Human cortical organoids (hCOs), derived from human induced pluripotent stem cells (iPSCs), provide a platform to interrogate mechanisms of human brain development and di... More
Human cortical organoids (hCOs), derived from human induced pluripotent stem cells (iPSCs), provide a platform to interrogate mechanisms of human brain development and diseases in complex three- dimensional tissues. However, current hCO development methods lack important non-neural tissues, such as the surrounding meningeal layer, that have been shown to be essential for normal corticogenesis and brain development. Here, we first generated hCOs from a single rosette to create more homogenous organoids with consistent size around 250 µm by day 5. We then took advantage of a 3D co-culture system to encapsulate brain organoids with a thin layer of meningeal cells from the very early stages of cortical development. Immunostaining analysis was performed to display different cortical layer markers during different stages of development. Real-time monitoring of organoid development using IncuCyte displayed enhanced morphology and increased growth rate over time. We found that meningeal-encapsulated organoids illustrated better laminar organization by exhibiting higher expression of REELIN by Cajal–Retzius neurons. Presence of meningeal cells resulted in a greater expansion of TBR2 intermediate progenitor cells (IPCs), the deep cortical layer (CTIP2) and upper cortical layer (BRN2). Finally, meningeal-encapsulated organoids enhanced outer radial glial and astrocyte formation illustrated by stronger expression of HOPX and GFAP markers, respectively. This study presents a novel 3D co-culture platform to more closely mimic the in vivo cortical brain structure and enable us to better investigating mechanisms underlying the neurodevelopmental disorders during embryonic development. Less
Central nervous system (CNS) relapse is a significant cause of treatment failure among patients with acute lymphoblastic leukemia. In prior work we found that the meninge... More
Central nervous system (CNS) relapse is a significant cause of treatment failure among patients with acute lymphoblastic leukemia. In prior work we found that the meninges, the thin layer of tissue that covers the brain and spinal cord, harbor leukemia cells in the CNS. Importantly, direct interactions between leukemia and meningeal cells enabled leukemia chemoresistance. Herein, we show that an antibody targeting CD99, a transmembrane protein expressed on meningeal cells and many leukemia cells, disrupts adhesion between leukemia and meningeal cells and restores sensitivity of the leukemia cells to chemotherapy. This work identifies a mechanism regulating critical intercellular interactions within the CNS leukemia niche and may lead to novel therapeutic approaches for overcoming niche-mediated chemoresistance. Less
JC polyomavirus (JCPyV) establishes a lifelong persistence in roughly half the human population worldwide. The cells and tissues that harbor persistent virus in vivo are ... More
JC polyomavirus (JCPyV) establishes a lifelong persistence in roughly half the human population worldwide. The cells and tissues that harbor persistent virus in vivo are not known, but renal tubules and other urogenital epithelial cells are likely candidates as virus is shed in the urine of healthy individuals. In an immunosuppressed host, JCPyV can become reactivated and cause progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease of the central nervous system. Recent observations indicate that JCPyV may productively interact with cells in the choroid plexus and leptomeninges. To further study JCPyV infection in these cells, primary human choroid plexus epithelial cells and meningeal cells were challenged with virus, and their susceptibility to infection was compared to the human glial cell line, SVG-A. We found that JCPyV productively infects both choroid plexus epithelial cells and meningeal cells in vitro. Competition with the soluble receptor fragment LSTc reduced virus infection in these cells. Treatment of cells with neuraminidase also inhibited both viral infection and binding. Treatment with the serotonin receptor antagonist, ritanserin, reduced infection in SVG-A and meningeal cells. We also compared the ability of wild-type and sialic acid-binding mutant pseudoviruses to transduce these cells. Wild-type pseudovirus readily transduced all three cell types, but pseudoviruses harboring mutations in the sialic acid-binding pocket of the virus failed to transduce the cells. These data establish a novel role for choroid plexus and meninges in harboring virus that likely contributes not only to meningoencephalopathies but also to PML. JCPyV infects greater than half the human population worldwide and causes central nervous system disease in patients with weakened immune systems. Several recent reports have found JCPyV in the choroid plexus and leptomeninges of patients with encephalitis. Due to their role in forming the blood-cerebrospinal fluid barrier, the choroid plexus and leptomeninges are also poised to play roles in virus invasion of brain parenchyma, where infection of macroglial cells leads to the development of progressive multifocal leukoencephalopathy, a severely debilitating and often fatal infection. In this paper we show for the first time that primary choroid plexus epithelial cells and meningeal cells are infected by JCPyV, lending support to the association of JCPyV with meningoencephalopathies. These data also suggest that JCPyV could use these cells as reservoirs for the subsequent invasion of brain parenchyma. Less
Background. Hepatitis B virus (HBV) induces proliferation of human mesangial cells (HMCs), and extracellular matrix expression through the deposition of immune complexes ... More
Background. Hepatitis B virus (HBV) induces proliferation of human mesangial cells (HMCs), and extracellular matrix expression through the deposition of immune complexes in renal tissue. However, it is unclear whether HBV can directly affect HMCs. In this study, the effects of purified HBV on HMC proliferation and extracellular matrix expression in vitro was determined. Less
