Biology subjects

Ranasinghe, M.

Publications and source records attributed to Ranasinghe, M..

3 recordsLinked to original sources

bioRxiv2025

Lipid Nanoparticles with Aptamers Enable Targeted mRNA Delivery to CD4⁺ T Cells

In vivo genetic engineering of T cells could overcome the logistical, biological, and safety challenges of ex vivo modification, but effective and safe delivery systems remain limited by a lack of cellular specificity. Here, we developed aptamer-functionalized lipid nanoparticles (LNPs) for targeted mRNA delivery to CD4+ T cells, employing both a validated CD4-binding aptamer (Apt62) and novel aptamers generated using our proprietary transformer-based AI language model, AptaBLE. LNPs formulated with ionizable lipid SM102 or MC3 and conjugated with aptamers at controlled densities were physiochemically characterized and assessed for binding, in vitro transfection, in vivo biodistribution, and safety evaluation. Aptamer-functionalized LNPs demonstrated selective nanomolar binding to recombinant CD4, achieved enhanced transfection of CD4+ versus CD4- T cells in vitro, and significantly enriched mRNA delivery to immune-rich tissues in vivo, achieving up to 70-fold spleen signal enhancement with SM102 formulations compared to non-targeted controls, while maintaining suitable safety profiles. Overall, these findings demonstrate aptamer-functionalized LNPs, augmented by AI-guided aptamer design, as a tunable, non-immunogenic platform for in vivo T cell engineering. HighlightsO_LIAptamer-functionalized LNPs enable selective mRNA delivery to CD4+ immune cells rich organs. C_LIO_LIAptamer-functionalized LNPs maintain a favorable systemic safety profile in vivo. C_LIO_LIAI-guided AptaBLE platform generated functional aptamers validated in nanoparticle delivery. C_LI

molecular biology↗

bioRxiv2023

DNA supercoiling-induced shapes alter minicircle hydrodynamic properties

DNA in cells is organized in negatively supercoiled loops. The resulting torsional and bending strain allows DNA to adopt a surprisingly wide variety of 3-D shapes. This interplay between negative supercoiling, looping, and shape influences how DNA is stored, replicated, transcribed, repaired, and likely every other aspect of DNA activity. To understand the consequences of negative supercoiling and curvature on the hydrodynamic properties of DNA, we submitted 336 bp and 672 bp DNA minicircles to analytical ultracentrifugation (AUC). We found that the diffusion coefficient, sedimentation coefficient, and the DNA hydrodynamic radius strongly depended on circularity, loop length, and degree of negative supercoiling. Because AUC cannot ascertain shape beyond degree of non-globularity, we applied linear elasticity theory to predict DNA shapes, and combined these with hydrodynamic calculations to interpret the AUC data, with reasonable agreement between theory and experiment. These complementary approaches, together with earlier electron cryotomography data, provide a framework for understanding and predicting the effects of supercoiling on the shape and hydrodynamic properties of DNA.

biophysics↗

bioRxiv2019

LITE-1 Mediates X-ray Avoidance Response in C. elegans

We report the finding that C. elegans display X-ray avoidance behavior at high but well tolerated doses, and that this behavior appears to require LITE-1, a gustatory receptor that has been implicated in UV avoidance behavior. We recorded acute behavioral responses of wildtype worms to increasing intensities of X-ray stimulation and found a positive stimulation-response relationship. Mutant strains of worms with dysfunctional photoreceptor proteins LITE-1 and GUR-3 were assayed, and the X-ray avoidance response was found to be nearly absent in LITE-1 mutants but not GUR-3 mutants, suggesting a prominent role for LITE-1 in the detection of X-rays. These findings may be important for developing optogenetics tools to stimulate cells in deep tissue using X-rays, for understanding the mechanism of LITE-1 signaling, and for understanding how organisms may respond to radiation.

neuroscience↗