Research

MicroRNA profiling reveals age dependent differential expression of nuclear factor kappa B and mitogen-activated protein kinase in adipose and bone marrow-derived human mesenchymal stem cells cells

Amitabh C Pandey, Julie Semon, Deepak Kaushal, Regina P O'Sullivan, Julie Glowacki, Jeffery M Gimble and Bruce A Bunnell

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Stem Cell Research & Therapy 2011, 2:49 doi:10.1186/scrt90

Published: 14 December 2011

Abstract (provisional)

Introduction

Mesenchymal stem cells (MSCs) play a central role in mediating endogenous repair of cell and tissue damage. Biological aging is a universal process that results in changes at the cellular and molecular levels. In the present study, the role of microRNA (miRNA) in age-induced molecular changes in MSCs derived from adipose tissue (ASCs) and bone marrow (BMSCs) from young and old human donors were investigated using an unbiased genome-wide approach.

Methods

Human ASCs and BMSCs from young and old donors were cultured and total RNA was isolated. The miRNA fraction was enriched and used to determine the expression profile of miRNA in young and old donor MSCs. Based on miRNA expression, differences in donor MSCs were further investigate utilizing differentiation assays, Western blot, immunocytochemistry, and bioinformatics.

Results

Biological aging demonstrated reduced osteogenic and adipogenic potential in ASCs isolated from older donors, while cell size, complexity and cell surface markers remained intact with aging. Analysis of miRNA profiles revealed that small subsets of active miRNAs changed secondary to aging. Evaluation of miRNA showed significantly decreased levels of gene expression of inhibitory kappa B kinase (IkappaB), interleukin-1alpha, inducible nitric oxide synthase (iNOS), mitogen-activated protein kinase/p38, ERK1/2, c-fos, and c-jun in MSCs from older donors by both bioinformatics and Western blot analysis. Nuclear factor kappa B (NF-kappaB), myc, and interleukin-4 receptor mRNA levels were significantly elevated in aged cells from both the adipose and bone marrow depots. Immunocytochemistry showed nuclear localization in young donors, however, a cytosolic predominance of phosphorylated NF-kappaB in ASCs from older donors. Western blot demonstrated significantly elevated levels of NF-kappaB subunits, p65 and p50, and AKT.

Conclusions

These findings suggest that differential expression of miRNA is an integral component of biological aging in MSCs.