Timp3 Conditional Knockout mouse models

Timp3 is the mouse ortholog of human TIMP3 and encodes the only family member sequestered in extracellular matrix through sulfated glycosaminoglycan binding via its C-terminal domain, and the only one that potently inhibits ADAM17 (TACE), ADAM10, ADAM12, and the aggrecanases ADAMTS4 and ADAMTS5 in addition to classical MMPs. Because ADAM17 sheds TNF, TGF-alpha, IL-6 receptor, and Notch ligands, TIMP3 sets the tone of ectodomain shedding rather than only matrix turnover, and human C-terminal mutations cause Sorsby fundus dystrophy by promoting TIMP3 aggregation and dysregulated VEGF handling in Bruch membrane. Nulls are viable but develop air space enlargement, cardiac dilation, accelerated cartilage degradation, and enhanced TNF shedding, so germline deletion is tractable, while matrix-binding or Sorsby point knockins model dominant human disease and conditional alleles isolate chondrocyte, myeloid, or retinal pigment epithelium sources. Timp1, Timp2, and Timp4 do not substitute for ADAM17 inhibition, so target shedding, osteoarthritis, or neovascularization endpoints.

A floxed Timp3 allele paired with Cre gives spatial control that whole body knockouts cannot offer. People use it to separate developmental roles from adult homeostasis, to model somatic mutations, and to match disease that begins in one organ.