Role of Oxidative Stress, ER Stress and Ubiquitin Proteasome System in Neurodegeneration

The role of oxidative stress in neurodegenerative diseases and potential antioxidant therapies

Objectives

The central nervous system (CNS) is essential for homeostasis and controls the physiological functions of the body. However, the biochemical characteristics of the CNS make it especially vulnerable to oxidative damage (OS). This phenomenon compromises correct CNS functioning, leading to neurodegeneration and neuronal death.

Contents

OS plays a crucial role in the physiopathology of neurodegenerative diseases. It is involved in multiple mechanisms of nucleic acid, protein, and lipid oxidation, thereby contributing to progressive brain damage. These mechanisms include mitochondrial dysfunction; excessive production of reactive oxygen and nitrogen species; deficiency of antioxidant defenses; protein oligomerization; cytokine production and inflammatory response; blood-brain barrier abnormalities; and proteasome dysfunction. All these dysfunctions are involved in the pathogenesis of neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, Huntington's disease, or amyotrophic lateral sclerosis.

Summary and outlook

A curative treatment is currently not available. Research is focused on the search for therapies that reduce oxidative damage and delay disease progression. In the recent years, researchers have focused their attention on the effects of antioxidant therapies.

Role of Polyphenols on Gut Microbiota and the Ubiquitin-Proteasome System in Neurodegenerative Diseases

Today, neurodegenerative diseases have become a remarkable public health challenge due to their direct relation with aging. Accordingly, understanding the molecular and cellular mechanisms occurring in the pathogenesis of them is essential. Both protein aggregations as a result of the ubiquitin-proteasome system (UPS) inefficiency and gut microbiota alternation are the main pathogenic hallmarks. Polyphenols upregulating this system may decrease the developing rate of neurodegenerative diseases. Most of the dietary intake of polyphenols is converted into other microbial metabolites, which have completely different biological properties from the original polyphenols and should be thoroughly investigated. Herein, several prevalent neurodegenerative diseases are pinpointed to explain the role of gut microbiota alternations and the role of molecular changes, especially UPS down-regulation in their pathogenesis. Some of the most important polyphenols found in our diet are explained along with their microbial metabolites in the body.