Our results demonstrate that APN overexpression reduces ischemic brain injury and improves neurobehavioral function recovery in aged mice than in young mice, suggesting APN is more beneficial in aged animals after ischemic stroke.

Background Gastric cancer (GC) remains one of the most common malignancieswith poor prognosis worldwide. Immunotherapy based on PD-1/PD-L1 immune checkpoints has achieved robust and durable responses in various types of cancer, but only a subset of gastric cancer patients benefits from it.Myeloid-derived suppressor cells (MDSCs) have been demonstrated to suppress antitumor immunityand induceresistanceto PD-1/PD-L1 blockade immunotherapy. Death receptor5 (DR5), a receptor of TNF-related apoptosis-inducing ligand(TRAIL), is upregulated in MDSCs and is also commonly expressed on cancer cells, making it a desirable target for both MDSCs and DR5-positive GC. In this study, we evaluated the MDSCs depleting and immune modulating effect of the agonist DR5 antibody (MD5-1), and tested the therapeutic effectof targeting DR5 in combination with anti-PD-L1 as a new strategyfor the treatment of GC. Methods The MDSCs and their DR5 expression insyngeneic GC murine model were evaluated. TheMDSCs depleting effect by MD5-1 wereinvestigated. We compared the antitumor efficacy of MD5-1 in GC bearing T cell-deficient nude mice andsyngeneic 615 mice, and assessed its immune correlates. The antitumor effect of MD5-1 combininganti-PD-L1 in syngeneic GC murine model were tested, the tumor growth, mice survival and intratumoral T cell infiltration and activation were evaluated. Results The MDSCs accumulate in the gastric tumor-bearing 615 mice express high levels of DR5. Targeting DR5 using MD5-1specifically depleted MDSCs and enhancedT cell antitumor response, resulted in tumor growth inhibition.MD5-1 enhanced the antitumor effect of anti-PD-L1 antibody, led to complete regression in 40% ofestablished tumors and significantly extended the survival tumor-bearing mice. The enhanced antitumor effect by MD5-1 combining anti-PD-L1 was associatedwith increased CD8+ T cell infiltration and activation. Conclusions These results show that targeting DR5 enhances the antitumor effect of PD-L1 blockadetherapy in gastric cancer through eliminating MDSCs and improving CD8+T cell antitumor response.Thus, targeting DR5 in combination with anti-PD-L1 may be a novel immunotherapy strategy forgastric cancer.

Introduction: Neurons of peri-infarct region in the cortex have effects on neurogenesis and remodeling after ischemic stroke. However the role of penumbral striatum neuron in neurogenesis and remodeling after ischemic stroke is unknown. In this study, we use optogenetic tools to specifically regulate the activity of striatum neuron and investigate its roles in neurogenesis and remodeling after ischemic stroke. Methods: Lentivirus carrying NpHR and YFP fusion protein under CaMKII promoter was injected into striatum of experimental mice. 7 days after injection, ferrule with fiber or optrode was implanted at the same position and MCAO surgery was performed 14 days after the injection. 4 days after MCAO, mice were stimulated with constant 594 nm laser for two 15-min sessions each day for 4 days. Electrophysiology test was used to confirm the validity of NpHR in vivo. Neurobehavioral tests were carried out at 3, 7 and 35 days after MCAO. Results: When stimulated with 594nm laser, the firing rate of striatum neuron was reduced in NpHR transduced mouse after MCAO. Immunohistochemistry showed that the number of BrdU and DCX double positive cells was significantly increased in the SVZ area. Nestin positive cells were increased both in SVZ and peri-infarct area. Western blotting showed that Netrin-1 expression was significantly up-regulated. BrdU and NeuN double positive cells was increased and brain atrophy volume was reduced in laser-stimulated mice compared with control mice (p<0.05). Neurobehavioral test showed that inhibition of striatum neuron promotes motor function after MCAO compared to the control (p<0.05). Conclusion: Laser induced activation of NpHR reduces the firing rate of penumbral striatum neuron using optogenetics tools. Inhibition of striatum neuron promotes proliferation and migration of neural progenietor cells and neurobehavioral function recovery. This effect is related to Netrin-1 secretion.