Autosomal recessive loss-of-function mutations in N-glycanase 1 (NGLY1) cause NGLY1 deficiency, the only known human disease of deglycosylation. Patients present with developmental delay, movement disorder, seizures, liver dysfunction and alacrima. NGLY1 is a conserved cytoplasmic component of the Endoplasmic Reticulum Associated Degradation (ERAD) pathway. ERAD clears misfolded proteins from the ER lumen. However, it is unclear how loss of NGLY1 function impacts ERAD and other cellular processes and results in the constellation of problems associated with NGLY1 deficiency. To understand how loss of NGLY1 contributes to disease, we developed a Drosophila model of NGLY1 deficiency. Loss of NGLY1 function resulted in developmental delay and lethality. We used RNAseq to determine which processes are misregulated in the absence of NGLY1. Transcriptome analysis showed no evidence of ER stress upon NGLY1 knockdown. However, loss of NGLY1 resulted in a strong signature of NRF1 dysfunction among downregulated genes, as evidenced by an enrichment of genes encoding proteasome components and proteins involved in oxidation-reduction. A number of transcriptome changes also suggested potential therapeutic interventions, including dysregulation of GlcNAc synthesis and upregulation of the heat shock response. We show that increasing the function of both pathways rescues lethality. Together, transcriptome analysis in a Drosophila model of NGLY1 deficiency provides insight into potential therapeutic approaches.

N-glycanase deficiency, or NGLY1 deficiency, is an extremely rare human genetic disease. N-glycanase, encoded by the gene NGLY1, is an important enzyme involved in protein deglycosylation of misfolded proteins. Deglycosylation of misfolded proteins precedes the endoplasmic reticulum (ER)-associated degradation (ERAD) process. NGLY1 patients produce little or no N-glycanase (Ngly1), and the symptoms include global developmental delay, frequent seizures, complex hyperkinetic movement disorder, difficulty in swallowing/aspiration, liver dysfunction, and a lack of tears. Unfortunately, there has not been any therapeutic option available for this rare disease so far. Recently, a proposed molecular mechanism for NGLY1 deficiency suggested that endo-β-N-acetylglucosaminidase (ENGase) inhibitors may be promising therapeutics for NGLY1 patients. Herein, we performed structure-based virtual screening of FDA-approved drug database on this ENGase target to enable repurposing of existing drugs. Several Proton Pump Inhibitors (PPIs), a series of substituted 1 H-Benzo [d] imidazole, and 1H-imidazo [4,5-b] pyridines, among other scaffolds, have been identified as potent ENGase inhibitors. An electrophoretic mobility shift assay was employed to assess the inhibition of ENGase activity by these PPIs. Our efforts led to the discovery of Rabeprazole Sodium as the most promising hit with an IC50 of 4.47±0.44 μM. This is the first report that describes the discovery of small molecule ENGase inhibitors, which can potentially be used for the treatment of human NGLY1 deficiency.

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The aim of the present study is to synthesize Pluronic F127-polyethylenimine-folate (PF127-PEI-FA) copolymer, construct a mixed micelle system with PF127-PEI-FA copolymer and Pluronic P123 (PP123) and to evaluate the potential of these mixed micelles as an oral drug delivery system for paclitaxel (PTX). The results of intestinal absorption revealed that the PTX-loaded micelles displayed superior permeability across intestinal barrier than free drug and PF127-PEI-FA/PP123 mixed micelles exhibited the strongest permeability across intestinal barrier. These results were also proved by the studies on cytotoxicity and cell uptake tests. The mechanism was demonstrated in connection with inhibition of the efflux mediated by intestinal P-glycoprotein (P-gp) and enhancement of the electrostatic interaction of positive micelles with the negative intestinal epithelial cells, thereby promoting the permeation across the intestinal wall. The presence of verapamil and Pluronic both improved the intestinal absorption of PTX, which further certified the effect of Pluronic on P-gp inhibition. Pharmacokinetic study demonstrated that the area under the plasma concentration-time curve (AUC(0→36 h)) of PTX-loaded micelles was three times greater than the PTX solution (dissolved in a 50/50 (vol/vol) mixture of Cremophore EL/dehydrated ethanol) (p < 0.05). In general PF127-PEI-FA/PP123 mixed micelles were proved to be potential oral drug delivery system for PTX.