Biology subjects

Hangasky, J. A.

Publications and source records attributed to Hangasky, J. A..

3 recordsLinked to original sources

bioRxiv2024

The limitation of lipidation: conversion of semaglutide from once-weekly to once-monthly dosing

The objective of this work was to develop a long-acting form of the lipidated peptide semaglutide that can be administered to humans once-monthly. Semaglutide was attached to 50 diameter hydrogel microspheres by a cleavable linker with an expected in vivo release half-life of about one-month. After a single subcutaneous dose, the pharmacokinetic parameters of released semaglutide were determined in normal mice and the bodyweight loss was determined in diet induced obese mice. The results were used to simulate the pharmacokinetics of semaglutide released from the microspheres in humans.Semaglutide tethered to microspheres by a cleavable linker could be completely released with an in vitro half-life of [~]55 days at pH 7.4. The in vivo half-life of released semaglutide was [~]30 days, and a single dose in diet-induced obese mice resulted in a lean-sparing body weight loss of 20% over 1 month, statistically the same as semaglutide dosed twice daily. Simulations indicated the microsphere-semaglutide would permit once-monthly administration in humans. The microsphere-semaglutide conjugate described here should be suitable for once-monthly dosing in humans, and the same approach should enable conversion of other lipidated peptides from once-weekly to once-monthly administration.

bioengineering↗

bioRxiv2024

Releasable hydrogel microsphere-drug conjugates as generic prodrugs for long-acting intra-tumoral therapy

Intratumoral (IT) therapy is a powerful method of controlling tumor growth, but a major unsolved problem is the rapidity that injected drugs exit tumors, limiting on-target exposure and efficacy. We have developed a generic long acting IT delivery-system in which a drug is covalently tethered to hydrogel microspheres (MS) by a cleavable linker; upon injection the conjugate forms a depot that slowly releases the drug and "bathes" the tumor for long periods. We established technology to measure tissue pharmacokinetics and studied MSs attached to SN-38, a topoisomerase 1 inhibitor. When MS[~]SN-38 was injected locally, tissues showed high levels of SN-38 with a long half-life of [~]1 week. IT MS[~]SN-38 was [~]10-fold more efficacious as an anti-tumor agent than systemic SN-38. We also propose and provide an example that long-acting IT therapy might enable safe use of two drugs with overlapping toxicities. Here, long-acting IT MS[~]SN-38 is delivered with concurrent systemic PARP inhibitor. The tumor is exposed to both drugs whereas other tissues are exposed only to the systemic drug; synergistic anti-tumor activity supported the validity of this approach. We propose use of this approach to increase efficacy and reduce toxicities of combinations of immune checkpoint inhibitors such as CTLA4 and PD-1.

cancer biology↗

bioRxiv2020

An iron (II) dependent oxygenase performs the last missing step of plant lysine catabolism

Due to low abundance in many staple food crops, the essential amino acid lysine must be produced industrially to meet global food supply needs. Despite intensive study, manipulation, and agricultural importance, the steps of plant lysine catabolism beyond the 2-oxoadipate (2OA) intermediate remain undescribed. Recently we described a missing step in the D-lysine catabolic pathway of the bacterium Pseudomonas putida in which 2OA is converted to D-2-hydroxyglutarate (D2HG) via hydroxyglutarate synthase (HglS), an enzyme belonging to the previously uncharacterized DUF1338 protein family. Here we solve the structure of HglS to 1.1[A] resolution in the substrate-free form and in complex with 2OA. Structural similarity to hydroxymandelate synthase suggested a successive decarboxylation and intramolecular hydroxylation mechanism forming 2HG in a Fe(II)- and O2-dependent manner, which is validated experimentally. 2OA specificity was mediated by a single arginine (R74), highly conserved across nearly all DUF1338 family proteins, including in 76% of plant enzymes. In Arabidopsis thaliana, a DUF1338 homolog is coexpressed with known lysine catabolism enzymes, and mutants show significant germination rate defects consistent with disrupted lysine catabolism. Structural and biochemical analysis of the Oryza sativa homolog FLO7 revealed identical activity to HglS despite low sequence identity. Our results suggest that nearly all DUF1338 containing enzymes likely catalyze the same biochemical reaction, exerting the same physiological function across bacteria and eukaryotes. SignificanceTo meet human demands, millions of tons of lysine are produced by bacterial fermentation annually due to its low abundance in staple crops. Here, we show the last missing step of lysine catabolism in nearly all plant endosperms is likely catalyzed by an iron-dependant DUF1338-containing enzyme homologous to the bacterial hydroxyglutarate synthase. Structural and bioninformatic analyses of DUF1338-containing enzymes showed high conservation of critical catalytic and specificity-conferring residues across multiple domains of life despite low sequence identity. These results suggest that the DUF1338 family evolved a specific physiological function within lysine catabolism across multiple domains of life.

molecular biology↗