Single-Cell RNA Sequencing Reveals Heterogeneity Among Adult Mouse, Primate and Human Kidney Cells

Multiple studies have been performed to map the kidney landscape of human and rodent, along with the development of sequencing technique. Although rodent disease models have been widely applied, many disadvantages also exist. Non-human primates (NHPs) are considered as the closest experimental animals to humans and show great advantages in the construction of animal models of human disease. Therefore, a comprehensive understanding of the heterogeneity and homogeneity between human and multiple animal kidney cells is important for further establishing animal models of human renal disease. Here, we generated the first single-cell transcriptome data of normal adult cynomolgus monkey kidney using 10x Genomics scRNA-seq platform. Then, we further performed an in-depth comparison across species at the single-cell level, and our analysis indicated that the gene expression of adult primate kidney cells showed a better correlation with human kidney than mouse kidney. Furthermore, our results demonstrated that the cellular localization of GWAS-identified renal disease genes showed differences across species. The cellular localization of blood pressure associated genes in human displayed similarity to cynomolgus monkey. This study provided a reliable reference for further studies associated with renal diseases on NHPs. In addition, our results also provided a novel insight into the choice of renal disease animal model and a detailed explanation for close genetic relationship between NHPs and human at a single cell level.

Generation of in situ CRISPR-mediated primary and metastatic cancer from monkey liver

Non-human primates (NHPs) represent the most valuable animals for drug discovery. However, the current main challenge remains that the NHP has not yet been used to develop an efficient translational medicine platform simulating human diseases, such as cancer. This study generated an in situ gene-editing approach to induce efficient loss-of-function mutations of Pten and p53 genes for rapid modeling primary and metastatic liver tumors using the CRISPR/Cas9 in the adult cynomolgus monkey. Under ultrasound guidance, the CRISPR/Cas9 was injected into the cynomolgus monkey liver through the intrahepatic portal vein. The results showed that the ultrasound-guided CRISPR/Cas9 resulted in indels of the Pten and p53 genes in seven out of eight monkeys. The best mutation efficiencies for Pten and p53 were up to 74.71% and 74.68%, respectively. Furthermore, the morbidity of primary and extensively metastatic (lung, spleen, lymph nodes) hepatoma in CRISPR-treated monkeys was 87.5%. The ultrasound-guided CRISPR system could have great potential to successfully pursue the desired target genes, thereby reducing possible side effects associated with hitting non-specific off-target genes, and significantly increasing more efficiency as well as higher specificity of in situ gene editing in vivo, which holds promise as a powerful, yet feasible tool, to edit disease genes to build corresponding human disease models in adult NHPs and to greatly accelerate the discovery of new drugs and save economic costs.

Treating Iron Overload Disorders with a Novel Therapeutic Antibody Targeting TMPRSS6

Iron is an essential element for almost all living organisms as it participates in a wide variety of metabolic processes. Disorders of iron metabolism are among the most prevalent human diseases, ranging from anemia to hemochromatosis. Excessive iron accumulations in major organs of iron overload patients can lead to high mortality. Hepcidin, a HAMP-encoded liver hormone, is the master regulator of iron homeostasis. By binding to the sole iron exporter ferroportin and causing internalization and degradation of the complex, hepcidin inhibits cellular iron efflux, thereby lowers plasma iron levels. Inappropriately suppressed/low hepcidin production is central to iron overload. Transmembrane protease serine-6 (TMPRSS6), a type II transmembrane serine protease primarily expressed in liver, downregulates hepcidin expression through BMP-SMAD pathway. TMPRSS6 deficiencies have been shown to cause hepcidin overexpression in both TMPRSS6-mutant mice and in patients with iron-refractory iron deficiency anemia (IRIDA). Therefore, TMPRSS6 is a viable therapeutic target for iron overload disorders. Here we report the generation of an anti-TMPRSS6 antibody through a hybridoma campaign using a DNA-based immunization approach, followed by humanization and sequence optimization. Lead antibody, hzMWTx-003 selectively binds human TMPRSS6 with low nanomolar affinity (KD: 7.6nM), and is cross-reactive to rodent (mouse and rat) and monkey (cynomolgus and rhesus) TMPRSS6. Single-dose injection of hzMWTx-003 was able to significantly elevate serum hepcidin and liver HAMP RNA levels in wildtype mice, resulting in significantly reduced serum iron level. The Hbb th3/+ mouse model of β-thalassemia, like its human counterpart, is characterized by iron overload, ineffective erythropoiesis and splenomegaly. Treatment of Hbb th3/+mice with MWTx-003 effectively increased hepcidin expression at both protein and RNA levels, leading to significantly reduced serum iron and liver non-heme iron content. MWTx-003 also dramatically improved anemia and ineffective erythropoiesis, and alleviated splenomegaly in these mice. CMC development of hzMWTx-003 confirms outstanding biophysical properties. Preliminary studies in cynomolgus monkey using GLP-grade material demonstrated good pharmacokinetics of hzMWTx-003 and expected pharmacodynamic response where reduction of serum iron could be sustained for 21 days after single dose administration. A single dose toxicology study in cynomolgus monkey revealed no safety concerns, and no production of anti-idiotype antibodies was detected. In summary, anti-TMPRSS6 antibody MWTx-003 represents a promising therapy for iron overload disorders such as β-thalassemia, and potentially other diseases where iron restriction is beneficial. Disclosures Chen: Mabwell Therapeutics Inc: Current Employment. Wang: Mabwell Therapeutics Inc: Current Employment. Zheng: Mabwell (Shanghai) Bioscience Co. Ltd: Current Employment. Huang: Mabwell Therapeutics Inc: Current Employment. Mao: Mabwell (Shanghai) Bioscience Co. Ltd.: Current Employment. Ouyang: Mabwell (Shanghai) Bioscience Co. Ltd.: Current Employment. Du: Mabwell Therapeutics Inc: Current Employment.

711 IGM-7354 is an anti-PD-L1 IgM antibody and IL-15 cytokine fusion that enhances NK and CD8+ T cell proliferation and tumor cytotoxicity plus potently reverses T cell exhaustion

BackgroundWhile approved PD-1/PD-L1 inhibitory antibodies have demonstrated clinical efficacy in certain cancer patients, relapse following a primary response is often observed. Enhancing anti-tumor immune responses with an immunostimulatory cytokine, IL-15 is an attractive combination strategy to enhance anti-tumor NK and memory CD8+ T cell expansion and survival. We have developed IGM-7354, a high affinity, high avidity anti-PD-L1 pentameric IgM antibody with an IL-15Rα chain and IL-15 fused to the joining (J) chain, designed to deliver IL-15 to PD-L1 expressing tumors for enhancing anti-tumor immune responses.MethodsIGM-7354 was generated by grafting heavy chain variable regions of a high affinity humanized anti-PD-L1 IgG onto the IgM heavy chain framework, co-expressed with the light chain and the J chain which included a single IL-15Rα and IL-15 fusion. Binding ELISAs were performed using recombinant antigens. Human and cynomolgus monkey PBMCs were used for potency testing. Reversal of T cell exhaustion was tested using in vitro MLR. In vitro cytotoxicity assays were performed with luciferase-tagged MDA-MB-231 cells and PBMCs. In vivo pharmacodynamic studies were conducted in mice and cynomolgus monkeys.ResultsIGM-7354 bound human and cynomolgus monkey PD-L1 with the same affinity but did not bind to rat or mouse PD-L1. In addition, the IL-15 component of IGM-7354 bound to human and cynomolgus β chain of the trimeric IL-15 receptor with similar affinities, but with weaker binding affinity to rodent IL-15Rβ. Using in vitro assays with PBMCs, IGM-7354 dose dependently enhanced the proliferation of human and cynomolgus monkey NK and CD8+ T cells. Furthermore, IGM-7354 was able to reverse T cell exhaustion in an in vitro MLR beyond that of an IL-15/IL15Rα complex or anti-PD-L1 IgM or IgG alone, as demonstrated by an increase in activation and effector cytokine secretion. IGM-7354 also enhanced in vitro killing of PD-L1-expressing MDA-MB-231 breast cancer cells by human PBMCs. Pharmacodynamic studies in an MDA-MB-231 xenograft mouse model showed dose-dependent increases in circulating NK and CD8+ T cells and tumor infiltrating lymphocytes, which correlated with tumor regression. In cynomolgus monkeys, intravenous administration of IGM-7354 was well tolerated and dose dependently induced the proliferation of NK and CD8+ T cells.ConclusionsIGM-7354 stimulates NK and CD8+ T cell expansion in vitro and in vivo plus induces tumor regressions in mouse tumor models. This approach may enhance tumor localization of the immunostimulatory cytokine IL-15 through high affinity and high avidity binding to PD-L1 thereby improving anti-tumor responses and minimizing toxicity.Ethics ApprovalAll animal studies were conducted according to approved Institutional Animal Care and Use Committee (IACUC) protocols of the testing facilities.

Surgical removal of a telemetry system in a cynomolgus monkey (Macaca fascicularis): a 12-month observation study

Background Telemetry is a wireless implanted device that measures biological signals in conscious animals and usually requires surgery for its removal when the study is finished. After removing the device, the animals are either used for other studies or euthanatized. Case presentation Herein, we report the case of a living cynomolgus monkey (Macaca fascicularis) that was used for the entire experimental period, instead of euthanasia, after surgical removal of an implanted telemetry system. Radiography was used to determine the status of the implanted telemetry, following which, a repair surgery was performed for removing the system; clinical signs were used to preserve the life of the cynomolgus monkey. Postoperative clinical signs, food consumption, hematology, and serum biochemistry were examined during the 12-month observational period. No abnormal readings or conditions were observed in the subject after implant removal. Conclusions This study may be a useful case report for living cynomolgus monkeys in telemetry implantations used throughout the study period. We suggest minimizing the suffering and improving the welfare of these animals.

COVID-19 cynomolgus macaque model reflecting human COVID-19 pathological conditions

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global threat to human health and life. A useful pathological animal model accurately reflecting human pathology is needed to overcome the COVID-19 crisis. In the present study, COVID-19 cynomolgus monkey models including monkeys with underlying diseases causing severe pathogenicity such as metabolic disease and elderly monkeys were examined. Cynomolgus macaques with various clinical conditions were intranasally and/or intratracheally inoculated with SARS-CoV-2. Infection with SARS-CoV-2 was found in mucosal swab samples, and a higher level and longer period of viral RNA was detected in elderly monkeys than in young monkeys. Pneumonia was confirmed in all of the monkeys by computed tomography images. When monkeys were readministrated SARS-CoV-2 at 56 d or later after initial infection all of the animals showed inflammatory responses without virus detection in swab samples. Surprisingly, in elderly monkeys reinfection showed transient severe pneumonia with increased levels of various serum cytokines and chemokines compared with those in primary infection. The results of this study indicated that the COVID-19 cynomolgus monkey model reflects the pathophysiology of humans and would be useful for elucidating the pathophysiology and developing therapeutic agents and vaccines.