Mesenchymal stem cells protect against TBI-induced pyroptosis in vivo and in vitro through TSG-6

Abstract

Background Pyroptosis, especially microglial pyroptosis, may play an important role in central nervous system pathologies, including traumatic brain injury (TBI). Transplantation of mesenchymal stem cells (MSCs), such as human umbilical cord MSCs (hUMSCs), has been a focus of brain injury treatment. Recently, MSCs have been found to play a role in many diseases by regulating the pyroptosis pathway. However, the effect of MSC transplantation on pyroptosis following TBI remains unknown. Tumor necrosis factor α stimulated gene 6/protein (TSG-6), a potent anti-inflammatory factor expressed in many cell types including MSCs, plays an anti-inflammatory role in many diseases; however, the effect of TSG-6 secreted by MSCs on pyroptosis remains unclear. Methods Mice were subjected to controlled cortical impact injury in vivo. To assess the time course of pyroptosis after TBI, brains of TBI mice were collected at different time points. To study the effect of TSG-6 secreted by hUMSCs in regulating pyroptosis, normal hUMSCs, sh-TSG-6 hUMSCs, or different concentrations of rmTSG-6 were injected intracerebroventricularly into mice 4 h after TBI. Neurological deficits, double immunofluorescence staining, presence of inflammatory factors, cell apoptosis, and pyroptosis were assessed. In vitro, we investigated the anti-pyroptosis effects of hUMSCs and TSG-6 in a lipopolysaccharide/ATP-induced BV2 microglial pyroptosis model. Results In TBI mice, the co-localization of Iba-1 (marking microglia/macrophages) with NLRP3/Caspase-1 p20/GSDMD was distinctly observed at 48 h. In vivo, hUMSC transplantation or treatment with rmTSG-6 in TBI mice significantly improved neurological deficits, reduced inflammatory cytokine expression, and inhibited both NLRP3/Caspase-1 p20/GSDMD expression and microglial pyroptosis in the cerebral cortices of TBI mice. However, the therapeutic effect of hUMSCs on TBI mice was reduced by the inhibition of TSG-6 expression in hUMSCs. In vitro, lipopolysaccharide/ATP-induced BV2 microglial pyroptosis was inhibited by co-culture with hUMSCs or with rmTSG-6. However, the inhibitory effect of hUMSCs on BV2 microglial pyroptosis was significantly reduced by TSG-6-shRNA transfection. Conclusion In TBI mice, microglial pyroptosis was observed. Both in vivo and in vitro, hUMSCs inhibited pyroptosis, particularly microglial pyroptosis, by regulating the NLRP3/Caspase-1/GSDMD signaling pathway via TSG-6.

Targeting pyroptosis with nanoparticles to alleviate neuroinflammatory for preventing secondary damage following traumatic brain injury

“…7A ). The outcomes of our study suggest that pyroptosis increases in the damaged brain following TBI, consistent with the results of numerous studies ( 30 , 47 , 48 ). Therefore, inhibiting pyroptosis in neurons and glial cells following TBI is a potential target for treating secondary brain injury.…”

“…Caspase cleavage of GSDMD, the executioner of pyroptosis, liberates an N-terminal p30 fragment (GSDMD-N), which oligomerizes and forms pores in the plasma membrane. These pores serve as a conduit for the release of IL-1β and IL-18 and, ultimately, the demise of the cell ( 30 ). However, DSF can prevent pyroptosis by inhibiting the formation of GSDMD N-terminal pores on the cell membrane surface, which stops the release of inflammatory cytokines ( Fig.…”

A novel organotypic cortical slice culture model for traumatic brain injury: molecular changes induced by injury and mesenchymal stromal cell secretome treatment

“…In addition, histological analysis revealed an increased number of branches in treated slices, in accordance with previous findings from our group, showing MSC-secretome promotion of axonal outgrowth in primary cultures of rat embryonic hippocampal and cortical neurons, with a major role of BDNF in the observed effects ( Martins et al, 2017 ). MSCs have been shown to induce a microglia protective phenotype ( Zanier et al, 2011 , 2014 ; Pischiutta et al, 2016 , 2022 ; Kota et al, 2017 ; Xu et al, 2020 ) and reduce pyroptosis, a type of programmed cell death associated with inflammatory response ( Feng et al, 2022 ). We found that MSC-secretome promoted microglia activation calling for in-depth analysis of microglia functional state.…”

The Crosstalk between Mesenchymal Stromal/Stem Cells and Hepatocytes in Homeostasis and under Stress

“…Thus, both in liver injuries in vivo and in the course of indirect co-cultivation with hepatocytes subjected to pyroptosis-inducing stress in vitro, MSCs are able to protect hepatocytes from pyroptosis, most likely due to the secreted factors. For example, human UC-MSCs abrogated traumatic brain injury-induced pyroptosis in vivo and lipopolysaccharide/ATPinduced BV2 microglial pyroptosis in vitro due to the secretion of anti-inflammatory factors, such as tumor necrosis factor-stimulated gene 6 (TSG-6) [248]. The inhibition of pyropto-sis in dextran sulfate sodium-induced ulcerative colitis in mice by transplantation of hair follicle-derived MSCs is critically associated with exosomes produced by mesenchymal cells since the inhibition of exosome secretion completely abolishes the protective effects of the MSCs in vivo and in vitro.…”