Glomerular diseases, also called glomerulonephritides (GNs), refer to all those conditions that affect glomeruli, the filtering units of the kidney. If left untreated or not managed effectively, progressive GNs may result in a range of complications, including chronic kidney disease and end-stage renal disease. Some pathophysiological aspects of GNs are treatable, with several novel mode of action (MoA) drugs reaching the market in recent years, but a strong unmet medical need persists and identification of novel potential GN therapeutic targets is still an active field of research in nephrology. In the present thesis work, I present evidence of the relevance of a newly identified hyaluronic acid degrading protein named Cell migration-inducing and hyaluronan-binding protein (CEMIP). CEMIP is specifically upregulated upon activation of the collagen receptor Discoidin Domain Receptor 1 (DDR1), an accepted molecular target shown to have a role in GN initiation and progression. Analysis of patient biopsies and CEMIP deletion experiment in a mouse model of GN suggested that the DDR1/CEMIP axis could play a role in renal pathologies characterized by a crescentic phase. This role may be mediated by CEMIP hyaluronidase activity, which generates low molecular weight hyaluronic acid (LMW-HA) fragments, known to be signaling molecules in inflammation. To date, very little scientific knowledge has been reported on the activity, mechanism and mode of action of these CEMIP-generated fragments. Our current grasp of CEMIP biology is dominated by the vast body of literature that has investigated CEMIP expression and/or deletion in cancer models such as in the context of tumor proliferation and invasion. After preliminary results assessed the role of CEMIP in GN, in the present work I sought to study its molecular MoA. Mutagenesis experiments confirmed the position of the key amino acid residues used by CEMIP to bind selectively to hyaluronic acid and identified, for the first time, the ones belonging to CEMIP postulated catalytic site. Additional experiments shed light on the role and importance of other domains of CEMIP as well as on the catalytic function of intracellular and secreted CEMIP. This molecular knowledge was used to design, synthesize and evaluate, using newly developed cellular assays, small molecule inhibitors on CEMIP hyaluronidase activity. A parallel effort was conducted to solve CEMIP structure by cryo-EM and one of its domains (the GG domain) by X-ray crystallography. All those efforts will hopefully result in the creation of CEMIP inhibitors active in vivo. The availability of such tool compounds will be then tested in preclinical model of GNs and cancer.