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Insulin promotes survival of amyloid-beta oligomers neuroblastoma damaged cells via caspase 9 inhibition and Hsp70 upregulation.

Di Carlo M, Picone P, Carrotta R, Giacomazza D, San Biagio PL - J. Biomed. Biotechnol. (2010)

Bottom Line: By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation.Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program.Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD.

View Article: PubMed Central - PubMed

Affiliation: Istituto di Biomedicina e Immunologia Molecolare A. Monroy, Consiglio Nazionale delle Ricerche, 90146 Palermo, Italy. di-carlo@ibim.cnr.it

ABSTRACT
Alzheimer's disease (AD) and type 2 diabetes are connected in a way that is still not completely understood, but insulin resistance has been implicated as a risk factor for developing AD. Here we show an evidence that insulin is capable of reducing cytotoxicity induced by Amyloid-beta peptides (A-beta) in its oligomeric form in a dose-dependent manner. By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation. A protective role of insulin on mitochondrial damage is also shown by using Mito-red vital dye. Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program. Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD.

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Related in: MedlinePlus

Protective effect of insulin against rAβ42 oligomers induced apoptosis. LAN5 untreated cells as control (a), treated with rAβ42 oligomers (40 μM) for 1 h  (b), with rAβ42 (40 μM) for 1 h and with insulin (100 μM) for 20 h  (c), insulin alone (100 μM) for 20 h (d) were fixed and put through TUNEL assay. Bar 20 μm.
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fig2: Protective effect of insulin against rAβ42 oligomers induced apoptosis. LAN5 untreated cells as control (a), treated with rAβ42 oligomers (40 μM) for 1 h (b), with rAβ42 (40 μM) for 1 h and with insulin (100 μM) for 20 h (c), insulin alone (100 μM) for 20 h (d) were fixed and put through TUNEL assay. Bar 20 μm.

Mentions: In apoptosis a biochemical cascade activates proteases that destroy biomolecules required for cell survival. During this process the cytoplasm condenses, organelles aggregate, chromatin condenses, and nucleus fragments [16]. After cell treatment with rAβ42 oligomers, we detected in the survived cells morphological modifications, typical hallmarks of the apoptosis process. In particular granules, resembling apoptotic bodies, were observable (data not shown). To investigate if insulin can revert this effect, LAN5 cells were put through to the TUNEL assay after treatment with oligomers alone or with oligomers and insulin. An intense brown nuclear staining is visible in the cells treated with rAβ42 (Figure 2(b)), indicating that the apoptotic process has been triggered, whereas no staining is detectable in the cells treated with oligomers and insulin (Figure 2(c)), as seen for the control cells (Figures 2(a) and 2(d)).


Insulin promotes survival of amyloid-beta oligomers neuroblastoma damaged cells via caspase 9 inhibition and Hsp70 upregulation.

Di Carlo M, Picone P, Carrotta R, Giacomazza D, San Biagio PL - J. Biomed. Biotechnol. (2010)

Protective effect of insulin against rAβ42 oligomers induced apoptosis. LAN5 untreated cells as control (a), treated with rAβ42 oligomers (40 μM) for 1 h  (b), with rAβ42 (40 μM) for 1 h and with insulin (100 μM) for 20 h  (c), insulin alone (100 μM) for 20 h (d) were fixed and put through TUNEL assay. Bar 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2871552&req=5

fig2: Protective effect of insulin against rAβ42 oligomers induced apoptosis. LAN5 untreated cells as control (a), treated with rAβ42 oligomers (40 μM) for 1 h (b), with rAβ42 (40 μM) for 1 h and with insulin (100 μM) for 20 h (c), insulin alone (100 μM) for 20 h (d) were fixed and put through TUNEL assay. Bar 20 μm.
Mentions: In apoptosis a biochemical cascade activates proteases that destroy biomolecules required for cell survival. During this process the cytoplasm condenses, organelles aggregate, chromatin condenses, and nucleus fragments [16]. After cell treatment with rAβ42 oligomers, we detected in the survived cells morphological modifications, typical hallmarks of the apoptosis process. In particular granules, resembling apoptotic bodies, were observable (data not shown). To investigate if insulin can revert this effect, LAN5 cells were put through to the TUNEL assay after treatment with oligomers alone or with oligomers and insulin. An intense brown nuclear staining is visible in the cells treated with rAβ42 (Figure 2(b)), indicating that the apoptotic process has been triggered, whereas no staining is detectable in the cells treated with oligomers and insulin (Figure 2(c)), as seen for the control cells (Figures 2(a) and 2(d)).

Bottom Line: By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation.Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program.Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD.

View Article: PubMed Central - PubMed

Affiliation: Istituto di Biomedicina e Immunologia Molecolare A. Monroy, Consiglio Nazionale delle Ricerche, 90146 Palermo, Italy. di-carlo@ibim.cnr.it

ABSTRACT
Alzheimer's disease (AD) and type 2 diabetes are connected in a way that is still not completely understood, but insulin resistance has been implicated as a risk factor for developing AD. Here we show an evidence that insulin is capable of reducing cytotoxicity induced by Amyloid-beta peptides (A-beta) in its oligomeric form in a dose-dependent manner. By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation. A protective role of insulin on mitochondrial damage is also shown by using Mito-red vital dye. Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program. Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD.

Show MeSH
Related in: MedlinePlus