Biocompatible and Light-Penetrating Hydrogels for Water Decontamination

Solar light-activated photocatalyst nanoparticles (NPs) are promising environment-friendly low cost tools for water decontamination, but their dispersion in the environment must be minimized. Here, we propose the incorporation of TiO2-NPs (also in combination with graphene platelets) into highly biocompatible hydrogels as a promising approach for the production of photoactive materials for water treatment. We also propose a convenient fluorescence-based method to investigate the hydrogel photocatalytic activity in real time with a conventional fluorimeter. Kinetics analysis of the degradation profile of a target fluorescent model pollutant demonstrates that fast degradation occurs in the matrix bulk. Fluorescence anisotropy proved that small pollutant molecules diffuse freely in the hydrogel. Rheological and scanning electron microscopy characterization showed that the TiO2-NP incorporation does not significantly alter the hydrogel mechanical and morphological properties

Leber's Hereditary Optic Neuropathy (LHON) Pathogenic Mutations Induce Mitochondrial-dependent Apoptotic Death in Transmitochondrial Cells Incubated with Galactose Medium

Leber's hereditary optic neuropathy (LHON), a maternally inherited form of central vision loss, is associated with mitochondrial DNA pathogenic point mutations affecting different subunits of complex I. We here report that osteosarcoma-derived cytoplasmic hybrids (cybrid) cell lines harboring one of the three most frequent LHON pathogenic mutations, at positions 11778/ND4, 3460/ND1, and 14484/ND6, undergo cell death when galactose replaces glucose in the medium, contrary to control cybrids that maintain some growth capabilities. This is a well known way to produce a metabolic stress, forcing the cells to rely on the mitochondrial respiratory chain to produce ATP. We demonstrate that LHON cybrid cell death is apoptotic, showing chromatin condensation and nuclear DNA laddering. Moreover, we also document the mitochondrial involvement in the activation of the apoptotic cascade, as shown by the increased release of cytochrome c into the cytosol in LHON cybrid cells as compared with controls. Cybrids bearing the 3460/ND1 and 14484/ND6 mutations seemed more readily prone to undergo apoptosis as compared with the 11778/ND4 mutation. In conclusion, LHON cybrid cells forced by the reduced rate of glycolytic flux to utilize oxidative metabolism are sensitized to an apoptotic death through a mechanism involving mitochondria

Polytropic Models of Filamentary Molecular Clouds and Sub-Structure Formation in Starless Cores

Recent observations made by the Herschel Space Observatory and the Planck Satellite have shown that molecular clouds are made by networks of filaments, shaped by interstellar turbulence and magnetic fields. We analyse the stability of filamentary molecular clouds with the help of cylindrical polytropic models with and without helical magnetic fields. We then focus on the growth of hydrodynamical density perturbations and the formation of sub-structures and fragments in pre-stellar cores

Effect of hypoxia-inducing ions on chondrogenic differentiation in adipose derived mesenchymal stem cells within alginate matrix

Cartilage is a highly organized tissue with complex biomechanical properties, but since it has a poor intrinsic capacity of self-healing, injuries at this site usually lead to several problems, often ending in disabling symptoms. Although, different approaches have been proposed, even now cartilage repair represents a great challenge for orthopaedic surgeons (1, 2). One of the promising approach is given from tissue engineering, employing the combination of biomaterials and cell therapy to develop new therapeutic strategies. In this paper, we describe the behaviour of human adipose derived mesenchymal stem cells encapsulated into Ca/Co alginate beads as potential chondrogenic inducing biomaterial tacking advance on the synergy between alginate matrix and Co+2 ions without employing other expensive growth factors such as TGFbs or BMPs. The expression of chondrogenic markers such as sox9, collagen type II, and versican was investigated by Real Time PCR and Western blotting analysis. The expression of hif1mRNA was investigated to check the capability of Co+2 ions to induce a chemical hypoxia. Real Time PCR and WB data reveal a different cells behaviour on chondrogenic marker expression. In conclusion, the synergic effect of alginate and Co+2 ions can represent a valid strategy for chondrogenic differentiation of stem cells

Protection against oxidant-induced apoptosis by exogenous glutathione in Leber hereditary optic neuropathy cybrids

PURPOSE. To use different paradigms of oxidative and metabolic stress in a cellular model of Leber hereditary optic neuropathy (LHON), with the aim of evaluating the efficacy of potentially therapeutic molecules for the treatment of this disease. METHODS. Cybrids bearing one of the three most common LHON pathogenic mutations (11778/ND4, 3460/ND1, 14484/ ND6) were incubated with two compounds known to induce oxidative injury, tert-butyl hydroperoxide (t-BH) and rotenone. To mimic metabolic stress, cells were incubated in a glucosefree medium containing galactose. Cell viability was determined using the MTT assay. To identify the apoptotic type of cell death, nuclear morphology was examined after cell loading with Hoechst. Cellular glutathione (GSH), and oxidized glutathione (GSSG) levels were measured enzymatically. RESULTS. Incubation with t-BH caused apoptotic cell death of control and LHON cybrids, whereas only LHON cybrids were damaged by rotenone concentrations up to 2.5 M. Both types of stress caused a marked imbalance in the glutathione levels, but an increase in the GSSG/GSHϩGSSG ratio was detected only after rotenone treatment. The efficacy of several antioxidant and antiapoptotic compounds was then assessed in cells exposed to these two oxidative paradigms. Only exogenous GSH remarkably protected the t-BH-and rotenone-treated cybrids from cell death. In contrast, GSH was unable to increase the viability of cybrids exposed to metabolic stress. CONCLUSIONS. These results suggest that GSH is an effective antioxidant compound to be tested as a potential treatment for LHON. (Invest Ophthalmol Vis Sci. 2008;49:671-676

The Background of Mitochondrial DNA Haplogroup J Increases the Sensitivity of Leber's Hereditary Optic Neuropathy Cells to 2,5-Hexanedione Toxicity

Leber's hereditary optic neuropathy (LHON) is a maternally inherited blinding disease due to mitochondrial DNA (mtDNA) point mutations in complex I subunit genes, whose incomplete penetrance has been attributed to both genetic and environmental factors. Indeed, the mtDNA background defined as haplogroup J is known to increase the penetrance of the 11778/ND4 and 14484/ND6 mutations. Recently it was also documented that the professional exposure to n-hexane might act as an exogenous trigger for LHON. Therefore, we here investigate the effect of the n-hexane neurotoxic metabolite 2,5-hexanedione (2,5-HD) on cell viability and mitochondrial function of different cell models (cybrids and fibroblasts) carrying the LHON mutations on different mtDNA haplogroups. The viability of control and LHON cybrids and fibroblasts, whose mtDNAs were completely sequenced, was assessed using the MTT assay. Mitochondrial ATP synthesis rate driven by complex I substrates was determined with the luciferine/luciferase method. Incubation with 2,5-HD caused the maximal loss of viability in control and LHON cells. The toxic effect of this compound was similar in control cells irrespective of the mtDNA background. On the contrary, sensitivity to 2,5-HD induced cell death was greatly increased in LHON cells carrying the 11778/ND4 or the 14484/ND6 mutation on haplogroup J, whereas the 11778/ND4 mutation in association with haplogroups U and H significantly improved cell survival. The 11778/ND4 mutation on haplogroup U was also more resistant to inhibition of complex I dependent ATP synthesis by 2,5-HD. In conclusion, this study shows that mtDNA haplogroups modulate the response of LHON cells to 2,5-HD. In particular, haplogroup J makes cells more sensitive to its toxic effect. This is the first evidence that an mtDNA background plays a role by interacting with an environmental factor and that 2,5-HD may be a risk element for visual loss in LHON. This proof of principle has broad implications for other neurodegenerative disorders such as Parkinson's disease

Metabolomics hallmarks OPA1 variants correlating with their in-vitro phenotype and predicting clinical severity

Interpretation of variants of uncertain significance is an actual major challenge. We addressed this question on a set of OPA1 missense variants responsible for variable severity of neurological impairments. We used targeted metabolomics to explore the different signatures of OPA1 variants expressed in Opa1 deleted mouse embryonic fibroblasts (Opa1 12/ 12 MEFs), grown under selective conditions. Multivariate analyses of data discriminated Opa1+/+ from Opa1 12/ 12 MEFs metabolic signatures and classified OPA1 variants according to their in-vitro severity. Indeed, the mild p.I382M hypomorphic variant was segregating close to the wild-type allele, while the most severe p.R445H variant was close to Opa1 12/ 12 MEFs, and the p.D603H and p.G439V alleles, responsible for isolated and syndromic presentations respectively, were intermediary between the p.I382M and the p.R445H variants. The most discriminant metabolic features were hydroxyproline, the spermine/spermidine ratio, amino acid pool and several phospholipids, emphasizing proteostasis, endoplasmic reticulum stress and phospholipid remodeling as the main mechanisms ranking OPA1 allele impacts on metabolism. These results demonstrate the high resolving power of metabolomics in hierarchizing OPA1 missense mutations by their in-vitro severity, fitting clinical expressivity. This suggests that our methodological approach can be used to discriminate the pathological significance of variants in genes responsible for other rare metabolic diseases and may be instrumental to select possible compounds eligible for supplementation treatment

Deciphering OPA1 mutations pathogenicity by combined analysis of human, mouse and yeast cell models

OPA1 is the major gene responsible for Dominant Optic Atrophy (DOA) and the syndromic form DOA “plus”. Over 370 OPA1 mutations have been identified so far, although their pathogenicity is not always clear. We have analyzed one novel and a set of known OPA1 mutations to investigate their impact on protein functions in primary skin fibroblasts and in two “ad hoc” generated cell systems: the MGM1/OPA1 chimera yeast model and the Opa1−/− MEFs model expressing the mutated human OPA1 isoform 1. The yeast model allowed us to confirm the deleterious effects of these mutations and to gain information on their dominance/recessivity. The MEFs model enhanced the phenotypic alteration caused by mutations, nicely correlating with the clinical severity observed in patients, and suggested that the DOA “plus” phenotype could be induced by the combinatorial effect of mitochondrial network fragmentation with variable degrees of mtDNA depletion. Overall, the two models proved to be valuable tools to functionally assess and define the deleterious mechanism and the pathogenicity of novel OPA1 mutations, and useful to testing new therapeutic interventions

La imagen y la narrativa como herramientas para el abordaje psicosocial en escenarios de violencia. Ciudades Bogotá, Colombia y Riobamba, Ecuador

La violencia en Colombia ha sido una constante durante muchos años debido al conflicto armado entre diferentes grupos rebeldes y el estado, es por ello que las acciones psicosociales mediante el enfoque narrativo es de gran importancia para brindar herramientas valiosas a las víctimas de violencia permitiendo la descripción de realidades y su visibilidad en pro del cambio; en este documento inicialmente se aborda el caso de Nelson una historia de exilio, con emergentes psicosociales como la extorsión, secuestro y violencia, entre otros, de donde se generaron nueve preguntas de tres tipos con su justificación, estas son, circulares como ¿Qué persona de su núcleo familiar fue clave en cuanto al proceso de fortaleza y apoyo en la toma de decisiones y cambios?, reflexivas como, ¿Qué aporte positivo tuvo el exilio en su vida?, y estratégicas como, ¿Qué cambió en usted al reunirse entre pares y conectar con otras experiencias ligadas al conflicto?, las cuales ayudan al abordaje y análisis más amplio del caso, posteriormente con el caso de la masacre del Salado, vivida por sus habitantes en el año 2020, se presenta su análisis y propuesta de estrategias de acciones psicosociales en pro de la comunidad, las cuales se titulan “Expresión, aceptación y compromiso para un mejor mañana”, “Tejidos de vida” e “Imágenes que le dan voz a los que no tienen voz”; finalmente se presenta el abordaje y reflexión con respecto a los contextos de cada uno de los estudiantes por medio de un ejercicio de foto voz presentado por medio de un video noticiero. A partir de estos ejercicios fue posible ver la importancia e impacto que vivencian las víctimas afectando su salud física, psicológica y social, sin embargo, a través de diferentes tipos de herramientas de afrontamiento y resiliencia, tomado de la mano de las redes de apoyo fortalecidas por medio de acciones psicosociales se genera un cambio en sus vidas.Violence in Colombia has been a constant for many years due to the armed conflict between different rebel groups and the state, which is why psychosocial actions through the narrative approach is of great importance to provide valuable tools to victims of violence allowing the description of realities and their visibility for change; This document initially addresses the case of Nelson, a story of exile, with psychosocial emergencies such as extortion, kidnapping and violence, among others, from which nine questions of three types were generated with their justification, these are: circular questions such as: Which person in your family nucleus was key in terms of the process of strength and support in making decisions and changes? , Reflective questions such as, What positive contribution did the exile have on your life? and strategic questions such as, What changed in you when you met with your peers and connected with other experiences linked to the conflict? which help the approach and broader analysis of the case, then with the case of the Salado massacre, experienced by its inhabitants in 2020, the analysis and proposal of strategies for psychosocial actions in favor of the community are presented, which are entitled "Expression, acceptance and commitment for a better tomorrow", "Weavings of life" and "Images that give voice to those who have no voice"; Finally, the approach and reflection with respect to the contexts of each of the students is presented through a photo voice exercise summarized in a video newscast; with these exercises it was possible to see the importance and impact experienced by the victims affecting their physical, psychological and social health, however, through different types of coping and resilience tools, taken hand in hand with the support networks strengthened through psychosocial actions, a change is generated in their lives

OPA1 Isoforms in the Hierarchical Organization of Mitochondrial Functions

OPA1 is a GTPase that controls mitochondrial fusion, cristae integrity, and mtDNA maintenance. In humans, eight isoforms are expressed as combinations of long and short forms, but it is unclear whether OPA1 functions are associated with specific isoforms and/or domains. To address this, we expressed each of the eight isoforms or different constructs of isoform 1 in Opa1−/− MEFs. We observed that any isoform could restore cristae structure, mtDNA abundance, and energetic efficiency independently of mitochondrial network morphology. Long forms supported mitochondrial fusion; short forms were better able to restore energetic efficiency. The complete rescue of mitochondrial network morphology required a balance of long and short forms of at least two isoforms, as shown by combinatorial isoform silencing and co-expression experiments. Thus, multiple OPA1 isoforms are required for mitochondrial dynamics, while any single isoform can support all other functions. These findings will be useful in designing gene therapies for patients with OPA1 haploinsufficiency