Remarkable new research platforms have been established during the late 1990's that will forever change the way we think about biological research, especially biomedical sciences. It is now believed that more than one "dysfunctional transcripts" contribute to some of the pathophysiology of various diseases. This new vision has been captured under the umbrella form of post genomics, a variety of related subcategories such as pharmacogenomics, Predictive medicine and chemogenomics.

Differential display of gene expression in normal and diseased cell/tissue has become an important component of gene mining. Human arthritis-affected tissue shows superinduction of inflammatory mediators and proteases involved in cell regulation, tissue modeling, and receptors/ligands involved in cell/matrix interactions. Human osteoarthritis is one of the musculoskeletal diseases which impacts various components of the musculoskeletal system. The present presentation concentrates on genomic analysis on human cartilage, which can be extended to other inflammatory diseases and cancer.

Various gene mining approaches (Gene Hunter Kit, DD-PCR using conserved sequences to MMPs, highthroughput sequencing of normalized and subtracted cDNA libraries, high density Affymetrix chips) using RNA obtained from normal and human osteoarthritis affected cartilage and micro-dissection using laser capture microscopy and proteomics have yielded various differentially expressed transcripts and targets. This includes the RT-PCR analysis of conserved domains of proteases (gene mining) identification (by bioinformatics) and characterization (by ex vivo organ cultures) of TNF alpha convertase (TACE) known to process proTNF alpha to soluble TNF alpha. This enzyme is a potential target for pharmacological intervention of TNF alpha known to be involved in the pathophysiology of various diseases.

Human OA-affected cartilage shows superinduction of two matrix proteins: fibronectin (FN) and osteopontin (OPN). Functional genomic analysis of FN and OPN in human cartilage organ cultures showed the role of two integrins in regulation of inflammatory mediators in human cartilage. Identification and preparation of agonist antibodies to one of them, alpha v beta 3, showed potent dominant negative anti-inflammatory activity in human cartilage and other cell types, which has potential therapeutic importance both in inflammation and cancer metastasis. Human OA-affected cartilage showed an absence of the type II IL-1 decoy receptor, which when analyzed for functional genomics, showed susceptibility of IL-1 to human cartilage as compared to other cell types such as epithelial cells in the lungs, which contribute to asthma. Reconstitution of this receptor by gene therapy approaches in human cells showed protection against the insults of IL-1.

Preliminary studies show that rodent and human chondrosarcoma release pro-inflammatory/angiogenic factors such as PGE₂ in vivo. In view of the recent role of COX-2 mediated PGE₂ in progression of colon and breast cancer, we will evaluate the effect of COX-2 specific inhibitors in a pharmacogenomic screen in vivo to dissect the role of PGE₂ in progression of chondrosarcomas. Experiments are in progress to extend these studies in lupus, asthma and multiple sclerosis.

In summary, the post-genomic era now provides a tool to analyze complex musculoskeletal and inflammatory diseases whose etiological agents remain unknown. Furthermore, high quality clinical material, access to well organized patient databases in an organizational structure where research and the clinic are completely homogenized will be an ideal platform for Post Genomics for medicine and drug validation and development.