Citations

Abstract Safe delivery of mRNA to the brain will revolutionize the treatment of brain tumors. While lipid nanoparticles (LNPs) are clinically most advanced non-viral delivery vehicles for therapeutic mRNA, LNP-mediated mRNA delivery to the brain remains challenging. We hypothesized that rationally designed LNPs based on extracellular vesicle mimicry would enable efficient delivery of RNA therapeutics to brain cells without undue toxicity. We engineered LNPs consisting of four components similar to the formulation used in the mRNA COVID-19 vaccines (Moderna and Pfizer-BioNTech): ionizable lipid, cholesterol, helper lipid and polyethylene glycol (PEG)-lipid. We screened ten classes of helper lipids based on lipids enriched in extracellular vesicles to engineer biomimetic LNPs and tested their GFP mRNA delivery efficacy in SIM-A9 mouse microglia cell line. Several unique LNP formulations with potent delivery efficacy (>90% cells transfected) and stable GFP expression kinetics (5 days) were identified. LNP formulations with high transfection efficacy were then tested in vivo for luciferase mRNA delivery via intrathecal injection in C57BL/6 mice. Luciferase expression in vivo confirmed widespread mRNA delivery in the brain. We then tested Cre recombinase mRNA delivery in Ai9 mouse to identify LNP-targeted cells via flow cytometry and histology. Flow cytometry and expansion microscopy confirmed Cre recombinase mRNA delivery to a variety of brain cells, including microglia (75-90%), neurons (31-40%), neural stem cells (39-62%), oligodendrocytes (70-90%), and astrocytes (44-76%). LNPs were further evaluated for Cas9 mRNA and CD81 sgRNA delivery in C57BL/6 mouse brains to assess brain-targeted gene editing. Sanger sequencing showed that CRISPR-Cas9 editing was successful in ~40% of cells in the mouse brain. In summary, we engineered extracellular vesicle-based LNP library that can deliver RNA therapeutics to a variety of brain cells in vivo. With further development, this technology could potentially enable genetic and epigenetic therapies targeting drivers of brain tumors.

Abstract A subset of stem-like cells in glioblastoma (GBM; GSC) underlies tumor propagation, therapeutic resistance, and tumor recurrence. Immune evasion is critical for GSCs to carry out these functions. However, the molecular mechanisms employed by GSCs to escape antitumor immunity remain largely unknown. The reprogramming transcription factors Oct4 and Sox2 function as core multipotency factors and play an essential role in the formation and maintenance of GSCs, but the roles of these transcription factors in GSC immune escape have not been well explored. Here we examine how Oct4/Sox2 coexpression contributes to the immunosuppressive phenotype of GSCs. Combined transcription profiling and functional studies of Oct4/Sox2 coexpressing GSCs and differentiated GBM cells demonstrated that Oct4 and Sox2 cooperatively induce an immunosuppressive transcriptome consisting of multiple immunosuppressive checkpoints (i.e., PD-L1, CD70, A2aR, TDO) and dysregulation of cytokines and chemokines that are associated with an immunosuppressive tumor microenvironment. Mechanistically, induction and function of BRD/H3k27Ac-dependent immunosuppressive genes played a role in the immunosuppressive phenotype of GSCs. Pan-BET bromodomain inhibitors (e.g., JQ1) and shBRD4 constructs significantly inhibited the immunosuppressive transcriptome and immunosuppressive biological responses induced by Oct4/Sox2. Our findings identify targetable mechanisms by which tumor-propagating GSCs contribute to the immunosuppressive microenvironment in GBM. Significance: This report identifies mechanisms by which the reprogramming transcription factors Oct4 and Sox2 function to drive the immunomodulatory transcriptome of GSCs and contribute to the immunosuppressive microenvironment in GBM.

Kidney diseases secondary to several pathogeneses affect millions of people worldwide and have become increasingly recognized as a global public health problem. Recent evidence suggests that cellular senescence plays an important role in the pathogenesis of different forms of renal damage, including acute and chronic kidney disease, and renal transplantation. Renal senescence involves cell cycle arrest and affects several cellular pathways, manifesting in downregulation of klotho, elevated expression of cyclin-dependent kinase inhibitors, cellular telomere shortening, and oxidative stress. Furthermore, senescent cells might induce kidney injury by paracrine release of inflammatory factors. Yet, cellular senescence may be renoprotective during development and in some models of renal diseases, reflecting the yin/yang duality of cellular senescence. This review provides an overview of the role of this emerging player in renal injury, with emphasis on new findings of cellular senescence.