Transplantation of neural stem cells (NSCs) has been proposed as a promising therapeutic strategy for the treatment of ischemia/reperfusion (I/R)-induced brain injury. However, existing evidence has also challenged this therapy on its limitations, such as the difficulty for stem cells to survive after transplantation due to the unfavorable microenvironment in the ischemic brain. Herein, we have investigated whether preconditioning of NSCs with adjudin, a small molecule compound, could enhance their survivability and further improve the therapeutic effect for NSC-based stroke therapy.We aimed to examine the effect of adjudin pretreatment on NSCs by measuring a panel of parameters after their transplantation into the infarct area of ipsilateral striatum 24 hours after I/R in mice.We found that pretreatment of NSCs with adjudin could enhance the viability of NSCs after their transplantation into the stroke-induced infarct area. Compared with the untreated NSC group, the adjudin-preconditioned group showed decreased infarct volume and neurobehavioral deficiency through ameliorating blood–brain barrier disruption and promoting the expression and secretion of brain-derived neurotrophic factor. We also employed H2O2-induced cell death model in vitro and found that adjudin preconditioning could promote NSC survival through inhibition of oxidative stress and activation of Akt signaling pathway.This study showed that adjudin could be used to precondition NSCs to enhance their survivability and improve recovery in the stroke model, unveiling the value of adjudin for stem cell-based stroke therapy.

SIRT6 is a NAD+-dependent histone deacetylase and has been implicated in the regulation of genomic stability, DNA repair, metabolic homeostasis and several diseases. The effect of SIRT6 in cerebral ischemia and oxygen/glucose deprivation (OGD) has been reported, however the role of SIRT6 in oxidative stress damage remains unclear. Here we used SH-SY5Y neuronal cells and found that overexpression of SIRT6 led to decreased cell viability and increased necrotic cell death and reactive oxygen species (ROS) production under oxidative stress. Mechanistic study revealed that SIRT6 induced autophagy via attenuation of AKT signaling and treatment with autophagy inhibitor 3-MA or knockdown of autophagy-related protein Atg5 rescued H2O2-induced neuronal injury. Conversely, SIRT6 inhibition suppressed autophagy and reduced oxidative stress-induced neuronal damage. These results suggest that SIRT6 might be a potential therapeutic target for neuroprotection.

Sirtuins are a family of nicotinamide adenine dinucleotide (NAD+) dependent deacetylases involved in multiple biological functions including metabolism, inflammation, stress resistance and aging. In mammals, there are seven members (Sirt1—Sirt7), with diversities in their subcellular localizations and enzymatic activities. Here, we review the functions of sirtuins, with a focus on their roles in normal brain physiology such as neural development regulation, body homeostasis maintenance, and memory formation. We also discuss the role of sirtuins in a variety of brain diseases including stroke, Alzheimer’s, Parkinson’s, and motor neuron dysfunction. Because of the emerging functions of sirtuins in brain physiology and pathology, drugs targeting sirtuins may offer potential therapeutic values for brain disorders.

SIRT6 is an important histone modifying protein that regulates DNA repair, telomere maintenance, energy metabolism, and target gene expression. Recently SIRT6 has been identified as a tumor suppressor and is down-regulated in certain cancer types, but not in other cancers. From deposited gene profiling studies we found that SIRT6 was overexpressed in prostate tumors, compared with normal or paratumor prostate tissues. Tissue micro-array studies confirmed the higher levels of SIRT6 in both prostate tumor tissues and prostate cancer cells than in their normal counterparts. Knockdown of SIRT6 in human prostate cancer cells led to sub-G1 phase arrest of cell cycle, increased apoptosis, elevated DNA damage level and decrease in BCL2 gene expression. Moreover, SIRT6-de-ficiency reduced cell viability and enhanced chemotherapeutics sensitivity. Taken together, this study provides the first evidence of SIRT6 overexpression in human prostate cancer, and SIRT6 regulation could be exploited for prostate cancer therapy.

Adjudin was originally developed as an improved analog of lonidamine to serve as a non-hormonal reversible male contraceptive that could cause exfoliation of the immature sperms from the seminiferous epithelium. Recently, the functionality spectrum of adjudin expands beyond as an anti-spermatogenic agent, namely, it could function as an anti-cancer drug potentially useful for combination chemotherapy, and as an anti-inflammatory molecule that could protect against ischemic stroke injury. Most strikingly, adjudin acts through activation of mitochondrion-located Sirt3 to safeguard hair cells of the cochlea from ototoxicant such as gentamycin. Recent studies also indicate that adjudin could attenuate oxidative stress and cellular senescence. These findings suggest wider applications of this small molecule, particularly in aging-related diseases.

Neuroinflammation caused by microglial activation plays a key role in ischemia, neurodegeneration and many other CNS diseases. In this study, we found that Adjudin, a potential non-hormonal male contraceptive, exhibits additional function to reduce the production of proinflammatory mediators. Adjudin significantly inhibited LPS-induced IL-6 release and IL-6, IL-1β, TNF-α expression in BV2 microglial cells. Furthermore, Adjudin exhibited anti-inflammatory properties by suppression of NF-κB p65 nuclear translocation and DNA binding activity as well as ERK MAPK phosphorylation. To determine the in vivo effect of Adjudin, we used a permanent middle cerebral artery occlusion (pMCAO) mouse model and found that Adjudin could reduce ischemia-induced CD11b expression, a marker of microglial activation. Furthermore, Adjudin treatment attenuated brain edema and neurological deficits after ischemia but did not reduce infarct volume. Thus, our data suggest that Adjudin may be useful for mitigating neuroinflammation.