Reciprocal Regulation Between miR-148a/152 and DNA Methyltransferase 1 Is Associated with Hyperhomocysteinemia-Accelerated Atherosclerosis

High paternal homocysteine causes ventricular septal defects in mouse offspring

Maternal hyperhomocysteinemia is widely considered as an independent risk of congenital heart disease (CHD). However, whether high paternal homocysteine causes CHD remains unknown. Here, we showed that increased homocysteine levels of male mice caused decreased sperm count, sperm motility defect and ventricular septal defect of the offspring. Moreover, high levels of paternal homocysteine decrease sperm DNMT3A/3B, accompanied with changes in DNA methylation levels in the promoter regions of CHD-related genes. Folic acid supplement could decrease the occurrence of VSD in high homocysteine male mice. This study reveals that increased paternal homocysteine level increases VSD risk in the offspring, indicating that decreasing paternal homocysteine may be an intervening target of CHD.

The Role of Clonal Hematopoiesis of Indeterminant Potential and DNA (Cytosine-5)-Methyltransferase Dysregulation in Pulmonary Arterial Hypertension and Other Cardiovascular Diseases

DNA methylation is an epigenetic mechanism that regulates gene expression without altering gene sequences in health and disease. DNA methyltransferases (DNMTs) are enzymes responsible for DNA methylation, and their dysregulation is both a pathogenic mechanism of disease and a therapeutic target. DNMTs change gene expression by methylating CpG islands within exonic and intergenic DNA regions, which typically reduces gene transcription. Initially, mutations in the DNMT genes and pathologic DNMT protein expression were found to cause hematologic diseases, like myeloproliferative disease and acute myeloid leukemia, but recently they have been shown to promote cardiovascular diseases, including coronary artery disease and pulmonary hypertension. We reviewed the regulation and functions of DNMTs, with an emphasis on somatic mutations in DNMT3A, a common cause of clonal hematopoiesis of indeterminant potential (CHIP) that may also be involved in the development of pulmonary arterial hypertension (PAH). Accumulation of somatic mutations in DNMT3A and other CHIP genes in hematopoietic cells and cardiovascular tissues creates an inflammatory environment that promotes cardiopulmonary diseases, even in the absence of hematologic disease. This review summarized the current understanding of the roles of DNMTs in maintenance and de novo methylation that contribute to the pathogenesis of cardiovascular diseases, including PAH.

Zinc Improves Semen Parameters in High-Fat Diet-Induced Male Rats by Regulating the Expression of LncRNA in Testis Tissue

This study aimed to identify differentially expressed LncRNAs in testis tissue of male rats induced by high-fat diet and their changes after zinc supplementation, by constructing a high-fat feeding rat model, and then supplemented with zinc, and observed the expression of LncRNA in three groups of normal, high-fat fed, and zinc-intervened rats. Experimental studies show that the semen parameters of male rats with high-fat diet were decreased but recovered after zinc supplementation, and the related LncRNA also changed. Zinc may improve the high-fat diet-induced reduction of semen parameters by changing the expression of related LncRNA.

Epigenetic Regulation by microRNAs in Hyperhomocysteinemia-Accelerated Atherosclerosis

Increased serum levels of homocysteine (Hcy) is a risk factor for cardiovascular disease and is specifically linked to various diseases of the vasculature such as atherosclerosis. However, the precise mechanisms by which Hcy contributes to this condition remain elusive. During the development of atherosclerosis, epigenetic modifications influence gene expression. As such, epigenetic modifications are an adaptive response to endogenous and exogenous factors that lead to altered gene expression by methylation and acetylation reactions of different substrates and the action of noncoding RNA including microRNAs (miRNAs). Epigenetic remodeling modulates cell biology in both physiological and physiopathological conditions. DNA and histone modification have been identified to have a crucial role in the progression of atherosclerosis. However, the potential role of miRNAs in hyperHcy (HHcy)-related atherosclerosis disease remains poorly explored and might be essential as well. There is no review available yet summarizing the contribution of miRNAs to hyperhomocystein-mediated atherogenicity or their potential as therapeutic targets even though their important role has been described in numerous studies. Specifically, downregulation of miR-143 or miR-125b has been shown to regulate VSCMs proliferation in vitro. In preclinical studies, downregulation of miR-92 or miR195-3p has been shown to increase the accumulation of cholesterol in foam cells and increase macrophage inflammation and atherosclerotic plaque formation, respectively. Another preclinical study found that there is a reciprocal regulation between miR-148a/152 and DNMT1 in Hcy-accelerated atherosclerosis. Interestingly, a couple of studies have shown that miR-143 or miR-217 may be used as potential biomarkers in patients with HHcy that may develop atherosclerosis. Moreover, the current review will also update current knowledge on miRNA-based therapies, their challenges, and approaches to deal with Hcy-induced atherosclerosis.

Ischemic Postconditioning Protects against Aged Myocardial Ischemia/Reperfusion Injury by Transcriptional and Epigenetic Regulation of miR-181a-2-3p

Ischemic postconditioning (IPostC) has been proposed as a strategy to mitigate the risk of ischemia/reperfusion (I/R) injury, and autophagy is involved in I/R-induced aged myocardial injury, while the underlying mechanism of IPostC-regulated autophagy is unknown. Here, we implemented miRNA sequencing analysis in aged cardiomyocytes to identify a novel miR-181a-2-3p after HPostC, which inhibits autophagy by targeting AMBRA1 in aged myocardium to protect I/R-induced aged myocardial injury. Mechanistically, we identified that IPostC can induce DNA hypomethylation and H3K14 hyperacetylation of miR-181a-2-3p promoter due to the decreased binding of DNMT3b and HDAC2 at its promoter, which contributes to enhancing the expression of miR-181a-2-3p. More importantly, cooperation of DNMT3b and HDAC2 inhibits the binding of c-Myc at the miR-181a-2-3p promoter in aged cardiomyocytes. In summary, IPostC attenuates I/R-induced aged myocardial injury through upregulating miR-181a-2-3p expression, which is an attribute to transcriptional and epigenetic regulation of its promoter. Our data indicate that miR-181a-2-3p may be a potential therapeutic target against I/R injury in aged myocardium.

Relationship between Coronary VH-IVUS Plaque Characteristics and CTRP9, SAA, and Hcy in Patients with Coronary Heart Disease

Coronary heart disease is a common disease threatening human health. In recent years, the incidence of coronary heart disease in China has only increased. It is the most common type of organ disease caused by coronary atherosclerosis, which is observed in the aorta, carotid artery, and femoral artery. The main clinical treatments for coronary heart disease include coronary artery bypass grafting and drug treatment. To investigate the relationship of serum adipocytokine C1q/tumor necrosis factor-related protein 9 (CTRP9), amyloid A (SAA), and plasma homocysteine (Hcy) with coronary artery plaque characteristics in patients with coronary heart disease. Overall, 143 patients with coronary heart disease admitted to our hospital are selected as research participants. The proportion of plaque necrosis core volume is higher in group A than in group B, and the differences are statistically significant (P < 0.05). In group A, necrotic core volume percentage is negatively correlated with CTRP9 levels and positively correlated with SAA and Hcy levels (P < 0.05). Logistic regression analysis revealed that increased systolic blood pressure, increased number of coronary artery lesions, decreased CTRP9 levels, and increased Hcy levels are independent risk factors for thin fibrous cap atherosclerosis in patients with coronary heart disease (P < 0.05). Decreased CTRP9 levels and increased Hcy levels are independent risk factors for coronary heart disease patients with thin fibrous cap atherosclerosis.

Association of the DNA Methyltransferase and Folate Cycle Enzymes’ Gene Polymorphisms with Coronary Restenosis

Background: In recent years, the interest in genetic predisposition studies for coronary artery disease and restenosis has increased. Studies show that polymorphisms of genes encoding folate cycle and homocysteine metabolism enzymes significantly contribute to atherogenesis and endothelial dysfunction. The purpose of this study was to examine some SNPs of genes coding for folate cycle enzymes and DNA methyltransferases as risk factors for in-stent restenosis. Methods: The study included 113 patients after stent implantation and 62 patients without signs of coronary artery disease at coronary angiography as the control group. Real-time PCR and RFLP-PCR were applied to genotype all participants for MTHFR rs1801133, MTHFR rs1801131, MTR rs1805087, MTRR rs1801394, DNMT1 rs8101626, DNMT3B rs1569686, and DNMT3B rs2424913 gene polymorphisms. Statistical data processing was carried out using the R language and the SPSS Statistics 20 software. Results: Statistically significant differences in the DNMT3B gene polymorphisms were found between patients with and without in-stent restenosis. An association of TT rs1569686 and TT rs2424913 genotypes with the development of restenosis was revealed. The TT rs1569686 genotype was more frequent in the patients under the age of 65 years and in the subgroup of patients with post-12-month restenosis, as was the minor GG genotype for MTR rs1805087. The homozygous TT genotype for MTHFR rs1801133 was significantly more frequent in the subgroup over 65 years old. The frequencies of the heterozygous genotype for the MTRR gene and the minor GG homozygotes for the DNMT1 gene were significantly higher in the subgroup with in-stent restenosis under 65 years old. Conclusions: The results of this study could be used for a comprehensive risk assessment of ISR development, determining the optimal tactics and an individual approach in the treatment of patients with coronary artery disease before or after percutaneous coronary interventions, including homocysteine-lowering treatment in patients with hyperhomocysteinemia and a high risk of in-stent restenosis.

miR-30a-5p promotes glomerular podocyte apoptosis via DNMT1-mediated hypermethylation under hyperhomocysteinemia

Abnormal elevation of homocysteine (Hcy) level is closely related to the development and progression of chronic kidney disease (CKD), with the molecular mechanisms that are not fully elucidated. Given the demonstration that miR-30a-5p is specifically expressed in glomerular podocytes, in the present study we aimed to investigate the role and potential underlying mechanism of miR-30a-5p in glomerular podocyte apoptosis induced by Hcy. We found that elevated Hcy downregulates miR-30a-5p expression in the mice and Hcy-treated podocytes, and miR-30a-5p directly targets the 3'-untranslated region (3'-UTR) of the forkhead box A1 (FOXA1) and overexpression of miR-30a-5p inhibits FOXA1 expression. By nMS-PCR and MassARRAY quantitative methylation analysis, we showed the increased DNA methylation level of miR-30a-5p promoter both and . Meanwhile, dual-luciferase reporter assay showed that the region between --1400 and --921 bp of miR-30a-5p promoter is a possible regulatory element for its transcription. Mechanistic studies indicated that DNA methyltransferase enzyme 1 (DNMT1) is the key regulator of miR-30a-5p, which in turn enhances miR-30a-5p promoter methylation level and thereby inhibits its expression. Taken together, our results revealed that epigenetic modification of miR-30a-5p is involved in glomerular podocyte injury induced by Hcy, providing a diagnostic marker candidate and novel therapeutic target in CKD induced by Hcy.

Interaction Between microRNA and DNA Methylation in Atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease accompanied by complex pathological changes, such as endothelial dysfunction, foam cell formation, and vascular smooth muscle cell proliferation. Many approaches, including regulating AS-related gene expression in the transcriptional or post-transcriptional level, contribute to alleviating AS development. The DNA methylation is a crucial epigenetic modification in regulating cell function by silencing the relative gene expression. The microRNA (miRNA) is a type of noncoding RNA that plays an important role in gene post-transcriptional regulation and disease development. The DNA methylation and the miRNA are important epigenetic factors in AS. However, recent studies have found a mutual regulation between these two factors in AS development. In this study, recent insights into the roles of miRNA and DNA methylation and their interaction in the AS progression are reviewed.

MicroRNA sequences modulating inflammation and lipid accumulation in macrophage “foam” cells: Implications for atherosclerosis

Accumulation of macrophage “foam” cells, laden with cholesterol and cholesteryl ester, within the intima of large arteries, is a hallmark of early “fatty streak” lesions which can progress to complex, multicellular atheromatous plaques, involving lipoproteins from the bloodstream and cells of the innate and adaptive immune response. Sterol accumulation triggers induction of genes encoding proteins mediating the atheroprotective cholesterol efflux pathway. Within the arterial intima, however, this mechanism is overwhelmed, leading to distinct changes in macrophage phenotype and inflammatory status. Over the last decade marked gains have been made in understanding of the epigenetic landscape which influence macrophage function, and in particular the importance of small non-coding micro-RNA (miRNA) sequences in this context. This review identifies some of the miRNA sequences which play a key role in regulating “foam” cell formation and atherogenesis, highlighting sequences involved in cholesterol accumulation, those influencing inflammation in sterol-loaded cells, and novel sequences and pathways which may offer new strategies to influence macrophage function within atherosclerotic lesions.

Downregulation of miR-637 promotes vascular smooth muscle cell proliferation and migration via regulation of insulin-like growth factor-2

Background

Dysregulation of the proliferation and migration of vascular smooth muscle cells (VSMCs) is a crucial cause of atherosclerosis. MiR-637 exerts an antiproliferative effect on multiple human cells. Its impact on atherosclerosis remains largely unexplored.

Methods

Real-time PCR was used to determine miR-637 expression in samples from atherosclerosis patients and animal models. Its expression in VSMC dysfunction models (induced by ox-LDL) was also measured. The proliferation and migration of VSMCs were respectively tested using CCK-8 and Transwell assays, and apoptosis was measured using flow cytometry. The Targetscan database was used to predict the target genes of miR-637. Interaction between miR-637 and the potential target gene was validated via real-time PCR, western blotting and a luciferase reporter assay.

Results

MiR-637 expression was significantly lower in atherosclerosis patient and animal model samples. It also decreased in a dose- and time-dependent manner in animal models with ox-LDL-induced atherosclerosis. Transfection with miR-637 mimics suppressed the proliferation and migration of VSMCs while promoting apoptosis, while transfection with miR-637 inhibitors had the opposite effects. We also validated that insulin-like growth factor-2 (IGF-2), a crucial factor in the pathogenesis of atherosclerosis, serves as a target gene for miR-637.

Conclusion

MiR-637 targeting IGF-2 contributes to atherosclerosis inhibition and could be a potential target for this disease.

Homocysteine accelerates atherosclerosis by inhibiting scavenger receptor class B member1 via DNMT3b/SP1 pathway

Homocysteine (Hcy) is an independent risk factor for atherosclerosis, which is characterized by lipid accumulation in the atherosclerotic plaque. Increasing evidence supports that as the main receptor of high-density lipoprotein, scavenger receptor class B member 1 (SCARB1) is protective against atherosclerosis. However, the underlying mechanism regarding it in Hcy-mediated atherosclerosis remains unclear. Here, we found the remarkable inhibition of SCARB1 expression in atherosclerotic plaque and Hcy-treated foam cells, whereas overexpression of SCARB1 can suppress lipid accumulation in foam cells following Hcy treatment. Analysis of SCARB1 promoter showed that no significant change of methylation level was observed both in vivo and in vitro under Hcy treatment. Moreover, it was found that the negative regulation of DNMT3b on SCARB1 was due to the decreased recruitment of SP1 to SCARB1 promoter. Thus, we concluded that inhibition of SCARB1 expression induced by DNMT3b at least partly accelerated Hcy-mediated atherosclerosis through promoting lipid accumulation in foam cells, which was attributed to the decreased binding of SP1 to SCARB1 promoter. In our point, these findings will provide novel insight into an epigenetic mechanism for atherosclerosis.

Dysregulation of Epigenetic Mechanisms of Gene Expression in the Pathologies of Hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) exerts a wide range of biological effects and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Although mechanisms of HHcy toxicity are not fully uncovered, there has been a significant progress in their understanding. The picture emerging from the studies of homocysteine (Hcy) metabolism and pathophysiology is a complex one, as Hcy and its metabolites affect biomolecules and processes in a tissue- and sex-specific manner. Because of their connection to one carbon metabolism and editing mechanisms in protein biosynthesis, Hcy and its metabolites impair epigenetic control of gene expression mediated by DNA methylation, histone modifications, and non-coding RNA, which underlies the pathology of human disease. In this review we summarize the recent evidence showing that epigenetic dysregulation of gene expression, mediated by changes in DNA methylation and histone N-homocysteinylation, is a pathogenic consequence of HHcy in many human diseases. These findings provide new insights into the mechanisms of human disease induced by Hcy and its metabolites, and suggest therapeutic targets for the prevention and/or treatment.

MicroRNA-148a-3p promotes survival and migration of endothelial cells isolated from Apoe deficient mice through restricting circular RNA 0003575

The incidence of atherosclerosis is greatly increased, which becomes the leading cause for the death and disability worldwide. Endothelial cells dysfunction plays a substantial role in the pathogenesis of atherosclerosis. MicroRNA-148a-3p (miR-148a-3p) and circular RNA 0003575 (circ_0003575) modulated lipid metabolism and proliferative function of endothelial cells, respectively. However, the role of them in modulation of endothelial cell function and progression of atherosclerosis remains unknown. Endothelial cells were isolated from the aorta of Apoe^-/- mice. miR-148a-3p in atherosclerosis patients and healthy controls were measured by qRT-PCR. Overexpression and knockdown of miR-148a-3p in endothelial cells were established. The proliferation, migration and apoptosis of endothelial cells were measured by MTT, Transwell, and fluorescence microscope, respectively. Online software (miRWalk 2.0 and RegRNA2.0) and databases (miRWalk, miRanda, RNA22, and Targetscan) were used to predict potential target genes of miR-148a-3p and circ_0003575. The expression of target genes was detected through western blotting. The expression of miR-148a-3p was significantly upregulated in patients with atherosclerosis as relative to healthy people. Overexpression of miR-148a-3p exhibited stimulatory effects on endothelial cell proliferation and migration and inhibited programmed cell death. Six intersection target genes, c-MAF, FOXO4, FOXO3, MITF, ETV7, and CRX, were predicted between miR-148a-3p and circ_0003575. The opposite effects of circ_0003575 and miR-148a-3p on the expression of FOXO4 and FOXO3, which are essential for lipid metabolism. We demonstrate that miR-148a-3p suppresses FOXO4 and FOXO3 expression via interruption of circ_0003575 function, which in turn impairs the proliferative and migratory function of endothelial cells, eventually exacerbating the atherosclerosis.

Promising Directions in Atherosclerosis Treatment Based on Epigenetic Regulation Using MicroRNAs and Long Noncoding RNAs

Atherosclerosis is one of the leading causes of mortality from cardiovascular disease (CVD) and is a chronic inflammatory disease of the middle and large arteries caused by a disruption of lipid metabolism. Noncoding RNA (ncRNA), including microRNA (miRNA), small interfering RNA (siRNA) and long noncoding RNA (lncRNA), was investigated for the treatment of atherosclerosis. Regulation of the expression of noncoding RNA targets the constituent element of the pathogenesis of atherosclerosis. Currently, miRNA therapy commonly employs miRNA antagonists and mimic compounds. In this review, attention is focused on approaches to correcting molecular disorders based on the genetic regulation of the transcription of key genes responsible for the development of atherosclerosis. Promising technologies were considered for the treatment of atherosclerosis, and examples are given for technologies that have been shown to be effective in clinical trials.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

Polyamine Metabolism and Gene Methylation in Conjunction with One-Carbon Metabolism

Recent investigations have revealed that changes in DNA methylation status play an important role in aging-associated pathologies and lifespan. The methylation of DNA is regulated by DNA methyltransferases (DNMT1, DNMT3a, and DNMT3b) in the presence of S-adenosylmethionine (SAM), which serves as a methyl group donor. Increased availability of SAM enhances DNMT activity, while its metabolites, S-adenosyl-l-homocysteine (SAH) and decarboxylated S-adenosylmethionine (dcSAM), act to inhibit DNMT activity. SAH, which is converted from SAM by adding a methyl group to cytosine residues in DNA, is an intermediate precursor of homocysteine. dcSAM, converted from SAM by the enzymatic activity of adenosylmethionine decarboxylase, provides an aminopropyl group to synthesize the polyamines spermine and spermidine. Increased homocysteine levels are a significant risk factor for the development of a wide range of conditions, including cardiovascular diseases. However, successful homocysteine-lowering treatment by vitamins (B6, B12, and folate) failed to improve these conditions. Long-term increased polyamine intake elevated blood spermine levels and inhibited aging-associated pathologies in mice and humans. Spermine reversed changes (increased dcSAM, decreased DNMT activity, aberrant DNA methylation, and proinflammatory status) induced by the inhibition of ornithine decarboxylase. The relation between polyamine metabolism, one-carbon metabolism, DNA methylation, and the biological mechanism of spermine-induced lifespan extension is discussed.

H19 knockdown suppresses proliferation and induces apoptosis by regulating miR-148b/WNT/β-catenin in ox-LDL -stimulated vascular smooth muscle cells

Background

Long non-coding RNAs (lncRNAs) have been identified as critical regulators in the development of atherosclerosis (AS). Here, we focused on discussing roles and molecular mechanisms of lncRNA H19 in vascular smooth muscle cells (VSMCs) progression.

Methods

RT-qPCR assay was used to detect the expression patterns of H19 and miR-148b in clinical samples and cells. Cell proliferative ability was evaluated by CCK-8 and colony formation assays. Cell apoptotic capacity was assessed by apoptotic cell percentage and the caspase-3 activity. Bioinformatics analysis, luciferase and RNA immunoprecipitation (RIP) assays were employed to demonstrate cell percentage and the relationship among H19, miR-148b and wnt family member 1 (WNT1). Western blot assay was performed to determine expressions of proliferating cell nuclear antigen (PCNA), ki-67, Bax, Bcl-2, WNT1, β-catenin, C-myc and E-cadherin.

Results

The level of H19 was increased and miR-148b expression was decreased in human AS patient serums and oxidized low-density lipoprotein (ox-LDL)-stimulated human aorta vascular smooth muscle cells (HA-VSMCs). H19 knockdown suppressed proliferation and promoted apoptosis in HA-VSMCs following the treatment of ox-LDL. H19 inhibited miR-148b expression by direct interaction. Moreover, miR-148b inhibitor could reverse the effects of H19 depletion on proliferation and apoptosis in ox-LDL-stimulated HA-VSMCs. Further mechanical explorations showed that WNT1 was a target of miR-148b and H19 acted as a competing endogenous RNA (ceRNA) of miR-148b to enhance WNT1 expression. Furthermore, miR-148 inhibitor exerted its pro-proliferation and anti-apoptosis effects through activating WNT/β-catenin signaling in ox-LDL-stimulated HA-VSMCs.

Conclusion

H19 facilitated proliferation and inhibited apoptosis through modulating WNT/β-catenin signaling pathway via miR-148b in ox-LDL-stimulated HA-VSMCs, implicating the potential values of H19 in AS therapy.

Magnetic immunoassay using CdSe/ZnS quantum dots as fluorescent probes to detect the level of DNA methyltransferase 1 in human serum sample

Background

DNA methyltransferase 1 (DNMT1), a dominant enzyme responsible for the transfer of a methyl group from the universal methyl donor to the 5-position of cytosine residues in DNA, is essential for mammalian development and closely related to cancer and a variety of age-related chronic diseases. DNMT1 has become a useful biomarker in early disease diagnosis and a potential therapeutic target in cancer therapy and drug development. However, till now, most of the studies on DNA methyltransferase (MTase) detection have focused on the prokaryote MTase and its activity.

Methods

A magnetic fluorescence-linked immunosorbent assay (FLISA) using CdSe/ZnS quantum dots as fluorescent probes was proposed for the rapid and sensitive detection of the DNMT1 level in this study. Key factors that affect the precision and accuracy of the determination of DNMT1 were optimized.

Results

Under the optimal conditions, the limit of detection was 0.1 ng/mL, the linear range was 0.1-1,500 ng/mL, the recovery was 91.67%-106.50%, and the relative standard deviations of intra- and inter-assays were respectively 5.45%-11.29% and 7.03%-11.25%. The cross-reactivity rates with DNA methyltransferases 3a and 3b were only 4.0% and 9.4%, respectively. Furthermore, FLISA was successfully used to detect the levels of DNMT1 in human serum samples, and compared with commercial enzyme-linked immunosorbent assay (ELISA) kits. The results revealed that there was a good correlation between FLISA and commercial ELISA kits (correlation coefficient r=0.866, p=0.001). The linear scope of FLISA was broader than ELISA, and the measurement time was much shorter than ELISA kits.

Conclusion

These indicated that the proposed FLISA method was sensitive and high throughput and can quickly screen the level of DNMT1 in serum samples.