Abstract WP104: Neuron- microglia Crosstalk Mediated by Soluble Fas Ligand after Ischemic Stroke

Objectives: Accumulating data indicate that soluble Fas Ligand (sFasL) is involved in inflammatory cascades after cerebral ischemia. However, the potential role of sFasL in modulating the neuron-microglia crosstalk is barely understood. We hypothesized that sFasL triggers neuronal death and M1-microglia polarization after ischemic injury. Methods: Middle cerebral artery occlusion (MCAO) was induced in both FasL mutant gld mice and wild-type C57BL/6J mice. Microglial polarization was determined by immunohistochemical staining and real-time polymerase chain reaction. Expression of sFasL was detected by western blot. The expression of sFasL in the medium after OGD was detected by ELISA assay. Activity of sFasL was blocked by using its neutralizing antibody. Neuronal survival and apoptosis were quantified. Results: Expression of sFasL at protein level in the ischemic cortex was increased by 451.67% in wild-type stroke mice over the sham-operated brain. The gld mice demonstrated attenuated neuronal death and M1-microglial phenotype markers (iNOS and CD86) compared to wild-type mice after MCAO. Protein expression of sFasL was increased both in the neuronal and microglial culture medium after OGD. In addition, conditioned medium obtained from ischemic neuron drove microglial polarization toward the M1 phenotype producing more pro-inflammatory cytokines (IL-1β, TNF-α and MCP-1). Meanwhile, conditioned medium from ischemic microglia exacerbated neuronal death dramatically. sFasL neutralizing antibody, however, significantly decreased these changes. Furthermore, phosphorylated JAK2/STAT3(Y705 and S727) was increased in microglia after neuronal-conditioned medium treatment, which was decreased following inhibition of sFasL activity. Conclusions: The gld mice demonstrated attenuated ischemic brain damage. sFasL is involved in modulating the crosstalk between these two cells in a contact-independent way. Microglia-released sFasL exacerbated neuronal death while neuron-released sFasL induced M1-microglia polarization after ischemic stroke. Neutralization of sFasL, thereby, may protect against ischemic brain damage and provide novel views on post-stroke neuroimmune regulation.

Download Full-text

The bioactivity of soluble Fas ligand is modulated by key amino acids of its stalk region

PLoS ONE ◽

10.1371/journal.pone.0253260 ◽

2021 ◽

Vol 16 (6) ◽

pp. e0253260

Author(s):

Osamu Kajikawa ◽

Raquel Herrero ◽

Yu-Hua Chow ◽

Chi F. Hung ◽

Gustavo Matute-Bello

Keyword(s):

Amino Acids ◽

Amino Acid ◽

T Cell ◽

Epithelial Cells ◽

Cell Line ◽

Fas Ligand ◽

Wild Type ◽

Soluble Fas ◽

Charged Amino Acids ◽

Soluble Fas Ligand

We have previously reported that the 26-amino acid N-terminus stalk region of soluble Fas ligand (sFasL), which is separate from its binding site, is required for its biological function. Here we investigate the mechanisms that link the structure of the sFasL stalk region with its function. Using site-directed mutagenesis we cloned a mutant form of sFasL in which all the charged amino acids of the stalk region were changed to neutral alanines (mut-sFasL). We used the Fas-sensitive Jurkat T-cell line and mouse and human alveolar epithelial cells to test the bioactivity of sFasL complexes, using caspase-3 activity and Annexin-V externalization as readouts. Finally, we tested the effects of mut-sFasL on lipopolysaccharide-induced lung injury in mice. We found that mutation of all the 8 charged amino acids of the stalk region into the non-charged amino acid alanine (mut-sFasL) resulted in reduced apoptotic activity compared to wild type sFasL (WT-sFasL). The mut-sFasL attenuated WT-sFasL function on the Fas-sensitive human T-cell line Jurkat and on primary human small airway epithelial cells. The inhibitory mechanism was associated with the formation of complexes of mut-sFasL with the WT protein. Intratracheal administration of the mut-sFasL to mice 24 hours after intratracheal Escherichia coli lipopolysaccharide resulted in attenuation of the inflammatory response 24 hours later. Therefore, the stalk region of sFasL has a critical role on bioactivity, and changes in the structure of the stalk region can result in mutant variants that interfere with the wild type protein function in vitro and in vivo.

Download Full-text

Neuronal Soluble Fas Ligand Drives M1-Microglia Polarization after Cerebral Ischemia

CNS Neuroscience & Therapeutics ◽

10.1111/cns.12575 ◽

2016 ◽

Vol 22 (9) ◽

pp. 771-781 ◽

Cited By ~ 32

Author(s):

Hai-Lan Meng ◽

Xiao-Xi Li ◽

Yan-Ting Chen ◽

Lin-Jie Yu ◽

He Zhang ◽

...

Keyword(s):

Cerebral Ischemia ◽

Fas Ligand ◽

Soluble Fas ◽

Microglia Polarization ◽

Soluble Fas Ligand

Download Full-text

Levels of soluble Fas ligand in myocarditis

The American Journal of Cardiology ◽

10.1016/s0002-9149(98)00300-2 ◽

1998 ◽

Vol 82 (2) ◽

pp. 246-248 ◽

Cited By ~ 47

Author(s):

Tetsuya Toyozaki ◽

Michiaki Hiroe ◽

Masato Tanaka ◽

Shigekazu Nagata ◽

Hidemi Ohwada ◽

...

Keyword(s):

Fas Ligand ◽

Soluble Fas ◽

Soluble Fas Ligand

Download Full-text

Soluble fas ligand levels during rejection after paediatric liver transplantation

Journal of Hepatology ◽

10.1016/s0168-8278(98)80469-8 ◽

1998 ◽

Vol 28 ◽

pp. 67

Author(s):

N. Hadzic ◽

M. Hussain ◽

P. Cheeseman ◽

R. Francavilla ◽

G. Mieli-Vergani ◽

...

Keyword(s):

Liver Transplantation ◽

Fas Ligand ◽

Soluble Fas ◽

Soluble Fas Ligand ◽

Paediatric Liver Transplantation

Download Full-text

Plasma soluble Fas ligand concentration: Decrease in elderly men and increase in patients with gastric carcinoma

Oncology Reports ◽

10.3892/or.8.2.311 ◽

2001 ◽

Cited By ~ 1

Author(s):

Takashi Ichikura ◽

Takashi Majima ◽

Takefumi Uchida ◽

Eiji Okura ◽

Toshiya Ogawa ◽

...

Keyword(s):

Gastric Carcinoma ◽

Fas Ligand ◽

Ligand Concentration ◽

Elderly Men ◽

Soluble Fas ◽

Soluble Fas Ligand

Download Full-text

Plasma Soluble Fas and Soluble Fas Ligand in ChronicGlomerulo nephritis

Nephron ◽

10.1159/000045159 ◽

1998 ◽

Vol 80 (2) ◽

pp. 153-161 ◽

Cited By ~ 15

Author(s):

Hirotake Sano ◽

Kiyoji Asano ◽

Shinya Minatoguchi ◽

Jitsuko Hiraoka ◽

Koh Fujisawa ◽

...

Keyword(s):

Fas Ligand ◽

Soluble Fas ◽

Soluble Fas Ligand

Download Full-text

Circulating Plasma Gelsolin: A Predictor of Favorable Clinical Outcomes in Head and Neck Cancer and Sensitive Biomarker for Early Disease Diagnosis Combined with Soluble Fas Ligand

Cancers ◽

10.3390/cancers12061569 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1569

Author(s):

Chen-Tzu Chiu ◽

Pei-Wen Wang ◽

Meshach Asare-Werehene ◽

Benjamin K. Tsang ◽

Dar-Bin Shieh

Keyword(s):

Head And Neck Cancer ◽

Head And Neck ◽

Clinical Outcomes ◽

Fas Ligand ◽

Healthy Controls ◽

Early Disease ◽

Plasma Gelsolin ◽

Early Disease Detection ◽

Soluble Fas ◽

Soluble Fas Ligand

Head and neck cancer (HNC) accounts for more than 330,000 cancer deaths annually worldwide. Despite late diagnosis being a major factor contributing to HNC mortality, no satisfactory biomarkers exist for early disease detection. Cytoplasmic gelsolin (cGSN) was discovered to predict disease progression in HNC and other malignancies, and circulating plasma gelsolin (pGSN) levels are significantly correlated with infectious and inflammatory disease prognoses. Here, the plasma levels of five candidate biomarkers (circulating pGSN, squamous cell carcinoma antigen, cytokeratin 19 fragment, soluble Fas, and soluble Fas ligand (sFasL)) in 202 patients with HNC and 45 healthy controls were measured using enzyme-linked immunosorbent assay or Millipore cancer multiplex assay. The results demonstrated that circulating pGSN levels were significantly lower in patients with HNC than in healthy controls. Moreover, circulating pGSN outperformed other candidate biomarkers as an independent diagnostic biomarker of HNC in both sensitivity (82.7%) and specificity (95.6%). Receiver operating characteristic curves indicated that combined pGSN and sFasL levels further augmented this sensitivity (90.6%) for early disease detection. Moreover, higher pGSN levels predicted improved prognosis at both 5-year overall survival and progression-free survival. In conclusion, circulating pGSN could be an independent predictor of favorable clinical outcomes and a novel biomarker for the early HNC detection in combination with sFasL.

Download Full-text