Yanyan Li

Abstract Restoring joint homeostasis is crucial for relieving osteoarthritis (OA). Current strategies are limited to unilateral efforts in joint lubrication, inhibition of inflammation, free radicals scavenging, and cartilage regeneration. Herein, by modifying molybdenum disulfide (MoS 2 ) with Mg 2+ ‐doped polydopamine and coating with polysulfobetaines, a dual‐bionic photothermal nanozyme (MPMP) is constructed to mimic antioxidases/hyaluronan synthase for OA therapy. Photothermally enhanced lubrication lowers the coefficient of friction (0.028) in the early stage of OA treatment. The antioxidases‐mimicking properties of MPMP nanozyme contribute to eliminating reactive oxygen and nitrogen species (ROS/RNS) (over 90% of scavenging ratio for H 2 O 2 /·OH/O · 2 – /DPPH/ABTS + ) and supplying O 2 . With NIR irradiation, the MPMP nanozyme triggers thermogenesis (upregulating HSP70 expression) and Mg 2+ release, which promotes the chondrogenesis in inflammatory conditions by deactivating NF‐κB/IL‐17 signaling pathways and enhancing MAPK signaling pathway. Benefiting from HSP70 and Mg 2+ , MPMP‐NIR shows HAS‐mimicking activity to increase the intracellular (twofold) and extracellular (3.12‐fold) HA production. Therefore, MPMP‐NIR demonstrates superior spatiotemporally therapeutic effect on OA in mice model, in terms of osteophytes (83.41% of reduction), OARSI scores (88.57% of reduction), and ACAN expression (2.70‐fold of increment). Hence, insights into dual‐bionic nanozymes can be a promising strategy for OA therapy or other inflammation‐related diseases.

BACKGROUND: Chimeric antigen receptor (CAR)-T immunotherapy fails to treat solid tumors due in part to immunosuppressive microenvironment. Excess lactate produced by tumor glycolysis increases CAR-T immunosuppression. The mechanism of lactate inducing the formation of immunosuppressive microenvironment remains to be further explored. METHODS: Immunocyte subpopulations and molecular characteristics were analyzed in the orthotopic xenografts of nude mice using flow cytometry assay and immunohistochemical staining after oxamate, a lactate dehydrogenase A (LDHA) inhibitor, and control T or CAR-T cells injection alone or in combination. RT-qPCR, western blot, flow cytometry, immunofluorescence, luciferase reporter assay, chromatin immunoprecipitation and ELISA were performed to measure the effect of lactate on the regulation of CD39, CD73 and CCR8 in cultured glioma stem cells, CD4 + T cells or macrophages. RESULTS: Oxamate promoted immune activation of tumor-infiltrating CAR-T cells through altering the phenotypes of immune molecules and increasing regulatory T (Treg) cells infiltration in a glioblastoma mouse model. Lactate accumulation within cells upregulated CD39, CD73 and CCR8 expressions in both lactate-treated cells and glioma stem cells-co-cultured CD4 + T cells and macrophages, and intracellular lactate directly elevated the activities of these gene promotors through histone H3K18 lactylation. CONCLUSIONS: Utilizing lactate generation inhibitor not only reprogramed glucose metabolism of cancer stem cells, but also alleviated immunosuppression of tumor microenvironment and reduced tumor-infiltrating CAR-Treg cells, which may be a potential strategy to enhance CAR-T function in glioblastoma therapy.

Vascular endothelial growth factor (VEGF) plays a neuroprotective role in mice harboring mutations of copper-zinc superoxide dismutase 1 (SOD1) in familial amyotrophic lateral sclerosis (ALS). Conversely, the loss of VEGF expression through genetic depletion can give rise to a phenotype resembling ALS independent of SOD1 mutations. Here, we observe a profound downregulation of VEGF mRNA expression in spinal cords of G93A SOD1 mice that occurred early in the course of the disease. Using an in vitro culture model of glial cells expressing mutant SOD1, we demonstrate destabilization and downregulation of VEGF RNA with concomitant loss of protein expression that correlates with level of transgene expression. Using a luciferase reporter assay, we show that this molecular effect is mediated through a portion of the VEGF 3'-untranslated region (UTR) that harbors a class II adenylate/uridylate-rich element. Other mutant forms of SOD1 produced a similar negative effect on luciferase RNA and protein expression. Mobility shift assay with a VEGF 3'-UTR probe reveals an aberrantly migrating complex that contains mutant SOD1. We further show that the RNA stabilizing protein, HuR (human antigen R), is translocated from nucleus to cytoplasm in mutant SOD1 cells in vitro and mouse motor neurons in vivo. In summary, our data suggest that mutant SOD1 gains a novel function, possibly by altering the ribonucleoprotein complex with the VEGF 3'-UTR. We postulate that the resultant dysregulation of VEGF posttranscriptional processing critically reduces the level of this neuroprotective growth factor and accelerates the neurodegenerative process in ALS.