Transplantation of Lymphocytes Co-Cultured with Human Cord Blood-Derived Multipotent Stem Cells Attenuates Inflammasome Activity in Ischemic Stroke

Background: Manipulating the immune inflammatory response after cerebral ischemia has been a novel therapeutic strategy for ischemic stroke. This study attempted to investigate the effects of the transplantation of lymphocytes co-cultured with human cord blood-derived multipotent stem cells (HCB-SCs) on the inflammatory response in transient middle cerebral occlusion (tMCAO) rats. Methods: The tMCAO rats were subjected to the transplantation of lymphocytes co-cultured with HCB-SCs through tail vein injection. Infarct size and neurological de fi cits were measured at 48 hrs after stroke. Neurological de fi cits were assessed using Bederson's scoring system and tape removal test. Blood T cell flow cytometry was performed to measure the differentiation of regulatory T cells (Tregs). Western blot was used to detect the protein levels of inflammation-related molecules, apoptosis-related molecule, and signaling molecules in ischemic brain. TUNEL staining was performed to analyze cell apoptosis in ischemic cerebral cortex. Results: The transplantation of lymphocytes co-cultured with HCB-SCs significantly improved the neurological defects, reduced ischemic brain damage, and increased the proportion of peripheral CD4(+)CD25(+)Foxp3(+) Tregs. Meanwhile, the transplantation of co-cultured cells decreased the expression of NLRP3 inflammasome and associated factors, such as caspase-1 and IL-1beta, and inhibited the activation of NF-kappaB, ERK and caspase-3 in ischemic brain. The co-cultured cells significantly decreased the number of tMCAO-induced cell apoptosis. Conclusion: Lymphocytes co-cultured with HCB-SCs exhibit a neuroprotective effect after ischemic stroke by promoting Tregs differentiation and suppressing NLRP3 inflammasome activation and neuron apoptosis, and might be a promising therapeutic strategy for ischemic stroke.