Anti-CYP3A4 (aa 234-264) polyclonal antibody

Cytochrome P450 (CYP) enzymes are involved in the biotransformation of chloroquine (CQ), but the role of the different profiles of metabolism of this drug in relation to Plasmodium vivax recurrences has not been properly investigated. To investigate the influence of the CYP genotypes associated with CQ metabolism on the rates of P. vivax early recurrences, a case-control study was carried out. The cases included patients presenting with an early recurrence (CQ-recurrent individuals), defined as a recurrence during the first 28 days after initial infection and plasma concentrations of CQ plus desethylchloroquine (DCQ; the major CQ metabolite) higher than 100 ng/ml. A control group with no parasite recurrence over the follow-up (the CQ-responsive group) was also included. CQ and DCQ plasma levels were measured on day 28. CQ-metabolizing CYP (CYP2C8, CYP3A4, and CYP3A5) genotypes were determined by real-time PCR. An ex vivo study was conducted to verify the efficacy of CQ and DCQ against P. vivax isolates. The frequency of alleles associated with normal and slow metabolism was similar between the cases and the controls for the CYP2C8 (odds ratio [OR] = 1.45, 95% confidence interval [CI] = 0.51 to 4.14, P = 0.570), CYP3A4 (OR = 2.38, 95% CI = 0.92 to 6.19, P = 0.105), and CYP3A5 (OR = 4.17, 95% CI = 0.79 to 22.04, P = 1.038) genes. DCQ levels were higher than CQ levels, regardless of the genotype. Regarding the DCQ/CQ ratio, there was no difference between groups or between those patients who had a normal genotype and those patients who had a mutant genotype. DCQ and CQ showed similar efficacy ex vivo. CYP genotypes had no influence on early recurrence rates. The similar efficacy of CQ and DCQ ex vivo could explain the absence of therapeutic failure, despite the presence of alleles associated with slow metabolism.

Endoplasmic reticulum stress (ER stress) leads an unfolded protein response (UPR) which results in internal cellular responses such as proteostasis and protein clearance. Recently, several reports demonstrated that the ER stress in stem cells could affect their stemness and fates to differentiate into certain lineages. However, the potential for controlling differentiation and function of cells by regulating ER stress needs to be further addressed. Here, we demonstrated that relieving the ER stress in cell cultures enhances the functionalities of hPSC-derived hepatocytes and other hepatic cells to be used in various research fields. Firstly, we found that UPR genes were up-regulated during hepatic differentiation of hPSCs and treatment of ER stress reliever at the hepatic induction stage of the differentiation resulted the enhanced mature marker expressions and glycogen storage of the differentiated hepatocytes. The treatment of ER stress reliever also improved the maintenance of hepatic characteristics in long-term culture of hPSC-derived hepatocytes. Furthermore, relieving ER stress increased the hepatic marker expression and CYP3A4 activity in hepatoma cell lines and human primary hepatocytes. Taken together, our findings indicate that regulating ER stress of in vitro cultured hepatocytes might be a crucial factor for enhancing differentiation, function and maintaining hepatic identity.