The role of single nucleotide variant rs3819817 of the Histidine Ammonia-Lyase gene and 25-Hydroxyvitamin D on bone mineral density, adiposity markers, and skin pigmentation, in Mexican population.

PURPOSE: Vitamin D (VD) deficiency and osteoporosis have become a global public health problem. A variant in the Histidine Ammonia-Lyase (HAL) gene has been associated with VD levels and bone mineral density (BMD). However, whether this variant has an influence on VD levels and BMD in Mexican adults remain unclear. METHODS: This cross-sectional analysis included 1,905 adults participating in the Health Worker Cohort Study and 164 indigenous postmenopausal women from the Metabolic Analysis in an Indigenous Sample (MAIS) cohort. The rs3819817 variant was genotyped by TaqMan probe assay. Total 25 hydroxyvitamin D levels were measured by DiaSorin Liaison. BMD at the different sites was assessed through dual-energy X-ray absorptiometry. Linear and logistic regression models were performed to evaluate the associations of interest. RESULTS: The prevalence of VD deficiency was 41%, showing differences between sexes. Obesity and skin pigmentation were associated with lower levels of VD in males and females. rs3819817-T allele was associated with low levels of 25-hydroxyvitamin D, VD deficiency, and hip and femoral neck BMD values (g/cm2). We found two interactions with VD levels, one between adiposity and rs3819817-T allele (P = 0.017) and another between skin pigmentation and rs3819817-T allele (P = 0.019). In indigenous postmenopausal women, we observed higher VD levels in the southern region compared to the northern region (P < 0.001); however, we did not observe differences by genotype. CONCLUSION: Our findings confirm that the genetic variant rs3819817 has an essential function in VD levels and BMD and suggests a role in skin pigmentation in the Mexican population.

Crystal structure of histidine ammonia-lyase from Trypanosoma cruzi.

Chagas disease is one of seventeen neglected tropical diseases according to the World Health Organization (WHO). The histidine-glutamate metabolic pathway is an oxidative route that has shown to be relevant for the bioenergetics in Trypanosoma cruzi, the etiological agent for Chagas disease. Histidine ammonia-lyase participates in the first stage of the histidine catabolism, catalyzing the conversion of l-histidine into urocanate. This work presents the three-dimensional (3D) structure of Trypanosoma cruzi histidine ammonia-lyase enzyme (TcHAL) and some comparisons of it to homologous structures. The enzyme was expressed, purified and assayed for crystallization, what allowed the obtainment of crystals of sufficient quality to collect X-ray diffraction data up to 2.55 Å resolution. After refinement, some structural analyses indicated that the structure does not contain the active site protection domain, in opposition to previously known 3D structures from plants and fungi phenylalanine ammonia-lyase, therefore, it is the first structure of eukaryotic ammonia-lyases that lacks this domain.

Hepatic amino acid-degrading enzyme expression is downregulated by natural and synthetic ligands of PPARα in rats.

Body nitrogen retention is dependent on the amount of dietary protein consumed, as well as the fat and carbohydrate content in the diet, due to the modulation of amino acid oxidation. PPARα is a transcription factor involved in the upregulation of the expression of enzymes of fatty acid oxidation. However, the role of putative PPARα response elements (PPREs) in the promoter of several amino acid-degrading enzymes (AADEs) is not known. The aim of this work was to study the effect of the synthetic ligand Wy 14643 and the natural ligands palmitate, oleate, and linoleate in rats fed graded concentrations of dietary protein (6, 20, or 50 g/100 g of total diet) on the expression of the AADEs histidase, serine dehydratase, and tyrosine aminotransferase. Thus, we fed male Wistar rats diets containing 6, 20, or 50% casein for 10 d. The results showed that addition of Wy 14643 to the diet significantly reduced the expression of the AADEs. Furthermore, the incubation of hepatocytes with natural ligands of PPARα or feeding rats with diets containing soybean oil, safflower oil, lard, or coconut oil as sources of dietary fat significantly repressed the expression of the AADEs. Gene reporter assays and mobility shift assays demonstrated that the PPRE located at -482 bp of the histidase gene actively bound PPARα in rat hepatocytes. These data indicate that PPARα ligands may reduce amino acid catabolism in rats.

Histidinemia atípica y desarrollo cognitivo / Atypical hystidinemia and the cognitive development

Introducción: la histidinemia es un defecto metabólico dentro del grupo de aminoacidemias. El defecto enzimático de la histidasa (histidin-amono-liasa) provoca alta concentración de histidina en sangre, líquido cefalorraquídeo, en la orina y en el sudor. Métodos: un estudio de caso muestra el desarrollo evolutivo de un niño con histidinemia atípica y el impacto de la rehabilitación desde la edad temprana hasta la edad escolar. Resultados: la condición patológica causada por la histidinemia atípica limita el desarrollo motor, neurológico, neuropsicológico, conductual y escolar del niño. La rehabilitación temprana muestra que las habilidades primarias de la marcha se adquieren en la etapa esperada, pero los problemas motores complejos mantienen su limitación en el desarrollo. Las dificultades en el lenguaje oral persisten en toda la edad temprana, la rehabilitación posibilita su perfeccionamiento con la edad. Conclusiones: la histidinemia atípica muestra en el desarrollo alteraciones neurológicas, neuropsicológicas, neurofisiológicas, conductuales y académicas. La rehabilitación temprana brinda mejores condiciones de vida del infante. El carácter crónico de la enfermedad posibilita un pronóstico negativo en áreas esenciales como la conducta y la vida escolar(AU)

Introduction: histidinemia is a metabolic defect within the group of aminoacidemias. The enzymatic defect of histidase (histidin-amono-lyase) cause high histidine concentration in the blood, the cerebrospinal fluid, in urine, and sweat. Methods: a case study showed the developmental evolution of a child with atypical histidinemia and the impact of rehabilitation from early age to school age. Results: the pathological condition caused by atypical histidinemia limits the motor, neurological, neuropsychological, behavioural and educational development of the child. The early rehabilitation shows that primary gait abilities are acquired in the expected phase, but the complex motor problems remained in the development phase. The language difficulties persist throughout the early childhood, but rehabilitation makes it possible to improve oral expression as age increases. Conclusions: atypical histidinemia reveals neurological, neuropsychological, neurophysiological, behavioural and academic alterations in the development of the child. The early rehabilitation provides better living conditions to the child. The chronic nature of the disease indicates a negative prognosis in essential areas such as behaviour and education(AU)

Cálculo del intervalo de referencia de la histidina en sangre seca neonatal por suma / Calculation of the histidine reference interval in neonatal dry blood by SUMA

La Histidinemia es una enfermedad metabólica hereditaria rara, caracterizada por una deficiencia de la enzima histidasa, que ocasiona un aumento de las concentraciones de Histidina en sangre, orina y en líquido cefalorraquídeo y en ocasiones hiperalaninemia. Su cuadro clínico varía desde la presencia de retraso mental y un defecto del habla hasta la ausencia de manifestaciones. El diagnóstico de la enfermedad requiere de la aplicación de pruebas basadas en la cuantificación de L-Histidina en sangre. Se determinaron los niveles de Histidina en sangre seca neonatal a 348 muestras, con el propósito de establecer el intervalo de referencia en el laboratorio de este aminoácido. La cuantificación de las muestras se realizó empleando un método ultramicroanalítico, previamente validado en nuestro laboratorio para la cuantificación de Histidina en sangre. El intervalo de referencia en el laboratorio de histidina en sangre seca neonatal, para un 95 por ciento de probabilidad, fue de 4,59-16,74 mg/dL (296-1079 µM)(AU)

Histidinemia is a rare inherited metabolic disorder characterized by deficient histidase enzyme, which results in elevated histidine levels in blood, urine and cerebrospinal fluid and, sometimes, hyperalaninemia. Histidinemia clinical picture varies from mental retardation and speech disorders to absence of any symptoms. This disease can be diagnosed by histidine-level-in-blood-quantitating tests. In the following work the levels of Histidina were determined in neonatal dry blood to 348 samples in order to establish the reference intervals in the laboratory of this amino acid. The quantification of the samples was carried out using an ultra micro analytic method, previously validated in our laboratory for the quantification of Histidina in blood. The obtained reference interval (95 percent probability) in the laboratory was of 4, 59 -16, 74 mg/dL (296-1079 µM)(AU)

Production of recombinant rat hepatic histidase.

Rat liver histidase was expressed in E. coli by using a PCR product of the coding sequence obtained from the rat liver cDNA of histidase cloned in the expression vector pRSET. The construct (pRSET-HAL) produced a fusion protein containing a tail of polyhistidine. The expression product was purified with a resin containing Ni+ that retains proteins with polyhistidine fragments. pRSET-HAL was analyzed by restriction enzyme mapping and by sequencing confirming the correct orientation and nucleotide sequence. Native rat liver histidase was also purified and it had a Mr of 72 kDa. An antiserum against native histidase was obtained in rabbit. Western blot analysis revealed one band of 72 kDa observed in membranes containing purified histidase or rat liver high speed supernatants. The same antiserum also detected in cell lysates of E. coli transformed with the pRSET-HAL plasmid a single band of 74 kDa of the recombinant histidase before cleavage with enterokinase. After the proteolysis, the Western blot analysis showed a single band of approximately 72 kDa. Kinetic analysis of the recombinant histidase showed similar Km and Vmax compared with native histidase.

Production of recombinant rat hepatic histidase / Producción de histidasa recombinante de hígado de rata

Rat liver histidase was expressed in E. coli by using a PCR product of the coding sequence obtained from the rat liver cDNA of histidase cloned in the expression vector pRSET. The construct (pRSET-HAL) produced a fusion protein containing a tail of polyhistidine. The expression product was purified with a resin containing Ni+ that retains proteins with polyhistidine fragments. pRSET-HAL was analyzed by restriction enzyme mapping and by sequencing confirming the correct orientation and nucleotide sequence. Native rat liver histidase was also purified and it had a Mr of 72 kDa. An antiserum against native histidase was obtained in rabbit. Western blot analysis revealed one band of 72 kDa observed in membranes containing purified histidase or rat liver high speed supernatants. The same antiserum also detected in cell lysates of E. coli transformed with the pRSET-HAL plasmid a single band of 74 kDa of the recombinant histidase before cleavage with enterokinase. After the proteolysis, the Western blot analysis showed a single band of approximately 72 kDa. Kinetic analysis of the recombinant histidase showed similar Km and Vmax compared with native histidase.

La histidasa de hígado de rata se expresó a partir del producto de amplificación por PCR de la región codificante del DNAc de la histidasa, el cual se clonó en el vector de expresión pRSET. La construcción (pRSET-HAL) permitió la producción de una proteína de fusión que contenía una cola de polihistidinas. El producto de expresión se purificó con una resina que contiene Ni+, la cual retiene proteínas con fragmentos de polihistidina. El pRSET-HAL se analizó por medio de un análisis con enzimas de restricción y por secuenciación de DNA para confirmar su correcta orientación así como tambièn su secuencia nucleotídica. La histidasa nativa hepática fue tambièn purificada y tuvo un Mr de 72 kDa. A partir de la enzima purificada nativa se preparó un antisuero contra la histidasa en conejo. El análisis por Western blot mostró una sola banda de 72 kDa en membranas que contenían histidasa purificada o en la fracción citosólica de hígado de rata. El mismo anticuerpo tambièn detectó en lisados de E. coli transformados con el plásmido pRSET-HAL una sola banda de 74 kDa correspondientes a la histidasa recombinante antes de su hidrólisis con enterocinasa. Despuès de la proteólisis, el análisis por Western blot mostró una sola banda de aproximadamente 72 kDa correspondiente a la histidasa. Análisis cinèticos de la histidasa recombinante mostraron Km y Vmax similares a las observadas con la histidasa nativa.

Histidine-imbalanced diets stimulate hepatic histidase gene expression in rats.

A high protein concentration in the diet induces the gene expression of several amino acid degrading enzymes such as histidase (Hal) in rats. It is important to understand whether the amino acid pattern of the dietary protein affects the gene expression of these enzymes. The purpose of the present work was to study the effect of a histidine-imbalanced diet on the activity and mRNA concentration of rat hepatic histidase. Seven groups of six rats were fed one of the following diets: 1) 6% casein (basal), 2) 20% casein, 3) 35% casein, 4) an imbalance diet containing 6% casein plus a mixture of indispensable amino acids (IAA) equivalent to a 20% casein diet without histidine (I-20), 5) 6% casein plus a mixture of IAA equivalent to a 35% casein diet without histidine (I-35), 6) a corrected diet containing 6% casein plus IAA including histidine equivalent to a 20% casein diet, 7) a corrected diet containing 6% casein plus IAA including histidine equivalent to a 35% casein diet. Serum histidine concentration was inversely proportional to the protein content of the diet, and it was significantly higher in rats fed the corrected diets compared to their respective imbalanced diet groups. Hal activity increased as the protein content of the diet increased. Greater histidine imbalance resulted in lower food intake and higher Hal activity. Rats fed histidine-corrected diets had lower activity than their respective imbalanced groups. Differences in Hal activity were associated with differences in the concentration of Hal mRNA. These results indicate that rats fed a histidine-imbalanced diet exhibit reduced food intake and weight gain and increased Hal gene expression as a consequence of an increased amino acid catabolism.

Reduced locomotor activity of rats made histidinemic by injection of histidine.

Acute histidinemia was provoked in 30-d-old male Wistar rats by injecting intraperitoneally either histidine alone (0.5 mg/g body wt) or histidine (0.25 mg/g body wt) plus the histidase inhibitor nitromethane (0.73 mg/g body wt). Histidase activity was approximately 90% inhibited in rats receiving nitromethane. Serum histidine in both groups reached levels similar to those of histidinemic patients. Rats were subjected to the open field behavioral task, and the number of rearings and crossings were counted. A consistently lower locomotor activity was observed in the histidinemic rats. It is proposed that reduced locomotor activity and its relationship to psychomotor development should be investigated in histidinemic children.