microRNAs: Emerging players in oral cancers and inflammatory disorders

Gene expression analysis of microRNA-1285 in the South Indian oral squamous cell carcinoma population

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most common oral malignant tumor, which has poor prognosis. The traditional investigative modality is invasive biopsy which is the gold standard for diagnosis. In recent years, alternative methods like non-invasive biomarkers have been studied for their potential role in early diagnosis and prognosis. Among them, microRNAs (miRNAs or miRs) are short non-coding RNAs that regulate gene expression in various diseases, including OSCC. Several miRNAs are being researched as non-invasive biomarkers as well as novel therapeutic targets in the treatment of OSCC. MiR expression can be upregulated or downregulated in OSCC. Among the reported miRNAs, miR-1285 is an important miRNA found to be involved in OSCC. The aim of the current study was to quantify the levels of miR-1285 in OSCC samples and to validate their potential role as biomarkers for OSCC detection.

METHODS

Sixteen samples of cancer tissue and normal tissue were evaluated from a total of 25 patients, in the study, conducted in the Department of Oral and Maxillofacial Surgery. The tissues were processed for H&E staining and gene expression analysis of miR-1285. The samples were collected after proper informed consent from the patients. Total RNA isolated was reverse transcribed into cDNA which was used in the gene expression analysis using qRT-PCR.

RESULTS

The histopathological examination confirmed the OSCC cases and the gene expression analysis revealed that miR-1285 was significantly downregulated in OSCC tissues. Since miR-1285 showed significant difference between the OSCC and normal tissues it could be postulated as a potential biomarker and therapeutic target for OSCC.

CONCLUSIONS

Further in-vitro and in-vivo studies could validate their functional role in OSCC.

Noncoding RNAs in oral cancer

Oral cancer (OC) is the most prevalent subtype of cancer arising in the head and neck region. OC risk is mainly attributed to behavioral risk factors such as exposure to tobacco and excessive alcohol consumption, and a lesser extent to viral infections such as human papillomaviruses and Epstein-Barr viruses. In addition to these acquired risk factors, heritable genetic factors have shown to be associated with OC risk. Despite the high incidence, biomarkers for OC diagnosis are lacking and consequently, patients are often diagnosed in advanced stages. This delay in diagnosis is reflected by poor overall outcomes of OC patients, where 5-year overall survival is around 50%. Among the biomarkers proposed for cancer detection, noncoding RNA (ncRNA) can be considered as one of the most promising categories of biomarkers due to their role in virtually all cellular processes. Similar to other cancer types, changes in expressions of ncRNAs have been reported in OC and a number of ncRNAs have diagnostic, prognostic, and therapeutic potential. Moreover, some ncRNAs are capable of regulating gene expression by various mechanisms. Therefore, elucidating the current literature on the four main types of ncRNAs namely, microRNA, lncRNA, snoRNA, piwi-RNA, and circular RNA in the context of OC pathogenesis is timely and would enable further improvements and innovations in diagnosis, prognosis, and treatment of OC. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Dynamic Changes in Macrophage Polarization during the Resolution Phase of Periodontal Disease

Periodontal inflammation is largely governed by infiltration of myeloid cells, in particular macrophages. Polarization of Mφ within the gingival tissues is a well-controlled axis and has considerable consequences for how Mφ participate in inflammatory and resolution (tissue repair) phases. We hypothesize that periodontal therapy may instigate a pro-resolution environment favoring M2 Mφ polarization and contribute towards resolution of inflammation post-therapy. We aimed to evaluate the markers of macrophage polarization before and after periodontal therapy. Gingival biopsies were excised from human subjects with generalized severe periodontitis, undergoing routine non-surgical therapy. A second set of biopsies were excised after 4-6 weeks to assess the impact of therapeutic resolution at the molecular level. As controls, gingival biopsies were excised from periodontally healthy subjects, undergoing crown lengthening. Total RNA was isolated from gingival biopsies to evaluate pro- and anti-inflammatory markers associated with macrophage polarization by RT-qPCR. Mean periodontal probing depths, CAL and BOP reduced significantly after therapy and corroborated with the reduced levels of periopathic bacterial transcripts after therapy. Compared to heathy and treated biopsies, higher load of Aa and Pg transcripts were observed in disease. Lower expression of M1Mφ markers (TNF-α, STAT1) were observed after therapy as compared to diseased samples. Conversely, M2Mφ markers (STAT6, IL-10) were highly expressed in post-therapy as opposed to pre-therapy, which correlated with clinical improvement. These findings corroborated with murine ligature-induced periodontitis and resolution model, comparing the respective murine Mφ polarization markers (M1 Mφ: cox2 , iNOS2 and M2 Mφ: tgm2 and arg1 ). Our findings suggest that imbalance in M1 and M2 polarized macrophages by assessment of their markers can provide relevant clinical information on the successful response of periodontal therapy and can be used to target non-responders with exaggerated immune responses.

Tumor Suppressor miRNA-503 Inhibits Cell Invasion in Head and Neck Cancer through the Wnt Signaling Pathway via the WNT3A/MMP Molecular Axis

Head and neck cancer (HNC) is the fifth most common cancer worldwide, and its incidence and death rates have been consistently high throughout the past decades. MicroRNAs (miRNAs) have recently gained significant attention because of their role in the regulation of a variety of biological processes via post-transcriptional silencing mechanisms. Previously, we determined a specific profile of miRNAs associated with HNC using a miRNA microarray analysis. Of the 23 miRNAs with highly altered expression in HNC cells, miR-503 was the most significantly downregulated miRNA. In this study, we confirmed that miR-503 acts as a tumor suppressor, as our results showed decreased levels of miR-503 in cancer cells and patients with HNC. We further characterized the role of miR-503 in the malignant functions of HNC. Although there was a minimal effect on cell growth, miR-503 was found to inhibit cellular invasion significantly. Algorithm-based studies identified multiple potential target genes and pathways associated with oncogenic mechanisms. The candidate target gene, WNT3A, was confirmed to be downregulated by miR-503 at both the mRNA and protein levels and validated by a reporter assay. Furthermore, miR-503 modulated multiple invasion-associated genes, including matrix metalloproteinases (MMPs), through the Wnt downstream signaling pathway. Overall, this study demonstrates that miR-503 suppresses HNC malignancy by inhibiting cell invasion through the Wnt signaling pathway via the WNT3A/MMP molecular axis. The modulation of miR-503 may be a novel therapeutic approach to intervene in cancer invasion.

Correlation Analysis of miR-1246 Expression in Saliva of Patients with Chronic Periodontitis and Periodontal Indexes, Inflammatory Cytokines, and Protease Molecules

Objective. The study aimed to investigate the correlation of miR-1246 in saliva with periodontal indicators, inflammatory cytokines, and protease molecules in patients with chronic periodontitis. Methods. Thirty-five patients with chronic periodontitis were included as the chronic periodontitis group, and 35 healthy individuals were selected as the healthy control group during the same period. The miR-1246 levels, inflammatory cytokine interleukin (IL)-1β, IL-6, IL-17, tumor necrosis factor-α (TNF-α), matrix metalloproteinase (MMP-1), MMP-8, and MMP tissue inhibitor (TIMP-1) in saliva were determined, and periodontal indexes, including the plaque index (PLI), bleeding index (BI), periodontal probing depth (PD), and attachment loss (AL) were examined. Results. The salivary levels of miR-1246, IL-1β, IL-6, IL-17, TNF-α, MMP-1, MMP-8, and TIMP-1 and the periodontal indexes PLI, GI, PD, and AL in the chronic periodontitis group were significantly higher than those in the healthy control ( $P<0.05$ ). Salivary levels of miR-1246 in patients with chronic periodontitis were positively correlated with the levels of IL-1β, IL-6, IL-17, TNF-α, MMP-1, MMP-8, TIMP-1, PLI, GI, PD, and AL ( $P<0.05$ ). Conclusion. Abnormally elevated levels of miR-1246 in saliva of patients with chronic periodontitis correlate with levels of periodontal indices, inflammatory cytokines, and protease molecules.

Human and herpesvirus microRNAs in periodontal disease

Periodontitis is a multi-etiologic infection characterized clinically by pathologic loss of the periodontal ligament and alveolar bone. Herpesviruses and specific bacterial species are major periodontal pathogens that cooperate synergistically in producing severe periodontitis. Cellular immunity against herpesviruses and humoral immunity against bacteria are key periodontal host defenses. Genetic, epigenetic, and environmental factors are modifiers of periodontal disease severity. MicroRNAs are a class of noncoding, gene expression-based, posttranscriptional regulatory RNAs of great importance for maintaining tissue homeostasis. Aberrant expression of microRNAs has been associated with several medical diseases. Periodontal tissue cells and herpesviruses elaborate several microRNAs that are of current research interest. This review attempts to conceptualize the role of periodontal microRNAs in the pathogenesis of periodontitis. The diagnostic potential of salivary microRNAs is also addressed. Employment of microRNA technology in periodontics represents an interesting new preventive and therapeutic possibility.

Research hotspots and trends of microRNA in periodontology and dental implantology: a bibliometric analysis

Background

Periodontal disease is a leading cause of tooth loss, and microRNA (miRNA) has been shown to regulate various biological processes. This study aimed to quantitatively analyze the literature related to miRNA in periodontology and dental implantology and summarize the research hotspots and trends in this field.

Methods

Literature records from 1985 to 2020 were obtained from the Web of Science Core Collection database. After manual selection, the data was used for cooperative network analysis, keyword co-occurrence analysis, and reference co-citation analysis and visualized by CiteSpace.

Results

A total of 287 papers were analyzed between 2007 and 2020, and more than 95% of them were published in the past decade. The largest number of publications were from China, followed by the USA and Japan. The direct cooperation among the productive institutions was not close. At present, most of the research belongs to the discipline of dentistry, oral surgery, cell biology, and molecular biology. Literature clusters generated by reference co-citation analysis and keyword co-occurrence network showed that previous studies mainly focused on four hotspots: periodontal ligament stem cells (PDLSCs), the pathological process of periodontitis, osteogenic differentiation/bone regeneration, and the competing endogenous RNA (ceRNA) network.

Conclusions

The therapeutic potential of miRNA in promoting bone formation and how the ceRNA network contributes to miRNA regulation at a deeper level have become the two main research trends of this field.

Evaluating the Use of microRNA Blood Tests for Gastric Cancer Screening in a Stratified Population-Level Screening Program: An Early Model-Based Cost-Effectiveness Analysis

OBJECTIVES

To evaluate cost-effectiveness of a novel screening strategy using a microRNA (miRNA) blood test as a screen, followed by endoscopy for diagnosis confirmation in a 3-yearly population screening program for gastric cancer.

METHODS

A Markov cohort model has been developed in Microsoft Excel 2016 for the population identified to be at intermediate risk (Singaporean men, aged 50-75 years with Chinese ethnicity). The interventions compared were (1) initial screening using miRNA test followed by endoscopy for test-positive individuals and a 3-yearly follow-up screening for test-negative individuals (proposed strategy), and (2) no screening with gastric cancer being diagnosed clinically (current practice). The model was evaluated for 25 years with a healthcare perspective and accounted for test characteristics, compliance, disease progression, cancer recurrence, costs, utilities, and mortality. The outcomes measured included incremental cost-effectiveness ratios, cancer stage at diagnosis, and thresholds for significant variables.

RESULTS

The miRNA-based screening was found to be cost-effective with an incremental cost-effectiveness ratio of $40 971/quality-adjusted life-year. Key drivers included test costs, test accuracy, cancer incidence, and recurrence risk. Threshold analysis highlights the need for high accuracy of miRNA tests (threshold sensitivity: 68%; threshold specificity: 77%). A perfect compliance to screening would double the cancer diagnosis in early stages compared to the current practice. Probabilistic sensitivity analysis reported the miRNA-based screening to be cost-effective in >95% of iterations for a willingness to pay of $70 000/quality-adjusted life-year (approximately equivalent to 1 gross domestic product/capita) CONCLUSIONS: The miRNA-based screening intervention was found to be cost-effective and is expected to contribute immensely in early diagnosis of cancer by improving screening compliance.

Long Term Delta-9-tetrahydrocannabinol Administration Inhibits Proinflammatory Responses in Minor Salivary Glands of Chronically Simian Immunodeficieny Virus Infected Rhesus Macaques

HIV/SIV-associated oral mucosal disease/dysfunction (HAOMD) (gingivitis/periodontitis/salivary adenitis) represents a major comorbidity affecting HIV patients on anti-retroviral therapy. Using a systems biology approach, we investigated molecular changes (mRNA/microRNA) underlying HAOMD and its modulation by phytocannabinoids (delta-9-tetrahydrocannabinol (∆⁹-THC)) in uninfected (n = 5) and SIV-infected rhesus macaques untreated (VEH-untreated/SIV; n = 7) or treated with vehicle (VEH/SIV; n = 3) or ∆⁹-THC (THC/SIV; n = 3). Relative to controls, fewer mRNAs were upregulated in THC/SIV compared to VEH-untreated/SIV macaques. Gene enrichment analysis showed differential enrichment of biological functions involved in anti-viral defense, Type-I interferon, Toll-like receptor, RIG-1 and IL1R signaling in VEH-untreated/SIV macaques. We focused on the anti-ER-stress anterior gradient-2 (AGR2), epithelial barrier protecting and anti-dysbiotic WAP Four-Disulfide Core Domain-2 (WFDC2) and glucocorticoid-induced anti-inflammatory TSC22D3 (TSC22-domain family member-3) that were significantly downregulated in oropharyngeal mucosa (OPM) of VEH-untreated/SIV macaques. All three proteins localized to minor salivary gland acini and secretory ducts and showed enhanced and reduced expression in OPM of THC/SIV and VEH/SIV macaques, respectively. Additionally, inflammation associated miR-21, miR-142-3p and miR-29b showed significantly higher expression in OPM of VEH-untreated/SIV macaques. TSC22D3 was validated as a target of miR-29b. These preliminary translational findings suggest that phytocannabinoids may safely and effectively reduce oral inflammatory responses in HIV/SIV and other (autoimmune) diseases.

Long non‑coding RNAs are novel players in oral inflammatory disorders, potentially premalignant oral epithelial lesions and oral squamous cell carcinoma (Review)

In recent years, a large number of studies have shown that the abnormal expression of long non‑coding (lnc)RNAs can lead to a variety of different diseases, including inflammatory disorders, cardiovascular disease, nervous system diseases, and cancers. Recent research has demonstrated the biological characteristics of lncRNAs and the important functions of lncRNAs in oral inflammation, precancerous lesions and cancers. The present review aims to explore and discuss the potential roles of candidate lncRNAs in oral diseases by summarizing multiple lncRNA profiles in diseased and healthy oral tissues to determine the altered lncRNA signatures. In addition, to highlight the exact regulatory mechanism of lncRNAs in oral inflammatory disorders, potentially premalignant oral epithelial lesions and oral squamous cell carcinoma. The detection of lncRNAs in oral samples has the potential to be used as a diagnostic and an early detection tool for oral diseases. Furthermore, lncRNAs are promising future therapeutic targets in oral diseases, and research in this field may expand in the future.

Lauric Acid Modulates Cancer-Associated microRNA Expression and Inhibits the Growth of the Cancer Cell

BACKGROUND

microRNAs are known to regulate various protein-coding gene expression posttranscriptionally. Fatty acids are cell membrane constituents and are also known to influence the biological activities of the cells like signal transduction, growth and differentiation of the cells, apoptosis induction, and other physiological functions. In our experiments, we used lauric acid to analyse its effects on human cancerous cell lines.

OBJECTIVE

Our objective was to speculate the miRNA expression profile in lauric acid treated and untreated cancerous cell lines and further study the metabolic pathways of the targeted tumour suppressor and oncogenes.

METHODS

The KB cells and HepG2 cells were treated with lauric acid and miRNA was isolated and the expression of tumour suppressor and oncogenic miRNA was measured by quantitative PCR. The untreated cells were used as control. The metabolic pathways of the target tumour suppressor and oncogenes were examined by GeneMANIA software.

RESULTS

Interestingly, the lauric acid treatment suppresses the expression of oncogenic miRNA and significantly upregulated the expression of some tumour suppressor miRNAs. GeneMANIA metabolic pathway revealed that the upregulated tumour suppressor miRNAs regulate several cancer-associated pathways such as DNA damage, signal transduction p53 class mediator, stem cell differentiation, cell growth, cell cycle phase transition, apoptotic signalling pathway, cellular response to stress and radiation, etc. whereas oncogenic miRNAs regulate the cancer-associated pathway like cell cycle phase transition, apoptotic signalling pathway, cell growth, response to oxidative stress, immune response activating cell surface protein signalling pathway, cyclin-dependent protein kinase activity, epidermal growth factor receptor signalling pathways, etc. Conclusion: In our study, we found that lauric acid works as an anticancer agent by altering the expression of miRNAs.

Salivary Biomarkers for Oral Squamous Cell Carcinoma Diagnosis and Follow-Up: Current Status and Perspectives

Oral cancer is the sixth most common cancer type in the world, and 90% of it is represented by oral squamous cell carcinoma (OSCC). Despite progress in preventive and therapeutic strategies, delay in OSCC diagnosis remains one of the major causes of high morbidity and mortality; indeed the majority of OSCC has been lately identified in the advanced clinical stage (i.e., III or IV). Moreover, after primary treatment, recurrences and/or metastases are found in more than half of the patients (80% of cases within the first 2 years) and the 5-year survival rate is still lower than 50%, resulting in a serious issue for public health. Currently, histological investigation represents the “gold standard” of OSCC diagnosis; however, recent studies have evaluated the potential use of non-invasive methods, such as “liquid biopsy,” for the detection of diagnostic and prognostic biomarkers in body fluids of oral cancer patients. Saliva is a biofluid containing factors such as cytokines, DNA and RNA molecules, circulating and tissue-derived cells, and extracellular vesicles (EVs) that may be used as biomarkers; their analysis may give us useful information to do early diagnosis of OSCC and improve the prognosis. Therefore, the aim of this review is reporting the most recent data on saliva biomarker detection in saliva liquid biopsy from oral cancer patients, with particular attention to circulating tumor DNA (ctDNA), EVs, and microRNAs (miRNAs). Our results highlight that saliva liquid biopsy has several promising clinical uses in OSCC management; it is painless, accessible, and low cost and represents a very helpful source of diagnostic and prognostic biomarker detection. Even if standardized protocols for isolation, characterization, and evaluation are needed, recent data suggest that saliva may be successfully included in future clinical diagnostic processes, with a considerable impact on early treatment strategies and a favorable outcome.

Potential of Melatonin as Adjuvant Therapy of Oral Cancer in the Era of Epigenomics

The wide variety of epigenetic controls available is rapidly expanding the knowledge of molecular biology even overflowing it. At the same time, it can illuminate unsuspected ways of understanding the etiology of cancer. New emerging therapeutic horizons, then, promise to overcome the current antitumor strategies need. The translational utility of this complexity is particularly welcome in oral cancer (OC), in which natural history is alarmingly disappointing due to the invasive and mutilating surgery, the high relapsing rate, the poor quality of life and the reduced survival after diagnosis. Melatonin activates protective receptor-dependent and receptor-independent processes that prevent tissue cancerisation and inhibit progressive tumor malignancy and metastasis. Related evidence has shown that melatonin pleiotropy encompasses gene expression regulation through all the three best-characterized epigenetic mechanisms: DNA methylation, chromatin modification, and non-coding RNA. OC has received less attention than other cancers despite prognosis is usually negative and there are no significant therapy improvements recorded in the past decade. However, a large research effort is being carried out to elucidate how melatonin´s machinery can prevent epigenetic insults that lead to cancer. In the light of recent findings, a comprehensive examination of biochemistry through which melatonin may reverse epigenetic aberrations in OC is an extraordinary opportunity to take a step forward in the clinical management of patients.

Herpesviruses and MicroRNAs: New Pathogenesis Factors in Oral Infection and Disease?

The oral cavity incessantly encounters a plethora of microorganisms. Effective and efficient oral innate and adaptive immune responses are incumbent to maintain healthy mucosa. A higher prevalence of Human Herpesviruses (HHV), a family of large enveloped DNA viruses, has been reported in multiple oral inflammatory diseases suggesting their involvement in disease progression. However, the viral components contributing to oral disease remain obscure. MicroRNAs (miRNA) are non-protein coding, single stranded ribonucleic acid (RNA) molecules that post-transcriptionally regulate diverse messenger RNAs. Thus, miRNAs can control large repertoire of biological processes. Changes in miRNA expression are associated with various oral infections and diseases. Cellular miRNAs can act as pro- or anti-viral factors and dysregulation of host miRNA expression occurs during herpesviruses infection. This strongly suggest a critical role of cellular miRNAs in host-herpesvirus interaction. Interestingly, HHV also encode multiple miRNAs (called viral miRNAs) that may play key role in host-pathogen interaction by modulating both host biological pathways and controlling viral life cycle. Recent studies from our laboratory have identified viral miRNAs (v-miRs) in diseased oral tissue biopsies and demonstrate their immunomodulatory roles. This review discusses the association of miRNAs (both host and viral) and herpesviruses in the pathogenesis of oral inflammatory diseases.

Polymorphisms in four microRNAs and risk of oral squamous cell cancer: a meta-analysis

Objectives

Single nucleotide polymorphisms in microRNAs (microRNA-196a2 rs11614913, microRNA-146a rs2910164, microRNA-149 rs2292832 and microRNA-499 rs3746444) have been inconsistently associated with risk for oral squamous cell cancer (OSCC). This meta-analysis aimed to assess the correlation between microRNA polymorphisms and susceptibility to OSCC.

Materials and Methods

Free words were used to search for the relevant studies without language limitations in electronic databases including PubMed, Embase, Web of Science and SCOPUS through June 15, 2017. Odds ratios (ORs) were calculated to investigate the effects of microRNA polymorphisms on oral cancer risk.

Results

Eleven studies were included. Analysis under the recessive model of microRNA-146a (CC vs GG+CG) showed significant differences (ORs = 0.874, P = 0.041). The G allele and the GG genotype of microRNA-499 were associated with OSCC risk (ORs >1, P < 0.05). MicroRNA-196a2 rs11614913 and microRNA-149 polymorphisms appeared to have no relationship with OSCC risk (P > 0.05). In the sensitivity analysis, there was a significant association between the TT genotype of microRNA-196a2 and OSCC risk (TT vs TC + CC, ORs < 1, P < 0.05).

Conclusions

There may be no significant relationship between microRNA-149 polymorphisms and OSCC risk, and the CC genotype of microRNA-146a may have protective effects against oral cancer. However, the G allele and the GG genotype of microRNA-499 may increase OSCC risk.

Assessing miRNAs profile expression as a risk stratification biomarker in oral potentially malignant disorders: A systematic review

OBJECTIVES

This paper aims to systematically review current findings on altered expression of miRNAs in OPMDs and whether they can be used as risk stratification biomarkers.

METHODS

Studies were collated after searching three different electronic databases: PubMed, Embase, Medline. Additional searches were carried out through cross checking the bibliographies of selected articles. After a thorough selection process made by two of the authors, 40 articles met the inclusion criteria and were included in the review. Studies were assessed and analysed in terms of how the candidate miRNA biomarkers were differentially expressed and validated.

RESULTS

The included studies examined the expression of miRNAs from human specimens (blood serum/plasma, saliva, tissue) as diagnostic or prognostic biomarkers in patients with OPMDs, some of which have been utilised as risk stratification biomarkers for malignant transformation and have showed promising findings.

CONCLUSION

The current evidence to support or refute the prognostic utility of miRNAs in predicting cancer progression in OPMDs is equivocal. Further longitudinal prospective studies with solid study design are warranted.

MicroRNA: Dynamic Regulators of Macrophage Polarization and Plasticity

The ability of a healthy immune system to clear the plethora of antigens it encounters incessantly relies on the enormous plasticity displayed by the comprising cell types. Macrophages (MΦs) are crucial member of the mononuclear phagocyte system (MPS) that constantly patrol the peripheral tissues and are actively recruited to the sites of injury and infection. In tissues, infiltrating monocytes replenish MΦ. Under the guidance of the local micro-milieu, MΦ can be activated to acquire specialized functional phenotypes. Similar to T cells, functional polarization of macrophage phenotype viz., inflammatory (M1) and reparative (M2) is proposed. Equipped with diverse toll-like receptors (TLRs), these cells of the innate arm of immunity recognize and phagocytize antigens and secrete cytokines that activate the adaptive arm of the immune system and perform key roles in wound repair. Dysregulation of MΦ plasticity has been associated with various diseases and infection. MicroRNAs (miRNAs) have emerged as critical regulators of transcriptome output. Their importance in maintaining health, and their contribution toward disease, encompasses virtually all aspects of human biology. Our understanding of miRNA-mediated regulation of MΦ plasticity and polarization can be utilized to modulate functional phenotypes to counter their role in the pathogenesis of numerous disease, including cancer, autoimmunity, periodontitis, etc. Here, we provide an overview of current knowledge regarding the role of miRNA in shaping MΦ polarization and plasticity through targeting of various pathways and genes. Identification of miRNA biomarkers of diagnostic/prognostic value and their therapeutic potential by delivery of miRNA mimics or inhibitors to dynamically alter gene expression profiles in vivo is highlighted.