Neuroprotective effect and mechanism of cPLA2 inhibitor increases autophagic flux on spinal cord injury / 中国骨伤

OBJECTIVE@#To investigate the mechanism of cytosolic phospholipase A2(cPLA2) inhibitor to improve neurological function after spinal cord injury (SCI).@*METHODS@#Thirty-six 3 months old female SD rats, with body mass (280±20) g, were divided into three groups (n=12):sham group, SCI group, and SCI+ arachidonyl trifluoromethyl ketone(AACOCF3) group. Balloon compression SCI model was established in all three groups. In the sham model group, the spinal cord compression model was created after the balloon was placed without pressure treatment, and the remaining two groups were pressurized with the balloon for 48 h. After successful modeling, rats in the SCI+AACOCF3 group were injected intraperitoneally with AACOCF3, a specific inhibitor of cPLA2. The remaining two groups of rats were injected intraperitoneally with saline. The animals were sacrificed in batches on 7 and 14 days after modeling, respectively. And the damaged spinal cord tissues were sampled for pathomorphological observation, to detect the expression of cPLA2 and various autophagic fluxPrelated molecules and test the recovery of motor function.@*RESULTS@#Spinal cord histomorphometry examination showed that the spinal cord tissue in the sham group was structurally intact, with normal numbers and morphology of neurons and glial cells. In the SCI group, spinal cord tissue fractures with large and prominent spinal cord cavities were seen. In the SCI+AACOCF3 group, the spinal cord tissue was more intact than in the SCI group, with more fused spinal cord cavities, more surviving neurons, and less glial cell hyperplasia. Western blot showed that the sham group had the lowest protein expression of LC3-Ⅱ, Beclin 1, p62, and cPLA2 compared with the SCI and SCI+AACOCF3 groups (P<0.05) and the highest protein expression of LC3-Ⅰ (P<0.05). P62 and cPLA2 expression in the SCI group were higher than in the SCI+AACOCF3 group (P<0.05). Behavioral observations showed that the time corresponding to BBB exercise scores was significantly lower in both the SCI and SCI+AACOCF3 groups than in the sham group (P<0.05). Scores at 3, 7, and 14 days after pressurization were higher in the SCI+AACOCF3 group than in the SCI group (P<0.05).@*CONCLUSION@#cPLA2 inhibitors can reduce neuronal damage secondary to SCI, promote neurological recovery and improve motor function by improving lysosomal membrane permeability and regulating autophagic flux.

Gold nanoparticle-directed autophagy intervention for antitumor immunotherapy via inhibiting tumor-associated macrophage M2 polarization

Tumor-associated macrophages (TAMs), one of the dominating constituents of tumor microenvironment, are important contributors to cancer progression and treatment resistance. Therefore, regulation of TAMs polarization from M2 phenotype towards M1 phenotype has emerged as a new strategy for tumor immunotherapy. Herein, we successfully initiated antitumor immunotherapy by inhibiting TAMs M2 polarization via autophagy intervention with polyethylene glycol-conjugated gold nanoparticles (PEG-AuNPs). PEG-AuNPs suppressed TAMs M2 polarization in both in vitro and in vivo models, elicited antitumor immunotherapy and inhibited subcutaneous tumor growth in mice. As demonstrated by the mRFP-GFP-LC3 assay and analyzing the autophagy-related proteins (LC3, beclin1 and P62), PEG-AuNPs induced autophagic flux inhibition in TAMs, which is attributed to the PEG-AuNPs induced lysosome alkalization and membrane permeabilization. Besides, TAMs were prone to polarize towards M2 phenotype following autophagy activation, whereas inhibition of autophagic flux could reduce the M2 polarization of TAMs. Our results revealed a mechanism underlying PEG-AuNPs induced antitumor immunotherapy, where PEG-AuNPs reduce TAMs M2 polarization via induction of lysosome dysfunction and autophagic flux inhibition. This study elucidated the biological effects of nanomaterials on TAMs polarization and provided insight into harnessing the intrinsic immunomodulation capacity of nanomaterials for effective cancer treatment.

Ginsenoside Rb1 improving autophagic flux against myocardial ischemia reperfusion injury in isolated-heart of rat / 解剖学报

Objective To explore the protective effect of ginsenoside Rb1 on the myocardial ischemia / reperfusion (I / R) injury in rats in vitro. Methods Totally 60 adult male SD rats were randomly divided into 6 groups:sham group,I / R group,ginsenosde Rb1 pretreatment groups(at the doses of 1 μmol / L,5 μmol / L,10 μmol / L and 20 μmol / L,respectively), 10 in each group. The Langendorff perfusion system was used to establish I / R model. The Lab Chart electrophysiological system was used to monitor real-time heart function by monitoring heart rate (HR), left ventricular development pressure (LVDP) and left ventricular development pressure (± dp / dtmax). TTC staining method was used to measure myocardial infarct size. The Western blotting were used to assay Beclin 1, LC3, p62 and Lamp 2 expression, respectively. The immunohistochemistry were used to assay Beclin 1 expression. Results Ginsenoside Rbl of all the four different concent rations improved the decrease of LVDP and ± dp / dtmax arising from myocardial I / R injury. Meanwhile, ginsenoside Rbl significantly decreased the area of cardial infarction. Ginsenoside Rb1 (10 μmol / L) precondition group protected the heart most significantly (P<0. 05). The expression of Beclin 1 with I / R increased significantly in the cytoplasm of cardiomyocytes. Moreover, Beclin 1 expression decreased after addition pretreatment with ginsenoside Rb1 (10 μmol / L) (P < 0. 05). Compared with sham group, we found that the autophagic flux was impaired in I / R group which the expression of Beclin 1, LC3 and p62 increased significantly, as well as the expression of Lamp 2 decreased significantly. On the other hand, pretreatment with ginsenoside Rb1 (10 μmol / L) could reverse impaired autophagic flux (P < 0. 05). Conclusion Ginsenoside Rbl demonstrates pharmacological preconditioning effect and protects against myocardial I / R injury by improving damaged-autophagy flux, the dose of 10 μmol / L precondition protectes the heart most significantly.