Subarachnoid hemorrhage (SAH) is a form of
stroke associated with high mortality and morbidity. Despite advances in treatment for SAH, the prognosis remains poor. We have previously demonstrated that
glycine, a non-
essential amino acid is involved in neuroprotection following
intracerebral hemorrhage via the
Phosphatase and
tensin homolog (
PTEN)/protein kinase B (AKT) signaling pathway. However, whether it has a role in inducing neuroprotection in SAH is not known. The present study was designed to investigate the role of
glycine in SAH. In this study, we show that
glycine can reduce
brain edema and protect neurons in SAH via a novel pathway. Following a hemorrhagic episode, there is evidence of downregulation of S473 phosphorylation of AKT (p-AKT), and this can be reversed with
glycine treatment. We also found that administration of
glycine can reduce neuronal cell death in SAH by activating the AKT pathway.
Glycine was shown to upregulate miRNA-26b, which led to PTEN downregulation followed by AKT activation, resulting in inhibition of neuronal death. Inhibition of miRNA-26b, PTEN or AKT activation suppressed the
neuroprotective effects of
glycine.
Glycine treatment also suppressed SAH-induced M1 microglial polarization and thereby
inflammation. Taken together, we conclude that
glycine has
neuroprotective effects in SAH and is mediated by the
miRNA-26b/PTEN/AKT signaling pathway, which may be a therapeutic target for treatment of SAH injury.