Chuanzheng Song

Identification of a family of cAMP response element-binding protein coactivators by genome-scale functional analysis in mammalian cells

This report describes an unbiased method for systematically determining gene function in mammalian cells. A total of 20,704 predicted human full-length cDNAs were tested for induction of the IL-8 promoter. A number of genes, including those for cytokines, receptors, adapters, kinases, and transcription factors, were identified that induced the IL-8 promoter through known regulatory sites. Proteins that acted through a cooperative interaction between an AP-1 and an unrecognized cAMP response element (CRE)-like site were also identified. A protein, termed transducer of regulated cAMP response element-binding protein (CREB) (TORC1), was identified that activated expression through the variant CRE and consensus CRE sites. TORC1 potently induced known CREB1 target genes, bound CREB1, and activated expression through a potent transcription activation domain. A functional Drosophila TORC gene was also identified. Thus, TORCs represent a family of highly conserved CREB coactivators that may control the potency and specificity of CRE-mediated responses.

Role of the cysteine protease cathepsin S in neuropathic hyperalgesia

Abstract Using a gene expression analysis approach we found that the mRNA encoding the lysosomal cysteine protease cathepsin S (CatS) was up‐regulated in rat dorsal root ganglia (DRG) following peripheral nerve injury. CatS protein was expressed in infiltrating macrophages in DRG and near the site of injury. At both sites CatS expression progressively increased from day 3 to day 14 after injury. In naïve rats, intraplantar injection of activated rat recombinant (rr) CatS (0.3, 1 μg/rat) induced a mechanical hyperalgesia that developed within half‐an‐hour, diminished by 3 h and was absent after 24 h. Activated rrCathepsin B (CatB) and non‐activated rrCatS injected intraplantarly at the same or higher doses than activated rrCatS had no effect on rat nociceptive thresholds. In nerve‐injured rats, mechanical hyperalgesia, but not allodynia, was significantly reversed for up to 3 h by systemic administration of a non‐brain penetrant, irreversible CatS inhibitor (LHVS, 3–30 mg/kg s.c.). Depletion of peripheral macrophages by intravenous injection of liposome encapsulate clodronate (1 ml, 5 mg/ml) partially reduced established mechanical hyperalgesia but not allodynia, and abolished the anti‐hyperalgesic effect of LHVS. Our results demonstrate a pro‐nociceptive effect of CatS and indicate that endogenous CatS released by peripheral macrophages contributes to the maintenance of neuropathic hyperalgesia following nerve injury.