Targeting mitophagy in Parkinson's disease.

The genetics and pathophysiology of Parkinson's disease (PD) strongly implicate mitochondria in disease aetiology. Elegant studies over the last two decades have elucidated complex molecular signaling governing the identification and removal of dysfunctional mitochondria from the cell, a process of mitochondrial quality control known as mitophagy. Mitochondrial deficits and specifically reduced mitophagy are evident in both sporadic and familial PD.

Direct Evidence of the Presence of Cross-Linked Aβ Dimers in the Brains of Alzheimer's Disease Patients.

Brain-derived amyloid-β (Aβ) dimers are associated with Alzheimer's disease (AD). However, their covalent nature remains controversial. This feature is relevant, as a covalent cross-link has been proposed to make brain-derived dimers (brain dimers) more synaptotoxic than Aβ monomers and would also make them suitable candidates for biomarker development.

Evaluation of hypoxia inducible factor expression in inflammatory and neurodegenerative brain models.

The neuroinflammatory process is thought to contribute to the progression of neurological disorders and brain pathologies. The release of pro-inflammatory cytokines and chemokines by activated glial cells, astrocytes and microglia plays an important role in this process. However, the role of hypoxia-inducible factor-1α (HIF-1α), the key transcription factor regulating the expression of hypoxia-inducible genes, during glial activation is less known.

PI3 k/akt inhibition induces apoptosis through p38 activation in neurons.

Accumulating evidence suggests that the PI3K/AKT pathway is a pro-survival signalling system in neurons. Therefore, the inhibition of this pathway may be implicated in the degeneration of neurons in Parkinson's disease (PD), Alzheimer's disease (AD), and other neurological disorders. Here we study the participation of the mitogen-activated protein kinase (MAPK) pathway on apoptosis induced by PI3K/AKT inhibition in cultured cerebellar granule cells (CGCs).

GSK3β inhibition is involved in the neuroprotective effects of cyclin-dependent kinase inhibitors in neurons.

In the present study, we evaluated the effects of roscovitine (Rosco) and flavopiridol (Flavo), both of which are classified as cyclin-dependent kinase (CDK) inhibitors, on apoptosis induced by the inhibition of PI3K/AKT pathway in cerebellar granule neurons (CGNs). Our results demonstrate that both CDK inhibitors prevented apoptosis induced by LY294002 (LY), as also occurs with SB415286 (SB4), a selective GSK3β inhibitor. Our findings also indicate that these CDK inhibitors inhibit GSK3β, representing a potential pharmacological mechanism involved in their neuroprotective properties.

Study of the pathways involved in apoptosis induced by PI3K inhibition in cerebellar granule neurons.

In the present study we focused in the PI3K/Akt pathway which plays a key role in neuronal survival. Here we show that inhibition of PI3K/Akt by means of LY294002 induces apoptosis via a caspase-dependent and calpain-independent pathway in cerebellar granule neurons (CGNs). This finding was confirmed using zVAD-fmk, a widely caspase inhibitor that prevents apoptosis.

Prosurvival role of JAK/STAT and Akt signaling pathways in MPP+-induced apoptosis in neurons.

In the present study the role of JAK/STAT and Akt in apoptosis was evaluated in cerebellar granule cells after treatment with the mitochondrial toxin MPP(+). Firstly, we evaluated the role of the prosurvival Akt pathway in MPP(+)-induced apoptosis and found that MPP(+) rapidly reduced the phosphorylation of Akt at Ser473. Since PTEN is an upstream regulator of Akt, its inhibition with bpV(pic) (1-30 μM) should activate Akt, however, it did not attenuate CGC cell death mediated by MPP(+) but protected CGC from apoptosis mediated by S/K deprivation.

Activation of ataxia telangiectasia muted under experimental models and human Parkinson's disease.

In the present study we demonstrated that neurotoxin MPP(+)-induced DNA damage is followed by ataxia telangiectasia muted (ATM) activation either in cerebellar granule cells (CGC) or in B65 cell line. In CGC, the selective ATM inhibitor KU-55933 showed neuroprotective effects against MPP(+)-induced neuronal cell loss and apoptosis, lending support to the key role of ATM in experimental models of Parkinson's disease. Likewise, we showed that knockdown of ATM levels in neuroblastoma B65 cells using an ATM-specific siRNA attenuates the phosphorylation of retinoblastoma protein without affecting other cell-cycle proteins involved in the G(0)/G(1) cell-cycle phase.

ATM is involved in cell-cycle control through the regulation of retinoblastoma protein phosphorylation.

Ataxia telangiectasia mutated protein (ATM) is a member of the phosphatidylinositol-3 kinase (PI3K) family, which has a role in the cellular response to DNA double-strand breaks (DSBs). In the present study, we evaluated the role of ATM in cell-cycle control in dopaminergic rat neuroblastoma B65 cells. For this purpose, ATM activity was either inhibited pharmacologically with the specific inhibitor KU-55933, or the ATM gene was partially silenced by transfection with small interfering RNA (siRNA).

Oxidative stress-induced DNA damage and cell cycle regulation in B65 dopaminergic cell line.

Reactive oxygen species and oxidative stress are associated with neuronal cell death in many neurodegenerative conditions. However, the exact molecular mechanisms triggered by oxidative stress in neurodegeneration are still unclear. This study used the B65 rat neuroblastoma cell line as a model to study the molecular events that occur after H(2)O(2) treatment.