Eulalia Garrido-Magaña

Drug Development in Conformational Diseases: A Novel Family of Chemical Chaperones that Bind and Stabilise Several Polymorphic Amyloid Structures

The increasing prevalence of conformational diseases, including Alzheimers disease, type 2 Diabetes Mellitus and Cancer, poses a global challenge at many different levels. It has devastating effects on the sufferers as well as a tremendous economic impact on families and the health system. In this work, we apply a cross-functional approach that combines ideas, concepts and technologies from several disciplines in order to study, in silico and in vitro, the role of a novel chemical chaperones family (NCHCHF) in processes of protein aggregation in conformational diseases. Given that Serum Albumin (SA) is the most abundant protein in the blood of mammals, and Bovine Serum Albumin (BSA) is an off-the-shelf protein available in most labs around the world, we compared the ligandability of BSA:NCHCHF with the interaction sites in the Human Islet Amyloid Polypeptide (hIAPP):NCHCHF, and in the amyloid pharmacophore fragments (Aβ17–42 and Aβ16–21):NCHCHF. We posit that the merging of this interaction sites is a meta-structure of pharmacophore which allows the development of chaperones that can prevent protein aggregation at various states from: stabilizing the native state to destabilizing oligomeric state and protofilament. Furthermore to stabilize fibrillar structures, thus decreasing the amount of toxic oligomers in solution, as is the case with the NCHCHF. The paper demonstrates how a set of NCHCHF can be used for studying and potentially treating the various physiopathological stages of a conformational disease. For instance, when dealing with an acute phase of cytotoxicity, what is needed is the recruitment of cytotoxic oligomers, thus chaperone F, which accelerates fiber formation, would be very useful; whereas in a chronic stage it is better to have chaperones A, B, C, and D, which stabilize the native and fibril structures halting self-catalysis and the creation of cytotoxic oligomers as a consequence of fiber formation. Furthermore, all the chaperones are able to protect and recondition the cerebellar granule cells (CGC) from the cytotoxicity produced by the hIAPP20–29 fragment or by a low potassium medium, regardless of their capacity for accelerating or inhibiting in vitro formation of fibers. In vivo animal experiments are required to study the impact of chemical chaperones in cognitive and metabolic syndromes.

Novel insight into streptozotocin-induced diabetic rats from the protein misfolding perspective

Protein folding is a process of self-assembly defined by the sequence of the amino acids of the protein involved. Additionally, proteins tend to unfold, misfold and aggregate due to both intrinsic and extrinsic causes. Human islet amyloid polypeptide (hIAPP) aggregation is an early step in diabetes mellitus. However, the aggregation of rat IAPP (rIAPP) remains an open question. Adult female Sprague-Dawley rats weighing 150–250 g were divided into two groups. The experimental group (streptozotocin [STZ]) (n = 21) received an intraperitoneal injection of a single dose of 40 mg/kg STZ. We used the mouse anti-IAPP antibody and the anti-amyloid oligomer antibody to study the temporal course of rIAPP oligomerization during STZ-induced diabetes using a wide array of methods, strategies and ideas derived from biochemistry, cell biology, and proteomic medicine. Here, we demonstrated the tendency of rIAPP to aggregate and trigger cooperative processes of self-association or hetero-assembly that lead to the formation of amyloid oligomers (trimers and hexamers). Our results are the first to demonstrate the role of rIAPP amyloid oligomers in the development of STZ-induced diabetes in rats. The IAPP amyloid oligomers are biomarkers of the onset and progression of diabetes and could play a role as therapeutic targets.

Resistin levels are not associated with obesity in central precocious puberty

Objective: To compare serum resistin concentrations between prepubertal girls with a BMI > 85th percentile and girls with precocious puberty (CPP) who have and have not undergone GnRH analog treatment. Patients and methods: This is a cross‐sectional study in girls with a BMI > 85th percentile and a median age of 8 years. We included 31 girls with CPP who did not receive treatment (CPPoT), 23 girls with CPP who were treated with leuprolide (CPPT), 22 prepubertal girls and 24 pubertal girls. Anthropometric data and the fasting plasma concentrations of lipids, glucose, insulin, and resistin were measured. Results: The z‐BMI scores were similar among the groups (p = 0.344), and body fat percentage (BF%) was similar among CPPT, CPPoT and prepubertal girls (p = 0.151). Resistin and insulin levels were lower in girls with CPP (CPPT and CPPoT) than in prepubertal and pubertal girls (median resistin level: CPPT 11.8 pg/ml vs CPPoT 11 pg/ml vs prepubertal 16 pg/ml vs pubertal 16 pg/ml, p = 0.001; median insulin level: CPPT 10.7 &mgr;UI/mL vs CPPoT 10.2 &mgr;UI/mL vs prepubertal 14.4 &mgr;UI/mL vs pubertal 32 &mgr;UI/mL p = 0.02). ANCOVA analysis, after adjustments for pubertal stage, BF% and z‐BMI, showed that CPP modifies resistin levels (F = 31.4; p = 0.0001) independently of these parameters (p < 0.05). Conclusions: In the group of girls with overweight or obesity, the resistin level was lower in girls with CPP than in prepubertal and pubertal girls. More studies are needed to understand the role of resistin in CPP patients. HIGHLIGHTSThis study is the first to determine resistin levels in patients with CPP.CPP patients have lower concentrations of resistin than prepubertal and pubertal girls with overweight or obesity without CPP.Resistin levels were not found to be related to z‐BMI, body fat percentage or CPP treatment status.

Diabetes Drug Discovery: hIAPP1–37 Polymorphic Amyloid Structures as Novel Therapeutic Targets

Human islet amyloid peptide (hIAPP1–37) aggregation is an early step in Diabetes Mellitus. We aimed to evaluate a family of pharmaco-chaperones to act as modulators that provide dynamic interventions and the multi-target capacity (native state, cytotoxic oligomers, protofilaments and fibrils of hIAPP1–37) required to meet the treatment challenges of diabetes. We used a cross-functional approach that combines in silico and in vitro biochemical and biophysical methods to study the hIAPP1–37 aggregation-oligomerization process as to reveal novel potential anti-diabetic drugs. The family of pharmaco-chaperones are modulators of the oligomerization and fibre formation of hIAPP1–37. When they interact with the amino acid in the amyloid-like steric zipper zone, they inhibit and/or delay the aggregation-oligomerization pathway by binding and stabilizing several amyloid structures of hIAPP1–37. Moreover, they can protect cerebellar granule cells (CGC) from the cytotoxicity produced by the hIAPP1–37 oligomers. The modulation of proteostasis by the family of pharmaco-chaperones A–F is a promising potential approach to limit the onset and progression of diabetes and its comorbidities.

Asociación de leptina con factores cardiometabólicos en escolares y adolescentes con hiperplasia suprarrenal congénita

espanolIntroduccion: En la hiperplasia suprarrenal congenita (HSC), la obesidad, la hiperinsulinemia y los niveles de leptina se encuentran incrementados. Objetivo: Identificar la frecuencia de los factores de riesgo cardiometabolico (FRC) en ninos y adolescentes con HSC y explorar la relacion con los niveles de leptina. Metodo: Estudio transversal de 40 pacientes a quienes se realizo somatometria y evaluacion de glucosa, insulina, trigliceridos, 17-hidroxiprogesterona, leptina, colesterol HDL y LDL en ayuno. Los pacientes fueron clasificados por el numero de FRC y se analizaron los niveles de leptina con Kruskal-Wallis. Se aplico correlacion de Pearson entre la leptina, puntuacion Z del indice de masa corporal (zIMC) y porcentaje de grasa corporal. Resultados: 50 % de los pacientes presento obesidad y sobrepeso, 59 % hipertrigliceridemia, 40 % hipoalfalipoproteinemia, 27.5 % colesterol LDL alto y 22.5 % resistencia a la insulina. Hubo correlacion positiva entre leptina y porcentaje de grasa corporal (r = 0.64), el zIMC (r = 0.55) y el numero de FRC (r = 0.65). En el analisis multivariado ajustado por obesidad, los niveles de leptina se asociaron con el numero de FRC. Conclusion: La HSC tuvo alta frecuencia de FRC y al parecer la leptina se asocio con perfil cardiometabolico mas adverso en sujetos con obesidad y sobrepeso. EnglishIntroduction: In congenital adrenal hyperplasia (CAH), obesity, hyperinsulinemia and leptin levels are increased. Objective: To identify the frequency of cardiometabolic risk factors (CRF) in children and adolescents with CAH and to explore the relationship with leptin levels. Method: Cross-sectional study of 40 patients who underwent anthropometric measurements and had fasting glucose, insulin, triglycerides, 17-hidroxyprogesterone, leptin, HDL and LDL-cholesterol assessed. The patients were classified according to the number of CRFs, and leptin levels were analyzed with the Kruskal-Wallis test. Pearson’s correlation was applied between leptin, body mass index (BMI) z-score and body fat percentage. Results: Fifty percent of the patients had obesity and overweight, 59% had hypertriglyceridemia, 40%, hypoalphalipoproteinemia, 27.5%, high LDL-cholesterol and 22.5% insulin resistance. There was positive correlation between leptin and body fat percentage (r = 0.64), BMI z-score (r = 0.55) and the number of CRFs (r = 0.65). In the obesity-adjusted multivariate analysis, leptin levels were associated with the number of CRFs. Conclusion: CAH had a high frequency of CRFs and leptin appeared to be associated with a more adverse cardiometabolic profile in subjects with obesity and overweight.

Influence of the informal primary caretaker on glycemic control among prepubertal pediatric patients with type 1 diabetes mellitus

Objectives In prepubertal type 1 diabetic patients (DM1), the availability of an informal primary caregiver (ICP) is critical to making management decisions; in this study, the ICP-related risk factors associated with glycemic control were identified.

Original articleInfluence of the informal primary caretaker on glycemic control among prepubertal pediatric patients with type 1 diabetes mellitusInfluência do cuidador familiar principal sobre o controle glicêmico entre pacientes pediátricos pré-púberes com diabetes mellitus tipo 1☆

Objectives In prepubertal type 1 diabetic patients (DM1), the availability of an informal primary caregiver (ICP) is critical to making management decisions; in this study, the ICP-related risk factors associated with glycemic control were identified.

RELATIONSHIP BETWEEN SERUM LEPTIN LEVELS AND WEIGHT GAIN IN GIRLS WITH CENTRAL PRECOCIOUS PUBERTY AT 1-YEAR FOLLOW-UP

OBJECTIVE Patients with central precocious puberty (CPP) may have increased serum leptin levels; however, it is not well known whether this increase differs between patients with and without obesity. Our objectives were to describe the changes in serum leptin in girls with CPP in the first 12 months after diagnosis based on body mass index (BMI) and to explore whether serum leptin level at CPP diagnosis is related to BMI z-score (BMIz) after a 1-year follow-up. METHODS A prospective cohort study was performed. We included 42 girls with idiopathic CPP in Tanner stages II and III. Anthropometric measurements were performed, and serum leptin was measured at study initiation and after 12 months. Patients were stratified according to BMI category (30 with a BMI in the <94th percentile and 12 with a BMI in the >95th percentile). Study variables were compared. Correlations among leptin, BMIz, and body fat were assessed. RESULTS Leptin increased gradually during the first year of treatment. In girls with a BMI in the <94th percentile at diagnosis, body fat percentage increased gradually during the first year of follow-up. CONCLUSION Girls with a BMI in the <94th percentile have a greater risk of weight increase. Leptin level >10.5 ng/dL at diagnosis is a risk factor for weight gain after 1 year. ABBREVIATIONS BMI = body mass index BMIz = BMI z-score CPP = central precocious puberty GnRHa = gonadotropin-releasing hormone analogue.