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Updated: Jul 11, 2026
Isolation of Intermediate Filament Proteins from Multiple Mouse Tissues to Study Aging-associated Post-translational Modifications
Published on: May 18, 2017
Comparison of the lateral diffusion coefficient of hepatocyte plasma membrane proteins in three strains of
I Zs -Nagy1, S Tanaka, K Kitani
1National Institute for Longevity Sciences (NILS), 36-3, Gengo, Morioka-cho Obu-shi, 474-8522, Aichi, Japan
Abstract:
The lateral diffusion coefficients of proteins (D(p)) were measured in hepatocyte plasma membrane in freshly prepared liver smears by means of the fluorescence recovery after photobleaching (FRAP) method. D(p) was measured after development of peroxide-induced autofluorescence (PIAF) in a total of 115 senescence accelerated mice (SAM), distributed in three strains, at least five age-groups in each, as follows: (i) SAMR1TA (25 males and 22 females), medium life span (MLS) in months, under specific pathogen free (SPF) conditions, MLS(spf) 20.1 and 20.0, respectively, while under conventional conditions, MLS(Deltapf)=18.9 in average for both sexes; (ii) SAMP6/Ta (18 males and 17 females), MLS(spf)=17.1 and 15.3, respectively, and MLS(cc)=8.1 for both sexes; (iii) SAMP6/Ta (17 males and 16 females), MLS(spf)=15.6 and 14.7, respectively, and MLS(cc)=10.0 for both sexes. A highly significant negative linear age-correlation of D(p) (R=0.975 or higher) was found in each strain, being roughly proportional with the MLS(cc) values. Since the studied mice kept under SPF conditions survived longer, than under conventional conditions, the actual age-dependent decay rates of D(p) values did not differ significantly in two pairs of comparisons (female R1/P6 and female R1/P8), whereas they did in all other possible pairs, including also the normal C57BL/6 mice. The main conclusion can be drawn that the D(p) of hepatocyte membranes is a good biomarker of aging and survival also in SAM, as in all other inbred and outbred rodents, studied so far.
Insights
Protein diffusion in liver cells significantly decreases with age in senescence accelerated mice. This finding suggests protein diffusion is a reliable biomarker for aging and survival across various rodent models.
Area of Science:
- Gerontology
- Cell Biology
- Biophysics
Background:
- Cell membrane protein dynamics are crucial for cellular function and can be affected by aging.
- Senescence Accelerated Mice (SAM) models are valuable for studying age-related changes.
- Understanding protein diffusion in hepatocytes provides insights into liver aging.
Purpose of the Study:
- To investigate the relationship between protein lateral diffusion coefficients (D(p)) in hepatocyte plasma membranes and aging in SAM mice.
- To evaluate D(p) as a potential biomarker for aging and survival in different SAM strains and housing conditions.
- To compare age-dependent changes in D(p) between SAM mice and C57BL/6 mice.
Main Methods:
- Utilized fluorescence recovery after photobleaching (FRAP) to measure D(p) in freshly prepared liver smears.
- Employed peroxide-induced autofluorescence (PIAF) for D(p) measurements.
- Studied 115 SAM mice across three strains (SAMR1TA, SAMP6/Ta) and multiple age groups, under specific pathogen-free (SPF) and conventional conditions.
Main Results:
- A highly significant negative linear correlation between D(p) and age (R=0.975 or higher) was observed in all SAM strains.
- D(p) values were roughly proportional to the medium life span (MLS) under conventional conditions.
- Age-dependent decay rates of D(p) showed significant differences between most SAM strain comparisons and with C57BL/6 mice, though not in all SPF comparisons.
Conclusions:
- Lateral diffusion coefficients of proteins in hepatocyte membranes serve as a robust biomarker of aging and survival in SAM mice.
- This finding is consistent with previous studies in other inbred and outbred rodent models.
- D(p) offers a valuable tool for assessing age-related physiological decline in the liver.
