Many researchers have reported that oxidative damage to mitochondrial DNA (mtDNA) is increased in several age-related disorders. Damage to mitochondrial constituents and mtDNA can generate additional mitochondrial dysfunction that may result in greater reactive oxygen species production, triggering a circular chain of events. However, the mechanisms underlying this vicious cycle have yet to be fully investigated. In this review, we summarize the relationship of oxidative stress-induced mitochondrial dysfunction with mtDNA mutation in neurodegenerative disorders.
Animals ; DNA, Mitochondrial/*genetics ; Humans ; Mitochondria/drug effects/genetics/metabolism ; Molecular Targeted Therapy ; *Mutation ; Neurodegenerative Diseases/drug therapy/*genetics/metabolism ; Reactive Oxygen Species/metabolism

Mammalian cells remove misfolded proteins using various proteolytic systems, including the ubiquitin (Ub)-proteasome system (UPS), chaperone mediated autophagy (CMA) and macroautophagy. The majority of misfolded proteins are degraded by the UPS, in which Ub-conjugated substrates are deubiquitinated, unfolded and cleaved into small peptides when passing through the narrow chamber of the proteasome. The substrates that expose a specific degradation signal, the KFERQ sequence motif, can be delivered to and degraded in lysosomes via the CMA. Aggregation-prone substrates resistant to both the UPS and the CMA can be degraded by macroautophagy, in which cargoes are segregated into autophagosomes before degradation by lysosomal hydrolases. Although most misfolded and aggregated proteins in the human proteome can be degraded by cellular protein quality control, some native and mutant proteins prone to aggregation into beta-sheet-enriched oligomers are resistant to all known proteolytic pathways and can thus grow into inclusion bodies or extracellular plaques. The accumulation of protease-resistant misfolded and aggregated proteins is a common mechanism underlying protein misfolding disorders, including neurodegenerative diseases such as Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), prion diseases and Amyotrophic Lateral Sclerosis (ALS). In this review, we provide an overview of the proteolytic pathways in neurons, with an emphasis on the UPS, CMA and macroautophagy, and discuss the role of protein quality control in the degradation of pathogenic proteins in neurodegenerative diseases. Additionally, we examine existing putative therapeutic strategies to efficiently remove cytotoxic proteins from degenerating neurons.
Alzheimer Disease/drug therapy/metabolism ; Amyloid beta-Peptides/metabolism ; Amyotrophic Lateral Sclerosis/drug therapy/metabolism ; Animals ; Autophagy/drug effects ; DNA-Binding Proteins/metabolism ; Humans ; Huntington Disease/drug therapy/genetics/metabolism ; Lysosomes/metabolism ; Molecular Targeted Therapy ; Mutation ; Nerve Tissue Proteins/genetics/metabolism ; Neurodegenerative Diseases/drug therapy/*metabolism ; Parkinson Disease/drug therapy/metabolism ; PrPSc Proteins/metabolism ; Prion Diseases/drug therapy/metabolism ; Proteasome Endopeptidase Complex/metabolism ; Proteolysis ; Proteostasis Deficiencies/metabolism ; Superoxide Dismutase/metabolism ; Ubiquitin/metabolism ; alpha-Synuclein/metabolism ; tau Proteins/metabolism

Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme involved in the base excision repair (BER) pathway, which repairs oxidative base damage caused by endogenous and exogenous agents. APE1 acts as a reductive activator of many transcription factors (TFs) and has also been named redox effector factor 1, Ref-1. For example, APE1 activates activator protein-1, nuclear factor kappa B, hypoxia-inducible factor 1alpha, paired box gene 8, signal transducer activator of transcription 3 and p53, which are involved in apoptosis, inflammation, angiogenesis and survival pathways. APE1/Ref-1 maintains cellular homeostasis (redox) via the activation of TFs that regulate various physiological processes and that crosstalk with redox balancing agents (for example, thioredoxin, catalase and superoxide dismutase) by controlling levels of reactive oxygen and nitrogen species. The efficiency of APE1/Ref-1's function(s) depends on pairwise interaction with participant protein(s), the functions regulated by APE1/Ref-1 include the BER pathway, TFs, energy metabolism, cytoskeletal elements and stress-dependent responses. Thus, APE1/Ref-1 acts as a 'hub-protein' that controls pathways that are important for cell survival. In this review, we will discuss APE1/Ref-1's versatile nature in various human etiologies, including neurodegeneration, cancer, cardiovascular and other diseases that have been linked with alterations in the expression, subcellular localization and activities of APE/Ref-1. APE1/Ref-1 can be targeted for therapeutic intervention using natural plant products that modulate the expression and functions of APE1/Ref-1. In addition, studies focusing on translational applications based on APE1/Ref-1-mediated therapeutic interventions are discussed.
Animals ; DNA Damage ; DNA Repair ; DNA-(Apurinic or Apyrimidinic Site) Lyase/analysis/genetics/*metabolism ; Humans ; *Molecular Targeted Therapy/methods ; Neoplasms/*drug therapy/genetics/*metabolism ; Neurodegenerative Diseases/*drug therapy/genetics/*metabolism ; Oxidative Stress ; Phytochemicals/pharmacology/*therapeutic use ; Polymorphism, Genetic ; Protein Interaction Maps

Hematopoietic stem cell transplantation (HSCT) is the first field where human stem cell therapy was successful. Flooding interest on human stem cell therapy to cure previously incurable diseases is largely indebted to HSCT success. Allogeneic HSCT has been an important modality to cure various diseases including hematologic malignancies, various non-malignant hematologic diseases, primary immunodeficiency diseases, and inborn errors of metabolism, while autologous HSCT is generally performed to rescue bone marrow aplasia following high-dose chemotherapy for solid tumors or multiple myeloma. Recently, HSCs are also spotlighted in the field of regenerative medicine for the amelioration of symptoms caused by neurodegenerative diseases, heart diseases, and others. Although the demand for HSCs has been growing, their supply often fails to meet the demand of the patients needing transplant due to a lack of histocompatible donors or a limited cell number. This review focuses on the generation and large-scale expansion of HSCs, which might overcome current limitations in the application of HSCs for clinical use. Furthermore, current proof of concept to replenish hematological homeostasis from non-hematological origin will be covered.
Bone Marrow ; Cell Count ; Drug Therapy ; Heart Diseases ; Hematologic Diseases ; Hematologic Neoplasms ; Hematopoietic Stem Cell Transplantation ; Hematopoietic Stem Cells* ; Homeostasis ; Humans ; Metabolism, Inborn Errors ; Multiple Myeloma ; Neurodegenerative Diseases ; Regenerative Medicine ; Stem Cells ; Tissue Donors

Many major neurodegenerative diseases are associated with proteins misfolding and aggregation, which are also called "neurodegenerative conformational disease". The interaction of gene mutation and environmental factors are probably primary events resulting in oligomer and aggregate formations of proteins. Moreover, the dysfunctions of protein control systems, i.e. the ubiquitin-proteasome system and autophagy-lysosomal system, also contribute to the neurodegenerative process. The present review mainly summarizes protein misfolding and aggregation in the development of neurodegenerative conformational disease and the underling mechanisms, as well as upregulation of heatshock proteins as a promising treatment method for this kind of disease.
Alzheimer Disease ; drug therapy ; genetics ; metabolism ; pathology ; Animals ; Annona ; chemistry ; Autophagy ; Benzeneacetamides ; isolation & purification ; therapeutic use ; Heat-Shock Proteins ; metabolism ; physiology ; Humans ; Mutation ; Neurodegenerative Diseases ; drug therapy ; genetics ; metabolism ; pathology ; Parkinson Disease ; drug therapy ; genetics ; metabolism ; pathology ; Phenols ; isolation & purification ; therapeutic use ; Plants, Medicinal ; chemistry ; Proteasome Endopeptidase Complex ; metabolism ; Protein Folding ; Ubiquitin ; metabolism

Human embryonic stem cells (hESCs) are pluripotent cells that have the ability of unlimited self-renewal and can be differentiated into different cell lineages, including neural stem (NS) cells. Diverse regulatory signaling pathways of neural stem cells differentiation have been discovered, and this will be of great benefit to uncover the mechanisms of neuronal differentiation in vivo and in vitro. However, the limitations of hESCs resource along with the religious and ethical concerns impede the progress of ESCs application. Therefore, the induced pluripotent stem cells (iPSCs) via somatic cell reprogramming have opened up another new territory for regenerative medicine. iPSCs now can be derived from a number of lineages of cells, and are able to differentiate into certain cell types, including neurons. Patient-specifi c iPSCs are being used in human neurodegenerative disease modeling and drug screening. Furthermore, with the development of somatic direct reprogramming or lineage reprogramming technique, a more effective approach for regenerative medicine could become a complement for iPSCs.
Cell Differentiation ; Cell Lineage ; Cell Transdifferentiation ; Cellular Reprogramming ; drug effects ; Embryonic Stem Cells ; cytology ; Humans ; Induced Pluripotent Stem Cells ; cytology ; transplantation ; Neural Stem Cells ; cytology ; transplantation ; Neurodegenerative Diseases ; therapy ; Regenerative Medicine ; Transcription Factors ; genetics ; metabolism

Extracts of Chinese herb Tripterygium wilfordii Hook. f. (TWHF) have been found to have potent anti-inflammatory and immunosuppressive functions and widely used in China for treatment of rheumatoid arthritis. Also they have been considered to be the potential drugs in the treatment of tumor and acute graft rejections. With the progress of neuroimmunological research on neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson disease (PD) and multiple sclerosis (MS), the neuroprotective strategies to rescue neurons from immunological injury are currently being explored. Recently, studies have indicated that extracts of TWHF such as triptolide, tripchlorolide and (5R)-5-hydroxytriptolide are able to attenuate progression of these neuroimmunologic disorders in vitro and in vivo. Accumulating evidence has shown that they can promote neuronal survival and neurite growth and facilitate functional recovery of brain injury by invoking distinct mechanisms that are related to their neuroprotective roles as inhibitor of neuroinflammatory toxicity of activated-microglia, antioxidants, calcium channel blockers, neurotrophic actions, modulating T cell functions, inhibitor of transcriptional activation of NF-kappaB on genes and signaling. Significant pharmaceutical strategies against neuroimmunologic disorders will hopefully be discovered by understanding the valuable components of TWHF.
Animals ; Anti-Inflammatory Agents ; pharmacology ; Antioxidants ; pharmacology ; Diterpenes ; isolation & purification ; pharmacology ; therapeutic use ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; therapeutic use ; Epoxy Compounds ; isolation & purification ; pharmacology ; therapeutic use ; Humans ; NF-kappa B ; metabolism ; Neurodegenerative Diseases ; drug therapy ; prevention & control ; Phenanthrenes ; isolation & purification ; pharmacology ; therapeutic use ; Structure-Activity Relationship ; Tripterygium ; chemistry