Beta-aryl-succinic acid hydroxamates as dual inhibitors of matrix metalloproteinases and tumor necrosis factor alpha converting enzyme

Fuentes L, Pimenta A, Nagem RAP, Chávez-Olórtegui C, Schneider FS, Molina F, Sanchez EF, Suárez D, Ferreira RS. Assessing the Interactions between Snake Venom Metalloproteinases and Hydroxamate Inhibitors Using Kinetic and ITC Assays, Molecular Dynamics Simulations and MM/PBSA-Based Scoring Functions

Bothrops species are the main cause of snake bites in rural communities of tropical developing countries of Central and South America. Envenomation by Bothrops snakes is characterized by prominent local inflammation, hemorrhage and necrosis as well as systemic hemostatic disturbances. These pathological effects are mainly caused by the major toxins of the viperidae venoms, the snake venom metalloproteinases (SVMPs). Despite the antivenom therapy efficiency to block the main toxic effects on bite victims, this treatment shows limited efficacy to prevent tissue necrosis. Thus, drug-like inhibitors of these toxins have the potential to aid serum therapy of accidents inflicted by viper snakes. Broad-spectrum metalloprotease inhibitors bearing a hydroxamate zinc-binding group are potential candidates to improve snake bites therapy and could also be used to study toxin-ligand interactions. Therefore, in this work, we used both docking calculations and molecular dynamics simulations to assess the interactions between six hydroxamate inhibitors and two P-I SVMPs selected as models: Atroxlysin-I (hemorrhagic) from Bothrops atrox, and Leucurolysin-a (nonhemorrhagic) from Bothrops leucurus. We also employed a large variety of end-point free energy methods in combination with entropic terms to produce scoring functions of the relative affinities of the inhibitors for the toxins. Then we identified the scoring functions that best correlated with experimental data obtained from kinetic activity assays. In addition, to the characterization of these six molecules as inhibitors of the toxins, this study sheds light on the main enzyme-inhibitor interactions, explaining the broad-spectrum behavior of the inhibitors, and identifies the energetic and entropic terms that improve the performance of the scoring functions.

P-Stereogenic Ir-MaxPHOX: A Step toward Privileged Catalysts for Asymmetric Hydrogenation of Nonchelating Olefins

The Ir-MaxPHOX-type catalysts demonstrated high catalytic performance in the hydrogenation of a wide range of nonchelating olefins with different geometries, substitution patterns, and degrees of functionalization. These air-stable and readily available catalysts have been successfully applied in the asymmetric hydrogenation of di-, tri-, and tetrasubstituted olefins (ee's up to 99%). The combination of theoretical calculations and deuterium labeling experiments led to the uncovering of the factors responsible for the enantioselectivity observed in the reaction, allowing the rationalization of the most suitable substrates for these Ir-catalysts.

Inhibition of hepatocellular carcinoma cell proliferation, migration, and invasion by a disintegrin and metalloproteinase-17 inhibitor TNF484

Background

The aim of this study was to test the effect of TNF484 on cell proliferation, migration, and invasion of hepatocellular carcinoma (HCC) cells.

Materials and Methods

Various doses (0, 1, 10, 50, and 100 nM) of TNF484 were applied to the HepG2 and Bel7402 cells, and cell proliferation was measured by using 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay after 72 h. Cell migration rate was measured using the xCELLigence system, and the cell invasion ability was examined by the three-dimensional spheroid BME cell invasion assay. The expression level of ADAM17 was also measured with RT-PCR.

Results

With the treatment of TNF484, the cell proliferation of HepG2 and Bel7402 cells was inhibited in a dose-dependent manner. Moreover, under TNF484 treatment, the cell migration rate as well as cell invasion ability of the HepG2 and Bel7402 cells were suppressed.

Conclusion

TNF484 could inhibit the cell proliferation, migration, and invasion of some HCC cell lines, making it a potential therapeutic option for liver cancer treatment.

Shedding of klotho by ADAMs in the kidney

The anti-aging gene klotho plays an important role in Ca(2+) and phosphate homeostasis. Membrane-bound klotho is an essential coreceptor for fibroblast growth factor-23 and can be cleaved by proteases, including a disintegrin and metalloproteinase (ADAM)10 and ADAM17. Cleavage of klotho occurs at a site directly above the plasma membrane (α-cut) or between the KL1 and KL2 domain (β-cut), resulting in soluble full-length klotho or KL1 and KL2 fragments, respectively. The aim of the present study was to gain insights into the mechanisms behind klotho cleavage processes in the kidney. Klotho shedding was demonstrated using a Madin-Darby canine kidney cell line stably expressing klotho and human embryonic kidney-293 cells transiently transfected with klotho. Here, we report klotho expression on both the basolateral and apical membrane, with a higher abundance of klotho at the apical membrane and in the apical media. mRNA expression of ADAM17 and klotho were enriched in mouse distal convoluted and connecting tubules. In vitro ADAM/matrix metalloproteinase inhibition by TNF484 resulted in a concentration-dependent inhibition of the α-cut, with a less specific effect on β-cut shedding. In vivo TNF484 treatment in wild-type mice did not change urinary klotho levels. However, ADAM/matrix metalloproteinase inhibition did increase renal and duodenal mRNA expression of phosphate transporters, whereas serum phosphate levels were significantly decreased. In conclusion, our data show that renal cells preferentially secrete klotho to the apical side and suggest that ADAMs are responsible for α-cut cleavage.

Lead optimization of 5-amino-6-(2,2-dimethyl-5-oxo-4-phenylpiperazin-1-yl)-4-hydroxyhexanamides to reduce a cardiac safety issue: discovery of DS-8108b, an orally active renin inhibitor

With the aim to address an undesired cardiac issue observed with our related compound in the recently disclosed novel series of renin inhibitors, further chemical modifications of this series were performed. Extensive structure-activity relationships studies as well as in vivo cardiac studies using the electrophysiology rat model led to the discovery of clinical candidate trans-adamantan-1-ol analogue 56 (DS-8108b) as a potent renin inhibitor with reduced potential cardiac risk. Oral administration of single doses of 3 and 10 mg/kg of 56 in cynomolgus monkeys pre-treated with furosemide led to significant reduction of mean arterial blood pressure for more than 12 h.

Discovery of DS-8108b, a Novel Orally Bioavailable Renin Inhibitor

A novel orally bioavailable renin inhibitor, DS-8108b (5), showing potent renin inhibitory activity and excellent in vivo efficacy is described. We report herein the synthesis and pharmacological effects of 5 including renin inhibitory activity in vitro, suppressive effects of ex vivo plasma renin activity (PRA) in cynomolgus monkey, pharmacokinetic data, and blood pressure-lowering effects in an animal model. Compound 5 demonstrated inhibitory activities toward human renin (IC50 = 0.9 nM) and human and monkey PRA (IC50 = 1.9 and 6.3 nM, respectively). Oral administration of single doses of 3 and 10 mg/kg of 5 in cynomolgus monkey on pretreatment with furosemide led to dose-dependent significant reductions in ex vivo PRA and sustained lowering of mean arterial blood pressure for more than 12 h.

ADAM17 up-regulation in renal transplant dysfunction and non-transplant-related renal fibrosis

BACKGROUND

Interstitial fibrosis and tubular atrophy (IF/TA) is an important cause of renal function loss and ischaemia-reperfusion (I/R) injury is considered to play an important role in its pathophysiology. The aim of the present study was to investigate the role of a disintegrin and metalloproteinase 17 (ADAM17) in human renal allograft disease and in experimental I/R injury of the kidney.

METHODS

We studied the expression of ADAM17 messenger RNA (mRNA) in IF/TA and control kidneys by reverse transcription-polymerase chain reaction and in situ hybridization. Moreover, we assessed ADAM17-mediated heparin-binding epidermal growth factor (HB-EGF) shedding in immortalized human cells. Finally, we studied the effect of pharmacological ADAM17 inhibition in a model of renal I/R injury in rats.

RESULTS

ADAM17 mRNA was up-regulated in IF/TA when compared to control kidneys. In normal kidneys, ADAM17 mRNA was weakly expressed in proximal tubules, peritubular capillaries, glomerular endothelium and parietal epithelium. In IF/TA, tubular, capillary and glomerular ADAM17 expression was strongly enhanced with de novo expression in the mesangium. In interstitial fibrotic lesions, we observed co-localization of ADAM17 with HB-EGF protein. In vitro, inhibition of ADAM17 with TNF484 resulted in a dose-dependent reduction of HB-EGF shedding in phorbol 12-myrisate 13-acetate-stimulated cells and non-stimulated cells. In vivo, ADAM17 inhibition significantly reduced the number of glomerular and interstitial macrophages at Day 4 of reperfusion.

CONCLUSIONS

In conclusion, HB-EGF co-expresses with ADAM17 in renal interstitial fibrosis, suggesting a potential interaction in IF/TA. Targeting ADAM17 to reduce epidermal growth factor receptor phosphorylation could be a promising way of intervention in human renal disease.

LPA-producing enzyme PA-PLA₁α regulates hair follicle development by modulating EGFR signalling

Recent genetic studies of human hair disorders have suggested a critical role of lysophosphatidic acid (LPA) signalling in hair follicle development, mediated by an LPA-producing enzyme, phosphatidic acid-selective phospholipase A(1)α (PA-PLA(1)α, also known as LIPH), and a recently identified LPA receptor, P2Y5 (also known as LPA(6)). However, the underlying molecular mechanism is unknown. Here, we show that epidermal growth factor receptor (EGFR) signalling underlies LPA-induced hair follicle development. PA-PLA(1)α-deficient mice generated in this study exhibited wavy hairs due to the aberrant formation of the inner root sheath (IRS) in hair follicles, which resembled mutant mice defective in tumour necrosis factor α converting enzyme (TACE), transforming growth factor α (TGFα) and EGFR. PA-PLA(1)α was co-localized with TACE, TGFα and tyrosine-phosphorylated EGFR in the IRS. In PA-PLA(1)α-deficient hair follicles, cleaved TGFα and tyrosine-phosphorylated EGFR, as well as LPA, were significantly reduced. LPA, P2Y5 agonists and recombinant PA-PLA(1)α enzyme induced P2Y5- and TACE-mediated ectodomain shedding of TGFα through G12/13 pathway and consequent EGFR transactivation in vitro. These data demonstrate that a PA-PLA(1)α-LPA-P2Y5 axis regulates differentiation and maturation of hair follicles via a TACE-TGFα-EGFR pathway, thus underscoring the physiological importance of LPA-induced EGFR transactivation.

Novel P2-P4 macrocyclic inhibitors of HCV NS3/4A protease by P3 succinamide fragment depeptidization strategy

Hepatitis C represents a serious worldwide health-care problem. Recently, we have disclosed a novel class of P2-P4 macrocyclic inhibitors of NS3/4A protease containing a carbamate functionality as capping group at the P3 N-terminus. Herein we report our work aimed at further depeptidizing the P3 region by replacement of the urethane function with a succinamide motif. This peptidomimetic approach has led to the discovery of novel P2-P4 macrocyclic inhibitors of HCV NS3/4A protease with sub-nanomolar enzyme affinities. In addition to being potent inhibitors of HCV subgenomic replication, optimized analogues within this series have also presented attractive PK properties and showed promising liver levels in rat following oral administration.

ADAM17 upregulation in human renal disease: a role in modulating TGF-alpha availability?

A disintegrin and metalloproteinase (ADAM)17 sheds growth factors from the cell membrane, including epidermal growth factor receptor (EGFR) ligand transforming growth factor (TGF)-alpha. In mice, angiotensin II infusion induces renal fibrosis via ADAM17-mediated TGF-alpha shedding and subsequent EGFR activation. Pharmacological ADAM17 inhibition reduced renal fibrotic lesions and improved renal function, positioning ADAM17 as a promising target of intervention in renal disease. We studied ADAM17 expression in the human kidney. ADAM17 mRNA was constitutively expressed in normal adult kidneys, with highest expression in distal tubules. In human renal disease, ADAM17 was de novo expressed in proximal tubules, peritubular capillaries, and glomerular mesangium and upregulated in podocytes. Glomerular mesangial and endothelial ADAM17 were associated with mesangial matrix expansion, focal glomerulosclerosis, and glomerular macrophage infiltration (P < 0.01). Peritubular capillary and proximal tubular ADAM17 were associated with interstitial fibrosis and interstitial macrophage infiltration (P < 0.05). Both glomerular and interstitial ADAM17 were associated with decreased renal function (P < 0.05). In renal fibrosis, ADAM17 colocalized with TGF-alpha. Moreover, in cultured human podocytes and proximal tubular cells, pharmacological ADAM17 inhibition reduced constitutive TGF-alpha shedding by 78% (P < 0.005) and 100% (P < 0.05), respectively, and phorbol ester-induced TGF-alpha shedding by 84% (P < 0.005) and 92% (P = 0.005), respectively. Finally, ADAM17 inhibition reduced cellular proliferation. In conclusion, the ADAM17 expression pattern and its role in shedding TGF-alpha from cultured human kidney cells suggest a role in the development of fibrosis. Since EGFR signaling is implicated in renal fibrosis, targeting ADAM17 to reduce availability of EGFR ligand TGF-alpha may represent a promising way of intervention in human renal disease.

Synthesis and activity of tryptophan sulfonamide derivatives as novel non-hydroxamate TNF-alpha converting enzyme (TACE) inhibitors

A novel series of non-hydroxamate tryptophan sulfonamide derivatives containing a butynyloxy P1' moiety was identified as inhibitors of TNF-alpha converting enzyme (TACE). The structure-activity relationship of the series was examined via substitution on the tryptophan indole ring. Of the compounds investigated, 2-(4-(but-2-ynyloxy)phenylsulfonamido)-3-(1-(4-methoxybenzyl)-1H-indol-3-yl)propanoic acid (12p) has the best in vitro potency against isolated TACE enzyme with an IC(50) of 80 nM. Compound 12p also shows good selectivity over MMP-1, -13, -14.

Intermolecular enolate heterocoupling: scope, mechanism, and application

This full account presents the background on, discovery of, and extensive insight that has been gained into the oxidative intermolecular coupling of two different carbonyl species. Optimization of this process has culminated in reliable and scalable protocols for the union of amides, imides, ketones, and oxindoles using soluble copper(II) or iron(III) salts as oxidants. Extensive mechanistic studies point to a metal-chelated single-electron-transfer process in the case of copper(II), while iron(III)-based couplings appear to proceed through a non-templated heterodimerization. This work presents the most in-depth findings on the mechanism of oxidative enolate coupling to date. The scope of oxidative enolate heterocoupling is extensive (40 examples) and has been shown to be efficient even on a large scale (gram-scale or greater). Finally, the method has been applied to the total synthesis of the unsymmetrical lignan lactone (-)-bursehernin and a medicinally important 2,3-disubstituted succinate derivative.

Design and synthesis of 3,3-piperidine hydroxamate analogs as selective TACE inhibitors

Structure-based methods were used to design beta-sulfone 3,3-piperidine hydroxamates as TACE inhibitors with the aim of improving selectivity for TACE versus MMP-13. Several compounds in this series were synthesized and evaluated in enzymatic and cell-based assays. These analogs exhibit excellent in vitro potency against isolated TACE enzyme and show good selectivity for TACE over the related metalloproteases MMP-2, -13, and -14.

Adjuvant TACE inhibitor treatment improves the outcome of TLR2-/- mice with experimental pneumococcal meningitis

Background

Streptococcus (S.) pneumoniae meningitis has a high lethality despite antibiotic treatment. Inflammation is a major pathogenetic factor, which is unresponsive to antibiotics. Therefore adjunctive therapies with antiinflammatory compounds have been developed. TNF484 is a TNF-alpha converting enzyme (TACE) inhibitor and has been found efficacious in experimental meningitis. Toll-like receptor 2 (TLR2) contributes to host response in pneumococcal meningitis by enhancing bacterial clearing and downmodulating inflammation. In this study, TNF484 was applied in mice, which lacked TLR2 and exhibited a strong meningeal inflammation.

Methods

10³ CFU S. pneumoniae serotype 3 was inoculated subarachnoidally into C57BL/6 wild type (wt) mice or TLR2^-/-, CD14^-/- and CD14^-/-/TLR2^-/- mice. Severity of disease and survival was followed over 9 days. Response to antibiotics (80 mg/kg ceftriaxone i.p. for 5 days) and/or TACE inhibitor treatment (1 mg/kg s.c. twice daily for 4 days) was evaluated. Animals were sacrificed after 12, 24, and 48 h for analysis of bacterial load in cerebrospinal fluid (CSF) and brain and for TNF and leukocyte measurements in CSF.

Results

TLR2^-/- mice were significantly sicker than the other mouse strains 24 h after infection. All knockout mice showed higher disease severity after 48 h and died earlier than wt mice. TNF release into CSF was significantly more elevated in TLR2^-/- than in the other strains after 24 h. Brain bacterial numbers were significantly higher in all knockout than wt mice after 24 h. Modulation of outcome by antibiotic and TACE inhibitor treatment was evaluated. With antibiotic therapy all wt, CD14^-/- and TLR2^-/-/CD14^-/- mice, but only 79% of TLR2^-/- mice, were rescued. TACE inhibitor treatment alone did not rescue, but prolonged survival in wt mice, and in TLR2^-/- and CD14^-/- mice to the values observed in untreated wt mice. By combined antibiotic and TACE inhibitor treatment 95% of TLR2^-/- mice were rescued.

Conclusion

During pneumococcal meningitis strong inflammation in TLR2-deficiency was associated with incomplete responsiveness to antibiotics and complete response to combined antibiotic and TACE inhibitor treatment. TACE inhibitor treatment offers a promising adjuvant therapeutic strategy in pneumococcal meningitis.

Synthesis and SAR of succinamide peptidomimetic inhibitors of cathepsin S

Peptidic, non-covalent inhibitors of lysosomal cysteine protease cathepsin S (1 and 2) were investigated due to low oral bioavailability, leading to an improved series of peptidomimetic inhibitors. Utilizing phenyl succinamides as the P2 residue increased the oral exposure of this lead series of compounds, while retaining selective inhibition of the cathepsin S isoform. Concurrent investigation of the P1 and P2 subsites resulted in the discovery of several potent and selective inhibitors of cathepsin S with good pharmacokinetic properties due to the elimination of saturated aliphatic P2 residues.

Doxycycline reduces mortality and injury to the brain and cochlea in experimental pneumococcal meningitis

Bacterial meningitis is characterized by an inflammatory reaction to the invading pathogens that can ultimately lead to sensorineural hearing loss, permanent brain injury, or death. The matrix metalloproteinases (MMPs) and tumor necrosis factor alpha-converting enzyme (TACE) are key mediators that promote inflammation, blood-brain barrier disruption, and brain injury in bacterial meningitis. Doxycycline is a clinically used antibiotic with anti-inflammatory effects that lead to reduced cytokine release and the inhibition of MMPs. Here, doxycycline inhibited TACE with a 50% inhibitory dose of 74 microM in vitro and reduced the amount of tumor necrosis factor alpha released into the cerebrospinal fluid by 90% in vivo. In an infant rat model of pneumococcal meningitis, a single dose of doxycycline (30 mg/kg) given as adjuvant therapy in addition to ceftriaxone 18 h after infection significantly reduced the mortality, the blood-brain barrier disruption, and the extent of cortical brain injury. Adjuvant doxycycline (30 mg/kg given subcutaneously once daily for 4 days) also attenuated hearing loss, as assessed by auditory brainstem response audiometry, and neuronal death in the cochlear spiral ganglion at 3 weeks after infection. Thus, doxycycline, probably as a result of its anti-inflammatory properties, had broad beneficial effects in the brain and the cochlea and improved survival in this model of pneumococcal meningitis in infant rats.

Design and synthesis of butynyloxyphenyl β-sulfone piperidine hydroxamates as TACE inhibitors

A series of butynyloxyphenyl beta-sulfone piperidine hydroxamate TACE inhibitors was designed and synthesized. The resulting structure-activity relationship and MMP selectivity of the series were examined. Of the compounds investigated, 17s has excellent in vitro potency against isolated TACE enzyme, shows good selectivity over MMP-1, -2, -7, -8, -9, -13, and -14, and oral activity in an in vivo mouse model of TNF-alpha production.

A cassette-dosing approach for improvement of oral bioavailability of dual TACE/MMP inhibitors

The structural features contributing to the different pharmacokinetic properties of the TACE/MMP inhibitors TNF484 and Trocade were analyzed using an in vivo cassette-dosing approach in rats. This enabled us to identify a new lead compound with excellent pharmacokinetic properties, but weaker activity on the biological targets. Directed structural modifications maintained oral bioavailability and restored biological activity, leading to a novel compound almost equipotent to TNF484 in vivo, but with a more than tenfold higher oral bioavailability.

Acetylenic TACE inhibitors. Part 2: SAR of six-membered cyclic sulfonamide hydroxamates

The SAR of a series of potent sulfonamide hydroxamate TACE inhibitors bearing a butynyloxy P1' group was explored. In particular, compound 5k has excellent in vitro potency against TACE enzyme and in cells, and oral activity in an in vivo model of TNF-alpha production and a collagen-induced arthritis model.

A comparison of the binding sites of matrix metalloproteinases and tumor necrosis factor-alpha converting enzyme: implications for selectivity

MMPs and TACE (ADAM-17) assume independent, parallel, or opposite pathological roles in cancer, arthritis, and several other diseases. For therapeutic purposes, selective inhibition of individual MMPs and TACE is required in most cases due to distinct roles in diseases and the need to preserve activities in normal states. Toward this goal, we compared force-field interaction energies of five ubiquitous inhibitor atoms with flexible binding sites of 24 known human MMPs and TACE. The results indicate that MMPs 1-3, 10, 11, 13, 16, and 17 have at least one subsite very similar to TACE. S3 subsite is the best target for development of specific TACE inhibitors. Specific binding to TACE compared to most MMPs is promoted by placing a negatively charged ligand part at the bottom of S2 subsite, at the entrance of S1' subsite, or the part of S3' subsite that is close to catalytic zinc. Numerous other clues, consistent with available experimental data, are provided for design of selective inhibitors.

Zinc metalloproteinase-mediated cleavage of the human Nogo-66 receptor

The central nervous system myelin components oligodendrocyte-myelin glycoprotein, myelin-associated glycoprotein and the Nogo-66 domain of Nogo-A inhibit neurite outgrowth by binding the neuronal glycosyl-phosphatidylinositol-anchored Nogo-66 receptor (NgR) that transduces the inhibitory signal to the cell interior via a transmembrane co-receptor, p75NTR. Here, we demonstrate that human NgR expressed in human neuroblastoma cells is constitutively cleaved in a post-ER compartment to generate a lipid-raft associated C-terminal fragment that is present on the cell surface and a soluble N-terminal fragment that is released into the medium. Mass spectrometric analysis demonstrated that the N-terminal fragment terminated just after the C-terminus of the ligand-binding domain of NgR. In common with other shedding mechanisms, the release of this fragment was blocked by a hydroxamate-based inhibitor of zinc metalloproteinases, but not by inhibitors of other protease classes and up-regulated by treatment with the cellular cholesterol depleting agent methyl-beta-cyclodextrin. The N-terminal fragment bound Nogo-66 and blocked Nogo-66 binding to cell surface NgR but failed to associate with p75NTR, indicative of a role as a Nogo-66 antagonist. Furthermore, the N- and C-terminal fragments of NgR were detectable in human brain cortex and the N-terminal fragment was also present in human cerebrospinal fluid, demonstrating that NgR proteolysis occurs within the human nervous system. Our findings thus identify a potential cellular mechanism for the regulation of NgR function at the level of the receptor.

Synthesis and Structure−Activity Relationships of 4-alkynyloxy Phenyl Sulfanyl, Sulfinyl, and Sulfonyl Alkyl Hydroxamates as Tumor Necrosis Factor-α Converting Enzyme and Matrix Metalloproteinase Inhibitors

A series of 4-alkynyloxy phenyl sulfanyl, sulfinyl and sulfony alkyl and piperidine-4-carboxylic acid hydroxamides were synthesized. Their structure-activity relationships, against tumor necrosis factor-alpha (TACE) and matrix metalloproteinase (MMP) inhibitor activities, are presented by investigating the oxidation state on sulfur and altering the P1' substituent. The sulfonyl derivatives 20-24 carrying a 4-butynyloxy moiety were selective TACE inhibitors over the MMPs tested. The sulfinyl derivatives showed a preference for a specific oxidation on sulfur as in compounds 25-28. The selectivity over MMPs was also demonstrated in the sulfonyl series. The enhanced cellular activity was achieved upon incorporating a butynyloxy substituent in the piperidene series. Compounds 64 and 65 were potent inhibitors of TNF-alpha release in the mouse at 100 mg/kg po.

In pneumococcal meningitis a novel water-soluble inhibitor of matrix metalloproteinases and TNF-α converting enzyme attenuates seizures and injury of the cerebral cortex

Matrix metalloproteinases (MMPs) and TNF-alpha converting enzyme (TACE) contribute to the pathophysiology of bacterial meningitis. To date, MMP-inhibitors studied in models of meningitis were compromised by their hydrophobic nature. We investigated the pharmacokinetics and the effect of TNF484, a water-soluble hydroxamate-based inhibitor of MMP and TACE, on disease parameters and brain damage in a neonatal rat model of pneumococcal meningitis. At 1 mg/kg q6h TNF484 reduced soluble TNF-alpha and the collagen degradation product hydroxyproline in the cerebrospinal fluid. Clinically, TNF484 attenuated the incidence of seizures and was neuroprotective in the cortex. Water-soluble MMP-inhibitors may hold promise in the therapy of bacterial meningitis.

Characterization of Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2, a fluorogenic substrate with increased specificity constants for collagenases and tumor necrosis factor converting enzyme

Matrix metalloproteinases (MMPs) and the related tumor necrosis factor converting enzyme (TACE) are involved in tissue remodeling, cell migration, and processing of signaling molecules, such as cytokines and adhesion molecules. Fluorescence-quenched peptide substrates have been widely used to quantitate the actual enzymatic activity of MMPs. However, the various MMPs have very different specific activities toward these substrates. This restricts their value for the determination of composite proteolytic activity of mixtures of metalloproteinases in biological fluids. The N-terminal elongation of the most widely used MMP substrate (FS-1) with a Lys to the sequence Mca-Lys-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH(2) (FS-6) yields a fluorogenic peptide with improved substrate properties. As compared to FS-1, the specificity constant (kcat/Km) of FS-6 for collagenases (MMP-1, MMP-8, MMP-13) and MT1-MMP (MMP-14) is increased two- to ninefold and threefold, respectively, while those for gelatinases and matrilysin remain equally high. Using high-performance liquid chromatography-fluorescence detection, MMP activity can be quantitated in the picomolar range. FS-6 shows up to twofold higher specificity constants (kcat/Km of 0.8x10(6)M(-1)s(-1)) for TACE, as compared to standard substrates Mca-PLAQAV-Dpa-RSSSAR-NH(2) and Dabcyl-LAQAVRSSSAR-EDANS. FS-6 is fully water soluble and thus allows measurement of metalloproteinase activity in tissue culture conditions, e.g., on the surface of viable cells in situ.

Acetylenic TACE inhibitors. Part 1. SAR of the acyclic sulfonamide hydroxamates

The SAR of a series of potent sulfonamide hydroxamate TACE inhibitors, all bearing a butynyloxy P1' group, was explored. In particular, compound 5j has excellent in vitro potency against isolated TACE enzyme and in cells, good selectivity over MMP-1 and MMP-9, and oral activity in an in vivo model of TNF-alpha production and a collagen-induced arthritis model.

Upcoming biologic agents for the treatment of rheumatic diseases

The development of biologic agents has provided rheumatologists with a variety of new and effective treatment options. The success of early biologics, especially etanercept and infliximab for the treatment of rheumatoid arthritis, has spurred research into novel targets for the management of systemic inflammatory and autoimmune diseases. In addition, existing biologics approved for use in other diseases, such as rituximab, are now under study for the treatment of new indications. This article reviews ongoing research on the treatment of rheumatic diseases with new and existing biologic agents.