8 research outputs found
The intrinsic chaperone network of Arabidopsis stem cells confers protection against proteotoxic stress
The biological purpose of plant stem cells is to maintain themselves while providing new pools of differentiated cells that form organs and rejuvenate or replace damaged tissues. Protein homeostasis or proteostasis is required for cell function and viability. However, the link between proteostasis and plant stem cell identity remains unknown. In contrast to their differentiated counterparts, we find that root stem cells can prevent the accumulation of aggregated proteins even under proteotoxic stress conditions such as heat stress or proteasome inhibition. Notably, root stem cells exhibit enhanced expression of distinct chaperones that maintain proteome integrity. Particularly, intrinsic high levels of the T-complex protein-1 ring complex/chaperonin containing TCP1 (TRiC/CCT) complex determine stem cell maintenance and their remarkable ability to suppress protein aggregation. Overexpression of CCT8, a key activator of TRiC/CCT assembly, is sufficient to ameliorate protein aggregation in differentiated cells and confer resistance to proteotoxic stress in plants. Taken together, our results indicate that enhanced proteostasis mechanisms in stem cells could be an important requirement for plants to persist under extreme environmental conditions and reach extreme long ages. Thus, proteostasis of stem cells can provide insights to design and breed plants tolerant to environmental challenges caused by the climate change
Dietary protein restriction decreases oxidative protein damage, peroxidizability index, and mitochondrial complex I content in rat liver
Caloric restriction (CR) decreases oxidative damage, which contributes to the slowing of aging
rate. It is not known if such decreases are due to calories themselves or specific dietary components.
In this work, the ingestion of proteins of Wistar rats was decreased by 40% below that
of controls. After 7 weeks, the liver of the protein-restricted (PR) animals showed decreases in
oxidative protein damage, degree of membrane unsaturation, and mitochondrial complex I
content. The results and previous information suggest that the decrease in the rate of aging
induced by PR can be due in part to decreases in mitochondrial reactive oxygen species
production and DNA and protein oxidative modification, increases in fatty acid components more
resistant to oxidative damage, and decreased expression of complex I, analogously to what occurs
during CR. Recent studies suggest that those benefits of PR could be caused, in turn, by the
lowered methionine intake of that dietary manipulatio
Plasma long-chain free fatty acids predict mammalian longevity
determination of their longevity. In the present work, the use of high-throughput technologies allowed us to
determine the plasma lipidomic profile of 11 mammalian species ranging in maximum longevity from 3.5 to
120 years. The non-targeted approach revealed a specie-specific lipidomic profile that accurately predicts the
animal longevity. The regression analysis between lipid species and longevity demonstrated that the longer
the longevity of a species, the lower is its plasma long-chain free fatty acid (LC-FFA) concentrations,
peroxidizability index, and lipid peroxidation-derived products content. The inverse association between longevity and LC-FFA persisted after correction for body mass and phylogenetic interdependence. These
results indicate that the lipidomic signature is an optimized feature associated with animal longevity, emerging LC-FFA as a potential biomarker of longevit
Formation of S-(carboxymethyl)-cysteine in rat liver mitochondrial proteins: effects of caloric and methionine restriction
Maillard reaction contributes to the chemical
modification and cross-linking of proteins. This process
plays a significant role in the aging process and determination
of animal longevity. Oxidative conditions promote
the Maillard reaction. Mitochondria are the primary site of
oxidants due to the reactive molecular species production.
Mitochondrial proteome cysteine residues are targets of
oxidative attack due to their specific chemistry and localization.
Their chemical, non-enzymatic modification leads
to dysfunctional proteins, which entail cellular senescence
and organismal aging. Previous studies have consistently
shown that caloric and methionine restrictions, nutritional
interventions that increase longevity, decrease the rate of
mitochondrial oxidant production and the physiological
steady-state levels of markers of oxidative damage to
macromolecules. In this scenario, we have detected
S-(carboxymethyl)-cysteine (CMC) as a new irreversible
chemical modification in mitochondrial proteins. CMC
content in mitochondrial proteins significantly correlated
with that of the lysine-derived analog Ne-(carboxymethyl)-
lysine. The concentration of CMC is, however, one order of
magnitude lower compared with CML likely due in part to
the lower content of cysteine with respect to lysine of the
mitochondrial proteome. CMC concentrations decreases in
liver mitochondrial proteins of rats subjected to 8.5 and 25 % caloric restriction, as well as in 40 and 80 %
methionine restriction. This is associated with a concomitant
and significant increase in the protein content of
sulfhydryl groups. Data presented here evidence that CMC,
a marker of Cys-AGE formation, could be candidate as a
biomarker of mitochondrial damage during aging