Fig 1: MT1-MMP directly cleaves insulin receptor to suppress insulin signaling.a Western blotting analyses on the expression of insulin receptor (IR) in the livers, white adipose tissues (WAT) and skeletal muscles from p15 wild-type (WT), Mmp14+/−, and Mmp14−/− mice (n = 4). b The protein expression of IR protein in primary wild-type and Mmp14−/− hepatocytes as well as Mmp14−/− hepatocytes reconstituted with either wild-type MT1-MMP (WT MT1) or catalytic inactive MT1-MMP (MT1 E280A) (n = 3). c HEK293T cells were transfected with either WT or E/A catalytic mutant MT1-MMP (MT1 E280A). The expression of full-length IR and sIR was detected in total cell lysate and conditioned media respectively by western blotting (n = 3). d The level of soluble insulin receptor (sIR) was measured in the plasma from p15 wild type (WT), Mmp14+/− and Mmp14−/− mice. (n = 8 for WT & Mmp14+/− mice; n = 6 for Mmp14−/− mice); one-way ANOVA (e) sIR amount was measured in the conditioned media from the wild-type (WT) and Mmp14−/− liver explants (n = 5); two-sided unpaired t test. f rIR was incubated with the recombinant catalytic domain of MT1-MMP (rMT1). The protein mixture was subjected to western blotting analyses using specific antibodies indicated (n = 3). g Co-immunoprecipitation experiments demonstrated the endogenous interaction between MT1-MMP and IR. IR and MT1-MMP immunoprecipitations (IP) were generated from liver lysates from wild-type mice and examined by western blotting analyses using indicated antibodies. IgG immunoprecipitation served as controls. Input loading showed the expression of the protein of interest in the cell lysate without the addition of an antibody (n = 3). Data are reported as average ± s.e.m. Source data are provided as a Source Data file.
Fig 2: Ectopic expression of MT1-MMP in the hippocampus induces cognitive deficit in 2-month-old young mice.a Percentage preference for the displaced object in the object location task from mice receiving either AAV-control, AAV-WT MT1-MMP, or AAV-MT1 EA. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 8 mice per group). b, c Percentage of total time spent in the target quadrant (b) and distance traveled to the target hole (c) in the Barnes maze test. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 5 mice per group). d Percentage of freezing time during a contextual fear conditioning test. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 6 mice per group). e, f Changes in fEPSP in the hippocampal CA1 for LTP analysis (e) and the average of fEPSP (f). One-way ANOVA followed by Tukey’s multiple comparisons test (n = 6 mice per group). g–i Young and aged mice treated with C52 (10 mg/kg/day) for two weeks after AAV injection and tested for spatial memory using object location task (g) and Barnes maze test (h, i). One-way ANOVA followed by Tukey’s multiple comparisons test (n = 6 mice per group). Data are expressed as mean ± SEM, and each data point represents individual mouse.
Fig 3: MT1-MMP regulates cognitive aging by suppressing Ocn/Gpr158 signaling axis.a The preference for the displaced object in the object location task by 2-month-old (young), 18-month-old (aged) WT and Mmp14+/− aged mice injected with either shControl or shGpr158. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 7 young + shControl, n = 6 aged + shControl, n = 6 aged + shGpr158, n = 7 Mmp14+/− aged + shControl, n = 6 Mmp14+/− aged + shGpr158). b, c Percentage of total time spent in the target quadrant (b) and distance traveled to the target hole (c) in Barnes maze test. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 6 mice per group). d, e LTP analysis in the CA1 hippocampus region by measuring the fEPSP (d) and the average of fEPSP slope (e). One-way ANOVA followed by Fisher’s LSD post hoc test (n = 5 mice per group). Data are expressed as mean ± SEM, and each data point represents individual mouse.
Fig 4: Pharmacological inhibition of MT1-MMP improves memory function and metabolism in 18-month-old aged mice.a, b Cognitive function assessment using the Y-maze task (a) and contextual memory assessment (b) by examining the percentage of time freezing. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 8 young + vehicle, n = 8 young + Ro 28-2653, n = 11 aged + vehicle, n = 11 aged + Ro 28-2653 mice). c Body weight changes at the end of the experiment. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 8 young + vehicle, n = 9 young + Ro 28-2653, n = 16 aged + vehicle, n = 18 aged + Ro 28-2653 mice). d, e The area under curve (AUC) was calculated based on the glucose level of each time point during GTT (d) and ITT (e). One-way ANOVA followed by Fisher’s LSD post hoc test (n = 8 young + vehicle, n = 8 young + Ro 28-2653, n = 16 aged + vehicle, n = 18 aged + Ro 28-2653 mice). f–h Liver toxicity assessment by examining the serum for AST (f), ALT (g), and hepatic TG (h) levels. One-way ANOVA followed by Tukey’s multiple comparisons test (n = 8 young + vehicle, n = 9 young + Ro 28-2653, n = 16 aged + vehicle, n = 18 aged + Ro 28-2653 mice). For 4 weeks, either IgG or 3A2 was administered intrahippocampally. i, j Following this treatment, cognitive function was assessed using the Y-maze test (i) and the contextual fear conditioning test (j). One-way ANOVA followed by Tukey’s multiple comparisons test (n = 7–8 mice per group). Data are expressed as mean ± SEM, and each data point represents individual mouse.
Fig 5: Hemizygous depletion of MT1-MMP promotes insulin sensitivity in aged mice.In all, 18-months-old WT and Mmp14+/− mice on a chow diet were compared: a body weight and composition (n = 6), b fasting plasma glucose (n = 6), c fasting plasma insulin (n = 6), d glucose-tolerance test (n = 6), e insulin-tolerance test (n = 6), f WT and Mmp14+/- mice fed chow diet at the age of 18 months were challenged with insulin. The expression of phosphorylated Akt (pAkt) in relative to the level of total Akt (tAkt) in the livers, white adipose tissues (WAT) and muscles was examined by western blotting and quantified. (n = 3) Representative western blots were shown in Supplementary Fig. S4D. Data are reported as average ± s.e.m.; two-sided unpaired t test (a–c) one-way ANOVA (f) or two-way ANOVA (d, e). Source data are provided as a Source Data file.
Supplier Page from Enzo Life Sciences, Inc. for MMP-14 (catalytic domain) (human), (recombinant)