Automated Methods for the Analysis of Skeletal Muscle Fiber Size and Metabolic Type - International Review of Cell and Molecular Biology - page 307

Figure 7.14 Quantification of biomarkers within ragged blue fibers. A skeletal muscle
biopsy from a patient with mitochondrial disease is shown, visualized for SDH
activity (A), TRMU (B), and MyHC- (C). Fibers labeled 1 through 9 are high in SDH-

dehydrogenase activity. Fibers labeled 2, 4, 5, 6, 7, 8, and 9 are examples of

b

“ ragged blue

fibers, which display prominent mitochondrial labeling associated with the fiber bound-

aries. Fibers 1, 2, 3, and 8 are positive for both TRMU and MyHC-

”

b expression.

are reported to preferentially occur in Type I fibers ( Walker and Schon,
1998 ), this biopsy features several examples of ragged blue fibers that are
negative for MyHC- (Type II fibers) (e.g., example cells 4, 5, 6, and 7).

As in the previous example biopsy, some fibers that express TRMU are also
positive for MyHC-

b

b . Furthermore, the fibers that are ragged and express

MyHC- (e.g., cells 2 and 8) also feature TRMU expression. These obser-

vations are consistent with the hypothesis that TRMU may be differentially
expressed by Type I fibers; the degree to which this holds true for healthy
specimens and patients with mitochondrial diseases

b

remains to be

fully elucidated.
These protocols demonstrate a practical advance for the analysis of skeletal
muscle biopsies, since the enzymatic colorimetric assays and fluorescence
determinations of biomarker expression were performed on the same tissue
section. A further goal of this research will be to develop relevant “on-slide”
standard samples, which can be used for more precise quantification of enzy-
matic activity, on a fiber-by-fiber basis, in skeletal muscle specimens.

7.2. Fiber-specific protein expression beyond myosin: Skeletal
muscle protein expression catalogued in the Human
Protein Atlas
The human genome consists of approximately 20,500 protein-coding genes
( Clamp et al., 2007 ). The goal of the Human Protein Atlas project, funded by
the Knut and Alice Wallenberg Foundation, is to assemble an antibody-based