Shahriar Mobashery

Tissue inhibitor of metalloproteinase (TIMP)-2 acts synergistically with synthetic matrix metalloproteinase (MMP) inhibitors but not with TIMP-4 to enhance the (Membrane type 1)-MMP-dependent activation of pro-MMP-2.

The membrane-type 1 matrix metalloproteinase (MT1-MMP) has been shown to be a key enzyme in tumor angiogenesis and metastasis. MT1-MMP hydrolyzes a variety of extracellular matrix components and is a physiological activator of pro-MMP-2, another MMP involved in malignancy. Pro-MMP-2 activation by MT1-MMP involves the formation of an MT1-MMP·tissue inhibitors of metalloproteinases 2 (TIMP-2)·pro-MMP-2 complex on the cell surface that promotes the hydrolysis of pro-MMP-2 by a neighboring TIMP-2-free MT1-MMP. The MT1-MMP·TIMP-2 complex also serves to reduce the intermolecular autocatalytic turnover of MT1-MMP, resulting in accumulation of active MT1-MMP (57 kDa) on the cell surface. Evidence shown here inTimp2-null cells demonstrates that pro-MMP-2 activation by MT1-MMP requires TIMP-2. In contrast, a C-terminally deleted TIMP-2 (Δ-TIMP-2), unable to form ternary complex, had no effect. However, Δ-TIMP-2 and certain synthetic MMP inhibitors, which inhibit MT1-MMP autocatalysis, can act synergistically with TIMP-2 in the promotion of pro-MMP-2 activation by MT1-MMP. In contrast, TIMP-4, an efficient MT1-MMP inhibitor, had no synergistic effect. These studies suggest that under certain conditions the pericellular activity of MT1-MMP in the presence of TIMP-2 can be modulated by synthetic and natural (TIMP-4) MMP inhibitors.

Roles of Matrix Metalloproteinases in Cutaneous Wound Healing

Wound healing is a complex process that consists of hemostasis and inflammation, angiogenesis, re-epithelialization, and tissue remodeling. Matrix metalloproteinases (MMPs) play important roles in wound healing, and their dysregulation leads to prolonged inflammation and delayed wound healing. There are 24 MMPs in humans, and each MMP exists in three forms, of which only the active MMPs play a role in the pathology or repair of wounds. The current methodology does not distinguish between the three forms of MMPs, making it challenging to investigate the roles of MMPs in pathology and wound repair. We used a novel MMP-inhibitor-tethered affinity resin that binds only the active form of MMPs, from which we identified and quantified active MMP-8 and active MMP-9 in a murine diabetic model with delayed wound healing. We showed that up-regulation of active MMP-9 plays a detrimental role whereas active MMP-8 is involved in repairing the wound in diabetic mice. These studies identified MMP-9 as a novel target for therapeutic intervention in the treatment of chronic wounds. A selective inhibitor of MMP-9 that leaves MMP-8 unaffected would provide the most effective therapy and represents a promising strategy for therapeutic intervention in the treatment of diabetic foot ulcers.

Chapter 10:Thiirane Class of Gelatinase Inhibitors as a Privileged Template that Crosses the Blood–Brain Barrier

The gelatinases (matrix metalloproteinase (MMP)-2 and MMP-9) play important roles in the pathophysiology of several diseases, including cancer metastases, neurological diseases, and chronic wounds. MMPs also mediate beneficial repair and recovery functions. Thus, the use of selective MMP inhibitors is required to avoid side effects. The prototype gelatinase inhibitor SB-3CT displays potency and selectivity towards the gelatinases. SB-3CT contains a thiirane ring that involves a reaction catalyzed by the gelatinases, which results in slow-binding and/or tight-binding inhibition. This unique mechanism of action is at the root of selectivity enjoyed by the thiirane class of inhibitors. We have synthesized and evaluated >500 thiirane derivatives. SB-3CT has shown efficacy in numerous animal models of disease, including cancer metastasis, stroke, traumatic brain injury, and diabetic wound healing. The members of the thiirane class cross the blood–brain barrier (BBB), achieve therapeutic concentrations in the brain, and do not accumulate in the brain. These desirable attributes of the thiiranes indicate that this class of gelatinase inhibitors holds great promise for intervention of neurological diseases and chronic wounds.