The Influence of Myeloid-Derived Suppressor Cell Expansion in Neuroinflammation and Neurodegenerative Diseases

The neuro-immune axis has a crucial function both during physiological and pathological conditions. Among the immune cells, myeloid-derived suppressor cells (MDSCs) exert a pivotal role in regulating the immune response in many pathological conditions, influencing neuroinflammation and neurodegenerative disease progression. In chronic neuroinflammation, MDSCs could lead to exacerbation of the inflammatory state and eventually participate in the impairment of cognitive functions. To have a complete overview of the role of MDSCs in neurodegenerative diseases, research on PubMed for articles using a combination of terms made with Boolean operators was performed. According to the search strategy, 80 papers were retrieved. Among these, 44 papers met the eligibility criteria. The two subtypes of MDSCs, monocytic and polymorphonuclear MDSCs, behave differently in these diseases. The initial MDSC proliferation is fundamental for attenuating inflammation in Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), but not in amyotrophic lateral sclerosis (ALS), where MDSC expansion leads to exacerbation of the disease. Moreover, the accumulation of MDSC subtypes in distinct organs changes during the disease. The proliferation of MDSC subtypes occurs at different disease stages and can influence the progression of each neurodegenerative disorder differently.

Organ-specific biological clocks: Ageotyping for personalized anti-aging medicine

Aging is a complex multidimensional, progressive remodeling process affecting multiple organ systems. While many studies have focused on studying aging across multiple organs, assessment of the contribution of individual organs to overall aging processes is a cutting-edge issue. An organ's biological age might influence the aging of other organs, revealing a multiorgan aging network. Recent data demonstrated a similar yet asynchronous inter-organs and inter-individuals progression of aging, thereby providing a foundation to track sources of declining health in old age. The integration of multiple omics with common clinical parameters through artificial intelligence has allowed the building of organ-specific aging clocks, which can predict the development of specific age-related diseases at high resolution. The peculiar individual aging-trajectory, referred to as ageotype, might provide a novel tool for a personalized anti-aging, preventive medicine. Here, we review data relative to biological aging clocks and omics-based data, suggesting different organ-specific aging rates. Additional research on longitudinal data, including young subjects and analyzing sex-related differences, should be encouraged to apply ageotyping analysis for preventive purposes in clinical practice.

The cell line models to study tyrosine kinase inhibitors in non-small cell lung cancer with mutations in the epidermal growth factor receptor: A scoping review

Non-Small Cell Lung Cancer (NSCLC) represents ∼85% of all lung cancers and ∼15-20% of them are characterized by mutations affecting the Epidermal Growth Factor Receptor (EGFR). For several years now, a class of tyrosine kinase inhibitors was developed, targeting sensitive mutations affecting the EGFR (EGFR-TKIs). To date, the main burden of the TKIs employment is due to the onset of resistance mutations. This scoping review aims to resume the current situation about the cell line models employed for the in vitro evaluation of resistance mechanisms induced by EGFR-TKIs in oncogene-addicted NSCLC. Adenocarcinoma results the most studied NSCLC histotype with the H1650, H1975, HCC827 and PC9 mutated cell lines, while Gefitinib and Osimertinib the most investigated inhibitors. Overall, data collected frame the current advancement of this topic, showing a plethora of approaches pursued to overcome the TKIs resistance, from RNA-mediated strategies to the innovative combination therapies.

Role of SLC7A11/xCT in Ovarian Cancer

Ovarian cancer is one of the most dangerous gynecologic cancers worldwide and has a high fatality rate due to diagnosis at an advanced stage of the disease as well as a high recurrence rate due to the occurrence of chemotherapy resistance. In fact, chemoresistance weakens the therapeutic effects, worsening the outcome of this pathology. Solute Carrier Family 7 Member 11 (SLC7A11, also known as xCT) is the functional subunit of the Xc- system, an anionic L-cystine/L-glutamate antiporter expressed on the cell surface. SLC7A11 expression is significantly upregulated in several types of cancers in which it can inhibit ferroptosis and favor cancer cell proliferation, invasion and chemoresistance. SLC7A11 expression is also increased in ovarian cancer tissues, suggesting a possible role of this protein as a therapeutic target. In this review, we provide an overview of the current literature regarding the role of SLC7A11 in ovarian cancer to provide new insights on SLC7A11 modulation and evaluate the potential role of SLC7A11 as a therapeutic target.

Senescent Endothelial Cells Sustain Their Senescence-Associated Secretory Phenotype (SASP) through Enhanced Fatty Acid Oxidation

Cellular senescence is closely linked to endothelial dysfunction, a key factor in age-related vascular diseases. Senescent endothelial cells exhibit a proinflammatory phenotype known as SASP, leading to chronic inflammation (inflammaging) and vascular impairments. Albeit in a state of permanent growth arrest, senescent cells paradoxically display a high metabolic activity. The relationship between metabolism and inflammation is complex and varies across cell types and senescence inductions. While some cell types shift towards glycolysis during senescence, others favor oxidative phosphorylation (OXPHOS). Despite the high availability of oxygen, quiescent endothelial cells (ECs) tend to rely on glycolysis for their bioenergetic needs. However, there are limited data on the metabolic behavior of senescent ECs. Here, we characterized the metabolic profiles of young and senescent human umbilical vein endothelial cells (HUVECs) to establish a possible link between the metabolic status and the proinflammatory phenotype of senescent ECs. Senescent ECs internalize a smaller amount of glucose, have a lower glycolytic rate, and produce/release less lactate than younger cells. On the other hand, an increased fatty acid oxidation activity was observed in senescent HUVECs, together with a greater intracellular content of ATP. Interestingly, blockade of glycolysis with 2-deoxy-D-glucose in young cells resulted in enhanced production of proinflammatory cytokines, while the inhibition of carnitine palmitoyltransferase 1 (CPT1), a key rate-limiting enzyme of fatty acid oxidation, ameliorated the SASP in senescent ECs. In summary, metabolic changes in senescent ECs are complex, and this research seeks to uncover potential strategies for modulating these metabolic pathways to influence the SASP.

Anti-Inflammatory Effects of Olive Leaf Extract and Its Bioactive Compounds Oleacin and Oleuropein-Aglycone on Senescent Endothelial and Small Airway Epithelial Cells

Olive tree by-products have been deeply studied as an invaluable source of bioactive compounds. Several in vitro and in vivo studies showed that olive leaf extract (OLE) has anti-inflammatory and antioxidant properties. Here, we wanted to assess the valuable benefits of two less-studied OLE components-3,4-DHPEA-EDA (Oleacin, OC) and 3,4-DHPEA-EA (Oleuropein-Aglycone, OA)-directly purified from OLE using a cost-effective and environmentally sustainable method, in line with the principles of circular economy. OLE, OC and OA were then tested in human cellular models involved in acute and chronic inflammation and in the pathogenesis of viral infections, i.e., lipopolysaccharide (LPS)-treated monocyte/macrophages (THP-1) and endothelial cells (HUVECs), senescent HUVECs and Poly(I:C)-treated small airway epithelial cells (hSAECs). Results showed that OC and OA are efficient in ameliorating almost all of the pro-inflammatory readouts (IL-1β, TNF-α, IL-8, ICAM, VCAM) and reducing the release of IL-6 in all the cellular models. In hSAECs, they also modulate the expression of SOD2, NF-kB and also ACE2 and TMPRSS2, whose expression is required for SARS-CoV-2 virus entry. Overall, these data suggest the usefulness of OLE, OC and OA in controlling or preventing inflammatory responses, in particular those associated with viral respiratory infections and aging.

Pro-Osteogenic and Anti-Inflammatory Synergistic Effect of Orthosilicic Acid, Vitamin K2, Curcumin, Polydatin and Quercetin Combination in Young and Senescent Bone Marrow-Derived Mesenchymal Stromal Cells

During aging, bone marrow mesenchymal stromal cells (MSCs)-the precursors of osteoblasts-undergo cellular senescence, losing their osteogenic potential and acquiring a pro-inflammatory secretory phenotype. These dysfunctions cause bone loss and lead to osteoporosis. Prevention and intervention at an early stage of bone loss are important, and naturally active compounds could represent a valid help in addition to diet. Here, we tested the hypothesis that the combination of two pro-osteogenic factors, namely orthosilicic acid (OA) and vitamin K2 (VK2), and three other anti-inflammatory compounds, namely curcumin (CUR), polydatin (PD) and quercetin (QCT)-that mirror the nutraceutical BlastiMin Complex^® (Mivell, Italy)-would be effective in promoting MSC osteogenesis, even of replicative senescent cells (sMSCs), and inhibiting their pro-inflammatory phenotype in vitro. Results showed that when used at non-cytotoxic doses, (i) the association of OA and VK2 promoted MSC differentiation into osteoblasts, even when cultured without other pro-differentiating factors; and (ii) CUR, PD and QCT exerted an anti-inflammatory effect on sMSCs, and also synergized with OA and VK2 in promoting the expression of the pivotal osteogenic marker ALP in these cells. Overall, these data suggest a potential role of using a combination of all of these natural compounds as a supplement to prevent or control the progression of age-related osteoporosis.

Sensitivity and specificity of in vivo COVID-19 screening by detection dogs: Results of the C19-Screendog multicenter study

Trained dogs can recognize the volatile organic compounds contained in biological samples of patients with COVID-19 infection. We assessed the sensitivity and specificity of in vivo SARS-CoV-2 screening by trained dogs. We recruited five dog-handler dyads. In the operant conditioning phase, the dogs were taught to distinguish between positive and negative sweat samples collected from volunteers' underarms in polymeric tubes. The conditioning was validated by tests involving 16 positive and 48 negative samples held or worn in such a way that the samples were invisible to the dog and handler. In the screening phase the dogs were led by their handlers to a drive-through facility for in vivo screening of volunteers who had just received a nasopharyngeal swab from nursing staff. Each volunteer who had already swabbed was subsequently tested by two dogs, whose responses were recorded as positive, negative, or inconclusive. The dogs' behavior was constantly monitored for attentiveness and wellbeing. All the dogs passed the conditioning phase, their responses showing a sensitivity of 83-100% and a specificity of 94-100%. The in vivo screening phase involved 1251 subjects, of whom 205 had a COVID-19 positive swab and two dogs per each subject to be screened. Screening sensitivity and specificity were respectively 91.6-97.6% and 96.3-100% when only one dog was involved, whereas combined screening by two dogs provided a higher sensitivity. Dog wellbeing was also analyzed: monitoring of stress and fatigue suggested that the screening activity did not adversely impact the dogs' wellbeing. This work, by screening a large number of subjects, strengthen recent findings that trained dogs can discriminate between COVID-19 infected and healthy human subjects and introduce two novel research aspects: i) assessement of signs of fatigue and stress in dogs during training and testing, and ii) combining screening by two dogs to improve detection sensitivity and specificity. Using some precautions to reduce the risk of infection and spillover, in vivo COVID-19 screening by a dog-handler dyad can be suitable to quickly screen large numbers of people: it is rapid, non-invasive and economical, since it does not involve actual sampling, lab resources or waste management, and is suitable to screen large numbers of people.

The Combination of Natural Molecules Naringenin, Hesperetin, Curcumin, Polydatin and Quercetin Synergistically Decreases SEMA3E Expression Levels and DPPIV Activity in In Vitro Models of Insulin Resistance

Type 2 diabetes mellitus (T2DM) is a disease characterized by a prolonged hyperglycemic condition caused by insulin resistance mechanisms in muscle and liver, reduced insulin production by pancreatic β cells, and a chronic inflammatory state with increased levels of the pro-inflammatory marker semaphorin 3E. Phytochemicals present in several foods have been used to complement oral hypoglycemic drugs for the management of T2DM. Notably, dipeptidyl peptidase IV (DPPIV) inhibitors have demonstrated efficacy in the treatment of T2DM. Our study aimed to investigate, in in vitro models of insulin resistance, the ability of the flavanones naringenin and hesperetin, used alone and in combination with the anti-inflammatory natural molecules curcumin, polydatin, and quercetin, to counteract the insulin resistance and pro-inflammatory molecular mechanisms that are involved in T2DM development. Our results show for the first time that the combination of naringenin, hesperetin, curcumin, polydatin, and quercetin (that mirror the nutraceutical formulation GliceFen^®, Mivell, Italy) synergistically decreases expression levels of the pro-inflammatory gene SEMA3E in insulin-resistant HepG2 cells and synergistically decreases DPPIV activity in insulin-resistant Hep3B cells, indicating that the combination of these five phytochemicals is able to inhibit pro-inflammatory and insulin resistance molecular mechanisms and could represent an effective innovative complementary approach to T2DM pharmacological treatment.

MiR-422a promotes adipogenesis via MeCP2 downregulation in human bone marrow mesenchymal stem cells

Methyl-CpG binding protein 2 (MeCP2) is a ubiquitous transcriptional regulator. The study of this protein has been mainly focused on the central nervous system because alterations of its expression are associated with neurological disorders such as Rett syndrome. However, young patients with Rett syndrome also suffer from osteoporosis, suggesting a role of MeCP2 in the differentiation of human bone marrow mesenchymal stromal cells (hBMSCs), the precursors of osteoblasts and adipocytes. Here, we report an in vitro downregulation of MeCP2 in hBMSCs undergoing adipogenic differentiation (AD) and in adipocytes of human and rat bone marrow tissue samples. This modulation does not depend on MeCP2 DNA methylation nor on mRNA levels but on differentially expressed miRNAs during AD. MiRNA profiling revealed that miR-422a and miR-483-5p are upregulated in hBMSC-derived adipocytes compared to their precursors. MiR-483-5p, but not miR-422a, is also up-regulated in hBMSC-derived osteoblasts, suggesting a specific role of the latter in the adipogenic process. Experimental modulation of intracellular levels of miR-422a and miR-483-5p affected MeCP2 expression through direct interaction with its 3' UTR elements, and the adipogenic process. Accordingly, the knockdown of MeCP2 in hBMSCs through MeCP2-targeting shRNA lentiviral vectors increased the levels of adipogenesis-related genes. Finally, since adipocytes released a higher amount of miR-422a in culture medium compared to hBMSCs we analyzed the levels of circulating miR-422a in patients with osteoporosis-a condition characterized by increased marrow adiposity-demonstrating that its levels are negatively correlated with T- and Z-scores. Overall, our findings suggest that miR-422a has a role in hBMSC adipogenesis by downregulating MeCP2 and its circulating levels are associated with bone mass loss in primary osteoporosis.

Replicative Senescence-Associated LINE1 Methylation and LINE1-Alu Expression Levels in Human Endothelial Cells

One of the main challenges of current research on aging is to identify the complex epigenetic mechanisms involved in the acquisition of the cellular senescent phenotype. Despite some evidence suggested that epigenetic changes of DNA repetitive elements, including transposable elements (TE) sequences, are associated with replicative senescence of fibroblasts, data on different types of cells are scarce. We previously analysed genome-wide DNA methylation of young and replicative senescent human endothelial cells (HUVECs), highlighting increased levels of demethylated sequences in senescent cells. Here, we aligned the most significantly demethylated single CpG sites to the reference genome and annotated their localization inside TE sequences and found a significant hypomethylation of sequences belonging to the Long-Interspersed Element-1 (LINE-1 or L1) subfamilies L1M, L1P, and L1HS. To verify the hypothesis that L1 demethylation could be associated with increased transcription/activation of L1s and/or Alu elements (non-autonomous retroelements that usually depend on L1 sequences for reverse transcription and retrotransposition), we quantified the RNA expression levels of both L1 (generic L1 elements or site-specific L1PA2 on chromosome 14) and Alu elements in young and senescent HUVECs and human dermal fibroblasts (NHDFs). The RNA expression of Alu and L1 sequences was significantly increased in both senescent HUVECs and NHDFs, whereas the RNA transcript of L1PA2 on chromosome 14 was not significantly modulated in senescent cells. Moreover, we found an increased amount of TE DNA copies in the cytoplasm of senescent HUVECs and NHDFs. Our results support the hypothesis that TE, which are significantly increased in senescent cells, could be retrotranscribed to DNA sequences.

Prognostic value of soluble ST2, high-sensitivity cardiac troponin, and NT-proBNP in type 2 diabetes: a 15-year retrospective study

Background

Patients with type 2 diabetes (T2DM) present an increased risk of cardiovascular (CV) disease and excess CV-related mortality. Beyond the established role of brain natriuretic peptide (BNP) and cardiac troponins (cTn), other non-cardiac-specific biomarkers are emerging as predictors of CV outcomes in T2DM.

Methods

Serum levels of soluble suppression of tumorigenesis 2 (sST2), high-sensitivity (hs)-cTnI, and N-terminal (NT)-proBNP were assessed in 568 patients with T2DM and 115 healthy controls (CTR). Their association with all-cause mortality and the development of diabetic complications was tested in T2DM patients over a median follow-up of 16.8 years using Cox models and logistic regressions.

Results

sST2 followed an increasing trend from CTR to uncomplicated T2DM patients (T2DM-NC) to patients with at least one complication (T2DM-C), while hs-cTnI was significantly higher in T2DM-C compared to CTR but not to T2DM-NC. A graded association was found between sST2 (HR 2.76 [95% CI 1.20–6.33] for ≥ 32.0 ng/mL and 2.00 [1.02–3.94] for 16.5–32.0 ng/mL compared to < 16.5 ng/mL, C-statistic = 0.729), NT-proBNP (HR 2.04 [1.90–4.55] for ≥ 337 ng/L and 1.48 [1.05–2.10] for 89–337 ng/L compared to < 89 ng/L, C-statistic = 0.741), and 15-year mortality in T2DM, whereas increased mortality was observed in patients with hs-cTnI ≥ 7.8 ng/L (HR 1.63 [1.01–2.62]). A ‘cardiac score’ based on the combination of sST2, hs-cTnI, and NT-proBNP was significantly associated with all-cause mortality (HR 1.35 [1.19–1.53], C-statistic = 0.739) and development of CV events.

Conclusions

sST2, hs-cTnI, and NT-proBNP are associated with 15-year mortality and onset of CV events in T2DM. The long-term prognostic value of sST2 and its ability to track variables related to insulin resistance and associated metabolic disorders support its implementation into routine clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01616-3.

Circulating biomarkers of inflammaging as potential predictors of COVID-19 severe outcomes

The COVID-19 pandemic caused by SARS-CoV-2 infection has been of unprecedented clinical and socio-economic worldwide relevance. The case fatality rate for COVID-19 grows exponentially with age and the presence of comorbidities. In the older patients, COVID-19 manifests predominantly as a systemic disease associated with immunological, inflammatory, and procoagulant responses. Timely diagnosis and risk stratification are crucial steps to define appropriate therapies and reduce mortality, especially in the older patients. Chronically and systemically activated innate immune responses and impaired antiviral responses have been recognized as the results of a progressive remodeling of the immune system during aging, which can be described by the words 'immunosenescence' and 'inflammaging'. These age-related features of the immune system were highlighted in patients affected by COVID-19 with the poorest clinical outcomes, suggesting that the mechanisms underpinning immunosenescence and inflammaging could be relevant for COVID-19 pathogenesis and progression. Increasing evidence suggests that senescent myeloid and endothelial cells are characterized by the acquisition of a senescence-associated pro-inflammatory phenotype (SASP), which is considered as the main culprit of both immunosenescence and inflammaging. Here, we reviewed this evidence and highlighted several circulating biomarkers of inflammaging that could provide additional prognostic information to stratify COVID-19 patients based on the risk of severe outcomes.

Anti-inflammatory effect of SGLT-2 inhibitors via uric acid and insulin

Sodium-glucose cotransporter 2 (SGLT-2) inhibitors (i) reduce cardiovascular and renal events in patients with and without type 2 diabetes (T2D). However, the underlying mechanisms are debated. Low-grade inflammation (LGI) is a key driver of vascular complications, suggested to be attenuated by SGLT-2i in animal models. Based on a specific working hypothesis, here we investigated the net effect of SGLT-2i on LGI in patients with T2D and the possible underlying mechanism. We enrolled patients with T2D treated either with a stable therapy with SGLT-2i or with other glucose-lowering drugs (GLD) (n = 43 per group after matching for a range of pro-inflammatory variables), and tested hs-CRP and interleukin (IL)-6 as primary variables of interest. Patients treated with SGLT-2i had lower circulating levels of IL-6, a prototypical marker of LGI, but also of uric acid and fasting insulin, compared with patients treated with other GLD. Then, to explore whether uric acid and insulin might mediate the effect of SGLT-2i on IL-6, we tested physiologically pertinent doses of these two molecules (i.e. 0.5 mM uric acid and 1 nM insulin) in two in vitro models of LGI, i.e. monocytes (THP-1) treated with LPS and endothelial cells (HUVEC) exposed to hyperglycaemia. Results from in vitro models supported a pro-inflammatory role for uric acid and its combination with insulin in monocytes and for uric acid alone in hyperglycaemia-stimulated endothelial cells. On the contrary, we observed no drug-intrinsic, anti-inflammatory effect for dapagliflozin, empagliflozin, and canagliflozin in the same models. Overall, these results suggest that SGLT-2i possess a tangible activity against LGI, an effect possibly mediated by their ability to lower uric acid and insulin concentrations and that juxtaposes other proposed mechanisms in explaining the observed benefit of this class on cardiovascular and renal endpoints.

MicroRNAs as Factors in Bidirectional Crosstalk Between Mitochondria and the Nucleus During Cellular Senescence

Mitochondria are essential organelles that generate most of the chemical energy to power the cell through ATP production, thus regulating cell homeostasis. Although mitochondria have their own independent genome, most of the mitochondrial proteins are encoded by nuclear genes. An extensive bidirectional communication network between mitochondria and the nucleus has been discovered, thus making them semi-autonomous organelles. The nucleus-to-mitochondria signaling pathway, called Anterograde Signaling Pathway can be deduced, since the majority of mitochondrial proteins are encoded in the nucleus, less is known about the opposite pathway, the so-called mitochondria-to-nucleus retrograde signaling pathway. Several studies have demonstrated that non-coding RNAs are essential “messengers” of this communication between the nucleus and the mitochondria and that they might have a central role in the coordination of important mitochondrial biological processes. In particular, the finding of numerous miRNAs in mitochondria, also known as mitomiRs, enabled insights into their role in mitochondrial gene transcription. MitomiRs could act as important mediators of this complex crosstalk between the nucleus and the mitochondria. Mitochondrial homeostasis is critical for the physiological processes of the cell. Disruption at any stage in their metabolism, dynamics and bioenergetics could lead to the production of considerable amounts of reactive oxygen species and increased mitochondrial permeability, which are among the hallmarks of cellular senescence. Extensive changes in mitomiR expression and distribution have been demonstrated in senescent cells, those could possibly lead to an alteration in mitochondrial homeostasis. Here, we discuss the emerging putative roles of mitomiRs in the bidirectional communication pathways between mitochondria and the nucleus, with a focus on the senescence-associated mitomiRs.

miR-21 and miR-146a: The microRNAs of inflammaging and age-related diseases

The first paper on "inflammaging" published in 2001 paved the way for a unifying theory on how and why aging turns out to be the main risk factor for the development of the most common age-related diseases (ARDs). The most exciting challenge on this topic was explaining how systemic inflammation steeps up with age and why it shows different rates among individuals of the same chronological age. The "epigenetic revolution" in the past twenty years conveyed that the assessment of the individual genetic make-up is not enough to depict the trajectories of age-related inflammation. Accordingly, others and we have been focusing on the role of non-coding RNA, i.e. microRNAs (miRNAs), in inflammaging. The results obtained in the latest 10 years underpinned the key role of a miRNA subset that we have called inflammamiRs, owing to their ability to master (NF-κB)-driven inflammatory pathways. In this review, we will focus on two inflammamiRs, i.e. miR-21-5p and miR-146a-5p, which target a variety of molecules belonging to the NF-κB/NLRP3 pathways. The interplay between miR-146a-5p and IL-6 in the context of aging and ARDs will also be highlighted. We will also provide the most relevant evidence suggesting that circulating inflammamiRs, along with IL-6, can measure the degree of inflammaging.

Anti-SASP and anti-inflammatory activity of resveratrol, curcumin and β-caryophyllene association on human endothelial and monocytic cells

A challenging and promising new branch of aging-related research fields is the identification of natural compounds able to modulate the senescence-associated secretory phenotype (SASP), which characterizes senescent cells and can contribute to fuel the inflammaging. We investigated both the anti-SASP and anti-inflammatory activities of a nutritional supplement, namely Fenoxidol™, composed of turmeric extract bioCurcumin (bCUR), Polydatin (the natural glycosylated precursor of Resveratrol-RSV), and liposomal β-caryophyllene (BCP), in two human cellular models, such as the primary endothelial cell line, HUVECs and the monocytic cell line, THP-1. Replicative and Doxorubicin-induced senescent HUVECs, both chosen as cellular models of SASP, and lipopolysaccharides (LPS)-stimulated THP-1, selected as a model of the inflammatory response, were treated with the three single natural compounds or with a combination of them (MIX). In both senescent HUVEC models, MIX treatment significantly reduced IL-1β and IL-6 expression levels and p16^ink4a protein, and also increased SIRT1 protein level, as well as downregulated miR-146a and miR-21 expression, two of the so-called inflamma-miRNAs, more effectively than the single compounds. In THP-1 cells stimulated with LPS, the MIX showed a significant effect in decreasing IL-1β, IL-6, TNF-α, and miR-146a expression levels and Caspase-1 activation, in association with an up-regulation of SIRT1 protein, compared to the single compounds. Overall, our results suggest that the three analysed compounds can have a combined effect in restraining SASP in senescent HUVECs as well as the inflammatory response in LPS-stimulated THP-1 cells.

CD31+ Extracellular Vesicles From Patients With Type 2 Diabetes Shuttle a miRNA Signature Associated With Cardiovascular Complications

Innovative biomarkers are needed to improve the management of patients with type 2 diabetes mellitus (T2DM). Blood circulating miRNAs have been proposed as a potential tool to detect T2DM complications, but the lack of tissue specificity, among other reasons, has hampered their translation to clinical settings. Extracellular vesicle (EV)-shuttled miRNAs have been proposed as an alternative approach. Here, we adapted an immunomagnetic bead-based method to isolate plasma CD31⁺ EVs to harvest vesicles deriving from tissues relevant for T2DM complications. Surface marker characterization showed that CD31⁺ EVs were also positive for a range of markers typical of both platelets and activated endothelial cells. After characterization, we quantified 11 candidate miRNAs associated with vascular performance and shuttled by CD31⁺ EVs in a large (n = 218) cross-sectional cohort of patients categorized as having T2DM without complications, having T2DM with complications, and control subjects. We found that 10 of the tested miRNAs are affected by T2DM, while the signature composed by miR-146a, -320a, -422a, and -451a efficiently identified T2DM patients with complications. Furthermore, another CD31⁺ EV-shuttled miRNA signature, i.e., miR-155, -320a, -342-3p, -376, and -422a, detected T2DM patients with a previous major adverse cardiovascular event. Many of these miRNAs significantly correlate with clinical variables held to play a key role in the development of complications. In addition, we show that CD31⁺ EVs from patients with T2DM are able to promote the expression of selected inflammatory mRNAs, i.e., CCL2, IL-1α, and TNFα, when administered to endothelial cells in vitro. Overall, these data suggest that the miRNA cargo of plasma CD31⁺ EVs is largely affected by T2DM and related complications, encouraging further research to explore the diagnostic potential and the functional role of these alterations.

Long-term exposure of human endothelial cells to metformin modulates miRNAs and isomiRs

Increasing evidence suggest that the glucose-lowering drug metformin exerts a valuable anti-senescence role. The ability of metformin to affect the biogenesis of selected microRNAs (miRNAs) was recently suggested. MicroRNA isoforms (isomiRs) are distinct variations of miRNA sequences, harboring addition or deletion of one or more nucleotides at the 5′ and/or 3′ ends of the canonical miRNA sequence. We performed a comprehensive analysis of miRNA and isomiR profile in human endothelial cells undergoing replicative senescence in presence of metformin. Metformin treatment was associated with the differential expression of 27 miRNAs (including miR-100-5p, -125b-5p, -654-3p, -217 and -216a-3p/5p). IsomiR analysis revealed that almost 40% of the total miRNA pool was composed by non-canonical sequences. Metformin significantly affects the relative abundance of 133 isomiRs, including the non-canonical forms of the aforementioned miRNAs. Pathway enrichment analysis suggested that pathways associated with proliferation and nutrient sensing are modulated by metformin-regulated miRNAs and that some of the regulated isomiRs (e.g. the 5′ miR-217 isomiR) are endowed with alternative seed sequences and share less than half of the predicted targets with the canonical form. Our results show that metformin reshapes the senescence-associated miRNA/isomiR patterns of endothelial cells, thus expanding our insight into the cell senescence molecular machinery.

Prevalence of residual inflammatory risk and associated clinical variables in patients with type 2 diabetes

Residual inflammatory risk (RIR) is defined as persistent circulating levels of high sensitivity C-reactive protein (hs-CRP) >2 mg/L despite an optimal (<70 mg/dL) control of LDL-cholesterol (LDL-C) and represents an emerging risk factor for the development of cardiovascular events in patients at high risk of atherosclerosis. Sparse data are available regarding the prevalence of RIR in patients with type 2 diabetes (T2D) and the clinical variables associated with hs-CRP elevation. Here, we report data from a well-characterized cohort of patients with T2D (n = 511) stratified for statins use, LDL-C goal attainment and prevalent T2D complications. Statins use and having at-target LDL-C partially affect the number of patients with inflammatory risk when compared with the whole T2D population, with an RIR prevalence of 39.2%. Among the spectra of complications, only patients with nephropathy had a higher prevalence of inflammatory risk. Total cholesterol, non-HDL-cholesterol, triglycerides, body mass index and waist-hip ratio were associated with hs-CRP, with an increased magnitude in at-target patients. Conversely, glucose-related variables were strongly associated with hs-CRP only in at-target patients, overall suggesting glycaemic control, insulin resistance, non-LDL-C lipid variables and especially central obesity as possible contributors to RIR in patients with T2D and LDL-C <70 mg/dL.

Pleiotropic effects of polyphenols on glucose and lipid metabolism: Focus on clinical trials

Epidemiological evidence from observational studies suggests that dietary polyphenols (PPs) - phytochemicals found in a variety of plant-based foods - can reduce the risk of developing type 2 diabetes mellitus (T2DM). Clinical trials have also indicated that PPs may help manage the two key features of T2DM, hyperglycemia and dyslipidemia. Since the incidence of T2DM is dramatically increasing worldwide, identifying food-based approaches that can reduce the risk of developing it and help manage its main risk factors in early-stage disease has clinical and socioeconomic relevance. After a brief overview of current epidemiological data on the incidence of T2DM in individuals consuming PP-rich diets, we review the evidence from clinical trials investigating PP-enriched foods and/or PP-based nutraceutical compounds, report their main results, and highlight the knowledge gaps that should be bridged to enhance our understanding of the role of PPs in T2DM development and management.

Small extracellular vesicles deliver miR-21 and miR-217 as pro-senescence effectors to endothelial cells

The role of epigenetics in endothelial cell senescence is a cutting-edge topic in ageing research. However, little is known of the relative contribution to pro-senescence signal propagation provided by microRNAs shuttled by extracellular vesicles (EVs) released from senescent cells. Analysis of microRNA and DNA methylation profiles in non-senescent (control) and senescent (SEN) human umbilical vein endothelial cells (HUVECs), and microRNA profiling of their cognate small EVs (sEVs) and large EVs demonstrated that SEN cells released a significantly greater sEV number than control cells. sEVs were enriched in miR-21-5p and miR-217, which target DNMT1 and SIRT1. Treatment of control cells with SEN sEVs induced a miR-21/miR-217-related impairment of DNMT1-SIRT1 expression, the reduction of proliferation markers, the acquisition of a senescent phenotype and a partial demethylation of the locus encoding for miR-21. MicroRNA profiling of sEVs from plasma of healthy subjects aged 40-100 years showed an inverse U-shaped age-related trend for miR-21-5p, consistent with senescence-associated biomarker profiles. Our findings suggest that miR-21-5p/miR-217 carried by SEN sEVs spread pro-senescence signals, affecting DNA methylation and cell replication.

Where Metabolism Meets Senescence: Focus on Endothelial Cells

Despite the decline in their proliferative potential, senescent cells display a high metabolic activity. Senescent cells have been shown to acquire a more glycolytic state even in presence of high oxygen levels, in a way similar to cancer cells. The diversion of pyruvate, the final product of glycolysis, away from oxidative phosphorylation results in an altered bioenergetic state and may occur as a response to the enhanced oxidative stress caused by the accumulation of dysfunctional mitochondria. This metabolic shift leads to increased AMP/ATP and ADP/ATP ratios, to the subsequent AMPK activation, and ultimately to p53-mediated growth arrest. Mounting evidences suggest that metabolic reprogramming is critical to direct considerable amounts of energy toward specific activities related to the senescent state, including the senescence-associated secretory phenotype (SASP) and the modulation of immune responses within senescent cell tissue microenvironment. Interestingly, despite the relative abundance of oxygen in the vascular compartment, healthy endothelial cells (ECs) produce most of their ATP content from the anaerobic conversion of glucose to lactate. Their high glycolytic rate further increases during senescence. Alterations in EC metabolism have been identified in age-related diseases (ARDs) associated with a dysfunctional vasculature, including atherosclerosis, type 2 diabetes and cardiovascular diseases. In particular, higher production of reactive oxygen species deriving from a variety of enzymatic sources, including uncoupled endothelial nitric oxide synthase and the electron transport chain, causes DNA damage and activates the NAD+-consuming enzymes polyADP-ribose polymerase 1 (PARP1). These non-physiological mechanisms drive the impairment of the glycolytic flux and the diversion of glycolytic intermediates into many pathological pathways. Of note, accumulation of senescent ECs has been reported in the context of ARDs. Through their pro-oxidant, pro-inflammatory, vasoconstrictor, and prothrombotic activities, they negatively impact on vascular physiology, promoting both the onset and development of ARDs. Here, we review the current knowledge on the cellular senescence-related metabolic changes and their contribution to the mechanisms underlying the pathogenesis of ARDs, with a particular focus on ECs. Moreover, current and potential interventions aimed at modulating EC metabolism, in order to prevent or delay ARD onset, will be discussed.

The mitomiR/Bcl-2 axis affects mitochondrial function and autophagic vacuole formation in senescent endothelial cells

During senescence, cells undergo distinctive biochemical and morphological changes and become dysfunctional. MiRNAs are involved in the senescence process and specific miRNAs can localize to mitochondria (mitomiRs). We hypothesized that part of the typical alterations of senescence may depends on mitomiRs deregulation. Therefore, we thoroughly explored the phenotype of human endothelial cells undergoing replicative senescence (sHUVECs) and observed elongated/branched mitochondria, accumulation of autophagic vacuoles (AVs), increased ROS and IL-1β production and reduced expression of Bcl-2 compared to younger cells (yHUVECs). Despite these pro-apoptotic features, sHUVECs are more resistant to serum deprivation, conceivably due to development of pro-survival strategies such as upregulation of Bcl-xL and Survivin. We demonstrate that mitomiR-181a, -34a, and -146a, are overexpressed and localize to mitochondria in sHUVECs compared with yHUVECs and that they: i) down-regulate Bcl-2, ii) induce permeability transition pore opening and activation of caspase-1 and 3, iii) affect sensitivity to apoptosis and iv) promote the conversion of LC3-I to LC3-II. Overall, we document for the first time that some mitomiRs can act as mediators of the multiple but functionally linked biochemical and morphological changes that characterize aging cells and that they can promote different cellular outcomes according to the senescence status of the cell.

Age-related M1/M2 phenotype changes in circulating monocytes from healthy/unhealthy individuals

Macrophage polarization is a candidate biomarker of disease-related inflammatory status, but its modulation during aging has not been investigated. To do this, the M1/M2 profile was assessed by CD80/CD163 gating in classical (CD14⁺⁺CD16^-), intermediate (CD14⁺⁺CD16⁺), and non-classical (CD14^lowCD16⁺) monocytes from 31 healthy subjects (CTRs) of different ages. Cytofluorimetric analysis showed a significantly different CD80/CD163 distribution in the three subsets, as more than 80% of classical and intermediate monocytes were CD80⁺CD163⁺, whereas most non-classical monocytes were CD80^-CD163^- and CD163⁺. Non-classical CD163⁺ monocytes were significantly higher whereas classical CD163⁺ and CD80^-CD163^- monocytes significantly lower in older than younger CTRs (cut-off, 65 years), suggesting different age-related trends for M2 subsets. To establish whether an M1/M2 imbalance could be associated with disease, 21 patients with acute myocardial infarction (AMI) were compared with older CTRs. The AMI patients showed a significantly decreased proportion of CD163⁺CD80⁺ and an increased proportion of CD163⁺ and CD163^-CD80^- cells among classical monocytes, opposite trends to those observed in healthy aging. Moreover, a significantly greater proportion of intermediate and non-classical CD80⁺ monocytes suggested a shift to a pro-inflammatory phenotype. Overall, CD163/CD80 cytofluorimetric characterization of circulating monocytes provides additional information about their polarization and could be an innovative tool to monitor aging.

Differential microRNA expression between decidual and peripheral blood natural killer cells in early pregnancy

STUDY QUESTION

Have decidual natural killer (dNK) cells a different microRNA (miRNA or miR) expression pattern compared to NK cells circulating in the peripheral blood (pb) of healthy pregnant women in the first trimester of gestation?

SUMMARY ANSWER

dNK cells have a unique miRNA profile, showing exclusive expression of a set of miRNAs and significant up- or down-regulation of most of the miRNAs shared with pbNK cells.

WHAT IS KNOWN ALREADY

dNK cells differ from pbNK cells both phenotypically and functionally, and their origin is still debated. Many studies have indicated that miRNAs regulate several important aspects of NK cell biology, such as development, activation and effector functions.

STUDY DESIGN, SIZE, DURATION

Decidua basalis and peripheral blood specimens were collected from women (n = 7) undergoing voluntary termination of gestation in the first trimester of pregnancy. dNK and pbNK cells were then highly purified by cell sorting.

PARTICIPANTS/MATERIALS, SETTING, METHODS

miRNAs expression was analysed by quantitative RT-PCR (qRT-PCR)-based arrays using RNA purified from freshly isolated and highly purified pbNK and dNK cells. Results from arrays were validated by qRT-PCR assays. The bioinformatics tool ingenuity pathway analysis (IPA) was applied to determine the cellular network targeted by validated miRNAs and the correlated biological functions.

MAIN RESULTS AND THE ROLE OF CHANCE

Herein, we identified the most differentially expressed miRNAs in NK cells isolated from peripheral blood and uterine decidua of pregnant women. We found that 36 miRNAs were expressed only in dNK cells and two miRNAs only in pbNK cells. Moreover, 48 miRNAs were commonly expressed by both NK cell preparations although at different levels: 28 were upregulated in dNK cells, while 15 were downregulated compared to pbNK cells. Validation of a selected set (n = 11) of these miRNAs confirmed the differential expression of nine miRNAs: miR-10b and miR-214 expressed only in dNK cells and miR-200a-3p expressed only in pbNK cells; miR-130b-3p, miR-125a-5p, miR-212-3p and miR-454 were upregulated while miR-210-3p and miR-132 were downregulated in dNK cells compared to pbNK cells. IPA network analysis identified a single network connecting all the miRNAs as well as their significant involvement in several classes of functions: 'Organismal injury, Reproductive system disease, Inflammatory disease' and 'Cellular development'. These miRNAs target molecules such as argonaute 2, tumour protein p53, insulin and other genes that belong to the same network and significantly influence cell differentiation and pregnancy.

LIMITATIONS, REASONS FOR CAUTION

In the present study, the cellular network and biological functions modulated by miRNAs differentially expressed in dNK and pbNK cells were identified by IPA considering only molecules and relationships that were with confidence 'experimentally observed' in leucocytes. The decidual and pbNK cells that were analysed here are a heterogeneous population and further study will help to disentangle whether there are differences in miRNA production by the different subsets of NK cells.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study describing a different miRNA expression profile in dNK cells compared to matched pbNK cells during the first trimester of pregnancy. Our findings improved the body of knowledge on dNK cell biology and strongly suggest further investigation into the roles of miRNAs that are differentially expressed in human dNK compared to pbNK cells. Our results suggest that specific miRNAs can modulate dNK cell origin and functions, highlighting a potential role of this miRNA signature in human development and diseases.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from the Istituto Pasteur, Fondazione Cenci Bolognetti, the European NoE EMBIC within FP6 (Contract number LSHN-CT-2004-512040), Istituto Italiano di Tecnologia, and Ministero dell'Istruzione, dell'Università e della Ricerca (Ricerche Universitarie), and from Università Politecnica delle Marche. There are no conflicts of interest to declare.

Pleiotropic effects of metformin: Shaping the microbiome to manage type 2 diabetes and postpone ageing

Metformin is the first-choice therapy to lower glycaemia and manage type 2 diabetes. Continuously emerging epidemiological data and experimental models are showing additional protective effects of metformin against a number of age-related diseases (ARDs), e.g., cardiovascular diseases and cancer. This evidence has prompted the design of a specific trial, i.e., the Targeting Aging with Metformin (TAME) trial, to test metformin as an anti-ageing molecule. However, a unifying or prevailing mechanism of action of metformin is still debated. Here, we summarize the epidemiological data linking metformin to ARD prevention. Then, we dissect the deeply studied mechanisms of action explaining its antihyperglycemic effect and the putative mechanisms supporting its anti-ageing properties, focusing on studies using clinically pertinent doses. We hypothesize that the molecular observations obtained in different models with metformin could be indirectly mediated by its effect on gut flora. Novel evidence suggests that metformin reshapes the human microbiota, promoting the growth of beneficial bacterial species and counteracting the expansion of detrimental bacterial species. In turn, this action would influence the balance between pro- and anti-inflammatory circulating factors, thereby promoting glycaemic control and healthy ageing. This framework may reconcile diverse observations, providing information for designing further studies to elucidate the complex interplay between metformin and the metabiome harboured in mammalian body compartments, thereby paving the way for innovative, bacterial-based therapeutics to manage type 2 diabetes and foster a longer healthspan.

Attenuation of Listeria monocytogenes Virulence by Cannabis sativa L. Essential Oil

Anti-virulence strategies are being explored as a novel approach to combat pathogens. Such strategies include inhibition of surface adhesion, tissue invasion, toxin production, and/or interference with the gene regulation of other virulence traits. Listeria monocytogenes, the causative agent of listeriosis, is a facultative intracellular food pathogen characterized by a wide distribution in the environment. Its ability to persist within biofilms and to develop resistance to sanitizers is the cause of significant problems in food processing plants and of steep costs for the food industry. In humans, the treatment of listeriosis is hampered by the intracellular location of listeriae and the poor intracellular penetration of some antibiotics. Eleven L. monocytogenes isolates from patients who were diagnosed with invasive listeriosis in Italy in 2014-2016 were studied. This in vitro and in vivo study explored the antibacterial and anti-virulence properties of a steam-distilled essential oil of Cannabis sativa L., which is being intensively investigated for its high content in powerful bioactive phytochemicals. Susceptibility experiments demonstrated a moderate bactericidal activity of the essential oil (Minimum Bactericidal Concentration > 2048 μg/mL). Assessment of the effects of sublethal concentrations of the essential oil on L. monocytogenes virulence traits demonstrated a significant action on motility. Listeriae were non-motile after exposure to the essential oil. Light and scanning electron microscopy documented aggregates of listeriae with the flagella trapped inside the cluster. Real-time RT-PCR experiments showed downregulation of flagellar motility genes and of the regulatory gene prfA. The ability to form biofilm and to invade Caco-2 cells was also significantly reduced. Galleria mellonella larvae infected with L. monocytogenes grown in presence of sublethal concentrations of the essential oil showed much higher survival rates compared with controls, suggesting that the extract inhibited tissue invasion. Food contamination with L. monocytogenes is a major concern for the food industry, particularly for plants making ready-to-eat and processed food. The present work provides a baseline in the study of the anti-virulence properties of the C. sativa essential oil against L. monocytogenes. Further studies are needed to understand if it could be used as an alternative agent for the control of L. monocytogenes in food processing plants.

Short-term sustained hyperglycaemia fosters an archetypal senescence-associated secretory phenotype in endothelial cells and macrophages

Diabetic status is characterized by chronic low-grade inflammation and an increased burden of senescent cells. Recently, the senescence-associated secretory phenotype (SASP) has been suggested as a possible source of inflammatory factors in obesity-induced type 2 diabetes. However, while senescence is a known consequence of hyperglycaemia, evidences of SASP as a result of the glycaemic insult are missing. In addition, few data are available regarding which cell types are the main SASP-spreading cells in vivo. Adopting a four-pronged approach we demonstrated that: i) an archetypal SASP response that was at least partly attributable to endothelial cells and macrophages is induced in mouse kidney after in vivo exposure to sustained hyperglycaemia; ii) reproducing a similar condition in vitro in endothelial cells and macrophages, hyperglycaemic stimulus largely phenocopies the SASP acquired during replicative senescence; iii) in endothelial cells, hyperglycaemia-induced senescence and SASP could be prevented by SOD-1 overexpression; and iiii) ex vivo circulating angiogenic cells derived from peripheral blood mononuclear cells from diabetic patients displayed features consistent with the SASP. Overall, the present findings document a direct link between hyperglycaemia and the SASP in endothelial cells and macrophages, making the SASP a highly likely contributor to the fuelling of low-grade inflammation in diabetes.

Diagnostic value of microRNAs in asbestos exposure and malignant mesothelioma: systematic review and qualitative meta-analysis

Background

Asbestos is a harmful and exceptionally persistent natural material. Malignant mesothelioma (MM), an asbestos-related disease, is an insidious, lethal cancer that is poorly responsive to current treatments. Minimally invasive, specific, and sensitive biomarkers providing early and effective diagnosis in high-risk patients are urgently needed. MicroRNAs (miRNAs, miRs) are endogenous, non-coding, small RNAs with established diagnostic value in cancer and pollution exposure. A systematic review and a qualitative meta-analysis were conducted to identify high-confidence miRNAs that can serve as biomarkers of asbestos exposure and MM.

Methods

The major biomedical databases were systematically searched for miRNA expression signatures related to asbestos exposure and MM. The qualitative meta-analysis applied a novel vote-counting method that takes into account multiple parameters. The most significant miRNAs thus identified were then subjected to functional and bioinformatic analysis to assess their biomarker potential.

Results

A pool of deregulated circulating and tissue miRNAs with biomarker potential for MM was identified and designated as “mesomiRs” (MM-associated miRNAs). Comparison of data from asbestos-exposed and MM subjects found that the most promising candidates for a multimarker signature were circulating miR-126-3p, miR-103a-3p, and miR-625-3p in combination with mesothelin. The most consistently described tissue miRNAs, miR-16-5p, miR-126-3p, miR-143-3p, miR-145-5p, miR-192-5p, miR-193a-3p, miR-200b-3p, miR-203a-3p, and miR-652-3p, were also found to provide a diagnostic signature and should be further investigated as possible therapeutic targets.

Conclusion

The qualitative meta-analysis and functional investigation confirmed the early diagnostic value of two miRNA signatures for MM. Large-scale, standardized validation studies are needed to assess their clinical relevance, so as to move from the workbench to the clinic.

Identification of miR-31-5p, miR-141-3p, miR-200c-3p, and GLT1 as human liver aging markers sensitive to donor-recipient age-mismatch in transplants

To understand why livers from aged donors are successfully used for transplants, we looked for markers of liver aging in 71 biopsies from donors aged 12–92 years before transplants and in 11 biopsies after transplants with high donor–recipient age‐mismatch. We also assessed liver function in 36 age‐mismatched recipients. The major findings were the following: (i) miR‐31‐5p, miR‐141‐3p, and miR‐200c‐3p increased with age, as assessed by microRNAs (miRs) and mRNA transcript profiling in 12 biopsies and results were validated by RT–qPCR in a total of 58 biopsies; (ii) telomere length measured by qPCR in 45 samples showed a significant age‐dependent shortage; (iii) a bioinformatic approach combining transcriptome and miRs data identified putative miRs targets, the most informative being GLT1, a glutamate transporter expressed in hepatocytes. GLT1 was demonstrated by luciferase assay to be a target of miR‐31‐5p and miR‐200c‐3p, and both its mRNA (RT–qPCR) and protein (immunohistochemistry) significantly decreased with age in liver biopsies and in hepatic centrilobular zone, respectively; (iv) miR‐31‐5p, miR‐141‐3p and miR‐200c‐3p expression was significantly affected by recipient age (older environment) as assessed in eleven cases of donor–recipient extreme age‐mismatch; (v) the analysis of recipients plasma by N‐glycans profiling, capable of assessing liver functions and biological age, showed that liver function recovered after transplants, independently of age‐mismatch, and recipients apparently ‘rejuvenated’ according to their glycomic age. In conclusion, we identified new markers of aging in human liver, their relevance in donor–recipient age‐mismatches in transplantation, and offered positive evidence for the use of organs from old donors.

Progress of research on microRNAs with diagnostic value in asbestos exposure: A call for method standardization

Malignant mesothelioma (MM) is an insidious, lethal asbestos-related cancer that is poorly responsive to current treatments. Specific and sensitive biomarkers providing early MM diagnosis in exposed subjects, who are at high-risk of developing it, are sorely needed. MicroRNAs (miRNAs) are endogenous, non-coding, small RNAs with a well-established diagnostic role in cancer and pollution exposure. In a recent systematic review and qualitative meta-analysis followed by a functional investigation, we examined all the available data on the miRNA biomarkers involved in asbestos exposure and MM pathways. This invited commentary aims to provide an insightful critique into the state of the art of the research into clinically relevant miRNA biomarkers, highlighting the strengths and weaknesses of current research efforts in this field. It also reviews the suggestions advanced to improve biomarker development productivity and the translation of research results into clinical practice, stressing that multicenter multidisciplinary studies adopting standardized methods and protocol sharing are the key to move from the workbench to the clinic.

Epigenetic mechanisms of endothelial dysfunction in type 2 diabetes

The development of type-2 diabetes mellitus (T2DM) and its complications is largely due to the complex interaction between genetic factors and environmental influences, mainly dietary habits and lifestyle, which can either accelerate or slow down disease progression. Recent findings suggest the potential involvement of epigenetic mechanisms as a crucial interface between the effects of genetic predisposition and environmental factors. The common denominator of environmental factors promoting T2DM development and progression is that they trigger an inflammatory response, promoting inflammation-mediated insulin resistance and endothelial dysfunction. Proinflammatory stimuli, including hyperglycemia, oxidative stress, and other inflammatory mediators, can affect epigenetic mechanisms, altering the expression of specific genes in target cells without changes in underlying DNA sequences. DNA methylation and post-translational histone modifications (PTHMs) are the most extensively investigated epigenetic mechanisms. Over the past few years, non-coding RNA, including microRNAs (miRNAs), have also emerged as key players in gene expression modulation. MiRNAs can be actively released or shed by cells in the bloodstream and taken up in active form by receiving cells, acting as efficient systemic communication tools. The miRNAs involved in modulation of inflammatory pathways (inflammamiRs), such as miR-146a, and those highly expressed in endothelial lineages and hematopoietic progenitor cells (angiomiRs), such as miR-126, are the most extensively studied circulating miRNAs in T2DM. However, data on circulating miRNA signatures associated with specific diabetic complications are still lacking. Since immune cells and endothelial cells are primarily involved in the vascular complications of T2DM, their relative contribution to circulating miRNA signatures needs to be elucidated. An integrated approach encompassing different epigenetic mechanisms would have the potential to provide new mechanistic insights into the genesis of diabetes and its severe vascular complications and identify a panel of epigenetic markers with diagnostic/prognostic and therapeutic relevance.

Circulating miR-21, miR-146a and Fas ligand respond to postmenopausal estrogen-based hormone replacement therapy--a study with monozygotic twin pairs

Biological aging is associated with physiological deteriorations, which are partly due to changes in the hormonal profile. MicroRNAs regulate various processes associated with cell senescence; differentiation, replication and apoptosis. Serum microRNAs have potential to serve as noninvasive markers for diagnostics/prognostics and therapeutic targets. We analysed the association of estrogen-based hormone replacement therapy (HRT) with selected microRNAs and inflammation markers from the serum, leukocytes and muscle biopsy samples from 54 to 62 year-old postmenopausal monozygotic twins (n=11 pairs) discordant for HRT usage. Premenopausal 30-35 year-old women (n=8) were used as young controls. We focused on the hormonal aging and on the interaction between HRT use and the modulation of miR-21, miR-146a and classical inflammation markers. Fas-ligand was analysed since it functions in both apoptosis and inflammation. The inflammatory profile was healthier among the premenopausal women compared to the postmenopausal twins. Serum miR-21 and miR-146a levels and FasL concentrations were lower in HRT users compared to their non-using co-twins, demonstrating their responsiveness to HRT. Based on the pairwise FasL analysis, FasL concentration is likely to be genetically controlled. Overall, we suggest that postmenopausal estrogen deficiency sustains the development of "inflamm-aging". Estrogen sensitive, specific circulating microRNAs could be potential, early biomarkers for age-associated physiological deteriorations.

Age- and glycemia-related miR-126-3p levels in plasma and endothelial cells

Circulating miR-126-3p levels were determined in 136 healthy subjects (CTRs) aged 20-90 years and 193 patients with type-2 diabetes mellitus (T2DMs) aged 40-80 years, to explore the combined effect of age and glycemic state on miR-126-3p expression. Moreover, intra/extracellular miR-126-3p levels were measured in human endothelial cells (HUVECs) undergoing senescence under normo/hyper-glycemic conditions. Plasma miR-126-3p was significantly higher in the oldest compared with the youngest CTRs ( <45 vs. >75 years; relative expression: 0.27±0.29 vs. 0.48±0.39, p=0.047). Age-based comparison between CTRs and T2DM demonstrated significantly different miR-126-3p levels only in the oldest (0.48±0.39 vs. 0.22±0.23, p<0.005). After multiple adjustments, miR-126-3p levels were seen to be lower in patients with poor glycemic control, compared with age-matched CTRs. The age-related increase in plasma miR-126-3p found in CTRs was paralleled by a 5/6-fold increase in intra/extracellular miR-126-3p in in vitro-cultured HUVECs undergoing senescence. Notably, significant down- regulation of SPRED-1 protein, a validated miR-126-3p target, was found in senescent HUVECs. Moreover, miR-126-3p expression was down-regulated in intermediate-age HUVECs grown in high-glucose medium until senescence. Aging/senescence-associated miR-126-3p up-regulation is likely a senescence-associated compensatory mechanism that is blunted when endothelial cells are exposed to high glucose levels, a phenomenon that probably occurs in vivo in T2DM patients.

Anti-inflammatory effect of ubiquinol-10 on young and senescent endothelial cells via miR-146a modulation

Clinical evidence demonstrates that ubiquinol-10, the reduced active form of coenzyme Q10 (CoQ10H₂), improves endothelial function through its antioxidant and probably its anti-inflammatory properties. We previously reported that a biomarker combination including miR-146a, its target protein IL-1 receptor-associated kinase (IRAK-1), and released interleukin (IL)-6, here collectively designated as MIRAKIL, indicates senescence-associated secretory phenotype (SASP) acquisition by primary human umbilical vein endothelial cells (HUVECs). We explore the ability of short- and long-term CoQ10H₂ supplementation to affect MIRAKIL in HUVECs, used as a model of vascular aging, during replicative senescence in the absence/presence of lipopolysaccharide (LPS), a proinflammatory stimulus. Senescent HUVECs had the same ability as young cells to internalize CoQ10 and exhibit an improved oxidative status. LPS-induced NF-κB activation diminished after CoQ10H₂ pretreatment in both young and senescent cells. However, short-term CoQ10H₂ supplementation attenuated LPS-induced MIRAKIL changes in young cells; in senescent cells CoQ10H₂ supplementation significantly attenuated LPS-induced miR-146a and IRAK-1 modulation but failed to curb IL-6 release. Similar results were obtained with long-term CoQ10H₂ incubation. These findings provide new insights into the molecular mechanisms by which CoQ10H₂ stems endothelial cell inflammatory responses and delays SASP acquisition. These phenomena may play a role in preventing the endothelial dysfunction associated with major age-related diseases.

MicroRNAs linking inflamm-aging, cellular senescence and cancer

Epidemiological and experimental data demonstrate a strong correlation between age-related chronic inflammation (inflamm-aging) and cancer development. However, a comprehensive approach is needed to clarify the underlying molecular mechanisms. Chronic inflammation has mainly been attributed to continuous immune cells activation, but the cellular senescence process, which may involve acquisition of a senescence-associated secretory phenotype (SASP), can be another important contributor, especially in the elderly. MicroRNAs (miRs), a class of molecules involved in gene expression regulation, are emerging as modulators of some pathways, including NF-κB, mTOR, sirtuins, TGF-β and Wnt, that may be related to inflammation, cellular senescence and age-related diseases, cancer included. Interestingly, cancer development is largely avoided or delayed in centenarians, where changes in some miRs are found in plasma and leukocytes. We identified miRs that can be considered as senescence-associated (SA-miRs), inflammation-associated (inflamma-miRs) and cancer-associated (onco-miRs). Here we review recent findings concerning three of them, miR-21, -126 and -146a, which target mRNAs belonging to the NF-κB pathway; we discuss their ability to link cellular senescence, inflamm-aging and cancer and their changes in centenarians, and provide an update on the possibility of using miRs to block accumulation of senescent cells to prevent formation of a microenvironment favoring cancer development and progression.

Putative miRNAs for the diagnosis of dyslexia, dyspraxia, and specific language impairment

Disorders of human communication abilities can be classified into speech and language disorders. Speech disorders (e.g., dyspraxia) affect the sound generation and sequencing, while language disorders (e.g., dyslexia and specific language impairment, or SLI) are deficits in the encoding and decoding of language according to its rules (reading, spelling, grammar). The diagnosis of such disorders is often complicated, especially when a patient presents more than one disorder at the same time. The present review focuses on these challenges. We have combined data available from the literature with an in silico approach in an attempt to identify putative miRNAs that may have a key role in dyspraxia, dyslexia and SLI. We suggest the use of new miRNAs, which could have an important impact on the three diseases. Further, we relate those miRNAs to the axon guidance pathway and discuss possible interactions and the role of likely deregulated proteins. In addition, we describe potential differences in expressional deregulation and its role in the improvement of diagnosis. We encourage experimental investigations to test the data obtained in silico.

MiR-146a as marker of senescence-associated pro-inflammatory status in cells involved in vascular remodelling

In order to identify new markers of vascular cell senescence with potential in vivo implications, primary cultured endothelial cells, including human umbilical vein endothelial cells (HUVECs), human aortic endothelial cells (HAECs), human coronary artery endothelial cells (HCAECs) and ex vivo circulating angiogenic cells (CACs), were analysed for microRNA (miR) expression. Among the 367 profiled miRs in HUVECs, miR-146a, miR-9, miR-204 and miR-367 showed the highest up-regulation in senescent cells. Their predicted target genes belong to nine common pathways, including Toll-like receptor signalling (TLR) that plays a pivotal role in inflammatory response, a key feature of senescence (inflammaging). MiR-146a was the most up-regulated miR in the validation analysis (>10-fold). Mimic and antagomir transfection confirmed TLR's IL-1 receptor-associated kinase (IRAK1) protein modulation in both young and senescent cells. Significant correlations were observed among miR-146a expression and β-galactosidase expression, telomere length and telomerase activity. MiR-146a hyper-expression was also validated in senescent HAECs (>4-fold) and HCAECs (>30-fold). We recently showed that CACs from patients with chronic heart failure (CHF) presented a distinguishing feature of senescence. Therefore, we also included miR-146a expression determination in CACs from 37 CHF patients and 35 healthy control subjects (CTR) for this study. Interestingly, a 1,000-fold increased expression of miR-146a was observed in CACs of CHF patients compared to CTR, along with decreased expression of IRAK1 protein. Moreover, significant correlations among miR-146a expression, telomere length and telomerase activity were observed. Overall, our findings indicate that miR-146a is a marker of a senescence-associated pro-inflammatory status in vascular remodelling cells.

Toll like receptor signaling in "inflammaging": microRNA as new players

The age-related changes of immune system functions are complex phenomena incompletely understood. The acquired immune system shows a functional decline in ability to respond to new pathogens during aging, whereas serum levels of inflammatory cytokines are increased with age. The source of this age-related systemic chronic inflammation, named inflammaging, was mainly attributed to the progressive activation of immune cells over time. However, recent studies have shown that the process of cellular senescence can be an important additional contributor to chronic inflammation, since senescent cells acquire a phenotype named “senescence-associated secretory phenotype” (SASP), characterized by the enhanced secretion of many inflammation modulators. Pathogen-associated molecular pattern receptors, in particular Toll-like receptors (TLRs), are key molecules in the response of innate immunity cells to pathological stimuli. An intriguing and innovative hypothesis is that the dysfunction of TLRs signaling and the acquisition of SASP can be two interconnected phenomena. The TLR family, including receptors and co-effector molecules, do not show a consistent age-dependent change across model systems. However, there is evidence for impaired downstream signaling events, including inhibition of positive and activation of negative modulators of TLR signaling. MicroRNAs (miRNAs) are a newly discovered class of gene regulators acting as post-transcriptional repressors of a number of genes. The miRNA property to finely-tune gene expression makes them right for immune system regulation, which requires precise control for proper activity. We reviewed evidences suggesting that miRNAs can modulate TLR signaling mainly by three different mechanisms: 1) miRNAs can directly target components of the TLR signaling system, 2) miRNA expression can be directly regulated by TLRs pathway activation and 3) miRNAs can directly activate the RNA-sensing TLRs, like TLR-8, in humans. We also reviewed how TLR signaling is modulated by miRNAs during aging, and how an impaired miRNAs/TLR signaling interaction in immune system cells and related cells, i.e. endothelial cells and adipocytes, can contribute to inflammaging observed in normal aging. Interestingly, this impairment appears accelerated in presence of the majors age-related diseases, such as cardiovascular diseases, diabetes, neurodegenerative diseases and cancers.

Age-related differences in the expression of circulating microRNAs: miR-21 as a new circulating marker of inflammaging

Circulating microRNAs (miRs) have been investigated as diagnostic/prognostic biomarkers in human diseases. However, little is known about their expression throughout the aging process. Eleven healthy individuals aged 20, 80 and 100 years underwent miR plasma profiling. The validation cohort consisted of 111 healthy adults (CTR) aged 20-105 years and included 30 centenarians. In addition, 34 patients with cardiovascular disease (CVD) and 15 healthy centenarian offspring (CO) were enrolled. An exploratory factorial analysis grouped the miRs into three main factors: factor 1 primarily higher in 20-year-old subjects, but these differences did not reach statistical significance, factor 2 primarily higher in octogenarians and factor 3 primarily higher in centenarians. MiR-21, the most highly expressed miR of factors 2 and 3, was further validated, confirming the differences in the age groups. MiR-21 expression was higher in the CVD patients and lower in the CO compared to the age-matched CTR. MiR-21 was correlated with C-reactive protein and fibrinogen levels. TGF-β signaling was the predicted common pathway targeted by miRs of factors 2 and 3. TGF-βR2 mRNA, a validated miR-21 target, showed the highest expression in the leukocytes from a subset of the octogenarians. Our findings suggest that miR-21 may be a new biomarker of inflammation.

Leukocyte telomere length is associated with complications of type 2 diabetes mellitus

OBJECTIVE

The key goal of diabetes management is to prevent complications. While the patho-physiological mechanisms responsible for diabetes complications have been extensively studied, at present it is impossible to predict which patient with diabetes could develop complications. In recent years, the role of leukocyte telomere length in the pathogenesis of cardiovascular disease and Type 2 diabetes has been investigated. However, studies aiming to investigate the role of telomeres in the development and progression of Type 2 diabetes, as well as diabetic complications, are still lacking. As a consequence, this study aimed to verify whether leukocyte telomere length is associated with the presence and the number of diabetic complications in a sample of patients with Type 2 diabetes.

METHODS

This is a cross-sectional study. Nine hundred and one subjects were enrolled, including 501 patients with Type 2 diabetes, of whom 284 had at least one complication and 217 were without complications, and 400 control subjects. Leukocyte telomere length was measured by quantitative real-time PCR.

RESULTS

Patients with diabetes complications had significantly shorter leukocyte telomere length than both patients without diabetes complications and healthy control subjects. Moreover, among patients with diabetes complications, leukocyte telomere length became significantly and gradually shorter with the increasing number of diabetes complications. The magnitude of the effect of the decrease of the abundance of telomeric template vs. a single-copy gene length (T/S ratio) on complications is described by the estimated odds ratio OR=5.44 (95%CI 3.52-8.42).

CONCLUSIONS

The results of the study support the hypothesis that telomere attrition may be a marker associated with the presence and the number of diabetic complications.

Decitabine, differently from DNMT1 silencing, exerts its antiproliferative activity through p21 upregulation in malignant pleural mesothelioma (MPM) cells

Malignant pleural mesothelioma (MPM) is a locally aggressive neoplasm, principally linked to asbestos fibres exposure. Strong evidences associate this pollutant with induction of DNA breaks, aberrant chromosomes segregation and important chromosomal rearrangements, considered crucial events in malignant transformation. A considerable contribution to cellular transformation in MPM is also given by the presence of high genomic instability, as well as by the increased DNA methylation, and consequent decreased expression, of tumor-suppressor genes. In this study we first demonstrated that MPM cells are characterized by a decreased methylation level of pericentromeric DNA sequences which can justify, at least in part, the genomic instability observed in this neoplasia. Concomitantly, we found a paradoxical increased expression of DNMT1, the most expressed DNA methyltransferases in MPM cells, DNMT3a and all five isoforms of DNMT3b. Thus, we compared two experimental strategies, DNMT1 silencing and usage of a demethylating agent (5-aza-2'-deoxycytidine or Decitabine), both theoretically able to revert the locally hypermethylated phenotype and considered potential future therapeutic approaches for MPM. Interestingly, both strategies substantially decrease cell survival of MPM cells but the antitumor activity of Decitabine, differently from DNMT1 silencing, is mediated, at least in part, by a p53-independent p21 upregulation, and is characterized by the arrest of MPM cells at the G2/M phase of the cell cycle. These results indicate that the two approaches act probably through different mechanisms and, thus, that DNMT1 silencing can be considered an effective alternative to Decitabine for cancer treatment.