Biomedical subjects

Isidro Ferrer

Publications and source records attributed to Isidro Ferrer.

40 records · Page 3Linked to original sources

PubMed2003

Signaling of cell death and cell survival following focal cerebral ischemia: life and death struggle in the penumbra.

Focal ischemia by middle cerebral artery occlusion (MCAO) results in necrosis at the infarct core and activation of complex signal pathways for cell death and cell survival in the penumbra. Recent studies have shown activation of the extrinsic and intrinsic pathways of caspase-mediated cell death, as well as activation of the caspase-independent signaling pathway of apoptosis in several paradigms of focal cerebral ischemia by transient MCAO to adult rats and mice. The extrinsic pathway (cell-death receptor pathway) is initiated by activation of the Fas receptor after binding to the Fas ligand (Fas-L); increased Fas and Fas-L expression has been shown following focal ischemia. Moreover, focal ischemia is greatly reduced in mice expressing mutated (nonfunctional) Fas. Increased expression of caspase-1, -3, -8, and -9, and of cleaved caspase-8, has been observed in the penumbra. Activation of the intrinsic (mitochondrial) pathway following focal ischemia is triggered by Bax translocation to and competition with Bcl-2 and other members of the Bcl-2 family in the mitochondria membrane that is followed by cytochrome c release to the cytosol. Bcl-2 over-expression reduces infarct size. Cytochrome c binds to Apaf-1 and dATP and recruits and cleaves pro-caspase-9 in the apoptosome. Both caspase-8 and caspase-9 activate caspase-3, among other caspases, which in turn cleave several crucial substrates, including the DNA-repairing enzyme poly(ADP-ribose) polymerase (PARP), into fragments of 89 and 28 kDa. Inhibition of caspase-3 reduces the infarct size, further supporting caspase-3 activation following transient MCAO. In addition, caspase-8 cleaves Bid, the truncated form of which has the capacity to translocate to the mitochondria and induce cytochrome c release. The volume of brain infarct is greatly reduced in Bid-deficient mice, thus indicating activation of the mitochondrial pathway by cell-death receptors following focal ischemia. Recent studies have shown the mitochondrial release of other factors; Smac/DIABLO (Smac: second mitochondrial activator of caspases: DIABLO: direct IAP binding protein with low pI) binds to and neutralizes the effects of the X-linked inhibitor of apoptosis (XIAP). Finally, apoptosis-inducing factor (AIF) translocates to the mitochondria and the nucleus following focal ischemia and produces peripheral chromatin condensation and large-scale DNA strands, thus leading to the caspase-independent cell death pathway of apoptosis. Delineation of the pro-apoptotic and pro-survival signals in the penumbra may not only increase understanding of the process but also help to rationalize strategies geared to reducing brain damage targeted at the periphery of the infarct core.

Animals↗

PubMed2003

Downregulation of Bcl-2 proteins in type I spinal muscular atrophy motor neurons during fetal development.

Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by mutations in the survival motor neuron gene. The degeneration and loss of the anterior horn cells constitute the major neuropathological finding in SMA, although the mechanism and timing of this abnormal motor neuron death remain unknown. It has recently been reported that the fetal SMA spinal cord shows a significant increase in cells with DNA fragmentation, suggesting that the programmed cell death is aberrantly increased in type I SMA during development. We have analyzed 2 antiapoptotic proteins, Bcl-2 and Bcl-X, by Western blot and immunohistochemistry screening for differential expression in control and SMA fetal spinal cords. Expression of these proteins was found in various neuronal populations and structures of the developing spinal cord. At 15 weeks, motor neurons of SMA fetuses showed a marked decrease in the levels of Bcl-2 and a delay in the expression of Bcl-X in comparison with controls. The difference in the pattern and degree of expression is consistent with a role for both proteins in the aberrant programmed cell death observed in type I SMA.

Anterior Horn Cells↗

PubMed2003

Ubiquitin-negative mini-pick-like bodies in the dentate gyrus in p301l tauopathy.

Neuropathological and biochemical findings are reported in a patient who had suffered from frontotemporal dementia associated with a P310L mutation in the tau gene and included in the H1 haplotype. Tau accumulation, as revealed with phospho-specific anti-tau antibodies Thr181, Ser199, Ser202, Ser214, Ser262, Ser396, Ser422 and AT8 (Ser202 and Thr205), was found in neurons with pre-tangles, and astrocytes and oligodendrocytes through the brain. The most characteristic feature was tau immunoreactivity decorating the perinuclear region and small cytoplasmic aggregates designed as mini-Pick-like bodies, mainly in the dentate gyrus. Inclusions were not stained with anti-ubiquitin antibodies and did not recruit tubulins. Tau accumulation in individual cells was associated with increased expression of kinases linked with tau phosphorylation, mainly active (phosphorylated) stress kinases SAPK/JNK and p38 (SAPK/JNK-P and p38-P). Phosphorylated GSK-3 beta at Ser9 (GSK-3 beta-P), that inactivates the kinase, was particularly abundant in mini-Pick-like bodies, thus suggesting alternative roles of GSK-3 probably involved in cell survival. Western blots of sarkosyl-insoluble fractions revealed a double band pattern of phospho-tau of 68/66 kDa and 64 kDa in the hippocampus and white matter in the P310L mutation. Sarkosyl-insoluble fractions of the hippocampus were enriched in p38-P and GSK-3 beta-P in Alzheimer's disease (AD) cases, processed in parallel for comparative purposes, but not in the P310L mutation. In addition, no bands of high molecular weight were found in P310L in contrast with AD in these fractions. These findings indicate that the major sites of tau phosphorylation, and the expression of kinases involved in tau phosphorylation are active in P310L mutation as in AD and other tauopathies. Yet the P310L mutation has particular phospho-tau inclusions that are not tag with ubiquitin and appear to be rather soluble when compared with AD.

Antibodies, Anti-Idiotypic↗

PubMed2002

Citicoline increases glutathione redox ratio and reduces caspase-3 activation and cell death in staurosporine-treated SH-SY5Y human neuroblastoma cells.

Citicoline, or CDP-choline, is an essential endogenous intermediate in the biosynthesis of phosphatidylcholine that may act as a neuroprotector in several models of neurodegeneration. The present study analyses the effects of citicoline in the paradigm of staurosporine-induced cell death in human SH-SY5Y neuroblastoma cells. Citicoline reduces apoptosis induced by 100 nM staurosporine for 12 h in SH-SY5Y cells. This effect is higher with pre-treatment of 60 mM citicoline for 24 h after staurosporine challenge. Moreover, citicoline treatment restores glutathione redox ratio diminished after staurosporine challenge. Finally, citicoline also reduces the expression levels of active caspase-3 and specific PARP-cleaved products of 89 kDa resulting from staurosporine exposure when citicoline is added to the culture medium 24 h before staurosporine. These findings demonstrate that citicoline affects the staurosporine-induced apoptosis cell-signalling pathway by interacting with the glutathione system and by inhibiting caspase-3 in SH-SY5Y human neuroblastoma cells.

Apoptosis↗