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Understanding the complexity of the long-lived HIV reservoir during antiretroviral therapy (ART) remains a major impediment for HIV cure research. To address this, we developed single-cell viral ASAPseq to precisely define the unperturbed peripheral blood HIV-infected memory CD4+ T cell reservoir from antiretroviral treated people living with HIV (ART-PLWH) via the presence of integrated accessible proviral DNA in concert with epigenetic and cell surface protein profiling. We identified profound reservoir heterogeneity within and between ART-PLWH, characterized by novel and known surface markers within total and individual memory CD4+ T cell subsets. We further uncovered novel epigenetic profiles and transcription factor motifs enriched in HIV-infected cells that suggest infected cells with accessible provirus, irrespective of reservoir distribution, are poised for reactivation during ART treatment. Together, our findings reveal the extensive inter- and intrapersonal cellular heterogeneity of the HIV reservoir, and establish an initial multiomic atlas to develop targeted reservoir elimination strategies.

Pompe disease (PD) is a severe neuromuscular disorder caused by deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA). PD is currently treated with enzyme replacement therapy (ERT) with intravenous infusions of recombinant human GAA (rhGAA). Although the introduction of ERT represents a breakthrough in the management of PD, the approach suffers from several shortcomings. Here, we developed a mouse model of PD to compare the efficacy of hepatic gene transfer with adeno-associated virus (AAV) vectors expressing secretable GAA with long-term ERT. Liver expression of GAA results in enhanced pharmacokinetics and uptake of the enzyme in peripheral tissues compared to ERT. Combination of gene transfer with pharmacological chaperones boosts GAA bioavailability, resulting in improved rescue of the PD phenotype. Scale-up of hepatic gene transfer to non-human primates also successfully results in enzyme secretion in blood and uptake in key target tissues, supporting the ongoing clinical translation of the approach., Pompe disease is currently treated with enzyme replacement therapy (ERT) with recombinant human acid alpha-glucosidase (GAA). Here, the authors show hepatic-directed gene therapy with AAV vectors enhances GAA bioavailability compared with ERT, resulting in improved rescue of the disease phenotype in mice and broad enzyme distribution in mice and non-human primates.

Hemophilia A, a bleeding disorder, affects 1:5,000 males and is caused by deficient human blood coagulation factor VIII (hFVIII). Studies in mice and macaques identified AAVhu37.E03.TTR.hFVIIIco-SQ.PA75 as a clinical candidate gene therapy vector to treat hemophilia A. Here, we sought to determine the minimally effective dose of this vector in a hemophilia A mouse model. Mice received one of four vector doses (3x1011 - 1x1013 GC/kg) via intravenous tail vein injection; one cohort received vehicle as a control. Animals were monitored daily after vector/vehicle administration. Blood samples were collected to evaluate hFVIII activity levels and anti-hFVIII antibodies. Animals were sacrificed and necropsied on days 28 and 56; tissues were harvested for histopathological examination and blood was collected for a serum chemistry panel. We found no significant differences in liver transaminases in mice administered any vector dose compared to mice administered vehicle (except for one group administered 3x1011 GC/kg). Total bilirubin levels were significantly elevated compared to the vehicle group following two vector doses at day 56 (1x1012 and 1x1013 GC/kg). We observed no vector-related gross or histological findings. Most microscopic findings were in the vehicle group and considered secondary to blood loss, an expected phenotype of this mouse model. Since we observed no dose-limiting safety markers, we determined the maximally tolerated dose was greater than or equal to the highest dose tested (1x1013 GC/kg). Since we detected hFVIII activity in all cohorts administered vector, we conclude the minimally effective dose is 3x1011 GC/kg-the lowest dose evaluated in this study.

Wilson disease (WD), an autosomal recessive disease caused by mutations in a copper-transporting P-type ATPase (Atp7b), causes severe liver damage. This disease is currently treated with the lifelong use of copper chelation therapy, which has side effects and does not fix copper metabolism. Here, we thoroughly characterized a mouse model of WD, the toxic milk mouse, and used the model to test a gene therapy approach for treating WD. WD mice accumulated copper in the liver from birth; severe copper accumulation and concurrent liver disease were evident by 2 months of age. Intravenously administering an adeno-associated viral (AAV) 8 vector expressing a codon-optimized version of the human ATP7B transgene into 2-month-old WD mice significantly decreased liver copper levels compared with age-matched, uninjected, WD mice. We also observed a significant dose-dependent decrease in liver disease. Male mice injected with 1011 genome copies of AAV8 vector showed only mild histopathological findings with a complete lack of liver fibrosis. Therefore, we conclude that administering gene therapy at the early stages of disease onset is a promising approach for reducing liver damage and correcting copper metabolism in WD.

Adeno-associated viral (AAV) vectors can target the liver, making them an attractive platform for gene therapy approaches that require the correction of hepatocytes. Crigler-Najjar syndrome is an autosomal recessive disorder of bilirubin metabolism that occurs when the liver's uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1) enzyme activity is partially or completely absent. This syndrome is characterized by elevated bilirubin levels in the blood. An AAV8 vector was developed expressing a codon-optimized human version of UGT1A1 from a liver-specific promoter. High doses of the vector rescued neonatal lethality in newborn UGT1 knockout (KO) mice, which serve as a model of Crigler-Najjar syndrome, and significantly increased survival from 5 to 270 days. Newborn UGT1 KO mice treated with AAV had serum total bilirubin levels that were 5.7 times higher than the levels seen in heterozygous and wild-type mice, likely due to dilution of vector genome copies (GC) in the liver resulting from a proliferation of hepatocytes during growth of the animal. The elevation in serum total bilirubin levels in adult UGT1 KO mice depended on the AAV8 vector dose. At doses10

Hemophilia A is a common hereditary bleeding disorder that is characterized by a deficiency of human blood coagulation factor VIII (hFVIII). Previous studies with adeno-associated viral (AAV) vectors identified two liver-specific promoter and enhancer combinations (E03.TTR and E12.A1AT) that drove high level expression of a codon-optimized, B-domain-deleted hFVIII transgene in a mouse model of the disease. This study further evaluated these enhancer/promoter combinations in cynomolgus macaques using two different AAV capsids (AAVrh10 and AAVhu37). Each of the four vector combinations was administered intravenously at a dose of 1.2 × 10

Argininosuccinic aciduria (ASA) is the second most common genetic disorder affecting the urea cycle. The disease is caused by deleterious mutations in the gene encoding argininosuccinate lyase (ASL); total loss of ASL activity results in severe neonatal onset of the disease, which is characterized by hyperammonemia within a few days of birth that can rapidly progress to coma and death. The long-term complications of ASA, such as hypertension and neurocognitive deficits, appear to be resistant to the current treatment options of dietary restriction, arginine supplementation, and nitrogen scavenging drugs. Treatment-resistant disease is currently being managed by orthotopic liver transplant, which shows variable improvement and requires lifetime immunosuppression. Here, we developed a gene therapy strategy for ASA aimed at alleviating the symptoms associated with urea cycle disruption by providing stable expression of ASL protein in the liver. We designed a codon-optimized human ASL gene packaged within adeno-associated virus serotype 8 (AAV8) as a vector for targeted delivery to the liver. To evaluate the therapeutic efficacy of this approach, we utilized a murine hypomorphic model of ASA. Neonatal administration of AAV8 via the temporal facial vein extended survival in ASA hypomorphic mice, although not to wild-type levels. Intravenous injection into adolescent hypomorphic mice led to increased survival and body weight and correction of metabolites associated with the disease. Our results demonstrate that AAV8 gene therapy is a viable approach for the treatment of ASA.

Systemically delivered adeno-associated viral (AAV) vectors are now in early-phase clinical trials for a variety of diseases. While there is a general consensus on inclusion and exclusion criteria for each of these trials, the conditions under which vectors are infused vary significantly. In this study, we evaluated the impact of intravenous infusion rate of AAV8 vector in cynomolgus macaques on transgene expression, vector clearance from the circulation, and potential activation of the innate immune system. The dose of AAV8 vector in terms of genome copies per kilogram body weight and its concentration were fixed, while the rate of infusion varied to deliver the entire dose over different time periods, including 1, 10, or 90 minutes. Analyses during the in-life phase of the experiment included sequential evaluation of whole blood for vector genomes and appearance of proinflammatory cytokines. Liver tissues were analyzed at the time of necropsy for enhanced green fluorescent protein (eGFP) expression and vector genomes. The data were remarkable with a relative absence of any statistically significant effect of infusion time on vector transduction, safety, and clearance. However, some interesting and unexpected trends did emerge.