Increased kynurenine concentration attenuates serotonergic neurotoxicity induced by 3,4-methylenedioxymethamphetamine (MDMA) in rats through activation of aryl hydrocarbon receptor.

3,4-Methylenedioxymethamphetamine (MDMA) is an amphetamine derivative that has been shown to produce serotonergic damage in the brains of primates, including humans, and of rats. Tryptophan, the precursor of serotonin, is primarily degraded through the kynurenine (KYN) pathway, producing among others KYN, the main metabolite of this route. KYN has been reported as an endogenous agonist of the aryl hydrocarbon receptor (AhR), a transcription factor involved in several neurological functions. This study aims to determine the effect of MDMA on the KYN pathway and on AhR activity and to establish their role in the long-term serotonergic neurotoxicity induced by the drug in rats. Our results show that MDMA induces the activation of the KYN pathway, mediated by hepatic tryptophan 2,3-dioxygenase (TDO). MDMA also activated AhR as evidenced by increased AhR nuclear translocation and CYP1B1 mRNA expression. Autoradiographic quantification of serotonin transporters showed that both the TDO inhibitor 680C91 and the AhR antagonist CH-223191 potentiated the neurotoxicity induced by MDMA, while administration of exogenous l-kynurenine or of the AhR positive modulator 3,3'-diindolylmethane (DIM) partially prevented the serotonergic damage induced by the drug. The results demonstrate for the first time that MDMA increases KYN levels and AhR activity, and these changes appear to play a role in limiting the neurotoxicity induced by the drug. This work provides a better understanding of the physiological mechanisms that attenuate the brain damage induced by MDMA and identify modulation of the KYN pathway and of AhR as potential therapeutic strategies to limit the negative effects of MDMA.

Implicación de la molécula de adhesión ALCAM en el daño cerebral. Modelo de daño neuronal mediante la administración de MDMA/éxtasis en rata / Implication of the adhesion molecule ALCAM in the experimental rat model of brain damage caused by MDMA/ecstasy

Objetivo: Caracterizar la expresión de ALCAM en vasos de corteza cerebral de ratas tratadas con MDMA. 2) Estudiar el efecto que sobre su expresión y sobre la neurotoxicidad producida por MDMA tiene ibuprofeno. Materiales y métodos: Se administró una dosis neurotóxica de MDMA a ratas Dark Agouti e buprofeno a diferentes tiempos. Se midió la temperatura de los animales durante los tratamientos y se estudió la expresión de ALCAM en los vasos de corteza. El daño cerebral se estudió midiendo los niveles de ácido 5-indolacético, serotonina y la densidad de su transportador. Resultados: MDMA produce un aumento de ALCAM a las 24 horas (p<0.01). El co-tratamiento con ibuprofeno lo disminuye (p<0.01) y atenúa el daño cerebral disminuyendo los efectos neurotóxicos de MDMA sobre los niveles de serotonina cortical (p<0.0001) y la densidad del transportador (p<0.0001). Ibuprofeno disminuye ligeramente la hipertermia producida por MDMA. Conclusiones: MDMA aumenta la expresión de ALCAM. Los datos sugieren la posibilidad de utilizar compuestos anti-inflamatorios como ibuprofeno que reducen este efecto sobre ALCAM y que disminuyen parcialmente el daño cerebral, si bien es necesario analizar la participación de la disminución de la temperatura en dicha protección (AU)

Objective: 1) Characterization of ALCAM adhesion molecule expression in cortical vessels of MDMA-treated rats. 2) Study of the effect of the anti-inflammatory compound ibuprofen on ALCAM expression and on the neurotoxicity produced by MDMA. Material and methods: Male Dark Agouti rats were given a neurotoxic dose of MDMA. Ibuprofen was given before and at various times after MDMA. Rectal temperature was monitored during the treatment and ALCAM expression in vessels from cerebral cortex was determined at 24 h. In neurotoxicity studies, cortical 5-HT tissue levels and 5-HT transporter density were measured. Results: ALCAM expression was increased 24 h after MDMA treatment (p<0.01). Co-treatment with ibuprofen attenuated the increase in ALCAM levels (p<0.01) and partially prevented cerebral injury, reducing MDMA-induced 5-HT (p<0.0001) and 5-HT transporter (p<0.0001) loss. Ibuprofen produced a minor modification in the MDMA-induced hyperthermia. Conclusions: Our study demonstrates an effect of MDMA on ALCAM expression. Thus, anti-inflammatory compounds such as ibuprofen may result useful in brain protection by inhibiting the effects of ALCAM and reducing brain damage although the potential contribution of the attenuation of MDMA-induced hyperthermia must also be considered (AU)

Involvement of 2-arachidonoyl glycerol in the increased consumption of and preference for ethanol of mice treated with neurotoxic doses of methamphetamine.

BACKGROUND AND PURPOSE: Methamphetamine (METH) is a psychostimulant amphetamine that causes long-term dopaminergic neurotoxicity in mice. Hypodopaminergic states have been demonstrated to increase voluntary ethanol (EtOH) consumption and preference. In addition, the endocannabinoid system has been demonstrated to modulate EtOH drinking behaviour. Thus, we investigated EtOH consumption in METH-lesioned animals and the role of cannabinoid (CB) signalling in this EtOH drinking. EXPERIMENTAL APPROACH: Mice were treated with a neurotoxic regimen of METH, and 7 days later exposed to increasing concentrations of drinking solutions of EtOH (3, 6, 10 and 20%). Seven days after neurotoxic METH, the following biochemical determinations were carried out in limbic forebrain: CB(1) receptor density and stimulated activity, 2-arachidonoyl glycerol (2-AG) and monoacylglycerol lipase (MAGL) activity, dopamine levels and dopamine transporter density. KEY RESULTS: EtOH consumption and preference were increased in METH-treated mice. Seven days after METH, a time at which both dopamine levels and density of dopamine transporters in limbic forebrain were decreased, CB(1) receptor density and activity were unaltered, but 2-AG levels were increased. At this same time-point, MAGL activity was reduced. The CB(1) receptor antagonist AM251 prevented the METH-induced increase in EtOH consumption and preference, while N-arachidonoyl maleimide, an inhibitor of MAGL, increased EtOH consumption and preference in both saline- and METH-treated mice. CONCLUSIONS AND IMPLICATIONS: An increase in endocannabinoid tone may be involved in the increased consumption of and preference for EtOH displayed by METH-lesioned mice as blockade of the CB(1) receptor decreased EtOH-seeking behaviours, whereas the MAGL inhibitor increased EtOH consumption.

Implication of the tetraspanin CD9 in the immune system and cancer

Las tetraspaninas son moléculas de la superficie celular de ampliadistribución en los organismos eucarióticos. Poseen como característicaestructural peculiar cuatro dominios transmembranales, regionesN- y C-terminales intracitoplásmicas, y dos lazos extracelularesde distinto tamaño. También poseen un motivo de secuencia CCGen el lazo extracelular mayor, así como residuos polares conservadosen los dominios transmembranales. Las células sanguíneas delos mamíferos expresan combinaciones peculiares de distintas tetraspaninas,incluyendo los antígenos de diferenciación CD9, CD37,CD53, CD81/TAPA-1, CD82, CD151/PETA-3 y CD231/TALLA1.En este trabajo se resumen la estructura y las interacciones desus regiones citoplásmicas con proteínas del citoesqueleto y señalizadoras,como la proteína cinasa C (PKC) o la Fosfatidil-Inositol 4-cinasa (PI4-K). Sus interacciones específicas con otras tetraspaninas,con integrinas, antígenos de histocompatibilidad, y miembros dela superfamilia de las inmunoglobulinas son también revisadas.Las tetraspaninas son proteínas “adaptadoras” o “facilitadoras”.Al formar parte de complejos moleculares, modulan funcionescelulares clave que incluyen la fusión celular, la adhesión, lamigración, la diferenciación y la transducción de señales. Las tetraspaninasse organizan en una red con distintos niveles de asociación,determinados por su resistencia a la solubilización por detergentes.En concreto, se analizan las tetraspaninas como reguladorasdel Sistema Inmunitario gracias a sus interacciones con los receptoresde antígeno de los linfocitos T y B, las moléculas de histocompatibilidadde clase I y clase II, y los co-receptores CD2, CD4,CD5, CD8 y CD19. Por último, se revisa detalladamente el papelde la tetraspanina CD9 en la función de las células linfoides y mieloides,su relevancia en infecciones como el HIV, y la importanciade su asociación con integrinas en la progresión cancerosa

Tetraspanins are cell surface proteins widely distributed ineukaryotic organisms. They characteristically span four times theplasma membrane, have intracellular N and C terminal regions,and two extracellular loops of unequal size. Tetraspanins also possessa CCG motif in the large extracellular loop, and conservedpolar residues in the transmembrane domains. Mammalian bloodcells express different sets of tetraspanins including the differentiationantigens CD9, CD37, CD53, CD81/TAPA-1, CD82,CD151/PETA-3 and CD231/TALLA1.Here, tetraspanin structure and their cytoplasmic tail interactionswith cytoskeletal and signalling proteins like Protein kinaseC (PKC) or Phosphatidyl Inositol 4-kinase (PI4-K) are brieflysummarized. The specific interactions with other cell surface proteins,forming complexes with other tetraspanins and membersof the integrin family, MHC histocompatibility antigens, or membersof the immunoglobulin superfamily are also reviewed.Tetraspanins are considered as “adapter” or “facilitating” proteinsand, through their participation in complexes, they modulatekey cellular functions like cell fusion, adhesion, migration,differentiation and signal transduction. The organization of thetetraspanin web, based on different association levels determinedby their resistance to detergent solubilization, is described. In particular,tetraspanins participating in the regulation of the ImmuneSystem through interactions with the B- and T-cell receptors,the class I and class II MHC antigens, and co-receptors such asCD2, CD4, CD5, CD8, or CD19 are analyzed. At last, the role ofCD9 in myeloid and lymphoid cell function, its relevance to HIVinfection, and the importance of tetraspanin association with integrinsto cancer progression are described in detail

Phosphodiesterases 4D and 7A splice variants in the response of HUVEC cells to TNF-alpha(1).

The mRNA accumulation of phosphodiesterases PDE4D and PDE7A was studied by RNA blot analysis in human umbilical vein endothelial cells (HUVEC) incubated with TNFalpha for different periods. A contrasting behaviour was observed in the mRNA accumulation of the two genes. Further analysis by RT-PCR of the PDE4D and PDE7A splice variants gave different accumulation patterns which may indicate that differential splicing has a role in the regulation of these enzymes. Three previously undescribed PDE4D isoforms, with different accumulation patterns, were also detected. They code for truncated PDE4D isoforms, which could participate in the regulation of PDE4D activity.

HLA-DR, DQ and anti-GAD antibodies in first degree relatives of type I diabetes mellitus.

The differential antibody response to glutamic acid decarboxylase (anti-GAD) and to islet cell cytoplasm (ICA) according to HLA-DR and DQ genotypes were examined in 28 Spanish patients with Type I diabetes mellitus (11.1 +/- 10.4 year diabetes duration) and their 41 first degree non-diabetic relatives. Anti-GAD was detected by radioimmunoprecipitation and ICA by indirect immunofluorescence and HLA-DR/DQ alleles were assigned by PCR and sequence specific oligonucleotide probes. The frequency in patients of positivity for ICA was 7.1% and of anti-GAD+ 64.3%, and in relatives, the frequency of ICA+ was 4.9%, and anti-GAD+ 9.8%. Concurrent positivity for ICA and anti-GAD existed in only one patient, and in none of the relatives. We confirm for a Spanish population the high frequency of risk genotypes for Type I, involving DR3, DR4 and DQB1*0302 (DQ8) which were present in 26 of 28 (93%) patients and 32 of 41 (78%) relatives. The most frequent genotypes were DR3/DQB1*0201/DQA1*0501-DR4/DQB1*0302/DQA1*0301( 9 patients, 32%; 6 relatives, 15%), DR3/DQB1*0201/ DQA1*0501-DR3/DQB1*0201/DQA1*0501 (5 patients, 18%; 7 relatives, 17%) and DE3/DQB1*0201/DQA1*0501-DR1/ DQB1*0501/DQA1*0101(5 patients, 18%; 1 relative, 2%). Positivity for anti-GAD or for ICA did not correlate with gender, or age at onset or duration of DM. The distribution of high risk HLA genotypes were similar regardless the anti-GAD or anti-ICA status either in patients or in their relatives.

Genetic predisposition and environmental factors leading to the development of insulin-dependent diabetes mellitus in Chilean children.

This study was designed to examine the hypothesis that some environmental factors increase the risk for insulin-dependent diabetes mellitus. Data on dietary history was collected from 80 diabetic children from the Santiago de Chile Registry and from 85 nondiabetic control subjects who were comparable in terms of age, sex, and ethnic characteristics. Early exposure was defined as the ingestion of food sources other than maternal milk before 3 months of age. To define genetic susceptibility to insulin-dependent diabetes mellitus each subject was typed in terms of HLA DQA1 and DQB1, and the possible conformation of susceptible heterodimers was considered as a risk marker. Fewer children were exclusively breast fed in the diabetic group than in the control group (21.55 +/- 15.05 vs 33.95 +/- 20.40 weeks, P<0.01). In addition, exposure to cow's milk and solid foods occurred earlier in the diabetic group than in the control group (15.90 +/- 10.95 vs 21.15 13.65 and 16.85 +/- 10.25 vs 21.20 +/- 12.35 weeks, P<0.05). Our data show that a short duration of breast-feeding and early exposure to cow's milk and solid foods may be important factors in the development of insulin-dependent diabetes mellitus. The high relative risk observed in individuals genetically predisposed indicates an interaction effect between genetic and environmental components.

[HLA and insulin-dependent diabetes mellitus]. / HLA y diabetes mellitus insulinodependiente.

The propensity of an individual to develop type I (insulin dependent) diabetes mellitus is directly related to specific HLA class II proteins, specially those from DR and DQ regions. Genetic susceptibility to insulin dependent diabetes arises from a preestablished conformation of alpha and beta chains of DQ and beta chain of DR. Since the classic demonstration by McDevitt and colleagues that DQ beta chain aspartate at position 57 was protective against the development of the disease, many populations have been surveyed to study the association between the incidence Type I diabetes and determined frequencies of DR and DQ haplotypes. The association between these markers and susceptibility to Type I diabetes is well established in caucasians at the present time. However, little information is available for Latin American populations, that share a mixture of european, african and native genes. Our group is studying genetic markers of three Latin American populations (Argentina, Perú and Chile) and their possible association to the different incidence of Type I diabetes mellitus in each country.

Lipoprotein (a) and other risk factors in children with insulin-dependent diabetes mellitus and children without diabetes.

AIMS: To study serum Lp(a) levels and other metabolic cardiovascular risk factors in children with Type 1 diabetes mellitus (DM) compared to sex and age matched nondiabetic children. The correlation of Lp(a) serum levels and other lipid parameters with HbA1c concentrations in diabetic children was investigated. DESIGN: Transversal observational study. TARGET POPULATION: 36 C-peptide negative Type 1 DM children without microalbuminuria and no macromicrovascular or neurological complications, aged 8 to 15 years; 17 boys, 19 girls. Mean duration of Type 1 DM was 4.99 +/- 3.04 years, daily insulin need were 32.79 +/- 12.64 Units. 41 healthy children with no family history of DM, aged from 8 to 15 years, 26 boys, 15 girls, were studied in parallel as the control group. METHODS: Serum total cholesterol (TC) and triglycerides (TG) were assayed by enzymatic methods, high-density lipoprotein (HDL) cholesterol by enzymatic method after precipitation of very-low-density (VLDL) and low-density lipoprotein (LDL) fractions. The LDL fractions was estimated after serum precipitation as the difference between total cholesterol and supernatant cholesterol concentrations. Apo-AI, apo-AII and apo-B were measured by radial immunodiffusion assays. Serum Lp(a) was measured by monoclonal anti-Lp(a) antibody (ELISA) method and whole blood glycosylated hemoglobin A1c (HbA1c) by high resolution liquid chromatography. RESULTS: HbA1c concentration in diabetic children was 7.51 +/- 54% vs 4.16 +/- 0.35% in non diabetic children. Lp(a) serum levels did not significantly differ among both groups (25 +/- 22 mg/dl in diabetics subjects, 22 +/- 22 mg/dl in controls). Significant correlation was found between HbA1c levels and each of TC, LDL and TG serum concentrations in the diabetic group. Lp(a) levels were correlated with glycated hemoglobin in the whole diabetic group. But, in the 2 patients with the poorest metabolic control (HbA1c 10.5%) were excluded, the correlation disappeared. CONCLUSIONS: In 36 children aged 5-15 years with uncomplicated Type 1 DM lasting less than 15 years, Lp(a) serum levels did not differ from age-matched controls but highest Lp(a) values were associated with poorest metabolic control.

[Lipoprotein (a) and other risk factors in Chilean children with type I diabetes mellitus]. / Lipoproteina (a) y otros factores de riesgo en niños chilenos con Diabetes Mellitus Tipo I.

AIMS: To study serum Lp(a) levels and other metabolic cardiovascular risk factors in children with type I diabetes mellitus (DM) in comparison with sex and age matched nondiabetic children. To determine the influence of diabetes control on serum lipoprotein (a) concentrations. DESIGN: Transversal observational study. TARGET POPULATION: diabetic group: 70 type I DM children without microalbuminuria and no macro-microvascular nor neurological complications, aged from 8 to 15 years; 30 boys, 40 girls. Mean duration of type I DM was 8 +/- 4 years. Non diabetic group: composed by 123 healthy children with no family history of DM, aged from 8 to 15 years, 53 boys, 70 girls. METHODS: The lipids profile include: total cholesterol (TC) and triglyceride (TG), cholesterol high-density lipoproteins (C-HDL) cholesterol very-low-density lipoproteins (C-LDL) and cholesterol low-density lipoproteins (C-LDL). ApoAI, APOAII and ApoB, Lp(a) and fructosamine. RESULTS: Fructosamine concentration in diabetic children was 340 +/- 108 uM/1 in 240 +/- 25 uM/l nondiabetic children. Lp(a) serum levels did not significantly differ among both groups 17 +/- 16 mg/dl in diabetics 19 +/- 18 mg/dl in controls. Multivariate analysis showed that in the diabetic children the worsening of metabolic control as reflected by fructosamine, was positively correlated with the increase in total Lp(a) serum concentration. CONCLUSIONS: In children aged 8-15 years with uncomplicated IDDM lasting less than 15 years duration, Lp(a) serum levels are positively correlated with the poorest metabolic control.

[Lipoprotein (a), atherosclerosis, and diabetes mellitus]. / Lipoproteina (a), aterosclerosis y diabetes mellitus.

Diabetes mellitus is associated with a three to fourfold increased risk for coronary artery disease and diabetic patients frequently have an abnormal plasma lipid profile. Lately, lipoprotein (a) has received attention as an important independent risk factor for cardiovascular disease. This lipoprotein is elevated in patients with type II diabetes mellitus and there may be an association between the metabolic control of these subjects and its levels. In this review the main features of lipoprotein (a) and its relationship to the fibrinolytic system and atherosclerosis are reviewed.

Lipoprotein (a) and other risk factors in children with insulin-dependent diabetes mellitus and children without diabetes.

AIMS: To study serum Lp (a) levels and other metabolic cardiovascular risk factors in children with type 1 diabetes mellitus (DM) as compared to sex and age matched nondiabetic children. The correlation of Lp (a) serum levels and other lipid parameters with HbA1c concentration in diabetic children was investigated. DESIGN: Transversal observational study. TARGET POPULATION: 36 C-peptide negative Type 1 diabetic children without microalbuminuria and no macromicrovascular nor neurological complications, aged 8 to 15 years; 17 boys, 19 girls. Mean duration of Type 1 diabetes was 4.99 +/- 3.04 years, daily insulin needs 32.79 +/- 12.64 Units. 41 healthy children with no family history of diabetes mellitus, aged 8 to 15 years, 26 boys, 15 girls, were studied in parallel as the control group. METHODS: Serum total cholesterol and triglycerides were assayed by enzymatic methods, High-density lipoprotein (HDL) cholesterol by enzymatic method after precipitation of very-low-density (VLDL) and low-density lipoprotein (LDL) fractions. The LDL fraction was estimated after serum precipitation as the difference between total cholesterol and supernatant cholesterol concentrations. Apo-AI, apoA-II and apo-B were measured by radial immunodiffusion assays. Serum Lp(a) was measured by a monoclonal anti-Lp(a) antibody (ELISA) method and whole blood glycosylated hemoglobin A1c (HbA1c) by high resolution liquid chromatography. RESULTS: HbA1c concentration in diabetic children was 7.51 +/- 1.54% vs 4.16 +/- 0.35% in nondiabetic children. Lp(a) serum levels did not significantly differ among both groups (25 +/- 22 mg/dl in diabetics; 22 +/- 22 mg/dl in controls). Significant correlation was found between HbA1c levels and each of TC, LDL and TG serum concentrations in the diabetic group. Lp (a) levels were only correlated with glycated hemoglobin in the two patients showing the highest levels of HbA1c; in the diabetic group: HbA1c 10.9 and 11.5%. CONCLUSIONS: In 36 children aged 8-15 years with uncomplicated Type 1 diabetes for less than 15 years duration, Lp (a) serum levels were positively correlated with HbA1c only in two of them showing the poorest metabolic control.

Susceptibility to type 1 (insulin-dependent) diabetes mellitus in Spanish patients correlates quantitatively with expression of HLA-DQ alpha Arg 52 and HLA-DQ beta non-Asp 57 alleles.

HLA-DQ alpha and beta alleles were chosen as the most sensitive Type 1 (insulin-dependent) diabetes mellitus susceptibility markers for evaluating the disease associations and Type 1 diabetes risk in a population-based registry from Madrid. The absence of aspartic acid in position 57 of the DQ beta chain (non-Asp 57), and the presence of arginine in position 52 of the DQ alpha chain (Arg 52) were found to be reliable markers of Type 1 diabetes susceptibility among the Spanish population, with significantly higher frequencies among the cases of Type 1 diabetes compared to randomly selected non-diabetic control subjects from the general Madrid population. While non-Asp 57 homozygosity conferred an absolute risk of 32.3 per 100,000 per year and Arg 52 of 31.5 per 100,000 per year, the risk for double homozygotes for both non-Asp 57 and Arg 52 was estimated as 101.7 per 100,000 per year. Individuals homozygous for only one of these alleles, and heterozygous at the other locus, had a markedly lower Type 1 diabetes risk (12.8 per 100,000 per year), approximating the general population incidence for Madrid. Thus, susceptibility to Type 1 diabetes in Spanish patients is associated, quantitatively, with non-Asp 57 DQ beta and Arg 52 DQ alpha alleles.