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Open Access Publications from the University of California

Scholarly Works (8 results)

  • Article
  • Peer Reviewed
UC Davis Previously Published Works (2018)
[This corrects the article DOI: 10.1371/journal.pone.0167573.].
    Cover page: Correction: Mice Hemizygous for a Pathogenic Mitofusin-2 Allele Exhibit Hind Limb/Foot Gait Deficits and Phenotypic Perturbations in Nerve and Muscle
    • Article
    • Peer Reviewed
    UC Davis Previously Published Works (2014)
    We provide evidence of cortical neuronopathy in myelin oligodendrocyte glycoprotein peptide-induced experimental autoimmune encephalomyelitis, an established model of chronic multiple sclerosis. To investigate phenotypic perturbations in neurons in this model, we used apoptotic markers and immunohistochemistry with antibodies to NeuN and other surrogate markers known to be expressed by adult pyramidal Layer V somas, including annexin V, encephalopsin, and Emx1. We found no consistent evidence of chronic loss of Layer V neurons but detected both reversible and chronic decreases in the expression of these markers in conjunction with evidence of cortical demyelination and presynaptic loss. These phenotypic perturbations were present in, but not restricted to, the neocortical Layer V. We also investigated inflammatory responses in the cortex and subcortical white matter of the corpus callosum and spinal dorsal funiculus and found that those in the cortex and corpus callosum were delayed compared with those in the spinal cord. Inflammatory infiltrates initially included T cells, neutrophils, and Iba1-positive microglia/macrophages in the corpus callosum, whereas only Iba1-positive cells were present in the cortex. These data indicate that we have identified a new temporal pattern of subtle phenotypic perturbations in neocortical neurons in this chronic multiple sclerosis model.
      Cover page: Neuronopathy in the Motor Neocortex in a Chronic Model of Multiple Sclerosis
      • Article
      • Peer Reviewed
      UC Davis Previously Published Works (2014)
      Current multiple sclerosis (MS) therapies only partially prevent chronically worsening neurological deficits, which are largely attributable to progressive loss of CNS axons. Prior studies of experimental autoimmune encephalomyelitis (EAE) induced in C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG peptide), a model of MS, documented continued axon loss for months after acute CNS inflammatory infiltrates had subsided, and massive astroglial induction of CCL2 (MCP-1), a chemokine for CCR2(+) monocytes. We now report that conditional deletion of astroglial CCL2 significantly decreases CNS accumulation of classically activated (M1) monocyte-derived macrophages and microglial expression of M1 markers during the initial CNS inflammatory phase of MOG peptide EAE, reduces the acute and long-term severity of clinical deficits and slows the progression of spinal cord axon loss. In addition, lack of astroglial-derived CCL2 results in increased accumulation of Th17 cells within the CNS in these mice, but also in greater confinement of CD4(+) lymphocytes to CNS perivascular spaces. These findings suggest that therapies designed to inhibit astroglial CCL2-driven trafficking of monocyte-derived macrophages to the CNS during acute MS exacerbations have the potential to significantly reduce CNS axon loss and slow progression of neurological deficits.
        Cover page: Conditional Ablation of Astroglial CCL2 Suppresses CNS Accumulation of M1 Macrophages and Preserves Axons in Mice with MOG Peptide EAE
        • Article
        • Peer Reviewed
        UC Davis Previously Published Works (2016)
        Charcot-Marie-Tooth disease type 2A (CMT2A), the most common axonal form of hereditary sensory motor neuropathy, is caused by mutations of mitofusin-2 (MFN2). Mitofusin-2 is a GTPase required for fusion of mitochondrial outer membranes, repair of damaged mitochondria, efficient mitochondrial energetics, regulation of mitochondrial-endoplasmic reticulum calcium coupling and axonal transport of mitochondria. We knocked T105M MFN2 preceded by a loxP-flanked STOP sequence into the mouse Rosa26 locus to permit cell type-specific expression of this pathogenic allele. Crossing these mice with nestin-Cre transgenic mice elicited T105M MFN2 expression in neuroectoderm, and resulted in diminished numbers of mitochondria in peripheral nerve axons, an alteration in skeletal muscle fiber type distribution, and a gait abnormality.
          Cover page: Mice Hemizygous for a Pathogenic Mitofusin-2 Allele Exhibit Hind Limb/Foot Gait Deficits and Phenotypic Perturbations in Nerve and Muscle
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (2017)
          Canavan disease is a leukodystrophy caused by aspartoacylase (ASPA) deficiency. The lack of functional ASPA, an enzyme enriched in oligodendroglia that cleaves N-acetyl-l-aspartate (NAA) to acetate and l-aspartic acid, elevates brain NAA and causes "spongiform" vacuolation of superficial brain white matter and neighboring gray matter. In children with Canavan disease, neuroimaging shows early-onset dysmyelination and progressive brain atrophy. Neuron loss has been documented at autopsy in some cases. Prior studies have shown that mice homozygous for the Aspa nonsense mutation Nur7 also develop brain vacuolation. We now report that numbers of cerebral cortical and cerebellar neurons are decreased and that cerebral cortex progressively thins in AspaNur7/Nur7 mice. This neuronal pathology is prevented by constitutive disruption of Nat8l, which encodes the neuronal NAA-synthetic enzyme N-acetyltransferase-8-like.

          Significance statement

          This is the first demonstration of cortical and cerebellar neuron depletion and progressive cerebral cortical thinning in an animal model of Canavan disease. Genetic suppression of N-acetyl-l-aspartate (NAA) synthesis, previously shown to block brain vacuolation in aspartoacylase-deficient mice, also prevents neuron loss and cerebral cortical atrophy in these mice. These results suggest that lowering the concentration of NAA in the brains of children with Canavan disease would prevent or slow progression of neurological deficits.
            Cover page: Suppressing N-Acetyl-l-Aspartate Synthesis Prevents Loss of Neurons in a Murine Model of Canavan Leukodystrophy
            • Article
            • Peer Reviewed
            UC Davis Previously Published Works (2007)

            Despite their large size, antibodies (Abs) are suitable carriers to deliver systemic radiotherapy, often molecular image-based, for lymphoma and leukemia. Lym-1 Ab has proven to be an effective radioisotope carrier, even in small amounts, for targeting human leukocyte antigen DR (HLA-DR), a surface membrane protein overexpressed on B-cell lymphoma. Pairs of molecules (referred to as ligands), shown by computational and experimental methods to bind to each of 2 sites within the Lym-1 epitopic region, have been linked to generate small (kDa) molecules (referred to as selective high-affinity ligands [SHALs]) to mimic the targeting properties of Lym-1 Ab. Methods: A lysine-polyethylene glycol (PEG) backbone was used to synthetically link 2 of the following ligands: deoxycholate, 5-leuenkephalin, triiodothyronine, thyronine, dabsyl-L-valine, and N-benzoyl-L-arginyl-4amino-benzoic acid to generate a series of 13 bidentate SHALs with a biotin or 1,4,7,10-tetraazacyclododecane-NN',N '',N'''-tetraacetic acid (DOTA) chelate attached to the linker. These SHALs have been assessed for their selectivity in binding to HLA-DR10-expressing cells and for their pharmacokinetics and tissue biodistribution in mice. Biotinylated versions of these SHALs discriminated cell lines positive for HLA-DR10 expression with near-nanomolar affinity. The DOTA versions of 4 SHALs were labeled with In-111 for pharmacokinetic studies in mice with HLA-DR10-expressing malignant Raji xenografts. Results: The bidentate, biotinylated, and DOTA-SHALs were synthesized in high-purity, multimilligram amounts. Mean radiochemical and product yields and purities were 90%, 75%, and 90% at mean specific activities of 3.9 MBq/mu g (105 mu Ci/mu g) for the In-111-labeled SHALs. As expected, rapid blood clearance and tumor targeting were observed. The pharmacokinetics of the SHALs was influenced by the component ligands. Biliary clearance, kidney localization, and serum receptor binding contributed to less favorable tumor targeting. Conclusion: A series of SHALs was readily synthesized in multimilligram amounts and showed the expected selective binding in vitro. Better selection of the SHAL components should provide second-generation SHALs with improved properties to fulfill the substantial potential of these novel molecular carriers for targeting.

              Cover page: Pharmacokinetic characterization in xenografted mice of a series of first-generation mimics for HLA-DR antibody, Lym-1, as carrier molecules to image and treat lymphoma
              • Article
              • Peer Reviewed
              UC Davis Previously Published Works (2014)
              Multiple sclerosis (MS) is characterized by central nervous system (CNS) inflammation, demyelination, and axonal degeneration. CXCL10 (IP-10), a chemokine for CXCR3+ T cells, is known to regulate T cell differentiation and migration in the periphery, but effects of CXCL10 produced endogenously in the CNS on immune cell trafficking are unknown. We created floxed cxcl10 mice and crossed them with mice carrying an astrocyte-specific Cre transgene (mGFAPcre) to ablate astroglial CXCL10 synthesis. These mice, and littermate controls, were immunized with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG peptide) to induce experimental autoimmune encephalomyelitis (EAE). In comparison to the control mice, spinal cord CXCL10 mRNA and protein were sharply diminished in the mGFAPcre/CXCL10fl/fl EAE mice, confirming that astroglia are chiefly responsible for EAE-induced CNS CXCL10 synthesis. Astroglial CXCL10 deletion did not significantly alter the overall composition of CD4+ lymphocytes and CD11b+ cells in the acutely inflamed CNS, but did diminish accumulation of CD4+ lymphocytes in the spinal cord perivascular spaces. Furthermore, IBA1+ microglia/macrophage accumulation within the lesions was not affected by CXCL10 deletion. Clinical deficits were milder and acute demyelination was substantially reduced in the astroglial CXCL10-deleted EAE mice, but long-term axon loss was equally severe in the two groups. We concluded that astroglial CXCL10 enhances spinal cord perivascular CD4+ lymphocyte accumulation and acute spinal cord demyelination in MOG peptide EAE, but does not play an important role in progressive axon loss in this MS model.
                Cover page: Deletion of astroglial CXCL10 delays clinical onset but does not affect progressive axon loss in a murine autoimmune multiple sclerosis model
                • Article
                • Peer Reviewed
                UC Davis Previously Published Works (2015)
                Canavan disease is caused by inactivating ASPA (aspartoacylase) mutations that prevent cleavage of N-acetyl-L-aspartate (NAA), resulting in marked elevations in central nervous system (CNS) NAA and progressively worsening leukodystrophy. We now report that ablating NAA synthesis by constitutive genetic disruption of Nat8l (N-acetyltransferase-8 like) permits normal CNS myelination and prevents leukodystrophy in a murine Canavan disease model.
                  Cover page: Ablating N-acetylaspartate prevents leukodystrophy in a Canavan disease model.
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