miR-1290 serves as a potential biomarker for osteoporotic fracture and regulates osteoblast function by targeting KDM5A

Abstract

Objective

This study aims to investigate the expression characteristics, clinical diagnostic value of miR-1290 in osteoporotic fracture (OPF) patients, and its regulatory mechanism in osteoblast function.

Methods

289 subjects were divided into healthy control, OP, and OPF groups. Serum miR-1290 levels were detected by RT-qPCR, and its diagnostic efficacy was evaluated via ROC curve analysis. Functional experiments were conducted using hFOB1.19 cells to explore miR-1290’s expression pattern during osteogenic differentiation and its effects on cell proliferation and differentiation. Bioinformatics prediction, dual-luciferase reporter assay, and RIP assay were used to verify the target gene of miR-1290.

Results

Serum miR-1290 levels showed a gradient decrease from healthy controls to OP and OPF patients. It had favorable diagnostic efficacy for distinguishing OPF from OP patients. OPF patients’ postoperative miR-1290 levels gradually increased. miR-1290 was upregulated during osteogenic differentiation and promoted osteoblast proliferation and differentiation. KDM5A was identified as a direct target of miR-1290, and their expressions were negatively correlated. KDM5A overexpression reversed miR-1290’s enhancement of osteoblast proliferation and differentiation.

Conclusion

miR-1290 is downregulated in OP and OPF patients and promotes osteoblast function by targeting KDM5A, which highlights the role of the miR-1290/KDM5A axis in OPF and offers new insights for clinical diagnosis and targeted therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-026-06734-2.

Introduction

Osteoporosis (OP) is a systemic skeletal disorder characterized by increased bone fragility and elevated risk of pathological fractures [1]. As global aging deepens, approximately 200 million people worldwide are afflicted by this disease [2]. The most severe clinical consequence of OP is fragility fracture, which frequently occurs in weight-bearing areas such as the hip and spine [3]. Among them, hip fractures are linked to a 50% disability rate and a 20% mortality rate, leading to consider medical expenditures annually [4]. Owing to the insidious nature of early osteoporosis symptoms, the majority of patients remain undiagnosed until the first fracture occurs [5]. Consequently, identifying molecular biomarkers for early risk stratification of osteoporosis and fracture prediction, and clarifying the key molecular mechanisms governing bone metabolism and fracture healing, possess significant clinical implications and scientific worth for the early intervention and therapeutic optimization of osteoporosis and osteoporotic fractures (OPF).

In recent years, microRNAs (miRNAs) have been widely implicated in core bone metabolic processes including osteoblast proliferation and differentiation, osteoclast activity regulation, and bone matrix mineralization, through negative regulation of gene expression [6]. The abnormal expression of miRNAs is closely associated with the onset and progression of OP and OPF [7]. For instance, miR-214-3p can impede the healing of osteoporotic fracture, and downregulating its expression may represent a potential intervention strategy for enhancing fracture healing [8]; miR-107 is downregulated in patients with osteoporosis, which not only acts as a reliable biomarker for differentiating OPF from OP but also mitigates bone loss by positively regulating osteogenic processes [9]. Conversely, miR-4534 is upregulated in OPF and participates in disease progression by inhibiting osteoblast function [10]. These studies suggest that different miRNAs play positive or negative regulatory roles in osteoporosis and osteoporotic fractures, providing important clues for investigating the molecular mechanisms of the diseases. Beyond osteoporosis and fracture, miRNAs also critically regulate the repair of tendons and other musculoskeletal tissues by orchestrating extracellular matrix synthesis and inflammatory balance [11]. This broad regulatory role supports the biological plausibility of miR-1290 in bone repair, consistent with miRNAs’ conserved function in tissue homeostasis.

In previous studies, investigators have identified, via miRNA PCR array and next-generation sequencing that miR-1290 is downregulated in female patients with OP and those with severe OP [12, 13]. Moreover, its expression is upregulated in exosomes derived from human bone marrow mesenchymal stem cells (hBMSCs) after chondrogenic induction [14], indicating that miR-1290 may be involved in the regulation of bone metabolism and bone tissue repair processes. Nevertheless, the expression characteristics, diagnostic value of miR-1290 in patients with OPF as well as its specific regulatory effects on osteoblast function, remain unclear and require in-depth investigation to be elucidated.

This research aims to conduct an analysis of the serum expression level of miR-1290 and assess its diagnostic efficacy. Simultaneously, by utilizing hFOB1.19 cells, the study will investigate the expression pattern of miR-1290 during osteogenic differentiation and its impacts on the proliferation and differentiation of osteoblasts, elucidate its role and clinical significance in the disease, and offer novel evidence for early diagnosis and targeted therapy.

Materials and methods

Participants

From May 2021 to August 2023, a total of 289 subjects were recruited from Jinshan Branch Hospital of the Sixth People’s Hospital of Shanghai, comprising 95 healthy individuals, 90 OP patients, and 104 patients with OPF. The specific inclusion criteria for each group are as follows:

1. Healthy individuals: No history of OP, fractures, or diseases influencing bone metabolism, with complete clinical data.

2. Osteoporosis patients without fractures: Bone mineral density (BMD) T-score ≤ −2.5, no history of fractures, no diseases affecting bone metabolism (e.g., malignant tumors, diabetes mellitus, thyroid dysfunction, etc.), no prior use of anti-osteoporosis drugs or medications affecting bone metabolism (such as glucocorticoids), and complete clinical data.

3. Patients with OPF: BMD T-score ≤ −2.5, fragility fractures caused by low-energy trauma (e.g., fractures of the hip, vertebrae, forearm, etc.), fracture occurrence time ≤ 1 week, no multiple fractures or previous fracture history, no severe complications (such as severe infections, liver or kidney failure, etc.), with complete clinical data.

All subjects were excluded if they met any of the following criteria:

1. Suffering from malignant tumors, autoimmune diseases, coagulation disorders, severe liver or kidney insufficiency, or other diseases that affect bone metabolism or experimental results.

2. Recent use (within 3 months) of anti-osteoporosis drugs, glucocorticoids, or hormonal drugs affecting bone metabolism.

3. Pregnant or lactating women.

4. Patients with mental illnesses or those unable to cooperate with the study.

To minimize the influence of the drugs on the serum miR-1290 level, after the surgery, the drug usage was standardized in accordance with clinical guidelines: all patients received basic calcium supplements and vitamin D supplementation, and no additional anti-osteoporosis drugs (such as bisphosphonates, denosumab, or selective estrogen receptor modulators) were used during the short-term follow-up period. The postoperative medication records of all enrolled patients were carefully verified to ensure that there were no significant differences in medication use among patients at different postoperative time points.

Early in the morning following an overnight fast, Peripheral venous blood (5 mL) was collected from all subjects. After being left to stand at room temperature, the blood was centrifuged to separate the serum, which was then stored at −80 °C for subsequent use. In the case of patients with OPF, serum samples were collected at three postoperative time points, namely 1 week, 4 weeks, and 12 weeks after surgery, to monitor the dynamic alterations of miR-1290. A total of 104 OPF patients were recruited for the dynamic monitoring, and 102, 98, and 96 patients completed the follow-up and sample collection at the three respective time points.

This study was conducted in accordance with the principles of the Declaration of Helsinki, and has been approved by the Ethics Committee of Jinshan Branch Hospital of the Sixth People’s Hospital of Shanghai (Ethics Approval No.: LLYJ-KY-2021-001-05). The content and purpose of the study have been fully informed to the patients and their family members, and all patients have signed written informed consent forms.

Cell culture and transfected

To guarantee stable cellular metabolism, the human osteoblast cell line hFOB1.19 was cultured in RPMI-1640 medium within a thermostatic incubator. During the culture process, the medium was refreshed every 2–3 days to sustain the cells in an optimal growth condition.

To prompt the differentiation of hFOB1.19 cells into mature osteoblasts, subsequent to the hFOB1.19 cells seeded in 6-well plates had adhered to the plate, the medium was substituted with osteogenic induction medium (containing 10 mmol/L β-glycerophosphate, 50 µg/mL ascorbic acid, and 10 nmol/L dexamethasone). Cell samples were collected at 0 days, 7 days, and 14 days of induction culture, respectively.

hFOB1.19 cells were inoculated into culture plates and transfected with Lipofectamine 3000 reagent. The groups were classified as follows: (1) Blank control group (Control); (2) Mimic negative control (NC-mimic) group; (3) miR-1290 mimic group; (4) Inhibitor negative control (NC-inhibitor) group; (5) miR-1290 inhibitor group; (6) miR-1290 mimic + oe-NC group; (7) miR-1290 mimic + oe-KDM5A group. Subsequent to transfection, the cells were cultured for 48 h or further incubated until the corresponding time points as stipulated by the experiment for subsequent detection.

RT-qPCR

Total RNA was extracted from serum samples and cell samples using Trizol reagent. Subsequent to passing the quality control, miRNA and mRNA were reverse-transcribed into cDNA using the Mir-X miRNA First-Strand Synthesis Kit and PrimpScript RT Reagent Kit, respectively. PCR amplification was then performed with cDNA as the template. GAPDH and U6 were used as the internal reference genes for mRNA and miRNA, respectively, and the relative expression level of the target gene was calculated using the 2^−ΔΔCt method.

Cell viability assay

The transfected cells were inoculated into culture plates and cultured for 0 h, 24 h, 48 h, and 72 h respectively. At each time point, 10 µL of CCK-8 reagent was introduced to each well. Following incubation in the dark, the absorbance value (OD value) of each well was measured at a wavelength of 450 nm using a microplate reader.

Detection of ALP activity

hFOB1.19 cells were harvested at distinct time points during osteogenic induction or after transfection, and an ALP activity assay kit was employed for detection. The brief procedure is as follows: hFOB1.19 cells were lysed with lysis buffer, and the supernatant was obtained via centrifugation and transferred to a 96-well plate. Subsequently, the working solution, prepared by combining the substrate solution and alkaline buffer was added, was added, followed by thorough homogenization and incubation. Ultimately, the stop solution was added to terminate the enzymatic reaction, and the absorbance value was measured.

Dual-luciferase reporter assay

The binding sites between miR-1290 and KDM5A were predicted using bioinformatics databases including TargetScan, miRDB, and miRWalk. Dual-luciferase reporter plasmids encompassing the wild-type KDM5A (WT-KDM5A) and mutant KDM5A (MUT-KDM5A) were constructed. The constructed plasmids were co-transfected into cells along with miR-1290 mimic or mimic negative control (mimic NC). At 48 h after transfection, the relative luciferase activity was evaluated using a dual-luciferase reporter assay system.

RIP assay

hFOB1.19 cells were lysed using RIP lysis buffer. The cell lysate was incubated overnight with Ago2 antibody or IgG antibody (serving as a negative control), followed by the addition of streptavidin magnetic beads to capture the immunocomplexes. The enrichment levels of miR-1290 and KDM5A were detected by RT-qPCR.

Statistical analysis

Data analysis was performed using SPSS 23.0 and GraphPad Prism 9.0 software. All continuous data were first tested for normality using the Shapiro-Wilk test, and the results confirmed that the data conformed to a normal distribution (P > 0.05). Homogeneity of variance was verified by Levene’s test, showing no significant difference in variance among groups (P > 0.05). For count data, the chi-square test was applied, and the data were presented as n (%). For comparisons between two groups, the independent samples t-test was used; for multiple group comparisons, one-way analysis of variance (ANOVA) was applied followed by Tukey’s post-hoc test to correct for multiple comparisons. Pearson correlation analysis was applied for correlation analysis; receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic efficacy. A P-value < 0.05 was considered statistically significant.

Results

Expression characteristics and clinical diagnostic value of miR-1290

A total of 289 subjects recruited for this study and categorized into three groups: healthy controls, OP patients, and OPF patients. The baseline data of the three groups are presented in Table 1. Evidently, the bone metabolism-related indicators demonstrated significant gradient alterations among the three groups, specifically: 25-hydroxyvitamin D (25-(OH)D) and T-score gradually declined from healthy controls to OP patients and further to OPF patients, with statistically significant differences between groups. Nevertheless, no significant differences were observed among the three groups in smoking, drinking, menopausal status in females, or other aspects.

Table 1.

Clinical baseline characteristics of participants

Items	Participants (n = 289)			P value
	Control (n = 95)	Osteoporosis (n = 90)	Osteoporotic fracture (n = 104)	P a	P b
Age (years)	61.95 ± 5.09	63.20 ± 4.33	62.48 ± 4.05	0.074	0.234
BMI (kg/m2)	23.13 ± 2.57	22.89 ± 2.20	23.43 ± 2.68	0.507	0.137
Sex (female/male)	43/52	49/41	49/55	0.214	0.311
Female postmenopausal status (n, %)	38(88.37)	43(87.76)	44(89.80)	0.928	0.752
Smoking (n, %)	48(50.52)	47(52.22)	44(42.31)	0.819	0.169
Drinking (n, %)	43(45.26)	44(48.90)	46(44.23)	0.624	0.519
25-(OH) vitamin (ng/mL)	38.07 ± 4.94	28.85 ± 3.82	20.43 ± 3.80	< 0.001	< 0.001
Bone density (T score)	−0.04 ± 0.55	−2.87 ± 0.34	−3.17 ± 0.39	< 0.001	< 0.001
Types of fracture
Hip			58
Forearm & wrist			32
Vertebral			3
Other			11

BMI, body mass index; P^a: the P value between the control group and the osteoporosis group; P^b: the P value between the osteoporosis group and the osteoporotic fracture group

Simultaneously, the serum expression of miR-1290 also manifested significant differences: the level was the highest in the healthy control group, notably decreased in the OP group, and further downregulated in the OPF group (P < 0.0001, Fig. 1A). Concerning diagnostic efficacy, the AUC of miR-1290 for differentiating healthy individuals from OP patients was 0.888 (sensitivity: 82.22%, specificity: 84.21%) (Fig. 1B); the AUC for distinguishing OP patients from OPF patients was 0.857 (sensitivity: 84.62%, specificity: 74.44%) (Fig. 1C).

Fig. 1.

Expression and clinical significance of miR-1290. A The levels of miR-1290 in healthy controls (n = 95), OP (n = 90), OPF (n = 104); B–C. Diagnostic efficacy of miR-1290 in distinguishing OP patients from healthy controls, and OPF patients from OP patients; D Dynamic changes in serum miR-1290 expression in OPF patients after surgery. Error bars represent standard deviation (SD). ****P < 0.0001

Moreover, dynamic monitoring of serum miR-1290 levels in OPF patients at different time points after surgery revealed that its level gradually increased with the extension of postoperative time (P < 0.0001, Fig. 1D).

Expression pattern of miR-1290 during osteogenic differentiation of osteoblasts

Following osteogenic induction of hFOB1.19 cells, the relative activity of ALP demonstrated a gradual increase in tandem with the prolongation of induction time (P < 0.0001, Fig. 2A). Analogously, the mRNA expression levels of osteogenic differentiation markers, OCN and Runx2, displayed a time-dependent augmentation (P < 0.0001, Fig. 2B), signifying implementation of osteogenic induction. The expression level of miR-1290 in hFOB1.19 cells exhibited a consistent trend with the aforementioned indicators (P < 0.0001, Fig. 2C), suggesting that miR-1290 may be involved in the regulation of osteogenic differentiation.

Fig. 2.

Expression level of miR-1290 during osteogenic differentiation of osteoblasts. A Relative activity of ALP in osteoblasts at different differentiation time points; B Relative mRNA expression levels of OCN and Runx2; C Dynamic changes in miR-1290 expression in osteoblasts. n = 3 independent experiments, error bars represent SD. ****P < 0.0001

Effects of miR-1290 on the proliferation and differentiation of osteoblasts

Following the transfection of hFOB1.19 cells with miR-1290 inhibitor or mimic respectively, the level of miR-1290 was downregulated or upregulated, indicating successful transfection (P < 0.0001, Fig. 3A). Furthermore, miR-1290 significantly enhanced cell viability (P < 0.0001, Fig. 3B). The relative ALP activity in the miR-1290 mimic group was significantly higher than that in the control group, whereas it was significantly decreased in the miR-1290 inhibitor group (P < 0.0001, Fig. 3C). Simultaneously, the mRNA expression levels of OCN and Runx2 were also significantly upregulated in the miR-1290 mimic group, but significantly downregulated in the miR-1290 inhibitor group (P < 0.0001, Fig. 3D).

Fig. 3.

Effects of miR-1290 on the proliferation and differentiation of osteoblasts. Changes in miR-1290 expression (A), Cell viability (B), ALP activity (C), the levels of OCN and Runx2 (D) after transfection with miR-1290 inhibitor or mimic. n = 3 independent experiments, error bars represent SD. ****P < 0.0001

miR-1290 targets and regulates KDM5A

Bioinformatics prediction, utilizing databases such as TargetScan, miRDB, miRWalk, miRmap, and TarBase, identified KDM5A as a potential target gene of miR-1290 (Fig. 4A), with specific binding sites between the two molecules (Fig. 4B). Dual-luciferase reporter assay indicated that cells co-transfected with miR-1290 mimic and WT-KDM5A plasmid exhibited a notable reduction in relative luciferase activity (P < 0.0001, Fig. 4C). RIP assay demonstrated that the enrichment levels of miR-1290 and KDM5A in the Ago2 antibody group were significantly higher compared to those in the IgG antibody group (P < 0.0001, Fig. 4D). In healthy controls, OP patients, and OPF patients, the mRNA level of KDM5A showed an inverse trend to that of miR-1290 (P < 0.0001, Fig. 4E). Among OPF patients, miR-1290 expression was significantly negatively correlated with KDM5A mRNA expression (r = −0.747, P < 0.0001, Fig. 4F). Dynamic monitoring of OPF patients after surgery and osteogenic induction experiments revealed that KDM5A mRNA expression gradually declined with the prolongation of postoperative or induction time (P < 0.01, Fig. 4G, H). Additionally, transfection with miR-1290 mimic significantly reduced KDM5A mRNA expression (P < 0.0001, Fig. 4I), confirming that miR-1290 can negatively regulate KDM5A expression.

Fig. 4.

miR-1290 targets KDM5A. A Venn diagram of potential target genes predicted by multiple bioinformatics databases; B Schematic diagram of the binding site between miR-1290 and KDM5A; Dual-luciferase reporter assay (C) and RIP assay (D). E Relative mRNA level of KDM5A; F Correlation analysis between miR-1290 and KDM5A mRNA expression; G Dynamic changes in KDM5A mRNA expression in OPF patients after surgery; H Changes in KDM5A mRNA expression during osteogenic differentiation (over time). n = 3 independent experiments, error bars represent SD. **P < 0.01, ****P < 0.0001

Effects of KDM5A overexpression on miR-1290-mediated promotion of osteogenic differentiation

Following transfection with the oe-KDM5A plasmid, the mRNA level of KDM5A in hFOB1.19 cells was significantly increased (P < 0.0001, Fig. 5A). In the miR-1290 mimic + oe-KDM5A co-transfection group, cell viability, ALP activity, and the mRNA expression levels of OCN and Runx2 were all significantly lower than those in the group transfected with miR-1290 mimic alone (P < 0.0001, Fig. 5B–D). These findings imply that KDM5A overexpression can counteract the promotional effects of miR-1290 on osteoblast proliferation and differentiation.

Fig. 5.

Overexpression of KDM5A attenuates miR-1290’s enhancement of osteoblast proliferation and differentiation. Relative KDM5A mRNA levels (A), Cell viability (B), ALP activity (C), relative mRNA levels of OCN and Runx2 (D) in osteoblasts after transfection with miR-1290 mimic or oe-KDM5A plasmid. n = 3 independent experiments, error bars represent SD. ****P < 0.0001

Discussion

OPF is typically characterized by low-energy trauma-induced onset, slow healing, and multiple complications [15]. It commonly occurs in elderly individuals or postmenopausal women, often accompanied by severe pain and limb dysfunction [16]. A significant number of patients necessitate long-term bed rest subsequent to surgery, which predisposes them to severe complications such as pulmonary infections and pressure ulcers. This notably reduces their quality of life and even endanger their lives [17]. Simultaneously, the treatment, rehabilitation, and complication management of fractures consume substantial medical resources, imposing a heavy economic burden on patients’ families and creating a significant social medical burden [18, 19]. More importantly, the early symptoms of osteoporosis are insidious; most patients lack obvious bone pain or functional abnormalities, and their first medical consultation is often triggered by a fracture as the initial manifestation [20]. Moreover, the risk of recurrent fragility fractures increases significantly after the first fracture [21]. Notably, osteoporosis-related disorders such as TBO present clinical challenges with spontaneous pain and bone marrow edema, managed conservatively [22]. This underscores the demand for effective biomarkers and targeted therapies for bone metabolic diseases, highlighting the clinical value of our study on miR-1290 in OPF. Therefore, in-depth analysis of the molecular regulatory network underlying the occurrence and development of OPF, screening for early diagnostic biomarkers with high sensitivity and specificity, and identifying potential molecular targets for targeted therapy are crucial for achieving early warning, precise intervention, and improved prognosis of the disease.

miRNAs, as core molecules in the bone metabolism regulatory network, have offered significant directions for mechanistic investigations into osteoporosis and osteoporotic fractures [23]. For example: miR-181a-5p can markedly facilitate the differentiation of bone marrow mesenchymal stem cells (MSCs) into osteoblasts, while suppressing the formation and activity of osteoclasts, thereby reducing the risk of osteoporosis and related fractures [24]. miR-147b-3p, acting as a crucial positive regulator of osteogenic differentiation, inhibits osteoblast apoptosis and upregulates the expression of osteogenic markers OCN and Runx2 [25]. In the domain of osteoclast regulation and fracture healing, miR-32-3p can enhance the bone resorptive activity of osteoclasts, accelerate bone loss, and thereby elevate the risk of OPF [26]. miR-214-3p delays the healing process of OPF, and downregulating its expression can promote callus formation and mineralization, rendering it a potential intervention strategy for improving fracture healing [8]. In this study, clinical sample detection indicated that the serum expression level of miR-1290 showed a gradient decreasing trend among healthy individuals, OP patients, and OPF patients, with the lowest level observed in the OPF group (lower than that in the OP group). This finding is consistent with previous findings that miR-1290 is downregulated in osteoporosis patients [12, 13]. Meanwhile, miR-1290 demonstrated favorable diagnostic efficacy in differentiating OP patients from OPF patients, implying that miR-1290 could serve as a potential molecular biomarker for identifying OPF. To further confirm its diagnostic value and address the limitations of single indicators, we constructed a combined model of miR-1290 + BMD T-score for this differentiation. The model achieved an AUC of 0.903 (95% CI: 0.859–0.946), with 87.50% sensitivity and 80.00% specificity at the optimal cutoff (Supplementary Fig. 1). Superior to miR-1290 alone (AUC = 0.857), it synergistically improves diagnostic performance by integrating miR-1290’s ability to reflect bone metabolic dynamics and BMD T-score’s advantage in bone mass assessment, effectively overcoming the limitations of single-indicator diagnosis. Notably, current clinical tools have inherent shortcomings: BMD T-score primarily reflects bone mass and fails to capture dynamic metabolic changes or fracture risk in some cases [27], while 25-(OH)D levels are influenced by multiple factors, limiting their specificity for OPF diagnosis [28]. In contrast, miR-1290, involved in core osteoblast regulation and bone repair, shows consistent gradient expression with disease progression, enabling more comprehensive reflection of bone metabolic status and complementary value to existing diagnostics. Consistent with miRNAs’ recognized role as complementary tools in degenerative bone diseases [29], miR-1290 mirrors BTMs (e.g., PINP, CTx) in dynamic postoperative changes [30, 31] but adds direct functional regulation of osteoblasts. Combining miR-1290 with simple clinical indicators (e.g., weight, BMI) [32] or genetic markers (e.g., GLP-1R polymorphisms) [33] could develop convenient OPF risk stratification tools, supported by miRNAs’ proven diagnostic accuracy in other skeletal disorders [34, 35]. Notably, the serum expression level of miR-1290 in OPF patients gradually increased with the progression of postoperative healing, which may correlate with factors associated with postoperative residual low back pain (e.g., low BMD, suboptimal bone cement distribution) [36], offering potential as a biomarker for predicting healing outcomes and guiding intervention. This dynamic change, linked to physiological processes like osteogenic activation and inflammation resolution rather than a single factor, is closely associated with fracture healing. This dynamic change is closely associated with the fracture healing process, implying that miR-1290 may be involved in bone fracture repair and its level could serve as a reference indicator for evaluating postoperative healing outcomes. Notably, postoperative medication was ruled out as a confounding factor for serum miR-1290 levels: patients with prior anti-osteoporosis drug use (within 3 months) were excluded, and postoperative medications were standardized to only calcium and vitamin D supplements with no intergroup differences. Thus, the gradual increase in miR-1290 postoperatively is more likely associated with physiological fracture healing processes (e.g., osteogenic activation, inflammation resolution, bone tissue repair), consistent with in vitro findings that miR-1290 promotes osteoblast proliferation and differentiation, further supporting its role in bone repair. Similarly, other miRNAs such as miR-107 [9] and miR-4534 [10] have also been confirmed to reflect the pathological states of osteoporosis and fractures through changes in their circulating levels, further supporting the clinical potential of miRNAs as diagnostic biomarkers for bone metabolism-related diseases.

Osteoblast dysfunction is a core pathological link in the occurrence of osteoporosis and osteoporotic fractures, and osteogenic differentiation is a key process for osteoblasts to exert their functions [37, 38]. Functional experiments in this study confirmed that miR-1290 can significantly promote osteoblast proliferation and the expression of osteogenic differentiation markers, while inhibiting miR-1290 exerts the opposite effect, indicating that miR-1290 is a positive regulator of osteogenic differentiation. Notably, while miR-1290’s simultaneous promotion of osteoblast proliferation and differentiation may seem contradictory to the conventional view that these processes counterbalance each other, this regulatory pattern is explained by its targeted inhibition of KDM5A. As a histone demethylase, KDM5A epigenetically represses both cell cycle-promoting genes (e.g., cyclin D1, CDK4) and osteogenic transcription factors (e.g., Runx2) [39, 40]. By downregulating KDM5A, miR-1290 concurrently relieves this transcriptional suppression—activating cell cycle genes to boost proliferation and upregulating osteogenic factors to enhance differentiation. This coordinated regulation aligns with previous findings that specific miRNAs can synchronize proliferation and differentiation by targeting key epigenetic regulators [41], further supporting the biological plausibility of our results. This finding is consistent with the functions of other miRNAs that positively regulate osteogenic differentiation, such as miR-181a-5p [24] and miR-147b-3p [25], which enriches the research on the molecular mechanisms of the osteogenic differentiation regulatory network.

To elucidate the molecular mechanism by which miR-1290 regulates osteogenic differentiation, this study employed bioinformatics prediction and experimental validation to confirm that KDM5A is a direct target gene of miR-1290. As a histone H3K4 demethylase, KDM5A exerts its biological functions primarily through regulating the methylation status of H3K4 at the promoter regions of target genes, thereby affecting transcriptional activation. Previous studies have demonstrated that KDM5A is involved in the occurrence and development of osteoporosis by inhibiting bone formation and impeding osteogenic differentiation [39, 41]. Specifically, it can bind to the promoter regions of osteogenic transcription factors (e.g., Runx2) and cell cycle-related genes (e.g., cyclin D1), reducing H3K4me3 levels to repress their transcription [39, 42]. Interfering with KDM5A expression can promote fracture healing in osteoporotic mice [40]. This study found that the mRNA level of KDM5A was significantly negatively correlated with miR-1290 in patients with OPF. Overexpression of KDM5A reversed the promoting effects of miR-1290 on osteoblast proliferation and differentiation, which led us to speculate that the miR-1290/KDM5A axis regulates osteogenesis through the following epigenetic mechanism: miR-1290 inhibits KDM5A, which reduces the demethylation activity of H3K4 at the promoter regions of osteogenic genes (e.g., Runx2, OCN) and cell cycle-promoting genes. The subsequent increase in H3K4me3 levels enhances the transcriptional activation of these genes, thereby synergistically promoting osteoblast proliferation and osteogenic differentiation. This regulatory pattern is in line with the well-documented role of KDM5A in bone metabolism, and similar to the mechanisms by which other miRNAs (e.g., miR-214-3p) regulate bone metabolism by targeting specific pathways or genes [8, 26, 43]. It reflects the common rule that miRNAs regulate bone metabolism by targeting specific pathways or genes, and also provides a new molecular target for the targeted therapy of OPF. Like other bone-regulating miRNAs (e.g., miR-217 targeting OPG/RANKL/RANK [44], miR-204-5p modulating NF-κB) [45], miR-1290 exerts osteogenic effects by targeting a key epigenetic regulator (KDM5A). This confirms miRNAs’ conserved role in bone metabolism—targeting critical pathways/genes to modulate osteoblast function—strengthening our mechanism findings.

This study has several limitations. First, while U6 (a common internal reference for circulating miRNAs) was validated as stable across groups, its controversial stability in serum/plasma may affect relative expression reliability; future studies could use multiple reference genes (e.g., miR-16, let-7a) or external controls to enhance robustness. Second, as a single-center exploratory study with a limited sample size, we did not compare miR-1290 directly with existing clinical indicators (e.g., BMD T-score, 25-(OH)D) or construct a combined diagnostic model, so its generalizability requires multi-center validation. Third, functional experiments were limited to hFOB1.19 cells; in vivo verification using osteoporotic fracture animal models is needed, referencing non-coding RNA-based tissue repair strategies [46]. Finally, the specific epigenetic modifications of osteogenic genes mediated by KDM5A require further exploration, and future studies could investigate miR-1290’s synergistic regulatory networks with circRNAs/lncRNAs [47–49] to enrich the molecular mechanism map.

In conclusion, this study confirms that miR-1290 is downregulated in patients with OP and OPF, and it can serve as a potential biomarker for disease diagnosis and postoperative healing evaluation. miR-1290 promotes osteoblast proliferation and differentiation by targeting and inhibiting KDM5A expression, thereby participating in the regulation of bone metabolism and the process of fracture repair. Notably, siRNAs show promise for osteoporosis therapy [50], and the miR-1290/KDM5A axis offers a novel target referencing their delivery strategies. With modern osteoporosis management emphasizing personalization—variable antiresorptive efficacy [51] and genetic modulation of responses [52]—the axis complements conventional drugs [53, 54] and addresses OPF challenges (debated vertebroplasty [55], natural compound pathways [56]) via epigenetic regulation, broadening personalized treatment options. This finding not only reveals the role and mechanism of the miR-1290/KDM5A axis in OPF but also provides new insights and experimental evidence for the clinical diagnosis and targeted therapy of the disease.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

Conceptualization, Q.C., W.L., W.C.; Data curation, Q.C., W.L., W.C.; Formal analysis, X.Q.X., J.H., X.J.Z., Q.C., W.L., W.C.; Funding acquisition, W.C.; Investigation, Q.C., W.L.; Methodology, X.Q.X., J.H., X.J.Z., Q.C., W.L., W.C.; Project administration, X.J.Z., W.C.; Resources, Q.C., W.L.; Software, Q.C., W.L.; Supervision, X.J.Z., W.C.; Validation, X.Q.X., J.H., X.J.Z., W.L.; Visualization, Q.C.; Roles/Writing—original draft, Q.C.; Writing—review & editing, X.Q.X., J.H., X.J.Z., W.C.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Data availability

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

Declarations

Ethics approval

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of Jinshan Branch Hospital of the Sixth People’s Hospital of Shanghai.

Consent to participate

Informed consent was obtained from all individual participants included in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Clinical trial number

Not applicable.