Laura Elia Martínez de Villarreal

PSMB8 Encoding the β5i Proteasome Subunit Is Mutated in Joint Contractures, Muscle Atrophy, Microcytic Anemia, and Panniculitis-Induced Lipodystrophy Syndrome

We performed homozygosity mapping in two recently reported pedigrees from Portugal and Mexico with an autosomal-recessive autoinflammatory syndrome characterized by joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy (JMP). This revealed only one homozygous region spanning 2.4 Mb (5818 SNPs) on chromosome 6p21 shared by all three affected individuals from both families. We directly sequenced genes involved in immune response located in this critical region, excluding the HLA complex genes. We found a homozygous missense mutation c.224C>T (p.Thr75Met) in the proteasome subunit, beta-type, 8 (PSMB8) gene in affected patients from both pedigrees. The mutation segregated in an autosomal-recessive fashion and was not detected in 275 unrelated ethnically matched healthy subjects. PSMB8 encodes a catalytic subunit of the 20S immunoproteasomes called β5i. Immunoproteasome-mediated proteolysis generates immunogenic epitopes presented by major histocompatibility complex (MHC) class I molecules. Threonine at position 75 is highly conserved and its substitution with methionine disrupts the tertiary structure of PSMB8. As compared to normal lymphoblasts, those from an affected patient showed significantly reduced chymotrypsin-like proteolytic activity mediated by immunoproteasomes. We conclude that mutations in PSMB8 cause JMP syndrome, most probably by affecting MHC class I antigen processing.

Folate levels and N(5),N(10)-methylenetetrahydrofolate reductase genotype (MTHFR) in mothers of offspring with neural tube defects: a case-control study.

BACKGROUND Neural tube defects (NTDs) have been associated with biochemical factors involved in the conversion of homocysteine to methionine as folate deficiency and the mutation 677T in the N(5),N(10)-methylenetetrahydrofolate reductase gene (MTHFR). METHODS A case-control study was performed to detect this mutation in 38 unrelated women with NTD deceased products and 31 mothers without antecedents of NTD offspring. All products were born in Nuevo León (northeastern Mexico) during 1997. Erythrocyte and plasmatic folate levels and the genotype of the 677 polymorphism at the MTHFR locus were analyzed in both groups. RESULTS Although no significant differences were found in mean blood folate levels, the percentage of women in the case group with erythrocyte folate levels <160 ng/mL was significantly higher than in the control group (75 vs. 51.2%, p <0.05). The proportion of women with plasma folate levels <3.5 ng/mL was higher in the case group (16.2 vs. 0%, p <0.01). Genotype analysis demonstrated a significantly higher proportion of 677T homozygous mothers with NTD products (39.6 vs. 9.1%, p <0.05). Allele frequencies for the 677T mutation were 0.55 and 0.36 for cases and controls, respectively. The odds ratio (OR) for having a NTD product was 6.1 (95%, CI 1.56-23.6) for homozygous 677T mothers vs. homozygous 677C and heterozygous mothers. Significantly low levels of erythrocyte folate were found in the 677C homozygous case group and in plasma folate in the 677C/677T heterozygous case mothers. CONCLUSIONS Our study suggests that folate deficiency and MTHFR unfavorable genotype in mothers are important risk factors for severe NTD phenotype in our population.

An Autosomal Recessive Syndrome of Joint Contractures, Muscular Atrophy, Microcytic Anemia, and Panniculitis-Associated Lipodystrophy

CONTEXT Genetic lipodystrophies are rare disorders characterized by partial or complete loss of adipose tissue and predisposition to insulin resistance and its complications such as diabetes mellitus, hypertriglyceridemia, hepatic steatosis, acanthosis nigricans, and polycystic ovarian syndrome. OBJECTIVE The objective of the study was to report a novel autosomal recessive lipodystrophy syndrome. RESULTS We report the detailed phenotype of two males and one female patient, 26-34 yr old, belonging to two pedigrees with an autosomal recessive syndrome presenting with childhood-onset lipodystrophy, muscle atrophy, severe joint contractures, erythematous skin lesions, and microcytic anemia. Other variable clinical features include hypergammaglobulinemia, hepatosplenomegaly, generalized seizures, and basal ganglia calcification. None of the patients had diabetes mellitus or acanthosis nigricans. Two had mild hypertriglyceridemia and all had low levels of high-density lipoprotein cholesterol. Skin biopsy of an erythematous nodular skin lesion from one of the patients revealed evidence of panniculitis. The lipodystrophy initially affected the upper body but later became generalized involving abdomen and lower extremities as well. CONCLUSIONS We conclude that these patients represent a novel autoinflammatory syndrome resulting in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy. The molecular genetic basis of this disorder remains to be elucidated.

In vitro selective toxicity of toxin T-514 from Karwinskia humboldtiana (buckthorn) plant on various human tumor cell lines.

Toxin T-514 is a dimeric anthracenone isolated from the Karwinskia humboldtiana (buckthorn) plant. Its potential anti-neoplastic effect was evaluated in vitro and the results obtained were compared with the effect of other known anti-cancer agents. Normal and malignant continuous cell lines were tested. After a 72-h exposure, neoplastic cells derived from hepatic, pulmonary and colonic tissues were more sensitive to toxin T-514 than normal cells from the corresponding organ. Hepatoma cells and colon adenocarcinoma CT50 values were < 10 micrograms/ml. Lung adenocarcinoma, undifferentiated bronchogenic cancer cells and small cell carcinoma CT50 values were < 20 micrograms/ml. All benign cell CT50 levels tested were > 113 micrograms/ml. This in vitro selective toxicity found with toxin T-514 was also seen with 5-fluororacil and mitomycin for colon adenocarcinoma and with epidoxorubicin for undifferentiated bronchogenic cancer cells.

Plasma and urine metabolic profiles are reflective of altered beta-oxidation in non-diabetic obese subjects and patients with type 2 diabetes mellitus

ObjectivesThe two primary pathophysiological characteristics of patients with type 2 diabetes mellitus (T2DM) are insulin resistance (IR) and beta cell dysfunction. It has been proposed that the development of IR is secondary to the accumulation of triacylglycerols and fatty acids in the muscle and liver, which is in turn thought to be secondary to an enzymatic defect in mitochondrial beta-oxidation. The purpose of the present study was to analyze the molecules of intermediary metabolism to determine if an alteration in mitochondrial function exists in T2DM patients and, if so, to determine whether this alteration is caused by excess nutrients or an enzymatic defect.Design and methodsSeventy-seven subjects were recruited and divided into four groups (21 T2DM patients, 17 non-diabetic overweight/obese subjects, 20 offspring of T2DM patients, and 19 healthy subjects). Anthropometric parameters were determined by air plethysmography, and biochemical and metabolic parameters were measured, including 31 acylcarnitines (ACs) and 13 amino acids quantified by MS/MS and 67 organic acids measured by GC/MS.ResultsPatients with T2DM showed elevation of short-chain ACs (C2, C4), a glycogenic amino acid (valine), a glycogenic and ketogenic amino acid (tyrosine), and a ketogenic amino acid (leucine) as well as altered excretion of dicarboxylic acids. T2DM offspring with abnormal glucose tolerance test GTT showed increased levels of C16. Subjects in the obese group who were dysglycemic also showed altered urinary excretion of dicarboxylic acids and lower levels of a long-chain AC (C14:2).ConclusionsThese results suggest that mitochondrial beta-oxidation is altered in T2DM patients and that the alteration is most likely caused by nutrient overload through a different pathway from that observed in obese subjects.

Ring 2 chromosome associated with failure to thrive, microcephaly and dysmorphic facial features.

We report here a child with a ring chromosome 2 [r(2)] associated with failure to thrive, microcephaly and dysmorphic features. The chromosomal aberration was defined by chromosome microarray analysis, revealing two small deletions of 2p25.3 (139 kb) and 2q37.3 (147 kb). We show the clinical phenotype of the patient, using a conventional approach and the molecular cytogenetics of a male with a history of prenatal intrauterine growth restriction (IUGR), failure to thrive, microcephaly and dysmorphic facial features. The phenotype is very similar to that reported in other clinical cases with ring chromosome 2.

Matched sibling donors versus alternative donors in allogeneic hematopoietic stem cell transplantation for pediatric severe aplastic anemia in México

Abstract Objectives Hematopoietic stem cell transplantation (HSCT) from a matched sibling donor (MSD) is the preferred initial treatment for children with severe aplastic anemia (SAA). Unfortunately, only about 30% of patients have a suitable human leukocyte antigen-matched sibling. Methods We have analyzed the outcome of 42 patients who received HSCT (22 MSD and 20 alternative donors (AD)) for SAA at the seven major pediatric HSCT centers in Mexico between 2001 and 2013. Results With a median follow-up of 30 months (range, 0.4–144), the 5-year overall survival in children transplanted from MSD was 86.4 + 7.3 vs. 49.5 + 11% for children after AD-HSCT (P = 0.013). The cumulative incidence of treatment-related mortality (TRM) was in the MSD-HSCT 9.1 + 3.9% vs. 47.6 + 9.1% in the AD-HSCT context (P = 0.007). Infectious complications contributed to death (91%) of most patients who received AD-HSCT. Discussion Even when the results of patients given MSD-HSCT are adequate, there is still much room for improvement particularly in children allografted with AD and in the supportive care. The development of an economicwise designed prospective project with MSD or matched unrelated donor HSCTs as a first line of treatment of children with SAA as a unified national trial could address these issues.

Profiles of Amino Acids and Acylcarnitines Related with Insecticide Exposure in Culex quinquefasciatus (Say).

Culex quinquefasciatus Say is a vector of many pathogens of humans, and both domestic and wild animals. Personal protection, reduction of larval habitats, and chemical control are the best ways to reduce mosquito bites and, therefore, the transmission of mosquito-borne pathogens. Currently, to reduce the risk of transmission, the pyrethroids, and other insecticide groups have been extensively used to control both larvae and adult mosquitoes. In this context, amino acids and acylcarnitines have never been associated with insecticide exposure and or insecticide resistance. It has been suggested that changes in acylcarnitines and amino acids profiles could be a powerful diagnostic tool for metabolic alterations. Monitoring these changes could help to better understand the mechanisms involved in insecticide resistance, complementing the strategies for managing this phenomenon in the integrated resistance management. The purpose of the study was to determine the amino acids and acylcarnitines profiles in larvae of Cx. quinquefasciatus after the exposure to different insecticides. Bioassays were performed on Cx. quinquefasciatus larvae exposed to the diagnostic doses (DD) of the insecticides chlorpyrifos (0.001 μg/mL), temephos (0.002 μg/mL) and permethrin (0.01 μg/mL). In each sample, we analyzed the profile of 12 amino acids and 31 acylcarnitines by LC-MS/MS. A t-test was used to determine statistically significant differences between groups and corrections of q-values. Results indicates three changes, the amino acids arginine (ARG), free carnitine (C0) and acetyl-carnitine (C2) that could be involved in energy production and insecticide detoxification. We confirmed that concentrations of amino acids and acylcarnitines in Cx. quinquefasciatus vary with respect to different insecticides. The information generated contributes to understand the possible mechanisms and metabolic changes occurring during insecticide exposure.

Identification of Four Isoforms of Esterase-5A from Culex quinquefasciatus Say

Abstract. The southern house mosquito, Culex quinquefasciatus Say (Diptera: Culicidae), transmits pathogens and is one of the most important vectors of human disease. The carboxylesterase mosquito genes encoded esterase enzyme involved in the mechanism that provides resistance to insecticides. We amplified by RTPCR four alternative transcripts from the esterase gene not reported previously (A, B, C, and D) from Cx. quinquefasciatus larvae from Monterrey, N.L., northeastern Mexico. Through cDNA sequences, we predicted amino acid sequences used to model the three-dimensional structure of protein isoforms. We determined dN and dS ratios to identify evolutionary forces which lead the family. PCR products were obtained from 5A esterases (1839, 1898, 1894, and 1953 bp). The translation sequence of the PCR products showed polypeptides of 612, 473, 282, and 282 amino acids in length for isoforms A, B, C, and D, respectively. Three exons and two introns were obtained in the analyzed sequences. The study sequences were compared with those previously published showing 98.7, 98.5, 91.5, and 91.5% amino acid similarity for isoforms A, B, C, and D, respectively. The threedimensional models showed that only ORF-D had the three amino acids corresponding to the catalytic triad, while ORF-A and ORF-C lacked one or two of the three amino acids. Esterase genes are under purifying of selection; a clue the members are functional. The processes might be useful in monitoring evolutionary dynamics of known carboxylesterase genes and identifying new carboxylesterase splicing.

Proteomic profile of serum of pregnant women carring a fetus with Down syndrome using nano uplc Q-tof ms/ms technology

AbstractIntroduction: Prenatal diagnosis of Down syndrome (DS) is based on the calculated risk of maternal age, biochemical and ultrasonographic markers and recently by cfDNA. Differences in proteo...Abstract Introduction: Prenatal diagnosis of Down syndrome (DS) is based on the calculated risk of maternal age, biochemical and ultrasonographic markers and recently by cfDNA. Differences in proteomic profiles may give an opportunity to find new biomarkers. Objective: Characterize proteome of serum of mothers carrying DS fetus. Material and methods: Blood serum samples of three groups of women were obtained, (a) 10 non-pregnant, (b) 10 pregnant with healthy fetus by ultrasound evaluation, (c) nine pregnant with DS fetus. Sample preparation was as follows: Albumin/IgG depletion, desalting, and trypsin digestion; the process was performed in nanoUPLC MS/MS. Data analysis was made with Mass Lynx 4.1 and ProteinLynx Global Server 3.0, peptide and protein recognition by MASCOT algorithm and UNIPROT-Swissprot database. Results: Each group showed different protein profiles. Some proteins were shared between groups. Only sera from pregnant women showed proteins related to immune and clot pathways. Mothers with DS fetus had 42 specific proteins. Conclusions: We found a different serum protein profile in mothers carrying DS fetuses that do not reflect expression of genes in the extra chromosome. Further studies will be necessary to establish the role of these proteins in aneuploid fetus and analyze their possible use as potential biomarkers.