Browsing by Author "Clark, K. Reed"

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    Essential metabolic, anti-inflammatory, and anti-tumorigenic functions of miR-122 in liver
    (The Journal of Clinical Investigation, 2012-08-01) Hsu, Shu-hao; Wang, Bo; Kota, Janaiah; Yu, Jianhua; Costinean, Stefan; Kutay, Huban; Yu, Lianbo; Bai, Shoumei; La Perle, Krista; Chivukula, Raghu R.; Mao, Hsiaoyin; Wei, Min; Clark, K. Reed; Mendell, Jerry R.; Caligiuri, Michael A.; Jacob, Samson T.; Mendell, Joshua T.; Ghoshal, Kalpana
    miR-122, an abundant liver-specific microRNA (miRNA), regulates cholesterol metabolism and promotes hepatitis C virus (HCV) replication. Reduced miR-122 expression in hepatocellular carcinoma (HCC) correlates with metastasis and poor prognosis. Nevertheless, the consequences of sustained loss of function of miR-122 in vivo have not been determined. Here, we demonstrate that deletion of mouse Mir122 resulted in hepatosteatosis, hepatitis, and the development of tumors resembling HCC. These pathologic manifestations were associated with hyperactivity of oncogenic pathways and hepatic infiltration of inflammatory cells that produce pro-tumorigenic cytokines, including IL-6 and TNF. Moreover, delivery of miR-122 to a MYC-driven mouse model of HCC strongly inhibited tumorigenesis, further supporting the tumor suppressor activity of this miRNA. These findings reveal critical functions for miR-122 in the maintenance of liver homeostasis and have important therapeutic implications, including the potential utility of miR-122 delivery for selected patients with HCC and the need for careful monitoring of patients receiving miR-122 inhibition therapy for HCV.
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    Impaired regeneration in LGMD2A supported by increased Pax7 positive satellite cell content and muscle specific microRNA dysregulation
    (Muscle & Nerve, 2013-05) Rosales, Xiomara Q.; Malik, Vinod; Sneh, Amita; Chen, Lei; Lewis, Sarah; Kota, Janaiah; Gastier-Foster, Julie M.; Astbury, Caroline; Pyatt, Rob; Reshmi, Shalini; Rodino-Klapac, Louise R.; Clark, K. Reed; Mendell, Jerry R.; Sahenk, Zarife
    Introduction—Recent in vitro studies suggest that CAPN3 deficiency leads initially to accelerated myofiber formation followed by depletion of satellite cells (SC). In normal muscle, upregulation of miR-1 and miR-206 facilitates transition from proliferating SCs to differentiating myogenic progenitors. Methods—We examined the histopathological stages, Pax7 SC content, and muscle specific microRNA expression in biopsy specimens from well-characterized LGMD 2A patients to gain insight into disease pathogenesis. Results—Three distinct stages of pathological changes were identified that represented the continuum of the dystrophic process from prominent inflammation with necrosis and regeneration to prominent fibrosis, which correlated with age and disease duration. Pax7-positive SCs were highest in fibrotic group and correlated with down-regulation of miR-1, miR-133a, and miR-206. Conclusions—These observations, and other published reports, are consistent with microRNA dysregulation leading to inability of Pax7-positive SCs to transit from proliferation to differentiation. This results in impaired regeneration and fibrosis.
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    Safety and Efficacy of AAV Retrograde Pancreatic Ductal Gene Delivery in Normal and Pancreatic Cancer Mice
    (Elsevier, 2017-09-30) Quirin, Kayla A.; Kwon, Jason J.; Alioufi, Arafat; Factora, Tricia; Temm, Constance J.; Jacobsen, Max; Sandusky, George E.; Shontz, Kim; Chicoine, Louis G.; Clark, K. Reed; Mendell, Joshua T.; Korc, Murray; Kota, Janaiah; Medical and Molecular Genetics, School of Medicine
    Recombinant adeno-associated virus (rAAV)-mediated gene delivery shows promise to transduce the pancreas, but safety/efficacy in a neoplastic context is not well established. To identify an ideal AAV serotype, route, and vector dose and assess safety, we have investigated the use of three AAV serotypes (6, 8, and 9) expressing GFP in a self-complementary (sc) AAV vector under an EF1α promoter (scAAV.GFP) following systemic or retrograde pancreatic intraductal delivery. Systemic delivery of scAAV9.GFP transduced the pancreas with high efficiency, but gene expression did not exceed >45% with the highest dose, 5 × 1012 viral genomes (vg). Intraductal delivery of 1 × 1011 vg scAAV6.GFP transduced acini, ductal cells, and islet cells with >50%, ∼48%, and >80% efficiency, respectively, and >80% pancreatic transduction was achieved with 5 × 1011 vg. In a KrasG12D-driven pancreatic cancer mouse model, intraductal delivery of scAAV6.GFP targeted acini, epithelial, and stromal cells and exhibited persistent gene expression 5 months post-delivery. In normal mice, intraductal delivery induced a transient increase in serum amylase/lipase that resolved within a day of infusion with no sustained pancreatic inflammation or fibrosis. Similarly, in PDAC mice, intraductal delivery did not increase pancreatic intraepithelial neoplasia progression/fibrosis. Our study demonstrates that scAAV6 targets the pancreas/neoplasm efficiently and safely via retrograde pancreatic intraductal delivery.