Gene expression profiling of fibroblasts from a human progeroid disease (mandibuloacral dysplasia, MAD #248370) through cDNA microarrays

Abstract

Mandibuloacral dysplasia (MAD) is a rare autosomal recessive disorder caused basically by a missense mutation within the LMNA gene, which encodes for lamin A/C. We have used gene expression profiling to characterize the specificity of molecular changes induced by the prevalent MAD mutation (R527H). A total of 5531 transcripts expressed in human dermis were investigated in two MAD patients, both carrying the R527H mutation, and three control subjects (age and sex matched). Transcription profiles revealed a differential expression in MAD vs. control fibroblasts in at least 1992 genes. Sixty-seven of these genes showed a common altered pattern in both patients with a threshold expression level >+/-2. Nevertheless, a large number of these genes (43.3%) are ESTs or encode for protein with unknown function; the other genes are involved in biological processes or pathways such as cell adhesion, cell cycle, cellular metabolism, and transcription. Quantitative RT-PCR was applied to validate the microarray results (R2= 0.76). Analysis of the effect of the prevalent MAD mutation (R527H) over the transcriptional pattern of genes expressed in the human dermis showed that this LMNA gene mutation has pleiotropic effects on a limited number of genes. Further characterization of these effects might contribute to understanding the molecular pathogenesis of this disorder.

Figure 1

(A) Underexpressed genes and (B) overexpressed genes in MAD fibroblasts are grouped according to the biological process in which they are involved or to their molecular function.

Figure 2

Comparison between data obtained from microarray and QRT-PCR experiments (expressed as log2 of the ratio values). The microarray and the QRT-PCR values for each gene are the average value of those obtained independently by the two MAD patients. The positive correlation between the two sets of data is statistically significant (p = 0.001).

Figure 3

Histogram representing the expression levels (ΔC _T, see Materials and Methods) obtained by QRT-PCR of six differentially expressed genes in MAD patients and control subjects.