Abstract Lymphangioleiomyomatosis (LAM) is a genetic disorder caused by bi-allelic inactivating mutations in tumor suppressor genes TSC1 or TSC2, leading to progressive lung destruction and eventually the requirement for lung transplantation. Rapalogs, the only FDA-approved treatments for LAM, induce a cytostatic effect with stabilized lung function. However, lung function continues to decline upon treatment cessation. Thus, there is an urgent need for better treatment, potentially leading to a cure for this devastating disease. The monogenetic nature of LAM makes messenger RNA (mRNA) replacement an attractive therapeutic modality, which requires safe and efficacious delivery of functional mRNA to the lung and specifically into TSC- deficient cells. We have developed lung-specific synthetic lipid nanoparticles (LNPs) and showed in our preliminary data that in vivo organ-selectivity of LNPs can be precisely tuned by changing the linker structure in the lipidoid tails without complicating the LNPs formulation. Furthermore, we developed LAM cell-targeting hybrid LNPs that efficiently deliver functional TSC2 mRNA into TSC2-deficient cells and suppress mTORC1 pathway. mRNA replacement therapy significantly reduced tumor burdens in preclinical LAM models. Remarkably, mRNA therapy induced T cell tumor infiltration in the otherwise immune cold tumor microenvironment. We hypothesize: 1) improved lung-specific tumor-targeting LNPs will assist developing mRNA therapy for LAM, which provides a novel therapeutic strategy to achieve durable effects and complete response; 2) LNP-assisted mRNA therapy can reprogram LAM-like cells back to a “normal” state without affecting normal tissue, and can re-normalize LAM microenvironment; 3) multi-omic single cell analysis will reveal mechanism of action of mRNA therapy and help improve LNP design. Our hypotheses will be tested in the following Aims: Aim 1. To develop and optimize lung-specific synthetic lipid nanoparticles for LAM-targeted mRNA therapy. Aim 2. To determine therapeutic efficacy of LAM-targeting nanoparticle-assisted mRNA therapy for LAM. Aim 3. To determine mRNA therapy-induced LAM cell reprogramming and LAM microenvironment remodeling by integrative single cell multiomic analyses. The scientific and preclinical impact of this project are 1) development of LAM cell-targeted mRNA therapy; 2) proof-of-concept that mRNA therapy can achieve durable response; 3) molecular understanding of LAM cell reprogramming and LAM microenvironment restoration by mRNA therapy. The success of this study will open a new therapeutic paradigm of mRNA therapy with the potential of durable effects and complete remissions.