The Suppression of miR-199a-3p by Promoter Methylation Contributes to Papillary Thyroid Carcinoma Aggressiveness by Targeting RAP2a and DNMT3a

Estrogen-mediated DNMT1 and DNMT3A recruitment by EZH2 silences miR-570-3p that contributes to papillary thyroid malignancy through DPP4

BACKGROUND

Papillary thyroid carcinoma (PTC) is a common endocrine malignancy. Studies have indicated that estrogen can regulate the expression of miRNAs in numerous malignancies. MiR-570-3p has been shown to have a regulatory function in various cancers. However, studies of the regulatory function of miR-570-3p and a direct link between estrogen (especially estradiol E2) and miR-570-3p in PTC have not been done.

METHODS

Expression of miR-570-3p and its downstream target DPP4 in PTC tissues and cells was predicted using bioinformatics and validated by qRT-PCR and western blot assays. We then performed a series of gain-and-loss experiments to assess the functional significance of miR-570-3p/DPP4 axis in PTC progression in vitro and in vivo. Additionally, the methylation of the miR-570-3p promoter region was examined via bioinformatics analysis and MSP. Finally, the effects of E2 on PTC progression and the correlation between DNMT1/DNMT3A and EZH2 were predicted by bioinformatic tools and proved by luciferase reporter, ChIP, and co-IP assays.

RESULTS

In PTC tumor tissues and cell lines, there was a lower expression level and a higher methylation level of miR-570-3p compared to normal tissues and cell lines. DPP4 was identified as the downstream target of miR-570-3p. Overexpression of miR-570-3p reduced the proliferative, migratory, and invasive capabilities, and promoted apoptosis, while overexpression of DPP4 reversed these effects in PTC cells. It was also discovered that DNMT1 and DNMT3A increased the CpG methylation level of the miR-570-3p promoter in an EZH2-dependent manner, which led to decreased expression of miR-570-3p. Furthermore, we observed that estrogen (E2) enhanced the methylation of miR-570-3p and suppressed its expression levels, resulting in augmented tumor growth in vivo in PTC.

CONCLUSION

Estrogen regulates the EZH2/DNMTs/miR-570-3p/DPP4 signaling pathway to promote PTC progression.

M2 Macrophage-Derived Exosomes Regulate miR-199a-3p Promoter Methylation Through the LINC00470-Mediated myc/DNMT3a Axis to Promote Breast Cancer Development

Breast cancer (BC) is the most common invasive cancer in women. M2 macrophage exosomes promote cancer development and play multiple roles in the tumor microenvironment, but the mechanism of action by which M2 macrophage exosomes promote BC remains unclear. Therefore, the purpose of this study was to investigate the mechanism by which M2 macrophage-derived exosomes promote the development of breast cancer. We collected BC tissues and determined the expression of LINC00470, followed by the establishment of M2 macrophages in culture and the isolation and identification of M2 macrophage exosomes. Next, we investigated the effects of M2 macrophage exosomes on BC cell proliferation, invasion, miR-199a-3p promoter methylation, and the expression of LINC00470, myc, DNMT3A, and miR-199a-3p. Finally, LINC00470 expression was inhibited in M2 macrophage exosomes, while miR-199a-3p expression was inhibited in BC cells, and changes in BC cell proliferation, invasion, miR-199a-3p promoter methylation, and the expression of LINC00470, myc, DNMT3A, and miR-199a-3p were analyzed. We demonstrated that LINC00470 was highly expressed in BC tissues, M2-type macrophages were successfully induced in vitro, and Dil-labeled M2 macrophage exosomes could successfully enter MDA-MB-231 and MCF-7 cells. Coculture of M2 macrophage exosomes with MDA-MB-231 and MCF-7 cells significantly enhanced the proliferation and invasion of MDA-MB-231 and MCF-7 cells, upregulated the expression of LINC00470, myc, and DNMT3A and downregulated the expression of miR-199a-3p. Moreover, the inhibition of LINC00470 expression in M2 macrophage exosomes significantly downregulated the expression of LINC00470, myc, and DNMT3A in MDA-MB-231 and MCF-7 cells, upregulated the expression of miR-199a-3p, and hypomethylated the promoter of the miR-199a-3p locus. Moreover, inhibition of LINC00470 expression in M2 macrophage-derived exosomes significantly attenuated the proliferation and invasive ability of MDA-MB-231 and MCF-7 cells, while miR-199a-3p inhibitor transfection reversed this effect. Collectively, these findings indicated that M2-type macrophage-derived exosomes promote BC proliferation and migration by regulating miR-199a-3p promoter methylation through the LINC00470-mediated myc/DNMT3a axis.

From molecular pathogenesis to therapy: Unraveling non-coding RNAs/DNMT3A axis in human cancers

Cancer is a comprehensive classification encompassing more than 100 forms of malignancies that manifest in diverse tissues within the human body. Recent studies have provided evidence that aberrant epigenetic modifications are pivotal indicators of cancer. Epigenetics encapsulates DNA methyltransferases as a crucial class of modifiers. DNMTs, including DNMT3A, assume central roles in DNA methylation processes that orchestrate normal biological functions, such as gene transcription, predominantly in mammals. Typically, deviations in DNMT3A function engender distortions in factors that drive tumor growth and progression, thereby exacerbating the malignant phenotype of tumors. Consequently, such abnormalities pose significant challenges in cancer therapy because they impede treatment efficacy. Non-coding RNAs (ncRNAs) represent a group of RNA molecules that cannot encode functional proteins. Recent investigation attests to the crucial significance of regulatory ncRNAs in epigenetic regulation. Notably, recent reports have illuminated the complex interplay between ncRNA expression and epigenetic regulatory machinery, including DNMT3A, particularly in cancer. Recent findings have demonstrated that miRNAs, namely miR-770-5p, miR-101, and miR-145 exhibit the capability to target DNMT3A directly, and their aberration is implicated in diverse cellular abnormalities that predispose to cancer development. This review aims to articulate the interplay between DNMT3A and the ncRNAs, focusing on its impact on the development and progression of cancer, cancer therapy resistance, cancer stem cells, and prognosis. Importantly, the emergence of such reports that suggest a connection between DNMT3A and ncRNAs in several cancers indicates that this connecting axis offers a valuable target with significant therapeutic potential that might be exploited for cancer management.

Hyperbranched polyamidoamine-RGD peptide/si-circICA1 in the treatment of invasive thyroid cancer through targeting of the miR-486-3p/SERPINA1 axis

Aim: This study aimed to identify molecular markers associated with papillary thyroid cancer (PTC) and investigate the therapeutic potential of targeted nanoscale drugs. Materials & methods: We analyzed the effects of circICA1 and miR-486-3p on B-CPAP cells' proliferation, apoptosis, migration and invasion. The regulation of the miR-486-3p/SERPINA1 axis was explored using quantitative real-time reverse transcription PCR and western blot analyses for metastasis. In vivo, we evaluated the effects of hyperbranched polyamidoamine-RGD peptide/si-circICA1 on PTC growth and metastasis. Results: Enhanced miR-486-3p expression inhibits B-CPAP cells' proliferation and invasion. si-circICA1 delivered via hyperbranched polyamidoamine-RGD peptide nanoparticles shows potential for treating metastasis in PTC. Conclusion: This study identifies key molecular mechanisms underlying PTC invasiveness and suggests a promising therapeutic strategy for PTC using targeted nanoscale drugs.

Transcriptomic analyses of ovarian clear-cell carcinoma with concurrent endometriosis

Introduction

Endometriosis, a benign inflammatory disease whereby endometrial-like tissue grows outside the uterus, is a risk factor for endometriosis-associated ovarian cancers. In particular, ovarian endometriomas, cystic lesions of deeply invasive endometriosis, are considered the precursor lesion for ovarian clear-cell carcinoma (OCCC).

Methods

To explore this transcriptomic landscape, OCCC from women with pathology-proven concurrent endometriosis (n = 4) were compared to benign endometriomas (n = 4) by bulk RNA and small-RNA sequencing.

Results

Analysis of protein-coding genes identified 2449 upregulated and 3131 downregulated protein-coding genes (DESeq2, P< 0.05, log2 fold-change > |1|) in OCCC with concurrent endometriosis compared to endometriomas. Gene set enrichment analysis showed upregulation of pathways involved in cell cycle regulation and DNA replication and downregulation of pathways involved in cytokine receptor signaling and matrisome. Comparison of pathway activation scores between the clinical samples and publicly-available datasets for OCCC cell lines revealed significant molecular similarities between OCCC with concurrent endometriosis and OVTOKO, OVISE, RMG1, OVMANA, TOV21G, IGROV1, and JHOC5 cell lines. Analysis of miRNAs revealed 64 upregulated and 61 downregulated mature miRNA molecules (DESeq2, P< 0.05, log2 fold-change > |1|). MiR-10a-5p represented over 21% of the miRNA molecules in OCCC with endometriosis and was significantly upregulated (NGS: log2fold change = 4.37, P = 2.43e-18; QPCR: 8.1-fold change, P< 0.05). Correlation between miR-10a expression level in OCCC cell lines and IC50 (50% inhibitory concentration) of carboplatin in vitro revealed a positive correlation (R2 = 0.93). MiR-10a overexpression in vitro resulted in a significant decrease in proliferation (n = 6; P< 0.05) compared to transfection with a non-targeting control miRNA. Similarly, the cell-cycle analysis revealed a significant shift in cells from S and G2 to G1 (n = 6; P< 0.0001). Bioinformatic analysis predicted that miR-10a-5p target genes that were downregulated in OCCC with endometriosis were involved in receptor signaling pathways, proliferation, and cell cycle progression. MiR-10a overexpression in vitro was correlated with decreased expression of predicted miR-10a target genes critical for proliferation, cell-cycle regulation, and cell survival including [SERPINE1 (3-fold downregulated; P< 0.05), CDK6 (2.4-fold downregulated; P< 0.05), and RAP2A (2-3-fold downregulated; P< 0.05)].

Discussion

These studies in OCCC suggest that miR-10a-5p is an impactful, potentially oncogenic molecule, which warrants further studies.

Cold exposure protects against medial arterial calcification development via autophagy

Medial arterial calcification (MAC), a systemic vascular disease different from atherosclerosis, is associated with an increased incidence of cardiovascular events. Several studies have demonstrated that ambient temperature is one of the most important factors affecting cardiovascular events. However, there has been limited research on the effect of different ambient temperatures on MAC. In the present study, we showed that cold temperature exposure (CT) in mice slowed down the formation of vitamin D (VD)-induced vascular calcification compared with room temperature exposure (RT). To investigate the mechanism involved, we isolated plasma-derived exosomes from mice subjected to CT or RT for 30 days (CT-Exo or RT-Exo, respectively). Compared with RT-Exo, CT-Exo remarkably alleviated the calcification/senescence formation of vascular smooth muscle cells (VSMCs) and promoted autophagy by activating the phosphorylation of AMP-activated protein kinase (p-AMPK) and inhibiting phosphorylation of mammalian target of rapamycin (p-mTOR). At the same time, CT-Exo promoted autophagy in β-glycerophosphate (β-GP)-induced VSMCs. The number of autophagosomes and the expression of autophagy-related proteins ATG5 and LC3B increased, while the expression of p62 decreased. Based on a microRNA chip microarray assay and real-time polymerase chain reaction, miR-320a-3p was highly enriched in CT-Exo as well as thoracic aortic vessels in CT mice. miR-320a-3p downregulation in CT-Exo using AntagomiR-320a-3p inhibited autophagy and blunted its anti-calcification protective effect on VSMCs. Moreover, we identified that programmed cell death 4 (PDCD4) is a target of miR-320a-3p, and silencing PDCD4 increased autophagy and decreased calcification in VSMCs. Treatment with CT-Exo alleviated the formation of MAC in VD-treated mice, while these effects were partially reversed by GW4869. Furthermore, the anti-arterial calcification protective effects of CT-Exo were largely abolished by AntagomiR-320a-3p in VD-induced mice. In summary, we have highlighted that prolonged cold may be a good way to reduce the incidence of MAC. Specifically, miR-320a-3p from CT-Exo could protect against the initiation and progression of MAC via the AMPK/mTOR autophagy pathway.

MiR-29b level-mediated regulation of Klotho methylation via DNMT3A targeting in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterized by chronic bronchitis and emphysema. Cigarette smoke extract (CSE) is the predominant cause of COPD. This study aimed to investigate the effects of miR-29b and their underlying mechanisms in a COPD cell model. MiR-29b and DNMT3A expression in lung tissue samples (taken at least 5 cm away from the tumor lesion) of NSCLC cases with smoking (n = 30), without smoking (n = 30), and with COPD (with smoking) (n = 30) was researched by qRT-PCR. A medium containing 10 % CSE was employed to induce murine alveolar macrophage MH-S cells to establish COPD cells. 5-Aza-cdr (5-AZA-2'-deoxycytidine) was used to block DNMT3A. The relationship and interaction between miR-29b and DNMT3A were validated through the dual luciferase reporter assay. The expression levels of macrophage M1 polarization marker proteins iNOS and TNF-α, DNMT3A, and Klotho protein were monitored using western blotting. The methylation levels of the miR-29b precursor gene and Klotho promoter were detected by quantitative methylation-specific PCR (MS-qPCR). The levels of IL-1β, IL-6, and TNF-α in cell culture medium were detected via ELISA. It was found that the expression of miR-29b was downregulated, as a result of increased DNA methylation, and that of DNMT3A was upregulated in the lung tissues of NSCLC cases with COPD (with smoking). DNMT3A expression was negatively correlated with miR-29b expression in the lung tissues of NSCLC cases with COPD (with smoking). In addition, miR-29b expression was distinctly downregulated in CSE-induced MH-S cells and inhibited CSE-induced M1 polarization and inflammation. Importantly, DNMT3A was identified as a direct target gene of miR-29b. MiR-29b is negatively regulated by DNMT3A-mediated DNA methylation. Moreover, Klotho expression was downregulated and the Klotho promoter methylation level was increased in lung tissues of NSCLC cases with COPD (with smoking). The negative feedback between miR-29b and DNMT3A modulates CSE-induced M1 polarization and inflammation in macrophages as well as Klotho promoter methylation in CSE-mediated MH-S. Collectively, these findings indicate that the miR-29b level in COPD controls Klotho methylation via DNMT3, which maybe a promising target for the treatment of COPD.

Evaluation of altered miRNA expression pattern to predict COVID-19 severity

Outbreak of COVID-19 pandemic in December 2019 affected millions of people globally. After substantial research, several biomarkers for COVID-19 have been validated however no specific and reliable biomarker for the prognosis of patients with COVID-19 infection exists. Present study was designed to identify specific biomarkers to predict COVID-19 severity and tool for formulating treatment. A small cohort of subjects (n = 43) were enrolled and categorized in four study groups; Dead (n = 16), Severe (n = 10) and Moderate (n = 7) patients and healthy controls (n = 10). Small RNA sequencing was done on Illumina platform after isolation of microRNA from peripheral blood. Differential expression (DE) of miRNA (patients groups compared to control) revealed 118 down-regulated and 103 up-regulated known miRNAs with fold change (FC) expression ≥2 folds and p ≤ 0.05. DE miRNAs were then subjected to functional enrichment and network analysis. Bioinformatic analysis resulted in 31 miRNAs (24 Down-regulated; 7 up-regulated) significantly associated with COVID-19 having AUC>0.8 obtained from ROC curve. Seventeen out of 31 DE miRNAs have been linked to COVID-19 in previous studies. Three miRNAs, hsa-miR-147b-5p and hsa-miR-107 (down-regulated) and hsa-miR-1299 (up-regulated) showed significant unique DE in Dead patients. Another set of 4 miRNAs, hsa-miR-224-5p (down-regulated) and hsa-miR-4659b-3p, hsa-miR-495-3p and hsa-miR-335-3p were differentially up-regulated uniquely in Severe patients. Members of three miRNA families, hsa-miR-20, hsa-miR-32 and hsa-miR-548 were significantly down-regulated in all patients group in comparison to healthy controls. Thus a distinct miRNA expression profile was observed in Dead, Severe and Moderate COVID-19 patients. Present study suggests a panel of miRNAs which identified in COVID-19 patients and could be utilized as potential diagnostic biomarkers for predicting COVID-19 severity.

MiR-199a-3p Induces Mesenchymal to Epithelial Transition of Keratinocytes by Targeting RAP2B

Cutaneous squamous cell carcinoma (CSCC) is an epidermal skin cancer that evolves from normal epidermis along several pre-malignant stages. Previously we found specific miRNAs alterations in each step along these stages. miR-199a-3p expression decreases at the transition to later stages. A crucial step for epithelial carcinoma cells to acquire invasive capacity is the disruption of cell-cell contacts and the gain of mesenchymal motile phenotype, a process known as epithelial-to-mesenchymal transition (EMT). This study aims to study the role of decreased expression of miR-199a-3p in keratinocytes' EMT towards carcinogenesis. First, we measured miR-199a-3p in different stages of epidermal carcinogenesis. Then, we applied Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP) assay to search for possible biochemical targets of miR-199a-3p and verified that Ras-associated protein B2 (RAP2B) is a bona-fide target of miR-199a-3p. Next, we analyzed RAP2B expression, in CSCC biopsies. Last, we evaluated possible mechanisms leading to decreased miR-199a-3p expression. miR-199a-3p induces a mesenchymal to epithelial transition (MET) in CSSC cells. Many of the under-expressed genes in CSCC overexpressing miR-199a-3p, are possible targets of miR-199a-3p and play roles in EMT. RAP2B is a biochemical target of miR-199a-3p. Overexpression of miR-199a-3p in CSCC results in decreased phosphorylated focal adhesion kinase (FAK). In addition, inhibiting FAK phosphorylation inhibits EMT marker genes' expression. In addition, we proved that DNA methylation is part of the mechanism by which miR-199a-3p expression is inhibited. However, it is not by the methylation of miR-199a putative promoter. These findings suggest that miR-199a-3p inhibits the EMT process by targeting RAP2B. Inhibitors of RAP2B or FAK may be effective therapeutic agents for CSCC.

CircPTPRM accelerates malignancy of papillary thyroid cancer via miR-885-5p/DNMT3A axis

Background

Circular RNAs (circRNAs) are implicated in carcinogenesis, including papillary thyroid cancer (PTC). Despite of previous reports regarding the high expression of circPTPRM in PTC, the role and regulatory mechanism remain to be investigated.

Methods

CircPTPRM and miR‐885‐5p expression were examined, and the effects on cell proliferation, migration, and invasion were also measured. Immunoblotting was performed to evaluate DNA methyltransferase 3A (DNMT3A) and the epithelial‐mesenchymal transition (EMT)‐associated proteins.

Results

CircPTPRM was overexpressed in PTC tissues and cell lines, which predicted poor prognosis. CircPTPRM inhibition significantly alleviated the proliferation, migration, and invasion abilities. It was subsequently confirmed that circPTPRM competed with miR‐885‐5p for DNMT3A binding. CircPTPRM promoted PTC progression via miR‐885‐5p/DNMT3A signal axis.

Conclusion

Our data elucidated that circPTPRM may play an oncogenic role in PTC through circPTPRM/miR‐885‐5p/DNMT3A axis

miR-199a: A Tumor Suppressor with Noncoding RNA Network and Therapeutic Candidate in Lung Cancer

Lung cancer is the leading cause of cancer death worldwide. miR-199a, which has two mature molecules: miR-199a-3p and miR-199a-5p, plays an important biological role in the genesis and development of tumors. We collected recent research results on lung cancer and miR-199a from Google Scholar and PubMed databases. The biological functions of miR-199a in lung cancer are reviewed in detail, and its potential roles in lung cancer diagnosis and treatment are discussed. With miR-199a as the core point and a divergence outward, the interplay between miR-199a and other ncRNAs is reviewed, and a regulatory network covering various cancers is depicted, which can help us to better understand the mechanism of cancer occurrence and provide a means for developing novel therapeutic strategies. In addition, the current methods of diagnosis and treatment of lung cancer are reviewed. Finally, a conclusion was drawn: miR-199a inhibits the development of lung cancer, especially by inhibiting the proliferation, infiltration, and migration of lung cancer cells, inhibiting tumor angiogenesis, increasing the apoptosis of lung cancer cells, and affecting the drug resistance of lung cancer cells. This review aims to provide new insights into lung cancer therapy and prevention.

H19 Promotes Osteoblastic Transition by Acting as ceRNA of miR-140-5p in Vascular Smooth Muscle Cells

Arterial medial calcification is a common disease in patients with type 2 diabetes, end-stage renal disease and hypertension, resulting in high incidence and mortality of cardiovascular event. H19 has been demonstrated to be involved in cardiovascular diseases like aortic valve diseases. However, role of H19 in arterial medial calcification remains largely unknown. We identified that H19 was upregulated in ß-glycerophosphate (β-GP) induced vascular smooth muscle cells (VSMCs), a cellular calcification model in vitro. Overexpression of H19 potentiated while knockdown of H19 inhibited osteogenic differentiation of VSMCs, as demonstrated by changes of osteogenic genes Runx2 and ALP as well as ALP activity. Notably, H19 interacted with miR-140-5p directly, as demonstrated by luciferase report system and RIP analysis. Mechanistically, miR-140-5p attenuated osteoblastic differentiation of VSMCs by targeting Satb2 and overexpression of miR-140-5p blocked H19 induced elevation of Satb2 as well as the promotion of osteoblastic differentiation of VSMCs. Interestingly, over-expression of Satb2 induced phosphorylation of ERK1/2 and p38MAPK. In conclusion, H19 promotes VSMC calcification by acting as competing endogenous RNA of miR-140-5p and at least partially by activating Satb2-induced ERK1/2 and p38MAPK signaling.

miR-199a Downregulation as a Driver of the NOX4/HIF-1α/VEGF-A Pathway in Thyroid and Orbital Adipose Tissues from Graves′ Patients

Graves’ disease (GD) is an autoimmune thyroiditis often associated with Graves’ orbitopathy (GO). GD thyroid and GO orbital fat share high oxidative stress (OS) and hypervascularization. We investigated the metabolic pathways leading to OS and angiogenesis, aiming to further decipher the link between local and systemic GD manifestations. Plasma and thyroid samples were obtained from patients operated on for multinodular goiters (controls) or GD. Orbital fats were from GO or control patients. The NADPH-oxidase-4 (NOX4)/HIF-1α/VEGF-A signaling pathway was investigated by Western blotting and immunostaining. miR-199a family expression was evaluated following quantitative real-time PCR and/or in situ hybridization. In GD thyroids and GO orbital fats, NOX4 was upregulated and correlated with HIF-1α stabilization and VEGF-A overexpression. The biotin assay identified NOX4, HIF-1α and VEGF-A as direct targets of miR-199a-5p in cultured thyrocytes. Interestingly, GD thyroids, GD plasmas and GO orbital fats showed a downregulation of miR-199a-3p/-5p. Our results also highlighted an activation of STAT-3 signaling in GD thyroids and GO orbital fats, a transcription factor known to negatively regulate miR-199a expression. We identified NOX4/HIF-1α/VEGF-A as critical actors in GD and GO. STAT-3-dependent regulation of miR-199a is proposed as a common driver leading to these events in GD thyroids and GO orbital fats.

Aberrant expression of PROS1 correlates with human papillary thyroid cancer progression

Background

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer (TC). Considering the important association between cellular immunity and PTC progression, it is worth exploring the biological significance of immune-related signaling in PTC.

Methods

Several bioinformatics tools, such as R software, WEB-based Gene SeT AnaLysis Toolkit (WebGestalt), Database for Annotation, Visualization and Integrated Discovery (DAVID), Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape were used to identify the immune-related hub genes in PTC. Furthermore, in vitro experiments were adopted to identify the proliferation and migration ability of PROS1 knockdown groups and control groups in PTC cells.

Results

The differentially expressed genes (DEGs) of five datasets from Gene Expression Omnibus (GEO) contained 154 upregulated genes and 193 downregulated genes, with Protein S (PROS1) being the only immune-related hub gene. Quantitative real-time polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) have been conducted to prove the high expression of PROS1 in PTC. Moreover, PROS1 expression was significantly correlated with lymph nodes classification. Furthermore, knockdown of PROS1 by shRNAs inhibited the cell proliferation and cell migration in PTC cells.

Conclusions

The findings unveiled the clinical relevance and significance of PROS1 in PTC and provided potential immune-related biomarkers for PTC development and prognosis.

The Multi-Therapeutic Role of MSCs in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common diabetes mellitus (DM) microvascular complications, which always ends with end-stage renal disease (ESRD). Up to now, as the treatment of DN in clinic is still complicated, ESRD has become the main cause of death in diabetic patients. Mesenchymal stem cells (MSCs), with multi-differentiation potential and paracrine function, have attracted considerable attention in cell therapy recently. Increasing studies concerning the mechanisms and therapeutic effect of MSCs in DN emerged. This review summarizes several mechanisms of MSCs, especially MSCs derived exosomes in DN therapy, including hyperglycemia regulation, anti-inflammatory, anti-fibrosis, pro-angiogenesis, and renal function protection. We also emphasize the limitation of MSCs application in the clinic and the enhanced therapeutic role of pre-treated MSCs in the DN therapy. This review provides balanced and impartial views for MSC therapy as a promising strategy in diabetic kidney disease amelioration.