Distinct effects of tissue-type plasminogen activator and SMTP-7 on cerebrovascular inflammation following thrombolytic reperfusion

SMTP-44D Inhibits Atherosclerotic Plaque Formation in Apolipoprotein-E Null Mice Partly by Suppressing the AGEs-RAGE Axis

SMTP-44D has been reported to have anti-oxidative and anti-inflammatory reactions, including reduced expression of receptor for advanced glycation end products (RAGE) in experimental diabetic neuropathy. Although activation of RAGE with its ligands, and advanced glycation end products (AGEs), play a crucial role in atherosclerotic cardiovascular disease, a leading cause of death in diabetic patients, it remains unclear whether SMTP-44D could inhibit experimental atherosclerosis by suppressing the AGEs–RAGE axis. In this study, we investigated the effects of SMTP-44D on atherosclerotic plaque formation and expression of AGEs in apolipoprotein-E null (Apoe−/−) mice. We further studied here whether and how SMTP-44D inhibited foam cell formation of macrophages isolated from Apoe−/− mice ex vivo. Although administration of SMTP-44D to Apoe−/− mice did not affect clinical or biochemical parameters, it significantly decreased the surface area of atherosclerotic lesions and reduced the atheromatous plaque size, macrophage infiltration, and AGEs accumulation in the aortic roots. SMTP-44D bound to immobilized RAGE and subsequently attenuated the interaction of AGEs with RAGE in vitro. Furthermore, foam cell formation evaluated by Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and gene expression of RAGE, cyclin-dependent kinase 5 (Cdk5) and CD36 in macrophages isolated from SMTP-44D-treated Apoe−/− mice were significantly decreased compared with those from saline-treated mice. Gene expression levels of RAGE and Cdk5 were highly correlated with each other, the latter of which was also positively associated with that of CD36. The present study suggests that SMTP-44D may inhibit atherosclerotic plaque formation in Apoe−/− mice partly by blocking the AGEs-RAGE-induced ox-LDL uptake into macrophages via the suppression of Cdk5-CD36 pathway.

Natural sesquiterpene quinone/quinols: chemistry, biological activity, and synthesis

Covering: 2010 to 2021Sesquiterpene quinone/quinols (SQs) are characterized by a C15-sesquiterpenoid unit incorporating a C6-benzoquinone/quinol moiety. Numerous unprecedented carbon skeletons have been constructed with various connection patterns between the two parts. The potent anti-cancer, anti-inflammatory, anti-microbial, anti-viral, and fibrinolytic activities of SQs are associated with their diverse structures. The representative avarol has even entered the stage of clinical phase II research as an anti-HIV agent, and was developed as paramedic medicine against psoriasis. This review provides an overall summary of 558 new natural SQs discovered between 2010 and 2021, including seven groups and sixteen structure-type subgroups, which comprehensively recapitulates their chemical structures, spectral characteristics, source organisms, biological activities, synthesis, and biosynthesis, aiming to expand the application scope of this unique natural product resource.

A first-in-human study of the anti-inflammatory profibrinolytic TMS-007, an SMTP family triprenyl phenol

AIMS

TMS-007, an SMTP family member, modulates plasminogen conformation and enhances plasminogen-fibrin binding, leading to promotion of endogenous fibrinolysis. Its anti-inflammatory action, mediated by soluble epoxide hydrolase inhibition, may contribute to its efficacy. Evidence suggests that TMS-007 can effectively treat experimental thrombotic and embolic strokes with a wide time window, while reducing haemorrhagic transformation. We aim to evaluate the safety, pharmacokinetics and pharmacodynamics of TMS-007 in healthy volunteers.

METHODS

This was a randomized, placebo-controlled, double blind, dose-escalation study, administered as a single intravenous infusion of TMS-007 in cohorts of healthy male Japanese subjects. Six cohorts were planned, but only five were completed. In each cohort (n = 8), individuals were randomized to receive one of five doses of TMS-007 (3, 15, 60, 180 or 360 mg; n = 6) or placebo (n = 2).

RESULTS

TMS-007 was generally well tolerated, and no serious adverse events were attributed to the drug. A linear dose-dependency was observed for plasma TMS-007 levels. No symptoms of bleeding were observed on brain MRI analysis, and no bleeding-related responses were found on laboratory testing. The plasma levels of the coagulation factor fibrinogen and the anti-fibrinolysis factor α₂ -antiplasmin levels were unchanged after TMS-007 dosing. A slight increase in the plasma level of plasmin-α₂ -antiplasmin complex, an index of plasmin formation, was observed in the TMS-007 group in cohort 2.

CONCLUSIONS

TMS-007 is generally well tolerated and exhibits favourable pharmacokinetic profiles that warrant further clinical development.

Amine-Regulated pri-SMTP Oxidation in SMTP Biosynthesis in Stachybotrys: Possible Implication in Nitrogen Acquisition

SMTP (the name SMTP is derived from Stachybotrys microspora triprenyl phenol) is a family of triprenyl phenol secondary metabolites from a black mold, Stachybotrys microspora. Some SMTP congeners exhibit anti-inflammatory and profibrinolytic activities that, in combination, contribute to the treatment of ischemic stroke. The final step in the SMTP biosynthesis is a non-enzymatic amine conjugation with an o-phthalaldehyde moiety of the precursor pre-SMTP, which can form adducts with proteins and nucleic acids. Thus, pre-SMTP formation should be a precisely regulated, rate-limiting step in the SMTP biosynthesis. To address the mechanism backing this regulation, we purified a metabolite that rapidly disappeared following amine feeding, identifying a novel compound, pri-SMTP. Furthermore, an enzyme, designated as pri-SMTP oxidase, responsible for pri-SMTP conversion to pre-SMTP, was purified. The formation of pri-SMTP, which is regulated by nitrogen and carbon nutrients, occurred in particular septate mycelia. Although pri-SMTP oxidase was expressed constitutively, the consumption of pri-SMTP was accelerated only when a primary amine was fed. Thus, SMTP biosynthesis is regulated by at least three mechanisms: (i) pri-SMTP formation affected by nutrients, (ii) the compartmentalization of pri-SMTP formation/storage, and (iii) amine-regulated pri-SMTP oxidation. Amine-regulated SMTP formation (i.e., amine-capturing with pre-SMTP) may play a role in the nitrogen acquisition/assimilation strategy in S. microspora, since pri-SMTP synthesis occurs on non-preferred nitrogen.

Prognostic values of serum alkaline phosphatase and globulin levels in patients undergoing intravenous thrombolysis

Background

In previous studies, alkaline phosphatase (ALP) level was a prognostic factor for patients with ischemic stroke, and globulin level was associated with hemorrhagic transformation (HT) after intravenous thrombolysis (IVT). However, the association between these serum biomarkers and prognosis in patients with acute ischemic stroke (AIS) who undergo IVT remains unclear. This study aimed to investigate the characteristics of serum ALP and globulin levels after IVT and to assess the relationship between these serum biomarkers and prognosis.

Materials and methods

This retrospective study used a prospectively collected database. We included patients with AIS who received recombinant tissue plasminogen activator (rt-PA) IVT. Demographic information, vascular risk factors, laboratory test results, and other stroke-related data were collected for analysis. Clinical outcomes included HT and 3-month poor outcome (modified Rankin Scale scores ≥ 2) after IVT. The association of ALP and globulin levels with HT and poor outcome was investigated using multivariate logistic regression analysis. An individualized prediction model based on ALP and globulin levels for functional outcomes was established.

Results

We enrolled 750 patients in this study; 452 patients (60.3%) had poor outcome, and 117 patients (15.6%) had HT after IVT. After adjusting for all confounders, serum globulin level [OR = 1.055; 95% confidence intervals (CI): 1.006–1.107; P = 0.028] was independently associated with HT in patients with IVT. Serum ALP (OR = 1.009; 95% CI: 1.002–1.016; P = 0.010) and globulin levels (OR = 1.062; 95% CI: 1.020–1.107; P = 0.004) were associated with 3-month poor outcome in these patients. The constructed individualized prediction model for the 3-month poor outcome comprised the National Institutes of Health Stroke Scale (NIHSS) score, Trial of Org 10172 in Acute Stroke Treatment (TOAST), history of antihypertensive therapy, ALP and globulin levels. The area under the curve of the training and validation sets were 0.726 and 0.706, respectively, revealing that the model had good discriminating power. The P-values for the Hosmer-Lemeshow test in the training and validation sets were 0.978 and 0.148, respectively, indicating the model had good calibration.

Conclusion

This study found that higher serum globulin levels were independently associated with HT. Additionally, higher serum ALP and globulin levels were independently associated with a poor outcome in patients after IVT.

Progress in Isoindolone Alkaloid Derivatives from Marine Microorganism: Pharmacology, Preparation, and Mechanism

Compound 1 (SMTP-7, also FGFC1), an isoindolone alkaloid from marine fungi Starchbotrys longispora FG216 and fungi Stachybotrys microspora IFO 30018, possessed diverse bioactivities such as thrombolysis, anti-inflammatory and anti-oxidative properties, and so on. It may be widely used for the treatment of various diseases, including cerebral infarction, stroke, ischemia/reperfusion damage, acute kidney injury, etc. Especially in cerebral infarction, compound 1 could reduce hemorrhagic transformation along with thrombolytic therapy, as the traditional therapies are accompanied with bleeding risks. In the latest studies, compound 1 selectively inhibited the growth of NSCLC cells with EGFR mutation, thus demonstrating its excellent anti-cancer activity. Herein, we summarized pharmacological activities, preparation of staplabin congeners—especially compound 1—and the mechanism of compound 1, with potential therapeutic applications.

FGFC1 Exhibits Anti-Cancer Activity via Inhibiting NF-κB Signaling Pathway in EGFR-Mutant NSCLC Cells

FGFC1, an active compound isolated from the culture of marine fungi Stachybotrys longispora FG216, elicits fibrinolytic, anti-oxidative, and anti-inflammatory activity. We have previously reported that FGFC1 inhibited the proliferation, migration, and invasion of the non-small cell lung cancer (NSCLC) cells in vitro. However, the precise mechanisms of FGFC1 on NSCLC and its anti-cancer activity in vivo remains unclear. Hence, this study was focused to investigate the effects and regulatory mechanisms of FGFC1 on two NSCLC cell lines, EGFR-mutant PC9 (ex19del) and EGFR wild-type H1299. Results suggested that FGFC1 significantly inhibited proliferation, colony formation, as well as triggered G0/G1 arrest and apoptosis of PC9 cells in a dose- and time-dependent manner, but no obvious inhibitory effects were observed in H1299 cells. Subsequently, transcriptome analysis revealed that FGFC1 significantly down-regulated 28 genes related to the NF-κB pathway, including IL-6, TNF-α, and ICAM-1 in the PC9 cells. We further confirmed that FGFC1 decreased the expression of protein p-IKKα/β, p-p65, p-IκB, IL-6, and TNF-α. Moreover, NF-κB inhibitor PDTC could strengthen the effects of FGFC1 on the expression of CDK4, Cyclin D1, cleaved-PARP-1, and cleaved-caspase-3 proteins, suggesting that the NF-κB pathway plays a major role in FGFC1-induced cell cycle arrest and apoptosis. Correspondingly, the nuclear translocation of p-p65 was also suppressed by FGFC1 in PC9 cells. Finally, the intraperitoneal injection of FGFC1 remarkably inhibited PC9 xenograft growth and decreased the expression of Ki-67, p-p65, IL-6, and TNF-α in tumors. Our results indicated that FGFC1 exerted anti-cancer activity in PC9 cells via inhibiting the NF-κB signaling pathway, providing a possibility for FGFC1 to be used as a lead compound for the treatment of NSCLC in the future.

Potent efficacy of Stachybotrys microspora triprenyl phenol-7, a small molecule having anti-inflammatory and antioxidant activities, in a mouse model of acute kidney injury

Acute kidney injury (AKI) increases the risk of chronic kidney disease (CKD), complicates existing CKD, and can lead to the end-stage renal disease. However, there are no approved effective therapeutics for AKI. Recent studies have suggested that inflammation and oxidative stress are the primary causes of AKI. We previously reported the potential anti-inflammatory and antioxidant activities of Stachybotrys microspora triprenyl phenol-7 (SMTP-7). The aim of the present study was to evaluate the efficacy of SMTP-7 in AKI model mice. AKI was induced in mice by ischemia of the left renal artery and vein for 45 min followed by reperfusion, 2 weeks after the removal of right kidney. The efficacy of SMTP-7 was determined by measuring the renal function using urine and serum samples and morphological assessment. For deciphering the mechanism of action of SMTP-7, inflammatory cytokines and oxidative stress in kidney were detected. SMTP-7 (0.01, 0.1, 1, 10 mg/kg) dose-dependently improved the renal function. In addition, it improved the damage to renal tubules and exhibited anti-inflammatory and antioxidant activities in the kidney of AKI mice. These results indicate the potential of SMTP-7 as a medicinal compound for the treatment of AKI.

Modulation of vascular integrity and neuroinflammation by peroxiredoxin 4 following cerebral ischemia-reperfusion injury

Ischemic stroke is a leading cause of morbidity and mortality worldwide, with oxidative stress playing a key role in the injury mechanism of thrombolytic therapy. There is increasing evidence that oxidative stress damages endothelial cells (ECs), degrades tight junction proteins (TJs), and contributes to increased blood-brain barrier (BBB) permeability. It has been demonstrated that the breakdown of BBB could increase the risk of intracerebral hemorrhagic transformation in ischemic stroke. And an episode of cerebral ischemia/reperfusion (I/R) also initiates oxidative stress-mediated inflammatory processes in ECs, which further promotes BBB disruption and the progression of brain injury. Previous studies have revealed that antioxidants could inhibit ROS generation and attenuate BBB disruption after cerebral I/R. Peroxiredoxin 4 (Prx4) is a member of the antioxidant enzymes family (Prx1-6) and has been characterized to be an efficient H₂O₂ scavenger. It should be noted that Prx4 may be directly involved in the protection of ECs from the effects of ROS and function in ECs as a membrane-associated peroxidase. This paper reviewed the implication of Prx4 on vascular integrity and neuroinflammation following a cerebral I/R injury.

Impact of SMTP Targeting Plasminogen and Soluble Epoxide Hydrolase on Thrombolysis, Inflammation, and Ischemic Stroke

Stachybotrys microspora triprenyl phenol (SMTP) is a large family of small molecules derived from the fungus S. microspora. SMTP acts as a zymogen modulator (specifically, plasminogen modulator) that alters plasminogen conformation to enhance its binding to fibrin and subsequent fibrinolysis. Certain SMTP congeners exert anti-inflammatory effects by targeting soluble epoxide hydrolase. SMTP congeners with both plasminogen modulation activity and anti-inflammatory activity ameliorate various aspects of ischemic stroke in rodents and primates. A remarkable feature of SMTP efficacy is the suppression of hemorrhagic transformation, which is exacerbated by conventional thrombolytic treatments. No drug with such properties has been developed yet, and SMTP would be the first to promote thrombolysis but suppress disease-associated bleeding. On the basis of these findings, one SMTP congener is under clinical study and development. This review summarizes the discovery, mechanism of action, pharmacological activities, and development of SMTP.

Strategies to prevent hemorrhagic transformation after reperfusion therapies for acute ischemic stroke: A literature review

BACKGROUND

Reperfusion therapies by tissue plasminogen activator (tPA) and mechanical thrombectomy (MT) have ushered in a new era in the treatment of acute ischemic stroke (AIS). However, reperfusion therapy-related HT remains an enigma.

AIM

To provide a comprehensive review focused on emerging concepts of stroke and therapeutic strategies, including the use of protective agents to prevent HT after reperfusion therapies for AIS.

METHODS

A literature review was performed using PubMed and the ClinicalTrials.gov database.

RESULTS

Risk of HT increases with delayed initiation of tPA treatment, higher baseline glucose level, age, stroke severity, episode of transient ischemic attack within 7 days of stroke onset, and hypertension. At a molecular level, HT that develops after thrombolysis is thought to be caused by reactive oxygen species, inflammation, remodeling factor-mediated effects, and tPA toxicity. Modulation of these pathophysiological mechanisms could be a therapeutic strategy to prevent HT after tPA treatment. Clinical mechanisms underlying HT after MT are thought to involve smoking, a low Alberta Stroke Program Early CT Score, use of general anesthesia, unfavorable collaterals, and thromboembolic migration. However, the molecular mechanisms are yet to be fully investigated. Clinical trials with MT and protective agents have also been planned and good outcomes are expected.

CONCLUSION

To fully utilize the easily accessible drug-tPA-and the high recanalization rate of MT, it is important to reduce bleeding complications after recanalization. A future study direction could be to investigate the recovery of neurological function by combining reperfusion therapies with cell therapies and/or use of pleiotropic protective agents.

Thrombolytic Therapy for Acute Ischemic Stroke: Past and Future

BACKGROUND

Thromboembolic ischemic stroke, which is mainly caused by hypertension, as well as plasma dyslipidemia, arterial fibrillation and diabetes, is a leading cause of death in the US and other countries. Numerous clinical trials for thrombolytic drugs, which aimed to pharmacologically dissolve thrombi, were conducted in the 1950s, when the first thrombolytic therapy was performed.

METHODS

In this study, we summarize the pathophysiologic features of ischemic stroke, and the history of thrombolytic therapy, and discuss the recent progress that has been made in the ongoing development of thrombolytic drugs.

CONCLUSION

Thrombolytic therapy is sometimes accompanied by harmful hemorrhagic insults; accordingly, a window of time wherein therapy can safely be performed has been established for this approach. Several basic and clinical studies are ongoing to develop next-generation thrombolytic drugs to expand the time window.

Natural disesquiterpenoids: an update

This review highlights the progress on the isolation, bioactivity, biogenesis and total synthesis of dimeric sesquiterpenoids since 2010.

Efficacy of SMTP-7, a small-molecule anti-inflammatory thrombolytic, in embolic stroke in monkeys

SMTP-7 (Stachybotrys microspora triprenyl phenol-7) is a small molecule that promotes thrombolysis and suppresses inflammation possibly through plasminogen modulation and soluble epoxide hydrolase (sEH) inhibition, respectively. Here, we demonstrate an efficacy of SMTP-7 in a severe embolic stroke model in monkeys. The middle cerebral artery was embolized by an autologous blood clot. Saline, SMTP-7, or tissue-type plasminogen activator (t-PA) (n = 5 in each group) was given after 3 hours, and neurologic deficit scoring and infarct characterization were performed after 24 hours. Hemorrhagic infarct-accompanied premature death was observed for two animals in t-PA group. SMTP-7 treatment significantly reduced the sizes of infarct by 65%, edema by 37%, and clot by 55% compared to saline treatment. Plasma levels of the products of plasminogen activation (plasmin-α2-antiplasmin complex) and sEH reaction (dihydroxyeicosatrienoic acid) in SMTP-7 group were 794% (P < 0.05) and 60% (P = 0.085) compared to saline group, respectively. No significant changes in the plasma levels of MMP-9, CRP, MCP-1, and S100B were found. There was an inverse correlation between plasmin-α2-antiplasmin complex level and infarct volume (r = 0.93, P < 0.05), suggesting a role of thrombolysis in the SMTP-7 action to limit infarct development. In conclusion, SMTP-7 is effective in treating severe embolic stroke in monkeys under conditions where t-PA treatment tends to cause hemorrhagic infarct-associated premature death.

Neuroprotective effects of SMTP-44D in mice stroke model in relation to neurovascular unit and trophic coupling

Stachybotrys microspora triprenyl phenol (SMTP)-44D has both anti-oxidative and anti-inflammatory activities, but its efficacy has not been proved in relation to the pathological changes of neurovascular unit (NVU) and neurovascular trophic coupling (NVTC) in ischemic stroke. Here, the present study was designed to assess the efficacies of SMTP-44D, moreover, compared with the standard neuroprotective reagent edaravone in ischemic brains. ICR mice were subjected to transient middle cerebral artery occlusion (tMCAO) for 60 min, SMTP-44D (10 mg/kg) or edaravone (3 mg/kg) was intravenously administrated through subclavian vein just after the reperfusion, and these mice were examined at 1, 3, and 7 d after reperfusion. Compared with the vehicle group, SMTP-44D treatment revealed obvious ameliorations in clinical scores and infarct volume, meanwhile, markedly suppressed the accumulations of 4-HNE, 8-OHdG, nitrotyrosine, RAGE, TNF-α, Iba-1, and cleaved caspase-3 after tMCAO. In addition, SMTP-44D significantly prevented the dissociation of NVU and improved the intensity of NAGO/BDNF and the number of BDNF/TrkB and BDNF/NeuN double positive cells. These effects of SMTP-44D in reducing oxidative and inflammatory stresses were similar to or stronger than those of edaravone. The present study demonstrated that SMTP-44D showed strong anti-oxidative, anti-inflammatory, and anti-apoptotic effects, moreover, the drug also significantly improved the NVU damage and NVTC in the ischemic brain.

Reduction of Ischemia Reperfusion-Related Brain Hemorrhage by Stachybotrys Microspora Triprenyl Phenol-7 in Mice With Antioxidant Effects

BACKGROUND

Stachybotrys microspora triprenyl phenol-7 (SMTP-7) has both thrombolytic and anti-inflammatory effects, but its neuroprotective effects on cerebral ischemia are still unclear. The present study assessed the antioxidative and neurovascular unit (NVU) protective effects of SMTP-7 using transient middle cerebral artery occlusion (tMCAO) mice.

METHODS

After 60 minutes tMCAO, 0.9% NaCl, tissue-type plasminogen activator (tPA), SMTP-7 or tPA + SMTP-7 was intravenously administrated through subclavian vein just before the reperfusion, and these mice were examined at 24 hours after reperfusion. We histologically assessed the hemorrhage and expressive changes of antioxidative markers in brains.

RESULTS

SMTP-7 treatment showed a similar antithrombotic effect to tPA, but significantly decreased the hemorrhage volumes and the number of 4-HNE, 3-NT and 8-OHdG positive cells, meanwhile, ameliorated the decrease of collagen IV in the ischemic brains. However, tPA + SMTP-7 treatment did not decrease hemorrhage volumes nor showed NVU protective effect.

CONCLUSIONS

The present study suggested that SMTP-7 provided therapeutic benefits for ischemic stroke through antioxidative and NVU protective effects unlike tPA alone or tPA + SMTP-7.

Antineuroinflammatory Effect of SMTP-7 in Ischemic Mice

BACKGROUND

Stachybotrys microspora triprenyl phenol-7 (SMTP-7) has both potentials of thrombolytic and neuroprotective effects, but its detailed neuroprotective mechanisms in ischemic stroke are still unclear. Here, we assessed the neuroprotective effects of SMTP-7 for anti-inflammatory and antiapoptosis mechanisms after 60 minutes of transient middle cerebral artery occlusion (tMCAO) in mice.

METHODS

After 60minutes of tMCAO, 0.9% NaCl, tissue-type plasminogen activator (tPA), SMTP-7 or tPA+SMTP-7 was intravenously administrated through subclavian vein just before the reperfusion, and these mice were examined at 24hours after reperfusion. We histologically assessed the antineuroinflammatory effect of SMTP-7 on the expressive changes of inflammatory markers in ischemic mouse brains.

RESULTS

Compared with the vehicle and tPA groups, SMTP-7 treatment significantly improved clinical scores and decreased the infarct volume and the numbers of TNF-α, nuclear factor-κB (NF-κB), nucleotide oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3), and cleaved caspase-3-positive cells in the brain of mice at 24hours after tMCAO but not p62-positive cells. However, tPA+SMTP-7 treatment did not show such effects.

CONCLUSIONS

The present study suggested that SMTP-7 provides a therapeutic benefit for ischemic stroke mice through anti-inflammatory and antiapoptotic effects but not antiautophagic effect.

Small Molecules: Therapeutic Application in Neuropsychiatric and Neurodegenerative Disorders

In recent years, an increasing number of studies have been published, focusing on the potential therapeutic use of small catalytic agents with strong biological properties. So far, most of these works have only regarded specific clinical fields, such as oncology, infectivology and general pathology, in particular with respect to the treatment of significant inflammatory processes. However, interesting data on possible therapeutic applications of small molecules for the treatment of neuropsychiatric and neurodegenerative illnesses are emerging, especially with respect to the possibility to modulate the cellular redox state. Indeed, a crucial role of redox dysregulation in the pathogenesis of these disorders has been widely demonstrated by both pre-clinical and clinical studies, being the reduction of the total amount of free radicals a promising novel therapeutic approach for these diseases. In this review, we focused our interest on studies published during the last ten years reporting therapeutic potential of small molecules for the treatment of neuropsychiatric and neurodegenerative disorders, also based on the biological efficiency of these compounds in detecting intracellular disturbances induced by increased production of reactive oxygen species.

Evaluation of the effects of a new series of SMTPs in the acetic acid-induced embolic cerebral infarct mouse model

We reported previously that Stachybotrys microspora triprenyl phenol-7 (SMTP-7) showed potential thrombolytic, anti-inflammatory and anti-oxidant effects that account for its excellent pharmacological activity such as having a wider therapeutic time window than tissue plasminogen activator (t-PA) and a significant protection against hemorrhage. The aim of the present study was to evaluate and compare the effect of a new series of SMTPs in the acetic acid-induced embolic cerebral infarct mouse model. Thrombotic occlusion was produced in mice by inducing the transfer of acetic acid-induced thrombi from the right common carotid artery into the brain. SMTPs were evaluated by their effect on reducing infarct area, neurological score and edema. Furthermore, plasmin formation, anti-inflammatory and anti-oxidant activities were assessed by fibrin zymography, measuring pro-inflammatory gene expression, and thiobarbituric acid reactive substances (TBARS) assay, respectively. Treatment with either SMTP-22 or SMTP-43 (10mg/kg), which have similar plasmin formation, anti-inflammatory and anti-oxidant activities to SMTP-7, resulted in reduced infarct area, neurological score and edema. Coexistence of all these three activities appears to be important for the treatment of embolic infarction because SMTP-6, SMTP-25, and SMTP-44D (10mg/kg), which are each missing at least one of the three functions, were not as effective. Therefore, these results indicate that SMTP-22 and SMTP-43 have potential as medicinal compounds for the treatment of embolic cerebral infarction.

Therapeutic Strategies to Attenuate Hemorrhagic Transformation After Tissue Plasminogen Activator Treatment for Acute Ischemic Stroke

This review focuses on the mechanisms and emerging concepts of stroke and therapeutic strategies for attenuating hemorrhagic transformation (HT) after tissue plasminogen activator (tPA) treatment for acute ischemic stroke (AIS). The therapeutic time window for tPA treatment has been extended. However, the patients who are eligible for tPA treatment are still ＜5% of all patients with AIS. The risk of serious or fatal symptomatic hemorrhage increases with delayed initiation of treatment. HT is thought to be caused by 1) ischemia/reperfusion injury; 2) the toxicity of tPA itself; 3) inflammation; and/or 4) remodeling factor-mediated effects. Modulation of these pathophysiologies is the basis of direct therapeutic strategies to attenuate HT after tPA treatment. Several studies have revealed that matrix metalloproteinases and free radicals are potential therapeutic targets. In addition, we have demonstrated that the inhibition of the vascular endothelial growth factor-signaling pathway and supplemental treatment with a recombinant angiopoietin-1 protein might be a promising therapeutic strategy for attenuating HT after tPA treatment through vascular protection. Moreover, single-target therapies could be insufficient for attenuating HT after tPA treatment and improving the therapeutic outcome of patients with AIS. We recently identified progranulin, which is a growth factor and a novel target molecule with multiple therapeutic effects. Progranulin might be a therapeutic target that protects the brain through suppression of vascular remodeling (vascular protection), neuroinflammation, and/or neuronal death (neuroprotection). Clinical trials which evaluate the effects of anti-VEGF drugs or PGRN-based treatment with tPA will be might worthwhile.

Edaravone-Encapsulated Agonistic Micelles Rescue Ischemic Brain Tissue by Tuning Blood-Brain Barrier Permeability

Thrombolysis has been a standard treatment for ischemic stroke. However, only 2-7% patients benefit from it because the thrombolytic agent has to be injected within 4.5 h after the onset of symptoms to avoid the increasing risk of intracerebral hemorrhage. As the only clinically approved neuroprotective drug, edaravone (EDV) rescues ischemic brain tissues by eradicating over-produced reactive oxygen species (ROS) without the limitation of therapeutic time-window. However, EDV's short circulation half-life and inadequate cerebral uptake attenuate its therapeutic efficacy. Here we developed an EDV-encapsulated agonistic micelle (EDV-AM) to specifically deliver EDV into brain ischemia by actively tuning blood-brain barrier (BBB) permeability. The EDV-AM actively up-regulated endothelial monolayer permeability in vitro. HPLC studies showed that EDV-AM delivered more EDV into brain ischemia than free EDV after intravenous injection. Magnetic resonance imaging also demonstrated that EDV-AM more rapidly salvaged ischemic tissue than free EDV. Diffusion tensor imaging indicated the highest efficiency of EDV-AM in accelerating axonal remodeling in the ipsilesional white matter and improving functional behaviors of ischemic stroke models. The agonistic micelle holds promise to improve the therapeutic efficiency of ischemic stroke patients who miss the thrombolytic treatment.

Effects of Early Post-Ischemic Reperfusion and tPA on Cerebrovascular Function and Nitrosative Stress in Female Rats

Stroke is a major health issue in women. Our previous studies in male rats showed decreased myogenic tone in middle cerebral arteries (MCAs) after ischemia and reperfusion (I/R), while tone in parenchymal arterioles (PAs) was increased. This vascular response may aggravate stroke damage in males by limiting reperfusion; however, the effect in females is not known. The current study investigated the effect of I/R and tissue plasminogen activator (tPA) on myogenic tone and reactivity of MCAs and PAs in female rats. Nitrosative stress by peroxynitrite and recruitment of inflammatory neutrophils to the microvasculature were also studied. Female rats were subjected to 2-h MCA filament occlusion (n = 16) or sham surgery (n = 17) and given tPA (1 mg/kg, i.v) or vehicle followed by 30-min reperfusion. Myogenic tone and reactivity were measured in isolated and pressurized MCAs and PAs from the same animals. Cerebrovascular F-actin, 3-nitrotyrosine (3-NT, peroxynitrite marker), and intravascular neutrophils were quantified. Myogenic tone and constriction to the nitric oxide synthase inhibitor Nω-nitro-L-arginine were decreased in MCAs but unchanged in PAs after I/R with no effect of tPA. F-actin and 3-NT expression were unaffected by I/R or tPA. Our study showed that MCAs from females, similar to what has been seen in males, are dilated after I/R and have decreased myogenic tone while tone in PAs was unchanged. Increased small vessel resistance may contribute to decreased reperfusion and worse outcome after stroke.

Systematic review of survival time in experimental mouse stroke with impact on reliability of infarct estimation

BACKGROUND

Stroke is the second most common cause of death worldwide. Only one treatment for acute ischemic stroke is currently available, thrombolysis with rt-PA, but it is limited in its use. Many efforts have been invested in order to find additive treatments, without success. A multitude of reasons for the translational problems from mouse experimental stroke to clinical trials probably exists, including infarct size estimations around the peak time of edema formation. Furthermore, edema is a more prominent feature of stroke in mice than in humans, because of the tendency to produce larger infarcts with more substantial edema.

PURPOSE

This paper will give an overview of previous studies of experimental mouse stroke, and correlate survival time to peak time of edema formation. Furthermore, investigations of whether the included studies corrected the infarct measurements for edema and a comparison of correction methods will be discussed.

METHOD

Relevant terms were searched in the National Library of Medicine PubMed database. A method for classification of infarct measurement methods was made using a naming convention.

CONCLUSION

Our study shows that infarct size estimations are often performed around the peak time of edema, with a median of 24h. Most studies do consider edema formation, however, there is no consensus on what method to use to correct for edema. Furthermore, investigations into neuroprotective drugs should use longer survival times to ensure completion of the investigated process. Our findings indicate a need for more research in this area, and establishment of common correction methodology.

Method parameters' impact on mortality and variability in mouse stroke experiments: a meta-analysis

Although hundreds of promising substances have been tested in clinical trials, thrombolysis currently remains the only specific pharmacological treatment for ischemic stroke. Poor quality, e.g. low statistical power, in the preclinical studies has been suggested to play an important role in these failures. Therefore, it would be attractive to use animal models optimized to minimize unnecessary mortality and outcome variability, or at least to be able to power studies more exactly by predicting variability and mortality given a certain experimental setup. The possible combinations of methodological parameters are innumerous, and an experimental comparison of them all is therefore not feasible. As an alternative approach, we extracted data from 334 experimental mouse stroke articles and, using a hypothesis-driven meta-analysis, investigated the method parameters’ impact on infarct size variability and mortality. The use of Swiss and C57BL6 mice as well as permanent occlusion of the middle cerebral artery rendered the lowest variability of the infarct size while the emboli methods increased variability. The use of Swiss mice increased mortality. Our study offers guidance for researchers striving to optimize mouse stroke models.

Isoprene Side-chain of SMTP is Essential for Soluble Epoxide Hydrolase Inhibition and Cellular Localization

SMTPs, a family of natural small molecules that effectively treat ischemic stroke, are subject to clinical development. SMTPs enhance plasminogen activation and inhibit soluble epoxide hydrolase (sEH), leading to promotion of endogenous thrombolysis and anti-inflammation. The SMTP molecule consists of a tricyclic γ-lactam moiety, an isoprene side-chain, and an N-linked side-chain. Here, we investigate the yet-to-be-characterized function of the isoprene side-chain of SMTPs in sEH inhibition and cellular distribution. The results demonstrated that oxidative modification as well as truncation of the side-chain abolished epoxide hydrolase inhibition. The introduction of a terminal hydroxy group exceptionally unaffected epoxide hydrolase, but led to impaired cellular localization, resulting in diminution of cellular epoxide hydrolase inhibition. Thus, the isoprene side-chain of SMTP is an important pharmacophore for epoxide hydrolase inhibition and cellular localization.

Mechanism of the action of SMTP-7, a novel small-molecule modulator of plasminogen activation

SMTP-7 is a small molecule that promotes the proteolytic activation of plasminogen by relaxing its conformation. SMTP-7 has excellent therapeutic activities against thrombotic stroke in several rodent models. The objective of this study was to elucidate detailed mechanism of the action of SMTP-7 in vitro. We report here that the action of SMTP-7 requires a cofactor with a long-chain alkyl or alkenyl group, and that the fifth kringle domain (kringle 5) of plasminogen is involved in the SMTP-7 action. In this study, we found that the SMTP-7 action to enhance plasminogen activation depended on the presence of a certain type of surfactant, and we screened biologically relevant molecules for their cofactor activity for the SMTP action. As a result, phospholipids, sphingolipids, and oleic acid were found to be active in assisting the SMTP-7 action. On the contrary, stearic acid and bile acids were inactive. Thus, a certain structural element, not only the surface-activating potential, is required for a compound to act as a cofactor for the SMTP-7 action. The plasminogen molecule consists of a PAN domain, five kringle domains, and a serine protease domain. The cofactor-dependent effects of SMTP-7 was observed with plasminogen species including kringle 5 such as intact plasminogen (Glu-plasminogen), des-PAN plasminogen (Lys-plasminogen), and des-[PAN - (kringles 1-4)] plasminogen (mini-plasminogen). However, SMTP-7 effect was not observed with the smallest plasminogen species des-[PAN - (kringles 1-4) and a half of kringle 5)] plasminogen (micro-plasminogen). Thus, kringle 5 is crucial for the action of SMTP-7.

Structure-activity relationships of the plasminogen modulator SMTP with respect to the inhibition of soluble epoxide hydrolase

A family of fungal metabolites, SMTP, is a small-molecule plasminogen modulator that enhances plasminogen activation, leading to thrombolysis. We recently demonstrated that SMTP-7 effectively treats ischemic stroke due to its thrombolytic activity as well as anti-inflammatory action, which is attributable to soluble epoxide hydrolase (sEH) inhibition. In this paper, we studied detailed structure-activity relationships of plasminogen modulation and sEH inhibition using 25 SMTP congeners including six newly synthesized ones. The results clearly demonstrate that the structure of the N-linked side chain of SMTP congeners markedly affect their activities toward plasminogen modulation and inhibitions of the two activities of sEH (C-terminal epoxide hydrolase and N-terminal phosphatase). A slight change in the N-linked side chain results in affording selectivity of SMTP congeners. Many congeners, which lacked plasminogen modulation activity, differently inhibited the two sEH activities depending on the structures of the N-linked side chain. Some congeners were active in plasminogen modulation and inhibition of both activities of sEH. These results help comprehensive understanding of ideal design of a drug useful for ischemic diseases that are associated with inflammation, such as stroke.

Methylophiopogonanone A Protects against Cerebral Ischemia/Reperfusion Injury and Attenuates Blood-Brain Barrier Disruption In Vitro

Methylophiopogonanone A (MO-A), an active homoisoflavonoid of the Chinese herb Ophiopogon japonicus which has been shown to have protective effects on cerebral ischemia/reperfusion (I/R) injury, has been demonstrated to have anti-inflammatory and anti-oxidative properties. However, little is known about its role in cerebral I/R injury. Therefore, in this study, by using a middle cerebral artery occlusion (MCAO) and reperfusion rat model, the effect of MO-A on cerebral I/R injury was examined. The results showed that MO-A treatment reduced infarct volume and brain edema, improved neurological deficit scores, reversed animal body weight decreases, and increased animal survival time in the stroke groups. Western blotting showed that MO-A suppressed MMP-9, but restored the expression of claudin-3 and claudin-5. Furthermore, transmission electron microscopy were monitored to determine the blood-brain barrier (BBB) alterations in vitro. The results showed that MO-A markedly attenuated BBB damage in vitro. Additionally, MO-A inhibited ROS production in ECs and MMP-9 release in differentiated THP-1 cells in vitro, and suppressed ICAM-1 and VCAM-1 expression in ECs and leukocyte/EC adhesion. In conclusion, our data indicate that MO-A has therapeutic potential against cerebral I/R injury through its ability to attenuate BBB disruption by regulating the expression of MMP-9 and tight junction proteins.

Fungal natural products in research and development

To date approximately 100 000 fungal species are known although far more than one million are expected. The variety of species and the diversity of their habitats, some of them less exploited, allow the conclusion that fungi continue to be a rich source of new metabolites. Besides the conventional fungal isolates, an increasing interest in endophytic and in marine-derived fungi has been noticed. In addition new screening strategies based on innovative chemical, biological, and genetic approaches have led to novel fungal metabolites in recent years. The present review focuses on new fungal natural products published from 2009 to 2013 highlighting the originality of the structures and their biological potential. Furthermore synthetic products based on fungal metabolites as well as new developments in the uses or the biological activity of known compounds or new derivatives are discussed.

Soluble epoxide hydrolase as an anti-inflammatory target of the thrombolytic stroke drug SMTP-7

Although ischemic stroke is a major cause of death and disability worldwide, only a small fraction of patients benefit from the current thrombolytic therapy due to a risk of cerebral hemorrhage caused by inflammation. Thus, the development of a new strategy to combat inflammation during thrombolysis is an urgent demand. The small molecule thrombolytic SMTP-7 effectively treats ischemic stroke in several animal models with reducing cerebral hemorrhage. Here we revealed that SMTP-7 targeted soluble epoxide hydrolase (sEH) to suppress inflammation. SMTP-7 inhibited both of the two sEH enzyme activities: epoxide hydrolase (which inactivates anti-inflammatory epoxy-fatty acids) and lipid phosphate phosphatase. SMTP-7 suppressed epoxy-fatty acid hydrolysis in HepG2 cells in culture, implicating the sEH inhibition in the anti-inflammatory mechanism. The sEH inhibition by SMTP-7 was independent of its thrombolytic activity. The simultaneous targeting of thrombolysis and sEH by a single molecule is a promising strategy to revolutionize the current stroke therapy.

Atorvastatin protects against cerebral ischemia/reperfusion injury through anti-inflammatory and antioxidant effects

In addition to its lipid-lowering effect, atorvastatin exerts anti-inflammatory and antioxidant effects as well. In this study, we hypothesized that atorvastatin could protect against cerebral ischemia/reperfusion injury. The middle cerebral artery ischemia/reperfusion model was established, and atorvastatin, 6.5 mg/kg, was administered by gavage. We found that, after cerebral ischemia/reperfusion injury, levels of the inflammation-related factors E-selectin and myeloperoxidase were upregulated, the oxidative stress-related marker malondialdehyde was increased, and superoxide dismutase activity was decreased in the ischemic cerebral cortex. Atorvastatin pretreatment significantly inhibited these changes. Our findings indicate that atorvastatin protects against cerebral ischemia/reperfusion injury through anti-inflammatory and antioxidant effects.

SMTP-7, a new thrombolytic agent, decreases hemorrhagic transformation after transient middle cerebral artery occlusion under warfarin anticoagulation in mice

Stachybotrys microspora triprenyl phenol-7 (SMTP-7) is a new thrombolytic agent that exhibits anti-inflammatory effects. We previously demonstrated that the hemorrhagic transformation was fewer with SMTP-7 than with recombinant tissue plasminogen activator (rt-PA) following ischemia-reperfusion in animal models. We hypothesized that SMTP-7 may decrease hemorrhagic transformation after ischemia-reperfusion under the warfarin-treated condition. Transient middle cerebral artery occlusion (MCAO) was induced for 3h using an intraluminal suture in warfarin-treated mice to produce hemorrhagic transformation. Warfarin was administered orally for a 24-h feeding period before MCAO through bottled drinking water (5mg in 375 ml tap water), resulting in a mean INR of 5.6±0.2. Mice were treated with vehicle, rt-PA, or SMTP-7 5h before reperfusion. Twenty percent of vehicle-treated and 50.0% of rt-PA-treated mice died 24h after reperfusion, while all SMTP-7-treated mice survived. Hemorrhagic severity in SMTP-7-treated mice was significantly lower than that in rt-PA-treated mice. Neurological deficit was significantly lower in SMTP-7-treated mice than vehicle- and rt-PA-treated mice. These results indicate that SMTP-7 decreases mortality, hemorrhagic transformation, and neurological deficits, and can be a safe thrombolytic agent following MCAO under the warfarin-treated condition.

Altered gene expression in an embolic stroke model after thrombolysis with tissue plasminogen activator and Stachybotrys microspora triprenyl phenol-7

The present study compares gene expression and infarct area in a mouse model of embolic stroke after thrombolysis with t-PA and SMTP-7. Embolic occlusion was induced by transfer of acetic acid-induced embolus into the brain. t-PA or SMTP-7 was administered 3 h after embolization. Changes in gene expression were evaluated using microarray and RT-PCR analysis. To determine the involvement of reactive oxygen species in the response to t-PA, the free radical scavenger edaravone was infused immediately before t-PA administration. The expressions of 459 genes involved in the inflammatory response, cell-to-cell signaling, cell movement, and inflammatory disease were altered by embolic occlusion. Twenty-two of those genes were upregulated after t-PA but not SMTP-7 administration. Differences between the t-PA- and SMTP-7-treated groups in the expression of genes including the proinflammatory genes Il6, Stat3, S100a8, and Mmp9 were confirmed with RT-PCR. Edaravone ameliorated the overexpression of these genes. Our data demonstrate differences in gene expression following treatment with SMTP-7 or t-PA that likely explain the difference in therapeutic time windows of the two drugs. ROS are involved in the overexpression of proinflammatory genes. The wide therapeutic time window may be achieved through an anti-oxidative effect and inhibition of proinflammatory gene overexpression.

Recombinant tissue plasminogen activator enhances microglial cell recruitment after stroke in mice

The effect of recombinant human tissue plasminogen activator (rtPA) on neuroinflammation after stroke remains largely unknown. Here, we tested the effect of rtPA on expression of cellular adhesion molecules, chemokines, and cytokines, and compared those with levels of inflammatory cell recruitment, brain injury, and mortality over 3 days after transient middle cerebral artery occlusion (MCAO) in mice. Mortality was dramatically increased after rtPA treatment compared with saline treatment during the first day of reperfusion. Among the animals that survived, rtPA significantly increased CCL3 expression, microglia recruitment, and cerebral infarction 6 hours after MCAO. In contrast, the extent of neutrophils and macrophages infiltration in the brain was similar in both saline- and rtPA-treated animals. Recombinant human tissue plasminogen activator induced Il1b and Tnf expression, 6 and 72 hours after MCAO, respectively, and dramatically reduced interleukin 6 (IL-6) level 24 hours after reperfusion. A dose response study confirmed the effect of rtPA on CCL3 and Il1b expressions. The effect was similar at the doses of 1 and 10 mg/kg. In conclusion, we report for the first time that rtPA amplified microglia recruitment early after stroke in association with a rapid CCL3 production. This early response may take part in the higher susceptibility of rtPA-treated animals to reperfusion injury.

SMTP-7, a novel small-molecule thrombolytic for ischemic stroke: a study in rodents and primates

SMTP-7 (Stachybotrys microspora triprenyl phenol-7), a small molecule that promotes plasminogen activation through the modulation of plasminogen conformation, has excellent therapeutic activity against cerebral infarction in several rodent models. Detailed evaluations of SMTP-7 in a primate stroke model are needed for effective, safe drug development. Here we evaluated SMTP-7 in a monkey photochemical-induced thrombotic middle cerebral artery (MCA) occlusion model (n=6), in which MCA occlusion was followed by recanalization/reocclusion. SMTP-7 (10 mg/kg, intravenous infusion) significantly increased the postinfusion MCA recanalization rate (32.5-fold, P=0.043) and ameliorated the post-24-h neurologic deficit (by 29%, P=0.02), cerebral infarct (by 46%, P=0.033), and cerebral hemorrhage (by 51%, P=0.013) compared with the vehicle control animals. In normal monkeys, SMTP-7 did not affect general physiologic or hemostatic variables, including coagulation and platelet parameters. Investigations in rodent models of transient and permanent focal cerebral ischemia, as well as arterial thrombosis and bleeding tests, suggest a role for SMTP-7's regulated profibrinolytic action and neuroprotective properties in the monkey MCA occlusion model. In conclusion, SMTP-7 is effective in treating thrombotic stroke in monkeys. SMTP-7 is thus a promising candidate for the development of alternative therapy for ischemic stroke.

Protective Effect of Stachybotrys microspora Triprenyl Phenol-7on the Deposition of IgA to the Glomerular Mesangium in Nivalenol-induced IgA Nephropathy Using BALB/c Mice

Activators of tissue proteolysis including Stachybotrys microspora triprenyl phenol (SMTP)-7 are a new class of agents that are expected to be effective for amelioration of chronic tissue destructive diseases. The present study was performed to examine whether SMTP-7 is effective for the amelioration or protection of early-stage IgA nephropathy (IgAN) induced by nivalenol (NIV) in female BALB/c mice. In Experiment 1, mice were administered NIV at 24 ppm in diet for 8 weeks, and during the NIV treatment, they were intraperitoneally injected with SMTP-7 (10 mg/kg) three times a week. In Experiment 2, mice were injected similarly with SMTP-7 during the last 4 weeks of a 16-week NIV treatment. Immunofluorescence analysis revealed an inhibitory effect of SMTP-7 on the glomerular deposition of IgA in Experiment 1; however, it was ineffective in Experiment 2. On the other hand, SMTP-7 did not affect the serum concentration of IgA in both experiments. These results suggest that SMTP-7 has a potential to decrease the progression of IgAN induced by NIV through inhibition of local accumulation of IgA in the glomerular mesangium, while it was ineffective for suppression of IgA production. On the other hand, SMTP-7 was found to be ineffective for already deposited IgA, suggesting that SMTP-7 may not be effective for ameliorating advanced IgAN.

Salusin-β accelerates inflammatory responses in vascular endothelial cells via NF-κB signaling in LDL receptor-deficient mice in vivo and HUVECs in vitro

The bioactive peptide salusin-β is highly expressed in human atheromas; additionally, infusion of antiserum against salusin-β suppresses the development of atherosclerosis in atherogenic mice. This study examined the roles of salusin-β in vascular inflammation during atherogenesis. Infusion of antiserum against salusin-β attenuated the induction of VCAM-1, monocyte chemoattractant protein (MCP)-1, and IL-1β and as well as nuclear translocation of NF-κB in aortic endothelial cells (ECs) of LDL receptor-deficient mice, which led to the prevention of monocyte adhesion to aortic ECs. In vitro experiments indicated that salusin-β directly enhances the expression levels of proinflammatory molecules, including VCAM-1, MCP-1, IL-1β, and NADPH oxidase 2, as well as THP-1 monocyte adhesion to cultured human umbilical vein ECs (HUVECs). Both salusin-β-induced VCAM-1 induction and monocyte/HUVEC adhesion were suppressed by pharmacological inhibitors of NF-κB, e.g., Bay 11-7682 and curcumin. Furthermore, the VCAM-1 induction was significantly prevented by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY-294002, whereas it was accelerated by the ERK inhibitor, U-0126. Treatment of HUVECs with salusin-β, but not with salusin-α, accelerated oxidative stress and nuclear translocation of NF-κB as well as phosphorylation and degradation of IκB-α, an endogenous inhibitor of NF-κB. Thus, salusin-β enhanced monocyte adhesion to vascular ECs through NF-κB-mediated inflammatory responses in ECs, which can be modified by PI3K or ERK signals. These findings are suggestive of a novel role of salusin-β in atherogenesis.

A new series of the SMTP plasminogen modulators with a phenylamine-based side chain

SMTPs are a family of small-molecule plasminogen modulators that enhance plasminogen activation. SMTP-7, one of the most potent congeners, is effective in treating thrombotic cerebral infarction. The SMTP molecule consists of a tricyclic γ-lactam moiety, a geranylmethyl group, and an N-linked side chain. The presence of both an aromatic group and a negatively ionizable group in the N-linked side chain is crucial for activity. Investigations of the congeners with a phenylglycine-based side chain suggest that a phenolic hydroxy group affects potency. In this study, we isolate and characterize a series of novel SMTP congeners with a phenylamine-based N-linked side chain. Of the 11 congeners isolated, SMTP-19 (with a 4-phenylcarboxylic acid moiety), SMTP-22 (with a 3-hydroxyphenyl-4-carboxylic acid moiety) and SMTP-25 (with a 2-hydroxyphenyl-3-carboxylic acid moiety) are as potent as SMTP-7 in plasminogen-modulating activity. Their isomers with a carboxylic acid group and/or a phenolic hydroxy group at different positions have <40% of the activity of these congeners. Both SMTP-22 and SMTP-25 have >1.7 times more oxygen radical absorbance capacity as compared with SMTP-7.

SMTP (Stachybotrys microspora triprenyl phenol) enhances clot clearance in a pulmonary embolism model in rats

Background

Stachybotrys microspora triprenyl phenols (SMTPs) are a novel family of small molecules that enhance both activation and fibrin-binding of plasminogen. While their effects on fibrinolysis have been characterized in vitro, little is known about their activity in vivo with respect to plasminogen activation and blood clot clearance.

Results

To select a potent SMTP congener for the evaluation of its action in vitro and in vivo, we tested several SMTP congeners with distinct structural properties for their effects on plasminogen activation. As a result, SMTP-7 (orniplabin) was found to have distinguished activity. Several lines of biochemical evidence supported the idea that SMTP-7 acted as a plasminogen modulator. SMTP-7 elevated plasma level of plasmin-α₂-antiplasmin complex, an index of plasmin formation in vivo, 1.5-fold in mice after the intravenous injections at doses of 5 and 10 mg kg^-1. In a rat pulmonary embolism model, SMTP-7 (5 mg kg^-1) enhanced the rate of clot clearance ~3-fold in the absence of exogenous plasminogen activator. Clot clearance was enhanced further by 5 mg kg^-1 of SMTP-7 in combination with single-chain urokinase-type plasminogen activator.

Conclusions

Our results show that SMTP-7 is a superior plasminogen modulator among the SMTP family compounds and suggest that the agent enhances plasmin generation in vivo, leading to clearance of thrombi in a model of pulmonary embolism.

Nox2 oxidase activity accounts for the oxidative stress and vasomotor dysfunction in mouse cerebral arteries following ischemic stroke

Background and Purpose

Post-ischemic oxidative stress and vasomotor dysfunction in cerebral arteries may increase the likelihood of cognitive impairment and secondary stroke. However, the underlying mechanisms of post-stroke vascular abnormalities, as distinct from those causing primary brain injury, are poorly understood. We tested whether augmented superoxide-dependent dysfunction occurs in the mouse cerebral circulation following ischemia-reperfusion, and evaluated the role of Nox2 oxidase.

Methods

Cerebral ischemia was induced in male C57Bl6/J wild-type (WT) and Nox2-deficient (Nox2^-/-) mice by middle cerebral artery occlusion (MCAO; 0.5 h), followed by reperfusion (23.5 h). Superoxide production by MCA was measured by L-012-enhanced chemiluminescence. Nitric oxide (NO) function was assessed in cannulated and pressurized MCA via the vasoconstrictor response to N^ω-nitro-L-arginine methyl ester (L-NAME; 100 µmol/L). Expression of Nox2, the nitration marker 3-nitrotyrosine, and leukocyte marker CD45 was assessed in cerebral arteries by Western blotting.

Results

Following ischemia-reperfusion, superoxide production was markedly increased in the MCA of WT, but not Nox2^-/- mice. In WT mice, L-NAME-induced constriction was reduced by ∼50% in ischemic MCA, whereas ischemia-reperfusion had no effect on responses to L-NAME in vessels from Nox2^-/- mice. In ischemic MCA from WT mice, expression of Nox2 and 3-nitrotyrosine were ∼1.4-fold higher than in the contralateral MCA, or in ischemic or contralateral vessels from Nox2^-/- mice. Vascular CD45 levels were unchanged by ischemia-reperfusion.

Conclusions

Excessive superoxide production, impaired NO function and nitrosative stress occur in mouse cerebral arteries after ischemia-reperfusion. These abnormalities appear to be exclusively due to increased activity of vascular Nox2 oxidase.

Stachybotrys microspora triprenyl phenol-7, a novel fibrinolytic agent, suppresses superoxide production, matrix metalloproteinase-9 expression, and thereby attenuates ischemia/reperfusion injury in rat brain

Stachybotrys microspora triprenyl phenol-7 (SMTP-7) is a novel fibrinolytic agent with anti-inflammatory effect. Previous study demonstrated that SMTP-7 further ameliorated infarction volume in a mouse embolic stroke model compared with tissue type plasminogen activator (tPA), but the reason SMTP-7 has more beneficial effect than tPA has not yet been determined. In the present study, we investigated whether SMTP-7 has an intrinsic neuroprotective effect against transient focal cerebral ischemia (tFCI). Sprague-Dawley rats were subjected to tFCI by intraluminal middle cerebral artery occlusion for 2h. Following induction of tFCI, rats were randomized into two groups based on the agent administered: SMTP-7 group and vehicle group. We examined cerebral infarction volume 24h after reperfusion, and evaluated superoxide production, the expressions of nitrotyrosine and matrix metalloproteinase-9 (MMP-9), which play major roles in secondary brain injury and hemorrhagic transformation. The findings showed that SMTP-7 significantly suppressed superoxide production, the expression of nitrotyrosine and MMP-9 after tFCI, and consequently attenuated ischemic neuronal damage. These results suggest that SMTP-7 has an intrinsic neuroprotective effect on ischemia/reperfusion injury through the suppression of oxidative stress and MMP-9 activation.