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Matrix Metalloproteinase Triple-Helical Peptide Inhibitors: Potential Cross-Reactivity with Caspase-11
Anna M Knapinska1, Melissa Hart1, Gary Drotleff1
1Department of Chemistry & Biochemistry, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA.
Abstract:
Triple-helical peptide inhibitors (THPIs) of matrix metalloproteinases (MMPs) have recently been demonstrated to be effective in a variety of animal models of disease, coincidental with knockout studies. However, passenger mutations have been described in MMP knockout mice that impact the activity of other proteins, including caspase-11. Thus, it is possible that the results observed with THPIs may be based on inhibition of caspase-11, not MMPs. The present study evaluated whether THPIs were cross-reactive with caspase-11. Two different THPIs were tested, one that is known to inhibit MMP-1 and MMP-8 (GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI) and one that is selective for MMP-2 and MMP-9 (α1(V)GlyΨ{PO2H-CH2}Val [mep14,32,Flp15,33] THPI). No inhibition of caspase-11 was observed with GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI, even at an inhibitor concentration of 5 μM, while 5 μM α1(V)GlyΨ{PO2H-CH2}Val [mep14,32,Flp15,33] THPI exhibited 40% inhibition of caspase-11. Further testing of GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI revealed nM inhibition of MMP-2, MMP-9, and MMP-13. Thus, the effectiveness of GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI observed in a sepsis animal model may not be due to caspase-11 inhibition, but may be due to broader MMP inhibition than previously thought.
Insights
Triple-helical peptide inhibitors (THPIs) targeting matrix metalloproteinases (MMPs) may not inhibit caspase-11. One THPI showed no caspase-11 inhibition, suggesting MMP inhibition is responsible for therapeutic effects.
Area of Science:
- Biochemistry
- Pharmacology
- Enzymology
Background:
- Triple-helical peptide inhibitors (THPIs) show efficacy in disease models, but concerns exist regarding off-target effects.
- Passenger mutations in knockout models can affect other proteins like caspase-11, complicating interpretation of THPI efficacy.
- This study investigates potential cross-reactivity of THPIs with caspase-11 to clarify their mechanism of action.
Purpose of the Study:
- To determine if THPIs exhibit cross-reactivity with caspase-11.
- To differentiate between MMP inhibition and caspase-11 inhibition as the mechanism for THPI efficacy.
- To characterize the inhibitory profile of specific THPIs against MMPs and caspase-11.
Main Methods:
- Two distinct THPIs were tested for their ability to inhibit caspase-11 activity in vitro.
- Enzyme inhibition assays were performed to quantify the potency of THPIs against specific matrix metalloproteinases (MMPs).
- Concentration-dependent inhibition curves were generated for relevant enzyme targets.
Main Results:
- GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI demonstrated no inhibition of caspase-11, even at high concentrations (5 μM).
- α1(V)GlyΨ{PO2H-CH2}Val [mep14,32,Flp15,33] THPI showed 40% inhibition of caspase-11 at 5 μM.
- GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI exhibited nanomolar inhibition against MMP-2, MMP-9, and MMP-13.
Conclusions:
- The therapeutic effects of GlyΨ{PO2H-CH2}Ile-His-Lys-Gln THPI in sepsis models are likely due to matrix metalloproteinase (MMP) inhibition, not caspase-11 inhibition.
- The tested THPIs display differential cross-reactivity with caspase-11, with one showing significant off-target activity.
- Further research is warranted to fully elucidate the therapeutic mechanisms of THPIs and ensure target specificity.
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