Multilevel proteomics reveals host perturbations by SARS-CoV-2 and SARS-CoV.

The emergence and global spread of SARS-CoV-2 has resulted in the urgent need for an in-depth understanding of molecular functions of viral proteins and their interactions with the host proteome. Several individual omics studies have extended our knowledge of COVID-19 pathophysiology1-10. Integration of such datasets to obtain a holistic view of virus-host interactions and to define the pathogenic properties of SARS-CoV-2 is limited by the heterogeneity of the experimental systems. Here we report a concurrent multi-omics study of SARS-CoV-2 and SARS-CoV. Using state-of-the-art proteomics, we profiled the interactomes of both viruses, as well as their influence on the transcriptome, proteome, ubiquitinome and phosphoproteome of a lung-derived human cell line. Projecting these data onto the global network of cellular interactions revealed crosstalk between the perturbations taking place upon infection with SARS-CoV-2 and SARS-CoV at different levels and enabled identification of distinct and common molecular mechanisms of these closely related coronaviruses. The TGF-ß pathway, known for its involvement in tissue fibrosis, was specifically dysregulated by SARS-CoV-2 ORF8 and autophagy was specifically dysregulated by SARS-CoV-2 ORF3. The extensive dataset (available at https://covinet.innatelab.org ) highlights many hotspots that could be targeted by existing drugs and may be used to guide rational design of virus- and host-directed therapies, which we exemplify by identifying inhibitors of kinases and matrix metalloproteases with potent antiviral effects against SARS-CoV-2.

Matrix metalloproteinases: regulators of the tumor microenvironment.

Extracellular proteolysis mediates tissue homeostasis. In cancer, altered proteolysis leads to unregulated tumor growth, tissue remodeling, inflammation, tissue invasion, and metastasis. The matrix metalloproteinases (MMPs) represent the most prominent family of proteinases associated with tumorigenesis. Recent technological developments have markedly advanced our understanding of MMPs as modulators of the tumor microenvironment. In addition to their role in extracellular matrix turnover and cancer cell migration, MMPs regulate signaling pathways that control cell growth, inflammation, or angiogenesis and may even work in a nonproteolytic manner. These aspects of MMP function are reorienting our approaches to cancer therapy.

Matrix Metalloproteinases: From Molecular Mechanisms to Physiology, Pathophysiology, and Pharmacology.

The first matrix metalloproteinase (MMP) was discovered in 1962 from the tail of a tadpole by its ability to degrade collagen. As their name suggests, matrix metalloproteinases are proteases capable of remodeling the extracellular matrix. More recently, MMPs have been demonstrated to play numerous additional biologic roles in cell signaling, immune regulation, and transcriptional control, all of which are unrelated to the degradation of the extracellular matrix. In this review, we will present milestones and major discoveries of MMP research, including various clinical trials for the use of MMP inhibitors. We will discuss the reasons behind the failures of most MMP inhibitors for the treatment of cancer and inflammatory diseases. There are still misconceptions about the pathophysiological roles of MMPs and the best strategies to inhibit their detrimental functions. This review aims to discuss MMPs in preclinical models and human pathologies. We will discuss new biochemical tools to track their proteolytic activity in vivo and ex vivo, in addition to future pharmacological alternatives to inhibit their detrimental functions in diseases. SIGNIFICANCE STATEMENT: Matrix metalloproteinases (MMPs) have been implicated in most inflammatory, autoimmune, cancers, and pathogen-mediated diseases. Initially overlooked, MMP contributions can be both beneficial and detrimental in disease progression and resolution. Thousands of MMP substrates have been suggested, and a few hundred have been validated. After more than 60 years of MMP research, there remain intriguing enigmas to solve regarding their biological functions in diseases.

Data-Independent Acquisition Proteomics and N-Terminomics Methods Reveal Alterations in Mitochondrial Function and Metabolism in Ischemic-Reperfused Hearts.

Myocardial ischemia-reperfusion (IR) (stunning) injury triggers changes in the proteome and degradome of the heart. Here, we utilize quantitative proteomics and comprehensive degradomics to investigate the molecular mechanisms of IR injury in isolated rat hearts. The control group underwent aerobic perfusion, while the IR injury group underwent 20 min of ischemia and 30 min of reperfusion to induce a stunning injury. As MMP-2 activation has been shown to contribute to myocardial injury, hearts also underwent IR injury with ARP-100, an MMP-2-preferring inhibitor, to dissect the contribution of MMP-2 to IR injury. Using data-independent acquisition (DIA) and mass spectroscopy, we quantified 4468 proteins in ventricular extracts, whereby 447 proteins showed significant alterations among the three groups. We then used subtiligase-mediated N-terminomic labeling to identify more than a hundred specific cleavage sites. Among these protease substrates, 15 were identified following IR injury. We identified alterations in numerous proteins involved in mitochondrial function and metabolism following IR injury. Our findings provide valuable insights into the biochemical mechanisms of myocardial IR injury, suggesting alterations in reactive oxygen/nitrogen species handling and generation, fatty acid metabolism, mitochondrial function and metabolism, and cardiomyocyte contraction.

Effect of Incomplete Cryoablation and Matrix Metalloproteinase Inhibition on Intratumoral CD8+ T-Cell Infiltration in Murine Hepatocellular Carcinoma.

Background Image-guided tumor ablation is the first-line therapy for early-stage hepatocellular carcinoma (HCC), with ongoing investigations into its combination with immunotherapies. Matrix metalloproteinase (MMP) inhibition demonstrates immunomodulatory potential and reduces HCC tumor growth when combined with ablative treatment. Purpose To evaluate the effect of incomplete cryoablation with or without MMP inhibition on the local immune response in residual tumors in a murine HCC model. Materials and Methods Sixty 8- to 10-week-old female BALB/c mice underwent HCC induction with use of orthotopic implantation of syngeneic Tib-75 cells. After 7 days, mice with a single lesion were randomized into treatment groups: (a) no treatment, (b) MMP inhibitor, (c) incomplete cryoablation, and (d) incomplete cryoablation and MMP inhibitor. Macrophage and T-cell subsets were assessed in tissue samples with use of immunohistochemistry and immunofluorescence (cell averages calculated using five 1-µm2 fields of view [FOVs]). C-X-C motif chemokine receptor type 3 (CXCR3)- and interferon γ (IFNγ)-positive T cells were assessed using flow cytometry. Groups were compared using unpaired Student t tests, one-way analysis of variance with Tukey correction, and the Kruskal-Wallis test with Dunn correction. Results Mice treated with incomplete cryoablation (n = 6) showed greater infiltration of CD206+ tumor-associated macrophages (mean, 1.52 cells per FOV vs 0.64 cells per FOV; P = .03) and MMP9-expressing cells (mean, 0.89 cells per FOV vs 0.11 cells per FOV; P = .03) compared with untreated controls (n = 6). Incomplete cryoablation with MMP inhibition (n = 6) versus without (n = 6) led to greater CD8+ T-cell (mean, 15.8% vs 8.29%; P = .04), CXCR3+CD8+ T-cell (mean, 11.64% vs 8.47%; P = .004), and IFNγ+CD8+ T-cell infiltration (mean, 11.58% vs 5.18%; P = .02). Conclusion In a mouse model of HCC, incomplete cryoablation and systemic MMP inhibition showed increased cytotoxic CD8+ T-cell infiltration into the residual tumor compared with either treatment alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Gemmete in this issue.

Discovery of novel indole derivatives as potent and selective inhibitors of proMMP-9 activation.

Matrix metalloproteinase-9 (MMP-9) is a secreted zinc-dependent endopeptidase that degrades the extracellular matrix and basement membrane of neurons, and then contributes to synaptic plasticity by remodeling the extracellular matrix. Inhibition of MMP-9 activity has therapeutic potential for neurodegenerative diseases such as fragile X syndrome. This paper reports the molecular design, synthesis, and in vitro studies of novel indole derivatives as inhibitors of proMMP-9 activation. High-throughput screening (HTS) of our internal compound library and subsequent merging of hit compounds 1 and 2 provided compound 4 as a bona-fide lead. X-ray structure-based design and subsequent lead optimization led to the discovery of compound 33, a highly potent and selective inhibitor of proMMP-9 activation.

Chemosensitization of non-small cell lung cancer to sorafenib via non-hydroxamate s-triazinedione-based MMP-9/10 inhibitors.

Non-small cell lung cancer (NSCLC) continues to be a leading cause of cancer death. Its fatality is associated with angiogenesis and metastasis. While VEGFR inhibitors are expected to be the central pillar for halting lung cancer, several clinical reports declared their subpar activities as monotherapy. These results directed combination studies of VEGFR inhibitors, especially sorafenib (Nexavar®), with various chemotherapeutic agents. Matrix metalloproteinase (MMP) inhibitors are seldom utilized in such combinations despite the expected complementary therapeutic outcome. This could be attributed to the clinical unsuitability of MMP inhibitors from the hydroxamate family. Herein, we report new non-hydroxamate s-triazinedione-based inhibitors of MMP-9 (6b; IC50 = 0.112 µM), and MMP-10 (6e; IC50 = 0.076 µM) surpassing the hydroxamate inhibitor NNGH for chemosensitization of NSCLC to sorafenib. MMPs inhibition profiling of the hits revealed MMP-9 over -2 and MMP-10 over -13 selectivity. 6b and 6e were potent (IC50 = 0.139 and 0.136 µM), safe (SI up to 6.77) and superior to sorafenib (IC50 = 0.506 µM, SI = 6.27) against A549 cells. When combined with sorafenib, the studied MMP inhibitors enhanced its cytotoxic efficacy up to 26 folds as confirmed by CI and DRI values for 6b (CI = 0.160 and DRI = 22.175) and 6e (CI = 0.096 and DRI = 29.060). 6b and 6e exerted anti-invasive activities in A549 cells as single agents (22.66 and 39.67 %) and in sorafenib combinations (29.96 and 91.83 %) compared to untreated control. Both compounds downregulated VEGF in A549 cells by approximately 70 % when combined with sorafenib, highlighting enhanced anti-angiogenic activities. Collectively, combinations of 6b and 6e with sorafenib demonstrated synergistic NSCLC cytotoxicity with pronounced anti-invasive and anti-angiogenic activities introducing a promising start point for preclinical studies.

Computational design of matrix metalloprotenaise-9 (MMP-9) resistant to auto-cleavage.

Matrix metalloproteinase-9 (MMP-9) is an endopeptidase that remodels the extracellular matrix. MMP-9 has been implicated in several diseases including neurodegeneration, arthritis, cardiovascular diseases, fibrosis and several types of cancer, resulting in a high demand for MMP-9 inhibitors for therapeutic purposes. For such drug design efforts, large amounts of MMP-9 are required. Yet, the catalytic domain of MMP-9 (MMP-9Cat) is an intrinsically unstable enzyme that tends to auto-cleave within minutes, making it difficult to use in drug design experiments and other biophysical studies. We set our goal to design MMP-9Cat variant that is active but stable to auto-cleavage. For this purpose, we first identified potential auto-cleavage sites on MMP-9Cat using mass spectroscopy and then eliminated the auto-cleavage site by predicting mutations that minimize auto-cleavage potential without reducing enzyme stability. Four computationally designed MMP-9Cat variants were experimentally constructed and evaluated for auto-cleavage and enzyme activity. Our best variant, Des2, with 2 mutations, was as active as the wild-type enzyme but did not exhibit auto-cleavage after 7 days of incubation at 37°C. This MMP-9Cat variant, with an identical with MMP-9Cat WT active site, is an ideal candidate for drug design experiments targeting MMP-9 and enzyme crystallization experiments. The developed strategy for MMP-9CAT stabilization could be applied to redesign other proteases to improve their stability for various biotechnological applications.

Non-small cell lung cancer sensitisation to platinum chemotherapy via new thiazole-triazole hybrids acting as dual T-type CCB/MMP-9 inhibitors.

Cisplatin remains the unchallenged standard therapy for NSCLC. However, it is not completely curative due to drug resistance and oxidative stress-induced toxicity. Drug resistance is linked to overexpression of matrix metalloproteinases (MMPs) and aberrant calcium signalling. We report synthesis of novel thiazole-triazole hybrids as MMP-9 inhibitors with T-type calcium channel blocking and antioxidant effects to sensitise NSCLC to cisplatin and ameliorate its toxicity. MTT and whole cell patch clamp assays revealed that 6d has a balanced profile of cytotoxicity (IC50 = 21 ± 1 nM, SI = 12.14) and T-type calcium channel blocking activity (⁓60% at 10 µM). It exhibited moderate ROS scavenging activity and nanomolar MMP-9 inhibition (IC50 = 90 ± 7 nM) surpassing NNGH with MMP-9 over -2 and MMP-10 over -13 selectivity. Docking and MDs simulated its receptor binding mode. Combination studies confirmed that 6d synergized with cisplatin (CI = 0.69 ± 0.05) lowering its IC50 by 6.89 folds. Overall, the study introduces potential lead adjuvants for NSCLC platinum-based therapy.

Biphenylsulfonamides as effective MMP-2 inhibitors with promising antileukemic efficacy: Synthesis, in vitro biological evaluation, molecular docking, and MD simulation analysis.

Overexpression of matrix metalloproteinase-2 (MMP-2) possesses a correlation with leukemia especially chronic myeloid leukemia (CML). However, no such MMP-2 inhibitor has come out in the market to date for treating leukemia. In this study, synthesis, biological evaluation, and molecular modeling studies of a set of biphenylsulfonamide derivatives as promising MMP-2 inhibitors were performed, focusing on their potential applications as antileukemic therapeutics. Compounds DH-18 and DH-19 exerted the most effective MMP-2 inhibition (IC50 of 139.45 nM and 115.16 nM, respectively) with potent antileukemic efficacy against the CML cell line K562 (IC50 of 0.338 µM and 0.398 µM, respectively). The lead molecules DH-18 and DH-19 reduced the MMP-2 expression by 21.3% and 17.8%, respectively with effective apoptotic induction (45.4% and 39.8%, respectively) in the K562 cell line. Moreover, both these compounds significantly arrested different phases of the cell cycle. Again, both these molecules depicted promising antiangiogenic efficacy in the ACHN cell line. Nevertheless, the molecular docking and molecular dynamics (MD) simulation studies revealed that DH-18 formed strong bidentate chelation with the catalytic Zn2+ ion through the hydroxamate zinc binding group (ZBG). Apart from that, the MD simulation study also disclosed stable binding interactions of DH-18 and MMP-2 along with crucial interactions with active site amino acid residues namely His120, Glu121, His124, His130, Pro140, and Tyr142. In a nutshell, this study highlighted the importance of biphenylsulfonamide-based novel and promising MMP-2 inhibitors to open up a new avenue for potential therapy against CML.

Pharmacological Inhibition of MMP-12 Exerts Protective Effects on Angiotensin II-Induced Abdominal Aortic Aneurysms in Apolipoprotein E-Deficient Mice.

Human abdominal aortic aneurysms (AAAs) are characterized by increased activity of matrix metalloproteinases (MMP), including MMP-12, alongside macrophage accumulation and elastin degradation, in conjunction with superimposed atherosclerosis. Previous genetic ablation studies have proposed contradictory roles for MMP-12 in AAA development. In this study, we aimed to elucidate if pharmacological inhibition of MMP-12 activity with a phosphinic peptide inhibitor protects from AAA formation and progression in angiotensin (Ang) II-infused Apoe-/- mice. Complimentary studies were conducted in a human ex vivo model of early aneurysm development. Administration of an MMP-12 inhibitor (RXP470.1) protected hypercholesterolemia Apoe-/- mice from Ang II-induced AAA formation and rupture-related death, associated with diminished medial thinning and elastin fragmentation alongside increased collagen deposition. Proteomic analyses confirmed a beneficial effect of MMP-12 inhibition on extracellular matrix remodeling proteins combined with inflammatory pathways. Furthermore, RXP470.1 treatment of mice with pre-existing AAAs exerted beneficial effects as observed through suppressed aortic dilation and rupture, medial thinning, and elastin destruction. Our findings indicate that pharmacological inhibition of MMP-12 activity retards AAA progression and improves survival in mice providing proof-of-concept evidence to motivate translational work for MMP-12 inhibitor therapy in humans.

Skin Malignant Melanoma and Matrix Metalloproteinases: Promising Links to Efficient Therapies.

Skin malignant melanoma (MM) is one of the most frequent and aggressive neoplasia worldwide. Its associated high mortality rates are mostly due to its metastases, while diagnosis and treatment of MM in its early stages is of favorable prognostic. Even skin superficial MMs at incipient local stages can already present with lymph node invasion and distant metastases. Therefore, knowledge of the controllable risk factors and pathogenic mechanisms of MM development, spreading, and metastatic pattern, as well as early diagnosis, are essential to decrease the high mortality rates associated with cutaneous malignant melanoma. Genetic factors are incriminated, although lifetime-acquired genetic mutations appear to be even more frequently involved in the development of MM. Skin melanocytes divide only twice per year and have time to accumulate genetic mutations as a consequence of environmental aggressive factors, such as UV exposure. In the search for more promising therapies, matrix metalloproteinases have become of significant interest, such as MMP-1, MMP-2, MMP-9, and MMP-13, which have been linked to more aggressive forms of cancer and earlier metastases. Therefore, the development of specific synthetic inhibitors of MMP secretion or activity could represent a more promising and effective approach to the personalized treatment of MM patients.

A Novel Strategy for the Treatment of Aneurysms: Inhibition of MMP-9 Activity through the Delivery of TIMP-1 Encoding Synthetic mRNA into Arteries.

Aneurysms pose life-threatening risks due to the dilatation of the arteries and carry a high risk of rupture. Despite continuous research efforts, there are still no satisfactory or clinically effective pharmaceutical treatments for this condition. Accelerated inflammatory processes during aneurysm development lead to increased levels of matrix metalloproteinases (MMPs) and destabilization of the vessel wall through the degradation of the structural components of the extracellular matrix (ECM), mainly collagen and elastin. Tissue inhibitors of metalloproteinases (TIMPs) directly regulate MMP activity and consequently inhibit ECM proteolysis. In this work, the synthesis of TIMP-1 protein was increased by the exogenous delivery of synthetic TIMP-1 encoding mRNA into aortic vessel tissue in an attempt to inhibit MMP-9. In vitro, TIMP-1 mRNA transfection resulted in significantly increased TIMP-1 protein expression in various cells. The functionality of the expressed protein was evaluated in an appropriate ex vivo aortic vessel model. Decreased MMP-9 activity was detected using in situ zymography 24 h and 48 h post microinjection of 5 µg TIMP-1 mRNA into the aortic vessel wall. These results suggest that TIMP-1 mRNA administration is a promising approach for the treatment of aneurysms.

Batimastat Induces Cytotoxic and Cytostatic Effects in In Vitro Models of Hematological Tumors.

The role of metalloproteinases (MMPs) in hematological malignancies, like acute myeloid leukemia (AML), myelodysplastic neoplasms (MDS), and multiple myeloma (MM), is well-documented, and these pathologies remain with poor outcomes despite treatment advancements. In this study, we investigated the effects of batimastat (BB-94), an MMP inhibitor (MMPi), in single-administration and daily administration schemes in AML, MDS, and MM cell lines. We used four hematologic neoplasia cell lines: the HL-60 and NB-4 cells as AML models, the F36-P cells as an MDS model, and the H929 cells as a model of MM. We also tested batimastat toxicity in a normal human lymphocyte cell line (IMC cells). BB-94 decreases cell viability and density in a dose-, time-, administration-scheme-, and cell-line-dependent manner, with the AML cells displaying higher responses. The efficacy in inducing apoptosis and cell cycle arrests is dependent on the cell line (higher effects in AML cells), especially with lower daily doses, which may mitigate treatment toxicity. Furthermore, BB-94 activated apoptosis via caspases and ERK1/2 pathways. These findings highlight batimastat's therapeutic potential in hematological malignancies, with daily dosing emerging as a strategy to minimize adverse effects.

Inhibition of MMP-2 and MMP-9 by Dietary Antioxidants in THP-1 Macrophages and Sera from Patients with Breast Cancer.

Polyphenols, the main antioxidants of diet, have shown anti-inflammatory, antioxidant and anticarcinogenic activities. Here, we compared the effects of four polyphenolic compounds on ROS production and on the levels of matrix metalloproteinase (MMP)-2 and -9, which represent important pathogenetic factors of breast cancer. THP-1 differentiated macrophages were activated by LPS and simultaneously treated with different doses of a green tea extract (GTE), resveratrol (RSV), curcumin (CRC) and an olive fruit extract (oliplus). By using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, we found that all of the tested compounds showed antioxidant activity in vitro. In addition, GTE, RSV and CRC were able to counteract ROS production induced by H2O2 in THP-1 cells. As assessed by a zymographic analysis of THP-1 supernatants and by an "in-gel zymography" of a pool of sera from patients with breast cancer, the antioxidant compounds used in this study inhibited both the activity and expression of MMP-2 and MMP-9 through different mechanisms related to their structures and to their ability to scavenge ROS. The results of this study suggest that the used antioxidants could be promising agents for the prevention and complementary treatment of breast cancer and other diseases in which MMPs play a pivotal role.

Control of tissue morphogenesis by the HOX gene Ultrabithorax.

Mutations in the Ultrabithorax (Ubx) gene cause homeotic transformation of the normally two-winged Drosophila into a four-winged mutant fly. Ubx encodes a HOX family transcription factor that specifies segment identity, including transformation of the second set of wings into rudimentary halteres. Ubx is known to control the expression of many genes that regulate tissue growth and patterning, but how it regulates tissue morphogenesis to reshape the wing into a haltere is still unclear. Here, we show that Ubx acts by repressing the expression of two genes in the haltere, Stubble and Notopleural, both of which encode transmembrane proteases that remodel the apical extracellular matrix to promote wing morphogenesis. In addition, Ubx induces expression of the Tissue inhibitor of metalloproteases in the haltere, which prevents the basal extracellular matrix remodelling necessary for wing morphogenesis. Our results provide a long-awaited explanation for how Ubx controls morphogenetic transformation.

Matrix metalloproteinase-2 proteolyzes mitofusin-2 and impairs mitochondrial function during myocardial ischemia-reperfusion injury.

During myocardial ischemia and reperfusion (IR) injury matrix metalloproteinase-2 (MMP-2) is rapidly activated in response to oxidative stress. MMP-2 is a multifunctional protease that cleaves both extracellular and intracellular proteins. Oxidative stress also impairs mitochondrial function which is regulated by different proteins, including mitofusin-2 (Mfn-2), which is lost in IR injury. Oxidative stress and mitochondrial dysfunction trigger the NLRP3 inflammasome and the innate immune response which invokes the de novo expression of an N-terminal truncated isoform of MMP-2 (NTT-MMP-2) at or near mitochondria. We hypothesized that MMP-2 proteolyzes Mfn-2 during myocardial IR injury, impairing mitochondrial function and enhancing the inflammasome response. Isolated hearts from mice subjected to IR injury (30 min ischemia/40 min reperfusion) showed a significant reduction in left ventricular developed pressure (LVDP) compared to aerobically perfused hearts. IR injury increased MMP-2 activity as observed by gelatin zymography and increased degradation of troponin I, an intracellular MMP-2 target. MMP-2 preferring inhibitors, ARP-100 or ONO-4817, improved post-ischemic recovery of LVDP compared to vehicle perfused IR hearts. In muscle fibers isolated from IR hearts the rates of mitochondrial oxygen consumption and ATP production were impaired compared to those from aerobic hearts, whereas ARP-100 or ONO-4817 attenuated these reductions. IR hearts showed higher levels of NLRP3, cleaved caspase-1 and interleukin-1ß in the cytosolic fraction, while the mitochondria-enriched fraction showed reduced levels of Mfn-2, compared to aerobic hearts. ARP-100 or ONO-4817 attenuated these changes. Co-immunoprecipitation showed that MMP-2 is associated with Mfn-2 in aerobic and IR hearts. ARP-100 or ONO-4817 also reduced infarct size and cell death in hearts subjected to 45 min ischemia/120 min reperfusion. Following myocardial IR injury, impaired contractile function and mitochondrial respiration and elevated inflammasome response could be attributed, at least in part, to MMP-2 activation, which targets and cleaves mitochondrial Mfn-2. Inhibition of MMP-2 activity protects against cardiac contractile dysfunction in IR injury in part by preserving Mfn-2 and suppressing inflammation.

Matrix Metalloproteinase-Responsive Drug Delivery Systems.

Matrix metalloproteinases (MMPs) are a class of endopeptidases that are dependent on zinc and facilitate the degradation of extracellular matrix (ECM) proteins, thereby playing pivotal parts in human physiology and pathology. MMPs regulate normal tissue and cellular functions, including tissue development, remodeling, angiogenesis, bone formation, and wound healing. Several diseases, including cancer, inflammation, cardiovascular diseases, and nervous system disorders, have been linked to dysregulated expression of specific MMP subtypes, which can promote tumor progression, metastasis, and inflammation. Various MMP-responsive drug delivery and release systems have been developed by harnessing cleavage activities and overexpression of MMPs in affected regions. Herein, we review the structure, substrates, and physiological and pathological functions of various MMPs and highlight the strategies for designing MMP-responsive nanoparticles to improve the targeting efficiency, penetration, and protection of therapeutic payloads.

Enzyme-Responsive Nanoparticles for the Targeted Delivery of an MMP Inhibitor to Acute Myocardial Infarction.

Herein, we have developed a drug-loaded matrix metalloproteinase (MMP)-responsive micellar nanoparticle (NP) intended for minimally invasive intravenous injection during the acute phase of myocardial infarction (MI) and prolonged retention in the heart for small-molecule drug delivery. Peptide-polymer amphiphiles (PPAs) bearing a small-molecule MMP inhibitor (MMPi), PD166793, were synthesized via ring-opening metathesis polymerization (ROMP) and formulated into spherical micelles by transitioning to aqueous solution. The resulting micellar NPs underwent MMP-induced aggregation, demonstrating enzyme responsiveness. Using a rat MI model, we observed that these NPs were capable of successfully extravasating into the infarcted region of the heart where they were retained due to the active, enzyme-mediated targeting, remaining detectable after 1 week post administration without increasing macrophage recruitment. Furthermore, in vitro studies show that these NPs demonstrated successful drug release following MMP treatment and maintained drug bioactivity as evidenced by comparable MMP inhibition to free MMPi. This work establishes a targeted NP platform for delivering small-molecule therapeutics to the heart after MI, opening possibilities for myocardial infarction treatment.

Influence of N-arylsulfonamido d-valine N-substituents on the selectivity and potency of matrix metalloproteinase inhibitors.

To develop matrix metalloproteinase inhibitors (MMPIs) for both therapy and medicinal imaging by fluorescence-based techniques or positron-emission tomography (PET), a small library of eighteen N-substituted N-arylsulfonamido d-valines were synthesized and their potency to inhibit two gelatinases (MMP-2, and MMP-9), two collagenases (MMP-8, and MMP-13) and macrophage elastase (MMP-12) was determined in a Structure-Activity-Relation study with ({4-[3-(5-methylthiophen-2-yl)-1,2,4-oxadiazol-5-yl]phenyl}sulfonyl)-d-valine (1) as a lead. All compounds were shown to be more potent MMP-2/-9 inhibitors (nanomolar range) compared to other tested MMPs. This is a remarkable result considering that a carboxylic acid group is the zinc binding moiety. The compound with a terminal fluoropropyltriazole group at the furan ring (P1' substituent) was only four times less potent in inhibiting MMP-2 activity than the lead compound 1, making this compound a promising probe for PET application (after using a prosthetic group approach to introduce fluorine-18). Compounds with a TEG spacer and a terminal azide or even a fluorescein moiety at the sulfonylamide N atom (P2' substituent) were almost as active as the lead structure 1, making the latter derivative a suitable fluorescence imaging tool.