van den Heuvel, L. | Search bioRxiv

bioRxiv2023

CTNS mRNA as a potential treatment for nephropathic cystinosis

Messenger RNA (mRNA) therapies are emerging in different disease areas, but have not yet reached the kidney field. Our aim was to study the feasibility to correct the genetic defect in nephropathic cystinosis using synthetic mRNA. Cystinosis is a prototype disorder of proximal tubular dysfunction caused by mutations in the CTNS gene, encoding the lysosomal cystine-H+ symporter cystinosin, and leading to cystine accumulation in all cells of the body. The kidneys are the first and most severely affected organs, presenting glomerular and proximal tubular dysfunction. Cysteamine is the current therapeutic standard that reduces cellular cystine levels, but has many side effects and does not restore kidney function. Here, we show that synthetic mRNA is safe and effective to reintroduce functional cystinosin using lipofection in CTNS-/- kidney cells and following direct injection in ctns-/- zebrafish larvae. CTNS mRNA therapy results in prompt lysosomal expression of the functional protein and decreases cellular cystine accumulation for up to 14 days. In the ctns-/- zebrafish, CTNS mRNA therapy improves proximal tubular reabsorption, reduces proteinuria, and restores brush border expression of the multi-ligand receptor megalin. We propose that mRNA-based therapy, if sufficient kidney targeting can be achieved, may be a new approach to treat cystinosis. Translational statementCystinosis is a systemic lysosomal storage disease caused by mutations in the CTNS (cystinosin) gene. It initially affects the kidneys and leads to kidney failure, if left untreated. The current standard therapy, cysteamine, is not curative and has many side-effects. Here we demonstrate the potential of mRNA-based therapy to swiftly restore cystinosin function and ameliorate the kidney phenotype. Future research will focus on mRNA delivery methods and targeting kidney cells in cystinosis rodent models.

genetics↗

bioRxiv2023

A workcell 1.0 for programmable and controlled operation of multiple fluidic chips in parallel.

We developed a versatile lab-on-chip (LOC) workcell that enables the design and automatic execution of experiments on LOC devices, improving how we establish, optimize, and productionalize LOC processes. Key features include direct docking and cooling of native laboratory tubes, programmable reagent mixing and dilutions, parallel operation of multiple chips, precise flowrate and pressure control, clogging detection and response, programmable microscope control, chip temperature regulation, and scheduled cleaning. All functionality is controlled seamlessly from an easy-to-write protocol file, and based on extensible hardware and software infrastructures to promote community development. To showcase the platforms use and versatility, we demonstrate a series of 5 different automated experiments at varying levels of complexity, executed across both Quake-valve and droplet microfluidic systems. In particular, the workcell was instructed to map the parameter regime that generates viable droplets, to allow a user to select diameters and production frequencies of interest for single bacterial cell encapsulation. Furthermore, three out of three days in a row, the platform successfully performed a complex 15.5h long experiment, integrating in a single automated protocol the full core workflow required by a typical protein-characterization lab: protein expression, purification, dilution generation, and quantitative binding characterization (generating 55296 images in the process). Experiments conducted through the workcell are easier to set up, offer increased control over experiment conditions and parameters, and can be heavily parallelized.

bioengineering↗