Biochemical and pharmacological characterization of 2-(9-(2-piperidinoethoxy)-4-oxo-4H-pyrido[1,2-a]pyrimidin-2-yloxymethyl)-4-(1-methylethyl)-6-methoxy-1,2-benzisothiazol-3(2H)-one-1,1-dioxide (SSR69071), a novel, orally active elastase inhibitor

Comprehensive analysis of scRNA-Seq and bulk RNA-Seq reveals ubiquitin promotes pulmonary fibrosis in chronic pulmonary diseases

It is estimated that there are 544.9 million people suffering from chronic respiratory diseases in the world, which is the third largest chronic disease. Although there are various clinical treatment methods, there is no specific drug for chronic pulmonary diseases, including chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD) and idiopathic pulmonary fibrosis (IPF). Therefore, it is urgent to clarify the pathological mechanism and medication development. Single-cell transcriptome data of human and mouse from GEO database were integrated by "Harmony" algorithm. The data was standardized and normalized by using "Seurat" package, and "SingleR" algorithm was used for cell grouping annotation. The "Findmarker" function is used to find differentially expressed genes (DEGs), which were enriched and analyzed by using "clusterProfiler", and a protein interaction network was constructed for DEGs, and four algorithms are used to find the hub genes. The expression of hub genes were analyzed in independent human and mouse single-cell transcriptome data. Bulk RNA data were used to integrate by the "SVA" function, verify the expression levels of hub genes and build a diagnostic model. The L1000FWD platform was used to screen potential drugs. Through exploring the similarities and differences by integrated single-cell atlas, we found that the lung parenchymal cells showed abnormal oxidative stress, cell matrix adhesion and ubiquitination in COPD, corona virus disease 2019 (COVID-19), ILD and IPF. Meanwhile, the lung resident immune cells showed abnormal Toll-like receptor signals, interferon signals and ubiquitination. However, unlike acute pneumonia (COVID-19), chronic pulmonary disease shows enhanced ubiquitination. This phenomenon was confirmed in independent external human single-cell atlas, but unfortunately, it was not confirmed in mouse single-cell atlas of bleomycin-induced pulmonary fibrosis model and influenza virus-infected mouse model, which means that the model needs to be optimized. In addition, the bulk RNA-Seq data of COVID-19, ILD and IPF was integrated, and we found that the immune infiltration of lung tissue was enhanced, consistent with the single-cell level, UBA52, UBB and UBC were low expressed in COVID-19 and high expressed in ILD, and had a strong correlation with the expression of cell matrix adhesion genes. UBA52 and UBB have good diagnostic efficacy, and salermide and SSR-69071 can be used as their candidate drugs. Our study found that the disorder of protein ubiquitination in chronic pulmonary diseases is an important cause of pathological phenotype of pulmonary fibrosis by integrating scRNA-Seq and bulk RNA-Seq, which provides a new horizons for clinicopathology, diagnosis and treatment.

Proteases and Their Inhibitors in Chronic Obstructive Pulmonary Disease

In the context of respiratory disease, chronic obstructive pulmonary disease (COPD) is the leading cause of mortality worldwide. Despite much development in the area of drug development, currently there are no effective medicines available for the treatment of this disease. An imbalance in the protease: Antiprotease ratio in the COPD lung remains an important aspect of COPD pathophysiology and several studies have shown the efficacy of antiprotease therapy in both in vitro and in vivo COPD models. However more in-depth studies will be required to validate the efficacy of lead drug molecules targeting these proteases. This review discusses the current status of protease-directed drugs used for treating COPD and explores the future prospects of utilizing the potential of antiprotease-based therapeutics as a treatment for this disease.

Therapeutic potential for leukocyte elastase in chronic pain states harboring a neuropathic component

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Inhibitors of leukocyte elastase inhibit spontaneous and evoked pain behaviors in mouse models of chronic pain of neuropathic, cancer, and diabetic origins.

Neuropathic pain is an integral component of several chronic pain conditions and poses a major health problem worldwide. Despite emerging understanding of mechanisms behind neuropathic pain, the available treatment options are still limited in efficacy or associated with side effects, therefore making it necessary to find viable alternatives. In a genetic screen, we recently identified SerpinA3N, a serine protease inhibitor secreted in response to nerve damage by the dorsal root ganglion neurons and we showed that SerpinA3N acts against induction of neuropathic pain by inhibiting the T-cell- and neutrophil-derived protease, leucocyte elastase (LE). In the current study, via detailed in vivo pharmacology combined with analyses of evoked- and spontaneous pain-related behaviors in mice, we report that on systemic delivery, a single dose of 3 independent LE inhibitors can block established nociceptive hypersensitivity in early and late phases in the spared nerve injury model of traumatic neuropathic pain in mice. We further report the strong efficacy of systemic LE inhibitors in reversing ongoing pain in 2 other clinically relevant mouse models—painful diabetic neuropathy and cancer pain. Detailed immunohistochemical analyses on the peripheral tissue samples revealed that both T-Lymphocytes and neutrophils are the sources of LE on peripheral nerve injury, whereas neutrophils are the primary source of LE in diabetic neuropathic conditions. In summary, our results provide compelling evidence for a strong therapeutic potential of generic LE inhibitors for the treatment of neuropathic pain and other chronic pain conditions harboring a neuropathic pain component.

Evaluation of a biomimetic 3D substrate based on the Human Elastin-like Polypeptides (HELPs) model system for elastolytic activity detection

Elastin is a fibrous protein that confers elasticity to tissues such as skin, arteries and lung. It is extensively cross-linked, highly hydrophobic and insoluble. Nevertheless, elastin can be hydrolysed by bacterial proteases in infectious diseases, resulting in more or less severe tissue damage. Thus, development of substrates able to reliably and specifically detect pathogen-secreted elastolytic activity is needed to improve the in vitro evaluation of the injury that bacterial proteases may provoke. In this work, two human biomimetic elastin polypeptides, HELP and HELP1, as well as the matrices derived from HELP, have been probed as substrates for elastolytic activity detection. Thirty strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients were analyzed in parallel with standard substrates, to detect proteolytic and elastolytic activity. Results point to the HELP-based 3D matrix as an interesting biomimetic model of elastin to assess bacterial elastolytic activity in vitro. Moreover, this model substrate enables to further elucidate the mechanism underlying elastin degradation at molecular level, as well as to develop biomimetic material-based devices responsive to external stimuli.

A Workflow to Investigate Exposure and Pharmacokinetic Influences on High-Throughput in Vitro Chemical Screening Based on Adverse Outcome Pathways

BACKGROUND

Adverse outcome pathways (AOPs) link adverse effects in individuals or populations to a molecular initiating event (MIE) that can be quantified using in vitro methods. Practical application of AOPs in chemical-specific risk assessment requires incorporation of knowledge on exposure, along with absorption, distribution, metabolism, and excretion (ADME) properties of chemicals.

OBJECTIVES

We developed a conceptual workflow to examine exposure and ADME properties in relation to an MIE. The utility of this workflow was evaluated using a previously established AOP, acetylcholinesterase (AChE) inhibition.

METHODS

Thirty chemicals found to inhibit human AChE in the ToxCast™ assay were examined with respect to their exposure, absorption potential, and ability to cross the blood-brain barrier (BBB). Structures of active chemicals were compared against structures of 1,029 inactive chemicals to detect possible parent compounds that might have active metabolites.

RESULTS

Application of the workflow screened 10 "low-priority" chemicals of 30 active chemicals. Fifty-two of the 1,029 inactive chemicals exhibited a similarity threshold of ≥ 75% with their nearest active neighbors. Of these 52 compounds, 30 were excluded due to poor absorption or distribution. The remaining 22 compounds may inhibit AChE in vivo either directly or as a result of metabolic activation.

CONCLUSIONS

The incorporation of exposure and ADME properties into the conceptual workflow eliminated 10 "low-priority" chemicals that may otherwise have undergone additional, resource-consuming analyses. Our workflow also increased confidence in interpretation of in vitro results by identifying possible "false negatives."

CITATION

Phillips MB, Leonard JA, Grulke CM, Chang DT, Edwards SW, Brooks R, Goldsmith MR, El-Masri H, Tan YM. 2016. A workflow to investigate exposure and pharmacokinetic influences on high-throughput in vitro chemical screening based on adverse outcome pathways. Environ Health Perspect 124:53-60; http://dx.doi.org/10.1289/ehp.1409450.

Sirtinol inhibits neutrophil elastase activity and attenuates lipopolysaccharide-mediated acute lung injury in mice

Enhanced activity of neutrophil elastase leads to a protease–antiprotease imbalance, and plays an essential pathogenic role in acute lung injury (ALI) and acute respiratory distress syndrome. We assayed the pharmacological effects and mechanisms of the action of sirtinol in human neutrophils, and in neutrophil elastase (HNE)-induced paw edema and lipopolysaccharide (LPS)-mediated ALI in mice. Sirtinol significantly inhibited the activity of HNE from human neutrophils in response to various stimulators. The inhibitory effects on HNE activity were not mediated through protein kinase A, calcium, extracellular-regulated kinase, c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, Akt, or Src family kinases. Analysis of enzymatic activities showed that sirtinol inhibited HNE activity in a concentration-dependent manner. These results demonstrate that sirtinol does not affect neutrophil function and is an HNE inhibitor. In addition, administration of sirtinol significantly inhibited HNE-induced paw edema, and attenuated the myeloperoxidase activity and reduced pulmonary wet/dry weight ratio in the LPS-induced ALI mouse model. Our study indicates that sirtinol has anti-inflammatory effects through direct inhibition of HNE activity and attenuates HNE-induced and LPS-mediated tissue or organ injury in vivo. Sirtinol is a novel HNE inhibitor and may have the potential for clinical application in the treatment of inflammatory lung diseases.

Solar ultraviolet irradiation induces decorin degradation in human skin likely via neutrophil elastase

Exposure of human skin to solar ultraviolet (UV) irradiation induces matrix metalloproteinase-1 (MMP-1) activity, which degrades type I collagen fibrils. Type I collagen is the most abundant protein in skin and constitutes the majority of skin connective tissue (dermis). Degradation of collagen fibrils impairs the structure and function of skin that characterize skin aging. Decorin is the predominant proteoglycan in human dermis. In model systems, decorin binds to and protects type I collagen fibrils from proteolytic degradation by enzymes such as MMP-1. Little is known regarding alterations of decorin in response to UV irradiation. We found that solar-simulated UV irradiation of human skin in vivo stimulated substantial decorin degradation, with kinetics similar to infiltration of polymorphonuclear (PMN) cells. Proteases that were released from isolated PMN cells degraded decorin in vitro. A highly selective inhibitor of neutrophil elastase blocked decorin breakdown by proteases released from PMN cells. Furthermore, purified neutrophil elastase cleaved decorin in vitro and generated fragments with similar molecular weights as those resulting from protease activity released from PMN cells, and as observed in UV-irradiated human skin. Cleavage of decorin by neutrophil elastase significantly augmented fragmentation of type I collagen fibrils by MMP-1. Taken together, these data indicate that PMN cell proteases, especially neutrophil elastase, degrade decorin, and this degradation renders collagen fibrils more susceptible to MMP-1 cleavage. These data identify decorin degradation and neutrophil elastase as potential therapeutic targets for mitigating sun exposure-induced collagen fibril degradation in human skin.

2-[2-(2-Bromo-phen-yl)-2-oxoeth-yl]-1λ(6),2-benzothia-zole-1,1,3-trione

The asymmetric unit of the title compound, C₁₅H₁₀BrNO₄S, contains two different conformers in which the benzisothia­zole rings are essentially planar, with r.m.s. deviations of 0.012 and 0.017 Å. The mean planes of the benzene rings form dihedral angles 70.49 (13) and 72.79 (11)° with the benzisothia­zole rings. The orientation of the Br atoms in the two conformers exhibit the most pronounced difference, with opposing orientations in the two mol­ecules. The crystal structure is stabilized by π–π inter­actions between the benzene rings of the benzisothia­zole moieties of one mol­ecule and bromo­benzene rings of the other mol­ecule, with distances between the ring centroids of 3.599 (3) and 3.620 (3) Å, respectively. The crystal packing is further consolidated by pairs of weak inter­molecular C—H⋯O hydrogen bonds, which form inversion dimers.

Pivotal role for alpha1-antichymotrypsin in skin repair

α1-Antichymotrypsin (α1-ACT) is a specific inhibitor of leukocyte-derived chymotrypsin-like proteases with largely unknown functions in tissue repair. By examining human and murine skin wounds, we showed that following mechanical injury the physiological repair response is associated with an acute phase response of α1-ACT and the mouse homologue Spi-2, respectively. In both species, attenuated α1-ACT/Spi-2 activity and gene expression at the local wound site was associated with severe wound healing defects. Topical application of recombinant α1-ACT to wounds of diabetic mice rescued the impaired healing phenotype. LC-MS analysis of α1-ACT cleavage fragments identified a novel cleavage site within the reactive center loop and showed that neutrophil elastase was the predominant protease involved in unusual α1-ACT cleavage and inactivation in nonhealing human wounds. These results reveal critical functions for locally acting α1-ACT in the acute phase response following skin injury, provide mechanistic insight into its function during the repair response, and raise novel perspectives for its potential therapeutic value in inflammation-mediated tissue damage.

N-Saccharinylmethyl ether

In the title mol-ecule [systematic name: 1,1,1',1'-tetra-oxo-2,2'-(oxydimethyl-ene)bi(1,2-benzothia-zol-3-one)], C(16)H(12)N(2)O(7)S(2), the benzisothia-zole ring systems are individually planar [maximum deviations of 0.0497 (13) and 0.0195 (19) Å] and their mean planes are inclined at a dihedral angle of 62.76 (4)°. The crystal structure is stabilized by weak inter-molecular C-H⋯O inter-actions. Two O atoms bonded to two S atoms and four aryl H atoms belonging to two symmetry-related mol-ecules lying about an inversion center form a hydrogen-bonded 10-membered ring with graph-set notation R(4) (2)(10).

2-[2-(3-Chloro-phen-yl)-2-oxoeth-yl]-1,2-benzisothia-zol-3(2H)-one 1,1-dioxide

In the title compound, C₁₅H₁₀ClNO₄S, the benzothia­zole ring system is essentially planar [maximum deviation = 0.0382 (13) Å for the N atom] and forms a dihedral angle of 74.43 (6)° with the chloro-substituted benzene ring. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds form R₂²(10) and R₂²(16) ring motifs

2-(2-Oxo-2-phenyl-ethyl)-1,2-benziso-thia-zol-3(2H)-one 1,1-dioxide

In the title compound, C₁₅H₁₁NO₄S, the benzothia­zole unit is essentially planar [maximum deviation = 0.0644 (14) Å for the N atom] and forms a dihedral angle 54.43 (6)° with the phenyl ring. In the crystal structure, weak bifurcated C—H⋯O hydrogen bonds involving the carbonyl O atoms as acceptors result in R₂²(7) ring motifs.

2-[2-(3-Methoxy-phen-yl)-2-oxoeth-yl]-1,2-benzisothia-zol-3(2H)-one 1,1-dioxide

In the title compound, C(16)H(13)NO(5)S, the benzothia-zole unit is essentially planar [maximum deviation = 0.0501 (10) Å for the S atom] and is oriented at a dihedral angle of 67.85 (5)° with respect to the meth-oxy-substituted benzene ring. The mean plane of the meth-oxy group is oriented at 14.3 (3)° with respect to the benzene ring to which it is attached. In the crystal structure, weak C-H⋯O hydrogen bonds form macrocyclic rings with R(2) (2)(10) and R(2) (2)(12) motifs.

N-acetonylsaccharin

In the title compound [systematic name: 2-(2-oxoprop­yl)-1,2-benzothia­zol-3(2H)-one 1,1-dioxide], C₁₀H₉NO₄S, the benzo­thia­zole unit is essentially planar [maximum deviation = 0.0490 (9) Å for the S atom] and the oxopropyl group is inclined at an angle 75.61 (8)° with respect to its mean plane. In the crystal, mol­ecules are held together by weak inter­molecular C—H⋯O non-classical hydrogen bonds, resulting in centrosymmetric dimeric units, forming 14-membered ring systems which may be described as R₂²(14) ring motifs. Moreover, mol­ecules lying about inversion centers show π–π inter­actions, with centroid–centroid separations between the benzene rings of 3.676 (2) Å.

2-(Prop-2-en-yl)-1,2-benzisothia-zol-3(2H)-one 1,1-dioxide

In the title compound, C(10)H(9)NO(3)S, the benzisothia-zole group is almost planar (with a maximum deviation of 1.61 Å). The crystal structure is stabilized by weak inter-molecular C-H⋯O hydrogen bonds, forming a chain of mol-ecules along b.

2-[(E)-3-Phenyl-prop-2-en-yl]-1,2-benzisothia-zol-3(2H)-one 1,1-dioxide

In the crystal structure of the title compound, C₁₆H₁₃NO₃S, the benzisothia­zole group is almost planar (r.m.s. deviation for all non-H atoms excluding the two O atoms bonded to S = 0.009 Å). The dihedral angle between the fused ring and the terminal ring is 13.8 (1)°. In the crystal, mol­ecules are linked through inter­molecular C—H⋯O contacts forming a chain of mol­ecules along b.

Methyl 3-oxo-2,3-dihydro-1,2-benzothia-zole-2-acetate 1,1-dioxide

The title mol-ecule, C(10)H(9)NO(5)S, is composed of two essentially planar units with a dihedral angle of 89.16 (6)° between them. In the crystal structure, there are weak inter-molecular C-H⋯O inter-actions resulting in dimeric pairs of mol-ecules about inversion centres and chains of mol-ecules extended along the a and c axes, thus stabilizing the structure. In addition, benzothia-zole rings lying parallel to each other with centroid-centroid distances of 3.679 (2) and 3.999 (2) Å indicate the existence of π-π stacking inter-actions.

Study of human lung elastin degradation by different elastases using high-performance liquid chromatography/mass spectrometry

Elastin is a structural insoluble protein which gives elasticity to tissues and organs. Although its hydrophobic and highly cross-linked nature makes it a very durable polymer, degradation of elastin in relation with several pathological conditions, such as pulmonary emphysema, has been documented. Since different enzymes may be involved in elastolysis, it is of interest to determine which enzyme is responsible for the degradative effects observed in a certain disease. The aim of this work was to study elastin degradation by proteases from different families (serine, cysteine, and metalloproteases) using liquid chromatography coupled to mass spectrometry to characterize the elastin-derived peptides. Incubation of insoluble human elastin with different elastases revealed that, indeed, each protease degrades elastin in a preferential way giving rise to specific peptide patterns. This opens the possibility of using a given set of peptides as biomarkers for disease-related elastolysis.

Lung inflammation as a therapeutic target in cystic fibrosis

Cystic fibrosis (CF) lung disease is characterized by chronic neutrophilic inflammation and infection. Effective management of airway inflammation could complement other therapies for the treatment of CF. Recent progress has been made in understanding the signaling pathways regulating inflammatory cytokines in the lung. Here we examine the mechanisms responsible for inflammation in the CF lung, and discuss potential therapeutic strategies targeting inflammation.

SSR69071, an elastase inhibitor, reduces myocardial infarct size following ischemia-reperfusion injury

Neutrophil elastase contributes to the severity of cardiac damage following coronary ischemia and reperfusion. We evaluated the effects of 2-(9-(2-piperidinoethoxy)-4-oxo-4H-pyridol[1,2-a]pyrimidin-2-yloxymethyl)-4-(1-methyethyl)-6-methoxy-1,2-benzisothiazol-3(2H)-one-1,1-dioxide hemihydrate (SSR69071), a novel, potent and selective inhibitor of neutrophil elastase, on infarct size in anaesthetized rabbits subjected to coronary artery occlusion for 30 min followed by reperfusion for 120 min. SSR69071 (3 mg/kg i.v.) reduced cardiac infarct size when administered before ischemia (-39%, P<0.05) or just prior to reperfusion (-37%, P<0.05). Subsequent experiments using the latter administration protocol confirmed the ability of SSR69071 (1 and 3 mg/kg i.v.) to reduce infarct size. This cardioprotective activity was associated with inhibition of cardiac elastase.