Iron dyshomeostasis and mitochondrial impairments are both vitally important for the progression of many neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. Nevertheless, how these two pathological phenomena are linked with one another remains unclear, especially in neurons. To address the question, a model of iron overload was established with exposure of rat primary cortical neurons to excessive iron. We first verified that iron overload resulted in a decrease in adenosine triphosphate (ATP) production in neurons. Meanwhile, the release of mitochondrial cytochrome c was significantly increased after iron overload and consequently triggered an apoptosis signal, as revealed by Caspase 3 cleavage. To explore the potential underlying molecular mechanisms, an unlabeled quantitative proteomics approach was applied to primary neurons. Gene Ontology enrichment analysis revealed that 58 mitochondria‐associated proteins were significantly altered, including three subunits of mitochondrial complex I and optic atrophy 1(OPA1). Increased NADH‐ubiquinone oxidoreductase 75 kDa subunit and decreased NADH‐ubiquinone oxidoreductase subunit A10 levels were further validated by a western blot, and more importantly, complex I activity markedly declined. Iron‐induced down‐regulation on the OPA1 level was also validated by a western blot, which was not reversed by the anti‐oxidant but was reversed by the iron chelator. Moreover, an OPA1‐associated key downstream effect, mitochondrial fragmentation, was found to be aggravated in neurons exposed to excessive iron, which is consistent with the down‐regulation of OPA1. Furthermore, the protein level of PTEN‐induced putative kinase 1, an important protein closely related to complex I activity and mitochondrial fragmentation, also significantly declined in neurons by iron overload. Thus, our findings may shed new light on the linkage between iron toxicity and mitochondrial impairments, such as energy supply deficiency and mitochondrial fragmentation, and further expand the toxic repertoire of iron in the central nerve system. Cover Image for this issue: doi: .

Despite the intense efforts in searching for stroke therapies, an urgent need still exists to explore novel neuroprotective agents for ischemic stroke that have high efficacy and wide therapeutic time-window. Here, we provide the first demonstration that 28-O-caffeoyl betulin (B-CA), a novel derivative of naturally occurring caffeoyl triterpene, could significantly alleviate brain infarction and neurological deficit when given as late as 6 h after transient middle cerebral artery occlusion in the rat. Moreover, post-ischemia B-CA administration exhibited long-term (14 days post stroke) protective effects on both brain infarction and functional (i.e., motor and sensory) deficits. Protective B-CA effects correlated with decreased inflammatory responses as indicated by inhibition of microglia and astrocyte activation [stained with ionized calcium-binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) antibody, respectively], as well as suppression of tumor necrosis factor-a, interleukin-1b, and cyclooxygenase-2 overproduction in the ipsilateral cortex of ischemic rat. B-CA administration caused significant hypothermia in the focal cerebral ischemic rat, which may contribute to its ameliorative effects on brain damage and inflammation. In view of its potency in wide therapeutic time-window, robust anti-inflammatory and hypothermic effects, this novel caffeoyl triterpene derivative may lead toward the development of effective therapeutic strategies for the treatment of ischemic stroke. Keywords: caffeoyl triterpene, hypothermia, inflammation, ischemic stroke, neuroprotection, therapeutic time window. Ischemic stroke is one of the leading causes of morbidity and mortality in the world (Go et al. 2014). Currently, the only US Food and Drug Administration-approved acute intervention for ischemic stroke is thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA). Although rt-PA treatment can provide acute recanalization and improves functional outcome post stroke, it has a narrow therapeutic time window of < 4.5 h post stroke with risk of hemorrhage and may exacerbate the cerebral injury (Fonarow et al. 2011). While on the other hand, the neuroprotective approach has gained increasing attention and considered as a promising alternative treatment for ischemic stroke (Schmidt Abbreviations used: B-CA, 28-O-caffeoyl betulin; COX-2, cyclooxygenase-2; ERK, extracellular regulated protein kinases; GFAP, glial fibrillary acidic protein; Iba-1, ionized calcium-binding adapter molecule 1; IL-1b, interleukin-1b; IL-6, interleukin-6; MCAO, middle cerebral artery occlusion; MMP-9, matrix metallopeptidase 9; mNSS, modified neurological severity score; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide; OGD, oxygen and glucose deprivation; PSD-95, postsynaptic density 95; rCBF, regional cerebral blood flow; rt-PA, recombinant tissue plasminogen activator; TNF-a, tumor necrosis factor-a; TRPV1, the transient receptor potential cation channel subfamily V member 1; TTC, tri...

(1) Huperzine A, a promising therapeutic agent for Alzheimer's disease (AD), was tested for its effects on cholinergic and monoaminergic dysfunction induced by injecting beta-amyloid peptide-(1-40) into nucleus basalis magnocellularis of the rat. (2) Bilateral injection of 10 microg beta-amyloid peptide-(1-40) into nucleus basalis magnocellularis produced local deposits of amyloid plaque and functional abnormalities detected by microdialysis. In medial prefrontal cortex, reductions in the basal levels and stimulated release of acetylcholine, dopamine, norepinephrine, and 5-hydroxytryptamine were observed. However, oral huperzine A (0.18 mg/kg, once daily for 21 consecutive days) markedly reduced morphologic abnormalities at the injection site in rats infused with beta-amyloid peptide-(1-40). Likewise, this treatment ameliorated the beta-amyloid peptide-(1-40)-induced deficits in extracellular acetylcholine, dopamine, and norepinephrine (though not 5-hydroxytryptamine) in medial prefrontal cortex, and lessened the reduction in nicotine or methoctramine-stimulated release of acetylcholine and K(+)-evoked releases of acetylcholine and dopamine. (3) The present results provide the first direct evidence that huperzine A acts to oppose neurotoxic effects of beta-amyloid peptide on cholinergic, dopaminergic, and noradrenergic systems of the rat forebrain.