Cardiovascular effect of a naphthylmethyl substituted tetrahydroisoquinoline, YS 49, in rat and rabbit

Effects of the anti-sepsis drug, (S)-1-(α-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CKD-712), on mortality, inflammation, and organ injuries in rodent sepsis models

CKD-712 is a 1-naphthyl analog of higenamine that has been reported to have potent antiinflammatory and thus anti-sepsis effects. The purpose of this study was to investigate the potential of CKD-712 as a medicine for sepsis and to confirm its protective effects on organs in animal sepsis models. Pretreatment with CKD-712 dose-dependently increased survival rate in a lipopolysaccharide-induced sepsis model in mice. Body temperature decrease, an important pre-symptom of septic death, was also prevented by CKD-712. CKD-712 still significantly increased survival rate even when administered one and four hours after lipopolysaccharide injection. Therapeutic efficacy of CKD-712 was also confirmed against sepsis following zymosan-induced endotoxemia and in cecal ligation and puncture surgery in mice. In a disseminated intravascular coagulation model in rats, CKD-712 showed organ-protective effect by reducing serum glutamate-oxaloacetate transaminase, glutamate-pyruvate transferase, blood urea nitrogen, and creatinine levels. CKD-712 also prevented histological damage to the lung and liver. In this same model, CKD-712 showed anti-inflammatory effects through decreases in tumor necrosis factor-α and interleukin-6 in the blood and reduced translocation of nuclear factor-κB to the nuclei of lung cells. CKD-712 administration also diminished infiltration of leukocytes into the lung and liver. Taken together, these results show that CKD-712 has excellent potential as an effective medicine for sepsis.

CKD712, (S)-1-(α-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, inhibits the lipopolysaccharide-stimulated secretion of HMGB1 by inhibiting PI3K and classical protein kinase C

CKD712, (S)-1-(α-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, was considered as a new effective drug candidate to sepsis, based on its anti-inflammatory activity. It was reported that CKD712 inhibited various signal pathways which play a key role in production of proinflammatory cytokines. Here, we examined the effect of CKD712 on the secretion of high mobility group box 1 (HMGB1), which is one of the proinflammatory cytokines. CKD712 can reduce Gram-negative lipopolysaccharide (LPS)- and Gram-positive lipoteichoic acid (LTA)-stimulated HMGB1 secretion in RAW264.7 and human peripheral blood monocytes (PBMo), and also reduce LPS-induced nucleocytoplasmic translocation of HMGB1 1h before or after LPS treatment. CKD712 could dose-dependently inhibit the activation of PI3K and PI3K-dependent kinase 1 (PDK1), which are involved in HMGB1 secretion signaling pathway. In addition, CKD712 inhibited classical protein kinase C (cPKC), the effective kinase for phosphorylation of HMGB1 for secretion, however, had no effect on histone acetyl-transferase activity, which is another mechanism known for HMGB1 secretion. Thus, we suggest that CKD712 could inhibit LPS- and LTA-stimulated HMGB1 secretion through the inhibition of HMGB1 phosphorylation by inhibiting PI3K-PKC signaling pathway.

YS 49, 1-(alpha-naphtylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, regulates angiotensin II-stimulated ROS production, JNK phosphorylation and vascular smooth muscle cell proliferation via the induction of heme oxygenase-1

Overexpression of the gene for heme oxygenase (HO)-1 leads to a reduction in pressor responsiveness to angiotensin II (Ang II) in experimental animals. Using rat vascular smooth muscle cells (VSMCs), we tested whether YS 49 [1-(alpha-naphtylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline] inhibits Ang II-stimulated proliferation of VSMCs via induction of HO-1. YS 49 induced HO-1 protein production in a dose-and time-dependent manner in VSMCs. Treatment with YS 49 significantly and dose-dependently inhibited Ang II-induced VSMC proliferation, ROS production, and phosphorylation of JNK, but not P38 MAP kinase or ERK1/2. The antiproliferation effect of YS 49 was reversed by pretreatment with the HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX), or with hemoglobin, a carbon monoxide (CO) scavenger. Similarly, VSMC proliferation, ROS production and phosphorylation of JNK by Ang II were significantly inhibited in VSMCs transfected with the HO-1 gene. Thus, HO-1 and the HO-1 product CO play, at least in part, a crucial role in Ang II-stimulated VSMC proliferation through the regulation of ROS production and JNK phosphorylation. Therefore, YS 49 has potential as a therapeutic strategy for the pathogenesis of Ang II-related vascular diseases such as hypertension and atherosclerosis, via the induction of HO-1 gene activity.

Effects of higenamine and its 1-naphthyl analogs, YS-49 and YS-51, on platelet TXA2 synthesis and aggregation

The effects of higenamine and its 1-naphthyl analogs, YS-49 and YS-51, on thromboxane A(2) (TXA(2)) formation from arachidonic acid (AA) and aggregation in platelets, were investigated. YS-49 and YS-51 (IC(50); 32.8 and 39.4 microM respectively) exhibited much stronger inhibitory effects on TXA(2) formation than higenamine (IC(50); 2.99 mM). The higher inhibitory potencies of YS-49 and YS-51 (IC(50): 3.3 and 5.7 microM respectively) than higenamine (IC(50): 140 microM) on AA induced rat platelet aggregation was presumed to be the result of low inhibitory effect of higenamine than YS-49 and YS-51 on TXA(2) production from AA. Among the present three compounds, the more hydrophobic naphthylmethyl groups were supposed to be more favorable than p-hydroxybenzyl moiety, at 1-position of the tetrahydroisoquinoline ring, to display the inhibitory effects on TXA(2) production and AA induced aggregation of platelets. In addition, higenamine, YS-49 and YS-51 were observed directly antagonistic on TXA(2) receptor (TP receptors) by displaying inhibitory effects to U46619 (TXA(2) mimetic) induced platelet aggregation, however all of the three compounds showed similar order of inhibitory potencies. The present results are suggestive that YS-49 and YS-51 exert their inhibitory effects on AA-induced platelet aggregation partly by inhibiting the production of TXA(2) from AA and partly by directly blocking the TP receptor, in addition to the previously reported effects on alpha(2)-adrenergic receptor. On the other hand, higenamine is supposed to antagonize AA-induced platelet aggregation by mostly directly blocking the TP receptor.

Antithrombotic effects of YS-49 and YS-51--1-naphthylmethyl analogs of higenamine

The antiplatelet and antithrombotic effects of YS-49 and YS-51--l-naphthylmethyl analogs of higenamine, which is a benzyl-tetrahydroisoquinoline alkaloid isolated from Aconitum japonicum (Ranunculaceae)--were investigated. YS-49 and YS-51 showed inhibitory activities to both human and rat platelet aggregation induced by ADP, collagen and epinephrine. They were more inhibitory to epinephrine-induced aggregation (IC(50); 3.4 and 1.7 microM of YS-49, and 6.0 and 6.3 microM of YS-51 to human and rat platelets, respectively) than ADP- or collagen-induced aggregation. The antithrombotic effects of YS-49 and YS-51 were also observed in both mouse acute thrombosis model and rat arterio-venous shunt (AV shunt) model. The oral administration of YS-49 and YS-51 (50 or 100 mg/kg) increased the recovery rates from the acute thrombotic challenge in mice and lowered the weight of thrombus formed inside the AV shunt tube in rats.

Prevention of the expression of inducible nitric oxide synthase by a novel positive inotropic agent, YS 49, in rat vascular smooth muscle and RAW 264.7 macrophages

1 The effects of a novel positive inotropic isoquinoline compound, YS 49, on NO production and iNOS protein expression were investigated in cultured rat aortic vascular smooth muscle cells (RAVSMC) and RAW 264.7 cells exposed to lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma). In addition, the effects of YS 49 on vascular hyporeactivity in vitro and ex vivo, and on survival rate (mice) and serum NOx (rat) levels, were also investigated in LPS-treated animals. 2 Pre- or co-treatment of YS 49 with LPS plus IFN-gamma, concentration-dependently reduced NO production in RAVSMC and RAW 264.7 cells (IC50 values, 22 and 30 microM, respectively). Although the inhibitory effect on NO production was reduced when YS 49 was applied 2 and 4 h after cytokine in RAW 264.7 cells, it was still statistically significant (P<0.05). 3 YS 49 reduced iNOS mRNA expression in LPS-treated rat aorta in vitro, an effect which was associated with restoration of contractility to the vasoconstrictor, phenylephrine (PE), and reduction in L-arginine-induced relaxation. 4 Serum NOx levels were significantly (P<0.01) reduced by YS 49 (5 mg kg-1, i.p.) in LPS-treated rats (10 mg kg-1, i.p.). Administration of YS 49 (10 and 20 mg kg-1) 30 min prior to LPS (10 mg kg-1) also significantly (P<0.01) increased the subsequent survival rates in mice. 5 Finally, expression of iNOS protein induced by LPS plus IFN-gamma in RAVSMC and RAW 264.7 cells was suppressed by YS 49, in a concentration-dependent manner. 6 These data strongly suggest that YS 49 suppresses iNOS gene expression induced by LPS and/or cytokines in RAVSMC and RAW 264.7 cells at the transcriptional level. YS 49 could therefore be beneficial in septic shock and other diseases associated with iNOS over-expression.