Forced MyHCIIB expression following targeted genetic manipulation of conditionally immortalized muscle precursor cells

Δ-9,11 modification of glucocorticoids dissociates nuclear factor-κB inhibitory efficacy from glucocorticoid response element-associated side effects

Glucocorticoids are standard of care for many inflammatory conditions, but chronic use is associated with a broad array of side effects. This has led to a search for dissociative glucocorticoids--drugs able to retain or improve efficacy associated with transrepression [nuclear factor-κB (NF-κB) inhibition] but with the loss of side effects associated with transactivation (receptor-mediated transcriptional activation through glucocorticoid response element gene promoter elements). We investigated a glucocorticoid derivative with a Δ-9,11 modification as a dissociative steroid. The Δ-9,11 analog showed potent inhibition of tumor necrosis factor-α-induced NF-κB signaling in cell reporter assays, and this transrepression activity was blocked by 17β-hydroxy-11β-[4-dimethylamino phenyl]-17α-[1-propynyl]estra-4,9-dien-3-one (RU-486), showing the requirement for the glucocorticoid receptor (GR). The Δ-9,11 analog induced the nuclear translocation of GR but showed the loss of transactivation as assayed by GR-luciferase constructs as well as mRNA profiles of treated cells. The Δ-9,11 analog was tested for efficacy and side effects in two mouse models of muscular dystrophy: mdx (dystrophin deficiency), and SJL (dysferlin deficiency). Daily oral delivery of the Δ-9,11 analog showed a reduction of muscle inflammation and improvements in multiple muscle function assays yet no reductions in body weight or spleen size, suggesting the loss of key side effects. Our data demonstrate that a Δ-9,11 analog dissociates the GR-mediated transcriptional activities from anti-inflammatory activities. Accordingly, Δ-9,11 analogs may hold promise as a source of safer therapeutic agents for chronic inflammatory disorders.

Nucleotide sequence and structure of the mouse carbonic anhydrase III gene

At least 14 distinct isozymes of carbonic anhydrase have been identified in mammals. These enzymes catalyze the hydration of carbon dioxide and are essential for regulation of cellular pH and carbon dioxide transport. Carbonic anhydrase III is highly expressed in certain tissues, including muscle and fat where it constitutes up to 25% of the soluble protein. We cloned a cDNA encoding mouse carbonic anhydrase III. This cDNA contains 1653 bp, consisting of 79 bp in the 5' UTR, a 780 bp open reading frame, and 794 bp of the 3' UTR, including two potential polyadenylation signals. Fluorescent in situ hybridization confirmed the existence of a single copy of the gene on chromosome 3. We then isolated the genomic DNA for mouse carbonic anhydrase III and analyzed its structure. The gene consists of seven exons and six introns which span 10.5 kb. The 5' flanking region of the genomic DNA is notable for a pyrimidine rich region consisting of two dinucleotide repeats containing 23 and 20 TC pairs separated by the same 15 bp spacer.