SIRT1 enhances glucose tolerance by potentiating brown adipose tissue function

This is an open access article under the CC BY-NC-ND license.-- et al.[Objective]: SIRT1 has been proposed to be a key signaling node linking changes in energy metabolism to transcriptional adaptations. Although SIRT1 overexpression is protective against diverse metabolic complications, especially in response to high-fat diets, studies aiming to understand the etiology of such benefits are scarce. Here, we aimed to identify the key tissues and mechanisms implicated in the beneficial effects of SIRT1 on glucose homeostasis. [Methods]: We have used a mouse model of moderate SIRT1 overexpression, under the control of its natural promoter, to evaluate glucose homeostasis and thoroughly characterize how different tissues could influence insulin sensitivity. [Results]: Mice with moderate overexpression of SIRT1 exhibit better glucose tolerance and insulin sensitivity even on a low fat diet. Euglycemic-hyperinsulinemic clamps and in-depth tissue analyses revealed that enhanced insulin sensitivity was achieved through a higher brown adipose tissue activity and was fully reversed by housing the mice at thermoneutrality. SIRT1 did not influence brown adipocyte differentiation, but dramatically enhanced the metabolic transcriptional responses to β3-adrenergic stimuli in differentiated adipocytes. [Conclusions]: Our work demonstrates that SIRT1 improves glucose homeostasis by enhancing BAT function. This is not consequent to an alteration in the brown adipocyte differentiation process, but as a result of potentiating the response to β3-adrenergic stimuli.M.S. is funded by the CNIO and by grants from the MICINN (SAF), the Regional Government of Madrid, the European Research Council (CANCER&AGING; LS1, ERC-2008-AdG), the Botín Foundation, the Ramón Areces Foundation, and the AXA Foundation. P.J.F.M. is funded by the AECC. A.M.V. is funded by the following grant support: SAF2012-33283 (MINECO, Spain), Comunidad de Madrid S2010/BMD-2423, EFSD and Amylin Paul Langerhans Grant and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM, ISCIII, Barcelona, Spain). P.M.G.R. is funded by the following grant support: BFU2011-24679 (MINECO, Spain) and he is a recipient of a Ramon y Cajal contract: RYC-2009-05158(MINECO, Spain).Peer Reviewe

Neuronal induction and bioenergetics characterization of human forearm adipose stem cells from Parkinson’s disease patients and healthy controls

Parkinson's disease; Stem regenerative medicine; BioenergeticsEnfermedad de Parkinson; Medicina regenerativa del tallo; BioenergéticaMalaltia de Parkinson; Medicina regenerativa de tija; BioenergèticaNeurodegenerative diseases, such as Parkinson's disease, are heterogeneous disorders with a multifactorial nature involving impaired bioenergetics. Stem-regenerative medicine and bioenergetics have been proposed as promising therapeutic targets in the neurologic field. The rationale of the present study was to assess the potential of human-derived adipose stem cells (hASCs) to transdifferentiate into neuronal-like cells (NhASCs and neurospheres) and explore the hASC bioenergetic profile. hASC neuronal transdifferentiation was performed through neurobasal media and differentiation factor exposure. High resolution respirometry was assessed. Increased MAP-2 neuronal marker protein expression upon neuronal induction (p<0.05 undifferentiated hASCs vs. 28-36 days of differentiation) and increased bIII-tubulin neuronal marker protein expression upon neuronal induction (p<0.05 undifferentiated hASCs vs. 6-28-36 days of differentiation) were found. The bioenergetic profile was detectable through high-resolution respirometry approaches in hASCs but did not lead to differential oxidative capacity rates in healthy or clinically diagnosed PD-hASCs. We confirmed the capability of transdifferentiation to the neuronal-like profile of hASCs derived from the forearms of human subjects and characterized the bioenergetic profile. Suboptimal maximal respiratory capacity trends in PD were found. Neuronal induction leading to positive neuronal protein expression markers is a relevant issue that encourages the suitability of NhASC models in neurodegeneration

MRI phenotypes with high neurodegeneration are associated with peripheral blood B-cell changes

Postprint (author's final draft

Integrin-targeted delivery into cancer cells of a Pt(IV) pro-drug through conjugation to RGD-containing peptides

Conjugates of a Pt(IV) derivative of picoplatin with monomeric (Ptc(RGDfK), 5) and tetrameric (PtRAFT-{c(RGDfK)}4, 6) RGD-containing peptides were synthesized with the aim of exploiting their selectivity and high affinity for αVβ3 and αVβ5 integrins for targeted delivery of this anticancer metallodrug to tumor cells overexpressing these receptors. Solid- and solution-phase approaches in combination with click chemistry were used for the preparation of the conjugates, which were characterized by high resolution ESI MS and NMR. αVβ3 and αVβ5 integrin expression was evaluated in a broad panel of human cancer and nonmalignant cells. SK-MEL-28 melanoma cells were selected based on the high expression levels of both integrins, while CAPAN-1 pancreatic cancer cells and 1BR3G fibroblasts were selected as the negative control. Internalization experiments revealed a good correlation between integrin expression and the celular uptake of the corresponding fluorescein-labeled peptides and that the internalization capacity of the tetrameric RGD-containing peptide was considerably higher than that of the monomeric one. Cytotoxic experiments indicated that the antitumor activity of picoplatin in melanoma cells was increased by 2.6-fold when its Pt(IV) derivative was conjugated to c(RGDfK) (IC50 = 12.8 ± 2.1 μM) and by 20-fold when conjugated to RAFT-{c(RGDfK)}4 (IC50 = 1.7 ± 0.6 μM). In contrast, the cytotoxicity of the conjugates was inhibited in control cells lacking αVβ3 and αVβ5 integrin expression. Finally, cellular uptake studies by ICP-MS confirmed a good correlation between the levels of expression of integrins, intracellular platinum accumulation and antitumor activity. Indeed, accumulation and cytotoxicity were much higher in SK-MEL-28 cells than in CAPAN-1, being particularly higher in the case of the tetrameric conjugate. The overall results highlight that the great ability of RAFT-{c(RGDfK)}4 to bind to and to be internalized by integrins overexpressed in SK-MEL-28 cells results in higher accumulation of the Pt(IV) complex, leading to a high antitumor activity. These studies provide new insights into the potential of targeting αVβ3 and αVβ5 integrins with Pt(IV) anticancer pro-drugs conjugated to tumor-targeting devices based on RGDcontaining peptides, particularly on how multivalency can improve both the selectivity and potency of such metallodrugs by increasing cellular accumulation in tumor tissues

Neuronal induction and bioenergetics characterization of human forearm adipose stem cells from Parkinson's disease patients and healthy controls

Neurodegenerative diseases, such as Parkinson's disease, are heterogeneous disorders with a multifactorial nature involving impaired bioenergetics. Stem-regenerative medicine and bioenergetics have been proposed as promising therapeutic targets in the neurologic field. The rationale of the present study was to assess the potential of human-derived adipose stem cells (hASCs) to transdifferentiate into neuronal-like cells (NhASCs and neurospheres) and explore the hASC bioenergetic profile. hASC neuronal transdifferentiation was performed through neurobasal media and differentiation factor exposure. High resolution respirometry was assessed. Increased MAP-2 neuronal marker protein expression upon neuronal induction (p<0.05 undifferentiated hASCs vs. 28-36 days of differentiation) and increased bIII-tubulin neuronal marker protein expression upon neuronal induction (p<0.05 undifferentiated hASCs vs. 6-28-36 days of differentiation) were found. The bioenergetic profile was detectable through high-resolution respirometry approaches in hASCs but did not lead to differential oxidative capacity rates in healthy or clinically diagnosed PD-hASCs. We confirmed the capability of transdifferentiation to the neuronal-like profile of hASCs derived from the forearms of human subjects and characterized the bioenergetic profile. Suboptimal maximal respiratory capacity trends in PD were found. Neuronal induction leading to positive neuronal protein expression markers is a relevant issue that encourages the suitability of NhASC models in neurodegeneration

SIRT1 enhances glucose tolerance by potentiating brown adipose tissue function

Objective: SIRT1 has been proposed to be a key signaling node linking changes in energy metabolism to transcriptional adaptations. Although SIRT1 overexpression is protective against diverse metabolic complications, especially in response to high-fat diets, studies aiming to understand the etiology of such benefits are scarce. Here, we aimed to identify the key tissues and mechanisms implicated in the beneficial effects of SIRT1 on glucose homeostasis. Methods: we have used a mouse model of moderate SIRT1 overexpression, under the control of its natural promoter, to evaluate glucose homeostasis and thoroughly characterize how different tissues could influence insulin sensitivity. Results: mice with moderate overexpression of SIRT1 exhibit better glucose tolerance and insulin sensitivity even on a low fat diet. Euglycemic-hyperinsulinemic clamps and in-depth tissue analyses revealed that enhanced insulin sensitivity was achieved through a higher brown adipose tissue activity and was fully reversed by housing the mice at thermoneutrality. SIRT1 did not influence brown adipocyte differentiation, but dramatically enhanced the metabolic transcriptional responses to β3-adrenergic stimuli in differentiated adipocytes. Conclusions: our work demonstrates that SIRT1 improves glucose homeostasis by enhancing BAT function. This is not consequent to an alteration in the brown adipocyte differentiation process, but as a result of potentiating the response to β3-adrenergic stimuli

Unraveling Inclusion Body Myositis Using a Patient-derived Fibroblast Model

Background: Inclusion body myositis (IBM) is an inflammatory myopathy clinically characterized by proximal and distal muscle weakness, with inflammatory infiltrates, rimmed vacuoles and mitochondrial changes in muscle histopathology. There is scarce knowledge on IBM aetiology, and non-established biomarkers or effective treatments are available, partly due to the lack of validated disease models. Methods: We have performed transcriptomics and functional validation of IBM muscle pathological hallmarks in fibroblasts from IBM patients (n = 14) and healthy controls (n = 12), paired by age and sex. The results comprise an mRNA-seq, together with functional inflammatory, autophagy, mitochondrial and metabolic changes between patients and controls. Results: Gene expression profile of IBM vs control fibroblasts revealed 778 differentially expressed genes (P-value adj < 0.05) related to inflammation, mitochondria, cell cycle regulation and metabolism. Functionally, an increased inflammatory profile was observed in IBM fibroblasts with higher supernatant cytokine secretion (three-fold increase). Autophagy was reduced considering basal protein mediators (18.4% reduced), time-course autophagosome formation (LC3BII 39% reduced, P-value < 0.05), and autophagosome microscopic evaluation. Mitochondria displayed reduced genetic content (by 33.9%, P-value < 0.05) and function (30.2%-decrease in respiration, 45.6%-decline in enzymatic activity (P-value < 0.001), 14.3%-higher oxidative stress, 135.2%-increased antioxidant defence (P-value < 0.05), 11.6%-reduced mitochondrial membrane potential (P-value < 0.05) and 42.8%-reduced mitochondrial elongation (P-value < 0.05)). In accordance, at the metabolite level, organic acid showed a 1.8-fold change increase, with conserved amino acid profile. Correlating to disease evolution, oxidative stress and inflammation emerge as potential markers of prognosis. Conclusions: These findings confirm the presence of molecular disturbances in peripheral tissues from IBM patients and prompt patients’ derived fibroblasts as a promising disease model, which may eventually be exported to other neuromuscular disorders. We additionally identify new molecular players in IBM associated with disease progression, setting the path to deepen in disease aetiology, in the identification of novel biomarkers or in the standardization of biomimetic platforms to assay new therapeutic strategies for preclinical studies

Chitinase 3-like 1: prognostic biomarker in clinically isolated syndromes

Prognostic molecular biomarkers for the conversion of clinically isolated syndrome (CIS) to multiple sclerosis (MS) are lacking. In a prospective longitudinal study of 813 individuals with CIS, Cantó et al. validate elevated CSF levels of chitinase 3-like 1 as a biomarker for conversion to MS and development of disabilit

Systematic Collaborative Reanalysis of Genomic Data Improves Diagnostic Yield in Neurologic Rare Diseases

Altres ajuts: Generalitat de Catalunya, Departament de Salut; Generalitat de Catalunya, Departament d'Empresa i Coneixement i CERCA Program; Ministerio de Ciencia e Innovación; Instituto Nacional de Bioinformática; ELIXIR Implementation Studies (CNAG-CRG); Centro de Investigaciones Biomédicas en Red de Enfermedades Raras; Centro de Excelencia Severo Ochoa; European Regional Development Fund (FEDER).Many patients experiencing a rare disease remain undiagnosed even after genomic testing. Reanalysis of existing genomic data has shown to increase diagnostic yield, although there are few systematic and comprehensive reanalysis efforts that enable collaborative interpretation and future reinterpretation. The Undiagnosed Rare Disease Program of Catalonia project collated previously inconclusive good quality genomic data (panels, exomes, and genomes) and standardized phenotypic profiles from 323 families (543 individuals) with a neurologic rare disease. The data were reanalyzed systematically to identify relatedness, runs of homozygosity, consanguinity, single-nucleotide variants, insertions and deletions, and copy number variants. Data were shared and collaboratively interpreted within the consortium through a customized Genome-Phenome Analysis Platform, which also enables future data reinterpretation. Reanalysis of existing genomic data provided a diagnosis for 20.7% of the patients, including 1.8% diagnosed after the generation of additional genomic data to identify a second pathogenic heterozygous variant. Diagnostic rate was significantly higher for family-based exome/genome reanalysis compared with singleton panels. Most new diagnoses were attributable to recent gene-disease associations (50.8%), additional or improved bioinformatic analysis (19.7%), and standardized phenotyping data integrated within the Undiagnosed Rare Disease Program of Catalonia Genome-Phenome Analysis Platform functionalities (18%)

Búsqueda de Biomarcadores asociados a la conversión a esclerosis múltiple en pacientes con síndromes clínicos aislados

Aproximadamente el 85% de los pacientes con esclerosis múltiple (EM) inician la enfermedad con un síndrome clínico aislado (CIS), pero se ha descrito que entre un 30 y un 85% de los pacientes que presentan un CIS finalmente desarrollan EM clínicamente definida (EMCD). Actualmente se utilizan la presencia de alteraciones en la resonancia magnética (RM) y la detección de bandas oligoclonales en el líquido cefalorraquídeo (LCR) como marcadores pronósticos en los pacientes con CIS. Aparte de estos factores, la evidencia sobre el posible papel de otros biomarcadores moleculares ha sido controvertida por falta de validación de los resultados. Con este objetivo llevamos a cabo la presente tesis doctoral. Mediante un abordaje de proteómica en pooles de muestras de LCR de pacientes con CIS que convertían a EMCD y pacientes que permanecían como CIS se buscaron proteínas asociadas a la conversión a EM. Las proteínas que se encontraron expresadas de forma diferencial se validaron en muestras individuales mediante técnicas alternativas como el ELISA y selected reaction monitoring (SRM). De las proteínas validadas se seleccionó la chitinase 3-like 1 (CHI3L1) para su validación en una cohorte independiente y numerosa de pacientes con CIS. Además, se determinó su expresión en plasma en las diferentes formas clínicas de la enfermedad y se estudió la asociación entre un polimorfismo en el promotor del gen de la CHI3L1 y la EM. Por otro lado, se estudió la expresión de la CHI3L1 en tejido cerebral de pacientes con EM así como en las poblaciones celulares del LCR. Finalmente, se realizó el modelo animal de la enfermedad, la encefalomielitis autoinmune experimental (EAE) en ratones knockout (KO) y wild-type (WT) para la CHI3L1 y se realizaron estudios histopatológicos y ensayos de proliferación para determinar la función de la proteína en la respuesta inmune. De las proteínas encontradas en el estudio de proteómica se validaron como biomarcadores asociados a la conversión a EM la CHI3L1, la semaforina 7A y la CNDP1. La CHI3L1 además, se validó en una cohorte numerosa de pacientes con CIS, encontrándose además una correlación entre los niveles de CHI3L1 y el tiempo de conversión y el tiempo hasta alcanzar un EDSS de 3. Por otro lado, los niveles plasmáticos de CHI3L1 se encontraron incrementados en los pacientes con formas progresivas de la enfermedad respecto a los controles sanos y los pacientes con formas recurrentes. Además, se encontró una asociación entre un polimorfismo en el promotor del gen de la CHI3L1 y las formas progresivas de la enfermedad. Cuando se estudió el papel de la proteína en el modelo animal no se observaron diferencias en la gravedad del curso clínico entre los ratones WT y KO para la proteína. Tampoco se encontraron diferencias a nivel histopatológico ni en la respuesta inmune. Con los resultados obtenidos se puede concluir que la CHI3L1, semaforina 7A y CNDP1 se han validado como biomarcadores asociados con la conversión a EMCD, y que los niveles de CHI3L1 en LCR tienen además claras implicaciones pronósticas en los pacientes con CIS. A diferencia del LCR, los niveles de CHI3L1 en plasma no parecen reflejar el grado de inflamación que tiene lugar en le SNC de los pacientes con EM, y se asocian con las formas progresivas de la enfermedad. Finalmente, los estudios realizados en el modelo animal de EM no sugieren un papel inmunoregulador de la CHI3L1, en cuanto a que la eliminación del gen Brp-39 en ratones no se asoció con cambios en el curso clínico de la EAE, cambios histopatológicos, o alteraciones en las respuestas inmunitarias.In about 85% of patients with multiple sclerosis (MS) the disease starts with a clinically isolated syndrome (CIS), but only 30 to 85% of patients with CIS finally develop clinically definite MS (CDMS). At present, only magnetic resonance (MR) abnormalities and presence of oligoclonal bands (BOC) in the cerebrospinal fluid (CSF) are used as prognostic biomarkers in CIS patients. Apart from these, the role of other molecular biomarkers is still controversial due to lack of validation. This thesis was conducted with the aim to identify and validate additional molecular biomarkers associated with the conversion to MS. A proteomic study with pooled CSF samples from patients with CIS who converted to CDMS and patients who remained as CIS was performed to identify biomarkers associated with conversion to MS. Those proteins that were found differentially expressed between groups were validated in individual samples by means of alternative techniques such as ELISA and selected reaction monitoring (SRM). Among the validated proteins, chitinase 3-like 1 (CHI3L1) was selected for validation in a large cohort of CIS patients. Furthermore, CHI3L1 levels were determined in plasma from patients with different clinical forms and a polymorphism in the promoter region of the CHI3L1 gene was investigated for its potential association with the disease. Additionally, the cell source of CHI3L1 was studied in brain tissue and CSF samples from MS patients. Finally, the animal model of the disease, the experimental autoimmune encephalomyelitis (EAE) was induced in wild-type (WT) and knock-out (KO) mice for the CHI3L1 protein. Histopathological and proliferative response studies were performed to assess the role of the protein in the immune response. Amongst the proteins obtained in the proteomics study only CHI3L1, semaphorin 7A and CDNP1 were validated. Furthermore, CHI3L1 was validated in a large cohort of CIS patients. A correlation between CSF CHI3L1 levels and time to conversion and time to EDSS 3 was also found. On the other hand, plasma levels of CHI3L1 were found increased in patients with progressive forms of MS compared to healthy controls and patients with relapse-onset. Additionally there was an association between the studied polymorphism and the progressive forms of the disease. When the protein role in the disease was studied in EAE no differences were observed in the clinical course between WT and KO mice. Also, no differences were found regarding the histopathology and the immune response. In conclusion the aggregate results confirm CHI3L1, semaphorin 7A and CNDP1 as biomarkers associated with conversion to CDMS in CIS patients, and CHI3L1 CSF levels also have clear prognostic implications in CIS patients. In contrast to CSF, plasma levels of CHI3L1 are not reflecting the inflammation degree in the CNS in patients with MS, and are associated with the progressive forms of the disease. Finally, the studies performed in the animal model of MS do not suggest an immunoregulatory role of CHI3L1, since the elimination of the Brp-39 gene is not associated with changes in the clinical course, histopathology or immune response