Dysregulated circRNAs in plasma from active tuberculosis patients

Endogenous circular RNAs (circRNAs) have been reported in various diseases. However, their role in active TB remains unknown. The study was aimed to determine plasma circRNA expression profile to characterize potential biomarker and improve our understanding of active TB pathogenesis. CircRNA expression profiles were screened by circRNA microarrays in active TB plasma samples. Dysregulated circRNAs were then verified by qRT‐PCR. CircRNA targets were predicted based on analysis of circRNA‐miRNA‐mRNA interaction. GO and KEGG pathway analyses were used to predict the function of circRNA. ROC curve was calculated to evaluate diagnostic value for active TB. A total of 75 circRNAs were significantly dysregulated in active TB plasma. By further validation, hsa_circRNA_103571 exhibited significant decrease in active TB patients and showed potential interaction with active TB‐related miRNAs such as miR‐29a and miR‐16. Bioinformatics analysis revealed that hsa_circRNA_103571 was primarily involved in ras signalling pathway, regulation of actin cytoskeleton, T‐ and B‐cell receptor signalling pathway. ROC curve analysis suggested that hsa_circRNA_103571 had significant value for active TB diagnosis. Circulating circRNA dysregulation may play a role in active TB pathogenesis. Hsa_circRNA_103571 may be served as a potential biomarker for active TB diagnosis, and hsa_circRNA_103571‐miRNA‐mRNA interaction may provide some novel mechanism for active TB.     

Induced miR‐99a expression represses Mtor cooperatively with miR‐150 to promote regulatory T‐cell differentiation

Peripheral induction of regulatory T (Treg) cells provides essential protection from inappropriate immune responses. CD4⁺ T cells that lack endogenous miRNAs are impaired to differentiate into Treg cells, but the relevant miRNAs are unknown. We performed an overexpression screen with T‐cell‐expressed miRNAs in naive mouse CD4⁺ T cells undergoing Treg differentiation. Among 130 candidates, the screen identified 29 miRNAs with a negative and 10 miRNAs with a positive effect. Testing reciprocal Th17 differentiation revealed specific functions for miR‐100, miR‐99a and miR‐10b, since all of these promoted the Treg and inhibited the Th17 program without impacting on viability, proliferation and activation. miR‐99a cooperated with miR‐150 to repress the expression of the Th17‐promoting factor mTOR. The comparably low expression of miR‐99a was strongly increased by the Treg cell inducer “retinoic acid”, and the abundantly expressed miR‐150 could only repress Mtor in the presence of miR‐99a. Our data suggest that induction of Treg cell differentiation is regulated by a miRNA network, which involves cooperation of constitutively expressed as well as inducible miRNAs.     

MicroRNA Profile of Tumorigenic Cells During Carcinogenesis of Lung Adenocarcinoma

To obtain microRNA (miRNA) profile and clarify their biological function in tumorigenic Sca‐1⁺CD34⁺ cells during carcinogenesis of lung adenocarcinoma. After intranasal infection with recombinant Adeno‐Cre viruses (AdV‐Cre), lung adenocarcinoma was identified pathologically in Lox‐stop‐lox Kras (LSL‐Kras) G12D mice. Sca‐1⁺CD34⁺ cells were sorted by flow cytometry and tested for tumor‐initiating ability, self‐renewal and tumorigenicity. MiRNA profiles were obtained using microarray and further confirmed by real‐time RT‐PCR (qRT‐PCR). MiRNA functions were predicted bioinformatically, and miR‐294 function was verified to explore its role in tumor migration and invasion. Lung adenocarcinoma was induced in LSL‐Kras G12D mice within 30 days. In vivo, the tumorigenicity of Sca‐1⁺CD34⁺ cells was 25 times stronger than Sca‐1^?CD34^? cells. During tumorigenesis of lung adenocarcinoma, the expression of 145 miRNAs in Sca‐1⁺CD34⁺ cells increased and 72 miRNAs decreased (P < 0.01). Four successively up‐regulated miRNAs (miR‐15a*, miR‐203, miR‐294 and miR‐295*) and three successively down‐regulated ones (miR‐19b, miR‐483 and miR‐615–5p) were identified. Among them, miR‐294 could constitutively bind to 3'‐UTR of matrix metalloproteinase 3 (MMP3), and down‐regulate MMP3 protein expression. MiR‐294 also significantly inhibited migration and invasion of Lewis lung cancer cells. MiRNAs are characteristically expressed in tumor‐initiating Sca‐1⁺CD34⁺ cells of lung adenocarcinoma, and may play important roles during the carcinogenesis of lung adenocarcinoma. J. Cell. Biochem. 116: 458–466, 2015. © 2014 The Authors. Journal of Cellular Biochemistry published by Wiley Periodicals, Inc.

     

Identification of HLA‐A*11:01‐restricted Mycobacterium tuberculosis CD8+ T cell epitopes

New vaccines are needed to combat Mycobacterium tuberculosis (MTB) infections. The currently employed Bacillus Calmette‐Guérin vaccine is becoming ineffective, due in part to the emergence of multidrug‐resistant tuberculosis (MDR‐TB) strains and the reduced immune capacity in cases of HIV coinfection. CD8⁺ T cells play an important role in the protective immunity against MTB infections, and the identification of immunogenic CD8⁺ T cell epitopes specific for MTB is essential for the design of peptide‐based vaccines. To identify CD8⁺ T cell epitopes of MTB proteins, we screened a set of 94 MTB antigens for HLA class I A*11:01‐binding motifs. HLA‐A*11:01 is one of the most prevalent HLA molecules in Southeast Asians, and definition of T cell epitopes it can restrict would provide significant coverage for the Asian population. Peptides that bound with high affinity to purified HLA molecules were subsequently evaluated in functional assays to detect interferon‐γ release and CD8⁺ T cell proliferation in active pulmonary TB patients. We identified six novel epitopes, each derived from a unique MTB antigen, which were recognized by CD8⁺ T cells from active pulmonary TB patients. In addition, a significant level of epitope‐specific T cells could be detected ex vivo in peripheral blood mononuclear cells from active TB patients by an HLA‐A*11:01 dextramer carrying the peptide Rv3130c_194‐204 (from the MTB triacylglycerol synthase Tgs1), which was the most frequently recognized epitope in our peptide library. In conclusion, this study identified six dominant CD8⁺ T cell epitopes that may be considered potential targets for subunit vaccines or diagnostic strategies against TB.     

MicroRNA‐126 regulates the induction and function of CD4+ Foxp3+ regulatory T cells through PI3K/AKT pathway

Recent evidence showed that limited activation of PI3K/Akt pathway was critical for induction and function sustainment of CD4⁺Foxp3⁺ regulatory T cells (Tregs). However, the underlying mechanism remains largely unknown. In this study, we reported that miR‐126 was expressed in mouse and human Tregs. Further study showed that silencing of miR‐126 using miR‐126 antisense oligonucleotides (ASO) could significantly reduce the induction of Tregs in vitro. Furthermore, miR‐126 silencing could obviously reduce the expression of Foxp3 on Tregs, which was accompanied by decreased expression of CTLA‐4 and GITR, as well as IL‐10 and TGF‐β, and impair its suppressive function. Mechanistic evidence showed that silencing of miR‐126 enhanced the expression of its target p85β and subsequently altered the activation of PI3K/Akt pathway, which was ultimately responsible for reduced induction and suppressive function of Tregs. Finally, we further revealed that miR‐126 silencing could impair the suppressive function of Tregs in vivo and endow effectively antitumour effect of CD8⁺T cells in adoptive cell transfer assay using a murine breast cancer model. Therefore, our study showed that miR‐126 could act as fine‐tuner in regulation of PI3K‐Akt pathway transduction in the induction and sustained suppressive function of Tregs and provided a novel insight into the development of therapeutic strategies for promoting T‐cell immunity by regulating Tregs through targeting specific miRNAs.     

Identification of miR‐93 as a suitable miR for normalizing miRNA in plasma of tuberculosis patients

Tuberculosis (TB) remains a major public health issue. New tests to aid diagnoses and monitor the response to therapy are urgently required. There is growing interest in the use of microRNA (miRNA) profiles as diagnostic, prognostic or predictive markers in a range of clinical and infectious diseases, including Mycobacterium tuberculosis infection, however, challenges exist to accurately normalise miRNA levels in cohorts. This study examined the appropriateness of 12 miRs and RNU6B to normalise circulating plasma miRNA levels in individuals with active TB from 2 different geographical and ethnic regions. Twelve miRs (let‐7, miR‐16, miR‐22, miR‐26, miR‐93, miR‐103, miR‐191, miR‐192, miR‐221, miR‐423, miR‐425 and miR‐451) and RNU6B were selected based on their reported production by lung cells, expression in blood and previous use as a reference miRNA. Expression levels were analysed in the plasma of newly diagnosed TB patients from Australia and China compared with individuals with latent TB infection and healthy volunteers. Analysis with both geNorm and NormFinder software identified miR‐93 as the most suitable reference miR in both cohorts, either when analysed separately or collectively. Interestingly, there were large variations in the expression levels of some miRs, in particular miR‐192 and let‐7, between the two cohorts, independent of disease status. These data identify miR‐93 is a suitable reference miR for normalizing miRNA levels in TB patients, and highlight how environmental, and possibly ethnic, factors influence miRNA expression levels, demonstrating the necessity of assessing the suitability of reference miRs within the study population.     

Involvement of CD244 in Regulating CD4+ T Cell Immunity in Patients with Active Tuberculosis

CD244 (2B4) is a member of the signaling lymphocyte activation molecule (SLAM) family of immune cell receptors and it plays an important role in modulating NK cell and CD8⁺ T cell immunity. In this study, we investigated the expression and function of CD244/2B4 on CD4⁺ T cells from active TB patients and latent infection individuals. Active TB patients had significantly elevated CD244/2B4 expression on M. tuberculosis antigen-specific CD4⁺ T cells compared with latent infection individuals. The frequencies of CD244/2B4-expressing antigen-specific CD4⁺ T cells were significantly higher in retreatment active TB patients than in new active TB patients. Compared with CD244/2B4-dull and -middle CD4⁺ T cells, CD244/2B4-bright CD4⁺ T cell subset had significantly reduced expression of IFN-γ, suggesting that CD244/2B4 expression may modulate IFN-γ production in M. tuberculosis antigen-responsive CD4⁺ T cells. Activation of CD244/2B4 signaling by cross-linking led to significantly decreased production of IFN-γ. Blockage of CD244/2B4 signaling pathway of T cells from patients with active TB resulted in significantly increased production of IFN-γ, compared with isotype antibody control. In conclusion, CD244/2B4 signaling pathway has an inhibitory role on M. tuberculosis antigen-specific CD4⁺ T cell function.     

Down‐expression of miR‐154 suppresses tumourigenesis in CD133+ glioblastoma stem cells

Glioblastoma multiforme (GBM) is the most common and aggressive form of brain cancer. Evidences have suggested that CD133 is a marker for a subset of glioblastoma cancer stem cells. However, whether miRNA plays a critical role in CD133⁺ GBM is poorly understood. Here, we identified that miR‐154 was upregulated in CD133⁺ GBM cell lines. Knockdown of miR‐154 remarkably suppressed proliferation and migration of CD133⁺ GBM cells. Further study found that PRPS1 was a direct target of miR‐154 in CD133⁺ GBM cells. Overexpression of PRPS1 exhibited similar effects as miR‐154 knockdown in CD133⁺ GBMs. Our study identified miR‐154 as a previously unrecognized positive regulator of proliferation and migration in CD133⁺ GBM cells and a potentially therapeutic target of GBMs. Copyright © 2016 John Wiley & Sons, Ltd.     

MiR‐16 regulates mouse peritoneal macrophage polarization and affects T‐cell activation

MiR‐16 is a tumour suppressor that is down‐regulated in certain human cancers. However, little is known on its activity in other cell types. In this study, we examined the biological significance and underlying mechanisms of miR‐16 on macrophage polarization and subsequent T‐cell activation. Mouse peritoneal macrophages were isolated and induced to undergo either M1 polarization with 100 ng/ml of interferon‐γ and 20 ng/ml of lipopolysaccharide, or M2 polarization with 20 ng/ml of interleukin (IL)‐4. The identity of polarized macrophages was determined by profiling cell‐surface markers by flow cytometry and cytokine production by ELISA. Macrophages were infected with lentivirus‐expressing miR‐16 to assess the effects of miR‐16. Effects on macrophage–T cell interactions were analysed by co‐culturing purified CD4⁺ T cells with miR‐16‐expressing peritoneal macrophages, and measuring activation marker CD69 by flow cytometry and cytokine secretion by ELISA. Bioinformatics analysis was applied to search for potential miR‐16 targets and understand its underlying mechanisms. MiR‐16‐induced M1 differentiation of mouse peritoneal macrophages from either the basal M0‐ or M2‐polarized state is indicated by the significant up‐regulation of M1 marker CD16/32, repression of M2 marker CD206 and Dectin‐1, and increased secretion of M1 cytokine IL‐12 and nitric oxide. Consistently, miR‐16‐expressing macrophages stimulate the activation of purified CD4⁺ T cells. Mechanistically, miR‐16 significantly down‐regulates the expression of PD‐L1, a critical immune suppressor that controls macrophage–T cell interaction and T‐cell activation. MiR‐16 plays an important role in shifting macrophage polarization from M2 to M1 status, and functionally activating CD4⁺ T cells. This effect is potentially mediated through the down‐regulation of immune suppressor PD‐L1.     

Endoplasmic reticulum stress‐induced exosomal miR‐27a‐3p promotes immune escape in breast cancer via regulating PD‐L1 expression in macrophages

Immune escape of breast cancer cells contributes to breast cancer pathogenesis. Tumour microenvironment stresses that disrupt protein homeostasis can produce endoplasmic reticulum (ER) stress. The miRNA‐mediated translational repression of mRNAs has been extensively studied in regulating immune escape and ER stress in human cancers. In this study, we identified a novel microRNA (miR)‐27a‐3p and investigated its mechanistic role in promoting immune evasion. The binding affinity between miR‐27a‐3p and MAGI2 was predicted using bioinformatic analysis and verified by dual‐luciferase reporter assay. Ectopic expression and inhibition of miR‐27a‐3p in breast cancer cells were achieved by transduction with mimics and inhibitors. Besides, artificial modulation of MAGI2 and PTEN was done to explore their function in ER stress and immune escape of cancer cells. Of note, exosomes were derived from cancer cells and co‐cultured with macrophages for mechanistic studies. The experimental data suggested that ER stress biomarkers including GRP78, PERK, ATF6, IRE1α and PD‐L1 were overexpressed in breast cancer tissues relative to paracancerous tissues. Endoplasmic reticulum stress promoted exosome secretion and elevated exosomal miR‐27a‐3p expression. Elevation of miR‐27a‐3p and PD‐L1 levels in macrophages was observed in response to exosomes‐overexpressing miR‐27a‐3p in vivo and in vitro. miR‐27a‐3p could target and negatively regulate MAGI2, while MAGI2 down‐regulated PD‐L1 by up‐regulating PTEN to inactivate PI3K/AKT signalling pathway. Less CD4⁺, CD8⁺ T cells and IL‐2, and T cells apoptosis were observed in response to co‐culture of macrophages and CD3⁺ T cells. Conjointly, exosomal miR‐27a‐3p promotes immune evasion by up‐regulating PD‐L1 via MAGI2/PTEN/PI3K axis in breast cancer.     

Cellular and extracellular miRNAs are blood‐compartment‐specific diagnostic targets in sepsis

Septic shock is a common medical condition with a mortality approaching 50% where early diagnosis and treatment are of particular importance for patient survival. Novel biomarkers that serve as prompt indicators of sepsis are urgently needed. High‐throughput technologies assessing circulating microRNAs represent an important tool for biomarker identification, but the blood‐compartment specificity of these miRNAs has not yet been investigated. We characterized miRNA profiles from serum exosomes, total serum and blood cells (leukocytes, erythrocytes, platelets) of sepsis patients by next‐generation sequencing and RT‐qPCR (n = 3 × 22) and established differences in miRNA expression between blood compartments. In silico analysis was used to identify compartment‐specific signalling functions of differentially regulated miRNAs in sepsis‐relevant pathways. In septic shock, a total of 77 and 103 miRNAs were down‐ and up‐regulated, respectively. A majority of these regulated miRNAs (14 in serum, 32 in exosomes and 73 in blood cells) had not been previously associated with sepsis. We found a distinctly compartment‐specific regulation of miRNAs between sepsis patients and healthy volunteers. Blood cellular miR‐199b‐5p was identified as a potential early indicator for sepsis and septic shock. miR‐125b‐5p and miR‐26b‐5p were uniquely regulated in exosomes and serum, respectively, while one miRNA (miR‐27b‐3p) was present in all three compartments. The expression of sepsis‐associated miRNAs is compartment‐specific. Exosome‐derived miRNAs contribute significant information regarding sepsis diagnosis and survival prediction and could serve as newly identified targets for the development of novel sepsis biomarkers.     

Human herpesvirus-6-specific interleukin 10-producing CD4+ T cells suppress the CD4+ T-cell response in infected individuals

Human herpesvirus‐6 (HHV‐6) infection normally persists for the lifetime of the host and may reactivate with immunosuppression. The mechanism behind HHV‐6 latent infection is still not fully understood. In this study, we observed that decreased proliferation of CD4⁺ T cells and PBMCs but not CD8⁺ T cells from HHV‐6‐infected individuals was stimulated with HHV‐6‐infected cell lysates. Moreover, HHV‐6‐stimulated CD4⁺ T cells from HHV‐6‐infected individuals have suppressive activity on naïve CD4⁺ T and CD8⁺ T cells from HHV‐6‐uninfected individuals. However, no increased proportion of CD4⁺ CD25⁺ Treg cells from HHV‐6‐infected individuals contributed to the suppressive activity of the HHV‐6‐stimulated CD4⁺ T cells from HHV‐6‐infected individuals. Transwell experiments, ELISA and anti‐IL‐10 antibody blocking experiment demonstrated that IL‐10 may be the suppressive cytokine required for suppressive activity of CD4⁺ T cells from HHV‐6‐infected individuals. Results of intracellular interleukin (IL)‐10 and IL‐4 further implicated the HHV‐6‐speciflc IL‐10‐producing CD4⁺ T cells in the suppressive activity of CD4⁺ T cells from HHV‐6‐infected individuals. Results of intracellular interferon (IFN)‐γ demonstrated a decreased frequency of HHV‐6‐speciflc IFN‐γ‐producing CD4⁺ T, but not CD8⁺ T cells in HHV‐6‐infected individuals, indicating that it was the CD4⁺ Th1 responses in HHV‐6‐infected individuals that were selectively impaired. Our findings indicated that HHV‐6‐specific IL‐10‐producing CD4⁺ T cells from HHV‐6‐infected individuals possess T regulatory type 1 cell activity: immunosuppression, high levels of IL‐10 production, with a few cells expressing IFN‐γ, but none expressing IL‐4. These cells may play an important role in latent HHV‐6 infection.     

Identification of micro‐RNA networks in end‐stage heart failure because of dilated cardiomyopathy

Micro‐RNAs regulate gene expression by directly binding to the target mRNAs. The goal of the study was to examine the expression profiling of miRNAs in human failing hearts and identify the key miRNAs that regulate molecular signalling networks and thus contribute to this pathological process. The levels of miRNAs and expressed genes were analysed in myocardial biopsy samples from patients with end‐stage heart failure (n = 14) and those from normal heart samples (n = 8). Four networks were built including the Gene regulatory network, Signal‐Network, miRNA‐GO‐Network and miRNA‐Gene‐Network. According to the fold change in the network and probability values in the microarray cohort, RT‐PCR was performed to measure the expression of five of the 72 differentially regulated miRNAs. miR‐340 achieved statistically significant. miR‐340 was identified for the first time in cardiac pathophysiological condition. We overexpressed miR‐340 in cultured neonatal rat cardiomyocytes to identify whether miR‐340 plays a determining role in the progression of heart failure. ANP, BNP and caspase‐3 were significantly elevated in the miR‐340 transfected cells compared with controls (P < 0.05). The cross‐sectional area of overexpressing miR‐340 cardiomyocytes (1952.22 ± 106.59) was greater (P < 0.0001) than controls (1059.99 ± 45.59) documented by Laser Confocal Microscopy. The changes of cellular structure and the volume were statistical significance. Our study provided a comprehensive miRNA expression profiling in the end‐stage heart failure and identified miR‐340 as a key miRNA contributing to the occurrence and progression of heart failure. Our discoveries provide novel therapeutic targets for patients with heart failure.     

Human CD8+CD25 +CD127 low regulatory T cells: microRNA signature and impact on TGF-β and IL-10 expression

Regulatory T cells (Tregs) are central for maintaining immune balance and their dysfunction drives the expansion of critical immunologic disorders. During the past decade, microRNAs (miRNAs) have emerged as potent regulators of gene expression among which immune-related genes and their immunomodulatory properties have been associated with different immune-based diseases. The miRNA signature of human peripheral blood (PB) CD8⁺CD25 ⁺CD127 ^low Tregs has not been described yet. We thus identified, using TaqMan low-density array (TLDA) technique followed by individual quantitative real-time polymerase chain reaction (qRT-PCR) confirmation, 14 miRNAs, among which 12 were downregulated whereas two were upregulated in CD8 ⁺CD25 ⁺CD127 ^low Tregs in comparison to CD8 ⁺CD25 ⁻ T cells. In the next step, microRNA Data Integration Portal (mirDIP) was used to identify potential miRNA target sites in the 3′-untranslated region (3′-UTR) of key Treg cell-immunomodulatory genes with a special focus on interleukin 10 (IL-10) and transforming growth factor β (TGF-β). Having identified potential miR target sites in the 3′-UTR of IL-10 (miR-27b-3p and miR-340-5p) and TGF-β (miR-330-3p), we showed through transfection and transduction assays that the overexpression of two underexpressed miRNAs, miR-27b-3p and miR-340-5p, downregulated IL-10 expression upon targeting its 3′-UTR. Similarly, overexpression of miR-330-3p negatively regulated TGF-β expression. These results highlighted an important impact of the CD8 ⁺ Treg mirnome on the expression of genes with significant implication on immunosuppression. These observations could help in better understanding the mechanism(s) orchestrating Treg immunosuppressive function toward unraveling new targets for treating autoimmune pathologies and cancer.     

Circulating microRNA signature of steroid‐induced osteonecrosis of the femoral head

Objectives

Steroid‐induced osteonecrosis of the femoral head (ONFH) is a common orthopaedic disease of which early detection remains clinically challenging. Accumulating evidences indicated that circulating microRNAs (miRNAs) plays vital roles in the development of several bone diseases. However, the association between circulating miRNAs and steroid‐induced ONFH remains elusive.

Materials and methods

miRNA microarray was performed to identify the differentially abundant miRNAs in the serums of systemic lupus erythematosus (SLE) patients with steroid‐induced ONFH as compared with SLE control and healthy control group. We predicted the potential functions of these differentially abundant miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and reconstructed the regulatory networks of miRNA‐mRNA interactions.

Results

Our data indicated that there were 11 differentially abundant miRNAs (2 upregulated and 9 downregulated) between SLE‐ONFH group and healthy control group and 42 differentially abundant miRNAs (14 upregulated and 28 downregulated) between SLE‐ONFH group and SLE control group. We also predicted the potential functions of these differentially abundant miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and reconstructed the regulatory networks of miRNA‐mRNA interactions.

Conclusions

These findings corroborated the idea that circulating miRNAs play significant roles in the development of ONFH and may serve as diagnostic markers and therapeutic targets.     

MicroRNA expression profile of human periodontal ligament cells under the influence of Porphyromonas gingivalis LPS

Periodontitis is a chronic inflammatory disease which is caused by bacterial infection and leads to the destruction of periodontal tissues and resorption of alveolar bone. Thus, special attention should be paid to the mechanism under lipopolysaccharide (LPS)‐induced periodontitis because LPS is the major cause of periodontitis. However, to date, miRNA expression in the LPS‐induced periodontitis has not been well characterized. In this study, we investigated miRNA expression patterns in LPS‐treated periodontal ligament cells (PDLCs). Through miRNA array and differential analysis, 22 up‐regulated miRNAs and 28 down‐regulated miRNAs in LPS‐treated PDLCs were identified. Seven randomly selected up‐regulated (miR‐21‐5p, 498, 548a‐5p) and down‐regulated (miR‐495‐3p, 539‐5p, 34c‐3p and 7a‐2‐3p) miRNAs were examined by qRT‐PCR, and the results proved the accuracy of the miRNA array. Moreover, targets of these deregulated miRNAs were analysed using the miRWalk database. Database for Annotation, Visualization and Integration Discovery software were performed to analyse the Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes pathway of differential expression miRNAs, and the results shown that Toll‐like receptor signalling pathway, cAMP signalling pathway, transforming growth factor‐beta signalling pathway, mitogen‐activated protein kinase (MAPK) signalling pathway and other pathways were involved in the molecular mechanisms underlying LPS‐induced periodontitis. In conclusion, this study provides clues for enhancing our understanding of the mechanisms and roles of miRNAs as key regulators of LPS‐induced periodontitis.