Biology subjects

Hui, P.

Publications and source records attributed to Hui, P..

4 recordsLinked to original sources

bioRxiv2025

MICRORNAS AS REGULATORS OF DRUG METABOLISM AND TRANSPORT IN PREGNANT AND LACTATING WOMEN

BackgroundPhysiological changes during pregnancy result in altered maternal drug metabolism that impacts efficacy and safety of therapeutics in pregnant women. Pregnancy induced hormonal, immunologic, or metabolic changes may also influence and alter drug disposition. Despite research efforts focused on pharmacokinetics of medications used in pregnant women in the past decade, knowledge gaps exist in understanding how pregnancy influences drug disposition and placental drug transporters. Moreover, there is a scarcity of research in understanding the safety and effectiveness of therapeutics in lactating women. This study aimed to determine the effect of pregnancy on levels of miRNAs regulating drug metabolizing enzymes and transporters (DMET). MethodsWe utilized longitudinal serum specimens collected in 3-month intervals from 88 women who became pregnant during follow-up in a large prospective study of hormonal contraception and HIV acquisition in Uganda and Zimbabwe. We used the HTG EdgeSeq platform coupled with Illumina sequencing to obtain the global miRNA transcriptome in paired specimens collected before, during and after pregnancy. To identify differentially expressed (DE) miRNAs that distinguish pregnancy from pre-conception or breastfeeding we used mixed effect model accounting for multiple samples from the pregnancy event and controlling for fixed effects of batch, country, Nugent score category and sexually transmitted infections. To identify hormonally regulated miRNAs independently associated with Box-Cox-transformed levels of progesterone (P4), {beta}-estradiol (E2), and sex-hormone binding protein (SHBG) we controlled in addition for age, pregnancy and breastfeeding P-values were corrected using the Benjamini-Hochberg false discovery rate (FDR). DMET-targeting miRNAs were identified using miRTarBase focusing on interactions verified by 3-UTR luciferase reporter assay and overlapped with DE miRNAs with FDR < 0.05. ResultsOf 140 DMET-targeting miRNAs among the 2079 miRNAs in the global peripheral blood transcriptome, 41 unique DMET-targeting miRNAs were found to be DE during pregnancy - 38 differentiating pregnancy from preconception and 9 differentiating pregnancy from breastfeeding. The 56 DMETs confirmed as targets of the DE miRNAs included 8 members of the ABC (ATP-binding cassette) transporter family, all abundantly expressed in the placenta, and 4 members of the cytochrome P450 Phase 1 enzyme family with major role in xenobiotics detoxification. The study also revealed a strong (FDR<0.05), predominantly positive association between specific DMET-targeting miRNAs and sex hormone-binding globulin (SHBG) levels, suggesting a miRNA-mediated downregulation of DMETs as SHBG levels rise during pregnancy. ConclusionThis research provides crucial insights into the molecular mechanisms underlying altered drug disposition in pregnant and lactating women, paving the way for improved therapeutic management and personalized medicine in these populations.

molecular biology↗

bioRxiv2021

SARS-CoV-2 expresses a microRNA-like small RNA able to selectively repress host genes

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease (COVID-19), continues to be a pressing health concern. In this study, we investigated the impact of SARS-CoV-2 infection on host microRNA (miRNA) populations in three human lung-derived cell lines, as well as in nasopharyngeal swabs from SARS-CoV-2 infected individuals. We did not detect any major and consistent differences in host miRNA levels after SARS-CoV-2 infection. However, we unexpectedly discovered a viral miRNA-like small RNA, named vmiR-5p (for viral miRNA), derived from the SARS-CoV-2 ORF7a transcript. Its abundance ranges from low to moderate as compared to host miRNAs. vmiR-5p functionally associates with Argonaute proteins -- core components of the RNA interference pathway -- leading to downregulation of host transcripts. One such host messenger RNA encodes Basic Leucine Zipper ATF-Like Transcription Factor 2 (BATF2), which is linked to interferon signaling. We demonstrate that vmiR-5p production relies on cellular machinery, yet is independent of Drosha protein, and is enhanced by the presence of a strong and evolutionarily conserved hairpin formed within the ORF7a sequence. Significance statementWe discovered that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) expresses a small viral non-coding RNA, named vmiR-5p (for viral miRNA), derived from the ORF7a transcript. vmiR-5p associates with the cellular RNA interference machinery to regulate host transcripts likely via target silencing. The production of vmiR-5p relies on cellular machinery and the formation of a strong hairpin within ORF7a sequences. This newly-described vmiR-5p may contribute to SARS-CoV-2 pathogenesis and could become a target for therapeutic intervention.

microbiology↗

bioRxiv2020

Vulnerability of ARID1A deficient cancer cells to pyrimidine synthesis blockade

Here we report the discovery and preclinical validation of a novel precision medicine strategy for ARID1A-mutated cancer. Unbiased proteomics reveals for the first time that ARID1A protein (BAF250a) binds aspartate transcarbamoylase (ATCase), a key regulatory enzyme of the de novo pyrimidine synthesis pathway. Using isogenic paired ARID1A proficient/deficient cancer cell lines, we show that ARID1A protein deficiency (as occurs in ARID1A mutant cancers) leads to metabolic reprogramming and pyrimidine synthesis dependency. Pyrimidine synthesis blockade using the FDA-approved drug teriflunomide (a DHODH inhibitor) suppresses tumor growth and selectively induces DNA damage in ARID1A-deficient tumor models. Combining pyrimidine synthesis inhibition with DNA damage repair blockade, using teriflunomide and AZD6738 (an ATR inhibitor), achieves potent synergy and induces sustained tumor regression in ARID1A-mutant ovarian cancer patient-derived xenografts (PDX). These compelling preclinical data support the evaluation of this novel combination treatment in patients with ARID1A-mutated cancers. SIGNIFICANCEWe identified that ARID1A-deficient cells are selectively vulnerable to pyrimidine synthesis blockade. Preclinical studies demonstrate the in vivo efficacy of a synergistic drug combination that concurrently inhibits the de novo pyrimidine synthesis pathway and DNA damage repair to induce regression in patient-derived xenograft models of ARID1A-mutated cancer.

cancer biology↗

bioRxiv2016

The origin and evolution of a pandemic lineage of the kiwifruit pathogen Pseudomonas syringae pv. actinidiae

Recurring epidemics of kiwifruit (Actinidia spp.) bleeding canker disease are caused by Pseudomonas syringae pv. actinidiae (Psa), whose emergence coincided with domestication of its host. The most recent pandemic has had a deleterious effect on kiwifruit production worldwide. In order to strengthen understanding of population structure, phylogeography and evolutionary dynamics of Psa, we sampled 746 Pseudomonas isolates from cultivated and wild kiwifruit across six provinces in China, of which 87 were Psa. Of 234 Pseudomonas isolated from wild Actinidia spp. none were identified as Psa. Genome sequencing of fifty isolates and the inclusion of an additional thirty from previous studies show that China is the origin of the recently emerged pandemic lineage. However China harbours only a fraction of global Psa diversity, with greatest diversity found in Korea and Japan. Distinct transmission events were responsible for introduction of the pandemic lineage of Psa into New Zealand, Chile and Europe. Two independent transmission events occurred between China and Korea, and two Japanese isolates from 2014 cluster with New Zealand Psa. Despite high similarity at the level of the core genome and negligible impact of within-lineage recombination, there has been substantial gene gain and loss even within the single clade from which the global pandemic arose.\n\nSIGNIFICANCE STATEMENTBleeding canker disease of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) has come to prominence in the last three decades. Emergence has coincided with domestication of the host plant and provides a rare opportunity to understand ecological and genetic factors affecting the evolutionary origins of Psa. Here, based on genomic analysis of an extensive set of strains sampled from China and augmented by isolates from a global sample, we show, contrary to earlier predictions, that China is not the native home of the pathogen, but is nonetheless the source of the recent global pandemic. Our data identify specific transmission events, substantial genetic diversity and point to non-agricultural plants in either Japan or Korea as home to the source population.

epidemiology↗