Biology subjects

Lin, G.-Y.

Publications and source records attributed to Lin, G.-Y..

3 recordsLinked to original sources

bioRxiv2023

Increased FAN1 expression by mRNA-LNP attenuates CAG repeat expansion in Huntington patients' iPSC-derived astrocytes

Expansion of repeat sequences within the human genome can lead to disease pathogenesis, such as Huntingtons Disease, primarily affecting the nervous system. Genome-wide association studies (GWAS) of age-at-onset in Huntingtons disease (HD) patients demonstrated DNA mismatch repair (MMR) genes are modifiers of somatic expansion and may be potential therapeutic targets for repeat expansion (RE) disorders. FAN1, a Fanconi anemia-associated nuclease, has been reported as an influencer of repeat expansion in the RE mouse models. Here, we show the first demonstration that FAN1 knock-out in HD patient-derived fibroblasts and results in increased CAG repeat length. We also develop a robust novel cell-based platform using stem cell technology to produce the HD patients iPSC-derived astrocytes (iAstro). This platform is a disease-relevant system and has a significantly wider assay window, making it more suitable to assess the effect of gene modulation on CAG repeats. A substantial and exponential increase in repeat instability was exhibited in this HD patients iPSC-derived astrocytes platform. Over-expression of FAN1 protein via FAN1 plasmid transfection in this platform reduced CAG repeat instability, suggesting that upregulation of FAN1 protein may have a potential protective effect in CAG repeat expansion for a therapeutic setting. We leveraged the mRNA-LNP modality to enhance FAN1 protein expression and revealed that codon-optimized FAN1 mRNA-LNP robustly prevented increased CAG repeat in HD patients iPSC-derived astrocytes platform. The data from these cell-based platforms highlight that FAN1 plays a protective role in attenuating expanded somatic HTT CAG repeats and shed light on new therapeutic directions against repeat expansion disorders.

neuroscience↗

bioRxiv2023

Targeting ABCB4 using mRNA-LNP for the treatment of rare liver diseases

Mutations in the ABCB4 gene lead to a wide-spectrum of rare liver diseases including progressive familial intrahepatic cholestasis type 3 (PFIC3) and low-phospholipid associated cholelithiasis (LPAC) syndrome. PFIC3 patients develop symptoms during late infancy, including severe itching, jaundice, and failure to thrive. The condition may progress to liver failure during childhood or adulthood. This is a highly unmet medical condition where liver transplantation is the only option to correct this disease. Recently, exciting data suggested that restoration of the ABCB4 function via gene replacement could rescue liver phenotypes associated with ABCB4 dysfunction in a preclinical PFIC3 mouse model. Here, we used mRNA LNP platform to determine expression and durability of ABCB4 in the liver of wildtype mice. In addition, we generated Abcb4-/- mice to study the efficacy of systemic delivery of ABCB4 mRNA LNP. We observed a robust and durable expression of hABCB4 up to 72 hours post systemic dosing in the liver of wild-type mice. Systemic administration of hABCB4 mRNA achieved a remarkable restoration of phosphatidylcholine levels in bile, a significant decrease in liver stiffness as measured by shear wave elastography, and amelioration of liver histopathology including fibrosis and ductular reaction. We conclude that administration of hABCB4 mRNA LNPs was sufficient to ameliorate fibrosis markers in the PFIC3 mouse model. Our data suggests that gene replacement using mRNA LNP modality could provide an excellent opportunity for patients with biliary diseases.

molecular biology↗

bioRxiv2019

Data-Driven Design of Diagnostic Kits and Therapeutic Peptides

To ensure a physicochemically desired sequence motif to adapt a specific type of secondary structures, we compile an -helix database allowing complicate search patterns to facilitate a data-driven design of therapeutic peptides. Nearly 1.7 million helical peptides in >130 thousand proteins are extracted along with their interacting partners from the protein data bank (PDB). The sequences of the peptides are indexed with patterns and gaps and deposited in our Therapeutic Peptide Design dataBase (TP-DB). We here demonstrate its utility in three medicinal design cases. By our pattern-based search engine but not PHI-BLAST, we can identify a pathogenic protein, Helicobacter pylori neutrophil-activating protein (HP-NAP), a virulence factor of H. pylori, which contains a motif DYKYLE that belongs to the affinity determinant motif DYKXX[DE] of the FLAG-tag and can be recognized by the anti-FLAG M2 antibody. By doing so, the known purification-tag-specific antibody is repurposed into a diagnostic kit for H. pylori. Also by leveraging TP-DB, we discovered a stretch of helical peptide matching the potent membrane-insertion pattern WXXWXXW, elucidated by MD simulations. The newly synthesized peptide has a better minimal inhibitory concentration (MIC) and much lower cytotoxicity against Candida albicans (fungus) than that of previously characterized homologous antimicrobial peptides. In a similar vein, taking the discontinued anchoring residues in the helix-helix interaction interface as the search pattern, TP-DB returns several helical peptides as potential tumor suppressors of hepatocellular carcinoma (HCC) whose helicity and binding affinity were examined by MD simulations. Taken together, we believe that TP-DB and its pattern-based search engine provide a new opportunity for a (secondary-)structure-based design of peptide drugs and diagnostic kits for pathogens without inferring evolutionary homology between sequences sharing the same pattern. TP-DB is made available at http://dyn.life.nthu.edu.tw/design/.

bioinformatics↗