Combined transcriptomics and proteomics unveil the impact of vitamin C in modulating specific protein abundance in the mouse liver.

BACKGROUND: Vitamin C (ascorbate) is a water-soluble antioxidant and an important cofactor for various biosynthetic and regulatory enzymes. Mice can synthesize vitamin C thanks to the key enzyme gulonolactone oxidase (Gulo) unlike humans. In the current investigation, we used Gulo-/- mice, which cannot synthesize their own ascorbate to determine the impact of this vitamin on both the transcriptomics and proteomics profiles in the whole liver. The study included Gulo-/- mouse groups treated with either sub-optimal or optimal ascorbate concentrations in drinking water. Liver tissues of females and males were collected at the age of four months and divided for transcriptomics and proteomics analysis. Immunoblotting, quantitative RT-PCR, and polysome profiling experiments were also conducted to complement our combined omics studies. RESULTS: Principal component analyses revealed distinctive differences in the mRNA and protein profiles as a function of sex between all the mouse cohorts. Despite such sexual dimorphism, Spearman analyses of transcriptomics data from females and males revealed correlations of hepatic ascorbate levels with transcripts encoding a wide array of biological processes involved in glucose and lipid metabolisms as well as in the acute-phase immune response. Moreover, integration of the proteomics data showed that ascorbate modulates the abundance of various enzymes involved in lipid, xenobiotic, organic acid, acetyl-CoA, and steroid metabolism mainly at the transcriptional level, especially in females. However, several proteins of the mitochondrial complex III significantly correlated with ascorbate concentrations in both males and females unlike their corresponding transcripts. Finally, poly(ribo)some profiling did not reveal significant enrichment difference for these mitochondrial complex III mRNAs between Gulo-/- mice treated with sub-optimal and optimal ascorbate levels. CONCLUSIONS: Thus, the abundance of several subunits of the mitochondrial complex III are regulated by ascorbate at the post-transcriptional levels. Our extensive omics analyses provide a novel resource of altered gene expression patterns at the transcriptional and post-transcriptional levels under ascorbate deficiency.

Combined transcriptomics and proteomics unveil the impact of vitamin C in modulating specific protein abundance in the mouse liver

Background Vitamin C (ascorbate) is a water-soluble antioxidant and an important cofactor for various biosynthetic and regulatory enzymes. Mice can synthesize vitamin C thanks to the key enzyme gulonolactone oxidase (Gulo) unlike humans. In the current investigation, we used Gulo-/- mice, which cannot synthesize their own ascorbate to determine the impact of this vitamin on both the transcriptomics and proteomics profiles in the whole liver. The study included Gulo-/- mouse groups treated with either sub-optimal or optimal ascorbate concentrations in drinking water. Liver tissues of females and males were collected at the age of four months and divided for transcriptomics and proteomics analysis. Immunoblotting, quantitative RT-PCR, and polysome profiling experiments were also conducted to complement our combined omics studies. Results Principal component analyses revealed distinctive differences in the mRNA and protein profiles as a function of sex between all the mouse cohorts. Despite such sexual dimorphism, Spearman analyses of transcriptomics data from females and males revealed correlations of hepatic ascorbate levels with transcripts encoding a wide array of biological processes involved in glucose and lipid metabolisms as well as in the acute-phase immune response. Moreover, integration of the proteomics data showed that ascorbate modulates the abundance of various enzymes involved in lipid, xenobiotic, organic acid, acetyl-CoA, and steroid metabolism mainly at the transcriptional level, especially in females. However, several proteins of the mitochondrial complex III significantly correlated with ascorbate concentrations in both males and females unlike their corresponding transcripts. Finally, poly(ribo)some profiling did not reveal significant enrichment difference for these mitochondrial complex III mRNAs between Gulo-/- mice treated with sub-optimal and optimal ascorbate levels. Conclusions Thus, the abundance of several subunits of the mitochondrial complex III are regulated by ascorbate at the post-transcriptional levels. Our extensive omics analyses provide a novel resource of altered gene expression patterns at the transcriptional and post-transcriptional levels under ascorbate deficiency.

ROS scavenging of SOD/CAT mimics probed by EPR and reduction of lipid peroxidation in S. cerevisiae and mouse liver, under severe hydroxyl radical stress condition.

The interaction between CuII, FeIII and MnII complexes, derived from the ligands 1-[bis(pyridine-2-ylmethyl)amino]-3-chloropropan-2-ol (hpclnol) and bis(pyridine-2-ylmethyl)amine (bpma), and the free radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) and reactive oxygen species (ROS), was investigated by colorimetric and EPR (Electron Paramagnetic Resonance) techniques. A comparison between these results and those reported to [Mn(salen)Cl] or EUK-8 was also addressed. EPR studies allowed us the identification of intermediates species such as superoxide­copper(I) and superoxide­copper(II), a mixed-valence FeIIIFeII species and a 16-line feature attributed to MnIII-oxo-MnIV species. The biomarker malondialdehyde (MDA) was determined by TBARS assay in S. cerevisiae cells, and the determination of the IC50 indicate that the antioxidant activity shown dependence on the metal center (CuII ≈ FeIII > MnII ≈ [Mn(salen)Cl]. The lipid peroxidation attenuation was also investigated in liver homogenates obtained from Swiss mice and the IC50 values were in the nanomolar concentrations. We demonstrated here that all the complexes interact with the free radical DPPH and with ROS (H2O2, O2•- and hydroxyl radical), enhancing the cellular protection against oxidative stress generated by hydroxyl radical, employing two experimental model systems, S. cerevisiae (in vivo) and mouse liver (ex vivo).

Histopathological effects of boron on mouse liver / Efectos histopatológicos del boro en hígado de ratón

Boron is a non-metal element, commonly found in Nature as borates in sedimentary rocks, charcoal, oceans and soils. In Chile, it is found in high concentrations in the drinkable water of the XV region, in Arica city, in concentrations that exceed the WHO normative. The present work evaluates the effect of boron at a dose of 12 mg/L of water (equivalent to 0.0686 g of boric acid) given orally for 8,42 and 49 days to 3 experimental groups of 10 mice each. Liver sections were stained with PAS-hematoxyline (to evaluate glycogen), Mallory (to identify collagen fibers) and Picrosirius red with polarizing light to classify collagen fibers. Results indicate that boron evokes diverse effects in liver. Binucleated cells were evaluated and counted and results were analyzed with the non-parametric Mann-Whitney test. Control group (8-day-old mice) had 22.9 binucleated cells per 200 hepatocytes and the boron exposed group (8-day-old mice) showed 28.5 (p>0.05). Therefore, there are not significant differences among these groups. In the 126-day-old mice, the control group had 43.9 binucleated cells per 200 hepatocytes and the boron exposed group showed 76.0, a statistically significant difference (p<0.01). Regarding PAS staining, intensity was classified as low, moderate or intense and analysis was done with the Chi-Square test. All control and experimental groups differed with slight statistical significance (p=0.05). With regard to Mallory staining, intensity was examined in two specific areas: portal triads (PTr) and central veins (CV). There were significant augments in both PTr and CV results after experimental and control groups comparison. Picrosirius red staining examined in polarized microscopy revealed that collagen III was predominant in boron treated mice, denoting collagenolysis of collagen I as toxical effect of boron. In conclusion, boron alters glycogen distribution and collagen quality and deposition in the two examined areas, whereas...

El boro es un elemento metaloide que se encuentra presente en la naturaleza en forma de boratos en rocas sedimentarias, carbón, océanos y algunos suelos. En nuestro país se encuentra en altas concentraciones en el agua potable de la XV región, en la ciudad de Arica, superando el límite máximo recomendado por la OMS. Se evaluó el efecto del boro, en una dosis de 12 mg/L de agua (equivalente 0,0686 G de ac. bórico) administrado por vía oral durante 8, 42 y 49 días a 3 grupos experimentales (10 animales cada uno). Cortes de hígado se tiñieron con Hematoxilina-eosina (células binucleadas), PAS hematoxilina (glicógeno hepático), Mallory y Rojo Picrosirius (fibras de colágeno). El boro produce diversos efectos en el hígado. Para el estudio de células binucleadas se utilizó el test no paramétrico de Mann-Whitney. El grupo C1 tuvo 22,9 células binucleadas cada 200 hepatocitos, en cambio E1 mostró 28,5 (p> 0,05) el análisis no arrojó una diferencia estadísticamente significativa entre ambos grupos. Grupo C2-3 mostró 43,9 células binucleadas cada 200 hepatocitos, por su parte E2-3 76 (p menor a 0,01) en este caso sí existe diferencia significa entre ambos grupos. La tinción de PAS fue clasificada como leve, moderada e intensa y su análisis realizado mediante Chi- Cuadrado. Todos los grupos controles y experimentales arrojaron diferencias significativas (p<0,01). La tinción de Mallory fue examinada en: triadas portales (TrP) y venas centrales (VC). En ambas hubo incremento significativo. La tinción con Rojo Picrosirius analizada por microscopía de polarización, demostró que el colágeno III predomina en los animales tratados con boro, indicando colagenolisis de colágeno I como efecto tóxico del boro. En conclusión, el boro altera la distribución del glicógeno, la calidad del colágeno y el depósito de ambos en las dos áreas examinadas, en tanto que la cantidad de células binucleadas se comportan de forma distinta en los animales jóvenes respecto a los adultos.