HDAC2 was involved in placental P-glycoprotein regulation both in vitro and vivo

Long noncoding RNA UCA1 promotes the expression and function of P-glycoprotein by sponging miR-16-5p in human placental BeWo cells

Investigations on placental P-glycoprotein (P-gp) regulation could provide more therapeutic targets for individualized and safe pharmacotherapy during pregnancy. The role of long noncoding RNA (lncRNA) on placental P-gp regulation is lacking. The present study was carried out to investigate the regulation and underlying mechanisms of lncRNA urothelial carcinoma associated 1 (UCA1) on P-gp in Bewo cells. lncRNA UCA1 inhibition or overexpression could decrease or increase ABCB1 mRNA expression, P-gp expression and its cellular efflux function, respectively. RNA-FISH revealed that lncRNA UCA1 was mainly located in the cytoplasm of Bewo cells. MicroRNA array was applied and 10 significant miRNAs was identified after lncRNA UCA1 inhibition. Databases of LncTarD, LncRNA2Target, and miRcode were further used to search potential target miRNAs of lncRNA UCA1 and miR-16-5p was screened out. Thereafter, we confirmed that miR-16-5p expression was significantly upregulated or reduced after lncRNA UCA1 knockdown or overexpression, respectively. Furthermore, we also proved that ABCB1 mRNA expression, P-gp expression and its cellular efflux function was enhanced or reduced after miR-16-5p inhibition or overexpression, respectively. The rescue experiment further indicated that miR-16-5p was involved in the positive regulation of lncRNA UCA1 on the expression and function of P-gp. Lastly, dual-luciferase reporter system, RNA-binding protein immunoprecipitation and RNA pull-down assays were performed to explore the relationships among lncRNA UCA1, miR-16-5p, and ABCB1. It was found that lncRNA UCA1(1103-1125) could directly interact with miR-16-5p and miR-16-5p could directly target ABCB1 coding DNA sequence region (882-907). In conclusion, LncRNA UCA1 could promote the expression and function of P-gp by sponging miR-16-5p in BeWo cells.

MicroRNA-495 suppresses pre-eclampsia via activation of p53/PUMA axis

Linkage between microRNAs (miRNAs) and pre-eclampsia (PE) has been documented. Here, we focused on miR-495 in PE and its underlying mechanism in regulation of trophoblast cells. Expression of miR-495, HDAC2, p53 and PUMA was determined in collected placental tissue samples. Loss- and gain-function was performed to determine the roles of miR-495, HDAC2, p53, and PUMA in biological processes of HTR8/SVneo cells and primary trophoblast cells. The relationships among miR-495, HDAC2, and p53 were pinpointed. PE patients presented with higher expression of miR-495, p53, and PUMA in placental tissues, but lower HDAC2. miR-495 negatively targeted HDAC2 expression. HDAC2 suppressed p53 expression via deacetylation. Overexpression of miR-495, p53, or PUMA inhibited biological properties of HTR8/SVneo cells and primary trophoblast cells, while opposite trends were observed in response to oe-HDAC2. In conclusion, miR-495 knockdown can suppress p53/PUMA axis by targeting HDAC2 to enhance biological behaviors of trophoblast cells, which may prevent occurrence of PE.

Role of P-gp and HDAC2 and their Reciprocal Relationship in Uncontrolled Asthma

INTRODUCTION

Resistance to corticosteroid is an essential mechanism in uncontrolled asthma as the corticosteroid is the mainstay of therapy. There are recent reports that epigenetic factors play a crucial role in the regulation of steroid action. Overexpression of P glycoprotein (P-gp) and reduced expression of Histone Deacetylase 2 (HDAC2) have been linked to regulating the steroid action in other diseases like Nephrotic Syndrome (NS). However, their role in uncontrolled asthma is still not clear and warrants further investigation. We evaluated the expression and activity of P-gp and HDAC2 in patients with Controlled Asthma (CA) and Uncontrolled Asthma (UA).

METHODS

A total of 60 CA (mean age 51.72±17.02 years, male=38), and 38 of UA (mean age=53.55±11.90 years, male=17) were recruited. The level of control was defined according to (Global Initiative for Asthma) GINA 2016 criteria. The mRNA expression of HDAC2 and P-gp was studied by quantitative real-time Polymerase Chain Reaction (PCR), the functional activity of P-gp was evaluated by a commercially available kit via flow cytometry, and HDAC2 enzymatic activity was measured by commercially available kit by Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS

P-gp expression and the functionality were significantly higher in the UA group of patients as compared to the CA group of patients (p<0.005), moreover HDAC2 expression was significantly reduced in UA patients as compared to CA patients, (p<0.005). The enzymatic activity of HDAC2 was also significantly reduced in UA patients as compared to CA patients (p<0.005).

CONCLUSION

P-gp overexpression and HDAC2 under expression play an essential role in uncontrolled asthma by impairing the response to corticosteroid.

Social Determinants of Placental Health and Future Disease Risks for Babies

Birthweight is a well-known predictor of adult-onset chronic disease. The placenta plays a necessary role in regulating fetal growth and determining birth size. Maternal stressors that affect placental function and prenatal growth include maternal overnutrition and undernutrition, toxic social stress, and exposure to toxic chemicals. These stressors lead to increased vulnerability to disease within any population. This vulnerability arises from placental and fetal exposure to stressors during fetal life. The biological drivers linking various social determinants of health to compromised placental function and fetal development have been little studied.

Elevated miR-23a impairs trophoblast migration and invasiveness through HDAC2 inhibition and NF-κB activation

Preeclampsia (PE) is a pregnancy-specific disorder characterized by the onset of hypertension and proteinuria with onset after the 20th week of gestation. The pathogenesis of PE is attributed to increased trophoblast cell death and poor trophoblast migration/invasiveness. This study investigates the function of microRNA-23a (miR-23a) in PE and its effects on migration and invasion of trophoblast cells HTR-8/SVneo. We found higher expression of miR-23a in placental tissue samples from PE pregnant women compared to samples from normal pregnant women. Enhancing miR-23a expression by its specific mimic reduced HTR-8/SVneo cell migration and invasion and increased HTR-8/SVneo cell apoptosis. The dual-luciferase reporter gene assay revealed miR-23a binding with HDAC2. We found that HDAC2 was poorly expressed in placental tissue samples from PE pregnant women, and its expression correlated inversely with miR-23a expression. HTR-8/SVneo cells showed diminished HDAC2 expression upon miR-23a elevation and increased HDAC2 expression upon miR-23a inhibition. Lentivirus-mediated HDAC2 knockdown mimicked the effects of miR-23a on HTR-8/SVneo cells and led to NF-κB activation. Similarly, HDAC2 overexpression and NF-κB inhibition both abrogated the effects of miR-23a on HTR-8/SVneo cells, suggesting that miR-23a reduced HTR-8/SVneo cell migration and invasion and increased HTR-8/SVneo cell apoptosis by HDAC2 inhibition and NF-κB activation. In summary, these results support a novel role of miR-23b in invasion and apoptosis of trophoblast cells, and imply that targeting miR-23b may be a new avenue for treating PE.

Histone deacetylase 1 and 2 drive differentiation and fusion of progenitor cells in human placental trophoblasts

Cell fusion occurs when several cells combine to form a multinuclear aggregate (syncytium). In human placenta, a syncytialized trophoblast (syncytiotrophoblast) layer forms the primary interface between maternal and fetal tissue, facilitates nutrient and gas exchange, and produces hormones vital for pregnancy. Syncytiotrophoblast development occurs by differentiation of underlying progenitor cells called cytotrophoblasts, which then fuse into the syncytiotrophoblast layer. Differentiation is associated with chromatin remodeling and specific changes in gene expression mediated, at least in part, by histone acetylation. However, the epigenetic regulation of human cytotrophoblast differentiation and fusion is poorly understood. In this study, we found that human syncytiotrophoblast development was associated with deacetylation of multiple core histone residues. Chromatin immunoprecipitation sequencing revealed chromosomal regions that exhibit dynamic alterations in histone H3 acetylation during differentiation. These include regions containing genes classically associated with cytotrophoblast differentiation (TEAD4, TP63, OVOL1, CGB), as well as near genes with novel regulatory roles in trophoblast development and function, such as LHX4 and SYDE1. Prevention of histone deacetylation using both pharmacological and genetic approaches inhibited trophoblast fusion, supporting a critical role of this process for trophoblast differentiation. Finally, we identified the histone deacetylases (HDACs) HDAC1 and HDAC2 as the critical mediators driving cytotrophoblast differentiation. Collectively, these findings provide novel insights into the epigenetic mechanisms underlying trophoblast fusion during human placental development.

Epigenetic Regulation of Multidrug Resistance Protein 1 and Breast Cancer Resistance Protein Transporters by Histone Deacetylase Inhibition

Multidrug resistance protein 1 (MDR1, ABCB1, P-glycoprotein) and breast cancer resistance protein (BCRP, ABCG2) are key efflux transporters that mediate the extrusion of drugs and toxicants in cancer cells and healthy tissues, including the liver, kidneys, and the brain. Altering the expression and activity of MDR1 and BCRP influences the disposition, pharmacodynamics, and toxicity of chemicals, including a number of commonly prescribed medications. Histone acetylation is an epigenetic modification that can regulate gene expression by changing the accessibility of the genome to transcriptional regulators and transcriptional machinery. Recently, studies have suggested that pharmacological inhibition of histone deacetylases (HDACs) modulates the expression and function of MDR1 and BCRP transporters as a result of enhanced histone acetylation. This review addresses the ability of HDAC inhibitors to modulate the expression and the function of MDR1 and BCRP transporters and explores the molecular mechanisms by which HDAC inhibition regulates these transporters. While the majority of studies have focused on histone regulation of MDR1 and BCRP in drug-resistant and drug-sensitive cancer cells, emerging data point to similar responses in nonmalignant cells and tissues. Elucidating epigenetic mechanisms regulating MDR1 and BCRP is important to expand our understanding of the basic biology of these two key transporters and subsequent consequences on chemoresistance as well as tissue exposure and responses to drugs and toxicants. SIGNIFICANCE STATEMENT: Histone deacetylase inhibitors alter the expression of key efflux transporters multidrug resistance protein 1 and breast cancer resistance protein in healthy and malignant cells.

Reciprocal Relationship Between HDAC2 and P-Glycoprotein/MRP-1 and Their Role in Steroid Resistance in Childhood Nephrotic Syndrome

Background: Reduced HDACs levels have been reported in steroid resistant chronic obstructive pulmonary disease and bronchial asthma patients. P-glycoprotein (P-gp) over expression in peripheral blood mononuclear cells (PBMCs) has been reported in patients with steroid resistant nephrotic syndrome (NS). Whether and how HDACs and P-gp are linked with each other is not clear, especially in NS patients. Aim: To evaluate mRNA expression of P-gp/MRP-1 and HDAC2 in PBMCs of steroid sensitive (SSNS) and steroid resistant nephrotic syndrome (SRNS) patients, and determine the relationship between expression of HDAC2 and P-gp/ MRP-1in NS patients. Methods: Twenty subjects (10 in each group), SSNS (mean age 7.54 ± 3.5 years), and SRNS (mean age 8.43 ± 3.8 years) were recruited. mRNA expression of HDAC2 and P-gp/MRP-1 was studied by quantitative real time PCR. PBMCs were treated with Theophylline, 1 μM, and Trichostatin A, 0.8 μM, for 48 h for induction and suppression of HDAC2, respectively. Results: At baseline, expression of P-gp (4.79 ± 0.10 vs. 2.13 ± 0.12, p < 0.0001) and MRP-1 (3.99 ± 0.08 vs. 1.99 ±0.11, p < 0.0001) on PBMCs were increased whereas, HDAC2 mRNA levels (2.97 ± 0.15 vs. 6.02 ± 0.13, p < 0.0001) were significantly decreased in SRNS as compared to that of SSNS patients. Compared to baseline, theophylline reduced mRNA expression of P-gp and MRP-1 (fold change 2.65 and 2.21, ^* p < 0.0001 in SRNS) (fold change 1.25, 1.24, ^* p < 0.0001 in SSNS), respectively. However, it increased the expression of HDAC2 (fold change 5.67, ^* p < 0.0001 in SRNS) (fold change 6.93, ^* p < 0.0001 in SSNS). Compared to baseline, TSA treatment increased mRNA levels of P-gp and MRP-1 (fold change 7.51, 7.31, ^* p < 0.0001 in SRNS) and (fold change 3.49, 3.35, ^* p < 0.0001 in SSNS), respectively. It significantly decreased the level of HDAC2 (fold change 1.50, ^* p < 0.0001 in SRNS) (fold change 2.53, ^* p < 0.0001 in SSNS) patients. Conclusion: Reduced HDAC2 and increased P-gp/MRP-1 activity may play a role in response to steroids in childhood NS. HDAC2 and P-gp/MRP-1 are in reciprocal relationship with each other.

Increased MDR1 Transporter Expression in Human Brain Endothelial Cells Through Enhanced Histone Acetylation and Activation of Aryl Hydrocarbon Receptor Signaling

Multidrug resistance protein 1 (MDR1, ABCB1, P-glycoprotein) is a critical efflux transporter that extrudes chemicals from the blood-brain barrier (BBB) and limits neuronal exposure to xenobiotics. Prior studies in malignant cells demonstrated that MDR1 expression can be altered by inhibition of histone deacetylases (HDAC), enzymes that modify histone structure and influence transcription factor binding to DNA. Here, we sought to identify the mechanisms responsible for the up-regulation of MDR1 by HDAC inhibitors in human BBB cells. Immortalized human brain capillary endothelial (hCMEC/D3) cells were treated with HDAC inhibitors and assessed for MDR1 expression and function. Of the HDAC inhibitors profiled, valproic acid (VPA), apicidin, and suberoylanilide hydroxamic acid (SAHA) increased MDR1 mRNA and protein levels by 30-200%, which corresponded with reduced intracellular accumulation of the MDR1 substrate rhodamine 123. Interestingly, induction of MDR1 mRNA by HDAC inhibitors mirrored increases in the expression of the aryl hydrocarbon receptor (AHR) and its target gene cytochrome P450 1A1. To explore the role of AHR in HDAC inhibitor-mediated regulation of MDR1, a pharmacological activator (β-naphthoflavone, βNF) and inhibitor (CH-223191, CH) of AHR were tested. The induction of MDR1 in cells treated with SAHA was amplified by βNF and attenuated by CH. Furthermore, SAHA increased the binding of acetylated histone H3K9/K14 and AHR proteins to regions of the MDR1 promoter that contain AHR response elements. In conclusion, HDAC inhibitors up-regulate the expression and activity of the MDR1 transporter in human brain endothelial cells by increasing histone acetylation and facilitating AHR binding at the MDR1 promoter.

An update on expression and function of P-gp/ABCB1 and BCRP/ABCG2 in the placenta and fetus

INTRODUCTION

P-glycoprotein (P-gp)/ABCB1 and breast cancer resistance protein (BCRP)/ABCG2 are highly expressed in the placenta and fetus throughout gestation and can modulate exposure and toxicity of drugs and xenobiotics to the vulnerable fetus during the sensitive times of growth and development. We aim to provide an update on current knowledge on placental and fetal expressions of the two transporters in different species, and to provide insight on interpreting transporter expression and fetal exposure relative to the concept of fraction of drug transported. Areas covered: Comprehensive literature review through PubMed (primarily from July 2010 to February 2018) on P-gp and BCRP expression and function in the placenta and fetus of primarily human, mouse, rat, and guinea pig. Expert opinion: While there are many commonalities in the expression and function of P-gp and BCRP in the placenta and fetal tissues across species, there are distinct differences in expression levels and temporal changes. Further studies are needed to quantify protein abundance of these transporters and functionally assess their activities at various gestational stages. Combining the knowledge of interspecies differences and the concept of fraction of drug transported, we may better predict the magnitude of impact these transporters have on fetal drug exposure.