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  • Author: Supeecha Wittayalertpanya x
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Open access

Wanmai Moleephan, Supeecha Wittayalertpanya, Nijsiri Ruangrungsi and Wacharee Limpanasithikul

Abstract

Background: Reduced production of melanin and decreased or absence of melanocytes leads to various hypopigmentation disorders. Melanin synthesis is regulated by melanogenic proteins such as tyrosinase, tyrosinase-related protein 1 (TRP-1) and tyrosinase-related protein 2 (TRP -2), as well as their transcription factors.

Objectives: This study elucidated the effects of xanthoxylin on melanin content, dendriticity, melanogenic protein expression and its signal transduction pathways in mouse B16F10 melanoma cells (B16F10 cells).

Methods: Melanin production of B16F10 cells was measured by using a melanin content assay. The effect of xanthoxylin on the dendriticity of B16F10 cells was determined by a melanocyte dendricity assay. RT-PCR was used to investigate the effects of xanthoxylin on the melanogenic protein expression.

Results: We found that xanthoxylin increased melanin production, number of dendrites, tyrosinase, and microphthalmia-associated transcription factor (MITF) expression in cultured B16F10 cells. In addition, PKA and PKC inhibitor decreased melanin production, tyrosinase, and MITF expression in xanthoxylin-treated cells. However, xanthoxylin did not inhibit TRP-1 and TRP-2 expression.

Conclusion: These results indicated that xanthoxylin induces melanogenesis mainly via cAMP-mediated PKA activation. Other signaling pathways may also play a role in xanthoxylin-induced melanogenesis.

Open access

Kreetachon Veerakikosol, Pajaree Chariyavilaskul, Natavudh Townamchai and Supeecha Wittayalertpanya

Abstract

Background

Cytochrome P450 (CYP) 3A5 is a major isoform metabolizing tacrolimus. Individual variation in the metabolism may result from CYP3A5 single nucleotide polymorphisms (SNPs). CYP3A5*3 polymorphism is strongly associated with tacrolimus pharmacokinetic variations in 65%–85% of Asian populations. A minor polymorphism related to requirement for tacrolimus is the POR*28 mutation, which increases in vivo CYP3A activity for tacrolimus. These two SNPs might affect individual maintenance dosages of tacrolimus.

Objectives

To determine the association of CYP3A5*3 and POR*28 SNPs with maintenance dosage requirements for tacrolimus in Thai recipients of kidney transplants.

Methods

We enrolled 150 Thai recipients of kidney transplants. Clinical laboratory data were recorded 3 months after first administration of tacrolimus. Two SNPs; rs776746 A > G (CYP3A5*3 allele) and rs1057868 C > T (POR*28 allele) were assessed. All 300 genotypes were analyzed by real-time polymerase chain reactions.

Results

Recipients were classified into 9 groups according to possible matching genotypes. The mean dosage required for the maintenance phase was significantly higher in the CYP3A5*1 allele or CYP3A5 expressers (groups 1-6, 0.163, 0.167, 0.141, 0.128, 0.131, and 0.174 mg/kg/day, respectively) than those not expressing CYP3A5*3/*3 or CYP3A5 (groups 7-9, 0.081, 0.073, and 0.069 mg/kg/day, respectively, P < 0.05). When the mean dosage was compared under POR*28 one or two alleles in CYP3A5 expressers, P was significantly smaller than in CYP3A5 expressers with POR*1/*1.

Conclusions

CYP3A5 polymorphism is key to determining tacrolimus dosage requirements during the maintenance phase in kidney transplant recipients and POR*28 may contribute to the interindividual variability

Open access

Chayapol Somboonyosdech, Supeecha Wittayalertpanya, Udomsak Bunworasate and Wacharee Limpanasithikul

Abstract

Background: Rituximab is a chimeric IgG1 monoclonal antibody against CD20, approved for the treatment of B-cell non-Hodgkin’s lymphoma (NHL). Antibody dependent cellular cytotoxicity (ADCC) has been suggested to be an important mechanism of rituximab via binding to the Fc gamma IIIa receptor (FcγRIIIa) on natural killer (NK) cells. FcγRIIIa has two expressed alleles that differ at amino acid position 158 in the extracellular domain, valine (V158) and phenylalanine (F158). These allelic variants have been demonstrated to differ in IgG1 binding and ADCC. V/V homozygotes and V/F heterozygotes bind to IgG with higher affinity than F/F homozygotes.

Objectives: We identified the frequencies of FcγRIIIa polymorphism and investigate the correlation between FcγRIIIa polymorphism and rituximab responses, both in vitro and in vivo in Thai population.

Methods: The RFLP-Nested PCR and allele specific amplification was used to identify the FcγRIIIa polymorphism in the study. The correlation between FcγRIIIa polymorphism and rituximab responses, both in vitro and in vivo, was also studied.

Results: The distributions of FcγRIIIa-158 polymorphism in these subjects are V/V 40.26%, V/F 16.88%, and F/F 42.86%. Higher rituximab-induced Ramos cell cytotoxicity (mean 33.16%, 36.87%) was observed in the subjects with VV and VF genotypes, respectively. However, the lower cytotoxicity (mean 20.07%) was determined in subjects with FF genotype. As for the in vivo study, the NHL patients with V/V or V/F genotypes had a primary response as complete response; whereas, the NHL patients with F/F genotype had partial response.

Conclusion: FcγRIIIa polymorphism and the primary response in NHL patients tend to correlate. The higher number of patients is necessary for further study. These results provide useful information to understand beneficial response of rituximab as well as other IgG1 therapeutic antibody in Thai patients.

Open access

Thassanee Vongnam, Supeecha Wittayalertpanya, Nijsiri Raungrungsi and Wacharee Limpanasithikul

Abstract

Background: Deiris reticulata Craib is a Thai medicinal plant in the Legiuninosae family. It has flavonoids as major active compounds similar to other plants in genus Denis. Several flavonoids have been identified to have anti-inflammatory activities. The anti-inflammatory mechanisms and potency of flavonoids from this medicinal plant is not known.

Objective: We investigated the effect of ethanolic extract fr om stem of D. reticulata on LPS-induced macrophage activation.

Methods: J774A.1 cells were treated with 6.25-100 g/ml the extract for 24 horns and then activated with 100 ng/ml lipopolysaccharide (LPS) for 24 horns. Tire extract inhibited nitric oxide production in LPS-activated J774A. 1 cells in concentration-dependent maimer with IC50 62.5 μg/ml. The effect of this extract on phagocytosis activity of LPS-activated J774A. 1 cells was also investigated.

Results: The extract at concentrations of 50 and 100 pg/ml significantly inhibited zymosan phagocytosis of LPS-activated cells in a concentration dependent maimer. It decreased the mRNA expression of the inducible nitric oxide synthase (iNOS) which plays a role in NO production and the cyclo-oxygenase 2 (COX-2) which is responsible for prostaglandins (PGs) production in LPS-activated J774A. 1 cells. This extract also inhibited the mRNA expression of pro-inflammatory cytokines. TNF-α. IL-β and IL-6 in the LPS-activated J774A. 1 cells.

Conclusion: The results hi this study reveal for the first time that the ethanolic extract of D. reticulata stem has potential anti-inflammatory activity. It inhibited production of several known inflammatory mediators in LPS-activated macrophages. These findings may be useful to study this plant further as a source of anti­inflammatory activity.