Heme oxygenase-2 is present in the sarcolemma region of skeletal muscle fibers and is non-continuously co-localized with nitric oxide synthase-1.
There is increasing evidence that the heme oxygenase-2 (HO-2)/carbon monoxide (CO) pathway and the nitric oxide synthase (NOS)/nitric oxide (NO) pathway functionally cross-talk. Therefore, we investigated the appearance of HO-2 in mammalian skeletal muscles where NOS-1 is known to be expressed in high quantities. Immunoblotting of rat hind limb extensor muscles extracts revealed a single 36 kDa band demonstrating the existence of HO-2 in skeletal muscle and indicating the monospecifity of the antibody that was applied. Immunohistochemistry on healthy rat extensor hind limb muscles showed that HO-2 is present in satellite cells, endothelial cells of the vascular system, fibrocytes/fibroblasts but also fiber type-independently in extrafusal myofibers either in association with the non-junctional sarcolemma region, or in a subsarcolemmal network or, less prominently, in cross-striated stripes connected to longitudinally running lines. Combined HO-2 immunohistochemistry and NOS-1 histochemistry revealed an apparent co-localization of both molecules only in the non-junctional sarcolemma region of extrafusal type II myofibers outside costameres. In diseased muscles of mdx mice, HO-2 expression was not changed. In patients suffering from Duchenne's muscular dystrophy, it was absent in the sarcolemma region. In conclusion, the HO-2/CO system is present in mammalian skeletal muscle where it is non-continuously co-localized with the NOS-1/NO-system. This finding implicates an optionally functional cross-talk between both gaseous signaling pathways.
Baum
O
O
Department of Anatomy II, University Clinic Benjamin Franklin, Free University of Berlin, Germany.
Feussner
M
M
Richter
H
H
Gossrau
R
R
D000818:Animals; D002384:Catalysis; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012508:Sarcolemma / Q000378:metabolism*; D013737:Testis / Q000378:metabolism
D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D006419:Heme Oxygenase (Decyclizing); C105245:heme oxygenase-2