Selective Inhibition of MMP-2 Does Not Alter Neurological Recovery after Spinal Cord Injury

Teriparatide: an innovative and promising strategy for protecting the blood-spinal cord barrier following spinal cord injury

The blood-spinal cord barrier (BSCB) is disrupted within minutes of spinal cord injury, leading to increased permeability and secondary spinal cord injury, resulting in more severe neurological damage. The preservation of blood-spinal cord barrier following spinal cord injury plays a crucial role in determining the prognosis. Teriparatide, widely used in clinical treatment for osteoporosis and promoting fracture healing, has been found in our previous study to have the effect of inhibiting the expression of MMP9 and alleviating blood-brain barrier disruption after ischemic stroke, thereby improving neurological damage symptoms. However, there are limited research on whether it has the potential to improve the prognosis of spinal cord injury. This article summarizes the main pathological mechanisms of blood-spinal cord barrier disruption after spinal cord injury and its relationship with Teriparatide, and explores the therapeutic potential of Teriparatide in improving the prognosis of spinal cord injury by reducing blood-spinal cord barrier disruption.

Sodium tanshinone IIA sulfonate promotes spinal cord injury repair by inhibiting blood spinal cord barrier disruption in vitro and in vivo

Spinal cord injury (SCI) leads to microvascular damage and the destruction of the blood spinal cord barrier (BSCB), which can progress into secondary injuries, such as apoptosis and necrosis of neurons and glia, culminating in permanent neurological deficits. BSCB restoration is the primary goal of SCI therapy, although very few drugs can repair damaged barrier structure and permeability. Sodium tanshinone IIA sulfonate (STS) is commonly used to treat cardiovascular disease. However, the therapeutic effects of STS on damaged BSCB during the early stage of SCI remain uncertain. Therefore, we exposed spinal cord microvascular endothelial cells to H₂ O₂ and treated them with different doses of STS. In addition to protecting the cells from H₂ O₂ -induced apoptosis, STS also reduced cellular permeability. In the in vivo model of SCI, STS reduced BSCB permeability, relieved tissue edema and hemorrhage, suppressed MMP activation and prevented the loss of tight junction and adherens junction proteins. Our findings indicate that STS treatment promotes SCI recovery, and should be investigated further as a drug candidate against traumatic SCI.

Metabolism of the Selective Matrix Metalloproteinase-9 Inhibitor (R)-ND-336

(R)-ND-336-designated as compound (R)-5-is a highly selective inhibitor of matrix metalloproteinase (MMP)-9 with efficacy in accelerating diabetic wound healing in murine models. (R)-ND-336 belongs to the class of thiirane inhibitors of MMPs and it is currently undergoing Investigation New Drug (IND)-enabling studies. We investigated the in vitro metabolism of (R)-ND-336 using S9 fractions obtained from mice, rats, dogs, minipigs, monkeys, and humans in order to select the rodent and nonrodent species for toxicology studies. Three metabolites were observed. One metabolite, M3, was observed across all species. Metabolite M2 was found in rats, monkeys, and humans. Metabolite M1 was observed only in rats. The identities of the metabolites were suggested by liquid chromatography/tandem mass spectroscopy (LC/MS-MS) analyses, which were authenticated by comparison to synthetic samples. Metabolites M2 and M3 arise from oxidative deamination of (R)-ND-336 by monoamine oxidase to give the arylaldehyde as a transient (and unobserved) intermediate. Reductive metabolism of this aldehyde gives the alcohol metabolite M2, while further oxidative metabolism of the aldehyde produces the carboxylate metabolite M3. A minor route of metabolism, seen only in rats, is N-acetylation of (R)-ND-336 to give the acetamide M1. The metabolism of (R)-ND-336 is distinctly different from that of the prototype member of this thiirane class ((±)-1, lacking the 4-aminomethyl aryl substituent) which is metabolized primarily by oxidation α to the sulfone to lead to a benzenesulfinate metabolite. All three metabolites are poorer MMP-9 inhibitors, compared to (R)-ND-336 (MMP-9, K _i = 19 nM): M3, MMP-9 IC₅₀ > 100 μM; M2, K _i = 390 nM; and M1, IC₅₀ > 100 μM). The rat and the minipig were selected as the rodent and nonrodent species, respectively, for toxicology studies.

Perspectives and New Aspects of Metalloproteinases' Inhibitors in the Therapy of CNS Disorders: From Chemistry to Medicine

Matrix metalloproteinases (MMPs) play a key role in remodeling of the extracellular matrix (ECM) and, at the same time, influence cell differentiation, migration, proliferation, and survival. Their importance in a variety of human diseases including cancer, rheumatoid arthritis, pulmonary emphysema and fibrotic disorders has been known for many years but special attention should be paid on the role of MMPs in the central nervous system (CNS) disorders. Till now, there are not many well documented physiological MMP target proteins in the brain but only some pathological ones. Numerous neurodegenerative diseases are a consequence of or result in disturbed remodeling of brain ECM, therefore proper action of MMPs as well as control of their activity may play crucial roles in the development of these diseases. In the present review, we discuss the role of metalloproteinase inhibitors, from the wellknown natural endogenous tissue inhibitors of metalloproteinases (TIMPs) to the exogenous synthetic ones like (4-phenoxyphenylsulfonyl)methylthiirane (SB-3CT), tetracyclines, batimastat (BB-94) and FN-439. As the MMP-TIMP system has been well described in physiological development as well as in pathological conditions mainly in neoplastic diseases, the knowledge about the enzymatic system in mammalian brain tissue still remains poorly understood in this context. Therefore, we focus on MMPs inhibition in the context of the physiological function of the adult brain as well as pathological conditions including neurodegenerative diseases, brain injuries, and others.

Serum Level of Metalloproteinase-2 but not Metalloproteinase-9 Rises in Patients With Failed Back Surgery Syndrome After Spinal Cord Stimulation

OBJECTIVES

The impact of spinal cord stimulation (SCS) on serum levels of metalloproteinase-2 (MMP-2) and metalloproteinase-9 (MMP-9) was assessed in a group of patients with failed back surgery syndrome (FBSS). The study was to give new insights into the SCS mechanism of action and the role of MMP-2 and MMP-9 in the development of NP.

MATERIAL AND METHODS

Clinical assessments were performed and biochemical markers were determined in two groups of patients: the control group (24 individuals) and the FBSS group (24 patients). Seventeen patients with the FBSS had SCS implanted and were examined before surgical procedure, one month after (17 patients), and three months after operation (12 patients). Clinical status was assessed with the use numeric rating scale, pain rating index of McGill pain questionnaire, Oswestry disability index and Beck depression inventory. MMP-2 and MMP-9 serum levels were determined using gelatin zymography. Immunoenzymatic method was employed to determine plasma concentrations of tissue inhibitors of metalloproteinases (TIMPs).

RESULTS

Levels of MMP-2 and TIMP-2 were higher in the FBSS group compared to the control group. The difference was statistically significant (p < 0.001 and p = 0.004, respectively). The concentration of MMP-2 was significantly increased (p = 0.0135) one-month post-SCS and remained elevated but stable up to three months after implantation. TIMP-2, MMP-2/TIMP-2, MMP-9, TIMP-1, and MMP-9/TIMP-1 serum levels did not change significantly.

CONCLUSIONS

MMPs may play a role in the development of FBSS. SCS increases the already elevated MMP-2 serum levels which are associated with neuroinflammatory processes in FBSS patients.

In Search of Selectivity in Inhibition of ADAM10

The metalloproteinase ADAM10 has been reported as an important target for drug discovery in several human diseases. In this vein, (6S,7S)-N-hydroxy-5-methyl-6-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazine-1-carbonyl)-5-azaspiro[2.5]octane-7-carboxamide (compound 1) has been reported as a selective ADAM10 inhibitor. We synthesized this compound and document that it lacks both potency and selectivity in inhibition of ADAM10. This finding necessitated a structure-based computational analysis to investigate potency and selectivity of ADAM10 inhibition. The model that emerged indeed excluded compound 1 as an inhibitor for ADAM10, while suggesting another reported compound, (1R,3S,4S)-3-(hydroxycarbamoyl)-4-(4-phenylpiperidine-1-carbonyl)cyclohexyl pyrrolidine-1-carboxylate (compound 2), as an ADAM10 selective inhibitor. Compound 2 was synthesized and its potency, and selectivity in inhibition of ADAM10 were documented with a panel of several related enzymes. Pharmacokinetic studies of compound 2 in mice documented that the compound crosses the blood-brain barrier and may be useful as a pharmacological agent or mechanistic tool to delineate the role of ADAM10 in neurological diseases.

Smell of cells: Volatile profiling of stem- and non-stem cell proliferation

Bacterial and cell cultures are known to emit a large number of volatile organic compounds (VOCs). Conventional biochemical methods are often destructive, time-consuming and expensive. In contrast, VOC analysis of headspace over cultures may offer a non-destructive alternative for the monitoring of cell proliferation and metabolism. VOC profiles from cultures of murine pluripotent stem cells and fibroblasts were assessed every 24 h for 3 days. Pure cell media were measured as parallel controls. VOC analysis was highly standardized with respect to time of measurement and phases of cell growth. Cultures were grown in custom-made inert boxes. In order to determine the effects of fresh media supply on VOC emissions, both cell types were cultured with and without daily media exchange. VOCs from headspace were preconcentrated by means of needle trap micro-extraction and analysed by gas chromatography-mass spectrometry (GC-MS). Murine pluripotent stem cells emitted increasing concentrations of thiirane and methyl-methoxy-hydroxy-methyl-amine (MMHA). Substance concentration correlated with cell numbers. Murine fibroblasts did not emit thiirane or MMHA. Concentrations of aldehydes, especially benzaldehyde, were lower in both cell cultures than in pure media samples. Daily media exchange resulted in higher cell numbers, but had no major effects on VOC concentrations emitted from the cells. Investigation and monitoring of volatile substances such as thiirane and MMHA may enhance the understanding of stem cell properties and lead to a destruction-free characterization of pluripotent stem cells.

Selective small-molecule inhibitors as chemical tools to define the roles of matrix metalloproteinases in disease

The focus of this article is to highlight novel inhibitors and current examples where the use of selective small-molecule inhibitors has been critical in defining the roles of matrix metalloproteinases (MMPs) in disease. Selective small-molecule inhibitors are surgical chemical tools that can inhibit the targeted enzyme; they are the method of choice to ascertain the roles of MMPs and complement studies with knockout animals. This strategy can identify targets for therapeutic development as exemplified by the use of selective small-molecule MMP inhibitors in diabetic wound healing, spinal cord injury, stroke, traumatic brain injury, cancer metastasis, and viral infection. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.

The thiirane-based selective MT1-MMP/MMP2 inhibitor ND-322 reduces melanoma tumor growth and delays metastatic dissemination

MT1-MMP and MMP2 have been implicated as pro-tumorigenic and pro-metastatic factors in a wide variety of cancers including melanoma. We have previously demonstrated that MT1-MMP is highly expressed in melanoma where it promotes melanoma cell invasion and metastasis in part through the activation of its target MMP2. Given the accessibility of MMPs, as they are either secreted (e.g. MMP2) or membrane-tethered (e.g. MT1-MMP), they represent ideal targets for specific inhibition via small molecules. Here we show that the novel small-molecule inhibitor ND-322 with high selectivity for MT1-MMP and MMP2, effectively inhibits MT1-MMP and MMP2 activity resulting in reduced in vitro melanoma cell growth, migration and invasion. Importantly, these inhibitory effects lead to significant reduction of melanoma tumor growth and metastasis. We further show that while cell migration and invasion could be similarly hampered by specific inhibition of either MT1-MMP or MMP2 via shRNAs, the growth inhibitory activity of ND-322 could only be mirrored by specific inhibition of MT1-MMP. These data support ND-322 as a novel effective inhibitor capable of counteracting both MT1-MMP and MMP2, two key proteases involved in melanoma growth and metastasis. ND-322 may therefore represent a new inhibitor in the repertoire of treatments against melanoma.