Defects in the Neuroendocrine Axis Contribute to Global Development Delay in a <i>Drosophila</i> Model of NGLY1 Deficiency

Rodriguez, Tamy Portillo; Mast, Joshua D.; Hartl, Tom A.; Lee, Tom; Sand, Peter; Perlstein, Ethan O.

doi:10.1534/g3.118.300578

Cited by 35 publications

(41 citation statements)

References 25 publications

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“…3B). 20 compounds had Z-scores greater than five in all three replicates ( Figure 3A), resulting in a suppressor hit rate of 0.781%, which is consistent with the hit rates we observed in previous whole-organism phenotypic drug repurposing screens in flies (Rodriguez et al, 2018) and yeast (Lao et al, 2019).…”

Section: As Shown Insupporting

confidence: 89%

Repurposing the aldose reductase inhibitor and diabetic neuropathy drug epalrestat for the congenital disorder of glycosylation PMM2-CDG

Iyer¹,

Murthy²,

Parton³

et al. 2019

Preprint

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Phosphomannomutase 2 deficiency, or PMM2-CDG, is the most common congenital disorder of glycosylation affecting over 1,000 patients globally. There are no approved drugs that treat the symptoms or root cause of PMM2-CDG. In order to identify clinically actionable compounds that boost human PMM2 enzyme function, we performed a multi-species drug repurposing screen using a first-ever worm model of PMM2-CDG followed by PMM2 enzyme functional studies in PMM2-CDG patient fibroblasts.Drug repurposing candidates from this study, and drug repurposing candidates from a previously published study using yeast models of PMM2-CDG, were tested for their effect on human PMM2 enzyme activity in PMM2-CDG fibroblasts. Of the 20 repurposing candidates discovered in the wormbased phenotypic screen, 12 are plant-based polyphenols. Insights from structure-activity relationships revealed epalrestat, the only antidiabetic aldose reductase inhibitor approved for use in humans, as a firstin-class PMM2 enzyme activator. Epalrestat increased PMM2 enzymatic activity in four PMM2-CDG patient fibroblast lines with genotypes R141H/F119L, R141H/E139K, R141H/N216I and R141H/F183S. PMM2 enzyme activity gains range from 30% to 400% over baseline depending on genotype.Pharmacological inhibition of aldose reductase by epalrestat may shunt glucose from the polyol pathway to glucose-1,6-bisphosphate, which is an endogenous stabilizer and coactivator of PMM2 homodimerization. Epalrestat is a safe, oral and brain penetrant drug that was approved 27 years ago in Japan to treat diabetic neuropathy in geriatric populations. We demonstrate that epalrestat is the first small molecule activator of PMM2 enzyme activity with the potential to treat peripheral neuropathy and correct the underlying enzyme deficiency in a majority of pediatric and adult PMM2-CDG patients.Keywords: Phosphomannomutase 2 deficiency, drug repurposing, PMM2-CDG, congenital disorder of glycosylation, aldose reductase inhibitor, epalrestat conserved process that occurs in all animal cells throughout development and adulthood (Chang et al, 2018). PMM2-CDG is a multi-system, multi-organ disease because a minimal level of glycosylation is required at all times in all cells of the body, with cell types or organs more or less vulnerable to the complex sequelae of hypoglycosylation. Although a clear genotype-phenotype relationship is obscured by genetic and possibly environmental modifiers, as the residual level of PMM2 enzymatic activity increases the number and severity of organ systems affected decreases. For example, patients homozygous for a mutation in the promoter of PMM2 do not get PMM2-CDG or even a mild form of PMM2-CDG but instead have hyperinsulinemic hypoglycemia and polycystic kidney disease because this mutation impairs binding by a kidney-and pancreas-specific transcription factor to a chromatin loop in the promoter of PMM2 (Cabezas et al, 2017). As another example, hypoglycosylation of the calcium channel CACNA1A caused a gain-of-function channelopathy that in turn leads to an i...

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Section: As Shown Insupporting

confidence: 89%

Repurposing the aldose reductase inhibitor and diabetic neuropathy drug epalrestat for the congenital disorder of glycosylation PMM2-CDG

Iyer¹,

Murthy²,

Parton³

et al. 2019

Preprint

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“…SKN-1A controls both basal and induced proteasome subunit gene expression and proteasome activity in C. elegans. The orthologs of PNG-1 and SKN-1A in Drosophila, mice, and human cells also control basal and induced proteasome subunit gene expression (Grimberg et al, 2011;Lee et al, 2011Lee et al, , 2013Owings et al, 2018;Radhakrishnan et al, 2010;Rodriguez et al, 2018;Steffen et al, 2010;Tomlin et al, 2017), indicating that deglycosylation of SKN-1A/Nrf1 is a conserved requirement for regulation of proteasome function in animals.…”

Section: Png-1/ngly1 and Skn-1a/nrf1 Control Proteostasismentioning

confidence: 99%

Protein Sequence Editing of SKN-1A/Nrf1 by Peptide:N-Glycanase Controls Proteasome Gene Expression

Lehrbach

Breen

Ruvkun

2019

Cell

103

120

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Graphical Abstract Highlights d PNGase edits glycosylated Asn residues of the SKN-1A transcription factor to Asp d These edits are required for SKN-1A to regulate proteasome subunit genes d Sequence-edited SKN-1A enhances proteostasis d Edits cause ER-targeted and cytosolic SKN-1 isoforms to regulate distinct genes SUMMARYThe proteasome mediates selective protein degradation and is dynamically regulated in response to proteotoxic challenges. SKN-1A/Nrf1, an endoplasmic reticulum (ER)-associated transcription factor that undergoes N-linked glycosylation, serves as a sensor of proteasome dysfunction and triggers compensatory upregulation of proteasome subunit genes. Here, we show that the PNG-1/NGLY1 peptide:N-glycanase edits the sequence of SKN-1A protein by converting particular N-glycosylated asparagine residues to aspartic acid. Genetically introducing aspartates at these N-glycosylation sites bypasses the requirement for PNG-1/NGLY1, showing that protein sequence editing rather than deglycosylation is key to SKN-1A function. This pathway is required to maintain sufficient proteasome expression and activity, and SKN-1A hyperactivation confers resistance to the proteotoxicity of human amyloid beta peptide. Deglycosylationdependent protein sequence editing explains how ER-associated and cytosolic isoforms of SKN-1 perform distinct cytoprotective functions corresponding to those of mammalian Nrf1 and Nrf2. Thus, we uncover an unexpected mechanism by which N-linked glycosylation regulates protein function and proteostasis.

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“…In an effort to phenotype and screen a homozygous loss-of-function Pngl / NGLY1 fly modeling the patient-derived C-terminal premature stop codon allele R401X, we showed that fly Pngl −/− homozygous mutant larvae are 25-fold more sensitive than heterozygotes to the toxic effects of bortezomib (Rodriguez et al, 2018). Another group reported that a Pngl RNAi-knockdown fly model of NGLY1 deficiency has constitutively reduced expression of NRF1-dependent proteasomal subunit genes, consistent with findings of hypersensitivity to bortezomib toxicity in the other models (Owings et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Drug screens of NGLY1 Deficiency worm and fly models reveal catecholamine, NRF2 and anti-inflammatory pathway activation as potential clinical approaches

Iyer¹,

Mast²,

Tsang³

et al. 2019

Disease Models &Amp; Mechanisms

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N-glycanase 1 (NGLY1) deficiency is an ultra-rare and complex monogenic glycosylation disorder that affects fewer than 40 patients globally. NGLY1 deficiency has been studied in model organisms such as yeast, worms, flies and mice. Proteasomal and mitochondrial homeostasis gene networks are controlled by the evolutionarily conserved transcriptional regulator NRF1, whose activity requires deglycosylation by NGLY1. Hypersensitivity to the proteasome inhibitor bortezomib is a common phenotype observed in whole-animal and cellular models of NGLY1 deficiency. Here, we describe unbiased phenotypic drug screens to identify FDA-approved drugs that are generally recognized as safe natural products, and novel chemical entities, that rescue growth and development of NGLY1-deficient worm and fly larvae treated with a toxic dose of bortezomib. We used image-based larval size and number assays for use in screens of a 2560-member drug-repurposing library and a 20,240-member lead-discovery library. A total of 91 validated hit compounds from primary invertebrate screens were tested in a human cell line in an NRF2 activity assay. NRF2 is a transcriptional regulator that regulates cellular redox homeostasis, and it can compensate for loss of NRF1. Plant-based polyphenols make up the largest class of hit compounds and NRF2 inducers. Catecholamines and catecholamine receptor activators make up the second largest class of hits. Steroidal and non-steroidal anti-inflammatory drugs make up the third largest class. Only one compound was active in all assays and species: the atypical antipsychotic and dopamine receptor agonist aripiprazole. Worm and fly models of NGLY1 deficiency validate therapeutic rationales for activation of NRF2 and anti-inflammatory pathways based on results in mice and human cell models, and suggest a novel therapeutic rationale for boosting catecholamine levels and/or signaling in the brain.

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Defects in the Neuroendocrine Axis Contribute to Global Development Delay in a Drosophila Model of NGLY1 Deficiency

Cited by 35 publications

References 25 publications

Repurposing the aldose reductase inhibitor and diabetic neuropathy drug epalrestat for the congenital disorder of glycosylation PMM2-CDG

Repurposing the aldose reductase inhibitor and diabetic neuropathy drug epalrestat for the congenital disorder of glycosylation PMM2-CDG

Protein Sequence Editing of SKN-1A/Nrf1 by Peptide:N-Glycanase Controls Proteasome Gene Expression

Drug screens of NGLY1 Deficiency worm and fly models reveal catecholamine, NRF2 and anti-inflammatory pathway activation as potential clinical approaches

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