Non-specific antiviral activity of antisense molecules targeted to the E1 region of human papillomavirus.

Antisense phosphorothioate oligonucleotides (ODN1 0x5 OMe) directed against the E1 start region of human papillomavirus 11 (HPV11) can inhibit papillomavirus induced growth of implanted human foreskin in a mouse xenograft model. Administration of a mismatch control oligonucleotide (ODN9 0x5 OMe), in which guanine was replaced with adenine in the same model, had no effect on papilloma induced growth. However, the apparent antiviral activity of ODN1 0x5 OMe was also shown in a lethal mouse cytomegalovirus (CMV) model, in which the oligonucleotides are not expected to have antisense activity. To understand the mechanisms of action of these oligonucleotides, a mismatch oligonucleotide (ODN61 0x5 OMe) was prepared which retained the CpG motifs of ODN1 0x5 OMe. This was tested in the mouse xenograft model and shown to have moderate inhibitory activity. As a definitive experiment, a comparison was made between the efficacy of the active oligonucleotide ODN1 0x5 OMe against two papilloma viruses HPV11 and HPV40. Both these viruses cause benign genital warts, but differ by four bases in their E1 sequence that was the target for ODN1 0x5 OMe. Papillomavirus induced growth in the mouse xenograft model was inhibited by ODN1 0x5 OMe in both cases, suggesting that oligonucleotide molecules have a non-specific antiviral activity that is not directly related to their antisense sequence.

Ro 32-3555, an orally active collagenase selective inhibitor, prevents structural damage in the STR/ORT mouse model of osteoarthritis.

OBJECTIVE: To determine the efficacy of a selective inhibitor of collagenases in an animal model of osteoarthritis (OA). METHODS: Ro 32-3555, an orally active collagenase selective inhibitor, was administered to STR/ORT mice. Microfocal x-ray-generated images of the hind limbs were visually scored for joint space narrowing, osteophyte formation, and calcification of tendons. Histologic sections of the knees were scored for cartilage changes including loss of surface matrix, fibrillation, and eburnation. RESULTS: Significant inhibition of joint space narrowing and osteophyte formation was achieved in groups of animals treated with 10-50 mg/kg(-1) of Ro 32-3555. These effects were confirmed histologically in the same groups of animals: histologic analysis revealed that Ro 32-3555 protected cartilage from degradative changes. CONCLUSION: Ro 32-3555, a collagenase selective inhibitor, inhibits both the cartilage and bone changes in this mouse model of OA, and thus shows great potential as a treatment of OA in humans.

Ro 32-3555, an orally active collagenase inhibitor, prevents cartilage breakdown in vitro and in vivo.

1. Ro 32-3555 (3(R)-(cyclopentylmethyl)-2(R)-[(3,4,4-trimethyl-2,5-dioxo-1- imidazolidinyl)methyl]-4-oxo-4-piperidinobutyrohydroxamic acid) is a potent, competitive inhibitor of human collagenases 1, 2 and 3 (Ki values of 3.0, 4.4 and 3.4 nM, respectively). The compound is a selective inhibitor of collagenases over the related human matrix metalloproteinases stromelysin 1, and gelatinases A and B (Ki values of 527, 154 and 59 nM, respectively). 2. Ro 32-3555 inhibited interleukin-1 alpha (IL-1 alpha)-induced cartilage collagen degradation in vitro in bovine nasal cartilage explants (IC50 = 60 nM). 3. Ro 32-3555 was well absorbed in rats when administered orally. Systemic exposure was dose related, with an oral bioavailability of 26% at a dose of 25 mg kg-1. 4. Ro 32-3555 prevented granuloma-induced degradation of bovine nasal cartilage cylinders implanted subcutaneously into rats (ED50 = 10 mg kg-1, twice daily, p.o.). 5. Ro 32-3555 dosed once daily for 14 days at 50 mg kg-1, p.o., inhibited degradation of articular cartilage in a rat monoarthritis model induced by an intra-articular injection of Propionibacterium acnes. 6. Ro 32-3555 is a potential therapy for the treatment of the chronic destruction of articulating cartilage in both rheumatoid and osteoarthritis.

A novel in vivo model for the study of cartilage degradation.

Methods of quantifying cartilage destruction are described using a sponge/cartilage implant model in the rat. A cylinder of bovine nasal cartilage was positioned in the center of a sponge which had been pretreated with an irritant. The sponge/cartilages were then implanted subcutaneously into the backs of rats for periods of up to 16 days. The implanted sponges were rapidly surrounded by granulation tissue, maximal on day 2, and infiltrated by inflammatory cells which reached peak levels on day 9. Analysis of the cartilage shows an initial increase in wet weight and rapid loss of glycosaminoglycans. These changes were later followed by loss of cartilage wet weight and significant loss of hydroxyproline content. In a separate study, the effects of Mycobacterium tuberculosis (Mtb), kaolin, and zymosan were compared (1 mg/sponge) and the results showed that only Mtb induced pronounced inflammation and degradation of cartilage. The cartilage degradation directly correlated with the granulation tissue weight, but not with cellular infiltration. We believe that this simple, reproducible in vivo model could be used to elucidate the mechanisms involved in the destructive process and evaluate the efficacy of inhibitors of cartilage degradation.