Diverse roles of microRNA-145 in regulating smooth muscle (dys)function in health and disease

YesMicroRNAs are short, non-coding RNAs that target messenger RNAs for degradation. miR-145 is a vascular-enriched microRNA that is important for smooth muscle cell (SMC) differentiation. Under healthy circumstances, SMC exist in a contractile, differentiated phenotype promoted by miR-145. In cases of disease or injury, SMC can undergo reversible dedifferentiation into a synthetic phenotype, accompanied by inhibition of miR-145 expression. Vascular disorders such as atherosclerosis and neointimal hyperplasia are characterised by aberrant phenotypic switching in SMC. This review will summarise the physiological roles of miR-145 in vascular SMC, including the molecular regulation of differentiation, proliferation and migration. Furthermore, it will discuss the different ways in which miR-145 can be dysregulated and the downstream impact this has on the progression of vascular pathologies. Finally, it will discuss whether miR-145 may be suitable for use as a biomarker of vascular disease

Phenotypic differences between microvascular and macrovascular smooth muscle cells and their contribution to coronary microvascular dysfunction

YesCoronary microvascular dysfunction (CMD) is an under-diagnosed condition characterized by functional alteration of the small coronary arterioles and the cardiac capillary bed. The vessels do not dilate appropriately in response to changes in cardiac oxygen demand, leading to chest pain and symptoms of angina. These blood vessels contain two major cell types: the endothelial cells, which line the blood vessels and detect changes in oxygen demand, and smooth muscle cells (SMC) which respond to these changes by contracting or relaxing to provide an optimal blood supply to the cardiac tissue. Many CMD studies have focused on the endothelial cells as these cells secrete vasorelaxants and vasoconstrictors. However, comparably fewer studies have examined SMC despite their functional role in contracting and relaxing. A variety of health conditions and lifestyle choices, such as diabetes, hypertension and cigarette smoking, can promote the development of both CMD and macrovascular coronary artery disease; a condition where SMC have been studied extensively. This review article will consider the influence of CMD on SMC phenotype. It will discuss the structural, cellular and molecular changes in CMD, and will summarise how co-morbidities can have differing effects on micro- and macro-vascular SMC phenotype and function, which complicates the development of new therapeutic avenues for CMD

Therapeutic Targeting of the Proinflammatory IL-6-JAK/STAT Signalling Pathways Responsible for Vascular Restenosis in Type 2 Diabetes Mellitus.

YesType 2 diabetes mellitus (T2DM) is increasing worldwide, and it is associated with increased risk of coronary artery disease (CAD). For T2DM patients, the main surgical intervention for CAD is autologous saphenous vein grafting. However, T2DM patients have increased risk of saphenous vein graft failure (SVGF). While the mechanisms underlying increased risk of vascular disease in T2DM are not fully understood, hyperglycaemia, insulin resistance, and hyperinsulinaemia have been shown to contribute to microvascular damage, whereas clinical trials have reported limited effects of intensive glycaemic control in the management of macrovascular complications. This suggests that factors other than glucose exposure may be responsible for the macrovascular complications observed in T2DM. SVGF is characterised by neointimal hyperplasia (NIH) arising from endothelial cell (EC) dysfunction and uncontrolled migration and proliferation of vascular smooth muscle cells (SMCs). This is driven in part by proinflammatory cytokines released from the activated ECs and SMCs, particularly interleukin 6 (IL-6). IL-6 stimulation of the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT) pathway is a key mechanism through which EC inflammation, SMC migration, and proliferation are controlled and whose activation might therefore be enhanced in patients with T2DM. In this review, we investigate how proinflammatory cytokines, particularly IL-6, contribute to vascular damage resulting in SVGF and how suppression of proinflammatory cytokine responses via targeting the JAK/STAT pathway could be exploited as a potential therapeutic strategy. These include the targeting of suppressor of cytokine signalling (SOCS3), which appears to play a key role in suppressing unwanted vascular inflammation, SMC migration, and proliferation.FTM is supported by a University of Botswana PhD scholarship

Stromal vascular fraction cells from individuals who have previously undergone radiotherapy retain their pro-wound healing properties

YesBeneficial effects have been observed following the transplant of lipoaspirates containing adipose-derived stem cells into chronic wounds caused by oncologic radiotherapy. It is not yet certain whether adipose-derived stem cells are resistant to radiation exposure. Therefore, the aims of this study were to isolate stromal vascular fraction from human breast tissue exposed to radiotherapy and determine the presence of adipose-derived stem cells. Stromal vascular fraction from irradiated donor tissue was compared to commercially sourced pre-adipocytes. Immunocytochemistry was used to determine the presence of adipose-derived stem cell markers. Conditioned media from stromal vascular fraction isolated from irradiated donors was used as a treatment in a scratch wound assay of dermal fibroblasts also isolated from irradiated donors and compared to pre-adipocyte conditioned media and serum free control. This is the first report of human stromal vascular fraction being cultured from previously irradiated breast tissue. Stromal vascular fraction conditioned media from irradiated donors had a similar effect in increasing the migration of dermal fibroblasts from irradiated skin to pre-adipocyte conditioned media from healthy donors. Therefore, the ability of adipose-derived stem cells in the stromal vascular fraction to stimulate dermal fibroblasts in wound healing appears to be preserved following radiotherapy. This study demonstrates that stromal vascular fraction from irradiated patients is viable, functional and may have potential for regenerative medicine techniques following radiotherapy.This research was funded by a Bradford City FC Supporters Fellowship for L.V.T. administered through the Plastic Surgery and Burns Research Unit, University of Bradford

A learning development-faculty collaborative exploration of postgraduate research student mental health in a UK university

YesMental ill-health is an escalating problem in higher education. Not only does this impact students’ ability to learn, it can lead to poor completion, with learners opting to withdraw from studies, even if attainment has been satisfactory. The aim of this study was to gain insight about perceptions of poor mental health from postgraduate research students in a diverse UK university and canvas opinion regarding how the University could improve this. A short, pragmatic survey with basic quantitative and qualitative responses was distributed. This was analysed by a team comprising the learning developer responsible for postgraduate researcher learning development, academics and a doctoral student. The study found that poor mental health was evident, with over three quarters of respondents reporting some experience of mental ill-health. We identified five areas in need of attention: University Systems, Supervisor Training, Well-being Monitoring, Building Networks, and Finance. Sources of University-based stress were finance, administrative support, and an environment where a perception that poor mental health was an expectation rather than a problem was experienced. Students preferred to access support outside the academic environment. This is the first study of its kind at a diverse, plate-glass UK university, to consider research student mental ill-health, with a staff-student team working with data, and the learning developer spear-heading changes across postgraduate research. These findings have already influenced university strategy, staff training, and induction practices. The synthesis of the five areas could be used to visualise where further work is needed to improve mental health in these learners

Adipose tissue: a source of stem cells with potential for regenerative therapies for wound healing

YesInterest in adipose tissue is fast becoming a focus of research after many years of being considered as a simple connective tissue. It is becoming increasingly apparent that adipose tissue contains a number of diverse cell types, including adipose-derived stem cells (ASCs) with the potential to differentiate into a number of cell lineages, and thus has significant potential for developing therapies for regenerative medicine. Currently, there is no gold standard treatment for scars and impaired wound healing continues to be a challenge faced by clinicians worldwide. This review describes the current understanding of the origin, different types, anatomical location, and genetics of adipose tissue before discussing the properties of ASCs and their promising applications for tissue engineering, scarring, and wound healing.The authors thank the Plastic Surgery and Burns Research Unit at the University of Bradford, Bradford, UK for financial support for LV

Role of microRNA-145 in DNA damage signalling and senescence in vascular smooth muscle cells of Type 2 diabetic patients

YesIncreased 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, p38a. Exposure to conditioned media from microRNA-145 overexpressing cells resulted in chronic p38a 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

Linking energy sensing to suppression of JAK-STAT signalling: a potential route for repurposing AMPK activators?

YesExaggerated Janus kinase-signal transducer and activator of transcription (JAKSTAT) signalling is key to the pathogenesis of pro-inflammatory disorders, such as rheumatoid arthritis and cardiovascular diseases. Mutational activation of JAKs is also responsible for several haematological malignancies, including myeloproliferative neoplasms and acute lymphoblastic leukaemia. Accumulating evidence links adenosine 5′-monophosphate (AMP)–activated protein kinase (AMPK), an energy sensor and regulator of organismal and cellular metabolism, with the suppression of immune and inflammatory processes. Recent studies have shown that activation of AMPK can limit JAK-STAT-dependent signalling pathways via several mechanisms. These novel findings support AMPK activation as a strategy for management of an array of disorders characterised by hyper-activation of the JAKSTAT pathway. This review discusses the pivotal role of JAK-STAT signalling in a range of disorders and how both established clinically used and novel AMPK activators might be used to treat these conditions.British Heart Foundation; Diabetes UK; Chief Scientist Office; NHS Greater Glasgow and Clyde Research Endowment Fund; Chest, Heart and Stroke Scotlan

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

YesThe 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.This study was funded by an Iraqi government studentship to AHAA-R

Defining the miRnome of Saphenous Vein Smooth Muscle Cells from Patients with Type 2 Diabetes Mellitus

Citation: Hussain, A.; Asare-Amankwah, Y.; Qureshi, S.; Thornton, M.J.; Palmer, T.M.; Bolanle, I.O.; Wood, I.C.; Turner, N.A.; Porter, K.E.; Tedder, A.; et al. Defining the miRnome of Saphenous Vein Smooth Muscle Cells from Patients with Type 2 Diabetes Mellitus. Diabetology 2024, 5, 178-189. https://doi. Abstract: Type 2 diabetes mellitus (T2DM) patients suffer premature development of cardiovascular disease and commonly require cardiac revascularization using the autologous saphenous vein (SV). Smooth muscle cells (SMCs) are the principal cell type within the vascular wall and are dysfunctional in T2DM SV-SMCs, yet the mechanisms underpinning this are incompletely understood. The purpose of this study was to interrogate differential microRNA (miRNA) expression in SV-SMCs to enhance our understanding of T2DM SV-SMC phenotypic change. miRNA expression in primary human SV-SMCs from T2DM and non-diabetic (ND) donors was determined using an array (n = 6 each of ND and T2DM SV-SMCs). Differentially expressed miRNAs were ranked, and functional annotation of the 30 most differentially expressed miRNAs using DAVID and KEGG analysis revealed pathways related to SMC phenotype, including proliferation, migration, cytokine production and cell signaling. After selecting miRNAs known to be involved in SMC phenotypic regulation, miR-17, miR-29b-2, miR-31, miR-130b and miR-491 were further validated using qRT-PCR (n = 5 each of ND and T2DM SV-SMC), with miR-29b-2 subsequently being removed from further investigation. Potential mRNA targets were identified using mirDIP. Predicted target analysis highlighted likely dysregulation in transcription, epigenetic regulation, cell survival, intracellular signaling and cytoskeletal regulation, all of which are known to be dysfunctional in T2DM SV-SMCs. In conclusion, this paper identified four miRNAs that are dysregulated in T2DM SV-SMCs and are implicated in functional changes in the behavior of these cells. This provides a step forward in our understanding of the molecular and epigenetic regulation of vascular dysfunction in T2DM