19 research outputs found
Mitochondria-Ros Crosstalk in the Control of Cell Death and Aging
Reactive oxygen species (ROS) are highly reactive molecules, mainly generated inside mitochondria that can oxidize DNA, proteins, and lipids. At physiological levels, ROS function as “redox messengers” in intracellular signalling and regulation, whereas excess ROS induce cell death by promoting the intrinsic apoptotic pathway. Recent work has pointed to a further role of ROS in activation of autophagy and their importance in the regulation of aging. This review will focus on mitochondria as producers and targets of ROS and will summarize different proteins that modulate the redox state of the cell. Moreover, the involvement of ROS and mitochondria in different molecular pathways controlling lifespan will be reported, pointing out the role of ROS as a “balance of power,” directing the cell towards life or death
p66Shc Aging Protein in Control of Fibroblasts Cell Fate
Reactive oxygen species (ROS) are wieldy accepted as one of the main factors of the aging process. These highly reactive compounds modify nucleic acids, proteins and lipids and affect the functionality of mitochondria in the first case and ultimately of the cell. Any agent or genetic modification that affects ROS production and detoxification can be expected to influence longevity. On the other hand, genetic manipulations leading to increased longevity can be expected to involve cellular changes that affect ROS metabolism. The 66-kDa isoform of the growth factor adaptor Shc (p66Shc) has been recognized as a relevant factor to the oxygen radical theory of aging. The most recent data indicate that p66Shc protein regulates life span in mammals and its phosphorylation on serine 36 is important for the initiation of cell death upon oxidative stress. Moreover, there is strong evidence that apart from aging, p66Shc may be implicated in many oxidative stress-associated pathologies, such as diabetes, mitochondrial and neurodegenerative disorders and tumorigenesis. This article summarizes recent knowledge about the role of p66Shc in aging and senescence and how this protein can influence ROS production and detoxification, focusing on studies performed on skin and skin fibroblasts
Mitochondria-Associated Membranes: Composition, Molecular Mechanisms, and Physiopathological Implications
Significance:
In all cells, the endoplasmic reticulum (ER) and mitochondria are physically connected to form
junctions termed mitochondria-associated membranes ( MAMs). This subcellular compartment is under intense
investigation because it represents a ‘‘hot spot’’ for the intracellular signaling of important pathways, including
the synthesis of cholesterol and phospholipids, calcium homeostasis, and reactive oxygen species (ROS)
generation and activity.
Recent Advances:
The advanced methods currently used to study this fascinating
intracellular microdomain in detail have enabled the identification of the molecular composition of MAMs and
their involvement within different physiopathological contexts.
Critical Issues:
Here, we review the knowledge
regarding (i) MAMs composition in terms of protein composition, (ii) the relationship between MAMs and
ROS, (iii) the involvement of MAMs in cell death programs with particular emphasis within the tumor context,
(iv) the emerging role of MAMs during inflammation, and (v) the key role of MAMs alterations in selected
neurological disorders.
Future Directions:
Whether alterations in MAMs represent a response to the disease
pathogenesis or directly contribute to the disease has not yet been unequivocally established. In any case, the
signaling at the MAMs represents a promising pharmacological target for several important human diseases
Relation Between Mitochondrial Membrane Potential and ROS Formation
Mitochondria are considered the main source of reactive oxygen species (ROS) in the cell. For this reason they have been recognized as a source of various pathological conditions as well as aging. Chronic increase in the rate of ROS production is responsible for the accumulation of ROS-associated damages in DNA, proteins, and lipids and may result in progressive cell dysfunctions and, in a consequence, apoptosis, increasing the overall probability of an organism's pathological conditions. The superoxide anion is the main undesired by-product of mitochondrial oxidative phosphorylation. Its production is triggered by a leak of electrons from the mitochondrial respiratory chain and the reaction of these electrons with O-2. Superoxide dismutase (MnSOD, SOD2) from the mitochondrial matrix, as well as superoxide dismutase (Cu/ ZnSOD, SOD1) present in small amounts in the mitochondrial intramembrane space, converts superoxide anion to hydrogen peroxide, which can be then converted by catalase to harmless H2O.In the chapter we describe a relation between mitochondrial membrane potential and the rate of ROS formation. We present different methods applicable for isolated mitochondria or intact cells. We also present experiments demonstrating that a magnitude and a direction (increase or decrease) of a change in mitochondrial ROS production depend on the metabolic state of this organelle
Oncogenic and oncosuppressive signal transduction at mitochondria-associated endoplasmic reticulum membranes
The different mechanisms employed by proto-oncogenes
and tumor suppressors to regulate cell death pathways are
strictly linked to their localization. In addition to the canonical
control of apoptosis at a transcriptional/nuclear level,
intracellular zones are emerging as pivotal sites for the
activities of several proapoptotic and antiapoptotic factors.
Here, we review the function of the endoplasmic reticulum-
mitochondria interface as a primary platform for decoding
danger signals as well as a structural accommodation for
several regulator or effector proteins
Recovering Mitochondrial Function in Patients’ Fibroblasts
Despite the fact that majority of studies done using different compounds
with antioxidant properties showing pivotal effect on oxidative phosphorylation or
glycolytic ATP production, it is still difficult to discuss efficient therapeutic solutions
for patients affected by mitochondrial diseases or mitochondrial dysfunction-associated
disorders. Since most of the mitochondrial disorders are manifested in
tissues or organs that demand high-energy, many experimental studies have
described that the pivotal effect of the tested compounds comes from the use of the
skin fibroblasts from patients. In this chapter, we have gathered information about
these studies and describe the effect of such treatment on mitochondrial function
and the attenuation of oxidative stress in patients’ fibroblasts