Advanced Therapeutics

The blood-brain barrier (BBB), hinders the distribution of therapeutics, intended for treatment of diseases of the brain. A twelve-amino acid peptide, termed MTfp, was derived from MTf, and retains the ability to cross the BBB intact and ferry cargo into intacellular organelles within neurons, glia and microglia in the brain. A novel MTfp-siRNA peptide-oligonucleotide conjugate (POC), directed against NOX4, a gene known to potentiate ischemic stroke, was chemically synthesized. The MTfp-NOX4 siRNA POC traversed the BBB, resulting in the knockdown of NOX4 expression in the brain. Following induction of ischemic stroke, animals treated with the POC exhibited significantly smaller infarcts; accompanied by significant protection against neurological deterioration and improved recovery. The data demonstrates that the MTfp portion, of this novel POC, can facilitate BBB transcytosis; where the siRNA moiety can elicit effective therapeutic knockdown of a gene associated with a disease of the central nervous system (CNS). This is a general platform to transport therapeutics to the CNS and thereby, offers new avenues for potential treatments of neuropathologies that are currently refractory to existing therapies.

Biotherapeutics are required to achieve high remission rates in patients with severe ulcerative colitis (UC); however, adverse effects, complex dosing regimens, administration routes, and low patient compliance may limit their widespread clinical use. Given the localized nature of UC, this study aimed to develop and evaluate a localized delivery strategy for infliximab (IFX), an anti-tumor necrosis factor- (TNF-) monoclonal antibody (mAb) recommended by the European Crohns and Colitis Organization (ECCO) and the American Crohns & Colitis Foundation for moderately-to-severely active UC. Exploiting the intrinsic biocompatibility, mucoadhesivity, and protein-entrapment capacity of lipid mesophases (LMPs), IFX was encapsulated within the gel matrix, providing protection against enzymatic and environmental degradation. IFX-loaded LMPs were designed for targeted delivery to inflamed colonic tissues via rectal or oral administration, with patient-centric oral dosage forms manufactured using a 3D printing approach. A comprehensive physicochemical characterization was performed to elucidate mesophase self-assembly and its relationship with IFX release profiles in biorelevant fluids. Therapeutic efficacy was evaluated in vivo using a dextran sulfate sodium (DSS)-induced colitis rat model, which demonstrated rectal gel retention for at least 8 h and colonic targeting of the oral formulation within 6 h. Under severe inflammatory conditions, LMP-based formulations reduced disease activity, inflammatory biomarkers (TNF- and fecal lactoferrin), and colon shortening to values comparable to those of healthy controls, outperforming the therapeutic efficacy of subcutaneous IFX. Overall, this study establishes a biocompatible delivery platform that enables targeted colonic IFX release and suppresses systemic absorption, representing a promising advancement in the biotherapeutic treatment of UC.

Cisplatin-induced acute kidney injury (CI-AKI) is a significant co-morbidity of chemotherapeutic regimens. While this condition is associated with substantially lower survival and increased economic burden, there is no pharmacological agent to effectively treat CI-AKI. The disease is hallmarked by acute tubular necrosis of the proximal tubular epithelial cells primarily due to increased oxidative stress. In our prior work, we developed a highly-selective kidney-targeted mesoscale nanoparticle (MNP) that accumulates primarily in the renal proximal tubular epithelial cells while exhibiting no toxicity. Here, we found that MNPs exhibit renal-selective targeting in multiple mouse models of tumor growth with virtually no tumor accumulation. We then evaluated the therapeutic efficacy of MNPs loaded with the reactive oxygen species scavenger edaravone in a mouse model of CI-AKI. We found a marked and significant therapeutic effect with this approach as compared to free drug or empty control MNPs, including improved renal function, histology, and diminution of oxidative stress. These results indicated that renal-selective MNP edaravone delivery holds substantial potential in the treatment of acute kidney injury among patients undergoing cisplatin-based chemotherapy.

Chimeric antigen receptor (CAR)-modified macrophages (CAR-Ms) are a promising approach for the treatment of solid tumors due to its high infiltration and immune-regulation activity. Prostate cancer is a typical solid tumor associated with highly immunosuppressive microenvironment. To date, the potential application of CAR-M cell therapy in prostate cancer has been infrequently explored. The prostate-specific membrane antigen (PSMA) functions as a specific biomarker for prostate cancer. In this study, we assessed the antitumor efficacy of PSMA-targeted CAR-Ms in preclinical models. CAR-Ms were engineered to express a PSMA-specific single-chain variable fragment (scFv) and co-stimulatory domains. In vitro data demonstrated specific cytotoxicity of CAR-Ms against PSMA-expressing prostate cancer cells, which was further supported by transcriptome analysis demonstrating the pro-inflammatory phenotypes of CAR-Ms. In vivo studies using xenograft mouse models confirmed significant tumor regression after administration of PSMA-targeted CAR-Ms compared to controls. Histopathological analysis showed infiltration of CAR-Ms into tumor tissues without off-target toxicity. These results highlight the strong antitumor activity and safety of PSMA-targeted CAR-Ms, supporting their potential as a new immunotherapy for prostate cancer.

Anthracycline induced cardiotoxicity is a significant problem for oncologists and cancer patients. The leading cause of non-cancer death in cancer patients and survivors is heart failure, which is frequently attributed to the exposure to chemotherapeutics like anthracyclines. The most notorious of these chemotherapies is doxorubicin, which causes cardiac contractile dysfunction that in some cases is irreversible. In this study, we report the development of NanoDMX, a phosphatidylserine-containing liposomal formulation of DMX5804, a small molecule inhibitor of MAP4K4, and demonstrate that its administration prevents doxorubicin-induced left ventricular dysfunction in mice. Additionally, we demonstrate that DMX-5804 protects cardiomyocytes in vitro through a combination of mechanisms outside of the expected route of suppressing the JNK pathway. Overall, we demonstrate that the use of NanoDMX, a novel liposomal system using both DMX-5804 and phosphatidylserine, can prevent the damage induced by doxorubicin over the course of a single high dose in vivo model.

PurposeTo develop a clinically feasible and practical therapy for multi-ocular protection following ocular injury by using a thermosensitive drug delivery system (DDS) for sustained delivery of TNF- and VEGF inhibitors to the eye. MethodsA thermosensitive, biodegradable hydrogel DDS (PLGA-PEG-PLGA triblock polymer) loaded with 0.7mg of adalimumab and 1.4 mg of aflibercept was injected subconjunctivally in Dutch-belted pigmented rabbits after corneal alkali injury. The polymer was tuned to transition from liquid to gel upon contact with body temperature without need of a catalyst. Control rabbits received 2mg of IgG loaded DDS or 1.4mg aflibercept loaded DDS. Animals were followed for 3 months and assessed for tolerability and prevention of corneal neovascularization (NV), improvement of corneal re-epithelialization, inhibition of retinal ganglion cell (RGC) and optic nerve axon loss, and inhibition of immune cell infiltration into the cornea. Drug release kinetics was assessed in vivo using aqueous humor protein analysis. ResultsA single subconjunctival administration of dual anti-TNF/anti-VEGF DDS achieved sustained 3-month delivery of antibodies to the anterior chamber, iris, ciliary body, and retina. Administration after corneal alkali burn suppressed CD45+ immune cell infiltration into the cornea, completely inhibited cornea NV for 3 months, accelerated corneal re-epithelialization and wound healing, and prevented RGC and optic nerve axon loss at 3 months. In contrast, anti-VEGF alone or IgG DDS treatment led to persistent corneal epithelial defect, increased infiltration of CD45+ immune cells into the cornea, and significant loss of RGCs and optic nerve axons at 3 months. Aqueous humor protein analysis showed first-order release kinetics without adverse effects at the injection site. ConclusionSustained concomitant inhibition of TNF- and VEGF using a biodegradable, slow-release thermosensitive DDS provides significant ocular protection and prevents corneal neovascularization and irreversible damage to retina and optic nerve after corneal alkali injury. This therapeutic approach has the potential to dramatically improve the outcomes of severe ocular injuries in patients.

Lysosomal targeting chimeras (LYTACs) represent an emerging class of bifunctional molecules that bridge extracellular target proteins with intrinsic lysosome-targeting receptors (LTRs) on the cell surface, facilitating endocytic internalization and subsequent lysosomal degradation of the targets. However, the therapeutic potential of LYTACs has been limited by the scarcity of suitable intrinsic LTRs. We previously identified an aptamer, SAPT8, that selectively targets nucleolin, a shuttling protein overexpressed on the surface of pathogenic FLSs in rheumatoid arthritis (RA), and induced its lysosomal degradation. In this study, we repurposed SAPT8 as a tumor-targeting and lysosome-directed ligand, leveraging the elevated expression of NCL on tumor cell surfaces. By conjugating SAPT8 with either the c-Met-binding aptamer SL1 or the small molecule inhibitor Tepotinib, we engineered novel LYTACs that demonstrated potent tumor-targeting capability and induced concurrent degradation of both c-Met and NCL, leading to significant antitumor effects. Furthermore, fusion of SAPT8 with VEGFR-2-targeting aptamer Apt02 generated LYTACs that simultaneously degraded VEGFR-2 and NCL, effectively suppressing RA-FLS activity. These results establish SAPT8 as a versatile platform for developing next-generation LYTACs, overcoming current limitations in extracellular protein degradation by circumventing dependence on endogenous LTRs. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=69 SRC="FIGDIR/small/672993v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@975b74org.highwire.dtl.DTLVardef@f55565org.highwire.dtl.DTLVardef@b9639corg.highwire.dtl.DTLVardef@13aaba7_HPS_FORMAT_FIGEXP M_FIG C_FIG

Dysbiosis is linked to autoimmune diseases such as rheumatoid arthritis (RA), where microbial metabolites, such as short chain fatty acids (SCFAs), mediate the so-called gut-joint axis. The therapeutic potential of SCFAs is limited due to the frequent and high oral dosage requirements. RA is characterized by aberrant activation of peripheral T cells and myeloid cells. We aim to deliver butyrate, an SCFA, directly to the lymphatics using a polymeric micelle as a butyrate prodrug, creating a depot for inducing long-lasting immunomodulatory effects. Notably, negatively charged micelles (Neg-ButM) demonstrate superior efficacy in targeting the lymphatics post-subcutaneous administration, and were retained in the draining lymph nodes, spleen, and liver for over a month. In a mouse RA model, we found that Neg-ButM substantially mitigated arthritis symptoms and promoted tolerogenic phenotypes in T cells and myeloid cells, both locally and systemically. These findings suggest potential applications of this approach in treating inflammatory autoimmune diseases.

Adoptive cell therapies used to treat advanced prostate cancer are being developed to target several tumor-associated antigens, including prostate-specific membrane antigen (PSMA). Chimeric antigen receptor (CAR) T cell therapy using the single chain variable fragment (scFv) derived from the humanized murine mAb clone, J591, as the antigen-binding domain has shown promising anti-tumor activity. However, it has also been associated with macrophage activation syndrome and other unwanted toxicities, highlighting the need for more specific and human-derived antigen-binders with optimized construct designs for improved safety and efficacy. Here, we optimize a human scFv-based PSMA-targeted CAR (hPSMA-CAR) with highly selective PSMA targeting. We further introduce a membrane-bound IL-12 (mbIL12) molecule, which enhances potency with increased T cell expansion, IFNy production and anti-tumor cell activity in vitro. Using two clinically-relevant bone-metastatic prostate cancer models, we show that mbIL12-engineered hPSMA-CAR T cells drive potent in vivo anti-tumor responses. In summary, we have developed a promising therapeutic that has potential to promote safe and effective treatment of advanced PSMA+ prostate cancer.

SARS-CoV-2 can infect cells through endocytic uptake, a process which is targeted by inhibition of lysosomal proteases. However, clinically this approach to treat viral infections has afforded mixed results, with some studies detailing an oral regimen of hydroxychloroquine accompanied by significant off-target toxicities. We rationalized that an organelle-targeted approach will avoid toxicity while increasing the concentration of the drug at the target. Here we describe a lysosome-targeted, mefloquine-loaded poly(glycerol monostearate-co-{varepsilon}-caprolactone) nanoparticle (MFQ-NP) for pulmonary delivery via inhalation. Mefloquine is a more effective inhibitor of viral endocytosis than hydroxychloroquine in cellular models of COVID-19. MFQ-NPs are less toxic than molecular mefloquine, 100-150 nm in diameter, and possess a negative surface charge which facilitates uptake via endocytosis allowing inhibition of lysosomal proteases. MFQ-NPs inhibit coronavirus infection in mouse MHV-A59 and human OC43 coronavirus model systems and inhibit SARS-CoV-2-WA1 and its Omicron variant in a human lung epithelium model. This study demonstrates that organelle-targeted delivery is an effective means to inhibit viral infection.

Endometriosis is a chronic, incurable disease. Due to limited efficacy, high recurrence rates, and serious side effects of current treatments, development of new, targeted, non-hormonal therapies is urgently needed. We previously reported that niclosamide, an FDA-approved anthelmintic drug, attenuates endometriotic lesion growth. We further identified folate receptor-{beta} (FR{beta})-positive macrophages as contributors to disease progression. Significantly, niclosamide inhibits FR{beta}+ macrophages and reduces inflammation, innervation, and angiogenesis. To develop niclosamide as a non-hormonal and selective immune cell-targeted therapy for endometriosis, we engineered a folic acid-conjugated 2-deoxyglucose dendrimer (FA-2DG-D) using click chemistry to enable selective FR{beta}-mediated uptake. Conjugation of niclosamide to FA-2DG-D yielded a targeted nanotherapeutic (FA-2DG-D-Niclo) with enhanced aqueous solubility, controlled intracellular release, and excellent batch-to-batch reproducibility. In a mouse model of endometriosis, FA-2DG-D demonstrated lesion-specific accumulation and selective internalization by FR{beta} macrophages with minimal off-target organ retention. A single intraperitoneal dose of FA-2DG-D-Niclo (25 or 50 mg/kg/bw of niclosamide) significantly reduced FR{beta} macrophage burden, suppressed lesion number and volume, and markedly improved endometriosis-associated hyperalgesia at two weeks post-treatment. Together, these findings establish FR{beta} macrophages as a potential target in endometriosis and present FA-2DG-D-Niclo as a non-hormonal, macrophage-focused nanomedicine for precise and effective endometriosis treatment. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/704463v2_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@d0101corg.highwire.dtl.DTLVardef@1d1a0bborg.highwire.dtl.DTLVardef@18f9271org.highwire.dtl.DTLVardef@d76bc7_HPS_FORMAT_FIGEXP M_FIG C_FIG

Fibrosis is a significant mortality factor and health concern, promoting organ malfunction as well as immune and chemical resistance. Among the different fibroproliferative diseases, idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic interstitial lung disease (ILD) with limited therapeutic options. Autotaxin (ATX), an established therapeutic target in IPF, is a secreted lysophospholipase D that catalyses the extracellular production of lysophosphatidic acid (LPA), a growth factor-like signalling phospholipid. The many pathologic effects of LPA in the lung include the suppression of peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}), a therapeutic target in metabolic disorders, which are frequent comorbidities of IPF associated with unfavourable prognosis. In this report, we introduce EL244, the first-in-class dual ATX inhibitor and PPAR{gamma} agonist, which is endowed with drug-like properties. Developed through chemoinformatic repositioning, innovative rational design, targeted synthesis and pharmacological characterization, EL244 exhibited favourable ADMET and PK/PD profiles. Remarkably, EL244 inhalation, which alleviates systemic toxicity concerns, decreased pulmonary LPA levels and related effects in pulmonary cells, and attenuated bleomycin (BLM)-induced pulmonary fibrosis, restoring respiratory functions. Therefore, EL244 emerges as a promising candidate for the inhaled treatment of IPF and ILDs.

Hyperpigmentation is a common skin condition with serious psychosocial consequences. Decapeptide-12, a novel peptide, has been found to be safer than hydroquinone in reducing content of melanin, with efficacy up to more than 50% upon 16 weeks of twice daily treatment. However, the peptide suffers from limited transcutaneous penetration due to its hydrophilicity and large molecular weight. Therefore, decapeptide-12 was modified by adding a palmitate chain in an attempt to overcome this limitation. We also tested the effects of chemical penetration enhancers and microneedles to deliver two peptides through skin. Enhanced skin permeation was found using an in vitro human skin permeation model. Moreover, we examined peptide retention of different formulations in skin. Our data showed that palm-peptides in microneedle patch was the most effective.

Non-hormonal products for on-demand contraception are a global health technology gap, motivating us to pursue the use of sperm-binding monoclonal antibodies as a strategy to enable safe, effective, desirable, on-demand contraception. Here, using cGMP-compliant Nicotiana-expression system, we produce an ultra-potent sperm-binding IgG antibody possessing 6 Fab arms per molecule that bind a well-established contraceptive antigen target, CD52g. We term this hexavalent antibody "Fab-IgG-Fab" (FIF) to reflect its molecular orientation. The Nicotiana-produced FIF exhibits at least 10-fold greater sperm agglutination potency and kinetics than the parent IgG, while preserving Fc-mediated trapping of individual spermatozoa in mucus. We formulate the Nicotiana-produced FIF into a polyvinyl alcohol-based water-soluble contraceptive film, and evaluate its potency in reducing progressively motile sperm in the sheep vagina. Two minutes after vaginal instillation of human semen, no progressively motile sperm are recovered from the vaginas of sheep receiving FIF-Film. In contrast, high numbers of progressively motile sperm are recovered from sheep receiving a placebo film control. Our work supports the potential of highly multivalent contraceptive antibodies to provide safe, effective, on-demand non-hormonal contraception.

Even after chimeric antigen receptor (CAR)-based immunotherapy has dramatically changed therapeutic approaches for malignancies, balancing therapeutic efficacy with labor and financial cost remains a major problem for immunotherapy. Current study developed a cost-effective and enhanced approach to chimeric antigen receptor (CAR)-macrophage therapy for cancer and demonstrated its therapeutic effects by repeated administration of anti-HER2 CAR macrophages generated from human pluripotent stem cell (PSC)-derived immortalized myeloid cell lines (ML). These ML-derived CAR macrophages (CAR-ML-MPs) exhibit potent antigen-specific killing activity against HER2-expressing tumor cells by phagocytosis in vitro and effectively inhibit tumor progression in vivo, which is enhanced by repeated administration. CAR-ML-MPs provide a promising off-the-shelf cellular resource for tumor adoptive cell immunotherapy, solving the cost and time problems associated with conventional CAR-based immunotherapy.

Burn wounds are a common traumatic injury that impair cellular function and hinder the healing process, often resulting in significant skin loss. While autologous skin grafting is considered the gold standard for treating burns, its widespread use is limited due to donor site morbidity and the requirement for large amounts of tissue. Traditional wound dressings and treatments often fail to ensure complete recovery. Being initially FDA-approved to treat multiple sclerosis, 4-aminopyridine (4-AP) has also been shown to accelerate burn wound closure by transforming keratinocytes and fibroblasts when administered systemically. However, prolonged systemic use of 4-AP can lead to significant side effects. In this study, we aimed to repurpose 4-AP for treating skin burn wounds by delivering it topically using a laponite-gelatin gel formulation. This method allows for non-invasive and localized drug delivery on burn wound site. We evaluated the physical properties of the 4-AP gel shear thinning behavior, drug release kinetics, biocompatibility, and functional wound closure using a scratch assay. Moreover, our in vivo experiments showed that the 4-AP loaded gel accelerates wound healing by enhancing re-epithelialization and hair follicle regeneration and promoting fibroblast to myofibroblast transformation, which supports extracellular matrix remodeling after skin burns. This novel application of the 4-AP gel could offer a promising alternative to current burn wound therapies, potentially leading to improved outcomes for burn patients.

Acute respiratory distress syndrome (ARDS) is the most severe manifestation of acute lung injury (ALI), characterized by diffuse pulmonary inflammation, impaired gas exchange, and high morbidity and mortality. Despite its clinical significance, no specific or effective pharmacological therapies are currently available for its treatment. In this study, we developed a lung -targeted mRNA-sulfonium lipid nanoparticle (mRNA/sLNP) delivery system for the treatment of ALI in a mouse model. We first optimized sulfonium lipid structures, and the optimized sLNP was comprehensively characterized and subsequently loaded with interleukin-10 (IL-10) mRNA. In a lipopolysaccharide (LPS)-induced ALI mousemodel, IL-10/sLNPdemonstrated both prophylactic and therapeutic efficacy, significantly attenuating pulmonary and systemic inflammation, restoring barrier integrity, and reducing tissue injury.

Oral colonic drug delivery systems (CDDSs) are oftentimes associated with a short duration of action and poor tissue specificity. To address these challenges, we engineered an oral prodrug that leverages the engraftment and semi-permanence of gut commensals to create a long-acting colonic drug depot. We show that two synthetic stem peptide probes can be stereoselectively incorporated onto the surface of gut bacteria in C57BL/6 mice following oral administration. We then show that a prodrug consisting of budesonide, a corticosteroid with otherwise limiting side effects used to treat ulcerative colitis (UC), conjugated to one of these probes via a hydrolyzable ester is significantly less bioactive and is cleaved over a period of days to weeks in simulated physiological fluids. This prodrug can be integrated into the bacterial peptidoglycan in vitro and be cleaved into free budesonide over time, thereby improving drug localization and potentially rendering it safer for longer-term use. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/632432v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@2fa797org.highwire.dtl.DTLVardef@a3b5e2org.highwire.dtl.DTLVardef@1fa11fdorg.highwire.dtl.DTLVardef@b316c7_HPS_FORMAT_FIGEXP M_FIG C_FIG SIGNIFICANCECorticosteroids are highly effective anti-inflammatory drugs used in the treatment of a variety of conditions. Unfortunately, long-term corticosteroid ingestion can lead to a host of dangerous and undesirable side effects including osteoporosis, glaucoma, and a higher risk of infection, among others. Topical corticosteroids delivered via inhalation (chiefly, budesonide and fluticasone) are the primary long-term treatment modality for chronic asthma symptoms. In contrast to oral corticosteroids, they are considered safer for long-term use when given in moderation because they are directly applied to the airways and exhibit low systemic bioavailability. We sought to apply this successful paradigm to another autoimmune-related disease, ulcerative colitis (UC). We developed a drug delivery system that combines the weakly targeting method of ingestion with a highly specific parameter, microbe prevalence along the gastrointestinal tract, to help improve the specificity and colonic retention of the corticosteroid budesonide, which is currently limited to being used as a short-term treatment for moderate-to-severe UC. Our approach utilizes a largely inert prodrug that can be incorporated into the peptidoglycan of commensal bacteria found at high densities in the colon. After tethering to the bacterial surface via a synthetic stem peptide, the prodrug passively hydrolyzes (cleaves) to release the active, unadulterated form of the drug into the local area, whereas prodrug that traffics elsewhere has a higher chance of being cleared from the body before cleavage. In this manner, we can achieve targeted immunosuppression and sustained release, rendering corticosteroids, and potentially other small molecules, safer for longer term use in treating patients with UC.

Activation of the stimulator of interferon genes (STING) pathway through cyclic dinucleotides (CDNs) has been explored extensively as potent vaccine adjuvants against infectious diseases as well as to increase tumor immunogenicity towards cancer immunotherapy in solid tumors. Over the last decade, a myriad of synthetic vehicles, including liposomes, polymers, and other nanoparticle platforms, have been developed to improve the bioavailability and therapeutic efficacy of STING agonists in preclinical mouse models. In comparison to synthetic materials, protein-based carriers represent an attractive delivery platform owing to their biocompatibility, amenability to genetic engineering, and intrinsic capacity to form well-defined structures. In the present work, we have engineered the immune adaptor STING as a protein-based delivery system for efficient encapsulation and intracellular delivery of CDNs. Through genetic fusion with a protein transduction domain, the recombinant STING can spontaneously penetrate cells to markedly enhance the delivery of CDNs in a mouse vaccination model and a syngeneic mouse melanoma model. Moreover, motivated by recent findings that certain tumor cells can evade immune surveillance via loss of STING expression, we further unveiled that our STING platform can serve as a functional vehicle to restore the STING signaling in a panel of lung and melanoma cell lines with impaired STING expression. Taken together, our STING-based protein delivery platform may offer a unique direction towards targeting STING-silenced tumors as well as augmenting the efficacy of STING-based vaccine adjuvants.

Dysfunction of the lymphatic system following injury, disease, or cancer treatment can lead to lymphedema, a debilitating condition with no cure. Advances in targeted therapy have shown promise for treating diseases where conventional therapies have been ineffective and lymphatic vessels have recently emerged as a new therapeutic target. Lipid nanoparticles (LNPs) have emerged as a promising strategy for tissue specific delivery of nucleic acids. Currently, there are no approaches to target LNPs to lymphatic endothelial cells, although it is well established that intradermal (ID) injection of nanoparticles will drain to lymphatics with remarkable efficiency. To design an LNP that would effectively deliver mRNA to LEC after ID delivery, we screened a library of 150 LNPs loaded with a reporter mRNA, for both self-assembly and delivery in vivo to lymphatic endothelial cells (LECs). We identified and validated several LNP formulations optimized for high LEC uptake when administered ID and compared their efficacy for delivery of functional mRNA with that of free mRNA and mRNA delivered with a commercially available MC3-based LNP (Onpattro). The lead LEC-specific LNP was then loaded with VEGFC mRNA to test the therapeutic advantage of the LEC-specific LNP (namely, LNP7) for treating a mouse tail lymphatic injury model. A single dose of VEGFC mRNA delivered via LNP7 resulted in enhanced LEC proliferation at the site of injury, and an increase in lymphatic function up to 14-days post-surgery. Our results suggest a therapeutic potential of VEGFC mRNA lymphatic-specific targeted delivery in alleviating lymphatic dysfunction observed during lymphatic injury and could provide a promising approach for targeted, transient lymphangiogenic therapy. One Sentence SummaryDevelopment of a novel lymphatic endothelial cell-targeting lipid nanoparticle via in vivo screening for mRNA delivery improves lymphatic regeneration and function after injury.