Type 2 diabetes impairs venous, but not arterial smooth muscle cell function: Possible role of differential RhoA activity

Bioinformatics identifies predictors of arteriovenous fistula maturation

BACKGROUND

Arteriovenous fistulae (AVF) are the preferred access for hemodialysis but still have poor rates of maturation and patency limiting their clinical use. The underlying mechanisms of venous remodeling remain poorly understood, and only limited numbers of unbiased approaches have been reported.

METHODS

Biological Gene Ontology (GO) term enrichment analysis and differentially expressed genes (DEG) analysis were performed for three AVF datasets. A microRNA enrichment analysis and L1000CDS2 query were performed to identify factors predicting AVF patency.

RESULTS

The inflammatory and immune responses were activated during both early and late phases of AVF maturation, with upregulation of neutrophil and leukocyte regulation, cytokine production, and cytokine-mediated signaling. In men with failed AVF, negative regulation of myeloid-leukocyte differentiation and regulation of macrophage activation were significantly upregulated. Compared to non-diabetic patients, diabetic patients had significantly reduced immune response-related enrichment such as cell activation in immune response, regulation of immune-effector process, and positive regulation of defense response; in addition, diabetic patients showed no enrichment of the immune response-regulating signaling pathway.

CONCLUSIONS

These data show coordinated, and differential regulation of genes associated with AVF maturation, and different patterns of several pathways are associated with sex differences in AVF failure. Inflammatory and immune responses are activated during AVF maturation and diabetes may impair AVF maturation by altering these responses. These findings suggest several novel molecular targets to improve sex specific AVF maturation.

Gene-diet interaction analysis using novel weighted food scores discovers the adipocytokine signaling pathway associated with the development of type 2 diabetes

Introduction

The influence of dietary patterns measured using Recommended Food Score (RFS) with foods with high amounts of antioxidant nutrients for Type 2 diabetes (T2D) was analyzed. Our analysis aims to find associations between dietary patterns and T2D and conduct a gene-diet interaction analysis related to T2D.

Methods

Data analyzed in the current study were obtained from the Korean Genome and Epidemiology Study Cohort. The dietary patterns of 46 food items were assessed using a validated food frequency questionnaire. To maximize the predictive power of the RFS, we propose two weighted food scores, namely HisCoM-RFS calculated using the novel Hierarchical Structural Component model (HisCoM) and PLSDA-RFS calculated using Partial Least Squares-Discriminant Analysis (PLS-DA) method.

Results

Both RFS (OR: 1.11; 95% CI: 1.03- 1.20; P = 0.009) and PLSDA-RFS (OR: 1.10; 95% CI: 1.02-1.19, P = 0.011) were positively associated with T2D. Mapping of SNPs (P < 0.05) from the interaction analysis between SNPs and the food scores to genes and pathways yielded some 12 genes (CACNA2D3, RELN, DOCK2, SLIT3, CTNNA2, etc.) and pathways associated with T2D. The strongest association was observed with the adipocytokine signalling pathway, highlighting 32 genes (STAT3, MAPK10, MAPK8, IRS1, AKT1-3, ADIPOR2, etc.) most likely associated with T2D. Finally, the group of the subjects in low, intermediate and high using both the food scores and a polygenic risk score found an association between diet quality groups with issues at high genetic risk of T2D.

Conclusion

A dietary pattern of poor amounts of antioxidant nutrients is associated with the risk of T2D, and diet affects pathway mechanisms involved in developing T2D.

Role of MicroRNA-145 in DNA Damage Signalling and Senescence in Vascular Smooth Muscle Cells of Type 2 Diabetic Patients

Increased cardiovascular morbidity and mortality in individuals with type 2 diabetes (T2DM) is a significant clinical problem. Despite advancements in achieving good glycaemic control, this patient population remains susceptible to macrovascular complications. We previously discovered that vascular smooth muscle cells (SMC) cultured from T2DM patients exhibit persistent phenotypic aberrancies distinct from those of individuals without a diagnosis of T2DM. Notably, persistently elevated expression levels of microRNA-145 co-exist with characteristics consistent with aging, DNA damage and senescence. We hypothesised that increased expression of microRNA-145 plays a functional role in DNA damage signalling and subsequent cellular senescence specifically in SMC cultured from the vasculature of T2DM patients. In this study, markers of DNA damage and senescence were unambiguously and permanently elevated in native T2DM versus non-diabetic (ND)-SMC. Exposure of ND cells to the DNA-damaging agent etoposide inflicted a senescent phenotype, increased expression of apical kinases of the DNA damage pathway and elevated expression levels of microRNA-145. Overexpression of microRNA-145 in ND-SMC revealed evidence of functional links between them; notably increased secretion of senescence-associated cytokines and chronic activation of stress-activated intracellular signalling pathways, particularly the mitogen-activated protein kinase, p38α. Exposure to conditioned media from microRNA-145 overexpressing cells resulted in chronic p38α signalling in naïve cells, evidencing a paracrine induction and reinforcement of cell senescence. We conclude that targeting of microRNA-145 may provide a route to novel interventions to eliminate DNA-damaged and senescent cells in the vasculature and to this end further detailed studies are warranted.

Dermal fibroblasts cultured from donors with type 2 diabetes mellitus retain an epigenetic memory associated with poor wound healing responses

The prevalence of Type 2 diabetes mellitus (T2DM) is escalating globally. Patients suffer from multiple complications including the development of chronic wounds that can lead to amputation. These wounds are characterised by an inflammatory environment including elevated tumour necrosis factor alpha (TNF-α). Dermal fibroblasts (DF) are critical for effective wound healing, so we sought to establish whether there were any differences in DF cultured from T2DM donors or those without diabetes (ND-DF). ND- and T2DM-DF when cultured similarly in vitro secreted comparable concentrations of TNF-α. Functionally, pre-treatment with TNF-α reduced the proliferation of ND-DF and transiently altered ND-DF morphology; however, T2DM-DF were resistant to these TNF-α induced changes. In contrast, TNF-α inhibited ND- and T2DM-DF migration and matrix metalloprotease expression to the same degree, although T2DM-DF expressed significantly higher levels of tissue inhibitor of metalloproteases (TIMP)-2. Finally, TNF-α significantly increased the secretion of pro-inflammatory cytokines (including CCL2, CXCL1 and SERPINE1) in ND-DF, whilst this effect in T2DM-DF was blunted, presumably due to the tendency to higher baseline pro-inflammatory cytokine expression observed in this cell type. Collectively, these data demonstrate that T2DM-DF exhibit a selective loss of responsiveness to TNF-α, particularly regarding proliferative and secretory functions. This highlights important phenotypic changes in T2DM-DF that may explain the susceptibility to chronic wounds in these patients.

Probing Single-Cell Mechanical Allostasis Using Ultrasound Tweezers

Introduction

In response to external stress, cells alter their morphology, metabolic activity, and functions to mechanically adapt to the dynamic, local environment through cell allostasis. To explore mechanotransduction in cellular allostasis, we applied an integrated micromechanical system that combines an 'ultrasound tweezers'-based mechanical stressor and a Förster resonance energy transfer (FRET)-based molecular force biosensor, termed "actinin-sstFRET," to monitor in situ single-cell allostasis in response to transient stimulation in real time.

Methods

The ultrasound tweezers utilize 1 Hz, 10-s transient ultrasound pulses to acoustically excite a lipid-encapsulated microbubble, which is bound to the cell membrane, and apply a pico- to nano-Newton range of forces to cells through an RGD-integrin linkage. The actinin-sstFRET molecular sensor, which engages the actin stress fibers in live cells, is used to map real-time actomyosin force dynamics over time. Then, the mechanosensitive behaviors were examined by profiling the dynamics in Ca²⁺ influx, actomyosin cytoskeleton (CSK) activity, and GTPase RhoA signaling to define a single-cell mechanical allostasis.

Results

By subjecting a 1 Hz, 10-s physical stress, single vascular smooth muscle cells (VSMCs) were observed to remodeled themselves in a biphasic mechanical allostatic manner within 30 min that caused them to adjust their contractility and actomyosin activities. The cellular machinery that underscores the vital role of CSK equilibrium in cellular mechanical allostasis, includes Ca²⁺ influx, remodeling of actomyosin CSK and contraction, and GTPase RhoA signaling. Mechanical allostasis was observed to be compromised in VSMCs from patients with type II diabetes mellitus (T2DM), which could potentiate an allostatic maladaptation.

Conclusions

By integrating tools that simultaneously permit localized mechanical perturbation and map actomyosin forces, we revealed distinct cellular mechanical allostasis profiles in our micromechanical system. Our findings of cell mechanical allostasis and maladaptation provide the potential for mechanophenotyping cells to reveal their pathogenic contexts and their biophysical mediators that underlie multi-etiological diseases such as diabetes, hypertension, or aging.

Platelet-endothelial cell interactions modulate smooth muscle cell phenotype in an in vitro model of type 2 diabetes mellitus

Platelet (PLT)-endothelial cell (EC) interaction appears to contribute to phenotypic transition of vascular smooth muscle cells (VSMCs), which play an important role in the physiological and pathological process of vascular complications in type 2 diabetes mellitus (DM2). However, the precise mechanisms by which interactions between PLTs and ECs affect VSMC phenotype have largely remained unclear. We determined the effect of diabetic PLT-EC interaction to influence VSMC migration, proliferation, and phenotypic transformation in triple-cell coculture models using the quantitative real-time PCR, Western blot, fluorescence microscopy, wound scratch assays, CCK-8 assays, and gelatin zymography assays. Our results revealed DM2 PLT-EC interaction to be associated with a significant downregulation of VSMC-specific contractile phenotypic genes and proteins, including SM22α, smooth muscle actin, Smoothelin-B, and smooth muscle-myosin heavy chain. Inversely, VSMC-specific proliferative phenotype gene and protein levels, including cyclin D1 and 2, nonmuscle myosin heavy chain B, and PCNA were in upregulation. Furthermore, the DM2-originated PLT-EC interaction promoted the expression level of transforming growth factor-β1, and the PI3K/Akt and matrix metalloproteinase 9 signaling pathway was activated subsequently. Finally, these reactions contributed to a synthetic phenotype of VSMCs, including the proliferation, migration, and gelatinolytic activities. These findings suggest that PLT-EC interaction modulates the phenotypic transition of VSMCs between a contractile and proliferative/synthetic phenotype under diabetic conditions, conceivably providing important implications regarding the mechanisms controlling the VSMC phenotypic transition and the development of cardiovascular complications.

The Protective Effect of Total Flavones from Rhododendron simsii Planch. on Myocardial Ischemia/Reperfusion Injury and Its Underlying Mechanism

Objectives

Total flavones from Rhododendron simsii Planch. (TFR) are the effective part extracted from the flowers of Rhododendron simsii Planch. and have obvious protective effects against cerebral ischemic or myocardial injuries in rabbits and rats. However, their mechanism of cardioprotection is still unrevealed. Therefore, the present study was designed to investigate the effect of TFR on myocardial I/R injury and the underlying mechanism.

Methods

TFR groups were treated by gavage once a day for 3 days at a dose of 20, 40, and 80 mg/kg, respectively, and then the model of myocardial I/R injury was established. Myocardial infarction, ST-segment elevation, and the expression of UTR, ROCK1, ROCK2, and p-MLC protein in rat myocardium were determined at 90 min after reperfusion. UTR siRNA in vivo transfection and competition binding assay method were used to study the relationship between the protective effect of TFR and UTR.

Results

The expression of UTR protein markedly decreased in myocardium of UTR siRNA transfection group rats. TFR could significantly reduce the infarct size and inhibit the increase of RhoA activity and ROCK1, ROCK2, and p-MLC protein expressions both in WT and UTR knockdown rats. The reducing rate of TFR in myocardial infarction area, RhoA activity, and ROCK1, ROCK2, and p-MLC protein expressions in UTR knockdown rats decreased markedly compared with that in WT rats. In addition, TFR had no obvious effect on the increase of ΣST in UTR knockdown rats in comparison with that in model group. In particular, TFR could significantly inhibit the combination of [¹²⁵I]-hu-II and UTR, and IC₅₀ was 0.854 mg/l.

Conclusions

The results indicate that the protective effect of TFR on I/R injury may be correlated with its blocking UTR and the subsequent inhibition of RhoA/ROCK signaling pathway.

Progressive Development of Aberrant Smooth Muscle Cell Phenotype in Abdominal Aortic Aneurysm Disease

Abdominal aortic aneurysm (AAA) is a silent, progressive disease with a high mortality and an increasing prevalence with aging. Smooth muscle cell (SMC) dysfunction contributes to gradual dilatation and eventual rupture of the aorta. Here we studied phenotypic characteristics in SMC cultured from end-stage human AAA (≥5 cm) and cells cultured from a porcine carotid artery (PCA) model of early and end-stage aneurysm. Human AAA-SMC presented a secretory phenotype and expressed elevated levels of the differentiation marker miR-145 (2.2-fold, p < 0.001) and the senescence marker SIRT-1 (1.3-fold, p < 0.05), features not recapitulated in aneurysmal PCA-SMC. Human and end-stage porcine aneurysmal cells were frequently multi-nucleated (3.9-fold, p < 0.001, and 1.8-fold, p < 0.01, respectively, vs. control cells) and displayed an aberrant nuclear morphology. Human AAA-SMC exhibited higher levels of the DNA damage marker γH2AX (3.9-fold, p < 0.01, vs. control SMC). These features did not correlate with patients' chronological age and are therefore potential markers for pathological premature vascular aging. Early-stage PCA-SMC (control and aneurysmal) were indistinguishable from one another across all parameters. The principal limitation of human studies is tissue availability only at the end stage of the disease. Refinement of a porcine bioreactor model would facilitate the study of temporal modulation of SMC behaviour during aneurysm development and potentially identify therapeutic targets to limit AAA progression.

Skin-derived precursors from human subjects with Type 2 diabetes yield dysfunctional vascular smooth muscle cells

Objective: Few methods enable molecular and cellular studies of vascular aging or Type 2 diabetes (T2D). Here, we report a new approach to studying human vascular smooth muscle cell (VSMC) pathophysiology by examining VSMCs differentiated from progenitors found in skin. Approach and results: Skin-derived precursors (SKPs) were cultured from biopsies (N=164, ∼1 cm²) taken from the edges of surgical incisions of older adults (N=158; males 72%; mean age 62.7 ± 13 years) undergoing cardiothoracic surgery, and differentiated into VSMCs at high efficiency (>80% yield). The number of SKPs isolated from subjects with T2D was ∼50% lower than those without T2D (cells/g: 0.18 ± 0.03, N=58 versus 0.40 ± 0.05, N=100, P<0.05). Importantly, SKP-derived VSMCs from subjects with T2D had higher Fluo-5F-determined baseline cytosolic Ca²⁺ concentrations (AU: 1,968 ± 160, N=7 versus 1,386 ± 170, N=13, P<0.05), and a trend toward greater Ca²⁺ cycling responses to norepinephrine (NE) (AUC: 177,207 ± 24,669, N=7 versus 101,537 ± 15,881, N=20, P<0.08) despite a reduced frequency of Ca²⁺ cycling (events s^-1 cell^-1: 0.011 ± 0.004, N=8 versus 0.021 ± 0.003, N=19, P<0.05) than those without T2D. SKP-derived VSMCs from subjects with T2D also manifest enhanced sensitivity to phenylephrine (PE) in an impedance-based assay (EC₅₀ nM: 72.3 ± 63.6, N=5 versus 3,684 ± 3,122, N=9, P<0.05), and impaired wound closure in vitro (% closure: 21.9 ± 3.6, N=4 versus 67.0 ± 10.3, N=4, P<0.05). Compared with aortic- and saphenous vein-derived primary VSMCs, SKP-derived VSMCs are functionally distinct, but mirror defects of T2D also exhibited by primary VSMCs.

CONCLUSION

Skin biopsies from older adults yield sufficient SKPs to differentiate VSMCs, which reveal abnormal phenotypes of T2D that survive differentiation and persist even after long-term normoglycemic culture.

Mapping the methylation status of the miR-145 promoter in saphenous vein smooth muscle cells from individuals with type 2 diabetes

Type 2 diabetes mellitus prevalence is growing globally, and the leading cause of mortality in these patients is cardiovascular disease. Epigenetic mechanisms such as microRNAs (miRs) and DNA methylation may contribute to complications of type 2 diabetes mellitus. We discovered an aberrant type 2 diabetes mellitus-smooth muscle cell phenotype driven by persistent up-regulation of miR-145. This study aimed to determine whether elevated expression was due to changes in methylation at the miR-145 promoter. Smooth muscle cells were cultured from saphenous veins of 22 non-diabetic and 22 type 2 diabetes mellitus donors. DNA was extracted, bisulphite treated and pyrosequencing used to interrogate methylation at 11 CpG sites within the miR-145 promoter. Inter-patient variation was high irrespective of type 2 diabetes mellitus. Differential methylation trends were apparent between non-diabetic and type 2 diabetes mellitus-smooth muscle cells at most sites but were not statistically significant. Methylation at CpGs -112 and -106 was consistently lower than all other sites explored in non-diabetic and type 2 diabetes mellitus-smooth muscle cells. Finally, miR-145 expression per se was not correlated with methylation levels observed at any site. The persistent up-regulation of miR-145 observed in type 2 diabetes mellitus-smooth muscle cells is not related to methylation at the miR-145 promoter. Crucially, miR-145 methylation is highly variable between patients, serving as a cautionary note for future studies of this region in primary human cell types.

Therapeutic properties of Scutellaria baicalensis in db/db mice evaluated using Connectivity Map and network pharmacology

We have reported that an extract of Scutellaria baicalensis (ESB) has effects against obesity and hypertriglyceridemia in type 2 diabetic animal model (db/db mouse). In the present study, we tried to explain the pharmacological effects of ESB by integrating gene expression information from db/db mouse liver with that of ESB-treated HepG2 hepatocellular carcinoma cells. Using Connectivity Map (cmap) analysis, we found an inverse relationship in the pharmaceutical profiles based on gene expression between db/db mouse liver and ESB-treated HepG2 cells. This inverse relationship between the two data sets was also observed for pathway activities. Functional network analysis showed that biological functions associated with diabetes and lipid metabolism were commonly enriched in both data sets. We also observed a similarity in distribution of cmap enrichment scores between db/db mouse liver and human diabetic liver, whereas there was an inverse pattern of cmap enrichment scores in human diabetic liver compared with ESB-treated HepG2 cells. This relationship might explain the pharmacological activities of ESB against db/db mouse and possible effectiveness of ESB against human diabetes. We expect that our approach using in vitro cell lines could be applied in predicting the pharmacological effectiveness of herbal drugs in in vivo systems.

Advanced glycation end products impair the functions of saphenous vein but not thoracic artery smooth muscle cells through RAGE/MAPK signalling pathway in diabetes

Saphenous vein (SV) and internal thoracic artery (ITA) are commonly used bypass conduits. However, graft failure occurs in SV rather than in ITA, especially in diabetes (DM). The mechanism for this difference has not been fully understood. Accumulation of advanced glycation end products (AGEs) and activation of AGEs receptor (RAGE) could accelerate smooth muscle cells (SMC) proliferation in DM, we thus asked whether AGEs-RAGE could mediate the differences between SMC from SV (SMCV ) and from ITA (SMCA ). Twenty-five patients with DM and other 25 patients without DM were enclosed in DM and control group, respectively. AGEs (100 μg/ml) were added to cultured SMCA and SMCV obtained at coronary artery bypass graft (CABG) and proliferative rates were determined. Transcript expression, phosphorylation or protein expression levels of MAP kinase family (ERK, p38 and JNK), matrix metalloproteinases (MMP)-2 and MMP-9 were analysed by real-time PCR, Western-blot or immunofluorescence staining, respectively. Compared with paired SMCA , SMCV showed significantly increased proliferation rate, MAP kinase family phosphorylation, and MMP-2/9 expression in both groups, especially in DM group. The responses of SMCV induced by AGEs were significantly larger in DM than in control group, which could be suppressed by inhibition of RAGE and ERK. However, all the cellular events of SMCV were not found in paired SMCA . This study suggests that AGEs-RAGE could induce the proliferation of SMCV but not SMCA via MAP kinase pathway in DM. It is the intrinsic 'inactive' tendency of SMCA that contributes to the different rates of graft disease between SV and ITA after CABG.

Urotensin-ⅡReceptor Antagonist SB-710411 Protects Rat Heart against Ischemia-Reperfusion Injury via RhoA/ROCK Pathway

Aim

SB-710411 is a rat selective urotensin-II (U-II) receptor antagonist, which can block U-II-induced contraction of the aorta and inhibit U-II-induced myocardial fibrosis in rats. However, the effect of SB-710411 on myocardial ischemia-reperfusion (I/R) injury is unclear. The present study was designed to investigate whether SB-710411 has a protective effect on myocardial I/R injury in rats and the possible mechanisms.

Methods and Results

Myocardial I/R injury was induced by occluding the left anterior descending coronary artery in adult male Sprague-Dawley rats. Hemodynamic parameters, electrocardiogram (ECG), infarct size, histological alteration, lactate dehydrogenase (LDH), creatine phosphokinase-MB (CK-MB), cardiac troponin I (cTnI), RhoA, and the protein expressions of U-II receptor (UTR), ROCK₁ and ROCK₂ were evaluated. Cardiac I/R injury significantly up-regulated the expressions of UTR, ROCK₁ and ROCK₂ proteins in rat myocardium. SB-710411 1.0 and 2.0 μg/kg significantly reduced cardiac I/R-induced the infarct size and histological damage in rat myocardium, markedly inhibited the changes of hemodynamic parameters and the increases of ST-segment in ECG, the serum LDH and CK-MB activities and cTnI level in rats subjected to myocardial I/R injury. Furthermore, SB-710411 obviously prevented myocardial I/R-increased RhoA activity and UTR, ROCK₁ and ROCK₂ protein expressions.

Conclusions

Our results indicate that cardiac I/R injury increases myocardial UTR expression, and SB-710411 has a potent protective effect on myocardial I/R injury in rats. The cardioprotection may be associated with the inhibition of UTR-RhoA/ROCK pathway.

Vascular Smooth Muscle as a Target for Novel Therapeutics

Cardiovascular disease is the principal cause of death in patients with type 2 diabetes (T2DM). Exposure of the vasculature to metabolic disturbances leaves a persistent imprint on vascular walls, and specifically on smooth muscle cells (SMC) that favours their dysfunction and potentially underlies macrovascular complications of T2DM. Current diabetes therapies and continued development of newer treatments has led to the ability to achieve more efficient glycaemic control. There is also some evidence to suggest that some of these treatments may exert favourable pleiotropic effects, some of which may be at the level of SMC. However, emerging interest in epigenetic markers as determinants of vascular disease, and a putative link with diabetes, opens the possibility for new avenues to develop robust and specific new therapies. These will likely need to target cell-specific epigenetic changes such as effectors of DNA histone modifications that promote or inhibit gene transcription, and/or microRNAs capable of regulating entire cellular pathways through target gene repression. The growing epidemic of T2DM worldwide, and its attendant cardiovascular mortality, dictates a need for novel therapies and personalised approaches to ameliorate vascular complications in this vulnerable population.

Aberrant phenotype in human endothelial cells of diabetic origin: implications for saphenous vein graft failure?

Type 2 diabetes (T2DM) confers increased risk of endothelial dysfunction, coronary heart disease, and vulnerability to vein graft failure after bypass grafting, despite glycaemic control. This study explored the concept that endothelial cells (EC) cultured from T2DM and nondiabetic (ND) patients are phenotypically and functionally distinct. Cultured human saphenous vein- (SV-) EC were compared between T2DM and ND patients in parallel. Proliferation, migration, and in vitro angiogenesis assays were performed; western blotting was used to quantify phosphorylation of Akt, ERK, and eNOS. The ability of diabetic stimuli (hyperglycaemia, TNF-α, and palmitate) to modulate angiogenic potential of ND-EC was also explored. T2DM-EC displayed reduced migration (~30%) and angiogenesis (~40%) compared with ND-EC and a modest, nonsignificant trend to reduced proliferation. Significant inhibition of Akt and eNOS, but not ERK phosphorylation, was observed in T2DM cells. Hyperglycaemia did not modify ND-EC function, but TNF-α and palmitate significantly reduced angiogenic capacity (by 27% and 43%, resp.), effects mimicked by Akt inhibition. Aberrancies of EC function may help to explain the increased risk of SV graft failure in T2DM patients. This study highlights the importance of other potentially contributing factors in addition to hyperglycaemia that may inflict injury and long-term dysfunction to the homeostatic capacity of the endothelium.

Elevated expression levels of miR-143/5 in saphenous vein smooth muscle cells from patients with Type 2 diabetes drive persistent changes in phenotype and function

Type 2 diabetes (T2DM) promotes premature atherosclerosis and inferior prognosis after arterial reconstruction. Vascular smooth muscle cells (SMC) respond to patho/physiological stimuli, switching between quiescent contractile and activated synthetic phenotypes under the control of microRNAs (miRs) that regulate multiple genes critical to SMC plasticity. The importance of miRs to SMC function specifically in T2DM is unknown. This study was performed to evaluate phenotype and function in SMC cultured from non-diabetic and T2DM patients, to explore any aberrancies and investigate underlying mechanisms. Saphenous vein SMC cultured from T2DM patients (T2DM-SMC) exhibited increased spread cell area, disorganised cytoskeleton and impaired proliferation relative to cells from non-diabetic patients (ND-SMC), accompanied by a persistent, selective up-regulation of miR-143 and miR-145. Transfection of premiR-143/145 into ND-SMC induced morphological and functional characteristics similar to native T2DM-SMC; modulating miR-143/145 targets Kruppel-like factor 4, alpha smooth muscle actin and myosin VI. Conversely, transfection of antimiR-143/145 into T2DM-SMC conferred characteristics of the ND phenotype. Exposure of ND-SMC to transforming growth factor beta (TGFβ) induced a diabetes-like phenotype; elevated miR-143/145, increased cell area and reduced proliferation. Furthermore, these effects were dependent on miR-143/145. In conclusion, aberrant expression of miR-143/145 induces a distinct saphenous vein SMC phenotype that may contribute to vascular complications in patients with T2DM, and is potentially amenable to therapeutic manipulation.