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result(s) for
"NARASAKI Ritsuko"
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A new series of the SMTP plasminogen modulators with a phenylamine-based side chain
2012
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.
Journal Article
SMTP (Stachybotrys microspora triprenyl phenol) enhances clot clearance in a pulmonary embolism model in rats
by
Hasumi, Keiji
,
Narasaki, Ritsuko
,
Hu, Weimin
in
Angiology
,
Animal models in research
,
Binding sites
2012
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-α
2
-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.
Journal Article
Structure-activity relationships of 11 new congeners of the SMTP plasminogen modulator
2010
The fungal metabolite
Stachybotrys microspora
triprenyl phenols (SMTPs) are small-molecule plasminogen modulators that enhance plasminogen activation. The SMTP molecule consists of a tricyclic γ-lactam moiety, an isoprene side-chain and an
N
-linked side-chain. Previous investigations have demonstrated that the
N
-linked side-chain is crucial for its activity. In this study, we have isolated 11 new SMTP congeners with a variety of
N
-linked side-chain structures, to investigate structure–activity relationships. Active compounds included congeners with a carboxyl or a sulfonic acid group in the
N
-linked side-chain, whereas not all the congeners with a carboxyl group were active. Of these congeners, that with methionine or tyrosine as the
N
-linked side-chain moiety was more active than that with an aliphatic amino acid. Congeners without ionizable group in the
N
-linked side-chain were essentially inactive.
Journal Article
SMTP
by
Hasumi, Keiji
,
Narasaki, Ritsuko
,
Hu, Weimin
in
Animal models in research
,
Diagnosis
,
Drug therapy
2012
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. 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-[alpha].sub.2 -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.sup.-1.sup.. In a rat pulmonary embolism model, SMTP-7 (5 mg kg.sup.-1.sup.) enhanced the rate of clot clearance ~3-fold in the absence of exogenous plasminogen activator. Clot clearance was enhanced further by 5 mg kg.sup.-1 .sup.of SMTP-7 in combination with single-chain urokinase-type plasminogen activator. 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.
Journal Article