Burn-induced enhancement of mRNA of lysosomal cathepsins in skeletal muscle
A localized burn injury to a rat hindlimb results in atrophy of soleus muscle (in the absence of cellular damage) which is attributable to an increase in muscle protein breakdown. Previous work has shown that lysosomal enzyme activities (cathepsins B, L, and D) are elevated in muscle from the burned leg by 50% to 100%. Activities are only slightly elevated by 1 day postburn but are maximal by 2 days. Incubation of muscles in the presence of /sup 3/H-mannose show that microsomal glycoprotein synthesis is specifically elevated by 1 day postburn. To determine the cause of the increased protein synthesis, total RNA was extracted from muscles of burned and control legs and electrophoresed in agarose. Northern blots of these samples were hybridized to nick translated cDNA clones which were obtained from several sources. Quantitative analysis of autoradiograms indicated that mRNA of cathepsin B was elevated 5 to 30 fold by one day postburn and remained high during the next two days. Changes in cathepsin D mRNA was less marked. The increased mRNA levels correlate in time with the increased protein synthesis in the microsomal glycoprotein fraction, but precede the increase in cathepsin activity. These results indicate that burns increase the synthesis of lysosomal proteases in skeletal muscle by increasing the level of cathepsin mRNA.
- Research Organization:
- Louisiana State Univ. Medical Center, New Orleans
- OSTI ID:
- 6079440
- Report Number(s):
- CONF-870644-; TRN: 87-037130
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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GLUCOPROTEINS
BIOSYNTHESIS
LIMBS
BURNS
MESSENGER-RNA
MUSCLES
ATROPHY
AUTORADIOGRAPHY
ELECTROPHORESIS
MANNOSE
MICROSOMES
RATS
RNA
TRITIUM COMPOUNDS
ALDEHYDES
ANIMALS
BODY
BODY AREAS
CARBOHYDRATES
CELL CONSTITUENTS
HEXOSES
INJURIES
LABELLED COMPOUNDS
MAMMALS
MONOSACCHARIDES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PATHOLOGICAL CHANGES
PROTEINS
RODENTS
SACCHARIDES
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
550901 - Pathology- Tracer Techniques