Micro-RNA 92a as a Therapeutic Target for Cardiac Microvascular Dysfunction in Diabetes

Microvascular dysfunction is a pathological hallmark of diabetes, and is central to the ethology of diabetes-associated cardiac events. Herein, previous studies have highlighted the role of the vasoactive micro-RNA 92a (miR-92a) in small, as well as large, animal models. In this study, we explore the effects of miR-92a on mouse and human cardiac microvascular endothelial cells (MCMEC, HCMEC), and its underlying molecular mechanisms. Diabetic HCMEC displayed impaired angiogenesis and a pronounced inflammatory phenotype. Quantitative PCR (qPCR) showed an upregulation of miR-92a in primary diabetic HCMEC. Downregulation of miR-92a by antagomir transfection in diabetic HCMEC rescued angiogenesis and ameliorated diabetic endothelial bed inflammation. Furthermore, additional analysis of potential in silico-identified miR-92a targets in diabetic HCMEC revealed the miR-92a dependent downregulation of an essential metalloprotease, ADAM10. Accordingly, downregulation of ADAM10 impaired angiogenesis and wound healing in MCMEC. In myocardial tissue slices from diabetic pigs, ADAM10 dysregulation in micro- and macro-vasculature could be shown. Altogether, our data demonstrate the role of miR-92a in cardiac microvascular dysfunction and inflammation in diabetes. Moreover, we describe for the first time the metalloprotease ADAM10 as a novel miR-92a target, mediating its anti-angiogenic effect.

Steroid-Induced Osteonecrosis of the Femoral Head: Novel Insight Into the Roles of Bone Endothelial Cells in Pathogenesis and Treatment

Steroid-induced osteonecrosis of the femoral head (SONFH) is a disease characterized by the collapse of the femoral head. SONFH occurs due to the overuse of glucocorticoids (GCs) in patients with immune-related diseases. Among various pathogenesis proposed, the mechanism related to impaired blood vessels is gradually becoming the most convincing hypothesis. Bone endothelial cells including bone microvascular endothelial cells (BMECs) and endothelial progenitor cells (EPCs) play a crucial role in the maintenance of vascular homeostasis. Therefore, bone endothelial cells are key regulators in the occurrence and progression of SONFH. Impaired angiogenesis, abnormal apoptosis, thrombosis and fat embolism caused by the dysfunctions of bone endothelial cells are considered to be the pathogenesis of SONFH. In addition, even with high disability rates, SONFH lacks effective therapeutic approach. Icariin (ICA, a flavonoid extracted from Epimedii Herba), pravastatin, and VO-OHpic (a potent inhibitor of PTEN) are candidate reagents to prevent and treat SONFH through improving above pathological processes. However, these reagents are still in the preclinical stage and will not be widely used temporarily. In this case, bone tissue engineering represented by co-transplantation of bone endothelial cells and bone marrow mesenchymal stem cells (BMSCs) may be another feasible therapeutic strategy.

Reprogrammed transsulfuration promotes basal-like breast tumor progression via realigning cellular cysteine persulfidation

Basal-like breast cancer (BLBC) is the most aggressive subtype of breast tumors with poor prognosis and limited molecular-targeted therapy options. We show that BLBC cells have a high Cys demand and reprogrammed Cys metabolism. Patient-derived BLBC tumors from four different cohorts exhibited elevated expression of the transsulfuration enzyme cystathione β-synthetase (CBS). CBS silencing (shCBS) made BLBC cells less invasive, proliferate slower, more vulnerable to oxidative stress and cystine (CySSCy) deprivation, prone to ferroptosis, and less responsive to HIF1-α activation under hypoxia. shCBS xenograft tumors grew slower than controls and exhibited impaired angiogenesis and larger necrotic areas. Sulfur metabolite profiling suggested that realigned sulfide/persulfide-inducing functions of CBS are important in BLBC tumor progression. Supporting this, the exclusion of serine, a substrate of CBS for producing Cys but not for producing sulfide/persulfide, did not exacerbate CySSCy deprivation–induced ferroptosis in shCBS BLBC cells. Impaired Tyr phosphorylation was detected in shCBS cells and xenografts, likely due to persulfidation-inhibited phosphatase functions. Overexpression of cystathione γ-lyase (CSE), which can also contribute to cellular sulfide/persulfide production, compensated for the loss of CBS activities, and treatment of shCBS xenografts with a CSE inhibitor further blocked tumor growth. Glutathione and protein-Cys levels were not diminished in shCBS cells or xenografts, but levels of Cys persulfidation and the persulfide-catabolizing enzyme ETHE1 were suppressed. Finally, expression of enzymes of the oxidizing Cys catabolism pathway was diminished, but expression of the persulfide-producing CARS2 was elevated in human BLBC tumors. Hence, the persulfide-producing pathways are major targetable determinants of BLBC pathology that could be therapeutically exploited.

Melatonin ameliorates aging-related impaired angiogenesis in gastric endothelial cells via local actions on mitochondria & VEGF-survivin signaling

BACKGROUND & AIMS: Tissue injury healing is impaired in aging, and this impairment is caused in part by reduced angiogenesis. Melatonin, a neuroendocrine hormone that regulates sleep and circadian rhythm is also produced in the gastrointestinal tract. The expression of melatonin receptors - MT1 and MT2 in gastric endothelial cells, and their roles in aging-related impairment of gastric angiogenesis, have not been examined. We hypothesized that MT1 and MT2 expression is reduced in gastric endothelial cells of aging rats and that melatonin treatment can upregulate their expression and improve angiogenesis. METHODS: We examined the expression of MT1 and MT2 in gastric endothelial cells (GECs) isolated from young and aging rats. We also examined the effects of melatonin treatment on angiogenesis, GEC mitochondrial function, expression of vascular endothelial growth factor (VEGF), its signaling receptor (VEGFR-2), and the inhibitor of apoptosis protein, survivin. RESULTS: Young and aging GECs expressed MT1 (in the cytoplasm and mitochondria) and MT2 (in nucleus and mitochondria). In aging GECs, MT1 and MT2 levels, in vitro angiogenesis, and mitochondrial membrane potential were significantly reduced (by 1.5-fold, 1.9-fold, 3.1-fold, 1.63-fold, respectively) vs. young GECs. Melatonin treatment of aging GECs significantly increased MT1 and MT2 expression vs. controls, induced nuclear translocation of MT1, and significantly ameliorated the aging-related impairment of angiogenesis and mitochondrial function. CONCLUSIONS: Aging GECs have significantly reduced MT1 and MT2 expression, angiogenesis, and mitochondrial membrane potential vs. young GECs. Treatment of aging GECs with melatonin increases expression of VEGF receptor and survivin and ameliorates aging-related impaired angiogenesis and mitochondrial function.

Autophagy Activation by Hypoxia Regulates Angiogenesis and Apoptosis in Oxidized Low-Density Lipoprotein-Induced Preeclampsia

Objective: Autophagy influences a wide range of physiological and pathological processes in the human body. In this study, we aimed to investigate the role of autophagy in early-onset preeclampsia (EOPE); autophagy activation by hypoxia could rescue impaired angiogenesis and apoptosis in preeclampsia, leading by ox-LDL.Methods: Transmission electron microscopy was applied to identify autolysosomes in trophoblast cells of the placenta apical region. Quantitative real-time polymerase chain reaction, Western blot, flow cytometry, and wound-healing assays were adopted to determine autophagy activity, angiogenesis, and apoptosis in placenta tissues or HTR8/SVneo cells.Results: Autophagy activity was inhibited in the placenta of women who experienced EOPE; autophagy activation by hypoxia enhanced the migration ability, rescued ox-LDL–mediated impaired angiogenesis in HTR8/SVneo cells [vascular endothelial growth factor A (VEGFA) downregulation and FMS-like tyrosine kinase-1 (FLT1) upregulation], and protected against cell apoptosis (BAX downregulation).Conclusion: Autophagy could maintain the function of trophoblast cells by differentially regulating the expression of VEGFA and FLT1 and protecting against cell apoptosis at the maternal–fetal interface, potentially related to prevention of preeclampsia.

The Role of miR-181c in Mechanisms of Diabetes-Impaired Angiogenesis: An Emerging Therapeutic Target for Diabetic Vascular Complications

Diabetes mellitus is estimated to affect up to 700 million people by the year 2045, contributing to an immense health and economic burden. People living with diabetes have a higher risk of developing numerous debilitating vascular complications, leading to an increased need for medical care, a reduced quality of life and increased risk of early death. Current treatments are not satisfactory for many patients who suffer from impaired angiogenesis in response to ischaemia, increasing their risk of ischaemic cardiovascular conditions. These vascular pathologies are characterised by endothelial dysfunction and abnormal angiogenesis, amongst a host of impaired signaling pathways. Therapeutic stimulation of angiogenesis holds promise for the treatment of diabetic vascular complications that stem from impaired ischaemic responses. However, despite significant effort and research, there are no established therapies that directly stimulate angiogenesis to improve ischaemic complications such as ischaemic heart disease and peripheral artery disease, highlighting the immense unmet need. However, despite significant effort and research, there are no established therapies that directly stimulate angiogenesis in a clinical setting, highlighting the immense unmet need. MicroRNAs (miRNAs) are emerging as powerful targets for multifaceted diseases including diabetes and cardiovascular disease. This review highlights the potential role of microRNAs as therapeutic targets for rescuing diabetes-impaired angiogenesis, with a specific focus on miR-181c, which we have previously identified as an important angiogenic regulator. Here we summarise the pathways currently known to be regulated by miR-181c, which include the classical angiogenesis pathways that are dysregulated in diabetes, mitochondrial function and axonal guidance, and describe how these relate both directly and indirectly to angiogenesis. The pleiotropic actions of miR-181c across multiple key angiogenic signaling pathways and critical cellular processes highlight its therapeutic potential as a novel target for treating diabetic vascular complications.

Fli1+ cells transcriptional analysis reveals an Lmo2–Prdm16 axis in angiogenesis

A network of molecular factors drives the development, differentiation, and maintenance of endothelial cells. Friend leukemia integration 1 transcription factor (FLI1) is a bona fide marker of endothelial cells during early development. In zebrafish Tg(fli1:EGFP)y1, we identified two endothelial cell populations, high-fli1+ and low-fli1+, by the intensity of green fluorescent protein signal. By comparing RNA-sequencing analysis of non-fli1 expressing cells (fli1−) with these two (fli1+) cell populations, we identified several up-regulated genes, not previously recognized as important, during endothelial development. Compared with fli1− and low-fli1+ cells, high-fli1+ cells showed up-regulated expression of the zinc finger transcription factor PRDI-BF1 and RIZ homology domain containing 16 (prdm16). Prdm16 knockdown (KD) by morpholino in the zebrafish larva was associated with impaired angiogenesis and increased number of low-fli1+ cells at the expense of high-fli1+ cells. In addition, PRDM16 KD in endothelial cells derived from human-induced pluripotent stem cells impaired their differentiation and migration in vitro. Moreover, zebrafish mutants (mut) with loss of function for the oncogene LIM domain only 2 (lmo2) also showed reduced prdm16 gene expression combined with impaired angiogenesis. Prdm16 expression was reduced further in endothelial (CD31+) cells compared with CD31− cells isolated from lmo2-mutants (lmo2-mut) embryos. Chromatin immunoprecipitation–PCR demonstrated that Lmo2 binds to the promoter and directly regulates the transcription of prdm16. This work unveils a mechanism by which prdm16 expression is activated in endothelial cells by Lmo2 and highlights a possible therapeutic pathway by which to modulate endothelial cell growth and repair.

Proteomic Signature of Dysfunctional Circulating Endothelial Colony‐Forming Cells of Young Adults

Background A subpopulation of endothelial progenitor cells called endothelial colony‐forming cells (ECFCs) may offer a platform for cellular assessment in clinical studies because of their remarkable angiogenic and expansion potentials in vitro. Despite endothelial cell function being influenced by cardiovascular risk factors, no studies have yet provided a comprehensive proteomic profile to distinguish functional (ie, more angiogenic and expansive cells) versus dysfunctional circulating ECFCs of young adults. The aim of this study was to provide a detailed proteomic comparison between functional and dysfunctional ECFCs. Methods and Results Peripheral blood ECFCs were isolated from 11 subjects (45% men, aged 27±5 years) using Ficoll density gradient centrifugation. ECFCs expressed endothelial and progenitor surface markers and displayed cobblestone‐patterned morphology with clonal and angiogenic capacities in vitro. ECFCs were deemed dysfunctional if <1 closed tube formed during the in vitro tube formation assay and proliferation rate was <20%. Hierarchical functional clustering revealed distinct ECFC proteomic signatures between functional and dysfunctional ECFCs with changes in cellular mechanisms involved in exocytosis, vesicle transport, extracellular matrix organization, cell metabolism, and apoptosis. Targeted antiangiogenic proteins in dysfunctional ECFCs included SPARC (secreted protein acidic and rich in cysteine), CD36 (cluster of differentiation 36), LUM (lumican), and PTX3 (pentraxin‐related protein PYX3). Conclusions Circulating ECFCs with impaired angiogenesis and expansion capacities have a distinct proteomic profile and significant phenotype changes compared with highly angiogenic endothelial cells. Impaired angiogenesis in dysfunctional ECFCs may underlie the link between endothelial dysfunction and cardiovascular disease risks in young adults.