Clearance of p16 Ink4a -positive senescent cells delays ageing-associated disorders Darren J....
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Transcript of Clearance of p16 Ink4a -positive senescent cells delays ageing-associated disorders Darren J....
Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders
Darren J. Baker1,2,3, TobiasWijshake1,4, Tamar Tchkonia3, Nathan K. LeBrasseur3,5, Bennett G. Childs1, Bart van de Sluis4,James L. Kirkland3 & Jan M. van Deursen1,2,3
1 0 N O V E M B E R 2 0 1 1 | VO L 4 7 9 | N AT U R E | 2 3 3
Presented by: Chang chu
Jan.13, 2013
Cellular senescence
mouse embryonic fibroblast
? whether senescent cells are causally implicated in age relatedDysfunction? whether their removal is beneficial
1 http://en.wikipedia.org/wiki/P16_(gene)
P161: Cyclin-dependent kinase inhibitor 2A
multiple tumor suppressor 1 (MTS-1)
Transgenic strategy:
An earlier mouse model : FAT-ATTAC2 (fat apoptosis through targeted activation of caspase )
2 Pajvani, U. B. et al. Fat apoptosis through targeted activation of caspase 8: a new mouse model of inducible and reversible lipoatrophy. Nature Med. 11, 797–803(2005).
Fabp4 promotor
Pronuclear injection of the INK-ATTAC construct into FVB oocytesNine transgenic INK-ATTAC founder lines
• adipose tissue, skeletal muscle and eye
• shortened lifespan age-related phenotypes
BubR1H/H mice
• BubR1 encodes a key member of the mitotic checkpoint
inguinal adipose tissue (IAT)
1. Transgenic INK-ATTAC and endogenous p16Ink4a are under the same transcriptional control mechanism
Rosiglitazone
2. INK-ATTAC is expressed in senescent cells in BubR1 hypomorphic tissue.
SA-b-Gal stained IAT
Expression of senescence markers in tissues
INK-ATTAC is selectively expressed in p16Ink4a-positive senescent cells
3. INK-ATTAC can eliminate senescent cells
• Bone marrow cells of WT;INK-ATTAC transgenic lines 3 and 5
• Cultured with rosiglitazone for 5 days
• Treated with AP20187 for 48h
FKBP–Casp8 activation efficiently eliminates p16Ink4a-positive senescent cells in vitro.
4. Clearance of p16Ink4a-expressing cells from BubR1H/H mice prevents or delays the onset of age-related phenotypes
9-month-old mice
BubR1H/H;INK-ATTAC-3 and -5 mice at 3 weeks of age : AP20187 every third day Untreated
Sarcopenia, cataracts and loss of adipose tissue
Continuous removal of p16Ink4a-expressing cells from BubR1H/H;INK-ATTAC mice selectively delays age-related phenotypes
5. The delayed onset of age-related pathologies coincided with a reduction in the number of senescent cells in these tissues.
Senescent cells were cleared from tissues and that this delays acquisition of age-related dysfunction in BubR1 hypomorphic mice.
BubR1H/H at 5 months: age-related phenotypes are apparentAP20187 treatmentMeasured p16Ink4a-dependent age-related phenotypes at 10 months
6.Investigating the effect of senescent cell clearance later in life
Senescence markers were substantially reduced
Late-life clearance of p16Ink4a positive senescent cells attenuates progression of age-related decline rather than a reversal of ageing in BubR1 hypomorphic mice.
• A novel transgenic mouse model
• Both life-long and late-life clearance of the p16Ink4a expressing senescent cells selectively delayed age-related pathologies in tissues that accumulate these cells.
• Therapeutic interventions to clear senescent cells or block their effects may represent an avenue for treating or delaying age-related diseases and improving healthy human lifespan.