Chimeric Antigen Receptor T Cells With Modified Interleukin-13 Preferentially Recognize IL13Rα2 and Suppress Malignant Glioma: A Preclinical Study.

Background: Interleukin-13 receptor α 2 (IL13Rα2) is a promising tumor-directed antigen of malignant glioma (MG). Here, we examine the efficacy and safety of T cells containing a YYB-103 chimeric antigen receptor (CAR) that can preferentially bind to IL13Rα2 on MG cells. Methods: IL13 was modified on the extracellular domain by substitution of amino acids with E13K, R66D, S69D, and R109K and stably transfected into human T cells using a retroviral vector. The in vitro efficacy of YYB-103 CAR T cells was tested in cell lines with differing IL13Rα1 and IL13Rα2 expression. The in vivo efficacy of intracerebroventricular (i.c.v.) and intravenous (i.v.) routes of YYB-103 CAR T-cell administration were tested in orthotopic MG mouse models. Immunohistochemical staining of MG was performed using WHO grade 3/4 surgical specimens from 53 patients. IL13Rα2 expression was quantified by H-score calculated from staining intensity and percentage of positive cells. Results: Binding affinity assay of YYB-103 verified apparently nil binding to IL13Rα1, which was more selective than previously reported IL13 modification (E13Y). YYB-103 CAR T cells showed selective toxicity toward co-cultured U87MG (IL13Rα1+/IL13Rα2+) cells but not A431 (IL13Rα1+/IL13Rα2-) cells. Consistently, YYB-103 CAR T cells suppressed tumor growth in nude mice receiving orthotopic injection of U87 MG cells. Both i.c.v. and i.v. injections of YYB-103 CAR T cells reduced tumor volume and prolonged overall survival of tumor-bearing mice. The median H-score for IL13Rα2 in patient-derived MG tissue was 5 (mean, 57.5; SD, 87.2; range, 0 to 300). Conclusion: This preclinical study demonstrates the efficacy of IL13Rα2-targeted YYB-103 CAR T cells against MG cells. The use of modified IL13 to construct a CAR facilitated the selective targeting of IL13Rα2-expressing MG cells while sparing IL13Rα1-expressing cells. Notably, YYB-103 CAR T cells exhibited effective blood-brain barrier crossing, suggesting compatibility with i.v. administration rather than intracranial injection. Additionally, the high H-score for IL13Rα2 in glioblastoma, especially in conjunction with the poor prognostic markers of wild-type isocitrate dehydrogenase-1 (IDH-1) and unmethylated O6-methyl guanine methyl-transferase (MGMT), could be used to determine the eligibility of patients with recurrent glioblastoma for a future clinical trial of YYB-103 CAR T cells.

ALS-Related Mutant SOD1 Aggregates Interfere with Mitophagy by Sequestering the Autophagy Receptor Optineurin.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive demise of motor neurons. One of the causes of familial ALS is the mutation of the gene encoding superoxide dismutase 1 (SOD1), which leads to abnormal protein aggregates. How SOD1 aggregation drives ALS is still poorly understood. Recently, ALS pathogenesis has been functionally implicated in mitophagy, specifically the clearance of damaged mitochondria. Here, to understand this mechanism, we investigated the relationship between the mitophagy receptor optineurin and SOD1 aggregates. We found that mutant SOD1 (mSOD1) proteins associate with and then sequester optineurin, which is required to form the mitophagosomes, to aggregates in N2a cells. Optineurin recruitment into mSOD1 aggregates resulted in a reduced mitophagy flux. Furthermore, we observed that an exogenous augmentation of optineurin alleviated the cellular cytotoxicity induced by mSOD1. Taken together, these studies demonstrate that ALS-linked mutations in SOD1 interfere with the mitophagy process through optineurin sequestration, suggesting that the accumulation of damaged mitochondria may play a crucial role in the pathophysiological mechanisms contributing to ALS.

Amyotrophic lateral sclerosis-related mutant superoxide dismutase 1 aggregates inhibit 14-3-3-mediated cell survival by sequestration into the JUNQ compartment.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by motor neuron loss in the spinal cord and brain. Mutations in the superoxide dismutase 1 (SOD1) gene have been linked to familial ALS. To elucidate the role of SOD1 mutations in ALS, we investigated 14-3-3, a crucial regulator of cell death that was identified in patients with familial ALS. In a transgenic mouse model (SOD1-G93A) of ALS, 14-3-3 co-localized with mutant SOD1 aggregates and was more insoluble in the spinal cords of mutant SOD1 transgenic mice than in those of wild-type mice. Immunofluorescence and co-immunoprecipitation experiments showed that the 14-3-3ɛ and θ isoforms interact with mutant SOD1 aggregates in the juxtanuclear quality control compartment of N2a neuroblastoma cells. Fluorescence loss in photobleaching experiments revealed that movement of the isoforms of 14-3-3 was markedly reduced in SOD1 aggregates. Bax translocation into and cytochrome c release from the mitochondria were promoted by the sequestration of 14-3-3 into mutant SOD1 aggregates, increasing cell death. Mutant SOD1 aggregates were dissolved by the Hsp104 chaperone, which increased the interaction of 14-3-3 with Bax, reducing cell death. Our study demonstrates that mutant SOD1 inhibits 14-3-3-mediated cell survival. This information may contribute to the identification of a novel therapeutic target for ALS.

Motor neurons derived from ALS-related mouse iPS cells recapitulate pathological features of ALS.

Amyotrophic lateral sclerosis (ALS) is a late-onset progressive neurodegenerative disease characterized by the loss of motor neurons in the spinal cord and brain. Mutations in Cu/Zn superoxide dismutase 1 (SOD1) are known to induce ALS. Although many research models have been developed, the exact pathological mechanism of ALS remains unknown. The recently developed induced pluripotent stem (iPS) cell technology is expected to illuminate the pathological mechanisms and new means of treatment for neurodegenerative diseases. To determine the pathological mechanism of ALS, we generated mouse iPS (miPS) cells from experimental ALS transgenic mice and control mice and characterized the cells using molecular biological methods. The generated miPS cells expressed many pluripotent genes and differentiated into three germ layers in vitro and in vivo. Motor neurons derived from ALS-related miPS cells recapitulated the pathological features of ALS. The ALS-model motor neurons showed SOD1 aggregates, as well as decreased cell survival rate and neurite length compared with wild-type motor neurons. Our study will be helpful in revealing the mechanism of motor neuronal cell death in ALS.

Neural stem cells inhibit melanin production by activation of Wnt inhibitors.

BACKGROUND: Melanin for skin pigmentation is synthesized from tyrosine via an enzymatic cascade that is controlled by tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase/tyrosinase related protein 2 (Dct/TRP2), which are the targets of microphthalmia-associated transcription factor (MITF). MITF is a master regulator of pigmentation and a target of ß-catenin in Wnt/ß-catenin signaling during melanocyte differentiation. Stem cells have been used in skin pigmentation studies, but the mechanisms were not determined for the conditioned medium (CM)-mediated effects. OBJECTIVES: In this study, the inhibition and mechanisms of melanin synthesis were elucidated in B16 melanoma cells and UV-B irradiated C57/BL-6 mice that were treated with human neural stem cell-conditioned medium (NSC-CM). METHODS: B16-F10 melanoma cells (1.5×10(4)cells/well) and the shaved dorsal skin of mice were pretreated with various amount (5, 10, 20, 50, and 100%) of NSC-CM. Melanin contents and TYR activity were measured by a Spectramax spectrophotometer. The expression of TYR, TRP1, Dct/TRP2, MITF, ß-catenin and Wnt inhibitors were evaluated by RT-PCR and western blot. The dorsal skin samples were analyzed by immunofluorescence with various antibodies and compared with that control of tissues. RESULTS: Marked decreases were evident in melanin content and TYR, TRP1, DCT/TRP2, MITF, and ß-catenin expression in B16 cells and C57/BL-6 mice. NSC-CM negatively regulated Wnt/ß-catenin signaling by decreasing the expression of ß-catenin protein, which resulted from robust expression of Wnt inhibitors Dickkopf-1 (DKK1) and secreted frizzled-related protein 2 (sFRP2). CONCLUSIONS: These results demonstrate that NSC-CM suppresses melanin production in vitro and in vivo, suggesting that factors in NSC-CM may play an important role in deregulation of epidermal melanogenesis.

Characterization and Hsp104-induced artificial clearance of familial ALS-related SOD1 aggregates.

Hsp104, a molecular chaperone protein, originates from Saccharomyces cerevisiae and shows potential for development as a therapeutic disaggregase for the treatment of neurodegenerative disorders. This study shows that aggregates of mutant superoxide dismutase 1 (SOD1), which cause amyotrophic lateral sclerosis (ALS), are disaggregated by Hsp104 in an ATP-dependent manner. Mutant SOD1 aggregates were first characterized using fluorescence loss in photobleaching experiments based on the reduced mobility of aggregated proteins. Hsp104 restored the mobility of mutant SOD1 proteins to a level comparable with that of the wild-type. However, ATPase-deficient Hsp104 mutants did not restore mobility, suggesting that, rather than preventing aggregation, Hsp104 disaggregates mutant SOD1 after it has aggregated. Despite the restored mobility, however, mutant SOD1 proteins existed as trimers or other higher-order structures, rather than as naturally occurring dimers. This study sheds further light on the mechanisms underlying the disaggregation of SOD1 mutant aggregates in ALS.