Human umbilical cord derived mesenchymal stem cells overexpressing HO-1 attenuate neural injury and enhance functional recovery by inhibiting inflammation in stroke mice.

AIMS: The current evidence demonstrates that mesenchymal stem cells (MSCs) hold therapeutic potential for ischemic stroke. However, it remains unclear how changes in the secretion of MSC cytokines following the overexpression of heme oxygenase-1 (HO-1) impact excessive inflammatory activation in a mouse ischemic stroke model. This study investigated this aspect and provided further insights. METHODS: The middle cerebral artery occlusion (MCAO) mouse model was established, and subsequent injections of MSC, MSCHO-1 , or PBS solutions of equal volume were administered via the mice's tail vein. Histopathological analysis was conducted on Days 3 and 28 post-MCAO to observe morphological changes in brain slices. mRNA expression levels of various factors, including IL-1ß, IL-6, IL-17, TNF-α, IL-1Ra, IL-4, IL-10, TGF-ß, were quantified. The effects of MSCHO-1 treatment on neurons, microglia, and astrocytes were observed using immunofluorescence after transplantation. The polarization direction of macrophages/microglia was also detected using flow cytometry. RESULTS: The results showed that the expression of anti-inflammatory factors in the MSCHO-1 group increased while that of pro-inflammatory factors decreased. Small animal fluorescence studies and immunofluorescence assays showed that the homing function of MSCsHO-1 was unaffected, leading to a substantial accumulation of MSCsHO-1 in the cerebral ischemic region within 24 h. Neurons were less damaged, activation and proliferation of microglia were reduced, and polarization of microglia to the M2 type increased after MSCHO-1 transplantation. Furthermore, after transplantation of MSCsHO-1 , the mortality of mice decreased, and motor function improved significantly. CONCLUSION: The findings indicate that MSCs overexpressing HO-1 exhibited significant therapeutic effects against hyper-inflammatory injury after stroke in mice, ultimately promoting recovery after ischemic stroke.

Exogenous NADPH exerts a positive inotropic effect and enhances energy metabolism via SIRT3 in pathological cardiac hypertrophy and heart failure.

BACKGROUND: Therapies are urgently required to ameliorate pathological cardiac hypertrophy and enhance cardiac function in heart failure. Our preliminary experiments have demonstrated that exogenous NADPH exhibits a positive inotropic effect on isolated heart. This study aims to investigate the positive inotropic effects of NADPH in pathological cardiac hypertrophy and heart failure, as well as the underlying mechanisms involved. METHODS: Endogenous plasma NADPH contents were determined in patients with chronic heart failure and control adults. The positive inotropic effects of NADPH were investigated in isolated toad heart or rat heart. The effects of NADPH were investigated in isoproterenol (ISO)-induced cardiac hypertrophy or transverse aortic constriction (TAC)-induced heart failure. The underlying mechanisms of NADPH were studied using SIRT3 knockout mice, echocardiography, Western blotting, transmission electron microscopy, and immunoprecipitation. FINDINGS: The endogenous NADPH content in the blood of patients and animals with pathological cardiac hypertrophy or heart failure was significantly reduced compared with age-sex matched control subjects. Exogenous NADPH showed positive inotropic effects on the isolated normal and failing hearts, while antagonism of ATP receptor partially abolished the positive inotropic effect of NADPH. Exogenous NADPH administration significantly reduced heart weight indices, and improved cardiac function in the mice with pathological cardiac hypertrophy or heart failure. NADPH increased SIRT3 expression and activity, deacetylated target proteins, improved mitochondrial function and facilitated ATP production in the hypertrophic myocardium. Importantly, inhibition of SIRT3 abolished the positive inotropic effect of NADPH, and the anti-heart failure effect of NADPH was significantly reduced in the SIRT3 Knockout mice. INTERPRETATION: Exogenous NADPH shows positive inotropic effect and improves energy metabolism via SIRT3 in pathological cardiac hypertrophy and heart failure. NADPH thus may be one of the potential candidates for the treatment of pathological cardiac hypertrophy or heart failure. FUNDING: This work was supported by grants from the National Natural Science Foundation of China (No. 81973315, 82173811, 81730092), Natural Science Foundation of Jiangsu Higher Education (20KJA310008), Jiangsu Key Laboratory of Neuropsychiatric Diseases (BM2013003) and the Priority Academic Program Development of the Jiangsu Higher Education Institutes (PAPD).

In Situ Attached Photothermal Immunomodulation-Enhanced Nanozyme for the Inhibition of Postoperative Malignant Glioma Recurrence.

Glioblastoma (GBM) is one of the most challenging malignant brain tumors to treat. Herein, we describe a nanoenzyme hemostatic matrix strategy with the tumor cavity in situ application that simultaneously serves as photothermal agent and induces immunogenic cell death after GBM surgical resection to enhance the antitumor immunity and delay tumor recurrence. The hemostatic matrix system (Surgiflo@PCN) contains Surgiflo, a multispace structure that can be used to penetrate different shapes of tumor cavities to prevent postoperative tumor cavity hemorrhage. As well, porous palladium-copper nanoclusters (PCNs) have adjustable enzyme-like activities (oxidase, peroxidase, and catalase) responsible for formation of reactive oxygen species (ROS) under near-infrared (808 nm) laser irradiation. When the Surgiflo@PCN entered the resected tumor cavity, the first action was the direct killing of glioma cells via ROS and photothermal therapy (PTT). The second action was the induction of immunogenic cell death by PCN-enhanced oxidative stress and PTT, which reversed the immunosuppressive tumor microenvironment and enhanced the antitumor immune response. This eradicated residual glioma cells and prevented recurrence. The collective findings demonstrate that Surgiflo@PCN kills glioma cells directly through ROS and PTT and enhances antiglioma immunity and kills glioma cells indirectly. The "one-stone, two-birds" strategy could become an effective photothermal immunotherapy in GBM patients.

Antioxidant Cascade Nanoenzyme Antagonize Inflammatory Pain by Modulating MAPK/p-65 Signaling Pathway.

Chronic pain has attracted wide interest because it is a major obstacle affecting the quality of life. Consequently, safe, efficient, and low-addictive drugs are highly desirable. Nanoparticles (NPs) with robust anti-oxidative stress and anti-inflammatory properties possess therapeutic possibilities for inflammatory pain. Herein, a bioactive zeolitic imidazolate framework (ZIF)-8-capped superoxide dismutase (SOD) and Fe3 O4 NPs (SOD&Fe3 O4 @ZIF-8, SFZ) is developed to achieve enhanced catalytic, antioxidative activities, and inflammatory environment selectivity, ultimately improving analgesic efficacy. SFZ NPs reduce tert-butyl hydroperoxide (t-BOOH)-induced reactive oxygen species (ROS) overproduction, thereby depressing the oxidative stress and inhibiting the lipopolysaccharide (LPS)-induced inflammatory response in microglia. After intrathecal injection, SFZ NPs efficiently accumulate at the lumbar enlargement of the spinal cord and significantly relieve complete Freund's adjuvant (CFA)-induced inflammatory pain in mice. Moreover, the detailed mechanism of inflammatory pain therapy via SFZ NPs is further studied, where SFZ NPs inhibit the activation of the mitogen-activated protein kinase (MAPK)/p-65 signaling pathway, leading to reductions in phosphorylated protein levels (p-65, p-ERK, p-JNK, and p-p38) and inflammatory factors (tumor necrosis factor [TNF]-α, interleukin [IL]-6, and IL-1ß), thereby preventing microglia and astrocyte activation for acesodyne. This study provides a new cascade nanoenzyme for antioxidant treatments and explores its potential applications as non-opioid analgesics.

Involvement of Histone Lysine Crotonylation in the Regulation of Nerve-Injury-Induced Neuropathic Pain.

Histone lysine crotonylation (KCR), a novel epigenetic modification, is important in regulating a broad spectrum of biological processes and various diseases. However, whether KCR is involved in neuropathic pain remains to be elucidated. We found KCR occurs in macrophages, sensory neurons, and satellite glial cells of trigeminal ganglia (TG), neurons, astrocytes, and microglia of the medulla oblongata. KCR in TG was detected mainly in small and medium sensory neurons, to a lesser extent in large neurons. Peripheral nerve injury elevated KCR levels in macrophages in the trigeminal and dorsal root ganglia and microglia in the medulla oblongata but reduced KCR levels in sensory neurons. Inhibition of histone crotonyltransferases (p300) by intra-TG or intrathecal administration of C646 significantly alleviated partial infraorbital nerve transection (pIONT)- or spinal nerve ligation (SNL)-induced mechanical allodynia and thermal hyperalgesia. Intra-TG or intrathecal administration of Crotonyl coenzyme A trilithium salt to upregulate KCR dose-dependently induced mechanical allodynia and thermal hyperalgesia in mice. Mechanismly, inhibition of p300 alleviated pIONT-induced macrophage activation and reduced the expression of pain-related inflammatory cytokines Tnfα, Il1ß and chemokines Ccl2 and Cxcl10. Correspondingly, exogenous crotonyl-CoA induced macrophage activation and the expression of Tnfα, Il1ß, Il6, Ccl2 and Ccl7 in TG, which C646 can repress. These findings suggest that histone crotonylation might be functionally involved in neuropathic pain and neuroinflammation regulation.

Intravenous Administration of Triptonide Attenuates CFA-Induced Pain Hypersensitivity by Inhibiting DRG AKT Signaling Pathway in Mice.

BACKGROUND: Currently, medical treatment of inflammatory pain is limited by a lack of safe and effective therapies. Triptonide (TPN), a major component of Tripterygium wilfordii Hook.f. with low toxicity, has been shown to have good anti-inflammatory and neuroprotective effects. The present study aims to investigate the effects of TPN on chronic inflammatory pain. MATERIALS AND METHODS: Inflammatory pain was induced by intraplantar injection of complete Freund's adjuvant (CFA). TPN's three different doses were intravenously administered to compare the analgesic efficacy: 0.1 mg/kg, 0.5 mg/kg, and 2.0 mg/kg. The foot swelling was quantitated by measuring paw volume. Mechanical allodynia and thermal hyperalgesia were assessed with von Frey filament testing and Hargreaves' test, respectively. Western blots, qRT-PCR and immunofluorescence tests were used to analyze the expression of pAKT, tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1ß), and interleukin 6 (IL-6). Two AKT inhibitors, AKT inhibitor Ⅳ and MK-2206, were used to examine AKT's effects on pain behavior and cytokines expression. RESULTS: Intravenous treatment with TPN attenuated CFA-induced paw edema, mechanical allodynia, and thermal hyperalgesia. Western blotting and immunofluorescence results showed that CFA induced AKT activation in the dorsal root ganglion (DRG) neurons. However, these effects were suppressed by treatment with TPN. Furthermore, TPN treatment inhibited CFA-induced increase of pro-inflammatory cytokines, including TNF-α, IL-1ß, and IL-6. Consistent with the in vivo data, TPN inhibited LPS-induced Akt phosphorylation and inflammatory mediator production in ND7/23 cells. Finally, intrathecal treatment with AKT inhibitor Ⅳ or MK-2206, attenuated CFA-induced mechanical allodynia and thermal hyperalgesia, and simultaneously decreased the mRNA expression of TNF-α, IL-1ß, and IL-6 in DRG. CONCLUSION: These data indicate that TPN attenuates CFA-induced pain potentially via inhibiting AKT-mediated pro-inflammatory cytokines production in DRG. TPN may be used for the treatment of chronic inflammatory pain.

The inhibition of Kir2.1 potassium channels depolarizes spinal microglial cells, reduces their proliferation, and attenuates neuropathic pain.

Spinal microglia change their phenotype and proliferate after nerve injury, contributing to neuropathic pain. For the first time, we have characterized the electrophysiological properties of microglia and the potential role of microglial potassium channels in the spared nerve injury (SNI) model of neuropathic pain. We observed a strong increase of inward currents restricted at 2 days after injury associated with hyperpolarization of the resting membrane potential (RMP) in microglial cells compared to later time-points and naive animals. We identified pharmacologically and genetically the current as being mediated by Kir2.1 ion channels whose expression at the cell membrane is increased 2 days after SNI. The inhibition of Kir2.1 with ML133 and siRNA reversed the RMP hyperpolarization and strongly reduced the currents of microglial cells 2 days after SNI. These electrophysiological changes occurred coincidentally to the peak of microglial proliferation following nerve injury. In vitro, ML133 drastically reduced the proliferation of BV2 microglial cell line after both 2 and 4 days in culture. In vivo, the intrathecal injection of ML133 significantly attenuated the proliferation of microglia and neuropathic pain behaviors after nerve injury. In summary, our data implicate Kir2.1-mediated microglial proliferation as an important therapeutic target in neuropathic pain.

Paclitaxel-activated astrocytes produce mechanical allodynia in mice by releasing tumor necrosis factor-α and stromal-derived cell factor 1.

BACKGROUND: Paclitaxel is a widely used and potent chemotherapeutic agent for the treatment of cancer. However, patients receiving paclitaxel often develop an acute pain syndrome for which there are few treatment options. Astrocytes play an important role in the pathogenesis of pain in multiple preclinical models, as well as in paclitaxel-treated rodents. However, it is still unclear what the exact contribution of astrocytes may be in paclitaxel-associated acute pain syndrome (P-APS). METHODS: P-APS was modeled by a single systemic or intrathecal injection of paclitaxel and astrocyte contribution tested by immunohistochemical, pharmacological, and behavioral approaches. Cell cultures were also prepared to assess whether paclitaxel treatment directly activates astrocytes and whether intrathecal injection of paclitaxel-treated astrocytes produces pain that is reminiscent of P-APS. RESULTS: Systemic injection of paclitaxel resulted in increased expression of glial fibrillary acidic protein (a common marker of astrocytic activation), as well as both systemic or intrathecal injection of paclitaxel induced pain hypersensitivity indicated by the development of mechanical allodynia, which was significantly reversed by the astrocytic inhibitor L-α-AA. Cultured astrocytes were activated by paclitaxel with significant increases in protein levels for tumor necrosis factor-α (TNF-α) and stromal-derived cell factor 1 (SDF-1). Importantly, intrathecal injection of paclitaxel-activated astrocytes produced mechanical allodynia that was reversed by TNF-α and SDF-1 neutralizing antibodies. CONCLUSION: Our results suggest for the first time that paclitaxel can directly activate astrocytes, which are sufficient to produce acute pain by releasing TNF-α and SDF-1. Targeting astrocytes and these cytokines may offer new treatments for P-APS.