CN114317722A - Application of lncRNA APAT molecule in atherosclerotic heart disease - Google Patents

Abstract

The invention discloses a biomarker lncRNA APAT related to macrophage inflammatory reaction, atherosclerotic heart disease and atherosclerotic plaque stability; the invention discloses the use of lncRNA APAT and inhibitors thereof in the preparation of products for assessing atherosclerotic plaque stability and treating atherosclerotic heart disease; the invention discloses an mPCSK9 atherosclerosis mouse model for specifically expressing lncRNA APAT by monocytes, which is used for preparing a research model of pathogenesis of atherosclerotic heart disease. The lncRNA APAT can be used for evaluating and diagnosing the early stage of the occurrence of the coronary atherosclerotic heart disease or evaluating and predicting the stability and the progress of the atherosclerotic plaque, and provides a treatment target and an important basis for clinical application of gene therapy, drug therapy and the like.

Description

Application of lncRNA APAT molecule in atherosclerotic heart disease

Technical Field

The invention relates to the technical fields of inspection medicine, clinical medicine and biology, in particular to application of lncRNA APAT molecules in atherosclerotic heart disease.

Background

Cardiovascular and cerebrovascular diseases are the first killers of the residents in China, the number of the sick people reaches 2.9 hundred million, and the first death rate is the first death rate. Atherosclerosis is an important pathological basis for the occurrence and development of cardiovascular and cerebrovascular diseases, monocytes in circulating blood migrate and adhere to activated vascular endothelial cells, infiltrate to the intimal lower layer to form macrophages, which are the initial link of atherosclerosis, and the monocytes-macrophages regulate and control various stages of atherosclerosis development through mechanisms such as phenotypic transformation, inflammatory factor secretion and the like. Macrophages have phenotypic heterogeneity and plasticity, largely divided into two types: classical activated macrophages (M1), and alternative activated macrophages (M2). Macrophages of type M1 are abundant in plaques and promote the progression of atherosclerosis by secreting inflammatory factors; in contrast, macrophages of type M2 may exert a plaque progression inhibiting effect by secreting anti-inflammatory factors. The stability of the plaque determines the risk of atherosclerosis. The stable plaque fibrous cap is thick and not easily ruptured. The mixed vulnerable plaque is covered by a thin and unstable fibrous cap with a large lipid core, which is prone to rupture, leading to thrombosis and inducing acute cardiovascular and cerebrovascular events such as acute myocardial infarction, stroke, etc. Therefore, exploring the mechanism and molecular markers of plaque stability is the key to early prevention and treatment of cardiovascular and cerebrovascular events. Genetic, epigenetic and environmental factors are commonly involved in the development process of atherosclerosis.

Long-chain non-coding RNAs (lncRNAs for short) are nucleotide sequences which have the length of more than 200 bases and no protein coding potential, regulate gene expression at multiple levels such as epigenetic inheritance, transcription and post-transcription levels and play an important role in biological processes such as cell proliferation, differentiation, apoptosis and the like. Generally, nuclear-localized lncRNAs can be involved in chromatin remodeling through regulatory histone modification; cytoplasmic-localized lncRNAs serve as competitive endogenous RNA molecules to regulate gene expression. The role of LncRNA in atherosclerosis is of great concern.

The invention firstly identifies the specific high expression of an lncRNA molecule in peripheral blood of coronary heart disease patients with mixed vulnerable plaques by a whole transcriptome sequencing technology. The lncRNA molecule is located on the human chromosome 12, and the ID number in the Ensembl database is ENST00000545163.2 and is 686bp in length. The inventors named it lncRNA APAT. The role of lncRNA APAT in atherosclerosis and its related heart disease has not been reported.

Disclosure of Invention

In order to solve the problems, the invention aims to provide an lncRNA APAT (long nuclear RNA apoptosis inhibitor) which is a biomarker related to the stability of atherosclerotic heart disease and atherosclerotic plaques and application thereof in diagnostic and therapeutic products.

In order to achieve the purpose, the invention adopts the following technical scheme:

the inventor firstly identifies the specific high expression of an lncRNA APAT molecule in peripheral blood of coronary heart disease patients with mixed vulnerable plaques by a whole transcriptome sequencing technology, and further discovers that the lncRNA APAT molecule plays an important role in regulating and controlling the activity of mononuclear-macrophages and influencing the instability of plaques through a gene function experiment. The lncRNA APAT in the application is a novel lncRNA molecule discovered by carrying out whole-transcriptome sequencing identification on patients with coronary mixed vulnerable plaque groups, and no functional annotation and relevant research report exist at present.

Based on the above, the first aspect of the invention provides an application of a reagent for detecting the expression level of lncRNA APAT, wherein the nucleotide sequence of lncRNA APAT is shown as SEQ ID NO.1, in the preparation of a product for diagnosing atherosclerotic heart disease.

Further, the lncRNA APAT is highly expressed in peripheral blood of coronary heart disease patients with coronary atherosclerotic mixed vulnerable plaque.

Further, the lncRNA APAT can promote monocyte-macrophage inflammation and lipid phagocytosis; inhibiting the cholesterol efflux capacity of monocyte-macrophages; promoting the number and area of atherosclerotic plaque formation.

In a third aspect, the invention provides a kit for early diagnosis of atherosclerotic heart disease or prediction of atherosclerotic plaque stability and progression, said kit comprising means for detecting the expression level of lncRNA APAT, and instructions for use of said kit; the lncRNA APAT nucleotide sequence is shown in SEQ ID NO. 1.

Further, the tool comprises a primer pair for specifically detecting the expression level of IncRNA APAT, and the sequences of the primer pair are shown as SEQ ID NO.2 and SEQ ID NO. 3.

The fourth aspect of the invention provides a lncRNA APAT inhibitor, wherein the lncRNA APAT nucleotide sequence is shown in SEQ ID NO. 1; the inhibitor comprises an agent that inhibits lncRNA APAT expression.

Further, the agent for inhibiting the expression of lncRNA APAT comprises antisense oligonucleotide (ASO) and/or small interfering RNA (siRNA).

Further, the antisense oligonucleotide is selected from at least one of the nucleotide sequences shown in SEQ ID NO. 6-8.

Further, the small interfering RNA is selected from at least one of the nucleotide sequences shown in SEQ ID NO. 9-11.

Preferably, the inhibitor comprises a nucleotide sequence of antisense oligonucleotide shown as SEQ ID NO.6-8 and a nucleotide sequence of small interfering RNA shown as SEQ ID NO. 9-11.

In a fifth aspect, the invention provides the use of the inhibitor in the preparation of a pharmaceutical composition for the prevention or treatment of atherosclerotic heart disease.

Further, the inhibitor has effects of inhibiting inflammation of monocyte-macrophage and lipid phagocytosis, and promoting cholesterol efflux ability of monocyte-macrophage; preferably, the genes related to the inflammatory factors of macrophages include monocyte chemotactic factor 1 (MCP 1), tumor necrosis factor alpha (tumor necrosis factor alpha, TNF α), vascular cell adhesion molecule 1(vascular cell adhesion molecule 1, VCAM1), interleukin (interleukin, IL)1 β (IL1 β) and interleukin 6(IL 6).

The sixth aspect of the invention provides application of mPCSK9 atherosclerosis mouse model with monocyte specific expression of lncRNA APAT in preparation of research model of pathogenesis of atherosclerotic heart disease or screening model of drugs for treating atherosclerotic heart disease, wherein the mouse model is homozygote mouse (APAT) with monocyte-macrophage specific expression of lncRNA APAT and provided with mPCSK9 to induce formation of atherosclerosis^floxed/^floxed，Lyz2-Cre)。

Based on the technical scheme, the invention has the following beneficial effects:

the invention provides a biomarker lncRNA APAT related to atherosclerotic heart disease and atherosclerotic plaque stability, and confirms that the lncRNA APAT is highly expressed in peripheral blood of coronary heart disease patients with atherosclerotic mixed vulnerable plaque; the invention provides the use of lncRNA APAT in the manufacture of a product for assessing atherosclerotic plaque stability and risk of atherosclerotic heart disease development in an individual; the invention also provides an mPCSK9 atherosclerosis mouse model of the monocyte specific expression lncRNA APAT, which is applied to the preparation of a research model of pathogenesis of atherosclerotic heart disease or a screening model of drugs for treating atherosclerotic heart disease, wherein the mouse model is a homozygote mouse (APAT) of the monocyte-macrophage specific expression lncRNA APAT and the mPCSK9 is given to induce atherosclerosis^floxed/^floxedLyz 2-Cre). The APAT can be used for evaluating and diagnosing the early stage of the occurrence of the atherosclerotic heart disease or evaluating and predicting the stability and the progress of the atherosclerotic plaque, has important significance for the early treatment of the atherosclerotic heart disease and the saving of medical cost, and provides a treatment target and an important basis for clinical application of gene therapy, drug therapy and the like.

Drawings

FIG. 1 IncRNA APAT is highly expressed in peripheral blood of patients with coronary heart disease with atherosclerotic mixed vulnerable plaques. A. Identifying peripheral blood lncRNA molecules related to atherosclerosis mixed vulnerable plaques by adopting a whole transcriptome sequencing technology, wherein the lncRNA molecules indicated by arrows are lncRNA APAT; B. the high expression of lncRNA APAT in the peripheral blood of a coronary heart disease patient with atherosclerosis mixed vulnerable plaque is verified by a real-time fluorescent quantitative PCR method. The number n of the control group is 10, and the number n of the mixed vulnerable plaque patients is 5. P < 0.01.

FIG. 2 shows the expression level profile of lncRNA APAT molecules in human peripheral blood cells detected by real-time fluorescent quantitative PCR. In the figure, CD3⁺: human peripheral blood T lymphocytes (n ═ 10); CD14⁺: b lymphocytes (n-4); CD19⁺: peripheral blood mononuclear cells (n ═ 8); NK: natural killer cells (n ═ 6). P<0.01。

FIG. 3 is a real-time fluorescent quantitative PCR method for detecting the expression level of IncRNA APAT in different phenotypes of monocyte-macrophages. M0: unstimulated activated macrophages; m1: classical activated macrophages (pro-inflammatory subtypes); m2: replacement of activated macrophages (anti-inflammatory subtype). n is 5. P < 0.05.

FIG. 4 IncRNA APAT promotes the expression of inflammatory factors in monocyte-macrophages. Lncrna APAT promotes mRNA expression levels of the monocyte-macrophage inflammatory factors ICAM1, TNF α, MCP 1. In the figure, Lv-NC is a control group, and Lv-APAT is an overexpression lncRNA APAT group; inhibitory effect of lncrna APAT inhibitors on mRNA expression levels of monocyte-macrophage inflammatory factors ICAM1, TNF α, MCP 1. In the figure, NC is a control group, and Silencer-APAT is a lncRNA APAT inhibitor group (antisense oligonucleotide + small interfering RNA). n is 5. P <0.05, P < 0.01.

FIG. 5 promotion of lncRNA APAT on monocyte-macrophage adhesion. Lncrna APAT promotes the adhesion capacity of monocytes-macrophages. In the figure, Lv-NC is a control group, and Lv-APAT is an overexpression lncRNA APAT group; IncRNA APAT inhibitor inhibition of monocyte-macrophage adhesion function, NC in the figure is control group, Silene-APAT is IncRNA APAT inhibitor group (antisense oligonucleotide + small interfering RNA). n is 5. Scale bar: 200 μm. P <0.05, P < 0.001.

Figure 6 lncRNA APAT promotes lipid phagocytic capacity of monocyte-macrophages. Lncrna APAT promotes mRNA expression levels of monocyte-macrophage lipid phagocytic genes SR-a1 and CD 36; lncRNA APAT on monocyte-macrophage lipid phagocytic ability. In the figure, Lv-NC is a control group, and Lv-APAT is an overexpression lncRNA APAT group; NC is a control group, Silencer-APAT is a lncRNA APAT inhibitor group (antisense oligonucleotide + small interfering RNA). n is 5. Scale bar: 50 μm. P <0.05, P < 0.01.

FIG. 7.lncRNA APAT inhibits the cholesterol efflux capacity of monocyte-macrophages. lncRNA APAT inhibits the mRNA expression levels of the cholesterol efflux genes ABCG1 and AR-B1 of monocytes-macrophages; lncrna APAT inhibitors promote mRNA expression levels of the cholesterol efflux genes ABCG1 and AR-B1 of monocytes-macrophages; lncrna APAT inhibitors promote the cholesterol efflux capacity of monocytes-macrophages. In the figure, Lv NC is a control group, and Lv-APAT is an overexpression lncRNA APAT group; NC is a control group, Silencer-APAT is a lncRNA APAT inhibitor group (antisense oligonucleotide + small interfering RNA). n is 5. P <0.05, P < 0.01.

FIG. 8 lncRNA APAT promotes plaque progression in the aortic region of atherosclerosis in mice. A. Detecting atherosclerotic plaque conditions of aorta parts of mouse models of a control group and an experimental group by adopting an oil red O staining method; B. comparing the atherosclerotic plaque area of the aortic region of the control group and experimental group mouse models; C. comparing the areas of atherosclerotic plaques of different parts of aorta of the mouse models of the control group and the experimental group, including aortic arch part, thoracic aorta and abdominal aorta. Grouping experiments: the control group and the experimental group are atherosclerosis mouse models of mononuclear-macrophage specific expression lncRNA APAT. n is 10. P <0.05, P < 0.01.

FIG. 9 lncRNA APAT promotes the progression of atherosclerotic plaques in mice. A. Detecting the morphological change of atherosclerotic plaques at the thoracic aorta parts of the mouse models of the control group and the experimental group by adopting a hematoxylin-eosin staining method; B. comparing the areas of atherosclerotic plaques at the thoracic aorta of the control group mouse model and the experimental group mouse model. n is 6. P <0.05, P < 0.01.

FIG. 10 shows the real-time fluorescent quantitative PCR method for detecting the inflammatory factor expression level of peripheral blood mononuclear cells of an atherosclerosis mouse model. IL6 in the figure: interleukin 6; TNF α, tumor necrosis factor α; LOX 1: lectin-like oxidized low density lipoprotein receptor. Grouping experiments: the control group and the experimental group are atherosclerosis mouse models of mononuclear-macrophage specific expression lncRNA APAT. n is 6. P <0.05, P < 0.01.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The invention firstly identifies the specific high expression of the lncRNA APAT molecule in the peripheral blood of the coronary heart disease patient with mixed vulnerable plaque through the whole transcriptome sequencing technology, and further discovers that the lncRNA APAT molecule plays an important role in regulating and controlling the activity of mononuclear-macrophage and influencing the instability of plaque through a gene function experiment. The ID number of the lncRNA APAT in an Ensembl database is ENST00000545163.2, the length is 686bp, and the nucleotide sequence is shown as SEQ ID NO. 1.

The statistical method used in the invention is as follows:

quantitative variables are expressed as means ± standard error and categorical variables are expressed as percentages. The χ 2 test was used to compare qualitative variables and the differences between groups for quantitative variables were calculated using Student's t test or One-way ANOVA. Data analysis Using SPSS Statistics 20.0(SPSS Inc, Chicago, USA), P <0.05 is statistically significant for the differences.

Example 1 lncRNA APAT is specifically high expressed in peripheral blood of patients with mixed vulnerable plaques

1. Study subjects: the research object is from patients suspected of coronary artery angiography examination (CCTA) of coronary heart disease in Fuweisan Hospital of Chinese medical science institute, the age is more than or equal to 45 years, and patients with blood diseases, peptic ulcer, liver and kidney insufficiency, infection, autoimmune diseases and tumor are excluded. Coronary scans were performed using 64-row helical CT and coronary images were analyzed separately by two radiologists. From coronary CT angiography images, the study subjects were divided into 2 groups, including JianHealthy control group (n ═ 10) and group of mixed vulnerable plaques (n ═ 5). Definition of hybrid vulnerable plaque: is obviously different from coronary vessel cavity and is more than 1mm²Is judged as an atherosclerotic plaque, which contains lipid, fibrous, calcified components and the like. Coronary artery with diameter no more than 1mm²Plaque patients were control groups.

Peripheral blood samples were obtained from fasting blood draws from the morning. The ethical committee of the hospital, Fuweichi, Chinese medical sciences approved the design of the study and the use of human peripheral blood, and all patients signed written informed consent.

2. Peripheral blood whole transcriptome sequencing: using Tempus^TM2-3 ml of peripheral Blood of a patient is collected by a Blood RNA Tube, immediately and acutely shaken for 15-30 seconds, fully and uniformly mixed, and then Tempus is used^TMThe Spin RNA Isolation Kit (#4380204, Invitrogen, Carlsbad, Calif., USA) extracts total RNA, stored at-80 ℃ for whole transcriptome sequencing assays. Use of

The Stranded Total RNA Sample Preparation kit (#15031048, Illumina, San Diego, California, USA) constructs a library and performs whole transcriptome sequencing by HiSeq X-ten sequencer (Illumina, San Diego, California, USA). Differentially expressed genes in the sequencing results were analyzed using the edgeR algorithm, with the following screening criteria: the False Discovery Rate (FDR) is less than or equal to 0.01, the fold-change (fold-change) is more than or equal to 2, and the number of fragments of each thousand bases of the exon aligned in each 1 million aligned Fragments (FPKM) is more than or equal to 1.

3. Verifying the sequencing result of the whole transcriptome by adopting a real-time fluorescent quantitative PCR method: peripheral blood total RNA was reverse transcribed into cDNA using PrimeScript RT reagent Kit with gDNA Eraser (# RR047A, Takara, Dalian, China), a reaction System was configured using SYBR Green qpCR Mix (#11202ES08, YEASEN, Shanghai, China) reagent, and the expression level of lncRNA APAT was detected by placing the reaction System in ABI 7500System (Applied Biosystems, Foster City, CA, USA). Relative expression level of lncRNA APAT was calculated by the Δ Δ Ct method using GAPDH as an internal reference.

The primer sequence for specifically amplifying lncRNA APAT is as follows:

Forward 5'-GACCACCGCCAACAGAAG-3'，SEQ ID NO.2；

Reverse 5'-TGACAAAAGCCATAGCATGAA-3'，SEQ ID NO.3。

the amplification GAPDH primer sequences are as follows:

Forward 5'-GAAGGTGAAGGTCGGAGTCA-3'，SEQ ID NO.4；

Reverse 5'-GGAAGATGGTGATGGGATTTC-3'，SEQ ID NO.5。

the results show that: using whole transcriptome sequencing technology, lncRNA APAT was found to be highly expressed in peripheral blood of coronary heart disease patients with atherosclerotic mixed vulnerable plaques compared to healthy controls without coronary plaques (FIG. 1A). The real-time fluorescent quantitative PCR method is adopted to further verify the sequencing result, and the expression level of lncRNA APAT in the peripheral blood of the patients in the mixed vulnerable plaque group is obviously increased and is 1.9 times that of the healthy control group without plaque (P is less than 0.01; figure 1B).

Example 2 expression levels of lncRNA APAT in human peripheral blood cells

To further study the expression profile of lncRNA APAT in peripheral blood cells, the present invention first extracts mononuclear cells from healthy human peripheral blood by differential centrifugation, and then classifies the mononuclear cells into CD3 by magnetic bead method⁺(human peripheral blood T lymphocytes), CD14⁺(B lymphocytes), CD19⁺(peripheral blood mononuclear cells) and NK cells (natural killer cells). And detecting the expression level of lncRNA APAT in the mononuclear cells of the human peripheral blood by adopting a real-time fluorescent quantitative PCR method.

The differential centrifugation method is used for extracting human peripheral blood mononuclear cells:

4ML of fresh peripheral blood anticoagulated with heparin is centrifuged at 1500rpm for 10min at room temperature, the supernatant is discarded, the solution is diluted by adding PBS buffer solution, the final volume is 4ML, the solution is fully mixed and slowly superposed in a 15ML tube in which 4ML of lymph extraction (Cat #10771-500ML, Sigma-Aldrich, Saint Louis, MO, USA) solution is added in advance along the tube wall by using a dropper. Centrifuge at 1500rpm for 40min at room temperature. And (3) putting the mist liquid of the middle layer into a new 15ml tube, adding 6 times of volume of PBS for dilution, centrifuging at 1700rpm at room temperature for 10min, and washing twice.

Magnetic bead method for separating CD3⁺，CD14⁺，CD19⁺And NK cells:

transfer 200. mu.l of Robose p buffer (Cat #20164, STEMCELL Technologies, Vancouver, British Columbia, Canada) from human peripheral blood mononuclear cells to a 5ml flow tube, add 20. mu.l of cocktail CD3⁺Mixing the antibody, standing at room temperature for 10min, adding 20 μ l magnetic beads, mixing, standing at room temperature for 5min, adding R buffer, the final volume is 2.5ml, mixing, standing at room temperature for 3min in magnetic pole, keeping the flow tube from separating from the magnetic pole, pouring the liquid in the tube into 15ml tube, taking down the flow tube, adding 2.5ml Robosep buffer, washing twice, re-suspending the cells in the flow tube with 100 μ l Robosep buffer, transferring into 1.5ml tube, 5min at 4000rpm, discarding the supernatant, adding 500 μ l trizol (Cat. #15596 Buchner 026, Invitrogen, Carlsbad, CA, USA), and marking as CD3⁺A cell.

Isolation of CD14 from mononuclear cells by the same method⁺And CD19⁺Positive cells and antibody are respectively cocktail CD14⁺Antibody and cocktail CD19⁺An antibody. The final remaining cells were labeled as NK cells.

The CD3 is detected by real-time fluorescent quantitative PCR method⁺，CD14⁺，CD19⁺And the expression level of lncRNA APAT in NK cells. The real-time fluorescent quantitative PCR method was as described in example 1.

The results show that: IncRNA APAT is mainly CD3⁺High expression in the cells (FIG. 2).

Example 3 expression levels of lncRNA APAT on different phenotypes of Mono-macrophages

Furthermore, a monocyte-macrophage polarization model is established, and the expression level of lncRNA APAT in monocyte-macrophages with different phenotypes is clarified.

The specific method for establishing the monocyte-macrophage polarization model comprises the following steps: human monocytic Line THP-1 cells (China Infrastructure of Cell Line Resources, Beijing, China) were cultured in RPMI Medium Modified Medium (HyClone, Logan, UT, USA) containing 10% Fetal Bovine Serum (FBS). THP-1 cells differentiated into M0-type macrophages after stimulation with 100ng/ml phorbol ester (phorbol-12-myrsate-13-acetate, PMA) (# P1585, Sigma-Aldrich, Saint Louis, MO, USA) for 48 hours. M0 type cells were stimulated to differentiate into M1 type macrophages for 24 hours with 1ng/ml Lipopolysaccharide (LPS) (# L3012, Sigma-Aldrich, Saint Louis, MO, USA) and 20ng/ml interferon γ (interferon- γ) (#300-02, PeproTech, Rocky Hill, NJ, USA); m0-type macrophages were stimulated with 20ng/ml IL4(#200-04, PeproTech, Rocky Hill, NJ, USA) for 24 hours to differentiate into M2-type macrophages.

The real-time quantitative PCR method is adopted to detect the expression level of lncRNA APAT in M0, M1 and M2 type mononuclear-macrophages.

The results show that: during macrophage polarization, lncRNA APAT was expressed at 30% higher levels in M1-type macrophages compared to M0 macrophages (P < 0.05; FIG. 3).

Example 4 Effect of lncRNA APAT and inhibitors thereof in the monocyte-macrophage inflammatory response

Use of lncRNA APAT in the treatment of inflammatory reaction of monocytes-macrophages

Constructing a mononuclear-macrophage line over-expressing lncRNA APAT: mixing THP-1 monocyte-macrophage at 1 × 10⁵One/well density was inoculated into 12-well plates, infected with lncRNA APAT recombinant lentiviral vector (lv-APAT) (Cat #42609-11, GeneCopoeia, Guingzhou, China), cultured for 4 days, and after Flow-through (FACS Aria 2Flow Cytometry/Cell Sorting System, BD Biosciences, San Jose, Calif., USA), lv-APAT positive cells (expressing green fluorescent protein-tagged EGFP) were screened. The positive cells after selection were cultured for 1 week.

Detecting the mRNA expression level of the inflammatory factor by adopting a real-time fluorescent quantitative PCR method: total cellular RNA was extracted by TRIzol method, total RNA was reverse transcribed into cDNA using PrimeScript RT reagent Kit with gDNA Eraser (# RR047A, Takara, Dalian, China) Kit, a reaction System was configured using SYBR Green qPCR Mix (#11202ES08, YEASEN, Shanghai, China) reagent, placed in ABI 7500System (Applied Biosystems, Foster City, CA, USA), and mRNA expression level of inflammatory factor in over-expressed lv-APAT mononuclear-macrophages was detected by real-time fluorescence quantitative PCR method. Relative expression of the gene was calculated by the Δ Δ Ct method using GAPDH as an internal control.

The amplification ICAM1 primer sequence is as follows:

Forward 5'-TCTGTGTCCCCCCTCAAAAGTC-3'，SEQ ID NO.12；

Reverse 5'-GGGTCTCTATGCCCAACAA-3'，SEQ ID NO.13。

the sequence of the TFN alpha primer for amplification is as follows:

Forward 5'-CCGAGTGACAAGCCTGTA-3'，SEQ ID NO.14；

Reverse 5'-GGACCTGGGAGTAGATGAG-3'，SEQ ID NO.15。

the amplification MCP1 primer sequence is as follows:

Forward 5'-CAAACTGAAGCTCGCACTCTCGCC-3'，SEQ ID NO.16；

Reverse 5'-ATTCTTGGGTTGTGGAGTGAGTGTTCA-3'，SEQ ID NO.17。

the amplification GAPDH primer sequences are as follows:

Forward 5'-GAAGGTGAAGGTCGGAGTCA-3'，SEQ ID NO.4；

Reverse 5'-GGAAGATGGTGATGGGATTTC-3'，SEQ ID NO.5。

the results show that: lncRNA APAT promoted the inflammatory response of monocytes-macrophages, mRNA expression levels of cytokines were significantly increased, ICAM1 increased 1.4-fold, TNF α increased 1.8-fold, and MCP1 increased 87% (fig. 4A).

Use of lncRNA APAT inhibitors in monocyte-macrophage inflammatory response

The inventors designed a panel of inhibitors of lncRNA APAT, including antisense oligonucleotides and small interfering RNAs, that target lncRNA APAT molecules that degrade cytoplasm and nucleus, respectively; the antisense oligonucleotide sequence is shown in SEQ ID NO.6-8, and the small interfering RNA nucleotide sequence is shown in SEQ ID NO. 9-11.

The antisense oligonucleotide and the small interfering RNA have the following nucleotide sequences:

antisense oligonucleotides:

5’-CAGAAGAACTGTCCAGAAAA-3’，SEQ ID NO.6，

5’-CCAGAAAACTCACAGAATCA-3’，SEQ ID NO.7，

5’-TAAGAAATAATGCAGCGCAG-3’，SEQ ID NO.8；

small interfering RNA:

5’-CCAGCTTGCATCAGAAGAA-3’，SEQ ID NO.9，

5’-TGGACTCACCACCTATCAA-3’，SEQ ID NO.10，

5’-GCAGCATACATCCAGAGAT-3’，SEQ ID NO.11。

an inhibitor of lncRNA APAT comprising the nucleotide sequence shown in SEQ ID NO 6-11 was transfected into monocyte-macrophages using conventional transfection methods. After 48 hours of culture, the mRNA expression level of the inflammatory factor was detected by real-time fluorescent quantitative PCR method as described above.

The results show that: lncRNA APAT inhibitors inhibited the inflammatory response of monocytes-macrophages, and the mRNA expression levels of the cytokines were significantly reduced, 48% for ICAM1, 38% for TNF α, and 22% for MCP1 (fig. 4B).

Example 5 Effect of lncRNA APAT and inhibitors thereof on monocyte-macrophage adhesion function

The inventors explored the effect of lncRNA APAT and its inhibitors on monocyte-macrophage adhesion ability through cell adhesion experiments.

The cell adhesion experiment operating method comprises the following steps: human umbilical vein endothelial cells were seeded in 12-well culture plates and adhesion experiments were performed when the degree of cell fusion reached 90%. Taking mononuclear-macrophage in exponential growth phase, and using RPMI-1640 culture medium to resuspend mononuclear-macrophage to 1 × 10⁶Per mL, 5. mu.L of CellTracker TM CM-Dil red fluorescent dye (Cat. # C7000, Invitrogen, Carlsbad, CA, USA) was added to 1mL of monocyte-macrophage and incubated at 37 ℃ for 30 minutes. The labeled monocyte-macrophages were washed twice with PBS, then resuspended in RPMI-1640 medium, 200. mu.L of the monocyte-macrophage suspension was added to each well, and after incubation at 37 ℃ for 30 minutes, washed twice with PBS. Photographs were taken under the fluorescence microscope DMI-4000B (Leica, Wetzlar, Germany), 5 fields were selected, and the number of adhered mononuclear-macrophages per field was calculated.

The results show that: lncRNA APAT promoted monocyte-macrophage adhesion to endothelial cells 2-fold (fig. 5A). lncRNA APAT inhibitors significantly inhibited monocyte-macrophage adhesion to endothelial cells by 53% (fig. 5B).

Example 6 Effect of lncRNA APAT and inhibitors thereof on the lipid accumulating Capacity of Mono-macrophages

Effect of lncRNA APAT and inhibitors thereof on the lipid phagocytic Capacity of monocyte-macrophages

The inventor adopts an oil red O experiment to detect the function of lncRNA APAT and an inhibitor thereof in the lipid phagocytosis capacity of mononuclear-macrophages, and detects the mRNA expression level of lipid phagocyte scavenger receptor A1(scavenger receptor A1, SR-A1) and CD36 molecules in the mononuclear-macrophages by a real-time fluorescence quantitative PCR method.

The oil red O experiment operation method comprises the following steps: mixing 2.5X 10⁵Mononuclear-macrophages in exponential growth phase were inoculated into 12-well plates containing cell slide, treated with PMA for 24 hours, replaced with fresh medium, incubated for 24 hours, the medium was changed to a culture of 1% fetal bovine serum, stimulated with oxidized low density lipoprotein (50 μ g/ml) (Cat. # YB-002, YIyuan Biotech, Guangzhou, China) for 12 hours, slide was taken, stained with 0.3% oil red O reagent (Sigma-Aldrich, Saint Louis, MO, USA) for 2 minutes at room temperature, stained with hematoxylin (ZSGO-BIO, Beijing, China) for 10 seconds, glycerol slides were visualized using a Leica DM6000B optical microscope (Leica Microsystem, Germany). Lipid droplets are red and cell nuclei are bluish-purple.

The mRNA expression levels of lipid phagocytosis genes SR-A1 and CD36 are detected by a real-time fluorescent quantitative PCR method.

The sequence of the SR-A1 amplification primer is as follows:

an upstream primer: 5'-GATGCTCGCTCAATGACA-3', SEQ ID NO. 18;

a downstream primer: 5'-GCTGCCACTATTCCAATGA-3', SEQ ID NO. 19;

the amplification CD36 primer sequence is as follows:

an upstream primer: 5'-TGATGAACAGCAGCAACA-3', SEQ ID NO. 20;

a downstream primer: 5'-CACAGCCAGATTGAGAACT-3', SEQ ID NO. 21.

The results show that: lncRNA APAT significantly promoted mRNA expression levels of lipid phagocytic genes of monocytes-macrophages, with a 4.2-fold increase in SR-a1 and a 1.5-fold increase in CD36 (fig. 6A). Further, the oil red O experiment showed that lncRNA APAT significantly promoted lipid phagocytosis of monocyte-macrophages, and lncRNA APAT inhibitor significantly inhibited lipid phagocytosis of monocyte-macrophages (fig. 6B).

Effect of lncRNA APAT and inhibitors thereof on the cholesterol efflux capacity of monocyte-macrophages

The inventor adopts a cholesterol efflux experiment to detect the effect of lncRNA APAT and an inhibitor thereof on cholesterol efflux of mononuclear-macrophages, and detects the mRNA expression levels of cholesterol efflux related gene scavenger receptor B1(scavenger receptor A1, SR-B1) and ATP binding cassette subfamily G member 1(ATP binding cassette subset G member 1, ABCG1) in the mononuclear-macrophages by a real-time fluorescence quantitative PCR method.

The operating method of the cholesterol efflux experiment comprises the following steps: seeding of 96 well cell culture plates 2X 10⁴THP-1 monocytes in exponential growth phase were induced with PMA (100ng/ml) for 24 hours and transformed into monocyte-macrophages. 48 hours after transfection of APAT, 50. mu.g/mL acetylated low density lipoprotein (Cat. # YB-004, Yiyuan Biotech, Guangzhou, China) and 5. mu.g/mL NBD cholesterol (Cat. # N1148, Invitrogen, Carlsbad, CA, USA) were added per well and incubated at 37 ℃ for 12 hours; the cells were washed 3 times with serum-free RPMI-1640 medium and then incubated for 4 hours with changing to RPMI-1640 medium containing 20. mu.g/mL ApoA1 and 0.2% BSA, inducing cholesterol efflux. Fluorescence intensity was measured using an Infinite M200Pro Grating-type multifunctional microplate reader (Tecan, Zurich, Switzerland), and the cholesterol efflux rate of cells was calculated.

Cholesterol efflux ratio is culture supernatant fluorescence intensity/(culture medium + cell fluorescence intensity).

The real-time fluorescent quantitative PCR method detects the mRNA expression level of cholesterol efflux related genes SR-B1 and ABCG1 in the mononuclear-macrophage.

The sequence of the SR-B1 amplification primer is as follows:

an upstream primer: 5'-GCAACATCACCTTCAACAA-3', SEQ ID NO. 22;

a downstream primer: 5'-GGCTTATTCTCCATCATCAC-3', SEQ ID NO. 23;

the sequence of the amplification ABCG1 primer is as follows:

an upstream primer: 5'-CGGCTTCCTCTTCTTCTC-3', SEQ ID NO. 24;

a downstream primer: 5'-CCAGTAGTTCAGGTGTTCC-3', SEQ ID NO. 25.

The results show that: the lncRNA APAT remarkably inhibits the mRNA expression level of ABCG1 and SR-B1 genes, the ABCG1 expression is reduced by 36%, and the SR-B1 expression is reduced by 38% (FIG. 7A). In contrast, lncRNA APAT inhibitor significantly promoted the mRNA expression levels of ABCG1 and SR-B1 genes, with 88% increase in ABCG1 expression and 61% increase in SR-B1 expression (FIG. 7B). Cholesterol efflux experiments showed that lncRNA APAT inhibitors significantly promoted cholesterol efflux capacity of monocytes-macrophages by 43% (fig. 7C).

Example 7 IncRNA APAT promotes progression of atherosclerotic aortic plaques

To further elucidate the effect of lncRNA APAT on atherosclerotic plaque progression in vivo, the inventors established a mouse model of atherosclerosis and analyzed the effect of lncRNA APAT on the number and area of atherosclerotic plaque formation in mouse aorta and inflammatory response in mouse macrophages.

Preparing an mPCSK9 atherosclerosis mouse model of mononuclear cell specifically expressing lncRNA APAT, wherein the mouse model is a homozygous mouse (APAT) of mononuclear-macrophage specifically expressing lncRNA APAT and inducing atherosclerosis by administering mPCSK9^floxed/^floxed，Lyz2-Cre)。

(1) First, a homozygote mouse model was constructed in which monocytes specifically express lncRNA APAT: inserting CAG-loxP-Stop-loxP-APAT-polyA sequence into the first intron of ROSA26 gene of chromosome 6 of C57BL/6N mouse by using CRISPR-Cas9 technology to obtain control group mouse (APAT)^floxed/^floxed). Expression of APAT in mice is regulated by Cre recombinase. Lyz2-Cre mouse is a kind of genetically engineered mouse with monocyte specific expression of Cre recombinase. The control group mice were mated with Lyz2-Cre mice to obtain homozygote mice (APAT) in which monocytes specifically express lncRNA APAT^floxed/^floxed，Lyz2-Cre)。

(2) Further, the structureBuilding an atherosclerosis mouse model: the experimental group homozygote mice (APAT)^floxed/^floxedLyz2-Cre), feeding to 8 weeks old, and tail vein injecting 5X 10¹¹vg AAV-D377Y-mPCSK9 adeno-associated virus (Cat. # AV208001-AV8, Vigene Biosciences, Shandong, China), high fat diet (Daye, Beijing, China) was fed for 12 weeks to induce the formation of a homozygote mouse model of monocyte-specific lncRNA APAT with atherosclerotic characteristics (APAT)^floxed/^floxed，Lyz2-Cre)。

Control mice (APAT)^floxed/^floxed) The method of inducing an atherosclerosis model of (3), as described above.

The control group mice and the experimental group mice each contained 10 mice.

The atherosclerosis condition of the aorta of the mice is detected by adopting an oil red O experiment: after anesthetizing the mice, the aorta was separated and placed in a 6cm petri dish (Cat. #430166, Corning Incorporated, Corning, NY, USA) and stained with oil red O stain for 30 minutes. After staining, the aorta was transferred to a new 6cm petri dish, and a phosphate buffer was added to differentiate, and the blood vessel portion with plaque was bright red, and the blood vessel portion without plaque was transparent.

The results show that: lncRNA APAT significantly increased atherosclerotic plaque number (fig. 8A) and plaque area (fig. 8B) in the aortic region, as compared to control mice, primarily manifested as promoting lesions in the thoracic aorta of mice (fig. 8C).

Furthermore, the inventor performs pathological tissue staining on atherosclerotic plaque parts of thoracic aorta of mice of a control group and mice of an experimental group, and detects the characteristics of atherosclerotic plaque.

(1) Preparing pathological sections of atherosclerotic plaque parts: after anesthetizing the mice, the thoracic aortic plaque Tissue is separated, and embedded into Tissue after quick freezing by liquid nitrogen

Compound reagent (Cat #4583, Sakura Finetek, Torrance, CA, USA), 8 μm frozen tissue sections were cut out laterally using a CM1950 cryostat (Leica Biosystems, Nussloch, Germany) instrumentAnd stored in a refrigerator at-80 ℃ for further case staining.

(2) Hematoxylin-eosin staining method: hematoxylin-eosin staining was performed on the above pathological sections. Staining cell nucleus with hematoxylin solution for 3 min; washing with running water, and differentiating for several seconds by using 1% hydrochloric acid ethanol; returning the tap water to blue; dyeing with eosin dye liquor for 1 min; washing with running water, and dehydrating with 95% ethanol for three times; dehydrating with anhydrous alcohol, transparent xylene, and sealing with neutral gum; photographs were taken using a Leica DM6000B fully automated upright fluorescence microscope (Leica Microsystem, Germany).

Hematoxylin-eosin pathological staining shows that the thoracic aorta wall of the control group mouse is smoother, the plaque area is smaller, lipid and necrosis disintegrating substances and cholesterol are less crystallized and calcified, while the thoracic aorta wall of the experimental group mouse with monocyte specific expression lncRNA APAT is rougher, the plaque area is larger, and more lipid and necrosis disintegrating substances and more cholesterol are crystallized and calcified in the plaque (fig. 9A); lncRNA APAT significantly promoted aortic plaque formation in atherosclerotic model mice by 46% (fig. 9B).

Further, the inventors examined mRNA expression levels of peripheral blood mononuclear cell inflammatory factors, lipid phagocytosis, and cholesterol efflux genes in a mouse model of atherosclerosis.

Peripheral blood mononuclear cells of mice were isolated and cultured in the same manner as the isolation method of human peripheral blood mononuclear cells in example 2. After separation, the cells are inoculated on a 12-hole cell plate, cultured in a cell culture box for 2 hours, and after the cells adhere to the wall, the supernatant is discarded, and the cells are collected in Trizol. The mRNA expression levels of inflammatory factors, lipid phagocytosis and cholesterol efflux genes in cells are detected by a real-time fluorescent quantitative PCR method.

The results show that: lncRNA APAT significantly promoted the expression levels of inflammatory factors (IL6, TNF α, fig. 10A) and lipid phagocytic genes (LOX1, fig. 10B) in peripheral blood mononuclear cells of the atherosclerosis model mice compared to the control group.

In conclusion, lncRNA APAT has the function of promoting the quantity and the area of the aortic atherosclerotic plaques of the atherosclerosis model mice; promoting inflammatory reaction in peripheral blood mononuclear cells of an atherosclerosis model mouse.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Sequence listing

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Claims (10)

1. The application of a reagent for detecting the expression level of lncRNA APAT in the preparation of products for diagnosing atherosclerotic heart disease is disclosed, wherein the lncRNA APAT nucleotide sequence is shown as SEQ ID NO. 1.

2. The use of claim 1, wherein the lncRNA APAT is highly expressed in the peripheral blood of coronary heart disease patients with mixed vulnerable plaques of coronary atherosclerosis.

3. The use of claim 2, wherein the lncRNA APAT promotes monocyte-macrophage inflammation and lipid phagocytosis; inhibiting the cholesterol efflux capacity of monocyte-macrophages; promoting the number and area of atherosclerotic plaque formation.

4. A kit for early diagnosis of atherosclerotic heart disease or prediction of atherosclerotic plaque stability and progression, comprising means for detecting the expression level of lncRNA APAT and instructions for use of the kit; the lncRNA APAT nucleotide sequence is shown in SEQ ID NO. 1.

5. The kit of claim 4, wherein the means comprise a primer pair for specifically detecting the expression level of lncRNA APAT, and the sequences of the primer pair are shown as SEQ ID No.2 and SEQ ID No. 3.

6. An lncRNA APAT inhibitor is characterized in that the lncRNA APAT nucleotide sequence is shown as SEQ ID NO. 1; the inhibitor comprises an agent that inhibits lncRNA APAT expression.

7. The inhibitor of claim 6, wherein the agent that inhibits the expression of lncRNA APAT comprises an antisense oligonucleotide and/or a small interfering RNA.

8. Use of the inhibitor of claim 6 or 7 for the preparation of a pharmaceutical composition for the prevention or treatment of atherosclerotic heart disease.

9. The use of claim 8, wherein the inhibitor has the effect of inhibiting monocyte-macrophage inflammation and lipid phagocytosis; promoting cholesterol efflux capacity of monocyte-macrophages; preferably, the genes related to inflammatory factors of monocyte-macrophages include MCP1, TNF α, VCAM1, IL1 β and IL 6.

10. An mPCSK9 atherosclerosis mouse model of monocyte specificity expression lncRNA APAT is applied to the preparation of a research model of atherosclerotic heart disease pathogenesis or a screening model of drugs for treating atherosclerotic heart disease; the mouse model is a homozygote mouse (APAT) which specifically expresses lncRNA APAT by mononuclear-macrophage and induces atherosclerosis by administration of mPCSK9^floxed/^floxed，Lyz2-Cre)。

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