Hockla, A. | bioRxiv Science

bioRxiv2024

Improving Circulation Half-Life of Therapeutic Candidate N-TIMP2 by Unfolded Peptide Extension

Matrix Metalloproteinases (MMPs) are drivers of many diseases including cancer and are established targets for drug development. Tissue inhibitors of metalloproteinases (TIMPs) are human proteins that inhibit MMPs and are being pursued for the development of anti-MMP therapeutics. TIMPs possess many attractive properties of a drug candidate, such as complete MMP inhibition, low toxicity and immunogenicity, high tissue permeability and others. A major challenge with TIMPs, however, is their formulation and delivery, as these proteins are quickly cleared from the bloodstream due to their small size. In this study, we explore a new method for plasma half-life extension for the N-terminal domain of TIMP2 (N-TIMP2) through appending it with a long intrinsically unfolded tail containing a random combination of Pro, Ala, and Thr (PATylation). We design, produce and explore two PATylated N-TIMP2 constructs with a tail length of 100- and 200-amino acids (N-TIMP2-PAT100 and N-TIMP2-PAT200, respectively). We demonstrate that both PATylated N-TIMP2 constructs possess apparent higher molecular weights compared to the wild-type protein and retain high inhibitory activity against MMP-9. Furthermore, when injected into mice, N-TIMP2-PAT200 exhibited a significant increase in plasma half-life compared to the non-PATylated variant, enhancing the therapeutic potential of the protein. Thus, we establish that PATylation could be successfully applied to TIMP-based therapeutics and offers distinct advantages as an approach for half-life extension, such as fully genetic encoding of the gene construct, mono-dispersion, and biodegradability. Furthermore, PATylation could be easily applied to N-TIMP2 variants engineered to possess high affinity and selectivity toward individual MMP family members, thus creating attractive candidates for drug development against MMP-related diseases.

biochemistry↗

bioRxiv2022

A broad matrix metalloproteinase inhibitor with designed loop extension exhibits ultrahigh specificity for MMP-14

Matrix metalloproteinases (MMPs) are key drivers of various diseases, including cancer. While several antibodies against MMPs are in development, our goal is to construct therapeutic anti-MMP inhibitors based on a natural broad MMP inhibitor, tissue inhibitor of metalloproteinases-2 (N-TIMP2). To confer high binding specificity toward one MMP type, we extend one of the N-TIMP2 loops, allowing it to interact with the non-conserved MMP surface. Multiple computational designs of the loop were used to design a focused library for yeast surface display, which was sorted for high binding to the target MMP-14 and low binding to off-target MMP-3. Deep sequencing of the two selected populations followed by comparative data analysis was used to identify the most promising variants, which were expressed, purified, and tested for inhibition of MMP-14 and off-target MMPs. Our best N-TIMP2 variant exhibited 29 pM binding affinity to MMP-14 and 2.4 {micro}M affinity to MMP-3, 7500-fold more specific than WT N-TIMP2. Furthermore, the variant inhibited cell invasion with increased potency relative to WT N-TIMP2 in two breast cancer cell lines. We obtained the engineered variant high-accuracy model by including NGS data as input to AlphaFold multiple sequence alignment (MSA). Modeling results together with experimental mutagenesis demonstrate that the loop packs tightly against non-conserved residues on MMP-14 and clashes with MMP-3. This study demonstrates that introduction of loop extensions into inhibitors to stretch to the non-conserved surface of the target proteins is an attractive strategy for conferring high binding specificity in design of MMP inhibitors and other therapeutic proteins.

biochemistry↗