A chemical genomics-aggrephagy integrated method studying functional analysis of autophagy inducers

Abstract

Macroautophagy/autophagy plays a critical role in the pathogenesis of various human diseases including neurodegenerative disorders such as Parkinson disease (PD) and Huntington disease (HD). Chemical autophagy inducers are expected to serve as disease-modifying agents by eliminating cytotoxic/ damaged proteins. Although many autophagy inducers have been identified, their precise molecular mechanisms are not fully understood because of the complicated crosstalk among signaling pathways. To address this issue, we performed several chemical genomic analyses enabling us to comprehend the dominancy among the autophagy-associated pathways followed by an aggresome-clearance assay. In a first step, more than 400 target-established small molecules were assessed for their ability to activate autophagic flux in neuronal PC12D cells, and we identified 39 compounds as autophagy inducers. We then profiled the autophagy inducers by testing their effect on the induction of autophagy by 200 wellestablished signal transduction modulators. Our principal component analysis (PCA) and clustering analysis using a dataset of "autophagy profiles" revealed that two Food and Drug Administration (FDA)approved drugs, memantine and clemastine, activate endoplasmic reticulum (ER) stress responses, which could lead to autophagy induction. We also confirmed that SMK-17, a recently identified autophagy inducer, induced autophagy via the PRKC/PKC-TFEB pathway, as had been predicted from PCA. Finally, we showed that almost all of the autophagy inducers tested in this present work significantly enhanced the clearance of the protein aggregates observed in cellular models of PD and HD. These results, with the combined approach, suggested that autophagy-activating small molecules may improve proteinopathies by eliminating nonfunctional protein aggregates.

The Role of Autophagy in Anti-Cancer and Health Promoting Effects of Cordycepin

“…These results show the deficits of the autophagy system in HD and suggest that therapy targeting autophagy is a potential direction for this disease. Indeed, several drugs, such as minoxidil, clonidine, phenoxazine, everolimus, memantine, and clemastine, have been observed in different HD models to induce the autophagy system and have been shown to improve or alleviate HD phenotypes [ 116 , 117 , 118 , 119 ]. Taking these results for AD, PD, and HD together, autophagy not only plays an important role in cleaning disease-causing proteins inside cells but also serves as a potential direction to treat neurodegenerative diseases.…”

Prionoids in amyotrophic lateral sclerosis

“… 188 Clinical trials are underway to evaluate a series of drugs acting on proteostasis, such as arimoclomol, 189 fasudil 190 and memantine. 191 …”

Identification of an ERN1 target site within EGFP mRNA

“…Proteostatic stress, which induces ERN1 activity, is often used as a tool in many different research areas, not just autophagy. Many disease models, for example, the Alzheimer's disease models focusing on Tau hyperphosphorylation or Parkinson's disease models based on alpha‐synuclein aggregation, are intertwined with proteostatic events by design 19–22 . Since EGFP is also often used in these contexts, the possibility of ERN1 influencing, for example, fusion proteins, should be considered.…”