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  • Analysis of structural variation among inbred mouse strains. BMC genomics Arslan, A., Fang, Z., Wang, M., Tan, Y., Cheng, Z., Chen, X., Guan, Y., J Pisani, L., Yoo, B., Bejerano, G., Peltz, G. 2023; 24 (1): 97


    BACKGROUND: 'Long read' sequencing methods have been used to identify previously uncharacterized structural variants that cause human genetic diseases. Therefore, we investigated whether long read sequencing could facilitate genetic analysis of murine models for human diseases.RESULTS: The genomes of six inbred strains (BTBR T+Itpr3tf/J, 129Sv1/J, C57BL/6/J, Balb/c/J, A/J, SJL/J) were analyzed using long read sequencing. Our results revealed that (i) Structural variants are very abundant within the genome of inbred strains (4.8 per gene) and (ii) that we cannot accurately infer whether structural variants are present using conventional short read genomic sequence data, even when nearby SNP alleles are known. The advantage of having a more complete map was demonstrated by analyzing the genomic sequence of BTBR mice. Based upon this analysis, knockin mice were generated and used to characterize a BTBR-unique 8-bp deletion within Draxin that contributes to the BTBR neuroanatomic abnormalities, which resemble human autism spectrum disorder.CONCLUSION: A more complete map of the pattern of genetic variation among inbred strains, which is produced by long read genomic sequencing of the genomes of additional inbred strains, could facilitate genetic discovery when murine models of human diseases are analyzed.

    View details for DOI 10.1186/s12864-023-09197-5

    View details for PubMedID 36864393

  • A human multi-lineage hepatic organoid model for liver fibrosis. Nature communications Guan, Y., Enejder, A., Wang, M., Fang, Z., Cui, L., Chen, S., Wang, J., Tan, Y., Wu, M., Chen, X., Johansson, P. K., Osman, I., Kunimoto, K., Russo, P., Heilshorn, S. C., Peltz, G. 2021; 12 (1): 6138


    To investigate the pathogenesis of a congenital form of hepatic fibrosis, human hepatic organoids were engineered to express the most common causative mutation for Autosomal Recessive Polycystic Kidney Disease (ARPKD). Here we show that these hepatic organoids develop the key features of ARPKD liver pathology (abnormal bile ducts and fibrosis) in only 21 days. The ARPKD mutation increases collagen abundance and thick collagen fiber production in hepatic organoids, which mirrors ARPKD liver tissue pathology. Transcriptomic and other analyses indicate that the ARPKD mutation generates cholangiocytes with increased TGFbeta pathway activation, which are actively involved stimulating myofibroblasts to form collagen fibers. There is also an expansion of collagen-producing myofibroblasts with markedly increased PDGFRB protein expression and an activated STAT3 signaling pathway. Moreover, the transcriptome of ARPKD organoid myofibroblasts resemble those present in commonly occurring forms of liver fibrosis. PDGFRB pathway involvement was confirmed by the anti-fibrotic effect observed when ARPKD organoids were treated with PDGFRB inhibitors. Besides providing insight into the pathogenesis of congenital (and possibly acquired) forms of liver fibrosis, ARPKD organoids could also be used to test the anti-fibrotic efficacy of potential anti-fibrotic therapies.

    View details for DOI 10.1038/s41467-021-26410-9

    View details for PubMedID 34686668

  • The Phosphatidylethanolamine Biosynthesis Pathway Provides a New Target for Cancer Chemotherapy. Journal of hepatology Guan, Y. n., Chen, X. n., Wu, M. n., Zhu, W. n., Arslan, A. n., Takeda, S. n., Nguyen, M. H., Majeti, R. n., Thomas, D. n., Zheng, M. n., Peltz, G. n. 2019


    Since iPSC human develop into hepatic organoids through stages that resemble human embryonic liver development, they can be used to study developmental processes and disease pathology. Therefore, we examined the early stages of hepatic organoid formation to identify key pathways affecting early liver development.Single cell RNA-sequencing and metabolomic analysis was performed on developing organoid cultures at the iPSC, hepatoblast (day 9) and mature organoid stage. The importance of the phosphatidyl-ethanolamine biosynthesis pathway to early liver development was examined in developing organoid cultures using iPSC with a CRISPR-mediated gene knockout and an over the counter medication (meclizine) that inhibits the rate-limiting enzyme in this pathway. Meclizine's effect on the growth of a human hepatocarcinoma cell line in a xenotransplantation model and on the growth of acute myeloid leukemia cells in vitro was also examined.Transcriptomic and metabolomic analysis of organoid development indicated that the phosphatidyl-ethanolamine biosynthesis pathway is essential for early liver development. Unexpectedly, early hepatoblasts were selectively sensitive to the cytotoxic effect of meclizine. We demonstrate that meclizine could be repurposed for use in a new synergistic combination therapy for primary liver cancer: a glycolysis inhibitor reprograms cancer cell metabolism to make it susceptible to the cytotoxic effect of meclizine. This combination inhibited the growth of a human liver carcinoma cell line in vitro; and in a xenotransplantation model without causing significant side effets. This drug combination was also highly active against acute myeloid leukemic cells.Our data indicates that the phosphatidyl-ethanolamine biosynthesis is a targetable pathway for cancer; and that meclizine may have clinical efficacy as a repurposed anti-cancer drug when used as part of a new combination therapy.

    View details for DOI 10.1016/j.jhep.2019.11.007

    View details for PubMedID 31760071