Citations

Abstract Orthoebolaviruses, including Ebola virus (EBOV) and Bundibugyo virus (BDBV), cause sporadic outbreaks and devastating hemorrhagic infections in humans. A significant challenge that impedes the study of filoviruses is that the infectious virus can only be handled in biosafety level 4 (BSL4) facilities due to their extreme virulence. Life cycle modeling systems that use minigenomes and transcription/replication-competent virus-like particles (trVLPs) are powerful tools for studying these virus’ biology and to explore antiviral therapies under BSL2 conditions. To date, these powerful tools have only been utilized in vitro in cell culture systems. In this work, we demonstrate the use of EBOV trVLPs in vivo. We report the fine specificity of first infection events in a model of EBOV injection in the skin. Cre recombinase expressing monocistronic EBOV trVLPs were packaged and used to inject Cre reporter mice intradermally (ID). Initial infection events were monitored in living animals by luciferase imaging and then by flow cytometry to track cell-specific expression of Cre-activated GFP. By this approach, EBOV trVLPs were shown to directly infect T cells, monocytes, dendritic cells (DCs) with notably high first infections of skin-resident Langerhans cells (LCs) in the skin barrier and its draining lymph node. EBOV trVLPs were next tested as an in vivo tool to assess antiviral therapies by testing the ability of an EBOV vaccine to reduce trVLP luciferase levels after infection in the skin. This work demonstrates first in vivo use of EBOV trVLPs and provides proof of concept for their use as an in vivo BSL2 model to more rapidly develop antiviral agents and vaccines.

Background/Objectives: Antigen presenting cells (APCs) and immune cells have unique properties to drive or suppress immune responses. They are therefore key targets for the expression of vaccine antigens or transgene proteins. To better determine the utility of different molecular therapies to modify these cells, mRNA and DNA-based molecular therapy vectors were compared for their ability to genetically modify immune cells after intradermal injections in mice. DNA-based vectors included naked plasmid DNA, plasmid packaged in lipid nanoparticles (LNPs), and replication-defective adenovirus (Ad) vectors. mRNA delivery was mediated by packaging into LNPs like those used in COVID-19 vaccines. Methods: Each vector was used to deliver Cre recombinase into Cre reporter mice whose cells were activated to express green fluorescent protein (GFP) and firefly luciferase after Cre recombination. The mice were injected intradermally (ID) near the base of their tail at a site that drains into the inguinal lymph node. Luciferase activity was imaged in the living mice 1 or 4 days after vector injection. The animals were then euthanized, and luciferase activity was imaged in the draining inguinal lymph node. Cells were prepared from the intradermal injection site and from the draining lymph node to determine which immune cells were genetically modified by phenotyping CD45, CD3, and CD11b GFP-positive cells by flow cytometry. Given that the skin uniquely contains Langerhans dendritic cells, these CD207+ cells were also phenotyped in skin samples and in the draining lymph node. Results: In both the skin and in the draining lymph node, the rank order of luciferase and GFP activation by the vectors were: (1) Ad; (2) mRNA-LNP; (3) DNA-LNP; and (4) naked DNA. Only mRNA-LNP and Ad vectors mediated obvious luciferase activity in the living animals and in the draining lymph nodes by imaging. Notably, both vectors appeared to leak from the ID injection site and not only modify the draining lymph node but also strongly modify the livers of the mice. Naked DNA and DNA-LNP mediated detectable GFP activation in the skin and draining lymph node in some mice, but this activity was low and did not reach statistical significance when compared to PBS-treated animals. mRNA-LNPs and Ad both mediated significant Cre delivery in CD45+, CD3+, CD11b+, and CD207+ immune cells in the skin and in the lymph node, with adenovirus mediating consistently higher levels of expression in all of the tested cells. Conclusions: These data indicate that mRNA-LNP and Ad vectors mediate stronger modification of skin and lymph node immune cells after intradermal injections. Naked DNA and DNA-LNPs were markedly less potent at this activity than the other vectors. These data are consistent with the higher vaccine potency of mRNA-LNP and Ad vectors and suggest that approaches that increase targeting of immune cell subsets may have utility to increase efficacy while also reducing off-target modification of tissues like the liver.

Abstract Alport syndrome is caused by mutations in the type IV collagen genes COL4A3, COL4A4, and COL4A5 which are expressed in podocytes in the glomerulus of the kidney. Mutation of these genes disrupts blood filtration by the kidney leading to proteinuria and kidney failure. There is no cure for Alport Syndrome. Current therapies do not treat the genetic cause of the disease, but instead aim to delay the disease by reducing blood pressure in the kidney. Here we tested the ability of mRNA therapy to treat the disease. Mice with X-linked Alport syndrome (XLAS) due to mutation of Col4A5 were treated intravenously with lipid nanoparticles (LNPs) carrying three mRNAs encoding COL4A3, COL4A4, and COL4A5 to produce trimeric collagen IV repair proteins. This intravenous mRNA therapy significantly reduced proteinuria and blood urea nitrogen. Protection against the syndrome was maintained provided that LNP-mRNA injections were continued. However, efficacy was lost when therapy was terminated. These data provide proof of principle to apply a genetic mRNA therapy to halt progression of Alport syndrome in a mouse model of XLAS. These data also demonstrate that damage to the kidney filtration barrier can be leveraged to deliver large molecular therapies to podocytes and other cells within the kidney to treat Alport syndrome and other kidney genetic diseases.

Uncontrolled systemic inflammatory responses are a critical pathological feature of fatal Ebola virus (EBOV) infection. While some inflammatory responses may originate from mononuclear phagocytes (MNPs), nonimmune cells vastly outnumber MNPs and may be an important source of inflammation. Here, we demonstrated that highly virulent EBOV induced a high and sustained pro-inflammatory response compared to less virulent ebolaviruses in non-MNPs through TLR4-independent NF-κB activation. We identified the EBOV matrix protein VP40 as a potent activator of NF-κB in non-MNPs, whose intrinsic inflammatory activation ability is higher than VP40 proteins from less virulent ebolaviruses. This suggests that VP40 is a virulence determinant inducing distinct degrees of pro-inflammatory responses among ebolaviruses. Mechanistically, VP40 activated the NF-κB signaling pathway, primarily via TNFR1 using a ligand-independent mechanism. These findings reveal mechanisms that may drive systemic inflammation and promote EBOV pathogenesis, suggesting potential therapeutic strategies to mitigate immune dysregulation in severe EBOV infections.

Background: Adeno-associated viruses (AAVs) are widely used vectors for in vivo gene therapy, but their standard storage at −80 °C limits deployment in regions lacking ultracold infrastructure. Strategies enabling stable AAV storage at higher temperatures are needed to support global distribution. Methods: Nine AAV serotypes were lyophilized in simple sucrose-based buffers. Post-lyophilization vector integrity was assessed by measuring in vitro transduction efficiency using a luciferase reporter in cell-based assays. Stability of selected serotypes (AAV2.5 and AAV6) was further evaluated over 8 weeks under varying storage temperatures. Results: Lyophilization in sucrose preserved transduction activity for all tested serotypes (AAV1, AAV2, AAV2.5, AAV3, AAV4, AAV5, AAV6, AAV8, AAV9, and AAVrh10). Notably, AAV2, AAV2.5, and AAV6 exhibited 3- to 6-fold increases in transduction, an effect attributable to the sucrose excipient rather than the lyophilization process itself. Long-term stability of lyophilized vectors varied by serotype, temperature, and vial-seal integrity. AAV6 retained full activity for at least 8 weeks when stored at 4 °C or −20 °C. Conclusions: AAV vectors can be effectively lyophilized in simple sucrose solutions, enabling storage at standard −20 °C freezer temperatures while maintaining functional activity. Optimization of lyophilization buffers and excipients may further extend AAV stability at higher temperatures, improving feasibility for global gene therapy deployment.

Autosomal dominant polycystic kidney disease is the most common inherited kidney disorder and a leading monogenic cause of kidney failure. Reduction or loss of polycystin-1 and polycystin-2 function disrupts ciliary calcium signaling, elevates cyclic AMP (cAMP), reprograms cellular metabolism, and activates proliferative cascades that drive cyst expansion. Tolvaptan, a vasopressin V2 receptor antagonist, established cAMP modulation as a disease-modifying strategy but is limited by aquaretic effects and hepatotoxicity risk. This review highlights emerging therapeutic strategies in clinical trial development that extend beyond vasopressin antagonism. Gene-directed therapies aim to restore polycystin dosage, including anti–miR-17 oligonucleotides ( e.g ., farabursen) and pharmacochaperones that rescue misfolded polycystin-1 and restore trafficking in select PKD1 missense variants ( e.g ., VX-407). Paracrine signaling can be modulated with anti–pregnancy-associated plasma protein A antibodies that reduce insulin-like growth factor-1 bioavailability in cystic microenvironments. Metabolic reprogramming is targeted by agents such as metformin, bempedoic acid, glucagon-like peptide-1 receptor agonists, and structured dietary interventions. Sodium-glucose cotransporter 2 inhibitors hold theoretical promise but await definitive results from ongoing trials. A novel cAMP-lowering strategy through phosphodiesterase-4 activation is advancing toward clinical testing. Looking ahead, gene therapy, and genome editing offer the potential to raise polycystin levels above the threshold for cystogenesis, although challenges in vector capacity, kidney-specific delivery, and durability remain. Artificial intelligence–guided discovery, coupled with human organoid platforms, is accelerating therapeutic repurposing and rational combination design. Collectively, these advances signal a transition toward a layered, mechanism-guided framework in which vasopressin blockade is integrated with metabolic, other signaling, and genotype-specific therapies. As biomarkers and risk stratification tools mature, autosomal dominant polycystic kidney disease management is poised to become increasingly precise, tolerable, and effective.

ABSTRACT Thogotoviruses are arthropod-borne viruses belonging to the genus Thogotovirus within the family Orthomyxoviridae . Like other orthomyxoviruses, such as the influenza A viruses (IAV), thogotoviruses replicate in the nucleus. As a result, progeny viral ribonucleoprotein complexes (vRNPs) must be exported to the cytoplasm prior to virion assembly and budding at the plasma membrane. In IAV, this export depends on binding of the viral nuclear export protein (NEP) to the cellular exportin chromosomal maintenance 1 (CRM1). In contrast, the mechanism of vRNP nuclear export, including identification of a protein with NEP functionality, has not been characterized for any thogotoviruses. Here, we characterized vRNP nuclear export in Dhori virus (DHOV), a prototypic member of the Thogotovirus genus. DHOV replication and nuclear export of the viral nucleoprotein were inhibited by the canonical CRM1 inhibitor leptomycin B (LMB), suggesting that DHOV vRNP export also utilizes CRM1. Interestingly, LMB treatment led to nuclear retention of the DHOV matrix (M) protein in both infected and transfected cells. Using a mammalian two-hybrid system, we found that DHOV M interacts with CRM1 through a nuclear export sequence (NES) located between amino acids 111 and 128. Mutation of hydrophobic residues within this NES reduced M-CRM1 interaction, abolished the NES phenotype when fused to a fluorescent protein, and impaired rescue of recombinant DHOV by reverse genetics. Together, our results reveal that DHOV vRNP nuclear export is CRM1-dependent and mediated by the M protein rather than a dedicated NEP-like protein, providing the first mechanistic insight into vRNP egress in the genus Thogotovirus . IMPORTANCE Dhori virus (DHOV) is a pathogenic tick-borne virus in the genus Thogotovirus , in the family Orthomyxoviridae. Despite evidence of DHOV exposure in various mammals, including humans, its basic biology is not well understood. We investigated how DHOV’s progeny genome and protein complexes—viral ribonucleoprotein complexes (vRNPs)—are transported out of the nucleus. Our findings show that DHOV, like the influenza viruses, uses the cellular protein chromosomal maintenance protein 1 (CRM1) for vRNP export. We found that chemically inhibiting CRM1 completely blocked DHOV vRNP export, preventing the production of progeny viruses from infected cells. Screening of all known DHOV proteins revealed that the matrix protein, which forms the virus’ scaffold, interacted with CRM1, suggesting it may link CRM1 to the vRNPs. These results advance our understanding of DHOV replication and suggest that chemically inhibiting vRNP export could be a way to treat thogotovirus infections.

Abstract Description Therapeutic in situ chimeric antigen receptor (isCAR) T cells can be generated by targeting activated T cells within a lymph node (LN) with retroviruses encoding CARs. While isCAR T cells are successfully generated by intradermal LN priming using adenovirus encoding allogeneic MHC in all mouse lines tested, differences in emerging therapeutic peripheral isCAR T cells are found in a strain dependent manner. Potentially harmful off target retroviral transduction of B cells with CARs is observed within the targeted LN. Here we report the blockade of B cell transduction using anti-CD20 antibody B cell depletion with the introduction of anti-CD19 chimeric antigen receptors into the activated CD8+ T cells. Lymphocytes were analyzed in blood and LN following isCAR T cell generation. When B cells were depleted by systemic administration of anti-CD20 antibodies during isCAR T cell induction, >97.5% systemic depletion of B cells was achieved. Whereas very small numbers of CAR transduced B cells were found in the blood of mice not treated with anti-CD20, none were observed in animals systemically depleted of B cells. In contrast, CAR B cells persisted in the LN of local anti-CD20 treated animals. However, animals expressing dominant CD8+ isCAR T cell populations eliminated LN B cells expressing CARs by week two. Furthermore, systemic treatment of lymphoma in animals with anti-CD20 antibody complemented anti-CD19 isCAR T therapy while blocking off target B cell transduction. Funding Sources Mayo Clinic Ventures Mayo Clinic Graduate School of Biomedical Sciences Mayo Clinic Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)

Abstract Description tolerance is the “holy grail” in the fields of transplantation medicine and the treatment of autoimmune diseases. We previously reported that TIGIT+ B cells can efficiently control inflammatory responses while promoting regulatory T cell response via the ligation of CD155 expressed on both T cells and dendritic cells (DCs). Recent studies have also demonstrated that lack of TIGIT expression in B cells can lead to inflammation in the central nervous system in both humans and mice. These findings prompted us to explore whether TIGIT+ B cell therapy model could be developed for the treatment of inflammatory diseases. In this study, we report that TIGIT+ B cells can be generated with replication-incompetent recombinant Adv5 vectors designed to target CD21 on B cells. Those TIGIT+ B cells generated with our novel Adv5 vectors can efficiently control inflammatory T cell responses in vitro by directly acting on T cells and by regulating inflammatory function of DCs. The preclinical efficacy of TIGIT+ B cell therapy model and its underlying mechanisms of action are also investigated using an experimental autoimmune encephalomyelitis model. Data from this study support the clinical development of this novel TIGIT+ B cell therapy model for the treatment of inflammatory diseases. Funding Sources Mayo Clinic Cancer Center Topic Categories Therapeutic Approaches to Autoimmunity (THER)

Abstract Description Antigen receptor (CAR) T cells can be generated in vivo within the natural lymph node (LN) environment as the immune response to a virus infection unfolds. This in situ approach entails priming LNs with intradermal inoculations of replication defective adenoviruses encoding MHC class I and class II allo/xeno-antigens. Universal transplant antigens were devised for LN priming by introducing tryptophan into amino acid position 162 of the MHC HLA-A2:01 class I heavy chain and by using the mouse MHC class II beta chain to form chimeric class II antigens with endogenous class II alleles. The virus encoded mismatched MHC antigen presenting molecules are expressed functionally in the LN following intradermal inoculation provoking polyclonal T cells responses. Three days later CAR T cells are generated by directly injecting retroviruses encoding CARs of interest into the responding LN. Mouse CD19-specifc CAR T cells created in this manner in B6-DQ8 and DQ8/A2 mice effectively target endogenous B cells and are therapeutic in male and female Emu-myc lymphomas demonstrating the potential for the generating functional CAR T cells directly in vivo. While in situ CAR T cells are readily produced in B6, B6-IA0/DQ8, B6-IA0/DQ8/A2, and B6-IA0/DQ6 LNs, functional differences among the strains emerged in the periphery suggesting that properties of the autoimmune-associated HLA DQ8 class II allele is particularly reactive during the production of CAR T cells in vivo. Funding Sources MustangBio, Inc Mayo Clinic Center of Biomedical Research Mayo Clinic Department of Immunology Mayo Clinic Graduate School of Biomedical Science Fraternal Order of Eagles Mayo Clinic Ventures NIH R21 AI 097337 NIH R01 CA 178804 NIH T32 AI 07425 Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)