Plasmodium vivax merozoite-specific thrombospondin-related anonymous protein (PvMTRAP) interacts with human CD36, suggesting a novel ligand-receptor interaction for reticulocyte invasion.

BACKGROUND: The Plasmodium vivax merozoite restrictively invades immature erythrocytes, suggesting that its ligand(s) might interact with corresponding receptor(s) that are selectively abundant on reticulocytes to complete the invasion. Finding the ligand‒receptor interaction involved in P. vivax invasion is critical to vivax malaria management; nevertheless, it remains to be unraveled. METHODS: A library of reticulocyte receptors and P. vivax ligands were expressed by a HEK293E mammalian cell expression system and were then used to screen the interaction using enzyme-linked immunosorbent assay (ELISA). A flow cytometry-based erythrocyte binding assay and bio-layer interferometry experiment were further utilized to cellularly and quantitatively identify the ligand‒receptor interaction, respectively. RESULTS: Plasmodium vivax merozoite-specific thrombospondin-related anonymous protein (PvMTRAP) was found to interact with human CD36 using systematic screening. This interaction was specific at a molecular level from in vitro analysis and comparable to that of P. vivax Duffy binding protein (PvDBP) and Duffy antigen receptor for chemokines (DARC) (KD: 37.0 ± 1.4 nM and 7.7 ± 0.5 nM, respectively). Flow cytometry indicated that PvMTRAP preferentially binds to reticulocytes, on which CD36 is selectively present. CONCLUSIONS: Human CD36 is selectively abundant on reticulocytes and is able to interact specifically with PvMTRAP, suggesting that it may function as a ligand and receptor during the invasion of reticulocytes by P. vivax.

An Integrated Approach for the Efficient Extraction and Solubilization of Rice Microsomal Membrane Proteins for High-Throughput Proteomics.

The preparation of microsomal membrane proteins (MPs) is critically important to microsomal proteomics. To date most research studies have utilized an ultracentrifugation-based approach for the isolation and solubilization of plant MPs. However, these approaches are labor-intensive, time-consuming, and unaffordable in certain cases. Furthermore, the use of sodium dodecyl sulfate (SDS) and its removal prior to a mass spectrometry (MS) analysis through multiple washing steps result in the loss of proteins. To address these limitations, this study introduced a simple micro-centrifugation-based MP extraction (MME) method from rice leaves, with the efficacy of this approach being compared with a commercially available plasma membrane extraction kit (PME). Moreover, this study assessed the subsequent solubilization of isolated MPs in an MS-compatible surfactant, namely, 4-hexylphenylazosulfonate (Azo) and SDS using a label-free proteomic approach. The results validated the effectiveness of the MME method, specifically in the enrichment of plasma membrane proteins as compared with the PME method. Furthermore, the findings showed that Azo demonstrated several advantages over SDS in solubilizing the MPs, which was reflected through a label-free quantitative proteome analysis. Altogether, this study provided a relatively simple and rapid workflow for the efficient extraction of MPs with an Azo-integrated MME approach for bottom-up proteomics.

miR-141 is up-regulated in biopsies from Vietnamese patients with nasopharyngeal carcinoma.

Novel biomarkers for screening, diagnosis and monitoring the treatment of nasopharyngeal carcinoma (NPC), one of the most common cancers in Vietnam, are urgently required. Increasing evidence suggests that microRNA-141 (miR-141) is associated with NPC, owing to its ability to affect the expression of genes that modulate tumorigenesis. Unfortunately, research on miR-141 expression in Vietnamese patients is limited. Therefore, the objective of the current study was to evaluate miR-141 expression and assess whether miR-141 might be a potential biomarker for diagnosis of NPC in Vietnamese patients. Total RNA isolated from 40 NPC biopsy samples and 37 non-cancerous samples was analyzed by quantitative reverse-transcription PCR. The miR-141 expression levels were compared between NPC biopsy and non-cancerous samples. The frequency of miR-141 detection was 37.50% and 10.80% in the NPC and non-cancerous samples, respectively (p = 0.0143). The miR-141 expression was 5.27 times higher in tumor samples than non-cancerous samples. Additionally, the RR (Relative risk) and OR (Odds ratio) were 1.83 (95%CI = 1.2576-2.6675, p = 0.0016) and 4.95 (95%CI = 1.4625-16.7541, p = 0.01), respectively. In conclusion, miR-141 was up-regulated in the biopsy samples and thus may be a potential biomarker for NPC in the Vietnamese population.

Rubella epidemic in Vietnam: characteristic of rubella virus genes from pregnant women and their fetuses/newborns with congenital rubella syndrome.

BACKGROUND: Rubella remains poorly controlled in Southeast Asia, including Vietnam. OBJECTIVES: The aim of this study was to characterize rubella virus spread in Vietnam during 2011-2012. STUDY DESIGN: Amniotic fluid, throat swab and placenta samples were collected from 130 patients (110 cases from pregnant women with suspected rubella and 20 cases from fetuses/newborns). Viral RNA was obtained directly from clinical specimens, amplified by PCR, and then the E1 gene containing 739 nucleotides recommended by the WHO to identify the viral genotypes was sequenced. RESULTS: By screening with real-time PCR, viral RNA was detectable in amniotic fluids from 103 out of 110 (93.6%) pregnant women with suspected rubella and in the throat swabs from all of 20 (100%) fetuses/newborns. In addition, viral RNA was also detected in the placenta from all cases of fetuses/newborns. All of 20 fetuses/newborns presented with congenital cataract. Twenty-four strains with the E1 gene were obtained by PCR. Using phylogenetic analysis with rubella reference sequences, all of the strains were found to be genotype 2B. Interestingly, 94% (30/32) of Vietnamese strains, including 9 strains from the database, formed an independent cluster within the genotype 2B suggesting that indigenous viruses are prevalent in this region. CONCLUSIONS: Rubella virus identified in Vietnam belonged to the genotype 2B. Importantly, the infection rate of rubella virus in fetuses/newborns was 100% and all of them had congenital cataract. Our results indicate an establishment of rubella prevention in this area is an urgent task in order to improve maternal and child health.

miR-141 is up-regulated in biopsies from Vietnamese patients with nasopharyngeal carcinoma

Abstract: Novel biomarkers for screening, diagnosis and monitoring the treatment of nasopharyngeal carcinoma (NPC), one of the most common cancers in Vietnam, are urgently required. Increasing evidence suggests that microRNA-141 (miR-141) is associated with NPC, owing to its ability to affect the expression of genes that modulate tumorigenesis. Unfortunately, research on miR-141 expression in Vietnamese patients is limited. Therefore, the objective of the current study was to evaluate miR-141 expression and assess whether miR-141 might be a potential biomarker for diagnosis of NPC in Vietnamese patients. Total RNA isolated from 40 NPC biopsy samples and 37 non-cancerous samples was analyzed by quantitative reverse-transcription PCR. The miR-141 expression levels were compared between NPC biopsy and non-cancerous samples. The frequency of miR-141 detection was 37.50% and 10.80% in the NPC and non-cancerous samples, respectively (p = 0.0143). The miR-141 expression was 5.27 times higher in tumor samples than non-cancerous samples. Additionally, the RR (Relative risk) and OR (Odds ratio) were 1.83 (95%CI = 1.2576-2.6675, p = 0.0016) and 4.95 (95%CI = 1.4625-16.7541, p = 0.01), respectively. In conclusion, miR-141 was up-regulated in the biopsy samples and thus may be a potential biomarker for NPC in the Vietnamese population.