7-methyl-5-(1-((3-(trifluoromethyl)phenyl)acetyl)-2-3-dihydro-1h-indol-5-yl)-7h-pyrrolo(2-3-d)pyrimidin-4-amine and Neurodegenerative-Diseases

Perturbed neuronal proteostasis is a salient feature shared by both aging and protein misfolding disorders. The proteostasis network controls the health of the proteome by integrating pathways involved in protein synthesis, folding, trafficking, secretion, and their degradation. A reduction in the buffering capacity of the proteostasis network during aging may increase the risk to undergo neurodegeneration by enhancing the accumulation of misfolded proteins. As almost one-third of the proteome is synthetized at the endoplasmic reticulum (ER), maintenance of its proper function is fundamental to sustain neuronal function. In fact, ER stress is a common feature of most neurodegenerative diseases. The unfolded protein response (UPR) operates as central player to maintain ER homeostasis or the induction of cell death of chronically damaged cells. Here, we discuss recent evidence placing ER stress as a driver of brain aging, and the emerging impact of neuronal UPR in controlling global proteostasis at the whole organismal level. Finally, we discuss possible therapeutic interventions to improve proteostasis and prevent pathological brain aging.

Topics: Adenine; Aging; Animals; Brain; Caenorhabditis elegans; Drosophila melanogaster; Endoplasmic Reticulum Stress; Guanabenz; Humans; Indoles; Neurodegenerative Diseases; Neurons; Protective Agents; Proteome; Proteostasis; Proteostasis Deficiencies; Saccharomyces cerevisiae; Unfolded Protein Response

Neurodegenerative diseases are characterized by the aggregation of misfolded proteins in the brain. Among these disorders are the prion diseases, which are transmissible, and in which the misfolded proteins ("prions") are also the infectious agent. Increasingly, it appears that misfolded proteins in Alzheimer and Parkinson diseases and the tauopathies also propagate in a "prion-like" manner. However, the association between prion formation, spread, and neurotoxicity is not clear. Recently, we showed that in prion disease, protein misfolding leads to neurodegeneration through dysregulation of generic proteostatic mechanisms, specifically, the unfolded protein response. Genetic and pharmacological manipulation of the unfolded protein response was neuroprotective despite continuing prion replication, hence dissociating this from neurotoxicity. The data have clear implications for treatment across the spectrum of these disorders, targeting pathogenic processes downstream of protein misfolding.

Topics: Adenine; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; eIF-2 Kinase; Humans; Indoles; Neurodegenerative Diseases; Parkinson Disease; Prion Diseases; Prions; Protein Conformation; Protein Kinase Inhibitors; tau Proteins; Tauopathies; Unfolded Protein Response

Topics: Adenine; Animals; Apoptosis; Atrophy; Cell Line, Tumor; eIF-2 Kinase; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; G(M2) Ganglioside; Gangliosidoses, GM2; Indoles; Mice; Neurites; Neurodegenerative Diseases; Neurons; Signal Transduction; Transcription Factor CHOP; Unfolded Protein Response

Parkinson's disease (PD) is the second most common neurodegenerative disorder, leading to the progressive decline of motor control due to the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Accumulating evidence suggest that altered proteostasis is a salient feature of PD, highlighting perturbations to the endoplasmic reticulum (ER), the main compartment involved in protein folding and secretion. PERK is a central ER stress sensor that enforces adaptive programs to recover homeostasis through a block of protein translation and the induction of the transcription factor ATF4. In addition, chronic PERK signaling results in apoptosis induction and neuronal dysfunction due to the repression in the translation of synaptic proteins. Here we confirmed the activation of PERK signaling in postmortem brain tissue derived from PD patients and three different rodent models of the disease. Pharmacological targeting of PERK by the oral administration of GSK2606414 demonstrated efficient inhibition of the pathway in the SNpc after experimental ER stress stimulation. GSK2606414 protected nigral-dopaminergic neurons against a PD-inducing neurotoxin, improving motor performance. The neuroprotective effects of PERK inhibition were accompanied by an increase in dopamine levels and the expression of synaptic proteins. However, GSK2606414 treated animals developed secondary effects possibly related to pancreatic toxicity. This study suggests that strategies to attenuate ER stress levels may be effective to reduce neurodegeneration in PD.

Topics: Adenine; Animals; Disease Models, Animal; eIF-2 Kinase; Female; Humans; Indoles; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Oxidopamine; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Signal Transduction