a larger population, our results suggest a possible interaction between molecules involved in neurogenesis (BDNF and APOE), serotoninergic neurotransmission (SLC6A4 and HTR2A) and the pathogenesis of MDD. (AU)

La disfunción en la neurotransmisión serotoninérgica ha sido clásicamente asociada con el trastorno depresivo mayor (TDM); sin embargo, otras vías y procesos parecerían tener un rol en esta enfermedad, como la neurogénesis y moléculas asociadas: el factor neurotrófico derivado del cerebro (BDNF) y la apoliproteína E (APOE). Existen reportes en los que se establecen asociaciones entre polimorfismos en estos genes y el TDM. El objetivo de nuestro trabajo fue analizar la posible asociación entre el TDM y polimorfismos en los genes HTR2A (receptor 5-hidroxitriptamina 2A), BDNF y APOE en una muestra de la población argentina previamente estudiada para 2 polimorfismos en el gen SLC6A4 (transportador soluble familia 6 miembro 4). Se estudiaron 5 polimorfismos (rs6311 y rs6313 en HTR2A; rs429358 y rs7412 en APOE; rs6265 en BDNF) en 95 pacientes con TDM y 107 controles no relacionados. No se observaron diferencias significativas entre grupos al analizar la asociación por regresión logística con un único marcador; cuando se analizó el posible efecto combinatorio de polimorfismos (incluyendo los previamente estudiados para el gen SCL6A4) usando un modelo dominante para los alelos de riesgo, los genotipos L/S_10/12_G/A (OR=3,57(95%CI=1,43-8,93); p=0,004, valor-p-ajustado=0,01) en SLC6A4 y BDNF y L/S_10/12_T/C_3/3_G/A en SLC6A4, HTR2A, APOE y BDNF (OR=5,99(95%CI=1,66-21,56); p=0,002, valor-p-ajustado=0,07), fueron más prevalentes en pacientes que controles (20%vs.6% y 15%vs.3% respectivamente). Si bien es necesario replicar estos hallazgos en una población más grande, nuestros resultados sugieren una posible interacción entre moléculas involucradas en la neurogénesis (BDNF y APOE), la neurotransmisión serotoninérgica (SLC6A4 y HTR2A) y la patogenia de la depresión mayor. (AU)

Alanyl-glutamine attenuates 5-fluorouracil-induced intestinal mucositis in apolipoprotein E-deficient mice

Apolipoprotein E (APOE=gene, apoE=protein) is a known factor regulating the inflammatory response that may have regenerative effects during tissue recovery from injury. We investigated whether apoE deficiency reduces the healing effect of alanyl-glutamine (Ala-Gln) treatment, a recognized gut-trophic nutrient, during tissue recovery after 5-FU-induced intestinal mucositis. APOE-knockout (APOE-/-) and wild-type (APOE+/+) C57BL6J male and female mice (N=86) were given either Ala-Gln (100 mM) or phosphate buffered saline (PBS) by gavage 3 days before and 5 days after a 5-fluorouracil (5-FU) challenge (450 mg/kg, via intraperitoneal injection). Mouse body weight was monitored daily. The 5-FU cytotoxic effect was evaluated by leukometry. Intestinal villus height, villus/crypt ratio, and villin expression were monitored to assess recovery of the intestinal absorptive surface area. Crypt length, mitotic, apoptotic, and necrotic crypt indexes, and quantitative real-time PCR for insulin-like growth factor-1 (IGF-1) and B-cell lymphoma 2 (Bcl-2) intestinal mRNA transcripts were used to evaluate intestinal epithelial cell turnover. 5-FU challenge caused significant weight loss and leukopenia (P<0.001) in both mouse strains, which was not improved by Ala-Gln. Villus blunting, crypt hyperplasia, and reduced villus/crypt ratio (P<0.05) were found in all 5-FU-challenged mice but not in PBS controls. Ala-Gln improved villus/crypt ratio, crypt length and mitotic index in all challenged mice, compared with PBS controls. Ala-Gln improved villus height only in APOE-/- mice. Crypt cell apoptosis and necrotic scores were increased in all mice challenged by 5-FU, compared with untreated controls. Those scores were significantly lower in Ala-Gln-treated APOE+/+ mice than in controls. Bcl-2 and IGF-1 mRNA transcripts were reduced only in the APOE-/--challenged mice. Altogether our findings suggest APOE-independent Ala-Gln regenerative effects after 5-FU challenge.

MiR-34a, miR-21 and miR-23a as potential biomarkers for coronary artery disease: a pilot microarray study and confirmation in a 32 patient cohort

The aim of this study was to investigate the expression of circulating microRNAs (miRNAs) in apolipoprotein E (apoE) knockout mice (apoE-/-) and to validate the role of these miRNAs in human coronary artery disease (CAD). Pooled plasma from 10 apoE-/- mice and 10 healthy C57BL/6 (B6) mice was used to perform the microarray analysis. The results showed that miR-34a, miR-21, miR-23a, miR-30a and miR-106b were differentially expressed in apoE-/- mice, and these expression changes were confirmed by real-time quantitative reverse-transcription PCR. Then, miR-34a, miR-21, miR-23a, miR-30a and miR-106b were detected in the plasma of 32 patients with CAD and of 20 healthy controls. Only miR-34a, miR-21 and miR-23a were significantly differentially expressed in the plasma of CAD patients (all P<0.01). In conclusion, miR-34a, miR-21 and miR-23a were elevated in CAD patients, which means that these miRNAs might serve as biomarkers of CAD development and progression.

Differentiated miRNA expression and validation of signaling pathways in apoE gene knockout mice by cross-verification microarray platform

The microRNA (miRNA) regulation mechanisms associated with atherosclerosis are largely undocumented. Specific selection and efficient validation of miRNA regulation pathways involved in atherosclerosis development may be better assessed by contemporary microarray platforms applying cross-verification methodology. A screening platform was established using both miRNA and genomic microarrays. Microarray analysis was then simultaneously performed on pooled atherosclerotic aortic tissues from 10 Apolipoprotein E (apoE) knockout mice (apoE-/-) and 10 healthy C57BL/6 (B6) mice. Differentiated miRNAs were screened and cross-verified against an mRNA screen database to explore integrative mRNA-miRNA regulation. Gene set enrichment analysis was conducted to describe the potential pathways regulated by these mRNA-miRNA interactions. High-throughput data analysis of miRNA and genomic microarrays of knockout and healthy control mice revealed 75 differentially expressed miRNAs in apoE-/- mice at a threshold value of 2. The six miRNAs with the greatest differentiation expression were confirmed by real-time quantitative reverse-transcription PCR (qRT-PCR) in atherosclerotic tissues. Significantly enriched pathways, such as the type 2 diabetes mellitus pathway, were observed by a gene-set enrichment analysis. The enriched molecular pathways were confirmed through qRT-PCR evaluation by observing the presence of suppressor of cytokine signaling 3 (SOCS3) and SOCS3-related miRNAs, miR-30a, miR-30e and miR-19b. Cross-verified high-throughput microarrays are optimally accurate and effective screening methods for miRNA regulation profiles associated with atherosclerosis. The identified SOCS3 pathway is a potentially valuable target for future development of targeted miRNA therapies to control atherosclerosis development and progression.

Apolipoprotein E polymorphism in cerebrovascular & coronary heart diseases.

The role of apolipoprotein E (apo E) in lipid metabolism and cholesterol transport is well established. About 14 per cent of the variation in plasma cholesterol levels is attributed to polymorphisms in apo E gene (APOapo E). E consists of three common alleles, designated as ε2, ε3 and ε4 which code for E2, E3 and E4 proteins respectively resulting in three homozygous (E2/E2, E3/E3, E4/E4) and three heterozygous (E3/E2, E4/E2 and E4/E3) phenotypes. Different populations studied worldwide inherit variable frequencies of the E alleles and genotypes, with the most frequent allele being ε3.The ε4 allele has been consistently shown to be associated with Alzheimer’s disease, coronary heart disease and cerebrovascular disorders. In this review, we have discussed the role of apo E polymorphisms in cerebrovascular and coronary heart diseases. The status of apo E polymorphisms and their disease associations in Asian Indians besides, other populations has also been discussed. Further, studies elucidating the pathophysiology of apo E deficiency conducted in knock-out mice have been reviewed.

Oral rapamycin attenuates atherosclerosis without affecting the arterial responsiveness of resistance vessels in apolipoprotein E-deficient mice

The objective of the present study was to assess the effects of the immunosuppressant rapamycin (Rapamune®, Sirolimus) on both resistance vessel responsiveness and atherosclerosis in apolipoprotein E-deficient 8-week-old male mice fed a normal rodent diet. Norepinephrine (NE)-induced vasoconstriction, acetylcholine (ACh)- and sodium nitroprusside (SNP)-induced vasorelaxation of isolated mesenteric bed, and atherosclerotic lesions were evaluated. After 12 weeks of orally administered rapamycin (5 mg·kg-1·day-1, N = 9) and compared with untreated (control, N = 9) animals, rapamycin treatment did not modify either NE-induced vasoconstriction (maximal response: 114 ± 4 vs 124 ± 10 mmHg, respectively) or ACh- (maximal response: 51 ± 8 vs 53 ± 5 percent, respectively) and SNP-induced vasorelaxation (maximal response: 73 ± 6 vs 74 ± 6 percent, respectively) of the isolated vascular mesenteric bed. Despite increased total cholesterol in treated mice (982 ± 59 vs 722 ± 49 mg/dL, P < 0.01), lipid deposition on the aorta wall vessel was significantly less in rapamycin-treated animals (37 ± 12 vs 68 ± 8 µm² x 10³). These results indicate that orally administered rapamycin is effective in attenuating the progression of atherosclerotic plaque without affecting the responsiveness of resistance vessels, supporting the idea that this immunosuppressant agent might be of potential benefit against atherosclerosis in patients undergoing therapy.

Polimorfismo genético de la apolipoproteína E en un grupo de escolares del centro-oriente colombiano: comparación con las concentraciones plasmáticas de lípidos y apolipoproteínas / Genetic polymorphism of the E apolipoprotein in school age children: comparison with levels of plasma lipids and apolipoproteins

Introducción. Estudios mundiales han demostrado la contribución de los alelos de la apolipoproteína E en las variaciones de los lípidos y las apolipoproteínas. Objetivo. Determinar la frecuencia alélica y genotípica de la apolipoproteína E y su asociación con los lípidos y apolipoproteínas en escolares de la región centro-oriental de Colombia. Materiales y métodos. El tamaño de la muestra fue de 691 escolares entre los 5 y 15 años, de los departamentos de Cundinamarca, Boyacá, Meta, Santander y Norte de Santander. Los genotipos de la apolipoproteína E se identificaron por reacción en cadena de la polimerasa-polimorfismo de longitud del fragmento de restricción. Se analizaron las variables lipídicas de colesterol total, colesterol HDL, colesterol LDL, triglicéridos y colesterol VLDL, apolipoproteína A-I y apolipoproteína B-100. Resultados. Las frecuencias de los alelos e2, e3 y e4 fueron 0,04, 0,86 y 0,08, respectivamente. El grupo E4 (E4/3-E4/4) comparado con el grupo E2 (E3/2-E2/2) presentó las concentraciones plasmáticas más altas de colesterol total, colesterol LDL y apolipoproteína B-100 (p=0,014, 0,001 y 0,000, respectivamente), lo mismo ocurre al comparar el grupo E3/3 con el E2 (p=0,015, 0,002 y 0,002, respectivamente); la influencia del polimorfismo de la apolipoproteína E fue mayor en las niñas. Conclusiones. La asociación del alelo e4 con niveles más altos de colesterol total, colesterol LDL y apolipoproteína B-100 muestra la importancia de realizar otros estudios sobre el polimorfismo de la apolipoproteína E, su interacción con otros genes, estilos de vida y factores de riesgo y su posible contribución para el desarrollo de enfermedad cardiovascular.

Introduction. Research in laboratories around the world has documented the contribution of the E apolipoprotein alleles to structural variations of lipids and apolipoproteins. Objective. The gene frequencies of the E apolipoprotein alleles were compared with the lipid and apolipoprotein levels in school age children. Materials and methods. Six hundred and ninety one 5 to 15 years old school age children from the Colombian departments of Cundinamarca, Boyacá, Meta, Santander and Norte de Santander, were evaluated.The genotypes of the E apolipoprotein were identified by polymerase chain reaction-restriction fragment length polymorphism. Plasma levels for the following 5 lipids and lipoproteins were assayed: total cholesterol, HDL (high density lipoprotein) cholesterol, LDL (low density lipoprotein) cholesterol, triglycerides, VLDL (very low density lipoprotein) cholesterol, A-I apolipoprotein and B-100 apolipoprotein. Results. Alleles e2, e3 and e4 were found in frequencies of 0.04, 0.86 and 0.08, respectively. The E4 group (E4/3-E4/4), in contrast with the E2 group (E3/2-E2/2), presented highest plasma concentrations of total cholesterol, LDL cholesterol and B-100 apolipoprotein (p=0.014, 0.001 and 0.000, respectively). When the E3/3 group was compared with E2, the same result was obtained (p=0.015, 0.002 and 0.002, respectively). The influence of the E apolipoprotein polymorphism appeared greater in female children than male. Conclusions. The e4 allele was associated with higher levels of total cholesterol, LDL cholesterol and B-100 apolipoprotein and indicates the necessity of additional research into the interactions between polymorphism E apolipoprotein and other genes, life styles, risk factors and potential contribution to cardiovascular diseases.

Efecto de la infección periodontal por porphyromonas gingivalis en el desarrollo de ateroesclerosis en ratones deficientes de apolipoproteína E / Effects of porphyromona gingivalis periodontal infection upon atherosclerosis development in apolipoprotein-E

Introducción: Nuestro grupo recientemente demostró una asociación significativa entre periodontitis, placas coronarias aguda y extensión de la enfermedad coronaria aterosclerótica en pacientes con síndrome coronario agudo. Objetivo: Desarrollar un modelo experimental animal para estudiar el posible efecto pro-aterogénico de la inducción de periodontitis por Porphyromona Gingivalis (PG) en ratones deficientes en la apolipoproteína E (APO-E KO). Métodos: En 12 ratones APO-E KO mantenidos con dieta hiperlipidémica se realizaron tocaciones con PG cepa ATCC 53977 en el surco gingival de los molares mandibulares a las 8 semanas de vida. Igual número de ratones APO-E KO fue intervenido con el mismo procedimiento, pero sólo con el vehículo de las tocaciones. Estos procedimientos se repitieron a las 48, 72 y 120 hrs de la infección inicial. Luego de 4 semanas post-inoculación con PG se realizaron estudios histomorfométricos en la aorta proximal para medir la severidad de las lesiones ateromatosas y en las mandíbulas, para evaluar la pérdida del hueso alveolar. Resultados: No se observó una diferencia significativa en el daño del hueso alveolar en las mandíbulas de los animales infectados versus el grupo control. En las aortas, la razón tamaño placa/pared vascular fue mayor en el grupo infectado con PG que en el grupo control (0.132 ± 0.2 versus 0.103 ± 0.15, respectivamente), pero esta diferencia no fue estadísticamente significativa. Conclusión: El diseño experimental del presente estudio no permitió establecer si la periodontitis inducida por PG es capaz o no de acelerar el proceso aterogénico de los ratones APO-E KO. Será necesario aplicar un protocolo de infección periodontal más agresivo en estos animales para evaluar más adecuadamente el efecto de PG sobre la ateroesclerosis.

Absence of the E2 allele of apolipoprotein in Amerindians

A determinaçäo da distribuiçäo do alelo ApoE em cinco tribos de índios sulamericanos revelou ausência do alelo ApoE2, acompanhada por freqüência alta do alelo ApoE3 e baixa do alelo ApoE4 na maioria das tribos, uma distribuiçäo previamente relatada apenas para os esquimós Inuit da Groenlândia.