Diagnostic and prognostic value of miR-885-5p in acute coronary syndrome and its regulatory mechanisms in endothelial injury

Abstract

Background

Acute coronary syndrome (ACS) is a common emergency in the cardiovascular system. The prevention, diagnosis, and treatment of ACS are critical and continuous issues in the clinic. Identifying non-invasive and promising biomarkers for ACS is of great clinical significance. This study evaluated the significance of miR-885-5p in the early screening, severity evaluation, and prognosis prediction of ACS, aiming to explore novel biomarkers for its clinical management.

Methods

Serum miR-885-5p levels were compared between 134 ACS patients and 122 non-ACS patients. The clinical significance of miR-885-5p was assessed from the perspectives of discriminating ACS patients, risk prediction, severity evaluation, and prognosis prediction. In vitro, the ox-LDL-induced HCAEC models were employed, and the regulatory effects of miR-885-5p on cell viability, inflammation, oxidative stress, and endothelial function were estimated. The regulatory mechanism was explored, focusing on the involvement of FBXO28.

Results

Increasing serum miR-885-5p could discriminate ACS patients and predict onset risk. miR-885-5p was positively correlated with myocardial injury-, severity-, and endothelial dysfunction-related clinicopathological features and could predict the risk of MACEs in ACS patients. In HCAECs, ox-LDL induced significant upregulation of miR-885-5p, suppressed cell viability, enhanced inflammation, promoted oxidative stress, and induced endothelial injury. Silencing miR-885-5p could protect HCAECs from ox-LDL-induced injury. FBXO28 was predicted as a direct target of miR-885-5p, negatively regulated by miR-885-5p. The knockdown of FBXO28 could reverse the protective effect of miR-885-5p silencing.

Conclusions

Circulating miR-885-5p served as a biomarker for the diagnosis and prognosis of ACS. Silencing miR-885-5p could alleviate ox-LDL-induced endothelial cell injury by targeting FBXO28.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-026-05870-1.

Background

Coronary artery disease (CAD) is a global health problem, and its incidence rate is gradually increasing due to the acceleration of life, sudden increase in work pressure, and irregular diet. Acute coronary syndrome (ACS) is the most common and critical type of CAD, with the characteristics of sudden onset and rapid progression. Currently, the onset age of ACS tends to be younger, which cannot be totally interpreted by the existing risk factors. Hence, there might be easily overlooked risk factors that mediate the occurrence and development of ACS, which would be promising biomarkers. The rupture or erosion of the atherosclerotic plaques in the coronary arteries would lead to thrombosis, which has been widely accepted as the major etiology of ACS, and atherosclerosis has also been considered a critical risk factor for ACS [1]. The etiological processes of atherosclerosis, such as inflammation, oxidative stress, abnormal lipoprotein metabolism, endothelial injury and dysfunction, are also associated with the development of ACS [2, 3]. Due to the sudden attack, the early and timely screening of ACS is of great clinical significance, which would improve patients’ prognosis. The current diagnostic and evaluation methods are mostly dependent on the subjectivity of diagnostic physicians [4]. More importantly, the present diagnostic methods are mainly based on invasive examinations, which dramatically limit patients’ compliance [5]. There are also a number of patients limited to the allergic reaction to the contrast agents. Therefore, exploration of non-invasive biomarkers with easily-obtained samples is of clinical importance to improve the prognosis of ACS patients.

Recent studies have noticed the clinical potential of microRNAs (miRNAs) in human diseases, which are associated with disease development and could serve as diagnostic biomarkers. In ACS, miRNAs have been considered to have great potential in indicating disease severity and mediating disease development [6]. Several miRNAs have been revealed to be dysregulated in ACS and show close association with coronary stenosis, implying their potential in ACS diagnosis and prediction [7–10]. The regulatory effects of miRNAs on endothelial cellular function, atherosclerotic plaque stability, and smooth vascular muscle cell function could interpret the underlying molecular mechanism. miR-885-5p was demonstrated to show a close association with the lipoprotein metabolism and was associated with the progression of fatty liver [11]. Moreover, miR-885-5p has been revealed to be correlated with cardiac remodeling in ACS patients with favorable outcomes [12]. miR-885-5p was also identified to be involved in myocardial injury, regulating myocardial cell viability and apoptosis [13–15]. Therefore, miR-885-5p was considered to play critical roles in the development of ACS and was hypothesized as a promising biomarker indicating ACS onset and predicting patients’ disease severity and prognosis. However, there was a lack of direct evidence confirming the specific function in ACS.

This study evaluated the potential of miR-885-5p in ACS onset and development with clinical trials. Its functional mechanisms were evaluated in coronary artery endothelial cells to disclose the regulation of endothelial function by miR-885-5p. In mechanism, FBXO28 was predicted as a downstream target of miR-885-5p, which has also been identified as critically involved in heart diseases and was demonstrated to modulate lipid metabolism, inflammation, and various ACS-related pathological processes [16, 17]. Previous study demonstrated FBXO28 mediated the promoting effect of miR-184 on cardiomyocytes from H₂O₂-induced inflammation, oxidative stress, and cell apoptosis [18]. Considering the similar inducement in endothelial dysfunction, the involvement of FBXO28 in the function of miR-885-5p in endothelial cells was evaluated.

Methods

Study subjects and sampling

A total of 256 patients suspected of ACS and receiving coronary angiography (CAG) examination were included in this study. Based on the results of CAG, the enrolled patients were divided into ACS (n = 134) and non-ACS (n = 122) groups combing with clinical symptoms, electrocardiographic (ECG) changes, and myocardial markers: (1) the main blood vessels (diameter ≥ 2.0 mm) were narrow; (2) the degree of stenosis was ≥ 50%; (3) troponin elevated (for NSTEMI patients); (4) absence of troponin elevation but with typical symptoms of angina pectoris; (5) characteristic ECG abnormalities (ST-segment deviation or T-wave inversion) for all ACS subtypes. Patients with one of the following terms were excluded: (1) systemic inflammation; (2) kidney and liver dysfunction; (3) history of cardiovascular diseases (including prior myocardial infarction, coronary revascularization, heart failure, or valvular heart disease); (4) combining with malignant tumors, autoimmune diseases, and blood system diseases; (5) patients receiving long-term use of immunosuppressants or glucocorticoids. The control group involved patients diagnosed with stable angina (n = 58), arrhythmia (n = 53), and healthy individuals (n = 11). The sample size has been validated by the Power analysis at α = 0.05, effect size = 0.5, and the power of the sample size reached 0.9, indicating the high statistical adequacy.

Venous blood samples were collected from all participants into pro-coagulation tubes and stood at room temperature. Collected blood samples were centrifuged at 3000 rpm/min for 15 min, and the supernatant was collected as the serum. Isolated serum was stored at -80 °C for the following analyses.

Follow-up survey

The enrolled ACS patients were followed up for 1 year through outpatient review or by telephone. The occurrence of major adverse cardiovascular events (MACEs) was recorded as the endpoint of the follow-up survey.

Cell culture and inducement

Human coronary artery endothelial cells (HCAECs) were maintained with endothelial cell culture medium (ECM) supplemented with 5% FBS, 1% endothelial cell growth supplement, and 1% penicillin/streptomycin. Cell culture was conducted at 37 °C with 5% CO₂ until the fusion reached 70–90%.

Cells were treated with 50 µg/mL ox-LDL after cell fusion reached 80%. Stimulated cells were available for further experiments after 48 h of incubation at 37 °C. Cell transfection was also conducted after cell fusion reached 80%. Cells were transfected with miR-885-5p inhibitor for its knockdown or miR-885-5p mimic for its overexpression using Lipofectamine 3000 (Invitrogen, USA). For the co-regulation of miR-885-5p and FBXO28, small-interference RNA of FBXO28 (si-FBXO28) was transfected with miR-885-5p inhibitor. Cell transfection was carried out at room temperature, and transfected cells were available after 48 h incubation at 37 °C.

Real-time quantitative PCR

Serum samples and cells were lysed with Trizol reagent (Beyotime, China) at room temperature for 10 min, followed by adding chloroform. After maintaining it for 3 min, the mixture was centrifuged at 12,000 rpm/min for 15 min, and the topmost layer was collected. The aqueous phase was further mixed with an equal volume of isopropyl alcohol and stood at room temperature for 10 min. Further centrifugation at 12,000 rpm/min was conducted for 10 min to obtain the isolated RNA. The precipitate was collected and washed with 75% ethanol twice. The concentration and purity of isolated RNA were evaluated by the values of OD260/280 and OD260/230 using NanoDrop One. OD260/280 values between 1.8 and 2.0 and OD260/230 values between 2.0 and 2.2 were considered acceptable for subsequent experiments. RNA integrity was also verified by 1.5% agarose gel electrophoresis to ensure no obvious degradation.

Reverse transcription was conducted with the TaqMan MicroRNA Reverse Transcription Kit (Life Technologies, USA). PCR amplification was further conducted with the generated cDNA on the 7500 PCR system with the help of the SYBR Green kit. The amplification efficiency reached 90–110%, and the melt curve analysis was performed after qPCR amplification, and a single, sharp melting peak was observed for each target miRNA, confirming no non-specific amplification or primer dimers; agarose gel electrophoresis of qPCR products was further conducted to verify the target fragment size. The relative expression levels were calculated by the 2^{− deltdeltct} method with cel-miR-39 and GAPDH as internal references according to previous studies and preliminary experiments [19, 20]. cel-miR-39 had no endogenous expression in serum and cells of the study subjects, and its Ct values were stable (CV < 5%) across all samples, indicating it could effectively normalize for pre-analytical variables. GAPDH was used as an endogenous reference to complement the normalization effect, ensuring the accuracy of relative expression calculation.

Enzyme-Linked Immunosorbent Assay (ELSA)

Cell incubation was centrifuged, and the supernatant was collected for the evaluation of inflammatory cytokines. The protein concentrations of IL-6, IL-10, and IFN-γ were analyzed with corresponding kits according to the manufacturer’s protocols and calculated based on the standard curve.

Cell viability assay

Cells were seeded into 96-well plates and supplied with a complete culture medium. Cells were maintained at 37 °C for 24, 48, 72, and 96 h, followed by adding cell counting-8 (CCK8) kits. Absorbance at 450 nm was detected with a microplate reader after 2 h of CCK8 kit addition. Cell viability was represented by the changes in OD450 with incubation time.

Oxidative stress assay

The oxidative stress in HCAECs was evaluated by MDA concentration, SOD activity, and concentration of eNOS. The concentration of MDA and eNOS was evaluated by ELISA with corresponding kits, including Human MDA ELISA kit and Human eNOS ELISA kit (R&D Systems, USA). While the activity of SOD was evaluated utilizing the SOD determination kit (Sigma-Aldrich, USA) according to the manufacturer’s protocol.

Endothelial barrier function assay

Cells were seeded into the upper chambers of 12-well Transwell plates, and the lower chambers were filled with ECM culture medium. The plates were incubated at 37 °C with 5% CO₂ for 7 days until a monolayer of cells was formed. The trans-endothelial electrical resistance (TEER) was measured with the EVOM resistance meter (World Precision Instrument, USA).

Cells in the upper chambers were supplied with 1 mg/mL FITC-Detran (Sigma-Aldrich, USA). After incubation at 37 °C for 1 h, the fluorescence intensity of FITC-Dextran in the lower chambers was detected by a multimode microplate reader with excitation at 485 nm and emission at 530 nm. The permeability coefficient = (RFU_lower/RFU_upper)×V×(1/time) ×(1/area).

Statistical analysis

The receiver operating characteristic (ROC) curve was employed to evaluate the significance of miR-885-5p in discriminating ACS patients. Logistic regression analysis was performed to identify risk factors for the ACS development and MACEs. Chi-square test and Pearson correlation analysis were employed to evaluate the association of miR-885-5p and patients’ pathological features. Difference comparison was conducted with Student’s t-test, one-way ANOVA, and two-way ANOVA. Measurement data were presented as mean ± SD, and counting data were recorded as number and corresponding percentage. P < 0.05 indicates statistical significance.

Results

Basic conditions of study subjects

Patients with ACS and without ACS are matched in age and gender composition with no significant difference. The liver function and renal function of patients in both groups are normal with no significant differences. ACS patients showed abnormal blood pressure and blood lipid levels. The SBP (75.06 ± 7.68 vs. 73.22 ± 8.22), TG (1.53 ± 0.54 vs. 1.33 ± 0.57), and LDL (3.09 ± 0.61 vs. 2.89 ± 0.45) levels of ACS patients were significantly higher than those of patients in non-ACS patients (Table 1).

Table 1.

Baseline information of study subjects

	Non-ACS (n = 122)	ACS (n = 134)	P-value
Age	57.87 ± 8.16	57.77 ± 8.88	0.463
Gender	75/47	82/52	0.963
Blood pressure
SBP	118.08 ± 8.12	119.52 ± 11.11	0.117
DBP	73.22 ± 8.22	75.06 ± 7.68	0.033
Blood lipid
TC	4.64 ± 0.67	4.60 ± 0.74	0.302
TG	1.33 ± 0.57	1.53 ± 0.54	0.003
HDL	1.28 ± 0.35	1.25 ± 0.34	0.256
LDL	2.89 ± 0.45	3.09 ± 0.61	0.001
Liver function
TP	65.30 ± 4.77	64.75 ± 5.00	0.184
ALB	40.80 ± 5.79	41.48 ± 4.89	0.154
TBIL	11.92 ± 1.05	11.87 ± 1.13	0.345
Renal function
Scr	56.32 ± 7.80	58.79 ± 41.77	0.251
UA	286.57 ± 57.70	282.96 ± 45.17	0.283

SBP systolic blood pressure, mmHg, DBP diastolic blood pressure, mmHg, TC total cholesterol, mmol/L, TG triglyceride, mmol/L, HDL high-density lipoprotein, mmol/L, LDL low-density lipoprotein, mmol/L, TP total protein, g/L, ALB albumin, g/L, TBIL total bilirubin, µmol/L, Scr serum creatinine, µmol/L, UA uric acid, µmol/L

Significance of miR-885-5p in screening and prognosis of ACS patients

Comparing the serum miR-885-5p levels between the non-ACS and ACS groups, the significant upregulation of miR-885-5p was observed in ACS patients (Fig. 1a). Increasing serum miR-885-5p levels could discriminate ACS patients with a sensitivity and specificity of 77.61% and 80.33%, respectively (AUC = 0.857, Fig. 1b). Cross validation further confirmed the robust diagnostic performance. The training set (70%) achieving an AUC of 0.840 (95% CI: 0.784–0.896), sensitivity of 75.79%, and specificity of 80.00%, and the validation set (30%) yielding an AUC of 0.895 (95% CI: 0.824–0.967), sensitivity of 84.62%, and specificity of 81.25% (Table S1). Univariate logistic analysis identified miR-885-5p (OR = 14.156, 95% CI = 7.741–25.884), blood pressure (SBP and DBP), and blood lipid (TG and LDL) parameters as critical risk factors for the incidence of ACS (Fig. 1c). Further multivariate analysis confirmed the predictive value of miR-885-5p (OR = 19.805, 95% CI = 9.698–40.447) and blood pressure-related indicators, SBP (OR = 2.426, 95% CI = 1.268–4.642) and DBP (OR = 3.344, 95% CI = 1.663–6.725, Fig. 1d). Collinearity has been excluded from the factors included in multivariate logistic regression (all tolerance > 0.9, VIF < 10, Table S2).

Fig. 1.

Diagnostic and risk prediction potential of miR-885-5p in ACS. a, b Serum expression of miR-885-5p in non-ACS and ACS patients (a) and ROC curve based on serum miR-885-5p discriminating these two groups of patients (b). ^****P < 0.0001. c-d. Univariate (c) and multivariate (d) logistic regression analyses evaluating risk factors for ACS

Serum miR-885-5p levels were positively correlated with CK-MB levels (r = 0.655), cTnI levels (r = 0.716), GRACE score (r = 0.637), SYNTAX score (r = 0.759), SICAM-1 levels (r = 0.589), and vWF levels (r = 0.649, all P < 0.0001, Table 2).

Table 2.

Correlation of serum miR-885-5p with disease conditions of ACS patients

	Correlation coefficients	P-value
CK-MB	0.655	< 0.0001
cTnI	0.716	< 0.0001
GRACE score	0.637	< 0.0001
SYNTAX score	0.759	< 0.0001
SICAM-1	0.589	< 0.0001
vWF	0.649	< 0.0001

CK-MB creatine kinase-MB, ng/mL, cTnI cardiac troponin I, ng/L, GRACE Global Registry of Acute Coronary Events score, SYNTAX SYNergy between PCI with TAXus and Cardiac Surgery score, SICAM-1 soluble Intercellular Adhesion Molecule-1, ng/mL, vWF von Willebrand Factor, ng/mL

Based on the occurrence of MACEs, ACS patients were divided into MACE and non-MACE groups. Patients developing MACEs showed higher serum miR-885-5p levels relative to the non-MACE group (Fig. 2a). Moreover, miR-885-5p (OR = 8.370, 95% CI = 2.977–23.532), HDL (OR = 2.619, 95% CI = 1.144–5.999), and LDL (OR = 2.727, 95% CI = 1.190–6.250) showed significance in predicting the incidence of MACE in ACS patients (Fig. 2b). Further multivariate logistic regression analysis also revealed the significant predictive values of these three indicators (all P < 0.05, Fig. 2c). Collinearity has been excluded from the factors included in multivariate logistic regression (all tolerance > 0.9, VIF < 10, Table S3).

Fig. 2.

Prognostic value of miR-885-5p in ACS. a Comparison of serum miR-885-5p in ACS patients with or without MACEs. ^****P < 0.0001. b-c. Univariate (b) and multivariate (c) logistic regression analyses evaluating risk factors for the occurrence of MACEs

Regulatory effect of miR-885-5p on HCAECs biological function

Ox-LDL-induced HCAECs mimic the conditions during the onset of ACS. Mir-885-5p was found to significantly upregulate under the treatment of ox-LDL, which was suppressed by the transfection of its inhibitor (Fig. 3a). Meanwhile, the treatment of ox-LDL also inhibited cell viability (Fig. 3b), promoted the expression of inflammatory cytokines (IL-6 and IFN-γ), and suppressed anti-inflammation cytokines (IL-10, Fig. 3c). The increasing contents of MDA, decreasing activity of SOD, and decreasing contents of eNOS indicated the induction of oxidative stress by ox-LDL (Fig. 3d). Silencing miR-885-5p alleviated ox-LDL-induced cell injury, which improved cell viability (Fig. 3b) and suppressed inflammation (Fig. 3c) and oxidative stress (Fig. 3d).

Fig. 3.

Regulatory effects of miR-885-5p on biological functions of HCAECs. a expression and regulation of miR-885-5p under the treatment of ox-LDL and cell transfection. b, c Regulation of cell viability (b), inflammation (c), and oxidative stress (d) by miR-885-5p in ox-LDL-induced HCAECs. e-g. Regulation of endothelial function evaluated by TEER (e), cell permeability (f), and related molecules (g). ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001

Furthermore, considering the observed association between serum miR-885-5p and endothelial function indicators in ACS patients, its regulatory effects on endothelial injury of HCAECs were evaluated. Ox-LDL decreased TEER (Fig. 3e) and increased fluorescence permeability (Fig. 3f) of HCAECs, and endothelial function-related molecules were also inhibited by the treatment of ox-LDL (Fig. 3g). Silencing miR-885-5p significantly alleviated the inhibitory effect of ox-LDL on HCAECs, as the recovered TEER, reducing permeability, and improved expression of VE-cadherin, claudin-5, and occludin (Fig. 3e-g).

Involvement of FBXO28 in the regulatory effect of miR-885-5p

The downstream targets of miR-885-5p were predicted from three public databases, including Target Scan, miRDB, and Starbase, and a total of 63 targets were enriched in the intersection (Fig. 4a). The inducement of ox-LDL reduced the expression of FBXO28, and under the treatment of ox-LDL, silencing miR-885-5p significantly increased the expression of FBXO28, while the transfection of its siRNA could attenuate this promotion (Fig. 4b). Several binding sites were predicted in the 3’UTR of FBXO28 with miR-885-5p, and luciferase reporter assay revealed the negative regulation of FBXO28 luciferase activity by miR-885-5p in ox-LDL-induced HCAECs (Fig. 4c).

Fig. 4.

Targeting relationship between miR-885-5p and FBXO28. a Prediction of downstream targets of miR-885-5p from Target Scan, miRDB, and Starbase databases. b, c. Regulation of FBXO28 expression (b) and luciferase activity (c) by miR-885-5p in ox-LDL-treated HCAECs. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001

The knockdown of FBXO28 significantly reversed the protective effect of miR-885-5p on ox-LDL-induced cell injury on HCAECs, which suppressed cell viability (Fig. 5a), enhanced inflammation (Fig. 5b), and promoted oxidative stress (Fig. 5c). Additionally, silencing FBXO28 also reduced TEER (Fig. 5d) and improved fluorescence permeability (Fig. 5e). The expression of VE-cadherin, claudin-5, and occludin was also significantly suppressed by the knockdown of FBXO28 (Fig. 5f).

Fig. 5.

Involvement of FBXO28 in the function of miR-885-5p. a-c. Involvement of FBXO28 in the regulation of cell viability (a), inflammation (b), and oxidative stress (c) by miR-885-5p. d-f. Involvement of FBXO28 in the regulatory effect of miR-885-5p on endothelial function evaluated by TEER (d), cell permeability (e), and related molecules (f). ^*P < 0.05, ^**P < 0.01

Discussion

Due to the complex pathological processes, the early screening and prognosis prediction of ACS are still challenging issues in the clinic. An increasing number of new cases and mortality rates also make ACS attract special attention. Nowadays, studies have noticed the significance of circulating miRNAs in disease diagnosis and prognosis. Compared with traditional diagnostic methods, circulating miRNAs show advantages of non-invasiveness, low costs, and their sensitivity and specificity are satisfactory. Besides considering miRNAs are assisting diagnostic indicators, several miRNAs have been shown to have independent predictive value for the onset, development, and prognosis of ACS. For instance, platelet miR-587 was revealed to show a close association with the severity of ACS, considered as a potential diagnostic and prognostic biomarker [21]. miR-885-5p is a widely reported promising biomarker in human diseases, including cancer, autoimmune diseases, and neurodegenerative diseases [22–27]. Additionally, its involvement in lipid metabolism and myocardial injury implies its potential in mediating ACS progression [11, 13, 28]. Consistent with the previously reported significance of miR-885-5p in myocardial injury, increasing serum miR-885-5p was observed in ACS patients in the present study. Increasing serum miR-885-5p was revealed to discriminate ACS patients with a relatively high sensitivity and specificity, indicating its great diagnostic potential. Previous studies on miRNAs mainly focused on the deep exploration of perspective of clinical significance, such as diagnostic significance, prognostic value, or development potential. For instance, miR-140-3p was identified of great potential in discriminating ACS patients from healthy individuals, but its prognostic value has not been evaluated [29]. The present study is a multi-dimensional integration study, revealing the clinical potential of miR-885-5p in the onset, development, and outcomes of ACS. To ensure the representativeness of the study subjects, ACS patients were diagnosed based on the combination of CAG and myocardial markers (including cTnI and CK-MB). The diagnostic accuracy of these indicators would be 100% in the present study subjects, making it difficult to compare with miR-885-5p. The diagnostic efficiency of miR-885-5p should be evaluated by comparing with these present markers, to promote its clinical application with further expanding study subjects.

Insufficient blood supply to the coronary arteries is the major characteristic of ACS, and myocardial injury is the inevitable complication of ACS [30]. CK-MB and cTnI are critical indicators for myocardial injury. CK-MB mainly exists in the cytoplasm of myocardial cells and plays vital roles in cellular energy metabolism. The onset of ACS would increase the permeability of the cell membrane, and an increasing amount of CK-MB would be released into the blood circulation [31]. cTnI is the critical structural protein for myocardial cell contraction. The damaged structure of the sarcomere caused the release of binding cTnI into the blood, and due to the relatively slow biotransformation of cTnI, its increase would last a longer period than CK-MB during the development of ACS [32]. GRACE score and SYNTAX score are two major assessments for the severity and prognosis of ACS patients [33]. Herein, significantly positive correlations were observed in these indicators and scores with serum miR-885-5p levels in ACS patients, suggesting its potential in indicating disease severity. The occurrence of MACEs is a major adverse outcome in ACS patients. Risk prediction of MACEs could provide a basis for the formulation of personalized therapeutic strategies, optimizing the drug treatment, and improving patients’ prognosis [34, 35]. Among ACS patients, patients developing MACEs showed higher serum miR-885-5p levels, and together with blood lipid indicators, serum miR-885-5p was identified as a risk factor predicting MACEs in ACS patients. These findings revealed their prognostic potential in ACS. Considering individual differences, the medications cannot be uniformed for all study subjects. Although the medications are distinct, the therapeutic purpose was to improve patients’ prognosis, therefore, the difference in medications exerted weak effects on the prognostic value of miR-885-5p. However, the potential confounding influences of pharmacologic treatment should not be neglected. Future interventional studies that control medication exposure are required to disentangle these effects and validate the true nature of the reported associations. This study performed 1-year follow-up to monitor the occurrence of MACEs. One year is the core observation window of MACEs with a high occurrence due to the high risk of complications during the perioperative period, after reperfusion treatment, stent thrombosis, and malignant arrhythmia [36]. However, to comprehensively understand the prognostic significance of miR-885-5p, longer periods for follow-up survey is necessary, which could also validate its stability in risk prediction [37].

On the other hand, endothelial injury, the initial and core pathological basis of ACS, has also been observed to show a close association with serum miR-885-5p levels. SICAM-1 and vWF are two indicators of vascular endothelial injury, reflecting the activation of endothelial inflammation, endothelial injury, and participating hemostasis [38]. Both indicators would increase when the vascular endothelium is damaged. In general, the increasing levels of SICAM-1 and vWF could indicate the severe development of ACS and are associated with the high risk of MACEs in ACS patients. Hence, their positive correlations with serum miR-885-5p could also illustrate the predictive value of miR-885-5p in the development of ACS. Moreover, these findings also highlighted the involvement of endothelial dysfunction in the function of miR-885-5p. Further in vitro validation was conducted with HCAECs, the “first line of defense” for the coronary artery wall.

Dysfunction of HCAECs is the major inducing factor for ACS. The present study employed the inducement with ox-LDL to mimic the pathological conditions during the onset and development of ACS. Inflammation damages the endothelial barrier, which further aggravates the instability and even rupture of plaque, promoting disease development and resulting in the formation of thrombosis [39]. Oxidative stress would enlarge the effect and injury of inflammation and exert damage to cell structure and function [40]. Hence, both processes have been considered promoting factors for ACS development. In ox-LDL-induced HCAECs, silencing miR-885-5p could alleviate ox-LDL-induced cell injury, which enhanced cell viability and suppressed inflammation and oxidative stress. More importantly, miR-885-5p could also regulate cell permeability and the expression of molecules related to endothelial cell intercellular junction, confirming its involvement in mediating endothelial dysfunction. Hence, miR-885-5p was considered a promising therapeutic target for ACS. Except for the cell model established through ox-LDL stimulation, which only provides evidence from one aspect to suggest the functional role of miR-885-5p. The development of ACS is a complex process involving a variety of cells, and it is indeed to assess the function of miR-885-5p in more related cells and pathological processes, such as vascular endothelial cell models, vascular smooth muscle cell models, and inflammatory cell models.

In mechanisms, miRNAs always display functional roles by targeting downstream functional genes. FBXO28, a widely demonstrated cancer regulator in previous studies [41–44], was predicted as a downstream target of miR-885-5p and showed a relatively high binding score. FBXO28 mediates lipid metabolism, which is associated with the onset of ACS, hence, it was hypothesized to mediate the functional role of miR-885-5p. In ox-LDL-induced HCAECs, FBXO28 was negatively regulated by miR-885-5p, and its knockdown could reverse the protective effect of miR-885-5p silencing. Targeting FBXO28 was concluded to be the underlying regulatory mechanism of miR-885-5p in the development of ACS.

Elevated miR-885-5p levels were revealed to be closely associated with the severity of ACS and myocardial injury, which is consistent with previous studies on the regulatory role of non-coding RNAs in cardiovascular pathology. However, several critical challenges hinder the potential clinical translation of miR-885-5p as a clinical biomarker. First, there is a lack of standard process for miRNA detection, which leads to high inter-laboratory and intra-laboratory variability, making it difficult to achieve consistent detection results across clinical centers. Second, the lack of control groups composed of healthy individuals makes it fail to establish reference ranges for miR-885-5p. This uncertainty limits its clinical applicability, as it is impossible to accurately interpret the clinical significance of abnormal expression levels without standardized reference data. Further explorations are indeed with expanding sample size, establishment of standardized analysis processes, and deeper mechanism investigations.

Conclusions

In conclusion, serum miR-885-5p can serve as a promising biomarker for the early screening, severity evaluation, and prognosis assessment of ACS. miR-885-5p could regulate endothelial function by targeting FBXO28 in HCAECs.

Abbreviations

ACS

Acute coronary syndrome

CAD

Coronary artery disease

ELSA

Enzyme-Linked Immunosorbent Assay

HCAECs

Human coronary artery endothelial cells

miRNAs

microRNAs

MACEs

Major adverse cardiovascular events

ROC

Receiver operating characteristic

TEER

Trans-endothelial electrical resistance

Authors’ contributions

Study concept and design: Zheng Zhou and Jingjing Li; analysis and interpretation of data: Xin Liu, Dan Li, Nina Chen and Lushuang Huang; drafting of the manuscript: Lushuang Huang and Nina Chen; critical revision of the manuscript for important intellectual content: Xin Liu, Dan Li and Jingjing Li; statistical analysis: Xin Liu, Dan Li and Jingjing Li.

Funding

This study was funded by Research Project of the Guangdong Provincial Administration of Traditional Chinese Medicine (20251279).

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of The People’s Hospital of Dazu Chongqing (No.2023(005)). Informed consent was obtained from all subjects involved in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.